249 research outputs found

    An ion trap built with photonic crystal fibre technology

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    We demonstrate a surface-electrode ion trap fabricated using techniques transferred from the manufacture of photonic-crystal fibres. This provides a relatively straightforward route for realizing traps with an electrode structure on the 100 micron scale with high optical access. We demonstrate the basic functionality of the trap by cooling a single ion to the quantum ground state, allowing us to measure a heating rate from the ground state of 787(24) quanta/s. Variation of the fabrication procedure used here may provide access to traps in this geometry with trap scales between 100 um and 10 um.Comment: 6 pages, 4 figure

    CENÁRIOS DE TRANSFRONTEIRIZAÇÕES NA AMÉRICA DO SUL. ALGUNS EXEMPLOS DE PESQUISAS RECENTES

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    O artigo examina cenários de transfronterizações na América do Sul, entendida como uma região geopolítica. Regiões transfronteiriças e processos de transfronteirização podem ser compreendidos em diversos aspectos como reordenação de fluxos econômicos, pessoas cruzando limites de Estados, novas conexões de infraestruturas e de informações que tendem a produzir novas interações territoriais e territórios-rede. Apresenta-se cartografias multinacionais sul-americanas em grande detalhe de dados. Propõe-se o recorte regional da Região Transfronteiriça do Iguaçu onde ocorrem intensos fluxos transfronteiriços de diversos tipos, legais e ilegais. Por fim agrega-se à análise de processos de transfronteirizações recentes fluxos migratórios internacionais transcontinentais para o Brasil

    CENÁRIOS DE TRANSFRONTEIRIZAÇÕES NA AMÉRICA DO SUL. ALGUNS EXEMPLOS DE PESQUISAS RECENTES

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    O artigo examina cenários de transfronterizações na América do Sul, entendida como uma região geopolítica. Regiões transfronteiriças e processos de transfronteirização podem ser compreendidos em diversos aspectos como reordenação de fluxos econômicos, pessoas cruzando limites de Estados, novas conexões de infraestruturas e de informações que tendem a produzir novas interações territoriais e territórios-rede. Apresenta-se cartografias multinacionais sul-americanas em grande detalhe de dados. Propõe-se o recorte regional da Região Transfronteiriça do Iguaçu onde ocorrem intensos fluxos transfronteiriços de diversos tipos, legais e ilegais. Por fim agrega-se à análise de processos de transfronteirizações recentes fluxos migratórios internacionais transcontinentais para o Brasil

    Considerations for preparing a randomized population health intervention trial: lessons from a South African–Canadian partnership to improve the health of health workers

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    Background: Community-based cluster-randomized controlled trials (RCTs) are increasingly being conducted to address pressing global health concerns. Preparations for clinical trials are well-described, as are the steps for multi-component health service trials. However, guidance is lacking for addressing the ethical and logistic challenges in (cluster) RCTs of population health interventions in low- and middle-income countries. Objective: We aimed to identify the factors that population health researchers must explicitly consider when planning RCTs within North–South partnerships. Design: We reviewed our experiences and identified key ethical and logistic issues encountered during the pre-trial phase of a recently implemented RCT. This trial aimed to improve tuberculosis (TB) and Human Immunodeficiency Virus (HIV) prevention and care for health workers by enhancing workplace assessment capability, addressing concerns about confidentiality and stigma, and providing onsite counseling, testing, and treatment. An iterative framework was used to synthesize this analysis with lessons taken from other studies. Results: The checklist of critical factors was grouped into eight categories: 1) Building trust and shared ownership; 2) Conducting feasibility studies throughout the process; 3) Building capacity; 4) Creating an appropriate information system; 5) Conducting pilot studies; 6) Securing stakeholder support, with a view to scale-up; 7) Continuously refining methodological rigor; and 8) Explicitly addressing all ethical issues both at the start and continuously as they arise. Conclusion: Researchers should allow for the significant investment of time and resources required for successful implementation of population health RCTs within North–South collaborations, recognize the iterative nature of the process, and be prepared to revise protocols as challenges emerge

    Task shifting and integration of HIV care into primary care in South Africa: The development and content of the streamlining tasks and roles to expand treatment and care for HIV (STRETCH) intervention

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    Background: Task shifting and the integration of human immunodeficiency virus (HIV) care into primary care services have been identified as possible strategies for improving access to antiretroviral treatment (ART). This paper describes the development and content of an intervention involving these two strategies, as part of the Streamlining Tasks and Roles to Expand Treatment and Care for HIV (STRETCH) pragmatic randomised controlled trial. Methods: Developing the intervention: The intervention was developed following discussions with senior management, clinicians, and clinic staff. These discussions revealed that the establishment of separate antiretroviral treatment services for HIV had resulted in problems in accessing care due to the large number of patients at ART clinics. The intervention developed therefore combined the shifting from doctors to nurses of prescriptions of antiretrovirals (ARVs) for uncomplicated patients and the stepwise integration of HIV care into primary care services. Results: Components of the intervention: The intervention consisted of regulatory changes, training, and guidelines to support nurse ART prescription, local management teams, an implementation toolkit, and a flexible, phased introduction. Nurse supervisors were equipped to train intervention clinic nurses in ART prescription using outreach education and an integrated primary care guideline. Management teams were set up and a STRETCH coordinator was appointed to oversee the implementation process. Discussion: Three important processes were used in developing and implementing this intervention: active participation of clinic staff and local and provincial management, educational outreach to train nurses in intervention sites, and an external facilitator to support all stages of the intervention rollout

    The relationship between ADHD and key cognitive phenotypes is not mediated by shared familial effects with IQ

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    Background Twin and sibling studies have identified specific cognitive phenotypes that may mediate the association between genes and the clinical symptoms of attention deficit hyperactivity disorder (ADHD). ADHD is also associated with lower IQ scores. We aimed to investigate whether the familial association between measures of cognitive performance and the clinical diagnosis of ADHD is mediated through shared familial influences with IQ. Method Multivariate familial models were run on data from 1265 individuals aged 6-18 years, comprising 920 participants from ADHD sibling pairs and 345 control participants. Cognitive assessments included a four-choice reaction time (RT) task, a go/no-go task, a choice-delay task and an IQ assessment. The analyses focused on the cognitive variables of mean RT (MRT), RT variability (RTV), commission errors (CE), omission errors (OE) and choice impulsivity (CI). Results Significant familial association (rF) was confirmed between cognitive performance and both ADHD (rF=0.41-0.71) and IQ (rF=−0.25 to −0.49). The association between ADHD and cognitive performance was largely independent (80-87%) of any contribution from etiological factors shared with IQ. The exception was for CI, where 49% of the overlap could be accounted for by the familial variance underlying IQ. Conclusions The aetiological factors underlying lower IQ in ADHD seem to be distinct from those between ADHD and RT/error measures. This suggests that lower IQ does not account for the key cognitive impairments observed in ADHD. The results have implications for molecular genetic studies designed to identify genes involved in ADH
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