Case fatality: Rate, ratio, or risk? (letter)

postprin

The association of seasonal influenza vaccination with pandemic influenza H1N1 2009 infection

Letter to the editor; Comment on Vaccine. 2011 Nov 15, v. 29 n. 49, p. 9194-200In 2010 Skowronski and colleagues reported that seasonal influenza vaccine appeared to increase the risk of pandemic influenza H1N1 2009 (pH1N1) infection during the first pandemic wave in Canada [1]. They suggested a number of possible explanations for their unexpected finding: firstly, that the results were an artefact of selection bias or confounding; secondly, that the results were due to partial mediation through a biological mechanism; and thirdly, that the results were due to a direct immune mechanism, such as antibody dependent enhancement [1]. In a recent paper in Vaccine, Rosella and colleagues have investigated in detail the first of these possibilities, confirming that it is unlikely an unidentified confounder could have explained the findings [2]. © 2011 Elsevier Ltd.postprin

Household transmission of 2009 pandemic influenza A (H1N1): a systematic review and meta-analysis

BACKGROUND: During the 2009 influenza A (H1N1) pandemic, household transmission studies were implemented to better understand the characteristics of the transmission of the novel virus in a confined setting. METHODS: We conducted a systematic review and meta-analysis to assess and summarize the findings of these studies. We identified 27 articles, around half of which reported studies conducted in May and June 2009. RESULTS: In 13 of the 27 studies (48%) that collected respiratory specimens from household contacts, point estimates of the risk of secondary infection ranged from 3% to 38%, with substantial heterogeneity. Meta-regression analyses revealed that a part of the heterogeneity reflected varying case ascertainment and study designs. The estimates of symptomatic secondary infection risk, based on 20 studies identifying febrile acute respiratory illness among household contacts, also showed substantial variability, with point estimates ranging from 4% to 37%. CONCLUSIONS: Transmission of the 2009 pandemic virus in households appeared to vary among countries and settings, with differences in estimates of the secondary infection risk also partly due to differences in study designs.published_or_final_versio

Shadows and traces in bicategories

Traces in symmetric monoidal categories are well-known and have many applications; for instance, their functoriality directly implies the Lefschetz fixed point theorem. However, for some applications, such as generalizations of the Lefschetz theorem, one needs "noncommutative" traces, such as the Hattori-Stallings trace for modules over noncommutative rings. In this paper we study a generalization of the symmetric monoidal trace which applies to noncommutative situations; its context is a bicategory equipped with an extra structure called a "shadow." In particular, we prove its functoriality and 2-functoriality, which are essential to its applications in fixed-point theory. Throughout we make use of an appropriate "cylindrical" type of string diagram, which we justify formally in an appendix.Comment: 46 pages; v2: reorganized and shortened, added proof for cylindrical string diagrams; v3: final version, to appear in JHR

Mobilising knowledge in complex health systems: A call to action

Worldwide, policymakers, health system managers, practitioners and researchers struggle to use evidence to improve policy and practice. There is growing recognition that this challenge relates to the complex systems in which we work. The corresponding increase in complexity-related discourse remains primarily at a theoretical level. This paper moves the discussion to a practical level, proposing actions that can be taken to implement evidence successfully in complex systems. Key to success is working with, rather than trying to simplify or control, complexity. The integrated actions relate to co-producing knowledge, establishing shared goals and measures, enabling leadership, ensuring adequate resourcing, contributing to the science of knowledge-to-action, and communicating strategically. This is the final version of the article. It first appeared from Policy Press via http://dx.doi.org/10.1332/174426416X1471255375031

Freezing and chemical preservatives alter the stable isotope values of carbon and nitrogen of the Asiatic clam (Corbicula fluminea)

We tested the impacts of most common sample preservation methods used for aquatic sample materials on the stable isotope ratios of carbon and nitrogen in clams, a typical baseline indicator organism for many aquatic food web studies utilising stable isotope analysis (SIA). In addition to common chemical preservatives ethanol and formalin, we also assessed the potential impacts of freezing on δ¹³C and δ¹⁵N values and compared the preserved samples against freshly dried and analysed samples. All preservation methods, including freezing, had significant impacts on δ¹³C and δ¹⁵N values and the effects in general were greater on the carbon isotope values (1.3-2.2% difference) than on the nitrogen isotope values (0.9-1.0% difference). However, the impacts produced by the preservation were rather consistent within each method during the whole 1 year experiment allowing these to be accounted for, if clams are intended for use in retrospective stable isotope studies

Electrical stimulation devices for the prevention of venous thromboembolism: Preliminary studies of physiological efficacy and user satisfaction.

Introduction: Electrical stimulation could provide an alternative method for preventing venous thromboembolism in stroke patients. The purpose of this preliminary study was to explore the effects of electrical stimulation and intermittent pneumatic compression on enhancing lower limb venous return in healthy and chronic stroke patients and also to evaluate patient and nurse satisfaction. Methods: We investigated the effectiveness of two electrical stimulation devices: Geko (Firstkind Ltd, High Wycombe, UK) and Orthopaedic Microstim 2V2 (Odstock Medical Ltd, Salisbury, UK); and one intermittent pneumatic compression device: Huntleigh Flowstron Universal (Huntleigh Healthcare Ltd, Cardiff, UK). We recruited 12 healthy and 5 chronic stroke participants. The devices were fitted sequentially, and Doppler ultrasound measurements were taken. Eight patients and nurses were also recruited for a separate usability evaluation. Results: The electrical stimulation devices emulated the blood flow characteristics of intermittent pneumatic compression in both healthy and stroke participants provided that the intensity of electrical stimulation was sufficient. Patients and nurses also felt that the electrical stimulation devices were acceptable. Conclusions: Electrical stimulation may offer benefit as an alternative method for venous thromboembolism prevention in stroke patients. The apparent benefit is sufficient to warrant further investigation in a full powered randomised controlled trial

Field-study science classrooms as positive and enjoyable learning environments

We investigated differences between field-study classrooms and traditional science classrooms in terms of the learning environment and students’ attitudes to science, as well as the differential effectiveness of field-study classrooms for students differing in sex and English proficiency. A modified version of selected scales from the What Is Happening In this Class? questionnaire was used to assess the learning environment, whereas students’ attitudes were assessed with a shortened version of a scale from the Test of Science Related Attitudes. A sample of 765 grade 5 students from 17 schools responded to the learning environment and attitude scales in terms of both their traditional science classrooms and classrooms at a field-study centre in Florida. Large effect sizes supported the effectiveness of the field-studies classroom in terms of both the learning environment and student attitudes. Relative to the home school science class, the field-study class was considerably more effective for students with limited English proficiency than for native English speakers

Single-atom imaging of fermions in a quantum-gas microscope

Single-atom-resolved detection in optical lattices using quantum-gas microscopes has enabled a new generation of experiments in the field of quantum simulation. Fluorescence imaging of individual atoms has so far been achieved for bosonic species with optical molasses cooling, whereas detection of fermionic alkaline atoms in optical lattices by this method has proven more challenging. Here we demonstrate single-site- and single-atom-resolved fluorescence imaging of fermionic potassium-40 atoms in a quantum-gas microscope setup using electromagnetically-induced-transparency cooling. We detected on average 1000 fluorescence photons from a single atom within 1.5s, while keeping it close to the vibrational ground state of the optical lattice. Our results will enable the study of strongly correlated fermionic quantum systems in optical lattices with resolution at the single-atom level, and give access to observables such as the local entropy distribution and individual defects in fermionic Mott insulators or anti-ferromagnetically ordered phases.Comment: 7 pages, 5 figures; Nature Physics, published online 13 July 201

Impact of inhaled corticosteroids on growth in children with asthma: systematic review and meta-analysis

Background: Long-term inhaled corticosteroids (ICS) may reduce growth velocity and final height of children with asthma. We aimed to evaluate the association between ICS use of >12 months and growth. Methods: We initially searched MEDLINE and EMBASE in July 2013, followed by a PubMed search updated to December 2014. We selected RCTs and controlled observational studies of ICS use in patients with asthma. We conducted random effects meta-analysis of mean differences in growth velocity (cm/year) or final height (cm) between groups. Heterogeneity was assessed using the I2 statistic. Results: We found 23 relevant studies (twenty RCTs and three observational studies) after screening 1882 hits. Meta-analysis of 16 RCTs showed that ICS use significantly reduced growth velocity at one year follow-up (mean difference -0.48 cm/year (95% CI -0.66 to -0.29)). There was evidence of a dose-response effect in three RCTs. Final adult height showed a mean reduction of -1.20 cm (95% CI -1.90 cm to -0.50 cm) with budesonide versus placebo in a high quality RCT. Meta-analysis of two lower quality observational studies revealed uncertainty in the association between ICS use and final adult height, pooled mean difference -0.85 cm (95% CI -3.35 to 1.65). Conclusion: Use of ICS for >12 months in children with asthma has a limited impact on annual growth velocity. In ICS users, there is a slight reduction of about a centimeter in final adult height, which when interpreted in the context of average adult height in England (175 cm for men and 161 cm for women), represents a 0.7% reduction compared to non-ICS users