5,002 research outputs found
The impact of diet-based glycaemic response and glucose regulation on cognition: evidence across the lifespan
The brain has a high metabolic rate and its metabolism is almost entirely restricted to oxidative utilisation of glucose. These factors emphasise the extreme dependence of neural tissue on a stable and adequate supply of glucose. Whereas initially it was thought that only glucose deprivation (i.e. under hypoglycaemic conditions) can affect brain function, it has become apparent that low-level fluctuations in central availability can affect neural and consequently, cognitive performance. In the present paper the impact of diet-based glycaemic response and glucose regulation on cognitive processes across the lifespan will be reviewed. The data suggest that although an acute rise in blood glucose levels has some short-term improvements of cognitive function, a more stable blood glucose profile, which avoids greater peaks and troughs in circulating glucose is associated with better cognitive function and a lower risk of cognitive impairments in the longer term. Therefore, a habitual diet that secures optimal glucose delivery to the brain in the fed and fasting states should be most advantageous for the maintenance of cognitive function. Although the evidence to date is promising, it is insufficient to allow firm and evidence-based nutritional recommendations. The rise in obesity, diabetes and metabolic syndrome in recent years highlights the need for targeted dietary and lifestyle strategies to promote healthy lifestyle and brain function across the lifespan and for future generations. Consequently, there is an urgent need for hypothesis-driven, randomised controlled trials that evaluate the role of different glycaemic manipulations on cognition
Pengaruh Kompensasi dan Lingkungan Kerja pada Loyalitas Karyawan Berdasarkan Jenis Kelamin
This study aimed to examine the effect of compensation and work environment on employee loyalty by gender either simultaneously or partially.73 Respondnts as employees is determined using the method of saturated samples. Data were obtained through questionnaires,were analyzed using discriminant analysis techniques (discriminant analysis). Based on the analysis it was found that compensation and work environment simultaneously significant effect on employee loyalty. Partially compensated significant effect on employee loyalty. The working environment is partially no significant effect on employee loyalty
Quantum interference-induced stability of repulsively bound pairs of excitations
We study the dynamics of two types of pairs of excitations which are bound
despite their strong repulsive interaction. One corresponds to doubly occupied
sites in one-dimensional Bose-Hubbard systems, the so-called doublons. The
other is pairs of neighboring excited spins in anisotropic Heisenberg spin-1/2
chains. We investigate the possibility of decay of the bound pairs due to
resonant scattering by a defect or due to collisions of the pairs. We find that
the amplitudes of the corresponding transitions are very small. This is a
result of destructive quantum interference and explains the stability of the
bound pairs.Comment: 12 pages, 3 figure
Magneto-shear modes and a.c. dissipation in a two-dimensional Wigner crystal
The a.c. response of an unpinned and finite 2D Wigner crystal to electric
fields at an angular frequency has been calculated in the dissipative
limit, , where is the scattering rate. For
electrons screened by parallel electrodes, in zero magnetic field the
long-wavelength excitations are a diffusive longitudinal transmission line mode
and a diffusive shear mode. A magnetic field couples these modes together to
form two new magneto-shear modes. The dimensionless coupling parameter where and are the
speeds of transverse and longitudinal sound in the collisionless limit and
and are the tensor components of the
magnetoconductivity. For , both the coupled modes contribute
to the response of 2D electrons in a Corbino disk measurement of
magnetoconductivity. For , the electron crystal rotates rigidly in
a magnetic field. In general, both the amplitude and phase of the measured a.c.
currents are changed by the shear modulus. In principle, both the
magnetoconductivity and the shear modulus can be measured simultaneously.Comment: REVTeX, 7 pp., 4 eps figure
Bistability and Hysteresis of Intersubband Absorption in Strongly Interacting Electrons on Liquid Helium
We study nonlinear inter-subband microwave absorption of electrons bound to
the liquid helium surface. Already for a comparatively low radiation intensity,
resonant absorption due to transitions between the two lowest subbands is
accompanied by electron overheating. The overheating results in a significant
population of higher subbands. The Coulomb interaction between electrons causes
a shift of the resonant frequency, which depends on the population of the
excited states and thus on the electron temperature . The latter is
determined experimentally from the electron photoconductivity. The
experimentally established relationship between the frequency shift and
is in reasonable agreement with the theory. The dependence of the shift on the
radiation intensity introduces nonlinearity into the rate of the inter-subband
absorption resulting in bistability and hysteresis of the resonant response.
The hysteresis of the response explains the behavior in the regime of frequency
modulation, which we observe for electrons on liquid He and which was
previously seen for electrons on liquid He
Epidemiology of Any and Vaccine-Type Anogenital Human Papillomavirus Among 13-26-Year-Old Young Men After HPV Vaccine Introduction
PURPOSE:
The aims of this study were to determine prevalence of and factors associated with any human papillomavirus (HPV) and vaccine-type HPV among young men after vaccine introduction, stratified by vaccination status.
METHODS:
Young men were recruited from clinical sites from 2013 to 2015, completed a survey, and were tested for 36 anogenital HPV types. We determined factors associated with β₯1 HPV type among all participants, and vaccine-type HPV (HPV6, 11, 16, and/or 18) among all, vaccinated and unvaccinated participants, using multivariable regression.
RESULTS:
Mean age was 21.5 years and 26% had received at least one HPV vaccine dose. HPV prevalence was lower in vaccinated versus unvaccinated young men (50.5% vs. 62.6%, pβ=β.03). HPV positivity was discordant by anogenital site. At both sites, 59.4% were positive forββ₯1 HPV type and 26.0% forββ₯1 4-valent vaccine type. In multivariable logistic regression, factors associated withββ₯1 HPV type among all participants were frequency of oral sex (odds ratio [OR]β=β1.80, 95% confidence interval [CI]β=β1.00-3.24), recent smoking (ORβ=β1.84, CIβ=β1.17-2.90), and sexually transmitted infection history (ORβ=β1.56, CIβ=β1.02-2.38). Factors associated with vaccine-type HPV among all participants were white versus black race (ORβ=β1.91, CIβ=β1.10-3.34) and gonorrhea history (ORβ=β2.52, CIβ=β1.45-4.38); among vaccinated participants were private versus Medicaid insurance (ORβ=β5.6, CIβ=β1.46-20.4) and private versus no insurance (ORβ=β15.9, CIβ=β3.06-83.3); and among unvaccinated participants was gonorrhea history (ORβ=β1.83, CIβ=β1.03-3.24).
CONCLUSIONS:
Anogenital HPV prevalence was high and vaccination rates low among young men 2-4 years after vaccine introduction, underscoring the urgency of increasing vaccination rates and vaccinating according to national guidelines
Single electron magneto-conductivity of a nondegenerate 2D electron system in a quantizing magnetic field
We study transport properties of a non-degenerate two-dimensional system of
non-interacting electrons in the presence of a quantizing magnetic field and a
short-range disorder potential. We show that the low-frequency
magnetoconductivity displays a strongly asymmetric peak at a nonzero frequency.
The shape of the peak is restored from the calculated 14 spectral moments, the
asymptotic form of its high-frequency tail, and the scaling behavior of the
conductivity for omega -> 0. We also calculate 10 spectral moments of the
cyclotron resonance absorption peak and restore the corresponding
(non-singular) frequency dependence using the continuous fraction expansion.
Both expansions converge rapidly with increasing number of included moments,
and give numerically accurate results throughout the region of interest. We
discuss the possibility of experimental observation of the predicted effects
for electrons on helium.Comment: RevTeX 3.0, 14 pages, 8 eps figures included with eps
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