767 research outputs found

    NEW VISIONS OF AFRICA: HOW AFRICAN STUDENTS AT HISTORICALLY BLACK COLLEGES AND UNIVERSITIES SHAPED BLACK EDUCATION, 1920-1960

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    This dissertation studies the relationship between African migrant students, Historically Black Colleges and Universities, and the Phelps-Stokes Fund. In the early twentieth century, the Phelps-Stokes Fund, a philanthropic organization founded on expanding educational accesses to Africans, African Americans, and Native Americans, launched two educational surveys through Africa. Its educational director, Thomas Jesse Jones, hoped that the tour would provide insight into African educational systems and expand his vision for Black education. The two surveys caught the attention of many Africans interested in expanding their education outside of Africa. As a result, future African state builders such as Nnamdi Azikiwe, Kwame Nkrumah, and several others came to know Thomas Jesse Jones and the Phelps-Stokes Fund. Jones used Phelps-Stokes Fund scholarships to help pay for African students’ college tuition in America, steering them toward schools that encouraged training in agriculture and other trades. Yet by funding students to study in the United States, Jones’ program had the unintended consequence of radicalizing Africans’ beliefs about education and decolonization. At Howard and Lincoln Universities, African students gained access to and studied under important African American educators, particularly William Hansberry and Alain Locke. The lessons students learned inside and outside the classroom helped shape their visions for a new Africa, free from colonial rule. African students also gained a new appreciation for the wider political struggle in which they were engaged. They joined and even formed Pan-African organizations both on and off their college campuses to promote unity and solidarity between people of African descent. They applied these lessons upon their return to the continent, working to undermine colonialism through the creation of new educational centers at the University of Ghana and Nigeria University. Born of a western model for perpetuating industrial education, Jones’ project thus ultimately led to the construction of institutions and identities that helped bring down colonial rule in Africa

    Evaluation of a ln tan integral arising in quantum field theory

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    We analytically evaluate a dilogarithmic integral that is prototypical of volumes of ideal tetrahedra in hyperbolic geometry. We additionally obtain new representations of the Clausen function Cl_2 and the Catalan constant G=Cl_2(\pi/2), as well as new relations between sine and Clausen function values.Comment: 24 pages, no figure

    Anthropogenic alluvium: An evidence-based meta-analysis for the UK Holocene

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    An exploratory meta-analysis of 14C-dated Holocene anthropogenic alluvium (AA) in the UK is presented. AA units were categorized by grain size, catchment area and location, depositional environment, and according to diagnostic criteria linked to recorded types of anthropogenic activity. The oldest AA units date to the Early Bronze Age (c. 4400 cal. BP) and there is an apparent 1500 year lag between the adoption of agriculture (c. 6000 cal. BP) in the UK and any impact on floodplain sedimentation. The earliest influence of farming on UK rivers appears to have been hydrological rather than sedimentological. The mediaeval period was characterized by accelerated sedimentation of fine-grained AA, notably in the smallest catchments. There are some apparent regional differences in the timing of AA formation with earlier prehistoric dates in central and southern parts of the UK

    Discovery and characterization of 91 novel transcripts expressed in cattle placenta

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    <p>Abstract</p> <p>Background</p> <p>Among the eutherian mammals, placental architecture varies to a greater extent than any other tissue. The diversity of placental types, even within a single mammalian order suggests that genes expressed in placenta are under strong Darwinian selection. Thus, the ruminant placenta may be a rich source of genes to explore adaptive evolutionary responses in mammals. The aim of our study was to identify novel transcripts expressed in ruminant placenta, and to characterize them with respect to their expression patterns, organization of coding sequences in the genome, and potential functions.</p> <p>Results</p> <p>A combination of bioinformatics, comparative genomics and transcript profiling was used to identify and characterize 91 novel transcripts (NTs) represented in a cattle placenta cDNA library. These NTs have no significant similarity to any non-ferungulate DNA or RNA sequence. Proteins longer than 100 aa were predicted for 29 NTs, and 21 are candidate non-coding RNAs. Eighty-six NTs were found to be expressed in one or more of 18 different tissues, with 39 (42%) showing tissue-preference, including six that were expressed exclusively in placentome. The authenticity of the NTs was confirmed by their alignment to cattle genome sequence, 42 of which showed evidence of mRNA splicing. Analysis of the genomic context where NT genes reside revealed 61 to be in intergenic regions, whereas 30 are within introns of known genes. The genes encoding the NTs were found to be significantly associated with subtelomeric regions.</p> <p>Conclusion</p> <p>The 91 lineage-specific transcripts are a useful resource for studying adaptive evolutionary responses of the ruminant placenta. The presence of so many genes encoding NTs in cattle but not primates or rodents suggests that gene loss and gain are important mechanisms of genome evolution in mammals. Furthermore, the clustering of NT genes within subtelomeric regions suggests that such regions are highly dynamic and may foster the birth of novel genes. The sequencing of additional vertebrate genomes with defined phylogenetic relationships will permit the search for lineage-specific genes to take on a more evolutionary context that is required to understand their origins and functions.</p

    Is Biventricular Vascular Coupling a Better Indicator of Ventriculo-Ventricular Interaction in Congenital Heart Disease?

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    BACKGROUND: Ventriculo-ventricular interactions are known to exist, though not well quantified. We hypothesised that the ventricular-vascular coupling ratio assessed by cardiovascular MRI would provide insight into this relationship. We also sought to compare MRI-derived ventricular-vascular coupling ratio to echocardiography and patient outcomes. METHODS: Children with cardiac disease and biventricular physiology were included. Sanz\u27s and Bullet methods were used to calculate ventricular-vascular coupling ratio by MRI and echocardiography, respectively. Subgroup analysis was performed for right and left heart diseases. Univariate and multivariate regressions were performed to determine associations with outcomes. RESULTS: A total of 55 patients (age 14.3 ± 2.5 years) were included. Biventricular ventricular-vascular coupling ratio by MRI correlated with each other (r = 0.41; p = 0.003), with respect to ventricle\u27s ejection fraction (r = -0.76 to -0.88; p \u3c 0.001) and other ventricle\u27s ejection fraction (r = -0.42 to -0.47; p \u3c 0.01). However, biventricular ejection fraction had only weak correlation with each other (r = 0.31; p = 0.02). Echo underestimated ventricular-vascular coupling ratio for the left ventricle (p \u3c 0.001) with modest correlation to MRI-derived ventricular-vascular coupling ratio (r = 0.43; p = 0.002). There seems to be a weak correlation between uncoupled right ventricular-vascular coupling ratio with the need for intervention and performance on exercise testing (r = 0.33; p = 0.02). CONCLUSION: MRI-derived biventricular ventricular-vascular coupling ratio provides a better estimate of ventriculo-ventricular interaction in children and adolescents with CHD. These associations are stronger than traditional parameters and applicable to right and left heart conditions

    Detailed Analysis of the Pulsations During and After Bursts from the Bursting Pulsar (GRO J1744-28)

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    The hard X-ray bursts observed during both major outbursts of the Bursting Pulsar (GRO J1744-28) show pulsations near the neutron star spin frequency with an enhanced amplitude relative to that of the persistent emission. Consistent with previous work, we find that the pulsations within bursts lag behind their expected arrival times based upon the persistent pulsar ephemeris. For an ensemble of 1293 bursts recorded with the Burst and Transient Source Experiment, the average burst pulse time delay is 61.0 +/- 0.8 ms in the 25 - 50 keV energy range and 72 +/- 5 ms in the 50 - 100 keV band. The residual time delay from 10 to 240 s following the start of the burst is 18.1 +/- 0.7 ms (25 - 50 keV). A significant correlation of the average burst time delay with burst peak flux is found. Our results are consistent with the model of the pulse time lags presented by Miller (1996).Comment: 11 pages, accepted for publication in Ap

    Using a mHealth system to recall and refer existing clients and refer community members with health concerns to primary healthcare facilities in South Africa: a feasibility study

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    Background: Lay health workers (LHWs) are critical in linking communities and primary healthcare (PHC) facilities. Effective communication between facilities and LHWs is key to this role. We implemented a mobile health (mHealth) system to improve communication and continuity of care for chronically ill clients. The system focused on requests from facility staff to LHWs to follow up clients and LHW referrals of people who needed care at a facility. We implemented the system in two rural and semi-rural sub-districts in South Africa. Objective: To assess the feasibility of the mHealth system in improving continuity of care for clients in PHC in South Africa. Method: We implemented the intervention in 15 PHC facilities. The clerks issued recalls to LHWs using a tablet computer. LHWs used smartphones to receive these requests, communicate with clerks and refer people to a facility. We undertook a mixed-methods evaluation to assess the feasibility of the mHealth system. We analysed recall and referral data using descriptive statistics. We used thematic content analysis to analyse qualitative data from semi-structured interviews with facility staff and a researcher fieldwork journal. Results: Across the sub-districts, 2,204 clients were recalled and 628 (28%) of these recalls were successful. LHWs made 1,085 referrals of which 485 (45%) were successful. The main client group referred and recalled were children under 5 years. Qualitative data showed the impacts of facility conditions and interpersonal relationships on the mHealth system. Conclusion: Using mHealth for recalls and referrals is probably feasible and can improve communication between LHWs and facility staff. However, the low success rates highlight the need to assess facility capacity beforehand and to integrate mHealth with existing health information systems. mHealth may improve communication between LHWs and facility staff, but its success depends on the health system capacity to incorporate these interventions
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