1,797 research outputs found
Chk1 activity is required for BAK multimerization in association with PUMA during mitochondrial apoptosis
The Effect of Biculturalism on Depression in Northern Plains Native American College Students
The primary purpose of this study was to examine the effect of biculturalism on depression in a propsed sample of 52 Northern Plains Native American College students (32 female, 20 male). This study tested the applicability of the Orthogonal Theory of Biculturalism (Oetting and Beauvais, 1992). Subjects completed the Northern Plains Biculturalism scale (NPBI) and the Beck Depression Inventory-Second edition (BDI-II). A descriptive analysis, Pearson product moment correlational analysis, independent t-tests, and multiple regression analysis were performed. The multiple regression utilized the two-culture orientation subscales of the NPBI as predictor variables and the total score of the BDI-II as outcome variables. It was predicted that higher scores on both NPBI subscales (Bicultural competence) predicted lower scores on the BDI-II. No significant results were found in this study
The Impact Of Biculturalism On Human Learned Helplessness With Northern Plains Native Americans
This study investigated the effects of participant ethnicity, research ethnicity, and either failure, success, or neural feedback on performance on letter anagram tasks. The failure feedback represented a standard learned helplessness paradigm with the dependent measures focused on the interferences and behavior of he participants in response to feedback from either a Native American or European American researcher. A total of 55 Native Americans and 73 European Americans were assigned randomly to one of three feedback conditions (success, failure, neutral) conducted by a study blind examiner of either American Indian or Caucasian ethnicity and appearance. Participant level of biculturalism was assessed using the Northern Plains Biculturalism Inventory (NPBI), a 30 item questionnaire which assesses the degree of cultural competence on two orthogonally related cultural dimensions. Learned helplessness effects were inferred for groups as a function of anagrams completed as well as through the Concept Formation Task Questionnaire (CFTQ) measure of individual participant self-perceptions regarding the adequacy of their performance. Feedback was manipulated by the examiners with random assignment of participants to either a 100% Failure group, 100% Success condition, of accurate and neutral feedback. Additional questionnaire items were used to ethnicity. Native American participants did complete the fewest anagrams in the failure condition as predicted when European American examiners provided the feedback. Native American participant confidence and satisfaction in their performance on the anagram task (CFTQ) was curiously lower when the feedback came back from a European American examiner as opposed to someone from the same ethnicity. It was also hypothesized in this study that American Indian subjects exhibiting higher levels of Traditional or Marginal cultural orientation would show greater frustration and learned helplessness in the Failure group than their more Assimilated or Bicultural peers, as well as the Caucasian subjects. Trends were shown suggesting resiliency to these effects among American Indian participants with Bicultural or Assimilated, as opposed to Traditional or Marginal cultural orientations
The Impact Of Biculturalism On Human Learned Helplessness With Northern Plains Native Americans
This study investigated the effects of participant ethnicity, research ethnicity, and either failure, success, or neural feedback on performance on letter anagram tasks. The failure feedback represented a standard learned helplessness paradigm with the dependent measures focused on the interferences and behavior of he participants in response to feedback from either a Native American or European American researcher. A total of 55 Native Americans and 73 European Americans were assigned randomly to one of three feedback conditions (success, failure, neutral) conducted by a study blind examiner of either American Indian or Caucasian ethnicity and appearance. Participant level of biculturalism was assessed using the Northern Plains Biculturalism Inventory (NPBI), a 30 item questionnaire which assesses the degree of cultural competence on two orthogonally related cultural dimensions. Learned helplessness effects were inferred for groups as a function of anagrams completed as well as through the Concept Formation Task Questionnaire (CFTQ) measure of individual participant self-perceptions regarding the adequacy of their performance. Feedback was manipulated by the examiners with random assignment of participants to either a 100% Failure group, 100% Success condition, of accurate and neutral feedback. Additional questionnaire items were used to ethnicity. Native American participants did complete the fewest anagrams in the failure condition as predicted when European American examiners provided the feedback. Native American participant confidence and satisfaction in their performance on the anagram task (CFTQ) was curiously lower when the feedback came back from a European American examiner as opposed to someone from the same ethnicity. It was also hypothesized in this study that American Indian subjects exhibiting higher levels of Traditional or Marginal cultural orientation would show greater frustration and learned helplessness in the Failure group than their more Assimilated or Bicultural peers, as well as the Caucasian subjects. Trends were shown suggesting resiliency to these effects among American Indian participants with Bicultural or Assimilated, as opposed to Traditional or Marginal cultural orientations
A New Approach to Intensity-Dependent Normalization of Two-Channel Microarrays
A two-channel microarray measures the relative expression levels of thousands of genes from a pair of biological samples. In order to reliably compare gene expression levels between and within arrays, it is necessary to remove systematic errors that distort the biological signal of interest. The standard for accomplishing this is smoothing MA-plots to remove intensity-dependent dye bias and array-specific effects. However, MA methods require strong assumptions. We review these assumptions and derive several practical scenarios in which they fail. The dye-swap normalization method has been much less frequently used because it requires two arrays per pair of samples. We show that a dye-swap is accurate under general assumptions, even under intensity-dependent dye bias, and that a dye-swap provides the minimal information required for removing dye bias from a pair of samples in general. Based on a flexible model of the relationship between mRNA amount and single channel fluorescence intensity, we demonstrate the general applicability of a dye-swap approach. We then propose a common array dye-swap (CADS) method for the normalization of two-channel microarrays. We show that CADS removes both dye-bias and array-specific effects, and preserves the true differential expression signal for every gene. Finally, we discuss some possible extensions of CADS that circumvent the need to use two arrays per pair of samples
Optimal Feature Selection for Nearest Centroid Classifiers, With Applications to Gene Expression Microarrays
Nearest centroid classifiers have recently been successfully employed in high-dimensional applications. A necessary step when building a classifier for high-dimensional data is feature selection. Feature selection is typically carried out by computing univariate statistics for each feature individually, without consideration for how a subset of features performs as a whole. For subsets of a given size, we characterize the optimal choice of features, corresponding to those yielding the smallest misclassification rate. Furthermore, we propose an algorithm for estimating this optimal subset in practice. Finally, we investigate the applicability of shrinkage ideas to nearest centroid classifiers. We use gene-expression microarrays for our illustrative examples, demonstrating that our proposed algorithms can improve the performance of a nearest centroid classifier
Normalization of two-channel microarrays accounting for experimental design and intensity-dependent relationships
eCADS is a new method for multiple array normalization of two-channel microarrays that takes into account general experimental designs and intensity-dependent relationships and allows for a more efficient dye-swap design that requires only one array per sample pair
Thiothymidine plus low-dose UVA kills hyperproliferativehuman skin cells independently of their human papilloma virus status
The thymidine analogue 4-thiothymidine (S4TdR) is a photosensitizer for UVA radiation. The UV absorbance spectrum of S4TdR and its incorporation into DNA suggests that it might act synergistically with nonlethal doses of UVA to selectively kill hyperproliferative or cancerous skin cells. We show here that nontoxic concentrations of S4TdR combine with nonlethal doses of UVA to kill proliferating cultured skin cells. Established cell lines with a high fraction of proliferating cells were more sensitive than primary keratinocytes or fibroblasts to apoptosis induction by S4TdR/UVA. Although S4TdR plus UVA treatment induces stabilization of p53, cell death, as measured by apoptosis or clonal survival, occurs to a similar extent in both p53 wild-type and p53-null backgrounds. Furthermore, different types of human papilloma virus E6 proteins, which protect against UVB-induced apoptosis, have little effect on killing by S4TdR/UVA. S4TdR/UVA offers a possible therapeutic intervention strategy that seems to be applicable to human papilloma virus–associated skin lesions
A lateral protrusion latticework connects neuroepithelial cells and is regulated during neurogenesis
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