96 research outputs found

    A Probable Approx. 2400 Year Solar Quasi-cycle in Atmospheric Delta C-14

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    A 2200 to 2600 year quasi-periodicity is present in atmospheric delta C-14 records after removal of long-term trends due to the geomagnetic dipole amplitude variation. This periodicity consists of both a long-term variation of the mean and a superposed, approximately recurring pattern of century-scale variations. The strongest of these latter variations occur near maxima of the approx. 2400 year delta C-14 cycles. The residual record can be modeled to first order as an amplitude modulation of a century-scale periodic forcing function by a approx. 2400 year periodic forcing function. During the last millennium, the largest century-scale variations (occurring near the most recent 2400 year delta C-14 maximum) are known to be mainly a consequence of the pronounced Maunder, Sporer, and Wolf solar activity minima, as verified by independent proxy solar activity records. Therefore, during this period, amplitude modulation has been occurring primarily in the sun and not in the terrestrial radiocarbon system. It is therefore inferred that the approx. 2400 year forcing function is mainly solar although some secondary terrestrial feedback into the delta C-14 record is likely. This conclusion has implications for the predictability of future pronounced solar activity minima and for the interpretation of certain minor Holocene climatic variations

    A Mechanism Involving Solar Ultraviolet Variations for Modulating the Interannual Climatology of the Middle Atmosphere

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    In years of low solar activity, free traveling wave modes in the upper stratosphere are dominated by atmospheric normal modes such as the 16-day wave. However, within a 4-year interval centered on the 1980 to 1981 solar maximum, cross-spectral analyses of zonal mean satellite temperature data versus the solar UV flux demonstrate significant power near 27 and 13 days, providing indirect evidence that short-term UV variations were capable of exciting traveling planetary-scale waves in the upper stratosphere. Previous theoretical and observational work has indicated that interference between traveling waves and stationary waves forced from below (and the resulting oscillating latitudinal heat transports) plays a likely role in the initiation of stratospheric warmings. Researchers therefore hypothesize that the initiation of a major stratospheric warming in the upper stratosphere and lower mesosphere may depend to some extent on the amplitude of longer-period 27-day traveling waves in the upper stratosphere. This would represent a new mechanism for solar UV effects on stratospheric climatology that may be relevant to the interpretation of some recent long-term correlative results

    Challenges in Transitioning From Clinician to Educator for Occupational Therapy Assistant Program Faculty Members

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    There is a transitional process that occurs when an occupational therapy (OT) practitioner assumes the role of an educator. Various challenges have been reported, though few directly address occupational therapy assistant (OTA) education. This study aimed to identify challenges faced by OT practitioners when they transition from working in a clinical setting to working as OTA faculty members. A 29-item online survey was developed covering three key areas of new OTA faculty members’ responsibilities: a) Learning the Educator Role, b) Curriculum and Class Development, and c) Interacting with Students. The survey was distributed through the American Occupational Therapy Association Program Directors’ and Academic Fieldwork Coordinators’ listservs, the Education Special Interest Section listserv and direct email to faculty members. Two hundred twenty-three participants completed the survey. Eight items were rated by 60% of participants as “Moderately” or “Very” challenging. Six of these items were in the category of Curriculum and Class Development, and two items were in the category of Learning the Educator Role. Interacting with Students was a relative area of comfort and strength. No significant relationships were found between the level of challenge experienced by OT practitioners transitioning to OTA educators and the demographic factors that were examined. Content analysis of open-ended survey questions yielded additional themes in each of the three categories that offer deeper insights into specific challenges. Collectively, results highlight areas where support and professional development can enhance successful clinician to OTA educator transitions

    Radiocarbon record of solar variability and Holocene climatic change in coastal southern California

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    EXTRACT (SEE PDF FOR FULL ABSTRACT): Pollen analysis and 5 radiocarbon dates for a 687-cm core provide a detailed chronology of environmental change for San Joaquin Marsh at the head of Newport Bay, Orange County, California. Sediment deposition kept pace with sea level rise during the mid-Holocene, but after 4500 years BP, sea water regularly reached the coring site, and salt marsh was the local vegetation. Brief periods of dominance by fresh-water vegetation 3800, 2800, 2300 and after 560 years BP correlate global cooling events and (except the 3800-year BP event) with carbon-14 production anomalies. The coincidence of climate change and carbon-14 anomalies support a causal connection with solar variability, but regardless of the causal mechanism(s) the delta-carbon-14 curves provide a chronology for global, high-frequency climatic change comparable to that of Milankovitch cyclicity for longer time scales

    Graphomotor skills in children with prenatal alcohol exposure and fetal alcohol spectrum disorder: A population-based study in remote Australia

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    Background/aim: Few studies have examined graphomotor skills in children with prenatal alcohol exposure (PAE) or fetal alcohol spectrum disorder (FASD). Methods: Graphomotor skills were assessed in 108 predominantly Australian Aboriginal children aged 7.5-9.6 years in remote Western Australia using clinical observations (pencil grasp; writing pressure) and standardised assessment tools (the Evaluation Tool of Children's Handwriting; and the Miller Function and Participation Scales - The Draw-a-Kid Game). Skills were compared between children (i) without PAE, (ii) PAE but not FASD and (iii) FASD. Results: Most children used a transitional pencil grasp and exerted heavy handwriting pressure (83.3% and 30.6% of the cohort). The percentage of letters (M = 62.9%) and words (M = 73.3%) written legibly was low. Children with FASD were more likely than children without PAE to use a cross-thumb grasp (P = 0.027), apply heavy writing pressure (P = 0.036), be unable to write a sentence (P = 0.041) and show poorer word legibility (P = 0.041). There were no significant differences between groups for drawing outcomes, although some children with FASD drew pictures that appeared delayed for their age. There were no significant differences between children without PAE and those with PAE but who were not diagnosed with FASD. Conclusions: Overall, graphomotor skills were poor in this cohort, but children with FASD performed significantly worse than children without PAE. Findings suggest the need for improved occupational therapy services for children in remote regions and evaluation of graphomotor skills in children with PAE. © 2016 Occupational Therapy Australia

    Functional magnetic resonance imaging outcomes from a comprehensive magnetic resonance study of children with fetal alcohol spectrum disorders

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    A comprehensive neuropsychological/psychiatric, MR imaging, (MRI), MR spectroscopy (MRS), and functional MRI (fMRI) assessment was administered to children with fetal alcohol spectrum disorders (FASD) to determine if global and/or focal abnormalities could be identified, and distinguish diagnostic subclassifications across the spectrum. The four study groups included: 1. FAS/Partial FAS; 2. Static Encephalopathy/Alcohol Exposed (SE/AE); 3. Neurobehavioral Disorder/Alcohol Exposed (ND/AE); and 4. healthy peers with no prenatal alcohol exposure. fMRI outcomes are reported here. The neuropsychological/psychiatric, MRI, and MRS outcomes are reported separately. fMRI was used to assess activation in seven brain regions during performance of N-back working memory tasks. Children across the full spectrum of FASD exhibited significant working memory deficits and altered activation patterns in brain regions that are known to be involved in working memory. These results demonstrate the potential research and diagnostic value of this non-invasive MR tool in the field of FASD

    tafazzin gene mutations are uncommon causes of dilated cardiomyopathy in adults

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    Barth syndrome is an X-linked genetic condition featuring neutropenia, skeletal myopathy, and dilated cardiomyopathy in boys due to tafazzin (TAZ) mutations. Pure dilated cardiomyopathy without other features of Barth syndrome may also result from TAZ mutations and survival into adulthood has been described. Although TAZ testing is routinely included in dilated cardiomyopathy panels in adults, the prevalence of TAZ mutations in the adult population, including women who may be at risk to develop later onset disease due to TAZ mutations, has not been measured. We screened 292 families with dilated cardiomyopathy (209 male and 83 female probands) for TAZ mutations using denaturing high-performance liquid chromatography and sequence analysis. Putative mutations were evaluated based on standard criteria including screening available relatives and healthy controls and for effects on splicing efficiency in the case of one intronic variant. Two variants suspicious for being pathogenic were found in two unrelated families (c.387T>C, Phe128Ser and c.507C>T, Leu169Leu). The Phe128Ser variant had been previously reported as a pathogenic mutation; however we determined that this variant is instead a rare polymorphism restricted to African Americans. The Leu169Leu variant was detected in a male patient and altered RNA processing in our minigene assay supporting a pathogenic role. No mutations in female subjects were detected. Tafazzin mutations were rare in our population of adults with dilated cardiomyopathy and none were found in females. Our findings indicate that genetic testing for tafazzin should not be routinely performed in dilated cardiomyopathy as suggested by current guidelines. Furthermore, the Phe128Ser variant is not pathogenic, but likely represents a benign polymorphism in persons of African American ancestry

    Reconstructing 800 years of summer temperatures in Scotland from tree rings

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    We thank The Carnegie Trust for the Universities of Scotland for providing funding for Miloš Rydval’s PhD. The Scottish pine network expansion has been an ongoing task since 2007 and funding must be acknowledged to the following projects: EU project ‘Millennium’ (017008-2), Leverhulme Trust project ‘RELiC: Reconstructing 8000 years of Environmental and Landscape change in the Cairngorms (F/00 268/BG)’ and the NERC project ‘SCOT2K: Reconstructing 2000 years of Scottish climate from tree rings (NE/K003097/1)’.This study presents a summer temperature reconstruction using Scots pine tree-ring chronologies for Scotland allowing the placement of current regional temperature changes in a longer-term context. ‘Living-tree’ chronologies were extended using ’subfossil’ samples extracted from nearshore lake sediments resulting in a composite chronology > 800 years in length. The North Cairngorms (NCAIRN) reconstruction was developed from a set of composite blue intensity high-pass and ring-width low-pass chronologies with a range of detrending and disturbance correction procedures. Calibration against July-August mean temperature explains 56.4% of the instrumental data variance over 1866-2009 and is well verified. Spatial correlations reveal strong coherence with temperatures over the British Isles, parts of western Europe, southern Scandinavia and northern parts of the Iberian Peninsula. NCAIRN suggests that the recent summer-time warming in Scotland is likely not unique when compared to multi-decadal warm periods observed in the 1300s, 1500s, and 1730s, although trends before the mid-16th century should be interpreted with some caution due to greater uncertainty. Prominent cold periods were identified from the 16th century until the early 1800s – agreeing with the so-called Little Ice Age observed in other tree-ring reconstructions from Europe - with the 1690s identified as the coldest decade in the record. The reconstruction shows a significant cooling response one year following volcanic eruptions although this result is sensitive to the datasets used to identify such events. In fact, the extreme cold (and warm) years observed in NCAIRN appear more related to internal forcing of the summer North Atlantic Oscillation.Publisher PDFPeer reviewe

    Exploring service providers’ perspectives on the prevention and management of fetal alcohol spectrum disorders in South Africa: a qualitative study

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    BACKGROUND: Fetal alcohol spectrum disorder (FASD) is among the leading causes of developmental and intellectual disabilities in individuals. Although efforts are being made toward the prevention and management of FASD in South Africa, the prevalence remains high. The sustained high prevalence could be attributed to several factors, including the lack of policy for a coordinated effort to prevent, diagnose and manage FASD nationally. In this study, our aim was to explore the perspectives of service providers (health and allied professionals, teachers, social workers) on the prevention and management of FASD towards developing a guideline to inform policy. METHOD: Guided by the exploratory qualitative research design, we purposively sampled relevant service providers in the field of FASD prevention and management for focus group discussions. Nine of these discussions were conducted with to eight participants per discussion session. The discussants were asked various questions on the current and required interventions and practices for the prevention and management of FASD. Following the Framework Method, data were transcribed verbatim and analysed using the thematic content analysis approach. RESULTS: Our findings show that aspects of the prevention and management of alcohol-related conditions are present in various policies. However, there is no clear focus on coordinated, multi-sectoral efforts for a more comprehensive approach to the prevention and management of FASD. The participants recognized the need for specific requirements on broad-based preventive awareness programs, training and support for parents and caregivers, inclusive education in mainstream schools and training of relevant professionals. CONCLUSION: Comprehensive and coordinated prevention and management programs guided by a specific policy could improve the prevention and management of FASD. Policy formulation demonstrates commitment from the government, highlights the importance of the condition, and elaborates on context-specific prevention and management protocols.IS
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