31 research outputs found

    Probabilistic Programming with Densities in SlicStan: Efficient, Flexible, and Deterministic

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    Stan is a probabilistic programming language that has been increasingly used for real-world scalable projects. However, to make practical inference possible, the language sacrifices some of its usability by adopting a block syntax, which lacks compositionality and flexible user-defined functions. Moreover, the semantics of the language has been mainly given in terms of intuition about implementation, and has not been formalised. This paper provides a formal treatment of the Stan language, and introduces the probabilistic programming language SlicStan --- a compositional, self-optimising version of Stan. Our main contributions are: (1) the formalisation of a core subset of Stan through an operational density-based semantics; (2) the design and semantics of the Stan-like language SlicStan, which facilities better code reuse and abstraction through its compositional syntax, more flexible functions, and information-flow type system; and (3) a formal, semantic-preserving procedure for translating SlicStan to Stan

    THE CASE FOR THE GLOBAL STRATOTYPE SECTION AND POINT(GSSP) FOR THE BASE OF THE NORIAN STAGE

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    The Norian Stage is the longest stage in the Phanerozoic, and some members of the boundary working group have been evaluating suitable Carnian-Norian boundary sections for roughly two decades. This has identified two possible candidate boundary sections, at Black Bear Ridge (British Columbia, Canada) and Pizzo Mondello (Sicily, Italy). After a formal voting procedure within the working group, ending on the 26th July, 2021, the Pizzo Mondello section was selected as the global stratotype section and point for the base of the Norian. We evaluated the global correlation potential of the two proposed primary markers, the conodont Metapolygnathus parvus and the ‘flat-clam’ Halobia austriaca. Secondary markers were also evaluated around these boundary datums for correlation potential, and the veracity of the proposed sections for GSSP status. Data and arguments for the proposed sections and datums are presented here. Through a two-stage process of option elimination in voting, conforming with ICS guidelines, the working group decided by 60% majority to propose that the first occurrence datum of Halobia austriaca in the Pizzo Mondello section at the base of bed FNP135A should become the ‘golden spike’ for the base of the Norian. A secondary biotic marker for this boundary is the first occurrence of Primatella (Carnepigondolella) gulloae, in sample NA43, ca. 0 m below FNP135A, and the FA of Dimorphites noricus (sample NA42.1) ca. 3.5 m above bed FNP135 (indicating the first subzone of the Jandianus Zone). The best physical secondary marker is the magnetozone PM5n with the proposed boundary ca.40% through the thickness of PM5n. Strengths of the chosen datum are: 1) it also maintains historical priority for ammonoid zonations, which had placed the base Norian near to this level in Europe, North America and probably NE Asia; 2) Halobia austriaca is widely distributed in all paleolatitudes and is a long-established taxon

    Early influences on cardiovascular and renal development

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    The hypothesis that a developmental component plays a role in subsequent disease initially arose from epidemiological studies relating birth size to both risk factors for cardiovascular disease and actual cardiovascular disease prevalence in later life. The findings that small size at birth is associated with an increased risk of cardiovascular disease have led to concerns about the effect size and the causality of the associations. However, recent studies have overcome most methodological flaws and suggested small effect sizes for these associations for the individual, but an potential important effect size on a population level. Various mechanisms underlying these associations have been hypothesized, including fetal undernutrition, genetic susceptibility and postnatal accelerated growth. The specific adverse exposures in fetal and early postnatal life leading to cardiovascular disease in adult life are not yet fully understood. Current studies suggest that both environmental and genetic factors in various periods of life may underlie the complex associations of fetal growth retardation and low birth weight with cardiovascular disease in later life. To estimate the population effect size and to identify the underlying mechanisms, well-designed epidemiological studies are needed. This review is focused on specific adverse fetal exposures, cardiovascular adaptations and perspectives for new studies. Copyrigh

    Early influences on cardiovascular and renal development

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    RECONSTRUCTION OF THE MULTIELEMENT APPARATUS OF THE CONODONT GLADIGONDOLELLA TETHYDIS (HUCKRIEDE) USING MULTIVARIATE STATISTICAL ANALYSIS; IMPLICATIONS FOR TAXONOMY, STRATIGRAPHY, AND EVOLUTION

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    The multielement apparatus of the Spathian (late Early Triassic) to Carnian (early Late Triassic) conodont Gladigondolella tethydis (Huckriede, 1958) is reconstructed here using multivariate statistical analysis to determine the co-occurrence of elements previously assigned to the Gl. tethydis apparatus by other authors. Disagreements on the apparatus composition of Gl. tethydis have focussed around whether or not the species contained two pairs of P2 elements, or only one pair. Some reconstructions consider elements referred to Cratognathodus as belonging to the multielement apparatus of Gladigondolella, whereas other workers consider these elements to belong to their own multielement apparatus. In the absence of fused clusters or bedding plane assemblages, multivariate statistical analysis of isolated elements provides the best method for constraining apparatus composition. Examination of collections from the Anisian (early Middle Triassic) of China and Romania, together with published occurrences from the Anisian and Carnian from around the world, has allowed the development of a database for both abundance and presence/absence of elements assigned to the Gladigondolella tethydis apparatus. Bray-Curtis indices for abundance data and Jaccard indices for presence/absence data both demonstrate that Cratognathodus elements occur as frequently with other elements belonging to the Gladigondolella tethydis apparatus as those elements do with each other. This lends support to the hypothesis that Cratognathodus elements also belong to the Gladigondolella tethydis apparatus. Therefore, the Gladigondolella tethydis apparatus proposed herein consists of the following elements: Gladigondolella tethydis (P1); Cratognathodus sp. (P2a): Ozarkodina saginata (Huckriede, 1958) (P2b); Roundya lautissima (Huckriede, 1958) (S0); Lonchodina spengleri (Huckriede, 1958) (S1); an enantiognathid element (S2); Hindeodella petrae-viridis (Huckriede, 1958) (S3); Hindeodella multihamata (Huckriede, 1958) (S4); and Lonchodina venusta (Huckriede, 1958) (M). Several of the elements assigned to the apparatus exhibit morphological variability, including the P1 element of Gladigondolella tethydis

    Biostratigraphy and sedimentology of Triassic hydrocarbon-bearing rocks in northeastern British Columbia

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    The Triassic Montney and Doig formations in the subsurface of northeastern British Columbia are important hydrocarbon reserves for the province. However the age and tectonic setting of these formations, and their outcrop equivalents (Grayling, Toad and Liard formations), are poorly constrained. The collection of conodont and detrital zircon samples from outcrop sections, and from core taken from subsurface hydrocarbon wells, has allowed the biostratigraphy of these formations to be improved, and the tectonic setting to be inferred. The study of new conodont samples, together with re-examination of existing collections, has led to the recognition of more than thirty new species and morphotypes within the Anisian (Middle Triassic) of British Columbia. These new taxa have in turn allowed the recognition of 11 new faunal assemblages that further refine the conodont biostratigraphic scale for the Anisian of British Columbia. Conodont biostratigraphy of the Montney and Doig formations in the subsurface has allowed correlation of these formations with those of surface sections, and also for the first time provided an age for the boundary between them. The boundary is recognised to be diachronous, and it is oldest in the centre of the study area. The basal Doig Formation is condensed, and shows most condensation at the edges of the study area. Both observations imply the presence of palaeo-highs to the west as well as to the east during the Triassic. This conclusion is supported by detrital zircon geochronology, which demonstrates the presence of sediment derived from the Arctic and from the pericratonic Yukon-Tanana terrane in the Triassic rocks of northeastern British Columbia. Previous hypotheses of Permo-Triassic accretion of this terrane onto the North American margin (the Klondike Orogeny) are supported by this study, and the Triassic sediments of northeastern British Columbia are interpreted to have been deposited in the foreland basin of this orogeny. Science, Faculty ofEarth, Ocean and Atmospheric Sciences, Department ofGraduat

    Downslope re-sedimentation from a short-living carbonate platform: Record from the Upper Triassic Hosselkus limestone (Northern California)

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    Despite their discontinuous occurrence and poor preservation, knowledge about Triassic carbonates from North America has increased considerably during recent years. Their characterization represents a uniqueway to better assess evolution and recovery of the biosphere after the major Permo-Triassic biological crisis in the Panthalassa Ocean. The Eastern Klamath terrane, located in Northern California, is a key terrane due to its geographic position. It is placed halfway between the terranes of the Canadian Cordillera and the Northern Mexico counterparts, both extensively studied and characterized in recent decades, leaving a gap in knowledge along the Pacific coast of the United States. A few kilometers north-east of Redding, Shasta County, California, Upper Triassic carbonates (i.e., the Hosselkus limestone) crop out as a narrow north–south belt about 20 km long, near the artificial reservoir of Lake Shasta. All the accessible localities in this region have been extensively sampled for microfacies and micropaleontological analysis, leading to new insights about the depositional condition and age of the Hosselkus limestone. A depositional model has been proposed for the first time, corresponding to a steep slope system subjected to platform progradation and collapse, recording shallow water facies and associated fauna in the form of calcareous breccia. Numerous conodont specimens have dated the whole succession as Upper Carnian. Identification of shallow water organisms, associated to a reliable stratigraphic interval, allowed comparison of the Hosselkus limestone with other Upper Triassic carbonates from the Panthalassan domain. Despite the faunal affinities, especially with buildups developed at middle-paleolatitudes, the Hosselkus limestone is among the oldest of the terrane-based carbonates in Eastern Panthalassa. Thanks to peculiar geodynamical and bathymetrical conditions, allowing carbonate deposition slightly earlier than in other terranes, the Hosselkus limestone probably acted like a pioneer reef and may have had a great influence in the further expansion of carbonate buildups in the eastern part of the Panthalassa Ocean

    Siliciclastic input controlling carbonate deposition on a low-angle ramp system: New insight from the Upper Triassic Luning Formation (Western-Central Nevada)

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    Although more than one century has passed since the first studies, knowledge about the Upper Triassic shallow-water carbonates from the Panthalassa Ocean remains lower than their Tethyan counterparts. Characterising these sedimentary rocks represents a unique way to deepen our understanding of the biosphere's evolution and recovery after the major Permian–Triassic biological crisis. The Triassic Luning Formation in Western–Central Nevada is a crucial sedimentary succession due to its considerable thickness and areal extent. Among the three members forming the Luning Formation, the present study has only described the upper one in detail due to the minor areal distribution of the Lower Member and the pure siliciclastic nature of the middle Member. All accessible localities in this region, 21 in total, have been extensively sampled for facies and micropalaeontological analyses, including conodonts and poorly preserved foraminifera, leading to new insights about the depositional conditions and exact age of the Luning Formation's Upper Member. A depositional model is proposed for the first time, corresponding to a low-angle ramp with homogeneous bathymetric and hydrodynamic conditions subjected to frequent siliciclastic input from the continent. The regular terrigenous influx causes a significant cyclicity in this portion of the formation, comprising heterogeneously thick limestone beds. The environment-diagnostic fauna is characterised by pioneer organisms that regenerate carbonate production after the main break related to the pure siliciclastic Middle Member's deposition. Numerous conodont specimens indicate that the entire Upper Member is middle Norian in age. Identifying the observed organisms, tied to a reliable stratigraphic interval, allows comparing the Luning Formation with other Upper Triassic carbonates from the Panthalassa Ocean, now cropping out at different latitudes on the eastern and western coasts of the Pacific Ocean. Despite some faunal affinities, especially with carbonate build-ups developed at middle-palaeolatitudes the Luning Formation differs from most other East Panthalassa carbonates because of its short palaeo-distance from the continent (i.e. the American craton), being deposited near the mainland coast instead of on an isolated volcanic arc

    Exploring the psychological health of emergency dispatch centre operatives: a systematic review and narrative synthesis

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    Background. The study objective was to investigate and synthesize available evidence relating to the psychological health of Emergency Dispatch Centre (EDC) operatives, and to identify key stressors experienced by EDC operatives. Methods. Eight electronic databases (Embase, PubMed, Medline, CINAHL, PsycInfo, PsycArticles, The Psychology and Behavioural Sciences Collection, and Google Scholar) were searched. All study designs were included, and no date limits were set. Studies were included if they were published in English, and explored the psychological health of any EDC operatives, across fire, police, and emergency medical services. Studies were excluded if they related solely to other emergency workers, such as police officers or paramedics. Methodological quality of included studies was assessed using checklists adapted from the Critical Appraisal Skills Programme. A narrative synthesis was conducted, using thematic analysis. Results. A total of 16 articles were included in the review. Two overarching themes were identified during the narrative synthesis: `Organisational and Operational Factors' and `Interactions with Others'. Stressors identified included being exposed to traumatic calls, lacking control over high workload, and working in under-resourced and pres- sured environments. Lack of support from management and providing an emotionally demanding service were additional sources of stress. Peer support and social support from friends and family were helpful in managing work-related stress. Discussion. EDC operatives experience stress as a result of their work, which appears to be related to negative psychological health outcomes. Future research should explore the long-term effects of this stress, and the potential for workplace interventions to alleviate the negative impacts on psychological health.</p
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