955 research outputs found

    On the Progenitor and Supernova of the SN 2002cx-like Supernova 2008ge

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    We present observations of supernova (SN) 2008ge, which is spectroscopically similar to the peculiar SN 2002cx, and its pre-explosion site that indicate that its progenitor was probably a white dwarf. NGC 1527, the host galaxy of SN 2008ge, is an S0 galaxy with no evidence of star formation or massive stars. Astrometrically matching late-time imaging of SN 2008ge to pre-explosion HST imaging, we constrain the luminosity of the progenitor star. Since SN 2008ge has no indication of hydrogen or helium in its spectrum, its progenitor must have lost its outer layers before exploding, requiring that it be a white dwarf, a Wolf-Rayet star, or a lower-mass star in a binary system. Observations of the host galaxy show no signs of individual massive stars, star clusters, or H II regions at the SN position or anywhere else, making a Wolf-Rayet progenitor unlikely. Late-time spectroscopy of SN 2008ge show strong [Fe II] lines with large velocity widths compared to other members of this class at similar epochs. These previously unseen features indicate that a significant amount of the SN ejecta is Fe (presumably the result of radioactive decay of 56Ni generated in the SN), further supporting a thermonuclear explosion. Placing the observations of SN 2008ge in the context of observations of other objects in the class of SN, we suggest that the progenitor was most likely a white dwarf.Comment: 9 pages, 6 figures, accepted by A

    Single incision laparoscopic anterior resection for cancer using a 'QuadiPort Access System®'

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    BACKGROUND: Single incision laparoscopic surgery (SILS) is developing rapidly and different devices are already available. However there is limited data in the literature about single port laparoscopic colorectal surgery. AIMS: We report the first case of a single incision laparoscopic anterior resection for cancer using the device 'QuadiPort Access System?'. METHODS: A 66 year old female affected by adenocarcinoma of the rectosigmoid junction underwent a radical single incision laparoscopic anterior resection performed by an experienced laparoscopic team. RESULTS: The preoperative staging was T2N0M0. The total operative time was 135 min. Length of hospital stay was 6 days. The length of the specimen was 27 cm and 21 nodes were isolated. The pathological examination showed adenocarcinoma staged T3N2MX; G2. There was no postoperative morbidity and at the 6 month follow-up, the patient presented in well condition with no complications and free from cancer. CONCLUSION: Single incision laparoscopic anterior resection for locally advanced high rectal cancer seems to be feasible and the 'QuadiPort Access System?' seems to be a valid device. To evaluate outcomes and costeffectiveness of SILS versus the standard laparoscopic colorectal surgery multicenter prospective randomised trials are necessary and the 'QuadiPort Access System?' could prove to be the device of choice

    How to promote vaccinations: a pilot study in the North-West of Italy

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    Background: vaccines are one of the greatest medical discoveries. In various countries, pharmacists are authorised to administer vaccines directly in pharmacies; thus, leading to an increase in the immunisation rate and a notable gain in consensus amongst the population. The main objective was to evaluate the opinion of pharmacy customers regarding the proposal to authorise pharmacies to administer vaccines. Results: 85% of the respondents were in favour of the introduction of a vaccinating pharmacist. The data show more positive attitudes to the introduction of this service amongst subjects with an elderly dependant relative (PR = 1,10; p = 0.025). Furthermore, it can be noticed a higher probability of positive attitudes to the establishment of the vaccinating pharmacist amongst those with positive attitudes to vaccines (PR = 1,15; p = 0.039). Moreover, the pharmacist is seen as a reference on the subject of vaccines by only 8% of interviewees. Discussion: The data highlight the particularly positive feedback regarding the subject of pharmacists being authorised to administer vaccines. This service may, however, encounter obstacles such as economic problems and opposition from other health professionals. Materials and methods: Data were gathered through a face-to-face interview by means of questionnaires in eight pharmacies in the north-west of Piedmont (Italy). Descriptive statistics were performed. The comparison between the proportions and average values was performed by χ2 and t-test. The indicator used for the associations was the Prevalence Ratio (PR). The PR was calculated using a modified Poisson regression with robust standard errors. The level of significance was fixed at 0.05; IC at 95%

    Cannabis for Medical Use: Analysis of Recent Clinical Trials in View of Current Legislation

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    Cannabis has long been regarded as a recreational substance in the Western world. The recent marketing authorization of some medicinal products of industrial origin and the introduction onto the market of inflorescences for medical use mean that medical doctors can now prescribe Cannabis-based medicines in those countries which allow it. Nevertheless, there is still considerable controversy on this topic in the scientific community. In particular, this controversy concerns: the plant species to be used; the pathologies that can be treated and consequently the efficacy and safety of use; the routes of administration; the methods of preparation; the type and dosage of cannabinoids to be used; and, the active molecules of interest. As such, although medical Cannabis has been historically used, the results of currently completed and internationally published studies are inconclusive and often discordant. In light of these considerations, the aim of this work is to analyse the current legislation in countries that allow the use of medical Cannabis, in relation to the impact that this legislation has had on clinical trials. First of all, a literature search has been performed (PubMed and SciFinder) on clinical trials which involved the administration of Cannabis for medical use over the last 3 years. Of the numerous studies extrapolated from the literature, only about 43 reported data on clinical trials on medical Cannabis, with these mainly being performed in Australia, Brazil, Canada, Denmark, Germany, Israel, Netherlands, Switzerland, the United Kingdom and the United States of America. Once the reference countries were identified, an evaluation of the legislation in relation to Cannabis for medical use in each was carried out via the consultation of the pertinent scientific literature, but also of official government documentation and that of local regulatory authorities. This analysis provided us with an overview of the different legislation in these countries and, consequently, allowed us to analyse, with greater awareness, the results of the clinical trials published in the last 3 years in order to obtain general interest indications in the prosecution of scientific research in this area

    Laparascopic colon resection for cancer: Evidence based results

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    About 90-92% of patients with carcinoma of the colon are treated surgically. For other surgeons, laparoscopic surgery for the treatment of malignancies remains controversial because of concerns about the adequacy of lymphadenectomy, the extent of resection, early findings of port-site metastasis and the lack of data on long-term results. In our experience, there are no differences between the laparoscopic and laparotomic techniques, and only advantages if the laparoscopic technique is use correctly. We essentially agree with the good results of many studies published in the last ten years, but we are extremely confident that it is necessary to have a good learning curve and a high-volume cases hospital to obtain good results through a laparoscopic approach. So laparoscopic colorectal surgery should be performed only by surgeons who have completed training in this approach and who perform the procedure often enough to maintain a good level of competence

    Optical photometry and spectroscopy of the 1987A-like supernova 2009mw

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    We present optical photometric and spectroscopic observations of the 1987A-like supernova (SN) 2009mw. Our BVRIBVRI and grizg'r'i'z' photometry covers 167 days of evolution, including the rise to the light curve maximum, and ends just after the beginning of the linear tail phase. We compare the observational properties of SN 2009mw with those of other SNe belonging to the same subgroup, and find that it shows similarities to several objects. The physical parameters of the progenitor and the SN are estimated via hydrodynamical modelling, yielding an explosion energy of 11 foe, a pre-SN mass of 19M19\,{\rm M_{\odot}}, a progenitor radius as 30R30\,{\rm R_{\odot}} and a 56^{56}Ni mass as 0.062M0.062\,{\rm M_{\odot}}. These values indicate that the progenitor of SN 2009mw was a blue supergiant star, similar to the progenitor of SN 1987A. We examine the host environment of SN 2009mw and find that it emerged from a population with slightly sub-solar metallicty.Comment: 11 pages, 12 figures, accepted for publication in MNRA

    The High Cadence Transit Survey (HiTS): Compilation and Characterization of Light-curve Catalogs

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    Indexación: Scopus.J.M. acknowledges support from CONICYT-Chile through CONICYT-PCHA/Doctorado-Nacional/2014-21140892. J.M., F.F., G.C.V., and G.M. acknowledge support from the Ministry of Economy, Development, and Tourism’s Millennium Science Initiative through grant IC120009, awarded to the Millennium Institute of Astrophysics (MAS). F.F. acknowledges support from Conicyt through the Fondecyt Initiation into Research project No. 11130228. J.M., F.F., J.S.M., G.C.V., and S.G. acknowledge support from Basal Project PFB-03, Centro de Modelamiento Matemáico (CMM), Universidad de Chile. P.L. acknowledges support by Fondecyt through project #1161184. G.C.V. gratefully acknowledges financial support from CON-ICYT-Chile through FONDECYT postdoctoral grant number 3160747 and CONICYT-Chile and NSF through the Programme of International Cooperation project DPI201400090. P.H. acknowledges support from FONDECYT through grant 1170305. L.G. was supported in part by the US National Science Foundation under grant AST-1311862. G.M. acknowledges support from Conicyt through CONICYT-PCHA/Magís-terNacional/2016-22162353. Support for T.d.J. has been provided by US NSF grant AST-1211916, the TABASGO Foundation, and Gary and Cynthia Bengier. R.R.M. acknowledges partial support from BASAL Project PFB-06, as well as FONDECYT project N◦1170364. Powered@NLHPC: this research was supported by the High Performance Computing infrastructure of the National Laboratory for High Performance Computing (NLHPC), PIA ECM-02, CONICYT. This project used data obtained with the Dark Energy Camera (DECam), which was constructed by the Dark Energy Survey (DES) collaborating institutions: Argonne National Lab, the University of California Santa Cruz, the University of Cambridge, Centro de Investigaciones Energeticas, Medioambientales y Tecnologi-cas-Madrid, the University of Chicago, University College London, the DES-Brazil consortium, the University of Edinburgh, ETH-Zurich, the University of Illinois at Urbana-Champaign, Institut de Ciencies de l’Espai, Institut de Fisica d’Altes Energies, Lawrence Berkeley National Lab, Ludwig-Maximilians Universitat, the University of Michigan, the National Optical Astronomy Observatory, the University of Nottingham, Ohio State University, the University of Pennsylvania, the University of Portsmouth, SLAC National Lab, Stanford University, the University of Sussex, and Texas A&M University. Funding for DES, including DECam, has been provided by the U.S. Department of Energy, National Science Foundation, Ministry of Education and Science (Spain), Science and Technology Facilities Council (UK), Higher Education Funding Council (England), National Center for Supercomputing Applications, Kavli Institute for Cosmological Physics, Financia-dora de Estudos e Projetos, Fundação Carlos Chagas Filho de Amparo a Pesquisa, Conselho Nacional de Desenvolvimento Científico e Tecnológico and the Ministério da Ciência e Tecnologia (Brazil), the German Research Foundation-sponsored cluster of excellence “Origin and Structure of the universe,” and the DES collaborating institutions. Facility: CTIO:1.5 m (DECam).The High Cadence Transient Survey (HiTS) aims to discover and study transient objects with characteristic timescales between hours and days, such as pulsating, eclipsing, and exploding stars. This survey represents a unique laboratory to explore large etendue observations from cadences of about 0.1 days and test new computational tools for the analysis of large data. This work follows a fully data science approach, from the raw data to the analysis and classification of variable sources. We compile a catalog of ∼15 million object detections and a catalog of ∼2.5 million light curves classified by variability. The typical depth of the survey is 24.2, 24.3, 24.1, and 23.8 in the u, g, r, and i bands, respectively. We classified all point-like nonmoving sources by first extracting features from their light curves and then applying a random forest classifier. For the classification, we used a training set constructed using a combination of cross-matched catalogs, visual inspection, transfer/active learning, and data augmentation. The classification model consists of several random forest classifiers organized in a hierarchical scheme. The classifier accuracy estimated on a test set is approximately 97%. In the unlabeled data, 3485 sources were classified as variables, of which 1321 were classified as periodic. Among the periodic classes, we discovered with high confidence one δ Scuti, 39 eclipsing binaries, 48 rotational variables, and 90 RR Lyrae, and for the nonperiodic classes, we discovered one cataclysmic variable, 630 QSOs, and one supernova candidate. The first data release can be accessed in the project archive of HiTS (http://astro.cmm.uchile.cl/HiTS/). © 2018. The American Astronomical Society. All rights reserved.https://iopscience.iop.org/article/10.3847/1538-3881/aadfd

    Ultraviolet Diversity of Type Ia Supernovae

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    Ultraviolet (UV) observations of Type Ia supernovae (SNe Ia) probe the outermost layers of the explosion, and UV spectra of SNe Ia are expected to be extremely sensitive to differences in progenitor composition and the details of the explosion. Here we present the first study of a sample of high signal-to-noise ratio SN Ia spectra that extend blueward of 2900 A. We focus on spectra taken within 5 days of maximum brightness. Our sample of ten SNe Ia spans the majority of the parameter space of SN Ia optical diversity. We find that SNe Ia have significantly more diversity in the UV than in the optical, with the spectral variance continuing to increase with decreasing wavelengths until at least 1800 A (the limit of our data). The majority of the UV variance correlates with optical light-curve shape, while there are no obvious and unique correlations between spectral shape and either ejecta velocity or host-galaxy morphology. Using light-curve shape as the primary variable, we create a UV spectral model for SNe Ia at peak brightness. With the model, we can examine how individual SNe vary relative to expectations based on only their light-curve shape. Doing this, we confirm an excess of flux for SN 2011fe at short wavelengths, consistent with its progenitor having a subsolar metallicity. While most other SNe Ia do not show large deviations from the model, ASASSN-14lp has a deficit of flux at short wavelengths, suggesting that its progenitor was relatively metal rich.Comment: 9 pages, 6 figures, submitted to MNRA
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