8,892 research outputs found
Modified Bethe-Weizsacker mass formula with isotonic shift and new driplines
Nuclear masses are calculated using the modified Bethe-Weizsacker mass
formula in which the isotonic shifts have been incorporated. The results are
compared with the improved liquid drop model with isotonic shift. Mass excesses
predicted by this method compares well with the microscopic-macroscopic model
while being much more simple. The neutron and proton drip lines have been
predicted using this modified Bethe-Weizsacker mass formula with isotonic
shifts.Comment: 9 pages including 2 figure
Flow properties of driven-diffusive lattice gases: theory and computer simulation
We develop n-cluster mean-field theories (0 < n < 5) for calculating the flow
properties of the non-equilibrium steady-states of the Katz-Lebowitz-Spohn
model of the driven diffusive lattice gas, with attractive and repulsive
inter-particle interactions, in both one and two dimensions for arbitrary
particle densities, temperature as well as the driving field. We compare our
theoretical results with the corresponding numerical data we have obtained from
the computer simulations to demonstrate the level of accuracy of our
theoretical predictions. We also compare our results with those for some other
prototype models, notably particle-hopping models of vehicular traffic, to
demonstrate the novel qualitative features we have observed in the
Katz-Lebowitz-Spohn model, emphasizing, in particular, the consequences of
repulsive inter-particle interactions.Comment: 12 RevTex page
Collective traffic-like movement of ants on a trail: dynamical phases and phase transitions
The traffic-like collective movement of ants on a trail can be described by a
stochastic cellular automaton model. We have earlier investigated its unusual
flow-density relation by using various mean field approximations and computer
simulations. In this paper, we study the model following an alternative
approach based on the analogy with the zero range process, which is one of the
few known exactly solvable stochastic dynamical models. We show that our theory
can quantitatively account for the unusual non-monotonic dependence of the
average speed of the ants on their density for finite lattices with periodic
boundary conditions. Moreover, we argue that the model exhibits a continuous
phase transition at the critial density only in a limiting case. Furthermore,
we investigate the phase diagram of the model by replacing the periodic
boundary conditions by open boundary conditions.Comment: 8 pages, 6 figure
Dust-acoustic rogue waves in an electron depleted plasma
A rigorous theoretical investigation is made to study the characteristics of
dust-acoustic (DA) waves (DAWs) in an electron depleted unmagnetized opposite
polarity dusty plasma system that contains super-thermal (-distributed)
ions, mobile positively and negatively charged dust grains for the first time.
The reductive perturbation method is employed to obtain the NLSE to explore the
modulational instability (MI) conditions for DAWs as well as the formation and
characteristics of gigantic rogue waves. The nonlinear and dispersion
properties of the dusty plasma medium are the prime reasons behind the
formation of rogue waves. The height and thickness of the DARWs associated with
DAWs as well as the MI conditions of DAWs are numerically analyzed by changing
different dusty plasma parameters, such as dust charges, dust and ion number
densities, and ion-temperature, etc. The implications of the results for
various space dusty plasma systems (viz., mesosphere, F-rings of Saturn, and
cometary atmosphere, etc.) as well as laboratory dusty plasma produced by
laser-matter interaction are briefly mentioned.Comment: 6 figures; 6 page
Exact density profiles for fully asymmetric exclusion process with discrete-time dynamics
Exact density profiles in the steady state of the one-dimensional fully
asymmetric simple exclusion process on semi-infinite chains are obtained in the
case of forward-ordered sequential dynamics by taking the thermodynamic limit
in our recent exact results for a finite chain with open boundaries. The
corresponding results for sublattice parallel dynamics follow from the
relationship obtained by Rajewsky and Schreckenberg [Physica A 245, 139 (1997)]
and for parallel dynamics from the mapping found by Evans, Rajewsky and Speer
[J. Stat. Phys. 95, 45 (1999)]. By comparing the asymptotic results appropriate
for parallel update with those published in the latter paper, we correct some
technical errors in the final results given there.Comment: About 10 pages and 3 figures, new references are added and a
comparison is made with the results by de Gier and Nienhuis [Phys. Rev. E 59,
4899(1999)
Prognostic significance of histopathological response to preoperative chemotherapy in unilateral Wilms' tumor: An analysis of 899 patients treated on the SIOP WT 2001 protocol in the UK-CCLG and GPOH studies
In the SIOP Wilms' tumor (WT) studies, preoperative chemotherapy is used as primary treatment, and tumors are classified thereafter by pathologists. Completely necrotic WTs (CN-WTs) are classified as low-risk tumors. The aim of the study was to evaluate whether a subset of regressive type WTs (RT-WTs) (67%-99% chemotherapy-induced changes [CIC]) showing an exceptionally good response to preoperative chemotherapy had comparably excellent survivals as CN-WTs, and to establish a cut-off point of CIC that could define this subset. The study included 2117 patients with unilateral, nonanaplastic WTs from the UK-CCLG and GPOH-WT studies (2001-2020) treated according to the SIOP-WT-2001 protocol. There were 126 patients with CN-WTs and 773 with RT-WTs, stages I-IV. RT-WTs were subdivided into subtotally necrotic WTs (>95% CIC) (STN-WT96-99) (124 patients) and the remaining of RT-WT (RR-WT67-95) (649 patients). The 5-year event-free survival (EFS) and overall survival (OS) for CN-WTs were 95.3% (±2.1% SE) and 97.3% (±1.5% SE), and for RT-WTs 85.7% (±1.14% SE, P < .01) and 95.2% (±0.01% SE, P = .59), respectively. CN-WT and STN-WT96-99 groups showed significantly better EFS than RR-WT67-95 (P = .003 and P = .02, respectively), which remained significantly superior when adjusted for age, local stage and metastasis at diagnosis, in multivariate analysis, whereas OS were superimposable (97.3 ± 1.5% SE for CN-WT; 97.8 ± 1.5% SE for STN-WT96-99; 94.7 ± 1.0% SE for RR-WT67-95). Patients with STN-WT96-99 share the same excellent EFS and OS as patients with CN-WTs, and although this was achieved by more treatment for patients with STN-WT96-99 than for patients with CN-WT, reduction in postoperative treatment of these patients may be justified
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