julilili42/papers huggingface dataset:
Nodal quasiparticle lifetimes in cuprate superconductors
2005-12-13

A new generation of angular-resolved photoemission spectroscopy (ARPES)\\nmeasurements on the cuprate superconductors offer the promise of enhanced\\nmomentum and energy resolution. In particular, the energy and temperature\\ndependence of the on-shell nodal (k_x=k_y) quasiparticle scattering rate can be\\nstudied. In the superconducting state, low temperature transport measurements\\nsuggest that one can describe nodal quasiparticles within the framework of a\\nBCS d-wave model by including forward elastic scattering and spin-fluctuation\\ninelastic scattering. Here, using this model, we calculate the temperature and\\nfrequency dependence of the on-shell nodal quasiparticle scattering rate in the\\nsuperconducting state which determines the momentum width of the ARPES momentum\\ndistribution curves. For a zero-energy quasiparticle at the nodal momentum k_N,\\nboth the elastic and inelastic scattering rate show a sudden decrease as the\\ntemperature drops below Tc, reflecting the onset of the gap amplitude. At low\\ntemperatures the scattering rate decreases as T^3 and approaches a zero\\ntemperature value determined by the elastic impurity scattering. For T&gt;T_c, we\\nfind a quasilinear dependence on T. At low reduced temperatures, the elastic\\nscattering rate for the nodal quasiparticles exhibits a quasilinear increase at\\nlow energy which arises from elastic scattering processes. The inelastic\\nspin-fluctuation scattering leads to a low energy omega^3 dependence which, for\\nomega&gt;~Delta_0, crosses over to a quasilinear behavior.\\n
T-DHT: Topology-based Distributed Hash Tables
2005-12-13

In this paper, the authors introduced topology-based distributed hash tables (T-DHT) as an infrastructure for data-centric storage, information processing, and routing in ad hoc and sensor networks. T-DHTs do not rely on location information and work even in the presence of voids in the network. Using a virtual coordinate system, a distributed hash table which is strongly oriented to the underlying network topology was constructed. Thus, adjacent areas in the hash table commonly have a direct link in the network. Routing in the T-DHT guarantees reachability and introduces low hop-overhead compared with the shortest path.
Quantitative determination of piritramide in human plasma and urine by off‐ and on‐line solid‐phase extraction liquid chromatography coupled to tandem mass spectrometry
2005-12-13

Abstract A method for the liquid chromatography/tandem mass spectrometric (LC/MS/MS) quantification of piritramide, a synthetic opioid, in plasma after conventional off‐line solid‐phase extraction (SPE) and in urine by on‐line SPE‐LC/MS/MS in positive electrospray mode was developed and validated. Applicability of the on‐line approach for plasma samples was also tested. Deuterated piritramide served as internal standard. For the off‐line SPE plasma method mixed cation‐exchange SPE cartridges and a 150 × 2 mm C18 column with isocratic elution were used. For the on‐line SPE method, a Waters Oasis HLB extraction column and the same C18 analytical column in a column‐switching set‐up with gradient elution were utilized. All assays were linear within a range of 0.5–100 ng/mL with a limit of detection of 0.05 ng/mL. The intra‐ and interday coefficients of variance ranged from 1.3 to 6.1% for plasma and 0.5 to 6.4% for urine, respectively. The extraction recovery for the off‐line plasma assay was between 90.7 and 100.0%. Influence of matrix effects, and freeze/thaw and long‐term stability were validated for both approaches; influence of urine pH additionally for quantification in urine. Copyright © 2005 John Wiley &amp; Sons, Ltd.
Clustering-based Approach to Identify Solutions for the Inference of Regulatory Networks
2005-12-13

In this paper we address the problem of finding valid solutions for the problem of inferring gene regulatory networks. Different approaches to directly infer the dependencies of gene regulatory networks by identifying parameters of mathematical models can be found in literature. The problem of reconstructing regulatory systems from experimental data is often multimodal and thus appropriate optimization strategies become necessary. Thus, we propose to use a clustering based niching evolutionary algorithm to maintain diversity in the optimization population to prevent premature convergence and to raise the probability of finding the global optimum by identifying multiple alternative networks. With this set of alternatives, the identification of the true solution has then to be addressed in a second post-processing step
Robot Navigation Using Biosonar for Natural Landmark Tracking
2005-12-13

A biosonar based mobile robot navigation system is presented for the natural landmark classification using acoustic image matching. The aim of this approach is to take advantage of the perceived properties of bats' prey and landmark identification mechanisms for mobile robots' tracking of natural landmarks. Recognizing natural landmarks like trees through sequential echolocation and acoustic image analyzing allows mobile robot to update its location in the natural environment. In this work, a working implementation of the biosonar system on a mobile robot is shown. It collects sequential echoes to produce acoustic images through digital signal processing (DSP), then compresses images with discrete cosine transform or pyramid algorithm. Fast normalized cross correlation (FNCC) and kernel principal component analysis (KPCA) are respectively used to make the final classification. Experimental result indicates that a mobile robot can achieve the ability of natural landmark classification only based on biomemetic sonar, the topological congruency of the relational structure with cross correlation in acoustic images is reliable in time domain, while the kernel principle component analysis based classification is robust in frequency domain and demands fewer echolocation for landmark classification.
The effect of single‐dose naproxen on eicosanoid formation in human gastroduodenal mucosa
2005-12-13

Summary Background In animal studies, aspirin and non‐aspirin non‐steroidal anti‐inflammatory drugs contribute to gastroduodenal damage via cyclo‐oxygenase inhibition and consecutive leucotriene formation (COX‐LOX eicosanoid shunt). Aim and methods Ten Helicobacter pylori ‐negative healthy volunteers received a single dose of 500 mg naproxen to address two questions: (i) is there a crosstalk between eicosanoids before medication in the human gastroduodenal mucosa and (ii) can we demonstrate a COX‐LOX shunt following single‐dose naproxen? Results Significant correlations in the stomach mucosa before medication were obtained between leucotriene B4 (LTB4) and thromboxane B 2 (TxB 2 ; r = −0.38, P = 0.05), as well as LTB4 and prostaglandin E 2 (PGE 2 ; r = 0.71, P &lt; 0.0001). In serum, a &gt;90% inhibition of TxB 2 and PGE 2 occurred within 30 min of naproxen administration. In gastric mucosa, a significant decrease of TxB 2 occurred already at 15 min and preferably in the antrum. For LTB4 there was a non‐significant trend towards a transient increase. Mucosal PGE 2 was unchanged in all regions; transcript levels of both cyclo‐oxygenases/5‐lipoxygenase were unaffected (except for a trend of increasing cyclo‐oxygenase‐2 in the corpus). Conclusions Baseline correlations between LTB4‐TxB 2 and LTB4‐PGE 2 reflect a crosstalk between these eicosanoids. A COX‐LOX shunt; however, cannot be demonstrated following single‐dose naproxen in a low‐risk population.
The Gluon Propagator in Lattice Landau Gauge with twisted boundary conditions
2005-12-14

We investigate the infrared behaviour of the gluon propagator in Landau gauge on a lattice with twisted boundary conditions.Analytic calculations using Dyson-Schwinger equations, exact renormalization group and stochastic quantization show that the gluon propagator in Landau gauge approaches zero for small momentum.On the other hand lattice calculations and calculations on a four-torus seem to give rise to a non-zero limit.One possible reason for this difference is the existence of zero-momentum fluctuation modes which potentially give a massive contribution to the gluon propagator.Our simulations show that with twisted boundary conditions these zero-momentum modes are suppressed and the gluon propagator becomes smaller than in a periodic ensemble.
When T Cells Get Old
2005-12-14

Why is vaccination against infectious diseases less effective in older patients than in younger ones? Why do the elderly suffer from more frequent and severe infectious episodes than the young? The answer to both these questions is immunosenescence--the poorly defined changes that occur in the immune system as a result of the disrupted performance of multiple components of immunity. Presentations from a recent workshop, which are summarized here, examined these questions and provided some insights from the perspective of improving vaccination strategies among the elderly.
A toy model of (grand) unified monopoles
2005-12-14

We explore the old idea that, in a theory containing several gauge groups, the topological defects of one gauge group coincide with those of another gauge group. This simple 'unification' constraint has deep consequences, the best known of which is a natural explanation of the fractional electric charge of quarks. Here we explore the consequences of this idea for the phase diagram, in a toy model U(1)x U(1).
The Center Vortex Field Propagator
2005-12-14

By using the method of center projection the center vortex part of the gauge field is isolated and its propagator is evaluated in the center Landau gauge, which minimizes the open 3-dimensional Dirac volumes of non-trivial center links bounded by the closed 2-dimensional center vortex surfaces.The center field propagator is found to dominate the gluon propagator (in Landau gauge) in the low momentum regime and to give rise to an OPE correction to the latter of √ σ /p 3 .The screening mass of the center vortex field vanishes above the critical temperature of the deconfinement phase transition, which naturally explains the second order nature of this transition consistently with the vortex picture.Finally, the ghost propagator of maximal center gauge is found to be infrared finite and thus shows no signal of confinement.
Center Vortex Model for SU(3) Yang-Mills Theory
2005-12-14

The center vortex model for the infrared sector of SU(3) Yang-Mills theory is reviewed.After discussing the physical foundations underlying the model, some technical aspects of its realisation are discussed.The confining properties of the model are presented in some detail and compared to known results from full lattice Yang-Mills theory.Particular emphasis is put on the new phenomenon of vortex branching, which is instrumental in establishing first order behaviour of the SU(3) phase transition.Finally, the vortex free energy is verified to furnish an order parameter for the deconfinement phase transition.It is shown to exhibit a weak discontinuity at the critical temperature, in agreement with predictions from lattice gauge theory.
Topologically non-trivial field configurations - interplay of vortices and Dirac eigenmodes
2005-12-14

Gluon field configurations with non-trivial topology like instantons, magnetic monopoles and center vortices play a crucial role in QCD and, in particular, for the spontaneous breaking of chiral symmetry.Moreover, center vortices are strongly correlated with confinement.We present evidence, that there is a deep connection between the topology of gauge fields and center vortices.We use the chirally improved lattice Dirac operator to compute eigenvectors and eigenvalues of various lattice gauge field configurations.Removing vortices from thermalized configurations also removes the topological content of the gauge field.As a consistency check, we apply random changes to the raw configurations.
Cathepsin D Is Present in Human Eccrine Sweat and Involved in the Postsecretory Processing of the Antimicrobial Peptide DCD-1L
2005-12-15

The protein pattern of healthy human eccrine sweat was investigated and 10 major proteins were detected from which apolipoprotein D, lipophilin B, and cathepsin D (CatD) were identified for the first time in human eccrine sweat. We focused our studies on the function of the aspartate protease CatD in sweat. In vitro digestion experiments using a specific fluorescent CatD substrate showed that CatD is enzymatically active in human sweat. To identify potential substrates of CatD in human eccrine sweat LL-37 and DCD-1L, two antimicrobial peptides present in sweat, were digested in vitro with purified CatD. LL-37 was not significantly digested by CatD, whereas DCD-1L was cleaved between Leu(44) and Asp(45) and between Leu(29) and Glu(30) almost completely. The DCD-1L-derived peptides generated in vitro by CatD were also found in vivo in human sweat as determined by surface-enhanced laser desorption/ionization (SELDI) mass spectrometry. Furthermore, besides the CatD-processed peptides we identified additionally DCD-1L-derived peptides that are generated upon cleavage with a 1,10-phenanthroline-sensitive carboxypeptidase and an endoprotease. Taken together, proteolytic processing generates 12 DCD-1L-derived peptides. To elucidate the functional significance of postsecretory processing the antimicrobial activity of three CatD-processed DCD-1L peptides was tested. Whereas two of these peptides showed no activity against Gram-positive and Gram-negative bacteria, one DCD-1L-derived peptide showed an even higher activity against Escherichia coli than DCD-1L. Functional analysis indicated that proteolytic processing of DCD-1L by CatD in human sweat modulates the innate immune defense of human skin.
A Nomenclature for Signal Regulatory Protein Family Members
2005-12-15

Signal regulatory proteins (SIRPs) constitute a family of structurally related surface receptors expressed on leukocytes as well as other cells. SIRPs are characterized by the presence of Ig-like domains and form a subfamily within the Ig superfamily. In the accompanying review ([1][1]), we provide
Experimental Data vs. Diachronic Typological Data: Two Types of Evidence for Linguistic Relativity
2005-12-15

It will be shown that obligatory vs. optional number marking influences not only nonverbal categorization of speakers as shown by recent studies (Imai and Gentner 1997, Lucy 1992a and b, Lucy and Gaskins 2001), but also the way nouns for certain types of objects are created in different languages. We thus have to assume that typological factors do influence lexical change and that there are important links between nonverbal categorization and lexical change.
3D-radiation hydro simulations of disk-planet interactions
2005-12-16

We study the evolution of an embedded protoplanet in a circumstellar disk using the 3D-Radiation Hydro code TRAMP, and treat the thermodynamics of the gas properly in three dimensions. The primary interest of this work lies in the demonstration and testing of the numerical method. We show how far numerical parameters can influence the simulations of gap opening. We study a standard reference model under various numerical approximations. Then we compare the commonly used locally isothermal approximation to the radiation hydro simulation using an equation for the internal energy. Models with different treatments of the mass accretion process are compared. Often mass accumulates in the Roche lobe of the planet creating a hydrostatic atmosphere around the planet. The gravitational torques induced by the spiral pattern of the disk onto the planet are not strongly affected in the average magnitude, but the short time scale fluctuations are stronger in the radiation hydro models. An interesting result of this work lies in the analysis of the temperature structure around the planet. The most striking effect of treating the thermodynamics properly is the formation of a hot pressure-supported bubble around the planet with a pressure scale height of rather than a thin Keplerian circumplanetary accretion disk.
TheBeppoSAXview of the galactic high-mass X-ray binary 4U 0114+65
2005-12-16

A pointed observation of the galactic high-mass X-ray binary 4U 0114+65 was carried out with BeppoSAX to compare the X-ray spectral and timing characteristics observed by this satellite over the broadest range of energies thus far (1.5-100 keV) with the information previously obtained with other spacecraft. The light curve of 4U 0114+65 shows a large flare at the beginning of the BeppoSAX pointing and no significant hardness evolution either during the flare or in the low state occurring after the flare itself. The modulation at ~2.7 h, attributed to the accreting neutron star (NS) spin periodicity, is not significantly detected in our data, although fluctuations with timescales of ~3 h can be seen in the 2-10 keV light curve. Shorter modulations down to timescales of minutes are also found and interpreted as due to accretion of matter onto the NS. The flaring and the low state spectra of 4U 0114+65 can be equally well fitted either with a power law modulated by a high-energy exponential cutoff or with a Comptonization model. During the low state the presence, although tentative, of a thermal component (with kT ̃ 0.3 keV) at low energies, possibly produced by an ionized plasma cloud around the NS, cannot be excluded. Contrary to previous claims, a cyclotron resonant feature in absorption at ~22 keV was not detected in the BeppoSAX spectroscopic data, whereas evidence for a Fe emission line around 6.4 keV is found only during the low state emission. Using all of the above information, a scenario for the system in which the NS is embedded in, and accreting from, a low angular momentum gas cloud is envisaged.
The Roles of Serum Response Factor (SRF) in Development and Function of the Brain
2005-12-16

This chapter contains sections titled: Abstract Serum Response Factor as a Transcription Factor Neuronal Expression Patterns of SRF and Partner Proteins SRF Target Genes with Brain Functions Essential Requirement for SRF in Neuronal Migration SRF and Partner Proteins in Neurite Outgrowth and Axonal Guidance SRF-Mediated Gene Expression in Learning and Memory SRF in Neurological Disorders Perspectives Acknowledgments Abbreviations
Interaction and Fusion of Elementary Systems
2005-12-17

The notion due to R.G. Newton and E.P. Wigner (1949) of an elementary system ES is sharpened to a system on a Lie group G-manifold as configuration space and the unitary irreducible representations (IR) of G as states. We study pairs of elementary systems with configuration space taken as the direct product (G×G)-manifold and with an interaction invariant under the right action of the subgroup diag(G×G). The (G×G)-manifoldis split into a new external group manifold 〈X〉 transformed by left action, and a new internal group manifold 〈x〉 unchanged under diag(G×G). By use of Kronecker products we transform IR pair states to external/internal coordinates. The general concept of fusion due to de Broglie (1932–34) is expressed in the new coordinates as the limit where x goes to the identity element. For elementary Poincaré systems, the distinction between massive Mackey and covariant fields becomes crucial. The presence of a full Poincaré-manifold and of corresponding observables are illuminated by position operators. The space translation parameters of the Poincaré group are related to the relativistic position operators of Newton and Wigner. For two Dirac elementary systems of equal mass m we recover by fusion the field of Bargmann and Wigner (1948) of spin S=1 which can be rewritten in terms of a massive vector field. The total mass of the Bargmann-Wigner field is shown to be minimal, M=2m. Interaction schemes are sketched for pairs of Euclidean and Poincaré-manifolds and ES. By Frobenius reciprocity, the process of fusion allows for a counterpart termed scission. Scission is constructed by use of the theory of induced representations.
Multimodal imaging of brain reorganization in motor areas of the contralesional hemisphere of well recovered patients after capsular stroke
2005-12-19

Clinical recovery after stroke can be significant and has been attributed to plastic reorganization and recruitment of novel areas previously not engaged in a given task. As equivocal results have been reported in studies using single imaging or electrophysiological methods, here we applied an integrative multimodal approach to a group of well-recovered chronic stroke patients (n = 11; aged 50-81 years) with left capsular lesions. Focal activation during recovered hand movements was assessed with EEG spectral analysis and H2(15)O-PET with EMG monitoring, cortico-cortical connectivity with EEG coherence analysis (cortico-cortical coherence) and corticospinal connectivity with transcranial magnetic stimulation (TMS). As seen from comparisons with age-matched controls, our patients showed enhanced recruitment of the lateral premotor cortex of the lesioned hemisphere [Brodmann area (BA) 6], lateral premotor and to a lesser extent primary sensorimotor and parietal cortex of the contralesional hemisphere (CON-H; BA 4 and superior parietal lobule) and left cerebellum (patients versus controls, Z > 3.09). EEG coherence analysis showed that after stroke cortico-cortical connections were reduced in the stroke hemisphere but relatively increased in the CON-H (ANOVA, contrast analysis, P < 0.05), suggesting a shift of functional connectivity towards the CON-H. Nevertheless, fast conducting corticospinal transmission originated exclusively from the lesioned hemisphere. No direct ipsilateral motor evoked potentials (MEPs) could be elicited with TMS over the contralesional primary motor cortex (iM1) in stroke patients. We conclude that (i) effective recovery is based on enhanced utilization of ipsi- and contralesional resources, (ii) basic corticospinal commands arise from the lesioned hemisphere without recruitment of ('latent') uncrossed corticospinal tract fibres and (iii) increased contralesional activity probably facilitates control of recovered motor function by operating at a higher-order processing level, similar to but not identical with the extended network concerned with complex movements in healthy subjects.
‘Eavesdropping’ in wild rough-toothed dolphins ( Steno bredanensis )?
2005-12-19

Several authors suggest that dolphins use information obtained by eavesdropping on echoes from sonar signals of conspecifics, but there is little evidence that this strategy is used by dolphins in the wild. Travelling rough-toothed dolphins ( Steno bredanensis ) either exhibit asynchronous movements or an extremely synchronized swimming behaviour in tight formations, which we expect to facilitate eavesdropping. Therefore, we determined, whether either one or more dolphins were echolocating in subgroups that were travelling with asynchronous and synchronized movements. Since, the number of recording sequences in which more than one animal produced sonar signals was significantly lower during synchronized travel, we conclude that the other members of a subgroup might get information on targets ahead by eavesdropping. Synchronized swimming in tight formations might be an energetic adaptation for travelling in a pelagic dolphin species that facilitates eavesdropping.
Effects of motor activity on the organization of primary somatosensory cortex
2005-12-19

Recent studies have shown that adaptation of representational maps within the primary somatosensory cortex can be induced by task-related motor activity. Here, we explore the relationship between the complexity of the motor task and the extent of task-specific adaptation within the primary somatosensory cortex. We hypothesized that the extent of adaptation increases with the complexity of the motor task. Using neuromagnetic source imaging based on electrical stimulation of the thumb and ring finger, we demonstrate that cortical finger representations are more distant during performance of the pinch finger grip than in a rest condition. Our data suggest that somatosensory cortical maps undergo rapid modulation depending on the task-specific involvement of somatosensory feedback in movements.