1,090 research outputs found
The Contribution of Air Logistics to the Development of Sicilian Economy
The role, played by globalization and the “just in time” supplying logic in present world economic scenario, implies that the opportunity of frequent, quick, safe and low-priced freight deliveries can be considered a key element for competitiveness. For these reasons, transportation systems, in the last years, have been characterized by the diffusion of intermodality and the “hub and spoke” distribution pattern. The phenomenon of organizing freight transport services according to a network and modal integration logic, has involved also the air transport field: to meet the new requirements of freight transportation market, in many cases, airline companies have become “global players”, expanding their network, in order to develop links among the main economic centres in the world. The goods moving by air can be defined as “top range products”; which means that only high value products (“market value” and “need value”) and the perishable ones (from a physical and economic point of view) demand air transport. The research described in this abstract aims at determining the contribution that can derive from air logistics to face a challenging problem: overcoming the peripheral role, in international trade, played by Sicily, which can boast high quality outputs in the agroindustrial sector and in the high technology one. The research consists of the following stages: 1. Analysing the sicilian freight transport system, with regard to the demand-supply relationship, paying particular attention to the commodity typologies mentioned above. 2. Identifying key actions for the air cargo services, in order to make Sicily improve in competitiveness, also taking into account the possibility of connecting Sicily with hub airports. 3. Determining the economic and social impact of the proposed solutions, considering different evolutionary scenarios and using also input-output analysis techniques.
IL RUOLO DELLA QUALITĂ€ PERCEPITA DEI PERCORSI PEDONALI NELLA SCELTA DEL TRASPORTO PUBBLICO
Il fenomeno del pendolarismo oggigiorno coinvolge ampie fasce della popolazione,
manifestandosi attraverso spostamenti sistematici, spesso quotidiani, dal proprio luogo di residenza verso altra destinazione, per motivi di studio o di lavoro. La definizione di spostamento pendolare prescinde dalla distanza percorsa o dal tempo di viaggio.
Tipicamente, i pendolari si spostano tra differenti aree di regioni metropolitane, seguendo percorsi multimodali, costituiti anche da itinerari di “mobilità dolce” (pedonale o ciclabile). La mancanza di una cultura della pianificazione urbanistica, la diffusione sul territorio delle funzioni residenziali e l’accentramento delle attività produttive e commerciali hanno determinato, negli ultimi decenni, una crescita intensa dei fenomeni di pendolarismo.
A causa del notevole sviluppo dei centri urbani, divenuti delle vere e proprie “città diffuse”, la durata degli spostamenti pendolari ha subito forti incrementi, occupando, in molti casi, gran parte della vita dei viaggiatori. Il pendolarismo, inoltre, è considerato uno dei fattori che maggiormente contribuiscono all’inquinamento atmosferico, a causa della congestione della rete stradale metropolitana. Ne deriva un crescente degrado della “qualità ” della vita per gli stessi pendolari e per gli individui residenti nelle aree limitrofe alle grandi arterie di collegamento. Per risolvere questi problemi, si è da tempo affermato l’orientamento ad elaborare politiche per la promozione dell’uso del trasporto collettivo, volte, in particolare, a conseguire miglioramenti dei servizi pubblici sia sul piano dell’efficienza sia su quello dell’efficacia. Tuttavia, in generale, l’attenzione è rivolta alla progettazione dell’offerta del singolo modo di trasporto pubblico, senza considerare l’integrazione con altre forme di trasporto collettivo e con le modalità di “mobilità dolce”. Ne discende una scarsa competitività dei servizi di trasporto pubblico, con la conseguenza di una ripartizione modale molto sbilanciata a favore dell’auto
Car sharing demand estimation and urban transport demand modelling using stated preference techniques
The research deals with the use of the stated preference technique (SP) and transport demand modelling
to analyse travel mode choice behaviour for commuting urban trips in Palermo, Italy.
The principal aim of the study was the calibration of a demand model to forecast the modal split of the
urban transport demand, allowing for the possibility of using innovative transport systems like car sharing
and car pooling.
In order to estimate the demand model parameters, a specific survey was carried out inside the urban
area of Palermo. The survey focused on the morning rush hour and involved mainly employees, selfemployed
workers and students (about 500 respondents) whose final destination was located within the
historical centre of the city. The questionnaires contained a stated preference experiment regarding the
choice among four different transport alternatives: private car, car pooling, car sharing and public
transport.
A random utility model was developed by using data resulting from the SP experiment. We found out
that, for the specific case of Palermo, the multinomial logit proved to be the best urban transport demand
model, even if the choice set contained three car alternatives. We identified as main attributes affecting
mode choice behaviour the one-way trip travel time and cost, the parking time, the number of cars
available to each household member, the alternative specific attributes for the car option and the car
sharing one.
The model was applied to analyse the potential demand for car sharing and car pooling in Palermo,
under a future scenario characterized by several policy actions for limiting private transport use. The
analysis highlighted that the car club market share could increase up to the 10% level, while car pooling
could slightly rise
Utilização de uma guia cirúrgica no tratamento endodôntico cirúrgico mediante a utilização do CBCT: revisão narrativa
A cirurgia endodĂ´ntica Ă© um procedimento complementar da terapia endodĂ´ntica, que visa a resolução de situações em que os tratamentos endodĂ´nticos convencionais falharam ou que se tornaram impossĂveis de realizar, nĂŁo permitindo o correto acesso clĂnico Ă zona apical da raiz.
Com a evolução das técnicas cirúrgicas, das tecnologias empregues na Medicina Dentaria, os procedimentos tornaram-se cada vez menos invasivos, mais precisos e seguros.
Este trabalho tem como objetivo principal estudar e apresentar um novo método de microcirurgia endodôntica, usando imagem tomográfica computadorizada de feixe cónico (CBCT) e uma digitalização ótica 3D das arcadas, para realização de guias pré-fabricadas que orientam o acesso apical durante a microcirurgia-endodôntica e ao mesmo tempo, comparar a sua precisão com a do método não guiado.
Foram utilizados 54 artigos dos 68 que cumpriam os pressupostos estipulados. Os critérios de exclusão foram publicações das quais o conteúdo não teria relevância para a concretização do trabalho.Endodontic surgery is a complementary procedure to endodontic therapy, which aims to resolve situations in which conventional endodontic treatments have failed or have become impossible to perform, not allowing the correct access to the root apex.
With the evolution of surgical techniques and technologies used in dentistry, procedures have become less and less invasive, more accurate and safer.
This articles’ main objective is to study and present a new method of endodontic microsurgery, using conical beam computed tomographic image (CBCT) and a 3D optical scan of the arches, for the realization of prefabricated guides to guide the apical access during endodontic microsurgery and at the same time, compare its accuracy with that of the unguided method
Single injection dual phase CBCT technique ameliorates results of trans-arterial chemoembolization for hepatocellular cancer
Cone-beam CT (CBCT) application to the field of trans-arterial chemoembolization has been recently the focus of several researches. This imaging modality is performed with a rotation of the C-arm around the patient, without needs of patient repositioning. Datasets are immediately processed, obtaining volumetric CT-like images with the possibility of post-processing and reconstruction of images. Dual phase CBCT recently introduced in clinical practice consists in a first arterial acquisition followed by a delayed acquisition corresponding to a venous phase. The introduction of this feature has overcome the limit of single-phase acquisitions, allowing lesions characterization. Moreover these recent advantages have several intra-procedural implications. Detailed technical and acquisition parameters will be widely exposed in this review with particular attention to: catheter positioning, acquisition delay, injection parameters, patient positioning and contrast dilution. Comparison with standard of practice second line imaging [multidetector computer tomography (MDCT) and MDCT/arteriography] demonstrate the capability of detecting occult nodules providing some clinical implications thus potentially identifying a sub set of patients with aggressive disease behaviour. Other intra-procedural advantages of dual phase CBCT usage consist in a better tumor feeder visualization, reduction of proper DSA and fluoroscopic time, suggestion the presence of an extrahepatic parasitic feeder thus resulting in a more accurate treatment. Finally, the volumetrical intraprocedural evaluation of accumulation of embolic agent has proved to be correlate with treatment response if compared with MRI
Comparison of magnetic resonance spectroscopy, proton density fat fraction and histological analysis in the quantification of liver steatosis in children and adolescents
AIM:
To establish a threshold value for liver fat content between healthy children and those with non-alcoholic fatty liver disease (NAFLD) by using magnetic resonance imaging (MRI), with liver biopsy serving as a reference standard.
METHODS:
The study was approved by the local ethics committee, and written informed consent was obtained from all participants and their legal guardians before the study began. Twenty-seven children with NAFLD underwent liver biopsy to assess the presence of nonalcoholic steatohepatitis. The assessment of liver fat fraction was performed using MRI, with a high field magnet and 2D gradient-echo and multiple-echo T1-weighted sequence with low flip angle and single-voxel point-resolved ÂąH MR-Spectroscopy (ÂąH-MRS), corrected for T1 and T2* decays. Receiver operating characteristic curve analysis was used to determine the best cut-off value. Lin coefficient test was used to evaluate the correlation between histology, MRS and MRI-PDFF. A Mann-Whitney U-test and multivariate analysis were performed to analyze the continuous variables.
RESULTS:
According to MRS, the threshold value between healthy children and those with NAFLD is 6%; using MRI-PDFF, a cut-off value of 3.5% is suggested. The Lin analysis revealed a good fit between the histology and MRS as well as MRI-PDFF.
CONCLUSION:
MRS is an accurate and precise method for detecting NAFLD in children
A demand-based methodology for planning the bus network of a small or medium town
This work aims at developing a demand-based methodology for designing the bus network of a small
or medium town. The proposed modelling tool adopts a multi-agent objective function which evaluates
performance in the context of different stakeholders: the surplus of travellers (car and bus users); the bus
service provider’s revenues and operation costs. This approach was applied to an existing bus network,
serving Trapani, which is a medium town in the south of Italy (Sicily), with 100000 inhabitants. The busbased
public transport system attracts only about 5% of commuter trips within Trapani (source: National
Institute of Statistics, 2005). This paper reports on an analysis of the application of the proposed multiagent
modelling tool to two planning scenarios: the first is short-term and characterized by a budget
constraint (slight changes in the availability of drivers and vehicles) and the second long-term with new
investments in new buses to improve services and increase patronage. In both cases, the impact of the
recent car park charging policy launched by the local administration was considered.
The decision variables for the optimisation procedure were route, service frequency and capacity of
each bus line. A random utility model was employed to forecast the mode choices for trips within Trapani
and the travel demand-supply equilibrium was obtained using the DUE (deterministic user equilibrium)
assignment algorithm, for private transport, and the hyperpath network loading algorithm, for public
transport.
The optimisation procedure led to a more efficient bus network characterized by increase in bus
frequencies and a better performance in terms of reduced travel time, especially for trips bound for the
“old town” in the morning. In addition, a higher number of origin-destination pairs were served, at the
expense of the need to interchange between the inner more frequent and the outer less frequent services.
This implied that the number of transfers from one bus line to another significantly increased
Risk Factors for Immediate and Delayed-Onset Fever After Percutaneous Transhepatic Biliary Drainage
Objectives To prospectively investigate the pre and intraprocedural risk factors for immediate (IF) and delayedonset (DOF) fever development after percutaneous transhepatic biliary drainage (PTBD).
Methods Institutional review board approval and
informed patient consent were obtained. Between February
2013 and February 2014, 97 afebrile patients (77 at the
Sapienza University of Rome, Italy and 20 at the Sun Yatsen University of Guangzhou, China) with benign (n = 31)
and malignant (n = 66) indications for a first PTBD were
prospectively enrolled. Thirty pre- and intra-procedural
clinical/radiological characteristics, including the amount
of contrast media injected prior to PTBD placement, were
collected in relation to the development of IF (within 24 h)
or DOF (after 24 h). Fever was defined as C37.5 C.
Binary logistic regression analysis was used to assess
independent associations with IF and DOF.
Results Fourteen (14.4 %) patients developed IF and 17
(17.5 %) developed DOF. At multivariable analysis, IF
was associated with pre-procedural absence of intrahepatic
bile duct dilatation (OR 63.359; 95 % CI 2.658–1510.055;
P = 0.010) and low INR (OR 4.7 9 10-4
; 95 % CI
0.000–0.376; P = 0.025), while DOF was associated with
unsatisfactory biliary drainage at the end of PTBD (OR
4.571; 95 % CI 1.161–17.992; P = 0.030)
Innovative transport services in areas with weak and peculiar public transport demand
A growing demand for mobility and the deficiencies in the transport system have transformed urban centres in “unliveable” places. A prevalent use of private cars produces high levels of pollution, casualties and road congestion. The promotion of public transport is considered an effective strategy to make mobility more sustainable for people. When a public transport system serves areas with a
weak transportation demand, as it happens in territories with dispersed settlements (urban outskirts, rural areas, mountains, …), the resort to unconventional forms of public transport, such as dial and ride bus services, is necessary
The analysis of urban travellers' latent preferences to explain their mode choice behaviour.
Our research aims to explore the impact of latent variables, mirroring urban travellers’ attitudes and perceptions, on the individual decision making process
regarding the mode of transport. The paper describes the first results of an ongoing research activity, which derive from a pilot study conducted in Palermo,
the capital of the Sicilian Region (in the south of Italy), and demonstrate that policy makers, in designing a socially desirable and environmentally sustainable
urban mobility system, should take into account how travellers perceive the qualitative dimensions of transport
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