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Microplastics (MPs) in soil affect plant–soil systems depending on their shape and polymer type. However, previous research has not yet considered the effects of degraded plastics, which are the plastic materials actually present in the environment.We selected eight MPs representing different shapes (fibres, films and foams) and polymer types, and exposed them to UV‐C degradation. Each MP was mixed with soil at a concentration of 0.4% (w/w). The phytometer Daucus carota grew in each pot. At harvest, soil properties and plant biomass were measured.Photodegradation altered MP physical and chemical properties, impacting plant–soil systems. MP degradation effects on plant and soil were observed with fibres and foams, but there were negligible effects with films. The latter could be explained by the polymer structure of films and manufacturer's additives, potentially delaying their degradation.Degraded fibres increased soil respiration more than their non‐degraded counterparts, as photodegradation increased the positive effects of fibres on soil water retention. The emergence of oxygenated groups during degradation may have increased the hydrophilicity of fibres, enhancing their ability to retain water. Degraded foams increased soil respiration, which could be related to the possible leaching of organic substances with lower partition coefficients, which may promote soil microbial activity.In contrast, degraded foams decreased soil aggregation, likely as degradation produced larger holes increasing their permeability. Also, the increase in hydrophilic molecules could have decreased soil particle cohesiveness. Degraded fibres and foams increased shoot and root mass as a result of MP effects on soil properties. Photodegraded MPs affected root traits, which could be linked to MP effects on soil water status and plant coping strategies.Synthesis and applications. Photodegradation can intensify the effects that microplastics (MPs) have on plant–soil systems, which would have frequently been underestimated had we only worked with pristine MPs. Plastic companies, agricultural practitioners and researchers should consider that plastics are being degraded as they enter the soil. Policies should promote practices to minimize MP accumulation in soils and ensure their proper disposal. [ABSTRACT FROM AUTHOR]

Copyright of Tesla Revista Científica is the property of Puerto Madero Editorial Academica and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Feedbacks between land carbon pools and climate provide one of the largest sources of uncertainty in our predictions of global climate (1,2). Estimates of the sensitivity of the terrestrial carbon budget to climate anomalies in the tropics and the identification of the mechanisms responsible for feedback effects remain uncertain (3,4). The Amazon basin stores a vast amount of carbon (5), and has experienced increasingly higher temperatures and more frequent floods and droughts over the past two decades (6). Here we report seasonal and annual carbon balances across the Amazon basin, based on carbon dioxide and carbon monoxide measurements for the anomalously dry and wet years 2010 and 2011, respectively. We find that the Amazon basin lost 0.48 ± 0.18 petagrams of carbon per year (Pg C [yr.sup.-1]) during the dry year but was carbon neutral (0.06 ± 0.1 Pg C [yr.sup.-1]) during the wet year. Taking into account carbon losses from fire by using carbon monoxide measurements, we derived the basin net biome exchange (that is, the carbon flux between the non-burned forest and the atmosphere) revealing that during the dry year, vegetation was carbon neutral. During the wet year, vegetation was a net carbon sink of 0.25 ± 0.14 Pg C [yr.sup.-1], which is roughly consistent with the mean long-term intact-forest biomass sink of 0.39 ± 0.10 Pg C [yr.sup.-1] previously estimated from forest censuses (7). Observations from Amazonian forest plots suggest the suppression of photosynthesis during drought as the primary cause for the 2010 sink neutralization. Overall, our results suggest that moisture has an important role in determining the Amazonian carbon balance. If the recent trend of increasing precipitation extremes persists (6), the Amazon may become an increasing carbon source as a result of both emissions from fires and the suppression of net biome exchange by drought., To observe the state, changes and climate sensitivity of the Amazon carbon pools we initiated a lower-troposphere greenhouse-gas sampling programme over the Amazon basin in 2010, measuring bi-weekly vertical profiles [...]

Intensity‐modulated radiation therapy is used worldwide to treat cancer patients. The objective of this treatment is to deliver a prescribed radiation dose to the tumor while sparing, as much as possible, all the healthy tissues, especially organs at risk (OAR). This means that the planning of a radiotherapy treatment should take into consideration conflicting objectives: to be able to spare as much as possible the OAR guaranteeing, at the same time, that the desired radiation is delivered to the volumes to treat. While the volumes to treat can be adequately irradiated from almost any set of directions, the radiation directions that are chosen have a determinant impact on the OAR. This means that those directions that provide an improved OAR sparing should be selected. The choice of radiation directions (beam angles) can thus be interpreted as being fundamentally determined by the OAR, with the radiation intensities associated with each of these directions being determined by the needed radiation to be delivered to the volumes to treat. In this work, we interpret the radiotherapy treatment planning problem as a bi‐level optimization problem. At the upper level, OAR control the choice of the beam angles, which are selected aiming at OAR sparing. At the lower level, the optimal radiation intensities are decided by the volumes to treat, considering the beam angle ensemble obtained at the upper level. The proposed bi‐level approach was tested using 10 clinical head‐and‐neck cancer cases already treated at the Portuguese Institute of Oncology in Coimbra. [ABSTRACT FROM AUTHOR]

Radiation therapy is a technology‐driven cancer treatment modality that has experienced significant advances over the last decades, due to multidisciplinary contributions that include engineering and computing. Recent technological developments allow the use of noncoplanar volumetric modulated arc therapy (VMAT), one of the most recent photon treatment techniques, in clinical practice. In this work, an automated noncoplanar arc trajectory optimization framework designed in two modular phases is presented. First, a noncoplanar beam angle optimization algorithm is used to obtain a set of noncoplanar irradiation directions. Then, anchored in these directions, an optimization strategy is proposed to compute an optimal arc trajectory. The computational experiments considered a pool of twelve difficult head‐and‐neck tumor cases. It was possible to observe that, for some of these cases, the optimized noncoplanar arc trajectories led to significant treatment planning quality improvements, when compared with coplanar VMAT treatment plans. Although these experiments were done in a research environment treatment planning software (matRad), the conclusions can be of interest for a clinical setting: automated procedures can simplify the current treatment workflow, produce high‐quality treatment plans, making better use of human resources and allowing for unbiased comparisons between different treatment techniques. [ABSTRACT FROM AUTHOR]

Tropical forests are recognized for their role in providing diverse ecosystem services (ESs), with carbon uptake the best recognized. The capacity of tropical forests to provide ESs is strongly linked to their enormous biodiversity. However, causal relationships between biodiversity and ESs are poorly understood. This may be because biodiversity is often translated into species richness. Here, we argue that focusing on multiple attributes of biodiversity—structure, composition, and function—will make relationships between biodiversity and ESs clearer. In this review, we discuss the ecological processes behind ESs from tropical humid and subhumid forests of South America. Our main goal is to understand the links between the ESs and those three biodiversity attributes. While supporting and regulating services relate more closely to forest structure and function, provisioning services relate more closely to forest composition and function, and cultural services are more related to structure and composition attributes. In this sense, ESs from subhumid forests (savannas) differ from those provided by the Amazon Forest, although both ecosystems are recognized as harboring tremendous biodiversity. Given this, if anthropogenic drivers of change promote a shift in the Amazon Forest toward savanna—the savannization hypothesis—the types of services provided will change, especially climate regulating services. This review emphasizes the importance of deeply understanding ecosystem structure, composition, and function to better understand the services ecosystems provide. Understanding that anthropogenic impacts on biodiversity occur through these three main attributes, it becomes easier to anticipate how humans will impact ESs. Key Points: Tropical forests' biodiversity promotes diverse ecosystem services (ESs), but relationships between biodiversity and ESs are not obviousDifferent ES types are related to different attributes of biodiversity: structure, composition, and functionsSavannization of Amazonia could impact the types of ESs provided by rain forests, particularly climate regulating services [ABSTRACT FROM AUTHOR]

Due to the great worldwide increase in pineapple production, countries like Brazil and India have problems regarding the correct disposal of residues from the production of this fruit. One of the possibilities is the reuse of these residues in the form of fibers in cementitious materials, as is the case with mortars. As a result, the objective of this work is to evaluate the application of pineapple fibers in mortars in the proportion of 1: 4 (cement: sand) with addition of fiber treated in NaOH in the proportion of 3 and 6%. The properties of mechanical resistance, water absorption, mass density and adhesion were evaluated, aiming to apply the mortar in coatings of rural environments. The results indicate that the fibers reduced the mortar density and increased the mechanical strength. However, there was a reduction in adherence, especially with the use of 6% fiber, in addition to an increase in water absorption. Based on the results, it is concluded that it is feasible to use 3% of pineapple fiber for the production of coating mortars in rural environments because the results obtained in the investigation are compatible with this application and with the established normative limits. [ABSTRACT FROM AUTHOR]

Copyright of HOLOS is the property of Instituto Federal do Rio Grande do norte - IFRN and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Southeast Brazil has great economic importance for Brazil and is highly vulnerable to extreme events like floods and droughts. Studies have shown an increase of temperature in this region. Using a new detection and attribution framework (Ribes et al., 2017, https://doi.org/10.1007/s00382-016-3079-6) and Coupled Model Intercomparison Project Phase 5 models, this change is found to be largely due to greenhouse gases. We estimate that greenhouse gases contribute a warming of 0.95 to 1.5 °C to the observed warming trend of 1.1 °C between 1955 and 2004. Temperature changes from natural and nongreenhouse gas anthropogenic forcing are estimated to be small over this period. Results are robust using different time windows. Using the Community Earth System Model ensembles to evaluate the impacts of internal variability, observational and model error shows that most uncertainty arises from model error. Plain Language Summary: Southeast Brazil has great economic importance for Brazil and is highly vulnerable to extreme events like floods, droughts, and heat waves. Many studies link those kind of events with an increase in temperature due to climate change, largely caused by increasing atmospheric concentrations of greenhouse gases. This study tested whether or not human‐induced climate change is responsible for the observed increase in temperature in Southeast Brazil. The observed 1.1 °C per 50‐year trend is largely due to increasing greenhouse gases, which means that they have a significant role in observed changes in Southeast Brazilian temperatures. Key Points: New detection and attribution method is used to attribute temperature trends for Southeast BrazilGreenhouse gases are the dominant driver of observed temperature trendsModel uncertainty plays an important role in this study [ABSTRACT FROM AUTHOR]

Here we present a numerical analysis and the optimization of a multi-pump discrete Raman amplification system based on the use of a Tellurite optical fiber as the gain media. By using previously reported optimization techniques we were able to exploit the high Raman gain of Tellurite optical fibers and its multipeak spectrum to achieve amplification over an amplification band from 1520 to 1600 nm. Average gains around 10 dB with ripples in the region of 3 dB were achieved using only 3 pumps with less than 800 mW each. Optimized systems were obtained for different lengths of fiber showing that discrete Raman amplifiers based on tellurite fibers with lengths as short as 100 meters can provide high gains and low ripples in a broad wavelength band. Lower cost systems using only 2 pumps were also analyzed in this study providing 5.8 dB of gain with only 2.4 dB of ripple for an 80 nm signal bandwidth. [ABSTRACT FROM AUTHOR]