1,062 research outputs found
Bubble, Bubble, Flow and Hubble: Large Scale Galaxy Flow from Cosmological Bubble Collisions
We study large scale structure in the cosmology of Coleman-de Luccia bubble
collisions. Within a set of controlled approximations we calculate the effects
on galaxy motion seen from inside a bubble which has undergone such a
collision. We find that generically bubble collisions lead to a coherent bulk
flow of galaxies on some part of our sky, the details of which depend on the
initial conditions of the collision and redshift to the galaxy in question.
With other parameters held fixed the effects weaken as the amount of inflation
inside our bubble grows, but can produce measurable flows past the number of
efolds required to solve the flatness and horizon problems.Comment: 30 pages, 8 figures, pdftex, minor corrections and references adde
The PreAmplifier ShAper for the ALICE TPC-Detector
In this paper the PreAmplifier ShAper (PASA) for the Time Projection Chamber
(TPC) of the ALICE experiment at LHC is presented. The ALICE TPC PASA is an
ASIC that integrates 16 identical channels, each consisting of Charge Sensitive
Amplifiers (CSA) followed by a Pole-Zero network, self-adaptive bias network,
two second-order bridged-T filters, two non-inverting level shifters and a
start-up circuit. The circuit is optimized for a detector capacitance of 18-25
pF. For an input capacitance of 25 pF, the PASA features a conversion gain of
12.74 mV/fC, a peaking time of 160 ns, a FWHM of 190 ns, a power consumption of
11.65 mW/ch and an equivalent noise charge of 244e + 17e/pF. The circuit
recovers smoothly to the baseline in about 600 ns. An integral non-linearity of
0.19% with an output swing of about 2.1 V is also achieved. The total area of
the chip is 18 mm and is implemented in AMS's C35B3C1 0.35 micron CMOS
technology. Detailed characterization test were performed on about 48000 PASA
circuits before mounting them on the ALICE TPC front-end cards. After more than
two years of operation of the ALICE TPC with p-p and Pb-Pb collisions, the PASA
has demonstrated to fulfill all requirements
Can we detect Hot or Cold spots in the CMB with Minkowski Functionals?
In this paper, we investigate the utility of Minkowski Functionals as a probe
of cold/hot disk-like structures in the CMB. In order to construct an accurate
estimator, we resolve a long-standing issue with the use of Minkowski
Functionals as probes of the CMB sky -- namely that of systematic differences
("residuals") when numerical and analytical MF are compared. We show that such
residuals are in fact by-products of binning, and not caused by pixelation or
masking as originally thought. We then derive a map-independent estimator that
encodes the effects of binning, applicable to beyond our present work. Using
this residual-free estimator, we show that small disk-like effects (as claimed
by Vielva et al.) can be detected only when a large sample of such maps are
averaged over. In other words, our estimator is noise-dominated for small disk
sizes at WMAP resolution. To confirm our suspicion, we apply our estimator to
the WMAP7 data to obtain a null result.Comment: 15 pages, 13 figure
Energy Spectrum of Bloch Electrons Under Checkerboard Field Modulations
Two-dimensional Bloch electrons in a uniform magnetic field exhibit complex
energy spectrum. When static electric and magnetic modulations with a
checkerboard pattern are superimposed on the uniform magnetic field, more
structures and symmetries of the spectra are found, due to the additional
adjustable parameters from the modulations. We give a comprehensive report on
these new symmetries. We have also found an electric-modulation induced energy
gap, whose magnitude is independent of the strength of either the uniform or
the modulated magnetic field. This study is applicable to experimentally
accessible systems and is related to the investigations on frustrated
antiferromagnetism.Comment: 8 pages, 6 figures (reduced in sizes), submitted to Phys. Rev.
The Supersymmetric Standard Models with Decay and Stable Dark Matters
We propose two supersymmetric Standard Models (SMs) with decaying and stable
dark matter (DM) particles. To explain the SM fermion masses and mixings and
have a heavy decay DM particle S, we consider the Froggatt-Nielsen mechanism by
introducing an anomalous U(1)_X gauge symmetry. Around the string scale, the
U(1)_X gauge symmetry is broken down to a Z_2 symmetry under which S is odd
while all the SM particles are even. S obtains a vacuum expectation value
around the TeV scale, and then it can three-body decay dominantly to the
second/third family of the SM leptons in Model I and to the first family of the
SM leptons in Model II. Choosing a benchmark point in the constrained minimal
supersymmetric SM with exact R parity, we show that the lightest neutralino DM
is consistent with the CDMS II experiment. Considering S three-body decay and
choosing suitable parameters, we show that the PAMELA and Fermi-LAT experiments
and the PAMELA and ATIC experiments can be explained in Model I and Model II,
respectively.Comment: RevTex4, 26 pages, 6 figures, references added, version to appear in
EPJ
Medicare/medicaid insurance, rurality, and black race associated with provision of hepatocellular carcinoma treatment and survival
Background: Early treatment of hepatocellular carcinoma (HCC) is associated with improved survival, but many patients with HCC do not receive therapy. We aimed to examine factors associated with HCC treatment and survival among incident patients with HCC in a statewide cancer registry. Materials and Methods: All patients with HCC from 2003 through 2013 were identified in the North Carolina cancer registry. These patients were linked to insurance claims from Medicare, Medicaid, and large private insurers in North Carolina. Associations between prespecified covariates and more advanced HCC stage at diagnosis (ie, multifocal cancer), care at a liver transplant center, and provision of HCC treatment were examined using multivariate logistic regression. A Cox proportional hazards model was developed to assess the association between these factors and survival. Results: Of 1,809 patients with HCC, 53% were seen at a transplant center,90 days from diagnosis, with lower odds among those who were Black (adjusted odds ratio [aOR], 0.54; 95% CI, 0.39-0.74), had Medicare insurance (aOR, 0.35; 95% CI, 0.21-0.59), had Medicaid insurance (aOR, 0.46; 95% CI, 0.28-0.77), and lived in a rural area; odds of transplant center visits were higher among those who had prediagnosis alpha fetoprotein screening (aOR, 1.74; 95% CI, 1.35-2.23) and PCP and gastroenterology care (aOR, 1.66; 95% CI, 1.27-2.18). Treatment was more likely among patients who had prediagnosis gastroenterology care (aOR, 1.68; 95% CI, 0.98-2.86) and transplant center visits (aOR, 2.42; 95% CI, 1.74-3.36). Survival was strongly associated with age, cancer stage, cirrhosis complications, and receipt of HCC treatment. Individuals with Medicare (adjusted hazard ratio [aHR], 1.58; 95% CI, 1.20-2.09) and Medicaid insurance (aHR, 1.55; 95% CI, 1.17-2.05) had shorter survival than those with private insurance. Conclusions: In this population-based cohort of patients with HCC, Medicare/Medicaid insurance, rural residence, and Black race were associated with lower provision of HCC treatment and poorer survival. Efforts should be made to improve access to care for these vulnerable populations
Characterization of a Mixed Methanotrophic Culture Capable of Chloroethylene Degradation
A consortium of methanotrophs cultured from the St. Joseph's aquifer in Schoolcraft, MI, was found to exhibit similar methane consumption rates as pure cultures of methanotrophs. The methanotrophic consortium resides within a portion of the aquifer contaminated with a mixed waste plume of perchloroethylene (PCE) and its reductive dechlorination products from natural attenuation, trichloroethylene (TCE), cis-dichloroethylene (c-DCE), and vinyl chloride (VC). Oxidation kinetics for TCE, c-DCE, and VC were measured for the mixed methanotroph consortium and compared to reported rate parameters for degradation of these chloroethylene compounds by pure methanotrophic cultures. The results demonstrate that the kinetics of chloroethylene oxidation by the Schoolcraft methanotroph population mimic the degradation rates of pure methanotrophic cultures that primarily express particulate methane monooxygenase (pMMO). Molecular and biochemical analyses confirmed that sMMO was not being expressed by these cells. Rather, using competitive reverse transcriptionpolymerase chain reaction, pmoA, a gene encoding one of the polypeptides of the pMMO was found at a level of (1.57 ± 0.10) × 10–17 mol pmoA mRNA/g wet soil in soil slurries and (2.65 ± 0.43) × 10–17 mol pmoA mRNA/μl in groundwater. No expression of mmoX, a gene encoding one of the polypeptides of the sMMO, was detected.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63398/1/ees.2005.22.177.pd
Cloning of the gene and characterization of the enzymatic properties of the monomeric alkaline phosphatase (PhoX) from Pasteurella multocida strain X-73
We have identified a new phoX gene encoding the monomeric alkaline phosphatase from Pasteurella multocida X-73. This gene was not found in the published genome sequence of Pasteurella multocida pm70. Characterization of the recombinant PhoX of Pasteurella multocida X-73 showed that it is a monomeric enzyme, activated by Ca2+ and possibly secreted by the Tat pathway. These features distinguish phosphatases of the PhoX family from those of the PhoA family. All proteins of the PhoX family were found to contain a conserved motif that shares significant sequence homology with the calcium-binding site of a phosphotriesterase known as diisopropylfluorophosphatase. Site-directed mutagenesis revealed that D527 of PhoX might be the ligand bound to the catalytic calcium. This is the first report on identification of homologous sequences between PhoX and the phosphotriesterase and on the potential calcium-binding site of PhoX
De Sitter and Schwarzschild-De Sitter According to Schwarzschild and De Sitter
When de Sitter first introduced his celebrated spacetime, he claimed,
following Schwarzschild, that its spatial sections have the topology of the
real projective space RP^3 (that is, the topology of the group manifold SO(3))
rather than, as is almost universally assumed today, that of the sphere S^3.
(In modern language, Schwarzschild was disturbed by the non-local correlations
enforced by S^3 geometry.) Thus, what we today call "de Sitter space" would not
have been accepted as such by de Sitter. There is no real basis within
classical cosmology for preferring S^3 to RP^3, but the general feeling appears
to be that the distinction is in any case of little importance. We wish to
argue that, in the light of current concerns about the nature of de Sitter
space, this is a mistake. In particular, we argue that the difference between
"dS(S^3)" and "dS(RP^3)" may be very important in attacking the problem of
understanding horizon entropies. In the approach to de Sitter entropy via
Schwarzschild-de Sitter spacetime, we find that the apparently trivial
difference between RP^3 and S^3 actually leads to very different perspectives
on this major question of quantum cosmology.Comment: 26 pages, 8 figures, typos fixed, references added, equation numbers
finally fixed, JHEP versio
Geriatric assessment predicts hospitalization frequency and long-term care use in older adult cancer survivors
PURPOSE The association between geriatric assessment (GA)–identified impairments and long-term health care use in older cancer survivors remains unknown. Our objective was to evaluate whether a GA performed at cancer diagnosis was predictive of hospitalizations and long-term care (LTC) use in older adult cancer survivors. METHODS Older adults with GA performed between 3 months before through 6 months after diagnosis were included (N = 125). Patients with Medicare Parts A and B coverage and no managed care were identified. Hospitalizations and LTC use (skilled nursing or assisted living) were assessed up to 5 years postdiagnosis. GA risk measures were evaluated in separate Poisson models estimating the relative risk (RR) for hospital and LTC visits, adjusting for age and Charlson comorbidity score. RESULTS The mean age of patients was 74 years, and the majority were female (80%) and white (90%). Breast cancer (64%) and early-stage disease (stages 0 to III, 77%) were common. Prefrail/frail status (RR, 2.5; P, .001), instrumental activities of daily living impairment (RR, 5.47; P, .001), and limitations in climbing stairs (RR, 2.94; P, .001) were associated with increased hospitalizations. Prefrail/frail status (RR, 1.86; P, .007), instrumental activities of daily living impairment (RR, 4.58; P, .001), presence of falls (RR, 6.73; P, .001), prolonged Timed Up and Go (RR, 5.45; P, .001), and limitations in climbing stairs (RR, 1.89; P, .005) were associated with LTC use. CONCLUSION GA-identified impairments were associated with increased hospitalizations and LTC use among older adults with cancer. GA-focused interventions should be targeted toward high-risk patients to reduce long-term adverse health care use in this vulnerable population
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