Observational diagnostics of gas in protoplanetary disks

Protoplanetary disks are composed primarily of gas (99% of the mass). Nevertheless, relatively few observational constraints exist for the gas in disks. In this review, I discuss several observational diagnostics in the UV, optical, near-IR, mid-IR, and (sub)-mm wavelengths that have been employed to study the gas in the disks of young stellar objects. I concentrate in diagnostics that probe the inner 20 AU of the disk, the region where planets are expected to form. I discuss the potential and limitations of each gas tracer and present prospects for future research.Comment: Review written for the proceedings of the conference "Origin and Evolution of Planets 2008", Ascona, Switzerland, June 29 - July 4, 2008. Date manuscript: October 2008. 17 Pages, 6 graphics, 134 reference

Detection of interstellar oxidaniumyl: Abundant H2O+ towards the star-forming regions DR21, Sgr B2, and NGC6334

Aims. We identify a prominent absorption feature at 1115 GHz, detected in first HIFI spectra towards high-mass star-forming regions, and interpret its astrophysical origin. Methods. The characteristic hyperfine pattern of the H2O+ ground-state rotational transition, and the lack of other known low-energy transitions in this frequency range, identifies the feature as H2O+ absorption against the dust continuum background and allows us to derive the velocity profile of the absorbing gas. By comparing this velocity profile with velocity profiles of other tracers in the DR21 star-forming region, we constrain the frequency of the transition and the conditions for its formation. Results. In DR21, the velocity distribution of H2O+ matches that of the [Cii] line at 158 μm and of OH cm-wave absorption, both stemming from the hot and dense clump surfaces facing the Hii-region and dynamically affected by the blister outflow. Diffuse foreground gas dominates the absorption towards Sgr B2. The integrated intensity of the absorption line allows us to derive lower limits to the H2O+ column density of 7.2 × 1012 cm−2 in NGC 6334, 2.3 × 1013 cm−2 in DR21, and 1.1 × 1015 cm−2 in Sgr B2

An integrative cross-omics analysis of DNA methylation sites of glucose and insulin homeostasis

Despite existing reports on differential DNA methylation in type 2 diabetes (T2D) and obesity, our understanding of its functional relevance remains limited. Here we show the effect of differential methylation in the early phases of T2D pathology by a blood-based epigenome-wide association study of 4808 non-diabetic Europeans in the discovery phase and 11,750 individuals in the replication. We identify CpGs in LETM1, RBM20, IRS2, MAN2A2 and the 1q25.3 region associated with fasting insulin, and in FCRL6, SLAMF1, APOBEC3H and the 15q26.1 region with fasting glucose. In silico cross-omics analyses highlight the role of differential methylation in the crosstalk between the adaptive immune system and glucose homeostasis. The differential methylation explains at least 16.9% of the association between obesity and insulin. Our study sheds light on the biological interactions between genetic variants driving differential methylation and gene expression in the early pathogenesis of T2D

Simulation of rumen particle dynamics using a non-steady state model of rumen digestion and nutrient availability in dairy cows fed sugarcane

An extant dynamic model of digestion and absorption of nutrients in cattle fed sugarcane was adapted for non-steady state feeding conditions. This modified model includes mechanisms of particle size reduction and delay in availability of particles and intracellular contents for microbial fermentation after ingestion. Two trials (one with beef cattle and the other with dairy cattle) were used to evaluate the non-steady state model. In general, predicted values were close to observed values for duodenal neutral detergent fibre (NDF) and nitrogen flows (mean squared prediction error (MSPE) of 14% and 15% of observed mean, respectively). There was no indication of over- or underprediction of NDF and nitrogen flows. An overestimation of rumen volume observed in steers suggests that the equation to calculate rumen volume needs to be adapted for low feed intake. Overall mean of milk production was predicted accurately. Predictions under non-steady state conditions showed higher accuracy when real intake behaviour was simulated. The model can be used to select strategies of supplementation of dairy cows fed sugarcane-based diets

Transport des sediments au-dessus des ondulations dans les vagues et courants

SIGLEAvailable at INIST (FR), Document Supply Service, under shelf-number : 26165 C, issue : a.1996 n.44 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc

Inventory control for joint manufacturing and remanufacturing

SIGLEAvailable from INIST (FR), Document Supply Service, under shelf-number : DO 6031 / INIST-CNRS - Institut de l'Information Scientifique et TechniqueFRFranc