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Rangeland hillslope lengths:A case study at the Walnut Gulch Experimental Watershed,southeastern Arizona

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International Soil and Water Conservation Research 2022年第4期10卷 597-609页

作者： Li Li Mark A.Nearing Philip Heilman Mary H.Nichols d.P.Guertin C.J.williams School of Natural Resources and the Environment University of ArizonaTucsonAZ85705USA USdA-Agricultural Research Service Southwest Watershed Research CenterTucsonAZ85719USA

Rangeland hillslopes provide much of the sediment supplied to channel systems and their lengths exert a fundamental constraint on hillslope diffusive ***,information regarding lengths of rangeland hillslopes,and how best to estimate them,is *** this study,three groups of watersheds(10 in total)were selected from the Walnut Gulch Experimental Watershed according to their geology,soil and vegetation *** 1 watersheds were at lower elevations dominated by shrubs,Group 3 were at high elevations dominated by grass,and Group 2 were mixed shrub and *** hillslope lengths were calculated from 1 m-resolution dEMs using three methods:a flow routing algorithm,slope-area relationships,and inverted relationship with drainage *** that characterize the current watersheds,including Hack's exponent and coefficient,watershed shape coefficient,channel concavity and steepness,and surface roughness,were quantified and related to hillslope *** shows:(1)estimated hillslope lengths were different for the three methods and between the three groups of watersheds;(2)hillslope lengths that measured from the flow routing algorithm for the ten selected watersheds primarily ranged from 30 to 100 m,with a median value of 63.0 m,which was 20%e50%greater than those derived from slope-area plots or drainage densities;(3)hillslope lengths estimated from the flow routing method were greater in Group 3 watersheds than in Group 2 and then in Group 1 *** attributed these differences in hillslope lengths to the historic epeirogenic pulses,watershed and drainage network morphology,and differences in vegetation characteristics;(4)measured hillslope lengths from the flow routing algorithm were best correlated with hillslope relief,then surface roughness,channel steepness and *** results would benefit the applications of hydrological and erosion models in rangelands.

关键词： Rangeland hillslope Slope length drainage density Slope-area relationship Hillslope hydrology

Increased Light, Moderate, and Severe Clear-Air Turbulence in Response to Climate Change

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Advances in Atmospheric Sciences 2017年第5期34卷 576-586页

作者： Paul d. williams department of Meteorology University of Reading Reading RG6 6BB United Kingdom

Anthropogenic climate change is expected to strengthen the vertical wind shears at aircraft cruising altitudes within the atmospheric jet streams. Such a strengthening would increase the prevalence of the shear instabilities that generate clear-air turbulence. Climate modelling studies have indicated that the amount of moderate-or-greater clear-air turbulence on transatlantic flight routes in winter will increase significantly in future as the climate changes. However,the individual responses of light,moderate,and severe clear-air turbulence have not previously been studied,despite their importance for aircraft operations. Here,we use climate model simulations to analyse the transatlantic wintertime clear-air turbulence response to climate change in five aviation-relevant turbulence strength categories. We find that the probability distributions for an ensemble of 21 clear-air turbulence diagnostics generally gain probability in their right-hand tails when the atmospheric carbon dioxide concentration is doubled. By converting the diagnostics into eddy dissipation rates,we find that the ensembleaverage airspace volume containing light clear-air turbulence increases by 59%(with an intra-ensemble range of 43%–68%),light-to-moderate by 75%(39%–96%),moderate by 94%(37%–118%),moderate-to-severe by 127%(30%–170%),and severe by 149%(36%–188%). These results suggest that the prevalence of transatlantic wintertime clear-air turbulence will increase significantly in all aviation-relevant strength categories as the climate changes.

关键词： turbulence climate change aviation jet stream

How do molecular interactions affect fluorescence behavior of AIEgens in solution and aggregate states?

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Science China Chemistry 2022年第1期65卷 135-144页

作者： Ying Yu Hao Xing Zhicong Zhou Junkai Liu Herman H-YSung Ian d.williams Jonathan E.Halpert Zheng Zhao Ben Zhong Tang department of Chemistry the Hong Kong Branch of Chinese National Engineering Research Center for Tissue Restoration and ReconstructionDepartment of Chemical and Biomedical EngineeringInstitute for Advanced Studyand Guangdong-Hong Kong-Macao Joint Laboratory of Optoelectronic and Magnetic Functional MaterialsThe Hong Kong University of Science and TechnologyClear Water BayKowloonHong KongChina Shenzhen Institute of Molecular Aggregate Science and Engineering School of Science and EngineeringChinese University of Hong KongShenzhenGuangdong518172China department of chemistry The Hong Kong University of Science and TechnologyClear Water BayKowloonHong KongChina AIE Institute Guangzhou Development DistrictHuangpuGuangzhou 510530China

Molecular interactions are crucial in diverse fields of protein folding,material science,nanotechnology,and life *** mounting experimental research controls luminescent behavior by adjusting molecular interactions in light-emitting materials,it remains elusive to correlate microscopic molecular interactions with macroscopic luminescent behavior ***,we synthesized three red luminogens with subtle structural variation and investigated the influence of molecular interactions on their luminescent behavior in solution and aggregate *** results indicate that strongπ-πand d-A interactions in both dilute solution(between luminogen and solvent molecules)and aggregate(between luminogens)states cause the redshift in emission,while weak interactions(e.g.,Van der Waals,C–H…π,and C–H…F interactions)enhance the quantum *** work provides a thoughtful investigation into the complicated influence of various molecular interactions on luminescent behavior.

关键词： molecular interactions fluorescence behaviors AIEgens aggregates

Endoscopic management of biliary strictures after liver transplantation

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World Journal of Gastroenterology 2009年第30期15卷 3725-3733页

作者： Emmanuelle d williams Peter V draganov division of Gastroenterology University of FloridaGainesvilleFL 32610-0214United States

Bile duct strictures remain a major source of morbidity after orthotopic liver transplantation (OLT). Biliary strictures are classifi ed as anastomotic or non-anastomotic strictures according to location and are defi ned by distinct clinical behaviors. Anastomotic strictures are localized and short. The outcome of endoscopic treatment for anastomotic strictures is excellent. Nonanastomotic strictures often result from ischemic and immunological events, occur earlier and are usually multiple and longer. They are characterized by a far less favorable response to endoscopic management, higher recurrence rates, graft loss and need for retransplantation. Living donor OLT patients present a unique set of challenges arising from technical factors, and stricture risk for both recipients and donors. Endoscopic treatment of living donor OLT patients is less promising. Current endoscopic strategies for biliary strictures after OLT include repeated balloon dilations and placement of multiple side-by-side plastic stents. Lifelong surveillance is required in all types of strictures. despite improvements in incidence and long term outcomes with endoscopic management, and a reduced need for surgical treatment, the impact of strictures on patients after OLT is signifi cant. Future considerations include new endoscopic technologies and improved stents, which could potentially allow for a decreased number of interventions, increased intervals before retreatment, and decreased reliance on percutaneous and surgical modalities. This review focuses on the role of endoscopy in biliary strictures, one of the most common biliary complications after OLT.

关键词：肝移植狭窄胆管内镜

Competition and body size in plants:the between-species tradeoff for maximum potential versus minimum reproductive threshold size

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Journal of Plant Ecology 2011年第3期4卷 115-122页

作者： Amanda J.Tracey lonnie W.Aarssen department of Biology Queen’s UniversityKingstonON K7L 3N6Canada

Aims According to traditional theory,superior competitive ability in plants generally requires relatively large plant body *** even within the most crowded vegetation,most resident species are relatively small;species size distributions are right-skewed at virtually every *** examine a potential explanation for this paradox:small species coexist with and outnumber large species because they have greater‘reproductive economy’,*** are better equipped—and hence more likely—to produce offspring despite severe size suppression from intense *** Randomly placed plots within old-field vegetation were surveyed across the growing *** each plot,the largest(MAX)and smallest(MIN)reproductive individuals of each resident species were collected for above-ground dry mass *** tested three hypotheses:(i)smaller resident species(with smaller MAX size)have generally smaller reproductive threshold sizes;(ii)smaller resident species have greater‘reproductive economy’,i.e.a smaller MIN relative to MAX reproductive plant size;and(iii)MIN size predicts plot occupancy(species abundance within the community)better than MAX *** Findings The results supported the first and third,but not the second ***,we could not reject the hypothesis that smaller species have greater reproductive economy,as it was not possible to record data for the largest potential plant size for each species—since even the largest(MAX)plants collected from our sampled plots were subjected to competition from neighbours under these natural field ***,contrary to conventional competition theory,more successful species(in terms of greater plot occupancy)had smaller minimum not larger(or smaller)maximum reproductive *** results suggest that a small reproductive threshold size,commonly associated with relatively small potential body size,is generally more effective in transmitting genes into future generations when selection

关键词： competition coexistence fitness old-field d reproductive economy species size distribution

Review of screening for pancreatic cancer in high risk individuals

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World Journal of Gastroenterology 2011年第19期17卷 2365-2371页

作者： Alina Stoita Ian d Penman david B williams department of Gastroenterology St Vincent's Hospital 390 Victoria StreetDarlinghurst2010NSWAustralia Centre for Liver and digestive disorders Royal Infirmary of Edinburgh51 Little France CrescentEdinburghEH16 4SAUnited Kingdom

Pancreatic cancer is difficult to diagnose at an early stage and is associated with a very poor *** percent of pancreatic cancers result from genetic susceptibility and/or familial *** from families with multiple affected first-degree relatives and those with a known cancer-causing genetic mutation have been shown to be at much higher risk of developing pancreatic *** efforts have focused on detecting disease at an earlier stage to improve survival in these high-risk *** article reviews high-risk groups,screening methods,and current screening programs and their results.

关键词：高危人群胰腺癌筛查早期阶段遗传易感性基因突变家族

Quiet in the nest:The nest environment attenuates song in a grassland songbird

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Avian Research 2023年第4期14卷 623-629页

作者： Sarah L.dobney Mikayla M.K.Bornais d.Ryan Norris Amy E.M.Newman Heather williams Stéphanie M.doucet daniel J.Mennill department of Integrative Biology University of WindsorWindsorOntarioN9B 3P4Canada department of Integrative Biology University of GuelphGuelphOntarioN1G 2W1Canada Biology department Williams CollegeWilliamstownMA01267USA

The nest environment may limit the ability of nest-bound birds to hear sounds from the outside *** vocal learning species,such as humans and songbirds,it is vital for young animals to hear the voices of conspecific animals early in *** songbirds,nest structure varies considerably across species,and the resulting impact on sound transmission may have consequences for vocal learning in *** this study,we tested the hypothesis that the nest environment attenuates song of Savannah Sparrows(Passerculus sandwichensis),grassland songbirds that build nests on the ground under cover of dense *** recorded live Savannah Sparrows singing at variable distances from 21 *** recorded songs using one microphone inside the nest(the typical position of a nestling)and another placed 1 m directly above the nest(a typical position of an adult).We found a substantial reduction in signal-to-noise ratio,where songs recorded inside the nest were an average of 11 dB lower than songs recorded directly above the *** estimate that the attenuation imposed by the nest reduced the maximum acoustic environment from 117.7 m(for recordings above the nest),to 78.6 m(for recordings within the nest),which is analogous to listening from a position 39.1 m farther away from the *** research estimated that song transmits up to 100 m in this species,so any adult male within 100 m of a young bird was previously considered a potential vocal *** reducing the nestling acoustic environment from 100 m to 78.6 m,the number of male tutors available to nestlings is reduced by an average of 27%.Given the growing evidence that song learning begins very early in life,future research on vocal development should account for how the structural properties of the natal environment affect the songs that nestlings hear.

关键词： Acoustic environment Nest environment Songbird Sound attenuation Vocal learning

Object Tracking-Based “Follow-Me” Unmanned Aerial Vehicle (UAV) System

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Computer Systems Science & Engineering 2022年第6期41卷 875-890页

作者： Olubukola d.Adekola Onyedikachi Kenny Udekwu Oluwatobi Tolulope Saliu damilola williams dada Stephen O.Maitanmi Victor Odumuyiwa Olujimi Alao Monday Eze Funmilayo Abibat Kasali Ayokunle Omotunde department of Software Engineering Babcock UniversityIlisan-RemoOgun StateNigeria department of Computer Science Babcock UniversityIlisan-RemoOgun StateNigeria department of Computer Science University of LagosAkokaLagos StateNigeria department of Computer Science and Mathematics Mountain Top UniversityOgun StateNigeria

The applications of information technology (IT) tools and techniqueshave, over the years, simplified complex problem solving procedures. But thepower of automation is inhibited by the technicality in manning advanced equipment. To this end, tools deliberately combating this inhibition and advancing technological growth are the Unmanned Aerial Vehicles (UAVs). UAVs are rapidlytaking over major industries such as logistics, security, and *** others, this is a very efficient way of carrying out missions unconventional to humans. An application area of this technology is the local film industrywhich is not producing quality movies primarily due to the lack of technicalknow-how in utilizing these systems. This study therefore aim to devise an autonomous object tracking UAV system that would eliminate the complex procedureinvolved in stabilizing an aerial camera (aerial bot) midair and promote the creation of quality aerial video shooting. The study adopted Unified Modeling Language (UML) tools in modeling the system’s functionality. The traditionalServer-Client model architecture was adopted. The OpenCV library employedproved highly efficient in aiding the tracking procedure. The system provided ausable web controller which provides easy interaction between the pilot and thedrone. Conclusively, investments in UAVs would enhance creation of quality graphic contents.

关键词： Artificial intelligence cinematography unmanned aerial vehicles drones object tracking

Crustacean parasites associated with hermit crabs from the western Mediterranean Sea,with first documentation of egg predation by the burrowing barnacle Trypetesa lampas(Cirripedia:Acrothoracica:Trypetesidae)

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Integrative Zoology 2011年第1期6卷 13-27页

作者： Jason d.williams Alejandra GALLARdO Angela E.MURPHY department of Biology Hofstra UniversityHempsteadNYUSA

Parasitic isopods(family Bopyridae)and burrowing barnacles(family Trypetesidae)infesting hermit crabs were investigated from shallow subtidal collections made along the southeastern coast of Spain in 2009.A total of 713 specimens of Clibanarius erythropus(Latreille,1818)and 82 Calcinus tubularis(L.,1767)were *** shells and worm tubes inhabited by hermit crabs were collected by hand while snorkeling and were cracked to determine host species,size,sex and presence of *** species of bopyrid isopods were found on ***:the branchial parasite Bopyrissa fraiseii(Carayon,1943)and the abdominal parasite Parathelges cardonae Codreanu and Codreanu in Codreanu,*** all *** examined,Bopyrissa fraiseii was found on 0.6%of hermit crabs and *** was found on 0.3%.A redescription of *** is provided and the species is documented with light and scanning electron microscopy for the first *** Calcinus tubularis harbored parasitic isopods,but one specimen was parasitized by an unidentified rhizocephalan barnacle of the genus Septosaccus(1.2%).The burrowing barnacle Trypetesa lampas(Hancock,1849)was found associated with both hermit crab species and evidence of predation on host eggs by this barnacle is shown for the first *** lampas was found in 4.2%of the shells *** present study expands our knowledge of the parasite fauna of hermit crabs from the Mediterranean Sea and indicates that additional research is needed to determine the impact of trypetesid egg predators on hermit crab populations.

关键词： Bopyridae egg predator Isopoda parasitism Rhizocephala