Grain orientation in high Tc superconductors by molten salt powder synthesis

The molten salt or the flux method is used to fabricate a grain oriented YBa2Cu3O(7-x) (123) superconductor. Here we suggest a two-stage approach in using the 'green phase', Y2BaCuO5 (211), as seed crystals in the formation of YBa2Cu3O(7-x). The process uses Y2BaCuO5 formed by molten salt synthesis. The Y2BaCuO5 phase was observed to be stable in water and in most of the salt systems. Salt processing can form a small quantity of anisotropic particles of Y2BaCuO5. This material can form the 123 phase when tape cast and sintered in the presence of the required levels of Ba and Cu

Contribution to the occurrence and distribution of culicid mosquitoes in Northrhine-Westphalia with special reference to the greater Bonn area

Mit dem Verschwinden der Malaria aus Deutschland in der Mitte des letzten Jahrhunderts sank auch das wissenschaftliche Interesse an Stechmücken. Seit Jahrzehnten sind keine großflächigen systematischen Studien zum Vorkommen und zur Verbreitung der einheimischen Culicidenarten mehr durchgeführt worden, da diese scheinbar keine Vektorfunktion mehr hatten. Lediglich saisonal bedingte Massenvermehrungen waren und sind Anlass zu gezielten Bekämpfungsaktionen, die auch aktuell regionale Daten zur Stechmückenfauna liefern (BECKER & KAISER 1995). Diese und weitere sporadische Studien aus den letzten Jahren (BASTIAN 2000; HERRMANN 2000; KAMPEN unveröffentl.) zeigen, dass potenzielle Malariaüberträger nach wie vor bei uns heimisch sind. Gerade die anhaltende Diskussion über ‚emerging and resurging infectious diseases’ in Verbindung mit möglichen Klima- und Umweltveränderungen (GRATZ 1999, 2004) sollte aber das allgemeine Interesse an den einheimischen (potenziellen) Vektoren wecken, um für Eventualitäten gewappnet zu sein. Der weltweite Massentourismus und Tierhandel sorgt nicht nur für ein permanentes Angebot an Infektionsquellen für einheimische hämatophage Arthropoden, sondern erleichtert auch die Einschleppung und Ausbreitung von allochthonen Vektoren. So gelangte etwa die Tigermücke Aedes albopictus, ein effizienter Gelbfieber- und Dengue-Vektor, zu Beginn der 1990er Jahre mit dem Gebrauchtreifenhandel nach Südeuropa (KNUDSEN et al. 1996) und wandert seitdem ständig weiter nach Norden (SCHAFFNER 2001; FLACIO et al. 2004; SCHOLTE et al. 2006). Doch auch Zugvögel bringen seit jeher Viren aus afrikanischen Ländern nach Europa undkönnen einheimische Vektoren infizieren (MALKINSON & BANET 2002). Bis auf wenige Ausnahmen blieben große Epidemien bisher aus. Nicht so in Nordamerika, wo 1999 auf bislang unbekanntem Wege das West Nil-Virus eingeschleppt wurde und sich bis 2003 über die gesamten Vereinigten Staaten ausbreitete (GOULD & FIKRIG 2004). Zahlreiche Todesfälle bei Menschen, Pferden und Vögeln, insbesondere auf eine Virusübertragung durch Culex pipiens zurückzuführen, waren die Folge. Mit dem Tahyna-, Sindbis- und West Nil-Virus kursieren mindestens drei pathogene Stechmückenassoziierte Viren auch in Europa (ASPÖCK 1996; LUNDSTRÖM 1999). Erst kürzlich wurde in toten Vögeln in Österreich erstmals das Usutu-Virus außerhalb Afrikas nachgewiesen (WEISSENBÖCK et al. 2002). Ob es humanpathogenes Potenzial hat, ist unbekannt. Schließlich sind Stechmücken als Überträger der caninen Filariose von Bedeutung, die gelegentlich auch den Menschen befallen kann und sich offenbar ebenfalls vom Mittelmeerraum nach Norden ausbreitet (MURO 1999; PAMPIGLIONE & RIVASI 2000). Die vorgestellte Studie soll einen Beitrag zur Aktualisierung unserer Kenntnisse zum Vorkommen, zur Verbreitung und zur Biologie einheimischer Culiciden liefern, die erforderlich sind, um auf autochthone Erregerübertragung in geeigneter Weise reagieren zu können.To update information on the indigenous culicid fauna (Diptera: Culicidae) of western Germany, aquatic mosquito stages were collected by water dipping and adults caught by specialized traps at various Northrhine-Westphalian localities in 2004. Out of 154 water basins checked, 75 turned out to be culicid breeding sites. 1404 larvae and pupae belonging to 17 species were collected. These comprised 7 Aedes-, 4 Culex-, 4 Anopheles- and 2 Culiseta-species. Cx. territans specimens added up to 44.7 % of the larval and pupal catches and together with the three other most abundant species, Cs. annulata (14.7 %), An. maculipennis s.s. (12.3 %) and Cx. torrentium (10 %), amounted to 81.8 % of all larvae and pupae collected. With regard to the adult stages, only 111 specimens belonging to 8 species were trapped probably owing to methodological reasons and/or to the particular mosquito-hostile climatic conditions in the summer of 2004. In contrast to the larval collections, the major part of the adults were Cx. torrentium with 34.2 %, followed by Cx. pipiens s.s. (21.6 %) and An. plumbeus (19.8 %), thus giving a completely different impression on the indigenous population abundances. 105 of the adults were caught by the BG sentinel, a newly developed odour trap emitting a quantified composition of selected mosquito attractants. The other 6 individuals were caught by a CO2-trap, whereas a mere light trap and an ovipositor trap were never successfu

Three Types of Cooling Superfluid Neutron Stars: Theory and Observations

Cooling of neutron stars (NSs) with the cores composed of neutrons, protons, and electrons is simulated assuming $^1$S$_0$ pairing of neutrons in the NS crust, and also $^1$S$_0$ pairing of protons and weak $^3$P$_2$ pairing of neutrons in the NS core, and using realistic density profiles of the superfluid critical temperatures $T_{\rm c}(\rho)$. The theoretical cooling models of isolated middle-aged NSs can be divided into three main types. (I) {\it Low-mass}, {\it slowly cooling} NSs where the direct Urca process of neutrino emission is either forbidden or almost fully suppressed by the proton superfluidity. (II) {\it Medium-mass} NSs which show {\it moderate} cooling via the direct Urca process suppressed by the proton superfluidity. (III) {\it Massive} NSs which show {\it fast} cooling via the direct Urca process weakly suppressed by superfluidity. Confronting the theory with observations we treat RX J0822--43, PSR 1055--52 and RX J1856--3754 as slowly cooling NSs. To explain these sufficiently warm sources we need a density profile $T_{\rm c}(\rho)$ in the crust with a rather high and flat maximum and sharp wings. We treat 1E 1207--52, RX J0002+62, PSR 0656+14, Vela, and Geminga as moderately cooling NSs. We can determine their masses for a given model of proton superfluidity, $T_{\rm cp}(\rho)$, and the equation of state in the NS core. No rapidly cooling NS has been observed so far.Comment: 12 pages, 10 figures, Astron. Astrophys., submitte

Selection effects in the black hole-bulge relation and its evolution

We present an investigation of sample selection effects that influence the observed black hole - bulge relations and its evolution with redshift. We provide a common framework in which all kinds of selection effects on the BH-bulge relations can be investigated, but our main emphasis is on the consequences of using broad-line AGN and their host galaxies to search for evolution in the BH-bulge relation. We identified relevant sources of bias that were not discussed in the literature so far. A particularly important effect is caused by the fact that the active fraction among SMBHs varies considerably with BH mass, in the sense that high-mass BHs are less likely to be active than lower mass ones. In the connection with intrinsic scatter of the BH-bulge relation this effect implies a bias towards a low BH mass at given bulge property. This effect adds to the bias caused by working with luminosity or flux limited samples that were already discussed by others. A quantitative prediction of these biases requires (i) a realistic model of the sample selection function, and (ii) knowledge of relevant underlying distribution functions. For low-redshift AGN samples we can naturally reproduce the flattening of the relation observed in some studies. When extending our analysis to higher redshift samples we are clearly hampered by limited empirical constraints on the various relevant distribution functions. Using a best-guess approach for these distributions we estimate the expected magnitude of sample selection biases for a number of recent observational attempts to study the BH-bulge evolution. In no case do we find statistically significant evidence for an evolving BH-bulge relation. We suggest a possible practical approach to circumvent several of the most problematic issues connected with AGN selection; this could become a powerful diagnostic in future investigations (abridged).Comment: 20 pages, 20 figures, accepted for publication in A&

Seasonal, synoptic, and diurnal-scale variability of biogeochemical trace gases and O2 from a 300-m tall tower in central Siberia

We present first results from 19 months of semicontinuous concentration measurements of biogeochemical trace gases (CO2, CO, and CH4) and O2, measured at the Zotino Tall Tower Observatory (ZOTTO) in the boreal forest of central Siberia. We estimated CO2 and O2 seasonal cycle amplitudes of 26.6 ppm and 134 per meg, respectively. An observed west-east gradient of about -7 ppm (in July 2006) between Shetland Islands, Scotland, and ZOTTO reflects summertime continental uptake of CO2 and is consistent with regional modeling studies. We found the oceanic component of the O2 seasonal amplitude (Atmospheric Potential Oxygen, or APO) to be 51 per meg, significantly smaller than the 95 per meg observed at Shetlands, illustrating a strong attenuation of the oceanic O2 signal in the continental interior. Comparison with the Tracer Model 3 (TM3) atmospheric transport model showed good agreement with the observed phasing and seasonal amplitude in CO2; however, the model exhibited greater O2 (43 per meg, 32%) and smaller APO (9 per meg, 18%) amplitudes. This seeming inconsistency in model comparisons between O2 and APO appears to be the result of phasing differences in land and ocean signals observed at ZOTTO, where ocean signals have a significant lag. In the first 2 months of measurements on the fully constructed tower (November and December 2006), we observed several events with clear vertical concentration gradients in all measured species except CO. During “cold events” (below -30°C) in November 2006, we observed large vertical gradients in CO2 (up to 22 ppm), suggesting a strong local source. The same pattern was observed in CH4 concentrations for the same events. Diurnal vertical CO2 gradients in April to May 2007 gave estimates for average nighttime respiration fluxes of 0.04 ± 0.02 mol C m-2 d-1, consistent with earlier eddy covariance measurements in 1999–2000 in the vicinity of the tower

The first wave of pandemic influenza (H1N1) 2009 in Germany: From initiation to acceleration

<p>Abstract</p> <p>Background</p> <p>The first imported case of pandemic influenza (H1N1) 2009 in Germany was confirmed in April 2009. However, the first wave with measurable burden of disease started only in October 2009. The basic epidemiological and clinical characteristics of the pandemic were analysed in order to understand the course of the pandemic in Germany.</p> <p>Methods</p> <p>The analysis was based on data from the case-based, mandatory German surveillance system for infectious diseases. Cases notified between 27 April and 11 November 2009 and fulfilling the case definition were included in the study.</p> <p>Results</p> <p>Two time periods with distinct epidemiologic characteristics could be determined: 23,789 cases (44.1%) occurred during the initiation period (IP, week 18 to 41), and 30,179 (55.9%) during the acceleration period (AP, week 42 to 45). During IP, coinciding with school summer holidays, 61.1% of cases were travel-related and one death occurred. Strict containment efforts were performed until week 32. During AP the majority of cases (94.3%) was autochthonous, 12 deaths were reported. The main affected age group shifted from 15 to 19 years in IP to 10 to 14 years in AP (median age 19 versus 15 years; p < 0.001). The proportion of cases with underlying medical conditions increased from 4.7% to 6.9% (p < 0.001). Irrespective of the period, these cases were more likely to be hospitalised (OR = 3.6 [95% CI: 3.1; 4.3]) and to develop pneumonia (OR = 8.1 [95% CI: 6.1; 10.7]). Furthermore, young children (0 to 2 years) (OR = 2.8 [95% CI: 1.5; 5.2]) and persons with influenza-like illness (ILI, OR = 1.4 [95% CI: 1.0; 2.1]) had a higher risk to develop pneumonia compared to other age groups and individuals without ILI.</p> <p>Conclusion</p> <p>The epidemiological differences we could show between summer and autumn 2009 might have been influenced by the school summer holidays and containment efforts. The spread of disease did not result in change of risk groups or severity. Our results show that analyses of case-based information can advise future public health measures.</p

The Hydrogen-Poor Superluminous Supernovae from the Zwicky Transient Facility Phase-I Survey: I. Light Curves and Measurements

During the Zwicky Transient Facility (ZTF) Phase-I operation, 78 hydrogen-poor superluminous supernovae (SLSNe-I) were discovered in less than three years, making up the largest sample from a single survey. This paper (Paper I) presents the data, including the optical/ultraviolet light curves and classification spectra, while Paper II in this series will focus on the detailed analysis of the light curves and modeling. Our photometry is primarily taken by the ZTF in the $g,r,i$ bands, and with additional data from other ground-based facilities and Swift. The events of our sample cover a redshift range of $z = 0.06 - 0.67$, with a median and $1\sigma$ error (16\% and 84\% percentiles) $z_{\rm med} = 0.265^{+0.143}_{-0.135}$. The peak luminosity covers $-22.8\,{\rm mag} \leq M_{g,\rm peak} \leq -19.8$\,mag, with a median value of $-21.48^{+1.13}_{-0.61}$\,mag. Their light curves evolve slowly with the mean rest-frame rise time of $t_{\rm rise} = 41.9\pm17.8$\,days. The luminosity and time scale distributions suggest that low luminosity SLSNe-I with peak luminosity $\sim -20$\,mag or extremely fast rising events ($<10$\,days) exist but are rare. We confirm previous findings that slowly rising SLSNe-I also tend to fade slowly. The rest-frame color and temperature evolution show large scatters, suggesting that the SLSN-I population may have diverse spectral energy distributions. The peak rest-frame color shows a moderate correlation with the peak absolute magnitude, i.e. brighter SLSNe-I tend to have bluer colors. With optical and ultraviolet photometry, we construct bolometric luminosity and derive a bolometric correction relation generally applicable for converting $g,r$-band photometry to bolometric luminosity for SLSNe-I.Comment: 38 pages, 25 figures, Accepted by AP

Herbivore-induced terpenoid emission in Medicago truncatula: concerted action of jasmonate, ethylene and calcium signaling

Plant volatiles emitted by Medicago truncatula in response to feeding larvae of Spodoptera exigua are composed of a complex blend of terpenoids. The cDNAs of three terpene synthases (TPSs), which contribute to the blend of terpenoids, were cloned from M. truncatula. Their functional characterization proved MtTPS1 to be a β-caryophyllene synthase and MtTPS5 to be a multi-product sesquiterpene synthase. MtTPS3 encodes a bifunctional enzyme producing (E)-nerolidol and geranyllinalool (precursors of C11 and C16 homoterpenes) from different prenyl diphosphates serving as substrates. The addition of jasmonic acid (JA) induced expression of the TPS genes, but terpenoid emission was higher from plants treated with JA and the ethylene precursor 1-amino-cyclopropyl-1-carboxylic acid. Compared to infested wild-type M. truncatula plants, lower amounts of various sesquiterpenes and a C11–homoterpene were released from an ethylene-insensitive mutant skl. This difference coincided with lower transcript levels of MtTPS5 and of 1-deoxy-d-xylulose-5-phosphate synthase (MtDXS2) in the damaged skl leaves. Moreover, ethephon, an ethylene-releasing compound, modified the extent and mode of the herbivore-stimulated Ca2+ variations in the cytoplasm that is necessary for both JA and terpene biosynthesis. Thus, ethylene contributes to the herbivory-induced terpenoid biosynthesis at least twice: by modulating both early signaling events such as cytoplasmic Ca2+-influx and the downstream JA-dependent biosynthesis of terpenoids

Hepatocyte growth factor enhances death receptor-induced apoptosis by up-regulating DR5

<p>Abstract</p> <p>Background</p> <p>Hepatocyte growth factor (HGF) and its receptor c-MET are commonly expressed in malignant gliomas and embryonic neuroectodermal tumors including medulloblastoma and appear to play an important role in the growth and dissemination of these malignancies. Dependent on cell context and the involvement of specific downstream effectors, both pro- and anti-apoptotic effects of HGF have been reported.</p> <p>Methods</p> <p>Human medulloblastoma cells were treated with HGF for 24–72 hours followed by death receptor ligand TRAIL (Tumor necrosis factor-related apoptosis-inducing ligand) for 24 hours. Cell death was measured by MTT and Annexin-V/PI flow cytometric analysis. Changes in expression levels of targets of interest were measured by Northern blot analysis, quantitative reverse transcription-PCR, Western blot analysis as well as immunoprecipitation.</p> <p>Results</p> <p>In this study, we show that HGF promotes medulloblastoma cell death induced by TRAIL. TRAIL alone triggered apoptosis in DAOY cells and death was enhanced by pre-treating the cells with HGF for 24–72 h prior to the addition of TRAIL. HGF (100 ng/ml) enhanced TRAIL (10 ng/ml) induced cell death by 36% (<it>P </it>< 0.001). No cell death was associated with HGF alone. Treating cells with PHA-665752, a specific c-Met receptor tyrosine kinase inhibitor, significantly abrogated the enhancement of TRAIL-induced cell death by HGF, indicating that its death promoting effect requires activation of its canonical receptor tyrosine kinase. Cell death induced by TRAIL+HGF was predominately apoptotic involving both extrinsic and intrinsic pathways as evidenced by the increased activation of caspase-3, 8, 9. Promotion of apoptosis by HGF occurred via the increased expression of the death receptor DR5 and enhanced formation of death-inducing signal complexes (DISC).</p> <p>Conclusion</p> <p>Taken together, these and previous findings indicate that HGF:c-Met pathway either promotes or inhibits medulloblastoma cell death via pathway and context specific mechanisms.</p