131 research outputs found

    FDA Drug Approvals: Time Is Money!

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    We investigated the stock price behavior of public pharmaceutical and biotechnology companies upon approval of a drug by the Food and Drug Administration (FDA). Using event study methodology, we examine the reaction caused by the approval, seperating it from the asset price movements caused by other factors such as market and industry effects. The results are then used to validate the model developed in this article as an alternative to the explanations given by Sharma and Lacey (2004). The results of this study support the Efficient Market Hypothesis, i.e. that the market reacts to the new information quickly and clearly

    Dynamic Pricing on Two-Sided Platforms: Consequences on Customers’ Fairness Perceptions and Purchase Intentions

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    Technological advancements simplify the application of dynamic pricing, i.e., the flexible and rapid adjustment of prices to changes in demand. Consequently, companies increasingly use dynamic pricing in their business models, although research reports negative consequences on customer fairness perceptions. This holds not only for one-sided businesses, but also for popular two-sided platforms. However, these platforms differ from one-sided businesses in that the total prices paid by customers consist of product prices and platform fees – and both price components can be dynamically adjusted. In an online experiment, we examine customers’ fairness perceptions and purchase intentions when product price and platform fee change dynamically. We find that dynamic price increases reduce fairness perceptions and purchase intentions, while the cause of the price increases is irrelevant to customers. These results indicate an imbalance in the risks and benefits of dynamic pricing between the pricing strategies of the platform and the provider

    Towards a simulation of minibuses in South Africa

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    After private cars, minibus taxis are the most common transport mode in South Africa. Especially for low-income citizens living in townships, minibus services are often the only possibility for mobility. Despite the great importance of the mode, there is very little knowledge of routes, fares, and the number of minibuses. Hence, it is difficult to simulate and to understand the influence of this mode on other modes and on transport planning in general.. is article presents the development of the first "close-to-reality" minibus supply model based on demand and street network only The approach adopts the survival-of-the-fittest principle, using a co-evolutionary algorithm that is integrated into a microscopic multi-agent simulation framework The successful application of the approach to a large-scale, real-world scenario in the Nelson Mandela Bay Area Municipality in South Africa shows that it is able to identify the main minibus corridors as well as to find robust service coverage in lower-demand areas The resulting minibus supply model can then be used for planning purposes (e.g., to investigate aspects of strategic, operational, or regulatory changes)

    BiodiversitÀtsrelevante Regelungen zur nationalen Umsetzung des Greenings der Gemeinsamen Agrarpolitik der EU nach 2013

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    In der vorliegenden Stellungnahme werden die GAP-BeschlĂŒsse zum Greening der Direktzahlungen in Bezug auf die nationalen GestaltungsspielrĂ€ume fĂŒr die drei Greening-Komponenten Anbaudiversifizierung, Erhaltung von DauergrĂŒnland und ökologische VorrangflĂ€chen (ÖVF)2 bewertet und Handlungsoptionen vorgeschlagen. Dabei wird der Frage nachgegangen, inwiefern die einzelnen nationalen Umsetzungsoptionen sich auf die BiodiversitĂ€t auswirken und welche Kosten mit einzelnen ÖVF-Maßnahmen verbunden sind. Weiterhin wird der administrative Aufwand bewertet

    Haplotyping, linkage mapping and expression analysis of barley genes regulated by terminal drought stress influencing seed quality

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    <p>Abstract</p> <p>Background</p> <p>The increasingly narrow genetic background characteristic of modern crop germplasm presents a challenge for the breeding of cultivars that require adaptation to the anticipated change in climate. Thus, high priority research aims at the identification of relevant allelic variation present both in the crop itself as well as in its progenitors. This study is based on the characterization of genetic variation in barley, with a view to enhancing its response to terminal drought stress.</p> <p>Results</p> <p>The expression patterns of drought regulated genes were monitored during plant ontogeny, mapped and the location of these genes was incorporated into a comprehensive barley SNP linkage map. Haplotypes within a set of 17 starch biosynthesis/degradation genes were defined, and a particularly high level of haplotype variation was uncovered in the genes encoding sucrose synthase (types I and II) and starch synthase. The ability of a panel of 50 barley accessions to maintain grain starch content under terminal drought conditions was explored.</p> <p>Conclusion</p> <p>The linkage/expression map is an informative resource in the context of characterizing the response of barley to drought stress. The high level of haplotype variation among starch biosynthesis/degradation genes in the progenitors of cultivated barley shows that domestication and breeding have greatly eroded their allelic diversity in current elite cultivars. Prospective association analysis based on core drought-regulated genes may simplify the process of identifying favourable alleles, and help to understand the genetic basis of the response to terminal drought.</p

    Enhanced sulfur in the upper troposphere and lower stratosphere in spring 2020

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    Sulfur compounds in the upper troposphere and lower stratosphere (UTLS) impact the atmosphere radiation budget, either directly as particles or indirectly as precursor gas for new particle formation. In situ measurements in the UTLS are rare but are important to better understand the impact of the sulfur budget on climate. The BLUESKY mission in May and June 2020 explored an unprecedented situation. (1) The UTLS experienced extraordinary dry conditions in spring 2020 over Europe, in comparison to previous years, and (2) the first lockdown of the COVID-19 pandemic caused major emission reductions from industry, ground, and airborne transportation. With the two research aircraft HALO and Falcon, 20 flights were conducted over central Europe and the North Atlantic to investigate the atmospheric composition with respect to trace gases, aerosol, and clouds. Here, we focus on measurements of sulfur dioxide (SO2_{2}) and particulate sulfate (SO2−^{2-}4_{4}) in the altitude range of 8 to 14.5 km which show unexpectedly enhanced mixing ratios of SO2_{2} in the upper troposphere and of SO2−^{2-}4_{4} in the lowermost stratosphere. In the UT, we find SO2_{2} mixing ratios of (0.07±0.01) ppb, caused by the remaining air traffic, and reduced SO2_{2} sinks due to low OH and low cloud fractions and to a minor extent by uplift from boundary layer sources. Particulate sulfate showed elevated mixing ratios of up to 0.33 ppb in the LS. We suggest that the eruption of the volcano Raikoke in June 2019, which emitted about 1 Tg SO2_{2} into the stratosphere in northern midlatitudes, caused these enhancements, in addition to Siberian and Canadian wildfires and other minor volcanic eruptions. Our measurements can help to test models and lead to new insights in the distribution of sulfur compounds in the UTLS, their sources, and sinks. Moreover, these results can contribute to improving simulations of the radiation budget in the UTLS with respect to sulfur effects

    QTL mapping for resistance against cereal cyst nematode (Heterodera avenae Woll.) in wheat (Triticum aestivum L.)

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    The resistance to cereal cyst nematode (Heterodera avenae Woll.) in wheat (Triticum aestivum L.) was studied using 114 doubled haploid lines from a novel ITMI mapping population. These lines were screened for nematode infestation in a controlled environment for two years. QTL-mapping analyses were performed across two years (Y1 and Y2) as well as combining two years (CY) data. On the 114 lines that were screened, a total of 2,736 data points (genotype, batch or years, and replication combinations) were acquired. For QTL analysis, 12,093 markers (11,678 SNPs and 415 SSRs markers) were used, after filtering the genotypic data, for the QTL mapping. Composite interval mapping, using Haley-Knott regression (hk) method in R/QTL, was used for QTL analysis. In total, 19 QTLs were detected out of which 13 were novel and six were found to be colocalized or nearby to previously reported Cre genes, QTLs or MTAs for H. avenae or H. filipjevi. Nine QTLs were detected across all three groups (Y1, Y2 and CY) including a significant QTL "QCcn.ha-2D" on chromosome 2D that explains 23% of the variance. This QTL colocalized with a previously identified Cre3 locus. Novel QTL, QCcn.ha-2A, detected in the present study could be the possible unreported homeoloci to QCcn.ha-2D, QCcn.ha-2B.1 and QCcn.ha-2B.2. Six significant digenic epistatic interactions were also observed. In addition, 26 candidate genes were also identified including genes known for their involvement in PPNs (plant parasitic nematodes) resistance in different plant species. In-silico expression of putative candidate genes showed differential expression in roots during specific developmental stages. Results obtained in the present study are useful for wheat breeding to generate resistant genetic resources against H. avenae
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