1,951 research outputs found

    Randomized Search of Graphs in Log Space and Probabilistic Computation

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    Reingold has shown that L = SL, that s-t connectivity in a poly-mixing digraph is complete for promise-RL, and that s-t connectivity for a poly-mixing out-regular digraph with known stationary distribution is in L. Several properties that bound the mixing times of random walks on digraphs have been identified, including the digraph conductance and the digraph spectral expansion. However, rapidly mixing digraphs can still have exponential cover time, thus it is important to specifically identify structural properties of digraphs that effect cover times. We examine the complexity of random walks on a basic parameterized family of unbalanced digraphs called Strong Chains (which model weakly symmetric logspace computations), and a special family of Strong Chains called Harps. We show that the worst case hitting times of Strong Chain families vary smoothly with the number of asymmetric vertices and identify the necessary condition for non-polynomial cover time. This analysis also yields bounds on the cover times of general digraphs. Next we relate random walks on graphs to the random walks that arise in Monte Carlo methods applied to optimization problems. We introduce the notion of the asymmetric states of Markov chains and use this definition to obtain some results about Markov chains. We also obtain some results on the mixing times for Markov Chain Monte Carlo Methods. Finally, we consider the question of whether a single long random walk or many short walks is a better strategy for exploration. These are walks which reset to the start after a fixed number of steps. We exhibit digraph families for which a few short walks are far superior to a single long walk. We introduce an iterative deepening random search. We use this strategy estimate the cover time for poly-mixing subgraphs. Finally we discuss complexity theoretic implications and future work

    Key Factors Affecting the Performance of RFID Tag Antennas

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    INTUITIVE DECISION THEORY ANALYSIS AND THE EVALUATION MODEL

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    Intuitive decision-making studies the decision-makerā€™s decision-making behavior from the perspective of image thinking, which it poses a challenge to the classic decision-making hypothesis pursuing ā€œoptimal decisionā€ because the outcomes of intuitive decision-making are difficulty to measure and its process isnā€™t easy to describe and control. Therefore it has not drawn the expertsā€™ attention. This paper tries to establish an evaluation model of the intuitive decision-making as to giving a direction and inspiration of the quantization of intuitive decision-making, based on the systematic analysis of the existing domestic and international theory of intuitive decision-making. Key words: Intuitive decision-making, Thinking in images, The evaluation mode

    Identifying Tmem59 related gene regulatory network of mouse neural stem cell from a compendium of expression profiles

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    <p>Abstract</p> <p>Background</p> <p>Neural stem cells offer potential treatment for neurodegenerative disorders, such like Alzheimer's disease (AD). While much progress has been made in understanding neural stem cell function, a precise description of the molecular mechanisms regulating neural stem cells is not yet established. This lack of knowledge is a major barrier holding back the discovery of therapeutic uses of neural stem cells. In this paper, the regulatory mechanism of mouse neural stem cell (NSC) differentiation by <it>tmem59 </it>is explored on the genome-level.</p> <p>Results</p> <p>We identified regulators of <it>tmem59 </it>during the differentiation of mouse NSCs from a compendium of expression profiles. Based on the microarray experiment, we developed the parallelized SWNI algorithm to reconstruct gene regulatory networks of mouse neural stem cells. From the inferred <it>tmem59 </it>related gene network including 36 genes, <it>pou6f1 </it>was identified to regulate <it>tmem59 </it>significantly and might play an important role in the differentiation of NSCs in mouse brain. There are four pathways shown in the gene network, indicating that <it>tmem59 </it>locates in the downstream of the signalling pathway. The real-time RT-PCR results shown that the over-expression of <it>pou6f1 </it>could significantly up-regulate <it>tmem59 </it>expression in C17.2 NSC line. 16 out of 36 predicted genes in our constructed network have been reported to be AD-related, including <it>Ace</it>, <it>aqp1</it>, <it>arrdc3</it>, <it>cd14</it>, <it>cd59a</it>, <it>cds1</it>, <it>cldn1</it>, <it>cox8b</it>, <it>defb11</it>, <it>folr1</it>, <it>gdi2</it>, <it>mmp3</it>, <it>mgp</it>, <it>myrip</it>, <it>Ripk4</it>, <it>rnd3</it>, and <it>sncg</it>. The localization of <it>tmem59 </it>related genes and functional-related gene groups based on the Gene Ontology (GO) annotation was also identified.</p> <p>Conclusions</p> <p>Our findings suggest that the expression of <it>tmem59 </it>is an important factor contributing to AD. The parallelized SWNI algorithm increased the efficiency of network reconstruction significantly. This study enables us to highlight novel genes that may be involved in NSC differentiation and provides a shortcut to identifying genes for AD.</p

    Magnon-induced non-Markovian friction of a domain wall in a ferromagnet

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    Motivated by the recent study on the quasiparticle-induced friction of solitons in superfluids, we theoretically study magnon-induced intrinsic friction of a domain wall in a one-dimensional ferromagnet. To this end, we start by obtaining the hitherto overlooked dissipative interaction of a domain wall and its quantum magnon bath to linear order in the domain-wall velocity and to quadratic order in magnon fields. An exact expression for the pertinent scattering matrix is obtained with the aid of supersymmetric quantum mechanics. We then derive the magnon-induced frictional force on a domain wall in two different frameworks: time-dependent perturbation theory in quantum mechanics and the Keldysh formalism, which yield identical results. The latter, in particular, allows us to verify the fluctuation-dissipation theorem explicitly by providing both the frictional force and the correlator of the associated stochastic Langevin force. The potential for magnons induced by a domain wall is reflectionless, and thus the resultant frictional force is non-Markovian similarly to the case of solitons in superfluids. They share an intriguing connection to the Abraham-Lorentz force that is well-known for its causality paradox. The dynamical responses of a domain wall are studied under a few simple circumstances, where the non-Markovian nature of the frictional force can be probed experimentally. Our work, in conjunction with the previous study on solitons in superfluids, shows that the macroscopic frictional force on solitons can serve as an effective probe of the microscopic degrees of freedom of the system.Comment: 13 pages, 2 figure

    Superconductivity induced by doping Platinum in BaFe2As2

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    By substituting Fe with the 5d-transition metal Pt in BaFe2As2, we have successfully synthesized the superconductors BaFe2-xPtxAs2. The systematic evolution of the lattice constants indicates that the Fe ions were successfully replaced by Pt ions. By increasing the doping content of Pt, the antiferromagnetic order and structural transition of the parent phase is suppressed and superconductivity emerges at a doping level of about x = 0.02. At a doping level of x = 0.1, we get a maximum transition temperature Tc of about 25 K. The synchrotron powder x-ray diffraction shows that the resistivity anomaly is in good agreement with the structural transition. The superconducting transitions at different magnetic fields were also measured at the doping level of about x = 0.1, yielding a slope of -dHc2/dT = 5.4 T/K near Tc. A phase diagram was established for the Pt doped 122 system. Our results suggest that superconductivity can also be easily induced in the FeAs family by substituting the Fe with Pt, with almost the similar maximum transition temperatures as doping Ni, Co, Rh and Ir.Comment: 6 pages, 5 figure

    Infectious Alopecia in a Dog Breeder After Renal Transplantation

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    Tinea capitis rarely occurs in renal transplant recipients. We report this living-related renal transplant patient receiving cyclosporine-based therapy who initially presented with severe exfoliation of the scalp with yellowish-white scales and marked hair loss. The lesions extended to the frontal area and both cheeks, resulting in several skin ulcers with perifocal erythematous inflammatory changes, and palpable cervical lymph nodes. A biopsy of a skin lesion revealed fungal infection and culture yielded Microsporum canis. The patient mentioned an outbreak of ringworm in her breeding dogs during this period. After adequate treatment of the patient and her infected animals with griseofulvin and disinfection of the environment, her skin lesions resolved dramatically, with regrowth of hair

    Nu Shu GPS: 25Ā°21ā€™00.5N, 111Ā°27ā€™17.7Eā€”An Interdisciplinary Cooperation between Dance, Calligraphy, and the Body in Multimedia Performance

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    'Nu Shu GPS: 25 Ā°21ā€™00.5N, 111Ā°27ā€™17.7E' ā€“ an interdisciplinary cooperation between dance, calligraphy, and the body in multimedia performance, began with a diary exchange between the artist and a friend, who shared their thoughts by writing in the same journal. During this ā€˜diary swappingā€™ period, they developed a semiotic system that only the two of them could understand. Later, the artist came across Nu Shu, the only written language in the world that exclusively women learned to write and read. The artist attempts to explore all the possible metaphors and meanings implied by Nu Shu. The performance 'Nu Shu GPS: 25 Ā°21ā€™00.5N, 111Ā°27ā€™17' attempts to bring this secret method of communication back to life among modern Chinese women. This interdisciplinary performance work employs a practical approach to art through a creative collaboration among experts from different fields: choreographers, dancers, lighting designers, programmers, etc. It attempts to apply the three stages of the art creation process (Praxis, Symbol, Presence) as the three different faces for a theory regarding this work

    Sorafenib for hepatocellular carcinoma patients beyond Milan criteria after orthotopic liver transplantation: a case control study

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    <p>Abstract</p> <p>Background</p> <p>Orthotopic liver transplantation (OLT) is one of the most effective treatments for patients with hepatocellular carcinoma (HCC) within the Milan criteria. However, for patients beyond these criteria, the recurrence rate is higher and the prognosis is worse. Sorafenib is the only drug showing survival benefits in advanced HCC patients; however, its role in patients beyond the Milan criteria after OLT remains unclear and requires further investigation.</p> <p>Methods</p> <p>As a case-control study, we retrospectively analyzed 17 Chinese patients beyond Milan criteria undergoing OLT for HCC. These patients were stratified into adjuvant (n = 5), palliative (n = 6), and control groups (n = 6).</p> <p>Results</p> <p>Nine of 11 patients who received sorafenib after OLT needed dose reduction due to more than grade 2 side effects. The disease-free survival rates for patients with or without adjuvant sorafenib were 100% versus 37.5% (p = 0.034) at 6 months, 66.7% versus 9.4% (p = 0.026) at 12 months, and 66.7% versus 0.0% (p = 0.011) at 18 months, respectively. The overall survival rates for patients in palliative and control groups were 66.7% versus 40.0% (p = 0.248) at 6 months, 66.7% versus 40.0% (p = 0.248) at 12 months, and 50.0% versus 20.0% (p = 0.17) at 18 months, respectively. Patients in the adjuvant group had better overall survival rates than those in the palliative and control groups (p = 0.031) at 24-month follow-up.</p> <p>Conclusions</p> <p>Adjuvant sorafenib could possibly extend both disease-free and overall survival for HCC patients beyond Milan criteria after OLT.</p
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