1,720,987 research outputs found
Noncentral moderate deviations for time-changed Lévy processes with inverse of stable subordinators
Full text linkThis paper presents some extensions of recent noncentral moderate deviation results.
In the first part, the results in [Statist. Probab. Lett. 185, Paper No. 109424, 8 pp. (2022)]
are generalized by considering a general Lévy process {S(t) : t ≥ 0} instead of a compound
Poisson process. In the second part, it is assumed that {S(t) : t ≥ 0} has bounded variation
and is not a subordinator; thus {S(t) : t ≥ 0} can be seen as the difference of two independent
nonnull subordinators. In this way, the results in [Mod. Stoch. Theory Appl. 11, 43–61] for
Skellam processes are generalized
Some Results on Generalized Accelerated Motions Driven by the Telegraph Process
No full textWe investigate a generalization of the randomly accelerated motion obtained by iterated integration of the telegraph signal. We give the exact and explicit expression for the cumulative distribution function, conditionally on the number n of Poisson events, when n is sufficiently small. The unconditional mean value and variance are also obtained
Financing A Free-for-All: Crowdfunding Open-Source Software
Full text linkThis paper examines whether open-source software (OSS) provides unique advantages in the entrepreneurial crowdfunding context. The economic model for new ventures with business plans cen- tered on OSS is often counterintuitive to early-stage investors. On the one hand, the non-restrictive OSS approach reduces the barriers to widespread product adoption and collaboration; on the other, OSS is essen- tially a public good, creating a scenario where anyone can appropriate value from the product without com- pensating its creators. As such, an OSS approach can dissuade investors primarily concerned with appro- priating value for themselves, making it difficult for early-stage OSS ventures to attract investors. However, the rapid rise of crowdfunding has created a com- munally minded investor base that might instead find OSS projects enticing. We theorize that the attributes of OSS projects align with the communal expectations of crowdfunding investors and thus create supportive environments for OSS-based ventures. We illustrate this alignment through the community-based resource mobilization framework and suggest that the OSS approach yields greater investor trust, leading to supe- rior financing outcomes. Our mixed methods approach blends archival analyses of Kickstarter data with a con- structive replication through a randomized experiment, providing consistent support that an OSS approach can be advantageous in the crowdfunding context
The effectiveness of university regulations to foster science-based entrepreneurship
Full text linkIn this study, we analyze the effect of the introduction of university regulations supporting academic entrepreneurship. Using a sample of 611 companies spun-off from the 64 Italian Science, Technology, Engineering, Mathematics and Medicine (STEMM) universities between 2002 and 2012, we show that university regulations in support of academic entrepreneurship have a positive effect on the creation of academic spin-offs. Nevertheless, their effectiveness is conditioned by specific contingencies. First, the characteristics of university departments influence the positive effect of the regulation: in some cases, there is a substitution effect rather than a complementary one. Second, the design of the regulation impacts the decisions of academic staff regarding whether to start a new venture. Finally, the effect of the regulation is maximized four years after its introduction and then becomes less effective. This paper contributes to the debate on the evaluation of policies supporting science-based entrepreneurship
The Fractional Birth Process with Power-Law Immigration
No full textA semi-stochastic description of the mutation process with memory effects in a power-law growing cell colony is considered. Specifically, we give explicit expressions for the distribution of the number of mutants in a single clone, and of the total number of mutants. The investigation is performed under the assumption that clones grow according to a fractional linear birth process, characterized by a non-exponential, Mittag-Leffler waiting time distribution. Its slowly decaying long tail enables modeling bursty dynamics: very dense sequences of events are separated by long times of reduced activity. The probabilistic construction also allows for recovering the mean and the variance of the total number of mutants. We then give exact formulas for the higher-order moments of the fractional linear birth process and of the clone size, thus providing additional insight into this evolutionary process
Gender and innovation strategy in crowdfunding
Full text linkIn this chapter first, we review the recent literature concerning female crowdfunding entrepreneurs (e.g., creators) and contrast those findings to those found in traditional entrepreneurial finance. Next, we examine the nature of innovations in crowdfunding and how these innovations are perceived by crowdfunding investors (e.g., backers). We then build our core proposition, which is then supported by our large sample of crowdfunding data. Last, we outline an agenda for future empirical research and conclude with a discussion on the practical application of this work, highlighting the opportunities that lie ahead for female founders pursuing innovative new ventures
Non-tuberculous mycobacterial diseases in children
Full text linkNon-tuberculous mycobacteria (NTMs) are ubiquitous and opportunistic emerging bacteria with the potential to colonize and eventually infect either immunocompromised or immunocompetent individuals. In the last three decades, the prevalence of disease caused by NTMs has increased in several countries. The increased prevalence of NTM infection can be explained by an ageing population with rising comorbidities, HIV infection, the common use of immunosuppressive drugs, and improved diagnostic methods. The aim of this review is to demonstrate the clinical relevance of NTMs in children, describing their features and manifestations, diagnostic tools, and therapeutic approaches. We collected data from the literature about NTM infections in young patients over the past five years (2014–2019) using the keywords “non-tuberculous”, “mycobacteria”, “paediatric”, “NTM”, “cystic fibrosis”, and “children”. Recent literature points out that NTMs are ubiquitous, with several species including both those that are pathogens for humans and those that are not. This means that, if a mycobacterium is isolated from a patient’s specimen, we have to distinguish between a simple colonization and an NTM-related disease. The start of treatment depends on many factors that are necessary to consider, such as clinical and imaging features, patient comorbidity and immunocompetence, drug adverse effects, and compliance with a very long therapy that can last many months. Due to the increasing prevalence and clinical relevance of NTMs, guidelines for their optimal management, especially in the presence of chronic underlying disease, are urgently needed
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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