检索结果-南通市图书馆

effects of mountain pine beetle-killed forests on source water contributions to streamflow in headwater streams of the Colorado Rocky Mountains

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of earth Science 2017年第3期11卷 496-504页

作者： Christine e. WeHNeR john D. STeDNICK Watershed Science Program College of Natural Resources Colorado State University Fort Collins CO 80523-1472 USA

Natural or human-influenced disturbances are important to the health and diversity of forests, which in turn, are important to the water quantity and quality exported from a catchment. However, human-induced disturbances （prescribed fire and harvesting） have been decreasing, and natural disturbances （fires and insects） have been increasing in frequency and severity. One such natural disturbance is the mountain pine beetle （MPB）, （Denclroctonus ponderosae） an endemic species. A recent epidemic resulted in the mortality of millions of hectares of lodgepole pine （Pinus contorta） forests in Colorado, USA. Beetle-induced tree mortality brings about changes to the hydrologic cycle, including decreased transpiration and interception with the loss of canopy cover. This study examined the effect of the mountain pine beetle kill on source water contributions to streamflow in snowmelt- dominated headwater catchments using stable isotopes （2H and ~80） as tracers. Study catchments with varying level of beetle-killed forest area （6% to 97%） were sampled for groundwater, surface water, and precipitation. Streams were sampled to assess whether beetle-killed forests have altered source water contributions to streamflow. Ground- water contributions increased with increasing beetle-killed forest area （p = 0.008）. Both rain and snow contributions were negatively correlated with beetle-killed forest area （p = 0.035 and p = 0.011, respectively）. As the beetle-killed forest area increases, so does fractional groundwater contribution to streamflow.

关键词： mountain pine beetle isotope tracers stream-flow generation headwaters

Analyzing neural degeneration of the retina with connectomics

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2022年第1期17卷 113-114页

作者： Charles L.Zucker john e.Dowling Department of Molecular and Cellular Biology Harvard UniversityCambridgeMAUSA

electron microscopy(eM)provides a unique ability to visualize structural detail with a resolution orders of magnitude better than other imaging *** conventionally,its limitation is that each acquired image represents a small area with a section thickness significantly less than 100 ***,techniques have been developed that allow thousands of relatively large serial-sections to be collected and efficiently imaged at full eM resolution,with the images then being stitched back together to produce a 3D volume.

关键词： neural image Applied

Rapid Identification of Rice Samples Using an electronic Nose

在线全文

学校读者我要写书评

暂无评论

Journal of Bionic engineering 2009年第3期6卷 290-297页

作者： john Westbrook W.C.Hoffmann R.e.Lacey USDA-ARS College Station Department of Biological and Agricultural engineering Texas A&M UniversityCollege Station

Four rice samples of long grain type were tested using an electronic nose (Cyranose-320).Samples of 5 g of each variety of rice were placed individually in vials and were analyzed with the electronic nose unit consisting of 32 polymer *** Cyranose-320 was able to differentiate between varieties of *** chemical composition of the rice odors for differentiating rice samples needs to be *** optimum parameter settings should be considered during the Cyranose-320 training process especially for multiple samples,which are helpful for obtaining an accurate training model to improve identification ***,it is necessary to investigate the e-nose sensor selection for obtaining better classification accuracy.A re- duced number of sensors could potentially shorten the data processing time,and could be used to establish an application pro- cedure and reduce the cost for a specific electronic *** research is needed for developing analytical procedures that adapt the Cyranose-320 as a tool for testing rice quality.

关键词： rice grain identification electronic nose data analysis pattern recognition

Proportional-integral-derivative control of nonlinear half-car electro-hydraulic suspension systems

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & engineering) 2013年第6期14卷 401-416页

作者： john e. D. eKORU Jimoh O. PeDRO School of Mechanical Aeronautical and Industrial Engineering University of the Witwatersrand Private Bag 03 WITS 2050 Johannesburg South Africa

This paper presents the development of a proportional-integral-derivative (PID)-based control method for application to active vehicle suspension systems (AVSS). This method uses an inner PID hydraulic actuator force control loop, in combination with an outer PID suspension travel control loop, to control a nonlinear half-car AVSS. Robustness to model uncertainty in the form of variation in suspension damping is tested, comparing performance of the AVSS with a passive vehicle suspension system (PVSS), with similar model parameters. Spectral analysis of suspension system model output data, obtained by performing a road input disturbance frequency sweep, provides frequency response plots for both nonlinear vehicle suspension systems and time domain vehicle responses to a sinusoidal road input disturbance on a smooth road. The results show the greater robustness of the AVSS over the PVSS to parametric uncertainty in the frequency and time domains.

关键词： Force control Proportional-integral-derivative (PID) control Nonlinear half-car Active vehicle suspension system (AVSS) Hydraulic actuator dynamics Model uncertainty

Olfactory Dysfunction as an early Biomarker in Parkinson's Disease

在线全文

学校读者我要写书评

暂无评论

Neuroscience Bulletin 2017年第5期33卷 515-525页

作者： Michelle e.Fullard James F.Morley john e.Duda Parkinson's Disease Research Education and Clinical Center Corporal Michael J. Crescenz VA Medical CenterPhiladelphia PA 19104 USA Department of Neurology University of Pennsylvania School of Medicine Philadelphia PA 19104 USA

Olfactory dysfunction is common in Parkinson＇s disease （PD） and often predates the diagnosis by years, reflecting early deposition of Lewy pathology, the histo- logic hallmark of PD, in the olfactory bulb. Clinical tests are available that allow for the rapid characterization of olfactory dysfunction, including tests of odor identification, discrimination, detection, and recognition thresholds, memory, and tests assessing the build-up of odor intensity across increasing suprathreshold stimulus concentrations. The high prevalence of olfactory impairment, along with the ease and low cost of assessment, has fostered great interest in olfaction as a potential biomarker for PD. Hyposmia may help differentiate PD from other causes of parkinsonism, and may also aid in the identification of ＂pre-motor＂ PD due to the early pathologic involvement of olfactory pathways. Olfactory function is also correlated with other non-motor features of PD and may serve as a predictor of cognitive decline. In this article, we summarize the existing literature on olfaction in PD, focusing on the potential for olfaction as a biomarker for early or differential diagnosis and prognosis.

关键词： Olfaction · Parkinson's disease · Biomarker ·Parkinsonism · Pathology

Vasectomy by epithelial curettage without suture or cautery： a pilot study in humans

在线全文

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2010年第3期12卷 315-321,I0008页

作者： john K. Amory john W. Jessen Charles Muller Richard e. Berger Department of Medicine Center for Research in Reproduction and Contraception University of Washington School of Medicine Seattle WA 98195 USA private Practice Dentistry Seattle WA 98195 USA Department of Urology University of Washington School of Medicine Seattle WA 98195 USA

Curettage of the epithelium of the vas deferens might be a safe and effective method of male sterilization. We conducted a pilot study of vasectomy by epithelial curettage with a novel microcurette called the Vas-X in 12 normal men requesting elective sterilization. Seminal fluid analysis was obtained monthly after the procedure for 6 months. Pain was assessed by questionnaire. Three months after the procedure, all men attained sperm concentrations of less than 0.2 million sperm per mL, and seven were azoospermic. Post-procedural pain was minimal. Nine men ultimately achieved and maintained azoospermia; however, 4 to 6 months after the procedure, sperm concentrations increased in three of the 12 subjects, necessitating repeat vasectomy. Microscopic examination of the vas deferens from these failures revealed re-canalization. Vasectomy by epithelial curettage can result in effective sterilization; however, 1/4 of the subjects were not effectively sterilized by the procedure due to re-canalization of the vas deferens. epithelial curettage will require further refinement to determine if it is a viable form of vasectomy.

关键词： male contraception male sterilization re-canalization spermatogenesis vas deferens vasectomy failure

Passive technologies for future large-scale photonic integrated circuits on silicon: polarization handling, light non-reciprocity and loss reduction

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Light(Science & Applications) 2012年第1期1卷 134-145页

作者： Daoxin Dai Jared Bauters john e Bowers Department of electrical and Computer engineering University of CaliforniaSanta BarbaraCA 93106USA Centre for Optical and electromagnetic Research State Key Laboratory for Modern Optical InstrumentationZhejiang UniversityZijingangHangzhou 310058China

Silicon-based large-scale photonic integrated circuits are becoming important,due to the need for higher complexity and lower cost for optical transmitters,receivers and optical *** this paper,passive technologies for large-scale photonic integrated circuits are described,including polarization handling,light non-reciprocity and loss *** design rule for polarization beam splitters based on asymmetrical directional couplers is summarized and several novel designs for ultra-short polarization beam splitters are reviewed.A novel concept for realizing a polarization splitter–rotator is presented with a very simple fabrication *** of silicon-based light non-reciprocity devices(e.g.,optical isolator),which is very important for transmitters to avoid sensitivity to reflections,is also demonstrated with the help of magneto-optical material by the bonding ***-loss waveguides are another important technology for large-scale photonic integrated ***-low loss optical waveguides are achieved by designing a Si3N4 core with a very high aspect *** loss is reduced further to,0.1 dB m21 with an improved fabrication process incorporating a high-quality thermal oxide upper cladding by means of wafer *** the developed ultra-low loss Si3N4 optical waveguides,some devices are also demonstrated,including ultra-high-Q ring resonators,low-loss arrayed-waveguide grating(de)multiplexers,and high-extinction-ratio polarizers.

关键词： integration low loss non-reciprocal polarization silicon

Probabilistic ecological risk assessment for three chlorophenols in surface waters of China

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 environmental Sciences 2012年第2期24卷 329-334页

作者： Liqun Xing Hongling Liu john e Giesy Xiaowei Zhang Hongxia Yu State Key Laboratory of Pollution Control and Resource Reuse School of the Environment Nanjing University Nanjing 210046 China. Department of Veterinary Biomedical Sciences and Toxicology Centre University of Saskatchewan Saskatoon Saskatchewan Canada Department of Biology ＆ Chemistry City University of Hong Kong Kowloon Hong Kong SAR China Zoology Department College of Science King Saud University P. O. Box 2455 Riyadh 11451 Saudi Arabia

Individual and combined assessment of risks of adverse effects to aquatic ecosystems of three chlorophenols（CPs）,including 2,4dichlorophenol（2,4-DCP）,2,4,6-trichlorophenol（2,4,6-TCP） and pentachlorophenol（PCP）,were conducted.A probabilistic approach based on the concentrations of CPs in surface waters of China was used to determine the likelihood of adverse *** potential risk of CPs in surface waters of China was determined to be of concern,especially PCP and mixtures of *** risks of adverse effects were examined as the joint probabilities of exposure and *** joint probability for PCP was 0.271 in the worst case and 0.111 in the median case,*** on the cumulative probability,5% of aquatic organisms included in the assessment would be affected 21.36% of the time in the worst case and 5.99% of the time in median case,*** the mixtures of CPs,the joint probability were 0.171 in the worst case and 0.503 in median case,respectively and 5% of species would be affected 49.83% of the time for the worst case and 12.72% in the median case,*** of effects of the individual CPs,2,4-DCP and 2,4,6-TCP were deemed to be acceptable with a overlapping probability of 0.1 with 5% of species being affected less than 4% of the time.

关键词： probabilistic risk assessment chlorophenols surface water joint probability curve

Mediating National History and Personal Catastrophe: Televising Holocaust Memorial Day Commemoration

在线全文

学校读者我要写书评

暂无评论

Fudan Journal of the Humanities and Social Sciences 2018年第4期11卷 465-485页

作者： john e.Richardson Department of Social Science Loughborough UniversityEpinal WayLoughborough Leicestershire LE11 3TUUK

This article explores the rhetoric and mass mediation of the national Holocaust Memorial Day (HMD)commemoration ceremony,as broadcast on British *** the recommendation of the Stockholm International Forum,since 2001,Britain has commemorated victims of the Holocaust and subsequent genocides on 27 *** national commemoration has been broadcast on television five times:in 2001,2002,2005,2015 and *** programmes both reflect and illuminate the complex processes of (national)histories,individual memory and collective remembrance,and the ways that they mediate and interact with each other in social and historic contexts.I argue that these televised ceremonies orientate to four communicative metafunctions,the combination of which is particular to this media *** aim to simultaneously achieve four things:to Communicate History ('what happened');to Communicate Values ('why we commemorate');to Communicate Solemnity ('how we commemorate');and to Communicate Hope ('that we are not defined by this catastrophic past').In this article,I examine:the ways that these metafunctions are communicated through words,music and images;and 'some of the ways that these metafunctions can rhetorically derail,undermining their communication.

关键词： Broadcasting Television Holocaust Memorial Day Commemoration Rhetorical analysis