Migration theories and Zimbabwean migrant teachers as reflected in a south african case study

Neo-classical and neo-Marxist theories oppose each other in terms of explaining motivation for migration and its development impact. Neo-classical theories posit that migration occurs because of economic considerations: higher incomes and economic gain. Neo-Marxist theories emphasize that migration occurs because of unequal and structural levels of development between developed and developing countries, regions or areas. In sub-Saharan Africa, South Africa is relatively economically developed compared to other countries in the region and, according to neo-Marxist philosophy, exploits the labour from other poorer countries. In this case study, the focus is on migrant teachers from Zimbabwe. According to neo-Marxist- theories, migrants exist in an exploitative relationship with their host regions and/or countries. Apart from neo-classical and neo-Marxist theories, pluralist theories have evolved from these distinctive schools of thought that emphasize that migration is the result of a conscious family decision aimed at diversifying their resource base when faced with crises and/or scarcity, asserting that migration does indeed bring about development. This paper contends that neo-classical theories do apply to the case of Zimbabwean migrant teachers because they satisfactorily explain why these teachers came to South Africa, whereas neo-Marxist theories have limited relevance. Pluralist theories, however, through their emphasis on remittances, add meaning to people’s motivations for, and the consequent impact of development related to this particular aspect of migration

TRAPPED IN A GARDEN OF GREENER PASTURES: THE EXPERIENCES OF ZIMBABWEAN TEACHERS IN SOUTH AFRICA

 Most immigrants from African countries choose Johannesburg as a migration destination. They all perceive it to be location with many opportunities that would enable them to make a fresh start to a life outside their home country, and Zimbabweans are no exception. In South Africa, Johannesburg has a large percentage of foreigners at any given time, hence its inner city was chosen as a suitable location to investigate the extent and manner in which the experiences of migrant Zimbabwean teachers matched their expectations. The results revealed a paradox of economic satisfaction accompanied by fear and social unhappiness in the lives of these Zimbabwean teachers in South Africa. The Zimbabwean migrant teachers have two juxta-positioned problematic situations: wanting the money, their initial reason for migrating and motivation to continue working; and feeling imprisoned, unsafe and unwanted, an incongruous reality, in South Africa. This paper examines the dynamics of these contradictions by presenting the two-pronged dilemma from both an economic and a social point of view. They want to be and not to be in South Africa at the same time – they are trapped in a contradictory existence, in a city and country to which they chose to migrate.

MIGRATION THEORIES AND ZIMBABWEAN MIGRANT TEACHERS AS REFLECTED IN A SOUTH AFRICAN CASE STUDY

Neo-classical and neo-Marxist theories oppose each other in terms of explaining motivation for migration and its development impact. Neo-classical theories posit that migration occurs because of economic considerations: higher incomes and economic gain. Neo-Marxist theories emphasize that migration occurs because of unequal and structural levels of development between developed and developing countries, regions or areas. In sub-Saharan Africa, South Africa is relatively economically developed compared to other countries in the region and, according to neo-Marxist philosophy, exploits the labour from other poorer countries. In this case study, the focus is on migrant teachers from Zimbabwe. According to neo-Marxist- theories, migrants exist in an exploitative relationship with their host regions and/or countries. Apart from neo-classical and neo-Marxist theories,  pluralist theories  have evolved from these distinctive schools of thought that emphasize that migration is the result of a conscious family decision aimed at diversifying their resource base when faced with crises and/or scarcity, asserting that migration does indeed bring about development. This paper contends that neo-classical theories do apply to the case of Zimbabwean migrant teachers because they satisfactorily explain why these teachers came to South Africa, whereas neo-Marxist theories have limited relevance. Pluralist theories, however, through their emphasis on remittances, add meaning to people’s motivations for, and the consequent impact of development related to this particular aspect of migration

Testing gravitational-wave searches with numerical relativity waveforms: Results from the first Numerical INJection Analysis (NINJA) project

The Numerical INJection Analysis (NINJA) project is a collaborative effort between members of the numerical relativity and gravitational-wave data analysis communities. The purpose of NINJA is to study the sensitivity of existing gravitational-wave search algorithms using numerically generated waveforms and to foster closer collaboration between the numerical relativity and data analysis communities. We describe the results of the first NINJA analysis which focused on gravitational waveforms from binary black hole coalescence. Ten numerical relativity groups contributed numerical data which were used to generate a set of gravitational-wave signals. These signals were injected into a simulated data set, designed to mimic the response of the initial LIGO and Virgo gravitational-wave detectors. Nine groups analysed this data using search and parameter-estimation pipelines. Matched filter algorithms, un-modelled-burst searches and Bayesian parameter estimation and model-selection algorithms were applied to the data. We report the efficiency of these search methods in detecting the numerical waveforms and measuring their parameters. We describe preliminary comparisons between the different search methods and suggest improvements for future NINJA analyses. © 2009 IOP Publishing Ltd

Status of NINJA: The Numerical INJection Analysis project

The 2008 NRDA conference introduced the Numerical INJection Analysis project (NINJA), a new collaborative effort between the numerical relativity community and the data analysis community. NINJA focuses on modeling and searching for gravitational wave signatures from the coalescence of binary system of compact objects. We review the scope of this collaboration and the components of the first NINJA project, where numerical relativity groups, shared waveforms and data analysis teams applied various techniques to detect them when embedded in colored Gaussian noise. © 2009 IOP Publishing Ltd

Testing gravitational-wave searches with numerical relativity waveforms: Results from the first Numerical INJection Analysis (NINJA) project

The Numerical INJection Analysis (NINJA) project is a collaborative effort between members of the numerical relativity and gravitational-wave data analysis communities. The purpose of NINJA is to study the sensitivity of existing gravitational-wave search algorithms using numerically generated waveforms and to foster closer collaboration between the numerical relativity and data analysis communities. We describe the results of the first NINJA analysis which focused on gravitational waveforms from binary black hole coalescence. Ten numerical relativity groups contributed numerical data which were used to generate a set of gravitational-wave signals. These signals were injected into a simulated data set, designed to mimic the response of the Initial LIGO and Virgo gravitational-wave detectors. Nine groups analysed this data using search and parameter-estimation pipelines. Matched filter algorithms, un-modelled-burst searches and Bayesian parameter-estimation and model-selection algorithms were applied to the data. We report the efficiency of these search methods in detecting the numerical waveforms and measuring their parameters. We describe preliminary comparisons between the different search methods and suggest improvements for future NINJA analyses.Comment: 56 pages, 25 figures; various clarifications; accepted to CQ

Stroke genetics informs drug discovery and risk prediction across ancestries

Previous genome-wide association studies (GWASs) of stroke — the second leading cause of death worldwide — were conducted predominantly in populations of European ancestry1,2. Here, in cross-ancestry GWAS meta-analyses of 110,182 patients who have had a stroke (five ancestries, 33% non-European) and 1,503,898 control individuals, we identify association signals for stroke and its subtypes at 89 (61 new) independent loci: 60 in primary inverse-variance-weighted analyses and 29 in secondary meta-regression and multitrait analyses. On the basis of internal cross-ancestry validation and an independent follow-up in 89,084 additional cases of stroke (30% non-European) and 1,013,843 control individuals, 87% of the primary stroke risk loci and 60% of the secondary stroke risk loci were replicated (P < 0.05). Effect sizes were highly correlated across ancestries. Cross-ancestry fine-mapping, in silico mutagenesis analysis3, and transcriptome-wide and proteome-wide association analyses revealed putative causal genes (such as SH3PXD2A and FURIN) and variants (such as at GRK5 and NOS3). Using a three-pronged approach4, we provide genetic evidence for putative drug effects, highlighting F11, KLKB1, PROC, GP1BA, LAMC2 and VCAM1 as possible targets, with drugs already under investigation for stroke for F11 and PROC. A polygenic score integrating cross-ancestry and ancestry-specific stroke GWASs with vascular-risk factor GWASs (integrative polygenic scores) strongly predicted ischaemic stroke in populations of European, East Asian and African ancestry5. Stroke genetic risk scores were predictive of ischaemic stroke independent of clinical risk factors in 52,600 clinical-trial participants with cardiometabolic disease. Our results provide insights to inform biology, reveal potential drug targets and derive genetic risk prediction tools across ancestries

Ultralight vector dark matter search using data from the KAGRA O3GK run

Among the various candidates for dark matter (DM), ultralight vector DM can be probed by laser interferometric gravitational wave detectors through the measurement of oscillating length changes in the arm cavities. In this context, KAGRA has a unique feature due to differing compositions of its mirrors, enhancing the signal of vector DM in the length change in the auxiliary channels. Here we present the result of a search for U(1)B−L gauge boson DM using the KAGRA data from auxiliary length channels during the first joint observation run together with GEO600. By applying our search pipeline, which takes into account the stochastic nature of ultralight DM, upper bounds on the coupling strength between the U(1)B−L gauge boson and ordinary matter are obtained for a range of DM masses. While our constraints are less stringent than those derived from previous experiments, this study demonstrates the applicability of our method to the lower-mass vector DM search, which is made difficult in this measurement by the short observation time compared to the auto-correlation time scale of DM

Search for gravitational-lensing signatures in the full third observing run of the LIGO-Virgo network

Gravitational lensing by massive objects along the line of sight to the source causes distortions of gravitational wave-signals; such distortions may reveal information about fundamental physics, cosmology and astrophysics. In this work, we have extended the search for lensing signatures to all binary black hole events from the third observing run of the LIGO--Virgo network. We search for repeated signals from strong lensing by 1) performing targeted searches for subthreshold signals, 2) calculating the degree of overlap amongst the intrinsic parameters and sky location of pairs of signals, 3) comparing the similarities of the spectrograms amongst pairs of signals, and 4) performing dual-signal Bayesian analysis that takes into account selection effects and astrophysical knowledge. We also search for distortions to the gravitational waveform caused by 1) frequency-independent phase shifts in strongly lensed images, and 2) frequency-dependent modulation of the amplitude and phase due to point masses. None of these searches yields significant evidence for lensing. Finally, we use the non-detection of gravitational-wave lensing to constrain the lensing rate based on the latest merger-rate estimates and the fraction of dark matter composed of compact objects