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High yield multistep synthesis of stable and diversely functionalized phosphorus dendrimers is reported.

The LOFT mission concept is one of four candidates selected by ESA for the M3 launch opportunity as Medium Size missions of the Cosmic Vision programme. The launch window is currently planned for between 2022 and 2024. LOFT is designed to exploit the diagnostics of rapid X-ray flux and spectral variability that directly probe the motion of matter down to distances very close to black holes and neutron stars, as well as the physical state of ultra-dense matter. These primary science goals will be addressed by a payload composed of a Large Area Detector (LAD) and a Wide Field Monitor (WFM). The LAD is a collimated (, Proceedings of SPIE, Vol. 8443, Paper No. 8443-85, 2012

A computer-intensive method for error estimate based on “synchronous” statistical resampling of overlapping blocks of data is proposed in the context of Monte Carlo renormalization group calculations. It appears stable and well behaved even for relatively small data sets, enabling one to avoid the problems of ordinary procedures based on subseries values.

Alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) glutamate receptor antagonists are of potential interest for the treatment of certain acute and chronic neurodegenerative diseases, including amyotrophic lateral sclerosis. Here, we describe the synthesis and pharmacological properties of 9-carboxymethyl-4-oxo-5H,10H-imidazo[1,2-a]indeno[1,2-e]pyrazin-2-phosphonic acid (RPR 119990). The compound displaced [3H]AMPA from rat cortex membranes with a K(i) of 107 nM. In oocytes expressing human recombinant AMPA receptors, RPR 119990 depressed ion flux with a K(B) of 71 nM. The antagonist properties of this compound were confirmed on rat native AMPA receptors in cerebella granule neurons in culture and in hippocampal slices where it antagonized electrophysiological responses with IC50 values of 50 and 93 nM, respectively. RPR 119990 antagonized hippocampal evoked responses in vivo, demonstrating brain penetration at active concentrations. RPR 119990 is a potent anticonvulsant in the supramaximal electroshock in the mouse with an ED50 of 2.3 mg/kg 1 h post s.c. administration, giving it a workably long action. Pharmacokinetic studies show good passage into the plasma after subcutaneous administration, whereas brain penetration is low but with slow elimination. This compound was found active in a transgenic mouse model of familial amyotrophic lateral sclerosis (SOD1-G93A) where it was able to improve grip muscle strength and glutamate uptake from spinal synaptosomal preparations, and prolong survival with a daily dose of 3 mg/kg s.c.

The over-stimulation of excitatory amino acid receptors such as the glutamate AMPA receptor has been suggested to be associated with neurodegenerative disorders. Here we describe an original series of readily water soluble 4-oxo-imidazo[1,2-a] indeno[1,2-e]pyrazin-8- and -9-carboxylic (acetic) acid derivatives. One of these compounds, 4f, exhibited nanomolar binding affinity, potent competitive antagonism at the ionotropic AMPA receptor and a long duration of anticonvulsant activity after administration by parenteral route in vivo.

A novel series of 2-substituted-4,5-dihydro-4-oxo-4H-imidazo[1,2-a]indeno[1,2-e]pyrazine derivatives was synthesised. One of them, 4e-a highly water soluble compound exhibited a nanomolar affinity and demonstrated competitive antagonist properties at the ionotropic AMPA receptors. This compound also displayed potent anticonvulsant properties against electrically or sound-induced convulsions in mice after systemic administration, thus suggesting adequate brain penetration.

Dehydrodimerization is suppressed completely in the presence of radicophiles such as cd-substituted olefins. Particularly α-t-butylmercaptoacrylonitrile (TBMA) has been examined as a trapping agent for carbon centered radicals. The adducts dimerize thus building C4-bridges between the original radicals. This general principle is synthetically useful as demonstrated by C4-bridging of alkanes, ethers, amines, amides, aldehydes and ketones.

This paper describes the results of a questionnaire given to the students of the schools of Emilia-Romagna who participated in the Banca d’Italia-Miur project in the field of economic and financial education. The results show an important increase in the knowledge of students following a 10-hour course held to school teachers by teachers of the Bank of Italy. In particular, between the pre- and post- teaching activities carried out by their teachers in the classroom, students have increased the number of correct answers by about 5 units in a questionnaire of 30 questions and compared to the improvement obtained by a group of students not interested in the teaching activity related to the course of the Bank of Italy. The results are robust to a set of controls suggested by the literature on the subject.

Three atypical patterns of cardiac failure and pulmonary edema, as frequently seen in chronic obstructive pulmonary diseases, are described; I. regional; II. miliary-like; III. Swiss-cheese like. Their importance in early diagnosis of pulmonary edema is discussed in the light of a review of a series of 98 patients whose pulmonary function was also investigated. Examples and statistical data are drown from this series.

Dehydrodimerization is suppressed completely in the presence of radicophiles such as cd-substituted olefins. Particularly α-t-butylmercaptoacrylonitrile (TBMA) has been examined as a trapping agent for carbon centered radicals. The adducts dimerize thus building C4-bridges between the original radicals. This general principle is synthetically useful as demonstrated by C4-bridging of alkanes, ethers, amines, amides, aldehydes and ketones.

Captodative olefins efficiently trap both electrophilic or nucleophilic radicals, i.e. various thiyl, acetyl, acetamidomethyl and N-methylanilinomethyl radicals. In the first three cases, good yields of adduct-dimers 4 are formed and these reactions are preparatively useful. In the last case when anilinomethyl radicals are formed at 140°, also dismutation or double adduct 5 formation may occur depending on the choice of c and d groups in 2.

The aim of the article is to propose a Bayesian estimation through Markov chain Monte Carlo of a multidimensional item response theory model for graded responses with an additive structure with correlated latent traits. A simulation study is conducted to evaluate the model parameter recovery under different conditions (sample size, test and subtest length, number of response categories, and correlation structure). The results show that the parameters are well reproduced when the sample size is sufficiently large (n = 1, 000), while the worst recovery is observed for small sample size (n = 500), and four response categories with a short number of test items.

Background: Recently, the study of territorial differences in educational outcomes has assumed a particular importance for the policy strategies related to the socioeconomic conditions of different geographical areas. In Italy, international surveys for student assessments have introduced a regional stratification only recently, and regular national student assessments started only in 2008. Method: In this article, the reading performances of Italian students based on OECD-PISA 2009 are investigated, taking into account regional and macro-area partition. Student outcomes are explored by using a multilevel analysis, where school membership, socioeconomic and cultural background of students, and regional gross domestic product are introduced. Results: The results show that, despite the existence of a unified educational system in Italy, regional and macro-area differences in student reading achievements are consolidated and variability in performances among schools is especially noticeable. Comparisons based on national assessments by INVALSI at the end of compulsory school confirm these findings. Conclusion: Italian policy makers are advised to take into account these results to improve learning opportunities and to reduce educational gaps. In particular, targeted regional policies are needed to improve the mean performance especially in the Southern regions of Calabria, Campania, and Sicilia, and to strengthen the system equity in several regions, such as Emilia-Romagna. To decrease the school differences, possible suggestions are to postpone the choice of the school type (currently, at age 14) and to motivate good teachers to work in schools located in the worst socioeconomic and cultural environments.

The novelty of this study is to propose multidimensional item response theory (IRT) models for the investigation of heterogeneity in residents’ perceptions and attitudes toward the tourism industry. By following the social exchange theory, a sample of residents in the Romagna area (Italy) were invited to declare their agreement to some aspects related to benefits and costs of the tourism industry in 2010. The analysis suggests that the additive IRT model with two kind of latent variables (viz. the general latent trait measuring attitude toward tourism and two specific latent traits measuring perceptions on benefits and costs of tourism) fits the data adequately. Moreover, the estimated scores show that the tourism features are perceived differently by the residents, supporting the hypothesis that perceptions and attitudes change with regard to the individuals’ characteristics. Finally, the analysis proposes how the parameters of the IRT models can be interpreted in this new context.

The focus of this article is on the choice of suitable prior distributions for item parameters within item response theory (IRT) models. In particular, the use of empirical prior distributions for item parameters is proposed. Firstly, regression trees are implemented in order to build informative empirical prior distributions. Secondly, model estimation is conducted within a fully Bayesian approach through the Gibbs sampler, which makes estimation feasible also with increasingly complex models. The main results show that item parameter recovery is improved with the introduction of empirical prior information about item parameters, also when only a small sample is available.

La formazione di base, l'accesso al sapere e il successo formativo sono questioni di grande interesse in tema di politica del lavoro. Č noto come giŕ a partire dai primi anni di scuola lo status socio-economico e culturale delle famiglie eserciti un ruolo fondamentale come variabile esplicativa dei risultati conseguiti dagli studenti. Disporre di informazioni accurate non solo sugli esiti formativi, ma anche sulle caratteristiche dei contesti familiari, diventa quindi di particolare rilevanza nella definizione delle politiche scolastiche territoriali. In questo lavoro viene presentata una proposta metodologica per la costruzione di indicatore statistico dello status socio-culturale delle famiglie con riferimento ai dati di un'indagine dell'della Provincia di Bologna sugli esiti scolastici di un campione di studenti della scuola secondaria di II grado. Dalle analisi condotte emerge l'esistenza di un legame tra retroterra familiare e risultato scolastico. Nemmeno in una realtŕ ad alta scolaritŕ, quale quella bolognese la scuola sembra essere in grado di neutralizzare l'effetto di ambienti familiari sfavorevoli sul rendimento scolastico dei ragazzi.

This paper investigates Italian student performances based on the 2009 edition of the Programme for International Student Assessment (PISA), a survey conducted by Organization for Economic Cooperation and Development (OECD) in order to assess skills of 15-year-olds in schools with respect to reading, mathematical and scientific literacy. In particular, student outcomes are compared among different Italian regions, taking into account socio-economic background and school membership of students. The results show that, despite the existence of a unified educational system in Italy, regional differences are evident. However, taking the nested structure of data into account, it can be shown that the most part of the variability in student performances can be explained by differences at school level.

In the field of educational measurement, it often happens that tests consist of different subscales involving explicitly several dimensions. With the aim of estimating the test item psychometric properties and the candidate ability, item response theory (IRT) models are often used with multidimensional structure. In this work, a comparison among multidimensional models with different ability structures is conducted in a case study. In particular, data from Italian student assessments conducted at the end of the lower secondary school by INVALSI are taken into account.

In testing, item response theory models are widely used in order to estimate item parameters and individual abilities. However, even unidimensional models require a considerable sample size so that all parameters can be estimated precisely. The introduction of empirical prior information about candidates and items might reduce the number of candidates needed for parameter estimation. Using data for IQ measurement, this work shows how empirical information about items can be used effectively for item calibration and in adaptive testing. First, we propose multivariate regression trees to predict the item parameters based on a set of covariates related to the item-solving process. Afterwards, we compare the item parameter estimation when tree-fitted values are included in the estimation or when they are ignored. Model estimation is fully Bayesian, and is conducted via Markov chain Monte Carlo methods. The results are two-fold: (a) in item calibration, it is shown that the introduction of prior information is effective with short test lengths and small sample sizes and (b) in adaptive testing, it is demonstrated that the use of the tree-fitted values instead of the estimated parameters leads to a moderate increase in the test length, but provides a considerable saving of resources.

In educational and psychological measurement, the study of test dimensionality is a fundamental issue. The aim of the paper is to compare item response theory (IRT) models with different structures in the latent abilites, in the case of a test consisting of different subscales. In fact, a unidimensional model may not properly fit the data while multidimensional models, also assuming the existence of general and specific traits, may be more accurate. IRT models with a multidimensional ability structure are compared through simulation studies in order to understand their effective capability of recovering different test structures. Model estimation is conducted via Markov chain Monte Carlo (MCMC) methods, adopting a fully Bayesian approach. An application is also conducted on real data on Italian standardized student assessments.

it is well known from literature on teaching statistics that learning of this discipline gives better results if the students are involved in empirical problems. This paper describes the results of the National Olympic Games of Statistics at High School. The aim of this project is to encourage and stimulate students to develop statistical reasoning.

The paper deals with the investigation of gender differences in performances in mathematics for Italian students at the end of lower secondary school. The study is based on a new large-scale assessment test developed and administered by the National Evaluation Institute for the School System. Given the evidence in the literature which favors males, performances of female and male students are compared using different approaches. Scores proposed by educational experts based on item subgroups were considered, while a model-based approach was used within item response theory. The results revealed a significant advantage to males in overall performance, while no meaningful differences were observed with respect to item domain and type. An interpretable item map was developed crossing expert opinions with IRT abilities, and plausible proficiency levels were defined. According to the map-based student classification, a relatively lower percentage of females fell into the highest proficiency groups with respect to males.

Aspetti statistici per l’analisi e la lettura dei risultati PISA

Il lavoro si propone di ripercorrere alcune metodologie generali di analisi dei test per la valutazione degli apprendimenti, discutendo i risultati ottenuti in due casi di studio riguardanti le prove preparate dal Servizio Nazionale di Valutazione (SNV) dell’INVALSI per la classe seconda della scuola primaria. In particolare, viene descritto il processo di analisi dei pre-test attraverso l’utilizzo congiunto degli indicatori derivanti dalla Classical Test Theory e dei modelli di Item Response Theory.

Il rapporto presenta i risultati dell'analisi statistiche effettuate sulle risposte date dagli studenti al'Esame di Stato della scuola secondaria di primo grado, classe terza, anno 2007-2008. I dati forniti dall'Invalsi riguardano le risposte fornite alle prove standardizzate di italiano e matematica.

Item response theory (IRT) models have been developed in order to study the individual responses to a set of items designed to measure latent abilities. IRT is a measurement theory that was first formalized in the sixties with the fundamental work of Lord and Novick (1968) and it has a predominant role in educational assessment. An IRT model describes the relationship between the observable examinee’s performance in the test, typically in the form of responses to categorical items, and the unobservable latent ability. Therefore, IRT models can be included in the more general framework of latent variable modelling . IRT is used in all phases of test administration, from the test calibration to the estimation of individual abilities, in which the estimated item parameters are used to characterize the examinees. After a brief presentation of the main assumptions of IRT models, several aspects related to specific problems in the context of test administration are treated. Many advances have been introduced over the last few years, that allow both to support more complex models and to improve the esti-mation algorithms. In particular, issues on multidimensionality incomplete design and the inclusion of prior information are discussed, referring both to current literature and to some contributions of the authors. Particular attention is given to the use of the Gibbs sam-pler, in the Markov Chain Monte Carlo (MCMC) methods, for the estimation of IRT models. Finally, an application related to one of this topics is presented in the context of educational assessment

In this work, a combined use of different methods is proposed in order to evaluate mathematics students’ achievement within the Italian lower secondary school. Despite the increasing need for an objective assessment of student performance, a univocal approach still does not exist. By using data from the INVALSI standardized test administered in 2008 to Italian lower secondary school students, a joint approach of test score, latent trait and latent class analysis is proposed which highlights both item features and student differences properly. The methods show an effective capability of differentiating the examinees into three performance groups on the basis of the response patterns.

Recently, the need for an objective way to assess student performance has quickly increased in the Italian educational system. The competence evaluation can be carried out by analyzing the results of a questionnaire containing a set of items. In this work, we analyze the results of a test on mathematics literacy administered to pupils attending the last year of lower secondary school. In particular, we compare different methods in the latent variable model framework.

Manuale dedicato agli studenti del corso di laurea in Medicina e Chirurgia.L'intento è di dare una visione sintetica, semplice e chiara della moderna Diagnostica per Immagini soffermandosi sulle nuove metodiche di imaging utilizzate sia in campo diagnostico, sia in campo radioterapico.Il capitolo sulla radioterapia è incentrato sulla descrizione degli effetti delle radiazioni sia sui tumori che sui tessuti sani e sullo sviluppo delle nuove tecniche attualmente utilizzate a livello internazionale che hanno permesso, neglia anni, di rendere molto più precisi e personalizzati i trattamenti limitando così la tossicità.

Questo manuale è dedicato agli studenti del corso di Laurea di medicina e Chirurgia e nasce dall’esperienza didattica congiunta delle scuole radiologiche di Bologna, Modena e Parma. L’intento che ha ispirato gli autori non è quello di creare tanti piccolo radiologi e nemmeno quello di fornire il materiale minimo per superare l’esame, ma piuttosto di dare una visione, necessariamente sintetica, della moderna Diagnostica per Immagini, vista dalla prospettiva di coloro che saranno i futuri prescrittori di indagini radiologiche, intento che è stato perseguito soffermandosi in particolare sulla descrizione delle metodiche di imaging, sulle loro indicazione contro-indicazioni e sui flussi diagnostici integrati in relazione alle principali evenienze cliniche.

PREFAZIONE: Questo manuale è dedicato agli studenti del corso di Laurea di medicina e Chirurgia e nasce dall’esperienza didattica congiunta delle scuole radiologiche di Bologna, Modena e Parma. L’intento che ha ispirato gli autori non è quello di creare tanti piccolo radiologi e nemmeno quello di fornire il materiale minimo per superare l’esame, ma piuttosto di dare una visione, necessariamente sintetica, della moderna Diagnostica per Immagini, vista dalla prospettiva di coloro che saranno i futuri prescrittori di indagini radiologiche, intento che è stato perseguito soffermandosi in particolare sulla descrizione delle metodiche di imaging, sulle loro indicazione contro-indicazioni e sui flussi diagnostici integrati in relazione alle principali evenienze cliniche.

PREFAZIONE: Questo manuale è dedicato agli studenti del corso di Laurea di medicina e Chirurgia e nasce dall’esperienza didattica congiunta delle scuole radiologiche di Bologna, Modena e Parma. L’intento che ha ispirato gli autori non è quello di creare tanti piccolo radiologi e nemmeno quello di fornire il materiale minimo per superare l’esame, ma piuttosto di dare una visione, necessariamente sintetica, della moderna Diagnostica per Immagini, vista dalla prospettiva di coloro che saranno i futuri prescrittori di indagini radiologiche, intento che è stato perseguito soffermandosi in particolare sulla descrizione delle metodiche di imaging, sulle loro indicazione contro-indicazioni e sui flussi diagnostici integrati in relazione alle principali evenienze cliniche.

PREFAZIONE: Questo manuale è dedicato agli studenti del corso di Laurea di medicina e Chirurgia e nasce dall’esperienza didattica congiunta delle scuole radiologiche di Bologna, Modena e Parma. L’intento che ha ispirato gli autori non è quello di creare tanti piccolo radiologi e nemmeno quello di fornire il materiale minimo per superare l’esame, ma piuttosto di dare una visione, necessariamente sintetica, della moderna Diagnostica per Immagini, vista dalla prospettiva di coloro che saranno i futuri prescrittori di indagini radiologiche, intento che è stato perseguito soffermandosi in particolare sulla descrizione delle metodiche di imaging, sulle loro indicazione contro-indicazioni e sui flussi diagnostici integrati in relazione alle principali evenienze cliniche.

PREFAZIONE: Questo manuale è dedicato agli studenti del corso di Laurea di medicina e Chirurgia e nasce dall’esperienza didattica congiunta delle scuole radiologiche di Bologna, Modena e Parma. L’intento che ha ispirato gli autori non è quello di creare tanti piccolo radiologi e nemmeno quello di fornire il materiale minimo per superare l’esame, ma piuttosto di dare una visione, necessariamente sintetica, della moderna Diagnostica per Immagini, vista dalla prospettiva di coloro che saranno i futuri prescrittori di indagini radiologiche, intento che è stato perseguito soffermandosi in particolare sulla descrizione delle metodiche di imaging, sulle loro indicazione contro-indicazioni e sui flussi diagnostici integrati in relazione alle principali evenienze cliniche.

PREFAZIONE: Questo manuale è dedicato agli studenti del corso di Laurea di medicina e Chirurgia e nasce dall’esperienza didattica congiunta delle scuole radiologiche di Bologna, Modena e Parma. L’intento che ha ispirato gli autori non è quello di creare tanti piccolo radiologi e nemmeno quello di fornire il materiale minimo per superare l’esame, ma piuttosto di dare una visione, necessariamente sintetica, della moderna Diagnostica per Immagini, vista dalla prospettiva di coloro che saranno i futuri prescrittori di indagini radiologiche, intento che è stato perseguito soffermandosi in particolare sulla descrizione delle metodiche di imaging, sulle loro indicazione contro-indicazioni e sui flussi diagnostici integrati in relazione alle principali evenienze cliniche.

In this work, the theme of student guidance in the university context is outlined. In order to introduce the competence evaluation for student guidance, a new guidance project based on self-evaluation tests of the University of Bologna (Italy) is presented. In the paper, the issues of item specification and test calibration are explored, with reference to item response theory models. Models are for multiple-choice and binary items and they assume that a single ability is responsible for the student performance in the test. The test calibration is conducted for the Statistics Faculty and the results are discussed, together with the future developments of the project.