Search results for "PRESSURE"

Shifts in size, genetic structure and activity of the soil denitrifier community by nematode grazing

2010

International audience; Bacterial-feeding nematodes represent an important driver of the soil microbial activity and diversity. This study aimed at characterizing the impact of nematode grazing on a model functional bacterial guild involved in N-cycling, the denitrifiers. Bacterial-feeding nematodes (Cephalobus pseudoparvus) were inoculated into soil microcosms whose indigenous nematofauna had previously been removed. The size, genetic structure and activity of the soil denitrifier community were characterized 15 and 45 days after nematodes inoculation using quantitative PCR of the nirK, nirS and nosZ denitrification genes, fingerprinting of the nirK and nirS genes and denitrification enzym…

Bader’s topological analysis of the electron density in the pressure-induced phase transitions/amorphization in α-quartz from the catastrophe theory …

2013

In this work, the Bader's topological analysis of the electron density, coupled with Thom's catastrophe theory, was used to characterize the pressure-induced transformations in α-quartz. In particular, ab initio calculations of the α-quartz structures in the range 0-105 Gpa have been performed at the HF/DFT exchange-correlation terms level, using Hamiltonians based on a WC1LYP hybrid scheme. The electron densities calculated throughout the ab initio wave functions have been analysed by means of the Bader's theory, seeking for some catastrophic mechanism in the sense of Thom's theory. The analysis mainly showed that there is a typical fold catastrophe feature involving an O-O interaction at …

Comparison of posturographic parameters between young taekwondo and tennis athletes

2018

[Purpose] Physical activity can influence the development of postural control and balance. Therefore, the aim of study was to use posturography assessment to compare balance control on the Romberg test between athletes in two very different sports, taekwondo and tennis. [Participants and Methods] Twenty-nine young athletes participated in the study, 11 forming the taekwondo group and 18 the tennis group. Posturography was performed using the FreeMed system (Sensor Medica). Between-group differences were evaluated using unpaired Student’s t-test. [Results] There was a significance between-group difference in the centre of pressure and the ellipse surface area with no between-group difference…

Improvement of balance in a 7-year-old child through a six-week learning programme

2018

Given that human beings are constantly subjected to equilibration processes, developing basic perceptual motor skills, especially balance, is important. The main purpose of this study is the validation of the tasks and the progression of activities that form the learning programme for balance development in a six-week didactic unit of 12 sessions (2 sessions per week), for 6 to 9 year old children (1st, 2nd, and 3rd grade of elementary school in Brazil). The changes in balance after applying the programme are also analysed through a new measuring protocol using baropodometry. Although the session was put into practice in a class of 28 children, data were extracted from a 7-year-old child. T…

First gas and thermal measurements at the frequently erupting Gamalama volcano (Indonesia) reveal a hydrothermally dominated magmatic system

2020

Abstract The first gas and thermal measurements at the summit of the Gamalama volcano indicate that the system is dominated by hydrothermal processes. This is highlighted by the prevalence of H2S over SO2 (H2S/SO2 = 2–8), a high CO2/SO2 ratio (76–201), and a low heat transfer (3.0 MW) to the surface. A relative variation in gas composition is observed along the degassing fracture zone, possibly due to partial S scrubbing. Despite this surface hydrothermal signature, the system exhibits high gas equilibrium temperatures (425–480 °C), indicating that fluids are not exclusively derived from a boiling hydrothermal aquifer, but also sourced by cooling and crystallizing basaltic magma at deep tha…

Investigation of the He solubility in H2O-CO2 bearing silicate liquids at moderate pressure: a new experimental method

2000

We have designed the first available experimental method capable to investigate the solubility of inert gases in H2O–CO2 bearing silicate melts in a large range of pressures. The method overcomes the difficulties imposed by the physical state of volatiles at room conditions. Experiments were done by using an internally heated pressure vessel, where sealed capsules containing the sample are introduced. The peculiarity of the method consists in the capability of loading, in accurately known proportions (even lower than ppm), volatiles in a gaseous state at room conditions. Gas is loaded as a weighed amount of a gas-bearing glass, which was previously prepared by using the same gas as a pressu…

Isolated Systolic Hypertension in the Young

2019

Elevated systolic blood pressure with normal diastolic blood pressure is the most prevalent type of hypertension in young people. The prevalence of isolated systolic hypertension reported among youth ranges widely as a result of the differences in population characteristics such as age, ethnicity, and obesity. Even though it is not an unusual condition, there is still debate in the literature about the clinical significance of an isolated increase in systolic blood pressure detected in the first decades of life. The reported phenotypic characteristics of subjects with isolated systolic hypertension are rather scarce and many relevant pieces of information are still elusive. Further studies …

PENTAZOCINE HAMPERS BILE FLOW

1985

Efficient prediction of thermodynamic properties of quadrupolar fluids from simulation of a coarse-grained model: the case of carbon dioxide.

2008

Monte Carlo simulations are presented for a coarse-grained model of real quadrupolar fluids. Molecules are represented by particles interacting with Lennard-Jones forces plus the thermally averaged quadrupole-quadrupole interaction. The properties discussed include the vapor-liquid coexistence curve, the vapor pressure along coexistence, and the surface tension. The full isotherms are also accessible over a wide range of temperatures and densities. It is shown that the critical parameters (critical temperature, density, and pressure) depend almost linearly on a quadrupolar parameter q=Q(*4)T*, where Q* is the reduced quadrupole moment of the molecule and T* the reduced temperature. The mode…

HR3DHG version 1: modeling the spatiotemporal dynamics of mercury in the Augusta Bay (southern Italy)

2020

The biogeochemical dynamics of Hg, and specifically of its three species Hg0, HgII, and MeHg (elemental, inorganic, and organic, respectively), in the marine coastal area of Augusta Bay (southern Italy) have been explored by the high-resolution 3D Hg (HR3DHG) model, namely an advection–diffusion–reaction model for dissolved mercury in the seawater compartment coupled with a diffusion–reaction model for dissolved mercury in the pore water of sediments in which the desorption process for the sediment total mercury is taken into account. The spatiotemporal variability of the mercury concentration in both seawater ([HgD]) and the first layers of bottom sediments ([HgDsed] and [HgTsed]), as well…