4,797 research outputs found

    Children at risk : their phonemic awareness development in holistic instruction

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    Includes bibliographical references (p. 17-19

    Explicit comprehension instruction : a review of research and a new conceptualization of instruction

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    Includes bibliographical references (p. 13-16)The work upon which this publication was based was supported in part by the Office of Educational Research and Improvement under cooperative agreement no. OEG 0087-C100

    The effect of background knowledge on young children's comprehension of explicit and implicit information

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    Bibliography: leaves 15-16Supported in part by the National Institute of Educatio

    Foreward

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    Natural and anthropogenic lead in sediments of the Rotorua lakes, New Zealand

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    Global atmospheric sources of lead have increased more than 100-fold over the past century as a result of deforestation, coal combustion, ore smelting and leaded petroleum. Lead compounds generally accumulate in depositional areas across the globe where, due to low solubility and relative freedom from microbial degradation, the history of their inputs is preserved. In lakes there is rapid deposition and often little bioturbation of lead, resulting in an excellent depositional history of changes in both natural and anthropogenic sources. The objective of this study was to use sediments from a regionally bounded set of lakes to provide an indication of the rates of environmental inputs of lead whilst taking into account differences of trophic state and lead exposure between lakes. Intact sediment gravity cores were collected from 13 Rotorua lakes in North Island of New Zealand between March 2006 and January 2007. Cores penetrated sediments to a depth of 16–30 cm and contained volcanic tephra from the 1886 AD Tarawera eruption. The upper depth of the Tarawera tephra enabled prescription of a date for the associated depth in the core (120 years). Each core showed a sub-surface peak in lead concentration above the Tarawera tephra which was contemporaneous with the peak use of lead alkyl as a petroleum additive in New Zealand. An 8 m piston core was taken in the largest of the lakes, Lake Rotorua, in March 2007. The lake is antipodal to the pre-industrial sources of atmospheric lead but still shows increasing lead concentrations from <2 up to 3.5 ÎŒg g−1 between the Whakatane eruption (5530 ± 60 cal. yr BP) and the Tarawera eruption. Peaks in lead concentration in Lake Rotorua are associated with volcanic tephras, but are small compared with those arising from recent anthropogenic-derived lead deposition. Our results show that diagenetic processes associated with iron, manganese and sulfate oxidation-reduction, and sulfide precipitation, act to smooth distributions of lead from anthropogenic sources in the lake sediments. The extent of this smoothing can be related to changes in sulfate availability and reduction in sulfide driven by differences in trophic status amongst the lakes. Greatest lead mobilisation occurs in mesotrophic lakes during seasonal anoxia as iron and manganese are released to the porewater, allowing upward migration of lead towards the sediment–water interface. This lead mobilisation can only occur if sulfides are not present. The sub-surface peak in lead concentrations in lake sediments ascribed to lead alkyl in petroleum persists despite the diagenetic processes acting to disperse lead within the sediments and into the overlying water

    Historical and contemporary perspectives on the sediments of Lake Rotorua

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    Lake Rotorua is probably the oldest continuously inundated lake in New Zealand, occupying a caldera formed by or closely associated with the eruption of the Mamaku ignimbrite and the collapse of the Rotorua caldera (Healy, 1975; Lowe and Green, 1991). The lake has undergone drastic changes in size and depth as a result of tectonics, volcanic activity and erosion. Since the Rotoehu eruption, (~60 kyr), the lake level has fluctuated between 120 m above present (280 m asl) and 10 m below present level. The modern lake covers an area of 79 km2 and has a mean depth of 10 m. Despite its long history of sedimentation, Lake Rotorua has an irregular bathymetry with features including faulted blocks, slumps, hydrothermal explosion craters, springs and large methane discharge pock marks

    Factors influencing multiple sclerosis disease-modifying treatment prescribing decisions in the United Kingdom: A qualitative interview study

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    Background The proportion of people with relapsing-remitting multiple sclerosis prescribed disease modifying treatments (DMTs) in the United Kingdom (UK) is considered low compared with other countries. There are differences in DMT prescription rates between UK nations (England, Wales, Scotland, Northern Ireland). Despite this, there has been little research into decision-making processes and prescribing practices. Objective To investigate views and experiences of neurologists prescribing DMTs and MS specialist nurses to identify factors influencing prescribing. Methods Semi-structured interviews with 18 consultant neurologists and 16 specialist nurses from diverse settings across the four UK nations. Data were analysed using thematic framework analysis. Results Prescribing practices are influenced by organisational prescribing “cultures”, informal “benchmarking” within peer networks, and prior experience with different DMTs. Health professionals differ in their perceptions of benefits and risks of DMTs and personal “thresholds” for discerning relapses and determining eligibility for DMTs. Prescribers in England felt most constrained by guidelines. Conclusion To achieve equity in access to DMTs for people with MS eligible for treatment, there is a need for public discussion acknowledging differences in health professionals’ interpretations of “relapses” and guidelines and perceptions of DMTs, variation in organisational prescribing “cultures”, and whether the prevailing culture sufficiently meets patients’ needs

    Demographics and cardiology, 1950–2050

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    Reading, Writing, and Thinking Like a Scientist

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