The Algebra of Strand Splitting. II. A Presentation for the Braid Group on One Strand

Presentations are computed for a braided version BV of Thompson's group V and for V itself showing that there is an Artin group/Coxeter group relation between them. The presentation for V is obtained from that for BV by declaring all that all generators are involutions.Comment: 15 page

Investigating Dielectric Properties of Sintered Polymers for Rapid Manufacturing

Selective Laser Sintering (SLS) of polymers is the leading technology in the growing field of Rapid Manufacturing. High Speed Sintering (HSS) is a process that offers the potential to reduce costs and processing times and thus open significant new markets for Rapid Manufactured parts. Much academic research has been performed with respect to mechanical properties of Rapid Manufactured parts, however the area of electrical properties has received little attention to date. Electrical properties are obviously important in applications that will involve embedding of circuits with Rapid Manufactured 3D objects. However electrical properties are also important for a wide variety of electrical products where Rapid Manufactured parts can be used as housings etc. This paper focuses on the dielectric properties of parts made by SLS and HSS and compares properties with those for conventionally processed polymers. Dielectric strength results show that SLS parts are comparable with injection moulded parts, while HSS parts are inferior to SLS parts. Dielectric constant and dissipation factor results show that HSS parts are comparable with injection moulded parts, whilst SLS parts have superior properties. The presence of porosity (SLS and HSS) and the presence of carbon (HSS) are suggested as reasons behind the variation in dielectric properties when compared with injection moulded parts.Mechanical Engineerin

Evaluating Opportunities and Barriers to Improving the Energy Efficiency of Small Nebraska Wastewater Treatment Plants

Wastewater treatment plants (WWTP)s account for about 0.8% of U.S. electricity use. Small WWTPs serving communities of populations less than 10,000 accounts for 95% of treatment plants in Nebraska. These plants are significantly less efficient compared to large systems and thus improving their energy efficiency (E2) is a growing focus in efforts to reduce greenhouse gas emissions associated with their operation. Energy use of plant unit operations was evaluated for several plants and included analysis of energy for space heating. Specific infrastructure and/or operational changes reported by operators following an E2 benchmarking project were evaluated by quantifying the change in annual billed energy use. Barriers to implementing E2 improvements were ranked by operators in a one-page survey. Supplemental observations from plant assessments occurring throughout the E2 benchmarking project and fifteen subsequent energy assessments were provided. Aeration was identified as the largest energy use (66-73%) of total process energy use and space heating accounted for 4-34% of total plant energy use. Changes were reportedly being made at 19 plants (37% of respondents), with 12 plants reporting changes recommended in the previous benchmarking letters. Energy bills collected for 13 plants reporting changes had 9 plants showing energy reductions of 4-35% and an approximate $39,000 of annual cost savings, with the largest reductions involving the use of VFDs. These plants showed an 8.5% average reduction in energy compared to a 1.2% reduction shown by 16 plants reporting to have not made changes. Survey responses from 41 operators showed that financial related barriers and lack of time or other priorities are the largest barriers for small municipalities in making E2 improvements. Organizational issues also exist within small municipalities in which energy management is not prioritized and often is neglected. Plants reporting making changes had reported lack of staff of awareness as less of a relevant barrier compared to plants reporting to have not made changes. This may suggest that raising awareness about E2 can potentially lead to greater implementation of changes. Advisor: Bruce I. Dvora

Evaluating Opportunities and Barriers to Improving the Energy Efficiency of Small Nebraska Wastewater Treatment Plants

Wastewater treatment plants (WWTP)s account for about 0.8% of U.S. electricity use. Small WWTPs serving communities of populations less than 10,000 accounts for 95% of treatment plants in Nebraska. These plants are significantly less efficient compared to large systems and thus improving their energy efficiency (E2) is a growing focus in efforts to reduce greenhouse gas emissions associated with their operation. Energy use of plant unit operations was evaluated for several plants and included analysis of energy for space heating. Specific infrastructure and/or operational changes reported by operators following an E2 benchmarking project were evaluated by quantifying the change in annual billed energy use. Barriers to implementing E2 improvements were ranked by operators in a one-page survey. Supplemental observations from plant assessments occurring throughout the E2 benchmarking project and fifteen subsequent energy assessments were provided. Aeration was identified as the largest energy use (66-73%) of total process energy use and space heating accounted for 4-34% of total plant energy use. Changes were reportedly being made at 19 plants (37% of respondents), with 12 plants reporting changes recommended in the previous benchmarking letters. Energy bills collected for 13 plants reporting changes had 9 plants showing energy reductions of 4-35% and an approximate $39,000 of annual cost savings, with the largest reductions involving the use of VFDs. These plants showed an 8.5% average reduction in energy compared to a 1.2% reduction shown by 16 plants reporting to have not made changes. Survey responses from 41 operators showed that financial related barriers and lack of time or other priorities are the largest barriers for small municipalities in making E2 improvements. Organizational issues also exist within small municipalities in which energy management is not prioritized and often is neglected. Plants reporting making changes had reported lack of staff of awareness as less of a relevant barrier compared to plants reporting to have not made changes. This may suggest that raising awareness about E2 can potentially lead to greater implementation of changes. Advisor: Bruce I. Dvora

Noncontact GMR measurements of synthetic spin valves using IR reflection spectroscopy

The magnetorefractive effect has been used in infrared reflection spectroscopy to study the magnetotransport properties of synthetic spin valves. This optical noncontact technique shows excellent correlation with the electrical giant magnetoresistance data

Citizen science and crowdsourced data collection, not government statistics, provide the most reliable count of citizen fatalities by police

In 2016 one thousand ninety-two civilians were killed by the police in the United States. When civilians die during police encounters they lose not only their right to due process, but also their chance to be counted. Matthew J. Thompson and Chris M. Smith argue that since the fatal police shooting of Michael Brown in August 2014, more is known about fatal police violence than ever before due to an increase not in official government statistics but in citizen crowdsourced data collection

Corticosteroids for the common cold

BACKGROUND: The common cold is a frequent illness, which, although benign and self limiting, results in many consultations to primary care and considerable loss of school or work days. Current symptomatic treatments have limited benefit. Corticosteroids are an effective treatment in other upper respiratory tract infections and their anti‐inflammatory effects may also be beneficial in the common cold. This updated review has included one additional study. OBJECTIVES: To compare corticosteroids versus usual care for the common cold on measures of symptom resolution and improvement in children and adults. SEARCH METHODS: We searched Cochrane Central Register of Controlled Trials (CENTRAL 2015, Issue 4), which includes the Acute Respiratory Infections (ARI) Group's Specialised Register, the Database of Reviews of Effects (DARE) (2015, Issue 2), NHS Health Economics Database (2015, Issue 2), MEDLINE (1948 to May week 3, 2015) and EMBASE (January 2010 to May 2015). SELECTION CRITERIA: Randomised, double‐blind, controlled trials comparing corticosteroids to placebo or to standard clinical management. DATA COLLECTION AND ANALYSIS: Two review authors independently extracted data and assessed trial quality. We were unable to perform meta‐analysis and instead present a narrative description of the available evidence. MAIN RESULTS: We included three trials (353 participants). Two trials compared intranasal corticosteroids to placebo and one trial compared intranasal corticosteroids to usual care; no trials studied oral corticosteroids. In the two placebo‐controlled trials, no benefit of intranasal corticosteroids was demonstrated for duration or severity of symptoms. The risk of bias overall was low or unclear in these two trials. In a trial of 54 participants, the mean number of symptomatic days was 10.3 in the placebo group, compared to 10.7 in those using intranasal corticosteroids (P value = 0.72). A second trial of 199 participants reported no significant differences in the duration of symptoms. The single‐blind trial in children aged two to 14 years, who were also receiving oral antibiotics, had inadequate reporting of outcome measures regarding symptom resolution. The overall risk of bias was high for this trial. Mean symptom severity scores were significantly lower in the group receiving intranasal steroids in addition to oral amoxicillin. One placebo‐controlled trial reported the presence of rhinovirus in nasal aspirates and found no differences. Only one of the three trials reported on adverse events; no differences were found. Two trials reported secondary bacterial infections (one case of sinusitis, one case of acute otitis media; both in the corticosteroid groups). A lack of comparable outcome measures meant that we were unable to combine the data. AUTHORS' CONCLUSIONS: Current evidence does not support the use of intranasal corticosteroids for symptomatic relief from the common cold. However, there were only three trials, one of which was very poor quality, and there was limited statistical power overall. Further large, randomised, double‐blind, placebo‐controlled trials in adults and children are required to answer this question