Negative affectivity and social inhibition in cardiovascular disease: evaluating type-D personality and its assessment using item response theory

OBJECTIVE: Individuals with increased levels of both negative affectivity (NA) and social inhibition (SI)-referred to as type-D personality-are at increased risk of adverse cardiac events. We used item response theory (IRT) to evaluate NA, SI, and type-D personality as measured by the DS14. The objectives of this study were (a) to evaluate the relative contribution of individual items to the measurement precision at the cutoff to distinguish type-D from non-type-D personality and (b) to investigate the comparability of NA, SI, and type-D constructs across the general population and clinical populations. METHODS: Data from representative samples including 1316 respondents from the general population, 427 respondents diagnosed with coronary heart disease, and 732 persons suffering from hypertension were analyzed using the graded response IRT model. RESULTS: In Study 1, the information functions obtained in the IRT analysis showed that (a) all items had highest measurement precision around the cutoff and (b) items are most informative at the higher end of the scale. In Study 2, the IRT analysis showed that measurements were fairly comparable across the general population and clinical populations. CONCLUSIONS: The DS14 adequately measures NA and SI, with highest reliability in the trait range around the cutoff. The DS14 is a valid instrument to assess and compare type-D personality across clinical groups.     

Gaze pursuit, 'attention pursuit' and their effects on cortical activations

A moving object draws our attention to it and we can track the object with smooth pursuit eye movements (SPEM). Gaze and attention are usually directed to the same object during SPEM. In this study we investigated whether gaze and attention can be divided during pursuit. We explored the cortical control of ocular tracking and attentive tracking and the role of focused and divided attention. We presented a sinusoidally moving target for pursuit and simultaneously a stationary target for fixation. Gaze could be directed to the pursuit target and attention to the fixation target or vice versa, or gaze and attention were directed to the same (moving or stationary) target. We found that gaze (overt) and attentive (covert) pursuit similarly activated the cortical oculomotor network. Gaze pursuit showed higher activations than attentive pursuit. Activations, specific to the dissociation of attention from gaze and independent of eye movements, were found solely in the posterior parietal cortex. A cue indicating a forthcoming attention task activated large parts of the cortical SPEM network, as a kind of preparatory mechanism. We did not find any attention-related regions outside the well-known visuo-oculomotor network. We conclude that attention control during gaze pursuit and gaze fixation occur within the cortical SPEM network, supporting the premotor theory of attention [Rizzolatti, G., Riggio, L., Dascola, I. & Umilta, C. (1987) Neuropsychologia, 25, 31-40].     

过程管理理论在压疮护理三级监控中的应用

目的：探讨过程管理在压疮护理三级监控中的有效性。方法：将我院2005、2006年住院患者压疮发生情况分为两组,运用过程管理理论。实施了质控组长、科护士长、护理部三级监控。结果：实施压疮三级监控后,降低了压疮的发生率。结论：过程管理理论在压疮护理三级监控中应用,有效地使我院护理人员增强了预防压疮重于治疗的意识,加强了责任心,把降低压疮的发生作为护理工作目标之一。     

Synergic mechanism and fabrication target for bipedal nanomotors

Inspired by the discovery of dimeric motor proteins capable of undergoing transportation in living cells, significant efforts have been expended recently to the fabrication of track-walking nanomotors possessing two foot-like components that each can bind or detach from an array of anchorage groups on the track in response to local events of reagent consumption. The central problem in fabricating bipedal nanomotors is how the motor as a whole can gain the synergic capacity of directional track-walking, given the fact that each pedal component alone often is incapable of any directional drift. Implemented bipedal motors to date solve this thermodynamically intricate problem by an intuitive strategy that requires a hetero-pedal motor, multiple anchorage species for the track, and multiple reagent species for motor operation. Here we performed realistic molecular mechanics calculations on molecule-scale models to identify a detailed molecular mechanism by which motor-level directionality arises from a homo-pedal motor along a minimally heterogeneous track. Optimally, the operation may be reduced to a random supply of a single species of reagents to allow the motor's autonomous functioning. The mechanism suggests a distinct class of fabrication targets of drastically reduced system requirements. Intriguingly, a defective form of the mechanism falls into the realm of the well known Brownian motor mechanism, yet distinct features emerge from the normal working of the mechanism.     

Fluctuations in density of an outbreak species drive diversity cascades in food webs

Patterns in food-web structure have frequently been examined in static food webs, but few studies have attempted to delineate patterns that materialize in food webs under nonequilibrium conditions. Here, using one of nature's classical nonequilibrium systems as the food-web database, we test the major assumptions of recent advances in food-web theory. We show that a complex web of interactions between insect herbivores and their natural enemies displays significant architectural flexibility over a large fluctuation in the natural abundance of the major herbivore, the spruce budworm (Choristoneura fumiferana). Importantly, this flexibility operates precisely in the manner predicted by recent foraging-based food-web theories: higher-order mobile generalists respond rapidly in time and space by converging on areas of increasing prey abundance. This "birdfeeder effect" operates such that increasing budworm densities correspond to a cascade of increasing diversity and food-web complexity. Thus, by integrating foraging theory with food-web ecology and analyzing a long-term, natural data set coupled with manipulative field experiments, we are able to show that food-web structure varies in a predictable manner. Furthermore, both recent food-web theory and longstanding foraging theory suggest that this very same food-web flexibility ought to be a potent stabilizing mechanism. Interestingly, we find that this food-web flexibility tends to be greater in heterogeneous than in homogeneous forest plots. Because our results provide a plausible mechanism for boreal forest effects on populations of forest insect pests, they have implications for forest and pest management practices.     

Changes of brain activity in the neural substrates for theory of mind during childhood and adolescence

Theory of mind (ToM) refers to the ability to attribute independent mental states, such as beliefs, preferences and desires, to the self and others. Neuroimaging studies of normal adults have consistently demonstrated the importance of particular brain regions for ToM, the superior temporal sulcus (STS), temporal pole (TP) and the medial prefrontal cortex (MPFC). However, there are little data showing how ToM develops during childhood and adolescence. Such data are important for understanding the development of social functioning and its disorders. The authors used functional magnetic resonance imaging to study age-related changes in brain activity associated with ToM during childhood and early adolescence (9-16 years). Normally developed children and adolescents demonstrated significant activation in the bilateral STS, the TP adjacent to the amygdala (TP/Amy) and the MPFC. Furthermore, the authors found a positive correlation between age and the degree of activation in the dorsal part of the MPFC; in contrast, a negative correlation was found for the ventral part of the MPFC. The authors also found a positive correlation between the Z coordinate of the peak activation in the MPFC and age. The data indicated that activity in the MPFC associated with ToM shifted from the ventral to the dorsal part of the MPFC during late childhood and adolescence. No age-related changes were found in the STS and the TP/Amy regions. The authors consider that the age-related brain activity observed in the present study may be associated with the maturation of the prefrontal cortex and the associated development of cognitive functions.     

Learning and Retaining Normal Radiographic Chest Anatomy: Does Preclinical Exposure Improve Student Performance?

RATIONALE AND OBJECTIVES: Although most would concur that preclinical exposure to radiology is a desirable goal, specific learning objectives have been more difficult to delineate. It is also important to assess what is learned and to determine how well it is retained or "retrievable." This study was developed in an attempt to document the extent to which specific measures of preclinically acquired knowledge may be retained and retrieved for later clinical application. MATERIAL AND METHODS: The Anatomic Structure Identification Quiz (ASIQ, or Quiz), previously described in Feigin et al (Academic Radiology 2005) was administered to 236 medical students at the conclusion of the required second-year course, as a 10-item written Quiz based on a projected frontal and lateral chest image. The 10-item Quiz was also administered to 555 senior medical students (194 of which had been included in previous work) on the first day of the Uniformed Services University of the Health Sciences basic radiology elective. Finally, the identical Quiz was completed by 74 of these 555 senior medical students at the conclusion of the academic portion of the elective, approximately 3 weeks after the administration of the first quiz. RESULTS: The second-year students scored a mean of 7.15 points of a possible 10 points with a standard deviation (SD) of 1.42. The senior students completing the quiz at the beginning of the elective scored an average of 4.42 (SD 1.34) compared to a score of 8.65 (SD 1.24) 3 weeks later. CONCLUSION: Long-term recall of specific radiologic structures learned in the second year of medical school was poor despite evidence documenting good initial (short-term) retention of tested information. However, after a brief review, consisting of the Quiz itself, followed by 3 weeks of general radiology emphasizing abnormal chest imaging, the senior students demonstrated a near doubling of their ability to correctly identify these structures, as well as an improvement compared with scores obtained during the second year. Thus the value of a preclinical course in radiology may be not only to teach principles of radiology and to stimulate interest in the discipline, but also, by repetition and reinforcement, to facilitate and possibly improve later recall and retention of important radiographic material.     

The influence of emotion-focused rumination and distraction on depressive symptoms in non-clinical youth: A meta-analytic review

This review examined evidence for some core predictions of the response styles theory (RST) concerning the relation between response styles and symptoms of depression and gender differences in the use of response styles in non-clinical children and adolescents. In summarizing the literature, effect sizes (pooled correlation coefficients) were calculated for cross-sectional and longitudinal studies. Stability of the obtained effect sizes was evaluated by means of a fail-safe N analysis. Results indicated that stable and significant effect sizes were found for rumination being associated with concurrent and future levels of depression. When controlling for baseline levels of depression, effect sizes for rumination and distraction were not stable, indicating that these findings should be interpreted with considerable caution. Finally, significant and stable effect sizes for gender differences in response styles were found only for rumination among adolescents. Taken together, the findings partly support the predictions of the response styles theory examined in this meta-analysis and may implicate that rumination is a cognitive vulnerability factor for depressive symptoms among adolescents.     

Dysfunctional connectivity patterns in chronic heroin users: An fMRI study

Recent functional neuroimaging studies have examined cognitive inhibitory control, decision-making and stress regulation in heroin addiction using a cue-reactivity paradigm. Few studies have considered impairments in heroin users from an integrated perspective for evaluation of their brain functions. We hypothesized that the brain regions that are dysregulated in the chronic heroin users during cue-reactivity studies may also show dysfunctional connectivity in memory, inhibition and motivation-related dysfunctions during a resting state free of cues. The present study used resting functional magnetic resonance imaging (fMRI) to compare the interaction of brain regions between 12 chronic heroin users and 12 controls by employing a novel graph theory analysis (GTA) method. As a data-driven approach, GTA has the advantage of evaluating the strength as well as the temporal and spatial patterns of interactions among the brain regions. Abnormal topological properties were explored in the brain of chronic heroin users, such as the dysfunctional connectivity in the prefrontal cortex, ACC, SMA, ventral striatum, insula, amygdala and hippocampus. Our results suggest that GTA is a useful tool in defining dysregulated neural networks even during rest. This dysfunctional brain connectivity may contribute to decrease self-control, impaired inhibitory function as well deficits in stress regulation in chronic heroin users.     

The common magnitude code underlying numerical and size processing for action but not for perception

The interaction between numbers and action-related process has received increasing attention in the literature of numerical cognition. In the current study, two dual-task experiments were conducted to explore the interaction among numerical, prehension, and perceptual color/size judgments. The results revealed the commonality and distinctness of the magnitude representations that are involved in these tasks. Specifically, a photograph of a graspable object with a superimposed Arabic digit was presented in each trial. Participants were required to first judge the parity of the digit with a manual response while simultaneously planning a subsequent vocal response pertaining to the depicted object. When parity and action judgments were performed close in time, the compatibility effect between the numerical magnitude of the digit and the appropriate action (pinch vs. clutch) for the object was demonstrated in both manual and vocal responses. In contrast, such compatibility effect was absent when parity judgment was coupled with color-related or perceptual size judgment. The findings of the current study support the existence of a common magnitude code underlying numerical and non-numerical dimensions for action-related purposes, as proposed by the ATOM model (Walsh in Trends Cogn Sci 7:483–488, 2003). Furthermore, based on the selective presence of the compatibility effect, we argue that the interaction among different quantity dimensions conforms to the “dorsal-action and ventral-perception” organizational principle of the human brain.