960 resultados para Compactive effort
Resumo:
This article reviews the empirical and theoretical bases for recommendations regarding lifting technique. Lifting from postures involving extreme lumbar vertebral flexion, (approximately 60degrees of lumbar flexion, characterised by absence of electromyographical activity in erector spinae) has the potential to contribute to damage to ligaments and intervertebral discs, especially if combined with lateral flexion or rotation. The only appropriate recommendation regarding posture of the lumbar spine during lifting is to avoid postures involving extreme lumbar vertebral flexion (and rotation and lateral flexion). There is no empirical basis for avoiding postures involving moderate lumbar vertebral flexion, and no justification for advocating lifting from a full squat posture. Further, lifting from semi-squat postures, involving a moderate range of flexion at both knees and trunk, allows a pattern of interjoint coordination which appears to be functional in reducing muscular effort. Lifting training is generally ineffective, and there is unlikely to be a single best technique which is appropriate in all situations. Consequently, it may be preferable to provide education in general lifting guidelines and assist lifters to discover individually appropriate postures and patterns of movement. The article concludes by presenting recommendations for lifting technique which are justified by current knowledge.
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As inorganic arsenic is a proven human carcinogen, significant effort has been made in recent decades in an attempt to understand arsenic carcinogenesis using animal models, including rodents (rats and mice) and larger mammals such as beagles and monkeys. Transgenic animals were also used to test the carcinogenic effect of arsenicals, but until recently all models had failed to mimic satisfactorily the actual mechanism of arsenic carcinogenicity. However, within the past decade successful animal models have been developed using the most common strains of mice or rats. Thus dimethylarsinic acid (DMA), an organic arsenic compound which is the major metabolite of inorganic arsenicals in mammals, has been proven to be tumorigenic in such animals. Reports of successful cancer induction in animals by inorganic arsenic (arsenite and arsenate) have been rare, and most carcinogenetic studies have used organic arsenicals such as DMA combined with other tumor initiators. Although such experiments used high concentrations. of arsenicals for the promotion of tumors, animal models using doses of arsenicals species closed to the exposure level of humans in endemic areas are obviously the most significant. Almost all researchers have used drinking water or food as the pathway for the development of animal model test systems in order to mimic chronic arsenic poisoning in humans; such pathways seem more likely to achieve desirable results. (C) 2002 Elsevier Science Ireland Ltd. All rights reserved.
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Yield strength (YS) ageing curves have been modelled for A356 and A357 aluminium casting alloys below the solvus temperature of the main hardening precipitate. Predictions are based on the Shercliff and Ashby methodology (Acta MetaH. Mater. 38 (1990) 1789) for wrought alloys. Differences between strengthening in wrought and cast Al-Si-Mg alloys are considered. A Brinell hardness to YS conversion incorporating strain hardening has been established to enable YS ageing curves to be predicted with reduced experimental effort. (C) 2002 Elsevier Science B.V. All rights reserved.
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A glasshouse study was undertaken to determine if the zeolite mineral clinoptilolite from an Australian deposit in combination with rock phosphate (RP) could significantly enhance the uptake of P by sunflowers. The zeolite/RP combination was intended to act as an exchange-fertiliser, with Ca2+ exchanging onto the zeolite in response to plant uptake of nutrient cations (NH4+ or K) enhancing the dissolution of the RP. A reactive RP (Sechura) and a relatively non-reactive RP (Duchess) were examined. Zeolite was used in Ca2+-, K+- and NH4+-saturated forms at ratios of 3.5:1 and 7:1 with RP; Ca2+-zeolite was considered the control, with exchange-induced dissolution possible from K+-and NH4+-zeolite, The zeolite/RP mixture was applied as a vertical band adjacent to the sunflower seedling. In addition, N was supplied as urea in an effort to determine if RP dissolution resulted from H+ release by nitrification. Phosphorus supply from the zeolite/RP system was compared with an available P source (KH2PO4). The experiment clearly demonstrated greatly enhanced plant uptake of P from RP when applied in combination with NH4-zeolite, though the P uptake was lower than that from the soluble P source. The zeolite/RP interaction was much more effective with the reactive R-P than the non-reactive material, Within the NH4+-zeolite/RP band, root proliferation was greatly increased, as would be expected in an exchange-fertiliser system. The K+-zeolite system did not produce a significantly greater yield than the Ca2+-zeolite control, probably because adequate K+ supply from the basal application reduced uptake within the zeolite/RP band, thus reducing the extent of exchange-induced dissolution. Nevertheless, increased root proliferation within the band was observed, implying that exchange-induced dissolution may also be possible from this system. The zeolite/RP system offers the considerable advantage of P release in response to plant demand and is unique in this regard. (C) 2002 Elsevier Science B.V. All rights reserved.
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Only a small proportion of the mouse genome is transcribed into mature messenger RNA transcripts. There is an international collaborative effort to identify all full-length mRNA transcripts from the mouse, and to ensure that each is represented in a physical collection of clones. Here we report the manual annotation of 60,770 full-length mouse complementary DNA sequences. These are clustered into 33,409 'transcriptional units', contributing 90.1% of a newly established mouse transcriptome database. Of these transcriptional units, 4,258 are new protein-coding and 11,665 are new non-coding messages, indicating that non-coding RNA is a major component of the transcriptome. 41% of all transcriptional units showed evidence of alternative splicing. In protein-coding transcripts, 79% of splice variations altered the protein product. Whole-transcriptome analyses resulted in the identification of 2,431 sense-antisense pairs. The present work, completely supported by physical clones, provides the most comprehensive survey of a mammalian transcriptome so far, and is a valuable resource for functional genomics.
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Cestodes (tapeworms) are a derived, parasitic clade of the phylum Platyhelminthes (flatworms). The cestode body wall represents an adaptation to its endoparasitic lifestyle. The epidermis forms a nonciliated syncytium, and both muscular and nervous system are reduced. Morphological differences between cestodes and free-living flatworms become apparent already during early embryogenesis. Cestodes have a complex life cycle that begins with an infectious larva, called the oncosphere. In regard to cell number, cestode oncospheres are among the simplest multicellular organisms, containing in the order of 50-100 cells. As part of our continuing effort to analyze embryonic development in flatworms, we describe here the staining pattern obtained with acTub in embryos and larvae of the cestode Hymenolepis diminuta and, briefly, the monogenean Neoheterocotyle rhinobatidis. In addition, we labeled the embryonic musculature of Hymenolepis with phalloidin. In Hymenolepis embryos, two different cell types that we interpret as neurons and epidermal gland cells express acTub. There exist only two neurons that develop close to the midline at the anterior pole of the embryo. The axons of these two neurons project posteriorly into the center of the oncosphere, where they innervate the complex of muscles that is attached to the booklets. In addition to neurons, acTub labels a small and invariant set of epidermal gland cells that develop at superficial positions, anteriorly adjacent to the neurons, in the dorsal midline, and around the posteriorly located hooklets. During late stages of embryogenesis they spread and form a complete covering of the embryo. We discuss these data in the broader context of platyhelminth embryology.
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This article presents a fairness theory-based conceptual framework for studying and managing consumers’ emotions during service recovery attempts. The conceptual framework highlights the central role played by counterfactual thinking and accountability. Findings from five focus groups are also presented to lend further support to the conceptual framework. Essentially, the article argues that a service failure event triggers an emotional response in the consumer, and from here the consumer commences an assessment of the situation, considering procedural justice, interactional justice, and distributive justice elements, while engaging in counterfactual thinking and apportioning accountability. More specifically, the customer assesses whether the service provider could and should have done something more to remedy the problem and how the customer would have felt had these actions been taken. The authors argue that during this process situational effort is taken into account when assessing accountability. When service providers do not appear to exhibit an appropriate level of effort, consumers attribute this to the service provider not caring. This in turn leads to the customer feeling more negative emotions, such as anger and frustration. Managerial implications of the study are discussed.
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Male and female consumers place different emphasis on elements of the service recovery process. Perceptions were influenced by gender of the service provider and by a match of customer and service provider gender. The study, an experimental design with 712 respondents, found that when service providers, irrespective of gender, display concern and give customers voice and a sizable compensation, both men and women reported more positive attitudes compared with when this was not so. Combinations of high voice with high outcome and high voice with high concern were especially important in positively influencing perceptions of effort, regardless of gender. However, the authors also found that there were significant differences between male and female respondents regarding their perceptions of how service recovery should be handled. Women want their views heard during service recovery attempts and to be allowed to provide input. Men, in contrast, do not view voice as important.
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Marine reserves have been widely touted as a promising strategy for managing fisheries and protecting marine biodiversity. However, their establishment can involve substantial social conflict and may not produce the anticipated biological and economic benefits. A crucial factor associated with the success of marine reserves for enhancing fisheries and protecting biodiversity is the spatial distribution of fishing activity. Fishers may be attracted to the perimeter of a reserve in expectation of spillover of adult fishes. This concentration of effort can reduce spillover of fish to the surrounding fishery and has major implications for the effectiveness of reserves in achieving ecological and socioeconomic goals. We examined the spatial distribution of fishing activity relative to California's Big Creek Marine Ecological Reserve and found no aggregation near the reserve. We discuss the factors driving the spatial distribution of fishing activity relative to the reserve and the relevance of that distribution to the performance and evaluation of marine reserves.
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For products sold with warranty, the warranty servicing cost can be reduced by improving product reliability through a development process. However, this increases the unit manufacturing cost. Optimal development must achieve a trade-off between these two costs. The outcome of the development process is uncertain and needs to be taken into account in the determination of the optimal development effort. The paper develops a model where this uncertainty is taken into account. (C) 2003 Elsevier Ltd. All rights reserved.
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Like those in other sectors, managers in community-based organisations face an uncertain and challenging future. Research and writing about the community sector (non-government, notjor-profit, or third seclOr) has canvassed a wide range of issues. A selective review of the recent literature reveals the breadth of research interest in the challenges facing community sector managers. While some reflection on the implications for managers of current economic and social policy contexts is crucial for this sector, research effort needs to be focused on understanding how third sector managers construe their current strategic challenges and the strategies they use to address them A small sample ofmanagers working in a regional area in South East Queensland was asked to identify current strategic concerns related to the future viability of their organisations. The key issues raised by managers are compared with the issues raised in the research literature. Results -to date indicate that managers' concerns are reflected in the research literature, but that managers are also concemed about the current trends in social policy towards collaboration, amalgamation, and pannership. Implications of these findings for managers operating in this sector are discussed.
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Posteroanterior stiffness of the lumbar spine is influenced by factors, including trunk muscle activity and intra-abdominal pressure (IAP). Because these factors vary with breathing, this study investigated whether stiffness is modulated in a cyclical manner with respiration. A further aim was to investigate the relationship between stiffness and IAP or abdominal and paraspinal muscle activity. Stiffness was measured from force-displacement responses of a posteroanterior force applied over the spinous process of L-2 and L-4. Recordings were made of IAP and electromyographic activity from L-4/L-2 erector spinae, abdominal muscles, and chest wall. Stiffness was measured with the lung volume held at the extremes of tidal volume and at greater and lesser volumes. Stiffness at L-4 and L-2 increased above base-level values at functional residual capacity (L-2 14.9 N/mm and L-4 15.3 N/mm) with both inspiratory and expiratory efforts. The increase was related to the respiratory effort and was greatest during maximum expiration (L-2 24.9 N/mm and L-4 23.9 N/mm). The results indicate that changes in trunk muscle activity and IAP with respiratory efforts modulate spinal stiffness. In addition, the diaphragm may augment spinal stiffness via attachment of its crural fibers to the lumbar vertebrae.
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As a result of the local autonomy program that commenced in Indonesia in Jan 2001, there is a concern regarding the applicability of the formalized model of security & the possibility of that being replaced by a local community-based security model. This rather informal security model is then promoted to be the only form of security used between societies & the nation. However, this model does not solve the problem because of widespread corruption, collusion, & nepotism, & the many limitations of the Indonesian National Police (Polri), a police department that has a mediocre & generalized level of service. In relation to autonomy, the effort of empowering the police units from the regional police down will bridge the gap between the people's ability to protect themselves & the limitations of those that are sworn to uphold the law. 17 References. Adapted from the source document.
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Theory supports the use of a segmental methodology (SM) for bioimpedance analysis (BIA) of body water (BW). However, previous studies have generally failed to show a significant improvement when the SM is used in place of a whole-body methodology. A pilot study was conducted to compare the two methodologies in control and overweight subjects. BW of each subject was measured by D2O dilution and also estimated from BIA measurements. Bland and Altman analysis was used to compare the two values of BW. The SM resulted in a small but not significantly improved limits of agreement of measured and BIA estimated BW (psimilar to0.3). This and the results of previous studies suggest that improvements in prediction of BW obtained from application of the SM may be intrinsically small and may not justify the additional effort in application.
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A id??ia que anima este artigo ?? a de juntar argumentos que demonstrem a import??ncia de se reformar as rela????es do Estado com a sociedade para que a reforma do aparelho do Estado tenha sucesso. S??o discutidas as vantagens e desvantagens da provis??o dos servi??os p??blicos sociais por meio de organiza????es p??blicas n??o-estatais, como uma estrat??gia para superar a crise de governan??a do Estado contempor??neo e tamb??m como um caminho para reduzir a precariedade dos servi??os sociais. O esfor??o de supera????o da crise do Estado vem se traduzindo na redefini????o do modo de financiamento e da maneira de organizar a execu????o das pol??ticas p??blicas sociais, de forma a garantir efetividade na resposta ??s demandas sociais e maior efici??ncia na produ????o dos servi??os. A desestatiza????o da provis??o dos servi??os sociais coloca as sociedades democr??ticas diante do desafio de resolver como manter a responsabilidade do Estado frente ao interesse p??blico. Trata-se de responder como transitar do estatal para o p??blico, garantindo que a provis??o de servi??os p??blicos n??o dependa exclusivamente do Estado, sem que este abandone seu papel de financiador e regulador das atividades de interesse geral. O que n??o merece mais d??vidas ?? que a constitui????o de uma esfera p??blica que venha a atuar em simetria com o Estado e o mercado, como uma poss??vel solu????o duradoura e democr??tica para a produ????o de bens e servi??os sociais, atrav??s de organiza????es p??blicas n??o-estatais, passe a ser considerada como uma das principais tarefas te??ricas e pr??ticas que desafiam os atores sociais envolvidos com as quest??es da gest??o p??blica.