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1.
ABSTRACT

Educational outreach, especially from land-grant universities, will have a more prominent, visible role in the twenty-first century. There is a widespread belief among university leaders that the effect of universities must reach beyond the limits of the campus to positively influence the social, cultural and economic well-being of constituents. Enhanced outreach efforts will involve all academic units and provide appropriate faculty rewards for their accomplishments. Existing extension/outreach organizations such as Cooperative Extension Services will expand their base to draw from the total university expertise and knowledge base. Funding will be a challenge as public resources become less available. Distance education through satellite communications and other advanced technology will be a growing part of education outreach.  相似文献   

2.
The Matica Srpska, a society for cultural promotion, was founded in 1826 in Budapest. In the society, a gallery, a publishing house, a library, and a museum were formed. The Matica Srpska Library (MSL) was moved to Novi Sad, Yugoslavia, in 1864. The Library is one of eight Yugoslav national libraries serving as depository libraries. MSL is well known for its valuable collection of old and rare books and newspapers. Since Yugoslavia does not have a national agricultural library, the Yugoslav part of the international AGRIS database is produced in the MSL. MSL contributes to JUBIB, a Yugoslav bibliographic database.  相似文献   

3.
In this study a new computerized approach and linear models (LMs) to solve the UV/vis spectroscopy interference effects of beta-carotene with lycopene analysis by neural networks (NNs) are considered. The data collected (absorbance values) obtained by UV/vis spectrophotometry were transferred into an NN-trained computer for modeling and prediction of output. Such an integrated NN/UV/vis spectroscopy approach is capable of estimating beta-carotene and lycopene concentrations with a mean prediction error 50 times lower than that calculated by the LM/UV/vis spectroscopy approach (without any previous physicochemical knowledge of the process to be modeled).  相似文献   

4.
ABSTRACT

A brief overview is provided of the policies, responsibilities, procedures and current projects of the Gift and Exchange Unit of the National Agricultural Library (NAL). Exchange operations which formed a part of the earliest library traditions of the U.S. Department of Agriculture now aid NAL in meeting the challenges of acquisitions operations which must adapt continually during an era of rapid technological change and stringent funding.  相似文献   

5.
This study describes how University of Minnesota Extension staff locate and use information to accomplish daily activities. The major findings were: (a) information seeking is a daily or weekly need; (b) staff use predominately online resources from a variety of sources—peer-reviewed journals, technical or research reports, and government information—and use search engines most frequently to locate them; and (c) Extension staff are aware of the majority of library resources and services. Extension staff welcome advanced information-seeking tools and techniques for professional development.  相似文献   

6.
ABSTRACT

Much of what defines the national character of Americans, as well as the nation's social structure, landscape, environment, and economy, is rooted in our agricultural past This remarkable story of the American experience is captured in a broad band of documentary resources that include the memoirs and transactions of early agricultural societies and almanacs, extension service publications, archives, photographs, oral histories and periodicals for farm families and the agricultural “trade.” However, older materials, especially those printed on poor-quality paper, are often severely deteriorated, brittle and fragile. To lose these materials would be to lose an invaluable record of American values and the nation's scientific and business enterprise.

The united States Agricultural Information Network (USAIN) proposes a national program to preserve in the original or in an archivally sound format–and make readily accessible to scholars, researchers, students, and scientists–the most important pre-1950 published literature and the primary unpublished resources that together document the history of the agricultural sciences in the United States. Participants will be land-grant institutions, the National Agricultural Library, and other libraries, societies, and archives with important historical collections. A USAIN-appointed national steering committee will govern and develop funding for the program and recruit a Coordinator to work with participating institutions to develop suitable preservation projects. The first priority is the preservation of scholarly monographs and journals identified as the core historical literature of the agricultural sciences. Projects will employ a hybrid mix of technologies (e.g., preservation microfilming, conservation of originals, and digital scanning), which reflect requirements for both archival soundness and improved access. The program will also assure that records for preserved items are included in national databases and that storage conditions for archival copies meet national standards. The plan envisions formation of a “National Agriculture Literature Archive” at the National Agricultural Library.  相似文献   

7.
分析了国家农业图书馆用户对馆藏电子资源的利用情况,探讨了用户的信息利用特点和需求规律,并在网络管理、资源建设和信息服务等方面提出了一些建议。  相似文献   

8.
Water Movement Characteristics in a Multi-Soil-Layering System   总被引:2,自引:0,他引:2  
The Multi-Soil-Layering (MSL) system consists of soil units arranged in a brick-like pattern that are surrounded by layers of zeolite or alternating particles with a homogeneous size that allow a high hydraulic loading rate. Characteristics of the changes in the water movement, hydraulic retention time (HRT) and system weight during the wastewater treatment in the MSL system were investigated using a laboratory-scale MSL system (D10 × W50 × H73 cm). As the loading rate increased from 1,000 to 5,500 L m−2 d−1, wastewater preferentially flowed into the permeable layers in the MSL, which decreased the contact of the wastewater with the soil mixture layers. HRT was inversely related to the loading rate. HRT decreased from 20 to 1 h, as the loading rate increased from 250 to 6,000 L m−2 d−1. As an indicator of the system condition, the weight variation of the system was determined during the wastewater treatment. When the weight was stable, input and output of wastewater and decomposition of organic matter appeared to be equilibrated. When the weight increased, the system started to clog. Due to clogging, the efficiency of COD and phosphorus removal decreased, while the efficiency of nitrate removal increased.  相似文献   

9.
This article outlines the history of the Doris S. Kirschner Cookbook Collection at the University of Minnesota's Magrath Library and details a survey of this collection's users. Because the collection does not circulate, the survey was undertaken to find out some information about who uses this collection and why. Respondents to the survey consisted of primarily University of Minnesota staff and their uses of the collection were varied, encompassing personal, academic, and creative uses. The results of this survey will be used as a basis for further exploration as well as targeted marketing of the collection.  相似文献   

10.
Abstract

Multi-soil-layering (MSL) system was designed for purifying domestic wastewater and for treating polluted river water. MSL system is typically comprised of layers of soil mixture blocks alternating with permeable layers. The permeable layer has roles of preventing clogging and to increasing the efficiency of infiltration of wastewater through the soil mixture blocks. In this study, the comparative efficiency of five MSL systems as a function of five permeable layer materials (zeolite, zeolitized perlite, perlite, gravel, and charcoal) was investigated. The MSL systems were constructed in 15 × 50 × 100 cm boxes where the soil mixture blocks contained sandy clay soil, kenaf + corncob, and iron scraps at a ratio of 6 : 1 : 1 by weight, respectively, and filled up in alternation with the permeable layer. The results indicated that all the MSL systems at loading rates of 96–346 L m?2 d?1 under nonaerated conditions were able to reduce the levels of COD (342–1,231 mg L?1), BOD5 (201–802 mg L?1), and soluble reactive phosphorus (SRP) (3.5–10.1 mg P L?1) at percentages of 79.0–98.1, 80.0–99.6, and 97.1–100%, respectively. The zeolite and the charcoal-based MSL systems under a 96–346 L m?2 d?1 loading rate effectively reduced the level of TN (41.4–65.5 mg N L?1) at percentages of 79.0–92.1 and 30.7–88.9%, respectively. In terms of prevention of clogging, the charcoal-based MSL system was the most effective, followed by the gravel and zeolite-based MSL. The apparent efficiency of pollutant removal, for zeolitized perlite, perlite, and gravel-based MSL systems was low. With an on-off aeration operation, the efficiency of the MSL systems in the reduction of the levels of COD, BOD5 , and SRP (hereafter reference to as “removal”) was significantly enhanced. Overall, the zeolite-based MSL system seemed to be more effective than the other MSL systems. However, if optimum aeration could be obtained, the removal efficiency of charcoal-based MSL system might be improved. Aeration at a rate of 64,000 L m?3 d?1 for 1 week alternating with 2 weeks of nonaeration enhanced the removal of COD, BOD5 , and SRP but not that of TN.  相似文献   

11.
A classical soil line (SL) in the RED–NIR spectral space is specified by two coefficients “a” and “b.” In this form, it does not characterize soil types and subtypes. A multitemporal soil line (MSL) represents the major axis of the ellipse describing all possible pairs of RED–NIR values characterizing a bare soil surface for a given pixel of remote sensing images. The MSL in the RED–NIR spectral space is specified by several (N) coefficients. The resulting N-dimensional space of MSL coefficients makes it possible to give unique characteristics for each type and subtype of soils in the following zonal soil sequence: soddy-podzolic soils, light gray forest soils, gray forest soils, dark gray forest soils, podzolized chernozems, and leached chernozems. The analysis of variance allows us to state that the soils of this sequence significantly differ from one another in the characteristic sets of MSL coefficients. In other words, these coefficients characterize soil types and subtypes, and the MSL can be considered an empirical soil line (ESL) of the given type and subtype of soil. A classical SL is an integrity of ESLs of different soils within the given scene of remote sensing data.  相似文献   

12.
过量施肥造成的农业面源污染已成为太湖水质下降及富营养化的主要原因之一。该试验在距离太湖湖岸带约1 km的小麦种植区对2种杨麦间作密度(其株距均为2 m,行距分别为5 m(AS1)和15 m(AS2))削减土壤氮流失效应进行研究。结果表明:杨树林冠层对降雨的截留主要集中于4-10月,AS1间作密度下林冠层对降雨的截留幅度达8.6%~44.5%。由于林冠层对降雨的再分配作用导致的径流量AS1R(去除枯落物:Remove litter)处理显著低于AS2R和MSL0(单作麦地中未铺设枯落物处理)处理(P0.05)。在整个小麦生长季,AS1S(有枯落物覆盖:Save litter)处理径流中TN、NO3--N平均浓度、流失量均显著低于MSL0(P0.05)。60 cm土层AS1S平均淋溶水量、TN、NO3--N平均浓度和流失量与AS2S、MSL0之间均存在显著差异(P0.05)。在杨树落叶期,AS1系统有枯落物覆盖下地表径流量、TN、NO3--N平均浓度和流失量均显著低于无枯落物处理(P0.05)。而AS2系统有无枯落物覆盖之间差异则不显著(P0.05)。在去除冠层及枯落物影响后,AS1R处理60 cm土层淋溶水量、TN和NO3--N淋溶流失量均显著低于20cm土层(P0.05),而MSL0系统下20、40、60 cm之间差异均不显著(P0.05)。由此可见,株行距为2 m×5 m的杨麦间作密度对地表径流、淋溶及氮流失的削减效应更显著。  相似文献   

13.
为揭示玉米/大豆套作体系下土壤氮素转换的调控机理和根际微生态效应,以种植模式为主因素[设玉米单作(MM)、大豆单作(SS)和玉米/大豆套作(IMS)3种处理],以玉米、大豆施氮总量(玉米、大豆施氮比例为3∶1)为副因素[设不施氮(NN,0 kg?hm~(-2))、减量施氮(RN,180 kg?hm~(-2))和常量施氮(CN,240 kg?hm~(-2))3个处理],研究了玉米/大豆套作系统下不同施氮量对作物根际土壤微生物数量及土壤酶活性的影响。结果表明:与相应单作相比,套作下玉米根际土壤真菌、放线菌数量分别提高25.37%和8.79%;套作大豆根际土壤真菌、放线菌、固氮菌数量高于单作大豆;套作玉米根际土壤蛋白酶、脲酶活性和套作大豆根际土壤蛋白酶活性均显著升高。各施氮水平间,减量施氮下玉米、大豆根际土壤真菌数量较常量施氮和不施氮均有所提高;施氮提高了玉米、大豆根际土壤放线菌数量;大豆根际土壤固氮菌数量以减量施氮最高,比不施氮和常量施氮高17.78%和5.67%;玉米根际土壤蛋白酶活性、脲酶活性和大豆根际土壤脲酶活性均以减量施氮为最高。适宜的施氮量不仅能增加玉米/大豆套作土壤中真菌、放线菌、固氮菌的数量,还能提高土壤蛋白酶、脲酶活性,调节土壤氮素的转化,促进玉米/大豆对土壤中氮素的吸收,实现节能增效。  相似文献   

14.
The National CD-ROM Sampler is a collection of significant Extension material collected from across the United States, and was a project requested by the National Agricultural Library (NAL) and the Extension Service/United States Department of Agriculture (ES/USDA0 to investigate and evaluate the use of CD-ROM technology as a means for storing and distributing Extension-related information. This article recounts the experiences of the Interactive Design and Development (IDD) staff in producing the Sampler. Also included are major evaluation findings from the project and recommendations sent forth to NAL and ES/USDA.  相似文献   

15.

Purpose

Although arsenic (As) hyperaccumulation is a constitutive property for Pteris vittata, there is intraspecific variation in As accumulation among metallicolous (from As-contaminated soils) and nonmetallicolous populations (from uncontaminated soils) and the related mechanisms is still not clear.

Materials and methods

Pot trials, hydroponic culture, and manual simulation were conducted to investigate the roles of arsenate reductase and root exudates in accumulating As in P. vittata, which were collected from two uncontaminated sites including Sun Yat-sen University campus, Guangdong Province (ZD), and a botanical garden in Guangxi Academy of Forestry Sciences, Nanning City, Guangxi Province (NN), and two As and Pb/Zn mining and/or smelting sites located in Shaoguan of Guangdong Province (SG) and Guiyang of Hunan Province (GY).

Results and discussion

The nonmetallicolous populations (ZD and NN) possessed more efficient uptake of arsenate and arsenite than the metallicolous populations (SG and GY). There were significant (p?<?0.05) difference in arsenate reductase activities in roots among the four populations of P. vittata and that the higher arsenate reductase activities were recorded in the nonmetallicolous populations (110 nkat mg?1 protein for ZD, 160 nkat mg?1 protein for NN) compared with the metallicolous populations (62.9 nkat mg?1 protein for SG, 78.1 nkat mg?1 protein for GY). Root exudates from the nonmetallicolous population (NN) and the metallicolous population (GY) of P. vittata contained similar compositions of organic acids including oxalic, malic, and succinic acids, of which oxalate were dominant (>?67%). The NN population exuded 4.23 times more oxalate than the SG population. Root exudates from the NN population mobilized significantly (p?<?0.05) more As from As-contaminated soils than those from the SG population, of which oxalate had the most effective in As mobilization.

Conclusions

The present study suggests that higher arsenate reductase activities and oxalate exudation in the nonmetallicolous populations may play an important role in increasing their efficiency in phytoremediation of As-contaminated soils.
  相似文献   

16.
控释肥、普通肥分层施肥对氮磷钾养分迁移的影响   总被引:1,自引:0,他引:1  
为了研究不同分层施肥对养分迁移的影响,通过土柱淋洗试验,以混施(肥料撒施后翻耕)为对照,设置不施肥、普通尿素和控释尿素分别与磷钾肥掺混后进行1层(深度5cm)、2层(5,10cm)、3层(5,10,15cm)施肥处理,研究不同分层施肥处理对养分淋洗总量、肥料养分淋洗率的影响。结果表明,普通肥分层施肥的无机氮淋洗总量显著低于对照,其中3层施肥处理最低,且显著低于其他各处理;控释肥各分层施肥处理无机氮淋洗量总体低于控释肥混施,但未达显著水平;各分层施肥处理对有效磷的总淋洗量无显著影响;普通肥3层施肥处理速效钾淋洗总量最高,且显著高于普通肥混施,而控释肥分层施肥中速效钾淋洗总量也是以3层施肥处理最高,且显著高于控释肥1层施肥。不同分层施肥对肥料养分淋洗率表现出较大差异,普通肥混施处理氮淋洗率为9.9%,普通肥1层、2层、3层处理淋洗率分别为6.31%,4.91%,2.70%,分层施肥各处理淋洗率均显著低于混施处理,控释肥混施处理淋洗量为3.28%,控释肥1层、2层、3层处理淋洗率分别为1.48%,2.00%,2.63%,分层施肥处理淋洗率均低于混施处理,但未达显著水平;普通肥分层施肥处理磷肥损失率为0.03%~0.05%,而控释肥分层施肥处理磷肥损失率为0.07%~0.08%,均未达显著水平;普通肥分层施肥处理中混施钾肥淋洗率为0.35%,1层、2层、3层施肥处理淋洗率分别为0.40%,0.49%,0.55%,其中3层处理淋洗率显著高于混施处理,控释肥混施处理钾肥淋洗量为0.24%,1层、2层、3层施肥处理淋洗率分别为0.20%,0.27%,0.37%,其中控释肥3层淋洗率显著高于混施处理。各处理pH总体为7.22~8.24,各次淋洗各处理间pH无显著差异,各处理电导率随着淋洗的进行出现显著的下降,第1次淋洗普通肥各处理电导率为7547.00~9360.00μS/cm,控释肥各处理电导率为5570.00~9370.00μS/cm,至第4次则分别下降为1985.67~2470.00μS/cm与1804.67~2576.67μS/cm。综上,普通尿素分层施肥无机氮淋洗总量显著低于肥料混施,以3层施肥最低;控释尿素各分层施肥无机氮淋洗量总体低于肥料混施,但差异不显著;各分层施肥对磷素总淋洗量无显著影响;普通肥3层施肥速效钾淋洗总量显著高于肥料混施;随着淋洗次数的增多,各处理淋溶液电导率均出现显著的下降,pH则不同程度上升。  相似文献   

17.
  【目的】  探讨干湿交替灌溉与氮肥形态对水稻光合特性及氮肥利用的影响。  【方法】  以徐稻3号为材料,在防雨棚内按处理数量构建9 m × 1.5 m × 0.4 m水泥池,用于2因素3水平完全区组试验。因素1为灌溉方式:浅水层灌溉 (0 kPa,CK)、轻度干湿交替灌溉 (?20 kPa)、重度干湿交替灌溉 (?40 kPa)。因素2为氮素形态:100%NH4+-N (NH)、50%NH4+-N+50%NO3–-N (1/2NH+1/2NN)、100%NO3–-N (NN)。在水稻分蘖盛期、幼穗分化始期、抽穗期和成熟期取植株样品,测定水稻根系氮代谢酶活性、叶片光合荧光特性及植株各部位氮素含量。  【结果】  在相同氮肥形态下,轻度干湿交替灌溉根系硝酸还原酶 (NR)、谷氨酰胺合成酶 (GS)、谷氨酸合成酶 (GOGAT)、谷氨酸脱氢酶 (GDH) 活性与浅水对照相比分别增加6.4%~80.4%、8.1%~85.9%、5.1%~61.8%与13.4%~94.0%;叶片光合速率及最大光化学效率得到提升;水稻产量、光合氮素利用率及氮肥农学效率明显提高,重度干湿交替灌溉则抑制根系NR、GS、GOGAT及GDH活性,降低叶片光合速率及最大光化学效率,最终导致水稻产量、光合氮素利用率及氮肥农学效率显著降低 (P < 0.05)。在浅水对照下,NH处理可改善根系氮代谢酶活性,提高叶片光合速率及最大光化学效率,有利于水稻产量、光合氮素利用率及氮肥农学效率的提升。干湿交替灌溉下,铵硝混合处理提高了根系氮代谢酶活性,增加了叶片光合速率及最大光化学效率,提高了水稻产量、光合氮素利用率及氮肥农学效率。相关分析表明,根系GS、GOGAT及GDH活性及叶片光合速率、最大光化学效率与氮素农学效率呈显著 (P < 0.05) 或极显著 (P < 0.01) 的正相关关系,而非光化学猝灭系数则与氮肥吸收利用率呈显著的负相关关系 (P < 0.05)。  【结论】  水稻生长期一直保持浅水层时,供应100%铵态氮可以充分发挥水肥的耦合效应,促进根系氮代谢酶活性,提高叶片的光合速率及最大光化学效率,有利于水稻的高产及氮高效利用。轻度干湿交替灌溉则以施用50%铵态氮和50%硝态氮混合氮肥最佳。  相似文献   

18.
Characteristics of the treatment processes inside a MSL system were investigated by using a laboratory-scale MSL system, which was set up in a D 10 × W 50 × H 73 cm acrylic box enclosing "soil mixture blocks" alternating with permeable zeolite layers. For the study of the treatment processes inside the system, wastewater, with mean concentrations (mg L−1) of COD: 70, T-N: 12, T-P: 0.9, was introduced into the system at a loading rate of 1,000 L m−2 d−1. Treatment processes in the MSL system were different for the COD, P and N pollutants. Eighty percent of COD was removed in the 1st soil layer among the 6 layers, and the removal rate increased as water moved down and finally reached 90% in the last layer of the system. Phosphorus concentration was lower under the soil mixture layers than under the permeable layers, presumably because P was adsorbed mainly by soil and mixed iron particles. The P concentration in water gradually decreased in the lower layers of the system. The concentration of PO43--P was generally lower in the aerated MSL system than in the non-aerated one. NH4+-N was adsorbed and nitrified in the upper part of the system. The NO3-N concentration was lower in water under the soil mixture layers than under the permeable layers, indicating that denitrification mainly occurred in the soil mixture layers.  相似文献   

19.
ABSTRACT

The size of the United States' coastal population is expected to increase dramatically by the year 2010, with more than 151 million additional people moving into coastal counties. This will result in our nation's coastal population swelling by nearly 27% since 1980. Rising pressures on fragile coastal resources will accompany this population growth. While increased regulation can reduce some anticipated environmental damage, university based outreach is seen as critical to advancing appropriate behavior by residents and visitors. Sea Grant outreach staff conducting this educational programming are spread over 36 states and territories. To overcome the handicap of disparate locations, networked computing is being pilot tested to increase collaboration between these marine Extension staff. Successful experiences to date suggest that emerging information technology can assist a wide variety of outreach professions to integrate their efforts.  相似文献   

20.
The soil erosion research and soil and water conservation global community lost a treasured member on November 20, 2020, when Dr. John Matthew Laflen (Fig. 1) died. Always one with a friendly welcoming smile, John had hundreds of friends, both personally and professionally throughout the world. This article includes many of his professional and scientific contributions, and impacts from his research and outreach activities.  相似文献   

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