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In most previous studies of habitat selection, the use of a given habitat type is assumed to be directly proportional to its availability. However, the use and (or) the selection of a given habitat may be conditional on the availability of that habitat. We aim here to (i) identify the environmental variables involved in habitat selection, (ii) identify classes of individuals with similar patterns of habitat selection, and (iii) assess whether habitat use changes with changing availability of habitat types, within monthly home ranges of female western roe deer (Capreolus capreolus (L., 1758)). We found that some females adjust their habitat use according to the distribution of resources within habitats. Females with similar home ranges in terms of resource quantity and quality showed similar patterns of habitat selection. Differences in habitat use between 2 years with contrasting resource availability showed that temporal changes of environmental conditions influenced the pattern of habitat selection by female roe deer. Habitat selection also differed between periods of the life cycle likely because of contrasted energy requirements. This study shows that the relationship between habitat use by herbivores and habitat availability is nonproportional, and that the availability of resources influences use mostly at intermediate values. Dans la plupart des etudes anterieures sur la selection de l'habitat, l'utilisation d'un habitat donne est supposee etre directement proportionnelle a sa disponibilite. Cependant, l'utilisation et (ou) la selection d'un habitat donne peut etre conditionnelle a la disponibilite de cet habitat. Le but de cette etude est (i) d'identifier les variables environnementales impliqueees dans la selection de l'habitat, (ii) d'identifier les classes d'individus avec des patrons similaires de selection de l'habitat et (iii) de tester si l'utilisation d'habitat change avec une disponibilite; changeante des types d'habitat, dans les domaines vitaux mensuels des femelles chevreuils d'Europe (Capreolus capreolus (L., 1758)). Nous trouvons que certaines femelles ajustent leur utilisation d'habitat en fonction de la distribution des ressources dans les habitats. Les femelles avec des domaines vitaux similaires en termes de quantite et qualite de ressources montrent des patrons de selection de l'habitat similaires. Les differences dans l'utilisation d'habitat entre deux annees avec des disponibilitees de ressources contrasteees montrent que les variations dans le temps des conditions environnementales influencent le patron de selection de l'habitat chez les femelles de chevreuil. La selection de l'habitat differe aussi entre les peeriodes du cycle de vie a cause de besoins en energie bien diffeerencie;s. Cette etude montre que la relation entre l'utilisation et la disponibilite: des habitats est nonproportionnelle, et que la disponibilite des ressources influence l'utilisation, surtout aux valeurs intermediaries., Introduction Habitat selection is a hierarchical process involving behavioural decisions at different spatial scales (Hutto 1985), These decisions may result in disproportional use of some habitats and may lead to [...]

Abstract With the surge of GPS-technology, many studies uncovered space use of mobile animals and shed light on the underlying behavioral mechanisms of habitat selection. Habitat selection and variation in either occurrence or strength of functional responses (i.e. how selection changes with availability) have given new insight into such mechanisms within populations in different ecosystems. However, linking variation in habitat selection to site-specific conditions in different populations facing contrasting environmental conditions but the same habitat type has not yet been investigated. We aimed to fill this knowledge gap by comparing within-home range habitat selection across 61 female roe deer (Capreolus capreolus) during the most critical life history stage in three study areas showing the same habitat types but with different environmental conditions. Female roe deer markedly differed in habitat selection within their home range, both within and among populations. Females facing poor environmental conditions clearly displayed a functional response, whereas females facing rich environmental conditions did not show any functional response. These results demonstrate how the use of a given habitat relative to its availability strongly varies in response to environmental conditions. Our findings highlight that the same habitat composition can lead to very different habitat selection processes across contrasted environments.

Objective: We sought to assess the efficacy of preoperative autologous blood donation in reducing patient exposure to allogeneic blood products following elective cardiac surgery.Methods: We included 48 patients in a prospective study and randomly assigned them into the control or treatment group. We excluded patients with aortic stenosis, main trunk stenosis and unstable angina. Group A (n=23; coronary disease n=21 and valvular disease n=2) was the control group, and group B (n=25; coronary disease n=21, valvular disease n=4) received preoperative autologous blood donation. All patients had cardiopulmonary bypass surgery, and we processed mediastinal blood with a cell-saver device before reinfusion. All patients received aprotinin, and we reinfused blood shed from the mediastinum postoperatively.Results: No major peri- or postoperative complications occurred. We interrupted preoperative blood donation in 2 patients (8%) because of worsened angina pectoris. The mean time between the first blood donation and surgery was 22.5 (standard deviation [SD] 9.4, range 12-50) days. In group A, 9 patients (39.1%) were exposed to allogeneic blood products. In group B, 11 patients (47.8%) were exposed to blood products (p=0.73), and 4 (16%) were exposed to allogeneic blood products (p=0.036).Conclusion: Preoperative blood donation was completed in 92% of the targeted low-risk population. The procedure significantly reduced exposure to perioperative allogeneic blood products. [ABSTRACT FROM AUTHOR]

The purpose of this study was to evaluate the multiple dose pharmacokinetics and acute safety of piroxicam and cimetidine alone and in combination in cats. Seven healthy cats were included in this randomized-crossover study. The cats were assigned to groups designated to receive cimetidine alone (15 mg/kg, p.o., q12 h), piroxicam alone (0.3 mg/kg, p.o., q24 h), and piroxicam combined with cimetidine (both at aforementioned doses). The cats were dosed for 10 days followed by at least a 2-week washout period between trials. Serial blood samples were collected following the first and last doses and analyzed utilizing a high-performance liquid chromatography with mass spectrometry detection (LC/MS) assay. Pharmacokinetic parameters were determined using noncompartmental analysis. Endoscopic evaluation of the gastric mucosa was performed and serum urea nitrogen (SUN), creatinine, alkaline phosphatase (ALP), and alanine transaminase (ALT) activities were evaluated. There were not a clinically relevant difference between the pharmacokinetic parameters of piroxicam administered alone or in combination with cimetidine after either the first or last dose. Gastric ulcers were not observed in any cats although gastric erosions were. The SUN, creatinine, ALP, and ALT activities remained within reference ranges for all cats. It appears that once daily, short-term use of piroxicam alone and in combination with cimetidine in cats is relatively safe based on the parameters evaluated in this study. However, further studies are necessary to determine the long-term gastrointestinal safety of piroxicam. [ABSTRACT FROM AUTHOR]

Objective: To study the effect of mycophenolate mofetil (MMF), a new immunosuppressive drug that acts by inhibiting de novo pathways of purine synthesis, and rabbit antithymocyte globulin (RATG) on the lymphocyte subpopulation after heart transplantation.Design: A review of clinical and laboratory records.Setting: The Montreal Heart Institute.Patients: Thirty-one patients who underwent heart transplantation. In 9 patients, neoral cyclosporine, prednisone and azathioprine were administered (group 1). In 14 patients RATG was added during the first 3 postoperative days (group 2) and in 8 patients RATG and combination immunosuppression was given, but MMF was used instead of azathioprine (group 3). The demographic characteristics of donors and recipients were similar among the 3 groups.Main Outcome Measures: The proportion of CD2, CD4 and CD8 receptor-positive lymphocytes, expressed as a mean (and standard deviation) percentage of the total lymphocyte population, measured at 7, 15 and 30 days and 6 months after transplantation.Results: At 7 days after transplantation, CD2 lymphocytes averaged 55% (18%), 16% (15%) and 14% (11%) in groups 1, 2 and 3 respectively (p < 0.05), CD4 averaged 36% (11%), 9% (12%) and 7% (8%) in groups 1, 2 and 3 (p < 0.05), and CD8 averaged 14% (6%), 4% (3%) and 4% (3%) in groups 1, 2 and 3 (p < 0.05). At 15 days after transplantation CD2 averaged 69% (10%), 42% (16%) and 47% (20%) in groups 1, 2 and 3 respectively (p < 0.05), and CD8 averaged 16% (7%), 16% (6%) and 19% (7%) (p = NS). At 30 days after transplantation the percentages of CD2, CD4 and CD8 lymphocytes were similar among the groups. The freedom rate from acute rejection averaged 22% (14%), 9% (8%) and 50% (18%) (p < 0.05) in groups 1, 2 and 3 at 6 months after transplantation, and the freedom rate from infection averaged 56% (17%), 36% (13%) and 38% (17%) for the 3 groups at this time period (p = NS).Conclusions: A short course of RATG causes severe, transitory depletion of CD2, CD4 and CD8 lymphocyte subpopulations. MMF decreases the incidence of early acute rejection after heart transplantation without affecting the lymphocyte subpopulation when compared with azathioprine. [ABSTRACT FROM AUTHOR]