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Shorter Distances (shorter + distance)
Selected AbstractsAvailability of Safety Net Providers and Access to Care of Uninsured PersonsHEALTH SERVICES RESEARCH, Issue 5 2004Jack Hadley Objective. To understand how proximity to safety net clinics and hospitals affects a variety of measures of access to care and service use by uninsured persons. Data Sources. The 1998,1999 Community Tracking Study household survey, administered primarily by telephone survey to households in 60 randomly selected communities, linked to data on community health centers, other free clinics, and safety net hospitals. Study Design. Instrumental variable estimation of multivariate regression models of several measures of access to care (having a usual source of care, unmet or delayed medical care needs, ambulatory service use, and overnight hospital stays) against endogenous measures of distances to the nearest community health center and safety net hospital, controlling for characteristics of uninsured persons and other area characteristics that are related to access to care. The models are estimated with data from a nationally representative sample of uninsured people. Principal Findings. Shorter distances to the nearest safety net providers increase access to care for uninsured persons. Failure to account for the endogeneity of distance to safety net providers on access to care generally leads to finding little or no safety net effects on access. Conclusions. Closer proximity to the safety net increases access to care for uninsured persons. However, the improvements in access to care are relatively small compared with similar measures of access to care for insured persons. Modest expansion of the safety net is unlikely to provide a full substitute for insurance coverage expansions. [source] Risk Assessment and Withdrawal Behavior by Two Species of Aposematic Poison Frogs, Dendrobates auratus and Oophaga pumilio, on Forest TrailsETHOLOGY, Issue 4 2009William E. Cooper Jr Many chemically defended prey advertize toxicity to predators by aposematic coloration. When aposematic prey are approached, they often move slowly or not at all, allowing predators to evaluate their unprofitability. Poison frogs (Dendrobatidae) are toxic, aposematically colored, forage openly and diurnally, and are much easier to capture than many palatable frogs. Although protected against diverse predators, they are sometimes attacked and are subjected to injury by large animals without predatory intent. We predicted that they have limited escape behavior, but retain ability to assess and respond to risk. When we approached Dendrobates auratus and Oophaga pumilio on forest trails, both species hopped by the shortest route to the nearer forest edge and stopped there. When approached, D. auratus moved after shorter latency at an angle closer to perpendicular to the forest edge, were more likely to leave the trail, and left the trail sooner with fewer changes in direction after moving a shorter distance than when not approached. In agreement with predictions of optimal escape theory based on risk, flight initiation distance by D. auratus was greater when approached directly than indirectly and rapidly than slowly, and was greater when frogs were in the open than partially concealed. Frogs neither attempted rapid escape nor entered refuges. Both species hopped leisurely and remained visible after stopping. They exhibit the diminished escape behavior of aposematic prey, yet retain the capacity to assess risk and adjust behavior accordingly. Their behavior demonstrates continued need for escape behavior by highly toxic aposematic prey. [source] Alarm Calls Affect Foraging Behavior in Eastern Chipmunks (Tamias striatus, Rodentia: Sciuridae)ETHOLOGY, Issue 12 2000Jessica K. Baack We used playback experiments to test whether alarm calls affected the foraging behavior of eastern chipmunks (Tamias striatus). We subjected chipmunks, foraging at artificial feeding stations, to three playback treatments (silent, control noise, and alarm call) and examined changes in vigilant and foraging behavior. Chipmunks responded to alarm calls with a greater degree and duration of vigilant behavior, such as look-ups and alert postures. Chipmunks also ran a shorter distance to cover and took longer to re-emerge from the burrow after hearing an alarm call. Alarm calls caused individuals to spend more time exposed at the feeding stations; however, individuals also took significantly fewer seeds after hearing an alarm call. This was not due to a difference in the time spent handling food, but rather to a slower rate of loading. Chipmunks appear to sacrifice energy gain by increasing vigilance after hearing an alarm call. This study suggests that to avoid the costs of unnecessary escape behavior, individuals directly assess their own risk rather than relying only on indirect cues such as alarm calls. [source] Spatial patterns and environmental factors affecting the presence of Melampsorella caryophyllacearum infections in an Abies alba forest in NE SpainFOREST PATHOLOGY, Issue 3 2006A. Solla Summary The presence of trunk swellings caused by the rust fungus Melampsorella caryophyllacearum was systematically surveyed in an Abies alba forest (Irati, NE Spain), using 1237 circular plots (diameter = 18 m). The relationship between fungal presence and several abiotic (aspect, elevation, distance to the nearest river and slope) and biotic factors (basal area of A. alba and/or Fagus sylvatica, shrub, fern and herb cover) was assessed through correlation and ordination analyses. Additionally, the spatial pattern of the presence of diseased trees was described using Ripley's K function. Southern-aspect plots had a significantly lower presence of diseased trees than plots-oriented north, east and west. Plots with diseased trees were located at a significantly lower elevation, and at a shorter distance to the river than plots without infections. Plots with diseased trees had almost twice the average A. alba basal area, and less average F. sylvatica basal area than plots without diseased trees. However, similar mean values of slope and shrub, fern and herb cover were found in both types of plots. The disease showed spatial aggregation in patches with a mean radius of ca. 900 m. The implications of the results for disease management are discussed. Résumé La présence de renflements sur les troncs causés par l'agent de la rouille, Melampsorella caryophyllacearum, a étéétudiée de façon systématique dans une forêt d'Abies alba (Irati, NE Espagne), en utilizant 1237 placettes circulaires (diamètre de 18 m). Les relations entre la présence du champignon et divers facteurs abiotiques (orientation, altitude, distance à la rivière la plus proche, pente) et biotiques ( surface terrière de A. alba et/ou Fagus sylvatica, abondance de la couverture herbacée et abondance d'arbustes et fougères) ont étéétudiées par analyses de corrélation et d'ordination. D'autre part, la structure spatiale de la présence d'arbres infectés a été décrite en utilizant la fonction K de Ripley. Les placettes exposées au sud présentent moins fréquemment des arbres malades que celles exposées au nord, à l'est ou à l'ouest. Les placettes avec des arbres malades sont situées à une altitude significativement plus faible et à une distance plus faible d'une rivière que les placettes sans infections, et elles présentent une surface terrière 2 fois plus forte en moyenne pour A. alba, et plus faible pour F. sylvatica, que les placettes non-infectées. Toutefois, des valeurs moyennes équivalentes pour la pente, la couverture herbacée et l'abondance d'arbustes et fougères, sont observées pour les deux types de placettes. La maladie montre une agrégation spatiale en foyers d'un rayon moyen de 900 m. Les résultats sont discutés dans une perspective de gestion de la maladie. Zusammenfassung Das Vorkommen von durch den Rostpilz Melampsorella caryophyllacearum verursachten Stammdeformationen wurde in einem Abies alba - Wald (Irati, NO-Spanien) auf 1237 kreisförmigen Probeflächen (Durchmesser 18 m) systematisch erfasst. Die Beziehung zwischen dem Pilzvorkommen und mehreren abiotischen (Exposition, Meereshöhe, Distanz zum nächsten Fluss, Hangneigung) und biotischen Faktoren (Deckungsgrad von A. alba und/oder Fagus sylvatica, Strauch-, Farn- und Krautschicht) wurden durch Korrelations- und Ordinations-Analysen überprüft. Zudem wurden räumliche Muster der befallenen Bäume mit Hilfe von Ripley's K-Funktion beschrieben. In südexponierten Probeflächen kamen signifikant weniger erkrankte Bäume vor als in nach Norden, Osten und Westen orientierten Standorten. Flächen mit Befall lagen in signifikant geringerer Meereshöhe und kürzerer Distanz zum nächsten Fluss als solche ohne Befall. Zudem hatten sie beinahe die doppelte Basalfläche mit A. alba und eine durchschnittliche geringere Basalfläche mit F. sylvatica. Die durchschnittlichen Werte für die Strauch-, Farn- und Krautschicht sowie die Hangneigung unterschieden sich jedoch nicht in den Flächen mit und ohne Befall. Erkrankte Bäume waren räumlich aggregiert mit einem mittleren Radius von ca. 900 m. Die Bedeutung dieser Befunde für das Krankheitsmanagement wird diskutiert. [source] Comparative analysis of food-finding behavior of an herbivorous and a carnivorous land snailINVERTEBRATE BIOLOGY, Issue 3 2001Alyssa Shearer Abstract. Although the olfactory capabilities of land snail tentacles have been tested by lesion studies and unilateral exposure of tentacles to specific odors, studies of a carnivorous species suggest that the anatomical similarities of herbivorous and carnivorous land snails may belie a fundamental difference in the way these structures are used to find food. Therefore, we challenged the herbivore, Anguispira alternata, and the carnivore, Haplotrema concavum, to find a stationary food source (carrot and caged young prey snail, respectively) under identical still air conditions. The herbivore traveled a significantly shorter distance to the food, even negotiating a barrier placed halfway between the snail and its food. The carnivore, on the other hand, followed a circuitous, apparently random, path to the food. Subsequent tests revealed that H. concavum readily follows prey slime trails while A. alternata seldom follows conspecific slime trails when a distant food source is available. These results are consistent with what might be expected as adaptations to the usually mobile nature of carnivore prey and the stationary nature of herbivore food plants. The ability of A. alternata to exhibit typical detour behavior is noted. [source] Accurate long-range distance measurements in a doubly spin-labeled protein by a four-pulse, double electron,electron resonance methodMAGNETIC RESONANCE IN CHEMISTRY, Issue 12 2008Michela G. Finiguerra Abstract Distance determination in disordered systems by a four-pulse double electron,electron resonance method (DEER or PELDOR) is becoming increasingly popular because long distances (several nanometers) and their distributions can be measured. From the distance distributions eventual heterogeneities and dynamics can be deduced. To make full use of the method, typical distance distributions for structurally well-defined systems are needed. Here, the structurally well-characterized protein azurin is investigated by attaching two (1-oxyl-2,2,5,5-tetramethylpyrroline-3-methyl) methanethiosulfonate spin labels (MTSL) by site-directed mutagenesis. Mutations at the surface sites of the protein Q12, K27, and N42 are combined in the double mutants Q12C/K27C and K27C/N42C. A distance of 4.3 nm is found for Q12C/K27C and 4.6 nm for K27C/N42C. For Q12C/K27C the width of the distribution (0.24 nm) is smaller than for the K27C/N42C mutant (0.36 nm). The shapes of the distributions are close to Gaussian. These distance distributions agree well with those derived from a model to determine the maximally accessible conformational space of the spin-label linker. Additionally, the expected distribution for the shorter distance variant Q12C/N42C was modeled. The width is larger than the calculated one for Q12C/K27C by 21%, revealing the effect of the different orientation and shorter distance. The widths and the shapes of the distributions are suited as a reference for two unperturbed MTSL labels at structurally well-defined sites. Copyright © 2008 John Wiley & Sons, Ltd. [source] An Experimental Investigation of Landscape Resistance of Forest versus Old-Field Habitats to Emigrating Juvenile AmphibiansCONSERVATION BIOLOGY, Issue 5 2002Betsie B. Rothermel Larval amphibians,spotted salamander (Ambystoma maculatum), small-mouthed salamander (A. texanum), and American toad ( Bufo americanus ),were added to artificial pools in four dispersal arrays on forest edges. Each array consisted of a pool surrounded by a circular drift fence with pitfall traps and two 2.5 × 50 m enclosures (runs) extending into forest and old-field habitat. Juveniles captured at the circular fences were individually marked and released into either field or forest runs. We determined initial distance, initial rate, total distance, and net distance moved by juveniles in the field versus forest from recaptures in the runs. We also conducted 24-hour dehydration trials to compare the rates of evaporative water loss by spotted and small-mouthed salamanders in field and forest. Initial orientation of spotted salamanders and toads was significantly biased toward forest. Orientation of small-mouthed salamanders did not differ significantly from random expectations. The avoidance of open-canopy habitat by juvenile American toads in particular indicates that predictions of dispersal behavior based on adult habitat use may be misleading. Spotted salamanders moved almost four times farther and toads more than three times farther into the forest than into the field, and recapture rates of both species were much lower in the field. We attribute the lower recapture rates and shorter distances moved in the field to higher mortality due to desiccation or an abundance of predators. Juvenile spotted and small-mouthed salamanders experienced greater evaporative water loss in the field. Our data on movement behavior and dehydration rates suggest that old-field habitats offer greater landscape resistance to dispersing juveniles of some species. Thus, forest fragmentation is likely to reduce dispersal rates between local populations of these three species, with potentially negative consequences for population persistence in altered landscapes. Resumen: Utilizamos un enfoque experimental para investigar los efectos de la composición del paisaje sobre el éxito inicial de dispersión de anfibios juveniles. Colcamos larvas de anfibios (salamandras manchadas [Ambystoma maculatum] y A. texanum y sapo americano [Bufo americanus] ) en estanques artificiales en cuatro secuencias de dispersión en bordes de bosque. Cada secuencia consistió de un estanque rodeado por un cerco circular con trampas de fosa y dos encierros (corridas) de 2.5 × 50 m que se extendían hacia el hábitat de bosque y de campo viejo. Los juveniles capturados en los cercos circulares fueron marcados individualmente y liberados en las corridas de bosque o de campo. A partir de recapturas en las corridas, determinamos la distancia inicial, la tasa inicial, las distancia total y la distancia neta recorrida por juveniles en el campo versus el bosque. También realizamos pruebas de deshidratación de 24 horas para comparar las tasas de pérdida de agua por evaporación en salamandras en el campo y el bosque. La orientación inicial de Ambystoma maculatum y Bufo americanus estuvo significativamente sesgada hacia el bosque. La orientación inicial de A. texanum no fue significativamente diferente de las expectativas aleatorias. La evasión del hábitat abierto en particular por juveniles de sapo americano indica que las predicciones del comportamiento de dispersión basadas en el uso del hábitat por adultos pueden llevar a conclusiones erróneas. Las salamandras manchadas se movieron cuatro veces mas lejos y los sapos más de tres veces más lejos dentro del bosque que dentro del campo, y las tasas de recaptura de ambas especies fueron mucho menores en el campo. Atribuimos las bajas tasas de recaptura y las distancias menores a la mayor mortalidad debido a la desecación o a la abundancia de depredadores. Los juveniles de las dos especies de salamandras experimentaron mayor pérdida de agua por evaporación en los campos. Nuestros datos del comportamiento de movimiento y las tasas de deshidratación sugieren que los hábitats de campo viejo ofrecen mayor resistencia de paisaje para los juveniles dispersantes de algunas especies. Por tanto, es probable que la fragmentación de bosques reduce las tasas de dispersión entre poblaciones locales de estas tres especies, con consecuencias potencialmente negativas para la persistencia de la población en paisajes alterados. [source] Host tree architecture mediates the effect of predators on herbivore survivalECOLOGICAL ENTOMOLOGY, Issue 3 2006JANNE RIIHIMÄKI Abstract 1.,Vegetation structural complexity is an important factor influencing ecological interactions between different trophic levels. In order to investigate relationships between the architecture of trees, the presence of arthropod predators, and survival and parasitism of the autumnal moth Epirrita autumnata Borkhausen, two sets of experiments were conducted. 2.,In one experiment, the architectural complexity of mountain birch was manipulated to separate the effects of plant structure and age. In the other experiment the trees were left intact, but chosen to represent varying degrees of natural complexity. Young autumnal moth larvae were placed on the trees and their survival was monitored during the larval period. 3.,The larvae survived longer in more complex trees if predation by ants was prevented with a glue ring, whereas in control trees smaller canopy size improved survival times in one experiment. The density of ants observed in the trees was not affected by canopy size but spider density was higher on smaller trees. The effect of canopy structure on larval parasitism was weak; larger canopy size decreased parasitism only in one year. Until the fourth instar the larvae travelled shorter distances in trees with reduced branchiness than in trees with reduced foliage or control treatments. Canopy structure manipulation by pruning did not alter the quality of leaves as food for larvae. 4.,The effect of canopy structure on herbivore survival may depend on natural enemy abundance and foraging strategy. In complex canopies herbivores are probably better able to escape predation by ambushing spiders but not by actively searching ants. [source] Heteromyopia and the spatial coexistence of similar competitorsECOLOGY LETTERS, Issue 1 2003David J. Murrell Abstract Most spatial models of competing species assume symmetries in the spatial scales of dispersal and interactions. This makes analysis tractable, and has led to the conclusion that segregation of species in space does not promote coexistence. However, these symmetries leave parts of the parameter space uninvestigated. Using a moment-approximation method, we present a spatial version of the Lotka,Volterra competition equations to investigate effects of removing symmetries in the distances over which individuals disperse and interact. Some spatial segregation of the species always comes about due to competition, and such segregation does not necessarily lead to coexistence. But, if interspecific competition occurs over shorter distances than intraspecific competition (heteromyopia), spatial segregation becomes strong enough to promote coexistence. Such coexistence is most likely when the species have similar dynamics, in contrast to the competition,colonization trade-off that requires large competitive differences between species. [source] Thyroid hormone responses to endurance exerciseEQUINE VETERINARY JOURNAL, Issue S36 2006E. A. GRAVES Summary Reasons for performing study: Limited information exists about changes in circulating thyroid hormone concentrations during prolonged endurance exercise in horses. Objective: To examine the effects of prolonged exercise on serum iodothyronine concentrations in horses performing endurance exercise of varying distances. Methods: Serum concentrations of iodothyronines were measured in horses before and after completion of 40, 56, 80 and 160 km endurance rides (Study 1); daily during a 5 day, 424 km endurance ride (Study 2); and before and for 72 h after completion of a treadmill exercise test simulating a 60 km endurance ride (Study 3). Results: In Study 1, 40 and 56 km of endurance exercise had little effect on serum iodothyronine concentrations with the exception of a 10% decrease (P<0.05) in free thyroxine (FT4) concentration after the 56 km ride. In contrast, total thyroxine (T4), total triiodothyronine (T3), FT4 and free triiodothyronine (FT3) concentrations all decreased (P<0.05) after successful completion of 80 and 160 km rides, with decreases ranging from 13,31% and 47,54% for distances of 80 and 160 km, respectively. Further, pre-ride T4 concentration was lower (P<0.05) and FT3 concentration was higher (P<0.05) in horses competing 160 km as compared to horses competing over shorter distances. In Study 2, serum concentrations of T4, T3 and reverse triiodothyronine (rT3) progressively decreased (P<0.05) over the course of the multi-day ride. In Study 3, the greatest decrease (P<0.05) in all iodothyronines was observed at 12 h of recovery, ranging from 25% for FT4 to 53% for FT3, but all thyroid hormone concentrations had returned to the pre-exercise values by 24 h of recovery. Conclusion: Endurance exercise results in transient decreases in serum iodothyronine concentrations. Potential relevance: These data are important to consider when thyroid gland function is assessed by measurement of serum iodothyronine concentrations in endurance horses. [source] Detection and Avoidance of Predators in White-Tailed Deer (Odocoileus virginianus) and Mule Deer (O. hemionus)ETHOLOGY, Issue 2 2001Susan Lingle In this paper, we investigate the relationship between early detection of predators and predator avoidance in white-tailed deer (Odocoileus virginianus) and mule deer (O. hemionus), two closely related species that differ in their habitat preferences and in their anti-predator behavior. We used observations of coyotes (Canis latrans) hunting deer to test whether the distance at which white-tails and mule deer alerted to coyotes was related to their vulnerability to predation. Coyote encounters with both species were more likely to escalate when deer alerted at shorter distances. However, coyote encounters with mule deer progressed further than encounters with white-tails that alerted at the same distance, and this was not due to species differences in group size or habitat. We then conducted an experiment in which a person approached groups of deer to compare the detection abilities and the form of alert response for white-tails and mule deer, and for age groups within each species. Mule deer alerted to the approacher at longer distances than white-tails, even after controlling for variables that were potentially confounding. Adult females of both species alerted sooner than conspecific juveniles. Mule deer almost always looked directly at the approacher as their initial response, whereas white-tails were more likely to flee or to look in another direction with no indication that they pinpointed the approacher during the trial. Mule deer may have evolved the ability to detect predators earlier than white-tails as an adaptation to their more open habitats, or because they need more time to coordinate subsequent anti-predator defenses. [source] Estimating the Variability of Active-Layer Thaw Depth in Two Physiographic Regions of Northern AlaskaGEOGRAPHICAL ANALYSIS, Issue 2 2001Claire E. Gomersall The active layer is the zone above permafrost that experiences seasonal freeze and thaw. Active-layer thickness varies annually in response to air and surface temperature, and generally decreases poleward. Substantially less is known about thaw variability across small lateral distances in response to topography, parent material, vegetation, and subsurface hydrology. A graduated steel rod was used to measure the 1998 end-of-season thaw depth across several transects. A balanced hierarchical sampling design was used to estimate the contribution to total variance in active-layer depth at separating distances of 1, 3, 9, 27, and 100 meters. A second sampling scheme was used to examine variation at shorter distances of 0.3 and 0.1 meter. This seven-stage sample design was applied to two sites in the Arctic Foothills physiographic province, and four sites on the Arctic Coastal Plain province in northern Alaska. The spatial variability for each site was determined using ANOVA and variogram methods to compare intersite and inter-province variation. Spatial variation in thaw depth was different in the Foothills and Coastal Plain sites. A greater percentage of the total variance occurs at short lag distances (0,3 meters) at the Foothills sites, presumably reflecting the influence of frost boils and tussock vegetation on ground heat flow. In contrast, thaw variation at the Coastal Plain sites occurs at distances exceeding 10 meters, and is attributed to the influence of well-developed networks of ice-wedge polygons and the presence of drained thaw-lake basins. This information was used to determine an ongoing sampling scheme for each site and to assess the suitability of each method of analysis. [source] Self-motion and the origin of differential spatial scaling along the septo-temporal axis of the hippocampusHIPPOCAMPUS, Issue 7 2005Andrew P. Maurer Abstract Spatial scaling of place specific activity in the hippocampus varies systematically from the septal pole (high resolution) to the temporal pole (low resolution). Place fields get progressively larger, and the probability of observing a field in a given environment gets progressively smaller. It was previously found that decoupling movement in space from ambulation, by having the animal actively ride on a mobile platform, results in marked enlargement of the spatial scale factor in the dorsal hippocampus and a reduction in the increase in theta rhythm power with running speed, suggesting that a self-motion signal determines the spatial scale at which the hippocampal population vector updates. These results led to the hypothesis that the gain of the self-motion signal may vary systematically along the septo-temporal axis of the hippocampus. To test this hypothesis, EEG theta rhythm and ensembles of CA1 pyramidal cells and interneurons were recorded from the extreme dorsal and middle portions of the hippocampus. Pyramidal cell population vectors representing successive locations became decorrelated over substantially shorter distances in the dorsal than in the middle hippocampus. Dorsal pyramidal cells had smaller place fields, higher mean and peak firing rates, and higher intrinsic oscillation frequencies during track running than that of middle pyramidal cells. Both dorsal pyramidal cells and interneurons had more elevated mean rates during running, compared with rest, than that of the corresponding cell classes in the middle hippocampus, and both cell classes increased their rates more as a function of speed in the dorsal hippocampus. The amplitude, but not the frequency of fissure recorded theta rhythm, increased more as a function of running speed in the dorsal than in the middle hippocampus. We conclude that variation in the neuronal response to movement speed is the likely basis for the systematic variation in spatial scaling along the septo-temporal axis of the hippocampus. © 2005 Wiley-Liss, Inc. [source] Investigation of critical inter-related factors affecting the efficacy of pulsed light for inactivating clinically relevant bacterial pathogensJOURNAL OF APPLIED MICROBIOLOGY, Issue 5 2010H.P. Farrell Abstract Aims:, To investigate critical electrical and biological factors governing the efficacy of pulsed light (PL) for the in vitro inactivation of bacteria isolated from the clinical environment. Development of this alternative PL decontamination approach is timely, as the incidence of health care,related infections remains unacceptably high. Methods and Results:, Predetermined cell numbers of clinically relevant Gram-positive and Gram-negative bacteria were inoculated separately on agar plates and were flashed with ,60 pulses of broad-spectrum light under varying operating conditions, and their inactivation measured. Significant differences in inactivation largely occurred depending on the level of the applied lamp discharge energy (range 3·2,20 J per pulse), the amount of pulsing applied (range 0,60 pulses) and the distance between light source and treatment surface (range 8,20 cm) used. Greater decontamination levels were achieved using a combination of higher lamp discharge energies, increased number of pulses and shorter distances between treatment surface and the xenon light source. Levels of microbial sensitivity also varied depending on the population type, size and age of cultures treated. Production of pigment pyocynanin and alginate slime in mucoid strains of Pseudomonas aeruginosa afforded some protection against lethal action of PL; however, this was evident only by using a combination of reduced amount of pulsing at the lower lamp discharge energies tested. A clear pattern was observed where Gram-positive bacterial pathogens were more resistant to cidal effects of PL compared to Gram negatives. While negligible photoreactivation of PL-treated bacterial strains occurred after full pulsing regimes at the different lamp discharge energies tested, some repair was evident when using a combination of reduced pulsing at the lower lamp discharge energies. Strains harbouring genes for multiple resistances to antibiotics were not significantly more resistant to PL treatments. Slight temperature rises (,4·2°C) were measured on agar surfaces after extended pulsing at higher lamp discharge energies. Presence of organic matter on treatment surface did not significantly affect PL decontamination efficacy, nor did growth of PL-treated bacteria on selective agar diminish survival compared to similarly treated bacteria inoculated and enumerated on nonselective agar plates. Conclusions:, Critical inter-related factors affecting the effective and repeatable in vitro decontamination performance of PL were identified during this study that will aid further development of this athermal process technology for applications in health care and in industry. Very rapid reductions (c. 7 log10 CFU cm,2 within ,10 pulses) occurred using discharge energy of 20 J for all tested clinically relevant bacteria under study when treated at 8 cm distance from xenon light source. While no resistant flora is expected to develop for treatment of microbial pathogens on two-dimensional surfaces, careful consideration of scale up factors such as design and operational usage of this PL technique will be required to assure operator safety. Significance and Impact of the Study:, Findings and conclusions derived from this study will enable further development and optimization of this decontamination technique in health care and in food preparation settings, and will advance the field of nonthermal processing technologies. [source] Spatial and temporal habitat use of kob antelopes (Kobus kob kob, Erxleben 1777) in the Comoé National Park, Ivory Coast as revealed by radio trackingAFRICAN JOURNAL OF ECOLOGY, Issue 3 2001Frauke Fischer Abstract Spatial and temporal habitat use of kob antelopes (Kobus kob kob) have been investigated in the Comoé National Park (Ivory Coast, West Africa) by use of radio telemetry. A total of 23 kob were equipped with radio collars and radio tracked for up to 15 months. Home ranges of males were smaller and those of females larger than expected from theoretical models. Adult males used smaller areas than adult females and did not show seasonal home range shifts. Daily distances travelled did not differ between sexes. Kob walked less during the night than by day and covered shorter distances in the wet season. Whereas an increase in home range overlap between females resulted in higher rates of association among individuals, association of adults of mixed sexes was not correlated with the degree of home range overlap. Territorial behaviour of males and predator avoidance by females are suggested to explain the sex-specific differences in home range size of adults and the deviation from the predicted sizes. Predator avoidance is presumed as the main reason for the reduced walking distances at night as well as in the wet season. Reproductive behaviour and feeding ecology are assumed to determine the degree of association of conspecifics. Résumé On a étudié par radio-télémétrie l'utilisation spatiale et temporelle de l'habitat par les cobes (Kobus kob kob) au Parc National de Comoé (en Côte d'Ivoire, Afrique de l'Ouest). On a équipé un total de 23 cobes de colliers radio et on les a suivis pendant 15 mois (pour certains). L'espace vital des mâles était plus petit et celui des femelles plus grand que ce à quoi on s'attendait d'après les modèles théoriques. Les mâles adultes couvraient une zone plus réduite que les femelles adultes et ne déplaçaient pas leur espace vital en fonction des saisons. Les distances parcourues chaque jour étaient les mêmes pour les deux sexes. Les cobes se déplaçaient moins la nuit que le jour, et couvraient de plus courtes distances pendant la saison des pluies. Alors qu'une augmentation du recouvrement entre espaces vitaux des femelles aboutissait à un taux supérieur d'associations entre individus, l'association d'adultes des deux sexes n'était pas liée au taux de recouvrement des espaces vitaux. On suggère que le comportement territorial des mâles et l'évitement des prédateurs par les femelles pourraient expliquer les différences, spécifiques au sexe, de la dimension de l'espace vital des adultes et la déviation par rapport aux dimensions prévues. On suppose que l'évitement des prédateurs est la raison principale de la limitation des déplacements de nuit ainsi qu'en saison des pluies. On suppose que le comportement reproducteur et l'écologie alimentaire déterminent le degré d'association entre membres de la même espèce. [source] Energetics and morphology of sockeye salmon: effects of upriver migratory distance and elevationJOURNAL OF FISH BIOLOGY, Issue 3 2004G. T. Crossin Depending on population, wild Fraser River sockeye salmon Oncorhynchus nerka travel distances of <100 km to >1100 km and ascend elevations ranging from near sea-level to 1200 m to reach spawning areas. Populations embarking on distant, high elevation migrations (i.e. Early Stuart, Chilko and Horsefly populations) began their upriver spawning migrations with higher densities of somatic energy (c. 9·2 to 9·8 MJ kg,1) and fewer eggs (c. 3200 to 3800) than populations making shorter, low elevation migrations (i.e. Weaver and Adams; c. 7·1 to 8·3 MJ kg,1 gross somatic energy and c. 4300 to 4700 eggs). Populations making difficult upriver migrations also had morphologies that were smaller and more fusiform than populations making less difficult migrations, traits that may facilitate somatic energy conservation by reducing transport costs. Indeed, fish travelling long distances expended less somatic energy per unit of migratory difficulty than those travelling shorter distances (2·8 to 3·8 kJ v. 10,1400 kJ). Consistent with evolutionary theory, difficult migrations appear to select for energy efficiency but ultimately fish making more difficult migrations produce fewer eggs, even when differences in body length have been accounted for. Despite large among-population differences in somatic energy at the start of upriver migration, all populations completed migration and spawning, and subsequently died, with c. 4 MJ kg,1 of energy remaining, a level which may reflect a threshold to sustain life. [source] Spatial patterns of Indian serial burglars with relevance to geographical profilingJOURNAL OF INVESTIGATIVE PSYCHOLOGY AND OFFENDER PROFILING, Issue 2 2006Sudhanshu Sarangi Abstract Earlier studies in Western countries have shown remarkably consistent spatial patterns in serial offenders, mainly for serious crimes notably serial killing and rape, but also (although with less clear patterns) for burglary. The universality of such spatial patterns are of theoretical interest in contributing to our understanding of criminal spatial behaviour and have practical significance for the possibility of using geographic profiling in developing countries. As such, burglars in India provide a particularly interesting test of the generality of the observed spatial consistencies. Information was therefore obtained on the offence location choices of 30 burglars, committing 150 offences in the Rourkela and Keonjhar districts of India. The home to crime distances were compared with those from developed countries, revealing similar but slightly shorter distances. In addition, the domocentricity of criminal spatial activity, reflected in the ,marauder' model (Canter & Gregory 1994) was tested through examination of the Canter Circle hypothesis, the mean interpoint distances (as they related to average distances from home), and the home base ,search costs' using a geographical profiling system (Dragnet). Overall the study found that the spatial patterns of the sample of Indian Burglars were not very different from their counterparts in the UK, North America and Australia, showing that the areas in which an offender is active tend to be shaped by, and, relatedly, close to, where he or she lives, irrespective of the part of the world in which this is. These results suggest that geographical profiling systems such as Dragnet would be productively used on the Indian sub-continent. The results also contribute to our understanding of possible universalities in offender spatial behaviour. Copyright © 2006 John Wiley & Sons, Ltd. [source] Post-breeding migrations of newts (Triturus cristatus and T. marmoratus) with contrasting ecological requirementsJOURNAL OF ZOOLOGY, Issue 3 2000R. Jehle Abstract Two newt species with contrasting ecological requirements (Triturus cristatus and T. marmoratus) were radio-tracked after leaving a shared breeding pond in western France. Movements of 30 individuals were recorded over 491 days. During the first terrestrial night, the newts migrated with high directionality up to 137 m to their refuges. Burrows of small mammals were among the favourite refuges. Movements after the first night were mostly underground and over shorter distances (< 6.8 m). Sixty-four per cent of all tracked newts stayed within 20 m of the pond edge, and migrations were recorded up to 146 m away from the pond. Both species preferred areas with bushes, hedgerows and trees, and avoided pastures and open areas. Migration in the direction of a habitat type characterized by trees and underground shelters was favoured over migrations in other directions. A clear terrestrial niche separation between the two newt species was not observed. The results are discussed in relation to previous findings that T. cristatus supersedes T. marmoratus as a consequence of anthropogenic change to the terrestrial environment, affecting the species differentially. [source] The comparative phylogeography of Neotropical mammals: patterns of intraspecific mitochondrial DNA variation among bats contrasted to nonvolant small mammalsMOLECULAR ECOLOGY, Issue 9 2000A. D. Ditchfield Abstract The major aim of this study was to compare the phylogeographic patterns of codistributed bats and small nonvolant Neotropical mammals. Cytochrome b sequences (mitochondrial DNA) were obtained for a total of 275 bats representing 17 species. The tissue samples were collected in coastal Brazil, and were available from Mexico and the Guyana. The study concentrates on four species (Artibeus lituratus, Carollia perspicillata, Sturnira lilium and Glossophaga soricina) which were well represented. The other 13 species were sequenced to test the generality of the patterns observed. In general, sequence divergence values within species were low, with most bat species presenting less than 4% average sequence divergence, and usually between 1 and 2.5%. Clades of highly similar haplotypes enjoyed broad distribution on a continental scale. These clades were not usually geographically structured, and at a given locality the number of haplotypes was high (8,10). As distance increased, some moderately divergent clades were found, although the levels of divergence were low. This suggests a geographical effect that varied depending on species and scale. Small nonvolant mammals almost invariably have high levels of sequence divergence (> 10%) for cytochrome b over much shorter distances (< 1000 km). The grain of intraspecific variation found in small nonvolant mammals is much finer than in bats. Low levels of geographical structuring cannot be attributed to a slower evolutionary rate of bat DNA in relation to other mammalian taxa. The phylogeographic pattern of bats contrasts sharply with the pattern found for Neotropical rodents and marsupials. [source] Behavioral adaptations to heat stress and water scarcity in white-faced capuchins (Cebus capucinus) in Santa Rosa National Park, Costa RicaAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 1 2009Fernando A. Campos Abstract We examined thermoregulatory behaviors in a wild population of white-faced capuchins (Cebus capucinus) inhabiting a highly seasonal dry forest in Santa Rosa National Park (SRNP), Costa Rica. The dry season in SRNP lasts ,5 months and is characterized by high ambient temperatures regularly exceeding 37°C, low relative humidity, and the near absence of precipitation. This study demonstrates that capuchins rest more and travel shorter distances during the hottest and driest hours of the day, and suggests that they extend their tongues to lower body temperature via evaporative cooling. Seasonal weather patterns and group movement data reported here are based on 940 h of observations on three social groups of capuchins (wet season: 370 h, dry season: 570 h). In the dry season, the proportion of time spent resting increased at higher temperatures whereas the proportion of time spent traveling decreased. Distance traveled between location points taken at half-hour intervals decreased significantly as temperature increased, although the correlation was not strong. Capuchins exposed their tongues during hot, dry, windy conditions, and this behavior was much more frequent in the dry season. Temperature was significantly higher and humidity significantly lower for "tongue-out" events than expected for a random event in the dry season. Finally, as surface water became scarce, home-range areas of heavy use became increasingly centered on the remaining permanent water sources. These results suggest that heat stress and water scarcity are significant influences on the behavior of capuchins in hot, dry conditions. Am J Phys Anthropol, 2009. © 2008 Wiley-Liss, Inc. [source] Across-line SNP association study of innate and adaptive immune response in laying hensANIMAL GENETICS, Issue 1 2010F. Biscarini Summary The aim of the present study was to detect quantitative trait loci (QTL) for innate and adaptive immunity in laying hens. For this purpose, the associations between 1022 single nucleotide polymorphism (SNP) markers and immune traits were studied in 583 hens from nine different layer lines. Immune traits were natural antibodies for keyhole limpet haemocyanin (KLH) and lipopolysaccharide (LPS) at 20, 40 and 65 weeks, acquired antibodies to the vaccinal virus of Newcastle disease at 20 weeks, and complement activity measured on sheep and bovine red blood cells at 20, 40 and 65 weeks. We adopted a novel approach based on across-line analysis and testing of the SNP-by-line interaction. Among lines, linkage disequilibrium is conserved at shorter distances than in individual lines; therefore, SNPs significantly associated with immune traits across lines are expected to be near the functional mutations. In the analysis, the SNPs that had a significant across-line effect but did not show significant SNP-by-line interaction were identified to test whether the association was consistent in the individual lines. Ultimately, 59 significant associations between SNPs and immune traits were detected. Our results confirmed some previously identified QTL and identified new QTL potentially involved in the immune function. We found evidence for a role of IL17A (chromosome 3) in natural and acquired antibody titres and in the classical and alternative pathways of complement activation. The major histocompatibility genes on chromosome 16 showed significant association with natural and acquired antibody titres and classical complement activity. The IL12B gene on chromosome 13 was associated with natural antibody titres. [source] The geographic structure of morphological variation in eight species of fiddler crabs (Ocypodidae: genus Uca) from the eastern United States and MexicoBIOLOGICAL JOURNAL OF THE LINNEAN SOCIETY, Issue 1 2010MELANIE J. HOPKINS Species with larger geographic distributions are more likely to encounter a greater variety of environmental conditions and barriers to gene flow than geographically-restricted species. Thus, even closely-related species with similar life-history strategies might vary in degree and geographic structure of variation if they differ in geographic range size. In the present study, we investigated this using samples collected across the geographic ranges of eight species of fiddler crabs (Crustacea: Uca) from the Atlantic and Gulf coasts of North America. Morphological variation in the carapace was assessed using geometric morphometric analysis of 945 specimens. Although the eight Uca species exhibit different degrees of intraspecific variation, widespread species do not necessarily exhibit more intraspecific or geographic variation in carapace morphology. Instead, species with more intraspecific variation show stronger morphological divergence among populations. This morphological divergence is partly a result of allometric growth coupled with differences in maximum body size among populations. On average, 10% of total within-species variation is attributable to allometry. Possible drivers of the remaining morphological differences among populations include gene flow mediated by ocean currents and plastic responses to various environmental stimuli, with isolation-by-distance playing a less important role. The results obtained indicate that morphological divergence among populations can occur over shorter distances than expected based on dispersal potential. © 2010 The Linnean Society of London, Biological Journal of the Linnean Society, 2010, 100, 248,270. [source] Allergic rhinitis in children: environmental factorsCLINICAL & EXPERIMENTAL ALLERGY REVIEWS, Issue 1 2004Y. Okamoto Summary Increasing numbers of patients with allergic rhinitis are being noted on a global scale. Over 90% of Japanese patients with perennial allergic rhinitis show allergic reaction to the mite antigen and major pollen allergens such as Japanese cedar and Japanese cypress, which are carried long distances (> 100 km) by wind and hence can produce substantial harmful effects even in metropolitan areas. This situation is distinct from that in the West, where the most common anemophilous allergen, ragweed, travels much shorter distances of up to only several hundred metres. Environmental factors such as increased antigen, air pollution, diet, intestinal microflora, decreased incidence of infections, smoking, breastfeeding and vaccination may play important roles in the development and manifestation of allergic rhinitis in genetically predisposed subjects. In particular, in newborn infants, who carry the Th2 predominant state, environmental factors may greatly affect the development of balanced production of Th1 and Th2 cytokines. However, the contribution of any environmental factor to the postnatal development of allergic rhinitis has not been sufficiently determined. A better understanding of the processes involved may lead directly to better treatment or cure of allergic rhinitis. [source] | |||||||||||||||||||||||||