City Beautiful

The city beautiful movement, which in the early 20th Century advocated city beautification as a way to improve the living conditions and civic virtues of the urban dweller, had languished by the Great Depression. Today, new urban economic theory and policymakers are coming to see the provision of consumer leisure amenities as a way to attract population, especially the highly skilled and their employers. However, past studies have only provided indirect evidence of the importance of leisure amenities for urban development. In this paper we propose and validate the number of leisure trips to MSAs as a measure of consumer revealed preferences for local leisure-oriented amenities. Population and employment growth in the 1990s was about 2 percent higher in an MSA with twice as many leisure visits: the third most important predictor of recent population growth in standardized terms. Moreover, this variable does a good job at forecasting out-of-sample growth for the period 2000–2006. "Beautiful cities" disproportionally attracted highly-educated individuals, and experienced faster housing price appreciation, especially in supply-inelastic markets. Investment by local government in new public recreational areas within an MSA was positively associated with higher subsequent city attractiveness. In contrast to the generally declining trends in the American central city, neighborhoods that were close to "central recreational districts" have experienced economic growth, albeit at the cost of minority displacement.internal migration, amenities, urban population growth

City Beautiful

The City Beautiful movement, which in the early 20th century advocated city beautification as a way to improve the living conditions and civic virtues of the urban dweller, had languished by the Great Depression. Today, new urban economic theorists and policymakers are coming to see the provision of consumer leisure amenities as a way to attract population, especially the highly skilled and their employers. However, past studies have provided only indirect evidence of the importance of leisure amenities for urban development. In this paper we propose and validate the number of leisure trips to metropolitan statistical areas (MSAs) as a measure of consumers' revealed preferences for local leisure-oriented amenities. Population and employment growth in the 1990s was about 2 percent higher in an MSA with twice as many leisure visits: the third most important predictor of recent population growth in standardized terms. Moreover, this variable does a good job of forecasting out-of-sample growth for the period 2000-2006. “Beautiful cities” disproportionally attracted highly educated individuals and experienced faster housing price appreciation, especially in supply-inelastic markets. Investment by local government in new public recreational areas within an MSA was positively associated with higher subsequent city attractiveness. In contrast to the generally declining trends in the American central city, neighborhoods that were close to “central recreational districts” have experienced economic growth, albeit at the cost of minority displacement.Cities and towns

The AliEn system, status and perspectives

AliEn is a production environment that implements several components of the Grid paradigm needed to simulate, reconstruct and analyse HEP data in a distributed way. The system is built around Open Source components, uses the Web Services model and standard network protocols to implement the computing platform that is currently being used to produce and analyse Monte Carlo data at over 30 sites on four continents. The aim of this paper is to present the current AliEn architecture and outline its future developments in the light of emerging standards.Comment: Talk from the 2003 Computing in High Energy and Nuclear Physics (CHEP03), La Jolla, Ca, USA, March 2003, 10 pages, Word, 10 figures. PSN MOAT00

Redefining the boundaries of interplanetary coronal mass ejections from observations at the ecliptic plane

On 2015 January 6-7, an interplanetary coronal mass ejection (ICME) was observed at L1. This event, which can be associated with a weak and slow coronal mass ejection, allows us to discuss on the differences between the boundaries of the magnetic cloud and the compositional boundaries. A fast stream from a solar coronal hole surrounding this ICME offers a unique opportunity to check the boundaries' process definition and to explain differences between them. Using Wind and ACE data, we perform a complementary analysis involving compositional, magnetic, and kinematic observations providing relevant information regarding the evolution of the ICME as travelling away from the Sun. We propose erosion, at least at the front boundary of the ICME, as the main reason for the difference between the boundaries, and compositional signatures as the most precise diagnostic tool for the boundaries of ICMEs.Comment: 9 pages and 7 figures in the original forma

A Carrington-like geomagnetic storm observed in the 21st century

In September 1859 the Colaba observatory measured the most extreme geomagnetic disturbance ever recorded at low latitudes related to solar activity: the Carrington storm. This paper describes a geomagnetic disturbance case with a profile extraordinarily similar to the disturbance of the Carrington event at Colaba: the event on 29 October 2003 at Tihany magnetic observatory in Hungary. The analysis of the H-field at different locations during the "Carrington-like" event leads to a re-interpretation of the 1859 event. The major conclusions of the paper are the following: (a) the global Dst or SYM-H, as indices based on averaging, missed the largest geomagnetic disturbance in the 29 October 2003 event and might have missed the 1859 disturbance, since the large spike in the horizontal component (H) of terrestrial magnetic field depends strongly on magnetic local time (MLT); (b) the main cause of the large drop in H recorded at Colaba during the Carrington storm was not the ring current but field-aligned currents (FACs), and (c) the very local signatures of the H-spike imply that a Carrington-like event can occur more often than expected.Comment: 18 pages, 2 figures, accepted for publication in SWS

Enhancing thermoelectric properties of graphene quantum rings

We study the thermoelectric properties of rectangular graphene rings connected symmetrically or asymmetrically to the leads. A side-gate voltage applied across the ring allows for the precise control of the electric current flowing through the system. The transmission coefficient of the rings manifests Breit-Wigner line-shapes and/or Fano line-shapes, depending on the connection configuration, the width of nanoribbons forming the ring and the side-gate voltage. We find that the thermopower and the figure of merit are greatly enhanced when the chemical potential is tuned close to resonances. Such enhancement is even more pronounced in the vicinity of Fano like anti-resonances which can be induced by a side-gate voltage independently of the geometry. This opens a possibility to use the proposed device as a tunable thermoelectric generator.Comment: 6 pages, 5 figures, accepted for publication in Physical Review

Supergranular-scale magnetic flux emergence beneath an unstable filament

Here we report evidence of a large solar filament eruption on 2013, September 29. This smooth eruption, which passed without any previous flare, formed after a two-ribbon flare and a coronal mass ejection towards Earth. The coronal mass ejection generated a moderate geomagnetic storm on 2013, October 2 with very serious localized effects. The whole event passed unnoticed to flare-warning systems. We have conducted multi-wavelength analyses of the Solar Dynamics Observatory through Atmospheric Imaging Assembly (AIA) and Helioseismic and Magnetic Imager (HMI) data. The AIA data on 304, 193, 211, and 94 \AA sample the transition region and the corona, respectively, while HMI provides photospheric magnetograms, continuum, and linear polarization data, in addition to the fully inverted data provided by HMI. [...] We have observed a supergranular-sized emergence close to a large filament in the boundary of the active region NOAA11850. Filament dynamics and magnetogram results suggest that the magnetic flux emergence takes place in the photospheric level below the filament. Reconnection occurs underneath the filament between the dipped lines that support the filament and the supergranular emergence. The very smooth ascent is probably caused by this emergence and torus instability may play a fundamental role, which is helped by the emergence.Comment: 9 pages, 6 figures, online material at Journa