74 research outputs found

    R&D, firm size, and product innovation dynamics.

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    This paper addresses a debated issue in the economics innovation literature, namely the existence of increasing return to R&D expenditures and firm size on innovation output. It further explores how structural characteristics of the firm as well as contextual factors affect the dynamics of product innovation over a relatively long period of time. Taking advantage of an original and unique database comprising innovation data recorded on a monthly base we show that: (i) a negative binomial distribution model is able to predict with great accuracy the probability of having a given number of product announcement sent out in a month; (ii) constant returns to size and R&D expenditure may reasonably characterize the innovation production function of sampled firms; (iii) vertically integrated manufacturers as well as producers operating a larger product portfolio exhibit a higher propensity to introduce new products than their specialized competitors.

    R&D, Firm Size, and Product Innovation Dynamics.

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    This paper addresses a debated issue in the economics innovation literature, namely the existence of increasing return to R&D expenditures and sirm size on innovation output. It further explores how structural characteristics of the sirm as well as contextual factors affect the dynamics of product innovation over a relatively long period of time. Taking advantage of an original and unique database comprising innovation data recorded on a monthly base we show that: (i) a negative binomial distribution model is able to predict with great accuracy the probability of having a given number of product announcement sent out in a month; (ii) constant returns to size and R&D expenditure may reasonably characterize the innovation production function of sampled sirms; (iii) vertically integrated manufacturers as well as producers operating a larger product portfolio exhibit a higher propensity to introduce new products than their specialized competitors.

    An R package for fitting age, period and cohort models

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    In this paper we present the R implementation of a GLIM macro which fits age-period-cohort model following Osmond and Gardner. In addition to the estimates of the corresponding model, owing to the programming capability of R as an object oriented language, methods for printing, plotting and summarizing the results are provided. Furthermore, the researcher has fully access to the output of the main function (apc) which returns all the models fitted within the function. It is so possible to critically evaluate the goodness of fit of the resulting mode

    Role of Body Weight in the Onset and the Progression of Idiopathic Premature Pubarche

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    Background: The term premature pubarche (PP) refers to the appearance of pubic hair before age 8 in girls and before age 9 in boys. Although idiopathic PP (often associated with premature adrenarche) is considered an extreme variation from the norm, it may be an initial sign of persistent hyperandrogenism. Factors contributing to PP onset and progression have not been identified to date. Aims: The objectives of this study are to describe a group of Italian children with PP, to identify potential factors for its onset, and to define its clinical and biochemical progression. Methods: We retrospectively enrolled all infants born between 2001 and 2014 with PP. Children with advanced bone age (BA) underwent functional tests to determine the cause of PP. Hormonal analysis and BA determination were performed annually during a 4-year follow-up period. Results: A total of 334 children with PP were identified: idiopathic PP (92.5%, associated with premature adrenarche in some cases); related to precocious puberty (6.6%); late-onset 21-hydroxylase deficiency (0.9%). Low birth weight was associated with premature adrenal activation. Body mass index (BMI) was the only factor that influenced the progression of BA during follow-up. Conclusions: Low birth weight is a predisposing factor for premature adrenal activation. The increase in BMI in patients with idiopathic PP during the 4-years of follow-up was responsible for BA acceleration. We recommend prevention of excessive weight gain in children with PP and strict adherence to follow-up in order to prevent serious metabolic consequences

    Integrating MOOCs in physics preliminary undergraduate education: beyond large size lectures

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    In this paper, the authors discuss the effectiveness of MOOCs as part of a pedagogical strategy aimed at supporting Physics’ preliminary undergraduate students in large-size lectures. Our study is based on an experimental activity based on a blended course, which integrated a parallel MOOC delivered through the POK (PoliMi Open Knowledge, http://www.pok.polimi.it), the Politecnico di Milano’s MOOC portal. The blended model also delivered face-to-face activities that included intensive technology enhanced learning, like feedback based on clickers. Specifically, we introduce the several elements of the approach (the tutors’ pedagogy, the adoption of clickers, the diversity amongst learning groups) and its process of implementation. The findings in this study highlight that the integrated model is effective in terms’ of students’ learning both for small and large size lectures. More importantly, it was found that the students in large size lectures demonstrated similar or even better performance than students in a small size group. Moreover, the students in all sizes lectures showed higher satisfaction with the MOOCs’ against other factors adopted within the learning design

    R&D, firm size, and product innovation dynamics

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    This paper addresses a debated issue in the economics innovation literature, namely the existence of increasing return to R&D expenditures and firm size on innovation output. It further explores how structural characteristics of the firm as well as contextual factors affect the dynamics of product innovation over a relatively long period of time. Taking advantage of an original and unique database comprising innovation data recorded on a monthly base we show that: (i) a negative binomial distribution model is able to predict with great accuracy the probability of having a given number of product announcement sent out in a month; (ii) constant returns to size and R&D expenditure may reasonably characterize the innovation production function of sampled firms; (iii) vertically integrated manufacturers as well as producers operating a larger product portfolio exhibit a higher propensity to introduce new products than their specialized competitors

    Clustering of Hemodynamic and Metabolic Abnormalities and of Anthropometric Characteristics in Men and Women, Aged 21—60 Years

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    The associations between fat pattern and metabolic profile were evaluated , using cluster analysis, in 214 males and 244 fem ales (aged 21-60 years). The subjects were randomly selected from the patients of one general practice in Castel D’Azzano (Italy). The metabolic status was indexed by blood pressure, blood glucose, uric acid , serum triglycerides, total cholesterol, low-density lipo protein cholesterol, and high-density lipo protein cholesterol (both total and percentage). Fat pattern was evaluated using six skinfolds and three circumferences. The analyses were performed separately on anthropometric and metabolic variables for each sex. The analyses were repeated five times to evaluate the stability of the cluster solution . Anthropometric rather than metabolic variables provided a more stable solution for cluster analysis. Anthropometric clusters showed significantly different metabolic patterns. Most of the differences disappeared when a body mass index (BMI) effect was taken into account but not when an adjustment for waist to hip ratio (WHR) was made. On the other hand, neither BMI nor WHR was able to fully account for the differences in metabolic profiles of metabolic clusters. Cross-classification results of anthropometric and metabolic cluster mem bership showed a significant, although moderate, degree of association between the two classification sets. These results indicate that in both sexes an thropometric characteristics contribute to a limited degree to the metabolic profile and that the associations probably reflect a complex mechanism

    Cross-modal associations between materic painting and classical Spanish music

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    The study analyses the existence of cross-modal associations in the general population between a series of paintings and a series of clips of classical (guitar) music. Because of the complexity of the stimuli, the study differs from previous analyses conducted on the association between visual and acoustic stimuli, which predominantly analysed single tones and colours by means of psychophysical methods and forced choice responses. More recently, the relation between music and shape has been analyzed in terms of music visualization, or relatively to the role played by emotion in the association, and free response paradigms have also been accepted. In our study, in order to investigate what attributes may be responsible for the phenomenon of the association between visual and acoustic stimuli, the clip/painting association was tested in two experiments: the first used the semantic differential on a unidimensional rating scale of adjectives; the second employed a specific methodology based on subjective perceptual judgments in first person account. Because of the complexity of the stimuli, it was decided to have the maximum possible uniformity of style, composition and musical colour. The results show that multisensory features expressed by adjectives such as ‘quick’, ‘agitated’, and ‘strong’, and their antonyms ‘slow’, ‘calm’, and ‘weak’ characterized both the visual and acoustic stimuli, and that they may have had a role in the associations. The results also suggest that the main perceptual features responsible for the clip/painting associations were hue, lightness, timbre, and musical tempo. Contrary to what was expected, the musical mode usually related to feelings of happiness or to feelings of sadness and spatial orientation did not play a significant role in the association. The main result of the study consists in showing the existence of cross-modal associations between high complex stimuli
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