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Theoretical Grounds (theoretical + ground)
Selected AbstractsLiberating Anger, Embodying Knowledge: A Comparative Study of María Lugones and Zen Master HakuinHYPATIA, Issue 2 2010JEN MCWEENYArticle first published online: 9 DEC 200 This paper strengthens the theoretical ground of feminist analyses of anger by explaining how the angers of the oppressed are ways of knowing. Relying on insights created through the juxtaposition of Latina feminism and Zen Buddhism, I argue that these angers are special kinds of embodied perceptions that surface when there is a profound lack of fit between a particular bodily orientation and its framing world of sense. As openings to alternative sensibilities, these angers are transformative, liberatory, and deeply epistemological. [source] Domestic rivalry and export performance: theory and evidence from international airline marketsCANADIAN JOURNAL OF ECONOMICS, Issue 2 2009Joseph A. Clougherty Abstract The much studied relationship between domestic rivalry and export performance consists of those supporting a national-champion rationale, and those supporting a rivalry rationale. While the empirical literature generally supports the positive effects of domestic rivalry, the national-champion rationale actually rests on firmer theoretical ground. We address this inconsistency by providing a theoretical framework that illustrates three paths via which domestic rivalry translates into enhanced international exports. Furthermore, empirical tests on the world airline industry elicit the existence of one particular path , an enhanced firm performance effect , that connects domestic rivalry with improved international exports. La relation fort étudiée entre rivalité domestique et performance à l'exportation interpelle ceux qui défendent l'idée de supporter un champion national et ceux qui supporte l'idée de rivalité. Alors que la littérature spécialisée supporte généralement les effets positifs de la rivalité domestique, l'idée de support pour un champion national repose sur des fondements théoriques plus solides. On propose un cadre d'analyse théorique qui illustre trois voies par lesquelles la rivalité domestique se traduit en exportations internationales accrues. Des tests empiriques dans l'industrie mondiale du transport aérien soulignent l'existence d'une voie particulière , un effet de performance améliorée de l'entreprise , qui connecte la rivalité domestique et l'amélioration des exportations vers l'étranger. [source] NO COMMUNITY IS AN ISLAND: THE EFFECTS OF RESOURCE DEPRIVATION ON URBAN VIOLENCE IN SPATIALLY AND SOCIALLY PROXIMATE COMMUNITIES,CRIMINOLOGY, Issue 3 2006DANIEL P. MEARS The link between resource deprivation and urban violence has long been explored in criminological research. Studies, however, have largely ignored the potential for resource deprivation in particular communities to affect rates of violence in others. The relative inattention is notable because of the strong theoretical grounds to anticipate influences that extend both to geographically contiguous areas and to those that, though not contiguous, share similar social characteristics. We argue that such influences,what we term spatial and social proximity effects, respectively,constitute a central feature of community dynamics. To support this argument, we develop and test theoretically derived hypotheses about spatial and social proximity effects of resource deprivation on aggregated and disaggregated homicide counts. Our analyses indicate that local area resource deprivation contributes to violence in socially proximate communities, an effect that, in the case of instrumental homicides, is stronger when such communities are spatially proximate. We conclude by discussing the implications of our findings for theories focused on community-level social processes and violence, and for policies aimed at reducing crime in disadvantaged areas. [source] THE CRIME-CONTROL EFFECT OF INCARCERATION: DOES SCALE MATTER?,CRIMINOLOGY AND PUBLIC POLICY, Issue 2 2006RAYMOND V. LIEDKA Research Summary: Several prominent empirical studies estimate models of a constant proportional effect of prison on crime, finding that effect is substantial and negative. A separate literature argues against the crime-reducing effect of prison but mainly on theoretical grounds. This second literature suggests that the elasticity of the prison/crime relationship is not constant. We provide a model that nests these two literatures. Using data from the United States over 30 years, we find strong evidence that the negative relationship between prison and crime becomes less strongly negative as the scale of imprisonment increases. This revisionist model indicates that (1) at low levels of incarceration, a constant elasticity model underestimates the negative relationship between incarceration and crime, and (2) at higher levels of incarceration, the constant elasticity model overstates the negative effect. Policy Implications: These results go beyond the claim of declining marginal returns, instead finding accelerating declining marginal returns. As the prison population continues to increase, albeit at a slower rate, after three decades of phenomenal growth, these findings provide an important caution that for many jurisdictions, the point of accelerating declining marginal returns may have set in. Any policy discussion of the appropriate scale of punishment should be concerned with the empirical impact of this expensive and intrusive government intervention. [source] Use of resampling to select among alternative error structure specifications for GLMM analyses of repeated measurements,INTERNATIONAL JOURNAL OF METHODS IN PSYCHIATRIC RESEARCH, Issue 1 2004Scott Tonidandel Abstract Autocorrelated error and missing data due to dropouts have fostered interest in the flexible general linear mixed model (GLMM) procedures for analysis of data from controlled clinical trials. The user of these adaptable statistical tools must, however, choose among alternative structural models to represent the correlated repeated measurements. The fit of the error structure model specification is important for validity of tests for differences in patterns of treatment effects across time, particularly when maximum likelihood procedures are relied upon. Results can be affected significantly by the error specification that is selected, so a principled basis for selecting the specification is important. As no theoretical grounds are usually available to guide this decision, empirical criteria have been developed that focus on model fit. The current report proposes alternative empirical criteria that focus on bootstrap estimates of actual type I error and power of tests for treatment effects. Results for model selection before and after the blind is broken are compared. Goodness-of-fit statistics also compare favourably for models fitted to the blinded or unblinded data, although the correspondence to actual type I error and power depends on the particular fit statistic that is considered. Copyright © 2004 Whurr Publishers Ltd. [source] Theory of chemical bonds in metalloenzymes.INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 15 2010Abstract Reaction mechanisms of oxygen evolution in native and artificial photosynthesis II (PSII) systems have been investigated on the theoretical grounds, together with experimental results. First of all, our previous broken-symmetry (BS) molecular orbitals (MO) calculations are reviewed to elucidate the instability of the d,-p, bond in high-valent (HV) Mn(X)O systems and the d,-p,-d, bond in HV MnOMn systems. The triplet instability of these bonds entails strong or intermediate diradical characters: ,Mn(IV)O, and ,MnOMn,; the BS MO resulted from strong electron correlation, leading to the concept of electron localizations and local spins. The BS computations have furthermore revealed guiding principles for derivation of selection rules for radical reactions of local spins. As a continuation of these theoretical results, the BS MO interaction diagrams for oxygen-radical coupling reactions in the oxygen evolution complex (OEC) in the PSII have been depicted to reveal scope and applicability of local singlet diradical (LSD) and local triplet diradical (LTD) mechanisms that have been successfully utilized for theoretical understanding of oxygenation reactions mechanisms by p450 and methane monooxygenase (MMO). The manganese-oxide cluster models examined are London, Berlin, and Berkeley models of CaMn4O4 and related clusters Mn4O4 and Mn3Ca. The BS MO interaction diagrams have revealed the LSD and/or LTD mechanisms for generation of molecular oxygen in the total low-, intermediate and high-spin states of these clusters. The spin alignments are found directly corresponding to the spin-coupling mechanisms of oxygen-radical sites in these clusters. The BS UB3LYP calculations of the clusters have been performed to confirm the comprehensive guiding principles for oxygen evolution; charge and spin densities by BS UB3LYP are utilized for elucidation and confirmation of the LSD and LTD mechanisms. Applicability of the proposed selection rules are examined in comparison with a lot of accumulated experimental and theoretical results for oxygen evolution reactions in native and artificial PSII systems. © 2010 Wiley Periodicals, Inc. Int J Quantum Chem, 2010 [source] Wrongful trading and the liability of company directors: a theoretical perspective,LEGAL STUDIES, Issue 3 2005Andrew Keay When a company enters insolvent liquidation, the liquidator might take proceedings, under s 214 of the Insolvency Act 1986, against one or more of the company's directors on the basis that the director(s) engaged in wrongful trading. If found liable, a director might be ordered by a court to contribute to the assets of the company. This article examines whether subjecting directors to liability f or wrongful trading is theoretically justifiable. After briefly explaining the origin, aims, rationale and operation of s 214, the article then rehearses and evaluates the arguments propounded by several scholars against any justijkation for a provision in the mould of s 214. Next the article investigates some of the reasons given for supporting the provision. Following this some consideration is given to whether it is possible to opt out of s 214, and, if not, whether this should be permitted. It is concluded, inter alia, that while s 214 is not representative of good regulation, some form of prohibition against wrongful trading can be justified on theoretical grounds. [source] Sense of coherence as a protective factor for demoralisation in women with a recent diagnosis of gynaecological cancerPSYCHO-ONCOLOGY, Issue 3 2007Nadia Boscaglia Abstract Background: Demoralisation is a dysphoric mood state commonly seen in the medically ill. Its core features comprise hopelessness, helplessness, loss of purpose and meaning, despair, and existential distress. Sense of Coherence (SOC) is a quantifiable dispositional orientation that captures the character traits likely to protect against demoralisation. In this study, we hypothesised on theoretical grounds that a strong SOC would be associated with lower levels of demoralisation in the context of gynaecological cancer (GC). Method: One hundred and twenty women with a recent (<12 months) diagnosis of GC were recruited from outpatient clinics. Participants were interviewed and completed questionnaire measures of demoralisation and SOC. A multiple regression analysis was performed using the five subscales of the Demoralisation Scale as predictor variables and SOC as the dependent variable. Results: Together, the five subscales of the Demoralisation Scale accounted for 60% of the variance in SOC. Conclusions: The results supported the hypothesis, suggesting that SOC may be protective against demoralisation in the context of serious illness. Larger, multivariate studies that examine additional variables (such as coping) would be required to further clarify the relationship between SOC and demoralisation. In the meantime, clinicians may want to consider efforts to enhance SOC in patients. Copyright © 2006 John Wiley & Sons, Ltd. [source] Heterogeneous expectations of traders in speculative futures marketsTHE JOURNAL OF FUTURES MARKETS, Issue 5 2001Darren L. Frechette Assistant Professor The representative agent hypothesis is disputable on theoretical grounds because it is inconsistent with observed trading behavior and the existence of speculative markets. In such markets, the representative agent hypothesis implies agents hold homogeneous expectations. If this were true, speculative markets would fail as only one side of the market would be represented, either demand or supply. Nonetheless, the homogeneity assumption has been maintained in the past to ensure tractability because of the difficulty of explicit aggregation across heterogeneous expectations. In this article, we present and apply an approach for analyzing heterogeneity in specific market settings. To do so, our approach specifies an underlying distribution of expectations that is consistent with heterogeneity across expectations. To demonstrate the utility of the approach, we present results from its application to a time series of commodity futures prices. Results are consistent with the conclusion that significant heterogeneity in expectations exists in speculative futures markets. © 2001 John Wiley & Sons, Inc. Jrl Fut Mark 21:429,446, 2001 [source] Evolution and modulation of intracellular calcium release during long-lasting, depleting depolarization in mouse muscleTHE JOURNAL OF PHYSIOLOGY, Issue 19 2008Leandro Royer Intracellular calcium signals regulate multiple cellular functions. They depend on release of Ca2+ from cellular stores into the cytosol, a process that in many types of cells appears to be tightly controlled by changes in [Ca2+] within the store. In contrast with cardiac muscle, where depletion of Ca2+ in the sarcoplasmic reticulum is a crucial determinant of termination of Ca2+ release, in skeletal muscle there is no agreement regarding the sign, or even the existence of an effect of SR Ca2+ level on Ca2+ release. To address this issue we measured Ca2+ transients in mouse flexor digitorum brevis (FDB) skeletal muscle fibres under voltage clamp, using confocal microscopy and the Ca2+ monitor rhod-2. The evolution of Ca2+ release flux was quantified during long-lasting depolarizations that reduced severely the Ca2+ content of the SR. As in all previous determinations in mammals and non-mammals, release flux consisted of an early peak, relaxing to a lower level from which it continued to decay more slowly. Decay of flux in this second stage, which has been attributed largely to depletion of SR Ca2+, was studied in detail. A simple depletion mechanism without change in release permeability predicts an exponential decay with time. In contrast, flux decreased non-exponentially, to a finite, measurable level that could be maintained for the longest pulses applied (1.8 s). An algorithm on the flux record allowed us to define a quantitative index, the normalized flux rate of change (NFRC), which was shown to be proportional to the ratio of release permeability P and inversely proportional to Ca2+ buffering power B of the SR, thus quantifying the ,evacuability' or ability of the SR to empty its content. When P and B were constant, flux then decayed exponentially, and NFRC was equal to the exponential rate constant. Instead, in most cases NFRC increased during the pulse, from a minimum reached immediately after the early peak in flux, to a time between 200 and 250 ms, when the index was no longer defined. NFRC increased by 111% on average (in 27 images from 18 cells), reaching 300% in some cases. The increase may reflect an increase in P, a decrease in B, or both. On experimental and theoretical grounds, both changes are to be expected upon SR depletion. A variable evacuability helps maintain a constant Ca2+ output under conditions of diminishing store Ca2+ load. [source] Reconstruction of an atmospheric tracer source using the principle of maximum entropy.THE QUARTERLY JOURNAL OF THE ROYAL METEOROLOGICAL SOCIETY, Issue 610 2005I: Theory Abstract Over recent years, tracing back sources of chemical species dispersed through the atmosphere has been of considerable importance, with an emphasis on increasing the precision of the source resolution. This need stems from many problems: being able to estimate the emissions of pollutants; spotting the source of radionuclides; evaluating diffuse gas fluxes; etc. We study the high-resolution retrieval on a continental scale of the source of a passive atmospheric tracer, given a set of concentration measurements. In the first of this two-part paper, we lay out and develop theoretical grounds for the reconstruction. Our approach is based on the principle of maximum entropy on the mean. It offers a general framework in which the information input prior to the inversion is used in a flexible and controlled way. The inversion is shown to be equivalent to the minimization of an optimal cost function, expressed in the dual space of observations. Examples of such cost functions are given for different priors of interest to the retrieval of an atmospheric tracer. In this respect, variational assimilation (4D-Var), as well as projection techniques, are obtained as biproducts of the method. The framework is enlarged to incorporate noisy data in the inversion scheme. Part II of this paper is devoted to the application and testing of these methods. Copyright © 2005 Royal Meteorological Society [source] Male infertility, female fertility and extrapair copulationsBIOLOGICAL REVIEWS, Issue 2 2009Oren Hasson ABSTRACT Females that are socially bonded to a single male, either in a social monogamy or in a social polygyny, are often sexually polyandrous. Extrapair copulations (EPC) have often been suggested or rejected, on both empirical and theoretical grounds, as an important mechanism that enables females to avoid fertility risks in case their socially bonded male is infertile. Here, we explore this possibility in two steps. First, we present a mathematical model that assumes that females have no precopulatory information about male fertility, and shows that a female EPC strategy increases female reproductive success only if certain specific conditions are upheld in the nature of male infertility. In particular, these conditions require both (i) that fertile sperm precedence (FSP) is absent or incomplete within ejaculates of the same male (i.e. that an infertile male is, at least partly, truly infertile), and (ii) the existence of FSP among ejaculates of different males (such that infertile spermatozoa of the infertile male are at a disadvantage when competing against spermatozoa of a fertile male). Second, to evaluate their potential role in the evolution of female EPC, we review the abundance and FSP patterns of the different male infertility types. The conclusion is drawn that some common infertility types, such as poor sperm count or motility, contribute to the evolution of female EPC, whereas other common infertility types, such as sperm depletion or allocation in a social monogamy (but not in a social polygyny), and in particular male driven polyspermy, do not. Also, a deeper look at the arms race between sperm fertilization efficiency and female barriers to sperm may answer the non-trivial question: "why are some types of infertility so common?" [source] Is ACCTRAN better than DELTRAN?CLADISTICS, Issue 6 2008Ingi Agnarsson When parsimony ancestral character reconstruction is ambiguous, it is often resolved in favour of the more complex character state. Hence, secondary loss (secondary "absence") of a complex feature is favoured over parallel gains of that feature as this preserves the stronger hypothesis of homology. We believe that such asymmetry in character state complexity is important information for understanding character evolution in general. However, we here point out an inappropriate link that is commonly made between this approach and the accelerated transformation (ACCTRAN) algorithm. In ACCTRAN, changes are assigned along branches of a phylogenetic tree as close to the root as possible. This has been taken to imply that ACCTRAN will minimize hypotheses of parallel origins of complex traits and thus that ACCTRAN is philosophically better justified than the alternatives, such as delayed transformation (DELTRAN), where changes are assigned along branches as close to the tips as possible. We provide simple examples to show that such views are mistaken and that neither ACCTRAN nor DELTRAN consistently minimize parallel gain of complex traits. We therefore do not see theoretical grounds for favouring the popular ACCTRAN algorithm. © The Willi Hennig Society 2008. [source] Phylogeny and Speciation of FelidsCLADISTICS, Issue 2 2000Michelle Y. Mattern The phylogeny of the Felidae is reconstructed using a total evidence approach combining sequences from 12S rRNA, 16S rRNA, NADH-5, and cytochrome b genes with morphological and karyological characters. The 1504-character data set generated two equally parsimonious trees (CI = 0.413, 1795 steps) of which a strict consensus revealed one polytomy in the placement of the bay cat group. The tree supports several traditional groupings such as the genera Panthera and Lynx and the ocelot group of small South American felids, and it provides additional resolution of relationships within and among the major felid lineages. Combining phylogenetic, distributional, and ecological data indicates that vicariant speciation has played a relatively minor role in the diversification of the felids (approximately 26% of events), while sympatric speciation has been more important than expected on theoretical grounds (approximately 51.8% of events), although postspeciation dispersal may have blurred the boundaries between sympatric, parapatric, and peripheral isolate modes. An examination of ecological changes on the felid tree shows repeated patterns of resource partitioning in time (activity patterns), space (preferred habitat type), and food (as measured by body size) among closely related species. The rapid diversification of the cats thus appears to have been associated more with ecological than with geological separation. [source] | |||||||||||||||||||