5,519 research outputs found
An analysis of fifth-grade pupils' subject preferences in relation to their teachers' preferences.
Thesis (Ed.M.)--Boston Universit
Revisiting Educational Policies and Priorities in Commonwealth Small States
The article can be viewed at: http://www.cedol.org/wp-content/uploads/2012/02/Michael-Crossley-article.pd
Revisiting Educational Policies and Priorities in Commonwealth Small States
The article can be viewed at: http://www.cedol.org/wp-content/uploads/2012/02/Michael-Crossley-article.pd
Antecedent flow conditions and nitrate concentrations in the Mississippi River basin
The relationship between antecedent flow conditions and nitrate
concentrations was explored at eight sites in the 2.9 million square kilometers
(km<sup>2</sup>) Mississippi River basin, USA. Antecedent flow conditions were
quantified as the ratio between the mean daily flow of the previous year and
the mean daily flow from the period of record (Qratio), and the Qratio was
statistically related to nitrate anomalies (the unexplained variability in
nitrate concentration after filtering out season, long-term trend, and
contemporaneous flow effects) at each site. Nitrate anomaly and Qratio were
negatively related at three of the four major tributary sites and upstream
in the Mississippi River, indicating that when mean daily streamflow during
the previous year was lower than average, nitrate concentrations were higher
than expected. The strength of these relationships increased when data were
subdivided by contemporaneous flow conditions. Five of the eight sites had
significant negative relationships (<i>p</i> ≤ 0.05) at high or moderately
high contemporaneous flows, suggesting nitrate that accumulates in these
basins during a drought is flushed during subsequent high flows. At half of
the sites, when mean daily flow during the previous year was 50 percent
lower than average, nitrate concentration can be from 9 to 27 percent
higher than nitrate concentrations that follow a year with average mean
daily flow. Conversely, nitrate concentration can be from 8 to 21 percent
lower than expected when flow during the previous year was 50 percent higher
than average. Previously documented for small, relatively homogenous basins,
our results suggest that relationships between antecedent flows and nitrate
concentrations are also observable at a regional scale. Relationships were
not observed (using all contemporaneous flow data together) for basins
larger than 1 million km<sup>2</sup>, suggesting that above this limit the overall
size and diversity within these basins may necessitate the use of more
complicated statistical approaches or that there may be no discernible
basin-wide relationship with antecedent flow. The relationships between
nitrate concentration and Qratio identified in this study serve as the basis
for future studies that can better define specific hydrologic processes
occurring during and after a drought (or high flow period) which influence
nitrate concentration, such as the duration or magnitude of low flows, and
the timing of low and high flows
Interfacing GHz-bandwidth heralded single photons with a room-temperature Raman quantum memory
Photonics is a promising platform for quantum technologies. However, photon
sources and two-photon gates currently only operate probabilistically.
Large-scale photonic processing will therefore be impossible without a
multiplexing strategy to actively select successful events. High
time-bandwidth-product quantum memories - devices that store and retrieve
single photons on-demand - provide an efficient remedy via active
synchronisation. Here we interface a GHz-bandwidth heralded single-photon
source and a room-temperature Raman memory with a time-bandwidth product
exceeding 1000. We store heralded single photons and observe a clear influence
of the input photon statistics on the retrieved light, which agrees with our
theoretical model. The preservation of the stored field's statistics is limited
by four-wave-mixing noise, which we identify as the key remaining challenge in
the development of practical memories for scalable photonic information
processing
Learning from Commonwealth small states: educational policies and priorities beyond 2015
The article can be viewed at http://www.cedol.org/wp-content/uploads/2013/09/Learning-from-Commonwealth-Crossley-et-al.pd
HAWC2 and BeamDyn: Comparison Between Beam Structural Models for Aero-Servo-Elastic Frameworks
Molecular analysis of endocrine disruption in hornyhead turbot at wastewater outfalls in southern california using a second generation multi-species microarray.
Sentinel fish hornyhead turbot (Pleuronichthysverticalis) captured near wastewater outfalls are used for monitoring exposure to industrial and agricultural chemicals of ~ 20 million people living in coastal Southern California. Although analyses of hormones in blood and organ morphology and histology are useful for assessing contaminant exposure, there is a need for quantitative and sensitive molecular measurements, since contaminants of emerging concern are known to produce subtle effects. We developed a second generation multi-species microarray with expanded content and sensitivity to investigate endocrine disruption in turbot captured near wastewater outfalls in San Diego, Orange County and Los Angeles California. Analysis of expression of genes involved in hormone [e.g., estrogen, androgen, thyroid] responses and xenobiotic metabolism in turbot livers was correlated with a series of phenotypic end points. Molecular analyses of turbot livers uncovered altered expression of vitellogenin and zona pellucida protein, indicating exposure to one or more estrogenic chemicals, as well as, alterations in cytochrome P450 (CYP) 1A, CYP3A and glutathione S-transferase-α indicating induction of the detoxification response. Molecular responses indicative of exposure to endocrine disruptors were observed in field-caught hornyhead turbot captured in Southern California demonstrating the utility of molecular methods for monitoring environmental chemicals in wastewater outfalls. Moreover, this approach can be adapted to monitor other sites for contaminants of emerging concern in other fish species for which there are few available gene sequences
Perspective and priorities for improvement of parathyroid hormone (PTH) measurement – A view from the IFCC Working Group for PTH
Parathyroid hormone (PTH) measurement in serum or plasma is a necessary tool for the exploration of calcium/phosphate disorders, and is widely used as a surrogate marker to assess skeletal and mineral disorders associated with chronic kidney disease (CKD), referred to as CKD-bone mineral disorders (CKD-MBD). CKD currently affects >10% of the adult population in the United States and represents a major health issue worldwide. Disturbances in mineral metabolism and fractures in CKD patients are associated with increased morbidity and mortality. Appropriate identification and management of CKD-MBD is therefore critical to improving clinical outcome. Recent increases in understanding of the complex pathophysiology of CKD, which involves calcium, phosphate and magnesium balance, and is also influenced by vitamin D status and fibroblast growth factor (FGF)-23 production, should facilitate such improvement. Development of evidence-based recommendations about how best to use PTH is limited by considerable method-related variation in results, of up to 5-fold, as well as by lack of clarity about which PTH metabolites these methods recognise. This makes it difficult to compare PTH results from different studies and to develop common reference intervals and/or decision levels for treatment. The implications of these method-related differences for current clinical practice are reviewed here. Work being undertaken by the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) to improve the comparability of PTH measurements worldwide is also described
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