7,145 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
A note on some mathematical models on the effects of Bt-maize exposure
Some mathematical models for the estimation of the effects of Cry1Ab and
Cry1F Bt-maize exposure in the biodiversity are discussed. Novel results about
these models are obtained and described in the note. The exact formula for the
proportion of the population that suffers mortality exposed to Cry1Ab pollen,
underlining its dependence on the margin from the Bt crop edge, is derived. In
addition, regarding Cry1F pollen effects, it is proposed a procedure, using a
probabilistic and statistical approach, that computes the width of the non
Bt-stripes used as mitigation measures. Finally, it has been derived a lower
bound, using probabilistic consideration, on the species sensitivity of
Lepidoptera.Comment: 10 pages, 1 figure. Early draft of a paper accepted for publication
on Environmental and Ecological Statistic
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
Impact of the Rome II paediatric criteria on the appropriateness of the upper and lower gastrointestinal endoscopy in children.
BACKGROUND:
The demand for paediatric gastrointestinal (GI) endoscopy has increased, resulting in a significant rise of overall costs.
AIM:
To assess the clinical impact of the Rome II criteria for functional gastrointestinal disorders when selecting paediatric patients who underwent GI endoscopy.
METHODS:
The indications and findings of GI endoscopic procedures performed before and after the publication of the Rome II criteria were evaluated retrospectively.
RESULTS:
Upper GI endoscopy was performed in 1124 children, whereas colonoscopy was performed in 500 subjects. A total of 607 (54%) oesophago-gastro-duodenoscopies (OGDs) were positive and 517 (46%) were negative, whereas 306 (61.1%) colonoscopies were positive and 194 (38.9%) were negative. Of the 1624 procedures, 26% were considered inappropriate according to the Rome II criteria. Inappropriate procedures decreased significantly after publication of the Rome II criteria (OR, 3.7; 95% CI, 1.8-7.5). Of 1202 appropriate GI endoscopies, 502 OGD (62.7%) were significantly contributive, compared with only 105 (32.5%) of the 323 inappropriate procedures (OR, 3.5; 95% CI, 2.6-4.6), whereas 265 (65.8%) colonoscopies were significantly contributive, compared with only 41 (42.3%) of the 97 inappropriate procedures (OR, 2.6; 95% CI, 1.6-4.1).
CONCLUSIONS:
The use of the criteria for functional gastrointestinal disorders makes a significant positive impact, they should reduce unnecessary paediatric GI endoscopy
Temporal Changes in Energy-Balance Behaviors and Home Factors in Adolescents with Normal Weight and Those with Overweight or Obesity
This study aimed to examine the temporal changes in energy-balance behaviors and home factors in adolescents with normal weight and those with overweight or obesity (OWOB). Adolescents or parent proxies completed survey assessments two to four years before (T0; n = 82), ≤ six months before (T1; n = 68), and ≤ three months after the COVID-19 pandemic outbreak (T2; n = 82), to capture energy-balance behaviors (i.e., physical activity [PA], screen time, sleep) and home factors (i.e., food environment, food worry, parent support for PA). At T0 and T1 (before pandemic), participants visited our laboratory for anthropometric measurements. At T2, parent proxies also completed a survey to report the COVID-19 pandemic exposure and impact. The participating families experienced moderate levels of pandemic exposure and impact, although exposure was higher in the OWOB group (F1,78= 5.50, p \u3c .05). Repeated-measure multivariate analyses of covariance (RM-MACOVAs) did not show significant time by weight status interaction effects (p \u3e 0.05; adjusted for race and sex). However, the models detected significant time (T0 vs. T2) by race (White vs. non-White) interaction effect (λ7,66=0.81, p \u3c 0.05), with greater increase in food worry (F1,72 = 4.36, p \u3c .05) but less increase in screen time (F1,72= 4.54, p \u3c .05) among the non-White group. Graphical visualization depicted some favorable change patterns in adolescents with normal weight (vs. those with OWOB) for certain behaviors and home factors (e.g., number of days per week ≥ 60 mins PA, food worry). These findings suggest that the COVID-19 pandemic exerted greater adverse effects on adolescents with OWOB and specifically on screen time and food worry among non-White adolescents
Impact of antisecretory treatment on respiratory symptoms of gastroesophageal reflux disease in children.
Assessing the effects of Bt maize on the non-target pest Rhopalosiphum maidis by demographic and life-history measurement endpoints
The most commercialized Bt maize plants in Europe were transformed with genes which express a truncated form of the insecticidal delta-endotoxin (Cry1Ab) from the soil bacterium Bacillus thuringiensis (Bt) specifically against Lepidoptera. Studies on the effect of transgenic maize on non-target arthropods have mainly converged on beneficial insects. However, considering the worldwide extensive cultivation of Bt maize, an increased availability of information on their possible impact on non-target pests is also required. In this study, the impact of Bt-maize on the non-target corn leaf aphid, Rhopalosiphum maidis, was examined by comparing biological traits and demographic parameters of two generations of aphids reared on transgenic maize with those on untransformed near-isogenic plants. Furthermore, free and bound phenolics content on transgenic and near-isogenic plants were measured. Here we show an increased performance of the second generation of R. maidis on Bt-maize that could be attributable to indirect effects, such as the reduction of defense against pests due to unintended changes in plant characteristics caused by the insertion of the transgene. Indeed, the comparison of Bt-maize with its corresponding near-isogenic line strongly suggests that the transformation could have induced adverse effects on the biosynthesis and accumulation of free phenolic compounds. In conclusion, even though there is adequate evidence that aphids performed better on Bt-maize than on non-Bt plants, aphid economic damage has not been reported in commercial Bt corn fields in comparison to non-Bt corn fields. Nevertheless, Bt-maize plants can be more easily exploited by R. maidis, possibly due to a lower level of secondary metabolites present in their leaves. The recognition of this mechanism increases our knowledge concerning how insect-resistant genetically modified plants impact on non-target arthropods communities, including tritrophic web interactions, and can help support a sustainable use of genetically modified crops
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