2,207 research outputs found
On the Measurement of “Grayness” of Cities
We consider a situation where individuals belonging to multiple groups inhabit a space that can be divided into smaller distinguishable units, a feature characterizing many cities in the world. When data on an economic attribute (in our case, income) is available, we conceptualize a phenomenon that we refer to as “Grayness” - a combination of spatial integration based upon group-identity and income. Grayness is high when cities display a high degree of spatial co-existence in terms of both identity and income. We lay down some desirable properties of a measure of Grayness and develop a simple and intuitive index that satisfies them. We provide an illustration by using data from the Indian city of Hyderabad, and selected American cities
A SYSTEM FOR THE EVALUATION OF ON-WATER STROKE FORCE DEVELOPMENT DURING CANOE AND KAYAK EVENTS
Sport practitioners, including coaches and athletes of a wide variety of sport disciplines, are becoming more and more aware of the value of recording and analysing the real time data correlates of the force output of the athlete under competitive conditions. In no other comparable onwater sport is the relationship between absolute force development and the manner of its production and application more critical to the final outcome of the event than in flatwater canoe and kayak, particularly in multiple athlete events (Plagenhoef, 1979; Mann and Kearney, 1980)
Integrated spatial multiplexing of heralded single photon sources
The non-deterministic nature of photon sources is a key limitation for single
photon quantum processors. Spatial multiplexing overcomes this by enhancing the
heralded single photon yield without enhancing the output noise. Here the
intrinsic statistical limit of an individual source is surpassed by spatially
multiplexing two monolithic silicon correlated photon pair sources,
demonstrating a 62.4% increase in the heralded single photon output without an
increase in unwanted multi-pair generation. We further demonstrate the
scalability of this scheme by multiplexing photons generated in two waveguides
pumped via an integrated coupler with a 63.1% increase in the heralded photon
rate. This demonstration paves the way for a scalable architecture for
multiplexing many photon sources in a compact integrated platform and achieving
efficient two photon interference, required at the core of optical quantum
computing and quantum communication protocols.Comment: 10 pages, 3 figures, comments welcom
POEMMA: Probe Of Extreme Multi-Messenger Astrophysics
The Probe Of Extreme Multi-Messenger Astrophysics (POEMMA) mission is being
designed to establish charged-particle astronomy with ultra-high energy cosmic
rays (UHECRs) and to observe cosmogenic tau neutrinos (CTNs). The study of
UHECRs and CTNs from space will yield orders-of-magnitude increase in
statistics of observed UHECRs at the highest energies, and the observation of
the cosmogenic flux of neutrinos for a range of UHECR models. These
observations should solve the long-standing puzzle of the origin of the highest
energy particles ever observed, providing a new window onto the most energetic
environments and events in the Universe, while studying particle interactions
well beyond accelerator energies. The discovery of CTNs will help solve the
puzzle of the origin of UHECRs and begin a new field of Astroparticle Physics
with the study of neutrino properties at ultra-high energies.Comment: 8 pages, in the Proceedings of the 35th International Cosmic Ray
Conference, ICRC217, Busan, Kore
Exploring the biochemistry at the extracellular redox frontier of bacterial mineral Fe(III) respiration
Many species of the bacterial Shewanella genus are notable for their ability to respire in anoxic environments utilizing insoluble minerals of Fe(III) and Mn(IV) as extracellular electron acceptors. In Shewanella oneidensis, the process is dependent on the decahaem electron-transport proteins that lie at the extracellular face of the outer membrane where they can contact the insoluble mineral substrates. These extracellular proteins are charged with electrons provided by an inter-membrane electron-transfer pathway that links the extracellular face of the outer membrane with the inner cytoplasmic membrane and thereby intracellular electron sources. In the present paper, we consider the common structural features of two of these outer-membrane decahaem cytochromes, MtrC and MtrF, and bring this together with biochemical, spectroscopic and voltammetric data to identify common and distinct properties of these prototypical members of different clades of the outer-membrane decahaem cytochrome superfamily
Challenges for Creating and Sustaining A Green Revolution in Africa
Research and Development/Tech Change/Emerging Technologies,
Diversification and agrarian change under environmental constraints in rural China: Evidence from a poor township of Beijing municipality
Working paper du GATE 2007-11This article illustrates the impact of changes related to market reforms and environmental policies on the economic structure in rural China by providing a comparative analysis of several villages in a poor township in Beijing municipality. Two main concomitant phenomena are affecting agricultural and non-agricultural choices in the studied area. First, the introduction of market mechanisms is encouraging local population to engage in new activities that are closer to local comparative advantages. Second, rural households are facing new constraints in the form of environmental protection measures, which have weakened traditional insurance channels provided by forest resources and cattle stock. Drawing on household-level survey data and interviews with village heads conducted in ten villages of Labagoumen township in December 2003, this article analyzes households decisions in response to market reforms and environmental constraints. We find large disparities both between villages and households in the diversification process and discuss the reasons of observed inertia in the region, most households still heavily relying on corn production
High cadence spectropolarimetry of moving magnetic features observed around a pore
Moving magnetic features (MMFs) are small-size magnetic elements that are
seen to stream out from sunspots, generally during their decay phase. Several
observational results presented in the literature suggest them to be closely
related to magnetic filaments that extend from the penumbra of the parent spot.
Nevertheless, few observations of MMFs streaming out from spots without
penumbra have been reported. The literature still lacks of analyses of the
physical properties of these features.
We investigate physical properties of monopolar MMFs observed around a small
pore that had developed penumbra in the days preceding our observations and
compare our results with those reported in the literature for features observed
around sunspots. We analyzed NOAA 11005 during its decay phase with data
acquired at the Dunn Solar Telescope in the FeI 617.3
nm spectral lines with IBIS, and in the G-band. The field of view showed
monopolar MMFs of both polarities streaming out from the leading negative
polarity pore of the observed active region. Combining different analyses of
the data, we investigated the temporal evolution of the relevant physical
quantities associated with the MMFs as well as the photospheric and
chromospheric signatures of these features.
We show that the characteristics of the investigated MMFs agree with those
reported in the literature for MMFs that stream out from spots with penumbrae.
Moreover, observations of at least two of the observed features suggest them to
be manifestations of emerging magnetic arches.Comment: Accepted by A&
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