924 resultados para Aggressive behavior in animals
Resumo:
WNS-affected bats did so over similar time frames as WNSunaffected bats. The behaviors of bats with WNS did not change as drastically as expected. Thereseems to be little to no effect on their ability to fly/forage until much later stages of the disease when they are likely near death. WNS-affected bats are grooming more which could be altering the way they use energy reserves during hibernation possibly leading tostarvation and eventually death. The decreased likelihood of arousals in response to external cues may be the result of spending more energy during previous and increasingly frequent arousals. While it is clear that WNS does result in changes in behavior whether these changes are directly in response to fungal skin infection or to some other component of the syndrome such as decreased energy availability or loss of homeostasis is unknown. bat behavior, white-nose syndrome, behavior, video surveillance, arousal patterns White-Nose Syndrome (WNS) is a disease of hibernating bats caused by the fungal pathogen Geomyces destructans. The fungus, which was first noted in 2006, invades bats wings and other exposed membranes, eventually resulting in death. Researchers have yet to understand many aspects of this disease, including basic etiology and epidemiology. There is also a lack of information on how fungal infection may change the behavior of healthy bats during hibernation or how changes in behavior may influence disease progression. Based upon the physiological changes that are known to occur in affected bats, and upon anecdotal observations of aberrant behavior in these bats, I hypothesized that WNS would significantly change the behavior of the little brown myotis (Myotis lucifugus). My research examined the behavior of hibernating bats during arousals from torpor. I compared WNS-affected and unaffected bats, in the field and incaptivity, using motion-sensitive infrared cameras. Flight maneuverability and echolocation were also tested between WNS-affected and unaffected bats during arousalsfrom hibernation to detect changes in the bats' ability to perform basic locomotion or potentially catch insect prey. Lastly, hibernating bats were artificially disturbed and theirarousal patterns were monitored to examine changes in the response to external stimuli between WNS-affected and unaffected bats.Bats with WNS groomed for longer periods of time after arousing from torpor, both in the field and in captivity. They also engaged in longer periods of any sort of activity during these arousals. There were no changes in acoustical signaling during flight tests and changes in flight maneuverability were only found in bats were seen staging" near the entrance of the mine which is itself a unique behavior exhibited by affected bats. At this point these bats were likely near death and could barely fly at all. In response toexternal stimuli bats with WNS were less likely to arouse than unaffected bats. However when they did arouse WNS-affected bats did so over similar time frames as WNSunaffected bats. The behaviors of bats with WNS did not change as drastically as expected. Thereseems to be little to no effect on their ability to fly/forage until much later stages of the disease when they are likely near death. WNS-affected bats are grooming more which could be altering the way they use energy reserves during hibernation possibly leading tostarvation and eventually death. The decreased likelihood of arousals in response to external cues may be the result of spending more energy during previous and increasingly frequent arousals. While it is clear that WNS does result in changes in behavior whetherthese changes are directly in response to fungal skin infection or to some other component of the syndrome such as decreased energy availability or loss of homeostasis is unknown."
Resumo:
Studies using factor analysis have helped describe the organization of copulatory behavior in male rodents. However, the focus of these studies on a few traditional measures may have limited their results. To test this possibility, 74 sexually-experienced male hamsters were observed as they copulated with stimulus females. The measures collected exceeded the conventional ones in number, variety and independence. The factor analysis of these data revealed a structure with seven factors collectively accounting for 80% of the variance. Most resembled the factors in previous reports, reinforcing the contributions that the processes suggested by these factors make to the organization,of male behavior. But several other factors were more novel, possibly reflecting the use of measures that were novel or revised for greater independence. The most interesting of these were two factors focusing on early steps in the progression leading to ejaculation. Importantly, both incorporated measures from each of the three copulatory series that were observed. Past work suggests that independent processes control the times required to initiate copulation and later resume it after an ejaculation. In contrast, these results suggest the existence of two processes, each of which contributes to both the initiation and reinitiation of copulation. (C) 2014 Elsevier B.V. All rights reserved.
Resumo:
Impulsivity is a multifaceted construct that defines a range of maladaptive behavioral styles. The present research aimed to identify different dimensions of impulsive behavior in adolescents from a battery of laboratory behavioral assessments. In one analysis, correlations were examined between two self report and seven laboratory behavioral measures of impulsivity. The correlation between the two self report measures was high compared to correlations between the self report and laboratory behavioral measures. In a second analysis, a principal components analysis was performed with just the laboratory behavioral measures. Three behavioral dimensions were identified -- "impulsive decision-making", "impulsive inattention", and "impulsive disinhibition". These dimensions were further evaluated using the same sample with a confirmatory factor analysis, which did support the hypothesis that these are significant and independent dimensions of impulsivity. This research indicates there are at least three separate subtypes of impulsive behavior when using laboratory behavioral assessments with adolescent participants.
Resumo:
Open-ended interviews of 90 min length of 38 patients were analyzed with respect to speech stylistics, shown by Schucker and Jacobs to differentiate individuals with type A personality features from those with type B. In our patients, Type A/B had been assessed by the Bortner Personality Inventory. The stylistics studied were: repeated words swallowed words, interruptions, simultaneous speech, silence latency (between question and answer) (SL), speed of speech, uneven speed of speech (USS), explosive words (PW), uneven speech volume (USV), and speech volume. Correlations between both raters for all speech categories were high. Positive correlations between extent of type A and SL (r = 0.33; p = 0.022), USS (r = 0.51; p = 0.002), PW (r = 0.46; p = 0.003) and USV (r = 0.39; p = 0.012) were found. Our results indicate that the speech in nonstress open-ended interviews of type A individuals tends to show a higher emotional tension (positive correlations for USS PW and USV) and is more controlled in conversation (positive correlation for SL).
Resumo:
A mass‐balance model for Lake Superior was applied to polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and mercury to determine the major routes of entry and the major mechanisms of loss from this ecosystem as well as the time required for each contaminant class to approach steady state. A two‐box model (water column, surface sediments) incorporating seasonally adjusted environmental parameters was used. Both numerical (forward Euler) and analytical solutions were employed and compared. For validation, the model was compared with current and historical concentrations and fluxes in the lake and sediments. Results for PCBs were similar to prior work showing that air‐water exchange is the most rapid input and loss process. The model indicates that mercury behaves similarly to a moderately‐chlorinated PCB, with air‐water exchange being a relatively rapid input and loss process. Modeled accumulation fluxes of PBDEs in sediments agreed with measured values reported in the literature. Wet deposition rates were about three times greater than dry particulate deposition rates for PBDEs. Gas deposition was an important process for tri‐ and tetra‐BDEs (BDEs 28 and 47), but not for higher‐brominated BDEs. Sediment burial was the dominant loss mechanism for most of the PBDE congeners while volatilization was still significant for tri‐ and tetra‐BDEs. Because volatilization is a relatively rapid loss process for both mercury and the most abundant PCBs (tri‐ through penta‐), the model predicts that similar times (from 2 ‐ 10 yr) are required for the compounds to approach steady state in the lake. The model predicts that if inputs of Hg(II) to the lake decrease in the future then concentrations of mercury in the lake will decrease at a rate similar to the historical decline in PCB concentrations following the ban on production and most uses in the U.S. In contrast, PBDEs are likely to respond more slowly if atmospheric concentrations are reduced in the future because loss by volatilization is a much slower process for PBDEs, leading to lesser overall loss rates for PBDEs in comparison to PCBs and mercury. Uncertainties in the chemical degradation rates and partitioning constants of PBDEs are the largest source of uncertainty in the modeled times to steady‐state for this class of chemicals. The modeled organic PBT loading rates are sensitive to uncertainties in scavenging efficiencies by rain and snow, dry deposition velocity, watershed runoff concentrations, and uncertainties in air‐water exchange such as the effect of atmospheric stability.
Resumo:
Langerhans cell histiocytosis, a rare disease that occurs mainly in children, may produce a broad range of manifestations, from a single osseous lesion to multiple lesions involving more than one organ or system. The clinical course varies widely in relation to the patient's age. Multisystem disease may demonstrate especially aggressive behavior in very young children, with the outcome depending largely on the stage of disease and the degree of related organ dysfunction at the time of diagnosis. Extraosseous manifestations are less commonly seen than osseous ones and may be more difficult to identify. To accurately detect extraosseous Langerhans cell histiocytosis at an early stage, radiologists must recognize the significance of individual clinical and laboratory findings as well as the relevance of imaging features for the differential diagnosis. The pattern and severity of pulmonary, thymic, hepatobiliary, splenic, gastrointestinal, neurologic, mucocutaneous, soft-tissue (head and neck), and salivary involvement in Langerhans cell histiocytosis generally are well depicted with conventional radiography, ultrasonography, computed tomography, and magnetic resonance imaging. However, the imaging features are not pathognomonic, and a biopsy usually is necessary to establish a definitive diagnosis.
Resumo:
Human behavior is a major factor modulating the consequences of road tunnel accidents. We investigated the effect of information and instruction on drivers' behavior as well as the usability of virtual environments to simulate such emergency situations. Tunnel safety knowledge of the general population was assessed using an online questionnaire, and tunnel safety behavior was investigated in a virtual reality experiment. Forty-four participants completed three drives through a virtual road tunnel and were confronted with a traffic jam, no event, and an accident blocking the road. Participants were randomly assigned to a control group (no intervention), an informed group who read a brochure containing safety information prior to the tunnel drives, or an informed and instructed group who read the same brochure and received additional instructions during the emergency situation. Informed participants showed better and quicker safety behavior than the control group. Self-reports of anxiety were assessed three times during each drive. Anxiety was elevated during and after the emergency situation. The findings demonstrate problematic safety behavior in the control group and that knowledge of safety information fosters adequate behavior in tunnel emergencies. Enhanced anxiety ratings during the emergency situation indicate external validity of the virtual environment.
Resumo:
Individuals show compensatory health behavior (e.g. safer cycling without helmet) to compensate for risky behavior. Compensatory health behavior is facilitated by high self-efficacy. A total of 134 cyclists with different helmet wearing frequencies (occasionally (OH) or never helmet (NH)) were asked to fill out a questionnaire on their compensatory health behavior when cycling without a helmet and on their general self-efficacy. An interaction between self-efficacy and use of a helmet on compensatory health behavior was found. OH-users with high self-efficacy showed more compensatory health behavior than OH-users with low self-efficacy. This effect was not present in NH-users. We assume that OH-users engage in compensatory health behavior, whereas NH-users remain unprotected by behavioral adaptation. These persons are vulnerable and may require specific attention in preventive actions.
Resumo:
Extant hominoids, including humans, are well known for their inability to swim instinctively. We report swimming and diving in two captive apes using visual observation and video recording. One common chimpanzee and one orangutan swam repeatedly at the water surface over a distance of 2-6 m; both individuals submerged repeatedly. We show that apes are able to overcome their negative buoyancy by deliberate swimming, using movements which deviate from the doggy-paddle pattern observed in other primates. We suggest that apes' poor swimming ability is due to behavioral, anatomical, and neuromotor changes related to an adaptation to arboreal life in their early phylogeny. This strong adaptive focus on arboreal life led to decreased opportunities to interact with water bodies and consequently to a reduction of selective pressure to maintain innate swimming behavior. As the doggy paddle is associated with quadrupedal walking, a deviation from terrestrial locomotion might have interfered with the fixed rhythmic action patterns responsible for innate swimming.
Resumo:
Altitudinal gradients offer valuable study systems to investigate how adap- tive genetic diversity is distributed within and between natural populations and which factors promote or prevent adaptive differentiation. The environ- mental clines along altitudinal gradients tend to be steep relative to the dispersal distance of many organisms, providing an opportunity to study the joint effects of divergent natural selection and gene flow. Temperature is one variable showing consistent altitudinal changes, and altitudinal gradi- ents can therefore provide spatial surrogates for some of the changes antici- pated under climate change. Here, we investigate the extent and patterns of adaptive divergence in animal populations along altitudinal gradients by sur- veying the literature for (i) studies on phenotypic variation assessed under common garden or reciprocal transplant designs and (ii) studies looking for signatures of divergent selection at the molecular level. Phenotypic data show that significant between-population differences are common and taxo- nomically widespread, involving traits such as mass, wing size, tolerance to thermal extremes and melanization. Several lines of evidence suggest that some of the observed differences are adaptively relevant, but rigorous tests of local adaptation or the link between specific phenotypes and fitness are sorely lacking. Evidence for a role of altitudinal adaptation also exists for a number of candidate genes, most prominently haemoglobin, and for anony- mous molecular markers. Novel genomic approaches may provide valuable tools for studying adaptive diversity, also in species that are not amenable to experimentation.