Speciation of gaseous oxidized mercury molecules relevant to atmospheric and combustion environments

Mercury is a pervasive and highly toxic environmental pollutant. Major anthropogenic sources of mercury emissions include artisanal gold mining, cement production, and combustion of coal. These sources release mostly gaseous elemental mercury (GEM), which upon entering the atmosphere can travel long distances before depositing to environmental waters and landforms. The deposition of GEM is relatively slow, but becomes greatly accelerated when GEM is converted to gaseous oxidized mercury (GOM) because the latter has significantly higher water solubility and lower volatility. Modeling GOM deposition requires the knowledge of its molecular identities, which are poorly known because ultra-trace (tens to hundreds part per quadrillion) level of GOM in the atmosphere makes its experimental detection and analysis a formidable task. It is here where computational methods can help address the GOM molecular identity problem. Accordingly, the two major goals of this work are to (a) develop a computationally inexpensive approach for assessing accurate thermochemistry of GOM species and (b) investigate ion-molecule reactions of GOM species in order to assist experimentalists in the development of a novel detection method. The first goal addresses the question of what are some of the molecular identities of GOM species that could be present in combustion and atmospheric environments. Ab initio and density functional theory calculations are used in combination with the methods of isodesmic and isogyric work reactions in order to calculate accurate heats of formation for GOM species that can form in reactions of GEM with atomic halogens, OH, OCl, and OBr. The accuracy of the calculations is assessed by comparing the calculated values against experimental data and also data from rigorous and computationally expensive state-of-the-art ab initio calculations. Bond dissociation energies (BDE) are determined from the heats of formation and used as a measure of the stability of the GOM species studied. The second goal of this work addresses the question of how can GOM species be measured in the atmosphere in real-time while retaining speciation information, using chemical ionization mass spectrometry. Ab initio and density functional theory calculations are used to determine structures of products of ion-molecule reactions and calculate associated reaction enthalpies and Gibbs free energies. The obtained data are used to identify reagent ions that can be used for atmospheric detection of GOM. The calculations provide an understanding of the complex ion-molecule chemistry that occurs during the chemical ionization process. The implications of this body of work are as follows. A low computational cost methodology is established that can be used to study a wide range of GOM species outside the scope of this work. The thermochemistry of the GOM species calculated in this work can serve as the foundation for future kinetic studies with the goal of improving the reaction mechanism in global transport models to provide a better understanding of the global mercury budget. Reagent ions identified in this work can be used for real-time speciation of GOM in the atmosphere, using chemical ionization mass spectrometry

A socio-ecological approach to align tree stewardship programs with public health benefits in marginalized neighborhoods in Los Angeles, USA

Extreme heat in the United States is a leading cause of weather-related deaths, disproportionately affecting low-income communities of color who tend to live in substandard housing with limited indoor cooling and fewer trees. Trees in cities have been documented to improve public health in many ways and provide climate regulating ecosystem services via shading, absorbing, and transpiring heat, measurably reducing heat-related illnesses and deaths. Advancing “urban forest equity” by planting trees in marginalized neighborhoods is acknowledged as a climate health equity strategy. But information is lacking about the efficacy of tree planting programs in advancing urban forest equity and public wellbeing. There is a need for frameworks to address the mismatch between policy goals, governance, resources, and community desires on how to green marginalized neighborhoods for public health improvement—especially in water-scarce environments. Prior studies have used environmental management-based approaches to evaluate planting programs, but few have focused on equity and health outcomes. We adapted a theory-based, multi-dimensional socio-ecological systems (SES) framework regularly used in the public health field to evaluate the Tree Ambassador, orPromotor Forestal, program in Los Angeles, US. The program is modeled after the community health worker model—where frontline health workers are trusted community members. It aims to address urban forest equity and wellbeing by training, supporting, and compensating residents to organize their communities. We use focus groups, surveys, and ethnographic methods to develop our SES model of community-based tree stewardship. The model elucidates how interacting dimensions—from individual to society level—drive urban forest equity and related public health outcomes. We then present an alternative framework, adding temporal and spatial factors to these dimensions. Evaluation results and our SES model highlight drivers aiding or hindering program trainees in organizing communities, including access to properties, perceptions about irrigation responsibilities, and lack of trust in local government. We also find that as trainee experience increases, measures including self- and collective efficacy and trust in their neighbors increase. Findings can inform urban forestry policy, planning, and management actions at the government and non-profit levels that aim to increase tree cover and reduce heat exposure in marginalized communities

Los contenidos educativos y la web semántica

Las aplicaciones informáticas educativas requieren que los contenidos educativos tengan un alto nivel de interoperabilidad, para poder explotar al máximo el potencial de la información digital y de los sistemas automatizados. En estos contextos, es necesario que los contenidos puedan utilizarse en diversas aplicaciones como las plataformas de aprendizaje, las bibliotecas digitales, los repositorios, los sistemas de información e incluso en los dispositivos móviles. Aunque hay estándares tecnológicos para que estas herramientas puedan comunicarse, los métodos de descripción utilizados requieren de mayor definición para empatar los significados de los descriptores y realizar un intercambio realmente eficiente de información y contenidos. La Web Semántica propone tecnologías que permitan un procesamiento más eficiente, aunado a estas tecnologías aparece un método para la descripción de la información, al que se conoce como ontologías. Las ontologías expanden las capacidades de los sistemas descriptivos actuales, como los tesauros y los metadatos. Un contenido educativo se encuentra inmerso en un ambiente complejo: usuarios con intereses diferentes, aplicaciones con tecnologías heterogéneas, contextos variables y usos diversos. El desarrollo de ontologías en este ámbito comienza a ser una necesidad, ya que los sistemas tradicionales de clasificación y organización de la información y del conocimiento tienen limitantes en su diseño que restringen el trabajo de tareas automáticas a los sistemas informáticos. Este trabajo hace un planteamiento general del uso de la Web Semántica en los contextos educativos y específicamente hace una revisión al tema del diseño de las ontologías y a las diferentes metodologías que hay para su desarrollo, con un planteamiento de aplicación dentro del ámbito de los contenidos educativos digitales. Palabras clave Ontologías, web semántica, contenidos educativos

Los contenidos educativos y la web semántica

Las aplicaciones informáticas educativas requieren que los contenidos educativos tengan un alto nivel de interoperabilidad, para poder explotar al máximo el potencial de la información digital y de los sistemas automatizados. En estos contextos, es necesario que los contenidos puedan utilizarse en diversas aplicaciones como las plataformas de aprendizaje, las bibliotecas digitales, los repositorios, los sistemas de información e incluso en los dispositivos móviles. Aunque hay estándares tecnológicos para que estas herramientas puedan comunicarse, los métodos de descripción utilizados requieren de mayor definición para empatar los significados de los descriptores y realizar un intercambio realmente eficiente de información y contenidos. La Web Semántica propone tecnologías que permitan un procesamiento más eficiente, aunado a estas tecnologías aparece un método para la descripción de la información, al que se conoce como ontologías. Las ontologías expanden las capacidades de los sistemas descriptivos actuales, como los tesauros y los metadatos. Un contenido educativo se encuentra inmerso en un ambiente complejo: usuarios con intereses diferentes, aplicaciones con tecnologías heterogéneas, contextos variables y usos diversos. El desarrollo de ontologías en este ámbito comienza a ser una necesidad, ya que los sistemas tradicionales de clasificación y organización de la información y del conocimiento tienen limitantes en su diseño que restringen el trabajo de tareas automáticas a los sistemas informáticos. Este trabajo hace un planteamiento general del uso de la Web Semántica en los contextos educativos y específicamente hace una revisión al tema del diseño de las ontologías y a las diferentes metodologías que hay para su desarrollo, con un planteamiento de aplicación dentro del ámbito de los contenidos educativos digitales. Palabras clave Ontologías, web semántica, contenidos educativos

Weldability study of alloys 625 and 718 fabricated by laser-based additive manufacturing

Funding Information: Francisco Werley Cipriano Farias acknowledges Fundação para a Ciência e a Tecnologia (FCT-MCTES) for funding his PhD Grant 2022.13870.BD. Publisher Copyright: © 2025 The AuthorsNickel-based alloys, Alloys 625 and 718, are widely used in the aerospace industry due to their excellent corrosion resistance and high strength at elevated temperatures. Recently, these alloys have been utilized to manufacture rocket engine components using additive manufacturing (AM) technologies such as laser powder bed fusion (LPBF) and powder-blown laser-based directed energy deposition (DED). These technologies offer faster and more cost-effective production while enabling the fabrication of near-net-shape parts that are subsequently joined by welding. However, solidification cracking susceptibility varies significantly between AM and conventionally processed materials, and limited weldability characterization has been conducted on AM-fabricated materials. This study assesses the weld solidification cracking susceptibility of Alloys 625 and 718 produced by wrought (mill-rolled), LPBF, and DED using transverse varestraint testing, Scheil-Gulliver simulations, the Crack Susceptibility Index (CSI), and the Flow Resistance Index (FRI). Transverse varestraint testing revealed that AM parts exhibited higher susceptibility due to the presence of larger and elongated grains in the fusion zone, affecting the weld solidification cracking response. In Alloy 625, the LPBF condition exhibited the highest maximum crack distance (MCD) of 2.35 ± 0.16 mm, compared to 1.56 ± 0.06 mm for wrought and 1.72 ± 0.10 mm for DED. Similarly, in Alloy 718, the DED condition showed the highest MCD of 2.93 ± 0.41 mm, while the wrought condition had an MCD of 2.01 ± 0.12 mm, and the LPBF condition reached 3.01 ± 0.33 mm at 5 % strain, without a clearly defined saturation strain. Although wrought materials demonstrated greater resistance to solidification cracking, solidification simulations did not correlate with the experimental testing, as they do not account for microstructural and mechanical factors, relying solely on chemistry.publishersversionpublishe

Micromechanical Properties of Injection-Molded Starch–Wood Particle Composites

The micromechanical properties of injection molded starch–wood particle composites were investigated as a function of particle content and humidity conditions. The composite materials were characterized by scanning electron microscopy and X-ray diffraction methods. The microhardness of the composites was shown to increase notably with the concentration of the wood particles. In addition,creep behavior under the indenter and temperature dependence were evaluated in terms of the independent contribution of the starch matrix and the wood microparticles to the hardness value. The influence of drying time on the density and weight uptake of the injection-molded composites was highlighted. The results revealed the role of the mechanism of water evaporation, showing that the dependence of water uptake and temperature was greater for the starch–wood composites than for the pure starch sample. Experiments performed during the drying process at 70°C indicated that the wood in the starch composites did not prevent water loss from the samples.Peer reviewe

Fruticultura orgánica en el trópico: Situación y ejemplos de Mesoamérica

La situación en la fruticultura orgánica de Mesoamérica no es fácil a cualificar y cuantificar. Indudablemente existen áreas certificadas sin embargo faltan datos exactos. En otra manera muchos campesinos cultivan frutas y vegetales sin el uso de fertilizantes inorgánicos y sin aplicaciones de pesticidazas por falta de insumos propios. Este estudio esta basado en ejemplos y practicas conocidas y trata a reflejar filosofías practicas del campesinado y las fortalezas y debilidades correspondientes. De lo mas énfasis se ha dedicado al chayote en Costa Rica y México, a la pitahaya en Nicaragua, a la papaya en el Estado Tabasco y al mango, rambutan y caña de azúcar en el estado Chiapas, México, y a las huertas familiares en Cuba. Resultados de una encuesta entre consumidores reflejan el interés para consumir productos orgánicos, establecer la interacción agricultores-consumidores como parte del proceso de desarrollo agroecológico y fortalecer la educación de los consumidores y productores en los aspectos agroecológicos y de salud

Type 2 Diabetes Variants Disrupt Function of SLC16A11 through Two Distinct Mechanisms

Type 2 diabetes (T2D) affects Latinos at twice the rate seen in populations of European descent. We recently identified a risk haplotype spanning SLC16A11 that explains ∼20% of the increased T2D prevalence in Mexico. Here, through genetic fine-mapping, we define a set of tightly linked variants likely to contain the causal allele(s). We show that variants on the T2D-associated haplotype have two distinct effects: (1) decreasing SLC16A11 expression in liver and (2) disrupting a key interaction with basigin, thereby reducing cell-surface localization. Both independent mechanisms reduce SLC16A11 function and suggest SLC16A11 is the causal gene at this locus. To gain insight into how SLC16A11 disruption impacts T2D risk, we demonstrate that SLC16A11 is a proton-coupled monocarboxylate transporter and that genetic perturbation of SLC16A11 induces changes in fatty acid and lipid metabolism that are associated with increased T2D risk. Our findings suggest that increasing SLC16A11 function could be therapeutically beneficial for T2D. Video Abstract [Figure presented] Keywords: type 2 diabetes (T2D); genetics; disease mechanism; SLC16A11; MCT11; solute carrier (SLC); monocarboxylates; fatty acid metabolism; lipid metabolism; precision medicin

Global, regional, and national burden of tuberculosis, 1990–2016: results from the Global Burden of Diseases, Injuries, and Risk Factors 2016 Study

Background Although a preventable and treatable disease, tuberculosis causes more than a million deaths each year. As countries work towards achieving the Sustainable Development Goal (SDG) target to end the tuberculosis epidemic by 2030, robust assessments of the levels and trends of the burden of tuberculosis are crucial to inform policy and programme decision making. We assessed the levels and trends in the fatal and non-fatal burden of tuberculosis by drug resistance and HIV status for 195 countries and territories from 1990 to 2016. Methods We analysed 15 943 site-years of vital registration data, 1710 site-years of verbal autopsy data, 764 site-years of sample-based vital registration data, and 361 site-years of mortality surveillance data to estimate mortality due to tuberculosis using the Cause of Death Ensemble model. We analysed all available data sources, including annual case notifications, prevalence surveys, population-based tuberculin surveys, and estimated tuberculosis cause-specific mortality to generate internally consistent estimates of incidence, prevalence, and mortality using DisMod-MR 2.1, a Bayesian meta-regression tool. We assessed how the burden of tuberculosis differed from the burden predicted by the Socio-demographic Index (SDI), a composite indicator of income per capita, average years of schooling, and total fertility rate. Findings Globally in 2016, among HIV-negative individuals, the number of incident cases of tuberculosis was 9·02 million (95% uncertainty interval [UI] 8·05–10·16) and the number of tuberculosis deaths was 1·21 million (1·16–1·27). Among HIV-positive individuals, the number of incident cases was 1·40 million (1·01–1·89) and the number of tuberculosis deaths was 0·24 million (0·16–0·31). Globally, among HIV-negative individuals the age-standardised incidence of tuberculosis decreased annually at a slower rate (–1·3% [–1·5 to −1·2]) than mortality did (–4·5% [–5·0 to −4·1]) from 2006 to 2016. Among HIV-positive individuals during the same period, the rate of change in annualised age-standardised incidence was −4·0% (–4·5 to −3·7) and mortality was −8·9% (–9·5 to −8·4). Several regions had higher rates of age-standardised incidence and mortality than expected on the basis of their SDI levels in 2016. For drug-susceptible tuberculosis, the highest observed-to-expected ratios were in southern sub-Saharan Africa (13·7 for incidence and 14·9 for mortality), and the lowest ratios were in high-income North America (0·4 for incidence) and Oceania (0·3 for mortality). For multidrug-resistant tuberculosis, eastern Europe had the highest observed-to-expected ratios (67·3 for incidence and 73·0 for mortality), and high-income North America had the lowest ratios (0·4 for incidence and 0·5 for mortality). Interpretation If current trends in tuberculosis incidence continue, few countries are likely to meet the SDG target to end the tuberculosis epidemic by 2030. Progress needs to be accelerated by improving the quality of and access to tuberculosis diagnosis and care, by developing new tools, scaling up interventions to prevent risk factors for tuberculosis, and integrating control programmes for tuberculosis and HIV