3,316 research outputs found

    Using eddy covariance to measure the dependence of air–sea CO2 exchange rate on friction velocity

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    Parameterisation of the air–sea gas transfer velocity of CO2 and other trace gases under open-ocean conditions has been a focus of air–sea interaction research and is required for accurately determining ocean carbon uptake. Ships are the most widely used platform for air–sea flux measurements but the quality of the data can be compromised by airflow distortion and sensor cross-sensitivity effects. Recent improvements in the understanding of these effects have led to enhanced corrections to the shipboard eddy covariance (EC) measurements. Here, we present a revised analysis of eddy covariance measurements of air–sea CO2 and momentum fluxes from the Southern Ocean Surface Ocean Aerosol Production (SOAP) study. We show that it is possible to significantly reduce the scatter in the EC data and achieve consistency between measurements taken on station and with the ship underway. The gas transfer velocities from the EC measurements correlate better with the EC friction velocity (u*) than with mean wind speeds derived from shipboard measurements corrected with an airflow distortion model. For the observed range of wind speeds (u10 N = 3–23 m s−1), the transfer velocities can be parameterised with a linear fit to u*. The SOAP data are compared to previous gas transfer parameterisations using u10 N computed from the EC friction velocity with the drag coefficient from the Coupled Ocean–Atmosphere Response Experiment (COARE) model version 3.5. The SOAP results are consistent with previous gas transfer studies, but at high wind speeds they do not support the sharp increase in gas transfer associated with bubble-mediated transfer predicted by physically based models

    Air/sea DMS gas transfer in the North Atlantic: evidence for limited interfacial gas exchange at high wind speed

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    Shipboard measurements of eddy covariance dimethylsulfide (DMS) air–sea fluxes and seawater concentration were carried out in the North Atlantic bloom region in June/July 2011. Gas transfer coefficients (k660) show a linear dependence on mean horizontal wind speed at wind speeds up to 11 m s−1. At higher wind speeds the relationship between k660 and wind speed weakens. At high winds, measured DMS fluxes were lower than predicted based on the linear relationship between wind speed and interfacial stress extrapolated from low to intermediate wind speeds. In contrast, the transfer coefficient for sensible heat did not exhibit this effect. The apparent suppression of air–sea gas flux at higher wind speeds appears to be related to sea state, as determined from shipboard wave measurements. These observations are consistent with the idea that long waves suppress near-surface water-side turbulence, and decrease interfacial gas transfer. This effect may be more easily observed for DMS than for less soluble gases, such as CO2, because the air–sea exchange of DMS is controlled by interfacial rather than bubble-mediated gas transfer under high wind speed conditions

    Injury Risk Estimation Expertise Assessing the ACL Injury Risk Estimation Quiz

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    Background: Available methods for screening anterior cruciate ligament (ACL) injury risk are effective but limited in application as they generally rely on expensive and time-consuming biomechanical movement analysis. A potential efficient alternative to biomechanical screening is skilled movement analysis via visual inspection (ie, having experts estimate injury risk factors based on observations of athletes’ movements). Purpose: To develop a brief, valid psychometric assessment of ACL injury risk factor estimation skill: the ACL Injury Risk Estimation Quiz (ACL-IQ). Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: A total of 660 individuals participated in various stages of the study, including athletes, physicians, physical therapists, athletic trainers, exercise science researchers/students, and members of the general public in the United States. The ACL-IQ was fully computerized and made available online (www.ACL-IQ.org). Item sampling/reduction, reliability analysis, cross-validation, and convergent/discriminant validity analysis were conducted to optimize the efficiency and validity of the assessment. Results: Psychometric optimization techniques identified a short (mean time, 2 min 24 s), robust, 5-item assessment with high reliability (test-retest: r = 0.90) and consistent discriminability (average difference of exercise science professionals vs general population: Cohen d = 1.98). Exercise science professionals and general population individuals scored 74% and 53% correct, respectively. Convergent and discriminant validity was demonstrated. Scores on the ACL-IQ were most associated with ACL knowledge and various cue utilities and were least associated with domain-general spatial/decision-making ability, personality, or other demographic variables. Overall, 23% of the total sample (40% exercise science professionals; 6% general population) performed better than or equal to the ACL nomogram. Conclusion: This study presents the results of a systematic approach to assess individual differences in ACL injury risk factor estimation skill; the assessment approach is efficient (ie, it can be completed in\3 min) and psychometrically robust. The results provide evidence that some individuals have the ability to visually estimate ACL injury risk factors more accurately than other instrument-based ACL risk estimation methods (ie, ACL nomogram). The ACL-IQ provides the foundation for assessing the efficacy of observational ACL injury risk factor assessment (ie, does simple skilled visual inspection reduce ACL injuries?). It also provides a representative task environment that can be used to increase our understanding of the perceptual-cognitive mechanisms underlying observational movement analysis and to improve injury risk assessment performance

    Regulation of neutrophil senescence by microRNAs

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    Neutrophils are rapidly recruited to sites of tissue injury or infection, where they protect against invading pathogens. Neutrophil functions are limited by a process of neutrophil senescence, which renders the cells unable to respond to chemoattractants, carry out respiratory burst, or degranulate. In parallel, aged neutrophils also undergo spontaneous apoptosis, which can be delayed by factors such as GMCSF. This is then followed by their subsequent removal by phagocytic cells such as macrophages, thereby preventing unwanted inflammation and tissue damage. Neutrophils translate mRNA to make new proteins that are important in maintaining functional longevity. We therefore hypothesised that neutrophil functions and lifespan might be regulated by microRNAs expressed within human neutrophils. Total RNA from highly purified neutrophils was prepared and subjected to microarray analysis using the Agilent human miRNA microarray V3. We found human neutrophils expressed a selected repertoire of 148 microRNAs and that 6 of these were significantly upregulated after a period of 4 hours in culture, at a time when the contribution of apoptosis is negligible. A list of predicted targets for these 6 microRNAs was generated from http://mirecords.biolead.org and compared to mRNA species downregulated over time, revealing 83 genes targeted by at least 2 out of the 6 regulated microRNAs. Pathway analysis of genes containing binding sites for these microRNAs identified the following pathways: chemokine and cytokine signalling, Ras pathway, and regulation of the actin cytoskeleton. Our data suggest that microRNAs may play a role in the regulation of neutrophil senescence and further suggest that manipulation of microRNAs might represent an area of future therapeutic interest for the treatment of inflammatory disease

    On chains in HH-closed topological pospaces

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    We study chains in an HH-closed topological partially ordered space. We give sufficient conditions for a maximal chain LL in an HH-closed topological partially ordered space such that LL contains a maximal (minimal) element. Also we give sufficient conditions for a linearly ordered topological partially ordered space to be HH-closed. We prove that any HH-closed topological semilattice contains a zero. We show that a linearly ordered HH-closed topological semilattice is an HH-closed topological pospace and show that in the general case this is not true. We construct an example an HH-closed topological pospace with a non-HH-closed maximal chain and give sufficient conditions that a maximal chain of an HH-closed topological pospace is an HH-closed topological pospace.Comment: We have rewritten and substantially expanded the manuscrip

    Patient perspectives of managing fatigue in ankylosing spondylitis, and views on potential interventions: a qualitative study

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    <p>Background: Fatigue is a major component of living with ankylosing spondylitis (AS), though it has been largely over-looked, and currently there are no specific agreed management strategies.</p> <p>Methods: This qualitative exploratory study involved participants who are members of an existing population-based ankylosing spondylitis (PAS) cohort. Participants residing in South West Wales were invited to participate in a focus group to discuss; (1) effects of fatigue, (2) self-management strategies and (3) potential future interventions. The focus groups were audio-recorded and the transcripts were analysed using thematic analysis.</p> <p>Results: Participants consisted of 3 males/4 females (group 1) and 4 males/3 females (group 2), aged between 35 and 73 years (mean age 53 years). Three main themes were identified: (1) The effects of fatigue were multi-dimensional with participants expressing feelings of being ‘drained’ (physical), ‘upset’ (emotional) and experiencing ‘low-mood’ (psychological); (2) The most commonly reported self-management strategy for fatigue was a balanced combination of activity (exercise) and rest. Medication was reluctantly taken due to side-effects and worries over dependency; (3) Participants expressed a preference for psychological therapies rather than pharmacological for managing fatigue. Information on Mindfulness-Based Stress Reduction (MBSR) was received with interest, with recommendations for delivery in a group format with the option of distance-based delivery for people who were not able to attend a group course.</p> <p>Conclusions: Patients frequently try and manage their fatigue without any formal guidance or support. Our research indicates there is a need for future research to focus on psychological interventions to address the multi-faceted aspects of fatigue in AS.</p&gt

    Dolor posoperatorio en craneotomía

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    In the postoperative period, 47% to 75% of the patients report some degree of pain. This study aimed to evaluate pain in the pre and postoperative period of patients submitted to craniotomy. This prospective research was carried out at the neurosurgery unit of a large Brazilian hospital. For a quantitative evaluation of pain, the verbal numeric 0 - 10 rating scale was used. Forty patients with a mean age of 36 years were evaluated. In the preoperative period, 34 (85%) patients indicated headache as the main cause of pain. In the postoperative period, 37 (93%) patients complained of pain while three (7%) reported absence of pain. Pain peaks were observed on the 2nd postoperative day, when 12 (32%) of the patients reported severe pain and 10 (27%) moderate pain. Absence of severe pain occurred after the 8th postoperative day. It was concluded that protocols of analgesia in craniotomy are needed, such as training nurses to better evaluate and handle pain.En el periodo postoperatorio, entre el 47% y el 75% de los pacientes relatan algún grado de dolor. Los objetivos de este trabajo fueron evaluar el dolor en el pre y postoperatorio de pacientes sometidos a craneotomía. Este estudio prospectivo fue realizado en la unidad de neurocirugía del Hospital São Paulo, Brasil. Para una evaluación cuantitativa del dolor se utilizó la escala numérica verbal graduada de 0 a 10. Fueron evaluados 40 pacientes con edad mediana de 36 años. En el preoperatorio 34 (85%) pacientes, reportaran cefalea como la principal causa del dolor. En el postoperatorio, 37 (93%) pacientes se quejaron de dolor, mientras 3 (7%) pacientes indicaron ausencia de dolor. El pico de dolor fue observado en el segundo día postoperatorio, cuando 12 (32%) pacientes reportaron dolor grave y 10 (27%) moderado. La ausencia de dolor grave ocurrió después del 8º día postoperatorio. Se concluyó que son necesarios protocolos de analgesia en craneotomía, tales como el entrenamiento de enfermeros para mejor evaluar y manejar el dolor.No pós-operatório, 47 a 75% dos pacientes relatam algum grau de dor. O objetivo deste trabalho foi avaliar a dor no pré e pós-operatório de pacientes submetidos a craniotomia. Estudo prospectivo, realizado na unidade de neurocirurgia do Hospital São Paulo. Para avaliação quantitativa de dor, foi utilizada a escala numérica verbal, graduada de 0 a 10. Foram avaliados 40 pacientes, com idade mediana de 36 anos. No pré-operatório, 34 (85%) pacientes relataram cefaléia como a principal causa de dor. No pós-operatório, 37 (93%) pacientes queixaram-se de dor e 3 (7%) pacientes referiram ausência de dor. O pico da dor foi observado no 2º pós-operatório, quando 16 (40%) dos pacientes referiram dor intensa e 11 (28%) queixaram-se de dor moderada. Ausência de dor intensa ocorreu após 6º pós-operatório. Concluí-se que há necessidade de protocolos de analgesia em craniotomia, como treinamento para os enfermeiros para melhor avaliação e manejo da dor.Hospital Israelita Albert EinsteinUniversidade Federal de São Paulo (UNIFESP)UNIFESPSciEL

    Under pressure: Response urgency modulates striatal and insula activity during decision-making under risk

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    When deciding whether to bet in situations that involve potential monetary loss or gain (mixed gambles), a subjective sense of pressure can influence the evaluation of the expected utility associated with each choice option. Here, we explored how gambling decisions, their psychophysiological and neural counterparts are modulated by an induced sense of urgency to respond. Urgency influenced decision times and evoked heart rate responses, interacting with the expected value of each gamble. Using functional MRI, we observed that this interaction was associated with changes in the activity of the striatum, a critical region for both reward and choice selection, and within the insula, a region implicated as the substrate of affective feelings arising from interoceptive signals which influence motivational behavior. Our findings bridge current psychophysiological and neurobiological models of value representation and action-programming, identifying the striatum and insular cortex as the key substrates of decision-making under risk and urgency

    A database of microRNA expression patterns in Xenopus laevis

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    MicroRNAs (miRNAs) are short, non-coding RNAs around 22 nucleotides long. They inhibit gene expression either by translational repression or by causing the degradation of the mRNAs they bind to. Many are highly conserved amongst diverse organisms and have restricted spatio-temporal expression patterns during embryonic development where they are thought to be involved in generating accuracy of developmental timing and in supporting cell fate decisions and tissue identity. We determined the expression patterns of 180 miRNAs in Xenopus laevis embryos using LNA oligonucleotides. In addition we carried out small RNA-seq on different stages of early Xenopus development, identified 44 miRNAs belonging to 29 new families and characterized the expression of 5 of these. Our analyses identified miRNA expression in many organs of the developing embryo. In particular a large number were expressed in neural tissue and in the somites. Surprisingly none of the miRNAs we have looked at show expression in the heart. Our results have been made freely available as a resource in both XenMARK and Xenbase
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