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  • Artikel  (143.386)
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  • 1
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    RETRACTED ARTICLE: Detection and replication of epistasis influencing transcription in humans (2014)
    Springer Nature
    Details
    Publikationsdatum: 2014-02-26
    Print ISSN: 0028-0836
    Digitale ISSN: 1476-4687
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Publiziert von Springer Nature
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  • 2
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    Differentiating flavors of the Indian Ocean Dipole using dominant modes in tropical Indian Ocean rainfall (2014)
    Wiley
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    Publikationsdatum: 2014-12-07
    Beschreibung: Phase-locked to austral winter and spring, canonical positive Indian Ocean Dipoles (pIODs) generally peak in spring. In recent decades, there has been an increase in unseasonable pIODs which, different from canonical pIODs, peak and decay by September. Distinguishing unseasonable pIODs from canonical pIODs is important, as conditions leading to more frequent unseasonable events are projected to persist in a warming climate. Here using superimposition of the first two seasonally evolving dominant modes of tropical Indian Ocean rainfall variability, we differentiate these types of pIODs. The first mode reflects characteristics of canonical pIODs, in which anomalies intensify with seasonal evolution. However, the second mode, with cool and dry anomalies extending from the eastern pole, reverses from winter to spring, signifying the demise of unseasonable pIODs. Processes embedded in the second mode reflect timing of propagation in equatorial Kelvin waves, and their relative importance to the first mode, in generating different pIODs.
    Print ISSN: 0094-8276
    Digitale ISSN: 1944-8007
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley im Namen von American Geophysical Union (AGU).
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  • 3
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    The Oslo temperature series 1837–2012: homogeneity testing and temperature analysis (2014)
    Wiley
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    Publikationsdatum: 2014-12-07
    Beschreibung: ABSTRACT A 175 years long homogenized composite record of monthly mean temperatures is presented for Oslo, the capital of Norway. The early raw data have been digitised and quality controlled, and monthly means have been calculated. Some early original observations carried out in a Wild screen (1877–1936) were found to be spuriously high because of inappropriate sheltering from sunlight. These spurious temperatures were not used in the composite record, but alternative temperatures measured (1837–1933) by thermometers placed outside windows at the Astronomical Observatory were used instead. No inhomogeneity was detected in the latter series after adding an instrument correction of +0.3 °C, but the start year of the correction remains uncertain. The more recent part of the composite record used the long-term series (1937 to present) from Blindern in Oslo, the premises of The Norwegian Meteorological Institute. Two small inhomogeneities were detected in the Blindern series, possibly caused by a weak urban heat island effect or growing/cutting of trees. The study revealed that the annual mean temperature has increased by 1.5 °C in the period 1838–2012. The most pronounced increase in annual temperature occurred during the last 50 years, and in the early 20th century that ended with a local maximum in the 1930s. The temperature has increased significantly in all seasons; however, the temperature increase in summer was less than a half of that in winter and spring, which were the seasons with largest increase. In addition the monthly mean temperature of the coldest month in each year has increased two times faster than the warmest one. The most significant temperature variations were associated to ∼ 5-year time scales in its early part, but since 1930 and up to present, the dominant time scales were 10–20 years.
    Print ISSN: 0899-8418
    Digitale ISSN: 1097-0088
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley
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  • 4
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    Anomalous critical fields in quantum critical superconductors (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-07
    Beschreibung: Article Superconductivity in the iron pnictides is believed to be related to quantum critical fluctuations. Putzke et al. observe unexpected anomalies in the critical fields of BaFe 2 (As 1−x P x ) 2 that emerge close to its magnetic critical point, which they argue is a generic feature of quantum critical superconductivity. Nature Communications doi: 10.1038/ncomms6679 Authors: C. Putzke, P. Walmsley, J. D. Fletcher, L. Malone, D. Vignolles, C. Proust, S. Badoux, P. See, H. E. Beere, D. A. Ritchie, S. Kasahara, Y. Mizukami, T. Shibauchi, Y. Matsuda, A. Carrington
    Digitale ISSN: 2041-1723
    Thema: Biologie , Chemie und Pharmazie , Allgemeine Naturwissenschaft , Physik
    Publiziert von Springer Nature
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  • 5
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    A catalogue of 2D photometric decompositions in the SDSS-DR7 spectroscopic main galaxy sample: preferred models and systematics (2014)
    Oxford University Press
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    Publikationsdatum: 2014-12-12
    Beschreibung: We present a catalogue of 2D, point spread function-corrected de Vacouleurs, Sérsic, de Vacouleurs+Exponential, and Sérsic+Exponential fits of ~7 x 10 5 spectroscopically selected galaxies drawn from the Sloan Digital Sky Survey (SDSS) Data Release 7. Fits are performed for the SDSS r band utilizing the fitting routine galfit and analysis pipeline pymorph . We compare these fits to prior catalogues. Fits are analysed using a physically motivated flagging system. The flags suggest that more than 90 per cent of two-component fits can be used for analysis. We show that the fits follow the expected behaviour for early and late galaxy types. The catalogues provide a robust set of structural and photometric parameters for future galaxy studies. We show that some biases remain in the measurements, e.g. the presence of bars significantly affect the bulge measurements although the bulge ellipticity may be used to separate barred and non-barred galaxies, and about 15 per cent of bulges of two-component fits are also affected by resolution. The catalogues are available in electronic format. We also provide an interface for generating postage stamp images of the 2D model and residual as well as the 1D profile. These images can be generated for a user-uploaded list of galaxies on demand.
    Print ISSN: 0035-8711
    Digitale ISSN: 1365-2966
    Thema: Physik
    Publiziert von Oxford University Press
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  • 6
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    microTSS: accurate microRNA transcription start site identification reveals a significant number of divergent pri-miRNAs (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-12
    Beschreibung: Article microRNAs are short non-coding RNAs that post-transcriptionally regulate gene expression for which the identification of promoter and primary transcripts (pri-miRNAs) has been difficult. Here the authors describe microTSS, an algorithm that supports the precise identification of intergenic pri-miRNA transcription start sites. Nature Communications doi: 10.1038/ncomms6700 Authors: Georgios Georgakilas, Ioannis S. Vlachos, Maria D. Paraskevopoulou, Peter Yang, Yuhong Zhang, Aris N. Economides, Artemis G. Hatzigeorgiou
    Digitale ISSN: 2041-1723
    Thema: Biologie , Chemie und Pharmazie , Allgemeine Naturwissenschaft , Physik
    Publiziert von Springer Nature
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  • 7
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    Transcriptome analysis reveals dysregulation of innate immune response genes and neuronal activity-dependent genes in autism (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-12
    Beschreibung: Article Autism spectrum disorder (ASD) is a common, highly heritable neurodevelopmental condition characterized by marked genetic heterogeneity. In this study, the authors use RNA sequencing analyses to characterize differences in the transcriptome between autistic and typically developing brains. Nature Communications doi: 10.1038/ncomms6748 Authors: Simone Gupta, Shannon E. Ellis, Foram N. Ashar, Anna Moes, Joel S. Bader, Jianan Zhan, Andrew B. West, Dan E. Arking
    Digitale ISSN: 2041-1723
    Thema: Biologie , Chemie und Pharmazie , Allgemeine Naturwissenschaft , Physik
    Publiziert von Springer Nature
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  • 8
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    All-organic optoelectronic sensor for pulse oximetry (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-12
    Beschreibung: Article Pulse oximetry is a non-invasive means for measuring blood oxygen saturation and pulse rate, with typical sensors based on rigid electronics. Here, the authors develop a pulse oximeter based solely on organic materials, allowing flexible devices and hence increasing the potential sensing locations on the body. Nature Communications doi: 10.1038/ncomms6745 Authors: Claire M. Lochner, Yasser Khan, Adrien Pierre, Ana C. Arias
    Digitale ISSN: 2041-1723
    Thema: Biologie , Chemie und Pharmazie , Allgemeine Naturwissenschaft , Physik
    Publiziert von Springer Nature
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  • 9
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    Laser-induced porous graphene films from commercial polymers (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-12
    Beschreibung: Article The straightforward and scalable synthesis and patterning of graphene-based nanomaterials remains a technological challenge. Here, the authors use a CO 2 infrared laser, under ambient conditions, to directly produce and pattern porous graphene films with three-dimensional networks from commercial polymer films. Nature Communications doi: 10.1038/ncomms6714 Authors: Jian Lin, Zhiwei Peng, Yuanyue Liu, Francisco Ruiz-Zepeda, Ruquan Ye, Errol L. G. Samuel, Miguel Jose Yacaman, Boris I. Yakobson, James M. Tour
    Digitale ISSN: 2041-1723
    Thema: Biologie , Chemie und Pharmazie , Allgemeine Naturwissenschaft , Physik
    Publiziert von Springer Nature
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  • 10
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    Electrically tunable nonlinear plasmonics in graphene nanoislands (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-13
    Beschreibung: Article Plasmons in metallic nanostructures provide light enhancement that amplifies their nonlinear optical response. This study shows that graphene nanoislands also give rise to an amplified nonlinear polarizability that can be tuned electrically to surpass those of other nonlinear media by orders of magnitude. Nature Communications doi: 10.1038/ncomms6725 Authors: Joel D. Cox, F. Javier García de Abajo
    Digitale ISSN: 2041-1723
    Thema: Biologie , Chemie und Pharmazie , Allgemeine Naturwissenschaft , Physik
    Publiziert von Springer Nature
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  • 11
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    Structural insights into 5′ flap DNA unwinding and incision by the human FAN1 dimer (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-13
    Beschreibung: Article FAN1 is a structure-specific nuclease that plays a major role in eliminating highly cytotoxic interstrand DNA crosslinks. Here, Zhao et al . present several crystal structures of FAN1 in complex with DNA substrates and biochemical analyses that establish how FAN1 functions to resolve interstrand DNA crosslinks. Nature Communications doi: 10.1038/ncomms6726 Authors: Qi Zhao, Xiaoyu Xue, Simonne Longerich, Patrick Sung, Yong Xiong
    Digitale ISSN: 2041-1723
    Thema: Biologie , Chemie und Pharmazie , Allgemeine Naturwissenschaft , Physik
    Publiziert von Springer Nature
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  • 12
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    The H I-dominated low-surface-brightness galaxy KKR 17 (2014)
    Oxford University Press
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    Publikationsdatum: 2014-12-13
    Beschreibung: We present new narrow-band (Hα and [O  iii ]) images and optical spectrophotometry of H  ii regions for a gas-rich low-surface-brightness irregular galaxy, KKR 17. The central surface brightness of the galaxy is μ 0 ( B ) = 24.15 ± 0.03 mag s –2 . The galaxy was detected by the Arecibo Legacy Fast ALFA survey (ALFALFA). Its mass is dominated by neutral hydrogen (H  i ) gas. In contrast, both the stellar masses of the bright H  ii and diffuse stellar regions are small. In addition, the fit to the spectral energy distribution to each region shows the stellar populations of H  ii and diffuse regions are different. The bright H  ii region contains a large fraction of O-type stars, revealing recent strong star formation, whereas the diffuse region is dominated by median age stars with a typical age of ~600 Myr. Using McGaugh's abundance model, we found that the average metallicity of KKR 17 is 12 + (O/H) = 8.0 ± 0.1. The star-formation rate of KKR 17 is 0.21 ± 0.04 M  yr –1 , which is ~1/5 of our Milky Way's. Based on the analysis results for young stellar clusters in the H  ii region, the bright H  ii region has two sub-components with different velocities and metallicities. This may be caused by the outflow of massive stars or merging events. However, the mechanism triggering star formation in the H  ii region is still uncertain.
    Print ISSN: 0035-8711
    Digitale ISSN: 1365-2966
    Thema: Physik
    Publiziert von Oxford University Press
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  • 13
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    A multiwavelength study of the M dwarf binary YY Geminorum (2014)
    Oxford University Press
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    Publikationsdatum: 2014-12-13
    Beschreibung: We review the results of the 1988 multiwavelength campaign on the late-type eclipsing binary YY Geminorum. Observations include: broad-band optical and near-infrared photometry, simultaneous optical and ultraviolet ( IUE ) spectroscopy, X-ray ( Ginga ) and radio (VLA) data. From models fitted to the optical light curves, fundamental physical parameters have been determined together with evidence for transient maculations (spots) located near quadrature longitudes and intermediate latitudes. Eclipses were observed at optical, ultraviolet and radio wavelengths. Significant drops in 6 cm radio emission near the phases of both primary and secondary eclipse indicate relatively compact radio emitting volumes that may lie between the binary components. IUE observations during secondary eclipse are indicative of a uniform chromosphere saturated with Mg  ii emission and an extended volume of Lyα emission. Profile fitting of high-dispersion Hα spectra confirms the chromospheric saturation and indicates significant Hα opacity to heights of a few per cent of the photospheric radius. There is evidence for an enhanced Hα emission region visible near phase 0.25–0.35 which may be associated with a large spot on the primary and with two small optical flares which were also observed at other wavelengths: one in microwave radiation and the other in X-rays. For both flares, L X / L opt is consistent with energy release in closed magnetic structures.
    Print ISSN: 0035-8711
    Digitale ISSN: 1365-2966
    Thema: Physik
    Publiziert von Oxford University Press
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  • 14
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    Spartan deficiency causes genomic instability and progeroid phenotypes (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-13
    Beschreibung: Article Spartan/DVC1 is a translesion synthesis regulator with important roles in cellular DNA damage tolerance. Here, the authors report that Spartan is essential for DNA lesion bypass and that Spartan insufficiency in mice causes chromosomal instability, cellular senescence and early onset of age-related phenotypes. Nature Communications doi: 10.1038/ncomms6744 Authors: Reeja S. Maskey, Myoung Shin Kim, Darren J. Baker, Bennett Childs, Liviu A. Malureanu, Karthik B. Jeganathan, Yuka Machida, Jan M. van Deursen, Yuichi J. Machida
    Digitale ISSN: 2041-1723
    Thema: Biologie , Chemie und Pharmazie , Allgemeine Naturwissenschaft , Physik
    Publiziert von Springer Nature
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  • 15
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    Geochemistry of silicate-rich rocks can curtail spreading of carbon dioxide in subsurface aquifers (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-13
    Beschreibung: Article Carbon sequestration will be vital in mitigating future climate change, and understanding how CO 2 behaves in aquifers is important for developing technologies. Here, the authors suggest that silicate-rich rocks inhibit the transport of CO 2 , which may have consequences for future engineered storage facilities. Nature Communications doi: 10.1038/ncomms6743 Authors: S. S. S. Cardoso, J. T. H. Andres
    Digitale ISSN: 2041-1723
    Thema: Biologie , Chemie und Pharmazie , Allgemeine Naturwissenschaft , Physik
    Publiziert von Springer Nature
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  • 16
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    Sound Pressure Level Gain in an Acoustic Metamaterial Cavity (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-12
    Beschreibung: The inherent attenuation of a homogeneous viscous medium limits radiation propagation, thereby restricting the use of many high-frequency acoustic devices to only short-range applications. Here, we design and experimentally demonstrate an acoustic metamaterial localization cavity which is used for sound pressure level (SPL) gain using double coiled up space like structures thereby increasing the range of detection. This unique behavior occurs within a subwavelength cavity that is 1/10th of the wavelength of the incident acoustic wave, which provides up to a 13 dB SPL gain. We show that the amplification results from the Fabry-Perot resonance of the cavity, which has a simultaneously high effective refractive index and effective impedance. We also experimentally verify the SPL amplification in an underwater environment at higher frequencies using a sample with an identical unit cell size. The versatile scalability of the design shows promising applications in many areas, especially in acoustic imaging and underwater communication. Scientific Reports 4 doi: 10.1038/srep07421
    Digitale ISSN: 2045-2322
    Thema: Allgemeine Naturwissenschaft
    Publiziert von Springer Nature
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  • 17
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    Azithromycin suppresses CD4+ T-cell activation by direct modulation of mTOR activity (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-12
    Beschreibung: Advanced macrolides, such as azithromycin (AZM) or clarithromycin (CLM), are antibiotics with immunomodulatory properties. Here we have sought to evaluate their in vitro influence on the activation of CD4+ T-cells. Isolated CD4+ T-cells were stimulated with agonistic anti-CD3/anti-CD28 monoclonal antibodies in the presence of 0.6 mg/L, 2.5 mg/L, 10 mg/L or 40 mg/L AZM or CLM. Cell proliferation, cytokine level in supernatants and cell viability was assessed. Intracellular signaling pathways were evaluated using reporter cell lines, FACS analysis, immunoblotting and in vitro kinase assays. AZM inhibited cell proliferation rate and cytokine secretion of CD4+ T-cells in a dose-dependent manner. Similarly, high concentrations of CLM (40 mg/L) also suppressed these T-cell functions. Analysis of molecular signaling pathways revealed that exposure to AZM reduced the phosphorylation of the S6 ribosomal protein, a downstream target of mTOR. This effect was also observed at 40 mg/L CLM. In vitro kinase studies using recombinant mTOR showed that AZM inhibited mTOR activity. In contrast to rapamycin, this inhibition was independent of FKBP12. We show for the first time that AZM and to a lesser extent CLM act as immunosuppressive agents on CD4+ T-cells by inhibiting mTOR activity. Our results might have implications for the clinical use of macrolides. Scientific Reports 4 doi: 10.1038/srep07438
    Digitale ISSN: 2045-2322
    Thema: Allgemeine Naturwissenschaft
    Publiziert von Springer Nature
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  • 18
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    A Low-Noise Solid-State Nanopore Platform Based on a Highly Insulating Substrate (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-13
    Beschreibung: A solid-state nanopore platform with a low noise level and sufficient sensitivity to discriminate single-strand DNA (ssDNA) homopolymers of poly-A40 and poly-T40 using ionic current blockade sensing is proposed and demonstrated. The key features of this platform are (a) highly insulating dielectric substrates that are used to mitigate the effect of parasitic capacitance elements, which decrease the ionic current RMS noise level to sub-10 pA and (b) ultra-thin silicon nitride membranes with a physical thickness of 5 nm (an effective thickness of 2.4 nm estimated from the ionic current) are used to maximize the signal-to-noise ratio and the spatial depth resolution. The utilization of an ultra-thin membrane and a nanopore diameter as small as 1.5 nm allow the successful discrimination of 40 nucleotide ssDNA poly-A40 and poly-T40. Overall, we demonstrate that this platform overcomes several critical limitations of solid-state nanopores and opens the door to a wide range of applications in single-molecule-based detection and analysis. Scientific Reports 4 doi: 10.1038/srep07448
    Digitale ISSN: 2045-2322
    Thema: Allgemeine Naturwissenschaft
    Publiziert von Springer Nature
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  • 19
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    Do good actions inspire good actions in others? (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-13
    Beschreibung: Actions such as sharing food and cooperating to reach a common goal have played a fundamental role in the evolution of human societies. Despite the importance of such good actions, little is known about if and how they can spread from person to person to person. For instance, does being recipient of an altruistic act increase your probability of being cooperative with a third party? We have conducted an experiment on Amazon Mechanical Turk to test this mechanism using economic games. We have measured willingness to be cooperative through a standard Prisoner's dilemma and willingness to act altruistically using a binary Dictator game. In the baseline treatments, the endowments needed to play were given by the experimenters, as usual; in the control treatments, they came from a good action made by someone else. Across four different comparisons and a total of 572 subjects, we have never found a significant increase of cooperation or altruism when the endowment came from a good action. We conclude that good actions do not necessarily inspire good actions in others. While this is consistent with the theoretical prediction, it challenges the majority of other experimental studies. Scientific Reports 4 doi: 10.1038/srep07470
    Digitale ISSN: 2045-2322
    Thema: Allgemeine Naturwissenschaft
    Publiziert von Springer Nature
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  • 20
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    Two functional loci in the promoter of EPAS1 gene involved in high-altitude adaptation of Tibetans (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-13
    Beschreibung: EPAS1 involves in the hypoxic response and is suggested to be responsible for the genetic adaptation of high-altitude hypoxia in Tibetans. However, the detailed molecular mechanism remains unknown. In this study, a single nucleotide polymorphism rs56721780:G〉C and an insertion/deletion (indel) polymorphism −742 indel in the promoter region showed divergence between Tibetans and non-Tibetan lowlanders. rs56721780:G〉C regulated the transcription of EPAS1 by IKAROS family zinc finger 1 (IKZF1), which was identified as a new transcriptional repressor for EPAS1 gene. It demonstrated that the C allele of rs56721780:G〉C decreased the binding of IKZF1, leading to the attenuated transcriptional repression of EPAS1 gene. The insertion at −742 indel provided a new binding site for Sp1 and was related to the activation of EPAS1 promoter. Further functional analysis revealed that lysyl oxidase (LOX) gene, which was reported to be responsible for extracellular matrix protein cross-linking of amnion previously, was a direct target of EPAS1. The CC genotype at rs56721780:G〉C and the insertion genotype at −742 indel were found associated with higher EPAS1 and LOX expression levels in amnion, as well as higher birth weight of Tibetan newborns, suggesting that EPAS1 gene might play important roles in the development of amnion, fetus growth and high-altitude adaptation of Tibetans. Scientific Reports 4 doi: 10.1038/srep07465
    Digitale ISSN: 2045-2322
    Thema: Allgemeine Naturwissenschaft
    Publiziert von Springer Nature
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  • 21
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    Effects of reciprocity on random walks in weighted networks (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-13
    Beschreibung: It has been recently reported that the reciprocity of real-life weighted networks is very pronounced, however its impact on dynamical processes is poorly understood. In this paper, we study random walks in a scale-free directed weighted network with a trap at the central hub node, where the weight of each directed edge is dominated by a parameter controlling the extent of network reciprocity. We derive two expressions for the mean first passage time (MFPT) to the trap, by using two different techniques, the results of which agree well with each other. We also analytically determine all the eigenvalues as well as their multiplicities for the fundamental matrix of the dynamical process, and show that the largest eigenvalue has an identical dominant scaling as that of the MFPT.We find that the weight parameter has a substantial effect on the MFPT, which behaves as a power-law function of the system size with the power exponent dependent on the parameter, signaling the crucial role of reciprocity in random walks occurring in weighted networks. Scientific Reports 4 doi: 10.1038/srep07460
    Digitale ISSN: 2045-2322
    Thema: Allgemeine Naturwissenschaft
    Publiziert von Springer Nature
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  • 22
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    Survival analysis of infected mice reveals pathogenic variations in the genome of avian H1N1 viruses (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-13
    Beschreibung: Most influenza pandemics have been caused by H1N1 viruses of purely or partially avian origin. Here, using Cox proportional hazard model, we attempt to identify the genetic variations in the whole genome of wild-type North American avian H1N1 influenza A viruses that are associated with their virulence in mice by residue variations, host origins of virus (Anseriformes-ducks or Charadriiformes-shorebirds), and host-residue interactions. In addition, through structural modeling, we predicted that several polymorphic sites associated with pathogenicity were located in structurally important sites, especially in the polymerase complex and NS genes. Our study introduces a new approach to identify pathogenic variations in wild-type viruses circulating in the natural reservoirs and ultimately to understand their infectious risks to humans as part of risk assessment efforts towards the emergence of future pandemic strains. Scientific Reports 4 doi: 10.1038/srep07455
    Digitale ISSN: 2045-2322
    Thema: Allgemeine Naturwissenschaft
    Publiziert von Springer Nature
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    Inhibition of CO poisoning on Pt catalyst coupled with the reduction of toxic hexavalent chromium in a dual-functional fuel cell (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-13
    Beschreibung: We propose a method to enhance the fuel cell efficiency with the simultaneous removal of toxic heavy metal ions. Carbon monoxide (CO), an intermediate of methanol oxidation that is primarily responsible for Pt catalyst deactivation, can be used as an in-situ reducing agent for hexavalent chromium (Cr (VI)) with reactivating the CO-poisoned Pt catalyst. Using electro-oxidation measurements, the oxidation of adsorbed CO molecules coupled with the concurrent conversion of Cr (VI) to Cr (III) was confirmed. This concept was also successfully applied to a methanol fuel cell to enhance its performance efficiency and to remove toxic Cr (VI) at the same time. Scientific Reports 4 doi: 10.1038/srep07450
    Digitale ISSN: 2045-2322
    Thema: Allgemeine Naturwissenschaft
    Publiziert von Springer Nature
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    Taurine in drinking water recovers learning and memory in the adult APP/PS1 mouse model of Alzheimer's disease (2014)
    Springer Nature
    Details
    Publikationsdatum: 2014-12-13
    Beschreibung: Alzheimer's disease (AD) is a lethal progressive neurological disorder affecting the memory. Recently, US Food and Drug Administration mitigated the standard for drug approval, allowing symptomatic drugs that only improve cognitive deficits to be allowed to accelerate on to clinical trials. Our study focuses on taurine, an endogenous amino acid found in high concentrations in humans. It has demonstrated neuroprotective properties against many forms of dementia. In this study, we assessed cognitively enhancing property of taurine in transgenic mouse model of AD. We orally administered taurine via drinking water to adult APP/PS1 transgenic mouse model for 6 weeks. Taurine treatment rescued cognitive deficits in APP/PS1 mice up to the age-matching wild-type mice in Y-maze and passive avoidance tests without modifying the behaviours of cognitively normal mice. In the cortex of APP/PS1 mice, taurine slightly decreased insoluble fraction of Aβ. While the exact mechanism of taurine in AD has not yet been ascertained, our results suggest that taurine can aid cognitive impairment and may inhibit Aβ-related damages. Scientific Reports 4 doi: 10.1038/srep07467
    Digitale ISSN: 2045-2322
    Thema: Allgemeine Naturwissenschaft
    Publiziert von Springer Nature
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    Liquid but Durable: Molecular Dynamics Simulations Explain the Unique Properties of Archaeal-Like Membranes (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-13
    Beschreibung: Archaeal plasma membranes appear to be extremely durable and almost impermeable to water and ions, in contrast to the membranes of Bacteria and Eucaryota. Additionally, they remain liquid within a temperature range of 0–100°C. These are the properties that have most likely determined the evolutionary fate of Archaea, and it may be possible for bionanotechnology to adopt these from nature. In this work, we use molecular dynamics simulations to assess at the atomistic level the structure and dynamics of a series of model archaeal membranes with lipids that have tetraether chemical nature and “branched” hydrophobic tails. We conclude that the branched structure defines dense packing and low water permeability of archaeal-like membranes, while at the same time ensuring a liquid-crystalline state, which is vital for living cells. This makes tetraether lipid systems promising in bionanotechnology and material science, namely for design of new and unique membrane nanosystems. Scientific Reports 4 doi: 10.1038/srep07462
    Digitale ISSN: 2045-2322
    Thema: Allgemeine Naturwissenschaft
    Publiziert von Springer Nature
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    CORRIGENDUM: Parametric spectro-temporal analyzer (PASTA) for real-time optical spectrum observation (2014)
    Springer Nature
    Details
    Publikationsdatum: 2014-12-13
    Beschreibung: Scientific Reports 4 doi: 10.1038/srep05692
    Digitale ISSN: 2045-2322
    Thema: Allgemeine Naturwissenschaft
    Publiziert von Springer Nature
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    Genome dynamics and evolution of Salmonella Typhi strains from the typhoid-endemic zones (2014)
    Springer Nature
    Details
    Publikationsdatum: 2014-12-13
    Beschreibung: Typhoid fever poses significant burden on healthcare systems in Southeast Asia and other endemic countries. Several epidemiological and genomic studies have attributed pseudogenisation to be the major driving force for the evolution of Salmonella Typhi although its real potential remains elusive. In the present study, we analyzed genomes of S. Typhi from different parts of Southeast Asia and Oceania, comprising of isolates from outbreak, sporadic and carrier cases. The genomes showed high genetic relatedness with limited opportunity for gene acquisition as evident from pan-genome structure. Given that pseudogenisation is an active process in S. Typhi, we further investigated core and pan-genome profiles of functional and pseudogenes separately. We observed a decline in core functional gene content and a significant increase in accessory pseudogene content. Upon functional classification, genes encoding metabolic functions formed a major constituent of pseudogenes as well as core functional gene clusters with SNPs. Further, an in-depth analysis of accessory pseudogene content revealed the existence of heterogeneous complements of functional and pseudogenes among the strains. In addition, these polymorphic genes were also enriched in metabolism related functions. Thus, the study highlights the existence of heterogeneous strains in a population with varying metabolic potential and that S. Typhi possibly resorts to metabolic fine tuning for its adaptation. Scientific Reports 4 doi: 10.1038/srep07457
    Digitale ISSN: 2045-2322
    Thema: Allgemeine Naturwissenschaft
    Publiziert von Springer Nature
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    Issue Information (2014)
    Wiley
    Details
    Publikationsdatum: 2014-12-13
    Beschreibung: No abstract is available for this article.
    Print ISSN: 0048-6604
    Digitale ISSN: 1944-799X
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley im Namen von American Geophysical Union (AGU).
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    Highly Sensitive Ultraviolet Photodetectors Fabricated from ZnO Quantum Dots/Carbon Nanodots Hybrid Films (2014)
    Springer Nature
    Details
    Publikationsdatum: 2014-12-13
    Beschreibung: Ultraviolet photodetectors have been fabricated from ZnO quantum dots/carbon nanodots hybrid films, and the introduction of carbon nanodots improves the performance of the photodetectors greatly. The photodetectors can be used to detect very weak ultraviolet signals (as low as 12 nW/cm2). The detectivity and noise equivalent power of the photodetector can reach 3.1 × 1017 cmHz1/2/W and 7.8 × 10−20 W, respectively, both of which are the best values ever reported for ZnO-based photodetectors. The mechanism for the high sensitivity of the photodetectors has been attributed to the enhanced carrier-separation at the ZnO/C interface. Scientific Reports 4 doi: 10.1038/srep07469
    Digitale ISSN: 2045-2322
    Thema: Allgemeine Naturwissenschaft
    Publiziert von Springer Nature
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    n-3 PUFA supplementation benefits microglial responses to myelin pathology (2014)
    Springer Nature
    Details
    Publikationsdatum: 2014-12-13
    Beschreibung: Microglia represent rational but challenging targets for improving white matter integrity because of their dualistic protective and toxic roles. The present study examines the effect of Omega-3 polyunsaturated fatty acids (n-3 PUFAs) on microglial responses to myelin pathology in primary cultures and in the cuprizone mouse model of multiple sclerosis (MS), a devastating demyelination disease. Docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), the two main forms of n-3 PUFAs in the brain, inhibited the release of nitric oxide and tumor necrosis factor-α from primary microglia upon IFN-γ and myelin stimulation. DHA and EPA also enhanced myelin phagocytosis in vitro. Therefore, n-3 PUFAs can inhibit inflammation while at the same time enhancing beneficial immune responses such as microglial phagocytosis. In vivo studies demonstrated that n-3 PUFA supplementation reduced cuprizone-induced demyelination and improved motor and cognitive function. The positive effects of n-3 PUFAs were accompanied by a shift in microglial polarization toward the beneficial M2 phenotype both in vitro and in vivo. These results suggest that n-3 PUFAs may be clinically useful as immunomodulatory agents for demyelinating diseases through a novel mechanism involving microglial phenotype switching. Scientific Reports 4 doi: 10.1038/srep07458
    Digitale ISSN: 2045-2322
    Thema: Allgemeine Naturwissenschaft
    Publiziert von Springer Nature
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    Free-standing Fe2O3 nanomembranes enabling ultra-long cycling life and high rate capability for Li-ion batteries (2014)
    Springer Nature
    Details
    Publikationsdatum: 2014-12-13
    Beschreibung: With Fe2O3 as a proof-of-concept, free-standing nanomembrane structure is demonstrated to be highly advantageous to improve the performance of Li-ion batteries. The Fe2O3 nanomembrane electrodes exhibit ultra-long cycling life at high current rates with satisfactory capacity (808 mAh g−1 after 1000 cycles at 2 C and 530 mAh g−1 after 3000 cycles at 6 C) as well as repeatable high rate capability up to 50 C. The excellent performance benefits particularly from the unique structural advantages of the nanomembranes. The mechanical feature can buffer the strain of lithiation/delithiation to postpone the pulverization. The two-dimensional transport pathways in between the nanomembranes can promote the pseudo-capacitive type storage. The parallel-laid nanomembranes, which are coated by polymeric gel-like film and SEI layer with the electrolyte in between layers, electrochemically behave like numerous “mini-capacitors” to provide the pseudo-capacitance thus maintain the capacity at high rate. Scientific Reports 4 doi: 10.1038/srep07452
    Digitale ISSN: 2045-2322
    Thema: Allgemeine Naturwissenschaft
    Publiziert von Springer Nature
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    How water molecules affect the catalytic activity of hydrolases - A XANES study of the local structures of peptide deformylase (2014)
    Springer Nature
    Details
    Publikationsdatum: 2014-12-13
    Beschreibung: Peptide deformylase (PDF) is a prokaryotic enzyme that catalyzes the deformylation of nascent peptides generated during protein synthesis and water molecules play a key role in these hydrolases. Using X-ray absorption near edge spectroscopy (XANES) and ab initio calculations we accurately probe the local atomic environment of the metal ion binding in the active site of PDF at different pH values and with different metal ions. This new approach is an effective way to monitor existing correlations among functions and structural changes. We show for the first time that the enzymatic activity depends on pH values and metal ions via the bond length of the nearest coordinating water (Wat1) to the metal ion. Combining experimental and theoretical data we may claim that PDF exhibits an enhanced enzymatic activity only when the distance of the Wat1 molecule with the metal ion falls in the limited range from 2.15 to 2.55 Å. Scientific Reports 4 doi: 10.1038/srep07453
    Digitale ISSN: 2045-2322
    Thema: Allgemeine Naturwissenschaft
    Publiziert von Springer Nature
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    MORC1 represses transposable elements in the mouse male germline (2014)
    Springer Nature
    Details
    Publikationsdatum: 2014-12-14
    Beschreibung: Article The Microrchidia (Morc) family of GHKL ATPases are important repressors of transposons and other DNA-methylated and silent genes in A. thaliana . Here, the authors show that MORC1 is responsible for repression and methylation of specific classes of transposons in the mouse male germline. Nature Communications doi: 10.1038/ncomms6795 Authors: William A. Pastor, Hume Stroud, Kevin Nee, Wanlu Liu, Dubravka Pezic, Sergei Manakov, Serena A. Lee, Guillaume Moissiard, Natasha Zamudio, Déborah Bourc’his, Alexei A. Aravin, Amander T. Clark, Steven E. Jacobsen
    Digitale ISSN: 2041-1723
    Thema: Biologie , Chemie und Pharmazie , Allgemeine Naturwissenschaft , Physik
    Publiziert von Springer Nature
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    An efficient radiative cooling approximation for use in hydrodynamic simulations (2014)
    Oxford University Press
    Details
    Publikationsdatum: 2014-12-14
    Beschreibung: To make relevant predictions about observable emission, hydrodynamical simulation codes must employ schemes that account for radiative losses, but the large dimensionality of accurate radiative transfer schemes is often prohibitive. Stamatellos and collaborators introduced a scheme for smoothed particle hydrodynamics (SPH) simulations based on the notion of polytropic pseudo-clouds that uses only local quantities to estimate cooling rates. The computational approach is extremely efficient and works well in cases close to spherical symmetry, such as in star formation problems. Unfortunately, the method, which takes the local gravitational potential as an input, can be inaccurate when applied to non-spherical configurations, limiting its usefulness when studying discs or stellar collisions, among other situations of interest. Here, we introduce the ‘pressure scale height method,’ which incorporates the fluid pressure scaleheight into the determination of column densities and cooling rates, and show that it produces more accurate results across a wide range of physical scenarios while retaining the computational efficiency of the original method. The tested models include spherical polytropes as well as discs with specified density and temperature profiles. We focus on applying our techniques within an SPH code, although our method can be implemented within any particle-based Lagrangian or grid-based Eulerian hydrodynamic scheme. Our new method may be applied in a broad range of situations, including within the realm of stellar interactions, collisions, and mergers.
    Print ISSN: 0035-8711
    Digitale ISSN: 1365-2966
    Thema: Physik
    Publiziert von Oxford University Press
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    Clusterin facilitates stress-induced lipidation of LC3 and autophagosome biogenesis to enhance cancer cell survival (2014)
    Springer Nature
    Details
    Publikationsdatum: 2014-12-14
    Beschreibung: Article The induction of autophagy under stress conditions such as chemotherapy is a contributing factor towards resistance to anticancer therapy. Here, Zhang et al . identify the molecular chaperone clusterin as an adaptor that facilitates lipidation of LC3 and autophagosome biogenesis. Nature Communications doi: 10.1038/ncomms6775 Authors: Fan Zhang, Masafumi Kumano, Eliana Beraldi, Ladan Fazli, Caigan Du, Susan Moore, Poul Sorensen, Amina Zoubeidi, Martin E. Gleave
    Digitale ISSN: 2041-1723
    Thema: Biologie , Chemie und Pharmazie , Allgemeine Naturwissenschaft , Physik
    Publiziert von Springer Nature
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    Extremely Low Frequency Band Station for Natural Electromagnetic Noise Measurement (2014)
    Wiley
    Details
    Publikationsdatum: 2014-12-14
    Beschreibung: A new permanent ELF measurement station has been deployed in Sierra Nevada, Spain. It is composed of two magnetometers, oriented NS and EW, respectively. At 10 Hz, their sensitivity is 19 μ zV/pT and the Signal to Noise Ratio (SNR) is 28 dB for a time-varying signal of 1 pT, the expected field amplitude in Sierra Nevada. The station operates for frequencies below 24 Hz. The magnetometers, together with their corresponding electronics, have been specifically designed to achieve such an SNR for small signals. They are based on high-resolution search coils with ferromagnetic core and 10 6 turns, operating in limited geometry configuration. Different system noise sources are considered and a study of the SNR is also included. Finally, some initial Schumann resonance measurements are presented in order to validate the performance of the measurement station, including one hour length spectra, daily variations of resonance amplitudes and frequencies for the different seasons, and a three day spectrogram.
    Print ISSN: 0048-6604
    Digitale ISSN: 1944-799X
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley im Namen von American Geophysical Union (AGU).
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    Steered migration in hard rock environments (2014)
    Wiley
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    Publikationsdatum: 2014-12-16
    Beschreibung: ABSTRACT Hard rock seismic exploration normally has to deal with rather complex geological environments. These types of environments are usually characterized by a large number of local heterogeneity (e.g., faults, fracture zones, and steeply dipping interfaces). The seismic data from such environments often have a poor signal-to-noise ratio because of the complexity of hard rock geology. To be able to obtain reliable images of subsurface structures in such geological conditions, processing algorithms that are capable of handling seismic data with a low signal-to-noise ratio are required for a reflection seismic exploration. In this paper, we describe a modification of the 3D Kirchhoff post-stack migration algorithm that utilizes coherency attributes obtained by the diffraction imaging algorithm in 3D to steer the main Kirchhoff summation. The application to a 3D synthetic model shows the stability of the presented steered migration to the presence of high level of the random noise. A test on the 3D seismic volume, acquired on a mine site located in Western Australia, reveals the capability of the approach to image steep and sharp objects such as fracture and fault zones and lateral heterogeneity.
    Print ISSN: 0016-8025
    Digitale ISSN: 1365-2478
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley
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    Issue Information (2014)
    Wiley
    Details
    Publikationsdatum: 2014-12-16
    Beschreibung: No abstract is available for this article.
    Print ISSN: 0148-0227
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley im Namen von American Geophysical Union (AGU).
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    Simulating Diurnal Variations Over the Southeastern United States (2014)
    Wiley
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    Publikationsdatum: 2014-12-16
    Beschreibung: The diurnal variations from a high-resolution regional climate model (Regional Spectral Model; RSM) are analyzed from 6 independent decade long integrations using lateral boundary forcing data separately from the National Centers for Environmental Prediction Reanalysis 2 (NCEPR2), and European Center for Medium-Range Weather Forecasts (ECMWF) 40-year Reanalysis (ERA40) and the 20 th Century Reanalysis (20CR). With each of these lateral boundary forcing data, the RSM is integrated separately using two convection schemes: the Relaxed Arakawa-Schubert (RAS) and Kain-Fritsch (KF) schemes. The results show that RSM integrations forced with 20CR have the least fidelity in depicting the seasonal cycle and diurnal variability of precipitation and surface temperature over the Southeastern United States (SEUS). The remaining four model simulations show comparable skills. The differences in the diurnal amplitude of rainfall during the summer months of the 20CR forced integration from the corresponding NCEPR2 forced integration, for example, is found to be largely from the transient component of the moisture flux convergence. The root mean square error (RMSE) of the seasonal cycle of precipitation and surface temperature of the other four simulations (not forced by 20CR) were comparable to each other and highest in the summer months. But the RMSE of the diurnal amplitude of precipitation and the timing of its diurnal zenith were largest during winter months and least during summer and fall months in the four model simulations (not forced by 20CR). The diurnal amplitude of surface temperature in comparison showed far less fidelity in all models. The phase of the diurnal maximum of surface temperature however showed significantly better validation with corresponding observations in all of the 6 model simulations
    Print ISSN: 0148-0227
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley im Namen von American Geophysical Union (AGU).
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    Tracking major storms from microseismic and hydroacoustic observations on the seafloor (2014)
    Wiley
    Details
    Publikationsdatum: 2014-12-15
    Beschreibung: Ocean wave activity excites seismic waves that propagate through the solid earth, known as microseismic noise. Here we use a network of 57 ocean-bottom seismometers (OBS) deployed around La Réunion Island in the southwest Indian Ocean to investigate the noise generated in the secondary microseismic band as a tropical cyclone moved over the network. Spectral and polarization analyses show that microseisms strongly increase in the 0.1 - 0.35 Hz frequency band as the cyclone approaches, and that this noise is composed of both compressional and surface waves, confirming theoretical predictions. We infer the location of maximum noise amplitude in space and time, and show that it coincides roughly with the location of maximum ocean-wave interactions. Although this analysis was performed retrospectively, microseisms recorded on the seafloor can be considered a novel source of information for future real-time tracking and monitoring of major storms, complementing atmospheric, oceanographic and satellite observations.
    Print ISSN: 0094-8276
    Digitale ISSN: 1944-8007
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley im Namen von American Geophysical Union (AGU).
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    Galápagos Coral Reef Persistence after ENSO Warming Across an Acidification Gradient (2014)
    Wiley
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    Publikationsdatum: 2014-12-15
    Beschreibung: Anthropogenic CO 2 is causing warming and ocean acidification. Coral reefs are being severely impacted, yet confusion lingers regarding how reefs will respond to these stressors over this century. Since the 1982-83 El Niño-Southern Oscillation warming event, the persistence of reefs around the Galápagos Islands has differed across an acidification gradient. Reefs disappeared where pH 〈 8.0 and aragonite saturation state (Ω arag ) ≤ 3 and have not recovered, whereas one reef has persisted where pH 〉 8.0 and Ω arag  〉 3. Where upwelling is greatest, calcification by massive Porites is higher than predicted by a published relationship with temperature despite high CO 2 , possibly due to elevated nutrients. However, skeletal P/Ca, a proxy for phosphate exposure, negatively correlates with density ( R  = -0.822, p  〈 0.0001). We propose that elevated nutrients have the potential to exacerbate acidification by depressing coral skeletal densities and further increasing bioerosion already accelerated by low pH.
    Print ISSN: 0094-8276
    Digitale ISSN: 1944-8007
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley im Namen von American Geophysical Union (AGU).
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    Changes to the temporal distribution of daily precipitation (2014)
    Wiley
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    Publikationsdatum: 2014-12-15
    Beschreibung: Changes to the temporal distribution of daily precipitation were investigated using a dataset of 12,513 land-based stations from the Global Historical Climatology Network (GHCN). The distribution of precipitation was measured using the Gini index (which describes how uniformly precipitation is distributed throughout a year) and the annual number of wet days. The Mann-Kendall test and a regression analysis were used to assess the direction and rate of change to both indices. Over the period of 1976-2000, East Asia, central America and Brazil exhibited a decrease in the number of both wet and light precipitation days, and eastern Europe exhibited a decrease in the number of both wet and moderate precipitation days. In contrast, the USA, southern South America, western Europe and Australia exhibited an increase in the number of both wet and light precipitation days. Trends in both directions were field significant at the global scale.
    Print ISSN: 0094-8276
    Digitale ISSN: 1944-8007
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley im Namen von American Geophysical Union (AGU).
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    Effects of the post-perovskite phase change on the observed geoid (2014)
    Wiley
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    Publikationsdatum: 2014-12-15
    Beschreibung: In the lowermost mantle, seismic velocity variations beneath Pacific margins have been related to the perovskite (pv) to post-perovskite (pPv) phase transition. We investigate the influence of this phase transformation on the geoid using 3D spherical mantle circulation models based on a seismic tomography model and strong lateral viscosity variations in the lower mantle. We demonstrate that the geoid anomalies are strongly affected by the presence of pPv because of phase-dependent viscosity changes relative to the surrounding mantle. Whereas geoid heights above subduction zones are increased for high-viscosity pPv, the presence of weak pPv reduces them, thereby improving the fit to the observed geoid. An investigation using two different tomography models, different pPv density contrasts, and the presence or absence of a global thermal boundary layer and of lateral viscosity variations in the lower mantle demonstrate the various effects of weak pPv on the geoid.
    Print ISSN: 0094-8276
    Digitale ISSN: 1944-8007
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley im Namen von American Geophysical Union (AGU).
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    Interdecadal Pacific variability and eastern Australian mega-droughts over the last millennium (2014)
    Wiley
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    Publikationsdatum: 2014-12-15
    Beschreibung: The Interdecadal Pacific Oscillation (IPO) influences multidecadal drought risk across the Pacific, but there are no millennial-length, high resolution IPO reconstructions for quantifying long-term drought risk. In Australia, drought risk increases in positive phases of the IPO, yet few suitable rainfall proxies and short (~100 y) instrumental records mean large uncertainties remain around drought frequency and duration. Likewise, it is unknown whether mega-droughts have occurred in Australia's past. In this study, an atmospheric teleconnection in the Indian Ocean mid-latitudes linking East Antarctica and Australia is exploited to produce the first accurate, annually dated millennial-length IPO reconstruction from the Law Dome (East Antarctica) ice core. Combined with an eastern Australian rainfall proxy from Law Dome, the first millennial-length Australian mega-drought (〉5 y duration) reconstruction is presented. Eight mega-droughts are identified including one 39 y drought (AD 1174–1212), which occurred during an unprecedented century of aridity (AD 1102–1212).
    Print ISSN: 0094-8276
    Digitale ISSN: 1944-8007
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley im Namen von American Geophysical Union (AGU).
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    Symmetry, Vol. 6, Pages 1026-1036: Benjamin–Bona–Mahony Equation with Variable Coefficients: Conservation Laws (2014)
    MDPI Publishing
    In: Symmetry
    Details
    Publikationsdatum: 2014-12-16
    Beschreibung: This paper aims to construct conservation laws for a Benjamin–Bona–Mahony equation with variable coefficients, which is a third-order partial differential equation. This equation does not have a Lagrangian and so we transform it to a fourth-order partial differential equation, which has a Lagrangian. The Noether approach is then employed to construct the conservation laws. It so happens that the derived conserved quantities fail to satisfy the divergence criterion and so one needs to make adjustments to the derived conserved quantities in order to satisfy the divergence condition. The conservation laws are then expressed in the original variable. Finally, a conservation law is used to obtain exact solution of a special case of the Benjamin–Bona–Mahony equation.
    Digitale ISSN: 2073-8994
    Thema: Mathematik , Physik
    Publiziert von MDPI Publishing
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    The onset, retreat and the length of growing season in the north-eastern region of Sri Lanka (2014)
    Wiley
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    Publikationsdatum: 2014-12-17
    Beschreibung: ABSTRACT The onset, retreat and the length of growing season in the north-eastern region of Sri Lanka were investigated using daily rainfall data for the period 1961 to 2000. Data from three weather stations situated in the coastal belt in the northern and eastern parts of Sri Lanka (Jaffna, Trincomalee and Batticaloa) that receive rainfall predominantly from the northeast monsoon were selected for this study. A method based on cumulative rainy days was utilized in the determination of the onset and retreat dates. It is shown that there is substantial interannual variability in onset and retreat dates. The mean onset and retreat dates fall on the standard week 38.3 ± 2.7 and 53.0 ± 2.9, respectively. The mean duration of the growing season is 14.7 ± 3.4 weeks. The retreat date and thus the length of growing season could be extended by 2 weeks if the probability of occurrence of rain during the onset is favourable for the retreat. The results indicate that there has been no significant trend in the onset and retreat dates during the last 40 years in the dry zone of Sri Lanka. The onset date and the length of growing season are weakly correlated with early onset dates leading to longer growing seasons. The study concludes that rainy days could be used successfully to determine the mean rainfall onset and retreat dates in the dry zone of Sri Lanka.
    Print ISSN: 0899-8418
    Digitale ISSN: 1097-0088
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley
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    Revision and extension of the composite Carlisle rainfall record, northwest England: 1757–2012 (2014)
    Wiley
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    Publikationsdatum: 2014-12-17
    Beschreibung: ABSTRACT A 256-year composite monthly rainfall record representative of the lowlands around Carlisle, northwest England is presented, providing the third longest instrumental record of rainfall available in the UK and expanding the sparse network of long homogenous rainfall series. This article describes the construction of the rainfall record for the period 1757–2012 and presents analyses of long-term annual and seasonal variability, with a particular focus on wet/dry extremes. Three primary rainfall records from Carlisle underpin the reconstruction, with others selected based on length of record and proximity to the primary recording stations. Linear regression and adjustment factors were applied to create a homogenous continuous rainfall record, assessed by cross-comparison with other long-term UK rainfall records. Double-mass curve and standard normal homogeneity tests using long records representative of Manchester and Appleby confirmed that the Carlisle record is homogenous, but includes a period of uncertainty during the period 1886–1911, which is within the recognized instrumental phase of recording. Analysis of the series shows long-term temporal rainfall variability, with seasonal rainfall totals showing a significant increase in winter rainfall. An increasing trend in annual rainfall was also identified but is not significant. Several previously documented notable extreme wet (e.g. winter 1834) and dry (e.g. summer 1995) seasons were identified, along with several additional seasons (e.g. winter 1764 and summer 1891) that can be considered as extreme and occurred during the more poorly understood 18th and early 19th centuries. These results allow recent extremes to be placed within the context of long-term natural variability. At the decadal timescale seasonal rainfall totals are highly variable. The wettest season fluctuates between autumn and summer until the late 20th century (1990s), when winter became wetter than any other season for the first time on record.
    Print ISSN: 0899-8418
    Digitale ISSN: 1097-0088
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley
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    A conceptual model for assessing rainfall and vegetation trends in sub-Saharan Africa from satellite data (2014)
    Wiley
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    Publikationsdatum: 2014-12-17
    Beschreibung: ABSTRACT Policymakers, governments and aid agencies require operational environmental monitoring in support of evidence-based policy-making and resource deployment in crisis situations. For Africa, this is only feasible at sub-continental scale with a large network of automated meteorological stations, a large number of highly coordinated field observers or with satellite remote sensing. The challenge with satellite data lies in the derivation of meaningful environmental indicators. This article describes a conceptual framework for understanding satellite-derived indicators of rainfall and vegetation greenness trends over Africa. It attributes observed vegetation changes to climatic (i.e. rainfall linked) and non-climatic drivers. A decade of annual rainfall and vegetation data over sub-Saharan Africa was analysed using satellite-based rainfall estimates [Famine Early Warning System Rainfall Estimation 2.0 (FEWSNET RFE 2.0)] from National Oceanic and Atmospheric Administration's (NOAA's) Climate Prediction Centre and the Normalized Difference Vegetation Index (NDVI) obtained from the Satellite Pour l'Observation de la Terre Vegetation (SPOT-VGT) sensor. Rainfall and vegetation greenness trends were analysed for 759 administrative regions of sub-Saharan Africa to identify those regions that have experienced a negative, positive or stable rainfall/vegetation trend over the period 2001–2010. The character of the relationship between the annual rainfall and max NDVI trends were examined to identify areas where the changes in greenness could be attributed to climatic (rainfall) and non-climatic (human land use or ecological disturbance) changes. Regions where increasing rainfall was associated with vegetation greening were found in West Africa, Central African Republic, West Cameroon and northeastern part of South Africa, whereas areas with evidence of ‘climatic vegetation degradation’ were located in Southern Madagascar, Nigeria, Kenya and the Garden Route region of South Africa.
    Print ISSN: 0899-8418
    Digitale ISSN: 1097-0088
    Thema: Geologie und Paläontologie , Physik
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  • 49
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    Field Observations of Wave-Driven Circulation over Spur and Groove Formations on a Coral Reef (2014)
    Wiley
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    Publikationsdatum: 2014-12-17
    Beschreibung: Spur and groove (SAG) formations are found on the forereefs of many coral reefs worldwide. Modeling results have shown that SAG formations together with shoaling waves induce a nearshore Lagrangian circulation pattern of counter-rotating circulation cells, but these have never been observed in the field. We present results from two separate field studies of SAG formations on Palmyra Atoll which show their effect on waves to be small, but reveal a persistent order 1 cm/s depth-averaged Lagrangian offshore flow over the spur and onshore flow over the grooves. This circulation was stronger for larger, directly-incident waves and low alongshore flow conditions, consistent with predictions from modeling. Favorable forcing conditions must be maintained on the order of one hour to accelerate and develop the SAG circulation cells. The primary cross- and alongshore depth-averaged momentum balances were between the pressure gradient, radiation stress gradient and nonlinear convective terms, and the bottom drag was similar to values found on other reefs. The vertical structure of these circulation cells was previously unknown and the results show a complex horizontal offshore Lagrangian flow over the spurs near the surface driven by alongshore variability in radiation stress gradients. Vertical flow was downward over the spur and upward over the groove, likely driven by alongshore differences in bottom stress and not by vortex forcing. This article is protected by copyright. All rights reserved.
    Print ISSN: 0148-0227
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley im Namen von American Geophysical Union (AGU).
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  • 50
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    Energy and heat fluxes due to vertically-propagating Yanai waves observed in the equatorial Indian ocean (2014)
    Wiley
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    Publikationsdatum: 2014-12-17
    Beschreibung: Shipboard current measurements in the equatorial Indian Ocean in October and November of 2011 revealed oscillations in the meridional velocity with amplitude ~ 0.10m/s. These were clearest in a layer extending from ~300 to 600 m depth and had periods near 3 weeks. Phase propagation was upward. Measurements from two sequential time series at the equator, four meridional transects and one zonal transect are used to identify the oscillation as a Yanai wave packet and to establish its dominant frequency and vertical wavelength. The Doppler shift is accounted for, so that measured wave properties are translated into the reference frame of the mean zonal flow. We take advantage of the fact that, in the depth range where the wave signal was clearest, the time-averaged current and buoyancy frequency were nearly uniform with depth, allowing application of the classical theoretical representation of vertically propagating plane waves. Using the theory, we estimate wave properties that are not directly measured, such as the group velocity and the zonal wavelength and phase speed. The theory predicts a vertical energy flux that is comparable to that carried by midlatitude near-inertial waves. We also quantify the wave-driven meridional heat flux and the Stokes drift. This article is protected by copyright. All rights reserved.
    Print ISSN: 0148-0227
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley im Namen von American Geophysical Union (AGU).
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    Issue Information (2014)
    Wiley
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    Publikationsdatum: 2014-12-17
    Beschreibung: No abstract is available for this article.
    Print ISSN: 0148-0227
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley im Namen von American Geophysical Union (AGU).
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    Impact of measurement uncertainties on determination of chlorophyll-specific absorption coefficient for marine phytoplankton (2014)
    Wiley
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    Publikationsdatum: 2014-12-17
    Beschreibung: Understanding variability in the chlorophyll-specific absorption of marine phytoplankton, a ph * Chl (λ) , is essential for primary production modelling, calculation of underwater light field characteristics, and development of algorithms for remote sensing of chlorophyll concentrations. Previous field and laboratory studies have demonstrated significant apparent variability in a ph * Chl (λ) for natural samples and algal cultures. However, the potential impact of measurement uncertainties on derived values of a ph * Chl (λ) has received insufficient study. This study presents an analysis of measurement uncertainties for a data set collected in the Ligurian Sea in Spring and assesses the impact on estimates of a ph * Chl (λ) . It is found that a large proportion of apparent variability in this set of a ph * Chl (λ) can be attributed to measurement errors. Application of the same analysis to the global NOMAD data set suggests that a significant fraction of variability in a ph * Chl (λ) may also be due to measurement errors. This article is protected by copyright. All rights reserved.
    Print ISSN: 0148-0227
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley im Namen von American Geophysical Union (AGU).
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  • 53
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    An optimal XBT-based monitoring system for the South Atlantic Meridional Overturning Circulation at 34°S (2014)
    Wiley
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    Publikationsdatum: 2014-12-17
    Beschreibung: The South Atlantic is an important pathway for the inter-basin exchanges of heat and freshwater with strong influence on the global meridional overturning stability and variability. Along the 34°S parallel, a quarterly, high resolution XBT transect (AX18) samples the temperature structure in the upper ocean. The AX18 transect has been shown to be a useful component of a meridional overturning monitoring system of the region. However, a feasible, cost-effective design for an XBT-based system has not yet been developed. Here we use a high-resolution ocean assimilation product to simulate an XBT-based observational system across the South Atlantic. The sensitivity of the meridional heat transport, meridional overturning circulation, and geostrophic velocities to key observational and methodological assumptions is studied. Key assumptions taken into account are horizontal and temporal sampling of the transect, salinity and deep temperature inference, as well as the level of reference for geostrophic velocities. With the current sampling strategy, the largest errors in the meridional overturning and heat transport estimations are the reference (barotropic) velocity and the western boundary resolution. We show how altimetry can be used along with hydrography to resolve the barotropic component of the flow. We use the results obtained by the state estimation under observational assumptions to make recommendations for potential improvements in the AX18 transect implementation. This article is protected by copyright. All rights reserved.
    Print ISSN: 0148-0227
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley im Namen von American Geophysical Union (AGU).
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    Galactic outflow and diffuse gas properties at z 〉= 1 using different baryonic feedback models (2014)
    Oxford University Press
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    Publikationsdatum: 2014-12-17
    Beschreibung: We measure and quantify properties of galactic outflows and diffuse gas at z ≥ 1 in cosmological hydrodynamical simulations. Our novel subresolution model, Multi-Phase Particle Integrator (MUPPI), implements supernova feedback using fully local gas properties, where the wind velocity and mass loading are not given as input. We find the following trends at z  = 2 by analysing central galaxies having a stellar mass higher than 10 9 M . The outflow velocity and mass outflow rate ( $\dot{M}_{\rm out}$ ) exhibit positive correlations with galaxy mass and with the star formation rate (SFR). However, most of the relations present a large scatter. The outflow mass loading factor () is between 0.2 and 10. The comparison effective model generates a constant outflow velocity, and a negative correlation of with halo mass. The number fraction of galaxies where outflow is detected decreases at lower redshifts, but remains more than 80 per cent over z  = 1–5. The outflow velocity correlation with SFR becomes flatter at z  = 1, and displays a negative correlation with halo mass in massive galaxies. Our study demonstrates that both the MUPPI and effective models produce significant outflows at ~1/10 of the virial radius; at the same time shows that the properties of outflows generated can be different from the input speed and mass loading in the effective model. Our MUPPI model, using local properties of gas in the subresolution recipe, is able to develop galactic outflows whose properties correlate with global galaxy properties , and consistent with observations.
    Print ISSN: 0035-8711
    Digitale ISSN: 1365-2966
    Thema: Physik
    Publiziert von Oxford University Press
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  • 55
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    Phosphorylation of LRRK2 by casein kinase 1α regulates trans-Golgi clustering via differential interaction with ARHGEF7 (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-17
    Beschreibung: Article The kinase LRRK2 is implicated in Parkinson’s disease progression and is known to be phosphorylated. Chia et al. show that this phosphorylation is mediated by the kinase CK1a, and is required for the recruitment of LRRK2 to Golgi-derived vesicles, suggesting a role for this protein in Golgi maintenance. Nature Communications doi: 10.1038/ncomms6827 Authors: Ruth Chia, Sara Haddock, Alexandra Beilina, Iakov N. Rudenko, Adamantios Mamais, Alice Kaganovich, Yan Li, Ravindran Kumaran, Michael A. Nalls, Mark R. Cookson
    Digitale ISSN: 2041-1723
    Thema: Biologie , Chemie und Pharmazie , Allgemeine Naturwissenschaft , Physik
    Publiziert von Springer Nature
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    Control of membrane gaps by synaptotagmin-Ca2+ measured with a novel membrane distance ruler (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-17
    Beschreibung: Article Synaptotagmin-1 (syt-1) triggers fast synchronous neurotransmission mediated by fusion of synaptic vesicles with presynaptic membranes. Here Lin et al. use inter-membrane FRET combined with DNA rulers as calibration standards to quantify Ca 2+ -induced changes in membrane distances mediated by syt-1. Nature Communications doi: 10.1038/ncomms6859 Authors: Chao-Chen Lin, Jan Seikowski, Angel Pérez-Lara, Reinhard Jahn, Claudia Höbartner, Peter Jomo Walla
    Digitale ISSN: 2041-1723
    Thema: Biologie , Chemie und Pharmazie , Allgemeine Naturwissenschaft , Physik
    Publiziert von Springer Nature
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    Direct evidence for BBSome-associated intraflagellar transport reveals distinct properties of native mammalian cilia (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-17
    Beschreibung: Article Loss of olfactory function is one of the many symptoms of the ciliopathy Bardet–Biedl syndrome. Williams et al . show that Bardet–Biedl proteins are components of intraflagellar transport particles within cilia, and directly visualize their trafficking in native mammalian olfactory neurons. Nature Communications doi: 10.1038/ncomms6813 Authors: Corey L. Williams, Jeremy C. McIntyre, Stephen R. Norris, Paul M. Jenkins, Lian Zhang, Qinglin Pei, Kristen Verhey, Jeffrey R. Martens
    Digitale ISSN: 2041-1723
    Thema: Biologie , Chemie und Pharmazie , Allgemeine Naturwissenschaft , Physik
    Publiziert von Springer Nature
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    A chromatin activity-based chemoproteomic approach reveals a transcriptional repressome for gene-specific silencing (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-17
    Beschreibung: Article Immune cell pro-inflammatory gene expression is suppressed following prolonged stimulation. Using a chemoproteomic approach, the authors show that methyltransferase G9a forms a protein complex that promotes the transcriptional repressor activity of c-Myc to repress inflammation-induced gene expression. Nature Communications doi: 10.1038/ncomms6733 Authors: Cui Liu, Yanbao Yu, Feng Liu, Xin Wei, John A. Wrobel, Harsha P. Gunawardena, Li Zhou, Jian Jin, Xian Chen
    Digitale ISSN: 2041-1723
    Thema: Biologie , Chemie und Pharmazie , Allgemeine Naturwissenschaft , Physik
    Publiziert von Springer Nature
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  • 59
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    Low MITF/AXL ratio predicts early resistance to multiple targeted drugs in melanoma (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-17
    Beschreibung: Article Increased expression of MITF transcription factor is thought to promote melanoma progression and kinase inhibitor resistance. Here Muller et al . show that MITF loss is also common in melanomas and confers kinase inhibitor resistance due to upregulation of AXL and other receptor tyrosine kinases. Nature Communications doi: 10.1038/ncomms6712 Authors: Judith Müller, Oscar Krijgsman, Jennifer Tsoi, Lidia Robert, Willy Hugo, Chunying Song, Xiangju Kong, Patricia A. Possik, Paulien D. M. Cornelissen-Steijger, Marnix H Geukes Foppen, Kristel Kemper, Colin R. Goding, Ultan McDermott, Christian Blank, John Haanen, Thomas G. Graeber, Antoni Ribas, Roger S. Lo, Daniel S. Peeper
    Digitale ISSN: 2041-1723
    Thema: Biologie , Chemie und Pharmazie , Allgemeine Naturwissenschaft , Physik
    Publiziert von Springer Nature
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    Atmospheric Response in Summer linked to Recent Arctic Sea Ice Loss (2014)
    Wiley
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    Publikationsdatum: 2014-12-17
    Beschreibung: Since 2007 a large decline in Arctic sea ice has been observed. The large-scale atmospheric circulation response to this decline is investigated in ERA-Interim reanalyses and HadGEM3 climate model experiments. In winter, post-2007 observed circulation anomalies over the Arctic, North Atlantic and Eurasia are small compared to interannual variability. In summer, the post-2007 observed circulation is dominated by an anticyclonic anomaly over Greenland which has a large signal-to-noise ratio. Climate model experiments driven by observed SST and sea ice anomalies are able to capture the summertime pattern of observed circulation anomalies, although the magnitude is a third of that observed. The experiments suggest warm SSTs and reduced sea ice in the Labrador Sea lead to warm temperature anomalies in lower troposphere which weaken the westerlies over North America through thermal wind balance. The experiments also capture cyclonic anomalies over north-western Europe, which are consistent with downstream Rossby wave propagation.
    Print ISSN: 0035-9009
    Digitale ISSN: 1477-870X
    Thema: Geographie , Physik
    Publiziert von Wiley
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    Massively Sub-wavelength Guiding of Electromagnetic Waves (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-17
    Beschreibung: Recently a new form of ultra-thin flexible waveguide consisting of a conducting comb-like structure with a thickness of the order of 1/600th of the operating wavelength was presented. However, whilst the thickness of the guide was massively sub-wavelength, the remaining dimensions (the height and period of the comb) were much longer. In this paper we propose, and experimentally verify, that a modified guiding geometry consisting of a chain of ultra-thin conducting spirals allows guiding of electromagnetic waves with wavelengths that are many times (40+) longer than any characteristic dimension of the guide, enabling super-sub-wavelength guiding and localisation of electromagnetic energy. Scientific Reports 4 doi: 10.1038/srep07495
    Digitale ISSN: 2045-2322
    Thema: Allgemeine Naturwissenschaft
    Publiziert von Springer Nature
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    Levodopa/benserazide microsphere (LBM) prevents L-dopa induced dyskinesia by inactivation of the DR1/PKA/P-tau pathway in 6-OHDA-lesioned Parkinson's rats (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-17
    Beschreibung: L-3, 4-dihydroxyphenylalanine (L-dopa) is the gold standard for symptomatic treatment of Parkinson's disease (PD), but long-term therapy is associated with the emergence of L-dopa-induced dyskinesia (LID). In the present study, L-dopa and benserazide were loaded by poly (lactic-co-glycolic acid) microspheres (LBM), which can release levodopa and benserazide in a sustained manner in order to continuous stimulate dopaminergic receptors. We investigated the role of striatal DR1/PKA/P-tau signal transduction in the molecular event underlying LID in the 6-OHDA-lesioned rat model of PD. We found that animals rendered dyskinetic by L-dopa treatment, administration of LBM prevented the severity of AIM score, as well as improvement in motor function. Moreover, we also showed L-dopa elicits profound alterations in the activity of three LID molecular markers, namely DR1/PKA/P-tau (ser396). These modifications are totally prevented by LBM treatment, a similar way to achieve continuous dopaminergic delivery (CDD). In conclusion, our experiments provided evidence that intermittent administration of L-dopa, but not continuous delivery, and DR1/PKA/p-tau (ser396) activation played a critical role in the molecular and behavioural induction of LID in 6-OHDA-lesioned rats. In addition, LBM treatment prevented the development of LID by inhibiting the expression of DR1/PKA/p-tau, as well as PPEB mRNA in dyskintic rats. Scientific Reports 4 doi: 10.1038/srep07506
    Digitale ISSN: 2045-2322
    Thema: Allgemeine Naturwissenschaft
    Publiziert von Springer Nature
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    Evidence for acoustic communication among bottom foraging humpback whales (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-17
    Beschreibung: Humpback whales (Megaptera novaeangliae), a mysticete with a cosmopolitan distribution, demonstrate marked behavioural plasticity. Recent studies show evidence of social learning in the transmission of specific population level traits ranging from complex singing to stereotyped prey capturing behaviour. Humpback whales have been observed to employ group foraging techniques, however details on how individuals coordinate behaviour in these groups is challenging to obtain. This study investigates the role of a novel broadband patterned pulsed sound produced by humpback whales engaged in bottom-feeding behaviours, referred to here as a ‘paired burst’ sound. Data collected from 56 archival acoustic tag deployments were investigated to determine the functional significance of these signals. Paired burst sound production was associated exclusively with bottom feeding under low-light conditions, predominantly with evidence of associated conspecifics nearby suggesting that the sound likely serves either as a communicative signal to conspecifics, a signal to affect prey behaviour, or possibly both. This study provides additional evidence for individual variation and phenotypic plasticity of foraging behaviours in humpback whales and provides important evidence for the use of acoustic signals among foraging individuals in this species. Scientific Reports 4 doi: 10.1038/srep07508
    Digitale ISSN: 2045-2322
    Thema: Allgemeine Naturwissenschaft
    Publiziert von Springer Nature
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    Novel stable hard transparent conductors in TiO2-TiC system: Design materials from scratch (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-17
    Beschreibung: Two new ternary compounds in the TiO2-TiC system, Ti5C2O6 and Ti3C2O2, are reported for the first time based on ab initio evolutionary algorithm. Ti5C2O6 has a tube-structure in which sp1 hybridized carbon chains run through the lattice along the b-axis; while in the Ti3C2O2 lattice, double TiO6 polyhedral are separated by the non-coplanar sp2 hybridized hexagon graphite layers along the c-axis, forming a sandwich-like structure. At ambient conditions, the two compounds are found to be mechanically and dynamically stable and intrinsic transparent conductors with high hardness (about twice harder than the conventional transparent conducting oxides). These mechanical, electronic, and optical properties make Ti5C2O6 and Ti3C2O2 ternary compounds be promising robust, hard, transparent, and conductive materials. Scientific Reports 4 doi: 10.1038/srep07503
    Digitale ISSN: 2045-2322
    Thema: Allgemeine Naturwissenschaft
    Publiziert von Springer Nature
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    An Integrated Microfluidic Chip System for Single-Cell Secretion Profiling of Rare Circulating Tumor Cells (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-17
    Beschreibung: Genetic and transcriptional profiling, as well as surface marker identification of single circulating tumor cells (CTCs) have been demonstrated. However, quantitatively profiling of functional proteins at single CTC resolution has not yet been achieved, owing to the limited purity of the isolated CTC populations and a lack of single-cell proteomic approaches to handle and analyze rare CTCs. Here, we develop an integrated microfluidic system specifically designed for streamlining isolation, purification and single-cell secretomic profiling of CTCs from whole blood. Key to this platform is the use of photocleavable ssDNA-encoded antibody conjugates to enable a highly purified CTC population with 〈75 ‘contaminated’ blood cells. An enhanced poly-L-lysine barcode pattern is created on the single-cell barcode chip for efficient capture rare CTC cells in microchambers for subsequent secreted protein profiling. This system was extensively evaluated and optimized with EpCAM-positive HCT116 cells seeded into whole blood. Patient blood samples were employed to assess the utility of the system for isolation, purification and single-cell secretion profiling of CTCs. The CTCs present in patient blood samples exhibit highly heterogeneous secretion profile of IL-8 and VEGF. The numbers of secreting CTCs are found not in accordance with CTC enumeration based on immunostaining in the parallel experiments. Scientific Reports 4 doi: 10.1038/srep07499
    Digitale ISSN: 2045-2322
    Thema: Allgemeine Naturwissenschaft
    Publiziert von Springer Nature
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    From cells to muropeptide structures in 24 h: Peptidoglycan mapping by UPLC-MS (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-17
    Beschreibung: Peptidoglycan (PGN) is ubiquitous in nearly all bacterial species. The PGN sacculus protects the cells against their own internal turgor making PGN one of the most important targets for antibacterial treatment. Within the last sixty years PGN composition has been intensively studied by various methods. The breakthrough was the application of HPLC technology on the analysis of muropeptides. However, preparation of pure PGN relied on a very time consuming method of about one week. We established a purification protocol for both Gram-positive and Gram-negative bacteria which can be completely performed in plastic reaction tubes yielding pure muropeptides within 24 hours. The muropeptides can be analyzed by UPLC-MS, allowing their immediate determination. This new rapid method provides the feasibility to screen PGN composition even in high throughput, making it a highly useful tool for basic research as well as for the pharmaceutical industry. Scientific Reports 4 doi: 10.1038/srep07494
    Digitale ISSN: 2045-2322
    Thema: Allgemeine Naturwissenschaft
    Publiziert von Springer Nature
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    Superenhancers: Novel opportunities for nanowire optoelectronics (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-17
    Beschreibung: Nanowires play a crucial role in the development of new generation optoelectronic devices ranging from photovoltaics to photodetectors, as these designs capitalize on the low material usage, utilize leaky-mode optical resonances and possess high conversion efficiencies associated with nanowire geometry. However, their current schemes lack sufficient absorption capacity demanded for their practical applicability, and more efficient materials cannot find widespread usage in these designs due to their rarity and cost. Here we suggest a novel and versatile nanoconcentrator scheme utilizing unique optical features of non-resonant Mie (NRM) scattering regime associated with low-index structures. The scattering regime is highly compatible with resonant Mie absorption effect taking place in nanowire absorbers. This technique in its optimized forms can provide up to 1500% total absorption enhancement, 400-fold material save and is suitable for large-area applications with significant area preservation compared to thin-film of same materials. Proposed superenhancer concept with its exceptional features such as broadband absorption enhancement, polarization immunity and material-independent manner paves the way for development of efficient nanowire photosensors or solar thermophotovoltaic devices and presents novel design opportunities for self-powered nanosystems. Scientific Reports 4 doi: 10.1038/srep07505
    Digitale ISSN: 2045-2322
    Thema: Allgemeine Naturwissenschaft
    Publiziert von Springer Nature
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    Protonophore properties of hyperforin are essential for its pharmacological activity (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-17
    Beschreibung: Hyperforin is a pharmacologically active component of the medicinal plant Hypericum perforatum (St. John's wort), recommended as a treatment for a range of ailments including mild to moderate depression. Part of its action has been attributed to TRPC6 channel activation. We found that hyperforin induces TRPC6-independent H+ currents in HEK-293 cells, cortical microglia, chromaffin cells and lipid bilayers. The latter demonstrates that hyperforin itself acts as a protonophore. The protonophore activity of hyperforin causes cytosolic acidification, which strongly depends on the holding potential, and which fuels the plasma membrane sodium-proton exchanger. Thereby the free intracellular sodium concentration increases and the neurotransmitter uptake by Na+ cotransport is inhibited. Additionally, hyperforin depletes and reduces loading of large dense core vesicles in chromaffin cells, which requires a pH gradient in order to accumulate monoamines. In summary the pharmacological actions of the “herbal Prozac” hyperforin are essentially determined by its protonophore properties shown here. Scientific Reports 4 doi: 10.1038/srep07500
    Digitale ISSN: 2045-2322
    Thema: Allgemeine Naturwissenschaft
    Publiziert von Springer Nature
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    Carrier-dependent magnetic anisotropy of cobalt doped titanium dioxide (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-17
    Beschreibung: Using first-principles calculations, we predict that the magnetic anisotropy energy of Co-doped TiO2 sensitively depends on carrier accumulation. This magnetoelectric phenomenon provides a potential route to a direct manipulation of the magnetization direction in diluted magnetic semiconductor by external electric-fields. We calculate the band structures and reveal the origin of the carrier-dependent magnetic anisotropy energy in k-space. It is shown that the carrier accumulation shifts the Fermi energy, and consequently, regulates the competing contributions to the magnetic anisotropy energy. The calculations provide an insight to understanding this magnetoelectric phenomenon, and a straightforward way to search prospective materials for electrically controllable spin direction of carriers. Scientific Reports 4 doi: 10.1038/srep07496
    Digitale ISSN: 2045-2322
    Thema: Allgemeine Naturwissenschaft
    Publiziert von Springer Nature
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    1D Magnetic Materials of Fe3O4 and Fe with High Performance of Microwave Absorption Fabricated by Electrospinning Method (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-17
    Beschreibung: Fe3O4 and Fe nanowires are successfully fabricated by electrospinning method and reduction process. Wiry microstructures were achieved with the phase transformation from α-Fe2O3 to Fe3O4 and Fe by partial and full reduction, while still preserving the wire morphology. The diameters of the Fe3O4 and Fe nanowires are approximately 50–60 nm and 30–40 nm, respectively. The investigation of microwave absorption reveals that the Fe3O4 nanowires exhibit excellent microwave absorbing properties. For paraffin-based composite containing 50% weight concentration of Fe3O4 nanowires, the minimum reflection loss reaches −17.2 dB at 6.2 GHz with the matching thickness of 5.5 mm. Furthermore, the calculation shows that the modulus of the ratio between the complex permittivity and permeability |ε/μ| is far away from unity at the minimum reflection loss point, which is quite different from the traditional opinions. Scientific Reports 4 doi: 10.1038/srep07493
    Digitale ISSN: 2045-2322
    Thema: Allgemeine Naturwissenschaft
    Publiziert von Springer Nature
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    Demonstration of a refractometric sensor based on an optical micro-fiber three-beam interferometer (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-17
    Beschreibung: With diameter close to the wavelength of the guided light and high index contrast between the fiber and the surrounding, an optical micro-fiber shows a variety of interesting waveguiding properties, including widely tailorable optical confinement, strong evanescent fields and waveguide dispersion. Among various micro-fiber applications, optical sensing has been attracting increasing research interest due to its possibilities of realizing miniaturized fiber optic sensors with small footprint, high sensitivity, and low optical power consumption. Typical micro-fiber based sensing structures, including Michelson interferometer, Mach-Zenhder interferometer, Fabry-Perot interferometer, micro-fiber ring resonator, have been proposed. The sensitivity of these structures heavily related to the fraction of evanescent field outside micro-fiber. In this paper, we report the first theoretical and experimental study of a new type of refractometric sensor based on micro-fiber three-beam interferometer. Theoretical and experimental analysis reveals that the sensitivity is not only determined by the fraction of evanescent field outside the micro-fiber but also related to the values of interferometric arms. The sensitivity can be enhanced significantly when the effective lengths of the interferometric arms tends to be equal. We argue that this has great potential for increasing the sensitivity of refractive index detection. Scientific Reports 4 doi: 10.1038/srep07504
    Digitale ISSN: 2045-2322
    Thema: Allgemeine Naturwissenschaft
    Publiziert von Springer Nature
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    Molecular-like hierarchical self-assembly of monolayers of mixtures of particles (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-17
    Beschreibung: We present a technique that uses an externally applied electric field to self-assemble monolayers of mixtures of particles into molecular-like hierarchical arrangements on fluid-liquid interfaces. The arrangements consist of composite particles (analogous to molecules) which are arranged in a pattern. The structure of a composite particle depends on factors such as the relative sizes of the particles and their polarizabilities, and the electric field intensity. If the particles sizes differ by a factor of two or more, the composite particle has a larger particle at its core and several smaller particles form a ring around it. The number of particles in the ring and the spacing between the composite particles depend on their polarizabilities and the electric field intensity. Approximately same sized particles form chains (analogous to polymeric molecules) in which positively and negatively polarized particles alternate. Scientific Reports 4 doi: 10.1038/srep07427
    Digitale ISSN: 2045-2322
    Thema: Allgemeine Naturwissenschaft
    Publiziert von Springer Nature
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    Variability of the subtropical highs, African easterly jet and easterly wave intensities over North Africa and Arabian Peninsula in late summer (2014)
    Wiley
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    Publikationsdatum: 2014-12-18
    Beschreibung: ABSTRACT The North African climate is analysed for August during a 32-year period using the European Centre for Medium Range Weather Forecast (ECMWF) global data set to investigate the intensity variability at 600 mb of the subtropical highs, Africa easterly jet (AEJ) with two embedded local wind maxima, and African easterly waves over North Africa and the Arabian Peninsula. The variability of these synoptic weather systems is higher in East Africa. The most noticeable variability of intensity occurred with easterly waves. Maintenance of easterly waves from the Arabian Peninsula into East Africa is dependent on strong zonal gradients from the AEJ through shear vorticity. These zonal gradients were induced by the strengthening of the subtropical highs and the presence of a westerly jet in Central Africa and south of the Arabian Peninsula. During positive ENSO periods, these systems are generally weaker while in negative periods are stronger. The focus of this research is to investigate the role of the Arabian High and eastern local wind maximum (LWM E ) on complementing the Saharan High and western local wind maximum (LWM W ). It is found that an intense local wind maximum in East Africa helps maintain the easterly waves and their westward propagation from the Arabian Peninsula.
    Print ISSN: 0899-8418
    Digitale ISSN: 1097-0088
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley
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    Oceanic influence on the Baiu frontal zone in the East China Sea (2014)
    Wiley
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    Publikationsdatum: 2014-12-18
    Beschreibung: A high-resolution transect of atmospheric soundings across the Kuroshio Current in the East China Sea was conducted onboard a ship in June 2012 with the objective of analyzing the influence of the complex sea surface temperature (SST) distribution on the Baiu frontal zone (BFZ). Expendable bathythermograph castings and continuous surface meteorological observations were also examined. Two distinct mesoscale atmospheric fronts, characterized by changes of wind direction in the lower troposphere and surface air temperature (SAT), were found in the BFZ. One (northern) atmospheric front was observed around the SST front in relation to a warm water tongue extending from the Kuroshio. A high SST region around the northern atmospheric front enhances unstable near surface stratification and intensifies turbulent heat flux. They help modify the marine atmospheric boundary layer in the BFZ. The other (southern) atmospheric front was at the southern end of the BFZ. Intense evaporation over the Kuroshio and moisture transport by southerly winds were important in forming the conditionally unstable air masses in the lower troposphere of the BFZ.
    Print ISSN: 0148-0227
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley im Namen von American Geophysical Union (AGU).
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    Variability of stratospheric mean age of air and of the local effects of residual circulation and eddy mixing (2014)
    Wiley
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    Publikationsdatum: 2014-12-18
    Beschreibung: We analyze the variability of mean age of air (AoA) and of the local effects of the stratospheric residual circulation and eddy mixing on AoA within the framework of the isentropic zonal mean continuity equation. AoA for the period 1988–2013 has been simulated with the Lagrangian chemistry transport model CLaMS driven by ERA-Interim winds and diabatic heating rates. Model simulated AoA in the lower stratosphere shows good agreement with both in-situ observations and satellite observations from MIPAS (Michelson Interferometer for Passive Atmospheric Sounding), even regarding interannual variability and changes during the last decade. The interannual variability throughout the lower stratosphere is largely affected by the QBO-induced circulation and mixing anomalies, with year-to-year AoA changes of about 0.5 years. The decadal 2002–2012 change shows decreasing AoA in the lowest stratosphere, below about 450 K. Above, AoA increases in the NH and decreases in the SH. Mixing appears to be crucial for understanding AoA variability, with local AoA changes resulting from a close balance between residual circulation and mixing effects. Locally, mixing increases AoA at low latitudes (40S-40N) and decreases AoA at higher latitudes. Strongest mixing occurs below about 500 K, consistent with the separation between shallow and deep circulation branches. The effect of mixing integrated along the air parcel path, however, significantly increases AoA globally, except in the polar lower stratosphere. Changes of local effects of residual circulation and mixing during the last decade are supportive of a strengthening shallow circulation branch in the lowest stratosphere and a southward shifting circulation pattern above.
    Print ISSN: 0148-0227
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley im Namen von American Geophysical Union (AGU).
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    A stability dependent parametrization of transfer coefficients for momentum and heat over polar sea ice to be used in climate models (2014)
    Wiley
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    Publikationsdatum: 2014-12-18
    Beschreibung: The interaction between sea ice and atmosphere depends strongly on the near-surface transfer coefficients for momentum and heat. A parametrization of these coefficients is developed on the basis of an existing parametrization of drag coefficients for neutral stratification that accounts for form drag caused by the edges of ice floes and melt ponds. This scheme is extended to better account for the dependence of surface wind on limiting cases of high and low ice concentration and to include near-surface stability effects over open water and ice on form drag. The stability correction is formulated on the basis of stability functions from Monin-Obukhov similarity theory and also using the Louis concept with stability functions depending on thebulk Richardson numbers. Furthermore, a parametrization is proposed that includes the effect of edge related turbulence also on heat transfer coefficients. The parametrizations are available in different levels of complexity. The lowest level only needs sea ice concentration and surface temperature as input while the more complex level needs additional sea ice characteristics. An important property of our parametrization is that form drag caused by ice edges depends on the stability over both ice and water which is in contrast to the skin drag over ice. Results of the parametrization show that stability has a large impact on form drag and, thereby, determines the value of sea ice concentration for which the transfer coefficients reach their maxima. Depending on the stratification, these maxima can occur anywhere between ice concentrations of 20 and 80%.
    Print ISSN: 0148-0227
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley im Namen von American Geophysical Union (AGU).
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    Magnetic flux of progenitor stars sets gamma-ray burst luminosity and variability (2014)
    Oxford University Press
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    Publikationsdatum: 2014-12-18
    Beschreibung: Long-duration gamma-ray bursts (GRBs) are thought to come from the core collapse of Wolf–Rayet stars. Whereas their stellar masses M * have a rather narrow distribution, the population of GRBs is very diverse, with gamma-ray luminosities L spanning several orders of magnitude. This suggests the existence of a ‘hidden’ stellar variable whose burst-to-burst variation leads to a spread in L . Whatever this hidden variable is, its variation should not noticeably affect the shape of GRB light curves, which display a constant luminosity (in a time-average sense) followed by a sharp drop at the end of the burst seen with Swift /XRT. We argue that such a hidden variable is progenitor star's large-scale magnetic flux. Shortly after the core collapse, most of stellar magnetic flux accumulates near the black hole (BH) and remains there. The flux extracts BH rotational energy and powers jets of roughly a constant luminosity, L j . However, once BH mass accretion rate $\dot{M}$ falls below ~ L j / c 2 , the flux becomes dynamically important and diffuses outwards, with the jet luminosity set by the rapidly declining mass accretion rate, $L_{\rm j}\sim \dot{M}c^2$ . This provides a potential explanation for the sharp end of GRBs and the universal shape of their light curves. During the GRB, gas infall translates spatial variation of stellar magnetic flux into temporal variation of L j . We make use of the deviations from constancy in L j to perform stellar magnetic flux ‘tomography’. Using this method, we infer the presence of magnetized tori in the outer layers of progenitor stars for GRB 920513 and GRB 940210.
    Print ISSN: 0035-8711
    Digitale ISSN: 1365-2966
    Thema: Physik
    Publiziert von Oxford University Press
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    Blind foreground subtraction for intensity mapping experiments (2014)
    Oxford University Press
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    Publikationsdatum: 2014-12-18
    Beschreibung: We make use of a large set of fast simulations of an intensity mapping experiment with characteristics similar to those expected of the Square Kilometre Array in order to study the viability and limits of blind foreground subtraction techniques. In particular, we consider three different approaches: polynomial fitting, principal component analysis (PCA) and independent component analysis (ICA). We review the motivations and algorithms for the three methods, and show that they can all be described, using the same mathematical framework, as different approaches to the blind source separation problem. We study the efficiency of foreground subtraction both in the angular and radial (frequency) directions, as well as the dependence of this efficiency on different instrumental and modelling parameters. For well-behaved foregrounds and instrumental effects, we find that foreground subtraction can be successful to a reasonable level on most scales of interest. We also quantify the effect that the cleaning has on the recovered signal and power spectra. Interestingly, we find that the three methods yield quantitatively similar results, with PCA and ICA being almost equivalent.
    Print ISSN: 0035-8711
    Digitale ISSN: 1365-2966
    Thema: Physik
    Publiziert von Oxford University Press
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    Hot gas in massive haloes drives both mass quenching and environment quenching (2014)
    Oxford University Press
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    Publikationsdatum: 2014-12-18
    Beschreibung: Observed galaxies with high stellar masses or in dense environments have low specific star formation rates, i.e. they are quenched. Based on cosmological hydrodynamic simulations that include a prescription where quenching occurs in regions dominated by hot (〉10 5.4  K) gas, we argue that this hot gas quenching in haloes 〉10 12 M drives both mass quenching (i.e. central quenching) and environment quenching (i.e. satellite quenching). These simulations reproduce a broad range of locally observed trends among quenching, halo mass, stellar mass, environment, and distance to halo centre. Mass quenching is independent of environment because ~10 12 –10 13 M ‘mass quenching haloes’ inhabit a large range of environments. On the other hand, environment quenching is independent of stellar mass because galaxies of all stellar masses may live in dense environments as satellites of groups and clusters. As in observations, the quenched fraction of satellites increases with halo mass and decreases with distance to the centre of the group or cluster. We investigate pre-processing in group haloes, ejected former satellites, and hot gas that extends beyond the virial radius. The agreement of our model with key observational trends suggests that hot gas in massive haloes plays a leading role in quenching low-redshift galaxies.
    Print ISSN: 0035-8711
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    Thema: Physik
    Publiziert von Oxford University Press
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    Observations of hydroxyl in early-type galaxies (2014)
    Oxford University Press
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    Publikationsdatum: 2014-12-18
    Beschreibung: We used Arecibo Observatory and the Green Bank Telescope to observe OH in 12 early-type galaxies with known reservoirs of dense gas. We present three new detections of OH in absorption in the 1667 MHz line. One objective of our survey was to find evidence of molecular outflows, but our sensitivity and the strength of the OH absorption were insufficient to detect outflows. The detected sources have infrared luminosities and dust temperatures among the lowest of any galaxy detected in OH absorption. The ratio L HCN / L CO , a measure of the dense gas fraction in galaxies, is a powerful selector of OH megamasers for galaxies with high infrared luminosity. In early-type galaxies, which have much lower infrared luminosities, L HCN / L CO is also a promising tool for discovering OH, but in absorption rather than in maser emission. In addition to dense molecular gas, a radio continuum source and a favourable line of sight to the observer are likely key factors in detecting OH absorbers.
    Print ISSN: 0035-8711
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    Thema: Physik
    Publiziert von Oxford University Press
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    Propagation style controls lava–snow interactions (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-18
    Beschreibung: Article How volcanoes and the cryosphere interact is of interest for understanding hazard mitigation at ice-clad volcanoes and for paleoclimate studies. Here, the authors provide quantitative details from an eruption in Kamchatka, demonstrating that two kinds of lava, ′a′a and pahoehoe, produced different snowpack responses. Nature Communications doi: 10.1038/ncomms6666 Authors: B. R. Edwards, A. Belousov, M. Belousova
    Digitale ISSN: 2041-1723
    Thema: Biologie , Chemie und Pharmazie , Allgemeine Naturwissenschaft , Physik
    Publiziert von Springer Nature
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    Manifestation of unconventional biexciton states in quantum dots (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-18
    Beschreibung: Article Artificial atoms usually constitute an orbital structure for trapped charge carriers. Here, Hönig et al . demonstrate that polarization fields and large charge carrier masses can dilute the common orbital conception and find a hybrid-biexciton molecule that enables anomalous spin configurations. Nature Communications doi: 10.1038/ncomms6721 Authors: Gerald Hönig, Gordon Callsen, Andrei Schliwa, Stefan Kalinowski, Christian Kindel, Satoshi Kako, Yasuhiko Arakawa, Dieter Bimberg, Axel Hoffmann
    Digitale ISSN: 2041-1723
    Thema: Biologie , Chemie und Pharmazie , Allgemeine Naturwissenschaft , Physik
    Publiziert von Springer Nature
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    Bacteria can mobilize nematode-trapping fungi to kill nematodes (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-18
    Beschreibung: Article Certain soil fungi form specialized cellular structures or 'traps' to feed on nematodes, which in turn eat bacteria. Here, the authors show that urea released from bacteria induces trap formation in the fungi and this promotes nematode elimination. Nature Communications doi: 10.1038/ncomms6776 Authors: Xin Wang, Guo-Hong Li, Cheng-Gang Zou, Xing-Lai Ji, Tong Liu, Pei-Ji Zhao, Lian-Ming Liang, Jian-Ping Xu, Zhi-Qiang An, Xi Zheng, Yue-Ke Qin, Meng-Qing Tian, You-Yao Xu, Yi-Cheng Ma, Ze-Fen Yu, Xiao-Wei Huang, Shu-Qun Liu, Xue-Mei Niu, Jin-Kui Yang, Ying Huang, Ke-Qin Zhang
    Digitale ISSN: 2041-1723
    Thema: Biologie , Chemie und Pharmazie , Allgemeine Naturwissenschaft , Physik
    Publiziert von Springer Nature
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    Low-end mass function of the arches cluster (2014)
    Oxford University Press
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    Publikationsdatum: 2014-12-18
    Beschreibung: The initial mass function (IMF) of the Arches cluster, which was formed a few million years ago in the harsh environment of the Galactic Centre (GC), has long been a target of interest to those who study the GC and the theory of star formation. The distinct star-forming conditions in the GC might have caused the cluster to have a shallower slope or an elevated lower mass cutoff in its IMF. But its mass function (MF) has been revealed only down to 1–2 M (the lower limit of resolved stars), and the low-end MF of the Arches is still unknown. To estimate the unresolved part of the Arches MF, we have devised a novel photometric method that involves the histogram of pixel intensities in the observed image, which contains information on the unresolved, faint stars. By comparing the pixel intensity histograms (PIHs) of numerous artificial images constructed from model IMFs with the observed PIH, we find that the best-fitting model IMF for the Arches cluster has a cutoff mass less than or similar to 0.1 M and a shape very close to that of the Kroupa MF. Our findings imply that the IMF of the Arches cluster is similar to those found in the Galactic disc.
    Print ISSN: 0035-8711
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    Thema: Physik
    Publiziert von Oxford University Press
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    BMP signalling regulates the pre-implantation development of extra-embryonic cell lineages in the mouse embryo (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-18
    Beschreibung: Article BMP signalling is important in early post-implantation embryonic development. Here the authors perform mRNA sequencing of inside and outside cells of pre-implantation mouse embryos and show that BMP signalling is critical for the development of the two extra-embryonic lineages at this early stage. Nature Communications doi: 10.1038/ncomms6667 Authors: Sarah J. L. Graham, Krzysztof B. Wicher, Agnieszka Jedrusik, Guoji Guo, Wishva Herath, Paul Robson, Magdalena Zernicka-Goetz
    Digitale ISSN: 2041-1723
    Thema: Biologie , Chemie und Pharmazie , Allgemeine Naturwissenschaft , Physik
    Publiziert von Springer Nature
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    High quality-factor optical nanocavities in bulk single-crystal diamond (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-18
    Beschreibung: Article Single-crystal diamond is a promising material for applications in classical and quantum optics, but the lack of scalable fabrication remains an issue. Here, Burek et al . adapt angle-etching nanofabrication techniques to realize ring resonators and photonic crystal cavities in single crystal diamond with quality factors in excess of 10 5 . Nature Communications doi: 10.1038/ncomms6718 Authors: Michael J. Burek, Yiwen Chu, Madelaine S. Z. Liddy, Parth Patel, Jake Rochman, Srujan Meesala, Wooyoung Hong, Qimin Quan, Mikhail D. Lukin, Marko Lončar
    Digitale ISSN: 2041-1723
    Thema: Biologie , Chemie und Pharmazie , Allgemeine Naturwissenschaft , Physik
    Publiziert von Springer Nature
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    A dynamic supramolecular polymer with stimuli-responsive handedness for in situ probing of enzymatic ATP hydrolysis (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-18
    Beschreibung: Article Interesting changes in physical and optical properties can result from the binding of small molecules to supramolecular polymers. Here, the authors present an ATP assay, using a supramolecular helix to switch between left- and right-handed conformations on binding different adenosine phosphates. Nature Communications doi: 10.1038/ncomms6793 Authors: Mohit Kumar, Patrick Brocorens, Claire Tonnelé, David Beljonne, Mathieu Surin, Subi J. George
    Digitale ISSN: 2041-1723
    Thema: Biologie , Chemie und Pharmazie , Allgemeine Naturwissenschaft , Physik
    Publiziert von Springer Nature
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    Transposable element islands facilitate adaptation to novel environments in an invasive species (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-18
    Beschreibung: Article Genetic variation is key to species evolution. Here the authors sequence two phenotypically distinct populations of the ant Cardiocondyla obscurior , and find accumulations of transposable elements correlating with genetic variation that may have a role in differentiation, adaptation and speciation. Nature Communications doi: 10.1038/ncomms6495 Authors: Lukas Schrader, Jay W. Kim, Daniel Ence, Aleksey Zimin, Antonia Klein, Katharina Wyschetzki, Tobias Weichselgartner, Carsten Kemena, Johannes Stökl, Eva Schultner, Yannick Wurm, Christopher D. Smith, Mark Yandell, Jürgen Heinze, Jürgen Gadau, Jan Oettler
    Digitale ISSN: 2041-1723
    Thema: Biologie , Chemie und Pharmazie , Allgemeine Naturwissenschaft , Physik
    Publiziert von Springer Nature
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    A recoverable state of axon injury persists for hours after spinal cord contusion in vivo (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-18
    Beschreibung: Article A potential therapeutic strategy for spinal cord injury (SCI) is to maintain continuity of damaged axons after contusion, but the viability of such strategies depends on the degree to which initially injured axons can recover. Here the authors use morphological and molecular in vivo imaging after contusion SCI in mice, to show that injured axons persist in a metastable state for hours. Nature Communications doi: 10.1038/ncomms6683 Authors: Philip R. Williams, Bogdan-Nicolae Marincu, Catherine D. Sorbara, Christoph F. Mahler, Adrian-Minh Schumacher, Oliver Griesbeck, Martin Kerschensteiner, Thomas Misgeld
    Digitale ISSN: 2041-1723
    Thema: Biologie , Chemie und Pharmazie , Allgemeine Naturwissenschaft , Physik
    Publiziert von Springer Nature
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  • 90
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    An ecdysone-responsive nuclear receptor regulates circadian rhythms in Drosophila (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-18
    Beschreibung: Article The mammalian circadian clock is influenced by nuclear receptors such as Rev-Erb. Here Kumar et al . show that ecdysone-induced protein 75 (E75), a fly homologue of Rev-Erb, regulates circadian rhythms in Drosophila , and demonstrate that E75 protects the clock against environmental stressors. Nature Communications doi: 10.1038/ncomms6697 Authors: Shailesh Kumar, Dechun Chen, Christopher Jang, Alexandra Nall, Xiangzhong Zheng, Amita Sehgal
    Digitale ISSN: 2041-1723
    Thema: Biologie , Chemie und Pharmazie , Allgemeine Naturwissenschaft , Physik
    Publiziert von Springer Nature
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  • 91
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    Colloidal glasses: Sheared into two flows (2014)
    Springer Nature
    Details
    Publikationsdatum: 2014-12-18
    Beschreibung: Nature Materials 14, 13 (2015). doi:10.1038/nmat4189 Author: Pep Pàmies
    Print ISSN: 1476-1122
    Digitale ISSN: 1476-4660
    Thema: Chemie und Pharmazie , Maschinenbau , Allgemeine Naturwissenschaft , Physik
    Publiziert von Springer Nature
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    Material witness: The final cut (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-18
    Beschreibung: Nature Materials 14, 16 (2015). doi:10.1038/nmat4185 Author: Philip Ball
    Print ISSN: 1476-1122
    Digitale ISSN: 1476-4660
    Thema: Chemie und Pharmazie , Maschinenbau , Allgemeine Naturwissenschaft , Physik
    Publiziert von Springer Nature
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    Benzene-derived carbon nanothreads (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-18
    Beschreibung: Nature Materials 14, 43 (2015). doi:10.1038/nmat4088 Authors: Thomas C. Fitzgibbons, Malcolm Guthrie, En-shi Xu, Vincent H. Crespi, Stephen K. Davidowski, George D. Cody, Nasim Alem & John V. Badding Low-dimensional carbon nanomaterials such as fullerenes, nanotubes, graphene and diamondoids have extraordinary physical and chemical properties. Compression-induced polymerization of aromatic molecules could provide a viable synthetic route to ordered carbon nanomaterials, but despite almost a century of study this approach has produced only amorphous products. Here we report recovery to ambient pressure of macroscopic quantities of a crystalline one- dimensional sp3carbon nanomaterial formed by high-pressure solid-state reaction of benzene. X-ray and neutron diffraction, Raman spectroscopy, solid-state NMR, transmission electron microscopy and first-principles calculations reveal close- packed bundles of subnanometre-diameter sp3-bonded carbon threads capped with hydrogen, crystalline in two dimensions and short-range ordered in the third. These nanothreads promise extraordinary properties such as strength and stiffness higher than that of sp2carbon nanotubes or conven tional high-strength polymers. They may be the first member of a new class of ordered sp3 nanomaterials synthesized by kinetic control of high-pressure solid-state reactions.
    Print ISSN: 1476-1122
    Digitale ISSN: 1476-4660
    Thema: Chemie und Pharmazie , Maschinenbau , Allgemeine Naturwissenschaft , Physik
    Publiziert von Springer Nature
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  • 94
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    Re-entrant solidification in polymer–colloid mixtures as a consequence of competing entropic and enthalpic attractions (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-18
    Beschreibung: Nature Materials 14, 61 (2015). doi:10.1038/nmat4109 Authors: Lang Feng, Bezia Laderman, Stefano Sacanna & Paul Chaikin In polymer–colloid mixtures, non-adsorbing polymers dispersed with much larger colloids provide a universal yet specific entropic attraction between the colloids. Such so-called depletion interaction arises from an osmotic-pressure imbalance caused by the polymers and is considered to be independent of temperature. Here we show that, for the most commonly used polymer–colloid depletion systems, the polymer undergoes a crossover from non-adsorbing to adsorbing and that, consequently, the effective colloidal interactions depend on temperature. We also find that a combination of the enthalpic (polymer bridging) and entropic (polymer exclusion) interactions, both attractive, leads to a re-entrant regime where the colloids are dispersed and form solids both on heating and on cooling. We provide a simple model to explain the observed transitions and to fill the theoretical gap at the polymer-adsorption crossover. Our findings open possibilities for colloidal self-assembly, the formation of colloidal crystals and glasses, and the behaviour of temperature-controlled viscoelastic materials.
    Print ISSN: 1476-1122
    Digitale ISSN: 1476-4660
    Thema: Chemie und Pharmazie , Maschinenbau , Allgemeine Naturwissenschaft , Physik
    Publiziert von Springer Nature
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  • 95
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    Giant barocaloric effect enhanced by the frustration of the antiferromagnetic phase in Mn3GaN (2014)
    Springer Nature
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    Publikationsdatum: 2014-12-18
    Beschreibung: Nature Materials 14, 73 (2015). doi:10.1038/nmat4117 Authors: Daichi Matsunami, Asaya Fujita, Koshi Takenaka & Mika Kano
    Print ISSN: 1476-1122
    Digitale ISSN: 1476-4660
    Thema: Chemie und Pharmazie , Maschinenbau , Allgemeine Naturwissenschaft , Physik
    Publiziert von Springer Nature
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  • 96
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    A review of Stratospheric Sounding Unit radiance observations for climate trends and reanalyses (2014)
    Wiley
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    Publikationsdatum: 2014-12-18
    Beschreibung: Stratospheric Sounding Units (SSU) on the NOAA polar orbiting satellites measured infrared radiances in the 15 micron CO 2 band between late 1978 and mid-2006. From these radiances a time series of layer mean stratospheric temperatures has been derived by several groups. Discrepancies in these temperature analyses have been highlighted recently and efforts are now underway to resolve the differences between them. This paper is the Met Office response summarising the issues to be resolved in creating a climate data record from the different SSUs, including corrections for radiometric, spectroscopic and tidal differences. Calibration issues identified include the SSU space view anomaly and radiometric anomalies in the NOAA-9 observations. The spectroscopic correction required for changing pressures in the pressure modulator cells is also outlined. The most important correction for the time series is for the solar diurnal and semi-diurnal tides as the satellite overpass local times change. Comparisons with other stratospheric temperature trend analyses are made and the reasons for the differences discussed. The time series presented here show sustained drops in stratospheric temperatures at all levels after the El Chichon and Pinatubo eruptions but only small trends to lower temperatures between eruptions.
    Print ISSN: 0035-9009
    Digitale ISSN: 1477-870X
    Thema: Geographie , Physik
    Publiziert von Wiley
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  • 97
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    Buried Object Detection by Means of a Lp Banach-Space Inversion Procedure (2014)
    Wiley
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    Publikationsdatum: 2014-12-18
    Beschreibung: Electromagnetic inspection techniques are becoming powerful tools for buried object detection and subsurface prospection in several applicative fields, such as civil engineering and archeology. However, the nonlinearity and ill-posedness of the underlying inverse problem make the development of efficient imaging techniques a very challenging task. In the present paper, an algorithm based on a regularizing approach in L p Banach spaces is proposed for tackling such problems. The effectiveness of the approach is verified by means of numerical simulations in a noisy environment, aimed at evaluating the reconstruction capabilities with respect to the choice of several model parameters. The reported results show that, for small targets, the use of L p Banach spaces with 1 〈  p  〈 2 allows to obtain a better localization of different buried scatterers.
    Print ISSN: 0048-6604
    Digitale ISSN: 1944-799X
    Thema: Geologie und Paläontologie , Physik
    Publiziert von Wiley im Namen von American Geophysical Union (AGU).
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  • 98
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    High-order multi-moment constrained finite volume global shallow water model on the Yin-Yang grid (2014)
    Wiley
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    Publikationsdatum: 2014-12-18
    Beschreibung: A high-order global shallow water model on Yin-Yang grid has been developed by using the multi-moment constrained finite volume (MCV) method. Different from the traditional finite volume method, more degrees of freedom (DOFs) which are the values at the solution points within each mesh element are defined and updated in time. The time evolution equations for these point values are derived from a set constraint conditions in terms of the so-called multi-moment quantities, such as the point value (PV), the volume-integrated average (VIA) and derivative (DV). Different moments use different forms of equations which are all consistent with the shallow water equations, among which the VIA moment is computed from a finite volume formulation of flux form that guarantees the rigorous numerical conservation. A fourth-order formulation is devised with the third-order reconstruction built over each element using the DOFs locally available. A simple and orthogonal overset grid, the Yin-Yang grid, is used to represent the spherical geometry with quasi-uniform grid spacing. The resulting global shallow water model is attractive in algorithmic simplicity and computational efficiency. The model has been validated by widely used benchmark tests. The numerical results of the present model are competitive to most existing advanced models.
    Print ISSN: 0035-9009
    Digitale ISSN: 1477-870X
    Thema: Geographie , Physik
    Publiziert von Wiley
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  • 99
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    Incident light adjustable solar cell by periodic nanolens architecture (2014)
    Springer Nature
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    Publikationsdatum: 2014-11-06
    Beschreibung: Could nanostructures act as lenses to focus incident light for efficient utilization of photovoltaics? Is it possible, in order to avoid serious recombination loss, to realize periodic nanostructures in solar cells without direct etching in a light absorbing semiconductor? Here we propose and demonstrate a promising architecture to shape nanolenses on a planar semiconductor. Optically transparent and electrically conductive nanolenses simultaneously provide the optical benefit of modulating the incident light and the electrical advantage of supporting carrier transportation. A transparent indium-tin-oxide (ITO) nanolens was designed to focus the incident light-spectrum in focal lengths overlapping to a strong electric field region for high carrier collection efficiency. The ITO nanolens effectively broadens near-zero reflection and provides high tolerance to the incident light angles. We present a record high light-conversion efficiency of 16.0% for a periodic nanostructured Si solar cell. Scientific Reports 4 doi: 10.1038/srep06879
    Digitale ISSN: 2045-2322
    Thema: Allgemeine Naturwissenschaft
    Publiziert von Springer Nature
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    Efficient bi-allelic gene knockout and site-specific knock-in mediated by TALENs in pigs (2014)
    Springer Nature
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    Publikationsdatum: 2014-11-06
    Beschreibung: Pigs are ideal organ donors for xenotransplantation and an excellent model for studying human diseases, such as neurodegenerative disease. Transcription activator-like effector nucleases (TALENs) are used widely for gene targeting in various model animals. Here, we developed a strategy using TALENs to target the GGTA1, Parkin and DJ-1 genes in the porcine genome using Large White porcine fibroblast cells without any foreign gene integration. In total, 5% (2/40), 2.5% (2/80), and 22% (11/50) of the obtained colonies of fibroblast cells were mutated for GGTA1, Parkin, and DJ-1, respectively. Among these mutant colonies, over 1/3 were bi-allelic knockouts (KO), and no off-target cleavage was detected. We also successfully used single-strand oligodeoxynucleotides to introduce a short sequence into the DJ-1 locus. Mixed DJ-1 mutant colonies were used as donor cells for somatic cell nuclear transfer (SCNT), and three female piglets were obtained (two were bi-allelically mutated, and one was mono-allelically mutated). Western blot analysis showed that the expression of the DJ-1 protein was disrupted in KO piglets. These results imply that a combination of TALENs technology with SCNT can efficiently generate bi-allelic KO pigs without the integration of exogenous DNA. These DJ-1 KO pigs will provide valuable information for studying Parkinson's disease. Scientific Reports 4 doi: 10.1038/srep06926
    Digitale ISSN: 2045-2322
    Thema: Allgemeine Naturwissenschaft
    Publiziert von Springer Nature
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