Wustite as a new precursor of industrial ammonia synthesis catalysts

Contradictory results about the best oxidic precursor of Fe ammonia synthesis catalyst prompted the present comparative investigation on wustite- and magnetite-based catalysts. Many physical (density, porous texture, crystalline phases, reduction rate, metal surface, abrasion loss) and catalytic (kinetic constants, thermoresistancy) properties have been determined on both catalysts. The wustite-based catalyst proved to be much more active, especially at lower temperatures, approaching the performances of Ru/C catalyst, except at high conversion. Possible reasons for such a behavior of the wustite-based catalyst are discussed, suggesting that a reconsideration of the present consolidated knowledge on Fe ammonia synthesis catalyst might be convenien

Home and Work Physical Activity Environments: Associations with Cardiorespiratory Fitness and Physical Activity Level in French Women

The influence of the physical activity environment in the home and at work on cardiorespiratory fitness (CRF) and objectively-measured physical activity has not been extensively studied. We recruited 147 women with a (mean ± SD) age of 54 ± 7 years and without evidence of chronic disease. The physical activity environment was assessed by self-report (Assessing Levels of PHysical Activity or ALPHA questionnaire), CRF using a submaximal step test, usual physical activity using combined heart rate and accelerometry, as well as by a validated questionnaire (Recent Physical Activity Questionnaire). Summary scores of the home environment and the work environment derived from the ALPHA questionnaire were positively correlated with CRF after adjustment for age ($r$ = 0.18, $p$ = 0.03 and $r$ = 0.28, $p$ < 0.01, respectively). Women owning a bicycle or having a garden (which may prompt physical activity) had higher CRF; those with a bicycle at home also had a higher physical activity energy expenditure. Similarly, women who had access to fitness equipment at work had higher CRF. In conclusion, these results provide new insights into potential environmental influences on physical capacity and physical activity that could inform the design of physical activity promotion strategies.European Union (Integrated Project LSHM-CT-2006-037197 in the Framework Programme 6 of the European Community), Medical Research Council (Grant ID: MC_UU_12015/3

Pd-Fe/SiO2 Catalysts in the Hydrogenation of 2,4-Dinitrotoluene

Pd-Fe/SiO2 bimetallic catalysts with a constant amount of Pd and a different Fe/Pd ratio were prepared by sequential wet mpregnation and the hydrogenation of 2,4-dinitrotoluene was arried out at 25'C in a batch reactor. The presence of Fe nhances the Pd catalytic activity. The formation of a disperse Pd-Fe alloy was evidenced through X-ray powder diffraction nd is consistent with the data observed by FTIR analysis, TPR, nd chemisorption features. The increase of the Fe total conten f the catalysts results in the increase of the dispersion of the metallic phase and in the presence of partially oxidized Fe pecies. FTIR analysis shows that nitrocompounds chemisorb mainly on the support rather than on the metal surface. It is uggested that the Pd-Fe alloy formation is responsible for the ncrease of the catalytic activity because of a cooperative effect of Fe in the hydrogen transfer step

SARS-CoV-2 transmission risk from asymptomatic carriers: Results from a mass screening programme in Luxembourg.

BACKGROUND: To accompany the lifting of COVID-19 lockdown measures, Luxembourg implemented a mass screening (MS) programme. The first phase coincided with an early summer epidemic wave in 2020. METHODS: rRT-PCR-based screening for SARS-CoV-2 was performed by pooling of samples. The infrastructure allowed the testing of the entire resident and cross-border worker populations. The strategy relied on social connectivity within different activity sectors. Invitation frequencies were tactically increased in sectors and regions with higher prevalence. The results were analysed alongside contact tracing data. FINDINGS: The voluntary programme covered 49% of the resident and 22% of the cross-border worker populations. It identified 850 index cases with an additional 249 cases from contact tracing. Over-representation was observed in the services, hospitality and construction sectors alongside regional differences. Asymptomatic cases had a significant but lower secondary attack rate when compared to symptomatic individuals. Based on simulations using an agent-based SEIR model, the total number of expected cases would have been 42·9% (90% CI [-0·3, 96·7]) higher without MS. Mandatory participation would have resulted in a further difference of 39·7% [19·6, 59·2]. INTERPRETATION: Strategic and tactical MS allows the suppression of epidemic dynamics. Asymptomatic carriers represent a significant risk for transmission. Containment of future outbreaks will depend on early testing in sectors and regions. Higher participation rates must be assured through targeted incentivisation and recurrent invitation. FUNDING: This project was funded by the Luxembourg Ministries of Higher Education and Research, and Health

Raleio químico: balanço de carboidratos na cultura da macieira.

Abusca constante do agricultor é sempre por maior lucratividade na sua atividade. Essa lucratividade pode ser alcançada aumentando a produtividade, melhorando a qualidade da produção e, melhor ainda, através de ambas. Nos sistemas de economia globalizada da atualidade, onde a competitividade está sempre presente, a busca por maior produtividade deve sempre estar associada à alta qualidade. O raleio se insere neste contexto como uma das práticas culturais mais importantes, com influência direta na produtividade e na qualidade dos frutos (Camilo e Pereira, 2006). O raleio é comercialmente realizado a fim de maximizar o valor das culturas por meio da otimização do tamanho dos frutos, a coloração, a forma e a qualidade dos frutos destinados a comercialização, bem como promover o retorno da floração e reduzir o vigor da parte aérea das plantas (Byers, 2003).bitstream/item/200832/1/13850-2012-p.24.pd