9,801 research outputs found
Imaging of an early memory trace in the Drosophila mushroom body
Extensive molecular, genetic, and anatomical analyses have suggested that olfactory memory is stored in the mushroom body (MB), a higher-order olfactory center in the insect brain. The MB comprises three subtypes of neurons with axons that extend into different lobes. A recent functional imaging study has revealed a long-term memory trace manifested as an increase in the Ca(2+) activity in an axonal branch of a subtype of MB neurons. However, early memory traces in the MB remain elusive. We report here learning-induced changes in Ca(2+) activities during early memory formation in a different subtype of MB neurons. We used three independent in vivo and in vitro preparations, and all of them showed that Ca(2+) activities in the axonal branches of alpha'/beta' neurons in response to a conditioned olfactory stimulus became larger compared with one that was not conditioned. The changes were dependent on proper G-protein signaling in the MB. The importance of these changes in the Ca(2+) activity of alpha'/beta' neurons during early memory formation was further tested behaviorally by disrupting G-protein signaling in these neurons or blocking their synaptic outputs during the learning and memory process. Our results suggest that increased Ca(2+) activity in response to a conditioned olfactory stimulus may be a neural correlate of early memory in the MB
Determination of Dynamic Shear Modulus of Soils from Static Strength
A correlation study between the dynamic shear modulus obtained from the resonant column technique and the static strength obtained from the undrained triaxial compression test is described. The materials studied were a uniform sand, a non-active fine silty clay and a highly-active bentonite clay treated with additives to increase the range for static and dynamic shear strength of the soils. It is noted that a linear relationship exists between the dynamic shear modulus, except for those soil specimens having very low strength, independent of test parameters. Using linear regression analysis, empirical equations for predicting the maximum dynamic shear modulus from the static strength have been obtained for the three different soils
Unique gap structure and symmetry of the charge density wave in single-layer VSe
Single layers of transition metal dichalcogenides (TMDCs) are excellent
candidates for electronic applications beyond the graphene platform; many of
them exhibit novel properties including charge density waves (CDWs) and
magnetic ordering. CDWs in these single layers are generally a planar
projection of the corresponding bulk CDWs because of the quasi-two-dimensional
nature of TMDCs; a different CDW symmetry is unexpected. We report herein the
successful creation of pristine single-layer VSe, which shows a () CDW in contrast to the (4 4) CDW for the layers in
bulk VSe. Angle-resolved photoemission spectroscopy (ARPES) from the single
layer shows a sizable () CDW gap of 100 meV at the
zone boundary, a 220 K CDW transition temperature twice the bulk value, and no
ferromagnetic exchange splitting as predicted by theory. This robust CDW with
an exotic broken symmetry as the ground state is explained via a
first-principles analysis. The results illustrate a unique CDW phenomenon in
the two-dimensional limit
GENDER DIFFERENCE IN KNEE MOTION PATTERN DURING VERTICAL JUMP
Several factors have been proposed as contributors to increase the injuries rate on noncontact ACL rupture among female athletes. Altered movement pattern may results in increased incidence of non-contact ACL injuries for female athletes. Therefore, the purpose of this study was to compare the knee kinematics difference between male and female athletes. Eighteen athletes were participated in this study, including 10 male and 8 female. The Zebris 3 D ultrasound-based system was used to measurement the knee kinematics during vertical jump. The results were shown that there had significant difference in knee maximal flexion, internal rotation, and flexion angle at maximal knee abduction between male and female athlete during vertical jump. Female athletes had showed little change of flexion angle and internal rotation angle of knee during vertical jump
GENDER DIFFERENCE IN KNEE MOTION PATTERN DURING VERTICAL JUMP
Several factors have been proposed as contributors to increase the injuries rate on noncontact ACL rupture among female athletes. Altered movement pattern may results in increased incidence of non-contact ACL injuries for female athletes. Therefore, the purpose of this study was to compare the knee kinematics difference between male and female athletes. Eighteen athletes were participated in this study, including 10 male and 8 female. The Zebris 3 D ultrasound-based system was used to measurement the knee kinematics during vertical jump. The results were shown that there had significant difference in knee maximal flexion, internal rotation, and flexion angle at maximal knee abduction between male and female athlete during vertical jump. Female athletes had showed little change of flexion angle and internal rotation angle of knee during vertical jump
Phase-sensitive quantum effects in Andreev conductance of the SNS system of metals with macroscopic phase breaking length
The dissipative component of electron transport through the doubly connected
SNS Andreev interferometer indium (S)-aluminium (N)-indium (S) has been
studied. Within helium temperature range, the conductance of the individual
sections of the interferometer exhibits phase-sensitive oscillations of
quantum-interference nature. In the non-domain (normal) state of indium
narrowing adjacent to NS interface, the nonresonance oscillations have been
observed, with the period inversely proportional to the area of the
interferometer orifice. In the domain intermediate state of the narrowing, the
magneto-temperature resistive oscillations appeared, with the period determined
by the coherence length in the magnetic field equal to the critical one. The
oscillating component of resonance form has been observed in the conductance of
the macroscopic N-aluminium part of the system. The phase of the oscillations
appears to be shifted by compared to that of nonresonance oscillations.
We offer an explanation in terms of the contribution into Josephson current
from the coherent quasiparticles with energies of order of the Thouless energy.
The behavior of dissipative transport with temperature has been studied in a
clean normal metal in the vicinity of a single point NS contact.Comment: 9 pages, 7 figures, to be published in Low Temp. Phys., v. 29, No.
12, 200
Flavor symmetry analysis of charmless B --> VP decays
Based upon flavor SU(3) symmetry, we perform global fits to charmless
B decays into one pseudoscalar meson and one vector meson in the final
states. We consider different symmetry breaking schemes and find that the one
implied by na{\"i}ve factorization is slightly favored over the exact symmetry
case. The vertex of the unitarity triangle (UT)
constrained by our fits is consistent with other methods within errors. We have
found large color-suppressed, electroweak penguin and singlet penguin
amplitudes when the spectator quark ends up in the final-state vector meson.
Nontrivial relative strong phases are also required to explain the data. The
best-fit parameters are used to compute branching ratio and CP asymmetry
observables in all of the decay modes, particularly those in the decays
to be measured at the Tevatron and LHC experiments.Comment: 23 pages and 2 plots; updated with ICHEP'08 data and expanded in
discussions and reference
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