Extraordinary plastic behaviour of the γ′ precipitate in a directionally solidified nickel-based superalloy

The deformation behaviour of the γ′ precipitate in a directionally solidified nickel-based superalloy is investigated using microscopic observations after tensile testing at room temperature. It is found that coarse γ′ precipitates (604 nm) are sheared by strongly coupled dislocations, and some γ′ precipitates are elongated to approximately 3–6 times of their original lengths. It reveals that, at room temperature, the γ′ precipitate within the experimental superalloy has a significant plastic deformation capacity in comparison with Ni₃Al bulk alloys. Based on the experimental observations, the extraordinary plastic behaviour of the γ′ precipitate is analysed.     

Study of γ/γ′ interfacial width in a nickel-based superalloy by scanning transmission electron microscopy

The γ/γ′ interfaces are thought to play an important role in determining the mechanical properties in single-crystal nickel-based superalloys. In this article, interfacial width in DD6, one second-generation single-crystal superalloy containing 2 wt% Re, has been studied by means of scanning transmission electron microscopy. From an atomic resolution high angle annular dark field image, both compositional interfaces and order–disorder interfaces are studied, and it is first found that the interfacial width of chemical composition is same with that between the ordered and disordered phases.     

Interactions between interfacial dislocations and γ/γ′ interface during high temperature – low stress creep in nickel-based single crystal superalloy

ABSTRACT

The interaction between interfacial dislocations and γ/γ′ interface is critical to the high temperature creep properties of single crystal superalloys. However, only a few studies have paid attention to the detailed structure such as local interfacial morphologies and the elemental distribution around interfacial dislocations. In this paper, the interfacial protrusions and related dislocations in a single crystal superalloy after creep at high temperature – low stress have been investigated in detail. It is found that the morphology and size of the interfacial protrusions remain almost the same during the early and middle stages of high temperature creep, which indicates a local equilibrium at the interfacial protrusions. Steps at different height are formed at the γ/γ′ interface at the initial stage of high temperature creep since dislocations could move along the γ/γ′ interface, which indicates that dislocation motion at different creep stage may affect the morphology of γ/γ′ interface.     

Core structure of a〈100〉 superdislocations in a single-crystal superalloy during high-temperature and low-stress creep

A thorough TEM analysis has been carried out to study the dislocations cutting into γ′ phase in a single-crystal superalloy during uniaxial tensile creep under high-temperature and low-stress conditions. It is proved that the a〈100〉 edge superdislocation originates from the interfacial a〈100〉 dislocations and moves into the γ′ phase by pure climbing. And the dissociation of the a〈100〉 superdislocation core into two a/2〈101〉 superpartial dislocations during uniaxial tensile creep has been identified by HRTEM method for the first time.     

Preschoolers’ oculomotor behaviour during their observation of an action task

Adult and child oculomotor behaviour was measured during the observation of a naturalistic action task. Adult and 4-year-old participants viewed a video presentation of an actor making a root-beer float. Eye movements were monitored to examine fixation patterns during a series of means–end action sequences. Look-ahead fixations (i.e., gaze anticipation) were measured to determine if children would saccade to the goal site prior to the completion of each action sequence as adults do. Look-ahead fixations were observed in both the adult and child groups, with no significant age differences found in levels of gaze anticipation.     

Effect of motorcycle lighting configurations on drivers’ perceptions of closing during nighttime driving

ObjectiveThe aims were to better understand how drivers perceive an approaching set of motorcycle headlights during nighttime driving and to determine whether alternative motorcycle headlight configurations improve drivers’ perceptual judgments of closing for an oncoming motorcycle.BackgroundMotorcyclists account for a disproportionate number of roadway fatalities, especially at night. One potential cause of this is drivers’ misjudgments of a motorcycle’s approach.MethodThe first experiment examined whether drivers were more sensitive to horizontal or vertical optical expansion and whether drivers could integrate these two dimensions to achieve a lower looming threshold. A second experiment built on these results to test whether alternative headlight configurations that maximized size were better than other motorcycle headlight configurations and a car’s headlights. In both experiments, participants were instructed to press a button to indicate when they first perceived an oncoming vehicle to be closing under nighttime driving conditions.ResultsHeadlight orientation did not affect when drivers perceived closing, and drivers were not able to integrate optical expansion from multiple dimensions in a way that achieves a lower looming threshold. However, the alternative motorcycle headlight configurations that accentuated the full extent of a motorcycle’s size resulted in drivers perceiving closing sooner than other motorcycle headlight configurations but not sooner than a car.ConclusionDrivers perceive closing sooner for larger headlight configurations except when the headlight configurations are relatively small, in which case the effect of headlight size is attenuated.ApplicationDrivers’ perceptual judgments of motorcycles may improve when motorcycles have headlights that span its full height.     

Therapists’ Subjective Experience during Improvisational Moments in the Clinical Encounter-Discussion of I’mprovisation

With this discussion, I reflect on the limitations of this pilot qualitative research. These include how categories of observation are established and the generalizability of the reported results beyond the small sample of subjects studied. Additionally, the metaphor of theater used by the investigators for understanding improvisation is compared and contrasted with the metaphor of jazz improvisation. Jazz improvisation as a metaphor works well with the quantitative data coming from infant/caregiver video studies. These studies represent a more micro focus on embodied registrations of the emotional/behavioral interactive process and account for data which might be otherwise unconsciously overlooked or dissociated with a strategy valorizing I’mprovisation. I then visit the question of whether improvisation should be held as an ideal versus an ideal of continuous practice and vigilance for how theoretical biases, personal credos and habits of activity can become unreflective traps blocking spontaneous emergent possibilities for clinically relevant movement and growth.     

Development of students’ knowledge about didactics during their first year of the master’s programme in didactics

In this study, I reflect critically on my own experiences as a university teacher of students’ expressed knowledge about the academic subject of didactics at the beginning and end of their first semester as students in the Master’s Programme in Didactics. My reflections are made using a phenomenographic approach to learning, which regards learning as a qualitatively deeper and different way of understanding content. The results of the study are expected to deepen my understanding of knowledge expressed about didactics in two different student groups, and give insight on what is critical for knowledge development in higher education. The first course design consisted of 12 lectures in total by 12 different teachers representing different fields of didactics, such as general didactics and subject-based didactics in different specializations. The second course design consisted of eight seminars where course literature about didactics was discussed, together with three seminars in smaller groups wherein the students in each specialization of didactics met. A comparison between the groups is made, based on a qualitative analysis of the responses on an open question before and after the first semester forms the basis of my own reflections. The analysis aims to establish in what way the students’ explanations of didactics might have changed during the courses, and if there are differences in this development which could be explained by differences in course design. In the first student group, 10 students (in-service teachers) answered both questionnaires, and 11 students in the second group answered both questionnaires.     

Mediation of Mothers’ Anxiety and Parenting in Children’s Behavior Problems during COVID-19

The outbreak of COVID-19 is affecting the lives of millions of families around the world. The current study was carried out in Israel, following the pandemic’s initial outbreak and during the resulting enforced quarantine, confining parents and children to their homes. A sample of 141 Israeli mothers with at least one child between the ages of 3 and 12 (M?=?6.92, SD?=?2.55) participated as volunteers. About half the sample (50.7%) consisted of girls. Most mothers were cohabiting with a spouse (93%). Mothers completed online questionnaires about their perceptions about the health and economic threats of COVID-19, availability of social support, their anxiety symptoms, hostile/coercive and supportive/engaged parenting behavior, and their children’s behavior problems. Results showed expected significant associations between the mothers’ reports about having little social support, their anxiety symptoms, hostile/coercive and supportive/engaged parenting behavior, and children’s externalizing problems. Likewise, expected significant associations were found between mothers’ perceptions about the health and economic threats of COVID-19, their anxiety symptoms, hostile/coercive parenting behavior, and children’s internalizing and externalizing problems. Importantly, maternal anxiety and hostile/coercive parenting behavior mediated the associations between lack of support, negative perceptions about the health and economic threats of COVID-19, and children’s behavior problems. These findings stress the importance of mothers’ mental health and parenting behaviors for children’s socioemotional adaptation in the context of COVID-19. Implications of the findings for family interventions intended to help parents and children at this time are suggested.

     

Predictors of undergraduate students’ university support service use during the first year of university

University support services can be a beneficial resource for students coping with personal stressors. This study investigated the predictors of service use by undergraduate students during their first year at university. Participants completed self-report measures of problem-solving effectiveness, psychological distress and perceived social support (availability and satisfaction) at the start of the academic year, frequency of exposure to stressors half-way through the first semester and support service use at the end of the first and second semesters. Perceived availability of social support and frequency of exposure to stressors predicted service use. Additional analyses examined change in psychological distress across the first semester. Implications of these findings are discussed.     

The influence of practicum supervisors’ facilitation styles on student teachers’ reflective thinking during collective reflection

Student teachers’ reflective thinking is closely associated with learning and improving practice. Novice student teachers require adequate support to reflect more deeply. The role of ‘others’ in collective reflection and knowledge generation as an outcome creates a platform for deep reflection, addressing both the processes and premises of reflective thinking. Facilitation styles of practicum supervisors could influence the level of student teachers’ reflective thinking during collective reflection. This is a case study using purposeful sampling involving a Malaysian teacher training institution that conducted an undergraduate early childhood programme in collaboration with a UK university. Sources of evidence were interviews, direct observations and documents. Data collected were analysed using both inductive and deductive methods. It was found that facilitation styles influence the depth of student teachers’ reflective thinking during group dialogic reflection. A continuum of facilitation styles from collaborative to instructive typologies was constructed. The implications of these findings are discussed.     

Parental evaluation of teachers’ competences and characteristics during COVID-19 pandemic homeschooling

Social Psychology of Education - With the spread of the SARS-CoV-2 virus, school-related closures and the hasty transition into homeschooling, parents were required to take a more active and...     

First-time mothers’ experiences of meaningfulness during their third trimester of pregnancy: A focus on spirituality

This study sought to gain in-depth understanding of the lived experiences of first-time mothers during their third trimester of pregnancy. The non-probability, purposive sample were Afrikaans speaking first-time mothers aged between 22 and 40 years. Data on their experiences of meaningfulness during their pregnancy were collected using the Mmogo-Method® and reflective journals. The data were thematically analyzed combining textual data and visual depictions. This group of first-time mothers expressed a very personal relationship with a Divine reality that they rely on and derive meaningfulness from their pregnancy and birthing experiences. They perceived a Divine reality as the giver of life and that they were given a responsibility to carry new life. Sense of meaningfulness during pregnancy was strongly associated with spirituality.     

The influence of a reading task on children’s eye movements during reading

In the present study, second graders (n= 23), fourth graders (n= 16), sixth graders (n= 24) and adults (n= 21) read texts adopted from children’s science textbooks either with the task to answer a “why” question presented as the title of the text or for comprehension when their eye movements were recorded. Immediately after reading, readers answered a text memory and an integration question. Second graders showed an effect of questions as increased processing during first-pass reading, whereas older readers showed the effect in later look-backs. For adult readers, questions also facilitated first-pass reading. Text memory or integration question-answering was not influenced by the reading task. The results indicate that questions increase the standards of coherence for text information and that already young readers do modify their reading behaviour according to task demands.     

Parental Mediation of COVID-19 News and Children’s Emotion Regulation during Lockdown

Journal of Child and Family Studies - The COVID-19 outbreak resulted in a large amount of emotionally charged messaging that is believed to have a tremendous psychological impact, particularly on...     

Discussion of “I’mprovisation–Therapists’ Subjective Experience during Improvisational Moments in the Clinical Encounter”

The first part of this article discusses Romanelli, Tishby, and Moran’s qualitative research on the impact of training clinicians’ “skill-sets” derived from improvisational theater. Categories of experience were discerned from the data, along with findings of the impressive positive effects from the training on the clinicians’ ability to better respond to unpredictable “improvisational moments” in psychotherapy. The second part elaborates on how the authors' research represents a welcome addition to a larger conversation about how drama theory “puts” “flesh and blood” on the “bones” of Relational Metapsychology, which entails theories of process and change, rooted in an information theory based epistemology in contrast to Freud’s archaic and deeply flawed Metapsychology ensconced in a psychic energy theory epistemology. Finally, the authors’ lends to advocacy for clinical training in drama and improvisation being added to clinically based curriculums.     

Maternal Behavior Modifications during Pretense and Their Long-Term Effects on Toddlers’ Understanding of Pretense

Recent studies indicate the need to investigate the sources of toddlers’ understanding of another person's pretense. The present study is a cultural and longitudinal extension of the work of Lillard and Witherington (2004 Lillard, A. S. & Witherington, D. C. (2004). Mothers’ behavior modifications during pretense and their possible signal value for toddlers. Developmental Psychology, 40, 95–113. doi:10.1037/0012-1649.40.1.95[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]), who claimed that mothers modify their behaviors during pretense and that the some of these behavior modifications help their toddlers understand maternal pretense. Experiment 1 investigated whether mothers would change their behaviors during pretense with a sample of 31 Japanese mother–infant pairs. Experiment 2, with a subsample of 20 mother–child pairs who had participated in Experiment 1, examined whether the maternal behavior modifications at 18 months predicted their toddlers’ understanding of pretense at 24 months. The results of Experiment 1 indicated that Japanese mothers smiled more frequently, gazed at their toddlers longer, used sound effects more frequently, and engaged in more frequent snack-related actions in a “pretense condition” than in a “real condition.” In addition, some of these behaviors were significantly related to their toddlers’ apparent understanding of pretense. Experiment 2 showed that both the frequency of maternal smiles and the number of sound effects in the pretense condition at 18 months predicted toddlers’ understanding of the pretense enacted by a strange adult at 24 months. This research indicates the impact of maternal behavior modifications during pretense on the development of symbolic thought in the 2nd year of life.     

Evaluation of an integrated lighting-warning system on motorists’ yielding at unsignalized crosswalks during nighttime

Drivers’ yielding behavior to pedestrians during nighttime was assessed in seven different conditions of crosswalk lighting: (a) baseline condition with standard road lighting; (b) enhanced LED lighting that increased lighting level from 70 to 120 lx; (c) flashing orange beacons on top of the backlit pedestrian crossing sign; (d) in-curb LED strips on the curbsides of the zebra crossing with steady light emission; (e) in-curb LED strips with flashing light emission; (d) all previous devices activated with in-curb LED strips in steady mode; (e) all previous devices activated with in-curb LED strips in flashing mode. For every condition 100 trials were recorded with a staged pedestrian that initiated a standardized crossing when a vehicle was approaching. The frequency of drivers’ yielding was computed for each condition. A significant increase for yielding compliance was recorded from standard road lighting to enhanced dedicated lighting (19–38.21%), and from enhanced dedicated lighting to the seventh condition with the flashing beacons and the flashing in-curb LED strips activated (38.21–63.56%). The results showed that the integrated lighting-warning system for pedestrian crossings was effective in increasing motorists’ yielding to pedestrians during nighttime.     

Utility of center of pressure measures during obstacle crossing in prediction of fall risk in people with Parkinson’s disease

IntroductionPostural instability during walking and tripping over obstacles are the main causes of falls in people with Parkinson’s disease (PD). Preliminary limited evidence suggests that the length of the prospective follow-up period affects falls prediction in PD, with shorter periods leading to more accurate prediction. Thus, the primary aim of the present study was to test the performance of center of pressure (CoP) variables during obstacle crossing to predict fall risk in people with PD during subsequent periods of four, six, and 12 months. We also compared CoP variables during obstacle crossing between fallers and non-fallers.MethodsForty-two individuals with PD, in mild to moderate stages, completed the baseline obstacle crossing assessment and reported falls for 12 months. Participants walked at their self-selected pace and were instructed to cross an obstacle (half knee height) positioned in the middle of an 8-m long pathway. A force platform was used to analyze CoP parameters of the stance phase of the trailing limb (most affected limb). The ability of each outcome measure to predict fall risk at four, six, and 12 months was assessed using receiver operating characteristic curve analyses.ResultsTen individuals (23.8%) were considered fallers at four months, twelve individuals (28.5%) at six months, and twenty-one individuals (50%) at 12 months. CoP amplitude and CoP velocity in the mediolateral direction significantly predicted fall risk at four, six, and 12 months. As judged by the area under the curve, mediolateral CoP velocity showed the best performance at four months, while mediolateral CoP amplitude showed the best performance at six months. Fallers presented greater values of mediolateral CoP velocity and amplitude than non-fallers.ConclusionThese findings suggest that mediolateral CoP velocity and amplitude during obstacle crossing might be useful to predict fall risk in people with PD. Therefore, larger studies are encouraged.