1,686 research outputs found
Using Peer Grading and Proofreading to Ratchet Student Expectations in Preparing Accounting Cases
Accounting educators struggle with ways to incorporate the development of critical thinking and communication skills into the curriculum. Case analysis is one tool for developing these skills. We examine whether students’ case analysis scores improve as a result of participation in peer grading and peer review. We find that students improve their ability to perform case analyses after both evaluating and being evaluated by student peers. Students initially experience an Expectation Ratcheting learning effect after evaluating the case of a peer. Subsequently, students experience an Enhanced Feedback learning effect from the comments and suggestions made by the peers who evaluated (proofread) their cases
Orchestration of renewable generation in low energy buildings and districts using energy storage and load shaping
There is increasing penetration of renewable generation in buildings and districts. There are challenges in making the effective use of this generation. The objective of the ORIGIN project (Orchestration of Renewable Integrated Generation In Neighborhoods) is to shape loads so that the fraction of energy consumed that is from local renewable generation is maximized, and energy imported from outside sources is minimized. This paper presents the overall approach taken in the ORIGIN project and explores building physics aspects of solar thermal storage system orchestration. The case study districts are briefly introduced and characteristics of their generation, buildings, districts and shiftable loads described. The orchestration approach taken in ORIGIN is then presented. At the core of the ORIGIN system is the orchestration algorithm which generates informational and control outputs to shape future loads to best meet the objectives. The model based approach used to quantify thermal and electrical load shifting opportunities for pre-charging, coasting or avoiding loads, while meeting thermal comfort and other demands, is described using a solar thermal storage system as an example. The future steps for the ORIGIN project; retrofit of the ORIGIN system into existing districts and potential for other future applications is briefly discussed
Performance of the Center-Of-Curvature Optical Assembly During Cryogenic Testing of the James Webb Space Telescope
The James Webb Space Telescope (JWST) primary mirror (PM) is 6.6 meters in diameter and consists of 18 hexagonal segments, each 1.5 meters point-to-point. Each segment has a 6 degree-of-freedom hexapod actuation system and a radius-of-curvature (ROC) actuation system. The full telescope was tested at its cryogenic operating temperature at Johnson Space Center (JSC) in 2017. This testing included center-of-curvature measurements of the PM wavefront error using the Center-of-Curvature Optical Assembly (COCOA), along with the Absolute Distance Meter Assembly (ADMA). The COCOA included an interferometer, a reflective null, an interferometer-null calibration system, coarse and fine alignment systems, and two displacement measuring interferometer systems. A multiple-wavelength interferometer was used to enable alignment and phasing of the PM segments. By combining measurements at two laser wavelengths, synthetic wavelengths up to 15 millimeters could be achieved, allowing mirror segments with millimeter-level piston errors to be phased to the nanometer level. The ADMA was used to measure and set the spacing between the PM and the focus of the COCOA null (i.e., the PM center-of-curvature) for determination of the ROC. This paper describes the COCOA, the PM test setup, the testing performed, the test results, and the performance of the COCOA in aligning & phasing the PM segments and measuring the final PM wavefront error
Cadmium accumulation and interactions with zinc, copper, and manganese, analysed by ICP-MS in a long-term Caco-2 TC7 cell model
The influence of long-term exposure to cadmium (Cd) on essential minerals was investigated using a Caco-2
TC7 cells and a multi-analytical tool: microwave digestion and inductively coupled plasma mass spectrometry.
Intracellular levels, effects on cadmium accumulation, distribution, and reference concentration
ranges of the following elements were determined: Na, Mg, Ca, Cr, Fe, Mn, Co, Ni, Cu, Zn, Mo, and Cd.
Results showed that Caco-2 TC7 cells incubated long-term with cadmium concentrations ranging from 0 to
10 lmol Cd/l for 5 weeks exhibited a significant increase in cadmium accumulation. Furthermore, this
accumulation was more marked in cells exposed long-term to cadmium compared with controls, and that
this exposure resulted in a significant accumulation of copper and zinc but not of the other elements
measured. Interactions of Cd with three elements: zinc, copper, and manganese were particularly studied.
Exposed to 30 lmol/l of the element, manganese showed the highest inhibition and copper the lowest on
cadmium intracellular accumulation but Zn, Cu, and Mn behave differently in terms of their mutual
competition with Cd. Indeed, increasing cadmium in the culture medium resulted in a gradual and significant
increase in the accumulation of zinc. There was a significant decrease in manganese from 5 lmol
Cd/l exposure, and no variation was observed with copper.
Abbreviation: AAS – Atomic absorption spectrometry; CRM– Certified reference material; PBS – Phosphate
buffered saline without calcium and magnesium; DMEM – Dubelcco’s modified Eagle’s medium
ERCC1 expression and RAD51B activity correlate with cell cycle response to platinum drug treatment not DNA repair
Background: The H69CIS200 and H69OX400 cell lines are novel models of low-level platinum-drug resistance. Resistance was not associated with increased cellular glutathione or decreased accumulation of platinum, rather the resistant cell lines have a cell cycle alteration allowing them to rapidly proliferate post drug treatment. Results: A decrease in ERCC1 protein expression and an increase in RAD51B foci activity was observed in association with the platinum induced cell cycle arrest but these changes did not correlate with resistance or altered DNA repair capacity. The H69 cells and resistant cell lines have a p53 mutation and consequently decrease expression of p21 in response to platinum drug treatment, promoting progression of the cell cycle instead of increasing p21 to maintain the arrest.
Conclusion: Decreased ERCC1 protein and increased RAD51B foci may in part be mediating the maintenance of the cell cycle arrest in the sensitive cells. Resistance in the H69CIS200 and H69OX400 cells may therefore involve the regulation of ERCC1 and RAD51B independent of their roles in DNA repair. The novel mechanism of platinum resistance in the H69CIS200 and H69OX400 cells demonstrates the multifactorial nature of platinum resistance which can occur independently of alterations in DNA repair capacity and changes in ERCC1
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