Algorithms for the minimum non-separating path and the balanced connected bipartition problems on grid graphs (With erratum)

For given a pair of nodes in a graph, the minimum non-separating path problem looks for a minimum weight path between the two nodes such that the remaining graph after removing the path is still connected. The balanced connected bipartition (BCP$_2$) problem looks for a way to bipartition a graph into two connected subgraphs with their weights as equal as possible. In this paper we present an algorithm in time $O(N\log N)$ for finding a minimum weight non-separating path between two given nodes in a grid graph of $N$ nodes with positive weight. This result leads to a 5/4-approximation algorithm for the BCP$_2$ problem on grid graphs, which is the currently best ratio achieved in polynomial time. We also developed an exact algorithm for the BCP$_2$ problem on grid graphs. Based on the exact algorithm and a rounding technique, we show an approximation scheme, which is a fully polynomial time approximation scheme for fixed number of rows.Comment: With erratu

Gain in cellular organization of inflammatory breast cancer: A 3D in vitro model that mimics the in vivo metastasis

<p>Abstract</p> <p>Background</p> <p>The initial step of metastasis in carcinomas, often referred to as the epithelial-mesenchymal transition (EMT), occurs via the loss of adherens junctions (e.g. cadherins) by the tumor embolus. This leads to a subsequent loss of cell polarity and cellular differentiation and organization, enabling cells of the embolus to become motile and invasive. However highly malignant inflammatory breast cancer (IBC) over-expresses E-cadherin. The human xenograft model of IBC (MARY-X), like IBC, displays the signature phenotype of an exaggerated degree of lymphovascular invasion (LVI) <it>in situ </it>by tumor emboli. An intact E-cadherin/α, β-catenin axis mediates the tight, compact clump of cells found both <it>in vitro </it>and <it>in vivo </it>as spheroids and tumor emboli, respectively.</p> <p>Methods</p> <p>Using electron microscopy and focused ion beam milling to acquire <it>in situ </it>sections, we performed ultrastructural analysis of both an IBC and non-IBC, E-cadherin positive cell line to determine if retention of this adhesion molecule contributed to cellular organization.</p> <p>Results</p> <p>Here we report through ultrastructural analysis that IBC exhibits a high degree of cellular organization with polar elements such as apical/lateral positioning of E-cadherin, apical surface microvilli, and tortuous lumen-like (canalis) structures. In contrast, agarose-induced spheroids of MCF-7, a weakly invasive E-cadherin positive breast carcinoma cell line, do not exhibit ultrastructural polar features.</p> <p>Conclusions</p> <p>This study has determined that the highly metastatic IBC with an exaggerated malignant phenotype challenges conventional wisdom in that instead of displaying a loss of cellular organization, IBC acquires a highly structured architecture.</p> <p>These findings suggest that the metastatic efficiency might be linked to the formation and maintenance of these architectural features. The comparative architectural features of both the spheroid and embolus of MARY-X provide an <it>in vitro </it>model with tractable <it>in vivo </it>applications.</p

Flavor in Minimal Conformal Technicolor

We construct a complete, realistic, and natural UV completion of minimal conformal technicolor that explains the origin of quark and lepton masses and mixing angles. As in "bosonic technicolor", we embed conformal technicolor in a supersymmetric theory, with supersymmetry broken at a high scale. The exchange of heavy scalar doublets generates higher-dimension interactions between technifermions and quarks and leptons that give rise to quark and lepton masses at the TeV scale. Obtaining a sufficiently large top quark mass requires strong dynamics at the supersymmetry breaking scale in both the top and technicolor sectors. This is natural if the theory above the supersymmetry breaking also has strong conformal dynamics. We present two models in which the strong top dynamics is realized in different ways. In both models, constraints from flavor-changing effects can be easily satisfied. The effective theory below the supersymmetry breaking scale is minimal conformal technicolor with an additional light technicolor gaugino. We argue that this light gaugino is a general consequence of conformal technicolor embedded into a supersymmetric theory. If the gaugino has mass below the TeV scale it will give rise to an additional pseudo Nambu-Goldstone boson that is observable at the LHC.Comment: 37 pages; references adde

Decomposition techniques with mixed integer programming and heuristics for home healthcare planning

We tackle home healthcare planning scenarios in the UK using decomposition methods that incorporate mixed integer programming solvers and heuristics. Home healthcare planning is a difficult problem that integrates aspects from scheduling and routing. Solving real-world size instances of these problems still presents a significant challenge to modern exact optimization solvers. Nevertheless, we propose decomposition techniques to harness the power of such solvers while still offering a practical approach to produce high-quality solutions to real-world problem instances. We first decompose the problem into several smaller sub-problems. Next, mixed integer programming and/or heuristics are used to tackle the sub-problems. Finally, the sub-problem solutions are combined into a single valid solution for the whole problem. The different decomposition methods differ in the way in which subproblems are generated and the way in which conflicting assignments are tackled (i.e. avoided or repaired). We present the results obtained by the proposed decomposition methods and compare them to solutions obtained with other methods. In addition, we conduct a study that reveals how the different steps in the proposed method contribute to those results. The main contribution of this paper is a better understanding of effective ways to combine mixed integer programming within effective decomposition methods to solve real-world instances of home healthcare planning problems in practical computation time

Measurement of the Relative Branching Fraction of Υ(4S)\Upsilon(4S) to Charged and Neutral B-Meson Pairs

We analyze 9.7 x 10^6 B\bar{B}$ pairs recorded with the CLEO detector to determine the production ratio of charged to neutral B-meson pairs produced at the Y(4S) resonance. We measure the rates for B^0 -> J/psi K^{(*)0} and B^+ -> J/psi K^{(*)+} decays and use the world-average B-meson lifetime ratio to extract the relative widths f+-/f00 = Gamma(Y(4S) -> B+B-)/Gamma(Y(4S) -> B0\bar{B0}) = = 1.04 +/- 0.07(stat) +/- 0.04(syst). With the assumption that f+- + f00 = 1, we obtain f00 = 0.49 +/- 0.02(stat) +/- 0.01(syst) and f+- = 0.51 +/- 0.02(stat) +/- 0.01(syst). This production ratio and its uncertainty apply to all exclusive B-meson branching fractions measured at the Y(4S) resonance.Comment: 11 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

First Observation of the Decays B0→D∗−ppˉπ+B^{0}\to D^{*-}p\bar{p}\pi^{+} and B^{0}\to D^{*-}p\bar{n}$

We report the first observation of exclusive decays of the type B to D^* N anti-N X, where N is a nucleon. Using a sample of 9.7 times 10^{6} B-Bbar pairs collected with the CLEO detector operating at the Cornell Electron Storage Ring, we measure the branching fractions B(B^0 \to D^{*-} proton antiproton \pi^+) = ({6.5}^{+1.3}_{-1.2} +- 1.0) \times 10^{-4} and B(B^0 \to D^{*-} proton antineutron) = ({14.5}^{+3.4}_{-3.0} +- 2.7) times 10^{-4}. Antineutrons are identified by their annihilation in the CsI electromagnetic calorimeter.Comment: 9 pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

Study of the Decays B0 --> D(*)+D(*)-

The decays B0 --> D*+D*-, B0 --> D*+D- and B0 --> D+D- are studied in 9.7 million Y(4S) --> BBbar decays accumulated with the CLEO detector. We determine Br(B0 --> D*+D*-) = (9.9+4.2-3.3+-1.2)e-4 and limit Br(B0 --> D*+D-) < 6.3e-4 and Br(B0 --> D+D-) < 9.4e-4 at 90% confidence level (CL). We also perform the first angular analysis of the B0 --> D*+D*- decay and determine that the CP-even fraction of the final state is greater than 0.11 at 90% CL. Future measurements of the time dependence of these decays may be useful for the investigation of CP violation in neutral B meson decays.Comment: 21 pages, 5 figures, submitted to Phys. Rev.

A Search for B→τνB\to \tau\nu

We report results of a search for $B\to\tau\nu$ in a sample of 9.7 million charged $B$ meson decays. The search uses both $\pi\nu$ and $\ell\nu\bar\nu$ decay modes of the $\tau$, and demands exclusive reconstruction of the companion $\bar B$ decay to suppress background. We set an upper limit on the branching fraction ${\cal B}(B\to \tau\nu) < 8.4\times 10^{-4}$ at 90% confidence level. With slight modification to the analysis we also establish ${\cal B}(B^\pm\to K^\pm\nu\bar\nu) < 2.4\times 10^{-4}$ at 90% confidence level.Comment: 10 ages postscript, also available through http://w4.lns.cornell.edu/public/CLN

Measurements of B --> D_s^{(*)+} D^{*(*)} Branching Fractions

This article describes improved measurements by CLEO of the $B^0 \to D_s^+ D^{*-}$ and $B^0 \to D_s^{*+} D^{*-}$ branching fractions, and first evidence for the decay $B^+ \to D_s^{(*)+} \bar{D}^{**0}$, where $\bar{D}^{**0}$ represents the sum of the $\bar{D}_1(2420)^0$, $\bar{D}_2^*(2460)^0$, and $\bar{D}_1(j=1/2)^0$ L=1 charm meson states. Also reported is the first measurement of the $D_s^{*+}$ polarization in the decay $B^0 \to D_s^{*+} D^{*-}$. A partial reconstruction technique, employing only the fully reconstructed $D_s^+$ and slow pion $\pi_s^-$ from the $D^{*-} \to \bar{D}^0 \pi^-_s$ decay, enhances sensitivity. The observed branching fractions are ${\mathcal B} (B^0 \to D_s^+ D^{*-}) = (1.10 \pm 0.18 \pm 0.10 \pm 0.28)$, ${\mathcal B} (B^0 \to D_s^{*+} D^{*-}) = (1.82 \pm 0.37 \pm 0.24 \pm 0.46)$, and ${\mathcal B} (B^+ \to D_s^{(*)+} \bar{D}^{**0}) = (2.73 \pm 0.78 \pm 0.48 \pm 0.68)$, where the first error is statistical, the second systematic, and the third is due to the uncertainty in the $D_s^+ \to \phi \pi^+$ branching fraction. The measured $D_s^{*+}$ longitudinal polarization, $\Gamma_L/\Gamma = (50.6 \pm 13.9 \pm 3.6)$, is consistent with the factorization prediction of 54%.Comment: 26 pages (LaTeX), 15 figures. To be submitted to PR

Improved Measurement of the Pseudoscalar Decay Constant fDsf_{D_{s}}

We present a new determination of the Ds decay constant, f_{Ds} using 5 million continuum charm events obtained with the CLEO II detector. Our value is derived from our new measured ratio of widths for Ds -> mu nu/Ds -> phi pi of 0.173+/- 0.021 +/- 0.031. Taking the branching ratio for Ds -> phi pi as (3.6 +/- 0.9)% from the PDG, we extract f_{Ds} = (280 +/- 17 +/- 25 +/- 34){MeV}. We compare this result with various model calculations.Comment: 23 page postscript file, postscript file also available through http://w4.lns.cornell.edu/public/CLN