Is seeing believing? Linking fixation bias and flexibility with interpretation flexibility

Many people are afraid of spiders and consider them to be both dangerous and disgusting, which can negatively impact their mental well-being as well as their relationship with nature. Very few studies have examined what characteristics draw visual attention toward or away from spiders, or have assessed the impact of arachnophobia and sex on attentional biases. Here, 118 undergraduate students freely viewed single and paired images of spiders and other arthropods in their natural environments while having their eye movements monitored. Participants also completed a survey measuring spider phobia and attitudes toward spiders. Multiple eyetracking metrics (total dwell time, first run dwell time, first fixation time, and run count) were used as indicators of attentional bias. Findings suggest a general avoidance of spider images in the presence of other non-spider arthropod images as well as avoidance of scorpion images in the presence of non-scorpion arachnid images. Presentation of image pairs with two kinds of spiders elicit attention toward spider-specific features. These effects were occasionally, though not often, moderated by sex and phobia levels. Across all metrics, there was a tendency to record longer first fixation times, shorter dwell times, and lesser run counts toward images of spiders. Images of jumping spiders and insects received considerably more and faster attentional allocation relative to other spiders. Understanding how general body form versus specific spider features influence visual attention provides insight into visual factors that may motivate spider phobia, providing evidence-based knowledge that could be useful in treatments. Additionally, knowledge of potentially appealing features of spiders may provide useful perspectives for communicating the usefulness of spiders in our ecosystem.

There is an urgent need to advance understanding of the neural underpinnings of depression, especially early in the life span. Examination of neural dynamics using resting-state functional magnetic resonance imaging (fMRI) data can provide indices of neural flexibility, which may provide important new insights for the neurobiology of pediatric depression. Here we applied Hidden Markov Modeling (HMM) to resting-state fMRI data to investigate neural flexibility in relation to depression and suicidal thinking in children. We utilized data from the Adolescent Brain Cognitive Development℠ Study (ABCD Study), and included data from 10,763 children (9-10 years) who completed two 5-min resting state fMRI scans at the baseline visit. After applying the NeuroMark framework to the data, HMM was applied with a varying number of states; a six-state model was selected from candidate models based on between-scan reliability. We applied linear mixed-effect modeling to test the relationship between two clinical predictors: current major depressive disorder (MDD) diagnosis and presence of suicidal ideation (SI) with our primary outcome for neural flexibility: the frequency of transitions between HMM-derived states ("state-switching"), while including sex, age, and other socio-demographic variables as covariates. Analyses were conducted both with and without correction for head motion. We also explored relationships with total time and dwell time in each state of the six states. Lower state-switching during rest was associated with both MDD and SI, although these findings were no longer significant after correcting for head motion. Notably, state-switching was inversely related to head motion and was higher in females than males. Exploratory analysis showed that MDD was associated with shorter dwell time in one state and longer dwell time in another, suggesting altered temporal persistence of specific neural configurations. Tentative evidence supported our hypothesis that lower state-switching in children with MDD and SI may reflect a reduction in brain flexibility, potentially contributing to a tendency to become "stuck" in negative patterns of thinking and feeling. However, the relatively low frequency of these problems in late childhood reduced statistical power after correcting for motion. Future research is needed to assess these relationships at later adolescent time points, when higher prevalence of depression and SI and lower prevalence of head motion will allow more powerful tests of these associations.

Introduction Educators need real time evidence of how students process pre class quiz items in flipped courses, not just whether answers are right or wrong. We examined whether two classroom feasible eye tracking metrics—fixation intensity (total dwell time) and regression rate (proportion of backward saccades)—provide interpretable, item level signals of cognitive engagement once surface text features are taken into account. Methods Thirty four undergraduates completed 320 analysable attempts on 55 multiple choice items coded by Bloom’s taxonomy while a 60 Hz tracker recorded gaze. Crossed mixed effects models included a covariate for each item’s total word count. A logistic mixed model tested whether fixation intensity and regression rate predicted correctness beyond Bloom level, gender, and length. After each block, students reported perceived mental effort to compare subjective and gaze based indicators. Results After controlling for total word count, Bloom category did not uniquely predict fixation intensity or regression rate, suggesting that previously observed demand patterns largely reflected text length. In the accuracy model, fixation intensity showed a small, positive association with being correct, whereas regression rate showed a small, negative association. Discussion In authentic flipped class quizzes, fixation intensity and regression rate can serve as complementary, real time indicators of engagement, but only when item length and layout are standardised or statistically modelled. Claims about differences across Bloom levels should be made cautiously. We outline design guidance for future item banks—length matched stems, fixed numbers of options, and pre registered word count covariates—to enable firmer inferences and practical classroom diagnostics.

A linear source table to determine the treatment times for cylindrical applicators used in high–dose rate brachytherapy

The paper is concerned with the physical and metallurgical changes that occur in hot forging dies. These changes are examined by the execution of simple upsetting tests on a Petro-Forge high speed hammer. Each test involves the forging of 1000 steel (En 8) billets using flat dies in two materials, No.5 and H.50 steels. The temperature conditions for each test are varied by changes in the dwell time, from 5 ms to 1 s, and by the use of either unlubricated dies or dies lubricated with a colloidal graphite-water mix. Macroscopic examinations of the surfaces, and microscopic examinations and microhardness tests of surface sections are carried out on each pair of dies. It is found that dwell time affects the condition of the die surfaces in two distinct areas, for both die materials. In the die centre, with lubricated dies, a mild form of cracking present at the shortest dwell time, disappears as the dwell time increases. In contrast, away from the die centre, where metal flow and die surface temperatures are likely to be at a maximum, severe cracking is present at the longest dwell time and this reduces to a minimum as the dwell time is reduced. There was little evidence of cracking in any area with unlubricated dies. The micro-examinations reveal the presence of a layer of martensite away from the die centre with lubricated dies, the layer thickness increasing with dwell time. It is also thicker with No.5 than with H.50 dies. No transformation is evident at the die centre, nor when unlubricated dies are used. It is argued that during hot forging there are four possible temperature-cycles per blow with respect to the minimum and maximum surface temperatures in relation to the austenite and martensite transformation temperatures, and in only one case is martensite found in the die surface. This case corresponds to the conditions reported, when a water-based lubricant is applied and when the dwell time is sufficiently long for austenite to be formed. The effects of the dwell time and of a change in die material prove this supposition. The effects of temperature cycling and phase transformations on the thermal fatigue of the dies is discussed. It is concluded that transformation is the major cause of the severe cracking created in certain die areas of the reported results. It is stated that the use of coolants, as opposed to lubricants, in hot forging is a compromise and can be detrimental except where long dwell or contact times lead to severe softening of the working surfaces of the dies.

Scant data exist on normal bolus dwell time assessed during flexible endoscopic evaluation of swallowing (FEES). The purpose of this study was to examine bolus dwell time in healthy older adults. Because it has been previously reported that some healthy older adults aspirate, we also sought to determine if bolus dwell time varied as a function of aspiration status. Prospective. Seventy-six healthy volunteers from the seventh, eighth, and ninth decades of life participated. Dwell times were analyzed via FEES as a function of pharyngeal location, liquid type, delivery method, purée type, viscosity, age, and gender. Longer dwell times were evidenced with the eldest participants, straw delivery, and the smallest volume. Adults in the ninth decade were 4.8 (P = .01) and 3.8 (P = .02) times more likely to have longer dwell times at the vallecula and 7.1 (P = .002) and 3.8 (P = 0.02) at the pyriform sinus than those in the seventh and eighth decades, respectively. Longer dwell times at the vallecula and pyriform sinuses were 2 and 2.38 times (P < .0001) more likely for straw than cup delivery, respectively. Boluses of 5 mL were 1.5 times (P < .05) more likely to result in longer dwell times than larger volumes. Bolus dwell times did not significantly differ as a function of aspiration status. Advanced age, straw delivery, and small volumes yielded longer dwell times. These variables should be considered before diagnosing an abnormal bolus dwell time in elder patients.

Many studies on eutectic solder by Amagai in 1999, Sharma and Dasgupta in 2003 and Zhai, Sidharth and Blish in 2003 have shown that the dwell time beyond certain limit has a minimal effect on the MTTF. Additional dwell time will not produce additional damage beyond a limit or boundary. However, our experiments consistently showed that the fatigue life of the lead-free solder balls decreases significantly when the dwell time increases from 15 minutes, to 30 minutes and until 90 minutes. Further failure analysis confirms that the failure mode and failure location is same when dwell time changes. The longer dwell time is, the more accumulated creep damage is. The results imply that it takes long time to entirely achieve the relaxation for the lead-free solder material. In addition, results also showed that the lead-free solder joint during thermal shock fails faster than thermal cycling. The faster ramp rate does impose more damage on solder joint than a slow ramp rate. It is concluded that the ramp time and dwell time have conflicting effects on solder joint reliability. Finite element analysis is conducted to have a fundamental understanding of the effects of ramp rate and dwell time on lead-free alloys. A remarkable agreement on the correlation between the finite element analysis and experimental results was achieved. The numerical results revealed the failure mechanism of solder joint associated with the ramp rate and dwell time. Thermal shock has a much faster ramp rate, thus imposing much more damage to the solder joints than thermal cycling. In that sense, the fatigue life decreased when the frequency increased. However, a longer dwell time causes more creep in the solder joint, thereby lowering the fatigue life significantly. This means that fatigue life decreases when frequency decreases. It can be concluded that frequency as a single parameter for a reliability model doesn't account for the conflicting effects of ramp rate and dwell time. The finite element results also show that the majority of damage occurs during the ramp period. The dwell time at high temperature is predicted to have a negligible contribution to the total inelastic strain energy density

Recent studies have found that longer dwell times, or the period of time between deployments, may be protective against combat-related psychological outcomes. The purpose of this study was to examine the association between dwell time and psychological morbidity, while accounting for combat exposure. U.S. Marines with two combat deployments between 2005 and 2008 were identified from electronic deployment records. Those who screened positive for post-traumatic stress disorder and depression, and who were referred for mental health services were identified from the Post-Deployment Health Assessment. For the final study sample of 3,512 Marines, dwell time was calculated as time between deployments, and was analyzed as a ratio over length of first deployment. After adjustment for all covariates, there was an interaction (p = 0.01) between dwell time and combat exposure on mental health referral outcome. For personnel with maximum reported combat exposure, longer dwell times were associated with a 49% to 92% reduced odds of mental health referral. Longer dwell times may be protective against combat-related psychological outcomes. Because multiple deployments are likely to be the norm in future military operations, regulating dwell time, particularly for those with greater risk of combat exposure, should continue to be explored.

Accurate prediction and management of train dwell times are essential for achieving efficient and sustainable public transport operations. This study evaluates established statistical dwell-time models within the context of Victoria’s regional railway network, contrasting their predictions with empirical data from video-based observations. Historically, these models—rooted in linear and non-linear regression analyses—have been designed for urban settings in peak periods. However, their applicability to regional railways, characterised by lower service frequencies with unique infrastructure and operational constraints, has been underexplored. The models were assessed for their ability to predict both passenger flow time and total dwell time under regional operating conditions. Results show that while passenger flow time can be predicted with moderate accuracy (best model R2 ≈ 0.65), total dwell time models perform considerably worse (best model R2 ≈ 0.25), largely due to unmodelled operational delays. The analysis identifies door operation cycles and conductor procedures as the primary operational variables influencing variability in total dwell time. Additionally, variations in passenger behaviour between peak and off-peak periods affect model performance. The findings underscore the need to incorporate local operational and behavioural factors into dwell-time models to enhance their predictive reliability for regional rail contexts. This study provides an empirical foundation for refining dwell time modelling approaches, supporting policymakers and operators in improving scheduling efficiency and overall service sustainability in regional rail networks.

Neurotypical observers show large and reliable individual differences in gaze behavior along several semantic object dimensions. Individual gaze behavior toward faces has been linked to face identity processing, including that of neurotypical observers. Here, we investigated potential gaze biases in Super-Recognizers (SRs), individuals with exceptional face identity processing skills. Ten SRs, identified with a novel conservative diagnostic framework, and 43 controls freely viewed 700 complex scenes depicting more than 5000 objects. First, we tested whether SRs and controls differ in fixation biases along four semantic dimensions: faces, text, objects being touched, and bodies. Second, we tested potential group differences in fixation biases toward eyes and mouths. Finally, we tested whether SRs fixate closer to the theoretical optimal fixation point for face identification. SRs showed a stronger gaze bias toward faces and away from text and touched objects, starting from the first fixation onward. Further, SRs spent a significantly smaller proportion of first fixations and dwell time toward faces on mouths but did not differ in dwell time or first fixations devoted to eyes. Face fixation of SRs also fell significantly closer to the theoretical optimal fixation point for identification, just below the eyes. Our findings suggest that reliable superiority for face identity processing is accompanied by early fixation biases toward faces and preferred saccadic landing positions close to the theoretical optimum for face identification. We discuss future directions to investigate the functional basis of individual fixation behavior and face identity processing ability.

Introduction: Visual search is a task that humans perform in everyday life. Whether it involves looking for a pen on a desk or a mass in a mammogram, the cognitive and perceptual processes that underpin these tasks are identical. Radiologists are experts in visual search of medical images and studies on their visual search behaviours have revealed some interesting findings with regard to diagnostic errors. In Australia, within the modality of ultrasound, sonographers perform the diagnostic scan, select images and present to the radiologist for reporting. Therefore the visual task and potential for errors is similar to a radiologist. Our aim was to explore and understand the detection, localisation and eye‐gaze behaviours of a group of qualified sonographers. Method: We measured clinical performance and analysed diagnostic errors by presenting fifty sonographic breast images that varied on cancer present and degree of difficulty to a group of sonographers in their clinical workplace. For a sub‐set of sonographers we obtained eye‐tracking metrics such as time‐to‐first fixation, total visit duration and cumulative dwell time heat maps. Results: The results indicate that the sonographers' clinical performance was high and the eye‐tracking metrics showed diagnostic error types similar to those found in studies on radiologist visual search. Conclusion: This study informs us about sonographer visual search patterns and highlights possible ways to improve diagnostic performance via targeted education.

Predictors and outcomes of lead extraction requiring a bailout femoral approach: Data from 2 high-volume centers

Prevalence and Characterization of Interaction of Retrievable Inferior Vena Cava Filters with the Spine in Patients Undergoing Complex Filter Removal

Fractured Bard Recovery, G2, and G2 Express Inferior Vena Cava Filters: Incidence, Clinical Consequences, and Outcomes of Removal Attempts

Effects of dwell time during sintering on electrical properties of 0.98(K0.5Na0.5)NbO3–0.02LaFeO3 ceramics