92 research outputs found
Investigations of the pi N total cross sections at high energies using new FESR: log nu or (log nu)^2
We propose to use rich informations on pi p total cross sections below N= 10
GeV in addition to high-energy data in order to discriminate whether these
cross sections increase like log nu or (log nu)^2 at high energies, since it is
difficult to discriminate between asymptotic log nu and (log nu)^2 fits from
high-energy data alone. A finite-energy sum rule (FESR) which is derived in the
spirit of the P' sum rule as well as the n=1 moment FESR have been required to
constrain the high-energy parameters. We then searched for the best fit of pi p
total cross sections above 70 GeV in terms of high-energy parameters
constrained by these two FESR. We can show from this analysis that the (log
nu)^2 behaviours is preferred to the log nu behaviours.Comment: to be published in Phys. Rev. D 5 pages, 2 eps figure
Spectral Duality in Integrable Systems from AGT Conjecture
We describe relationships between integrable systems with N degrees of
freedom arising from the AGT conjecture. Namely, we prove the equivalence
(spectral duality) between the N-cite Heisenberg spin chain and a reduced gl(N)
Gaudin model both at classical and quantum level. The former one appears on the
gauge theory side of the AGT relation in the Nekrasov-Shatashvili (and further
the Seiberg-Witten) limit while the latter one is natural on the CFT side. At
the classical level, the duality transformation relates the Seiberg-Witten
differentials and spectral curves via a bispectral involution. The quantum
duality extends this to the equivalence of the corresponding Baxter-Schrodinger
equations (quantum spectral curves). This equivalence generalizes both the
spectral self-duality between the 2x2 and NxN representations of the Toda chain
and the famous AHH duality
Catalysis and rotation of F-1 motor: Cleavage of ATP at the catalytic site occurs in 1 ms before 40 degrees substep rotation
F-1, a water-soluble portion of FoF1-ATP synthase, is an ATIP hydrolysis-driven rotary motor. The central gamma-subunit rotates in the alpha(3)beta(3) cylinder by repeating the following four stages of rotation: ATP-binding dwell, rapid 801 substep rotation, interim dwell, and rapid 40degrees substep rotation. At least two 1-ms catalytic events occur in the interim dwell, but it is still unclear which steps in the ATPase cycle, except for ATIP binding, correspond to these events. To discover which steps, we analyzed rotations of F-1 subcomplex (alpha(3)beta(3)gamma) from thermophilic Bacillus PS3 under conditions where cleavage of ATIP at the catalytic site is decelerated: hydrolysis of ATP by the catalytic-site mutant F, and hydrolysis of a slowly hydrolyzable substrate ATPgammaS (adenosine 5'-[gamma-thio]triphosphate) by wild-type F-1. In both cases, interim dwells were extended as expected from bulk phase kinetics, confirming that cleavage of ATP takes place during the interim dwell. Furthermore, the results of ATPgammaS hydrolysis by the mutant F-1 ensure that cleavage of ATIP most likely corresponds to one of the two 1-ms events and not some other faster undetected event. Thus, cleavage of ATP on F-1 occurs in 1 ms during the interim dwell, and we call this interim dwell catalytic dwell
Direct Observation of the Myosin Va Recovery Stroke That Contributes to Unidirectional Stepping along Actin
Myosins are ATP-driven linear molecular motors that work as cellular force
generators, transporters, and force sensors. These functions are driven by
large-scale nucleotide-dependent conformational changes, termed
“strokes”; the “power stroke” is the force-generating
swinging of the myosin light chain–binding “neck” domain
relative to the motor domain “head” while bound to actin; the
“recovery stroke” is the necessary initial motion that primes, or
“cocks,” myosin while detached from actin. Myosin Va is a processive
dimer that steps unidirectionally along actin following a “hand over
hand” mechanism in which the trailing head detaches and steps forward
∼72 nm. Despite large rotational Brownian motion of the detached head about
a free joint adjoining the two necks, unidirectional stepping is achieved, in
part by the power stroke of the attached head that moves the joint forward.
However, the power stroke alone cannot fully account for preferential forward
site binding since the orientation and angle stability of the detached head,
which is determined by the properties of the recovery stroke, dictate actin
binding site accessibility. Here, we directly observe the recovery stroke
dynamics and fluctuations of myosin Va using a novel, transient caged
ATP-controlling system that maintains constant ATP levels through stepwise
UV-pulse sequences of varying intensity. We immobilized the neck of monomeric
myosin Va on a surface and observed real time motions of bead(s) attached
site-specifically to the head. ATP induces a transient swing of the neck to the
post-recovery stroke conformation, where it remains for ∼40 s, until ATP
hydrolysis products are released. Angle distributions indicate that the
post-recovery stroke conformation is stabilized by ≥5
kBT of energy. The high kinetic
and energetic stability of the post-recovery stroke conformation favors
preferential binding of the detached head to a forward site 72 nm away. Thus,
the recovery stroke contributes to unidirectional stepping of myosin Va
The practice of child and adolescent psychiatry: a survey of early-career psychiatrists in Japan
<p>Abstract</p> <p>Background</p> <p>Child and adolescent psychiatry (CAP), a subspecialty of psychiatry in Japan, is facing a serious workforce shortage. To resolve this situation, the Japanese government has organized a task force and has been working to increase psychiatrists' clinical skills to improve care for children and adolescents with mental health problems. Using an online questionnaire system, the authors have conducted a survey to investigate the perceptions, experiences, and interests of early-career psychiatrists in CAP.</p> <p>Methods</p> <p>The subjects of this study were 182 psychiatrists in Japan whose individual clinical experiences did not exceed 15 years. The authors of this study created an online questionnaire system and e-mailed the URL and login password to all subjects. Respondents anonymously answered the questions. Most questions required an answer indicating a level of agreement scored on a nine-point scale. Responding to the questionnaire was considered to constitute consent, and all respondents' privacy was carefully protected.</p> <p>Results</p> <p>The mean age and clinical psychiatric experience of the subjects were found to be 33.1 ± 4.5 years and 5.43 ± 3.5 years, respectively. On a nine-point scale (with nine being the highest), experience and interest in CAP measured 3.05 ± 1.9 and 5.34 ± 2.5, respectively; further, these two factors showed significant correlation (r = 0.437, p < 0.0001). The mean score for the early-career psychiatrists' confidence in their ability to diagnose and appropriately treat was notably low, at 3.13 ± 1.9.</p> <p>Conclusion</p> <p>Our results demonstrated that early-career psychiatrists self-evaluated their CAP clinical experience as insufficient, and these clinicians' CAP experiences and interests correlated significantly. Therefore, in order to improve child and adolescent medical care, we need to expose young psychiatrists to sufficient CAP cases and explore the factors that could attract them to this field.</p
Hawking Radiation and Tunneling Mechanism for a New Class of Black Holes in Einstein-Gauss-Bonnet Gravity
We study the Hawking radiation in a new class of black hole solutions in the
Einstein-Gauss-Bonnet theory. The black hole has been argued to have vanishing
mass and entropy, but finite Hawking temperature. To check if it really emits
radiation, we analyse the Hawking radiation using the original method of
quantization of scalar field in the black hole background and the quantum
tunneling method, and confirm that it emits radiation at the Hawking
temperature. A general formula is derived for the Hawking temperature and
backreaction in the tunneling approach. Physical implications of these results
are discussed.Comment: 12 pages, v2: Title slightly changed. Motivation and discussions are
elaborated, v3: typos corrected to match the published versio
Association of lower limb muscle mass and energy expenditure with visceral fat mass in healthy men
M5-branes, toric diagrams and gauge theory duality
In this article we explore the duality between the low energy effective
theory of five-dimensional N=1 SU(N)^{M-1} and SU(M)^{N-1} linear quiver gauge
theories compactified on S^1. The theories we study are the five-dimensional
uplifts of four-dimensional superconformal linear quivers. We study this
duality by comparing the Seiberg-Witten curves and the Nekrasov partition
functions of the two dual theories. The Seiberg-Witten curves are obtained by
minimizing the worldvolume of an M5-brane with nontrivial geometry. Nekrasov
partition functions are computed using topological string theory. The result of
our study is a map between the gauge theory parameters, i.e., Coulomb moduli,
masses and UV coupling constants, of the two dual theories. Apart from the
obvious physical interest, this duality also leads to compelling mathematical
identities. Through the AGTW conjecture these five-dimentional gauge theories
are related to q-deformed Liouville and Toda SCFTs in two-dimensions. The
duality we study implies the relations between Liouville and Toda correlation
functions through the map we derive.Comment: 58 pages, 17 figures; v2: minor corrections, references adde
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