848 research outputs found

    EXCITATION of COUPLED STELLAR MOTIONS in the GALACTIC DISK by ORBITING SATELLITES

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    We use a set of high-resolution N-body simulations of the Galactic disk to study its interactions with the population of cosmologically predicted satellites. One simulation illustrates that multiple passages of massive satellites with different velocities through the disk generate a wobble, which has the appearance of rings in face-on projections of the stellar disk. They also produce flares in the outer disk parts and gradually heat the disk through bending waves. A different numerical experiment shows that an individual satellite as massive as the Sagittarius dwarf galaxy passing through the disk will drive coupled horizontal and vertical oscillations of stars in underdense regions with small associated heating. This experiment shows that vertical excursions of stars in these low-density regions can exceed 1 kpc in the Solar neighborhood, resembling the recently locally detected coherent vertical oscillations. They can also induce non-zero vertical streaming motions as large as 10-20 km s-1, which is consistent with recent observations in the Galactic disk. This phenomenon appears as a local ring with modest associated disk heating. © 2016. The American Astronomical Society. All rights reserved

    Thermal noise limit in the Virgo mirror suspension

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    Abstract The expected current limit to the Virgo sensitivity is presented. New materials to realize a low thermal noise suspension for the Virgo optics are investigated. A promising fused silica suspension for the Virgo mirrors is presented

    A parallel Beowulf-based system for the detection of gravitational waves in interferometric detectors

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    The detection, in a modern interferometric detector like Virgo, of a gravitational wave signal from a coalescing binary stellar system is an intensive computational task both for the on-line and off-line computer systems. A parallel computing scheme using the Message Passing Interface (MPI) is described. Performance results on a small scale cluster are reported

    Interacting dark matter contribution to the Galactic 511 keV gamma ray emission: constraining the morphology with INTEGRAL/SPI observations

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    We compare the full-sky morphology of the 511 keV gamma ray excess measured by the INTEGRAL/SPI experiment to predictions of models based on dark matter (DM) scatterings that produce low-energy positrons: either MeV-scale DM that annihilates directly into e+e- pairs, or heavy DM that inelastically scatters into an excited state (XDM) followed by decay into e+e- and the ground state.By direct comparison to the data, we find that such explanations are consistent with dark matter halo profiles predicted by numerical many-body simulations for a Milky Way-like galaxy. Our results favor an Einasto profile over the cuspier NFW distribution and exclude decaying dark matter scenarios whose predicted spatial distribution is too broad. We obtain a good fit to the shape of the signal using six fewer degrees of freedom than previous empirical fits to the 511 keV data. We find that the ratio of flux at Earth from the galactic bulge to that of the disk is between 1.9 and 2.4, taking into account that 73% of the disk contribution may be attributed to the beta decay of radioactive 26Al.Comment: 7 pages, 4 figures. Includes minor corrections, and a discussion of threshold energies in XDM models. Published in JCA

    Emergency Department as an epidemiological observatory of Human Mobility: the experience of the Moroccan population

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    We conducted a retrospective study of the accesses to the Emergency Department registered from January 2000 to December 2014 in 5 major hospitals in the Metropolitan Area of Rome. We extrapolated data relating to patients of Moroccan origin from about 5 million total accesses, so we compared with Italians data which, in the same period, came to ED. The Moroccan population is distinguished by a larger number of diagnoses belonging to the ICD-9 code of Infectious Diseases and, more precisely, to Respiratory Infectious Diseases. There are also no differences in the assignment of such diagnoses to Moroccans with Italian citizenship, and this led to think that this could play an important role in the use of the ED and moreover that enrollment to the National Health Service may reduce its inappropriate use. Regarding to Degenerative Disorders, the result of our analysis is quite emblematic, showing that the accesses to the ED is due to Cardiovascular Diseases: 6.33% of Italians' accesses against 1.81% of Moroccans and 2.36% of Moroccans with Italian citizenship. The main explanation for this difference is, obviously, due to the age of the population: about 60% of Moroccans who accessed to ED was less than 40 years old. It is interesting how, in the field of ​​Cardiovascular Diseases, Moroccans have a lower percentage of diagnosis compared to Italians for acute diseases and a greater percentage of diagnoses for chronic diseases, suggesting once again that accesses to ED for migrants often is due to the inability to use the general services of the National Health Service. In conclusion, from the point of view of the Emergency Department, Migration Medicine still has Infectious Diseases as the main reason for access. Degenerative Disorders remain a prerogative of the Italians, but we could certainly assume that the Moroccan population would develop at some point with the aging

    On the classification of OADP varieties

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    The main purpose of this paper is to show that OADP varieties stand at an important crossroad of various main streets in different disciplines like projective geometry, birational geometry and algebra. This is a good reason for studying and classifying them. Main specific results are: (a) the classification of all OADP surfaces (regardless to their smoothness); (b) the classification of a relevant class of normal OADP varieties of any dimension, which includes interesting examples like lagrangian grassmannians. Following [PR], the equivalence of the classification in (b) with the one of quadro-quadric Cremona transformations and of complex, unitary, cubic Jordan algebras are explained.Comment: 13 pages. Dedicated to Fabrizio Catanese on the occasion of his 60th birthday. To appear in a special issue of Science in China Series A: Mathematic

    Antenatal intervention for congenital fetal lower urinary tract obstruction (LUTO): a systematic review and meta-analysis.

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    To evaluate the effectiveness of antenatal intervention for the treatment of congenital lower urinary tract obstruction (LUTO) in improving perinatal survival and postnatal renal function. METHODS: Electronic databases were searched from their inception until May 2018. Selection criteria included randomized controlled trials and controlled nonrandomized observational studies including fetuses with ultrasound evidence of LUTO evaluating antenatal intervention for improving perinatal outcomes. Any type of intervention was analyzed. The primary outcome was perinatal survival. The secondary outcome was postnatal survival with normal renal function. The summary measures were reported as summary odds ratio (OR) with 95% of confidence interval (CI). RESULTS: Ten articles with a total of 355 fetuses were included in the meta-analysis. Inclusion criteria of the selected studies were singleton pregnancy with severe LUTO confirmed on detailed fetal ultrasound examination. Nine studies, analyzed the efficacy of vesico-amniotic shunt performed in the second trimester. The overall estimate survival was higher in the vesico-amniotic shunt group compared to the conservative group (OR 2.54, 95% CI 1.14-5.67). 64/112 fetuses (57.1%) survived in the vesico-amniotic shunt group compared to 52/134 (38.8%) in the control group. Five studies reported on postnatal renal function between 6 months and 2 years. Postnatal renal function was higher in the vesico-amniotic shunt group compared to the conservative group (OR 2.09, 95% CI 0.74-5.9). Fetal cystoscopy was performed in only two included studies. Overall, 45 fetuses underwent fetal cystoscopy. The perinatal survival was higher in the cystoscopy group compared to the conservative management group (OR 2.63, 95% CI 1.07-6.47). Normal renal function was noted in 13/34 fetuses in the cystoscopy group versus 12/61 in the conservative management group at 6 months follow-up (OR 1.75, 95% CI 1.05-2.92) Conclusions: Antenatal bladder drainage appears to improve perinatal survival in cases of LUTO. Further randomized trials with long-term follow-up are required to determine the role of antenatal treatment in clinical setting

    Phosphorylation-regulated degradation of the tumor-suppressor form of PED by chaperone-mediated autophagy in lung cancer cells

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    PED/PEA-15 is a death effector domain (DED) family member with a variety of effects on cell growth and metabolism. To get further insight into the role of PED in cancer, we aimed to find new PED interactors. Using tandem affinity purification, we identified HSC70 (Heat Shock Cognate Protein of 70kDa)-which, among other processes, is involved in chaperone-mediated autophagy (CMA)-as a PED-interacting protein. We found that PED has two CMA-like motifs (i.e., KFERQ), one of which is located within a phosphorylation site, and demonstrate that PED is a bona fide CMA substrate and the first example in which phosphorylation modifies the ability of HSC70 to access KFERQ-like motifs and target the protein for lysosomal degradation. Phosphorylation of PED switches its function from tumor suppression to tumor promotion, and we show that HSC70 preferentially targets the unphosphorylated form of PED to CMA. Therefore, we propose that the up-regulated CMA activity characteristic of most types of cancer cell enhances oncogenesis by shifting the balance of PED function toward tumor promotion. This mechanism is consistent with the notion of a therapeutic potential for targeting CMA in cancer, as inhibition of this autophagic pathway may help restore a physiological ratio of PED form

    Requerimiento de proteĂ­na en juveniles del pez marino chita Anisotremus scapularis (Tschudi, 1846) (Perciformes: Haemulidae)

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    The present study was carried out to determine the protein requirement in Peruvian grunt juvenile, Anisotremus scapularis. In total, 72 fish weighing 19.95 ± 4.09 g and length of 10.31 ± 0.63 cm were used. They were randomly distributed in groups of six units per tank. The experimental diets contained protein levels of 45, 50, 55 and 58%, which were supplied to three experimental units per diet. The fish were fed three times a day to satiety for a period of 56 days. The results showed that final weight, weight gain, feed intake and feed conversion ratio were significantly (p<0.05) affected by dietary protein levels. However, the increase in size and the specific growth rate did not present significant differences (p>0.05) between treatments. The protein requirement based on weight gain using second degree polynomial regression was 56.78%, for optimal growth of Peruvian grunt juveniles.El presente estudio fue realizado para determinar el requerimiento de proteína del alimento en juveniles de Chita, Anisotremus scapularis. Se utilizaron 72 peces con un peso de 19.95 ± 4.09 g y 10.31 ± 0.63 cm de longitud, los cuales fueron distribuidos aleatoriamente en grupos de seis unidades por tanque. Las dietas experimentales contenían niveles de proteína de 45, 50, 55 y 58%, las que fueron suministradas a tres unidades experimentales por dieta. Los peces fueron alimentados tres veces por día hasta la saciedad por un periodo de 56 días. Los resultados mostraron que el peso final, ganancia de peso, consumo de alimento y conversión alimenticia fueron significativamente (p<0.05) afectados por los niveles de proteína en la dieta. Sin embargo, el incremento de longitud y la tasa especifica de crecimiento no presentaron diferencias significativas (p>0.05) entre tratamientos. El requerimiento de proteína determinado en base a la ganancia de peso mediante la regresión polinomial de segundo grado fue de 56.78% para el óptimo crecimiento de juveniles de chita
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