137 research outputs found

    Depth, Highness and DNR Degrees

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    A sequence is Bennett deep [5] if every recursive approximation of the Kolmogorov complexity of its initial segments from above satisfies that the difference between the approximation and the actual value of the Kolmogorov complexity of the initial segments dominates every constant function. We study for different lower bounds r of this difference between approximation and actual value of the initial segment complexity, which properties the corresponding r(n)-deep sets have. We prove that for r(n) = Δn, depth coincides with highness on the Turing degrees. For smaller choices of r, i.e., r is any recursive order function, we show that depth implies either highness or diagonally-non-recursiveness (DNR). In particular, for left-r.e. sets, order depth already implies highness. As a corollary, we obtain that weakly-useful sets are either high or DNR. We prove that not all deep sets are high by constructing a low order-deep set. Bennett's depth is defined using prefix-free Kolmogorov complexity. We show that if one replaces prefix-free by plain Kolmogorov complexity in Bennett's depth definition, one obtains a notion which no longer satisfies the slow growth law (which stipulates that no shallow set truth-table computes a deep set); however, under this notion, random sets are not deep (at the unbounded recursive order magnitude). We improve Bennett's result that recursive sets are shallow by proving all K-trivial sets are shallow; our result is close to optimal. For Bennett's depth, the magnitude of compression improvement has to be achieved almost everywhere on the set. Bennett observed that relaxing to infinitely often is meaningless because every recursive set is infinitely often deep. We propose an alternative infinitely often depth notion that doesn't suffer this limitation (called i.o. depth).We show that every hyperimmune degree contains a i.o. deep set of magnitude Δn, and construct a π01- class where every member is an i.o. deep set of magnitude Δn. We prove that every non-recursive, non-DNR hyperimmune-free set is i.o. deep of constant magnitude, and that every nonrecursive many-one degree contains such a set

    Investigating hyper-vigilance for social threat of lonely children

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    The hypothesis that lonely children show hypervigilance for social threat was examined in a series of three studies that employed different methods including advanced eye-tracking technology. Hypervigilance for social threat was operationalized as hostility to ambiguously motivated social exclusion in a variation of the hostile attribution paradigm (Study 1), scores on the Children’s Rejection-Sensitivity Questionnaire (Study 2), and visual attention to socially rejecting stimuli (Study 3). The participants were 185 children (11 years-7 months to 12 years-6 months), 248 children (9 years-4 months to 11 years-8 months) and 140 children (8 years-10 months to 12 years-10 months) in the three studies, respectively. Regression analyses showed that, with depressive symptoms covaried, there were quadratic relations between loneliness and these different measures of hypervigilance to social threat. As hypothesized, only children in the upper range of loneliness demonstrated elevated hostility to ambiguously motivated social exclusion, higher scores on the rejection sensitivity questionnaire, and disengagement difficulties when viewing socially rejecting stimuli. We found that very lonely children are hypersensitive to social threat

    Domestic cats (Felis silvestris catus) do not show signs of secure attachment to their owners

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    The Ainsworth Strange Situation Test (SST) has been widely used to demonstrate that the bond between both children and dogs to their primary carer typically meets the requirements of a secure attachment (i.e. the carer being perceived as a focus of safety and security in otherwise threatening environments), and has been adapted for cats with a similar claim made. However methodological problems in this latter research make the claim that the cat-owner bond is typically a secure attachment, operationally definable by its behaviour in the SST, questionable. We therefore developed an adapted version of the SST with the necessary methodological controls which include a full counterbalance of the procedure. A cross-over design experiment with 20 cat-owner pairs (10 each undertaking one of the two versions of the SST first) and continuous focal sampling was used to record the duration of a range of behavioural states expressed by the cats that might be useful for assessing secure attachment. Since data were not normally distributed, non-parametric analyses were used on those behaviours shown to be reliable across the two versions of the test (which excluded much cat behaviour). Although cats vocalised more when the owner rather the stranger left the cat with the other individual, there was no other evidence consistent with the interpretation of the bond between a cat and its owner meeting the requirements of a secure attachment. These results are consistent with the view that adult cats are typically quite autonomous, even in their social relationships, and not necessarily dependent on others to provide a sense of security and safety. It is concluded that alternative methods need to be developed to characterise the normal psychological features of the cat-owner bond

    Review of methods used by chiropractors to determine the site for applying manipulation

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    Background: With the development of increasing evidence for the use of manipulation in the management of musculoskeletal conditions, there is growing interest in identifying the appropriate indications for care. Recently, attempts have been made to develop clinical prediction rules, however the validity of these clinical prediction rules remains unclear and their impact on care delivery has yet to be established. The current study was designed to evaluate the literature on the validity and reliability of the more common methods used by doctors of chiropractic to inform the choice of the site at which to apply spinal manipulation. Methods: Structured searches were conducted in Medline, PubMed, CINAHL and ICL, supported by hand searches of archives, to identify studies of the diagnostic reliability and validity of common methods used to identify the site of treatment application. To be included, studies were to present original data from studies of human subjects and be designed to address the region or location of care delivery. Only English language manuscripts from peer-reviewed journals were included. The quality of evidence was ranked using QUADAS for validity and QAREL for reliability, as appropriate. Data were extracted and synthesized, and were evaluated in terms of strength of evidence and the degree to which the evidence was favourable for clinical use of the method under investigation. Results: A total of 2594 titles were screened from which 201 articles met all inclusion criteria. The spectrum of manuscript quality was quite broad, as was the degree to which the evidence favoured clinical application of the diagnostic methods reviewed. The most convincing favourable evidence was for methods which confirmed or provoked pain at a specific spinal segmental level or region. There was also high quality evidence supporting the use, with limitations, of static and motion palpation, and measures of leg length inequality. Evidence of mixed quality supported the use, with limitations, of postural evaluation. The evidence was unclear on the applicability of measures of stiffness and the use of spinal x-rays. The evidence was of mixed quality, but unfavourable for the use of manual muscle testing, skin conductance, surface electromyography and skin temperature measurement. Conclusions: A considerable range of methods is in use for determining where in the spine to administer spinal manipulation. The currently published evidence falls across a spectrum ranging from strongly favourable to strongly unfavourable in regard to using these methods. In general, the stronger and more favourable evidence is for those procedures which take a direct measure of the presumptive site of care– methods involving pain provocation upon palpation or localized tissue examination. Procedures which involve some indirect assessment for identifying the manipulable lesion of the spine–such as skin conductance or thermography–tend not to be supported by the available evidence.https://doi.org/10.1186/2045-709X-21-3

    Myocardial ischemia and reperfusion: The role of oxygen radicals in tissue injury

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    Thrombolytic therapy has gained widespread acceplance as a means of treating coronary artery thrombosis in patients with acute myocardial infarction. Although experimental data have demonstrated that timely reperfusion limits the extent of infarction caused by regional ischemia, there is growing evidence that reperfusion is associated with an inflammatory response to ischemia that exacerbates the tissue injury. Ischemic myocardium releases archidonate and complement-derived chemotactic factors, e.g., leukotriene B 4 and C 5a , which attract and activate neutrophils. Reperfusion of ischemic myocardium accelerates the influx of neutrophils, which release reactive oxygen products, such as superoxide anion and hydrogen peroxide, resulting in the formation of a hydroxyl radical and hypochlorous acid. The latter two species may damage viable endothelial cells and myocytes via the peroxidation of lipids and oxidation of protein sulfhydryl groups, leading to perturbations of membrane permeability and enzyme function. Neutrophil depletion by antiserum and inhibition of neutrophil function by drugs, e.g., ibuprofen, prostaglandins (prostacyclin and PGE 1 ), or a monoclonal antibody, to the adherence-promoting glycoprotein Mo-1 receptor, have been shown to limit the extent of canine myocardial injury due to coronary artery occlusion/reperfusion. Recent studies have challenged the hypothesis that xanthine-oxidase-derived oxygen radicals are a cause of reperfusion injury. Treatment with allopurinol or oxypurinol may exert beneficial effects on ischemic myocardium that are unrelated to the inhibition of xanthine oxidase. Furthermore, the human heart may lack xanthine oxidase activity. Further basic research is needed, therefore, to clarify the importance of xanthine oxidase in the pathophysiology of reperfusion injury. Current data are highly suggestive of a deleterious role of the neutrophil in organ reperfusion and justify consideration of the clinical investigation of neutrophil inhibitors in patients receiving thrombolytic agents during the evolution of an acute myocardial infarction.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44595/1/10557_2004_Article_BF00133206.pd

    Housing: An Under-Explored Influence on Children’s Well-Being and Becoming

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    Research on housing has tended to focus on adult outcomes, establishing relationships between housing and a number of aspects of health and well-being. Research exploring the influence of housing on children has been more limited, and has tended to focus on adult concerns around risk behaviours, behavioural problems and educational attainment. While these outcomes are important, they neglect the impact of housing on children’s lives beyond these concerns. There are a number of reasons to believe that housing would play an important role in children’s well-being more broadly. Family stress and strain models highlight how housing difficulties experienced by adults may have knock on effects for children, while Bronfenbrenner’s ecological approach to human development emphasises the importance of children’s experiences of their environments, of which the home is among the most important. This paper summaries the existing evidence around housing and child outcomes, predominantly educational and behavioural outcomes, and argues for the extension of this work to consider the impact of housing on children’s lives more broadly, especially their subjective well-being
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