Existence test of moments: Application to Multifractal Analysis

The scope of this paper is to present a wavelet-based technique aimed at determining the range of existence for the moments of arbitrary random variables. Our work relies on the characterization of the local Hölder regularity of the characteristic function, as an indicator of the interval bounds under interest. Our motivation stems from multifractal analysis of processes.

Les enjeux relatifs à l’implantation de bracelets antirapprochements (BAR) en contexte de violence conjugale au Québec

Actuellement, la violence conjugale demeure un phénomène social grave et complexe au sein de nos sociétés contemporaines. Au Canada, le taux de violence perpétrée par un partenaire intime ne cesse d’augmenter depuis plusieurs années et la récente pandémie de COVID-19 survenue en 2020 a aggravé les épisodes de tension au sein des foyers, notamment en raison des mesures sanitaires restrictives. Plus que jamais, la protection des victimes de violence conjugale devient critique, et c’est pourquoi il est essentiel que toutes les mesures de prévention disponibles doivent être mises en œuvre dans ce but commun. Ce mémoire propose donc d’explorer les enjeux relatifs à l’implantation de bracelets antirapprochements (BAR) comme moyen de prévention des homicides conjugaux au Québec. Sur la base d’entretiens semi-directifs, l’échantillon est composé d’un total de 14 participants, dont 6 proviennent d’organismes policiers, 3 proviennent d’organismes impliqués dans la gestion des personnes contrevenantes, 3 sont issus d’organismes impliqués dans les missions d’aide aux victimes et 2 sont issus d’organismes associés à la défense des droits de la personne. L’analyse des données recueillies met en évidence quatre types d’enjeux relatifs à l’implantation de BAR en contexte de violence conjugale au Québec, à savoir les enjeux technologiques, légaux, éthiques et sociaux. Ces derniers devront faire l’objet d’une analyse approfondie par les décideurs advenant l’implantation du BAR au Québec. Cela étant, le BAR s’inscrit comme un outil de prévention tertiaire innovant et prometteur des homicides conjugaux, et relève d’un grand potentiel quant à l’amélioration de la qualité de vie des victimes.Currently, intimate partner violence remains a serious and complex social phenomenon within our contemporary societies. In Canada, the rate of violence perpetrated by an intimate partner has been steadily increasing for several years and the recent pandemic of COVID-19 which occurred in 2020 has aggravated episodes of tension within homes, due to restrictive health measures among others. More than ever, the protection of victims of intimate partner violence becomes critical, and that is why it is essential that all available prevention measures must be implemented for this common purpose. This thesis therefore proposes to explore the issues relating to the implantation of anti-reconciliation bracelets (BAR) as a means of preventing spousal homicides in Quebec. Based on semi-structured interviews, the sample is made up of a total of 14 participants, including 6 from police organizations, 3 from organizations involved in the management of offenders, 3 from organizations involved in victim assistance missions and 2 are from organizations associated with the defense of human rights. The analysis of the data collected highlights four types of issues relating to the implementation of BAR in the context of intimate partner violence in Quebec, namely technological, legal, ethical and social issues. These will have to be the subject of an in-depth analysis by the decision-makers in the event of the establishment of the BAR in Quebec. That said, the BAR is an innovative and promising tertiary prevention tool for spousal homicides and has great potential for improving the quality of life of victims

Hydroxyapatite coating on titanium by a low energy plasma spraying mini-gun

Plasma-sprayed hydroxyapatite (HA) coatings are used on metallic implants to improve osseointegration and bone growth. The purpose of this work was to determine the microstructure and composition of HA coatings obtained with a newly developed low energy plasma spray mini-gun employing an HA feedstock powder with smaller granulometry than that commonly used. The microstructure and the phase composition of the coatings obtained by varying the number of mini-gun runs were examined using scanning electron microscopy, X-ray diffraction and Fourier transform infrared and micro-Raman spectroscopy. In all cases, the results indicate the presence of an amorphous phase and oxyapatite in the coatings due to hydroxyl group removal. No other foreign crystalline phases were detected. The absence of foreign phases was attributed to the fast cooling rate of the small particles used in the experiments and the low amount of energy employed with the mini-gun. Decomposition in the υ1PO4 region of the Raman spectra allowed a semi-quantitative evaluation of the phase contents as a function of the number of runs. Micro-Raman spectroscopy appears to be a powerful technique providing comprehensive and localised information concerning calcium phosphate phases in coatings

Influence of intensive agriculture and geological heterogeneity on the recharge of an arid aquifer system (Saq–Ram, Arabian Peninsula) inferred from GRACE data

This study assesses the detailed water budget of the Saq–Ram Aquifer System (520 000 km2) over the 2002–2019 period using satellite gravity data from the Gravity Recovery And Climate Experiment (GRACE). The three existing GRACE solutions were tested for their local compatibility to compute groundwater storage (GWS) variations in combination with the three soil moisture datasets available from the land surface models (LSMs) of the Global Land Data Assimilation System (GLDAS). Accounting for groundwater pumping, artificial recharge, and natural discharge uniformly distributed over the Saq–Ram domain, the GRACE-derived mass balance calculation for water yields a long-term estimate of the domain-averaged natural recharge of (2.4±1.4) mm yr−1, corresponding to (4.4±2.6) % of the annual average rainfall (AAR). Beyond the regional-scale approach proposed here, spatial heterogeneities regarding the groundwater recharge were identified. The first source of heterogeneity is of anthropogenic origin: chiefly induced by irrigation excess over irrigated surfaces (about 1 % of the domain), artificial recharge corresponds to half of the total recharge of the aquifer. The second source of recharge heterogeneity identified here is natural: volcanic lava deposits (called harrats on the Arabian Peninsula) which cover 8 % of the Saq–Ram aquifer domain but contribute to more than 50 % of the natural recharge. Hence, in addition to this application on the Arabian Peninsula, this study strongly indicates a major control of geological context on arid aquifer recharge, which has been poorly discussed hitherto. Due to large lag times of the diffuse recharge mechanism, the annual analysis using this GRACE–GLDAS approach in arid domains should be limited to areas where focused recharge is the main mechanism, while long-term analysis is valid regardless of the recharge mechanism. Moreover, it appears that about 15 years of GRACE records are required to obtain a relevant long-term recharge estimate.</p

Regional coherence evaluation in mild cognitive impairment and Alzheimer's disease based on adaptively extracted magnetoencephalogram rhythms

This study assesses the connectivity alterations caused by Alzheimer's disease (AD) and mild cognitive impairment (MCI) in magnetoencephalogram (MEG) background activity. Moreover, a novel methodology to adaptively extract brain rhythms from the MEG is introduced. This methodology relies on the ability of empirical mode decomposition to isolate local signal oscillations and constrained blind source separation to extract the activity that jointly represents a subset of channels. Inter-regional MEG connectivity was analysed for 36 AD, 18 MCI and 26 control subjects in δ, θ, α and β bands over left and right central, anterior, lateral and posterior regions with magnitude squared coherence—c(f). For the sake of comparison, c(f) was calculated from the original MEG channels and from the adaptively extracted rhythms. The results indicated that AD and MCI cause slight alterations in the MEG connectivity. Computed from the extracted rhythms, c(f) distinguished AD and MCI subjects from controls with 69.4% and 77.3% accuracies, respectively, in a full leave-one-out cross-validation evaluation. These values were higher than those obtained without the proposed extraction methodology

Time-frequency detection of Gravitational Waves

We present a time-frequency method to detect gravitational wave signals in interferometric data. This robust method can detect signals from poorly modeled and unmodeled sources. We evaluate the method on simulated data containing noise and signal components. The noise component approximates initial LIGO interferometer noise. The signal components have the time and frequency characteristics postulated by Flanagan and Hughes for binary black hole coalescence. The signals correspond to binaries with total masses between $45 M_\odot$ to $70 M_\odot$ and with (optimal filter) signal-to-noise ratios of 7 to 12. The method is implementable in real time, and achieves a coincident false alarm rate for two detectors $\approx$ 1 per 475 years. At this false alarm rate, the single detector false dismissal rate for our signal model is as low as 5.3% at an SNR of 10. We expect to obtain similar or better detection rates with this method for any signal of similar power that satisfies certain adiabaticity criteria. Because optimal filtering requires knowledge of the signal waveform to high precision, we argue that this method is likely to detect signals that are undetectable by optimal filtering, which is at present the best developed detection method for transient sources of gravitational waves.Comment: 24 pages, 5 figures, uses REVTE