Search

Agricultural Non-Point Source Pollution (ANSP) has posed a great challenge in modern agriculture worldwide, due mainly to the massive application of fertilizers and pesticides in fields. It is of great significance to develop ecological restoration technologies to mitigate the ANSP. Among them, an ecological ditch can function as a farmland drainage ditch and constructed wetland in recent years. Most previous studies have focused on the dissipation mechanisms of nitrogen (N) and phosphorus (P). However, it is still lacking in the pesticide removal in the ecological ditch. Meanwhile, it is a high demand for the multiple factors analysis rather than the commonly-used single factor analysis, because the dissipation mechanisms of the ecological ditch were influenced by the interaction of multiple factors. In this review, a literature survey was performed on the field experiments of ecological ditches using the ISI Web of Science and CNKI databases from 2001 to 2022. The dissipation mechanisms of ANSP included sediment sorption and plant resistance, as well as plant/microorganism absorption and degradation. The search criteria involved field experiment, ecological ditch or drainage ditch, and ANSP. A total of 559 groups of field experimental data were analyzed to explore the removal rates of total nitrogen, ammonia nitrogen, nitrate nitrogen, total phosphorus, orthophosphate, and pesticides. Four influencing factors were taken into account, i.e., the Initial Contaminant Concentration (IC), Hydraulic Retention Time (HRT), Plant Species (PS), and Plant Biomass (BM). Other influencing factors were also discussed, such as the temperature, hydraulic load, rainfall, and alternate wetting and drying. Both single and multiple factors analysis were carried out using correlation analysis and Multiple Linear Regression Model (MLR), respectively. The results indicated that both total nitrogen and total phosphorus increased as the IC, HRT and BM increased (P<0.01), while the PS had no significant correlation with total nitrogen and total phosphorus (P>0.05). The reason was that the sorption and uptake processes were stimulated by the higher IC, HRT and BM, whereas, the resuspension was inhibited by the higher HRT and BM in the ecological ditch. The MLR analysis demonstrated that the coefficient of determination (R²) was 0.80 and 0.92 for the total nitrogen and total phosphorus, respectively. Both the IC and BM showed a positive correlation with the total nitrogen and total phosphorus (P<0.05). Therefore, the high IC and BM greatly contributed to the high total nitrogen and total phosphorus. Particularly, the contribution ratio of IC was higher than that of BM in the MLR equations for the total nitrogen and total phosphorus. The high concentration gradient was attributed to the contribution of the ecological ditch. The diffusion of nutrients was promoted from the overlying water to pore water in the sediment. As such, more favorable absorption conditions were provided for the sediment microorganisms and plants. The single-factor analysis indicated that the pesticide declined as the IC raised (P<0.05), in terms of pesticides. The toxicity of pesticides might inhibit the pesticide-degradation ability of the microorganisms and plants in high IC condition, further weakening the metabolic activity of microorganisms and the absorption of plants. The pesticides raised significantly, as the HRT increased (P<0.05), indicating the longer microbial reaction for the higher pesticide removal rate. Besides, the MLR equation for the pesticides showed reliable statistical parameters in the training set with the R²=0.56. The pesticides in the MLR were negatively correlated with the IC (P<0.05), but positively correlated with the HRT (P<0.05), which were consistent with the single-factor analysis. Therefore, it is very necessary to supplement the experimental research on the interaction of multiple factors in the future. It is also of great significance to investigate the other hydrologic and environmental factors on the removal efficiencies of ecological ditches. Future research can also explore the effects of pesticide structures and microbiological mechanisms on pesticide removal in ecological ditches. [ABSTRACT FROM AUTHOR]

Ditch plant biomass and diversity play an important role in maintaining ditch ecosystem structure and function stability, which are subject to environmental changes. However, the regulation of abiotic factors on the aboveground biomass and diversity of plants on the slopes of coastal agricultural ditches remains unclear. In this study, the spatial distribution of soil physicochemical properties, aboveground biomass, and diversity of vegetation on different slope positions (upper slope, middle slope, and lower slope) and slope aspects (north-south direction) of farmland drainage ditches and their correlations were investigated through field surveys of vegetation on the slopes of coastal farmland drainage ditches at different sampling sites. First, water content and bulk density) decreased with the increase of slope position, while the salinity showed the opposite spatial distribution characteristics and the distribution of soil nutrients in space was mainly concentrated in the 0–20 cm soil layer. Second, the aboveground biomass of vegetation was significantly higher on the south slope than on the north slope, with the highest biomass at the lower slope on the south slope and higher aboveground biomass on the north slope at the upper and middle slopes. The Shannon-Wiener index, Pielou index, and Margalef index of ditch slope vegetation in Dongying and Binzhou farmland ditch slopes showed the same pattern of change at different slope positions and directions, which were significantly higher at the upper and middle slopes than at the lower slopes. In contrast, the Simpson index showed the opposite pattern, decreasing with the increase in slope position. Further, WC, BD, organic matter content, and total nitrogen content had positive effects on vegetation aboveground biomass, while soil pH, salinity, and available potassium content hindered vegetation growth. Finally, the Shannon-Wiener index and Pielou index were positively correlated with soil BD and available phosphorus content, and negatively correlated with organic matter and total nitrogen content, while the Simpson index was positively correlated with soil BD and WC, and had a significant negative correlation with soil salinity. [ABSTRACT FROM AUTHOR]

These included a series of boundary ditches, possible remnants of light structures consisting of post-holes and pits, and a re-cut of a late Bronze Age boundary ditch. The pit was joined at one end by another deep pit, possibly suggesting a kiln and firepit combination, but this has yet to be substantiated by further excavation in 2022. (1) B Bracknell b , I land at Tilehurst Lane, Binfield, i (SU 8955 6995): a small excavation[1] revealed an urned Late Iron Age cremation burial, in a vase-like grog-tempered vessel, which produced a radiocarbon date of 52 cal b.c. [Extracted from the article]

(1) I Crosby Square, 22 Bishopsgate i (TQ 33151 81236): an archaeological excavation and watching-brief (YSQ19), started in 2019, continued in 2020.[1] The initial watching-brief led to the identification of two areas of higher archaeological survival: the UK Power Networks (UKPN) chamber and the Gas Vault (the northernmost of two vaults belonging to the Hiscox building, also called the "gas monitoring room"). To the south of the stumps a substantial north-west to south-east ditch was recorded, sealed by alluvial layers overlain by a succession of ground-raising deposits, which were a likely response to seasonal inundations from the Walbrook. Directly above the ground-raising layers an east-west structure consisting of clay floor slabs and beam-slots was encountered. [Extracted from the article]

Mines inevitably generate various environmental geological problems when carrying out production operations, which have serious impacts on the surrounding environment, especially the open-pit mining operation, which is more obviously destructive to the environment. The current environmental and geological problems of the mine are analyzed and the corresponding management measures are discussed, taking the Dulan Chahanwusu construction stone mine as the research object. The results of the study show that the main environmental geological problems of the mine are the development of several unstable mining slopes, the phenomenon of water-bearing layers, land resources, topography, and geomorphological destruction. At the same time, seven kinds of treatment measures were proposed for the above environmental geological problems, namely, dangerous rock mass and gravel cleaning, cutting slope and back pressure, drainage ditch construction, site backfill and leveling, net fence and warning sign engineering, earthing and revegetation engineering. The content of this discussion may have some theoretical and practical significance for the management of environmental geological problems in similar mines. [ABSTRACT FROM AUTHOR]

Lotic freshwater ecosystems are among the most threatened ecosystems worldwide due to the effects of multiple stressors, such as intensive land use in their catchments, morphological alterations, flow regulation, pollution, and climate change. Odonata are often used as valuable indicators of ecological integrity and anthropogenic disturbance of freshwater habitats. Here, we present the results of a study on Odonata assemblages in anthropogenically impacted habitats (hydropower plant reservoirs, tailrace canals, drainage ditches, and old river channels) conducted over a nine-year period. The negative impacts of anthropogenic activities on inhabiting biota were confirmed—with only 11 species recorded, the Odonata assemblages were species-poor and had low population densities. Although most species recorded were generalists, some species of national conservation concern were detected. Among the physico-chemical water parameters, the concentrations of ammonium, orthophosphates, nitrates, and mineral oils in the water were found to be the most important determinants of Odonata assemblages. The preservation of near-natural sites in the vicinity of anthropogenically impacted and man-made habitats is important for maintaining the local Odonata fauna and for the preservation of rare species. Our results highlight the importance of long-term data for determining the occurrence of Odonata species and monitoring their population dynamics. [ABSTRACT FROM AUTHOR]

Emerging aquatic insects constitute one of the main biological flows connecting aquatic and terrestrial ecosystems. In a landscape, there are many sources of emergence, which vary in space and time. Thus, they must be clearly defined when studying the inland dispersal of aquatic insects. In this study, we defined five types of hydrographic networks (including or not including ponds and ditches) on the basis of cartographic data of varying degrees of detail (from OpenStreetMap to field map) in order to explain the abundance of aquatic insects. We sampled Ephemeroptera, Plecoptera, Trichoptera, and Megaloptera (ETPM) with 64 sticky traps homogeneously covering a 75 ha agricultural landscape. The abundance of aquatic insects is logically better explained by the hydrographic networks recorded directly in the field than by the reference network, which is incomplete (OpenStreetMap). The results show that, depending on the sampling period, not all water bodies in the landscape are necessarily sources of emergence. To our knowledge, the issue of defining the sources of emerging aquatic insects has never been raised. Based on a practical example, this short note shows that, by refining the hydrographic network to better match the sources of emergence, the explanatory power of inland aquatic insect abundance can be greatly improved. [ABSTRACT FROM AUTHOR]

The ecological and health risks posed by wastes discharged from mining areas to the environment and human health has aroused concern. 114 soil samples were collected from nine areas of long-term mine waste land in northwestern Yunnan to assess the pollution characteristics, ecological and health risks of heavy metals. The result revealed that the geo-accumulation indexes were Cd (4.00) > Pb (3.18) > Zn (1.87) > Cu (0.25). Semi-variance analysis revealed that Cd and Cu showed moderate spatial dependency, whereas Pb and Zn showed strong spatial dependency. Cd posed an extreme potential ecological risk. Slopes and ditches were extreme potential ecological risk areas. Non-carcinogenic risk to children from Pb and Carcinogenic risk to adult and children from Cd was non-negligible and direct ingestion was the major source. This study provided a scientific basis for policymakers in management and exposure reduction. [ABSTRACT FROM AUTHOR]

Inorganic mercury (Hg) can be methylated to the highly toxic and bioavailable methylmercury (MeHg) by microorganisms in anaerobic environments. The Hg methylation rate may be affected by forest management activities, which can influence the catchment soils, water, and sediments. Here, we investigate the influence of forest management in the form of ditch cleaning and beaver dam removal, as well as the seasonal variations, on sediment chemistry and microbiota. The relationships between MeHg concentrations in sediment samples and archaeal and bacterial communities assessed by 16S rRNA gene amplicon sequencing were investigated to determine the microbial conditions that facilitated the formation of MeHg. Concentrations of MeHg were highest in undisturbed catchments compared to disturbed or slightly disturbed sites. The undisturbed sites also had the highest microbial diversity, which may have facilitated the formation of MeHg. Low MeHg concentrations and microbial diversity were observed in disturbed sites, which may be due to the removal of organic sediment layers during ditch cleaning and beaver dam removal, resulting in more homogenous, mineral-rich environments with less microbial activity. MeHg concentrations were higher in summer and autumn compared to winter and spring, but the temporal variation in the composition and diversity of the microbial community was less than the spatial variation between sites. Beta diversity was more affected by the environment than alpha diversity. The MeHg concentrations in the sediment were positively correlated to several taxa, including Cyanobacteria, Proteobacteria, Desulfobacterota, Chloroflexi, and Bacteroidota, which could represent either Hg-methylating microbes or the growth substrates of Hg-methylating microbes. [ABSTRACT FROM AUTHOR]

This paper aims to solve the problems of the low quality and shallow depth of the traditional straw return method. According to the requirements of the new furrow burial and return agronomic model, a corn straw ditch-buried returning machine was designed that could simultaneously complete the processes of picking, conveying, ditching, soil-covering and pressing. Key components were theoretically analyzed and designed, such as the pickup device, ditching device and straw-guiding soil-covering and pressing device. Based on a field experiment, the main factors influencing the effects of straw picking, soil ditching and straw return were studied. Both forward speed and pickup device speed significantly affected the straw picking rate. The ditching area, ditching width consistency factor and ditching depth stability factor gradually decreased with increasing forward speed and gradually increased with increasing trenching device speed. There was a significant interaction among the forward speed, pickup device speed and ditching device speed. At a forward speed of 1.68 m/s, the picking device speed was 330 r/min, the ditching device speed was 290 r/min, and the highest straw return rate was 93.65%. [ABSTRACT FROM AUTHOR]

Under the background of frequent hostile takeover events in China and the autonomy of the articles of association, the articles of association of listed companies even set up antitakeover provisions with an excessive defense that unreasonably restricts the rights of shareholders. Based on the role orientation of innovative supervision, the Small and Medium-sized Investors Service Center (hereinafter referred to as "Investment and Service Center") proposes to modify the relevant noncompliance provisions in the form of a shareholder recommendation letter. As the basic requirements of the articles of association and the relevant laws in corporate governance are increasingly inconsistent, the legal review of the articles of association is particularly important. This article determines the identification standard of excessive defense of antitakeover provisions by manually collecting the shareholder suggestion letter of the investment service center, the announcement on amendment of association articles of listed companies, and relevant laws and regulations. On this basis, the PSM-DID quasi-natural experimental method is used to empirically test the impact of excessive defense of antitakeover provisions on enterprise value. The study finds that the excessive defense of antitakeover provisions significantly inhibited the enterprise value. In this article, taking a-share listed companies in Shanghai and Shenzhen stock markets in 2007–2018 as an example, with the construction of antiacquisition clause excessive defense index (ATP end), relying on the "quasi-natural experiment" method of PSM-DID, we discuss the impact of excessive defense antiacquisition clause on the value of the enterprise and its impact path analysis. Further study found that its restriction mechanism was reflected in the significant increase of the first type of agency cost and the second type of agency cost. At the same time, the correlation between management compensation and performance and the correlation between management and professional performance are further reduced. Excessive defense against antiacquisition terms can reduce the corporate value, and the impact path of this effect is achieved by increasing type 1 agent costs and type 2 agent costs. It shows that the controlling shareholders are more likely to collude with the management, which aggravates the agency problem. The research conclusion of this article provides legal and economic empirical evidence for listed companies to reasonably set up antitakeover provisions and is also of great significance to innovative regulatory methods such as investment service centers. Excessive defense against antitakeover terms will enhance the dual-ditch effect and ultimately damage corporate value. [ABSTRACT FROM AUTHOR]

Dirre Sheikh Hussein is a religious complex in Ethiopia that dates from the 12th century or earlier. An important focus for pilgrimage, it lies in an isolated part of Oromia State on poorly drained semi-arid lowlands. Significant architecturally and culturally, recent expansion and refurbishment of the major buildings led to structural issues, though these are now largely overcome through consolidation of the prayer hall roof, laying a stone walkway, digging drainage ditches etc. Current deterioration of the buildings can be seen as: (i) fading of colours, (ii) cracks in walls, roofs, and festive places, (iii) deposits of sand around walls and (iv) staining and drainage marks on the white painted surfaces. Heavy falls of rain overwhelm drainage and overfill storage pools. Meteorological observations are infrequent locally, so those made some 70–100 km away were used, along with regridded historical data, reanalysis and CMIP6 projections. These revealed increases in temperature, precipitation and humidity, and provided indications of long-term climate pressures at the site. Changing patterns of future precipitation, particularly heavy rain, may threaten the site. The relative humidity changes are small, though an increasing Scheffer index suggests potentially enhanced wood decay. Changes in soil moisture have the potential to disrupt the foundations. Very hot days may become a problem for the two annual celebrations at the site. [ABSTRACT FROM AUTHOR]

A new tetraploid bramble species, Rubus atroroseus, classified within the subgenus Rubus, section Corylifolii, series Sepincola, is described. It is a regional species endemic to north-western Bohemia. It has been recorded at ca 70 localities and the distance between the most remote localities is ca 60 km. It grows most frequently in open and sunny habitats such as roadside ditches, open scrub and fringes of meadows, scrub, and woodlands. The morphological variability of the species is low and indicates apomixis as the probable dominant mode of its reproduction. Rubus atroroseus differs distinctly from all related species known from the Czech Republic and adjacent Germany by the following characters: primocanes pruinose, intensively suffused dark brown-red (in sunlit sites), sparsely hairy and glandular, primocane leaves deep green above, terminal leaflet of primocane leaves usually round with a double serrate margin, pedicels with usually 1–2 prickles, and petals deep pink. A distribution map, a list of revised herbarium specimens, a photograph of the type specimen, a pen drawing and in situ photographs of the species are provided. [ABSTRACT FROM AUTHOR]

Understanding temporal variation in mechanisms and factors shaping metacommunity is an important issue of community ecology. The relative importance of different assembly mechanisms, such as dispersal and environmental filtering, can vary through time in dynamic systems, whereas it is still unclear how different dispersal modes affect temporal patterns of the variation. We investigated metacommunity structures of fish and aquatic insects with flying adults in spring, summer, and autumn in drainage ditches of paddy fields in the Kita River basin, Japan, where agricultural water management and flood events cause seasonal flow changes. Using redundancy analysis and variation partitioning, we examined how the variation of these metacommunity structures was explained by local environmental factors and two types of spatial factors (overland based and watercourse based). Fish metacommunities were mainly influenced by local environmental factors (e.g., water depth) in summer, and by watercourse‐based spatial factors (e.g., distance to downstream rivers) in spring and autumn. As fishes are obligate aquatic dispersers, increased hydrological connectivity among habitats in summer weakens the dispersal limitation from downstream rivers and enables species to track environmentally preferred habitats. In contrast, only overland‐based spatial factors (e.g., spatial patterns based on overland distance) significantly affected aquatic insect metacommunities in summer and autumn. These results suggest that regional and landscape variables can influence their metacommunity patterns more than the local environment. We conclude that the dynamic nature of the environment and dispersal modes can interactively influence metacommunity structures in temporally connecting habitats. [ABSTRACT FROM AUTHOR]

Copyright of Bylye Gody is the property of Cherkas Global University Press 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.)

Copyright of Vadose Zone Journal is the property of Wiley-Blackwell 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.)

Spray drift of glyphosate has the potential to affect non-target vegetation and surface waters close to the application area. To assess the likelihood of such impact along Swedish railways, four field experiments were conducted at three railway sites during 2019 and 2020. An herbicide spraying train applied herbicide Roundup Ultra (glyphosate) at speeds of 33 to 48 km/h. Quantitative filter papers were placed at 0.5, 1, 1.5, 2, 3 and 5 m distances to capture spray droplets. Wind speeds were low (0-2 m/s), but were found to be representative of normal operating conditions. Spray deposition decreased rapidly with distance, declining from 1800 g a.e./ha to an average of 5 g/ha within 1 m. Predicted 90th percentile drift rates suggested potential impact on vegetation within distances <1 m, where 90th percentile spray deposition would range from full dose to 18 g/ha. Beyond 1.5 m from the sprayed area, impact on vegetation was deemed unlikely. The potential concentrations in ditches near railways did not exceed the 100 μg glyphosate/L environmental quality standard even for ditches situated only 0.5 m from the sprayed area, indicating low risk to ditches or final recipients. Actual impact on vegetation was assessed using weed coverage data recorded by the herbicide spraying train itself. We extracted average weed coverages for 10 m sections around the edges of no spray zones and focused on the outermost sections surveyed, 0.35 to 1.4 m outside the application area. Predicted 90th percentile glyphosate deposition ranged from 565 to 6 g/ha, averaging 80 g/ha in this zone. By comparing no spray zones to adjacent track sections, and tracks treated with glyphosate in 2019 to those that were not, we demonstrate that there is a statistically significant but relatively minor effect of spray drift on non-target vegetation close to the track., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Harald Cederlund reports financial support was provided by Swedish Transport Administration. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

This article presents the current state of research on the Early Neolithic settlement enclosures in the Eastern Balkans (ca. 6200/6000–5500 cal. BC), with a focus set on the ditch-digging practices. A large database was accumulated in the last decade during surface surveys, large-scale excavations, and geomagnetic prospection, demonstrating conclusively that ditch enclosures were indeed a tradition rather than an exception. In the Eastern Balkans, enclosures consist mostly of single or multiple ditches and rarely a combination of ditch and wooden, emplectum, or a stone wall. Moreover, some sites existed long enough that the development of the settlement pattern demanded also changes in the enclosures’ layout and/or design. Most of the settlements were enclosed as early as their initial stages. However, no enclosure features have been identified at the earliest Neolithic sites in the area even though this might reflect biased research strategies.

Draining and extracting peat alters a peatland's control of CO2 and CH4 emissions. Carbon (C) emissions from peatlands undergoing extraction are not well constrained due to a lack of measurements. We determine the effect that production duration (years of extraction) has on the CO2 and CH4 emissions from an actively extracted peatland over three years of measurements (2018-2020). We studied five sectors identified by the year when extraction began (1987, 2007, 2010, 2013, 2016). Higher average CO2 and CH4 emissions were measured from the drainage ditches (CO2: 2.05 ± 0.12 g C m-2 d-1; CH4: 72.0 ± 18.0 mg C m-2 d-1) compared to the field surface (CO2: 0.9 ± 0.06 g C m-2 d-1; CH4: 9.2 ± 4.0 mg C m-2 d-1 regardless of sector. For peat fields, CO2 fluxes were highest in the youngest sector, which opened in 2016 (1.5 ± 0.2 g C m-2 d-1). The four older sectors all had similar mean CO2 fluxes (~0.65 g C m-2 d-1) that were statistically different from the mean 2016 CO2 flux. A spatial effect on CO2 fluxes was observed solely within the 2016 sector, where CO2 emissions were highest from the centre of the peat field and declined towards the drainage ditches. These observations occur due to operators' surface contouring to facilitate drainage. The domed shape and subsequent peat removal resulted in a difference in surface peat age hence different humification and lability. 14C dating confirmed that the remaining peat contained within the 2016 sector was younger than peat within the 2007 sector and that peat age is younger toward the centre of the field in both sectors. Humification indices derived from mid-infrared spectrometry (MIRS) (1630/1090 cm-1) indicated that peat humification increases with increasing years of extraction. Laboratory incubation experiments showed that CO2 production potentials of surface peat samples from the 2016 sector increased toward the centre of the field and were higher than for samples taken from the 1987 and 2007 sectors. Our results indicate that peatlands under extraction are a net source of C where emissions are high in the first few years after opening a field for extraction and then decline to about half the initial value and remain at this level for several decades, and the ditches remain a 2 to 3 times greater source than the fields, but represent < 7% of the total area of a field. [ABSTRACT FROM AUTHOR]

One of the major current ecological challenges is to understand how to reconcile human activities with biodiversity conservation concerns. This issue is particularly relevant in freshwater ecosystems where biodiversity is globally under severe threat. Artificial waterbodies, such as ditch networks, are part of the few remaining wetlands in agricultural landscapes and hence play a crucial role in maintaining aquatic biodiversity in these landscapes.We investigated the responses of adult Odonata assemblages at different spatial scales in a marshland crossed by ditches to two factors expected to be pivotal influences on assemblages. At the local scale, this was mainly the water regime in ditches and, at a broader scale, the composition of the landscape. Both taxonomic alpha and beta diversity, and functional trait composition were considered as response variables.Significant differences were found between the responses of the two Odonata suborders. We showed that Zygoptera species richness decreased and species turnover increased with the duration of drying episodes in ditches. Geographical distances between local assemblages as well as landscape characteristics, notably woodland cover, meadow cover and ditch network length, also significantly shaped the distribution of Zygoptera. For Anisoptera, species richness was not explained by environmental variables and beta diversity was associated only with local conditions; it increased with increasing dissimilarity in water quality and riparian vegetation. We also found evidence of functional trait syndromes (combinations of correlated traits) in Odonata assemblages, but without clear relationships to environmental gradients.This study reveals the structuring role of water regime for Odonata in ditch networks and demonstrates the need to jointly consider environmental variables at different spatial scales to properly understand the distribution of Odonata.Our findings have important conservation implications as the water regime is heavily managed in such ecosystems. Even though the relationship between functional composition and environmental gradients was found to be of limited extent in this study, we discuss how it might provide new insights for Odonata assemblage structure and be useful, locally, for stakeholders and managers. Lastly, we call for further multiscale investigations considering both the taxonomic and functional responses of Odonata assemblages (functional analyses with multiple traits and several species being scarce in this taxonomic group) in other anthropogenic freshwater ecosystems to gather more lessons for their conservation. [ABSTRACT FROM AUTHOR]

Crystal blockages of tunnel drainage systems severely undermine the tunnel lining structure and operation safety. In order to reduce the risk of crystal blockages of tunnel drainage systems, the distribution of highway tunnel defects was identified through a field survey, indoor test, and literature analysis, and an optimization method of tunnel drainage structures was proposed. The research suggested the following: (1) Lining water leakage and construction joint water leakage were the most common defects in the tunnel drainage system of Renhua–Xinfeng Expressway and Yingde–Huaiji Expressway in Guangdong Province, accounting for 60% and 32% of total defects, respectively. The number of defects that occurred in the drainage system of the tunnel was larger in the granite formation, with the number of road seepage and inspection chamber crystallization incidents reaching 2.5/km and 2.8/km, respectively. (2) The groundwater was mainly alkaline with a pH value of 8~12, Ca2+ (107 mg/L) was the cation with the largest ion concentration, and HCO3− (165 mg/L) was the anion with the largest ion concentration. The crystals in the tunnel drainage system were predominantly square, spindle, and rhombic calcite and aragonite composed of CaCO3, mixed with a small amount of sediment. (3) To reduce the risk of crystal blockages of the tunnel drainage system and ensure tunnel lining structure safety, a threefold optimization measure was proposed, namely, setting one-directional drainage pipes between the cable trench and the roadside blind drainage ditch, applying "π" type anti-crystallization drainage water-stop belts at the circular construction joints in the secondary lining, and both increasing the slope of the transverse drainage pipe and using an anti-crystallization drainage pipe. The research results will play an important role in guiding the design, construction, and maintenance of highway tunnel drainage systems in China. [ABSTRACT FROM AUTHOR]

Large‐scale, intensive agriculture is a critical activity supporting global food production, yet it has taken a significant toll on the equally critical ecosystem services supplied by global biodiversity. This is particularly true for the planet's most threatened ecosystems: freshwaters. As one of the world's largest agricultural producers, Canada is also home to much of the world's freshwater. As Canada's agricultural capacity expands under climate warming into more northerly latitudes—and in some cases regions with large carbon sinks—it is imperative that this sectoral shift is accompanied by careful management to avoid exacerbating ecosystem service losses. Across Canada, agricultural practices vary in terms of their impact on freshwater ecosystems. Agricultural water extraction, storage behind dams, diversions, dredging and clearing of riparian vegetation can impact more naturalized flow regimes. This review explores the influence of managed low flows on ecosystem functioning in man‐made drainage/irrigation ditch systems. We examine how low flows in these systems can impact ecosystem functions in agricultural watersheds with fragmented natural capital. We provide management options to protect ecosystem functions under a changing climate, recognizing that in agro‐ecosystems, drainage/irrigation ditch systems provide a critical remnant habitat to support biodiversity in otherwise depauperate landscapes. [ABSTRACT FROM AUTHOR]

Copyright of Geopolitica(s): Revista de Estudios Sobre Espacio y Poder is the property of Universidad Complutense de Madrid 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.)

This paper presents the steps performed for the execution of hydrographic works on the Danube - Black Sea Canal (CDMN) and the White Gate - Midia Năvodari Canal (CPAMN), next to Constanţa harbour. These landmarks represent the elemental key of navigation on the Danube River. The general condition of the navigable channels has not been affected since they were put into use, there are a number of problems related to the stability and local integrity of the banks that can endanger the safety of navigation. The purpose of hydrographic studies is to collect, through systematic surveys in navigable areas, georeferenced data related to: bathymetry in the area of interest; classification and precise positioning of underwater contacts; the profile and characteristics of the submerged relief; the volume of alluvium deposited in the canal ditch and their nature; currents and water levels or the physical properties of the water column. [ABSTRACT FROM AUTHOR]

Anurans are a diverse group of vertebrates that occur in several different habitats. Male anurans regularly clasp their conspecific females in their habitats and on different substrates. [Extracted from the article]

The Baligówka peat bog is one of the peat bogs of the Orawa-Nowy Targ Basin—the largest complex of wetlands in the Polish Carpathians. Its area has declined in the past as a result of drainage and peat exploitation, which caused a bad hydrological condition and it is gradually overgrown by non-peat bog medium and high vegetation. The research uses models derived from airborne laser scanning (ALS) and an orthophotomap to delimit the bog and divide it into parts and assess the range of drainage ditches and vegetation. The area of the peat dome along with 3 sites of peat exploitation is currently 159.6 ha, while the ecotone zone is 105.9 ha. Both sections are separated by a steep post-mining slope. The medium and high vegetation areas cover 44% of the peat bog; its location is related to the dense drainage system in the southern part of the dome. The parameters of the Baligówka peat bog: area, size and extent of drainage system, and the degree of overgrowth by high vegetation, are the subject of research towards the protection under the Natura 2000 network (PLH120016) and the establishment of a plan for restoration activities. [ABSTRACT FROM AUTHOR]

Mosquito larval surveys were conducted in two urban neigbourhoods, Surulere and Apapa, in Lagos State, Nigeria from July to October 2021. The aim was to investigate mosquito species composition and habitats utilized by these species with the overall goal of generating useful information to guide mosquito surveillance and control activities targeting vector species. Immature mosquitoes (larva and pupa) found were collected using dipping technique and emerged adults were identified using standard morphological keys. Mosquito abundance, diversity and habitat types were also assessed. A total of 2,696 immature mosquitoes were collected from both areas with 90.3% (2,434) collected from Surulere. Three species of mosquitoes; Aedes aegypti, Culex pipiens complex and Anopheles gambiae complex were found in both Surulere and Apapa. One species identified as Lutzia tigripes was found only in Apapa. In Surulere, Cx. pipiens complex had significantly (p < 0.05) the highest relative abundance (59.8%) while An. gambiae complex had the lowest (2.2%). In Apapa, Ae. aegypti had the highest abundance (68.7%) while Lt. tigripes had the lowest (6.9%) but there was no significant difference. Habitat types encountered in both areas included gutters (roadside ditches), ground pools and man-made containers especially used tyres. Larval densities varied significantly (p < 0.05) among species, and habitat types in Surulere but not in Apapa. The observed variations in species composition and abundance between the two urban neigbourhoods suggest different risk for specific mosquito-borne diseases. Integrated vector management tactics such as source reduction through larval habitat elimination and larviciding are recommended. [ABSTRACT FROM AUTHOR]

Malaria is a widespread vector-borne disease in the tropics and subtropics causing nearly half a million deaths every year. Malaria vector control intervention mainly rely on the control of adults using Indoor residual sprayings (IRS) and long lasting insecticidal nets (LLINs). The purpose of this study was to assess the species composition of Anopheles mosquitoes and determine the environmental and physicochemical parameters of their breeding habitats in Bambasi district, Benshangul Gumuz regional state, northwestern Ethiopia. Three major Anopheles breeding habitats were identified in three Kebeles namely; drainage ditch (Keshmando), swamp (Amba 46), and stagnant water (Amba 47). Anopheles mosquito larvae were sampled twice a month from September 2020 to November 2020. A total of 2185 Anopheles mosquito larvae were collected. Of those collected larvae three Anopheles species (Anopheles gambiae s.l. An. funestus and An. coustani complex) were identified. Anopheles gambiae s.l was the most abundant whereas An. funestus and An. coustani were the least in all the study kebeles. Of the three kebeles, Amba 47 was found the most productive for Anopheles followed by Amba 46 and Keshmando. The highest mean density of larvae per dip was sampled in September in all the study sites. The three sampling sites varied in physicochemical characteristics. The findings of this study showed that dissolved oxygen (DO) was highest (7.07 ± 0.55 mg/L) in the swamps and lowest (0.32 ± 0.04 mg/L) in the drainage ditches. Conductivity across different habitats showed wide variations. There were slight variations in temperature between different habitats. Higher total dissolved solids (TDS) 12.19 ± 0.26 mg/L was recorded from the drainage ditches; whereas TDS 9.49 ± 1.62 mg/L was recorded from the swamp. Salinity in the drainage ditches and stagnant water was 5.54 ± 1.00PSU and 3.30 ± 0.97 PSU respectively. There were negative strong correlation between the larval density with temperature and EC but positive correlation between larval density with salinity. However, there was no significant correlation between Anopheles larval density with TDS and DO. In conclusion this study suggested that environmental and physicochemical factors could play an important role in the development of mosquito larvae. Therefore, characterizing mosquito larval habitats is important for targeted control of malaria vectors in Ethiopia. [ABSTRACT FROM AUTHOR]

Middle Neolithic circular enclosures, known as Kreisgrabenanlage (KGA), are the oldest known monumental sites in Central Europe, dating roughly to 4850–4600/4500 BC. These large prehistoric monuments are mainly discovered by aerial archaeology and have been investigated by geophysical prospection and archaeological excavations since the 1960s. The site of Velm (Lower Austria) was discovered by aerial photographs in 2001. Due to its unusual location on a flat gravel plateau, the enclosure has become the object of intensive interdisciplinary research in recent years. In 2016, two motorized ground-penetrating radar (GPR) surveys were conducted, resulting in a detailed three-dimensional dataset visualizing the circular ditches, palisades and dwellings of an adjacent settlement. The high contrast between the gravel sediments and the humic earthen backfill of the ditches, palisades and individual postholes resulted in a highly detailed visualization of the Middle Neolithic monument. Based on this survey, selected structures were investigated by targeted archaeological excavations to evaluate the GPR results and to take samples for radiocarbon dating. This paper presents a synopsis of all the methods used. An integrated interpretation of aerial photo information, magnetometry and GPR is conducted, and it is shown to what extent these could be verified by the targeted archaeological excavation. By a detailed analysis of all applied archaeological prospection methods, it is now possible to interpret the monument in its entirety and confirm its dating to the Middle Neolithic Lengyel cultural complex. [ABSTRACT FROM AUTHOR]

A one‐dimensional longitudinal mixing model for an oxidation ditch with a moving symmetrical boundary and a series model for a symmetric aeration mixing unit of an aeration tank were developed in this study to analyze their mixing processes. The analysis of these models showed that the mixing process in the oxidation ditch tended to that of a continuous stirred tank reactor (CSTR) in a mode of circulation flow and dispersion; however, the mixing in the aeration tank tended to that of a CSTR in a mode of dispersion. The tracer output patterns and complete mixing times of the oxidation ditch and aeration tank with treatment capacities of 1000–50,000 m3/d and hydraulic retention time 12.0 h were evaluated. The complete mixing time increased from 7.5 min to 128.5 min for the aeration tank with an increase in volume; and the oxidation ditch with same complete mixing time as that of the aeration tank was obtained. The complete mixing time for the oxidation ditch can be changed in a wider range, for matching the time scale of biochemical degradation of organic pollutants. Practitioner Points: Mixing model of an oxidation ditch and an aeration tank were built.Mixing in oxidation ditch tends to that of CSTR in a mode of circulation flow and dispersion.Mixing in an aeration tank is in accordance with advection diffusion and tends to that of CSTR as its Peclet number is large.Complete mixing time for an oxidation ditch can be changed in a wider range. [ABSTRACT FROM AUTHOR]

While many communications media, such as wireless and certain classes of wireline channels, typically lead to bursty errors, most decoders are designed assuming memoryless channels. Consequently, communication systems generally rely on interleaving over tens of thousands of bits to match decoder assumptions. Even for short high rate codes, awaiting sufficient data in interleaving and de-interleaving is a significant source of unwanted latency. We construct an extension to the recently proposed Guessing Random Additive Noise Decoding (GRAND) algorithm, which we call GRAND-MO for GRAND Markov Order. By foregoing interleaving and instead making use of the bursty nature of noise, low-latency communication is possible with block error rates outperforming their interleaved counterparts by a substantial margin. We establish that certain well-known binary codes with structured code-word patterns are ill-suited for use in bursty channels, but Random Linear Codes (RLCs) prove robust to correlated noise. We further demonstrate that by operating directly on modulated symbols rather than de-mapped bits, GRAND-MO achieves further performance and complexity gains by exploiting information that is lost in demodulation. As a result, GRAND-MO provides one potential solution for applications that require ultra-reliable low latency communication. [ABSTRACT FROM AUTHOR]

Nitrogen loss with the farmland drainage from the rice irrigation areas has been a great threat to the aquatic environment of the receiving water in southern China. In this present study, a systematic investigation was made to clarify the effect of different irrigation and drainage control strategies at the field level on ammonia nitrogen (NH3-N) reduction. The potential of pollutant reduction with the ditches and ponds was also proposed to meet the requirements of water quality in small agricultural watersheds. A case study was set in the Yanyun Irrigation Area along the Grand Canal in Yangzhou City, Jiangsu Province, China. A field experiment was performed on rice irrigation and drainage in two rice growing seasons. Some parameters were measured, including the soil properties, groundwater depth, and nitrogen concentrations of drainage flow in the field. The field hydrological model-DRAINMOD was used to simulate the different water management scenarios. A conceptual model was developed to predict the nitrogen reduction in the ditches and ponds under different irrigation and drainage management scenarios. The results showed that the annual drainage depth was as high as 1 162 mm, accounting for 59% of the total irrigation and rainfall depth under the current irrigation and drainage practice. The surface runoff depth accounted for 51% of the total drainage, including a 20% uncontrollable portion caused by storm events. A controlled irrigation strategy (or irrigating only when the field water level drops to -25 cm and no significant rainfall was forecasted) was significantly adopted to reduce the drainage and nitrogen losses: 55% reduction in the drainage and 59% reduction in the NH3-N, compared with the conventional practice. However, the controlled drainage presented a relatively low effect on drainage reduction and surface runoff. The total drainage remained nearly constant for the controlled drainage with the fixed irrigation volume under the current irrigation practice, indicating an increase in the surface runoff from 51% to 75%. The total drainage was reduced from 519 mm to 435 mm (16% reduction), whereas, the surface runoff increased from 35% to 56% under the controlled irrigation practice. The NH3-N concentration in the surface runoff (2.85 mg/L) was higher than that in the subsurface drainage (1.80 mg/L), indicating the significant increase of NH3-N losses with the increased surface runoff. Therefore, there were much higher volumes of irrigation and drainage water in the nitrogen reduction, in terms of the ditches and ponds distribution in the small agricultural watershed of the study area. Only when the drainage volume was significantly reduced using the controlled irrigation and drainage practice, the current ditches and ponds (15% of the farmland area) can be expected to gain lower ammonia nitrogen concentration level for the national water quality standards of Class V for surface water. Nevertheless, there is also an adverse impact on the NH3-N for the shallow depth (60 cm) of the drainage ditches, due to the increase in the surface runoff in the study area. In conclusion, the controlled irrigation of paddy fields can be more effective to reduce drainage and nitrogen losses. Consequently, the reduced amount of drainage water and the integrated management or optimization of the existing wetlands of ditches and ponds can greatly contribute to the water quality of rice irrigation areas in small agricultural watersheds. [ABSTRACT FROM AUTHOR]

Copyright of Railway Signalling & Communication Engineering is the property of Railway Signalling & Communication Engineering 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.)

Copyright of Coal Science & Technology (0253-2336) is the property of Coal Science & Technology 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.)

Ditch cleaning (DC) is increasingly applied to facilitate forest regeneration following clear-cutting in Fennoscandinavia. However, its impact on the ecosystem carbon and greenhouse gas (GHG) balances is poorly understood. We conducted chamber measurements to assess the initial DC effects on carbon dioxide (CO2) and methane (CH4) fluxes in a recent forest clear-cut on wet mineral soil in boreal Sweden. Measurements were conducted in two adjacent areas over two pre-treatments (2018/19) and two years (2020/21) after conducting DC in one area. We further assessed the spatial variation of fluxes at three distances (4, 20, 40 m) from ditches. We found that DC lowered the water table level by 12 ± 2 cm (mean ± standard error) and topsoil moisture by 0.12 ± 0.01 m3 m−3. DC had a limited initial effect on the net CO2 exchange and its component fluxes. CH4 emissions were low during the dry pre-treatment years but increased particularly in the control area during the wet years of 2020/21. Distance to ditch had no consistent effects on CO2 and CH4 fluxes. Model extrapolations suggest that annual carbon emissions decreased over the four years from 6.7 ± 1.4 to 1.6 ± 1.6 t-C ha−1 year−1, without treatment differences. Annual CH4 emissions contributed <2.5% to the carbon balance but constituted 39% of the GHG balance in the control area during 2021. Overall, our study suggests that DC modified the internal carbon cycling but without significant impact on the carbon and GHG balances. [ABSTRACT FROM AUTHOR]

Agricultural intensification is debated as one of the major drivers for the decline of insect biodiversity. Agri-environmental schemes (AES) are a common measure to promote biodiversity in agriculture by granting compensational payments to farmers for environmentally friendly practices. In this study we examined the effect of buffer strips of at least 5 m width, adjacent to small watercourses and drainage ditches, on insect biomass and insect species richness in agricultural landscapes. We selected ten arable fields in each of four regions in lower and upper Bavaria, Southern Germany. 25 out of 40 sites had a buffer strip between arable crops and watercourse. Insects were sampled at three time periods (May/June, June/July and August/September) for two weeks each. In each period two samples were collected (one per week). On each site Malaise traps were set up in 5 and 80 m distance to the embankment of the watercourse. Half of the samples was then subjected to metabarcoding and the other half was classified into different insect groups by morphological identification and the number of the individuals for each group was counted. For hoverflies (Syrphidae), individuals were identified at species-level. Data on vegetation structure (cover of grasses and herbs) in the studied riparian buffer strips was collected and correlated with number of species, abundances and biomass of flying insects. The five taxonomic orders with the highest species richness and individual numbers were: Diptera, Hymenoptera, Coleoptera, Lepidoptera and Hemiptera. Diptera dominated hereby with 34% of all species and 81% of all individuals. On average, mixed models indicated 31% higher insect biomass, 15% higher species richness and 29% higher individual numbers of flying insects in buffer strips at 5 m distance to the watercourse compared to sites with no buffer strip. The effect was even stronger for butterflies (32% higher species species richness, 70% more individuals) and hoverflies (24% higher species richness, 51% more individuals). In the presence of a buffer strip significantly higher numbers were found for total individuals, Diptera, Hymenoptera and Coleoptera. In 80 m distance to the watercourse, the samples of flying insects were not significantly influenced by a riparian buffer strip. This study highlights the importance of buffer strips in agricultural regions and their multifunctional potential in fostering biodiversity additionally to their acknowledged use for water protection. Ideally, buffer strips are rich in herbs and inflorescences and are therefore beneficial for the insect fauna by serving as valuable habitat with high potential connectivity at landscape level. • 31% higher biomass on average of flying insects in riparian buffer strips compared to agriculturally used fields. • 15% higher species richness on average of flying insects in riparian buffer strips compared to agriculturally used fields. • 29% higher individual numbers on average of flying insects in riparian buffer strips compared to agriculturally used fields. [ABSTRACT FROM AUTHOR]