65 resultados para late Roman
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Fossils and sediments preserved in caves are an excellent source of information for investigating impacts of past environmental changes on biodiversity. Until recently studies have relied on morphology-based palaeontological approaches, but recent advances in molecular analytical methods offer excellent potential for extracting a greater array of biological information from these sites. This study presents a thorough assessment of DNA preservation from late Pleistocene–Holocene vertebrate fossils and sediments from Kelly Hill Cave Kangaroo Island, South Australia. Using a combination of extraction techniques and sequencing technologies, ancient DNA was characterised from over 70 bones and 20 sediment samples from 15 stratigraphic layers ranging in age from >20 ka to ∼6.8 ka. A combination of primers targeting marsupial and placental mammals, reptiles and two universal plant primers were used to reveal genetic biodiversity for comparison with the mainland and with the morphological fossil record for Kelly Hill Cave. We demonstrate that Kelly Hill Cave has excellent long-term DNA preservation, back to at least 20 ka. This contrasts with the majority of Australian cave sites thus far explored for ancient DNA preservation, and highlights the great promise Kangaroo Island caves hold for yielding the hitherto-elusive DNA of extinct Australian Pleistocene species.
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The thick piles of late-Archean volcaniclastic sedimentary successions that overlie the voluminous greenstone units of the eastern Yilgarn Craton, Western Australia, record the important transition from the cessation in mafic-ultramafic volcanism to cratonisation between about 2690 and 2655 Ma. Unfortunately, an inability to clearly subdivide the superficially similar sedimentary successions and correlate them between the various geological terranes and domains of the eastern Yilgarn Craton has led to uncertainty about the timing and nature of the region's palaeogeographic and palaeotectonic evolution. Here, we present the results of some 2025 U–Pb laser-ablation-ICP-MS analyses and 323 Sensitive High-Resolution Ion Microprobe (SHRIMP) analyses of detrital zircons from 14 late-Archean felsic clastic successions of the eastern Yilgarn Craton, which have enabled correlation of clastic successions. The results of our data, together with those compiled from previous studies, show that the post-greenstone sedimentary successions include two major cycles that both commenced with voluminous pyroclastic volcanism and ended with widespread exhumation and erosion associated with granite emplacement. Cycle One commences with an influx of rapidly reworked feldspar-rich pyroclastic debris. These units, here-named the Early Black Flag Group, are dominated by a single population of detrital zircons with an average age of 2690–2680 Ma. Thick (up to 2 km) dolerite bodies, such as the Golden Mile Dolerite, intrude the upper parts of the Early Black Flag Group at about 2680 Ma. Incipient development of large granite domes during Cycle One created extensional basins predominantly near their southeastern and northwestern margins (e.g., St Ives, Wallaby, Kanowna Belle and Agnew), into which the Early Black Flag Group and overlying coarse mafic conglomerate facies of the Late Black Flag Group were deposited. The clast compositions and detrital-zircon ages of the late Black Flag Group detritus match closely the nearby and/or stratigraphically underlying successions, thus suggesting relatively local provenance. Cycle Two involved a similar progression to that observed in Cycle One, but the age and composition of the detritus were notably different. Deposition of rapidly reworked quartz-rich pyroclastic deposits dominated by a single detrital-zircon age population of 2670–2660 Ma heralded the beginning of Cycle Two. These coarse-grained quartz-rich units, are name here the Early Merougil Group. The mean ages of the detrital zircons from the Early Merougil Group match closely the age of the peak in high-Ca (quartz-rich) granite magmatism in the Yilgarn Craton and thus probably represent the surface expression of the same event. Successions of the Late Merougil Group are dominated by coarse felsic conglomerate with abundant volcanic quartz. Although the detrital zircons in these successions have a broad spread of age, the principal sub-populations have ages of about 2665 Ma and thus match closely those of the Early Merougil Group. These successions occur most commonly at the northwestern and southeastern margins of the granite batholiths and thus are interpreted to represent resedimented units dominted by the stratigraphically underlying packages of the Early Merougil Group. The Kurrawang Group is the youngest sedimentary units identified in this study and is dominated by polymictic conglomerate with clasts of banded iron formation (BIF), granite and quartzite near the base and quartz-rich sandstone units containing detrital zircons aged up to 3500 Ma near the top. These units record provenance from deeper and/or more-distal sources. We suggest here that the principal driver for the major episodes of volcanism, sedimentation and deformation associated with basin development was the progressive emplacement of large granite batholiths. This interpretation has important implication for palaeogeographic and palaeotectonic evolution of all late-Archean terranes around the world.
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Young people’s participation in science, technology, engineering and mathematics (STEM) is a matter of international concern. Studies and careers that require physical sciences and advanced mathematics are most affected by the problem and women in particular are under-represented in many STEM fields. This article views international research about young people’s relationships to, and participation in, STEM subjects and careers through the lens of an expectancy value model of achievement-related choices. In addition it draws on sociological theories of late-modernity and identity, which situate decision-making in a cultural context. The article examines how these frameworks are useful in explaining the decisions of young people – and young women in particular – about participating in STEM and proposes possible strategies for removing barriers to participation.
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Violence in entertainment districts is a major problem across urban landscapes throughout the world. Research shows that licensed premises are the third most common location for homicides and serious assaults, accounting for one in ten fatal and nonfatal assaults. One class of interventions that aims to reduce violence in entertainment districts involves the use of civil remedies: a group of strategies that use civil or regulatory measures as legal “levers” to reduce problem behavior. One specific civil remedy used to reduce problematic behavior in entertainment districts involves manipulation of licensed premise trading hours. This article uses generalized linear models to analyze the impact of lockout legislation on recorded violent offences in two entertainment districts in the Australian state of Queensland. Our research shows that 3 a.m. lockout legislation led to a direct and significant reduction in the number of violent incidents inside licensed premises. Indeed, the lockouts cut the level of violent crime inside licensed premises by half. Despite these impressive results for the control of violence inside licensed premises, we found no evidence that the lockout had any impact on violence on streets and footpaths outside licensed premises that were the site for more than 80 percent of entertainment district violence. Overall, however, our analysis suggests that lockouts are an important mechanism that helps to control the level of violence inside licensed premises but that finely grained contextual responses to alcohol-related problems are needed rather than one-size-fits-all solutions.
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Marine sediments around volcanic islands contain an archive of volcaniclastic deposits, which can be used to reconstruct the volcanic history of an area. Such records hold many advantages over often incomplete terrestrial datasets. This includes the potential for precise and continuous dating of intervening sediment packages, which allow a correlatable and temporally-constrained stratigraphic framework to be constructed across multiple marine sediment cores. Here, we discuss a marine record of eruptive and mass-wasting events spanning ~250 ka offshore of Montserrat, using new data from IODP Expedition 340, as well as previously collected cores. By using a combination of high-resolution oxygen isotope stratigraphy, AMS radiocarbon dating, biostratigraphy of foraminifera and calcareous nannofossils and clast componentry, we identify five major events at Soufriere Hills volcano since 250 ka. Lateral correlation of these events across sediment cores collected offshore of the south and south west of Montserrat, have improved our understanding of the timing, extent and associations between events in this area. Correlations reveal that powerful and potentially erosive density-currents travelled at least 33 km offshore, and demonstrate that marine deposits, produced by eruption-fed and mass-wasting events on volcanic islands, are heterogeneous in their spatial distribution. Thus, multiple drilling/coring sites are needed to reconstruct the full chronostratigraphy of volcanic islands. This multidisciplinary study will be vital to interpreting the chaotic records of submarine landslides at other sites drilled during Expedition 340 and provides a framework that can be applied to the stratigraphic analysis of sediments surrounding other volcanic islands.
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Purpose To report an unusual case of a late-stage reactivation of immune stromal keratitis associated with herpes zoster ophthalmicus (HZO), occurring without any apparent predisposing factors, more than 4 years after an acute zoster dermatomal rash. Significant corneal hypoesthesia and a central band keratopathy developed within 6 months of the late-stage reactivation. The clinical case management, issues associated with management, and management options are discussed, including the use of standardized, regulatory approved, antibacterial medical honey. Case Report An 83-year-old woman presented for routine review with a reactivation of right anterior stromal keratitis and mild anterior uveitis, occurring more than 4 years after an acute HZO dermatomal rash and an associated initial episode of anterior stromal keratitis. Corneal sensation became markedly impaired, and over the subsequent 6 months, a right central band keratopathy developed despite oral antiviral and topical steroid therapy. Visual acuity with pinhole was reduced to 20/100 in the affected eye and moderate irritation and epiphora were experienced. The patient declined the surgical intervention options of chelation, lamellar keratectomy, and phototherapeutic keratectomy to treat the band keratopathy. Longer-term management has involved preservative-free artificial tears, eyelid hygiene, standardized antibacterial medical honey, topical nonpreserved steroid, and UV-protective wraparound sunglasses. The clinical condition has improved over 14 months with this ocular surface management regimen, and visual acuity of 20/30 is currently achieved in a comfortable eye. Conclusions The chronic and recurrent nature of HZO can be associated with significant corneal morbidity, even many years after the initial zoster episode. Long-term review and management of patients with a history of herpes zoster stromal keratitis are indicated following the initial corneal involvement. Standardized antibacterial medical honey can be considered in the management of the chronic ocular surface disease associated with HZO and warrants further evaluation in clinical trials.
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We identified, mapped, and characterized a widespread area (gt;1,020 km2) of patterned ground in the Saginaw Lowlands of Michigan, a wet, flat plain composed of waterlain tills, lacustrine deposits, or both. The polygonal patterned ground is interpreted as a possible relict permafrost feature, formed in the Late Wisconsin when this area was proximal to the Laurentide ice sheet. Cold-air drainage off the ice sheet might have pooled in the Saginaw Lowlands, which sloped toward the ice margin, possibly creating widespread but short-lived permafrost on this glacial lake plain. The majority of the polygons occur between the Glacial Lake Warren strandline (~14.8 cal. ka) and the shoreline of Glacial Lake Elkton (~14.3 cal. ka), providing a relative age bracket for the patterned ground. Most of the polygons formed in dense, wet, silt loam soils on flat-lying sites and take the form of reticulate nets with polygon long axes of 150 to 160 m and short axes of 60 to 90 m. Interpolygon swales, often shown as dark curvilinears on aerial photographs, are typically slightly lower than are the polygon centers they bound. Some portions of these interpolygon swales are infilled with gravel-free, sandy loam sediments. The subtle morphology and sedimentological characteristics of the patterned ground in the Saginaw Lowlands suggest that thermokarst erosion, rather than ice-wedge replacement, was the dominant geomorphic process associated with the degradation of the Late-Wisconsin permafrost in the study area and, therefore, was primarily responsible for the soil patterns seen there today.
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The objective of this study is to examine technical efficiency and productivity growth in the Indian banking sector over the period from 2004 to 2011. We apply an innovative methodological approach introduced by Chen et al. (2011) and Barros et al. (2012), who use a weighted Russell directional distance model to measure technical inefficiency. We further modify and extend that model to measure TFP change with NPLs. We find that the inefficiency levels are significantly different among the three ownership structure of banks in India. Foreign banks have strong market position in India and they pull the production frontier in a more efficient direction. SPBs and domestic private banks show considerably higher inefficiency. We conclude that the restructuring policy applied in the late 1990s and early 2000s by the Indian government has not had a long-lasting effect.
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This thesis investigated, for the first time, the prevalence of Ureaplasma species infection within the placentae of women who delivered in the late preterm stages of pregnancy. The presence of these microorganisms was associated with either severe inflammation within the placenta or, for some women, there were no pregnancy complications and these women delivered at term. Ureaplasmas are able to vary their surface exposed lipoproteins and we demonstrated that different host immune responses were generated in vivo to different sized surface lipoproteins. This may explain why ureaplasma infections do not always result in adverse pregnancy and neonatal outcomes.
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A 2400 year record of environmental change is reported from a wetland on Bentinck Island in the southern Gulf of Carpentaria, northern Australia. Three phases of wetland development are identified, with a protected coastal setting from ca. 2400 to 500 years ago, transitioning into an estuarine mangrove forest from ca. 500 years ago to the 1940s, and finally to a freshwater swamp over the past +60 years. This sequence reflects the influence of falling sea-levels, development of a coastal dune barrier system, prograding shorelines, and an extreme storm (cyclone) event. In addition, there is clear evidence of the impacts that human abandonment and resettlement have on the island's fire regimes and vegetation. A dramatic increase in burning and vegetation thickening was observed after the cessation of traditional Indigenous Kaiadilt fire management practices in the 1940s, and was then reversed when people returned to the island in the 1980s. In terms of the longer context for human occupation of the South Wellesley Archipelago, it is apparent that the mangrove phase provided a stable and productive environment that was conducive for human settlement of this region over the past 1000 years.
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Objective Diagnosing attention deficit hyperactivity disorder (ADHD) in adults is difficult when diagnosticians cannot establish an onset before the DSM-IV criterion of age 7 or if the number of symptoms recalled does not achieve DSM’s diagnosis threshold. Method The authors addressed the validity of DSM-IV’s age-at-onset and symptom threshold criteria by comparing four groups of adults: 127 subjects with full ADHD who met all DSM-IV criteria for childhood-onset ADHD, 79 subjects with late-onset ADHD who met all criteria except the age-at-onset criterion, 41 subjects with subthreshold ADHD who did not meet full symptom criteria for ADHD, and 123 subjects without ADHD who did not meet any criteria. The authors hypothesized that subjects with late-onset and subthreshold ADHD would show patterns of psychiatric comorbidity, functional impairment, and familial transmission similar to those seen in subjects with full ADHD. Result Subjects with late-onset and full ADHD had similar patterns of psychiatric comorbidity, functional impairment, and familial transmission. Most children with late onset of ADHD (83%) were younger than 12. Subthreshold ADHD was milder and showed a different pattern of familial transmission than the other forms of ADHD. Conclusions The data about the clinical features of probands and the pattern of transmission of ADHD among relatives found little evidence for the validity of subthreshold ADHD among such subjects, who reported a lifetime history of some symptoms that never met DSM-IV’s threshold for diagnosis. In contrast, the results suggested that late-onset adult ADHD is valid and that DSM-IV’s age-at-onset criterion is too stringent.
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Background Diagnosing attention-deficit/hyperactivity disorder (ADHD) in adults is difficult when the diagnostician cannot establish an onset prior to the DSM-IV criterion of age 7 or if the number of symptoms recalled does not achieve the DSM-IV threshold for diagnosis. Because neuropsychological deficits are associated with ADHD, we addressed the validity of the DSM-IV age at onset and symptom threshold criteria by using neuropsychological test scores as external validators. Methods We compared four groups of adults: 1) full ADHD subjects met all DSM-IV criteria for childhood-onset ADHD; 2) late-onset ADHD subjects met all criteria except the age at onset criterion; 3) subthreshold ADHD subjects did not meet full symptom criteria; and 4) non-ADHD subjects did not meet any of the above criteria. Results Late-onset and full ADHD subjects had similar patterns of neuropsychological dysfunction. By comparison, subthreshold ADHD subjects showed few neuropsychological differences with non-ADHD subjects. Conclusions Our results showing similar neuropsychological underpinning in subjects with late-onset ADHD suggest that the DSM-IV age at onset criterion may be too stringent. Our data also suggest that ADHD subjects who failed to ever meet the DSM-IV threshold for diagnosis have a milder form of the disorder.