1,340 research outputs found

    The Cagliari Airport impact on Sardinia tourism: a Logit-based analysis

    Get PDF
    In the field of air transportation management, traditionally, airlines have been the main actors in the process for deciding which new flights open in a given airport, while airports acted only as the managers of the operations. The changes in the market due to the introduction of low cost companies, with consequent reduction of the airports' fares, as well as the increment of the density of regional airports in several European countries are modifying the mutual roles of airlines and airports. The final decision on new flight to be opened, in fact, is nowadays the result of a negotiation between airlines and airports. The airports must prove the sustainability on the new routes and forecast the economic impact on their catchment area. This paper contributes to advance the current state-of-the-art along two axes. From the pure transportation literature point of view, we introduce a Logit model able to predict the passengers flow in an airport when the management introduces a change in the flight schedule. The model is also able to predict the impact of this change on the airports in the surrounding areas. The second contribution is a case study on the tourist market of the Sardinia region, where we show how to use the results of the model to deduce the economic impact of the decisions of the management of the Cagliari airport on its catchment area in terms of tourists and economic growt

    A DSS for business decisions in air transportation: a case study

    Get PDF
    The socio-economic development leads people to a great mobility. Thus the flights identification and management is becoming a key factor for the economic growth of the areas nearby the airports. The airport management is constantly looking for methods to improve its performance, both in terms of profitability and quality of service and the proper planning of passenger flows. To address these issues, scientific research provides methods and tools for decision support at all planning levels (i.e., strategic, tactical, operational, real time). In recent literature, it is now widely recognized that the hybridization of simulation and optimization systems is a very reliable technique for such decisions. This work intends to present an efficient Decision Support System framework based on the hybridization of a discrete event simulator and a Logit model. In order to show the effectiveness of the framework, we show the results of a real case study in North Ital

    Injerto óseo en bloque usando como donante torus mandibular. Reporte de caso

    Get PDF
    Actualmente los materiales empleados para regeneración a través de injertos óseos están basados en compuestos sintéticos con propiedades en ocasiones poco predecibles para los pacientes. Los torus son exostosis óseas de etiología desconocida y pueden ser utilizados como injertos óseos con resultados clínicos exitosos. Así, el objetivo de este reporte de caso es describir la técnica quirúrgica de injerto óseo en bloque utilizando como donante torus mandibulares. Los resultados clínicos a 8 semanas postoperatorias evidenciaron tejidos en cicatrización y pocas molestias referidas por el paciente. Los injertos óseos provenientes de torus mandibulares son técnicas quirúrgicas de mediana complejidad que pueden ser empleados y permiten la obtención de resultados clínicos similares a los de otros materiales

    Search term “One Health” remains of limited use to identify relevant scientific publications: Denmark as a case study

    Get PDF
    One Health has become a popular approach, and scientific advancements in the field should be easily findable and accessible to a wide range of relevant audiences, from researchers to policymakers, and across sectors. We conducted a systematic narrative review of available scientific publications concerning One Health in the setting of Denmark that were retrievable using “One Health” as the key search term. Three searches in two databases yielded 30 retrieved publications, 13 of which were included in the review. The included publications had been published between 2015 and 2021. Twelve of the included publications were co-authored in collaboration across institutes from different sectors. Three of the included publications had focus on antimicrobial resistance, three on disease surveillance and/or control, and five were assessments or evaluations. The overall number of publications identified by a search using “One Health” as the key search term was small, and the search identified some publications that were not relevant to One Health. Our work thus highlights a missed scientific and communication opportunity of signposting articles as relevant to One Health. Using the expression “One Health” as keyword could help making One Health research more easily findable and thereby obtaining an overview of research in the field

    Cryopreservation protocol for human biliary tree stem/progenitors, hepatic and pancreatic precursors

    Get PDF
    Human biliary tree stem/progenitor cells (hBTSCs) are being used for cell therapies of patients with liver cirrhosis. A cryopreservation method was established to optimize sourcing of hBTSCs for these clinical programs and that comprises serum-free Kubota's Medium (KM) supplemented with 10% dimethyl sulfoxide (DMSO), 15% human serum albumin (HSA) and 0.1% hyaluronans. Cryopreserved versus freshly isolated hBTSCs were similar in vitro with respect to self-replication, stemness traits, and multipotency. They were able to differentiate to functional hepatocytes,cholangiocytes or pancreatic islets, yielding similar levels of secretion of albumin or of glucose-inducible levels of insulin. Cryopreserved versus freshly isolated hBTSCs were equally able to engraft into immunocompromised mice yielding cells with human-specific gene expression and human albumin levels in murine serum that were higher for cryopreserved than for freshly isolated hBTSCs. The successful cryopreservation of hBTSCs facilitates establishment of hBTSCs cell banking offering logistical advantages for clinical programs for treatment of liver diseases

    High level triggers for explosive mafic volcanism: Albano Maar, Italy

    Get PDF
    Colli Albani is a quiescent caldera complex located within the Roman Magmatic Province (RMP), Italy. The recent Via dei Laghi phreatomagmatic eruptions led to the formation of nested maars. Albano Maar is the largest and has erupted seven times between ca 69-33ka. The highly explosive nature of the Albano Maar eruptions is at odds with the predominant relatively mafic (SiO2=48-52wt.%) foiditic (K2O=9wt.%) composition of the magma. The deposits have been previously interpreted as phreatomagmatic, however they contain large amounts (up to 30%vol) of deep seated xenoliths, skarns and all pre-volcanic subsurface units. All of the xenoliths have been excavated from depths of up to 6km, rather than being limited to the depth at which magma and water interaction is likely to have occurred, suggesting an alternative trigger for eruption. High precision geochemical glass and mineral data of fresh juvenile (magmatic) clasts from the small volume explosive deposits indicate that the magmas have evolved along one of two evolutionary paths towards foidite or phonolite. The foiditic melts record ca. 50% mixing between the most primitive magma and Ca-rich melt, late stage prior to eruption. A major result of our study is finding that the generation of Ca-rich melts via assimilation of limestone, may provide storage for significant amounts of CO2 that can be released during a mixing event with silicate magma. Differences in melt evolution are inferred as having been controlled by variations in storage conditions: residence time and magma volume. © 2013

    When variability varies: Heteroscedasticity and variance functions

    Get PDF
    La variabilidad es una característica inherente al mundo que nos rodea. Cuantificarla es clave para comprender muchos de los procesos de interés para las ciencias ambientales y sociales como, por ejemplo, la adaptación de las especies al cambio climático o la desigualdad social. Para cuantificar la variabilidad se suele usar la varianza, uno de los parámetros de la distribución normal. Sin embargo, los modelos lineales clásicos asumen que la varianza es constante (supuesto de homocedasticidad) y se preocupan sólo por los cambios en las tendencias promedio. Es posible extender los modelos clásicos y relajar el supuesto de homocedasticidad mediante funciones de varianza, muy poco difundidas y abordadas por los textos en español. En esta ayuda didáctica nos proponemos introducir las funciones de varianza en modelos lineales desde un enfoque teóricoaplicado. Comenzamos introduciendo un problema real en el que se espera que la varianza no sea constante, y lo acompañamos con un ejemplo simulado. Posteriormente, planteamos el modelo lineal clásico y discutimos cómo se lo puede extender para modelar la heterocedasticidad. A continuación, explicamos algunas de las funciones de varianza y las aplicamos al caso real y a los datos simulados. Para ello hacemos uso de la función gls() del paquete nlme de R y proveemos el código para la reproducción del análisis. También exponemos otras opciones disponibles en R para tratar con datos heterocedásticos. Esperamos que este artículo brinde las bases para que profesionales y científicos con conocimientos estadísticos básicos comiencen a utilizar funciones de varianza y amplíen el conjunto de herramientas para analizar sus datos.Variability is inherent to the world around us. Its quantification is essential to understand processes of interest in environmental and social sciences, such as adaptation of species to climate change or social inequality. Variance, one of the parameters of the normal distribution, is commonly used to quantify variability. Classical linear models assume that variance is constant (homoscedasticity assumption), while focusing only on changes in average trends. It is possible to extend classical models and relax the assumption of homoscedasticity through variance functions. However, these functions are scarcely used and we often lack examples in the Spanish-wri�en scientific literature. In this paper, we introduce variance functions in linear models from a theoretical-applied approach. We begin by introducing a real problem where heteroscedasticity is expected, which is accompanied by one simulated example. Subsequently, we formulate the classical linear model and discuss how it can be extended to model heteroscedasticity. Then, we explain some of the variance functions and apply them to the real case and the simulated data. We use the gls() function of the nlme package in R, and provide scripts that make data analyses reproducible. Additionally, we describe other options available in R for dealing with heteroscedastic data. We expect this paper will provide a guide for using variance functions and will expand the toolbox of scientists with basic statistical knowledge.Fil: Oddi, Facundo José. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural. - Universidad Nacional de Rio Negro. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural; ArgentinaFil: Miguez, Fernando E.. University of Iowa; Estados UnidosFil: Benedetti, Guido. Universidad Nacional de Río Negro. Sede Andina. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural; ArgentinaFil: Garibaldi, Lucas Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural. - Universidad Nacional de Rio Negro. Instituto de Investigaciones en Recursos Naturales, Agroecología y Desarrollo Rural; Argentin

    Oseointegración en implantes Bicon® cargados a los tres meses después de haber sido colocados mediante la técnica de elevación interna del seno maxilar en pacientes atendidos en la facultad de odontología de la universidad de Cartagena

    Get PDF
    Objective: The general objective of this investigation was to evaluate the oseointegration of Bicon® dental implants that have been charge after three month of put it with internal sinus lift in maxillary sinus Material and Methods: This investigation has been stablished as a descriptive study, support in clinic cases. In order to recollect the information, a format was used to register the personal date of the patient that could be important to achieve this study. Panoramic radiograph were also taken before and after the procedure to evaluate the raise in the height of the maxillary sinus; periapical radiograph were also taken to evaluate the osseointegration of the implant. The information was decodificated and tabulate in frequency tables and graphics. Results: Three months after the procedures it was found that during the first control the height maxillary sinus floor increased to 2.5mm in average. During the evaluate of mobility and pain the behavian was favorable with abscense of this characteristics in the all patients. The study of the periapical radiographs demonstrated abscense of radiolucences zones around the implant and spongy bone travecules were observe in the different stages of formation. Conclusions: We could determinate that three months after to place the Bicon® dental implant, it got enought oseointegration due internal sinus lift tecnique, and the good grade of bone formation gave us the security to charge them in a short time of usual.Objetivo: El objetivo general de este estudio fue evaluar la oseointegración en implantes tipo Bicon® cargados a los tres meses de colocados, mediante la técnica de elevación interna de seno maxilar. Materiales y Métodos: Este estudio se establece como una investigación de tipo descriptivo, basado en una serie de casos clínicos tratados. En la recolección de la información se utilizó un instrumento en donde se registraron los datos personales de los pacientes, se realizó la toma de radiografías panorámicas iniciales y radiografías periapicales utilizadas para observar la neoformación ósea y medir el aumento del piso del seno maxilar. La información fue consignada y tabulada en tablas y gráficos de frecuencia. Resultados: De los implantes colocados ninguno presentó movilidad ni patologías perimplantares, el piso del seno maxilar se aumentó en promedio 2.6 mm y se presentó neoformación ósea adecuada a los tres meses, lo que permitió la carga de los implantes. Conclusiones: Se determinó que a los tres meses se logra una suficiente oseointegración con los implantes, que en conjunto con la elevación interna del piso del seno maxilar y el grado de neoformación ósea alcanzado dieron a los implantes las condiciones necesarias para poder cargar los mismos. Además, la ausencia total de lesiones perimplantarias señalan el cumplimiento estricto de las normas tecnoquirurgicas, evaluación e instrucción a los pacientes que se han estado manejando dentro del proceso de la colocación de los implante
    corecore