Assessment of the recreational linefishery in selected Eastern Cape estuaries: trends in catches and effort

Boat-based creel surveys were used to collect catch and effort data on the shore- and boat-based linefisheries of the Kromme, Gamtoos, Swartkops, Sundays, Bushmans, Kariega, Kowie and Great Fish estuaries in the Eastern Cape, South Africa, from January 1996 to April 1997. The surveys, which were performed primarily during routine fisheries law enforcement patrols by a regional conservation agency, recorded the catch and effort of 2 468 individual angler outings (12 840 angling hours) during 337 angler-count patrols. Although 26 species were recorded, a large proportion of the catch (85%) comprised only four species. Spotted grunter Pomadasys commersonnii (43%) was most commonly caught, followed by Cape stumpnose Rhabdosargus holubi (16%), dusky kob Argyrosomus japonicus (14%) and white seacatfish Galeichthys feliceps (12%). In terms of mass, the overall catch was dominated by A. japonicus (50%) and P. commersonnii (33%). Overall catch per unit effort (cpue) by number was highest during summer and lowest during winter, and vice versa for cpue according to mass. Angler counts showed the Sundays Estuary had the highest mean angling effort for both weekdays and weekends (10.1 and 22.9 anglers count-1 respectively). The Gamtoos Estuary had the lowest count for weekdays (5.5 anglers count-1) and the Kariega Estuary the lowest for weekends (9.8 anglers count-1). Shore-based was more popular than boat-based angling (59% compared to 41%), and all estuaries had substantially higher angling effort on weekends than on weekdays. Angling with bait (93.3%) was more popular than lure- or fly-angling (6.7% combined). Considerations for management of A. japonicus in the Eastern Cape estuarine linefishery are presented.Keywords: catches, Eastern Cape, effort, estuaries, recreational linefisheryAfrican Journal of Marine Science 2002, 24: 87–10

Characterising and Testing Deep UV LEDs for Use in Space Applications

Deep ultraviolet (DUV) light sources are used to neutralise isolated test masses in highly sensitive space-based gravitational experiments. An example is the LISA Pathfinder charge management system, which uses low-pressure mercury lamps. A future gravitational-wave observatory such as eLISA will use UV light-emitting diodes (UV LEDs), which offer numerous advantages over traditional discharge lamps. Such devices have limited space heritage but are are now available from a number of commercial suppliers. Here we report on a test campaign that was carried out to quantify the general properties of three types of commercially available UV LEDs and demonstrate their suitability for use in space. Testing included general electrical and UV output measurements, spectral stability, pulsed performance, temperature dependence as well as thermal vacuum, radiation and vibration survivability

Novel methods to measure the gravitational constant in space

We present two novel methods, tested by LISA Pathfinder, to measure the gravitational constant G for the first time in space. Experiment 1 uses electrostatic suspension forces to measure a change in acceleration of a test mass due to a displaced source mass. Experiment 2 measures a change in relative acceleration between two test masses due to a slowly varying fuel tank mass. Experiment 1 gave a value of G=6.71±0.42(×10-11)¿¿m3¿s-2¿kg-1 and experiment 2 gave 6.15±0.35(×10-11)¿¿m3¿s-2¿kg-1, both consistent with each other to 1s and with the CODATA 2014 recommended value of 6.67408±0.00031(×10-11)¿¿m3¿s-2¿kg-1 to 2s. We outline several ideas to improve the results for a future experiment, and we suggest that a measurement in space would isolate many terrestrial issues that could be responsible for the inconsistencies between recent measurements.Peer ReviewedPostprint (published version

LISA pathfinder micronewton cold gas thrusters: in-flight characterization

The LISA Pathfinder (LPF) mission has demonstrated the ability to limit and measure the fluctuations in acceleration between two free falling test masses down to sub-femto-g levels. One of the key elements to achieve such a level of residual acceleration is the drag free control. In this scheme the spacecraft is used as a shield against any external disturbances by adjusting its relative position to a reference test mass. The actuators used to move the spacecraft are cold gas micropropulsion thrusters. In this paper, we report in-flight characterization of these thrusters in term of noise and artefacts during science operations using all the metrology capabilities of LISA Pathfinder. Using the LISA Pathfinder test masses as an inertial reference frame, an average thruster noise of ~0.17¿¿µN/Hz is observed and decomposed into a common (coherent) and an uncorrelated component. The very low noise and stability of the onboard metrology system associated with the quietness of the space environment allowed the measurement of the thruster noise down to ~20¿¿µHz, more than an order of magnitude below any ground measurement. Spectral lines were observed around ~1.5¿¿mHz and its harmonics and around 55 and 70 mHz. They are associated with the cold gas system itself and possibly to a clock synchronization issue. The thruster noise-floor exhibits an excess of ~70% compared to characterization that have been made on ground on a single unit and without the feeding system. However this small excess has no impact on the LPF mission performance and is compatible with the noise budget for the upcoming LISA gravitational wave observatory. Over the whole mission, nominal, and extension, the thrusters showed remarkable stability for both the science operations and the different maneuvers necessary to maintain LPF on its orbit around L1. It is therefore concluded that a similar cold gas system would be a viable propulsion system for the future LISA mission.Peer ReviewedPostprint (author's final draft

Temperature stability in the sub-milliHertz band with LISA Pathfinder

This article has been accepted for publication in "Monthly notices of the royal astronomical society" published by Oxford University Press.LISA Pathfinder (LPF) was a technology pioneering mission designed to test key technologies required for gravitational wave detection in space. In the low frequency regime (milliHertz and below), where space-based gravitational wave observatories will operate, temperature fluctuations play a crucial role since they can couple into the interferometric measurement and the test masses’ free-fall accuracy in many ways. A dedicated temperature measurement subsystem, with noise levels in 10¿µK¿Hz-1/2 down to 1¿mHz was part of the diagnostics unit onboard LPF. In this paper we report on the temperature measurements throughout mission operations, characterize the thermal environment, estimate transfer functions between different locations, and report temperature stability (and its time evolution) at frequencies as low as 10¿µHz, where typically values around 1¿K¿Hz-1/2 were measured.Peer ReviewedPreprin

Antenatal-Based Pilot Psychosocial Intervention to Enhance Mental Health of Pregnant Women Experiencing Domestic and Family Violence in Nepal.

Survivors of domestic and family violence (DFV) report poorer quality of life and worsening mental health. This study evaluated the effect of a counseling and education intervention on the mental health and help-seeking behaviors among pregnant women living with DFV. A parallel pilot randomized controlled trial was performed among 140 pregnant women attending an antenatal clinic of a tertiary hospital of Nepal. Using computer-generated random numbers, participants were randomized to the intervention group (a counseling session, an information booklet about DFV, and contact details of the counselor) or a control group (usual care plus a booklet containing contact details of local DFV support services). Outcome measures included mental health, quality of life (QOL), self-efficacy, social support, and safety planning behaviors. Analyses followed intention-to-treat, using the generalized estimating equation model. Intervention participants showed significant improvements in anxiety (β = -3.24, p < .001) and depression (β = -3.16, p < .001) at postintervention. Such improvements were also sustained at follow-up assessment (p < .001). Significant group and time interaction for QOL, social support, use of safety behaviors, and self-efficacy (p < .05) revealed a greater increase in these outcome measures among intervention participants at both follow-up assessments compared with the control group. This pilot integrated intervention showed promising outcomes in improving the mental health, social support, and the use of safety behaviors among women with DFV. This intervention could be incorporated into regular antenatal care as a strategy to identify and support victims of DFV. Larger controlled trials with longer follow-up are needed to support and expand on the current findings regarding the effectiveness of a psychosocial intervention targeting victims of DFV in resource-constrained settings

Sr0.9_{0.9}K0.1_{0.1}Zn1.8_{1.8}Mn0.2_{0.2}As2_{2}: a ferromagnetic semiconductor with colossal magnetoresistance

A bulk diluted magnetic semiconductor (Sr,K)(Zn,Mn)$_{2}$As$_{2}$ was synthesized with decoupled charge and spin doping. It has a hexagonal CaAl$_{2}$Si$_{2}$-type structure with the (Zn,Mn)$_{2}$As$_{2}$ layer forming a honeycomb-like network. Magnetization measurements show that the sample undergoes a ferromagnetic transition with a Curie temperature of 12 K and \revision{magnetic moment reaches about 1.5 $\mu_{B}$/Mn under $\mu_0H$ = 5 T and $T$ = 2 K}. Surprisingly, a colossal negative magnetoresistance, defined as $[\rho(H)-\rho(0)]/\rho(0)$, up to $-$38\% under a low field of $\mu_0H$ = 0.1 T and to $-$99.8\% under $\mu_0H$ = 5 T, was observed at $T$ = 2 K. The colossal magnetoresistance can be explained based on the Anderson localization theory.Comment: Accepted for publication in EP

'We don't see because we don't ask': Qualitative exploration of service users' and health professionals' views regarding a psychosocial intervention targeting pregnant women experiencing domestic and family violence.

INTRODUCTION:Given the relative recency of Domestic and Family Violence (DFV) management as a field of endeavour, it is not surprising that interventions for addressing DFV is still in its infancy in developing countries. In order to maximise the success of an intervention, it is important to know which aspects of the intervention are considered important and helpful by service providers and service users. This study, therefore, examined the acceptability of an antenatal-based psychosocial intervention targeting DFV in Nepal and explored suggestions for improving the program in future. MATERIALS AND METHODS:Intervention participants and health care providers (HCPs) were interviewed using semi-structured interviews. Data were audio-recorded and thematic analysis was used to analyse the data. Final codes and themes were identified using an iterative review process among the research team. RESULTS:Themes emerging from the data were grouped into domains including perceptions towards DFV, impact of the intervention on women's lives and recommendations for improving the program. DFV was recognised as a significant problem requiring urgent attention for its prevention and control. Intervention participants expressed that they felt safe to share their feelings during the counselling session and got opportunity to learn new skills to cope with DFV. The majority of the participants recommended multiple counselling sessions and a continued provision of the service ensuring the intervention's accessibility by a large number of women. DISCUSSION:This is the first study to document the perspectives of women and HCPs regarding an antenatal-based intervention targeting psychosocial consequences of DFV in Nepal. There was a clear consensus around the need to engage, support and empower victims of DFV and the intervention was well received by the participants. Ensuring good mental health and wellbeing among victims of DFV requires work across individual, organisational and community levels

Counselling-based psychosocial intervention to improve the mental health of abused pregnant women: A protocol for randomised controlled feasibility trial in a tertiary hospital in eastern Nepal

© 2019 Author(s). Published by BMJ. Introduction The strong correlation between domestic and family violence (DFV) and mental health has been well documented in studies. Pregnancy is a period when both DFV and mental distress tend to occur and/or accentuate. Although limited, available evidence from developed countries has shown continual support and education as psychological first aid that can reduce DFV and improve mental health. However, there is significantly less number of studies from resource-constrained countries; thus, there continues to be a substantial gap in knowledge and awareness regarding effective interventions for DFV. Methods and analysis A two-arm randomised trial with a nested qualitative study has been planned to assess feasibility and treatment effect estimates of a counselling-based psychosocial intervention among pregnant women with a history of abuse. A total of 140 pregnant women who meet the inclusion criteria will be recruited into the study. Block randomisation will be used to allocate women equally into two groups. The intervention group will receive a counselling session, an information booklet and continuous support by a researcher, while women in the control group will receive contact information of local support services. Feasibility measures, such as rates of recruitment, consent and retention, will be calculated. Qualitative interviews with participants and healthcare providers will explore the acceptability and usability of the intervention. Outcome measures, such as psychological distress, quality of life, social support and self-efficacy, will be measured at baseline, 4 weeks postintervention and 6 weeks postpartum. Ethics and dissemination This study has obtained ethical approval from the Griffith University Human Research Ethics Committee, the Nepal Health Research Council and the Institutional Review Board of a tertiary hospital in Dharan, Nepal. The findings will be disseminated via peer-reviewed publications and conference presentations and will be used to inform a future multicentre trial