132 research outputs found

    A new approach for transport network design and optimization

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    The solution of the transportation network optimization problem actually requires, in most cases, very intricate and powerful computer resources, so that it is not feasible to use classical algorithms. One promising way is to use stochastic search techniques. In this context, Genetic Algorithms (GAs) seem to be - among all the available methodologies- one of the most efficient methods able to approach transport network design and optimization. Particularly, this paper will focus the attention on the possibility of modelling and optimizing Public Bus Networks by means of GAs. In the proposed algorithm, the specific class of Cumulative GAs(CGAs) will be used for solving the first level of the network optimization problem, while a classical assignment model ,or alternatively a neural network approach ,will be adopted for the Fitness Function(FF) evaluation. CGAs will then be utilized in order to generate new populations of networks, which will be evaluated by means of a suitable software package. For each new solution some indicators will be calculated .A unique FF will be finally evaluated by means of a multicriteria method. Altough the research is still in a preliminary stage, the emerging first results concerning numerical cases show very good perspectives for this new approach. A test in real cases will also follow.

    A double dynamic fast algorithm to solve multi-vehicle Dial a Ride Problem

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    Abstract In this work a two level heuristic algorithm is described for a nearly real-time multi-vehicle many-to-many Dial-A-Ride Problem (DARP). This algorithm is ready to support a Demand Responsive Transportation System in which we face the problem of quickly evaluate a good-quality schedule for the vehicles and provide fast response to the users. The insertion heuristic is double dynamic nearly real-time and the objective function is to minimize the variance between the requested and scheduled time of pickup and delivery. In the first level, after a customer web-request, the heuristic returns an answer about the possibility to insert the request into the accepted reservations, and therefore in a vehicle schedule, or reject the request. In the second level, during the time elapsed between a request and the following, and after a reshuffling of the order of the incoming accepted requests, the same heuristic works for the whole set of accepted requests, trying to optimize the solution. We intensively tested the algorithm with a requests-generating software that has allowed us to show the competitive advantage of this web-based architecture

    A Flexible Transport Service for Passengers

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    AbstractThe realization of innovative passengers transport services requires more and more often a greater flexibility and inexpensiveness of the service. To answer this request in many cases the physical solution is to realize a demand responsive transportation system (DRTS). A DRTS require the planning of travel paths (routing) and customers pick-up and drop-off times (scheduling) according to received requests, respecting the limited capacity of the fleet and time constraints (hard time windows) for each network's node, and the service time of the system. By the modelling point of view a DRTS can be effectively represented with a Dial-a-ride problem (DaRP). A DaRP derives from the Pick-up and Delivery Problem with Time Windows (PDPTW) and may operate according to a static or to a dynamic mode. In the static setting, all customers’ requests are known beforehand and the DaRP returns the vehicles routing and the passengers pick up and drop off time scheduling. The static setting may be representative of a phase of reservation occurred the day before the execution of the service. But, if the reservation requests must be processed on-line, even during the booking process there may be a certain level ad dynamism. In fact, if the algorithm works online, it manages each and every incoming request separately, and accepts or refuses it immediately, without knowing anything about the following. The operative program is constantly updated after each received request without refusal to carry out previous accepted services. In the dynamic mode, customers’ requests arrive when the service is already running and, consequently, the solution may change whilst the vehicle is already travelling. In this mode it is necessary that the schedule is updated when each new request arrives and that this is done in a short time to ensure that the potential customer will not leave the system before a possible answer. In this work, we describe a flexible people transport system capable of managing incoming transport demand in dynamic mode, using a solution architecture based on a two-stage algorithm to solve Dial-a-Ride Problem instances. In the first stage, a constructive heuristic algorithm quickly provides a feasible solution to accept the incoming demand. The algorithm in the second stage try to improve the solution evaluated at the first stage by using the time between two consecutive transportation events. The algorithm, unlike most of the works in the literature, use an objective function that optimizes the service punctuality

    Benefits of dietary supplements on the physical fitness of German Shepherd dogs during a drug detection training course

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    A high standard of physical fitness is an essential characteristic of drug detection dogs because it affects not only their ability to sustain high activity levels but also their attention and olfaction efficiency. Nutritional supplements could improve physical fitness by modulating energy metabolism, oxidative processes, and perceived fatigue. The aim of this study was to investigate the physiological and biochemical changes induced by submaximal exercise on drug detection dogs (German Shepherd breed) and to assess whether a dietary supplement improves their physical fitness. During a drug detection dog training course, seven dogs were fed with a basal diet (Control Group) for three-month period, while a further seven dogs were fed with a basal diet as well as a daily nutritional supplement containing branched-chain and limiting amino acids, carnitine, vitamins, and octacosanol (Treatment Group). At the end of this period, individual physical fitness was assessed by making each subject take a graded treadmill exercise test. A human heart rate monitor system was used to record the dog's heart rate (HR) during the treadmill exercise and the subsequent recovery period. The parameters related to HR were analysed using nonparametric statistics. Blood samples were collected before starting the nutritional supplement treatment, before and after the treadmill exercise and following recovery. Linear mixed models were used. The dietary supplements accelerated HR recovery, as demonstrated by the lower HR after recovery (P<0.05) and Time constants of HR decay (P<0.05), and by the higher Absolute HR Recovered (P<0.05) recorded in the Treatment group compared with the Control dogs. The supplemented dogs showed the lowest concentrations of creatine kinase (CK; P<0.001), aspartate aminotransferase (AST, P<0.05) and non-esterified fatty acids (NEFA; P<0.01) suggesting a reduction in muscle damage and improvement of energy metabolism. These data suggest that this combined supplement can significantly enhance the physical fitness of drug detection dogs

    The Oncological Implication of Sentinel Lymph Node in Early Cervical Cancer: A Meta-Analysis of Oncological Outcomes and Type of Recurrences

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    Background and Objectives: Pelvic lymphadenectomy has been associated with radical hysterectomy for the treatment of early Cervical Cancer (ECC) since 1905. However, some complications are related to this technique, such as lymphedema and nerve damage. In addition, its clinical role is controversial. For this reason, the sentinel lymph node (SLN) has found increasing use in clinical practice over time. Oncologic safety, however, is debated, and there is no clear evidence in the literature regarding this. Therefore, our meta-analysis aims to schematically analyze the current scientific evidence to investigate the non-inferiority of SLN versus PLND regarding oncologic outcomes. Materials and Methods: Following the recommendations in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, we systematically searched the PubMed and Scopus databases in June 2022 since their early first publications. We made no restrictions on the country. We considered only studies entirely published in English. We included studies containing Disease-Free Survival (DFS), Overall Survival (OS), Recurrence Rate (RR), and site of recurrence data. We used comparative studies for meta-analysis. We registered this meta-analysis to the PROSPERO site for meta-analysis with protocol number CRD42022316650. Results: Twelve studies fulfilled inclusion criteria. The four comparative studies were enrolled in meta-analysis. Patients were analyzed concerning Sentinel Lymph Node Biopsy (SLN) and compared with Bilateral Pelvic Systematic Lymphadenectomy (PLND) in early-stage Cervical Cancer (ECC). Meta-analysis highlighted no differences in oncological safety between these two techniques, both in DFS and OS. Moreover, most of the sites of recurrences in the SLN group seemed not to be correlated with missed lymphadenectomy. Conclusions: Data in the literature do not seem to show clear oncologic inferiority of SLN over PLND. On the contrary, the higher detection rate of positive lymph nodes and the predominance of no lymph node recurrences give hope that this technique may equal PLND in oncologic terms, improving its morbidity profile

    The blue lizard spandrel and the island syndrome

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    <p>Abstract</p> <p>Background</p> <p>Many small vertebrates on islands grow larger, mature later, lay smaller clutches/litters, and are less sexually dimorphic and aggressive than their mainland relatives. This set of observations is referred to as the 'Island Syndrome'. The syndrome is linked to high population density on islands. We predicted that when population density is low and/or fluctuating insular vertebrates may evolve correlated trait shifts running opposite to the Island Syndrome, which we collectively refer to as the 'reversed island syndrome' (RIS) hypothesis. On the proximate level, we hypothesized that RIS is caused by increased activity levels in melanocortin receptors. Melanocortins are postranslational products of the proopiomelanocortin gene, which controls pleiotropically pigmentation, aggressiveness, sexual activity, and food intake in vertebrates.</p> <p>Results</p> <p>We tested the RIS hypothesis performing a number of behavioral, genetic, and ontogenetic tests on a blue colored insular variant of the Italian Wall lizard <it>Podarcis sicula</it>, living on a small island off the Southern Italian coast. The population density of this blue-colored variant was generally low and highly fluctuating from one year to the next.</p> <p>In keeping with our predictions, insular lizards were more aggressive and sexually dimorphic than their mainland relatives. Insular males had wide, peramorphic heads. The growth rate of insular females was slower than growth rates of mainland individuals of both sexes, and of insular males. Consequently, size and shape dimorphism are higher on the Island. As predicted, melanocortin receptors were much more active in individuals of the insular population. Insular lizards have a higher food intake rate than mainland individuals, which is consistent with the increased activity of melanocortin receptors. This may be adaptive in an unpredictable environment such as Licosa Island. Insular lizards of both sexes spent less time basking than their mainland relatives. We suspect this is a by-product (spandrel) of the positive selection for increased activity of melanocortins receptors.</p> <p>Conclusions</p> <p>We contend that when population density is either low or fluctuating annually as a result of environmental unpredictability, it may be advantageous to individuals to behave more aggressively, to raise their rate of food intake, and allocate more energy into reproduction.</p

    Fertility-Sparing Treatment for Early-Stage Cervical Cancer ≥ 2 cm: A Problem with a Thousand Nuances—A Systematic Review of Oncological Outcomes.

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    BACKGROUND: Fertility-sparing treatments (FSTs) have played a crucial role in the management of early-stage cervical cancer (ECC). The guidelines have recognized various approaches, depending on the tumor stage and other risk factors such as histotype and lymphovascular positivity. Much more debate has centered around the boundary within which these treatments should be considered. Indeed, these are methods to be reserved for ECC, but tumor size may represent the most significant limitation. In particular, there is no consensus on the strategy to be adopted in the case of ECC ≥ 2 cm. Therefore, this systematic review was to collect the literature evidence regarding the management of these patients. METHODS: Following the recommendations in the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, we systematically searched the Pubmed and Scopus databases was conducted in April 2022, from the date of the first publication. We made no limitation on the country. We included all studies containing data on disease-free survival, overall survival, recurrence rate (RR), or complete response rate (CRR) to chemotherapy. RESULTS: Twenty-six studies fulfilled the inclusion criteria, and 691 patients were analyzed regarding FST. Surgery-based FST showed an RR of between 0 and 42.9%, which drops to 12.9% after excluding the vaginal or minimally invasive approaches. Furthermore, papers regarding FST based on the neoadjuvant chemotherapy (NACT) approach showed a CRR of between 21.4 and 84.5%, and an RR of between 0 and 22.2% CONCLUSION: This paper focused on the significant heterogeneity present in the clinical management of FST of ECC ≥ 2 cm. Nevertheless, from an oncological point of view, approaches limited to the minimally invasive or vaginal techniques showed the highest RR. Vice versa, the lack of standardization of NACT schemes and the wealth of confounders to be attributed to the histological features of the tumor make it difficult, if not impossible, to set a standard of treatment. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1245/s10434-022-12436-w
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