julilili42/papers huggingface dataset:
Spectral modeling of gaseous metal disks around DAZ white dwarfs
2009-06-01

We report on our attempt for the first non-LTE modeling of gaseous metal disks around single DAZ white dwarfs recently discovered by Gaensicke et al. and thought to originate from a disrupted asteroid. We assume a Keplerian rotating viscous disk ring composed of calcium and hydrogen and compute the detailed vertical structure and emergent spectrum. We find that the observed infrared CaII emission triplet can be modeled with a hydrogen-deficient gas ring located at R=1.2 R_sun, inside of the tidal disruption radius, with Teff about 6000 K and a low surface mass density of about 0.3 g/cm**2. A disk having this density and reaching from the central white dwarf out to R=1.2 R_sun would have a total mass of 7 10**21 g, corresponding to an asteroid with about 160 km diameter.
Isometric registration of ambiguous and partial data
2009-06-01

This paper introduces a new shape matching algorithm for computing correspondences between 3D surfaces that have undergone (approximately) isometric deformations. The new approach makes two main contributions: First, the algorithm is, unlike previous work, robust to “topological noise” such as large holes or “false connections”, which is both observed frequently in real-world scanner data. Second, our algorithm samples the space of feasible solutions such that uncertainty in matching can be detected explicitly. We employ a novel randomized feature matching algorithm in order to find robust subsets of geodesics to verify isometric consistency. The paper shows shape matching results for real world and synthetic data sets that could not be handled using previous deformable matching algorithms.
Authentication and secrecy codes for equiprobable source probability distributions
2009-06-01

We give new combinatorial constructions for codes providing authentication\\nand secrecy for equiprobable source probability distributions. In particular,\\nwe construct an infinite class of optimal authentication codes which are\\nmultiple-fold secure against spoofing and simultaneously achieve perfect\\nsecrecy. Several further new optimal codes satisfying these properties will\\nalso be constructed and presented in general tables. Almost all of these appear\\nto be the first authentication codes with these properties.\\n
(F)UV spectroscopy of the hybrid PG1159-type central stars of the planetary nebulae NGC 7094 and Abell43
2009-06-01

Hydrogen-deficient post-AGB stars have experienced a late helium-shell flash that mixes the hydrogen-rich envelope and the helium-rich intershell (between hydrogen- and helium-burning shell). The amount of hydrogen remaining in the stellar envelope depends on the particular moment when this late thermal pulse occurs. Previous spectral analyses of hydrogen-deficient post-AGB stars, namely PG 1159-035 and the central stars of the planetary nebulae (CSPN) K 1-16, NGC 7094, and Abell 78, surprisingly revealed strong iron deficiencies of up to 1 dex. A possible explanation may be neutron captures due to an efficient s-process on the AGB that transformed iron into heavier elements. An increased abundance of these would be a strong indication for this scenario. Since reliable atomic data for highly ionized species heavier than iron is only available for cobalt and nickel, we can presently determine only the nickel abundance. We performed a detailed spectral analysis by means of NLTE model-atmosphere techniques based on high-resolution UV observations of the two PG 1159-type CSPN of NGC 7094 and Abell 43 which are spectroscopic twins, i.e., they exhibit very similar spectra. We confirmed a strong iron-deficiency of at least one dex in both stars. The search for nickel lines in their UV spectra was entirely negative. We find that both stars are even nickel deficient by about one dex.
Should photodynamic diagnosis be standard practice for bladder cancer?
2009-06-01

Bladder cancer (BC) is a frequently common disease with the highest lifetime treatment costs per patient of all cancers [1]. With an estimated 70,980 new diagnoses of BC and approximately 14,330 BC...
Dynamic masses for the close PG1159 binary SDSSJ212531.92-010745.9
2009-06-01

The evolutionary scenarios which are commonly accepted for PG 1159 stars are mainly based on numerical simulations. These stellar evolution scenarios have to be tested and calibrated with real objects with known stellar parameters. One of the most crucial but also quite uncertain parameters is the stellar mass. PG 1159 stars have masses between 0.5 and 0.8 solar masses, as derived from asteroseismic and spectroscopic determinations. Such mass determinations are, however, themselves model-dependent. Moreover, asteroseismologically and spectroscopically determined masses deviate systematically for PG1159 stars by up to 10 %. SDSSJ212531.92-010745.9 is the first known PG1159 star in a close binary with a late main sequence companion allowing a dynamical mass determination. The system shows flux variations with a peak-to-peak amplitude of about 0.7 mag and a period of about 6.96 h. In August 2007, 13 spectra of SDSS J212531.92-010745.9 covering the full orbital phase range were taken at the TWIN 3.5m telescope at the Calar Alto Observatory (Almería, Spain). These confirm the typical PG1159 features seen in the SDSS discovery spectrum, together with the Balmer series of hydrogen in emission (plus other emission lines), interpreted as signature of the companion's irradiated side. A radial velocity curve was obtained for both components. Using co-added radial-velocity-corrected spectra, the spectral analysis of the PG 1159 star is being refined. The system's lightcurve, obtained during three seasons of photometry with the Göttingen 50 cm and Tübingen 80 cm telescopes, was fitted with both the NIGHTFALL and PHOEBE binary simulation programs. An accurate mass determination of the PG 1159 component from the radial velocity measurements requires to first derive the inclination, which requires light curve modelling and yields further constraints on radii, effective temperature and separation of the system's components. From the analysis of all data available so far, we present the possible mass range for the PG1159 component of SDSSJ212531.92-010745.9.
Incorporating molecular flexibility into three-dimensional structural kernels
2009-06-01

The molecular conformation has an important impact on the biological activity of a ligand. To include the information of the conformational space into a similarity measure, it is necessary to perform a time-consuming conformational sampling of the structures. We approached this problem by introducing a new method to incorporate the geometry in a structured similarity measure. The basic concept is to breakdown the complete conformational space of a structure into local conformations of neighbour atoms with respect to core atoms. These local conformations are the trajectories of the second and third degree neighbours and arise from rotatable bonds. The parameters of the trajectories can be used to expand the physicochemical descriptors of structured similarity measures. We extended the optimal assignment kernel with our procedure and used the resulting pseudo-kernel in support vector machines. To assess the influence of our extension, we compared the QSAR results of the original and extended version of the pseudo-kernel on 8 benchmark data sets. The incorporation of the local conformation information significantly improves the model quality on 5 out of 8 data sets. from 4th German Conference on Chemoinformatics Goslar, Germany. 9–11 November 2008
24μm excesses of hot WDs – Evidence of dust disks?
2009-06-01

Spitzer Space Telescope observations of the Helix Nebula's hot (Teff ≈ 110 000 K) central star revealed mid-IR excess emission consistent with a continuum emission from a dust disk located at 35-150 AU from the central white dwarf (WD), and the dust is most likely produced by collisions among Kuiper Belt-like objects (Su et al. 2007). To determine how common such dust disks are, we have carried out a Spitzer 24 μm survey of 72 hot WDs, and detected at least 7 WDs that exhibit clear IR excess, all of them still surrounded by planetary nebulae (PNe). Inspired by the prevalence of PN environment for hot WDs showing IR excesses, we have surveyed the Spitzer archive for more central stars of PN (CSPNs) with IR excesses; the search yields four cases in which CSPNs show excesses in 3.6-8.0 μm, and one additional case of 24 μm excess. We present the results of these two searches for dust-disk candidates, and discuss scenarios other than KBO collisions that need to be considered in explaining the observed near and/or mid-IR excess emission. These scenarios include unresolved companions, binary post-AGB evolution, and unresolved compact nebulosity. We describe planned follow-up observations aiming to help us distinguish between different origins of observed IR excesses.
Collaborative Web Service Interface Design on the Web 2.0
2009-06-01

In the service oriented architecture, Web services are the standard means of providing functionality to a remote partner. The interfaces of these Web Services are defined in the Web Services Description Language (WSDL). If two or more partners are involved in the development of a Web Service, a need to collaboratively edit service interface definitions can arise in order to increase productivity and to prevent ambiguities. In this paper, we investigate the process of collaborative interface design and present a Web-based, collaborative WSDL development system, which can be integrated with a collaborative workflow development system.
Sex-specific differences in foot morphology: A follow-up study
2009-06-01

Knowledge of sexual dimorphism in foot morphology is important for forensic and psychological research (Fessler et al. 2005, Agnihotri et al. 2007), as well as the manufacturing of shoes, and athle...
Controlling the optical properties of single molecules by optical confinement in a tunable microcavity
2009-06-01

Optical microcavities are structures which confine light to a small region in the range of one wavelength. The radiation of a quantum emitter is coupled to cavity resonances which leads to an optical confinement of the broadband fluorescence. A practical design for this single-mode microcavity is formed by two silver mirrors enclosing a transparent dielectric medium with single quantum emitters. Steiner et al. have shown that the fluorescence spectra and decay lifetimes of single molecules in this Fabry-Perot type microcavity are strongly dependent on the resonator length.
Preliminary XCOV26 results for EC14012-1446
2009-06-01

EC14012-1446 is a hydrogen atmosphere (DA) white dwarf pulsator. Its rich pulsation spectrum displays a range of excited modes with complex multiplet structure, in addition to numerous combination frequencies. In April 2008, EC14012-1446 was the primary target of XCOV26. We obtained over 300 hrs of nearly continuous high speed photometry with the goal of using the nonlinear pulse shapes to empirically determine the parameters of the convection zone. The Fourier transform (FT) of the light curve contains power between 1000 to 4000 μHz, with the dominant peak at 1234 μHz. We find 13 independent frequencies distributed in 8 modes, as well as a myriad of combination frequencies. In the following, we present preliminary results and lay the groundwork for future investigation leading to light curve fitting of EC14012-1446.
An extension of the pharmacophore kernel using radial atomtype fingerprints
2009-06-01

The prediction of the biological activity of a chemical compound is a challenging task in Computational Chemistry and was restricted to vectorial representations of the molecular graph for decades. Kernel functions are positive semidefinite similarity measures that can be defined on arbitrary structured data. This class of similarity functions can be used in kernel-based machine learning algorithms. Interestingly, many graph kernel approaches from Computer Science share properties of traditional similarity measures for chemical compounds, like molecular fingerprints based on paths, cycles and subgraphs.
Two-step hierarchical assignments on molecular graphs
2009-06-01

Measures for the similarity of molecules are of interest for several in silico based tasks like virtual screening or de novo structure design. The Optimal Assignment Kernel (OAK) [1] is a successful similarity measure, although it is not a valid kernel, since the function is not positive definite [2]. Careful investigations of the assignment on the atom level disclose that the optimal assignment with the Hungarian algorithm may result in topological errors. These errors are mappings of atoms from chemical substructures like ring systems to atoms of the other molecule, which belong to different substructures or even can be scattered among the molecule. This yields an overall higher similarity score but is problematic from a chemical point of view. To avoid these topological errors we developed a two-step hierarchical assignment method and compared it with the OAK.
Geometric $\\pi$ Josephson Junction: Current-Phase Relations and Critical Current
2009-06-01

Josephson junctions with an intrinsic phase shift of pi, so-called pi\\nJosephson junctions, can be realized by a weak link of a d-wave superconductor\\nwith an appropriate boundary geometry. A model for the pairing potential of an\\naccording weak link is introduced which allows for the calculation of the\\ninfluence of geometric parameters and temperature. From this model,\\ncurrent-phase relations and the critical current of the device are derived. The\\nrange of validity of the model is determined by comparison with selfconsistent\\nsolutions.\\n
On psychodynamics of personal value-judgements – Nietzsche's theory of resentment and its reception by Karl Jaspers and Kurt Schneider
2009-06-01

Abstract: A hundred years ago when Karl Jaspers was introducing psychological understanding to psychiatry the founder of the school of Heidelberg spoke of Friedrich Nietzsche as one of the “greatest” psychologists. Especially his theory of resentment with its core thesis unconscious prejudices were influencing our behaviour was able to illuminate the complex structure of human will. Taking into account this horizon of psychiatric history of ideas the presentation wants to persecute the following three questions: 1) Why the postulate which Nietzsche was giving on cultural prejudices of our thoughts, feelings and acts was so provocative so that many of the classical thinkers of psychological understanding were taking it up according to the needs of their disciplines sociology, psychology, psychiatry and philosophy? 2) What were the results of this inspiring theory which could be especially seen in the works of Karl Jaspers and Kurt Schneider? In other words: What were the aspects in which they agreed in their reception of Nietzsche and what were the points in which the two psychiatrists of the school of Heidelberg differed in the way they took the theory of resentment into account for their psychological understanding? 3) What could be the actual significance of the historical fact that Nietzsche and in his footsteps Max Weber were taking deep influence on psychiatric thinking around 1900?
Colour in action: evidence for a redundancy signal effect when driving motor responses by combined colour and spatial cues
2009-06-01

Several studies have demonstrated that either chromatic or spatial information can guide motor behaviour, but so far interactions between these two visual features are little understood. Here we addressed this issue by measuring reaction times (RT) for pointing hand movements which were instructed by either cues for spatial (thought to be predominantly processed in the dorsal visual stream), colour (thought to be predominantly processed in the ventral visual stream) or redundant (combination of colour and spatial information) conditions. While faster responses were found for spatial than for colour cues, most importantly, the shortest RTs were measured for the combined cues (redundancy signal effect, RSE). The data are inconsistent with the predictions of the race model which assumes parallel and independent input from the two streams to the motor system. Instead, the data are better explained by the coactivation model, which proposes combined sensory information from the different stimuli and detection process from the sum of the signals. Here, the redundancy signal effect results from the combination of colour and spatial information. The results provide behavioural evidence for an integration of colour and spatial cues when guiding hand movements.
THE EFFECTS OF 8 WK INTENSIVE JUDO TRAINING ON THE HUMORAL IMMUNE SYSTEM IN JUDO FIGHTERS
2009-06-01

&amp;lt;p&amp;gt;The influence of intensive Judo training on serum immunoglobulins IgG, IgM, and IgA was studied in 24 Judo fighters. Subjects were assigned to an exercise training group (EXE; n=12) and non-exercise control group (Con; n=12). Subjects in EXE group participated in exercise sessions 4 days a week for 8 wk. Serum samples were collected before, immediately and 1wk after study period. The IgG levels were significantly increased immediately after exercise training (p=0.001) in EXE compared to Con. However, IgM and IgA concentrations showed significant decrease immediately after exercise in EXE (p=0.001). The concentrations of all immunoglobulins had returned to baseline by 1wk of recovery. In conclusion the increased IgG levels are possibly due to isotype switching or a secondary antibody responses that could be considered as enhancement in immune system function. However, chronic suppression of immuniglobulins IgM and IgA may be mediated by hormonal changes associated with exhausting exercise.&amp;lt;/p&amp;gt;
Novel Lead Structures for p38 MAP Kinase via FieldScreen Virtual Screening
2009-06-02

p38 MAP kinase has received considerable interest in the pharmaceutical industry and remains a valid and interesting target for the treatment of inflammation. To discover novel p38 inhibitors, we applied the ligand-based virtual screening technique, FieldScreen, to 1.2 million commercially available compounds. Fifty-eight diverse compounds were selected for biological analysis, using molecular field similarity to known inhibitors, while explicitly removing any structure that shared a scaffold with previously reported p38 inhibitors. Of these, 11 (19%) showed >or=20% inhibition of p38 at 10 microM. We chose to prepare analogues of two distinct chemical series resulting in a potential lead compound with pIC(50) of 6.4. Modeling of SAR using FieldAlign, a ligand alignment protocol, was used to rationalize the SAR of the series of thiadiazole based inhibitors.
Enhancement of Planning Ability by Transcranial Direct Current Stimulation
2009-06-03

The functional neuroanatomy of executive function critically involves the dorsolateral prefrontal cortex. Transcranial direct current stimulation (tDCS) has been established as a noninvasive tool for transient modulation of cortical function. Here, we examined the effects of tDCS of the left dorsolateral prefrontal cortex on planning function by using the Tower of London task to evaluate performance during and after anodal, cathodal (1 mA, 15 min), and sham tDCS in 24 healthy volunteers. The key finding was a double dissociation of polarity and training phase: improved performance was found with cathodal tDCS applied during acquisition and early consolidation, when preceding anodal tDCS, but not in the later training session. In contrast, anodal tDCS enhanced performance when applied in the later sessions following cathodal tDCS. Our results indicate that both anodal and cathodal tDCS can improve planning performance as quantified by the Tower of London test. Most importantly, these data demonstrate training-phase-specific effects of tDCS. We propose that excitability decreasing cathodal tDCS mediates its early beneficial effect through noise reduction of neuronal activity, whereas a further adaptive configuration of specific neuronal connections is supported by excitability enhancing anodal tDCS in the later training phase by enhanced efficacy of active connections. This gain of function was sustained in a follow-up 6 and 12 months after training. In conclusion, the specific coupling of stimulation and training phase interventions may support the treatment of cognitive disorders involving frontal lobe functions.
Solid State Gas Sensor Research in Germany – a Status Report
2009-06-03

This status report overviews activities of the German gas sensor research community. It highlights recent progress in the field of potentiometric, amperometric, conductometric, impedimetric, and field effect-based gas sensors. It is shown that besides step-by-step improvements of conventional principles, e.g. by the application of novel materials, novel principles turned out to enable new markets. In the field of mixed potential gas sensors, novel materials allow for selective detection of combustion exhaust components. The same goal can be reached by using zeolites for impedimetric gas sensors. Operando spectroscopy is a powerful tool to learn about the mechanisms in n-type and in p-type conductometric sensors and to design knowledge-based improved sensor devices. Novel deposition methods are applied to gain direct access to the material morphology as well as to obtain dense thick metal oxide films without high temperature steps. Since conductometric and impedimetric sensors have the disadvantage that a current has to pass the gas sensitive film, film morphology, electrode materials, and geometrical issues affect the sensor signal. Therefore, one tries to measure directly the Fermi level position either by measuring the gas-dependent Seebeck coefficient at high temperatures or at room temperature by applying a modified miniaturized Kelvin probe method, where surface adsorption-based work function changes drive the drain-source current of a field effect transistor.
Optical spectra obtained from amorphous films of rubrene: Evidence for predominance of twisted isomer
2009-06-03

In order to investigate the optical properties of rubrene we study the vibronic progression of the first absorption band (lowest π→π∗ transition). We analyze the dielectric function ε2 of rubrene in solution and thin films using the displaced harmonic oscillator model and derive all relevant parameters of the vibronic progression. The findings are supplemented by density functional calculations using B3LYP hybrid functionals. Our theoretical results for the molecule in two different conformations, i.e., with a twisted or planar tetracene backbone, are in very good agreement with the experimental data obtained for rubrene in solution and thin films. Moreover, a simulation based on the monomer spectrum and the calculated transition energies of the two conformations indicates that the thin film spectrum of rubrene is dominated by the twisted isomer.
Improving Peptide Identification in Proteome Analysis by a Two-Dimensional Retention Time Filtering Approach
2009-06-03

The combination of a two-dimensional peptide separation scheme based on reversed-phase and ion-pair reversed phase HPLC with a computational method to model and predict retention times in both dimensions is described. The algorithm utilizes statistical learning to establish a retention model from about 200 peptide retention times and their corresponding sequences. The application of retention time prediction to the peptides facilitated an increase in true positive peptide identifications upon lowering mass spectrometric scoring thresholds and concomitantly filtering out false positives on the basis of predicted retention times. An approximately 19% increase in the number of peptide identifications at a q-value of 0.01 was achievable in a whole proteome measurement.