Precomputed Radiative Heat Transport for Efficient Thermal Simulation.

Architectural design and urban planning are complex design tasks. Predicting the thermal impact of design choices at interactive rates enhances the ability of designers to improve energy efficiency and avoid problematic heat islands while maintaining design quality. We show how to use and adapt methods from computer graphics to efficiently simulate heat transfer via thermal radiation, thereby improving user guidance in the early design phase of large-scale construction projects and helping to increase energy efficiency and outdoor comfort. Our method combines a hardware-accelerated photon tracing approach with a carefully selected finite element discretization, inspired by precomputed radiance transfer. This combination allows us to precompute a radiative transport operator, which we then use to rapidly solve either steady-state or transient heat transport throughout the entire scene. Our formulation integrates time-dependent solar irradiation data without requiring changes in the transport operator, allowing us to quickly analyze many different scenarios such as common weather patterns, monthly or yearly averages, or transient simulations spanning multiple days or weeks. We show how our approach can be used for interactive design workflows such as city planning via fast feedback in the early design phase.

Deficient interference control during working memory updating in adults with ADHD: An event-related potential study.

OBJECTIVE: Little is known about the underlying mechanisms of poor working memory (WM) performance of adults with attention deficit hyperactivity disorder (ADHD). This study investigates interference and load effects during WM updating by use of event-related potentials. METHOD: Forty ADHD patients and 41 controls performed verbal n-back tasks under conditions of low and high WM load. Intrusion probes, i.e., lures, were implemented to challenge interference control abilities during WM processing. RESULTS: Stimulus-dependent N200 amplitude modulation and behavioral performance in lure trials were reduced in adults with ADHD compared to healthy controls. Also, P300 amplitudes tended to be less sensitive to WM load in patients with ADHD. CONCLUSION: Our findings provide electrophysiological evidence for inaccurate discrimination of stimulus categories. Particularly, deficient interference control may lead to overt WM deficits in adult subjects with ADHD. SIGNIFICANCE: The current findings contribute to a deeper understanding of the neural substrates of executive dysfunction in adult ADHD, focusing on the domain of WM.

Dimensional structure of bodily panic attack symptoms and their specific connections to panic cognitions, anxiety sensitivity and claustrophobic fears.

BACKGROUND: Previous studies of the dimensional structure of panic attack symptoms have mostly identified a respiratory and a vestibular/mixed somatic dimension. Evidence for additional dimensions such as a cardiac dimension and the allocation of several of the panic attack symptom criteria is less consistent. Clarifying the dimensional structure of the panic attack symptoms should help to specify the relationship of potential risk factors like anxiety sensitivity and fear of suffocation to the experience of panic attacks and the development of panic disorder. METHOD: In an outpatient multicentre study 350 panic patients with agoraphobia rated the intensity of each of the ten DSM-IV bodily symptoms during a typical panic attack. The factor structure of these data was investigated with nonlinear confirmatory factor analysis (CFA). The identified bodily symptom dimensions were related to panic cognitions, anxiety sensitivity and fear of suffocation by means of nonlinear structural equation modelling (SEM). RESULTS: CFA indicated a respiratory, a vestibular/mixed somatic and a cardiac dimension of the bodily symptom criteria. These three factors were differentially associated with specific panic cognitions, different anxiety sensitivity facets and suffocation fear. CONCLUSIONS: Taking into account the dimensional structure of panic attack symptoms may help to increase the specificity of the associations between the experience of panic attack symptoms and various panic related constructs.

Electrophysiological indices of error monitoring in juvenile and adult attention deficit hyperactivity disorder (ADHD)--a meta-analytic appraisal.

Attempts to identify the central disturbed processes explaining the overt symptoms of juvenile and adult ADHD rely heavily on the concept of deficient error monitoring processes. A number of studies have investigated event-related potentials (ERPs) and behavioral performance in tasks traditionally used to probe the interference control and inhibition of motor responses. The inspection of the error negativity (Ne/ERN) and error positivity (Pe) components evoked in these tasks has produced conflicting results with respect to the nature and extent of an error monitoring deficit in ADHD. A meta-analytic aggregation of these single studies should help develop a reliable appraisal of the evidence for the compromised performance monitoring processes in ADHD. Our meta-analysis was confined to studies of adult and juvenile ADHD participants examined in GoNogo and Flanker task studies that also reported the Ne/ERN and Pe ERP components. Only seven studies were suited for the meta-analysis, but their aggregation nevertheless led to clear results: Ne was attenuated in adult and adolescent ADHD participants for both tasks, and Pe was attenuated only in the GoNogo tasks. The ADHD participants made more errors than the controls in both tasks but responded slower only in the Flanker task. To our knowledge, this meta-analysis is the first to compare electrophysiological and behavioral indices of error monitoring in adult and juvenile ADHD patients and healthy controls. Admittedly, the data available for this comparison were sparse and heterogeneous; nevertheless, this meta-analysis produced salient results that indicate a monitoring deficit as a central feature of the ADHD syndrome.

Long-term cognitive and emotional consequences of mild traumatic brain injury.

BACKGROUND: The objective of this study was to investigate long-term cognitive and emotional sequelae of mild traumatic brain injury (mTBI), as previous research has remained inconclusive with respect to their prevalence and extent. METHOD: Thirty-three individuals who had sustained mTBI on average 6 years prior to the study and 33 healthy control subjects were matched according to age, gender and education. Structural brain damage at time of testing was excluded by magnetic resonance imaging (MRI). A comprehensive neuropsychological test battery was conducted to assess learning, recall, working memory, attention and executive function. Psychiatric symptoms were assessed by the Structured Clinical Interview for DSM-IV Axis I Disorders (SCID-I) and the Beck Depression Inventory (BDI). Possible negative response bias was ruled out by implementing the Word Memory Test (WMT). RESULTS: The mTBI individuals had significant impairments in all cognitive domains compared to the healthy control subjects. Effect sizes of cognitive deficits were medium to large, and could not be accounted for by self-perceived deficits, depression, compensation claims or negative response bias. BDI scores were significantly higher in the patient group, and three patients fulfilled DSM-IV criteria for a mild episode of major depression. CONCLUSIONS: Primarily, well-recovered individuals who had sustained a minor trauma more than half a decade ago continue to have long-term cognitive and emotional sequelae relevant for everyday social and professional life. mTBI may lead to a lasting disruption of neurofunctional circuits not detectable by standard structural MRI and needs to be taken seriously in clinical and forensic evaluations.

The Chemical Odor Sensitivity Scale: reliability and validity of a screening instrument for idiopathic environmental intolerance.

OBJECTIVE: The objective of this study was to examine the psychometric qualities of a brief screening measure for idiopathic environmental intolerance (IEI), the Chemical Odor Sensitivity Scale (COSS). METHODOLOGY: The COSS was administered together with other measures of environmental sensitivity, IEI, and symptom scales in large samples (students, individuals with IEI, and individuals without IEI). RESULTS: The COSS achieved high internal consistency (.88 < or = Cronbach's alpha < or = .96) and good factorial, convergent, and discriminant validity across diverse samples. In a longitudinal sample, the COSS and other IEI features were stable across time. According to receiver operating characteristic analyses, the COSS performs adequately in screening individuals likely to meet case criteria for IEI. CONCLUSIONS: The favorable psychometric qualities of the COSS recommend the scale as a useful tool both for assessing self-reported chemical odor sensitivity as a vulnerability marker and for screening for IEI.

Effects of improved glycaemic control maintained for 3 months on cognitive function in patients with Type 2 diabetes.

BACKGROUND AND AIM: In a previous study we failed to find beneficial short-term effects of improved glycaemic control on cognitive functioning in patients with Type 2 diabetes mellitus. A subgroup of the entire sample was tested again to examine the effect of longer-lasting improvement of metabolic control on cognitive functioning. METHODS: The cognitive performance of 26 patients with Type 2 diabetes was assessed at baseline and 3 months after discharge. Thirteen controls were tested at the similar time-points. Attention/concentration, psychomotor speed, verbal fluency, verbal memory and depressive symptoms were assessed. Improved glycaemic control was generally achieved with insulin therapy (20/26). RESULTS: At baseline, there was a trend for diabetic patients to perform worse than controls. Both groups improved significantly over 3 months in several measures. However, diabetic patients did not improve more than controls. CONCLUSIONS: In individuals with long-standing Type 2 diabetes, previous reports of improved cognitive capacity following restoration and maintenance of near-normoglycaemia were not confirmed. This might relate to the type of anti-diabetic therapy.

[Is premature termination of opiate detoxification due to intensive withdrawal or craving?]. / Sind Abbrüche im methadongestützten Opiatentzug bedingt durch Entzugssymptomatik oder Suchtmittelverlangen?

Opiate addicts terminate inpatient detoxification prematurely in about 50% of treatment episodes. Premature termination of treatment is often considered to be motivated by intensive withdrawal symptoms. Therefore, the relation between discontinuing treatment and the intensity of withdrawal symptoms and heroin craving is investigated. 130 opiate addicts consecutively admitted to a detoxification ward daily assessed the intensity of withdrawal symptoms on the Short Opiate Withdrawal Scale (SOWS) as well as the intensity of heroin craving on a visual analogue scale. Withdrawal symptoms were treated by stepwise reduction of methadone and symptom-oriented medication. 66 patients (50.8%) terminated treatment prematurely. However, during the days preceding treatment termination, these patients did not differ from regularly detoxified patients assessed on corresponding days with respect to craving, and reported even less intensity of withdrawal symptoms. In conclusion, neither the intensity of withdrawal symptoms nor the intensity of heroin craving constitutes the primary reason for premature termination of detoxification.

[Ill due to amalgam? 10 rules for managing the symptomatic patient]. / Krank durch Amalgam? Zehn Regeln für den Umgang mit Betroffenen.

Over the past two decades, mercury released by amalgam fillings has been held responsible for a number of mental and somatic health complaints. However, a systematic relation between increased mercury levels and the severity of the reported symptoms has never been demonstrated in any of the present well-controlled multidisciplinary studies. These studies, however, have found a high prevalence of mental disorders, especially somatization syndromes, among patients with self-diagnosed "amalgam illness". Additionally, our own studies indicate that amalgam anxiety is often merely one aspect of a general environmental anxiety. Overall, the present findings suggest a psychological etiology for amalgam-related complaints. Our psychosomatic model of "amalgam illness" integrates external factors, individual predispositions and specific processes of perception, awareness, evaluation and attribution. Practical management strategies for primary care physicians can be derived from this model.

Short-term effects of improved glycemic control on cognitive function in patients with type 2 diabetes.

BACKGROUND: According to numerous studies, type 2 diabetes is associated with mild cognitive dysfunction, and there is some evidence suggesting favorable effects of improved metabolic control on the mental capability of elderly diabetic patients. OBJECTIVE: To compare patients with type 2 diabetes to normal controls with respect to cognitive performance and to investigate the consequences of glycemic adjustment. METHODS: 53 patients with type 2 diabetes, most of them in secondary failure on oral antidiabetic drugs, but free from conditions which may cause brain dysfunction, were included (mean age 58.8 +/- 6.1 years, duration of disease 12.0 +/- 6.4 years). They were examined prior to (t1), and following (t2) glycemic adjustment with a time interval of approximately 2 weeks. 29 non-diabetic controls, comparable with regard to age, gender, education and verbal intelligence were examined twice with a corresponding time interval. Cognitive performance was assessed by well-standardized tests with a focus on attention/concentration, psychomotor speed, verbal fluency and verbal memory; mood status by two self-rating scales. Restoration of glycemic control included insulin treatment in the majority of patients (46/53). RESULTS: Diabetic subjects scored significantly lower in all cognitive tests used, while they did not differ from controls in mood status. From t1 to t2 they improved in those tests measuring attention/concentration, and psychomotor speed. With regard to similar changes in controls, we interpret these improvements as practice effects rather than the consequence of altered metabolic control. CONCLUSION: In a sample of patients with long-standing type 2 diabetes we could not confirm previous reports of improved cognitive capacity with restoration of glycemic control. Further studies on the effects of changes in control of blood glucose on cognitive performance in type 2 diabetes should be conducted with special regard to drugs used to lower blood glucose.

Implicit memory in schizotypal subjects and normal controls: effects of a secondary task on sequence learning.

Using a serial reaction-time task, the implicit memory performances of 29 high scoring (schizotypes) and 24 low scoring subjects (controls) on the German version of the 1997 Schizotypal Personality Questionnaire by Klein, Andresen, and Jahn were compared. To test the hypothesis that schizotypes show a differential deficit, subjects participated either in a single task condition of the serial reaction-time task or in a dual task condition of a secondary tone-counting task. Neither under single task conditions nor under dual task conditions did schizotypes show any impairment of implicit memory compared with controls. In addition, a separate analysis of the response latencies for the unique and ambiguous transitions of the repeated sequence did not indicate any differences between the two groups. These findings support and augment the results reported by Ferraro and Okerlund (1995).

Adverse health effects related to mercury exposure from dental amalgam fillings: toxicological or psychological causes?

BACKGROUND: Possible adverse health effects due to mercury released by amalgam fillings have been discussed in several studies of patients who attribute various symptoms to the effects of amalgam fillings. No systematic relation of specific symptoms to increased mercury levels could be established in any of these studies. Thus, a psychosomatic aetiology of the complaints should be considered and psychological factors contributing to their aetiology should be identified. METHODS: A screening questionnaire was used to identify subjects who were convinced that their health had already been affected seriously by their amalgam fillings (N = 40). These amalgam sensitive subjects were compared to amalgam non-sensitive subjects (N = 43). All participants were subjected to dental, general health, toxicological and psychological examinations. RESULTS: The two groups did not differ with respect to the number of amalgam fillings, amalgam surfaces or mercury levels assessed in blood, urine or saliva. However, amalgam sensitive subjects had significantly higher symptom scores both in a screening instrument for medically unexplained somatic symptoms (SOMS) and in the SCL-90-R Somatization scale. Additionally, more subjects from this group (50% versus 4.7%) had severe somatization syndromes. With respect to psychological risk factors, amalgam sensitive subjects had a self-concept of being weak and unable to tolerate stress, more cognitions of environmental threat, and increased habitual anxiety. These psychological factors were significantly correlated with the number and intensity of the reported somatic symptoms. CONCLUSIONS: While our results do not support an organic explanation of the reported symptoms, they are well in accord with the notion of a psychological aetiology of the reported symptoms and complaints. The findings suggest that self-diagnosed 'amalgam illness' is a label for a general tendency toward somatization.

Autonomic reactivity to mental stressors after single administration of lorazepam in male alcoholics and healthy controls.

Clinically unaffected sons of male alcoholics differ from controls without a family history of alcoholism in two respects: increased autonomic reactivity to aversive as well as non-aversive stimuli and increased attenuation of these responses by alcohol. This pattern of autonomic hyper-reactivity and alcohol-induced stress response dampening (SRD) might be a trait marker of genetic vulnerability and is often interpreted in terms of a diathesis stress model of alcohol dependence. Forty-five alcohol-dependent men (mean age: 39.20 years) and 37 healthy controls (mean age: 35.03 years) participated in a double-blind cross-over study in two experimental sessions each. The benzodiazepine lorazepam was selected as an alcohol substitute. Autonomic reactivity and lorazepam-induced SRD were assessed during incentive and non-incentive reaction time tasks as well as mental arithmetics. Alcohol-dependent men showed elevated resting heart rate levels and increased number of non-specific electrodermal responses. Evidence for autonomic hyper-reactivity was found for a subgroup of alcoholics with a family history of alcoholism.

An event-related brain potential substrate of disturbed response monitoring in paranoid schizophrenic patients.

Response monitoring in schizophrenic patients and healthy controls was assessed by measuring performance and event-related brain potentials in the flanker priming task. Three visual-context conditions were construed: Flankers and targets pointed either into the same direction or into different directions. Stimuli without any response assignment were used as flankers in the neutral context condition. The schizophrenic patients were further subdivided into paranoid (n = 19) and nonparanoid (n = 10) patients and compared with healthy controls (n = 18). Performance scores revealed that the flankers induced a similar degree of distraction by visual context in all 3 groups. Although the schizophrenic patients showed normal error correction performance, the error negativity (NE) was significantly reduced in paranoid schizophrenic patients. The attenuation of the NE possibly reflects disturbed response monitoring in these patients.

N2, P3 and the lateralized readiness potential in a nogo task involving selective response priming.

Motor inhibition and its correlates in the event-related potential (ERP) are often studied in go/nogo tasks. However, go and nogo trials differ in their motor and their attentional requirements, rendering an interpretation of corresponding changes in ERP components difficult. As an alternative strategy to study motor inhibition, a hybrid choice-reaction go/nogo procedure involving selective response priming was used. Eighteen subjects performed the task. Response time (RT) and error measures as well as the lateralized readiness potential (LRP) indicated that responses were primed by flanker stimuli that were associated with one of the two possible responses. In nogo trials, selective response priming influenced the N2 amplitude whereas the P3 amplitude was unaffected. Because the N2 appeared irrespective of whether an erroneous response was correctable (in go trials) or not (in nogo trials), we conclude that the N2 reflects either the detection or the inhibition of an inappropriate tendency to respond.

N200 in the flanker task as a neurobehavioral tool for investigating executive control.

Event-related potentials were recorded in a flanker task using arrowheads pointing to the left or to the right as targets and as congruent or incongruent flanker stimuli using squares as neutral flanker stimuli. The onset of the flanker stimuli preceded that of the target stimuli by 100 ms. Lateralized readiness potentials showed response activation below execution threshold in correspondence to the information conveyed by the flanker stimuli. Exclusively, the incongruent flanker condition provoked a N2c, which evolved closely synchronized to the erroneous response. Graded response analyses separating incongruent trials with weak, medium, and strong incorrect response activation revealed that the N2c amplitude covaried with the magnitude of the erroneous response. The N2c in the incongruent compatibility condition of the flanker task thus corresponds to the avoidance of inappropriate responses, possibly reflecting the inhibition of automatically but erroneously primed responses. The results are compatible with studies of error correction, suggesting that efference monitoring is a constituent of executive control.

Selective attention and response competition in schizophrenic patients.

Visual distractibility was studied in schizophrenic patients. Subjects had to respond to target stimuli while they ignored the visual context, which was either congruent, neutral, or incongruent with respect to the target stimulus. Eighteen schizophrenic patients and 18 healthy subjects performed this flanker task. Schizophrenic patients did not show increased distractibility compared with healthy subjects, and both groups showed the same attenuation of visual context effects when the spatial distance between target and flanker stimuli was increased. The two groups showed the same amount of interference by incongruent visual context. Thus, schizophrenic patients did not show enhanced distractibility, spatial extension of attention, or response competition. When flanker and target stimuli were redundant, the responses of schizophrenic patients were less accelerated than those of healthy subjects.

Error-correcting behavior in schizophrenic patients.

According to Frith (1987) the positive symptoms of schizophrenic patients result from an impaired central monitoring of their own actions. For motor behavior, this impairment implies deficient corrections of erroneous movements. Several studies found that schizophrenic patients did correct erroneous movements less frequently than various control groups. In these studies, movement errors were induced by instructing subjects to alternate between moving a joystick towards a target or away from it. In our study, 27 chronic schizophrenic patients, 27 healthy and 18 alcoholic controls were subjected to a similar task. Spatial and symbolic compatibility between stimuli and responses were varied in order to induce errors. Schizophrenic patients responded more slowly and took more time to reverse wrong movements than both control groups. They did not show fewer error corrections or increased correction latencies. These results did not support the supposed deficit in central monitoring of action. Schizophrenic patients exhibited more short latency movements with multiple changes of movement direction than the control groups. This may indicate a failure to inhibit the initiation of competing responses.

Reaction time paradigms in subjects at risk for schizophrenia.

Deviant response patterns in experimental reaction time paradigms in schizophrenic probands are well documented. Although simple reaction times are strongly influenced by the current psychopathological status of the proband (e.g. florid psychotic patients versus remitted patients) these influences are less clear for measures obtained from more complex reaction time paradigms. These include the crossover paradigm (reaction time to stimuli presented after constant preparatory intervals in comparison to reaction time to stimuli presented after irregular preparatory intervals) and the modality shift paradigm (reaction time to a stimulus (light or tone) when the modality of the stimulus on the preceding trial was the same compared to when it was different). It is not clear if these peculiarities of response patterns occur as a consequence of the disease or if they represent vulnerability markers for schizophrenia. Both crossover reaction time and modality shift reaction time paradigms were applied to 56 drug free schizophrenics, 45 healthy siblings of these patients and 68 healthy controls. The results indicate that retarded reaction times and the occurrence of the crossover effect as well as of the modality shift effect distinguish schizophrenics and controls. Healthy siblings of schizophrenics differed from healthy controls with regard to the crossover effect but not with regard to the modality shift effect. Therefore only the crossover effect represents a vulnerability marker for schizophrenia. Correlations between the modality shift and the crossover effect revealed strong correlations in the schizophrenic group only.

Patient Rejection Scale: correlations with symptoms, social disability and number of rehospitalizations.

The Patient Rejection Scale (RPS), which was developed to assess rejecting attitudes and feelings of relatives toward mental patients, was administered to a German sample of 44 family members or significant others living with first-admitted schizophrenics. Both at admission (t0) and 6 months later (t6), the PRS was significantly correlated with the number of rehospitalizations during the first 3 years after admission. In comparison, the association between PRS scores and different measures of psychopathology during the 2-year follow-up period was weak. Thus, rejecting attitudes of patients' relatives seem to imply a higher risk of relapse without substantial medication by symptoms. We suspect that relatives with rejecting attitudes towards a patient might tend to apply for readmission more easily than more accepting relatives.