The Complexity of Integrating Routing Decisions in Public Transportation Models

To model and solve optimization problems arising in public transportation, data about the passengers is necessary and has to be included in the models in any phase of the planning process. Many approaches assume a two-step procedure: in a first step, the data about the passengers is distributed over the public transportation network using traffic-assignment procedures. In a second step, the actual planning of lines, timetables, etc. takes place. This approach ignores that for most passengers there are many possible ways to reach their destinations in the public transportation network, thus the actual connections the passengers will take depend strongly on the decisions made during the planning phase. In this paper we investigate the influence of integrating the traffic assignment procedure in the optimization process on the complexity of line planning and aperiodic timetabling. In both problems, our objective is to maximize the passengers\u27 benefit, namely to minimize the overall travel time of the passengers in the network. We present new models, analyze NP-hardness results arising from the integration of the routing decisions in the traditional models, and derive polynomial algorithms for special cases

A ruptured vulvar labial artery pseudoaneurysm causes a secondary postpartum hemorrhage: A case report.

Background:Postpartum hemorrhage is the most common cause of maternal morbidity in the United States. However, secondary postpartum hemorrhage is rare and includes pseudoaneurysms, which represent only 3.3% of all cases of secondary postpartum hemorrhage. Vulvar labial artery pseudoaneurysm had never been reported in the literature. Case:This is a case of ruptured vulvar labial pseudoaneurysm leading to secondary postpartum hemorrhage. Computerized tomography angiography showed it to be located in a distal branch of the vulvar labial artery. This location is unique, although there are reported cases of pseudoaneurysms in the uterine artery. The patient was successfully treated with arterial embolization. Conclusion:Recognition of a ruptured pseudoaneurysm as the cause of postpartum hemorrhage allows for its proper management by arterial embolization

Knowledge of botulism among health care students

Scholarly project (M.S.)

Examination of the effects of selected factors on the talin-actin interaction

Talin is an adhesion plaque protein believed to be involved in linking actin filaments to cell membranes. In these studies I examined the effects of selected factors on the ability of talin and its 190 kDa proteolytic fragment to interact with actin. A modified method for purifying talin from avian smooth muscle was devised. Cosedimentation assays showed that increasing amounts of talin bound to actin filaments as pH was decreased from 7.4 to 6.4. Talin\u27s ability to increase viscosity of F-actin solutions also was increased with decreasing pH within this range. Electron microscope observations supported a pH-dependent, actin filament crosslinking activity for talin. The ability of talin to crosslink actin filaments was markedly decreased with increasing ionic strength, regardless of pH. Increasing the molar ratio of talin to actin enhanced the interaction. Viscometry studies showed that increasing temperature from 4∘ to 37∘C increased the ability of talin to interact with actin. Talin crosslinked actin filaments into networks and bundles in times as short as 5 min at pH 6.4 and low ionic strength. Talin also bound to and crosslinked preformed actin filaments to the same extent as it did when filaments were formed in its presence. The effects of pH and ionic strength on the ability of talin to bind to actin were shown to be reversible;The 190 kDa talin fragment did not bind actin strongly under conditions that favored the interaction between intact talin and actin (pH 6.4, low ionic strength). However, when the pH was lowered to 6.0, the 190 kDa fragment crosslinked actin filaments into networks and bundles. The effects of the adhesion plaque proteins filamin, vinculin, [alpha]-actinin, and tropomyosin on the ability of talin to cosediment with actin filaments were also studied. Filamin and tropomyosin could reduce the amount of talin that cosedimented with actin, but did not eliminate the talin-actin interaction. Vinculin and [alpha]-actinin did not measurably affect the ability of talin to cosediment with actin. Overall, results from these experiments support a role for talin in the organization and attachment of actin filaments at adhesion plaques

Chief Executive Officers of California Environmental Organizations: A Study of Personal Values Congruence with Organizational Mission

This study surveyed the Chief Executive Officers of 300 California environmental organizations to investigate whether these officers were personally committed to their organizations\u27 missions as demonstrated by 1) past and present activities in their personal lives that indicated personal values similar to those espoused by the organization, and 2) their intent to stay with their organization. It was hypothesized that the level of activity in the personal lives of the CEOs demonstrating personal commitment to their organizations would be positively related to their intent to stay with their organizations. It was also expected that there would be a negative association between the size of the environmental organization, and the amount of evidence indicating that the CEO had personal values that were congruent with those of the organization\u27s mission. This study demonstrated that the congruence of CEO personal values and organizational mission had a significantly positive effect on the intended length of stay of CEOs with their organizations. It also substantiated that individuals with high levels of values congruence (and therefore intent to stay) were strongly influenced by the environmental mission of the organization when accepting their current position. This has implications for the selection of future chief executive officers

Cognitive Demand of Teacher-Created Mathematics Assessments

This study analyzed assessments created by middle school mathematics teachers participating in a large scale research project in the Northwestern United States. Assessments were coded using the frameworks of Webb’s Depth of Knowledge (DOK) for mathematics content (2002), and Smith and Stein’s Levels of Demand (LOD) (1998). Teachers in the study were instructed to create an assessment using 5 common-items provided by the research team and 5 of their own sourced items. Assessment items were coded using each framework and data was collected based on the DOK framework, LOD framework, and grade level. Findings indicate on average, teachers assessments were relatively balanced between procedures and conceptual understanding and balanced between recollection, application of a skill/concept, and explanation of thinking. When looking at data based on grade level, assessments tended to address higher-level thinking as grade levels progressed. However when common-items were not included in the analysis, assessments tended to address the items using procedural thinking, and less frequently required explanation of thinking for solutions

Developing the 21st Century Skills of Creativity, Collaboration and Information Fluency in a Kindergarten Classroom

The research question addressed in this project was, how can kindergarten students develop the 21st Century Skills of creativity, collaboration and information fluency through technology integration? It documents one teacher’s creation of a literacy based curriculum unit that gives kindergarten students opportunities to grow their 21st Century Skills, using the iPad as the learning tool. Key influences for this capstone include the National Association for the Education of Young Children’s new standards for technology integration in early education classrooms, as well as the International Literacy Association’s new standards for literacy education. Richardson’s research on the change in learning and teacher’s roles with the influx of technology in the 21st century is also an important influence. The author describes the reasoning behind the curriculum unit developed, as well as the significance of teaching the skills of creativity, collaboration and information fluency to 21st Century learners

Effect of Carbon Black Electrocatalyst Thickness and Composition on Electrosynthesis of Hydrogen Peroxide on Gas Diffusion Electrodes

The in-situ electrosynthesis of hydrogen peroxide (H2O2) from reduction of oxygen is a promising method to produce a strong oxidant and disinfectant for application in the water and wastewater treatment industry. Capable of producing low concentrations of H2O2 with no aeration requirements and harmless by-products of water and oxygen, the electrosynthesis of H2O2 using gas diffusion electrodes is advantageous. This research examines the impact that electrocatalyst thickness and composition have on the production efficiency of H2O2 at the gas diffusion layer of a gas diffusion electrode. From these results, the optimum electrocatalyst loading and composition with its respective energy requirements is assessed. An increase in electrocatalyst loading on the gas diffusion layer saw a greater thickness of the electrocatalyst layer, increasing the perpendicular diffusion pathway required for H2O2 to reach the electrolyte solution. At a current density of 1 mA/cm2, the lowest electrocatalyst loading of 0.5 mg/cm2 produced the highest H2O2 concentration of 807.54 mg/L and maximum current coulombic efficiency of 53%. The H2O2 produced from the additional three electrocatalyst loadings of 1.5, 3.0, and 5.0 mg/cm2 decreased linearly with increasing loading. An increase in the length of the diffusion pathway allows more time for H2O2 to accumulate and degrade to H2O or O2. As current density was increased, higher yields of H2O2 were achieved for all loadings, suggesting less chemical degradation of H2O2 to O2 as the higher electrocatalyst loadings significantly improved current efficiencies to match the lower electrocatalyst loadings. An energy input analysis calculating the mass produced/energy input in kg H2O2/kWh demonstrated a benefit in selecting higher electrocatalyst loadings at higher current densities. Although the highest electrocatalyst loading of 5.0 mg/cm2 produced the lowest concentrations of H2O2 at a current density of 5 mA/cm2, it accomplishes the greatest mass produced/energy input of 3.84 kg H2O2/kWh. The effect of electrocatalyst composition was examined as electrocatalyst loadings of 1.5 and 5.0 mg/cm2 were tested with and without proton exchange polymer, Nafion, in the electrocatalyst carbon ink. The electrocatalyst loadings comprised of a carbon ink without Nafion resulted in greater H2O2 concentrations and current efficiencies, with smaller differences between loadings compared to the results for loadings containing Nafion. At the cathode surface, pH increases rapidly, where H2O2 exists as its anion, hydroperoxide (HO2-). Interaction with the negatively charged sulfonic groups (SO3-) in the proton exchange polymer, Nafion, causes resistance to the mass transport of HO2- through the electrocatalyst layer. The HO2- can then accumulate, be degraded, and result in lower measured concentrations of H2O2 in the electrolyte

Regulation Of Choline Acetyltransferase In Rat Hippocampal Synaptosomes

Choline acetyltransferase (ChAT; EC 2.3.1.6) catalyses the biosynthesis of acetylcholine (ACh) from choline and acetylCoenzyme A in cholinergic neurons. Within nerve terminals, this enzyme exists in both cytosolic and membrane-bound forms, although the role of the latter fraction is not clear. ChAT is clearly subject to long-term regulation (over periods of hours to days), likely through alterations in protein synthesis, however very little is known about short-term regulation (seconds to minutes). Therefore, the goals of this study were to determine the mechanisms of short-term regulation of ChAT activity and to elucidate the physiological role of membrane-bound ChAT in ACh biosynthesis.;Using synaptosomes prepared from rat brain hippocampus as a model of intact nerve terminals, approximately 80% of total ChAT activity was found in the cytoplasm and could be further divided into a water-soluble fraction (20%) and sodium phosphate-soluble fraction (60%), while the remaining ChAT (15-20%) appeared to be membrane-bound. Interestingly, only the specific activity of membrane-bound ChAT was significantly increased, in a calcium-dependent manner, following depolarization of intact synaptosomes by both 40 mM KCl and 50 {dollar}\mu{dollar}M veratridine, agents which induce ACh release and subsequent choline uptake. Since W-7, an inhibitor of calcium-calmodulin kinase II, attenuated the depolarization-induced activation of membrane-bound ChAT, protein phosphorylation was examined as a mechanism of short-term regulation. Under resting conditions, only cytosolic ChAT appeared to exist as a phosphoprotein, the abundance of which was calcium-dependent. Furthermore, the pattern of phosphorylation neither correlated with enzyme activity, nor was altered by nerve terminal depolarization. Since the specific activity of cytosolic ChAT was not altered by any experimental manipulation, it was subdivided into water-soluble and sodium phosphate-soluble enzyme fractions. Subsequently, it was found that reduction of intracellular calcium concentration, by lowering the extracellular calcium concentration, reduced membrane-bound ChAT and water-soluble ChAT activities and concomitantly increased sodium phosphate-soluble ChAT activity. These alterations in specific activity were accompanied by parallel changes in both the V{dollar}\sb{lcub}\rm max{rcub}{dollar} and the amount of ChAT-immunoreactive protein in each fraction, suggesting translocation of the enzyme between cytosolic and membrane-bound pools and within cytosolic pools. Finally, to assess the physiological role of membrane-bound ChAT, an experimental strategy was developed based upon the observation that enzyme activity was sensitive to alterations in chloride ion concentration. Under these conditions membrane-bound ChAT did not appear to regulate basal ACh biosynthesis.;In summary, translocation of enzyme protein may be involved in the short-term regulation of ChAT activity within cholinergic nerve terminals. Furthermore, cytosolic ChAT appeared to play the predominant role in the regulation of basal ACh synthesis