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Search Results: 1 - 10 of 406077 matches for " Sarah M. McMullen "
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Partial Ventilatory Support Modalities in Acute Lung Injury and Acute Respiratory Distress Syndrome—A Systematic Review
Sarah M. McMullen,Maureen Meade,Louise Rose,Karen Burns,Sangeeta Mehta,Robert Doyle,Dietrich Henzler
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0040190
Abstract: The efficacy of partial ventilatory support modes that allow spontaneous breathing in patients with acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) is unclear. The objective of this scoping review was to assess the effects of partial ventilatory support on mortality, duration of mechanical ventilation, and both hospital and intensive care unit (ICU) lengths of stay (LOS) for patients with ALI and ARDS; the secondary objective was to describe physiologic effects on hemodynamics, respiratory system and other organ function.
Limited Re-Sequencing for Mixed-Models with Multiple Objectives, Part II: A Permutation Approach  [PDF]
Patrick R. McMullen
American Journal of Operations Research (AJOR) , 2012, DOI: 10.4236/ajor.2012.21002
Abstract: This research presents an approach to solving the limited re-sequencing problem for a JIT system when two objectives are considered for multiple processes. One objective is to minimize the number of setups; the other is to minimize the material usage rate [1]. For this research effort, each unique permutation of the problem’s demand structure is noted, and used as a mechanism for finding subsequent sequences. Two variants of this permutation approach are used: one employs a Monte-Carlo simulation, while the other employs a modification of Ant-Colony Optimization to find sequences satisfying the objectives of interest. Problem sets from the literature are used for assessment, and experimentation shows that the methodology presented here outperforms methodology from an earlier research effort [3].
Limited Resequencing for Mixed Models with Multiple Objectives  [PDF]
Patrick R. McMullen
American Journal of Operations Research (AJOR) , 2011, DOI: 10.4236/ajor.2011.14025
Abstract: This research presents a problem relevant to production scheduling for mixed models – production schedules that contain several unique items, but each unique item may have multiple units that require processing. The presented research details a variant of this problem where, over multiple processes, resequencing is permitted to a small degree so as to exploit efficiencies with the intent of optimizing the objectives of required set-ups and parts usage rate via an efficient frontier. The problem is combinatorial in nature. Enumeration is used on a variety of test problems from the literature, and a search heuristic is used to compare optimal solutions with heuristic based solutions. Experimentation shows that the heuristic solutions approach optimality, but with opportunities for improvement.
A Genetic Algorithm for Multiple Inspections with Multiple Objectives  [PDF]
Patrick R. McMullen
American Journal of Operations Research (AJOR) , 2013, DOI: 10.4236/ajor.2013.36045
Abstract:  This research presents a genetic algorithm to address the problem where multiple inspections are done to test conformity of multiple product characteristics. The genetic algorithm is employed to find an inspection plan where the multiple inspections are carried out, motivated to optimize two objectives: minimization of the total cost associated with the inspection; and maximization of probability of accepting conforming units. The genetic algorithm includes a constraint to induce variety into the characteristics being tested, so that the inspections are not dominated by “specialized” product characteristics. The resulting solutions are compared to optimal solutions, and it is determined that formidable solutions are found via the Genetic Algorithm approach.
JIT Mixed-Model Sequencing Rules: Is There a Best One?  [PDF]
Patrick R. McMullen
American Journal of Operations Research (AJOR) , 2015, DOI: 10.4236/ajor.2015.51002
Abstract: This research effort compares four sequencing rules intended to smooth production scheduling for mixed-model production systems in a Just-in-Time/Lean manufacturing environment (“JIT” hereafter). Each rule intends to schedule mixed-model production in such a way that manufacturing flexibility is optimized in terms of system utilization, units completed, average in-process inventory, average queue length, and average waiting time. A simulation experiment, where the various sequencing rules are tested against each other in terms of the above production measures, shows that three of the sequencing rules essentially offer the same performance, whereas one of them shows more variation.
Using Baseball Data as a Gentle Introduction to Teaching Linear Regression  [PDF]
Patrick R. McMullen
Creative Education (CE) , 2015, DOI: 10.4236/ce.2015.614148
Abstract: This effort describes a successful classroom exercise to introduce simple and multiple linear regression to working professional MBA students. The exercise starts by exploring the relationship between a baseball team’s payroll with its winning percentage. The exercise then continues with the introduction of additional predictor variables so that the students are able to build a strong predictive model for winning percentage. Student feedback consistently praises the exercise as an effective way to learn about linear regression.
Ant-Colony Optimization for the System Reliability Problem with Quantity Discounts  [PDF]
Patrick R. McMullen
American Journal of Operations Research (AJOR) , 2017, DOI: 10.4236/ajor.2017.72007
Abstract: This research presents an approach based upon ant-colony optimization to address the system reliability problem. For each component of a system, the number of units in parallel needs to be chosen to maximize the reliability for the entire system. As more parallel units are selected, costs increase in a proportional fashion. For this effort, quantity discounts for additional parallel units are considered, and the budget for purchase of parallel units is limited. Ant colony optimization methodology is employed to find an optimal system reliability that satisfies the budget constraint. The methodology is employed for several test problems, and near-optimal solutions are found.
Cell Cycle Regulation and Cytoskeletal Remodelling Are Critical Processes in the Nutritional Programming of Embryonic Development
Angelina Swali, Sarah McMullen, Helen Hayes, Lorraine Gambling, Harry J. McArdle, Simon C. Langley-Evans
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0023189
Abstract: Many mechanisms purport to explain how nutritional signals during early development are manifested as disease in the adult offspring. While these describe processes leading from nutritional insult to development of the actual pathology, the initial underlying cause of the programming effect remains elusive. To establish the primary drivers of programming, this study aimed to capture embryonic gene and protein changes in the whole embryo at the time of nutritional insult rather than downstream phenotypic effects. By using a cross-over design of two well established models of maternal protein and iron restriction we aimed to identify putative common “gatekeepers” which may drive nutritional programming. Both protein and iron deficiency in utero reduced the nephron complement in adult male Wistar and Rowett Hooded Lister rats (P<0.05). This occurred in the absence of damage to the glomerular ultrastructure. Microarray, proteomic and pathway analyses identified diet-specific and strain-specific gatekeeper genes, proteins and processes which shared a common association with the regulation of the cell cycle, especially the G1/S and G2/M checkpoints, and cytoskeletal remodelling. A cell cycle-specific PCR array confirmed the down-regulation of cyclins with protein restriction and the up-regulation of apoptotic genes with iron deficiency. The timing and experimental design of this study have been carefully controlled to isolate the common molecular mechanisms which may initiate the sequelae of events involved in nutritional programming of embryonic development. We propose that despite differences in the individual genes and proteins affected in each strain and with each diet, the general response to nutrient deficiency in utero is perturbation of the cell cycle, at the level of interaction with the cytoskeleton and the mitotic checkpoints, thereby diminishing control over the integrity of DNA which is allowed to replicate. These findings offer novel insight into the primary causes and mechanisms leading to the pathologies which have been identified by previous programming studies.
Processes Underlying the Nutritional Programming of Embryonic Development by Iron Deficiency in the Rat
Angelina Swali, Sarah McMullen, Helen Hayes, Lorraine Gambling, Harry J. McArdle, Simon C. Langley-Evans
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0048133
Abstract: Poor iron status is a global health issue, affecting two thirds of the world population to some degree. It is a particular problem among pregnant women, in both developed and developing countries. Feeding pregnant rats a diet deficient in iron is associated with both hypertension and reduced nephron endowment in adult male offspring. However, the mechanistic pathway leading from iron deficiency to fetal kidney development remains elusive. This study aimed to establish the underlying processes associated with iron deficiency by assessing gene and protein expression changes in the rat embryo, focussing on the responses occurring at the time of the nutritional insult. Analysis of microarray data showed that iron deficiency in utero resulted in the significant up-regulation of 979 genes and down-regulation of 1545 genes in male rat embryos (d13). Affected processes associated with these genes included the initiation of mitosis, BAD-mediated apoptosis, the assembly of RNA polymerase II preinitiation complexes and WNT signalling. Proteomic analyses highlighted 7 proteins demonstrating significant up-regulation with iron deficiency and the down-regulation of 11 proteins. The main functions of these key proteins included cell proliferation, protein transport and folding, cytoskeletal remodelling and the proteasome complex. In line with our recent work, which identified the perturbation of the proteasome complex as a generalised response to in utero malnutrition, we propose that iron deficiency alone leads to a more specific failure in correct protein folding and transport. Such an imbalance in this delicate quality-control system can lead to cellular dysfunction and apoptosis. Therefore these findings offer an insight into the underlying mechanisms associated with the development of the embryo during conditions of poor iron status, and its health in adult life.
Longitudinal impact of a youth tobacco education program
Martin C Mahoney, Joseph E Bauer, Laurene Tumiel, Sarah McMullen, Jeff Schieder, Denise Pikuzinski
BMC Family Practice , 2002, DOI: 10.1186/1471-2296-3-3
Abstract: Twenty-eight schools, which were in relatively close geographic proximity, were randomized into three groups; Group 1 was used to assess whether attitudes/knowledge were changed in the hypothesized direction by the intervention, and if those changes were retained four months later. Groups 2 and 3, were used as comparison groups to assess possible test-retest bias and historical effects. Groups 1 and 3 were pooled to assess whether attitudes/knowledge were changed by the intervention as measured by an immediate post-test. The non-parametric analytical techniques of Wilcoxon-Matched Pairs/Sign Ranks and the Mann-Whitney-Wilcoxon Rank Sums Tests were used to compare proportions of correct responses at each of the schools.Pooled analyses showed that short-term retention on most items was achieved. It was also found that retention on two knowledge items 'recognition that smokers have yellow teeth and fingers' and 'smoking one pack of cigarettes a day costs several hundred dollars per year' was maintained for four months.The findings suggest that inexpensive, one-time interventions for tobacco-use prevention can be of value. Changes in attitudes and knowledge conducive to the goal of tobacco-use prevention can be achieved for short-term retention and some relevant knowledge items can be retained for several months.Given the epidemiology of smoking initiation, a great deal of public health policy and programmatic attention has been directed at youth smoking in the United States [1]. Approximately 80% of tobacco users initiate use before 18 years of age, and if this trend in early initiation of cigarette smoking continues, estimates are that 5 million children aged less than 18 years who are alive today will die prematurely as adults [2].In an effort to discourage initiation of tobacco use, several youth tobacco education programs have been created and are currently available for presentation to elementary school students. Many of these approaches are school-based programs,
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