1,625 research outputs found

    Exploration of Finite 2D Square Grid by a Metamorphic Robotic System

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    We consider exploration of finite 2D square grid by a metamorphic robotic system consisting of anonymous oblivious modules. The number of possible shapes of a metamorphic robotic system grows as the number of modules increases. The shape of the system serves as its memory and shows its functionality. We consider the effect of global compass on the minimum number of modules necessary to explore a finite 2D square grid. We show that if the modules agree on the directions (north, south, east, and west), three modules are necessary and sufficient for exploration from an arbitrary initial configuration, otherwise five modules are necessary and sufficient for restricted initial configurations

    A Language and Hardware Independent Approach to Quantum-Classical Computing

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    Heterogeneous high-performance computing (HPC) systems offer novel architectures which accelerate specific workloads through judicious use of specialized coprocessors. A promising architectural approach for future scientific computations is provided by heterogeneous HPC systems integrating quantum processing units (QPUs). To this end, we present XACC (eXtreme-scale ACCelerator) --- a programming model and software framework that enables quantum acceleration within standard or HPC software workflows. XACC follows a coprocessor machine model that is independent of the underlying quantum computing hardware, thereby enabling quantum programs to be defined and executed on a variety of QPUs types through a unified application programming interface. Moreover, XACC defines a polymorphic low-level intermediate representation, and an extensible compiler frontend that enables language independent quantum programming, thus promoting integration and interoperability across the quantum programming landscape. In this work we define the software architecture enabling our hardware and language independent approach, and demonstrate its usefulness across a range of quantum computing models through illustrative examples involving the compilation and execution of gate and annealing-based quantum programs

    Secondary giant cell glioblastoma in a multiple drug abuser - simple association or ethiopathogenic correlation? Case presentation and literature review

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    Experimental investigations have shown that drug abuse initiates a cascade of pathophysiological events including toxic and hypoxic-ischemic injury on neurons, microglia and astrocytes, which finally lead to widespread disturbances in the brain. There are many reports about the psychiatric and neurologic effects of multiple drug abuse, but only a few clinical studies reporting possible correlation between recreational illicit drugs and gliomas. In this paper we present the case of a 40 years-old male patient, with a long history (almost ten years) of multiple drug abuse, including cocaine, heroin, marijuana, ethnobotanical drugs and nicotine, who was diagnosed and surgically treated for a supratentorial secondary giant cell glioblastoma (sgcGB) developed in a diffuse astrocytoma NOS. Depending on the type of the illicit drug used by the patient and the moment of life he used them, the morphological features identified in the histological samples of our patient confirmed the gliomagenesis effect of chronic multiple drug abuse, but also its inhibitory effects on tumour cells growth. This was due to the fact that although the tumour was large in size and caused brain sub-falcine herniation, the patient reported the onset of seizures only late in the evolution. In conclusion, the diagnosis of a brain tumour should take into consideration not only patient's clinical and imaging data, but also his lifestyle, especially his addiction to recreational drugs

    Parity Mixed Doublets in A = 36 Nuclei

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    The γ\gamma-circular polarizations (PγP_{\gamma}) and asymmetries (AγA_{\gamma}) of the parity forbidden M1 + E2 γ\gamma-decays: 36Cl∗(Jπ=2−;T=1;Ex=1.95^{36}Cl^{\ast} (J^{\pi} = 2^{-}; T = 1; E_{x} = 1.95 MeV) →\rightarrow 36Cl(Jπ=2+;T=1;g.s.)^{36}Cl (J^{\pi} = 2^{+}; T = 1; g.s.) and 36Ar∗(Jπ=2−;T=0;Ex=4.97^{36}Ar^{\ast} (J^{\pi} = 2^{-}; T = 0; E_{x} = 4.97 MeV) →\rightarrow 36Ar∗(Jπ=2+;T=0;Ex=1.97^{36}Ar^{\ast} (J^{\pi} = 2^{+}; T = 0; E_{x} = 1.97 MeV) are investigated theoretically. We use the recently proposed Warburton-Becker-Brown shell-model interaction. For the weak forces we discuss comparatively different weak interaction models based on different assumptions for evaluating the weak meson-hadron coupling constants. The results determine a range of PγP_{\gamma} values from which we find the most probable values: PγP_{\gamma} = 1.1⋅10−41.1 \cdot 10^{-4} for 36Cl^{36}Cl and PγP_{\gamma} = 3.5⋅10−43.5 \cdot 10^{-4} for 36Ar^{36}Ar.Comment: RevTeX, 17 pages; to appear in Phys. Rev.
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