51 research outputs found

    A survey of employers of recent business graduates of Weymouth High School.

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    Thesis (Ed.M.)--Boston Universit

    A fabrication guide for planar silicon quantum dot heterostructures

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    We describe important considerations to create top-down fabricated planar quantum dots in silicon, often not discussed in detail in literature. The subtle interplay between intrinsic material properties, interfaces and fabrication processes plays a crucial role in the formation of electrostatically defined quantum dots. Processes such as oxidation, physical vapor deposition and atomic-layer deposition must be tailored in order to prevent unwanted side effects such as defects, disorder and dewetting. In two directly related manuscripts written in parallel we use techniques described in this work to create depletion-mode quantum dots in intrinsic silicon, and low-disorder silicon quantum dots defined with palladium gates. While we discuss three different planar gate structures, the general principles also apply to 0D and 1D systems, such as self-assembled islands and nanowires.Comment: Accepted for publication in Nanotechnology. 31 pages, 12 figure

    Transcriptional profiling of fibroblasts from patients with mutations in MCT8 and comparative analysis with the human brain transcriptome

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    Thyroid hormone (TH) is crucial for normal brain development. TH transporters control TH homeostasis in brain as evidenced by the complex endocrine and neurological phenotype of patients with mutations in monocarboxylate transporter 8 (MCT8). We investigated the mechanisms of disease by analyzing gene expression profiles in fibroblasts from patients with MCT8 mutations. Studying MCT8 and its transcriptional context in different comprehensive spatial and temporal human brain transcriptome data sets revealed distinct region-specific MCT8 expression. Furthermore, MCT8 demonstrated a clear age-dependent decrease, suggesting its importance in early brain development. Performing comparative transcriptome analysis, we linked the genes differentially expressed (DE) in patient fibroblasts to the human brain transcriptome. DE genes in patient fibroblasts were strongly over-represented among genes highly correlated with MCT8 expression in brain. Furthermore, using the same approach we identified which genes in the classical TH signaling pathway are affected in patients. Finally, we provide evidence that the TRα2 receptor variant is closely connected to MCT8. The present study provides amolecular basis for understanding which pathways are likely affected in the brains of patients with mutations in MCT8. Our data regarding a functional relationship between MCT8 and TRα2 suggest an unanticipated role for TRα2 in the (patho)physiology of TH signaling in the brain. This study demonstrates how genome-wide expression data from patient-derived non-neuronal tissue related to the human brain transcriptome may be successfully employed to improve our understanding of neurological disease

    Prevention of acute kidney injury and protection of renal function in the intensive care unit

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    Acute renal failure on the intensive care unit is associated with significant mortality and morbidity. To determine recommendations for the prevention of acute kidney injury (AKI), focusing on the role of potential preventative maneuvers including volume expansion, diuretics, use of inotropes, vasopressors/vasodilators, hormonal interventions, nutrition, and extracorporeal techniques. A systematic search of the literature was performed for studies using these potential protective agents in adult patients at risk for acute renal failure/kidney injury between 1966 and 2009. The following clinical conditions were considered: major surgery, critical illness, sepsis, shock, and use of potentially nephrotoxic drugs and radiocontrast media. Where possible the following endpoints were extracted: creatinine clearance, glomerular filtration rate, increase in serum creatinine, urine output, and markers of tubular injury. Clinical endpoints included the need for renal replacement therapy, length of stay, and mortality. Studies are graded according to the international Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) group system Several measures are recommended, though none carries grade 1A. We recommend prompt resuscitation of the circulation with special attention to providing adequate hydration whilst avoiding high-molecular-weight hydroxy-ethyl starch (HES) preparations, maintaining adequate blood pressure using vasopressors in vasodilatory shock. We suggest using vasopressors in vasodilatory hypotension, specific vasodilators under strict hemodynamic control, sodium bicarbonate for emergency procedures administering contrast media, and periprocedural hemofiltration in severe chronic renal insufficiency undergoing coronary intervention

    An in-service program on the use of the hand-held calculator for mathematics teachers in grades five through eight

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    The study was motivated by the lack of a formal in-service program for Newfoundland teachers on the use of the hand-held calculator in mathematics. -- The purpose of the study was to evaluate the effectiveness of an in-service model developed by the investigator, on the use of the hand-held calculator for mathematics teachers in grades five through eight. -- The sample consisted of 30 mathematics teachers in grades five through eight employed by the Port aux Basques Integrated School Board. The model was evaluated in terms of its effectiveness in changing the teachers’ attitudes toward the use of calculators in mathematics instruction, and in increasing the teachers’ understanding of the basic arithmetic operations on a calculator. -- To test the program’s effectiveness two null hypotheses were set up: -- 1. There is no significant change in teachers’ attitudes toward calculators as a result of the in-service program. -- 2. There is no significant change in calculator knowledge as a result of the in-service program. -- A needs assessment enabled the investigator to design the objectives of the program which attempted to change teachers’ attitude, to improve their understanding of the calculator, and to demonstrate how the calculator might be effectively integrated into mathematics instruction. The materials for the program were selected from the North Carolina In-Service Program developed by Immerzeel and Ockenga (1978). -- The pre-test scores for attitude and calculator knowledge obtained through a needs assessment were compared with the post-test scores obtained at the conclusion of the program. The scores were compared and analyzed using a dependent t-test. A t-value of 6.53 for attitude, and t-value of 9.71 for calculator knowledge were both significant at the 0.05 level, and resulted in a rejection of both null hypotheses. -- In addition to a significant positive change in attitude and calculator knowledge, the in-service participants rated all in-service sessions very highly, indicating that they perceived the program to have been a success. -- The fifth chapter outlines several recommendations suggesting some minor modifications to the model, which is recommended for use with other mathematics teachers

    New ages for human occupation and climatic change at Lake Mungo Australia

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    Australia’s oldest human remains, found at Lake Mungo, include the world’s oldest ritual ochre burial (Mungo III) and the first recorded cremation (Mungo I). Until now, the importance of these finds has been constrained by limited chronologies and palaeoenvironmental information. Mungo III, the source of the world’s oldest human mitochondrial DNA, has been variously estimated at 30 thousand years (kyr) old, 42–45 kyr old and 62 +/- 6 kyr old. while radiocarbon estimates placed theMungo I cremation near 20–26 kyr ago. Here we report a new series of 25 optical ages showing that both burials occurred at 40 +/- 2 kyr ago and that humans were present at Lake Mungo by 50–46 kyr ago, synchronously with, or soon after, initial occupation of northern and western Australia. Stratigraphic evidence indicates fluctuations between lake-full and drier conditions from 50 to 40 kyr ago, simultaneously with increased dust deposition, human arrival and continent-wide extinction of the megafauna. This was followed by sustained aridity between 40 and 30 kyr ago. This new chronology corrects previous estimates for human burials at this important site and provides a new picture of Homo sapiens adapting to deteriorating climate in the world’s driest inhabited continent

    New ages for human occupation and climatic change at Lake Mungo, Australia

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    © 2003 Nature Publishing Group, a division of Macmillan Publishers Limited.Australia's oldest human remains, found at Lake Mungo, include the world's oldest ritual ochre burial (Mungo III) and the first recorded cremation (Mungo I). Until now, the importance of these finds has been constrained by limited chronologies and palaeoenvironmental information. Mungo III, the source of the world's oldest human mitochondrial DNA, has been variously estimated at 30 thousand years (kyr) old, 42-45 kyr old and 62 +/- 6 kyr old, while radiocarbon estimates placed the Mungo I cremation near 20-26 kyr ago. Here we report a new series of 25 optical ages showing that both burials occurred at 40 +/- 2 kyr ago and that humans were present at Lake Mungo by 50-46 kyr ago, synchronously with, or soon after, initial occupation of northern and western Australia. Stratigraphic evidence indicates fluctuations between lake-full and drier conditions from 50 to 40 kyr ago, simultaneously with increased dust deposition, human arrival and continent-wide extinction of the megafauna. This was followed by sustained aridity between 40 and 30 kyr ago. This new chronology corrects previous estimates for human burials at this important site and provides a new picture of Homo sapiens adapting to deteriorating climate in the world's driest inhabited continent.James M. Bowler, Harvey Johnston, Jon M. Olley, John R. Prescott, Richard G. Roberts, Wilfred Shawcross and Nigel A. Spoone
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