scholarly journals A simple explanation for the “shuffling phenomenon” for lozenge tilings of dented hexagons

2021 ◽  
Vol 344 (7) ◽  
pp. 112396
Author(s):  
Markus Fulmek
Keyword(s):  
Simple Explanation ◽  
Lozenge Tilings

CONCEPT-BASED LEARNING DAN KEMAMPUAN BERFIKIR KRITIS MATEMATIS

2020 ◽  
Vol 2 (1) ◽  
Author(s):  
Maifalinda Fatra ◽  
A Rizki ◽  
Tita Khalis Maryati
Keyword(s):  
Critical Thinking ◽  
Mathematics Learning ◽  
Sampling Technique ◽  
Thinking Skills ◽  
Learning Model ◽  
Critical Thinking Skills ◽  
Control Group ◽  
Simple Explanation ◽  
Critical Thinking Ability ◽  
Thinking Ability

Mathematical Critical thinking is one of  mathematical abilities that must be obtained by students. Critical thinking is one of the high order thinking processes that can make concepts in student knowledge.  Students with critical thinking in mathematics learning mostly do rational activities such as interpreting information based on a particular theoretical framework, linking theory with practice, making claims and justifying it, utilizing data in support of argumentation, making relations or relationships between various ideas, asking questions, evaluating knowledge, predict, describe something, analyze, synthesize, and categorize. This study aims to analyze the effect of the Concept-Based Learning Model on the critical thingking mathematical abilities.The purpose of this research is to analyze the effect of Concept-Based Learning Model toward mathematics critical thinking ability. The method used in this research is quasi experiment by Randomize Control Group Post Test Only Design with cluster random sampling technique. Indicators of mathematics critical thinking skills measured in this study include providing simple explanations, building basic skills, concluding, making more explanations, and deciding an action. The results showed that the mathematics critical thinking ability of students in the experimental class for the five indicators that being analyze was higher than the ability of students in the control class. A fairly high difference in the indicator showed in give a simple explanation and concluding. and it means that the application of Concept-Based Learning Model significantly influences the  abilities  of students' mathematics critical thinking.

Behavioural and EEG atypicalities during rest, visual perception, and cognitive control in autistic adults

2020 ◽  
Author(s):  
Amandine Lassalle ◽  
Michael X Cohen ◽  
Laura Dekkers ◽  
Elizabeth Milne ◽  
Rasa Gulbinaite ◽  
...  
Keyword(s):  
Visual Perception ◽  
Cognitive Control ◽  
Visual Processing ◽  
Autism Spectrum ◽  
Neural Dynamics ◽  
Simple Explanation ◽  
Control Task ◽  
Neural Structure ◽  
Eeg Power ◽  
Autistic Adults

Background: People with an Autism Spectrum Condition diagnosis (ASD) are hypothesized to show atypical neural dynamics, reflecting differences in neural structure and function. However, previous results regarding neural dynamics in autistic individuals have not converged on a single pattern of differences. It is possible that the differences are cognitive-set-specific, and we therefore measured EEG in autistic individuals and matched controls during three different cognitive states: resting, visual perception, and cognitive control.Methods: Young adults with and without an ASD (N=17 in each group) matched on age (range 20 to 30 years), sex, and estimated Intelligence Quotient (IQ) were recruited. We measured their behavior and their EEG during rest, a task requiring low-level visual perception of gratings of varying spatial frequency, and the “Simon task” to elicit activity in the executive control network. We computed EEG power and Inter-Site Phase Clustering (ISPC; a measure of connectivity) in various frequency bands.Results: During rest, there were no ASD vs. controls differences in EEG power, suggesting typical oscillation power at baseline. During visual processing, without pre-baseline normalization, we found decreased broadband EEG power in ASD vs. controls, but this was not the case during the cognitive control task. Furthermore, the behavioral results of the cognitive control task suggest that autistic adults were better able to ignore irrelevant stimuli.Conclusions: Together, our results defy a simple explanation of overall differences between ASD and controls, and instead suggest a more nuanced pattern of altered neural dynamics that depend on which neural networks are engaged.

Anion effect on alkali ion-crown complex formation in a moderately concentrated solutions: A sensitive probe of hidden interionic interactions operating in dissociating protic solvents

1990 ◽  
Vol 55 (5) ◽  
pp. 1149-1161
Author(s):  
Jiří Závada ◽  
Václav Pechanec ◽  
Oldřich Kocián
Keyword(s):  
Hydrogen Bond ◽  
Complex Formation ◽  
Charge Density ◽  
Macrocyclic Ligand ◽  
Simple Explanation ◽  
Anion Effect ◽  
Protic Solvents ◽  
The Individual ◽  
Alkali Salts ◽  
Alkali Ion

A powerful anion effect destabilizing alkali ion-crown complex formation has been found to operate in moderately concentrated protic (H2O, CH3OH, C2H5OH) solution, following the order HO- > AcO- > Cl- > Br- > NO3- > I- > NCS-. Evidence is provided that the observed effect does not originate from ion-pairing. A simple explanation is provided in terms of concordant hydrogen bond bridges of exalted stability between the gegenions, M+···OR-H···(OR-H)n···OR-H···A-. It is proposed that encapsulation of alkali ion by the macrocyclic ligand leads to a dissipation of the cation charge density destroying its ability to participate in the hydrogen bond bridge. An opposition against the alkali ion-crown complex formation arises accordingly in the solution in dependence on strength of the hydrogen bridge; for a given cation, the hydrogen bond strength increases with increasing anion charge density from NCS- to HO-(RO-). It is pointed out, at the same time, that the observed anion effect does not correlate with the known values of activity coefficients of the individual alkali salts which are almost insensitive to anion variation under the investigated conditions. As a resolution of the apparent paradoxon it is proposed that, in absence of the macrocyclic ligand, the stabilizing (concordant) bonding between the gegenions is nearly balanced by a destabilizing (discordant) hydrogen bonding between the ions of same charge (co-ions). Intrinsic differences among the individual salts are thus submerged in protic solvents and become apparent only when the concordant bonding is suppressed in the alkali ion-crown complex formation.

scholarly journals Human perceptual learning is delayed by the N-methyl-D-aspartate receptor partial agonist D-cycloserine

2021 ◽  
pp. 026988112098634
Author(s):  
Harriet Dempsey-Jones ◽  
Susann Steudte-Schmiedgen ◽  
Michael Browning ◽  
Tamar R Makin ◽  
Marcella L Woud ◽  
...  
Keyword(s):  
Perceptual Learning ◽  
Psychological Treatment ◽  
Longitudinal Design ◽  
Partial Agonist ◽  
Tactile Perception ◽  
Simple Explanation ◽  
Tactile Learning ◽  
Before And After ◽  
Learning And Cognition ◽  
To Receive

Background: The optimisation of learning has long been a focus of scientific research, particularly in relation to improving psychological treatment and recovery of brain function. Previously, partial N-methyl-D-aspartate agonists have been shown to augment reward learning, procedural learning and psychological therapy, but many studies also report no impact of these compounds on the same processes. Aims: Here we investigate whether administration of an N-methyl-D-aspartate partial agonist (D-cycloserine) modulates a previously unexplored process – tactile perceptual learning. Further, we use a longitudinal design to investigate whether N-methyl-D-aspartate-related learning effects vary with time, thereby providing a potentially simple explanation for apparent mixed effects in previous research. Methods: Thirty-four volunteers were randomised to receive one dose of 250 mg D-cycloserine or placebo 2 h before tactile sensitivity training. Tactile perception was measured using psychophysical methods before and after training, and 24/48 h later. Results: The placebo group showed immediate within-day tactile perception gains, but no further improvements between-days. In contrast, tactile perception remained at baseline on day one in the D-cycloserine group (no within-day learning), but showed significant overnight gains on day two. Both groups were equivalent in tactile perception by the final testing – indicating N-methyl-D-aspartate effects changed the timing, but not the overall amount of tactile learning. Conclusions: In sum, we provide first evidence for modulation of perceptual learning by administration of a partial N-methyl-D-aspartate agonist. Resolving how the effects of such compounds become apparent over time will assist the optimisation of testing schedules, and may help resolve discrepancies across the learning and cognition domains.

scholarly journals A New View on Young Pulsars in Supernova Remnants: Slow, Radio-quiet & X-ray Bright

2000 ◽  
Vol 177 ◽  
pp. 699-702 ◽  
Author(s):  
E. V. Gotthelf ◽  
G. Vasisht
Keyword(s):  
Magnetic Field ◽  
Neutron Stars ◽  
Supernova Remnants ◽  
Simple Explanation ◽  
Crab Pulsar ◽  
Radio Pulsars ◽  
Substantial Fraction ◽  
Subsequent Evolution ◽  
X Ray ◽  
Field Decay

AbstractWe propose a simple explanation for the apparent dearth of radio pulsars associated with young supernova remnants (SNRs). Recent X-ray observations of young remnants have revealed slowly rotating (P∼ 10s) central pulsars with pulsed emission above 2 keV, lacking in detectable radio emission. Some of these objects apparently have enormous magnetic fields, evolving in a manner distinct from the Crab pulsar. We argue that these X-ray pulsars can account for a substantial fraction of the long sought after neutron stars in SNRs and that Crab-like pulsars are perhaps the rarer, but more highly visible example of these stellar embers. Magnetic field decay likely accounts for their high X-ray luminosity, which cannot be explained as rotational energy loss, as for the Crab-like pulsars. We suggest that the natal magnetic field strength of these objects control their subsequent evolution. There are currently almost a dozen slow X-ray pulsars associated with young SNRs. Remarkably, these objects, taken together, represent at least half of the confirmed pulsars in supernova remnants. This being the case, these pulsars must be the progenitors of a vast population of previously unrecognized neutron stars.

Modelling Electromigration and Induced Stresses In Aluminum Lines

1993 ◽  
Vol 309 ◽  
Author(s):  
R. Kirchheim
Keyword(s):  
Beneficial Effect ◽  
General Equation ◽  
Concentration Profiles ◽  
Simple Explanation ◽  
Vacancy Model ◽  
Induced Stresses

AbstractThe various equations used by different authors for describing electromigration are compiled. All of them can be derived from a general equation which is based on a vacancy model. During the derivation of simplified versions of the general equations assumptions have to be made and their effect on concentration profiles and/or electromigration stresses developing as a function of time are discussed. Consequences with respect to Blech's experiment or the current exponent in Black's equation are taken into consideration and a simple explanation is provided for the beneficial effect of a (111) texture on the reliability of Al-lines.

scholarly journals A mass-flux perspective of the tidewater glacier cycle

2016 ◽  
Vol 62 (231) ◽  
pp. 82-93 ◽  
Author(s):  
JASON M. AMUNDSON
Keyword(s):  
Deep Water ◽  
Mass Flux ◽  
Large Scale ◽  
Stable Configuration ◽  
Simple Explanation ◽  
Surface Mass ◽  
Tidewater Glaciers ◽  
Tidewater Glacier ◽  
Variable Sensitivity ◽  
Negative Feedbacks

AbstractI explore the tidewater glacier cycle with a 1-D, depth- and width-integrated flow model that includes a mass-flux calving parameterization. The parameterization is developed from mass continuity arguments and relates the calving rate to the terminus velocity and the terminus balance velocity. The model demonstrates variable sensitivity to climate. From an advanced, stable configuration, a small warming of the climate triggers a rapid retreat that causes large-scale drawdown and is enhanced by positive glacier-dynamic feedbacks. Eventually, the terminus retreats out of deep water and the terminus velocity decreases, resulting in reduced drawdown and the potential for restabilization. Terminus readvance can be initiated by cooling the climate. Terminus advance into deep water is difficult to sustain, however, due to negative feedbacks between glacier dynamics and surface mass balance. Despite uncertainty in the precise form of the parameterization, the model provides a simple explanation of the tidewater glacier cycle and can be used to evaluate the response of tidewater glaciers to climate variability. It also highlights the importance of improving parameterizations of calving rates and of incorporating sediment dynamics into tidewater glacier models.

Sign in / Sign up

Export Citation Format

Share Document