Low emission zones: Effects on alternative-fuel vehicle uptake and fleet CO2 emissions

This study analyses the effect of a representative low-emission zone (LEZ) in Madrid on shifting vehicle registrations towards alternative fuel technologies and its effectiveness for reducing vehicle fleet CO2 emissions. Vehicle registration data is combined with real life fuel consumption values on individual vehicle model level, and the impact of the LEZ is then determined via an econometric approach. The increase in alternative fuel vehicles (AFV) registration shares due to the LEZ is found to be significant but fosters rather fossil fuel powered AFV and plug-in hybrid electric vehicles (PHEV) than zero emission vehicles. This is reflected in the average CO2 emissions of newly registered vehicles, which do not decrease significantly. In consequence, while the LEZ is a suitable measure for stimulating the shift towards low emission vehicles, a true zero emission zone would be required for effectively fostering also the decarbonization of the vehicle fleet

Hourly marginal electricity mixes and their relevance for assessing the environmental performance of installations with variable load or power

The ongoing energy transition is causing rapid changes in the electricity system and, in consequence, the environmental impacts associated with electricity generation. In parallel, the daily variability of generation increases with higher shares of renewable energies. This affects the potential environmental impacts or benefits of devices with variable load or power, such as electric vehicles, storage systems or photovoltaic home systems. However, recent environmental assessments of the actual benefit of such systems are scarce, with existing assessments majorly using average grid mixes that are frequently outdated and disregard the dynamic nature of renewable generation. This article provides detailed hourly average and marginal electricity mixes for each month of the year, determined for Spain as an illustrative country with a diversified (renewable) power generation portfolio that experienced a rapid change in the last years. These are combined with specific life-cycle emission factors for each generation technology. Main drivers for the impacts of the marginal mix turn out to be natural gas plants and imports, but also pumped hydropower due to its comparably low storage efficiency. Applied to a hypothetical photovoltaic rooftop installation, the differences between environmental assessments on hourly and on annual basis are found to be surprisingly low when assuming that the generated electricity replaces the average grid mix, but substantial when considering the marginal generation mix (i.e., the generation technologies that respond to a change in demand at a given time). This highlights the importance of considering the dynamics of the electricity system and the corresponding marginal electricity mixes when optimizing flexible load or generation technologies under environmental aspects

Revealing the Nature of Algol Disks through Optical and UV Spectroscopy, Synthetic Spectra, and Tomography of TT Hydrae

We have developed a systematic procedure to study the disks in Algol-type binaries using spectroscopic analysis, synthetic spectra, and tomography. We analyzed 119 H-alpha spectra of TT Hya, an Algol-type eclipsing interacting binary, collected from 1985-2001. The new radial velocities enabled us to derive reliable orbital elements, including a small non-zero eccentricity, and to improve the accuracy of the absolute dimensions of the system. High resolution IUE spectra were also analyzed to study the formation of the ultraviolet lines and continuum. Synthetic spectra of the iron curtain using our new shellspec program enabled us to derive a characteristic disk temperature of 7000K. We have demonstrated that the UV emission lines seen during total primary eclipse cannot originate from the accretion disk, but most likely arise from a hotter disk-stream interaction region. The synthetic spectra of the stars, disk, and stream allowed us to derive a lower limit to the mass transfer rate of 2e-10 solar masses per year. Doppler tomography of the observed H-alpha profiles revealed a distinct accretion disk. The difference spectra produced by subtracting the synthetic spectra of the stars resulted in an image of the disk, which virtually disappeared once the composite synthetic spectra of the stars and disk were used to calculate the difference spectra. An intensity enhancement of the resulting tomogram revealed images of the gas stream and an emission arc. We successfully modeled the gas stream using shellspec and associated the emission arc with an asymmetry in the accretion disk.Comment: 46 pages, 15 figures, 6 tables, accepted by Ap

Modeling the radial abundance distribution of the transition galaxy ngc 1313

NGC 1313 is the most massive disk galaxy showing a flat radial abundance distribution in its interstellar gas, a behavior generally observed in magellanic and irregular galaxies. We have attempted to reproduce this flat abundance distribution using a multiphase chemical evolution model, which has been previously used sucessfully to depict other spiral galaxies along the Hubble morphological sequence. We found that it is not possible to reproduce the flat radial abundance distribution in NGC 1313, and at the same time, be consistent with observed radial distributions of other key parameters such the surface gas density and star formation profiles. We conclude that a more complicated galactic evolution model including radial flows, and possibly mass loss due to supernova explosions and winds, is necessary to explain the apparent chemical uniformity of the disk of NGC 1313Comment: 14 paginas, 4 figures, to be published in ApJ, apri

A Instituição de Gota de Leche na província de Toledo (1906-1966)

The objective of this historical investigation is to discover if the Institution called "La Gota de Leche" existed in Toledo. Methodology by means of the heuristic method, the historical press is analyzed and other primary archival sources are reviewed. Results, although its creation was tedious and its operation was subject to criticism, its benefits were soon seen through the maternal and child health indicators. The institution between 1906 and 1966, was present in both the urban and rural areas of Toledo. Since the creation the mother received health care throughout the gestational period; she acquired habits on child hygiene and obtained health education to establish adequate breastfeeding. Conclusion La Gota de Leche Toledana was a School of Childcare and Maternology, a fact that allowed to carry out prevention, care and education activities throughout the gestational period. Thus, the results obtained were extremely satisfactory, since it was possible to reduce infant mortality during the first half of the 20th century, through the improvement of maternal and child health indicators.El objetivo de esta investigación histórica es descubrir sí en Toledo existió la Institución denominada «La Gota de Leche». Metodología por medio del método heurístico se analiza la prensa histórica y se revisan otras fuentes primarias archivísticas. Resultados, aunque su creación fue tediosa y su funcionamiento estuvo sujeto a críticas, sus beneficios pronto se dejaron ver, a través de los indicadores salud materno-infantil. La institución entre 1906 y 1966, estuvo presente tanto en el ámbito urbano como rural de Toledo. Desde la creación la madre recibía atención sanitaria durante todo el periodo gestacional; adquiría hábitos sobre higiene infantil y obtenía educación sanitaria para establecer una lactancia materna adecuada. Conclusión La Gota de Leche Toledana fue una Escuela de Puericultura y Maternología, hecho que permitió llevar a cabo actividades de prevención, asistencia y educación durante todo el periodo gestacional. De modo que los resultados obtenidos fuero sumamente satisfactorios, pues se logró reducir la mortalidad infantil durante la primera mitad del siglo XX, a través de la mejoría de los indicadores de la salud materno-infantil.O objetivo desta investigação histórica é descobrir se a Instituição chamada "La Gota de Leche" existia em Toledo. Metodologia por meio do método heurístico, a imprensa histórica é analisada e outras fontes arquivísticas primárias são revisadas. Resultados, embora sua criação tenha sido tediosa e seu funcionamento sujeito a críticas, seus benefícios logo foram percebidos através dos indicadores de saúde materno-infantil. A instituição entre 1906 e 1966, esteve presente tanto na zona urbana como rural de Toledo. Desde a criação a mãe recebeu cuidados de saúde durante todo o período gestacional; adquiriu hábitos de higiene infantil e obteve educação em saúde para estabelecer o aleitamento materno adequado. Conclusão La Gota de Leche Toledana foi uma Escola de Puericultura e Maternologia, fato que possibilitou a realização de atividades de prevenção, cuidado e educação durante todo o período gestacional. Assim, os resultados obtidos foram extremamente satisfatórios, uma vez que foi possível reduzir a mortalidade infantil durante a primeira metade do século 20, por meio da melhoria dos indicadores de saúde materno-infantil

UBVRI Light Curves of 44 Type Ia Supernovae

We present UBVRI photometry of 44 type-Ia supernovae (SN Ia) observed from 1997 to 2001 as part of a continuing monitoring campaign at the Fred Lawrence Whipple Observatory of the Harvard-Smithsonian Center for Astrophysics. The data set comprises 2190 observations and is the largest homogeneously observed and reduced sample of SN Ia to date, nearly doubling the number of well-observed, nearby SN Ia with published multicolor CCD light curves. The large sample of U-band photometry is a unique addition, with important connections to SN Ia observed at high redshift. The decline rate of SN Ia U-band light curves correlates well with the decline rate in other bands, as does the U-B color at maximum light. However, the U-band peak magnitudes show an increased dispersion relative to other bands even after accounting for extinction and decline rate, amounting to an additional ~40% intrinsic scatter compared to B-band.Comment: 84 authors, 71 pages, 51 tables, 10 figures. Accepted for publication in the Astronomical Journal. Version with high-res figures and electronic data at http://astron.berkeley.edu/~saurabh/cfa2snIa

Microbiota-derived short chain fatty acids modulate microglia and promote Aβ plaque deposition.

Previous studies have identified a crucial role of the gut microbiome in modifying Alzheimer's disease (AD) progression. However, the mechanisms of microbiome-brain interaction in AD were so far unknown. Here, we identify microbiota-derived short chain fatty acids (SCFA) as microbial metabolites which promote Aβ deposition. Germ-free (GF) AD mice exhibit a substantially reduced Aβ plaque load and markedly reduced SCFA plasma concentrations; conversely, SCFA supplementation to GF AD mice increased the Aβ plaque load to levels of conventionally colonized (specific pathogen-free [SPF]) animals and SCFA supplementation to SPF mice even further exacerbated plaque load. This was accompanied by the pronounced alterations in microglial transcriptomic profile, including upregulation of ApoE. Despite increased microglial recruitment to Aβ plaques upon SCFA supplementation, microglia contained less intracellular Aβ. Taken together, our results demonstrate that microbiota-derived SCFA are critical mediators along the gut-brain axis which promote Aβ deposition likely via modulation of the microglial phenotype