The relationship between dinosaurs and other reptiles is well established, but the sequence of acquisition of dinosaurian features has been obscured by the scarcity of fossils with transitional ...morphologies. The closest extinct relatives of dinosaurs either have highly derived morphologies or are known from poorly preserved or incomplete material. Here we describe one of the stratigraphically lowest and phylogenetically earliest members of the avian stem lineage (Avemetatarsalia), Teleocrater rhadinus gen. et sp. nov., from the Middle Triassic epoch. The anatomy of T. rhadinus provides key information that unites several enigmatic taxa from across Pangaea into a previously unrecognized clade, Aphanosauria. This clade is the sister taxon of Ornithodira (pterosaurs and birds) and shortens the ghost lineage inferred at the base of Avemetatarsalia. We demonstrate that several anatomical features long thought to characterize Dinosauria and dinosauriforms evolved much earlier, soon after the bird-crocodylian split, and that the earliest avemetatarsalians retained the crocodylian-like ankle morphology and hindlimb proportions of stem archosaurs and early pseudosuchians. Early avemetatarsalians were substantially more species-rich, widely geographically distributed and morphologically diverse than previously recognized. Moreover, several early dinosauromorphs that were previously used as models to understand dinosaur origins may represent specialized forms rather than the ancestral avemetatarsalian morphology.
The early evolutionary history of Ornithodira (avian-line archosaurs) has hitherto been documented by incomplete (Lagerpeton) or unusually specialized forms (pterosaurs and Silesaurus). Recently, a ...variety of Silesaurus-like taxa have been reported from the Triassic period of both Gondwana and Laurasia, but their relationships to each other and to dinosaurs remain a subject of debate. Here we report on a new avian-line archosaur from the early Middle Triassic (Anisian) of Tanzania. Phylogenetic analysis places Asilisaurus kongwe gen. et sp. nov. as an avian-line archosaur and a member of the Silesauridae, which is here considered the sister taxon to Dinosauria. Silesaurids were diverse and had a wide distribution by the Late Triassic, with a novel ornithodiran bauplan including leaf-shaped teeth, a beak-like lower jaw, long, gracile limbs, and a quadrupedal stance. Our analysis suggests that the dentition and diet of silesaurids, ornithischians and sauropodomorphs evolved independently from a plesiomorphic carnivorous form. As the oldest avian-line archosaur, Asilisaurus demonstrates the antiquity of both Ornithodira and the dinosaurian lineage. The initial diversification of Archosauria, previously documented by crocodilian-line archosaurs in the Anisian, can now be shown to include a contemporaneous avian-line radiation. The unparalleled taxonomic diversity of the Manda archosaur assemblage indicates that archosaur diversification was well underway by the Middle Triassic or earlier.
The southern part of the Karoo Basin of South Africa contains a near complete stratigraphic record of the Permo-Triassic boundary (PTB). Isotope- and magneto-stratigraphy confirm that these ...predominantly fluvial strata are approximately the same age as zircon-dated marine PTB sections (252Mya). By August 2013, our team had found 579 in situ vertebrate fossils, mostly of the clade Therapsida, in PTB exposures at three widely separated locations in the southern Karoo Basin. Biostratigraphic ranges of the various taxa found in each of the sections reveal three separate phases of die-off within the same roughly 75 metre-thick stratigraphic interval displaying the same sequence of sedimentary facies interpreted as indicative of climatic drying, increased seasonality and the onset of an unpredictable monsoon-type rainfall regime. The three phases of an inferred ecologically-stepped mass extinction are: Phase 1 (45m–30m below PTB datum) brought on by lowered watertables, which led to loss of shallow rooting groundcover in the more elevated proximal floodplain areas and the disappearance of the smaller groundcover-grazing herbivorous dicynodonts and their attendant small carnivores. Phase 2 (20–0m below PTB datum), is the main extinction that occurs in massive maroon/grey mudrock culminating in an event bed of laminated reddish-brown siltstone/mudstone couplets. This facies reflects progressively unreliable rainfall leading to vegetation loss in proximal and distal floodplain areas. The larger tree-browsing herbivores and their attendant carnivores are confined to watercourses before finally disappearing. Phase 3 (25–30m above PTB datum) occurs in massive maroon siltstone facies with evidence of climatic aridity including the accumulation of mummified carcasses buried by windblown dust. All of the surviving Permian taxa disappear within 30m of the PTB.
Temporal resolution based on accretion rates and pedogenic maturity of each stratigraphic section reveals that Phase 1 and Phase 2 die-offs lasted 21000 and 33000years separated by a short period of 7000years where no disappearances are recorded and this was followed by 50000years of stasis for the final extinction phase, lasting only 8000years, that removed all the Permian survivor taxa,. We propose that the recorded disappearances are real (rather than preferential preservation failure) and that they represent drought-induced die-offs moving progressively up the food chain as the terrestrial ecosystem collapsed; the latter mostly likely caused by volcanogenic greenhouse gas emissions and rapid global warming.
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•Karoo fossils preserve a terrestrial record of the End-Permian mass extinction.•Extinction and recovery phases defined by 32 vertebrate biostratigraphic ranges.•Fluvial facies reflect rapid climatic drying co-incident with the extinction event.•Three phases of drought-induced die-off occurred over approximately 120000years.•Small herbivores died-off first followed large browsers finally all the surviving taxa.
This article reviews progress in understanding the fluid dynamics and moist thermodynamics of tropical cyclone vortices. The focus is on the dynamics and moist thermodynamics of vortex ...intensification and structure. We discuss previous ideas on many facets of the subject and articulate also some open questions. The advances reviewed herein provide new insight and tools for interpreting complex vortex-convective phenomenology in simulated and observed tropical cyclones.
Newborns are at greatest risk of dying at and shortly after the time of birth. Newborn mortality remains an urgent concern and is an important indicator of child health, development and well-being. ...Studies examining the effectiveness of antenatal care on maternal and newborn health outcomes have provided conflicting results. The aim of this review and meta-analysis was to determine the pooled effect of antenatal care on neonatal mortality in sub-Saharan Africa.
We searched PubMed, Medline, EMBASE, CINAHL and Google Scholar from September to November 2016 and then updated our search on April 13, 2019. Two independent reviewers extracted data from eligible studies. The quality of each included study was assessed using the Risk of Bias Assessment tool for Non-Randomized Studies (RoBANS). The results were reported based on risk ratio (RR) with 95% confidence intervals (CI) using a random-effects model.
Eight hundred and ninety eight studies were initially identified. During screening, 23 studies were found to be relevant for data extraction. Of these, only twelve studies fulfilled the inclusion criteria and were included in the analysis. In five of the twelve studies included in the analysis, antenatal care service utilization had a significant association with neonatal mortality. The pooled risk ratio by the random-effects model was 0.61 (95% CI: 0.43, 0.86) for neonates born to women who received at least one antenatal care visit by a skilled provider as compared to neonates born to women who did not receive antenatal care.
This review indicates that utilization of at least one antenatal care visit by a skilled provider during pregnancy reduces the risk of neonatal mortality by 39% in sub-Saharan African countries. Thus, in order to accelerate progress towards the reduction of newborn deaths, all pregnant women should receive antenatal care during pregnancy.
In the context of high maternal morbidity and mortality in Sub-Saharan Africa, less than 80% of pregnant women receive antenatal care services. According to a 2016 national report, only 62% of ...pregnant women in Ethiopia made at least one antenatal care visit. The aim of this review was to systematically and quantitatively summarize the factors affecting utilization of antenatal care in Ethiopia.
We searched PubMed, Medline, EMBASE, CINAHL, Google Scholar and Maternity and Infant Care database for studies that had been conducted in Ethiopia between 2002 and 2016. We summarized the studies on the use of antenatal care services quantitatively and qualitatively. A random-effects model was conducted to obtain the pooled estimates.
A total of fifteen observational studies were included in this review. The pooled prevalence of utilization of antenatal care services in Ethiopia was 63.77% (95CI 53.84-75.54). The pooled odds ratio showed that a significant positive association was found between utilization of antenatal care and urban residence (OR = 1.92, 95%CI = 1.35-2.72), women's education (OR = 1.90, 95%CI = 1.52-2.37), husband's education (OR = 1.49, 95%CI = 1.32-1.69) and planned pregnancy (OR = 2.08, 95%CI = 1.45-2.98). Based on narrative synthesis exposure to mass media, family income and accessibility of the service were strongly associated with utilization of antenatal care.
The findings of this review found several modifiable factors such as empowering women through education and increasing their decision-making power, promoting family planning to prevent unplanned pregnancy, increasing awareness of women through mass media and making services more accessible would likely to increase utilization of antenatal care. Further research is needed on accessibility and availability of the service at the individual and community level to assess the predictors of antenatal care service utilization.
The latest Permian mass extinction (LPME) was triggered by magmatism of the Siberian Traps Large Igneous Province (STLIP), which left an extensive record of sedimentary Hg anomalies at Northern ...Hemisphere and tropical sites. Here, we present Hg records from terrestrial sites in southern Pangea, nearly antipodal to contemporaneous STLIP activity, providing insights into the global distribution of volcanogenic Hg during this event and its environmental processing. These profiles (two from Karoo Basin, South Africa; two from Sydney Basin, Australia) exhibit significant Hg enrichments within the uppermost Permian extinction interval as well as positive Δ
Hg excursions (to ~0.3‰), providing evidence of long-distance atmospheric transfer of volcanogenic Hg. These results demonstrate the far-reaching effects of the Siberian Traps as well as refine stratigraphic placement of the LPME interval in the Karoo Basin at a temporal resolution of ~10
years based on global isochronism of volcanogenic Hg anomalies.
Earth's largest biotic crisis occurred during the Permo-Triassic Transition (PTT). On land, this event witnessed a turnover from synapsid- to archosauromorph-dominated assemblages and a restructuring ...of terrestrial ecosystems. However, understanding extinction patterns has been limited by a lack of high-precision fossil occurrence data to resolve events on submillion-year timescales. We analyzed a unique database of 588 fossil tetrapod specimens from South Africa's Karoo Basin, spanning ∼4 My, and 13 stratigraphic bin intervals averaging 300,000 y each. Using sample-standardized methods, we characterized faunal assemblage dynamics during the PTT. High regional extinction rates occurred through a protracted interval of ∼1 Ma, initially co-occurring with low origination rates. This resulted in declining diversity up to the acme of extinction near the
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Assemblage Zone boundary. Regional origination rates increased abruptly above this boundary, co-occurring with high extinction rates to drive rapid turnover and an assemblage of short-lived species symptomatic of ecosystem instability. The "disaster taxon"
shows a long-term trend of increasing abundance initiated in the latest Permian.
comprised 54% of all specimens by the onset of mass extinction and 70% in the extinction aftermath. This early
abundance suggests its expansion was facilitated by environmental changes rather than by ecological opportunity following the extinctions of other species as commonly assumed for disaster taxa. Our findings conservatively place the Karoo extinction interval closer in time, but not coeval with, the more rapid marine event and reveal key differences between the PTT extinctions on land and in the oceans.
Each year, nearly 4 million pregnant patients in the United States receive prenatal care—a crucial preventive service that improves pregnancy outcomes for mothers and their children. National ...guidelines currently recommend 12–14 in-person prenatal visits, a schedule that has remained unchanged since 1930. When scrutinizing the standard prenatal visit schedule, it becomes clear that prenatal care is overdue for a redesign. We have strong evidence of the benefits of prenatal services, such as screening for gestational diabetes and maternal vaccination. However, how to deliver these services is not clear. Studies of prenatal services consistently demonstrate that such care can be delivered in fewer than 14 visits and that patients do not need to visit clinics in person to receive all maternity services. Telemedicine has emerged as a promising care delivery option for patients seeking greater flexibility, and early trials leveraging virtual care and remote monitoring have shown positive maternal and fetal outcomes with high patient satisfaction.
Our institution has worked for the past year on a new prenatal care pathway. Our initial work assessed the literature, elicited patient perspectives, and captured the insights of experts in patient-centered care delivery. There are 2 key principles that guide prenatal care redesign: (1) design care delivery around essential services, using in-person care for services that cannot be delivered remotely and offering video visits for other essential services, and (2) creation of flexible services for anticipatory guidance and psychosocial support that allow patients to tailor support to meet their needs through opt-in programs. The rise of coronavirus disease 2019 prompted us to extend this early work and rapidly implement a redesigned prenatal care pathway. In this study, we outline our experience in transitioning to a new prenatal care model with 4 in-person visits, 1 ultrasound visit, and 4 virtual visits (the 4-1-4 prenatal plan). We then explore how insights from this implementation can inform patient-centered prenatal care redesign during and beyond the coronavirus disease 2019 pandemic.
The dual-use of games in both military and entertainment applications has a long history. This has taken the form of sand tables, miniatures, board games, and computer games. The current tension ...between entertainment and military applications over games is just the return of similar concerns that have surrounded gaming tools and technologies in previous generations. Dynamic representations of the physical world are interesting and useful tools in a number of fields, to include the military, city planning, architecture, education, and entertainment. Modern computer games contain technologies and tools that allow many different communities to accomplish similar goals.
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