8,577 research outputs found
An Analytic Hierarchy Process for The Evaluation of Transport Policies to Reduce Climate Change Impacts
Transport is the sector with the fastest growth of greenhouse gases emissions, both in developed and in developing countries, leading to adverse climate change impacts. As the experts disagree on the occurrence of these impacts, by applying the analytic hierarchy process (AHP), we have faced the question on how to form transport policies when the experts have different opinions and beliefs. The opinions of experts have been investigated by a means of a survey questionnaire. The results show that tax schemes aiming at promoting environmental-friendly transport mode are the best policy. This incentives public and environmental-friendly transport modes, such as car sharing and car pooling.Analytic Hierarchy Process, Transport Policies, Climate Change
Finding Large Independent Sets in Line of Sight Networks
Line of Sight (LoS) networks provide a model of wireless communication which incorporates visibility constraints. Vertices of such networks can be embedded in finite d-dimensional grids of size n, and two vertices are adjacent if they share a line of sight and are at distance less tha
Growth of ZnO nanolayers inside the capillaries of photonic crystal fibres
In this study, we describe the formation of ZnO nanolayers inside the air
capillaries of a silica photonic crystal fibre (PCF), targeting random laser
and organic vapor sensing applications. ZnO nanolayers were developed by
infiltrating the capillaries of the silica PCF with Zn-acetate/methanol
solutions of various concentrations, followed by annealing treatments. The
growth and morphology of the synthesized ZnO nanolayers were characterized by
means of scanning electron microscopy (SEM) and found to be affected by the
concentration of the Zn-acetate/methanol infiltration solution. For low
concentrations, inspection with SEM revealed the formation of 25 and
100-nm-thick ZnO nanolayers across the entire length of the infiltrated
capillaries, whereas increasing the Zn-acetate concentration resulted to the
formation of randomly placed isolated ZnO nanorods. Room temperature
photoluminescence spectra of the ZnO nanolayers inside the PCF were measured
and compared with the corresponding spectra reported for ZnO structures formed
on typical surfaces.Comment: 5 pages, 5 figures, Available online 29 June 2013, in press. Thin
Solid Film, Elsevier, Available online 29 June 201
Frictionless contact formulation by mathematical programming technique
The object of the paper concerns a consistent formulation of the classical Signorini's theory
regarding the frictionless unilateral contact problem between two elastic bodies in the hypothesis of
small displacements and strains. A variational approach, employed within the symmetric Boundary
Element Method, leads to an algebraic formulation based on nodal quantities. The contact problem
is decomposed into two sub-problems: one is purely elastic, and the other pertains to the unilateral
contact condition alone. Following this methodology, the contact problem, faced with symmetric
BEM, is characterized by symmetry and sign definiteness of the coefficient matrix, thus admitting a
unique solution.
The solution of the frictionless unilateral contact problem can be obtained
- through a step-by-step analysis utilizing generalized quantities as check elements in the zones of
potential contact or detachment. Indeed, the detachment or the contact phenomenon may happen
when the weighted traction or the weighted displacement is greater than the weighted cohesion
or weighted minimum reference gap, respectively;
- through a quadratic programming problem based on the minimum of the total potential energy.
In the example, given in the paper, the detachment phenomenon is considered and some
comparisons of the solution between the step-by-step analysis and the direct approach which utilizes
the quadratic programming will be shown
Street crossing behavior in younger and older pedestrians: an eye- and head-tracking study
Background Crossing a street can be a very difficult task for older pedestrians. With increased age and potential cognitive decline, older people take the decision to cross a street primarily based on vehicles’ distance, and not on their speed. Furthermore, older pedestrians tend to overestimate their own walking speed, and could not adapt it according to the traffic conditions. Pedestrians’ behavior is often tested using virtual reality. Virtual reality presents the advantage of being safe, cost-effective, and allows using standardized test conditions. Methods This paper describes an observational study with older and younger adults. Street crossing behavior was investigated in 18 healthy, younger and 18 older subjects by using a virtual reality setting. The aim of the study was to measure behavioral data (such as eye and head movements) and to assess how the two age groups differ in terms of number of safe street crossings, virtual crashes, and missed street crossing opportunities. Street crossing behavior, eye and head movements, in older and younger subjects, were compared with non-parametric tests. Results The results showed that younger pedestrians behaved in a more secure manner while crossing a street, as compared to older people. The eye and head movements analysis revealed that older people looked more at the ground and less at the other side of the street to cross. Conclusions The less secure behavior in street crossing found in older pedestrians could be explained by their reduced cognitive and visual abilities, which, in turn, resulted in difficulties in the decision-making process, especially under time pressure. Decisions to cross a street are based on the distance of the oncoming cars, rather than their speed, for both groups. Older pedestrians look more at their feet, probably because of their need of more time to plan precise stepping movement and, in turn, pay less attention to the traffic. This might help to set up guidelines for improving senior pedestrians’ safety, in terms of speed limits, road design, and mixed physical-cognitive trainings
Essential oil of Cyphostemma juttae (Vitaceae): chemical composition and antitumor mechanism in triple negative breast cancer cells
The genus Cyphostemma (Planch.) Alston (Vitaceae) includes about 150 species distrib- uted in eastern and southern Africa and Madagascar. Some species are used in traditional medicine and their biological activities, including antiproliferative effects against cancer cell lines, have been demonstrated. To date no investigations on Cyphostemma essential oils have been carried out. Essential oils, which play important roles in plant defenses have been demonstrated to be active in the treatment of several human diseases and to enhance bioavability of other drugs. The aim of this paper was to identify the chemical composition of the essential oil of the leaves of Cyphostemma juttae (Dinter & Gilg) Desc. and to verify some biological activities on two triple negative breast cancer cell lines (MDA-MB-231, SUM 149), characterized by the over-expression of the transcription factor NF-κB. In the essential oil, obtained by hydrodistillation and analysed by gas chromatography-mass spectrometry, 39 compounds were detected and with phytol (30%) dominating the chemical composition. C. juttae essential oil reduced cell growth and showed a pro-oxidant activity in both cell lines. Moreover, C. juttae essential oil caused a substantial decrease of NF-κB activation and consequently a significant reduction of some NF-κB target genes. The present study shows for the first time the cytotoxic properties of C. juttae essential oil and highlight its avail- ability to interfere with NF-κB pathway, suggesting a potential therapeutic use in triple nega- tive breast cancers (TNBCs) of this essential oil
Ketogenic diet-induced weight loss is associated with an increase in vitamin d levels in obese adults
Vitamin D is an important micronutrient involved in several processes. Evidence has shown a strong association between hypovitaminosis D and cardio-metabolic diseases, including obesity. A ketogenic diet has proven to be very effective for weight loss, especially in reducing fat mass while preserving fat-free mass. The aim of this study was to investigate the effect of a ketogenic diet-induced weight loss on vitamin D status in a population of obese adults. We enrolled 56 obese outpatients, prescribed with either traditional standard hypocaloric Mediterranean diet (SHMD) or very low-calorie ketogenic diet (VLCKD). Serum 25(OH)D concentrations were measured by chemiluminescence. The mean value of serum 25-hydroxyvitamin D (25(OH)D) concentrations in the whole population at baseline was 17.8 +/- 5.6 ng/mL, without differences between groups. After 12 months of dietetic treatment, in VLCKD patients serum 25(OH)D concentrations increased from 18.4 +/- 5.9 to 29.3 +/- 6.8 ng/mL (p < 0.0001), vs 17.5 +/- 6.1 to 21.3 +/- 7.6 ng/mL (p = 0.067) in the SHMD group (for each kilogram of weight loss, 25(OH)D concentration increased 0.39 and 0.13 ng/mL in the VLCKD and in the SHMD groups, respectively). In the VLCKD group, the increase in serum 25(OH)D concentrations was strongly associated with body mass index, waist circumference, and fatty mass variation. In a multiple regression analysis, fatty mass was the strongest independent predictor of serum 25(OH)D concentration, explaining 15.6%, 3.3%, and 9.4% of its variation in the whole population, in SHMD, and VLCKD groups, respectively. We also observed a greater reduction of inflammation (evaluated by high-sensitivity C reactive protein (hsCRP) values) and a greater improvement in glucose homeostasis, confirmed by a reduction of HOMA values, in the VLCKD versus the SHMD group. Taken together, all these data suggest that a dietetic regimen, which implies a great reduction of fat mass, can improve vitamin D status in the obese
The Effect of Advanced Traveller Information Systems (ATIS) on public transport demand and its uncertainty
Advanced Traveller Information Systems (ATISs) include a broad range of advanced computer and communication technologies. These systems are designed to provide transit riders pre-trip and real-time information, to make better
informed decisions regarding their mode of travel, planned routes and travel times. ATISs include in-vehicle displays, terminal or wayside based information centres, information by phone or mobile and internet. In this article, a Stated
Preference survey has been carried out in order to know the preferences of public transport\u2019s customers related to different ATISs and their willingness to pay in Palermo. An ordered probit demand model has been calibrated to determine the potential additional share of demand attracted by the adoption of ATISs. Finally, Monte Carlo simulation has been carried out to appraise the uncertainty on some parameters of the calibrated demand model. The results show that respondents give more importance to the type of information and its cost, whereas they are less interested in the system that provides the information
Role of a Conserved Glutamate Residue in the \u3cem\u3eEscherichia coli\u3c/em\u3e SecA ATPase Mechanism
Escherichia coli SecA uses ATP to drive the transport of proteins across cell membranes. Glutamate 210 in the “DEVD” Walker B motif of the SecA ATP-binding site has been proposed as the catalytic base for ATP hydrolysis (Hunt, J. F., Weinkauf, S., Henry, L., Fak, J. J., McNicholas, P., Oliver, D. B., and Deisenhofer, J. (2002) Science 297, 2018–2026). Consistent with this hypothesis, we find that mutation of glutamate 210 to aspartate results in a 90-fold reduction of the ATP hydrolysis rate compared with wild type SecA, 0.3 s–1versus 27 s–1, respectively. SecA-E210D also releases ADP at a slower rate compared with wild type SecA, suggesting that in addition to serving as the catalytic base, glutamate 210 might aid turnover as well. Our results contradict an earlier report that proposed aspartate 133 as the catalytic base (Sato, K., Mori, H., Yoshida, M., and Mizushima, S. (1996) J. Biol. Chem. 271, 17439–17444). Re-evaluation of the SecA-D133N mutant used in that study confirms its loss of ATPase and membrane translocation activities, but surprisingly, the analogous SecA-D133A mutant retains full activity, revealing that this residue does not play a key role in catalysis
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