Quantitative analysis of postnatal neurogenesis and neuron number in the macaque monkey dentate gyrus

The dentate gyrus is one of only two regions of the mammalian brain where substantial neurogenesis occurs postnatally. However, detailed quantitative information about the postnatal structural maturation of the primate dentate gyrus is meager. We performed design-based, stereological studies of neuron number and size, and volume of the dentate gyrus layers in rhesus macaque monkeys (Macaca mulatta) of different postnatal ages. We found that about 40% of the total number of granule cells observed in mature 5-10-year-old macaque monkeys are added to the granule cell layer postnatally; 25% of these neurons are added within the first three postnatal months. Accordingly, cell proliferation and neurogenesis within the dentate gyrus peak within the first 3 months after birth and remain at an intermediate level between 3 months and at least 1 year of age. Although granule cell bodies undergo their largest increase in size during the first year of life, cell size and the volume of the three layers of the dentate gyrus (i.e. the molecular, granule cell and polymorphic layers) continue to increase beyond 1 year of age. Moreover, the different layers of the dentate gyrus exhibit distinct volumetric changes during postnatal development. Finally, we observe significant levels of cell proliferation, neurogenesis and cell death in the context of an overall stable number of granule cells in mature 5-10-year-old monkeys. These data identify an extended developmental period during which neurogenesis might be modulated to significantly impact the structure and function of the dentate gyrus in adulthood.

Small-area estimation with spatial similarity

A class of composite estimators of small area quantities that exploit spatial (distancerelated)similarity is derived. It is based on a distribution-free model for the areas, but theestimators are aimed to have optimal design-based properties. Composition is applied alsoto estimate some of the global parameters on which the small area estimators depend.It is shown that the commonly adopted assumption of random effects is not necessaryfor exploiting the similarity of the districts (borrowing strength across the districts). Themethods are applied in the estimation of the mean household sizes and the proportions ofsingle-member households in the counties (comarcas) of Catalonia. The simplest version ofthe estimators is more efficient than the established alternatives, even though the extentof spatial similarity is quite modest.

Koulusaavutusaineiston analyysi asetelmaperusteisilla ja kaksitasoisilla logit-regressiomalleilla

Summary: The analysis of educational data with design-based and two-level logistic regression models

Organic acid adsorption and mineralization in oxisols with different textures

Organic acids play an important role in the nutritional conditions of plants. Their relevance is related to their formation dynamics, mineralization rate and adsorption by soil colloids. This study was carried out to evaluate the dynamics of mineralization and adsorption of organic acid (acetic acid - AA, citric acid - CA and humic acid - HA) applied to the soil. Samples of two Oxisols were used: Rhodic Haplustox (LV) and Typic Haplustox (LVA). The mineralization experiment was arranged in a 2 x 3 x 5 factorial design, based on the factors: two soils (LV and LVA) x three organic acid (OA) types (AA, CA and HA) x five OA rates (0, 1, 2, 4, and 8 mmol dm-3). Organic carbon mineralization in samples was measured by the C-CO2 efflux, produced by the microbial activity, in a 30-day (measurements after 4, 8, 12, 21, and 30 days) and in a 4-day experiment (measured after 24, 48, 72 and 96 h). Organic acid adsorption was tested in a 2 x 2 x 5 x 4 factorial design, with the factors and levels: two Oxisols; two organic acids (AA and CA); five OA rates (0, 1, 2, 4, and 8 mmol dm-3) and four adsorption periods (6, 24, 48, and 72 h). The C-CO2 production of soil treated with CA was highest. In the adsorption experiment, the affinity of CA to soil adsorption sites was greatest. The adsorption of organic acids to soils may be an important mechanism by which bioavailability and thus mineralization capacity by microbial activity are reduced.

IRENE newsletter. Volume 1, number 1 (Spring/Summer 2007)

IRENE’s mission is to improve the health and well-being of Iowans through collaboration in practice-based research on questions important to primary care physicians and their patients. IRENE’s purpose is to create and foster a network of research collaboration between the academic medical center and primary care physicians through out the state of Iowa with a particular focus on improving rural health.

IRENE newsletter. Volume 1, number 2 (Fall/Winter 2007). University of Iowa

IRENE’s mission is to improve the health and well-being of Iowans through collaboration in practice-based research on questions important to primary care physicians and their patients. IRENE’s purpose is to create and foster a network of research collaboration between the academic medical center and primary care physicians through out the state of Iowa with a particular focus on improving rural health.

IRENE newsletter. Volume 2, number 1 (Spring/Summer 2008). University of Iowa

IRENE’s mission is to improve the health and well-being of Iowans through collaboration in practice-based research on questions important to primary care physicians and their patients. IRENE’s purpose is to create and foster a network of research collaboration between the academic medical center and primary care physicians through out the state of Iowa with a particular focus on improving rural health.

IRENE newsletter. Volume 4, number 1 (Spring/Summer 2010)

IRENE’s mission is to improve the health and well-being of Iowans through collaboration in practice-based research on questions important to primary care physicians and their patients. IRENE’s purpose is to create and foster a network of research collaboration between the academic medical center and primary care physicians through out the state of Iowa with a particular focus on improving rural health.

IRENE newsletter. Volume 4, number 2 (Fall/Winter 2010)

IRENE’s mission is to improve the health and well-being of Iowans through collaboration in practice-based research on questions important to primary care physicians and their patients. IRENE’s purpose is to create and foster a network of research collaboration between the academic medical center and primary care physicians through out the state of Iowa with a particular focus on improving rural health.

IRENE newsletter. Volume 1, number 2 (Fall/Winter 2007)

IRENE’s mission is to improve the health and well-being of Iowans through collaboration in practice-based research on questions important to primary care physicians and their patients. IRENE’s purpose is to create and foster a network of research collaboration between the academic medical center and primary care physicians through out the state of Iowa with a particular focus on improving rural health.

IRENE newsletter. Volume 2, number 1 (Spring/Summer 2008)

IRENE’s mission is to improve the health and well-being of Iowans through collaboration in practice-based research on questions important to primary care physicians and their patients. IRENE’s purpose is to create and foster a network of research collaboration between the academic medical center and primary care physicians through out the state of Iowa with a particular focus on improving rural health.

IRENE newsletter. Volume 2, number 2 (Fall/Winter 2008)

IRENE’s mission is to improve the health and well-being of Iowans through collaboration in practice-based research on questions important to primary care physicians and their patients. IRENE’s purpose is to create and foster a network of research collaboration between the academic medical center and primary care physicians through out the state of Iowa with a particular focus on improving rural health.

IRENE newsletter. Volume 3, number 1 (Spring/Summer 2009)

IRENE’s mission is to improve the health and well-being of Iowans through collaboration in practice-based research on questions important to primary care physicians and their patients. IRENE’s purpose is to create and foster a network of research collaboration between the academic medical center and primary care physicians through out the state of Iowa with a particular focus on improving rural health.

IRENE newsletter. Volume 3, number 2 (Fall/Winter 2009)

IRENE’s mission is to improve the health and well-being of Iowans through collaboration in practice-based research on questions important to primary care physicians and their patients. IRENE’s purpose is to create and foster a network of research collaboration between the academic medical center and primary care physicians through out the state of Iowa with a particular focus on improving rural health.

IRENE newsletter. Volume 5, number 1 (Spring/Summer 2010)

IRENE’s mission is to improve the health and well-being of Iowans through collaboration in practice-based research on questions important to primary care physicians and their patients. IRENE’s purpose is to create and foster a network of research collaboration between the academic medical center and primary care physicians through out the state of Iowa with a particular focus on improving rural health.