2,780 research outputs found

    The 2005 - 2007 Bala (Ankara, central Turkey) earthquakes : a case study for strike-slip fault terminations

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    An intense seismic activity has been observed after the Bala (Ankara, NW central Turkey) earthquakes (30 July 2005: Mw=5.3, 20 December 2007: Mw=5.4, and 26 December 2007: Mw=5.3), continuing up to the present. The epicenters and the focal mechanism solutions of the earthquakes indicate that the right lateral strike-slip Afşar fault, trending N55-60°W, is responsible for the main shocks. The Afşar fault is thought to be the NW continuation of the Tuzgölü fault zone, which is one of the main neotectonic elements in central Anatolia. On the other hand, the aftershock distributions of the 2005 event have a NNE trend, and those of the 2007 event show a NW trending. Some focal mechanism solutions of the 2005 Bala earthquake aftershocks indicate normal and oblique normal faulting that corresponds to the NNE-trending Karakeçili fault. It seems that seismic activation of the NNE-trending Karakeçili fault was triggered by the 2005 main shock (Mw=5.3) that occurred on the NW-trending right lateral strike-slip Afşar fault. The overall neotectonic framework is that the northwestern edge of the Tuzgölü fault zone, represented by the Afşar fault in Bala, terminates in an extensional system represented by the oblique-slip Karakeçili faul

    Improved Ambient Pressure Pyroelectric Ion Source

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    The detection of volatile vapors of unknown species in a complex field environment is required in many different applications. Mass spectroscopic techniques require subsystems including an ionization unit and sample transport mechanism. All of these subsystems must have low mass, small volume, low power, and be rugged. A volatile molecular detector, an ambient pressure pyroelectric ion source (APPIS) that met these requirements, was recently reported by Caltech researchers to be used in in situ environments

    Microstructural characterization and simulation of damage for geared sheet components

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    The evolution of damage in geared components manufactured from steel sheets was investigated, to analyse the influence of damage caused by the sheet-bulk-metal forming. Due to the inhomogeneous and multi-axial deformation in the investigated parts, different aspects such as the location-dependent shape and size of voids are analysed by means of various microscopic methods. In particular, a method to characterize the state of damage evolution, i. e. void nucleation, growth and coalescence using scanning electron microscopy (SEM) is applied. The investigations reveal a strong dependence of the void area fraction, shape of voids and thus damage evolution on the loading mode. The microstructural analysis is complemented with FEM simulations using material models which consider the characteristics of the void evolution. © Published under licence by IOP Publishing Ltd

    Resuscitation and quantification of stressed Escherichia coli K12 NCTC8797 in water samples

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    The aim of this study was to investigate the impact on numbers of using different media for the enumeration of Escherichia coli subjected to stress, and to evaluate the use of different resuscitation methods on bacterial numbers. E. coli was subjected to heat stress by exposure to 55 °C for 1 h or to light-induced oxidative stress by exposure to artificial light for up to 8 h in the presence of methylene blue. In both cases, the bacterial counts on selective media were below the limits of detection whereas on non-selective media colonies were still produced. After resuscitation in non-selective media, using a multi-well MPN resuscitation method or resuscitation on membrane filters, the bacterial counts on selective media matched those on non-selective media. Heat and light stress can affect the ability of E. coli to grow on selective media essential for the enumeration as indicator bacteria. A resuscitation method is essential for the recovery of these stressed bacteria in order to avoid underestimation of indicator bacteria numbers in water. There was no difference in resuscitation efficiency using the membrane filter and multi-well MPN methods. This study emphasises the need to use a resuscitation method if the numbers of indicator bacteria in water samples are not to be underestimated. False-negative results in the analysis of drinking water or natural bathing waters could have profound health effects

    Medium-resolution studies of extreme-ultraviolet emission from CO by electron impact

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    We report medium-resolution (0.025 nm full width at half maximum (FWHM)) electron impact-induced emission spectra of CO for 20, 100, and 200 eV impact energies. The emission spectra correspond to the extreme ultraviolet transitions from the B (sup 1)Sigma(sup +)(0), and E (sup 1)Pi(0) vibronic states to the X (sup 1)Sigma(sup +)(0) ground state. The present measurements are carried out at 20 times higher spectral resolution (to separate the many blended components) compared to our previous measurements, which were at a spectral resolution of 0.5 nm FWHM. The emission cross sections corresponding to the B (sup 1)Sigma(sup +)(0) yields X (sup 1)Sigma(sup +)(0), C (sup 1)Sigma(sup +)(0) yields X (sup 1)Sigma(sup +)(0), and E (sup 1)Pi(0) yields X (sup 1)Sigma(sup +)(0) resonance transitions were measured. In addition, excitation functions (0-1 keV) extending well into the Born region have been measured for the strong transitions (B (sup 1)Sigma(sup +)(0) yields X (sup 1)Sigma(sup +)(0) and C (sup 1)Sigma(sup +)(0)) and oscillator strengths have been determined, using a modified Born approximation analytic fit to the measured excitation function

    Dynamic proteomic profiling of extra-embryonic endoderm differentiation in mouse embryonic stem cells

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    During mammalian pre-implantation development, the cells of the blastocyst’s inner cell mass differentiate into the epiblast and primitive endoderm lineages, which give rise to the fetus and extra-embryonic tissues, respectively. Extra-embryonic endoderm differentiation can be modeled in vitro by induced expression of GATA transcription factors in mouse embryonic stem cells. Here we use this GATA-inducible system to quantitatively monitor the dynamics of global proteomic changes during the early stages of this differentiation event and also investigate the fully differentiated phenotype, as represented by embryo-derived extra-embryonic endoderm (XEN) cells. Using mass spectrometry-based quantitative proteomic profiling with multivariate data analysis tools, we reproducibly quantified 2,336 proteins across three biological replicates and have identified clusters of proteins characterized by distinct, dynamic temporal abundance profiles. We first used this approach to highlight novel marker candidates of the pluripotent state and extra-embryonic endoderm differentiation. Through functional annotation enrichment analysis, we have shown that the downregulation of chromatin-modifying enzymes, the re-organization of membrane trafficking machinery and the breakdown of cell-cell adhesion are successive steps of the extra-embryonic differentiation process. Thus, applying a range of sophisticated clustering approaches to a time-resolved proteomic dataset has allowed the elucidation of complex biological processes which characterize stem cell differentiation and could establish a general paradigm for the investigation of these processes.This work was supported by the European Union 7th Framework Program (PRIME-XS project grant number 262067 to K.S.L., L.G and C.M.M), the Biotechnology and Biological Sciences Research Council (BBSRC grant number BB/L002817/1 to K.S.L and L.G.), as well as a HFSP grant (RGP0029/2010) and a European Research Council (ERC) Advanced Investigator grant to A.M.A.. C.S was supported by an EMBO long term fellowship and a Marie Curie IEF. L.T.Y.C. and K.K.N. were supported by the Medical Research Council (MRC, UK, MC_UP_1202/9) and the March of Dimes Foundation (FY11-436). We also thank Professor Steve Oliver and Dr. A.K.Hadjantonakis for helpful discussions and advice.This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1002/stem.206

    Dynamic Proteomic Profiling of Extra-Embryonic Endoderm Differentiation in Mouse Embryonic Stem Cells.

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    During mammalian preimplantation development, the cells of the blastocyst's inner cell mass differentiate into the epiblast and primitive endoderm lineages, which give rise to the fetus and extra-embryonic tissues, respectively. Extra-embryonic endoderm (XEN) differentiation can be modeled in vitro by induced expression of GATA transcription factors in mouse embryonic stem cells. Here, we use this GATA-inducible system to quantitatively monitor the dynamics of global proteomic changes during the early stages of this differentiation event and also investigate the fully differentiated phenotype, as represented by embryo-derived XEN cells. Using mass spectrometry-based quantitative proteomic profiling with multivariate data analysis tools, we reproducibly quantified 2,336 proteins across three biological replicates and have identified clusters of proteins characterized by distinct, dynamic temporal abundance profiles. We first used this approach to highlight novel marker candidates of the pluripotent state and XEN differentiation. Through functional annotation enrichment analysis, we have shown that the downregulation of chromatin-modifying enzymes, the reorganization of membrane trafficking machinery, and the breakdown of cell-cell adhesion are successive steps of the extra-embryonic differentiation process. Thus, applying a range of sophisticated clustering approaches to a time-resolved proteomic dataset has allowed the elucidation of complex biological processes which characterize stem cell differentiation and could establish a general paradigm for the investigation of these processes.This work was supported by the European Union 7th Framework Program (PRIME-XS project grant number 262067 to K.S.L., L.G and C.M.M), the Biotechnology and Biological Sciences Research Council (BBSRC grant number BB/L002817/1 to K.S.L and L.G.), as well as a HFSP grant (RGP0029/2010) and a European Research Council (ERC) Advanced Investigator grant to A.M.A.. C.S was supported by an EMBO long term fellowship and a Marie Curie IEF. L.T.Y.C. and K.K.N. were supported by the Medical Research Council (MRC, UK, MC_UP_1202/9) and the March of Dimes Foundation (FY11-436). We also thank Professor Steve Oliver and Dr. A.K.Hadjantonakis for helpful discussions and advice.This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1002/stem.206

    Tourism, Environment and Energy: An Analysis for China

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    International tourism as a cause of global warming is a controversial and topical issue. Here, we use the novel Morlet Wavelet time-frequency approach to gain a deeper insight into the dynamic nexus between tourism, renewable energy utilization, energy utilization and carbon dioxide emissions for China using annual data over the era 1974-2016. The techniques we use include Continuous Wavelet power spectrum, the Wavelet Coherency, and the Partial and the Multiple Wavelet Coherence for time-frequency decomposition that can capture local oscillatory components in time series. Our findings support the hypothesis that tourism can cause increased energy utilization and carbon dioxide emissions in China, which challenges the sustainable tourism development goal. However, on the positive side, the relationship between tourism and renewable energy utilization is shown to facilitate reduced environmental degradation in the medium-long run
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