Terpstra Test Research Articles

Non-Parametric Test for Ordered Medians: The Jonckheere Terpstra Test

In clinical trials, sample size is usually lesser as compared to other epidemiological studies to make it more feasible and cost effective. Small sizes of such trials discourage the use of parametric test due to violation of the assumption under which they are applicable. Therefore, the use of nonparametric test is substantial in clinical trials to test two or more independent samples. The Kruskal-Wallis h test is an alternative to one-way ANOVA and can be used to identify significant differences among different populations. When we have several independent samples and assumed to be arranged orderly, Jonckheere Terpstra test is a best choice to compare population medians instead of means. For the application of Jonckheere Terpstra test the data from the study of cleaning methods for ultrasound probes are used. The Jonckheere Terpstra test is recommended over Kruskal-Wallis h test as it compares and provides significant difference between more than two population medians when they arranged in order. Therefore, the aim of this research paper was to explore the use and significance of Jonckheere-Terpstra test with the use of practical example.

Intra-Individual Response Variability Assessed by Ex-Gaussian Analysis may be a New Endophenotype for Attention-Deficit/Hyperactivity Disorder.

Intra-individual variability of response times (RTisv) is considered as potential endophenotype for attentional deficit/hyperactivity disorder (ADHD). Traditional methods for estimating RTisv lose information regarding response times (RTs) distribution along the task, with eventual effects on statistical power. Ex-Gaussian analysis captures the dynamic nature of RTisv, estimating normal and exponential components for RT distribution, with specific phenomenological correlates. Here, we applied ex-Gaussian analysis to explore whether intra-individual variability of RTs agrees with criteria proposed by Gottesman and Gould for endophenotypes. Specifically, we evaluated if normal and/or exponential components of RTs may (a) present the stair-like distribution expected for endophenotypes (ADHD > siblings > typically developing children (TD) without familiar history of ADHD) and (b) represent a phenotypic correlate for previously described genetic risk variants. This is a pilot study including 55 subjects (20 ADHD-discordant sibling-pairs and 15 TD children), all aged between 8 and 13 years. Participants resolved a visual Go/Nogo with 10% Nogo probability. Ex-Gaussian distributions were fitted to individual RT data and compared among the three samples. In order to test whether intra-individual variability may represent a correlate for previously described genetic risk variants, VNTRs at DRD4 and SLC6A3 were identified in all sibling-pairs following standard protocols. Groups were compared adjusting independent general linear models for the exponential and normal components from the ex-Gaussian analysis. Identified trends were confirmed by the non-parametric Jonckheere–Terpstra test. Stair-like distributions were observed for μ (p = 0.036) and σ (p = 0.009). An additional “DRD4-genotype” × “clinical status” interaction was present for τ (p = 0.014) reflecting a possible severity factor. Thus, normal and exponential RTisv components are suitable as ADHD endophenotypes.

Corporate Social Responsibility and Perception of Environmental Pillar in the Selected Set of the Slovak Enterprises

Abstract In spite of fact that problem of Corporate Social Responsibility (CSR) is very well known worldwide, it gets slowly into awareness in Slovakia. Nowadays more and more Slovak enterprises incorporate CSR principles into their practice and learn to profit from its implementation. This article based on the Carroll's three pillar CRS model, while the environmental pillar was selected as the most important one. On the sample of 58 Slovak enterprises we are verifying presence of a statistically significant effect of the legal form and number of employees (SME size category) on the implementation of environmental issues in the company. In the methodology we are using descriptive statistics, non-parametric methods (The Kruskal-Wallis Test, Jonckheere – Terpstra Test) and Crombach Alpha. The results of the analysis shows that the corporate legal form has no impact on the application of environmental policy, but there is an impact of the number or employees, respectively SME size category. Micro enterprises are not involved in the raising awareness on environmental policy and responsibility on the same extent as small companies. Similar differences between this two size groups we find in their extent of dealing with environmental research and development and protection of the natural environment.

Unbiasedness and biasedness of the Jonckheere–Terpstra and the Kruskal–Wallis tests

Finding the unbiasedness and biasedness of test statistics is important in testing a hypothesis. In this study, the unbiasedness/biasedness of the Jonckheere–Terpstra test is investigated for ordered alternatives. Our results show that the one-sided Jonckheere–Terpstra test is unbiased for the location parameter family of distributions and that the non-randomized two-sided Jonckheere–Terpstra test is biased for the shifted location parameter. Additionally, the unbiasedness/biasedness of the Kruskal–Wallis test is considered for the general two-sided alternatives. By giving a counter example, our investigation reveals that the Kruskal–Wallis test is biased against a shifted location parameter for unequal sample sizes. Our results indicate that we require to consider a bias correction for the nonparametric tests.

Exercise testing as a screening measure for ability to walk with aprosthesis after transfemoral amputation due to peripheral vascular disease

Purpose: To establish at which exercise-power level is the vascular response, as measured by oxygen uptake, closest to the response during the 6-min walk test (6 MWT) in people after lower-limb amputation due to peripheral vascular disease (PVD). Method: A prospective exploratory cohort study was conducted. 6 MWT and exercise testing using a hand-wheel ergometer (starting at 10 W and increasing the workload by 10 W) were performed in 101 consecutively recruited participants after transfemoral amputation due to PVD. Agreement of oxygen uptake during 6 MWT and exercise testing was compared between the groups defined by the exercise-power level reached. Results: Linear regression through origin with Chow test for comparing slopes indicated that oxygen uptake at 30 W agreed more with 6 MWT than at 20, 40 or 50 W. Analyses of observed differences (one-way ANOVA with post-hoc tests, Jonckheere–Terpstra test) confirmed 30 W to be the recommendable threshold. Conclusions: At the level of 30 W, the oxygen uptake during the exercise was the closest to the 6 MWT, so we estimated that to be the minimum required level for walking using a prosthesis after transfemoral amputation due to PVD.Implications for RehabilitationExercise testing after transfemoral amputation.Walking with a prosthesis causes notable strain to the person’s vascular system: after the 6-min walk test, the participants' heart rate reached 75% of the maximum predicted heart rate on average.The study shows that persons after transfemoral amputation due to peripheral vascular disease who reach the level of 30 W or more in exercise testing with an arm ergometer at admission to rehabilitation are likely to be able to walk in-doors using a prosthesis.

A comparison of rates and predictors of hospital readmission: Outpatient versus inpatient mastectomy for breast cancer.

116 Background: The odds of readmission have been reported to be slightly higher with outpatient (OP) compared to inpatient (IP) mastectomy, although overall rates are low. While OP mastectomy procedures have become more common, predictors of readmission and current rates are unknown. Methods: Observational study of women 18+ years who underwent mastectomy in California from 2005-2009 from the Healthcare Cost and Utilization Project (HCUP) linked state database. Associations of readmission and post-mastectomy complications with length of stay (LOS) were assessed using Jonkheere – Terpstra test for trend. Multivariate logistic regression was used to test the association of LOS with readmission to hospital within 30 days, adjusting for patient, clinical, and hospital factors. Results: Readmission rates for OP compared to IP mastectomy was 3.3 % vs. 5.6% (p<0.0001). OP mastectomy had the highest hematoma/seroma and chemotherapy related anemia/ neutropenia readmissions (19% p=0.0112; 2.9% p=0.0009). Readmits for cardiopulmonary events were higher for the longest LOS. Multivariate analysis showed increased readmission rates by LOS, race, payer, comorbidities (all p-values <0.0001). Odds of readmission were higher with increasing LOS vs. OP (1d OR 1.13 95% CI 0.99-1.3; 2d OR 1.6 95%CI 1.4-1.8; ≥3d OR 3.0 95%CI 2.6-3.4). Increased odds of readmission was associated with African-Americans (OR 1.5 95%CI 1.2-1.9) and Whites (OR 1.4 95%CI 1.2-1.7) vs. Asians. Revisit rates were higher with Medicare (OR 1.7 95%CI 1.4-1.9) and Medicaid (OR 1.6 95%CI 1.3-1.8) compared to private insurance. The highest readmission rates were ≥ 3 comorbidities (OR 2.7 95%CI 2.2-3.2). Conclusions: In California, readmission rates increase with increasing LOS. Risks of readmission following IP mastectomy are higher compared to OP. Low readmission rates suggest appropriate selection of patients for OP mastectomy. However, subsets of patients are at higher risk of readmission. Additional studies of patients with extended LOS; racial disparities in access to services; and evaluation of payer policies are needed to improve care and decrease hospital readmissions.

Expansion of acidophytic late-successional bryophytes in Dutch fens between 1940 and 2000

Question How did frequency and local abundance of key bryophytes in Dutch fens change between 1940 and 2000? Location The Netherlands. Methods A total of 1939 vegetation releves, objectively assigned to the class Parvocaricetea and dating from the period 1940–1999 inclusive, were extracted from a national Netherlands database. From this releve set, two additional data sets were derived; these were syntaxonomically homogeneous at the association level. One contained 418 Scorpidio-Caricetum diandrae releves and the other 956 Pallavicinio-Sphagnetum releves. The following analyses were done for these three data sets: frequency and local abundance change of 13 bryophyte species over three 20-yr periods were described using logistic regression and the nonparametric Jonckheere–Terpstra test, respectively. Results Acidophytic, late-successional species, notably Sphagnum palustre and Polytrichum uliginosum, have replaced relatively early-successional species such as brown mosses, Sphagnum subnitens and Sphagnum squarrosum during the studied period. The results were mostly consistent across the three data sets. Local abundance patterns generally paralleled those of frequency, although cover trends were often less robust. Conclusions Drastic changes have taken place in the bryophyte layer of Dutch fens between 1940 and 2000. Our study has shown that acidophytic, late-successional bryophytes have replaced relatively early-successional brown moss and Sphagnum species. Both hydrological changes and nutrient shifts (in particular phosphorus enrichment and ammonium toxicity) appear to have been responsible for the observed rapid shifts in the bryophyte layer of Dutch fens.

Generic Health-related Quality of Life is Significantly Worse in Varicose Vein Patients with Lower Limb Symptoms Independent of Ceap Clinical Grade

ObjectivesTo determine the relationship between lower limb symptoms and generic health-related quality of life (HRQL) in patients with varicose veins (VV). Methods284 patients on the waiting list for VV treatment completed the Short Form-12 (SF12) and a questionnaire asking about the presence of lower limb symptoms commonly attributed to venous disease (pain or ache, itching, tingling, cramp, restless legs, a feeling of swelling, and heaviness). ResultsMedian age was 57 years (interquartile range 45–67); 100 (35%) were male, and 182 (64%) had CEAP clinical grade 2 or 3 disease. Jonckheere–Terpstra test for trend revealed that both physical (P < .0005) and mental (P = .001) HRQL worsened as the reported number of symptoms increased.Patients reporting tingling (P = .016, Mann–Whitney U test), cramp (P = .001), restless legs (P < .0005), swelling (P < .0005), and heaviness (P < .0005) had a significantly worse physical HRQL than those who did not. Mental HRQL was also significantly worse in patients with tingling (P = .010), cramp (P = .008), restless legs (P = .040), swelling (P = .001), and heaviness (P = .035).These significant relationships remained, and pain was also correlated with worse physical HRQL (P = .011), when linear regression was performed to control for CEAP clinical grade, age and sex. ConclusionsPhysical and mental HRQL is significantly worse in VV patients with lower limb symptoms irrespective of the clinical stage of disease. This observation confirms that VV are not primarily a cosmetic problem and that NHS rationing of treatment to those with CEAP C4-6 disease excludes many patients who would benefit from intervention in terms of HRQL. Generic HRQL instruments also allow comparison with interventions for other chronic conditions.

Blood persistent organochlorine pesticides in pregnant women in relation to physical and environmental variables in The Hokkaido Study on Environment and Children's Health

The aim of this study was to document the exposure levels of pregnant women in Hokkaido to persistent organochlorine (POC) pesticides and the relationship between the body burdens of these pesticides and the study population's characteristics, such as age, pre-pregnancy body weight and calendar year in which blood was collected. From 2002 to 2005, whole blood samples were obtained from 186 pregnant women (aged 17 to 47years) from the population of 514 women registered with the Sapporo Toho hospital cohort of the Hokkaido Study. Blood samples were analyzed by GC/NCIMS and GC/HRMS to quantify 29 POC pesticides. The subjects' demographic details were obtained from medical records and self-administered questionnaires. The Jonckheere–Terpstra test was used to determine relevant trends in the chemical concentrations of these pesticides and their relationship to the subjects' demographic details. Twenty-one of the 29 targeted compounds (including pesticides that have never been used in Japan, such as Mirex, Parlar-26 and Parlar-50) were detected in whole blood samples, and their log-transformed concentrations were found to significantly correlate with each other. The concentrations of p,p′-DDD, o,p′-DDE, p,p′-DDE, Parlar-26 and Parlar-50 declined from 2002 to 2005 (p<0.05). The pesticide concentrations appeared to have stronger associations with past conception than with parity, with most pesticide concentrations declining in a manner that appeared inversely related to past conceptions (p<0.05). Maternal age was positively associated with the following pesticide concentrations: p,p′-DDE, chlordanes group, cis-heptachlorepoxide, β-HCH and mirex. Maternal pre-pregnancy body weight was positively associated with the concentrations of dieldrin, HCB, β-HCH, Parlar-26 and Parlar-50, and appeared to be more strongly related to the body burdens of POC pesticides when compared with BMI associations. Further studies are required to evaluate the effects of POC pesticides on human health with regard to reproductive outcomes and child development.

A Study on Reliability and Validity of the Nurses' Global Assessment of Suicide Risk (NGASR) for Psychiatric Inpatients

Purpose: Assessment of suicide risk is a critical task for nurses, especially for nurses working with psychiatric inpatients. The purpose of this study was to verify the reliability and validity of the Nurses' Global Assessment of Suicide Risk (NGASR) for psychiatric inpatients. Methods: This study was methodological study. A scale composed of 15 items was used with 106 psychiatric inpatients in open and closed psychiatric units of a tertiary hospital. Cohen's kappa coefficient, Intraclass correlation, factor analysis and Jonckheere-Terpstra Test for Ordered Alternatives were used for statistic analysis. Results: Main results were as follows; Reliability of the scale was supported with a total intraclass correlation coefficient of .890 (range from .722 to 1.000). In investigating construct validity, 15 items loaded on six factors which explained 63.4% of total variance. Also the Jonckheere- Terpstra test revealed a significant trend in the order of median scores of NGASR across the three groups of Evaluation of Suicide Risk (ESR). These results supported the criterion-related validity of the scale. Conclusion: The findings in this study indicate that this scale is reliable and valid in assessing suicide risk of psychiatric inpatients. Therefore it is an appropriate scale to assess suicide risk for psychiatric inpatients.

A Nonparametric Test for the Ordered Alternative Based on Fast Discrete Fourier Transform Coefficient

We propose a distribution-free test, which has two main purposes. First, the test can assist in alleviating some of the problems that existing tests have with higher powers when the assumed a priori ordering among the parameters is incorrect. Second, the new test can detect the monotone trends (non-decreasing ordered and non-increasing ordered) with only one derived process. Here we propose a new test, which combines and orders all observations from least to greatest; the approximate distribution of Fourier coefficients is utilized and tests whether the location parameters are serially non-decreasing or non-increasing with the groups. Utilizing the Monte Carlo simulation, we show that the proposed test is a significant improvement over the Terpstra and Magel test [Terpstra, J. T. and Magel, R. C., “A New Nonparametric Test for the Ordered Alternative Problem,” Nonparametric Stat., Vol. 15, 2003, pp. 289–301], that is, decreasing more powers for the situation when an investigator falsely assumes an a priori ordering relationship.

Jonckheere-Terpstra 추세 검정통계량에 근거한 비모수적 층화분석법

Clinical trials are often carried out as multi-center studies because the patients enrolled for a trial study are very limited in one particular hospital. In these circumstances, the use of an ordinary Jonckheere (1954) and Terpstra (1952) test for testing trend among several independent treatment groups is invalid. We propose a the stratified Jonckheere-Terpstra test based on van Elteren (1960)'s stratified test of Wilcoxon (1945) statistics and an application of our method is demonstrated through example data. A simulation study compares the efficiency of stratified and unstratified Jonckheere-Terpstra trend tests.

Severity of infection following the introduction of new infection control measures for medical abortion

Background In response to concerns about serious infections following medical abortion, in early 2006 the Planned Parenthood Federation of America changed the route of misoprostol administration from vaginal to buccal and required either routine antibiotic coverage or universal screening and treatment for chlamydia; in July 2007, the Planned Parenthood Federation of America began requiring routine antibiotic coverage for all medical abortions. We previously reported a pronounced drop in the rate of serious infections following the adoption of these new infection control measures. Our objective in this study was to assess whether the degree of severity of the serious infections differed in the three infection control groups (vaginal misoprostol and no antibiotics; buccal misoprostol and screen-and-treat method; buccal misoprostol and routine antibiotics) or, equivalently, to assess whether the declines in rates of serious infections after the adoption of new infection control measures differed across the degree of severity categories. Of particular importance is whether the new infection control measures selectively reduced the least severe serious infections but did not diminish the rate of the most severe infections. Methods We performed a retrospective analysis assessing the degree of severity of infections before infection controls were implemented and after each of the two new measures was adopted: buccal administration of antibiotics with either screen-and-treat method or routine antibiotic coverage. We ranked the severity of infection from 1 (when treatment occurred in an emergency department) to 4 (when death occurred). We compared the distributions of the severity of serious infections in the three infection control groups (none; buccal misoprostol and screen-and-treat method; buccal misoprostol and routine antibiotics) or, equivalently, assessed whether the declines in rates of serious infections after the adoption of new infection control measures differed across the degree of severity categories using the Jonckheere–Terpstra test for a doubly ordered 4×3 table. Results The distribution of infection by severity was the same for all three infection control groups. Likewise, when the two new infection control groups — buccal misoprostol plus either screen-and-treat method or routine antibiotics — were combined, the distribution of infection by severity was the same before and after the new measures were implemented. Conclusion The pronounced decline in the rate of serious infections occurred in each category of severity.

Loss of surface enamel after bracket debonding: An in-vivo and ex-vivo evaluation

The objective of this study was to evaluate the surface enamel after bracket debonding and residual resin removal. Thirty patients (female, 20; male, 10; mean age, 18.4 years) who completed orthodontic treatment with fixed appliances (Twin Brackets, 3M Unitek, Monrovia, Calif) (n = 525) were included. The amounts of adhesive left on the tooth surfaces and the bracket bases were evaluated with the adhesive remnant index (ARI). ARI(tooth) (n = 498) was assessed on digital photographs by 2 operators. After resin removal and polishing, epoxy replicas were made from the maxillary anterior teeth (n = 62), and enamel surfaces were scored again with the enamel surface index. Elemental analysis was performed on the debonded bracket bases by using energy dispersive x-ray spectrometry mean area scanning analysis. The percentages of calcium and silicon were summed up to 100%. Tooth damage was estimated based on the incidence of calcium from enamel in relation to silicon from adhesive (Ca%) and the correlation between the ARI(bracket) and Ca%. While ARI(tooth) results showed score 3 as the most frequent (41%) (P<0.05), followed by scores 0, 1, and 2 (28.7%, 17.9%, and 12.4%, respectively), ARI(bracket) results showed score 0 more often (40.6%) than the other scores (P<0.05). Maxillary anterior teeth had significantly more scores of 3 (49%) than the other groups of teeth (10%-25%) (chi-square; P<0.001). There were no enamel surface index scores of 0, 3, or 4. No correlation between the enamel surface index and ARI(tooth) scores was found (Spearman rho = 0.014, P = 0.91). The incidence of Ca% from the scanned brackets showed significant differences between the maxillary and mandibular teeth (14% ± 8.7% and 11.2% ± 6.5%, respectively; P <0.05), especially for the canines and second premolars (Kruskal-Wallis test, P<0.01). With more remnants on the bracket base, the Ca% was higher (Jonckheere Terpstra test, P<0.05). Iatrogenic damage to the enamel surface after bracket debonding was inevitable. Whether elemental loss from enamel has clinical significance is yet to be determined in a long-term clinical follow-up of the studied patient population.

RE: DNA damage detected by the alkaline comet assay in the liver of mice after oral administration of tetrachloroethylene. (Mutagenesis, 25, 133-138, 2010)

In their Letter to the Editor, Lillford et al. have questioned the analyses and conclusions of the results presented in our recently published paper (1). In this study, mice were exposed to tetrachloroethylene at the doses of 0 (vehicle control), 1000 and 2000 mg/kg/day. From the results obtained, we concluded that tetrachloroethylene is weakly genotoxic in the liver of mice. This conclusion was not shared by Lillford et al. as it, in their view, was heavily dependent on statistical analysis and did not take biological relevance of the results into account. We do not agree with this opinion and, therefore, the criteria and arguments we have taken into account in the evaluation of the results are further elaborated below. In toxicity testing, it is generally held that the finding of a dose-related effect of a test substance provides a very strong argument for concluding that the observed effect is biologically relevant. In the study we have published, it was noticed that the group mean values for tail intensity in the liver increased with the dose, suggesting a biologically relevant effect of tetrachloroethylene, i.e. induction of DNA damage. This positive trend was then analysed with the Jonckheere–Terpstra test and found to be statistically significant. Thereby, the statistical analysis has been used as an aid in evaluating the results, and the outcome of the analysis showed that there was a low probability for the observed positive trend to occur by chance only. We disagree with the comment by Lillford et al. stating that our conclusion was heavily dependent on statistical analysis and that statistical analysis was the sole criterion for a positive effect. The biological relevance of the effect, demonstrated by the dose-related increase in tail intensity in the liver, was considered first and has been taken into account for determining the positive response. Lillford et al. argue that groups of mice treated with tetrachloroethylene exhibited tail moments and tail intensities that were similar to those of the concurrent vehicle control group. Given the flexible meaning of the word similar and that the DNA-damaging effect of tetrachloroethylene was weak, we understand the basis for such a statement. However, 8 of the 12 tetrachloroethylene-treated animals had higher tail intensity values in the liver than the animal with the highest tail intensity value in the concurrent vehicle control group and, furthermore, the dose-related increase in tail intensity established in the liver implies that the mean tail intensity values for the three experimental groups were indeed different. We note that Lillford et al. comment that the maximum group mean increase was only 1.43-fold (tail intensity in the liver, 2000 mg/kg group) above the vehicle control group and that the increase in tail moment in this group was only 1.36-fold. In our opinion, the crucial result of the study was that a weak DNA-damaging effect of tetrachloroethylene was established. Whether the magnitude of this weak effect was 1.43-fold or 1.36-fold is of less importance. Furthermore, the reference to tail moment is of limited value since according to international expert panel recommendations for conducting the alkaline in vivo comet assay (2), the use of tail intensity (i.e. per cent DNA in tail) is recommended, as indicated by the following statement:

Potential Confounding of the Association Between Exposure to Nucleoside Analogues and Mitochondrial Dysfunction in HIV-Uninfected and Indeterminate Infants

Potential Confounding of the Association Between Exposure to Nucleoside Analogues and Mitochondrial Dysfunction in HIV-Uninfected and Indeterminate Infants

Utility of the Psychosocial Assessment of Candidates for Transplantation (PACT) Scale in Allogeneic BMT

The psychosocial assessment of candidates for transplantation (PACT) scale was completed before the transplant on 120 patients who underwent allogeneic transplant from November 2003 to June 2007. The PACT has eight subscales, each rated on a 5-point scale, and an initial and final rating independently based on the rater’s overall impressions of the candidate’s acceptability for transplant. This exploratory study assessed the clinical utility of the PACT scale for psychosocial screening in allogeneic BMT. Associations of the PACT subscales and the final rating with sixteen post transplant medical outcomes were examined using the Jonchkheere–Terpstra test, the Cochran–Armitage test or the Cox proportional hazards analysis. Significant relationships (Pp0.05) between PACT subscales and medical outcomes are as follows: better compliance with medications and medical advice associates with lower in-hospital mortality, shorter length of stay and readmission duration, and faster neutrophil and platelet engraftment; better scores on drug/alcohol use associates with faster platelet engraftment; better scores on family/support system availability and on relevant knowledge and receptiveness to education associates with decreased risk of mortality. The final rating score and medical outcomes are not significantly related; however, study findings underscore the prognostic value of the PACT subscales and the potential utility for screening of BMT candidates.

A Nonparametric Test for the Ordered Alternative Based on Kendall's Correlation Coefficient

Several methods have been developed for testing the ordered alternative. These include the Jonckheere–Terpstra (JT) test (Jonckheere, 1954; Terpstra, 1952), a modified JT test (MJT) (Tryon and Hettmansperger, 1987), and a test proposed by Terpstra and Magel (TM) (Terpstra and Magel, 2003), among others. This article proposes a new method for testing the ordered alternative. The proposed test is based on Kendall's tau statistic. The asymptotic distribution of the test statistic is given. A Monte Carlo simulation study is conducted comparing the estimated powers of the proposed test with existing tests under a variety of sample sizes and distributions.

Selective attention deficits reflect increased genetic vulnerability to schizophrenia

BackgroundImpairment in attention is prominent in schizophrenia and may be a valuable genetic indicator for vulnerability to this disease. AimsWe set out to characterize the attention deficits that may be associated with genetic liability to schizophrenia. MethodsWe compared attention performance in 55 people with schizophrenia, 95 of their first-degree relatives, and 61 unrelated controls. We also segregated presumed obligate carriers of genetic risk (POCs, N=12) and compared their performance with that of controls. ResultsAlthough the relatives of people with schizophrenia did not significantly differ from the normal controls on the tasks of attention, their scores were significantly ordered such that patients>relatives>normal controls during tasks of sustained and selective attention as measured by the Jonckheere–Terpstra Test (p<.05). Additionally, POCs were significantly worse than normal controls during selective attention tasks such as the Stroop (p=.03) and Letter Cancellation Task (p=.04). ConclusionsHeterogeneity in the first-degree relatives may have diluted the attention deficits present in those who are at genetic risk for schizophrenia. On the other hand, our findings in the more homogeneous group of POCs suggest that selective attention may be an indicator of genetic liability for schizophrenia.

The effects of prolonged rose odor inhalation in two animal models of anxiety

Aim To investigate the anxiolytic effects of prolonged rose odor exposure, mature gerbils were exposed to acute (24 h), chronic (2 week) rose odor, or a no odor condition. Anxiolytic effects were assessed using the elevated plus maze and black white box. Rose odor profiles were compared with diazepam (1 mg/kg) i.p. The Jonckheere–Terpstra test was used, with the Mann–Whitney U test to examine significant group differences. In the elevated plus maze, spatiotemporal measures, altered by diazepam, were unaffected by rose oil, whereas exploration, increased (headdip frequency: acute U = 100, p < 0.001; chronic U = 13, p < 0.001). In the black white box, rose oil had anxiolytic spatiotemporal and exploratory behavior effects: latency to move from the white to the black compartment (acute U = 182, p < 0.01, chronic U = 179, p < 0.05), percentage time in the white compartment (acute U = 168, p < 0.01, chronic U = 149, p < 0.01) and exploration, rear-sniff frequency white (acute U = 100, p < 0.001; chronic U = 99, p < 0.001) increased. The percentage of time in the dark area decreased (acute U = 160, p < 0.01, chronic U = 178, p < 0.05). This anxiolytic profile strengthened after chronic exposure to rose odor, transitions between the compartments ( U = 167, p < 0.01) and percentage of time moving around the arena ( U = 154, p < 0.001) increased. Conclusion This profile was more representative of modern anxiolytics, for example some serotonergic agents, rather than benzodiazepine type drugs.