5,832 research outputs found
How Will the Patient Protection and Affordable Care Act of 2010 Affect Young Adults?
Summarizes how healthcare reform provisions including the expansion of dependent coverage, subsidies for insurance premiums, and penalties for opting out of coverage will affect young adults ages 19-29 by income level and gender
Evolution of Magnetic and Superconducting Fluctuations with Doping of High-Tc Superconductors
Electronic Raman scattering from high- and low-energy excitations was studied
as a function of temperature, extent of hole doping, and energy of the incident
photons in Bi_2Sr_2CaCu_2O_{8 \pm \delta} superconductors. For underdoped
superconductors, short range antiferromagnetic (AF) correlations were found to
persist with hole doping, and doped single holes were found to be incoherent in
the AF environment. Above the superconducting (SC) transition temperature T_c,
the system exhibits a sharp Raman resonance of B_{1g} symmetry and energy of 75
meV and a pseudogap for electron-hole excitations below 75 meV, a manifestation
of a partially coherent state forming from doped incoherent quasi particles.
The occupancy of the coherent state increases with cooling until phase ordering
at T_c produces a global SC state.Comment: 6 pages, 4 color figures, PDF forma
\u3cem\u3eBacillus megaterium \u3c/em\u3eand \u3cem\u3ePapiliotrema laurentii: \u3c/em\u3eCompeting roles in polymer coating degradation?
The design of coating formulations that have material properties that can hinder the biodegradation of a protective surface without aggressive or environmentally harmful additives will require a detailed understanding of knowledge gaps at the biotic-abiotic interface involving a variety of microorganisms. This project focused on two isolates extracted from a biofilm which was found to degrade Air Force cargo aircraft topcoats. These organisms, Bacillus megaterium (gram-negative bacterium, non-hydrolytic but alkane oxidizing) and the hydrolytic yeast Papiliotrema laurentii were initially observed as individual cultures and then as a co-culture. The combination of these two organisms (under similar growth conditions) provided a glimpse into more complex biofilm dynamics and the synergies these organisms maintain during the degradation of polyester polyurethane and the more recalcitrant polyether polyurethane topcoat, AS P-108
Over the Counter Availability of Antituberculosis Drugs in Tbilisi, Georgia in the Setting of a High Prevalence of MDR-TB
Georgia, a country of 4.5 million people, has a high incidence of tuberculosis (TB) including drug resistant cases. Easy access and
inappropriate use of anti-TB drugs are risk factors for further development
of multidrug resistant (MDR)-TB. We carried out an investigation to assess
the availability of over the counter anti-TB agents in pharmacies in Tbilisi.
During February 2006, 15 pharmacies were randomly selected and the
pharmacist at each store was interviewed. We found that all anti-TB
medications stocked by these pharmacies were available and sold without
a prescription. All 15 pharmacies sold isoniazid, rifampicin, and
streptomycin; 13 (87%) of 15 pharmacies also sold pyrazinamide,
ethambutol. Second line anti-TB drugs such as amikacin and kanamycin
(injectable agents) and older fluoroquinolones (ofloxacin and ciprofloxacin)
were available at 13 pharmacies while newer generation fluoroquinolones
were less available(3 sold leovofloxacin, none sold moxifloxacin). The
ease access and availability of anti-TB agents is of a great concern given
the high prevalence of TB including MDR-TB in Georgia. The potential for
misuse of these anti-TB drugs can lead to the development of further drug
resistance. These drugs should only be available by prescription in order to
reduce the chance of amplifying drug resistance
Evolution of Superconductivity in Electron-Doped Cuprates: Magneto-Raman Spectroscopy
The electron-doped cuprates Pr_{2-x}Ce_xCuO_4 and Nd_{2-x}Ce_xCuO_4 have been
studied by electronic Raman spectroscopy across the entire region of the
superconducting (SC) phase diagram. The SC pairing strength is found to be
consistent with a weak-coupling regime except in the under-doped region where
we observe an in-gap collective mode at 4.5 k_{B}T_c while the maximum
amplitude of the SC gap is ~8 k_{B}T_{c}. In the normal state, doped carriers
divide into coherent quasi-particles (QPs) and carriers that remain incoherent.
The coherent QPs mainly reside in the vicinity of (\pi/2, \pi/2) regions of the
Brillouin zone (BZ). We find that only coherent QPs contribute to the
superfluid density in the B_{2g} channel. The persistence of SC coherence peaks
in the B_{2g} channel for all dopings implies that superconductivity is mainly
governed by interactions between the hole-like coherent QPs in the vicinity of
(\pi/2, \pi/2) regions of the BZ. We establish that superconductivity in the
electron-doped cuprates occurs primarily due to pairing and condensation of
hole-like carriers. We have also studied the excitations across the SC gap by
Raman spectroscopy as a function of temperature (T) and magnetic field (H) for
several different cerium dopings (x). Effective upper critical field lines
H*_{c2}(T, x) at which the superfluid stiffness vanishes and
H^{2\Delta}_{c2}(T, x) at which the SC gap amplitude is suppressed by field
have been determined; H^{2\Delta}_{c2}(T, x) is larger than H*_{c2}(T, x) for
all doping concentrations. The difference between the two quantities suggests
the presence of phase fluctuations that increase for x< 0.15. It is found that
the magnetic field suppresses the magnitude of the SC gap linearly at
surprisingly small fields.Comment: 13 pages, 8 figures; submitted to Phys. Rev.
- …