1,762 research outputs found
Integrating perceptions of safety and bicycle theft risk in the analysis of cycling infrastructure preferences
Cycling infrastructure development is an effective but expensive urban policy to encourage people to use bicycles. Although people usually prefer infrastructure with high cycling priority, authorities in some cities have focused policies on adapting part of current motor vehicle infrastructure to increase the length and coverage of bicycle infrastructure at the road level, which can help to lower infrastructure investment costs. Perceptions are also important in developing programs to promote cycling and they may even be more important for cyclists than the reality itself. In this research, we integrated the perceptions of cycling safety and theft risk into a hybrid discrete choice model in order to better understand cycling infrastructure preferences, using Bogota, a bike-friendly city with security concerns, as a case study. We found that concerns about safety are a significant deterrent to using bike lanes at the road level in the city while perceptions of theft risk affect the value or importance that bicyclists place on travel time. Based on modeling findings we proposed hard and soft measures to encourage bicyclists to use bike lanes at the road level
Biodiversidade nos quintais agroecológicos na zona rural da cidade de Foz do Iguaçu Paraná / Brasil
Anais do VI Encontro de Iniciação Científica e II Encontro Anual de Iniciação ao Desenvolvimento Tecnológico e Inovação – EICTI 2017 - 04 a 06 de outubro de 2017 - temática Ciências AgráriasO papel dos quintais nas zonas rurais são reservatórios da agrobiodiversidade
em comunidades rurais mundo afora. Em muitas culturas, as mulheres são as
responsáveis pela sustentação dessa arte e em outras oportunidades os homens.
Essa ocupação cotidiana constitui-se em uma formidável atividade doméstica,
cobrindo o acesso das famílias a uma dieta saudável e adequada ao gosto e às
tradições locais. As mulheres e os homens preservam a agrobiodiversidade através
de plantações em alta densidade de espécies subutilizadas de forma que seus
quintais se transformam em um laboratório de experiências para a adaptação de
variedades locais e não-domesticadasUniversidade Federal da Integração Latino-Americana (Unila); Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq); Fundação Araucária; Parque Tecnológico Itaipu (PTI) e Companhia de Saneamento do Paraná (SANEPAR
How do the affective and symbolic factors of private car driving influence car users’ travel behavior in a car restriction policy scenario?
The number of private car trips a person makes is usually linked to external factors such as economic incentives or disincentives, legislation, infrastructure, and the quality of transport systems, among others. The impact of these options are typically analyzed to evaluate urban transport policies and projects. However, internal factors related to an individuals' attitudes and perceptions also play an essential role in the amount of private car driving they do and on urban mobility as well. Therefore, insight into private car driving's affective and symbolic aspects is important in order to formulate appropriate transport policies and strategies to reduce car-use dependency and encourage private car drivers to use public transport. Congestion charging schemes make drivers pay the full social cost of driving, they achieve congestion reduction, pollution reduction, they make cities more attractive for pedestrians and cyclists, and help improve quality of life. Congestion charging schemes are often difficult to implement and expensive to administer. As a result of these reasons, several cities worldwide have adopted a variety of car restriction schemes that try to reduce air pollution and congestion as well, instead of establishing congestion charges. The effects of driving restrictions in the short term are positive, but in the medium and long term, there are unwanted consequences. However, by giving private car drivers the option to pay a toll so that their cars are exempted from the restriction, these perverse incentives could be eliminated. This paper analyzes the impacts of internal factors related to individuals' attitudes and perceptions about the travel behavior of car users affected by car restriction policies in urban areas. We designed a stated preference survey conducted among car owners in Cali, Colombia, where a License Plate Restriction Charging (LPRC) policy has been in place since January 2017. Through hybrid discrete choice modeling, we demonstrated that latent variables, such as the feelings of being in control, independence, and higher social status, positively influence the decision to use cars for daily trips, thus impacting the urban modal split. The heterogeneity captured through these latent variables allowed us to understand more deeply how individuals deal with the LPRC policy in order to travel to their destination
Analysis via Passivity Theory of a Class of Nonlinear PID Global Regulators for Robot Manipulators
Analysing a license plate-based vehicle restriction policy with optional exemption charge: The case in Cali, Colombia
Several cities have restricted the use of private vehicles based on the last digit of a vehicle's license plate to reduce traffic congestion and pollution. However, the effectiveness of this measure has been questioned. In 2017, a hybrid scheme, License Plate Restriction Charging (LPRC), was implemented in Cali, Colombia. With this scheme, drivers can pay a charge (monthly, quarterly, or yearly) to circumvent the restriction, while the revenue is used to subsidise the BRT System. Cali was the first city in Latin America to implement such a scheme, while Colombia's capital, Bogota, adopted a similar policy in 2020. This article analyses the evolution of the measure using official information. In addition, we conducted a stated preferences survey and estimated a choice model to evaluate the behaviour of car owners to policy variables. Results show that LPRC price is the most relevant attribute in decision-making. Increasing the number of days with traffic restrictions and extending the hours of vehicle use restriction increases drivers' probability of paying for the LPRC. As currently implemented in Cali, the LPRC is a fixed cost that does not vary according to the car use level, encouraging users who pay for the exemption to use their car as much as possible to make the most out of the payment. Furthermore, the revenue from the charge contributes only marginally to financing the BRT. Finally, we propose several changes in the policy to improve its efficiency. Among them, consider a daily payment and hardening the current driving restriction. © 2023 The Author(s)APCs y acuerdos transformativos 2023, Elsevie
T35: a small automatic telescope for long-term observing campaigns
The T35 is a small telescope (14") equipped with a large format CCD camera
installed in the Sierra Nevada Observatory (SNO) in Southern Spain. This
telescope will be a useful tool for the detecting and studying pulsating stars,
particularly, in open clusters. In this paper, we describe the automation
process of the T35 and show also some images taken with the new
instrumentation.Comment: 13 pages, 9 figures. Accepted for publication in the special issue
"Robotic Astronomy" of Advances of Astronom
Elasticidad de la demanda de estacionamiento ante variaciones sistemáticas del ingreso en Montería, Colombia
This article analyzes on-street and private parking lots demand elasticityin the central business district of Monteria, Colombia, when fee andincome variations are considered.Estimated choice models were based on a stated preference survey.Elasticities were analyzed using a multinomial logit model, whichexplanatory variables were travel time, access time, fee and income.It was found that demand and income elasticities were -0,10 and -0,32for on-street and private parking lot, respectively. Those elasticitiesexperienced a 33,5 % change when users’ income variations are considered.This shows that a restrictive parking management policy wouldaffect lower income groups.El presente artículo analiza la elasticidad de la demanda de estacionamientosobre la vía pública y en parqueadero privado en la zona céntricade la ciudad de Montería, Colombia, considerando variaciones en latarifa y en el nivel de ingreso de los usuarios.Los modelos fueron estimados con base en datos de preferencias declaradas.Las elasticidades fueron analizadas con un modelo de tipo logitmultinomial, cuyas variables explicativas fueron el tiempo de viaje, eltiempo de acceso, el costo y el ingreso.Se encontró que las elasticidades entre la demanda y la tarifa fueronde -0,10 y -0,32 para parqueo sobre la vía pública y en parqueaderoprivado, respectivamente. Se evidenció además una diferencia del33,5 % en el valor de dichas elasticidades cuando son consideradasvariaciones de ingreso de los individuos. Esto muestra que una políticarestrictiva de gestión de precios de parqueo afectaría más a grupos conmenores ingresos
Influence of survey engagement and multiple-choice heuristics in the estimation of the value of a statistical life
Estimating the value of non-market goods, such as reductions in mortality risks due to traffic accidents or air pollution, is typically done using stated choice (SC) data. However, issues with potential estimation biases due to the hypothetical nature of SC experiments arise, as protest choices are common and survey engagement is not constant across respondents. Further, if respondents choose to use different choice mechanisms and this is not considered, the results may also be biased. We designed an SC experiment to estimate the willingness to pay (WTP) for mortality risk reductions, that allowed us to simultaneously estimate the WTP to reduce the risk of traffic accident deaths and cardiorespiratory deaths due to air pollution. We formulated and estimated a multiple heuristic latent class model that also considered two latent constructs: Institutional Belief, to consider protest responses, and survey Engagement as a class membership covariate. We found, first, that individuals with lower institutional belief gave a higher probability of choice to the status-quo alternative, shying away from programs involving governmental action. Second, that not identifying respondents who do not appropriately engage in the experiment, biased the WTP estimators. In our case WTP decreased up to 26% when two different choice heuristics were allowed for in the model. © 202
Fundamentals and Applications of Surface-Enhanced Raman Spectroscopy (SERS)
When a molecule is adsorbed on some metallic nanostructured surfaces such as silver, copper or gold, it can undergo an enormous enhancement of the Raman signal giving rise to the so called Surface-Enhanced Raman Scattering (SERS). The high sensitivity of this effect allows an accurate structural study of adsorbates at very low concentrations. The SERS effect has historically been associated with the substrate roughness on two characteristic length scales. Surface roughness on the 10 to 100 nm length scale supports localized plasmon resonances which are considered as the dominant enhancement mechanism of SERS (Electromagnetic Enhancement Mechanism: SERS-EM). It is usually accepted that these electromagnetic resonances can increase the scattered intensity by an average factor of ca. 104 to 107. A secondary mechanism often thought to require atomic scale roughness is referred to as Charge Transfer (CT) Enhancement Mechanism (SERS-CT). This mechanism involves the photoinduced transfer of an electron from the metal to the adsorbate or vice versa and involves new electronic excited CT states which result from adsorbate–substrate chemical interactions. It is also estimated that such SERS-CT mechanism can enhance the scattering cross-section by a factor of ca. 10 to 102. These two mechanisms can operate simultaneously, depending on the particular systems and experimental conditions, making difficult to recognize each one and to estimate their relative magnitude in a particular spectrum.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
Microalgal peloids for cosmetic and wellness uses
Peloids have been used for therapeutic purposes since time immemorial, mainly in the treatment of locomotor system pathologies and dermatology. Their effects are attributed to their components, i.e., to the properties and action of mineral waters, clays, and their biological fraction, which may be made up of microalgae, cyanobacteria, and other organisms present in water and clays. There are many studies on the therapeutic use of peloids made with microalgae/cyanobacteria, but very little research has been done on dermocosmetic applications. Such research demonstrates their potential as soothing, regenerating, antioxidant, anti-inflammatory, and antimicrobial agents. In this work, a method for the manufacture of a dermocosmetic peloid is presented based on the experience of the authors and existing publications, with indications for its characterization and study of its efficacy
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