julilili42/papers huggingface dataset:
The central engines of radio-loud quasars
2003-09-29

\\n We have assembled a sample of 37 radio-loud quasars that have been\\nimaged with the Hubble Space Telescope in order to investigate\\ntheir black hole masses, accretion rates, and the structure of their\\naccretion disks. The black hole masses were estimated from the\\nluminosities of the host galaxies, and the accretion powers were extrapolated\\nfrom the emission-line luminosities. The majority of the quasars have masses\\nin the range . Their accretion rates,\\n times the Eddington rate, suggest that\\nmost of the objects possess standard optically thick, geometrically thin\\naccretion disks, in some cases perhaps accompanied by an optically thin\\nadvection-dominated component. The coexistence of strong radio emission\\nand a standard disk conflicts with recent models for jet formation. We\\ndiscuss modifications of the standard model that can resolve this discrepancy.\\nWe find there is a strong correlation between the accretion rate and\\nthe extended radio luminosity. This lends support to the idea that the extended\\nradio emission is somehow linked to the accretion disk. Lastly, we combine\\nthe present sample of radio-loud quasars with the sample of BL Lac objects\\nstudied by Wang et al. (2002) to reevaluate the unification picture\\nfor radio-loud active galactic nuclei. Consistent with\\ncurrent ideas for the unification of radio-loud sources, we\\nfind that flat-spectrum radio quasars and FR II radio galaxies indeed\\nseem to belong to the same population, as do BL Lac objects and FR I radio\\ngalaxies on the opposite end of the luminosity spectrum. However, some\\nmembers of the low frequency-peaked BL Lac objects may be more closely\\nassociated with FR II rather than FR I radio galaxies. We describe how the\\nvarious subclasses of radio-loud sources can be viewed as a continuous\\nsequence of varying accretion rate.\\n\\n \\n
Expectation values of four-quark operators in the nucleon
2003-09-29

We calculate expectation values of QCD operators consisting of the products\\nof the four operators of the light quarks corresponding to the scalar,\\npseudoscalar, vector, pseudovector (axial) and tensor Lorentz structures in the\\nnucleon. All combinations of the light flavors are considered. For the\\nevaluation we use elements of the Perturbative Chiral Quark Model (PCQM),\\napproximating the contribution of the valence quarks by the contribution of the\\nPCQM constituent quarks. The contribution of the sea quarks is treated by\\naveraging over the QCD pions with the distribution of the pion field being\\ndetermined by the PCQM. For quarks with the same flavor the expectation values\\nare dominated by the contribution of the sea-quarks. In the scalar case the\\ncontribution of the sea quarks is dominated by the "disconnected terms" were\\none of the pairs of the quark operators acts on the vacuum while the other one\\nacts on the quarks of the pion. The role of the interference terms with one of\\nthe quark pairs acting on the sea quarks and another one acting on the valence\\nquarks increases for quarks with different flavors. The result for the scalar\\ncondensate is compared to the one obtained earlier in the framework of the\\nNambu -Jona-Lasinio model.\\n
Cav1.3 (α1D) Ca2+ Currents in Neonatal Outer Hair Cells of Mice
2003-09-30

Outer hair cells (OHC) serve as electromechanical amplifiers that guarantee the unique sensitivity and frequency selectivity of the mammalian cochlea. It is unknown whether the afferent fibres connected to adult OHCs are functional. If so, voltage‐activated Ca 2+ channels would be required for afferent synaptic transmission. In neonatal OHCs, Ca 2+ channels seem to play a role in maturation since OHCs from Ca v 1.3‐deficient (Ca v 1.3 −/− ) mice degenerate shortly after the onset of hearing. We therefore studied whole‐cell Ca 2+ currents in outer hair cells aged between postnatal day 1 (P1) and P8. OHCs showed a rapidly activating inward current that was 1.8 times larger with 10 m m Ba 2+ as charge carrier ( I Ba ) than with equimolar Ca 2+ ( I Ca ). I Ba started activating at −50 mV with V max =−1.9 ± 6.9 mV, V 0.5 =−15.0 ± 7.1 mV and k = 8.2 ± 1.1 mV ( n = 34 ). The peak I Ba showed negligible inactivation (3.6 % after 300 ms) whereas the I Ca (10 m m Ca 2+ ) was inactivated by 50.7 %. OHC I Ba was reduced by 33.5 ± 10.3 % ( n = 14 ) with 10 μ m nifedipine and increased to 178.5 ± 57.8 % ( n = 14 ) by 5 μ m Bay K 8644. A dose‐response curve for nifedipine revealed an IC 50 of 2.3 μ m , a Hill coefficient of 2.7 and a maximum block of 36 %. Average I Ba density in OHCs was 24.4 ± 10.8 pA pF −1 ( n = 105 ) which is only 38 % of the value in inner hair cells. Single cell RT‐PCR revealed expression of Ca v 1.3 in OHCs. In OHCs from Ca v 1.3 −/− mice, Ba 2+ current density was reduced to 0.6 ± 0.5 pA pF −1 ( n = 9 ) indicating that &gt; 97 % of the Ca 2+ channel current in OHCs flows through Ca v 1.3.
COULD MAGMA TRANSPORT AND ACCUMULATION BE A USEFUL ANALOGUE TO UNDERSTAND HYDROCARBON EXTRACTION?
2003-09-30

The process of magma transport and accumulation is proposed as an analogue for oil and gas extraction from their source rocks and oil shales.Magma accumulation is a highly-dynamic stepwise process, where magma moves inside and with hydrofractures.This may lead to a self-organized critical state, which cannot be described by classical Darcian-type models for flow through intergranular pores or fractures.It was suggested that the same could occur in natural oil and gas extraction, and may perhaps be applied to improve fuel production from oil shales.
Problem-Solving Skills in Anesthesia
2003-09-30

Die Entwicklung von Humanressourcen wie Problemlosefahigkeit und Teamarbeit ist fur Unternehmen in Hochrisikobranchen notwendig, da die hier arbeitenden Menschen im Stande sein mussen, seltene aber riskante Zwischenfalle zu bewaltigen. Trainings sind domainspezifisch auf der Grundlage der Analyse von Fahigkeitsanforderungen zu entwickeln. Zur Entwicklung eines Trainings allgemeiner Problemlosefahigkeiten fur Narkosearzte wurden Anforderungen eruiert. Der Arbeitsplatz OP-Raum hat Merkmale eines komplexen Systems: hohe Dynamik, Intransparenz, Risiko. Problemlosen unter diesen Bedingungen beansprucht bestimmte kognitive und kommunikative Fahigkeiten. Der Beitrag geht der Frage nach, welche das sind und in welchem Ausmas diese Fahigkeiten aus der Sicht von Narkosearzten fur professionelles Zwischenfallmanagement notwendig sind. Erforderliche Problemlosefahigkeiten wurden mit einem multimodalen Verfahren erhoben, bestehend aus Feldbeobachtung, Experteninterviews (N=3), Fragebogen (N=38) und einem Expertenhearing (N=5 Narkosearzte mit Lehrfunktionen). Die Resultate zeigen, dass zur Bewaltigung von Narkoseproblemen primar Fahigkeiten der Handlungsorganisation, der Teaminteraktion und der Einsatz von Heuristiken notwendig sind: Narkosearzte schatzen Fahigkeiten fur bedeutsam ein, mit denen man den Uberblick uber Probleme behalt, zu einfachen, linearen Planen gelangt und koordiniert im OP-Team vorgeht. Von den verwendeten Erhebungsmethoden eignen sich insbesondere qualitative und narrative Verfahren (Interview, offene Fragebogen-Items), um ein breites Spektrum von Problemlosefahigkeiten zu erfassen. URN: urn:nbn:de:0114-fqs0303115
Causes of intravenous medication errors: an ethnographic study
2003-10-01

Training needs and design issues should be addressed to reduce the rate of IV drug preparation and administration errors. This needs a coordinated approach from practitioners, regulators, and the pharmaceutical industry.
Identification and characterization of a novel autolysin (Aae) with adhesive properties from Staphylococcus epidermidis
2003-10-01

Staphylococcus epidermidis biofilm formation on polymer surfaces is considered a major pathogenicity factor in foreign-body-associated infections. Previously, the 148 kDa autolysin AtlE from S . epidermidis , which is involved in the initial attachment of the cells to polymer surfaces and also binds to the extracellular matrix protein vitronectin, was characterized. Here, the characterization of a novel autolysin/adhesin (Aae) in S . epidermidi s is described. Aae was identified as a 35 kDa surface-associated protein that has bacteriolytic activity and binds vitronectin. Its N-terminal amino acid sequence was determined and the respective gene, aae , was cloned. DNA-sequence analysis revealed that aae encodes a deduced protein of 324 amino acids with a predicted molecular mass of 35 kDa. Aae contains three repetitive sequences in its N-terminal portion. These repeats comprise features of a putative peptidoglycan binding domain (LysM domain) found in a number of enzymes involved in cell-wall metabolism and also in some adhesins. Expression of aae by Escherichia coli and subsequent analysis revealed that Aae possesses bacteriolytic activity and adhesive properties. The interaction of Aae with fibrinogen, fibronectin and vitronectin was found to be dose-dependent and saturable and to occur with high affinity, by using the real-time Biomolecular Interaction Analysis (BIA). Aae binds to the A α - and B β -chains of fibrinogen and to the 29 kDa N-terminal fragment of fibronectin. In conclusion, Aae is a surface-associated protein with bacteriolytic and adhesive properties representing a new member of the staphylococcal autolysin/adhesins potentially involved in colonization.
Guardians of cell death: the Bcl-2 family proteins
2003-10-01

Apoptosis is mediated through at least three major pathways that are regulated by (i) the death receptors, (ii) the mitochondria and (iii) the ER (endoplasmic reticulum). In most cells, these pathways are controlled by the Bcl-2 family of proteins that can be divided into anti-apoptotic and pro-apoptotic members. Although the overall amino acid sequence homology between the family members is relatively low, they contain highly conserved domains, referred to as BH (Bcl-2 homology) domains (BH1-4), that are essential for homo- and hetero-complex formation, as well as for their cell-death-inducing capacity. Structural and functional analyses revealed that the pro-apoptotic homologues can be subdivided into the Bax subfamily and the growing BH3-only subfamily. Recent data indicate that BH3-only proteins act as mediators that link various upstream signals, including death receptors and DNA damage signalling, to the mitochondrial and the ER pathway. This review discusses recent structural and functional insights into how these subfamilies promote or inhibit cell-death signals, and how these properties may be utilized for development of apoptosis-promoting small molecules, e.g. in cancer therapy.
Modeling of karst aquifer genesis: Influence of exchange flow
2003-10-01

This paper presents a numerical model study simulating the early karstification of a single conduit embedded in a fissured system. A hybrid continuum‐discrete pipe flow model (CAVE) is used for the modeling. The effects of coupling of the two flow systems on type and duration of early karstification are studied for different boundary conditions. Assuming fixed head boundaries at both ends of the conduit, coupling of the two flow systems via exchange flow between the conduit and the fissured system leads to an enhanced evolution of the conduit. This effect is valid over a wide range of initial conduit diameters, and karstification is accelerated by a factor of about 100 as compared to the case of no exchange flow. Parameter studies reveal the influence of the exchange coefficient and of the hydraulic conductivity of the fissured system on the development time for the conduit. In a second scenario the upstream fixed head boundary is switched to a fixed flow boundary at a specified flow rate during the evolution, limiting the amount of water draining toward the evolving conduit. Depending on the flow rate specified, conduit evolution may be slowed down or greatly impaired if exchange flow is considered.
A rare leucine codon in adpA is implicated in the morphological defect of bldA mutants of Streptomyces coelicolor
2003-10-01

Summary Streptomycetes are mycelial bacteria that produce sporulating aerial hyphae on solid media. Bald ( bld ) mutants fail to form aerial mycelium under at least some conditions. bldA encodes the only tRNA species able to read the leucine codon UUA efficiently, implying the involvement of a TTA‐containing gene in initiating aerial growth. One candidate for such a gene was bldH , because the bldH109 mutant of Streptomyces coelicolor resembles bldA mutants in some aspects. In the work reported here, adpA c , an S. coelicolor gene similar to the Streptomyces griseus A factor‐regulated adpA g , was found to complement the bldH109 mutant partially at both single and multiple copies. The sequence of adpA c from the bldH109 mutant revealed a frameshift. A constructed in frame deletion of adpA c conferred a bald colony phenotype, and the mutant behaved like bldA mutants and bldH109 in its pattern of extracellular signal exchange. Both adpA c and adpA g contain a TTA codon. A TTA‐free version of adpA c was engineered by replacing the TTA leucine codon with a cognate TTG leucine codon. The adpA (TTA→TTG) gene could partially restore aerial mycelium formation to a bldA mutant when it was followed in cis by the gene ornA , as in the natural chromosomal arrangement. This indicated that the UUA codon in adpA c mRNA is the principal target through which bldA influences morphological differentiation. It also implied that translational arrest at the UUA codon in adpA c mRNA caused a polar effect on the downstream ornA , and that the poor translation of both genes contributes extensively to the deficiency of aerial mycelium formation in bldA mutants. Unlike the situation in S. griseus , adpA c transcription does not depend on the host's γ‐butyrolactone signalling system, at least in liquid cultures. In addition, sigma factor BldN, which is the homologue of an S. griseus sigma factor AdsA that is absent from adpA g mutants of S. griseus , was present in the constructed adpA c null mutant of S. coelicolor .
Deriving a particle system from continuum mechanics for the animation of deformable objects
2003-10-01

Mass-spring and particle systems have been widely employed in computer graphics to model deformable objects because they allow fast numerical solutions. In this work, we establish a link between these discrete models and classical mathematical elasticity. It turns out that discrete systems can be derived from a continuum model by a finite difference formulation and approximate classical continuum models unless the deformations are large. In this work, we present the derivation of a particle system from a continuum model, compare it to the models of classical elasticity theory, and assess its accuracy. In this way, we gain insight into the way discrete systems work and we are able to specify the correct scaling when the discretization is changed. Physical material parameters that describe materials in continuum mechanics are also used in the derived particle system.
Evaluation of pre-existent immunity in patients with primary breast cancer: molecular and cellular assays to quantify antigen-specific T lymphocytes in peripheral blood mononuclear cells.
2003-10-01

Although the clinical relevance of endogenous TAA-specific immunity remains unclear, our findings suggest that patients with primary breast cancer can mount a T cell immune response to their tumor that might be beneficially enhanced by TAA-dependent vaccination strategies in the adjuvant situation.
P‐Glycoprotein and Multidrug Resistance‐associated Protein Mediate Specific Patterns of Multidrug Resistance in Malignant Glioma Cell Lines, but not in Primary Glioma Cells
2003-10-01

Understanding and overcoming multidrug resistance (MDR) may be a promising strategy to develop more effective pharmacotherapies for malignant gliomas. In the present study, human malignant glioma cell lines (n = 12) exhibited heterogeneous mRNAand protein expression and functional activity of the mdr gene‐encoded P‐glycoprotein (PGP) and MDR‐associated protein (MRP). Correlation between mRNA expression, protein levels and functional activity was strong. Inhibition of PGP activity by verapamil or PSC 833 enhanced the cytotoxic effects of vincristine, doxorubicin, teniposide and taxol. Inhibition of MRP activity by indomethacin or probenecid enhanced the cytotoxic effects of vincristine, doxorubicin and teniposide. The human cerebral endothelial cell line, SV‐HCEC, exhibited the strongest PGP activity of all cell lines. Five primary human glioblastomas and one anaplastic astrocytoma displayed heterogenous protein levels of PGP and MRP‐1 in tumor cells and of PGP in biopsy specimens in vivo, but no functional activity of these proteins upon ex vivo culturing. These data suggest that the glioma cell line‐associated MDR‐type drug resistance is a result of long‐term culturing and that cerebral endothelial, but not glioma cells, may contribute to MDR‐type drug resistance of gliomas in vivo.
Ilímaussaq ‘en miniature’: closed-system fractionation in an agpaitic dyke rock from the Gardar Province, South Greenland (contribution to the mineralogy of Ilímaussaq no. 117)
2003-10-01

Abstract Based on petrography, mineral chemistry, and petrology, the physico-chemical evolution of an agpaitic dyke was found to be very similar to that of the neighbouring Ilímaussaq complex. Various mineral assemblages were used to reconstruct the crystallization conditions of the dyke rock for different stages during cooling. The early magmatic phenocryst assemblage is alkali feldspar + nepheline + augite + olivine + magnetite and indicates liquidus temperatures of ∼850oC, silica activities of ∼0.5, and oxygen fugacities of FMQ –1.5 to –3. The groundmass assemblage albite + microcline + nepheline + sodalite + arfvedsonite + aegirine + aenigmatite + astrophyllite indicates lower temperatures of between 600 and 450oC, at silica activities of 0.25, and oxygen fugacities around the FMQ buffer. Amphibole composition strongly responds to fluorite saturation and proves crystallization occurred in a system closed to oxygen. Late-stage hydrothermal conditions are indicated by the conversion of nepheline and sodalite to analcime and the growth of aegirine on arfvedsonite. These late-stage reactions are constrained to temperatures of &lt;300°C, water activities of between 0.5 and unity, and oxygen fugacities above MH. The dyke has to be regarded as a small equivalent of the larger Ilímaussaq complex, in which identical differentiation processes proceeded at a scale very different in terms of magma volume and cooling times.
A geochemical and Sr-Nd-O isotopic study of the Proterozoic Eriksfjord Basalts, Gardar Province, South Greenland: Reconstruction of an OIB signature in crustally contaminated rift-related basalts
2003-10-01

Abstract Basalts from the volcano-sedimentary Eriksfjord Formation (Gardar Province, South Greenland) were erupted at around 1.2 Ga into rift-related graben structures. The basalts have compositions transitional between tholeiite and alkaline basalt with MgO contents &lt;7 wt.% and they display LREE -enrichment relative to a chondritic source. Most of the trace element and REE characteristics are similar to those of basalts derived from OIB-like mantle sources. Initial 87 Sr/ 86 Sr ratios of clinopyroxene separates range from 0.70278 to 0.70383 and initial ε Nd values vary from –3.2 to +2.1. The most unradiogenic samples overlap with the field defined by carbonatites of similar age and can be explained by mixing of isotopically depleted and enriched mantle components. Using AFC modelling equations, the Sr-Nd isotope data of the more radiogenic basalts can successfully be modelled by addition of &lt;5% lower crustal granulite-facies gneisses as contaminants. δ 18 O v-smow values of separated clinopyroxene range from +5.2 to +6.0% and fall within the range of typical mantle-derived rocks. However, up to 10% mixing with an average lower crustal component are permitted by the data.
Descriptive Osteology of the Family Chaudhuriidae (Teleostei, Synbranchiformes, Mastacembeloidei), with a Discussion of Its Relationships
2003-10-01

Abstract The little known earthworm eel family Chaudhuriidae consists of nine small to minute species of Asian freshwater fishes. In this paper, the osteology of seven representatives of the family is described in detail for the first time. We propose a list of 21 synapomorphies to support chaudhuriid monophyly. Reductive characters are: loss of basisphenoid, pterosphenoid, endopterygoid, dermopalatine, pars autopalatina, posttemporal, gill rakers, toothplate on pharyngobranchial two, distal pectoral radials, lateral line canals, dorsal- and anal-fin spines and their supporting pterygiophores, epurals, uroneurals, parhypural, and reduction in numbers of epicentrals and hypurals. Progressive characters are: presence of a long membrane bone process on autosphenotic, a boomerang-shaped ectopterygoid with a long preorbital extension, an anterior process of membrane bone of the metapterygoid, a unique arrangement of dorsal gill arch elements, separate foramina for the three trigeminal branches, and a ventromedian keel on the first vertebra. The new information is used to critically reevaluate previous hypotheses of chaudhuriid relationships. Finally, the issue of miniaturization in chaudhuriid fishes is addressed and discussed.
Impact of parental onchocerciasis and intensity of transmission on development and persistence ofOnchocerca volvulusinfection in offspring: an 18 year follow-up study
2003-10-01

This study analysed the impact and the extent by which parental Onchocerca volvulus infection, intensity of transmission of O. volvulus infective 3rd-stage larvae (L3) and anthropometric factors may influence the acquisition, development and persistence of O. volvulus infection in offspring. A total of 15 290 individuals in 3939 families with 9640 children were surveyed for microfilariae of O. volvulus , and prevalence and level of O. volvulus infection in children aged 0 to 20 years from infected and non-infected parents were followed longitudinally for 18 years. Children from O. volvulus -infected mothers had not only a substantially higher risk to become infected; they also acquired infection earlier in life and developed higher infection levels. Multiple logistic regression analysis showed that maternal O. volvulus infection and children's age are the predominant predictors for patent O. volvulus infection, while the intensity of transmission, measured by the annual transmission potential (ATP) of O. volvulus L3, was less decisive. Longitudinal follow up of children showed that during vector control activities by the Onchocerciasis Control Programme (OCP) and in low-level transmission areas, infection persisted at higher levels in children from O. volvulus -positive mothers. In summary, the dominant risk factor for children to become infected is maternal onchocerciasis, and also age-associated factors will strongly impact on the development of patent O. volvulus infection in offspring.
The Apparent Uptake of Fluorescently Labeled siRNAs by Electroporated Cells Depends on the Fluorochrome
2003-10-01

Transfection of mammalian cells with preformed small interfering RNAs (siRNAs) permits a transient and often specific reduction of gene expression. It is possible to rapidly examine the uptake of siRNAs by transfection with fluorescently labeled siRNAs. We examined the apparent uptake of such siRNAs by several leukemic cell lines after electroporation. We show that Cy3 and Cy5-labeled siRNAs cause a significant amount of cell fluorescence, as judged by flow cytometry. In contrast, several fluorescein-labeled siRNAs could not be detected. Nevertheless, such fluoresceinated siRNAs efficiently suppressed a leukemic target gene, demonstrating that siRNA uptake must have taken place. Therefore, for cell electroporation, fluorescein-labeled siRNAs may lead to false negative results and should not be used to examine electroporation-mediated siRNA uptake.