2,357 research outputs found

    Statistical Analysis of V85 Models on Horizontal Curves of Italian Two-Lane Rural Roads

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    Injuries are one of the main causes of death according to the new report published by WHO (World Health Organization). For this reason the attention of road safety research especially regards the study of the relationship between driver and road environment, in order to obtain a reduction of injuries number and severity. Several studies were developed to find the relationships between road geometrical and design features and driver behaviour. Generally driver behaviour is expressed by the operating speed. In scientific literature there exist several analytical models to calculate real speed as a function of geometrical road characteristics. In this work some of them were collected and their hypotheses were studied. Generally the values of these parameters were similar in the majority of the models and they can be found in the Italian rural roads in order to make surveys. The next step was the statistical analysis of the existing models with hypotheses that could be applied to Italian roads in order to define the best one

    Funding sources, colonial legacy, and new firms’ creation in Africa

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    This study examines the determinants of new firm creation in Africa, focusing on external and internal funding sources and their interactions. It also explores the influence of colonial history by separately analyzing former British and French colonies. The primary goal is to help fill crucial gaps in African literature on the determinants of entrepreneurship. Given Africa's widespread poverty and underdevelopment, understanding what drives entrepreneurship is essential for job creation and economic growth. The study reveals three key findings. First, at the full sample level, remittances are the only external financing source positively associated with new firm creation, while foreign aid and foreign direct investment obstacle it. Internal sources, like savings and credit, do not show significant effects. Second, the subsample analysis reveals heterogeneous results: former British colonies' funding sources align with the overall findings, while in former French colonies, only savings support entrepreneurship. Third, considering control variables, the subsample analysis indicates two distinct entrepreneurship models: opportunity-based in former British colonies and necessity-based in former French colonies. These findings are noteworthy and provide significant policy implications at both national and international levels. Crucially, the positive role of remittances in financing new business initiatives, confirms that migration serves as a mutually beneficial arrangement for both sending African countries and the host countries

    Relationship between blood remifentanil concentration and stress hormone levels during pneumoperitoneum in patients undergoing laparoscopic cholecystectomy

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    The effect of remifentanil on stress response to surgery is unclear. However, there are not clinical studies investigating the relationship between blood remifentanil concentrations and stress hormones. Therefore, the aim of the present study was to assess the association between blood remifentanil concentrations measured after pneumoperitoneum and cortisol (CORT) or prolactin (PRL) ratio (intraoperative/preoperative value), in patients undergoing laparoscopic cholecystectom

    Brain connectivity changes after osteopathic manipulative treatment: A randomized manual placebo-controlled trial

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    The effects of osteopathic manipulative treatment (OMT) on functional brain connectivity in healthy adults is missing in the literature. To make up for this lack, we applied advanced network analysis methods to analyze resting state functional magnetic resonance imaging (fMRI) data, after OMT and Placebo treatment (P) in 30 healthy asymptomatic young participants randomized into OMT and placebo groups (OMTg; Pg). fMRI brain activity measures, performed before (T0), immediately after (T1) and three days after (T2) OMT or P were used for inferring treatment effects on brain circuit functional organization. Repeated measures ANOVA and post-hoc analysis demonstrated that Right Precentral Gyrus (F (2, 32) = 5.995, p < 0.005) was more influential over the information flow immediately after the OMT, while decreased betweenness centrality in Left Caudate (F (2, 32) = 6.496, p < 0.005) was observable three days after. Clustering coefficient showed a distinct time-point and group effect. At T1, reduced neighborhood connectivity was observed after OMT in the Left Amygdala (L-Amyg) (F(2, 32) = 7.269, p < 0.005) and Left Middle Temporal Gyrus (F(2, 32) = 6.452, p < 0.005), whereas at T2 the L-Amyg and Vermis-III (F(2, 32) = 6.772, p < 0.005) increased functional interactions. Data demonstrated functional connectivity re-arrangement after OMT

    Enhancing precision in coastal dunes vegetation mapping: ultra-high resolution hierarchical classification at the individual plant level

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    The classification of ultra-high-resolution (UHR) imagery, characterized by spatial resolutions exceeding 10 cm, presents opportunities and challenges distinct from lower-resolution counterparts. Particularly, challenges are pronounced in some scenarios, such as mapping plant species in coastal environments, where similar vegetation responses and small plant sizes pose additional difficulties. The present work addressed such issues by developing a UHR vegetation cover classification model at the single plant level using data from uncrewed aerial systems (UASs) equipped with a multispectral optical sensor. The model was tested across the San Rossore Regional Park (Italy), where three pilot areas were defined as training-test-validation sites. The proposed solution consists of a hierarchical two-level-of-detail machine learning model based on object-based image analysis (OBIA) and random forest. This model considers spectral features and indices, elevation, and texture and can classify twelve plant species and two service classes (debris and sand) within the study areas. Train and test were carried out utilizing UAS flight data collected during two specific phenological periods and precise field data derived from in-situ vegetation surveys, which provided 937 herbaceous and shrub samples. The model performance was evaluated based on the error matrix and 50-fold stratified cross-validation method, obtaining an overall accuracy (OA) of 0.76 and a standard deviation of 0.08. Such assessment underscored the crucial role of texture information, in addition to radiometric and elevation. Finally, the model was tested against an unseen dataset, proving its transferability (OA equal to 0.62). Although the discussion highlights some aspects to be further improved and claims for future research, the first version of this hierarchical classification model demonstrated its potential for mapping and monitoring coastal sand dune ecosystems, providing data for understanding and, eventually, modeling ecological and biogeomorphological dynamics

    FIRST RESULTS ON THE PRESENCE AND THE MOLECULAR CHARACTERIZATION OF ANISAKID NEMATODES IN MARINE FISH CAUGHT OFF NORTHERN SARDINIA

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    Anisakidosis is a parasitic zoonosis caused by nematodes of the family Anisakidae, belonging to the genera Anisakis, Contracaecum and Pseudoterranova. Molecular studies have shown that Anisakis larvae comprise a number of sibling species, which have different genetic structures, hosts and geographical distribution. A great variety of fish species can harbour infectious third stage larvae of this nematode. The preliminary results of a study carried out to evaluate the occurrence of this parasite in commercial fish caught off northern Sardinia are herein reported. From October 2008 to November 2009, 599 specimens of 8 commercial fish species were examined for anisakid larvae through visual inspection of body cavity and peptic digestion of the muscle. Isolated Anisakis sp. larvae were observed at light microscope and identified as Type I or Type II (sensu Berland, 1961). Out of 599 fish examined, 239 (40%) were infected by 1187 anisakid larvae, belonging to the genera Anisakis (1169 Type I and 18 Type II) and Hysterothylacium (692). The molecular identification of Anisakis spp. was carried out on a subsample of 30% of Type I larvae and all Type II larvae. Specimens were firstly examined using a species-specific PCR, with primers designed for Anisakis pegreffii (APEF) and Anisakis physeteris (APHF), and ITS-2 of nuclear rDNA. The results were confirmed by the analysis of the ITS region of nuclear rDNA (ITS-1, 5.8S and ITS-2) using the restriction enzymes HinfI and HhaI in PCR-RFLP. Type I larvae examined were all identified as A. pegreffii, and Type II were all A. physeteris. This is the first contribution to the epidemiology and molecular characterization of Anisakis spp. in commercial fish caught off Sardinia

    Age-related cognitive decline and the olfactory identification deficit are associated to increased level of depression

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    Purpose: Previous studies reported a correlation between olfactory function and depression. However, in literature, no data are available for the correlation between depression and all other factors such as age, sex, olfactory, gustatory, and cognitive function in healthy subjects taken together. The aim of this study was to provide a systematic account regarding the association between those variables in a nonclinical population. Methods: Two hundred and seventy-three participants were recruited with an age range of 19–84 years. Olfactory, gustatory, cognitive function, and depression level were evaluated by means of the following tests: the Sniffin’ Sticks test, Taste Strips test, Montreal Cognitive Assessment (MoCA), and Beck Depression Inventory (BDI). Results: In our data, an age-related decrease in olfactory and gustatory function and a decline in cognitive functions such as attention, memory, and language were observed. Instead, no significant differences were observed for the depression level in relation to the different age ranges. However, our results indicated that the depression level could be associated to sex, odor identification impairment, and decreased attention and language. Conclusion: Sex, the odor identification impairment, and an age-related decrease in attention and language are associated with increased level of depression in healthy subjects. Our data can be useful and informative for health care workers, that is, to have adequate preventive strategies to be used whenever these conditions are detected and recognized
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