High power 405 nm diode laser fiber-coupled single-mode system with high long-term stability

Fiber-coupled 405 nm diode laser systems are rarely used with fiber output powers higher than 50 mW. A quick degradation of fiber-coupled high power modules with wavelengths in the lower range of the visible spectrum is known for several years. Meanwhile, the typical power of single-mode diode lasers around 400 nm is in the order of 100 to 300 mW, leading to single-mode fiber core power densities in the 1 MW/cm² range. This is three magnitudes of order below the known threshold for optical damage. Our profound investigations on the influence of 405 nm laser light irradiation of single-mode fibers found the growth of periodic surface structures in the form of ripples responsible for the power loss. The ripples are found on the proximal and distal fiber end surfaces, negatively impacting power transmission and beam quality, respectively. Important parameters in the generation of the surface structures are power density, surface roughness and polarization direction. A fiber-coupled high-power 405 nm diode laser system with a high long-term stability will be introduced and described

Characteristics of light charged particle emission in the ternary fission of 250Cf and 252Cf at different excitation energies

The emission probabilities and the energy distributions of tritons, α and ^6He particles emitted in the spontaneous ternary fission (zero excitation energy) of ^250Cf and ^252Cf and in the cold neutron induced fission (excitation energy ≈ 6.5 MeV) of ^249Cf and 251Cf are determined. The particle identification was done with suited ΔE-E telescope detectors, at the IRMM (Geel, Belgium) for the spontaneous fission and at the ILL (Grenoble, France) for the neutron induced fission measurements. Hence particle emission characteristics of the fissioning systems ^250Cf and ^252Cf are obtained at zero and at about 6.5 MeV excitation energies. While the triton emission probability is hardly influenced by the excitation energy, the ^4He and ^6He emission probability in spontaneous fission is higher than for neutron induced fission. This can be explained by the strong influence of the cluster preformation probability on the ternary particle emission probability

Die soziale Lage von Film- und Fernsehschauspieler/innen in Deutschland

Der vorliegende Beitrag beschreibt die soziale Lage der Film- und Fernsehschauspieler/innen in Deutschland. Anhand der Daten einer quantitativen Befragung von Mitgliedern des Berufsverbands der Film- und Fernsehschauspieler/innen (BFFS) werden die Beschäftigungs- und Einkommenssituation, die Lebenszufriedenheit und die Einbindung in die Arbeitslosenversicherung analysiert. Vor dem Hintergrund der sich in den Ergebnissen der Analyse abzeichnenden problematischen Einbindung in die Arbeitslosenversicherung wird abschließend die allgemeine Integration der Wissens- und Kreativarbeitenden in das System der gesetzlichen Sozialversicherungen diskutiert.This article describes the social situation of movie and TV actors and actresses. Using data of a survey on members of the German association of film and TV actors and actresses (BFFS) we are analyzing their employment and income situation, their life satisfaction and their integration into the unemployment insurance. The results of the analysis concerning the integration into the unemployment insurance are discussed as an example for the general mismatch between the structure of the German social security system and the employment patterns of knowledge workers and creative professionals

RNAi Trigger Delivery into Anopheles gambiae Pupae

Citation: Regna, K., Harrison, R. M., Heyse, S. A., Chiles, T. C., Michel, K., & Muskavitch, M. A. T. (2016). RNAi Trigger Delivery into Anopheles gambiae Pupae. Jove-Journal of Visualized Experiments(109), 9. doi:10.3791/53738RNA interference (RNAi), a naturally occurring phenomenon in eukaryotic organisms, is an extremely valuable tool that can be utilized in the laboratory for functional genomic studies. The ability to knockdown individual genes selectively via this reverse genetic technique has allowed many researchers to rapidly uncover the biological roles of numerous genes within many organisms, by evaluation of loss-of-function phenotypes. In the major human malaria vector Anopheles gambiae, the predominant method used to reduce the function of targeted genes involves injection of double-stranded (dsRNA) into the hemocoel of the adult mosquito. While this method has been successful, gene knockdown in adults excludes the functional assessment of genes that are expressed and potentially play roles during pre-adult stages, as well as genes that are expressed in limited numbers of cells in adult mosquitoes. We describe a method for the injection of Serine Protease Inhibitor 2 (SRPN2) dsRNA during the early pupal stage and validate SRPN2 protein knockdown by observing decreased target protein levels and the formation of melanotic pseudo-tumors in SRPN2 knockdown adult mosquitoes. This evident phenotype has been described previously for adult stage knockdown of SRPN2 function, and we have recapitulated this adult phenotype by SRPN2 knockdown initiated during pupal development. When used in conjunction with a dye-labeled dsRNA solution, this technique enables easy visualization by simple light microscopy of injection quality and distribution of dsRNA in the hemocoel

Classic McEliece Implementation with Low Memory Footprint

The Classic McEliece cryptosystem is one of the most trusted quantum-resistant cryptographic schemes. Deploying it in practical applications, however, is challenging due to the size of its public key. In this work, we bridge this gap. We present an implementation of Classic McEliece on an ARM Cortex-M4 processor, optimized to overcome memory constraints. To this end, we present an algorithm to retrieve the public key ad-hoc. This reduces memory and storage requirements and enables the generation of larger key pairs on the device. To further improve the implementation, we perform the public key operation by streaming the key to avoid storing it as a whole. This additionally reduces the risk of denial of service attacks. Finally, we use these results to implement and run TLS on the embedded device

On the Decoding Failure Rate of QC-MDPC Bit-Flipping Decoders

International audienceQuasi-cyclic moderate density parity check codes allow the design of McEliece-like public-key encryption schemes with compact keys and a security that provably reduces to hard decoding problems for quasi-cyclic codes.In particular, QC-MDPC are among the most promising code-based key encapsulation mechanisms (KEM) that are proposed to the NIST call for standardization of quantum safe cryptography (two proposals, BIKE and QC-MDPC KEM).The first generation of decoding algorithms suffers from a small, but not negligible, decoding failure rate (DFR in the order of 10⁻⁷ to 10⁻¹⁰). This allows a key recovery attack presented by Guo, Johansson, and Stankovski (GJS attack) at Asiacrypt 2016 which exploits a small correlation between the faulty message patterns and the secret key of the scheme, and limits the usage of the scheme to KEMs using ephemeral public keys. It does not impact the interactive establishment of secure communications (e.g. TLS), but the use of static public keys for asynchronous applications (e.g. email) is rendered dangerous.Understanding and improving the decoding of QC-MDPC is thus of interest for cryptographic applications. In particular, finding parameters for which the failure rate is provably negligible (typically as low as 2⁻⁶⁴ or 2⁻¹²⁸) would allow static keys and increase the applicability of the mentioned cryptosystems.We study here a simple variant of bit-flipping decoding, which we call step-by-step decoding. It has a higher DFR but its evolution can be modeled by a Markov chain, within the theoretical framework of Julia Chaulet's PhD thesis. We study two other, more efficient, decoders. One is the textbook algorithm. The other is (close to) the BIKE decoder. For all those algorithms we provide simulation results, and, assuming an evolution similar to the step-by-step decoder, we extrapolate the value of the DFR as a function of the block length. This will give an indication of how much the code parameters must be increased to ensure resistance to the GJS attack

Efficient implementation of a CCA2-secure variant of McEliece using generalized Srivastava codes

International audienceIn this paper we present efficient implementations of McEliece variants using quasi-dyadic codes. We provide secure parameters for a classical McEliece encryption scheme based on quasi-dyadic generalized Srivastava codes, and successively convert our scheme to a CCA2-secure protocol in the random oracle model applying the Fujisaki-Okamoto transform. In contrast with all other CCA2-secure code-based cryptosystems that work in the random oracle model, our conversion does not require a constant weight encoding function. We present results for both 128-bit and 80-bit security level, and for the latter we also feature an implementation for an embedded device

Deep sleep maintains learning efficiency of the human brain

It is hypothesized that deep sleep is essential for restoring the brain's capacity to learn efficiently, especially in regions heavily activated during the day. However, causal evidence in humans has been lacking due to the inability to sleep deprive one target area while keeping the natural sleep pattern intact. Here we introduce a novel approach to focally perturb deep sleep in motor cortex, and investigate the consequences on behavioural and neurophysiological markers of neuroplasticity arising from dedicated motor practice. We show that the capacity to undergo neuroplastic changes is reduced by wakefulness but restored during unperturbed sleep. This restorative process is markedly attenuated when slow waves are selectively perturbed in motor cortex, demonstrating that deep sleep is a requirement for maintaining sustainable learning efficiency

Medical Records-Based Postmarketing Safety Evaluation of Rare Events with Uncertain Status

We develop a simple statistic for comparing rates of rare adverse events between treatment groups in post-marketing safety studies where the events have uncertain status. In this setting, the statistic is asymptotically equivalent to the logrank statistic, but the limiting distribution has Poisson and binomial components instead of being Guassian. We develop two new procedures for computing critical values, a Gaussian approximation and a parametric bootstrap. Both numerical and asymptotic properties of the procedures are studied. The test procedures are demonstrated on a post-marketing safety study of the RotaTeq vaccine. This vaccine was developed to reduce the incidence of severe diarrhea in infants

FASTER: Facilitating Analysis and Synthesis Technologies for Effective Reconfiguration

The FASTER (Facilitating Analysis and Synthesis Technologies for Effective Reconfiguration) EU FP7 project, aims to ease the design and implementation of dynamically changing hardware systems. Our motivation stems from the promise reconfigurable systems hold for achieving high performance and extending product functionality and lifetime via the addition of new features that operate at hardware speed. However, designing a changing hardware system is both challenging and time-consuming. FASTER facilitates the use of reconfigurable technology by providing a complete methodology enabling designers to easily specify, analyze, implement and verify applications on platforms with general-purpose processors and acceleration modules implemented in the latest reconfigurable technology. Our tool-chain supports both coarse- and fine-grain FPGA reconfiguration, while during execution a flexible run-time system manages the reconfigurable resources. We target three applications from different domains. We explore the way each application benefits from reconfiguration, and then we asses them and the FASTER tools, in terms of performance, area consumption and accuracy of analysis