Van der Waerden's Theorem and Avoidability in Words

Pirillo and Varricchio, and independently, Halbeisen and Hungerbuhler considered the following problem, open since 1994: Does there exist an infinite word w over a finite subset of Z such that w contains no two consecutive blocks of the same length and sum? We consider some variations on this problem in the light of van der Waerden's theorem on arithmetic progressions.Comment: Co-author added; new result

Rapid consolidation of powdered materials by induction hot pressing

A rapid hot press system in which the heat is supplied by RF induction to rapidly consolidate thermoelectric materials is described. Use of RF induction heating enables rapid heating and consolidation of powdered materials over a wide temperature range. Such rapid consolidation in nanomaterials is typically performed by spark plasma sintering (SPS) which can be much more expensive. Details of the system design, instrumentation, and performance using a thermoelectric material as an example are reported. The Seebeck coefficient, electrical resistivity, and thermal diffusivity of thermoelectric PbTe material pressed at an optimized temperature and time in this system are shown to agree with material consolidated under typical consolidation parameters

Monolithic protein stationary phases prepared by the sol-gel method for use in affinity chromatography

Capillary monolithic silica columns used for normal and reversed phase separations offer the advantage of lower backpressure and higher efficiency compared to packed columns. However, capillary monolithic columns have not been applied to affinity chromatography. We used the sol-gel method to encapsulate proteins in a silica matrix for capillary affinity chromatography. A monolithic protein stationary phase was prepared by the tetramethyl orthosilicate procedure. The protein containing sol was injected into a 75um i.d. capillary that had been pretreated with sodium hydroxide. The sol gelled into a rigid micro-porous and macro-porous stationary phase. The porosity of the gel was characterized by scanning electron microscopy and Brunauer-Emmett-Teller adsorption/desorption isotherms. Ubiquitin, bovine serum albumin (BSA), and catalase at different loadings were used in preliminary tests to determine the effects of protein size and concentration on the stationary phase properties. Preliminary separations were performed using the pumps from a capillary electrophoresis instrument with BSA doped monolithic columns

Irritable Bowel Syndrome Pain-related Behaviors and Pain Coping Strategies as Predictors of Women\u27s Daily Activities

The purpose of this study is to discover the predictability of women\u27s daily activities in relation to their irritable bowel syndrome (IBS) pain-related behaviors and coping styles. One hundred seventy-seven women participated in a national survey study using Rome II criteria. Recruitment occurred through medical and graduate students\u27 list serves at the Philadelphia College of Osteopathic Medicine (PCOM), Philadelphia, Pennsylvania; IBS websites; women\u27s healthcare websites; primary care and gastroenterology practices; churches, and a community center. This survey study was conducted face-to-face and via mail-in, using the Coping Strategies Questionnaire-Revised (Hastie, Riley III, & Fillingim, 2004; Riley III & Robinson, 1997; Riley III & Robinson, Geisser, 1999), the West Haven-Yale Multidimensional Pain Inventory (Kerns, Turk, & Rudy, 1985), the Pain Behavior Questionnaire (Phillips & Jahanshahl, 1986), and a Personal Characteristics Questionnaire (Kazdin, 1998a). Results of this investigation suggest that the active and passive coping strategies, in conjunction with the pain behaviors used, impact the IBS pain sufferers\u27 daily activities. D10

An Examination of Innovation in Tennessee\u27s Charter Schools

Similar to other states, charter schools in Tennessee were established to improve student learning, provide options for parents, encourage the use of innovative methods, and provide new opportunities for teachers. With the passage of the TNPublic Charter School Law, the first four charter schools opened in the 2003-04 academic year. Since that time, evidence has accumulated that this cohort of schools has been able to demonstrate many of the purposes outlined in the TN charter school law. For example, teachers and parents have generally reported positive experiences with the schools as well as satisfaction with key outcomes. Additionally, although student achievement results have been mixed, the schools have all successfully renewed their charters. The extent to which the charter schools are being innovative, however, has not been well documented. Using a qualitative collective case study approach, the goal of this paper was to examine if the first cohort of TNcharter schools is utilizing innovative methods. The resulting themes across schools included the use of extended learning time, engaging students as individual learners, adopting a holistic view of education, high-levels of support for the school\u27s mission coupled with participative decision-making, and purposeful parent and community involvement with the schools. When examined in isolation, the charter school practices appear to be well-founded in the research literature, but do not ostensibly seem to be truly new. When the combination of practices is examined, however, then each school appears to provide a unique approach to educating their students, the vast majority of whom are economically disadvantaged and educationally at-risk. Additionally, the schools offered educational methods and opportunities that may not have otherwise been provided in their respective communities. This holistic, contextually-based examination of innovation also offers lessons for adoption and scale-up of practices by other schools

Experimental evaluations of selected sealants to remediate CO₂ leakage

Carbon Dioxide (CO2) sequestration into porous and permeable brine-filled aquifers is seen as one of the most feasible solutions for reducing the amount of greenhouse gases released into the atmosphere from coal-fired power plants. To safely store the CO2, it must be trapped under an impermeable rock acting as a seal. One of the concerns with CO2 sequestration is the generation of new fractures or reopening of existing fractures caused by CO2 injection in the sealing formation. This project evaluates the potential of sealing these fractures by injecting sealing materials into them. These sealing materials need also to stay in place over long term. Therefore the long term thermo-stability of the sealing materials exposed to CO2 has to be addressed. Four sealing materials have been investigated, at subsurface conditions, to study their ability to effectively seal CO2 migration through fractures ranging in size from 250 µ up to 1 mm. The four sealant materials were: paraffin wax, silica-based gel, polymer-based gel, and calcium aluminate-based cement. All four materials significantly reduced the fracture permeability. However, the calcium aluminate-based cement was the most effective sealant agent and was the only sealant that was able to withstand the large differential pressure caused by CO2 or brine injection pressure. Based on the experiments conducted, gels cannot be expected to withstand large pressure differentials in a parallel fracture and therefore the calcium aluminate-based cement is recommended for sealing of fracture widths above half a millimeter. Since cement exposed to CO2 is subjected to the reaction of carbonation, a potential injection scenario is to inject cement first to create a barrier to differential pressures and then follow with a gel as a secondary seal to create a chemically stable sealing agent exposed to CO2 --Abstract, page iii

An assessment of periphyton communities in five Upper Peninsula streams, MI

This project quantified lotic periphyton community change from May 2018-October 2018 in five, first and second-order Lake Superior tributary streams. Using periphyton communities, land use, geology, and abiotic factors pertinent to stream ecosystems we evaluated periphyton community succession. Using periphytometers, periphyton communities were collected and identified monthly to quantify community succession. Total phosphorus and total Kjeldahl nitrogen were measured monthly during the study. Depth, velocity, specific conductivity, and canopy cover were measured to quantify some of the physical factors within the streams. Nonmetric multidimensional scaling analysis indicated that the periphyton communities were similar between streams (ADONIS p-value =0.73) but was changing seasonally (ADONIS p-value \u3c0.001). Dominant diatom taxa found were Synedra, Nitzschia, Melosira, Navicula, and Diatoma. Principal component analysis found that most streams had similar characteristics throughout the sampling period but depth. Chemical analysis from the streams indicated that these systems contained low nutrients but were classified as oligotrophic based on the trophic state index. Nutrients in the streams were very low; total phosphorus ranged from 50-70 μg/L meaning the streams meet the oligotrophic threshold. Nitrogen concentrations within these streams peaked at 1.00 mg/L following leaf abscission from the riparian vegetation in the fall but was found to be \u3c0.5 mg/L throughout the rest of the sampling period. It has been hypothesized that Lake Superior is beginning to undergo the process of ultra-oligotrophication or when total phosphorus levels are \u3c1 μg/L within the water column. The Lake Superior basin could be greatly impacted by climate change, introduction of invasive species, and potential warming air temperatures, which could accelerate ultra-oligotrophication within the basin and cause a reduction in biodiversity of Lake Superior and its tributaries