Point Information Research Articles

Regularities of variability in the anatomical structure of the left atrium in persons of different body types

Attention of cardiac surgeons and arrhythmologists are the ostia of the pulmonary veins, which are the place of the formation of trigger points during the development of atrial fibrillation. Data on the variability of the anatomical structure of the left atrium are scarce and are often contradictory, which makes it relevant to study the variability of the structure of the left atrium in the aspect of constitutional anatomy. Purpose of the study: to establish patterns of variability in the structure of the left atrium, taking into account body type. Materials and methods: The study is based on an analysis of the results of contrast-enhanced MSCT of the heart in 105 apparently healthy individuals. Results: Analyzing the data obtained on the types of confluence of the pulmonary veins (PV) into the left atrium, it was found that in individuals of all body types, the flow of the 4-ostia pulmonary veins into the cavity of the left vertex occurs in the largest percentage of cases. Among the examined individuals, the following 7 variants of the anatomical structure of the left atrium with different frequencies of occurrence were identified: 1) typical confluence of the PV in combination with the oval shape of the orifice of the left appendage; 2) typical confluence of the PV in combination with the round shape of the mouth of the left atrium (LA) appendage; 3) confluence of the PV with a common collector on the left side in combination with the round shape of the mouth of the LA appendage; 4) confluence of the PV with a common collector on both sides in combination with the oval shape of the mouth of the LA appendage; 5) confluence of the PV with a common collector on both sides in combination with the round shape of the mouth of the LA appendage; 6) typical confluence of the PV in combination with the accessory pulmonary vein and the oval shape of the orifice of the LA appendage; 7) typical confluence of the PV in combination with the accessory pulmonary vein and the round shape of the auricle.

Rate of Force Development During a Handgrip Task Is Correlated with the Post-Impact Ball Speed of the Flat Serve

The aim of the present research was to test the hypothesis that rate of force development (RFD) during a handgrip task of the dominant arm in three different positions is associated with maximal post-impact ball speed of flat serve (PIBS). Altogether 23 elite junior boys (aged 14.84 ± 2.47 years; weight 59.51 ± 13.83 kg; height 170.47 ± 16.34 cm) tennis players participated in the study. To assess the maximal voluntary contraction (MVC) and RFD during the task, four handgrip tests and a serve test were applied to estimate PIBS. Spearman’s rank correlation showed a significant positive correlation between RFD of dominant arm in each three position and PIBS (r = 0.82–0.86; p < 0.001). A very large, significantly positive correlation was also found between MVC of the dominant arm and PIBS (r = 0.88; p < 0.01). The result of the present study indicated that rapid force generation of muscles in the forearm and wrist may probably play a role in the formation of a stable contact point, and it is in connection with PIBS. It is in contrast to the slow maximal force exertion that much rather characterizes the general strength state of players. Therefore, measurement of the RFD during a handgrip task is suggested in the testing session of the flat serve of junior tennis players.

An early cladoxylopsid with complex vascular architecture: Paracladoxylon kespekianum gen. et sp. nov. from the Lower Devonian (Emsian) of Quebec, Canada.

Cladoxylopsids, one of the first lineages with complex organization to rise from the plexus of structurally simple plants that comprised the earliest euphyllophyte floras, are moniliformopsid euphyllophytes. They formed Earth's earliest forests by the Middle Devonian and are thought to have given rise to the equisetopsids and probably some fern lineages. The Lower Devonian (Emsian) Battery Point Formation (Quebec, Canada) contains previously unrecognized cladoxylopsids preserved anatomically. One of these provides new data on structural evolution among euphyllophytes and is described here. The anatomy and morphology of permineralized axes of the new plant were studied with light and electron microscopy on sections produced using the cellulose acetate peel technique. Morphological comparisons and phylogenetic analysis were used for taxonomic placement of the plant. The plant represents a new species, Paracladoxylon kespekianum Chu et Tomescu, gen. et sp. nov., that has tracheids with modern-looking bordered pits and the complex cauline vascular architecture characteristic of the genus Cladoxylon. Its dissected ultimate appendages have complex regular taxis and a pattern of vascularization that suggests bilateral symmetry. Paracladoxylon kespekianum is one of the largest Early Devonian euphyllophytes, among the oldest representatives of the cladoxylopsid group, and older than any species of the closely related Cladoxylon by at least 35 million years. It is also one of the oldest anatomically preserved representatives of the cladoxylopsid group. Its anatomical organization pushes the rise of complex vascular architecture among moniliformopsid euphyllophytes deeper in time than previously recognized.

Studying the Defects in Spinel Compounds: Discovery, Formation Mechanisms, Classification, and Influence on Catalytic Properties.

Spinel ferrites demonstrate extensive applications in different areas, like electrodes for electrochemical devices, gas sensors, catalysts, and magnetic adsorbents for environmentally important processes. However, defects in the real spinel structure can change the many physical and chemical properties of spinel ferrites. Although the number of defects in a crystal spinel lattice is small, their influence on the vast majority of physical properties could be really decisive. This review provides an overview of the structural characteristics of spinel compounds (e.g., CoFe2O4, NiFe2O4, ZnFe2O4, Fe3O4, γ-Fe2O3, Co3O4, Mn3O4, NiCo2O4, ZnCo2O4, Co2MnO4, etc.) and examines the influence of defects on their properties. Attention was paid to the classification (0D, 1D, 2D, and 3D defects), nomenclature, and the formation of point and surface defects in ferrites. An in-depth description of the defects responsible for the physicochemical properties and the methodologies employed for their determination are presented. DFT as the most common simulation approach is described in relation to modeling the point defects in spinel compounds. The significant influence of defect distribution on the magnetic interactions between cations, enhancing magnetic properties, is highlighted. The main defect-engineering strategies (direct synthesis and post-treatment) are described. An antistructural notation of active centers in spinel cobalt ferrite is presented. It is shown that the introduction of cations with different charges (e.g., Cu(I), Mn(II), Ce(III), or Ce(IV)) into the cobalt ferrite spinel matrix results in the formation of various point defects. The ability to predict the type of defects and their impact on material properties is the basis of defect engineering, which is currently an extremely promising direction in modern materials science.

Nature of Topological Phase Transition of Kitaev Quantum Spin Liquids.

We investigate the nature of the topological quantum phase transition between the gapless and gapped Kitaev quantum spin liquid phases away from the exactly solvable point. The transition is driven by anisotropy of the Kitaev couplings. At the critical point, the two Dirac points of the gapless Majorana modes merge, resulting in the formation of a semi-Dirac point with quadratic and linear band touching directions. We derive an effective Gross-Neveu-Yukawa-type field theory that describes the topological phase transition in the presence of additional magnetic interactions. We obtain the infrared scaling form of the propagator of the dynamical Ising order parameter field and perform a renormalization-group analysis. The universality of the transition is found to be different from that of symmetry-breaking phase transitions of semi-Dirac electrons. However, as in the electronic case, the Majorana fermions acquire an anomalous dimension, indicative of the breakdown of the fractionalized quasiparticle description.

Age and Sex Structure of the Population of the Potapovo and Sintashta Cultures in the Late Bronze Age Based on the Materials of Funerary Monuments from the Volga-Ural Region

The paper analyzes the gender and age structure of the population of the Potapovo and Sintashta cultures in the late Bronze Age based on anthropological materials from a cemetery in the Volga-Ural region. According to archaeological data, both of them belong to a single cultural block; nevertheless, issues of their correlation and primacy in the time of origin are still debatable. 336 markers of gender and age definition in the individuals were applied. Calculations of the main demographic indicators were carried out; histograms of the ratio of age and gender groups were constructed for each culture under consideration. Using the principal components method, an intergroup comparison was carried out on demographic indicators of 31 series in the south of Eastern Europe and Transcaucasia. The indicators of the Potapovo and Sintashta groups have high infant mortality. At the same time, more even ratios of sex and age classes were noted for the Sintashta group of the Trans-Urals. In contrast to Potapovo, a more favorable external and internal social situation for the Sintashta population is assumed. A comparison of demographic indicators against a broader geographical and chronological background demonstrates, firstly, the convergence of the Potapovo and Sintashta groups, the manifestation of similar trends among subsequent series of log culture in the same region, and, on the contrary, sharp differences with the data of the previous pastoral Yamno-Poltavka population. Thus, the demographic indicators of the Potapovo and Sintashta cultures can symbolize the transition to new ethno-cultural living conditions, to the beginning of the formation of stationary geographical points, to the gradual settling of collectives.

Enhancement of the anomalous Hall effect by distorting the Kagome lattice in an antiferromagnetic material

In topological magnetic materials, the topology of the electronic wave function is strongly coupled to the structure of the magnetic order. In general, ferromagnetic Weyl semimetals generate a strong anomalous Hall conductivity (AHC) due to a large Berry curvature that scales with their magnetization. In contrast, a comparatively small AHC is observed in noncollinear antiferromagnets. We investigated HoAgGe, an antiferromagnetic (AFM) Kagome spin-ice compound, which crystallizes in a hexagonal ZrNiAl-type structure in which Ho atoms are arranged in a distorted Kagome lattice, forming an intermetallic Kagome spin-ice state in the ab-plane. It exhibits a large topological Hall resistivity of ~1.6 µΩ-cm at 2.0 K in a field of ~3 T owing to the noncoplanar structure. Interestingly, a total AHC of 2,800 Ω-1 cm-1 is observed at ~45 K, i.e., 4 TN, which is quite unusual and goes beyond the normal expectation considering HoAgGe as an AFM Kagome spin-ice compound with a TN of ~11 K. We demonstrate further that the AHC below TN results from the nonvanishing Berry curvature generated by the formation of Weyl points under the influence of the external magnetic field, while the skew scattering led by Kagome spins dominates above the TN. These results offer a unique opportunity to study frustration in AFM Kagome lattice compounds.

Research on sustainable renewal of historic blocks based on urban catalyst theory

Currently, cities in China have entered the development stage of stock renewal. Urban renewal has become the focus of urban development, and optimization of stock space has become the main aspect of urban design. At the same time, applying the concept of micro-renewal of historic blocks in recent years has also put forward new requirements for the renewal mode of old blocks. This paper discusses the possibility of micro-renewal and transformation of historic Chinese blocks in the new era from the perspective of catalyst theory. Through streetscape recognition technology and crawling of Point of Information (POI) data, the existing problems of blocks and the potential vitality points of blocks are determined, which changes the traditional research that often lacks quantitative judgment and only uses qualitative judgment. Through the intervention of quantitative technology, the problems existing in the perspective rate of commercial streets and the business model of historical blocks were found. Analyzing from the perspective of space, function, and culture, and then, selecting catalyst elements, which promotes the transformation of the historic blocks from a top-down transformation pattern to a bottom-up transformation pattern.

Effect of Salt Content on Solubilization of Hydrophobic Polymer by Wormlike Micelles of Ionic Surfactant

The effect of concentration of inorganic salt KCl on solubilization of hydrophobic polymer poly(4-vinylpyridine) (P4VP) in aqueous solutions of ionic surfactant potassium oleate was experimentally investigated. As was shown by rheology, in the range of concentrations from 1 to 5 wt.% of salt the polymer-free solutions of surfactant mainly contain linear wormlike micelles (WLMs). The formation of branched WLMs was observed in the solutions containing 5-9 wt.% of KCl. In the presence of higher salt content the phase separation occurred, indicating the formation of a highly branched saturated network of WLMs. Enhanced screening of the charged groups of potassium oleate by oppositely charged ions of KCl caused elongation and branching of micelles that reflected in zero-shear viscosity of the solutions passing through the maximum. In the phase diagram, the saturation concentration with P4VP of both linear and branched WLMs decreased with increasing salt content. In the case of linear WLMs, this could be explained by the constant number of embedded polymer chains per 1 WLM, while simultaneously decreasing number of WLMs in the system. As for the branched WLMs, it was caused by shortening of the linear parts of micelles due to the formation of branching points. For this reason, almost no P4VP was dissolved in the solution containing the highly branched saturated network.

Comprehensive corrosion failure analysis of HAl77-2 alloy tubes serving in a low temperature multi-effect distillation plant: From feature analysis to corrosion mechanisms

Premature perforation and leakage of HAl77-2 alloy heat exchanger tubes occurs after 2.5 years of service in the largest low temperature multi-effect distillation (LT-MED) plant in China. The root reasons of perforation and leakage of tubes were investigated through macroscopic morphology, chemical composition, metallographic structure, seawater quality, flowing simulation and microstructure characterization. The results show that the HAl77-2 alloy tubes with perforation leakage meet the standard requirements. And the failure of the tubes was mainly attributed to the synergistic effect of serious pitting corrosion and stress cracking caused by the high fluid pressure and polluted seawater with Fe2+/Fe3+, sulfide and NH4+. Especially, the velocity and pressure spatial distribution of liquid film on the outside of horizontal tubes well verified the interesting observation that corrosion pits concentrating in one strip on the top of the tube. Moreover, corrosion mechanism was proposed that the loose corrosion products of Cu2S, FeS and Cu2(OH)3Cl lead to the formation of some defect points on the homogeneous protective Cu2O layer. For these defect points, the direct expose of the alloy matrix to corrosive substances such as Cl− and NH4+, significantly accelerates the dissolution of Cu in form of CuCl2− and Cu(NH3)2+ from the alloy. Finally, the tube occurs pitting corrosion and even perforates under the strong hydraulic erosion after long-terms of operation.

Mixing Performance of a Passive Micromixer Based on Split-to-Circulate (STC) Flow Characteristics.

We propose a novel passive micromixer leveraging STC (split-to-circulate) flow characteristics and analyze its mixing performance comprehensively. Three distinct designs incorporating submerged circular walls were explored to achieve STC flow characteristics, facilitating flow along a convex surface and flow impingement on a concave surface. Across a broad Reynolds number range (0.1 to 80), the present micromixer substantially enhances mixing, with a degree of mixing (DOM) consistently exceeding 0.84. Particularly, the mixing enhancement is prominent within the low and intermediate range of Reynolds numbers (0.1<Re<20). This enhancement stems from key flow characteristics of STC: the formation of saddle points around convex walls and flow impingement on concave walls. Compared to other passive micromixers, the DOM of the present micromixer stands out as notably high over a broad range of Reynolds numbers (0.1≤Re≤80).

The art of interdental contact point formation in Class II Black

The art of interdental contact point formation in Class II Black

Controlling lasing around exceptional points in coupled nanolasers

Coupled nanolasers are of growing interest for on-chip optical computation and data transmission, which requires an understanding of how lasers interact to form complex systems. The non-Hermitian interaction between two coupled resonators, when excited selectively, can lead to parity-time symmetry, the formation of exceptional points, and subsequently spectral control and increased sensitivity. These investigations have been limited to pump energies close to the lasing threshold, and large or narrow-line lasers. Here, by programmable optical excitation we study two coupled nanolasers significantly above threshold, where mode instability plays an important role. We map the mode evolution around two exceptional points, and observe lasing gaps due to reversed pump dependence which compare well with non-linear theory. Finally, the coupling can be exploited to control the lasing threshold and wavelength, and for frequency switching around the lasing gap. Controlled and integrated nanolasers constitutes a promising platform for future highly sensitive and programmable on-chip laser sources.

Tools for studying of facial identification and authentication

One of the most common and popular among biometric techniques is biometry of face. Currently, a large number of information systems have been created using these techniques. Thus, there is a problem of studying the methods of machine face recognition during the training of relevant specialists. The aim of the work is to develop a software tools for studying the mechanism of biometric face authentication. Face is static biometry methodic. For implementation in the developed tools the method of comparison on key points was chosen. The main stages of comparing faces are: finding a face in a photo, formation of key points, normalization, formation of segments, formation of relations, comparison of ratios. A high-level cross-platform programming language C++ with the use of additional libraries was chosen to develop the software of the tools. An open face database was used to work with the tools. The tools have a demonstration nature. During its use, you can explore and study all the components of the process of biometric identifi-cation and authentication of the user by face: demonstration of the process of finding of key points on the face, forming of distances between points, calculating of their ratios and their comparison; comparison of etalon and candidate photos during the procedure of identification and authentication and response. Examples of the main processing stages of the complex and the corresponding screen forms (windows) are given. The com-position of the tools and software are developed in the work, the main examples and stages of its work are given. It is shown that the tools can be used in the educational process, for example in laboratory or practical classes.

Comparative study on the performance of butt fusion-welding processes for nuclear safety class large-diameter thick-walled PE pipes

New technologies in polymer synthesis and pipe extrusion equipment have led to the commercialization of high-performance, large-diameter, thick-wall high density polyethylene (HDPE) pipes. They have been used in the field of seawater transport and cooling to replace metal pipes, due to their advantages of high corrosion resistance and extensibility. Connection of HDPE pipe is important as it determines the safety of the entire piping system. Butt fusion welding is commonly used for HDPE pipe connection but may cause the formation of weak points in the welded joints, interfering the reliability of the pipeline system in the application of nuclear power plants. At present, there is a lack of research on evaluating the performance of welded joint for large-diameter thick-wall HDPE pipes made by butt fusion-welding. The purpose of this study is to investigate the influence of three different butt fusion-welding processes, i.e., single low pressure (SLP), single high pressure (SHP) and dual low pressure (DLP), by evaluating the performance of their welded joints, including characterizing tensile strength, extensibility, crystallinity and hardness. In specific, a thick-wall HDPE pipe with OD of 812.8 mm and wall thickness of 74 mm which is certified for nuclear safety class was used for study. Representative specimen from the outer, middle and inner part across the wall of the main pipe body and welded joints were taken for testing. Different test methods and specimens were designed to assess the feasibility of evaluating the welding performance from different welding process. The results showed that the mechanical properties of different locations of the welded joints were different, and the tensile strength and fracture energy of the middle part of the joint were lower than that of the inner and outer parts, which could be caused by the difference in the crystallinity and thickness of the melting zone influenced by welding processes, as can be seen from the analysis of DSC test and morphology observation. Hardness testing was conducted on the section of the welded joints, and it revealed that the micromechanical properties of the welded joints in the region of the heat-affected zone were enhanced significantly, which may be due to the annealing effect caused by welding process. In summary, The DLP process resulted in the best extensibility of the welded joints among three processes, suggesting that the joining pressure from welding process plays an important role in affecting the extensibility of the welded joints.

Experimental study on flow characteristics of jet ventilation in crossflow in confined mine spaces

The increasing depth of mine excavation presents greater challenges in mine ventilation and in managing cooling energy consumption. Therefore, there is an urgent need for comprehensive research on jet ventilation influenced by low-speed crossflows. This study investigated the impact of flow velocity ratios (R) and jet exit diameters (d) on flow-field distribution and flow characteristics through velocity measurements and smoke flow visualization experiments. The results of the study revealed two distinct types of air lakes formed by jet ventilation in crossflow (JVIC), with one being wall-attached and the other suspended. Notably, a significant secondary flow phenomenon was observed in the near-field near the upper wall. Additionally, the deflection angle (θj) of JVIC decreases as R and d/D increase, leading to the formation and movement of a semi-confined point (SP) and a confined point (CP) in the -x direction. Moreover, the wall confinement effect diminishes the jet’s diffusion and deflection ability in the -z direction, leading to increased penetration in the x direction. Before the formation of the SP, the deflection section of the jet lengthens, followed by a rapid shortening upon its formation. Finally, the study further developed empirical equations for the jet axial trajectory and diffusion width.

A comparative experimental study on front and back laser cutting technology for mass separation of N-TOPCon crystal silicon solar cells

Generally, the Thermal Laser Separation (TLS) technology is used to pre-groove from the back of the cell, which is the first process of half-cell module preparation. However, this benchmark practice may result in forming new leakage points in the grooves at both ends of the cell. Hence, we investigate the mechanism behind the formation of leakage points after grooving and the impact on N-TOPCon's cell efficiency and module power. It is discovered that the diffusion of P element is the main reason for the increase in the proportion of leakage points. The front cutting is accordingly proposed to alleviate problem. A comprehensive experimental study on its feasibility has been conducted. It has been confirmed that the leakage current under the reverse bias voltage is smaller, the data convergence is better, and the breakdown performance is more stable for N-TOPCon. Furthermore, the module power is higher.

Relative age of the Devonian tetrapod Metaxygnathus, based on the associated fossil fish assemblage at Jemalong, New South Wales

A new genus, Jemalongia, is erected for a porolepiform shoulder girdle and associated scales from the Cloghnan Shale at Jemalong Weir, near Forbes in New South Wales, Australia. There is no evidence for the Late Devonian porolepiform Holoptychius that was previously associated with the tetrapod Metaxygnathus at this site. Scales and a partial articulated specimen of Holoptychius sp. from the Famennian Worange Point Formation at Eden on the New South Wales south coast are close to both Holoptychius sp. from East Greenland and Holoptychius nobilissimus from Scotland. However, evidently a species other than Holoptychius sp. is represented by scales in the Hunter Siltstone at Grenfell, central New South Wales. The Jemalong fossils share character states with other scales from Grenfell and Bogan Gate that show features resembling coelacanth scales; a scale attributed to the Devonian coelacanth Gavinia is shown here for comparison. An isolated tooth plate demonstrates a second lungfish taxon at Jemalong, in addition to the denticulate Soederberghia sp. There is insufficient evidence for referring the skull of Soederberghia to the type species Soederberghia groenlandica. Incomplete placoderm remains suggest that a new antiarch taxon may occur at Jemalong. This new evidence suggests that the age of the Jemalong assemblage should be revised downwards to Givetian–Frasnian or older, rather than Famennian as previously interpreted. Gavin C. Young [Gavin.Young@anu.edu.au; Gavinyoung51@gmail.com], Department of Materials Physics, Research School of Physics, Australian National University, Canberra, Australia; Australian Museum Research Institute, 1 Williams St, Sydney 2010, New South Wales, Australia.

Early Pliocene Ostracoda from the Jemmys Point Formation, Gippsland Basin, southeastern Australia: nearshore and offshore origins of biodiversity

Early Pliocene ostracod faunas of the Jemmys Point Formation, onshore Gippsland Basin, yield a rich and well-preserved marine ostracod fauna of mixed shallow marine and deep marine origins. The ostracod faunas evidence a marine continental shelf palaeoenvironment that, during the deposition of one stratigraphic interval, was influenced by a strong, persistent upwelling current. This upwelling current allowed the migration of deep-sea Ostracoda (Philoneptunus sp.) onto the continental shelf. The deeper marine aspect of this early Pliocene fauna, and of modern ostracod faunas from the Bass Strait region, evidence the adaptation of deep shelf taxonomic clades to shallow cool temperate shelf environments and highlights one unusual evolutionary mechanism that has contributed to modern Bass Strait shallow marine biodiversity. Four species are newly described: Neonesidea chapminuta sp. nov., Tasmanocypris salaputia sp. nov., Oculocytheropteron jemmyensis sp. nov., and Philoneptunus plutonis sp. nov. Abbey P. McDonald* [a.mcdonald@deakin.edu.au], School of Life and Environmental Sciences, Deakin University, Burwood, Victoria 3125, Australia; Elizabeth A. Weldon [l.weldon@deakin.edu.au], School of Life and Environmental Sciences and Deakin Marine Research and Innovation Centre, Deakin University, Burwood, Victoria 3125, Australia; Mark T. Warne [mark.warne@deakin.edu.au], School of Life and Environmental Sciences and Deakin Marine Research and Innovation Centre, Deakin University, Burwood, Victoria 3125, Australia, and Museums Victoria, GPO Box 666, Melbourne, Victoria 3001, Australia.

Paleoenvironmental variations during the Late Cambrian: Implications from Zn isotopes, I/(Ca+Mg) ratios, and other elemental proxies

The Upper Cambrian at the Martin Point section (∼110 m-thick) in western Newfoundland is a part of the Cow Head Group and partially spans the coeval Tuckers Cove and the Martin Point members of the Shallow Bay and Green Point formations, respectively. These units comprise alternating shale, minor conglomerate beds, and limestone rhythmites of a toe-of-slope apron. Earlier studies of the C-isotope profile, based on the lime mudstone interbeds, documented global negative δ13Ccarb shifts (from old to young: NL1, NL2, HERB) correlated with the lowermost Proconodontus posterocostatus, Proconodontus muelleri and base of Eoconodontus notchpeakensis conodont zones, respectively (post-Steptoean Positive Carbon Isotope Excursion NL1 and NL2 and Hellnmaria-Red Tops Boundary-HERB). Samples were extracted from the most preserved spots of micritic to near-micritic grain size (≤4 μm−10 μm). Fabric retention confirms petrographic preservation and insignificant correlations (R2 ≤ 0.1) of diagenetic proxies (e.g., Sr) with their environmental counterparts support the preservation of at least near-primary geochemical signatures. The paleoenvironmental proxies (TOC, Zn, P, Cu, Al/Ti, Mn, Fe, V, Mo) support dominant dysoxic conditions. The δ66Zn values (0.09–0.73 ‰ JMC Lyon) and (I/(Ca + Mg)) ratios (0.02–0.48 μmol/mol) vary consistently throughout the studied events. The minor decreases in δ66Zn values seem to denote inhibition of bioproductivity in a dysoxic water column, consistent with warm and humid climate during general transgressive settings and shoaling of organic-rich water into the shallow environment. The low I/(Ca + Mg) ratios (<0.5 μmol/mol) reinforce this interpretation, suggesting general dysoxic settings throughout the entire section.