摘要：The *** of Agriculture’s agricultural research service(USDAARS)maintains seven in situ soil moisture networks throughout the continental United States,some since *** networks are crucial for understanding the spatial and temporal extent of droughts in their historical context,parameterization of hydrologic models,and local agricultural decision ***,the estimates from these networks are dependent upon their ability to provide reliable soil moisture information at a large *** is also not known how many network stations are sufficient to monitor watershed scale ***,the objectives of this research were to:(1)determine how temporally stable these networks are,including the relationships between various sensors on a year-to-year and seasonal basis,and(2)attempt to determine how many sensors are required,within a network,to approximate the full network *** data from seven in situ,it is concluded that approximately 12 soil moisture sensors are sufficient in most environments,presuming their locations are distributed to capture the hydrologic heterogeneity of the *** is possible to install a temporary network containing a suitable number of sensors for an appropriate length of time,glean stable relationships between locations,and retain these insights moving forward with fewer sensor resources.

摘要：Most authorities concede sediment from soil erosion to be the largest single stream pollutant. Physical damage from sediment includes reservoir storage loss, navigation channel filling, stream channel morphology alterations, ecological impacts, and clogging of drainage pathways. Ultimately, soil erosion is a very expensive problem. In the United States, accelerated soil erosion has been an ongoing issue since the establishment of the colonies. Through the initiative of great minds and the labor of countless individuals, the USDA was established and continues to fight for the people, providing assistance, guidance, and research. In this manuscript, the historical groundwork is laid for the establishment of the USDA-ARS National Sedimentation Laboratory (NSL) and a synopsis of NSL research is provided. This brief perspective of soil erosion research conducted on behalf of the people is but a small portion of the illustrious history of the USDA.

摘要：Human noroviruses(HuNoVs)are major foodborne pathogens that cause nonbacterial acute gastroenteritis *** the tissue-culture system for HuNoVs is not mature enough for routine detection of the virus,detection is mainly dependent on molecular approaches such as reverse transcription polymerase chain reaction(RT-PCR)and reverse transcription quantitative real-time polymerase chain reaction(RTqPCR).The widely used primers and probes for RT-qPCR were established in the early *** HuNoVs are highly variant viruses,viral genome mutations result in previously designed primers and/or probes that were perfectly matched working less efficiently over *** this study,a new duplex RT-qPCR(ND-RT-qPCR)was designed for the detection of genogroup Ⅰ(GⅠ)and genogroup Ⅱ(GⅡ)HuNoVs based on an analysis of viral sequences added in the database after *** long transcribed viral RNAs,the results demonstrate that the sensitivity of ND-RT-qPCR is as low as one genomic copy for both GⅠ and GⅡ *** performance of ND-RT-qPCR was further evaluated by a comparison with the commonly used Kageyama primer/probe sets for RT-qPCR(Kageyama RT-qPCR)for 23 HuNoV-positive clinical *** five GⅠ samples were registered as positive by ND-RT-qPCR,whereas only two samples were registered as positive by Kageyama *** 18 GⅡ samples were registered as positive by ND-RT-qPCR,while 17 samples were registered as positive by Kageyama *** sensitivity reflected by the quantification cycle(Cq)value was lower in ND-RT-qPCR than in Kageyama *** data suggest that ND-RT-qPCR could be a good fit for the detection of current strains of HuNoVs.

摘要：基于镰孢菌ITS序列,设计一对应用于实时荧光定量PCR(Real-Time QPCR)反应的镰孢菌属特异性引物TS和TR,并建立了相应的Real-Time QPCR体系。应用该反应体系,绝对定量了无肥(NF)、化肥(NP)以及化肥配施有机肥(NPM)等3种施肥措施下大豆田土壤镰孢菌DNA含量。结果表明:引物TS和TR对镰孢菌属真菌有较好的特异性;Real-Time QPCR反应的扩增曲线中各梯度浓度标准品的循环阈值(Ct值)间隔均匀,熔点曲线无杂峰,标准曲线的相关系数R2=0.993,斜率为-0.2927;在大豆生育时期的苗期,NF、NP及NPM措施下土壤镰孢菌总DNA每克干土中含量分别为18.33、44.61和140.83 pg,且NPM措施含量极显著高于NF及NP措施(P<0.01)。