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We describe an ultra-wide-bandwidth, low-frequency receiver recently installed on the Parkes radio telescope. The receiver system provides continuous frequency coverage from 704 to 4032 MHz. For much of the band (
), the system temperature is approximately 22 K and the receiver system remains in a linear regime even in the presence of strong mobile phone transmissions. We discuss the scientific and technical aspects of the new receiver, including its astronomical objectives, as well as the feed, receiver, digitiser, and signal processor design. We describe the pipeline routines that form the archive-ready data products and how those data files can be accessed from the archives. The system performance is quantified, including the system noise and linearity, beam shape, antenna efficiency, polarisation calibration, and timing stability.
Mixing determines the environment in which crystals nucleate and grow and is therefore intrinsic to industrial crystallization. Individual nucleating and growing crystals respond directly to their microenvironment and not in a simple way to the macroenvironment, often thought of as the bulk or average environment. Because the growing crystal removes solute from solution and the dissolving crystal releases it, the solute concentration and therefore the supersaturation is in general different at the crystal surface than in the bulk. Crystals grow when the microenvironment is supersaturated, stop when it is just saturated, and dissolve when it is undersaturated. In most cases, impurities are rejected by growing crystals; therefore, each growing crystal face creates a zone of locally higher impurity concentration immediately adjacent to it. The growth rate and amount of impurity taken up by the growing crystal are functions of the impurity concentration where growth is occurring – at the crystal face itself. Mixing is the family of processes that links this local microenvironment to the macroscopic scale of the crystallizer by affecting the mass transfer between crystal and the larger environment and the dynamics of crystal suspension flow in the crystallizer. Mixing, therefore, to a large extent creates the crystal microenvironments. Furthermore, it determines the homogeneity of the macroenvironment, both temporally and spatially. Inhomogeneity in the macroenvironment affects the microenvironments around crystals, causing temporal variations as the crystals circulate from one zone to another inside the crystallizer. This is particularly important because local values of key variables such as supersaturation and solids concentration are often much more important in crystallization than the bulk or global averages of these quantities, as discussed below.
Mismatch negativity (MMN) is an event-related potential (ERP) component reflecting auditory predictive coding. Repeated standard tones evoke increasing positivity (‘repetition positivity’; RP), reflecting strengthening of the standard's memory trace and the prediction it will recur. Likewise, deviant tones preceded by more standard repetitions evoke greater negativity (‘deviant negativity’; DN), reflecting stronger prediction error signaling. These memory trace effects are also evident in MMN difference wave. Here, we assess group differences and test-retest reliability of these indices in schizophrenia patients (SZ) and healthy controls (HC).
Electroencephalography was recorded twice, 2 weeks apart, from 43 SZ and 30 HC, during a roving standard paradigm. We examined ERPs to the third, eighth, and 33rd standards (RP), immediately subsequent deviants (DN), and the corresponding MMN. Memory trace effects were assessed by comparing amplitudes associated with the three standard repetition trains.
Compared with controls, SZ showed reduced MMNs and DNs, but normal RPs. Both groups showed memory trace effects for RP, MMN, and DN, with a trend for attenuated DNs in SZ. Intraclass correlations obtained via this paradigm indicated good-to-moderate reliabilities for overall MMN, DN and RP, but moderate to poor reliabilities for components associated with short, intermediate, and long standard trains, and poor reliability of their memory trace effects.
MMN deficits in SZ reflected attenuated prediction error signaling (DN), with relatively intact predictive code formation (RP) and memory trace effects. This roving standard MMN paradigm requires additional development/validation to obtain suitable levels of reliability for use in clinical trials.
There is a high and increasing proportion of
single-parent families in Jamaica. This has raised
concerns about the potential impact of single-parent
families on the social, cognitive and behavioural
development of children, including their sexual
relationships. The aim of this study was to
investigate the association between being raised in
a single-parent family and age of sexual debut among
young people in Jamaica. The study was
cross-sectional in design, and based on a
multi-stage sampling procedure. The study was
conducted in July/September 2016. The study sample
comprised 233 respondents (110 males and 123
females) aged from 18 to 35 years (mean 26.37 years;
SD 5.46). Respondents completed a self-administered
questionnaire with questions on socio-demographic
characteristics, family structure, sexual debut and
current sexual behaviour. Ninety-seven (41.7%)
respondents grew up in single-parent families. A
total of 201 (86.3%) had had sex (102 males and 99
females). Their mean age of sexual debut was 15.51
years (SD 3.41). Sixty-five (32.3%) had early sexual
debut (<16 years). Respondents from
single-parent families were more likely to have had
early sexual debut (56.9%; n=37)
compared with those from two-parent families (43.1%,
p=0.004). Only 44.6%
(n=29) of those who experienced
early sexual debut used a condom during their first
sexual encounter compared with 73%
(n=100) of those who had a later
sexual debut (≥16 years;
p=<0.001). A single-father
family structure was a significant predictor of
early sexual debut (AOR 5.5; 95%CI: 1.1–25.8). The
study found a significant association between
single-parent family structure and age of sexual
Prior optical coherence tomography (OCT) studies of schizophrenia have identified thinning of retinal layers. However, findings have varied across reports, and most studies have had serious methodological limitations. To address unresolved issues, we determined whether: (1) retinal thinning in schizophrenia occurs independently of comorbid medical conditions that affect the retina; (2) thinning is independent of antipsychotic medication dose; (3) optic nerve parameters are abnormal in schizophrenia; and (4) OCT indices are related to visual and cognitive impairments common in schizophrenia.
A total of 32 people with schizophrenia and 32 matched controls participated. Spectral domain OCT generated data on retinal nerve fiber layer (RNFL), macula, and ganglion cell-inner plexiform layer (GCL-IPL) thickness, in addition to cup volume and the cup-to-disc ratio at the optic nerve head. Subjects with schizophrenia also completed measures of symptoms, visual processing, and IQ.
The groups did not differ on RNFL, macula, or GCL-IPL thickness. However, thinning of these layers was related to the presence of diabetes or hypertension across the sample as a whole. The schizophrenia group demonstrated enlarged cup volume and an enlarged cup-to-disc ratio in both eyes, which were unrelated to medical comorbidity, but were related to increased cognitive symptoms.
Past reports of retinal thinning may be artifacts of medical comorbidity that is over-represented in schizophrenia, or other confounds. However, optic nerve head abnormalities may hold promise as biomarkers of central nervous system abnormality, including cognitive decline, in schizophrenia.
What is progress and what is not progress? We can talk about progress in lots of different arenas; we will focus primarily on economic and scientific progress, but also make brief reference to cultural and moral progress. In our discussion, we want to distinguish, especially, between overall, long-term progress and narrower, shorter-term progress or regress. We will refer to these as “global” and “local” progress, respectively. Of course, one can also regress; therefore, we will also look at instances where progress, along some dimension, slows or even moves backwards. Generally, such regress is local, and often still in a context of broader, global progress. In scientific progress, for example, there are many instances of short-term progress which, if not completely discarded or disproved, are at least substantially modified or fundamentally challenged. And yet, those research paths, even when later abandoned, still contributed to the overall progress of the field. In that sense, the regress (that is, rejection or modification of previous theories) is corrected by, but not in conflict with, the overall progress. In the case of economic progress, the concept of regress usually takes on a different form in which things that aren’t advancing progress don’t necessarily stop it, but are simply retarding progress — that is, making the rate of progress less efficient. The consequence, we suggest, is that when talking about economic progress, objections to certain consequences of economic progress (for instance, income inequality — a type of regress, in our terminology) should not be cordoned off and dealt with independently, but should be incorporated into the way we think about economic progress itself — as instances of local regress within a context of global progress. We explore the effects of these different relations between progress and regress to suggest some of the challenges those seeking to broaden the standard measure, GDP, to incorporate other social values of well-being will face moving forward.
I examine acquisitions of private firms by public acquirers to better understand the effects of financial constraints on the division of economic gains in takeovers. Empirical tests exploit interstate bank branching deregulation, which relaxes financial constraints on private firms and can strengthen their bargaining position in an acquisition. Using a proxy for the degree to which targets depend on acquirers for financing, I find that private targets depend less on acquirers as a result of interstate bank branching deregulation. Relaxing financial constraints on private targets leads to an increase in target valuation multiples and a decrease in acquirer wealth gains.
The Livingstone's fruit bat Pteropus livingstonii is endemic to the small islands of Anjouan and Mohéli in the Comoros archipelago, Indian Ocean. The species is under threat from anthropogenic pressure on the little that remains of its forest habitat, now restricted to the islands’ upper elevations and steepest slopes. We report the results of the most comprehensive survey of this species to date, and present recommendations for ongoing field conservation efforts and monitoring. Morning counts were conducted at roost sites in the wet and dry seasons during 2011–2013. Habitat structure around the roosting sites was characterized and roost numbers compared, to investigate the potential effect of habitat loss and degradation. We estimate the population to comprise c. 1,260 individuals distributed across 21 roosts on the two islands. All occupied roosting sites were restricted to a narrow altitudinal range, and roosting populations in agroforestry areas were smaller than those found in degraded and undisturbed forest. Only one of the 16 roosts on Anjouan was found in undisturbed, old-growth forest with no nearby signs of clearance for agriculture or landslides following tree-felling upslope. Following a suspected severe population decline as a result of widespread and long-term forest loss Livingstone's fruit bat has been recategorized as Critically Endangered on the IUCN Red List.
To evaluate the association of airborne colony-forming units (CFU) at incision sites during implantation of prostheses with the incidence of either incisional or prosthesis-related surgical site infections.
Randomized, controlled trial.
Primary, public institution.
Three hundred patients undergoing total hip arthroplasty, instrumented spinal procedures, or vascular bypass graft implantation.
Patients were randomly assigned in a 1:1 ratio to either the intervention group or the control group. A novel device (Air Barrier System), previously shown to reduce airborne CFU at incision sites, was utilized in the intervention group. Procedures assigned to the control group were performed without the device, under routine operating room atmospheric conditions. Patients were followed up for 12 months to determine whether airborne CFU levels at the incision sites predicted the incidence of incisional or prosthesis-related infection.
Data were available for 294 patients, 148 in the intervention group and 146 in the control group. CFU density at the incision site was significantly lower in the intervention group than in the control group (P<.001). The density of airborne CFU at the incision site during the procedures was significantly related to the incidence of implant infection (P=.021). Airborne CFU densities were 4 times greater in procedures with implant infection versus no implant infection. All 4 of the observed prosthesis infections occurred in the control group.
Reduction of airborne CFU specifically at the incision site during operations may be an effective strategy to reduce prosthesis-related infections. Trial Registration: clinicaltrials.gov Identifier: NCT01610271
Although birds are among the best studied taxa, many of the globally threatened species lack the information required to fully assess their conservation status and needs. One such species is the Anjouan Scops Owl Otus capnodes which was presumed extinct until its rediscovery to science in 1992. Based on the limited extent and decline of the moist forests in the highlands of Anjouan in the Comoro Islands, a population size of only 100–200 pairs was estimated and the species was classified as ‘Critically Endangered’. The current study is the first comprehensive survey ever conducted on this species, and aimed to establish the current distribution and population size. Point counts with distance sampling were conducted across the agroforestry and forest zones of Anjouan in both a dry and wet season. A niche suitability model predicted the species distribution to be wider than expected with owls observed as low as 300 m altitude and in highly modified agroforestry habitats. However, the encounter rate in natural relatively undisturbed forest was significantly greater than in other habitats. The wider than expected geographic range of O. capnodes supports a possible downlisting of this species on the IUCN Red List to ‘Endangered’. Population size was found to be far greater than previously thought, at approximately 3,450 individual owls in the dry season and 5,450 in the wet season. These results show the importance of investing in robust surveys of poorly known and cryptic bird species, and provide up to date and important information for landscape scale conservation planning in the Comoros Islands.
A rare find was made in 2012 when a metal-detectorist on land near Bridge, a few miles south of Canterbury, Kent, recovered a copper alloy brooch, other metal items, and a quantity of burnt bone contained in a near complete, probably imported Gallic, helmet of Iron Age type. Excavation was undertaken to ascertain the immediate context of the helmet, confirm that it represented a cremation burial, and determine if it formed part of a larger funerary deposit. The helmet and brooch suggest a burial date in the mid-1st century bc and the apparently isolated cremation burial, of a possibly female adult, can be broadly placed within the Aylesford–Swarling tradition; the helmet taking the place of a more usual pottery cinerary urn. Cropmark evidence suggests that the burial was made within a wider landscape of Iron Age occupation.
This article is an executive summary of a report from the Centers for Disease Control and Prevention Ventilator-Associated Pneumonia Surveillance Definition Working Group, entitled “Developing a new, national approach to surveillance for ventilator-associated events” and published in Critical Care Medicine. The full report provides a comprehensive description of the Working Group process and outcome.
In September 2011, the Centers for Disease Control and Prevention (CDC) convened a Ventilator-Associated Pneumonia (VAP) Surveillance Definition Working Group to organize a formal process for leaders and experts of key stakeholder organizations to discuss the challenges of VAP surveillance definitions and to propose new approaches to VAP surveillance in adult patients (Table 1).
Common mental disorders are more prevalent in areas of high neighbourhood socioeconomic deprivation but whether the prevalence varies with neighbourhood income inequality is not known.
To investigate the hypothesis that the interaction between small-area income deprivation and income inequality was associated with individual mental health.
Multilevel analysis of population data from the Welsh Health Survey, 2003/04-2010. A total of 88623 respondents aged 18-74 years were nested within 50587 households within 1887 lower super output areas (neighbourhoods) and 22 unitary authorities (regions), linked to the Gini coefficient (income inequality) and the per cent of households living in poverty (income deprivation). Mental health was measured using the Mental Health Inventory MHI-5 as a discrete variable and as a ‘case’ of common mental disorder.
High neighbourhood income inequality was associated with better mental health in low-deprivation neighbourhoods after adjusting for individual and household risk factors (parameter estimate +0.70 (s.e. =0.33), P=0.036; odds ratio (OR) for common mental disorder case 0.92, 95% CI 0.88-0.97). Income inequality at regional level was significantly associated with poorer mental health (parameter estimate −1.35 (s.e.=0.54), P=0.012; OR=1.13, 95% CI 1.04-1.22).
The associations between common mental disorders, income inequality and income deprivation are complex. Income inequality at neighbourhood level is less important than income deprivation as a risk factor for common mental disorders. The adverse effect of income inequality starts to operate at the larger regional level.