Impulsivity and the 5-HTTLPR Polymorphism in a Non-Clinical Sample

BACKGROUND: Impulsivity has been associated with serotonergic system functions. However, few researchers have investigated the relationship between a polymorphism in the promoter of the serotonin transporter gene (5-HTTLPR) and the different components of impulsivity in a non-clinical population. The aim of this study was to investigate the relationship between a polymorphism in the promoter region of the serotonin transporter gene (5-HTTLPR) and the different components of impulsivity in a non-clinical population. METHODOLOGY/PRINCIPAL FINDINGS: We administered two neuropsychological tests, the Continuous Performance Task and the Iowa Gambling Task, to 127 healthy participants to measure their levels of motor, attentional and non-planning impulsivity. Then, these participants were grouped by genotype and gender, and their scores on impulsivity measures were compared. There were no significant differences between group scores on attentional, motor and non-planning impulsivity. CONCLUSIONS/SIGNIFICANCE: Our results suggest that 5-HTTLPR genotype is not significantly associated with subsets of impulsive behavior in a non-clinical sample when measured by neuropsychological tests. These findings are discussed in terms of the sensitivity of neuropsychological tests to detect impulsivity in a non-clinical population and the role of gender and race in the relationship between the 5-HTTLPR and impulsivity

Naturally propped fractures caused by quartz cementation preserve oil reservoirs in basement rocks

MB is in receipt of a postgraduate studentship from PTDF (Nigeria). Skilled technical support was provided by M. Baron and J. Still. Two reviewers made valuable criticisms that improved the paper.Peer reviewedPostprin

Serotonin, genetic variability, behaviour, and psychiatric disorders - a review

Brain monoamines, and serotonin in particular, have repeatedly been shown to be linked to different psychiatric conditions such as depression, anxiety, antisocial behaviour, and dependence. Many studies have implicated genetic variability in the genes encoding monoamine oxidase A (MAOA) and the serotonin transporter (5HTT) in modulating susceptibility to these conditions. Paradoxically, the risk variants of these genes have been shown, in vitro, to increase levels of serotonin, although many of the conditions are associated with decreased levels of serotonin. Furthermore, in adult humans, and monkeys with orthologous genetic polymorphisms, there is no observable correlation between these functional genetic variants and the amount or activity of the corresponding proteins in the brain. These seemingly contradictory data might be explained if the association between serotonin and these behavioural and psychiatric conditions were mainly a consequence of events taking place during foetal and neonatal brain development. In this review we explore, based on recent research, the hypothesis that the dual role of serotonin as a neurotransmitter and a neurotrophic factor has a significant impact on behaviour and risk for neuropsychiatric disorders through altered development of limbic neurocircuitry involved in emotional processing, and development of the serotonergic neurons, during early brain development

The Intersection of Interfacial Forces and Electrochemical Reactions

We review recent developments in experimental techniques that simultaneously combine measurements of the interaction forces or energies between two extended surfaces immersed in electrolyte solutions—primarily aqueous—with simultaneous monitoring of their (electro)chemical reactions and controlling the electrochemical surface potential of at least one of the surfaces. Combination of these complementary techniques allows for simultaneous real time monitoring of angstrom level changes in surface thickness and roughness, surface–surface interaction energies, and charge and mass transferred via electrochemical reactions, dissolution, and adsorption, and/or charging of electric double layers. These techniques employ the surface forces apparatus (SFA) combined with various “electrochemical attachments” for in situ measurements of various physical and (electro)chemical properties (e.g., cyclic voltammetry), optical imaging, and electric potentials and currents generated naturally during an interaction, as well as when electric fields (potential differences) are applied between the surfaces and/or solution—in some cases allowing for the chemical reaction equation to be unambiguously determined. We discuss how the physical interactions between two different surfaces when brought close to each other (<10 nm) can affect their chemistry, and suggest further extensions of these techniques to biological systems and simultaneous in situ spectroscopic measurements for chemical analysis

Burial induced changes in physical sandstone properties: A case-study of North Sea and Norwegian Sea sandstone formations

The changes in physical properties of sandstones with burial depth are a result of mechanical and chemical compaction processes. These processes are affected by rock microstructure, pressure regimes and temperature history. Data from 30 wells have been used to investigate and compare the changes in porosity, bulk density, elastic moduli and wave propagation velocities between mid- Jurassic sandstones in the North Sea and the Norwegian Sea. Mechanical compaction and quartz cementation models are used together with rock physics diagnostics to describe these changes

Quantitative Modeling in the North Sea: Towards a More Confident Assessment of the Critical Risks

Quantitative modeling has become a standard part of probability assessment, for both hydrocarbon systems analysis and reservoir quality prediction, undertaken in association with prospectivity evaluation in the Norwegian North Sea and Haltenbanken areas. Presently, the Norwegian North Sea and parts of Haltenbanken can be classified as mature basins. As such, quantitative assessment is focussed towards assessment of prospects lying on basin margins outside known kitchen areas; satellite prospect assessment in and around existing infrastructure; and assessment of deep, often high-pressure, high-temperature (HP/HT) prospects in basin centers. Outside the known kitchen areas, access to a long-distance petroleum migration route is critical for success. In the proximity of existing infrastructure petroleum migration and trapped fluid gas-to-oil ratio (GOR) are often key risks. In deep, HP/HT settings reservoir quality and top-seal integrity are often the most important factors. Application of quantitative models in these environments allows a consistent evaluation methodology, testing of the consequences of geological uncertainty, and an improvement in confidence. We will illustrate the use of 3D migration modeling to assess migration fairways close to existing infrastructure and outside known kitchens; our experience of matching observed fluid GOR using 2D compositional modeling; and how we model porosity evolution in HP/HT areas and the influence that thermally controlled quartz diagenesis has on overpressure build-up and top-seal leakage. These examples show how quantitative modeling tools and new understanding of fundamental processes are being used and developed today in the North Sea and Halten bank