204 research outputs found

    On the Complexity of Anchored Rectangle Packing

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    I feel bad and look worse than you: Social comparisons moderate the effect of mood on face health judgement

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    Mood can bias the judgements people make about themselves and how people compare themselves to others. However, it is not yet clear whether mood also affects appearance-based self-evaluations and social comparisons. Given the importance of perceived health status for well-being, we investigated the effect of mood on self-image and social comparisons of healthiness during two versions of a face health judgement task. Thirty participants judged how they felt compared to healthy and unhealthy looking versions of their own (self version) and a stranger’s face (stranger version), after a positive, negative and neutral mood induction. The effect of mood was dependent on self/stranger task order. Although mood did not affect face health judgement for participants who initially judged themselves against their own face, it did affect face health judgement for participants who initially judged themselves in comparison to a stranger’s face. After the positive and negative mood inductions, these participants judged themselves as equivalent to healthier/unhealthier looking versions of their own and stranger’s faces, respectively. Thus, social comparisons of facial healthiness could provide a perceptual measure of state well-being

    Vegetative propagation of the red alga Rhodochorton purpureum by means of fragments that escape digestion by herbivores

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    Intertidal populations of the filamentous red alga Rhodochorton purpureujn (Lightf.) Rosenv. (Nemaliales, Acrochaetiaceae) in the Northern Netherlands grow as dense velvety turfs in the understory of large fucalean algae. The small and rather constant size of the turf (1 to 1.5 mm) and the high percentage of 'decapitated' filaments suggest that the turf is continually 'shorn' by herbivores. Two grazing invertebrates were found on the turf: the gastropod Littorina littorea (L.) and the amphipod Gamrnarus salinus Spooner Differences between the 2 grazers in the size of ingested R. purpureum fragments and in the proportion of ingested fragments with intact apices were attributed to differences in their feeding mechanisms. Both species egested live R. purpureum fragments In their faecal pellets. These fragments had the capacity to regenerate into new filaments when cultured in the laboratory. In the field small tufts of R. purpureurn filaments were found on bare substratum, originating from fragments contained in sticky, detritus-rich envelopes, probably faecal pellets. Experiments in unlalgal cultures showed that the regeneratlve capacity of fragments is very high, as it proceeds over d broad range of temperature and light conditions, even in total darkness We conclude that the capacity of R. purpureum fragments to escape digestion by herbivores probably plays an important role in vegetative propagation of the species

    Organ-specific responses during brain death:increased aerobic metabolism in the liver and anaerobic metabolism with decreased perfusion in the kidneys

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    Hepatic and renal energy status prior to transplantation correlates with graft survival. However, effects of brain death (BD) on organ-specific energy status are largely unknown. We studied metabolism, perfusion, oxygen consumption, and mitochondrial function in the liver and kidneys following BD. BD was induced in mechanically-ventilated rats, inflating an epidurally-placed Fogarty-catheter, with sham-operated rats as controls. A 9.4T-preclinical MRI system measured hourly oxygen availability (BOLD-related R2*) and perfusion (T1-weighted). After 4 hrs, tissue was collected, mitochondria isolated and assessed with high-resolution respirometry. Quantitative proteomics, qPCR, and biochemistry was performed on stored tissue/plasma. Following BD, the liver increased glycolytic gene expression (Pfk-1) with decreased glycogen stores, while the kidneys increased anaerobic- (Ldha) and decreased gluconeogenic-related gene expression (Pck-1). Hepatic oxygen consumption increased, while renal perfusion decreased. ATP levels dropped in both organs while mitochondrial respiration and complex I/ATP synthase activity were unaffected. In conclusion, the liver responds to increased metabolic demands during BD, enhancing aerobic metabolism with functional mitochondria. The kidneys shift towards anaerobic energy production while renal perfusion decreases. Our findings highlight the need for an organ-specific approach to assess and optimise graft quality prior to transplantation, to optimise hepatic metabolic conditions and improve renal perfusion while supporting cellular detoxification

    Online Search for a Hyperplane in High-Dimensional Euclidean Space

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    We consider the online search problem in which a server starting at the origin of a dd-dimensional Euclidean space has to find an arbitrary hyperplane. The best-possible competitive ratio and the length of the shortest curve from which each point on the dd-dimensional unit sphere can be seen are within a constant factor of each other. We show that this length is in Ω(d)O(d3/2)\Omega(d)\cap O(d^{3/2})

    Paging with Succinct Predictions

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    Paging is a prototypical problem in the area of online algorithms. It hasalso played a central role in the development of learning-augmented algorithms-- a recent line of research that aims to ameliorate the shortcomings ofclassical worst-case analysis by giving algorithms access to predictions. Suchpredictions can typically be generated using a machine learning approach, butthey are inherently imperfect. Previous work on learning-augmented paging hasinvestigated predictions on (i) when the current page will be requested again(reoccurrence predictions), (ii) the current state of the cache in an optimalalgorithm (state predictions), (iii) all requests until the current page getsrequested again, and (iv) the relative order in which pages are requested. We study learning-augmented paging from the new perspective of requiring theleast possible amount of predicted information. More specifically, thepredictions obtained alongside each page request are limited to one bit only.We consider two natural such setups: (i) discard predictions, in which thepredicted bit denotes whether or not it is ``safe'' to evict this page, and(ii) phase predictions, where the bit denotes whether the current page will berequested in the next phase (for an appropriate partitioning of the input intophases). We develop algorithms for each of the two setups that satisfy allthree desirable properties of learning-augmented algorithms -- that is, theyare consistent, robust and smooth -- despite being limited to a one-bitprediction per request. We also present lower bounds establishing that ouralgorithms are essentially best possible.<br

    Indampen van dunne mestfracties in combinatie met een luchtwasser

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    The effect of an evaporator/air-scrubber combination on the reduction of ammonia and odour was evaluated and the evaporation capacity was assessed. It was concluded that at pig farms substantial reduction (one third) of the slurry volume can cost effectively be achieved while maintaining ammonia and odour reduction effiency

    Feeling Bad and Looking Worse: Negative Affect Is Associated with Reduced Perceptions of Face-Healthiness

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    Some people perceive themselves to look more, or less attractive than they are in reality. We investigated the role of emotions in enhancement and derogation effects; specifically, whether the propensity to experience positive and negative emotions affects how healthy we perceive our own face to look and how we judge ourselves against others. A psychophysical method was used to measure healthiness of self-image and social comparisons of healthiness. Participants who self-reported high positive (N = 20) or negative affectivity (N = 20) judged themselves against healthy (red-tinged) and unhealthy looking (green-tinged) versions of their own and stranger’s faces. An adaptive staircase procedure was used to measure perceptual thresholds. Participants high in positive affectivity were un-biased in their face health judgement. Participants high in negative affectivity on the other hand, judged themselves as equivalent to less healthy looking versions of their own face and a stranger’s face. Affective traits modulated self-image and social comparisons of healthiness. Face health judgement was also related to physical symptom perception and self-esteem; high physical symptom reports were associated a less healthy self-image and high self-reported (but not implicit) self-esteem was associated with more favourable social comparisons of healthiness. Subject to further validation, our novel face health judgement task could have utility as a perceptual measure of well-being. We are currently investigating whether face health judgement is sensitive to laboratory manipulations of mood

    Responsiveness differences in outcome instruments after revision hip arthroplasty: What are the implications?

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    Responsiveness to change is an important psychometric property of an outcome instrument. Assessment of health-related quality of life (HRQoL) is critical to outcome assessment after total joint replacement, a surgery aimed at improving pain, function and HRQoL of the patients undergoing these procedures. In a recent study, Shi et al. examined the responsiveness to change of various subscales of two instruments, physician-administered Harris Hip Score and patient self-administered Short Form-36 (SF-36), 6 months after revision total hip arthroplasty. The responsiveness statistics for both scales were reasonable, higher for Harris Hip Score than SF-36. This is the first study to examine responsiveness of these instruments in revision THA patients in a systematic fashion
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