555 research outputs found
Do individual differences in emotion regulation mediate the relationship between mental toughness and symptoms of depression?
Mental Toughness (MT) provides crucial psychological capacities for achievement in sports, education, and work settings. Previous research examined the role of MT in the domain of mental health and showed that MT is negatively associated with and predictive of fewer depressive symptoms in nonclinical populations. The present study aimed at (1) investigating to what extent mentally tough individuals use two emotion regulation strategies: cognitive reappraisal and expressive suppression; (2) exploring whether individual differences in emotion regulation strategy use mediate the relationship between MT and depressive symptoms. Three hundred sixty-four participants (M = 24.31 years, SD = 9.16) provided self-reports of their levels of MT, depressive symptoms, and their habitual use of cognitive reappraisal and expressive suppression. The results showed a statistically significant correlation between MT and two commonly used measures of depressive symptoms. A small statistically significant positive correlation between MT and the habitual use of cognitive reappraisal was also observed. The correlation between MT and the habitual use of expressive suppression was statistically significant, but the size of the effect was small. A statistical mediation model indicated that individual differences in the habitual use of expressive suppression mediate the relationship between MT and depressive symptoms. No such effect was found for the habitual use of cognitive reappraisal. Implications of these findings and possible avenues for future research are discussed
Hindsight policy gradients
A reinforcement learning agent that needs to pursue different goals across
episodes requires a goal-conditional policy. In addition to their potential to
generalize desirable behavior to unseen goals, such policies may also enable
higher-level planning based on subgoals. In sparse-reward environments, the
capacity to exploit information about the degree to which an arbitrary goal has
been achieved while another goal was intended appears crucial to enable sample
efficient learning. However, reinforcement learning agents have only recently
been endowed with such capacity for hindsight. In this paper, we demonstrate
how hindsight can be introduced to policy gradient methods, generalizing this
idea to a broad class of successful algorithms. Our experiments on a diverse
selection of sparse-reward environments show that hindsight leads to a
remarkable increase in sample efficiency.Comment: Accepted to ICLR 201
Reinforcement Learning in Sparse-Reward Environments with Hindsight Policy Gradients
A reinforcement learning agent that needs to pursue different goals across episodes requires a goal-conditional policy. In addition to their potential to generalize desirable behavior to unseen goals, such policies may also enable higher-level planning based on subgoals. In sparse-reward environments, the capacity to exploit information about the degree to which an arbitrary goal has been achieved while another goal was intended appears crucial to enabling sample efficient learning. However, reinforcement learning agents have only recently been endowed with such capacity for hindsight. In this letter, we demonstrate how hindsight can be introduced to policy gradient methods, generalizing this idea to a broad class of successful algorithms. Our experiments on a diverse selection of sparse-reward environments show that hindsight leads to a remarkable increase in sample efficiency
Wear Properties of A Shock Consolidated Metallic Glass and Glass-Crystalline Mixtures
Powder flakes prepared from 50 μm thick melt spun ribbons of Markomet 1064 (Ni_(52.5)Mo_(38)Cr_8 B_(1.5) wt%) were shock consolidatedin the unannealed and annealed condition. The unannealed flakes (microhardness 933 kg/mm^2) are amorphous while flakes annealed at 900ºC for 2 hours have an fcc structure with a grain size of 0.3 μm and microhardness of 800 kg/mm^2. The shock consolidated amorphous powder compact (250 kJ/kg shock energy) shows no crystal peaks in an X-ray diffractometer scan. Compacts of annealed powder (400 to 600 kJ/kg shock energies) contain amorphous material (18-21%) which was rapidly quenched from the melt formed at interparticle regions during the consolidation process. The microhardness of the amorphous interparticle material is 1100 kg/mm^2. Wear properties of the compacts measured in low velocity pin on disk tests show low average dynamic friction values (∿0.03). The 60 hour cumulative wear appears to correlate with the energy of shock compaction and surface porosity of the compacts rather than the metallic glass content
Understanding online political networks: The case of the far-right and far-left in Greece
This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.This paper examines the connectivity among political networks on Twitter. We explore dynamics inside and between the far right and the far left, as well as the relation between the structure of the network and sentiment. The 2015 Greek political context offers a unique opportunity to investigate political communication in times of political intensity and crisis. We explore interactions inside and between political networks on Twitter in the run up to the elections of three different ballots: the parliamentary election of 25 January, the bailout referendum of 5 July, the snap election of 20 September; we, then, compare political action during campaigns with that during routinized politics.This work received funding from the European Union Horizon 2020 Programme (Horizon2020/2014–2020), under grant agreement 688380
Dynamic transformation of small Ni particles during methanation of CO under fluctuating reaction conditions monitored by X-ray absorption spectroscopy
A 10 wt.-% Ni/AlO catalyst with Ni particles of about 4 nm was prepared and applied in the methanation of CO under dynamic reaction conditions. Fast phase transformations between metallic Ni, NiO and NiCO were observed under changing reaction atmospheres using operando X-ray absorption spectroscopy (XAS). Removing H from the feed gas and, thus, simulating a H dropout during the methanation reaction led to oxidation of the active sites. The initial reduced state of the Ni particles could not be recovered under methanation atmosphere (H/CO = 4); this was only possible with an effective reactivation step applying H at increased temperatures. Furthermore, the cycling of the gas atmospheres resulted in a steady deactivation of the catalyst. Operando XAS is a powerful tool to monitor these changes and the behavior of the catalyst under working conditions to improve the understanding of the catalytic processes and deactivation phenomena
Cohort Profile: The Study of Cognition, Adolescents and Mobile Phones (SCAMP)
The Study of Cognition, Adolescents and Mobile Phones (SCAMP) is a prospective secondary school-based cohort study established to investigate whether use of mobile phones and other wireless devices that emit radio-frequency electromagnetic fields (RF-EMF) is associated with cognitive, behavioural, educational, physical and mental health outcomes during adolescence. Specifically, the principal aim is to discern whether any observed associations may be due to: (i) RF-EMF exposure from mobile phones; (ii) a combination of various RF-EMF sources (e.g. digital enhanced cordless technology phones or wireless internet); or (iii) other behavioural reasons associated with technology use for communication and entertainment, irrespective of exposure to RF-EMF
Numerical observation of non-axisymmetric vesicles in fluid membranes
By means of Surface Evolver (Exp. Math,1,141 1992), a software package of
brute-force energy minimization over a triangulated surface developed by the
geometry center of University of Minnesota, we have numerically searched the
non-axisymmetric shapes under the Helfrich spontaneous curvature (SC) energy
model. We show for the first time there are abundant mechanically stable
non-axisymmetric vesicles in SC model, including regular ones with intrinsic
geometric symmetry and complex irregular ones. We report in this paper several
interesting shapes including a corniculate shape with six corns, a
quadri-concave shape, a shape resembling sickle cells, and a shape resembling
acanthocytes. As far as we know, these shapes have not been theoretically
obtained by any curvature model before. In addition, the role of the
spontaneous curvature in the formation of irregular crenated vesicles has been
studied. The results shows a positive spontaneous curvature may be a necessary
condition to keep an irregular crenated shape being mechanically stable.Comment: RevTex, 14 pages. A hard copy of 8 figures is available on reques
Night-time screen-based media device use and adolescents’ sleep and health-related quality of life.
Objective: The present study investigates the relationship between night-time screen-based media devices (SBMD) use, which refers to use within one hour before sleep, in both light and dark rooms, and sleep outcomes and health-related quality of life (HRQoL) among 11 to 12-year-olds.
Methods: We analysed baselined data from a large cohort of 6,616 adolescents from schools in and around London, United Kingdom, participating in the Study of Cognition Adolescents and Mobile Phone (SCAMP). Adolescents self-reported their use of any SBMD (mobile phone, tablet, laptop, television etc.). Sleep variables were derived from self-reported weekday and/or weekend bedtime, sleep onset latency (SOL) and wake time. Sleep quality was assessed using four standardised dimensions from the Swiss Health Survey. HRQoL was estimated using the KIDSCREEN-10 questionnaire.
Results
Over two-thirds (71.5%) of adolescents reported using at least one SBMD at night-time, and about a third (32.2%) reported using mobile phones at night-time in darkness. Night-time mobile phone and television use was associated with higher odds of insufficient sleep duration on weekdays (Odds Ratio, OR= 1.82, 95% Confidence Interval, CI [1.59, 2.07] and OR=1.40, 95% CI [1.23, 1.60], respectively). Adolescents who used mobile phones in a room with light were more likely to have insufficient sleep (OR=1.32, 95% CI [1.10, 1.60]) and later sleep midpoint (OR=1.64, 95% CI [1.37, 1.95]) on weekends compared to non-users. The magnitude of these associations was even stronger for those who used mobile phones in darkness for insufficient sleep duration on weekdays (OR=2.13, 95% CI [1.79, 2.54]) and for later sleep midpoint on weekdays (OR=3.88, 95% CI [3.25, 4.62]) compared to non-users. Night-time use of mobile phones in light was not associated with HRQoL but use in darkness was associated with a lower KIDSCREEN-10 score (β= -1.19, 95% CI [-1.83, -0.56]) compared to no use.
Conclusions: We found consistent associations between night-time SBMD use and poor sleep outcomes and worse HRQoL in adolescents. The magnitude of these associations was stronger when SBMD use occurred in a dark room versus a lit room
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