445 research outputs found
Closed-form sums for some perturbation series involving associated Laguerre polynomials
Infinite series sum_{n=1}^infty {(alpha/2)_n / (n n!)}_1F_1(-n, gamma, x^2),
where_1F_1(-n, gamma, x^2)={n!_(gamma)_n}L_n^(gamma-1)(x^2), appear in the
first-order perturbation correction for the wavefunction of the generalized
spiked harmonic oscillator Hamiltonian H = -d^2/dx^2 + B x^2 + A/x^2 +
lambda/x^alpha 0 0, A >= 0. It is proved that the
series is convergent for all x > 0 and 2 gamma > alpha, where gamma = 1 +
(1/2)sqrt(1+4A). Closed-form sums are presented for these series for the cases
alpha = 2, 4, and 6. A general formula for finding the sum for alpha/2 = 2 + m,
m = 0,1,2, ..., in terms of associated Laguerre polynomials, is also provided.Comment: 16 page
Short- and Long-Term Changes in Attention, Memory and Brain Activity Following Exercise, Motor Learning, and Expertise
How humans perceive, embody, and execute actions has been an area of intense study in cognitive neuroscience, and these investigations shed light on how we adaptively learn from and interact with an ever-changing world. All of the knowledge associated with action, including sensorimotor representations, the words we use to describe them, and the memories that store this information, are represented in distributed brain regions that comprise knowledge schemas. With repeated practice or training, one can acquire a highly specialized motor repertoire that fosters even more efficient and adaptable behaviour to achieve peak performance. Using behavioural, EEG and fMRI approaches, I will present a series of investigations that evaluate the impact of short-term exercise and long-term dance practice on the development of expert knowledge schemas. In Chapters 2 and 3, I will demonstrate that activating one domain in the schema (e.g., action processing) will prime other domains (e.g., verbal attention and working memory) to induce translational performance improvements. Subsequent chapters will reveal how familiarity with a specific genre of dance influences behavioural (Chapter 3) and neurophysiological signatures of action perception, how these motor representations are coded in sensorimotor association areas (Chapters 4), and how they change with repeated practice and performance (Chapter 5). How these findings contribute to our model of expert knowledge schemas will be discussed in Chapter 6. These findings bear efficacy for the therapeutic application of exercise and dance programs to alleviate motor, cognitive and neurophysiological impairments in several clinical populations, including people with Parkinsons disease
Consumption Taxation and Endogenous Growth in a Model with New Generations
This article studies the implications of consumption taxation on capital accumulation in a one-sector endogenous growth model with finite horizons. A tax on consumption, when tax revenues are lump-sum rebated to consumers, redistributes income between living generations and future, still unborn, generations, and therefore depresses aggregate consumption and raises saving, stimulating capital accumulation and economic growth. If however the resources from taxation are used for financing unproductive public spending, the effect of the consumption tax on the endogenous growth rate disappears as no intergenerational redistribution of income occurs. Finally, a consumption tax hike accompanied by a compensatory reduction of public debt increases long-run economic growth and reduces the consumption-output ratio. Our results on consumption taxation differ substantially from those obtained within the endogenous growth literature.This article studies the implications of consumption taxation on capital accumulation in a one-sector endogenous growth model with finite horizons. A tax on consumption, when tax revenues are lump-sum rebated to consumers, redistributes income between living generations and future, still unborn, generations, and therefore depresses aggregate consumption and raises saving, stimulating capital accumulation and economic growth. If however the resources from taxation are used for financing unproductive public spending, the effect of the consumption tax on the endogenous growth rate disappears as no intergenerational redistribution of income occurs. Finally, a consumption tax hike accompanied by a compensatory reduction of public debt increases long-run economic growth and reduces the consumption-output ratio. Our results on consumption taxation differ substantially from those obtained within the endogenous growth literature.Refereed Working Papers / of international relevanc
Stories of courage in a group of adults with Substance Use Disorder
The treatment for drug addiction is considered a difficult path for the most of patients. As matter of fact, individuals with Substance Use Disorder (SUD) experience numerous challenges before, during and after the treatment (e.g. tackling an unpredictable, uncertain and paradoxically negative future, tackling the anxiety and anticipatory fear of physical pain associated with abstinence; decide to go beyond self-justification and self-deception). Courage could be considered a positive and functional resource to help people with SUD to face challenges and difficulties related to treatment. In connection therewith, the aim of this study was to examine, using an embedded mix method analysis, the personal stories of courage of 80 individuals with SUD in order to identify the themes and types of courage used in their life. The analysis carried out showed that individuals with SUD reported more frequently stories of courage related to their SUD condition respect to other life situation. Moreover, the quantitative analysis showed that participants used more frequently psychological courage respect to moral and physical courage when these stories were referred to their SUD condition then other life situations
Trophic Interactions of Callinectes sapidus (Blue Crab) in Vendicari Nature Reserve (Central Mediterranean, Ionian Sea) and First Record of Penaeus aztecus (Brown Shrimp)
Invasive alien species pose severe threats to global biodiversity, ecosystem functions, and socio-economic values, particularly in coastal and marine ecosystems. This study aimed to investigate the trophic interactions between alien species and native fauna in a Mediterranean coastal ecosystem. Notably, our research focused on the presence and ecological roles of the invasive Atlantic blue crab (Callinectes sapidus) and the brown shrimp (Penaeus aztecus) within the Vendicari Nature Reserve (VNR), a protected area on the southeastern coast of Sicily, Italy. Field observations, specimen collection, and interviews with local fishermen were conducted to assess the presence, distribution, and feeding habits of these species. The results revealed significant temporal shifts in the diet of C. sapidus, with a clear decrease in predation on the alien Penaeus aztecus (first observed in the VNR) over the study months. The presence of C. sapidus in the fishing area around the reserve has been detected for many years, while P. aztecus appears to have recently colonized the area. Additionally, photographic evidence documented the predation of C. sapidus by Octopus vulgaris, highlighting a potential adaptive feeding behavior by the common octopus in response to the abundance of this invasive crab. The integration of scientific research, local ecological knowledge, and community participation is essential for mitigating the impacts of biological invasions and preserving the biodiversity and ecological integrity of natural ecosystems
Life Design for an Inclusive and Sustainable Future
Societies today are highly complex and often impacted by uncertainty, rapid change, globalization, and inequality, all of which have significant impact on the wellbeing of people. These changes make it more difficult not only for a great part of the population to live in the present, but also for succeeding generations to aspire to and imagine a possible future. Considering this, career guidance needs a change of pace that can only be associated with investments in inclusion and sustainability. In this chapter we provide a brief historical excursion through the social role that career guidance has played through the years, and then outline possible actions that career guidance professionals could take so as to embrace, sustain, and foster the creation of a better future for everyone and to contribute to the creation of inclusive and sustainable societies.
Adenoma of the Ceruminous Gland (Ceruminoma)
Tumor arising from the ceruminous glands of the external ear canal (EAC) are very rare and can present a diagnostic dilemma because of their varied clinical and histologic manifestations. To our knowledge, this is the first report to present a case of ceruminoma in pediatric age. We discuss the origin of these tumors and the importance of wide excision and of the immunohistochemistry for the diagnosis
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