Backward Clusters, Hierarchy and Wild Sums for a Hard Sphere System in a Low-Density Regime

We study the statistics of backward clusters in a gas of hard spheres at low density. A backward cluster is defined as the group of particles involved directly or indirectly in the backwards-in-time dynamics of a given tagged sphere. We derive upper and lower bounds on the average size of clusters by using the theory of the homogeneous Boltzmann equation combined with suitable hierarchical expansions. These representations are known in the easier context of Maxwellian molecules (Wild sums). We test our results with a numerical experiment based on molecular dynamics simulations

A cytological study of four Sicilian Serapias (Orchidaceae)

Cytological analysis of four Serapias L. (Orchidaceae), of which two are Sicilian endemics, is carried out. In particular, the endemic S. intermedia subsp. hyblaea shows a triploid chromosome complement with 2n = 3x = 54, representing natural nothotaxa arising from a hybridization process between supposed parental S. vomeracea (2n = 2x = 36) and Serapias lingua (2n = 4x = 72). For each of them the C-heterochromatin distribution, using Giemsa C-banding and karyotypes, was examined. The other endemic taxon (S. orientalis subsp. siciliensis) is characterized by a diploid chromosome number 2n = 2x = 36, of which the C-heterochromatin distribution is examined as well. The taxonomical relationships among these taxa are discussed in relation to the literature data

Development and Initial Validation of a Questionnaire to Measure Health-Related Quality of Life of Adults with Common Variable Immune Deficiency: The CVID_QoL Questionnaire.

BACKGROUND: Generic health status quality of life (QoL) instruments have been used in patients with common variable immune deficiency (CVID). However, by their nature, these tools may over- or underestimate the impact of diseases on an individual's QoL. OBJECTIVE: The objective of this study was to develop and validate a questionnaire to measure specific-health-related QoL for adults with CVID (CVID_QoL). METHODS: The 32-item content of the CVID_QoL questionnaire was developed using focus groups and individual patient interviews. Validation studies included 118 adults with CVID who completed Short Form-36, Saint George Respiratory Questionnaire, General Health Questionnaire-12, and EuroQol-5D questionnaire in a single session. Principal component and factor analysis solutions identified 3 scores to be similar in number and content for each solution. Validation of 3 factor scores was performed by construct validity. Reproducibility, reliability, convergent validity, and discriminant validity were evaluated. Matrices consisting of correlations between the 32 items in the CVID_QOL were calculated. RESULTS: Factor analysis identified 3 dimensions: emotional functioning (EF), relational functioning (RF), and gastrointestinal and skin symptoms (GSS). The instrument had good internal consistency (Cronbach's alpha, min. 0.74 for GSS, max. 0.84 for RF, n = 118) and high reproducibility (intraclass correlation coefficient, min. 0.79 for RF, max 0.90 for EF, n = 27). EF and RF scores showed good convergent validity correlating with conceptually similar dimensions of other study scales. Acute and relapsing infections had a significant impact on EF and RF. CONCLUSIONS: This study provides evidence of the reliability and construct validity of the CVID_QoL to identify QoL issues in patients with CVID that may not be addressed by generic instruments

The Cauchy problem for the 3-D Vlasov-Poisson system with point charges

In this paper we establish global existence and uniqueness of the solution to the three-dimensional Vlasov-Poisson system in presence of point charges in case of repulsive interaction. The present analysis extends an analogeous two-dimensional result by Caprino and Marchioro [On the plasma-charge model, to appear in Kinetic and Related Models (2010)].Comment: 28 page

KAOS: A new automated computational method for the identification of overexpressed genes

Background: Kinase over-expression and activation as a consequence of gene amplification or gene fusion events is a well-known mechanism of tumorigenesis. The search for novel rearrangements of kinases or other druggable genes may contribute to understanding the biology of cancerogenesis, as well as lead to the identification of new candidate targets for drug discovery. However this requires the ability to query large datasets to identify rare events occurring in very small fractions (1-3 %) of different tumor subtypes. This task is different from what is normally done by conventional tools that are able to find genes differentially expressed between two experimental conditions. Results: We propose a computational method aimed at the automatic identification of genes which are selectively over-expressed in a very small fraction of samples within a specific tissue. The method does not require a healthy counterpart or a reference sample for the analysis and can be therefore applied also to transcriptional data generated from cell lines. In our implementation the tool can use gene-expression data from microarray experiments, as well as data generated by RNASeq technologies. Conclusions: The method was implemented as a publicly available, user-friendly tool called KAOS (Kinase Automatic Outliers Search). The tool enables the automatic execution of iterative searches for the identification of extreme outliers and for the graphical visualization of the results. Filters can be applied to select the most significant outliers. The performance of the tool was evaluated using a synthetic dataset and compared to state-of-the-art tools. KAOS performs particularly well in detecting genes that are overexpressed in few samples or when an extreme outlier stands out on a high variable expression background. To validate the method on real case studies, we used publicly available tumor cell line microarray data, and we were able to identify genes which are known to be overexpressed in specific samples, as well as novel ones

Potential of high-resolution detection and retrieval of precipitation fields from X-band spaceborne synthetic aperture radar over land

Abstract. X-band Synthetic Aperture Radars (X-SARs), able to image the Earth's surface at metric resolution, may provide a unique opportunity to measure rainfall over land with spatial resolution of about few hundred meters, due to the atmospheric moving-target degradation effects. This capability has become very appealing due to the recent launch of several X-SAR satellites, even though several remote sensing issues are still open. This work is devoted to: (i) explore the potential of X-band high-resolution detection and retrieval of rainfall fields from space using X-SAR signal backscattering amplitude and interferometric phase; (ii) evaluate the effects of spatial resolution degradation by precipitation and inhomogeneous beam filling when comparing to other satellite-based sensors. Our X-SAR analysis of precipitation effects has been carried out using both a TerraSAR-X (TSX) case study of Hurricane "Gustav" in 2008 over Mississippi (USA) and a COSMO-SkyMed (CSK) X-SAR case study of orographic rainfall over Central Italy in 2009. For the TSX case study the near-surface rain rate has been retrieved from the normalized radar cross section by means of a modified regression empirical algorithm (MREA). A relatively simple method to account for the geometric effect of X-SAR observation on estimated rainfall rate and first-order volumetric effects has been developed and applied. The TSX-retrieved rain fields have been compared to those estimated from the Next Generation Weather Radar (NEXRAD) in Mobile (AL, USA). The rainfall detection capability of X-SAR has been tested on the CSK case study using the repeat-pass coherence response and qualitatively comparing its signature with ground-based Mt. Midia C-band radar in central Italy. A numerical simulator to represent the effect of the spatial resolution and the antenna pattern of TRMM satellite Precipitation Radar (PR) and Microwave Imager (TMI), using high-resolution TSX-retrieved rain images, has been also set up in order to evaluate the rainfall beam filling phenomenon. As expected, the spatial average can modify the statistics of the high-resolution precipitation fields, strongly reducing its dynamics in a way non-linearly dependent on the rain rate local average value

Physiological and driving behaviour changes associated to different road intersections

Road traffic injuries claim more than 1.2 million lives each year in the world and have a huge impact on health and development. It is commonly acknowledged that the human factor and the interaction between the human factor and the road environment are among the most common causes of road accidents. Intersections are among the most complex road environments: their geometric and traffic characteristics weigh the driver workload, affecting the driving behaviour and consequently the risk of accident. This study intends therefore to contribute for a better understanding of the relationship between different types of intersection and the human factor. The ultimate aim is to understand how at grade intersections affect the driving behaviour by comparing the drivers’ stress level for roundabouts and standard intersections. Electrodermal activity can provide a real-time assessment of the driver's stress level. Electrodermal activity was therefore collected continuously during a driving study which took place on a test environment based at Cranfield University and surrounding roads. Twenty participants were involved within the study. The analysis focused on four crossing manoeuvres on three at grade intersections (two T-junctions and a roundabout) situated on the study location. Results showed that the number of SCR peaks as well as the amplitude of the peaks are overall higher for the two manoeuvres on the roundabout. The stress level induced by each type of intersection was evaluated through an Electrodermal Impact Index which takes into account both the number and the amplitude of SCR peaks. Results suggested that the stress level induced by roundabouts is more than double that induced by standard intersections

Advances in chromosomal studies in Neottieae (Orchidaceae): constitutive heterochromatin, chromosomal rearrangements and speciation.

Abstract — In this work, we describe a karyomorphological study on three taxa of the tribe Neottieae (Orchidaceae). Epipactis aspromontana and E. schubertiorum are characterized by a chromosome complement of 2n = 2× = 38. Significant differences in heterochromatin distribution were found between them. Similarities in the karyotype structure and C-banding of E. schubertiorum and E. helleborine group have been observed. A specimen of E. aspromontana showed a triploid chromosome number. The meiosis are characterized by univalent, bivalent and trivalent forms and in some somatic metaphase cells has been possible to observe a series of aneuploid numbers with 46, 47, 48, 49, 50, 51, 52 and 53 chromosomes. The largest differences can be emphasized between the Epipactis species and Neottia nidusavis, mainly in the the karyomorphology and heterochromatin distributions. In Neottia nidusavis the evolution process seems to be determined by reversing Robertsonian mutations