Simulating Reionization: Character and Observability

In recent years there has been considerable progress in our understanding of the nature and properties of the reionization process. In particular, the numerical simulations of this epoch have made a qualitative leap forward, reaching sufficiently large scales to derive the characteristic scales of the reionization process and thus allowing for realistic observational predictions. Our group has recently performed the first such large-scale radiative transfer simulations of reionization, run on top of state-of-the-art simulations of early structure formation. This allowed us to make the first realistic observational predictions about the Epoch of Reionization based on detailed radiative transfer and structure formation simulations. We discuss the basic features of reionization derived from our simulations and some recent results on the observational implications for the high-redshift Ly-alpha sources.Comment: 3 pages, to appear in the Proceedings of First Stars III, Santa Fe, July 2007, AIP Conference Serie

Gene expression analysis indicates CB1 receptor upregulation in the hippocampus and neurotoxic effects in the frontal cortex 3 weeks after single-dose MDMA administration in Dark Agouti rats.

BACKGROUND: 3,4-methylenedioxymethamphetamine (MDMA, "ecstasy") is a widely used recreational drug known to impair cognitive functions on the long-run. Both hippocampal and frontal cortical regions have well established roles in behavior, memory formation and other cognitive tasks and damage of these regions is associated with altered behavior and cognitive functions, impairments frequently described in heavy MDMA users. The aim of this study was to examine the hippocampus, frontal cortex and dorsal raphe of Dark Agouti rats with gene expression arrays (Illumina RatRef bead arrays) looking for possible mechanisms and new candidates contributing to the effects of a single dose of MDMA (15 mg/kg) 3 weeks earlier. RESULTS: The number of differentially expressed genes in the hippocampus, frontal cortex and the dorsal raphe were 481, 155, and 15, respectively. Gene set enrichment analysis of the microarray data revealed reduced expression of 'memory' and 'cognition', 'dendrite development' and 'regulation of synaptic plasticity' gene sets in the hippocampus, parallel to the upregulation of the CB1 cannabinoid- and Epha4, Epha5, Epha6 ephrin receptors. Downregulated gene sets in the frontal cortex were related to protein synthesis, chromatin organization, transmembrane transport processes, while 'dendrite development', 'regulation of synaptic plasticity' and 'positive regulation of synapse assembly' gene sets were upregulated. Changes in the dorsal raphe region were mild and in most cases not significant. CONCLUSION: The present data raise the possibility of new synapse formation/synaptic reorganization in the frontal cortex three weeks after a single neurotoxic dose of MDMA. In contrast, a prolonged depression of new neurite formation in the hippocampus is suggested by the data, which underlines the particular vulnerability of this brain region after the drug treatment. Finally, our results also suggest the substantial contribution of CB1 receptor and endocannabinoid mediated pathways in the hippocampal impairments. Taken together the present study provides evidence for the participation of new molecular candidates in the long-term effects of MDMA

Skull thickening, paranasal sinus expansion, and sella turcica shrinkage from chronic intracranial hypotension

In children or young adults, the morphology of the skull can be altered by excessive drainage of CSF following placement of a ventriculoperitoneal (VP) shunt. In Sunken Eyes, Sagging Brain Syndrome, gradual enlargement of the orbital cavity occurs from low or negative intracranial pressure (ICP), leading to progressive bilateral enophthalmos. The authors report several heretofore unrecognized manifestations of this syndrome, which developed in a 29-year-old man with a history of VP shunt placement following a traumatic brain injury at the age of 9 years. Magnetic resonance imaging showed typical features of chronic intracranial hypotension, and lumbar puncture yielded an unrecordable subarachnoid opening pressure. The calvaria was twice its normal thickness, owing to contraction of the inner table. The paranasal sinuses were expanded, with aeration of the anterior clinoid processes, greater sphenoid wings, and temporal bones. The sella turcica showed a 50% reduction in cross-sectional area as compared with that in control subjects, resulting in partial extrusion of the pituitary gland. These new features broaden the spectrum of clinical findings associated with low ICP. Secondary installation of a valve to restore normal ICP is recommended to halt progression of these rare complications of VP shunt placement

Molecular gas along a bright Hα\alpha filament in 2A 0335+096 revealed by ALMA

We present ALMA CO(1–0) and CO(3–2) observations of the brightest cluster galaxy (BCG) in the 2A 0335+096 galaxy cluster ($z$ = 0.0346). The total molecular gas mass of 1.13 ± 0.15 × 10$^9$ $M_\odot$ is divided into two components: a nuclear region and a 7 kpc long dusty filament. The central molecular gas component accounts for 3.2 ± 0.4 × 10$^8$ $M_\odot$ of the total supply of cold gas. Instead of forming a rotationally supported ring or disk, it is composed of two distinct, blueshifted clumps south of the nucleus and a series of low-significance redshifted clumps extending toward a nearby companion galaxy. The velocity of the redshifted clouds increases with radius to a value consistent with the companion galaxy, suggesting that an interaction between these galaxies <20 Myr ago disrupted a pre-existing molecular gas reservoir within the BCG. Most of the molecular gas, 7.8 ± 0.9 × 10$^8$ $M_\odot$, is located in the filament. The CO emission is co-spatial with a 10$^4$ K emission-line nebula and soft X-rays from 0.5 keV gas, indicating that the molecular gas has cooled out of the intracluster medium over a period of 25–100 Myr. The filament trails an X-ray cavity, suggesting that the gas has cooled from low-entropy gas that has been lifted out of the cluster core and become thermally unstable. We are unable to distinguish between inflow and outflow along the filament with the present data. Cloud velocities along the filament are consistent with gravitational free-fall near the plane of the sky, although their increasing blueshifts with radius are consistent with outflow.Support for this work was provided in part by the National Aeronautics and Space Administration through Chandra Award Number G05-16134X issued by the Smithsonian Astrophysical Observatory for an on behalf of the National Aeronautics and Space Administration under contract NAS8- 03060. A.N.V. and B.R.M. acknowledge support from the Natural Sciences and Engineering Research Council of Canada. B.R.M. further acknowledges support from the Canadian Space Agency Space Science Enhancement Program

Comparison of Timing of IUI in Ovarian Stimulated Cycles

[[abstract]]This study was conducted to compare pregnancy rates following two different timings of intrauterine insemination (IUI) in ovarian stimulated cycles. This retrospective study included 135 couples undergoing treatment for infertility. IUI was performed at either 24 hr or 36 hr after hCG injection. Pregnancy rates did not differ between the two groups or in subgroups receiving different methods of ovarian stimulation. Pregnancy rates were similar when IUI was performed at either 24 or 36 hr after hCG injection in ovarian stimulated cycles.[[notice]]補正完

Soil Water Depletion by Eucalyptus spp. Integrated into Dryland Agricultural Systems

Spatial patterns of soil water depletion by Eucalyptus spp. were surveyed to assess the potential of tree belts and short rotation phase farming with trees for groundwater recharge reduction and salinity control. Soils were sampled to depths of up to 10 m in transects perpendicular to 4- to 7-year-old mallee eucalypt belts (Eucalyptus horistes, E. kochii ssp. plenissima, E. loxophleba ssp. lissophloia, E. polybractea) and in a 4 year-old block of E. astringens. Results indicate that the eucalypt species can exploit soil water to depths of at least 8–10 m within 7 years of planting. The root systems of these eucalypts were able to penetrate clayey subsoils with bulk densities of up to 2.0 g cm−3. Leaf area indexes of tree belts were 2–10 times greater than those predicted for natural vegetation, probably as a result of exploiting a greater amount of soil water stored under the agricultural system. The lateral influence of mallee belts, as indicated by soil water contents that were depleted to wilting point, ranged from 15–42 m. The resulting dry soil zone provided an effective barrier to groundwater recharge by incident rainfall thereby lessening the risk of salinisation in the agricultural landscape. The width of this barrier to recharge was predicted to range from 7 m to 54 m based on leaf area