Regressive Events Research Articles

The Campanian-Maastrichtian benthic foraminiferal assemblages at the Elles section (Tunisia): A perspective for paleoenvironmental, paleobathymetric and sea-level fluctuation reconstruction

The Late Cretaceous Period experienced prevailing hothouse conditions that were characterized by relatively elevated atmospheric pCO2 concentrations, high global mean sea level and mostly lacking ice sheets. These conditions were interrupted by an overall global decreasing trend in temperature during the Campanian-Maastrichtian interval (83.65 to 66.04 Ma). The Upper Cretaceous sedimentary successions in Tunisia (southwestern Tethyan Ocean) like at the Elles section are regarded as unique archives for investigating paleoenvironmental and paleoclimatic changes, as well as constrain oscillations of sea-level. Here, we perform high resolution quantitative analysis of the benthic foraminiferal assemblages in the Campanian-Maastrichtian interval at the Elles section in order to infer palaeoenvironmental and paleobathymetric changes in relative sea-level. The Campanian succession (Abiod Fm.) is inferred to be deposited at upper to middle bathyal (i.e., 540–675 m) and is characterized by prevailing well‑oxygenated conditions and low organic matter flux to the seafloor. The Campanian/Maastrichtian transition-coincides with the lowermost part of the El Haria Fm. deposited in outer neritic to upper bathyal settings under oligotrophic, well‑oxygenated and reduced productivity conditions. Shallower depositional setting (i.e., 436–515 m) is inferred for the Maastrichtian succession (El Haria Fm.) that is also characterized by a lowering in oxygen availability at the seafloor associated with an increase of organic matter. Eight main sea-level regressions (four in the Campanian, one at the Campanian-Maastrichtian transition and three in the Maastrichtian) have been identified and biostratigraphically constrained. These sea-level regression events are mostly accompanied by a negative excursion carbon isotope (δ13C) and their stratigraphical positions appear to be quite consistent with those previously recognized at the nearby El Kef section.

Mass mortality of Cornu aspersum in Italian snail farms: A histopathological survey

The production demand of edible snails in the Mediterranean area is very high and the attention to snail borne diseases is increasing. Following mass mortality events, we have analyzed 240 samples of Cornu aspersum collected from farms across Italy. Anatomopathological examination showed the presence of alterations of the gastro-intestinal apparatus and of the digestive gland, while histopathological examination revealed the presence of Rickettsia-like organisms (RLOs) in 70% (168/240) of cases and Giemsa positive amoebae in the remaining 30% (72/240) of cases. RLOs were localized mainly at the level of the DG, where regressive changes or nodular inflammation was observed. TEM examination of RLOs samples revealed the presence of many rod-shaped electron dense microorganisms. Amoebal infection occurred in the kidney, intestine, lung, the DG and were associated to regressive events or infiltrative/nodular and encapsulation like inflammation. To date it is still unclear if the pathogens detected could represent a risk for humans and animals, therefore further studies are needed to better elucidate this point.

Actinobacteria diversity associated with marine sediments and a wetland system, Agulhas-South Africa

BackgroundSouth Africa is known for its great biodiversity. The Agulhas Plain represents one such unique environment where low-gradient topography has resulted in extensive wetland formation. It is fed by two major river systems, bringing in brackish, alkaline water. It has been exposed to major marine transgression and regression events, and harbours great Fynbos diversity as well as a Mediterranean-type climate, thereby creating unique ecosystems. It is therefore surprising that little is known about the bacterial diversity associated with the Agulhas Plain and associated marine ecosystems.MethodsIn this study, we focused on the actinobacterial diversity (Phylum Actinomycetota) associated with an emerging peatland on the Agulhas Plain (SF; Areas 1–3) and a marine site (ANP; Ocean, Rocky, Dry) located 10 km away from SF. A combined metataxanomics and isolation approach was taken to evaluate the actinobacterial diversity of the sampling sites and to determine the effect of environmental physicochemical parameters on these populations. Various genome analyses were performed on an Sva0096 marine bin to gain insight into its ecological role.ResultsMetataxanomics showed that the two sites shared defined major taxa, including Blastococcus, Geodermatophilus, Microbacterium, Mycobacterium, Nocardioides, Streptomyces, and the Sva0996 marine group. Analysis of the biosynthetic potential of an Sva0996 marine bin134 (obtained from GenBank) provided insights into the potential ecological role of this group of bacteria in both the marine and terrestrial environments. Higher actinobacterial diversity (Shannon index > 5) was observed for Areas 2 and 3 (SF), as well as the ANP Dry samples. The actinobacterial population composition was found to be driven by salinity, pH, Mn, and Ca, with certain areas of SF exhibiting similar (and even higher) salinity (SF: 70–100 Ω vs. ANP: 100–160 Ω) and lower pH levels (SF: 6.3-8.0 vs. ANP: 8.6–8.9) to that of the marine environment.ConclusionThis snapshot study has provided some insights into the actinobacterial diversity of the two sites studied. Analysis of an Sva0096 marine bin134 provided further insights into the potential ability of the Sva0096 marine group to survive in a unique terrestrial environment that is periodically exposed to environmental pressures that mimic the marine environment.

Palynological data from the hauterivian Avilé Member, Pampa Tril section, Agrio Formation, Neuquén Basin, Argentina

The present contribution provides data to the palynological characterization of the non-marine deposits of the Avilé Member, Agrio Formation (Pampa Tril and San Eduardo sections), Neuquén Basin, Argentina. The Avilé Member, which represent a low-order regressive event, is one of the most important hydrocarbon reservoirs in the subsurface of the eastern part of the basin. A continental palynological association mainly represented by gymnosperms with Classopollis as a dominant taxon was recorded. The findings of Shambeipollenites proxireticulatus in the unit, extend the biostratigraphical range of the species to the Hauterivian and suggest the Neuquén Basin as an important dispersal place for the species within Gondwana landmass during the Early Cretaceous. A conifer-dominated forest was indicated by the pollen assemblage. The high percentages of Classopollis, the presence of pollen with Gnetidae affinity (Weltwischia/Ephedra) added to the evidence of fluvial-aeolian interaction given by the lithology, may be indicative of a deposition in a dryland setting. The recovered palynoflora was compared to published palynological data from different units underlying and overlying the Avilé Member, in order to evaluate the response of the vegetation in the central part of the basin, during the onset of non-marine accumulation relative to a sea level fall and the subsequent flooding again of the basin. An important variation in abundance between two groups of conifers (Cheirolepidiaceae versus Araucariaceae) is observed throughout the Agrio Formation members. Going up in the stratigraphic column there is an evident increase in abundance of Araucariaceae and a decrease in Classopollis and ferns spores.

Relative Sea-Level Fluctuations during Rhuddanian–Aeronian Transition and Its Implication for Shale Gas Sweet Spot Forming: A Case Study of Luzhou Area in the Southern Sichuan Basin, SW China

Most scholars believe that transgression events can contribute positively to organic matter enrichment and shale gas sweet spot development, while whether or not regression events are conducive to shale gas sweet spot development remains to be further discussed. Variations in organic carbon content (TOC), and major and trace elements at the Rhuddanian–Aeronian stage in the Luzhou area, the southern margin of Sichuan Basin, were analyzed in this paper. We discuss differences in paleoenvironment organic matter enrichment and shale sweet spot development during transgression and regression. A transgressive system tract (TST) occurred during the early Rhuddanian stage, while early highstand system tracts (Ehst-1 and Ehst-2) occurred during the late Rhuddanian stage and Aeronian stage, and a late highstand system tract (LHST) developed during the late Aeronian stage. A rise in sea level during the TST in the upper Yangtze resulted in an anoxic environment, where a continuous upwelling current brought about a large number of nutrients in the seawater, significantly increasing paleoproductivity. Strong tectonic subsidence, weak chemical weathering, and a rising sea level together led to a low terrigenous debris supply in the catchment area. Therefore, paleoproductivity and redox conditions were the primary controlling factors of organic matter enrichment at the TST stage, with a clastic supply of secondary importance. With the advance of the Guangxi orogeny, the organic matter enrichment at the EHST-1, EHST-2, and LHST stages was mainly controlled by redox conditions and debris supply. A comparison of the key physical parameters and geochemical indicators of shale reservoirs from these four system tracts suggests that two shale sweet spot types (type I and II) were developed during the Rhuddanian–Aeronian stage, occurring in the TST and EHST-2 stages. High TOC and high microcrystalline quartz content are key to developing type I sweet spots, while enhanced anoxic conditions in the bottom water caused by ephemeral, small-scale sea level rises are the main determinant of class II sweet spots in the later EHST stage.

Terminal Ediacaran–Late Ordovician evolution of the NE Laurentia palaeocontinent: rift–drift–onset of Taconic Orogeny, sea-level change and ‘Hawke Bay’ onlap (not offlap)

Abstract Rodinia break-up with late Ediacaran rifting defined a NE Laurentia triple junction (New York Promontory–Ottawa–Bonnechere aulacogen (OBA)–Quebec Reentrant). Rifting persisted to c. 510 Ma. The oldest passive-margin shelf units (Forestdale Marble and Moosalamoo Phyllite) underlie a sandstone (Cheshire) commonly regarded as the oldest passive unit. Late Dyeran–Middle Cambrian rifting led to the oldest OBa sedimentation and formed the Franklin Basin (NW Vermont). Cambrian–Darriwillian shelf–slope facies are linked eustatically – not Taconic Orogeny onset. Onlap and shelf carbonates are coeval with black slope mud; and lowstand shelf unconformities with green, oxic slope mud. Early–middle Dyeran eustatic change defined slope units: (1) Browns Pond Formation dysoxic–anoxic (d–a) interval with debrite cap (Holcombville Member, new); (2) Middle Granville Formation Oxic Interval (new); and (3) lower Hatch Hill Formation d–a interval. Our analysis leads to two controversial conclusions: (i) the existence of the Dashwoods and other micro-continental blocks due to hyperextension is not supported by cover sequences linking Laurentia to proposed Dashwoods areas (i.e. Green Mountains) and an arc origin of the type Dashwoods; and (ii) ‘Hawke Bay Event(s)’, widely interpreted as Cambrian global regressive event(s), is a local highstand systems tract facies with shelf sand bypass onto the Hatch Hill Formation slope in its NE Laurentia type region.

#2977 PROGRESSION AND REGRESSION OF CHRONIC KIDNEY DISEASE IN THE UNITED STATES USING ELECTRONIC MEDICAL RECORDS

Abstract Background and Aims Chronic kidney disease (CKD) is generally considered to be progressive and may lead to end-stage kidney disease (ESKD), or death. We aim to analyze a large US database and capture CKD progression, regression, ESKD and death over a 5-year follow-up, in a real-world setting. Method A retrospective cohort study was conducted using data from IBM® Explorys electronic medical records (>53 million patients) from 1 Jan 2010 to 31 Dec 2019. We created two main cohorts of patients with CKD: Cohort 1 and Cohort 2. Cohort 1 was based on diagnostic codes only (ICD 9/10, n = 810,987 unique patients), and Cohort 2 on KDIGO screening and staging criteria only (eGFR, UACR/UPCR values, n = 953,396). Within these cohorts, we created individual sub-cohorts for each CKD stage (1-5), though patient categorization was not mutually exclusive (one patient could contribute to multiple main and sub-cohorts). Patients in Cohort 1 were required to have an ICD code specific to a stage, and patients in Cohort 2 were required to have two consecutive laboratory test results within 3–18 months to determine KDIGO CKD stage. Index date was the date of diagnosis or second abnormal test with at least 12 months lookback period. Progression and regression were assessed for Cohort 1 using change in ICD codes and for Cohort 2, two test results (3-18 months apart) were required with a change in KDIGO eGFR stage and at least one of the values showing an increase or decrease by ≥25% in eGFR from baseline. We performed individual follow-up for progression and regression from each CKD stage to a progression or a regression event, death, loss to follow-up, or maximum 5 years, whichever came first. For ESKD, we followed up from each CKD stage to ESKD, death, loss to follow-up, or maximum 5 years. For death, we followed up from each CKD stage to death, loss to follow-up, or a maximum of 5 years. Results Most patients in Cohort 1 (ICD) and 2 (KDIGO) had stage 3 CKD at index. Mean age was 70y in Cohort 1 and 71y in Cohort 2, with 49% and 40% males, respectively. Both cohorts were predominantly Caucasian. The prevalence of cardiovascular diseases increased with CKD stage. The proportion of patients from Cohort 2 who had at least one CKD diagnosis increased from 34% in stage 1 to 86% and 83% in stage 4 and 5, respectively. CKD regression, ESKD and death increased progressively from stage 1–5 in both cohorts, except for stage 5 in Cohort 2. Progression in Cohort 1 decreased with stage and was variable in Cohort 2. The proportion of patients experiencing at least one event corresponding to CKD regression, progression, and ESKD was higher at all stages in Cohort 1 vs. Cohort 2, particularly ESKD which was markedly higher for stage 5 (91.4% vs. 13.6%). Proportion of death was similar in both cohorts and was the highest in stages 4–5. Conclusion Substantial differences in kidney outcomes were noted between CKD classifications derived from ICD codes vs. KDIGO criteria, except all-cause mortality which was comparable across both cohorts and increased notably with stage. Changes in kidney function, both progression, regression, and ESKD occurred more frequently in Cohort 1. Our analysis suggests ICD diagnosis and KDIGO criteria might not be used interchangeably in the context of utilizing real-world data sources.

The Paleoenvironment and Mechanisms of Organic Matter Enrichment of Shale in the Permian Taiyuan and Shanxi Formations in the Southern North China Basin

The organic-rich shale of the Permian Taiyuan Formation (TYF) and Shanxi Formation (SXF) in the Southern North China Basin (SNCB) is considered a potential shale gas source. The shale was formed in a marine-continental transitional sedimentary environment, which has rarely been studied, with the enrichment mechanisms of organic matter (OM) remaining unclear. This study investigated the controlling factors and enrichment mechanisms of OM by analyzing the total organic carbon (TOC) content, paleoclimate, paleoproductivity, sedimentation rate, redox, and paleosalinity. The TOC of the TYF ranged from 0.92 to 7.43 wt.%, with an average of 2.48 wt.%, which was higher than that of the SXF (TOC = 0.36–5.1 wt.%, average of 1.68 wt.%). These geochemical indices suggest that both the TYF and SXF were deposited in warm and humid paleoclimates, with relatively high biological productivity and sedimentation rates. During the deposition process, the TYF experienced frequent transgression and regression events, leading to an enhancement of water reducibility, a relatively high sedimentation rate, reduced OM oxidation, and rapid deposition of OM, which were conducive to the preservation of OM. Moreover, a high biological productivity increased respiratory oxygen consumption in the water column, which could lead to OM accumulation. However, the regression event experienced by the SXF reduced the paleoproductivity and sedimentation rate and increased water oxidation, leading to a decrease in OM. The main controlling factors for the enrichment of OM in the TYF and SXF were the sedimentation rate, paleoproductivity, and redox conditions, thus establishing the enrichment models for OM in the TYF and SXF. This study is conducive to understanding shale enrichment mechanisms and guiding shale gas exploration.

An integrated clinoform trajectory and sequence stratigraphic model for the Labrador margin, offshore eastern Canada

The passive margin offshore Labrador began forming during rifting in the Early Cretaceous, with seafloor spreading starting in the Maastrichtian and ending near the Eocene–Oligocene boundary. A foundational understanding of the associated stratigraphy of this margin has been developed through previous studies of the lithostratigraphy, biostratigraphy, and seismic stratigraphy, but the significance of clinoforms, stratal boundaries, and transgressive and regressive events has never been fully explored. In this study, we identify a series of clinoform successions from the Late Cretaceous through Pleistocene and apply a second-order sequence stratigraphic model to refine the geological framework for the margin. We focus on the Hopedale Basin where there is sufficient well and reflection seismic data, with substantial new seismic data collected over the last decade. Seismic interpretation is combined with paleoenvironmental and biostratigraphic data from the wells to map clinothem packages along the margin including: seven shoreline, five subaqueous delta, one shelf-edge, and three shelf-edge deltas, with illustration of these on seismic profiles and paleogeographic maps representing several time slices. Trajectory analysis of these clinothems permits the delineation of eight second-order sequences, with systems tracts and sequence stratigraphic surfaces identified. Broader implications of our results include a revised lithostratigraphic column for the Labrador margin. We further demonstrate regional trends during rifting and opening in term of controlling factors on clinoform development through comparison with adjacent and conjugate margins. Tectonism dominated as a controlling factor in the Cretaceous and dwindled near the end of the Paleocene. Eustasy and climate also influenced clinoform development in the Late Cretaceous, but became major factors during the Cenozoic, enhancing relative sea level fall and sediment supply, with similarities to other clinoform successions developed during Greenhouse and Icehouse conditions. Impacts to petroleum prospectivity in the region are also discussed, and our overall seismic and stratigraphic framework provide a basis for future study.

The sedimentological expression of transgression–regression cycles upon aeolian–marine margins

AbstractWhen compared to their temperate coastal counterparts, sediments deposited and preserved along arid aeolian to shallow‐marine margins remain relatively poorly understood, particularly at the scale of lithofacies units and architectural elements. These systems often record evidence for relative sea‐level change within sedimentary basins. This work focusses on the Entrada–Curtis–Summerville formations that crop out in central eastern Utah, USA, and provides a detailed analysis of the aeolian Moab Member of the Curtis Formation (informally known as the Moab Tongue) that was impacted by cycles of marine transgressions and regression in the late Jurassic. This study utilises photogrammetry, sedimentary logging and sequence‐stratigraphical analysis techniques. Results indicate that four short‐lived transgressive‐regressive cycles are preserved within the Moab Member, followed by a broad regressive event recorded at the transition between the Curtis and Summerville formations. These cycles relate to changes in the relative sea level of the Sundance Sea and the deflation and expansion of the neighbouring aeolian dune field. During periods of normal regression, marine sediments displayed evidence of tidal and wave action, whereas the continental domain was characterised by growth of the aeolian system. However, when regression occurred within optimal physiographic conditions such as a restricted, semi‐enclosed basin, and at sufficient magnitude to outpace erg expansion, this acted to shut‐down bedform development and preservation. A rapid restriction of aeolian sediment availability and the inability of the dune field to recover resulted in the formation of deflationary sandsheets, arid coastal plain strata and contemporaneous shallow‐marine deposits that are starved of wind‐sourced sediments. This study highlights how a rapidly developing high‐magnitude regression can lead to the overall retraction of the erg. Deciphering the evolution and sequence stratigraphical relationships of arid aeolian to shallow marine margins is important in both understanding environmental interactions and improving the characterisation of reservoir rocks deposited in these settings.

Risk of Long Covid in children infected with Omicron or pre-Omicron SARS-CoV-2 variants.

Risk of Long Covid in children infected with Omicron or pre-Omicron SARS-CoV-2 variants.

Facies analysis and depositional environment of a late Cambrian mixed carbonate-siliciclastic ramp from the Zard Kuh Mountain (Zagros Basin, south-western Iran)

Mixed carbonate-siliciclastic rocks were particularly widespread during the Furongian (late Cambrian), a critical time interval marked by biotic turnovers, extinction events and carbon cycle perturbations. In this context, the Zagros Basin (SW Iran) is a key area for the study of this time interval due to the well-exposed mixed carbonate-siliciclastic successions. Nevertheless, these are still poorly constrained from a sedimentological point of view. The current study aims to contribute to the palaeoenvironmental reconstruction of the Zagros Basin during the Furongian through high-resolution facies and microfacies analysis of the Tang-e-Ilbeyk section. The latter includes, in ascending order, the upper Mila C Member and Ilbeyk Formation. The facies and microfacies analysis recognized six facies associations, representing different settings of a mixed carbonate-siliciclastic ramp at the north-eastern Gondwanan margin. The vertical stacking pattern of these facies associations revealed five medium-scale Transgressive-Regressive cycles, superimposed by larger-scale sequences. In particular, during the latest Miaolingian (formerly late middle Cambrian) to early Furongian, a climate change from arid to humid conditions caused a major regressive event with the progradation of clastic shorelines and the following pollution and drowning of the Mila C Member's carbonate factory. The latter was replaced by a storm-dominated siliciclastic shelf (Ilbeyk Formation) that, throughout middle/late Furongian, experienced a large-scale transgressive event, culminating with a maximum flooding interval. A significant forced regression occurred in the latest Furongian when shallow water conditions were re-established (uppermost Ilbeyk Formation). The palaeoenvironmental reconstruction of this study allowed correlation with other coeval depositional events at regional (Arabian plate) and global (Laurentia and Baltica) scales, contributing to new constraints for the lower Palaeozoic evolution of north-eastern Gondwana.

Sedimentary response and restoration of paleoshoreline of Taiyuan-Shanxi Formations in North China basin

The Permian Taiyuan-Shanxi Formations in the North China Basin are a series of terrestrial-marine strata whose depositional evolution exhibits unique particularities. Current studies involving the paleoenvironment of the Taiyuan and Shanxi Formations are mainly supported by sedimentary facies or geochemical analysis, yet studies on the sedimentary and geochemical responses of the paleoshoreline remain inadequate, which leads to the inconsistency of the concluded paleoshoreline distribution. Based on outcrop data, well data and major and trace element analysis, sedimentary and geochemical features of the paleoshoreline in both formations are identified. Combining sedimentary facies and geochemical analysis, this study aims to restore the distribution of the paleoshoreline in the Taiyuan and Shanxi Formations as well as its migrations.The outcrop and well data show that the paleoshoreline of the Taiyuan and Shanxi Formations features 3 types of sedimentary responses: (1) distributary channel deposits of the delta plain + argillaceous deposits of the delta front; (2) peat mire of the delta plain + argillaceous deposits of the delta front; and (3) distributary channel deposits of the delta plain + tidal flat-lagoon deposits. Based on major and trace element results, Sr/Ba, m = 100 × (MgO/Al2O3), Mn/Fe, f = (Rb/K)/(Zr/Al), CIA, Sr/Cu, V/(V + Ni), and V/Cr are selected as proxies for paleosalinity, paleowater depth, paleoclimate and paleo-redox conditions. The results show that transitional-brackish water was dominant during the transgression period of the Taiyuan Formation with mild changes in paleowater depth, while fresh water primarily covered the North China Basin during regression during the Shanxi Period, which was a time when paleo-water depth exhibited evident fluctuation in the northern region. Generally, the paleoclimate during the Taiyuan-Shanxi Period was warm and moist to hot and humid, and the paleo-redox conditions were anoxic to reductive.Under the influence of transgression during the Taiyuan Period, the boundary of the freshwater zone closely matches the maximum range of marine deposition, indicating a generally steady transgression background; additionally, the paleoshoreline was distributed in the vicinity of Yulin - Shijiazhuang - Baoding. During the regression event of the Shanxi Period, the paleoshoreline migrated southeast to the south of ZK03-2 and southeast of Yu88, extending southward along Sanmenxia - Luoyang - Zhengzhou - Yuzhou, and the freshwater zone extended southward and covered a considerable range of marine deposition, indicating a strong flux of terrestrial freshwater with periodic transgression. The analysis and conclusions in this paper would hopefully provide insights and a reference for the paleoenvironmental evolution and shoreline changes in the Taiyuan - Shanxi Formations of the North China Basin.

Paleoenvironmental and diagenetic evolution of the Aptian Pre-Salt succession in Namibe Basin (Onshore Angola)

The Aptian Pre-Salt sedimentary succession cropping out in Cangulo palaeovalley onshore Namibe Basin (Angola) was studied by a combination of field and analytical techniques to constrain the sedimentary and diagenetic evolution of the uppermost sag sequence of the South Atlantic passive margin. Field observations allows definition of four transgressive-regressive cycles characterised by fluvial to tidal-influenced mixed clastic-carbonate and carbonate-dominated deposits, that locally show evidence of evaporite dissolution; highlighting that evaporite deposition started earlier than deposition of the regional South Atlantic Loeme-Bambata evaporite formations. Two separate pre-salt carbonate units have been differentiated within the Cangulo Fm; i) a lower transitional to marginal marine, and ii) a younger upper non-marine freshwater travertine system, that is documented for the first time in the west African margin. Transgressive-regressive cycles control the early diagenesis of the tidal carbonates that include dolomitization due to mixing fluids during transgressions, and karstification due to evaporite dissolution by meteoric water circulation during regressive events. Clastic supply appears to have been completely shut down during carbonate deposition, suggesting major climatic change associated with carbonate deposition. During the lowstand between the two carbonate units, fluid flow through Cangulo palaeovalley was re-established resulting in extensive karstification and formation of a large-scale erosional unconformity that is interpreted to be time equivalent to an intra Chela-Cuvo Fm. event. The top of the studied succession corresponds to the transgressive deposits of the Bambata evaporites that are not preserved in the Cangulo palaeovalley due to its erosion but are regionally developed. The results of this study can be directly linked to along strike age equivalent Pre-Salt successions cropping out in the Namibe, Benguela and Kwanza basins, and directly offshore Angola and Brazil using well and seismic data. These new data shed important new light and constraints on the depositional and diagenetic evolution of the complex Pre-Salt reservoir systems of the South Atlantic, and the depositional and bathymetric setting at the time of onset of the main south Atlantic evaporite deposition.

Sequence stratigraphy of the Paleocene succession in the Kharga Oasis, Western Desert, Egypt: insights from microplankton biostratigraphy and benthic foraminifer paleoenvironments

The present work provides a comprehensive stratigraphic consideration for the Paleocene (Danian–early Thanetian) succession in the Gebel El-Teir section, Kharga Oasis, Western Desert. The study incorporates calcareous nannofossils, foraminifers (planktic and benthic), and microfacies analyses to deduce fluctuations in the relative sea level and construct a sequence stratigraphic framework. In terms of the microplankton biostratigraphy, five planktic foraminifer (P2, P3a, P4a, P4b, and P4c) and four calcareous nannofossil (NP4–NP6 and NP8) zones have been recognized. Moreover, three biostratigraphic hiatuses were recognized based on the integration between the calcareous nannofossil and planktic foraminifer bioevents. These hiatuses aided in subdividing the studied interval into four 3rd order depositional sequences (D-DS1, S-DS2, S/Th-DS3, and Th-DS4). The paleo-water-depth variations deduced from the foraminiferal and sedimentological proxies facilitate the establishment of a relative sea-level curve and, subsequently, the systems tracts of each depositional sequence were readily recognized. The shallowest water conditions (middle neritic setting) occurred during the deposition of the Danian interval. However, a much deeper paleoenvironment (deep outer neritic-upper bathyal settings) marks the Selandian/Thanetian (S/Th) transition interval. The proposed sequence stratigraphic model and the presence of some extended hiatuses attribute the primary cause for accommodation destruction/creation to the regional tectonic uplift/subsidence. However, once the basin had been formed, the relative sea level within the individual depositional sequence behaved in a manner consistent with the contemporaneous eustatic 3rd-order transgression and regression events.

Characteristics of Calcium Isotopes at Different Water Depths and Their Palaeoenvironmental Significance for Carbonate Rocks of the Permian-Triassic Boundary in Chibi, Southern China

Calcium isotopes of carbonate rocks can trace calcium cycles and record changes in the marine environment. As published calcium isotope profiles of carbonate rocks at the Permian-Triassic boundary are rare, comparative studies on deep-water profiles were lacking for the major extinction event that occurred during this time. We present sections of different water depths in the Chibi area of southern China that we have selected for a comparative study. We analyzed carbon isotopes, calcium isotopes, as well as major and trace elements of carbonates from two sections (Chibi North and Chibi West) to obtain information on the volcanic activity, ocean acidification, as well as sea level rise and fall in the Chibi area during the mass extinction period. All carbon and calcium isotopes of carbonates from both sections are all negative after the mass extinction boundary. Carbonates from the Chibi North section have higher δ44/40Ca values and lower Sr/Ca ratios than the rocks from the Chibi West section. We propose that the negative bias of the calcium isotopes in the two sections result from diagenesis. Diagenesis transforms primary aragonite into calcite, showing the characteristics of high δ44/40Ca value and low Sr/Ca. By comparing our data with three published profiles of shallow-water carbonate rock, we recognize that calcium isotopes record gradients at different water depths. In the slope environment, the enhancement of pore fluid action near the coast caused an increase of the fluid buffer alteration, and we propose that a regression event occurred in the Chibi region during the Late Permian.

Air Pollution and Maximum Temperature Are Associated with Neurodevelopmental Regressive Events in Autism Spectrum Disorder

Neurodevelopmental regression (NDR) is an enigmatic event associated with autism spectrum disorder (ASD) during which a child loses previously acquired skills and develops ASD symptoms. In some, a trigger which precedes the NDR event, such as a fever, can be identified, but in many cases no trigger is obvious. We hypothesize that air pollution (PM2.5) may trigger NDR, especially in those children without an identified trigger. Average daily PM2.5, ozone, precipitation and maximum temperature (Tmax) were derived from Environmental Protection Agency models and National Oceanic and Atmospheric Administration monitors based on zip-code information from 83 ASD participants during the six-weeks following the onset month of an NDR event and a reference period defined as one year before and one year after the event. Seasonally adjusted logistic regression (LR) and linear mixed models (LMM) compared cases (with a history of NDR) and matched controls (without a history of NDR). LR models found that the risk of NDR was related to higher PM2.5 during 3 to 6 weeks of the NDR event period, particularly in those without a trigger. Overall, both models converged on NDR being related to a higher PM2.5 and lower Tmax both during the NDR event period as well as the reference period, particularly in those without a known trigger. This temporal pattern suggests that environmental triggers, particularly PM2.5, could be related to NDR, especially in those without an identifiable trigger. Further studies to determine the underlying biological mechanism of this observation could help better understand NDR and provide opportunities to prevent NDR.

Combining Optical Coherence Tomography and Optical Coherence Tomography Angiography Longitudinal Data for the Detection of Visual Field Progression in Glaucoma

To use longitudinal optical coherence tomography (OCT) and OCT angiography (OCTA) data to detect glaucomatous visual field (VF) progression with a supervised machine learning approach. Prospective cohort study. One hundred ten eyes of patients with suspected glaucoma (33.6%) and patients with glaucoma (66.4%) with a minimum of 5 24-2 VF tests and 3 optic nerve head and macula images over an average follow-up duration of 4.1 years were included. VF progression was defined using a composite measure including either a "likely progression event" on Guided Progression Analysis, a statistically significant negative slope of VF mean deviation or VF index, or a positive pointwise linear regression event. Feature-based gradient boosting classifiers were developed using different subsets of baseline and longitudinal OCT and OCTA summary parameters. The area under the receiver operating characteristic curve (AUROC) was used to compare the classification performance of different models. VF progression was detected in 28 eyes (25.5%). The model with combined baseline and longitudinal OCT and OCTA parameters at the global and hemifield levels had the best classification accuracy to detect VF progression (AUROC=0.89). Models including combined OCT and OCTA parameters had higher classification accuracy compared with those with individual subsets of OCT or OCTA features alone. Including hemifield measurements significantly improved the models' classification accuracy compared with using global measurements alone. Including longitudinal rates of change of OCT and OCTA parameters (AUROCs=0.80-0.89) considerably increased the classification accuracy of the models with baseline measurements alone (AUROCs=0.60-0.63). Longitudinal OCTA measurements complement OCT-derived structural metrics for the evaluation of functional VF loss in patients with glaucoma.

A methodology for equipment condition simulation and maintenance threshold optimization oriented to the influence of multiple events

The core of condition-based maintenance is the accurate evaluation of equipment state. For various equipment, performance degradation or regression caused by factors, such as unexpected shock, failure, and work stress withdrawal, is typical. Accordingly, the law on incorporating impulse, failure, maintenance, and regression events based on natural condition evolution is analyzed. Moreover, a mathematical model and simulation algorithm of equipment condition evolution are devised. Then, considering safety, availability, and economy, the optimal maintenance threshold is determined based on the condition evolution process, providing new technical support to the field of maintenance decision-making. Finally, the effectiveness of the proposed model and algorithm is proved. The improved conformance of the stochastic process to actual situations considering the influence of multiple events is thus demonstrated. Further, a new concept for equipment maintenance management is presented.

Biostratigraphy and paleoenvironment correlation based on benthic foraminifera from the cenozoic Marajó and Pirabas formations, Eastern Amazon Coast, Brazil

The Oligocene-Miocene foraminifera biostratigraphy correlation has been applied successfully as a geological tool for establishing the paleoenvironmental conditions during the deposition of siliciclastic and carbonate strata in the Eastern Amazon coastal basins. In this region, previously interpreted tectonic compartments represented by the Marajó Basin and Bragantina Platform were the main sites of siliciclastic and carbonate sedimentation influenced by Late Paleogene-Neogene transgressive–regressive events. In the subsident Marajó basin, a siliciclastic estuary was developed, supplied by the Cratonic Amazon River. The transcontinental river did not influence the Bragantina region to the East, allowing the implantation of a shallow carbonate platform. These Neogene segments require further sedimentological, stratigraphic, and paleontological studies to define these limits. The use of foraminifera content has been considered an important tool to assist in this differentiation, providing a paleoenvironmental and paleoecological reconstruction model. This work used qualitative and quantitative analyses integrating several diversity indices, complementing the R-mode cluster and the correlation of planktonic and benthic (P/B) ratios. The similarity in faunal diversity indicated that these siliciclastic and carbonate units represented by the Marajó and Pirabas formations are chronocorrelated. Marajó Formation is interpreted as a restricted, suboxic, marginal marine environment (lagoons/mangroves) with variable salinity and abundance of the species as Cribroelphidium williamsoni, Ammonia tepida, and A. beccari. In contrast, the Pirabas Formation was deposited in a brackish, oxic, and carbonate platform characterized by Cibicidoides subhaidingerii, Cibicides pachyderma A. beccarii, and Cassidulina laevigata species. These foraminifera assemblages confirm the previous stratigraphic and paleoenvironmental interpretations providing new insights into understanding the Late Paleogene-Neogene evolution of the Eastern Amazonia Coast.