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1
Dolgov, Sergey G. "The Civil Law Liability of Taxi Aggregators." Civil law 1 (February 4, 2021): 3–7. http://dx.doi.org/10.18572/2070-2140-2021-1-3-7.
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Within the framework of this article, an analysis of the points of view of the authors, who in their works touched on the problems associated with the impossibility of bringing taxi aggregators to civil liability, was carried out, it was revealed that the current regulatory legal acts do not contain a direct rule providing for the liability of taxi aggregators, it was concluded that that the absence of legislation at the federal level creates problems for victims who have suffered from the dishonest actions of taxi drivers to receive compensation for the damage to life and health caused by road accidents, an analysis of judicial practice confirming the problem of bringing taxi aggregators to justice.
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Girich, M. G., and A. Saule. "INTERNATIONAL STANDARDS IMPACT ON THE REGULATION OF NATIONAL TAXI AGGREGATOR MARKETS." International Trade and Trade Policy, no. 2 (June 23, 2020): 146–61. http://dx.doi.org/10.21686/2410-7395-2020-2-146-161.
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The development of the sharing economy has affected the change in the passenger transportation market, as online platforms for taxi services have appeared. For example, Uber Technologies plays a significant role in the market, which in 2017 won first place in the top 10 startups of the sharing economy. Currently, there are many problems that arise with the regulation of online taxi platforms. The Organization for Economic Co-operation and Development, together with the International Transport Forum, is conducting a study of the law enforcement practices of countries regarding the regulation of online taxi platforms (or taxi aggregators), in particular, the problems of deploying the online platform for the transport of passengers and baggage by passenger taxi as a regular online platform or as a transport provider, and licensing problems for such online platforms, problems of control over obtaining permission directly by the driver, problems of vehicle safety of control over the drivers, ensure quality of service, traffic security problems and etc.
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Kuchieva, Irina Kh, Zarina Yu Kaloeva, and Sofiya S. Triandofilova. "Marketing Strategy of the Uber Company in the Global Taxi Service Aggregator Market." Vestnik of North-Ossetian State University, no. 4 (December 25, 2021): 170–76. http://dx.doi.org/10.29025/1994-7720-2021-4-170-176.
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The article focuses on the consideration of the marketing strategy of the Uber company. A strategy is essential when a company enters new markets. It is a difficult task for any business and requires managers to understand the specifics of the formation, management of marketing strategies in both local and global markets. The above factors determine the relevance of the research topic. In connection with the processes of globalization and significant modifications in the technological support of business, activities in modern markets are changing significantly. The purpose of this article is to analyse the implementation of the marketing strategy of Uber in the global market to indicate the characteristics and directions of development. In research, the following methods applied: a comparative, analysis and methodology for developing marketing strategies. The American service Uber is striving to gain leadership positions in the development of the Russian market. This drive drives offensive strategies that combine direct competition for low prices and strategies that increase resources and customers by engaging an audience that competitors have missed. As the analysis of the company’s activities showed, Uber implements a specific marketing strategy as an offensive strategy. As part of the confrontation with the main competitors, Uber actively invests in the promotion and advertising of the service, pays attention to pricing policy to provide opportunities for participation in price competition. The American service Uber is striving to gain leadership positions in the development of the Russian market. This commitment drives offensive strategies that combine direct competition for low prices and plans that increase resources and customer base by engaging an audience that competitors have missed. As a result of the analysis of the market of services-aggregators of taxi services, we can conclude that competition is intensifying both from the main competitors, Gett and Yandex.Taxi, and from indirect competitors. Hence, launching a third-party service will be a reactive strategy for Uber, as chief competitors have already diversified their service portfolio. Thus, the marketing strategy in modern conditions of development is an efficient mean for promoting a company in the international market.
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Kuchu, Jayasree. "Spatial temporal pattern analysis on on-demand cab services in urban areas using GIS." IOP Conference Series: Earth and Environmental Science 1086, no. 1 (September 1, 2022): 012031. http://dx.doi.org/10.1088/1755-1315/1086/1/012031.
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Abstract As an important component of the urban public passenger transportation system, cabs / taxi offers an all-weather, convenient, comfortable, and personalized travel services for the urban residents, as well as playing a key role in the urban passenger transportation development. Cab market has gained prominence over last 2-3 years in India, in the backdrop of entry of app based aggregators which has not only disrupted auto-rickshaw and traditional taxi market but also forced automotive Original Equipment Manufacturers (OEMs) to revise their growth and marketing strategies. There is a randomness and lack of regularity of cab operation characteristics, to describe cab travel activity pattern. Inorder to plan and effectively manage on-demand cab services, and to improve better facility to public, there is a need to understand the underlying relationship between supply and demand. This study analyzed the urban cab location distribution characteristics from different temporal and spatial levels. In the time level, the difference with daily location and operation pattern (weekday versus weekends) is identified; in the space level, the cab location pattern over a space are explored. Cab coverage index and Standard deviation ellipse are the tools used in analysing the patterns over time and space frames. This research can be helpful for understanding urban cab behavior pattern, as well as the contribution to the geographical activity space analysis. GIS has been used as a supportive tool in the study
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Iroshnikov, Denis V. "Transport Security in the Sustainable Development of the City: Legal Aspect." E3S Web of Conferences 208 (2020): 05015. http://dx.doi.org/10.1051/e3sconf/202020805015.
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A sustainable city imposes stringent requirements on transport infrastructure. Nowadays the city transport must meet a number of criteria. That means it has to be advanced, environmentally compliant, and safe. Herewith, transport must be safe for a driver and his passengers as well as for other road users (such as pedestrians and others). Recently, alternative modes of transport have become widespread in the cities. This includes personal electric transport: segway, self-balancing scooter, electric scooter, unicycle, etc). Some countries have been already operating autonomous vehicles within the urban traffic whereas in other countries they are undergoing final testing before their release on urban roads. In large cities and metropolises, carsharing service which has already proven its effectiveness is actively developing. The usual modes of city transport are also improving. For instance, the taxi has been almost completely brought under the control of web-aggregators (“Uber” and others). All of that requires thorough scientific research in the sphere of ensuring transport security which is the indispensable condition of the sustainable city concept.
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Waraich, Sushmita Biswal, and Ajay Chaturvedi. "Jugnoo: expansion or consolidation." Emerald Emerging Markets Case Studies 10, no. 1 (January 2, 2020): 1–19. http://dx.doi.org/10.1108/eemcs-09-2018-0201.
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Learning outcomes The student will be able to understand the concept of spotting an opportunity and exploiting the same. The student will be able to comprehend the various challenges faced in the development of a business idea. The student will be able to understand the strategies that need to be adopted to cope with and grow, in a competitive business environment. Case overview/synopsis Samar Singla, the Chief Executive Officer of Jugnoo, had sensed a business opportunity in auto rickshaw aggregation. He was convinced that being among the initial players in the market of auto rickshaw aggregation, there would be very little competition. He only had to play his cards right, to become the top auto aggregator. As Singla started the business, there were challenges like inducting the auto rickshaw drivers as partners, training them, hiring the right team, putting the right strategies in place and to expand the business. Singla launched and achieved robust growth in the new business, in a short period of time. Soon, however, Jugnoo felt competition breathing down their neck – form cab aggregators who were already dominant players in the cabs aggregation segment, in the large cities. To hedge their risks, Singla added other services such as “Meal” (meal delivery) and “Fatafat” (goods delivery) – as B2C and B2B services. These services, however, had to be closed soon after because of stiff competition from the local players. Singla also adopted the inorganic growth path by acquiring “Sabkuch,” a grocery delivery logistics firm; “Yelo,” a platform that provided online access to businesses and “BookMyCab,” a taxi aggregation company. Faced with tapering growth after an initial steep rise, Singla had to confront a dilemma about the right method of ensuring growth in the face of competition. Complexity academic level Under graduate, masters in business administration and post graduation in the areas of entrepreneurship and strategy. Supplementary materials Teaching Notes are available for educators only. Subject code CSS 11: Strategy.
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Suntsova, Olesia. "DIGITALIZATION AND GLOBALIZATION IN TAXATION IN THE CONTEXT OF MODERN PRACTICE OF INTRODUCTION OF BLOCKCHAIN TECHNOLOGIES." 3, no. 3 (December 30, 2021): 27–35. http://dx.doi.org/10.26565/2786-4995-2021-3-03.
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One of the essential features of the new economy (neo-economy) is the increasing use of information and communication technologies, which led to the emergence and spread of the concept of "digitalization" as a process of digitalization, which is gradually formed within the post-industrial period of economic development. technical progress and innovative management methods, intellectualization of human capital, the use of advanced technologies, accelerated development of knowledge-intensive industries, giving priority to the production of knowledge and services, the mentality of creative, efficient, rational business. The vision of changes in taxation regarding the inclusion of blockchain technologies in the sphere of tax policy and introduction of taxation of tax differences of their exchange rate, as well as digitalization of cryptocurrency detection and taxation processes in Ukraine, which are currently outside the Tax Code of Ukraine. The world has changed significantly over the last decade. We live in an era of accelerating pace due to the rapid development of high technology. Traditional working tools used for years are losing relevance or disappearing altogether. Digital transformation, as a global trend, is steadily penetrating all industries. It affects both the most innovative and completely conservative areas. First of all, the client changes, both internal and external, his expectations, preferences and requirements. It forms a new demand, which must symmetrically correspond to supply. In the conditions of modification of the external environment there is an urgent need to reorient to modern methods of doing business. Only those companies that immediately translate their services into a more convenient and capacious mobile format of interaction with the client, will win the competition. Online retail and Internet banking, booking tickets and tours with aggregators or calling a taxi through mobile applications have become a reality of everyday life. According to Hampleton Partners, an international consulting firm specializing in technology mergers and acquisitions, the annual volume of transactions for the use of blockchain technology alone will be $6 billion. Many classic business models are giving way to technological innovation. The main message for businesses: "Upgrade or disappear", to which the modern tax system must also be adapted.
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Rammohan, Swaminathan, Rahul R. Marathe, and Nandan Sudarsanam. "Profitable market mechanism for platform-based aggregator taxi services." Transportation Research Interdisciplinary Perspectives 16 (December 2022): 100687. http://dx.doi.org/10.1016/j.trip.2022.100687.
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Markelova, A. A. "Civil liability of taxi-aggregation companies: Between contract and tort law." Digital Law Journal 2, no. 4 (December 30, 2021): 8–19. http://dx.doi.org/10.38044/2686-9136-2021-2-4-8-19.
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Technical and information progress undoubtably have an influence on the trade market and the consumer service sector of the modern economy. The sphere of taxi companies is no exception. When a user downloads a taxi-aggregation company’s application and orders a taxi, using its information about a carrier, this causes uncertainty in the qualifcation of the legal relationship between aggregator, carrier, and consumer. This ambiguity becomes critical if non-performance of the contract causes injury or non-pecuniary loss to a passenger. In this case, a concurrence arises between contact and tort qualifcation of the claim against the carrier and/or aggregator. The essay examines approaches to the distribution of liability between the aggregator, the carrier, and other persons who could contribute to causing harm, from the point of view of contract and tort law.
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Godwin, T. "Intra-City Call-Taxi Fleet Sizing using Petri Net Embedded Simulation Optimization." European Transport/Trasporti Europei, no. 89 (December 2022): 1–11. http://dx.doi.org/10.48295/et.2022.89.9.
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Call-taxi has seen tremendous growth during the past two decades and the smartphone app based call-taxi hiring for intra-city commuting has not only provided greater visibility to customers but also increased their expectations. Fleet sizing is an important decision to a call-taxi aggregator that strikes a balance between customer service in terms of call-taxi availability and the utilization of the fleet for a day’s forecasted demand. An optimization via simulation approach is developed for optimizing call-taxi fleet size. The simulation model embeds a Petri Net model of a call-taxi system where the customer requests and travel times are stochastic. Three optimization models are used to determine the fleet sizes, which are compared and inferences drawn. The developed approach can serve as a template for decision support tool for call-taxi service providers.
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Fryxell, Greta A. "NITZSCHIA BICAPITATA(BACILLARIOPHYCEAE) AND RELATED TAXA FROM OCEANIC AGGREGATIONS." Diatom Research 15, no. 1 (May 2000): 43–73. http://dx.doi.org/10.1080/0269249x.2000.9705486.
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Patwardhan, Avadhut Arun, and Neeraj Pandey. "Analyzing Role of E-SERVQUAL Constructs for Post-pandemic Recovery of Indian Taxi Aggregator Services." International Journal of Global Business and Competitiveness 16, S1 (November 2, 2021): 89–102. http://dx.doi.org/10.1007/s42943-021-00042-8.
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Kolosova, Yulia S., Grigory S. Potapov, Elizaveta A. Spitsyna, Vitaly M. Spitsyn, and Ivan N. Bolotov. "Are invasive hymenopteran species replacing native mud dauber wasp-associated taxa on the Seychelles Archipelago?" Ecologica Montenegrina 50 (January 11, 2022): 1–16. http://dx.doi.org/10.37828/em.2022.50.1.
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Nest aggregations of mud dauber wasps increase substrate heterogeneity and provide suitable sites for colonization by other invertebrate species. The mud dauber wasp Sceliphron fuscum Klug, 1801 (Hymenoptera: Sphecidae) abundantly occurs throughout the Seychelles Archipelago, Republic of Seychelles. Here, we estimated the taxonomic richness of the hymenopteran assemblage associated with S. fuscum’s nest aggregations, using material collected from the Inner Seychelles in 2016. Furthermore, we examine available historical survey data in order to assess possible changes in this association over decades. We discovered that from 1936 to 1938, seven hymenopteran species were associated with the nest aggregations of S. fuscum on Mahé and Praslin islands, representing six native taxa and one invasive species. From the material collected in 2016, we found one native and three invasive hymenopteran species associated to S. fuscum nests. Our findings could indicate a replacement of native species associated with the mud dauber wasps’ nest aggregations by recently introduced alien taxa on the Seychelles Archipelago.
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Zhang, Wenbo, and Chang Xu. "Exploring App-Based Taxi Movement Patterns from Large-Scale Geolocation Data." ISPRS International Journal of Geo-Information 10, no. 11 (November 8, 2021): 751. http://dx.doi.org/10.3390/ijgi10110751.
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This study is designed to leverage ubiquitous mobile computing techniques on exploring app-based taxi movement patterns in large cities. To study patterns at different scales, we comprehensively explore both occupied and unoccupied vehicle movement characteristics through not only individual trips but also their aggregations. Moran’s I and its variations are applied to explore spatial autocorrelations among different rides. PageRank centrality is applied for a functional network representing traffic flows to discover places of interest. Gyration radius measures the scope of passenger mobility and driver passenger searching. Moreover, cumulative distribution and data visualization techniques are adopted for trip level characteristics and features analysis. The results indicate that the app-based taxi services are serving more neighborhoods other than downtown areas by taking large proportion of relatively shorter trips and contributing to net increase in total taxi ridership although net decrease in downtown areas. The spatial autocorrelations are significant not only within each service but also among services. With the smartphone-based applications, app-based taxi services are able to search passengers in a larger area and move more efficiently during both occupied and unoccupied periods. Mining from huge empty trip trajectory by app-based taxis, we also identify the existence of stationary/stops state and circulations.
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Yan, J., L. Xiang, C. Wu, and H. Wu. "CITY-SCALE TAXI DEMAND PREDICTION USING MULTISOURCE URBAN GEOSPATIAL DATA." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLIII-B4-2020 (August 24, 2020): 213–20. http://dx.doi.org/10.5194/isprs-archives-xliii-b4-2020-213-2020.
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Abstract. Real-time, accurate taxi demand prediction plays an important role in intelligent traffic system. It can help manage taxi patching and minimize the time and energy waste caused by waiting. In the era of big data, a diversity of urban data and increasingly complex traffic data have been collected and published. Traditional forecasting methods have been unable to cope with the heterogeneous massive traffic data, whereas deep learning, as a new data-oriented technique, has been widely used in the field of traffic prediction. This paper aims to utilize multisource data and deep learning techniques to improve the accuracy of taxi demand prediction. In this paper, a joint guidance residual network JG-Net is proposed for city-scale taxi demand prediction. Taxi order data and multiple urban geospatial data POI, road network and population distribution data) are integrated into the JG-Net. Regional features are considered in the prediction process by three guidance branches composed of pixel-adaptive convolutional networks, each of which applies one type of urban data. JG-Net assigns learnable weights to different branches and regions to combine the output of the branches, then further aggregates weather and time information to forecast the taxi demand. Extensive experiments and analyses are conducted, which show our method outperforms traditional methods. The mean square error of the prediction result on the testing set is 1.868, which is 12.3% lower than related models. The positive influence of combining multiple geospatial data is also validated by ablation experiments.
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Shevgunov, Timofey, Zhanna Vavilova, Tatiana Kravchenko, and Liubov Levchenko. "Development of a rating system assessing the quality of the service provided by drivers in a taxi aggregator company." Business Informatics 16, no. 4 (December 30, 2022): 68–81. http://dx.doi.org/10.17323/2587-814x.2022.4.68.81.
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Zhang, Xianjie, Pradeep Varakantham, and Hao Jiang. "Future Aware Pricing and Matching for Sustainable On-Demand Ride Pooling." Proceedings of the AAAI Conference on Artificial Intelligence 37, no. 12 (June 26, 2023): 14628–36. http://dx.doi.org/10.1609/aaai.v37i12.26710.
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The popularity of on-demand ride pooling is owing to the benefits offered to customers (lower prices), taxi drivers (higher revenue), environment (lower carbon footprint due to fewer vehicles) and aggregation companies like Uber (higher revenue). To achieve these benefits, two key interlinked challenges have to be solved effectively: (a) pricing -- setting prices to customer requests for taxis; and (b) matching -- assignment of customers (that accepted the prices) to taxis/cars. Traditionally, both these challenges have been studied individually and using myopic approaches (considering only current requests), without considering the impact of current matching on addressing future requests. In this paper, we develop a novel framework that handles the pricing and matching problems together, while also considering the future impact of the pricing and matching decisions. In our experimental results on a real-world taxi dataset, we demonstrate that our framework can significantly improve revenue (up to 17% and on average 6.4%) in a sustainable manner by reducing the number of vehicles (up to 14% and on average 10.6%) required to obtain a given fixed revenue and the overall distance travelled by vehicles (up to 11.1% and on average 3.7%). That is to say, we are able to provide an ideal win-win scenario for all stakeholders (customers, drivers, aggregator, environment) involved by obtaining higher revenue for customers, drivers, aggregator (ride pooling company) while being good for the environment (due to fewer number of vehicles on the road and lesser fuel consumed).
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Koltchin, Sergey P., and Georgy A. Suzdalsky. "PECULIARITIES OF TAX ACCOUNTING AND CALCULATION OF PERSONAL INCOME TAX OF YANDEX.TAXI DRIVERS." EKONOMIKA I UPRAVLENIE: PROBLEMY, RESHENIYA 3, no. 11 (2021): 191–94. http://dx.doi.org/10.36871/ek.up.p.r.2021.11.03.030.
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The article examines the features of tax accounting and the calculation of personal income tax associated with the problem of taxation of the income of drivers of the Yandex.Taxi aggregator service, a step-by-step algorithm for the operation of the online taxi ordering system, identifies problems associated with the responsibility of the participants in the process, as well as with the occurrence of situations when the income of drivers is not taxed. As a result, it is concluded that it is necessary to oblige Yandex.Taxi LLC at the legislative level to conclude an employment contract with drivers and act as a tax agent in respect of the income they receive in order to increase tax control over the completeness of the calculation and payment of personal income tax, as well as to clearly define the boundaries of liability of the participants in the process online taxi ordering.
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Johnston, M. Andrew, Rolf Aalbu, and Nico Franz. "An updated checklist of the Tenebrionidae sec. Bousquet et al. 2018 of the Algodones Dunes of California, with comments on checklist data practices." Biodiversity Data Journal 6 (June 14, 2018): e24927. http://dx.doi.org/10.3897/bdj.6.e24927.
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Generating regional checklists for insects is frequently based on combining data sources ranging from literature and expert assertions that merely imply the existence of an occurrence to aggregated, standard-compliant data of uniquely identified specimens. The increasing diversity of data sources also means that checklist authors are faced with new responsibilities, effectively acting as filterers to select and utilize an expert-validated subset of all available data. Authors are also faced with the technical obstacle to bring more occurrences into Darwin Core-based data aggregation, even if the corresponding specimens belong to external institutions. We illustrate these issues based on a partial update of the Kimsey et al. 2017 checklist of darkling beetles - Tenebrionidae sec. Bousquet et al. 2018 - inhabiting the Algodones Dunes of California. Our update entails 54 species-level concepts for this group and region, of which 31 concepts were found to be represented in three specimen-data aggregator portals, based on our interpretations of the aggregators' data. We reassess the distributions and biogeographic affinities of these species, focusing on taxa that are precinctive (highly geographically restricted) to the Lower Colorado River Valley in the context of recent dune formation from the Colorado River. Throughout, we apply taxonomic concept labels (taxonomic name according to source) to contextualize preferred name usages, but also show that the identification data of aggregated occurrences are very rarely well-contextualized or annotated. Doing so is a pre-requisite for publishing open, dynamic checklist versions that finely accredit incremental expert efforts spent to improve the quality of checklists and aggregated occurrence data.
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Jessen, Stefan, Walter Bujnoch, Günther Zenner, and Christoph Stark. "Dryopteris lacunosa – eine neue Art des Dryopteris-affinis-Aggregats (Dryopteridaceae, Pteridophyta)." Kochia 5 (February 28, 2011): 9–31. http://dx.doi.org/10.21248/kochia.v5.101.
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Eine weitere Sippe des Dryopteris-affinis-Aggregats wird als Art, D. lacunosa S. Jess., Zenner, Ch. Stark & Bujnoch beschrieben. Sie lässt sich morphologisch von den anderen bisher beschriebenen Taxa des Aggregats unterscheiden, ist triploid und zeigt spezifische Phloroglucid- und RAPD-Bandenmuster. Bisher sind Funde aus Norditalien, Österreich, der Schweiz, Frankreich, Deutschland, Großbritannien und Irland belegt.
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Chapman, Nicola D., Colin G. Moore, Dan B. Harries, and Alastair R. Lyndon. "The community associated with biogenic reefs formed by the polychaete, Serpula vermicularis." Journal of the Marine Biological Association of the United Kingdom 92, no. 4 (July 22, 2011): 679–85. http://dx.doi.org/10.1017/s0025315411000701.
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The study aims to provide the first detailed account of the diversity and composition of the community associated with biogenic reefs formed by serpulid worms. Ten reefs (aggregations of calcareous Serpula vermicularis tubes), spanning a broad size-range, were collected from Loch Creran, Scotland, a Special Area of Conservation designated principally for the protection of its biogenic reefs. Total faunal abundance was strongly linearly related to reef weight, whilst taxon richness exhibited a hyperbolic relationship with reef size. 278 taxa were recorded from the ten reefs, with a reef of 0.1 m2 area supporting 163 taxa and 12756 individuals, which appears to represent considerable augmentation of diversity and abundance for sedimentary areas of the loch where the reefs occur. The reef assemblage was dominated by polychaetes (94 taxa), molluscs (70 taxa) and crustaceans (45 taxa). Species composition varied with reef size, although reefs greater than 25 cm width exhibited relatively little variation. In comparison with other biogenic polychaete habitats, S. vermicularis reefs appear to support a highly diverse community, which exhibits a high degree of similarity with that found in association with aggregations of the horse mussel, Modiolus modiolus. The presence of the Connemara clingfish, Lepadogaster candollei, rarely recorded at such a northerly latitude, on several reefs, indicates that the reef habitat may provide a stronghold for this species at the edge of its biogeographical range.
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Coyle, Kenneth O. "Acoustic estimates of zooplankton biomass and distribution: application of canonical correlation to scaling of multifrequency acoustic data." Canadian Journal of Fisheries and Aquatic Sciences 57, no. 11 (November 1, 2000): 2306–18. http://dx.doi.org/10.1139/f00-155.
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A technique is presented that can be used to scale multifrequency acoustic data to estimates of wet weight biomass from concurrently collected zooplankton samples. The technique uses canonical correlation to identify those taxa that correlate with the acoustic data. Canoncial correlation is then used to compute scaling coefficients that can be used to convert transect data to biomass equivalents for the correlating taxa. Examples are offered to illustrate how the technique can identify euphausiid aggregates, pteropods, and larval fish. The technique can discriminate between taxa with gas bladders, taxa with shells, and fluid-filled taxa. It also has the advantage of quantifying the correlation between the target taxa and acoustic data, thus allowing the researcher to judge the usefulness of the acoustic data in characterizing the distribution and density of the zooplankton taxa.
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Chen, Wenjun, Tianyun Shen, Lijun Wang, and Kefeng Lu. "Oligomerization of Selective Autophagy Receptors for the Targeting and Degradation of Protein Aggregates." Cells 10, no. 8 (August 5, 2021): 1989. http://dx.doi.org/10.3390/cells10081989.
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The selective targeting and disposal of solid protein aggregates are essential for cells to maintain protein homoeostasis. Autophagy receptors including p62, NBR1, Cue5/TOLLIP (CUET), and Tax1-binding protein 1 (TAX1BP1) proteins function in selective autophagy by targeting ubiquitinated aggregates through ubiquitin-binding domains. Here, we summarize previous beliefs and recent findings on selective receptors in aggregate autophagy. Since there are many reviews on selective autophagy receptors, we focus on their oligomerization, which enables receptors to function as pathway determinants and promotes phase separation.
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Surmik, Dawid, Mariusz A. Salamon, Agnieszka Chećko, and Karolina Kędroń. "Ophiuroids from the Middle Triassic (Muschelkalk) of Sadowa Góra, Jaworzno (southern Poland)." Geology, Geophysics and Environment 46, no. 2 (October 16, 2020): 175. http://dx.doi.org/10.7494/geol.2020.46.2.175.
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Ophiuroids belonging to Aspiduriella sp., Aspiduriella similis (Eck), and Arenorbis sp. are described from the Middle Triassic (Muschelkalk) strata of the Sadowa Góra Quarry (Jaworzno) in southern Poland. This is the only Polish location where three taxa of these ophiuroids have been found in one stratigraphic horizon (1st Wellenkalk). To date, only single taxa have been found in the Triassic sections of the eastern part of the Germanic Basin. Finally, other ophiuroid mass aggregations also known from Poland are presented.
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Jasinoski, Sandra C., and Fernando Abdala. "Aggregations and parental care in the Early Triassic basal cynodontsGalesaurus planicepsandThrinaxodon liorhinus." PeerJ 5 (January 10, 2017): e2875. http://dx.doi.org/10.7717/peerj.2875.
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Non-mammaliaform cynodonts gave rise to mammals but the reproductive biology of this extinct group is still poorly known. Two exceptional fossils ofGalesaurus planicepsandThrinaxodon liorhinus, consisting of juveniles closely associated with an adult, were briefly described more than 50 years ago as examples of parental care in non-mammaliaform cynodonts. However, these two Early Triassic fossils have largely been excluded from recent discussions of parental care in the fossil record. Here we re-analyse these fossils in the context of an extensive survey of other aggregations found in these two basal cynodont taxa. Our analysis revealed six other unequivocal cases of aggregations inThrinaxodon, with examples of same-age aggregations among immature or adult individuals as well as mixed-age aggregations between subadult and adult individuals. In contrast, only one additional aggregation ofGalesauruswas identified. Taking this comprehensive survey into account, the two previously described cases of parental care inGalesaurusandThrinaxodonare substantiated. The juveniles are the smallest specimens known for each taxon, and the size difference between the adult and the two associated juveniles is the largest found for any of the aggregations. The juveniles ofThrinaxodonare approximately only 37% of the associated adult size; whereas inGalesaurus, the young are at least 60% of the associated adult size. In each case, the two juvenile individuals are similar in size, suggesting they were from the same clutch. Even though parental care was present in bothGalesaurusandThrinaxodon, intraspecific aggregations were much more common inThrinaxodon, suggesting it regularly lived in aggregations consisting of both similar and different aged individuals.
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Shantsila, Eduard, Silvia Montoro-Garcia, Luke Tapp, Stavros Apostolakis, Benjamin Wrigley, and Gregory Lip. "Fibrinolytic status in acute coronary syndromes: Evidence of differences in relation to clinical features and pathophysiological pathways." Thrombosis and Haemostasis 108, no. 07 (2012): 32–40. http://dx.doi.org/10.1160/th12-01-0011.
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SummaryLimited data are available on the role of innate fibrinolysis in acute coronary syndromes (ACS). In the present study we evaluated the dynamic alterations of fibrinolytic markers in patients presenting with ACS. Tissue-type-(tPA) and urokinase type-(uPA) plasminogen activators, plasminogen activator inhibitor (PAI-1) antigen and activity and thrombin activatable fibrinolysis inhibitor (TAFI) were analysed in 50 patients with ST elevation myocardial infarction (STEMI), 47 non-STEMI patients (NSTEMI), 40 patients with stable coronary artery disease (CAD) and 39 controls. The parameters were measured on day 1 and days 3, 7 and 30. Counts of monocyte subsets, monocyte-platelet aggregates and plasma inflammatory cytokines were assessed on admission. On day 1, TAFI was higher in NSTEMI vs. STEMI (p<0.001) while PAI-1 activity was higher in STEMI (p<0.001). In STEMI, uPA activity levels was low on day 1 but significantly increased on day 30 (p<0.001). TAFI levels were increased in NSTEMI on day 1 and gradually reduced by day 30 (p<0.05). In STEMI, TAFI levels peaked at day 7 (p<0.05) and dropped significantly by day 30 (p<0.05). CD14++CD16+ monocytes were independently associated with PAI-1 activity in ACS (p=0.03). Monocyte-platelet aggregates rather than platelet-free monocytes were an independent determinant of tPA, PAI-1 antigen and TAFI on a multivariate analysis (p<0.05). There are significant differences in fibrinolytic activity between patients with STEMI and NSTEMI. These changes could reflect the role of these factors in post-MI myocardial healing. Monocyteplatelet interactions are independently associated with the regulation of the fibrinolytic status in ACS.Note: The editorial process for this article was fully handled by Prof. Christian Weber, Editor-in-Chief.
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Wu, Tianhao, Mingzhi Jiang, Yinhui Han, Zheng Yuan, Xinhang Li, and Lin Zhang. "A Traffic-Aware Federated Imitation Learning Framework for Motion Control at Unsignalized Intersections with Internet of Vehicles." Electronics 10, no. 24 (December 7, 2021): 3050. http://dx.doi.org/10.3390/electronics10243050.
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The wealth of data and the enhanced computation capabilities of Internet of Vehicles (IoV) enable the optimized motion control of vehicles passing through an intersection without traffic lights. However, more intersections and demands for privacy protection pose new challenges to motion control optimization. Federated Learning (FL) can protect privacy via model interaction in IoV, but traditional FL methods hardly deal with the transportation issue. To address the aforementioned issue, this study proposes a Traffic-Aware Federated Imitation learning framework for Motion Control (TAFI-MC), consisting of Vehicle Interactors (VIs), Edge Trainers (ETs), and a Cloud Aggregator (CA). An Imitation Learning (IL) algorithm is integrated into TAFI-MC to improve motion control. Furthermore, a loss-aware experience selection strategy is explored to reduce communication overhead between ETs and VIs. The experimental results show that the proposed TAFI-MC outperforms imitated rules in the respect of collision avoidance and driving comfort, and the experience selection strategy can reduce communication overheads while ensuring convergence.
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Volkova, E. A. "The first finding of aegagropilious, or algal balls, in the oldest freshwater Lake Baikal." Limnology and Freshwater Biology, no. 1 (2022): 1205–8. http://dx.doi.org/10.31951/2658-3518-2022-a-1-1205.
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Abstract. Free-floating algal aggregations, or aegagropilious, are a rare phenomenon known from some freshwater or marine environments worldwide. In September 2014, unusual green algal balls were washed ashore in Ludar Bay on the west coast of the northern basin of Lake Baikal. The paper describes these algal aggregations and characterizes their composition. The Baikal algal balls mainly consisted of green filamentous algae of the family Cladophoraceae, such as Cladophora glomerata, Rhizoclonium sp., and Chaetomorpha sp. Other prominent components of the balls were numerous filaments of Spirogyra and Oedogonium. These taxa are known for their rapid growth in response to nutrients increase. As the result of the hyperproduction of filamentous benthic algae in the coastal zone of Lake Baikal, new living forms such as aegagropilious-like aggregations have been occurring. The algal balls signify the adaptive capacities of the Lake Baikal algal communities and might retain their functioning in the natural ecosystem s self-purification processes.
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SHIVAROV, Veselin V., Cvetomir M. DENCHEV, and Holger THÜS. "Ecology and distribution of Dermatocarpon (Verrucariaceae, Ascomycota) in the catchment areas of two Bulgarian rivers." Lichenologist 50, no. 6 (November 2018): 679–90. http://dx.doi.org/10.1017/s0024282918000452.
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AbstractTemperature preferences and small-scale distribution patterns of four Dermatocarpon taxa in the catchment areas of two Bulgarian rivers were analyzed. Taxa with an overall alpine or arctic-alpine distribution were restricted to microhabitats with the lowest water and rock surface temperatures. A trend for increasing Dermatocarpon rivulorum thallus diameter and colony size (aggregates of thalli) with decreasing temperature was identified. Data on pH and conductivity of the water for the study sites are provided for all taxa. Dermatocarpon arnoldianum is reported for the first time from Bulgaria, confirmed by ITS sequence data, and its known range extends to South-East Europe. All previous records of D. rivulorum from Bulgaria were based on misidentified specimens of D. arnoldianum. Freshwater taxa of Dermatocarpon are proposed as a tool for monitoring the biological effects of temperature changes due to global climate change. Thallus and colony size are recommended as additional features for monitoring populations of threatened Dermatocarpon species.
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Nelson, Cara R., and Charles B. Halpern. "Short-term effects of timber harvest and forest edges on ground-layer mosses and liverworts." Canadian Journal of Botany 83, no. 6 (June 1, 2005): 610–20. http://dx.doi.org/10.1139/b05-036.
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Limited information exists on the effects of forest management practices on bryophytes, despite their importance to forest ecosystems. We examined short-term responses of ground-layer bryophytes to logging disturbance and creation of edges in mature Pseudotsuga forests of western Washington (USA). The abundance and richness of species were measured in four 1-ha forest aggregates (patches of intact forest) and in surrounding logged areas before and after structural retention harvests. One year after treatment, species richness, total cover, and frequency of most moss and liverwort taxa declined within harvest areas. Within forest aggregates, mosses did not show significant edge effects; however, richness and abundance of liverworts declined with proximity to the aggregate edge. Our results suggest that, over short time frames, 1-ha-sized aggregates are sufficient to maintain most common mosses through structural retention harvests but are not large enough to prevent declines or losses of liverworts. Thus, current standards for structural retention, which allow for aggregates as small as 0.2 ha, may be inadequate to retain the diversity and abundance of species found in mature, undisturbed forests.Key words: bryophyte, edge effects, forest borders, forest management, logging effects, structural retention harvest.
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CAVANAUGH, DAVID P., and RICHARD V. STERNBERG. "ANALYSIS OF MORPHOLOGICAL GROUPINGS USING ANOPA, A PATTERN RECOGNITION AND MULTIVARIATE STATISTICAL METHOD: A CASE STUDY INVOLVING CENTRARCHID FISHES." Journal of Biological Systems 12, no. 02 (June 2004): 137–67. http://dx.doi.org/10.1142/s0218339004001117.
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Morphological relationships within and among taxonomic groups can be very complicated, with anatomical data often supporting two or more incongruent groupings. One possibility is that incongruent character states are taxonomically informative, although in an N-dimensional taxic space. To test the above, morphological relationships of centrarchid fish species were examined using a new pattern recognition, multivariate correlation, and multivariate statistical analysis method (ANOPA). The objective of ANOPA is to identify N-dimensional pattern space correlations among character states, relations that cannot be detected with standard phenetic or phylogenetic approaches. ANOPA provides a solution to an inherent weakness in statistical analysis which occurs in the face of set classification ambiguity, where there is no a priori reason to assign a membership or class identification within multivariate statistical groups. This approach revealed the percoid fish family Centrarchidae to be a statistically significant, cohesive group with complicated internal relationships. Centrarchid taxa are resolved into three major generic aggregates by two and three-dimensional ANOPA, and discrete subgroups were also detected. The complex interrelationships within the Centrarchidae cannot be readily collapsed to a bifurcating tree-structure, explaining the multitude of conflicting phylogenetic hypotheses that have been presented. This is the first robust study of anatomical disparity in teleostean fishes. Applications of ANOPA to the study of morphological gaps, complex taxonomic patterns, and anatomical disparity are discussed.
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Lewis, Sara M., Lynn Faust, and Raphaël De Cock. "The Dark Side of the Light Show: Predators of Fireflies in the Great Smoky Mountains." Psyche: A Journal of Entomology 2012 (2012): 1–7. http://dx.doi.org/10.1155/2012/634027.
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In the Great Smoky Mountains of East Tennessee, the Light Show is a popular seasonal attraction created by thousands of courting malePhotinus carolinusfireflies (Coleoptera: Lampyridae) that flash in synchrony to locate females. This study was undertaken to provide a temporal snapshot of whether invertebrate predators are active within these dense and conspicuous firefly breeding aggregations. In addition, we examined whether femalePhoturisfireflies, which are specialist predators on other fireflies, show any feeding preferences within the diverse local firefly fauna. A field survey revealed a surprisingly diverse suite of generalist insectivores feeding on fireflies withinP. carolinusbreeding aggregations. In addition, laboratory studies revealed major differences in prey consumption rates whenPhoturispredators were given access to several lampyrid taxa. This suite of generalist and specialist predators appears to create a complex selective landscape that is predicted to be a powerful force shaping the evolution of firefly defenses.
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Chesnokov, Aleksey A. "Threats to the Digital Markets Development Basing on Analysis of the «Yandex.Taxi» Aggregator." Journal of Modern Competition 15, no. 3 (August 13, 2021): 106–18. http://dx.doi.org/10.37791/2687-0657-2021-15-3-106-118.
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The article is devoted to identifying and in-depth analysis of those threats, that arise when implementing aggregating digital platforms. The objectives of the research are to consistently consider the following problems of modern digital platforms: price discrimination, dissatisfaction on the part of performers, violation of the spirit of labor legislation, unfair competition, violation of the principle of distribution of risks and profits, the danger of competition of digital platforms. Research methods: analysis and synthesis of information from domestic and foreign sources, statistical analysis, historical analysis. The study identified and analyzed six types of threats that come from digital platforms. On the example of “Yandex. Taxi” aggregator and examples from international practice it is shown that all these threats take place all over the world, including Russia. It is also shown that these threats and their growing influence are directly related to the growing influence of digital platforms, which are strengthening their positions in relation to citizens, organizations and government. The following generalizing conclusions were made: digital platforms have ample opportunities to conduct unfair competition, violation of labor, antimonopoly and other legislation; individual cases of local violations or unfair actions add up to a single model of the development of threats around the world; in the global digital wars of corporations, the losers are citizens and states. To reduce risks and reach a long-term stabilization of digitalization threats, it is necessary to develop and implement significant methods of public and state control in the field of high technologies; first of all - to reform the labor and related legislation so that it takes into account the realities of the modern development of information technologies. It is shown that domestic legislation is still seriously lagging behind modern trends in the socio-economic structure. The research results are applicable to modern Russian jurisprudence, economics and sociology, where they relate to the issues of the digital economy and the activities of digital platform.
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White, A. P., D. L. Gibson, S. K. Collinson, P. A. Banser, and W. W. Kay. "Extracellular Polysaccharides Associated with Thin Aggregative Fimbriae of Salmonella enterica Serovar Enteritidis." Journal of Bacteriology 185, no. 18 (September 15, 2003): 5398–407. http://dx.doi.org/10.1128/jb.185.18.5398-5407.2003.
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ABSTRACT Lipopolysaccharide (LPS) O polysaccharide was identified as the principle factor impeding intercellular formation of intact thin aggregative fimbriae (Tafi) in Salmonella enterica serovar Enteritidis. The extracellular nucleation-precipitation assembly pathway for these organelles was investigated by quantifying fimbrial formation between ΔagfA (AgfA recipient) and ΔagfB (AgfA donor) cells harboring mutations in LPS (galE::Tn10) and/or cellulose (ΔbcsA) synthesis. Intercellular complementation could be detected between ΔagfA and ΔagfB strains only when both possessed the galE mutation. LPS O polysaccharide appears to be an impenetrable barrier to AgfA assembly between cells but not within individual cells. The presence of cellulose did not restrict Tafi formation between cells. Transmission electron microscopy of w + S. enterica serovar Enteritidis 3b cells revealed diffuse Tafi networks without discernible fine structure. In the absence of cellulose, however, individual Tafi fibers were clearly visible, appeared to be occasionally branched, and showed the generally distinctive appearance described for Escherichia coli K-12 curli. A third extracellular matrix component closely associated with cellulose and Tafi was detected on Western blots by using immune serum raised to whole, purified Tafi aggregates. Cellulose was required to tightly link this material to cells. Antigenically similar material was also detected in S. enterica serovar Typhimurium and one diarrheagenic E. coli isolate. Preliminary analysis indicated that this material represented an anionic, extracellular polysaccharide that was distinct from colanic acid. Therefore, Tafi in their native state appear to exist as a complex with cellulose and at least one other component.
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Hennessy, Georgia, Dave Goulson, and Francis L. W. Ratnieks. "Population assessment and foraging ecology of nest aggregations of the rare solitary bee, Eucera longicornis at Gatwick Airport, and implications for their management." Journal of Insect Conservation 24, no. 6 (August 27, 2020): 947–60. http://dx.doi.org/10.1007/s10841-020-00266-8.
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Abstract Eucera longicornis is a rare solitary bee that is in decline throughout its range in Britain and other European countries. Two nest aggregations that had been previously discovered in 2014 on land owned and managed by Gatwick Airport, Southern England, were studied in 2017, 2018 and 2019 to obtain information relevant to their conservation. Population estimates using mark recapture showed that the larger aggregation had a maximum population estimate of 659 individuals in 2018, with the smaller aggregation reaching a maximum population estimate of 221 in 2019. In terms of foraging requirements, microscopic analysis of pollen samples from females returning from their nests identified a total of 12 plant taxa across all years and both aggregations. Fabaceae pollen was present in 100% of samples and on average comprised 90% of each sample, indicating that the species is oligolectic. Both nest aggregations were on sloping banks of exposed soil arising from land management by the airport in 1999. Floral surveys of the landscape indicate that within 100 m of both aggregations Fabaceae species are the most abundant due to the presence of a legume rich wildflower meadow alongside the adjacent river Mole, which was sown by Gatwick Airport. Eucera longicornis at Gatwick Airport are an example of how if managed appropriately, industrial areas can provide valuable refuges for rare wildlife. Although there is no imminent risk of the populations going extinct, management and monitoring suggestions are provided to ensure these populations persist.
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Amarante, Cristina Fernandes do, Wagner de Souza Tassinari, José Luis Luque, and Maria Julia Salim Pereira. "Factors associated with parasite aggregation levels in fishes from Brazil." Revista Brasileira de Parasitologia Veterinária 24, no. 2 (June 12, 2015): 174–82. http://dx.doi.org/10.1590/s1984-29612015031.
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The degree of parasite aggregation is determined by a number of factors that are not well understood. In total, 3,746 fish from 73 species and their parasites were analyzed to determine associations between the degree of aggregation by taxon and specific characteristics of the fish. A multiple linear regression (95% confidence interval - CI) was used to show that in most taxa, the degree of parasite aggregation was significantly higher in freshwater fish and schooling fish but varied according to taxon in relation to gender, habitat and feeding habits. Parasite aggregations were also significantly increased in fish with a large number of parasitic larvae and greater body length in all evaluated taxa. Because the coefficients of determination of the models were lower than 60% for all taxa, other factors may be involved in parasite aggregation. Conversely, marked significance was observed for the tested variables in relation to taxon dependence, which indicates that additional studies should be performed for these factors using comprehensive databases with larger samples per parasite species.
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Genitsaris, Savvas, Natassa Stefanidou, Maria Moustaka-Gouni, Ulrich Sommer, and George Tsipas. "Variability and Community Composition of Marine Unicellular Eukaryote Assemblages in a Eutrophic Mediterranean Urban Coastal Area with Marked Plankton Blooms and Red Tides." Diversity 12, no. 3 (March 21, 2020): 114. http://dx.doi.org/10.3390/d12030114.
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The Thessaloniki Bay is a eutrophic coastal area which has been characterized in recent years by frequent and intense phytoplankton blooms and red tides. The aim of the study was to investigate the underexplored diversity of marine unicellular eukaryotes in four different sampling sites in Thessaloniki Bay during a year of plankton blooms, red tides, and mucilage aggregates. High-Throughput Sequencing (HTS) was applied in extracted DNA from weekly water samples targeting the 18S rRNA gene. In almost all samples, phytoplankton blooms and/or red tides and mucilage aggregates were observed. The metabarcoding analysis has detected the known unicellular eukaryotic groups frequently observed in the Bay, dominated by Bacillariophyta and Dinoflagellata, and revealed taxonomic groups previously undetected in the study area (MALVs, MAST, and Cercozoa). The dominant OTUs were closely related to species known to participate in red tides, harmful blooms, and mucilage aggregates. Other OTUs, present also during the blooms in low abundance (number of reads), were closely related to known harmful species, suggesting the occurrence of rare taxa with potential negative impacts on human health not detectable with classical microscopy. Overall, the unicellular eukaryote assemblages showed temporal patterns rather than small-scale spatial separation responding to the variability of physical and chemical factors.
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Sapozhnikov, Ph V., O. Yu Kalinina, L. E. Reichard, B. A. Solovjov, A. Kowan, and L. Farmer. "MASS MACROCOLONIES MELOSIRA ARCTICA FORMING ON THE SURFACE OF ICE IN THE NORTH POLE AREA." Journal of Oceanological Research 47, no. 4 (December 2, 2019): 53–61. http://dx.doi.org/10.29006/1564-2291.jor-2019.47(4).3.
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In early August 2019, in the area of the North Pole, a massive development of ice flora communities on the surface of perennial ice was observed. Macroaggregates of fibers with a thickness of 0.5–0.8 cm, compactly intertwined and forming “brain-like” structures up to 10-15 cm in size, had a pale pink color and covered the bottom of freshwater puddles with extensive fields. The aggregates were formed by diatom taxocenes based on the colonies of Melosira arctica, their polymer matrix, as well as another 35 taxa of marine and brackishmarine diatoms, some of which also performed structure-forming functions. With high probability, the development of aggregates occurred at the thawing points of the tops of the pore channels in the ice, through which the spongy plexuses of the algocenoses were fed with salt water. The phenomenon of formation and mass development of such macrostructures is described for the first time.
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Neis, Christian, Bernd Morgenstern, and Kaspar Hegetschweiler. "Hydrogen-bonding patterns in bis[2,4,6-triazaniumylcyclohexane-1,3,5-tris(olate)-κ3O,O′,O′′]germanium(IV) tetrachloride hexahydrate." Acta Crystallographica Section C Structural Chemistry 72, no. 1 (January 1, 2016): 28–34. http://dx.doi.org/10.1107/s2053229615023165.
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A first preliminary report on the crystal structure of a hydrated salt formulated as [Ge(taci)2]Cl4·13H2O (taci is 1,3,5-triamino-1,3,5-trideoxy-cis-inositol) appeared more than 20 years ago [Ghisletta (1994). PhD thesis, ETH Zürich. Switzerland]. At that time it was not possible to discriminate unambiguously between the positions of some of the chloride ions and water O atoms, and disorder was thus postulated. In a new determination, a conclusive scheme of hydrogen bonding proves to be a particularly appealing aspect of the structure. Single crystals of the title compound, C12H30GeN6O64+·4Cl−·6H2O or [Ge(taci)2]2Cl8·12H2O, were grown from an aqueous solution by slow evaporation of the solvent. The two [Ge(taci)2]4+cations exhibit a double-adamantane-type structure with exclusive O-atom coordination and approximateD3dsymmetry. The taci ligands adopt a zwitterionic form with deprotonated hydroxy groups and protonated amino groups. Both cations are hydrogen bonded to six water molecules. The structure of the hydration shell of the two cations is, however, slightly different. The {[Ge(taci)2]·6H2O}4+aggregates are interlinked in all three dimensions by further hydrogen bonds of the types N—H...Cl...H—N, N—H...O(H)2...H—N, (Ge)O...H—O(H)...H—N, N—H...O(H)—H...Cl...H—N, (Ge)O...H—O—H...Cl...H—N, N—H...O(H)—H...Cl...H—(H)O...H—N, (Ge)O...H—O—H...Cl...H—(H)O...H—N and Ge(O)...H—O—H...Cl...H—O—H...O(Ge).
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Santiago-Blay, Jorge A., Pierre Jolivet, and Krishna K. Verma. "A natural history of conspecific aggregations in terrestrial arthropods, with emphasis on cycloalexy in leaf beetles (Coleoptera: Chrysomelidae)." Terrestrial Arthropod Reviews 5, no. 3-4 (2012): 289–355. http://dx.doi.org/10.1163/18749836-05031054.
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Aggregations of conspecifics are ubiquitous in the biological world. In arthropods, such aggregations are generated and regulated through complex interactions of chemical and mechanical as well as abiotic and biotic factors. Aggregations are often functionally associated with facilitation of defense, thermomodulation, feeding, and reproduction, amongst others. Although the iconic aggregations of locusts, fireflies, and monarch butterflies come to mind, many other groups of arthropods also aggregate. Cycloalexy is a form of circular or quasicircular aggregation found in many animals. In terrestrial arthropods, cycloalexy appears to be a form of defensive aggregation although we cannot rule out other functions, particularly thermomodulation. In insects, cycloalexic-associated behaviors may include coordinated movements, such as the adoption of seemingly threatening postures, regurgitation of presumably toxic compounds, as well as biting movements. These behaviors appear to be associated with attempts to repel objects perceived to be threatening, such as potential predators or parasitoids. Cycloalexy has been reported in some adult Hymenoptera as well as immature insects. Nymphs of the orders Hemiptera (including Homoptera) as well as larvae of the orders Neuroptera, Coleoptera, Diptera, Hymenoptera, and, in a less circular fashion, the Lepidoptera, cycloalex. There are remarkable convergences in body form, life habit, and tendencies to defend themselves in the social larval Coleoptera, particularly chrysomelids, social larval Lepidoptera, and social larval Hymenoptera. In immature insects, the cycloalexing organisms can be arranged with either heads or abdominal apices juxtaposed peripherally and other conspecifics may fill in the center of the array. In the Chrysomelidae, the systematic focus of this review, species in the generaLema,Lilioceris(Criocerinae),Agrosteomela,Chrysophtharta,Eugonycha,Gonioctena,Labidomera,Paropsis,Paropsisterna,Phratora,Phyllocharis,Plagiodera,Platyphora,Proseicela,Pterodunga(Chrysomelinae),Coelomera(Galerucinae), andAcromis,Aspidomorpha,Chelymorpha,Conchyloctenia,Ogdoecosta,OmaspidesandStolas(Cassidinae) are reported to cycloalex although cycloalexy in other taxa remains to be discovered. Other types of aggregations in insects include stigmergy, or the induction of additional labor, and epialexy, or the positioning of conspecifics organisms over the midvein or an elongated aspect of a leaf.
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Chen, Xiang, Susan G. Aiken, Michael J. Dallwitz, and Patrice Bouchard. "Systematic studies of Festuca (Poaceae) occurring in China compared with taxa in North America." Canadian Journal of Botany 81, no. 10 (October 1, 2003): 1008–28. http://dx.doi.org/10.1139/b03-096.
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Members of the genus Festuca in China were studied from an illustrated database developed using the DELTA (DEscription Language for Taxonomy) software package. The database includes the place of valid publication of scientific names; the location of type specimens when known; whether we have examined the type specimens; synonymy; information on habitat, distribution, subgeneric classification, and taxonomic notes; and approximately 200 images. Five subgenera and 58 species including aggregates are recognized. Six taxa are not assigned to a subgenus at this time. Species descriptions of 400–500 words were generated in Chinese and English and are available on the Internet at http://cdelta.ibcas.ac.cn and as a CD-ROM in English and Chinese from the first author. INTKEY has been used to produce parallel and diagnostic descriptions of 120–130 words for 58 species of the genus Festuca for the Flora of China treatment in English. INTKEY and other DELTA programs were used to assess taxa throughout the database and in a detailed study of 11 flat-leaved taxa that appear to have their centre of diversity in China. The awnless taxa from China that were considered belong to the genus Festuca, not Poa. All the flat-leaved Festuca studied are sufficiently morphologically unique to be treated as species distinct from any found in North America. Clustering and phylogenetic methodologies were used to assess subgeneric and sectional classifications. A new section is proposed, Parviglumae sect. nov.Key words: Festuca, Subulatae, DELTA, China, systematics.
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Yue, Hong, Yanyan Zhang, Yanling He, Gehong Wei, and Duntao Shu. "Keystone taxa regulate microbial assemblage patterns and functional traits of different microbial aggregates in simultaneous anammox and denitrification (SAD) systems." Bioresource Technology 290 (October 2019): 121778. http://dx.doi.org/10.1016/j.biortech.2019.121778.
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BARBATO, MATTEO, CLAUDIO BARRÍA, ANDREA BELLODI, SARA BONANOMI, DIEGO BORME, ILIJA ĆETKOVIĆ, FRANCESCO COLLOCA, et al. "The use of fishers’ Local Ecological Knowledge to reconstruct fish behavioural traits and fishers’ perception of conservation relevance of elasmobranchs in the Mediterranean Sea." Mediterranean Marine Science 22, no. 3 (October 14, 2021): 603. http://dx.doi.org/10.12681/mms.25306.
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The Mediterranean Sea has a long-lasting history of fishery exploitation that, together with other anthropogenic impacts, has led to declines in several marine organisms. In particular, elasmobranch populations have been severely impacted, with drastic decreases in abundance and species diversity. Based on their experience, fishers can provide information on marine species occurrence, abundance and behavioural traits on a long-term scale, therefore contributing to research on the poorly studied biological aspects of elusive or rare elasmobranch species. In this study, for the first time, the use of the Local Ecological Knowledge (LEK) of fishers was applied to study the behavioural traits of sharks, rays and skates in 12 FAO-GFCM geographical sub-areas (GSAs) of the Mediterranean Sea. This study found both new insight and proved the reliability of LEK-based catch seasonality, reflecting seasonal movements, by comparing LEK-based findings and available literature on five elasmobranch taxa (Mustelus spp., Squalus acanthias, Raja spp., Myliobatis aquila and Scyliorhinus stellaris) in the Adriatic Sea and 7 taxa (Mustelus spp., Raja spp., Prionace glauca, Scyliorhinus canicula, Torpedo spp., Pteroplatytrygon violacea and Isurus oxyrinchus) in the remaining Mediterranean GSAs. In addition, LEK provided new insights into a novel comprehensive representation of species aggregations (Mustelus spp., S. acanthias, M. aquila and S. canicula) in the sampled GSAs and supplied the first descriptions of the size, number of individuals and sex composition of the aggregations. When the limits and shortcomings of LEK-based research are considered, this methodology can be a complementary and cost-effective tool used to study elasmobranchs in either a data-poor scenario or a scenario in which a baseline is missing. LEK can also be useful for the evaluation and inclusion of fishers’ perceptions on bottom-up management and to provide important evidence for conservation plans.
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Pellegrino, Elisa, Gaia Piazza, Thorunn Helgason, and Laura Ercoli. "Eukaryotes in soil aggregates across conservation managements: Major roles of protists, fungi and taxa linkages in soil structuring and C stock." Soil Biology and Biochemistry 163 (December 2021): 108463. http://dx.doi.org/10.1016/j.soilbio.2021.108463.
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Reiman, Derek, Ahmed Metwally, Jun Sun, and Yang Dai. "Meta-Signer: Metagenomic Signature Identifier based onrank aggregation of features." F1000Research 10 (March 9, 2021): 194. http://dx.doi.org/10.12688/f1000research.27384.1.
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The advance of metagenomic studies provides the opportunity to identify microbial taxa that are associated with human diseases. Multiple methods exist for the association analysis. However, the results could be inconsistent, presenting challenges in interpreting the host-microbiome interactions. To address this issue, we develop Meta-Signer, a novel Metagenomic Signature Identifier tool based on rank aggregation of features identified from multiple machine learning models including Random Forest, Support Vector Machines, Logistic Regression, and Multi-Layer Perceptron Neural Networks. Meta-Signer generates ranked taxa lists by training individual machine learning models over multiple training partitions and aggregates the ranked lists into a single list by an optimization procedure to represent the most informative and robust microbial features. A User will receive speedy assessment on the predictive performance of each ma-chine learning model using different numbers of the ranked features and determine the final models to be used for evaluation on external datasets. Meta-Signer is user-friendly and customizable, allowing users to explore their datasets quickly and efficiently.
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Tennakoon, Danushka S., Nimali I. de Silva, Sajeewa S. N. Maharachchikumbura, Darbhe J. Bhat, Jaturong Kumla, Nakarin Suwannarach, and Saisamorn Lumyong. "Exploring More on Dictyosporiaceae: The Species Geographical Distribution and Intriguing Novel Additions from Plant Litter." Diversity 15, no. 3 (March 10, 2023): 410. http://dx.doi.org/10.3390/d15030410.
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Five fungal taxa collected from plant litter in Chiang Mai province, Thailand, are described with illustrations. The maximum likelihood, maximum parsimony, and Bayesian analyses of combined loci of the internal transcribed spacer (ITS), large subunit nuclear ribosomal DNA (LSU), and translation extension factor 1-α (tef1-α) region were used for phylogeny analyses. Dictyocheirospora acaciae is introduced as a new species from Acacia dealbata. Based on size differences in conidiomata, conidia, and DNA sequence data, it is separated from the other species in the genus. Four new host records, Dictyocheirospora garethjonesii, Di. taiwanense, Dictyosporium digitatum, and Pseudocoleophoma zingiberacearum are also reported from Bismarkia nobilis, Ficus benjamina, Cyperus aggregatus, and Hedychium spicatum, respectively. Detailed descriptions, microphotographs, and phylogenetic information were provided, and all the species were compared to similar taxa. It is noted that there is still a necessity for a collective worldwide account of the distribution of Dictyosporiaceae species. Therefore, we compiled the geographical distributions and host species associations of all the so far known Dictyosporiaceae species and discussed them here.
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Francis, Roxane J., Mitchell B. Lyons, Richard T. Kingsford, and Kate J. Brandis. "Counting Mixed Breeding Aggregations of Animal Species Using Drones: Lessons from Waterbirds on Semi-Automation." Remote Sensing 12, no. 7 (April 7, 2020): 1185. http://dx.doi.org/10.3390/rs12071185.
Full textAbstract:
Using drones to count wildlife saves time and resources and allows access to difficult or dangerous areas. We collected drone imagery of breeding waterbirds at colonies in the Okavango Delta (Botswana) and Lowbidgee floodplain (Australia). We developed a semi-automated counting method, using machine learning, and compared effectiveness of freeware and payware in identifying and counting waterbird species (targets) in the Okavango Delta. We tested transferability to the Australian breeding colony. Our detection accuracy (targets), between the training and test data, was 91% for the Okavango Delta colony and 98% for the Lowbidgee floodplain colony. These estimates were within 1–5%, whether using freeware or payware for the different colonies. Our semi-automated method was 26% quicker, including development, and 500% quicker without development, than manual counting. Drone data of waterbird colonies can be collected quickly, allowing later counting with minimal disturbance. Our semi-automated methods efficiently provided accurate estimates of nesting species of waterbirds, even with complex backgrounds. This could be used to track breeding waterbird populations around the world, indicators of river and wetland health, with general applicability for monitoring other taxa.
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Fisher, Heidi S., Luca Giomi, Hopi E. Hoekstra, and L. Mahadevan. "The dynamics of sperm cooperation in a competitive environment." Proceedings of the Royal Society B: Biological Sciences 281, no. 1790 (September 7, 2014): 20140296. http://dx.doi.org/10.1098/rspb.2014.0296.
Full textAbstract:
Sperm cooperation has evolved in a variety of taxa and is often considered a response to sperm competition, yet the benefit of this form of collective movement remains unclear. Here, we use fine-scale imaging and a minimal mathematical model to study sperm aggregation in the rodent genus Peromyscus . We demonstrate that as the number of sperm cells in an aggregate increase, the group moves with more persistent linearity but without increasing speed. This benefit, however, is offset in larger aggregates as the geometry of the group forces sperm to swim against one another. The result is a non-monotonic relationship between aggregate size and average velocity with both a theoretically predicted and empirically observed optimum of six to seven sperm per aggregate. To understand the role of sexual selection in driving these sperm group dynamics, we compared two sister-species with divergent mating systems. We find that sperm of Peromyscus maniculatus (highly promiscuous), which have evolved under intense competition, form optimal-sized aggregates more often than sperm of Peromyscus polionotus (strictly monogamous), which lack competition. Our combined mathematical and experimental study of coordinated sperm movement reveals the importance of geometry, motion and group size on sperm velocity and suggests how these physical variables interact with evolutionary selective pressures to regulate cooperation in competitive environments.
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Zexer, Nerya, and Rivka Elbaum. "Unique lignin modifications pattern the nucleation of silica in sorghum endodermis." Journal of Experimental Botany 71, no. 21 (March 9, 2020): 6818–29. http://dx.doi.org/10.1093/jxb/eraa127.
Full textAbstract:
Abstract Silicon dioxide in the form of hydrated silica is a component of plant tissues that can constitute several percent by dry weight in certain taxa. Nonetheless, the mechanism of plant silica formation is mostly unknown. Silicon (Si) is taken up from the soil by roots in the form of monosilicic acid molecules. The silicic acid is carried in the xylem and subsequently polymerizes in target sites to silica. In roots of sorghum (Sorghum bicolor), silica aggregates form in an orderly pattern along the inner tangential cell walls of endodermis cells. Using Raman microspectroscopy, autofluorescence, and scanning electron microscopy, we investigated the structure and composition of developing aggregates in roots of sorghum seedlings. Putative silica aggregation loci were identified in roots grown under Si starvation. These micrometer-scale spots were constructed of tightly packed modified lignin, and nucleated trace concentrations of silicic acid. Substantial variation in cell wall autofluorescence between Si+ and Si– roots demonstrated the impact of Si on cell wall chemistry. We propose that in Si– roots, the modified lignin cross-linked into the cell wall and lost its ability to nucleate silica. In Si+ roots, silica polymerized on the modified lignin and altered its structure. Our work demonstrates a high degree of control over lignin and silica deposition in cell walls.
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Dovčiak, Martin, Charles B. Halpern, James F. Saracco, Shelley A. Evans, and Denise A. Liguori. "Persistence of ground-layer bryophytes in a structural retention experiment: initial effects of level and pattern of overstory retention." Canadian Journal of Forest Research 36, no. 11 (November 1, 2006): 3039–52. http://dx.doi.org/10.1139/x06-168.
Full textAbstract:
We examined first-year responses of forest-floor bryophytes to structural retention harvests at four locations in western Washington. Treatments represented a range of retention levels (100%, 75%, 40%, and 15% of original basal area) and spatial patterns (dispersed vs. aggregated in 1 ha patches). Declines in bryophyte cover and species' frequencies were comparably large at 40% and 15% retention. Retention pattern had little effect on the magnitude of decline, although declines in richness tended to be greater in aggregated treatments. Changes in cover were small within forest aggregates (comparable to controls). However, richness declined relative to controls within aggregates at 15% retention; rarer taxa in these exposed patches may be susceptible to edge effects. Declines in species' frequencies and richness were consistently greater in "clear-cut" areas of aggregated treatments than in dispersed retention; liverworts were particularly sensitive to harvest. In cut areas, bryophytes responded positively to cover of understory vegetation and negatively to logging slash. The positive correlation of richness (but not cover) to tree basal area may reflect the contribution of tree boles to persistence of rarer corticolous species. Our results suggest that conservation of bryophytes in forests managed with structural retention will require large retention patches and dispersed trees at levels considerably higher than current retention standards.