University of Luxembourg

About: University of Luxembourg is a education organization based out in Luxembourg, Luxembourg. It is known for research contribution in the topics: Context (language use) & Computer science. The organization has 4744 authors who have published 22175 publications receiving 381824 citations.

Collaborative analysis of alpha-synuclein gene promoter variability and Parkinson disease.

Abstract: ContextIdentification and replication of susceptibility genes for Parkinson disease at the population level have been hampered by small studies with potential biases. α-Synuclein (SNCA) has been one of the most promising susceptibility genes, but large-scale studies have been lacking.ObjectiveTo determine whether allele-length variability in the dinucleotide repeat sequence (REP1) of the SNCA gene promoter is associated with Parkinson disease susceptibility, whether SNCA promoter haplotypes are associated with Parkinson disease, and whether REP1 variability modifies age at onset.Design, Setting, and ParticipantsWe performed a collaborative analysis of individual-level data on SNCA REP1 and flanking markers in patients with Parkinson disease and controls. Study site recruitment, data collection, and analyses were performed between April 5, 2004, and December 31, 2005. Eighteen participating sites of a global genetics consortium provided clinical data. Genotyping was performed for SNCA REP1, −770, and −116 markers at individual sites; however, each site also provided 20 DNA samples for regenotyping centrally.Main Outcome MeasuresMeasures included estimations of Hardy-Weinberg equilibrium in controls; a test of heterogeneity; analyses for association of single variants or haplotypes; and survival analyses for age at onset.ResultsOf the 18 sites, 11 met stringent criteria for concordance with Hardy-Weinberg equilibrium and low genotyping error rate. These 11 sites provided complete data for 2692 cases and 2652 controls. There was no heterogeneity across studies (P>.60). The SNCA REP1 alleles differed in frequency for cases and controls (P<.001). Genotypes defined by the 263 base-pair allele were associated with Parkinson disease (odds ratio, 1.43; 95% confidence interval, 1.22-1.69; P<.001 for trend). Multilocus haplotypes differed in frequency for cases and controls (global score statistic, P<.001). Two-loci haplotypes were associated with Parkinson disease only when they included REP1 as one of the loci. However, genotypes defined by REP1 alleles did not modify age at onset (P = .55).ConclusionThis large-scale collaborative analysis demonstrates that SNCA REP1 allele-length variability is associated with an increased risk of Parkinson disease.

Systematic genome assessment of B-vitamin biosynthesis suggests co-operation among gut microbes.

Abstract: The human gut microbiota supplies its host with essential nutrients, including B-vitamins. Using the PubSEED platform, we systematically assessed the genomes of 256 common human gut bacteria for the presence of biosynthesis pathways for eight B-vitamins: biotin, cobalamin, folate, niacin, pantothenate, pyridoxine, riboflavin, and thiamin. On the basis of the presence and absence of genome annotations, we predicted that each of the eight vitamins was produced by 40-65% of the 256 human gut microbes. The distribution of synthesis pathways was diverse; some genomes had all eight biosynthesis pathways, whereas others contained no de novo synthesis pathways. We compared our predictions to experimental data from 16 organisms and found 88% of our predictions to be in agreement with published data. In addition, we identified several pairs of organisms whose vitamin synthesis pathway pattern complemented those of other organisms. This analysis suggests that human gut bacteria actively exchange B-vitamins among each other, thereby enabling the survival of organisms that do not synthesize any of these essential cofactors. This result indicates the co-evolution of the gut microbes in the human gut environment. Our work presents the first comprehensive assessment of the B-vitamin synthesis capabilities of the human gut microbiota. We propose that in addition to diet, the gut microbiota is an important source of B-vitamins, and that changes in the gut microbiota composition can severely affect our dietary B-vitamin requirements.

Problematic Use of the Mobile Phone: A Literature Review and a Pathways Model

Abstract: Despite its unambiguous advantages, cellular phone use has been associated with harmful or potentially disturbing behaviors. Problematic use of the mobile phone is considered as an inability to regulate one's use of the mobile phone, which eventually involves negative consequences in daily life (e.g., financial problems). The current article describes what can be considered dysfunctional use of the mobile phone and emphasizes its multifactorial nature. Validated assessment instruments to measure problematic use of the mobile phone are described. The available literature on risk factors for dysfunctional mobile phone use is then reviewed, and a pathways model that integrates the existing literature is proposed. Finally, the assumption is made that dysfunctional use of the mobile phone is part of a spectrum of cyber addictions that encompasses a variety of dysfunctional behaviors and implies involvement in specific online activities (e.g., video games, gambling, social networks, sex-related websites).

DFTB+, a software package for efficient approximate density functional theory based atomistic simulations

Abstract: DFTB+ is a versatile community developed open source software package offering fast and efficient methods for carrying out atomistic quantum mechanical simulations. By implementing various methods approximating density functional theory (DFT), such as the density functional based tight binding (DFTB) and the extended tight binding method, it enables simulations of large systems and long timescales with reasonable accuracy while being considerably faster for typical simulations than the respective ab initio methods. Based on the DFTB framework, it additionally offers approximated versions of various DFT extensions including hybrid functionals, time dependent formalism for treating excited systems, electron transport using non-equilibrium Green’s functions, and many more. DFTB+ can be used as a user-friendly standalone application in addition to being embedded into other software packages as a library or acting as a calculation-server accessed by socket communication. We give an overview of the recently developed capabilities of the DFTB+ code, demonstrating with a few use case examples, discuss the strengths and weaknesses of the various features, and also discuss on-going developments and possible future perspectives.

Pragmatism and educational research

Abstract: Chapter 1 Series Preface Nicholas C. Burbules Chapter 3 1. What is Pragmatism? Chapter 4 2. From Experience to Knowledge Chapter 5 3. The Process of Inquiry Chapter 6 4. Consequences of Pragmatism Chapter 7 5. Pragmatism and Educational Research