899 research outputs found
Waste-to-energy application in an industrial district
Industrial districts present some features that can be recognized and exploited in the plant engineering through the proposal of solutions which are not simple applications of models created for individual companies. This work illustrates a waste-to-energy plant to be used for the industrial waste of the district of Friuli Venezia Giulia. The project from the union between university and local entrepreneurs. It is described how the expense for woodworking-waste disposal can turn from a charge into an advantage for the firms of the district thanks to the incineration of this waste in a plant unique for the typology of waste treated. Each plant section is described in detail, underlining innovative approaches and solutions
A graphical approach to relational reasoning
Relational reasoning is concerned with relations over an unspecified domain of discourse. Two limitations to which it is customarily subject are: only dyadic relations are taken into account; all formulas are equations, having the same expressive power as first-order sentences in three variables. The relational formalism inherits from the Peirce-Schröder tradition, through contributions of Tarski and many others.
Algebraic manipulation of relational expressions (equations in particular) is much less natural than developing inferences in first-order logic; it may in fact appear to be overly machine-oriented for direct hand-based exploitation.
The situation radically changes when one resorts to a convenient representation of relations based on labeled graphs. The paper provides details of this representation, which abstracts w.r.t. inessential features of expressions.
Formal techniques illustrating three uses of the graph representation of relations are discussed: one technique deals with translating first-order specifications into the calculus of relations; another one, with inferring equalities within this calculus with the aid of convenient diagram-rewriting rules; a third one with checking, in the specialized framework of set theory, the definability of particular set operations. Examples of use of these techniques are produced; moreover, a promising approach to mechanization of graphical relational reasoning is outlined
A chemotactic model for interaction of antagonistic microflora colonies: front asymptotics and numerical simulations
This paper studies a two-dimensional chemotactic model for two species in
which one of them produces a chemo-repellent for the other. It is shown
asymptotically and numerically how the chemical inhibits the invasion of a
moving front for the second species and how stable steady states, which depend
on the chemical concentration, can be reached. The results qualitatively
explain experimental observations by Swain and Ray (Microbiol. Res. 164(2),
2009), where colonies of bacteria produce metabolite agents which prevent the
invasion of fungi.Comment: New updated version: 24.04.2012. Substitutes previous version of
25.10.2011. New references added. Note a change in titl
Screening for cardiovascular disease risk factors beginning in childhood
Cardiovascular diseases (CVD) are the leading cause of death worldwide. Individual detection and intervention on CVD risk factors and behaviors throughout childhood and adolescence has been advocated as a strategy to reduce CVD risk in adulthood. The U.S. National Heart, Lung, and Blood Institute (NHLBI) has recently recommended universal screening of several risk factors in children and adolescents, at odds with several recommendations of the U.S. Services Task Force and of the U.K. National Screening committee. In the current review, we discuss the goals of screening for CVD risk factors (elevated blood pressure, abnormal blood lipids, diabetes) and behaviors (smoking) in children and appraise critically various screening recommendations. Our review suggests that there is no compelling evidence to recommend universal screening for elevated blood pressure, abnormal blood lipids, abnormal blood glucose, or smoking in children and adolescents. Targeted screening of these risk factors could be useful but specific screening strategies have to be evaluated. Research is needed to identify target populations, screening frequency, intervention, and follow-up. Meanwhile, efforts should rather focus on the primordial prevention of CVD risk factors and at maintaining a lifelong ideal cardiovascular health through environmental, policy, and educational approaches
Screening for cardiovascular disease risk factors beginning in childhood
Cardiovascular diseases (CVD) are the leading cause of death worldwide. Individual detection and intervention on CVD risk factors and behaviors throughout childhood and adolescence has been advocated as a strategy to reduce CVD risk in adulthood. The U.S. National Heart, Lung, and Blood Institute (NHLBI) has recently recommended universal screening of several risk factors in children and adolescents, at odds with several recommendations of the U.S. Services Task Force and of the U.K. National Screening committee. In the current review, we discuss the goals of screening for CVD risk factors (elevated blood pressure, abnormal blood lipids, diabetes) and behaviors (smoking) in children and appraise critically various screening recommendations. Our review suggests that there is no compelling evidence to recommend universal screening for elevated blood pressure, abnormal blood lipids, abnormal blood glucose, or smoking in children and adolescents. Targeted screening of these risk factors could be useful but specific screening strategies have to be evaluated. Research is needed to identify target populations, screening frequency, intervention, and follow-up. Meanwhile, efforts should rather focus on the primordial prevention of CVD risk factors and at maintaining a lifelong ideal cardiovascular health through environmental, policy, and educational approaches
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