6,571 research outputs found
Steps toward a classifier for the Virtual Observatory. I. Classifying the SDSS photometric archive
Modern photometric multiband digital surveys produce large amounts of data
that, in order to be effectively exploited, need automatic tools capable to
extract from photometric data an objective classification. We present here a
new method for classifying objects in large multi-parametric photometric data
bases, consisting of a combination of a clustering algorithm and a cluster
agglomeration tool. The generalization capabilities and the potentialities of
this approach are tested against the complexity of the Sloan Digital Sky Survey
archive, for which an example of application is reported.Comment: To appear in the Proceedings of the "1st Workshop of Astronomy and
Astrophysics for Students" - Naples, 19-20 April 200
Steps towards a map of the nearby universe
We present a new analysis of the Sloan Digital Sky Survey data aimed at
producing a detailed map of the nearby (z < 0.5) universe. Using neural
networks trained on the available spectroscopic base of knowledge we derived
distance estimates for about 30 million galaxies distributed over ca. 8,000 sq.
deg. We also used unsupervised clustering tools developed in the framework of
the VO-Tech project, to investigate the possibility to understand the nature of
each object present in the field and, in particular, to produce a list of
candidate AGNs and QSOs.Comment: 3 pages, 1 figure. To appear in Nucl Phys. B, in the proceedings of
the NOW-2006 (Neutrino Oscillation Workshop - 2006), R. Fogli et al. ed
Media use during adolescence: the recommendations of the Italian Pediatric Society.
BACKGROUND: The use of media device, such as smartphone and tablet, is currently increasing, especially among the youngest. Adolescents spend more and more time with their smartphones consulting social media, mainly Facebook, Instagram and Twitter because. Adolescents often feel the necessity to use a media device as a means to construct a social identity and express themselves. For some children, smartphone ownership starts even sooner as young as 7 yrs, according to internet safety experts. MATERIAL AND METHODS: We analyzed the evidence on media use and its consequences in adolescence. RESULTS: In literature, smartphones and tablets use may negatively influences the psychophysical development of the adolescent, such as learning, sleep and sigh. Moreover, obesity, distraction, addiction, cyberbullism and Hikikomori phenomena are described in adolescents who use media device too frequently. The Italian Pediatric Society provide action-oriented recommendations for families and clinicians to avoid negative outcomes. CONCLUSIONS: Both parents and clinicians should be aware of the widespread phenomenon of media device use among adolescents and try to avoid psychophysical consequences on the youngest
The use of neural networks to probe the structure of the nearby universe
In the framework of the European VO-Tech project, we are implementing new machine learning methods specifically tailored to match the needs of astronomical data mining. In this paper, we shortly present the methods and discuss an application to the Sloan Digital Sky Survey public data set. In particular, we discuss some preliminary results on the 3-D taxonomy of the nearby (z < 0.5) universe. Using neural networks trained on the available spectroscopic base of knowledge we derived distance estimates for ca. 30 million galaxies distributed over 8,000 sq. deg. We also use unsupervised clustering tools to investigate whether it is possible to characterize in broad morphological bins the nature of each object and produce a reliable list of candidate AGNs and QSOs
Impacto social de las radiaciones no ionizantes y las políticas públicas
El objetivo del presente trabajo es fundamentar los beneficios de la contribución del asesoramiento profesional en la generación y transferencia del conocimiento, para la toma de decisiones en las políticas públicas que permita apropiarse de los avances y aplicaciones resultantes del trabajo científico desarrollado.Las Radiaciones No Ionizantes (RNI) son aquellas que no poseen la energía suficiente para ionizar la materia, pero que producen otro tipo de efectos, especialmente de tipo térmico. Sus efectos a largo plazo sobre la salud de los seres humanos aún es materia de discusión y es por esto que se genera en la ciudadanía una honda preocupación por el desconocimiento y falta de normativas a nivel municipal. El Grupo ITMA reúne un grupo interdisciplinario de profesionales con el objetivo de investigar el impacto de las RNI sobre el medio ambiente y los sistemas biológicos. Una de sus actividades es el asesoramiento a municipios y organismos públicos respecto de las RNI, en particular, el despliegue de antenas de telefonía móvil para generar ordenanzas municipales que contribuyan a la tranquilidad y mejora de la calidad de vida de la comunidad y contemplen los controles necesarios para preservar estas condiciones en el tiempo
Association of USF1 and APOA5 polymorphisms with familial combined hyperlipidemia in an Italian population.
Familial combined hyperlipidemia (FCH) is a polygenic and multifactorial disease characterized by a variable phenotype showing increased levels of triglycerides and/or cholesterol. The aim of this study was to identify single nucleotides (SNPs) in lipid-related genes associated with FCH.
METHODS AND RESULTS:
Twenty SNPs in lipid-related genes were studied in 142 control subjects and 165 FCH patients after excluding patients with mutations in the LDLR gene and patients with the E2/E2 genotype of APOE. In particular, we studied the 9996G > A (rs2073658) and 11235C > T (rs3737787) variants in the Upstream Stimulatory Factor 1 gene (USF1), and the -1131T > C (rs662799) and S19W (rs3135506) variants in the Apolipoprotein A-V gene (APOA5). We found that the frequencies of these variants differed between patients and controls and that are associated with different lipid profiles. At multivariate logistic regression SNP S19W in APOA5 remained significantly associated with FCH independently of age, sex, BMI, cholesterol and triglycerides.
CONCLUSIONS:
Our results show that the USF1 and APOA5 polymorphisms are associated with FCH and that the S19W SNP in the APOA5 gene is associated to the disease independently of total cholesterol, triglycerides and BMI. However, more extensive studies including other SNPs such as rs2516839 in USF1, are required
A Practical Guide for the Diagnosis of Primary Enteric Nervous System Disorders
Objective:Primary gastrointestinal neuropathies are a heterogeneous group of enteric nervous system (ENS) disorders that continue to cause difficulties in diagnosis and histological interpretation. Recently, an international working group published guidelines for histological techniques and reporting, along with a classification of gastrointestinal neuromuscular pathology. The aim of this article was to review and summarize the key issues for pediatric gastroenterologists on the diagnostic workup of congenital ENS disorders. In addition, we provide further commentary on the continuing controversies in the field.Results:Although the diagnostic criteria for Hirschsprung disease are well established, those for other forms of dysganglionosis remain ill-defined. Appropriate tissue sampling, handling, and expert interpretation are crucial to maximize diagnostic accuracy and reduce interobserver variability. The absence of validated age-related normal values for neuronal density, along with the lack of correlation between clinical and histological findings, result in significant diagnostic uncertainties while diagnosing quantitative aberrations such as hypoganglionosis or ultrashort Hirschsprung disease. Intestinal neuronal dysplasia remains a histological description of unclear significance.Conclusions:The evaluation of cellular quantitative or qualitative abnormalities of the ENS for clinical diagnosis remains complex. Such analysis should be carried out in laboratories that have the necessary expertise and access to their own validated reference values
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