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Metallurgical defects in metal laser additive manufacturing (LAM) are inevitable due to complex non-equilibrium thermodynamics. A laser ultrasonic system was designed for detecting surface/near-surface defects in the layer-by-layer LAM process. An approach was proposed for ultrasonic imaging of defects based on variable time window intensity mapping with adaptive 2σ threshold denoising. The Gaussian mixture model hypothesis and expectation-maximization algorithm can automatically differentiate between components dominated by defects and background noises, thereby providing an adaptive threshold that accommodates detection environments and surface roughness levels. Results show that the ultrasonic wave reflection at defect boundaries diminishes far-field ultrasonic intensity upon pulsed laser irradiation on surface defects, enabling defect size and location characterization. This method is applicable to LAM samples with a significant surface roughness of up to 37.5 µm. It can detect superficial and near-surface defects down to 0.5 mm in diameter and depth, making it significant for online defect detection in additive manufacturing.

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Our aims were: (1) to characterize gay, bisexual and other men who have sex with men (GBMSM) and transgender (TG) populations using internet-based self-sampling services in the TESTATE project or attending community-based STI/HIV voluntary counselling and testing (CBVCT) services as alternative strategies to formal HIV testing within the Spanish national health system, and (2) to identify factors associated with repeat use of the same screening strategy from November 2018 to December 2021. Demographic, health, and behavioral characteristics of users using complementary strategies were analyzed. We developed a cross-sectional study, with descriptive analysis, HIV cascade, and a multivariate logistic model to identify factors associated with participants' repeated use of the same screening strategy. We included 9939 users, of whom 94.1% were GBMSM (n = 9348) and 5.9% TG (n = 580), with a high representation of migrants. Reactive results were 3.4% (n = 340), with 3.0% in GBMSM (n = 277/9348) and 10.7% in TG (n = 63/591). 73.8% (n = 251) were confirmed HIV positive and 76.7% (n = 194) were linked to health services. Users repeated the online screening strategy more than CBVCT (44.3% vs. 31.8%), but TG population used face-to-face community services more (8.4% vs. 0.6%). Factors influencing the repetition of the online self-sampling strategy included older age, non-migrant status, and recent HIV testing. In the CBVCT strategy, factors included older age, TG identity, non-migrant status, condom use during the last sexual encounter, and recent HIV testing. In conclusion, both CBVCT and online-requested self-sampling at home are important alternatives to the health system for the provision of HIV testing to GBMSM and TG.

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Infecciones por VIH , Prueba de VIH , Homosexualidad Masculina , Minorías Sexuales y de Género , Personas Transgénero , Humanos , Masculino , España/epidemiología , Adulto , Estudios Transversales , Infecciones por VIH/diagnóstico , Infecciones por VIH/prevención & control , Infecciones por VIH/epidemiología , Prueba de VIH/métodos , Prueba de VIH/estadística & datos numéricos , Homosexualidad Masculina/estadística & datos numéricos , Homosexualidad Masculina/psicología , Personas Transgénero/estadística & datos numéricos , Personas Transgénero/psicología , Minorías Sexuales y de Género/estadística & datos numéricos , Minorías Sexuales y de Género/psicología , Persona de Mediana Edad , Internet , Adulto Joven , Tamizaje Masivo/métodos , Autoevaluación , Adolescente , Bisexualidad/estadística & datos numéricos , Conducta Sexual

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To solve the high error phenomenon of microelectromechanical systems (MEMS) due to their poor signal-to-noise ratio, this paper proposes an online compensation algorithm wavelet threshold back-propagation neural network (WT-BPNN), based on a neural network and designed to effectively suppress the random error of MEMS arrays. The algorithm denoises MEMS and compensates for the error using a back propagation neural network (BPNN). To verify the feasibility of the proposed algorithm, we deployed it in a ZYNQ-based MEMS array hardware. The experimental results showed that the zero-bias instability, angular random wander, and angular velocity random wander of the gyroscope were improved by about 12 dB, 10 dB, and 7 dB, respectively, compared with the original device in static scenarios, and the dispersion of the output data was reduced by about 8 dB in various dynamic environments, which effectively verified the robustness and feasibility of the algorithm.

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INTRODUCTION: A major limitation in Alzheimer's disease (AD) research is the lack of the ability to measure cognitive performance at scale-robustly, remotely, and frequently. Currently, there are no established online digital platforms validated against plasma biomarkers of AD. METHODS: We used a novel web-based platform that assessed different cognitive functions in AD patients (N = 46) and elderly controls (N = 53) who were also evaluated for plasma biomarkers (amyloid beta 42/40 ratio, phosphorylated tau ([p-tau]181, glial fibrillary acidic protein, neurofilament light chain). Their cognitive performance was compared to a second, larger group of elderly controls (N = 352). RESULTS: Patients with AD were significantly impaired across all digital cognitive tests, with performance correlating with plasma biomarker levels, particularly p-tau181. The combination of p-tau181 and the single best-performing digital test achieved high accuracy in group classification. DISCUSSION: These findings show how online testing can now be deployed in patients with AD to measure cognitive function effectively and related to blood biomarkers of the disease. Highlights: This is the first study comparing online digital testing to plasma biomarkers.Alzheimer's disease patients and two independent cohorts of elderly controls were assessed.Cognitive performance correlated with plasma biomarkers, particularly phosphorylated tau (p-tau)181.Glial fibrillary acidic protein and neurofilament light chain, and less so the amyloid beta 42/40 ratio, were also associated with performance.The best cognitive metric performed at par to p-tau181 in group classification.

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Human social life requires an understanding of the mental states of one's social partners. Two people who look at the same objects often experience them differently, as a twinkling light or a planet, a 6 or a 9, and a random cat or Cleo, their pet. Indeed, a primary purpose of communication is to share distinctive experiences of objects or events. Here, we test whether toddlers (14-15 months) are sensitive to another agent's distinctive experiences of pictures when determining the goal underlying the agent's actions in a minimally social context. We conducted nine experiments. Across seven of these experiments (n = 206), toddlers viewed either videotaped or live events in which an actor, whose perspective differed from their own, reached (i) for pictures of human faces that were upright or inverted or (ii) for pictures that depicted a rabbit or a duck at different orientations. Then either the actor or the toddler moved to a new location that aligned their perspectives, and the actor alternately reached to each of the two pictures. By comparing toddlers' looking to the latter reaches, we tested whether their goal attributions accorded with the actor's experience of the pictured objects, with their own experience of the pictured objects, or with no consistency. In no experiment did toddlers encode the actor's goal in accord with his experiences of the pictures. In contrast, in a similar experiment that manipulated the visibility of a picture rather than the experience that it elicited, toddlers (n = 32) correctly expected the actor's action to depend on what was visible and occluded to him, rather than to themselves. In a verbal version of the tasks, older children (n = 35) correctly inferred the actor's goal in both cases. These findings provide further evidence for a dissociation between two kinds of mental state reasoning: When toddlers view an actor's object-directed action under minimally social conditions, they take account of the actor's visual access to the object but not the actor's distinctive experience of the object.

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Atención , Solución de Problemas , Humanos , Masculino , Animales , Conejos , Niño , Adolescente , Orientación

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BACKGROUND: In Ontario, Canada we developed and implemented an online screening algorithm for the distribution of HIV self-tests, known as GetaKit. During the COVID pandemic, we adapted the GetaKit algorithm to screen for COVID based on population and infection data and distributed COVID rt-LAMP self-tests (using the Lucira Check-It®) to eligible participants. METHODS: GetaKit/COVID was a prospective observational study that occurred over a 7-month period from September 2021 to April 2022. All potential participants completed an online registration and risk assessment, including demographic information, COVID symptoms and risk factors, and vaccination status. Bivariate comparisons were performed for three outcomes: results reporting status, vaccination status, and COVID diagnosis status. Data were analysed using Chi-Square for categorial covariates and Independent Samples T-Test and Mann-Whitney U test for continuous covariates. Bivariate logistic regression models were applied to examine associations between the covariates and outcomes. RESULTS: During the study period, we distributed 6469 COVID self-tests to 4160 eligible participants; 46% identified as Black, Indigenous or a Person of Colour (BIPOC). Nearly 70% of participants reported their COVID self-test results; 304 of which were positive. Overall, 91% also reported being vaccinated against COVID. Statistical analysis found living with five or fewer people, having tested for COVID previously, and being fully vaccinated were positive factors in results reporting. For COVID vaccination, people from large urban centers, who identified their ethnicity as white, and who reported previous COVID testing were more likely to be fully vaccinated. Finally, being identified as a contact of someone who had tested positive for COVID and the presence of COVID-related symptoms were found to be positive factors in diagnosis. CONCLUSIONS: While most participants who accessed this service were vaccinated against COVID and the majority of diagnoses were identified in participants who had symptoms of, or an exposure to, COVID, our program was able to appropriately link participants to recommended follow-up based on reported risks and results. These findings highlight the utility of online screening algorithms to provide health services, particularly for persons with historical barriers to healthcare access, such as BIPOC or lower-income groups.

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COVID-19 , Humanos , COVID-19/diagnóstico , COVID-19/epidemiología , COVID-19/prevención & control , Ontario/epidemiología , Prueba de COVID-19 , Tamizaje Masivo/métodos , Vacunación

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Does knowledge of other people's minds grow from concrete experience to abstract concepts? Cognitive scientists have hypothesized that infants' first-person experience, acting on their own goals, leads them to understand others' actions and goals. Indeed, classic developmental research suggests that before infants reach for objects, they do not see others' reaches as goal-directed. In five experiments (N = 117), we test an alternative hypothesis: Young infants view reaching as undertaken for a purpose but are open-minded about the specific goals that reaching actions are aimed to achieve. We first show that 3-month-old infants, who cannot reach for objects, lack the expectation that observed acts of reaching will be directed to objects rather than to places. Infants at the same age learned rapidly, however, that a specific agent's reaching action was directed either to an object or to a place, after seeing the agent reach for the same object regardless of where it was, or to the same place regardless of what was there. In a further experiment, 3-month-old infants did not demonstrate such inferences when they observed an actor engaging in passive movements. Thus, before infants have learned to reach and manipulate objects themselves, they infer that reaching actions are goal-directed, and they are open to learning that the goal of an action is either an object or a place. RESEARCH HIGHLIGHTS: In the present experiments, 3-month-old prereaching infants learned to attribute either object goals or place goals to other people's reaching actions. Prereaching infants view agents' actions as goal-directed, but do not expect these acts to be directed to specific objects, rather than to specific places. Prereaching infants are open-minded about the specific goal states that reaching actions aim to achieve.

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Objetivos , Motivación , Lactante , Humanos , Aprendizaje , Formación de Concepto , Conocimiento

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Online methods allow testing of larger, more diverse populations, with much less effort than in-lab testing. However, many psychophysical measurements, including visual crowding, require accurate eye fixation, which is classically achieved by testing only experienced observers who have learned to fixate reliably, or by using a gaze tracker to restrict testing to moments when fixation is accurate. Alas, both approaches are impractical online as online observers tend to be inexperienced, and online gaze tracking, using the built-in webcam, has a low precision (±4 deg). EasyEyes open-source software reliably measures peripheral thresholds online with accurate fixation achieved in a novel way, without gaze tracking. It tells observers to use the cursor to track a moving crosshair. At a random time during successful tracking, a brief target is presented in the periphery. The observer responds by identifying the target. To evaluate EasyEyes fixation accuracy and thresholds, we tested 12 naive observers in three ways in a counterbalanced order: first, in the laboratory, using gaze-contingent stimulus presentation; second, in the laboratory, using EasyEyes while independently monitoring gaze using EyeLink 1000; third, online at home, using EasyEyes. We find that crowding thresholds are consistent and individual differences are conserved. The small root mean square (RMS) fixation error (0.6 deg) during target presentation eliminates the need for gaze tracking. Thus, this method enables fixation-dependent measurements online, for easy testing of larger and more diverse populations.

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The auditory system is unique among sensory systems in its ability to phase lock to and precisely follow very fast cycle-by-cycle fluctuations in the phase of sound-driven cochlear vibrations. Yet, the perceptual role of this temporal fine structure (TFS) code is debated. This fundamental gap is attributable to our inability to experimentally manipulate TFS cues without altering other perceptually relevant cues. Here, we circumnavigated this limitation by leveraging individual differences across 200 participants to systematically compare variations in TFS sensitivity to performance in a range of speech perception tasks. Results suggest that robust TFS sensitivity does not confer additional masking release from pitch or spatial cues, but appears to confer resilience against the effects of reverberation. Yet, across conditions, we also found that greater TFS sensitivity is associated with faster response times, consistent with reduced listening effort. These findings highlight the perceptual significance of TFS coding for everyday hearing.

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A growing literature is demonstrating a link between working memory (WM) and speech-in-noise (SiN) perception. However, the nature of this correlation and which components of WM might underlie it, are being debated. We investigated how SiN reception links with auditory sensory memory (aSM) - the low-level processes that support the short-term maintenance of temporally unfolding sounds. A large sample of old (N = 199, 60-79 yo) and young (N = 149, 20-35 yo) participants was recruited online and performed a coordinate response measure-based speech-in-babble task that taps listeners' ability to track a speech target in background noise. We used two tasks to investigate implicit and explicit aSM. Both were based on tone patterns overlapping in processing time scales with speech (presentation rate of tones 20 Hz; of patterns 2 Hz). We hypothesised that a link between SiN and aSM may be particularly apparent in older listeners due to age-related reduction in both SiN reception and aSM. We confirmed impaired SiN reception in the older cohort and demonstrated reduced aSM performance in those listeners. However, SiN and aSM did not share variability. Across the two age groups, SiN performance was predicted by a binaural processing test and age. The results suggest that previously observed links between WM and SiN may relate to the executive components and other cognitive demands of the used tasks. This finding helps to constrain the search for the perceptual and cognitive factors that explain individual variability in SiN performance.

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Percepción del Habla , Habla , Humanos , Anciano , Habla/fisiología , Audición/fisiología , Ruido/efectos adversos , Percepción del Habla/fisiología , Memoria a Corto Plazo/fisiología

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This paper aims to compare a new webcam-based eye-tracking system, integrated into the Labvanced platform for online experiments, to a "gold standard" lab-based eye tracker (EyeLink 1000 - SR Research). Specifically, we simultaneously recorded data with both eye trackers in five different tasks, analyzing their real-time performance. These tasks were a subset of a standardized test battery for eye trackers, including a Large Grid task, Smooth Pursuit eye movements, viewing natural images, and two Head Movements tasks (roll, yaw). The results show that the webcam-based system achieved an overall accuracy of 1.4°, and a precision of 1.1° (standard deviation (SD) across subjects), an error of about 0.5° larger than the EyeLink system. Interestingly, both accuracy (1.3°) and precision (0.9°) were slightly better for centrally presented targets, the region of interest in many psychophysical experiments. Remarkably, the correlation of raw gaze samples between the EyeLink and webcam-based was at about 90% for the Large Grid task and about 80% for Free View and Smooth Pursuit. Overall, these results put the performance of the webcam-based system roughly on par with mobile eye-tracking devices (Ehinger et al. PeerJ, 7, e7086, 2019; Tonsen et al., 2020) and demonstrate substantial improvement compared to existing webcam eye-tracking solutions (Papoutsaki et al., 2017).

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The development of online research platforms has made data collection more efficient and representative of populations. However, these benefits have not been available for use with cognitive neuroscience tools such as electroencephalography (EEG). In this study, we introduce an approach for remote EEG data collection. We demonstrate how an experiment can be built via the EmotivPRO Builder and deployed to the EmotivLABS website where it can be completed by participants who own EMOTIV EEG headsets. To demonstrate the data collection technique, we collected EEG while participants engaged in a resting state task where participants sat with their eyes open and then eyes closed for 2 min each. We observed a significant difference in alpha power between the two conditions thereby demonstrating the well-known alpha suppression effect. Thus, we demonstrate that EEG data collection, particularly for frequency domain analysis, can be successfully conducted online.

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Online methods allow testing of larger, more diverse populations, with much less effort than in-lab testing. However, many psychophysical measurements, including visual crowding, require accurate eye fixation, which is classically achieved by testing only experienced observers who have learned to fixate reliably, or by using a gaze tracker to restrict testing to moments when fixation is accurate. Alas, both approaches are impractical online since online observers tend to be inexperienced, and online gaze tracking, using the built-in webcam, has a low precision (±4 deg, Papoutsaki et al., 2016). The EasyEyes open-source software reliably measures peripheral thresholds online with accurate fixation achieved in a novel way, without gaze tracking. EasyEyes tells observers to use the cursor to track a moving crosshair. At a random time during successful tracking, a brief target is presented in the periphery. The observer responds by identifying the target. To evaluate EasyEyes fixation accuracy and thresholds, we tested 12 naive observers in three ways in a counterbalanced order: first, in the lab, using gaze-contingent stimulus presentation (Kurzawski et al., 2023; Pelli et al., 2016); second, in the lab, using EasyEyes while independently monitoring gaze; third, online at home, using EasyEyes. We find that crowding thresholds are consistent (no significant differences in mean and variance of thresholds across ways) and individual differences are conserved. The small root mean square (RMS) fixation error (0.6 deg) during target presentation eliminates the need for gaze tracking. Thus, EasyEyes enables fixation-dependent measurements online, for easy testing of larger and more diverse populations.

Asunto(s)

Enfermedad de Alzheimer , Disfunción Cognitiva , Humanos , Disfunción Cognitiva/diagnóstico , Disfunción Cognitiva/psicología , Enfermedad de Alzheimer/diagnóstico , Pruebas Neuropsicológicas

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In developmental psychology, the widespread adoption of new methods for testing children does not typically occur over a matter of months. Yet, the COVID-19 pandemic and its associated social distancing requirements created a sudden need among many research groups to use a new method with which they had little or no experience: online testing. Here, we report results from a survey of 159 researchers detailing their early experiences with online testing. The survey approach allowed us to create a general picture of the challenges, limitations, and opportunities of online research, and it identified aspects of the methods that have the potential to impact interpretations of findings. We use the survey results to present considerations to improve online research practices.

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Objectives: Gay, bisexual and other men who have sex with men (GBM) are disproportionately affected by sexually transmitted and blood-borne infections (STBBI) due to stigma and other factors such as structural barriers, which delay STBBI testing in this population. Understanding acceptability of online testing is useful in expanding access in this population, thus we examined barriers to clinic-based testing, acceptability of a potential online testing model, and factors associated with acceptability among GBM living in Ontario. Methods: Sex Now 2019 was a community-based, online, bilingual survey of GBM aged ≥15. Prevalence ratios (PR) and 95% confidence intervals (95%CI) were calculated using modified Poisson regression with robust variances. Multivariable modelling was conducted using the Hosmer-Lemeshow-Sturdivant approach. Results: Among 1369 participants, many delayed STBBI testing due to being too busy (31%) or inconvenient clinic hours (29%). Acceptability for online testing was high (80%), with saving time (67%) as the most common benefit, and privacy concerns the most common drawback (38%). Statistically significant predictors of acceptability for online testing were younger age (PR = 0.993; 95%CI: 0.991-0.996); a greater number of different sexual behaviours associated with STBBI transmission (PR = 1.031; 95%CI: 1.018-1.044); identifying as an Indigenous immigrant (PR = 1.427; 95%CI: 1.276-1.596) or immigrant of colour (PR = 1.158; 95%CI: 1.086-1.235) compared with white non-immigrants; and currently using HIV pre-exposure prophylaxis (PrEP) compared to not currently using PrEP (PR = 0.894; 95%CI: 0.828-0.965). Conclusions: Acceptability of online testing was high among GBM in Ontario. Implementing online STBBI testing may expand access for certain subpopulations of GBM facing barriers to current in-person testing.

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This work describes the implementation of online timed closed-book formative assessments across several modules of a first-year undergraduate veterinary program. This process does not require significant time investment since it can be implemented into existing programs of study. Students were surveyed on how they used these formative assessments for learning and overall, were overwhelmingly positive about the opportunity to practice and receive feedback on their performance. Quantitative statistics on preferences as well as qualitative thematic analysis of open free-text questions reveal clear preferences in how they choose to engage with the assessments for learning, as well as how they prefer assessments to be administered. Students were positive about the online nature of the exams and prefer formative assessments to be distributed across the teaching semesters without any time restrictions, allowing them to be completed as and when they choose. Immediate feedback in the form of model answers is the students' preference, although some value signposting to relevant resources for further research. Furthermore, students report that they want more questions and tests to complement their learning, and overwhelming rely on guided and structured activities for learning and revision which will need to be balanced with opportunities to develop critical thinking and independent learning skills when studying in a professional course, given students are not likely to default into such behavior. This work models a process many curriculum designers have, and continue to undergo in higher education as online, hybrid, and blended approaches to teaching have received renewed interest.

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The timing of the developmental emergence of holistic face processing and its sensitivity to experience in early childhood are somewhat controversial topics. To investigate holistic face perception in early childhood, we used an online testing platform and administered a two-alternative forced-choice task to 4-, 5-, and 6-year-old children. The children saw pairs of composite faces and needed to decide whether the faces were the same or different. To determine whether experience with masked faces may have negatively affected holistic processing, we also administered a parental questionnaire to assess the children's exposure to masked faces during the COVID-19 pandemic. We found that all three age groups performed holistic face processing when the faces were upright (Experiment 1) but not when the faces were inverted (Experiment 2), that response accuracy increased with age, and that response accuracy was not related to degree of exposure to masked faces. These results indicate that holistic face processing is relatively robust in early childhood and that short-term exposure to partially visible faces does not negatively affect young children's holistic face perception.

Asunto(s)

COVID-19 , Desarrollo Infantil , Reconocimiento Facial , Pandemias , Reconocimiento Facial/fisiología , COVID-19/epidemiología , Humanos , Masculino , Femenino , Preescolar , Desarrollo Infantil/fisiología , Niño , Encuestas y Cuestionarios , Padres , Máscaras

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The Social Shapes Test (SST) is a measure of social intelligence which does not use human faces or rely on extensive verbal ability. The SST has shown promising validity among adults without autism spectrum disorder (ASD), but it is uncertain whether it is suitable for adults with ASD. We find measurement invariance between adults with (n = 229) or without ASD (n = 1,049) on the 23-item SST. We also find that adults without ASD score higher on the SST than adults with ASD (d = 0.21). We also provide two, 14-item versions which demonstrated good parallel test-retest reliability and are positively related to scores on the Frith-Happé task. The SST is suitable for remote, online research studies.