土壤持水量 Water holding capacity (WHC) is the ability of a soil to contain and to retain water. Dependent upon the factors, which determine hydraulic conductivity and permeability e.g., texture, organic matter, porosity, interconnectednessof pores and so on. The water is held in the spaces, or pores, between soil particles and in thin films surrounding those particles. It iscalculated by mass of (water contained in the saturated soil / mass of the saturated soil)*100 or water holding capacity (%) = (m (water in saturated soil) / m (saturated soil) ) * 100. Therefore it should be a fixed value during short time. 田间持水量 (Field water capacity) 田间持水量是在地下水位较低(毛管水不与地下水相连接)情况下，土壤所能保持的毛管悬着水的最大量，是植物有效水的上限。田间持水量是衡量土壤保水性能的重要指标，也是进行农田灌溉的重要参数。田间持水量的测定大多采用田间小区灌水法，当土壤排除重力水后，测定的土壤湿度即为田间持水量，其技术操作简介如下： 1 仪器及工具准备 测定前应准备好土壤水分快速测试仪(TSC-1型土壤水分快速测试仪)、土钻(长不小于60cm)、卷尺、草席、塑料布、铁锨、水表或水桶，如果测定地块附近没有水源，还要准备足够的水量等。 2 测定场地的选择 根据我县不同的区域，我们分别选择了代表南部二阴高寒山区的马坡乡、代表北部干旱山区的上花岔乡、代表中部川水地区的清水驿乡3个样地进行测定。 3 测定程序 3.1 测定场地的准备 在所测定的地段上量取面积为4m2(2m×2m)的平坦场地，拔掉杂草，稍加平整，周围做一道较结实的土埂，以便灌水。 3.2 灌水前土壤湿度的测定 在准备好的场地外1～1.50m处，根据应测定田间持水量的深度(0.60m)以内，取2个重复的土样测定土壤湿度，最后求出所有测量值的平均值。 3.3 灌水前土壤湿度的确定 用水分快速测试仪分别对两个重复采样点按0～10cm、10～20cm、20～40cm、40～60cm的4个土层深度进行测量，再取其各层次平均值为该地面测定样方每层的测量值。根据公式 θ0-60cm =(θ0-10cm+θ10-20cm +2θ20-40cm+2θ40-60cm )/6计算得出：马坡乡为17.30%、上花岔乡为8.58%、清水驿乡为10.82%。 3.4 灌水 根据公式Q=2(θ1-θ2 )×S×H／100计算灌水量。其中Q：灌水量，单位m3。θ1 ： 假设的所测深度土层中的平均田间持水量，用体积含水量表示，壤土一般取37.50%，以百分值表示。θ2 ： 灌水前所测深度的各层平均土壤湿度，以百分值表示。S：灌水场地面积，以平方米为单位。H：所要测定的深度，以米为单位。常数2：保证小区需水量的保证系数。经计算，马坡乡灌水量为0.97m3，清水驿乡灌水量为1.39m3，上花岔乡灌水量为1.28m3。 3.5 覆盖 所有水应在1天内分次灌完，为避免水流冲刷表土可先在小区内放一些蒿草(秸秆)或在地埂边放些塑料再灌水。当水分全部下渗后，再覆盖上草席和塑料布，以防止蒸发和降水落到小区内。 3.6 测定时间 灌水后当重力水下渗后，开始用土壤水分快速测试仪测定土壤湿度。壤土在灌水2～3d后开始第1次测定，每天取1次，每次取4个重复，4个重复测点不应靠近小区边缘。 3.7 确定田间持水量 每次测定后，逐层计算同一层前后2次测定的土壤湿度差值，若某层差值≤3%，则第2次测定值即为该层土壤的田间持水量，下次测定时该层土壤湿度可不测定。若同一层次前后2次测定值 ＞3%，则需继续测定，直到出现前后2次测定值之差 ≤3%时为止。在实际操作中， 一定要注意多测量几次，直到前后两次值出现比较稳定为止，不能因为头两三次之差小于3%就确定最后一次值为田间持水量。 空隙含水量 Water filled pore space (WFPS) is also known as degree of saturation; it is the volume of water present in the soil relative to total volume of pores. It is calculated as (percentage ofvolumewater content / percentage of soil pore space) * 100, or WFPS (%) =(percentage ofvolumewater content / percentage of soil pore space) * 100 = (m water / m dry soil ) * soil bulk density / (1 - soil bulk density / soil particle density) * 100. Normally soil particle density is assumed as 2.65 g/cm 3 . 参考: http://bettersoils.soilwater.com.au/module3/3_09.htm ogden_water_holding_capacity_exercise.pdf PDF File.pdf sept 18.pdf SOIL_water_holding_capacity_LAB.doc WFPS.pdf
2012年诺贝尔医学生物学奖终于出炉，花落John B. Gurdon和Shinya Yamanaka！ 斯德哥尔摩时间8日11时30分(北京时间8日17时30分)，由诺贝尔委员会宣布，英国发育生物学家John B. Gurdon和日本生物学家Shinya Yamanaka最终获得2012年诺贝尔生理医学奖。他们的研究主要为“体细胞可以经重编程后转化为可诱导的多能干细胞”领域。 John B. Gurdon教授 John B. Gurdon是英国核转移和基因克隆方面的先锋研究者；2009年与Shinya Yamanaka共同获得有“美国诺贝尔“之称的拉斯科奖（Lasker Award），以表彰他们在基础医学领域的研究发现。 Shinya Yamanaka教授 Shinya Yamanaka是日本京都大学再生医科学研究所教授，iPS细胞研究中心主任，专注于干细胞研究。2008年，曾获颁邵逸夫生命科学与医学奖。 John B. Gurdon和Shinya Yamanaka在“体细胞可以经重编程后转化为可诱导的多能干细胞”的研究发现最终赢得了诺贝尔医学生物学专家委员会的肯定与认可，共同成为2012年诺贝尔医学奖的获奖者。 最后，感谢John B. Gurdon和Shinya Yamanaka在生物医学领域做出的贡献。 JohnB.Gurdon因1962年的开创性工作而获奖，这一年他29岁。 Gurdon, J.B. (1962). The developmental capacity of nuclei taken from intestinal epithelium cells of feeding tadpoles. Journal of Embryology and Experimental Morphology 10:622-640. 唯一作者概要:GURDON JB 时间跨度=所有年份. 数据库=SCI-EXPANDED. 找到的结果数: 192 被引频次总计: 12270 去除自引的被引频次总计: 11362 施引文献: 7956 去除自引的施引文献: 7787 每项平均引用次数: 63.91 h-index: 66 每年出版的文献数 每年的引文数 http://apps.webofknowledge.com/CitationReport.do?product=WOSsearch_mode=CitationReportSID=N1Li4F2gO4DOPbIiPp5page=1cr_pqid=7viewType=summary 字段: 作者 记录 计数 %，共 192 柱状图 表格中显示的数据行 所有数据行 GURDON JB 186 96.875 % LASKEY RA 16 8.333 % DEROBERTIS EM 13 6.771 % MOHUN TJ 12 6.250 % GARRETT N 11 5.729 % BROWN DD 10 5.208 % HOPWOOD ND 9 4.688 % KATO K 9 4.688 % LEMAIRE P 9 4.688 % RYAN K 9 4.688 % 字段: 国家/地区 记录 计数 %，共 192 柱状图 表格中显示的数据行 所有数据行 ENGLAND 183 95.313 % USA 24 12.500 % FRANCE 6 3.125 % FED REP GER 5 2.604 % SCOTLAND 4 2.083 % CANADA 2 1.042 % JAPAN 2 1.042 % 字段: 文献类型 记录 计数 %，共 192 柱状图 表格中显示的数据行 所有数据行 ARTICLE 147 76.563 % REVIEW 18 9.375 % MEETING ABSTRACT 10 5.208 % DISCUSSION 8 4.167 % PROCEEDINGS PAPER 8 4.167 % EDITORIAL MATERIAL 7 3.646 % 字段: 基金资助机构 记录 计数 %，共 192 柱状图 表格中显示的数据行 所有数据行 WELLCOME TRUST 6 3.125 % CAMBRIDGE COMMONWEALTH TRUST 2 1.042 % JAPAN SOCIETY FOR THE PROMOTION OF SCIENCE 2 1.042 % NATIONAL RESEARCH FOUNDATION SOUTH AFRICA 2 1.042 % SWEDISH RESEARCH COUNCIL MEDICINE 2 1.042 % 字段: 语种 记录 计数 %，共 192 柱状图 表格中显示的数据行 所有数据行 ENGLISH 191 99.479 % 字段: 语种 记录 计数 %，共 192 柱状图 表格中显示的数据行 所有数据行 字段: 组织 记录 计数 %，共 192 柱状图 表格中显示的数据行 所有数据行 UNIV CAMBRIDGE 102 53.125 % MRC 53 27.604 % WELLCOME CRC INST 26 13.542 % CARNEGIE INST WASHINGTON 10 5.208 % NATL INST MED RES 10 5.208 % DEPT ZOOL 8 4.167 % JOHNS HOPKINS UNIV 8 4.167 % PURDUE UNIV 8 4.167 % UNIV OXFORD 8 4.167 % BAYLOR COLL MED 7 3.646 % 字段: 出版年 记录 计数 %，共 192 柱状图 表格中显示的数据行 所有数据行 1983 12 6.250 % 1977 10 5.208 % 1978 9 4.688 % 1989 8 4.167 % 1999 8 4.167 % 1996 7 3.646 % 2002 7 3.646 % 1993 6 3.125 % 1994 6 3.125 % 1997 6 3.125 % 1998 6 3.125 % 2005 6 3.125 % 1970 5 2.604 % 1973 5 2.604 % 1976 5 2.604 % 1992 5 2.604 % 2001 5 2.604 % 1974 4 2.083 % 1982 4 2.083 % 1985 4 2.083 % 1986 4 2.083 % 1987 4 2.083 % 1991 4 2.083 % 2000 4 2.083 % 2004 4 2.083 % 2008 4 2.083 % 2010 4 2.083 % 1971 3 1.563 % 1972 3 1.563 % 1979 3 1.563 % 1984 3 1.563 % 1995 3 1.563 % 2003 3 1.563 % 2011 3 1.563 % 1980 2 1.042 % 1981 2 1.042 % 1988 2 1.042 % 1990 2 1.042 % 2006 2 1.042 % 2007 2 1.042 % 2009 2 1.042 % 字段: 出版年 记录 计数 %，共 192 柱状图 表格中显示的数据行 所有数据行 字段: 研究方向 记录 计数 %，共 192 柱状图 表格中显示的数据行 所有数据行 DEVELOPMENTAL BIOLOGY 62 32.292 % CELL BIOLOGY 58 30.208 % BIOCHEMISTRY MOLECULAR BIOLOGY 46 23.958 % SCIENCE TECHNOLOGY OTHER TOPICS 43 22.396 % LIFE SCIENCES BIOMEDICINE OTHER TOPICS 15 7.813 % ANATOMY MORPHOLOGY 10 5.208 % GENERAL INTERNAL MEDICINE 9 4.688 % GENETICS HEREDITY 7 3.646 % ENVIRONMENTAL SCIENCES ECOLOGY 3 1.563 % EVOLUTIONARY BIOLOGY 3 1.563 % BIOPHYSICS 2 1.042 % 字段: 来源出版物 记录 计数 %，共 192 柱状图 表格中显示的数据行 所有数据行 NATURE 20 10.417 % PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA 19 9.896 % DEVELOPMENT 17 8.854 % CELL 12 6.250 % DEVELOPMENTAL BIOLOGY 11 5.729 % JOURNAL OF EMBRYOLOGY AND EXPERIMENTAL MORPHOLOGY 9 4.688 % CIBA FOUNDATION SYMPOSIA 8 4.167 % INTERNATIONAL JOURNAL OF DEVELOPMENTAL BIOLOGY 8 4.167 % EMBO JOURNAL 7 3.646 % CURRENT BIOLOGY 5 2.604 % JOURNAL OF MOLECULAR BIOLOGY 5 2.604 % CELL CYCLE 4 2.083 % MECHANISMS OF DEVELOPMENT 4 2.083 % COLD SPRING HARBOR SYMPOSIA ON QUANTITATIVE BIOLOGY 3 1.563 % GENES DEVELOPMENT 3 1.563 % JOURNAL OF CELLULAR BIOCHEMISTRY 3 1.563 % NATURE CELL BIOLOGY 3 1.563 % PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY OF LONDON SERIES B BIOLOGICAL SCIENCES 3 1.563 % PROCEEDINGS OF THE ROYAL SOCIETY B BIOLOGICAL SCIENCES 3 1.563 % SEMINARS IN CELL DEVELOPMENTAL BIOLOGY 3 1.563 % ANNUAL REVIEW OF CELL AND DEVELOPMENTAL BIOLOGY 2 1.042 % BIOESSAYS 2 1.042 % COMPTES RENDUS DE L ACADEMIE DES SCIENCES SERIE III SCIENCES DE LA VIE LIFE SCIENCES 2 1.042 % DIFFERENTIATION 2 1.042 % JOURNAL OF CELL BIOLOGY 2 1.042 % METHODS 2 1.042 % METHODS IN CELL BIOLOGY 2 1.042 % 字段: Web of Science 类别 记录 计数 %，共 192 柱状图 表格中显示的数据行 所有数据行 DEVELOPMENTAL BIOLOGY 62 32.292 % CELL BIOLOGY 58 30.208 % BIOCHEMISTRY MOLECULAR BIOLOGY 46 23.958 % MULTIDISCIPLINARY SCIENCES 43 22.396 % BIOLOGY 15 7.813 % ANATOMY MORPHOLOGY 10 5.208 % MEDICINE GENERAL INTERNAL 9 4.688 % GENETICS HEREDITY 7 3.646 % BIOCHEMICAL RESEARCH METHODS 3 1.563 % ECOLOGY 3 1.563 % EVOLUTIONARY BIOLOGY 3 1.563 % BIOPHYSICS 2 1.042 % ShinyaYamanaka的开创性工作是在2006年44岁时完成，被引6212次。 Takahashi, K., Yamanaka, S. (2006). Induction of pluripotent stem cells from mouse embryonic and adult fibroblast cultures by defined factors. Cell 126:663-676. 我的预测很准吧，哈哈！ Shinya Yamanaka的论文被引用情况（2010年生理学或医学诺贝尔奖得主预测） http://blog.sciencenet.cn/home.php?mod=spaceuid=280034do=blogid=365718 日本京都大学 再生医科学研究所干细胞生物学系教授、美国加州旧金山 心血管疾病研究所 高级调查员以及美国加州大学旧金山分校 解剖学教授 Shinya Yamanaka 获奖原因 因在 DNA 因发现干细胞和开发诱导多能干细胞而获奖 http://scholar.google.com.hk/scholar?hl=enq=++S+Yamanaka+++stem+cells+btnG=Searchas_sdt=2000as_ylo=as_vis=0 Induction of pluripotent stem cells from mouse embryonic and adult fibroblast cultures by defined factors K Takahashi, S Yamanaka - cell, 2006 - Elsevier Differentiated cells can be reprogrammed to an embryonic-like state by transfer of nuclear contents into oocytes or by fusion with embryonic stem (ES) cells . Little is known about factors that induce this reprogramming. Here, we demonstrate induction of pluripotent ... Cited by 6112 Related articles All 105 versions from kyoto-u.ac.jp kyoto-u.ac.jp Induction of pluripotent stem cells from adult human fibroblasts by defined factors …, M Narita, T Ichisaka, K Tomoda, S Yamanaka - cell, 2007 - repository.kulib.kyoto-u.ac.jp 抄録: Successful reprogramming of differentiated human somatic cells into a pluripotent state would allow creation of patient-and disease-specific stem cells . We previously reported generation of induced pluripotent stem (iPS) cells , capable of germline transmission, from ... Cited by 4968 Related articles All 131 versions from wisc.edu wisc.edu Generation of germline-competent induced pluripotent stem cells K Okita, T Ichisaka, S Yamanaka - Nature, 2007 - nature.com Abstract We have previously shown that pluripotent stem cells can be induced from mouse fibroblasts by retroviral introduction of Oct3/4 (also called Pou5f1), Sox2, c-Myc and Klf4, and subsequent selection for Fbx15 (also called Fbxo15) expression. These induced ... Cited by 2146 Related articles BL Direct All 49 versions from wisc.edu wisc.edu Generation of induced pluripotent stem cells without Myc from mouse and human fibroblasts …, K Okita, Y Mochiduki, N Takizawa, S Yamanaka - Nature …, 2007 - nature.com Abstract Direct reprogramming of somatic cells provides an opportunity to generate patient- or disease-specific pluripotent stem cells . Such induced pluripotent stem (iPS) cells were generated from mouse fibroblasts by retroviral transduction of four transcription factors: ... Cited by 1333 Related articles BL Direct All 18 versions from boar.or.kr boar.or.kr Generation of mouse induced pluripotent stem cells without viral vectors …, M Nakagawa, H Hyenjong, T Ichisaka, S Yamanaka - Science, 2008 - sciencemag.org Abstract Induced pluripotent stem (iPS) cells have been generated from mouse and human somatic cells by introducing Oct3/4 and Sox2 with either Klf4 and c-Myc or Nanog and Lin28 using retroviruses or lentiviruses. Patient-specific iPS cells could be useful in drug ... Cited by 927 Related articles All 23 versions from ugr.es ugr.es Generation of pluripotent stem cells from adult mouse liver and stomach cells …, K Okita, K Takahashi, T Chiba, S Yamanaka - Science …, 2008 - stke.sciencemag.org Abstract: Induced pluripotent stem (iPS) cells have been generated from mouse and human fibroblasts by the retroviral transduction of four transcription factors. However, the cell origins and molecular mechanisms of iPS cell induction remain elusive. This report describes the ... Cited by 625 Related articles All 15 versions from stanford.edu stanford.edu Strategies and new developments in the generation of patient-specific pluripotent stem cells S Yamanaka - Cell Stem Cell, 2007 - Elsevier Generating pluripotent stem cells directly from cells obtained from patients is one of the ultimate goals in regenerative medicine. Two “reprogramming” strategies for the generation of pluripotent stem cells from somatic cells have been studied extensively: nuclear transfer ... Cited by 402 Related articles All 27 versions from ccsu.edu ccsu.edu The homeoprotein Nanog is required for maintenance of pluripotency in mouse epiblast and ES cells …, K Takahashi, M Maruyama, M Maeda, S Yamanaka - cell, 2003 - ccsu.edu ... These data indicate analyses demonstrated that nanog is expressed in ES cells , but not in neural or hematopoietic stem cells (Ra- ... Positions of the probe and ScaI recognition sites ( S ) used for Southern blot were shown. ... scribed ( Yamanaka et al., 2000, 1998). ... Cited by 1765 Related articles View as HTML All 31 versions Induction of pluripotent stem cells from fibroblast cultures K Takahashi, K Okita, M Nakagawa, S Yamanaka - Nature protocols, 2007 - nature.com Abstract Clinical application of embryonic stem (ES) cells faces difficulties regarding use of embryos, as well as tissue rejection after implantation. One way to circumvent these issues is to generate pluripotent stem cells directly from somatic cells . Somatic cells can be ... Cited by 329 Related articles BL Direct All 9 versions Role of ERas in promoting tumour-like properties in mouse embryonic stem cells K Takahashi, K Mitsui, S Yamanaka - Nature, 2003 - nature.com Abstract Embryonic stem (ES) cells are pluripotent cells derived from early mammalian embryos 1, 2. Their immortality and rapid growth make them attractive sources for stem cell therapies 3; however, they produce tumours (teratomas) when transplanted, which could ... http://scholar.google.com.hk/scholar?hl=enq=++S+Yamanaka+++stem+cells+btnG=Searchas_sdt=2000as_ylo=as_vis=0
标签: capacity
