1,828 research outputs found
Photon localization barrier can be overcome
In contradistinction to a widespread belief that the spatial localization of
photons is restricted by a power-law falloff of the photon energy density,
I.Bialynicki-Birula [Phys. Rev. Lett. 80, 5247 (1998)] has proved that any
stronger -- up to an almost exponential -- falloff is allowed. We are showing
that for certain specifically designed cylindrical one-photon states the
localization is even better in lateral directions. If the photon state is built
from the so-called focus wave mode, the falloff in the waist cross-section
plane turns out to be quadratically exponential (Gaussian) and such strong
localization persists in the course of propagation.Comment: Short communication -- 4 pages, 2 figure
Directional characteristics of lunar thermal emission
Directional characteristics and brightness temperatures of thermal lunar emissio
The impacts of petroleum price fluctuations on income distribution across ethnic groups in Malaysia
Crude oil price hikes have compelled governments of developing countries to let domestic prices of energy increase. Fiscal priorities made it impossible to fully compensate the hikes by raising energy subsidies. This paper examines the potential impacts of a limited deregulation of the petroleum price on the income distribution in Malaysia, paying specific attention to differences in impacts on major ethnic groups. We introduce an extended social accounting matrix (SAM) model, which not only incorporates substitution possibilities among production inputs and consumption goods, but also allows for the exogenous determination of the price of intermediate inputs. The results of simulations indicate that distributional impacts of rising petroleum prices tend to be regressive, affecting poor people more severely than richer people. All ethnic groups experience income loss with the real incomes of Malay households (which are relatively poor, on average) more than the Chinese and Indian households (which are the generally richer)
Altitude-wind-tunnel Investigation of Performance Characteristics of a J47d Prototype (RX1-1) Turbojet Engine with Fixed-area Exhaust Nozzle
Modeling and kinetic determination in affinity precipitation of trypsin
A mathematical model was proposed to allow the analysis of kinetic enzyme in experimental of affinity precipitation system. The methodology was tested using a system composed of enzyme, ethylene glycol and conjugated PABA-poly (NIPAM).
N-isopropylacrylamide (NIPAM) is one of the monomers that have appealed to a great deal of investigation in the recent years. Its homopolymer NIPAM possesses temperature sensitivity and can act as a functional polymer with great potential. A water soluble ligand bound polymer has been synthesized by Electron Beam Irradiation for the purpose of affinity precipitation of trypsin. The affinity polymer
was formed by ligand-PABA. The binding efficiency of trypsin to this polymer was dependent upon the ratio of (NIPAM), mercaptopropionic acid (MPA) as a chain transfer reagent and p-aminobenzamidine (PABA) as ligand that used in the polymer synthesis. The amount of precipitated of poly (NIPAM) present in the polymer solution also greatly affected the trypsin binding efficiency. The total binding
capacity of trypsin molecules to ligand molecules approached the theoretical value which was considerably higher than that of insoluble gel matrices. Bound trypsin
could be easily eluted by the ethylene glycol solution. At low molecular weight of poly (NIPAM), the conjugate polymer solution was very stable and retained its high capacity for trypsin recovery over a long period of time. The proposed analysis and simulation of kinetic parameters may be helpful in affinity precipitation technique for advanced application
Symmetry, bifurcation and stacking of the central configurations of the planar 1+4 body problem
In this work we are interested in the central configurations of the planar
1+4 body problem where the satellites have different infinitesimal masses and
two of them are diametrically opposite in a circle. We can think this problem
as a stacked central configuration too. We show that the configuration are
necessarily symmetric and the other sattelites has the same mass. Moreover we
proved that the number of central configuration in this case is in general one,
two or three and in the special case where the satellites diametrically
opposite have the same mass we proved that the number of central configuration
is one or two saying the exact value of the ratio of the masses that provides
this bifurcation.Comment: 9 pages, 2 figures. arXiv admin note: text overlap with
arXiv:1103.627
Air quality resolution for health impact assessment: influence of regional characteristics
We evaluate how regional characteristics of population and background pollution might impact the selection of optimal air quality model resolution when calculating the human health impacts of changes to air quality. Using an approach consistent with air quality policy evaluation, we use a regional chemical transport model (CAMx) and a health benefit mapping program (BenMAP) to calculate the human health impacts associated with changes in ozone and fine particulate matter resulting from an emission reduction scenario. We evaluate this same scenario at 36, 12 and 4 km resolution for nine regions in the eastern US representing varied characteristics. We find that the human health benefits associated with changes in ozone concentrations are sensitive to resolution. This finding is especially strong in urban areas where we estimate that benefits calculated using coarse resolution results are on average two times greater than benefits calculated using finer scale results. In three urban areas we analyzed, results calculated using 36 km resolution modeling fell outside the uncertainty range of results calculated using finer scale modeling. In rural areas the influence of resolution is less pronounced with only an 8% increase in the estimated health impacts when using 36 km resolution over finer scales. In contrast, health benefits associated with changes in PM[subscript 2.5] concentrations were not sensitive to resolution and did not follow a pattern based on any regional characteristics evaluated. The largest difference between the health impacts estimated using 36 km modeling results and either 12 or 4 km results was at most ±10% in any region. Several regions showed increases in estimated benefits as resolution increased (opposite the impact seen with ozone modeling), while some regions showed decreases in estimated benefits as resolution increased. In both cases, the dominant contribution was from secondary PM. Additionally, we found that the health impacts calculated using several individual concentration–response functions varied by a larger amount than the impacts calculated using results modeled at different resolutions. Given that changes in PM[subscript 2.5] dominate the human health impacts, and given the uncertainty associated with human health response to changes in air pollution, we conclude that, when estimating the human health benefits associated with decreases in ozone and PM[subscript 2.5] together, the benefits calculated at 36 km resolution agree, within errors, with the benefits calculated using fine (12 km or finer) resolution modeling when using the current methodology for assessing policy decisions.United States. Environmental Protection Agency. Science to Achieve Results Program (Grant R834279)MIT Energy Initiative (Total Energy Fellowship)United States. Dept. of Energy. Office of Science (Grant DE-FG02-94ER61937)Massachusetts Institute of Technology. Joint Program on the Science & Policy of Global Chang
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