The Lyman-alpha forest and WMAP year three

A combined analysis of Cosmic Microwave Background (CMB) and Lyman-a forest data allows to constrain the matter power spectrum from small scales of about 1 Mpc/h all the way to the horizon scale. The long lever arm and complementarity provided by such an analysis has previously led to a significant tightening of the constraints on the shape and the amplitude of the power spectrum of primordial density fluctuations. We present here a combined analysis of the WMAP three year results with Lyman-a forest data. The amplitude of the matter power spectrum sigma_8 and the spectral index ns inferred from the joint analysis with high resolution Lyman-a forest data and low resolution Lyman-a forest data as analyzed by Viel & Haehnelt (2006) are consistent with the new WMAP results to within 1 sigma. The joint analysis with the mainly low resolution data as analysed by McDonald et al. (2005) suggests a value of sigma_8 which is ~ 2 sigma higher than that inferred from the WMAP three year data alone. The joint analysis of the three year WMAP and the Lyman-a forest data also does not favour a running of the spectral index. The best fit values for a combined analysis of the three year WMAP data, other CMB data, 2dF and the Lyman-a forest data are (sigma_8, ns) = (0.78\pm 0.03,0.96 \pm 0.01).Comment: 5 pages, 4 figs, 2 tables. MNRAS letters in pres

Exploratory Graphics of a Financial Dataset

company rating, default probability, support vector machines, colour coding

Evaluation of MRN complex and ATM protein-protein interactions using cleavable DSSO crosslinking and mass spectrometry

Ataxia telangiectasia (A–T) is an inherited autosomal recessive disorder caused by mutations in the ataxia telangiectasia mutated (ATM) gene. The canonical role of ATM is to induce cell checkpoint arrest following DNA damage. When cells experience DNA double-strand breaks (DSBs), the Mre11-Rad50-Nbs1 (MRN) complex senses the damage, activating ATM, which mobilizes a protective signaling cascade, activating the cell cycle checkpoint, arresting cell growth. If the extent of damage is excessive, the apoptotic pathway is activated; otherwise DNA repair is initiated using either homologous recombination (HR) or through non-homologous end joining (NHEJ). ATM also plays a key role in redox homeostasis. Loss of this cellular function results in the misfolding and aggregation of proteins. Misfolded proteins are degraded by three pathways: the ubiquitin proteasome system (UPS), macroautophagy and chaperone-mediated autophagy (CMA). Aggregated proteins that are resistant to these protein clearance mechanisms can form inclusion bodies, which can lead to neurodegeneration. The primary approach used for investigating protein interactions in this research was with the DSSO cleavable crosslinking technique: first to evaluate the MRN protein complex structure and protein-protein interactions; then to elucidate ATM binding partners in cells undergoing oxidative stress. The results of the MRN complex in vitro crosslinking experiment were that 53 unique crosslinks were detected. These were subsequently evaluated by calculating molecular distances between identified crosslinked residues using known crystal structures of homologous proteins. Conversely, the results of the ATM in vivo crosslinking experiment were that, while informative crosslinks were not detected between ATM and other proteins, certain pathways were over-, and under-represented in the Co-IP of cells expressing the ATM constructs. Specifically, the parkin-ubiquitin proteasomal system pathway was over-represented, while the proteasome degradation pathway was under-represented. Additionally, the small heat shock protein 27 (Hsp27) was found to be enriched, a chaperone known for its protective role in protein aggregation diseases.Cellular and Molecular Biolog

Statistical characterization of polychromatic absolute and differential squared visibilities obtained from AMBER/VLTI instrument

In optical interferometry, the visibility squared modulus are generally assumed to follow a Gaussian distribution and to be independent of each other. A quantitative analysis of the relevance of such assumptions is important to help improving the exploitation of existing and upcoming multi-wavelength interferometric instruments. Analyze the statistical behaviour of both the absolute and the colour-differential squared visibilities: distribution laws, correlations and cross-correlations between different baselines. We use observations of stellar calibrators obtained with AMBER instrument on VLTI in different instrumental and observing configurations, from which we extract the frame-by-frame transfer function. Statistical hypotheses tests and diagnostics are then systematically applied. For both absolute and differential squared visibilities and under all instrumental and observing conditions, we find a better fit for the Student distribution than for the Gaussian, log-normal and Cauchy distributions. We find and analyze clear correlation effects caused by atmospheric perturbations. The differential squared visibilities allow to keep a larger fraction of data with respect to selected absolute squared visibilities and thus benefit from reduced temporal dispersion, while their distribution is more clearly characterized. The frame selection based on the criterion of a fixed SNR value might result in either a biased sample of frames or in a too severe selection.Comment: A&A, 13 pages and 9 figure

Reconstructing ice-sheet accumulation rates at ridge B, East Antarctica

Understanding how ice sheets responded to past climate change is fundamental to forecasting how they will respond in the future. Numerical models calculating the evolution of ice sheets depend upon accumulation data, which are principally available from ice cores. Here, we calculate past rates of ice accumulation using internal layering. The englacial structure of the East Antarctic ice divide at ridge B is extracted from airborne ice-penetrating radar. The isochronous surfaces are dated at their intersection with the Vostok ice-core site, where the depth–age relationship is known. The dated isochrons are used as input to a one-dimensional ice-flow model to investigate the spatial accumulation distribution. The calculations show that ice-accumulation rates generally increase from Vostok lake towards ridge B. The western flank of the ice divide experiences markedly more accumulation than in the east. Further, ice accumulation increases northwards along the ice divide. The results also show the variability of accumulation in time and space around the ridge B ice divide over the last 124 000 years

Spring protection in Southern KwaZulu Natal

Spring protection in Southern KwaZulu Nata

Atmospheric science

The following types of experiments for a proposed Space Station Microgravity Particle Research Facility are described: (1) growth of liquid water drop populations; (2) coalescence; (3) drop breakup; (4) breakup of freezing drops; (5) ice nucleation for large aerosols or bacteria; (6) scavenging of gases, for example, SO2 oxidation; (7) phoretic forces, i.e., thermophoresis versus diffusiophoresis; (8) Rayleigh bursting of drops; (9) charge separation due to collisions of rimed and unrimed ice; (10) charged drop dynamics; (11) growth of particles in other planetary atmospheres; and (12) freezing and liquid-liquid evaporation. The required capabilities and desired hardware for the facility are detailed

Millennial‐Scale Vulnerability of the Antarctic Ice Sheet to Regional Ice Shelf Collapse

The response of the Antarctic Ice Sheet to ice shelf collapse is explored with a high resolution ice sheet model. Rapid melting is applied to each of its major present day drainage basins in turn , to determine which parts of the ice sheet are most vulnerable to change in oceanic forcing, over the next 1000 years. We findthat West Antarctica can be largely deglaciated over a millenium, leading to more than two metres of sea level rise, if any of its major ice shelved disintegrated. The response of East Antarctica is more muted, but not negligible