Light-Trap: A SiPM Upgrade for Very High Energy Astronomy and Beyond

With the development of the Imaging Atmospheric Cherenkov Technique (IACT), Gamma-ray astronomy has become one of the most interesting and productive fields of astrophysics. Current IACT telescope arrays (MAGIC, H.E.S.S, VERITAS) use photomultiplier tubes (PMTs) to detect the optical/near-UV Cherenkov radiation emitted due to the interaction of gamma rays with the atmosphere. For the next generation of IACT experiments, the possibility of replacing the PMTs with Silicon photomultipliers (SiPMs) is being studied. Among the main drawbacks of SiPMs are their limited active area (leading to an increase in the cost and complexity of the camera readout) and their sensitivity to unwanted wavelengths. Here we propose a novel method to build a relatively low-cost pixel consisting of a SiPM attached to a PMMA disc doped with a wavelength shifter. This pixel collects light over a much larger area than a single standard SiPM and improves sensitivity to near-UV light while simultaneously rejecting background. We describe the design of a detector that could also have applications in other fields where detection area and cost are crucial. We present results of simulations and laboratory measurements of a pixel prototype and from field tests performed with a 7-pixel cluster installed in a MAGIC telescope camera.Comment: Proceedings of the 35th International Cosmic Ray Conference (ICRC 2017), Bexco, Busan, Korea. Id:81

Twisting gauged non-linear sigma-models

We consider gauged sigma-models from a Riemann surface into a Kaehler and hamiltonian G-manifold X. The supersymmetric N=2 theory can always be twisted to produce a gauged A-model. This model localizes to the moduli space of solutions of the vortex equations and computes the Hamiltonian Gromov-Witten invariants. When the target is equivariantly Calabi-Yau, i.e. when its first G-equivariant Chern class vanishes, the supersymmetric theory can also be twisted into a gauged B-model. This model localizes to the Kaehler quotient X//G.Comment: 33 pages; v2: small additions, published versio

Analysis of the Adherence and Safety of Second Oral Glucose-Lowering Therapy in Routine Practice From the Mediterranean Area : A Retrospective Cohort Study

Altres ajuts: AstraZeneca/ESR-16-12628Altres ajuts: Applied Research Collaboration East Midlands (ARC EM)Altres ajuts: National Institute for Health Research (NIHR)Altres ajuts: Imperial Biomedical Research Centre (NIHR)The aims of our study was compare adherence measured by the medical possession ratio (MPR), time until discontinuation and describe adverse events after adding a DPP-4i, SGLT-2i, or sulfonylureas (SU) to metformin in a primary care population with insufficient glycemic control. We used routinely-collected health data from the SIDIAP database. The included subjects were matched by propensity score. The follow-up period was up to 24 months or premature discontinuation. The primary outcomes were the percentage of subjects with good adherence, treatment discontinuation and adverse events among treatment groups. The proportion of patients with good adherence (MPR> 0.8) after the addition of DPP-4i, SGLT-2i or SU was 53.6%, 68.7%, and 43.0%, respectively. SGLT-2i users were 1.7 times more likely to achieve good adherence compared with DPP-4i users (odds ratio [OR]:1.72, 98% confidence interval [CI]:1.51, 1.96), and 2.8 times more likely compared with SU users (OR: 0.35, 98% CI: 0.07, 0.29). The discontinuation hazard ratios were 1.43 (98%CI: 1.26; 1.62) and 1.60 (98%CI: 1.42; 1.81) times higher among SGLT-2i and SU users than DPP-4i users during the follow-up period. No differences were observed for adverse events among the treatment groups. In conclusion, in our real-world setting, the combination of SGLT-2i with metformin was associated with better adherence. The mean time until discontinuation was longer in the SGLT-2i group in comparison with the DPP-4i or SU groups

Intersecting Solitons, Amoeba and Tropical Geometry

We study generic intersection (or web) of vortices with instantons inside, which is a 1/4 BPS state in the Higgs phase of five-dimensional N=1 supersymmetric U(Nc) gauge theory on R_t \times (C^\ast)^2 \simeq R^{2,1} \times T^2 with Nf=Nc Higgs scalars in the fundamental representation. In the case of the Abelian-Higgs model (Nf=Nc=1), the intersecting vortex sheets can be beautifully understood in a mathematical framework of amoeba and tropical geometry, and we propose a dictionary relating solitons and gauge theory to amoeba and tropical geometry. A projective shape of vortex sheets is described by the amoeba. Vortex charge density is uniformly distributed among vortex sheets, and negative contribution to instanton charge density is understood as the complex Monge-Ampere measure with respect to a plurisubharmonic function on (C^\ast)^2. The Wilson loops in T^2 are related with derivatives of the Ronkin function. The general form of the Kahler potential and the asymptotic metric of the moduli space of a vortex loop are obtained as a by-product. Our discussion works generally in non-Abelian gauge theories, which suggests a non-Abelian generalization of the amoeba and tropical geometry.Comment: 39 pages, 11 figure

Measurement of the Stray Light in the Advanced Virgo Input Mode Cleaner Cavity using an instrumented baffle

A new instrumented baffle was installed in Spring 2021 at Virgo surrounding the suspended mirror in the input mode cleaner triangular cavity. It serves as a demonstrator of the technology designed to instrument the baffles in the main arms in the near future. We present, for the first time, results on the measured scattered light distribution inside the cavity as determined by the new device using data collected between May and July 2021, with Virgo in commissioning phase and operating with an input laser power in the cavity of 28.5~W. The sensitivity of the baffle is discussed and the data is compared to scattered light simulations.Comment: 4 pages, 5 figures, 1 tabl

Los estudiantes de medicina españoles y la medicina de familia. Datos de las 2 fases de una encuesta estatal

Objetivo Explorar percepciones y expectativas de estudiantes de los cursos 1.°, 3.° y 5.° de las facultades de medicina sobre medicina de familia y comunitaria (MFyC) y atención primaria (AP). Diseño Estudio observacional con administración de un cuestionario en 2 cortes transversales con un intervalo de 2 años. Emplazamiento Facultades de medicina españolas. Participantes Estudiantes de los cursos 1.°, 3.° y 5.° de 22 facultades (1.a fase) y 15 en la segunda. Mediciones principales Cuestionario autocumplimentado administrado durante el primer trimestre de los cursos 2009-2010 y 2011-2012. Consta de 70 ítems en 3 bloques: percepciones sobre MFyC (19 ítems), formación en MFyC (26 ítems), expectativas y preferencias (25 ítems), más 13 ítems específicos para alumnos de 3.° y 5.°. La mayoría se respondían según una escala Likert (de 1 a 6). Resultados En la 1.a fase se obtuvieron 5.299 cuestionarios y 3.869 en la segunda. Los estudiantes perciben la MFyC y AP como un ámbito esencial del sistema sanitario y de ejercicio profesional pero con escaso atractivo científico-técnico. El 87% consideran necesaria y obligatoria la formación en MFyC y que debería iniciarse en el 3.er curso. Prefieren las especialidades médicas hospitalarias (88-89%) seguidas de las quirúrgicas y la pediatría. La MFyC es preferida por el 37-39%. Al iniciar la carrera solamente entre el 24 y el 28% de los estudiantes tienen una decisión clara sobre la especialidad que van a escoger. Conclusiones La MFyC y la AP son ámbitos esenciales y han de formar parte de los currículum pero tienen una baja consideración científica. Objective: To examine the perceptions and expectations about Family Practice (FP) and Primary Care (PC) in 1st, 3rd and 5th year students in medical schools. Design: An observational study in two cross sections with intervals of two years. Location: Spanish Medical Schools. Participants: 1st, 3rd and 5th year students of 22 schools (1st phase) and 15 (second phase). Primary measurements: Self-report questionnaires completed during the first quarter of the 2009-2010 and 2011-2012 academic years. It had 70 items in three blocks: perceptions of FP (19 items), training in FP (26 items), expectations and preferences (25 items), plus 13 specific items for 3rd and 5th year students. Most of the items were answered in a 6 point Likert scale. Results: A total of 5299 responses in phase I, and 3869 in phase II were received. Students perceive FP and PC as essential areas of the health system and professional practice, but with little scientific and technical appeal. The large majortiy, 87%, consider training in FP necessary and compulsory, and it should start in third year. They prefer hospital medical specialities (88-89%), followed by surgical and paediatrics. FP is preferred by the 37-39%. Only between 24% and 28% of students have a clear preference for a specialty when they start medical studies. Conclusions: FP and PC are key areas and should be part of the curriculum, but are perceived to be of low scientific appeal

An instrumented baffle for the Advanced Virgo Input Mode Cleaner End Mirror

A novel instrumented baffle surrounding the suspended end mirror in the input mode cleaner cavity of the Virgo interferometer was installed in spring 2021. Since then, the device has been regularly operated in the experiment and the obtained results indicate a good agreement with simulations of the stray light inside the optical cavity. The baffle will operate in the upcoming O4 observation run, serving as a demonstrator of the technology designed to instrument the baffles in front of the main mirrors in time for O5. In this paper we present a detailed description of the baffle design, including mechanics, front-end electronics, data acquisition, as well as optical and vacuum tests, calibration and installation procedures, and performance results.Comment: 12 pages, 21 figures, 3 tables, to be submitted to PR

Solitons in the Higgs phase -- the moduli matrix approach --

We review our recent work on solitons in the Higgs phase. We use U(N_C) gauge theory with N_F Higgs scalar fields in the fundamental representation, which can be extended to possess eight supercharges. We propose the moduli matrix as a fundamental tool to exhaust all BPS solutions, and to characterize all possible moduli parameters. Moduli spaces of domain walls (kinks) and vortices, which are the only elementary solitons in the Higgs phase, are found in terms of the moduli matrix. Stable monopoles and instantons can exist in the Higgs phase if they are attached by vortices to form composite solitons. The moduli spaces of these composite solitons are also worked out in terms of the moduli matrix. Webs of walls can also be formed with characteristic difference between Abelian and non-Abelian gauge theories. We characterize the total moduli space of these elementary as well as composite solitons. Effective Lagrangians are constructed on walls and vortices in a compact form. We also present several new results on interactions of various solitons, such as monopoles, vortices, and walls. Review parts contain our works on domain walls (hep-th/0404198, hep-th/0405194, hep-th/0412024, hep-th/0503033, hep-th/0505136), vortices (hep-th/0511088, hep-th/0601181), domain wall webs (hep-th/0506135, hep-th/0508241, hep-th/0509127), monopole-vortex-wall systems (hep-th/0405129, hep-th/0501207), instanton-vortex systems (hep-th/0412048), effective Lagrangian on walls and vortices (hep-th/0602289), classification of BPS equations (hep-th/0506257), and Skyrmions (hep-th/0508130).Comment: 89 pages, 33 figures, invited review article to Journal of Physics A: Mathematical and General, v3: typos corrected, references added, the published versio

Investigating silent strokes in hypertensives : a magnetic resonance imaging study (ISSYS): rationale and protocol design

Altres ajuts: This research has been funded with grants from the the Catalonian Society of Hypertension (6th Grant Research in Hypertension).Silent brain infarcts are detected by neuroimaging in up to 20% of asymptomatic patients based on population studies. They are five times more frequent than stroke in general population, and increase significantly both with advancing age and hypertension. Moreover, they are independently associated with the risk of future stroke and cognitive decline. Despite these numbers and the clinical consequences of silent brain infarcts, their prevalence in Mediterranean populations is not well known and their role as predictors of future cerebrovascular and cardiovascular events in hypertensive remains to be determined. ISSYS (Investigating Silent Strokes in Hypertensives: a magnetic resonance imaging study) is an observational cross-sectional and longitudinal study aimed to: 1- determine the prevalence of silent cerebrovascular infarcts in a large cohort of 1000 hypertensives and to study their associated factors and 2-to study their relationship with the risk of future stroke and cognitive decline. Cohort study in a randomly selected sample of 1000 participants, hypertensive aged 50 to 70 years old, with no history of previous stroke or dementia. On baseline all participants will undergo a brain MRI to determine the presence of brain infarcts and other cerebrovascular lesions (brain microbleeds, white matter changes and enlarged perivascular spaces) and will be also tested to determine other than brain organ damage (heart-left ventricular hypertrophy, kidney-urine albumin to creatinine ratio, vessels-pulse wave velocity, ankle brachial index), in order to establish the contribution of other subclinical conditions to the risk of further vascular events. Several sub-studies assessing the role of 24 hour ambulatory BP monitoring and plasma or genetic biomarkers will be performed. Follow-up will last for at least 3 years, to assess the rate of further stroke/transient ischemic attack, other cardiovascular events and cognitive decline, and their predictors. Improving the knowledge on the frequency and determinants of these lesions in our setting might help in the future to optimize treatments or establish new preventive strategies to minimize clinical and socioeconomic consequences of stroke and cognitive decline

Bottom-up engineering of InAs at the nanoscale: From V-shaped nanomembranes to nanowires

The ability to rationally tune the morphology of nanostructures is a fundamental milestone in nanoscale engineering. In particular, the possibility to switch between different shapes within the same material system represents a further step in the development of complex nanoscale devices and it increases the potential of nanostructures in practical applications. We recently reported a new form of InAs nanostructures growing epitaxially on Si substrates as vertical V-shaped membranes. Here we demonstrate the possibility of modifying the shape of these nanomembranes and turning them into nanowires by modulating the surface roughness of the substrate by varying the surface treatment. We show that the growth of nanomembranes is favored on smooth surfaces. Conversely rough surfaces enhance the growth of nanowires. We also shove that the V/III ratio plays a key role in determining the absolute yield, i.e. how many nanostructures form during growth. These results envisage a new degree of freedom in the engineering of bottom up nanostructures and contribute to the achievement of nanostructure networks. (C) 2015 Elsevier B.V. All rights reserved