Treatment Designs (treatment + design)

Distribution by Scientific Domains


Selected Abstracts


Levene Tests of Homogeneity of Variance for General Block and Treatment Designs

BIOMETRICS, Issue 1 2002
Michael E. O'Neill
Summary. This article develops a weighted least squares version of Levene's test of homogeneity of variance for a general design, available both for univariate and multivariate situations. When the design is balanced, the univariate and two common multivariate test statistics turn out to be proportional to the corresponding ordinary least squares test statistics obtained from an analysis of variance of the absolute values of the standardized mean-based residuals from the original analysis of the data. The constant of proportionality is simply a design-dependent multiplier (which does not necessarily tend to unity). Explicit results are presented for randomized block and Latin square designs and are illustrated for factorial treatment designs and split-plot experiments. The distribution of the univariate test statistic is close to a standard F -distribution, although it can be slightly underdispersed. For a complex design, the test assesses homogeneity of variance across blocks, treatments, or treatment factors and offers an objective interpretation of residual plots. [source]


Protection of hematopoietic cells from O6 -alkylation damage by O6 -methylguanine DNA methyltransferase gene transfer: studies with different O6 -alkylating agents and retroviral backbones

EUROPEAN JOURNAL OF HAEMATOLOGY, Issue 1 2001
Michael Jansen
Abstract: Overexpression of O6 -methylguanine DNA methyltransferase (MGMT) can protect hematopoietic cells from O6 -alkylation damage. To identify possible clinical applications of this technology we compared the effect of MGMT gene transfer on the hematotoxicity induced by different O6 -alkylating agents in clinical use: the chloroethylnitrosoureas ACNU, BCNU, CCNU and the tetrazine derivative temozolomide. In addition, various retroviral vectors expressing the MGMT-cDNA were investigated to identify optimal viral backbones for hematoprotection by MGMT expression. Protection from ACNU, BCNU, CCNU or temozolomide toxicity was evaluated utilizing a Moloney murine leukemia virus-based retroviral vector (N2/Zip-PGK-MGMT) to transduce primary murine bone marrow cells. Increased resistance in murine colony-forming units (CFU) was demonstrated for all four drugs. In comparison to mock-transduced controls, after transduction with N2/Zip-PGK-MGMT the IC50 for CFU increased on average 4.7-fold for ACNU, 2.5-fold for BCNU, 6.3-fold for CCNU and 1.5-fold for temozolomide. To study the effect of the retroviral backbone on hematoprotection various vectors expressing the human MGMT-cDNA from a murine embryonic sarcoma virus LTR (MSCV-MGMT) or a hybrid spleen focus-forming/murine embryonic sarcoma virus LTR (SF1-MGMT) were compared with the N2/Zip-PGK-MGMT vector. While all vectors increased resistance of transduced human CFU to ACNU, the SF1-MGMT construct was most efficient especially at high ACNU concentrations (8,12 g/ml). Similar results were obtained for protection of murine high-proliferative-potential colony-forming cells. These data may help to optimize treatment design and retroviral constructs in future clinical studies aiming at hematoprotection by MGMT gene transfer. [source]


Treatment Technology: "Common Knowledge" getting in the way of successful treatment design and implementation

GROUND WATER MONITORING & REMEDIATION, Issue 1 2005
EvanK.
First page of article [source]


The Effect of Later Life Parental Divorce on Adult-Child/Older-Parent Solidarity: A Test of the Buffering Hypothesis,

JOURNAL OF APPLIED SOCIAL PSYCHOLOGY, Issue 6 2003
Paul A. Nakonezny
The present study examined the effect of later life parental divorce on solidarity in the relationship between the adult child and older parent. This examination was achieved by testing the buffering hypothesis. A cross-sectional quasiexperimental pre-post treatment design was used (Cook & Campbell, 1979), with retrospective pretests and data from 100 adult-child/older-parent dyads. The ANOVA results show that the mother/adult-child relationship with a higher degree of predivorce solidarity responded to later life parental divorce with less disruption of affectional solidarity and associational solidarity than those with a lower degree of predivorce solidarity. Thus, the current research provides modest evidence (for the mother/adult-child relationship) to support the buffering hypothesis. We found no evidence of a buffering effect for the father-child relationship. [source]


Conceptual and Design Essentials for Evaluating Mechanisms of Change

ALCOHOLISM, Issue 2007
Matthew K. Nock
Background:, Considerable progress has been made toward the development of evidence-based treatments for a wide range of psychological disorders; however, little is known about the mechanisms through which these treatments actually lead to clinical change. Although the use of traditional randomized controlled treatment designs and tests of statistical mediation have significantly advanced understanding of psychological treatments, they are insufficient to test mechanisms of change. Method:, This article outlines the conceptual and methodological requirements for evaluating mechanisms of change, highlights the importance of such a focus, and offers specific recommendations for research aimed at elucidating change mechanisms. Results and Conclusions:, Conceptualizing and conducting studies that test mechanisms of change requires substantial modifications to traditional research designs, but doing so will significantly enhance scientific understanding as well as the efficiency and effectiveness of clinical interventions. [source]


An investigation of listening and listening-while-reading accommodations on reading comprehension levels and rates in students with emotional disorders

PSYCHOLOGY IN THE SCHOOLS, Issue 1 2005
Andrea D. Hale
Researchers used alternating treatment designs to investigate the effects of listening-while-reading (LWR) and listening interventions on comprehension levels and rates in four middle school students with emotional disorders. During LWR, students were instructed to read passages silently along with experimenters. During the listening condition, we did not give students a printed copy of the passage but merely instructed them to listen as an experimenter read the passages aloud. The control condition consisted of students reading passages silently. After each condition, students answered 10 comprehension questions without referring back to the printed passage. Although neither intervention resulted in comprehension levels consistently superior to those of the silent reading control condition, LWR and listening resulted in higher rates of comprehension than the silent reading control condition across all four students. However, listening appeared to improve reading comprehension rates in only two students. These results suggest that LWR may be an efficient procedure for enhancing comprehension across content areas with groups of students who have heterogeneous reading skills. The discussion focuses on future applied research with students with disabilities. 2005 Wiley Periodicals, Inc. Psychol Schs 42: 39,51, 2005. [source]


A further comparison of external control and problem-solving interventions to teach social skills to adults with intellectual disabilities

BEHAVIORAL INTERVENTIONS, Issue 3 2004
Mark F. O'Reilly
We compared the effectiveness of a problem-solving and an external control intervention to teach social skills to two adults with mild intellectual disabilities. Each participant received the problem-solving intervention with one social skill and the external control intervention with another social skill. The comparative effectiveness of the social skill training protocols was evaluated using individual participant alternating treatment designs. Overall, there seemed to be little difference between the interventions in terms of acquisition, generalization, or maintenance of social skills with either participant. Limitations of the current study and issues for future research are discussed. Copyright 2004 John Wiley & Sons, Ltd. [source]


Levene Tests of Homogeneity of Variance for General Block and Treatment Designs

BIOMETRICS, Issue 1 2002
Michael E. O'Neill
Summary. This article develops a weighted least squares version of Levene's test of homogeneity of variance for a general design, available both for univariate and multivariate situations. When the design is balanced, the univariate and two common multivariate test statistics turn out to be proportional to the corresponding ordinary least squares test statistics obtained from an analysis of variance of the absolute values of the standardized mean-based residuals from the original analysis of the data. The constant of proportionality is simply a design-dependent multiplier (which does not necessarily tend to unity). Explicit results are presented for randomized block and Latin square designs and are illustrated for factorial treatment designs and split-plot experiments. The distribution of the univariate test statistic is close to a standard F -distribution, although it can be slightly underdispersed. For a complex design, the test assesses homogeneity of variance across blocks, treatments, or treatment factors and offers an objective interpretation of residual plots. [source]


The effect of providing choices on skill acquisition and competing behavior of children with autism during discrete trial instruction

BEHAVIORAL INTERVENTIONS, Issue 1 2002
Bobby Newman
Discrete trial instruction was carried out for three students with autism. An alternating treatments design was implemented. In one condition, teachers chose the reinforcers to be used and the order in which programs were conducted. In a second condition, students chose the order of programs and the reinforcers to be used. Speed of skill acquisition and the presence of competing behavior such as tantrums, aggression, escape attempts or idiosyncratic noncompliance responses were measured. Speed of skill acquisition did not differ between the two conditions, but competing behavior was markedly reduced during student choice conditions. Copyright 2002 John Wiley & Sons, Ltd. [source]