24 research outputs found

    Dust evolution in protoplanetary disks

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    We investigate the behaviour of dust in protoplanetary disks under the action of gas drag using our 3D, two-fluid (gas+dust) SPH code. We present the evolution of the dust spatial distribution in global simulations of planetless disks as well as of disks containing an already formed planet. The resulting dust structures vary strongly with particle size and planetary gaps are much sharper than in the gas phase, making them easier to detect with ALMA than anticipated. We also find that there is a range of masses where a planet can open a gap in the dust layer whereas it doesn't in the gas disk. Our dust distributions are fed to the radiative transfer code MCFOST to compute synthetic images, in order to derive constraints on the settling and growth of dust grains in observed disks.Comment: 6 pages, 5 figures, to appear in the Proceedings of IAU Symp. 249: Exoplanets: Detection, Formation and Dynamics (Suzhou, China

    Characterization of a cinnamoyl-CoA reductase 1 (CCR1) mutant in maize: effects on lignification, fibre development, and global gene expression

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    Cinnamoyl-CoA reductase (CCR), which catalyses the first committed step of the lignin-specific branch of monolignol biosynthesis, has been extensively characterized in dicot species, but few data are available in monocots. By screening a Mu insertional mutant collection in maize, a mutant in the CCR1 gene was isolated named Zmccr1–. In this mutant, CCR1 gene expression is reduced to 31% of the residual wild-type level. Zmccr1– exhibited enhanced digestibility without compromising plant growth and development. Lignin analysis revealed a slight decrease in lignin content and significant changes in lignin structure. p-Hydroxyphenyl units were strongly decreased and the syringyl/guaiacyl ratio was slightly increased. At the cellular level, alterations in lignin deposition were mainly observed in the walls of the sclerenchymatic fibre cells surrounding the vascular bundles. These cell walls showed little to no staining with phloroglucinol. These histochemical changes were accompanied by an increase in sclerenchyma surface area and an alteration in cell shape. In keeping with this cell type-specific phenotype, transcriptomics performed at an early stage of plant development revealed the down-regulation of genes specifically associated with fibre wall formation. To the present authors’ knowledge, this is the first functional characterization of CCR1 in a grass species

    Self-defining memories in recently detoxified alcohol-dependent patients

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    Patients with alcohol dependence have been shown to be impaired in recalling specific autobiographical events, yet little is known on how changes in the memory of these events may impact their self-representation. In this study, we examined Self-Defining Memories (SDMs), a specific type of autobiographical memory that plays a key role in the construction of personal identity, in 25 patients with alcohol dependence, abstinent from alcohol from 10 days to 6 months, compared to 28 control subjects. We observed that SDMs in patients were significantly less specific and included more reference to alcohol than those of controls. Patients also reported more SDMs with negative emotional valence and higher emotional intensity. These results suggest that recently abstinent alcohol-dependent patients may be prone to define themselves by negative events referring to alcohol consumption, which may contribute to an unfavorable perception of their self and subsequently of their ability to remain abstinent. These findings should be taken into account to optimize psychological approaches in the treatment of alcohol-dependence. © 2016 Elsevier Ireland Lt

    Contributing roles of depression, anxiety, and impulsivity dimensions in eating behaviors styles in surgery candidates

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    International audienceAbstract Background Even if bariatric surgery is considered the most effective therapeutic approach, it is not equally successful among individuals suffering from severe obesity and candidates for this weight loss surgery. Among the factors that influence postsurgical outcomes, eating behaviors styles are known to play a key role in relapses. The aim of our study was to assess eating behaviors styles and several modulating psychopathological factors in patients suffering from severe obesity. Methods Patients seeking bariatric surgery (N = 127) completed a set of standardized tools assessing eating behaviors (Dutch Eating Behavior Questionnaire), comorbid psychiatric conditions (Mini International Neuropsychiatric Interview), depression, and anxiety scores (Beck Depression Inventory, State-Trait Anxiety Inventory), and impulsivity scores (UPPS-P Impulsive Behavior Scale). Results We detected significant correlations between DEBQ Emotional Eating (EmoE) and depression, state and trait anxiety, and all dimensions of impulsivity. Significant correlations were also present between DEBQ External Eating (ExtE) and depression, state and trait anxiety and UPPS-P positive urgency, lack of perseverance and sensation seeking. Regression analyses identified sex (female), trait anxiety, and lack of perseverance as explanatory factors for EmoE, and depression severity score and positive urgency for ExtE. Conclusions EmoE might be a means of dealing with negative emotions and/or intrusive thoughts, while ExtE might result from a mechanism associated with depression. These results should help to improve patients’ outcomes by defining specific therapeutic targets in psychological interventions. Plain English summary After bariatric surgery, some patients regain weight. This is likely due to various factors, including a return of maladaptive eating styles, such as emotional eating (which occurs as a response to negative emotions, like depression, anxiety, anger, sadness, and discouragement), external eating (which refers to the tendency to eat in response to positive external cues, regardless of internal signals of hunger and satiety), and restraint eating (implying to make efforts to develop and maintain strategies to control calories intake, associated with weight loss after lifestyle intervention). Our goal in this research project was to explore associated factors (particularly depression, anxiety, and impulsivity) to these eating styles in patients suffering from obesity prior to bariatric surgery. Individuals seeking bariatric surgery were asked questions about their eating styles and their levels of depression, anxiety, and impulsivity using standardized questionnaires. We found that emotional eating might be a means of dealing with negative emotions and/or intrusive thoughts (e.g. about food or body dissatisfaction), while external eating might result from a mechanism associated with depression. We detected no association between restraint eating and any of the dimensions of impulsivity, nor depression and anxiety. Therapies aimed at improving patients’ abilities to regulate negative affects seem promising among subjects suffering from obesity and those seeking bariatric surgery. If well learned, these therapies might also help them to maintain weight loss after surgery by limiting maladaptive eating styles

    Growing dust grains in protoplanetary discs – III. Vertical settling

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    We aim to derive a simple analytic model to understand the essential properties of vertically settling growing dust grains in laminar protoplanetary discs. Separating the vertical dynamics from the motion in the disc midplane, we integrate the equations of motion for both a linear and an exponential grain growth rate. Numerical integrations are performed for more complex growth models. We find that the settling efficiency depends on the value of the dimensionless parameter gamma, which characterises the relative efficiency of grain growth with respect to the gas drag. Since gamma is expected to be of order as the initial dust-to-gas ratio in the disc (of order 10^-2), grain growth enhances the energy dissipation of the dust particles and improve the settling efficiency in protoplanetary discs. This behaviour is mostly independent of the growth model considered as well as of the radial drift of the particles.Comment: 8 pages, 9 figures. Accepted for publication in MNRAS. v2: typos corrected and minor change

    Geothermal Resources Development - HGP-A Wellhead Generator Proof of Feasibility Project

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    Project: A 3 MW plant with single flash steam system. Totally enclosed plant building integrated with a visitors' center, within a fully developed site. Location: Puna District, Island of Hawaii. Construction Cost: US $8,000,000. Completed: Schedule completion August 1980. (This plant was officially dedicated, July 17, 1981 and is currently delivering energy to HELCO Power System in Hawaii. HELCO is operating this plant for the University of Hawaii). Services: Concept studies, preliminary design, final design, procurement and construction management

    Neural Responses to the Implicit Processing of Emotional Facial Expressions in Binge Drinking.

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    Emotional processing is a crucial ability in human and impairments in the processing of emotions are considered as transdiagnostic processes in psychopathology. In alcohol use disorder, numerous studies have investigated emotional processing and showed emotional deficits related to the perpetuation of alcohol use. Recent studies have also explored this topic in binge drinking, but few studies are available. In this paper, we explored whether emotional difficulties in binge drinking may be extended to implicit emotion processing. We compared 39 binge drinkers (BD) and 40 non-binge drinkers who performed a gender categorization task while faces represented emotional expressions of anger, fear, happiness and sadness. Emotional brain responses were assessed thanks to functional magnetic resonance imaging. Emotional versus non-emotional conditions were first contrasted in the whole sample and groups were then compared. Emotional condition led to differential activations than non-emotional condition, supporting the validity of the paradigm. Regarding group comparisons, BD exhibited higher activations in the left posterior cerebellum (anger processing) and the right anterior cingulate (fear processing) as well as lower activations in the left insula (happiness), the right post-central gyrus, the right cingulate gyrus and the right medial frontal gyrus (sadness processing). Beyond emotional identification, BD presented differential brain responses following the implicit processing of emotions. Emotional difficulties in binge drinking might be related to a more automatic/unconscious processing of emotions
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