Evaluation of the variability of compressive strength parallel to the fibers of hardwood species

Wood has several advantages as structural material. For this use to be applied in a safe way, it is necessary to know the statistical behavior of the mechanical properties. Some works and normative codes, such as the “Brazilian timber standard” (as well as its review project), accepts a normal distribution model for determining the characteristic value of compressive strength parallel to wood fiber, with the adoption of a coefficient of variation for this property equal to 18 %. This work evaluates the distribution model of compressive strength parallel to the fibers, as well as the coefficient of variation of this property. Tests and statistical treatment were performed in compression parallel to the fibers for 7 species of hardwood commonly found in Brazil. It was observed that the compressive strength of wood actually follows a normal distribution, and the adoption of an average coefficient of variation equal to 18 % is acceptable and in favor of safety.&nbsp

Ilex paraguariensis extracts extend the lifespan of Drosophila melanogaster fed a high-fat diet

Studies have suggested that total energy intake and diet composition affect lifespan and ageing. A high-fat diet induces oxidative stress and affects the development of diseases. In contrast, antioxidants are capable of reducing its harmful effects. Yerba mate beverages are an important source of antioxidants, but there is scarce knowledge about their effects on suppressing fat accumulation. Here, we investigated the compounds present in yerba mate extracts and assessed their effects on Drosophila melanogaster given a high cholesterol diet. LS-ESI-MS analysis showed the presence of matesaponins, phenolic compounds and methylxanthines in all of the examined extracts. In Drosophila, under extract treatment conditions, the mean lifespan was significantly extended from 38 to 43 days, there was an increase in the ability to support induced stress and decrease in lipid peroxidation products. Moreover, yerba mate extracts recovered the glutathione S-transferases (GST) activity and reduced the cholesterol level. Taken together, our results support that extracts can extend lifespan by reducing the detrimental effect of a high-fat diet in D. melanogaster, and this outcome can be associated with the compound content in the extracts. This study improves the understanding of natural interventions that reduce stress-induced oxidative damage, which is fundamental in promoting healthy ageing

Study of Leading Hadrons in Gluon and Quark Fragmentation

The study of quark jets in e+e- reactions at LEP has demonstrated that the hadronisation process is reproduced well by the Lund string model. However, our understanding of gluon fragmentation is less complete. In this study enriched quark and gluon jet samples of different purities are selected in three-jet events from hadronic decays of the Z collected by the DELPHI experiment in the LEP runs during 1994 and 1995. The leading systems of the two kinds of jets are defined by requiring a rapidity gap and their sum of charges is studied. An excess of leading systems with total charge zero is found for gluon jets in all cases, when compared to Monte Carlo Simulations with JETSET (with and without Bose-Einstein correlations included) and ARIADNE. The corresponding leading systems of quark jets do not exhibit such an excess. The influence of the gap size and of the gluon purity on the effect is studied and a concentration of the excess of neutral leading systems at low invariant masses (<~ 2 GeV/c^2) is observed, indicating that gluon jets might have an additional hitherto undetected fragmentation mode via a two-gluon system. This could be an indication of a possible production of gluonic states as predicted by QCD.Comment: 19 pages, 6 figures, Accepted by Phys. Lett.

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Quality control of B-lines analysis in stress Echo 2020

Background The effectiveness trial “Stress echo (SE) 2020” evaluates novel applications of SE in and beyond coronary artery disease. The core protocol also includes 4-site simplified scan of B-lines by lung ultrasound, useful to assess pulmonary congestion. Purpose To provide web-based upstream quality control and harmonization of B-lines reading criteria. Methods 60 readers (all previously accredited for regional wall motion, 53 B-lines naive) from 52 centers of 16 countries of SE 2020 network read a set of 20 lung ultrasound video-clips selected by the Pisa lab serving as reference standard, after taking an obligatory web-based learning 2-h module ( http://se2020.altervista.org ). Each test clip was scored for B-lines from 0 (black lung, A-lines, no B-lines) to 10 (white lung, coalescing B-lines). The diagnostic gold standard was the concordant assessment of two experienced readers of the Pisa lab. The answer of the reader was considered correct if concordant with reference standard reading ±1 (for instance, reference standard reading of 5 B-lines; correct answer 4, 5, or 6). The a priori determined pass threshold was 18/20 (≥ 90%) with R value (intra-class correlation coefficient) between reference standard and recruiting center) > 0.90. Inter-observer agreement was assessed with intra-class correlation coefficient statistics. Results All 60 readers were successfully accredited: 26 (43%) on first, 24 (40%) on second, and 10 (17%) on third attempt. The average diagnostic accuracy of the 60 accredited readers was 95%, with R value of 0.95 compared to reference standard reading. The 53 B-lines naive scored similarly to the 7 B-lines expert on first attempt (90 versus 95%, p = NS). Compared to the step-1 of quality control for regional wall motion abnormalities, the mean reading time per attempt was shorter (17 ± 3 vs 29 ± 12 min, p < .01), the first attempt success rate was higher (43 vs 28%, p < 0.01), and the drop-out of readers smaller (0 vs 28%, p < .01). Conclusions Web-based learning is highly effective for teaching and harmonizing B-lines reading. Echocardiographers without previous experience with B-lines learn quickly.info:eu-repo/semantics/publishedVersio