2,968 research outputs found

    Irregular Reproductive Cycles in the Tongaland Loggerhead Sea-Turtle, Caretta Caretta L. (Cryptodira: Chelonidae)

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    The concept of sea-turtles exhibiting regular reproductive cycles is widely accepted. In Tongaland, Natal, after 12 years of research 2 122 female loggerhead turtles have been tagged and the recovery rate of tagged animals back on the nesting beaches has reached SO %. From a sample ofthcsc recoveries it is clear that there is no regular reproductive cycle and thus that irregularity is characteristic of this population. The most frequent period of absence from Tongaland is two years but few animals repeat this absence cyclically. Results 80 far indicate that a loggerhead female can nest for at least four seasons spread over a period of at least nine years

    Body Temperature of the Loggerhead Sea Turtle Caretta Caretta and the Leatherback Sea Turtle Dermochelys Coriacea During Nesting

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    Body temperatures of loggerhead and leatherback turtles recorded during nesting excursions were found to be greater than sea temperatures. Leatherback turtles exhibited greater temperature differentials (5,3 - 6,25°C) than loggerhead turtles (1,9 - 3,22°C).The possibility that leatherback turtles may have a preferred temperature range (30 - 32°C) as is the case in terrestrial chelonians is discussed. Recordings of exhaled air temperatures suggest that leather-back turtles may employ a countercurrent heat exchange system in the nares in order to conserve body heat

    On Semiclassical Limits of String States

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    We explore the relation between classical and quantum states in both open and closed (super)strings discussing the relevance of coherent states as a semiclassical approximation. For the closed string sector a gauge-fixing of the residual world-sheet rigid translation symmetry of the light-cone gauge is needed for the construction to be possible. The circular target-space loop example is worked out explicitly.Comment: 12 page

    Hawk Eyes I: Diurnal Raptors Differ in Visual Fields and Degree of Eye Movement

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    BACKGROUND: Different strategies to search and detect prey may place specific demands on sensory modalities. We studied visual field configuration, degree of eye movement, and orbit orientation in three diurnal raptors belonging to the Accipitridae and Falconidae families. METHODOLOGY/PRINCIPAL FINDINGS: We used an ophthalmoscopic reflex technique and an integrated 3D digitizer system. We found inter-specific variation in visual field configuration and degree of eye movement, but not in orbit orientation. Red-tailed Hawks have relatively small binocular areas (∼33°) and wide blind areas (∼82°), but intermediate degree of eye movement (∼5°), which underscores the importance of lateral vision rather than binocular vision to scan for distant prey in open areas. Cooper's Hawks' have relatively wide binocular fields (∼36°), small blind areas (∼60°), and high degree of eye movement (∼8°), which may increase visual coverage and enhance prey detection in closed habitats. Additionally, we found that Cooper's Hawks can visually inspect the items held in the tip of the bill, which may facilitate food handling. American Kestrels have intermediate-sized binocular and lateral areas that may be used in prey detection at different distances through stereopsis and motion parallax; whereas the low degree eye movement (∼1°) may help stabilize the image when hovering above prey before an attack. CONCLUSIONS: We conclude that: (a) there are between-species differences in visual field configuration in these diurnal raptors; (b) these differences are consistent with prey searching strategies and degree of visual obstruction in the environment (e.g., open and closed habitats); (c) variations in the degree of eye movement between species appear associated with foraging strategies; and (d) the size of the binocular and blind areas in hawks can vary substantially due to eye movements. Inter-specific variation in visual fields and eye movements can influence behavioral strategies to visually search for and track prey while perching

    Timing and Dose of Upper Limb Motor Intervention After Stroke: A Systematic Review

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    This systematic review aimed to investigate timing, dose, and efficacy of upper limb intervention during the first 6 months poststroke. Three online databases were searched up to July 2020. Titles/abstracts/full-text were reviewed independently by 2 authors. Randomized and nonrandomized studies that enrolled people within the first 6 months poststroke, aimed to improve upper limb recovery, and completed preintervention and postintervention assessments were included. Risk of bias was assessed using Cochrane reporting tools. Studies were examined by timing (recovery epoch), dose, and intervention type. Two hundred and sixty-one studies were included, representing 228 (n=9704 participants) unique data sets. The number of studies completed increased from one (n=37 participants) between 1980 and 1984 to 91 (n=4417 participants) between 2015 and 2019. Timing of intervention start has not changed (median 38 days, interquartile range [IQR], 22–66) and study sample size remains small (median n=30, IQR 20–48). Most studies were rated high risk of bias (62%). Study participants were enrolled at different recovery epochs: 1 hyperacute (<24 hours), 13 acute (1–7 days), 176 early subacute (8–90 days), 34 late subacute (91–180 days), and 4 were unable to be classified to an epoch. For both the intervention and control groups, the median dose was 45 (IQR, 600–1430) min/session, 1 (IQR, 1–1) session/d, 5 (IQR, 5–5) d/wk for 4 (IQR, 3–5) weeks. The most common interventions tested were electromechanical (n=55 studies), electrical stimulation (n=38 studies), and constraint-induced movement (n=28 studies) therapies. Despite a large and growing body of research, intervention dose and sample size of included studies were often too small to detect clinically important effects. Furthermore, interventions remain focused on subacute stroke recovery with little change in recent decades. A united research agenda that establishes a clear biological understanding of timing, dose, and intervention type is needed to progress stroke recovery research. Prospective Register of Systematic Reviews ID: CRD42018019367/CRD42018111629

    Future enhanced clinical role of pharmacists in emergency departments in England:multi-site observational evaluation

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    Background There are concerns about maintaining appropriate clinical staffing levels in Emergency Departments. Pharmacists may be one possible solution. Objective To determine if Emergency Department attendees could be clinically managed by pharmacists with or without advanced clinical practice training. Setting Prospective 49 site cross-sectional observational study of patients attending Emergency Departments in England. Method Pharmacist data collectors identified patient attendance at their Emergency Department, recorded anonymized details of 400 cases and categorized each into one of four possible options: cases which could be managed by a community pharmacist; could be managed by a hospital pharmacist independent prescriber; could be managed by a hospital pharmacist independent prescriber with additional clinical training; or medical team only (unsuitable for pharmacists to manage). Impact indices sensitive to both workload and proportion of pharmacist manageable cases were calculated for each clinical group. Main outcome measure Proportion of cases which could be managed by a pharmacist. Results 18,613 cases were observed from 49 sites. 726 (3.9%) of cases were judged suitable for clinical management by community pharmacists, 719 (3.9%) by pharmacist prescribers, 5202 (27.9%) by pharmacist prescribers with further training, and 11,966 (64.3%) for medical team only. Impact Indices of the most frequent clinical groupings were general medicine (13.18) and orthopaedics (9.69). Conclusion The proportion of Emergency Department cases that could potentially be managed by a pharmacist was 36%. Greatest potential for pharmacist management was in general medicine and orthopaedics (usually minor trauma). Findings support the case for extending the clinical role of pharmacists

    The utility of c-Met as a diagnostic tissue biomarker in primary colorectal cancer

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    The transmembrane protein, c-Met, is thought to be overexpressed and activated in colorectal cancer (CRC). This study explored its potential as a diagnostic tissue biomarker for CRC in a large human CRC tissue collection obtained from a randomized clinical trial. Tissue microarrays of matched normal colorectal epithelium and primary cancer were prepared from specimens obtained from 280 patients recruited to the MRC CLASICC trial (ISRCTN 74883561) and interrogated using immunohistochemistry for c-Met expression. The distribution and intensity of immunopositivity was graded using a validated, semi-quantifiable score, and differences in median scores analysed using the Wilcoxon signed-rank test. A receiver operating characteristic (ROC) curve was plotted to measure the diagnostic accuracy of c-Met as a biomarker in CRC. Epithelial cell membrane expression of c-Met differed significantly between CRC and normal colorectal tissue: median 12.00 (Interquartile range (IQR) 6-15) versus median 6.00 (IQR 2.70-12.00) respectively (P = <.0001). ROC-AUC analysis of c-Met expression yielded a CRC diagnostic probability of 0.66 (95% CI: 0.61 to 0.70; P < .0001). A score of ≥14.50 showed high specificity at 85.32% (95% CI 80.33%-89.45%) but sensitivity of only 30.92% (CI 25.37%-36.90%). Thus c-Met is consistently overexpressed in human CRC as compared to normal colorectal epithelium tissue. c-Met expression may have a role in diagnosis and prognostication if combined with other biomarkers
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