12,314 research outputs found
Nilsson diagrams for light neutron-rich nuclei with weakly-bound neutrons
Using Woods-Saxon potentials and the eigenphase formalism for one-particle
resonances, one-particle bound and resonant levels for neutrons as a function
of quadrupole deformation are presented, which are supposed to be useful for
the interpretation of spectroscopic properties of some light neutron-rich
nuclei with weakly-bound neutrons. Compared with Nilsson diagrams in text books
which are constructed using modified oscillator potentials, we point out a
systematic change of the shell structure in connection with both weakly-bound
and resonant one-particle levels related to small orbital angular momenta
. Then, it is seen that weakly-bound neutrons in nuclei such as
C and Mg may prefer to being deformed as a result of
Jahn-Teller effect, due to the near degeneracy of the 1d-2s
levels and the 1f-2p levels in the spherical potential,
respectively. Furthermore, the absence of some one-particle resonant levels
compared with the Nilsson diagrams in text books is illustrated.Comment: 12 pages, 5 figure
Effect of surface roughness on the microwave emission from soils
The effect of surface roughness on the brightness temperature of a moist terrain was studied through the modification of Fresnel reflection coefficient and using the radiative transfer equation. The modification involves introduction of a single parameter to characterize the roughness. It is shown that this parameter depends on both the surface height variance and the horizontal scale of the roughness. Model calculations are in good quantitative agreement with the observed dependence of the brightness temperature on the moisture content in the surface layer. Data from truck mounted and airborne radiometers are presented for comparison. The results indicate that the roughness effects are greatest for wet soils where the difference between smooth and rough surfaces can be as great as 50K
Antibound States and Halo Formation in the Gamow Shell Model
The open quantum system formulation of the nuclear shell model, the so-called
Gamow Shell Model (GSM), is a multi-configurational SM that employs a
single-particle basis given by the Berggren ensemble consisting of Gamow states
and the non-resonant continuum of scattering states. The GSM is of particular
importance for weakly bound/unbound nuclear states where both many-body
correlations and the coupling to decay channels are essential. In this context,
we investigate the role of l=0 antibound (virtual) neutron single-particle
states in the shell model description of loosely bound wave functions, such as
the ground state wave function of a halo nucleus 11Li
Competition for herbage by Phaulacridium vittatum (Sjostedt) (Orthoptera:Acrididae) and sheep during summer drought
Mechanism of NSF: New evidence challenging the prevailing theory
Nephrogenic systemic fibrosis (NSF) has been associated with the administration of gadolinium-based contrast agents in patients with severely impaired renal function (SIRF), endstage renal disease (ESRD), or acute renal failure (ARF). Since the vast majority of these patients do not get NSF, it is highly likely that patient factors play a role in its development. Although free or dechelated gadolinium is thought by some to be the only trigger of NSF, recent evidence suggests that chelated gadolinium may be important. Chelated gadolinium such as Omniscan (gadodiamide) and Magnevist (gadopentetate) can directly stimulate macrophages and monocytes in vitro to release profibrotic cytokines and growth factors capable of initiating and supporting the tissue fibrosis that is characteristic of NSF. In addition, an effect of chelated gadolinium on fibroblasts has also been demonstrated. Chelated gadolinium in the form of Omniscan, Magnevist, MultiHance, and ProHance increased proliferation of human dermal fibroblasts. Indeed, increased numbers of macrophages, together with activated fibroblasts and fibrocytes, are essential cells in the fibrotic process and are present in NSF skin. Accordingly, it is important that chelated gadolinium, in combination with patient cofactors, is considered in the etiology of NSF associated with enhanced scans
Is it a norm to favour your own group?
This paper examines the relationship between norm enforcement and in-group favouritism behaviour. Using a new two-stage allocation experiment with punishments, we investigate whether in-group favouritism is considered as a social norm in itself or as a violation of a different norm, such as egalitarian norm. We find that which norm of behaviour is enforced depends on who the punisher is. If the punishers belong to the in-group, in-group favouritism is considered a norm and it does not get punished. If the punishers belong to the outgroup, in-group favouritism is frequently punished. If the punishers belong to no group and merely observe ingroup favouritism (the third-party), they do not seem to care sufficiently to be willing to punish this behaviour. Our results shed a new light on the effectiveness of altruistic norm enforcement when group identities are taken into account and help to explain why in-group favouritism is widespread across societies.This is the accepted manuscript. The final publication is available from Springer via http://dx.doi.org/10.1007/s10683-014-9417-9
Generic Constraints on the Relativistic Mean-Field and Skyrme-Hartree-Fock Models from the Pure Neutron Matter Equation of State
We study the nuclear symmetry energy S(rho) and related quantities of nuclear
physics and nuclear astrophysics predicted generically by relativistic
mean-field (RMF) and Skyrme-Hartree-Fock (SHF) models. We establish a simple
prescription for preparing equivalent RMF and SHF parametrizations starting
from a minimal set of empirical constraints on symmetric nuclear matter,
nuclear binding energy and charge radii, enforcing equivalence of their Lorenz
effective masses, and then using the pure neutron matter (PNM) equation of
state (EoS) obtained from ab-initio calculations to optimize the pure isovector
parameters in the RMF and SHF models. We find the resulting RMF and SHF
parametrizations give broadly consistent predictions of the symmetry energy J
and its slope parameter L at saturation density within a tight range of <~2 MeV
and <~6 MeV respectively, but that clear model dependence shows up in the
predictions of higher-order symmetry energy parameters, leading to important
differences in (a) the slope of the correlation between J and L from the
confidence ellipse, (b) the isospin-dependent part of the incompressibility of
nuclear matter K_tau, (c) the symmetry energy at supra-saturation densities,
and (d) the predicted neutron star radii. The model dependence can lead to
about 1-2 km difference in predictions of the neutron star radius given
identical predicted values of J, L and symmetric nuclear matter (SNM)
saturation properties. Allowing the full freedom in the effective masses in
both models leads to constraints of 30<~J<~31.5 MeV, 35<~L<~60 MeV,
-330<~K_tau<~-216 MeV for the RMF model as a whole and 30<~J<~33 MeV, 28<~L<~65
MeV, -420<~K_tau<~-325 MeV for the SHF model as a whole. Notably, given PNM
constraints, these results place RMF and SHF models as a whole at odds with
some constraints on K_tau inferred from giant monopole resonance and neutron
skin experimental results.Comment: 15 pages, 7 figures, 4 table
Full transmission within a wide energy range and super-criticality in relativistic barrier scattering
For potential barriers with scalar and vector coupling, we show that a Dirac
particle could experience nearly full transmission within a wide sub-barrier
energy band. Moreover, for certain potential configurations, including
pseudo-spin symmetry where the scalar potential is the negative of the vector,
full transmission occurs for arbitrarily small momentum.Comment: 10 pages, 4 figures, 1 table, 1 video animatio
Improving Thermal Energy Performance of UK Built Environment through the Use of Shading Devices
Comparison of Real-world Data with Simulated Results to Enhance Building Thermal Retention when using Shading Devices
Managing thermal loss is a key topic that needs further investigation as it has a direct link to reducing the energy load in buildings. One of these thermal loss management methods can be the use of shading devices. Dynamic thermal models normally used at the early stages of the building design can play an important role in the decisionmaking process regarding the use of shading devices. This paper presents the results of a real-world study assessing the potential of using a sealed cellular blind as a passive energy conservation method, where the real-world results are compared with the simulated results generated with EDSL Tas. During the real-world study, a positive impact of having blinds was seen whereby the window surface temperature increased and office heating energy consumption was lowered. EDSL Tas was able to predict a similar trend of results for the window surface temperature but not for the energy consumption. This was mainly due to the inability of the software in demonstrating the effect of infiltration of the blind
- …