Herschel views on ultra-luminous X-ray sources

The nature of ultra-luminous X-ray sources (ULXs), which are off-nuclear extragalactic X-ray sources that exceed the Eddington luminosity for a stellar-mass black hole, is still largely unknown. They might be black hole X-ray binaries in a super-Eddington accretion state, possibly with significant beaming of their emission, or they might harbor a black hole of intermediate mass (10^2 to 10^5 solar masses). Due to the enormous amount of energy radiated, ULXs can have strong interactions with their environment, particularly if the emission is not beamed and if they host a massive black hole. We present early results of a project that uses archival Herschel infrared observations of galaxies hosting bright ULXs in order to constrain the nature of the environment surrounding the ULXs and possible interactions. We already observe a spatial correlation between ULXs and dense clouds of cold material, that will be quantified in subsequent work. Those observations will allow us to test the similarities with the environment of Galactic high mass X-ray binaries. This project will also shed light on the nature of the host galaxies, and the possible factors that could favor the presence of a ULX in a galaxy.Comment: Accepted for publication in Proceedings of Science (INTEGRAL 2012), Eds. A. Goldwurm, F. Lebrun and C. Winkler, based on a presentation at the 9th INTEGRAL Workshop, October 15-19, 2012, Paris, Franc

Herschel observations of INTEGRAL supergiant High Mass X-ray Binaries

We present preliminary results on Herschel/PACS mid/far-infrared photometric observations of INTEGRAL supergiant High Mass X-ray Binaries (HMXBs), with the aim of detecting the presence and characterizing the nature of absorbing material (dust and/or cold gas), either enshrouding the whole binary systems, or surrounding the sources within their close environment. These unique observations allow us to better characterize the nature of these HMXBs, to constrain the link with their environment (impact and feedback), and finally to get a better understanding of the formation and evolution of such rare and short-living supergiant HMXBs in our Galaxy.Comment: Proceedings of the 9th INTEGRAL Workshop and celebration of the 10th anniversary of the launch "An INTEGRAL view of the high-energy sky (the first 10 years)", accepted for publication in Proceedings of Science (editors: F. Lebrun, A. Goldwurm and C. Winkler), 4 pages, 2 figure

Herschel observations of dust around the high-mass X-ray binary GX 301-2

We aim at characterising the structure of the gas and dust around the high mass X-ray binary GX 301-2, a highly obscured X-ray binary hosting a hypergiant star and a neutron star, in order to better constrain its evolution. We used Herschel PACS to observe GX 301-2 in the far infrared and completed the spectral energy distribution of the source using published data or catalogs, from the optical to the radio range (0.4 to 4x10^4 micrometer). GX 301-2 is detected for the first time at 70 and 100 micrometer. We fitted different models of circumstellar environments to the data. All tested models are statistically acceptable, and consistent with a hypergiant star at ~3 kpc. We found that the addition of a free-free emission component from the strong stellar wind is required and could dominate the far infrared flux. Through comparisons with similar systems and discussion on the estimated model parameters, we favour a disk-like circumstellar environment of ~8 AU that would enshroud the binary system. The temperature goes down to ~200 K at the edge of the disk, allowing for dust formation. This disk is probably a rimmed viscous disk with an inner rim at the temperature of the dust sublimation temperature (~1500 K). The similarities between the hypergiant GX 301-2, B[e] supergiants and the highly obscured X-ray binaries (in particular IGR J16318-4848) are strengthened. GX 301-2 might represent a transition stage in the evolution of massive stars in binary systems, connecting supergiant B[e] systems to luminous blue variables.Comment: accepted for publication in ApJ (tentatively scheduled for the December 1, 2014, V796 - 2 issue), 15 pages with emulateapj styl

Stepwise drying of Lake Turkana at the end of the African Humid Period: a forced regression modulated by solar activity variations?

Although the timing of the termination of the African Humid Period (AHP) is now relatively well estab- lished, the modes and controlling factors of this drying are still debated. Here, through a geomorphological approach, we characterize the regression of Lake Turkana at the end of the AHP. We show that lake level fall during this period was not continuous but rather stepwise and consisted of five episodes of rapid lake level fall separated by episodes marked by slower rates of lake level fall. Whereas the overall regres- sive trend reflects a decrease in regional precipitations linked to the gradual reduction in Northern Hemisphere summer in- solation, itself controlled by orbital precession, we focus dis- cussion on the origin of the five periods of accelerated lake level fall. We propose that these periods are due to temporary reductions in rainfall across the Lake Turkana area associ- ated with repeated westward displacement of the Congo Air Boundary (CAB) during solar activity minima

L’exercice comme approche alternative dans la gestion des algies vasculaires de la face: étude de cas

Introduction : Plusieurs traitements pharmacologi- ques sont utilisés pour soulager la douleur et réduire la durée et la fréquence des crises d’algie vasculaire de la face (CH), mais ces traitements demeurent partiellement efficaces pour plusieurs patients. L’exercice aérobie est actuellement pro- posé pour réduire la prévalence et la gravité des symptômes associés à d’autres types de céphalées, mais son efficacité concernant la gestion des CH n’a pas encore été documentée. Représentation du cas : Cet article décrit le cas d’un homme de 24 ans chez qui on a diagnostiqué des CH épisodiques (1/jour ; > 1 heure). Treize jours après le premier épisode, des exercices aérobies d’intensité modérée étaient effectués (10 à 30 minutes) au début des crises. L’exercice aérobie a réduit à la fois la sévérité et la durée des crises de CH. Conclusion : Cette étude de cas suggère que la réalisation d’exercices aérobies d’intensité modérée au début d’une crise de CH pourrait être une intervention non pharmacolo- gique complémentaire intéressante pour diminuer les symp- tômes douloureux liés à cette condition.Abstract : Background: Various pharmacological treatments have been used to relieve pain and reduce the duration and occurrence of cluster headache (CH) attacks, but these treatments remain partially effective for many patients. Aerobic exercises have been proposed to decrease the prevalence and severity of symptoms associated with other types of headaches, but the effectiveness of aerobic exercise for CH management has not yet been investigated. Case presentation: This report describes the case of a 24 year-old male patient diagnosed with episodic CH (1/day; > 1h). Thirteen days after the first episode, moderate-intensity continuous aerobic exercise was performed (10-30 minutes) at the onset of CH attack. Aerobic exercise reduced both severity and duration of CH attacks. Conclusions: This case report suggests that performing moderate-intensity aerobic exercise at the onset of a CH attack may be an interesting non-pharmacologic intervention that can be used to ease pain symptoms

Structure-Preserving Transformers for Sequences of SPD Matrices

In recent years, Transformer-based auto-attention mechanisms have been successfully applied to the analysis of a variety of context-reliant data types, from texts to images and beyond, including data from non-Euclidean geometries. In this paper, we present such a mechanism, designed to classify sequences of Symmetric Positive Definite matrices while preserving their Riemannian geometry throughout the analysis. We apply our method to automatic sleep staging on timeseries of EEG-derived covariance matrices from a standard dataset, obtaining high levels of stage-wise performance.Comment: Submitted to the ICASSP 2024 Conference. v2: error correction relative to v1 - Section 1, changed "less anisotropic" to "less isotropic". v3: updated citation 15 (has since been published

Preparation and medical follow-up for a single-handed transatlantic rowing race

Background: A single-handed transatlantic rowing race was organised between Senegal and French Guyana (2600 nautical miles). During the race, rowers adjust their lifestyle to maintain an optimal level of performance. Nutrition, circadian rhythm disturbance, psychological state, pain and other medical problems impact on physical abilities and increase the occurrence of accidents. We surveyed the prevalence of medical complications during this race and the preparation that we could suggest for this kind of activity. Materials and methods: This is a descriptive, retrospective case series study. Follow-up consisted of sending out a questionnaire and performing individual interviews. Results: A total of 23 participants including 1 woman and 22 men; mean age of 46.5 years (range: 35–59) entered the race. The race lasted for 39 to 52 days with participants rowing between 10 and 12 h/day. Nine participants dropped out. Energy intake was 4500 to 6000 kcal/day and fluid intake was 4 to 5.5 L/day. Mean weight loss was 13.3 kg. The resting period was 6 ± 1 h/24 h divided into 1.5 to 2 h periods essentially during darkness. A total of 92% of the racers required medical care for dermatological problems; other conditions requiring medical care were: tendinitis in 10 cases, diarrhoea in 4, moderate to severe seasickness in 4, hallucinations in 3, panic attacks in 2, burns in 2, and disembarkation syndrome (“land sickness”) lasting from 45 min to 6 h in 13. Conclusions: Physiological and psychological impact of this type of event is still unclear. The most common medical problems are dermatological, rheumatological complications and minor trauma. Medical and psychological preparation should be offered to candidates for these competitions.

StateSec: Stateful Monitoring for DDoS Protection in Software Defined Networks

To be presented at IEEE NetSoft, 3-7 July 2017, Bologna, ItalyInternational audienceSoftware-Defined Networking (SDN) allows for fast reactions to security threats by dynamically enforcing simple forwarding rules as countermeasures. However, in classic SDN all the intelligence resides at the controller, with the switches only capable of performing stateless forwarding as ruled by the controller. It follows that the controller, in addition to network management and control duties, must collect and process any piece of information required to take advanced (stateful) forwarding decisions. This threatens both to overload the controller and to congest the control channel. On the other hand, stateful SDN represents a new concept, developed both to improve reactivity and to offload the controller and the control channel by delegating local treatments to the switches. In this paper, we adopt this stateful paradigm to protect end-hosts from Distributed Denial of Service (DDoS). We propose StateSec, a novel approach based on in-switch processing capabilities to detect and mitigate DDoS attacks. StateSec monitors packets matching configurable traffic features (e.g., IP src/dst, port src/dst) without resorting to the controller. By feeding an entropy-based algorithm with such monitoring features, StateSec detects and mitigates several threats such as (D)DoS and port scans with high accuracy. We implemented StateSec and compared it with a state-of-the-art approach to monitor traffic in SDN. We show that StateSec is more efficient: it achieves very accurate detection levels, limiting at the same time the control plane overhead

Robust Domain Adaptation for Pre-trained Multilingual Neural Machine Translation Models

Recent literature has demonstrated the potential of multilingual Neural Machine Translation (mNMT) models. However, the most efficient models are not well suited to specialized industries. In these cases, internal data is scarce and expensive to find in all language pairs. Therefore, fine-tuning a mNMT model on a specialized domain is hard. In this context, we decided to focus on a new task: Domain Adaptation of a pre-trained mNMT model on a single pair of language while trying to maintain model quality on generic domain data for all language pairs. The risk of loss on generic domain and on other pairs is high. This task is key for mNMT model adoption in the industry and is at the border of many others. We propose a fine-tuning procedure for the generic mNMT that combines embeddings freezing and adversarial loss. Our experiments demonstrated that the procedure improves performances on specialized data with a minimal loss in initial performances on generic domain for all languages pairs, compared to a naive standard approach (+10.0 BLEU score on specialized data, -0.01 to -0.5 BLEU on WMT and Tatoeba datasets on the other pairs with M2M100).Comment: Accepted by EMNLP 2022 MMNLU Worksho