68 research outputs found

    Comment on "Quantitative Condition is Necessary in Guaranteeing the Validity of the Adiabatic Approximation" [arXiv:1004.3100]

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    Recently, the authors of Ref.1[arXiv:1004.3100] claimed that they have proven the traditional adiabatic condition is a necessary condition. Here, it is claimed that there are some mistakes and an artificial over-strong constraint in [1], making its result inconvincible.Comment: 1 pag

    Unparticle inspired corrections to the Gravitational Quantum Well

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    We consider unparticle inspired corrections of the type (RGr)β{(\frac{R_{G}}{r})}^\beta to the Newtonian potential in the context of the gravitational quantum well. The new energy spectrum is computed and bounds on the parameters of these corrections are obtained from the knowledge of the energy eigenvalues of the gravitational quantum well as measured by the GRANIT experiment.Comment: Revtex4 file, 4 pages, 2 figures and 1 table. Version to match the one published at Physical Review

    The rad18 Gene of Schizosaccharomyces pombe Defines a New Subgroup of the SMC Superfamily Involved in DNA Repair

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    The rad18 mutant of Schizosaccharomyces pombe is very sensitive to killing by both UV and ¿ radiation. We have cloned and sequenced the rad18 gene and isolated and sequenced its homolog from Saccharomyces cerevisiae, designated RHC18. The predicted Rad18 protein has all the structural properties characteristic of the SMC family of proteins, suggesting a motor function- the first implicated in DNA repair. Gene deletion shows that both rad18 and RHC18 are essential for proliferation. Genetic and biochemical analyses suggest that the product of the rad18 gene acts in a DNA repair pathway for removal of UV-induced DNA damage that is distinct from classical nucleotide excision repair. This second repair pathway involves the products of the rhp51 gene (the homolog of the RAD51 gene of S. cerevisiae) and the rad2 gene

    Dismounted Soldier Positioning in GNSS-Denied Environments Using Magnetic Fields

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    Situational awareness provided by robust and resilient positioning systems is mission-critical for many military applications and emergency services. Global Navigation Satellite Systems (GNSS) receivers are ubiquitous. However, GNSS signals can be denied, degraded or otherwise unavailable in many operational environments, necessitating one or more additional positioning navigation and timing (PNT) technologies to be available to the user. No single PNT technology, including GNSS, is sufficient in all operational environments. Therefore, a multisensor integrated system using a system of subsystems is required. This PhD project focuses on dismounted soldier positioning based on subsystems derived from inertial and magnetic measurement units (IMMU). Inertial navigation is well-researched for pedestrians; however, map matching derived positioning using magnetometers is under-researched, particularly the effect of different environments on performance. This magnetic-derived subsystem does not require new sensors but complements the commonly used IMMU system

    Top-down social modulation of interpersonal observation-execution.

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    Cyclical upper limb movement can involuntarily deviate from its primary movement axis when the performer concurrently observes incongruent biological motion (i.e. interpersonal observation-execution). The current study examined the social modulation of such involuntary motor interference using a protocol that reflected everyday social interactions encountered in a naturalistic social setting. Eighteen participants executed cyclical horizontal arm movements during the observation of horizontal (congruent) or curvilinear (incongruent) biological motion. Both prior to, and during the interpersonal observation-execution task, participants also received a series of social words designed to prime a pro-social or anti-social attitude. The results showed greater orthogonal movement deviation, and thus interference, for the curvilinear compared to horizontal stimuli. Importantly, and opposite to most of the previous findings from work on automatic imitation and mimicry, there was a greater interference effect for the anti-social compared to pro-social prime condition. These findings demonstrate the importance of interpreting the context of social primes, and strongly support predictions of a comparison between the prime construct and the self-concept/-schema and the top-down response modulation of social incentives

    Genome-wide comparative analysis of microRNAs in three non-human primates

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    Abstract Background MicroRNAs (miRNAs) are negative regulators of gene expression in multicellular eukaryotes. With the recently completed sequencing of three primate genomes, the study of miRNA evolution within the primate lineage has only begun and may be expected to provide the genetic and molecular explanations for many phenotypic differences between human and non-human primates. Findings We scanned all three genomes of non-human primates, including chimpanzee (Pan troglodytes), orangutan (Pongo pygmaeus), and rhesus monkey (Macaca mulatta), for homologs of human miRNA genes. Besides sequence homology analysis, our comparative method relies on various postprocessing filters to verify other features of miRNAs, including, in particular, their precursor structure or their occurrence (prediction) in other primate genomes. Our study allows direct comparisons between the different species in terms of their miRNA repertoire, their evolutionary distance to human, the effects of filters, as well as the identification of common and species-specific miRNAs in the primate lineage. More than 500 novel putative miRNA genes have been discovered in orangutan that show at least 85 percent identity in precursor sequence. Only about 40 percent are found to be 100 percent identical with their human ortholog. Conclusion Homologs of human precursor miRNAs with perfect or near-perfect sequence identity may be considered to be likely functional in other primates. The computational identification of homologs with less similar sequence, instead, requires further evidence to be provided.</p

    Evidence of Novel Quasiparticles in a Strongly Interacting Two-Dimensional Electron System: Giant Thermopower and Metallic Behaviour

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    We report thermopower (SS) and electrical resistivity (ρ2DES\rho_{2DES}) measurements in low-density (1014^{14} m2^{-2}), mesoscopic two-dimensional electron systems (2DESs) in GaAs/AlGaAs heterostructures at sub-Kelvin temperatures. We observe at temperatures \lesssim 0.7 K a linearly growing SS as a function of temperature indicating metal-like behaviour. Interestingly this metallicity is not Drude-like, showing several unusual characteristics: i) the magnitude of SS exceeds the Mott prediction valid for non-interacting metallic 2DESs at similar carrier densities by over two orders of magnitude; and ii) ρ2DES\rho_{2DES} in this regime is two orders of magnitude greater than the quantum of resistance h/e2h/e^2 and shows very little temperature-dependence. We provide evidence suggesting that these observations arise due to the formation of novel quasiparticles in the 2DES that are not electron-like. Finally, ρ2DES\rho_{2DES} and SS show an intriguing decoupling in their density-dependence, the latter showing striking oscillations and even sign changes that are completely absent in the resistivity.Comment: QFS2012 Conference proceedings, Journal of Low Temperature Physics, accepted (figure and discussion added upon referee suggestions

    Raltegravir-intensified initial antiretroviral therapy in advanced HIV in Africa: a randomized controlled trial

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    BACKGROUND: In sub-Saharan Africa, severely immunocompromised HIV-infected individuals have high mortality (10%) shortly after starting antiretroviral therapy (ART). This group also have the greatest risk of morbidity and mortality associated with immune reconstitution inflammatory syndrome (IRIS), a paradoxical response to successful ART. Integrase inhibitors lead to significantly more rapid declines in HIV viral load (VL) than all other ART classes. We hypothesised that intensifying standard triple-drug ART with the integrase inhibitor, raltegravir, would reduce HIV VL faster, and hence reduce early mortality, although this strategy could also risk more IRIS events. METHODS AND FINDINGS: In a 2x2x2 factorial open-label parallel-group trial, treatment-naïve HIV-infected adults, adolescents and children >5 years with CD4 0.7), and despite significantly greater VL suppression with raltegravir-intensified-ART at 4-weeks (343/836 (41.0%) vs 113/841 (13.4%) standard-ART, p<0.001) and 12-weeks (567/789 (71.9%) vs 415/803 (51.7%) standard-ART, p<0.001). Through 48-weeks there was no evidence of differences in mortality (aHR=0.98 (95%CI 0.76-1.28) p=0.91); serious (aHR=0.99 (0.81-1.21) p=0.88), grade-4 (aHR=0.88 (0.71-1.09) p=0.29) or ART-modifying (aHR=0.90 (0.63-1.27) p=0.54) adverse events (the latter occurring in occurring in 59 (6.5%) raltegravir-intensified-ART vs 66 (7.3%) standard-ART); in events judged compatible with IRIS (occurring in 89 (9.9%) raltegravir-intensified-ART vs 86 (9.5%) standard-ART, p=0.79) or hospitalizations (aHR=0.94 (95%CI 0.76-1.17) p=0.59). At 12 weeks, one and two raltegravir-intensified participants had predicted intermediate-level and high-level raltegravir resistance respectively. At 48 weeks, the NRTI mutation K219E/Q (p=0.004), and the NNRTI mutations K101E/P (p=0.03) and P225H (p=0.007), were less common in raltegravir-intensified-ART, with weak evidence of less intermediate or high-level resistance to tenofovir (p=0.06), abacavir (p=0.08) and rilpivirine (p=0.07). Limitations were limited clinical, radiological and/or microbiological information for some participants, reflecting available services at the centres, and lack of baseline genotypes. CONCLUSIONS: Although 12-weeks raltegravir-intensification was well-tolerated and reduced HIV viraemia significantly faster than standard triple-drug ART during the time of greatest risk for early death, this strategy did not reduce mortality or clinical events, and is not warranted. There was no excess of IRIS-compatible events, suggesting integrase inhibitors can be used safely as part of standard triple-drug first-line therapy in severely immuno-compromised individuals
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