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The current study examined whether social status and social integration, two related but distinct indicators of an adolescent's standing within a peer network, mediate the association between risky symptoms (depressive symptoms and deviant behavior) and substance use across adolescence. The sample of 6,776 adolescents participated in up to seven waves of data collection spanning 6th to 12th grades. Scores indexing social status and integration were derived from a social network analysis of six schools and subsequent psychometric modeling. Results of latent growth models showed that social integration and status mediated the relation between risky symptoms and substance use and that risky symptoms mediated the relation between social standing and substance use during the high school transition. Before this transition, pathways involving deviant behavior led to high social integration and status and in turn to substance use. After this transition, both deviant behavior and depressive symptoms led to low social integration and status and in turn greater substance use. These findings suggest that the high school transition is a risky time for substance use related to the interplay of increases in depressive symptoms and deviant behavior on the one hand and decreases in social status and integration on the other.
We studied neuroinflammation in individuals with late-life, depression, as a
risk factor for dementia, using [11C]PK11195 positron emission
tomography (PET). Five older participants with major depression and 13
controls underwent PET and multimodal 3T magnetic resonance imaging (MRI),
with blood taken to measure C-reactive protein (CRP). We found significantly
higher CRP levels in those with late-life depression and raised
[11C]PK11195 binding compared with controls in brain regions
associated with depression, including subgenual anterior cingulate cortex,
and significant hippocampal subfield atrophy in cornu ammonis 1 and
subiculum. Our findings suggest neuroinflammation requires further
investigation in late-life depression, both as a possible aetiological
factor and a potential therapeutic target.
Aperture synthesis is a two-step imaging process in which the final map or image is reconstructed from intermediate measurements. As an alternative to digital computers, optical computers can be used to perform the reconstruction step. Optical reconstruction can be a fast and cheap way to handle the large amount of data now being generated by earth rotation aperture synthesis arrays.
The discovery of pulsars in 1967 marked the watershed of interest in short-time-scale phenomena in radio astronomy. Ionospheric scintillation on time scales of seconds, interplanetary scintillations at tenths of seconds and solar bursts of similar duration had already been studied. But with pulsars individual pulses contained subpulses of width about 10 ms, and later observations of microstructure were to show that structure with scales of 10—100 μs were present. In other areas searches for the 10—100 ms radio pulses expected to accompany the gravitational wave events resulting from stellar collapses were made, and more recently searches have been made for the radio pulse accompanying the explosion of small black holes (Rees 1977). Work in this area is summarized by O’Sullivan et al. (1978) and Phinney and Taylor (1979).
From early experiments in 1966 (Cole 1968) the acousto-optical radio spectrograph has been developed at CSIRO to a sensitive, multi-channel spectral-line back-end. The principles of the instrument are described in detail elsewhere (Lambert 1962; Hecht 1977; Milne and Cole 1977). By means of a Bragg interaction between a laser beam and an ultrasonic beam derived from the radio signal, light is diffracted into an order whose light intensity distribution is accurately related to the power spectrum of the radio signal. In the earlier spectrographs the spectrum was recorded photographically (Cole 1973a, b; Hecht 1973) but this was limited to strong spectral features. To study weak spectral features a stable, linear system was needed with large dynamic range. The combination of an array of photodiodes and computer would be capable of observing these weak spectral features (Cole and Abies 1974). Development since 1974 has been a progressive identification of sources of thermal and mechanical instability and of excess noise in the spectrograph system.
Interesting observations have been made possible by the success of the acousto-optical radio spectrograph, a unique form of multi-channel filter type of spectral receiver whose channel outputs ian be sampled at high rates by a computer. Three spectrographs are available at the Division of Radiophysics. Two divide a 100 MHz spectral range into 512 channels and are normally dedicated to spectral-line work (Cole and Milne 1977) and solar work (Cole et al. 1978). The Parkes observations reported here use a more compact spectrograph, which gives increased performance — up to 270 MHz can be studied, divided into 256 frequency channels. The light deflector of this spectrograph was kindly supplied by Itek Corporation.
Speckle interferometry (Labeyrie 1970, 1976) is one way of overcoming the blurring effect of the atmosphere in optical astronomy. When a short exposure is taken of an image, the seeing disc (typically several seconds of arc across) is seen to contain structure (speckles) down to the resolution limit of the telescope (0″.03 arc for the Anglo-Australian telescope). A second exposure 10 or so milliseconds later will show a different pattern of structure because the atmospheric irregularities will have changed. Multiple stars or source components within the same angular range of atmospheric irregularity (i.e. isoplanatic patch several seconds of arc across) will produce similar but displaced speckle patterns, and geometrical details of the components can be obtained from an autocorrelation analysis of the speckle pattern (Dainty 1975).
In science we have good, successful laboratories and scientists and we also have wasteful, inefficient and unproductive ones. The differences are not matters of chance.
It is not an accident that just one Cambridge College, Trinity, has achieved more Nobel Prizes than all of Japan. There was something in common amongst the Nobel prize winners Todd, Adrian, Perutz, Bragg, Crick, Ryle, Hewish and Mott that I was fortunate enough to meet and, in some cases, get to know well. Of course there was the personal and intellectual calibre of these people, their drive and determination. But also, there was the laboratory culture within which they worked, a culture still benefiting from the influence of Maxwell, Thomson and Rutherford.
Research was conducted from 2011 to 2014 to determine weed population
dynamics and frequency of glyphosate-resistant (GR) Palmer amaranth with
herbicide programs consisting of glyphosate, dicamba, and residual
herbicides in dicamba-tolerant cotton. Five treatments were maintained in
the same plots over the duration of the experiment: three sequential POST
applications of glyphosate with or without pendimethalin plus diuron PRE;
three sequential POST applications of glyphosate plus dicamba with and
without the PRE herbicides; and a POST application of glyphosate plus
dicamba plus acetochlor followed by one or two POST applications of
glyphosate plus dicamba without PRE herbicides. Additional treatments
included alternating years with three sequential POST applications of
glyphosate only and glyphosate plus dicamba POST with and without PRE
herbicides. The greatest population of Palmer amaranth was observed when
glyphosate was the only POST herbicide throughout the experiment. Although
diuron plus pendimethalin PRE in a program with only glyphosate POST
improved control during the first 2 yr, these herbicides were ineffective by
the final 2 yr on the basis of weed counts from soil cores. The lowest
population of Palmer amaranth was observed when glyphosate plus dicamba were
applied regardless of PRE herbicides or inclusion of acetochlor POST.
Frequency of GR Palmer amaranth was 8% or less when the experiment was
initiated. Frequency of GR Palmer amaranth varied by herbicide program
during 2012 but was similar among all herbicide programs in 2013 and 2014.
Similar frequency of GR Palmer amaranth across all treatments at the end of
the experiment most likely resulted from pollen movement from Palmer
amaranth treated with glyphosate only to any surviving female plants
regardless of PRE or POST treatment. These data suggest that GR Palmer
amaranth can be controlled by dicamba and that dicamba is an effective
alternative mode of action to glyphosate in fields where GR Palmer amaranth
A ‘pulsar timing array’ (PTA), in which observations of a large sample of pulsars spread across the celestial sphere are combined, allows investigation of ‘global’ phenomena such as a background of gravitational waves or instabilities in atomic timescales that produce correlated timing residuals in the pulsars of the array. The Parkes Pulsar Timing Array (PPTA) is an implementation of the PTA concept based on observations with the Parkes 64-m radio telescope. A sample of 20 ms pulsars is being observed at three radio-frequency bands, 50 cm (~700 MHz), 20 cm (~1400 MHz), and 10 cm (~3100 MHz), with observations at intervals of two to three weeks. Regular observations commenced in early 2005. This paper describes the systems used for the PPTA observations and data processing, including calibration and timing analysis. The strategy behind the choice of pulsars, observing parameters, and analysis methods is discussed. Results are presented for PPTA data in the three bands taken between 2005 March and 2011 March. For 10 of the 20 pulsars, rms timing residuals are less than 1 μs for the best band after fitting for pulse frequency and its first time derivative. Significant ‘red’ timing noise is detected in about half of the sample. We discuss the implications of these results on future projects including the International Pulsar Timing Array and a PTA based on the Square Kilometre Array. We also present an ‘extended PPTA’ data set that combines PPTA data with earlier Parkes timing data for these pulsars.
To determine whether multidrug-resistant (MDR) gram-negative organisms are present in Afghanistan or Iraq soil samples, contaminate standard deployed hospital or modular operating rooms (ORs), or aerosolize during surgical procedures.
US military hospitals in the United States, Afghanistan, and Iraq.
Soil samples were collected from sites throughout Afghanistan and Iraq and analyzed for presence of MDR bacteria. Environmental sampling of selected newly established modular and deployed OR high-touch surfaces and equipment was performed to determine the presence of bacterial contamination. Gram-negative bacteria aerosolization during OR surgical procedures was determined by microbiological analysis of settle plate growth.
Subsurface soil sample isolates recovered in Afghanistan and Iraq included various pansusceptible members of Enterobacteriaceae, Vibrio species, Pseudomonas species, Acinetobacter Iwojfii, and coagulase-negative Staphylococcus (CNS). OR contamination studies in Afghanistan revealed 1 surface with a Micrococcus luteus. Newly established US-based modular ORs and the colocated fixed-facility ORs revealed no gram-negative bacterial contamination prior to the opening of the modular OR and 5 weeks later. Bacterial aerosolization during surgery in a deployed fixed hospital revealed a mean gram-negative bacteria colony count of 12.8 colony-forming units (CFU)/dm2/h (standard deviation [SD], 17.0) during surgeries and 6.5 CFU/dm2/h (SD, 7.5; P = .14) when the OR was not in use.
This study demonstrates no significant gram-negative bacilli colonization of modular and fixed-facility ORs or dirt and no significant aerosolization of these bacilli during surgical procedures. These results lend additional support to the role of nosocomial transmission of MDR pathogens or the colonization of the patient themselves prior to injury.
Interferon-alpha (IFN-α) treatment for infectious disease and cancer causes high rates of depression and fatigue, and has been used to investigate the impact of inflammatory cytokines on brain and behavior. However, little is known about the transcriptional impact of chronic IFN-α on immune cells in vivo and its relationship to IFN-α-induced behavioral changes.
Genome-wide transcriptional profiling was performed on peripheral blood mononuclear cells (PBMCs) from 21 patients with chronic hepatitis C virus (HCV) either awaiting IFN-α therapy (n=10) or at 12 weeks of IFN-α treatment (n=11).
Significance analysis of microarray data identified 252 up-regulated and 116 down-regulated gene transcripts. Of the up-regulated genes, 2′-5′-oligoadenylate synthetase 2 (OAS2), a gene linked to chronic fatigue syndrome (CFS), was the only gene that was differentially expressed in patients with IFN-α-induced depression/fatigue, and correlated with depression and fatigue scores at 12 weeks (r=0.80, p=0.003 and r=0.70, p=0.017 respectively). Promoter-based bioinformatic analyses linked IFN-α-related transcriptional alterations to transcription factors involved in myeloid differentiation, IFN-α signaling, activator protein-1 (AP1) and cAMP responsive element binding protein/activation transcription factor (CREB/ATF) pathways, which were derived primarily from monocytes and plasmacytoid dendritic cells. IFN-α-treated patients with high depression/fatigue scores demonstrated up-regulation of genes bearing promoter motifs for transcription factors involved in myeloid differentiation, IFN-α and AP1 signaling, and reduced prevalence of motifs for CREB/ATF, which has been implicated in major depression.
Depression and fatigue during chronic IFN-α administration were associated with alterations in the expression (OAS2) and transcriptional control (CREB/ATF) of genes linked to behavioral disorders including CFS and major depression, further supporting an immune contribution to these diseases.
We report on novel liquid crystals with extremely large flexoelectric coefficients in a range of ultra-fast photonic modes, namely 1) the uniform lying helix, that leads to in-plain switching, birefringence phase devices with 100 μs switching times at low fields, i.e.2-5 V/μm, and analogue or grey scale capability, 2) the uniform standing helix, using planar surface alignment and in-plane fields, with sub ms response times and optical contrasts in excess of 5000:1 with a perfect optically isotropic or black “off state”, 3) the wide temperature range blue phase that leads to field controlled reflective color, 4) chiral nematic optical reflectors electric field tunable over a wide wavelength range and 5) high slope efficiency, wide wavelength range tunable narrow linewidth microscopic liquid crystal lasers.
We have investigated a novel approach for improving GaN crystal quality by utilizing a stack of quantum dots (QDs) in GaN grown on sapphire substrates by molecular beam epitaxy. The GaN films were grown on GaN/AlN buffer layers containing multiple QDs and characterized using x-ray diffraction, photoluminescence, atomic force microscopy, and transmission electron microscopy. The density of the dislocations in the films was determined by defect delineation wet chemical etching and atomic force microscopy. It was found that the insertion of a set of multiple GaN QD layers in the buffer layer effectively reduced the density of the dislocations in the epitaxial layers. As compared to a density of ∼1010 cm-2 in typical GaN films grown on AlN buffer layers, a density of ∼3×107 cm-2 was demonstrated in GaN films grown with the QD layers. Transmission electron microscopy observations confirmed termination of threading dislocations by the QD layers.
Background and aim We investigated the haemody-namic stability and emergence characteristics of isoflur-ane/nitrous oxide anaesthesia supplemented with remifentanil or fentanyl in patients undergoing carotid endarterectomy.
Methods Anaesthesia was induced with propofol (1–2mgkg−1) and either remifentanil (O.5μgkg−1) or fentanyl (1 μgkg−1), followed by an infusion of remifentanil (0.2 μg kg−1 min−1) or fentanyl (2 μg kg−1 h−1).
Results There were no significant differences between the groups in haemodynamic variables, postoperative pain, nausea or vomiting. After induction there was a significant decrease in mean arterial pressure for both groups (P<0.001) and a decrease in heart rate (P=0.001) in the remifentanil group. In both groups these haemodynamic changes continued during maintenance of anaesthesia (P<0.05). The time to eye opening after surgery was significantly shorter with remifentanil compared with fentanyl (6.62±3.89 vs. 18.0±15.18min, P=0.015).
Conclusion Remifentanil appears to be a comparable opioid to fentanyl when supplementing isoflurane/nitrous oxide anaesthesia for carotid endarterectomy.
In this paper, we report on the fabrication and characterization of pure and Al doped Ta2O5 thin films fabricated by metalorganic solution deposition (MOSD) technique. The pure and Aldoped Ta2O5 thin films were fabricated by spin-coating technique using room temperature processed carboxylate-alkoxide precursor solution. The structure of the films was analyzed by xray diffraction (XRD). The surface and cross-sectional morphology of the films were examined by field emission scanning electron microscope (FESEM) and atomic force microscope (AFM). The electrical measurements were conducted on films in MIM configuration using Pt as the top and bottom electrode. The effects of Al concentration and the post-deposition annealing temperature on the structural, dielectric, and insulating properties were analyzed. The effects of the applied bias and the measurement temperature on the dielectric and insulating properties were also analyzed to establish the stability and reliability of Al doped Ta2O5 thin films.