Phase Change Material Device for Spacecraft Thermal Control

On board a satellite, the experiments and subsystems have to be maintained within specified temperature limits. Phase Change Materials (PCM) offer the possibility to store thermal energy directly as latent heat of fusion. Usually, the melting PCM can easily be used in reversible, closed systems. Two advantages of a PCM device are the stability of temperature control and the absence of moving parts. The heat-storage requirement is mainly defined by the duty cycle along the orbital period. A trade-off is presented for typical missions, which takes into account the temperature range, the weight and thermal conductivity of the PCM device together with the specific design of the container. Candidates PCM for space applications are reviewed according to their main characteristics such as latent heat, phase transition temperature, conductivity, density but also corrosion potential, hysteresis and ageing. Potential weight and power gains are finally presented for selected missions

MetaAdvDet: Towards Robust Detection of Evolving Adversarial Attacks

Deep neural networks (DNNs) are vulnerable to adversarial attack which is maliciously implemented by adding human-imperceptible perturbation to images and thus leads to incorrect prediction. Existing studies have proposed various methods to detect the new adversarial attacks. However, new attack methods keep evolving constantly and yield new adversarial examples to bypass the existing detectors. It needs to collect tens of thousands samples to train detectors, while the new attacks evolve much more frequently than the high-cost data collection. Thus, this situation leads the newly evolved attack samples to remain in small scales. To solve such few-shot problem with the evolving attack, we propose a meta-learning based robust detection method to detect new adversarial attacks with limited examples. Specifically, the learning consists of a double-network framework: a task-dedicated network and a master network which alternatively learn the detection capability for either seen attack or a new attack. To validate the effectiveness of our approach, we construct the benchmarks with few-shot-fashion protocols based on three conventional datasets, i.e. CIFAR-10, MNIST and Fashion-MNIST. Comprehensive experiments are conducted on them to verify the superiority of our approach with respect to the traditional adversarial attack detection methods.Comment: 10 pages, 2 figures, accepted as the conference paper of Proceedings of the 27th ACM International Conference on Multimedia (MM'19

Hacia la reutilización sustentable de residuos avícolas: evaluación integrada como enmienda orgánica

Poster y resumenLos residuos de la producción avícola (guano de gallinas ponedoras y cama de pollos de engorde) se han utilizado como fertilizantes o enmiendas orgánicas para disminuir el impacto y degradación que causan en los suelos la aplicación de fertilizantes químicos a largo plazo. Sin embargo, pocos estudios han evaluado condiciones de campo contrastantes donde estos residuos se hayan utilizado durante períodos prolongados de tiempo en sistemas de cultivos agrícolas. En este estudio se utilizaron parámetros fisicoquímicos, metabarcoding del gen ARNr 16S e índices de ecotoxicidad para caracterizar el guano de gallinas ponedoras y la cama de pollos de engorde y examinar el efecto de su aplicación en suelos agrícolas durante un período de 10 años (campos sometidos a rotación trigo/soja-maíz, utilizándose tres tratamientos: suelo control sin enmienda añadida, suelo + guano de ponedoras, suelo + cama de pollos). Los residuos avícolas mostraron altas concentraciones de nutrientes (N y P) y una alta conductividad eléctrica, lo que provocó efectos fitotóxicos al evaluar tanto la germinación de semillas como el alargamiento de la radícula de cinco especies vegetales (lechuga: Lactuca sativa variedad "Gallega", rabanito: Raphanus sativus variedad "Puntas blancas", zucchini: Cucurbita maxima variedad "Veronés", rúcula: Eruca sativa y achicoria: Cichorium intybus) en presencia de extractos acuosos de los residuos avícolas. Las comunidades bacterianas presentes en los residuos estuvieron dominadas por miembros típicos del tracto gastrointestinal de las aves, destacando la presencia de familias de bacterias patógenas (Xanthomonadaceae, Clostridiales, Staphylococcaceae, Flavobacteriaceae, Sphingobacteriaceae). Los suelos sometidos a aplicaciones de guano de ponedoras mostraron valores estadísticamente más altos de fósforo total y fósforo extraíble respecto del suelo control, aumentando el riesgo de eutrofización. Por su parte, las comunidades bacterianas de los suelos sometidos a aplicaciones prolongadas de residuos avícolas permanecieron dominadas por familias de bacterias involucradas en los ciclos biogeoquímicos de los nutrientes y en la promoción del crecimiento de las plantas (Gemmatimonadaceae, Sphingomonadaceae, Nitrosomonadaceae, Planctomycetaceae, Nitrospiraceae), destacando la capacidad de resiliencia del suelo. Sin embargo, no debe descartarse la persistencia de bacterias de importancia sanitaria. En conjunto, nuestro trabajo contribuye a comprender los efectos de las prácticas agrícolas locales y, por lo tanto, al apoyo de la adopción de procesos de biotransformación previos a la reutilización de los residuos, de acuerdo con las pautas de sostenibilidad ambiental.Instituto de Microbiología y Zoología Agrícola (IMYZA)Fil: Pin Viso, Natalia Daniela. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Agrobiotecnología y Biología Molecular; ArgentinaFil: Pin Viso, Natalia Daniela. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Pin Viso, Natalia Daniela. Universidad Nacional de Hurlingham; ArgentinaFil: Rizzo, Pedro Federico. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Microbiología y Zoología Agrícola; ArgentinaFil: Young, Brian Jonathan. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Microbiología y Zoología Agrícola; ArgentinaFil: Gabioud, Emmanuel Adrian. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Paraná; ArgentinaFil: Bres, Patricia Alina. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Microbiología y Zoología Agrícola; ArgentinaFil: Riera, Nicolas Iván. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Microbiología y Zoología Agrícola; ArgentinaFil: Merino, Lina. Universidad Nacional de Hurlingham; ArgentinaFil: Farber, Marisa Diana. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Agrobiotecnologia y Biologia Molecular; ArgentinaFil: Farber, Marisa Diana. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Farber, Marisa Diana. Universidad Nacional de Hurlingham; Argentin

DeepSearch: A Simple and Effective Blackbox Attack for Deep Neural Networks

Although deep neural networks have been very successful in image-classification tasks, they are prone to adversarial attacks. To generate adversarial inputs, there has emerged a wide variety of techniques, such as black- and whitebox attacks for neural networks. In this paper, we present DeepSearch, a novel fuzzing-based, query-efficient, blackbox attack for image classifiers. Despite its simplicity, DeepSearch is shown to be more effective in finding adversarial inputs than state-of-the-art blackbox approaches. DeepSearch is additionally able to generate the most subtle adversarial inputs in comparison to these approaches

Structural and functional analyses of the DMC1-M200V polymorphism found in the human population

The M200V polymorphism of the human DMC1 protein, which is an essential, meiosis-specific DNA recombinase, was found in an infertile patient, raising the question of whether this homozygous human DMC1-M200V polymorphism may cause infertility by affecting the function of the human DMC1 protein. In the present study, we determined the crystal structure of the human DMC1-M200V variant in the octameric-ring form. Biochemical analyses revealed that the human DMC1-M200V variant had reduced stability, and was moderately defective in catalyzing in vitro recombination reactions. The corresponding M194V mutation introduced in the Schizosaccharomyces pombe dmc1 gene caused a significant decrease in the meiotic homologous recombination frequency. Together, these structural, biochemical and genetic results provide extensive evidence that the human DMC1-M200V mutation impairs its function, supporting the previous interpretation that this single-nucleotide polymorphism is a source of human infertility

CMS distributed computing workflow experience

The vast majority of the CMS Computing capacity, which is organized in a tiered hierarchy, is located away from CERN. The 7 Tier-1 sites archive the LHC proton-proton collision data that is initially processed at CERN. These sites provide access to all recorded and simulated data for the Tier-2 sites, via wide-area network (WAN) transfers. All central data processing workflows are executed at the Tier-1 level, which contain re-reconstruction and skimming workflows of collision data as well as reprocessing of simulated data to adapt to changing detector conditions. This paper describes the operation of the CMS processing infrastructure at the Tier-1 level. The Tier-1 workflows are described in detail. The operational optimization of resource usage is described. In particular, the variation of different workflows during the data taking period of 2010, their efficiencies and latencies as well as their impact on the delivery of physics results is discussed and lessons are drawn from this experience. The simulation of proton-proton collisions for the CMS experiment is primarily carried out at the second tier of the CMS computing infrastructure. Half of the Tier-2 sites of CMS are reserved for central Monte Carlo (MC) production while the other half is available for user analysis. This paper summarizes the large throughput of the MC production operation during the data taking period of 2010 and discusses the latencies and efficiencies of the various types of MC production workflows. We present the operational procedures to optimize the usage of available resources and we the operational model of CMS for including opportunistic resources, such as the larger Tier-3 sites, into the central production operation

Search for the standard model Higgs boson in the H to ZZ to 2l 2nu channel in pp collisions at sqrt(s) = 7 TeV

A search for the standard model Higgs boson in the H to ZZ to 2l 2nu decay channel, where l = e or mu, in pp collisions at a center-of-mass energy of 7 TeV is presented. The data were collected at the LHC, with the CMS detector, and correspond to an integrated luminosity of 4.6 inverse femtobarns. No significant excess is observed above the background expectation, and upper limits are set on the Higgs boson production cross section. The presence of the standard model Higgs boson with a mass in the 270-440 GeV range is excluded at 95% confidence level.Comment: Submitted to JHE

Combined search for the quarks of a sequential fourth generation

Results are presented from a search for a fourth generation of quarks produced singly or in pairs in a data set corresponding to an integrated luminosity of 5 inverse femtobarns recorded by the CMS experiment at the LHC in 2011. A novel strategy has been developed for a combined search for quarks of the up and down type in decay channels with at least one isolated muon or electron. Limits on the mass of the fourth-generation quarks and the relevant Cabibbo-Kobayashi-Maskawa matrix elements are derived in the context of a simple extension of the standard model with a sequential fourth generation of fermions. The existence of mass-degenerate fourth-generation quarks with masses below 685 GeV is excluded at 95% confidence level for minimal off-diagonal mixing between the third- and the fourth-generation quarks. With a mass difference of 25 GeV between the quark masses, the obtained limit on the masses of the fourth-generation quarks shifts by about +/- 20 GeV. These results significantly reduce the allowed parameter space for a fourth generation of fermions.Comment: Replaced with published version. Added journal reference and DO

Measurement of the Z/gamma* + b-jet cross section in pp collisions at 7 TeV

The production of b jets in association with a Z/gamma* boson is studied using proton-proton collisions delivered by the LHC at a centre-of-mass energy of 7 TeV and recorded by the CMS detector. The inclusive cross section for Z/gamma* + b-jet production is measured in a sample corresponding to an integrated luminosity of 2.2 inverse femtobarns. The Z/gamma* + b-jet cross section with Z/gamma* to ll (where ll = ee or mu mu) for events with the invariant mass 60 < M(ll) < 120 GeV, at least one b jet at the hadron level with pT > 25 GeV and abs(eta) < 2.1, and a separation between the leptons and the jets of Delta R > 0.5 is found to be 5.84 +/- 0.08 (stat.) +/- 0.72 (syst.) +(0.25)/-(0.55) (theory) pb. The kinematic properties of the events are also studied and found to be in agreement with the predictions made by the MadGraph event generator with the parton shower and the hadronisation performed by PYTHIA.Comment: Submitted to the Journal of High Energy Physic

Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV

Results are presented from a search for a W' boson using a dataset corresponding to 5.0 inverse femtobarns of integrated luminosity collected during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV. The W' boson is modeled as a heavy W boson, but different scenarios for the couplings to fermions are considered, involving both left-handed and right-handed chiral projections of the fermions, as well as an arbitrary mixture of the two. The search is performed in the decay channel W' to t b, leading to a final state signature with a single lepton (e, mu), missing transverse energy, and jets, at least one of which is tagged as a b-jet. A W' boson that couples to fermions with the same coupling constant as the W, but to the right-handed rather than left-handed chiral projections, is excluded for masses below 1.85 TeV at the 95% confidence level. For the first time using LHC data, constraints on the W' gauge coupling for a set of left- and right-handed coupling combinations have been placed. These results represent a significant improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe