1,635 research outputs found

    Dephasing due to Intermode Coupling in Superconducting Stripline Resonators

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    The nonlinearity exhibited by the kinetic inductance of a superconducting stripline couples stripline resonator modes together in a manner suitable for quantum non-demolition measurement of the number of photons in a given resonator mode. Quantum non-demolition measurement is accomplished by coherently driving another resonator mode, referred to as the detector mode, and measuring its response. We show that the sensitivity of such a detection scheme is directly related to the dephasing rate induced by such an intermode coupling. We show that high sensitivity is expected when the detector mode is driven into the nonlinear regime and operated close to a point where critical slowing down occurs

    Meta-analysis of the efficacy of a single stage laparoscopic management versus two-stage endoscopic management of symptomatic gallstones with common bile duct stones.

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    Background. The optimal treatment of gallstones with associated common bile duct stones in the laparoscopic era is controversial. Various reviews and decision based algorithms have been published, but the superior treatment modality is unclear. Therefore, a metaanalysis was conducted to compare the two most commonly used treatment strategies. Methods. A systematic review was conducted to compare single stage laparoscopic cholecystectomy with common bile duct exploration versus a combined endoscopic and laparoscopic treatment. Eligible studies were identified using a search of Medline, Embase, Cochrane and Science Citation Index Expanded databases. Appropriately selected articles were independently reviewed and data was extracted and cross referenced. A meta-analysis was conducted of the pooled trial data to determine difference in outcomes. Results. A total of seven randomized trials were identified with 746 patients with 366 in the laparoscopic only treatment group and 380 in the combined endoscopic and laparoscopic treatment arms. There was no significant difference in successful bile duct clearance between the two groups (OR 1.23; 95% CI 0.55 to 2.75, P = 0.61). There was no statistical difference in morbidity (RR 1.23; 95% CI 0.92 to 1.66; P = 0.17), mortality (RD -0.00; 95% CI -0.02 to 0.01, P = 0.59) or length of hospital stay (MD -0.31; 95% CI -1.68 to 1.06, P = 0.66). However, there was a statistically significant difference in the duration of procedure in favour of the single stage laparoscopic treatment (MD -6.83; 95% CI -9.59 to -4.07, P \u3c 0.00001). Conclusion. Both the laparoscopic alone or the combined endoscopic and laparoscopic treatment approaches show comparative efficacy in management of symptomatic gallstones with associated choledocholithiasis

    On computational irreducibility and the predictability of complex physical systems

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    Using elementary cellular automata (CA) as an example, we show how to coarse-grain CA in all classes of Wolfram's classification. We find that computationally irreducible (CIR) physical processes can be predictable and even computationally reducible at a coarse-grained level of description. The resulting coarse-grained CA which we construct emulate the large-scale behavior of the original systems without accounting for small-scale details. At least one of the CA that can be coarse-grained is irreducible and known to be a universal Turing machine.Comment: 4 pages, 2 figures, to be published in PR

    Pengendalian Biaya Dan Waktu Dengan Metode Analisis Nilai Dan Hasil Dengan Microsoft Project 2010 (Studi Kasus : Gedung Mantos Tahap III)

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    Pengendalian dalam proyek merupakan fungsi paling pokok dama pelaksanaan suatu proyek konstruksi. Pengendalian sebagai alat untuk membantu mengendalikan proyek, membantu pelaksanaan dan penyelesaian dalam suatu proyek konstruksi. Pelaksanaan suatu proyek umumnya sering terjadi penyimpanan – penyimpangan dimana biaya yang dikeluarkan dan jadwal yang direncanakan melampaui batas yang direncanakan. Pengendalian proyek bertujuan untuk mengendaliakn biaya dan waktu agar sesuai dengan biaya dan jadwal yang direncanakan. Metode nilai hasil merupakan pengembangan teknik pengendalian grafik S sampai mampu menganalisis varians biaya secara stimulant sehingga dapat melihat kemajuan proyek dari jadwal dengan anggaran yang telah dialokasikan. Metode nilai hasil ini mencakup rencana anggaran dan biaya (RAB), daftar harga satuan upah dan bahan, analisa harga satuan serta laporan kemajuan proyek di olah untuk mendapatkan BCWS (Budgeted Cost of Work Schedule), ACWP (Actual Cost of Work Performance) dan BCWP (Budgeted Cost of Work Performance) Dari hasil penerapan metode konsep nilai hasil diketahui sampai hasil tinjauan pada minggu ke 6 di dapatkan BCWS = Rp. 46,932,747,947.29; ACWP = Rp. 45,928,815,000.00; BCWP = Rp. 47,633,716,500.77; sedangkan varian biaya (CV) pada bulan satu sampai tiga adalah negative (-) dan pada bulan ke empat sampai akhir pelaksanaan proyek adalah positif (+) begitu pun varian jadwal. Dan dapat diketahui prakiraan biaya akhir proyek EAC (Estimate At Complection) adalah Rp. 70,829,440,000.00, dengan anggaran rencana sebesar Rp. 72,391,666,414.54. Estimate Complection Date (ECD) proyek mengalami sedikit kemajuan terhadap jadwal yang direncanakan yaitu 2 har

    Coarse-graining of cellular automata, emergence, and the predictability of complex systems

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    We study the predictability of emergent phenomena in complex systems. Using nearest neighbor, one-dimensional Cellular Automata (CA) as an example, we show how to construct local coarse-grained descriptions of CA in all classes of Wolfram's classification. The resulting coarse-grained CA that we construct are capable of emulating the large-scale behavior of the original systems without accounting for small-scale details. Several CA that can be coarse-grained by this construction are known to be universal Turing machines; they can emulate any CA or other computing devices and are therefore undecidable. We thus show that because in practice one only seeks coarse-grained information, complex physical systems can be predictable and even decidable at some level of description. The renormalization group flows that we construct induce a hierarchy of CA rules. This hierarchy agrees well with apparent rule complexity and is therefore a good candidate for a complexity measure and a classification method. Finally we argue that the large scale dynamics of CA can be very simple, at least when measured by the Kolmogorov complexity of the large scale update rule, and moreover exhibits a novel scaling law. We show that because of this large-scale simplicity, the probability of finding a coarse-grained description of CA approaches unity as one goes to increasingly coarser scales. We interpret this large scale simplicity as a pattern formation mechanism in which large scale patterns are forced upon the system by the simplicity of the rules that govern the large scale dynamics.Comment: 18 pages, 9 figure

    The Clumping Transition in Niche Competition: a Robust Critical Phenomenon

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    We show analytically and numerically that the appearance of lumps and gaps in the distribution of n competing species along a niche axis is a robust phenomenon whenever the finiteness of the niche space is taken into account. In this case depending if the niche width of the species σ\sigma is above or below a threshold σc\sigma_c, which for large n coincides with 2/n, there are two different regimes. For σ>sigmac\sigma > sigma_c the lumpy pattern emerges directly from the dominant eigenvector of the competition matrix because its corresponding eigenvalue becomes negative. For σ</sigmac\sigma </- sigma_c the lumpy pattern disappears. Furthermore, this clumping transition exhibits critical slowing down as σ\sigma is approached from above. We also find that the number of lumps of species vs. σ\sigma displays a stair-step structure. The positions of these steps are distributed according to a power-law. It is thus straightforward to predict the number of groups that can be packed along a niche axis and it coincides with field measurements for a wide range of the model parameters.Comment: 16 pages, 7 figures; http://iopscience.iop.org/1742-5468/2010/05/P0500

    Influence of Strouhal number on pulsating methane–air coflow jet diffusion flames

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    Four periodically time-varying methane–air laminar coflow jet diffusion flames, each forced by pulsating the fuel jet's exit velocity Uj sinusoidally with a different modulation frequency wj and with a 50% amplitude variation, have been computed. Combustion of methane has been modeled by using a chemical mechanism with 15 species and 42 reactions, and the solution of the unsteady Navier–Stokes equations has been obtained numerically by using a modified vorticity-velocity formulation in the limit of low Mach number. The effect of wj on temperature and chemistry has been studied in detail. Three different regimes are found depending on the flame's Strouhal number S=awj/Uj, with a denoting the fuel jet radius. For small Strouhal number (S=0.1), the modulation introduces a perturbation that travels very far downstream, and certain variables oscillate at the frequency imposed by the fuel jet modulation. As the Strouhal number grows, the nondimensional frequency approaches the natural frequency of oscillation of the flickering flame (S≃0.2). A coupling with the pulsation frequency enhances the effect of the imposed modulation and a vigorous pinch-off is observed for S=0.25 and S=0.5. Larger values of S confine the oscillation to the jet's near-exit region, and the effects of the pulsation are reduced to small wiggles in the temperature and concentration values. Temperature and species mass fractions change appreciably near the jet centerline, where variations of over 2% for the temperature and 15% and 40% for the CO and OH mass fractions, respectively, are found. Transverse to the jet movement, however, the variations almost disappear at radial distances on the order of the fuel jet radius, indicating a fast damping of the oscillation in the spanwise direction

    Concurrent MEK targeted therapy prevents MAPK pathway reactivation during BRAFV600E targeted inhibition in a novel syngeneic murine glioma model.

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    Inhibitors of BRAFV600E kinase are currently under investigations in preclinical and clinical studies involving BRAFV600E glioma. Studies demonstrated clinical response to such individualized therapy in the majority of patients whereas in some patients tumors continue to grow despite treatment. To study resistance mechanisms, which include feedback activation of mitogen-activated protein kinase (MAPK) signaling in melanoma, we developed a luciferase-modified cell line (2341luc) from a BrafV600E mutant and Cdkn2a- deficient murine high-grade glioma, and analyzed its molecular responses to BRAFV600E- and MAPK kinase (MEK)-targeted inhibition. Immunocompetent, syngeneic FVB/N mice with intracranial grafts of 2341luc were tested for effects of BRAFV600E and MEK inhibitor treatments, with bioluminescence imaging up to 14-days after start of treatment and survival analysis as primary indicators of inhibitor activity. Intracranial injected tumor cells consistently generated high-grade glioma-like tumors in syngeneic mice. Intraperitoneal daily delivery of BRAFV600E inhibitor dabrafenib only transiently suppressed MAPK signaling, and rather increased Akt signaling and failed to extend survival for mice with intracranial 2341luc tumor. MEK inhibitor trametinib delivered by oral gavage daily suppressed MAPK pathway more effectively and had a more durable anti-growth effect than dabrafenib as well as a significant survival benefit. Compared with either agent alone, combined BRAFV600E and MEK inhibitor treatment was more effective in reducing tumor growth and extending animal subject survival, as corresponding to sustained MAPK pathway inhibition. Results derived from the 2341luc engraftment model application have clinical implications for the management of BRAFV600E glioma

    Magnetocaloric effect in Mn-containing Hitperm-type alloys.

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    The magnetocaloric effect of Fe60−xMnxCo18Nb6B16 x=0,2,4 is studied. Mn addition decreases the Curie temperature of the alloys but also reduces the peak entropy change and the refrigerant capacity of the material. The estimated adiabatic temperature change, for a maximum applied field of 15 kOe, is 1.3 K. Obtained values are comparable to those of some Nanoperm-type alloys. The magnetic entropy change, SM, of the studied samples follows a master curve, which is the same for all of them. The exponent controlling the field dependence of SM scales with reduced temperature in the same way as the master curve does
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