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Articles 3811 - 3840 of 3873
Full-Text Articles in Physical Sciences and Mathematics
A Thermoviscoelastic Beam Model For Brakes, Kenneth Kuttler, J. Bajkowski, J. R. Fernandez, M. Shillor
A Thermoviscoelastic Beam Model For Brakes, Kenneth Kuttler, J. Bajkowski, J. R. Fernandez, M. Shillor
Faculty Publications
A model for the dynamic thermomechanical behavior of a viscoelastic beam which is in frictional contact with a rigid rotating wheel is presented. It describes a simple braking system in which the wheel comes to a stop as a result of the frictional traction generated by the beam. Friction is modelled with a temperature and slip rate dependent coefficient of friction. Frictional heat generation is taken into account as well as the wheel temperature evolution, and the wear of the beam's contacting end. The model is formulated as a variational inequality. A FEM numerical scheme for the model is described, …
Fast Registration Of Tabular Document Images Using The Fourier-Mellin Transform, William A. Barrett, Luke A. D. Hutchison
Fast Registration Of Tabular Document Images Using The Fourier-Mellin Transform, William A. Barrett, Luke A. D. Hutchison
Faculty Publications
A new technique is presented for quickly identifying global affine transformations applied to tabular document images, and to correct for those transformations. This technique, based on the Fourier-Mellin transform, is used to register (align) a set of tabular documents to each other. Each component of the affine transform is handled separately, which dramatically reduces the total parameter space of the problem. This method is robust, and deals with all components of the affine transform in a uniform way. The Fourier-Mellin transform is also extended to handle shear, which can approximate a small amount of perspective distortion, and to not need …
Measuring Polynomial Invariants Of Multiparty Quantum States, Matthew S. Leifer, N. Linden, A. Winter
Measuring Polynomial Invariants Of Multiparty Quantum States, Matthew S. Leifer, N. Linden, A. Winter
Mathematics, Physics, and Computer Science Faculty Articles and Research
We present networks for directly estimating the polynomial invariants of multiparty quantum states under local transformations. The structure of these networks is closely related to the structure of the invariants themselves and this lends a physical interpretation to these otherwise abstract mathematical quantities. Specifically, our networks estimate the invariants under local unitary (LU) transformations and under stochastic local operations and classical communication (SLOCC). Our networks can estimate the LU invariants for multiparty states, where each party can have a Hilbert space of arbitrary dimension and the SLOCC invariants for multiqubit states. We analyze the statistical efficiency of our networks compared …
Guided Model Checking With A Bayesian Meta-Heuristic, Michael D. Jones, Peter Lamborn, Kevin Seppi
Guided Model Checking With A Bayesian Meta-Heuristic, Michael D. Jones, Peter Lamborn, Kevin Seppi
Faculty Publications
This paper presents a formal verification algorithm for finding errors in models of complex concurrent systems. The algorithm improves explicit guided model checking by applying the Empirical Bayes method to revise heuristic estimates of the distance from a given state to an error state. Guided search using the revised estimates finds errors with less search effort than the original estimates.
Uranium Oxide As A Highly Reflective Coating From 100-400 Ev, Richard L. Sandberg, David D. Allred, Luke J. Bissell, Jed E. Johnson, R. Steven Turley
Uranium Oxide As A Highly Reflective Coating From 100-400 Ev, Richard L. Sandberg, David D. Allred, Luke J. Bissell, Jed E. Johnson, R. Steven Turley
Faculty Publications
We present the measured reflectances (Beamline 6.3.2, ALS and LBNL) of naturally oxidized uranium and naturally oxidized nickel thin films from 100-460 eV (2.7 to 11.6 nm) at 5 and 15 degrees grazing incidence. These show that uranium as UO2, can fulfill its promise as the highest known single surface reflector for this portion of the soft x-ray region, being nearly twice as reflective as nickel in the 124-250 eV (5-10 nm) region. This is due to its large index of refraction coupled with low absorption. Nickel is commonly used in soft x-ray applications in astronomy and synchrotrons. (Its reflectance …
Atmospheric Variability Of Methyl Chloride During The Last 300 Years From An Antarctic Ice Core And Firn Air, M. Aydin, Eric S. Saltzman, Warren J. De Bruyn, S. A. Montzka, J. H. Butler, M. Battle
Atmospheric Variability Of Methyl Chloride During The Last 300 Years From An Antarctic Ice Core And Firn Air, M. Aydin, Eric S. Saltzman, Warren J. De Bruyn, S. A. Montzka, J. H. Butler, M. Battle
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
Measurements of methyl chloride (CH3Cl) in Antarctic polar ice and firn air are used to describe the variability of atmospheric CH3Cl during the past 300 years. Firn air results from South Pole and Siple Dome suggest that the atmospheric abundance of CH3Cl increased by about 10% in the 50 years prior to 1990. Ice core measurements from Siple Dome provide evidence for a cyclic natural variability on the order of 10%, with a period of about 110 years in phase with the 20th century rise inferred from firn air. Thus, the CH3Cl increase measured in firn air may largely be …
Correlation Between Atmospheric Co2 Concentration And Vegetation Greenness In North America: Co2 Fertilization Effect, C. Lim, Menas Kafatos, P. Megonigal
Correlation Between Atmospheric Co2 Concentration And Vegetation Greenness In North America: Co2 Fertilization Effect, C. Lim, Menas Kafatos, P. Megonigal
Mathematics, Physics, and Computer Science Faculty Articles and Research
The possibility that rising atmospheric CO2 concentrations are influencing plant growth in contemporary ecosystems has received little attention, and the studies that exist have been done on a small spatial scale. We correlated the monthly rate of relative change in normalized differenced vegetation index (NDVI) from advanced very high resolution radiometer (AVHRR) data to the rate of change in atmospheric CO2 concentration during the natural vegetation growing season for evidence of a possible CO2 fertilization effect on vegetation development. The study addressed seasonal and annual patterns in spatially averaged NDVI for 3 different ecological regions in North America from 1982 …
Anomaly-Free Component Adaptation With Class Overriding, Atanas Radenski
Anomaly-Free Component Adaptation With Class Overriding, Atanas Radenski
Mathematics, Physics, and Computer Science Faculty Articles and Research
Software components can be implemented and distributed as collections of classes, then adapted to the needs of specific applications by means of subclassing. Unfortunately, subclassing in collections of related classes may require re-implementation of otherwise valid classes just because they utilize outdated parent classes, a phenomenon that is referred to as the subclassing anomaly. The subclassing anomaly is a serious problem since it can void the benefits of component-based programming altogether. We propose a code adaptation language mechanism called class overriding that is intended to overcome the subclassing anomaly. Class overriding does not create new and isolated derived classes as …
Assessment Of Organic And Inorganic Pollutants In The Offshore Sediments, Dubai, Uae., Haifa Darwish Ahmad Al Darwish
Assessment Of Organic And Inorganic Pollutants In The Offshore Sediments, Dubai, Uae., Haifa Darwish Ahmad Al Darwish
Theses
The investigated area covers the maximum fragments of Dubai offshore in the Arabian Gulf. The sediment samples were collected from fifteen stations starting by Al-Mamzar mouth and ending by Ras Ghantoot in order to assess the organic and inorganic pollutants affecting the coastal region in Dubai.
The textural class was determined through grain-size analysis and the mineral composition was identified by X-Ray diffraction. The organic pollutants were characterized through the determination of Total Organic Carbon (TOC), Total Kjeldahl Nitrogen (TKN), Total Petroleum Hydrocarbons (TPH), Polycyclic Aromatic Hydrocarbons (PAHs), Polychlorinated biphenyls (PCBs) and individual polychlorinated biphenyls. On the other hand the …
Coalescence Remnant Of Spinning Binary Black Holes, J Baker, M. Campanelli, C. O. Lousto, R. Takahashi
Coalescence Remnant Of Spinning Binary Black Holes, J Baker, M. Campanelli, C. O. Lousto, R. Takahashi
Physics & Astronomy Faculty Publications
We compute the gravitational radiation generated in the evolution of a family of close binary black hole configurations, using a combination of numerical and perturbative approximation methods. We evolve the binaries with spins s aligned or counteraligned with the orbital angular momentum from near the innermost stable circular orbit down to the final single rotating black hole. For the moderately spinning holes studied here the remnant Kerr black holes formed at the end of an inspiral process have rotation parameters a/M≈0.72+0.32(s/mH), suggesting it is difficult (though not excluded) to end up with near maximally rotating holes from such scenarios.
Generation Of The Transient Electrical And Spontaneous Magnetic Fields By Solid State Combustion, Karen S. Martirosyan, J. R. Claycomb, J. H. Miller Jr., D. Luss
Generation Of The Transient Electrical And Spontaneous Magnetic Fields By Solid State Combustion, Karen S. Martirosyan, J. R. Claycomb, J. H. Miller Jr., D. Luss
Physics & Astronomy Faculty Publications
Experiments revealed that transient electric field intensities up to 2.5 V/cm were generated during the initial period of combustion synthesis of the ferromagnetic products before the maximum temperature was reached. This occurred when the iron particles were partially oxidized and the reaction product was mainly magnetite sFe3O4d. The electromagnetic field caused spontaneous magnetization of the product in the postcombustion zone. Magnetic field values up to 4 µT formed after the sample temperature fell below the Curie temperature and the initial reactants were completely converted to the ferromagnetic phase PbFe12O19. Increasing the volume of the samples increases the absolute residual magnetic …
Setting Upper Limits On The Strength Of Periodic Gravitational Waves From Psr J1939+2134 Using The First Science Data From The Geo 600 And Ligo Detectors, B. P. Abbott, R. Abbott, Mario C. Diaz, Wm. R. Johnston, Joseph D. Romano, Cristina V. Torres
Setting Upper Limits On The Strength Of Periodic Gravitational Waves From Psr J1939+2134 Using The First Science Data From The Geo 600 And Ligo Detectors, B. P. Abbott, R. Abbott, Mario C. Diaz, Wm. R. Johnston, Joseph D. Romano, Cristina V. Torres
Physics & Astronomy Faculty Publications
Data collected by the GEO 600 and LIGO interferometric gravitational wave detectors during their first observational science run were searched for continuous gravitational waves from the pulsar J1939+2134 at twice its rotation frequency. Two independent analysis methods were used and are demonstrated in this paper: a frequency domain method and a time domain method. Both achieve consistent null results, placing new upper limits on the strength of the pulsar’s gravitational wave emission. A model emission mechanism is used to interpret the limits as a constraint on the pulsar’s equatorial ellipticity.
First Upper Limits From Ligo On Gravitational Wave Bursts, B. P. Abbott, R. Abbott, Mario C. Diaz, Wm. R. Johnston, Joseph D. Romano, Cristina V. Torres
First Upper Limits From Ligo On Gravitational Wave Bursts, B. P. Abbott, R. Abbott, Mario C. Diaz, Wm. R. Johnston, Joseph D. Romano, Cristina V. Torres
Physics & Astronomy Faculty Publications
We report on a search for gravitational wave bursts using data from the first science run of the Laser Interferometer Gravitational Wave Observatory (LIGO) detectors. Our search focuses on bursts with durations ranging from 4 to 100 ms, and with significant power in the LIGO sensitivity band of 150 to 3000 Hz. We bound the rate for such detected bursts at less than 1.6 events per day at a 90% confidence level. This result is interpreted in terms of the detection efficiency for ad hoc waveforms (Gaussians and sine Gaussians) as a function of their root-sum-square strain hrss; typical sensitivities …
Analysis Of Ligo Data For Gravitational Waves From Binary Neutron Stars, B. P. Abbott, R. Abbott, Wm. R. Johnston, Joseph D. Romano, V. Schmidt
Analysis Of Ligo Data For Gravitational Waves From Binary Neutron Stars, B. P. Abbott, R. Abbott, Wm. R. Johnston, Joseph D. Romano, V. Schmidt
Physics & Astronomy Faculty Publications
We report on a search for gravitational waves from coalescing compact binary systems in the Milky Way and the Magellanic Clouds. The analysis uses data taken by two of the three LIGO interferometers during the first LIGO science run and illustrates a method of setting upper limits on inspiral event rates using interferometer data. The analysis pipeline is described with particular attention to data selection and coincidence between the two interferometers. We establish an observational upper limit of R
Analysis Of First Ligo Science Data For Stochastic Gravitational Waves, B. P. Abbott, R. Abbott, Mario C. Diaz, Wm. R. Johnston, Joseph D. Romano
Analysis Of First Ligo Science Data For Stochastic Gravitational Waves, B. P. Abbott, R. Abbott, Mario C. Diaz, Wm. R. Johnston, Joseph D. Romano
Physics & Astronomy Faculty Publications
We present the analysis of between 50 and 100 h of coincident interferometric strain data used to search for and establish an upper limit on a stochastic background of gravitational radiation. These data come from the first LIGO science run, during which all three LIGO interferometers were operated over a 2-week period spanning August and September of 2002. The method of cross correlating the outputs of two interferometers is used for analysis. We describe in detail practical signal processing issues that arise when working with real data, and we establish an observational upper limit on a f−3 power spectrum of …
New Methods For Exafs Analysis In Structural Genomics, Grant Bunker, Nicholas Dimakis, Gocha Kelashvili
New Methods For Exafs Analysis In Structural Genomics, Grant Bunker, Nicholas Dimakis, Gocha Kelashvili
Physics & Astronomy Faculty Publications
Data analysis is one of the remaining bottlenecks in high-throughput EXAFS for structural genomics. Here some recent developments in methodology are described that offer the potential for rapid and automated XAS analysis of metalloproteins.
Probing Molecular Free Energy Landscapes By Periodic Loading, Oliver Braun, Andreas Hanke, Udo Seifert
Probing Molecular Free Energy Landscapes By Periodic Loading, Oliver Braun, Andreas Hanke, Udo Seifert
Physics & Astronomy Faculty Publications
Single molecule pulling experiments provide information about interactions in biomolecules that cannot be obtained by any other method. However, the reconstruction of the molecule’s free energy profile from the experimental data is still a challenge, in particular, for the unstable barrier regions. We propose a new method for obtaining the full profile by introducing a periodic ramp and using Jarzynski’s relation for obtaining equilibrium quantities from nonequilibrium data. Our simulated experiments show that this method delivers significant more accurate data than previous methods, under the constraint of equal experimental effort.
An Evaluative Framework For Assessing Information Management In Watershed Management: The Case Of The Grand River Conservation Authority (Ontario), Robert Scott Brown
An Evaluative Framework For Assessing Information Management In Watershed Management: The Case Of The Grand River Conservation Authority (Ontario), Robert Scott Brown
Theses and Dissertations (Comprehensive)
Watershed management has been rapidly evolving over the last 50 years. The current focus has been adaptive and ecosystem-based approaches to watershed management, redefining roles, responsibilities, and relationships of watershed organizations. While entire management models need to be heavily scrutinized, the practices and policies surrounding information are fundamentally important. Information forms the understanding and knowledge for watershed decision-making. Watershed organizations need to be critical of the policies and practices affecting their collection, storage, processing, analysis, monitoring, and reporting of data and information. Among the Conservation Authorities, the GRCA has developed a proficiency at information management, doing it as well as …
The Contribution Of Stewardship To Park Planning And Management In Ontario: A Study Of Bruce Peninsula And Georgian Bay Islands National Parks, Felicitas Egunyu
The Contribution Of Stewardship To Park Planning And Management In Ontario: A Study Of Bruce Peninsula And Georgian Bay Islands National Parks, Felicitas Egunyu
Theses and Dissertations (Comprehensive)
Parks Canada has adopted ecosystem-based management as a means of maintaining ecological integrity. However, ecosystems often extend beyond park boundaries. Where parks share boundaries with other government-protected areas, arrangements have often been made for cooperation. These arrangements usually result in mutual benefits for the protected areas involved. Where parks share boundaries with privately owned land, stewardship is one of the methods being used to implement conservation-based practices. This study investigated the extent to which stewardship contributes to park planning and management in Ontario using the Georgian Bay Islands and Bruce Peninsula National Parks as case studies. Results show that stewardship …
Forest Fires, Woodland Caribou And Land Use Policies In Northwestern Ontario (Rangifer Tarandus), Brian Frederick Kutas
Forest Fires, Woodland Caribou And Land Use Policies In Northwestern Ontario (Rangifer Tarandus), Brian Frederick Kutas
Theses and Dissertations (Comprehensive)
Woodland caribou (Rangifer tarandus caribou) are a threatened species in Ontario's boreal forest. Caribou require habitat that supports appropriate forage, including large areas of lichen rich forests. This research examines two dynamics that influence woodland caribou habitat in northwestern Ontario. These dynamics are forest fires and land use policies. The effects of forest fires are assessed quantitatively at both the ecosite and landscape scales within Woodland Caribou Provincial Park. Land use policy and management activities are evaluated using a case study and a policy analysis of protected area and forest management approaches to woodland caribou conservation in this region. Forest …
Regional Planning And British Columbia's Agricultural Land Reserve: A Case Study Of Land Use, Development And Policy Impacts In The Central Okanagan Valley, Danielle H. Noble
Regional Planning And British Columbia's Agricultural Land Reserve: A Case Study Of Land Use, Development And Policy Impacts In The Central Okanagan Valley, Danielle H. Noble
Theses and Dissertations (Comprehensive)
In North America, farmland is commonly targeted as the site of urbanization, because it is often the most easy to develop. British Columbia has been no exception. But British Columbia is unique in North American planning because it has imposed a comprehensive agricultural land reserve (ALR), now over thirty years old, to respond to agricultural land loss. Such an instrument can have important implications for land-use planning and for planning practice. This research documents some of the impacts of the ALR on planning while focusing on the Central Okanagan Valley as a case study region. The lessons of the Okanagan …
Impacts At The Coast: Climate Change Influences On Lake Huron's Water Levels At Oliphant (Ontario), Kevin Tupman
Impacts At The Coast: Climate Change Influences On Lake Huron's Water Levels At Oliphant (Ontario), Kevin Tupman
Theses and Dissertations (Comprehensive)
Since 1998, climate change induced low water levels in the Great Lakes have caused environmental and socioeconomic impacts along most of the Great Lakes' shorelines. According to recent climate change research involving different water level scenarios, climate change over the next century may continue to cause water levels in the Great Lakes to decline. Such impacts may include wider shorelines, drying of coastal wetlands, and navigation hazards that may result in increased dredging activities. These impacts will have a strong influence on new shoreline management policies and planning. To better understand potential future impacts, a specific methodology was developed to …
Temporal Variability In Nutrient Transport In A First-Order Agricultural Basin In Southern Ontario, Merrin L. Macrae
Temporal Variability In Nutrient Transport In A First-Order Agricultural Basin In Southern Ontario, Merrin L. Macrae
Theses and Dissertations (Comprehensive)
This thesis examines phosphorus and nitrate transport in a first-order agricultural catchment in Southern Ontario. Specific areas of concern relate to (1) long- and short-term temporal variability in nutrient export patterns, (2) the role of drainage tiles in annual nutrient export, (3) the effects of antecedent hydrologic conditions (AHC) on nutrient export patterns and (4) temporal variability in the nutrient retention in riparian buffer strips and streams. Temporal variability in hydrochemical export from the study basin over a two-year period is described and quantified and the importance of high magnitude events is highlighted. This is the first comprehensive study to …
Book Review Of Chromatography Of Natural, Treated And Waste Waters Edited By T. R. Crompton, John J. Johnston
Book Review Of Chromatography Of Natural, Treated And Waste Waters Edited By T. R. Crompton, John J. Johnston
United States Department of Agriculture Wildlife Services: Staff Publications
T. R. Crompton has accomplished a significant task, summarizing the literature (up to 1998) for the determination of organic and inorganic compounds in a variety of water substrates (surface/natural water, treated water, and waste water). Overall, the book is relatively easy to read; the manuscript produced by the author contains clear tables, figures, and font. The first chapter presents a brief overview of the techniques presented in the book. The author assumes that the reader has a general understanding of chromatography and the basic components of a chromatographic system. The remainder of the book is organized into chapters by chromatographic …
Prevalence Of Neurotoxic Clostridium Botulinum Type C In The Gastrointestinal Tracts Of Tilapia (Oreochromis Mossambicus) In The Salton Sea, P. P. Nol, T. E. Rocke, K. Gross, T. M. Yuill
Prevalence Of Neurotoxic Clostridium Botulinum Type C In The Gastrointestinal Tracts Of Tilapia (Oreochromis Mossambicus) In The Salton Sea, P. P. Nol, T. E. Rocke, K. Gross, T. M. Yuill
United States Department of Agriculture Wildlife Services: Staff Publications
Tilapia (Oreochromis mossambicus) have been implicated as the source of type C toxin in avian botulism outbreaks in pelicans (Pelecanus erythrorhynchos, Pelecanus occidentalis californicus) at the Salton Sea in southern California (USA). We collected sick, dead, and healthy fish from various sites throughout the Sea during the summers of 1999 through 2001 and tested them for the presence of Clostridium botulinum type C cells by polymerase chain reaction targeting the C1 neurotoxin gene. Four of 96 (4%), 57 of 664 (9%), and five of 355 (1%) tilapia tested were positive for C. botulinum type C …
Safety Of Brucella Abortus Strain Rb51 In Black Bears, Steven C. Olsen, Jack Rhyan, T. Gidlewski, Jesse Goff, W. C. Stoffregen
Safety Of Brucella Abortus Strain Rb51 In Black Bears, Steven C. Olsen, Jack Rhyan, T. Gidlewski, Jesse Goff, W. C. Stoffregen
United States Department of Agriculture Wildlife Services: Staff Publications
In two studies conducted from October 1999 to March 2000 and December 2000 to April 2001, adult black bears (Ursus americanus) were orally inoculated with 1.4–3.1X1010 colony-forming units (CFU) of Brucella abortus strain RB51 (SRB51, n=12) or 2 ml of 0.15 M NaCl solution (saline, n=11). We did not detect a difference (P>0.05) in antibody titers to SRB51 in serum obtained before vaccination, at 8 wk after vaccination, or at necropsy at 21 or 23 wk after vaccination between SRB51-vaccinated and nonvaccinated bears. The SRB51 vaccine strain was recovered from tissues obtained at …
การทดสอบสมมติฐานเกี่ยวกับความเป็นอิสระของตัวแบบล็อกการิทึมเชิงเส้นที่มีการแจกแจงพหุนาม, ประกาศิต สิงคะตีระ
การทดสอบสมมติฐานเกี่ยวกับความเป็นอิสระของตัวแบบล็อกการิทึมเชิงเส้นที่มีการแจกแจงพหุนาม, ประกาศิต สิงคะตีระ
Chulalongkorn University Theses and Dissertations (Chula ETD)
การวิจัยครั้งนี้มีวัตถุประสงค์ เพื่อเปรียบเทียบวิธีการทดสอบสมมติฐานเกี่ยวกับความเป็นอิสระของตัวแปรเชิงกลุ่ม 3 ตัวแปร ในตารางการณ์จร 3 ทาง ขนาด 2x2x2 และศึกษาความเป็นไปได้ที่จะนำวิธีการมอนติคาร์โลมาใช้แทนวิธีการทดสอบด้วยตัวสถิติอัตราส่วนภาวะน่าจะเป็น วิธีการทดสอบที่นำมาศึกษาเปรียบเทียบมี 3 วิธี ได้แก่ วิธีการทดสอบด้วยตัวสถิติอัตราส่วนภาวะน่าจะเป็น วิธีการทดสอบด้วยตัวสถิติของเซลเทอร์แมนและวิธีมอนติคาร์โล โดยวิธีการมอนติคาร์โลเป็นวิธีการทดสอบสมมติฐานที่ไม่อาศัยค่าวิกฤติของตัวสถิติทดสอบ แต่จะทำการเปรียบเทียบค่าสถิติที่คำนวณได้จากข้อมูลตัวอย่างที่ต้องการศึกษากับค่าสถิติที่คำนวณได้จากข้อมูลเทียมแต่ละชุดที่จำลองขึ้นโดยการสุ่มตัวอย่างซ้ำภายใต้ข้อกำหนดตามสมมติฐานว่าง เพื่อนำไปสู่การหาค่า P-value ผู้วิจัยได้ทำการศึกษาในแต่ละตัวแบบที่เป็นไปได้และเป็นตัวแบบที่มีรูปแบบปิดของค่าความถี่คาดหวัง เพื่อให้สามารถจำลองข้อมูลได้ถูกต้อง ซึ่งตัวแบบต่างๆ ประกอบด้วยตัวแบบที่เป็นอิสระอย่างสมบูรณ์ ตัวแบบความเป็นอิสระร่วม และตัวแบบความเป็นอิสระอย่างมีเงื่อนไข และได้กำหนดระดับความสัมพันธ์ให้กับตัวแปรร่วมที่มีความสัมพันธ์ร่วมกัน จากน้อยไปหามากคือ 0.25, 0.50 และ 0.75 ขนาดตัวอย่างที่ใช้คือ 40, 60, 80, 120, 160, 200 และ 240 และระดับนัยสำคัญที่ใช้คือ 0.05 และ 0.01 เกณฑ์ที่ใช้ในการเปรียบเทียบคือการพิจารณาความสามารถในการควบคุมความน่าจะเป็นของความผิดพลาดประเภทที่ 1 และ ค่าอำนาจการทดสอบ การวิจัยครั้งนี้ได้จำลองข้อมูลโดยกระทำซ้ำแบบเทคนิคมอนติคาร์โล (Monte Carlo simulation technique) จำนวน 500 ครั้ง ซึ่งในแต่ละครั้งจะกระทำซ้ำแบบมอนติคาร์โลอีก 500 ครั้ง เพื่อสร้างชุดข้อมูล 500 ชุด เพื่อคำนวณค่า P-value ของวิธีการทดสอบแบบมอนติคาร์โล ผลการวิจัยสามารถสรุปได้ดังนี้ วิธีการทดสอบทั้ง 3 วิธีสามารถควบคุมความน่าจะเป็นของความผิดพลาดประเภทที่ 1 ได้ในทุกสถานการณ์ วิธีการมอนติคาร์โลมีแนวโน้มที่จะให้ค่าอำนาจการทดสอบสูงที่สุด รองลงมาคือวิธีการทดสอบด้วยตัวสถิติอัตราส่วนภาวะน่าจะเป็น และวิธีการสอบด้วยตัวสถิติของเซลเทอร์แมน และโดยเฉพาะอย่างยิ่งในกรณีตัวอย่างขนาดเล็ก วิธีการมอนติคาร์โลจะมีค่าอำนาจการทดสอบสูงกว่าวิธีการอื่นอย่างชัดเจน ทั้งนี้เนื่องจากแนวคิดของวิธีการมอนติคาร์โลที่มีการจำลองข้อมูลเทียมหลายชุดภายใต้สมมติฐานว่างขึ้นมาพิจารณานั้นเสมือนเป็นการสร้างขอบเขตที่เป็นไปได้ของข้อมูลตามข้อกำหนดในสมมติฐานว่าง เพื่อเปรียบเทียบกับข้อมูลตัวอย่างที่ศึกษา จึงมีความถูกต้องมากกว่าการทดสอบสมมติฐานโดยทั่วไปซึ่งเป็นการเปรียบเทียบระหว่างค่าสถิติที่คำนวณได้กับค่าวิกฤติเพียงครั้งเดียว นอกจากนี้ยังพบว่าค่าอำนาจการทดสอบของวิธีการทดสอบทั้ง 3 วิธีแปรผันตามขนาดตัวอย่าง ระดับความสัมพันธ์ของตัวแปรร่วม และระดับนัยสำคัญ โดยสรุป ผู้วิจัยพบว่ามีความเป็นไปได้ที่จะนำเอาการทดสอบสมมติฐานด้วยวิธีการมอนติคาร์โลมาใช้ทดสอบสมมติฐานเกี่ยวกับความเป็นอิสระของตัวแบบล็อกการิทึมเชิงเส้น แทนการทดสอบทั้งสองวิธีดังกล่าวใน 3 ตัวแบบข้างต้นได้ โดยเฉพาะอย่างยิ่งในกรณีตัวอย่างขนาดเล็ก
Bird Depredation, James F. Glahn, D. Tommy King
Bird Depredation, James F. Glahn, D. Tommy King
United States Department of Agriculture Wildlife Services: Staff Publications
A survey of catfish producers by the United States Department of Agriculture, Centers for Epidemiology and Animal Health (CEAH) in 1996 indicated that the two primary sources of catfish losses in commercial operations were disease (45%) and wildlife (37%) (CEAH 1997a). A variety of avian and mammalian predators are amracred to aquaculture facilities in the United States (Parkhurs: er al. 1992) because ponds and open raceways provide a constant and readily accessible food supply for these animals. However, the mere presence of these predators arcund aquaculture faciliries does not necessarily mean that significant depredation problems are occurring. At catfish farms, …
Functional Feeding Responses Of Coyotes, Canis Latrans, To Fl Uctuating Prey Abundance Inthe Curlew Valley, Utah, 1977–1993 , Rebecca A. Bartel, Frederick F. Knowlton
Functional Feeding Responses Of Coyotes, Canis Latrans, To Fl Uctuating Prey Abundance Inthe Curlew Valley, Utah, 1977–1993 , Rebecca A. Bartel, Frederick F. Knowlton
United States Department of Agriculture Wildlife Services: Staff Publications
We investigated interactions between coyotes (Canis latrans Say, 1823) and prey in the Curlew Valley, Utah, by comparing prey abundances with prey consumption rates. Previous studies reported a cyclic trend in black-tailed jackrabbit (Lepus californicus Gray, 1837) density with a period of 10 years and >150-fold amplitude, as well as short-term fl uctuations among some rodent species that exceeded an 8-fold difference in amplitude over 2 years. Our results suggest changes in coyote diets mainly refl ect the fl uctuations in jackrabbit abundance. Prey switching to rodents during periods of low jackrabbit abundance also was evident. We used the initial …
Seasonal Activity Areas Of Coyotes In The Bear River Mountains Of Utah And Idaho, Glen F. Gantz, Frederick F. Knowlton
Seasonal Activity Areas Of Coyotes In The Bear River Mountains Of Utah And Idaho, Glen F. Gantz, Frederick F. Knowlton
United States Department of Agriculture Wildlife Services: Staff Publications
We studied the seasonal movement patterns and dispersal of coyotes (Canis latrans) in the Bear River Mountains of northern Utah and southern Idaho to determine whether coyotes in this montane region exhibit an altitudinal migration on a seasonal basis. We used 3 locational parameters to assess whether a seasonal altitudinal migration was evident, including overlap in seasonal activity areas, distance between harmonic mean centers of activity, and seasonal differences in mean elevations of locations. Winter and summer activity areas of every mature coyote overlapped, with mean distances between harmonic centers of seasonal activity of 1.5 km (range = 0.4–3.3 km). …