5,422 research outputs found

    Adaptive latitudinal variation in Common Blackbird Turdus merula nest characteristics

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    Nest construction is taxonomically widespread, yet our understanding of adaptive intraspecific variation in nest design remains poor. Nest characteristics are expected to vary adaptively in response to predictable variation in spring temperatures over large spatial scales, yet such variation in nest design remains largely overlooked, particularly amongst open-cup-nesting birds. Here, we systematically examined the effects of latitudinal variation in spring temperatures and precipitation on the morphology, volume, composition, and insulatory properties of open-cup-nesting Common Blackbirds’ Turdus merula nests to test the hypothesis that birds living in cooler environments at more northerly latitudes would build better insulated nests than conspecifics living in warmer environments at more southerly latitudes. As spring temperatures increased with decreasing latitude, the external diameter of nests decreased. However, as nest wall thickness also decreased, there was no variation in the diameter of the internal nest cups. Only the mass of dry grasses within nests decreased with warmer temperatures at lower latitudes. The insulatory properties of nests declined with warmer temperatures at lower latitudes and nests containing greater amounts of dry grasses had higher insulatory properties. The insulatory properties of nests decreased with warmer temperatures at lower latitudes, via changes in morphology (wall thickness) and composition (dry grasses). Meanwhile, spring precipitation did not vary with latitude, and none of the nest characteristics varied with spring precipitation. This suggests that Common Blackbirds nesting at higher latitudes were building nests with thicker walls in order to counteract the cooler temperatures. We have provided evidence that the nest construction behavior of open-cup-nesting birds systematically varies in response to large-scale spatial variation in spring temperatures

    Cognitive-Behavioral Therapy with Youth

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    Cognitive-behavioral therapies (CBTs) with children and adolescents use enactive, performance-based procedures, as well as cognitive interventions to produce changes in thinking, feeling, and behavior. Various forms of CBT have a common goal to help the child develop a constructive worldview and a problem-solving attitude. The problem-solving orientation can also be referred to as a coping template. Through the provision of carefully planned experiences, CBT helps the child and family build an adaptive, problem-solving perspective

    Complexity reduction and policy consensus: asylum seekers, the right to work, and the ‘pull factor’ thesis in the UK context

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    Since the early 2000s, asylum policy in Western states has become increasingly dominated by the concept of the ‘pull factor’—the idea that the economic rights afforded to asylum seekers can act as a migratory pull, and will have a bearing on the numbers of asylum applications received. The pull factor thesis has been widely discredited by researchers but remains powerful among policymakers. Through an analysis of the pull factor in the UK context, and drawing on insights from Cultural Political Economy, this article argues that the hegemony of the pull factor thesis is best understood as a ‘policy imaginary’ which has become sedimented through both discursive and extra-discursive practices and processes. The article offers a means of understanding how a common sense assumption—which is challenged by a large body of evidence—has come to dominate policymaking in a key area of concern for politicians and policymakers

    Middle Convolution and Harnad Duality

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    We interpret the additive middle convolution operation in terms of the Harnad duality, and as an application, generalize the operation to have a multi-parameter and act on irregular singular systems.Comment: 50 pages; v2: Submitted version once revised according to referees' comment

    'Reclaiming the criminal' : the role and training of prison officers in England, 1877-1914

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    This article examines the role and training of prison officers in England, between 1877 and 1914. It is concerned with the changing penal philosophies and practices of this period and how these were implemented in local prisons, and the duties of the prison officer. More broadly, this article argues that the role of the prison officer and their training (from 1896) reflect wider ambiguities in prison policy and practice during this period

    MicroShunt versus trabeculectomy for surgical management of glaucoma: a retrospective analysis

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    This case-control study aims to compare the efficacy, safety, and postoperative burden of MicroShunt versus trabeculectomy. The first consecutive cohort of MicroShunt procedures (n = 101) was matched to recent historical trabeculectomy procedures (n = 101) at two London hospital trusts. Primary endpoints included changes in intraocular pressure (IOP) and glaucoma medications. Secondary outcome measures included changes in retinal nerve fibre layer (RNFL) thickness, rates of complications, further theatre interventions, and the number of postoperative visits. From the baseline to Month-18, the median [interquartile range] IOP decreased from 22 [17–29] mmHg (on 4 [3–4] medications) to 15 [10–17] mmHg (on 0 [0–2] medications) and from 20 [16–28] mmHg (on 4 [3–4] medications) to 11 [10–13] mmHg (on 0 [0–0] medications) in the MicroShunt and trabeculectomy groups, respectively. IOP from Month-3 was significantly higher in the MicroShunt group (p = 0.006), with an increased number of medications from Month-12 (p = 0.024). There were greater RNFL thicknesses from Month-6 in the MicroShunt group (p = 0.005). The rates of complications were similar (p = 0.060) but with fewer interventions (p = 0.031) and postoperative visits (p = 0.001) in the MicroShunt group. Therefore, MicroShunt has inferior efficacy to trabeculectomy in lowering IOP and medications but provides a better safety profile and postoperative burden and may delay RNFL loss

    Effects of COVID-19 pandemic on glaucoma appointment scheduling in a tertiary hospital in London, UK

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    PURPOSE: To investigate the impact of the delay in patient appointments caused by the COVID-19 pandemic and the triage system on the glaucomatous disease of patients in a London tertiary hospita METHODS: Observational retrospective study that randomly selected 200 glaucoma patients with more than 3 months of unintended delay for their post-COVID visit and other inclusion and exclusion criteria. Demographic information, clinical data, number of drugs, best-corrected visual acuity (BCVA), intraocular pressure (IOP), visual field (VF) mean deviation (MD), and global peripapillary retinal nerve fibre layer (pRNFL) thickness were obtained from the pre- and post-COVID visit. At the post-COVID visit, the clinical outcomes subjective clinical concern and change of treatment or need for surgery were also annotated. The variables were stratified by glaucoma severity (according to the MD into early, moderate and advanced) and by delay time (more and less than 12 months) and analysed using SPSS. RESULTS: We included 121 eyes (from 71 patients). The median patient age was 74 years (interquartile range -IQR- 15), 54% were males and 52% Caucasians. Different glaucoma types and all glaucoma severities were included. When data was stratified for glaucoma severity, at the pre-COVID visit, significant differences in BCVA, CCT and IOP were observed and there were significantly higher values in the early glaucoma group. The median follow-up delay was 11 months (IQR 8), did not differ between the glaucoma severity groups and did not correlate to the glaucoma severity. At the post-COVID visit, significant differences in BCVA, IOP, and Global pRNFL thickness were observed between the glaucoma severity groups, as lower BCVA and higher IOP and pRNFL thickness were observed in the early glaucoma group. At the post-COVID visit there was cause for concern in 40 eyes: 5 were followed more closely, 22 had a change of treatment and 13 were booked for surgery (3 for cataract and 10 for glaucoma surgery). However, the number of eyes with causes for concern were similar between the glaucoma severity groups and there was no correlation between these clinical outcomes and the delay of the post-COVID visit. The number of topical hypotensive medications increased significantly after the post-COVID visit, higher number of medications were observed in the advanced glaucoma group. When differences of IOP, MD and pRNFL thickness between the pre and post-COVID visit, only the MD difference was significantly different between the glaucoma severity groups because it was higher in the severe group. When data was stratified for delay longer or shorter than 12 months, no differences were observed between the groups except at the pre-COVID visit, when the numbers of patients with MD deviation >−6 dB had longer delay time. When differences in IOP, MD and RNFL thickness were calculated, only the pRNFL thickness showed significant differences between the delay groups, because it was higher in the longer delay group. Finally, when paired analysis of the variables at the pre- and post-COVID visits, stratified by glaucoma severity and delay were conducted, although there were no significant differences in IOP in any group, the BCVA decreased significantly in the overall group and in the longer delay groups, the number of hypotensive drugs increased significantly overall and in the moderate and advanced glaucoma, the MD of the VF worsened significantly in the overall group and in the early glaucoma and longer delay groups and the pRNFL thickness decreased significantly in all groups. CONCLUSIONS: We document that delayed care impacts negatively on the glaucomatous disease of our patients because at the post-COVID visit there were reasons for clinical concern in a third of eyes that resulted in change of treatment or surgery. However, these clinical consequences were not related to IOP, glaucoma severity or delay time and reflect that the triage methods implemented worked adequately. The most sensitive parameter to indicate progression in our sample was the pRNFL thickness

    Morse theory of the moment map for representations of quivers

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    The results of this paper concern the Morse theory of the norm-square of the moment map on the space of representations of a quiver. We show that the gradient flow of this function converges, and that the Morse stratification induced by the gradient flow co-incides with the Harder-Narasimhan stratification from algebraic geometry. Moreover, the limit of the gradient flow is isomorphic to the graded object of the Harder-Narasimhan-Jordan-H\"older filtration associated to the initial conditions for the flow. With a view towards applications to Nakajima quiver varieties we construct explicit local co-ordinates around the Morse strata and (under a technical hypothesis on the stability parameter) describe the negative normal space to the critical sets. Finally, we observe that the usual Kirwan surjectivity theorems in rational cohomology and integral K-theory carry over to this non-compact setting, and that these theorems generalize to certain equivariant contexts.Comment: 48 pages, small revisions from previous version based on referee's comments. To appear in Geometriae Dedicat

    A marking of the cricothyroid membrane with extended neck returns to correct position after neck manipulation and repositioning

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    Background: Emergency front of neck airway access by anaesthetists carries a high failure rate and it is recommended to identify the cricothyroid membrane before induction of anaesthesia in patients with a predicted difficult airway. We have investigated whether a marking of the cricothyroid membrane done in the extended neck position remains correct after the patient's neck has been manipulated and subsequently repositioned METHODS: The subject was first placed in the extended head and neck position and had the cricothyroid membrane identified and marked with three methods, palpation, 'laryngeal handshake' and ultrasonography and the distance from the suprasternal notch to the cricothyroid membrane was measured. The subject then moved off the table and sat on a chair and subsequently returned to the extended neck position and examinations were repeated. Results: Skin markings of all 11 subjects lay within the boundaries of the cricothyroid membrane when the subject was repositioned back to the extended neck position and the median difference between the two measurements of the distance from the suprasternal notch was 0 mm (range 0-2 mm). Conclusion: The cricothyroid membrane can be identified and marked with the subject in the extended neck position. Then the patient's position can be changed as needed, for example to the 'sniffing' neck position for conventional intubation. If a front of neck airway access is required during subsequent airway management, the patient can be returned expediently to the extended-neck position, and the marking of the centre of the membrane will still be in the correct place
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