Feral hog distribution (Sus scrofa) has increased to 38 states due to high fecundity rates, an omnivorous diet, and translocation by humans; affecting various stakeholders. To assess stakeholder attitudes and feral hog distribution in the United States and within Mississippi, selfministered mail questionnaires were sent to district level state wildlife biologists nationwide (n = 614) and to Mississippi Farm Bureau county presidents (FBCP; n = 79). I used the Wildlife Stakeholder Acceptance Capacity theory to assess what factors (e.g., species presence, perceived density, stakeholder land usage, risk belief, attitudes toward the species) influenced stakeholder preferences for a specific future population trend (i.e., increase or decrease). Wildlife biologists were influenced by attitudes and occupational risk beliefs. Influential factors of FBCP attitudes could not be assessed because no producers wanted an increase in future hog populations.

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The topic of this thesis is the recognition and detection of moving object and persons in video sequence and in the static image. Designed application uses the combination of background model for movement detection, histograms of oriented gradients method for person recognition and Lucas-Kanade method for object tracking.

No description available.

Leaf area index (LAI), litter production and understory light levels of Myrica cergera shrub thickets were assessed on Hog Island, Virginia to quantify spatial and seasonal variations in leaf area and light attenuation among four thickets representing a successional chronosequence and compare methods of estimating LA1 in shrub- dominated systems. Seasonal LA1 estimates were made seven times throughout the year with a portable integrating radiometer (Li-Cor LAI-2000) and three times by measurement of photosynthetically active radiation (PAR) and use of the Beer-Larnbert law. Leaf area index was also estimated through leaf litter collection and use of allometric relationships between stem diameter and leaf area. The oldest of the four thickets had the lowest LA1 and litter production throughout the year. Peak LA1 measurements with the portable integrating radiometer ranged from 2.0 ± 0.2 to 4.0 ± 0.3 for the oldest and youngest thickets, respectively which appear to be substantial underestimates of the actual values. According to annual litterfall, LA1 ranged from 4.1 ± 0.5 for the oldest thicket to 10.2 ± 0.4 for a 20 year old thicket. Leaf area index varied from 6.4 ± 0.2 for the oldest thicket to 1 1.4 ± 2.1 for the 40 year old thicket according to the allometric relationships, which may overestimate LA1 in stands with many large stems. The high light attenuation by the shrub canopy and heavy litterfall may contribute to the low diversity within thicket canopies by inhibiting germination and growth of other species. The study demonstrates that these low diversity shrub thickets have a higher LA1 and litter production, and thus higher potential for primary productivity, than many temperate forested systems and that stand age may be the major determinant of productivity.

Background: Previous studies testing the association between the built environment and walking behaviour have been largely cross-sectional and have yielded mixed results. This study reports on a natural experiment in which changes to the built environment were implemented at a university campus in Hong Kong. Longitudinal data on walking behaviours were collected using surveys, one before and one after changes to the built environment, to test the influence of changes in the built environment on walking behaviour. / Experimental design: Changes to land use, campus bus services, pedestrian network, and population density were collected from campus maps, the university developmental office, and field surveys. Motivational data towards walking were collected at baseline in March 2012 (n=198) and after changes to the built environment from the same cohort of subjects in December 2012 (n=169) using a Theory of Planned behaviour (TPB) based questionnaire. Walking behaviours were objectively measured by a walking-oriented diary in the two points of survey. / Methods: Geographic information system (GIS) was used to map the changes to the built environment and walking behaviours. Walking outcomes were measured in terms of: i) walking distance, ii) destination-oriented walking, and iii) walked altitude range. Multivariate linear regression models were used to test for associations between changes to the built environment and walking behaviours. A walking accessibility measure that allows comparison of perception and reality of walking in this hilly community is developed by GIS. Structural equation modelling is used to test the causal relationship between the motivational factors, including the salient beliefs, attitude, perceived behaviour control (PBC), subjective norm (SN), intention, and walking outcomes. / Results: We found that i) changes to the built environment lead to changes in walking behaviours. Specifically, Greater pedestrian network connectivity predicted longer walking distances and an increased likelihood of walking as a means of transportation. The increased use of recreational (vs. work) buildings, largely located at mid-range altitudes, as well as increased population density predicted greater walking distances. Having a greater density of work buildings at lower altitudes deceased subjects’ walked altitude range, while having more bus services and a greater population density encouraged people to increase their walked altitude range; / ii) We developed a practical walking accessibility measure, which was used to visualize the geography of the difference between the perception and reality of walking in this hilly environment for use by urban planners and public health practitioners. We practically addressed the issues in calculating accessibility measures in the present context arise primarily from problems with data quality, three-dimensional pedestrian network modelling and the adequacy of accessibility methods for describing and predicting walking behaviour; and / ii) We found that PBC and attitude were the major determinants of intention, while SN did not exert a significant effect in prediction of intention and walking behaviour. Compared with the baseline survey, PBC has an increased effect on the intention in the follow-up survey. This study partially supports the proposed causal nature of the TPB as a framework for investigating the influence of changes to the built environment on walking behaviours. / 研究背景：现有建成环境与步行行为关系的研究以社区横向比较为主，很难得到一致结论。本论文利用一个建成环境的自然实验，跟踪同一批样本，在建成环境改变之前后，分别采集一次数据，以探索建成环境变化对步行行为的影响。 / 实验设计：建成环境变化发生在香港一所大学校园，研究者收集了包括土地利用及建筑功能、校园巴士服务、步行径、人口密度数据等变化数据。我们根据计划行为理论设计了问卷，进行了样本感知变化的对比研究；同时，利用修订的侧重于步行的出行日志，进行步行行为的数据采集。第一次数据采集在建成环境变化前的2012年3月进行，样本数量为198人；针对同一批样本的第二次数据采集在建成环境变化后的2012年12月进行，剩余169人参加。 / 方法：我们利用地理信息系统（GIS）客观度量建成环境并进行步行行为的地图绘制。步行行为的变化被量化为：i) 步行距离，ii) 以步行为主的出行所占的比例，iii) 步行所跨越的高程的变化（实验区为丘陵地貌）。通过多元线性回归模型，我们分析客观度量的建成环境变化对步行行为的影响。实验过程中，我们发现样本在步行出行选择时对丘陵地貌的感知存在空间差异，因此，我们利用GIS 建立了步行可达性模型，以度量这种感知与真实的差异。通过结构方程模型，我们分析了计划行为理论问卷所得的数据。 / 结果：我们发现i) 建成环境的改变导致了步行行为的改变。具体来讲，提高步行径的连接度，可以鼓励人们选择步行并增加他们的步行距离；建成环境中增加的生活功能的建筑，由于大多集中与校园中部，增加了样本的步行距离；人口密度的增加也提高了人们选择步行的可能性并增加了步行距离。影响样本步行所跨越高度变化的因素有在低海拔处新建的教学大楼、调整的巴士服务以及人口密度的变化。 / ii) 我们开发的步行可达性度量，以地图可视化的方式呈现了样本对丘陵地貌社区的感知与真实的空间差异。在此过程中，我们解决了针对步行行为的数据质量、三维步行径建模分析、以及实用可达性建模等问题。 / iii) 在计划行为理论模型的分析中，我们发现认知行为控制和态度是步行行为意向的决定因素，而行为主观规范的影响并不明显。相对于建成环境变化前，认知行为控制对行为意图的影响程度有所增加。该研究证明计划行为理论可以应用于建成环境变化对步行行为影响的研究中。 / Sun, Guibo = 建成环境变化对步行行为影响之探索 : 以发生在香港一所大学校园的自然实验为例 / 孙贵博. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2014. / Includes bibliographical references (leaves 79-88). / Abstracts also in Chinese. / Title from PDF title page (viewed on 03, November, 2016). / Sun, Guibo. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only. / Detailed summary in vernacular field only.

No description available.

A study was conducted in 2004 and 2005 to determine the effect of liquid hog manure fertilization on greenhouse gas emissions from the surface of a grassland pasture in south-eastern Manitoba. The objectives of this research were to determine the effects of manure application, itstiming and soil moisture on greenhouse gas emissions from pasture soil, cattle dung and urine patches. Nitrous oxide (N2O), methane (CH4) and carbon dioxide (CO2) emissions were determined from grassland soil surface, and from cattle dung and artificial urine patches. Liquid hog manure treatments were no manure (Control); 153 kg ha-1 of available-nitrogen (N) (two year average) in spring (Spring); and 149 kg ha-1 as half-rate applications in fall and spring (Split). Four field experiments were conducted on grassland plots. The static-vented chamber technique was used to estimate gas emission rates. Two of the experiments focused on the effects of manure application timing and soil moisture on greenhouse gas emissions from the grassland soil surface. The other two experiments focused on the effects of manure application and soil moisture on greenhouse gas emissions from cattle dung and artificial urine patches. Fresh cattle dung was collected from steers grazing adjacent pastures receiving the same three manure treatments. Artificial cattle urine treatments were generated by converting blood urea concentrations of the steers into urine-N concentrations. Manure application increased (P≤0.01) cumulative N2O emissions from the grassland soil surface with Control, Split and Spring treatments averaging 7, 43 and 120 mg N2O-N m-2, respectively. Of the two manure treatments, the Spring treatment emitted higher (P≤0.10) N2O emissions than the Split treatment. Soil moisture was a major factor influencing the quantity and type of greenhouse gas emissions, with saturated areas emitting CH4 during warm periods, whereas drier areas emitted N2O. Nitrous oxide emissions from these dry areas were higher in manure-treated plots. Spring application increased root density by 45% in the top 5 cm of soil compared to the Control. An increase in soil organic carbon with root density may offset any increase in greenhouse gas emissions caused by manure treatment. Cattle dung from Split and Spring treatments had higher cumulative N2O emissions (30 and 82 mg N2O-N m-2, respectively) compared to dung from Control pastures (6 mg N2O-N m-2) over two study years. Dung from the Spring treatment emitted more N2O (P≤0.01) than the other two treatments. All cattle dung patches emitted CH4 after deposition though unaffected by manure treatment. Artificial urine having highest N concentration had greater (P≤0.05) cumulative N2O emissions (690 mg N2O-N m-2) than urine with the lowest N concentration (170 mg N2O-N m-2). Drier soil locations emitted more N2O from cattle dung and artificial urine patches than wetter areas. This study demonstrated that Split application of liquid hog manure to grassland emitted less N2O than a complete application in spring. Moisture greatly affected the location of N2O and CH4 emissions. Drier areas emitted more N2O than wetter ones. Particularly, the findings indicate a need to assess grassland on periodically saturated soils as sources rather than sinks for CH4. Application of manure increased greenhouse gas emissions from cattle dung and urine patches with urine potentially having the greatest impact because of their higher emissions of N2O. An increase in root growth seems to offset greenhouse gas emissions from manure application.

This thesis examines how the non-Newtonian characteristics of liquid hog manure affect the flow conditions within a steady-flow anaerobic digester. There are three main parts to this thesis. In the first part of this thesis, the physical properties of liquid hog manure and their variation with temperature and solids concentration are experimentally determined. Naturally¬¬-settled manure sampled from an outdoor storage lagoon is studied, and density, viscosity, and particle size distribution are measured. Hog manure with total solids concentrations of less than 3.6% exhibits Newtonian behaviour; manure between 3.6% and 6.5% total solids is pseudoplastic, and fits the power law; manure with more than 6.5% total solids exhibits non-Newtonian and time-dependent characteristics. The second part of this thesis investigates the flow of Newtonian and non-Newtonian fluids—represented by tap water and xanthan gum solution, respectively—within four lab-scale reactor geometries, using residence time distribution (RTD) experiments. The effect of reactor geometry, flow rate, and fluid viscosity are evaluated. In the third part of this thesis, flow conditions within lab-scale and pilot-scale anaerobic digester reactors are simulated using three-dimensional modeling techniques. The RTDs of lab-scale reactors as predicted by the 3D numerical models compare well to the experimental results. The 3D models are also validated using data from particle image velocimetry (PIV) experiments. Finally, the viscous properties of liquid hog manure at 3% and 8% total solids are incorporated into the models, and the results are evaluated.

Feral pigs, European wild boars and their crosses are ubiquitous and found in all ecological zones from Florida to California. These introduced animals are recorded in 39 US states and four Canadian provinces. Texas currently has an estimated population of 1-4 million pigs with the potential to exceed 4 million based on suitable habitat estimates. Feral pigs can modify local flora and fauna and cause significant physical damage with their rooting activities. They can also reintroduce parasites and pathogens to previously parasite and pathogen free herds of domestic cattle, horses, sheep, and goats. The two overarching objectives of this research were to determine what role feral pigs have in the maintenance and possible distribution of fleas, lice, and ticks common to the three wildlife districts; and if they serve as bridging hosts for the same (or other) arthropods and their natural hosts. The supporting objectives were to establish host records of fleas, lice, and ticks parasitizing feral pigs; determine species assemblies within each of the three wildlife districts; and to compare species assemblies among the wildlife districts. Feral pigs (564) were taken from June 2008 to March 2011 using box, corral, and panel traps in three wildlife districts. Two hundred fifty six fleas, Pulex porcinus (Jordan and Rothschild), were collected from all gender and age classes of feral pigs at the South Texas Plains wildlife district. No fleas were collected at either the Hill Country or Post Oak Savannah wildlife districts. This is the first report of these fleas on feral pigs. Lice and ticks were collected from all gender and age classes of feral pigs from all sample sites. Only hog lice, Haematopinus suis, were collected at all three sample sites. Seven species of ticks were collected from the three sites: Amblyomma americanum, A. cajennense, A. maculatum, Dermacentor albipictus, D. halli, D. variabilis, and Ixodes scapularis. Amblyomma cajennense was collected only at the South Texas Plains sample site; A. americanum and I. scapularis were collected only at the Hill Country and Post Oak sample sites. This study reports that feral pigs are serving as hosts for one species of flea, one species of lice and seven species of ticks common to Texas.