11,408 research outputs found

    The Interaction of New and Old Magnetic Fluxes at the Beginning of Solar Cycle 23

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    The 11-year cycle of solar activity follows Hale's law by reversing the magnetic polarity of leading and following sunspots in bipolar regions during the minima of activity. In the 1996-97 solar minimum, most solar activity emerged in narrow longitudinal zones - `active longitudes' but over a range in latitude. Investigating the distribution of solar magnetic flux, we have found that the Hale sunspot polarity reversal first occurred in these active zones. We have estimated the rotation rates of the magnetic flux in the active zones before and after the polarity reversal. Comparing these rotation rates with the internal rotation inferred by helioseismology, we suggest that both `old' and `new' magnetic fluxes were probably generated in a low-latitude zone near the base of the solar convection zone. The reversal of active region polarity observed in certain longitudes at the beginning of a new solar cycle suggests that the phenomenon of active longitudes may give fundamental information about the mechanism of the solar cycle. The non-random distribution of old-cycle and new-cycle fluxes presents a challenge for dynamo theories, most of which assume a uniform longitudinal distribution of solar magnetic fields.Comment: 4 pages, 5 figures; accepted for publication in ApJ Letter

    A New Study of the Transition to Uniform Nuclear Matter in Neutron Stars and Supernovae

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    A comprehensive microscopic study of the properties of bulk matter at densities just below nuclear saturation ρs=2.5∌1014\rho_s = 2.5 \sim 10^{14} g cm−3^{-3}, zero and finite temperature and high neutron fraction, is outlined, and preliminary results presented. Such matter is expected to exist in the inner crust of neutron stars and during the core collapse of massive stars with $M \gtrsim 8M_{\odot}Comment: 4 pages, 2 figures. Participant Contribution at the ``Dense Matter in Heavy Ion Collisions and Astrophysics" Summer School, JINR, Dubna, Aug. 21 - Sept. 1, 2006. To be published in PEPAN letter

    General variational many-body theory with complete self-consistency for trapped bosonic systems

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    In this work we develop a complete variational many-body theory for a system of NN trapped bosons interacting via a general two-body potential. In this theory both the many-body basis functions {\em and} the respective expansion coefficients are treated as variational parameters. The optimal variational parameters are obtained {\em self-consistently} by solving a coupled system of non-eigenvalue -- generally integro-differential -- equations to get the one-particle functions and by diagonalizing the secular matrix problem to find the expansion coefficients. We call this theory multi-configurational Hartree for bosons or MCHB(M), where M specifies explicitly the number of one-particle functions used to construct the configurations. General rules for evaluating the matrix elements of one- and two-particle operators are derived and applied to construct the secular Hamiltonian matrix. We discuss properties of the derived equations. It is demonstrated that for any practical computation where the configurational space is restricted, the description of trapped bosonic systems strongly depends on the choice of the many-body basis set used, i.e., self-consistency is of great relevance. As illustrative examples we consider bosonic systems trapped in one- and two-dimensional symmetric and asymmetric double-well potentials. We demonstrate that self-consistency has great impact on the predicted physical properties of the ground and excited states and show that the lack of self-consistency may lead to physically wrong predictions. The convergence of the general MCHB(M) scheme with a growing number M is validated in a specific case of two bosons trapped in a symmetric double-well.Comment: 53 pages, 8 figure

    Tryptophane Metabolism X. The Effect Of Feeding 1(-)-, Dl-, And D(+)-Tryptophane, D(-)And Dl-(ÎČ-3-Indolelactic Acid,(ÎČ-3-Indolepyruvic Acid, And L(-)Kynurenine Upon The Storage Of Liver Glycogen And The Urinary Output Of Kynurenic Acid, Kynurenine, And Total Acetone Bodies

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    The amount of tryptophane required for maintenance and growth is small (2). When an excess is supplied to some animals, kynurenic acid is excreted (3) and, under certain conditions, kynurenine also (4). Although these are quantitatively the most important of the known metabolic products of tryptophane, the amounts excreted in extensive tests in the dog and rabbit have usually accounted for less than half, more often for less than a third, of the tryptophane administered (4-6)

    Tryptophane Metabolism X. The Effect Of Feeding 1(-)-, Dl-, And D(+)-Tryptophane, D(-)And Dl-(ÎČ-3-Indolelactic Acid,(ÎČ-3-Indolepyruvic Acid, And L(-)Kynurenine Upon The Storage Of Liver Glycogen And The Urinary Output Of Kynurenic Acid, Kynurenine, And Total Acetone Bodies

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    The amount of tryptophane required for maintenance and growth is small (2). When an excess is supplied to some animals, kynurenic acid is excreted (3) and, under certain conditions, kynurenine also (4). Although these are quantitatively the most important of the known metabolic products of tryptophane, the amounts excreted in extensive tests in the dog and rabbit have usually accounted for less than half, more often for less than a third, of the tryptophane administered (4-6)

    The Definition of Mach's Principle

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    Two definitions of Mach's principle are proposed. Both are related to gauge theory, are universal in scope and amount to formulations of causality that take into account the relational nature of position, time, and size. One of them leads directly to general relativity and may have relevance to the problem of creating a quantum theory of gravity.Comment: To be published in Foundations of Physics as invited contribution to Peter Mittelstaedt's 80th Birthday Festschrift. 30 page

    New bases for a general definition for the moving preferred basis

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    One of the challenges of the Environment-Induced Decoherence (EID) approach is to provide a simple general definition of the moving pointer basis or moving preferred basis. In this letter we prove that the study of the poles that produce the decaying modes in non-unitary evolution, could yield a general definition of the relaxation, the decoherence times, and the moving preferred basis. These probably are the most important concepts in the theory of decoherence, one of the most relevant chapters of theoretical (and also practical) quantum mechanics. As an example we solved the Omnes (or Lee-Friedrich) model using our theory.Comment: 6 page

    The Effect of Disfluency on the Framing Effect

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    This study investigated the framing effect and examined whether disfluency reduces susceptibility to framing. Prior work has shown that when information is presented in a fluent manner individuals process the content quickly, however when it is presented in a disfluent hard-to-read manner more analytical processing systems are activated. The current study examined the impact of fluency and dual process theory on framing susceptibility. Participants completed three classic decision problems (Asian Disease Problem, School Dropout Prevention Problem, and Fatal Disease Problem) with answers written in a risk seeking or risk averse manner and the font manipulated. The framing effect was again observed for these decision problems, but importantly was reduced in the disfluent conditions, as well as for participants more likely to use System 2 processes. These results suggest that simple font manipulations can have a powerful effect on decision making

    Fit Into College: A Program to Improve Physical Activity and Dietary Intake Lifestyles Among College Students

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    The purpose of this study was to determine whether a 10-week program could improve physical activity, physical fitness, body weight, dietary intake, and perceptions of exercise and diet among college 30 healthy college freshmen. Outcomes were measured at baseline, and following the 10-week program. The weekly sessions incorporated constructs of the Transtheoretical Model of Health Behavior Change and were administered by fitness interns who were junior or senior college students enrolled in health-related majors. The participants presented with low physical activity, physical fitness, and poor dietary intake, and 50% were overweight/obese (BMI \u3e 25). Participants demonstrated gains in their physical fitness and their perceived benefits to engaging in exercise and decreased their perceived barriers to engaging in exercise and a healthy diet. College freshmen presented with low levels of physical activity, poor dietary intake, and excess body weight. A peer-administered program can improve these measures and favorably change perceptions of exercise and diet
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