Prevalence and correlates of violence among South African high school learners in uMgungundlovu District municipality, KwaZulu-Natal, South Africa

Background. Young people grow up in homes and communities where many are exposed daily to crime and antisocial behaviours.Objective. To investigate the prevalence of violence and the demographic factors associated with such violence among South African (SA) high school learners in the uMgungundlovu District, KwaZulu-Natal, SA.Methods. In a cross-sectional study, we used stratified random sampling to select 16 schools in uMgungundlovu District. All Grade 10 high school learners (N=1 741) completed a self-administered questionnaire (Centers for Disease Control Youth Risk Behavior Survey). Data analysis was carried out using STATA 13 statistical software (Statacorp, USA).Results. Of the participants in this study, 420 (23.9%) had been bullied, 379 (21.7%) had missed school because of feeling unsafe, 468 (15.4%) had been involved in physical fights and 41 (2.4%) had carried weapons to school. There was a significant association between being in a physical fight and missing school (odds ratio (OR) 2.5, 95% confidence interval (CI) 1.9 - 3.3; p<0.001). There were higher odds of male learners carrying weapons than female learners (OR 5.9, 95% CI 2.0 - 15.0). Among learners living in rented rooms, the OR of feeling unsafe was 2.7 (95% CI 0.8 - 3.0), in an informal settlement the OR was 0.8 (95% CI 0.3 - 2.0) and in reconstruction and development programme houses it was 2.7 (95% CI 1.0 - 5.0), compared with learners residing in Zulu homesteads.Conclusion. Violence among learners attending high schools in uMgungundlovu District is a major problem and has consequences for both their academic and social lives. Urgent interventions are required to reduce the rates of violence among high school learners

Microwave monolithic integrated circuit development for future spaceborne phased array antennas

The development of fully monolithic gallium arsenide (GaAs) receive and transmit modules suitable for phased array antenna applications in the 30/20 gigahertz bands is presented. Specifications and various design approaches to achieve the design goals are described. Initial design and performance of submodules and associated active and passive components are presented. A tradeoff study summary is presented highlighting the advantages of distributed amplifier approach compared to the conventional single power source designs

High-power AlGaAs channeled substrate planar diode lasers for spaceborne communications

A high power channeled substrate planar AlGaAs diode laser with an emission wavelength of 8600 to 8800 A was developed. The optoelectronic behavior (power current, single spatial and spectral behavior, far field characteristics, modulation, and astigmatism properties) and results of computer modeling studies on the performance of the laser are discussed. Lifetest data on these devices at high output power levels is also included. In addition, a new type of channeled substrate planar laser utilizing a Bragg grating to stabilize the longitudinal mode was demonstrated. The fabrication procedures and optoelectronic properties of this new diode laser are described

CoSMoMVPA: Multi-Modal Multivariate Pattern Analysis of Neuroimaging Data in Matlab/GNU Octave

Recent years have seen an increase in the popularity of multivariate pattern (MVP) analysis of functional magnetic resonance (fMRI) data, and, to a much lesser extent, magneto- and electro-encephalography (M/EEG) data. We present CoSMoMVPA, a lightweight MVPA (MVP analysis) toolbox implemented in the intersection of the Matlab and GNU Octave languages, that treats both fMRI and M/EEG data as first-class citizens. CoSMoMVPA supports all state-of-the-art MVP analysis techniques, including searchlight analyses, classification, correlations, representational similarity analysis, and the time generalization method. These can be used to address both data-driven and hypothesis-driven questions about neural organization and representations, both within and across: space, time, frequency bands, neuroimaging modalities, individuals, and species. It uses a uniform data representation of fMRI data in the volume or on the surface, and of M/EEG data at the sensor and source level. Through various external toolboxes, it directly supports reading and writing a variety of fMRI and M/EEG neuroimaging formats, and, where applicable, can convert between them. As a result, it can be integrated readily in existing pipelines and used with existing preprocessed datasets. CoSMoMVPA overloads the traditional volumetric searchlight concept to support neighborhoods for M/EEG and surface-based fMRI data, which supports localization of multivariate effects of interest across space, time, and frequency dimensions. CoSMoMVPA also provides a generalized approach to multiple comparison correction across these dimensions using Threshold-Free Cluster Enhancement with state-of-the-art clustering and permutation techniques. CoSMoMVPA is highly modular and uses abstractions to provide a uniform interface for a variety of MVP measures. Typical analyses require a few lines of code, making it accessible to beginner users. At the same time, expert programmers can easily extend its functionality. CoSMoMVPA comes with extensive documentation, including a variety of runnable demonstration scripts and analysis exercises (with example data and solutions). It uses best software engineering practices including version control, distributed development, an automated test suite, and continuous integration testing. It can be used with the proprietary Matlab and the free GNU Octave software, and it complies with open source distribution platforms such as NeuroDebian. CoSMoMVPA is Free/Open Source Software under the permissive MIT license. Website: http://cosmomvpa.org Source code: https://github.com/CoSMoMVPA/CoSMoMVPA

Introduction of Multipurpose Tree Species for Improving the Productivity of Grasslands in the Tropics

To improve the productivity of the Sahelian pastures, 10 different tree species were introduced and cattle, sheep and goats were allowed to graze. After a year of establishment, survival rate of different species ranged from 6% to 68%. Acacia senegal, Acacia seyal, Acacia nilotica, Combretum aculeata and Prosopis cineraria performed well and the impact of browsing by goats was severe

Image Coaddition with Temporally Varying Kernels

Large, multi-frequency imaging surveys, such as the Large Synaptic Survey Telescope (LSST), need to do near-real time analysis of very large datasets. This raises a host of statistical and computational problems where standard methods do not work. In this paper, we study a proposed method for combining stacks of images into a single summary image, sometimes referred to as a template. This task is commonly referred to as image coaddition. In part, we focus on a method proposed in previous work, which outlines a procedure for combining stacks of images in an online fashion in the Fourier domain. We evaluate this method by comparing it to two straightforward methods through the use of various criteria and simulations. Note that the goal is not to propose these comparison methods for use in their own right, but to ensure that additional complexity also provides substantially improved performance

Prevalence and correlates of violence among South African high school learners in uMgungundlovu District municipality, KwaZulu-Natal, South Africa

Background. Young people grow up in homes and communities where many are exposed daily to crime and antisocial behaviours. Objective. To investigate the prevalence of violence and the demographic factors associated with such violence among South African (SA)high school learners in the uMgungundlovu District, KwaZulu-Natal, SA. Methods. In a cross-sectional study, we used stratified random sampling to select 16 schools in uMgungundlovu District. All Grade 10 high school learners (N=1 741) completed a self-administered questionnaire (Centers for Disease Control Youth Risk Behavior Survey). Data analysis was carried out using STATA 13 statistical software (Statacorp, USA).Results. Of the participants in this study, 420 (23.9%) had been bullied, 379 (21.7%) had missed school because of feeling unsafe, 468 (15.4%) had been involved in physical fights and 41 (2.4%) had carried weapons to school. There was a significant association between being in a physical fight and missing school (odds ratio (OR) 2.5, 95% confidence interval (CI) 1.9 - 3.3; p<0.001). There were higher odds of male learners carrying weapons than female learners (OR 5.9, 95% CI 2.0 - 15.0). Among learners living in rented rooms, the OR of feeling unsafe was 2.7 (95% CI 0.8 - 3.0), in an informal settlement the OR was 0.8 (95% CI 0.3 - 2.0) and in reconstruction and development programme houses it was 2.7 (95% CI 1.0 - 5.0), compared with learners residing in Zulu homesteads. Conclusion. Violence among learners attending high schools in uMgungundlovu District is a major problem and has consequences for both their academic and social lives. Urgent interventions are required to reduce the rates of violence among high school learners