2,141 research outputs found
Elastic modulus in the crystalline region of poly(p-phenylene terephthalamide)
Fibres from aromatic polyamides have a much higher Young's modulus than fibres from aliphatic polyamides. In order to contribute to the explanation of this observed difference we looked at one of the ultimate properties, the elastic modulus in the crystalline region in the chain direction (Ecr). We carried out measurements on a bundle of filaments of PRD 49 fibre, which we identified by i.r. and X-ray analyses as poly(p-phenylene terephthalamide). With the X-ray technique we determined the lattice extensions under loading and from these data the Ecr was calculated. The Ecr was found to be 20 × 1011 dyne/cm2 which is in good agreement with the calculated Ecr, but not very different from that of nylon-6,6. The Young's modulus was found to be 11 × 1011 dyne/cm2
National scientific capabilities and technological performance: An exploration of emerging industrial relevant research domains.
Today's theories and models on innovation stress the importance of scientific capabilities and science-technology proximity, especially in new emerging fields of economic activity. In this contribution we examine the relationship between national scientific capabilities, the science intensity of technology and technological performance within six promising industrial fields. Our findings reveal that national technological performance is positively associated with scientific capabilities. Countries performing better on a technological level are characterized both by larger numbers of publications and by numbers of involved institutions that exceed average expected values. The latter observation holds for both companies and knowledge generating institutes actively involved in scientific activities. As such, our findings seem to suggest beneficial effects of scientific capabilities shouldered by a multitude of organizations. In addition, higher numbers of patent activity coincide with higher levels of science intensity pointing out the relevance of science 'proximity' when developing technology in newer, emerging fields. Limitations and directions for further research are discussed.Performance; Research; Theory; Models; Model; Innovation; Field; Science; Intensity; Technology; Country; Expected; Value; Companies; Knowledge; Effects;
Пам'яті Івана Григоровича Гуракова
20 вересня 2004 року, не доживши 4 дні до свого 70-річчя, пішов у вічність колишній головний гідрогеолог, начальник Трускавецької гідрогеологічно режимно-експлуатаційної станції Іван Григорович Гураков. Пішов тихо і раптово в далекій землі Ізраїлю
Cruise report hydro acoustic survey for blue whiting (Micromesistius poutassou) with R.V. Tridens, 17 March - 04 April 2008
This is the report of the Dutch part of the international North East Atlantic hydro acoustic survey for blue whiting. The survey is coordinated by ICES and has been executed annually. The purpose of the survey is to estimate the blue whiting stock of the North East Atlantic. The ICES uses this estimation is as a “tuning index” to assess the North East Atlantic blue whiting stock. The applied method was echo integration. By sailing transects over the survey area, the total acoustic cross-section can be calculated by surface area sampled. Trawling identified species composition of localized schools. The length composition of each species was determined. Blue whiting was examined on age and fecundity from which a split up stock structure was mad
Diagnostic approach to paediatric movement disorders:a clinical practice guide
Paediatric movement disorders (PMDs) comprise a large group of disorders (tics, myoclonus, tremor, dystonia, chorea, Parkinsonism, ataxia), often with mixed phenotypes. Determination of the underlying aetiology can be difficult given the broad differential diagnosis and the complexity of the genotype-phenotype relationships. This can make the diagnostic process time-consuming and difficult. In this overview, we present a diagnostic approach for PMDs, with emphasis on genetic causes. This approach can serve as a framework to lead the clinician through the diagnostic process in eight consecutive steps, including recognition of the different movement disorders, identification of a clinical syndrome, consideration of acquired causes, genetic testing including next-generation sequencing, post-sequencing phenotyping, and interpretation of test results. The aim of this approach is to increase the recognition and diagnostic yield in PMDs.</p
Novel parvoviruses in reptiles and genome sequence of a lizard parvovirus shed light on Dependoparvovirus genus evolution.
Here, we report the detection and partial genome characterization of two novel reptilian parvoviruses derived from a short-tailed pygmy chameleon (Rampholeon brevicaudatus) and a corn snake (Pantherophis guttatus) along with the complete genome analysis of the first lizard parvovirus, obtained from four bearded dragons (Pogona vitticeps). Both homology searches and phylogenetic tree reconstructions demonstrated that all are members of the Dependoparvovirus genus. Even though most dependoparvoviruses replicate efficiently only in co-infections with large DNA viruses, no such agents could be detected in one of the bearded dragon samples, hence the possibility of autonomous replication was explored. The alternative ORF encoding the full assembly-activating protein (AAP), typical for the genus, could be obtained from reptilian parvoviruses for the first time, with a structure that appears to be more ancient than that of avian and mammalian parvoviruses. All three viruses were found to harbor short introns as previously observed for snake adeno-associated virus (SAAV), shorter than that of any non-reptilian dependoparvovirus. According to the phylogenetic calculations based on full non-structural protein (Rep) and AAP sequences, the monophyletic cluster of reptilian parvoviruses seems to be the most basal out of all lineages of genus Dependoparvovirus. The suspected ability for autonomous replication, results of phylogenetic tree reconstruction, intron lengths and the structure of the AAP, suggested that a single Squamata origin instead of the earlier assumed diapsid (common avian-reptilian) origin is more likely for the genus Dependoparvovirus of the Parvoviridae family
Globalisation of science in kilometres
The ongoing globalisation of science has undisputedly a major impact on how
and where scientific research is being conducted nowadays. Yet, the big picture
remains blurred. It is largely unknown where this process is heading, and at
which rate. Which countries are leading or lagging? Many of its key features
are difficult if not impossible to capture in measurements and comparative
statistics. Our empirical study measures the extent and growth of scientific
globalisation in terms of physical distances between co-authoring researchers.
Our analysis, drawing on 21 million research publications across all countries
and fields of science, reveals that contemporary science has globalised at a
fairly steady rate during recent decades. The average collaboration distance
per publication has increased from 334 kilometres in 1980 to 1553 in 2009.
Despite significant differences in globalisation rates across countries and
fields of science, we observe a pervasive process in motion, moving towards a
truly interconnected global science system
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