1,866 research outputs found

    Histological evidence for a supraspinous ligament in sauropod dinosaurs

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    Supraspinous ossified rods have been reported in the sacra of some derived sauropod dinosaurs. Although different hypotheses have been proposed to explain the origin ofthis structure, histological evidence has never been provided to support or reject any of them. In order to establish its origin, we analyse and characterize the microstructure of thesupraspinous rod of two sauropod dinosaurs from the Upper Cretaceous of Argentina. The supraspinous ossified rod is almost entirely formed by dense Haversian bone. Remains ofprimary bone consist entirely of an avascular tissue composed of two types of fibre-like structures, which are coarse and longitudinally (parallel to the main axis of the element) oriented. These structures are differentiated on the basis of their optical properties under polarized light. Very thin fibrous strands are also observed in some regions. These small fibres are all oriented parallel to one another but perpendicular to the element main axis. Histological features of the primary bone tissue indicate that the sacral supraspinous rod corresponds to an ossified supraspinous ligament. The formation of this structure appears to have been a non-pathological metaplastic ossification, possibly induced by the continuous tensile forces applied to the element.Fil: Cerda, Ignacio Alejandro. Consejo Nacional de Investigaciones CientΓ­ficas y TΓ©cnicas. Centro CientΓ­fico TecnolΓ³gico Conicet - Patagonia Norte. Instituto de InvestigaciΓ³n en PaleobiologΓ­a y GeologΓ­a; Argentina. Universidad Nacional de RΓ­o Negro; ArgentinaFil: Casal, Gabriel. Universidad Nacional de la Patagonia; ArgentinaFil: MartΓ­nez, RubΓ©n DarΓ­o. Universidad Nacional de la Patagonia ; ArgentinaFil: Ibiricu, Lucio Manuel. Consejo Nacional de Investigaciones CientΓ­ficas y TΓ©cnicas. Centro Nacional PatagΓ³nico; Argentin

    Case report and literature review: transient Inab phenotype and an agglutinating anti-IFC in a patient with a gastrointestinal problem

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    The Inab phenotype is a rare deficiency of all Cromer antigens. These antigens are carried on the decay-accelerating factor (DAF, CD55) molecule that is attached to the red blood cell (RBC) membrane by a glycosylphosphatidylinositol (GPI) anchor. Although typically inherited, an acquired and transient form of the Inab phenotype also exists. A patient with the triad of transient Inab phenotype, a direct-agglutinating anti-IFC, and gastrointestinal (GI) abnormalities is reported. CASE REPORT: An 18-month-old boy with gastroesophageal reflux disease requiring a feeding tube, milk and soy intolerance, and severe growth retardation, as well as vision and hearing deficits from cytomegalovirus infection, was identified when pretransfusion testing revealed a potent panagglutinin (titer > 2000 at 4Β°C). This antibody did not react with Dr(a–) and IFC RBCs, and the autocontrol was negative. The patient’s RBCs lacked CD55 by flow cytometric techniques but had normal levels of CD59 and antigens such as Yt a and Emm, carried on GPI-linked proteins, thus excluding paroxysmal nocturnal hemoglobinuria. Several months after initial detection, the anti-IFC was virtually undetectable and his cells reacted weakly with anti-IFC, anti-Dr a , and anti-CD55. RBCs from the propositus’ parents and brother demonstrated normal CD55 and CD59 expression. CONCLUSION: This is the first example of a direct-agglutinating anti-IFC. The cause of the transient depression in CD55 protein (and thus Cromer system antigens) and appearance of anti-IFC remains unknown, as does the relationship between the patient’s GI system abnormalities and these serologic findings.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/71992/1/j.1537-2995.2006.00933.x.pd

    Fatigue Intervention by Nurses Evaluation - The FINE Trial. A randomised controlled trial of nurse led self-help treatment for patients in primary care with chronic fatigue syndrome: study protocol. [ISRCTN74156610]

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    Background: Chronic fatigue syndrome, also known as ME (CFS/ME), is a condition characterised primarily by severe, disabling fatigue, of unknown origin, which has a poor prognosis and serious personal and economic consequences. Evidence for the effectiveness of any treatment for CFS/ME in primary care, where most patients are seen, is sparse. Recently, a brief, pragmatic treatment for CFS/ME, based on a physiological dysregulation model of the condition, was shown to be successful in improving fatigue and physical functioning in patients in secondary care. The treatment involves providing patients with a readily understandable explanation of their symptoms, from which flows the rationale for a graded rehabilitative plan, developed collaboratively with the therapist. The present trial will test the effectiveness and cost-effectiveness of pragmatic rehabilitation when delivered by specially trained general nurses in primary care. We selected a client-centred counselling intervention, called supportive listening, as a comparison treatment. Counselling has been shown to be as effective as cognitive behaviour therapy for treating fatigue in primary care, is more readily available, and controls for supportive therapist contact time. Our control condition is treatment as usual by the general practitioner (GP). Methods and design: This study protocol describes the design of an ongoing, single-blind, pragmatic randomized controlled trial of a brief (18 week) self-help treatment, pragmatic rehabilitation, delivered by specially trained nurse-therapists in patients' homes, compared with nurse-therapist delivered supportive listening and treatment as usual by the GP. An economic evaluation, taking a societal viewpoint, is being carried out alongside the clinical trial. Three adult general nurses were trained over a six month period to deliver the two interventions. Patients aged over 18 and fulfilling the Oxford criteria for CFS are assessed at baseline, after the intervention, and again one year later. Primary outcomes are self-reported physical functioning and fatigue at one year, and will be analysed on an intention-to-treat basis. A qualitative study will examine the interventions' mechanisms of change, and also GPs' drivers and barriers towards referral

    Structural properties of mobile armors formed at different flow strengths in gravel-bed rivers

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    Differences in the structure of mobile armors formed at three different flow strengths have been investigated in a laboratory flume. The temporal evolution of the bed surfaces and the properties of the final beds were compared using metrics of surface grain size, microtopography, and bed organization at both grain and mesoscales. Measurements of the bed condition were obtained on nine occasions during each experiment to describe the temporal evolution of the beds. Structured mobile armors formed quickly in each experiment. At the grain scale (1–45 mm; 9 ≀ Ds50 ≀ 17 mm where Ds50 is the median surface particle size), surface complexity decreased and bed roughness increased in response to surface coarsening and the development of the mobile armor. Particles comprising the armor also became flow aligned and developed imbrication. At a larger scale (100–200 mm), the surface developed a mesoscale topography through the development of bed patches with lower and higher elevations. Metrics of mobile armor structure showed remarkable consistency over prolonged periods of near-constant transport, demonstrating for the first time that actively transporting surfaces maintain an equilibrium bed structure. Bed structuring was least developed in the experiments conducted at the lowest flow strength. However, little difference was observed in the structural metrics of the mobile armors generated at higher flows. Although the range of transport rates studied was limited, the results suggest that the structure of mobile armors is insensitive to the formative transport rate except when rates are low (Ο„*β€‰β‰ˆβ€‰0.03 where Ο„* is the dimensionless shear stress)

    Single-field inflation constraints from CMB and SDSS data

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    We present constraints on canonical single-field inflation derived from WMAP five year, ACBAR, QUAD, BICEP data combined with the halo power spectrum from SDSS LRG7. Models with a non-scale-invariant spectrum and a red tilt n_s < 1 are now preferred over the Harrison-Zel'dovich model (n_s = 1, tensor-to-scalar ratio r = 0) at high significance. Assuming no running of the spectral indices, we derive constraints on the parameters (n_s, r) and compare our results with the predictions of simple inflationary models. The marginalised credible intervals read n_s = 0.962^{+0.028}_{-0.026} and r < 0.17 (at 95% confidence level). Interestingly, the 68% c.l. contours favour mainly models with a convex potential in the observable region, but the quadratic potential model remains inside the 95% c.l. contours. We demonstrate that these results are robust to changes in the datasets considered and in the theoretical assumptions made. We then consider a non-vanishing running of the spectral indices by employing different methods, non-parametric but approximate, or parametric but exact. With our combination of CMB and LSS data, running models are preferred over power-law models only by a Delta chi^2 ~ 5.8, allowing inflationary stages producing a sizable negative running -0.063^{+0.061}_{-0.049} and larger tensor-scalar ratio r < 0.33 at the 95% c.l. This requires large values of the third derivative of the inflaton potential within the observable range. We derive bounds on this derivative under the assumption that the inflaton potential can be approximated as a third order polynomial within the observable range.Comment: 32 pages, 7 figures. v2: additional references, some typos corrected, passed to JCAP style. v3: minor changes, matches published versio

    Preparation, structured deliberate practice and decision making in elite level football: The case study of Gary Neville (Manchester United FC and England)

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    Decision making in elite level sporting competition is often regarded as distinguishing success from failure. As an intricate brain-based process it is unlike other physical processes because it is invisible and is typically only evidenced after the event. This case study shows how an individual achieved great success in elite level professional football through consistent positive decision making on and off the field of play. Through prolonged interviewing, Gary Neville, a player from Manchester United Football Club, explored personal behaviours, the structure and activities of deliberate practice and his professional choices in match preparation. His career-long devotion to purposeful organised practice was focused on cognition, physical preparation, context-relative physical action and refined repetition to optimise his mental comfort while enhancing his match day performances. This approach was underpinned by diligent personal and collective organisation and by concerted action. Results provide an insight into the categorical nature of his deliberate practice, sport-specific information processing and match-based decision making. At the operational level, his process was mediated by a complex mental representation of ongoing and anticipated game situations; these representations were continuously updated during each match. Allowing for the limitations of the design, implications are provided for developmental and educational coaching, match preparation, deliberate practice activity and improved use of the performance analysis software packages in professional football

    Respiratory plasticity in response to changes in oxygen supply and demand

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    Aerobic organisms maintain O2 homeostasis by responding to changes in O2 supply and demand in both short and long time domains. In this review, we introduce several specific examples of respiratory plasticity induced by chronic changes in O2 supply (environmental hypoxia or hyperoxia) and demand (exercise-induced and temperature-induced changes in aerobic metabolism). These studies reveal that plasticity occurs throughout the respiratory system, including modifications to the gas exchanger, respiratory pigments, respiratory muscles, and the neural control systems responsible for ventilating the gas exchanger. While some of these responses appear appropriate (e.g., increases in lung surface area, blood O2 capacity, and pulmonary ventilation in hypoxia), other responses are potentially harmful (e.g., increased muscle fatigability). Thus, it may be difficult to predict whole-animal performance based on the plasticity of a single system. Moreover, plastic responses may differ quantitatively and qualitatively at different developmental stages. Much of the current research in this field is focused on identifying the cellular and molecular mechanisms underlying respiratory plasticity. These studies suggest that a few key molecules, such as hypoxia inducible factor (HIF) and erythropoietin, may be involved in the expression of diverse forms of plasticity within and across species. Studying the various ways in which animals respond to respiratory challenges will enable a better understanding of the integrative response to chronic changes in O2 supply and deman
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