2,656 research outputs found
What drives the growth of start-up firms? A tool for mapping the state-of-the-art of the empirical literature
Purpose – This study aims to enrich the current theoretical debate on the growth of start-up firms by extensively investigating the ongoing empirical studies in this research stream. Moreover, this study identifies drivers whose support roles are confirmed in the literature and recommends further research opportunities. Design/methodology/approach – In this study, we analysed the results of 316 empirical studies on start-up firms and growth and also identified and categorised 66 growth drivers. We presented these drivers in three- dimensional charts: 1) the frequency of using each driver in the 316 studies, 2) the consistency of each driver as measured by the number of studies supporting its statistical significance and 3) the net effect (positive or negative) of each driver on growth.
Findings – Our analysis compares extant studies on growth drivers and shows some under-explored growth factors of start-up firms.
Practical implications – Both start-up managers and policymakers can benefit from this study. This study provided managers with a fine-grained tool on the main growth drivers and can guide policymakers in supporting policies for start-up firms.
Originality/value – This study provides a rich, fine-grained and coherent picture of several potential growth drivers of start-up firms. Moreover, we extended our analysis to various potential drivers more than previous studies on this topic, thereby providing fruitful insights into the critical growth factors for start-up firms
Creating and evaluating embodied interactive experiences: case studies of full-body, sonic and tactile enaction.
This thesis contributes to the field of embodied and multimodal interaction by presenting the development of different original interactive systems. Using a constructive approach, a variety of real-time user interaction situations were designed and tested, two cases of human-virtual character bodily interaction, two interactive sonifications of trampoline jumping, collaborative interaction in mobile music performance and tangible and tactile interaction with virtual sounds.
While diverse in terms of application, all the explored interaction techniques belong to the context of augmentation and are grounded in the theory of embodiment and strategies for natural human-computer interaction (HCI). The cases have been contextualized within the umbrella of enaction, a paradigm of cognitive science that addresses the user as an embodied agent situated in an environment and coupled to it through sensorimotor activity. This activity of sensing and action is studied through different modalities: auditory, tactile and visual and combinations of these. The designed applications aim at a natural interaction with the system, being full-body, tangible and spatially aware. Particularly sonic interaction has been explored in the context of music creation, sports and auditory display. These technology-mediated scenarios are evaluated in order to understand what the adopted interaction techniques can bring to the user experience, how they modify impressions and enjoyment. The publications also discuss the enabling technologies used for the development, including motion tracking and programmed hardware for the tactile-sonic interaction and sonic and tangible interaction.
Results show that combining full-body interaction with auditory augmentation and sonic interaction can modify the perception, observed behavior and emotion during the experience. Using spatial interaction together with tangible interaction or tactile feedback provides for a multimodal experience of exploring a mixed reality environment where audio can be accessed and manipulated with natural interaction. Embodied and spatial interaction brings playfulness to a mobile music improvisation, shifting the focus of the experience from music-making towards movement-based gaming. Finally, two novel implementations of full-body interaction based on the enactive paradigm are presented. In these designed scenarios of enaction the participant is motion tracked and a virtual character rendered as a stick figure is displayed in front of her on a screen. Results from the user studies show how the involvement of the body is crucial in understanding the behavior of a virtual character or a digital representation of the self in a gaming scenario
Qualidade fĂsica do solo sob floresta secundária, leguminosas arbĂłreas e pastagem degradada
The objective of this work was to assess the efficiency of revegetation with forest leguminous species, for the recovery of the physical quality of a Typic Hapludult under degraded pasture, located in a steep-slope tropical landscape in Southeastern Brazil. Soil samples were collected at the 0–0.10 m and 0.10–0.20 m depths, in areas under Acacia auriculiformis (northern black wattle), Mimosa caesalpiniifolia (“sabiá”), Inga edulis (“ingá”), secondary forest (“capoeira”), and degraded pasture. Tensile strength (TS) was evaluated in soil aggregates of the size classes 8.0–12.5 mm and 12.5–19.0 mm, for the variables TS 8 and TS 12.5, respectively. The lowest mean values of both variables always occurred under the pasture cover (TS 8 of 37.1 kPa and TS 12.5 of 22.7 kPa, for the 0–0.10 m soil layer; and TS 8 of 39.2 kPa and TS 12.5 of 22.8 kPa, for the 0.10–0.20 m soil layer). The highest TS mean values were obtained under the “capoeira” cover (TS 8 of 62.2 kPa, for the 0–0.10 m soil layer) and “sabiá” cover (TS 12.5 of 46.0 kPa, for the 0–0.10 m soil layer; and TS 8 of 53.0 kPa and TS 12.5 of 51.4 kPa, for the 0.10–0.20 m soil layer). Land revegetation with leguminous trees recovers the soil physical quality, since the TS values under the evaluated covers are predominantly closer to those of the secondary forest than to those of the degraded pasture.O objetivo deste trabalho foi avaliar a eficiĂŞncia da revegetação com espĂ©cies leguminosas florestais, para a recuperação da qualidade fĂsica de um Argissolo Vermelho-Amarelo sob pastagem degradada, localizado em uma paisagem tropical de declive acentuado no Sudeste brasileiro. Amostras de solo foram coletadas nas profundidades de 0–0,10 e 0,10–0,20 m em áreas sob Acacia auriculiformis (acácia), Mimosa caesalpiniifolia (sabiá), Inga edulis (ingá), floresta secundária (capoeira) e pastagem degradada. A resistĂŞncia tĂŞnsil (TS) foi avaliada em agregados das classes de tamanhos de 8,0–12,5 e de 12,5–19,0 mm para as variáveis TS 8 e TS 12.5, respectivamente. Os menores valores mĂ©dios dessas duas variáveis ocorreram sempre sob pastagem (TS 8 de 37,1 kPa e TS 12.5 de 22,7 kPa, para a camada de 0–0,10 m; e TS 8 de 39,2 kPa e TS 12.5 de 22,8 kPa, para a camada de 0,10–0,20 m). As maiores mĂ©dias foram obtidas sob capoeira (TS 8 de 62,2 kPa, para a camada de 0–0,10 m) e sabiá (TS 12.5 de 46,0 kPa, para a camada de 0–0,10 m; e TS 8 de 53,0 kPa e TS 12.5 de 51,4 kPa, para a camada de 0,10–0,20 m). A revegetação de terras com leguminosas arbĂłreas recupera a qualidade fĂsica do solo, uma vez que os valores de TS sob essas coberturas apresentam-se predominantemente mais prĂłximos dos TS da floresta secundária do que dos da pastagem degradada
Modelling the West Nile virus force of infection in the European human population
West Nile virus (WNV) is among the most recent emerging mosquito-borne pathogens in Europe where each year hundreds of human cases are recorded. We developed a relatively simple technique to model the WNV force of infection (FOI) in the human population to assess its dependence on environmental and human demographic factors. To this aim, we collated WNV human case-based data reported to the European Surveillance System from 15 European Countries during the period 2010–2021. We modelled the regional WNV FOI for each year through normal distributions and calibrated the constituent parameters, namely average (peak timing), variance and overall intensity, to observed cases. Finally, we investigated through regression models how these parameters are associated to a set of climatic, environmental and human demographic covariates. Our modelling approach shows good agreement between expected and observed epidemiological curves. We found that FOI magnitude is positively associated with spring temperature and larger in more anthropogenic semi-natural areas, while FOI peak timing is negatively related to summer temperature. Unsurprisingly, FOI is estimated to be greater in regions with a larger fraction of elderly people, who are more likely to contract severe infections. Our results confirm that temperature plays a key role in shaping WNV transmission in Europe and provide some interesting hints on how human presence and demography might affect WNV burden. This simple yet reliable approach could be easily adopted for early warning and to address epidemiological investigations of other vector-borne diseases, especially where eco-epidemiological data are scarc
Enhanced and Flexible Software Tools for X-ray Computed Tomography at the Italian Synchrotron Radiation Facility Elettra
X-ray computed tomography (CT) experiments performed at synchrotron radiation facilities require adequate computing and storage resources due to the large amount of acquired and reconstructed data produced. To satisfy the heterogeneous needs of beamline users, flexible solutions are also required. Moreover, the growing demand of quantitative image analysis impose an easy integration between the CT reconstruction process and the subsequent feature extraction step. This paper presents some of the software solutions adopted by the SYRMEP beamline of the Italian synchrotron radiation facility Elettra. By using the enhanced version of the reconstruction software here presented as well as data reduction and data analysis tools, beamline users can easily implement an integrated and comprehensive approach to the digital image processing and image analysis required by a tomography-oriented scientific workflow
Cardio-Metabolic Indices and Metabolic Syndrome as Predictors of Clinical Severity of Gastroenteropancreatic Neuroendocrine Tumors
BackgroundObesity, mainly visceral obesity, and metabolic syndrome (MetS) are major risk factors for the development of type 2 diabetes, cardiovascular diseases, and cancer. Data analyzing the association of obesity and MetS with gastroenteropancreatic neuroendocrine neoplasms (GEP-NEN) are lacking. Fatty liver index (FLI) is a non-invasive tool for identifying individuals with non-alcoholic fatty liver disease (NAFLD). Visceral adiposity index (VAI) has been suggested as a gender-specific indicator of adipose dysfunction. Both indexes have been proposed as early predictors of MetS. This study aimed to investigate the association of FLI VAI as early predictors of MetS with gastroenteropancreatic neuroendocrine tumors (GEP-NETs).MethodsA cross-sectional, case-control, observational study was carried out at the ENETS Centers of Excellence Multidisciplinary Group for Neuroendocrine Tumors, University "Federico II". VAI and FLI were calculated.ResultsWe enrolled 109 patients with histologically confirmed G1/G2 GEP-NET (53 M; 57.06 +/- 15.96 years), as well as 109 healthy subjects, age, sex- and body mass index-matched. Forty-four GEP-NET patients were G2, of which 21 were with progressive disease, and 27 patients had metastases. GEP-NET patients had a higher value of VAI (p < 0.001) and FLI (p = 0.049) and higher MetS presence (p < 0.001) compared with controls. VAI and FLI values and MetS presence were higher in G2 than in G1 patients (p < 0.001), in patients with progressive disease, and in metastatic vs non-metastatic patients (p < 0.001). In addition, higher values of VAI and FLI and higher MetS presence were significantly correlated with the worst clinical severity of NENs. The cut-off values for the FLI and MetS to predict high grading of GEP-NETs and the presence of metastasis were also provided.ConclusionsThis is the first study investigating an association between VAI and FLI as early predictors of MetS and GEP-NET. Our findings report that the worsening of clinicopathological characteristics in GEP-NET is associated with higher presence of MetS, NAFLD, evaluated by FLI, and visceral adiposity dysfunction, evaluated by VAI. Addressing the clinical evaluation of MetS presence, NAFLD, and visceral adiposity dysfunction might be of crucial relevance to establish targeted preventive and treatment interventions of NEN-related metabolic comorbidities
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