The Effects of Acute Tryptophan Depletion on Reactive Aggression in Adults with Attention-Deficit/Hyperactivity Disorder (ADHD) and Healthy Controls

Background: The neurotransmitter serotonin (5-HT) has been linked to the underlying neurobiology of aggressive behavior, particularly with evidence from studies in animals and humans. However, the underlying neurobiology of aggression remains unclear in the context of attention-deficit/hyperactivity disorder (ADHD), a disorder known to be associated with aggression and impulsivity. We investigated the effects of acute tryptophan depletion (ATD), and the resulting diminished central nervous serotonergic neurotransmission, on reactive aggression in healthy controls and adults with ADHD. Methodology/Principal Findings: Twenty male patients with ADHD and twenty healthy male controls were subjected to ATD with an amino acid (AA) beverage that lacked tryptophan (TRP, the physiological precursor of 5-HT) and a TRPbalanced AA beverage (BAL) in a double-blind, within-subject crossover-study over two study days. We assessed reactive aggression 3.25 hours after ATD/BAL intake using a point-subtraction aggression game (PSAG) in which participants played for points against a fictitious opponent. Point subtraction was taken as a measure for reactive aggression. Lowered rates of reactive aggression were found in the ADHD group under ATD after low provocation (LP), with controls showing the opposite effect. In patients with ADHD, trait-impulsivity was negatively correlated with the ATD effect on reactive aggression after LP. Statistical power was limited due to large standard deviations observed in the data on point subtraction, which may limit the use of this particular paradigm in adults with ADHD

Baltic Sea wave conditions under climate change scenarios

Anthropogenic climate change can alter the wind- and sea-ice climate and thus the wave conditions in the Baltic Sea. Here, transient simulations with the 3rd generation wave model WAM under two IPCC AR4 emission scenarios (A1B and B1) and two initial conditions of the forcing atmospheric fields are analyzed for the period 1961–2100. Future changes in the wave climate comprise higher significant wave height for most regions and simulations. Median waves show temporal and spatial consistent changes, whereas extreme waves (99th percentile and maximum) show much more variability in space and among the simulations. These changes in the wave fields result from not only higher wind speeds but also from a shift to more westerly winds, which leads to different fetch and thus to different significant wave height and direction. The multi-decadal and the inter-simulation variability illustrate the uncertainty in the estimation of the climate change signal

Reconstruction of wind and surge of the 1906 storm tide at the German North Sea Coast

Abstract. Storm tides represent a major threat to the low-lying German North Sea coast. Knowledge of extremes is essential for the design of reliable and robust coastal defences. A storm tide that occurred on 12–13 March 1906 along the German Bight coastline still represents one of the strongest events on record. For this event, detailed knowledge of atmospheric and hydrodynamic conditions is still lacking. To assess the potential impact of such an event on today’s coastline, century-long atmospheric reanalysis data together with a manual synoptic reconstruction based on archived weather data were used to drive a tide-surge model and to simulate water levels during the event. Sensitivity experiments were performed to estimate potential amplification of water levels that could have been caused by different time lags between the storm and the astronomical tide. Comparison between the model results and the limited available observational data indicated, that the water levels could be reasonably reconstructed using wind fields from the manual synoptic approach and some of the reanalysis ensemble members. The amplification potential was found to be low because the storm occurred during spring tide and shifts in the phase of the astronomic tide yielded only small changes in total water levels. To summarize, if pressure data are available at relevant locations, historical storm surges can be simulated with reanalysis products and also with a manual synoptic reconstruction. </jats:p

Simulationen von historischen St&amp;#252;rmen und Sturmfluten in der Deutschen Bucht

&amp;lt;p&amp;gt;Sturmfluten sind gekennzeichnet durch das gleichzeitige Auftreten von Tidehochwasser und eines hohen Windstaus. Im letzten Jahrhundert gab es verschiedene schwere Sturmereignisse, die teilweise starke Sch&amp;amp;#228;den an den K&amp;amp;#252;sten der Deutschen Bucht verursachten.&amp;lt;/p&amp;gt; &amp;lt;p&amp;gt;Wir haben drei verschiedene historische Sturmereignisse herausgesucht, die sich in ihrer Zugbahn und Tide unterscheiden.&amp;lt;/p&amp;gt; &amp;lt;ul&amp;gt; &amp;lt;li&amp;gt;F&amp;amp;#252;r die ostfriesische Nordseek&amp;amp;#252;ste gilt die Sturmflut vom 13.03.1906 heute noch als Bemessungsgrundlage f&amp;amp;#252;r den K&amp;amp;#252;stenschutz. Bisher war es nicht m&amp;amp;#246;glich, mangels atmosph&amp;amp;#228;rischen Antriebsdaten, diese Sturmflut zu simulieren.&amp;lt;/li&amp;gt; &amp;lt;li&amp;gt;Der Sturm vom 10.02.1949 ereignete sich w&amp;amp;#228;hrend Tideniedrigwasser und erzeugte einen hohen Windstau. An der Pegelstation Husum wurde das h&amp;amp;#246;chste und in Cuxhaven das dritth&amp;amp;#246;chste Niedrigwasser gemessen.&amp;lt;/li&amp;gt; &amp;lt;li&amp;gt;Die schwere Sturmflut von 16./17.02.1962 verursachte starke Sch&amp;amp;#228;den an der deutschen Nordseek&amp;amp;#252;ste und Hamburg.&amp;lt;/li&amp;gt; &amp;lt;/ul&amp;gt; &amp;lt;p&amp;gt;&amp;amp;#160;&amp;lt;/p&amp;gt; &amp;lt;p&amp;gt;In unseren Untersuchungen haben wir folgende Fragestellungen behandelt:&amp;lt;/p&amp;gt; &amp;lt;ul&amp;gt; &amp;lt;li&amp;gt;K&amp;amp;#246;nnen mit den atmosph&amp;amp;#228;rischen Daten aus dem 20th Century Reanalysis Project die St&amp;amp;#252;rme simuliert werden?&amp;lt;/li&amp;gt; &amp;lt;li&amp;gt;K&amp;amp;#246;nnen wir mit einem hydrodynamischen Modell die Wasserst&amp;amp;#228;nde dieser Sturmereignisse simulieren?&amp;lt;/li&amp;gt; &amp;lt;li&amp;gt;Wieviel h&amp;amp;#246;her w&amp;amp;#228;re der Wasserstand, wenn die St&amp;amp;#252;rme bei Springtide stattgefunden h&amp;amp;#228;tte?&amp;lt;/li&amp;gt; &amp;lt;/ul&amp;gt; &amp;lt;p&amp;gt;&amp;amp;#160;&amp;lt;/p&amp;gt; &amp;lt;p&amp;gt;F&amp;amp;#252;r die Beantwortung dieser Fragen wurde das hydrodynamische TRIM-NP-Modell mit Druck- und Winddaten aus dem 20th Century Reanalysis Project (20CR) angetrieben und die daraus resultierenden Wasserst&amp;amp;#228;nde mit Messungen an Pegelstationen verglichen. An den seitlichen R&amp;amp;#228;ndern des TRIM-NP-Modells wurden Daten aus dem FES2004 Tide-Modell verwendet.&amp;lt;/p&amp;gt; &amp;lt;p&amp;gt;F&amp;amp;#252;r die Sturmflut von 1906 wurde eine synoptische Rekonstruktion basierend auf historische Druckdaten angefertigt und die Windgeschwindigkeit daraus berechnet.&amp;amp;#160;&amp;lt;/p&amp;gt; &amp;lt;p&amp;gt;Erste Ergebnisse zeigen, dass f&amp;amp;#252;r die einzelnen Sturmereignisse die Wasserst&amp;amp;#228;nde, angetrieben durch einzelne Ensemble Member aus 20CR-Reanalysedaten, gut mit den Messungen &amp;amp;#252;bereinstimmen. Durch die Verschiebung der Tide erh&amp;amp;#246;hen sich die Wasserst&amp;amp;#228;nde f&amp;amp;#252;r die Sturmereignisse 1949 und 1962 um einige Dezimeter, das hei&amp;amp;#223;t, dass die Sturmfluten h&amp;amp;#228;tten noch h&amp;amp;#246;her auflaufen k&amp;amp;#246;nnen. &amp;amp;#160;&amp;amp;#160;&amp;lt;/p&amp;gt; &amp;lt;p&amp;gt;&amp;amp;#160;&amp;lt;/p&amp;gt; &amp;lt;p&amp;gt;---------&amp;lt;/p&amp;gt; &amp;lt;p&amp;gt;Die Sturmflut im M&amp;amp;#228;rz 1906&amp;lt;/p&amp;gt; &amp;lt;p&amp;gt;https://www.dkrz.de/de/projekte-und-partner/HLRE-Projekte/focus/sturmflut1906&amp;lt;/p&amp;gt;</jats:p

Mental health and hearing impairment - A German survey

IntroductionOnly few international studies have focused on mental diseases among the hearing-impaired population. However, Fellinger et al. (2012) underline the high discrepancy between the current and future demand of mental treatment and the simultaneous impeded access to health care.AimsThe aim of this multicenter project is to conduct the first analysis of mental diseases among the hearing-impaired population in Germany in order to quantify and qualify the specific demands of treatment.ObjectivesIn order to achieve this aim, we compiled an extensive questionnaire battery.MethodsThis questionnaire battery measured sociodemographic data, non-verbal intelligence, quality of life, perception and suffering from stress, psychosomatic symptoms as well as personality traits.ResultsOur three samples consisted of 21 hearing-impaired patients with a history of mental diseases (EG-HI), 21 hearing-impaired subjects without mental diseases (CG-HI) and 21 hearing participants without any psychological disease (CG-H). Compared to the two control groups, the EG-HI shows significantly higher rates in different fields, i.e. participants perceive a lower quality of life, suffer from more psychosomatic symptoms and show more pronounced personality traits. The two control groups did not differ significantly from each other.ConclusionsCertain psychological characteristics among hearing-impaired patients can be detected which need to be accounted for in treatment. Furthermore, a hearing impairment is not inevitably linked to a reduced quality of life or even mental disorders. Therefore, future research should focus on risk factors and protective factors which could prevent mental diseases among the hearing-impaired population.Disclosure of interestThe authors have not supplied their declaration of competing interest.</jats:sec

A diminished serotonin level influences the performance in a modified AX-continuous performance task in adult ADHD

IntroductionAttention deficit disorder (ADHD) is a psychiatric disorder, which is characterized by deficits of executive functions (EF) and impulsivity. Whereas a variety of studies on the involvement of the dopaminergic system in ADHD exists, the impact of the serotonergic system to EF in ADHD in adults is underinvestigated.AimsTo ascertain the effects of rapid tryptophan depletion (RTD) and the resultant reduction of the central nervous levels of serotonin on the EF of male adult patients with ADHD.Methods20 ADHD patients and 20 healthy controls completed the RTD test on one day and a placebo on another day in a double-blind within subject crossover design.- In addition, the subtest alertness of the TAP and a modified Version of the Continuous performance test (AX-CPT) with three stimulus conditions (AX, AY, BX) were administered.ResultsStatistical analysis revealed significant shorter reaction times, more errors and more omission errors in the ADHD group in the AX-CPT. The omissions error rate increased in both groups in the RTD condition but not in the placebo condition. Statistical analyses did not yield any significant differences between groups in the subtest alertness and no significant interaction of group and effect of the RTD condition could be observed.ConclusionsIn addition to higher impulsivity of patients with ADHD as reflected by shorter reaction times and higher error rates, the results of the present study imply an involvement of the serotonergic system as reflected by RTD in sustained and selective attention.</jats:sec

Modelling austenite flow curves in low alloy and microalloyed steels

A model has been developed to predict the austenite flow curves of low alloy and microalloyed steels. The model consists basically of two expressions for stress, as a function of strain, temperature, strain rate and the chemical composition of the steel. The first predicts the hardening and dynamic recovery region and the second predicts the softening caused by dynamic recrystallization, the algebraic sum of both expressions predicting the complete flow curve. The model's different parameters are a function of the dimensionless parameter of Sellars and Tegart's equation, which in turn has been modelled not only as a function of temperature and strain rate but also as a function of the chemical composition. In this way one single model may be applied to any hot deformed steel whose composition is the same as or similar to those studied.This work has been undertaken in CENIM (Madrid) and the authors are grateful for the financial support of the DGICYT of Spain (Project PB89-0022). Hernandez’s studies are sponsored by the UNAM (México).Peer reviewe