检索结果-南通市图书馆

Evaluating nebraska’s local comprehensive plans to achieve the national wetland conservation missions in the USA

在线全文

学校读者我要写书评

暂无评论

Ecosystem Health and Sustainability 2022年第1期8卷 79-93页

作者： Ligang Zhang Qiao Hu Michael Hayes Mark Burbach Tiffany Messer Yuzhen Zhou Zhenghong Tang School of Natural Resources University of Nebraska-LincolnLincolnNebraskaUSA Department of Biosystems and Agricultural Engineering University of KentuckyLexingtonKentuckyUSA Department of Statistics University of Nebraska-LincolnLincolnNebraskaUSA Community and Regional Planning Program University of Nebraska-LincolnLincolnNebraskaUSA

The *** government’s requirements and guidance for wetland conservation are reflected in a series of federal laws,regulations,and ***,the degree to which these requirements are reflected in local planning efforts is *** study using five components with 56 indicators evaluates how well wetland conservation efforts are integrated into 112 local comprehensive plans in nebraska,*** results show that the majority of local comprehensive plans pay little direct attention to wetland conservation,although many conservation efforts are conducted under the umbrella of environmental protection *** indicators include water resource protection received the highest score and was the descriptor of natural or environmental resources and resulted in the highest level of local awareness on natural *** indicator of setting goals for no net loss of wetlands received the lowest score among all indicators,demonstrating a clear gap between the national vision and the local reality of wetland *** suggest local governments need more direct and proactive inputs to improve wetland *** findings from this research provide a practical roadmap for planners globally,particularly for the developing countries,to integrate wetland conservation into the local planning systems.

关键词： Wetland conservation integration local comprehensive plan nebraska

Perspectives in Biological Nitrogen Fixation Research

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Integrative Plant Biology 2008年第7期50卷 786-798页

作者： Qi Cheng Department of Biochemistry Redox Biology Center University of Nebraska-Lincoln Lincoln Nebraska 68588 USA

Nitrogen fixation, along with photosynthesis is the basis of all life on earth. Current understanding suggests that no plant fixes its own nitrogen. Some plants （mainly legumes） fix nitrogen via symbiotic anaerobic microorganisms （mainly rhizobia）. The nature of biological nitrogen fixation is that the dinitrogenase catalyzes the reaction-splitting triple-bond inert atmospheric nitrogen （N2） into organic ammonia molecule （NH3）. All known nitrogenases are found to be prokaryotic, multi-complex and normally oxygen liable. Not surprisingly, the engineering of autonomous nitrogen-fixing plants would be a long-term effort because it requires the assembly of a complex enzyme and provision of anaerobic conditions. However, in the light of evolving protein catalysts, the anaerobic enzyme has almost certainly been replaced in many reactions by the more efficient and irreversible aerobic version that uses O2. On the other hand, nature has shown numerous examples of evolutionary convergence where an enzyme catalyzing a highly specific, O2-requiring reaction has an oxygen-independent counterpart, able to carry out the same reaction under anoxic conditions. In this review, I attempt to take the reader on a simplified journey from conventional nitrogenase complex to a possible simplified version of a yet to be discovered light-utilizing nitrogenase.

关键词： aerobic anaerobic anoxic convergent enzyme light-independent light-utilizing nitrogen fixation nitrogenase oxic protochlorophyllide reductase.

Lateral habenula neurocircuits mediate the maternal disruptive effect of maternal stress: A hypothesis

在线全文

学校读者我要写书评

暂无评论

Zoological Research 2022年第2期43卷 166-175页

作者： Ming Li Department of Psychology University of Nebraska-LincolnLincolnNE 68588USA

Up to 20%of women experience stress-related disorders during the postpartum period;however,little is known about the specific neural circuitry by which maternal stress exerts its negative impacts on mental health and maternal caregiving ***,such a circuitry should serve as an interface between the stress response system and maternal neural network,transmitting stress signals to the neural circuitry that mediates maternal *** this paper,I propose that the lateral habenula(LHb)serves this interface *** shows that the LHb plays a key role in encoding stress-induced effects and in the pathophysiology of major depression and stressrelated anxiety,and thus may play a role in maternal behavior as part of the maternal brain network.I hypothesize that maternal stress acts upon the LHb and two of its major downstream targets,i.e.,ventral tegmental area(VTA)and dorsal raphe nucleus(DRN),compromising the maternal care and contributing to postpartum mental *** hypothesis makes three predictions:(1)maternal stress enhances LHb neuronal activity;(2)activation of DRN-and VTA-projecting neurons in the LHb mimics the detrimental effects of maternal stress on maternal behavior;and(3)suppression of DRN-and VTA-projecting neurons in the LHb attenuates the detrimental effects of maternal stress on maternal care in stressed *** of this hypothesis is expected to enhance our understanding of the neurocircuit mechanisms mediating stress effects on maternal behavior.

关键词： Maternal behavior Lateral habenula(LHb) Ventral tegmental area Dorsal raphe Maternal stress Postpartum depression Postpartum anxiety

Spark plasma sintering of tungsten-based WTaVCr refractory high entropy alloys for nuclear fusion applications

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 146-154页

作者： Yongchul Yoo Xiang Zhang Fei Wang Xin Chen Xing-Zhong Li Michael Nastasi Bai Cui Department of Mechanical&Materials Engineering University of Nebraska-LincolnLincolnNE 68588USA nebraska Center for Materials and Nanoscience University of Nebraska-LincolnLincolnNE 68588USA Department of Nuclear Engineering Texas A&M UniversityCollege StationTX 77843USA

W-based WTaVCr refractory high entropy alloys (RHEA) may be novel and promising candidate materials for plasma facing components in the first wall and diverter in fusion reactors. This alloy has been developed by a powder metallurgy process combining mechanical alloying and spark plasma sintering (SPS). The SPSed samples contained two phases, in which the matrix is RHEA with a body-centered cubic structure, while the oxide phase was most likely Ta2VO6through a combined analysis of X-ray diffraction (XRD),energy-dispersive spectroscopy (EDS), and selected area electron diffraction (SAED). The higher oxygen affinity of Ta and V may explain the preferential formation of their oxide phases based on thermodynamic calculations. Electron backscatter diffraction (EBSD) revealed an average grain size of 6.2μm. WTaVCr RHEA showed a peak compressive strength of 2997 MPa at room temperature and much higher micro-and nano-hardness than W and other W-based RHEAs in the literature. Their high Rockwell hardness can be retained to at least 1000°C.

关键词： refractory high entropy alloy plasma-facing material fusion reactor spark plasma sintering

Semantic Segmentation of Sorghum Using Hyperspectral Data Identifies Genetic Associations

在线全文

学校读者我要写书评

暂无评论

Plant Phenomics 2020年第1期2卷 14-24页

作者： Chenyong Miao Alejandro Pages Zheng Xu Eric Rodene Jinliang Yang James C.Schnable Center for Plant Science Innovation University of Nebraska-LincolnLincolnNEUSA Department of Agronomy and Horticulture University of Nebraska-LincolnLincolnNEUSA Quantitative Life Sciences Initiative University of Nebraska-LincolnLincolnNEUSA Department of Mathematics and Statistics Wright State UniversityDaytonOHUSA

This study describes the evaluation of a range of approaches to semantic segmentation of hyperspectral images of sorghum plants,classifying each pixel as either nonplant or belonging to one of the three organ types(leaf,stalk,panicle).While many current methods for segmentation focus on separating plant pixels from background,organ-specific segmentation makes it feasible to measure a wider range of plant *** scored training data for a set of hyperspectral images collected from a sorghum association population was used to train and evaluate a set of supervised classification *** algorithms show acceptable accuracy for this classification *** trained on sorghum data are able to accurately classify maize leaves and stalks,but fail to accurately classify maize reproductive organs which are not directly equivalent to sorghum *** measurements extracted from semantic segmentation of sorghum organs can be used to identify both genes known to be controlling variation in a previously measured phenotypes(e.g.,panicle size and plant height)as well as identify signals for genes controlling traits not previously quantified in this population(e.g.,stalk/leaf ratio).Organ level semantic segmentation provides opportunities to identify genes controlling variation in a wide range of morphological phenotypes in sorghum,maize,and other related grain crops.

关键词： Sorghum classify organs

Optically stimulated luminescence dating of aeolian sand in the Otindag dune field and Holocene climate change

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Earth Sciences 2008年第6期51卷 837-847页

作者： Joseph MASON James SWINEHART Ronald GOBLE Department of Geography University of Wisconsin Madison School of Natural Resources IANR University of Nebraska-Lincoln Department of Geosciences University of Nebraska-Lincoln

The dune system in Otindag sand field of northern China is sensitive to climate change, where effective moisture and related vegetation cover play a controlling role for dune activity and stability. Therefore, aeolian deposits may be an archive of past environmental changes, possibly at the millennial scale, but previous studies on this topic have rarely been reported. In this study, thirty-five optically stimulated luminescence (OSL) ages of ten representative sand-paleosol profiles in Otindag sand field are ob-tained, and these ages provide a relatively complete and well-dated chronology for wet and dry varia-tions in Holocene. The results indicate that widespread dune mobilization occurred from 9.9 to 8.2 ka, suggesting a dry early Holocene climate. The dunes were mainly stabilized between 8.0 and 2.7 ka, implying a relatively wet climate, although there were short-term penetrations of dune activity during this wet period. After ~2.3 ka, the region became dry again, as inferred from widespread dune activity. The '8.2 ka' cold event and the Little Ice Age climatic deterioration are detected on the basis of the dune records and OSL ages. During the Medieval Warm Period and the Sui-Tang Warm Period (570-770 AD), climate in Otindag sand field was relatively humid and the vegetation was denser, and the sand dunes were stabilized again. These aeolian records may indicate climate changes at millennial time scale during Holocene, and these climatic changes may be the teleconnection to the climate changes elsewhere in the world.

关键词： Otindag sand field OSL dating Holocene drought dune

Can the grains offer each other helping hands?Convergent molecular mechanisms associated with domestication and crop improvement in rice and maize

在线全文

学校读者我要写书评

暂无评论

Molecular Plant 2022年第5期15卷 793-795页

作者： Ravi V.Mural James C.Schnable university of nebraska-lincoln LincolnNEUSA

The grasses,Poaceae,are an extraordinarily ecologically success-ful clade,with more than 10000 described extant *** grasses include more than 30 domesticated grain crops,ranging from maize(Zea mays),rice(Oryza sativa),and wheat(Triticum aes-tivum),which are collectively responsible for 50%of all calories consumed by humans around the world,to minor and orphan crops such as teff(Eragrostis tef),pearl millet(Pennisetum glaucum),proso millet(Panicum milaceum),and Job's tears(Coix lacryma-jobi)(Glémin and Bataillon,2009).Domestication of grain crops from their wild relatives involved a common suite of phenotypic changes,including loss of seed shattering,loss of dormancy,and increased apical dominance,which are collectively referred to as"domestication syndrome"(Glémin and Bataillon,2009).

关键词： sativa crops collective

Evaluation of UAV-derived multimodal remote sensing data for biomass prediction and drought tolerance assessment in bioenergy sorghum

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

The Crop Journal 2022年第5期10卷 1363-1375页

作者： Jiating Li Daniel P.Schachtman Cody F.Creech Lin Wang Yufeng Ge Yeyin Shi Department of Biological Systems Engineering University of Nebraska-LincolnLincolnNE 68583USA Department of Agronomy and Horticulture Center for Plant Science InnovationUniversity of Nebraska-LincolnLincolnNE 68588USA Center for Plant Science Innovation University of Nebraska-LincolnLincolnNE 68588USA Department of Agronomy and Horticulture Panhandle Research and Extension CenterUniversity of Nebraska-LincolnScottsbluffNE 69361USA

Screening for drought tolerance is critical to ensure high biomass production of bioenergy sorghum in arid or semi-arid environments. The bottleneck in drought tolerance selection is the challenge of accurately predicting biomass for a large number of genotypes. Although biomass prediction by lowaltitude remote sensing has been widely investigated on various crops, the performance of the predictions are not consistent, especially when applied in a breeding context with hundreds of genotypes. In some cases, biomass prediction of a large group of genotypes benefited from multimodal remote sensing data;while in other cases, the benefits were not obvious. In this study, we evaluated the performance of single and multimodal data(thermal, RGB, and multispectral) derived from an unmanned aerial vehicle(UAV) for biomass prediction for drought tolerance assessments within a context of bioenergy sorghum breeding. The biomass of 360 sorghum genotypes grown under well-watered and water-stressed regimes was predicted with a series of UAV-derived canopy features, including canopy structure, spectral reflectance, and thermal radiation features. Biomass predictions using canopy features derived from the multimodal data showed comparable performance with the best results obtained with the single modal data with coefficients of determination(R2) ranging from 0.40 to 0.53 under water-stressed environment and0.11 to 0.35 under well-watered environment. The significance in biomass prediction was highest with multispectral followed by RGB and lowest with the thermal sensor. Finally, two well-recognized yieldbased drought tolerance indices were calculated from ground truth biomass data and UAV predicted biomass, respectively. Results showed that the geometric mean productivity index outperformed the yield stability index in terms of the potential for reliable predictions by the remotely sensed ***, this study demonstrated a promising strategy for the use of different UAV-bas

关键词： Crop phenotyping Unmanned Aerial System(UAS) Thermal Machine learning Drought stress

Predation changes the shape of thermal performance curves for population growth rate

在线全文

学校读者我要写书评

暂无评论

Current Zoology 2016年第5期62卷 501-505页

作者： Thomas M. LUHRING John P. DELONG School of Biological Sciences University of Nebraska Lincoln Nebraska 68588 USA

Ectotherms generally demonstrate nonlinear changes in performance （e.g., movement speed, indi- vidual growth, population growth） as a function of temperature that are characterized by thermal performance curves （TPC）. Predation risk elicits phenotypic and behavioral changes that likewise impact performance measures. We tested whether exposure to predation Orthocyclops modestus impacts the maximum population growth rate （rmax） TPC of the protist Paramecium aurelia. We fit predator and non-predator exposed P. aurelia population growth rates to a function previously shown to best describe Paramecium population growth rate TPC＇s （Lactin-2） and compared subse- quent parameter estimates between curves. For Paramecium exposed to predation risk, maximum population growth increased more rapidly as temperatures rose and decreased more rapidly as temperatures fell compared to the initial temperature. The area under each TPC curve remained ap- proximately the same, consistent with the idea of a trade-off in performance across temperatures. Our results indicate TPCs are flexible given variation in food web context and that trophic inter- actions may play an important role in shaping TPCs. Furthermore, this and other studies illustrate the need for a mechanistic model of TPCs with parameters tied to biologically meaningful properties.

关键词： paramecium phenotypic plasticity predation reaction norm temperature thermal performance curve.