23,371 research outputs found
Rethinking mobility at the urban-transportation-geography nexus
Building on the main sections of the book, this concluding chapter identifies four thematic areas for future research into the urban-transportation-geography nexus as follows: (1) the everyday experience of transport and mobility in the “ordinary city”; (2) the environment and the urban politics of mobility; (3) connected cities and competitive states; and (4) transportation mobility and new imaginaries of city-regional development
Demixing light paths inside disordered metamaterials
We experimentally demonstrate the first method to focus light inside disordered photonic metamaterials. In such materials, scattering prevents light from forming a geometric focus. Instead of geometric optics, we used multi-path interference to make the scattering process itself concentrate light on a fluorescent nanoscale probe at the target position. Our method uses the fact that the disorder in a solid material is fixed in time. Therefore, even disordered light scattering is deterministic. Measurements of the probes fluorescence provided the information needed to construct a specific linear combination of hundreds of incident waves, which interfere constructively at the probe.\ud
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Gamma-ray emission expected from Kepler's SNR
Nonlinear kinetic theory of cosmic ray (CR) acceleration in supernova
remnants (SNRs) is used to investigate the properties of Kepler's SNR and, in
particular, to predict the gamma-ray spectrum expected from this SNR.
Observations of the nonthermal radio and X-ray emission spectra as well as
theoretical constraints for the total supernova (SN) explosion energy E_sn are
used to constrain the astronomical and particle acceleration parameters of the
system. Under the assumption that Kepler's SN is a type Ia SN we determine for
any given explosion energy E_sn and source distance d the mass density of the
ambient interstellar medium (ISM) from a fit to the observed SNR size and
expansion speed. This makes it possible to make predictions for the expected
gamma-ray flux. Exploring the expected distance range we find that for a
typical explosion energy E_sn=10^51 erg the expected energy flux of TeV
gamma-rays varies from 2x10^{-11} to 10^{-13} erg/(cm^2 s) when the distance
changes from d=3.4 kpc to 7 kpc. In all cases the gamma-ray emission is
dominated by \pi^0-decay gamma-rays due to nuclear CRs. Therefore Kepler's SNR
represents a very promising target for instruments like H.E.S.S., CANGAROO and
GLAST. A non-detection of gamma-rays would mean that the actual source distance
is larger than 7 kpc.Comment: 6 pages, 4 figures. Accepted for publication in Astronomy and
Astrophysics, minor typos correcte
An investigation of the interaction of N2O with the Si(111)-7 × 7 surface using AES and optical reflectometry; A comparison with O2
At 300 K, N2O decomposes into N2, leaving behind atomic oxygen at the Si(111)¿7 × 7 surface. Decomposition at two different sites is proposed, having the overall initial reaction probability: s(0) = (6.7 ± 0.7) × 106. SiOx(x not, vert, similar 1) bonds are predominantly formed, saturation occurring at monolayer coverage. This oxygen monolayer appears to completely prevent further oxygen uptake by additional N2O or O2 exposures, in contrast with the adsorption behaviour of O2 on Si(111)-7 × 7, which exhibits slow sorption beyond one monolayer
COUNTRY OWNERSHIP OF REFORM PROGRAMMES AND THE IMPLICATIONS FOR CONDITIONALITY
The essence of ownership is the acceptance of full responsibility for the consequences of a programme. Ownership matters because of the expectation that programme design will be more appropriate and country authorities will be resolute in taking steps domestically to ensure full implementation of the programme. The steps include seeking proper domestic legitimation, which will prevent certain "political economy" factors from disrupting programme implementation. That programme success is correlated with degree of ownership and that ownership is correlated with implementation, which in turn is correlated with programme legitimation, are supported by available evidence. Ex ante selectivity is easily made preferable to ex post, and for financial support a recipient country must satisfy the donor country or organization team as to the reality of ownership, soundness of the programme (policies and outcomes), and adequate implementation capacity. From a positive perspective, forces operating on both the demand and supply side of aid should inevitably bring about a new equilibrium regime in the aid relationship that excludes traditional conditionality.
Enhanced Optical Cooling of Ion Beams for LHC
The possibility of the enhanced optical cooling (EOC) of Lead ions in LHC is
investigated. Non-exponential feature of cooling and requirements to the ring
lattice, optical and laser systems are discussed. Comparison with optical
stochastic cooling (OSC) is represented.Comment: 4 page
The environmental effect of car-free housing: A case in Vienna
A case-control study of the car-free model housing project in Vienna was conducted to evaluate whether people living in this settlement have more [`]sustainable lifestyles' than people living in comparable buildings in Vienna. Another aim was to identify the lifestyle characteristics and household activities which significantly influence the environmental impact of the residents of the car-free housing project and a control group. The control group, referred to as the reference settlement, was chosen from a nearby building complex, with similar characteristics, but without the car-free feature. Household consumption patterns were estimated based on interviews in combination with data from the Austrian consumer expenditure survey and the national accounts. The evaluation of household environmental impacts uses emissions estimates from the Austrian national accounting matrices including environmental accounts and data from life-cycle assessments. Households from the car-free settlement have substantially lower environmental impacts in the categories of ground transportation and energy use; their CO2 emissions of these two categories are less than 50% of those living in the reference settlement. The households in the car-free settlement have somewhat higher emissions in the categories air transport, nutrition, and [`]other' consumption, reflecting the higher income per-capita. As a result, the CO2 emissions are only slightly lower than in the reference settlement, but the emissions intensity is 20% lower. Both household groups have significantly lower environmental impacts than the Austrian average reflecting less car use and cleaner heating energy in Vienna
A composite open resonator for compact X-ray source
The results of calculation of the finesse of a composite open resonator for
compact X-ray source are presented. The region of the resonator parameters has
been found where the finesse is changed unessentially.Comment: 2 pages, LaTe
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