613 research outputs found
Coconut and sunflower oil ratios in ice cream influence subsequent food selection and intake
The effect of coconut oil (CO, containing mainly medium chain triglycerides - MCTs) and sunflower oil (SO, containing mainly long chain triglycerides - LCTs) used as fat source (10% fat ice cream) in different ratios (25% CO and 75% SO - 25CO:75SO, 50% CO and 50% SO - 50CO:50SO, 75% CO and 25% SO - 75CO:25SO) was investigated to assess differences in appetite and ad-libitum (evening and snack) food intake using a single blind design. 36 healthy female participants consumed a fixed portion (150 g) of ice cream 45 min before an ad-libitum dinner and snacks. Appetite sensations were tracked across the day. Participants ate significantly less fat after 75CO:25SO than 25CO:75SO (p = 0.007) and there was also a trend for lower fat intake in this condition as compared to 50CO:50SO (p = 0.068). High fat savoury snack intake significantly decreased after 75CO:25SO in comparison with both 25CO:75SO (p = 0.038) and 50CO:50SO (p = 0.008). Calorie intake from snacks was also found to be significantly lower after 25CO:75SO and 50CO:50SO than 75CO:25SO (p = 0.021 and 0.030 respectively). There was no effect of condition on appetite or desire ratings over the day. Eating a standard portion of ice cream containing different ratios of MCTs and LCTs can modestly influence acute food selection and intake, with MCTs manifesting their effect earlier and LCTs later due to differences in the absorption and metabolism of these lipids. However, the differences evident in the present study were small, and require further research before firm conclusions can be drawn
Enhancement of Loop Induced Vertex in Two Higgs-doublet Model
The non-decoupling effects of heavy Higgs bosons as well as fermions on the
loop-induced vertex are discussed in the general two Higgs
doublet model. The decay width of the process is calculated
at one-loop level and the possibility of its enhancement is explored both
analytically and numerically. We find that the novel enhancement of the decay
width can be realized by the Higgs non-decoupling effects with large
mass-splitting between the charged Higgs boson and the CP-odd one. This is due
to the large breakdown of the custodial invariance in the Higgs
sector. The branching ratio can amount to for GeV within the constraint from the present experimental data. Hence this
mode may be detectable at LHC or future linear colliders.Comment: 31+1 pages, Latex with 8 eps-file
Constraints on the pMSSM from LAT Observations of Dwarf Spheroidal Galaxies
We examine the ability for the Large Area Telescope (LAT) to constrain
Minimal Supersymmetric Standard Model (MSSM) dark matter through a combined
analysis of Milky Way dwarf spheroidal galaxies. We examine the Lightest
Supersymmetric Particles (LSPs) for a set of ~71k experimentally valid
supersymmetric models derived from the phenomenological-MSSM (pMSSM). We find
that none of these models can be excluded at 95% confidence by the current
analysis; nevertheless, many lie within the predicted reach of future LAT
analyses. With two years of data, we find that the LAT is currently most
sensitive to light LSPs (m_LSP < 50 GeV) annihilating into tau-pairs and
heavier LSPs annihilating into b-bbar. Additionally, we find that future LAT
analyses will be able to probe some LSPs that form a sub-dominant component of
dark matter. We directly compare the LAT results to direct detection
experiments and show the complementarity of these search methods.Comment: 24 pages, 9 figures, submitted to JCA
Chromomagnetic Dipole Moment of the Top Quark Revisited
We study the complete one-loop contributions to the chromagnetic dipole
moment of the top quark in the Standard Model, two Higgs doublet
models, topcolor assited technicolor models (TC2), 331 models and extended
models with a single extra dimension. We find that the SM predicts
and that the predictions of the other models are also
consitent with the constraints imposed on by low-energy
precision measurements.Comment: 20 pages, 5 figures, Updat
Combined analysis of Z' -> t tbar and Z' -> t tbar j production for vector resonance searches at LHC
We have implemented a code for Z' + n jets production in ALPGEN, with Z'
decays into several final states, including l+ l- and t tbar. The MLM
prescription is used for matching the matrix element with the parton shower,
including in this way the leading soft and collinear corrections. In order to
demonstrate its capabilities, we perform a combined analysis of Z' -> t tbar
and Z' -> t tbar j production for a heavy leptophobic gauge boson. It is found
that the effect of the extra jet cannot only be accounted for by a K factor
multiplying the leading-order cross section. In fact, the combined analysis for
Z' -> t tbar and Z' -> t tbar j presented improves the statistical significance
of the signal by 25% (8.55 sigma versus 6.77 sigma for a Z' mass of 1 TeV),
compared with the results of an inclusive analysis carried out on the same
sample of t tbar + t tbar j events.Comment: LaTeX 17 pages, 13 PS figure
Magnetization dynamics with a spin-transfer torque
The magnetization reversal and dynamics of a spin valve pillar, whose lateral
size is 6464 nm, are studied by using micromagnetic simulation in
the presence of spin transfer torque. Spin torques display both characteristics
of magnetic damping (or anti-damping) and of an effective magnetic field. For a
steady-state current, both M-I and M-H hysteresis loops show unique features,
including multiple jumps, unusual plateaus and precessional states. These
states originate from the competition between the energy dissipation due to
Gilbert damping and the energy accumulation due to the spin torque supplied by
the spin current. The magnetic energy oscillates as a function of time even for
a steady-state current. For a pulsed current, the minimum width and amplitude
of the spin torque for achieving current-driven magnetization reversal are
quantitatively determined. The spin torque also shows very interesting thermal
activation that is fundamentally different from an ordinary damping effect.Comment: 15 figure
The muon g-2 in a SU(7) left-right symmetric model with mirror fermions
We have studied a left-right symmetric model with mirror fermions based in a
grand unified SU(7) model in order to account for the muon anomaly. The Higgs
sector of the model contains two Higgs doublets and the hierarchy condition
can be achieved by using two additional Higgs
singlets, one even and other odd under
-parity. We show that there is a wide range of values for the
mass parameters of the model that is consistent with the lepton
anomalies.
Radiative correction to the mass of the ordinary fermions are shown to be
small
Constraining Supergravity Scenarios through the Decay.
We evaluate the branching ratio BR() in the minimal
supersymmetric standard model (MSSM), determining the corresponding
phenomenological restrictions on two attractive supergravity scenarios, namely
minimal supergravity and a class of models with a natural solution to the
problem. We have included in the calculation some one--loop refinements that
have a substantial impact on the results. The numerical results show some
disagreements with part of the previous results in the literature, while they
are in agreement with others. For minimal supergravity the CLEO upper and lower
bounds put important restrictions on the scalar and gaugino masses in both
cases . For the other supergravity scenarios the relevant
CLEO bound is the upper one. It is stressed the fact that an eventual
improvement of the experimental bounds of order would strengthen the
restrictions on the MSSM dramatically. This would be enough to discard these
supergravity scenarios with if no discrepancy is found with the
standard model prediction, while for there will remain low-energy
windows.Comment: 13 pages + 8 figures included in a separate file, Latex, requires
psfig.sty. We have corrected a mistake affecting some figures and their
corresponding quotations in the text, as well as several misprints
FCNC Top Quark Decays in Extra Dimensions
The flavor changing neutral top quark decay t -> c X is computed, where X is
a neutral standard model particle, in a extended model with a single extra
dimension. The cases for the photon, X= \gammaR_\xi gauge. We find that
the branching ratios can be enhanced by the dynamics originated in the extra
dimension. In the limit where 1/R >> ->, we have found Br(t -> c \gamma) \simeq
10^{-10} for 1/R = 0.5 TeV. For the decay t -> c H, we have found Br(t -> cH)
\simeq 10^{-10} for a low Higgs mass value. The branching ratios go to zero
when 1/R -> \infty.Comment: Accepted to be published in the Europ. Phys. Jour. C; 16 pages, 2
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