531 research outputs found
A solid state light-matter interface at the single photon level
Coherent and reversible mapping of quantum information between light and
matter is an important experimental challenge in quantum information science.
In particular, it is a decisive milestone for the implementation of quantum
networks and quantum repeaters. So far, quantum interfaces between light and
atoms have been demonstrated with atomic gases, and with single trapped atoms
in cavities. Here we demonstrate the coherent and reversible mapping of a light
field with less than one photon per pulse onto an ensemble of 10 millions atoms
naturally trapped in a solid. This is achieved by coherently absorbing the
light field in a suitably prepared solid state atomic medium. The state of the
light is mapped onto collective atomic excitations on an optical transition and
stored for a pre-programmed time up of to 1 mu s before being released in a
well defined spatio-temporal mode as a result of a collective interference. The
coherence of the process is verified by performing an interference experiment
with two stored weak pulses with a variable phase relation. Visibilities of
more than 95% are obtained, which demonstrates the high coherence of the
mapping process at the single photon level. In addition, we show experimentally
that our interface allows one to store and retrieve light fields in multiple
temporal modes. Our results represent the first observation of collective
enhancement at the single photon level in a solid and open the way to multimode
solid state quantum memories as a promising alternative to atomic gases.Comment: 5 pages, 5 figures, version submitted on June 27 200
Finite top quark mass effects in NNLO Higgs boson production at LHC
We present next-to-next-to-leading order corrections to the inclusive
production of the Higgs bosons at the CERN Large Hadron Collider (LHC)
including finite top quark mass effects. Expanding our analytic results for the
partonic cross section around the soft limit we find agreement with a very
recent publication by Harlander and Ozeren \cite{Harlander:2009mq}.Comment: 15 page
Production of scalar and pseudo-scalar Higgs bosons to next-to-next-to-leading order at hadron colliders
We consider the production of intermediate-mass CP-even and CP-odd Higgs
bosons in proton-proton and proton-anti-proton collisions. We extend the
recently published results for the complete next-to-next-to-leading order
calculation for a scalar Higgs boson to the pseudo-scalar case and present
details of the calculation that might be useful for similar future
investigations. The result is based on an expansion in the limit of a heavy top
quark mass and a subsequent matching to the expression obtained in the limit of
infinite energy. For a Higgs boson mass of 120 GeV the deviation from the
infinite-top quark mass result is small. For 300 GeV, however, the
next-to-next-to-leading order corrections for a scalar Higgs boson exceed the
effective-theory result by about 9% which increases to 22% in the pseudo-scalar
case. Thus in this mass range the effect on the total cross section amounts to
about 2% and 6%, respectively, which may be relevant in future precision
studies.Comment: 29 page
TOM40 Mediates Mitochondrial Dysfunction Induced by α-Synuclein Accumulation in Parkinson's Disease.
Alpha-synuclein (α-Syn) accumulation/aggregation and mitochondrial dysfunction play prominent roles in the pathology of Parkinson's disease. We have previously shown that postmortem human dopaminergic neurons from PD brains accumulate high levels of mitochondrial DNA (mtDNA) deletions. We now addressed the question, whether alterations in a component of the mitochondrial import machinery -TOM40- might contribute to the mitochondrial dysfunction and damage in PD. For this purpose, we studied levels of TOM40, mtDNA deletions, oxidative damage, energy production, and complexes of the respiratory chain in brain homogenates as well as in single neurons, using laser-capture-microdissection in transgenic mice overexpressing human wildtype α-Syn. Additionally, we used lentivirus-mediated stereotactic delivery of a component of this import machinery into mouse brain as a novel therapeutic strategy. We report here that TOM40 is significantly reduced in the brain of PD patients and in α-Syn transgenic mice. TOM40 deficits were associated with increased mtDNA deletions and oxidative DNA damage, and with decreased energy production and altered levels of complex I proteins in α-Syn transgenic mice. Lentiviral-mediated overexpression of Tom40 in α-Syn-transgenic mice brains ameliorated energy deficits as well as oxidative burden. Our results suggest that alterations in the mitochondrial protein transport machinery might contribute to mitochondrial impairment in α-Synucleinopathies
Tuberculosis in HIV-Negative and HIV-Infected Patients in a Low-Incidence Country: Clinical Characteristics and Treatment Outcomes
BACKGROUND: In Switzerland and other developed countries, the number of tuberculosis (TB) cases has been decreasing for decades, but HIV-infected patients and migrants remain risk groups. The aim of this study was to compare characteristics of TB in HIV-negative and HIV-infected patients diagnosed in Switzerland, and between coinfected patients enrolled and not enrolled in the national Swiss HIV Cohort Study (SHCS).
METHODS AND FINDINGS: All patients diagnosed with culture-confirmed TB in the SHCS and a random sample of culture-confirmed cases reported to the national TB registry 2000-2008 were included. Outcomes were assessed in HIV-infected patients and considered successful in case of cure or treatment completion. Ninety-three SHCS patients and 288 patients selected randomly from 4221 registered patients were analyzed. The registry sample included 10 (3.5%) coinfected patients not enrolled in the SHCS: the estimated number of HIV-infected patients not enrolled in the SHCS but reported to the registry 2000-2008 was 146 (95% CI 122-173). Coinfected patients were more likely to be from sub-Saharan Africa (51.5% versus 15.8%, P<0.0001) and to present disseminated disease (23.9% vs. 3.4%, P<0.0001) than HIV-negative patients. Coinfected patients not enrolled in the SHCS were asylum seekers or migrant workers, with lower CD4 cell counts at TB diagnosis (median CD4 count 79 cells/µL compared to 149 cells/µL among SHCS patients, P = 0.07). There were 6 patients (60.0%) with successful outcomes compared to 82 (88.2%) patients in the SHCS (P = 0.023).
CONCLUSIONS: The clinical presentation of coinfected patients differed from HIV-negative TB patients. The number of HIV-infected patients diagnosed with TB outside the SHCS is similar to the number diagnosed within the cohort but outcomes are poorer in patients not followed up in the national cohort. Special efforts are required to address the needs of this vulnerable population
RG-improved single-particle inclusive cross sections and forward-backward asymmetry in production at hadron colliders
We use techniques from soft-collinear effective theory (SCET) to derive
renormalization-group improved predictions for single-particle inclusive (1PI)
observables in top-quark pair production at hadron colliders. In particular, we
study the top-quark transverse-momentum and rapidity distributions, the
forward-backward asymmetry at the Tevatron, and the total cross section at
NLO+NNLL order in resummed perturbation theory and at approximate NNLO in fixed
order. We also perform a detailed analysis of power corrections to the leading
terms in the threshold expansion of the partonic hard-scattering kernels. We
conclude that, although the threshold expansion in 1PI kinematics is
susceptible to numerically significant power corrections, its predictions for
the total cross section are in good agreement with those obtained by
integrating the top-pair invariant-mass distribution in pair invariant-mass
kinematics, as long as a certain set of subleading terms appearing naturally
within the SCET formalism is included.Comment: 55 pages, 14 figures, 6 table
Radiotherapy alone for stage I-III low grade follicular lymphoma: long-term outcome and comparison of extended field and total nodal irradiation
Meta-analysis of genome-wide association studies from the CHARGE consortium identifies common variants associated with carotid intima media thickness and plaque
Carotid intima media thickness (cIMT) and plaque determined by ultrasonography are established measures of subclinical atherosclerosis that each predicts future cardiovascular disease events. We conducted a meta-analysis of genome-wide association data in 31,211 participants of European ancestry from nine large studies in the setting of the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) Consortium. We then sought additional evidence to support our findings among 11,273 individuals using data from seven additional studies. In the combined meta-analysis, we identified three genomic regions associated with common carotid intima media thickness and two different regions associated with the presence of carotid plaque (P < 5 × 10 -8). The associated SNPs mapped in or near genes related to cellular signaling, lipid metabolism and blood pressure homeostasis, and two of the regions were associated with coronary artery disease (P < 0.006) in the Coronary Artery Disease Genome-Wide Replication and Meta-Analysis (CARDIoGRAM) consortium. Our findings may provide new insight into pathways leading to subclinical atherosclerosis and subsequent cardiovascular events
State-of-the-art Review : Vol. 2B. Integrated Building Concepts:NNEX 44 : Integrating Environmentally Responsive Elements in Buildings
State-of-the-art Review : Vol. 2B. Methods and Tools for Designing Integrated Building Concepts:NNEX 44 : Integrating Environmentally Responsive Elements in Buildings
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