Stefano Noventa

An Analysis of Item Response Theory and Rasch Models Based on the Most Probable Distribution Method

The most probable distribution method is applied to derive the logistic model as the distribution accounting for the maximum number of possible outcomes in a dichotomous test while introducing latent traits and item characteristics as constraints to the system. The item response theory logistic models, with a particular focus on the one-parameter logistic model, or Rasch model, and their properties and assumptions, are discussed for both infinite and finite populations.

Explorative surgery for acute scrotal pain: The importance of patient age, side affected, time to surgery and surgeon

INTRODUCTION AND OBJECTIVE Testicular torsion must be diagnosed quickly and accurately. The delay of the diagnosis and the subsequent delay of surgery may lead to loss testicular viability and orchidectomy. Aim of our retrospective evaluation was to define which element should be considered as major support to the clinician in distinguishing spermatic cord torsion from the other diseases mimicking this clinical emergency requiring surgical exploration. MATERIAL AND METHODS We retrospectively reviewed all clinical and instrumental data of emergency scrotal exploration performed for acute scrotal pain at two different Urological Department in a 10 year period. Results of surgical exploration represented the four diagnostic categories in which patients were divided for statistical evaluation. We evaluated the relationship between diagnosis performed by testicular surgical exploration and the all clinical data available including surgeon involved in the procedures. RESULTS A total of 220 explorative scrotal surgery were considered. We divided the cases in 4 categories according to the diagnostic results of each surgical procedure. Of all, spermatic cord torsion was diagnosed in 45% (99/220). The total testis salvage rate was of 78.8%. The patients with a diagnosis of spermatic cord torsion were older than patients with appendix torsion (15 vs 11 years in mean). When the affected side was the left, the probability to have a diagnosis of spermatic cord torsion was higher than the right side [χ2 (2, N = 218) = 11.77, p < 0.01]. Time elapsing between onset of symptoms and testicular salvagewas significantly lower even than in case of appendix torsion/necrosis (p < .0001), and of others pathologies diagnosed (p = .0383). CONCLUSION In case of spermatic cord torsion, in addition to the clinical data, patient age and left side affected may represent an independent diagnostic predicting factor. The time elapsing between onset of symptoms and explorative surgery remain the only still prognostic factor for testicular viability.

Family Business and Entrepreneurship: Competencies and Organizational Behavior

Family-owned enterprises go through various stages of growth and development over time once the second and subsequent generations enter the business. They present a unique set of challenges and problems, mostly due to generational transition, role confusion, different vision of the business, qualification and skills. This quantitative study aims at increasing the understanding of which competencies are relevant to family business success and how they significantly influence both organizational behavior and family dynamics. Findings highlight the importance of family business as a unique context to study organizational behavior and confirmed how family enterprises are influenced by family culture and kinship ties.

Modeling the overalternating bias with an asymmetric entropy measure.

Psychological research has found that human perception of randomness is biased. In particular, people consistently show the overalternating bias: they rate binary sequences of symbols (such as Heads and Tails in coin flipping) with an excess of alternation as more random than prescribed by the normative criteria of Shannons entropy. Within data mining for medical applications, Marcellin proposed an asymmetric measure of entropy that can be ideal to account for such bias and to quantify subjective randomness. We fitted Marcellins entropy and Renyis entropy (a generalized form of uncertainty measure comprising many different kinds of entropies) to experimental data found in the literature with the Differential Evolution algorithm. We observed a better fit for Marcellins entropy compared to Renyis entropy. The fitted asymmetric entropy measure also showed good predictive properties when applied to different datasets of randomness-related tasks. We concluded that Marcellins entropy can be a parsimonious and effective measure of subjective randomness that can be useful in psychological research about randomness perception.

Assessing the Relation between Entrepreneurial Environment and Institutions and Aptitude towards Entrepreneurship: an Experience in Veneto’s Vocational Schools

Satisfaction of those needs which are fundamental to life-quality often depends on availability of opportunities related to human and social capital, which in their turn are favoured by education. As in financial and social crises young people with low qualifications are one of the weakest segments in the labour market as they are exposed to work exclusion, long-term scar effects, and vulnerable market position, public institutions must reinforce policies and practices to foster school-to-work transition. European Union indeed advocates the enhancement of entrepreneurial education related policies and practices. As entrepreneurship is however strongly interlinked with formal and informal institutions, socio-cultural and economic contexts, a similar interplay exists between regional context, enterprise education and vocational training. The present work explores characteristics and aptitude towards entrepreneurship possessed by students of vocational education and training centres in the Italian Veneto region as a case study to explore the degree to which low qualified young students, in contact with an entrepreneurial formal or informal environment, show higher level of knowledge, propensity, self-efficacy and aptitude towards entrepreneurship. Some implications for entrepreneurial education and policies are provided.

A derivation of the polytomous rasch model based on the most probable distribution method

Boltzmanns most probable distribution method is applied to derive the Polytomous Rasch model as the distribution accounting for the maximum number of possible outcomes in a test while introducing latent traits, item characteristics, and thresholds as constraints to the system. Affinities and similarities of the present result with other derivations of the model are discussed in light of the conceptual frameworks of statistical physics and of the principle of maximum entropy.

Work values and aging workforce. a perspective on value orientations and motivations for post-retirement activities

Population ageing is not only linked to social or health problems, but it also concerns economic and HRM strategies and policies in work organizations. Elderly and retired workers are often still active and recent literature in social sciences has indeed focused on the management and motivation of ageing workforce. The present work aims to explore the relationships between reasons to stay active and the work values of elderly workers, by examining how value orientations affect the reasons behind post-retirement activity. A questionnaire was administered to a sample of 480 north-Italian elderly, retired from different jobs who continued to work. Part of questionnaire adopted the Work Important Study/Work Values Scale (WIS/SVP) to explore the work values of aging workforce. As a result, people in retirement appear to be moved mainly by reasons of social connections and usefulness. More personal dimensions related to the need of being appreciated, self-realized, or the need of keep themselves active and busy are considered less important. Interestingly, financial reasons and work continuity are considered not important. In addition, work values and value orientations influence to various degrees these motivations to stay in activity after formal retirement. These findings suggest that HRM practices and policies, capable of motivating older workers to continue to work, should address social and relational issues rather than financial related aspects or continuous career development.