4,252 research outputs found
Bayesian P-Splines to investigate the impact of covariates on Multiple Sclerosis clinical course
This paper aims at proposing suitable statistical tools to address heterogeneity in repeated measures, within a Multiple Sclerosis (MS) longitudinal study. Indeed, due to unobservable sources of heterogeneity, modelling the effect of covariates on MS severity evolves as a very difficult feature. Bayesian P-Splines are suggested for modelling non linear smooth effects of covariates within generalized additive models. Thus, based on a pooled MS data set, we show how extending Bayesian P-splines to mixed effects models (Lang and Brezger, 2001), represents an attractive statistical approach to investigate the role of prognostic factors in affecting individual change in disability
Graphical chain models for the analysis of complex genetic diseases: an application to hypertension
A crucial task in modern genetic medicine is the understanding of complex genetic diseases. The main complicating features are that a combination of genetic and environmental risk factors is involved, and the phenotype of interest may be complex. Traditional statistical techniques based on lod-scores fail when the disease is no longer monogenic and the underlying disease transmission model is not defined. Different kinds of association tests have been proved to be an appropriate and powerful statistical tool to detect a candidate gene for a complex disorder. However, statistical techniques able to investigate direct and indirect influences among phenotypes, genotypes and environmental risk factors, are required to analyse the association structure of complex diseases. In this paper we propose graphical models as a natural tool to analyse the multifactorial structure of complex genetic diseases. An application of this model to primary hypertension data set is illustrated
Locomotory Adaptations in 3D Humerus Geometry of Xenarthra: Testing for Convergence
Three-dimensional (3D) models of fossil bones are increasingly available, thus opening a novel frontier in the study of organismal size and shape evolution. We provide an example of how photogrammetry can be combined with Geometric Morphometrics (GMM) techniques to study patterns of morphological convergence in the mammalian group of Xenarthra. Xenarthrans are currently represented by armadillos, sloths, and anteaters. However, this clade shows an incredibly diverse array of species and ecomorphotypes in the fossil record, including gigantic ground sloths and glyptodonts. Since the humerus is a weight-bearing bone in quadrupedal mammals and its morphology correlates with locomotor behavior, it provides an ideal bone to gain insight into adaptations of fossil species. A 3D sample of humerii belonging to extant and fossil Xenarthra allowed us to identify a significant phylogenetic signal and a strong allometric component in the humerus shape. Although no rate shift in the evolution of the humerus shape was recorded for any clade, fossorial and arboreal species humerii did evolve at significantly slower and faster paces, respectively, than the rest of the Xenarthran species. Significant evidence for morphological convergence found among the fossorial species and between the two tree sloth genera explains these patterns. These results suggest that the highly specialized morphologies of digging taxa and tree sloths represent major deviations from the plesiomorphic Xenarthran body plan, evolved several times during the history of the group
The use of IASI data to identify systematic errors in the ECMWF forecasts of temperature in the upper stratosphere
Since data from the Infrared Atmospheric Sounding Interferometer (IASI) became available in 2007, a number of papers have appeared in the literature which have reported relatively large discrepancies between IASI spectra and forward calculations in the centre of the CO<sub>2</sub> Q-branch at 667 cm<sup>â1</sup>. In this paper we show that these discrepancies are primarily due to errors in the temperature profiles used in the forward calculations. In particular, we have used forecasts of temperature profiles from the European Centre for Medium-Range Weather Forecasts (ECMWF) to demonstrate that, for the case study considered in this paper, these profiles are affected by systematic errors of the order of â10 K at the level of the stratopause. To derive the magnitude and the spatial location of the systematic errors in the temperature profile, we have carried out forward/inverse calculations for a number of clear-sky, daytime, IASI tropical soundings over the sea. The forward calculations have been performed using atmospheric state vectors which have been obtained either from the direct inversion of the IASI radiances or from space-time co-located profiles derived from radiosonde observations and from the ECMWF model. To rule out any effect due to the accuracy of the forward model, we have performed the forward calculations using two independent models. The sensitivity of the temperature biases to the variability of the CO<sub>2</sub> profile and to spectroscopy errors has also been studied
New trends in teacher\u2019s education. Educational placement of the adopted child
In Italy, the number of adopted school-age children is increasing. According to the Commission of Intercountry Adoption (2013),
3106 children were adopted, 47.5% of them are between 5 and 9 years old. The present action-research aims at exploring the
spread of good approaches in schools in terms of welcoming of adopted children. For this purpose, 268 teachers of primary
schools were involved in analyzing the social representation about adopted children and their family. The results show a
simplified vision of the adoptive family, which is described as heroic family or, on the contrary, as a family with difficulty
How to Commission, Operate and Maintain a Large Future Accelerator Complex from Far Remote
A study on future large accelerators [1] has considered a facility, which is
designed, built and operated by a worldwide collaboration of equal partner
institutions, and which is remote from most of these institutions. The full
range of operation was considered including commi-ssioning, machine
development, maintenance, trouble shooting and repair. Experience from existing
accele-rators confirms that most of these activities are already performed
'remotely'. The large high-energy physics ex-periments and astronomy projects,
already involve inter-national collaborations of distant institutions. Based on
this experience, the prospects for a machine operated remotely from far sites
are encouraging. Experts from each laboratory would remain at their home
institution but continue to participate in the operation of the machine after
construction. Experts are required to be on site only during initial
commissioning and for par-ticularly difficult problems. Repairs require an
on-site non-expert maintenance crew. Most of the interventions can be made
without an expert and many of the rest resolved with remote assistance. There
appears to be no technical obstacle to controlling an accelerator from a
distance. The major challenge is to solve the complex management and
communication problems.Comment: ICALEPCS 2001 abstract ID No. FRBI001 invited talk submitting author
F. Willeke 5 pages, 1 figur
Comments on "Blockade of angiogenesis by small molecule antagonists to protease-activated receptor-1: association with endothelial cell growth suppression and induction of apoptosis".
Monitoraggio geodetico dellâarea vulcanica napoletana: risultati della livellazione geometrica di precisione eseguita ai Campi Flegrei a settembre 2008
Lo studio ed ilmonitoraggio deimovimenti verticali del suolo ai Campi Flegrei (Italy) sono effettuati con
continuitĂ da oltre 30 anni, operando su linee di livellazioni preesistenti istituite e/o ampliate da vari Enti
a partire dal 1905 (IGM, Genio Civile e lo stesso INGV- NA Oss. Vesuviano).
Attraverso i dati rilevati dal 1970 ad oggi sono state acquisite molte informazioni sulla deformazione del
suolo durante le varie fasi di bradisismo discendente e ascendente ed attualmente si dispone di un importante
data-base che puĂČ essere integrato con i risultati ottenuti dalle altre metodologie geodetiche.
In questa nota presentiamo i risultati della campagna di livellazione geometrica di precisione eseguita su alcuni
tratti della rete altimetrica dei Campi Flegrei nel Settembre 2008.
Dopo la fase di lento sollevamento, iniziata nel 2004 e culminata alla fine del 2006 con un valore massimo di
55 mm rilevato a Pozzuoli (Lungomare Pertini) al caposaldo n. 23, nellâarea flegrea Ăš ripresa una fase di lenta
subsidenza caratterizzata da una evidente decelerazione durante il 2008 rispetto allâanno precedente.
Per delineare meglio e dettagliare lâattuale fase del bradisismo flegreo, si Ăš ritenuto utile effettuare il confronto
tra i dati altimetrici acquisiti nelle ultime 3 campagne (2006, 2007 e 2008) da cui Ăš emersa una evidente
disomogeneitĂ del campo di spostamento verticale osservato
Melatonin and phytomelatonin: Chemistry, biosynthesis, metabolism, distribution and bioactivity in plants and animalsâan overview
, Abstract: Melatonin is a ubiquitous indolamine, largely investigated for its key role in the regulation of several physiological processes in both animals and plants. In the last century, it was reported that this molecule may be produced in high concentrations by several species belonging to the plant kingdom and stored in specialized tissues. In this review, the main information related to the chemistry of melatonin and its metabolism has been summarized. Furthermore, the biosynthetic pathway characteristics of animal and plant cells have been compared, and the main differences between the two systems highlighted. Additionally, in order to investigate the distribution of this indolamine in the plant kingdom, distribution cluster analysis was performed using a database composed by 47 previously published articles reporting the content of melatonin in different plant families, species and tissues. Finally, the potential pharmacological and biostimulant benefits derived from the administration of exogenous melatonin on animals or plants via the intake of dietary supplements or the application of biostimulant formulation have been largely discussed
- âŠ