THE PRESIDENT AND INFORMATION MANAGEMENT: AN EXPERIMENT IN THE CARTER WHITE HOUSE

Information Systems Working Papers Serie

Continuous loss of oocytes throughout meiotic prophase in the normal mouse ovary

AbstractThe number of germ cells reaches the maximum just prior to entry into meiosis, yet decreases dramatically by a few days after birth in the female mouse, rat, and human. Previous studies have reported a major loss at the pachytene stage of meiotic prophase during fetal development, leading to the hypothesis that chromosomal pairing abnormalities may be a signal for oocyte death. However, the identification as well as the quantification of germ cells in these studies have been questioned. A recent study using Mouse Vasa Homologue (MVH) as a germ cell marker reached a contradictory conclusion claiming that oocyte loss occurs in the mouse only after birth. In the present study, we established a new method to quantify murine germ cells by using Germ Cell Nuclear Antigen-1 (GCNA-1) as a germ cell marker. Comparison of GCNA-1 and MVH immunolabeling revealed that the two markers identify the same population of germ cells. However, nuclear labeling of GCNA-1 was better suited for counting germ cells in histological sections as well as for double labeling with the antibody against synaptonemal complex (SC) proteins in chromosome spreading preparations. The latter experiment demonstrated that the majority of GCNA-1-labeled cells entered and progressed through meiotic prophase during fetal development. The number of GCNA-1-positive cells in the ovary was estimated by counting the labeled cells retained in chromosome spreading preparations and also in histological sections by using the ratio estimation method. Both methods demonstrated a continuous decline in the number of GCNA-1-labeled cells during fetal development when the oocytes progress through meiotic prophase. These observations suggest that multiple causes are responsible for oocyte elimination

Complete abolition of reading and writing ability with a third ventricle colloid cyst: implications for surgical intervention and proposed neural substrates of visual recognition and visual imaging ability.

We report a rare case of a patient unable to read (alexic) and write (agraphic) after a mild head injury. He had preserved speech and comprehension, could spell aloud, identify words spelt aloud and copy letter features. He was unable to visualise letters but showed no problems with digits. Neuropsychological testing revealed general visual memory, processing speed and imaging deficits. Imaging data revealed an 8 mm colloid cyst of the third ventricle that splayed the fornix. Little is known about functions mediated by fornical connectivity, but this region is thought to contribute to memory recall. Other regions thought to mediate letter recognition and letter imagery, visual word form area and visual pathways were intact. We remediated reading and writing by multimodal letter retraining. The study raises issues about the neural substrates of reading, role of fornical tracts to selective memory in the absence of other pathology, and effective remediation strategies for selective functional deficits

THE PRESIDENT AND INFORMATION MANAGEMENT: AN EXPERIMENT IN THE CARTER WHITE HOUSE

Information Systems Working Papers Serie

Evaluación de los modelos de aprendizajes educativos aplicados en los niveles de inglés en la Bluefields Indian & Caribbean University (BICU)

El objetivo general de esta investigación fue evaluar los modelos de aprendizaje aplicados en los niveles de inglés de la Bluefields Indian & Caribbean University (BICU). La investigación se llevó a cabo utilizando un enfoque cualitativo. Se trabajó en las sedes principales de BICU en Bluefields y Bilwi. Los participantes del estudio fueron estudiantes, docentes y directivos del departamento de inglés. Se utilizó un muestreo no probabilístico por conveniencia para la selección de los participantes. Las técnicas de recolección de datos incluyeron: entrevistas a docentes y directivos, encuestas a estudiantes y observaciones de clases. Para el procesamiento y análisis de la información, se utilizó la herramienta de formularios de Google y Microsoft Excel. Se aplicó una prueba piloto para validar la credibilidad y confiabilidad de los instrumentos. Los resultados más importantes de la investigación incluyen, Caracterización sociocultural de los estudiantes: Se obtuvo información sobre la edad, sexo, etnia, lengua materna y nivel de inglés de los estudiantes participantes. Se identificaron las metodologías utilizadas por los docentes, como el método comunicativo, directo, gramática-traducción, audiolingual y Total Physical Response (TPR). Los estudiantes evaluaron positivamente las metodologías empleadas por los docentes, destacando la claridad en la presentación de los temas y la comunicación de los objetivos de clase. Sin embargo, se identificaron algunas debilidades, como la falta de actividades motivadoras y la limitada integración de las cuatro habilidades lingüísticas (escuchar, hablar, leer y escribir). Como Propuestas de estrategias metodológicas, a partir de los hallazgos, se plantean recomendaciones para mejorar el proceso de aprendizaje del inglés, como la implementación de metodologías más participativas y el uso de recursos tecnológicos. También se sugiere la capacitación y desarrollo profesional continuo de los docentes, así como la colaboración con otras instituciones y expertos en la enseñanza del inglés como segunda lengua. En resumen, esta investigación proporciona un análisis detallado de los modelos de aprendizaje aplicados en los niveles de inglés de BICU, con el fin de contribuir al fortalecimiento del proceso de aprendizaje del idioma inglés en la universidad

Primary differentiation in the human blastocyst : comparative molecular portraits of inner cell mass and trophectoderm cells

The primary differentiation event during mammalian development occurs at the blastocyst stage and leads to the delineation of the inner cell mass (ICM) and the trophectoderm (TE). We provide the first global mRNA expression data from immunosurgically dissected ICM cells, TE cells, and intact human blastocysts. Using a cDNA microarray composed of 15,529 cDNAs from known and novel genes, we identify marker transcripts specific to the ICM (e.g., OCT4/POU5F1, NANOG, HMGB1, and DPPA5) and TE (e.g., CDX2, ATP1B3, SFN, and IPL), in addition to novel ICM- and TE-specific expressed sequence tags. The expression patterns suggest that the emergence of pluripotent ICM and TE cell lineages from the morula is controlled by metabolic and signaling pathways, which include inter alia, WNT, mitogen-activated protein kinase, transforming growth factor-beta, NOTCH, integrin-mediated cell adhesion, phosphatidylinositol 3-kinase, and apoptosis. These data enhance our understanding of the first step in human cellular differentiation and, hence, the derivation of both embryonic stem cells and trophoblastic stem cells from these lineages

Motherhood on ice? A media framing analysis of older mothers in the UK news

Changing gender roles and increased sexual and economic freedom have created opportunities for women to give birth relatively late in life. However, stigma and misplaced fears about physical capacity are often reported as sources of anxiety among older, and in vitro fertilisation-induced mothers. In this study, we apply a specially adapted method for analysing news media content to a week's selection of material in the British media following the dissemination of research at an international medical conference. Our findings suggest, despite some positive commentaries, that much negative discourse is circulated by the media about older mothers, from implied claims of selfishness (older mothers as 'delaying' conception) to violations of the 'natural order'. These latter claims reflect the long-standing ambivalence by the media generally towards scientific advancement, but they also reveal continuing resistance towards unorthodox lifestyles

Sex chromosome positions in human interphase nuclei as studied by in situ hybridization with chromosome specific DNA probes

Two cloned repetitive DNA probes, pXBR and CY1, which bind preferentially to specific regions of the human X and Y chromosome, respectively, were used to study the distribution of the sex chromosomes in human lymphocyte nuclei by in situ hybridization experiments. Our data indicate a large variability of the distances between the sex chromosomes in male and female interphase nuclei. However, the mean distance observed between the X and Y chromosome was significantly smaller than the mean distance observed between the two X-chromosomes. The distribution of distances determined experimentally is compared with three model distributions of distances, and the question of a non-random distribution of sex chromosomes is discussed. Mathematical details of these model distributions are provided in an Appendix to this paper. In the case of a human translocation chromosome (XqterXp22.2::Yq11Y qter) contained in the Chinese hamster x human hybrid cell line 445 x 393, the binding sites of pXBR and CY1 were found close to each other in most interphase nuclei. These data demonstrate the potential use of chromosome-specific repetitive DNA probes to study the problem of interphase chromosome topography