22 research outputs found

    Use of Electronic Spreadsheets to Facilitate Critical Thinking in Quantitative Courses

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    Electronic spreadsheets such as Microsoft Excel or Lotus can make a valuable contribution in the quantitative courses such as accounting or engineering. These spreadsheets can facilitate critical thinking by eliminating the repetitive calculations associated with scenario analysis. Students can then focus on the applications of managerial decision making or engineering analysis, instead of being overwhelmed by recurring mathematical iterations. It is crucial that the faculty member demonstrate to importance of critical thinking in the quantitative courses

    A Continuance of Marginal Cost Methodology in Project Change Management

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    Change management is an inevitable part in the engineering management of engineering projects so effective change management is critical to determine if the proposed changes add economic value to the project. The marginal cost methodology is proposed to effectively manage change and to parse the changes only to those which add economic value. The marginal cost methodology is valuable in engineering decision making and also facilitates statistical analysis in trade studies for applications to future projects

    A Criteria-Based Approach to the Traveling Salesman Problem (TSP)

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    The “traveling salesman problem (TSP)” is a classic minimum cost network flow problem in mathematical programming and graph theory that can be formulated in multiple configurations. The fundamental question, however, is: “what is a cost”? The original “traveling salesman problem (TSP)” defines distance as the cost and the objective is to minimize distance traveled. This paper proposes other “cost” criteria to the original problem and also proposes a maximum revenue network flow as a variant to improve managerial decision-making. The proposed decision table methodology can be applied to problems that involve multiple locations or multiple tasks to complete

    Recommendations to Internal Auditors Regarding the Auditing and Attestation of Mathematical Programming Models

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    Mathematical programming planning models increase operational efficiency and minimize operating costs, but the underlying mathematics generally is complex. Combinatorial optimization is technically sophisticated which requires a strong quantitative background to successfully implement. Most internal auditors will not have the technical training to critically assess the underlying mathematics of mathematical programming planning models, but the internal auditor can still provide insight and attestation which can increase the efficiency of mathematical programming planning models

    Revealing the micromechanics driving cellular division: optical manipulation of force-bearing substructure in mitotic cells

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    During the anaphase stage of mitosis, a motility force transports genetic material in the form of chromosomes to the poles of the cell. Chromosome deformations during anaphase transport have largely been attributed to viscous drag force, however LaFountain et. al. found that a physical tether connects separating chromosome ends in crane-fly spermatocytes such that a backwards tethering force elongates the separating chromosomes. In the presented study laser microsurgery was used to deduce the mechanistic basis of chromosome elongation in rat-kangaroo cells. In half of tested chromosome pairs, laser microsurgery between separating chromosome ends reduced elongation by 7±3% suggesting a source of chromosome strain independent of viscous drag. When microsurgery was used to sever chromosomes during transport, kinetochore attached fragments continued poleward travel while half of end fragments traveled towards the opposite pole and the remaining fragments either did not move or segregated to the proper pole. Microsurgery directed between chromosome ends always ceased cross-polar fragment travel suggesting the laser severed a physical tether transferring force to the fragment. Optical trapping of fragments moving towards the opposite pole estimates an upper boundary on the tethering force of 1.5 pN

    Elastic ‘tethers’ connect separating anaphase chromosomes in a broad range of animal cells.

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    We describe the general occurrence in animal cells of elastic components ("tethers") that connect individual chromosomes moving to opposite poles during anaphase. Tethers, originally described in crane-fly spermatocytes, exert force on chromosome arms opposite to the direction the anaphase chromosomes move. We show that they exist in a broad range of animal cells. Thus tethers are previously unrecognised components of general mitotic mechanisms that exert force on chromosomes and they need to be accounted for in general models of mitosis in terms of forces on chromosomes and in terms of what their roles might be

    Trapped_Chromosome_Fragment.mp4

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    A tethered chromosome arm is severed during anaphase transport with laser scissors (cut path indicated by green/red lines). The fragment travels towards the opposite cell pole and after a brief moment an optical trap centered at the black crosshair (the red circle indicates when the trap is active) is placed over the moving fragment. The fragment travels to and remains at the trap rim nearest the opposing pole until late in anaphase transport

    Abnormal White Matter Integrity Related to Head Impact Exposure in a Season of High School Varsity Football

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    The aim of this study was to determine whether the cumulative effects of head impacts from a season of high school football produce magnetic resonance imaging (MRI) measureable changes in the brain in the absence of clinically diagnosed concussion. Players from a local high school football team were instrumented with the Head Impact Telemetry System (HITS™) during all practices and games. All players received pre- and postseason MRI, including diffusion tensor imaging (DTI). Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) was also conducted. Total impacts and risk-weighted cumulative exposure (RWE), including linear (RWE(Linear)), rotational (RWE(Rotational)), and combined components (RWE(CP)), were computed from the sensor data. Fractional, linear, planar, and spherical anisotropies (FA, C(L), C(P), and C(S), respectively), as well as mean diffusivity (MD), were used to determine total number of abnormal white matter voxels defined as 2 standard deviations above or below the group mean. Delta (post-preseason) ImPACT scores for each individual were computed and compared to the DTI measures using Spearman's rank correlation coefficient. None of the players analyzed experienced clinical concussion (N=24). Regression analysis revealed a statistically significant linear relationship between RWE(CP) and FA. Secondary analyses demonstrated additional statistically significant linear associations between RWE (RWE(CP) and RWE(Linear)) and all DTI measures. There was also a strong correlation between DTI measures and change in Verbal Memory subscore of the ImPACT. We demonstrate that a single season of football can produce brain MRI changes in the absence of clinical concussion. Similar brain MRI changes have been previously associated with mild traumatic brain injury
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