SIMULATION OF THE PRE- AND POST-TRANSIT TIME OF FLIGHT METHODS IN AMORPHOUS SILICON-LIKE. N+-I-P+ -CELLS SIMULATION DES METHODES DE PRE- ET POST-TRANSIT DE LA TECHNIQUE TEMPS DE VOL POUR LES CELLULES N+-I-P+ EN MATERIAU DE TYPE a-Si:H.

In this paper, we study, by numerical simulation, the Transient Photocurrent (TPC) resulting from the application of the 'TimeOf Flight' (TOF) technique to a-Si:H n+-i-p+ cell by using a typical Density Of States (DOS) of amorphous silicon. The preandpost-transit methods, currently used to probe the energy distribution of localised states, are then applied to reconstruct theproposed DOS from the simulated TPC. We demonstrate that the two methods of reconstruction are complementary andprovide an efficient tool of determining the transit time

MECANISMES DE FORMATION DES DEFAUTS DANS LE a-Si:H A L'EQUILIBRE ET SOUS L'ILLUMINATION. DEFECT FORMATION MECHANISMS IN a-Si:H AT EQUILIBRIUM STATE AND UNDER LIGHT-SOAKING

RESUMEA l'équilibre thermodynamique, la création des défauts dans la structure du silicium amorphe hydrogéné (a-Si:H) est le résultatde la conversion des liaisons faibles en liaisons pendantes provoquée par la diffusion de l'hydrogène. L'application de la loi del'effet de masse à cette réaction suivant le modèle defect pool permet la détermination de la densité d'états des défauts dans legap d'énergie. Lorsque le matériau est exposé à la lumière, la densité totale des défauts augmente. Nous proposons un nouveaumodèle pour simuler la cinétique de création des défauts induits par la lumière selon lequel l'évolution de la densité totale desdéfauts se trouve en accord avec les mesures expérimentales généralement observées.ABSTRACTAt thermodynamic equilibrium state, the defect creation process in hydrogenated amorphous silicon (a-Si:H) is the result ofdangling bonds weak bonds conversion induced by hydrogen diffusion. The application of the law of mass action to thisreaction according to defect pool model allows the determination of the defect state density in the gap. When the material isexposed to light, the total defect density increases. We propose a new model to simulate the light induced defect creationkinetic where the total defect density evolution is found to agree with observed experimental measurements

Contact Force and Scanning Velocity during Active Roughness Perception

Haptic perception is bidirectionally related to exploratory movements, which means that exploration influences perception, but perception also influences exploration. We can optimize or change exploratory movements according to the perception and/or the task, consciously or unconsciously. This paper presents a psychophysical experiment on active roughness perception to investigate movement changes as the haptic task changes. Exerted normal force and scanning velocity are measured in different perceptual tasks (discrimination or identification) using rough and smooth stimuli. The results show that humans use a greater variation in contact force for the smooth stimuli than for the rough stimuli. Moreover, they use higher scanning velocities and shorter break times between stimuli in the discrimination task than in the identification task. Thus, in roughness perception humans spontaneously use different strategies that seem effective for the perceptual task and the stimuli. A control task, in which the participants just explore the stimuli without any perceptual objective, shows that humans use a smaller contact force and a lower scanning velocity for the rough stimuli than for the smooth stimuli. Possibly, these strategies are related to aversiveness while exploring stimuli

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Background: Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. // Methods: We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung's disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. // Findings: We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung's disease) from 264 hospitals (89 in high-income countries, 166 in middle-income countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in low-income countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. // Interpretation: Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between low-income, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030