8,554 research outputs found
National and Regional Estimates of the Prevalence of Opiate and/or Crack Cocaine use 2008-09: A summary of key findings
<p>This report summarises the results of a follow-up study
to a three year project to estimate the prevalence of
âproblem drug useâ (defined as use of opiates and/or
crack cocaine) nationally (England only), regionally and
locally. The follow-up was carried out two years after the
final sweep of the original project, so could therefore
be considered as âsweep 5â. An overview of the national
and regional estimates are presented in this report, as are
comparisons with the estimates produced by the third
(2006-07) sweep of the study. Estimates for 2007-08 are
not available as a study was not commissioned for that
year.</p>
<p>Information about the number of people who use illicit
drugs such as heroin, other opiates or crack cocaine
is key to formulating effective policies for tackling
drug-related harm as these drugs are associated with
the highest levels of harm. It also helps inform service
provision at the local level and provides a context
in which to understand the population impact of
interventions to reduce drug-related harm.</p>
<p>Direct enumeration of those engaged in a largely covert
activity such as the use of class A drugs is difficult
and standard household survey techniques tend to
underestimate the extent of such activity. Indirect
techniques making use of various data sources offer a
more reliable way of calculating prevalence estimates for
the use of opiates and/or crack cocaine. The estimates
presented in this report are derived using two indirect
measurement techniques: the capture-recapture
method (CRC ); and the multiple indicator (MIM ) method.
These methods are described in detail in Hay et al., 2006
and Hay et al., 2007a. Methodological developments
throughout the course of the previous three sweeps are
discussed elsewhere (Hay et al., 2007b, Hay et al., 2008).
The individuals covered by this study were people aged
15 to 64 and resident in each DAT area, and known to
be using heroin, methadone, other opiate drugs or
crack cocaine.</p>
A Tone-Aided/Dual Vestigial Sideband (TA/DVSB) system for mobile satellite channels
Tone-aided modulation is one way of combatting the effects of multipath fading and Doppler frequency shifts. A new tone-aided modulation format for M-ary phase-shift keyed signals (MPSK) is discussed. A spectral null for the placement of the tone is created in the center of the MPSK signal by translating the upper sideband upwards in frequency by the same amount. The key element of the system is the algorithm for recombining the data sidebands in the receiver, a function that is performed by a specialized phase-locked loop (PLL). The system structure is discussed and simulation results showing the PLL acquisition performance are presented
Low loss Ge-on-Si waveguides operating in the 8â14 ”m atmospheric transmission window
Germanium-on-silicon waveguides were modeled, fabricated and characterized at wavelengths ranging from 7.5 to 11 ”m. Measured waveguide losses are below 5 dB/cm for both TE and TM polarization and reach values of ⌠1 dB/cm for ℠10 ”m wavelengths for the TE polarization. This work demonstrates experimentally for the first time that Ge-on-Si is a viable waveguide platform for sensing in the molecular fingerprint spectral region. Detailed modeling and analysis is presented to identify the various loss contributions, showing that with practical techniques losses below 1 dB/cm could be achieved across the full measurement range
Green human resource management: a comparative qualitative case study of a United States multinational corporation
This article explores the ways in which a multinational company (MNC) approaches Green Human Resource Management (HRM) in its British, German and Swedish subsidiaries. The authors analyze the similarities and differences in Green HRM approaches in these three European subsidiaries of a US restaurant chain. This enables the comparison of Green HRM practises and behaviors, and considers the factors that influence the subsidiaries in this particular domain. Therefore, this research addresses the current lack of international comparative research in the field of Green HRM. The methodological approach is multi-case study with 50 participants, using semi-structured interviews and focus groups. The results show evidence of pro-active environmental management, reflected through a range of operational and people-centred initiatives across the three European countries. Although there is an overarching commitment to environmental sustainability, the positioning and alignment of the environment and HR function differ amongst the subsidiaries, as does the way in which the subsidiaries choose to engage the workforce in environmental sustainability. The study identified a number of factors which explain the differences in approach including, amongst others, strategic and performance drivers and cultural dimensions, such as relationships with key stakeholders
Gestational and lactational exposure of rats to xenoestrogens results in reduced testicular size and sperm production
EHP is a publication of the U.S. government. Publication of EHP lies in the public domain and is therefore without copyright.
Research articles from EHP may be used freely; however, articles from the News section of EHP may contain photographs or figures copyrighted by other commercial organizations and individuals that may not be used without obtaining prior approval from both the EHP editors and the holder of the copyright.
Use of any materials published in EHP should be acknowledged (for example, "Reproduced with permission from Environmental Health Perspectives") and a reference provided for the article from which the material was reproduced.This study assessed whether exposure of male rats to two estrogenic, environmental chemicals, 4-octylphenol (OP) and butyl benzyl phthalate (BBP) during gestation or during the first 21 days of postnatal life, affected testicular size or spermatogenesis in adulthood (90-95 days of age). Chemicals were administered via the drinking water or concentrations of 10-1000 micrograms/l (OP) or 1000 micrograms/l (BBP), diethylstilbestrol (DES; 100 micrograms/l) and an octylphenol polyethoxylate (OPP; 1000 micrograms/l), which is a weak estrogen or nonestrogenic in vitro, were administered as presumptive positive and negative controls, respectively. Controls received the vehicle (ethanol) in tap water. In study 1, rats were treated from days 1-22 after births in studies 2 and 3, the mothers were treated for approximately 8-9 weeks, spanning a 2-week period before mating throughout gestation and 22 days after giving birth. With the exception of DES, treatment generally had no major adverse effect or body weight: in most instances, treated animals were heavier than controls at day 22 and at days 90-95. Exposure to OP, OPP, or BBP at a concentration of 1000 micrograms/1 resulted in a small (5-13%) but significant (p < 0.01 or p < 0.0001) reduction in mean testicular size in studies 2 and 3, an effect that was still evident when testicular weight was expressed relative to body, weight or kidney weight. The effect of OPP is attributed to its metabolism in vivo to OP. DES exposure caused similar reductions in testicular size but also caused reductions in body weight, kidney weight, and litter size. Ventral prostate weight was reduced significantly in DES-treated rats and to minor extent in OP-treated rats. Comparable but more minor effects of treatment with DES or OP on testicular size were observed in study 1. None of the treatments had any adverse effect on testicular morphology or on the cross-sectional area of the lumen or seminiferous epithelium at stages VII-VIII of the spermatogenic cycle, but DES, OP, and BBP caused reductions of 10-21% (p < 0.05 to p < 0.001) in daily sperm production. Humans are exposed to phthalates, such as BBP, and to alkylphenol polyethoxylates, such as OP, but to what extent is unknown. More detailed studies are warranted to assess the possible risk to the development of the human testis from exposure to these and other environmental estrogens
FLOWERING LOCUS C -dependent and -independent regulation of the circadian clock by the autonomous and vernalization pathways
Background
The circadian system drives pervasive biological rhythms in plants. Circadian clocks integrate endogenous timing information with environmental signals, in order to match rhythmic outputs to the local day/night cycle. Multiple signaling pathways affect the circadian system, in ways that are likely to be adaptively significant. Our previous studies of natural genetic variation in Arabidopsis thaliana accessions implicated FLOWERING LOCUS C (FLC) as a circadian-clock regulator. The MADS-box transcription factor FLC is best known as a regulator of flowering time. Its activity is regulated by many regulatory genes in the "autonomous" and vernalization-dependent flowering pathways. We tested whether these same pathways affect the circadian system.
Results
Genes in the autonomous flowering pathway, including FLC, were found to regulate circadian period in Arabidopsis. The mechanisms involved are similar, but not identical, to the control of flowering time. By mutant analyses, we demonstrate a graded effect of FLC expression upon circadian period. Related MADS-box genes had less effect on clock function. We also reveal an unexpected vernalization-dependent alteration of periodicity.
Conclusion
This study has aided in the understanding of FLC's role in the clock, as it reveals that the network affecting circadian timing is partially overlapping with the floral-regulatory network. We also show a link between vernalization and circadian period. This finding may be of ecological relevance for developmental programing in other plant species
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