3,427 research outputs found
Non-BBN Constraints On The Key Cosmological Parameters
Since the baryon-to-photon ratio "eta" is in some doubt at present, we ignore
the constraints on eta from big bang nucleosynthesis (BBN) and fit the three
key cosmological parameters (h, Omega_M, eta) to four other observational
constraints: Hubble parameter, age of the universe, cluster gas (baryon)
fraction, and effective shape parameter "Gamma". We consider open and flat CDM
models and flat "Lambda"-CDM models, testing goodness of fit and drawing
confidence regions by the Delta-chi^2 method. CDM models with Omega_M = 1 (SCDM
models) are accepted only because we allow a large error on h, permitting h <
0.5. Open CDM models are accepted only for Omega_M \gsim 0.4. Lambda-CDM models
give similar results. In all of these models, large eta (\gsim 6) is favored
strongly over small eta, supporting reports of low deuterium abundances on some
QSO lines of sight, and suggesting that observational determinations of
primordial 4He may be contaminated by systematic errors. Only if we drop the
crucial Gamma constraint are much lower values of Omega_M and eta permitted.Comment: 12 pages, Kluwer Latex, 2 Postscript figures, to appear in the
proceedings of the ISSI Workshop, "The Primordial Nuclei and Their Galactic
Evolution" (Bern, May 6-10, 1997), ed. N. Prantzos, M. Tosi, and R. von
Steiger (Kluwer, Dordrecht
Detection of catalytic intermediates at an electrode surface during carbon dioxide reduction by an earth-abundant catalyst
The electrocatalytic reduction of CO2 offers a sustainable route to the many carbon fuels and feedstocks that society relies on. [fac-Mn(bpy)(CO)3Br] (bpy, 2,2-bipyridine) is one of the most promising and intensely studied CO2 reduction electrocatalysts. However, the catalytic mechanism remains experimentally unproven and many key intermediates of the prototypical catalyst have not been observed. Here we report the use of vibrational sum-frequency generation spectroscopy to study the catalytic intermediates during CO2 reduction in situ at the electrode surface. We explore the complex applied-potential and acid-dependent mechanistic pathways and provide evidence of the theoretically derived mechanisms. Demonstrating the ability to detect the key species that are only transiently present at the electrode surface is important as the need for an improved mechanistic understanding is a common theme throughout the field of molecular electrocatalysis
Flexible attention allocation to visual and auditory working memory tasks: manipulating reward induces a trade-off
Prominent roles for general attention resources are posited in many models of working memory, but the manner in which these can be allocated differs between models or is not sufficiently specified. We varied the payoffs for correct responses in two temporally-overlapping recognition tasks, a visual array comparison task and a tone sequence comparison task. In the critical conditions, an increase in reward for one task corresponded to a decrease in reward for the concurrent task, but memory load remained constant. Our results show patterns of interference consistent with a trade-off between the tasks, suggesting that a shared resource can be flexibly divided, rather than only fully allotted to either of the tasks. Our findings support a role for a domain-general resource in models of working memory, and furthermore suggest that this resource is flexibly divisible
Exoplanet phase curves: observations and theory
Phase curves are the best technique to probe the three dimensional structure
of exoplanets' atmospheres. In this chapter we first review current exoplanets
phase curve observations and the particular challenges they face. We then
describe the different physical mechanisms shaping the atmospheric phase curves
of highly irradiated tidally locked exoplanets. Finally, we discuss the
potential for future missions to further advance our understanding of these new
worlds.Comment: Fig.5 has been updated. Table 1 and corresponding figures have been
updated with new values for WASP-103b and WASP-18b. Contains a table
sumarizing phase curve observation
A questionnaire to identify patellofemoral pain in the community: an exploration of measurement properties
Background
Community-based studies of patellofemoral pain (PFP) need a questionnaire tool that discriminates between those with and those without the condition. To overcome these issues, we have designed a self-report questionnaire which aims to identify people with PFP in the community.
Methods
Study designs: comparative study and cross-sectional study.
Study population: comparative study: PFP patients, soft-tissue injury patients and adults without knee problems. Cross-sectional study: adults attending a science festival.
Intervention: comparative study participants completed the questionnaire at baseline and two weeks later. Cross-sectional study participants completed the questionnaire once.
The optimal scoring system and threshold was explored using receiver operating characteristic curves, test-retest reliability using Cohen’s kappa and measurement error using Bland-Altman plots and standard error of measurement. Known-group validity was explored by comparing PFP prevalence between genders and age groups.
Results
Eighty-four participants were recruited to the comparative study. The receiver operating characteristic curves suggested limiting the questionnaire to the clinical features and knee pain map sections (AUC 0.97 95 % CI 0.94 to 1.00). This combination had high sensitivity and specificity (over 90 %). Measurement error was less than the mean difference between the groups. Test–retest reliability estimates suggest good agreement (N = 51, k = 0.74, 95 % CI 0.52–0.91). The cross-sectional study (N = 110) showed expected differences between genders and age groups but these were not statistically significant.
Conclusion
A shortened version of the questionnaire, based on clinical features and a knee pain map, has good measurement properties. Further work is needed to validate the questionnaire in community samples
Region of hadron-quark mixed phase in hybrid stars
Hadron--quark mixed phase is expected in a wide region of the inner structure
of hybrid stars. However, we show that the hadron--quark mixed phase should be
restricted to a narrower region to because of the charge screening effect. The
narrow region of the mixed phase seems to explain physical phenomena of neutron
stars such as the strong magnetic field and glitch phenomena, and it would give
a new cooling curve for the neutron star.Comment: to be published in Physical Review
Lesões musculoesqueléticas em policiais militares
INTRODUCTION: The physical qualities need to be analyzed and are risk factors associated with the development of musculoskeletal injuries during military sports training. OBJECTIVE: Epidemiological studies of musculoskeletal injuries occurred in the ankle and foot of military police officers. METHODS: We collected all the medical records of military police officers who have suffered previous injuries in the ankle and foot during the period September 2005 to August 2011. The information was obtained through physical therapy evaluation form found in the records and subsequently the data were tabulated and analyzed. RESULTS: After collecting the data from the medical records, it was found that there 29% bone injuries, 32% ligament injuries and 35% muscle injuries. CONCLUSION: A sprained ankle demonstrates a risk to public health is described by the international statistical classification of diseases and related health problems, which is also in the military environment, described as risk during sports practice.INTRODUCCIÓN: Las cualidades fÃsicas precisan ser analizadas y se vinculan como factores de riesgos para desarrollar lesiones musculoesqueléticas durante el entrenamiento deportivo-militar. OBJETIVO: Recolectar datos sobre epidemiologÃa de las lesiones musculoesqueléticas ocurridas en tobillos y pies de policÃas militares. MATERIALES Y MÉTODOS: Se analizaron todas las fichas médicas de policÃas militares que sufrieron lesiones previas en tobillos y pies durante el perÃodo de septiembre de 2005 a agosto de 2011; las informaciones fueron obtenidas mediante los formularios de evaluación fisioterapéutica que se encontraban en las fichas médicas; posteriormente, los datos obtenidos fueron tabulados y analizados. RESULTADOS: Después de la recolección de datos de las fichas médicas se observó 29% de lesiones óseas, 32% de ligamentarias y 35% de musculares. CONCLUSIÓN: La torcedura de tobillo demuestra ser un riesgo para la salud pública como se describe en la clasificación estadÃstica internacional de enfermedades y problemas relacionados con la salud, siendo en el medio militar señalada también como un riesgo durante la práctica deportiva.INTRODUÇÃO: As qualidades fÃsicas precisam ser analisadas e estão associadas como fatores de risco a desenvolver lesões musculoesqueléticas durante o treinamento esportivo militar. OBJETIVO: Levantar a epidemiologia das lesões musculoesqueléticas ocorridas em tornozelo e pé de policiais militares. MATERIAIS E MÉTODOS: Foram coletados todos os prontuários de policiais militares que sofreram lesões prévias no tornozelo e pé durante o perÃodo de setembro de 2005 a agosto de 2011, as informações foram obtidas através da ficha de avaliação fisioterapêutica constatada nos prontuários, posteriormente os dados obtidos foram tabulados e analisados. RESULTADOS: Após a coleta de dados dos prontuários foi observado que houve 29% de lesões ósseas, 32% de ligamentares e 35% de musculares. CONCLUSÃO: A entorse de tornozelo demonstra um risco à saúde pública como descrita pela classificação estatÃstica internacional de doenças e problemas relacionados à saúde, sendo no meio militar também descrita como um risco durante a prática esportiva.Centro de Reabilitação da PolÃcia MilitarUniversidade Federal de São Paulo (UNIFESP) Centro de Traumatologia do EsporteUNIFESP, Centro de Traumatologia do EsporteSciEL
A novel malaria vaccine candidate antigen expressed in Tetrahymena thermophila
Development of effective malaria vaccines is hampered by the problem of producing correctly folded Plasmodium proteins for use as vaccine components. We have investigated the use of a novel ciliate expression system, Tetrahymena thermophila, as a P. falciparum vaccine antigen platform. A synthetic vaccine antigen composed of N-terminal and C-terminal regions of merozoite surface protein-1 (MSP-1) was expressed in Tetrahymena thermophila. The recombinant antigen was secreted into the culture medium and purified by monoclonal antibody (mAb) affinity chromatography. The vaccine was immunogenic in MF1 mice, eliciting high antibody titers against both N- and C-terminal components. Sera from immunized animals reacted strongly with P. falciparum parasites from three antigenically different strains by immunofluorescence assays, confirming that the antibodies produced are able to recognize parasite antigens in their native form. Epitope mapping of serum reactivity with a peptide library derived from all three MSP-1 Block 2 serotypes confirmed that the MSP-1 Block 2 hybrid component of the vaccine had effectively targeted all three serotypes of this polymorphic region of MSP-1. This study has successfully demonstrated the use of Tetrahymena thermophila as a recombinant protein expression platform for the production of malaria vaccine antigens
- …