223 research outputs found
Changes in muscular activity while imagining weight lifting using stimulus or response propositions
Investigating emotional imagery, Lang (1977, 1979) proposed a dichotomy between stimulus and response propositions. In this study, Lang’s model is applied to movement images of lifting of 4.5 and 9 kg weights. Twenty-two male and 17 female students participated in the study. During the imaginary lifting of the weights, the electromyographical activity (EMG) of both biceps brachii muscles were assessed. Imagery ability was measured with the Movement Imagery Questionnaire (MIQ) and another self-report rating scale. When response propositions were emphasized in the script, imaginary weight lifting resulted in greater muscle activity than when stimulus propositions were emphasized. During imagined lifting, EMG activity of the active arm was greater than that of the passive arm. In addition, in the active arm, a significant difference in EMG activity was found between 9 kg and 4.5 kg. It was concluded that Lang’s model is also applicable to emotionally neutral movement imagery.</jats:p
GPS/INS Integration Accuracy Enhancement Using the Interacting Multiple Model Nonlinear Filters
In this paper, performance evaluation for various single model nonlinear filters and nonlinear filters with interactingmultiple model (IMM) framework is carried out. A high gain (high bandwidth) filter is needed to response fast enoughto the platform maneuvers while a low gain filter is necessary to reduce the estimation errors during the uniformmotion periods. Based on a soft-switching framework, the IMM algorithm allows the possibility of using highly dynamicmodels just when required, diminishing unrealistic noise considerations in non-maneuvering situations. The IMMestimator obtains its estimate as a weighted sum of the individual estimates from a number of parallel filters matchedto different motion modes of the platform. The use of an IMM allows exploiting the benefits of high dynamic models inthe problem of vehicle navigation. Simulation and experimental results presented in this paper confirm theeffectiveness of the method
Relationship of fetal alanine uptake and placental alanine metabolism to maternal plasma alanine concentration
Uterine and umbilical uptakes of alanine (Ala) were measured in 10 ewes
before (control) and during intravenous infusion of Ala, which increased
maternal arterial Ala concentration from 115 +/- 14 to 629 +/- 78 microM
(P < 0.001). In 8 of these ewes, placental Ala fluxes were traced by
constant intravenous infusion of L-[3,3,3-2H3]Ala in the mother and
L-[1-13C]Ala in the fetus. Rates are reported as micromoles per minute per
kilogram fetus. Ala infusion increased uterine uptake (2.5 +/- 0.6 to 15.6
+/- 3.1, P < 0.001), umbilical uptake (3.1 +/- 0.5 to 6.9 +/- 0.8, P <
0.001), and net uteroplacental utilization (-0.7 +/- 0.8 to 8.6 +/- 2.7, P
< 0.01) of Ala. Control Ala flux to fetus from mother (Rf,m) was much less
than the Ala flux to fetus from placenta (Rf,p) (0.17 +/- 0.04 vs. 5. 0
+/- 0.6). Two additional studies utilizing L-[U-13C]Ala as the maternal
tracer confirmed the small relative contribution of Rf,m to Rf,p. During
maternal Ala infusion, Rf,m increased significantly (P < 0.02) but
remained a small fraction of Rf,p (0.71 +/- 0.2 vs. 7.3 +/- 1.3). We
conclude that maternal Ala entering the placenta is metabolized and
exchanged for placental Ala, so that most of the Ala delivered to the
fetus is produced within the placenta. An increase in maternal Ala
concentration increases placental Ala utilization and the fetal uptake of
both maternal and placental Ala
The antiferromagnetic phi4 Model, II. The one-loop renormalization
It is shown that the four dimensional antiferromagnetic lattice phi4 model
has the usual non-asymptotically free scaling law in the UV regime around the
chiral symmetrical critical point. The theory describes a scalar and a
pseudoscalar particle. A continuum effective theory is derived for low
energies. A possibility of constructing a model with a single chiral boson is
mentioned.Comment: To appear in Phys. Rev.
A simple variational approach to the quantum Frenkel-Kontorova model
We present a simple and complete variational approach to the one-dimensional
quantum Frenkel-Kontorova model. Dirac's time-dependent variational principle
is adopted together with a Hatree-type many-body trial wavefunction for the
atoms. The single-particle state is assumed to have the Jackiw-Kerman form. We
obtain an effective classical Hamiltonian for the system which is simple enough
for a complete numerical solution for the static ground state of the model.
Numerical results show that our simple approach captures the essence of the
quantum effects first observed in quantum Monte Carlo studies.Comment: 12 pages, 2 figure
In situ observations of coral spawning and spawn slick at Lankayan Island, Sabah, Malaysia
Sexual reproduction of corals is one of the most important processes for the persistence of coral populations. The Coral Triangle is recognised as a global hotspot of marine biodiversity, harbouring 75% of the world coral species. However, coral reproductive studies remain underrepresented in many reefs in the Coral Triangle. This study reports the coral spawning and spawn slicks occurrences from 2012 to 2019 at Lankayan Island, Malaysia, a small island located in the Sulu Sea at the westernmost boundary of the Coral Triangle. A total of 14 species belonging to three genera and two families were recorded to spawn on the reefs between March and May in 2012–2015 and 2019. Between one and eight species spawned on each observed spawning night. Acropora corals appear to dominate the spawning events based on direct observations on the reefs. Coral-spawn slicks were observed during March to May every year and in October 2019. We observed coral spawning between March and May in Lankayan Island, similar to other localities within the Coral Triangle. © 2021, Senckenberg Gesellschaft für Naturforschung
What Can WMAP Tell Us About The Very Early Universe? New Physics as an Explanation of Suppressed Large Scale Power and Running Spectral Index
The Wilkinson Microwave Anisotropy Probe microwave background data may be
giving us clues about new physics at the transition from a ``stringy'' epoch of
the universe to the standard Friedmann Robertson Walker description. Deviations
on large angular scales of the data, as compared to theoretical expectations,
as well as running of the spectral index of density perturbations, can be
explained by new physics whose scale is set by the height of an inflationary
potential. As examples of possible signatures for this new physics, we study
the cosmic microwave background spectrum for two string inspired models: 1)
modifications to the Friedmann equations and 2) velocity dependent potentials.
The suppression of low ``l'' modes in the microwave background data arises due
to the new physics. In addition, the spectral index is red (n<1) on small
scales and blue (n>1) on large scales, in agreement with data.Comment: 18 pages, 2 figures, submitted for publication in Physical Review D,
references added in this versio
Isospin-mixing corrections for fp-shell Fermi transitions
Isospin-mixing corrections for superallowed Fermi transitions in {\it
fp}-shell nuclei are computed within the framework of the shell model. The
study includes three nuclei that are part of the set of nine accurately
measured transitions as well as five cases that are expected to be measured in
the future at radioactive-beam facilities. We also include some new
calculations for C. With the isospin-mixing corrections applied to the
nine accurately measured values, the conserved-vector-current hypothesis
and the unitarity condition of the Cabbibo-Kobayashi-Maskawa (CKM) matrix are
tested.Comment: 13 pages plus five tables. revtex macro
Standard Model baryogenesis through four-fermion operators in braneworlds
We study a new baryogenesis scenario in a class of braneworld models with low
fundamental scale, which typically have difficulty with baryogenesis. The
scenario is characterized by its minimal nature: the field content is that of
the Standard Model and all interactions consistent with the gauge symmetry are
admitted. Baryon number is violated via a dimension-6 proton decay operator,
suppressed today by the mechanism of quark-lepton separation in extra
dimensions; we assume that this operator was unsuppressed in the early Universe
due to a time-dependent quark-lepton separation. The source of CP violation is
the CKM matrix, in combination with the dimension-6 operators. We find that
almost independently of cosmology, sufficient baryogenesis is nearly impossible
in such a scenario if the fundamental scale is above 100 TeV, as required by an
unsuppressed neutron-antineutron oscillation operator. The only exception
producing sufficient baryon asymmetry is a scenario involving
out-of-equilibrium c quarks interacting with equilibrium b quarks.Comment: 39 pages, 5 figures v2: typos, presentational changes, references and
acknowledgments adde
Phevamine A, a small molecule that suppresses plant immune responses
Bacterial plant pathogens cause significant crop damage worldwide. They invade plant cells by producing a variety of virulence factors, including small-molecule toxins and phytohormone mimics. Virulence of the model pathogen Pseudomonas syringae pv. tomato DC3000 (Pto) is regulated in part by the sigma factor HrpL. Our study of the HrpL regulon identified an uncharacterized, three-gene operon in Pto that is controlled by HrpL and related to the Erwinia hrp-associated systemic virulence (hsv) operon. Here, we demonstrate that the hsv operon contributes to the virulence of Pto on Arabidopsis thaliana and suppresses bacteria-induced immune responses. We show that the hsv-encoded enzymes in Pto synthesize a small molecule, phevamine A. This molecule consists of L-phenylalanine, L-valine, and a modified spermidine, and is different from known small molecules produced by phytopathogens. We show that phevamine A suppresses a potentiation effect of spermidine and L-arginine on the reactive oxygen species burst generated upon recognition of bacterial flagellin. The hsv operon is found in the genomes of divergent bacterial genera, including ∼37% of P. syringae genomes, suggesting that phevamine A is a widely distributed virulence factor in phytopathogens. Our work identifies a small-molecule virulence factor and reveals a mechanism by which bacterial pathogens overcome plant defense. This work highlights the power of omics approaches in identifying important small molecules in bacteria-host interactions
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