Quantitative analysis of pedestrian counterflow in a cellular automaton model

Pedestrian dynamics exhibits various collective phenomena. Here we study bidirectional pedestrian flow in a floor field cellular automaton model. Under certain conditions, lane formation is observed. Although it has often been studied qualitatively, e.g., as a test for the realism of a model, there are almost no quantitative results, neither empirically nor theoretically. As basis for a quantitative analysis we introduce an order parameter which is adopted from the analysis of colloidal suspensions. This allows to determine a phase diagram for the system where four different states (free flow, disorder, lanes, gridlock) can be distinguished. Although the number of lanes formed is fluctuating, lanes are characterized by a typical density. It is found that the basic floor field model overestimates the tendency towards a gridlock compared to experimental bounds. Therefore an anticipation mechanism is introduced which reduces the jamming probability.Comment: 11 pages, 12 figures, accepted for publication in Phys. Rev.

L-ASPARAGINASE INDUCED HYPOFIBRINOGENEMIA: A CASE REPORT

Anticancer therapy is always known to cause various side effects. L-asparaginase used in the treatment of adult T-cell lymphoblastic leukemia is anovel class of drug, an enzyme produced from plants as well as microorganisms except human. It is known to cause various adverse reactions including life-threatening neurological complications and thrombotic disorders. Hence, we report a case of hypofibrinogenemia associated with L-asparaginase in a patient treated for T-cell adult lymphoblastic leukemia.Â

GEMCITABINE INDUCED DROP IN PLATELET COUNTS: A CASE REPORT

Chemotherapy with anticancer drugs is known to be beneficial, but like a double-edged sword it as its own demerits in form of adverse effects. Cancer chemotherapy induced thrombocytopenia is troublesome and platin based regimens namely Carboplatin and Cisplatin is known to cause it very commonly. Gemcitabine, in combination with platinum compounds is known to cause severe thrombocytopenia. Hence, we report a case of thrombocytopenia induced by Gemcitabine when used as single agent in treatment of ovarian cancer.Â

Pelvic lymphadenectomy as a component of interval cytoreduction for ovarian cancer: is there a benefit? A pilot study

Background: Management strategy in ovarian cancer includes a combination of cytoreductive surgery and chemotherapy. Interval cytoreductive surgery has been shown to be oncologically non-inferior to primary cytoreduction with the additional benefit of reduced morbidity. Lymphadenectomy as a component of cytoreductive surgery has been controversial with an unproven therapeutic benefit.Methods: Records of patients with a histological diagnosis of ovarian cancer and treated with interval cytoreduction were evaluated. Disease related, pathological and treatment data collected for analysis.Results: The study included 32 patients with a mean age of 56 years (41-76). Serous papillary tumors (42%) were the predominate histology and the majority were in stage III disease (84%). Optimal cytoreduction was achieved in 93%. The mean nodal harvest was 9.8 nodes with left pelvic dissection yielding slightly more nodes than the right (4.5 vs 5.2). Nodal positivity was observed in just one patient (3%). A total of 314 were nodes examined with only 2 (0.6%) yielding persistent disease. The nodal positivity yield tested as a categorical variable by the binomial test returned P=0.0001.Conclusions: It is possible to omit pelvic nodal dissection during interval cytoreduction in otherwise optimally cytoreduced patients particularly when imaging and intraoperative assessment are not suggestive of pelvic nodal metastasis

Sub-Riemannian Geometry and Time Optimal Control of Three Spin Systems: Quantum Gates and Coherence Transfer

Many coherence transfer experiments in Nuclear Magnetic Resonance Spectroscopy, involving network of coupled spins, use temporary spin-decoupling to produce desired effective Hamiltonians. In this paper, we show that significant time can be saved in producing an effective Hamiltonian, if spin-decoupling is avoided. We provide time optimal pulse sequences for producing an important class of effective Hamiltonians in three spin networks. These effective Hamiltonians are useful for coherence transfer experiments and implementation of quantum logic gates in NMR quantum computing. It is demonstrated that computing these time optimal pulse sequences can be reduced to geometric problems that involve computing sub-Riemannian geodesics on Homogeneous spaces

One-neutron knockout from 57^{57}Ni

The single-particle structure of $^{57}$Ni and level structure of $^{56}$Ni were investigated with the \mbox{$^{9}$Be ($^{57}$Ni,$^{56}$Ni+$\gamma$)$\it{X}$} reaction at 73 MeV/nucleon. An inclusive cross section of 41.4(12) mb was obtained for the reaction, compared to a theoretical prediction of 85.4 mb, hence only 48(2)% of the theoretical cross section is exhausted. This reduction in the observed spectroscopic strength is consistent with that found for lighter well-bound nuclei. One-neutron removal spectroscopic factors of 0.58(11) to the ground state and 3.7(2) to all excited states of $^{56}$Ni were deduced.Comment: Phys. Rev. C, accepte

Optimal Control of Quantum Dissipative Dynamics: Analytic solution for cooling the three level Λ\Lambda system

We study the problem of optimal control of dissipative quantum dynamics. Although under most circumstances dissipation leads to an increase in entropy (or a decrease in purity) of the system, there is an important class of problems for which dissipation with external control can decrease the entropy (or increase the purity) of the system. An important example is laser cooling. In such systems, there is an interplay of the Hamiltonian part of the dynamics, which is controllable and the dissipative part of the dynamics, which is uncontrollable. The strategy is to control the Hamiltonian portion of the evolution in such a way that the dissipation causes the purity of the system to increase rather than decrease. The goal of this paper is to find the strategy that leads to maximal purity at the final time. Under the assumption that Hamiltonian control is complete and arbitrarily fast, we provide a general framework by which to calculate optimal cooling strategies. These assumptions lead to a great simplification, in which the control problem can be reformulated in terms of the spectrum of eigenvalues of $\rho$, rather than $\rho$ itself. By combining this formulation with the Hamilton-Jacobi-Bellman theorem we are able to obtain an equation for the globaly optimal cooling strategy in terms of the spectrum of the density matrix. For the three-level $\Lambda$ system, we provide a complete analytic solution for the optimal cooling strategy. For this system it is found that the optimal strategy does not exploit system coherences and is a 'greedy' strategy, in which the purity is increased maximally at each instant.Comment: 9 pages, 3 fig

Astrophysical S_{17}(0) factor from a measurement of d(7Be,8B)n reaction at E_{c.m.} = 4.5 MeV

Angular distribution measurements of $^2$H($^7$Be,$^7$Be)$^2$H and $^2$H($^7$Be,$^8$B)$n$ reactions at $E_{c.m.}\sim$~4.5 MeV were performed to extract the astrophysical $S_{17}(0)$ factor using the asymptotic normalization coefficient (ANC) method. For this purpose a pure, low emittance $^7$Be beam was separated from the primary $^7$Li beam by a recoil mass spectrometer operated in a novel mode. A beam stopper at 0$^{\circ}$ allowed the use of a higher $^7$Be beam intensity. Measurement of the elastic scattering in the entrance channel using kinematic coincidence, facilitated the determination of the optical model parameters needed for the analysis of the transfer data. The present measurement significantly reduces errors in the extracted $^7$Be(p,$\gamma$) cross section using the ANC method. We get $S_{17}$~(0)~=~20.7~$\pm$~2.4 eV~b.Comment: 15 pages including 3 eps figures, one figure removed and discussions updated. Version to appear in Physical Review