The costs of multiple patch use by birds

Birds living in fragmented habitat may occupy territories comprising more than one patch. This paper uses a theoretical model to investigate the costs (in terms of time and energy) of crossing gaps between patches for birds feeding young in the nest, using the great tit (Parus major) as an example. When the proportion of foraging trips involving gap-crossing was small (25%), gaps of about 300–550 m (depending on body mass and flight speed) could be crossed without exceeding likely maximum sustainable daily energy expenditure (DEE_max). However, a penalty of time lost in crossing gaps of about one hour was incurred. For more gap-crossing (due to larger brood size and/or a greater proportion of gap-crossing trips), distances that could be crossed decreased rapidly to about 50–100 m and time lost increased to more than six hours. Crossing gaps at maximum range speed, rather than at the slower minimum power speed, reduced flight times by 42% and slightly reduced overall daily energy expenditure because the higher flight costs per minute were more than off-set by the shorter flight times. Smaller body mass (17 g versus 19 g) was advantageous for gap-crossing, the distances which could be crossed without exceeding DEE_max being almost doubled for the smaller mass. The influence of changes in wing morphology, fat load and prey load size on the energetics of gap-crossing were also considered. Although the model was constructed for a woodland bird, problems of time and energy expenditure associated with gap-crossing will affect many species which exploit patchy resources, especially when the spacing of the patches increases, for example due to habitat loss and modification. In landscapes where semi-natural habitat is highly fragmented and most surviving patches are small (e.g., many farming landscapes) the costs of multiple patch use may represent another mechanism by which habitat fragmentation reduces the reproductive potential of the inhabitants of habitat patches which are of acceptable or even good quality, but are small.     

Clinical, microbiological, and molecular characterization of methicillin-resistant Staphylococcus aureus infections of cats

OBJECTIVE: To compare clinical information obtained from medical records of cats with methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-susceptible S aureus (MSSA) infections, evaluate antibiograms of MRSA and MSSA for multiple-drug resistance (MDR), and characterize the strain type and staphylococcal chromosome cassette (SCC)mec type of each MRSA. SAMPLE POPULATION: 70 S aureus isolates obtained from 46 cats. PROCEDURES: Clinical information obtained from medical records, including signalment, clinical signs, histologic examination of affected tissues, and outcomes, was compared between the 2 groups. Composite antibiograms of MRSA and MSSA were compared statistically. The MRSA strains were characterized by use of pulsed-field gel electrophoresis and SCCmec typing. RESULTS: No statistical differences in signalment or subjective differences in clinical signs or outcomes were detected between groups with MRSA or MSSA infection. Significant differences in antimicrobial resistance were detected, with MRSA having complete resistance to fluoroquinolone and macrolide antimicrobials, whereas MSSA maintained a high frequency of susceptibility. Seven pulsed-field patterns were observed in 15 MRSA strains; all but 1 were highly related. All MRSA isolates contained a type II SCCmec element. CONCLUSIONS AND CLINICAL RELEVANCE: Because MDR cannot be predicted in staphylococcal infections in cats on the basis of clinical signalment, culture and susceptibility testing are recommended whenever initial empirical treatment is unsuccessful. Molecular characterization of MRSA strains suggests that there has been reverse-zoonotic transmission from humans. IMPACT FOR HUMAN MEDICINE: The SCCmec type II element is typically associated with nosocomial MRSA infections of people. Cats may serve as reservoirs for MRSA infections in humans.     

Efficacy and safety of firocoxib in the management of canine osteoarthritis under field conditions

A total of 249 client-owned dogs with osteoarthritis were treated with firocoxib (5 mg/kg/day) or a positive control, etodolac (10-15 mg/kg/day), for 30 days. Veterinary examinations were performed on approximately days 0 (visit 1), 14 (visit 2), and 29 (visit 3). Based on defined noninferiority criteria, firocoxib and etodolac were comparable. Based on the magnitude of the change from baseline, improvement with firocoxib was significantly greater than with etodolac for lameness at a trot (visits 2 and 3) and for lameness at a walk, pain on manipulation, and range of motion (visit 3) (P < .05). In weekly owner evaluations, firocoxib provided significantly greater improvement than etodolac (P < .05) at each scoring.     

Economic development and biotechnology: Public policy response to the farm crisis in Iowa

In periods of social crisis, policymakers become particularly vulnerable to interest groups mobilizing to compete for scarce funds. At this point, legislators are no longer able to address the specific needs of their primary constituency directly, but rather are forced to do so in pretext only. New, unfamiliar technologies provide ample ammunition for astute interest groups to take advantage of times of economic turmoil and maneuver for policy support through dramatic campaigns of “salesmanship.” By publicizing a crisis situation, dramatizing it effectively, and advertising an innovation as the solution to the crisis, legislators may be effectively persuaded to give priority to interest group pressures above and beyond those of the local constituency. Iowa's attempts to address the farm crisis through economic development strategies relying on biotechnology is examined in this paper. The results of extensive surveys of Iowa's legislators and farmers are examined and the consequences for Iowa's policy process of using biotechnology under the auspices of economic development are discussed.     

Leaf orientation,light interception and stomatal conductance of Eucalyptus globulus ssp. globulus leaves

Juvenile and adult leaves of the heteroblastic species Eucalyptus globulus Labill. ssp. globulus did not show active diurnal orientation toward or away from incident radiation. Juvenile leaves of a late-maturing sapling of a Tasmanian provenance were evenly distributed in all azimuth sectors. In contrast, an early-maturing sapling of the same age from Wilsons Promontory, Victoria had a predominance of adult leaf blades facing east and west. Mid-vein and blade angles of juvenile and adult leaves were non-random with an overall vertical declination of the leaves. Both leaf types intercepted a greater irradiance during the morning than at midday. Sub-horizontal juvenile leaves intercepted 22% more irradiance than vertical adult leaves during the middle of the day. The amphistomatal and isobilateral adult leaves intercepted sunlight equally on both leaf surfaces. Stomatal conductance was variable during the period of measurement but was similar for the Tasmanian juvenile (0.4 to 0.9 cm s(-1)) leaves and Wilsons Promontory adult (0.5 to 1.2 cm s(-1)) leaves. Greater light interception by the sub-horizontal juvenile leaves would confer a growth advantage to saplings and regenerating canopies. Reduced light interception and leaf temperature of vertical adult E. globulus leaves would assist in water conservation, particularly at high solar angles.