Estiolamento, incisão na base da estaca e uso do ácido indolbutírico na propagação da caramboleira por estacas lenhosas.

Objetivou-se, neste trabalho, avaliar o efeito do estiolamento, da incisão na base da estaca e do tratamento com ácidoindolbutírico (AIB) no enraizamento de estacas lenhosas de caramboleira. As estacas foram padronizadas com um par de folhasinteiras e 12 cm de comprimento

Diferentes substratos na produção de porta-enxertos de caramboleira.

Objetivou-se com o presente estudo verificar a influência de diferentes substratos na produção de porta-enxertos de caramboleira. As sementes foram extraídas de frutos maduros de carambola cultívar Malásía, lavadas em água corrente e semeadas em bandejas de poliestireno (72 células, capacidade de 120 cm3/célula), contendo os seguintes substratos: vermículita, Plantmax, Rendmax, terra de barranco, areia e terra + areia (1:1, 2:1 e 1:2 v/v). Em seguída, as bandejas foram colocadas em ambiente coberto por sombrite com 50 % de lurninosidade, efetuando-se regas manuais diárias. Após 130 dias da semeadura, foram coletados os seguintes dados biométricos: porcentagem de plantas vivas, altura das plântulas, comprimento das raízes e número de folhas. Concluiu-se que a mistura terra + areia (1:1 v/v) foi mais eficiente na germinação de sementes e formação inicial de porta-enxertos de caramboleira

STUDIO DEL COMPORTAMENTO MECCANICO DI UNA LEGA FeMo A GRANO ULTRAFINE OTTENUTA PER MACINAZIONE DI POLVERI E SINTERIZZAZIONE MEDIANTE SPS

Mediante macinazione ad alta energia e successiva sinterizzazione mediante tecnica SPS (Spark Plasma Sintering)è stata prodotta una lega FeMo a grano cristallino ultra fine (100-500 nm) con densità superiore al 99%della densità teorica. L’aggiunta di nanoparticelle di SiO2 ha consentito di limitare la crescita dei cristallitidurante la sinterizzazione, mantenendo così il grano ultrafine ottenuto con la macinazione.Il comportamento meccanico della lega è stato studiato con prove di trazione. La presenza di una distribuzionebimodale della dimensione dei cristalliti ha un effetto positivo sulla duttilità, attivando meccanismi di deformazioneresponsabili di un certo incrudimento. Sono state condotte anche prove FIMEC (Flat-top CylinderIndenter for Mechanical Characterization), i cui risultati trovano una corrispondenza, nei valori del carico disnervamento, molto buona con quelli delle prove di trazione. Queste prove sono state condotte anche a varietemperature, per individuare la Temperatura di Transizione Duttile-Fragile, che si è riscontrato diminuire conla dimensione dei cristalliti

Association between long-term exposure to low ambient PM2.5 and cardiovascular hospital admissions: A UK Biobank study

Introduction: A causal link between air pollution exposure and cardiovascular events has been suggested. However fewer studies have investigated the shape of the associations at low levels of air pollution and identified the most important temporal window of exposure. Here we assessed long-term associations between particulate matter 40) from the UK Biobank cohort, we investigated the associations between 1-year, 3-year and 5-year time-varying averages of PM2.5 and incidence of major adverse cardiovascular events (MACE), myocardial infarction (MI), heart failure, atrial fibrillation and flutter and cardiac arrest. We also investigated outcome subtypes for MI and stroke. Events were defined as hospital inpatient admissions. We fitted Cox proportional hazard regression models applying extensive control for confounding at both individual and area level. Finally, we assessed the shape of the exposure–response functions to assess effects at low levels of exposure. Results: We analysed data from 377,736 study participants after exclusion of prevalent subjects. The average follow-up (2006–2021) was 12.9 years. We detected 19,353 cases of MACE, 6,562 of acute MI, 6,278 of heart failure, 1,258 for atrial fibrillation and flutter, and 16,327 for cardiac arrest. Using a 5-year exposure window, we detected positive associations (for 5 μg/m3 increase in PM2.5) for 5-point MACE of [1.12 (95 %CI: 1.00–1.26)], heart failure [1.22 (1.00–1.50)] and cardiac arrest [1.16 (1.03–1.31)]. We did not find any association with acute MI, while non-ST-elevation MI was associated with the 1-year exposure window [1.52 (1.12–2.07)]. The assessment of the shape of the exposure–response relationships suggested that risk is approximately linear for most of the outcomes. Conclusions: We found positive associations between long-term exposure to PM2.5 and multiple cardiovascular outcomes for different exposure windows. The cardiovascular risk tends to rise even at exposure concentrations below 12–15 μg/m3, indicating high risk below UK national and international thresholds.Environment International, 192, art. no. 109011; 2024journal articl

High resolution mapping of nitrogen dioxide and particulate matter in Great Britain (2003-2021) with multi-stage data reconstruction and ensemble machine learning methods

In this contribution, we applied a multi-stage machine learning (ML) framework to map daily values of nitrogen dioxide (NO2) and particulate matter (PM10 and PM2.5) at a 1 km2 resolution over Great Britain for the period 2003-2021. The process combined ground monitoring observations, satellite-derived products, climate reanalyses and chemical transport model datasets, and traffic and land-use data. Each feature was harmonized to 1 km resolution and extracted at monitoring sites. Models used single and ensemble-based algorithms featuring random forests (RF), extreme gradient boosting (XGB), light gradient boosting machine (LGBM), as well as lasso and ridge regression. The various stages focused on augmenting PM2.5 using co-occurring PM10 values, gap-filling aerosol optical depth and columnar NO2 data obtained from satellite instruments, and finally the training of an ensemble model and the prediction of daily values across the whole geographical domain (2003-2021). Results show a good ensemble model performance, calculated through a ten-fold monitor-based cross-validation procedure, with an average R2 of 0.690 (range 0.611-0.792) for NO2, 0.704 (0.609-0.786) for PM10, and 0.802 (0.746-0.888) for PM2.5. Reconstructed pollution levels decreased markedly within the study period, with a stronger reduction in the latter eight years. The pollutants exhibited different spatial patterns, while NO2 rose in close proximity to high-traffic areas, PM demonstrated variation at a larger scale. The resulting 1 km2 spatially resolved daily datasets allow for linkage with health data across Great Britain over nearly two decades, thus contributing to extensive, extended, and detailed research on the long-and short-term health effects of air pollution

X-ray Microtomography for Investigating Pore Space and Its Relation to Water Retention and Conduction in Highly Weathered Soils.

Abstract: Soil structure controls soil hydraulic properties and is linked to soil aggregation processes. The aggregation processes of Oxisols are controlled mainly by clay mineralogy and biological activity. Computed microtomography (µCT) may be a tool for improving the knowledge of the hydraulic properties of these soils. Thus, this study brings an advance in the use of 3D image analysis to better comprehend the water behavior in tropical soils. In this work, three Oxisols were studied with the objective to (i) characterize the soil water retention curve (SWRC), the corresponding pore size frequency, and the saturated hydraulic conductivity (Ksat); (ii) use µCT to obtain, based on 3D images of soil structure and pore size distribution; and (iii) correlating parameters from SWRCs, Ksat, and µCT with other physical-hydric, chemical, and mineralogical attributes. Rhodic Haplustox—P1, Anionic Acrustox—P2, and Typic Hapludox—P3 were the three studied Oxisols. The differences among the SWRCs were related to the microgranular and block type’s structure morphology, which modified the soil pore space. The pore size frequency was calculated from SWRCs for pores with diameters of 87 ± 2 µm in P1, 134 ± 11µm in P2, and 175 ± 18 µm in P3. Pore size distribution from µCT was determined for the range of 20–100 µm, mainly with the highest percentages: 12 ± 1.09% for P1 and 12 ± 1.4% for P2. Pore connectivity was assessed from images by calculating Euler Numbers (EN), with the differences related to the biggest pore (ENbigpore): P1 (−44,223 ± 10,096) and P2 (−44,621 ± 12,573) showed more connected pores (ENbigpore) in comparison to P3 (−11,597 ± 6935). The parameter ENbigpore was decisive in understanding the water retention and conduction processes of the studied soils. The better-connected pore space increased Ksat in P1 (220 ± 0.05 mm h−1 ) and P2 (189 ± 0.1 mm h−1 ) in comparison to P3 (20 ± 0.3 mm h−1 ) and modified the shape of SWRCs

Reconstructing individual-level exposures in cohort analyses of environmental risks: an example with the UK Biobank.

Recent developments in linkage procedures and exposure modelling offer great prospects for cohort analyses on the health risks of environmental factors. However, assigning individual-level exposures to large population-based cohorts poses methodological and practical problems. In this contribution, we illustrate a linkage framework to reconstruct environmental exposures for individual-level epidemiological analyses, discussing methodological and practical issues such as residential mobility and privacy concerns. The framework outlined here requires the availability of individual residential histories with related time periods, as well as high-resolution spatio-temporal maps of environmental exposures. The linkage process is carried out in three steps: (1) spatial alignment of the exposure maps and residential locations to extract address-specific exposure series; (2) reconstruction of individual-level exposure histories accounting for residential changes during the follow-up; (3) flexible definition of exposure summaries consistent with alternative research questions and epidemiological designs. The procedure is exemplified by the linkage and processing of daily averages of air pollution for the UK Biobank cohort using gridded spatio-temporal maps across Great Britain. This results in the extraction of exposure summaries suitable for epidemiological analyses of both short and long-term risk associations and, in general, for the investigation of temporal dependencies. The linkage framework presented here is generally applicable to multiple environmental stressors and can be extended beyond the reconstruction of residential exposures. IMPACT: This contribution describes a linkage framework to assign individual-level environmental exposures to population-based cohorts using high-resolution spatio-temporal exposure. The framework can be used to address current limitations of exposure assessment for the analysis of health risks associated with environmental stressors. The linkage of detailed exposure information at the individual level offers the opportunity to define flexible exposure summaries tailored to specific study designs and research questions. The application of the framework is exemplified by the linkage of fine particulate matter (PM2.5) exposures to the UK Biobank cohort

Association between long-term exposure to low ambient PM2.5 and cardiovascular hospital admissions: A UK Biobank study.

INTRODUCTION: A causal link between air pollution exposure and cardiovascular events has been suggested. However fewer studies have investigated the shape of the associations at low levels of air pollution and identified the most important temporal window of exposure. Here we assessed long-term associations between particulate matter  40) from the UK Biobank cohort, we investigated the associations between 1-year, 3-year and 5-year time-varying averages of PM2.5 and incidence of major adverse cardiovascular events (MACE), myocardial infarction (MI), heart failure, atrial fibrillation and flutter and cardiac arrest. We also investigated outcome subtypes for MI and stroke. Events were defined as hospital inpatient admissions. We fitted Cox proportional hazard regression models applying extensive control for confounding at both individual and area level. Finally, we assessed the shape of the exposure-response functions to assess effects at low levels of exposure. RESULTS: We analysed data from 377,736 study participants after exclusion of prevalent subjects. The average follow-up (2006-2021) was 12.9 years. We detected 19,353 cases of MACE, 6,562 of acute MI, 6,278 of heart failure, 1,258 for atrial fibrillation and flutter, and 16,327 for cardiac arrest. Using a 5-year exposure window, we detected positive associations (for 5 μg/m3 increase in PM2.5) for 5-point MACE of [1.12 (95 %CI: 1.00-1.26)], heart failure [1.22 (1.00-1.50)] and cardiac arrest [1.16 (1.03-1.31)]. We did not find any association with acute MI, while non-ST-elevation MI was associated with the 1-year exposure window [1.52 (1.12-2.07)]. The assessment of the shape of the exposure-response relationships suggested that risk is approximately linear for most of the outcomes. CONCLUSIONS: We found positive associations between long-term exposure to PM2.5 and multiple cardiovascular outcomes for different exposure windows. The cardiovascular risk tends to rise even at exposure concentrations below 12-15 μg/m3, indicating high risk below UK national and international thresholds