We study the impact of international long-distance flights on the global spatial allocation of economic activity. To identify causal effects, we exploit variation due to regulatory and technological constraints which give rise to a discontinuity in connectedness between cities at a distance of 6,000 miles. We show that improving an airport’s position in the network of air links has a positive effect on local economic activity, as captured by satellite-measured night lights. We find that air links increase business links, showing that the movement of people fosters the movement of capital. In particular, this is driven mostly by capital flowing from high-income to middle-income (but not low-income) countries. Taken together, our results suggest that increasing interconnectedness induces links between businesses and generates economic activity at the local level, but also gives rise to increased spatial inequality locally, and potentially globally.
Humans and other primates have evolved the ability to represent their status in the group's social hierarchy, which is essential for avoiding harm and accessing resources. Yet it remains unclear how the human brain learns dominance status and adjusts behavior accordingly during dynamic social interactions. Here we address this issue with a combination of fMRI and transcranial direct current stimulation (tDCS). In a first fMRI experiment, participants learned an implicit dominance hierarchy while playing a competitive game against three opponents of different skills. Neural activity in the rostromedial PFC (rmPFC) dynamically tracked and updated the dominance status of the opponents, whereas the ventromedial PFC and ventral striatum reacted specifically to competitive victories and defeats. In a second experiment, we applied anodal tDCS over the rmPFC to enhance neural excitability while subjects performed a similar competitive task. The stimulation enhanced the relative weight of victories over defeats in learning social dominance relationships and exacerbated the influence of one's own dominance over competitive strategies. Importantly, these tDCS effects were specific to trials in which subjects learned about dominance relationships, as they were not present for control choices associated with monetary incentives but no competitive feedback. Taken together, our findings elucidate the role of rmPFC computations in dominance learning and unravel a fundamental mechanism that governs the emergence and maintenance of social dominance relationships in humans.
Background Cognitive biases and personality traits (aversion to risk or ambiguity) may lead to diagnostic inaccuracies and medical errors resulting in mismanagement or inadequate utilization of resources. We conducted a systematic review with four objectives: 1) to identify the most common cognitive biases, 2) to evaluate the influence of cognitive biases on diagnostic accuracy or management errors, 3) to determine their impact on patient outcomes, and 4) to identify literature gaps. Methods We searched MEDLINE and the Cochrane Library databases for relevant articles on cognitive biases from 1980 to May 2015. We included studies conducted in physicians that evaluated at least one cognitive factor using case-vignettes or real scenarios and reported an associated outcome written in English. Data quality was assessed by the Newcastle-Ottawa scale. Among 114 publications, 20 studies comprising 6810 physicians met the inclusion criteria. Nineteen cognitive biases were identified. Results All studies found at least one cognitive bias or personality trait to affect physicians. Overconfidence, lower tolerance to risk, the anchoring effect, and information and availability biases were associated with diagnostic inaccuracies in 36.5 to 77 % of case-scenarios. Five out of seven (71.4 %) studies showed an association between cognitive biases and therapeutic or management errors. Of two (10 %) studies evaluating the impact of cognitive biases or personality traits on patient outcomes, only one showed that higher tolerance to ambiguity was associated with increased medical complications (9.7 % vs 6.5 %; p = .004). Most studies (60 %) targeted cognitive biases in diagnostic tasks, fewer focused on treatment or management (35 %) and on prognosis (10 %). Literature gaps include potentially relevant biases (e.g. aggregate bias, feedback sanction, hindsight bias) not investigated in the included studies. Moreover, only five (25 %) studies used clinical guidelines as the framework to determine diagnostic or treatment errors. Most studies (n = 12, 60 %) were classified as low quality. Conclusions Overconfidence, the anchoring effect, information and availability bias, and tolerance to risk may be associated with diagnostic inaccuracies or suboptimal management. More comprehensive studies are needed to determine the prevalence of cognitive biases and personality traits and their potential impact on physicians’ decisions, medical errors, and patient outcomes.
Striatal abnormalities play a crucial role in the pathophysiology of schizophrenia. Growing evidence suggests an association between aberrant striatal activity during reward anticipation and symptom dimensions in schizophrenia. However, it is not clear whether this holds across the psychosis continuum. The aim of the present study was to investigate alterations of ventral striatal activation during reward anticipation and its relationship to symptom expression in persons with schizotypal personality traits (SPT) and first-episode psychosis. Twenty-six individuals with high SPT, 26 patients with non-affective first-episode psychosis (including 13 with brief psychotic disorder (FEP-BPD) and 13 with first-episode schizophrenia [FEP-SZ]) and 25 healthy controls underwent event-related functional magnetic resonance imaging while performing a variant of the Monetary Incentive Delay task. Ventral striatal activation was positively correlated with total symptom severity, in particular with levels of positive symptoms. This association was observed across the psychosis continuum and within each subgroup. Patients with FEP-SZ showed the strongest elevation of striatal activation during reward anticipation, although symptom levels did not differ between groups in the psychosis continuum. While our results provide evidence that variance in striatal activation is mainly explained by dimensional symptom expression, patients with schizophrenia show an additional dysregulation of striatal activation. Trans-diagnostic approaches are promising in order to disentangle dimensional and categorical neural mechanisms in the psychosis continuum.
BACKGROUND A small but increasing number of studies suggest that non-invasive brain stimulation by means of transcranial direct current stimulation (tDCS) can modulate arithmetic processes that are essential for higher-order mathematical skills and that are impaired in dyscalculic individuals. However, little is known about the neural mechanisms underlying such stimulation effects, and whether they are specific to cognitive processes involved in different arithmetic tasks. METHODS We addressed these questions by applying tDCS during simultaneous functional magnetic resonance imaging (fMRI) while participants were solving two types of complex subtraction problems: repeated problems, relying on arithmetic fact learning and problem-solving by fact retrieval, and novel problems, requiring calculation procedures. Twenty participants receiving left parietal anodal plus right frontal cathodal stimulation were compared with 20 participants in a sham condition. RESULTS We found a strong cognitive and neural dissociation between repeated and novel problems. Repeated problems were solved more accurately and elicited increased activity in the bilateral angular gyri and medial plus lateral prefrontal cortices. Solving novel problems, in contrast, was accompanied by stronger activation in the bilateral intraparietal sulci and the dorsomedial prefrontal cortex. Most importantly, tDCS decreased the activation of the right inferior frontal cortex while solving novel (compared to repeated) problems, suggesting that the cathodal stimulation rendered this region unable to respond to the task-specific cognitive demand. CONCLUSIONS The present study revealed that tDCS during arithmetic problem-solving can modulate the neural activity in proximity to the electrodes specifically when the current demands lead to an engagement of this area.
Die Kosten unmittelbar vor dem Tod sind ein häufiges Thema in der gesundheitspolitischen Diskussion. Der vorliegende Artikel prüft verschiedene Hypothesen zum Verlauf dieser Kosten und zum Zusammenhang mit verschiedenen Eigenschaften
der Verstorbenen. Als Grundlage dient eine statistische Analyse von 14944 Todesfällen.
Welche Faktoren entscheiden darüber, dass ein Kundenwert letztendlich so eingeführt werden kann, dass der Verkauf ihn als strategisches Verkaufs-Instrument erfolgswirksam zu nutzen vermag? Zu nennen sind vorausschauende Planung, systematische Bestimmung der Anforderungen und sorgfältige, auf die Anforderungen abgestimmte mathematische Formulierung der Berechnung. Weiter stellen der zielgerichtete Einbezug eines Data-Warehouses, eine akkurate statistische Modellierung, rasche und umsichtige Implementierung und vor allem eine detaillierte und fundierte Schulung des Außendienstes durch Marketingmitarbeiter wichtige Erfolgskriterien dar. Nach der ersten Implementierung ist es wichtig, das Projekt noch nicht als abgeschlossen zu betrachten, denn noch fehlt der Feinschliff. Dazu gehört die selbstkritische Überprüfung und nötigenfalls Verbesserung der Berechnung, sowie die Optimierung der Berechnungsperiodizität. Die kontinuierliche Schulung muss ebenfalls beibehalten werden, damit der Feedback generierende Kontakt zum Außendienst nicht abbricht. Aber auch gezielte Kommunikation bei den strategischen Organen des Unternehmens ist notwendig, um die Akzeptanz des Kundenwerts auf allen hierarchischen Stufen sicher zu stellen. Die konsequente Beachtung all dieser Prozessschritte war der Grund dafür, dass die vorliegende Case Study zur Erfolgsgeschichte wurde.
The main objective of risk adjustment in systems of regulated competition on healthinsurance markets is the removal of incentives for undesirable risk selection. We introduce a simple conceptual framework to clarify how the definition of "acceptable costs" and the distinction between legitimate and illegitimate risk adjusters imply diffcult ethical trade-offs between equity, avoidance of undesirable risk selection and cost-effectiveness. Focusing on the situation in Belgium, Germany, Israel, the Netherlands and Switzerland, we show how differences in the importance attached to solidarity and in the beliefs about market effciency, have led to different decisions with respect to the definition of the basic benefits package, the choice of risk-adjusters, the possibilities of managed care, the degree of consumer choice and the relative importance of income-related financing sources in the overall system.
