378 research outputs found

    The Role of Legal Services in the Antipoverty Program

    Get PDF
    Large-scale adaptive radiations might explain the runaway success of a minority of extant vertebrate clades. This hypothesis predicts, among other things, rapid rates of morphological evolution during the early history of major groups, as lineages invade disparate ecological niches. However, few studies of adaptive radiation have included deep time data, so the links between extant diversity and major extinct radiations are unclear. The intensively studied Mesozoic dinosaur record provides a model system for such investigation, representing an ecologically diverse group that dominated terrestrial ecosystems for 170 million years. Furthermore, with 10,000 species, extant dinosaurs (birds) are the most speciose living tetrapod clade. We assembled composite trees of 614-622 Mesozoic dinosaurs/birds, and a comprehensive body mass dataset using the scaling relationship of limb bone robustness. Maximum-likelihood modelling and the node height test reveal rapid evolutionary rates and a predominance of rapid shifts among size classes in early (Triassic) dinosaurs. This indicates an early burst niche-filling pattern and contrasts with previous studies that favoured gradualistic rates. Subsequently, rates declined in most lineages, which rarely exploited new ecological niches. However, feathered maniraptoran dinosaurs (including Mesozoic birds) sustained rapid evolution from at least the Middle Jurassic, suggesting that these taxa evaded the effects of niche saturation. This indicates that a long evolutionary history of continuing ecological innovation paved the way for a second great radiation of dinosaurs, in birds. We therefore demonstrate links between the predominantly extinct deep time adaptive radiation of non-avian dinosaurs and the phenomenal diversification of birds, via continuing rapid rates of evolution along the phylogenetic stem lineage. This raises the possibility that the uneven distribution of biodiversity results not just from large-scale extrapolation of the process of adaptive radiation in a few extant clades, but also from the maintenance of evolvability on vast time scales across the history of life, in key lineages

    Fluoridated elastomers: Effect on the microbiology of plaque

    Get PDF
    The objective of this study was to investigate the effect of fluoridated elastomeric ligatures on the microbiology of local dental plaque in vivo. This randomized, prospective, longitudinal, clinical trial had a split-mouth crossover design. The subjects were 30 patients at the beginning of their treatment with fixed orthodontic appliances in the orthodontic departments of the Liverpool and the Sheffield dental hospitals in the United Kingdom. The study consisted of 2 experimental periods of 6 weeks with a washout period between. Fluoridated elastomers were randomly allocated at the first visit to be placed around brackets on tooth numbers 12, 11, 33 or 22, 21, 43. Nonfluoridated elastomers were placed on the contralateral teeth. Standard nonantibacterial fluoridated toothpaste and mouthwash were supplied. After 6 weeks (visit 2), the elastomers were removed, placed in transport media, and plated on agar within 2 hours. Nonfluoridated elastomers were placed on all brackets for 1 visit to allow for a washout period. At visit 3, fluoridated elastomers were placed on the teeth contralateral to those that received them at visit 1. At visit 4, the procedures at visit 2 were repeated. Samples were collected on visits 2 and 4. A logistic regression was performed, with the presence or absence of streptococcal or anaerobic growth as the dependent variable. A mixed-effects analysis of variance was carried out with the percentage of streptococcal or anaerobic bacterial count as the dependent variable. The only significant independent variables were the subject variable (P = < .001) for the percentage of streptococcal and anaerobic bacterial count and the visit variable for the percentage of streptococcal count (P = < .001). The use of fluoridated or nonfluoridated elastomers was not significant for percentage of either streptococcal (P = .288) or anaerobic count (P = .230). Fluoridated elastomers are not effective at reducing local streptococcal or anaerobic bacterial growth after a clinically relevant time in the mouth

    Varied effects of algal symbionts on transcription factor NF-ÎșB in a sea anemone and a coral: possible roles in symbiosis and thermotolerance

    Full text link
    Many cnidarians, including the reef-building corals, undergo symbiotic mutualisms with photosynthetic dinoflagellate algae of the family Symbiodiniaceae. These partnerships are sensitive to temperature extremes, which cause symbiont loss and increased coral mortality. Previous studies have implicated host immunity and specifically immunity transcription factor NF-ÎșB as having a role in the maintenance of the cnidarian-algal symbiosis. Here we have further investigated a possible role for NF-ÎșB in establishment and loss of symbiosis in various strains of the anemone Exaiptasia (Aiptasia) and in the coral Pocillopora damicornis. Our results show that NF-ÎșB expression is reduced in Aiptasia larvae and adults that host certain algae strains. Treatment of Aiptasia larvae with a known symbiosis-promoting cytokine, transforming growth factor ÎČ, also led to decreased NF-ÎșB expression. We also show that aposymbiotic Aiptasia (with high NF-ÎșB expression) have increased survival following infection with the pathogenic bacterium Serratia marcescens as compared to symbiotic Aiptasia (low NF-ÎșB expression). Furthermore, a P. damicornis coral colony hosting Durusdinium spp. (formerly clade D) symbionts had higher basal NF-ÎșB expression and decreased heat-induced bleaching as compared to two individuals hosting Cladocopium spp. (formerly clade C) symbionts. Lastly, genome-wide gene expression profiling and genomic promoter analysis identified putative NF-ÎșB target genes that may be involved in thermal bleaching, symbiont maintenance, and/or immune protection in P. damicornis. Our results provide further support for the hypothesis that modulation of NF-ÎșB and immunity plays a role in some, but perhaps not all, cnidarian-Symbiodiniaceae partnerships as well as in resistance to pathogens and bleaching.Accepted manuscrip

    No difference in surgical outcomes between Open and Closed exposure of palatally displaced maxillary canines

    Get PDF
    Purpose: To investigate differences in the surgical outcomes between Open and Closed exposure for palatally displaced maxillary cuspids (PDC). Methods: A multicenter, RCT involving two parallel groups. The settings were one dental teaching hospital in, and two hospital units near Sheffield, UK. Participants were aged <20 years with a unilateral PDC, who provided informed consent. They were randomly allocated to either receive the Open (O) or the Closed (C) surgical procedure. The outcomes were time spent in the operating room and 10-day post-operative patient questionnaire. Statistical differences between the two techniques were tested using independent t tests for continuous variables and chi-squared tests for frequencies. Results: The final study sample was composed of 71 participants (64% females). There were no differences in the gender ratios (O: F=27, M=13; C: F=25, M=16) or mean ages of the two groups (O: 14.3 yrs SD 1.3; C: 14.1 yrs SD 1.6) at the start. The mean operating times for the Open and Closed techniques were 34.3 mins (SD 11.2) and 34.3 mins (SD 11.9) respectively (p=.986). There were no statistically significant differences between the two treatment groups for any of the patient-assessed outcomes (p>.05). Conclusions: There were no differences in the surgical outcomes investigated in this study between Open and Closed exposure for PDC

    Development and evaluation of a patient decision aid for young people and parents considering fixed orthodontic appliances

    Get PDF
    OBJECTIVES: To develop and evaluate a child-centred patient decision aid for young people, and their parents, supporting shared decision making about fixed orthodontic appliance treatment with dental health professionals, namely the Fixed Appliance Decision Aid (FADA). METHODS: The studies were undertaken in a UK teaching dental hospital orthodontic department in 2013-2014. The development phase involved an interview study with: (a) 10 patients (12-16 years old), and their parents, receiving orthodontic care to investigate treatment decision making and inform the content of the FADA and (b) 23 stakeholders critiquing the draft decision aid's content, structure and utility. The evaluation phase employed a pre-/post-test study design, with 30 patients (12-16 years old) and 30 parents. Outcomes included the Decisional Conflict Scale; measures of orthodontic treatment expectations and knowledge. RESULTS: Qualitative analysis identified two informational needs: effectiveness of treatment on orthodontic outcomes and treatment consequences for patients' lives. Quantitative analysis found decisional conflict reduced in both patients (mean difference -12.3, SD 15.3, 95% CI 6.6-17.9; p < 0.001) and parents (mean difference - 8.6, SD 16.6, 95% CI 2.5-14.8; p = 0.002); knowledge about duration and frequency of orthodontic treatment increased; expectations about care were unchanged. CONCLUSIONS: Using the FADA may enable dental professionals to support patients and their parents, decisions about fixed appliance treatments more effectively, ensuring young people's preferences are integrated into care planning

    Laboratory simulations of fluid-induced seismicity, hydraulic fracture, and fluid flow

    Get PDF
    Fluid-induced seismicity has been observed and recorded for decades. Seismic energy necessarily requires a source, which is frequently related to rock fracture either in compression or tension. In both cases, such fracture may be promoted by crustal fluids. In this paper, we review some of the advances in the field of fluid-induced seismicity, with a particular focus on the use and application of new and innovative laboratory methods to better understand the complex, coupled, processes in shallow sub-surface energy extraction applications. We discuss the current state-of-the-art with specific reference to Thermal-Hydraulic-Coupling in volcanotectonic environments, which has a long history of fluid-driven seismic events linked to deep fluid movement. This ranges from local earthquakes to fluid-driven resonance, known as volcanic tremor. More recently so-called non-volcanic tremor has been identified in a range of scenarios where motion at an interface is primarily driven by fluids rather than significant stress release. Finally, we review rock fracture in the tensile regime which occurs naturally and in the engineered environment for developing fractures for the purpose of resource extraction, such as hydraulic fracturing in unconventional hydrocarbon industry or developing Hot-Dry-Rock geothermal reservoirs

    "Over-reviewing" of research? An analysis of orthodontic reviews

    Get PDF
    INTRODUCTION: Research overviews may be undertaken to identify gaps in the literature, evaluate existing systematic reviews (SRs), and summarize evidence. This paper aims to profile overviews that have been conducted in orthodontics and related interventions since 2012 and to evaluate the degree of overlap among these overviews. METHODS: Overviews published between January 1, 2012 and June 20, 2023 were identified using an electronic search involving Google Scholar and PubMed. A descriptive summary was produced, and citation matrices were used to evaluate the percentage of overlap between overviews using corrected covered area and covered area. This was classified as slight, moderate, high, or very high. RESULTS: A total of 35 overviews were identified across a wide range of topics. Eight overviews included 20 SRs (median no. of SRs per overview, 15; range, 3-62). Meta-analysis was conducted in only 5 overviews. Overlap between overviews on the same topic ranged from slight (2.7%) to very high (53.8%). CONCLUSIONS: Almost all overview topics address treatments and their effects, with a wide variation in the number and quality of SRs included. There is considerable overlap in some orthodontic overviews, suggesting unnecessary duplication and research waste. Researchers should be encouraged to focus on primary data collection to add more high-quality data to SRs, which will ultimately enhance the yield from secondary and tertiary orthodontic research

    Ductile flow in sub-volcanic carbonate basement as the main control for edifice stability:new experimental insights

    Get PDF
    Limestone in volcanic basements has been identified as a hazard in terms of edifice stability due to the propensity of calcite to decompose into lime and CO2 at high temperatures (&gt;600 °C), causing a decrease in mechanical strength. To date, such hypotheses have been tested by experiments performed at ambient pressure. The present work determines the mechanical strength of limestone under sub-volcanic conditions of pressure and temperature and evaluates the effect of calcite decomposition. To this end, we use Mt. Etna as a case study, deforming sub-Etnean carbonate samples under triaxial compression using a Paterson deformation apparatus. We evaluate the effect of thermal decomposition of calcite on sample strength by comparing closed and open systems and measuring the permeability evolution under static conditions. Mechanical and micro-structural observations at a constant strain rate of 10-5 s-1 and at a confining pressure of 50 MPa indicate that the rocks are brittle up to and including 300 °C. At higher temperatures the deformation becomes macroscopically ductile, i.e., deformation is distributed throughout the sample. The brittle to ductile transition is accompanied by an irreversible permeability decrease from 10-17 to 10-19 m2 between 200 and 600 °C. We present new evidence that permanent change in permeability is due to ductile processes closing the initial pore space. Samples deformed at temperatures up to 900 °C do not contain any decarbonation products. At these temperatures, permeability is sufficiently low to permit CO2 pore pressures to increase, thereby increasing local CO2 fugacity, which in turn strongly limits the decarbonation reaction. We note that, for non-pure calcite rocks, permeability might be sufficient to allow decarbonation reactions to occur. As such, variability in lithologies may slightly influence the efficiency of decarbonation reactions. We conclude that, in a closed system, the instability of Mt. Etna is related to high temperature induced ductile flow of basement limestone rather than chemical/mineralogical changes. This may have important implication for the stability of volcanoes within carbonate-rich basement, as carbonates become significantly weak at high temperatures, which may increase the risk of sector collapse. © 2015 Elsevier B.V

    Development of the Malocclusion Impact Questionnaire (MIQ) to measure the oral health-related quality of life of young people with malocclusion: part 2 - cross-sectional validation.

    Get PDF
    OBJECTIVE: To test the items, identified through qualitative inquiry that might form the basis of a new Malocclusion Impact Questionnaire (MIQ) to measure the oral health-related quality of life (OHQoL) of young people with malocclusion. METHODS: Piloting with 13 young people reduced the number of items from 37 to 28. Cross-sectional testing involved a convenience sample aged 10-16 years, attending the Orthodontic Department of the Charles Clifford Dental Hospital, Sheffield. The fit and function of the initial MIQ questions were examined using item response theory. RESULTS: 184 participants (113 females; 71 males) completed a questionnaire (response 85%), seven participants were excluded due to missing responses. The mean age of participants was 12·9 years (SD 1·4) and they had a wide range of malocclusions. The majority were White British (67·4%). Data from 47 participants were used to analyse test-retest reliability. Rasch analysis was undertaken, which further reduced the number of items in the questionnaire from 28 to 17. Unidimensionality of the scale was confirmed. The analysis also identified that the original 5-point response scale could be reduced to three points. The new measure demonstrated good criterion validity (r = 0·751; P < 0·001) and construct validity with the two global questions ('Overall bother' ρ = 0·733 and 'Life overall' ρ = 0·701). Internal consistency (Cronbach's alpha = 0·906) and test-retest reliability Intraclass correlation coefficient (ICC = 0·78; 95% CI 0·61-0·88) were also good. CONCLUSION: Cross-sectional testing has shown the new MIQ to be both valid and reliable. Further evaluation is required to confirm the generalisability as well as the ability of the new measure to detect change over time (responsiveness)
    • 

    corecore