1,849 research outputs found

    Pointing Control and Stabilization of the High-Energy UV Laser for Laser-Assisted Charge Exchange

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    Laser-Assisted Charge Exchange (LACE) is an experimental method of charge exchange injection into a proton accumulator ring that is being developed at the Spallation Neutron Source (SNS) in Oak Ridge National Laboratory (ORNL) as an alternative to hazardous injection foils. The current scheme of LACE requires a high-energy, low-repetition-rate UV (355 nm) laser beam (140 mJ pulses at 10 Hz) to be transported over 65 meters to the laser-particle interaction point (IP) in a high-radiation area of the accelerator. Thermal effects and other disturbances along the free-space laser transport line cause the beam to slowly drift away from the IP and jitter at a frequency comparable to the pulse repetition rate. A control system was designed, simulated, and constructed to stabilize the pointing of the laser beam to allow stable operation of the experiment. The laser pointing stabilization system is based on feedback between Complementary Metal-Oxide-Semiconductor (CMOS) cameras and a steering mirror with piezoelectric actuators. A PC running custom-made LabVIEW software acts a controller in open- and closed-loop modes, as well as a diagnostic tool. An analytical model of the system was used for optimization of the control law, and the system performs as well in the field as it did in laboratory tests. The laser pointing stabilization system eliminates the slow drift by keeping the beam aligned at the IP for an indefinite amount of time, and the jitter is reduced to the level of the pulse-to-pulse fluctuations

    Preservice music students explore African music in an Australian tertiary context

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    marshall 0 0 2014-10-08T21:19:00Z 2014-10-08T23:14:00Z 1 215 1229 10 2 1442 14.0 Normal 0 false false false EN-US JA X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:12.0pt; font-family:Cambria; mso-ascii-font-family:Cambria; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:Cambria; mso-hansi-theme-font:minor-latin;} Australia is a very diverse country where difference is celebrated and embraced as a way forward to learn of other people, their music and culture. This paper focuses on the teaching and learning of African music where music and culture is shared in a music workshop with preservice teacher education students. The music-as-culture approach presents an opportunity for preservice teachers to experience, connect and engage with non-Western music. This paper forms part of a research project titled &ldquo;Pre-service teacher attitudes and understandings of Music Education&rdquo; that started in 2013. Drawing on data from student questionnaires, author participant observation and reflective practice in April 2014, the findings highlight the experiences and practical engagement of an African music workshop in teacher education courses in Queensland (Australia). The authors assert as music tertiary educators they have a responsibility to teach their students about different music and songs from other lands. The workshop was concerned with the experience as it was lived, felt and undertaken (Sherman, Webb &amp; Andrews, 1983). Generalisations cannot be made from such a small qualitative research sample, however, it is hoped that the reflections made by the students and authors are insightful and will provide a platform for further dialogue regarding what is relevant and valuable for student teachers as they prepare to be future music teachers. <!--EndFragment--

    An Economic Analysis of the Potential Influence of Carbon Credits on Farm Management Practices

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    The objective of the 1997 Kyoto agreement was to limit greenhouse gas (GHG) emissions among signatory countries and thereby slow global warming. Under the agreement, Canada has committed itself to reduce GHGs over the next decade by 6 percent from estimated 1990 levels. Debate has now begun on the appropriate government policies that will induce the desired GHG reductions. Regulations could be in the form of direct controls or economic incentives, such as a subsidy/tax system or an emission trading system. The success of the U.S. emission market for SO2 (Schmalenseeet al., 1998) has generated growing interest in the use of a similar market mechanism for carbon (Holmes and Friedman, 2000). The existence of a carbon credit market presents the agricultural sector with another potential revenue source (Sandor and Skees, 1999). While agriculture contributes approximately 10 percent of Canada’s greenhouse gas emissions, it also has the potential to sequester carbon through strategies such as zero tillage, reduced summer fallow and improved grazing. These sequestration activities could be incorporated into an emission trading system and create a “carbon credit†for each unit of CO2 that is removed from the atmosphere. Firms with high emission reduction costs could then buy these credits rather than bear the large abatement costs associated with reducing their GHG emission levels. The perception is that the marginal cost of abatement for agriculture is less than that for other sectors (McCarl and Schneider, 2000). Thus, farmers may be able to profit by selling credits for activities that sequester carbon. An example of such a transaction was the purchase of carbon credits from Iowa farmers who adopted no-till by a consortium of Canadian energy companies (GEMCO) (Lessiter, 1999). Whether the development of a carbon credit market will affect the management decisions of an Ontario crop farmer isthe focus of this study.Agricultural and Food Policy, Farm Management,

    Partial Information Decomposition as a Unified Approach to the Specification of Neural Goal Functions

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    In many neural systems anatomical motifs are present repeatedly, but despite their structural similarity they can serve very different tasks. A prime example for such a motif is the canonical microcircuit of six-layered neo-cortex, which is repeated across cortical areas, and is involved in a number of different tasks (e.g.sensory, cognitive, or motor tasks). This observation has spawned interest in finding a common underlying principle, a 'goal function', of information processing implemented in this structure. By definition such a goal function, if universal, cannot be cast in processing-domain specific language (e.g. 'edge filtering', 'working memory'). Thus, to formulate such a principle, we have to use a domain-independent framework. Information theory offers such a framework. However, while the classical framework of information theory focuses on the relation between one input and one output (Shannon's mutual information), we argue that neural information processing crucially depends on the combination of \textit{multiple} inputs to create the output of a processor. To account for this, we use a very recent extension of Shannon Information theory, called partial information decomposition (PID). PID allows to quantify the information that several inputs provide individually (unique information), redundantly (shared information) or only jointly (synergistic information) about the output. First, we review the framework of PID. Then we apply it to reevaluate and analyze several earlier proposals of information theoretic neural goal functions (predictive coding, infomax, coherent infomax, efficient coding). We find that PID allows to compare these goal functions in a common framework, and also provides a versatile approach to design new goal functions from first principles. Building on this, we design and analyze a novel goal function, called 'coding with synergy'. [...]Comment: 21 pages, 4 figures, appendi

    The 24 hour lung function time profile of olodaterol once daily versus placebo and tiotropium in patients with moderate to very severe chronic obstructive pulmonary disease

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    Background: Olodaterol is a once-daily long-acting β2-agonist being investigated for the treatment of chronic obstructive pulmonary disease, with ≥ 24 hour bronchodilator activity. Methods: Two replicate, randomized, double-blind, four-way crossover (6-week treatment periods), active (tiotropium 18 μg via HandiHaler®)- and placebo-controlled trials were conducted to evaluate the 24 hour forced expiratory volume in 1 second (FEV1) profile of olodaterol (5 and 10 μg) once daily (via Respimat®). Patients continued with inhaled corticosteroids and xanthines. Spirometry was performed at baseline and over the entire 24 hour post-dose period at week 6 of each treatment phase. Co-primary end points were change from study baseline (response) in FEV1 area under the curve from 0–12 hours (AUC0–12) and FEV1 AUC from 12–24 hours (AUC12–24); key secondary end point was FEV1 AUC from 0–24 hours response. Results: In study 1222.39, there was a significant difference from placebo in FEV1 AUC0–12 and AUC12–24 responses (P<0.0001) with olodaterol 5 μg (0.185 and 0.131 L) and 10 μg (0.207 and 0.178 L) at 6 weeks; similar results were observed for tiotropium (0.173 and 0.123 L). In study 1222.40, responses were 0.197 and 0.153 L with olodaterol 5 μg, 0.221 and 0.170 L with 10 μg, and 0.221 and 0.164 L with tiotropium versus placebo (P<0.0001). Incidence of adverse events was comparable across treatments. Conclusions: These data confirm the 24 hour lung-function efficacy profile of once-daily olodaterol, with FEV1 responses comparable to tiotropium

    THE NATURAL HISTORY AND CAPTIVE HUSBANDRY OF THE SALT CREEK TIGER BEETLE, \u3ci\u3eCicindela (=Ellipsoptera) nevadica lincolniana\u3c/i\u3e (COLEOPTERA: CARABIDAE).

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    Tiger beetles have long been admired for their mix of beauty, speed, and ferocious hunting abilities (Pearson 2011). The tiger beetles are some of the fastest insects on the planet with the Australian species, Cicindela hudsoni being clocked at 2.5meters per second (Merrit 1999). The tiger beetles run so fast that they are temporarily blinded when they are engaged in the high speed pursuit of their prey (Friedlander 2014). However, despite their speed, and the joy they bring to many enthusiasts, tiger beetles are unable to outrun the destruction and degradation of their habitats by human activities, and an estimated 15 percent of the 255 described species and subspecies of North American tiger beetles are now threatened with extinction (Pearson 2011). Several species of tiger beetle are very niche specialized and will only inhabit certain areas where the conditions are just right for their survival (Pearson 2006). The saline wetlands of Lancaster and Saunders counties located in eastern Nebraska are home to one such beetle. An endemic subspecies of the Nevada Tiger Beetle, Cicindela (=Ellipsoptera) nevadica, calls these saline wetlands home. This beetle is aptly named the Salt Creek Tiger beetle, Cicindela (=Ellipsoptera) nevadica lincolniana, due to its presence only along Little Salt Creek and associated tributaries (Spomer, et al. 2007). The olive-colored, 5mm long beetles are dependent on the saline wetlands, and due to the rapid destruction of their habitat by farmers and developers, are now threatened with extinction (Spomer, et al.2007). The population numbers for the C. n. lincolniana range from 150-1000 adults a year, making this species one of the most endangered insects in North America (Higley & Spomer 2001). The following paper gives a brief overview of the natural history of the C. n. lincolniana and outlines the efforts of the Omaha’s Henry Doorly Zoo and Aquarium in its attempt to captive rear this species, and save Nebraska’s native tigers and the wetlands they call home

    Effective Organizational Practices for Middle and High School Grades

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    At the request of the Accountability Review Council, Research for Action identified effective organizational practices used by better performing schools serving substantial numbers of low income middle and high school students in the School District of Philadelphia. These practices are organized into three spheres: Conditions for Teaching, Student-Centered School Community, and Instructional Program. For each sphere, the report offers broad strategies and specific practices to enact the strategies. Nuanced school case studies show how the practices can work synergistically and coherently in schools to help students succeed
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