Le graffiti à Montréal : pratique machiste et stratégies féminines

Le graffiti est depuis longtemps associé au vandalisme dans les métropoles où il prolifère. Il s’intègre au paysage urbain à un point tel que, même s’il procède d’une logique de visibilité et de promotion, nous parvenons à ne plus le remarquer. Pourtant, sa présence suscite toujours la colère des citoyens propriétaires de murs vandalisés et des autorités municipales qui, chaque année, dépensent de grosses sommes d’argent pour l’effacer. Malgré les restrictions et les amendes, le graffiti est néanmoins devenu un véritable phénomène d’art urbain : des artistes graffiteurs ont atteint la notoriété en dehors de leur sous-culture et ont pu exposer légalement leur travail, du fait d’un intérêt croissant du milieu officiel de l’art. Celui-ci contribue à faire grandir l’engouement et l’enthousiasme pour une pratique d’art urbaine. Le graffiti illustre l’expression d’une identité qui s’approprie et subvertit les surfaces urbaines de la ville, au moyen d’un nom propre fictif qui n’a aucune légitimation juridique et légale. De plus, l’application et la diffusion de la signature graffitique communiquent des valeurs qui guident et définissent toute la sous-culture du graffiti. Ces valeurs sont culturellement considérées comme masculines : le risque, le défi et la dissidence. La figure de l’artiste graffiteur apparaît ainsi comme une figure marginale et rebelle. Un tel portrait laisse alors entrevoir une culture fortement machiste, d’autant plus que les garçons qui exercent le graffiti sont beaucoup plus nombreux. Or, si les femmes artistes de la communauté graffitique représentent une minorité, c’est notamment parce que leur attrait pour une pratique illicite, nocturne et dangereuse est moindre. À partir d’une approche qui touche aux gender studies et à certains concepts traditionnels de l’histoire de l’art, nous cherchons à expliquer l’intérêt généralement plus faible des femmes pour le graffiti. Nous désirons également démontrer comment l’exercice des artistes féminines du graffiti se distingue de celui de leurs homologues masculins. De quelle manière se détermine leur expérience? Leur iconographie sert-elle à les définir? Quelles sont leurs opinions et leurs perceptions sur leur propre culture? Finalement, comment caractérisent-elles leur statut de femme artiste au sein d’une communauté "machiste"?

Analysis Of The Dna Fourier Transform-infrared Microspectroscopic Signature Using An All-reflecting Objective.

The Fourier transform-infrared (FT-IR) signature of dry samples of DNA and DNA-polypeptide complexes, as studied by IR microspectroscopy using a diamond attenuated total reflection (ATR) objective, has revealed important discriminatory characteristics relative to the PO2(-) vibrational stretchings. However, DNA IR marks that provide information on the sample's richness in hydrogen bonds have not been resolved in the spectral profiles obtained with this objective. Here we investigated the performance of an all reflecting objective (ARO) for analysis of the FT-IR signal of hydrogen bonds in DNA samples differing in base richness types (salmon testis vs calf thymus). The results obtained using the ARO indicate prominent band peaks at the spectral region representative of the vibration of nitrogenous base hydrogen bonds and of NH and NH2 groups. The band areas at this spectral region differ in agreement with the DNA base richness type when using the ARO. A peak assigned to adenine was more evident in the AT-rich salmon DNA using either the ARO or the ATR objective. It is concluded that, for the discrimination of DNA IR hydrogen bond vibrations associated with varying base type proportions, the use of an ARO is recommended.

Gravitational signature of Schwarzschild black holes in dynamical Chern-Simons gravity

Dynamical Chern-Simons gravity is an extension of general relativity in which the gravitational field is coupled to a scalar field through a parity-violating Chern-Simons term. In this framework, we study perturbations of spherically symmetric black hole spacetimes, assuming that the background scalar field vanishes. Our results suggest that these spacetimes are stable, and small perturbations die away as a ringdown. However, in contrast to standard general relativity, the gravitational waveforms are also driven by the scalar field. Thus, the gravitational oscillation modes of black holes carry imprints of the coupling to the scalar field. This is a smoking gun for Chern-Simons theory and could be tested with gravitational-wave detectors, such as LIGO or LISA. For negative values of the coupling constant, ghosts are known to arise, and we explicitly verify their appearance numerically. Our results are validated using both time evolution and frequency domain methods.

Signature of the interaction between dark energy and dark matter in observations

We investigate the effect of an interaction between dark energy and dark matter upon the dynamics of galaxy clusters. This effect is computed through the Layser-Irvine equation, which describes how an astrophysical system reaches virial equilibrium and was modified to include the dark interactions. Using observational data from almost 100 purportedly relaxed galaxy clusters we put constraints on the strength of the couplings in the dark sector. We compare our results with those from other observations and find that a positive (in the sense of energy flow from dark energy to dark matter) nonvanishing interaction is consistent with the data within several standard deviations.

One-time signature scheme from syndrome decoding over generic error-correcting codes

We describe a one-time signature scheme based on the hardness of the syndrome decoding problem, and prove it secure in the random oracle model. Our proposal can be instantiated on general linear error correcting codes, rather than restricted families like alternant codes for which a decoding trapdoor is known to exist. (C) 2010 Elsevier Inc. All rights reserved,

A lipocalin sequence signature modulates cell survival

Lipocalins are beta-barrel proteins, which share three conserved motifs in their amino acid sequence. In this study, we identified by a peptide mapping approach, a seven-amino acid sequence related to one of these motifs (motif 2) that modulates cell survival. A synthetic peptide based on an insect lipocalin displayed cytoprotective activity in serum-deprived endothelial cells and leucocytes. This activity was dependent on nitric oxide synthase. This sequence was found within several lipocalins, including apolipoprotein D, retinol binding protein, lipocalin-type prostaglandin D synthase, and many unknown proteins, suggesting that it is a sequence signature and a lipocalin conserved property. (C) 2010 Federation of European Biochemical Societies. Published by Elsevier B. V. All rights reserved.

The Reflectance Signature of Canopy Components: Implications for the Interpretation of Remotely Sensed Images

The reflectance signatures of plantation pine canopy and understorey components were measured using a spectro-radiometer. The aim was to establish whether differences observed in the reflectance signature of stressed and unstressed pine needles were consistent with observed differences in the reflectance of multispectral Landsat Thematic Mapper (TM) images of healthy and stressed forest. Because overall scene reflectance includes the contribution of each scene component, needle reflectance may not be representative of canopy reflectance. In this investigation, a limited dataset of reflectance signatures from stressed and unstressed needles confirmed the negative relationship between pine needle health and reflectance which was observed in visible red wavelengths. However, the reflectance contribution from bushes, pine needle litter and bare soil tended to reinforce this relationship suggesting that in this instance, overall scene reflectance is comprised of the proportional reflectance of each scene component. In near infrared wavelengths, differences between healthy and stressed needle reflectance suggested a strong positive relationship between reflectance and tree health. For Landsat TM images, previous research had only observed a weak positive relationship between stand health and near infrared reflectance in these pine canopies. This suggests that for multispectral Landsat TM images, reflectance of near infrared light from pine canopies may be affected by other factors which may include the scattering of light within canopies. These results are seen as promising for the use of hyperspectral images to detect stand health, provided that pixel reflectance is not influenced by other scene components.

Signature of mott-insulator transition with ultracold fermions in a one-dimensional optical lattice

Using the exact Bethe ansatz solution of the Hubbard model and Luttinger liquid theory, we investigate the density profiles and collective modes of one-dimensional ultracold fermions confined in an optical lattice with a harmonic trapping potential. We determine a generic phase diagram in terms of a characteristic filling factor and a dimensionless coupling constant. The collective oscillations of the atomic mass density, a technique that is commonly used in experiments, provide a signature of the quantum phase transition from the metallic phase to the Mott-insulator phase. A detailed experimental implementation is proposed.

Acoustic signature of the normal swallow: Characterization by age, gender, and bolus volume

Despite growing clinical use, cervical auscultation suffers from a lack of research-based data. One of the strongest criticisms of cervical auscultation is that there has been little research to demonstrate how dysphagic swallowing sounds are different from normal swallowing sounds, In order to answer this question, however, one first needs to document the acoustic characteristics of normal, nondysphagic swallowing sounds, This article provides the first normative database of normal swallowing sounds for the adult population. The current investigation documents the acoustic characteristics of normal swallowing sounds for individuals from 18 to more than 60 years of age over a range of thin liquid volumes. Previous research has shown the normal swallow to be a dynamic event. The normal swallow is sensitive to aging of the oropharyngeal system, and also to the volume of bolus swallowed. The current investigation found that the acoustic signals generated during swallowing were sensitive to an individual's age and to the volume of the bolus swallowed. There were also some gender-specific differences in the acoustic profile of the swallowing sound, It is anticipated that the results will provide a catalyst for further research into cervical auscultation.

INFLUENCE OF MANUFACTURER SIGNATURE ON STORE BRANDS' LOYALTY AND PURCHASE INTENTION

ABSTRACT With today's trend toward higher store concentration, building strong store brands has become a priority for many retailing companies. This study aims to analyze the differences in store brands' purchasing likelihood between store brands with a manufacturer identification - a manufacturer signature - and store brands with no information about the manufacturer, as well as the moderating role of the manufacturer signature on store brands' purchase intention. We carried out multiple group analysis through structural equation modeling. Our findings suggest that store brand image has the most significant influence on loyalty and purchase intention for both types of store brands. Moreover, and contrary to our expectations, we did not find empirical support for the moderating role of manufacturer signature on store brands' purchasing likelihood.

XAdES4J: a java library for XAdES signature services

As comunicações electrónicas são cada vez mais o meio de eleição para negócios entre entidades e para as relações entre os cidadãos e o Estado (e-government). Esta diversidade de transacções envolve, muitas vezes, informação sensível e com possível valor legal. Neste contexto, as assinaturas electrónicas são uma importante base de confiança, fornecendo garantias de integridade e autenticação entre os intervenientes. A produção de uma assinatura digital resulta não só no valor da assinatura propriamente dita, mas também num conjunto de informação adicional acerca da mesma, como o algoritmo de assinatura, o certificado de validação ou a hora e local de produção. Num cenário heterogéneo como o descrito anteriormente, torna-se necessária uma forma flexível e interoperável de descrever esse tipo de informação. A linguagem XML é uma forma adequada de representar uma assinatura neste contexto, não só pela sua natureza estruturada, mas principalmente por ser baseada em texto e ter suporte generalizado. A recomendação XML Signature Syntax and Processing (ou apenas XML Signature) foi o primeiro passo na representação de assinaturas em XML. Nela são definidas sintaxe e regras de processamento para criar, representar e validar assinaturas digitais. As assinaturas XML podem ser aplicadas a qualquer tipo de conteúdos digitais identificáveis por um URI, tanto no mesmo documento XML que a assinatura, como noutra qualquer localização. Além disso, a mesma assinatura XML pode englobar vários recursos, mesmo de tipos diferentes (texto livre, imagens, XML, etc.). À medida que as assinaturas electrónicas foram ganhando relevância tornou-se evidente que a especificação XML Signature não era suficiente, nomeadamente por não dar garantias de validade a longo prazo nem de não repudiação. Esta situação foi agravada pelo facto da especificação não cumprir os requisitos da directiva 1999/93/EC da União Europeia, onde é estabelecido um quadro legal para as assinaturas electrónicas a nível comunitário. No seguimento desta directiva da União Europeia foi desenvolvida a especificação XML Advanced Electronic Signatures que define formatos XML e regras de processamento para assinaturas electrónicas não repudiáveis e com validade verificável durante períodos de tempo extensos, em conformidade com a directiva. Esta especificação estende a recomendação XML Signature, definindo novos elementos que contêm informação adicional acerca da assinatura e dos recursos assinados (propriedades qualificadoras). A plataforma Java inclui, desde a versão 1.6, uma API de alto nível para serviços de assinaturas digitais em XML, de acordo com a recomendação XML Signature. Contudo, não existe suporte para assinaturas avançadas. Com este projecto pretende-se desenvolver uma biblioteca Java para a criação e validação de assinaturas XAdES, preenchendo assim a lacuna existente na plataforma. A biblioteca desenvolvida disponibiliza uma interface com alto nível de abstracção, não tendo o programador que lidar directamente com a estrutura XML da assinatura nem com os detalhes do conteúdo das propriedades qualificadoras. São definidos tipos que representam os principais conceitos da assinatura, nomeadamente as propriedades qualificadoras e os recursos assinados, sendo os aspectos estruturais resolvidos internamente. Neste trabalho, a informação que compõe uma assinatura XAdES é dividia em dois grupos: o primeiro é formado por características do signatário e da assinatura, tais como a chave e as propriedades qualificadoras da assinatura. O segundo grupo é composto pelos recursos assinados e as correspondentes propriedades qualificadoras. Quando um signatário produz várias assinaturas em determinado contexto, o primeiro grupo de características será semelhante entre elas. Definiu-se o conjunto invariante de características da assinatura e do signatário como perfil de assinatura. O conceito é estendido à verificação de assinaturas englobando, neste caso, a informação a usar nesse processo, como por exemplo os certificados raiz em que o verificador confia. Numa outra perspectiva, um perfil constitui uma configuração do serviço de assinatura correspondente. O desenho e implementação da biblioteca estão também baseados no conceito de fornecedor de serviços. Um fornecedor de serviços é uma entidade que disponibiliza determinada informação ou serviço necessários à produção e verificação de assinaturas, nomeadamente: selecção de chave/certificado de assinatura, validação de certificados, interacção com servidores de time-stamp e geração de XML. Em vez de depender directamente da informação em causa, um perfil — e, consequentemente, a operação correspondente — é configurado com fornecedores de serviços que são invocados quando necessário. Para cada tipo de fornecedor de serviços é definida um interface, podendo as correspondentes implementações ser configuradas de forma independente. A biblioteca inclui implementações de todos os fornecedores de serviços, sendo algumas delas usadas for omissão na produção e verificação de assinaturas. Uma vez que o foco do projecto é a especificação XAdES, o processamento e estrutura relativos ao formato básico são delegados internamente na biblioteca Apache XML Security, que disponibiliza uma implementação da recomendação XML Signature. Para validar o funcionamento da biblioteca, nomeadamente em termos de interoperabilidade, procede-se, entre outros, à verificação de um conjunto de assinaturas produzidas por Estados Membros da União Europeia, bem como por outra implementação da especificação XAdES.

A novel gene expression signature in peripheral blood mononuclear cells for early detection of colorectal cancer.

BACKGROUND: Early detection and treatment of colorectal adenomatous polyps (AP) and colorectal cancer (CRC) is associated with decreased mortality for CRC. However, accurate, non-invasive and compliant tests to screen for AP and early stages of CRC are not yet available. A blood-based screening test is highly attractive due to limited invasiveness and high acceptance rate among patients. AIM: To demonstrate whether gene expression signatures in the peripheral blood mononuclear cells (PBMC) were able to detect the presence of AP and early stages CRC. METHODS: A total of 85 PBMC samples derived from colonoscopy-verified subjects without lesion (controls) (n = 41), with AP (n = 21) or with CRC (n = 23) were used as training sets. A 42-gene panel for CRC and AP discrimination, including genes identified by Digital Gene Expression-tag profiling of PBMC, and genes previously characterised and reported in the literature, was validated on the training set by qPCR. Logistic regression analysis followed by bootstrap validation determined CRC- and AP-specific classifiers, which discriminate patients with CRC and AP from controls. RESULTS: The CRC and AP classifiers were able to detect CRC with a sensitivity of 78% and AP with a sensitivity of 46% respectively. Both classifiers had a specificity of 92% with very low false-positive detection when applied on subjects with inflammatory bowel disease (n = 23) or tumours other than CRC (n = 14). CONCLUSION: This pilot study demonstrates the potential of developing a minimally invasive, accurate test to screen patients at average risk for colorectal cancer, based on gene expression analysis of peripheral blood mononuclear cells obtained from a simple blood sample.

An atlas of human gene expression from massively parallel signature sequencing (MPSS).

We have used massively parallel signature sequencing (MPSS) to sample the transcriptomes of 32 normal human tissues to an unprecedented depth, thus documenting the patterns of expression of almost 20,000 genes with high sensitivity and specificity. The data confirm the widely held belief that differences in gene expression between cell and tissue types are largely determined by transcripts derived from a limited number of tissue-specific genes, rather than by combinations of more promiscuously expressed genes. Expression of a little more than half of all known human genes seems to account for both the common requirements and the specific functions of the tissues sampled. A classification of tissues based on patterns of gene expression largely reproduces classifications based on anatomical and biochemical properties. The unbiased sampling of the human transcriptome achieved by MPSS supports the idea that most human genes have been mapped, if not functionally characterized. This data set should prove useful for the identification of tissue-specific genes, for the study of global changes induced by pathological conditions, and for the definition of a minimal set of genes necessary for basic cell maintenance. The data are available on the Web at http://mpss.licr.org and http://sgb.lynxgen.com.

A robust genomic signature for the detection of colorectal cancer patients with microsatellite instability phenotype and high mutation frequency.

Microsatellite instability (MSI) occurs in 10-20% of colorectal tumours and is associated with good prognosis. Here we describe the development and validation of a genomic signature that identifies colorectal cancer patients with MSI caused by DNA mismatch repair deficiency with high accuracy. Microsatellite status for 276 stage II and III colorectal tumours has been determined. Full-genome expression data was used to identify genes that correlate with MSI status. A subset of these samples (n = 73) had sequencing data for 615 genes available. An MSI gene signature of 64 genes was developed and validated in two independent validation sets: the first consisting of frozen samples from 132 stage II patients; and the second consisting of FFPE samples from the PETACC-3 trial (n = 625). The 64-gene MSI signature identified MSI patients in the first validation set with a sensitivity of 90.3% and an overall accuracy of 84.8%, with an AUC of 0.942 (95% CI, 0.888-0.975). In the second validation, the signature also showed excellent performance, with a sensitivity 94.3% and an overall accuracy of 90.6%, with an AUC of 0.965 (95% CI, 0.943-0.988). Besides correct identification of MSI patients, the gene signature identified a group of MSI-like patients that were MSS by standard assessment but MSI by signature assessment. The MSI-signature could be linked to a deficient MMR phenotype, as both MSI and MSI-like patients showed a high mutation frequency (8.2% and 6.4% of 615 genes assayed, respectively) as compared to patients classified as MSS (1.6% mutation frequency). The MSI signature showed prognostic power in stage II patients (n = 215) with a hazard ratio of 0.252 (p = 0.0145). Patients with an MSI-like phenotype had also an improved survival when compared to MSS patients. The MSI signature was translated to a diagnostic microarray and technically and clinically validated in FFPE and frozen samples.

Including the workload effect in the parallel program signature

Performance prediction and application behavior modeling have been the subject of exten- sive research that aim to estimate applications performance with an acceptable precision. A novel approach to predict the performance of parallel applications is based in the con- cept of Parallel Application Signatures that consists in extract an application most relevant parts (phases) and the number of times they repeat (weights). Executing these phases in a target machine and multiplying its exeuction time by its weight an estimation of the application total execution time can be made. One of the problems is that the performance of an application depends on the program workload. Every type of workload affects differently how an application performs in a given system and so affects the signature execution time. Since the workloads used in most scientific parallel applications have dimensions and data ranges well known and the behavior of these applications are mostly deterministic, a model of how the programs workload affect its performance can be obtained. We create a new methodology to model how a program’s workload affect the parallel application signature. Using regression analysis we are able to generalize each phase time execution and weight function to predict an application performance in a target system for any type of workload within predefined range. We validate our methodology using a synthetic program, benchmarks applications and well known real scientific applications.