title: Studies of the coefficient of variation of the magnitude of EEG signals

authors: Round, W. Howell

subjects: EEG

abstract: An analysis of the variation in magnitude of EEG signals in various frequency bands of anesthetized patients and normal sleeping volunteers was carried out. The coefficient of variation (CoV), i.e. the standard deviation/mean, within 10 second epochs was found to be quite constant throughout the whole of the EEG recordings and was typically about 0.46. This was found to be the case for both the patients and the volunteers. Histograms of the magnitudes indicated that the magnitudes are distributed as f(x)=βxe(-αx2) functions. However a CoV of 0.46 is consistent with f(x)=βxe(-αx3) functions. The non-stationary nature of the EEG is such that it is likely that while over short periods the EEG magnitudes are distributed as f(x)=βxe(-αx3) functions, variations of α over time mean that in the long term the EEG magnitudes are distributed as f(x)=βxe(-αx2) functions.

text: Studies of the coefficient of variation of the magnitude of EEG signals An analysis of the variation in magnitude of EEG signals in various frequency bands of anesthetized patients and normal sleeping volunteers was carried out. The coefficient of variation (CoV), i.e. the standard deviation/mean, within 10 second epochs was found to be quite constant throughout the whole of the EEG recordings and was typically about 0.46. This was found to be the case for both the patients and the volunteers. Histograms of the magnitudes indicated that the magnitudes are distributed as f(x)=βxe(-αx2) functions. However a CoV of 0.46 is consistent with f(x)=βxe(-αx3) functions. The non-stationary nature of the EEG is such that it is likely that while over short periods the EEG magnitudes are distributed as f(x)=βxe(-αx3) functions, variations of α over time mean that in the long term the EEG magnitudes are distributed as f(x)=βxe(-αx2) functions.

year: 2001

title: A supercapacitor technique for efficiency improvement in linear regulators

authors: Kularatna, Nihal

subjects: engineering

abstract: Paper describes a novel supercapacitor based approach to recover the wasted energy in linear regulators. In this US patent pending technique, a single supercapacitor or an array of supercapacitors could be coupled with a linear series or shunt regulator, where the supercapacitors are charged by the input current of the regulator. This supercapacitor technique, by maintaining the dropout voltage limit before a new capacitor is placed in the series path, recovers the energy and does not use the supercapacitors for voltage conversion. Average efficiency of the overall circuit is improved by a significant amount, while maintaining the useful hall marks of a linear regulator. An example of a 12 to 5 volt proof of concept circuit is detailed with an overall efficiency improvement from 42% to over 78%. The technique is versatile, and, can be developed further to compete with the higher efficiency switching power supplies.

text: A supercapacitor technique for efficiency improvement in linear regulators Paper describes a novel supercapacitor based approach to recover the wasted energy in linear regulators. In this US patent pending technique, a single supercapacitor or an array of supercapacitors could be coupled with a linear series or shunt regulator, where the supercapacitors are charged by the input current of the regulator. This supercapacitor technique, by maintaining the dropout voltage limit before a new capacitor is placed in the series path, recovers the energy and does not use the supercapacitors for voltage conversion. Average efficiency of the overall circuit is improved by a significant amount, while maintaining the useful hall marks of a linear regulator. An example of a 12 to 5 volt proof of concept circuit is detailed with an overall efficiency improvement from 42% to over 78%. The technique is versatile, and, can be developed further to compete with the higher efficiency switching power supplies.

year: 2009

title: Māori men and the indirect procurement and sharing of prescription medications

authors: Hodgetts, Darrin

subjects: Māori men

abstract: Māori men have higher rates of many diseases and lower life expectancy than other population groups in New Zealand. The general consensus is that these health inequalities are due to the inequitable distribution of the social determinants of health; for example, education, employment, income and housing, and were largely driven by colonization and the social and economic marginalization of Māori. Health care factors, including reluctance to consult doctors or late presentation, are part of this equation, but do not fully explain the disparities in health between Māori men and other population groups. As part of our ongoing work in this area, we draw on a focus group discussion with seven Māori community health workers to provide a preliminary analysis of how some Māori people access and use medications. Particular attention is given to the emergent practice of Māori women presenting to general practitioners (GPs) with proxy symptoms to obtain medications for their male partners. This practice exemplifies a range of strategies that some whānau (family) have developed to navigate the health system and overcome the reluctance of some men to engage with the medical profession. The practice raises issues relating to the nature of “primary” and “whānau” care, accessibility of medical services and medications, adherence to medication regimes and the dynamics of doctor–patient relations.

text: Māori men and the indirect procurement and sharing of prescription medications Māori men have higher rates of many diseases and lower life expectancy than other population groups in New Zealand. The general consensus is that these health inequalities are due to the inequitable distribution of the social determinants of health; for example, education, employment, income and housing, and were largely driven by colonization and the social and economic marginalization of Māori. Health care factors, including reluctance to consult doctors or late presentation, are part of this equation, but do not fully explain the disparities in health between Māori men and other population groups. As part of our ongoing work in this area, we draw on a focus group discussion with seven Māori community health workers to provide a preliminary analysis of how some Māori people access and use medications. Particular attention is given to the emergent practice of Māori women presenting to general practitioners (GPs) with proxy symptoms to obtain medications for their male partners. This practice exemplifies a range of strategies that some whānau (family) have developed to navigate the health system and overcome the reluctance of some men to engage with the medical profession. The practice raises issues relating to the nature of “primary” and “whānau” care, accessibility of medical services and medications, adherence to medication regimes and the dynamics of doctor–patient relations.

year: 2011