911 research outputs found

    Integer programming based solution approaches for the train dispatching problem

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    Railroads face the challenge of competing with the trucking industry in a fastpaced environment. In this respect, they are working toward running freight trains on schedule and reducing travel times. The planned train schedules consist of departure and arrival times at main stations on the rail network. A detailed timetable, on the other hand, consists of the departure and arrival times of each train in each track section of its route. The train dispatching problem aims to determine detailed timetables over a rail network in order to minimize deviations from the planned schedule. We provide a new integer programming formulation for this problem based on a spacetime network; we propose heuristic algorithms to solve it and present computational results of these algorithms. Our approach includes some realistic constraints that have not been previously considered as well as all the assumptions and practical issues considered by the earlier works

    Plasmon Injection to Compensate and Control Losses in Negative Index Metamaterials

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    Metamaterials have introduced a whole new world of unusual materials with functionalities that cannot be attained in naturally occurring material systems by mimicking and controlling the natural phenomena at subwavelength scales. However, the inherent absorption losses pose fundamental challenge to the most fascinating applications of metamaterials. Based on a novel plasmon injection (PI or \Pi) scheme, we propose a coherent optical amplification technique to compensate losses in metamaterials. Although the proof of concept device here operates under normal incidence only, our proposed scheme can be generalized to arbitrary form of incident waves. The \Pi-scheme is fundamentally different than major optical amplification schemes. It does not require gain medium, interaction with phonons, or any nonlinear medium. The \Pi-scheme allows for loss-free metamaterials. It is ideally suited for mitigating losses in metamaterials operating in the visible spectrum and is scalable to other optical frequencies. These findings open the possibility of reviving the early dreams of making 'magical' metamaterials from scratch.Comment: Main text, 8 pages with 4 figures; supplemental material, 21 pages with 21 figure

    Unparticle Physics in the Moller Scattering

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    We investigate the virtual effects of vector unparticles in the Moller scattering. We derive the analytic expression for scattering amplitudes with unpolarized beams. We obtain 95% confidence level limits on the unparticle couplings λV\lambda_{V} and λA\lambda_{A} with integrated luminosity of Lint=50,500fb−1L_{int}=50, 500 fb^{-1} and s=100,300\sqrt{s}=100, 300 and 500 GeV energies. We show that limits on λV\lambda_{V} are more sensitive than λA\lambda_{A}.Comment: 10 pages, 5 figures, 4 table

    Kraus representation of damped harmonic oscillator and its application

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    By definition, the Kraus representation of a harmonic oscillator suffering from the environment effect, modeled as the amplitude damping or the phase damping, is directly given by a simple operator algebra solution. As examples and applications, we first give a Kraus representation of a single qubit whose computational basis states are defined as bosonic vacuum and single particle number states. We further discuss the environment effect on qubits whose computational basis states are defined as the bosonic odd and even coherent states. The environment effects on entangled qubits defined by two different kinds of computational basis are compared with the use of fidelity.Comment: 9 pages, 3 figure

    Strong coupling constants of bottom and charmed mesons with scalar, pseudoscalar and axial vector kaons

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    The strong coupling constants, gDsDK0∗g_{D_{s}DK_0^*}, gBsBK0∗g_{B_{s}BK_0^*}, gDs∗DKg_{D^{\ast}_{s}D K}, gBs∗BKg_{B^{\ast}_{s}BK}, gDs∗DK1g_{D^{\ast}_{s}D K_1} and gBs∗BK1g_{B^{\ast}_{s}BK_1}, where K0∗K_0^*, KK and K1K_1 are scalar, pseudoscalar and axial vector kaon mesons, respectively are calculated in the framework of three-point QCD sum rules. In particular, the correlation functions of the considered vertices when both B(D)B(D) and K0∗(K)(K1)K_0^*(K)(K_1) mesons are off-shell are evaluated. In the case of K1K_1, which is either K1(1270)K_1(1270) or K1(1400)K_1(1400), the mixing between these two states are also taken into account. A comparison of the obtained result with the existing prediction on gDs∗DKg_{D^{\ast}_{s}D K} as the only coupling constant among the considered vertices, previously calculated in the literature, is also made.Comment: 20 Pages, 3 Figures and 8 Table

    ZZγZZ\gamma and ZγγZ\gamma\gamma couplings in γe\gamma e collision with polarized beams

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    The potential of γ\gammae mode of linear e+e−e^{+}e^{-} collider to probe ZZγZZ\gamma and ZγγZ\gamma\gamma vertices is investigated through the Z boson production from the procees γe→Ze\gamma e\to Z e. Considering the longitudinal and transverse polarization states of the Z boson and incoming polarized beams we find the 95% C.L. limits on the form factors h3Zh_{3}^{Z}, h4Zh_{4}^{Z}, h3γh_{3}^{\gamma} and h4γh_{4}^{\gamma} with integrated luminosity 500fb−1fb^{-1} and s=\sqrt{s}=0.5, 1, 1.5 TeV energies. It is shown that the polarization can improve sensitivities by factors 2-3 depending on the energy.Comment: 12 pages, 8 EPS figure

    A simple way to reduce heat stress in laying hens as judged by egg laying, body weight gain and biochemical parameters

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    This study was designed to test the effects of feed withdrawal and darkening on the performance, triiodothyronine (T3), thyroxine (T4), thyroid-stimulating hormone (TSH), adrenocorticotropic hormone (ACTH), and some blood serum metabolite and mineral concentrations of laying hens reared at high ambient temperatures ranging from 25 to 35 °C. Ninety, 16-week-old hens (Ross Brown) were divided into 3 groups, 30 hens each. The first group was used as control. Hens in the second group (feed withdrawal) were subjected to feed removal from 14:00 to 18:00, and hens in the third group (darkening) were subjected to light restriction from 14:00 to 18:00 using black curtains. Liveweight, feed intake, and egg production were higher (P < 0.01) in the feed withdrawal and darkening groups, particularly in the darkening group, than in the control. Water intake was higher in the control group compared with the feed withdrawal and darkening groups (P < 0.01). T3, T4, and TSH concentrations in the serum were higher (P < 0.01), whereas ACTH serum concentration was lower (P < 0.01) in the feed withdrawal and darkening groups compared with the control. The haematocrit was higher in the feed withdrawal and darkening groups compared with the control (P < 0.01). Darkening and feed withdrawal treatments increased serum glucose, urea-N, uric acid, albumin, triglyceride, cholesterol, Ca, P, Na, and K concentrations, also the activities of amylase and alkaline phosphatase, but did not influence the activities of serum glutamic-oxaloacetic transaminase (SGOT) and serum glutamic pyruvic transaminase (SGPT). The present study found that feed withdrawal and darkening, particularly darkening, at high temperatures during the summer months offer a good management practice to reduce heat stress related depression in feed intake and egg production in laying hens

    Geometry of the Field-Moment Spaces for Quadratic Bosonic Systems: Diabolically Degenerated Exceptional Points on Complex kk-Polytopes

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    kk-Polytopes are a generalization of polyhedra in kk dimensions. Here, we show that complex kk-polytopes naturally emerge in the higher-order field moments spaces of quadratic bosonic systems, thus revealing their geometric character. In particular, a complex-valued evolution matrix, governing the dynamics of kkth-order field moments of a bosonic dimer, can describe a complex kk-dimensional hypercube. The existence of such kk-polytopes is accompanied by the presence of high-order diabolic points (DPs). Interestingly, when the field-moment space additionally exhibits exceptional points (EPs), the formation of kk-polytopes may lead to the emergence of diabolically degenerated EPs, due to the interplay between DPs and EPs. Such intriguing spectral properties of complex polytopes may enable constructing photonic lattice systems with similar spectral features in real space. Our results can be exploited in various quantum protocols based on EPs, paving a new direction of research in this field.Comment: 9 page

    An assessment of nasal and orbital parameters in human fetuses

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    Background: Nasal bone aplasia and hypoplasia have been reported on fetuses with aneuploidy. Trisomy 21 is one of the most common chromosomal abnormality detected in new-borns. The purpose of our study is to obtain data of some face parameters in Turkish fetal population and to contribute creation of reference ranges that may be used for prenatal diagnosis.Methods: This study was performed in 66 spontaneously aborted fetuses (47 second trimester and 19 third trimester) (28 male and 38 female) with no detectable external pathology or anomalies. Measurements were designed as nasal bone length (NBL), nose length (NL), nose width (NW), nostril width (NsW),                intraocular distance (IOD), innercanthal distance (ICD), outercanthal distance (OCD), orbital diameter (OD), biparietal diameter (BPD).Results: In comparison between genders, ICD and BPD averages were found significantly higher in male fetuses than female fetuses (P<0.05). There was not any statistically significant difference between averages of the values on the right and left. The difference between second and the third trimester was significant in terms of all parameters (P<0.05). A strong correlation was detected between gestational age and our parameters.Conclusions: Present study has contributed to create reference ranges of Turkish community. When importance of early diagnosis is considered, we believe that this data will be useful for clinicians
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