36,233 research outputs found
Mobility on Demand in the United States
The growth of shared mobility services and enabling technologies, such as smartphone apps, is contributing to the commodification and aggregation of transportation services. This chapter reviews terms and definitions related to Mobility on Demand (MOD) and Mobility as a Service (MaaS), the mobility marketplace, stakeholders, and enablers. This chapter also reviews the U.S. Department of Transportation’s MOD Sandbox Program, including common opportunities and challenges, partnerships, and case studies for employing on-demand mobility pilots and programs. The chapter concludes with a discussion of vehicle automation and on-demand mobility including pilot projects and the potential transformative impacts of shared automated vehicles on parking, land use, and the built environment
X-ray and optical observations of three clusters of galaxies: Abell 901, Abell 1437, and Abell 3570
We analyse three clusters of galaxies, Abell 901 (z=0.17), Abell 1437
(z=0.13) and Abell 3570 (z=0.037). They have low to intermediate X-ray fluxes
and an irregular morphology in the ROSAT All-Sky Survey (RASS). These clusters
are chosen to test the abilities and limitations of the RASS in terms of
cluster fluxes and cluster morphologies. Therefore some ``worst'' cases are
used here. X-ray observations with the ROSAT/HRI and optical spectroscopic
observations are carried out. The ROSAT/HRI observations, which have a much
better spatial resolution than the RASS, reveal in two of the three cases a
significantly different morphology than seen in the RASS. The reasons are point
sources which could not be resolved in the RASS and were therefore confused
with the cluster emission. For A3570 we could confirm the relaxed state of the
cluster by the optical determination of a small velocity dispersion. In the
cluster with the lowest flux (Abell 901) the countrate measurement is strongly
affected by point sources, in the two other cases the countrate measurements of
the RASS are reliable, i.e. they are reproduced by the ROSAT/HRI measurement.
We conclude that for clusters with a flux of a few times 10^{-12} erg/cm^2/s or
smaller, which show at the same time a non-relaxed morphology, the flux
measurement of the RASS can be seriously affected by fore- or background
sources. We point out that an all-sky survey of a second ABRIXAS mission would
provide a much clearer source distinction for low-flux clusters and thus a much
improved countrate determination.Comment: 8 pages (incl. 6 figures), accepted for publication in A&A (Suppl.
Globalisation, labour markets and international adjustment - Essays in honour of Palle S Andersen
Pre-participation Cardiac Screening in Young Athletes: Models and Criteria
This is the second of two review articles focusing on the value of preparticipation
cardiac screening in young athletes. The article focuses on the efficacy of the resting 12-lead electrocardiogram (ECG), physical examination, and medical history questionnaire, which commonly make up the first stage of a cardiac screening protocol.
The review then focuses on specific structural and electrical abnormalities which are responsible for sudden cardiac death (SCD) in young athletes – the most common of which is hypertrophic cardiomyopathy. The identification of appropriate ‘red flag’ signs and symptoms is essential for teasing out potential pathological conditions
and allowing differentiation from often benign physiological adaptations. The final section provides guidance on how the resting 12-lead ECG can be used to separate pathological from physiological adaptations in young athletes
Foreign exchange market intervention in emerging markets: motives, techniques and implications
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