267 resultados para Argentine ant -- Behavior


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PCR methods are reliable and suitable to in situ identify dermatophytes, yeasts and non dermatophyte moulds (NDM) in onychomycosis. Onychomycosis insensitive to standard treatment with topical agents as well as with oral terbinafine or itraconazole revealed Fusarium spp., Acremonium spp. and Aspergillus spp. as infectious agents. However, NDM onychomycosis could be efficiently cured using topical amphotericin B. In conclusion, correct fungal species identification is important in onychomycoses in order to prescribe adequate treatments since dermatophytes and moulds have different sensitivities to antifungal drugs.

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1. The gene Pgm-3 (or a closely linked gene) influences the phenotype and reproductive success of queens in multiple-queen (polygynous) colonies but not single-queen (monogynous) colonies of the Fire Ant Solenopsis invicta. 2. We investigated the mechanisms of differential phenotypic expression of Pgm-3 in these alternate social forms. Mature winged queens with the homozygous genotype Pgm-3(a/a) averaged 26% heavier than queens with the genotypes Pgm-3(a/b) and Pgm 3(b/b) in the polygynous form. Heterozygotes were slightly heavier (2%) than Pgm-3(b/b) queens in this form, demonstrating that the allele Pgm-3(a) is not completely recessive in its effects on weight. 3. There was no significant difference in weight among queens of the three Pgm-3 genotypes in the monogynous form, with the mean weight of monogynous queens slightly greater than that of polygynous Pgm-3(a/a) queens. Differences in weight between queens of the two social forms and among queens of the three genotypes in the polygynous form are not evident at the pupal stage and thus appear to develop during sexual maturation of the adults. This suggests that some component of the social environment of polygynous colonies inhibits weight gains during queen maturation and that Pgm-(3a/a) queens are relatively less sensitive to this factor. 4. To test whether the high cumulative queen pheromone level characteristic of polygynous colonies is the factor responsible for the differential queen maturation, we compared phenotypes of winged queens reared in split colonies in which pheromone levels were manipulated by adjusting queen number. Queens produced in colony fragments made monogynous were heavier than those produced in polygynous fragments, a finding consistent with the hypothesis that pheromone level affects the reproductive development of queens. However, genotype-specific differences in weights of queens were similar between the two treatments, suggesting that pheromone level was not the key factor of the social environment responsible for the gene-environment interaction. 5. To test whether limited food availability to winged queens associated with the high brood/worker ratios in polygynous colonies is the factor responsible for this interaction, similar split-colony experiments were performed. Elevated brood/worker ratios decreased the weight of winged queens but there was no evidence that this treatment intensified differential weight gains among queens with different Pgm-3 genotypes. Manipulation of the amount of food provided to colonies had no effect on queen weight. 6. The combined data indicate that cumulative pheromone level and brood/worker ratio are two of the factors responsible for the differences in reproductive phenotypes between monogynous and polygynous winged queens but that these factors are not directly responsible for inducing the phenotypic effects of Pgm-3 in polygynous colonies.

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Intraspecific variability in social organization is common, yet the underlying causes are rarely known. In the fire ant Solenopsis invicta, the existence of two divergent forms of social organization is under the control of a single Mendelian genomic element marked by two variants of an odorant-binding protein gene. Here we characterize the genomic region responsible for this important social polymorphism, and show that it is part of a pair of heteromorphic chromosomes that have many of the key properties of sex chromosomes. The two variants, hereafter referred to as the social B and social b (SB and Sb) chromosomes, are characterized by a large region of approximately 13 megabases (55% of the chromosome) in which recombination is completely suppressed between SB and Sb. Recombination seems to occur normally between the SB chromosomes but not between Sb chromosomes because Sb/Sb individuals are non-viable. Genomic comparisons revealed limited differentiation between SB and Sb, and the vast majority of the 616 genes identified in the non-recombining region are present in the two variants. The lack of recombination over more than half of the two heteromorphic social chromosomes can be explained by at least one large inversion of around 9 megabases, and this absence of recombination has led to the accumulation of deleterious mutations, including repetitive elements in the non-recombining region of Sb compared with the homologous region of SB. Importantly, most of the genes with demonstrated expression differences between individuals of the two social forms reside in the non-recombining region. These findings highlight how genomic rearrangements can maintain divergent adaptive social phenotypes involving many genes acting together by locally limiting recombination.

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Patients with the early-onset Alzheimer's disease P117L mutation in the presenilin-1 gene (PS-1) present pathological hallmarks in the hippocampus, the frontal cortex and the basal ganglia. In the present work we determined by immunohistochemistry which brain regions were injured in the transgenic PS-1 P117L mice, in comparison to their littermates, the B6D2 mice. Furthermore, as these regions are involved in novelty detection, we investigated the behavior of these mice in tests for object and place novelty recognition. Limited numbers of senile plaques and neurofibrillary tangles were detected in aged PS-1 P117L mice in the CA1 only, indicating that the disease is restrained to an initial neuropathological stage. Western blots showed a change in PSD-95 expression (p=0.03), not in NR2A subunit, NR2B subunit and synaptophysin expressions in the frontal cortex, suggesting specific synaptic alterations. The behavioral tests repeatedly revealed, despite a non-significant preference for object or place novelty, maladaptive exploratory behavior of the PS-1 P117L mice in novel environmental conditions, not due to locomotor problems. These mice, unlike the B6D2 mice, were less inhibited to visit the center of the cages (p=0.01) and they continued to move excessively in the presence of a displaced object (p=0.021). Overall, the PS-1 P117L mice appear to be in an initial Alzheimer's disease-like neuropathological stage, and they showed a lack of reaction toward novel environmental conditions.

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In social insects the number of queens per nest varies greatly. One of the proximate causes of this variation may be that queens produced by multiple-queen colonies are generally smaller, and might thus be unable to found new colonies independently. We examined whether the social origin of queens and males influenced the colony-founding success of queens in the socially polymorphic ant Formica selysi. Queens originating from single-queen and multiple-queen colonies had similar survival rates and colony-founding success, be they alone or in two-queen associations. During the first 5 months, queens originating from single-queen colonies gave rise to more workers than queens originating from multiple-queen colonies. Pairs of queens were also more productive than single queens. However, these differences in productivity were transient, as all types of colonies had reached a similar size after 15 months. Mating between social forms was possible and did not decrease queen survival or colony productivity, compared to mating within social forms. Overall, these results indicate that queens from each social form are able to found colonies independently, at least under laboratory conditions. Moreover, gene flow between social forms is not restricted by mating or genetic incompatibilities. This flexibility in mating and colony founding helps to explain the maintenance of alternative social structures in sympatry and the absence of genetic differentiation between social forms.

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Utilization behavior (UB) consists of reaching out and using objects in the environment in an automatic manner and out of context. This behavior has been correlated to frontal lobe dysfunction, especially of the right hemisphere. We describe a 60-year-old woman, affected by a glioblastoma located in the right frontal region, who presented with intermittent UB of the mobile phone as the main clinical manifestation of partial complex status epilepticus. Video/EEG studies showed a striking correlation between mobile phone utilization and ictal epileptic activity. Clinical and EEG findings were markedly reduced after the introduction of antiepileptic drugs. This case study suggests that UB may be added to the symptoms described for partial seizures originating from frontal areas.

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Afin d'étudier l'influence du nombre de reines par colonie sur les processus de reconnaissance, nous avons effectué des tests d'attraction d'ouvrières envers des reines homo et hétérocoloniales. Ces tests ont démontré que le niveau d'attraction des ouvrières était plus élevé envers les reines homocoloniales qu'envers les reines hétérocoloniales, ce qui démontre que les ouvrières sont capables de discriminer entre les deux types de reines. Cette discrimination résulte de l'apprentissage par les ouvrières de l'odeur coloniale probablement juste après l'émergence ou même peut-être avant. Dans nos expériences, les reines étaient vraisemblablement une source importante de cette odeur coloniale. La comparaison entre des sociétés expérimentales monogynes et polygynes a montré que les processus de reconnaissance étaient perturbés en sociétés polygynes. Ces résultats nous amènent à formuler l'hypothèse qu'en sociétés polygynes, le mélange de plusieurs complexes phéromonaux produits par chacune des reines entraîne une odeur coloniale moins spécifique qu'en société monogyne où il y a production d'un complexe phéromonal royal unique. Ces résultats sont discutés par rapport aux autres implications de la polygynie et tout particulièrement la perte d'agressivité entre individus de différentes colonies chez I. humilis et d'autres espèces de fourmis polygynes.

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BACKGROUND: Patient behavior accounts for half or more of the variance in health, disease, mortality and treatment outcome and costs. Counseling using motivational interviewing (MI) effectively improves the substance use and medical compliance behavior of patients. Medical training should include substantial focus on this key issue of health promotion. The objective of the study is to test the efficacy of teaching MI to medical students. METHODS: Thirteen fourth-year medical students volunteered to participate. Seven days before and after an 8-hour interactive MI training workshop, each student performed a video-recorded interview with two standardized patients: a 60 year-old alcohol dependent female consulting a primary care physician for the first time about fatigue and depression symptoms; and a 50 year-old male cigarette smoker hospitalized for myocardial infarction. All 52 videos (13 students×2 interviews before and after training) were independently coded by two blinded clinicians using the Motivational Interviewing Training Integrity (MITI, 3.0). MITI scores consist of global spirit (Evocation, Collaboration, Autonomy/Support), global Empathy and Direction, and behavior count summary scores (% Open questions, Reflection to question ratio, % Complex reflections, % MI-adherent behaviors). A "beginning proficiency" threshold (BPT) is defined for each of these 9 scores. The proportion of students reaching BPT before and after training was compared using McNemar exact tests. Inter-rater reliability was evaluated by comparing double coding, and test-retest analyses were conducted on a sub-sample of 10 consecutive interviews by each coder. Weighted Kappas were used for global rating scales and intra-class correlations (ICC) were computed for behavior count summary scores. RESULTS: The percent of counselors reaching BPT before and after MI training increased significantly for Evocation (15% to 65%, p<.001), Collaboration (27% to 77%, p=.001), Autonomy/Support (15% to 54%, p=.006), and % Open questions (4% to 38%, p=.004). Proportions increased, but were not statistically significant for Empathy (38% to 58%, p=.18), Reflection to question ratio (0% to 15%, p=.12), % Complex reflection (35% to 54%, p=.23), and % MI-adherent behaviors (8% to 15%, p=.69). There was virtually no change for the Direction scale (92% to 88%, p=1.00). The reliability analyses produced mixed results. Weighted kappas for inter-rater reliability ranged from .14 for Direction to .51 for Collaboration, and from .27 for Direction to .80 for Empathy for test-retest. ICCs ranged from .20 for Complex reflections to .89 for Open questions (inter-rater), and from .67 for Complex reflections to .99 for Reflection to question ratio (test-retest). CONCLUSION: This pilot study indicates that a single 8-hour training in motivational interviewing for voluntary fourth-year medical students results in significant improvement of some MI skills. A larger sample of randomly selected medical students observed over longer periods should be studied to test if MI training generalizes to medical students. Inter-rater reliability and test-retest findings indicate a need for caution when interpreting the present results, as well as for more intensive training to help appropriately capture more dimensions of the process in future studies.

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A fundamental trait of the human self is its continuum experience of space and time. Perceptual aberrations of this spatial and temporal continuity is a major characteristic of schizophrenia spectrum disturbances--including schizophrenia, schizotypal personality disorder and schizotypy. We have previously found the classical Perceptual Aberration Scale (PAS) scores, related to body and space, to be positively correlated with both behavior and temporo-parietal activation in healthy participants performing a task involving self-projection in space. However, not much is known about the relationship between temporal perceptual aberration, behavior and brain activity. To this aim, we composed a temporal Perceptual Aberration Scale (tPAS) similar to the traditional PAS. Testing on 170 participants suggested similar performance for PAS and tPAS. We then correlated tPAS and PAS scores to participants' performance and neural activity in a task of self-projection in time. tPAS scores correlated positively with reaction times across task conditions, as did PAS scores. Evoked potential mapping and electrical neuroimaging showed self-projection in time to recruit a network of brain regions at the left anterior temporal cortex, right temporo-parietal junction, and occipito-temporal cortex, and duration of activation in this network positively correlated with tPAS and PAS scores. These data demonstrate that schizotypal perceptual aberrations of both time and space, as reflected by tPAS and PAS scores, are positively correlated with performance and brain activation during self-projection in time in healthy individuals along the schizophrenia spectrum.

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Understanding levels of population differentiation and inbreeding are important issues in conservation biology, especially for social Hymenoptera with fragmented and small population sizes. Isolated populations are more vulnerable to genetic loss and extinction than those with extended continuous distributions. However, small populations are not always a consequence of a recent reduction of their habitat. Thus, determining the history of population isolation and current patterns of genetic variation of a species is crucial for its conservation. Rossomyrmex minuchae is a slave-making ant with patchy distribution in South Eastern Spain and is classified as vulnerable by the IUCN. In contrast, the other three known species of the genus are presumed to show more uniform distributions. Here we investigate the genetic diversity and population structure of R. minuchae and compare it with that found in two other species of the genus: R. anatolicus and R. quandratinodum. We conclude that although genetic diversity of R. minuchae is low, there is no evidence of a recent bottleneck, suggesting a gradual and natural fragmentation process. We also show extreme population differentiation at nuclear and mitochondrial markers, and isolation by distance at a local scale. Despite some evidence for inbreeding and low genetic variation within populations, we found almost no diploid males, a finding which contrasts with that expected in inbred Hymenoptera with single locus complementary sex determination. This could mean that sex is determined by another mechanism. We argue that continued low population size means that detrimental effects of inbreeding and low genetic variation are likely in the future. We suggest that a policy of artificial gene flow aimed at increasing within population variation is considered as a management option.

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Following the recent avian influenza and pandemic (H1N1) 2009 outbreaks, public trust in medical and political authorities is emerging as a new predictor of compliance with officially recommended protection measures. In a two-wave longitudinal survey of adults in French-speaking Switzerland, trust in medical organizations longitudinally predicted actual vaccination status 6 months later, during the pandemic (H1N1) 2009 vaccination campaign. No other variables explained significant amounts of variance. Trust in medical organizations also predicted perceived efficacy of officially recommended protection measures (getting vaccinated, washing hands, wearing a mask, sneezing into the elbow), as did beliefs about health issues (perceived vulnerability to disease, threat perceptions). These findings show that in the case of emerging infectious diseases, actual behavior and perceived efficacy of protection measures may have different antecedents. Moreover, they suggest that public trust is a crucial determinant of vaccination behavior and underscore the practical importance of managing trust in disease prevention campaigns.

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Asexual reproduction is particularly common among introduced species, probably because it helps to overcome the negative effects associated with low population densities during colonization. The ant Cerapachys biroi has been introduced to tropical and subtropical islands around the world since the beginning of the last century. In this species, workers can reproduce via thelytokous parthenogenesis. Here, we use genetic markers to reconstruct the history of anthropogenic introductions of C. biroi, and to address the prevalence of female parthenogenesis in introduced and native populations. We show that at least four genetically distinct lineages have been introduced from continental Asia and have led to the species' circumtropical establishment. Our analyses demonstrate that asexual reproduction dominates in the introduced range and is also common in the native range. Given that C. biroi is the only dorylomorph ant that has successfully become established outside of its native range, this unusual mode of reproduction probably facilitated the species' worldwide spread. On the other hand, the rare occurrence of haploid males and at least one clear case of sexual recombination in the introduced range show that C. biroi has not lost the potential for sex. Finally, we show that thelytoky in C. biroi probably has a genetic rather than an infectious origin, and that automixis with central fusion is the most likely underlying cytological mechanism. This is in accordance with what is known for other thelytokous eusocial Hymenoptera.