3,208 research outputs found

    Noise and Quality of Life

    Get PDF
    Noise is defined as an unwanted sound or a combination of sounds that has adverse effects on health. These effects can manifest in the form of physiologic damage or psychological harm through a variety of mechanisms. Chronic noise exposure can cause permanent threshold shifts and loss of hearing in specific frequency ranges. Noise induced hearing loss (NIHL) is thought to be one of the major causes of preventable hearing loss. Approximately 10 million adults and 5.2 million children in the US are already suffering from irreversible noise induced hearing impairment and thirty million more are exposed to dangerous levels of noise each day. The mechanisms of NIHL have yet to be fully identified, but many studies have enhanced our understanding of this process. The role of oxidative stress in NIHL has been extensively studied. There is compelling data to suggest that this damage may be mitigated through the implementation of several strategies including anti-oxidant, anti-ICAM 1 Ab, and anti JNK intervention. The psychological effects of noise are usually not well characterized and often ignored. However, their effect can be equally devastating and may include hypertension, tachycardia, increased cortisol release and increased physiologic stress. Collectively, these effects can have severe adverse consequences on daily living and globally on economic production. This article will review the physiologic and psychologic consequences of noise and its effect on quality of life

    NUMERICAL COMPUTATIONS FOR SELF-CONSISTENT ASTRON E LAYER WITH SLOWING DOWN OF ELECTRONS

    Get PDF
    Components of the program not specifically covered in the preceding report are brought up to date. Elements of the program in which no significant results were produced are mentioned only briefly. Activities are reported under the following headings: Pyrotron Program; High-energy Injection; Astron Program: Livermore Pinch Program; Berkeley Pinch Program; Ion Magnetron: Theoretical Research: Basic Experimental Research; and Engineering and Technological Development. (For preceding period see UCRL-8682.) (W.D.M.

    Tbx5 is Required for Avian and Mammalian Epicardial Formation and Coronary Vasculogenesis.

    Get PDF
    Rationale: Holt-Oram syndrome (HOS) is an autosomal dominant heart-hand syndrome caused by mutations in the TBX5 gene. Overexpression of Tbx5 in the chick proepicardial organ (PEO) impaired coronary blood vessel formation. However, the potential activity of Tbx5 in the epicardium itself, and Tbx5\u27s role in mammalian coronary vasculogenesis, remains largely unknown. Objective: To evaluate the consequences of altered Tbx5 gene dosage during PEO and epicardial development in the embryonic chick and mouse. Methods and Results: Retroviral-mediated knockdown or upregulation of Tbx5 expression in the embryonic chick PEO as well as proepicardial-specific deletion of Tbx5 in the embryonic mouse (Tbx5(epi-/-)) impaired normal PEO cell development, inhibited epicardial and coronary blood vessel formation and altered developmental gene expression. The generation of epicardial-derived cells (EPDCs) and their migration into the myocardium was impaired between embryonic day (E) 13.5-15.5 in mutant hearts due to delayed epicardial attachment to the myocardium and subepicardial accumulation of EPDCs. This caused defective coronary vasculogenesis associated with impaired vascular smooth muscle cell recruitment, and reduced invasion of cardiac fibroblasts and endothelial cells into myocardium. In contrast to wildtype hearts that exhibited an elaborate ventricular vascular network, Tbx5(epi-/-) hearts displayed a marked decrease in vascular density that was associated with myocardial hypoxia as exemplified by HIF1α upregulation and increased binding of Hypoxyprobe-1. Tbx5(epi-/-) mice with such myocardial hypoxia exhibited reduced exercise capacity compared to wildtype mice. Conclusions: Our findings support a conserved Tbx5 dose-dependent requirement for both proepicardial and epicardial progenitor cell development in chick and mouse coronary vascular formation

    Piecewise smooth systems near a co-dimension 2 discontinuity manifold: can one say what should happen?

    Full text link
    We consider a piecewise smooth system in the neighborhood of a co-dimension 2 discontinuity manifold ÎŁ\Sigma. Within the class of Filippov solutions, if ÎŁ\Sigma is attractive, one should expect solution trajectories to slide on ÎŁ\Sigma. It is well known, however, that the classical Filippov convexification methodology is ambiguous on ÎŁ\Sigma. The situation is further complicated by the possibility that, regardless of how sliding on ÎŁ\Sigma is taking place, during sliding motion a trajectory encounters so-called generic first order exit points, where ÎŁ\Sigma ceases to be attractive. In this work, we attempt to understand what behavior one should expect of a solution trajectory near ÎŁ\Sigma when ÎŁ\Sigma is attractive, what to expect when ÎŁ\Sigma ceases to be attractive (at least, at generic exit points), and finally we also contrast and compare the behavior of some regularizations proposed in the literature. Through analysis and experiments we will confirm some known facts, and provide some important insight: (i) when ÎŁ\Sigma is attractive, a solution trajectory indeed does remain near ÎŁ\Sigma, viz. sliding on ÎŁ\Sigma is an appropriate idealization (of course, in general, one cannot predict which sliding vector field should be selected); (ii) when ÎŁ\Sigma loses attractivity (at first order exit conditions), a typical solution trajectory leaves a neighborhood of ÎŁ\Sigma; (iii) there is no obvious way to regularize the system so that the regularized trajectory will remain near ÎŁ\Sigma as long as ÎŁ\Sigma is attractive, and so that it will be leaving (a neighborhood of) ÎŁ\Sigma when ÎŁ\Sigma looses attractivity. We reach the above conclusions by considering exclusively the given piecewise smooth system, without superimposing any assumption on what kind of dynamics near ÎŁ\Sigma (or sliding motion on ÎŁ\Sigma) should have been taking place.Comment: 19 figure

    Global Saturation of Regularization Methods for Inverse Ill-Posed Problems

    Full text link
    In this article the concept of saturation of an arbitrary regularization method is formalized based upon the original idea of saturation for spectral regularization methods introduced by A. Neubauer in 1994. Necessary and sufficient conditions for a regularization method to have global saturation are provided. It is shown that for a method to have global saturation the total error must be optimal in two senses, namely as optimal order of convergence over a certain set which at the same time, must be optimal (in a very precise sense) with respect to the error. Finally, two converse results are proved and the theory is applied to find sufficient conditions which ensure the existence of global saturation for spectral methods with classical qualification of finite positive order and for methods with maximal qualification. Finally, several examples of regularization methods possessing global saturation are shown.Comment: 29 page

    The impact of multiple sclerosis on the identity of mothers in Italy

    Get PDF
    Purpose: This paper reports on one of the themes that emerged from the analysis of the study, regarding the perceived influence of multiple sclerosis (MS) on the identity of mothers in the socio-cultural context of Italy. Method: In-depth interviews were conducted with 16 women at various stages of MS, with follow up interviews with seven of the women. Phenomenology guided the methodology and the analysis was conducted using interpretative phenomenological analysis. Results: Through the research the value of motherhood to the women who participated emerged. The findings illustrated how many strove to maintain controlof their MS, which led to some making comparisons of themselves and other mothers and feeling different. Some women described how they adjusted their roles and found strength in being mothers but others spoke of their feelings of loss. Most women described living in the moment, appreciating the present and living each day as it came. Another significant experience was fear of stigma, both realized in the form of “pity” from others, and the perceived and actual associated stigma for their families. This contributed to why some women were reluctant to disclose their condition. The mothers who took part in this study differed in how they perceived their disabled identity. Conclusion: Although this study was conducted in the socio-cultural setting of Italy, the findings have implications for professionals working with disabled mothers and women with MS in Italy and beyond; including recognizing the value associated with fully identifying oneself as a mother, rather than solely focusing on doingmothering tasks. ‱ Implications for Rehabilitation ‱ Professionals need to be mindful of the value of motherhood for women with multiple sclerosis. ‱ Professionals should support women who feel like they are battling with maintaining control of their multiple sclerosis, who may be adjusting their identity as mothers; recognizing that they may be influenced by the stage of their multiple sclerosis and whether they were diagnosed before or after having their children. ‱ Women can have feelings of loss related to their ability to fully participate in their children’s lives and professionals should work with women to help them identify the value of their mothering role not only in physically participating in activities but also in being emotionally and physically present as a mother

    Generalized Qualification and Qualification Levels for Spectral Regularization Methods

    Get PDF
    The concept of qualification for spectral regularization methods for inverse ill-posed problems is strongly associated to the optimal order of convergence of the regularization error. In this article, the definition of qualification is extended and three different levels are introduced: weak, strong and optimal. It is shown that the weak qualification extends the definition introduced by Mathe and Pereverzev in 2003, mainly in the sense that the functions associated to orders of convergence and source sets need not be the same. It is shown that certain methods possessing infinite classical qualification, e.g. truncated singular value decomposition (TSVD), Landweber's method and Showalter's method, also have generalized qualification leading to an optimal order of convergence of the regularization error. Sufficient conditions for a SRM to have weak qualification are provided and necessary and sufficient conditions for a given order of convergence to be strong or optimal qualification are found. Examples of all three qualification levels are provided and the relationships between them as well as with the classical concept of qualification and the qualification introduced by Mathe and Perevezev are shown. In particular, spectral regularization methods having extended qualification in each one of the three levels and having zero or infinite classical qualification are presented. Finally several implications of this theory in the context of orders of convergence, converse results and maximal source sets for inverse ill-posed problems, are shown.Comment: 20 pages, 1 figur
    • 

    corecore