163 research outputs found
Communities, Knowledge, and Innovation: Indian Immigrants in the US Semiconductor Industry
This paper investigates the influence of technological, geographic, and ethnic communities on the innovativeness of Indian inventors. We study Indian inventors in the semiconductor industry in the US and examine their patenting profiles between 1975 and 1999 to identify the influences on the quantity and quality of their innovations. We find that inventors who rely on knowledge from technological and geographic communities enhance their innovativeness. Knowledge from the ethnic Indian community is related to inventor innovativeness in the form of an inverted U. The negative effect of knowledge gained from the ethnic community on innovativeness is pronounced for experienced inventors.innovation, knowledge, semiconductor industry
Caractérisation des bassins et des systèmes de production fruitière dans les savanes d'Afrique centrale
International audienceL'absence de connaissance sur le fonctionnement des exploitations fruitières dans les savanes d'Afrique centrale et les principaux facteurs de blocage constituent un handicap pour élaborer une stratégie de développement de la filière. Entre 2005 et 2008, une enquête de caractérisation des bassins et des systèmes de production à activité fruitière a été conduite auprès d'un échantillon de 480 exploitations « fruitières » choisies au hasard, soit 175 au Cameroun, 91 en RCA et 163 au Tchad. Sept (7) espèces fruitières ont été répertoriées, comptant 106 085 arbres dont des manguiers (43,33 %), des bananiers (26,75 %), des agrumes (9,17 %), des avocatiers (8,52 %), des goyaviers (6,48 %), des anacardiers (3,6 %) et des papayers (2,14 %). Les variétés introduites par la recherche sont peu présentes. Quatre bassins fruitiers ont été identifiés dont deux sont transfrontaliers au Cameroun et au Tchad et les deux autres sont spécifiques à la République centrafricaine et au plateau de l'Adamaoua (Cameroun). Le premier type d'exploitation est un système dominé par les vivriers avec des surfaces inférieures à 1 ha, les cultures fruitières représentent jusqu'à 20 % de la marge brute totale (MBT), qui annuellement ne dépasse pas 200 000 F CFA par exploitation. Le second type d'exploitation avec des surfaces comprises entre 1 et 5 ha avec le coton comme culture dominante dégage une marge brute (MB) verger faible (moins de 100 000 F CFA/actif/an) et dont la MBT ne dépasse pas 300 000 F CFA. Le troisième type regroupe les exploitations de surface plus importante (5 à 10 ha) basé sur l'arboriculture (80 %) et la MBT annuelle dégagée est comprise entre 300 000 et 500 000 F CFA. Le type 4 regroupe les exploitations industrielles de plus de 20 à 40 ha mis en œuvre par des élites urbaines. Les MB verger représentent plus de 80 % de la MBT (600 000 à 2 000 000 F CFA). Les contraintes de production sont d'ordre phytosanitaires, agronomiques et socio-économiques. Les fruits sont consommés localement ou vendus sur les marchés urbains. La proportion non négligeable des systèmes de production de type 3 et 4 peut être un indice de durabilité du système de production à activité fruitière. Les implications des différents résultats sur la performance des exploitations agricoles en zone de savanes sont discutées
HLA genotyping in the international Type 1 Diabetes Genetics Consortium
Background Although human leukocyte antigen (HLA) DQ and
DR loci appear to confer the strongest genetic risk for
type 1 diabetes, more detailed information is required for other loci within the
HLA region to understand causality and stratify additional risk factors. The
Type 1 Diabetes Genetics Consortium (T1DGC) study design included
high-resolution genotyping of HLA-A, B,
C, DRB1, DQ, and
DP loci in all affected sibling pair and trio families, and
cases and controls, recruited from four networks worldwide, for analysis with
clinical phenotypes and immunological markers
Outcome of the First wwPDB Hybrid / Integrative Methods Task Force Workshop
Structures of biomolecular systems are increasingly computed by integrative modeling that relies on varied types of experimental data and theoretical information. We describe here the proceedings and conclusions from the first wwPDB Hybrid/Integrative Methods Task Force Workshop held at the European Bioinformatics Institute in Hinxton, UK, on October 6 and 7, 2014. At the workshop, experts in various experimental fields of structural biology, experts in integrative modeling and visualization, and experts in data archiving addressed a series of questions central to the future of structural biology. How should integrative models be represented? How should the data and integrative models be validated? What data should be archived? How should the data and models be archived? What information should accompany the publication of integrative models
Social Salience and the Sociolinguistic Monitor: A Case Study of ING and TH-fronting in Britain
This article examines the role of social salience, or the relative ability of a linguistic variable to evoke social meaning, in structuring listeners’ perceptions of quantitative sociolinguistic distributions. Building on the foundational work of Labov et al. (2006, 2011) on the “sociolinguistic monitor” (a proposed cognitive mechanism responsible for sociolinguistic perception), we examine whether listeners’ evaluative judgments of speech change as a function of the type of variable presented. We consider two variables in British English, ING and TH-fronting, which we argue differ in their relative social salience. Replicating the design of Labov et al.’s studies, we test 149 British listeners’ reactions to different quantitative distributions of these variables. Our experiments elicit a very different pattern of perceptual responses than those reported previously. In particular, our results suggest that a variable’s social salience determines both whether and how it is perceptually evaluated. We argue that this finding is crucial for understanding how sociolinguistic information is cognitively processed
Ixodes ricinus Tick Lipocalins: Identification, Cloning, Phylogenetic Analysis and Biochemical Characterization
BACKGROUND: During their blood meal, ticks secrete a wide variety of proteins that interfere with their host's defense mechanisms. Among these proteins, lipocalins play a major role in the modulation of the inflammatory response. METHODOLOGY/PRINCIPAL FINDINGS: Screening a cDNA library in association with RT-PCR and RACE methodologies allowed us to identify 14 new lipocalin genes in the salivary glands of the Ixodes ricinus hard tick. A computational in-depth structural analysis confirmed that LIRs belong to the lipocalin family. These proteins were called LIR for "Lipocalin from I. ricinus" and numbered from 1 to 14 (LIR1 to LIR14). According to their percentage identity/similarity, LIR proteins may be assigned to 6 distinct phylogenetic groups. The mature proteins have calculated pM and pI varying from 21.8 kDa to 37.2 kDa and from 4.45 to 9.57 respectively. In a western blot analysis, all recombinant LIRs appeared as a series of thin bands at 50-70 kDa, suggesting extensive glycosylation, which was experimentally confirmed by treatment with N-glycosidase F. In addition, the in vivo expression analysis of LIRs in I. ricinus, examined by RT-PCR, showed homogeneous expression profiles for certain phylogenetic groups and relatively heterogeneous profiles for other groups. Finally, we demonstrated that LIR6 codes for a protein that specifically binds leukotriene B4. CONCLUSIONS/SIGNIFICANCE: This work confirms that, regarding their biochemical properties, expression profile, and sequence signature, lipocalins in Ixodes hard tick genus, and more specifically in the Ixodes ricinus species, are segregated into distinct phylogenetic groups suggesting potential distinct function. This was particularly demonstrated by the ability of LIR6 to scavenge leukotriene B4. The other LIRs did not bind any of the ligands tested, such as 5-hydroxytryptamine, ADP, norepinephrine, platelet activating factor, prostaglandins D2 and E2, and finally leukotrienes B4 and C4.Journal ArticleResearch Support, Non-U.S. Gov'tSCOPUS: ar.jinfo:eu-repo/semantics/publishe
Diversity of Beetle Genes Encoding Novel Plant Cell Wall Degrading Enzymes
Plant cell walls are a heterogeneous mixture of polysaccharides and proteins that require a range of different enzymes to degrade them. Plant cell walls are also the primary source of cellulose, the most abundant and useful biopolymer on the planet. Plant cell wall degrading enzymes (PCWDEs) are therefore important in a wide range of biotechnological processes from the production of biofuels and food to waste processing. However, despite the fact that the last common ancestor of all deuterostomes was inferred to be able to digest, or even synthesize, cellulose using endogenous genes, all model insects whose complete genomes have been sequenced lack genes encoding such enzymes. To establish if the apparent “disappearance” of PCWDEs from insects is simply a sampling problem, we used 454 mediated pyrosequencing to scan the gut transcriptomes of beetles that feed on a variety of plant derived diets. By sequencing the transcriptome of five beetles, and surveying publicly available ESTs, we describe 167 new beetle PCWDEs belonging to eight different enzyme families. This survey proves that these enzymes are not only present in non-model insects but that the multigene families that encode them are apparently undergoing complex birth-death dynamics. This reinforces the observation that insects themselves, and not just their microbial symbionts, are a rich source of PCWDEs. Further it emphasises that the apparent absence of genes encoding PCWDEs from model organisms is indeed simply a sampling artefact. Given the huge diversity of beetles alive today, and the diversity of their lifestyles and diets, we predict that beetle guts will emerge as an important new source of enzymes for use in biotechnology
The Presence of the Iron-Sulfur Motif Is Important for the Conformational Stability of the Antiviral Protein, Viperin
Viperin, an antiviral protein, has been shown to contain a CX3CX2C motif, which is conserved in the radical S-adenosyl-methionine (SAM) enzyme family. A triple mutant which replaces these three cysteines with alanines has been shown to have severe deficiency in antiviral activity. Since the crystal structure of Viperin is not available, we have used a combination of computational methods including multi-template homology modeling and molecular dynamics simulation to develop a low-resolution predicted structure. The results show that Viperin is an α -β protein containing iron-sulfur cluster at the center pocket. The calculations suggest that the removal of iron-sulfur cluster would lead to collapse of the protein tertiary structure. To verify these predictions, we have prepared, expressed and purified four mutant proteins. In three mutants individual cysteine residues were replaced by alanine residues while in the fourth all the cysteines were replaced by alanines. Conformational analyses using circular dichroism and steady state fluorescence spectroscopy indicate that the mutant proteins are partially unfolded, conformationally unstable and aggregation prone. The lack of conformational stability of the mutant proteins may have direct relevance to the absence of their antiviral activity
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