31 research outputs found
Environmental Determinants of Fruit and Vegetable Consumption Among Adults: A Systematic Review
The current ecological approach in health behaviour research recognises that health behaviour needs to be understood in a broad environmental context. This has led to an exponential increase in the number of studies on this topic. It is the aim of this systematic review to summarise the existing empirical evidence pertaining to environmental influences on fruit and vegetable (FV) consumption. The environment was defined as ‘all factors external to the individual’. Scientific databases and reference lists of selected papers were systematically searched for observational studies among adults (18–60 years old), published in English between 1 January 1980 and 31 December 2004, with environmental factor(s) as independent factor(s), and fruit intake, vegetable intake or FV intake combined as one outcome measure as dependent factor(s). Findings showed there was a great diversity in the environmental factors studied, but that the number of replicated studies for each determinant was limited. Most evidence was found for household income, as people with lower household incomes consistently had a lower FV consumption. Married people had higher intakes than those who were single, whereas having children showed mixed results. Good local availability (e.g. access to one's own vegetable garden, having low food insecurity) seemed to exert a positive influence on intake. Regarding the development of interventions, improved opportunities for sufficient FV consumption among low-income households are likely to lead to improved intakes. For all other environmental factors, more replicated studies are required to examine their influence on FV intake
The Influence of Age and Skull Conductivity on Surface and Subdermal Bipolar EEG Leads
Bioelectric source measurements are influenced by the measurement location as well as the conductive
properties of the tissues. Volume conductor effects such as the poorly conducting bones or the moderately conducting skin are known to affect the measurement precision and accuracy of the surface electroencephalography (EEG) measurements. This paper investigates the influence of age via skull conductivity upon surface and subdermal bipolar EEG measurement sensitivity conducted on two realistic head models from the Visible Human Project. Subdermal electrodes (a.k.a. subcutaneous
electrodes) are implanted on the skull beneath the skin, fat, and muscles. We studied the effect of age upon these two electrode types according to the scalp-to-skull conductivity ratios of 5, 8, 15, and 30 : 1. The effects on the measurement sensitivity were studied by means of the half-sensitivity volume (HSV) and the region of interest sensitivity ratio (ROISR). The results indicate that the subdermal implantation notably enhances the precision and accuracy of EEG measurements by a factor of eight compared to the scalp surface measurements. In summary, the evidence indicates that both surface and subdermal EEG measurements benefit better recordings in terms of precision and accuracy on younger patients
Environmental determinants of fruit and vegetable consumption among adults: a systematic review.
The current ecological approach in health behaviour research recognises that health behaviour needs to be understood in a broad environmental context. This has led to an exponential increase in the number of studies on this topic. It is the aim of this systematic review to summarise the existing empirical evidence pertaining to environmental influences on fruit and vegetable (FV) consumption. The environment was defined as 'all factors external to the individual'. Scientific databases and reference lists of selected papers were systematically searched for observational studies among adults (18-60 years old), published in English between 1 January 1980 and 31 December 2004, with environmental factor(s) as independent factor(s), and fruit intake, vegetable intake or FV intake combined as one outcome measure as dependent factor(s). Findings showed there was a great diversity in the environmental factors studied, but that the number of replicated studies for each determinant was limited. Most evidence was found for household income, as people with lower household incomes consistently had a lower FV consumption. Married people had higher intakes than those who were single, whereas having children showed mixed results. Good local availability (e.g. access to one's own vegetable garden, having low food insecurity) seemed to exert a positive influence on intake. Regarding the development of interventions, improved opportunities for sufficient FV consumption among low-income households are likely to lead to improved intakes. For all other environmental factors, more replicated studies are required to examine their influence on FV intake
Environmental determinants of fruit and vegetable consumption among adults: a systematic review
The current ecological approach in health behaviour research recognises that health behaviour needs to be understood in a broad environmental
context. This has led to an exponential increase in the number of studies on this topic. It is the aim of this systematic review to summarise the
existing empirical evidence pertaining to environmental influences on fruit and vegetable (FV) consumption. The environment was defined as ‘all
factors external to the individual’. Scientific databases and reference lists of selected papers were systematically searched for observational studies
among adults (18–60 years old), published in English between 1 January 1980 and 31 December 2004, with environmental factor(s) as independent factor(s), and fruit intake, vegetable intake or FV intake combined as one outcome measure as dependent factor(s). Findings showed there was
a great diversity in the environmental factors studied, but that the number of replicated studies for each determinant was limited. Most evidence
was found for household income, as people with lower household incomes consistently had a lower FV consumption. Married people had higher
intakes than those who were single, whereas having children showed mixed results. Good local availability (e.g. access to one’s own vegetable
garden, having low food insecurity) seemed to exert a positive influence on intake. Regarding the development of interventions, improved opportunities for sufficient FV consumption among low-income households are likely to lead to improved intakes. For all other environmental factors,
more replicated studies are required to examine their influence on FV intake
EEG/MEG Source Imaging: Methods, Challenges, and Open Issues
We present the four key areas of research—preprocessing, the volume conductor, the forward problem, and the inverse problem—that affect the performance of EEG and MEG source
imaging. In each key area we identify prominent approaches and methodologies that have open
issues warranting further investigation within the community, challenges associated with certain
techniques, and algorithms necessitating clarification of their implications. More than providing
definitive answers we aim to identify important open issues in the quest of source localization
The influence of tissue conductivity and head geometry on EEG measurement sensitivity distributions
Electrical neuroimaging is a contemporary functional imaging method that evolves electroencephalography (EEG) beyond traditional signal analysis. It exploits the millisecond temporal resolution of EEG and integrates it with its spatial resolution, which is mapped according to the measurement sensitivity distribution of the measurement leads. This thesis assesses the EEG measurement sensitivity distribution according to the influence of tissue conductivities, electrode placement, electrode type, and geometries upon volume conductor head models.
The conductivity of the skull is correlated with the age of the patient, recognizing that juveniles have higher spatial resolution than adults. Surface electrodes are compared with subdermal electrodes and are found to be non-interchangeable because the subdermal electrodes measure electric activity from one-eighth the volume of their surface-electrode counterparts. More accurate geometrical definitions naturally yield more precise forward and inverse calculations; however, a stochastically deformable generic head model based on anthropometric data addresses the void in imaged and segmented heads of different ages, genders and head shapes. Comprehensively, the investigation of these three key areas improves the knowledge of the EEG measurement sensitivity distributions, which will conceivably translate into clinical improvements in the diagnostics of brain functionality
The influence of tissue conductivity and head geometry on EEG measurement sensitivity distributions
Electrical neuroimaging is a contemporary functional imaging method that evolves electroencephalography (EEG) beyond traditional signal analysis. It exploits the millisecond temporal resolution of EEG and integrates it with its spatial resolution, which is mapped according to the measurement sensitivity distribution of the measurement leads. This thesis assesses the EEG measurement sensitivity distribution according to the influence of tissue conductivities, electrode placement, electrode type, and geometries upon volume conductor head models.
The conductivity of the skull is correlated with the age of the patient, recognizing that juveniles have higher spatial resolution than adults. Surface electrodes are compared with subdermal electrodes and are found to be non-interchangeable because the subdermal electrodes measure electric activity from one-eighth the volume of their surface-electrode counterparts. More accurate geometrical definitions naturally yield more precise forward and inverse calculations; however, a stochastically deformable generic head model based on anthropometric data addresses the void in imaged and segmented heads of different ages, genders and head shapes. Comprehensively, the investigation of these three key areas improves the knowledge of the EEG measurement sensitivity distributions, which will conceivably translate into clinical improvements in the diagnostics of brain functionality
Image Quality Evaluation in Clinical Research: A Case Study on Brain and Cardiac MRI Images in Multi-Center Clinical Trials
Magnetic resonance imaging (MRI) system images are important components in the development of drugs because it can reveal the underlying pathology in diseases. Unfortunately, the processes of image acquisition, storage, transmission, processing, and analysis can influence image quality with the risk of compromising the reliability of MRI-based data. Therefore, it is necessary to monitor image quality throughout the different stages of the imaging workflow. This report describes a new approach to evaluate the quality of an MRI slice in multi-center clinical trials. The design philosophy assumes that an MRI slice, such as all natural images, possess statistical properties that can describe different levels of contrast degradation. A unique set of pixel configuration is assigned to each possible level of contrast-distorted MRI slice. Invocation of the central limit theorem results in two separate Gaussian distributions. The central limit theorem says that the mean and standard deviation of pixel configuration assigned to each possible level of contrast degradation will follow a normal distribution. The mean of each normal distribution corresponds to the mean and standard deviation of the underlying ideal image. Quality prediction processes for a test image can be summarized into four steps. The first step extracts local contrast feature image from the test image. The second step computes the mean and standard deviation of the feature image. The third step separately standardizes each normal distribution using the mean and standard deviation computed from the feature image. This gives two separate z-scores. The fourth step predicts the lightness contrast quality score and the texture contrast quality score from cumulative distribution function of the appropriate normal distribution. The proposed method was evaluated objectively on brain and cardiac MRI volume data using four different types and levels of degradation. The four types of degradation are Rician noise, circu...acceptedVersion© 2018 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works