164 research outputs found
Consequences of Data Error in Aggregate Indicators: Evidence from the Human Development Index
This paper examines the consequences of data error in data series used to construct aggregate indicators. Using the most popular indicator of country level economic development, the Human Development Index (HDI), we identify three separate sources of data error. We propose a simple statistical framework to investigate how data error may bias rank assignments and identify two striking consequences for the HDI. First, using the cutoff values used by the United Nations to assign a country as âlowâ, âmediumâ, or âhighâ developed, we find that currently up to 45% of developing countries are misclassified. Moreover, by replicating prior development/macroeconomic studies, we find that key estimated parameters such as Gini coefficients and speed of convergence measures vary by up to 100% due to data error.measurement error, international comparative statistics
Considering the shareholder perspective: value-based management systems and stock market performance
We empirically study the use of value-based management systems in listed German firms and examine implications for firms' stock market performance. Using a novel, hand-collected data set covering 1,083 firm years from 2002 to 2008, we find that value-based management systems become increasingly common. Specifically, in 2008 42% of our sample firms have implemented such a system. In the empirical analysis, we find that firms that implement value-based management systems earn statistically significant and economically substantial abnormal stock market returns measured within a two-year adoption phase. These excess returns are not jeopardized by poor post-adoption returns. In the analysis, we carefully control for risk and account for endogeneity concerns. Overall, our findings support the view that shareholders consider the adoption of a value-based management system as a credible signal that management will focus on shareholder interests and that such systems actually increase shareholder value. --value-based management,corporate governance,econometric analysis,Germany
Trends in the concentration and distribution of health care expenditures in the US, 2001-2018
Importance: The concentration of health care expenditures has important implications for managing risk pools, drug benefit design, and care management. Objective: To examine trends in the concentration of health care spending in different population groups and expenditure categories in the US between 2001 and 2018. Design, Setting, and Participants: This study is a cross-sectional analysis of Medical Expenditure Panel Surveys (MEPS) collected between 2001 and 2018. The MEPS is a household survey of medical expenditures weighted to represent national estimates in the US. Respondents were a nationally representative sample of the US civilian noninstitutionalized population. Data analysis was performed from December 2020 to February 2021. Main Outcomes and Measures: The main outcome is the concentration of health care expenditures as measured by the cumulative percentage of health expenditure vs percentage of ranked population. This study reports trends in the distribution of populations across 4 concentration curve parameters: top 50% expenditure (high spenders), next 49% expenditure (medium spenders), next 1% expenditure (low spenders), and nonspenders. Results: The mean sample size of the MEPS surveys used in the analysis was 34539 individuals, and the sample size varied between 30461 and 39165 individuals over the years studied. On the basis of data from 30461 MEPS respondents (15867 women [52.1%]; mean [SD] age, 38.9 [24.0] years) in 2018, the top 4.6% (95% CI, 4.3%-4.9%) of the US population by spending accounted for 50% of health care expenditures. Although this fraction varied across population groups or expenditure categories, it remained remarkably stable over time with one exception: the concentration of spending on prescription drugs. In 2001, one-half of all expenditures on prescription drugs were concentrated in 6.0% (95% CI, 5.6%-6.4%) of the US population, but by 2018, this proportion had decreased to 2.3% (95% CI, 2.1%-2.5%). This change does not appear to be associated with a change in the overall share of prescription drug expenses, which increased by only a small amount, from 20.4% in 2001 to 24.8% in 2018. Conclusions and Relevance: The overall concentration of health care expenditures remained stable between 2001 and 2018, but these findings suggest that there has been a sharp increase in the concentration of spending on prescription drugs in the US. This coincides with the genericization of many primary care drugs, along with a shift in focus of the biopharmaceutical industry toward high-cost specialty drugs targeted at smaller populations. If this trend continues, it will have implications for the minimum scale of risk-bearing and drug management needed to operate efficiently, as well as the optimal cost-sharing features of insurance products.
Classification, Detection and Consequences of Data Error: Evidence from the Human Development Index
We measure and examine data error in health, education and income statistics used to construct the Human Development Index. We identify three sources of data error which are due to data updating; formula revisions; and thresholds to classify a countryâs development status. We propose a simple statistical framework to calculate country specific measures of data uncertainty and investigate how data error biases rank assignments. We find that up to 34% of countries are misclassified and, by replicating prior studies, we show that key estimated parameters vary by up to 100% due to data error
RootJS: Node.js Bindings for ROOT 6
We present rootJS, an interface making it possible to seamlessly integrate
ROOT 6 into applications written for Node.js, the JavaScript runtime platform
increasingly commonly used to create high-performance Web applications. ROOT
features can be called both directly from Node.js code and by JIT-compiling C++
macros. All rootJS methods are invoked asynchronously and support callback
functions, allowing non-blocking operation of Node.js applications using them.
Last but not least, our bindings have been designed to platform-independent and
should therefore work on all systems supporting both ROOT 6 and Node.js.
Thanks to rootJS it is now possible to create ROOT-aware Web applications
taking full advantage of the high performance and extensive capabilities of
Node.js. Examples include platforms for the quality assurance of acquired,
reconstructed or simulated data, book-keeping and e-log systems, and even Web
browser-based data visualisation and analysis.Comment: 7 pages, 1 figure. To appear in the Proceedings of the 22nd
International Conference on Computing in High Energy and Nuclear Physics
(CHEP 2016
Structure turnover times of grassland soils under different moisture regimes
Soil structure is a dynamic property of soils, which refers to temporal changes in the spatial arrangement of pores, organic matter, and minerals. Its turnover, i.e. the irreversible redistribution of soil constituents, determines essential soil functions including carbon storage. Structure turnover times and its response to biotic versus abiotic drivers have never been quantified directly under natural conditions. We used a novel combination of structure labelling with inert garnet particles and X-ray Computed Tomography to determine structure turnover times of two grassland topsoils with either access or exclusion of roots and fauna > 30 mu m. Both, abiotic and biotic factors developed soil structure at a site-specific rate towards a dynamic equilibrium, at which bulk properties remain constant because creation and destruction of structural properties are in balance. Its turnover, however, was mainly determined by macrofaunal activity which varied with environmental conditions. Under dry conditions less favorable for bioturbation, the extrapolated structure turnover time was 33 +/- 3 years, while being 16 +/- 1 years under moist conditions. Previous studies on organic matter turnover determined in the vicinity of the experimental site showed similar turnover times for particulate organic matter. The similar turnover times suggest that the accessibility of particulate organic matter to decomposers is closely linked to structure turnover, thus highlighting the intimate nexus between structure evolution and carbon persistence in soil
Polymer brush collapse under shear flow
Shear responsive surfaces offer potential advances in a number of
applications. Surface functionalisation using polymer brushes is one route to
such properties, particularly in the case of entangled polymers. We report on
neutron reflectometry measurements of polymer brushes in entangled polymer
solutions performed under controlled shear, as well as coarse-grained computer
simulations corresponding to these interfaces. Here we show a reversible and
reproducible collapse of the brushes, increasing with the shear rate. Using two
brushes of greatly different chain lengths and grafting densities, we
demonstrate that the dynamics responsible for the structural change of the
brush are governed by the free chains in solution rather than the brush itself,
within the range of parameters examined. The phenomenon of the brush collapse
could find applications in the tailoring of nanosensors, and as a way to
dynamically control surface friction and adhesion
Gestaltung von In-Car Multi-Device Cross-Platform Umgebungen
Die Gestaltung von graphischen BedienoberflĂ€chen fĂŒr Applikationen in Umgebungen mit mehreren GerĂ€ten unterschiedlicher Hersteller wird immer bedeutender â auch in der Automobilbranche. Um dieser Herausforderung zu begegnen, muss verstanden werden, wie Design-Entscheidungen fĂŒr solche Applikationen getroffen werden. Als Vorstudie einer Untersuchung dieser Thematik wurden neun User Experience Designer befragt. Der Fokus liegt auf Anwendungen fĂŒr in-car Entertainment- und Komfortfunktionen auf integrierten und mitgebrachten GerĂ€ten. Konkret erkannt als die gröĂten Probleme fĂŒr ĂŒbergreifende Konzepte sind: Das Aufeinandertreffen unterschiedlicher Konsistenzen durch plattformspezifische Gestaltungsparadigmen und PrĂ€missen, das Fehlen von spezifischen Prozessen, Methoden und Werkzeugen um Zielkonflikte aufzulösen. Das Kernproblem ist das Fehlen einer wissenschaftlich ermittelten Grundlage, wie sich User Experience in MehrgerĂ€teumgebungen unterschiedlicher Hersteller
verhÀlt
A micro-CT-based method for quantitative brain lesion characterization and electrode localization
Lesion verification and quantification is traditionally done via histological examination of sectioned brains, a time-consuming process that relies heavily on manual estimation. Such methods are particularly problematic in posterior cortical regions (e.g. visual cortex), where sectioning leads to significant damage and distortion of tissue. Even more challenging is the post hoc localization of micro-electrodes, which relies on the same techniques, suffers from similar drawbacks and requires even higher precision. Here, we propose a new, simple method for quantitative lesion characterization and electrode localization that is less labor-intensive and yields more detailed results than conventional methods. We leverage staining techniques standard in electron microscopy with the use of commodity micro-CT imaging. We stain whole rat and zebra finch brains in osmium tetroxide, embed these in resin and scan entire brains in a micro-CT machine. The scans result in 3D reconstructions of the brains with section thickness dependent on sample size (12â15 and 5â6 microns for rat and zebra finch respectively) that can be segmented manually or automatically. Because the method captures the entire intact brain volume, comparisons within and across studies are more tractable, and the extent of lesions and electrodes may be studied with higher accuracy than with current methods
The bioaccessibility and bioavailability of subsoil phosphorus from P-33-labeled hydroxyapatite
Phosphorus (P) is an essential but often limiting macronutrient in ecosystems. In soil, free phosphorus is rapidly immobilized by sorption onto hydrous oxides or minerals containing Fe, Mn and Al. Therefore plants have the need to increase the availability of P from other sources e.g. solubilizing P from mineral apatite. Apatite can be found in mineral and biological forms, such as residues from bones and dentin, in soil. This Ca-phosphate mineral occurs in trace amounts in practically all metamorphic and igneous rocks and is often found as small mineral inclusions associated to weathering-resistant silicate minerals. Yet, there is not much information on the bioavailability of P from mineral apatite. Numerous papers have been published on hydroxyapatite synthesis, mostly focusing on its use as a bioceramic for biomedical applications that often differ in their physic-chemical properties from mineral apatite. In framework of the DFG-SPP 1685 on ecosystem nutrients the aim of this work was to implement a chemical synthesis for P-33-labeled hydroxyapatite (Ca/P ratio = 1.67) in order to get more information on the bioaccessibility and bioavailability of subsoil P from minerals. A wet-chemical synthesis based on Wang et al. (2010), has been modified and extended, to create a procedure that allows the fast preparation (ca. 30 h) of hydroxyl-apatite labeled with P-33. The products were analyzed with IR-RAMAN and XRD. The reactions were performed under different reaction temperatures which resulted in four forms of hydroxyapatite with different degrees of crystallinity (amorphous high crystalline). Solubility tests were performed with all forms to investigate their pH-dependency, stating that the amorphous and high crystalline forms behave similar but differ from the intermediate forms. Rhizotrone experiments (60 days) will be performed using summer wheat as model organisms and the amorphous apatite form as point sources in soil. Two different subsoils (P-deficient/non-deficient) with two different water scenarios will be used to investigate the differences in root growth and the effects on the bioaccessibility and âavailability of P from apatite. Radioactive imaging will be used to get information on the time that the roots need to grow to the apatite source, the amount that is taken up into the plant and to locate the areas of P-storage. High resolution pictures will be taken to investigate the growth of the root system for modeling purposes
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