6,541 research outputs found
Properties of Light Flavour Baryons in Hypercentral quark model
The light flavour baryons are studied within the quark model using the hyper
central description of the three-body system. The confinement potential is
assumed as hypercentral coulomb plus power potential () with power
index . The masses and magnetic moments of light flavour baryons are
computed for different power index, starting from 0.5 to 1.5. The
predicted masses and magnetic moments are found to attain a saturated value
with respect to variation in beyond the power index 1.0. Further
we computed transition magnetic moments and radiative decay width of light
flavour baryons. The results are in good agreement with known experimental as
well as other theoretical models.Comment: Accepted in Pramana J. of Physic
Effect of a qigong intervention program on telomerase activity and psychological stress in abused Chinese women: a randomized, wait-list controlled trial
BACKGROUND: Abused women, who suffer from chronic psychological stress, have been shown to have shorter telomeres than never abused women. Telomere shortening is associated with increased risk of cell death, and it is believed that adopting health-promoting behaviors can help to increase the activity of telomerase, an enzyme that counters telomere shortening. Qigong is an ancient Chinese mind-body integration, health-oriented practice designed to enhance the function of qi, an energy that sustains well-being. Therefore, an assessor-blind, randomized, wait-list controlled trial was developed to evaluate the effect of a qigong intervention on telomerase activity (primary objective) and proinflammatory cytokines, perceived stress, perceived coping, and depressive symptoms (secondary objectives) in abused Chinese women. METHODS/DESIGN: A total of 240 Chinese women, aged >/= 18 years, who have been abused by an intimate partner within the past three years will be recruited from a community setting in Hong Kong and randomized to receive either a qigong intervention or wait-list control condition as follows: the qigong intervention will comprise (i) a 2-hour group qigong training session twice a week for 6 weeks, (ii) a 1-hour follow-up group qigong exercise session once a week for 4 months, and (iii) a 30-minute self-practice qigong exercise session once a day for 5.5 months. The wait-list control group will receive qigong training after the intervention group completes the program. Upon completion of the qigong intervention program, it is expected that abused Chinese women in the intervention group will have higher levels of telomerase activity and perceived coping and lower levels of proinflammatory cytokines, perceived stress, and depressive symptoms than will abused Chinese women in the wait-list control group. DISCUSSION: This study will provide information about the effect of qigong exercise on telomerase activity and chronic psychological stress in abused Chinese women. The findings will inform the design of interventions to relieve the effects of IPV-related psychological stress on health. Also, the concept that health-promoting behaviors could slow down cellular aging might even motivate abused women to change their lifestyles. TRIAL REGISTRATION: Current Controlled Trials NCT02060123. Registered February 6, 2014.published_or_final_versio
Human B-cell Ontogeny in Humanized NOD/SCID γc Mice Generates a Diverse Yet Auto/Poly- and HIV-1 Reactive Antibody Repertoire
Characterization of the human antibody (Ab) repertoire in mouse models of the human immune system is essential to establish their relevance in translational studies. Single human B-cells were sorted from bone marrow and periphery of humanized NOD/SCID γc mice at 8–10 months post-engraftment with human cord blood-derived CD34 stem cells. Human immunoglobulin variable heavy (V) and kappa (V) genes were amplified, cognate V-V gene-pairs assembled as single-chain variable fragment-Fc antibodies (scFvFcs) and functional studies performed. Although overall distribution of V genes approximated the normal human Ab repertoire, analysis of the V-third complementarity determining regions (H-CDR3) in the mature B-cell subset demonstrated an increase in length and positive charges suggesting autoimmune characteristics. Additionally, >70% of Vκ sequences utilized V4-1, a germline gene associated with autoimmunity. The mature B-cell subset-derived scFvFcs displayed the highest frequency of autoreactivity and polyspecificity, suggesting defects in checkpoint control mechanisms. Furthermore, these scFvFcs demonstrated binding to recombinant HIV envelope corroborating previous observations of poly/autoreactivity in anti-HIVgp140 antibodies. These data lend support to the hypothesis that anti-HIV BnAbs may be derived from auto/polyspecific Abs that escaped immune elimination and that the hNSG mouse could provide a new experimental platform for studying the origin of anti-HIV neutralizing Ab responses
Conductivity and quasinormal modes in holographic theories
We show that in field theories with a holographic dual the retarded Green's
function of a conserved current can be represented as a convergent sum over the
quasinormal modes. We find that the zero-frequency conductivity is related to
the sum over quasinormal modes and their high-frequency asymptotics via a sum
rule. We derive the asymptotics of the quasinormal mode frequencies and their
residues using the phase-integral (WKB) approach and provide analytic insight
into the existing numerical observations concerning the asymptotic behavior of
the spectral densities.Comment: 24 pages, 3 figure
On-demand semiconductor single-photon source with near-unity indistinguishability
Single photon sources based on semiconductor quantum dots offer distinct
advantages for quantum information, including a scalable solid-state platform,
ultrabrightness, and interconnectivity with matter qubits. A key prerequisite
for their use in optical quantum computing and solid-state networks is a high
level of efficiency and indistinguishability. Pulsed resonance fluorescence
(RF) has been anticipated as the optimum condition for the deterministic
generation of high-quality photons with vanishing effects of dephasing. Here,
we generate pulsed RF single photons on demand from a single,
microcavity-embedded quantum dot under s-shell excitation with 3-ps laser
pulses. The pi-pulse excited RF photons have less than 0.3% background
contributions and a vanishing two-photon emission probability.
Non-postselective Hong-Ou-Mandel interference between two successively emitted
photons is observed with a visibility of 0.97(2), comparable to trapped atoms
and ions. Two single photons are further used to implement a high-fidelity
quantum controlled-NOT gate.Comment: 11 pages, 11 figure
Network adaptation improves temporal representation of naturalistic stimuli in drosophila eye: II Mechanisms
Retinal networks must adapt constantly to best present the ever changing visual world to the brain. Here we test the hypothesis that adaptation is a result of different mechanisms at several synaptic connections within the network. In a companion paper (Part I), we showed that adaptation in the photoreceptors (R1-R6) and large monopolar cells (LMC) of the Drosophila eye improves sensitivity to under-represented signals in seconds by enhancing both the amplitude and frequency distribution of LMCs' voltage responses to repeated naturalistic contrast series. In this paper, we show that such adaptation needs both the light-mediated conductance and feedback-mediated synaptic conductance. A faulty feedforward pathway in histamine receptor mutant flies speeds up the LMC output, mimicking extreme light adaptation. A faulty feedback pathway from L2 LMCs to photoreceptors slows down the LMC output, mimicking dark adaptation. These results underline the importance of network adaptation for efficient coding, and as a mechanism for selectively regulating the size and speed of signals in neurons. We suggest that concert action of many different mechanisms and neural connections are responsible for adaptation to visual stimuli. Further, our results demonstrate the need for detailed circuit reconstructions like that of the Drosophila lamina, to understand how networks process information
Assessing current genetic status of the Hainan gibbon using historical and demographic baselines: implications for conservation management of species of extreme rarity
Evidence-based conservation planning is crucial for informing management decisions for species of extreme rarity, but collection of robust data on genetic status or other parameters can be extremely challenging for such species. The Hainan gibbon, possibly the world's rarest mammal, consists of a single population of c.25 individuals restricted to one protected area on Hainan Island, China, and has persisted for over 30 years at exceptionally low population size. Analysis of genotypes at 11 microsatellite loci from faecal samples for 36% of the current global population and tissue samples from 62% of existing historical museum specimens demonstrates limited current genetic diversity (Na=2.27, Ar=2.24, He =0.43); diversity has declined since the 19th century and even further within the last 30 years, representing declines of c.30% from historical levels (Na=3.36, Ar=3.29, He =0.63). Significant differentiation is seen between current and historical samples (FST =0.156, P=0.0315), and the current population exhibits extremely small Ne (current Ne =2.16). There is evidence for both a recent population bottleneck and an earlier bottleneck, with population size already reasonably low by the late 19th century (historical Ne =1162.96). Individuals in the current population are related at the level of half- to full-siblings between social groups, and full-siblings or parent-offspring within a social group, suggesting that inbreeding is likely to increase in the future. The species' current reduced genetic diversity must be considered during conservation planning, particularly for expectations of likely population recovery, indicating that intensive, carefully planned management is essential
Determinants Of Economic Growth: Evidence From American Countries
This paper explores determinants of economic growth using variables from traditional Solow model and recent empirical studies. The study covers data on American countries during the period 1995-2006. The estimates show that per capita, GDP growth is positively related to capital expenditure, primary completion rate and trade openness and the relationship is statistically significant. Furthermore, population growth rate and investment in research and development have positive impacts on economic growth, yet the effects are not significant
The impact of remote ischemic preconditioning on cardiac biomarker and functional response to endurance exercise.
Remote ischemic preconditioning (RIPC; repeated short reversible periods of ischemia) protects the heart against subsequent ischemic injury. We explored whether RIPC can attenuate post-exercise changes in cardiac troponin T (cTnT) and cardiac function in healthy individuals. In a randomized, crossover design, 14 participants completed 1-h cycling time trials (TT) on two separate visits; preceded by RIPC (arms/legs, 4 × 5-min 220 mmHg), or SHAM-RIPC (20 mmHg). Venous blood was sampled before and 0-, 1-, and 3-h post-exercise to assess high sensitivity (hs-)cTnT and brain natriuretic peptide (NT-proBNP). Echocardiograms were performed at the same time points to assess left and right ventricular systolic (ejection fraction; EF and right ventricular fractional area change; RVFAC, respectively) and diastolic (early transmitral flow velocities; E) function. Baseline hs-cTnT was not different between RIPC and SHAM. Post-exercise hs-cTnT levels were consistently lower following RIPC (18 ± 3 vs 21 ± 3; 19 ± 3 vs 23 ± 3; and 20 ± 2 vs 25 ± 2 ng/L at 0, 1 and 3-h post-exercise, respectively; P < 0.05). There was no main effect of time, trial, or interaction for NT-proBNP and left ventricular EF or RVFAC (all P < 0.05). A main effect of time was evident for E which transiently declined immediately after exercise to a similar level in both trials (0.85 ± 0.04 vs 0.74 ± 0.04 m/s, respectively; P < 0.05). In summary, RIPC was associated with lower hs-cTnT levels after exercise but there was no independent effect of RIPC for NT-proBNP or LV systolic and diastolic function. The lower hs-cTnT levels after RIPC suggests that further research should evaluate the role of ischemia in exercise-induced elevation in hs-cTnT
- …
