Arbeitszeitflexibilisierung als Beschäftigungspolitisches Instrument - Wirkungen und Grenzen Neuer Arbeitszeitpolitik

"Konzepte einer 'Neuen Arbeitszeitpolitik' treten mit dem doppelten Anspruch auf, durch eine Individualisierung von Arbeitszeitregelungen arbeitsmarktpolitische Probleme lösen und darüber hinaus zur Humanisierung der Arbeit beitragen zu können. Selektivität und Realisierungschancen flexibler Arbeitszeitregelungen wurden bislang hauptsächlich unter technologischen Gesichtspunkten diskutiert. Demgegenüber verfolgt dieser Beitrag die Absicht, den sozialen und institutionellen Verhältnissen Rechnung zu tragen, die im Zuge einer Arbeitszeitflexibilisierung wirksam sind. Zu diesem Zweck wird zunächst eine qualifikations- und organisationssoziologische Perspektive gewählt, die es erlaubt, zu begründen, in welchem Verhältnis Einsatz und Nutzung von Arbeitskräften mit den betrieblichen Organisationserfordernissen stehen. Daran anknüpfend wird gezeigt, wie sich die betriebliche Nutzung von Arbeitskräften auf die Arbeitszeitstruktur auswirkt. Es lassen sich zwei Typen herauskristallisieren, die in einem Entsprechungsverhältnis zur betrieblichen Hierarchie stehen: Im unteren Statusbereich dominieren starre Zeitnormierungen, die einen kontorllierenden Zugriff auf die Arbeitsvorgänge ermöglichen. Vornehmlich im oberen Bereich der Betriebshierarchie sind flexible, selbstbestimmte Muster der Zeitverwendung verbreitet, die mit der Loyalität und Identifikation der hier Beschäftigten mit dem Organisationsziel korrespondieren. Wir interpretieren diesen Befund als betrieblich-organisatorische Formen der Lösung arbeitswirtschaftlicher Probleme, nämlich als Strategien der Externalisierung des Nutzungsrisikos von Arbeitsvermögen im unteren Statusbereich und dessen Internalisierung im oberen Bereich. Im darauffolgenden Schritt diskutieren wir einige Varianten der Arbeitszeitflexibilisierung auf ihre Ausformung hin, die sie aufgrund dieser arbeitswirtschaftlicher Strategien erfahren. Ergebnis dieser Diskussion ist die Wahrscheinlichkeit einer stark selektiven Wirkung der Arbeitszeitflexibilisierung. Diesen kontraintentionalen Effekt erwarten wir primär aufgrund der Zuordnung vornehmlich chronologisch flexibler Arbeitszeitvarianten zu höheren Statuspositionen und chronometrische Varianten zum Bereich restriktiver, konjunkturempfindlicher Arbeitsplätze. Daraus folgt ferner eine in der zeitlichen Dimension stärker als bisher wirksame Zuordnung bestimmter Arbeitskräftegruppen zu den betriebsinternen bzw. zu den überbetrieblichen Arbeitsmärkten. Darüber hinaus erwarten wir primär in den unteren Statusgruppen neben einem Schutzverlust eine Verdichtung der Arbeit. Diese negativen Folgelasten lassen sich um so schwieriger abbauen, als mit der Verbreitung der Arbeitszeitflexibilisierung auch die Individualisierung von Arbeitszeitvereinbarungen verbunden ist. Die Verlagerung von Arbeitszeitregelungen von der tariflichen auf die betriebliche Ebene macht eine staatliche und/oder gewerkschaftliche Schutzpolitik unter den gegebenen institutionellen Voraussetzungen der Interessenvertretung abhängig Beschäftigter nahezu unmöglich. Sollen die Vorzüge von flexiblen Arbeitszeitregelungen daher nicht vollständig preisgegeben werden, bedarf es neuer Formen der staatlichen, tariflichen und innerbetrieblichen Konfliktregelung in diesem Betrieb."Arbeitszeitpolitik, Arbeitszeitflexibilität, Beschäftigung, Betrieb - Organisation

A Fokker-Planck formalism for diffusion with finite increments and absorbing boundaries

Gaussian white noise is frequently used to model fluctuations in physical systems. In Fokker-Planck theory, this leads to a vanishing probability density near the absorbing boundary of threshold models. Here we derive the boundary condition for the stationary density of a first-order stochastic differential equation for additive finite-grained Poisson noise and show that the response properties of threshold units are qualitatively altered. Applied to the integrate-and-fire neuron model, the response turns out to be instantaneous rather than exhibiting low-pass characteristics, highly non-linear, and asymmetric for excitation and inhibition. The novel mechanism is exhibited on the network level and is a generic property of pulse-coupled systems of threshold units.Comment: Consists of two parts: main article (3 figures) plus supplementary text (3 extra figures

Regulated Nuclear Trafficking of rpL10A Mediated by NIK1 Represents a Defense Strategy of Plant Cells against Virus

The NSP-interacting kinase (NIK) receptor-mediated defense pathway has been identified recently as a virulence target of the geminivirus nuclear shuttle protein (NSP). However, the NIK1–NSP interaction does not fit into the elicitor–receptor model of resistance, and hence the molecular mechanism that links this antiviral response to receptor activation remains obscure. Here, we identified a ribosomal protein, rpL10A, as a specific partner and substrate of NIK1 that functions as an immediate downstream effector of NIK1-mediated response. Phosphorylation of cytosolic rpL10A by NIK1 redirects the protein to the nucleus where it may act to modulate viral infection. While ectopic expression of normal NIK1 or a hyperactive NIK1 mutant promotes the accumulation of phosphorylated rpL10A within the nuclei, an inactive NIK1 mutant fails to redirect the protein to the nuclei of co-transfected cells. Likewise, a mutant rpL10A defective for NIK1 phosphorylation is not redirected to the nucleus. Furthermore, loss of rpL10A function enhances susceptibility to geminivirus infection, resembling the phenotype of nik1 null alleles. We also provide evidence that geminivirus infection directly interferes with NIK1-mediated nuclear relocalization of rpL10A as a counterdefensive measure. However, the NIK1-mediated defense signaling neither activates RNA silencing nor promotes a hypersensitive response but inhibits plant growth and development. Although the virulence function of the particular geminivirus NSP studied here overcomes this layer of defense in Arabidopsis, the NIK1-mediated signaling response may be involved in restricting the host range of other viruses

Network-State Modulation of Power-Law Frequency-Scaling in Visual Cortical Neurons

Various types of neural-based signals, such as EEG, local field potentials and intracellular synaptic potentials, integrate multiple sources of activity distributed across large assemblies. They have in common a power-law frequency-scaling structure at high frequencies, but it is still unclear whether this scaling property is dominated by intrinsic neuronal properties or by network activity. The latter case is particularly interesting because if frequency-scaling reflects the network state it could be used to characterize the functional impact of the connectivity. In intracellularly recorded neurons of cat primary visual cortex in vivo, the power spectral density of Vm activity displays a power-law structure at high frequencies with a fractional scaling exponent. We show that this exponent is not constant, but depends on the visual statistics used to drive the network. To investigate the determinants of this frequency-scaling, we considered a generic recurrent model of cortex receiving a retinotopically organized external input. Similarly to the in vivo case, our in computo simulations show that the scaling exponent reflects the correlation level imposed in the input. This systematic dependence was also replicated at the single cell level, by controlling independently, in a parametric way, the strength and the temporal decay of the pairwise correlation between presynaptic inputs. This last model was implemented in vitro by imposing the correlation control in artificial presynaptic spike trains through dynamic-clamp techniques. These in vitro manipulations induced a modulation of the scaling exponent, similar to that observed in vivo and predicted in computo. We conclude that the frequency-scaling exponent of the Vm reflects stimulus-driven correlations in the cortical network activity. Therefore, we propose that the scaling exponent could be used to read-out the “effective” connectivity responsible for the dynamical signature of the population signals measured at different integration levels, from Vm to LFP, EEG and fMRI

What Is Stochastic Resonance? Definitions, Misconceptions, Debates, and Its Relevance to Biology

Stochastic resonance is said to be observed when increases in levels of unpredictable fluctuations—e.g., random noise—cause an increase in a metric of the quality of signal transmission or detection performance, rather than a decrease. This counterintuitive effect relies on system nonlinearities and on some parameter ranges being “suboptimal”. Stochastic resonance has been observed, quantified, and described in a plethora of physical and biological systems, including neurons. Being a topic of widespread multidisciplinary interest, the definition of stochastic resonance has evolved significantly over the last decade or so, leading to a number of debates, misunderstandings, and controversies. Perhaps the most important debate is whether the brain has evolved to utilize random noise in vivo, as part of the “neural code”. Surprisingly, this debate has been for the most part ignored by neuroscientists, despite much indirect evidence of a positive role for noise in the brain. We explore some of the reasons for this and argue why it would be more surprising if the brain did not exploit randomness provided by noise—via stochastic resonance or otherwise—than if it did. We also challenge neuroscientists and biologists, both computational and experimental, to embrace a very broad definition of stochastic resonance in terms of signal-processing “noise benefits”, and to devise experiments aimed at verifying that random variability can play a functional role in the brain, nervous system, or other areas of biology

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements