Medical Library

This departmental history was written on the occasion of the UND Centennial in 1983.https://commons.und.edu/departmental-histories/1039/thumbnail.jp

Localisation of gamma-ray interaction points in thick monolithic CeBr3 and LaBr3:Ce scintillators

Localisation of gamma-ray interaction points in monolithic scintillator crystals can simplify the design and improve the performance of a future Compton telescope for gamma-ray astronomy. In this paper we compare the position resolution of three monolithic scintillators: a 28x28x20 mm3 (length x breadth x thickness) LaBr3:Ce crystal, a 25x25x20 mm3 CeBr3 crystal and a 25x25x10 mm3 CeBr3 crystal. Each crystal was encapsulated and coupled to an array of 4x4 silicon photomultipliers through an optical window. The measurements were conducted using 81 keV and 356 keV gamma-rays from a collimated 133Ba source. The 3D position reconstruction of interaction points was performed using artificial neural networks trained with experimental data. Although the position resolution was significantly better for the thinner crystal, the 20 mm thick CeBr3 crystal showed an acceptable resolution of about 5.4 mm FWHM for the x and y coordinates, and 7.8 mm FWHM for the z-coordinate (crystal depth) at 356 keV. These values were obtained from the full position scans of the crystal sides. The position resolution of the LaBr3:Ce crystal was found to be considerably worse, presumably due to the highly diffusive optical in- terface between the crystal and the optical window of the enclosure. The energy resolution (FWHM) measured for 662 keV gamma-rays was 4.0% for LaBr3:Ce and 5.5% for CeBr3. The same crystals equipped with a PMT (Hamamatsu R6322-100) gave an energy resolution of 3.0% and 4.7%, respectively

Female undergraduate\u27s perceptions of intrusive behavior in 12 countries

The present study examines young women\u27s (N = 1,734) perceptions of the unacceptability of 47 intrusive activities enacted by men. Female undergraduate psychology students from 12 countries (Armenia, Australia, England, Egypt, Finland, India, Indonesia, Italy, Japan, Portugal, Scotland, Trinidad) indicated which of 47 intrusive activities they considered to be unacceptable. Responses were compared with parasite-stress values, a measure of global gender equality and Hofstede\u27s dimensions of national cultures. There was no unanimous agreement on any of the items, even for those relating to forced sexual violence. Cluster analysis yielded four clusters: “Aggression and surveillance” (most agreement that the constituent items were unacceptable), “Unwanted attention,” “Persistent courtship and impositions,” and “Courtship and information seeking” (least agreement that the constituent items were unacceptable). There were no significant relationships between the “Aggression and surveillance” or “Courtship and information seeking” clusters and the measure of gender equality, Hofstede\u27s dimensions of national cultures or the measure of parasite stress. For the “Unwanted attention” and “Persistent courtship and impositions” clusters, women residing in countries with higher gender inequality and higher parasite-stress were less accepting of behavior associated with uncommitted sexual relations, and women in more individualistic societies with higher levels of gender equality were less accepting of monitoring activities. Culture may take precedence over personal interpretations of the unacceptability of intrusive behavior that is not obviously harmful or benign in nature

Twelve (not so) angry men: jurors work better in small groups. Lorraine Hope and Bridget Waller propose a simple modification to jury deliberations

Twelve-person juries are often regarded as one of the cornerstones of democracy. In the UK, the right to a trial by jury is considered an important feature of the criminal justice system. Indeed, it has been rated as more important than a number of other rights, including the right to protest against the government, the right not to be detained for an extended period without charge and the right to free speech in public (Roberts and Hough, 2009). The public also trusts juries comprising randomly selected ordinary people and relies on the contribution of 12 individuals to eliminate bias and prejudice from the decision making process

Parenting in Adversity: Effects of Older Caregivers, Biological Carers and Troubled Carers on Child Outcomes in High HIV-Affected Communities

Caregiving by older adults is a common phenomenon, enhanced in the era of HIV infection. This longitudinal study was set up to examine the effect of caregiver age, relationship and mental wellbeing on child (4-13 years) outcomes (psychosocial and cognitive) in a sample of 808 caregiver- child dyads in South Africa and Malawi. Respondents were drawn from consecutive attenders at Community Based Organisations (CBOs) and interviewed with standardised inventories at baseline and followed up 12-15 months later. Analysis focused on three separate aspects of the caregiver; age, relationship to the child, and mental wellbeing, results are stratified with regard to these factors. Results showed that compared to younger caregivers, over 50 years were carrying a heavy load of childcare, but caregiver age for the most part was not associated with child outcomes. Being biologically related to the child (such as biological grandparenting) was also not a significant factor in child outcomes measured. However, irrespective of age and relationship, caregiver mental health was associated with differences in child outcome - those children of caregivers with a greater mental health burden were found to report experiencing more physical and psychologically violent discipline. Over time, the use of violent discipline was found to reduce. These data suggest that older caregivers and grandparents are providing comparable care to younger caregivers, for young children in the face of the HIV epidemic and that interventions should focus on mental health support for all caregivers, irrespective of age or relationship to the child

Adolescent parenthood and HIV-infection in South Africa—Associations with child cognitive development

HIV, both directly and indirectly, impacts child development outcomes. The most severe impacts are for children infected with HIV, and those exposed but uninfected are also shown to have challenges-though less severe. However, little is known regarding the development of children born to adolescent mothers affected by HIV. This study aims to examine cognitive development for children born to adolescent mothers, comparing those children living with HIV, those HIV exposed and uninfected (HEU) and those HIV unexposed (HU). Analyses utilise cross-sectional data from 920 adolescent mother (10-19 years)-first born child dyads residing in the Eastern Cape Province, South Africa. Participants completed detailed study questionnaires inclusive of validated and study specific measures relating to sociodemographic characteristics, HIV, and maternal and child health. Trained assessors administered standardised child development assessments (using the Mullen Scales of Early Learning) with all children. Chi-square tests and ANOVA tests were used to explore maternal and child characteristics according to child HIV status (HIV, HEU, HU) on cognitive development. Linear regression models were used to explore the cross-sectional associations between child HIV status and child cognitive development. 1.2% of children were living with HIV, 20.5% were classified as being HEU and, 78.3% were classified as HU. Overall, children living with HIV were found to perform lower across developmental domains compared to both HEU and HU groups (composite score of early learning: 73.0 vs 91.2 vs. 94.1, respectively: F = 6.45, p = 0.001). HEU children on average scored lower on all developmental domains compared to HU children, reaching significance on the gross motor domain (p<0.05). Exploratory analyses identified maternal education interruption as a potential risk factor for lower child cognitive development scores and, higher maternal age to be protective of child cognitive development scores. These exploratory findings address a critical evidence gap regarding the cognitive development of children born to adolescent mothers affected by HIV in South Africa. Analyses identify stepwise differences in the average scoring on child cognitive development domains according to child HIV status among children born to adolescent mothers affected by HIV; with children living with HIV performing worse overall. Young mothers and their children may benefit from adapted interventions aimed at bolstering child development outcomes. Targeted programming particularly among younger adolescent mothers and those experiencing education interruption may identify those families, particularly in need. Attention to maternal continuity of education and age of conception may be interventions to consider

Protocol for the OCAY study: a cohort study of orphanhood and caregiver loss in the COVID-19 era to explore the impact on children and adolescents

INTRODUCTION: Globally, no person has been untouched by the COVID-19 pandemic. Yet, little attention has been given to children and adolescents in policy, provision and services. Moreover, there is a dearth of knowledge regarding the impact of COVID-19-associated orphanhood and caregiver loss on children. This study aims to provide early insights into the mental health and well-being of children and adolescents experiencing orphanhood or caregiver loss in South Africa. METHODS AND ANALYSIS: Data will be drawn from a quantitative longitudinal study in Cape Town, South Africa. A sample of children and adolescents between the ages of 9 and 18 years, experiencing parental or caregiver loss from COVID-19, will be recruited together with a comparison group of children in similar environments who did not experience loss. The study aims to recruit 500 children in both groups. Mental health and well-being among children will be explored through the use of validated and study-specific measures. Participants will be interviewed at two time points, with follow-up data being collected 12-18 months after baseline. A combination of analytical techniques (including descriptive statistics, regression modelling and structural equation modelling) will be used to understand the experience and inform future policy and service provision. ETHICS AND DISSEMINATION: This study received ethical approval from the Health Research Ethics Committee at Stellenbosch University (N 22/04/040). Results will be disseminated via academic and policy publications, as well as national and international presentations including high-level meetings with technical experts. Findings will also be disseminated at a community level via various platforms

Associations of formal childcare use with health and human capital development for adolescent mothers and their children in South Africa: A cross-sectional study

AIM: This study aims to investigate associations of formal childcare with maternal and child outcomes in a large sample of adolescent mothers. BACKGROUND: Forty percent of adolescent girls in Africa are mothers. Increasing evidence shows positive impacts of formal childcare use for adult women, but no known studies in the Global South examine associations for adolescent mothers and their children. METHODS: We interviewed 1046 adolescent mothers and completed developmental assessments with their children (n = 1139) in South Africa's Eastern Cape between 2017 and 2019. Questionnaires measured childcare use, maternal and child outcomes and socio-demographic background variables. Using cross-sectional data, associations between formal childcare use and outcomes were estimated in multivariate multi-level analyses that accounted for individual-level and family-level clustering. RESULTS: Childcare use was associated with higher odds of being in education or employment (AOR: 4.01, 95% CIs: 2.59-6.21, p < .001), grade promotion (AOR: 2.08, 95% CIs: 1.42-3.05, p < .001) and positive future ideation (AOR: 1.58, 95% CIs: 1.01-2.49, p = .047) but no differences in mental health. Childcare use was also associated with better parenting on all measures: positive parenting (AOR: 1.66, 95% CIs: 1.16-2.38, p = .006), better parental limit-setting (AOR: 2.00, 95% CIs: 1.37-2.93, p < .001) and better positive discipline (AOR: 1.77, 95% CIs: 1.21-2.59, p = .003). For the children, there were no differences in temperament or illness, but a significant interaction showed stronger associations between childcare use and better cognitive, language and motor scores with increasing child age (AOR: 5.04, 95% CIs: 1.59-15.96, p = .006). CONCLUSIONS: Adolescent mothers might benefit substantially from formal childcare, but causal links need to be explored further. Childcare use was also associated with improved parenting and better child development over time, suggesting positive pathways for children. At an average of $9 per month, childcare provisions for adolescent mothers may offer low-cost opportunities to achieve high returns on health and human capital outcomes in Sub-Saharan African contexts

Surface and subsurface manifestations of gas movement through a N–S transect of the Gulf of Mexico

Author Posting. © The Authors, 2004. This is the author's version of the work. It is posted here by permission of Elsevier B. V. for personal use, not for redistribution. The definitive version was published in Marine and Petroleum Geology 22 (2005): 479-497, doi:10.1016/j.marpetgeo.2004.08.008.Large volumes of gas have vented through a north-south transect of the offshore northern Gulf of Mexico. An overview of surface and subsurface manifestations of this gas venting is presented. This gas movement has caused extensive alteration of reservoired oils to the north of the transect which are estimated to have equilibrated with, or been gas washed by, as much as 30 volumes of gas for every volume of oil. This gas washing entrains and carries upward the most volatile oil components depositing them in either shallower reservoirs or venting them to the overlying sediments and the water column. A significant amount of this gas bypasses the reservoirs and vents upward into the overlying sediments and waters. In spite of the significant amounts of the gas involved, the venting at the seafloor appears to occur primarily through highly localized faults and fractures. This gas discharge is spatially and temporally heterogeneous, making it difficult to estimate the actual hydrocarbon fluxes involved. This upward gas movement leaves characteristic signatures at the sediment water interface including carbonate pavements in older seep areas, and chemosynthetic biological communities, methane hydrates, and gas seeps in more recent long-term seep areas. In some cases where gas venting is very recent, massive disruption of surface and subsurface sediments is observed to be occasionally accompanied by mud volcanoes. Venting can be vigorous enough to produce methane gas bubbles, which appear to be injected rapidly into surface waters and which may constitute a significant source of methane, a greenhouse gas, to the atmosphere. In the northern Gulf of Mexico, gas venting is sometimes accompanied by natural oil slicks at the sea surface, which can be tracked for many miles in non-productive areas. These gas-venting signatures are not unique to the Gulf of Mexico; similar seep features are observed in sediments worldwide. The widespread occurrence of these seep features, which may or may not be related to subsurface oil and gas deposits, may explain why use of surface seeps has often proved to be so controversial in oil exploration. Indeed, most seeps are probably not linked with economic subsurface petroleum reservoirs. The relationships between surface seep features and productive subsurface reservoirs along a N-S transect of the Northern Gulf of Mexico are presented as an example of how all surface and subsurface geochemical, geological, geophysical data might be used together to better constrain interpretations regarding the nature and dynamics of subsurface oil and gas deposits and their plumbing in frontier areas.Support for this work was provided by the Department of Energy, Grant No. DE-FG02-86EF13466 and U.S. Department of Energy Grant No. DE-FC26-00NT40920 through the University of Mississippi to Jean Whelan and; Gas Research Institute Contract GRI50972603787 to Larry Cathles, Cornell University with a subcontract to Jean Whelan