1,333 research outputs found

    Treerunners, cryptic lizards of the Plica plica group (Squamata, Sauria, Tropiduridae) of northern South America

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    The arboreal, Neotropical lizard Plica plica (Linnaeus, 1758) has been long considered a widespread species with a distribution east of the Andes. A preliminary examination of 101 specimens from about 28 locations mostly north of the Amazon suggests that Plica plica is a cryptic species complex with taxa that can be distinguished on the basis of the number of scale rows at mid-body; the arrangement, shape and ornamentation of scales on the snout; the number of lamellae on the fourth toe; the number of subocular plates; as well as other commonly used external morphological traits. The allopatric species discussed here are concordant with northern South American geography. Plica plica (Linnaeus,1758) is associated with the Guiana Shield (Suriname, Guyana and Venezuela). A second species, P. caribeana sp. n. is associated with the Caribbean Coastal Range of Venezuela including Trinidad and Tobago. A third, distinctive species, P. rayi sp. n. is associated with the middle Orinoco at the eastern edge of the Guiana Shield. Two other species, P. kathleenae sp. n. and P. medemi sp. n., each based upon a single specimen, one from the Sierra Acarai Mountains of Guyana, and the other from southern Meta, Colombia are described. In addition to morphological analyses, we sequenced 12S and 16S rDNA gene fragments from one Plica plica from Trinidad to assess its relationship and taxonomy to other mainland Plica cf plica. The results suggest Plica caribeana sp. n. likely diverged prior to the separation of Trinidad from northern Venezuela. Isolation in the Caribbean Coastal Range during its rapid uplift in the late Miocene, combined with a marine incursion into northern Venezuela may have contributed to their genetic divergence from other populations. © John C. Murphy, Michael Jowers.Peer Reviewe

    Treerunners, cryptic lizards of the Plica plica group (Squamata, Sauria, Tropiduridae) of northern South America

    Get PDF
    The arboreal, Neotropical lizard Plica plica (Linnaeus, 1758) has been long considered a widespread species with a distribution east of the Andes. A preliminary examination of 101 specimens from about 28 locations mostly north of the Amazon suggests that Plica plica is a cryptic species complex with taxa that can be distinguished on the basis of the number of scale rows at mid-body; the arrangement, shape and ornamentation of scales on the snout; the number of lamellae on the fourth toe; the number of subocular plates; as well as other commonly used external morphological traits. The allopatric species discussed here are concordant with northern South American geography. Plica plica (Linnaeus,1758) is associated with the Guiana Shield (Suriname, Guyana and Venezuela). A second species, P. caribeana sp. n. is associated with the Caribbean Coastal Range of Venezuela including Trinidad and Tobago. A third, distinctive species, P. rayi sp. n. is associated with the middle Orinoco at the eastern edge of the Guiana Shield. Two other species, P. kathleenae sp. n. and P. medemi sp. n., each based upon a single specimen, one from the Sierra Acarai Mountains of Guyana, and the other from southern Meta, Colombia are described. In addition to morphological analyses, we sequenced 12S and 16S rDNA gene fragments from one Plica plica from Trinidad to assess its relationship and taxonomy to other mainland Plica cf plica. The results suggest Plica caribeana sp. n. likely diverged prior to the separation of Trinidad from northern Venezuela. Isolation in the Caribbean Coastal Range during its rapid uplift in the late Miocene, combined with a marine incursion into northern Venezuela may have contributed to their genetic divergence from other populations. © John C. Murphy, Michael Jowers.Peer Reviewe

    Amphibia: Anura: Hylidae Scarthyla vigilans (Solano 1971): Range Extension and New Country Record for Trinidad, W.I. With Notes on Tadpoles, Habitat, Behaviour and Biogeographical Significance.

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    We report a range extension and new country record for Scarthyla vigilans in Trinidad, West Indies. The species was previously known only from populations on mainland South America. We include notes on behavior, habitat and tadpole development, and discuss the biogeographical significance of the species’ presence in Trinidad, particularly with respect to consequences for understanding colonization events on this Caribbean island

    Early recognition and detection of juvenile psoriatic arthritis: a call for a standardized approach to screening

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    Background: National Institute for Health and Care Excellence (NICE) guidelines recommend annual screening for psoriatic arthritis (PsA) in all patients with psoriasis. Currently, no validated assessment tools have been recommended for screening for juvenile PsA (JPsA). Aim: To determine dermatologists' practice when assessing children's joints and explore the challenges dermatologists experience when looking for joint disease, in order to inform future strategies to improve early detection of arthritis. Methods: Structured telephone interviews were undertaken with dermatologists identified through the British Society of Paediatric Dermatology. Percentages for binary and categorized responses were calculated. Thematic content analysis was used to generate a set of core themes across the interview data. Results: Of the 41 consultant dermatologists contacted, 23 agreed to be interviewed. Of these, 78% (18/23) reported they routinely ask about joint disease. Only 13% (3/23) routinely examine the joints of children with psoriasis. Overall, assessment for JPsA lacked a structured, evidence-based approach. The average confidence rating for assessing joint disease was low (score of 3). The two key barriers described for detecting arthritis were a lack of experience and training, and subtle or difficult to detect signs. The two main suggestions for improving detection were the introduction of an assessment tool/guideline and increased clinical experience and training. Conclusion: There is a clear need for dermatologists to use a standardized approach for screening and to increase their confidence in paediatric musculoskeletal examination. In this article, we provide guidance on screening for psoriatic arthritis in children based on our clinical experience

    The epidemiology of childhood psoriasis: a scoping review

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    Psoriasis is an inflammatory noncommunicable skin disease that affects both adults and children. At present, the epidemiology and natural history of psoriasis are not widely understood. This scoping review aimed to map the existing literature on the epidemiology of childhood psoriasis, identify research gaps for future studies and provide a comprehensive, clinically useful review. Search strategies were developed for Ovid Medline, Ovid Embase, Google Scholar and hand searching. In total, 131 articles met the inclusion criteria and were mapped; 107 articles were included for data extraction. Over the last 25 years there has been a dramatic increase in the volume of published observational epidemiological studies on childhood psoriasis. The majority were case series or cross-sectional studies, concentrated in Europe, Asia and North America. The prevalence of childhood psoriasis was found to be higher in European countries, older children and girls. Up to 48·8% of children had a family history of psoriasis in a first-degree relative. The most frequent subtype was plaque psoriasis and the most common initial sites of presentation were the scalp, limbs and trunk. Specific genetic differences have been found between child-onset and adult-onset populations. Case–control and cohort studies investigating risk factors for psoriasis onset, comorbidities and long-term health outcomes were extremely limited. The choice of study design and heterogeneity in methodology limit the validity and generalizability of the information, consistency of the results, and comparability of the studies. Well-designed epidemiological studies are needed to provide precise and consistent information about the frequency and clinical presentation, risk factors, associated diseases and long-term outcomes in childhood psoriasis

    Categorical formulation of quantum algebras

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    We describe how dagger-Frobenius monoids give the correct categorical description of certain kinds of finite-dimensional 'quantum algebras'. We develop the concept of an involution monoid, and use it to construct a correspondence between finite-dimensional C*-algebras and certain types of dagger-Frobenius monoids in the category of Hilbert spaces. Using this technology, we recast the spectral theorems for commutative C*-algebras and for normal operators into an explicitly categorical language, and we examine the case that the results of measurements do not form finite sets, but rather objects in a finite Boolean topos. We describe the relevance of these results for topological quantum field theory.Comment: 34 pages, to appear in Communications in Mathematical Physic

    Effect of osteoarthritis on the repeatability of patella tendon angle measurement in dogs

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    Objective: To evaluate the influence of osteoarthritis on the measurement of patella tendon angle (PTA) and determine intraobserver and interobserver variability. Study design: Retrospective clinical study. Sample population: Eighty‐seven mediolateral radiographs that were obtained prior to tibial tuberosity advancement. Methods: Radiographic osteoarthritis was scored by 2 observers using guidelines derived from the International Elbow Working Group Protocol. Patella tendon angle was measured by 3 observers on 3 occasions, with at least 7 days between measurements. The data were statistically analyzed via weighted κ and Kruskal‐Wallis testing. Results: A fair strength of agreement was found among observers scoring osteoarthritis, with the same grades in 48% of radiographs. The intraobserver average bias between PTA measurements 1 and 3 ranged from −0.38° to −0.94°. Interobserver bias in angle measurement ranged from −0.92° to −2.00°. Observer 1 had the narrowest range of PTA differences (12.1°), and observer 3 had the highest range of PTA differences (23.5°). Observer 2 had the lowest mean bias (−0.38°). The mean bias was lowest between observers 1 and 2 (−0.92°) and highest between observers 1 and 3 (−2.0°). The mean intraobserver standard deviation of the PTA measurement differences was 2.90°, and interobserver standard deviation of the PTA measurement differences was 2.26°. The degree of osteoarthritis did not influence PTA measurements or their variability. Conclusion: The current study did not find evidence of an influence of osteoarthritis on PTA or on the repeatability of measurements. Clinical significance: Our findings suggest that osteoarthritis should not affect the radiographic planning for tibial tuberosity advancement surgery. The high variances in PTA measurement in less experienced observers may influence the clinical outcome of surgery

    Development and psychometric testing of the clinical leadership needs analysis (CLeeNA) instrument for nurses and midwives

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    Aim: The aim of this study is to report the development and psychometric testing of the clinical leadership needs analysis instrument (CLeeNA). Background: Limited emphasis is placed on the clinical leadership needs of nurses and midwives that are fundamental to supporting the delivery of high quality, safe patient care. Methods: A development and validation study of CLeeNA was undertaken using cross-sectional data. A sample of 324 registered nurses and midwives completed the questionnaire using a 7-point adjectival scale. Principal component analysis was conducted to explore scale grouping of items (n = 103 items). Results: Principal component analysis, item reduction and parallel analysis on the items of the instrument resulted in seven factors consisting of 56 items. These factors were identified as: Staff and Care Delivery; Technology and Care Initiatives; Self and Team Development; Standards of Care; Financial and Service Management; Leadership and Clinical Practice; Patient Safety and Risk Management. Conclusion: The identified factors are reflective of an ever-changing health care environment. Implications for Nursing Management: Potentially, after further testing, this instrument could be used by nursing management and educators to measure clinical leadership needs, inform the design of clinical leadership training programmes and provide valuable information about health care leadership development

    Carbon clusters near the crossover to fullerene stability

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    The thermodynamic stability of structural isomers of C24\mathrm{C}_{24}, C26\mathrm{C}_{26}, C28\mathrm{C}_{28} and C32\mathrm{C}_{32}, including fullerenes, is studied using density functional and quantum Monte Carlo methods. The energetic ordering of the different isomers depends sensitively on the treatment of electron correlation. Fixed-node diffusion quantum Monte Carlo calculations predict that a C24\mathrm{C}_{24} isomer is the smallest stable graphitic fragment and that the smallest stable fullerenes are the C26\mathrm{C}_{26} and C28\mathrm{C}_{28} clusters with C2v\mathrm{C}_{2v} and Td\mathrm{T}_{d} symmetry, respectively. These results support proposals that a C28\mathrm{C}_{28} solid could be synthesized by cluster deposition.Comment: 4 pages, includes 4 figures. For additional graphics, online paper and related information see http://www.tcm.phy.cam.ac.uk/~prck
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