How Lyman Alpha Emission Depends On Galaxy Stellar Mass

In this work, we show how the stellar mass (M) of galaxies affects the 3<z<4.6 Ly-alpha equivalent width (EW) distribution. To this end, we design a sample of 629 galaxies in the M range 7.6 < logM/Msun < 10.6 from the 3D-HST/CANDELS survey. We perform spectroscopic observations of this sample using the Michigan/Magellan Fiber System, allowing us to measure Ly-alpha fluxes and use 3D-HST/CANDELS ancillary data. In order to study the Ly-alpha EW distribution dependence on M, we split the whole sample in three stellar mass bins. We find that, in all bins, the distribution is best represented by an exponential profile of the form dN(M)/dEW= A(M)exp(-EW/W0(M))/W0(M). Through a Bayesian analysis, we confirm that lower M galaxies have higher Ly-alpha EWs. We also find that the fraction A of galaxies featuring emission and the e-folding scale W0 of the distribution anti- correlate with M, recovering expressions of the forms A(M)= -0.26(.13) logM/Msun+3.01(1.2) and W0(M)= -15.6(3.5) logM/Msun +166(34). These results are crucial for proper interpretation of Ly-alpha emission trends reported in the literature that may be affected by strong M selection biases.Comment: 4 pages, 5 figure

Preliminary results from an advanced lighting controls testbed

Abstract Preliminary results from a large-scale testbed of advanced lighting control technologies at the Phillip Burton Federal Building at 450 Golden Gate Ave. in San Francisco are presented. The first year objective of this project is to determine the sustainable energy savings and cost-effectiveness of different lighting control technologies compared to a portion of the building where only minimal controls are installed. The paper presents the analyzed results from six months of tests focused on accurately characterizing the energy savings potential of one type of daylight-linked lighting controls compared to the lighting in similar open-planned areas without dimming controls. After analyzing a half year&apos;s data, we determined that the annual energy savings for this type of daylightlinked controls was 41% and 30% for the outer rows of lights on the South and North sides of the building, respectively. The annual energy savings dropped to 22% and 16% for the second row of lights for the South and North, respectively, and was negligible for the third rows of lights

Increased Reactive Oxygen Species and Cell Cycle Defects Contribute to Anemia in the RASA3 Mutant Mouse Model s

RASA3 is a Ras GTPase activating protein that plays a critical role in blood formation. The autosomal recessive mouse model scat (severe combined anemia and thrombocytopenia) carries a missense mutation in Rasa3. Homozygotes present with a phenotype characteristic of bone marrow failure that is accompanied by alternating episodes of crisis and remission. The mechanism leading to impaired erythropoiesis and peripheral cell destruction as evidenced by membrane fragmentation in scat is unclear, although we previously reported that the mislocalization of RASA3 to the cytosol of reticulocytes and mature red cells plays a role in the disease. In this study, we further characterized the bone marrow failure in scat and found that RASA3 plays a central role in cell cycle progression and maintenance of reactive oxygen species (ROS) levels during terminal erythroid differentiation, without inducing apoptosis of the precursors. In scat mice undergoing crises, there is a consistent pattern of an increased proportion of cells in the G0/G1 phase at the basophilic and polychromatophilic stages of erythroid differentiation, suggesting that RASA3 is involved in the G1 checkpoint. However, this increase in G1 is transient, and either resolves or becomes indiscernible by the orthochromatic stage. In addition, while ROS levels are normal early in erythropoiesis, there is accumulation of superoxide levels at the reticulocyte stage (DHE increased 40% in scat; p = 0.02) even though mitochondria, a potential source for ROS, are eliminated normally. Surprisingly, apoptosis is significantly decreased in the scat bone marrow at the proerythroblastic (15.3%; p = 0.004), polychromatophilic (8.5%; p = 0.01), and orthochromatic (4.2%; p = 0.02) stages. Together, these data indicate that ROS accumulation at the reticulocyte stage, without apoptosis, contributes to the membrane fragmentation observed in scat. Finally, the cell cycle defect and increased levels of ROS suggest that scat is a model of bone marrow failure with characteristics of aplastic anemia

Benefit of GEOSS Interoperability in Assessment of Environmental Impacts Illustrated by the Case of Photovoltaic Systems

International audienceAssessment of environmental impacts of a power system exploiting a renewable energy needs a large number of geographically-dependent data and of technological data. These data are located in various sources and available in various formats. To avoid the burden of data collection and reformatting, we exploit the interoperability capabilities set up in GEOSS and combine them with other GEOSS-compliant components proposed by projects funded by the European Commission. This is illustrated by the case of photovoltaic systems. A Web-based tool links the various sources of data and executes several models to offer various impacts factors in different areas: human health, climate change, primary energy, ecosystems

Environmental impact assessment of electricity production by photovoltaic system using GEOSS recommendations on interoperability

International audienceWithin the Architecture Implementation Pilot (AIP-3) of GEOSS, we have developed a scenario called "environmental impact assessment of the production, transportation and use of energy for the photovoltaic (PV) sector through Life Cycle Assessment (LCA)". It aims at providing decision-makers and policy-planners with reliable and geo-localized knowledge of several impacts induced by various technologies of the PV sector. The scenario is implemented in the GEOSS Common Infrastructure (GCI) and benefits from the GEOSS interoperability arrangements. The FP7-co-funded EnerGEO project provides a GEOSS compliant Catalogue Service for the Web (CSW) that permits to discover the Web Processing Service (WPS) allowing computation of the environmental impact. A WebGIS client provided by the FP7-co-funded GENESIS platform allows users to interact with geospatial data and computation processes. This scenario has proven to be an efficient tool to disseminate knowledge on environmental impacts related to PV because of the GEOSS capabilities in interoperability

The HETDEX Pilot Survey III: The Low Metallicities of High-Redshift Lyman Alpha Galaxies

We present Keck/NIRSPEC spectroscopic observations of three Lyman alpha emitting galaxies (LAEs) at z ~ 2.3 discovered with the HETDEX pilot survey. We detect Halpha, [OIII], and Hbeta emission from two galaxies at z = 2.29 and 2.49, designated HPS194 and HPS256, respectively, representing the first detection of multiple rest-frame optical emission lines in galaxies at high-redshift selected on the basis of their Lyman alpha emission. The redshifts of the Lyman alpha emission from these galaxies are offset redward of the systemic redshifts by Delta_v = 162 +/- 37 (photometric) +/- 42 (systematic) km/s for HPS194, and Delta_v = 36 +/- 35 +/- 18 km/s for HPS256. An interpretation for HPS194 is that a large-scale outflow may be occurring in its interstellar medium. The emission line ratios imply that neither LAE hosts an active galactic nucleus. Using the upper limits on the [NII] emission we place meaningful constraints on the gas-phase metallicities in these two LAEs of Z < 0.17 and < 0.28 Zsol (1 sigma). Measuring the stellar masses of these objects via spectral energy distribution (SED) fitting (~ 10^10 and 6 x 10^8 Msol, respectively), we study the nature of LAEs in a mass-metallicity plane. At least one of these two LAEs appears to be more metal poor than continuum-selected star-forming galaxies at the same redshift and stellar mass, implying that objects exhibiting Lyman alpha emission may be systematically less chemically enriched than the general galaxy population. We use the SEDs of these two galaxies to show that neglecting the emission lines when fitting stellar population models to the observed photometry can result in overestimates of the population age by orders of magnitude, and the stellar mass by a factor of ~ 2. This effect is particularly important at z > 7, where similarly strong emission lines may masquerade in the photometry as a 4000 A break (abridged).Comment: Replaced with the accepted (to ApJ) versio