Fault-tolerance thresholds for the surface code with fabrication errors

The construction of topological error correction codes requires the ability to fabricate a lattice of physical qubits embedded on a manifold with a non-trivial topology such that the quantum information is encoded in the global degrees of freedom (i.e. the topology) of the manifold. However, the manufacturing of large-scale topological devices will undoubtedly suffer from fabrication errors---permanent faulty components such as missing physical qubits or failed entangling gates---introducing permanent defects into the topology of the lattice and hence significantly reducing the distance of the code and the quality of the encoded logical qubits. In this work we investigate how fabrication errors affect the performance of topological codes, using the surface code as the testbed. A known approach to mitigate defective lattices involves the use of primitive SWAP gates in a long sequence of syndrome extraction circuits. Instead, we show that in the presence of fabrication errors the syndrome can be determined using the supercheck operator approach and the outcome of the defective gauge stabilizer generators without any additional computational overhead or the use of SWAP gates. We report numerical fault-tolerance thresholds in the presence of both qubit fabrication and gate fabrication errors using a circuit-based noise model and the minimum-weight perfect matching decoder. Our numerical analysis is most applicable to 2D chip-based technologies, but the techniques presented here can be readily extended to other topological architectures. We find that in the presence of 8% qubit fabrication errors, the surface code can still tolerate a computational error rate of up to 0.1%.Comment: 10 pages, 15 figure

Intake, growth and meat quality of steers given diets based on varying proportions of maize silage and grass silage

Simmental × Holstein-Friesian steers were offered four forage diets. These comprised grass silage (G); proportionately 0·67 grass silage, proportionately 0·33 maize silage (GGM); 0·33 grass silage, 0·67 maize silage ( MMG); maize silage ( M) from 424 (s.d. = 11·5) kg to slaughter at a minimum weight of 560 kg. Forages were mixed and offered ad libitum. Steers were offered 2 kg of a concentrate daily, the concentrate being formulated such that all steers had similar crude protein intakes across dietary treatments. A sample of steers was slaughtered at the beginning of the experimental period to allow the calculation of the rate of gain of the carcass and its components. Carcass dissection of a sample of steers allowed the development of a prediction equation of carcass composition based on thoracic limb dissection of all carcasses. Forage dry matter intake and live-weight gain increased linearly as maize silage replaced grass silage in the forage mixture, resulting in improvements in food conversion ratio (all P = 0·001). Killing-out proportion increased with maize silage inclusion ( P < 0·001) but fat and conformation scores did not differ significantly between diets. However, increasing maize inclusion in the diet resulted in a greater weight ( P = 0·05) and proportion ( P = 0·008) of fat in the carcass, and significant increases in internal fat deposition. The inclusion of maize led to a progressive increase in the daily gains of carcass ( P < 0·001), and significant increases in the daily gains of both fat ( P < 0·001) and lean tissue ( P < 0·001). Fat colour was more yellow in cattle given diets G and GGM than diets MMG and M ( P < 0·001) and colour intensity was lower on diet M than the other three diets ( P < 0·001). There were no significant differences in any aspects of eating quality between diets. Therefore, maize silage has the potential to reduce the time taken for finishing beef animals to achieve slaughter weight with no apparent detrimental effects on subsequent meat quality

“On the dialect of Norfolk”

Glosario. -- Norfolk. -- Pertenece a la colección Varia del Salamanca Corpus. -- Sir Thomas Browne, 1605-1682. -- "On the dialect of Norfolk". -- 1684.[ES] Listado de palabras del dialecto de Norfolk. [EN] List of Norfolk dialect words

Student Affairs in Canada in 2013 Perceptions, Trends, and an Outlook toward the Future

Chief Student Affairs Officers (CSAOs) are senior-level student affairs personnel. In 2011, 33 CSAOs responded to a national survey and provided a professional perspective on field development, student services, as well as predicted five-year trends for student affairs. In 2013, 17 CSAOs responded to the same survey and provided further information on these topics. Results indicated that attitudes towards diversity and technology remained stable between 2011 and 2013. We established that CSAOs have less positive attitudes towards research, evaluation, and assessment than they do towards communication and leadership. Here, we discuss at length the implications of these finding, as well as the potential for research into student affairs. In addition, we examine the continued professionalization of the CSAO field and note that research into CSAOs should be proactive instead of reactive. &nbsp;Les directeurs des affaires étudiantes sont des membres du personnel des affaires étudiantes aux niveaux supérieurs. En 2011, 33 de ces directeurs ont répondu à un sondage national et fourni une perspective professionnelle sur la mise en valeur de leur domaine, sur les services aux étudiants, ainsi que sur leurs prédictions des tendances des cinq prochaines années pour les affaires étudiantes. En 2013, 17 directeurs ont répondu au même sondage et ont fourni plus de données sur ces mêmes sujets. Les résultats indiquaient que les attitudes envers la diversité et la technologie étaient demeurées stables entre 2011 et 2013. Nous avons pu établir que les directeurs présentent des attitudes moins positives envers la recherche, l’évaluation et les épreuves, qu’envers la communication et le leadership. Nous nous attardons ici sur les implications de ces découvertes, de même que sur leur potentiel pour la recherche au sujet des affaires étudiantes. Nous discutons aussi de la professionnalisation du domaine des directeurs des affaires étudiantes et notons que la recherche au sujet des directeurs doit être proactive plutôt que réactive

An interprofessional nurse-led mental health promotion intervention for older home care clients with depressive symptoms.

BackgroundDepressive symptoms in older home care clients are common but poorly recognized and treated, resulting in adverse health outcomes, premature institutionalization, and costly use of health services. The objectives of this study were to examine the feasibility and acceptability of a new six-month interprofessional (IP) nurse-led mental health promotion intervention, and to explore its effects on reducing depressive symptoms in older home care clients (≥ 70 years) using personal support services.MethodsA prospective one-group pre-test/post-test study design was used. The intervention was a six-month evidence-based depression care management strategy led by a registered nurse that used an IP approach. Of 142 eligible consenting participants, 98 (69%) completed the six-month and 87 (61%) completed the one-year follow-up. Outcomes included depressive symptoms, anxiety, health-related quality of life (HRQoL), and the costs of use of all types of health services at baseline and six-month and one-year follow-up. An interpretive descriptive design was used to explore clients', nurses', and personal support workers' perceptions about the intervention's appropriateness, benefits, and barriers and facilitators to implementation.ResultsOf the 142 participants, 56% had clinically significant depressive symptoms, with 38% having moderate to severe symptoms. The intervention was feasible and acceptable to older home care clients with depressive symptoms. It was effective in reducing depressive symptoms and improving HRQoL at six-month follow-up, with small additional improvements six months after the intervention. The intervention also reduced anxiety at one year follow-up. Significant reductions were observed in the use of hospitalization, ambulance services, and emergency room visits over the study period.ConclusionsOur findings provide initial evidence for the feasibility, acceptability, and sustained effects of the nurse-led mental health promotion intervention in improving client outcomes, reducing use of expensive health services, and improving clinical practice behaviours of home care providers. Future research should evaluate its efficacy using a randomized clinical trial design, in different settings, with an adequate sample of older home care recipients with depressive symptoms.Trial registrationClinicaltrials.gov identifier: NCT01407926