3,396 research outputs found
Implicit surfaces with globally regularised and compactly supported basis functions
We consider the problem of constructing a function whose zero set is to represent a surface, given sample points with surface normal vectors. The contributions include a novel means of regularising multi-scale compactly supported basis functions that leads to the desirable properties previously only associated with fully supported bases, and show equivalence to a Gaussian process with modified covariance function. We also provide a regularisation framework for simpler and more direct treatment of surface normals, along with a corresponding generalisation of the representer theorem. We demonstrate the techniques on 3D problems of up to 14 million data points, as well as 4D time series data
Systemische Sklerose: Zielkriterien der Behandlung
Zusammenfassung: Die systemische Sklerose (SSc) ist eine Multisystemfibrose mit weltweitem Vorkommen und hoher Morbidität und Mortalität. Charakteristika der Erkrankung sind ausgedehnte Vaskulopathie, Entzßndung, Autoimmunität und Fibrose. Therapieerfolge der letzten Jahre beinhalten im Wesentlichen ein besseres Management von Organkomplikationen. Bis heute gibt es jedoch keine zugelassene spezifische Therapie, die das Fortschreiten der Erkrankung verhindern oder auch nur verlangsamen kann. Konventionelle DMARDs ("disease-modifying antirheumatic drugs") haben keinen substanziellen Einfluss auf den Erkrankungsverlauf und verlängern das Gesamtßberleben nicht. Aufgrund molekularbiologischer Studien und verschiedener Tiermodelle konnten in den letzten Jahren Schlßsselmolekßle der Pathogenese von Fibrose und Vaskulopathie in SSc identifiziert werden. Vor diesem Hintergrund mßssen nun Zielkriterien der Behandlung neu ßberdacht und definiert werden. In diesem Artikel werden mit Bezug auf pulmonal-arterielle Hypertonie, Lungenfibrose und Haut-/Systemfibrose aktuelle und kßnftige Therapiekonzepte, Ziele der Behandlung und Erfassung/Bewertung von Verlaufsparametern diskutier
Luminosity- and morphology-dependent clustering of galaxies
How does the clustering of galaxies depend on their inner properties like
morphological type and luminosity? We address this question in the mathematical
framework of marked point processes and clarify the notion of luminosity and
morphological segregation. A number of test quantities such as conditional
mark-weighted two-point correlation functions are introduced. These descriptors
allow for a scale-dependent analysis of luminosity and morphology segregation.
Moreover, they break the degeneracy between an inhomogeneous fractal point set
and actual present luminosity segregation. Using the Southern Sky Redshift
Survey~2 (da Costa et al. 1998, SSRS2) we find both luminosity and
morphological segregation at a high level of significance, confirming claims by
previous works using these data (Benoist et al. 1996, Willmer et al. 1998).
Specifically, the average luminosity and the fluctuations in the luminosity of
pairs of galaxies are enhanced out to separations of 15Mpc/h. On scales smaller
than 3Mpc/h the luminosities on galaxy pairs show a tight correlation. A
comparison with the random-field model indicates that galaxy luminosities
depend on the spatial distribution and galaxy-galaxy interactions. Early-type
galaxies are also more strongly correlated, indicating morphological
segregation. The galaxies in the PSCz catalog (Saunders et al. 2000) do not
show significant luminosity segregation. This again illustrates that mainly
early-type galaxies contribute to luminosity segregation. However, based on
several independent investigations we show that the observed luminosity
segregation can not be explained by the morphology-density relation alone.Comment: aastex, emulateapj5, 20 pages, 13 figures, several clarifying
comments added, ApJ accepte
Fingerprinting of chlorinated paraffins and their transformation products in plastic consumer products
Chlorinated paraffins (CPs) can be classified according to their length as short-chain (SC, C10-C13), medium-chain (MC, C14-C17) and long-chain (LC, C ⼠18) CPs. Technical CP-mixtures can contain a wide range of carbon- (C-, nC = 10-30) and chlorine- (Cl-, nCl = 3-19) homologues. CPs are high-production volume chemicals (>106 t/y). They are used as flame-retardants, plasticizers and coolant fluids. Due to the persistence, bioaccumulation, long-range environmental transport potential and adverse effects, SCCPs are regulated as persistent organic pollutants (POPs) by the Stockholm Convention. Transformation of CPs can lead to the formation of unsaturated compounds such as chlorinated mono- (CO), di- (CdiO) and tri-olefins (CtriO). Such transformation reactions can occur at different stages of CP manipulation providing characteristic C-/Cl-homologue distributions. All this results in unique patterns that collectively create a fingerprint, which can be distinguished from CP-containing samples. Therefore, CP-fingerprinting can develop into a promising tool for future source apportionment studies and with it, the reduction of environmental burden of CPs and hazards to humans. Herein, CP-containing plastics were studied to establish fingerprints and develop this method. We analyzed four household items by reverse-phase liquid-chromatography coupled with a mass spectrometer with an atmospheric pressure chemical ionization source and an Orbitrap mass analyzer (RP-LC-APCI-Orbitrap-MS) operated at a resolution of 120000 (FWHM at m/z 200). MS-data of different CP-, CO-, CdiO- and CtriO-homologues were efficiently processed with an R-based automatic mass spectra evaluation routine (RASER). From the 16720 ions searched for, up to 4300 ions per sample were assigned to 340 C-/Cl-homologues of CPs and their transformation products. Specific fingerprints were deduced from the C-/Cl-homologues distributions, the carbon- (nC) and chlorine- (nCl) numbers and saturation degree. These fingerprints were compared with the ones obtained by a GC-ECNI-Orbitrap-MS method
On the spherical-axial transition in supernova remnants
A new law of motion for supernova remnant (SNR) which introduces the quantity
of swept matter in the thin layer approximation is introduced. This new law of
motion is tested on 10 years observations of SN1993J. The introduction of an
exponential gradient in the surrounding medium allows to model an aspherical
expansion. A weakly asymmetric SNR, SN1006, and a strongly asymmetric SNR,
SN1987a, are modeled. In the case of SN1987a the three observed rings are
simulated.Comment: 19 figures and 14 pages Accepted for publication in Astrophysics &
Space Science in the year 201
The Reform of Employee Compensation in Chinaâs Industrial Enterprises
Although employee compensation reform in Chinese industrial sector has been discussed in the literature, the real changes in compensation system and pay practices have received insufficient attention and warrant further examination. This paper briefly reviews the pre- and post-reform compensation system, and reports the results of a survey of pay practices in the four major types of industrial enterprises in China. The research findings indicate that the type of enterprise ownership has little influence on general compensation practices, adoption of profit-sharing plans, and subsidy and allowance packages. In general, pay is linked more to individual performance and has become an important incentive to Chinese employees. However, differences are found across the enterprise types with regard to performance-related pay. Current pay practices are positively correlated to overall effectiveness of the enterprise
Privatization and State Capacity in Postcommunist Society
Economists have used cross-national regression analysis to argue that postcommunist economic failure is the result of inadequate adherence liberal economic policies. Sociologists have relied on case study data to show that postcommunist economic failure is the outcome of too close adherence to liberal policy recommendations, which has led to an erosion of state effectiveness, and thus produced poor economic performance. The present paper advances a version of this statist theory based on a quantitative analysis of mass privatization programs in the postcommunist world. We argue that rapid large-scale privatization creates severe supply and demand shocks for enterprises, thereby inducing firm failure. The resulting erosion of tax revenues leads to a fiscal crisis for the state, and severely weakens its capacity and bureaucratic character. This, in turn, reacts back on the enterprise sector, as the state can no longer support the institutions necessary for the effective functioning of a modern economy, thus resulting in deindustrialization. Using cross-national regression techniques we find that the implementation of mass privatization programs negatively impacts measures of economic growth, state capacity and the security of property rights.http://deepblue.lib.umich.edu/bitstream/2027.42/40192/3/wp806.pd
Using Abbreviated Injury Scale (AIS) codes to classify Computed Tomography (CT) features in the Marshall System
<p>Abstract</p> <p>Background</p> <p>The purpose of Abbreviated Injury Scale (AIS) is to code various types of Traumatic Brain Injuries (TBI) based on their anatomical location and severity. The Marshall CT Classification is used to identify those subgroups of brain injured patients at higher risk of deterioration or mortality. The purpose of this study is to determine whether and how AIS coding can be translated to the Marshall Classification</p> <p>Methods</p> <p>Initially, a Marshall Class was allocated to each AIS code through cross-tabulation. This was agreed upon through several discussion meetings with experts from both fields (clinicians and AIS coders). Furthermore, in order to make this translation possible, some necessary assumptions with regards to coding and classification of mass lesions and brain swelling were essential which were all approved and made explicit.</p> <p>Results</p> <p>The proposed method involves two stages: firstly to determine all possible Marshall Classes which a given patient can attract based on allocated AIS codes; via cross-tabulation and secondly to assign one Marshall Class to each patient through an algorithm.</p> <p>Conclusion</p> <p>This method can be easily programmed in computer softwares and it would enable future important TBI research programs using trauma registry data.</p
A Comparison of Major Arable Production Systems: An Agronomic, Environmental and Ecological Evaluation
One of the primary challenges of our time is develop sustainable farming systems that can feed the world with minimal environmental impact. Some studies argue that organic farming systems are best because these have minimal impact on the environment and are positive for biodiversity. Others argue that no-tillage systems are better because such systems save energy and preserve soil structure and quality. A third group argues that conventional farming systems are best because yield per hectare is highest. However, so far, systematic comparisons of major arable production systems are rare and often it is difficult to compare the advantages and disadvantages of farming systems in a systematic way due to differences in soil/site characteristics and management. Here we present data of the Swiss Farming Systems and Tillage Experiment (FAST), a long term experiment where the main European arable production systems (organic and conventional farming, reduced tillage and no tillage, each system with different cover crop treatments) are being compared using a factorial replicated design. A multidisciplinary team of researchers from various disciplines and organizations analysed this experiment.
We show the advantages and disadvantages of the various production systems and present data on plant yield, life cycle analysis, global warming potential, soil quality, plant root microbiomes and above and below ground biodiversity. Our results demonstrate that: i) plant yield was highest in the conventional systems, ii) soil biodiversity and above ground diversity tended to be higher in organic production systems, iii) soil erosion was lowest in the absence of tillage and in organic production systems, iv) the positive effects of cover crops were highest in organic production systems and increased with reduced land use intensity, v) the global warming potential of organic farming systems was lower compared to conventional systems, and vi) root and plant microbiome varied between the farming systems with the occurrence of indicator species that were specific for individual farming practices. In a next step we compared the results of this experiment with observations from a large farmers network (60 fields) in Switzerland (see abstract by BĂźchi et al.) where organic, conventional and conservation agriculture were compared. The results of our trial (e.g. yield and environmental performance of the different farming systems) were largely in agreement with those observed in the farmers network. Overall, our results indicate that no farming system is best and the choice of the âbestâ production system depends on economic, ecological and environmental priorities
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