排序方式： 共有6条查询结果，搜索用时 156 毫秒
1
1.
Populations of New England cottontails (Sylvilagus transitionalis) have declined substantially in recent decades in response to habitat loss and fragmentation. Among some remnant populations, cottontails occupy small patches of thicket habitat where they experience high mortality rates as a consequence of limited food during winter. This limitation causes rabbits to forage away from cover where they are exposed to predators. Although conservation efforts are emerging to reverse the decline of New England cottontails, most are directed toward improving long-term viability by increasing the abundance of suitable habitats. Such efforts do little to improve the short-term survival of remaining cottontails. To address this immediate need, we evaluated the use of supplemental food as an approach to improve overwinter survival rates. We speculated that by positioning feeders in close proximity to escape cover, rabbits would be less vulnerable to predators. We evaluated this approach using eastern cottontails (Sylvilagus floridanus) as a research surrogate because this species is readily available and has similar habitat requirements to New England cottontails. Transmitter-equipped eastern cottontails were randomly assigned to either a fed or unfed group. Remotely-triggered cameras were also used to gauge use of feeders by cottontails and visits by other species. Winter survival rates were substantially greater for fed rabbits (70%) than for unfed rabbits (32%). Cameras revealed that rabbits were the most frequent consumer and that there was only limited carnivore activity near feeders. We conclude that supplemental feeding may improve survival of remaining New England cottontails as efforts to increase habitat availability continue to develop. 相似文献
2.
R M Weinshilboum F A Raymond L R Elveback W H Weidman 《Science (New York, N.Y.)》1973,181(103):943-945
Dopamine-beta-hydroxylase activity is released into the blood with catecholamines from the adrenal medulla and sympathetic nerves. This enzyme activity has been measured in the blood of 317 normal children and 227 normal adults. A significant sibling-sibling correlation of serum dopamine-beta-hydroxylase values was found in the 94 sibling pairs tested. Frequency distributions of serum enzyme values in both children and adults suggest the existence of two populations with regard to serum activity of this enzyme. 相似文献
3.
4.
Mark Rishniw BVSC MS Joyce Weidman DVM William J. Hornof DVM MS 《Veterinary radiology & ultrasound》1998,39(3):193-19
Hydrothorax was identified in a 14-year-old Siamese cat with a pre-existent perinephric pseudocyst. The pleural fluid was classified as a low-protein transudate. Intrapseudocystic scintigraphy confirmed a direct communication between the pseudocyst and the pleural space. The hydrothorax resolved following pseudocystectomy and unilateral nephrectomy, demonstrating that the psendocyst caused the hydrothorax. 相似文献
5.
Methé BA Nelson KE Eisen JA Paulsen IT Nelson W Heidelberg JF Wu D Wu M Ward N Beanan MJ Dodson RJ Madupu R Brinkac LM Daugherty SC DeBoy RT Durkin AS Gwinn M Kolonay JF Sullivan SA Haft DH Selengut J Davidsen TM Zafar N White O Tran B Romero C Forberger HA Weidman J Khouri H Feldblyum TV Utterback TR Van Aken SE Lovley DR Fraser CM 《Science (New York, N.Y.)》2003,302(5652):1967-1969
The complete genome sequence of Geobacter sulfurreducens, a delta-proteobacterium, reveals unsuspected capabilities, including evidence of aerobic metabolism, one-carbon and complex carbon metabolism, motility, and chemotactic behavior. These characteristics, coupled with the possession of many two-component sensors and many c-type cytochromes, reveal an ability to create alternative, redundant, electron transport networks and offer insights into the process of metal ion reduction in subsurface environments. As well as playing roles in the global cycling of metals and carbon, this organism clearly has the potential for use in bioremediation of radioactive metals and in the generation of electricity. 相似文献
6.
Gardner MJ Bishop R Shah T de Villiers EP Carlton JM Hall N Ren Q Paulsen IT Pain A Berriman M Wilson RJ Sato S Ralph SA Mann DJ Xiong Z Shallom SJ Weidman J Jiang L Lynn J Weaver B Shoaibi A Domingo AR Wasawo D Crabtree J Wortman JR Haas B Angiuoli SV Creasy TH Lu C Suh B Silva JC Utterback TR Feldblyum TV Pertea M Allen J Nierman WC Taracha EL Salzberg SL White OR Fitzhugh HA Morzaria S Venter JC Fraser CM Nene V 《Science (New York, N.Y.)》2005,309(5731):134-137
We report the genome sequence of Theileria parva, an apicomplexan pathogen causing economic losses to smallholder farmers in Africa. The parasite chromosomes exhibit limited conservation of gene synteny with Plasmodium falciparum, and its plastid-like genome represents the first example where all apicoplast genes are encoded on one DNA strand. We tentatively identify proteins that facilitate parasite segregation during host cell cytokinesis and contribute to persistent infection of transformed host cells. Several biosynthetic pathways are incomplete or absent, suggesting substantial metabolic dependence on the host cell. One protein family that may generate parasite antigenic diversity is not telomere-associated. 相似文献
1