How often should we monitor for reliable detection of atrial fibrillation recurrence? Efficiency considerations and implications for study design

OBJECTIVE: Although atrial fibrillation (AF) recurrence is unpredictable in terms of onset and duration, current intermittent rhythm monitoring (IRM) diagnostic modalities are short-termed and discontinuous. The aim of the present study was to investigate the necessary IRM frequency required to reliably detect recurrence of various AF recurrence patterns. METHODS: The rhythm histories of 647 patients (mean AF burden: 12±22% of monitored time; 687 patient-years) with implantable continuous monitoring devices were reconstructed and analyzed. With the use of computationally intensive simulation, we evaluated the necessary IRM frequency to reliably detect AF recurrence of various AF phenotypes using IRM of various durations. RESULTS: The IRM frequency required for reliable AF detection depends on the amount and temporal aggregation of the AF recurrence (p<0.0001) as well as the duration of the IRM (p<0.001). Reliable detection (>95% sensitivity) of AF recurrence required higher IRM frequencies (>12 24-hour; >6 7-day; >4 14-day; >3 30-day IRM per year; p<0.0001) than currently recommended. Lower IRM frequencies will under-detect AF recurrence and introduce significant bias in the evaluation of therapeutic interventions. More frequent but of shorter duration, IRMs (24-hour) are significantly more time effective (sensitivity per monitored time) than a fewer number of longer IRM durations (p<0.0001). CONCLUSIONS: Reliable AF recurrence detection requires higher IRM frequencies than currently recommended. Current IRM frequency recommendations will fail to diagnose a significant proportion of patients. Shorter duration but more frequent IRM strategies are significantly more efficient than longer IRM durations. CLINICAL TRIAL REGISTRATION URL: Unique identifier: NCT00806689

International Reserves Management and the Current Account

The paper assesses the costs and benefits of active international reserve management (IRM), shedding light on the question of how intense should IRM be for an emerging market. In principle, an active IRM strategy could lower real exchange rate volatility induced by terms of trade shocks; provide self insurance against sudden stops; reduce the speed of adjustment of the current account; and even allow for higher growth if it fosters exports (“mercantilist” motive). The message of the report is mixed – management of reserves is not a panacea. The mercantilist case for hoarding international reserves, as an ingredient of an export led growth strategy, is dubious. Done properly, IRM augments macro economic management in turbulent times, mitigating the impact of external adverse shocks and allowing for a smoother current account adjustment. These benefits are especially important for commodity exporting countries, and countries with limited financial development.

Fingerprinting the magnetic behavior of antiferromagnetic nanostructures using remanent magnetization curves

Antiferromagnetic (AF) nanostructures from Co3O4, CoO and Cr2O3 were prepared by the nanocasting method and were characterized magnetometrically. The field and temperature dependent magnetization data suggests that the nanostructures consist of a core-shell structure. The core behaves as a regular antiferromagnet and the shell as a two-dimensional diluted antiferromagnet in a field (2d DAFF) as previously shown on Co3O4 nanowires [Benitez et al., Phys. Rev. Lett. 101, 097206 (2008)]. Here we present a more general picture on three different material systems, i.e. Co3O4, CoO and Cr2O3. In particular we consider the thermoremanent (TRM) and the isothermoremanent (IRM) magnetization curves as "fingerprints" in order to identify the irreversible magnetization contribution originating from the shells. The TRM/IRM fingerprints are compared to those of superparamagnetic systems, superspin glasses and 3d DAFFs. We demonstrate that TRM/IRM vs. H plots are generally useful fingerprints to identify irreversible magnetization contributions encountered in particular in nanomagnets.Comment: submitted to PR

Adoption of a New Maize and Production Efficiency in Western Kenya

Declining yields of maize as a result of Striga infestation has necessitated a new technology known as Imazapyr-resistant maize (IRM) to contain the problem. As a result, research and development initiatives with substantial participation of the private sector to transfer this new technology to farmers have been made in western Kenya. This study therefore assesses the adoption of IRM variety and efficiency levels of farmers in western Kenya. A multi-stage sampling technique was used to select a total of 600 households from Nyanza and Western provinces for this study. Tobit model and stochastic production frontier analysis were the analytical methods. Results show that age, education, maize production gap, risk, contact with extension agents, lack of seeds, membership in social group, effective pathway for IRM dissemination and compatibility of the technology are the variables that were found to be significant (P<0.05) in shaping the decisions of households on whether to adopt or not. The study reveals that the mean technical efficiency of maize production of sampled farmers is 70% indicating some inefficiencies of maize production in western Kenya. Also, adoption of IRM significantly increased frontier maize output (P<0.01); household size decreased inefficiency along with farm size. It was recommended that efforts to increase adoption of IRM for enhanced farm efficiency should focus on farmers’ education, farming experience and access to information and farm basic inputs.IRM technology, efficiency, stochastic production frontier, Tobit model, Crop Production/Industries,

Bt Corn Farmer Compliance with Insect Resistance Management Requirements: Results from the 2002 Minnesota and Wisconsin Farm Polls

The U.S. Environmental Protection Agency (EPA) reregistered Bt corn in 2001 with mandatory Insect Resistance Management (IRM) requirements in order to promote sustainable use by farmers. Since then studies report IRM compliance rates ranging from 80 to 90 percent. Using survey data from Minnesota and Wisconsin, we show that previous compliance rate estimates are likely too high because they do not use a comprehensive measure for compliance. With a more comprehensive measure, we find compliance rates ranging between 60 to 75 percent.Bt corn, compliance, Insect Resistance Management, refuge, Crop Production/Industries,

A survey of public sector information resource management in Australia

The concept of Information Resource Management (IRM) was introduced in the mid-1970?s bythe United States federal government as part of its attempt to reduce the paperwork burden on the general public. Since then, the concept of IRM has evolved and taken on many meanings and diverse interpretations ranging from technical perspectives to ?Information Management perspectives. These diverse interpretations, at least in the Australian context, have held back the successful implementation of IRM in practice. As part of a larger program of research on IRM, a survey of IS/IT executives in some national and state public sector organisations was conducted.Despite the existence of a number of state and federal government policy documents relating to IRM, the survey revealed a lack of penetration of IRM in Australian public sector organisations, a pattern of mixed success and even a lack of awareness of IRM. Factors involved in the success or failure of IRM included awareness of IRM, existence of a CIO role, top-level (CEO) endorsement and strategic planning

Distribution of RH and Kell (K) blood group antigens among blood donors in a tertiary care hospital of Jammu region, India

Background: Knowledge about the frequency of red cell antigen phenotype is very important for the creation of donor data bank and to minimize the risk of alloimmunization. This requires the determination of immunological characteristics of blood products and blood recipients by performing phenotyping of clinically significant blood group antigens. The aims and objectives were to study the distribution of Rh and Kell (K) antigen among blood donors of different ethnic groups in a tertiary care hospital.Methods: This was prospective observational cross sectional one-point analysis study which was carried out over a period of one year with effect from November 2015 to October 2016 in the Postgraduate Department of Immunohematology and Blood Transfusion Medicine, Shri Maharaja Gulab Singh (SMGS) Hospital, Government Medical College, Jammu and Kashmir, India. It comprised of voluntary and replacement donors and categorized into different ethnic groups i.e Dogras, Gujjar Muslims, Non-Gujjar Muslims, Kashmiri Pandits, Sikhs and Christian. Donors selection criteria was as per Drug and Cosmetic Act.Results: A total of 500 (Five hundred) blood samples from the donors of all blood groups were typed for the presence of Rh (D, C, E, c, e) and Kell (K) antigens. Out of these 500 samples, 420 were antigen typed by conventional tube technique and 80 samples were typed by column agglutination technique using glass beads. As per ethnicity, maximum donors were Dogras (74%) followed by Non-Gujjar Muslims (9.4%), Gujjar Muslims (9%), Sikhs (5.6%), Kashmiri Pandits (1.4%) and Christians were the least in frequency (0.6%). On phenotyping for Rh and Kell antigens ‘e’ antigen have the ubiquitous distribution and was found to have the highest frequency 486 (97.2%) followed by ‘D’ antigen 472 (94.4%), ‘C’ antigen 426 (85.2%), ‘c’ antigen 320 (64.0%) and ‘E’ antigen 103 (20.6%). Overall frequency of Kell (K) antigen was 2.6%.Conclusions: Knowledge of red cell antigen phenotype frequencies in a population with different ethnic groups can help in creating donor data bank and database for the distribution of blood groups for preparing inhouse cell panels and providing proper antigen compatible blood for patients with multiple alloantibodies and also reduce the risk of RBC antigen alloimmunization along with their complications