julilili42/papers huggingface dataset:
A general spike coding model for natural echoes
2002-10-25

Bats navigating in natural environments face a challenging task in identifying landmarks (e.g., vegetation) that are composed of many reflecting facets and hence generate random echo waveforms. The biological substrate for these tasks is a spike code. Informative code features were identified by a computational approach which encoded a natural stimulus ensemble (84&amp;lt;th&amp;gt;800 echoes from four deciduous tree species) using a parsimonious model of spike generation. Interspike intervals spanning more than one cycle at the auditory bandpass filter’s center frequency proved convenient classification substrates because of the following properties: (a) almost certain presence in each echo representation; (b) simple probabilistic description (uncorrelated); (c) undemanding constraints on firing threshold locations and spike time resolution. An m-ary sequential probability ratio test using a first-order characterization of these intervals (number plus sample mean of duration and threshold location) demonstrated good classification performance (0.1% to 1% error probability at &amp;lt;10 expected echoes) as well as remarkable robustness against changes in the spike-model parameters. Distant-cycle intervals are therefore hypothesized to be a primal sketch building block analogous to visual edges, with the notable difference that they do not delineate deterministic shapes [Work supported by DFG, SFB 550 B6.]
Maximum entropy light source placement
2002-10-27

Finding the best viewing parameters for a scene is quite difficult but a very important problem. Fully automatic procedures seem to be impossible as the notion of best strongly depends on the human judgment as well as on the application. In this paper a solution to the sub-problem of placing light sources for given camera parameters is proposed. A light position is defined to be optimal, when the resulting illumination reveals more about the scene as the illuminations from all other light positions, i.e. the light position maximizes the information that is added to the image through the illumination. With the help of an experiment with several subjects we could adapt the information measure to the actually perceived information content. We present fast global optimization procedures and solutions for two and more light sources.
A case study on automatic camera placement and motion for visualizing historical data
2002-10-27

In this paper, we address the problem of automatic camera positioning and automatic camera path generation in the context of historical data visualization. After short description of the given data, we elaborate on the constraints for the positioning of a virtual camera in such a way that not only the projected area is maximized, but also the depth of the displayed scene. This is especially important when displaying terrain models, which do not provide good 3D impression when only the projected area is maximized. Based on this concept, we present a method for computing an optimal camera position for each instant of time. Since the explored data are not static, but change depending on the explored scene time, we also discuss a method for animation generation. In order to avoid sudden changes of the camera position, when the previous method is applied for each frame (point in time), we introduce pseudo-events in time, which expand the bounding box defined by the currently active events of interest. In particular, this technique allows events happening in a future point in time to be taken into account such that when this time becomes current, all events of interest are already within the current viewing frustum of the camera.
A Key Role for Old Yellow Enzyme in the Metabolism of Drugs by Trypanosoma cruzi
2002-10-28

Trypanosoma cruzi is the etiological agent of Chagas' disease. So far, first choice anti-chagasic drugs in use have been shown to have undesirable side effects in addition to the emergence of parasite resistance and the lack of prospect for vaccine against T. cruzi infection. Thus, the isolation and characterization of molecules essential in parasite metabolism of the anti-chagasic drugs are fundamental for the development of new strategies for rational drug design and/or the improvement of the current chemotherapy. While searching for a prostaglandin (PG) F2α synthase homologue, we have identified a novel “old yellow enzyme” from T. cruzi (TcOYE), cloned its cDNA, and overexpressed the recombinant enzyme. Here, we show that TcOYE reduced 9,11-endoperoxide PGH2 to PGF2α as well as a variety of trypanocidal drugs. By electron spin resonance experiments, we found that TcOYE specifically catalyzed one-electron reduction of menadione and β-lapachone to semiquinone-free radicals with concomitant generation of superoxide radical anions, while catalyzing solely the two-electron reduction of nifurtimox and 4-nitroquinoline-N-oxide drugs without free radical production. Interestingly, immunoprecipitation experiments revealed that anti-TcOYE polyclonal antibody abolished major reductase activities of the lysates toward these drugs, identifying TcOYE as a key drug-metabolizing enzyme by which quinone drugs have their mechanism of action.
An Easy Route for the Synthesis of New Axially Substituted Titanium(IV) Phthalocyanines
2002-10-28

A facile synthesis of highly soluble, axially substituted titanium(IV) phthalocyanines is described. The reaction of tetra-tert-butylphthalocyaninatotitanium oxide tBu4PcTiO with the chelating agents 3a−3i containing oxygen or sulfur as donor atoms leads to the formation of axially substituted tBu4PcTiX (X = functionalized catechols, dithiocatechol, and dihydroxynaphthalene). Following the same procedure a dimeric sandwich-like complex could be also synthesized from the reaction of tBu4PcTiO with tetrahydroxy-p-benzoquinone. All compounds were characterized by IR, UV/Vis, MS, 1H and 13C NMR spectroscopy, and elemental analysis. The axially substituted titanium phthalocyanines show high solubility and a low aggregation tendency due to the steric hindrance arising from the asymmetric peripheral substitution pattern of the macrocycle and the presence of bulky axial ligands. The relevant nonlinear optical (NLO) properties of some of the tBu4PcTiX compounds were determined in order to evaluate the potential role of these new compounds in optical limiting. The correlation between tBu4PcTiX structure and NLO properties is analyzed in terms of the electronic effects of the axial ligand.
Proton magnetic resonance spectroscopy with metabolite nulling reveals regional differences of macromolecules in normal human brain
2002-10-28

Abstract Purpose To quantify the macromolecular content in different anatomic brain regions and to evaluate an age dependency of the macromolecular concentrations. Material and Methods A short echo time Stimulated Echo Acquisition Mode (STEAM) sequence was used without and with inversion recovery metabolite nulling in 8–12 healthy volunteers. Quantitation was achieved by an extended LCModel, and macromolecular resonances at 0.9, 1.4, 2.1, and 3.0 ppm were evaluated. Results In the cerebellum, the 1.4, 2.1, and 3.0 ppm resonances were highest compared to all other regions ( P &lt; 0.02); the 0.9 ppm resonance was significantly higher than that of pons ( P &lt; 0.01). In the motor cortex, the 0.9, 1.4, and 2.1 ppm resonances were higher than those of white matter and pons ( P &lt; 0.02). Pons and white matter did not differ significantly from each other. A significant correlation of the macromolecular concentrations with the age could not be found. Conclusion There were higher macromolecular concentrations in the cerebellum and motor cortex than in pons or white matter. These were probably due to the higher portions of gray matter in these volumes of interest (VOIs) than in the other regions. J. Magn. Reson. Imaging 2002;16:538–546. © 2002 Wiley‐Liss, Inc.
On the muon nucleus integrals entering the neutrinoless e conversion rates
2002-10-28

The muon–nucleus integrals which determine the nuclear-structure dependence of the branching ratio Rμe, i.e. the rate of the flavour-changing muon–electron conversion divided by the total rate of the ordinary muon capture, are extensively studied. Precise muon wavefunctions are employed which are obtained by solving the Schrödinger and Dirac equations. To this aim a method based on modern neural network techniques is developed which gives the radial muon wavefunctions as a linear combination of sigmoid functions.
Anomalous longitudinal magnetic field near the surface of copper conductors
2002-10-28

We have used ultracold atoms to characterize the magnetic field near the\\nsurface of copper conductors at room temperature carrying currents between\\n0.045 A and 2 A. In addition to the usual circular field we find an additional,\\n1000 - 10000 times smaller longitudinal field. The field changes its strength\\nperiodically with a period of 200-300 um.\\n
Synthesis and Optical Limiting Properties of Axially Bridged Phthalocyanines: [(tBu4PcGa)2O] and [(tBu4PcIn)2O]
2002-10-28

In the paper by M. Hanack et al., published in Chem. Eur. J. 2002, 8, 4248–4254, the second sentence in the third column of the abstract is incorrect. It should read: The magnitude of the optical limiting exhibited by 1, 2, 3, and 4 in toluene at 532 nm laser pulse irradiation is in the order: 4>3>2>1. The editorial office apologises for this mistake.
Spectroscopic analyses of the “blue hook” stars inωCentauri: A test of the late hot flasher scenario
2002-10-29

omega Cen contains the largest population of very hot horizontal branch (HB) stars known in a globular cluster. Recent UV observations (Whitney et al. 1998; D'Cruz et al. 2000) show a significant population of hot stars below the zero-age horizontal branch (``blue hook'' stars), which cannot be explained by canonical stellar evolution. Stars which suffer unusually large mass loss on the red giant branch and thus experience the helium core flash while descending the white dwarf cooling curve could populate this region. Theory predicts that these ``late hot flashers'' should show higher temperatures than the hottest canonical HB stars and should have helium- and carbon-rich atmospheres. We obtained and analysed medium resolution spectra of a sample of blue hook stars to derive their atmospheric parameters. The blue hook stars are indeed both hotter (Teff > 35,000K) and more helium-rich than classical extreme HB stars. In addition we find indications for a large enhancement of the carbon abundance relative to the cluster abundance.
Modelling Reactive Transport of Organic Solutes in Groundwater with a Lagrangian Streamtube Approach
2002-10-30

This chapter contains sections titled: Introduction Reactive Transport Model SMART Streamtube Approach Accounting for Reactive Processes Numerical Evaluation of Breakthrough Curves Reactive Transport of Phenanthrene and Terrasurf G50 Conceptual Model of Relevant Processes Remediation Scenario Process Parameters Conservative Transport Description Reactive Transport Simulations Influence of Aquifer Properties on Transport of PHE Impact of Non-Ionic Surfactant TG50 on Transport of PHE Summary and Conclusions References
Upscaling of Hydraulic and Hydrogeochemical Aquifer Parameters Using an Approach Based on Sedimentological Facies
2002-10-30

This chapter contains sections titled: Introduction The Three-dimensional Reactive Transport Modelling Approach Facies-based Characterization of Hydraulic and Hydrogeochemical Aquifer Properties Generation of Three-dimensional Facies and Fields of Hydraulic and Hydrogeochemical Aquifer Parameters Modelling of Flow and Reactive Transport Example of Application Conclusions and Future Work References
Characterization of Arabidopsis thaliana AtFKBP42 that is membrane‐bound and interacts with Hsp90
2002-10-31

Summary The twisted dwarf 1 ( twd 1) mutant from Arabidopsis thaliana was identified in a screen for plant architecture mutants. The TWD1 gene encodes a 42 kDa FK506‐binding protein ( At FKBP42) that possesses similarity to multidomain PPIases such as mammalian FKBP51 and FKBP52, which are known to be components of mammalian steroid hormone receptor complexes. We report here for the first time the stoichiometry and dissociation constant of a protein complex from Arabidopsis that consists of At Hsp90 and At FKBP42. Recombinant At FKBP42 prevents aggregation of citrate synthase in almost equimolar concentrations, and can be cross‐linked to calmodulin. In comparison to one active and one inactive FKBP domain in FKBP52, At FKBP42 lacks the PPIase active FKBP domain. While FKBP52 is found in the cytosol and translocates to the nucleus, At FKBP42 was predicted to be membrane‐localized, as shown by electron microscopy.
Spectrum of low-energy excitations in the vortex state: Comparison of the Doppler-shift method to a quasiclassical approach
2002-10-31

We present a detailed comparison of numerical solutions of the quasiclassical\\nEilenberger equations with several approximation schemes for the density of\\nstates of s- and d-wave superconductors in the vortex state, which have been\\nused recently. In particular, we critically examine the use of the Doppler\\nshift method, which has been claimed to give good results for d-wave\\nsuperconductors. Studying the single vortex case we show that there are\\nimportant contributions coming from core states, which extend far from the\\nvortex cores into the nodal directions and are not present in the Doppler shift\\nmethod, but significantly affect the density of states at low energies. This\\nleads to sizeable corrections to Volovik's law, which we expect to be sensitive\\nto impurity scattering. For a vortex lattice we also show comparisons with the\\nmethod due to Brandt, Pesch, and Tewordt and an approximate analytical method,\\ngeneralizing a method due to Pesch. These are high field approximations\\nstrictly valid close to the upper critical field Bc2. At low energies the\\napproximate analytical method turns out to give impressively good results over\\na broad field range and we recommend the use of this method for studies of the\\nvortex state at not too low magnetic fields.\\n
Impaired renal Na+ retention in the sgk1-knockout mouse
2002-11-01

The serum- and glucocorticoid-regulated kinase (sgk1) is induced by mineralocorticoids and, in turn, upregulates heterologously expressed renal epithelial Na(+) channel (ENaC) activity in Xenopus oocytes. Accordingly, Sgk1 is considered to mediate the mineralocorticoid stimulation of renal ENaC activity and antinatriuresis. Here we show that at standard NaCl intake, renal water and electrolyte excretion is indistinguishable in sgk1-knockout (sgk1(-/-)) mice and wild-type (sgk1(+/+)) mice. In contrast, dietary NaCl restriction reveals an impaired ability of sgk1(-/-) mice to adequately decrease Na(+) excretion despite increases in plasma aldosterone levels and proximal-tubular Na(+) and fluid reabsorption, as well as decreases in blood pressure and glomerular filtration rate.
Impaired renal Na+ retention in the sgk1-knockout mouse
2002-11-01

The serum- and glucocorticoid-regulated kinase (sgk1) is induced by mineralocorticoids and, in turn, upregulates heterologously expressed renal epithelial Na+ channel (ENaC) activity in Xenopus oocytes. Accordingly, Sgk1 is considered to mediate the mineralocorticoid stimulation of renal ENaC activity and antinatriuresis. Here we show that at standard NaCl intake, renal water and electrolyte excretion is indistinguishable in sgk1-knockout (sgk1–/–) mice and wild-type (sgk1+/+) mice. In contrast, dietary NaCl restriction reveals an impaired ability of sgk1–/– mice to adequately decrease Na+ excretion despite increases in plasma aldosterone levels and proximal-tubular Na+ and fluid reabsorption, as well as decreases in blood pressure and glomerular filtration rate.
The Extraretinal Eyelet ofDrosophila: Development, Ultrastructure, and Putative Circadian Function
2002-11-01

Circadian rhythms can be entrained by light to follow the daily solar cycle. In Drosophila melanogaster a pair of extraretinal eyelets expressing immunoreactivity to Rhodopsin 6 each contains four photoreceptors located beneath the posterior margin of the compound eye. Their axons project to the region of the pacemaker center in the brain with a trajectory resembling that of Bolwig's organ, the visual organ of the larva. A lacZ reporter line driven by an upstream fragment of the developmental gap gene Krüppel is a specific enhancer element for Bolwig's organ. Expression of immunoreactivity to the product of lacZ in Bolwig's organ persists through pupal metamorphosis and survives in the adult eyelet. We thus demonstrate that eyelet derives from the 12 photoreceptors of Bolwig's organ, which entrain circadian rhythmicity in the larva. Double labeling with anti-pigment-dispersing hormone shows that the terminals of Bolwig's nerve differentiate during metamorphosis in close temporal and spatial relationship to the ventral lateral neurons (LN(v)), which are essential to express circadian rhythmicity in the adult. Bolwig's organ also expresses immunoreactivity to Rhodopsin 6, which thus continues in eyelet. We compared action spectra of entrainment in different fly strains: in flies lacking compound eyes but retaining eyelet (so(1)), lacking both compound eyes and eyelet (so(1);gl(60j)), and retaining eyelet but lacking compound eyes as well as cryptochrome (so(1);cry(b)). Responses to phase shifts suggest that, in the absence of compound eyes, eyelet together with cryptochrome mainly mediates phase delays. Thus a functional role in circadian entrainment first found in Bolwig's organ in the larva is retained in eyelet, the adult remnant of Bolwig's organ, even in the face of metamorphic restructuring.
Non-invasive coronary angiography with high resolution multidetector-row computed tomography. Results in 102 patients
2002-11-01

High resolution MDCT angiography with retrospective gating permits the non-invasive detection of coronary artery stenoses with high accuracy if image quality is optimized for each of the three major coronary arteries.
Ubiquitylation of BAG-1 Suggests a Novel Regulatory Mechanism during the Sorting of Chaperone Substrates to the Proteasome
2002-11-01

BAG-1 is a ubiquitin domain protein that links the molecular chaperones Hsc70 and Hsp70 to the proteasome. During proteasomal sorting BAG-1 can cooperate with another co-chaperone, the carboxyl terminus of Hsc70-interacting protein CHIP. CHIP was recently identified as a Hsp70- and Hsp90-associated ubiquitin ligase that labels chaperone-presented proteins with the degradation marker ubiquitin. Here we show that BAG-1 itself is a substrate of the CHIP ubiquitin ligase in vitro and in vivo. CHIP mediates attachment of ubiquitin moieties to BAG-1 in conjunction with ubiquitin-conjugating enzymes of the Ubc4/5 family. Ubiquitylation of BAG-1 is strongly stimulated when a ternary Hsp70.BAG-1.CHIP complex is formed. Complex formation results in the attachment of an atypical polyubiquitin chain to BAG-1, in which the individual ubiquitin moieties are linked through lysine 11. The noncanonical polyubiquitin chain does not induce the degradation of BAG-1, but it stimulates a degradation-independent association of the co-chaperone with the proteasome. Remarkably, this stimulating activity depends on the simultaneous presentation of the integrated ubiquitin-like domain of BAG-1. Our data thus reveal a cooperative recognition of sorting signals at the proteolytic complex. Attachment of polyubiquitin chains to delivery factors may represent a novel mechanism to regulate protein sorting to the proteasome.
CARD15 mutations in familial granulomatosis syndromes: A study of the original Blau syndrome kindred and other families with large‐vessel arteritis and cranial neuropathy
2002-11-01

Abstract Objective To analyze the CARD15 gene in families with heritable multi‐organ granulomatoses, including the original Blau syndrome kindred as well as other families with related granulomatous conditions. Methods Linkage mapping was performed in 10 families. Observed recombination events were used to exclude regions centromeric or telomeric to 16q12.1, and the Blau gene critical region was refined to &lt;3 cM, corresponding to a physical distance of 3.5 megabasepairs. Based on its known biochemical function, CARD15 was analyzed as a positional candidate for the Blau syndrome susceptibility gene, by direct DNA sequencing. Results These studies resulted in the identification, in 5 of the families, of 2 sequence variants at position 334 of the gene product (R334W and R334Q). Affected family members from the original Blau syndrome kindred were heterozygous for the R334W missense mutation; mutations at the same position were also observed in several unrelated Blau syndrome families, some of whose phenotypes included large‐vessel arteritis and cranial neuropathy. The missense mutations segregated with the disease phenotype in the families, and were not seen in 208 control alleles. Conclusion These findings demonstrate that CARD15 is an important susceptibility gene for Blau syndrome and for other familial granulomatoses that display phenotypic traits beyond those of classic Blau syndrome.
Partial Melting and Assimilation of Dolomitic Xenoliths by Mafic Magma: the Ioko-Dovyren Intrusion (North Baikal Region, Russia)
2002-11-01

A petrological study was carried out on Mg-skarn-bearing dunite cumulates that are part of the Neo-Proterozoic Ioko-Dovyren intrusion (North Baikal region, Russia). Skarn xenoliths contain brucite pseudomorphs after periclase, forsterite and Cr-poor spinel. Fine-grained forsterite–spinel skarns occur with the brucite skarns or as isolated schlieren. Field relationships reveal that the Mg-skarns formed from silica-poor dolomitic xenoliths by interaction with the mafic magma of the Ioko-Dovyren intrusion. Rapid heating of dolomitic xenoliths by the mafic magma caused the decomposition of dolomite into calcite + periclase, releasing much CO2. Further heating quantitatively melted the calcite. A periclase-rich restite was left behind after extraction of the low-density, low-viscosity calcite melt. The extracted calcite melt mixed with the surrounding mafic melt. This resulted in crystallization of olivine with CaO contents up to 1·67 wt %. A local decrease in the silica concentration stabilized CaAl2SiO6-rich clinopyroxene. Brucite/periclase-free forsterite–spinel skarns probably originated by crystallization from the mafic melt close to the xenoliths at elevated fO2. The high fO2 was caused by CO2-rich fluids released during the decomposition of the xenoliths. The above case study provides the first evidence for partial melting of dolomite xenoliths during incorporation by a mafic magma.