3,310 research outputs found
Massive creation of entangled exciton states in semiconductor quantum dots
An intense laser pulse propagating in a medium of inhomogeneously broadened
quantum dots massively creates entangled exciton states. After passage of the
pulse all single-exciton states remain unpopulated (self-induced transparency)
whereas biexciton coherence (exciton entanglement) is generated through
two-photon transitions. We propose several experimental techniques for the
observation of such unexpected behavior
The Effects of Deep Oscillation Therapy for Individuals with Lower-Leg Pain
Purpose: Lower extremity (LE) pain accounts for 13-20% of injuries in the active population. LE pain has been contributed to inflexibility and fascial restrictions. Deep oscillation therapy (DOT) has been proposed to improve range of motion and reduce pain following musculoskeletal injuries. Therefore, our objective was to determine the effectiveness of DOT on ankle dorsiflexion range of motion (ROM) and pain in individuals with and without lower-leg pain. Methods: We used a single blind, pre-post experimental study in a research laboratory. Thirty-two active participants completed this study. Sixteen individuals reporting lower-leg pain and sixteen non-painful individuals completed the study. Participants received a single session of DOT performed by one researcher to their affected limb or matched limb. The intervention parameters included a 1:1 mode and 70-80% dosage. The intervention began by stimulating the lymphatic channels at the cisterna chyli, the inguinal lymph node, and the popliteal lymph node at a frequency of 150 Hz all for a minute each. Next, the researcher treated the triceps surae complex for 11 minutes at three different frequencies. Finally, the participant was treated distal to the popliteal lymph node at 25 Hz for 5 minutes. The main outcome measures included pain using the VAS and ankle dorsiflexion ROM with the weight-bearing lunge test (WBLT). Statistical analyses included descriptive statistics and F-test comparisons between and within groups. Results: The average WBLT measures for all participants increased 0.6 cm, which not to the minimal detectable change for passive ankle dorsiflexion ROM. Significant differences from pre-post measures were identified for pain on the VAS. Conclusion: While increases in ROM were identified, the difference was not clinically important. DOT was successful in decreasing lower-leg pain
Experimental Verification of 3D Plasmonic Cloaking in Free-Space
We report the experimental verification of metamaterial cloaking for a 3D
object in free space. We apply the plasmonic cloaking technique, based on
scattering cancellation, to suppress microwave scattering from a finite-length
dielectric cylinder. We verify that scattering suppression is obtained all
around the object in the near- and far-field and for different incidence
angles, validating our measurements with analytical results and full-wave
simulations. Our near-field and far-field measurements confirm that realistic
and robust plasmonic metamaterial cloaks may be realized for elongated 3D
objects with moderate transverse cross-section at microwave frequencies.Comment: 12 pages, 8 figures, published in NJ
The Effects of Deep Oscillation Therapy for Individuals with Lower-Leg Pain
Purpose: Lower extremity (LE) pain accounts for 13-20% of injuries in the active population. LE pain has been contributed to inflexibility and fascial restrictions. Deep oscillation therapy (DOT) has been proposed to improve range of motion and reduce pain following musculoskeletal injuries. Therefore, our objective was to determine the effectiveness of DOT on ankle dorsiflexion range of motion (ROM) and pain in individuals with and without lower-leg pain. Methods: We used a single blind, pre-post experimental study in a research laboratory. Thirty-two active participants completed this study. Sixteen individuals reporting lower-leg pain and sixteen non-painful individuals completed the study. Participants received a single session of DOT performed by one researcher to their affected limb or matched limb. The intervention parameters included a 1:1 mode and 70-80% dosage. The intervention began by stimulating the lymphatic channels at the cisterna chyli, the inguinal lymph node, and the popliteal lymph node at a frequency of 150 Hz all for a minute each. Next, the researcher treated the triceps surae complex for 11 minutes at three different frequencies. Finally, the participant was treated distal to the popliteal lymph node at 25 Hz for 5 minutes. The main outcome measures included pain using the VAS and ankle dorsiflexion ROM with the weight-bearing lunge test (WBLT). Statistical analyses included descriptive statistics and F-test comparisons between and within groups. Results: The average WBLT measures for all participants increased 0.6 cm, which not to the minimal detectable change for passive ankle dorsiflexion ROM. Significant differences from pre-post measures were identified for pain on the VAS. Conclusion: While increases in ROM were identified, the difference was not clinically important. DOT was successful in decreasing lower-leg pain
A COMMUNITY-BASED VULNERABILITY ASSESSMENT OF FLOODS IN URBAN AREAS OF KAMPUNG MELAYU, JAKARTA
Flooding has become a serious problem in Jakarta. During floods .of 2007,
Kampung Melayu, East Jakarta was the worst hit.by the floods. Community have
different perceptions on disaster and have different effort to overcome the hazards.
Therefore, local government and relevant institution should investigate this
situation and make this information a valuable input in developing and
implementing response plans in flood mitigation. This research is to explore the
vulnerability of floods based on local people\u27s perception. There were 83
households interviewed using questionnaire. Certain elements at risk related with
physical and socio:economic aspects were identified. Physical information
concerned the building structure and building contents. Several socio-economic
characteristics were used as key indicators to analyze the vulnerability of people.
Generally, the result of this research shows that the ability of people to cope with
the flooding i$ linked with the capacity of the people itself. The capability of people
to deal withflooding was influenced by several indicators.based on their socio- .
economic characteristics. For example, lower income people will experience more
suffering than the wealthier, because they cannot afford the\u27 costs of repair,
reconstruction. Although the wealthier are likely to experience a higher degree of
economic damage due to possessions of higher value. Base on the analysis, all
coping strategies and flood measures are not enough to cope with flooding in the
study area
Observations of H3+ in the Diffuse Interstellar Medium
Surprisingly large column densities of H3+ have been detected using infrared
absorption spectroscopy in seven diffuse cloud sightlines (Cygnus OB2 12,
Cygnus OB2 5, HD 183143, HD 20041, WR 104, WR 118, and WR 121), demonstrating
that H3+ is ubiquitous in the diffuse interstellar medium. Using the standard
model of diffuse cloud chemistry, our H3+ column densities imply unreasonably
long path lengths (~1 kpc) and low densities (~3 cm^-3). Complimentary
millimeter-wave, infrared, and visible observations of related species suggest
that the chemical model is incorrect and that the number density of H3+ must be
increased by one to two orders of magnitude. Possible solutions include a
reduced electron fraction, an enhanced rate of H2 ionization, and/or a smaller
value of the H3+ dissociative recombination rate constant than implied by
laboratory experiments.Comment: To be published in Astrophysical Journal, March 200
The Radiated Energy Budget of Chromospheric Plasma in a Major Solar Flare Deduced From Multi-Wavelength Observations
This paper presents measurements of the energy radiated by the lower solar
atmosphere, at optical, UV, and EUV wavelengths, during an X-class solar flare
(SOL2011-02-15T01:56) in response to an injection of energy assumed to be in
the form of nonthermal electrons. Hard X-ray observations from RHESSI were used
to track the evolution of the parameters of the nonthermal electron
distribution to reveal the total power contained in flare accelerated
electrons. By integrating over the duration of the impulsive phase, the total
energy contained in the nonthermal electrons was found to be
erg. The response of the lower solar atmosphere was measured in the free-bound
EUV continua of H I (Lyman), He I, and He II, plus the emission lines of He II
at 304\AA\ and H I (Ly) at 1216\AA\ by SDO/EVE, the UV continua at
1600\AA\ and 1700\AA\ by SDO/AIA, and the WL continuum at 4504\AA, 5550\AA, and
6684\AA, along with the Ca II H line at 3968\AA\ using Hinode/SOT. The summed
energy detected by these instruments amounted to erg;
about 15% of the total nonthermal energy. The Ly line was found to
dominate the measured radiative losses. Parameters of both the driving electron
distribution and the resulting chromospheric response are presented in detail
to encourage the numerical modelling of flare heating for this event, to
determine the depth of the solar atmosphere at which these line and continuum
processes originate, and the mechanism(s) responsible for their generation.Comment: 14 pages, 18 figures. Accepted for publication in Astrophysics
Journa
Superconductivity in the Correlated Pyrochlore Cd_2Re_2O_7
We report the observation of superconductivity in high-quality
CdReO single crystals with room-temperature pyrochlore structure.
Resistivity and ac susceptibility measurements establish an onset transition
temperature T = 1.47 K with transition width T = 0.25
K. In applied magnetic field, the resistive transition shows a type-II
character, with an approximately linear temperature-dependence of the upper
critical field H. The bulk nature of the superconductivity is confirmed
by the specific heat jump with C = 37.9 mJ/mol-K. Using the
value extracted from normal-state specific heat data, we obtain
C/T = 1.29, close to the weak coupling BCS value. In the
normal state, a negative Hall coefficient below 100 K suggests electron-like
conduction in this material. The resistivity exhibits a quadratic T-dependence
between 2 and 60 K, i.e., +AT, indicative of Fermi-liquid
behavior. The values of the Kadowaki-Woods ratio A/ and the Wilson
ratio are comparable to that for strongly correlated materials.Comment: 4 pages, 5 figure
Isochronal annealing effects on local structure, crystalline fraction, and undamaged region size of radiation damage in Ga-stabilized -Pu
The effects on the local structure due to self-irradiation damage of Ga
stabilized -Pu stored at cryogenic temperatures have been examined
using extended x-ray absorption fine structure (EXAFS) experiments. Extensive
damage, seen as a loss of local order, was evident after 72 days of storage
below 15 K. The effect was observed from both the Pu and Ga sites, although
less pronounced around Ga. Isochronal annealing was performed on this sample to
study the annealing processes that occur between cryogenic and room temperature
storage conditions, where damage is mostly reversed. Damage fractions at
various points along the annealing curve have been determined using an
amplitude-ratio method, standard EXAFS fitting, and a spherical crystallite
model, and provide information complementary to previous electrical
resistivity- and susceptibility-based isochronal annealing studies. The use of
a spherical crystallite model accounts for the changes in EXAFS spectra using
just two parameters, namely, the crystalline fraction and the particle radius.
Together, these results are discussed in terms of changes to the local
structure around Ga and Pu throughout the annealing process and highlight the
unusual role of Ga in the behavior of the lowest temperature anneals.Comment: 13 pages, 10 figure
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