Search

The multi-decade neutron dosimeter and imaging diagnostic (MDND) is a passive diagnostic that utilizes the polyethylene (n, p) nuclear reaction to enhance the diagnostic's sensitivity for time and energy integrated neutron measurements in the range of 2.45–14.1 MeV. The MDND utilizes a combination of radiochromic film, phosphor image plates, and solid-state nuclear track detectors, with the goal of providing several orders of magnitude of dynamic range in terms of measured neutron fluence. The diagnostic design was guided by simulations in the Monte Carlo N-Particle (MCNP) transport code to determine the optimum thickness of the polyethylene convertor for maximum proton fluence incident on the detection medium as a function of incident neutron energy. In addition, the simulation results of complete diagnostic assemblies, or "stacks," were used to determine the total dynamic range of an MDND in terms of measured neutron source yield, which was found to be between around 107 and 1015 emitted into 4π with the detector located 1 m away from the source. Complimentary to these simulations, individual detectors within a stack were simulated and analyzed to determine response as a function of neutron energy and yield. This work presents the diagnostic design, MCNP simulation results, and analysis of expected signals for varying neutron sources. [ABSTRACT FROM AUTHOR]

The double-shell inertial confinement fusion campaign, which consists of an aluminum ablator, a foam cushion, a high-Z pusher (tungsten or molybdenum), and liquid deuterium–tritium (DT) fuel, aims for its first DT filled implosions on the National Ignition Facility (NIF) in 2024. The high-Z, high density pusher does not allow x-rays to escape the double-shell capsule. Therefore, nuclear diagnostics such as the Gamma Reaction History (GRH) diagnostic on the NIF are crucial for understanding high-Z implosion performance. To optimize the GRH measurement of fusion reaction history and the pusher's areal density, the MCNP6.3-based forward model of the detector was built. When calculating the neutron-induced inelastic gamma ray production, the interaction of neutrons with the compressed fuel was additionally included. By folding the calculated gamma ray spectrum output and the previously calibrated GRH detector responses, the optimum set of GRH energy thresholds for measuring the pusher areal density is determined to be 2.9 and 6.3 MeV for DT double-shell experiments. In addition, the effect of the down-scattering of neutrons on the gamma ray spectrum, the minimum required yield for measurements, and the attenuation of the gamma rays through the pusher are analyzed. [ABSTRACT FROM AUTHOR]

A 16-channel fiber optically coupled radiation detection array has been developed for studies of radiation asymmetries and emission histories from the Verus Research 750-kJ Dense Plasma Focus. Each detector in the array consists of a light-tight housing with a plastic scintillator coupled to a fiber optic that is fed into one channel of a multi-anode photomultiplier tube (PMT). The PMT and associated electronics are located in a remote electrically shielded control room. The detector head is configurable for using a Be-9 foil to take advantage of the 9Be(n,α)6He reaction as a fast neutron activation detector or with a bare scintillator alone to record the radiation emission history. Fiber optically coupling the detector head not only provides electrical isolation in the pulsed power environment but also allows the spatial footprint of the detector array to be reduced with concomitant flexibility in positioning each individual detector head. The array allows for spatially resolved neutron yield and radiation waveform measurements for fast z-pinches. The activation detector heads were calibrated for the total neutron yield against silver and indium activation counters for the total neutron yield. Fiber scintillation was found to contribute to the time-resolved detector head signals and was accounted for. [ABSTRACT FROM AUTHOR]

Magmatic-textured zircon from medium- to high-K calc-alkaline Warraweena Volcanics (WV) in two drill holes have yielded concordant U-Pb dates of 417 ± 3.5 and 414 ± 4.0 Ma and are interpreted as maximum emplacement ages. The Warraweena volcanics were previously considered to be either Neoproterozoic or Macquarie arc equivalents. Whole-rock εNdt values of these volcanics are +4.5 and +4.8. Along strike of the drill holes, Devonian zircon U-Pb ages (411 ± 5.5 Ma) were obtained from coherent S-type rhyolite flows that have highly negative εNdt values (-7.9 and -7.8). These are a component of the Oxley volcanics. The ages of the Warraweena and Oxley volcanics are identical within uncertainty. The Oxley volcanics (OV) are interbedded with predominantly fine- to medium-grained metasedimentary and so imply a Lower Devonian deposition age for these host rocks. Based on their geophysical characteristics, the metasediments are widely distributed. These metasedimentary rocks yield a wide range of maximum depositional ages, from Early Devonian to earliest Ordovician-latest Cambrian, similar to the Cobar Basin. The absence of complex fabric development typical of Ordovician supracrustal rocks in the region, and conformity with the OV where observable suggest the widespread sedimentation was synchronous with rift-related volcanism in the Early Devonian. Regionally, the WV is temporally, geochemically and isotopically (εNd values) similar to the calc-alkaline Louth Volcanics located over 100 km to the southwest of the WV. Louth Volcanics define a complexly folded belt in geophysical data. Other potentially correlative Early Devonian igneous rocks occur in the nearby Cobar Superbasin and elsewhere in the eastern Lachlan Orogen and are considered to represent the products of a post-orogenic, nascent continental back-arc rift system. [ABSTRACT FROM AUTHOR]

Re-evaluation of geochemical and geophysical datasets, and analysis of magmatic and detrital zircons from drill-core samples extracted from the Louth region of the southern Thomson Orogen (STO), augmented by limited field samples, has shown that two temporally and compositionally distinct igneous groups exist. The older Lower Devonian, calc-alkaline group corresponds to complexly folded, high-intensity curvilinear magnetic anomalies in the Louth region (Louth Volcanics) and are probable equivalents to Lower Devonian volcanics in the northern Lachlan Orogen. A younger Permo-Triassic alkaline assemblage forms part of an E-W corridor of diatremes that appears to relate to focussed lithospheric extension associated with the later stages of the Hunter-Bowen Orogeny in the New England Orogen. The alkaline group includes gabbros previously considered as Neoproterozoic, but all magmatic rocks, including alkaline basalts, contain an unusual number of xenocrystic zircons. The age spectra of the xenocrystic zircons mimic detrital zircons from Cobar Basin sedimentary rocks and/or underlying Ordovician turbidites, suggesting incorporation of upper crustal zircons into the alkaline basaltic magmas. A distinct difference of detrital zircon age spectra from central Thomson Orogen metasediments indicates the STO metasediments have greater affinities to the Lachlan Orogen, but both orogens probably began in the Early Ordovician during widespread backarc extension and deposition of turbidites in the Tasmanides. A surprising result is that Ordovician, Devonian and Permo-Triassic basaltic rocks from the STO and elsewhere in the Tasmanides, all yield the same Nd-model ages of ca 960-830 Ma, suggesting that Neoproterozoic subcontinental lithospheric mantle persisted throughout the evolution of the Tasmanide orogenic system. [ABSTRACT FROM AUTHOR]

Sexual offending is a public health concern and societal risk requiring a multidisciplinary approach. While current data give an indication of the frequency of sexual victimization, these figures likely underestimate the severity of the concern as many of these incidents go unreported. And while sex offender research has increased over the past several decades, particular attention to those offenders with severe mental illness remains limited. In this descriptive review, literature describing sex offenders with psychotic disorders is explored with a focus on recent research. Important considerations are described, including theories surrounding psychosis and sexual offending, hospitalization rates, recidivism, not guilty by reason of insanity (NGRI), female offenders, and treatment considerations. By exploring these important aspects of sex offenders with psychosis, conclusions are drawn and future directions are proposed, with a particular emphasis on clinical application for the mental health treatment provider. [ABSTRACT FROM AUTHOR]

Sexual offending is a public health concern and societal risk requiring a multi-disciplinary approach. While current data give an indication of the frequency of sexual victimization, these figures likely underestimate the severity of the concern as many of these incidents go unreported. And while sex offender research has increased over the past several decades, particular attention to those offenders with severe mental illness remains limited. In this descriptive review, literature describing sex offenders with psychotic disorders is explored with a focus on recent research. Important considerations are described, including theories surrounding psychosis and sexual offending, hospitalization rates, recidivism, not guilty by reason of insanity (NGRI), female offenders, and treatment considerations. By exploring these important aspects of sex offenders with psychosis, conclusions are drawn and future directions are proposed, with a particular emphasis on clinical application for the mental health treatment provider. [ABSTRACT FROM AUTHOR]

Objective: to examine demand for emergency ambulances by older people. Design: retrospective cohort study using secondary analysis of routinely collected clinical and administrative data from Ambulance Victoria, and population data from the Australian Bureau of Statistics and the Australian Institute of Health and Welfare. Setting: Victoria, Australia. Participants: people aged 65 years and over, living in Residential Aged Care Facilities (RACF) and the community, attended by emergency ambulance paramedics, 2009-13. Main outcome measures: rates of emergency ambulance attendance. Results: older people living in RACF experienced high rates of emergency ambulance attendance, up to four times those for age- and sex-matched people living in the community. Rates remained constant during the study period equating to a consistent, 1.45% average annual increase in absolute demand. Rates peak among the 80-84-year group where the number of attendances equates to greater than one for every RACF-dwelling person each year. Increased demand was associated with winter months, increasing age and being male. Conclusion: these data provide strong evidence of high rates of emergency ambulance use by people aged 65 years and over living in RACF. These results demonstrate a clear relationship between increased rate of ambulance use among this vul- nerable group of older Australians and residence, sex, age and season. Overall, absolute demand continues to increase each year adding to strain on health resources. Additional research is needed to elucidate individual characteristics, illness and health system contributors to ambulance use to inform strategies to appropriately reduce demand. [ABSTRACT FROM AUTHOR]

In the realm of sexual offenses, there has been a decrease in hands-on offenses, but an increase in online offenses against children. The current issue is whether online and offline sexual offenders are alike or differ. This literature review investigates the differences among individuals who have committed child pornography offenses, individuals who have committed contact offenses against children, and individuals who have committed both. This review discusses the various typologies that have been proposed of those who have committed online offenses against children, the diagnostic implications of having committed child pornography offenses, and the current state of treatment and prevention of individuals who have committed online sex offenses against children. The studies examined were found from psychology databases, listserv links, and references of those collected articles. Only articles in English were included in the review. Overall, Internet child pornography offenders (ICPOs) tend to score significantly differently from contact offenders on various psychological measures. These findings may imply that ICPOs have different treatment needs than contact offenders. [ABSTRACT FROM AUTHOR]

Preserving large carnivores that perceive humans as prey brings conservation values into direct conflict with human security. Informing when and where humans and large carnivores occupy the same space may reduce attack frequency and promote coexistence. Here, we demonstrate a methodology to better understand the spatiotemporal relationship between a population of large carnivores and humans. The carnivore of study was the estuarine crocodile C rocodylus porosus, a large semi-aquatic predator responsible for 705 recorded human attacks over the last 20 years. Crocodiles were captured every August over 3 years and individuals greater than 2.5 m in length were implanted with an acoustic transmitter ( n = 84). The transmitter emitted a coded pulse detected when in proximity to underwater hydrophones deployed throughout the river. The telemetry data informed which previously captured crocodiles were present during subsequent trapping episodes and adult population size was estimated using a closed-population model. Over 3 years, 24 of the tagged crocodiles were detected 269 times moving through a shallow-water area where humans frequently entered the water. The tagged crocodile presence was extrapolated to the population level to provide a probability of adult crocodile presence across a range of temporal scales. The results showed that between September and December, the probability of crocodile presence within the human entry zone was 0.97 ± 0.01 during darkness but decreased to 0.07 ± 0.01 during daylight, except around periods of high tide when it increased to 0.71 ± 0.02. Human visitors confined their activity to shallow water during daylight hours, but no consideration was given to the significant rise in crocodile presence with season and tide. The observed patterns in crocodile and human behaviour, around this shallow-water river crossing, exhibited parallels with historical incidences of crocodile attack. [ABSTRACT FROM AUTHOR]

Abstract: Background: In China an estimated 780,000 people are living with HIV (PLWH). In high-income countries PLWH are at increased risk of depression, with subsequent adverse consequences for quality of life, and HIV-related morbidity and mortality. There are few data from low-and middle-income countries. The aims of this country-specific investigation of the Asia Pacific NeuroAIDS Consortium (APNAC) study were to establish the point prevalence, severity and HIV-related and non-HIV related correlates of depressive symptoms in PLWH, in Beijing, China. Method: PLWH attending an outpatient clinic at Ditan Hospital, Beijing were recruited consecutively. Data sources were: study-specific questions about demographic characteristics, and health behaviours, the Centre for Epidemiological Studies Depression Scale (CES-D), the World Health Organisation Self-Reporting Questionnaire (SRQ-20) translated into Mandarin and administered as structured individual interviews, and a screen battery of four standard neuropsychological tests. Results: In total 50/51 (98%) eligible patients agreed to participate. Overall 28% scored CES-D≥16 or SRQ20≥10 and 18% in these clinical ranges on both measures; 69% were classified as being neuropsychologically impaired (scoring below 1 SD of the control value on at least two tests). Higher depressive symptom scores were associated with lower education, alcohol overuse and diminished motor ability (all p<0.05), but not neuropsychological impairment Conclusion: Clinically significant depressive symptoms among this cohort of PLWH in Beijing occurred at 5 times the rate reported among a general Chinese urban population. No participants had been assessed for depression prior to the study and none were treated, indicating that consideration of psychological morbidity and its consequences for health behaviours should be incorporated into routine HIV care in China. [Copyright &y& Elsevier]

Vascular cognitive impairment (VCI), including vascular dementia, is the second most common dementia after Alzheimer's disease. Despite its prevalence, the genetic etiology of sporadic VCI is largely unknown. We conducted a systematic review of all published genetic association studies of forms of sporadic VCI prior to 6 July 2012. An initial pool of 229 gene association studies yielded 104 papers (72 polymorphisms from 47 genes) that met inclusion criteria for analysis. Systematic meta-analysis was conducted on 6 polymorphisms (which had 3 or more published case-control cohorts from 69 papers) in the APOE, ACT, ACE, MTHFR, PON1, and PSEN-1 genes. Associations of increased risk for VCI were found for APOE ε4 (1.818 (95% CI = 1.611-2.053), p < 0.001; n = 3,554 cases, n = 12,277 controls) and MTHFR rs1801133 (1.323 (95% CI = 1.061-1.650) p = 0.013); n = 659 cases, n = 981 controls). There was marginal evidence of a protective effect for APOE ε2 (0.885 (95% CI = 0.783-0.999), p = 0.048; n = 3,320 cases, n = 10,786 controls). This systematic study of all published genetic association studies of sporadic VCI supports MTHFR and APOE as susceptibility genes for VCI. It also shows the utility of meta-analysis as a tool to identify potential candidate genes from numerous individual small-scale studies of diseases where sample recruitment may be limited for a variety of practical reasons. [ABSTRACT FROM AUTHOR]