2,014 research outputs found

    Physical Examination Tests for Screening and Diagnosis of Cervicogenic Headache: A Systematic Review

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    It has been suggested that differential diagnosis of headaches should consist of a robust subjective ex-amination and a detailed physical examination of the cervical spine. Cervicogenic headache (CGH) is a form of headache that involves referred pain from the neck. To our knowledge, no studies have sum-marized the reliability and diagnostic accuracy of physical examination tests for CGH. The aim of this study was to summarize the reliability and diagnostic accuracy of physical examination tests used to diagnose CGH. A systematic review following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines was performed in four electronic databases (MEDLINE, Web of Science, Embase and Scopus). Full text reports concerning physical tests for the diagnosis of CGH which reported the clinometric properties for assessment of CGH, were included and screened for methodological quality. Quality Appraisal for Reliability Studies (QAREL) and Quality Assessment of Studies of Diagnostic Accuracy (QUADAS-2) scores were completed to assess article quality. Eight articles were retrieved for quality assessment and data extraction. Studies investigating diagnostic reliability of physical exami-nation tests for CGH scored poorer on methodological quality (higher risk of bias) than those of diag-nostic accuracy. There is sufficient evidence showing high levels of reliability and diagnostic accuracy of the selected physical examination tests for the diagnosis of CGH. The cervical flexion-rotation test (CFRT) exhibited both the highest reliability and the strongest diagnostic accuracy for the diagnosis of CGH

    Rotten Egg Nebula: The magnetic field of a binary evolved star

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    Most of PNe are not spherical. The loss of spherical symmetry occurs somewhere between the AGB and PN phase. The cause of this change of morphology is not yet well known, but magnetic fields are one of the possible agents. Its origin remains to be determined, and potentially requires the presence of a massive companion to the AGB star. Therefore, further detections of the magnetic field around evolved stars (in particular those thought to be part of a binary system) are crucial to improve our understanding of the origin and role of magnetism on evolved stars. One such binaries is the pre-PN OH231.8, around which a magnetic field was detected in the OH maser region of the outer circumstellar envelope. We aim to detect and infer the properties of the magnetic field of this source in the water maser region. We observed the 6_{1,6}-5_{2,3} water maser rotational transition to determine its linear and circular polarization. These emissions are located within the inner regions of OH231.8 (at few tens of AU). We detected 30 water maser features, which occur in two distinct regions that are moving apart with a velocity on the sky of 2.3 mas/year. Taking into account the inclination angle of the source, this corresponds to an average separation velocity of 21 km/s. Based on the velocity gradient of the maser emission, the masers appear to be dragged along the direction of the nebula jet. Linear polarization is present in 3 of the features, and circular polarization was detected in the 2 brightest ones. We found that the strength of the magnetic field is |B_{||}|~45 mG which, when assuming a toroidal magnetic field, implies B~2.5 G on the stellar surface. The morphology of the field is not yet determined, but the high scatter found on the directions of the linear polarization vectors could indicate that the masers occur near the tangent points of a toroidal field.Comment: 7 pages, 4 figure

    Effects of pulsed electric field on the viscoelastic properties of potato tissue

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    We have investigated whether transient permeabilization caused by the application of pulsed electric field would give rise to transient changes in the potato tissue viscoelastic properties. Potato tissue was subjected to nominal field strengths (E) ranging from 30 to 500 V/cm, with a single rectangular pulse of 10−5, 10−4, or 10−3 s. The changes on the viscoelastic properties of potato tissue during pulsed electric fields (PEF) were monitored through small amplitude oscillatory dynamic rheological measurements. The elastic (G′) and viscous moduli (G″) were measured every 30 s after the delivery of the pulse and the loss tangent change (tan-δ) was calculated. The results were correlated with measurements of changes on electrical resistance during the delivery of the pulse. Results show a drastic increase of tan-δ in the first 30 s after the application of the pulse, followed by a decrease 1 min after pulsation. This response is strongly influenced by pulsing conditions and is independent of the total permeabilization achieved by the pulse. Our results, supported by similar measurements on osmotically dehydrated control samples, clearly show that PEF causes a rapid change of the viscoelastic properties of the tissue that could be attributed to a partial loss in turgor pressure. This would be an expected consequence of electroporation. The recovery of tan-δ to values similar to those before pulsation strongly suggests recovery of cell membrane properties and turgor, pointing at reversible permeabilization of the cells. A slight increase of stiffness traduced by a negative change of tan-δ after application of certain PEF conditions may also give an indication of events occurring on cell wall structure due to stress responses. This study set the basis for further investigations on the complex cell stress physiology involving both cell membrane functional properties and cell wall structure that would influence tissue physical properties upon PEF application.Fundação para a Ciência e a Tecnologia (FCT

    The Spectroscopic Diversity of Type Ia Supernovae

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    We present 2603 spectra of 462 nearby Type Ia supernovae (SN Ia) obtained during 1993-2008 through the Center for Astrophysics Supernova Program. Most of the spectra were obtained with the FAST spectrograph at the FLWO 1.5m telescope and reduced in a consistent manner, making data set well suited for studies of SN Ia spectroscopic diversity. We study the spectroscopic and photometric properties of SN Ia as a function of spectroscopic class using the classification schemes of Branch et al. and Wang et al. The width-luminosity relation appears to be steeper for SN Ia with broader lines. Based on the evolution of the characteristic Si II 6355 line, we propose improved methods for measuring velocity gradients, revealing a larger range than previously suspected, from ~0 to ~400 km/s/day considering the instantaneous velocity decline rate at maximum light. We find a weaker and less significant correlation between Si II velocity and intrinsic B-V color at maximum light than reported by Foley et al., owing to a more comprehensive treatment of uncertainties and host galaxy dust. We study the extent of nuclear burning and report new detections of C II 6580 in 23 early-time spectra. The frequency of C II detections is not higher in SN Ia with bluer colors or narrower light curves, in conflict with the recent results of Thomas et al. Based on nebular spectra of 27 SN Ia, we find no relation between the FWHM of the iron emission feature at ~4700 A and Dm15(B) after removing the two low-luminosity SN 1986G and SN 1991bg, suggesting that the peak luminosity is not strongly dependent on the kinetic energy of the explosion for most SN Ia. Finally, we confirm the correlation of velocity shifts in some nebular lines with the intrinsic B-V color of SN Ia at maximum light, although several outliers suggest a possible non-monotonic behavior for the largest blueshifts.Comment: 36 pages (emulateapj), 23 figures. Accepted for publication in AJ. Spectroscopic data available at http://www.cfa.harvard.edu/supernova/SNarchive.html . New SNID template set available at http://marwww.in2p3.fr/~blondin/software/snid/index.html . Minor changes from v1 to conform to published versio

    Temperature dependence of the anomalous effective action of fermions in two and four dimensions

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    The temperature dependence of the anomalous sector of the effective action of fermions coupled to external gauge and pseudo-scalar fields is computed at leading order in an expansion in the number of Lorentz indices in two and four dimensions. The calculation preserves chiral symmetry and confirms that a temperature dependence is compatible with axial anomaly saturation. The result checks soft-pions theorems at zero temperature as well as recent results in the literature for the pionic decay amplitude into static photons in the chirally symmetric phase. The case of chiral fermions is also considered.Comment: RevTex, 19 pages, no figures. References adde

    Unusual shock-excited oh maser emission in a young Planetary Nebula

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    © 2016. The American Astronomical Society. All rights reserved. We report on OH maser emission toward G336.644-0.695 (IRAS 16333-4807), which is a H2O maser-emitting Planetary Nebula (PN). We have detected 1612, 1667, and 1720 MHz OH masers at two epochs using the Australia Telescope Compact Array, hereby confirming it as the seventh known case of an OH-maser-emitting PN. This is only the second known PN showing 1720 MHz OH masers after K 3-35 and the only evolved stellar object with 1720 MHz OH masers as the strongest transition. This PN is one of a group of very young PNe. The 1612 MHz and 1667 MHz masers are at a similar velocity to the 22 GHz H2O masers, whereas the 1720 MHz masers show a variable spectrum, with several components spread over a higher velocity range (up to 36 km s-1). We also detect Zeeman splitting in the 1720 MHz transition at two epochs (with field strengths of ~2 to ~10 mG), which suggests the OH emission at 1720 MHz is formed in a magnetized environment. These 1720 MHz OH masers may trace short-lived equatorial ejections during the formation of the PN

    ATCA detections of massive molecular gas reservoirs in dusty, high-z radio galaxies

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    This is an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. © 2016 The Authors. First published online October 27, 2016, available online at doi: 10.1093/mnras/stw2774. Published by Oxford University Press on behalf of the Royal Astronomical Society.Observations using the 7 mm receiver system on the Australia Telescope Compact Array have revealed large reservoirs of molecular gas in two high-redshift radio galaxies: HATLAS J090426.9+015448 (z = 2.37) and HATLAS J140930.4+003803 (z = 2.04). Optically the targets are very faint, and spectroscopy classifies them as narrow-line radio galaxies. In addition to harbouring an active galactic nucleus the targets share many characteristics of sub-mm galaxies. Far-infrared data from Herschel-ATLAS suggest high levels of dust (>10^9 M_solar) and a correspondingly large amount of obscured star formation (~1000 M_solar / yr). The molecular gas is traced via the J = 1-0 transition of 12CO, its luminosity implying total H_2 masses of (1.7 +/- 0.3) x 10^11 and (9.5 +/- 2.4) x 10^10 (alpha_CO/0.8) M_solar in HATLAS J090426.9+015448 and HATLAS J140930.4+003803 respectively. Both galaxies exhibit molecular line emission over a broad (~1000 km/s) velocity range, and feature double-peaked profiles. We interpret this as evidence of either a large rotating disk or an on-going merger. Gas depletion timescales are ~100 Myr. The 1.4 GHz radio luminosities of our targets place them close to the break in the luminosity function. As such they represent `typical' z > 2 radio sources, responsible for the bulk of the energy emitted at radio wavelengths from accretion-powered sources at high redshift, and yet they rank amongst the most massive systems in terms of molecular gas and dust content. We also detect 115 GHz rest-frame continuum emission, indicating a very steep high-radio-frequency spectrum, possibly classifying the targets as compact steep spectrum objects.Peer reviewedFinal Published versio

    Effect of oat β-glucan on glycemic index and glycemic load of a nutritional supplement sweetened with sucralose in healthy adults: A randomized clinical trial

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    Indexación: Scopus; RedalycLas propiedades hipoglicemiantes del β-glucano de avena son de interés para la industria alimentaria y el área clínica, por sus potenciales beneficios sobre la salud al disminuir la respuesta glicémica, el nivel sérico de lipoproteínas de baja densidad y el índice glicémico de los alimentos. Existen suplementos nutricionales específicos para diabéticos edulcorados con sucralosa cuyo índice glicémico y carga glicémica aún no han sido establecidos. El efecto del β-glucano de avena sobre el índice glicémico y carga glicémica de un suplemento nutricional edulcorado con sucralosa, fue determinado en 13 adultos sanos (6 hombres y 7 mujeres), quienes consumieron aleatoriamente 4 alimentos en días distintos, de 50 g de carbohidratos cada uno: suplemento nutricional para diabéticos (FN), suplemento nutricional con β-glucano (FN- β), y como productos de referencia: solución glucosada (SG) y pan blanco (PB). Se midió glicemia en ayunas y post- prandial a los tiempos 15, 30, 45, 60, 90 y 120 min. El área bajo la curva de glicemia resultó más baja para ambas fórmulas (FN) 12697±993, (FN-β) 11584 ±1171, que para los productos de referencia:(SG) 13900±1245, y (PB) 13267 ± 1557. Los valores de índice glicémico (FN) 67,02 ± 5,69, así como la carga glicémica resultaron intermedios y más bajos para el suplemento con β-glucano incorporado (FN –β) 59,8 ± 6,2; sin diferencias en la concentración de insulina, sugiriendo que la adición del β-glucano derivado de la avena reduce la velocidad de absorción intestinal de la glucosa, efecto que podría estudiarse en diabéticos.The hypoglycemic properties of oat β-glucan is of interest for the food industry and clinical area, for potencial health benefits by reducing glycemic response, serum low-density lipoprotein cholesterol, and glycemic index of meals. There are specific nutritional supplements for diabetics sweetened with sucralose whose glycemic index and glycemic load has not been established. Effect of oat β-glucan on glycemic index and glycemic load of a nutritional supplement sweetened with sucralose in healthy adults was determined in 13 healthy subjects (6 men and 7 women) old that consumed randomly 4 meals of 50 g of carbohydrates each in different days: a nutritional supplement for diabetics (FN), the nutritional supplement with β-glucan incorporated (FN-β) and two reference food, glucose solution (SG) and white bread (PB). Fasting and postprandial glycemia was measured at times 15, 30, 45, 60, 90 and 120 min. The area under the glycemia curve was lower for both formulas (FN) 12697±993, (FN-β) 11584 ±1171 than for reference products (SG) 13900±1245, y (PB) 13267 ± 1557. The values of glycemic index (GI) (FN) 67, 02 ± 5,69 and glycemic load were intermediate and more lower for the supplement with β-glucan incorporated (FN –β) 59, 8 ± 6,2, with no difference of insulin concentration . Suggesting that the addition of oat-derived β-glucan reduces the rate of intestinal absorption of glucose. This effect should be studied in diabetic.http://www.redalyc.org/articulo.oa?id=5594990800

    Effect of antioxidants and pH on browning and firmness of minimally processed eggplant

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    Minimal processing of eggplants (Solanum melongena L.) generates a rapid onset of enzymatic browning, tissue softening and water loss that limits their shelf life. The aim of this study was to evaluate the effect of 1% ascorbic acid and 2% calcium ascorbate in aqueous solution at natural pH of the antioxidant (pH 2.6 and 7.8, respectively), or adjusted to pH 5 with generally recognized as safe substances, to maintain the quality of minimally processed eggplant stored at 5 °C for 6 d. Water was used as a control. The colour, firmness, polyphenol oxidase activity, and visual quality was evaluated in the freshly cut fruit at 3 and 6 d of storage. No effect of the treatments on firmness or polyphenol oxidase activity was observed. At 3 d of storage, a correlation was observed between polyphenol oxidase activity and the visual evaluation of the cut product. Samples treated with 2% calcium ascorbate and the rest of the treatments at pH 5 had a lower browning index than those treated with 1% ascorbic acid and the control. At the end of the storage period, the visual quality of the eggplant samples treated with 1% ascorbic acid at pH 5 was evaluated above the marketing limit, whereas those treated with 1% ascorbic acid at pH 2.6 had the lowest quality indicators. An adjustment to pH 5 helps to preserve the luminosity and visual quality of the eggplant, however firmness was not affected by calcium ascorbate or the pH of the medium
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