La regulación de los recursos naturales en proyectos de ingeniería civil constituye uno de sus principales pilares para el desarrollo sostenible, especialmente en aquellos espacios donde la extracción y uso de recursos como la arena, los sedimentos y los residuos de la construcción son capaces de propiciar altos impactos ambientales. Esta revisión sistemática indaga en investigaciones recientes en gobernanza sobre la extracción de arena, la economía circular de la construcción, las prácticas de dragado, las compras públicas ecológicas y las evaluaciones de impacto ambiental, con el objetivo de determinar alternativas que concilien el avance económico con la protección/conciencia ecológica. Se incorporan veintinueve artículos seleccionados en función de los criterios de inclusión criterios de idoneidad temáticas y robustez metodológica para regiones como Ghana, Malasia, Vietnam y otras partes del mundo. Los resultados destacan que la extracción ilegal de la arena degrada la fertilidad del suelo y las comunidades agrícolas; la economía circular genera menos desperdicio debido al reciclado de materiales; las políticas de compras públicas ecológicas extreman los criterios ambientales aplicados a las licitaciones; y la evaluación de impacto ambiental demanda simplificaciones de los modelos de forma coherente para no provocar un cierto retraso, pero, a la vez, sin limitar una cierta protección.
Philipp Treu, Dimitra Iltsiou, Rabia Elbuga-Ilica
et al.
The oxidative cleavage of biomass-derived vicinal diols holds significant potential for producing valuable renewable carboxylic acids. Fe-ZSM-5 zeolite is a highly effective catalyst for this reaction using mild reaction conditions; however, it suffers from diffusion limitations, particularly with larger substrates. To overcome these challenges, we synthesized hierarchical ZSM-5 zeolite that integrate mesopores within the conventional microporous framework, thereby mitigating diffusion constraints. These hierarchical materials were developed using carbon templating and desilication techniques. Carbon templating led to the creation of well-defined mesopores, while desilication facilitated the formation of hollow crystals. The mesopore-containing hierarchical zeolites led to increased ion-exchange capacity, due to enhanced accessibility of exchange positions for the Fe3 + cations, with the desilicated zeolite exceeding the Fe-loading by 3.5 times that of the microporous parent ZSM-5 material, as observed by UV–vis spectroscopy, EXAFS analysis and elemental analysis by ICP-OES. Catalytic tests revealed that hierarchical Fe-ZSM-5 catalysts exhibit superior performance compared to their purely microporous counterparts. Specifically, desilication improved catalytic activity for smaller substrates, while carbon templating proved more effective for larger vicinal diols. Furthermore, the carbon templated zeolite displayed enhanced activity per Fe-site, highlighting the benefits of hierarchical porosity in optimizing catalytic performance.
Existing image processing and target recognition algorithms have limitations in complex underwater environments and dynamic changes, making it difficult to ensure real-time and precision. Multiple noise sources interfere with sonar signals, which affects both data precision and clarity. This article studies the dynamic display algorithm of sonar data based on grayscale distribution model and computational intelligence. It proposes to construct a grayscale distribution model for sonar images, analyze the grayscale histogram, determine the threshold selection of the maximum entropy threshold segmentation method, and finally complete the target segmentation. The segmented images can be used to train the convolutional neural network object recognition model constructed in this article. To verify the effectiveness of the proposed method, a test set was used to evaluate the trained target recognition model. The precision of the model recognition was 87.95%, the recall was 87.97%, and the F1 value was 0.8794, which is significantly higher than the traditional model (Such as Otsu and SVM is below 80%). The recognition speed reached 37 m, which is a certain improvement compared to the traditional model.
Defects in pipes adversely affect both the jacking construction process and long-term operational safety, yet their specific impacts on mechanical properties remain unclear. This study investigates pipe jacking segments under deflection, using the Changsha Meixi Lake project as a case study. Similar model tests combined with digital image correlation were employed to examine the evolution of stress and deformation under various deflection angles and defect conditions. The reliability of the laboratory tests was verified through theoretical stress calculations under the non-deflection condition. The credibility of the laboratory test results was further enhanced by employing a numerical model and normalized parameters. Key findings reveal that stress distribution characteristics are jointly determined by the deflection mode and load. Co-directional deflection exhibits a more significant stress concentration effect; under identical load and angle conditions, it results in higher stress levels due to a superposition effect, whereas diagonal deflection shows a weakening effect. Joint deformation progresses through three distinct stages. The linear growth stage exhibits an initial linear strain–load relationship under stable deflection (load < 2 kN). The accelerated deformation stage is characterized by nonlinear strain growth with a slowing deformation rate (2–4 kN). The deformation deceleration stage finally shows a slow linear strain increment (load > 4 kN). Increasing load and deflection angle significantly amplify axial deformation, particularly revealing a “thick-in-the-middle, thin-at-the-sides” compression characteristic in the 45° vault zones. Furthermore, segment defects markedly exacerbate stress non-uniformity. Defect angles ≥ 60° substantially increase the frequency and amplitude of compressive stress in the vault, accelerate the decay of tensile stress at the bottom, and critically reduce structural stability. These new findings provide significant insights for deflection control and structural safety assessment in pipe jacking engineering. The experimental framework provides fundamental insights into construction operations in upper-soft and lower-hard strata tunneling.
Madhu Surana, Dhruti Sundar Pattanayak, V.K. Singh
et al.
Graphitic carbon nitride (g-C3N4) has garnered significant attention due to its low cost, ease of preparation, high chemical stability, and non-toxicity. Nevertheless, pristine g-C3N4 faces challenges in simultaneously achieving a broad absorption range, high stability, efficient charge separation, and strong redox capability, which hampers its practical applications. Recently, g-C3N4-based Z-scheme photocatalysts have emerged as research hotspots owing to their robust redox ability, effective charge carrier separation, and capacity to harness visible light for degradation of tetracyclines (TCs) in waters. This review delves into the fundamental photocatalysis, and application of g-C3N4-based Z-scheme photocatalysts for the degradation of TCs pollutants. The review concludes with final remarks and a concise discussion on the prospects of g-C3N4-based Z-scheme photocatalysts.
Julian R. Greenwood, Vanica Lacorte-Apostol, Thomas Kroj
et al.
Abstract A critical step to maximize the usefulness of genome-wide association studies (GWAS) in plant breeding is the identification and validation of candidate genes underlying genetic associations. This is of particular importance in disease resistance breeding where allelic variants of resistance genes often confer resistance to distinct populations, or races, of a pathogen. Here, we perform a genome-wide association analysis of rice blast resistance in 500 genetically diverse rice accessions. To facilitate candidate gene identification, we produce de-novo genome assemblies of ten rice accessions with various rice blast resistance associations. These genome assemblies facilitate the identification and functional validation of novel alleles of the rice blast resistance genes Ptr and Pia. We uncover an allelic series for the unusual Ptr rice blast resistance gene, and additional alleles of the Pia resistance genes RGA4 and RGA5. By linking these associations to three thousand rice genomes we provide a useful tool to inform future rice blast breeding efforts. Our work shows that GWAS in combination with whole-genome sequencing is a powerful tool for gene cloning and to facilitate selection of specific resistance alleles for plant breeding.
C. P. B. O'Malley, C. P. B. O'Malley, G. G. Roberts
et al.
<p>The modern state of the mantle and its evolution on geological timescales are of widespread importance for the Earth sciences. For instance, it is generally agreed that mantle flow is manifest in topographic and drainage network evolution, glacio-eustasy, and the distribution of sediments. There are now a variety of theoretical approaches to predict histories of mantle convection and its impact on surface deflections. A general goal is to make use of observed deflections to identify Earth-like simulations and constrain the history of mantle convection. Several important insights into the role of radial and non-radial viscosity variations, gravitation, and the importance of shallow structure already exist. Here we seek to bring those insights into a single framework to elucidate the relative importance of popular modeling choices for predicted instantaneous vertical surface deflections. We start by comparing results from numeric and analytic approaches to solving the equations of motion that are ostensibly parameterized to be as similar as possible. Deflections predicted by such numeric and analytic models can vary by <span class="inline-formula">∼</span> 10 %, and the difference increases to <span class="inline-formula">∼</span> 25 % when viscosity is temperature-dependent. Including self-gravitation and the gravitational potential of the deflected surface is a relatively small source of discrepancy. However, spherical harmonic correlations between model predictions decrease dramatically with the removal of shallow structure to increasing depths and when radial viscosity structure is modified. The results emphasize the sensitivity of instantaneous surface deflections to density and viscosity anomalies in the upper mantle. They reinforce the view that a detailed understanding of lithospheric structure is crucial for relating mantle convective history to observations of vertical motions at Earth's surface.</p>
The planetary boundaries framework defines a safe operating space for humanity. To date, these boundaries have mostly been investigated separately, and it is unclear whether breaching one boundary can lead to the transgression of another. By employing a dynamic global vegetation model, we systematically simulate the strength and direction of the effects of different transgression levels of the climate change boundary (using climate output from ten phase 6 of the Coupled Model Intercomparison Project models for CO _2 levels ranging from 350 ppm to 1000 ppm). We focus on climate change-induced shifts of Earth’s major forest biomes, the control variable for the land-system change boundary, both by the end of this century and, to account for the long-term legacy effect, by the end of the millennium. Our simulations show that while staying within the 350 ppm climate change boundary co-stabilizes the land-system change boundary, breaching it (>450 ppm) leads to critical transgression of the latter, with greater severity the higher the ppm level rises and the more time passes. Specifically, this involves a poleward treeline shift, boreal forest dieback (nearly completely within its current area under extreme climate scenarios), competitive expansion of temperate forest into today’s boreal zone, and a slight tropical forest extension. These interacting changes also affect other planetary boundaries (freshwater change and biosphere integrity) and provide feedback to the climate change boundary itself. Our quantitative process-based study highlights the need for interactions to be studied for a systemic operationalization of the planetary boundaries framework.
Julia R. Varshavsky, Swati D. G. Rayasam, Jennifer B. Sass
et al.
Abstract A key element of risk assessment is accounting for the full range of variability in response to environmental exposures. Default dose-response methods typically assume a 10-fold difference in response to chemical exposures between average (healthy) and susceptible humans, despite evidence of wider variability. Experts and authoritative bodies support using advanced techniques to better account for human variability due to factors such as in utero or early life exposure and exposure to multiple environmental, social, and economic stressors. This review describes: 1) sources of human variability and susceptibility in dose-response assessment, 2) existing US frameworks for addressing response variability in risk assessment; 3) key scientific inadequacies necessitating updated methods; 4) improved approaches and opportunities for better use of science; and 5) specific and quantitative recommendations to address evidence and policy needs. Current default adjustment factors do not sufficiently capture human variability in dose-response and thus are inadequate to protect the entire population. Susceptible groups are not appropriately protected under current regulatory guidelines. Emerging tools and data sources that better account for human variability and susceptibility include probabilistic methods, genetically diverse in vivo and in vitro models, and the use of human data to capture underlying risk and/or assess combined effects from chemical and non-chemical stressors. We recommend using updated methods and data to improve consideration of human variability and susceptibility in risk assessment, including the use of increased default human variability factors and separate adjustment factors for capturing age/life stage of development and exposure to multiple chemical and non-chemical stressors. Updated methods would result in greater transparency and protection for susceptible groups, including children, infants, people who are pregnant or nursing, people with disabilities, and those burdened by additional environmental exposures and/or social factors such as poverty and racism.
Industrial medicine. Industrial hygiene, Public aspects of medicine
Abstract The Median Tectonic Line (MTL) is an arc-parallel strike-slip fault that accommodates much of the arc-parallel component of the oblique convergence of the Philippine Sea and Eurasian plates at the Nankai Trough. The MTL in Shikoku is one of the fastest-slipping faults in Japan, with a late Quaternary right-lateral slip rate of 5–10 mm/yr. To estimate the right-lateral slip amounts of the past faulting events on the MTL, we acquired 2D and pseudo-3D ground-penetrating radar (GPR) sections across the ENE-trending Ikeda fault of the MTL in eastern Shikoku. We conducted the GPR surveys at the Higashi-Miyoshi site, where two terrace riser offsets mark the active fault trace. The 2D lines were about 28–64 m long, and the pseudo-3D data were sized 20 m × 30 m with a 0.5-m inline spacing. We used 50 MHz GPR antennas and conducted wide-angle measurements to estimate the electromagnetic wave velocity. We identified three paleochannels on the final depth-converted GPR sections, and two of them are deflected by the fault. A paleochannel at 0.6–1.4 m depth is observed on all inline sections of the pseudo-3D GPR data. We built a 3D model of this paleochannel and estimated the right-lateral and vertical displacements of ~ 3.5 m and ~ 0.5 m, respectively. This paleochannel offset is probably caused by the most recent surface-rupturing earthquake on the Ikeda fault, which may be the 1596 Keicho-Fushimi earthquake. This study demonstrates the usefulness of the GPR surveys to identify geological features displaced laterally and vertically by the most recent surface-rupturing earthquake.
<p>The Bay of Bengal is a well-known breeding ground to some of the deadliest cyclones in history. Despite recent advancements, the complex morphology and hydrodynamics of this large delta and the associated modelling complexity impede accurate storm surge forecasting in this highly vulnerable region. Here we present a proof of concept of a physically consistent and computationally efficient storm surge forecasting system tractable in real time with limited resources. With a state-of-the-art wave-coupled hydrodynamic numerical modelling system, we forecast the recent Supercyclone Amphan in real time. From the available observations, we assessed the quality of our modelling framework. We affirmed the evidence of the key ingredients needed for an efficient, real-time surge and inundation forecast along this active and complex coastal region. This article shows the proof of the maturity of our framework for operational implementation, which can particularly improve the quality of localized forecast for effective decision-making over the Bengal delta shorelines as well as over other similar cyclone-prone regions.</p>
Cheleleka peatland is located at the eastern side of Lake Hawassa and its biological communities face a variety of anthropogenic factors such as agricultural expansion, water diversion, settlement and subsequent peatland drainage and peat extraction. The decomposing products were influenced by various anthropogenic activities. This study aims to identify the impact of human activities on peat characteristics. The result indicates that the peat soil is acidic having a pH value ranging from 4.1-to-4.7 and containing humic acid due to excessive accumulation of organic matter and nutrients. The maturity level of the peat was almost similar in all study sites, except for the Daka site, and are classified under mostly decomposed. At Wesha, Werka, Wendo, Shalo, Cheffe, and Wendo, sites the maturity of the peat was classified under sapric soil. Exceptionally, at Daka Site, the peat maturity level was hemic. The percentage of sand, clay, and silt of the peatland range 40-50% clay, 30-40% silt and 10-20% sandy. The mean organic carbon content of Cheleleka peatland ranged from 4.48 to 38.65% and positively correlated with the thickness of the peat and negatively correlated with the ash content of the peat. The main effects of unsustainable landuse practice on peatland are peat reduction/complete loss, reduce water and nutrient retention capacity due to drainage and compaction of peat due to overgrazing. Changes in drainage, vegetation cover, and extraction of peat had resulted in differing outcomes from decomposition processes, and the properties of peats on the disturbed sites had changed.
Wills Adam, Banister Carsen, Pellissier Mathieu
et al.
This work explores the importance of renewable resource temporal distribution for solar and wind energy deployment in Arctic communities to meet building and ancillary loads. An analysis of ten years of historic weather data was performed for six locations in the Canadian Arctic to assess renewable resource variation. Simulations of similar capacity solar and wind generation systems were then coupled with the historic data to compare and contrast generation potential. This analysis highlighted the importance of considering hourly, daily, monthly, and year-to-year renewable generation when deploying solar and wind to the Arctic. As many northern communities in Canada have local electricity generation and distribution systems, and no connection to the continental grid, managing grid interactions effectively is crucial to the success of deployment, integration, and operation. The results for the solar energy analysis showed high consistency of production year-to-year. The results for the wind energy analysis showed that the annual outputs have significantly less variation than the year-to-year output of individual months for all the locations under study. For the high latitude locations studied, solar energy can still provide useful electricity generation output, but the more pronounced bias of the annual output to the summer months can leave several months with little or no output. The use of additional renewable sources is crucial in beginning to transition some electricity generating capacity within Arctic communities from being solely reliant on fossil fuels.
Chicken liver is a main protein source to prepare attractant for dog food. However, animal proteins are costly. Seeking high quality and low-cost protein sources has been a goal for the industry. Mushroom Lentinus edodes (L. edodes) and Mealworm Tenebrio molitor (T. molitor) are novel protein sources, showing high potential as raw material of attractants. In this paper, chicken liver, L. edodes, and T. molitor were used as three different protein sources to prepare attractants. Their palatability to dogs were then compared. Firstly, the enzymatic hydrolysis process of three proteins was optimized, with a degree of hydrolysis of 54.82%, 36.10% and 30.14% for chicken liver, L. edodes, and T. molitor respectively. Secondly, volatile compounds of three attractants were identified by HS-SPME/GC-MS and SDE/GC-MS. Using OAV and PLRS method, it was found that bis(2-methyl-3-furyl) disulfide, indole, methional, 2-(methyl thio) phenol, γ-butyrolacton, furfuryl alcohol, acetic acid and isovaleraldehyde were the key components. Although both T. molitor and L. edodes attractant showed less palatability than that of chicken liver, they could be readily improved via adding key palatable volatile compounds. The ingestion rate of dog food with attractant showed a similar trend and was higher than that of food without attractant.
In contrast to recent advances in projecting sea levels, estimations
about the economic impact of sea level rise are vague.
Nonetheless, they are of great importance for policy making with
regard to adaptation and greenhouse-gas mitigation. Since the
damage is mainly caused by extreme events, we propose a stochastic
framework to estimate the monetary losses from coastal floods in
a confined region. For this purpose, we follow
a Peak-over-Threshold approach employing a Poisson point process and
the Generalised Pareto Distribution. By considering the effect of
sea level rise as well as potential adaptation scenarios on the
involved parameters, we are able to study the development of the
annual damage. An application to the city of Copenhagen shows that
a doubling of losses can be expected from a mean sea level increase
of only 11 cm. In general, we find that for varying
parameters the expected losses can be well approximated by one of
three analytical expressions depending on the extreme value
parameters. These findings reveal the complex interplay of the
involved parameters and allow conclusions of fundamental relevance.
For instance, we show that the damage typically increases faster than
the sea level rise itself. This in turn can be of great importance
for the assessment of sea level rise impacts on the global scale.
Our results are accompanied by an assessment of uncertainty, which
reflects the stochastic nature of extreme events.
While the absolute value of uncertainty about the flood damage
increases with rising mean sea levels, we find that it decreases
in relation to the expected damage.