Read two sentences from the exposition of the motto of Fudan University by its first President, Dr. Wen, "Know something in everything" and "Know everything in something", which seem to be quite true. I search for their source, but could not find one. The closest I can get is an anonymous quote "A Ph.D. is one who knows everything about something and knows something about everything". Indeed, a successful Ph.D. must have breadth in knowledge (know something in everything), but also depth (know everything in something). Without breadth, research findings will have limited impact and researchers would lose any vision on what has been discovered. Without depth, one would not get solid work done and research findings would be just superficial. Thus, a Ph.D. student needs to work on both.
The Nobel Prize in Physics 1989 was divided, one half awarded to Norman F. Ramsey "for the invention of the separated oscillatory fields method and its use in the hydrogen maser and other atomic clocks" , the other half jointly to Hans G. Dehmelt and Wolfgang Paul "for the development of the ion trap technique" . The Nobel Prize in Physics 1997 was awarded jointly to Steven Chu, Claude Cohen-Tannoudji and William D. Phillips "for development of methods to cool and trap atoms with laser light" . The Nobel Prize in Physics 2001 was awarded jointly to Eric A. Cornell, Wolfgang Ketterle and Carl E. Wieman "for the achievement of Bose-Einstein condensation in dilute gases of alkali atoms, and for early fundamental studies of the properties of the condensates" . The Nobel Prize in Physics 2005 was divided, one half awarded to Roy J. Glauber "for his contribution to the quantum theory of optical coherence" , the other half jointly to John L. Hall and Theodor W. Hänsch "for their contributions to the development of laser-based precision spectroscopy, including the optical frequency comb technique" . The Nobel Prize in Physics 2012 was awarded jointly to Serge Haroche and David J. Wineland "for ground-breaking experimental methods that enable measuring and manipulation of individual quantum systems" 时隔六年之后，诺贝尔物理学奖再一次颁给了量子光学领域的奠基者。从上面的颁奖词中，可以见到，从 1989 年到现在共有五次的物理学奖颁给了量子光学领域的开创者，这些贡献在于实现前所未有的精密技术的进步和理论贡献。所有这些进步，正在为我们描述一个越来越真实的量子世界。 我们都知道，量子力学的建立改变了我们对于真实世界的看法。现实的世界在一个物理学家的眼中，或者任何一个明白量子理论的人的眼中，和平常的人是截然不同的,这是一个奇异的让人难以理解的空间。 当我们把这种理解用于所讨论的问题的时候，比如核物理，粒子物理，固体物理等等，我们得到了经典理念不能得到的答案。但是由于我们讨论的往往是非常大的客体，或者是非常多的同样的客体，所以那些单个客体的最为奇异的现象并没有体现出来。早期的量子观念更多的是帮我们理解世界，而不是直接来操控世界。 我们可以把一个火箭送入太空，是因为我们通晓了牛顿的万有引力定律。利于这个规律，我么可以非常精确的对于火箭进行操控。同样的道理，当我们深入到非常细小的世界的时候，比如单个原子，或者单个的离子，甚至是一个光子，我们可以去操控他们么？ 如此小的客体完全是由量子力学的规律来描述的 , 他们的状态当和其它客体接触的时候会必然的发生变化 , 这给我们直接操控他们带来了极大的困难 . 一方面 , 这些小的客体必然会和环境发生作用 , 从而发生变化 , 另一方面 , 当我们去操控他们的时候 , 也必然会产生扰动 . 这是一个看起来似乎很简单 , 但是却异常困难的问题 . 量子光学和量子力学的基本问题联系非常紧密 . 许多关于量子力学的疑惑都是在量子光学领域得到解决的 . 为什么呢 ? 原因很简单 , 因为激光的发明以及许多漂亮的光学现象 . 就好象我们的眼睛是最敏感的感觉器官一样 , 激光技术和许多光学现象能够让我们更清晰的看到微观的世界 , 乃至通过光与原子、离子、腔的作用 , 使得我们能够对于原子、离子和光子本身进行精确的操控。 今年的诺贝尔物理学奖就是奖励给了在这个领域做出巨大贡献的两位科学家 , 他们的工作为我们精密操控离子和光子的状态成为可能 . 其实 , 这个领域有许多人都做出了贡献 , 我相信还会有更多的人被授予这个最高荣誉 . 而量子光学以及最近二十年来高速发展的量子信息会被更多的人关注 ，并且为我们打开一个真实的量子世界.
One earth, one life ------Human common belief in future Xiao Ming Wang Hubei University of Traditional Chinese Medicine China E-mail: shermanwang@yahoo.com.cn , foxglove@163.com Abstract: The author proposed a new perspective to contemplate the nature of life and pursue the philosophy of life and healthy. He first g a ve the definition of what is one life sufficiently and necessarily. Any one thing or one body which has following five characteristics is one life: from small to big (growth); from one to two or one generation to next generation (reproduction); self-regulation; can be killed; age to death; he concluded the basic tendency of life development on the earth, discuss ed the relation of human life and the life surround human. The human life faced the challenge in era of globalization . Propose d human should have a community common belief in future: one earth is one life. All people of whatever country or ethnic should love one earth life and preserve the life of earth . It is determine the destiny of the humankind Keywords : the definition of one life; human common belief; the development of life; the philosophy of life and healthy; the challenge of globalization 1. I ntroduction As the developing of internet technique and globalization of world economy, the knowledge of science and technology spread all over the world. Human society has tremendous change. The environment of the earth also changes sharply. All life on the earth inevitably to adapt to this new tendency. What life may survival in future on earth? Human behavior has made a great impact on the system of all bio-organisms on the earth . T he integration of t he world economy gradually impacts all human society to become one life organism. But this change may also cause many great challenges for every people survive in the world life system. It may cause financial crisis, political conflict, military competition , nuclear war and other social problem , or disaster , or tragedy. One human life need all man has common belief. Only human common belief can make human have common criterion of human behavior that can judge about what is correct and what is wrong. H uman also need to regulate their behavior to accommodate to the change of environment . Without common belief, human life will has endless social and state conflicts. 2. The concept of one life and The development of life on earth Aristotle said that all man by nature want to know. Man wants to know every being as being surrounded him and every thing about himself. What is the most general and fundamental inquiry that man wants to know? What is life? How is the life on the earth developing? What is the relation of the human life and the lives surrounded us? Because the abundan ce of phenomena of life, people are perplexed by the concept of what is life. The current understanding is descriptive. Life is considered a characteristic of organisms that exhibit all or most of the following: Homeostasis :. Organization :. Metabolism :. Growth :. Adaptation : Response to stimuli :. Reproduction : Although it is still a challenge for scientists and philosophers to define life in unequivocal terms, we can precisely, sufficiently and necessarily give a definition of what is one life. Any one thing or one body has following five characteristics that can be said one life: growth (from small to big); reproduction (from one to two or from one generation to second generation); self-regulation; can been killed; age to death. Each one life has four period of life expectation: birth; growth; reproduction; death. From this philosophical perspective, we can better understand the life of human body, human society and the lives surrounded human. We can better survive on the earth, preventing our lives from diseases, wars and social tragedy. We can better treat the relation of the human life and the lives surrounded us and adjust our life to coordinative with the environment, protecting the environment and prolonging our lifespan. It is so common and important question that everyone should know what is one life. One life is a process, not a pure substance. Any definition must be sufficiently broad to encompass all life with which we are familiar, and must be necessarily general to include life that may be fundamentally different from life on Earth. The holistic idea of the Earth as an integrated whole, a living being, has a long tradition, but the first scientific discussion was by the Scottish scientist James Hutton . James lovelock first proposes the Gaia hypothesis that all organisms and their inorganic surroundings on Earth are closely integrated to form a single and self-regulating complex system , maintaining the conditions for life on the planet. According to the perspective that we suggested, you know each cell of you body has one life. All cells of yours compose one body, which is your one life. Your central nervous system regulates all lives of your cells, adjusted whole body to adapt the change of surroundings. Your body is one complicate cell social organism. Your family is one life. Your company is one life. The city you lived in is one life. Your native is one life. Your country is one life. The whole biosphere of the earth is one life. It regulates all lives on the earth, self- sustaining itself from one generation to second generation and keeping all material on earth surface to recycle, especially carbon , nitrogen and water recycling . It transport solar energy to biological energy and transmits energy on the surface of the earth. From the history of life developing on earth as we known, we can conclude: The earth biosphere consist of many different life species, life types, and life levels. Same life species live on same energy and materials in same way. Different life species live on different material or different energy or in different space. A species of life can differentiate to many different types of life. Different life type live on same material in same space has different function. A level of life may be composed of many life types and/or life species,. More life levels sustain the life more stable on the earth. Which kind of life can survive a long lifespan? The development of life has three tendencies: Life Species evolution --- survival of the fittest , which Charles Darwin first proposed the T heory of Evolution; Life Type specialization ---- survival of the most efficient, Life Level multiplication --- survival of the more stable homeostasis system. Chemical material transform, energy transmit, information transport t more efficient in multi level life system. 3. T he relationship of human life and the life around human According to the perspective we suggested above, human life is a part of one earth life. One earth life has self-regulated all species of life on the biosphere; one life is an open self-regulation system. No life can survive in an isolated close space consistently. This has been demonstrated by the Biosphere 2 in Oracle, Arizona (USA) . As the climate change, all life species should evolve to adapt the change. All life level control wh at species may sustain to survive. Human life belongs to his ecological life . H uman has no ability to control his ecological life, but human life or human behavior may force the ecological life change or evolution. We all often see some specie life suddenly burst out in some ecological system, all of this species regulated by his ecological life when the species life unbalance. If the life specie sharply unbalance, that may cause many species life extinct. Some new evolve specie life bring out. Or wholly ecological life dies . The more specie life in one ecological life, the more stable ecological system, and the stronger the one ecological life is. Otherwise on contrast the ecological life is weak er . As the human life become too strong, it may cause may other species life extinct. This behavior wills weak the ecological life. All material should recycle on biosphere of earth. In o ne health life , chemical materials transform continua lly , energy transport in balance. The e arth rotates day and night. It causes s olar light energy transport on earth unbalance on the surface. This unbalance cause s the transport ation of energy and material of the earth unsmooth . Thus lead the climate unstable a nd atmosphere recycle unstable. At the life beginning on the earth, there was only one kind of original primitive specie of life. As this life was from one to two, and more, the shortage of space and energy and material happened . Some move d to other place or space to survive, some evolve d new specie life to live on new material and energy, some organize d more level to more efficiently use material and energy . A ll of this improves the climate stable and environment stable. Life grows gloriously on earth. 4. T he challenge of human life in an Era of Globalization As the developing of human society and economical globalization, the human gradually been integrated to one human life. This also causes great challenge for the survival of human life. Different country and ethnic have different history, culture and value. They are on different developing level. Different h uman r ights conception and c ultural d iversity may cause many conflicts. The growing economy disparity in wealth and access to resources, coincide with an alarming increase in violence, poverty and unemployment, and the erosion of environmental stability. At the same time, previously isolated peoples are being brought together voluntarily and involuntarily by the increasing integration of markets, the emergence of new regional political alliances, and remarkable advances in telecommunications and transportation that have push all people to become a life organism which need more complicate self-regulate mechanism. . This situation sharpens a long-standing dilemma: Li fe existed on the earth face many challenges and risk . M any factors can kill the life. Some unbalances may cause human social tragedy: How human can keep human life healthy developing and prevent from economic and social crisis? Does our generation can find enough wisdom to solve the problem? W henever and what ever kind change take place between groups of human, nobody can change that all human life belong a part of an earth life, one earth life certainly regulate all human life in itself own natural mechanism. 5. Human common belief Although Human life has not integrated to become one life completely and perfectly nowadays, human life certainly belongs to one earth life . I n the history of human, human individual or organisms or country have no ability to destroy the one earth life . A s the science and technology develop in whole world in future and economy growth and environment destruction, the behavior of some country or some individual may have some ability to do some thing destroy the one earth life that the earth life can not self-regulate to repair the damage of human behavior, that will be made the one earth life can not from one generation to next generation. The life on the earth is end. As the human life gradually to become one single life, wholly people need common belief. Only have common belief that human can build up a series of self-regulation method to sustain one human life with one earth life harmony . P eople from different culture and different history can set up same criterion to have international law or rule to regulate human behavior, to force human life adapt to one earth life change .and prolong human life expectation . The development of human economy system and politics system is more health , social stability economic prosperous keep the life system harmony growth and reproduction . Only all human have common belief can rescued human life from nuclear war and massacre . without common belief , the growth of country must lead the contest of the material source and space. Different political philosophy can not coexist together finally the military war happens. Human society may conflict endless and individual may easily has mental disorder People believe G od he unwilling to do anything against Jesus, people believe Buddhism he unwilling to do anything against Buddha Mani. People believe Muslim he unwilling to do anything against Mohammed. People believe one earth is one life, he unwilling to do anything harmful the life system of the earth. Although some religious belief that earth is alive, that one earth is one life is scientific belief . I t is truth of life. WE BELIEVE IN THE SEARCH FOR TRUTH, THE QUEST FOR BEAUTY, AND THE STRUGGLE FOR EXCELLENCE; IS GOOD LIVING; A. Vaughan Abercrombie References Iztok Prezelj , HUMSEC Challenges in Conceptualizing and Providing Human Security http:// www. humsec .eu/cms/index.php?id=356 Diana Ayton-Shenker, The Challenge of Human Rights and Cultural Diversity ( Published by the United Nations Department of Public Information ) DPI/1627/HR--March 1995 http://www.un.org/rights/dpi1627e.htm Joseph Morales , The Definition of Life Psychozoan: A Journal of Culture Copyright 1998 http://www.baharna.com/philos/life.htm Daniel E Koshland Jr , The seven pillars of life . Science . Washington: Mar 22, 2002 . Vol. 295, Iss. 5563; pg. 2215, 2 pgs h ttp:// www.sciencemag.org/content/295/5563/2215.full.pdf Definition of life Encyclopedia Britannica 2007 Ultimate Reference Suite Wikipedia, Life http://en.wikipedia.org/wiki/Definition_of_life Wikipedia, Philosophy of biology http://en.wikipedia.org/wiki/Philosophy_of_biology A. V. Abercrombie, COMMON BELIEFS TO LIVE BY , http:// www.naccc.org/CMSUploads/474_ Common _ Beliefs .pdf
\title{\huge What is mass?\\~\\~\\ \large Chapter one: Mass in Newtonian Mechanics and Lagrangian mechanics} \author{Wang Xiong} \section{Introduction} \subsection{What is physics?} Physics is the study of matter and its motion through space and time. So the fundamental concepts of physics are matter, space-time, and motion. \subsection{What are the most important questions?} The fundamental questions of physics are: \begin{enumerate} \item What is the physical world made of? \item What is the structure of space-time? \item How do things change through space-time? \end{enumerate} The deeper understanding of these fundamental concepts and more profound answers to these fundamental questions, indicate the development of physical theory. \subsection{Matter and Mass} Of these fundamental concepts, mass is the modeling of matter. On the one hand, different properties of matter may lead to different concepts of mass. So we may discover many different physical attribute of matter, and use many different concepts of mass. On the other hand, some concepts may appear very different at first, but as we see deeper and deeper, we find a single and unified origin of these different concepts of mass. This kind of development of physic concept is very interesting and profound. So one may distinguish conceptually between many different attributes of mass or different physical phenomena that can be explained using the concept of mass There is no doubt that the problem of mass is one of the key problems of modern physics. \subsection{Overview of these series of talks} ``To see a World in a Grain of Sand, And a Heaven in a Wild'' We will try to see the development and the whole picture of theoretical physic through the evolution of the very fundamental concept of \emph{mass}. \begin{enumerate} \item The inertial mass in Newtonian mechanics \item The Newtonian gravitational mass \item Mass in Lagrangian formulism \item Mass in the special theory of relativity \item $E = MC^2$ \item Mass in quantum mechanics \item Principle of equivalence and general relativity \item The energy momentum tensor in general relativity \item Mass in the standard model of particle physics \item The higgs mechanism \end{enumerate} \section{Mass in Newtonian Mechanics} \subsection{Newton's three laws of motion} Newton's laws of motion are three physical laws that form the basis for classical mechanics. They describe the relationship between the forces acting on a body and its motion due to those forces. They have been expressed in several different ways over nearly three centuries, and can be summarized as follows: \begin{enumerate} \item First law: Every object continues in its state of rest, or of uniform motion in a straight line, unless compelled to change that state by external forces acted upon it. \item Second law: The acceleration a of a body is parallel and directly proportional to the net force F acting on the body, is in the direction of the net force, and is inversely proportional to the mass m of the body, i.e., F = ma. \item Third law: When two bodies interact by exerting force on each other, these forces (termed the action and the reaction) are equal in magnitude, but opposite in direction. \end{enumerate} \subsection{Newton's law of universal gravitation} Newton's law of universal gravitation states that the gravitational force between two bodies of mass $m$ and $M$ separated by a distance $r$ is $$F=-G\frac{mM}{r^2}$$. \subsection{The MASS} The term ``mass' was introduced into mechanics by Newton in 1687 in his ``Principia''. There are the following properties of mass in Newtonian mechanics: \begin{itemize} \item Mass is a measure of the amount of matter. \item Mass of a body is a measure of its inertia. \item Masses of bodies are sources of their gravitational attraction to each other. \item Mass of a composite body is equal to the sum of masses of the bodies that constitute it; mathematically that means that mass is additive. \item Mass of an isolated body or isolated system of bodies is conserved: it does not change with time. \item Mass of a body does not change in the transition from one reference frame to another. \end{itemize} \subsection{The amount of matter} \label{subsec:mylabel1} Newton defined mass as the amount of matter. Macroscopically, mass is associated with matter. the mass of an object is somehow relate with the number and type of atoms or molecules it contains, and with the energy involved in binding it together (which contributes a negative "missing mass," or mass deficit). But matter, unlike mass, is poorly defined in science. The generally accepted definition of matter does not exist even today. This is partially because there are so many different kinds of matters with quite different properties. \subsubsection{Can matter have zero mass?} Some may claim that matter is anything that occupies space and has rest mass. Under this definition one will not consider photons -- particles of light -- as particles of matter, because they are massless. For the same reason they do not consider as matter the electromagnetic field. It is not quite clear whether they consider as matter almost massless neutrinos, which usually move with velocity close to that of light. %Of course it is %impossible to collect a handful of neutrinos similarly to a handful of %coins. But in many other respects both photons and neutrinos behave like %classical particles, while the electromagnetic field is the basis of our %understanding of the structure of atoms. On the other hand, the so-called %weak bosons $W^+$, $W^-$, $Z^0$ are often not considered as particles of %matter because they are too heavy and too short-lived. % %Even more unusual are such particles as gluons and quarks. Unlike atoms, %nucleons, and leptons, they do not exist in a free state: they are %permanently confined inside nucleons and other hadrons. \subsubsection{We only known so little about matter} Even more strangely, the ordinary matter, in the quarks and leptons definition, constitutes about 4{\%} of the energy of the observable universe. The remaining energy is theorized to be due to exotic forms, of which 23{\%} is dark matter and 73{\%} is dark energy. We have very little knowledge about the majority matter of the universe. Anyway roughly speaking, the mass is somehow the measure of amount of matter. \subsection{The inertia mass} Inertial mass is a measure of an object's resistance to changing its state of motion when a force is applied, which arises naturally from Newton's second law of motion. It is determined by applying a force to an object and measuring the acceleration that results from that force. An object with small inertial mass will accelerate more than an object with large inertial mass when acted upon by the same force. One says the body of greater mass has greater inertia. \subsection{How to measure the inertia} We can measure its acceleration (assuming only that we can readily measure length and time) and hence the force acting on it in terms of its mass. The relation between mass and force is given by$\vec {F}=m_i \ddot {\vec {r}}$. %Although it is quite usual to refer to the scalar coefficient $m$ in this %relation as the mass, strictly speaking, what we detect when we apply a %force to a body is its inertia. For any arbitrary body, the inertial mass is defined as follows: we take the body and let it interact, somehow, with a standard inertial mass (one kilogram). Both the body and the standard will accelerate towards or away from one another. Designating the acceleration of the body and of the standard by $a_{ }$and $a_s $, respectively, we can define the inertial mass by \ \subsection{The gravitational mass} The gravitational mass can be described as a measure of magnitude of the gravitational force which is \begin{itemize} \item exerted by an object (active gravitational mass), and \item experienced by an object (passive gravitational force) \end{itemize} when interacting with a second object. Newton's law of universal gravitation states that the gravitational force between two bodies of mass $m_G$ and $M_G$ separated by a distance $r$ is $$F=-G\frac{m_G M_G}{r^2}.$$ \subsection{How to measure the gravitational mass} The gravitational mass can be defined in a similar manner. We take a standard object and define its gravitational mass to be one unit; for convenience we will use the standard kilogram as a standard for both inertial and gravitational mass. We now place the body at some distance $r$ and let it interact gravitationally with the standard. The body will accelerate towards the standard. We define the gravitational mass of the body in terms of this acceleration and the distance between the objects: \ Alternatively, using $m_i =\frac{a_s }{a}$ we can write this as \ This gives the gravitational mass in kilograms. The limiting procedure $r\to \infty $ is needed in order to eliminate the effects of multipole fields, which depend on the mass distribution of the two bodies. Also, proceeding to the limit $r\to \infty $ eliminates the effect of shorter range forces (nuclear force, Van der Waals force etc.). At large distances only the gravitational and electrostatic forces will remain, but the latter can be eliminated by taking the precaution of keeping the standard body neutral. If we take two identical copies of the standard mass and let them fall towards each other, the acceleration of each serves to define the constant $G$: \ \subsection{Put together} With these precise definitions of $m_i $ and $m_G $ it is clear that the gravitational force between two particles is \ and the equation of motion is \ \subsection{Two conceputure differnet mass} Whether all particles fall in the gravitational field of the particle of mass $M_G $ with the same acceleration depends on whether all particles have the same value of $$\frac{m_i }{m_G }$$ If this ratio is a universal constant, it must have the value one (the standard body has this value by definition). The question is then, is the equation \ satisfied for all bodies? This is a question which can be answered only by experimental means. \subsection{The additive of mass} In Newtonian Mechanics, mass of a composite body is equal to the sum of masses of the bodies that constitute it; mathematically that means that mass is additive. Together with the believe that matter cannot be destroyed or eliminated, the mass is believe to be always a positive real number. \subsection{Mass is conserved quantity} Mass of an isolated body or isolated system of bodies is conserved: it does not change with time. This is the reflection of the believe that matter cannot be destroyed or created. Things will not be so obviously in relativity. \subsection{Mass is invariant} Mass of a body does not change in the transition from one inertial reference frame to another in Newtonian Mechanics. Things will not be so obviously in relativity. \section{Mass in Lagrangian Mechanics} \subsection{Elementary Introduction of Lagrangian Dynamics} Let's consider the Newton equation \ in the one-dimensional case, in which all the physical parameters depend on the variable $x$only. Assume that the \emph{force is conservative}, which means that it is given as the spatial derivative of the \textbf{potential energy} $U(x)$: \ Thus for this case Newton's equation can be re-written as \begin{equation} \label{eq1} m\ddot {x}=-\frac{dU}{dx}, \end{equation} where $ \dot {x}=\frac{dx}{dt}=\mbox{v} $ and $ \ddot {x}=\frac{d^2x}{dt^2}=a. $ Define the \textbf{Lagrangian} $L\left( {x,\dot {x}} \right)$as a function of two variables, the position $x$ and the speed $\dot {x}$, \begin{equation} \label{eq2} L\left( {x,\dot {x}} \right)=T\left( {\dot {x}} \right)-U\left( x \right)=\frac{1}{2}m\dot {x}^2-U\left( x \right), \end{equation} \begin{itemize} \item the kinetic energy $T\left( {\dot {x}} \right)=\frac{1}{2}m\dot {x}^2$ is a function of the speed variable only, \item and the potential energy is a function of the position only. \end{itemize} \subsubsection{The Euler-Lagrange equation} From Eq. (\ref{eq2}) one can easily see that \begin{equation} \label{eq3} \frac{\partial L}{\partial x}=-\frac{dU}{dx}, \quad \frac{\partial L}{\partial \dot {x}}=m\dot {x}=p. \end{equation} Then obviously \begin{equation} \label{eq4} \frac{d}{dt}\left( {\frac{\partial L}{\partial \dot {x}}} \right)=m\ddot {x}. \end{equation} With the use of Eq. (\ref{eq3}) Newton's Eq. (\ref{eq1}) becomes \ which is called \textbf{the Euler-Lagrange equation} in one dimension. \subsubsection{The Hamiltonian formulation} To find the Hamiltonian formulation of dynamics, we define first the Hamiltonian $H\left( {x,p} \right)$ as a function of two new variables, the momentum $p$ and the position $x$: $ H\left( {x,p} \right)=p\dot {x}-L\left( {x,\dot {x}} \right), $ which is just the total energy $T+U$ as \begin{equation} \label{eq5} H\left( {x,p} \right)=p\dot {x}-L\left( {x,\dot {x}} \right)=m\dot {x}^2-\left( {\frac{1}{2}m\dot {x}^2-U(x)} \right)=T+U. \end{equation} The Hamilton equations, which replace Newton's equation of motion Eq. (\ref{eq1}) are given by \begin{equation} \label{eq6} \dot {x}=\frac{\partial H}{\partial p},\dot {p}=-\frac{\partial H}{\partial x}. \end{equation} %\subsection{The principle of least action} \subsubsection{Two ways to look at the physical motion} One way to understand physical motion is through differential equations, which describe how physical quantities change continuously with time. If we known the position and momentum for this moment, we can calculate from the equation how the object will move in the next moment. There is an alternative approach to look at this. Supposed that there are infinite mathematically possible paths for a system. The task for physic law is to find out which one is the real path nature takes. It's interesting that the real path actually followed by a physical system is always that for which make some quantity minimized, or, more strictly, is stationary. %That is to say, the action satisfies a variational principle: the principle %of stationary action. The action is defined by an integral, %and the classical equations of motion of a system can be derived from %minimizing the value of the action integral. \subsubsection{The principle of least action} The formal definition of the principle of least action is that it is "the principle stating that the actual motion of a conservative dynamical system between two points takes place in such a way that a function of the coordinates and velocities, called the action, has a minimum value with reference to all other paths between the points which correspond to the same energy." \subsubsection{The action} In physics, action is an attribute of the dynamics of a physical system. It is a mathematical functional which takes the trajectory, also called path or history, of the system as its argument and has a real number as its result. Generally, the action takes different values for different paths The action $S$ of a system, which is a scalar quantity, is defined as the time integral of the Lagrangian function, \ Therefore the problem of the motion of a mechanical system can be stated as that of finding the path $x(t),t_1 \le t\le t_2 ,$ such that the action $S$ is minimal. From a mathematical point of view this class of problems belongs to the field of mathematics called variational calculus and a quantity defined like the action is named functional.~A functional will have its extremal value when its "variation" is equal to zero.~ (This is like a function having an extremal value when its derivative is equal to zero). Consider two points $A$ and$B$. There are many trajectories joining the points, but a mechanical system which is evolving between them is choosing the trajectory that makes the action functional extremal. Let's assume that $x(t)$is the real trajectory of the body. Let's us also imagine a second trajectory, which is very near to the first, given by $x(t)+\varepsilon h(t)$, where $h(t)$ is an arbitrary time dependent function and $\varepsilon $ is a constant satisfying the condition $\varepsilon 1$. Obviously at the ends of all varied paths $h(t)$ satisfies the conditions \begin{equation} \label{eq7} h\left( {t_1 } \right)=h\left( {t_2 } \right)=0. \end{equation} The value of the action integral, which is a scalar, will be necessarily different according to the path taken by the particle to go from $A$ to$B$, \ \ne S\left . \] To find the curve or curves and the path or paths that make the action extremal, we shall use the variation of the trajectory and evaluate the action for the extremal and for the varied trajectory. For the Lagrangian along the varied path we obtain, by using a Taylor series expansion, \ Therefore the variation of the action along the two paths is given by \ -S\left =\varepsilon \int_{t_1 }^{t_2 } {\left( {\frac{\partial L}{\partial x}h+\frac{\partial L}{\partial \dot {x}}\dot {h}} \right)dt} . \] The second term in the integrand can be transformed by using partial integration, \ _{t_1 }^{t_2 } -\int_{t_1 }^{t_2 } {\left( {\frac{d}{dt}\frac{\partial L}{\partial \dot {x}}} \right)h(t)dt=-\int_{t_1 }^{t_2 } {\left( {\frac{d}{dt}\frac{\partial L}{\partial \dot {x}}} \right)h(t)dt} } , \] since $h\left( {t_1 } \right)=h\left( {t_2 } \right)=0.$ Then the variation of the action integral for a very small $\varepsilon $ is \ -S\left }{\varepsilon }=\int_{t_1 }^{t_2 } {\left( {\frac{\partial L}{\partial x}-\frac{d}{dt}\frac{\partial L}{\partial \dot {x}}} \right)h(t)dt} . \] Since $h(t)\ne 0$for $t_1 tt_2 $, for the path $x(t)$followed by the particle between the two fixed points $A$and $B$be an extremal of the action$S$, it is necessary and sufficient that the quantity between the brackets in the integral be zero. Then this condition gives the Euler-Lagrange Equations: \ \subsection{All are in Lagrangian} Therefore the equation of motion of a particle under the action of a conservative force can be derived from the Principle of the Least Action. So all information about the dynamics of the system is contained in the $$L\left( {x,\dot {x}} \right)=T\left( {\dot {x}} \right)-U\left( x \right)=\frac{1}{2}m\dot {x}^2-U\left( x \right)$$ \subsection{Why such Lagrangian?} Lagrangian of free particle can be determined by space-time symmetries. In the above, we find the Lagrangian from the newton's law of motion. Also in reverse, if we known the right Lagrangian, we could derive the equation of motion through the Euler-Lagrange Equations. If we want do it in reverse, how could we find the right Lagrangian? One might wonder whether one must simply guess at the form of the Lagrangian, such as the choice $\dot {x}^2$ , or if there is a more basic principle for finding the right Lagrangian. \subsection{Symmetry is fearful!} One way of doing so, is by thinking the symmetry of space-time. \\~\\ \textbf{The remarkable thing is that certain symmetries are so powerful and so restrictive that they entirely determine the functional form of the Lagrangian, and therefore the equations of motion.} \subsection{Newtonian picture of the world} The very least we can say about our world according to Newtonian mechanics is: the Universe is made of particles, space and time. The positions of particles change with time, according to Newton's law of motion. In other words, we try to describe the Lagrangian as a function of position x, time t and velocity $\dot {x}\mbox{=}\frac{dx}{dt}$ . \textbf{The basic assumption about the Lagrangian of Newtonian mechanics} is then it has the form$$L_{{\kern 1pt}0} \left( {{\rm {\bf x}},{\rm {\bf \dot {x}}},t} \right)$$. \subsection{Properties of Lagrangian} The choice of a least action principle as the basis of a theory of dynamics immediately implies that the Lagrangian has certain properties. First, we get the same equations of motion if we multiply that function with an arbitrary constant. Second, we get the same motion if we add to the integrand the total time derivative of an arbitrary function of space-time: $${L}'\mbox{=}L+\frac{df\mbox{(x,t)}}{dt}$$ then $${S}'=\int {{L}'dt} \mbox{=}\int {Ldt} +\int {\frac{df\mbox{(x,t)}}{dt}dt} \mbox{=}S+f_B \mbox{-}f_A $$ The additional terms are fixed, so that they have no influence on the equations of motion. The above two properties of $L$ are mathematical consequences of our decision to use a least action principle. \subsection{Create Lagrangian from Symmetry principle} But further restrictions on $L$ must be built in by using clues from Nature. These may be of any kind, but in practice the most powerful and general have proven to be symmetries of space-time. To begin with, consider the general form Lagrangian of a free particle$$L_{0} \left( {{\rm {\bf x}},{\rm {\bf \dot {x}}},t} \right)$$. \subsubsection{Invariance under Spatial and Time Translations:} The first symmetry is the \textbf{\textit{homogeneity of space and time}}. That is to say, the motion of a free particle does not depend on the place from which we measure its progress, nor does it depend on the time at which we start our measurement. Accordingly, $L_0$ cannot explicitly depend on $\bf x$ or $t$, so that $$L_{{\kern 1pt}0} \left( {{\rm {\bf x}},{\rm {\bf \dot {x}}},t} \right)\mbox{=}L_{{\kern 1pt}0} \left( {{\rm {\bf \dot {x}}}} \right)$$ \subsubsection{Invariance under Spatial Rotations:} The second symmetry is that of \textit{the isotropy of space}. That is to say, the motion of a free particle does not depend on the orientation of our coordinate system. We conclude immediately that this means that $L_{0}$ cannot depend on the direction of${\rm {\bf \dot {x}}}$, but only depend on the magnitude. It must be invariant under any rotations:$$L_{{\kern 1pt}0} \left( {{\rm {\bf R}}{\kern 1pt}{\rm {\bf \dot {x}}}} \right)=L_{{\kern 1pt}0} \left( {{\rm {\bf \dot {x}}}} \right)=L_{{\kern 1pt}0} \left( {\left| {{\rm {\bf \dot {x}}}} \right|} \right)$$ where \textbf{R} is a rotation operator and $\left| {{\rm {\bf \dot {x}}}} \right|=\sqrt {{\rm {\bf \dot {x}}}\cdot {\rm {\bf \dot {x}}}} $ \subsubsection{Invariance under Galilean Transformations:} There is yet another symmetry essential to the Newtonian mechanics: Galilean relativity. Coordinates of $S$ and $S'$, moving with relative velocity \textbf{v}, are related by $\mathbf{x}'=\mathbf{x}-\mathbf{v}t $ and $t'=t$ If $S$ is an inertial system in which Newton's 1$^{st}$ law holds, so is $S'$. \textbf{Physics law should be invariant under Galilean transformations, so does the Lagrangian.} How will this symmetry restrict the form of Lagrangian? We will see through the following trick. We denote $X=\frac{1}{2}\left| {{\rm {\bf \dot {x}}}} \right|^2$, using this new variable to express the free particle with Lagrangian $L_{{\kern 1pt}0} \left( {\left| {{\rm {\bf \dot {x}}}} \right|} \right)=L_{{\kern 1pt}0} \left( X \right)$. Thus the Euler-Lagrange equations are $$0=\frac{d}{d{\kern 1pt}t}\left( {\frac{\partial {\kern 1pt}L_{{\kern 1pt}0} }{\partial {\kern 1pt}{\rm {\bf \dot {x}}}}} \right) =\frac{d}{d{\kern 1pt}t}\left( {\frac{\partial {\kern 1pt}X}{\partial {\kern 1pt}{\rm {\bf \dot {x}}}}\frac{d{\kern 1pt}L_{{\kern 1pt}0} }{d{\kern 1pt}X}} \right) =\frac{d}{d{\kern 1pt}t}\left( {{\rm {\bf \dot {x}}}\frac{d{\kern 1pt}L_{{\kern 1pt}0} }{d{\kern 1pt}X}} \right)$$ where $\frac{\partial {\kern 1pt}X}{\partial {\kern 1pt}{\rm {\bf \dot {x}}}}=\frac{\partial }{\partial {\kern 1pt}{\rm {\bf \dot {x}}}}\left( {\frac{1}{2}{\rm {\bf \dot {x}}}\cdot {\rm {\bf \dot {x}}}} \right)={\rm {\bf \dot {x}}}$ \ \ \ Under the Galilean transformation \ \ The Euler-Lagrange equation can remain unchanged iff $$\frac{d^2L_{{\kern 1pt}0} }{d{\kern 1pt}X^2}=0$$ which imply that $$\frac{d{\kern 1pt}L_{{\kern 1pt}0} }{d{\kern 1pt}X}=const\equiv m$$ So $$L_{{\kern 1pt}0} =\frac{1}{2}m{\kern 1pt}\;{\rm {\bf \dot {x}}}^2+const$$ And the mass is nothing but just a integral constant in the Lagrangian. \subsection{Symmetry determine the dynamic} The conclusion is that Lagrangian of free particle is determined by spacetime symmetries. Note that the above mechanism of using symmetries to nail down the functional form of $L$ works wonderfully in other cases, too. In fact, all known forces of Nature can be derived from a symmetry principle which, remarkably enough, not only prescribes the Lagrangian of a free particle (like the way in which we obtained above), but the interactions as well. \section{Summary: what is mass then?} \begin{itemize} \item a quantitative measure of an object's resistance to acceleration \item or a measure of magnitude of the gravitational force \item or just a parameter in the Lagrangian? \item ...even stranger in the next lecture...coming soon... \end{itemize}
通常，一份英文的研究计划大约1~2千字，虽然没有明文规定的要求，但是还是建议大家考虑以下几点： A typical research proposal will be somewhere between one and two thousand words. While we do not insist on a definite format, we encourage students to keep the following in mind: The proposal should begin by explaining the subject area in which the research is to be located, and providing an indication of the key theoretical, policy or empirical debates it plans to address. The proposal should then present a brief review of the literature you plan to contribute to in conducting your own research. You need to demonstrate a familiarity with the relevant academic literature and theories relating to your research proposal, and an awareness of the major lines of argument that have been developed in your chosen research field. You then need to discuss the research questions you plan to address. Importantly, you need to demonstrate the manner in which your research questions emanate from: gaps in the existing empirical literature; from the application of a particular theory in a specific industry or national context; or from a synthesis of a number of bodies of literature, for example. Although not essential, research questions that are topical or have policy relevance will be particularly welcome. You research proposal should be as specific and focused as possible. If your research is being driven by gaps in the existing literature, which of these gaps will you attempt to address? If your research is being driven by theoretical or policy debates, which specific points of these debates are you going to focus on? The research proposal can also provide some explanation of what led you to the topic. Thus, if your topic emerges from a long-standing interest or from interests you developed while studying for a former qualification, do not hesitate to impart this information - it will help to convey your motivation for pursuing doctoral studies. Depending on the nature of your subject, it is desirable to give some indication of the research methods that will be used to conduct the research. A variety of different research methods exists, so you should seek to identify the method that is most suited to your area of research - econometric modelling, participant observation, survey data analysis, case-study analysis, the analysis of historical records, for example. Most doctoral work involves empirical research. The successful completion of doctoral work in the time allotted thus often depends on the ability to obtain the data needed. If your proposed research involves empirical work you should provide an indication of how you might collect any relevant data. For example, you might like to say something about access to particular sources of information (whether you will need on-line access to databases, whether you can use relevant archives etc). You could also comment on the country or geographical region in which the study will take place and explain why you have chosen this country/ region. It might also be worth saying something about unit of analysis for the research (whether you are looking at individuals, groups, workplaces, companies etc) and provide some justification for your choice of unit of analysis. Importantly, you need to explain the manner in which the data you collect will enable you to address your research questions. You should give special attention to the feasibility of data collection. Your proposal may contain interesting and highly relevant research questions, and it may be well grounded in the literature, but it may not be a practical research enterprise. You must balance the scope of your proposal against the practical problems of data gathering. Does your research proposal call for special access to managers or organisations? How many potential variables or factors does it require you to address? Can you examine all of them? Students whose projects involve data gathering in countries other than the UK are advised to pay close attention to the issue of feasibility. Students whose projects depend on data that are not available in the UK should indicate in their proposal how they propose to finance their data gathering. Although no indication of the research findings can be presented, it is often beneficial to conclude the research proposal by indicating the contribution you envisage that your research will make to the literature in your particular subject area, or by indicating the potential practical or policy implications of your research. This means providing an indication of the extent to which you feel your research will make an original contribution, suggesting how it may fill gaps in existing research, and showing how it may extend understanding of particular topics. While your research proposal is judged mainly on content, it must also look professional. It should be typed and written in good English. If you are submitting a photocopy, make sure it is of the highest quality. Particular attention will be paid to clarity of expression and also the structure, coherence and flow of argument. Finally, always include a bibliography (in a standard format – e.g. Harvard) with your research proposal that lists books and articles to which you make reference in your proposal. Finally, it is natural for ideas to evolve and change, so you will not be obliged to adhere to the specifics of your proposal if you are offered a place on the programme. However, the proposal is the foundation of your working relationship with your supervisors and thus it cannot be radically altered without discussion and consultation with your supervisors. 【参考资料】 http://www.education.monash.edu.au/students/current/study-resources/proposalwriting.html http://www.ssdd.bcu.ac.uk/learner/writingguides/1.07.htm http://www.geog.ox.ac.uk/graduate/apply/research_proposal.html
There are only two seasons in NC（short for NanChang）. one is summer，the other is winter. and this time i would like to talk about summer.which i am suffering . it impresses me not only the hot weather. besides that， there are something else. what are they？ Changeable weather . it maybe sunny in the morning，raining in the afternoon，colding in the evening. you could experience different seasons in a day or even just some hours. you nerve got to know what is happening next and what is prepared for you. maybe you think it is a good day for going out. be careful about that. something bad are around the corner. never go out without fully prepared and planned. Long period . the summer of NC may start from may， end at october . it lasts more than six months. in fact，it kills the autumn. that is why we don't have autumn in NC. sometimes i would complaint about the long time. and wonder howlife here survival from long period of so hot wether. are they special？ Water shortless . i mean in my dormitory. water suppling is sometimes going wrong. during that time. i feelvery misery and how valuable the water is ，how hard our life is. and my daily life goes in a mess. the WC is dirty and full of bad smell. i can't take a comfortable bath and enjoy the colding feeling. i wake up a lot of times during the short night. i am sleepless. it is the nightmare of me. the biggest pain is not the death of your best loving， it is without water ！ To summer up . living in NC is not that easy aswe think，especially in the summer. those who are survivaling here is not onlyneed a strong heart. a good health. besides that ， we eagerly neednon-stopped suppling offresh water！
http://www.huffingtonpost.com/2012/04/19/dark-matter-sun-gravity_n_1438425.html By: Charles Q. Choi Published: 04/19/2012 10:00 AM EDT on SPACE.com A new study has found no trace of the mysterious substance known as dark matter around the sun, adding a twist to current theories, researchers say. Dark matter is one of the greatest cosmic mysteries of our time — an invisible, intangible material thought to make up five-sixths of all matter in the universe. Scientists currently think it is composed of a new type of particle, one that interacts normally with gravity but only very weakly with all the other known forces of the universe. As such, dark matter is detectable only via the gravitational pull it generates. Astronomers first proposed the existence of dark matter to explain why stars moved the way they did in the Milky Way. It was as if extra matter was present, exerting a gravitational pull that influenced the motions of the stars. According to widely accepted theories, the neighborhood around the sun should be filled with dark matter, with billions of these particles rushing through us every second. However, the most accurate study yet of motions of stars in the Milky Way now has found no evidence for dark matter in a large volume around the sun. "Our results contradict the currently accepted models — the mystery of dark matter has just become even more mysterious," said study lead author Christian Moni Bidin, an astronomer at the University of Concepción in Chile. Hunting dark matter The scientists used telescopes at the La Silla Observatory and the Las Campanas Observatory, both in Chile, to map the motions of more than 400 red giant stars up to 13,000 light-years from the sun. This helped calculate the mass of material in the vicinity of the sun, in a volume four times larger than ever considered before. "The amount of mass that we derive matches very well with what we see — stars, dust and gas — in the region around the sun," Moni Bidin said. "But this leaves no room for the extra material — dark matter — that we were expecting. Our calculations show that it should have shown up very clearly in our measurements. But it was just not there!" Dark matter models had predicted there should be about 0.9 to 2.2 pounds (0.4 to 1 kilograms) of dark matter in a volume the size of the Earth in the sun's part of the galaxy. However, these new findings suggest there is at most 0.15 pounds (70 grams) of dark matter in that volume in our part of the Milky Way galaxy . "Despite the new results, the Milky Way certainly rotates much faster than the visible matter alone can account for, so if dark matter is not present where we expected it, a new solution for the missing mass problem must be found," Moni Bidin said. Dark matter's elusiveness explained? The findings could explain why all attempts to detect dark matter in laboratories on Earth have failed so far — there is much less of it in the sun's neighborhood than expected. "Strictly speaking, the results do not say that dark matter does not exist — they only say it is not here," Moni Bidin told SPACE.com. "We have not proven that dark matter does not exist, and even if we do, at this point we cannot explain many other phenomena that today are explained only by dark matter." One alternative to dark matter is known as Modified Newtonian Dynamics, or MOND, which tweaks how gravity works at large scales to help explain the motions of stars and galaxies that researchers observe. However, "to my knowledge, MOND also would have expected a massive 'phantom disk' to appear in our study, so our results should contradict its expectations, too," Moni Bidin said. Future astronomical surveys, such as the European Space Agency's Gaia mission, could help shed further light on dark matter, Moni Bidin said. Gaia will collect data to reconstruct the movement of millions of stars. "Thus, we will be able to test the presence of dark matter in a wide region of the galaxy," he explained. The scientists will detail their findings in a future issue of the Astrophysical Journal.
After a few rainy days, it is a beatiful day today. I did not get to know it by going around my campus butby telling from the sunlight through our office window. Actually, I worked all day long infront of my computer without taking a lunch break because I have encountered a problem in combing base classifiers.There are three base classifiers and when I adopt the majority voting method, each classifier may get equal votes. Under this circumstance, how can I know wichclass is right or is the mostly accurate class?
Abstract Inflammation is a protective attempt by the organism to remove the injurious stimuli and to initiate the healing process. Initiation and progression of inflammation involves a complex cellular network, the predominant innate immune cell in inflammation is the monocyte-macrophage.The behavior of this cell type within the inflammation is heterogeneous and depends on the recruitment of diverse monocyte subsets.Recent efforts to elucidate the local tissue microenvironment offers polarization and activation signals which impact on macrophage phenotype . In this paper, we review the literature addressing the tissue factor in modulating macrophage heterogeneity and activation with adipose tissue, central nervous system ,aging. Key words : inflammation,tissue factor,macrophage heterogeneity and activation, adipose tissue,central nervous system Introduction Tissue macrophages have a broad role in the maintenance host defence,immunity, homeostasis, and act through several mechanisms by destroying bacteria,parasites, viruses and turmor cells,clearing necrotic debris ,apoptotic and senescent cells,processing antigens and presenting digested peptides to adoptive immunity, remodeling and repairing tissue damage(1,2, Jorge Lloberas et al.,2002,to cites or not to cited,not to cited at best) . M acrophage s undertaken so diverse burdens are tightly connected with their multiple characters.It has been known for decades that cytokines can alter macrophage functional responses( 1,3,4 i n Ro bert D.Stout et al.,2 005).Distinct functional phenotypes subsequently were reported to be generated by stimulating macrophages with a variety of agents,including IFN-r,IL-4,IL-10,TGFbeta( 4,5- 9).In addition,macrophages can reversibly and progressively shift their functional phenotype through a multitude of patterns in response to changes in microenvironmental influences( Ro bert D.Stout et al.,2 005). Macrophages are highly heterogeneous cells(10-12) that are able to respond to the specialization function of anatomical sites in tissues, primarily reflecting their local metabolic and immune microenvironment(Siamon Gordon et al.,2005). Such as in central nerve system , macrophages differ in cytoskeletal functions and migration towards specific CNS cell types under a variety of environmental cues (Elly JF Vereyken et al.,2011).High fat feeding- induced obesity leads to a phenotypic shift of adipose tissue macrophage(ATM) from an M2-polarized state that may protect aidpocytes from inflammation to an M1 proinflammatory state(Carey N.Lumeng et al.,2007, Justin I. Odegaard and Roberto R. Ricardo-Gonzalez et al.,2007) Aging associated malfunction of macrophages has contributed to a decline in the functional activity of the immune system(Jorge Lloberas et al.,2002, Julie Plowden et al.,2004 ). Th ese examples indicate that the tissue microenvironment can markedly influence the phenotype of tissue-resident macrophages (13) . Macrophages are a key cell component of the inflammatory reactions expressed at various pathological sites. Understanding the pathogenetic role played by polarized functions may pave the way for the identification of novel therapeutic approaches Macrophage activation and heterogeneity in inflammation (The spectrum of macrophage:macrophage population,Roles of macrophage in inflammation,2007) In response to cellular differentiation ,wide-spread tissue distribution and many endogenous and exogenous stimuli, Macrophages show significant heterogeneity in function(??14,15??)(14, 16). Different stimuli activate macrophages to express distinct patterns of chemokines, surface markers, and metabolic enzymes that ultimately generate the diversity of macrophage function seen in inflammatory and noninflammatory settings. Macrophage activation has been operationally defined across 2 separate activation status: interferon-r(IFN-r) mediated classically activated (CA/M1),pro-inflammatory, macrophages.Alternatively activated (AA/M2), growth promoting,macrophages, induced by the T helper 2(Th2) cytokines interleukin-4 and IL-13 (17,18) . These states have largely been defined in vitro, and tissue macrophages are likely activated along a continuum between these states in vivo(19,20,in Carey N.Lumeng et al.,2007).Mosser et al depict the spectrum showing the linear scale of the two macrophage designations.They propose three populations of macrophages based on their fundamental functions.(1) Classically activated macrophages,are vital components of host defence,predispose to cause host-tissue damage,autoimmune diseases.(2) Wound-healing macrophages,promote the production of extracellular matrix contributing to tissue repair and homeostasis,lead to fibrosis,exacerbate allergic responses.(3)Regulatory macrophages,dampen the immune response and limit inflammation,dysregulated action can contribute to the progression of neoplasia(Mosser and Edwards et al.,2008).Subsequently,Gordon et al argue that the definition on “alternative”form of activation is too loose in macrophage study. For searching potential therapeutic targets,it is required to( ##restrict the previous nomenclature,and ##)take into account the complex effects of the IL-4 and IL-13 dependence combined with cell differentiation, interactions,and local tissue microenvironment in modulating the macrophage pattern(Gordon et al et al.,2010). Key role of adipose tissue in the inflammation response An important initiator of the inflammatory response to obesity is adipose tissue. Adipose tissue is not merely an organ designed to passively store excess calories. Mature adipocytes synthesize and secrete numerous enzymes, growth factors, cytokines,chemokines and hormones that are involved in diverse processes in the body including lipid homeostasis and modulation of inflammatory responses.Adipocytes secreted termed adipocytokines or adipokines (21–23),that are recurrently reported over 50 different adipokines( http://themedicalbiochemistrypage.org/home.html ) . ###Give a general summary of these adipokines in Table 1#### Researchers found adipose tissues are infiltrated with increased numbers of macrophages in obese mice and human vensus lean counterparts,In addition,the content of these macrophages is in line with the level of obesity (25,26,27,28). Recently,Jerrold Olefsky and Christopher Glass contributed a wonderful review to summarize how adipose tissue modulates macrophage to propagate inflammation.They told a very interesting possibility that tissue cytokines in blood may “leak ”into the circulaton and impair insulin sensitivity in distal tissues in an endocrine fashion(29–31;Jerrold and Christopher et al.,2010). They also present activated T cells can modify macrophages behavior and contributed to insulin resistance(32).Th1 lymphocytes may participate macrophage migration and activation to raise the classical activated state ((33,34).While T-reg lymphocytes(Tregs) exert a protective effect to inhihit proinflammatory macrophages for a decrease in adipose tissue T-reg content in obesity(35,36). Another paper with leptin-de fi cient ob/ob mice,they induced TGF- β -dependent CD4+ latency-associated peptide positive Tregs found compromised status in inflammation,and decreased CD11b+F4/80+ macrophages and TNF- α in adipose tissue (Yaron Ilan and Ruth Maron et al.,2010).Although this furtherly confirms the role of Treg cells contributed to modulate macrophage activaity directly,as well as through cytokines,the molecular mechanisms underlying their contact-dependent interactions are poorly defined still. Organize below in a new detailed table.(cited from websites:) Table of Adipose Tissue Hormones and Cytokines Adipose tissue produces and releases a vast array of protein signal s including ( growth factor s, cy tokine s, chem oki nes, acut e phase prote ins, comp lement-like fac tors, and adhes ion mole cules,shape this table to new one ). The Table below describes several of the adipocyte proteins in more detail with leptin, adiponectin, and resistin discussed in greater detail in the following sections. The proteins of the various signaling processes are listed below. Factor Principal Source Major Action adiponectin also called adipocyte complement factor 1q-related protein (ACRP30), and adipoQ adipocytes see below adipsin (also called complement factor D) adipocytes, liver, monocytes, macrophages rate limiting enzyme in complement activation apelin adipocytes, vascular stromal cells, heart levels increase with increased insulin, exerts positive hemodynamic effects, may regulate insulin resistance by facilitating expression of BAT uncoupling proteins (e.g. UCP1, thermogenein) chemerin adipocytes, liver modulates expression of adipocyte genes involved in glucose and lipid homeostasis such as GLUT4 and fatty acid synthase (FAS); potent anti-inflammatory effects on macrophages expressing the chemerin receptor (chemokine-like receptor-1, CMKLR1) C-reactive protein (CRP) hepatocytes, adipocytes is a member of the pentraxin family of calcium-dependent ligand binding proteins; assists complement interaction with foreign and damaged cells; enhances phagocytosis by macrophages; levels of expression regulated by circulating IL-6; modulates endothelial cell functions by inducing expression of various cell adhesion molecules, e.g. ICAM-1, VCAM-1, and selectins; induces MCP-1 expression in endothelium; attenuates NO production by downregulating NOS expression; increase expression and activity of PAI-1 IL-6 adipocytes, hepatocytes, activated Th2 cells, and antigen-presenting cells (APCs) acute phase response, B cell proliferation, thrombopoiesis, synergistic with IL-1 and TNF on T cells leptin predominantly adipocytes, mammary gland, intestine, muscle, placenta see below monocyte chemotactic protein-1 (MCP-1) leukocytes, adipocytes is a chemokine defined as CCL2 (C-C motif, ligand 2); recruits monocytes, T cells, and dendritic cells to sites of infection and tissue injury omentin visceral stromal vascular cells of omental adipose tissue the omentum is one of the peritoneal folds that connects the stomach to other abdominal tissues, enhances insulin-stimulated glucose transport, levels in the blood inversely correlated with obesity and insulin resistance plasminogen-activator inhibitor-1 (PAI-1) adipocytes, monocytes, placenta, platelets, endometrium see the Blood Coagulation page for more details resistin adipocytes, spleen, monocytes, macrophages, lung, kidney, bone marrow, placenta see below TNFα primarily activated macrophages, adipocytes induces expression of other autocrine growth factors, increases cellular responsiveness to growth factors and induces signaling pathways that lead to proliferation vaspin visceral and subcutaneous adipose tissue is a serine protease inhibitor, levels decrease with worsening diabetes, increase with obesity and impaired insulin sensitivity visfatin; also called pre-B cell-enhancing factor (PBEF); reported to be the extracellular version of the enzyme nicotinamide phosphoribosyltransferase (Nampt or eNampt), however, the original paper claiming this has been retracted visceral white adipose tissue conflicting results relative to insulin receptor binding but blocking insulin receptor signaling interferes with effects of eNampt; changes in eNampt activity occur during fasting and positively regulate the activity of the NAD + -dependent deacetylase SIRT1 leading to alterations in gene expression Central nervous system It is well-accepted that monocytes can replenish tissue-macrophage numbers,especially during inflammation. However, the origin of the cells involved in this process is unclear,because it’s very complicated to distinguish the relative importance between local expansion and recruitment of microglia progenitors from the bloodstream. Although Monocytes can enter the CNS to populate macrophages ( 37 , 38,Siamon Gordon et al.,2005 ).There are evidences suggest that maintenance and local expansion of microglia are solely dependent on the self-renewal of CNS resident cells( 19 : Ajmi B and Bennett JL et al.,2007). Macrophages are important mediators in bridging innate and acquired immunity during neuroinflammation.Which can shape their phenotype and physiology to adapt to the local tissue microenvironment (13,14,Lument et al.,2007). In tissues, the microenvironment of the macrophages is thought to determine the phenotype . In vitro , cytokines and other stimuli induce these activation phenotypes. Recently,Christine D Dijkstra and colleagues published a research article to describe the characteristics of these phenotypically different macrophages in the context of the CNS. Their experiments present classically activated(CA) and alternatively activated(AA) macrophages behave differently incubated with the conditional media of CNS cells. (show in table 2)###in addition,give a description shortly### Table 2:based on Elly JF Vereyken et al,.2011 summarize in detail,continue….. CA AA Control the low weight ( 10 kD) fraction of neuronal conditioned medium, attracted higher numbers by astrocyte- and oligodendrocyte conditioned medium. attracted Intrinsic motility Low(a) High(2a) adhesion to extracellular matrix molecules (ECM) enhanced activity of the GTPases RhoA and Rac (actin cytoskeleton ) greater expression of CR3/ MAC-1(Phagocytosis of myelin and neuronal fragments) increased Effect of aging on macrophages ( human macrophages AND on animal models) Macrophages originate in the bone marrow and migrate to body tissues through blood,and therefore,which generally provide a limited view of tissue macrophages.CD68 positive cells,the markers of macrophage population ,have a dramatic decrease observed in the bone marrow of elderly people(Ogawa et al.,2000). Cell lifespan can be regulated mainly by telomeres and telomerases (Iwama et al., 1998).Telomere length and activity serve as biological regulators of the limited division potential of human cells.While terminal differentiated cells do not express telomerase(Weng, 2001).In order to uncover the functional activities of macrophages,several experiments have been performed to check the capacity of these cells to produce cytokines or chemokines(Beharka et al.,2001; Gon et al., 1996; Roubenoff et al., 1998;O’Mahony et al., 1998; Sadeghi et al., 1999; Ahluwalia et al., 2001; Mariani et al., 2002).Unfortunately,these reports are very contradictory mutually.However,some other reports suggest a decrease expression of scavenger receptor and apolipoprotein E, low respiratory burst of monocytes and susceptibility to stress-induced apoptosis during aging (Alvarez and Santa Maria, 1996;Monti et al., 2000). Experiments on animal models show impaired TNF-a production, Norepinephrine-induced chemotaxis and transcription of IAb gene (Corsini et al., 1999; Ortega et al., 2000).Aged macrophages treated with IFN-g produce lower MHC class II gene IA Complex,and intracellular IA b protein and mRNA(Herrero et al., 2001).Whereas treated with LPS produce more TNF-a and prostaglandin I than those from young animals(Tang et al., 2000)These results suggest that aged macrophages don’t work normally as young,further studies to clearify the phenotypic alteration and disclose the key molecular mechanisms of macrophage in aging state are very appreciated. Concluding remarks Macrophages,Inflammation ,CAD.pdf
昨天我整了篇题为 “ JBC vs PLoS ONE: 鹿死谁手 ? ”的博文，引起了不少网友，尤其是 牛登科先生的关注和热议， 登科先生还专门写了一篇博文“ 编委会自己审稿，算不算peer review ”，由于我对登科先生的博文的不少观点有自己不同的看法，所以也专门写此博文以商榷，也非常欢迎感兴趣的网友发表自己的观点和看法。 登科先生（称其牛先生似乎确有歧义 ）的一个重要观点是：“ Plos one和BBRC的审稿规则是一样的。都是主编、编委自己决定一部分自己熟悉的稿件，可以直接接受，不熟悉的再外审“。对于是否真的“Plos one和BBRC的审稿规则是一样的”，让我们先用事实说话。 根据PLoS One官方网站关于“ Editorial and Peer-Review Process ”介绍，我们可以知道：正如登科先生提到的，95.8%的接受稿件经过了外审（原文为： Currently, of the articles that are ultimately accepted for publication, 95.8% were sent for review by external experts.）那么剩下的4.2%是怎么回事呢，这部份没有经过外审就接受的稿件是：“Around 4.2%* of articles are peer reviewed by the Academic Editors themselves (often in consultation with other members of the Editorial Board)（博主注：这个Editorial Board有上千人的规模） when they are sufficiently expert in the field to determine whether the paper meets the PLoS ONE criteria .”也就是说，PLoS One有极少数稿件（5%的接受稿件），由熟悉稿件内容的小同行—学术编辑来亲自审稿并常常征询Editorial Board其他同行的意见，这种情况和其他一般国际期刊没有什么区别，因为别的期刊也会有少量稿件由于正好是主编／副主编或学术编辑熟悉该研究领域，就直接自己审稿并拍板决定是否接受。这也符合国际期刊的惯例。 更重要的是，大多数国际期刊都是只邀请两位审稿人审稿（当然也有极个别的有多达８位 reviewer 的期刊），而 PLoS One ，则 “On average, ALL accepted articles have been reviewed by 2.9* experts (one Academic Editor and 1.9* external Peer Reviewers).” ，也就是说，平均而言，所有的接受稿件要被３位专家（一位学术编辑 +2 位外部审稿人）审稿，比一般期刊还要严格！。 下面我们再来看看BBRC是如何审稿的，根据BBRC 官方网站关于” Peer Review Policy ”的介绍，原文为：“BBRC is a rapid communications journal. As such, the decision to publish an article rests entirely with the handling Editor. Manuscripts are assigned to members of the Editorial Board based on expertise. This Editor may accept the manuscript as it is, send it to a colleague for review, or reject it. Requests for revisions are rare. Should the Editor request revisions, the manuscript will be treated as a new submission.” 简单的说，绝大多数稿件，直接就由members of the Editorial Board来直接审稿并拍板决定是否接受，尽管文中说也许会送外审，但是通过丁香园众多网友的投稿经验来看，送外审的几率非常之低，就算送外审的比例很高，不管哪种情况，关键是：１）“This Editor may accept the manuscript as it is＂；２）Requests for revisions are rare，也就是说：无需任何修改，直接接受发表。所以文章的质量难以保证，因为几乎任何投稿论文都会有或多或少的问题和毛病，同行评审则可将（至少是可能的）问题和毛病最大程度上减少（当然不大可能完全解决掉）。 我们知道，国际期刊的同行评审(Peer Review)模式已经创立有上百年的历史了，发展至今，也确实存在不少问题，其存废之争多年来一直在进行，为何现在全球绝大多数期刊都还采用这一方式？就是目前还没有一套更好的系统还取代它。 综上所述，事实说明： PLoS One和BBRC的审稿规则是截然不同的 。 另外，登科先生还在其博文中提到：“ BBRC和PLoS ONE的内部审稿模式，是将来很多中低档期刊的发展方向。”。据我了解，BBRC是国际期刊中唯一采用（几乎是完全采用）这种内部审稿模式的（如有网友知道别的期刊，请指出，让我也长长见识），别的期刊都不这么玩，所以， 我不认为内部审稿模式是“将来很多中低档期刊的发展方向” 。 另外 PLoS One 和 BBRC 这两种期刊还是都是自己显著特点的，对于 PLoS One 而言，就是正如 其网站上所言 ： “Publish all papers that are judged to be technically sound. Judgments about the importance of any particular paper are then made after publication by the readership (who are the most qualified to determine what is of interest to them).” 。也就是说正如牛先生所指出的， PLoS One 不管你文章的重要性，只要你能技术上自圆其说即可，文章的重要性交给发表后的读者来评判。这种评判稿件的标准和原则在全球科技期刊中开了先河（不知现在有无第二家？！）。 PLoS One 这一准则也使得该刊发表了一些一般期刊不愿发表或不屑发表的有些另类的文章，比较典型的例子有：我国学者去年首次获得搞笑诺贝尔（ Ig Nobel Prize ）的论文即发表在 PLoS One 上，标题为： “Fellatio by Fruit Bats Prolongs Copulation Time” （果蝠 口/交 延长交配时间） “ （详见我的丁香园博文： 特大号外：来自中国大陆的学者终获诺贝尔奖！！ ） 而 BBRC 的显著特点就一个字： “ 快 ” ，到底能有多快呢，其网站上说 “Authors of manuscripts can expect an accept or reject decision normally within 2 weeks of receipt.” 即：一般稿件，投稿后 2 个周内决定是否接受，当然也有更长时间的，最短的：丁香园上有网友报料其投稿从投到接受，只用了几个小时， BBRC 被视为是全球 SCI 期刊中决定投稿是否接受最快的期刊。当然，由于 BBRC 处理稿件速度快，接受后又不用修改，所以对语言要求很高（接受后就没有机会改了），语言不过关，就会直接退回，修改后如果再投，就算新的投稿了。由于 BBRC 快字当头，确实是急等论文毕业的研究生和急需论文晋升的科研人员的福音，由于其影响因子不算高（ 2-3 分），对文章的质量要求不太高（要求最多４个图，创新性要求也不高，当然高了的稿件也不会投 BBRC ） , 所以也可视为广大搞生命科学的研究生们练手园地。 另外感谢科学网编辑将我和牛先生的博文一并推荐到博客首页，我很欣赏编辑鼓励将两种不同观点的博文进行讨论的方式，这种 “ 百家争鸣 ” 的风格才更能体现 “ 科学 ” 网的科学性，但愿以后科学网能更少一些既不科学也不和谐的博文（比如今天博主 A 对博主 B 公开宣称绝交啦，明天博主 B 对博主 A 也如法炮制）。 最后，和牛登科先生开个玩笑：我的 “ 守业 ” 之名字和 “ 登科 ” 一比，顿然显得胸无大志，小家子气！ （文首图片来自网络，特向作者表示谢意。 王守业写于 2011 年 4 月 19 日，引文地址： http://blog.sciencenet.cn/home.php?mod=spaceuid=563591do=blogquickforward=1id=435130 )
IMAGE: Molecular geneticist Shiva Singh of the University of Western Ontario found no two people are alike, even if they're identical twins. Singh is studying the genetic determinants of schizophrenia. Click here for more information. 西安大略大学（University of Western Ontario）的一个最新研究表明：就像没有完全相同的雪花一样，没有两个人相同，即使他们是同卵双胞胎。分子遗传学家Shiva Singh与精神科医生Richard O'Reilly合作，借助同卵双胞胎，测定了精神分裂症的基因序列，这一研究发表在这个月的PLoS ONE上. Singh发现100万同卵双胞胎，只有其中一个患有精神分裂症。Singh说道：“精神分裂症的最典型的特征是它偶尔出现于家庭。例如，如果你的兄弟、姐妹、母亲或者父亲患有精神分裂症，你患病的几率就大大高于正常人群的1%，我们开始相信同卵双胞胎在遗传学上是相同的，因此，如果精神分裂症都归咎于基因，那么双胞胎中的一个患病，另外一个患病的几率就是100%，然而，多年的研究表明双胞胎患病的几率是50%。”这意味着双胞胎遗传学上既不完全相同，精神分裂症这一家族病也不是与遗传无关。 Singh和他的团队已经证明双胞胎遗传学上不相同。Singh发现不同个体间12%的DNA是不同的，“因此，如果精神分裂症由基因决定，那么同卵双胞胎只有一个患病的话，他们遗传图谱的差异应该与该病有关。随着我们发展和区分，他们的细胞被分开。更加重要的是，患病的细胞丢失或者获得了一些DNA。其基因组不稳定。” O'Reilly医生希望这一研究有助于更好地了解精神分裂症，以及改善该病的治疗。 O'Reilly医生说：“如果我们获得了该病的遗传检测手段，在当今难于诊断该病的情况下，可以更早的应用。” 英文相关报道 http://www.eurekalert.org/pub_releases/2011-03/uowo-rpn032811.php
应科学网的博友许文婕之邀，写下几行文字来说说我的博客标题图片。 2009年春假我和几个朋友驾车环游了美国中西部地区的几个州，途中在堪萨斯州境内Tallgrass Prairie National Preserve拍摄了这张照片。照片上的房子是一所学校，名字叫做LOWER FOX CREEK SCHOOL，建于1882年，为当地社区的孩子提供教育。全校最多的时候才有19个学生，最少只有1个学生。不过这个学校持续运行了很多年，直到1930年随着社区的变迁才关闭。其后几经易手，曾经被龙卷风损坏，也曾经被改造为储存干草的库房。1968年以后，一些民间机构举资按照1882年初建时的原貌修复了这间学校。到了1974年，这里被列入美国国家历史古迹名录（the National Register of Historic Places）。 这个学校的特点在于只有一件房子。在19世纪末期，中西部的州先后加入了联邦政府，这种一间房子的学校在美国中部地区很普遍，这是因为早期的美国移民从东海岸新英格兰地区向中西部地区迁移，在地广人稀的条件下，只得建立这种小小的学校，为孩子们提供交流和学习的机会。这样的学校逐渐形成了统一的模式，并拥有了一个名字：One Room Country School。有一些美国本土的社会学者、教育学者曾经深入研究探讨过其渊源、意义和重要的作用，例如反对奴隶制，推广宗教信仰等等。博主做为一个外国的外行人，不敢妄加评论，以免贻笑大方。 这种单间学校是美国中西部地区的教育发展史上的代表性标志。2004年美国发行了Iowa州的纪念Quarter,做为代表本周特色的图案设计就是One Room Country School，并且在图案中加注了Foundation in Education。 PS：在Lower Fox Creek School不远的地方，曾经还有一个Upper Fox Creek School，据说是更小的学校，现在已经不知所踪。
标签: One
