2,157 research outputs found

    Orientation cues for high-flying nocturnal insect migrants: do turbulence-induced temperature and velocity fluctuations indicate the mean wind flow?

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    Migratory insects flying at high altitude at night often show a degree of common alignment, sometimes with quite small angular dispersions around the mean. The observed orientation directions are often close to the downwind direction and this would seemingly be adaptive in that large insects could add their self-propelled speed to the wind speed, thus maximising their displacement in a given time. There are increasing indications that high-altitude orientation may be maintained by some intrinsic property of the wind rather than by visual perception of relative ground movement. Therefore, we first examined whether migrating insects could deduce the mean wind direction from the turbulent fluctuations in temperature. Within the atmospheric boundary-layer, temperature records show characteristic ramp-cliff structures, and insects flying downwind would move through these ramps whilst those flying crosswind would not. However, analysis of vertical-looking radar data on the common orientations of nocturnally migrating insects in the UK produced no evidence that the migrants actually use temperature ramps as orientation cues. This suggests that insects rely on turbulent velocity and acceleration cues, and refocuses attention on how these can be detected, especially as small-scale turbulence is usually held to be directionally invariant (isotropic). In the second part of the paper we present a theoretical analysis and simulations showing that velocity fluctuations and accelerations felt by an insect are predicted to be anisotropic even when the small-scale turbulence (measured at a fixed point or along the trajectory of a fluid-particle) is isotropic. Our results thus provide further evidence that insects do indeed use turbulent velocity and acceleration cues as indicators of the mean wind direction

    Morphine-induced hallucinations - resolution with switching to oxycodone: a case report and review of the literature

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    Palliation of pain with morphine in cancer patients can be complicated by adverse effects. Tolerance to these effects such as nausea and drowsiness usually occurs within a few days allowing continuation of morphine therapy. However, some patients may develop intolerable adverse effects even after several months on morphine when the dose is increased. A case of morphine-induced hallucinations in a cancer patient who had been on a subcutaneous infusion of diamorphine for several months is discussed. A switch to oxycodone resolved his hallucinations and gave him a new lease of life. The theories behind and evidence for opioid-switching is discussed along with strategies for dealing with intolerable opioid-induced adverse effects

    The inevitable youthfulness of known high-redshift radio galaxies

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    Radio galaxies can be seen out to very high redshifts, where in principle they can serve as probes of the early evolution of the Universe. Here we show that for any model of radio-galaxy evolution in which the luminosity decreases with time after an initial rapid increase (that is, essentially all reasonable models), all observable high-redshift radio-galaxies must be seen when the lobes are less than 10^7 years old. This means that high-redshift radio galaxies can be used as a high-time-resolution probe of evolution in the early Universe. Moreover, this result helps to explain many observed trends of radio-galaxy properties with redshift [(i) the `alignment effect' of optical emission along radio-jet axes, (ii) the increased distortion in radio structure, (iii) the decrease in physical sizes, (iv) the increase in radio depolarisation, and (v) the increase in dust emission] without needing to invoke explanations based on cosmology or strong evolution of the surrounding intergalactic medium with cosmic time, thereby avoiding conflict with current theories of structure formation.Comment: To appear in Nature. 4 pages, 2 colour figures available on request. Also available at http://www-astro.physics.ox.ac.uk/~km

    Gene expression and matrix turnover in overused and damaged tendons

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    Chronic, painful conditions affecting tendons, frequently known as tendinopathy, are very common types of sporting injury. The tendon extracellular matrix is substantially altered in tendinopathy, and these changes are thought to precede and underlie the clinical condition. The tendon cell response to repeated minor injuries or “overuse” is thought to be a major factor in the development of tendinopathy. Changes in matrix turnover may also be effected by the cellular response to physical load, altering the balance of matrix turnover and changing the structure and composition of the tendon. Matrix turnover is relatively high in tendons exposed to high mechanical demands, such as the supraspinatus and Achilles, and this is thought to represent either a repair or tissue maintenance function. Metalloproteinases are a large family of enzymes capable of degrading all of the tendon matrix components, and these are thought to play a major role in the degradation of matrix during development, adaptation and repair. It is proposed that some metalloproteinase enzymes are required for the health of the tendon, and others may be damaging, leading to degeneration of the tissue. Further research is required to investigate how these enzyme activities are regulated in tendon and altered in tendinopathy. A profile of all the metalloproteinases expressed and active in healthy and degenerate tendon is required and may lead to the development of new drug therapies for these common and debilitating sports injuries

    Differences between children and adolescents in treatment response to atomoxetine and the correlation between health-related quality of life and Attention Deficit/Hyperactivity Disorder core symptoms: Meta-analysis of five atomoxetine trials

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    <p>Abstract</p> <p>Objectives</p> <p>To explore the influence of age on treatment responses to atomoxetine and to assess the relationship between core symptoms of attention deficit/hyperactivity disorder (ADHD) and health-related quality of life (HR-QoL) outcomes.</p> <p>Data Sources</p> <p>Data from five similar clinical trials of atomoxetine in the treatment of children and adolescents with ADHD were included in this meta-analysis.</p> <p>Study Selection</p> <p>Atomoxetine studies that used the ADHD Rating Scale (ADHD-RS) and the Child Health and Illness Profile Child Edition (CHIP-CE) as outcome measures were selected.</p> <p>Interventions</p> <p>Treatment with atomoxetine.</p> <p>Main Outcome Measures</p> <p>Treatment group differences (atomoxetine vs placebo) in terms of total score, domains, and subdomains of the CHIP-CE were compared across age groups, and correlations between ADHD-RS scores and CHIP-CE scores were calculated by age.</p> <p>Results</p> <p>Data of 794 subjects (611 children, 183 adolescents) were pooled. At baseline, adolescents showed significantly (p < 0.05) greater impairment compared with children in the Family Involvement, Satisfaction with Self, and Academic Performance subdomains of the CHIP-CE. Treatment effect of atomoxetine was significant in both age groups for the Risk Avoidance domain and its subdomains. There was a significant age-treatment interaction with greater efficacy seen in adolescents in both the Risk Avoidance domain and the Threats to Achievement subdomain. Correlations between ADHD-RS and CHIP-CE scores were generally low at baseline and moderate in change from baseline and were overall similar in adolescents and children.</p> <p>Conclusions</p> <p>Atomoxetine was effective in improving some aspects of HR-QoL in both age groups. Correlations between core symptoms of ADHD and HR-QoL were low to moderate.</p

    Tendinopathy—from basic science to treatment

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    Chronic tendon pathology (tendinopathy), although common, is difficult to treat. Tendons possess a highly organized fibrillar matrix, consisting of type I collagen and various 'minor' collagens, proteoglycans and glycoproteins. The tendon matrix is maintained by the resident tenocytes, and there is evidence of a continuous process of matrix remodeling, although the rate of turnover varies at different sites. A change in remodeling activity is associated with the onset of tendinopathy. Major molecular changes include increased expression of type III collagen, fibronectin, tenascin C, aggrecan and biglycan. These changes are consistent with repair, but they might also be an adaptive response to changes in mechanical loading. Repeated minor strain is thought to be the major precipitating factor in tendinopathy, although further work is required to determine whether it is mechanical overstimulation or understimulation that leads to the change in tenocyte activity. Metalloproteinase enzymes have an important role in the tendon matrix, being responsible for the degradation of collagen and proteoglycan in both healthy patients and those with disease. Metalloproteinases that show increased expression in painful tendinopathy include ADAM (a disintegrin and metalloproteinase)-12 and MMP (matrix metalloproteinase)-23. The role of these enzymes in tendon pathology is unknown, and further work is required to identify novel and specific molecular targets for therapy

    Psychometric properties of the quality of life scale Child Health and Illness Profile-Child Edition in a combined analysis of five atomoxetine trials

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    Our aim was to evaluate the psychometric properties of the generic quality of life (QoL) scale Child Health and Illness Profile-Child Edition (CHIP-CE) by means of a combined analysis of atomoxetine clinical trials in children and adolescents with attention-deficit/hyperactivity disorder (ADHD). Individual patient-level data from five clinical trials were included in the combined analysis. Psychometric properties of the CHIP-CE were explored in terms of internal consistency and structure. Patients (n = 794) aged between 6 and 15 years (mean 9.7) with mean baseline ADHD Rating Scale of 41.8 ± 8.04 were included. On average, 0.7 (SD 2.23) items were missing for the whole CHIP-CE. The internal consistency of the CHIP-CE assessed by Cronbach’s alpha was good for all sub-domains at baseline and at endpoint. Considerable ceiling effects were only observed for the “restricted activity” sub-domain. No considerable floor effects were seen. The factor analysis supported the 12-factor solution for the sub-domains, but not the 5-factor solution for the domains. Our analyses were based on a large sample of non-US patients which allowed the measurement of clear changes in QoL over time. The results support that the CHIP-CE scale is psychometrically robust over time in terms of internal consistency and structure

    Negotiating daughterhood and strangerhood: retrospective accounts of serial migration

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    Most considerations of daughtering and mothering take for granted that the subjectivities of mothers and daughters are negotiated in contexts of physical proximity throughout daughters’ childhoods. Yet many mothers and daughters spend periods separated from each other, sometimes across national borders. Globally, an increasing number of children experience life in transnational families. This paper examines the retrospective narratives of four women who were serial migrants as children (whose parents migrated before they did) . It focuses on their accounts of the reunion with their mothers and how these fit with the ways in which they construct their mother-daughter relationships. We take a psychosocial approach by using a psychoanalytically-informed reading of these narratives to acknowledge the complexities of the attachments produced in the context of migration and to attend to the multi-layered psychodynamics of the resulting relationships. The paper argues that serial migration positioned many of the daughters in a conflictual emotional landscape from which they had to negotiate ‘strangerhood’ in the context of sadness at leaving people to whom they were attached in order to join their mothers (or parents). As a result, many were resistant to being positioned as daughters, doing daughtering and being mothered in their new homes
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