scholarly journals On the width of the Δ(1232) in NΔ and ΔΔ states

2019 ◽  
Vol 199 ◽  
pp. 02019
Author(s):  
Jouni A. Niskanen
Keyword(s):  
Angular Momentum ◽  
Kinetic Energy ◽  
Internal Energy ◽  
Pion Production ◽  
State Dependence ◽  
The State ◽  
Mesonic Decay

Due to the finite kinetic energy in the intermediate NΔ state the (internal) energy available for mesonic decay is decreased and consequently the effective NΔ width is suppressed in NN scattering. The same can happen also in ΔΔ case. Also the NΔ angular momentum suppresses the width as well, while the effect of the initial NN angular momentum is more subtle. The state dependence affects e.g. pion production observables and can also be seen as the origin of T = 1 “dibaryons”.

Mechanisms of the State Dependence of Wage Setting: Evidence from a Survey of Czech Firms

2017 ◽  
Vol 55 (4) ◽  
pp. 342-356
Author(s):  
Jan Babecký ◽  
Kamil Galuščák ◽  
Diana Žigraiová
Keyword(s):  
State Dependence ◽  
The State ◽  
Wage Setting

scholarly journals Consistent segregated staggered schemes with explicit steps for the isentropic and full Euler equations

2018 ◽  
Vol 52 (3) ◽  
pp. 893-944 ◽  
Author(s):  
Raphaèle Herbin ◽  
Jean-Claude Latché ◽  
Trung Tan Nguyen
Keyword(s):  
Energy Balance ◽  
Kinetic Energy ◽  
Internal Energy ◽  
Euler Equations ◽  
Left Hand ◽  
Isentropic Euler Equations ◽  
Space Discretization ◽  
Face Centered ◽  
The Stability ◽  
Stability And Consistency

In this paper, we build and analyze the stability and consistency of decoupled schemes, involving only explicit steps, for the isentropic Euler equations and for the full Euler equations. These schemes are based on staggered space discretizations, with an upwinding performed with respect to the material velocity only. The pressure gradient is defined as the transpose of the natural velocity divergence, and is thus centered. The velocity convection term is built in such a way that the solutions satisfy a discrete kinetic energy balance, with a remainder term at the left-hand side which is shown to be non-negative under a CFL condition. In the case of the full Euler equations, we solve the internal energy balance, to avoid the space discretization of the total energy, whose expression involves cell-centered and face-centered variables. However, since the residual terms in the kinetic energy balance (probably) do not tend to zero with the time and space steps when computing shock solutions, we compensate them by corrective terms in the internal energy equation, to make the scheme consistent with the conservative form of the continuous problem. We then show, in one space dimension, that, if the scheme converges, the limit is indeed an entropy weak solution of the system. In any case, the discretization preserves by construction the convex of admissible states (positivity of the density and, for Euler equations, of the internal energy), under a CFL condition. Finally, we present numerical results which confort this theory.

Photochemistry of van der Waals Complexes and Small Clusters

1996 ◽  
Author(s):  
C. Jouvet ◽  
D. Solgadi
Keyword(s):  
Kinetic Energy ◽  
Potential Energy ◽  
Potential Energy Surface ◽  
Internal Energy ◽  
Energy Surface ◽  
Van Der Waals ◽  
Van Der Waals Complexes ◽  
Small Subset ◽  
Energy Effect ◽  
Precise Control

In a chemical reaction, the shape of the potential energy surface (PES) dictates the reaction rate and energy disposal in the products. Not only does the dynamics depend crucially upon the features of the surface, but, ultimately one seeks to influence the course of the reaction by preparing selectively certain regions of the surface. For harpooning reactions, the propensity rules for energy disposal in the products (influence of the entrance kinetic energy, effect of the early or late barrier) have been established by Polanyi (1972) and have been used later as guidelines. Here, the surface may easily be modeled in simple terms using long-range electrostatic interaction in the entrance valley. There was, then, need of an experimental method which allows the possibility of observing directly the characteristic regions of this potential energy surface, but also to investigate precisely the surface in other types of reaction. The study of the reactivity of van der Waals complexes is intended to fulfil this purpose. In classical experiments, the surface is obtained by inversion of the experimental data which are differential cross sections and internal energy distribution of the products. This procedure is difficult and not unambiguous. The first step is to determine the correlation between the entrance channel's parameters (kinetic energy, internal energy, angular momentum) and the final states of the products (kinetic energy, internal energy, angular distribution). This requires a precise control of the entrance channel. Therefore, the goal of many experiments is to reduce the initial states to a small subset, and to measure the energy disposal in the products with the greatest accuracy. This was first achieved by controlling the kinetic energy of the reactants in crossed beam experiments. Later, a certain control of the collision geometry was obtained by orienting the molecules or the atomic orbitals in crossed beam experiments or by using prealigned systems in a van der Waals complex: this subject is discussed in Buelow et al. (1986).

scholarly journals On the Loss of Angular Momentum from Stars in the Pre-Main Sequence Phase

1970 ◽  
Vol 4 ◽  
pp. 73-81
Author(s):  
Isao Okamoto
Keyword(s):  
Magnetic Field ◽  
Angular Momentum ◽  
Main Sequence ◽  
Magnetic Energy ◽  
Rotational Velocity ◽  
The State ◽  
Rotational Instability ◽  
Stellar Rotation ◽  
Initial State ◽  
Initial Magnetic Field

AbstractThe braking of stellar rotation in the wholly convective phase in the pre-main sequence is numerically discussed. The structure of stars in that phase is expressed by a rotating polytrope with an index of 1.5 and the Schatzman-type mechanism is used as the means of loss of angular momentum. The magnetic energy is assumed to change with evolution as H02/8π(R/R0)s, where H0 and R0 are initial magnetic field and radius, and s is a free parameter. The changes of angular momentum, rotational velocity, etc. with contraction are calculated from the initial state, which is taken to be the state when the stars flared up to the Helmholtz-Kelvin contraction. It is shown that the exponent s must be in the range from – 1 to – 3 so that the stars with adequate strength of the initial magnetic field may lose almost all of their angular momenta in a suitable rate if they are initially in the state of rotational instability.Stellar rotation from the time of star formation to the main sequence stage is discussed. Also, the formation of the solar system and other planetary systems is discussed, with respect to the braking.

Labour supply dynamics at the extensive and intensive margins of the UK men and women

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Lixin Cai
Keyword(s):  
Labour Supply ◽  
Labour Force ◽  
State Dependence ◽  
Labour Force Participation ◽  
Tobit Model ◽  
The State ◽  
Individual Heterogeneity ◽  
Content Type ◽  
Extensive And Intensive Margins ◽  
The Uk

PurposeThe purpose of this study is to enhance understanding labour supply dynamics of the UK workers by examining whether and to what extent there is state dependence in the labour supply at both the extensive and intensive margins.Design/methodology/approachA dynamic two-tiered Tobit model is applied to the first seven waves of Understanding Society: the UK Household Longitudinal Study. The model used accounts for observed and unobserved individual heterogeneity and serially correlated transitory shocks to labour supply to draw inferences on state dependence.FindingsThe results show that both observed and unobserved individual heterogeneity contributes to observed inter-temporal persistence of the labour supply of the UK workers, and the persistence remains after these factors are controlled for, suggesting true state dependence at both the extensive and intensive margins of the labour supply. The study also finds that at both the margins, the state dependence of labour supply is larger for females than for males and that for both genders the state dependence is larger for people with low education, mature aged workers and people with long-standing illness or impairment. The results also show that estimates from a conventional Tobit model may produce misleading inferences regarding labour supply at the extensive and intensive margins.Originality/valueThis study adds to the international literature on labour supply dynamics by providing empirical evidence for both the extensive and intensive margins of labour supply, while previous studies tend to focus on the extensive margin of labour force participation only. Also, unlike earlier studies that often focus on females, this study compares labour supply dynamics between males and females. The study also compares the estimates from the more flexible two-tiered Tobit model with that from the conventional Tobit model.

scholarly journals Long-Term Analysis of Atmospheric Energetics Components over the Mediterranean, Middle East and North Africa

Atmosphere ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 976
Author(s):  
Silas Michaelides
Keyword(s):  
Middle East ◽  
Kinetic Energy ◽  
Energy Conversion ◽  
Internal Energy ◽  
North Africa ◽  
Climatic Data ◽  
Monthly Means ◽  
Seasonal Behavior ◽  
Long Term Changes

In this research, one aspect of the climate that is not commonly referred to, namely, the long-term changes in the components of the atmospheric energy, is investigated. In this respect, the changes in four energy forms are considered, namely, Kinetic Energy (KE), Thermal Energy (TE), Internal Energy (IE), Potential Energy (PE) and Latent Energy (LE); the Energy Conversion (EC) between Kinetic Energy and Potential plus Internal Energy (PIE) is also considered. The area considered in this long-term energetics analysis covers the entire Mediterranean basin, the Middle East and a large part of North Africa. This broad geographical area has been identified by many researchers as a hot spot of climate change. Analyses of climatic data have indeed shown that this region has been experiencing marked changes regarding several climatic variables. The present energetics analysis makes use of the ERA-Interim database for the period from 1979 to 2018. In this 40-year period, the long-term changes in the above energetics components are studied. The monthly means of daily means for all the above energy forms and Energy Conversion comprise the basis for the present research. The results are presented in the form of monthly means, annual means and spatial distributions of the energetics components. They show the dominant role of the subtropical jet-stream in the KE regime. During the study period, the tendency is for KE to decrease with time, with this decrease found to be more coherent in the last decade. The tendency for TE is to increase with time, with this increase being more pronounced in the most recent years, with the maximum in the annual mean in KE noted in 2015. The sum of Potential and Internal energies (PIE) and the sum of Potential, Internal and Latent energies (PILE) follow closely the patterns established for TE. In particular, the strong seasonal influence on the monthly means is evident with minima of PIE and PILE noted in winters, whereas, maxima are registered during summers. In addition, both PIE and PILE exhibit a tendency to increase with time in the 40-year period, with this increase being more firmly noted in the more recent years. Although local conversion from KE into PIE is notable, the area averaging of EC shows that the overall conversion is in the direction of increasing the PIE content of the area at the expense of the KE content. EC behaves rather erratically during the study period, with values ranging from 0.5 to 3.7 × 102 W m−2. Averaged over the study area, the Energy Conversion term operates in the direction of converting KE into PIE; it also lacks a seasonal behavior.

scholarly journals Magnetic Field Amplification and Polar Jet Formation in Protostars

1987 ◽  
Vol 115 ◽  
pp. 384-384
Author(s):  
S. Hinata
Keyword(s):  
Magnetic Field ◽  
Angular Momentum ◽  
Kinetic Energy ◽  
Accretion Disk ◽  
Outer Edge ◽  
Moment Of Inertia ◽  
Simple Relationship ◽  
Field Amplification ◽  
Background Magnetic Field ◽  
The Moment

There is a simple relationship among moment of inertia I, rotational kinetic energy K, and momentum L given by (David Layzer, private communication), 2IK ≧ L. During the Hayashi phase a rotating protostar will amplify the trapped magnetic field by a dynamo-like process. Since the rotation is expected to be fast, many unstable modes will be excited and will grow exponentially in time until some nonlinear processes saturate the amplitude. However, it may happen that the reduction in rotational kinetic energy becomes so large that without increasing the moment of inertia the inequality given above may not be satisfied. The only way to increase the moment of inertia is to move the mass outward. This can be done by transferring the angular momentum outward through the magnetic field. So we will have a fast rotating mass shell at the outer edge of the star. Further transfer of angular momentum will push the shell against the accretion disk; the moving masses of the disk will divert the mass flow along the background magnetic field which extends perpendicular to the accretion disk. This results in the hollow cone jets from both poles because the outward motion is primarily on the equatorial plane.

scholarly journals Ionisationsquerschnitt von OV gegenüber Elektronenstoß unter teilweiser Berücksichtigung des Austauschs

1961 ◽  
Vol 16 (6) ◽  
pp. 583-598 ◽  
Author(s):  
F. B. Malik ◽  
E. Trefftz
Keyword(s):  
Angular Momentum ◽  
Kinetic Energy ◽  
Cross Section ◽  
Ionization Energy ◽  
Total Angular Momentum ◽  
Ionization Cross Section ◽  
Wave Method ◽  
Distorted Wave ◽  
Ionization Cross ◽  
Distorted Wave Method

The ionization cross-section of highly ionized oxygen, O4+, is calculated according to the “distorted-wave” method. Exchange between the scattered and the ejected electron is taken into account as far as it is of long range nature. It is shown that contributions of high total angular momentum L are essential, L=0 giving only 3% of the total cross-section. This result should qualitatively be the same for all highly ionized atoms, whereas the following seems to be a special feature of O V ionization: for energies around twice the ionization energy the contributions of the optically allowed transitions of the ejected electron (angular momentum lej=1) are relatively small. The contributions of lej =0, 1, 2 and 3 are about 16%, 18%, 24% and 19% respectively for E=20.13.6 eV=2.39 × Ionization energy. The maximum cross section is 0.112 at. u. = 0.31 ·10-18 cm2 for electrons of 310 eV kinetic energy (2.8 × ionization energy). It is about twice as large as given by the ELWERT formula.

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