The Anisotropic Bak-Sneppen model

The Bak-Sneppen model is shown to fall into a different universality class with the introduction of a preferred direction, mirroring the situation in spin systems. This is first demonstrated by numerical simulations and subsequently confirmed by analysis of the multitrait version of the model, which admits exact solutions in the extremes of zero and maximal anisotropy. For intermediate anisotropies, we show that the spatiotemporal evolution of the avalanche has a power law `tail' which passes through the system for any non-zero anisotropy but remains fixed for the isotropic case, thus explaining the crossover in behaviour. Finally, we identify the maximally anisotropic model which is more tractable and yet more generally applicable than the isotropic system

Left lateralization in autobiographical memory: An fMRI study using the expert archival paradigm

In brain-imaging and behavioural research, studies of autobiographical memory have higher ecological validity than controlled laboratory memory studies. However, they also have less controllability over the variables investigated. Here we present a novel technique—the expert archival paradigm—that increases controllability while maintaining ecological validity. Stimuli were created from games played by two international-level chess masters. We then asked these two players to perform a memory task with stimuli generated from their own games and stimuli generated from other players’ games while they were scanned using fMRI. We found a left lateralised pattern of brain activity which was very similar in both masters. The brain areas activated were the left temporo-parietal junction and left frontal areas. The expert archival paradigm has the advantage of not requiring an interview to assess the participants’ autobiographical memories, and affords the possibility of measuring their accuracy of remembering as well as their brain activity related to remote and recent memories. It can also be used in any field of expertise, including arts, sciences and sports, in which archival data are available

Simulating corporate income tax reform proposals with a dynamic CGE model

Opinion leaders and policy makers in the United States have turned their focus to the corporate income tax, which now has the highest statutory rate in the developed world. Using a dynamic computable general equilibrium model (the “NCPA-DCGE Model”), we simulate alternative policies for reducing the U.S. corporate income tax. We find that reductions in the corporate income tax rate result in significant positive impacts on output, investment, capital formation, employment, and household well-being (for almost all deciles). All of the hypothesized reforms also result in a more-streamlined public sector. These results are plausible insofar as the DCGE model from which they are obtained is parameterized by plausible elasticity assumptions, and incorporates the adjustments in prices, output, employment and investment that result from changes in tax policy

The validity of capillary blood sampling in the determination of human growth hormone concentration during exercise in men

This is an open access article - Copyright © 2004 BMJ Publishing Group LtdBACKGROUND: Studies measuring human growth hormone (hGH) in blood during exercise have mainly used venous sampling. The invasive nature of this procedure makes evaluation of hGH impossible in various exercise environments. OBJECTIVE: To determine whether capillary sampling could offer an alternative sampling method. METHODS: Capillary and venous blood samples were collected for determination of hGH at the end of each exercise stage during an incremental exercise test in 16 male club level competitive cyclists (mean (SD) age 30.8 (8.0) years, body mass 72.2 (7.1) kg, body fat 12.9 (3.5)%, peak oxygen consumption 4.18 (0.46) l⋅min−1). Linear regression, from a plot of venous v capillary blood hGH concentration, showed a correlation coefficient of r = 0.986 (p<0.001). When geometric means and log transformations were used, a coefficient of variation of 14.2% was demonstrated between venous and capillary flow for hGH concentration. The mean ratio limits of agreement were 0.62 (1.72)—that is, 95% of the ratios were contained between 0.36 and 1.07, with a mean of 0.62. CONCLUSIONS: Capillary blood sampling is an acceptable alternative to venous sampling for determining hGH concentration during rest and exercise. Sample sites should not be used interchangeably: one site should be chosen and its use standardised

Brain Localisation of Memory Chunks in Chessplayers

Chess experts store domain-specific representations in their long-term memory; due to the activation of such representations, they perform with high accuracy in tasks that require the maintenance of previously seen information. Chunk-based theories of expertise (chunking theory: Chase & Simon, 1973; template theory: Gobet & Simon, 1996) state that expertise is acquired mainly by the acquisition and storage in long-term memory of familiar chunks that allow quick recognition. We tested some predictions of these theories by using fMRI while chessplayers performed a recognition memory task. These theories predict that chessplayers access long-term memory chunks of domain-specific information, which are presumably stored in the temporal lobes. We also predicted that the recognition memory tasks would activate working memory areas in the frontal and parietal lobes. These predictions were supported by the data

Simultaneous measurement of multiple parameters of a subwavelength structure based on the weak value formalism

A mathematical extension of the weak value formalism to the simultaneous measurement of multiple parameters is presented in the context of an optical focused vector beam scatterometry experiment. In this example, preselection and postselection are achieved via spatially-varying polarization control, which can be tailored to optimize the sensitivity to parameter variations. Initial experiments for the two-parameter case demonstrate that this method can be used to measure physical parameters with resolutions at least 1000 times smaller than the wavelength of illumination

The Use of Peer Mentoring to Decrease Stress in Student Registered Nurse Anesthetists

Nurse anesthesia programs throughout the nation are extremely competitive with strict admissions criteria and demanding curriculum. Students enrolled in these programs, termed Student Registered Nurse Anesthetists (SRNAs), experience high average daily stress levels throughout their enrollment in a nurse anesthesia program (NAP). This quantitative study examined whether there is a decrease in SRNA average daily perceived stress when peer mentoring is employed. Inclusion criterion was all SRNAs enrolled in a single 3 year, post-baccalaureate Doctor of Nursing Practice (DNP) NAP at a comprehensive Carnegie research university with Southern Regional Education Board-Level 1 designation. Fifty-six SRNAs were surveyed using a modified version of Dr. Anthony Chipas’ tool for measuring SRNA stress. Thirty-seven surveys were returned for a response rate of 66.1%. The sample group (n=26) consisted of participants who had a peer mentor. These results were compared with the control group (n=11) who did not have a peer mentor. Independent sample t-tests, a Kruskal-Wallis test, and descriptive analysis were performed. An independent sample t-test revealed a statistically significant difference between the mean daily stress levels of the mentored group (M=5.46, SD +1.48) and non-mentored group (M=6.73, SD+1.56), t(35)=2.35, p=0.025. This finding would imply that mentoring is effective at decreasing stress in SRNAs. However, this study lacked an adequate sample size to retain confidence in the result. Although the researcher cannot be confident in the statistical significance of the data, the data supports the hypothesis that peer mentoring may decrease stress levels in SRNAs

Evolution of the Canadian Tax Reform

The passage of the Tax Reform Bill in December 1971 marked the end of an extraordinary decade of inquiry and debate on federal tax reform in Canada. Minor (and some major) changes are still being made, and a further instalment of reform is to be expected in the area of sales taxation. The more controversial issues of tax reform in the field of income taxation have, however, been finally settled, at least for the next few years and probably for a much longer period. While business firms, families and the government wrestle with the complexities of the new system, it is therefore time to sit back and review this remarkable episode in Canadian public finance history. Three main stages can be distinguished in the evolution of the reform to 1971. The first began with the appointment of the Carter Royal Commission in 1962 and ended with the presentation of the Carter Report in February, 1967.\u27 The second began when the Minister of Finance invited public submissions and discussion on the Carter Report and ended after a lively public debate and prolonged government study with the publication of the Benson White Paper in November, 1969.2 The third and final stage was the White Paper process of public and parliamentary discussion of the Benson White Paper ending with the introduction of the detailed legislation in June 1971 and its eventual passage in December 1971.\u27 In the following sections we shall consider the development at each of these three stages in turn

Using Music Therapy to Enhance Social, Speech and Language Skills in One Five Year Old Child with Autism: A Case Study

This descriptive case study examined the effects of using music therapy to enhance engagement, social, and early literacy skills in one 5-year-old boy diagnosed with autism. Video and audiotapes of music therapy sessions, progress notes and reports, and interviews with the boy\u27s parents, special education teacher, and music therapist were qualitatively analyzed for this study. Instructional implications of this study include the recommendation that music therapy services, when used in conjunction with the educational program of autistic children, can be beneficial in helping to facilitate engagement and early literacy goals and objectives. Recommendations for future research in this area include the study of the benefits of music therapy with autistic children beyond the preschools setting with higher-level educational goals