24 research outputs found
The first occurrence of a toxodont (Mammalia, Notoungulata) in the United States
This is the publisher's version, also available electronically from http://www.tandfonline.com/doi/abs/10.1080/02724634.2012.711405#.U1qJK4UvDGJ.Toxodonts were a group of large-sized notoungulates of South American origin. They were diverse and widespread in South America in deposits ranging in age from late Oligocene to late Pleistocene. Sparse remains have been found from the Pleistocene of isolated regions of Central America. All of the Central American specimens have been referred to the genus Mixotoxodon (Van Frank, 1950). They were not previously known north of the southern Mexican states of Michoacan and Veracruz, except for an unconfirmed report of an occurrence in Tamaulipas (Arroyo-Cabrales et al., 2010). Here we report the occurrence of a single toxodont tooth, a left upper third molar, from late Pleistocene deposits in Harris County, Texas (30◦N). This is the first record of toxodonts, or any notoungulate, in the United States and extends the geographic range of this group 1600 km north of their previously known localities at Hihuitlán, Michoacan (18◦52' 3"0 N, 103◦24' 14 "W) and La Estribera, Veracruz (18◦07 '01.27" N, 94◦53 '15.59W) (Polaco et al., 2004) to latitude 30◦N
Advanced practice for children and young people: A systematic review with narrative summary
AimTo critically appraise and synthesise the current evidence related to the advanced practice nurse (APN) in the children and young people's healthcare setting.BackgroundA complex landscape of demand and change has influenced the healthcare delivery for children and young people. In the United Kingdom and internationally, governments have endorsed the need for workforce innovation with APN roles introduced to counter these challenges. However, little is known about the impact of these initiatives in the context of children and young people's health care.DesignSystematic review and narrative summary.Data sourcesCINAHL, MEDLINE, DARE, PubMed, Prospero and Cochrane Database of Systematic Reviews were searched for studies published in English language from July 1998 to 2018. Studies were selected based on key search terms and eligibility criteria.Review methodsThe selected studies were appraised using the Effective Public Health Practice Project for quantitative studies. An adapted version of the JBI data extraction tool for experimental/observational studies was used to extract the relevant key findings. This was conducted independently by two researchers.ResultsNine studies were included in the review. The review demonstrated roles were comparable in their clinical practice to medics yet offered higher levels of patient satisfaction, role modelling for staff and led practice initiatives to improve health literacy.ConclusionThis review demonstrates that APN roles in children and young people's health care provide clinical, organizational and professional benefits, with added value to organizations and patients, acting as role models and educators.ImpactThe findings from this review indicate further research is required to ascertain contextual issues that may influence the implementation of APNs. This research will impact APNs working with children and young people. Equally, it supports the evidence base for service commissioners outlining areas for future research
Synthesis of guanosine tetra- and pentaphosphates by the obligately anaerobic bacterium Bacteroides thetaiotaomicron in response to molecular oxygen
Functional Linkages for the Pace of Life, Life-history, and Environment in Birds
For vertebrates, body mass underlies much of the variation in metabolism, but among animals of the same body mass, metabolism varies six-fold. Understanding how natural selection can influence variation in metabolism remains a central focus of Physiological Ecologists. Life-history theory postulates that many physiological traits, such as metabolism, may be understood in terms of key maturational and reproductive characteristics over an organism’s life-span. Although it is widely acknowledged that physiological processes serve as a foundation for life-history trade-offs, the physiological mechanisms that underlie the diversification of life-histories remain elusive. Data show that tropical birds have a reduced basal metabolism (BMR), field metabolic rate, and peak metabolic rate compared with temperate counterparts, results consistent with the idea that a low mortality, and therefore increased longevity, and low productivity is associated with low mass-specific metabolic rate. Mass-adjusted BMR of tropical and temperate birds was associated with survival rate, in accordance with the view that animals with a slow pace of life tend to have increased life spans. To understand the mechanisms responsible for a reduced rate of metabolism in tropical birds compared with temperate species, we summarized an unpublished study, based on data from the literature, on organ masses for both groups. Tropical birds had smaller hearts, kidneys, livers, and pectoral muscles than did temperate species of the same body size, but they had a relatively larger skeletal mass. Direct measurements of organ masses for tropical and temperate birds showed that the heart, kidneys, and lungs were significantly smaller in tropical birds, although sample sizes were small. Also from an ongoing study, we summarized results to date on connections between whole-organism metabolism in tropical and temperate birds and attributes of their dermal fibroblasts grown in cell culture. Cells derived from tropical birds had a slower rate of growth, consistent with the hypothesis that these cells have a slower metabolism. We found that dermal fibroblasts from tropical birds resisted chemical agents that induce oxidative and non-oxidative stress better than do cells from temperate species, consistent with the hypothesis that birds that live longer invest more in self-maintenance such as antioxidant properties of cells