Low Frequency Noise in Randomly Stimulated Asymmetric Oscillators

A new mechanism of low frequency (1/f-like) noise generation is described and analyzed. It is attributed to higher frequency asymmetric resonance modes, which are stimulated by a random factor, e.g. due to thermal excitation. One-dimensional models of bi-harmonic and non-linear asymmetric oscillators are presented to prove the concept, and a method of detecting the effect is developed. The method is then applied to experimental data, in order to show that the effect exists in magnetoresistive readers

Including Ethics in the Study of Educational Leadership

This article offers reasons why ethics should be included within leadership preparation and suggestions for infusing it in leadership education classes. The authors argue that a framework of making ethical decisions, overviews of codes of conduct, and examinations of case studies of ethical and unethical behaviors become intentional components of leadership education curricula

Fourth and Fifth Grade Departmentalization: A Transition to Middle School

The difficulties involved in the transition for students leaving elementary school, where there typically exists little departmentalization, to the middle school, where departmentalization is the primary structure, have often been noted by scholars. While some studies cited in this work indicated a decrease in student achievement with the implementation of departmentalization, this approach should not be categorically rejected. In this regard, this study examines how elementary students can begin to be better prepared in fourth and fifth grades to enter the departmentalization system

Ooligan Grease: A Nutritious Fat Used by Native People of Coastal British

ABSTRACT.-Marine fat, derived from several sources, was formerly used to great extent by Northwest Coast Indians as a flavor enhancer of many foods as well as for medicinal and ceremonial purposes. The most prominent source of food fat used by British Columbia native people has been from the ooligan (Thaleichthys pacificus Richardson, Osmeridae) a small fish which is harvested in bulk in early spring, allowed to ripen in large bins, and then rendered to give a pungent, golden, thick oil called "ooUgan grease". Samples from five preparations of this fat were made in 1981 from the Nuxalk Community of Bella Coola, B.C. and several nutrient analyses were done. Fatty acids, expressed as mean and range of percent methyl esters were: saturated at 32.2 (30-33), monounsaturated at 64.5 (63-66), and polyunsaturated at 0.9 (0.8-

Age-related macular degeneration: choroidal ischaemia?

Aim: Our aim is to use ultrasound to non-invasively detect differences in choroidal microarchitecture possibly related to ischaemia among normal eyes and those with wet and dry age-related macular degeneration (AMD). Design Prospective case series of subjects with dry AMD, wet AMD and age-matched controls. Methods: Digitized 20 MHz B-scan radiofrequency ultrasound data of the region of the macula were segmented to extract the signal from the retina and choroid. This signal was processed by a wavelet transform, and statistical modelling was applied to the wavelet coefficients to examine differences among dry, wet and non-AMD eyes. Receiver operating characteristic (ROC) analysis was used to evaluate a multivariate classifier. Results: In the 69 eyes of 52 patients, 18 did not have AMD, 23 had dry AMD and 28 had wet AMD. Multivariate models showed statistically significant differences between groups. Multiclass ROC analysis of the best model showed an excellent volume-under-curve of 0.892±0.17. The classifier is consistent with ischaemia in dry AMD. Conclusions: Wavelet augmented ultrasound is sensitive to the organisational elements of choroidal microarchitecture relating to scatter and fluid tissue boundaries such as seen in ischaemia and inflammation, allowing statistically significant differentiation of dry, wet and non-AMD eyes. This study further supports the association of ischaemia with dry AMD and provides a rationale for treating dry AMD with pharmacological agents to increase choroidal perfusion

Measurement of choroidal perfusion and thickness following systemic sildenafil (Viagra)

Purpose: To demonstrate anatomic and physiologic changes in the human choroid following systemic sildenafil citrate (Viagra) using enhanced depth imaging spectral domain–optical coherence tomography (EDI-OCT) and swept-scan high-frequency digital ultrasound. Methods: Seven healthy male subjects (mean age 32.7 years) were evaluated at baseline and 2 hr after ingesting 50 mg of sildenafil. Swept-scan high-frequency digital ultrasound and EDI-OCT were utilized to measure choroidal perfusion and thickness, respectively. Results were read by masked observers. The Wilcoxon signed-rank test and t-test were used to analyse differences in choroidal flow and thickness at baseline and 2 hr after ingestion of sildenafil. Results: Two hours following sildenafil, increased choroidal perfusion was observed in 11 of 12 eyes measured by swept-scan high-frequency digital ultrasound. The mean increase was 3.46 (±2.00) times baseline with a range of 0.47–7.80 times baseline (p = 0.004). Increased choroidal thickness was observed in 12 of 12 eyes measured with EDI-OCT. The average choroidal thickness increased by 11.6% temporal to the fovea, 9.3% nasal to the fovea and 10.7% underneath the fovea (p < 0.001 for all values). Conclusions: Choroidal perfusion and thickness both increase in response to systemic sildenafil. These changes could secondarily affect retinal function, explain previously reported clinical symptoms and potentially be a useful adjunct for treatment of ocular diseases that would benefit from increased choroidal blood flow

Aboriginal Food Security in Northern Canada: An Assessment of the State of Knowledge

As the world’s population increases, as global markets become more interconnected, and as the effects of climate change become clearer, the issue of food insecurity is gaining traction at local, national, and international levels. The recent global economic crisis and increased food prices have drawn attention to the urgent situation of the world’s 870 million chronically undernourished people who face the number one worldwide risk to health: hunger and malnutrition. Although about 75% of the world’s undernourished people live in low-income, rural regions of developing countries, hunger is also an issue in Canada. In 2011, 1.6 million Canadian households, or slightly more than 12%, experienced some level of food insecurity. About one in eight households are affected, including 3.9 million individuals. Of these, 1.1 million are children. Food insecurity presents a particularly serious and growing challenge in Canada’s northern and remote Aboriginal communities (see Figure 1). Evidence from a variety of sources concludes that food insecurity among northern Aboriginal peoples is a problem that requires urgent attention to address and mitigate the serious impacts it has on health and well-being. Results from the 2007–2008 International Polar Year Inuit Health Survey indicate that Nunavut has the highest documented rate of food insecurity for any Indigenous population living in a developed country. According to estimates from the 2011 Canadian Community Health Survey (CCHS), off-reserve Aboriginal households across Canada experience food insecurity at a rate that is more than double that of all Canadian households (27%). Recent data indicate that Canadian households with children have a higher prevalence of food insecurity than households without children, and preliminary evidence indicates that more women than men are affected