9,648 research outputs found

    Regional differences and sources of organochlorine pesticides in soils surrounding chemical industrial parks

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    Concentrations of organochlorine pesticides (OCPs; dichlorodiphenyltrichloroethanes (DDTs), hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB)) were investigated in 105 soil samples collected in vicinity of the chemical industrial parks in Tianjin, China. OCP concentrations significantly varied in the study area, high HCH and DDT levels were found close to the chemical industrial parks. The intensity of agricultural activity and distance from the potential OCP emitters have important influences on the OCP residue distributions. Principal component analysis indicates that HCH pollution is a mix of historical technical HCH and current lindane pollution and DDT pollution input is only due to technical DDT sources. The significant correlations of OCP compounds reveal that HCHs, DDTs and HCB could have some similar sources of origin

    The poetry as reliable evidence of linguistic phenomena

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    Many linguists refuse to believe that poetic and especially metrical - texts can provide reliable evidence of linguistic phenomena. In this article, I show that the Medieval Greek poetry represents an exception. By means of a case-study I demonstrate that the metre of the does not constitute a straitjacket for the language, but actually presents a flexible system: a comparison of the distribution of the object clitic pronouns (OCP) in the two parallel manuscripts in which the 14th century Chronicle of Morea has been preserved not only confirms the established rules for OCP distribution but also reveals that the allows many rephrasing possibilities on all levels of grammar (phonology, morphology, lexicon and syntax)

    Organochlorine pesticides exposure & preterm birth

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    Commento su invito ad uno studio su esposizione fetale a composti organoclorurat

    Branching-time model checking of one-counter processes

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    One-counter processes (OCPs) are pushdown processes which operate only on a unary stack alphabet. We study the computational complexity of model checking computation tree logic (CTL) over OCPs. A PSPACE upper bound is inherited from the modal mu-calculus for this problem. First, we analyze the periodic behaviour of CTL over OCPs and derive a model checking algorithm whose running time is exponential only in the number of control locations and a syntactic notion of the formula that we call leftward until depth. Thus, model checking fixed OCPs against CTL formulas with a fixed leftward until depth is in P. This generalizes a result of the first author, Mayr, and To for the expression complexity of CTL's fragment EF. Second, we prove that already over some fixed OCP, CTL model checking is PSPACE-hard. Third, we show that there already exists a fixed CTL formula for which model checking of OCPs is PSPACE-hard. To obtain the latter result, we employ two results from complexity theory: (i) Converting a natural number in Chinese remainder presentation into binary presentation is in logspace-uniform NC^1 and (ii) PSPACE is AC^0-serializable. We demonstrate that our approach can be used to obtain further results. We show that model-checking CTL's fragment EF over OCPs is hard for P^NP, thus establishing a matching lower bound and answering an open question of the first author, Mayr, and To. We moreover show that the following problem is hard for PSPACE: Given a one-counter Markov decision process, a set of target states with counter value zero each, and an initial state, to decide whether the probability that the initial state will eventually reach one of the target states is arbitrarily close to 1. This improves a previously known lower bound for every level of the Boolean hierarchy by Brazdil et al

    Family Planning Market in India

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    This literature review captures existing knowledge across a range of products and players in India's family planning market. The product scope covers condoms, oral contraceptive pills, injectable contraceptives, intra-uterine devices, and male and female sterilization.The broad reach of this analysis brings diverse perspectives together to provide a complete picture of the current state of the market. The review can be particularly useful for field practitioners, donors, and other players looking to understand the current state of discovery in the India family planning market

    Reduced Order Optimal Control of the Convective FitzHugh-Nagumo Equation

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    In this paper, we compare three model order reduction methods: the proper orthogonal decomposition (POD), discrete empirical interpolation method (DEIM) and dynamic mode decomposition (DMD) for the optimal control of the convective FitzHugh-Nagumo (FHN) equations. The convective FHN equations consists of the semi-linear activator and the linear inhibitor equations, modeling blood coagulation in moving excitable media. The semilinear activator equation leads to a non-convex optimal control problem (OCP). The most commonly used method in reduced optimal control is POD. We use DEIM and DMD to approximate efficiently the nonlinear terms in reduced order models. We compare the accuracy and computational times of three reduced-order optimal control solutions with the full order discontinuous Galerkin finite element solution of the convection dominated FHN equations with terminal controls. Numerical results show that POD is the most accurate whereas POD-DMD is the fastest
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