Inside the 'Black Box' of Project STAR: Estimation of Peer Effects Using Experimental Data

The credible identification of endogenous peer group effects -- i.e. social multiplier or feedback effects -- has long eluded social scientists. We argue that such effects are most credibly identified by a randomly assigned social program which operates at differing intensities within and between peer groups. The data we use are from Project STAR, a class size reduction experiment conducted in Tennessee elementary schools. In these data, classes were comprised of varying fractions of students who had previously been exposed to the Small class treatment, creating class groupings of varying experimentally induced quality. We use this variation in class group quality to estimate the spillover effect. We find that when allowance is made for this 'feedback' effect of prior exposure to the Small class treatment, the peer effects account for much of the total experimental effects in the later grades, and the direct class size effects are rendered substantially smaller.Peer Effects; Data with a Group Structure; Organization of Schooling; Experimental Evidence

High-resolution periodic mode shapes identification for wind turbines

The stability analysis of in-operation wind turbines is a very important topic, that has received considerable attention in the last years. Many identification algorithms have been developed to estimate frequencies and damping ratios, but very few papers have been dedicated to the mode shapes. The knowledge of high-resolution mode shapes could be exploited for several applications including model validation, accurate description of the vibratory content of a machine and spatially-accurate damage detection. In this work, we will present a procedure to compute the high-resolution periodic mode shapes of a wind turbine, and apply it to a high-fidelity wind turbine model. The results show that this methodology is able to identify the first low-damped modes of the system with good accuracy

Root and crown tot of olive caused dy Phytophthora spp.

Phytophthora root and crown rot has been traditionally considered a minor disease of olive. However, in recent years it has been recognized as an emerging problem in several olive-growing countries such as Australia, Italy and Spain probably as a consequence of the expansion of plantings in new areas with heavy soils and the more intensive use of irrigation in both olive nurseries and commercial groves. The disease has been reported from most olive-growing countries and is caused by several soil -borne species of Phytophthora, including P. cinnamomi, P. citricola, P. cryptogea, P. drechsleri, P. gonapodyides, P. inundata, P. megasperma,P. nicotianae and P.palmivora. Diagnosis is currently based on the isolation and identification of isolates by both traditional and molecular methods. New molecular techniques are currently available that could be applied for both the identification of isolates and Phytophthora infections directly in host-tissues as well as insoil and water samples. A number of dedicated databases could improve the efficiency of these techniques. Moreover, DNA analysis has greatly contributed to phylogenetic studies of Phytophthora. Control of Phytophthora root and crown rot of olive is mainly based on preventive measures

Detection of rotor imbalance, including root cause, severity and location

This paper presents a new way of detecting imbalances on wind turbine rotors, by using a harmonic analysis of the rotor response in the fixed frame. The method is capable of distinguishing among different root causes of the imbalance. In addition, the imbalance severity and location, i.e. the affected blade, can be identified. The automatic classification of the imbalance problem is obtained by using a neural network. The performance of the method is illustrated with the help of different fault scenarios, within a high-fidelity simulation environment

Inside the ‘Black Box’ of Project STAR: Estimation of Peer Effects Using Experimental Data

The credible identification of endogenous peer group effects -- i.e. social multiplier or feedback effects -- has long eluded social scientists. We argue that such effects are most credibly identified by a randomly assigned social program which operates at differing intensities within and between peer groups. The data we use are from Project STAR, a class size reduction experiment conducted in Tennessee elementary schools. In these data, classes were comprised of varying fractions of students who had previously been exposed to the Small class treatment, creating class groupings of varying experimentally induced quality. We use this variation in class group quality to estimate the spillover effect. We find that when allowance is made for this 'feedback' effect of prior exposure to the Small class treatment, the peer effects account for much of the total experimental effects in the later grades, and the direct class size effects are rendered substantially smaller

A new approach in the monitoring of the phytosanitary conditions of forests: the case of oak and beech stands in the Sicilian Regional Parks

L'obiettivo del presente studio è stato quello di esaminare lo stato fitosanitario delle quercete e faggete dei tre Parchi Regionali Siciliani (Parco dell'Etna, Parco delle Madonie, Parco dei Nebrodi). Lo studio è stato condotto individuando delle aree di saggio, popolamenti forestali omogenei sotto l'aspetto floristico, ecologico e fitosanitario. Complessivamente sono state delimitate 81 aree di saggio, di cui 54 quercete e 27 faggete. La condizione fitosanitaria di ogni essenza arborea all'interno della rispettiva area di saggio è stata espressa con un indice numerico denominato “classe fitosanitaria” (PC). I popolamenti di quercia hanno mostrato un elevato grado di sofferenza, con alberi sintomatici nell’85% delle aree di saggio. I popolamenti di faggio hanno mostrato una situazione di maggiore stabilità, ad eccezione delle faggete del parco dei Nebrodi che apparivano molto degradate. Sul genere Quercus, sono stati osservati sintomi di infezioni di patogeni fungini comuni nelle foreste delle aree temperate e Mediterranee, quali Biscogniauxia mediterranea, Polyporus sp., Fistulina hepatica, Mycrosphaera alphitoides ed Armillaria sp., mentre su faggio sono state osservate infezioni di Biscogniauxia nummularia, Fomes fomentarius e Neonectria radicicola. Sono state altresì individuate 22 aree che vengono proposte come aree di saggio permanenti dello stato fitosanitario delle foreste nei tre parchi.The objective of this study was to investigate the health conditions of oak and beech stands in the three Regional Parks of Sicily (Etna, Madonie and Nebrodi). A total of 81 sampling areas were investigated, 54 in oak stands and 27 in beech stands. The phytosanitary conditions of each tree within the respective sampling area was expressed with a synthetic index namely phytosanitary class (PC). Oak stands showed severe symptoms of decline, with 85% of the sampling areas including symptomatic trees. In general, beech stands were in better condition, with the exception of Nebrodi Park, where trees showed severe symptoms of decline. On oak trees, infections of fungal pathogens were also observed, including Biscogniauxia mediterranea, Polyporus sp., Fistulina hepatica, Mycrosphaera alphitoides and Armillaria sp. By contrast, on beech trees Biscogniauxia nummularia, Fomes fomentarius and Neonectria radicicola were recognized. Furthermore, twenty-two permanent sampling areas were delimited with the aim of monitoring regularly the health conditions of forests in these three parks

A Keynesian perspective on the health economics of kidney transplantation would strengthen the value of the whole organ donation and transplantation service

BackgroundIn this study, the Keynesian principle "savings may be used as investments in resources" is applied to Kidney Transplantation (KT), contextualizing the whole Organs Donation and Transplantation (ODT) service as a unique healthcare entity. Our aim was to define the financial resources that may be acquired in the form of savings from the KT activity. MethodsWe analyzed registry and funding data for ODT in our region, between 2015 and 2019. Our hypotheses aimed to evaluate whether the savings would offset the Organ Donation (OD) costs, define the scope for growth, and estimate what savings could be generated by higher KT activity. To facilitate the evaluation of the resources produced by KT, we defined a coefficient generated from the combination of clinical outcomes, activity, and costs. ResultsThe ODT activity reached a peak in 2017, declining through 2018-2019. The savings matured in 2019 from the KT activity exceeded euro15 million while the OD costs were less than euro9 million. The regional KT activity was superior to the national average but inferior to international benchmarks. The estimated higher KT activity would produce savings between euro16 and 20 million. ConclusionThe financial resources produced by KT contribute to defining a comprehensive perspective of ODT finance. The optimization of the funding process may lead to the financial self-sufficiency of the ODT service. The reproducible coefficient allows a reliable estimate of savings, subsequently enabling adequate investments and budgeting. Applying such a perspective jointly with reliable estimates would establish the basis for an in-hospital fee-for-value funding methodology for ODT