3,303 research outputs found
Distributions of the -matrix poles in Woods-Saxon and cut-off Woods-Saxon potentials
The positions of the -matrix poles are calculated in generalized
Woods-Saxon (GWS) potential and in cut-off generalized Woods-Saxon (CGWS)
potential. The solutions of the radial equations are calculated numerically for
the CGWS potential and analytically for GWS using the formalism of Gy. Bencze
\cite{[Be66]}. We calculate CGWS and GWS cases at small non-zero values of the
diffuseness in order to approach the square well potential and to be able to
separate effects of the radius parameter and the cut-off radius parameter. In
the case of the GWS potential the wave functions are reflected at the nuclear
radius therefore the distances of the resonant poles depend on the radius
parameter of the potential. In CGWS potential the wave function can be
reflected at larger distance where the potential is cut to zero and the
derivative of the potential does not exist. The positions of most of the
resonant poles do depend strongly on the cut-off radius of the potential, which
is an unphysical parameter. Only the positions of the few narrow resonances in
potentials with barrier are not sensitive to the cut-off distance. For the
broad resonances the effect of the cut-off can not be corrected by using a
suggested analytical form of the first order perturbation correction.Comment: Accepted by Nucl. Phys.
Values of inland fisheries in the Mekong river basin
Asia has the most productive inland fisheries in the world. The fishery sector contributes significantly to the national economies of the region. Inland fisheries also improve food security by providing a source of protein and a livelihood for millions of people in this part of the world, especially the rural poor. The purpose of this report is to provide information on the biological, economic, social and cultural values of river fisheries in the Lower Mekong Basin, and to identify the main impacts of environmental changes on these values. A review of fisheries-related literature, including project reports and gray literature, was undertaken. More than 800 documents were reviewed, and original information was extracted from 270 of them. The analysis identified a large number of localized studies leading to generic conclusions. The report addresses the basin wide issues and studies. It is then organized by nation, namely, the Chinese province of Yunnan, then Laos, Thailand, Cambodia and Vietnam. It first gives an overview of each country’s economic, fisheries and social situation, then details the values documented for river fisheries in each country
Values of inland fisheries in the Mekong river basin
This report provides an overview of the biological, economical, social and cultural values of river fisheries in the Lower Mekong Basin (Yunan, Laos, Thailand, Cambodia and Vietnam). The report also identifies the main impacts of environmental changes on these values.Inland fisheries, Socioeconomic aspects, Economic analysis, Asia, ISEW, Vietnam, Mekong River Delta, Mekong Delta,
J08069+1527: A newly discovered high amplitude, hybrid subdwarf B pulsator
We present our discovery of a new hybrid pulsating subdwarf B star,
J08069+1527. The effective temperature and surface gravity of 28,500400\,K
and 5.370.04\,dex, respectively, place this object inside the instability
strip and also among other pulsating hot subdwarfs of a hybrid nature, right
next to another fascinating star: Balloon\,090100001. From this proximity, we
anticipated this star could pulsate in both high and low frequency modes.
Indeed, our analysis of photometric data confirmed our prediction. We detected
two peaks in the high frequency region and two other peaks at low frequencies.
In addition, the amplitude of the dominant mode is very high and comparable to
the dominant peaks in other hybrid subdwarf B stars. Since this star is bright,
we performed time-series low resolution spectroscopy. Despite a low
signal-to-noise (S/N) ratio, we were able to detect the main peak from these
data. All our results strongly indicate that J08069+1527 is a high amplitude
pulsating hot subdwarf B star of hybrid nature. By analogy to the other
pulsating sdB star, we judge that the dominant mode we detected here has radial
nature. Future stellar modeling should provide us with quite good constrains as
p- and g-modes presented in this star are driven in different parts of its
interior.Comment: 7 pages, 10 figures, accepted for publication in MNRA
Calculating broad neutron resonances in a cut-off Woods-Saxon potential
In a cut-off Woods-Saxon (CWS) potential with realistic depth -matrix
poles being far from the imaginary wave number axis form a sequence where the
distances of the consecutive resonances are inversely proportional with the
cut-off radius value, which is an unphysical parameter. Other poles lying
closer to the imaginary wave number axis might have trajectories with irregular
shapes as the depth of the potential increases. Poles being close repel each
other, and their repulsion is responsible for the changes of the directions of
the corresponding trajectories. The repulsion might cause that certain
resonances become antibound and later resonances again when they collide on the
imaginary axis. The interaction is extremely sensitive to the cut-off radius
value, which is an apparent handicap of the CWS potential.Comment: 5 pages, 3 figure
RAT J0455+1305: A rare hybrid pulsating subdwarf B star
We present results on the second-faintest pulsating subdwarf B (sdB) star
known, RAT J0455+1305, derived from photometric data obtained in 2009. It shows
both short and long periods oscillations, theoretically assigned as pressure
and gravity modes. We identify six short-period frequencies (with one being a
combination) and six long-period frequencies. This star is the fourth hybrid
sdB star discovered so far which makes it of special interest as each type of
mode probes a different part of the star. This star is similar to the sdB
hybrid pulsator Balloon 090100001 in that it exhibits short-period mode
groupings, which can be used to identify pulsation parameters and constrain
theoretical models.Comment: published in MNRA
PHP51 Perception of Parallel Trade of Pharmaceuticals in Poland – Results of National Market Research
An entropy approach for diagnostic checking in time series analysis
It is a fact that a hydrological time series cannot be defined as a true model in practice. One of the important problems in stochastic hydrology is to determine the most appropriate model, and therefore modellers have certain flexibilities in exercising their subjective judgment in model identification. For this purpose, autocorrelation function [ACF], minimum residual variance [Min Var(e)], and Akaike Information Criterion [AIC- AICC-modified AIC- and FPE-final prediction error-] are widely used for testing the goodness of fit (model identification or diagnostic check) in time series modelling. The objective of this paper is to investigate diagnostic checking criteria, to compare their performance for linear autoregressive (AR) models, and to define a new entropy-based criterion (transinformation). In the presented study, observed and synthetic data sets are modelled and recognised criteria are evaluated in order to compare the diagnostic checking. All data sets are investigated for AR(1), AR(2), AR(3), ARMA(1,1) and ARMA(1,2) models which are mostly used in hydrology. The results showed that the performance of the transinformation criterion is superior to the other investigated diagnostic checking criteria
- …