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The tracking of pupils by ability into elite and nonelite schools represents a controversial policy in many countries. There is no consensus on how large the elite track should be and little agreement on the effects of any further increase in its size. This paper presents a natural experiment where the increase in the size of the elite track was followed by a significant improvement in average educational outcomes. This experiment provides a rare opportunity to isolate the overall effect of allowing entry to the elite track for a group that was previously only at the margin of being admitted. (Contains 8 figures, 7 tables and 31 footnotes.)

Abstract: Bark beetles are notorious pests of natural and planted forests causing extensive damage. These insects depend on dead or weakened trees but can switch to healthy trees during an outbreak as mass-attacks allow the beetle to overwhelm tree defences. Climatic events like windstorms are known to favour bark beetle outbreaks because they create a large number of breeding sites, i.e., weakened trees and for this reason, windthrown timber is generally preventively harvested and removed. In December 1999, the southwest of France was struck by a devastating windstorm that felled more that 27millionm3of timber. This event offered the opportunity to study large-scale spatial pattern of trees attacked by the bark beetle Ips sexdentatus and its relationship with the spatial location of pine logs that were temporally stored in piles along stand edges during the post-storm process of fallen tree removal. The study was undertaken in a pure maritime pine forest of 1300ha in 2001 and 2002. We developed a landscape approach based on a GIS and a complete inventory of attacked trees. During this study more than 70% of the investigated stands had at least one tree attacked by I. sexdentatus. Spatial aggregation prevailed in stands with attacked trees. Patches of attacked trees were identified using a kernel estimation procedure coupled with randomization tests. Attacked trees formed patches of 500–700m2 on average which displayed a clumped spatial distribution. Log piles stemming from the sanitation removals were mainly distributed along the large access roads and showed an aggregated spatial pattern as well. The spatial relationship between patches of attacked trees and log pile storage areas was analyzed by means of the Ripley’s statistic that revealed a strong association at the scale of the studied forest. Our results indicated that bark beetle attacks were facilitated in the vicinity of areas where pine logs were stored. The spatial extent of this relationship was >1000m. Similar results were obtained in 2001 and 2002 despite differences in the number and spatial distribution of attacked trees. The presence of a strong “facilitation effect” suggests that log piles should be removed quickly in order to prevent outbreaks of bark beetles. [Copyright &y& Elsevier]

Objectives: Transcatheter aortic valve implantation (TAVI) has emerged as an effective treatment for high-risk patients with severe aortic stenosis (AS). The aim of our study was to compare the prevalence, characteristics and outcomes of high-risk patients treated prior to and after the availability of TAVI in our high-volume surgical institution., Methods: Among 879 consecutive patients treated 2 years before ('pre-TAVI era') and after ('modern era') the availability of TAVI in our institution, 83 patients were at high risk [defined by logistic European System for Cardiac Operative Risk Evaluation (EuroSCORE) >20%]., Results: Among all patients treated for severe AS, the prevalence of high-risk patients was higher in the modern era (12.7 vs 4.9%, P < 0.0001). In the modern era, high-risk patients were treated by TAVI in 89% of cases. Despite similar logistic EuroSCORE (34.9 vs 34%, P = 0.96), the clinical characteristics of these patients have evolved: high-risk patients in the modern era were older (85.3 ± 5.9 vs 78.5 ± 6.5 years, P = 0.0005) and presented more frequently with New York Heart Association class III-IV (92.3 vs 61.1%, P = 0.003), while high-risk patients treated by surgical aortic valve replacement in the pre-TAVI era presented more frequently with a critical preoperative status (33.3 vs 7.7%, P = 0.01), lower left ventricular ejection fraction (41 ± 14 vs 49 ± 15%, P = 0.05) and a history of recent myocardial infarction (27.8 vs 6.1%, P = 0.02). The overall 1-year survival was not different for high-risk patients treated in the pre-TAVI era or in the modern era (61 ± 11 vs 68 ± 6%, P = 0.52)., Conclusions: The availability of TAVI has increased the prevalence of high-risk patients treated for severe AS and changed the clinical features of this kind of patients who were rarely surgically treated before. The 1-year survival was similar between pre-TAVI and modern eras., (© The Author 2015. Published by Oxford University Press on behalf of the European Association for Cardio-Thoracic Surgery. All rights reserved.)

Background: Transcatheter aortic-valve implantation (TAVI) is an emerging intervention for the treatment of high-risk patients with severe aortic stenosis and coexisting illnesses. We report the results of a prospective multicenter study of the French national transcatheter aortic-valve implantation registry, FRANCE 2., Methods: All TAVIs performed in France, as listed in the FRANCE 2 registry, were prospectively included in the study. The primary end point was death from any cause., Results: A total of 3195 patients were enrolled between January 2010 and October 2011 at 34 centers. The mean (±SD) age was 82.7±7.2 years; 49% of the patients were women. All patients were highly symptomatic and were at high surgical risk for aortic-valve replacement. Edwards SAPIEN and Medtronic CoreValve devices were implanted in 66.9% and 33.1% of patients, respectively. Approaches were either transarterial (transfemoral, 74.6%; subclavian, 5.8%; and other, 1.8%) or transapical (17.8%). The procedural success rate was 96.9%. Rates of death at 30 days and 1 year were 9.7% and 24.0%, respectively. At 1 year, the incidence of stroke was 4.1%, and the incidence of periprosthetic aortic regurgitation was 64.5%. In a multivariate model, a higher logistic risk score on the European System for Cardiac Operative Risk Evaluation (EuroSCORE), New York Heart Association functional class III or IV symptoms, the use of a transapical TAVI approach, and a higher amount of periprosthetic regurgitation were significantly associated with reduced survival., Conclusions: This prospective registry study reflected real-life TAVI experience in high-risk elderly patients with aortic stenosis, in whom TAVI appeared to be a reasonable option. (Funded by Edwards Lifesciences and Medtronic.).