Recruitment of magnitude representations to understand graded words.

Language understanding and mathematics understanding are two fundamental forms of human thinking. Prior research has largely focused on the question of how language shapes mathematical thinking. The current study considers the converse question. Specifically, it investigates whether the magnitude representations that are thought to anchor understanding of number are also recruited to understand the meanings of graded words. These are words that come in scales (e.g., Anger) whose members can be ordered by the degree to which they possess the defining property (e.g., calm, annoyed, angry, furious). Experiment 1 uses the comparison paradigm to find evidence that the distance, ratio, and boundary effects that are taken as evidence of the recruitment of magnitude representations extend from numbers to words. Experiment 2 uses a similarity rating paradigm and multi-dimensional scaling to find converging evidence for these effects in graded word understanding. Experiment 3 evaluates an alternative hypothesis - that these effects for graded words simply reflect the statistical structure of the linguistic environment - by using machine learning models of distributional word semantics: LSA, word2vec, GloVe, counterfitted word vectors, BERT, RoBERTa, and GPT-2. These models fail to show the full pattern of effects observed of humans in Experiment 2, suggesting that more is needed than mere statistics. This research paves the way for further investigations of the role of magnitude representations in sentence and text comprehension, and of the question of whether language understanding and number understanding draw on shared or independent magnitude representations. It also informs the role of machine learning models in cognitive psychology research.

Magnitude of digital adaptability role: Stakeholder engagement and costless signaling in enhancing sustainable MSME performance.

This study investigates the relationship between stakeholder engagement, costless signaling, digital adaptability, and sustainable performance in micro, small, and medium enterprises (MSMEs). A quantitative research approach was employed, collecting data through questionnaires from respondents who were owners or representatives of MSMEs. Statistical analysis was conducted to test the research hypotheses. The findings revealed a significant positive impact of stakeholder engagement and costless signaling on sustainable performance in MSMEs. However, digital adaptability did not moderate the relationship between costless signaling and sustainable performance. The implications of this study suggest that MSMEs should prioritize stakeholder engagement and employ effective costless signaling strategies to enhance their sustainable performance. Support from the government and financial institutions is also crucial in facilitating these efforts. The study has limitations in terms of generalizability, and further research is needed with a broader scope and more in-depth methods to deepen the understanding of the influence of digital adaptability in the context of MSMEs.

Towards unbiased interpretations of interactive effects in ecotoxicological studies.

Ecotoxicological research has increasingly focused on the interactive effects of chemical mixtures on biological models, emphasising additive, synergistic, or antagonistic interactions. However, these combination studies often test chemicals at unique concentrations (e.g. x:y), limiting our understanding of the effects across the full spectrum of possible combinations. Evidence from human toxicology suggests that interactive effects among chemicals can vary significantly with total concentration (e.g. x:y vs. 2x:2y), their ratio (e.g. x:2y vs. 2x:y), and the magnitude of the tested effect (e.g. LC10vs. LC50). Our non-exhaustive review of studies on binary mixtures in bee ecotoxicology reveals that such parameters are frequently neglected. Of the 60 studies we examined, only two utilised multiple total concentrations and ratios, thus exploring a broad range of possible combinations. In contrast, 26 studies tested only a single concentration of each chemical, resulting in incomplete interpretations of the potential interactive effects. Other studies utilised various concentrations and/or ratios but failed to capture a broad spectrum of possible combinations. We also discuss potential discrepancies in interactive effects based on different metrics and exposure designs. We advocate for future ecotoxicological studies to investigate a wider spectrum of chemical combinations, including various concentrations and ratios, and to address different levels of effects.

On the relativity of magnitudes: Delboeuf's forgotten contribution to the 19th century problem of space.

Faced with the mathematical possibility of non-Euclidean geometries, 19th Century geometers were tasked with the problem of determining which among the possible geometries corresponds to that of our space. In this context, the contribution of the Belgian philosopher-mathematician, Joseph Delboeuf, has been unduly neglected. The aim of this essay is to situate Delboeuf's ideas within the context of the philosophies of geometry of his contemporaries, such as Helmholtz, Russell and Poincaré. We elucidate the central thesis, according to which Euclidean geometry is given special status on the basis of the relativity of magnitudes, we uncover its hidden history and show that it is defensible within the context of the philosophies of geometry of the epoch. Through this discussion, we also develop various ideas that have some relevance to present-day methods in gravitational physics and cosmology.

Enhancing fluid signal in driven-equilibrium short-TI inversion-recovery imaging with short TR times: A feasibility study.

PURPOSE: Fluid-sensitive turbo spin echo (TSE) MRI with short-TI inversion-recovery preparation for fat suppression (STIR) plays a critical role in the diagnostics of the musculoskeletal system (e.g., close to metal implants). Potential advantages of 3D acquisitions, however, are difficult to exploit due to long acquisition times. Shortening the TR incurs a signal loss, and a driven-equilibrium (DE) extension reduces fluid signal even further. METHODS: The phase of the flip-back pulse was changed by 180° relative to the conventional implementation (i.e., 90° along the positive x-axis (90°x) instead of -90°x). After signal modeling and numerical simulations, the modification was implemented in STIR-TSE sequences and tested on a clinical 3T system. Imaging was performed in the lumbar spine, and long-TR images without DE were acquired as reference. CSF SNR and fluid-muscle contrast were measured and compared between the sequences. Imaging was repeated in a metal implant phantom. RESULTS: A shortening of TR by 43%-57% reduced the CSF SNR by 39%-59%. A conventional DE module further reduced SNR to 26%-40%, whereas the modified DE recovered SNR to 59%-108% compared with the long-TR acquisitions. Fluid-tissue contrast was increased by about 340% with the modified DE module compared with the conventional extension. Similar results were obtained in implant measurements. CONCLUSIONS: The proposed DE element for TSE-STIR sequences has the potential to accelerate the acquisition of fluid-sensitive images. DE-STIR may work most efficiently for 3D acquisitions, in which no temporo-spatial interleaving of inversion and imaging pulses is possible.

Magnitude and angle dynamics in training single ReLU neurons.

Understanding the training dynamics of deep ReLU networks is a significant area of interest in deep learning. However, there remains a lack of complete elucidation regarding the weight vector dynamics, even for single ReLU neurons. To bridge this gap, our study delves into the training dynamics of the gradient flow w(t) for single ReLU neurons under the square loss, dissecting it into its magnitude ‖w(t)‖ and angle φ(t) components. Through this decomposition, we establish upper and lower bounds on these components to elucidate the convergence dynamics. Furthermore, we demonstrate the empirical extension of our findings to general two-layer multi-neuron networks. All theoretical results are generalized to the gradient descent method and rigorously verified through experiments.

Quantitative susceptibility mapping based basal ganglia segmentation via AGSeg: leveraging active gradient guiding mechanism in deep learning.

Background: With better visual contrast and the ability for magnetic susceptibility quantification analysis, quantitative susceptibility mapping (QSM) has emerged as an important magnetic resonance imaging (MRI) method for basal ganglia studies. Precise segmentation of basal ganglia is a prerequisite for quantification analysis of tissue magnetic susceptibility, which is crucial for subsequent disease diagnosis and surgical planning. The conventional method of localizing and segmenting basal ganglia heavily relies on layer-by-layer manual annotation by experts, resulting in a tedious amount of workload. Although several morphology registration and deep learning based methods have been developed to automate segmentation, the voxels around the nuclei boundary remain a challenge to distinguish due to insufficient tissue contrast. This paper proposes AGSeg, an active gradient guidance-based susceptibility and magnitude information complete (MIC) network for real-time and accurate basal ganglia segmentation. Methods: Various datasets, including clinical scans and data from healthy volunteers, were collected across multiple centers with different magnetic field strengths (3T/5T/7T), with a total of 210 three-dimensional (3D) susceptibility measurements. Manual segmentations following fixed rules for anatomical borders annotated by experts were used as ground truth labels. The proposed network took QSM maps and Magnitude images as two individual inputs, of which the features are selectively enhanced in the proposed magnitude information complete (MIC) module. AGSeg utilized a dual-branch architecture, with Seg-branch aiming to generate a proper segmentation map and Grad-branch to reconstruct the gradient map of regions of interest (ROIs). With the support of the newly designed active gradient module (AGM) and gradient guiding module (GGM), the Grad-branch provided attention guidance for the Seg-branch, facilitating it to focus on the boundary of target nuclei. Results: Ablation studies were conducted to assess the functionality of the proposed modules. Significant performance decrement was observed after ablating relative modules. AGSeg was evaluated against several existing methods on both healthy and clinical data, achieving an average Dice similarity coefficient (DSC) =0.874 and average 95% Hausdorff distance (HD95) =2.009. Comparison experiments indicated that our model had superior performance on basal ganglia segmentation and better generalization ability over existing methods. The AGSeg outperformed all implemented comparison deep learning algorithms with average DSC enhancement ranging from 0.036 to 0.074. Conclusions: The current work integrates a deep learning-based method into automated basal ganglia segmentation. The high processing speed and segmentation robustness of AGSeg contribute to the feasibility of future surgery planning and intraoperative navigation. Experiments show that leveraging active gradient guidance mechanisms and magnitude information completion can facilitate the segmentation process. Moreover, this approach also offers a portable solution for other multi-modality medical image segmentation tasks.

Extent of magnitude representation deficit and relationship with arithmetic skills in children with 22q11.2DS.

BACKGROUND: Previous studies have produced conflicting results concerning the extent of magnitude representation deficit and its relationship with arithmetic achievement in children with 22q11.2 deletion syndrome. More specifically, it remains unclear whether deficits are restricted to visuospatial content or are more general and whether they could explain arithmetical impairment. METHODS: Fifteen 5- to 12-year-old children with 22q11.2 deletion syndrome and 23 age-matched healthy controls performed a non-symbolic magnitude comparison task. Depending on the trial, participants had to compare stimuli with high or low visuospatial load (visuospatial stimuli or temporal sequence of visual stimuli). The participants also completed a battery of arithmetic skills (ZAREKI-R) and a battery of global cognitive functioning (WISC-V or WPPSI-IV), from which working memory and visuospatial indices were derived. RESULTS: Children with 22q11.2DS responded as fast as healthy controls did but received fewer correct responses, irrespective of visuospatial load. In addition, their performance in the non-symbolic magnitude comparison task did not correlate with the ZAREKI total score, while the working memory index did. CONCLUSION: Children with 22q11.2DS might suffer from a global magnitude representation deficit rather than a specific deficit due to visuospatial load. However, this deficit alone does not seem to be related to arithmetic achievement. Working memory might be a better concern of interest in favoring arithmetic skills in patients with 22q11.2 deletion syndrome. TRIAL REGISTRATION: Clinicaltrials, NCT04373226 . Registered 16 September 2020.

Development of number line estsimation in Chinese preschoolers: a comparison between numerical and non-numerical symbols.

To examine the level of number line estimation (NLE) in Chinese children with respect to representations of both numerical (Arabic numerals) and non-numerical symbols (dots), a total of 192 Chinese preschoolers aged between 4 and 5 years participated in four different NLE tasks. These tasks were paired to evaluate the accuracy and patterns of children's estimations in both numerical and non-numerical symbol contexts. Our findings indicate that, for Chinese preschoolers, relatively precise numerical symbol representations begin to emerge as early as 4 years of age. The accuracy of number line estimates for both 4- and 5-year-old children gradually increases in tasks involving both numerical and non-numerical symbols. Additionally, the development and patterns observed in the number line estimates of 4- and 5-year-old Chinese preschoolers are similar in both numerical symbol and non-numerical symbol tasks. These results indicate that the initiation of relatively precise numerical symbol representation and the turning point in the developmental trajectory, where the relatively precise representation for numerical symbols surpasses that of non-numerical ones, occur earlier in Chinese children than in their Western counterparts.

The magnitude and associated factors of unused medications storage practice among households in Jimma city, southwest of Ethiopia: Community-based cross-sectional study.

Background: Medicines are kept unused at home for many therapeutic reasons. Conversely, unused medication and subsequent wastage can be attributed to several primary factors such as medication change, death, and non-adherence. This study aimed to assess the magnitude and associated factors of unused medication storage practice among households in Jimma City, southwest Ethiopia. Methods: A community-based cross-sectional study design was conducted among households (n = 397) in Jimma Town from July to August 2021. The data were collected using the pre-tested and interviewer-administered questionnaire. SPSS version 21.0 was used for data analysis. The multivariate logistic regression was used to determine the factors associated with the storage of unused medicine at a 5% level of significance. Results: Out of 397 households that responded, (n = 90, 23%) of households were found to have unused medicine at home. This study showed that the majority of households dispose of unused drugs by burning them (32.2%) and burying them in the ground (29%). Antibiotics were the most (6.3%) unused medicines stored while the anti-diabetics (1.3%) were the least unused drugs stored among households. The presence of family members working in the health sector (AOR: 0.402, 95%, CI: 0.202, 0.800) and family size in households (AOR: 2.325, 95%, CI: 1.045, 5.174) were significantly associated with the magnitude of unused medicine storage. Conclusion: The magnitude and improper disposal of unused medicines storage among households were significant in the study area. Therefore, it is important to educate the community and encourage health professionals to understand their role in problems and solutions.

Magnitude and outcome of road traffic accidents among patients admitted in dessie town governmental hospitals, Northeast Amhara, Ethiopia, 2022.

BACKGROUND: Road traffic accidents(RTA) are a major public health problem worldwide, accounting for almost 1.24 million deaths per year and it is the number one cause of death among those aged group 15-29 years. Even though there are great benefits from access to road transportation there also poses a great challenge in the individual's daily activities ranging from minor injury to death. OBJECTIVE: This study aimed to assess the magnitude and outcome of road traffic accidents among patients admitted in Dessie Town Governmental Hospitals, Northeast Amhara, Ethiopia, 2022. METHODS: A five-year hospital-based retrospective descriptive cross-sectional study design was conducted among 377 road traffic accident patients admitted to Dessie Town Governmental hospitals. Data were collected by simple random methods based on patient chart reviews from June 7/, 2022 to May 23/ 2017 using a checklist adapted from the WHO standard hospital-based road traffic accident questionnaires after obtaining consent from the concerned authority. EPI-Data software version 7.2 for data entry and SPSS version 25 for statistical analysis were used. Descriptive and inferential statistics were used. Statistical significance was declared at a p-value of < 0.05 with an adjusted odds ratio (AOR) and a 95% confidence interval (CI) in the final multinomial logistic regression model. RESULTS: The magnitude of road traffic accidents was 59%, using of logistic multi nominal logistic regression we found results such that, road traffic victims who had unstable vital signs at admission (AOR = 6.4,95% CI; 2.5-16.6), didn't get prehospital treatment (AOR = 9.3,95% CI; 4-20), and severe injury (AOR = 9, 95% CI;7-15.4), had a Glasgow coma scale of 3-5 (AOR = 5.2,95% CI; 1.4-20) were found predictors for death were as unstable vital signs at admission (AOR = 3.79,95%CI;2.1-6.8), Doesn't get prehospital treatment (AOR = 2.8, 95% CI; 1.4-5.7), Hospital stay for one to two months duration (AOR = 6,95% CI;2.3-15), and greater than two months duration (AOR = 6.5,95%CI;2.5-17) were found predictors for disability among road traffic victims. CONCLUSIONS AND RECOMMENDATIONS: Road traffic accidents constitute a major public health problem in our setting and contribute significantly to excessively high morbidity and mortality. Unstable vital signs at admission, Client doesn't get prehospital treatment, severely injured client, and had a Glasgow coma scale of 3-5 were found predictors for death were as an unstable vital sign at admission, Client doesn't get pre-hospital treatment, Hospital stays for one to two months duration, and greater than two months duration were found predictors for disability among road traffic victims.

Magnitude of emergence agitation, its interventions and associated factors among paediatric surgical patients.

BACKGROUND: Emergence agitation is a transient confusional state of a child associated with consciousness from general anaesthesia, commonly occurs in the postoperative setting which delays their recovery and exposes them to traumas. The main objective of the current study was to investigate the magnitude of emergence agitation, its interventions and associated factors among paediatric surgical patients at Saint Paul's Hospital Millennium Medical College, Addis Ababa, Ethiopia. METHODS: Hospital based cross-sectional study with prospective follow-up framework was conducted on a paediatric surgical patients aged 2-14 years who underwent surgery under general anaesthesia between June 1 - October 30 2022. Stratified sampling method followed by simple random sampling technique was employed to reach study participants. Magnitude of emergence agitation and its interventions done at post-anaesthetic care units were recorded. Data analysis was carried out using a descriptive statistics method and the results were summarized using tables and diagrams. Bivariate analysis was done to identify causal relationship and multivariable analysis to assess the confounding effects of factors associated with emergence agitation. A p-value of less than 0.05 was considered statistically significant factor. RESULTS: A total of 150 participants were included in the current study, where 107 (71.3%) were male and 97 (64.7%) were preschool aged. About 81 (54%) of care givers were female and majority of them have completed primary school. The mean (standard deviation) age of the participants was 6.4 (3.57) years. Around 42.7% of them developed emergence agitation with an average duration of 8.39 ± 4.45 minutes. Factors such as propofol administration at the end of procedure (OR of 0.104 with 95% CI [0.035, 0305]), Ear, nose, throat surgery and oral maxillofacial surgery (OR of 2.341 with 95% CI [1.051, 5.211]) and arrival of patient to recovery awake (OR of 0.456 95% CI [0.209, 0.994]) showed statistically significant association with emergence agitation. CONCLUSION: Almost half of the study participants experienced emergence agitation which is high magnitude. Ear, nose, throat surgery and oral maxillofacial surgeries were predictive factors of emergence agitation while propofol administration at the end of procedure and arrival of patient to recovery awake significantly decreased risk of emergence agitation. Therefore, anaesthesia personnel should have essential skills and knowledge to effectively care for children perioperatively including to minimize and treat emergence agitation.

Magnitude and associated factors of intraoperative hypothermia among pediatric patients undergoing elective surgery at Ayder Comprehensive Specialized Hospital 2023: prospective observational cross-sectional study Tigray, Ethiopia.

Background: Hypothermia is characterized by a drop in core body temperature of less than 36°C. It occurs frequently throughout the operating period and affects surgical patient outcomes differently in terms of morbidity and mortality. Because of coagulopathy, metabolic acidosis, multiple organ failure, hemodynamic instability, and infections, a core temperature below 34°C is strongly associated with mortality. Objective: This study aimed to assess the magnitude and associated factors of intraoperative hypothermia in pediatric patients undergoing elective surgery at the Ayder Comprehensive Specialized Hospital. Method: A prospective observational cross-sectional study was conducted on 399 pediatric patients undergoing elective surgery at Ayder Comprehensive Specialized Hospital in Tigray, Ethiopia, from 1 May 2023, to 30 July 2023. Participants in the study were selected by a systematic random sampling technique. The data collection procedure was chart review and intraoperative temperature measurement, and the collected data were analyzed by SPSS version 23. The independent variables were analyzed using binary and multi-logistic regression. The odds ratio, 95% CI, and p value of less than 0.05 were considered statistical significance. Result: The magnitude of intraoperative hypothermia was 52.9%. Neonate and infant [adjusted odds ratio (AOR): 6, 95% CI: 3.7, 9.8], (AOR=4.5, 95% CI: 2.9, 7) respectively, volume of fluid administered greater than half-liter [AOR: 4.37, (95% CI, 3, 6.4)], patients who underwent surgery during the morning [AOR: 5.3, (95% CI: 3.8, 7.4)], and duration of surgery and anesthesia greater than 120 minutes [AOR: 2.7, (95% CI, 1.8, 4)] and (AOR=3.4, 95% CI, 2.4, 4.9], respectively, were factors significantly associated with intraoperative hypothermia. Conclusion and recommendation: This study revealed a high magnitude of intraoperative hypothermia among pediatric patients. Being neonates and infants, having a cold volume of IV fluid administered greater than half a liter, entering surgery during the morning, the duration of surgery, and the anesthesia time were significantly associated with intraoperative hypothermia. The authors would like to advise anesthetists to use warm intravenous fluids, calculate IV fluids, and maintain room temperature.

Results of the cyclic triaxial testing on mechanically-biologically treated waste.

Accurate assessment of the dynamic strength characteristics of mechanically-biologically treated (MBT) waste is crucial for the construction and safe operation of landfill sites. Herein, samples of MBT waste from the Hangzhou Tianziling landfill were collected and subjected to consolidated undrained cyclic triaxial tests under four confinement levels and six cyclic stress ratios (CSRs). Under cyclic loading, the MBT waste exhibited a critical CSR. If the CSR exceeds the critical value, the MBT waste specimen rapidly undergoes deformation and failure. Dynamic strength of MBT waste decreases with an increase in the number of cyclic vibrations and increases with an increase in confining pressure. Considering the influence of cyclic vibrations and confining pressure, a formula for dynamic strength in terms of cyclic vibrations and confining pressure has been established. The dynamic shear strength parameter ranges for MBT waste were obtained under different seismic magnitudes. We compared the dynamic and static shear strength parameters of MBT waste and municipal solid waste. These study findings can serve as a reference for the dynamic stability analysis of MBT waste landfills.

Frontoparietal and salience network synchronizations during nonsymbolic magnitude processing predict brain age and mathematical performance in youth.

The development and refinement of functional brain circuits crucial to human cognition is a continuous process that spans from childhood to adulthood. Research increasingly focuses on mapping these evolving configurations, with the aim to identify markers for functional impairments and atypical development. Among human cognitive systems, nonsymbolic magnitude representations serve as a foundational building block for future success in mathematical learning and achievement for individuals. Using task-based frontoparietal (FPN) and salience network (SN) features during nonsymbolic magnitude processing alongside machine learning algorithms, we developed a framework to construct brain age prediction models for participants aged 7-30. Our study revealed differential developmental profiles in the synchronization within and between FPN and SN networks. Specifically, we observed a linear increase in FPN connectivity, concomitant with a decline in SN connectivity across the age span. A nonlinear U-shaped trajectory in the connectivity between the FPN and SN was discerned, revealing reduced FPN-SN synchronization among adolescents compared to both pediatric and adult cohorts. Leveraging the Gradient Boosting machine learning algorithm and nested fivefold stratified cross-validation with independent training datasets, we demonstrated that functional connectivity measures of the FPN and SN nodes predict chronological age, with a correlation coefficient of .727 and a mean absolute error of 2.944 between actual and predicted ages. Notably, connectivity within the FPN emerged as the most contributing feature for age prediction. Critically, a more matured brain age estimate is associated with better arithmetic performance. Our findings shed light on the intricate developmental changes occurring in the neural networks supporting magnitude representations. We emphasize brain age estimation as a potent tool for understanding cognitive development and its relationship to mathematical abilities across the critical developmental period of youth. PRACTITIONER POINTS: This study investigated the prolonged changes in the brain's architecture across childhood, adolescence, and adulthood, with a focus on task-state frontoparietal and salience networks. Distinct developmental pathways were identified: frontoparietal synchronization strengthens consistently throughout development, while salience network connectivity diminishes with age. Furthermore, adolescents show a unique dip in connectivity between these networks. Leveraging advanced machine learning methods, we accurately predicted individuals' ages based on these brain circuits, with a more mature estimated brain age correlating with better math skills.

Building integrated number sense in adults and children: Comparing fractions-only training with cross-notation number line training.

Mounting evidence points to the predictive power of cross-notation rational number understanding (e.g., 2/5 vs. 0.25) relative to within-notation understanding (e.g., 2/5 vs. 1/4) in predicting math outcomes. Although correlational in nature, these studies suggest that number sense training emphasizing integrating across notations may have more positive outcomes than a within-notation focus. However, this idea has not been empirically tested. Thus, across two studies with undergraduate students (N = 183 and N = 181), we investigated the effects of a number line training program using a cross-notation approach (one that focused on connections among fractions, decimals, and percentages) and a within-notation approach (one that focused on fraction magnitude representation only). Both number line approaches produced positive effects, but those of the cross-notation approach were larger for fraction magnitude estimation and cross-notation comparison accuracy. In a third study (N = 63), we adapted the cross-notation number line training for use in place of typical classroom warm-up activities for middle school students. Similar to the results with undergraduate students, the cross-notation training program yielded positive benefits for middle school students over a typical warm-up activity (fraction arithmetic practice). Together, these results suggest the importance of an integrated approach to teaching rational number notations, an approach that appears to be uncommon in current curricula.

Multiplexing intensity and frequency sensations for artificial touch by modulating temporal features of electrical pulse trains.

In neural prostheses, intensity modulation of a single channel (i.e., through a single stimulating electrode) has been achieved by increasing the magnitude or width of each stimulation pulse, which risks eliciting pain or paraesthesia; and by changing the stimulation rate, which leads to concurrent changes in perceived frequency. In this study, we sought to render a perception of tactile intensity and frequency independently, by means of temporal pulse train patterns of fixed magnitude, delivered non-invasively. Our psychophysical study exploits a previously discovered frequency coding mechanism, where the perceived frequency of stimulus pulses grouped into periodic bursts depends on the duration of the inter-burst interval, rather than the mean pulse rate or periodicity. When electrical stimulus pulses were organised into bursts, perceived intensity was influenced by the number of pulses within a burst, while perceived frequency was determined by the time between the end of one burst envelope and the start of the next. The perceived amplitude was modulated by 1.6× while perceived frequency was varied independently by 2× within the tested range (20-40 Hz). Thus, the sensation of intensity might be controlled independently from frequency through a single stimulation channel without having to vary the injected electrical current. This can form the basis for improving strategies in delivering more complex and natural sensations for prosthetic hand users.

An improved method to measure transfer functions using MRI.

PURPOSE: A previously published method for MRI-based transfer function assessment makes use of the so-called transceive phase assumption (TPA). This limits its applicability to shorter leads and/or lower field strengths. A new method is presented where the background electric field is determined from both B 1 + $$ {\mathrm{B}}_1^{+} $$ - and B 1 - $$ {\mathrm{B}}_1^{-} $$ -field distributions, avoiding the TPA and making it more generally applicable. THEORY AND METHODS: These B 1 $$ {\mathrm{B}}_1 $$ -distributions are determined from a spoiled gradient echo multiflip angle acquisition. From the separated B 1 $$ {\mathrm{B}}_1 $$ -components the background electrical field and the induced current are computed. Further improvement is achieved by recasting the B 1 $$ {\mathrm{B}}_1 $$ -field model as a "magnitude squared least squares" problem. The proposed reconstruction method is used to determine transfer functions of various copper wire lengths up to 40 cm inside an elliptical ASTM phantom. The method is first tested on EM-simulated data and subsequently phantom and bench measurements are used to determine transfer functions experimentally. RESULTS: In silica reconstructions demonstrate the validity of the proposed B 1 $$ {\mathrm{B}}_1 $$ -field model resulting in highly accurate reconstructed B 1 $$ {\mathrm{B}}_1 $$ -fields, currents, incident electric fields and transfer functions. The experimental results show slight deviations in the field model, however, resulting transfer functions are accurately determined with high similarity to simulations and comparable to bench measurements. CONCLUSION: A more generally applicable method for MRI-based transfer function assessment is presented. The proposed method circumvents phase assumptions making it applicable for longer objects and/or higher field strengths. Additional improvements are implemented in the B 1 $$ {\mathrm{B}}_1 $$ -mapping method and the solution algorithm.

Inferring maximum magnitudes from the ordered sequence of large earthquakes.

The largest magnitude earthquake in a sequence is often used as a proxy for hazard estimates, as consequences are often predominately from this single event (in small seismic zones). In this article, the concept of order statistics is adapted to infer the maximum magnitude ([Formula: see text]) of an earthquake catalogue. A suite tools developed here can discern [Formula: see text] influences through hypothesis testing, quantify [Formula: see text] through maximum likelihood estimation (MLE) or select the best [Formula: see text] prediction amongst several models. The efficacy of these tools is benchmarked against synthetic and real-data tests, demonstrating their utility. Ultimately, 13 cases of induced seismicity spanning wastewater disposal, hydraulic fracturing and enhanced geothermal systems are tested for volume-based [Formula: see text]. I find that there is no evidence of volume-based processes influencing any of these cases. On the contrary, all these cases are adequately explained by an unbounded magnitude distribution. This is significant because it suggests that induced earthquake hazards should also be treated as unbounded. On the other hand, if bounded cases exist, then the tools developed here will be able to discern them, potentially changing how an operator mitigates these hazards. Overall, this suite of tools will be important for better-understanding earthquakes and managing their risks. This article is part of the theme issue 'Induced seismicity in coupled subsurface systems'.