Intermediary Organisations and the Hegemonisation of Social Entrepreneurship: Fantasmatic Articulations, Constitutive Quiescences, and Moments of Indeterminacy

The rapid rise of alternative organisations such as social enterprises is largely due to the promotional activities of intermediary organisations. So far, little is known about the affective nature of such activities. The present article thus investigates how intermediary organisations make social entrepreneurship palatable for a broader audience by establishing it as an object of desire. Drawing on affect-oriented extensions of Laclau and Mouffe's poststructuralist theory, hegemonisation is suggested as a way of understanding how social entrepreneurship is articulated through a complementary process of signification and affective investment. Specifically, by examining Austrian intermediaries, we show how social entrepreneurship is endowed with a sense of affective thrust that is based on three interlocking dynamics: the articulation of fantasies such as 'inclusive exclusiveness', 'large-scale social change' and 'pragmatic solutions'; the repression of anxiety-provoking and contentious issues (constitutive quiescences); as well as the use of conceptually vague, floating signifiers (moments of indeterminacy). Demonstrating that the hegemonisation of social entrepreneurship involves articulating certain issues whilst, at the same time, omitting others, or rendering them elusive, the article invites a counter-hegemonic critique of social entrepreneurship, and, on a more general level, of alternative forms of organising, that embraces affect as a driving force of change, while simultaneously affirming the impossibility of harmony and wholeness

Breather solutions for a semilinear Klein–Gordon equation on a periodic metric graph

We consider the nonlinear Klein-Gordon equation $$\partial_t^2 u(x,t) - \partial_x^2 u(x,t) + \alpha u(x,t) = \pm |u(x,t)|^{p-1}u(x,t)$$ on a periodic metric graph (necklace graph) for $p > 1$ with Kirchhoff conditions at the vertices. Under suitable assumptions on the frequency we prove the existence and regularity of infinitely many spatially localized time-periodic solutions (breathers) by variational methods. We compare our results with previous results obtained via spatial dynamics and center manifold techniques. Moreover, we deduce regularity properties of the solutions and show that they are weak solutions of the corresponding initial value problem. Our approach relies on the existence of critical points for indefinite functionals, the concentration compactness principle, and the proper set-up of a functional analytic framework. Compared to earlier work for breathers using variational techniques, a major improvement of embedding properties has been achieved. This allows in particular to avoid all restrictions on the exponent $p > 1$ and to achieve higher regularity

Memristive operation mode of a site-controlled quantum dot floating gate transistor

The authors gratefully acknowledge financial support from the European Union (FPVII (2007-2013) under Grant Agreement No. 318287 Landauer) as well as the state of Bavaria.We have realized a floating gate transistor based on a GaAs/AlGaAs heterostructure with site-controlled InAs quantum dots. By short-circuiting the source contact with the lateral gates and performing closed voltage sweep cycles, we observe a memristive operation mode with pinched hysteresis loops and two clearly distinguishable conductive states. The conductance depends on the quantum dot charge which can be altered in a controllable manner by the voltage value and time interval spent in the charging region. The quantum dot memristor has the potential to realize artificial synapses in a state-of-the-art opto-electronic semiconductor platform by charge localization and Coulomb coupling.Publisher PDFPeer reviewe

SPHERES, J\"ulich's High-Flux Neutron Backscattering Spectrometer at FRM II

SPHERES (SPectrometer with High Energy RESolution) is a third-generation neutron backscattering spectrometer, located at the 20 MW German neutron source FRM II and operated by the Juelich Centre for Neutron Science. It offers an energy resolution (fwhm) better than 0.65 micro-eV, a dynamic range of +-31 micro-eV, and a signal-to-noise ratio of up to 1750:1.Comment: 12 pages, 7 figures, 2 tables. Supplemental material consists of 3 pages, 2 figures, 2 table

Associative learning with Y-shaped floating gate transistors operated in memristive modes

The authors gratefully acknowledge financial support from the European Union (FPVII (2007-2013) under grant agreement n° 318287 Landauer) as well as the state of Bavaria.We present Y-shaped three-terminal floating gate transistors with positioned quantum dots (QDs) acting as floating gates. The QDs are precisely positioned in the input terminals and the localized charge controls the conductance of the transistors. Connecting two devices enables to implement associative learning by tuning the QD-charge with two input signals. The number of pulses to develop or to forget the association depends on the widths and amplitudes of the applied voltage pulses. The Y-shaped geometry of the presented device may be considered to implement synaptic functionalities without separating learning and signal transmission in time.PostprintPeer reviewe

Electro-photo-sensitive memristor for neuromorphic and arithmetic computing

The authors gratefully acknowledge financial support from the European Union [FPVII (2007-2013) under Grant Agreement No. 318287 Landauer], as well as the state of Bavaria.We present optically and electrically tunable conductance modifications of a site-controlled quantum-dot memristor. The conductance of the device is tuned by electron localization on a quantum dot. The control of the conductance with voltage and low-power light pulses enables applications in neuromorphic and arithmetic computing. As in neural networks, applying pre- and postsynaptic voltage pulses to the memristor allows us to increase (potentiation) or decrease (depression) the conductance by tuning the time difference between the electrical pulses. Exploiting state-dependent thresholds for potentiation and depression, we are able to demonstrate a memory-dependent induction of learning. The discharging of the quantum dot can further be induced by low-power light pulses in the nanowatt range. In combination with the state-dependent threshold voltage for discharging, this enables applications as generic building blocks to perform arithmetic operations in bases ranging from binary to decimal with low-power optical excitation. Our findings allow the realization of optoelectronic memristor-based synapses in artificial neural networks with a memory-dependent induction of learning and enhanced functionality by performing arithmetic operations.PostprintPeer reviewe

Two-photon interference from remote quantum dots with inhomogeneously broadened linewidths

This work was financially supported by the German Ministry of Education and Research (BMBF) via the project QuaHL-Rep and by the State of Bavaria.In this paper, we study the influence of quasiresonant and nonresonant excitation on the interference properties of single photons emitted from quantum dots (QDs). The quasiresonant excitation scheme leads to an increase of interference visibility of photons emitted from the same QD to 69% compared to 12% for nonresonant excitation. Furthermore, we demonstrate quantum interference of photons emitted from separate QDs which are simultaneously excited into their p shell. We can readily extract a two-photon interference visibility as high as (39 ± 2)% for nonpostselected coincidences exceeding the predicted value based on coherence and radiative decay times of the quantum dot emission (similar to 25%). We account for this observation by treating the emission of both quantum dots as inhomogeneously broadened ensembles of Fourier-limited photons and observe good congruence between experiment and model.Publisher PDFPeer reviewe

Performance Characterization and Profiling of Chained CPU-bound Virtual Network Functions

The increased demand for high-quality Internet connectivity resulting from the growing number of connected devices and advanced services has put significant strain on telecommunication networks. In response, cutting-edge technologies such as Network Function Virtualization (NFV) and Software Defined Networking (SDN) have been introduced to transform network infrastructure. These innovative solutions offer dynamic, efficient, and easily manageable networks that surpass traditional approaches. To fully realize the benefits of NFV and maintain the performance level of specialized equipment, it is critical to assess the behavior of Virtual Network Functions (VNFs) and the impact of virtualization overhead. This paper delves into understanding how various factors such as resource allocation, consumption, and traffic load impact the performance of VNFs. We aim to provide a detailed analysis of these factors and develop analytical functions to accurately describe their impact. By testing VNFs on different testbeds, we identify the key parameters and trends, and develop models to generalize VNF behavior. Our results highlight the negative impact of resource saturation on performance and identify the CPU as the main bottleneck. We also propose a VNF profiling procedure as a solution to model the observed trends and test more complex VNFs deployment scenarios to evaluate the impact of interconnection, co-location, and NFV infrastructure on performance