The Extreme Polarimeter: Design, Performance, First Results & Upgrades

Well over 700 exoplanets have been detected to date. Only a handful of these have been observed directly. Direct observation is extremely challenging due to the small separation and very large contrast involved. Imaging polarimetry offers a way to decrease the contrast between the unpolarized starlight and the light that has become linearly polarized after scattering by circumstellar material. This material can be the dust and debris found in circumstellar disks, but also the atmosphere or surface of an exoplanet. We present the design, calibration approach, polarimetric performance and sample observation results of the Extreme Polarimeter, an imaging polarimeter for the study of circumstellar environments in scattered light at visible wavelengths. The polarimeter uses the beam-exchange technique, in which the two orthogonal polarization states are imaged simultaneously and a polarization modulator swaps the polarization states of the two beams before the next image is taken. The instrument currently operates without the aid of Adaptive Optics. To reduce the effects of atmospheric seeing on the polarimetry, the images are taken at a frame rate of 35 fps, and large numbers of frames are combined to obtain the polarization images. Four successful observing runs have been performed using this instrument at the 4.2 m William Herschel Telescope on La Palma, targeting young stars with protoplanetary disks as well as evolved stars surrounded by dusty envelopes. In terms of fractional polarization, the instrument sensitivity is better than 10^-4. The contrast achieved between the central star and the circumstellar source is of the order 10^-6. We show that our calibration approach yields absolute polarization errors below 1%

Genetic and epigenetic methylation defects and implication of the ERMN gene in autism spectrum disorders

Autism spectrum disorders (ASD) are highly heritable and genetically complex conditions. Although highly penetrant mutations in multiple genes have been identified, they account for the etiology of <1/3 of cases. There is also strong evidence for environmental contribution to ASD, which can be mediated by still poorly explored epigenetic modifications. We searched for methylation changes on blood DNA of 53 male ASD patients and 757 healthy controls using a methylomic array (450K Illumina), correlated the variants with transcriptional alterations in blood RNAseq data, and performed a case-control association study of the relevant findings in a larger cohort (394 cases and 500 controls). We found 700 differentially methylated CpGs, most of them hypomethylated in the ASD group (83.9%), with cis-acting expression changes at 7.6% of locations. Relevant findings included: (1) hypomethylation caused by rare genetic variants (meSNVs) at six loci (ERMN, USP24, METTL21C, PDE10A, STX16 and DBT) significantly associated with ASD (q-value <0.05); and (2) clustered epimutations associated to transcriptional changes in single-ASD patients (n = 4). All meSNVs and clustered epimutations were inherited from unaffected parents. Resequencing of the top candidate genes also revealed a significant load of deleterious mutations affecting ERMN in ASD compared with controls. Our data indicate that inherited methylation alterations detectable in blood DNA, due to either genetic or epigenetic defects, can affect gene expression and contribute to ASD susceptibility most likely in an additive manner, and implicate ERMN as a novel ASD gene

Temperature Effects in the Composition of Metal Halide Perovskite thin Films

Metal halide perovskites have shown to be a structure with great promise as an efficient photovoltaic, but at the same time it is affected by instability problems that degrade their performance. Degradation mechanisms vary with temperature, moisture, oxidation, and energy conversion during light exposure. We study performance loss due to temperature by probing diffusion of elemental composition across the thickness of films produced by spin coating and for temperatures ranging from 20 to 200°C. X-ray reflectivity was used to identify the electron density, composition, and quality of the films, aided with X-ray fluorescence and X-ray photoelectron spectroscopy studies to obtain information about degradation of the organic phase of the films

Spatially resolved X-ray excited optical luminescence

Spatially resolved luminescence distributions in semiconductor heterostructures were investigated by core level excitation using hard X-ray (sub-) microbeams. Compact and mobile XEOL instruments have been developed and well adapted on the hard X-ray beamline ID22 of the European Synchrotron Radiation Facility for different wavelength collection ranges: UV-VIS and NIR. Linked by multimode optical fibers, their special designs provide precise scanning microscopy and allow easy access for multiple detection modes. Based on the hard X-ray microprobe station of ID22, details of the equipments, spectral data and representative examples are briefly described. Data collections from InAs and InGaN quantum heterostructures support the excellent performance of the optical devices. © 2011 Elsevier B.V. All rights reserved.This work was partially supported by the NANOWIRING Marie Curie ITN (EU project No. PITN-GA-2010-265073).Peer Reviewe

Mid-esophagus unresectable cancer treated with a low cost stent. First experience

<p>Abstract</p> <p>Background</p> <p>In the cancer of the esophagus, with recent technologic advances, self-expanding metal stents (SEMS) are at the forefront of the armamentarium for re-establishing luminal patency. Weighed against the numerous advantages of stents are the import conditions and the cost. In light of this, we tested new low cost prostheses having the basic needs and characteristics to aim a significant benefit to poor people having advanced esophageal cancer, in a Brazilian regional public hospital.</p> <p>Methods</p> <p>This initial experience included fifteen patients (eleven men and four women, 55 ± 6.17 years old), presenting esophageal cancer, located at the medium third of the thoracic esophagus, extending for 5.5-8 cm long, not suitable for surgical procedure because they had been staged on fourth grade of the disease, two of them having fistula communicating esophagus to respiratory tree. The stents were placed under endoscopic and fluoroscopic guidance, after attempting an esophageal dilatation. An appropriate covered stent was then deployed, twelve of 10 cm and three of 13 cm in length. A chest X-ray was done 2 h after the procedure and a barium swallow was performed within 12 hours. Seven days and monthly until complete a six month follow-up after the procedure the patients were questioned about presence of pain, regurgitation, heartburn, cough, and their alimentary behavior.</p> <p>Results</p> <p>There were no severe complications and transient mild chest pain resolved until the seventh day after the stent deployment. Chest X-ray demonstrated expansion of the stent in all patients. In 2 cases of fistula, a barium swallow showed its complete sealing. The completion of the proposed follow-up was not achieved in three cases, limited by the patient's death until the third month, due to cancer progression. Recurrent dysphagia to paste food accounted for by tumor overgrowth proximal or distal to the stent and stent migration were not observed in the series.</p> <p>Conclusions</p> <p>The new low cost endoprostheses is effective and forthcoming increased experience and prospective trials including questionnaires to analyze quality of life will allow for more informed decisions tailoring to a particular patient situation or to unexpected complications.</p

Neoadjuvant Treatment for Resectable and Borderline Resectable Pancreatic Cancer:Chemotherapy or Chemoradiotherapy?

Worldwide, there is a shifting paradigm from immediate surgery with adjuvant treatment to a neoadjuvant approach for patients with resectable or borderline resectable pancreatic cancer (RPC or BRPC). Comparison of neoadjuvant and adjuvant studies is extremely difficult because of a great difference in patient selection. The evidence from randomized studies shows that overall survival by intention-to-treat improves after neoadjuvant gemcitabine-based chemoradiotherapy or chemotherapy (various regimens), as compared to immediate surgery followed by adjuvant chemotherapy. Radiotherapy appears to play an important role in mediating locoregional effects. Yet, since more effective chemotherapy regimens are currently available, in particular FOLFIRINOX and Gemcitabine/Nab-paclitaxel, these chemotherapy regimens should be investigated in future randomized trials combined with (stereotactic) radiotherapy to further improve outcomes of RPC and BRPC

Patrimoni cultural i educació: algunes reflexions didàctiques a la llum dels resultats d’una investigació de camp a les illes balears

Aquesta ponència és fruit del treball de camp desenvolupat al llarg del curs acadèmic 2003/2004 sobre la incidència del patrimoni cultural de les Illes Balears a l’escola (amb especial referència a Mallorca). A la llum dels resultats de la nostra investigació, hem de dir que la qüestió patrimonial té una escassa repercussió en l' ámbit escolar i, no obstant això, o precissament per això, creiem que és necessari aportar informació al professorat sobre la qüestió per tal d’animar els professionals i engrescar-los en la tasca d’usar un dels recursos amb més possibilitats didáctiques i metodològiques que tenen al seu abast. D'altra banda, investigacions d'aquest tipus en altres autonomies podrien donar com resultat una base de dades sobre el patrimoni que integrés totes les publicacions culturals de tots els municipis espanyols, la qual cosa seria de gran utilitat, no sols des d'una perspectiva pedagògica, sinó també cultural, perquè, sens dubte, una base d’aquestes característiques podria ser aprofitada, no sols pels docents, sinó també pels investigadors i visitants i, en general, per qualsevol persona interessada en la temática.Eje: Educación primaria. ReflexionesRed de Universidades con Carreras en Informática (RedUNCI

Patrimoni cultural i educació: algunes reflexions didàctiques a la llum dels resultats d’una investigació de camp a les illes balears

Aquesta ponència és fruit del treball de camp desenvolupat al llarg del curs acadèmic 2003/2004 sobre la incidència del patrimoni cultural de les Illes Balears a l’escola (amb especial referència a Mallorca). A la llum dels resultats de la nostra investigació, hem de dir que la qüestió patrimonial té una escassa repercussió en l' ámbit escolar i, no obstant això, o precissament per això, creiem que és necessari aportar informació al professorat sobre la qüestió per tal d’animar els professionals i engrescar-los en la tasca d’usar un dels recursos amb més possibilitats didáctiques i metodològiques que tenen al seu abast. D'altra banda, investigacions d'aquest tipus en altres autonomies podrien donar com resultat una base de dades sobre el patrimoni que integrés totes les publicacions culturals de tots els municipis espanyols, la qual cosa seria de gran utilitat, no sols des d'una perspectiva pedagògica, sinó també cultural, perquè, sens dubte, una base d’aquestes característiques podria ser aprofitada, no sols pels docents, sinó també pels investigadors i visitants i, en general, per qualsevol persona interessada en la temática.Eje: Educación primaria. ReflexionesRed de Universidades con Carreras en Informática (RedUNCI

Hot Photoluminescence in γ-In2Se3Nanorods

The energy relaxation of electrons in γ-In2Se3nanorods was investigated by the excitation-dependent photoluminescence (PL). From the high-energy tail of PL, we determine the electron temperature (Te) of the hot electrons. TheTevariation can be explained by a model in which the longitudinal optical (LO)-phonon emission is the dominant energy relaxation process. The high-quality γ-In2Se3nanorods may be a promising material for the photovoltaic devices