72 resultados para Behavior and Behavior Mechanisms


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This study aimed to compare and contrast how midwives working in either hospital or community settings are currently responding to the cooccurrence of domestic and child abuse (CA), their perceived role and willingness to identify abuse, record keeping, reporting of suspected or definite cases of CA and training received. A survey questionnaire was sent to 861 hospital and community midwives throughout Northern Ireland which resulted in 488 midwives completing the questionnaire, leading to a 57% response rate. Comparisons were made using descriptive statistics and cross-tabulation, and the questionnaire was validated using exploratory factor analysis. Community midwives reported receiving more training on domestic and CA. Although a high percent of both hospital and community midwives acknowledged a link between domestic violence (DV) and CA, it was the community midwives who encountered more suspected and definite (P <0.001) cases of CA. More community midwives reported to be aware of the mechanisms for reporting CA. However, an important finding is that although 12% of community midwives encountered a definite case of CA, only 2% reported the abuse, leaving a 10% gap between reporting and identifying definite cases of CA. Findings suggest that lack of education and training was a problem as only a quarter of hospital-based midwives reported to have received training on DV and 40% on CA. This was significantly less than that received by community midwives, as 57% received training on DV, and 62% on CA. The study suggests that midwives need training on how to interact with abused mothers using non-coercive, supportive and empowering mechanisms. Many women may not spontaneously disclose the issues of child or domestic abuse in their lives, but often respond honestly to a sensitively asked question. This issue is important as only 13% of the sample actually asked a woman a direct question about DV.

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The complex dynamics of ionization and excitation mechanisms in capacitively coupled radio-frequency plasmas is discussed for single- and dual-frequency operations in low-pressure and atmospheric pressure plasmas. Electrons are energized through the dynamics of electric fields in the vicinity of the plasma boundary sheaths. Distinctly different power dissipation mechanisms can either co-exist or initiate mode transitions exhibiting characteristic spatio-temporal ionization structures. Phase resolved optical emission spectroscopy, in combination with adequate modelling of the population dynamics of excited states, and numerical simulations reveal dissipation associated with sheath expansion, sheath collapse, transient electron avalanches and wave–particle interactions. In dual-frequency systems the relative phase between the two frequency components provides additional strategies to tailor the plasma dynamics.

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A comprehensive experimental study was performed to identify and discriminate mechanisms contributing to passive intermodulation (PIM) in microstrip transmission lines. The effects of strip length and width, and substrate materials on PIM performance of printed lines were investigated in the GSM900, DCS1800 and UMTS frequency bands. The major features of the experiment design, sample preparation and test setup are discussed in detail. The measurement results have demonstrated that the PIM level cumulatively grows on the longer microstrip lines and decreases on wider strips and, thus, indicated that the distributed resistive nonlinearity of the printed traces represents the dominant mechanism of intermodulation generation in the printed lines on PTFE-based substrates. © 2009 The Institution of Engineering and Technology.

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Various contaminants which can be aerobically degraded find their way directly or indirectly into surface water bodies. The reaeration coefficient (K2) characterises the rate at which oxygen can transfer from the atmosphere across the air-water interface following oxygen depletion in a water body. Other mechanisms (like advection, dispersion and transient storage) determine how quickly the contaminants can spread in the water, affecting their spatial and temporal concentrations. Tracer methods involving injection of a gas into the water body have traditionally been used for direct (in-situ) measurement of K2 in a given reach. This paper shows how additional modelling of tracer test results can be used to quantify also hydrodynamic mechanisms (e.g. dispersion and storage exchange coefficients, etc.). Data from three tracer tests conducted in the River Lagan (Northern Ireland) using an inert gas (krypton, Kr) are re-analysed using two solute transport models (ADM, TSM) and an inverse-modelling framework (OTIS-P). Results for K2 are consistent with previously published values for this reach (K2(20)~10-40 d-1). The storage area constituted 30-60% of the main cross-section area and the storage exchange rate was between 2.5×10-3-3.2×10-3s-1. The additional hydrodynamic parameters obtained give insight into transport and dispersion mechanisms within the reach.

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Direct pharmacological targeting of the anti-apoptotic B-cell lymphoma-2 (BCL-2) family is an attractive therapeutic strategy for treating cancer. Obatoclax is a pan-BCL-2 family inhibitor currently in clinical development. Here we show that, although obatoclax can induce mitochondrial apoptosis dependent on BCL-2 associated x protein/BCL-2 antagonist killer (BAX/BAK) consistent with its on-target pharmacodynamics, simultaneous silencing of both BAX and BAK did not abolish acute toxicity or loss of clonogenicity. This is despite complete inhibition of apoptosis. Obatoclax dramatically reduced viability without inducing loss of plasma membrane integrity. This was associated with rapid processing of light chain-3 (LC3) and reduction of S6 kinase phosphorylation, consistent with autophagy. Dramatic ultrastructural vacuolation, not typical of autophagy, was also induced. Silencing of beclin-1 failed to prevent LC3 processing, whereas knockout of autophagy-related (Atg) 7 abolished LC3 processing but failed to prevent obatoclax-induced loss of clonogenicity or ultrastructural changes. siRNA silencing of Atg7 in BAX/BAK knockout mouse embryonic fibroblasts did not prevent obatoclax-induced loss of viability. Cells selected for obatoclax resistance evaded apoptosis independent of changes in BCL-2 family expression and displayed reduced LC3 processing. In summary, obatoclax exhibits BAX- and BAK-dependent and -independent mechanisms of toxicity and activation of autophagy. Mechanisms other than autophagy and apoptosis are blocked in obatoclax resistant cells and contribute significantly to obatoclax's anticancer efficacy. Cell Death and Disease (2010) 1, e108; doi:10.1038/cddis.2010.86; published online 16 December 2010

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Substantial sums of money are invested annually in preventative medicine and therapeutic treatment for people with a wide range of physical and psychological health problems, sometimes to no avail. There is now mounting evidence to suggest that companion animals, such as dogs and cats, can enhance the health of their human owners and may thus contribute significantly to the health expenditure of our country. This paper explores the evidence that pets can contribute to human health and well-being. The article initially concentrates on the value of animals for short- and long-term physical health, before exploring the relationship between animals and psychological health, focusing on the ability of dogs, cats, and other species to aid the disabled and serve as a "therapist" to those in institutional settings. The paper also discusses the evidence for the ability of dogs to facilitate the diagnosis and treatment of specific chronic diseases, notably cancer, epilepsy, and diabetes. Mechanisms underlying the ability of animals to promote human health are discussed within a theoretical framework. Whereas the evidence for a direct causal association between human well-being and companion animals is not conclusive, the literature reviewed is largely supportive of the widely held, and long-standing, belief that "pets are good for us." © 2009 The Society for the Psychological Study of Social Issues.

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Countless numbers of insects migrate within and between continents every year, and yet we know very little about the ultimate reasons and proximate mechanisms that would explain these mass movements. Here we suggest that perhaps the most important reason for insects to migrate is to hedge their reproductive bets. By spreading their breeding efforts in space and time, insects distribute their offspring over a range of environmental conditions. We show how the study of individual long-distance movements of insects may contribute to a better understanding of migration. In the future, advances in tracking methods may enable the global surveillance of large insects such as desert locusts.

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This paper analyses the interaction between neoliberal inspired reforms of public services and the mechanisms for achieving public accountability. Where once accountability was exercised through the ballot box, now in the neoliberal age managerial and market based forms of accountability predominate. The analysis identifies resistance from civil society campaigns to the neoliberal restructuring of public services which leads to public accountability (PA) becoming a contested arena. To develop this analysis a re-theorisation of PA, as a relationship where civil society seeks to control the state, is explored in the context of social housing in England over the past thirty years. Central to this analysis is a dialogical analysis of key documents from a social housing regulator and civil society campaign. The analysis shows that the current PA practices are an outcome of both reforms from the government and resistance from civil society (in the shape of tenants’ campaigns). The outcome of which is to tell the story of the changes in PA (and accountability) centring on an analysis of discourse. Thus, the paper moves towards answering the question – what has happened to PA during the neoliberal age?

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The classic, non-photochemical blue bottle experiment involves the reaction of methylene blue (MB) with deprotonated glucose, to form a bleached form of the dye, leuco-methylene blue (LMB), and subsequent colour recovery by shaking with air. This reaction is a popular demonstrator of key principles in kinetics and reaction mechanisms. Here it is modified so as to highlight features of homogenous and heterogeneous photoinduced electron transfer (PET) (Pure Appl. Chem., 2007, 79, 293-465) reactions, i.e. blue bottle light experiments. The homogeneous blue bottle light experiment uses methylene blue, MB, as the photo-sensitizer and triethanolamine as the sacrificial electron donor. Visible light irradiation of this system leads to its rapid bleaching, followed by the ready restoration of its original colour upon shaking away from the light source. The heterogeneous blue bottle light experiment uses titania as the photo-sensitizer, MB as a redox indicator and glucose as the sacrificial electron donor. UVA light irradiation of this system leads to the rapid bleaching of the MB and the gradual restoration of its original colour with shaking and standing. The latter 'dark' step can be made facile and more demonstrator-friendly by using platinised titania particles. These two photochemical versions of the blue bottle experiment are used to explore the factors which underpin homogeneous and heterogeneous PET reactions and provide useful demonstrations of homogeneous and heterogeneous photochemistry.

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Historically, peptidergic substances (in the form of neurosecretions) were linked to moulting in nematodes. More recently, there has been a renewal of interest in nematode neurobiology, initially triggered by studies demonstrating the localization of peptide immunoreactivities to the nervous system. Here, David Brownlee, Ian Fairweather, Lindy Holden-Dye and Robert Walker will review progress on the isolation of nematode neuropeptides and efforts to unravel their physiological actions and inactivation mechanisms. Future avenues for research are suggested and the potential exploitation of peptidergic pathways in future therapeutic strategies highlighted.

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In studies of radiation-induced DNA fragmentation and repair, analytical models may provide rapid and easy-to-use methods to test simple hypotheses regarding the breakage and rejoining mechanisms involved. The random breakage model, according to which lesions are distributed uniformly and independently of each other along the DNA, has been the model most used to describe spatial distribution of radiation-induced DNA damage. Recently several mechanistic approaches have been proposed that model clustered damage to DNA. In general, such approaches focus on the study of initial radiation-induced DNA damage and repair, without considering the effects of additional (unwanted and unavoidable) fragmentation that may take place during the experimental procedures. While most approaches, including measurement of total DNA mass below a specified value, allow for the occurrence of background experimental damage by means of simple subtractive procedures, a more detailed analysis of DNA fragmentation necessitates a more accurate treatment. We have developed a new, relatively simple model of DNA breakage and the resulting rejoining kinetics of broken fragments. Initial radiation-induced DNA damage is simulated using a clustered breakage approach, with three free parameters: the number of independently located clusters, each containing several DNA double-strand breaks (DSBs), the average number of DSBs within a cluster (multiplicity of the cluster), and the maximum allowed radius within which DSBs belonging to the same cluster are distributed. Random breakage is simulated as a special case of the DSB clustering procedure. When the model is applied to the analysis of DNA fragmentation as measured with pulsed-field gel electrophoresis (PFGE), the hypothesis that DSBs in proximity rejoin at a different rate from that of sparse isolated breaks can be tested, since the kinetics of rejoining of fragments of varying size may be followed by means of computer simulations. The problem of how to account for background damage from experimental handling is also carefully considered. We have shown that the conventional procedure of subtracting the background damage from the experimental data may lead to erroneous conclusions during the analysis of both initial fragmentation and DSB rejoining. Despite its relative simplicity, the method presented allows both the quantitative and qualitative description of radiation-induced DNA fragmentation and subsequent rejoining of double-stranded DNA fragments. (C) 2004 by Radiation Research Society.

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We have previously demonstrated that remote ischemic preconditioning (IPC) by instigation of three cycles of 10-min occlusion/reperfusion in a hindlimb of the pig elicits an early phase of infarct protection in local and distant skeletal muscles subjected to 4 h of ischemia immediately after remote IPC. The aim of this project was to test our hypothesis that hindlimb remote IPC also induces a late phase of infarct protection in skeletal muscle and that K(ATP) channels play a pivotal role in the trigger and mediator mechanisms. We observed that pig bilateral latissimus dorsi (LD) muscle flaps sustained 46 +/- 2% infarction when subjected to 4 h of ischemia/48 h of reperfusion. The late phase of infarct protection appeared at 24 h and lasted up to 72 h after hindlimb remote IPC. The LD muscle infarction was reduced to 28 +/- 3, 26 +/- 1, 23 +/- 2, 24 +/- 2 and 24 +/- 4% at 24, 28, 36, 48 and 72 h after remote IPC, respectively (P <0.05; n = 8). In subsequent studies, hindlimb remote IPC or intravenous injection of the sarcolemmal K(ATP) (sK(ATP)) channel opener P-1075 (2 microg/kg) at 24 h before 4 h of sustained ischemia (i.e., late preconditioning) reduced muscle infarction from 43 +/- 4% (ischemic control) to 24 +/- 2 and 19 +/- 3%, respectively (P <0.05, n = 8). Intravenous injection of the sK(ATP) channel inhibitor HMR 1098 (6 mg/kg) or the nonspecific K(ATP) channel inhibitor glibenclamide (Glib; 1 mg/kg) at 10 min before remote IPC completely blocked the infarct- protective effect of remote IPC in LD muscle flaps subjected to 4 h of sustained ischemia at 24 h after remote IPC. Intravenous bolus injection of the mitochondrial K(ATP) (mK(ATP)) channel inhibitor 5-hydroxydecanoate (5-HD; 5 mg/kg) immediately before remote IPC and 30-min intravenous infusion of 5-HD (5 mg/kg) during remote IPC did not affect the infarct-protective effect of remote IPC in LD muscle flaps. However, intravenous Glib or 5-HD, but not HMR 1098, given 24 h after remote IPC completely blocked the late infarct-protective effect of remote IPC in LD muscle flaps. None of these drug treatments affected the infarct size of control LD muscle flaps. The late phase of infarct protection was associated with a higher (P <0.05) muscle content of ATP at the end of 4 h of ischemia and 1.5 h of reperfusion and a lower (P <0.05) neutrophilic activity at the end of 1.5 h of reperfusion compared with the time-matched control. In conclusion, these findings support our hypothesis that hindlimb remote IPC induces an uninterrupted long (48 h) late phase of infarct protection, and sK(ATP) and mK(ATP) channels play a central role in the trigger and mediator mechanism, respectively.

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Mycorrhizal associations, including ericoid, arbuscular and ecto-mycorrhizas, are found colonising highly metal contaminated soils. How do mycorrhizal fungi achieve metal resistance, and does this metal resistance confer enhanced metal resistance to plant symbionts? These are the questions explored in this review by considering the mechanistic basis of mycorrhizal adaptation to metal cations. Recent molecular and physiological studies are discussed. The review reappraises what constitutes metal resistance in the context of mycorrhizal associations and sets out the constitutive and adaptive mechanisms available for mycorrhizas to adapt to contaminated sites. The only direct evidence of mycorrhizal adaptation to metal cation pollutants is the exudation of organic acids to alter pollutant availability in the rhizosphere. This is not to say that other mechanism of adaptation do not exist, but conclusive evidence of adaptive mechanisms of tolerance are lacking. For constitutive mechanisms of resistance, there is much more evidence, and mycorrhizas possess the same constitutive mechanisms for dealing with metal contaminants as other organisms. Rhizosphere chemistry is critical to understanding the interactions of mycorrhizas with polluted soils. Soil pH, mineral weathering, pollutant precipitation with plant excreted organic acids all may have a key role in constitutive and adaptive tolerance of mycorrhizal associations present on contaminated sites. The responses of mycorrhizal fungi to toxic metal cations are diverse. This, linked to the fact that mycorrhizal diversity is normally high, even on highly contaminated sites, suggests that this diversity may have a significant role in colonisation of contaminated sites by mycorrhizas. That is, the environment selects for the fungal community that can best cope with the environment, so having diverse physiological attributes will enable colonisation of a wide range of metal contaminated micro-habitats.