1,517 research outputs found
Long-term Stellar Variability in the Galactic Centre Region
© 2019 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.We report the detection of variable stars within a 11.5' x 11.5' region near the Galactic centre (GC) that includes the Arches and Quintuplet clusters, as revealed by the VISTA Variables in the Via Lactea (VVV) survey. There are 353 sources that show Ks-band variability, of which the large majority (81%) correspond to red giant stars, mostly in the asymptotic giant branch (AGB) phase. We analyze a population of 52 red giants with long-term trends that cannot be classified into the typical pulsating star categories. Distances and extinctions are calculated for 9 Mira variables, and we discuss the impact of the chosen extinction law on the derived distances. We also report the presence of 48 new identified young stellar object (YSO) candidates in the region.Peer reviewe
Equivalent Circuit for Double Annular Aperture Frequency Selective Surfaces
In this work a double annular aperture frequency selective surface is analyzed from an equivalent circuit perspective. A comparison between full wave numerical solution and the proposed equivalent circuit results is provided for different examples. A very good agreement is obtained endowing the equivalent circuit with great potential as a very powerful and efficient design tool for advanced space filters
Impact of effectual propensity on entrepreneurial intention
For decades, entrepreneurship has been promoted in academia and the tourism sector and seen as an opportunity for new business ventures. In entrepreneurial behaviour, effectual logic shows how individuals use their resources to create new opportunities. This paper aims to determine effectual propensity as an antecedent of entrepreneurial intentions. For this purpose, and based on the TPB model, we conducted our research with tourism students from Cadiz and Seville (Spain) universities with Smart PLS 3. The results show that effectual propensity influences entrepreneurial intentions and that attitude and perceived behavioural control mediate between subjective norms and intentions. Our research has a great added value since effectual propensity is studied for the first time as an antecedent of intentions in people who have never been entrepreneurs.Durante décadas, el emprendimiento ha sido promovido en la academia y el sector del turismo, siendo visto como una oportunidad para nuevas empresas. En el comportamiento emprendedor, la lógica efectual muestra cómo los individuos utilizan sus recursos para crear nuevas oportunidades. Este documento tiene como objetivo determinar la propensión efectual como un antecedente de las intenciones emprendedoras. Con este propósito, y basándonos en el modelo TPB, llevamos a cabo nuestra investigación con estudiantes de turismo de las universidades de Cádiz y Sevilla (España) utilizando Smart PLS 3. Los resultados muestran que la propensión efectual influye en las intenciones emprendedoras y que la actitud y el control conductual percibido median entre las normas subjetivas e intenciones. Nuestra investigación tiene un gran valor agregado, ya que la propensión efectual se estudia por primera vez como antecedente de intenciones en personas que nunca han sido emprendedoras
Fractura de Maisonneuve abierta: una entidad infrecuente: a propósito de un caso y revisión de la literatura
Introducción. La fractura de Maisonneuve representa aproximadamente el 5% de todas las fracturas
de tobillo tratadas quirúrgicamente. Debido a que suelen ser fracturas cerradas, presentamos el caso de una
fractura de Maisonneuve abierta por su infrecuencia. Caso Clínico. Varón de 63 años que acudió a urgencias
tras traumatismo de miembro inferior derecho. En la exploración se evidenció una solución de continuidad de la
piel en cara medial de tobillo con exposición de maléolo tibial. La radiografía mostró una apertura de la mortaja
tibio-peronea y una fractura espiroidea en el tercio proximal del peroné. Se realizó osteosíntesis con dos tornillos
canulados. Tras 12 meses de seguimiento, el paciente presenta una puntuación media de 86,8 puntos en la escala
AOFAS. Conclusión. Ante una luxación abierta de tobillo, debe sospecharse una fractura de Maisonneuve aunque
sea poco frecuente, siendo la osteosíntesis una opción terapéutica eficaz en este tipo de fracturas.Introduction. Maisonneuve fracture represents approximately 5% of all surgically treated ankle
fractures. Because these fractures are usually closed, we present the case of a Maisonneuve open fracture owing
to its rarity. Case report. A 63-year-old man presented to his emergency department after a right leg trauma.
Physical examination revealed a skin solution of continuity above the ankle joint, with a medial tibial malleolus
exposure. The radiography showed an opening of the tibiofibular mortise and a spiral fracture of the proximal
third of the fibula. Fixation with two cannulated screws was performed. After 12 months of follow up, the patient
has an average score of 86.8 points on the AOFAS scale. Conclusion. In the face of an open ankle dislocation, a
Maisonneuve open fracture should be suspected in spite of its infrequency, being the osteosynthesis an effective
therapeutic option in this type of fracture
Challenges of accessibility of a community heritage tourist route: The Route of the Caste War
This article presents the results of an accessibility analysis of The Caste War Route (RGC), prior to its commercialization as a community heritage product. The analysis consists of a diagnosis of the resource to establish destination-planning strategies. The accessibility diagnosis goes beyond adapting physical spaces for transit, considering that the resource is accessible to all types of people, including economic, spatial and temporal accessibility, criteria on which the research focuses.
The diagnosis was prepared through a multidisciplinary investigation that collected information from different sectors with qualitative and quantitative tools that combined the recording of data and the opinion of the residents of the area, key informants; Government officials, museum workers, tourism service providers, non-governmental organizations and visitors were included in this research.
Accessibility is a multivariate concept; its analysis required an instrument with cultural indicators distributed in categories, which provides objective, rigorous and relevant information. The research approach was qualitative, including Participatory Action Research and ethnographic techniques such as participant observation (PAR), interviews and document review as part of the process.
It is necessary to propose promotional strategies focused on rural cultural products, that disseminate the sites and activities considered heritage by the community, and that the inhabitants are willing to share with visitors, so that local hosts are the ones who offer this service.
The necessary strategies are the equal participation and involvement of women and men, the participation of students and academics in training courses and orientation to local service providers. These products face important challenges: they must differentiate themselves from others to build a unique local identity, and at the same time, form alliances with other local communities to create and strengthen local tourism products and services to create a complete touristic experience versus isolated experiences in individual communities. Achieving integration is essential for a successful project and the regional growth and development of the localities involved
Oxidative Damage to DNA and Lipids as Biomarkers of Exposure to Air Pollution
Ba c k g r o u n d: Air pollution is thought to exert health effects through oxidative stress, which causes damage to DNA and lipids. Obj e c t i v e: We determined whether levels of oxidatively damaged DNA and lipid peroxidation products in cells or bodily fluids from humans are useful biomarkers of biologically effective dose in studies of the health effects of exposure to particulate matter (PM) from combustion processes. Data s o u r c e s: We identified publications that reported estimated associations between environmental exposure to PM and oxidative damage to DNA and lipids in PubMed and EMBASE. We also identified publications from reference lists and articles cited in the Web of Science. Data extraction: For each study, we obtained information on the estimated effect size to calculate the standardized mean difference (unitless) and determined the potential for errors in exposure assessment and analysis of each of the biomarkers, for total and stratified formal meta-analyses. Data synthesis: In the meta-analysis, the standardized mean differences (95 % confidence interval) between exposed and unexposed subjects for oxidized DNA and lipids were 0.53 (0.29–0.76) and 0.73 (0.18–1.28) in blood and 0.52 (0.22–0.82) and 0.49 (0.01–0.97) in urine, respectively. The standardized mean difference for oxidized lipids was 0.64 (0.07–1.21) in the airways. Restricting analyses to studies unlikely to have substantial biomarker or exposure measurement error, studies likely to have biomarker and/or exposure error, or studies likely to have both sources of error resulted in standardized mean differences of 0.55 (0.19–0.90), 0.66 (0.37–0.95), and 0.65 (0.34–0.96), respectively. Co n c l u s i o n s: Exposure to combustion particles is consistenly associated with oxidatively damaged DNA and lipids in humans, suggesting that it is possible to use these measurements as biomarkers of biologically effective dose. Key w o r d s: biomarker, DNA damage, lipid peroxidation products, oxidative stress, particulate matter. Environ Health Perspect 118:1126–1136 (2010). doi:10.1289/ehp.0901725 [Onlin
Validation of models with constant bias: an applied approach
Objective. This paper presents extensions to the statistical validation method based on the procedure of Freese when a model shows constant bias (CB) in its predictions and illustrate the method with data from a new mechanistic model that predict weight gain in cattle. Materials and methods. The extensions were the hypothesis tests and maximum anticipated error for the alternative approach, and the confidence interval for a quantile of the distribution of errors. Results. The model evaluated showed CB, once the CB is removed and with a confidence level of 95%, the magnitude of the error does not exceed 0.575 kg. Therefore, the validated model can be used to predict the daily weight gain of cattle, although it will require an adjustment in its structure based on the presence of CB to increase the accuracy of its forecasts. Conclusions. The confidence interval for the 1-α quantile of the distribution of errors after correcting the constant bias, allows determining the top limit for the magnitude of the error of prediction and use it to evaluate the evolution of the model in the forecasting of the system. The confidence interval approach to validate a model is more informative than the hypothesis tests for the same purpose
NP7 protects from cell death induced by oxidative stress in neuronal and glial midbrain cultures from parkin null mice
AbstractParkin mutations produce Parkinson’s disease (PD) in humans and nigrostriatal dopamine lesions related to increased free radicals in mice. We examined the effects of NP7, a synthetic, marine derived, free radical scavenger which enters the brain, on H2O2 toxicity in cultured neurons and glia from wild-type (WT) and parkin null mice (PK-KO).NP7, 5–10μM, prevented the H2O2 induced apoptosis and necrosis of midbrain neuronal and glial cultures from WT and PK-KO mice. NP7 suppressed microglial activation and the H2O2 induced drop-out of dopamine neurons. Furthermore, NP7 prevented the increased phosphorylation of ERK and AKT induced by H2O2. NP7 may be a promising neuroprotector against oxidative stress in PD
Association of increased fibrinogen concentration with impaired activation of anticoagulant protein C
BACKGROUND: Low levels of activated protein C (APC) are a risk factor for venous thrombosis. The mechanisms leading to interindividual differences in APC are not totally elucidated. Protein C is activated by the thrombin-thrombomodulin complex. As thrombin binds to fibrinogen and thrombomodulin through a common region, it is conceivable that fibrinogen influences the activation of protein C. This would help to explain the association between high levels of fibrinogen and an increased thrombotic risk.
METHODS: We analyzed the association between circulating APC levels and fibrinogen concentration in 382 healthy subjects. Subsequently, we studied the effect of increasing fibrinogen concentrations on the APC generation on cultured endothelial cells.
RESULTS: An independent inverse association between circulating APC levels and fibrinogen was found [betacoefficient, -0.16; 95% confidence interval (95% CI) -0.26, -0.06; P = 0.001]. For each 100 mg dL(-1) increase in fibrinogen, the independent risk of having low APC levels (<0.7 ng mL(-1)) was almost three times higher (OR 2.8; 95% CI 1.1, 7.2; P = 0.04). Accordingly, a notable association between increasing fibrinogen concentrations and the reduction in the thrombin-thrombomodulin dependent activation of protein C on endothelial cells was found (r = -0.57; P = 0.002).
CONCLUSIONS: We present evidence of an inverse association between circulating APC and fibrinogen levels. According to this finding together with the results of our in vitro experiments, we propose that the impairment in the generation of APC on endothelial cells constitutes a new prothrombotic mechanism of fibrinogen
- …