Use of ratings of perceived exertion to anticipate treadmill test termination in patients taking beta-blockers

This investigation identified a perceptually-based "warning zone" that can be used to anticipate termination of treadmill tests administered to individuals taking beta-blockers. The use of ratings of perceived exertion to anticipate test termination may be valuable given the attenuation of heart rate associated with the use of this class of medication. Sixteen men with coronary artery disease participated in this investigation. Ratings of perceived exertion (Borg 6-20 Scale) were estimated during the last 15 sec. of each minute of a progressively incremented treadmill test. Tests were terminated when participants indicated they were too fatigued to continue. The time-to-test termination was determined from the point that participants estimated a rating of 10, 11, 12, 13, 14, 15, 16, and 17 in order to determine the rating that was less than or equal to the time associated with a single exercise stage. A rating of 14 was associated with impending termination, which can be used as a "warning zone." The time to termination corresponding to a rating of 14 was 153.1 sec. (SD = 27.0). Participants exercised for 153.1 sec. (SE = 27.0) after estimating a rating of 14. Once a rating of 14 is reached, volitional test termination will occur before the next exercise stage is completed.     

Collective self-esteem: role of social context among Asian-American college students

The present study explored several layers of individual and contextual variables as related to collective self-esteem among 304 Asian-American college students. The findings suggested that variables, such as immigration generation status and cultural identification, were significantly associated with Private collective self-esteem (personal evaluation of one's ethnic group), while contextual variables, including number of same-ethnicity peers and community ethnic composition, were associated with Public collective self-esteem (judgment of how other people evaluate one's ethnic group). In addition to these variables, age and fluency of heritage language were positively related to Membership esteem (how worthy one feels as a member of one's ethnic group). For the Importance of identity (the importance of ethnic group membership to one's self-concept), cultural identification, number of same-ethnicity peers, and perceived campus climate were statistically significant. The implication of the present findings for future research is discussed.     

Association of the DAT1 genotype with inattentive behavior is mediated by reading ability in a general population sample

Attention deficit hyperactivity disorder (ADHD) and reading disability (RD) frequently co-occur in the child population and therefore raise the possibility of shared genetic etiology. We used a quantitative trait loci (QTL) approach to assess the involvement of the dopamine transporter (DAT1) gene polymorphism in mediating reading disability and poor attention in a general population sample of primary school children aged 6-11 years in the UK. The potential confounding effects of IQ and chronological age were also investigated. We found an independent association between the homozygous DAT1 10/10 repeat genotype and RD that was not accounted for by the level of ADHD symptoms. This finding suggests that the DAT1 gene polymorphism may influence a common neural mechanism underlying both reading acquisition and ADHD symptoms.     

Cathodal transcranial direct current stimulation of the right Wernicke's area improves comprehension in subacute stroke patients

Previous studies have shown the appearance of right-sided language-related brain activity in right-handed patients after a stroke. Non-invasive brain stimulation such as transcranial direct current stimulation (tDCS) and repetitive transcranial magnetic stimulation (rTMS) have been shown to modulate excitability in the brain. Moreover, rTMS and tDCS have been found to improve naming in non-fluent post-stroke aphasic patients. Here, we investigated the effect of tDCS on the comprehension of aphasic patients with subacute stroke. We hypothesized that tDCS applied to the left superior temporal gyrus (Wernicke’s area) or the right Wernicke’s area might be associated with recovery of comprehension ability in aphasic patients with subacute stroke. Participants included right-handed subacute stroke patients with global aphasia due to ischemic infarct of the left M1 or M2 middle cerebral artery. Patients were randomly divided into three groups: patients who received anodal tDCS applied to the left superior temporal gyrus, patients who received cathodal tDCS applied to the right superior temporal gyrus, and patients who received sham tDCS. All patients received conventional speech and language therapy during each period of tDCS application. The Korean-Western Aphasia Battery (K-WAB) was used to assess all patients before and after tDCS sessions. After intervention, all patients had significant improvements in aphasia quotients, spontaneous speech, and auditory verbal comprehension. However, auditory verbal comprehension improved significantly more in patients treated with a cathode, as compared to patients in the other groups. These results are consistent with the role of Wernicke’s area in language comprehension and the therapeutic effect that cathodal tDCS has on aphasia patients with subacute stroke, suggesting that tDCS may be an adjuvant treatment approach for aphasia rehabilitation therapy in patients in an early stage of stroke.     

EMG and kinematics analysis of the trunk and lower extremity during the sit-to-stand task while wearing shoes with different heel heights in healthy young women

This study investigated the EMG characteristics and the kinematics of the trunk and lower extremity during the sit-to-stand (STS) task while wearing 1-, 4-, and 8-cm high-heeled shoes. We examined differences in the EMG data of the internal oblique, erector spinae, medial hamstring, and rectus femoris muscles during the STS task. The motion of the hip joint during an STS task was measured with a NorAngle Electrogoniometer System. Twelve young healthy women were recruited to this study. EMG characteristics and the hip joint angle were recorded during the performance of an STS task by subjects wearing high-heeled shoes of three different heel heights. The muscle onset time and EMG activity during this task were analyzed. In 8-cm high-heeled shoes, the onset time for the erector spinae muscle was significantly delayed, and the onset latency for the medial hamstring and the rectus femoris was significantly decreased. There was increased activity in the erector spinae and rectus femoris muscle during this task when wearing 8-cm high-heeled shoes. The initial hip flexion angle at the start point of the STS task did not differ among the 1-, 4-, and 8-cm heel-height conditions, but the trunk flexion angle, corresponding to the displacement between the peak hip flexion and initial hip flexion, was significantly larger in the 8-cm heel-height condition than in the 1- and 4-cm heel-height conditions. The findings suggest that excessive heel height has the potential to induce muscle imbalance during the STS task.     

Further insights into the relationship between the experience of life adversity and interrogative suggestibility

Research over the past few years has uncovered a consistent link between the reporting of intense negative life events and interrogative suggestibility on the Gudjonsson Suggestibility Scale (GSS). This study (N = 130) now investigates the functional form of this relationship. Findings show that a linear regression model provides the most acceptable fit to the observed values for yield 1, yield 2, shift and total suggestibility scores. However, results also show the presence of non linear, quadratic, aspects to the relationship between the experience of life adversity and yield 1 scores. Up until now GSS scores were thought to increase linearly with level of adversity experienced: this study provides some evidence that, for the yield 1 subscale of the GSS, this may not be the case – high levels of adversity may not necessarily lead to an increased risk of accepting misleading information during questioning as once presumed.     

Omitted Variables in Multilevel Models

Statistical methodology for handling omitted variables is presented in a multilevel modeling framework. In many nonexperimental studies, the analyst may not have access to all requisite variables, and this omission may lead to biased estimates of model parameters. By exploiting the hierarchical nature of multilevel data, a battery of statistical tools are developed to test various forms of model misspecification as well as to obtain estimators that are robust to the presence of omitted variables. The methodology allows for tests of omitted effects at single and multiple levels. The paper also introduces intermediate-level tests; these are tests for omitted effects at a single level, regardless of the presence of omitted effects at a higher level. A simulation study shows, not surprisingly, that the omission of variables yields bias in both regression coefficients and variance components; it also suggests that omitted effects at lower levels may cause more severe bias than at higher levels. Important factors resulting in bias were found to be the level of an omitted variable, its effect size, and sample size. A real data study illustrates that an omitted variable at one level may yield biased estimators at any level and, in this study, one cannot obtain reliable estimates for school-level variables when omitted child effects exist. However, robust estimators may provide unbiased estimates for effects of interest even when the efficient estimators fail, and the one-degree-of-freedom test helps one to understand where the problem is located. It is argued that multilevel data typically contain rich information to deal with omitted variables, offering yet another appealing reason for the use of multilevel models in the social sciences. This research was supported by the National Academy of Education/Spencer Foundation and the National Science Foundation, Grant Number SES-0436274.     

The effect of salience on mental accounting: how integration versus segregation of payment influences purchase decisions

Although mental accounting principles are generally robust, the integration‐of‐losses principle often fails. This research argues that when information salience is high, people actively segregate. To demonstrate that effect, this research uses purchase decision making for which the total payment is a key decision factor and compares examples such as the following equivalent total payments: “$120.95 for a stroller plus $19.95 for shipping” (i.e., segregation) versus “$140.90 for a stroller including shipping” (i.e., integration). Two studies demonstrate that integration increases purchase intentions when the salience of the smaller payment is higher. Specifically, integration leads to higher purchase intentions than does segregation when (1) the surcharge is visually more salient, (2) the surcharge is easy to process, and (3) price perceptions are stimulus instead of recall driven. Therefore, this research extends mental accounting by identifying conditions in which the integration‐of‐losses principle is likely to prevail. Copyright © 2006 John Wiley & Sons, Ltd.