Climatic warming: a trigger for glacial iceberg surges (‘Heinrich events’) in the North Atlantic?

In the present-day western North Atlantic, icebergs can be observed off north-east Canada, drifting south along the coast in the cold Labrador Current. Normally they melt in the area off Newfoundland where they reach warmer waters. Most of these icebergs originate from calving glaciers in West Greenland or in the Canadian Arctic. Jakobshavn Isbræ in West Greenland (Fig. 1) deserves particular mention as it is the fastest known ice stream in the world draining 6–7% of the entire Greenland ice sheet (Joughin et al. 2004). Southward drifting icebergs also occur along the east coast of Greenland (Fig. 2), but most of these melt when they approach the southernmost tip of Greenland. The iceberg limit in the north-western Atlantic varies from year to year, but isolated icebergs may reach far south of Newfoundland (Fig. 1). Many icebergs carry a load of rock debris and soil incorporated by their parent glacier that leads to deposition of ice rafted debris on the deep ocean sea floor. In the past decade the Geological Survey of Denmark and Greenland (GEUS) has initiated marine geological investigations in the North Atlantic on the late Quaternary variability of North Atlantic thermohaline circulation, with special focus on the possible link between climate change and variations in deep-water flow intensity (Kuijpers et al. 1998, 2002, 2003). Moreover, glaciological projects in Greenland undertaken by GEUS have significantly contributed to the current debate of present-day climatic warming. Notably work carried out in East Greenland fjords has provided crucial information relevant for the study of glacial iceberg surges in the North Atlantic (Reeh et al. 1999). These surges are suggested to have been triggered under the influence of extreme cold climate conditions, but the actual trigger mechanism involved has been a matter of much debate. Evidence from modern glacier process studies referred to above, combined with results of recent studies in the North Atlantic carried out by GEUS and partner institutions, has provided new insights into the possible trigger mechanism of these massive glacial iceberg surges. These new findings have great significance for the current climate debate, since they strongly suggest that ongoing ocean warming can trigger a sudden, massive break-up of ice shelves. Such processes may already be in progress in the Arctic (e.g. Vincent et al. 2004), where rapid ice-shelf disruption on the margin of the Canadian Arctic Ocean has been reported to be the result of significant warming over the past few decades. During this period intensified inflow of Atlantic water to the Eurasian sector of the Arctic has been noted. It is evident that for Antarctic ice shelves large-scale disruption and break-up may lead to significant destabilisation of the Antarctic ice sheet with the serious risk of a sudden, drastic sea-level rise

Response inhibition deficits in externalizing child psychiatric disorders: An ERP-study with the Stop-task

BACKGROUND: Evidence from behavioural studies suggests that impaired motor response inhibition may be common to several externalizing child psychiatric disorders, although it has been proposed to be the core-deficit in AD/HD. Since similar overt behaviour may be accompanied by different covert brain activity, the aim of this study was to investigate both brain-electric-activity and performance measures in three groups of children with externalizing child psychiatric disorders and a group of normal controls. METHODS: A Stop-task was used to measure specific aspects of response inhibition in 10 children with attention-deficit hyperactivity disorder (AD/HD), 8 children with oppositional defiant disorder/conduct disorder (ODD/CD), 11 children with comorbid AD/HD+ODD/CD and 11 normal controls. All children were between 8 and 14 years old. Event-related potentials and behavioural responses were recorded. An initial go-signal related microstate, a subsequent Stop-signal related N200, and performance measures were analyzed using ANCOVA with age as covariate. RESULTS: Groups did not differ in accuracy or reaction time to the Go-stimuli. However, all clinical groups displayed reduced map strength in a microstate related to initial processing of the Go-stimulus compared to normal controls, whereas topography did not differ. Concerning motor response inhibition, the AD/HD-only and the ODD/CD-only groups displayed slower Stop-signal reaction times (SSRT) and Stop-failure reaction time compared to normal controls. In children with comorbid AD/HD+ODD/CD, Stop-failure reaction-time was longer than in controls, but their SSRT was not slowed. Moreover, SSRT in AD/HD+ODD/CD was faster than in AD/HD-only or ODD/CD-only. The AD/HD-only and ODD/CD-only groups displayed reduced Stop-N200 mean amplitude over right-frontal electrodes. This effect reached only a trend for comorbid AD/HD+ODD/CD. CONCLUSION: Following similar attenuations in initial processing of the Go-signal in all clinical groups compared to controls, distinct Stop-signal related deficits became evident in the clinical groups. Both children with AD/HD and ODD/CD showed deficits in behavioural response-inhibition accompanied by decreased central conflict signalling or inhibition processes. Neither behavioural nor neural markers of inhibitory deficits as found in AD/HD-only and ODD/CD-only were additive. Instead, children with comorbid AD/HD+ODD/CD showed similar or even less prominent inhibition deficits than the other clinical groups. Hence, the AD/HD+ODD/CD-group may represent a separate clinical entity

Worin unterscheiden sich die mit verschiedenen regionalen Klimamodellen berechneten möglichen zukünftigen Änderungen der Windfelder auf der Nordsee

KlimawandelEine mögliche zukünftige Änderung der Windgeschwindigkeiten auf der Nordsee ist von großer Bedeutung für die Schifffahrt und die Sicherheit der Küsten. Deshalb wurden im BMVI-Forschungsprogramm KLIWAS (Auswirkungen des Klimawandels auf Wasserstraßen und Schifffahrt – Entwicklung von Anpassungsoptionen) Windfelder auf der Nordsee untersucht. Zur Analyse der bodennahen Windfelder wurden Ergebnisse mehrerer regionaler Klimamodelle für den Zeitraum 1950 – 2100 ausgewertet. Um regionale Unterschiede darzustellen, erfolgte eine Aufteilung der Nordsee in sechs Gebiete. Die zeitlichen Änderungen der mittleren und hohen Windgeschwindigkeiten wurden anhand des 50. und 99. Perzentils jährlicher Häufigkeitsverteilungen untersucht. Dabei wurden die Häufigkeitsverteilungen sowohl an Modellgitterpunkten als auch in den sechs Nordsee-Gebieten bestimmt. Aus den Perzentilen der jährlichen Verteilungen wurden Zeitreihen von 1951 – 2099 gebildet. Die Ergebnisse aller untersuchten Klimamodellläufe wurden in Bezug auf Gemeinsamkeiten und Unterschiede untersucht. Die Werte der Perzentile der jährlichen Verteilungen aller Modellläufe zeigen sämtlich eine hohe Variabilität von Jahr zu Jahr. Die 30-jährigen gleitenden Mittel der Perzentilzeitreihen weisen dekadische Oszillationen auf, wobei die höchsten Mittelwerte meist nicht am Ende des 21. Jahrhunderts beobachtet werden. Die linearen Trends der Zeitreihen sowohl des 50. als auch des 99. Perzentiles weisen in keiner der untersuchten Regionen einheitliche Vorzeichen für alle Modellergebnisse auf

1Controlled evaluation of a neurofeedback training of slow cortical potentials in children with Attention Deficit/Hyperactivity Disorder (ADHD)

BACKGROUND: Although several promising studies on neurofeedback training in Attention Deficit/Hyperactivity Disorder (ADHD) have been performed in recent years, the specificity of positive treatment effects continues to be challenged. METHODS: To evaluate the specificity of a neurofeedback training of slow cortical potentials, a twofold strategy was pursued: First, the efficacy of neurofeedback training was compared to a group training program for children with ADHD. Secondly, the extent of improvements observed in the neurofeedback group in relation to successful regulation of cortical activation was examined. Parents and teachers rated children's behaviour and executive functions before and after treatment. In addition, children underwent neuropsychological testing before and after training. RESULTS: According to parents' and teachers' ratings, children of the neurofeedback training group improved more than children who had participated in a group therapy program, particularly in attention and cognition related domains. On neuropsychological measures children of both groups showed similar improvements. However, only about half of the neurofeedback group learned to regulate cortical activation during a transfer condition without direct feedback. Behavioural improvements of this subgroup were moderately related to neurofeedback training performance, whereas effective parental support accounted better for some advantages of neurofeedback training compared to group therapy according to parents' and teachers' ratings. CONCLUSION: There is a specific training effect of neurofeedback of slow cortical potentials due to enhanced cortical control. However, non-specific factors, such as parental support, may also contribute to the positive behavioural effects induced by the neurofeedback training

Развитие системы управления теплоэнергетической отраслью в регионе

Объектом исследования является – система управления теплоэнергетической отраслью в регионе. Цель работы - разработка подходов к выявлению, анализу и разрешению проблем, препятствующих эффективному развитию системы управления в теплоэнергетике. В процессе исследования проводился анализ зарубежных и отечественных систем управления и практического опыта реализации моделей управления в энергетической и теплоэнергетической отрасли.The object of study is the control system of thermal power industry in the region. The aim of this work is to develop approaches to the identification, analysis and resolution of problems impeding the effective development of the management system in power. In the process of investigation the analysis of foreign and domestic control systems and practical experience in the implementation of management models in the energy and power industry