Travel Time Savings Perception and Well-Being through Public Transport Projects: The Case of Metro de Santiago

Relying mostly on travel time savings, cost-benefit analysis has been widely used in transport project appraisals in the Chilean context, with utility maximisation theory as its background. Nevertheless, subjective well-being advocates have challenged the notion of the rational man underlying this theory by proposing that other trip attributes, individual perceptions and personal features mediate satisfaction with travel, alongside global well-being. Using the recently-opened Line 6 of Metro de Santiago (Chile) as a case study, this research has two main aims: (1) to verify to what extent travel time savings, which support the cost-benefit analysis process, are present after the launching of the new line; and (2) analyse the perception of passengers’ travel time savings, and to what extent this element contributes to the travel satisfaction and to the global well-being at the individual level. Using passive data from smart cards, the results show that travel times decreased by 14% in comparable trips after the launching of Line 6. Furthermore, a confirmatory factor analysis (CFA) construct is proposed, including travel and life satisfaction as latent variables of the model. This revealed that travel times in the Metro system are highly valued by people. However, this element does not mediate travel satisfaction, as users take low travel times for granted. Waiting times, stations’ design, safety and intermodality are perceived attributes that effectively mediate travel satisfaction. Moreover, the latter variable has a relevant influence on global life satisfaction, revealing that transport conditions mediate in day-to-day well-being. These results challenged travel time savings as the most important driver in transport projects’ appraisal processes, and some recommendations are made in order to incorporate these findings in future appraisals

The Morphology of Type Ia Supernovae Light Curves

We present a family of six BVI template light curves for SNe Ia for days -5 and +80, based on high-quality data gathered at CTIO. These templates display a wide range of light curve morphologies, with initial decline rates of their B light curves between m15(B)=0.87 mag and 1.93 mag. We use these templates to study the general morphology of SNe Ia light curves. We find that several of the main features of the BVI templates correlate tightly with m15(B). In particular, the V light curves, which are probably a reasonably good approximation of the bolometric light curves, display an orderly progression in shapes between the most-luminous, slowest-declining events and the least-luminous, fastest-declining SNe. This supports the idea that the observed spectroscopic and photometric sequences of SNe Ia are due primarily to one parameter. Nevertheless, SNe with very similar initial decline rates do show significant differences in their light curve properties when examined in detail, suggesting the influence of one or more secondary parameters.Comment: 32 pages, 15 figures, to appear in the Astronomical Journa

“I drive outside of peak time to avoid traffic jams—Public transport is not attractive here.” Challenging discourses on travel to the University campus in Manila

One of the major narratives in transport policy internationally concerns the promotion of private versus public modes. The Global North has many examples where public transport, walking and cycling networks are well developed, yet examples from the Global South are less evident. There is a historical failure of replicating policies and practices from the Global North, particularly in perpetuating the highway building model, often unsuitable to the cultural contexts in the Global South. This paper examines individual attitudes and discourses concerning travel to De La Salle University campus, in Metro Manila, the Philippines. 42 participants are surveyed using Q methodology. Four discourses are developed, reflecting attitudes to growing automobility in Manila, public transport service provision, the difficulties of travelling in the city and the aspiration for increased comfort whilst travelling. Manila provides an example of the complexities in moving towards greater sustainable travel in the southeast Asian context where levels of private car usage are already high. It is hoped that a greater awareness of the problems of the current travel experiences might lead to us to seek different narratives, where transport systems can be developed which better serve social equity and environmental goals

Active probing of the mechanical properties of biological and synthetic vesicles

BACKGROUND: The interest in mechanics of synthetic and biological vesicles has been continuously growing during the last decades. Liposomes serve as model systems for investigating fundamental membrane processes and properties. More recently, extracellular vesicles (EVs) have been investigated mechanically as well. EVs are widely studied in fundamental and applied sciences, but their material properties remained elusive until recently. Elucidating the mechanical properties of vesicles is essential to unveil the mechanisms behind a variety of biological processes, e.g. budding, vesiculation and cellular uptake mechanisms. SCOPE OF REVIEW: The importance of mechanobiology for studies of vesicles and membranes is discussed, as well as the different available techniques to probe their mechanical properties. In particular, the mechanics of vesicles and membranes as obtained by nanoindentation, micropipette aspiration, optical tweezers, electrodeformation and electroporation experiments is addressed. MAJOR CONCLUSIONS: EVs and liposomes possess an astonishing rich, diverse behavior. To better understand their properties, and for optimization of their applications in nanotechnology, an improved understanding of their mechanical properties is needed. Depending on the size of the vesicles and the specific scientific question, different techniques can be chosen for their mechanical characterization. GENERAL SIGNIFICANCE: Understanding the mechanical properties of vesicles is necessary to gain deeper insight in the fundamental biological mechanisms involved in vesicle generation and cellular uptake. This furthermore facilitates technological applications such as using vesicles as targeted drug delivery vehicles. Liposome studies provide insight into fundamental membrane processes and properties, whereas the role and functioning of EVs in biology and medicine is increasingly elucidated

The Optical - Infrared Colors of CORALS QSOs: Searching for Dust Reddening Associated With High Redshift Damped Lyman Alpha Systems

The presence of dust in quasar absorbers, such as damped Lyman alpha (DLA) systems, may cause the background QSO to appear reddened. We investigate the extent of this potential reddening by comparing the optical-to-infrared (IR) colors of QSOs with and without intervening absorbers. Our QSO sample is based on the Complete Optical and Radio Absorption Line System (CORALS) survey of Ellison et al (2001). We have obtained near-simultaneous B and K band magnitudes for subset of the CORALS sample and supplemented our observations with further measurements published in the literature. To account for redshift-related color changes, the B-K colors are normalized using the Sloan Digital Sky Survey (SDSS) QSO composite. The mean normalized B-K color of the DLA sub-sample is +0.12, whereas the mean for the no-DLA sample is -0.10; both distributions have RMS scatters ~0.5. Neither a student's T-test nor a KS test indicate that there is any significant difference between the two color distributions. Based on simulations which redden the colors of QSOs with intervening DLAs, we determine a reddening limit which corresponds to E(B-V) < 0.04 (SMC-like extinction) at 99% confidence (3 sigma), assuming that E(B-V) is the same for all DLAs. Finally, we do not find any general correlation between absorber properties (such as [Fe/Zn] or neutral hydrogen column density) and B-K color. One of these two QSOs shows evidence for strong associated absorption from X-ray observations, an alternative explanation for its very red color. We conclude that the presence of intervening galaxies causes a minimal reddening of the background QSO.Comment: Accepted for publication in A

REMOCIÓN DE CADMIO MEDIANTE ADSORBENTES CERÁMICOS EMPACADOS EN COLUMNAS DE LECHO FIJO

The removal of cadmium ions (Cd2+) was evaluated from an aqueous solution on WhiteCancun and Red Tezontle quarry, using a fraction &gt;2000 ?m, at 23 °C under dynamicconditions in a packed bed. The percentage of cadmium extraction was studied throughadsorption kinetics, and with this the total adsorption capacity and the shelf life of thesorption column were calculated. A volumetric flow rate of 0.3 ml s-1 and an initialconcentration of 861.75 mg L-1 were used, and an initial concentration of 83.2mg L-1, at pH of 7.5. The White Cancun quarry reports a maximum extractionpercentage (% E) of 99.59 at the first minute of contact, compared to the tezontlethat reports %E&gt;83.78 at the same time. However, the total adsorption capacitywas 3.60 mg and 6.62 mg, respectively. The period of service life of the columnsuggests using tezontle as adsorbent.Se evaluó la remoción de iones de cadmio (Cd2+) a partir de una disolución acuosa sobre cantera Blanco Cancún y Tezontle rojo, utilizando una fracción &gt;2000 ?m, a 23 °C bajo condiciones dinámicas en un lecho empacado. Se investigó el porcentaje de extracción de cadmio mediante cinéticas de adsorción, y con ello se calculó la capacidad de adsorción total y el tiempo de vida útil de la columna de sorción. Se utilizó un flujo volumétrico de 0.3 ml s-1 y una concentración inicial de 861.75 mg L-1, a un pH de 7.5. La cantera Blanco Cancún reporta un porcentaje máximo de extracción (%E) de 99.59 al primer minuto de contacto, en comparación con el tezontle que reporta %E=83.78 al mismo tiempo. Sin embargo, la capacidad de adsorción total fue de 3.60 mg y 6.62 mg respectivamente. El tiempo de vida útil de la columna sugiereusar al tezontle como adsorbente