909 resultados para Aggressive
Resumo:
We present the global general circulation model IPSL-CM5 developed to study the long-term response of the climate system to natural and anthropogenic forcings as part of the 5th Phase of the Coupled Model Intercomparison Project (CMIP5). This model includes an interactive carbon cycle, a representation of tropospheric and stratospheric chemistry, and a comprehensive representation of aerosols. As it represents the principal dynamical, physical, and bio-geochemical processes relevant to the climate system, it may be referred to as an Earth System Model. However, the IPSL-CM5 model may be used in a multitude of configurations associated with different boundary conditions and with a range of complexities in terms of processes and interactions. This paper presents an overview of the different model components and explains how they were coupled and used to simulate historical climate changes over the past 150 years and different scenarios of future climate change. A single version of the IPSL-CM5 model (IPSL-CM5A-LR) was used to provide climate projections associated with different socio-economic scenarios, including the different Representative Concentration Pathways considered by CMIP5 and several scenarios from the Special Report on Emission Scenarios considered by CMIP3. Results suggest that the magnitude of global warming projections primarily depends on the socio-economic scenario considered, that there is potential for an aggressive mitigation policy to limit global warming to about two degrees, and that the behavior of some components of the climate system such as the Arctic sea ice and the Atlantic Meridional Overturning Circulation may change drastically by the end of the twenty-first century in the case of a no climate policy scenario. Although the magnitude of regional temperature and precipitation changes depends fairly linearly on the magnitude of the projected global warming (and thus on the scenario considered), the geographical pattern of these changes is strikingly similar for the different scenarios. The representation of atmospheric physical processes in the model is shown to strongly influence the simulated climate variability and both the magnitude and pattern of the projected climate changes.
Resumo:
This paper examines the extent to which engineers can influence the competitive behavior of bidders in Best Value or multi-attribute construction auctions, where both the (dollar) bid and technical non-price criteria are scored according to a scoring rule. From a sample of Spanish construction auctions with a variety of bid scoring rules, it is found that bidders are influenced by the auction rules in significant and predictable ways. The bid score weighting, bid scoring formula and abnormally low bid criterion are variables likely to influence the competitiveness of bidders in terms of both their aggressive/conservative bidding and concentration/dispersion of bids. Revealing the influence of the bid scoring rules and their magnitude on bidders’ competitive behavior opens the door for the engineer to condition bidder competitive behavior in such a way as to provide the balance needed to achieve the owner’s desired strategic outcomes.
Resumo:
Progress Report from the Strategic Sanctuary for the Destruction of Free Will presents a new work combining film, music and installation that juxtaposes the setting of the institution with the aesthetics of psychedelia.Progress Report from the Strategic Sanctuary for the Destruction of Free Will is an installation, film and sound work that takes over the gallery. Using plain white card, it distorts the structure of the gallery’s architecture, producing a paranoid shrunken space. Inside this space, performers in cardboard costumes re-enact abstracted, broken gestures drawn from video documentation of acid trips, psychedelic dancing, rehab sessions and radical psychotherapy workshops. Progress Report from the Strategic Sanctuary for the Destruction of Free Will has been formed through Pil and Galia Kollectiv’s research into the anti-psychiatry movement, their interests in counter cultural movements and their studies around biopolitics and the proliferation of societal medication. In 1958, having had a life changing experience with LSD, former alcoholic Charles Dederich founded Synanon, a drug rehabilitation program based on residential care and an aggressive form of group therapy called ‘The Game’. The organisation gradually evolved into a controversial alternative community, described in a critical pamphlet as creating Strategic Sanctuaries for the Destruction of Free Will, “a subversive program for mixing delinquents and lefties”. In 1984, anti-psychiatrist R. D. Laing described tranquillizers as chemical straight jackets. With our growing understanding of the plasticity of the brain and the potential to shape it, the tension between liberation and control in the struggle over the mind continues to define our relationship to labour, culture and production. Interrogating these ideas, the exhibition poses the question of whether a collective body can overcome the solipsism of the incommunicable experience of the individual mind.
Resumo:
Mechanisms and consequences of the effects of estrogen on the brain have been studied both at the fundamental level and with therapeutic applications in mind. Estrogenic hormones binding in particular neurons in a limbic-hypothalamic system and their effects on the electrophysiology and molecular biology of medial hypothalamic neurons were central in establishing the first circuit for a mammalian behavior, the female-typical mating behavior, lordosis. Notably, the ability of estradiol to facilitate transcription from six genes whose products are important for lordosis behavior proved that hormones can turn on genes in specific neurons at specific times, with sensible behavioral consequences. The use of a gene knockout for estrogen receptor alpha (ERalpha) revealed that homozygous mutant females simply would not do lordosis behavior and instead were extremely aggressive, thus identifying a specific gene as essential for a mammalian social behavior. In dramatic contrast, ERbeta knockout females can exhibit normal lordosis behavior. With the understanding, in considerable mechanistic detail, of how the behavior is produced, now we are also studying brain mechanisms for the biologically adaptive influences which constrain reproductive behavior. With respect to cold temperatures and other environmental or metabolic circumstances which are not consistent with successful reproduction, we are interested in thyroid hormone effects in the brain. Competitive relations between two types of transcription factors - thyroid hormone receptors and estrogen receptors have the potential of subserving the blocking effects of inappropriate environmental circumstances on female reproductive behaviors. TRs can compete with ERalpha both for DNA binding to consensus and physiological EREs and for nuclear coactivators. In the presence of both TRs and ERs, in transfection studies, thyroid hormone coadministration can reduce estrogen-stimulated transcription. These competitive relations apparently have behavioral consequences, as thyroid hormones will reduce lordosis, and a TRbeta gene knockout will increase it. In sum, we not only know several genes that participate in the selective control of this sex behavior, but also, for two genes, we know the causal routes. Estrogenic hormones are also the foci of widespread attention for their potential therapeutic effects improving, for example, certain aspects of mood and cognition. The former has an efficient animal analog, demonstrated by the positive effects of estrogen in the Porsolt forced swim test. The latter almost certainly depends upon trophic actions of estrogen on several fundamental features of nerve cell survival and growth. The hypothesis is raised that the synaptic effects of estrogens are secondary to the trophic actions of this type of hormone in the nucleus and nerve cell body.
Resumo:
The study was carried out to clarify the nature of symptomless infection by Botrytis cinerea and to what extent it differs from aggressive necrotic infection in Lactuca sativa (lettuce) and Arabidopsis thaliana. Symptomless plants were produced by dry spore inoculation in plants growing in controlled environmental conditions or in glasshouses. Plating out of surface-disinfected and non-surface-disinfected samples of inoculated, apparently healthy, plants on selective medium revealed that the fungus was spreading from the initial inoculation site to newly developing plant organs both internally and externally. Similar findings were obtained in microscope experiments in which host plants were inoculated with GFP labelled B. cinerea and symptomless spreading was monitored under confocal laser scanning microscope. Spore germination on leaf surface was followed by development of sub-cuticular vesicles and plant cell damage in the infected epidermal cell and a few nearby cells. Sparsely branched long hyphae arose from the vesicles and spread on the leaf surface; spread was mostly on the outer surface of the epidermal layer but occasionally below the cuticle or epidermal cells. In the late symptomless phase, mycelium arising from single vesicles formed several mycelial networks on leaves. Experiments were carried out to compare the extent of gene expression in symptomless and necrotic infections, using RT-qPCR. Expression of selected genes was quantified in tissue samples based on the amount of mRNA of the respective genes found. In both host species, the mRNA concentration of signalling genes bcg1, bmp1 and calcineurin, and the pathogenicity genes bcsod1 and bcpg1 were similar to or slightly greater in symptomless samples than in necrotic samples. The mRNA of the signalling gene bac and pathogenicity genes bcbot1 and bcnep1, were not detected or detected in lower abundance than in necrosis. In lettuce, the leaves developing distant from the site of inoculation showed similar results to A. thaliana, but in healthy leaves close to the site of inoculation mRNA concentrations of bac and bcnep1 were similar to necrotic samples. Thus, in both host species, the fungus grew along with the plant and moved to newly growing plant parts without producing symptoms; during this growth some pathogenicity genes were less expressed than in necrotic infection.
Resumo:
Botrytis species are generally considered to be aggressive, necrotrophic plant pathogens. By contrast to this general perception, however, Botrytis species could frequently be isolated from the interior of multiple tissues in apparently healthy hosts of many species. Infection frequencies reached 50% of samples or more, but were commonly less, and cryptic infections were rare or absent in some plant species. Prevalence varied substantially from year to year and from tissue to tissue, but some host species routinely had high prevalence. The same genotype was found to occur throughout a host, representing mycelial spread. B. cinerea and B. pseudocinerea are the species that most commonly occur as cryptic infections, but phylogenetically distant isolates of Botrytis were also detected, one of which does not correspond to previously described species. Sporulation and visible damage occurred only when infected tissues were stressed, or became mature or senescent. There was no evidence of cryptic infection having a deleterious effect on growth of the host, and prevalence was probably greater in plants grown in high light conditions. Isolates from cryptic infections were often capable of causing disease (to varying extents) when spore suspensions were inoculated onto their own host as well as on distinct host species, arguing against co-adaptation between cryptic isolates and their hosts. These data collectively suggest that several Botrytis species, including the most notorious pathogenic species, exist frequently in cryptic form to an extent that has thus far largely been neglected, and do not need to cause disease on healthy hosts in order to complete their life-cycles.
Resumo:
The purpose of this study was to evaluate the effect of a single application of antimicrobial photodynamic therapy (aPDT) on microbiological profile and cytokine pattern in dogs. Periodontal disease was induced by placing 3.0 silk ligatures around the mandibular pre-molars bilaterally during 8 weeks. The dogs were randomly treated with aPDT using a dye/laser system, scaling and root planning (SRP), or with the association of treatments (SRP + aPDT). Plaque samples were collected at baseline, 1, 3, and 4 weeks, and the mean counts of 40 species were determined using DNA-DNA hybridization. Gingival biopsies were removed and the expression of tumor necrosis factor alpha (TNF-alpha), receptor activator of NF-kB ligand (RANKL), osteoprotegerin (OPG), matrix metalloproteinase (MMP-1), interleukin (IL) 6, IL-10 and total bacterial load by analysis of 16 S rRNA gene were evaluated through real-time PCR. The results shows that the levels of the majority of the species were reduced 1 week post-therapy for all treatments, however, an increase in counts of Prevotella intermedia (p = 0.00), Prevotella. nigrescens (p = 0.00) and Tannerella forsythia (p = 0.00) was observed for aPDT and SRP + aPDT. After 4 weeks, a regrowth of Porphyromonas gingivalis (p = 0.00) and Treponema denticola (p = 0.00), was observed for all treatments. Also, a strikingly reduction of counts on counts of Aggregatibacter actinomycetemcomitans was observed for the aPDT (p = 0.00). For the cytokine pattern, the results were similar for all treatments, and a reduction in the expression of cytokines and bacterial load was observed throughout the study. Our results suggest that SRP, aPDT in a single application, and SRP + aPDT affects different bacterial species and have similar effects on the expression of cytokines evaluated during the treatment of ligature-induced periodontitis.
Resumo:
Objectives: (1) To compare the anatomopathological variables and recurrence rates in patients with early-stage adenocarcinoma (AC) and squamous cell carcinoma (SCC) of the uterine cervix; (2) to identify the independent risk factors for recurrence. Study design: This historical cohort study assessed 238 patients with carcinoma of the uterine cervix (113 and IIA), who underwent radical hysterectomy with pelvic lymph node dissection between 1980 and 1999. Comparison of category variables between the two histological types was carried out using the Pearson`s X-2 test or Fisher exact test. Disease-free survival rates for AC and SCC were calculated using the Kaplan-Meier method and the curves were compared using the log-rank test. The Cox proportional hazards model was used to identify the independent risk factors for recurrence. Results: There were 35 cases of AC (14.7%) and 203 of SCC (85.3%). AC presented lower histological grade than did SCC (grade 1: 68.6% versus 9.4%; p < 0.001), lower rate of lymphovascular space involvement (25.7% versus 53.7%; p = 0.002), lower rate of invasion into the middle or deep thirds of the uterine cervix (40.0% versus 80.8%; p < 0.001) and lower rate of lymph node metastasis (2.9% versus 16.3%; p = 0.036). Although the recurrence rate was lower for AC than for SCC (11.4% versus 15.8%), this difference was not statistically significant (p = 0.509). Multivariate analysis identified three independent risk factors for recurrence: presence of metastases in the pelvic lymph nodes, invasion of the deep third of the uterine cervix and absence of or slight inflammatory reaction in the cervix. When these variables were adjusted for the histological type and radiotherapy status, they remained in the model as independent risk factors. Conclusion: The AC group showed less aggressive histological behavior than did the SCC group, but no difference in the disease-free survival rates was noted. (C) 2006 Elsevier Ireland Ltd. All rights reserved.
Resumo:
The present work evaluated the effects of accelerated carbonation on mechanical and physical characteristics of cementitious roofing tiles reinforced with vegetable fibre. The maximum load and toughness of the tiles have increased approximately 25% and 80% respectively as a consequence of the accelerated carbonation. Water absorption and apparent porosity decreased with carbonation while bulk density increased as a clear indication of the densification of the composite. The improvement on the mechanical performance suggests that the fibres retained their tensile strength in the inorganic matrix. Results of specimens extracted from the tested tiles after approximately 480 days in laboratory environment and further aged indicate that soak and dry cycles promoted some leaching of hydration products and more voids and lower density when performed before carbonation. The results indicate the utilization of accelerated carbonation as an effective procedure to mitigate the degradation suffered by the cellulose fibres in the less aggressive medium. (C) 2009 Elsevier Ltd. All rights reserved.
Resumo:
Intense male-male competition for females may drive the evolution of male morphological dimorphism, which is frequently associated with alternative mating tactics. Using modern techniques for the detection of discontinuous allometries, we describe male dimorphism in the Neotropical harvestman Longiperna concolor, the males of which use their elongated, sexually dimorphic legs IV in fights for the possession of territories where females lay eggs. We also tested three predictions related to the existence of alternative mating tactics: (1) if individuals with relatively longer legs IV (majors) are more likely to monopolize access to reproductive resources, they are expected to remain close to stable groups of females more than individuals with relatively shorter legs IV (minors) do; (2) if minors achieve fertilization by moving between territories, they are expected to be less faithful to specific sites; and (3) majors should be observed in aggressive interactions more often. We individually marked all the individuals from a population of Longiperna during the reproductive season and recorded the location of each sighting for males and females as well as the identity of males involved in fights. Majors were more likely to have harems, and large majors were even more likely to do so. Majors were more philopatric and all males involved in fights belonged to this morph. These results strongly suggest that the mating tactic of the majors is based on resource defense whereas that of the minors probably relies on sneaking into the territories of the majors and furtively copulating with females.
Resumo:
Competition for floral resources is a key force shaping pollinator communities, particularly among social bees. The ability of social bees to recruit nestmates for group foraging is hypothesized to be a major factor in their ability to dominate rich resources such as mass-flowering trees. We tested the role of group foraging in attaining dominance by stingless bees, eusocial tropical pollinators that exhibit high diversity in foraging strategies. We provide the first experimental evidence that meliponine group foraging strategies, large colony sizes and aggressive behavior form a suite of traits that enable colonies to improve dominance of rich resources. Using a diverse assemblage of Brazilian stingless bee species and an array of artificial ""flowers"" that provided a sucrose reward, we compared species` dominance and visitation under unrestricted foraging conditions and with experimental removal of group-foraging species. Dominance does not vary with individual body size, but rather with foraging group size. Species that recruit larger numbers of nestmates (Scaptotrigona aff. depilis, Trigona hyalinata, Trigona spinipes) dominated both numerically (high local abundance) and behaviorally (controlling feeders). Removal of group-foraging species increased feeding opportunities for solitary foragers (Frieseomelitta varia, Melipona quadrifasciata and Nannotrigona testaceicornis). Trigona hyalinata always dominated under unrestricted conditions. When this species was removed, T. spinipes or S. aff. depilis controlled feeders and limited visitation by solitary-foraging species. Because bee foraging patterns determine plant pollination success, understanding the forces that shape these patterns is crucial to ensuring pollination of both crops and natural areas in the face of current pollinator declines.
Resumo:
Stingless bees (Meliponini) construct their own species-specific nest entrance. The size of this entrance is under conflicting selective pressures. Smaller entrances are easier to defend; however, a larger entrance accommodates heavier forager traffic. Using a comparative approach with 26 species of stingless bees, we show that species with greater foraging traffic have significantly larger entrances. Such a strong correlation between relative entrance area and traffic across the different species strongly suggests a trade-off between traffic and security. Additionally, we report on a significant trend for higher forager traffic to be associated with more guards and for those guards to be more aggressive. Finally, we discuss the nest entrance of Partamona, known in Brazil as boca de sapo, or toad mouth, which has a wide outer entrance but a narrow inner entrance. This extraordinary design allows these bees to finesse the defensivity/traffic trade-off.
Resumo:
A first case of subsociality is reported for the genus Latrodectus. Individuals were found sharing the same web and feeding together. In captivity they showed mutual tolerance and communal feeding. This finding is remarkable for two reasons. First, widow spiders, even compared with other spiders, are famously aggressive and cannibalistic so that social behavior in the genus was unexpected. Second, the genus nests outside the ""Anelosimus + lost colulus"" clade where all the other social theridiids are found.
Resumo:
Melanoma is the most aggressive form of skin cancer, and its incidence has increased dramatically over the years. The murine B16F10 melanoma in syngeneic C57Bl/6 mice has been used as a highly aggressive model to investigate tumor development. Presently, we demonstrate in the B16F10-Nex2 subclone that silencing of SOCS-1, a negative regulator of Jak/Stat pathway, leads to reversal of the tumorigenic phenotype and inhibition of melanoma cell metastasis. SOCS-1 silencing with short hairpin RNA affected tumor growth and cell cycle regulation with arrest at the S phase with large-sized nuclei, reduced cell motility, and decreased melanoma cell invasion through Matrigel. A clonogenic assay showed that SOCS-1 acted as a modulator of resistance to anoikis. In addition, down-regulation of SOCS-1 decreased the expression of epidermal growth factor receptor ( mainly the phosphorylated-R), Ins-R alpha, and fibroblast growth factor receptor. In vivo, silencing of SOCS-1 inhibited subcutaneous tumor growth and metastatic development in the lungs. Because SOCS-1 is expressed in most melanoma cell lines and bears a relation with tumor invasion, thickness, and stage of disease, the present results on the effects of SOCS-1 silencing in melanoma suggest that this regulating protein can be a target of cancer therapy.
Resumo:
Nandrolone is an anabolic-androgenic steroid (AAS) that is highly abused by individuals seeking enhanced physical strength or body appearance. Supraphysiological doses of this synthetic testosterone derivative have been associated with many physical and psychiatric adverse effects, particularly episodes of impulsiveness and overt aggressive behavior. As the neural mechanisms underlying AAS-induced behavioral disinhibition are unknown, we investigated the status of serotonergic system-related transcripts in several brain areas of mice receiving prolonged nandrolone administration. Male C57BL/6J mice received 15 mg/kg of nandrolone decanoate subcutaneously once daily for 28 days, and different sets of animals were used to investigate motor-related and emotion-related behaviors or 5-HT-related messenger RNA (mRNA) levels by real-time quantitative polymerase chain reaction. AAS-injected mice had increased body weight, were more active and displayed anxious-like behaviors in novel environments. They exhibited reduced immobility in the forced swim test, a higher probability of being aggressive and more readily attacked opponents. AAS treatment substantially reduced mRNA levels of most investigated postsynaptic 5-HT receptors in the amygdala and prefrontal cortex. Interestingly, the 5-HT(1B) mRNA level was further reduced in the hippocampus and hypothalamus. There was no alteration of 5-HT system transcript levels in the midbrain. In conclusion, high doses of AAS nandrolone in male mice recapitulate the behavioral disinhibition observed in abusers. Furthermore, these high doses downregulate 5-HT receptor mRNA levels in the amygdala and prefrontal cortex. Our combined findings suggest these areas as critical sites for AAS-induced effects and a possible role for the 5-HT(1B) receptor in the observed behavioral disinhibition.