Stream Structure Research Articles

Brown trout density effects on the macroinvertebrate and biofilm communities of headwater streams: a cage experiment

Salmo trutta is a key species of headwater streams that is able to influence the structure of these ecosystems through predation. Populations of this species are being threatened by climate change and hydrological alteration. In order to understand how their disappearance would affect the ecosystem structure of headwater streams, we used cage experiments to analyse different biofilm and macroinvertebrate structural parameters and the biodiversity of their communities under different trout densities. Due to a heavy rain event, our experiment was destroyed on the 10th day, but the role of trout as stream ecosystemic structure drivers was observed, as multiple parameters were modulated by their presence or absence. In the high-density treatments, a significant reduction in the biomass of macroinvertebrate families that fed on biofilms was observed due to direct predation on them, which caused the biofilms to be more autotrophic. A decrease in brown trout population densities could cause cascading trophic effects on the ecosystem structure of headwater streams

USE OF THE RESULTS OF THE WORK OF THE UKRAINIAN METEOR NETWORK IN THE PROCESS OF TEACHING PHYSICS TO STUDENTS OF THE EDUCATIONAL AND SCIENTIFIC INSTITUTE OF ENERGY, AUTOMATION AND ENERGY SAVING NULES OF UKRAINE

Features of meteor fixation methods are presented by organizing a network of corresponding observation points - permanently operating observation stations located on the territory of Ukraine with appropriate technical and software support for conducting basic and one-way observations of meteors in the radio range of electromagnetic wavelengths. This contributes to solving the strategic problems of meteor research, the structure and evolution of meteor showers and streams, the interaction of meteoroids with the Earth's atmosphere and their chemical composition. Scientific and technical products of observation stations are the results of high-precision basic or one-sided observations of meteors in the radio range of electromagnetic wavelengths, fundamental and applied scientific and technical research. The purpose of the study is to consider the principle of operation of the Ukrainian meteor observation network, a separate meteor hardware and software complex for observing meteors in the radio range of electromagnetic waves using the method of direct scattering on meteor trails of signals from powerful FM radio broadcasting stations with the possibility of further processing and presentation of data by students of specialties 141 "Electric power, electrical engineering and electromechanics", 144 "Thermal power engineering", 174 "Automation, computer-integrated technologies and robotics" of the Educational and Scientific Institute of Energy, Automation and Energy Saving of NULES of Ukraine in the process of studying physics. Processing of experimental data was carried out by students of the specified specialties under the guidance of the author while studying physics. The results of statistical data processing of meteor invasions and their graphic representation by students of the specified specialties in the process of mastering physics are described. Prospects - putting into operation by the end of 2024 the seventh receiving station in the city of Kyiv (student campus of NULES of Ukraine) - the seventh meteor hardware and software complex, as a component of the Ukrainian meteor observation network.

Steam structure and thermal conductivity of lightweight concrete aggregate

The article describes the results of theoretical and experimental studies to identify the relationship between the parameters of the steam structure and thermal conductivity of ashclaydite. The correlation dependences of the thermal conductivity coefficient of ash-claydite on its parameters of the stream structure have been established. The analysis of these works shows that the thermal conductivity of lightweight concrete depends on the type of porous aggregate, on the direction of the heat flow in relation to the layering of the concrete, the average temperature at which heat transfer occurs, the average density and moisture content of the concrete. In most works, a significant effect of the steam structure of the aggregate on the thermal conductivity of concrete is noted.

Interactions between Urban Stream Structure and Waterbird Community Composition

Interactions between Urban Stream Structure and Waterbird Community Composition

XML Query Optimization for Improvement of Data Warehouses Information Processing

XML data warehouses give decision-support systems a chance to use complicated data by giving them a place to start. But native-XML database management systems are slow right now, so it is important to look into ways to make them faster. This study presents two strategies to think about. To start, we suggest using a link index that was made with the fact that XML warehouses have a lot of dimensions in mind. The join procedures are taken out, but the data from the first warehouse stays the same. Second, we show how to choose XML materialized views by grouping the query load to show how this can be done. To prove that these ideas work, we built a set of decision support XQuery tools and ran them against an XML data warehouse. We compared the results obtained with and without our optimization methods. Our tests show that it works, even though the queries themselves are a little hard to understand and the datasets themselves are very big. XML has emerged as the widely accepted standard for transmitting data over mobile wireless networks. In these kinds of networks, mobile clients can use a wireless broadcast channel to send queries to get the XML data they need. Because mobile devices are so small and have so little storage space and a short battery life, it may be hard for customers to download the whole XML data set on one of these devices. To solve this problem, you need to index XML data so that mobile clients only have to download the parts of the file they need. Users who want to access only certain parts of the XML content in an XML stream could use one of several indexing methods. Still, the indexing methods that are used now add more data to an XML stream that is already very large. This research comes up with a new XML stream structure for broadcasting XML data by compressing and summarizing the information about how XML nodes are put together. This study was conducted in the United Kingdom. When data is summed up before being sent, the time it takes to get it in XML format over a wireless broadcast channel can be cut down. The recommended XML stream structure also has indexes that will help you skip over any data that is not important. So, it could make it less likely that XML query results will drain the batteries of mobile devices when they are being processed. We also found that our suggested XML stream design was better than its predecessors in terms of access and tuning times for processing XML queries over the XML data stream. So, our architecture can be used to answer a wide range of XML questions.

Bibliometric review on human resources management and big data analytics

PurposeThis study aims to provide an in-depth understanding of big data analytics (BDA) in human resource management (HRM). The emergence of digital technology and the availability of large volume, high velocity and a great variety of data has forced the HRM to adopt the BDA in managing the workforce.Design/methodology/approachThis paper evaluates the past, present and future trends of HRM through the bibliometric analysis of citation, co-citation and co-word analysis.FindingsFindings from the analysis present significant research clusters that imply the knowledge structure and mapping of research streams in HRM. Challenges in BDA application and firm performances appear in all three bibliometric analyses, indicating this subject’s past, current and future trends in HRM.Practical implicationsImplications on the HRM landscape include fostering a data-driven culture in the workplace to reap the potential benefits of BDA. Firms must strategically adapt BDA as a change management initiative to transform the traditional way of managing the workforce toward adapting BDA as analytical tool in HRM decision-making.Originality/valueThis study presents past, present and future trends in BDA knowledge structure in human resources management.

Pool Formation and The Role Of Instream Wood In Small Streams In Predominantly Second-growth Forests.

Extensive and intensive forest harvesting during the 20th century often had, and continues to have, negative impacts on stream structure and ultimately fish. Loss of instream wood and pools has been identified as a pathway by which riparian forest management can negatively impacts salmonids. Passive riparian restoration (allowing forests and streams to recover through natural processes) through the use of riparian buffers when conducting forest harvests has often been employed to promote stream habitat recovery. In this study, we evaluate the effects of 25 years of passive restoration on instream wood and pool recovery in 74 reaches in small streams (1st through 3rd order) across three channel types (pool-riffle, step-pool, and cascade) in a predominantly second-growth forest. Gradient and stream size were the most important variables for determining pool density, while stream size was the most important variable for determining pool depth. Instream wood formed 39% of pools in pool-riffle, 30% of pools in step-pool and 25% of pools in cascade channels types. Instream wood volume had a significant (R2 = 0.261, P ≤ 0.001) positive relationship with pool volume in wood-formed pools. Dimensions of individual wood pieces were associated with their likelihood of pool formation: for each additional 1 meter length within the bankfull channel the odds of forming a pool increased by 25.6%, and for each additional centimeter in diameter the odds of pool formation increased by 2.0%. When compared with studies conducted in both second- and old-growth forests, we concluded that streams associated with second-growth forests hadve both reduced densities and sizes of instream wood and pools. Young forests are likely continuing to negatively impact stream habitat and fish populations. Because riparian zones in many forests are now dominated by relatively young forest stands, and given the timeline for recovery using passive restoration alone (e.g., 100 s of years in Pacific Coastal forests), active restoration could be explored to accelerate instream wood and pool recovery.

Addressing phase of population cycle and spatial scale is key to understand vole abundance in crop field margins: Implications for managing a cyclic pest species

In simplified agricultural landscapes, some rodent species such as the common vole (Microtus arvalis) can reach high abundances and become agricultural pests. Crop field margins are a key structural element and, therefore, expected to play a key role in vole abundance, even within the demographic cycles that govern vole population dynamics. Here, we aim to identify i) the margin variables that determine vole population response, and ii) at which spatial scale this response can be identified and, therefore, managed. We sampled vole abundance in field margins in two replicated areas of north-western Spain during five years, including all population phases. Environmental variables related to vegetation structure, nearby crops and presence of streams or ditches were extracted at two different spatial scales: a precise small spatial scale -“trapping point” scale-, which referred to the exact location of the traps, and a broader spatial scale -“margin” scale-, that referred to the average values across the whole margin length. Using linear mixed models, we analysed the effects of the environmental variables at both spatial scales during the vole population cycle phases. The broad spatial scale accounted better for vole abundance response, being the latter dependent on the population cycle phase. The stronger effect of environmental variables consisted on vegetation structure effects during the peak phase. In this phase, margins with high cover and short vegetation promote high vole abundances, whilst margins with less cover and taller vegetation, usually associated with higher stability in margins, were related to lower peak abundances. No clear effect of nearby crops was detected in our models, when all variables were accounted for. Our results suggest that keeping stable and well vegetated field margins leads to lower abundance within crop field margins during the population outbreaks, and that any successful management strategy should be addressed to the full extent of the field margin, instead of more localized actions.

WOOD PREDICTORS IN NEOTROPICAL STREAMS: ASSESSING THE EFFECTS OF REGIONAL AND LOCAL CONTROLS IN AMAZON AND CERRADO CATCHMENTS.

Large wood plays a critical role providing complex habitat structure in rivers and streams. The instream wood regime consists of wood recruitment, transport, retention, and decay in river corridors. In tropical streams, transport and decay are thought to be the dominant influences on the amount instream wood stored, and these are driven by upstream forest cover, as well as catchment hydroclimatic and geomorphic characteristics. Lack of studies of the tropical wood regime leave many uncertainties. Notably, the wood regimes in the neotropical Amazon and Cerrado biomes are not known, and rapidly changing land-use threatens efforts to understand their natural wood regime. We investigated predictors of instream wood in catchments of the Amazon and Cerrado subject to a wide range of agricultural land use to identify the critical factors controlling wood recruitment and load. Using the structural equation modelling technique, we disentangled the complex net of regional and local controls. Contrary to our expectations, local drivers, such as the relation between the piece size and channel dimensions, discharge, stream power and riparian forest were the most important predictors of instream wood. The amounts of wood found in these streams were primarily the result of the wood delivered by the local riparian forest and how much of that wood remains trapped. Therefore, the preservation of the forested riparian zones in Amazon and Cerrado streams is crucial for maintaining the sources of wood as well as the channel morphology capable of trapping and retaining instream wood. Further research should compare reference and disturbed streams to quantify the influence of anthropogenic activities on instream wood and its primary influences. This information would facilitate assessing the extent of human alteration and developing mitigating measures to arrest or reverse changes that reduce instream wood and degrade aquatic and riparian habitat in neotropical rivers and streams.

Connectomics and the neural basis of behaviour.

Methods to acquire and process synaptic-resolution electron-microscopy datasets have progressed very rapidly, allowing production and annotation of larger, more complete connectomes. More accurate neuronal matching techniques are enriching cell type data with gene expression, neuron activity, behaviour and developmental information, providing ways to test hypotheses of circuit function. In a variety of behaviours such as learned and innate olfaction, navigation and sexual behaviour, connectomics has already revealed interconnected modules with a hierarchical structure, recurrence and integration of sensory streams. Comparing individual connectomes to determine which circuit features are robust and which are variable is one key research area; new work in comparative connectomics across development, experience, sex and species will establish strong links between neuronal connectivity and brain function.

Self-Organizing Fuzzy Belief Inference System for Classification

Evolving fuzzy systems (EFSs) are widely known as a powerful tool for streaming data prediction. In this article, a novel zero-order EFS with a unique belief structure is proposed for data stream classification. Thanks to this new belief structure, the proposed model can handle the interclass overlaps in a natural way and better capture the underlying multimodel structure of data streams in the form of prototypes. Utilizing data-driven soft thresholds, the proposed model self-organizes a set of prototype-based <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">if</small> – <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">then</small> fuzzy belief rules from data streams for classification, and its learning outcomes are practically meaningful. With no requirement of prior knowledge in the problem domain, the proposed model is capable of self-determining the appropriate level of granularity for rule-based construction, while enabling users to specify their preferences on the degree of fineness of its knowledge base. Numerical examples demonstrate the superior performance of the proposed model on a wide range of stationary and nonstationary classification benchmark problems.

Eco-hydrological modelling of channel network dynamics-part 1: stochastic simulation of active stream expansion and retraction.

Dynamic changes in the active portion of stream networks represent a phenomenon common to diverse climates and geologic settings. However, mechanistically describing these processes at the relevant spatiotemporal scales without huge computational burdens remains challenging. Here, we present a novel stochastic framework for the effective simulation of channel network dynamics capitalizing on the concept of 'hierarchical structuring of temporary streams'-a general principle to identify the activation/deactivation order of network nodes. The framework allows the long-term description of event-based changes of the river network configuration starting from widely available climatic data (mainly rainfall and evapotranspiration). Our results indicate that climate strongly controls temporal variations of the active length, influencing not only the preferential configuration of the active channels but also the speed of network retraction during drying. Moreover, we observed that-while the statistics of wet length are mainly dictated by the underlying climatic conditions-the spatial patterns of active reaches and the size of the largest connected patch of the network are strongly controlled by the spatial correlation of local persistency. The proposed framework provides a robust mathematical set-up for analysing the multi-faceted ecological legacies of channel network dynamics, as discussed in a companion paper.

One-shot many-to-many facial reenactment using Bi-Layer Graph Convolutional Networks

Facial reenactment is aimed at animating a source face image into a new place using a driving facial picture. In a few shot scenarios, the present strategies are designed with one or more identities or identity-sustained suffering protection challenges. These current solutions are either developed with one or more identities in mind, or face identity protection issues in one or more shot situations. Multiple pictures from the same entity have been used in previous research to model facial reenactment. In contrast, this paper presents a novel model of one-shot many-to-many facial reenactments that uses only one facial image of a face. The proposed model produces a face that represents the objective representation of the same source identity. The proposed technique can simulate motion from a single image by decomposing an object into two layers. Using bi-layer with Convolutional Neural Network (CNN), we named our model Bi-Layer Graph Convolutional Layers (BGCLN) which utilized to create the latent vector’s optical flow representation. This yields the precise structure and shape of the optical stream. Comprehensive studies suggest that our technique can produce high-quality results and outperform most recent techniques in both qualitative and quantitative data comparisons. Our proposed system can perform facial reenactment at 15 fps, which is approximately real time. Our code is publicly available at https://github.com/usaeed786/BGCLN.

Amphibian loss alters periphyton structure and invertebrate growth in montane streams.

Amphibians are declining worldwide due to a combination of stressors such as climate change, invasive species, habitat loss, pollution and emergent diseases. Although their losses are likely to have important ecological consequences on the structure and functioning of freshwater ecosystems, this issue has been scarcely explored. We conducted an experiment in three montane streams-where primary production is the main source of energy and carbon-to assess the effects of amphibian disappearance (i.e. presence or absence of the common midwife toad Alytes obstetricans, a common species found in pools of these streams) on several aspects of ecosystem functioning and structure: periphyton biomass and chlorophyll a concentration, algal assemblage structure, and growth of macroinvertebrate grazers. We compared four types of experimental enclosures: (i) without macroinvertebrates or amphibians; (ii) with larvae of the caddisfly Allogamus laureatus; (iii) with A. obstetricans tadpoles; and (iv) with both A. laureatus larvae and A. obstetricans tadpoles. The absence of tadpoles increased periphyton biomass, but did not cause differences on inorganic sediment accrual. The algal assemblage had a higher diversity in the absence of tadpoles, and their characteristic taxa differed from the assemblages in presence of tadpoles. A. laureatus presented higher mass in presence of tadpoles; however, tadpole length was not affected by presence of macroinvertebrates. Our results suggest that presence of tadpoles is a driver of periphyton accrual and assemblage structure, acting as top-down control and with key potential consequences on the functioning of montane stream ecosystems.

Speicheranlagen und Wildbäche im Einflussbereich von langsam ablaufenden Großmassenbewegungen

AbstractSlow moving landslides are a common phenomenon in the Alps. Often built‐up areas, infrastructure such as motorways, water storage or stream control structures are affected by such landslides. In this paper two case studies are discussed to present a decision‐making system for the evaluation and handling of such slow‐moving landslides.

Solar Cycle Variability in Coronal Holes and Their Effects on Solar Wind Sources

AbstractVarious upstream spacecraft have now observed the solar wind conditions affecting the Earth since the 1970s, covering over four solar activity cycles. These measurements provide a long term picture of the related patterns in large scale incident plasma and magnetic field parameters of interest for both interpreting cycles in geospace effects, and understanding how the Sun controls our space environment. This paper focuses on the latter, in part to provide context at the start of the new solar cycle 25, and toward establishing connections between the 1 AU ecliptic solar wind behavior and the unprecedented near‐Sun measurements of heliospheric features on Parker Solar Probe and Solar Orbiter. Magnetograph data‐based potential field source surface models provide a basic picture of how the solar wind sources, including those that give rise to corotating high speed streams in the ecliptic, have changed since the beginning of the record of regular solar wind measurements. In particular, they suggest the contributions from low to mid latitude coronal holes dominate the observed cycles (21–24), especially the weaker cycles (23 and 24), impacting upstream measurement interpretations, modeling, and forecasting considerations. For example, recurring features are affected by differential rotation of the Sun's surface field, which through its effects on the corona, can produce solar wind streams reappearing at ∼25–30 days intervals instead of at the canonical 27.3 days Carrington rotation rate. In addition, the conditions that lead to the corotating stream structure that can dominate periods of low solar activity are seen to be more complicated than suggested by the simple concepts of early studies. The overall results illustrate where in the cycles well‐defined, long‐lived large scale structures can be expected, and the advantages of synoptic displays of 1 AU solar wind parameters for anticipating timings of recurring features.

The Adaptive Streaming SAR Back-Projection Algorithm Based on Half-Precision in GPU

The back-projection (BP) algorithm is completely accurate in the imaging principle, but the computational complexity is extremely high. The single-precision arithmetic used in the traditional graphics processing unit (GPU) acceleration scheme has low throughput and its usage of the video memory is large. An adaptive asynchronous streaming scheme for the BP algorithm based on half-precision is proposed in this study, and then it is extended to the fast back-projection (FBP) algorithm. In this scheme, the adaptive loss factors selection strategy ensures the dynamic range of data, the asynchronous streaming structure ensures the efficiency of large scene imaging, and the mixed-precision data processing ensures the imaging quality. The schemes proposed in this paper are compared with BP, FBP, and fast factorized back-projection (FFBP) algorithms of single-precision in GPU. The experimental results show that the two half-precision acceleration schemes in this paper reduce the video memory usage to 74% and 59% of the single-precision schemes with guaranteed image quality. The efficiency improvements of the proposed schemes are almost one and 0.5 times greater than that of the corresponding single-precision scheme, and the advantage can be more obvious when dealing with large computations.

Planning for sustainable rural development through streaming methodology

The purpose of the study was to analyze the rural settlement using streaming maps revealing the features of economic use of the natural-territorial complex. The testing of the streaming methodology is presented on the example of geoecological analysis of Maslovopristansky rural settlement of Belgorod region, which allows to determine the direction and accumulation of surface and groundwater with a high degree of reliability. Streaming maps clearly show information about the connection of the terrain of a rural settlement and its infrastructure (roads, bridges, buildings, underground communications) with elements of nature (groundwater and groundwater, rocks, soils). The method of relief plastics made it possible to assess the geoecological state of the studied territory, which made it possible to identify the streaming structures and systems most favorable for the placement of construction objects.

Provider perceptions of availability, accessibility, and adequacy of health and behavioral services for Latino immigrants in Philadelphia: a qualitative study

ObjectiveLatino populations in the United States are disproportionately affected by substance use, HIV/AIDS, violence, and mental health issues (SAVAME). A growing body of evidence demonstrates the syndemic nature of SAVAME and the need for integrated strategies to reduce their impact. This study sought to understand the network of SAVAME services for Latino immigrants in Philadelphia to inform future interventions for SAVAME prevention and mitigation.MethodologyKey informant interviews (N = 30) were conducted with providers working in Latino-serving organizations providing SAVAME services. Interviews were analyzed using thematic coding and grounded theory.ResultsLatino-serving providers perceived a large need for, and important limitations in the availability, accessibility, and adequacy of SAVAME services for Latino immigrants. Gaps were seen as especially acute for mental health and substance use services, partly because of insufficient funding for these services. Latino immigrants’ lack of health insurance, immigration status, limited English proficiency (LEP), stigma surrounding SAVAME issues, and limited knowledge of available services were identified as significant barriers preventing access to services. Providers noted that scarcity of well-trained, culturally competent, and ethnically concordant providers reduced the adequacy of SAVAME services for Latino immigrant clients. The small size, low levels of infrastructure, and limited capacity were reported as additional factors limiting the ability of many Latino-serving organizations to adopt a syndemic approach in the prevention and treatment of SAVAME services.ConclusionsThe results call for changes in the structure of funding streams and communitywide strategies to foster collaboration across SAVAME providers working with Latino immigrant clients.

Quality culture boosts agile transformation—Action research in a business‐to‐business software business

AbstractAgile methodologies are sometimes adopted, with the assumption that benefits can be attained by only using a set of best practices, which can sometimes work to a degree. In this paper, a case is discussed where a software‐producing organization of seven teams achieved significant improvements. The goal of the research was to answer two questions: how an already agile organization could improve its performance further and what is the impact of promoting quality aspects? The questions were answered by implementing interventions based on prior literature and data emerging from semi‐structured interviews. The context was an established business with a complex revenue stream structure, meaning the mix of various project/service/product based work rendered the adoption of agile methods a challenge. Action research comprising three rounds of interventions was conducted to improve the organization and its quality culture while enforcing code review practices. Interventions resulted in a significant improvement in quality, as measured by reported defects. Therefore, it is suggested that agile methods are not sufficient on their own to take software business forward unless a quality‐focused culture is simultaneously achieved through a mindset change and organizational structures to enforce quality practices. The paper contributes to research on the managerial practices of software business and agile transformation by providing empirical support to introducing formal quality improvement to the agile mix as a method for practitioners to improve organizations with complex business models and multiple teams.