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541.
Newly proposed federal regulations will mandate that singly caged non-human primates be kept in cages larger than the current minimum standard, or be given 4 hours in an exercise cage per week. In order to evaluate the effectiveness of increasing cage size in improving well-being, the behavioral and heart rate responses of 10 female rhesus monkeys (Macaca mulatta) to three different cage sizes were measured. With the exception of vocalizations, no significant differences in behavior were obtained. Grunts increased in the largest cage, following the birth of an infant in a cage within view of the test cages. No differences with respect to cage size were found in heart rate or activity level, although there were significant variations at different times of day. We conclude that modest increases in cage size are less likely to enrich the environment of singly caged laboratory primates than are changes in social opportunities or increases in environmental complexity.  相似文献   
542.
543.
  1. It is often suggested to release oaks (Quercus robur) from competition, to ensure their survival and boost their conservational value. However, few studies have explored how long-lasting this effect is and how it affects saproxylic beetles.
  2. Ten years after cutting, we investigated effects of different release cutting levels (high, medium, and no release) around 140-year-old retained oaks in a commercial forest with Norway spruce (Picea abies).
  3. We evaluated oak vitality using crown and dead wood measurements. Saproxylic beetles were caught in window traps, identified to species level, and grouped according to their association with oak and/or Norway spruce.
  4. Released oaks had more light, higher temperatures, greater crown growth, and less dead wood in the crown compared to the no-release control.
  5. After 10 years we still found a higher abundance of oak-associated beetles and higher overall species richness of saproxylic beetles in the released oaks. Beetle species composition significantly differed between released oaks and control.
  6. We suggest avoiding planting trees beneath retained oaks when regenerating conifer forests and to proceed with conservation management during subsequent thinning by removing regeneration under the oak crowns. We emphasize the benefits of monitoring the retained oaks to maintain tree vitality, habitat quality, and insolation.
  相似文献   
544.
Thirty-four cases of acute bacillary dysentery occurred within 90 days among macaques housed at the California Regional Primate Research Center. Cases were identified by depression, diarrhea with blood and leukocytic exudate, and/or leukocytosis with a left shift. Antimicrobial susceptibility testing of enteric isolates and plasmid profile analyses established an etiologic diagnosis of multiple antibiotic resistant Shigella flexneri IV infection. When standard therapies were invalidated by high frequencies of resistance among the isolates, therapy with enrofloxacin, a fluoroquinolone antimicrobial, was initiated to interrupt the epidemic. Serum concentrations of enrofloxacin and its primary metabolite ciprofloxacin were measured in selected cases. A serum concentration-time data analysis was performed to evaluate the oral enrofloxacin dose and dosing interval for nonfasted macaques. Once daily administration of 5 mg/kg enrofloxacin by gastric intubation produced 24-hour serum concentrations above the MICs for the Shigella isolates from this outbreak.  相似文献   
545.
Summary The N2-fixing biota of Macquarie Island are dominated by cyanobacteria growing epiphytically or symbolically with plants or lichens. Highest rates of C2H2-reducing activity were found in the leafy lichen Peltigera sp. colonizing herbfields and short grasslands and in the coastal angiosperm Colobanthus muscoides. Significant rates of C2H2 reduction were also found to be associated with the liverwort Jamesoniella colorata, commonly occurring in coastal and plateau mires, in a mossbed of Dicranella cardotii colonizing a land-slip face on the grassland slopes at 100 m altitude and within polsters of the mosses Ditrichum strictum and Andreaea sp. found in exposed localities on the plateau at 200–300 m altitude. It was concluded that the common feature of plants supporting active N2 fixation in dry habitats was the dense packing of stems and leaves, enabling water translocation to the cyanobacterial zone by wick action. Epiphytic cyanobacterial C2H2 reduction in wet habitats was widespread and not restricted to any particular plant species. Notable N2-fixing lichens of the plateau were Pseudocyphellaria delisea and Stereocaulon sp., although both were also occasionally found in coastal herbfields. No significant N2-fixing activity was associated with any of the dominant grasses tested. Heterotrophic N2 fixation was also found to be insignificant in the various habitats tested, however N2-fixing Bacillus (B. macerans or B. polymyxa) were universally present in coastal, grassland slope, or plateau samples, including moss polster samples. A N2fixing Clostridium sp. was isolated in only one instance, from soil in the vicinity of a seal wallow on the coast.  相似文献   
546.
547.
In terrestrial snails, thermal selection acts on shell coloration. However, the biological relevance of small differences in the intensity of shell pigmentation and the associated thermodynamic, physiological, and evolutionary consequences for snail diversity within the course of environmental warming are still insufficiently understood. To relate temperature‐driven internal heating, protein and membrane integrity impairment, escape behavior, place of residence selection, water loss, and mortality, we used experimentally warmed open‐top chambers and field observations with a total of >11,000 naturally or experimentally colored individuals of the highly polymorphic species Theba pisana (O.F. MÜller, 1774). We show that solar radiation in their natural Mediterranean habitat in Southern France poses intensifying thermal stress on increasingly pigmented snails that cannot be compensated for by behavioral responses. Individuals of all morphs acted neither jointly nor actively competed in climbing behavior, but acted similarly regardless of neighbor pigmentation intensity. Consequently, dark morphs progressively suffered from high internal temperatures, oxidative stress, and a breakdown of the chaperone system. Concomitant with increasing water loss, mortality increased with more intense pigmentation under simulated global warming conditions. In parallel with an increase in mean ambient temperature of 1.34°C over the past 30 years, the mortality rate of pigmented individuals in the field is, currently, about 50% higher than that of white morphs. A further increase of 1.12°C, as experimentally simulated in our study, would elevate this rate by another 26%. For 34 T. pisana populations from locations that are up to 2.7°C warmer than our experimental site, we show that both the frequency of pigmented morphs and overall pigmentation intensity decrease with an increase in average summer temperatures. We therefore predict a continuing strong decline in the frequency of pigmented morphs and a decrease in overall pigmentation intensity with ongoing global change in areas with strong solar radiation.  相似文献   
548.
An adult male Callicebus moloch was presented for acute congestive heart failure. Therapy was unsuccessful and necropsy showed severe systemic atherosclerosis. Analysis of serum revealed hypercholesterolemia with specific elevation of the betalipoprotein fraction.  相似文献   
549.
The farming landscape of eastern Canada is dotted with three main types of hedgerows: (1) natural woody, (2) planted woody and (3) herbaceous. The objective of this study was to compare the value of these habitats as a repository of plant biodiversity in agricultural areas of southern Quebec. The overall plant diversity was higher in natural hedgerows and they contained more plant species of conservation values than other hedgerow types. Plant species richness per quadrat was, however, higher in planted woody hedgerows, and together with the species composition, lead to the conclusion that planted hedgerows in their entirety consisted of an ecotone type of vegetation such as is found in field edges which usually support high plant diversity and productivity but where transient plant species predominate. Consequently, this study indicated that natural hedgerows fare better than planted hedgerows in terms of diversity of plants of conservation interest. In spite of that, planted woody hedgerows contained plant (and bird) species of some interest and should be favoured over more desolate herbaceous hedgerows. In areas where hedgerows were removed and are not re-establishing naturally, a mixture of deciduous trees and conifers should be encouraged in further windbreak planting programs so as to conciliate both the conservation and agronomic objectives. Furthermore, management practices should optimise the growth of establishing plants of conservation values.  相似文献   
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