Efficient C-Phase gate for single-spin qubits in quantum dots

Two-qubit interactions are at the heart of quantum information processing. For single-spin qubits in semiconductor quantum dots, the exchange gate has always been considered the natural two-qubit gate. The recent integration of magnetic field or g-factor gradients in coupled quantum dot systems allows for a one-step, robust realization of the controlled phase (C-Phase) gate instead. We analyze the C-Phase gate durations and fidelities that can be obtained under realistic conditions, including the effects of charge and nuclear field fluctuations, and find gate error probabilities of below 10-4, possibly allowing fault-tolerant quantum computation.Comment: 5 pages, 3 figure

Recurrent Respiratory Papillomatosis

A papilomatose respiratória recorrente da criança é uma doença rara, mas potencialmente ameaçadora da vida, e que atinge o trato respiratório com predilecção pela laringe e traqueia. É causada pelo papiloma-vírus humano (tipo 6 e 11). É uma das causas de rouquidão e obstrução da via aérea. É necessário um elevado grau de suspeição diagnóstica, tendo em conta as várias formas de apresentação. Apresenta-se o caso de uma criança de quatro anos de idade, com antecedentes de papilomatose laríngea, internada por obstrução respiratória alta grave e necessidade de traqueotomia de emergência. A tipagem viral realizada posteriormente revelou tratar-se do papilomavírus humano tipo 11 e 72. Nos catorze meses seguintes foi submetida a seis intervenções cirúrgicas, inicialmente por técnicas convencionais e laser de CO2, e de seguida utilizando o novo método de microdebridador e aplicação de cidofovir intralesional. Trata-se de um caso ilustrativo de doença extremamente agressiva, que pôs em risco a vida da criança e com óbvia repercussão na sua qualidade de vida. A papilomatose respiratória recorrente, embora rara, deve estar presente nos diagnósticos diferenciais de estridor na criança, de modo a prevenir o crescimento de papilomas e a consequente obstrução grave das vias aéreas

Body mass index and airway hyper-responsiveness in individuals without respiratory disease

BACKGROUND: Overweight and obesity are major health issues in Western societies. They are related with a higher risk of different co-morbidities but their relationship with airway hyperresponsiveness (AHR) is still under discussion. Nevertheless, they are related to higher severity in asthma and other respiratory diseases. The aim of the study was to analyze the AHR in individuals with normal lung function without respiratory disorders, according to body mass index (BMI) calculation. METHODS: We performed clinical observation and basal lung function tests (LFT) in 595 consecutive individuals in order to exclude respiratory disease. 377 individuals fulfilled the criteria of normal values according international guidelines. They were submitted to standardized treadmill exercise test followed by bronchodilator test. FVC, FEV1, FEF 25/75, RV and Raw were obtained at different conditions according to BMI groups (I: lean; II: normal; III: overweight; IV obese). RESULTS: 55.2% of the sample was overweight or obese, and a signficant relationship was found with female gender and older ages (p=0.0046 and p<0.0001 respectively). The positive response to exercise test or bronchodilator beta2 agonists was not significantly frequent compared with the other groups. In obese individuals the exercise markedly reduced basal Raw and increased FEF 25/75. Lean individuals showed higher basal values of RV that was reduced upon exercise. Response to 12 agonists showed no differences according to weight biotypes. CONCLUSION: BMI hampers lung function in normal individuals, and seems not to be related to AHR. Regular exercise should be encouraged in overweight and obese individuals, since it increases their bronchial permeability as shown in lower frequency of positive exercise tests. The same is advisable for lean individuals for different reasons. Their increased basal RV and Raw improve upon exercise. Despite overweight and obesity are being related to a low-grade of basal systemic inflammation, there was no association with a higher basal bronchial hyperresponsiveness in these individuals

Streptococcal tonsillitis as a cause of urticaria Tonsillitis and urticaria

BACKGROUND: The primary role of infections in chronic urticaria (CU) is controversial. We hypothesised that streptococcal tonsillitis (ST) could be a primary cause of CU or acute recurrent urticaria (ARU). METHODS: Retrospective study of 14 outpatients observed between January 2000 and December 2009, with CU/ARU and clinical and/or laboratorial suspicion of an aetiopathogenic link with ST. Clinical history, objective examination and laboratorial study were looked for. Three groups were defined: spontaneous resolution of urticaria, resolution after tonsillectomy, and still symptomatic. RESULTS: In these patients, a causal relationship between ST and urticaria is supported by: markers of streptococcal infection, the perception of a clinical relationship between tonsillitis and urticaria, the decrease of urticaria severity with early antibiotherapy to tonsillitis and urticaria resolution after tonsillectomy. CONCLUSIONS: Our study encourages the investigation of tonsillitis in these otherwise idiopathic patients, especially until young adulthood and even in the absence of any symptoms

Parasitismo e desenvolvimento de Trichospilus diatraeae (Hymenoptera: Eulophidae) em pupas de Bombyx mori (Lepidoptera: Bombycidae) em diferentes temperaturas.

SICONBIOL 2011