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Cool-season annual pastures with clovers to supplement wintering beef cows nursing calves

Journal of Animal Science and Biotechnology 2012年第4期3卷 221-226页

作者： Stacey A Gunter Whitney A Whitworth t gregory montgomery Paul A Beck United States Department of Agriculture Agricultural Research Service Southern Plains Range Research Station University of Arkansas at Monticello Division of Agriculture Southeast Research & Extension Center University of Arkansas Division of Agriculture Southwest Research & Extension Center University of Arkansas

In December of 3 years, 87 beef cows with nursing calves （.594 ± 9.8 kg; calving season, September to November） at side were stratified by body condition score, body weight, cow age, and calf gender and divided randomly into 6 groups assigned to 1 of 6 cool-season annual pastures （0.45 ha/cow） that had been interseeded into a dormant common bermudagrass （Cynodon dactylon [L.] Pers.）/bahiagrass （Paspalum notatum Flugge） sod. Pastures contained 1 of the following 3 seeding mixtures （2 pastures/mixture）： 1） wheat （triticum aestivurn L.） and ryegrass （Lofium multiflorum Lain., WRG）, 2） wheat and ryegrass plus red clover （trifolium pretense L, WRR）, or 3） wheat and ryegrass plus white （trifofium repens L.） and crimson clovers （trifolium incarnatum L., WRW）. All groups had ad libitum access to grass hay （12% crude protein; 58% total digestible nutrients）. the second week in December, cow estrous cycles were synchronized and artificially inseminated. In late December, a bull was placed with each group for 60-d. Data were analyzed with an analysis of variance using a mixed model containing treatment as the fixed effect and year as the random effect. Body weight and condition scores did not differ （P ≥ 0.27） among cows between February and June. Calf birth weights or average daily gain did not differ （P≥ 0.17） among treatments; however, calves grazing pastures with clovers did tend （P= 0.06） to weigh more than calves grazing grass only. Weaning weight per cow exposed to a bull was greater （P= 0.02） for WRR and WRW than WRG. Cows grazing winter-annual pastures containing clovers tended to wean more calf body weight per cow exposed to a bull than cows grazing the grass only pastures.

关键词： Annual ryegrass Beef cows Clovers Nitrogen Pasture 1

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Change in observed long-term greening across Switzerlandevidence from a three decades NDVI time-series and its relationship with climate and land cover factors

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Big Earth Data 2024年第1期8卷 1-32页

作者： Claire Obuchowicz Charlotte Poussin gregory Giuliani Institute for Environmental Sciences EnviroSPACE labUniversity of GenevaGenevaSwitzerland Institute for Environmental Sciences University of GenevaGenevaSwitzerland

Environmental changes are significantly modifying terrestrial vegetation dynamics,with serious consequences on Earth system functioning and provision of ecosystem *** conditions are an essential element underpinning global sustainability frameworks,such as the Sustainable Development Goals(SDGs),requiring effective solutions to assess the impacts of changing land conditions induced by various driving *** the global scale,long-term increase of vegetation greening has been widely reported notably in seasonally snow-covered ecosystems as a response to warming ***,greening trends at the national scale have received less attention,although countries like Switzerland are prone to important changing climate ***,we used a 35-year satellite-derived annual and seasonal time-series of Normalized Difference Vegetation Index(NDVI)to assess vegetation greenness evolution at different spatial and temporal scales across Switzerland and related them to temperature,precipitation,and land cover to investigate possible responses of changing climatic *** indicate that there is a statistically significant greening trend at the national scale with an NDVI mean increasing slope of 0.6%/year for the 61%significant pixels across *** particular,the seasonal mean NDVI shows an important break for winter,autumn and spring seasons starting from 2010,potentially indicating a critical point of changing land *** biogeographical scale,we observed an apparent clustering(Jura-Plateau;Northern-Southern Alps;Eastern-Western Alps)related to landscape characteristics,while forested land cover classes are more responsive to NDVI ***,the NDVI values are mostly a function of temperature at elevations below the tree line rather than *** findings suggest that multi-annual and seasonal NDVI can be a valuable indicator to monitor vegetation conditions at different scales and can provide complementary observati

关键词： Landsat climate land cover NDVI anomaly

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A numerical model to simulate the transient frictional viscoelastic sliding contact

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Friction 2024年第2期12卷 319-339页

作者： Dongze WANG gregory de BOER Anne NEVILLE Ali GHANBARZADEH School of Mechanical Engineering University of LeedsLeeds LS29JTUK

Sliding motion has always been one of the major concerns when it comes to the analysis of viscoelastic contact problems.A new model simulating the transient sliding contact of smooth viscoelastic surfaces is developed in this *** taking the dry contact friction and the coupling between shear tractions and normal pressure into account,the effect of the early partial slip period,which is often neglected in the study of viscoelastic sliding contact problems,is investigated *** with solutions based on the frictionless assumption,the steady-state pressure profile is found to be slightly different under the effect of the partial slip regime,including a lower peak pressure and the shift of the contacting region in the direction opposite to the sliding ***,the time required for the viscoelastic contact to reach its steady state is delayed owing to the partial slip period preceding the global sliding motion.

关键词： contact mechanics frictional sliding viscoelasticity viscoelastic friction

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Applying Earth Observation technologies to Economic Consequence Modeling:A Case Study of COVID‑19 in Los Angeles County,California

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International Journal of Disaster Risk Science 2024年第1期15卷 18-31页

作者： Fynnwin Prager Marina t.Mendoza Charles K.Huyck Adam Rose Paul Amyx gregory Yetman Kristy F.tiampo California State University Dominguez HillsCarsonCA 90747USA ImageCat Inc.Long BeachCA 90802USA University of Southern California Los AngelesCA 90015USA CIESIN–Center for International Earth Science Information Network Columbia UniversityPalisadesNY 10964USA Cooperative Institute for Research in Environmental Sciences(CIRES) University of Colorado BoulderBoulderCO 80309USA

Earth observation(EO) technologies,such as very high-resolution optical satellite data available from Maxar,can enhance economic consequence modeling of disasters by capturing the fine-grained and real-time behavioral responses of businesses and the *** investigated this unique approach to economic consequence modeling to determine whether crowd-sourced interpretations of EO data can be used to illuminate key economic behavioral responses that could be used for computable general equilibrium modeling of supply chain repercussions and resilience *** applied our methodology to the COVID-19 pandemic experience in Los Angeles County,California as a case *** also proposed a dynamic adjustment approach to account for the changing character of EO through longer-term disasters in the economic modeling *** found that despite limitations,EO data can increase sectoral and temporal resolution,which leads to significant differences from other data sources in terms of direct and total impact *** findings from this analytical approach have important implications for economic consequence modeling of disasters,as well as providing useful information to policymakers and emergency managers,whose goal is to reduce disaster costs and to improve economic resilience.

关键词： Computable general equilibrium models COVID-19 Disaster economic impacts Earth observation Economic consequence analysis Los Angeles County

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Is salmonid migration at risk from chemical information disruption?

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Aquaculture and Fisheries 2024年第3期9卷 378-387页

作者： Keith B.tierney gregory G.Pyle Biological Sciences College of Natural and Applied SciencesEdmontonABT6G 2E9Canada School of Public Health College of Health SciencesEdmontonABT6G 1C9Canada Department of Biological Sciences University of LethbridgeLethbridgeABT1K 3M4Canada

Good information is the basis for good *** many invaluable salmon species,chemical information is necessary to guide and fine-tune their migrations to and from freshwater mating grounds.A problem is that salmon of the current world are running a gauntlet of toxic chemicals arising from diverse anthropogenic inputs and these chemicals are known to disrupt *** is sufficient evidence that effluents from cities,mines,agriculture and industry contain chemicals that can rapidly,and sometimes irreversibly,impair the olfactory sense that salmon use to gather *** toxic inputs may not only be strong enough to impair migration,but be strong enough to redirect salmon away from their *** is also evidence that some synthetic chemicals may serve as the basis for ‘new’ information and be useful in making correct migratory *** the plus side,there are examples of new regulations that limit the input of chemicals of known olfactory toxicity,but on the minus side,increased urbanization and global climate change will likely increase the number and/or severity of some neurotoxic *** we identify the specific avenues of chemical risks to information disruption and in so doing prioritize and rank the risks to migrating *** data collected here can be used to lay the foundation for modelling the effects of anthropogenic inputs on information disruption in diverse salmonid species from around the world and therefore help secure their longevity in a changing chemical environment.

关键词： Salmon migration Ocean ranching Chemical information disruption Homing disruption Olfactory toxicity

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High temperature Iron Ethylene Polymerization Catalysts Bearing N,N,N'-2-(1-(2,4-Dibenzhydryl-6-fluorophenylimino)ethyl)-6-(1-(arylphenylimino)ethyl)pyridines

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Chinese Journal of Polymer Science 2024年第2期42卷 188-201,I0007页

作者： Chantsalnyam Bariashir Qiu-Yue Zhang Bayasgalan Ulambayar gregory A.Solan tong-Ling Liang Wen-Hua Sun Institute of Chemistry and Chemical technology Mongolian Academy of SciencesUlaanbaatar13330Mongolia Key Laboratory of Engineering Plastics and Beijing National Laboratory for Molecular Science Institute of ChemistryChinese Academy of SciencesBeijing100190China Department of Chemistry University of LeicesterUniversity RoadLeicesterLE17RHUK State Key Laboratory for Oxo Synthesis and Selective Oxidation Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou730000China

the N,N,N'-ferrous chloride complexes,[2-{CMeN(2,4-(CHPh)_(2)-6-FC_(6)H_(2))}-6-(CMeNAr)C_(5)H_(3)N]FeCl_(2)(Ar=2,6-Me_(2)C_(6)H_(3) Fe1,2,6-Et_(2)C_(6)H_(3)Fe2,2,6-^(i)Pr_(2)C_(6)H_(3) Fe3,2,4,6-Me_(3)C_(6)H_(2) Fe4 and 2,6-Et_(2)-4-MeC_(6)H_(2) Fe5),each possessing one N-2,4-dibenzhydryl-6-fluorophenyl group,were readily synthesized from their respective unsymmetrical bis(imino)pyridines,*** identification of Fe2 highlighted the variation in the steric properties provided by the dissimilar N-aryl *** pre-treatment with either MAO or MMAO,complexes Fe1-Fe5 all displayed,at an operating temperature of 80℃,high activities for ethylene polymerization with levels falling in the order:Fe4> Fe1> Fe5> Fe2> ***,Fe4/MAO displayed the highest activity of 1.94×10^(7) g_(PE)·mol_(Fe)^(-1)·h^(-1) of the study with only a modest loss in performance at 90℃.Generally,the resulting polyethylenes were highly linear(t_(m) range:122-132℃),narrowly disperse and of low molecular weight(M_(w) range:6.73-46.04kg·mol^(-1)),with the most sterically hindered Fe3 forming the highest molecular weight polymer of the ***-group analysis by ^(1)H-and ^(13)CNMR spectroscopy revealed saturated alkyl(n-propyl and i-propyl) and unsaturated vinyl chain ends indicative of the role of both β-H elimination and chain transfer to aluminum as termination *** comparison with previou sly reported iron precatalysts with similar tridentate ligand skeletons,it is evident that the introduction of a large benzhydryl group in combination with a fluorine as the ortho-substituents of one N-aryl group has the effect of enhancing thermal stability of the iron polymerization catalyst whilst maintaining appreciable polymer molecular weight.

关键词： Iron catalyst Ethylene polymerization Linear polyethylene Fluoride effect thermal stability

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Impact damage testing based on high-speed continuous water jet aircraft coatings

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Chinese Journal of Aeronautics 2024年第10期37卷 249-264页

作者： Minggong SHA Ying SUN Yutong LI Yiming LIU gregory FEDOtENKOV Lev RABINSKIY Arseniy BABAYtSEV Yulong LI School of Civil Aviation Northwestern Polytechnical UniversityXi’an 710072China Joint International Research Laboratory of Impact Dynamics and Engineering Application Xi’an 710072China Shaanxi Impact Dynamics and Engineering Application Laboratory Xi’an 710072China NPU Yangzi River Delta Research Institute Suzhou 215400China Moscow Aviation Institute(National Research University) Moscow 125993Russia

When an aircraft passes through a rainy area at high speed,the coating on the front edge of the fuselage will be continuously eroded by raindrops,causing the coating to wear,crack or even peel *** paper uses carbon fiber t300 material as the base material,and at the different impact speeds and impact numbers,water cutting equipment was used to simulate the erosion of the coating caused by the continuous impact of water *** damage morphology of samples at different damage stages was observed by digital microscope and Scanning Electron Microscope(SEM),and the damage evolution curve was established to analyze and reveal the damage behavior and damage mechanism of rain *** results show that the degree of damage experienced an increasing trend with the increase of impact numbers and speed,until circular peel damage was formed;no damage occurred during the incubation period,and the curvature of the damage evolution curve increased significantly after the expansion period and eventually showed a stable expansion *** mechanical properties of the coating material were the main influencing factors of its rain corrosion ***,the axially symmetric unsteady contact problem of droplets impacting the surface of a solid deformable body was *** the contact area was determined based on the iterative algorithm boundary positioning method.A mathematical model and closed mathematical formula describing the unsteady interaction between a droplet and a solid deformable obstacle were proposed.

关键词： Rain erosion damage Liquid-solid impact Multiple jets Composite materials Impact dynamics

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Semimartingale dynamics for a backward exchange rate process

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Probability, Uncertainty and Quantitative Risk 2024年第3期9卷 371-388页

作者： gregory Gagnon Department of Economics University of Toronto Mississauga3359 Mississauga RoadMississaugaOntarioL5L 1C6Canada

Via a forward SDE solution(k_(t),t≥O)that captures money supply dynamics,a macroeconomic model known as the monetary model generates a backward exchange rate process(y_(t),t≥0).For any t≥0,y_(t)=k_(t)+α^(-1)μ_(t) where(μ_(t),t≥0)is a backward process andα>0 is a ***,(y_(t),t≥O)does not satisfy a conventional *** paper proves(y_(t),t≥O)is a continuous semimartingale when restrictions on the SDE for(k_(t),t≥O)capture anti-inflationary *** new result in economic dynamics does not require the filtration to be the Brownian filtration.

关键词： Backward process Semimartingale Anti-inflationary SDE policy

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高温压缩变形Al-Zn-Mg-Cu合金动态再结晶后的{111}/{111}近奇异晶界

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金属学报 2024年第9期60卷 1165-1178页

作者：刘光辉王卫国 gregory S Rohrer 陈松林燕童芳冯小铮周邦新福建理工大学晶界工程研究所福州350118 福建理工大学材料科学与工程学院福州350118 Department of Materials Science and Engineering Carnegie Mellon UniversityPittsburghPA15213-3890USA 上海大学材料研究所上海200072

提高{111}/{111}近奇异晶界比例可增强Al-Zn-Mg-Cu合金晶界腐蚀抗力,为了解此类晶界形成机理并探索其调控方法,本工作将470℃、12 h和520℃、6 h双级固溶及冷轧后再结晶的Al-Zn-Mg-Cu合金样品分别在450、480和520℃进行应变速率为0.001 ... 详细信息

提高{111}/{111}近奇异晶界比例可增强Al-Zn-Mg-Cu合金晶界腐蚀抗力,为了解此类晶界形成机理并探索其调控方法,本工作将470℃、12 h和520℃、6 h双级固溶及冷轧后再结晶的Al-Zn-Mg-Cu合金样品分别在450、480和520℃进行应变速率为0.001 s^(-1)、真应变为1.20的压缩变形,压缩后立即水冷。采用电子背散射衍射和基于五参数分析的晶界界面匹配定量表征方法对上述3个样品的显微组织和晶界特征分布进行观察分析。结果表明,高温压缩后的显微组织不均匀,存在间隔分明的细晶组织和粗晶组织,其中细晶组织中的晶界以小角度晶界(LAGB)为主,粗晶组织中的晶界以大角度晶界(HAGB)为主;粗、细晶组织中的{111}/{111}近奇异晶界({111}/{111}-NSB)比例均随压缩温度的升高而增大,其中经520℃压缩的试样,其LAGB中的{111}/{111}-NSB占总晶界的比例为8.77%,HAGB中的{111}/{111}-NSB占总晶界的比例为4.53%。进一步考察各试样的应力-应变曲线以及450℃压缩30%时的显微组织特征可见,应变介于0.05~0.70为稳态流变阶段,主要发生初次动态再结晶(DRX),其主要由粗晶及其HAGB构成。应变介于0.70~1.20为二次硬化阶段,主要发生二次DRX,其中不连续DRX(DDRX)和连续DRX(CDRX)同时进行,且优先发生在某些微区;不论是DDRX因形核和核心长大生成的HAGB,还是CDRX因亚晶合并引入的LAGB,均使对应微区的晶粒细化,导致样品总体流变应力急剧上升。二次DRX阶段,CDRX行为随压缩温度的提高而增强,{111}/{111}-NSB比例也随之增加,特别是LAGB中的{111}/{111}-NSB比例快速增加。

关键词： Al-Zn-Mg-Cu合金近奇异晶界晶界界面匹配连续动态再结晶

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Association between Placental Malaria and Severe Pre-Eclampsia in two University Hospitals of Yaounde City

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Open Journal of Obstetrics and Gynecology 2024年第9期14卷 1488-1511页

作者： Ayissi gregory Astrid Ruth Ndolo Kondo Ndoumba Afouba Alice Noa Ndoua Claude Cyrille Essiben Félix Meka Esther Belinga Etienne Metogo Junie Engo Engo Samuel Désiré Bodo Edmond Lemaire tchente Nguefack Charlotte Foumane Pascal Mboudou Emile télésphore Department of Obstetrics and Gynecology Faculty of Medicine and Biomedicals Sciences University of Yaound I Yaounde Cameroon Department of Obstetrics and Gynecology Faculty of Medicine and Pharmaceuticals Sciences University of Douala Douala Cameroon Department of Morphological and Anatomo-Pathological Sciences Faculty of Medicine and Pharmaceutical Sciences University of Dschang Dschang Cameroon. Department of Morphological and Anatomo-Pathological Sciences Faculty of Medicine and Biomedicals Sciences University of Yaound I Yaounde Cameroon

Context: Pre-eclampsia and placental malaria, are two diseases that share pathophysiological similarities, such as placental ischemia, endothelial dysfunction and production of pro-inflammatory cytokines. Objective: the objective of our study was to investigate the association between placental malaria lesions and severe pre-eclampsia. Methodology: We conducted a prospective analytical cross-sectional study in two University Hospitals in the city of Yaounde (Yaounde Central Hospital and the Gynaecological Obstetrics and Paediatrics Hospital), and in the laboratory of the Centre Pasteur in Yaounde over an eight-month period (1st January 2021 – 1st September 2021). All patients with pre-eclampsia diagnosed according to the criteria of the International Society for the Study of Hypertension (ISSHP) and free of chronic metabolic or infectious pathology were included in this study. the patients were divided into two groups: group 1 (mild pre-eclampsia) and group 2: severe pre-eclampsia. Socio-demographic, clinical and histopathological characteristics specific to pre-eclampsia and placental malaria were investigated. Statistical analysis was performed with SPSS 23.0 software, Chi 2 was used to compare categorical variables, Student t-test was used to compare means, and logistic regression was used to assess the association between placental malaria lesions and PES. Results: the mean age of our study population was 29.93 ± 7.36 years versus 28.28 ± 7.18 years in patients with mild and severe pre-eclampsia respectively. Pre-eclampsia placental lesions (accelerated villous maturation, infarction) were significantly greater in patients with severe pre-eclampsia (p Conclusion: Placental malaria lesions were significantly associated with severe pre-eclampsia and increased the risk of developing severe pre-eclampsia placental lesions by a factor of 10.

关键词： Mild Pre-Eclampsia Severe Pre-Eclampsia Malaria Placental Lesions Association

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