160 research outputs found
A multi-case integration across the coffee, forestry and textile sectors
Amid concerns for a regulatory void in transnational fields, the principle of private regulation has become institutionalized. Many sectors have seen the emergence of multiple and overlapping standards. When comparing the sectors, there is considerable variation in standard multiplicity. We build on three institutional perspectives that have been put forward to explain the emergence of sustainability standardsâthe economic, idealist and political-institutional perspectivesâto analyze the phenomenon of standard multiplicity. Each perspective reflects a different kind of action logic and is simultaneously present and accessible to various parties involved. Based on a cross-sector analysis of standards multiplicity in the forestry, coffee and textile sectors, this article seeks to make two contributions. First, whereas these three perspectives have been presented as competing, we propose that they are complementary in offering partial explanations for different episodes in the dynamics underlying standards multiplicity in different sectors. Second, whereas most studies have analyzed standard setting in single sectors and thus have understood it as being an intra-sector phenomenon, our cross-sector analysis of the dynamics of standard setting suggests that it is propelled by both sector-specific contingencies and experiences as well as by the experiences from other sectors
M87* in space, time, and frequency
Observing the dynamics of compact astrophysical objects provides insights
into their inner workings, thereby probing physics under extreme conditions.
The immediate vicinity of an active supermassive black hole with its event
horizon, photon ring, accretion disk, and relativistic jets is a perfect pace
to study general relativity, magneto-hydrodynamics, and high energy plasma
physics. The recent observations of the black hole shadow of M87* with Very
Long Baseline Interferometry (VLBI) by the Event Horizon Telescope (EHT) open
the possibility to investigate its dynamical processes on time scales of days.
In this regime, radio astronomical imaging algorithms are brought to their
limits. Compared to regular radio interferometers, VLBI networks typically have
fewer antennas and low signal to noise ratios (SNRs). If the source is variable
during the observational period, one cannot co-add data on the sky brightness
distribution from different time frames to increase the SNR. Here, we present
an imaging algorithm that copes with the data scarcity and the source's
temporal evolution, while simultaneously providing uncertainty quantification
on all results. Our algorithm views the imaging task as a Bayesian inference
problem of a time-varying brightness, exploits the correlation structure
between time frames, and reconstructs an entire, dimensional
time-variable and spectrally resolved image at once. The degree of correlation
in the spatial and the temporal domains is inferred from the data and no form
of correlation is excluded a priori. We apply this method to the EHT
observation of M87* and validate our approach on synthetic data. The time- and
frequency-resolved reconstruction of M87* confirms variable structures on the
emission ring on a time scale of days. The reconstruction indicates extended
and time-variable emission structures outside the ring itself.Comment: 43 pages, 15 figures, 6 table
Availability of infective larvae of parasitic nematodes of sheep grazing on Kikuyu (Pennisetum clandestinum) pastures in the winter rainfall area
Thirteen groups of 4 South African mutton Merinos grazed for 4 weeks with the flock on Kikuyu pastures and were slaughtered for total and differential worm counts at necropsy. Subsequently 12 groups of 8 week tracers grazed on the pastures and were killed for worm counts post mortem. The following were present in most sheep: Teladorsagia (syn. Ostertagia) circumcincta, Trichostrongylus axei, Trichostrongylus colubriformis, Dictyocaulus filaria and Oesophagostomum venulosum. Haemonchus contortus, Nematodirus spathiger and Trichuris skrjabini were less frequently recovered. Optimal conditions for infestation of grazing sheep occurred from June (late autumn)-October (spring) when mean temperatures in any 4 week period were 40 mm of rain fell on 8 or more separate days. When the mean temperatures exceeded 20 °C pastures were safe, sheep acquiring< 1 000 worms in 4 weeks.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi.
Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.lmchunu2014mn201
Parasites in sheep grazing on Kikuyu (Pennisetum clandestinum) pastures in the winter rainfall region
Regular worm counts were done post-mortem on sheep that had grazed on Kikuyu pastures at the Elsenburg Research Station near Stellenbosch, a winter rainfall region. Major species were Trichostrongylus colubriformis, Trichostrongylus axei, while Ostertagia circumcincta was usually present in large numbers. Minor species were Haemonchus contortus, Nematodirus spathiger, Dictyocaulus filaria , Oesophagostomum venulosum, Trichuris spp., Chabertia ovina and larvae of the arthropod Oestrus ovis. Muellerius capillaris caused the formation of nodules in the lungs but were not counted. The trial started in April1982 and was concluded in March 1984. One hundred and four sheep died or were slaughtered and 99 were examined post-mortem during this period. Total worm burdens rose to a peak of 88 763 (range 67 281-124 735) worms in March 1983, i.e. sheep mortality was such that the flock had to be treated with an anthelmintic in April 1983 to prevent further losses. Kikuyu pastures provide shade, form an excellent mat, the humus layer under the grass retains moisture and is an excellent incubator for preinfective larvae and a protector for infective larvae. If these qualities are combined with more than 100 mm of rain in spring and summer, Kikuyu pastures are a paradise for the free-living stages.The articles have been scanned in colour with a HP Scanjet 5590; 600dpi.
Adobe Acrobat XI Pro was used to OCR the text and also for the merging and conversion to the final presentation PDF-format.lmchunu2014mn201
How and when do mobile media demands impact well-being? Explicating the Integrative Model of Mobile Media Use and Need Experiences (IMÂłUNE)
AstroGrid-D: Grid Technology for Astronomical Science
We present status and results of AstroGrid-D, a joint effort of
astrophysicists and computer scientists to employ grid technology for
scientific applications. AstroGrid-D provides access to a network of
distributed machines with a set of commands as well as software interfaces. It
allows simple use of computer and storage facilities and to schedule or monitor
compute tasks and data management. It is based on the Globus Toolkit middleware
(GT4). Chapter 1 describes the context which led to the demand for advanced
software solutions in Astrophysics, and we state the goals of the project. We
then present characteristic astrophysical applications that have been
implemented on AstroGrid-D in chapter 2. We describe simulations of different
complexity, compute-intensive calculations running on multiple sites, and
advanced applications for specific scientific purposes, such as a connection to
robotic telescopes. We can show from these examples how grid execution improves
e.g. the scientific workflow. Chapter 3 explains the software tools and
services that we adapted or newly developed. Section 3.1 is focused on the
administrative aspects of the infrastructure, to manage users and monitor
activity. Section 3.2 characterises the central components of our architecture:
The AstroGrid-D information service to collect and store metadata, a file
management system, the data management system, and a job manager for automatic
submission of compute tasks. We summarise the successfully established
infrastructure in chapter 4, concluding with our future plans to establish
AstroGrid-D as a platform of modern e-Astronomy.Comment: 14 pages, 12 figures Subjects: data analysis, image processing,
robotic telescopes, simulations, grid. Accepted for publication in New
Astronom
Therapeutic Reference Range for Aripiprazole in Schizophrenia Revised: a Systematic Review and Metaanalysis
Rationale: While one of the basic axioms of pharmacology postulates that there is a relationship between the concentration and effects of a drug, the value of measuring blood levels is questioned by many clinicians. This is due to the often-missing validation of therapeutic reference ranges.
Objectives: Here, we present a prototypical meta-analysis of the relationships between blood levels of aripiprazole, its target engagement in the human brain, and clinical effects and side effects in patients with schizophrenia and related disorders.
Methods: The relevant literature was systematically searched and reviewed for aripiprazole oral and injectable formulations. Population-based concentration ranges were computed (N = 3,373) and pharmacokinetic influences investigated.
Results: Fifty-three study cohorts met the eligibility criteria. Twenty-nine studies report blood level after oral, 15 after injectable formulations, and nine were positron emission tomography studies. Conflicting evidence for a relationship between concentration, efficacy, and side effects exists (assigned level of evidence low, C; and absent, D). Population-based reference ranges are well in-line with findings from neuroimaging data and individual efficacy studies. We suggest a therapeutic reference range of 120-270 ng/ml and 180-380 ng/ml, respectively, for aripiprazole and its active moiety for the treatment of schizophrenia and related disorders.
Conclusions: High interindividual variability and the influence of CYP2D6 genotypes gives a special indication for Therapeutic Drug Monitoring of oral and long-acting aripiprazole. A starting dose of 10 mg will in most patients result in effective concentrations in blood and brain. 5 mg will be sufficient for known poor metabolizers
Genome sequence of the bioplastic-producing ââKnallgasââ bacterium Ralstonia eutropha H16
The H2-oxidizing lithoautotrophic bacterium Ralstonia eutropha H16 is a metabolically versatile organism capable of subsisting, in the absence of organic growth substrates, on H2 and CO2 as its sole sources of energy and carbon. R. eutropha H16 first attracted biotechnological interest nearly 50 years ago with the realization that the organismâs ability to produce and store large amounts of poly[R-(â)-3-hydroxybutyrate] and other polyesters could be harnessed to make biodegradable plastics. Here we report the complete genome sequence of the two chromosomes of R. eutropha H16. Together, chromosome 1 (4,052,032 base pairs (bp)) and chromosome 2 (2,912,490 bp) encode 6,116 putative genes. Analysis of the genome sequence offers the genetic basis for exploiting the biotechnological potential of this organism and provides insights into its remarkable metabolic versatility
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