Interrelationships Among Changes in Leptin, Insulin, Cortisol and Growth Hormone and Weight Status in Youth

Objective: While acute alterations in leptin, insulin, cortisol and growth hormone (GH) levels have been reported in children following weight change interventions, little is known about natural hormonal changes as children grow and how these changes are affected b

The Relationship between Changes in Weight Status and Insulin Resistance in Youth

This study examined changes in insulin resistance (IR) in 120 youth over two years. IR was quantified via homeostatic model (HOMA-IR), and weight status changes were quantified via body mass index (BMI). When all participants were considered, the mean HOMA-IR and BMI increased 13.4% and 1.65 units, respectively. Change in BMI z-score and percent change in HOMA-IR were moderately associated (r = 0.39). Follow-up analyses were performed for the following weight groups: NN (normal at baseline and two years later), NO (normal to overweight), ON (overweight to normal), and OO (overweight at both points). The NO group had a greater change in HOMA-IR (+50%) compared to other groups: ON (−8%), NN (+2%), and OO (−0.1%) (P < .05). The association between changes in BMI z-score and HOMA-IR was r = 0.49 when only the NO and ON groups were included. These results reinforce the importance of preventing youth from becoming overweight to control IR

Subsidence and thermal history of an inverted Late Jurassic-Early Cretaceous extensional basin (Cameros, North-central Spain) affected by very low- to low-grade metamorphism.

The Cameros Basin (North Spain) is a Late Jurassic-Early Cretaceous extensional basin, which was inverted during the Cenozoic. It underwent a remarkable thermal evolution, as indicated by the record of anomalous high temperatures in its deposits. In this work the subsidence and thermal history of the basin is reconstructed, using subsidence analysis and 2D thermal modeling. Tectonic subsidence curves provide evidence of the occurrence of two rapid subsidence phases during the syn-extensional stage. In the first phase (Tithonian-Early Berriasian), the largest accommodation space was formed in the central sector of the basin, whereas in the second (Early Barremian-Early Albian), it was formed in the northern sector. These rapid subsidence phases could correspond to relevant tectonic events affecting the Iberian Plate at that time. By distinguishing between the initial and thermal subsidence and defining their relative magnitudes, Royden's (1986) method was used to estimate the heat flow at the end of the extensional stage. A maximum heat flow of 60-65 mW/m2 is estimated, implying only a minor thermal disturbance associated with extension. In contrast with these data, very high vitrinite reflectance, anomalously distributed in some case with respect to the typical depth-vitrinite reflectance relation, was measured in the central-northern sector of the basin. Burial and thermal data are used to construct a 2D thermal basin model, to elucidate the role of the processes involved in sediment heating. Calibration of the thermal model with the vitrinite reflectance (%Ro) and fluid inclusion (FI) data indicates that in the central and northern sectors of the basin, an extra heat source, other than a typical rift, is required to explain the observed thermal anomalies. The distribution of the %Ro and FI values in these sectors suggests that the high temperatures and their distribution are related to the circulation of hot fluids. Hot fluids were attributed to the hydrothermal metamorphic events affecting the area during the early post-extensional and inversion stages of the basin

Yearling bulls have reduced sperm concentration and increased seminal plasma interleukin-8 after a 28-day breeding season

We hypothesized that yearling bulls selected for a 28-d breeding season would have reduced sperm concentrations and morphology, and have increased seminal plasma concentrations of pro-inflammatory cytokine interleukin-8 (IL-8). Yearling bulls were selected based on a breeding soundness examination (BSE) at approximately 415 d of age and contained at least 750 million sperm in the ejaculate, with 12 bulls randomly selected for breeding (BREEDERS) and 12 bulls not selected for breeding (NON-BREEDERS). After a 28-d breeding period, all bulls underwent a BSE. Plasma and seminal plasma were collected at each time point for analysis. Data were analysed utilizing either the MIXED or GLIMMIX procedures with repeated measures in SAS with breeding group, age and the interaction as fixed effects. Sperm concentration per ml of ejaculate was reduced (p \u3c .05) in yearling bulls used for breeding compared with those not used for breeding at the end of the breeding season. Seminal plasma IL-8 concentrations in yearling bulls used for breeding were increased (p \u3c .05) after the breeding season compared with bulls not used for breeding. Taken together, yearling bulls selected for a 28-d breeding season have reduced sperm production per ml of an ejaculate and increased inflammatory response in the seminal plasma that can lead to impaired breeding response if they are to be used for more than 30 d of breeding

Untersuchungen zur mathematischen Simulation der Sandsteindiagenese und der damit verbundenen Veränderungen der Porosität und Permeabilität

Porosity is an important reservoir property which determines storage capacity and transport coefficients of rocks. Therefore, much attention is paid to diagenetic processes affecting this specific rock property. Two processes dominate the evolution of porosity in clastic rocks: a) mechanical diagenesis, with porosity reduction by compaction due to increasing overburden and b) chemical diagenesis, which modifies porosity by dissolution and precipitation of minerals. For the quantification of the diagenetic evolution of elastic rocks it is necessary to study the different mechanisms separately in order to be able to assign the respective changes to the different processes. While there are several models to quantify compaction there exist only few simple models for the quantification of the diagenetic changes due to mineraldissolution and precipitation. Therefore, the paper concentrates entirely on chemo-physical and mathematical models describing chemical diagenesis. The first step in the development of the model concerns the temporal evolution of dissolved chemical species in the pore fluid due to transport and to chemical reactions. The addition of a reaction term to the transport term allows to take into account the redistribution of dissolved species in the pore fluid due to fluid mixing and temperature changes. Furthermore, the reaction term represents a source/sink term describing the water-rock interaction. These chemical changes then are transposed into the temporal development of the mineral composition and their influences on porosity evolution. The final model allows to quantify changes in porosity and mineral composition, and to determine the temporal concentration modifications of all species dissolved in the pore fluid . Whereby, changes within the pore fluid composition due to mineral reactions are modeled under consideration of transport and mixing. The distinction between transport induced pore fluid evolution, and its interaction with the solids allows to maintain an exact mass balance of the system even if a mineral species is no more available for the reactions. The calculation of mineral dissolution requires the solution of a coupled, nonlinear system of equations. In order to solve such a system under a variety of initial and boundary conditionsan extremely stable algorithm has been developed and has been applied to a calcic model sandstone. Finally, some basic models are discussed with regard to the porosity development in space and time regarding pure and calcite cemented Quartzsandstones in a flow dominated regime. A gently dipping, confined sandstone layer is bounded by two faults. The geothermal gradient is constant throughout the basin and in time. Temperature increases with depth along the dip ofthe layer. Thus, the temperature gradient along the layer will vary depending on its slope. The thickness of the layer is small with respect to its lateral extension. Pore fluid with a predetermined composition enters the layer from one side and moves through the layer dissolving or precipitating quartz or calcite depending on the temperature conditions and the composition of the fluid. The idealized calculations indicate that pore water flow can be an important factor determining much of the diagenetic evolution of sandstones. While redistribution of quartz depends mainly on the temperature gradient along the flow path, redistribution of calcite in addition is controlled by the chemical composition of the pore fluid and it is especially sensitive to any source of CO$_{2}$. Therefore, in geologic applications not only the temporal development of the basin geometry and the temperature history must be considered, but also any CO$_{2}$ source must be taken into account as a very important factor controlling the diagenetic evolution of sandstones. Another important point is the inhomogeneous distribution of the initial porosity which determines the fluxes and, in consequence, the modification of porosity and permeability

The present-day temperature field of the Northeast German Basin - A comparison of temperature measurements and 3D-modeling

Ondrak Robert, Foerster Andrea, Scheck Magdalena, Gerisch Ronald. The present-day temperature field of the Northeast German Basin - A comparison of temperature measurements and 3D-modeling. In: Transferts dans les systèmes sédimentaires : de l'échelle du pore à celle du bassin. Réunion spécialisée SGF-TRABAS/CNRS, Paris 27-28 septembre 1999. Résumés. Strasbourg : Institut de Géologie – Université Louis-Pasteur, 1999. pp. 111-114. (Sciences Géologiques. Mémoire, 99

The present-day temperature field of the Northeast German Basin - A comparison of temperature measurements and 3D-modeling

Ondrak Robert, Foerster Andrea, Scheck Magdalena, Gerisch Ronald. The present-day temperature field of the Northeast German Basin - A comparison of temperature measurements and 3D-modeling. In: Transferts dans les systèmes sédimentaires : de l'échelle du pore à celle du bassin. Réunion spécialisée SGF-TRABAS/CNRS, Paris 27-28 septembre 1999. Résumés. Strasbourg : Institut de Géologie – Université Louis-Pasteur, 1999. pp. 111-114. (Sciences Géologiques. Mémoire, 99