241 research outputs found

    Fiscal Competition, Convergence and Agglomeration

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    This paper analyzes the impact of fiscal competition through infrastructure in a New Economic Geography framework. It is shown that regional competition leads to convergence if the trade costs are high but induces divergence if trade cost have fallen below a certain value. Moreover, fiscal competition yields an overprovision if the trade costs are sizable while it leads to underprovision if the regions are highly integrated. Finally, a trade-off between regional convergence and efficiency arises since the efficient distribution of regional infrastructure requires full agglomeration for sufficiently low trade costs.fiscal competition, infrastructure, agglomeration

    NTRC Plays a Crucial Role in Starch Metabolism, Redox Balance, and Tomato Fruit Growth

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    NADPH-thioredoxin reductase C (NTRC) forms a separate thiol-reduction cascade in plastids, combining both NADPHthioredoxin reductase and thioredoxin activities on a single polypeptide. While NTRC is an important regulator of photosynthetic processes in leaves, its function in heterotrophic tissues remains unclear. Here, we focus on the role of NTRC in developing tomato (Solanum lycopersicum) fruits representing heterotrophic storage organs important for agriculture and human diet. We used a fruit-specific promoter to decrease NTRC expression by RNA interference in developing tomato fruits by 60% to 80% compared to the wild type. This led to a decrease in fruit growth, resulting in smaller and lighter fully ripe fruits containing less dry matter and more water. In immature fruits, NTRC downregulation decreased transient starch accumulation, which led to a subsequent decrease in soluble sugars in ripe fruits. The inhibition of starch synthesis was associated with a decrease in the redox-activation state of ADP-Glc pyrophosphorylase and soluble starch synthase, which catalyze the first committed and final polymerizing steps, respectively, of starch biosynthesis. This was accompanied by a decrease in the level of ADP-Glc. NTRC downregulation also led to a strong increase in the reductive states of NAD(H) and NADP(H) redox systems. Metabolite profiling of NTRC-RNA interference lines revealed increased organic and amino acid levels, but reduced sugar levels, implying that NTRC regulates the osmotic balance of developing fruits. These results indicate that NTRC acts as a central hub in regulating carbon metabolism and redox balance in heterotrophic tomato fruits, affecting fruit development as well as final fruit size and qualit

    Vision and Eye Care in Older Adults

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    https://deepblue.lib.umich.edu/bitstream/2027.42/145685/1/NPHA_Vision-Report_FINAL-082718.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/145685/2/12_September-2018-Vision-Report-Qs_083018.pd

    Characterization and Compensation of Network-Level Anomalies in Mixed-Signal Neuromorphic Modeling Platforms

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    Advancing the size and complexity of neural network models leads to an ever increasing demand for computational resources for their simulation. Neuromorphic devices offer a number of advantages over conventional computing architectures, such as high emulation speed or low power consumption, but this usually comes at the price of reduced configurability and precision. In this article, we investigate the consequences of several such factors that are common to neuromorphic devices, more specifically limited hardware resources, limited parameter configurability and parameter variations. Our final aim is to provide an array of methods for coping with such inevitable distortion mechanisms. As a platform for testing our proposed strategies, we use an executable system specification (ESS) of the BrainScaleS neuromorphic system, which has been designed as a universal emulation back-end for neuroscientific modeling. We address the most essential limitations of this device in detail and study their effects on three prototypical benchmark network models within a well-defined, systematic workflow. For each network model, we start by defining quantifiable functionality measures by which we then assess the effects of typical hardware-specific distortion mechanisms, both in idealized software simulations and on the ESS. For those effects that cause unacceptable deviations from the original network dynamics, we suggest generic compensation mechanisms and demonstrate their effectiveness. Both the suggested workflow and the investigated compensation mechanisms are largely back-end independent and do not require additional hardware configurability beyond the one required to emulate the benchmark networks in the first place. We hereby provide a generic methodological environment for configurable neuromorphic devices that are targeted at emulating large-scale, functional neural networks

    Placenta Percreta Presents with Neoangiogenesis of Arteries with Von Willebrand Factor-Negative Endothelium

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    In placenta percreta cases, large vessels are present on the precrete surface area. As these vessels are not found in normal placentation, we examined their histological structure for features that might explain the pathogenesis of neoangiogenesis induced by placenta accreta spectrum disorders (PAS). In two patients with placenta percreta (FIGO grade 3a) of the anterior uterine wall, one strikingly large vessel of 2 cm length was excised. The samples were formalin fixed and paraffin-embedded. Gomori trichrome staining was used to evaluate the muscular layers and Weigert-Van Gieson staining for elastic fibers. Immunohistochemical staining of the vessel endothelium was performed for Von Willebrand factor (VWF), platelet endothelial cell adhesion molecule (CD31), Ephrin B2, and EPH receptor B4. The structure of the vessel walls appeared artery-like. The vessel of patient one further exhibited an unorderly muscular layer and a lack of elastic laminae, whereas these features appeared normal in the vessel of the other patient. The endothelium of both vessels stained VWF-negative and CD31-positive. In conclusion, this study showed VWF-negative vessel endothelia of epiplacental arteries in placenta accreta spectrum. VWF is known to regulate artery formation, as the absence of VWF has been shown to cause enhanced vascularization. Therefore, we suppose that PAS provokes increased vascularization through suppression of VWF. This process might be associated with the immature vessel architecture as found in one of the vessels and Ephrin B2 and EPH receptor B4 negativity of both artery-like vessels. The underlying pathomechanism needs to be evaluated in a greater set of patients

    Case study of a humidity layer above Arctic stratocumulus and potential turbulent coupling with the cloud top

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    Specific humidity inversions (SHIs) above low-level cloud layers have been frequently observed in the Arctic. The formation of these SHIs is usually associated with large-scale advection of humid air masses. However, the potential coupling of SHIs with cloud layers by turbulent processes is not fully understood. In this study, we analyze a 3 d period of a persistent layer of increased specific humidity above a stratocumulus cloud observed during an Arctic field campaign in June 2017. The tethered balloon system BELUGA (Balloon-bornE moduLar Utility for profilinG the lower Atmosphere) recorded vertical profile data of meteorological, turbulence, and radiation parameters in the atmospheric boundary layer. An in-depth discussion of the problems associated with humidity measurements in cloudy environments leads to the conclusion that the observed SHIs do not result from measurement artifacts. We analyze two different scenarios for the SHI in relation to the cloud top capped by a temperature inversion: (i) the SHI coincides with the cloud top, and (ii) the SHI is vertically separated from the lowered cloud top. In the first case, the SHI and the cloud layer are coupled by turbulence that extends over the cloud top and connects the two layers by turbulent mixing. Several profiles reveal downward virtual sensible and latent heat fluxes at the cloud top, indicating entrainment of humid air supplied by the SHI into the cloud layer. For the second case, a downward moisture transport at the base of the SHI and an upward moisture flux at the cloud top is observed. Therefore, the area between the cloud top and SHI is supplied with moisture from both sides. Finally, large-eddy simulations (LESs) complement the observations by modeling a case of the first scenario. The simulations reproduce the observed downward turbulent fluxes of heat and moisture at the cloud top. The LES realizations suggest that in the presence of a SHI, the cloud layer remains thicker and the temperature inversion height is elevated

    Anisotropy of Growth of the Close-Packed Surfaces of Silver

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    The growth morphology of clean silver exhibits a profound anisotropy: The growing surface of Ag(111) is typically very rough while that of Ag(100) is smooth and flat. This serious and important difference is unexpected, not understood, and hitherto not observed for any other metal. Using density functional theory calculations of self-diffusion on flat and stepped Ag(100) we find, for example, that at flat regions a hopping mechanism is favored, while across step edges diffusion proceeds by an exchange process. The calculated microscopic parameters explain the experimentally reported growth properties.Comment: RevTeX, 4 pages, 3 figures in uufiles form, to appear in Phys. Rev. Let

    Efficacy and safety of an intravenous monoclonal anti-HBs in chronic hepatitis B patients

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    Background Aims: In this study the safety and efficacy of a monoclonal anti-HBs, Tuvirumab (Mab), were investigated. Tuvirumab is a human monoclonal antibody recognizing the stable 'a'-determinant of the HBsAg. Methods: We included ten chronic hepatitis B patients: four received monotherapy, and six combination therapy with interferon alpha 2b. Results: Because the development of insoluble [HBsAg-HBsAb] complexes led to adverse events, the Mab dose had to be reduced in seven patients. In nine patients treatment was stopped prematurely because of lack of efficacy, i.e. neutralization of HBsAg in serum. However, temporary HBsAg levels were reduced by at least 50% in all patients; in three patients receiving combination therapy, background levels of HBsAg in serum were reached. A loss of serum HBV-DNA was seen in three patients in the combination group, followed by HBeAg seroconversion in two patients. Conclusions: We conclude that Mab was not effective in achieving primary efficacy as assessed by neutralization of circulating HBsAg. Whether a combination of Mab with an antiviral agent that reduces the HBsAg load - and therefore minimizes the risk of adverse events - may result in clinical efficacy should be investigated

    A comprehensive in situ and remote sensing data set from the Arctic CLoud Observations Using airborne measurements during polar Day (ACLOUD) campaign

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    The Arctic CLoud Observations Using airborne measurements during polar Day (ACLOUD) campaign was carried out north-west of Svalbard (Norway) between 23 May and 6 June 2017. The objective of ACLOUD was to study Arctic boundary layer and mid-level clouds and their role in Arctic amplification. Two research aircraft (Polar 5 and 6) jointly performed 22 research flights over the transition zone between open ocean and closed sea ice. Both aircraft were equipped with identical instrumentation for measurements of basic meteorological parameters, as well as for turbulent and radiative energy fluxes. In addition, on Polar 5 active and passive remote sensing instruments were installed, while Polar 6 operated in situ instruments to characterize cloud and aerosol particles as well as trace gases. A detailed overview of the specifications, data processing, and data quality is provided here. It is shown that the scientific analysis of the ACLOUD data benefits from the coordinated operation of both aircraft. By combining the cloud remote sensing techniques operated on Polar 5, the synergy of multi-instrument cloud retrieval is illustrated. The remote sensing methods were validated using truly collocated in situ and remote sensing observations. The data of identical instruments operated on both aircraft were merged to extend the spatial coverage of mean atmospheric quantities and turbulent and radiative flux measurement. Therefore, the data set of the ACLOUD campaign provides comprehensive in situ and remote sensing observations characterizing the cloudy Arctic atmosphere. All processed, calibrated, and validated data are published in the World Data Center PANGAEA as instrument-separated data subsets (Ehrlich et al., 2019b, https://doi.org/10.1594/PANGAEA.902603)
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