1,398 research outputs found
Unternehmen, Organisationen und Werte
No full textDer Diskurs um Werte und Werthaltungen ist sowohl innerhalb des wirtschaftlichen und unternehmerischen Kontextes als auch im kirchlichen, theologischen und religionswissenschaftlichen Bereich ein aktuelles, kontrovers diskutiertes Thema. Anliegen des Sammelbandes ist es, eine Brücke zwischen Wissenschaft und Praxis, Betriebswirtschaftslehre, Religionswissenschaft und Theologie, Theorie und Empirie, Unternehmen und kirchlichen Organisationen sowie Lebenswelt und Religion zu schlagen. Der interdisziplinäre Ansatz versucht, durch eine vertiefte Auseinandersetzung mit der Wertethematik sowie durch einen multiperspektivischen Blick die oftmals komplexe wechselseitige Bezogenheit von Wirtschaft, Unternehmen, Werten und Religion differenzierter wahrzunehmen
Single channel properties of channelrhodopsin-2 determined by stationary noise analysis
No full textChannelrhodopsin-2, or ChR2, is a light-gated inward rectifying cation channel. Ever since its first characterisation (Nagel et al., 2003), it has been used extensively in the light-activated control of neural cells in culture as well as in living animals like mice, Caenorhabditis elegans and Drosophila melanagaster. Despite its broad application in the field of neuroscience, little is known about the properties of this ion channel. The aim of this thesis is to elucidate the single channel conductance under different conditions using stationary noise analysis on whole cell recordings of a HEK293 cell line that stably expresses the truncated ChR2 (amino acids 1-315), which behaves identically to the full length protein (Nagel et al., 2003). Stationary noise analysis is based on the fact that the ion channel noise due their opening and closing has a characteristic form of a plateau at low frequency points and a following decrease of power with 1/f² in difference power spectra, which are composed of the difference of fast Fourier transformed (FFT) stationary whole-cell recordings with and without illumination. From the parameters yielded by an approximation of the power spectra with a Lorentzian function the single channel conductance can be estimated. The single channel conductance of ChR2 was determined at -60 mV applied for different cations, yielding values of 91 ± 25 fS (Guanidine+), 42 ± 7 fS (Na+), 61 ± 18 fS (Li+) and 37 ± 14 fS (Methylammonium+). With 200 mM Guanidine+ outside of the cells and measurements between 0 mV and -60 mV applied, it could be shown that the inward rectification is still present on the scale of the single channel. Noise Analysis with concentrations between 40 and 200 mM Guanidine+ showed a saturation of the single channel conductance with high Guanidine+ concentrations with a maximal conduction of 129 ± 9 fS (Michaelis Menten approximation: Km = 82 ± 14 mM). Activation Energies of the rate constants k (2πfc, with fc = corner frequency of the Lorentzian function) and koff (1/τoff, with τoff = closing time of the channel at -60 mV) were determined to be 75 ± 23 kJ/mol and 64 ± 11 kJ/mol, respectively, which are similar to the value determined for the Channelrhodopsin-1 closing times (~60 kJ/mol; Nagel et al., 2002). The activation energy of the ChR2 single channel conductance was determined to be 21.2 ± 20.8 kJ/mol, which also is similar to the activation energy of the ChR1 current amplitude (20 kJ/mol; Nagel et al., 2002). The amount of active ChR2 channels in the membrane (160,000 or 226 ChR2/μm²) as well as the single channel current (-7.5 ± 0.6 fA) could be determined by variation of the light intensity (0.05 mW mm-2 to 5.3 mW mm-2). In the course of this thesis, the single channel parameters of the ChR2 mutant H134R were also determined. H134R had been previously published as a “gainof- function” mutant (Nagel et al., 2005a). The increased macroscopic current amplitude of H134R could be explained by an increased lifetime of the channel in comparison to the wildtype ChR2. Within the margin of error both single channel conductances in the presence of 200 mM Guanidine+ of the wildtype (91.1 ± 24.9 fS) and the H134R (89.4 ± 30.7 fS) are the same. In the presence of 200 mM Lithium+ values of 60.6 ± 17.8 fS for the wildtype ChR2 and 50.8 ± 9.6 fS for the H134R mutant were determined. This thesis marks the first in depth analysis of the single channel conductance of ChR2. Using stationary noise analysis the single channel conductance of Channelrhodopsin-1 as well as interesting Channelrhodopsin-2 mutants can also be analysed in the future.Channelrhodopsin-2, oder kurz ChR2, aus dem Augenfleck der Grünalge Chlamydomonas reinhardtii, ist ein lichtgesteuerter einwärts-gleichrichtender Ionenkanal, der monovalente Kationen leitet (Nagel et al., 2003). Das Maximum des Aktionsspektrums liegt bei ~460 nm. Der Photostrom von ChR2 ist auf die für die Familie der Rhodopsine typische 7-Transmembranregion beschränkt, was Messungen mit einem auf diesen Bereich verkürzten ChR2 möglich macht. Die typische Stromantwort der Kanäle unter patch clamp Bedingungen auf einen blauen Lichtstimulus besteht aus einem Peak und einer stationären Phase, die erst durch Abschalten des Lichtes beendet wird. Seit der ersten Beschreibung im Jahr 2003 durch Nagel et al. findet ChR2 eine breite Anwendung im Gebiet der Neurobiologie, da es eine lichtgesteuerte Depolarisierung von Neuronen in Kultur und im lebenden Organismus ermöglicht (z.B. Boyden et al., 2005; Li et al., 2005). So wurde ChR2 bereits in Mäusen und Ratten (z.B. Bi et al., 2006), Drosophila melanagaster (z.B. Schroll et al., 2006), Caenorhabditis elegans (z.B. Nagel et al., 2005b), Embryonen des Huhns (Li et al., 2005), und Zebrafischen (Douglass et al., 2008) exprimiert. Dennoch waren lange Zeit wichtige Eigenschaften des Kanals unbekannt. Mit der Beschreibung des Photozyklus (Bamann et al., 2008; Ritter et al., 2008) sowie Mutationen von Aminosäureresten, die in Bakteriorhodopsin eine essentielle Funktion haben (z.B. Nagel et al., 2005b), wurden wichtige Schritte zum Verständnis des Kanals gemacht. Jedoch ist bis heute die Einzelkanalleitfähigkeit nicht detailliert charakterisiert worden. Verschieden Schätzungen ergaben Werte von 50 fS (140 mM NaCl in der Badlösung; Nagel et al., 2003) und etwa 0,3 pS (6 mM K+ und 100 μM Ca2+; Harz et al., 1992). Zudem wurde kürzlich ein Wert von 1,1 pS publiziert (mit Einzelwerten im Bereich von 0,25 bis 2,42 pS (n=8); Lin et al., 2009). Dieser Wert wurde aus dem Bereich der Stromantwort des Kanals erworben in dem der Peakstrom in den stationären Bereich übergeht. Dieser Übergangs ist von der Lichtintensität und den Ausgangskonzentrationen des Licht- und Dunkelheits-adaptiereten Channelrhodopsin-2 abhängig und bisher kinetisch noch nicht ausreichend charakterisiert. Im Rahmen dieser Doktorarbeit wurde die Einzelkanalleitfähigkeit von Channelrhodopsin-2 mit Hilfe der stationären Rauschanalyse (z.B. DeFelice, 1981) untersucht: Das Öffnen und Schließen einer Population identischer Kanäle verbirgt sich in dem Rauschen um den mittleren Strom einer stationären Messung einer Zelle, die diese exprimiert. Dieses Kanalrauschen kann durch die Zerlegung dieses stationären Stromes in seine Frequenzanteile durch eine Fouriertransformation sichtbar gemacht werden. HEK293 Zellen, die Channelrhodopsin-2, bzw. ein ChR2 mit der Punktmutante H134R stabil exprimierten, wurden in der Ganzzellableitung der Patch Clamp Technik unter gekülten Bedingungen (11.5°C) vermessen. Zunächst wurde mit Hilfe von Spannungssprungprotollen das Umkehrpotential bei sättigenden Lichtverhältnissen bestimmt (473 nm), gefolgt von der Bestimmung des Punktes an dem die Amplitude der stationären Photoströme im Vergleich zu sättigenden Bedingungen halbiert war (jeweils bei -60 mV). Unter diesen halbmaximalen Lichtbedingungen wurden nun erneut das Umkehrpotential, sowie die Kanalschließzeit τoff bestimmt. Stationäre Aufnahmen (2 Minuten) abwechselnd ohne (3 Aufnahmen) und mit Beleuchtung (2 Aufnahmen) wurden in Folge aufgenommen, anschließend jeweils Fouriertransformiert und ein Differenzspektrum gebildet (die gemittelten Spektren mit Beleuchtung wurden von den gemittelten Spektren ohne Beleuchtung subtrahiert). ....
Observation of a(0)(0)(980)-f(0)(980) Mixing
No full textWe report the first observation of a(0)(0)(980)-f(0)(980) mixing in the decays of J/psi -> phi f(0)(980) -> phi a(0)(0)(980) -> phi eta pi(0) and chi(c1) -> a(0)(0)(980)pi(0) -> f(0)(980)pi(0)->pi(+)pi(-)pi(0), using data samples of 1.31 x 10(9) J/psi events and 4.48 x 10(8) psi (3686) events accumulated with the BESIII detector. The signals of f(0)(980) -> a(0)(0)(980) and a(0)(0)(980) -> f(0)(980) mixing are observed at levels of statistical significance of 7.4 sigma and 5.5 sigma, respectively. The corresponding branching fractions and mixing intensities are measured and the constraint regions on the coupling constants, g(a0K+K-) and g(f0K+K-), are estimated. The results improve the understanding of the nature of a(0)(0)(980) and f(0)(980)
Uncovering the research field of corporate social responsibility in family firms: a citation analysis
No full textPurposeInspired by increasing public interest in corporate social responsibility (CSR) and the intensified focus of research on family firms (FFs) over the past few decades, the purpose of this paper is to analyze the existing literature on CSR in FF through a citation analysis.Design/methodology/approachThis paper overviews the structure of research on CSR in FF, identifying influential publications, authors, and key lines of discussion. The authors identified the underlying sample through a systematic, keyword-based literature search of seven databases. Starting with this sample, the authors analyzed a database of 4,342 references of 3,025 different sources cited in the 63 articles.FindingsThe findings show that the cited literature on CSR in FF is widespread, confirming that the research field has great heterogeneity. The authors identified the most-cited researcher as Luis R. Gómez-Mejía (University of Notre Dame, USA), with 93 citations. The average author in the group of the 22 most-cited authors (with a three-way tie for 20th-most-cited author) counts 45.45 citations in the sample of 13.95 different sources. Because the citations mostly refer to journal articles, the authors further investigated the particular journals of publication. The 20 most-influential journals cover 45.28 percent of all citations, with theJournal of Business Ethicsbeing the most influential (6.38 percent of all citations). Within the 3,025 different sources cited in the whole sample, the publication by Dyer and Whetten (2006), which is titled “Family firms and social responsibility: preliminary evidence from the S&P 500,” is the most-cited (29 citations in 46.03 percent of the analyzed 63 peer-reviewed journal articles).Originality/valueThe authors conclude with a call for more research on CSR in FF (especially qualitative case studies). Moreover, as scholars of North America and Western Europe dominate the current landscape of research, the authors would like to encourage scholars from other countries and cultures to provide insights from their countries.</jats:sec
First testbeam measurements with a multi-layered septup of MuPix8 sensorts for the PANDA luminosity detector
No full textAuthor Correction:SciPy 1.0: fundamental algorithms for scientific computing in Python (Nature Methods, (2020), 10.1038/s41592-019-0686-2)
No full textIn the version of this article initially published online, the corresponding author designation was missing for Matt Haberland and Tyler Reddy. The affiliation for Evgeni Burovski was given as Higher School of Economics; the correct affiliation is National Research University, Higher School of Economics. In Box 1, “SciPy is an open-source package that builds on the strengths of Python and Numeric, providing a wide range of fast scientific and numeric functionality” was used as the box title; this has been moved to the beginning of the box text and a new title has been provided: “Excerpt from the SciPy 0.1 release announcement (typos corrected), posted 20 August 2001 on the Python-list mailing list.” From the original first sentence of this box, “(text following the % symbol indicates that a typo in the original text has been corrected in the version reproduced here)” has been deleted, and “% hanker to Hankel” and “% Netwon to Newton” have been deleted from the ends of the special functions row and the optimization row, respectively. In the first sentence of the ndimage section of Box 2, “nonlinear filter” has been changed to plural. At the end of the first paragraph of the section “SciPy matures,” “The library was expanded carefully, with the patience affordable in open-source projects and via best practices common in industry” has been changed to “The library was expanded carefully, with the patience affordable in open-source projects and via best practices, which are increasingly common in the scientific Python ecosystem and industry.” In Table 2, “Inequality constraint” has been changed to plural. In the “Nonlinear optimization: global minimization” section, “scipy.optimize.differentialevolution” had been changed to “scipy.optimize.differential_evolution.” In the first sentence of the section “Maintainers and contributors,” “SciPy developer guide” has been changed to “SciPy contributor guide” and the URL has been changed from http://scipy.github.io/devdocs/dev/core-dev/index. html to https://scipy.github.io/devdocs/dev/contributor/contributor_toc.html. In Table 2, entries in the first column have been changed from capitalized to lower-case. Finally, a URL in the second paragraph of the Discussion has been changed from https://scholar.google. com/scholar?q=SciPy to https://scholar.google.com/scholar?cites=2086009121748039507. The errors have been corrected in the print, HTML and PDF versions of the article. SciPy 1.0 Contributors Aditya Vijaykumar, Alessandro Pietro Bardelli, Alex Rothberg, Andreas Hilboll, Andreas Kloeckner, Anthony Scopatz, Antony Lee, Ariel Rokem, C. Nathan Woods, Chad Fulton, Charles Masson, Christian Häggström, Clark Fitzgerald, David A. Nicholson, David R. Hagen, Dmitrii V. Pasechnik, Emanuele Olivetti, Eric Martin, Eric Wieser, Fabrice Silva, Felix Lenders, Florian Wilhelm, G. Young, Gavin A. Price, Gert-Ludwig Ingold, Gregory E. Allen, Gregory R. Lee, Hervé Audren, Irvin Probst, Jörg P. Dietrich, Jacob Silterra, James T Webber, Janko Slavič, Joel Nothman, Johannes Buchner, Johannes Kulick, Johannes L. Schönberger, José Vinícius de Miranda Cardoso, Joscha Reimer, Joseph Harrington, Juan Luis Cano Rodríguez, Juan Nunez-Iglesias, Justin Kuczynski, Kevin Tritz, Martin Thoma, Matthew Newville, Matthias Kümmerer, Maximilian Bolingbroke, Michael Tartre, Mikhail Pak, Nathaniel J. Smith, Nikolai Nowaczyk, Nikolay Shebanov, Oleksandr Pavlyk, Per A. Brodtkorb, Perry Lee, Robert T. McGibbon, Roman Feldbauer, Sam Lewis, Sam Tygier, Scott Sievert, Sebastiano Vigna, Stefan Peterson, Surhud More, Tadeusz Pudlik, Takuya Oshima, Thomas J. Pingel, Thomas P. Robitaille, Thomas Spura, Thouis R. Jones, Tim Cera, Tim Leslie, Tiziano Zito, Tom Krauss, Utkarsh Upadhyay, Yaroslav O. Halchenko and Yoshiki Vázquez-Baeza.</p
Optogenetic long-term manipulation of behavior and animal development
No full textChannelrhodopsin-2 (ChR2) is widely used for rapid photodepolarization of neurons, yet, as it requires high-intensity blue light for activation, it is not suited for long-term in vivo applications, e.g. for manipulations of behavior, or photoactivation of neurons during development. We used “slow” ChR2 variants with mutations in the C128 residue, that exhibit delayed off-kinetics and increased light sensitivity in Caenorhabditis elegans. Following a 1 s light pulse, we could photodepolarize neurons and muscles for minutes (and with repeated brief stimulation, up to days) with low-intensity light. Photoactivation of ChR2(C128S) in command interneurons elicited long-lasting alterations in locomotion. Finally, we could optically induce profound changes in animal development: Long-term photoactivation of ASJ neurons, which regulate larval growth, bypassed the constitutive entry into the “dauer” larval state in daf-11 mutants. These lack a guanylyl cyclase, which possibly renders ASJ neurons hyperpolarized. Furthermore, photostimulated ASJ neurons could acutely trigger dauer-exit. Thus, slow ChR2s can be employed to long-term photoactivate behavior and to trigger alternative animal development
Study of light scalar mesons through Ds+ →π0π0e+νe and KS0 KS0 e+νe decays
No full textUsing 6.32 fb(-1) of e(+)e(-) collision data recorded by the BESIII detector at center-of-mass energies between 4.178 to 4.226 GeV, we present the first measurement of the decay D-s(+) -> f(0)(980)e(+)nu(e), f(0)(980) -> pi(0)pi(0). The product branching fraction of D-s(+) -> f(0)(980)e(+)nu(e), f(0)(980) -> pi(0)pi(0) is measured to be (7.9 +/- 1.4(stat) +/- 0.4(syst)) x 10(-4), with a statistical significance of 7.8 sigma. Furthermore, the upper limits on the product branching fractions of D-s(+) -> f(0)(500)e(+)nu(e) with f(0)(500) -> pi(0)pi(0) and the branching fraction of D-s(+) -> K(S)(0)K(S)(0)e(+)nu(e) are set to be 7.3 x 10(-4) and 3.8 x 10(-4) at 90% confidence level, respectively. Our results provide valuable inputs to the understanding of the structures of light scalar mesons
The AEMON-J “Hacking Limnology” Workshop Series & Virtual Summit: Incorporating Data Science and Open Science in Aquatic Research
No full textFollowing the 2020 “Virtual Summit: Incorporating Data Science and Open Science in Aquatic Research” (DSOS; Meyer and Zwart 2020), a grassroots group of scientists convened the 2nd Virtual DSOS Summit on 22–23 July 2021. DSOS combined forces with the Aquatic Ecosystem MOdeling Network - Junior (AEMON-J; https://github.com/aemon-j) to host a 4-d “Hacking Limnology” Workshop Series prior to the summit (13–16 July 2021). The aim was to focus more deeply on skill development and networking among early career researchers (ECRs), both of which are key to growing a workforce of data-intensive aquatic scientists (López Moreira M et al. in press; Meyer et al. 2021a). To support ECRs further, we hosted a virtual job board, where participants could note if they were either looking for employment or hiring for a position. Like the 2020 summit, there was high enthusiasm for both the summit and the workshops. In total, 686 people from over 50 countries registered for the AEMON-J Workshop Series and the DSOS Summit. Countries with the highest number of registrants included the United States (41%), Nigeria (20%), Canada (6%), Brazil (6%), and Germany (5%) (Fig. 1). To increase accessibility, there were no registration costs for the workshops and summit, and we centralized introductory training materials, coding scripts, and presentation recordings in one community website (https://aquaticdatasciopensci.github.io/; Fig. 2), which we hope will continue to support the AEMON-J and DSOS communities over time
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