19 research outputs found

    Compilation of Fault-Tolerant Quantum Heuristics for Combinatorial Optimization

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    Here we explore which heuristic quantum algorithms for combinatorial optimization might be most practical to try out on a small fault-tolerant quantum computer. We compile circuits for several variants of quantum-accelerated simulated annealing including those using qubitization or Szegedy walks to quantize classical Markov chains and those simulating spectral-gap-amplified Hamiltonians encoding a Gibbs state. We also optimize fault-tolerant realizations of the adiabatic algorithm, quantum-enhanced population transfer, the quantum approximate optimization algorithm, and other approaches. Many of these methods are bottlenecked by calls to the same subroutines; thus, optimized circuits for those primitives should be of interest regardless of which heuristic is most effective in practice. We compile these bottlenecks for several families of optimization problems and report for how long and for what size systems one can perform these heuristics in the surface code given a range of resource budgets. Our results discourage the notion that any quantum optimization heuristic realizing only a quadratic speedup achieves an advantage over classical algorithms on modest superconducting qubit surface code processors without significant improvements in the implementation of the surface code. For instance, under quantum-favorable assumptions (e.g., that the quantum algorithm requires exactly quadratically fewer steps), our analysis suggests that quantum-accelerated simulated annealing requires roughly a day and a million physical qubits to optimize spin glasses that could be solved by classical simulated annealing in about 4 CPU-minutes

    Eliminação transepidérmica de parasitas na doença de Jorge Lobo Transepidermal elimination of parasites in Jorge Lobo's disease

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    FUNDAMENTOS: A eliminação transepidérmica de parasitas (ETEP) tem sido pouco estudada na doença de Jorge Lobo. OBJETIVOS: Identificar aspectos morfológicos da ETEP na doença de Jorge Lobo. MÉTODOS: Recortes de biópsias de doença de Jorge Lobo emblocados em parafina foram corados pela hematoxilina-eosina e examinados. Considerou-se como ETEP, exclusivamente, a presença de parasitas em estruturas epidérmicas. RESULTADOS: Foram incluídas no estudo 40 biópsias de 37 pacientes (31 homens e seis mulheres, média de idade 51,03 anos, variação 29-80 anos) realizadas em um período de 37 anos (1967-2003), das quais foram obtidos 511 cortes (média de 12,77 cortes por caso, variação 2-39 cortes por caso). Observou-se ETEP em 110/511 (21,52%) e não se observou em 401/511 cortes (78,48%) (p < 0,0001). Em relação aos pacientes (37), em 15 se verificaram aspectos consistentes com ETEP (40,5%), ao passo que, em 22 deles (59,5%), isso não foi observado (p > 0,05). Os parasitas dispunham-se em infundíbulos hiperplásicos, formando catênulas, ou como unidades isoladas, associados ou não a células inflamatórias. CONCLUSÕES: Aspectos consistentes com ETEP, embora observados em número estatisticamente não significante de pacientes da amostra (p > 0,05), sugerem que, na doença de Jorge Lobo, o fenômeno, invariavelmente, ocorra através do epitélio infundibular. Estudos futuros serão necessários para avaliar sua eventual importância na epidemiologia da micose.<br>BACKGROUND: Few studies have focussed on the transepidermal elimination of parasites in Jorge Lobo's disease (lobomycosis). OBJECTIVE: To identify the morphological features of the transepidermal elimination of parasites in lobomycosis. METHODS: Sections were obtained from paraffin-embedded biopsy specimens of patients with lobomycosis and stained with hematoxylin-eosin for microscopic examination. Only the presence of parasites in epidermal structures was considered to constitute transepidermal elimination. RESULTS: Forty biopsies from 37 patients were included in the study (31 males and 6 females). The mean age of patients was 51.03 years (range 29-80 years). Biopsies performed over a period of 37 years (1967-2003) were used, from which 511 sections were obtained (a mean of 12.77 sections per case; range 2-39 sections per case). Transepidermal elimination of parasites was found in 110/511 (21.52%) and was absent in 401/511 sections (78.48%) (p<0.0001). Features consistent with the phenomenon were found in 15/37 patients (40.5%) and were absent in 22/37 (59.5%) (p>0.05). Parasites in the epidermis were detected within hyperplastic infundibula, either connected in chains or as isolated units, associated or not with inflammatory cells. CONCLUSION: Features consistent with transepidermal elimination of parasites were found in a statistically nonsignificant number of patients in the sample (p>0.05), suggesting that in Jorge Lobo's disease, this phenomenon invariably occurs through the infundibular epithelium. Future studies are required to evaluate the significance of this finding in the epidemiology of mycosis

    Teste ergométrico e o Holter de 24 horas na detecção de arritmias ventriculares complexas em diferentes estádios da cardiopatia chagásica crônica Exercise testing and 24 hours Holter monitoring in the detection of complex ventricular arrhythmias in different stages of chronic Chagas' heart disease

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    Comparou-se o teste ergométrico com Holter de 24 horas na detecção de arritmias ventriculares complexas em diferentes estádios da cardiopatia chagásica crônica. Avaliados 71 pacientes sem outras doenças associadas, idade=51±10,3, metade mulheres. Divididos em quatro grupos conforme o grau de acometimento cardíaco. A estatística esta discriminada no corpo do trabalho. Ao Holter, no grupo IA as arritmias ventriculares complexas foram detectadas em 4,3%, IB em 25%, II em 55% e no grupo III em 90%. Nos grupos II e III não houve diferença entre os exames na detecção de arritmias ventriculares complexas (p=NS). Nos grupos IA e IB, houve uma concordância de 100% no teste ergométrico na não detecção de arritmias ventriculares complexas entre dois observadores. No grupo II, a concordância foi de 70% (kappa=0,368, p=0,003) e de 90% (kappa=0,78, p=0,002) no grupo III. Foi observado diferenças na presença de arritmias ventriculares complexas entre os pacientes dos grupos em fase inicial e avançada da cardiopatia chagásica crônica. Nos pacientes dos grupos II e III não houve diferença entre os dois exames na detecção das arritmias ventriculares complexas. Pacientes dos grupos IA e IB é razoável indicar Holter e/ou o teste ergométrico na ocorrência de progressão da doença.<br>To detect complex ventricular arrhythmias in different stages of chronic chagasic cardiopathy, the results of exercise testing to 24 hours Holter monitoring have been compared. We evaluated a group of 71 patients, half women, aged 51±10.3, with no others associated diseases. These patients were separated in 4 groups according to degree of cardiac involvement. Statistical data can be found elsewhere in the study. In group IA, Holter monitoring detected 4.3% of complex ventricular arrhythmias, group IB 25%, group II 55% and group III 90%. We found no difference between Holter and exercise testing in the detection of complex ventricular arrhythmias in groups II and III (p = ns). In groups IA and IB we found 100% concordance, concerning the no detection of complex ventricular arrhythmias by exercise testing seen by two independent examiners. In group II there was a 70% concordance (kappa=0.368, p=0.003) and 90% in group III (kappa=0.78, p=0.002). Different results were found, concerning the presence of complex ventricular arrhythmias, among patients in the initial and advanced stages of chronic chagasic cardiopathy. In groups II and III we found no difference between the two methods in the detection of complex ventricular arrhythmias. It seems reasonable to recommend either Holter on exercise testing in groups IA and IB if progression of disease is noticed
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