External validation of risk prediction models for incident colorectal cancer using UK Biobank.

BACKGROUND: This study aimed to compare and externally validate risk scores developed to predict incident colorectal cancer (CRC) that include variables routinely available or easily obtainable via self-completed questionnaire. METHODS: External validation of fourteen risk models from a previous systematic review in 373 112 men and women within the UK Biobank cohort with 5-year follow-up, no prior history of CRC and data for incidence of CRC through linkage to national cancer registries. RESULTS: There were 1719 (0.46%) cases of incident CRC. The performance of the risk models varied substantially. In men, the QCancer10 model and models by Tao, Driver and Ma all had an area under the receiver operating characteristic curve (AUC) between 0.67 and 0.70. Discrimination was lower in women: the QCancer10, Wells, Tao, Guesmi and Ma models were the best performing with AUCs between 0.63 and 0.66. Assessment of calibration was possible for six models in men and women. All would require country-specific recalibration if estimates of absolute risks were to be given to individuals. CONCLUSIONS: Several risk models based on easily obtainable data have relatively good discrimination in a UK population. Modelling studies are now required to estimate the potential health benefits and cost-effectiveness of implementing stratified risk-based CRC screening

Monitoring and Evaluation of Public Agricultural Research Organization: Impact oriented monitoring approach

This study uses impact oriented monitoring (IOM) methodology recently proposed by Guinea et al. (2015) to identify and assess the socio-economic impact of public research organizations through case studies. IOM techniques overcome the most relevant limitations associated to mainstream research impact assessment (RIA). The IOM approach has been extended to a consideration of the multidimensional impact produced by the agricultural research and development. In contrast to previous studies, multi-criteria decision techniques based on ELECTRE III method are applied to derive global picture of impact. The methodology is expected to provide the Institute of Agro-food Research and Technology (IRTA) with useful information on how the research projects in the area of agro-food sector are generating impacts. Such analysis would support monitoring the impacts of agricultural research and assist in better targeting adequate research policy planning and project management strategies. The relevance of using new RIA approach can be evidenced by its applicability to other case studies and also its potential to be implemented in other agricultural research institutions in different countries. The use of refined methods has thus important implications. Acknowledgement : The authors gratefully acknowledge the financial support from the Institute for Food and Agricultural Research and Technology (IRTA)

La eficiencia productiva de la agricultura ecológica: el caso del sector de la uva en Cataluña

Knowledge about productivity and efficiency differences between conventional and organic farms has important implications for the evaluation of the economic viability of these two agricultural practices. The main purpose of this study was to compare the efficiency ratings of organic and conventional grape farms in Catalonia. To do so, we fit a stochastic production frontier to cross sectional, farm-level data collected from a sample of 141 Catalan farms that specialize in grape growing. Results show that organic farmers, on average, are more efficient than their conventional counterparts (efficiency ratings are on the order of 0.80 and 0.64, respectively). Apart from adoption of organic practices, experience is also found to improve technical efficiency. Conversely, technical efficiency tends to decrease with the relevance of unpaid family labor, farm location in less favored areas, and farmers’ strong environmental preservation preferences.Conocer las diferencias de productividad y eficiencia entre la agricultura convencional y la ecológica tiene implicaciones importantes para la evaluación de la viabilidad económica de estas dos prácticas agrícolas. El principal objetivo de este estudio fue comparar la eficiencia técnica de las explotaciones de uva ecológicas y convencionales en Cataluña. Para ello utilizamos el modelo de la frontera de producción estocástica. El análisis se basó en datos de corte transversal de una muestra de 141 explotaciones catalanas especializadas en la producción de uva. Los agricultores ecológicos fueron, de promedio, técnicamente más eficientes que los convencionales (los ratios de eficiencia fueron 0,80 y 0,64, respectivamente). Además de la adopción de técnicas ecológicas, la experiencia también incrementa la eficiencia técnica. En cambio, las explotaciones con una mayor proporción de trabajo no remunerado, que se encuentran en una zona desfavorecida y/o que tienden a tener fuertes preferencias por preservar el medio ambiente, son generalmente menos eficientes

Does the S-H Bond Always Break after Adsorption of an Alkylthiol on Au(111)?

International audienceThe reaction mechanism for the formation of alkyl thiol self-assembled monolayers (SAM) on Au(111) is still not clearly understood. Especially, the role of defects on the chemisorption process is an important goal to be addressed. In this work, different minimum energy reaction paths for R−SH dissociation of thiols (with long and short chains and dithiol species) adsorbed on gold adatom are calculated by using periodic density functional theory (DFT). Our results show a lower energy barrier for the RS−H bond dissociation when two thiols are adsorbed per adatom. In addition, in contrast with the formation of an adatom at the Au(111) which has been shown to depend on the alkyl chain length, the activation energy of the RS−H bond dissociation of thiols adsorbed on an adatom was shown to be independent of the alkyl chain length. The presented results and derived hypothesis support the model that thiols with long alkyl chain thiols mainly adsorb molecularly on Au(111), while for short alkyl chain thiols the S−H bond breaks. This result is explained by the fact that short-chain thiols have lower interchain interaction energies and are thus more mobile compared to the long alkyl chain thiols on the Au(111) surface. This feature enables the short chains to reach adequate geometries, driven by entropy, which could deform the Au(111) more drastically and probably pull Au atoms out from surface to form adatoms. With these results a new mechanism is proposed for the formation of alkyl chain thiols on Au(111)

Crossover among structural motifs in Pd–Au nanoalloys

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A Carrier-Based PWM Techniques Applied to a Three-level Four-Leg Inverter for Use as a Shunt Active Power Filter

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