973 resultados para required work
Resumo:
Although it plays a key role in the theory of stratified turbulence, the concept of available potential energy (APE) dissipation has remained until now a rather mysterious quantity, owing to the lack of rigorous result about its irreversible character or energy conversion type. Here, we show by using rigorous energetics considerations rooted in the analysis of the Navier-Stokes for a fully compressible fluid with a nonlinear equation of state that the APE dissipation is an irreversible energy conversion that dissipates kinetic energy into internal energy, exactly as viscous dissipation. These results are established by showing that APE dissipation contributes to the irreversible production of entropy, and by showing that it is a part of the work of expansion/contraction. Our results provide a new interpretation of the entropy budget, that leads to a new exact definition of turbulent effective diffusivity, which generalizes the Osborn-Cox model, as well as a rigorous decomposition of the work of expansion/contraction into reversible and irreversible components. In the context of turbulent mixing associated with parallel shear flow instability, our results suggests that there is no irreversible transfer of horizontal momentum into vertical momentum, as seems to be required when compressible effects are neglected, with potential consequences for the parameterisations of momentum dissipation in the coarse-grained Navier-Stokes equations.
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This paper raises methodological issues about the challenges and dilemmas of inclusive research practices reflecting on the work of an advisory group carrying out research on using Information and Communication Technology (ICT) to enhance community participation. The interests of three parties can be identified – the commissioning agent, the researchers and the researched – and these interplayed throughout the course of the research determining the outcomes. Given the relationship between inclusive research and advocacy, there were particular gains in enabling the voice of the advisory group to shape the way in which the research was conducted and to disseminate the findings both within the organisation and beyond. However, the fragility of these new structures required organisational changes for the research to be truly empowering. The experience of the group suggests the need for their involvement at all stages of the research process
Resumo:
Thyroid hormone receptors (TR) are hormone-dependent transcription regulators that play a major role in human health, development, and metabolic functions. The thyroid hormone resistance syndrome, diabetes, obesity, and some types of cancer are just a few examples of important diseases that are related to TR malfunctioning, particularly impaired hormone binding. Ligand binding to and dissociation from the receptor ultimately control gene transcription and, thus, detailed knowledge of binding and release mechanisms are fundamental for the comprehension of the receptor`s biological function and development of pharmaceuticals. In this work, we present the first computational study of ligand entry into the ligand binding domain (LBD) of a nuclear receptor. We report molecular dynamics simulations of ligand binding to TRs using a generalization of the steered molecular dynamics technique designed to perform single-molecule pulling simulations along arbitrarily nonlinear driving pathways. We show that only gentle protein movements and conformational adaptations are required for ligand entry into the LBDs and that the magnitude of the forces applied to assist ligand binding are of the order of the forces involved in ligand dissociation. Our simulations suggest an alternative view for the mechanisms ligand binding and dissociation of ligands from nuclear receptors in which ligands can simply diffuse through the protein surface to reach proper positioning within the binding pocket. The proposed picture indicates that the large-amplitude protein motions suggested by the apo- and holo-RXR alpha crystallographic structures are not required, reconciling conformational changes of LBDs required for ligand entry with other nuclear receptors apo-structures that resemble the ligand-bound LBDs.
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In the work described in the present paper, an analytical solution of the general heat conduction equation was employed to assay the temperature profile inside a solid slab which is initially at room temperature and is suddenly plunged into a fluid maintained at a high temperature. The results were then extrapolated to a simulation of a hot modulus of rupture test of typical MgO-graphite refractory samples containing different amounts of graphite in order to evaluate how fast the temperature equilibrates inside the test specimens. Calculations indicated that, depending on the graphite content, the time to full temperature homogenization was in the range of 80 to 200 s. These findings are relevant to the high temperature testing of such refractories in oxidizing conditions in view of the graphite oxidation risks in the proper evaluation of the hot mechanical properties.
Resumo:
BACKGROUND: Organizations are increasingly required to reduce their environmental impact through the adoption of environmental management, which requires the support of human resource practices.OBJECTIVE: The objective of this study is to determine whether human resource management practices, especially training, are supporting environmental management practices at four hotels located in Brazil.METHODS: This research is qualitative, based on the analysis of four hotels in Brazil.RESULTS: Based on the systematized empirical evidence collected from four hotels (Hotels A, B, C, and D), it can be concluded that: (1) human resource management is still not fully aligned with environmental objectives at the hotels studied; (2) only Hotel B has implemented environmental management practices and aligned with human resource management in a more developed manner, which may indicate that these two variables of analysis could have interrelations; (3) environmental training as a human resource management practice was verified in all hotels analyzed.CONCLUSIONS: The greening of human resources practices is not fully aligned with environmental objectives in the hotels studied. If these hotels really wish to "go green," environmental training will be necessary. Hotel stakeholders play a major role in implementing the greening of the hotel industry.
Resumo:
Splicing of primary transcripts is an essential process for the control of gene expression. Specific conserved sequences in premature transcripts are important to recruit the spliceosome machinery. The Saccharomyces cerevisiae catalytic spliceosome is composed of about 60 proteins and 5 snRNAs (U1, U2, U4/U6 and U5). Among these proteins, there are core components and regulatory factors, which might stabilize or facilitate splicing of specific substrates. Assembly of a catalytic complex depends on the dynamics of interactions between these proteins and RNAs. Cwc24p is an essential S. cerevisiae protein, originally identified as a component of the NTC complex, and later shown to affect splicing in vivo. In this work, we show that Cwc24p also affects splicing in vitro. We show that Cwc24p is important for the U2 snRNP binding to primary transcripts, co-migrates with spliceosomes, and that it interacts with Brr2p. Additionally, we show that Cwc24p is important for the stable binding of Prp19p to the spliceosome. We propose a model in which Cwc24p is required for stabilizing the U2 association with primary transcripts, and therefore, especially important for splicing of RNAs containing non- consensus branchpoint sequences.
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The European LeukemiaNet (ELN), workpackage 10 (WP10) was designed to deal with diagnosis matters using morphology and immunophenotyping. This group aimed at establishing a consensus on the required reagents for proper immunophenotyping of acute leukemia and lymphoproliferative disorders. Animated discussions within WP10, together with the application of the Delphi method of proposals circulation, quickly led to post-consensual immunophenotyping panels for disorders on the ELN website. In this report, we established a comprehensive description of these panels, both mandatory and complementary, for both types of clinical conditions. The reason for using each marker, sustained by relevant literature information, is provided in detail. With the constant development of immunophenotyping techniques in flow cytometry and related software, this work aims at providing useful guidelines to perform the most pertinent exploration at diagnosis and for follow-up, with the best cost benefit in diseases, the treatment of which has a strong impact on health systems.
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The primary objective of this thesis is to demonstrate the pernicious impact that moral hierarchies have on our perception and subsequent treatment of non-human animals. Moral hierarchies in general are characterized by a dynamic in which one group is considered to be fundamentally superior to a lesser group. This thesis focuses specifically on the moral hierarchies that arise when humans are assumed to be superior to non-human animals in virtue of their advanced mental capabilities. The operative hypothesis of this thesis is essentially that moral hierarchies thwart the provision of justice to non-human animals in that they function as a justification for otherwise impermissible actions. When humans are assumed to be fundamentally superior to non-human animals then it becomes morally permissible for humans to kill non-human animals and utilize them as mere instrumentalities. This thesis is driven primarily by an in-depth analysis of the approaches to animal rights that are provided by Peter Singer, Tom Regan, and Gary Francione. Each of these thinkers claim that they overcome anthropocentrism and provide approaches that preclude the establishment of a moral hierarchy. One of the major findings of this thesis, however, is that Singer and Regan offer approaches that remain highly anthropocentric despite the fact that each thinker claims that they have overcome anthropocentrism. The anthropocentrism persists in these respective approaches in that each thinkers gives humans Regan and Singer have different conceptions of the criteria that are required to afford a being moral worth, but they both give preference to beings that have the cognitive ability to form desires regarding the future.. As a result, a moral hierarchy emerges in which humans are regarded to be fundamentally superior. Francione, however, provides an approach that does not foster a moral hierarchy. Francione creates such an approach by applying the principle of equal consideration of interests in a consistent manner. Moreover, Francione argues that mere sentience is both a necessary and sufficient condition for being eligible and subsequently receiving moral consideration. The upshot of this thesis is essentially that the moral treatment of animals is not compatible with the presence of a moral hierarchy. As a result, this thesis demonstrates that future approaches to animal rights must avoid the establishment of moral hierarchies. The research and analysis within this thesis demonstrates that this is not a possibility, however, unless all theories of justice that are to accommodate animals abandon the notion that cognition matters morally.
Resumo:
As a group of experienced and novice youth workers, we believe that youth work is fundamentally about building trust-filled, mutually respectful relationships with young people. We create safe environments for young people to connect with other supportive adults and peers and to avoid violence in their neighborhoods and their homes. We guide those harmed by oppressive community conditions such as racism, sexism, agism, homophobia, and classism through a process of healing. As we get to know more about young people’s interests, we help them develop knowledge and skills in a variety of areas including: academic, athletic, leadership/civic, the arts, health and wellbeing, and career exploration. In short, we create transformative experiences for young people. In spite of the critical roles we play, we have largely been overlooked in youth development research, policy, and as a professional workforce. We face challenges ‘moving up’ in our careers. We get frustrated by how little money we earn. We are discouraged that despite our knowledge and experience we are not invited to the tables where youth funding, programming, and policy decisions are made. It is true—many of us do not have formal training or degrees in youth work—a reality which at times we regret. Yet, as our colleague communicates in the accompanying passage (see below), we resent that formal education is required for us to get ahead, particularly because we question whether we need it to do our jobs more effectively. Through the “What is the Value of Youth Work?” symposium, we hope to address these concerns through a dialogue about youth work with the following objectives: • Increase awareness of the knowledge, skills, contributions, and professionalism of youth workers; • Advance a youth worker professional development model that integrates a dilemma-focused approach with principles of social justice youth development; • Launch an ongoing Worcester area Youth Worker network. This booklet provides a brief overview of the challenges in ‘professionalizing’ youth work and an alternative approach that we are advancing that puts the knowledge and expertise of youth workers at the center of professional development.
Resumo:
The Loss, grief and other problems are events that most of people experience them during their Life. The earthquake is a disaster that makes people experience loss, grief and problems simultaneously. This crisis affects on survivors as much as they face to dangers in their lives. Thus, most of them need to being supported until they can solve their problems, be relaxed and do their daily activities. We know that the profession of social workers is to assist individuals who are seeking help. But there is a Problem, how do they help the clients efficiently? Especially, those clients who have suffered earthquake. Generally, the role of social workers in helping the survivors of earthquake is significant. To this end, the present paper tries to describe the process of social casework and those skills required for social workers to help the survivors. These skills include: situational supporting, hopefulness making, consoling, assuring, concentrating, solutions developing and refer.
Resumo:
Currently, social work is witnessing a quite polarized debate about what should be the basis for good practice. Simply stated, the different attempts to define the required basis for effective and accountable interventions in social work practice can be grouped in two paradigmatic positions, which seem to be in strong opposition to each other. On the one hand the highly influential evidence based practice movement highlights the necessity to base practice interventions on proven effectiveness from empirical research. Despite some variations, such as between narrow conceptions of evidence based practice (see e.g. McNeece/Thyer, 2004) and broader approaches to it (see e.g. Gambrill, 1999, 2001, 2008), the evidence based practice movement embodies a positivist orientation and more explicitly scientific aspirations of social work by using positivistic empirical strategies. Critics of the evidence based practice movement argue that its narrow epistemological assumptions are not appropriate for the understanding of social phenomena and that evidence based guidelines to practice are insufficient to deal with the extremely complex activities social work practice requires in different and always somewhat unique practice situations (Webb, 2001; Gray & Mc Donald, 2006; Otto, Polutta &Ziegler, 2009). Furthermore critics of evidence based practice argue that it privileges an uncritical and a-political positivism which seems highly problematic in the current climate of welfare state reforms, in which the question ‘what works’ is highly politicized and the legitimacy of professional social work practice is being challenged maybe more than ever before (Kessl, 2009). Both opponents and proponents of evidence based practice argue on the epistemological, the methodological and the ethical level to sustain their point of view and raise fundamental questions about the real nature of social work practice, so that one could get the impression that social work is really at the crossroads between two very different conceptions of social work practice and its further professional development (Stepney, 2009). However, this article is not going to merely rehearse the pro and contra of different positions that are being invoked in the debate about evidence based practice. Instead it aims to go further by identifying the dilemmas underlying these positions which - so it is argued – re-emerge in the debate about evidence based practice, but which are older than this debate. They concern the fundamental ambivalence modern professionalization processes in social work were subjected to from their very beginnings.
Resumo:
Practice is subject to increasing pressure to demonstrate its ability to achieve outcomes required by public policy makers. As part of this process social work practice has to engage with issues around advancing knowledge-based learning processes in a close collaboration with education and research based perspectives. This has given rise to approaches seeking to combine research methodology, field research and practical experience. Practice research is connected to both “the science of the concrete” – a field of research oriented towards subjects more than objects and “mode 2 knowledge production” – an application-oriented research where frameworks and findings are discussed by a number of partners. Practice research is defined into two approaches: practice research – collaboration between practice and research – and practitioner research – processes controlled and accomplished by practitioners. The basic stakeholders in practice research are social workers, service users, administrators, management, organisations, politicians and researchers. Accordingly, practice research is necessarily collaborative, involving a meeting point for different views, interests and needs, where complexity and dilemmas are inherent. Instead of attempting to balance or reconcile these differences, it is important to respect the differences if collaboration is to be established. The strength of both practice and research in practice research is to address these difficult challenges. The danger for both fields is to avoid and reject them.
Resumo:
It has been demonstrated previously that the mammalian heart cannot sustain physiologic levels of pressure-volume work if ketone bodies are the only substrates for respiration. In order to determine the metabolic derangement responsible for contractile failure in hearts utilizing ketone bodies, rat hearts were prefused at a near-physiologic workload in a working heart apparatus with acetoacetate and competing or alternate substrates including glucose, lactate, pyruvate, propionate, leucine, isoleucine, valine and acetate. While the pressure-volume work for hearts utilizing glucose was stable for 60 minutes of perfusion, performance fell by 30 minutes for hearts oxidizing acetoacetate as the sole substrate. The tissue content of 2-oxoglutarate and its transamination product, glutamate, were elevated in hearts utilizing acetoacetate while succinyl-CoA was decreased suggesting impaired flux through the citric acid cycle at the level of 2-oxoglutarate dehydrogenase. Further studies indicated that the inhibition of 2-oxoglutarate dehydrogenase developed prior to the onset of contractile failure and that the inhibition of the enzyme may be related to sequestration of the required cofactor, coenzyme A, as the thioesters acetoacetyl-CoA and acetyl-CoA. The contractile failure was not observed when glucose, lactate, pyruvate, propionate, valine or isoleucine were present together with acetoacetate, but the addition of acetate or leucine to acetoacetate did not improve performance indicating that improved performance is not mediated through the provision of additional acetyl-CoA. Furthermore, addition of competing substrates that improved function did not relieve the inhibition of 2-oxoglutarate dehydrogenase and actually resulted in the further accumulation of citric acid cycle intermediates "upstream" of 2-oxoglutarate dehydrogenase (2-oxoglutarate, glutamate, citrate and malate). Studies with (1-$\sp{14}$C) pyruvate indicate that the utilization of ketone bodies is associated with activation of NADP$\sp+$dependent malic enzyme and enrichment of the C4 pool of the citric acid cycle. The results suggest that contractile failure induced by ketone bodies in rat heart results from inhibition of 2-oxoglutarate dehydrogenase and that reversal of contractile failure is dissociated from relief of the inhibition, but rather is due to the entry of carbon units into the citric acid cycle as compounds other than acetyl-CoA. This mechanism of enrichment (anaplerosis) provides oxaloacetate for condensation with acetyl-CoA derived from ketone bodies allowing continued energy production by sustaining flux through a span of the citric acid cycle up to the point of inhibition at 2-oxoglutarate dehydrogenase for energy production thereby producing the reducing equivalents necessary to sustain oxidative phosphorylation. ^
Resumo:
Low-flow, low-gradient severe aortic stenosis (AS) is characterised by a small aortic valve area (AVA) and low mean gradient (MG) secondary to a low cardiac output and may occur in patients with either a preserved or reduced left ventricular ejection fraction (LVEF). Symptomatic patients presenting with low-flow, low-gradient severe AS have a dismal prognosis independent of baseline LVEF if managed conservatively and should therefore undergo aortic valve replacement if feasible. Transthoracic echocardiography (TTE) is the first-line investigation for the assessment of AS haemodynamic severity. However, when confronted with guideline-discordant AVA (small) and MG (low) values, there are several reasons other than severe AS combined with a low cardiac output which may lead to such a situation, including erroneous measurements, small body size, inherent inconsistencies in the guidelines' criteria, prolonged ejection time and aortic pseudostenosis. The distinction between these various entities poses a diagnostic challenge. However, it is important to make a distinction because each has very different implications in terms of risk stratification and therapeutic management. In such instances, cardiac catheterisation forms an integral part of the work-up of these patients in order to confirm or refute the echocardiographic findings to guide management decisions appropriately.
Resumo:
For executing the activities of a project, one or several resources are required, which are in general scarce. Many resource-allocation methods assume that the usage of these resources by an activity is constant during execution; in practice, however, the project manager may vary resource usage by individual activities over time within prescribed bounds. This variation gives rise to the project scheduling problem which consists in allocating the scarce resources to the project activities over time such that the project duration is minimized, the total number of resource units allocated equals the prescribed work content of each activity, and precedence and various work-content-related constraints are met.