Telecommuications reform in Cote d'Ivoire

This paper analyzes C?e d'Ivoire's experience with telecommunications liberalization and privatization. C?e d'Ivoire privatized its incumbent operator in 1997, and granted the newly privatized firm seven years of fixed-line exclusivity while introducing"managed competition"in the cellular market and free competition in value-added services (VAS). By March 2001, three cellular operators and a number of VAS providers had entered the market. Reform has thus significantly changed the landscape of C?e d'Ivoire's telecommunications sector and has brought with it tremendous improvement in sector performance. Between 1997 and 2001, fixed-line telephone penetration grew from 1.03 to 1.80 per hundred people, while mobile penetration skyrocketed from 0.26 to 4.46. But it is still too early to assess the validity of granting exclusivity to the incumbent operator. While penetration increased, the operator did not meet objectives regarding rural telephony and service quality. Moreover, fixed-line penetration increased in areas where the operator faced competition from mobile providers.Payment Systems&Infrastructure,Telecommunications Infrastructure,Broadcast and Media,ICT Policy and Strategies,Economic Theory&Research,ICT Policy and Strategies,Telecommunications Infrastructure,Economic Theory&Research,Broadcast and Media,Rural Communications

Spectroscopie de vibration infrarouge du silicium amorphe hydrogéné évaporé

Ce travail porte sur l’étude des configurations des liaisons Si-H des couches minces du silicium amorphe hydrogéné évaporé (a-Si:H) préparées dans un bâti ultra-vide (UHV). L’hydrogène atomique est obtenu à l’aide d’un plasma dans un tube à décharge dirigé vers le porte-substrat. Les fréquences de vibrations et la nature des liaisons Si-H ont été analysées à partir des mesures de spectroscopie infrarouge à transformée de Fourier.Mots-clés : silicium amorphe hydrogéné, absorption infrarouge, transformée de Fourie

Modélisation des conditions d’environnement des bocaux de culture in vitro : bocaux avec agar et vitroplants

La présente étude traite de la modélisation des conditions des plantes en culture in vitro. Lorsque des vitroplants sont introduits dans les bocaux,l'humidité de l'air intérieur varie en fonction de leur stade de développementet ce en accord avec les courbes expérimentales. Les variations diurnes du déficit de pression de vapeur (DPV) présentent un maximum pendant laphotopériode et un minimum pendant la nyctipériode. Par ailleurs, grâce à la prise en compte des réservoirs de la plante, le modèle permet de décrire la déshydratation et la réhydratation des tissus, ce qui est potentiellement d'un intérêt pratique. Au cours du cycle diurne, la teneur en eau relative varie entre 75 et 90 %. Les flux d'eau dans la plante concordent bien avec les variations de la teneur en eau du réservoir plante et caractérisent bien les deux types de régimes de circulation de l'eau dans la plante : le régime de flux conservatif et le régime de flux non conservatif.Mots-clés : Modélisation, culture in vitro, humidité de l'air intérieur, réservoir-plante, déshydratation, réhydratatio

Modeling the microclimate inside a vessel in in vitro culture : vessel with agar

Numerical simulations show that variations in vessel internal humidity was sensitive to transfer coefficient, climatic conditions within the growth chamber, evaporation and condensation of water vapor on the walls of the vessel. The variations in water vapor pressure deficits (VPD) (low during the nyctiperiod and high during the photoperiod) were well explained by a free convection model, which took into account temperature differences. Finally, the results show the necessity to construct containers with variable openings and growth chambers in which bioclimatic conditions can be controlled.Les simulations numériques révèlent que les variations de l\'humidité interne ont été sensibles au coefficient d\'échange de vapeur d\'eau, aux conditions climatiques de la chambre de culture et aux phénomènes d\'évaporation et de condensation de vapeur d\'eau sur les parois des bocaux. Par ailleurs, il a été établi que le «créneau» de déficit de pression de vapeur (DPV) de l\'air intérieur (palier de DPV faible en nyctipériode et palier de DPV élevé en photopériode) a été bien imité en mode convectif libre qui tient compte des écarts de températures. Ainsi, ces résultats montrent la nécessité de construire des récipients à ouverture variable et des chambres de culture dans lesquelles les facteurs bioclimatiques des plantes peuvent être maîtrisés. Keywords: Agar, in vitro culture, microclimate, modeling, transfer coefficient./Agar, culture in vitro, microclimat, modélisation, coefficient d\'échange.Sciences & Nature Vol. 4 (1) 2007: pp. 75-8

How to Make the TAVI Pathway More Efficient

Transcatheter aortic valve implantation (TAVI) has been in use for 16 years. As there has been a rapid expansion in its use, there is a need to optimise TAVI programmes to ensure efficiency. In this article, the authors discuss the reasons why clinicians need to make the TAVI pathway more efficient and describe the most important steps to take from screening to early discharge, including procedural optimisation

Expert Consensus on Sizing and Positioning of SAPIEN 3/Ultra in Bicuspid Aortic Valves

Severe aortic stenosis patients with bicuspid anatomy have been excluded from the major transcatheter aortic valve replacement (TAVI) randomized clinical trials. As a result, there is no official recommendation on bicuspid TAVI. A panel of bicuspid experts was created to fill this gap. In this consensus statement, an algorithm is proposed to guide the choice of surgery or TAVI within this complex patient population, depending on aortic dilatation, age, surgical risk score, and anatomy. A step-by-step guide for sizing and positioning of the SAPIEN 3/Ultra TAVI bioprostheses is presented. Annular sizing remains the primary strategy in most bicuspid patients. However, some anatomies may require sizing at the supra-annular level, for which patients the panel recommends the circle method, a dedicated sizing and positioning approach for SAPIEN 3/Ultra. The consensus provides valuable pre-operative insights on the interactions between SAPIEN 3/Ultra and the bicuspid anatomy; understanding the valve-anatomy relationship is critical to avoid complications and to optimize outcomes for patients.Peer reviewe

Transcatheter heart valve selection and permanent pacemaker implantation in patients with pre-existent right bundle branch block

Background-Right bundle branch block is an established predictor for new conduction disturbances and need for a permanent pacemaker (PPM) after transcatheter aortic valve replacement. The aim of the study was to evaluate the absolute rates of transcatheter aortic valve replacement related PPM implantations in patients with pre-existent right bundle branch block and categorize for different transcatheter heart valves. Methods and Results-We pooled data on 306 transcatheter aortic valve replacement patients from 4 high-volume centers in Europe and selected those with right bundle branch block at baseline without a previously implanted PPM. Logistic regression was used to evaluate whether PPM rate differed among transcatheter heart valves after adjustment for confounders. Mean age was 83±7 years and 63% were male. Median Society of Thoracic Surgeons score was 6.3 (interquartile range, 4.1-10.2). The following transcatheter valve designs were used: Medtronic CoreValve (n=130; Medtronic, Minneapolis, MN); Edwards Sapien XT (ES-XT; n=124) and Edwards Sapien 3 (ES-3; n=32; Edwards Lifesciences, Irvine, CA); and Boston Scientific Lotus (n=20; Boston Scientific Corporation, Marlborough, MA). Overall permanent pacemaker implantation rate post-transcatheter aortic valve replacement was 41%, and per valve design: 75% with Lotus, 46% with CoreValve, 32% with ES-XT, and 34% with ES-3. The indication for PPM implantation was total atrioventricular block in 98% of the cases. Lotus was associated with a higher PPM rate than all other valves. PPM rate did not differ between ES-XT and ES-3. Ventricular paced rhythm at 30-day and 1-year follow-up was present in 81% at 89%, respectively. Conclusions-Right bundle branch block at baseline is associated with a high incidence of PPM implantation for all transcatheter heart valves. PPM rate was highest for Lotus and lowest for ES-XT and ES-3. Pacemaker dependency remained high during followup

Sex Differences in Outcomes After Percutaneous Coronary Intervention or Coronary Artery Bypass Graft for Left Main Disease: From the DELTA Registries

Background Controversy exists over whether sex has significant interaction with revascularization strategy for unprotected left main coronary artery disease. Higher mortality has been reported among women treated with percutaneous coronary intervention compared with coronary artery bypass grafting. Methods and Results The DELTA (Drug-Eluting Stents for Left Main Coronary Artery Disease) and DELTA-2 registries are international, multicentric registries evaluating the outcomes of subjects undergoing coronary revascularization for unprotected left main coronary artery disease. The primary outcome was a composite of death, myocardial infarction, or cerebrovascular accidents. The population consisted of 6253 patients, including 1689 (27%) women. Women were older and more likely to have diabetes and chronic kidney disease than men (P<0.05). At a median follow-up of 29 months (interquartile range 12-49), a significant interaction between sex and revascularization strategy was observed for the primary end point (pint=0.012) and all-cause death (pint=0.037). Among women, compared with percutaneous coronary intervention, coronary artery bypass grafting was associated with lower risk of the primary end point (event rate 9.5% versus 15.3%; adjusted hazard ratio [AHR], 0.53; 95% CI, 0.35-0.79, P<0.001) and all-cause death (event rate 5.6% versus 11.7% AHR, 0.50; 95% CI, 0.30-0.82) and no significant differences were observed in men. Conclusions In women undergoing coronary revascularization for unprotected left main coronary artery disease, coronary artery bypass grafting was associated with lower risk of death, myocardial infarction, or cerebrovascular accidents whereas no significant differences between coronary artery bypass grafting and percutaneous coronary intervention were observed in men. Further dedicated studies are needed to determine the optimal revascularization strategy in women with unprotected left main coronary artery disease. Keywords: cardiovascular disease in women; coronary revascularization; unprotected left main coronary artery disease

Transcatheter aortic valve implantation in failed bioprosthetic surgical valves.

IMPORTANCE: Owing to a considerable shift toward bioprosthesis implantation rather than mechanical valves, it is expected that patients will increasingly present with degenerated bioprostheses in the next few years. Transcatheter aortic valve-in-valve implantation is a less invasive approach for patients with structural valve deterioration; however, a comprehensive evaluation of survival after the procedure has not yet been performed. OBJECTIVE: To determine the survival of patients after transcatheter valve-in-valve implantation inside failed surgical bioprosthetic valves. DESIGN, SETTING, AND PARTICIPANTS: Correlates for survival were evaluated using a multinational valve-in-valve registry that included 459 patients with degenerated bioprosthetic valves undergoing valve-in-valve implantation between 2007 and May 2013 in 55 centers (mean age, 77.6 [SD, 9.8] years; 56% men; median Society of Thoracic Surgeons mortality prediction score, 9.8% [interquartile range, 7.7%-16%]). Surgical valves were classified as small (≤21 mm; 29.7%), intermediate (&gt;21 and &lt;25 mm; 39.3%), and large (≥25 mm; 31%). Implanted devices included both balloon- and self-expandable valves. MAIN OUTCOMES AND MEASURES: Survival, stroke, and New York Heart Association functional class. RESULTS: Modes of bioprosthesis failure were stenosis (n = 181 [39.4%]), regurgitation (n = 139 [30.3%]), and combined (n = 139 [30.3%]). The stenosis group had a higher percentage of small valves (37% vs 20.9% and 26.6% in the regurgitation and combined groups, respectively; P = .005). Within 1 month following valve-in-valve implantation, 35 (7.6%) patients died, 8 (1.7%) had major stroke, and 313 (92.6%) of surviving patients had good functional status (New York Heart Association class I/II). The overall 1-year Kaplan-Meier survival rate was 83.2% (95% CI, 80.8%-84.7%; 62 death events; 228 survivors). Patients in the stenosis group had worse 1-year survival (76.6%; 95% CI, 68.9%-83.1%; 34 deaths; 86 survivors) in comparison with the regurgitation group (91.2%; 95% CI, 85.7%-96.7%; 10 deaths; 76 survivors) and the combined group (83.9%; 95% CI, 76.8%-91%; 18 deaths; 66 survivors) (P = .01). Similarly, patients with small valves had worse 1-year survival (74.8% [95% CI, 66.2%-83.4%]; 27 deaths; 57 survivors) vs with intermediate-sized valves (81.8%; 95% CI, 75.3%-88.3%; 26 deaths; 92 survivors) and with large valves (93.3%; 95% CI, 85.7%-96.7%; 7 deaths; 73 survivors) (P = .001). Factors associated with mortality within 1 year included having small surgical bioprosthesis (≤21 mm; hazard ratio, 2.04; 95% CI, 1.14-3.67; P = .02) and baseline stenosis (vs regurgitation; hazard ratio, 3.07; 95% CI, 1.33-7.08; P = .008). CONCLUSIONS AND RELEVANCE: In this registry of patients who underwent transcatheter valve-in-valve implantation for degenerated bioprosthetic aortic valves, overall 1-year survival was 83.2%. Survival was lower among patients with small bioprostheses and those with predominant surgical valve stenosis