Variety, complexity and economic development

We propose a combinatorial model of economic development. An economy develops by acquiring new capabilities allowing for the production of an ever greater variety of products with an increasing complexity. Taking into account that economies abandon the least complex products as they develop over time, we show that variety first increases and then decreases in the course of economic development. This is consistent with the empirical pattern known as ‘the hump’. Our results question the common association of variety with complexity. We further discuss the implications of our model for future research

Identification and functional characterisation of Complement Regulator Acquiring Surface Protein-1 of serum resistant Borrelia garinii OspA serotype 4

<p>Abstract</p> <p>Background</p> <p><it>B. burgdorferi </it>sensu lato (sl) is the etiological agent of Lyme borreliosis in humans. Spirochetes have adapted themselves to the human immune system in many distinct ways. One important immune escape mechanism for evading complement activation is the binding of complement regulators Factor H (CFH) or Factor H-like protein1 (FHL-1) to Complement Regulator-Acquiring Surface Proteins (CRASPs).</p> <p>Results</p> <p>We demonstrate that <it>B. garinii </it>OspA serotype 4 (ST4) PBi resist complement-mediated killing by binding of FHL-1. To identify the primary ligands of FHL-1 four CspA orthologs from <it>B. garinii </it>ST4 PBi were cloned and tested for binding to human CFH and FHL-1. Orthologs BGA66 and BGA71 were found to be able to bind both complement regulators but with different intensities. In addition, all CspA orthologs were tested for binding to mammalian and avian CFH. Distinct orthologs were able to bind to CFH of different animal origins.</p> <p>Conclusions</p> <p><it>B. garinii </it>ST4 PBi is able to evade complement killing and it can bind FHL-1 to membrane expressed proteins. Recombinant proteins BGA66 can bind FHL-1 and human CFH, while BGA71 can bind only FHL-1. All recombinant CspA orthologs from <it>B. garinii </it>ST4 PBi can bind CFH from different animal origins. This partly explains the wide variety of animals that can be infected by <it>B. garinii</it>.</p

An information-theoretic approach to the analysis of location and colocation patterns

The study of location and colocation of economic activities lies at the heart of economic geography and related disciplines, but the indices used to quantify these patterns are often defined ad hoc and lack a clear statistical foundation. We propose a statistical framework to quantify location and colocation associations of economic activities using information-theoretic measures. We relate the resulting measures to existing measures of revealed comparative advantage, localization, specialization, and coagglomeration and show how different measures derive from the same general framework. To support the use of these measures in hypothesis testing and statistical inference, we develop a Bayesian estimation approach to provide measures of uncertainty and statistical significance of the estimated quantities. We illustrate this framework in an application to an analysis of location and colocation patterns of occupations in US cities

Extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE) among travellers to Africa : destination-specific data pooled from three European prospective studies

Abstract Background One third of travellers to low- and middle-income regions of the tropics and subtropics become colonized by extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE). The risk varies by destination and, for each traveller, may be substantially further increased by travellers’ diarrhoea (TD) and antibiotic use. Despite the risk of TD in Africa, ESBL-PE acquisition rates in all studies are lower there than in Asia. Africa has become increasingly popular as a destination for international travellers, yet minimal data are available from the continent’s subregions and countries. Methods We analysed subregion- and country-specific data on carriage and risk factors for ESBL-PE colonization pooled from three prospective studies conducted between 2009 and 2013 among Finnish and Dutch travellers. The data were subjected to multivariable analysis of risk factors. In addition, we compared our data to two recent large investigations reporting data by subregion and country. Results Our joint analysis comprised data on 396 travellers. The ESBL-PE colonization rate was highest in Northern Africa, followed by Middle and Eastern Africa, and lowest in Southern and Western Africa. Of individual countries with more than 15 visitors, the highest rates were seen for Egypt (12/17; 70.6%), Ghana (6/23; 26.1%), and Tanzania (14/81; 17.3%); the rates among travellers to Egypt were comparable to those reported in South and Southeast Asia. In a pooled multivariable analysis, travel destination, age, overnight hospitalisation abroad, TD, and use of fluoroquinolones were independently associated with increased ESBL-PE colonization rates. Conlusions Even in areas with relatively low risk of colonization, antimicrobials clearly predispose to colonization with ESBL-PE. Travellers to Africa should be cautioned against unnecessary use of antibiotics

Extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE) among travellers to Africa : destination-specific data pooled from three European prospective studies

Background: One third of travellers to low- and middle-income regions of the tropics and subtropics become colonized by extended-spectrum beta-lactamase-producing Enterobacteriaceae (ESBL-PE). The risk varies by destination and, for each traveller, may be substantially further increased by travellers' diarrhoea (TD) and antibiotic use. Despite the risk of TD in Africa, ESBL-PE acquisition rates in all studies are lower there than in Asia. Africa has become increasingly popular as a destination for international travellers, yet minimal data are available from the continent's subregions and countries. Methods: We analysed subregion- and country-specific data on carriage and risk factors for ESBL-PE colonization pooled from three prospective studies conducted between 2009 and 2013 among Finnish and Dutch travellers. The data were subjected to multivariable analysis of risk factors. In addition, we compared our data to two recent large investigations reporting data by subregion and country. Results: Our joint analysis comprised data on 396 travellers. The ESBL-PE colonization rate was highest in Northern Africa, followed by Middle and Eastern Africa, and lowest in Southern and Western Africa. Of individual countries with more than 15 visitors, the highest rates were seen for Egypt (12/17; 70.6%), Ghana (6/23; 26.1%), and Tanzania (14/81; 17.3%); the rates among travellers to Egypt were comparable to those reported in South and Southeast Asia. In a pooled multivariable analysis, travel destination, age, overnight hospitalisation abroad, TD, and use of fluoroquinolones were independently associated with increased ESBL-PE colonization rates. Conlusions: Even in areas with relatively low risk of colonization, antimicrobials clearly predispose to colonization with ESBL-PE. Travellers to Africa should be cautioned against unnecessary use of antibiotics.Peer reviewe

Monitoring recently acquired HIV infections in Amsterdam, The Netherlands:The attribution of test locations

Background:  Surveillance of recent HIV infections (RHI) using an avidity assay has been implemented at Dutch sexual health centres (SHC) since 2014, but data on RHI diagnosed at other test locations is lacking. Setting:  Implementation of the avidity assay in HIV treatment clinics for the purpose of studying RHI among HIV patients tested at different test locations. Methods: We retrospectively tested leftover specimens from newly diagnosed HIV patients in care in 2013–2015 in Amsterdam. Avidity Index (AI) values ≤0.80 indicated recent infection (acquired ≤6 months prior to diagnosis), and AI > 0.80 indicated established infection (acquired >6 months prior to diagnosis). An algorithm for RHI was applied to correct for false recency. Recency based on this algorithm was compared with recency based on epidemiological data only. Multivariable logistic regression analysis was used to identify factors associated with RHI among men who have sex with men (MSM).Results: We tested 447 specimens with avidity; 72% from MSM. Proportions of RHI were 20% among MSM and 10% among heterosexuals. SHC showed highest proportions of RHI (27%), followed by GPs (15%), hospitals (5%), and other/unknown locations (11%) (p < 0.001). Test location was the only factor associated with RHI among MSM. A higher proportion of RHI was found based on epidemiological data compared to avidity testing combined with the RHI algorithm. Conclusion:  SHC identify more RHI infections compared to other test locations, as they serve high-risk populations and offer frequent HIV testing. Using avidity-testing for surveillance purposes may help targeting prevention programs, but the assay lacks robustness and its added value may decline with improved, repeat HIV testing and data collection

Serviços de verificação de óbitos

BackgroundNeisseria gonorrhoeae antibiotic resistance surveillance is important to maintain adequate treatment. We analysed 2007-15 data from the Gonococcal Resistance to Antimicrobials Surveillance (GRAS), which currently includes 19 of 25 sexually transmitted infection (STI) centres in the Netherlands. Methods: From each patient with a gonorrhoea culture, the minimum inhibitory concentration (MIC) for several antibiotics was determined. Time trends were assessed by geometric means and linear regression of logarithmic MIC. Determinants for decreased susceptibility to ceftriaxone (MIC > 0.032 mg/L) and resistance to cefotaxime (MIC > 0.125 mg/L) and azithromycin (MIC > 0.5 mg/L) were assessed using stratified logistic regression. Results: 11,768 isolates were analysed. No ceftriaxone resistance was found. In 2015, 27 of 1,425 isolates (1.9%) were resistant to cefotaxime and 176 of 1,623 (10.9%) to azithromycin. Ceftriaxone susceptibility showed no trend (p = 0.96) during the study period, but cefotaxime MIC decreased (p < 0.0001) and azithromycin MIC increased (p < 0.0001) significantly. Concerning ceftriaxone, isolates of men who have sex with men (MSM) from 2013 (p = 0.0005) and 2014 (p = 0.0004) were significantly associated with decreased susceptibility. Significant determinants for cefotaxime resistance were having ≥ 6 partners for women (p = 0.0006). For azithromycin,isolates from MSM collected in 2012 (p = 0.0035), 2013 (p = 0.012), and 2014 (p = 0.013), or from non-Dutch (p < 0.0001) or older (≥ 35 years; p = 0.01) MSM were significantly associated with susceptibility. Resistance in heterosexual men was significantly associated with being ≥ 25 years-old (p = 0.0049) or having 3-5 partners (p = 0.01). Conclusions: No ceftriaxone resistance was found, but azithromycin MIC increased in 2007-15. Resistance determinants could help with focused intervention strategies