Using an Alternative Forced-choice Method to Study Shock Perception at Cyclists’ Hands: The Effect of Tyre Pressure

AbstractIn road cycling, tyre pressure has an influence on both performance and comfort of the cyclist. In this paper, the relationship between tyre pressure and shock perception at the cyclist's hands was quantitatively analysed by measuring the Just Noticeable Difference in Level (JNDL) of tyre pressure. The JNDL was determined by using a three-alternative forced-choice (3-AFC) method. The measurement was carried out on seven healthy subjects exposed to shock-type excitation on a laboratory bicycle treadmill. The dispersion of the measured tyre pressure JNDL (69 to 241 kPa; mean 155 kPa; SD 73 kPa) shows a large variability in the hands’ perception of shock in the cyclists tested. This suggests that some cyclists have a better capacity than others to differentiate impact sensory inputs at the hands, making them more likely to discern subtle differences in bicycle response dynamics

Élaboration d'un modèle de référence pour le système d'encadrement par programme au cégep de Sherbrooke rapport final /

Également disponible en version papier.Titre de l'écran-titre (visionné le 24 mars 2011)Bibliogr

Transport property study of MgO-GaAs(001) contacts for spin injection devices

International audienceThe electrical properties of Au/MgO/n-GaAs(001) tunnel structures have been investigated with capacitance-voltage and current-voltage measurements at room temperature with various MgO thicknesses between 0.5 and 6.0nm. For an oxide thickness higher than 2nm and for low bias voltages, the voltage essentially drops across the oxide and the structure progressively enters the high-current mode of operation with increasing reverse bias voltage, the property sought in spin injection devices. In this mode, we demonstrate that a large amount of charge accumulates at the MgO/GaAsinterface in interface traps located in the semiconductor band gap

Sexuality-Based Stigma and Access to Care: Intersecting Perspectives Between Health Care Providers and Men Who Have Sex With Men in HIV Care Centres in Senegal

Context: Men who have sex with men (MSM) in Senegal face a challenging socio-legal context, marked by homophobia and the illegality of homosexuality. In addition, HIV prevalence among MSM is 27.6%, 46 times greater than the one in the general population (0.5%). Nevertheless, access to health care by MSM may be hampered by stigmatising attitudes from health facility staff (medical and non-medical). // Aims and Methods: This article describes the health facility staff/MSM relationship and analyses its effects on access to healthcare by MSM. The data used was collected through a field survey based on observations and qualitative interviews conducted in 2019 and 2020 with 16 MSM, 1 NGO staff and 9 health care providers in Dakar (the capital city) and Mbour (secondary city on the West Coast) hospitals. The data was subject to a thematic analysis assisted by the ATLAS software. // Results: The relationship between MSM and health care providers is ambiguous. On the one hand, health care providers are torn between their professional duty to treat MSM and the cost of being stigmatised by other colleagues. Therefore, they often limit their empathy with MSM within the hospital context. On the other hand, MSM, trusting in the confidentiality of health care providers, feel safe in the care pathway. However, we identify the following stigmatising factors limiting access to care include: (1) fear of meeting a relative, (2) difficult relationships with non-medical support staff (mainly security guards), (3) HIV status disclosure and (4) potential conflicts with other MSM. // Conclusion: This study is unique as it includes non-medical staff in its respondents. It shows that hospitals are divided into several areas, based on the stigma perceived by MSM. It is important to map out MSM’s care trajectories and spaces and to identify all types of staff working within them, including non-medical staff, and enrol them in stigma reduction interventions

High and low suicidality in Europe: a fine-grained comparison of France and Spain within the ESEMeD surveys

Background: Suicidality risk-factors between countries with similar economic and religious background have been rarely compared, especially within genders. Methods: Lifetime prevalence of suicide ideation, plans, and attempts in the ESEMeD surveys were stratified on four separate groups: French women, Spanish women, French men, and Spanish men. Outcome odds-ratios (OR) were modelled within each group using logistic regression including demographic characteristics, lifetime mood/anxiety disorders, parental bonding, marital status, and health service-use. Results: Lifetime prevalence of suicide attempts was 3.4% in France (1.1% men, 5.4% women) and 1.5% in Spain (1.2% men, 1.7% women), with a significantly greater gender difference in France (p = 0.001). Regarding risk-factors, French women reported suicide attempt more commonly with authoritarian mothers (OR = 1.51; 95%CI = 1.04-2.18), unlike Spanish women (OR = 0.77; 95%CI = 0.51-1.15) (p < 0.001). Spanish men showed more than eight-times higher odds of suicide attempt with overprotecting mothers than French men (p = 0.03). General practitioner-(GP)-use was significantly protective of suicide attempt among Spanish women (OR = 0.08; 95%CI = 0.02-0.35) with no effect in French women (OR = 1.03; 95%CI = 0.54-2.00) (p = 0.01). No significant differences in the effect of marital status, any lifetime antidepressant use, mental disorders, or religiosity on suicide attempt were observed between France and Spain within gender-stratum. Limitations: Parental bonding is retrospective and potentially influenced by mental state. Response rate was considerably lower in France than in Spain. Conclusions: Suicidality risk-factors play different roles across genders between France and Spain. Parental bonding dimensions may be interpreted differently according to country, underlining cultural importance. As recommended by WHO, mental health decisions must involve GPs in conjunction with psychiatrists or psychologists

Photoinduced fluidity in chalcogenide glasses at low and high intensities: A model accounting for photon efficiency

International audienceDetailed measurements of photoinduced fluidity in Ge-Se glasses were performed using a novel shear relaxation test in torsion mode. It is shown that photofluidity is significant even at a very low intensity and that there is no apparent threshold for activating the photostructural processes. Instead, the mechanism of photofluidity is described as a cumulative process involving photoinduced motions of every atom within the irradiated volume. Based on this assumption, a model is proposed, which is shown to accurately predict the power and wavelength dependence of photofluidity using a single fitting parameter n. The factor n represents the photon efficiency for inducing an atomic motion. Photofluidity experiments performed on glass fibers of various mean coordination number indicate that the process is rapidly reduced in overconstrained glasses. The values of n obtained for these glasses correlate remarkably well with the mean coordination dependence of other photostructural changes (photodarkening, photoexpansion). This indicates that the model is physically sound. Moreover, the model is shown to quantitatively describe photofluidity data from other glass systems from literature, therefore suggesting that it could be universally applied to all chalcogenide glasses

An assessment of bicycle frame behaviour under various load conditions using numerical simulations

This paper outlines the use of a finite element model to simulate the behaviour for a standard steel bicycle frames under a range of measured load cases. These load cases include those measured both in the laboratory setting and also in the field, and include loads transmitted at key areas such as the dropouts and hub, the bottom bracket and drive, the headset and handlebars, and the seat post and saddle. The load cases analysed include static representations of dynamic bump situations which occur sporadically and also those which occur constantly or regularly such as those generated at the drive and handlebars during climbing or cruising. The resulting stresses within the bicycle are analysed in the context of frame performance relating to static and fatigue strengths and are also compared to similar load cases presented in the literature. Further research is required to understand the influence of tube profiles on frame strength, and to analyse the modes of failure for various bicycle designs and materials used under typical and extreme usage in order to understand the implications of design on safety

Association of childhood adversities and early-onset mental disorders with adult-onset chronic physical conditions

CONTEXT: The physical health consequences of childhood psychosocial adversities may be as substantial as the mental health consequences, but whether this is the case remains unclear because much prior research has involved unrepresentative samples and a selective focus on particular adversities or physical outcomes. The association between early-onset mental disorders and subsequent poor physical health in adulthood has not been investigated. OBJECTIVE: To investigate whether childhood adversities and early-onset mental disorders are independently associated with increased risk of a range of adult-onset chronic physical conditions in culturally diverse samples spanning the full adult age range. DESIGN: Cross-sectional community surveys of adults in 10 countries. SETTING: General population. PARTICIPANTS: Adults (ie, aged ≥18 years; N = 18 303), with diagnostic assessment and determination of age at onset of DSM-IV mental disorders, assessment of childhood familial adversities, and age of diagnosis or onset of chronic physical conditions. MAIN OUTCOME MEASURES: Risk (ie, hazard ratios) of adult-onset (ie, at age >20 years) heart disease, asthma, diabetes mellitus, arthritis, chronic spinal pain, and chronic headache as a function of specific childhood adversities and early-onset (ie, at age <21 years) DSM-IV depressive and anxiety disorders, with mutual adjustment. RESULTS: A history of 3 or more childhood adversities was independently associated with onset of all 6 physical conditions (hazard ratios, 1.44 to 2.19). Controlling for current mental disorder made little difference to these associations. Early-onset mental disorders were independently associated with onset of 5 physical conditions (hazard ratios, 1.43 to 1.66). CONCLUSIONS: These results are consistent with the hypothesis that childhood adversities and early-onset mental disorders have independent, broad-spectrum effects that increase the risk of diverse chronic physical conditions in later life. They require confirmation in a prospectively designed study. The long course of these associations has theoretical and research implications

Seismic structure and activity of the north-central Lesser Antilles subduction zone from an integrated approach: similarities with the Tohoku forearc

The 300 km long north-central segment of the Lesser Antilles subduction zone, including Martinique and Guadeloupe islands has been the target of a specific approach to the seismic structure and activity by a cluster of active and passive offshore-onshore seismic experiments coordinated within the ¿Thales was right¿ proposal to the European Union action (Laigle et al., Tectonophys., in rev.) The top of the subducting plate can be followed under the wide accretionary wedge by a dense grid of dip- and strike-lines of multichannel reflection seismics. This reveals the hidden updip limit of the contact of the upper plate crustal backstop thrust onto the slab. Two OBS refraction seismic profiles constrained a 26 km large crustal thickness from the volcanic arc throughout the forearc domain (Kopp et al., EPSL, 2011). These new observations imply a three times larger width of the potential interplate seismogenic zone under the marine domain of the Caribbean plate with respect to a regular intra-oceanic subduction zone, in the common assumption that the upper plate Moho contact on the slab is a proxy of its downdip limit. Towards larger depth under the mantle corner, the top of the slab imaged from the conversions of teleseismic body-waves and the locations of earthquakes from the dense temporary array of 80 OBS and land seismometers appears with kinks which increase the dip from 10-20° under the forearc domain, to 60° on the segment from 70 km depth down to under the volcanic arc. There, at 140 km depth just north of Martinique the 2007 M 7.4 earthquake, largest for half a century, was accompanied by an increased seismic activity over the whole depth range, which provides a new focused image thanks to the OBS and land deployments. A double-planed dipping slab seismicity is thus now resolved, as originally discovered in Tohoku ( NE Japan) and since in some other subduction zones. Other types of seismic activity uniquely observed in Tohoku, are resolved now here, such as ¿supraslab¿ earthquakes with normal-faulting focal mechanisms reliably located in the mantle corner and ¿deep flat-thrust¿ earthquakes at 45 km depth on the interplate fault under the Caribbean plate forearc mantle. None such types of seismicity should occur under the paradigm of a regular peridotitic mantle of the upper plate which is serpentinized by the fluids provided from the dehydrating slab beneath, and which is commonly considered as limiting the downward extent of the interplate seismic coupling. If the upper plate here comprised lithospheric segments related to the earlier formation of the Caribbean oceanic plateau by the material advection from a mantle plume, it could then be underlain by a correspondingly modified, heterogeneous mantle, which may impose regions of stick-slip behaviour on the interplate under the mantle corner among stable-gliding areas. The Tohoku 2011 M9 earthquake was unexpected not only in its slip reaching to the trench, but also in its slip reaching far under the mantle corner against the serpentinization decoupling paradigm, and its structural setting may be revisited for resolving corresponding structural heterogeneityPeer Reviewe