Specific Assemblages Research Articles

Synthetic Training Data and the Reconfiguration of Surveillant Assemblages

Synthetic training data promise considerable performance improvements in machine learning (ML) surveillance tasks, including such applications as crowd counting, pedestrian tracking, and face recognition. In this context, synthetic training data constitute techno-fixes primarily by virtue of acting as “edge cases”—data that are hard to come by in the “real world” yet straightforward to produce synthetically—which are used to enhance ML systems’ resilience. In this dialogue paper, I mobilize Haggerty and Ericson’s (2000) concept of the surveillant assemblage to argue that synthetic training data raise well-known, entrenched surveillance issues. Specifically, I contend that conceptualizing synthetic data as but one component of larger surveillant assemblages is analytically meaningful because it challenges techno-deterministic imaginaries that posit synthetic data as fixes to deep-rooted surveillance issues. To exemplify this stance, I draw from several examples of how synthetic training data are already used, illustrating how they may both intensify the disappearance of disappearance and contribute to the leveling of hierarchies of surveillance depending upon the surveillant assemblage that they reconfigure. Overall, this intervention urges surveillance studies scholarship to attend to how synthetic data reconfigure specific surveillant assemblages, with both problematic and emancipatory implications.

Organic Matter Composition and Water Stoichiometry Are Main Drivers of Heterotrophic Nitrate Uptake in Mediterranean Headwater Streams

AbstractHeterotrophic bacteria can contribute to improve stream water quality by taking up nitrate (NO3−) from the water column, although microbial demand for this nutrient is usually lower than for other inorganic nitrogen (N) forms, such as ammonium. Heterotrophic NO3− uptake has been related to the availability of dissolved organic carbon (DOC) relative to nutrients (i.e., DOC: nutrients ratios). Yet, how dissolved organic matter (DOM) composition and specific microbial assemblages influence NO3− uptake remains poorly understood. We conducted laboratory incubations to investigate heterotrophic NO3− uptake kinetics in 9 Mediterranean freshwater ecosystems, primarily headwater streams, exhibiting wide variation in DOC:NO3 ratios (from 1.5 to 750). Moreover, we characterized DOM composition using spectroscopic indexes and its degradation via a reactivity continuum model approach. Microbial community composition and functioning were assessed by analyzing extracellular enzymatic activities and the potential abundance of N‐cycling genes. Our results revealed that NO3− uptake rates (kNO3) were positively related with DOC:NO3 ratios (r2 = 0.4) and to NO3:SRP ratios as well (r2 = 0.6). Furthermore, kNO3 was negatively correlated to the humification index (r2 = 0.7), suggesting that a higher proportion of humic‐like compounds slow down heterotrophic NO3− uptake. A partial least squares regression model (PLS) pinpointed that DOC and nutrient stoichiometry, DOM composition and reactivity, and microbial composition and activity collectively contributed to explain the variability in kNO3 observed across treatments. Our findings suggest that heterotrophic NO3− uptake may show significant responsiveness to shifts toward more labile DOM sources and nutrient imbalances induced by global change.

“Dengue fever is not just urban or rural: Reframing its spatial categorization.”

Infectious diseases exploit niches that are often spatially defined as urban and/or rural. Yet spatial research on infectious diseases often fails to define “urban” and “rural” and how these contexts might influence their epidemiology. We use dengue fever, thought to be mostly an urban disease with rural foci, as a device to explore local definitions of urban and rural spaces and the impact of these spaces on dengue risk in the provinfine urban and rural locales. Interviews conducted from 2019 to 2021 with 71 residents and 23 health personce of Esmeraldas, Ecuador. Ecuador, like many countries, only uses population size and administrative function to denel found that they identified the availability of basic services, extent of their control over their environment, and presence of underbrush and weeds (known in Ecuador as monte and maleza and conceptualized in this paper as natural disorder) as important links to their conceptions of space and dengue risk. This broader conceptualization of space articulated by local residents and professionals reflects a more sophisticated approach to characterizing dengue risk than using categories of urban and rural employed by the national census and government. Rather than this dichotomous category of space, dengue fever can be better framed for health interventions in terms of specific environmental features and assemblages of high-risk spaces. An understanding of how community members perceive risk enhances our ability to collaborate with them to develop optimal mitigation strategies.

Endophytic consortium exhibits varying effects in mitigating cadmium toxicity in rice cultivars with distinct cadmium accumulation capacities

Cadmium (Cd)-contaminated rice is the main source of Cd exposure that threatens food safety and human health. While plant growth-promoting bacteria (PGPB) have been reported to reduce Cd toxicity in rice, the effect of endophytic consortium is less understood compared to the single strain. Here, we reported that the PGPB consortium consisting of Cd-tolerant endophytic bacteria Pseudomonas sp. 4N2 and Bacillus sp. TB1 increased extracellular polymeric substance secretion and demonstrated a higher Cd removal rate compared to individual 4N2 and TB1. Further, two rice cultivar, namely the low-Cd-accumulating (LA) cultivar 728B and the high-Cd-accumulating (HA) cultivar BB, were inoculated with the 4N2-TB1 consortium. As expected, the consortium had a more pronounced effect on 728B, from which the endophytic bacteria were screened. The 4N2-TB1 consortium was found to facilitate the growth of rice seedlings and enhance their antioxidation activity. Moreover, the consortium significantly reduced Cd transfer coefficient from root to shoot through Cd immobilization in rice roots, resulting in a reduction from 30 % to 6 % in 728B and from 31 % to 13 % in BB. Furthermore, alpha-diversity analysis indicated an increased diversity and richness of the root bacterial community after 4N2-TB1 inoculation. Also, redundancy analysis confirmed a positive correlation between rice biomass and Cd content with a specific assemblage of bacteria including Bacillus and Leifsonia. These results demonstrated that the 4N2-TB1 consortium may alleviate Cd stress in rice cultivars through recruiting PGPB and Cd-binding bacteria on the root surface, thus strengthening the immobilization of Cd in rice roots.

Planners Becoming Visualizers in the Mediatized World: Actor-Network Analysis of Cairo’s Street Billboards

While visual communication is crucial in urban planning, there is a gap in understanding how dominant narratives and visuals affect professional planning practice and planners’ roles, particularly in mediatized urban environments. This study addresses this gap by examining street billboards in Cairo to understand how planning visualizations contribute to the restructuring of the planning profession. It explores how these visual tools shape the practice and roles of urban planners, who are increasingly becoming visualizers. Employing actor-network theory, the study traces the relationships between billboards, planners, and other network actors. The primary research question is: How and why does the use of planning visualizations (billboards) restructure the profession of planning, including planning practice and the roles of planners? Utilizing a qualitative exploratory methodology, the study focuses on billboards along Cairo’s 6th of October Bridge. Data were analyzed through visual and content analysis of 209 billboards to understand their language, content, patterns, and geo-positioning. The analysis revealed that billboards in Cairo significantly impact urban landscapes and the visual culture of urbanization, often promoting exclusive real estate projects to a socio-economic elite. The research highlights the dilemmas in the changing professional roles of planners within a mediatized world and underscores the need for more inclusive planning practices. By employing actor-network theory, the study provides a nuanced understanding of the complex relationships that shape and are shaped by the visual culture of urban planning, offering insights into how planners can navigate and influence these dynamics for more equitable urban development.

Producing accountability with autonomy in Denmark and England: the analytical potential of assemblage theory with critical realism in comparative education

ABSTRACT School autonomy with accountability (SAWA) reforms have developed in diverse forms in Northern Europe. Following processes of decentralization to the municipal and school levels, quality assurance and inspection became key to the test-based accountability agendas of Denmark and England respectively. With an abductive approach, we explore the epistemological potential of a hybrid theoretical framework, which combines assemblage theory with critical realism, to analyze the production stories of these two policy instruments. Drawing on data from an international comparative research project, and more recent policy document analyses, we examine the arrangement of social entities – discourses, instruments, technologies, artefacts, and actors – that led to particular accountability outcomes within these specific educational assemblages. We argue that, despite distinctions in their social entities, the dominant state assemblages of accountability in Denmark and England have been captured by the global SAWA and capitalist assemblages at distinct times. Although school actors are incorporated into, and antagonistic towards, the state assemblages, change is limited due to the resilience of the underlying logic of epistemic governance and the desire to improve educational standards for a global knowledge economy. We conclude briefly with an assessment of the utility of the hybrid framework to the comparison of SAWA.

Influence of Drought Stress on the Rhizosphere Bacterial Community Structure of Cassava (Manihot esculenta Crantz).

Drought presents a significant abiotic stress that threatens crop productivity worldwide. Rhizosphere bacteria play pivotal roles in modulating plant growth and resilience to environmental stresses. Despite this, the extent to which rhizosphere bacteria are instrumental in plant responses to drought, and whether distinct cassava (Manihot esculenta Crantz) varieties harbor specific rhizosphere bacterial assemblages, remains unclear. In this study, we measured the growth and physiological characteristics, as well as the physical and chemical properties of the rhizosphere soil of drought-tolerant (SC124) and drought-sensitive (SC8) cassava varieties under conditions of both well-watered and drought stress. Employing 16S rDNA high-throughput sequencing, we analyzed the composition and dynamics of the rhizosphere bacterial community. Under drought stress, biomass, plant height, stem diameter, quantum efficiency of photosystem II (Fv/Fm), and soluble sugar of cassava decreased for both SC8 and SC124. The two varieties' rhizosphere bacterial communities' overall taxonomic structure was highly similar, but there were slight differences in relative abundance. SC124 mainly relied on Gamma-proteobacteria and Acidobacteriae in response to drought stress, and the abundance of this class was positively correlated with soil acid phosphatase. SC8 mainly relied on Actinobacteria in response to drought stress, and the abundance of this class was positively correlated with soil urease and soil saccharase. Overall, this study confirmed the key role of drought-induced rhizosphere bacteria in improving the adaptation of cassava to drought stress and clarified that this process is significantly related to variety.

‘Where are you from?’ The affective and emotional dimensions of an ambiguous event of everyday racism

This article discusses the various affective and emotional dimensions of how racialised individuals understand and cope with the ambiguous question of ‘Where are you (really) from?’ Theoretically, the article argues that people do not necessarily ‘comprehend’ racism but sense it, and that it is through affects and being affected that they understand the nature of an encounter. Empirically, the article is based on 21 in-depth interviews conducted with Black Germans, and it analyses respondents’ reflections on and ‘emotion memories’ of being asked the question of ‘Where are you from?’ Only a few respondents said that they had consciously decided to always regard the question as ‘normal’ and thus to ‘switch off their sensitivity’. Overall, when asked this question, interviewees relied on ‘affective thinking-feeling’ to determine whether there was racism to be sensed. By analysing respondents’ narratives of particular episodes in which they were asked the question, the article proposes that a specific assemblage and affective intensities are the main conditions for immediately sensing racism in and through the question. In addition, the article discusses interviewees’ range of response options and why and when respondents may engage in ‘emotion work’ when responding to the question. The article concludes by highlighting different types of emotions associated with sensing racism through the question, particularly the emotions of unease, discomfort, and disappointment that can lead to feelings of non-belonging.

A geochemical model for the transformation of gabbro into vesuvianite-bearing rodingite

Rodingite is a Ca-rich and Si-poor metasomatic rock commonly occurring in association with serpentinites. This rock is characterized by specific mineral assemblages consisting of hydrated garnet, diopside, vesuvianite, epidote-zoisite, chlorite, or prehnite. However, natural rodingites are significantly heterogeneous in mineral composition and vesuvianite occurs only in some extensively rodingitized rocks. Major factors controlling the mineral diversity as well as details on fluid-rock interactions leading to the evolution of mineral and chemical composition during rodingitization have not yet been fully constrained. In this work, we use PHREEQC software to present a geochemical model for the transformation of a mafic rock into vesuvianite-bearing rodingite at a temperature of 300 °C. Through these simulations, we investigate the effect of fluid composition and progress of the metasomatic process on rodingite formation. Our results show that rodingitization requires an open system with a high input of hydrothermal fluid. Additionally, a decrease in the Si/Ca ratio in the metasomatized rock is correlated to an increase in the volume of incoming fluid. Whole rock chemical and mineral composition in natural rodingites are well reproduced by the model. Furthermore, the diversity of mineral parageneses results mainly from different degrees of transformation and only to a lesser extent to the chemical composition of hydrothermal fluid or protolith. The hydrothermal fluid doesn't need to be especially rich in calcium to transform a mafic rock into rodingite, but it must be low in magnesium, silicon, and have a high pH, which is naturally controlled by serpentinization of surrounding ultramafic rocks.

A numerical model for the quantification of fluid inclusion property variations caused by heterogeneous entrapment and post-entrapment modifications in the H2O-NaCl system

The primary geological conditions for hydrothermal systems can be reconstructed using fluid inclusions, which generally requires that fluid inclusions trapped a single homogeneous phase and experienced no mass and volume changes after entrapment (Roedder's Rules). However, heterogeneous entrapment and post-entrapment modifications have been frequently identified in fluid inclusion studies, making the recovery of primary fluid properties from fluid inclusion data challenging or impossible. In this study, we constructed a specific tool, FlincPro, for the calculations of ideal and nonideal Fluid inclusion Properties in the H2O-NaCl system (ideal here refers to fluid inclusions that adhere to Roedder's Rules). Multiple modules have been developed to quantify the variations of fluid inclusion properties caused by heterogeneous entrapment, volume contraction/expansion, and water loss. The developed software illustrates possibilities in the variation of fluid inclusions in a specific assemblage with the input of a certain starting point.We found that compositions of the vapor endmember fluid are more significantly affected by heterogeneous entrapment than the liquid endmember, as the latter may have several orders of magnitude higher salinity and density. Homogenization pressure and temperature of halite-bearing fluid inclusions trapped on the halite liquidus will increase sharply with the addition of halite, but the homogenization behavior will not be changed. Volume contraction/expansion are effective ways to change the homogenization behaviors, especially for high salinity fluid inclusions. Water loss is not likely to cause the homogenization behavior change from total homogenization by vapor disappearance to total homogenization by halite dissolution for a halite-bearing fluid inclusion without additional volume contraction. Low-salinity and low-density fluid inclusions with total homogenization temperature around the critical temperature of water are least affected by post-entrapment modifications. Therefore, the interpretation of fluid inclusions formation depends on more parameters, e.g., petrographic observations, density and composition variations in fluid inclusion assemblages, and geological information, than only microthermometric data.

Nitrogen-fixing bacterial communities differ between perennial agroecosystem crops.

Biocrusts, common in natural ecosystems, are specific assemblages of microorganisms at or on the soil surface with associated microorganisms extending into the top centimeter of soil. Agroecosystem biocrusts have similar rates of nitrogen (N) fixation as those in natural ecosystems, but it is unclear how agricultural management influences their composition and function. This study examined the total bacterial and diazotrophic communities of biocrusts in a citrus orchard and a vineyard that shared a similar climate and soil type but differed in management. To contrast climate and soil type, these biocrusts were also compared with those from an apple orchard. Unlike natural ecosystem biocrusts, these agroecosystem biocrusts were dominated by proteobacteria and had a lower abundance of cyanobacteria. All of the examined agroecosystem biocrust diazotroph communities were dominated by N-fixing cyanobacteria from the Nostocales order, similar to natural ecosystem cyanobacterial biocrusts. Lower irrigation and fertilizer in the vineyard compared with the citrus orchard could have contributed to biocrust microbial composition, whereas soil type and climate could have differentiated the apple orchard biocrust. Season did not influence the bacterial and diazotrophic community composition of any of these agroecosystem biocrusts. Overall, agricultural management and climatic and edaphic factors potentially influenced the community composition and function of these biocrusts.

Artists’ publishing: Sites of affective experimentation

The past few decades have seen conversations around code and language exponentially intensify, with the advent of social media – X/Twitter, TikTok, Instagram and Facebook – and artificial intelligence, ChatGPT and so on. In this article, Ami Clarke makes the case for artists’ publishing as a site of affective experimentation that emerges from very specific human and technological assemblages throughout history. A posthuman reading reveals the unreliable narrator, the unstable text, fluidity and multiplicity and other emergent properties, indicative of a subjectivity that emerges in synthesis with its environment, revealing artists’ publishing as a radical site of change. This article focuses specifically on publishing as process – the idea of processual works that critique through their production and distribution, and that come out of the frameworks inherent to publishing and early networked culture, and hence the dissemination of ideas central to this.

Thermal tolerance does not explain the altitudinal segregation of lowland and alpine aquatic insects

Elevation gradients provide powerful study systems for examining the influence of environmental filters in shaping species assemblages. High-mountain habitats host specific high-elevation assemblages, often comprising specialist species adapted to endure pronounced abiotic stress, while such harsh conditions prevent lowland species from colonizing or establishing. While thermal tolerance may drive the altitudinal segregation of ectotherms, its role in structuring aquatic insect communities remains poorly explored. This study investigates the role of thermal physiology in shaping the current distribution of high-mountain diving beetles from the Sierra Nevada Iberian mountain range and closely related lowland species. Cold tolerance of five species from each altitudinal zone was measured estimating the supercooling point (SCP), lower lethal temperature (LLT) and tolerance to ice enclosure, while heat tolerance was assessed from the heat coma temperature (HCT). Alpine species exhibited wider fundamental thermal niches than lowland species, likely associated with the broader range of climatic conditions in high-mountain areas. Cold tolerance did not seem to prevent lowland species from colonizing higher elevations, as most studied species were moderately freeze-tolerant. Therefore, fundamental thermal niches seem not to fully explain species segregation along elevation gradients, suggesting that other thermal tolerance traits, environmental factors, and biotic interactions may also play important roles.

Consistent Symbiodiniaceae community assemblage in a mesophotic-specialist coral along the Saudi Arabian Red Sea

IntroductionThe Red Sea is a narrow rift basin characterized by latitudinal environmental gradients which shape the diversity and distribution of reef-dwelling organisms. Studies on Symbiodiniaceae associated with select hard coral taxa present species- specific assemblages and concordant variation patterns from the North to southeast Red Sea coast at depths shallower than 30 m. At mesophotic depths, however, algal diversity studies are rare. Here, we characterize for the first-time host-associated algal communities of a mesophotic specialist coral species, Leptoseris cf. striatus, along the Saudi Arabian Red Sea coast.MethodsWe sampled 56 coral colonies spanning the eastern Red Sea coastline from the Northern Red Sea to the Farasan Banks in the South, and across two sampling periods, Fall 2020 and Spring 2022. We used Next Generation Sequencing of the ITS2 marker region in conjunction with SymPortal to denote algal assemblages.Results and discussionOur results show a relatively stable coral species-specific interaction with algae from the genus Cladocopium along the examined latitudinal gradient, with the appearance, in a smaller proportion, of presumed thermally tolerant algal taxa in the genera Symbiodinium and Durusdinium during the warmer season (Fall 2020). Contrary to shallow water corals, our results do not show a change in Symbiodiniaceae community composition from North to South in this mesophotic specialist species. However, our study highlights for the first time that symbiont communities are subject to change over time at mesophotic depth, which could represent an important phenomenon to address in future studies.

Younger Dryas and Early Holocene ice‐margin dynamics in northwest Russia

Younger Dryas and Early Holocene ice‐margin dynamics in northwest Russia

The generic Middle Stone Age: fact or fiction?

ABSTRACT Recent decades have seen a surge of interest in the Middle Stone Age (MSA) as it constitutes the archaeological background to the early evolution of Homo sapiens. Research primacy has been given to rare regional and temporal signatures of MSA technological diversity and material culture, typically in open grassland or sparse savanna regions. These include, for example, the Still Bay, Howiesons Poort, Lupemban and Aterian, all of which can be seen as specific variants of the MSA. Archaeological assemblages apparently lacking distinctive features have received little attention in their own right. Such occurrences can be subsumed under the informal term of a more ‘generic’ MSA. The marginalisation of this material culture is problematic as it dominates the MSA record. The apparent continuity and commonality of generic MSA elements over large spatial and temporal scales also raise manifold questions about the early evolution of our species. As such, a ‘generic’ MSA might be perceived as the common technological and material substrate of early Homo sapiens behaviour and culture. At the same time, we lack quantitative studies that justify subsuming close to 300,000 years of material culture into a single category. This special issue of Azania is based on a symposium at the Sixteenth Congress of the PanAfrican Archaeological Association of Prehistory and Related Studies in Zanzibar (Tanzania) that brought together researchers working in different African regions to scrutinise apparently ‘non-specific’ MSA lithic assemblages across time and space, evaluating their commonality and relevance on different chronological and geographical scales. The six articles in this issue span comparative quantitative studies within and across regions, methodological and theoretical advances to reach these goals and the integration of palaeoecological data. A common interest lies in understanding but also testing the validity of using a ‘generic’ MSA and the general relevance of more specific or generic technological assemblages in the wider framework of modern human cultural and biological evolution.

Petroleum’s Influence on the Aquatic Environment

Aquifer, rivers, or lakes are frequently employed as the local sources of water that the petroleum industry uses to drill and hydraulically fracture wells, refine and process petroleum, and create electricity in certain natural gas-based power plants. Oil residues, chemicals from hydraulic fracturing and drilling fluids, and naturally occurring pollutants from the rocks themselves may all be present in the water that is generated along with petroleum. It is also frequently naturally salty. The environmental effects of petroleum activities may change a range of ecological characteristics, such as biodiversity, biomass, and productivity, which may then affect specific species, populations, assemblages, or ecosystems. There are two basic types of long-term and short-term impacts of petroleum contamination in water. The difficulties produced by point pollution in aquatic ecosystems have come to light due to the impact of petroleum compounds on living organisms in aquatic environments.

Comparison of microbial community assemblages in the rhizosphere of three Amaranthus spp.

Weed management remains a major challenge in cropping systems worldwide, with rising interest in ecological based approaches that can be integrated with herbicide use. Soil microbial communities may play important, yet undiscovered, roles in weed success. Little is known about the rhizosphere communities associated with weeds like Amaranthus, commonly known as pigweeds, and considered some of the most problematic weeds in agricultural systems. In a greenhouse experiment that allowed controlled plant growth conditions and a high number of individual plant specimens to analyze for statistical robustness (n = 8 per species), we show that specific bacterial assemblages form in the rhizospheres of A. retroflexus L. (redroot pigweed), A. palmeri S. Watson (Palmer amaranth), and A. tuberculatus (Moq.) J. D. Sauer (waterhemp). Using a relatively rapid and easy approach of T-RFLP community profiling of the 16S rRNA genes, distinct assemblages corresponded to plant species (PERMANOVA F = 14.776, p = 0.001), and further within each species, similar communities (F = 11.449, p = 0.001) were associated with three rhizosphere soil fractions taken in increasing distances away from the root tissue. These results provide the first solid basis for distinct plant-microbe relationships within three closely related Amaranthus species, warranting closer examination of the identities and function of the microorganisms that appear to be selectively recruited from the extant soil community. More intensive efforts to obtain the microbial taxonomic identities via sequencing are underway that can lead to further detailed studies to elucidate important functional plant-microbe interactions that may associate with weed success. Such data provides underlying key information that may ultimately exploit weed-microbe interactions in development of new integrated weed control tactics.

Microscopic and molecular diagnoses of Giardia duodenalis in pet animals in Babylon Province, Iraq.

The breeding of pet animals, especially dogs and cats, in Iraq has increased recently. However, no epidemiological or molecular data exist regarding Giardia duodenalis infection in pet animals, particularly in Babylon Province. Therefore, this study aimed to detect G. duodenalis and its genotypes in pets using microscopic and molecular techniques. For microscopic examination, 150 pet fecal samples (dogs = 75, cats = 75) were examined from October 1, 2022, to March 30, 2023. Fourteen isolates of G. duodenalis (7 per host) were genetically characterized using SSUrDNA gene sequencing. Microscopic examination revealed that the rates of G. duodenalis infection was 14.67% (11/75) and 12% (9/75) in dogs and cats, respectively. According to sex, the infection rate in dogs was 22.22% (8/36) for males and 7.69% (3/39) for females. Conversely, the infection rate in cats was 5.56% (2/36) for males and 17.95% (7/39) for females. The highest infection rates were recorded for animals under 6 months of age, with 16.67% (3/18) for dogs and 27.27% (3/11) for cats. In rural areas, the infection rate was higher than that in urban areas, with 17.65% (6/34) in dogs and 13.89% (5/36) in cats. For the molecular diagnosis, 14 isolates of G. duodenalis (7 per host) were genetically characterized using SSUrDNA gene sequencing. In dogs, the findings revealed specific genotypes, with D at 3/7 (42.86%) and C at 2/7 (28.57%). In addition, zoonotic genotype A was found in 2/7 (28.57%) of dogs. In cats, the specific assemblage F was present in 4/7 (57.14%), while zoonotic genotype A was found in 3/7 (42.86%). This study is considered the first in Babylon Province to detect G. duodenalis genotypes in pet animals (dogs and cats), as some have zoonotic genotypes that could transmit infections to humans. The results of this study illustrate the epidemiological importance of this parasite in this region.

Paleontology, Stratigraphy and Biogeography of the Late Precambrian and Phanerozoic Formations of Russia

Abstract —This special issue is dedicated to discussing the possibility of the stage division of the Vendian system, specifically, a composite section of the Siberian Platform is proposed as a stratigraphic standard. For the Ordovician system of the Siberian Platform and Northeastern Russia, certain changes in stratigraphic charts are proposed, nomenclative issues and different variants of correlations of regional horizons with the General Stratigraphic Scale (GSS) of Russia are considered. A geochemical analysis of Bajocian and Bathonian belemnite rostra of Arctic Siberia was carried out and for the first time a comprehensive C, O, and Sr isotope characterization of the sections was obtained, making it possible to propose a comparison of the studied sections with the European standard and to develop paleogeographic models. Comprehensive studies of the Upper Jurassic and Lower Cretaceous series of the Anabar Bay deposits (Laptev Sea) led to an improved biostratigraphic division for this reference section and to the identification of the levels for interregional and global correlation. The magnetostratigraphic division of the Jurassic–Cretaceous boundary interval and its comparison with the Tethyan regions are discussed. Taking into account biostratigraphic data, the δ13Corg variation curve can also serve as a correlation tool. The clinoform structure of Upper Jurassic strata was revealed in the northwest of the Anabar–Khatanga depression, based on the interpretation of seismic profiles calibrated against studied sections. The formation of this complex allows us to consider this stage as the initiation of the Verkhoyan orogeny in this folded area. Analysis of variations in the thickness of sediments allows us to deduce that intense tectonic-sedimentary processes took place during the Late Jurassic epoch, along with subsidence of the bed of the sedimentary basin. Analysis of a specific assemblage of lacustrine fossils from the reference section of the upper part of the Lower Cretaceous series of Transbaikalia and of published data showed that this fossil assemblage was widespread in East Asia. Biofacies analysis made it possible to reconstruct the paleoenvironments of this time.