Ethnicity and Health: An Analysis of Physical Health Differences across Twenty-one Ethnocultural Groups in Canada

The study of health differences across a wide-range of ethnic, racial, and cultural groups has received relatively little attention in the literature. Twenty-one ethnocultural groups are examined in the current study, providing one of the most comprehensive analyses to-date on ethnicity and physical health in Canada. Two specific research questions are addressed. First, what is the extent of ethnocultural-based health inequalities in Canada? Second, do ethnocultural differences in health reflect differences in social structural and health-related behavioural environments? These questions are analyzed using the master datafile of the 2000/2001 Canadian Community Health Survey (n=129,588). Three global measures of physical health are used: self-rated health, functional health, and activity restriction. The results show that certain ethnic and cultural groups experience higher health status compared to other ethnocultural groups. Social structural (i.e., socio-demographic and SES factors) and behavioural (alcohol and cigarette consumption, diet/nutrition, and exercise) control variables are also introduced to determine if these factors mediate the relationship between ethnicity/race and health. These findings show that health differences between ethnic and racial groups are partly attributable to structural and behavioural factors. They also show that the mediating effects of these variables vary across ethnocultural groups, and that social structural factors are generally more important than behavioural ones in explaining ethnocultural-based differences in health. The implications of the study findings for future research on ethnicity and health and for health care policies are discussed.ethnicity, race, self-rated health, functional health, social structure, lifestyle

High-gain AlGaAs/GaAs double heterojunction Darlington phototransistors for optical neural networks

High-gain MOCVD-grown (metal-organic chemical vapor deposition) AlGaAs/GaAs/AlGaAs n-p-n double heterojunction bipolar transistors (DHBTs) and Darlington phototransistor pairs are provided for use in optical neural networks and other optoelectronic integrated circuit applications. The reduced base doping level used results in effective blockage of Zn out-diffusion, enabling a current gain of 500, higher than most previously reported values for Zn-diffused-base DHBTs. Darlington phototransitor pairs of this material can achieve a current gain of over 6000, which satisfies the gain requirement for optical neural network designs, which advantageously may employ neurons comprising the Darlington phototransistor pairs in series with a light source

GaAs-based optoelectronic neurons

An integrated, optoelectronic, variable thresholding neuron implemented monolithically in GaAs integrated circuit and exhibiting high differential optical gain and low power consumption is presented. Two alternative embodiments each comprise an LED monolithically integrated with a detector and two transistors. One of the transistors is responsive to a bias voltage applied to its gate for varying the threshold of the neuron. One embodiment is implemented as an LED monolithically integrated with a double heterojunction bipolar phototransistor (detector) and two metal semiconductor field effect transistors (MESFET's) on a single GaAs substrate and another embodiment is implemented as an LED monolithically integrated with three MESFET's (one of which is an optical FET detector) on a single GaAs substrate. The first noted embodiment exhibits a differential optical gain of 6 and an optical switching energy of 10 pJ. The second embodiment has a differential optical gain of 80 and an optical switching energy of 38 pJ. Power consumption is 2.4 and 1.8 mW, respectively. Input 'light' power needed to turn on the LED is 2 micro-W and 54 nW, respectively. In both embodiments the detector is in series with a biasing MESFET and saturates the other MESFET upon detecting light above a threshold level. The saturated MESFET turns on the LED. Voltage applied to the biasing MESFET gate controls the threshold

A SAMPLE SELECTION APPROACH TO CENSORED DEMAND SYSTEMS

A censored demand system estimator is proposed by extending the sample selection model of Heckman. Censoring is governed by a selection mechanism which avoids the restricitve Tobit parameterization. Results of application to household consumption of beverages suggest the estimator produces slightly different elasticity estimates from the Tobit estimator. Demands for beverages are nearly unitary elastic, and net substitution is an obvious pattern.beverages, censoring, sample selection, Translog demand system, Demand and Price Analysis,

GaAs optoelectronic neuron arrays

A simple optoelectronic circuit integrated monolithically in GaAs to implement sigmoidal neuron responses is presented. The circuit integrates a light-emitting diode with one or two transistors and one or two photodetectors. The design considerations for building arrays with densities of up to 10^4 cm^-2 are discussed

Consumer Knowledge, Food Label Use and Grain Consumption

Responding to mounting evidence of the association between whole-grain consumption and a reduced risk of heart problems and other diseases as well as body weight maintenance, the U.S. Government has strongly encouraged its citizens to increase consumption of whole grains. However, compared against the 2005 Federal dietary recommendations, in 1994-96 only 6 percent of Americans met the current recommended whole-grain consumption. To narrow this huge gap between actual and recommended consumption of whole grains, an effective nutrition education campaign is needed. A demand system with two censored consumption equations and two endogenous knowledge and attitude variables is estimated to investigate the factors that affect the consumption of whole and refined grains. The results can be used to help develop an effective education campaign in promoting consumption of whole grains in Americans' diets.Consumer/Household Economics,

Topology optimization of freeform large-area metasurfaces

We demonstrate optimization of optical metasurfaces over $10^5$--$10^6$ degrees of freedom in two and three dimensions, 100--1000+ wavelengths ($\lambda$) in diameter, with 100+ parameters per $\lambda^2$. In particular, we show how topology optimization, with one degree of freedom per high-resolution "pixel," can be extended to large areas with the help of a locally periodic approximation that was previously only used for a few parameters per $\lambda^2$. In this way, we can computationally discover completely unexpected metasurface designs for challenging multi-frequency, multi-angle problems, including designs for fully coupled multi-layer structures with arbitrary per-layer patterns. Unlike typical metasurface designs based on subwavelength unit cells, our approach can discover both sub- and supra-wavelength patterns and can obtain both the near and far fields

Ethnic Differences in Health: Does Immigration Status Matter?

This study examines health differences between first-generation immigrant and Canadian-born persons who share the same the ethnocultural origin, and the extent to which such differences reflect social structural and health-related behavioural contexts. Data from the 2000/2001 Canadian Community Health Survey show that first generation immigrants of Black and French race/ethnicity tend to have better health than their Canadian-born counterparts, while the opposite is true for those of South Asian, Chinese, and south and east European and Jewish origins. West Asians and Arabs and other Asian groups are advantaged in health regardless of country of birth. Health differences between ethnic foreign- and Canadian-born persons generally converge after adjusting for socio-demographic, SES, and lifestyle factors. Implications for health care policy and program development are discussed.self-rated health; functional health; ethnicity; race; immigration