What size is a biologically relevant landscape?     

Heather Bird Jackson  Lenore Fahrig 《Landscape Ecology》2012,27(7):929-941

The spatial extent at which landscape structure best predicts population response, called the scale of effect, varies across species. An ability to predict the scale of effect of a landscape using species traits would make landscape study design more efficient and would enable landscape managers to plan at the appropriate scale. We used an individual based simulation model to predict how species traits influence the scale of effect. Specifically, we tested the effects of dispersal distance, reproductive rate, and informed movement behavior on the radius at which percent habitat cover best predicts population abundance in a focal area. Scale of effect for species with random movement behavior was compared to scale of effect for species with three (cumulative) levels of information use during dispersal: habitat based settlement, conspecific density based settlement, and gap-avoidance during movement. Consistent with a common belief among researchers, dispersal distance had a strong, positive influence on scale of effect. A general guideline for empiricists is to expect the radius of a landscape to be 4?C9 times the median dispersal distance or 0.3?C0.5 times the maximum dispersal distance of a species. Informed dispersal led to greater increases in population size than did increased reproductive rate. Similarly, informed dispersal led to more strongly decreased scales of effect than did reproductive rate. Most notably, gap-avoidance resulted in scales that were 0.2?C0.5 times those of non-avoidant species. This is the first study to generate testable hypotheses concerning the mechanisms underlying the scale at which populations respond to the landscape.  相似文献   

The effects of yohimbine on the pharmacokinetic parameters of detomidine in the horse     

Knych HK  Steffey EP  Stanley SD 《Veterinary anaesthesia and analgesia》2012,39(3):221-229

ObjectiveTo describe the pharmacokinetics of detomidine and yohimbine when administered in combination.Study designRandomized crossover design.AnimalsNine healthy adult horses aged 9 ± 4 years and weighing of 561 ± 56 kg.MethodsThree dose regimens were employed in the current study. 1) 0.03 mg kg^?1 detomidine IV (D), 2) 0.2 mg kg^?1 yohimbine IV (Y) and 3) 0.03 mg kg^?1 detomidine IV followed 15 minutes later by 0.2 mg kg^?1 yohimbine IV (DY). Each horse received all three dose regimens with a minimum of 1 week in between subsequent regimens. Blood samples were obtained and plasma analyzed for detomidine and yohimbine concentrations by liquid chromatography-mass spectrometry. Data were analyzed using both non-compartmental and compartmental analysis.ResultsThe maximum measured detomidine concentrations were 76.0 and 129.9 ng mL^?1 for the D and DY treatments, respectively. Systemic clearance and volume of distribution of detomidine were not significantly different for either treatment. There was a significant increase in the maximum measured yohimbine plasma concentrations from Y (173.9 ng mL^?1) to DY (289.8 ng mL^?1). Both the Cl and V_d for yohimbine were significantly less (6.8 mL minute^?1 kg^?1 (Cl) and 1.7 L kg^?1 (V_d)) for the DY as compared to the Y treatments (13.9 mL minute^?1 kg^?1 (Cl) and 2.7 L kg^?1 (V_d)). Plasma concentrations were below the limit of quantitation (0.05 and 0.5 ng mL^?1) by 18 hours for both detomidine and yohimbine.Conclusion and clinical relevanceThe Cl and V_d of yohimbine were affected by prior administration of detomidine. The elimination half life of yohimbine remained unaffected when administered subsequent to detomidine. However, the increased plasma concentrations in the presence of detomidine has the potential to cause untoward effects and therefore further studies to assess the physiologic effects of this combination of drugs are warranted.  相似文献   

Critical care monitoring considerations for the diabetic patient     

Connally HE 《Clinical Techniques in Small Animal Practice》2002,17(2):73-78

Diabetes mellitus (DM) is a common endocrine disease encountered in the emergency and critical care setting. The diabetic Ketoacidotic (DKA) animal represents an extreme of the DM patient with regard to hyperglycemia and acid-base and electrolyte derangements. Prompt diagnosis of DKA in a critical patient and rapid initiation of appropriate therapy are necessary for a positive outcome. The steps of treatment, in order of importance, include initiation of intravenous fluid therapy, insulin therapy, electrolyte replacement, and reversal of the metabolic acidosis. The main goals of therapy--including correction of dehydration, electrolyte abnormalities and acidosis via aggressive fluid therapy with electrolyte supplementation and correction of ketoacidosis and hyperglycemia via initiation of insulin therapy--can be achieved if these steps are followed. Because of the severity of metabolic alterations in the DKA animal, frequent and careful monitoring are paramount because they will allow the clinician to tailor treatment to each case.  相似文献   

Detection of Streptococcus equi subspecies equi using a triplex qPCR assay     

Katy Webb  Colin Barker  Tihana Harrison  Zoe Heather  Karen F. Steward  Carl Robinson  J. Richard Newton  Andrew S. Waller 《Veterinary journal (London, England : 1997)》2013,195(3):300-304

Genome sequencing data for Streptococcus equi subspecies equi and zooepidemicus were used to develop a novel diagnostic triplex quantitative PCR (qPCR) assay targeting two genes specific to S. equi (eqbE and SEQ2190) and a unique 100 base pair control DNA sequence (SZIC) inserted into the SZO07770 pseudogene of S. zooepidemicus strain H70. This triplex strangles qPCR assay can provide results within 2 h of sample receipt, has an overall sensitivity of 93.9% and specificity of 96.6% relative to the eqbE singlex assay and detects S. equi at levels below the threshold of the culture assay, even in the presence of contaminating bacteria.  相似文献   

Effects of a Cross‐linked Hyaluronic Acid Based Gel on the Healing of Open Wounds in Dogs     

Heather S. Hadley DVM  Bryden J. Stanley BVMS  MVetSc  Diplomate ACVS  Michele C. Fritz BS  LVT  Joe G. Hauptman DVM  MS  Diplomate ACVS  Barbara A. Steficek DVM  PhD  Diplomate ACVP 《Veterinary surgery : VS》2013,42(2):161-169

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Reference intervals for select hematologic and plasma biochemical analytes of wild Lake Sturgeon (Acipenser fulvescens) from the St. Lawrence River in New York     

Louis DiVincenti Jr.  Jeff Wyatt  Heather Priest  Dawn Dittman  Rodger Klindt  David Gordon  Andrew Preston  Thomas Smith  Colby Bowman 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2013,42(1):19-26

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Ultrasound-guided percutaneous antegrade hydropropulsion to relieve ureteral obstruction in a pet guinea pig (Cavia porcellus)     

David Eshar  Bridget Lee-Chow  Heather J. Chalmers 《The Canadian veterinary journal. La revue veterinaire canadienne》2013,54(12):1142-1145

Severe hydroureter and hydronephrosis secondary to ureteral obstruction by calculus were present in a guinea pig. A palliative ultrasound-guided percutaneous antegrade hydropropulsion was performed under general anesthesia to relieve the ureteral obstruction and the associated clinical signs. We describe the technique and the considerations for its potential application in similar cases.  相似文献   

Sociodemographic, health and lifestyle characteristics reported by discrete groups of adult dietary supplement users in Alberta, Canada: findings from The Tomorrow Project     

Robson PJ  Siou GL  Ullman R  Bryant HE 《Public health nutrition》2008,11(12):1238-1247

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Characterization of Mycobacterium avium subspecies paratuberculosis disseminated infection in dairy cattle and its association with antemortem test results   总被引：1，自引：0，他引：1  

Antognoli MC  Garry FB  Hirst HL  Lombard JE  Dennis MM  Gould DH  Salman MD 《Veterinary microbiology》2008,127(3-4):300-308

Mycobacterium avium subspecies paratuberculosis (MAP) disseminated infection in dairy cattle affects animal health and productivity and is also a potential public health concern. The study objectives were to characterize MAP disseminated infection in dairy cattle and to determine the role of antemortem tests in detecting cattle with disseminated infection. Forty culled dairy cows representing a variety of serum enzyme-linked immunosorbent assay (ELISA) results and body conditions were selected for the study. The physical condition of the cows was assessed via clinical examination prior to euthanasia and blood and feces were collected and tested by serum ELISA and fecal culture, respectively. Fifteen tissues were aseptically collected from each cow during necropsy and cultured for isolation of MAP. Disseminated infection was diagnosed when MAP was isolated in tissues other than the intestines or their associated lymph nodes (LNs) and was distinguished from infection found only in the gastrointestinal tissues and from absence of infection. Of the 40 cows in the study, 21 had MAP disseminated infection. Results showed that 57% (12/21) of cows with disseminated infection had average to heavy body condition and no diarrhea. Cows with disseminated infection had no to minimal gross pathologic evidence of infection in 37% (8/21) of cases. Only 76% (16/21) of cows with disseminated infection had positive historical ELISA results and only 62% (13/21) had a positive ELISA at slaughter. Thus, antemortem evidence of MAP infection was lacking in a high proportion of cows where MAP disseminated infection was confirmed.  相似文献   

Another perspective on veterinarians in public health     

Henderson H 《Journal of the American Veterinary Medical Association》2008,233(6):865-866

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