Inverse modeling and mapping US air quality influences of inorganic PM_(2.5) precursor emissions using the adjoint of GEOS-Chem

Influences of specific sources of inorganic PM_(2.5) on peak and ambient aerosol concentrations in the US are evaluated using a combination of inverse modeling and sensitivity analysis. First, sulfate and nitrate aerosol measurements from the IMPROVE network are assimilated using the four-dimensional variational (4D-Var) method into the GEOS-Chem chemical transport model in order to constrain emissions estimates in four separate month-long inversions (one per season). Of the precursor emissions, these observations primarily constrain ammonia (NH_3). While the net result is a decrease in estimated US~NH_3 emissions relative to the original inventory, there is considerable variability in adjustments made to NH_3 emissions in different locations, seasons and source sectors, such as focused decreases in the midwest during July, broad decreases throughout the US~in January, increases in eastern coastal areas in April, and an effective redistribution of emissions from natural to anthropogenic sources. Implementing these constrained emissions, the adjoint model is applied to quantify the influences of emissions on representative PM_(2.5) air quality metrics within the US. The resulting sensitivity maps display a wide range of spatial, sectoral and seasonal variability in the susceptibility of the air quality metrics to absolute emissions changes and the effectiveness of incremental emissions controls of specific source sectors. NH_3 emissions near sources of sulfur oxides (SO_x) are estimated to most influence peak inorganic PM_(2.5) levels in the East; thus, the most effective controls of NH_3 emissions are often disjoint from locations of peak NH_3 emissions. Controls of emissions from industrial sectors of SO_x and NO_x are estimated to be more effective than surface emissions, and changes to NH_3 emissions in regions dominated by natural sources are disproportionately more effective than regions dominated by anthropogenic sources. NOx controls are most effective in northern states in October; in January, SO_x controls may be counterproductive. When considering ambient inorganic PM_(2.5) concentrations, intercontinental influences are small, though transboundary influences within North America are significant, with SO_x emissions from surface sources in Mexico contributing almost a fourth of the total influence from this sector

Adaptation “in the Wild”: Ontology-Based Personalization of Open-Corpus Learning Material

Abstract. Teacher and students can use WWW as a limitless source of learning material for nearly any subject. Yet, such abundance of content comes with the problem of finding the right piece at the right time. Conventional adaptive educational systems cannot support personalized access to open-corpus learning material as they rely on manually constructed content models. This paper presents an approach to this problem that does not require intervention from a human expert. The approach has been implemented in an adaptive system that recommends students supplementary reading material and adaptively annotates it. The results of the evaluation experiment have demonstrated several significant effects of using the system on students ’ learning

Adaptation “in the Wild”: Ontology-Based Personalization of Open-Corpus Learning Material

Teacher and students can use WWW as a limitless source of learning material for nearly any subject. Yet, such abundance of content comes with the problem of finding the right piece at the right time. Conventional adaptive educational systems cannot support personalized access to open-corpus learning material as they rely on manually constructed content models. This paper presents an approach to this problem that does not require intervention from a human expert. The approach has been implemented in an adaptive system that recommends students supplementary reading material and adaptively annotates it. The results of the evaluation experiment have demonstrated several significant effects of using the system on students’ learning.\u

Erhebung der Grundlagen für die bessere Vermarktung von nach besonderen Richtlinien erzeugten landwirtschaftlichen Produkten aus dem Oberrheingebiet

Die vorliegende Untersuchung basiert auf einer Situationsanalyse der Produktions- und Marktstrukturen der regionalen Landwirtschaft. Neben dem Nachfrageverhalten sowie den Erwartungen und Wünschen der Verbraucher und regionalen Marktpartner der Landwirtschaft (Mikroumfeld) werden zudem übergeordnete physische, gesellschaftliche, politische und ökonomische Faktoren (Makroumfeld), die die Ausrichtung der regionalen Landwirtschaft beeinflussen, betrachtet. Die Analyse des Mikro- und Makroumfeldes setzt sich aus folgenden Projektteilen zusammen: - Analyse der landwirtschaftlichen Produktion und ihres Umfeldes, - Analyse der landwirtschaftlichen Vermarktungsstruktur und des Grades der Vernetzung der Landwirtschaft mit ihren regionalen Marktpartnern, - Analyse des Kaufverhaltens und der Präferenzen bei Verbrauchern bezüglich regional und umweltgerecht erzeugter Produkte in verschiedenen Markttypen (Biomarkt/ Naturkostgeschäft, Supermarkt sowie Verbrauchermarkt/Einkaufszentrum), - Analyse des Grossverbrauchermarktes (Einrichtungen der Gemeinschaftsverpflegung) hinsichtlich des Einsatzes von regionalen und umweltgerecht erzeugten Agrarprodukten, - Untersuchung der grenzüberschreitenden Aktivitäten der Landwirtschaft und ihrer Marktpartner in der REGIO, - Systematisierung und Bewertung der handelsrechtlichen Hemmnisse im grenzüberschreitenden Warenaustausch. Da die Bedeutung einzelner Produktgruppen, wie auch einzelner Vermarktungswege im Untersuchungsgebiet variieren, konzentriert sich die Untersuchung auf die für die drei Regionen jeweils wichtigsten Nahrungsmittelmärkte Brotgetreide, Milch, Fleisch sowie Obst und Gemüse. Zusätzlich werden produktübergreifend die Märkte für integriert sowie für ökologisch erzeugte Nahrungsmittel analysiert. Aufbauend auf die im Rahmen dieser Arbeit erstellten Umfeldanalyse sowie die Schätzung der weiteren Entwicklung der wichtigsten Einflussfaktoren der landwirtschaftlichen Erzeugung und Vermarktung, werden, mit Hilfe einer produktbezogenen Betrachtung der fördernden und hemmenden Faktoren, die Möglichkeiten für eine stärkere regionale Marktausrichtung der Landwirtschaft unter besonderer Berücksichtigung der ökologischen und integrierten Produktion beurteilt

Assessment of the tissue distribution of transplanted human endothelial progenitor cells by radioactive labeling

Background— Transplantation of endothelial progenitor cells (EPCs) improves vascularization and left ventricular function after experimental myocardial ischemia. However, tissue distribution of transplanted EPCs has not yet been monitored in living animals. Therefore, we tested whether radioactive labeling allows us to detect injected EPCs

Global modeling of secondary organic aerosol formation from aromatic hydrocarbons: high- vs low-yield pathways

Formation of SOA from the aromatic species toluene, xylene, and, for the first time, benzene, is added to a global chemical transport model. A simple mechanism is presented that accounts for competition between low and high-yield pathways of SOA formation, wherein secondary gas-phase products react further with either nitrogen oxide (NO) or hydroperoxy radical (HO2) to yield semi- or non-volatile products, respectively. Aromatic species yield more SOA when they react with OH in regions where the [NO]/[HO2] ratios are lower. The SOA yield thus depends upon the distribution of aromatic emissions, with biomass burning emissions being in areas with lower [NO]/[HO2] ratios, and the reactivity of the aromatic with respect to OH, as a lower initial reactivity allows transport away from industrial source regions, where [NO]/[HO2] ratios are higher, to more remote regions, where this ratio is lower and, hence, the ultimate yield of SOA is higher. As a result, benzene is estimated to be the most important aromatic species with regards to formation of SOA, with a total production nearly equal that of toluene and xylene combined. In total, while only 39% percent of the aromatic species react via the low-NOx pathway, 72% of the aromatic SOA is formed via this mechanism. Predicted SOA concentrations from aromatics in the Eastern United States and Eastern Europe are actually largest during the summer, when the [NO]/[HO2] ratio is lower. Global production of SOA from aromatic sources is estimated at 3.5 Tg/yr, resulting in a global burden of 0.08 Tg, twice as large as previous estimates. The contribution of these largely anthropogenic sources to global SOA is still small relative to biogenic sources, which are estimated to comprise 90% of the global SOA burden, about half of which comes from isoprene. Compared to recent observations, it would appear there are additional pathways beyond those accounted for here for production of anthropogenic SOA. However, owing to differences in spatial distributions of sources and seasons of peak production, there are still regions in which aromatic SOA produced via the mechanisms identified here are predicted to contribute substantially to, and even dominate, the local SOA concentrations, such as outflow regions from North America and South East Asia during the wintertime, though total SOA concentrations there are small (~0.1 μg/m^³)

J004457+4123 (Sharov 21): not a remarkable nova in M31 but a background quasar with a spectacular UV flare

We announce the discovery of a quasar behind the disk of M31, which was previously classified as a remarkable nova in our neighbour galaxy. The paper is primarily aimed at the outburst of J004457+4123 (Sharov 21), with the first part focussed on the optical spectroscopy and the improvement in the photometric database. Both the optical spectrum and the broad band spectral energy distribution of Sharov 21 are shown to be very similar to that of normal, radio-quiet type 1 quasars. We present photometric data covering more than a century and resulting in a long-term light curve that is densely sampled over the past five decades. The variability of the quasar is characterized by a ground state with typical fluctuation amplitudes of ~0.2 mag around B~20.5, superimposed by a singular flare of ~2 yr duration (observer frame) with the maximum at 1992.81 where the UV flux has increased by a factor of ~20. The total energy in the flare is at least three orders of magnitudes higher than the radiated energy of the most luminous supernovae, provided that it comes from an intrinsic process and the energy is radiated isotropically. The profile of the flare light curve appears to be in agreement with the standard predictions for a stellar tidal disruption event where a ~10 M_sun giant star was shredded in the tidal field of a ~2...5 10^8 M_sun black hole. The short fallback time derived from the light curve requires an ultra-close encounter where the pericentre of the stellar orbit is deep within the tidal disruption radius. Gravitational microlensing provides an alternative explanation, though the probability of such a high amplification event is very low.Comment: Accepted for publication in Astronomy and Astrophysics, 14 pages, 11 figure