226 research outputs found

    The Influence of Different Obturation Systems on the Fracture Resistance of Endodontically Treated Roots. An in Vitro Study

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    This study aimed to compare the fracture resistance of endodontically treated roots filled by different obturation systems. Material and methods: Ninety-six upper central incisors were used and decoronated, retaining 12 mm of the roots. On the basis of obturation systems, the roots were divided into 4 groups (n=24): Group1 (COGR): control group (unprepared, unfilled), Group 2 (AVGR): ActiV GP points/ActiV GP sealer, Group3 (GPGR): Gutta percha points/AH plus sealer, and Group4 (GAGR): Gutta percha points/ActiV GP sealer. The last three groups were obturated with the single cone technique. The roots were then stored in 100% relative humidity at 37 °C for 2 weeks. A vertical compressive force was exerted with a universal testing machine until a fracture occurred. Data were statistically analyzed with one-way ANOVA. Results: Mean (SD) failure loads for groups ranged from 920.51 ± 210.37 to 1113.44 ± 489.42 N. The fracture resistance between the different study groups indicated no statistical difference. Conclusions: ActiV GP system did not exert a significant effect on the fracture resistance of endodontically treated teeth

    Rubber Bullets and the Black Lives Matters Protests

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    Academic Freedom Post-9/11

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    Academic freedom in the United States is facing its most important threat since the McCarthy era of the 1950s. In the aftermath of 11 September 2001, government agencies and private organizations have been subjecting universities to an increasingly sophisticated infrastructure of surveillance, intervention, and control. In the name of the war against terrorism, civil liberties have been seriously eroded, open debate limited, and dissent stifled

    Culture and efficacy of performance management: a qualitative study in Thailand

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    Globalisation has led an increasing adoption of Western modelled Performance Management (PM) systems in non-Western countries, particularly Asia. The aim of the research is to explore the effects of Thai culture on the efficacy of Western modelled performance management (PM) in a cross-cultural setting. Thailand is becoming increasingly important to Australian businesses, particularly in view of the ASEAN Economic Community Plan, which is now in its final stages implementation. The primary data for this study was sourced from 43 semi-structured and in-depth interviews with 30 participants. The participants occupied managerial positions ranging from CEO executives to middle management, with organisations operating in Thailand. The interviews were conducted with both expatriate and local Thai employees. Social constructivism, qualitative methodology, and inductive reasoning were applied to the collection, analysis and interpretation of the data. The findings show only a tenuous link between Western values, upon which PM systems are predicated, and motivational values of the host society. As a consequence, Western PM practice can fail to adequately compensate for differing cultural concepts of the means-action-ends relationship that constitutes efficacy, which, in turn, affects the efficacy of PM outcomes. This research has implications for future cross-cultural management studies by expanding the perspectives of inquiry through cultural constructs of efficacy. It also has implications for PM design, and employee cultural awareness training and development. This will assist expatriate and host country management, to compromise cultural values differences. In doing so, closer alignment of expectations may be achieved, within the organisation-manager-subordinate relationships, to deliver efficacious PM outcomes

    A Wooly Way? Fiber technologies and cultures 3,000-years-ago along the Inner Asian Mountain Corridor

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    Wool-focused economies yielded a pastoralist materiality that visibly shaped the lived experiences of Central Asian populations today. In this paper, we investigate the earlier application of fibers through a key mountain corridor for social interactions during Prehistory. We focus on the site of Chap 1 located in the highlands of the Tien Shan Mountains of Kyrgyzstan where researchers have found a complex agropastoral subsistence culture was established from at least ca. 3,000 BCE. The perishable materials that would have accompanied the early spread of cultural and technological traditions related to fiber-based crafts throughout this area are under-documented due to poor organic preservation. Hence, there has been little consideration of the role that textiles played in highland occupation and how woven fabrics might have facilitated settlement in the extreme climates of Central Asia. We address this ongoing problem through a multi-application survey of Chap’s unpublished textile evidence preserved as impressions in coarseware ceramics of its Final Bronze Age. We consider evidence that sheep wool formed a key cultural adaptation for surviving the extreme winters of Central Asia’s highland regions

    Early integration of pastoralism and millet cultivation in Bronze Age Eurasia

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    https://royalsocietypublishing.org/doi/10.1098/rspb.2019.1273Mobile pastoralists are thought to have facilitated the first trans-Eurasian dispersals of domesticated plants during the Early Bronze Age (ca 2500–2300 BC). Problematically, the earliest seeds of wheat, barley and millet in Inner Asia were recovered from human mortuary contexts and do not inform on local cultivation or subsistence use, while contemporaneous evidence for the use and management of domesticated livestock in the region remains ambiguous. We analysed mitochondrial DNA and multi-stable isotopic ratios (δ13C, δ15N and δ18O) of faunal remains from key pastoralist sites in the Dzhungar Mountains of southeastern Kazakhstan. At ca 2700 BC, Near Eastern domesticated sheep and goat were present at the settlement of Dali, which were also winter foddered with the region's earliest cultivated millet spreading from its centre of domestication in northern China. In the following centuries, millet cultivation and caprine management became increasingly intertwined at the nearby site of Begash. Cattle, on the other hand, received low levels of millet fodder at the sites for millennia. By primarily examining livestock dietary intake, this study reveals that the initial transmission of millet across the mountains of Inner Asia coincided with a substantial connection between pastoralism and plant cultivation, suggesting that pastoralist livestock herding was integral for the westward dispersal of millet from farming societies in China

    Investigation of the influence of a glutathione S-transferase metabolic resistance to pyrethroids/DDT on mating competitiveness in males of the African malaria vector, Anopheles funestus [version 2; peer review: 1 approved, 2 approved with reservations]

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    Background: Metabolic resistance is a serious challenge to current insecticide-based interventions. The extent to which it affects natural populations of mosquitoes including their reproduction ability remains uncharacterised. Here, we investigated the potential impact of the glutathione S-transferase L119F-GSTe2 resistance on the mating competitiveness of male Anopheles funestus, in Cameroon. Methods: Swarms and indoor resting collections took place in March, 2018 in Tibati, Cameroon. WHO tube and cone assays were performed on F1 mosquitoes from indoor collected females to assess the susceptibility profile of malaria vectors. Mosquitoes mated and unmated males collected in the swarms were genotyped for the L119F metabolic marker to assess its association with mating male competitiveness. Results: Susceptibility and synergist assays, showed that this population was multiple resistant to pyrethroids, DDT and carbamates, likely driven by metabolic resistance mechanisms. Cone assays revealed a reduced efficacy of standard pyrethroid-nets (Olyset and PermaNet 2.0) with low mortality (80%). The L119F-GSTe2 mutation, conferring pyrethroid/DDT resistance, was detected in this An. funestus population at a frequency of 28.8%. In addition, a total of 15 mating swarms were identified and 21 An. funestus couples were isolated from those swarms.  A comparative genotyping of the L119F-GSTe2 mutation between mated and unmated males revealed that heterozygote males 119L/F-RS were less able to mate than homozygote susceptible (OR=7.2, P<0.0001). Surprisingly, heterozygote mosquitoes were also less able to mate than homozygote resistant (OR=4.2, P=0.010) suggesting the presence of a heterozygote disadvantage effect. Overall, mosquitoes bearing the L119-S susceptible allele were significantly more able to mate than those with 119F-R resistant allele (OR=2.1, P=0.03). Conclusion: This study provides preliminary evidences that metabolic resistance potentially exerts a fitness cost on mating competiveness in resistant mosquitoes

    High mitochondrial diversity of domesticated goats persisted among Bronze and Iron Age pastoralists in the Inner Asian Mountain Corridor

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    Goats were initially managed in the Near East approximately 10,000 years ago and spread across Eurasia as economically productive and environmentally resilient herd animals. While the geographic origins of domesticated goats (Capra hircus) in the Near East have been long-established in the zooarchaeological record and, more recently, further revealed in ancient genomes, the precise pathways by which goats spread across Asia during the early Bronze Age (ca. 3000 to 2500 cal BC) and later remain unclear. We analyzed sequences of hypervariable region 1 and cytochrome b gene in the mitochondrial genome (mtDNA) of goats from archaeological sites along two proposed transmission pathways as well as geographically intermediary sites. Unexpectedly high genetic diversity was present in the Inner Asian Mountain Corridor (IAMC), indicated by mtDNA haplotypes representing common A lineages and rarer C and D lineages. High mtDNA diversity was also present in central Kazakhstan, while only mtDNA haplotypes of lineage A were observed from sites in the Northern Eurasian Steppe (NES). These findings suggest that herding communities living in montane ecosystems were drawing from genetically diverse goat populations, likely sourced from communities in the Iranian Plateau, that were sustained by repeated interaction and exchange. Notably, the mitochondrial genetic diversity associated with goats of the IAMC also extended into the semi-arid region of central Kazakhstan, while NES communities had goats reflecting an isolated founder population, possibly sourced via eastern Europe or the Caucasus region

    Seroprevalence of Rift Valley fever virus in domestic ruminants of various origins in two markets of Yaoundé, Cameroon

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    Background: Rift Valley fever (RVF) is a mosquito-borne zoonosis endemic in Africa. With little known of the burden or epidemiology of RVF virus (RVFV) in Cameroon, this study aimed to determine the seroprevalence of RVFV in domestic ruminants of various origins in two markets of Yaoundé, Cameroon. Methodology/Principal findings: The origin of animals randomly sampled at two livestock markets in Yaoundé were recorded and plasma samples collected for competitive and capture Enzyme-linked Immunosorbent Assay (ELISA) to determine the prevalence of Immunoglobulins G (IgG) and Immunoglobulins M (IgM) antibodies. Following ELISA IgM results, a real-time reverse transcription-polymerase chain reaction (qRT-PCR) was performed to detect RVFV RNA. In June-August 2019, February-March 2020, and March-April 2021, 756 plasma samples were collected from 441 cattle, 168 goats, and 147 sheep. RVFV IgG seroprevalence was 25.7% for all animals, 42.2% in cattle, 2.7% in sheep, and 2.4% in goats. However, IgM seroprevalence was low, at 0.9% in all animals, 1.1% in cattle, 1.4% in sheep, and 0% in goats. The seroprevalence rates varied according to the animal’s origin with the highest rate (52.6%) in cattle from Sudan. In Cameroon, IgG and IgM rates respectively were 45.1% and 2.8% in the North, 44.8% and 0% in the Adamawa, 38.6% and 1.7% in the Far-North. All IgM positive samples were from Cameroon. In cattle, 2/5 IgM positive samples were also IgG positive, but both IgM positive samples in sheep were IgG negative. Three (42.9%) IgM positive samples were positive for viral RVFV RNA using qRT-PCR but given the high ct values, no amplicon was obtained. Conclusion/Significance: These findings confirm the circulation of RVFV in livestock in Cameroon with prevalence rates varying by location. Despite low IgM seroprevalence rates, RVF outbreaks can occur without being noticed. Further epidemiological studies are needed to have a broad understanding of RVFV transmission in Cameroon

    Possible Detection of Low Energy Solar Neutrons Using Boron Based Materials

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    Solar neutrons have been detected aboard the International Space Station (ISS), using lithium tetraborate and boron carbide detector elements. We find that evidence of a solar neutron flux, as detected in a neutron calorimeter following subtraction of the proton background, with an energy of about 2 to 4 MeV. This solar neutron flux is likely no more than 250 to 375 neutrons cm−2sec−1, with a lower bound of 50–75 neutrons cm−2sec−1 at one au
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