Linking monitoring and intervention for improved management of tigers in the Sundarbans of Bangladesh     

Adam C.D. Barlow  Md. Ishtiaq U. Ahmed  Md. Mizanur Rahman 《Biological conservation》2008,141(8):2032-2040

Baseline data on distribution and abundance of tigers in the Sundarbans is required to identify problem areas and evaluate management strategies. This paper outlines a khal (creek) bank survey of track set frequency throughout the Bangladesh Sundarbans to aid formulation of a management-driven monitoring program. Three teams of two observers surveyed a total of 1 201 km of waterways throughout the Sundarbans, recording 1 338 tiger track sets. These sets became unrecognizable as tiger sign after a mean 10 days (range 6-14). Proportion of detectable sign recorded was 0.91. Mean (±standard error) sample unit track frequency was 1.12 ± 0.86 track sets/km of khal. The mean coefficient of variance in sample unit track rate, estimated by multiple counts of six sample units, was 0.21 (range 0.06-0.34). Track frequency generally increased from northeast to southwest. Four sample units (6%) had signs of reproduction, with a mean litter size of 1.75 ± 0.5. Monte Carlo simulation suggests a monitoring program of one complete survey every two years will have power of 0.8 (α = 0.2), to detect track frequency declines of ?19% and increases of ?17%. We recommend this monitoring scheme be implemented on the Indian side of the Sundarbans to provide a standard assessment of the tiger population and to form the basis for setting management objectives and evaluating transboundary conservation initiatives.  相似文献   

基于数字化植物表型平台（D3P）的田间小麦冠层光截获算法开发     

刘守阳  金时超  郭庆华  朱艳  Baret Fred 《智慧农业(中英文)》2020,2(1):87-98

冠层光截获能力是反映作物品种间差异的重要功能性状，高通量表型冠层光截获对提高作物改良效率具有重要意义。本研究以小麦为研究目标，利用数字化植物表型平台（D3P）模拟生成了100种冠层结构不同的小麦品种在5个生育期的三维冠层场景，记录了从原始冠层结构中提取的绿色叶面积指数（GAI）、平均倾角（AIA）和散射光截获率（FIPAR_dif）信息作为真实值,进一步利用上述三维小麦场景开展了虚拟的激光雷达（LiDAR）模拟实验，生成了对应的三维点云数据。基于模拟的点云数据提取了其高度分位数特征（H）和绿色分数特征（GF）。最后，利用人工神经网络（ANN）算法分别构建了从不同LiDAR点云特征（H、GF和H+GF）输入到FIPAR_dif、GAI和AIA的反演模型。结果表明，对于GAI、AIA和FIPAR_dif，预测精度从高到低对应的点云特征输入为GF+H > H > GF。由此可见，H特征对提高目标表型特性的估算精度起到了重要作用。输入GF + H特征，在中等测量噪音（10%）情况下，FIPAR_dif和GAI的估算均获得了满意精度，R²分别为0.95和0.98，而AIA的估算精度（R²=0.20）还有待进一步提升。本研究基于D3P模拟数据开展，算法的实际表现还有待通过田间数据进一步验证。尽管如此，本研究验证了D3P协助表型算法开发的能力，展示了高通量LiDAR数据在估算田间冠层光截获和冠层结构方面的较高潜力。  相似文献   

Frost response in wheat and early detection using proximal sensors     

James G. Nuttall  Eileen M. Perry  Audrey J. Delahunty  Garry J. O'Leary  Kirsten M. Barlow  Ashley J. Wallace 《Journal of Agronomy and Crop Science》2019,205(2):220-234

Frost can significantly reduce production of field crops grown in Mediterranean‐type environments, where significant economic losses for Australian wheat occur annually. If non‐destructive sensors could make rapid, spatial assessment of frost damage, this could limit economic losses through timely management decisions. This paper reports on a methodology for imposing frost treatments to wheat under field conditions and the utility of canopy reflectance data for detecting early crop damage. Purpose‐built chambers using stepped additions of dry ice allowed for a range of frost scenarios to be tested when applied at wheat heading and anthesis. For frost treatments applied at anthesis, grain number and yield were reduced by 8.8% and 7.2%, respectively, for every degree Celsius below zero (down to ?4°C). This effect was additive over two consecutive nights. For cold load equivalent, there was a 2.2% and 1.9% reduction in grain number and yield, respectively, per °C hr (below 0°C). For wheat, spectral indices PRI and NDVI (reflectance) and FRF_G and SFR_G (fluorescence) showed significant relationships, with cold load applied for heading treatments. Next steps include targeting frost intensities equivalent to cold loads between 20 and 80°C hr and testing the utility of these proposed indices in a commercial paddock setting.  相似文献   

TSE pathogenesis in cattle and sheep     

van Keulen LJ  Bossers A  van Zijderveld F 《Veterinary research》2008,39(4):24

Many studies have been undertaken in rodents to study the pathogenesis of transmissible spongiform encephalopathies (TSE). Only a few studies have focused on the pathogenesis of bovine spongiform encephalopathy (BSE) and scrapie in their natural hosts. In this review, we summarize the most recent insights into the pathogenesis of BSE and scrapie starting from the initial uptake of TSE agents and crossing of the gut epithelium. Following replication in the gut-associated lymphoid tissues (GALT), TSE agents spread to the enteric nervous system (ENS) of the gut. Infection is then carried through the efferent fibers of the post-ganglionic neurons of the parasympathetic and sympathetic nervous system to the pre-ganglionic neurons in the medulla oblongata of the brain and the thoracic segments of the spinal cord. The differences between the pathogenesis of BSE in cattle and scrapie in sheep are discussed as well as the possible existence of additional pathogenetic routes.  相似文献   

种公鸡的饲养与选择     

Fred H．Kao 《中国家禽》2008,30(10):36-37

1 种公鸡的管理目标 为提高种公鸡的利用率与孵化率,良好的种公鸡管理不可缺少,种公鸡的管理目标包括:提高下代孵化率与整齐度;采取良好的农场管理与生物安全措施以尽量增加下代总数.  相似文献   

Histological observations of bovine tuberculosis in lung and lymph node tissues from British deer     

Johnson LK  Liebana E  Nunez A  Spencer Y  Clifton-Hadley R  Jahans K  Ward A  Barlow A  Delahay R 《Veterinary journal (London, England : 1997)》2008,175(3):409-412

Deer are recognized as hosts of Mycobacterium bovis and assessing the role of wild cervids in perpetuating tuberculosis among cattle has motivated extensive research on several continents. In this paper, the histopathology of lymph node and lung tuberculous granulomas in M. bovis positive British deer is presented. The overall aim was to seek further insights into the potential for onward transmission from infected deer to other species, including cattle. Samples were obtained from an extensive survey of wild mammals in South-West England and from statutory tuberculosis surveillance. M. bovis culture-positive samples were characterised microscopically as to their stage of lesion advancement, number of acid-fast bacilli and granuloma encapsulation. Seventy percent of the deer developed granulomas containing far greater numbers of M. bovis bacilli than typically reported in cattle. Red and fallow deer had the largest number of poorly encapsulated granulomas often containing many hundreds of bacilli. The results are consistent with infected wild British deer being a potential source of environmental contamination and onward transmission to other species. However, further work on levels of bacillary shedding is required before this can be confirmed.  相似文献   

Landscape,fire and habitat: which features of recently burned heathland influence site occupancy of an early successional specialist?     

Felicia Pereoglou  Christopher MacGregor  Sam C. Banks  Jeff Wood  Fred Ford  David B. Lindenmayer 《Landscape Ecology》2016,31(2):255-269

  相似文献   

Failure mode and bending moment of canine pancarpal arthrodesis constructs stabilized with two different implant systems     

Wininger FA  Kapatkin AS  Radin A  Shofer FS  Smith GK 《Veterinary surgery : VS》2007,36(8):724-728

Objective— To compare failure mode and bending moment of a canine pancarpal arthrodesis construct using either a 2.7 mm/3.5 mm hybrid dynamic compression plate (HDCP) or a 3.5 mm dynamic compression plate (DCP).
Study Design— Paired in vitro biomechanical testing of canine pancarpal arthrodesis constructs stabilized with either a 2.7/3.5 HDCP or 3.5 DCP.
Sample Population— Paired cadaveric canine antebrachii (n=5).
Methods— Pancarpal arthrodesis constructs were loaded to failure (point of maximum load) in 4-point bending using a materials-testing machine. Using this point of failure, bending moments were calculated from system variables for each construct and the 2 plating systems compared using a paired t-test. To examine the relationship between metacarpal diameter and screw diameter failure loads, linear regression was used and Pearson' correlation coefficient was calculated. Significance was set at P <.05.
Results— HDCP failed at higher loads than DCP for 9 of 10 constructs. The absolute difference in failure rates between the 2 plates was 0.552±0.182 N m, P =.0144 (95% confidence interval: −0.58 to 1.68). This is an 8.1% mean difference in bending strength. There was a significant linear correlation r=0.74 ( P -slope=.014) and 0.8 ( P -slope=.006) between metacarpal diameter and failure loads for the HDCP and 3.5 DCP, respectively.
Conclusion— There was a small but significant difference between bending moment at failure between 2.7/3.5 HDCP and 3.5 DCP constructs; however, the difference may not be clinically evident in all patients.
Clinical Relevance— The 2.7/3.5 HDCP has physical and mechanical properties making it a more desirable plate for pancarpal arthrodesis.  相似文献   

The effect of hemolysis on plasma antithrombin activity as determined by a chromogenic method     

van der Merwe L  Reyers F 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2007,36(1):55-59

BACKGROUND: The concentration of free hemoglobin (Hgb) in plasma can markedly affect the outcome of laboratory tests by interfering with the spectrophotometric absorbance of biochemical tests read at wavelengths within the absorbance range of Hgb (400-440 nm). Little is known about the effects of hemoglobinemia on antithrombin (AT) activity in human plasma samples, and we are unaware of data for canine plasma samples. OBJECTIVES: The objective of this study was to determine the degree of interference by Hgb on plasma AT activity and to determine if the interference is proportional to the concentration of plasma Hgb. METHODS: Two pools of test plasma, designated AT100 and AT70, were prepared. Hemolysate was prepared by washing and freeze-thawing packed red cells in a small volume of saline, followed by collection of the filtrate. Solutions of decreasing Hgb concentration were prepared and added to the test plasma pools to create a series of samples with final calculated and measured Hgb concentrations of 0, 0.5, 1.5, 2.5, 3.5, 4.5, and 5.5 g/L. AT activity, expressed as a percentage of normal human plasma, was determined using a functional chromogenic assay. RESULTS: Increasing concentrations of Hgb resulted in a linear decrease in AT activity. Using linear regression analysis on the 70% and 100% plasma pools, the slopes for samples containing <1.5 g Hgb/L were not significantly different from zero. Slopes for samples containing Hgb concentrations >or=1.5 g/L were significantly (P > .0001) different from zero for both plasma pools, indicating interference with the assay. CONCLUSIONS: The results of this study suggest it may be possible, using a conversion equation, to accurately determine AT activity in hemolyzed samples, facilitating evaluation of coagulation status in patients with intravascular hemolysis.  相似文献   

The Use of Colonic Irrigation to Control Fecal Incontinence in Dogs With Colostomies     

Fred A. Williams  JR  DVM  Ronald M. Bright  DVM  MS  Diplomate ACVS    Gregory B. Daniel  DVM  MS  Diplomate ACVR    Kevin A. Hahn  DVM  PhD    Steve A. Patton  DVM  MS  Diplomate ACVP 《Veterinary surgery : VS》1999,28(5):348-354

OBJECTIVE: To determine if once-daily colonic irrigation results in fecal continence for a 24-hour period in dogs with colostomies and if colonic volume increased in response to the irrigation. STUDY DESIGN: A prospective controlled experimental study. ANIMALS: Four intact male and one intact female mixed breed dogs. MATERIALS: All dogs received left end-on paralumbar colostomies. Four dogs received once-daily colonic irrigation for 8 weeks, whereas the control dog did not. Daily fecal weights were recorded for the length of the study in all dogs. Barium enema studies and volumetric studies were used to determine colonic volumes. RESULTS: Daily fecal weights were significantly decreased in treatment dogs compared with the control dog. Colonic volume increased in irrigated dogs in response to daily irrigation over the 8 week period of the study. CONCLUSIONS: Colonic irrigation resulted in significantly decreased fecal production over a 24-hour period. Therefore management of dogs with colostomies would be more practical and cost effective. It did not result in complete fecal continence in this study. Further clinical studies are indicated to determine if longer periods of irrigation would result in complete continence.  相似文献