2,704 research outputs found

    New information on the Jurassic lepidosauromorph Marmoretta oxoniensis

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    The earliest known crown-group lepidosaurs are known from the Middle Triassic; however, their stem group is poorly sampled, with only a few representative fossils found. This is partly due to the small size and delicate bones of early stem-lepidosaurs (= non-lepidosaurian lepidosauromorphs), which make both preservation in the fossil record and subsequent discovery less likely. The Middle Jurassic lepidosauromorph Marmoretta oxoniensis is re-examined using high-resolution micro-computed tomography to reveal parts of the skull anatomy that were previously unknown. These include a squamosal, postorbital, more complete parietal, pterygoids, and an articulated posterior section of the mandible. Some differences between this and other Marmoretta specimens were identified as a result, such as the arrangement of palatal teeth and the shape of the parabasisphenoid. The status of Marmoretta as a stem-lepidosaur or stem-squamate has been debated. To evaluate this, we tested the phylogenetic position of Marmoretta by including our new data in an adapted phylogenetic character matrix. We recover Marmoretta as a stem-lepidosaur and sister to Fraxinisaura rozynekae. Our findings support the hypothesis that both taxa belonged to a clade of non-lepidosaurian lepidosauromorphs that co-existed with lepidosaurs into the Middle Jurassic

    A reassessment of the enigmatic diapsid Paliguana whitei and the early history of Lepidosauromorpha

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    Lepidosaurs include lizards, snakes, amphisbaenians and the tuatara, comprising a highly speciose evolutionary radiation with widely varying anatomical traits. Their stem-lineage originated by the late middle Permian 259 million years ago, but its early fossil record is poorly documented, obscuring the origins of key anatomical and functional traits of the group. Paliguana whitei, from the Early Triassic of South Africa, is an enigmatic fossil species with the potential to provide information on this. However, its anatomy and phylogenetic affinities remain highly uncertain, and have been debated since its discovery more than 100 years ago. We present microtomographic three-dimensional imaging of the cranial anatomy of P. whitei that clarifies these uncertainties, providing strong evidence for lepidosauromorph affinities based on the structure of the temporal region and the implantation of marginal dentition. Phylogenetic analysis including these new data recovers Paliguana as the earliest known stem-lepidosaur, within a long-lived group of early diverging lepidosauromorphs that persisted to at least the Middle Jurassic. Our results provide insights into cranial evolution on the lepidosaur stem-lineage, confirming that characteristics of pleurodont dental implantation evolved early on the lepidosaur stem-lineage. By contrast, key functional traits related to hearing (quadrate conch) and feeding (streptostyly) evolved later in the lepidosaur crown-group

    Unexplained mortalities of hatchery-reared, juvenile oysters, Crassostrea virginica (Gmelin)

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    Survival. growth and pathology of juvenile oysters. Crassostrea virginica. in off-bottom culture at Oyster Bay and Fishers Island, New York, were monitored during the summer of 1991 to document and help explain the episodic mass mortalities of cultured seed oysters that have occurred in the northeastern USA over the past several years. Al Oyster Bay. where the more detailed study was conducted. 54 to 7So/o losses affected several 1991 cohorts at mean shell heights ranging from IS to 24 mm, within 3 to 6V, weeks of transfer from the hatchery to growout trays. Mortalities occurred in July and August, at temperatures between 22 and 25°C, and were reduced significantly at low stocking densiucs. Deaths were associated with reduced tissue and shell growth. reduced condition index, mantle retraction, the deposition of an abnom1al conchiolin layer on the inner shell, and lesions of the mantle surface. No obvious pathogen was identified in soft tissues or shells by light or electron microscopy. The pathology suggested that a LOitin-producing agent of bacterial or microalgal origin. or chemical contaminant. caused mantle retraction and secretion of anomalous conchiolin as a defense mechanism. Two potential agents were recognized. Bacteria were found in mantle lesions and within the abnormal conchiolin sheet, but not consistently and with \u3c30% prevalence; il is not clear whether these were primary or secondary invaders. Blooms of a large dinoflagellate, Gymnmodium sanguineum. occurred at peak densities of 5 x I 05 cells 1- 1 at the time of initial oyster mortalities. although the species is not known to be toxic to bivalves. Follow up studies are planned to identify the etiological agent and culture methods that minimize losse

    Perkinsus marinus tissue distribution and seasonal variation in oysters Crassostrea virginica from Florida, Virginia and New York

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    Perkinsus marinus infection intensity was measured in eastern oysters Crassostrea virginica collected in October and December 1993, and March, May, and July 1994 from 3 U.S. sites: Apalachicola Bay (FL), Chesapeake Bay (VA), and Oyster Bay (Mr\u27). Gill, mantle, digestive gland. adductor muscle, hemolymph, and remaining tissue (including gonadal material and rectum) were dissected from 20 oysters from each site at each collection time. Samples were separately diagnosed for P. marin us infections by incubation in Ray\u27s Fluid Thioglycollate Medium (RFTM) and subsequent microscopic quantification of purified enlarged hypnospores. At all sampling times and sites, average P. marinus infection intensity (g wet wt tissue(-1) or ml hemolymph(-1)) was lowest in hemolymph samples, and generally highest in the digestive gland. Perkinsus marinus prevalence was 100% at both FL and NY sites for each of the 5 collection times, and, for the VA site, was less than 100% in only 1 month (May 1994). Seasonal intensity patterns and mean total body burdens differed among the sites. Average body burden was highest in VA during October and progressively declined to a minimum in May. This decline was probably due to mortality of heavily infected oysters and diminution of parasite activity associated with colder temperatures and reduced salinities. Intensities varied little during the months of October and December at both the FL and NY sites. Minimum average intensities were observed in March in FL oysters and May in NY oysters. Relatively high P. marinus infection levels that persisted throughout the winter in NY oysters compared with VA oysters could reflect constant high salinity in Long Island Sound which favors parasite activity, and also rapid decline in temperature in the fall that may have prevented epizootic oyster mortalities

    Investigating The Life Cycle Of Haplosporidium nelsoni (MSX)

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    Attempts to decipher the life cycle of Haplosporidium nelsoni began almost immediately after it was identified as the pathogen causing MSX disease in eastern oysters, Crassostrea virginica. But transmission experiments failed and the spore stage, characteristic of haplosporidans, was extremely rare. Researchers concluded that another host was involved: an intermediate host in which part of the life cycle was produced, or-if the oyster was an accidental host-an alternate host that produces infective elements. A later finding that spores were found more often in spat (\u3c 1 y old) than in adults revived the idea of direct transmission between oysters. The new findings and the availability of molecular diagnostics led us to revive life cycle investigations. Over several years, oyster spat were examined for spores and searched for H. nelsoni in potential non-oyster hosts using both histological and polymerase chain reaction (PCR) methodologies. Although spores occurred in a high proportion of spat with advanced infections, it was concluded that they were unlikely to be a principal source of infective elements because naive oysters used as sentinels to assess infection pressure became highly infected even after native oysters developed resistance, and infected spat could no longer be found. A histological survey of zooplankton and small bivalves in Delaware Bay found few recognizable parasites and nothing resembling a haplosporidan. A subsequent PCR study of water, sediment, and macro-invertebrates from Chesapeake, Delaware, and Oyster bays resulted in many positive samples, but in situ hybridization failed to identify any recognizable structures. PCR analysis of potential intermediate hosts for other molluscan pathogens has also resulted in many species yielding positive results but required in situ hybridization to verify infections. It is suggested that any future search for a nonoyster host of H. nelsoni be conducted in a relatively confined system and/or target specific phyla, strategies that have been successful in other life cycle studies. It is noted that candidate phyla could include those known to host haplosporidans and species whose abundance or distribution may have changed in concert with outbreaks of MSX disease in the northeastern United States in recent years

    Enabling local public health adaptation to climate change

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    Local public health authorities often lack the capacity to adapt to climate change, despite being on the ‘front lines’ of climate impacts. Upper-level governments are well positioned to create an enabling environment for adaptation and build local public health authorities' capacity, yet adaptation literature has not specified how upper-level governments can build local-level adaptive capacity. In this paper we examine how federal and regional governments can contribute to enabling and supporting public health adaptation to climate change at the local level in federal systems. We outline the local level's self-assessed adaptive capacity for public health adaptation in Canadian and German comparative case studies, in terms of funding, knowledge and skills, organizations, and prioritization, drawing upon 30 semi-structured interviews. Based on interviewees' recommendations and complemented by scientific literature, we develop a set of practical measures that could enable or support local-level public health adaptation. We find that adaptive capacity varies widely between local public health authorities, but most report having insufficient funding and staff for adaptation activities. We propose 10 specific measures upper-level governments can take to build local public health authorities' capacity for adaptation, under the interrelated target areas of: building financial capital; developing and disseminating usable knowledge; collaborating and coordinating for shared knowledge; and claiming leadership. Federal and regional governments have an important role to play in enabling local-level public health adaptation, and have many instruments available to them to fulfill that role. Selecting and implementing measures to enable local public health authorities' adaptive capacity will require tailoring to, and consideration, of the local context and needs

    Participatory Action Research on School Culture and Student Mental Health: A Study Protocol

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    Background: Young people spend a large proportion of their time in school, which presents both risk and protective factors for their mental health. A supportive school culture can promote and protect good mental health by creating experiences of safety and belonging amongst staff and students. In this qualitative study, we seek to explore whether a participatory action research (PAR) approach is an effective way to promote and improve student mental health. Methods: Participatory action research is an approach in which people collaboratively research their own experience: the researched communities become co-researchers of their own experiences in a specific context. We will work with four secondary schools in the UK to develop PAR projects. In each school, a group of 2–4 staff and 6–8 students will work together to develop a shared understanding of their school culture and to introduce activities or changes to make the culture more supportive of student mental health. We will evaluate the effectiveness of the PAR approach through i) a review of school documents pertaining to mental health (e.g., policies and Ofsted reports), ii) interviews with staff members ( n = 40), parents ( n = 8) and students ( n = 24–40) before and after the PAR intervention, iii) observations and reports of the PAR group meetings and iv) interviews with members of the PAR groups after the PAR intervention. Discussion: We anticipate that our research findings will advance knowledge on effective methods to develop a positive school culture that will contribute to the improvement of young people’s mental health and well-being. We will seek to identify the mechanisms through which school culture can have a positive impact on mental health and develop a logic model and a school culture toolkit that can be utilised as a resource to inform public health interventions to promote mental health in a range of educational settings.National Institute for Health Research (NIHR) School for Public Health Research (Grant Reference Number PD–SPH–2015)

    What does the Paris Agreement mean for adaptation?

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    The Paris Agreement takes a significant step forward in strengthening the adaptation pillar of global climate policy. By widening the normative framing around adaptation, calling for stronger adaptation commitments from states, being explicit about the multilevel nature of adaptation governance, and outlining stronger transparency mechanisms for assessing adaptation progress, the Agreement is a milestone in ongoing efforts to make adaptation an equal priority with mitigation. Significant work remains to be done, however, to clarify how the long-term goal for adaptation set out in Article 7 will be meaningfully realized. The challenge for Parties in implementing the Paris Agreement will be to establish credible commitments from state and non-state actors with regard to adaptation planning, implementation, and financing

    Chemotherapy vs supportive care alone for relapsed gastric, gastroesophageal junction, and oesophageal adenocarcinoma: a meta-analysis of patient-level data.

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    BACKGROUND: Second-line chemotherapy treatment of patients with relapsed gastric and oesophageal cancers in comparison with supportive care (SC) alone has been supported by recent phase 3 clinical trials, but a meta-analysis of patient-level data is lacking. METHODS: We searched Medline, the Cochrane Central Register of Controlled Trials (CENTRAL), and the Web of Science for phase 3 clinical trials that compared second-line chemotherapy with SC alone for gastric and oesophageal cancers. A meta-analysis of the comprehensive patient-level data from the three identified trials was performed. RESULTS: A total of 410 patients with gastric (n=301), gastroesophageal junction (n=76), or oesophageal (n=33) adenocarcinoma were identified. In all, 154 patients received single-agent docetaxel and 84 patients received single-agent irinotecan, each with SC. SC alone was given to 172 patients. Chemotherapy significantly reduced the risk of death (hazard ratio (HR)=0.63, 95% confidence interval (CI)=0.51-0.77, P<0.0001). This effect was observed for treatment with docetaxel (HR=0.71, 95% CI=0.56-0.89, P=0.003) and irinotecan (HR=0.49, 95% CI=0.36-0.67, P<0.001). Overall survival (OS) benefit was greatest for patients who progressed 3-6 months following first-line chemotherapy (HR=0.39, 95% CI=0.26-0.59, P<0.0001). Performance status (PS) 0-1 compared with PS 2 (HR=0.66, 95% CI=0.46-0.94, P=0.02), locally advanced disease compared with metastatic disease (HR=0.41, 95% CI=0.25-0.67, P=0.0004) and older age (HR=0.94 per 5 years, 95% CI=0.90-0.99, P=0.01) were significant predictors of improved OS. Progression of disease during first-line treatment (HR=1.24, 95% CI=0.96-1.59) or within the first 3 months of completion of first-line treatment (HR=1.42, 95% CI=1.09-1.83) were predictors of an increased risk of death compared with progression between 3 and 6 months (P=0.03). Health-related quality of life outcomes were reported in only one of the three trials, precluding meta-analysis of these parameters. CONCLUSIONS: This meta-analysis of patient-level data confirms that second-line chemotherapy treatment results in significantly better OS compared with SC alone in patients with platinum and fluoropyrimidine refractory gastric and oesphageal adenocarcinoma. Health-related quality of life outcomes should be included in future trials in this setting.TJ and CC were supported by the Wellcome Trust Translational Medicine and Therapeutics programme and the National Institute for Health Research.This is the final version of the article. It first appeared from Nature Publishing Group via http://dx.doi.org/10.1038/bjc.2015.45

    Randomized controlled trial of a good practice approach to treatment of childhood obesity in Malaysia: Malaysian childhood obesity treatment trial (MASCOT)

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    Context. Few randomized controlled trials (RCTs) of interventions for the treatment of childhood obesity have taken place outside the Western world. Aim. To test whether a good practice intervention for the treatment of childhood obesity would have a greater impact on weight status and other outcomes than a control condition in Kuala Lumpur, Malaysia. Methods. Assessor-blinded RCT of a treatment intervention in 107 obese 7- to 11-year olds. The intervention was relatively low intensity (8 hours contact over 26 weeks, group based), aiming to change child sedentary behavior, physical activity, and diet using behavior change counselling. Outcomes were measured at baseline and six months after the start of the intervention. Primary outcome was BMI z-score, other outcomes were weight change, health-related quality of life (Peds QL), objectively measured physical activity and sedentary behavior (Actigraph accelerometry over 5 days). Results. The intervention had no significant effect on BMI z score relative to control. Weight gain was reduced significantly in the intervention group compared to the control group (+1.5 kg vs. +3.5 kg, respectively, t-test p &lt; 0.01). Changes in health-related quality of life and objectively measured physical activity and sedentary behavior favored the intervention group. Conclusions. Treatment was associated with reduced rate of weight gain, and improvements in physical activity and quality of life. More substantial benefits may require longer term and more intensive interventions which aim for more substantive lifestyle changes
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