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The key assumption of conditional independence of item responses given latent ability in item response theory (IRT) models is addressed for multistage adaptive testing (MST) designs. Routing decisions in MST designs can cause patterns in the data that are not accounted for by the IRT model. This phenomenon relates to quasi-independence in log-linear models for incomplete contingency tables and impacts certain types of statistical inference based on assumptions on observed and missing data. We demonstrate that generalized residuals for item pair frequencies under IRT models as discussed by Haberman and Sinharay (J Am Stat Assoc 108:1435–1444, 2013. https://doi.org/10.1080/01621459.2013.835660) are inappropriate for MST data without adjustments. The adjustments are dependent on the MST design, and can quickly become nontrivial as the complexity of the routing increases. However, the adjusted residuals are found to have satisfactory Type I errors in a simulation and illustrated by an application to real MST data from the Programme for International Student Assessment (PISA). Implications and suggestions for statistical inference with MST designs are discussed.
We propose a generalization of the speed–accuracy response model (SARM) introduced by Maris and van der Maas (Psychometrika 77:615–633, 2012). In these models, the scores that result from a scoring rule that incorporates both the speed and accuracy of item responses are modeled. Our generalization is similar to that of the one-parameter logistic (or Rasch) model to the two-parameter logistic (or Birnbaum) model in item response theory. An expectation–maximization (EM) algorithm for estimating model parameters and standard errors was developed. Furthermore, methods to assess model fit are provided in the form of generalized residuals for item score functions and saddlepoint approximations to the density of the sum score. The presented methods were evaluated in a small simulation study, the results of which indicated good parameter recovery and reasonable type I error rates for the residuals. Finally, the methods were applied to two real data sets. It was found that the two-parameter SARM showed improved fit compared to the one-parameter SARM in both data sets.
The crystal structure of perfluorononanoic acid (PFNA) was solved via parallel tempering using synchrotron powder diffraction data obtained from the Brockhouse X-ray Diffraction and Scattering (BXDS) Wiggler Lower Energy (WLE) beamline at the Canadian Light Source. PFNA crystallizes in monoclinic space group P21/c (#14) with lattice parameters a = 26.172(1) Å, b = 5.6345(2) Å, c = 10.9501(4) Å, and β = 98.752(2)°. The crystal structure is composed of dimers, with pairs of PFNA molecules connected by hydrogen bonds via the carboxylic acid functional groups. The Rietveld-refined structure was compared to a density functional theory-optimized structure, and the root-mean-square Cartesian difference was larger than normally observed for correct powder structures. The powder data likely exhibited evidence of disorder which was not successfully modeled.
We performed a knowledge, attitudes, and practice (KAP) survey of bedside nurses to evaluate perceptions of antimicrobial use and aid in the design of nursing-based antimicrobial stewardship interventions. The survey highlighted discrepancies in knowledge and practice as well as opportunities to improve communication with nursing colleagues.
Up to 60% of people with dementia living in care homes will ‘wander’ (i.e. walk without a clear purpose) at some point, which may occur due to cognitive changes, issues with orientation or lifelong habits. Nonpharmacological interventions are considered the best approach to supporting wandering as they aim to address underlying causes while posing minimal risk to the individual. However, there are many benefits to wandering safely in care homes, including physical benefits of exercise, retaining autonomy over location, and maintaining self-identity. This study aimed to develop evidence to understand the perspectives of care home staff around wandering as a meaningful activity. Specifically, we sought to identify: i) attitudes towards wandering; ii) the barriers and facilitators to supporting wandering in the care home; and iii) support needs to implement strategies across different care home contexts.
We conducted 20 semi-structured interviews with staff members including direct care staff, registered nurses, managers, and activities coordinators. Participants were recruited from a range of care homes across North England who provide care for older adults living with dementia, using purposive sampling to recruit participants with a range of experiences. Data were analyzed using framework analysis, a form of thematic analysis.
Four main themes were identified and refined by the wider research team. The impact of the environment on how residents moved around the care home, the importance of life history and personhood for staff to understand the motivations residents had for wandering, individual factors that contributed to each resident’s unique experiences and the importance of the care home culture to whether residents were supported. Participants also highlighted a range of strategies that they engage with to support residents to wander safely.
Although this was a small-scale study, conducted in one region of England, it has implications for the ways that wandering as a behavior is conceptualized and supported in care homes. The importance of language and vocabulary was highlighted and requires further consideration. The results of this study will be used to develop further work to test strategies in care homes and produce guidelines for supporting residents to wander safely.
Salmonella enterica continues to be a leading cause of foodborne morbidity worldwide. A quantitative risk assessment model was developed to evaluate the impact of pathogen enumeration and serotyping strategies on public health after consumption of undercooked contaminated ground turkey in the USA. The risk assessment model predicted more than 20,000 human illnesses annually that would result in ~700 annual reported cases. Removing ground turkey lots contaminated with Salmonella exceeding 10 MPN/g, 1 MPN/g, and 1 MPN/25 g would decrease the mean number of illnesses by 38.2, 73.1, and 95.0%, respectively. A three-class mixed sampling plan was tested to allow the detection of positive lots above threshold levels with 2–6 (c = 1) and 3–8 samples per lot (c = 2) using 25-g and 325-g sample sizes for a 95% probability of rejecting a contaminated lot. Removal of positive lots with the presence of highly virulent serotypes would decrease the number of illnesses by 44.2–87.0%. Based on these model prediction results, risk management strategies should incorporate pathogen enumeration and/or serotyping. This would have a direct impact on illness incidence linking public health outcomes with measurable food safety objectives, at the cost of diverting production lots.
Treatment of childhood central nervous system (CNS) tumors can lead to sensorineural hearing loss (SNHL), with prior research indicating associations between SNHL and cognitive difficulties. Infants (0-3 years) treated for CNS tumors are at particular risk for neurocognitive deficits due to increased vulnerability of the developing brain and missed developmental opportunities secondary to prolonged treatment. This study expands upon existing research by examining the association between treatment-related SNHL and later neurocognitive outcomes among infants.
Participants and Methods:
Serial audiology and neurocognitive assessments were conducted as part of a prospective, multisite, longitudinal trial (SJYC07). Children with newly diagnosed CNS tumors were treated with chemotherapy, with or without focal proton or photon radiation therapy (RT). SNHL was dichotomized based on hearing in the better ear as present versus not present (Chang grade ≥1a vs. <1a). Neurocognitive assessments included intellectual functioning (IQ), and parent ratings of executive functioning and behavioral functioning. Demographic and clinical variables investigated included: sex, age at diagnosis (years), treatment type (chemotherapy only vs. chemotherapy + RT), risk group (low vs. intermediate vs. high), and socioeconomic status (SES, continuous). Logistic regression models were used to identify factors associated with SNHL. Change point longitudinal models were used to examine the effect of each covariate individually and the potential impact of SNHL on trajectories of neurocognitive outcomes.
Results:
Of 135 patients (median age at diagnosis= 1.5 years), 67% had mild-to-severe SNHL as defined by Chang grade ≥1a at last follow-up. SNHL occurred early after treatment with a 1-year cumulative incidence 63.0% ±4.3%. SNHL was associated with age at diagnosis (p <.001) but not sex, treatment exposure or study risk arm (p >.10). At pretreatment baseline, IQ was associated with age at diagnosis (older age= higher IQ) and SES (higher SES= higher IQ) with a change in the trajectory of IQ after SNHL (stable prior to SNHL and declined 1.46 points/year after SNHL), which was impacted by tumor location (patients with supratentorial tumors stable prior to SNHL and declined 2.84 points/year after SNHL; whereas, patients with infratentorial tumors increased 1.93 points/year prior to SNHL and were stable after SNHL). At pre-treatment baseline, adaptive functioning was associated with age at diagnosis (older age= higher skills) with a change in adaptive functioning after SNHL that varied by age. There was a change in trajectory of attention problems (stable before SNHL and worsening 1.39 points/year after SNHL). SNHL was not associated with parent report of emerging executive functioning.
Conclusions:
Children with brain tumors experience SNHL and cognitive difficulties early in treatment that can worsen over time. Younger age at diagnosis is associated with greater risk for SNHL and cognitive difficulties. Analyses of the time course between the emergence of SNHL and cognitive late effects suggests even mild SNHL is associated with a clinically signficant decline in IQ and attention problems. These findings have notable implications with respect to refining monitoring guidelines, informing modifications to treatment, advocating for interventions, and helping educate parents, teachers, and providers about the significant impact of mild SNHL.
Generalized anxiety disorder (GAD) is a highly prevalent mental illness that is associated with clinically significant distress, functional impairment, and poor emotional regulation. Primary functional magnetic resonance imaging (fMRI) studies of GAD report neural abnormalities in comparison to healthy controls. However, many of these findings in the primary literature are inconsistent, and it is unclear whether they are specific to GAD or shared transdiagnostically across related disorders.
Objectives
This meta-analysis seeks to establish the most reliable neural abnormalities observed in individuals with GAD, as reported in the primary fMRI activation literature.
Methods
We conducted an exhaustive literature search in PubMed to identify primary studies that met our pre-specified inclusion criteria and then extracted relevant data from primary, whole-brain fMRI activation studies of GAD that reported coordinates in Talairach or MNI space. We then used multilevel kernel density analysis (MKDA) with ensemble thresholding to examine the differences between adults with GAD and healthy controls in order to identify brain regions that reached statistical significance across primary studies.
Results
Patients with GAD showed statistically significant (α=0.05–0.0001; family-wise-error-rate corrected) neural activation in various regions of the cerebral cortex and basal ganglia across a variety of experimental tasks.
Conclusions
These results inform our understanding of the neural basis of GAD and are interpreted using a frontolimbic model of anxiety as well as specific clinical symptoms of this disorder and its relation to other mood and anxiety disorders. These results also suggest possible novel targets for emerging neurostimulation therapies (e.g., transcranial magnetic stimulation) and may be used to advance our understanding of the effects of current pharmaceutical treatments and ways to improve treatment selection and symptom-targeting for patients diagnosed with GAD.
Functional magnetic resonance imaging (fMRI) has been used to identify the neural activity of both youth and adults diagnosed with major depressive disorder (MDD) in comparison to healthy age-matched controls. Previously reported abnormalities in depressed youth appear to mostly align with those found in depressed adults; however, some of the reported aberrant brain activity in youth has not been consistent with what is observed in adults, and to our knowledge there has not yet been a formal, quantitative comparison of these two groups. In addition, it is not known whether these observed differences between youth and adults with depression are attributable to developmental age or length-of-illness.
Objectives
The aim of this study is to elucidate the similarities and differences in patterns of abnormal neural activity between adults and youth diagnosed with MDD and to then determine whether these observed differences are due to either developmental age or length-of-illness.
Methods
We used multilevel kernel density analysis (MKDA) with ensemble thresholding and triple subtraction to separately determine neural abnormalities throughout the whole brain in primary studies of depressed youth and depressed adults and then directly compare the observed abnormalities between each of those age groups. We then conducted further comparisons between multiple subgroups to control for age and length-of-illness and thereby determine the source of the observed differences between youth and adults with depression.
Results
Adults and youth diagnosed with MDD demonstrated reliable, differential patterns of abnormal activation in various brain regions throughout the cerebral cortex that are statistically significant (p < .05; FWE-corrected). In addition, several of these brain regions that exhibited differential patterns of neural activation between the two age groups can be reliably attributed to either developmental age or length-of-illness.
Conclusions
These findings indicate that there are common and disparate patterns of brain activity between youth and adults with MDD, several of which can be reliably attributed to developmental age or length-of-illness. These results expand our understanding of the neural basis of depression across development and course of illness and may be used to inform the development of new, age-specific clinical treatments as well as prevention strategies for this disorder.
Major depressive disorder (MDD) is a highly prevalent mental illness that frequently originates in early development and is pervasive during adolescence. Despite its high prevalence and early age of onset, our understanding of the potentially unique neural basis of MDD in this age group is still not well understood, and the existing primary literature on the topic includes many new and divergent results. This limited understanding of MDD in youth presents a critical need to further investigate its neural basis in youth and presents an opportunity to also improve clinical treatments that target its neural abnormalities.
Objectives
The present study aims to advance our understanding of the neural basis of MDD in youth by identifying abnormal functional activation in various brain regions compared with healthy controls.
Methods
We conducted a meta-analysis of functional magnetic resonance imaging (fMRI) studies of MDD by using a well-established method, multilevel kernel density analysis (MKDA) with ensemble thresholding, to quantitatively combine all existing whole-brain fMRI studies of MDD in youth compared with healthy controls. This method involves a voxel-wise, whole-brain approach, that compares neural activation of patients with MDD to age-matched healthy controls across variations of task-based conditions, which we subcategorize into affective processing, executive functioning, positive valence, negative valence, and symptom provocation tasks.
Results
Youth with MDD exhibited statistically significant (p<0.05; FWE-corrected) hyperactivation and hypoactivation in multiple brain regions compared with age-matched healthy controls. These results include significant effects that are stable across various tasks as well as some that appear to depend on task conditions.
Conclusions
This study strengthens our understanding of the neural basis of MDD in youth and may also be used to help identify possible similarities and differences between youth and adults with depression. It may also help inform the development of new treatment interventions and tools for predicting unique treatment responses in youth with depression.
Curiosity toward the effects of psychedelic drugs on neural activation has increased due to their potential therapeutic benefits, particularly serotonergic psychedelics that act as 5-HT2A receptor agonists such as LSD, psilocybin, and MDMA. However, the pattern of their effects on neural activity in various brain regions in both clinical and healthy populations is still not well understood, and primary studies addressing this issue have sometimes generated inconsistent results.
Objectives
The present meta-analysis aims to advance our understanding of the most widely used serotonergic psychedelics – LSD, psilocybin, and MDMA – by examining their effects on the functional activation throughout the whole brain among both clinical and healthy participants.
Methods
We conducted this meta-analysis by applying multilevel kernel density analysis (MKDA) with ensemble thresholding to quantitatively combine existing functional magnetic resonance imaging (fMRI) studies that examined whole-brain functional activation of clinical or healthy participants who were administered a serotonergic psychedelic.
Results
Serotonergic psychedelics, including LSD, psilocybin, and MDMA, exhibited significant effects (α=0.05) on neural activation in several regions throughout the cerebral cortex and basal ganglia, including effects that may be common across and unique within each drug.
Conclusions
These observed effects of serotonergic psychedelics on neural activity advance our understanding of the functional neuroanatomy associated with their administration and may inform future studies of both their adverse and therapeutic effects, including emerging clinical applications for the treatment of several psychiatric disorders.
Major depressive disorder (MDD) is a highly prevalent mental illness that often first occurs or persists into adulthood and is considered the leading cause of disability and disease burden worldwide. Unfortunately, individuals diagnosed with MDD who seek treatment often experience limited symptom relief and may not achieve long-term remission, which is due in part to our limited understanding of its underlying pathophysiology. Many studies that use task-based functional magnetic resonance imaging (fMRI) have found abnormal activation in brain regions in adults diagnosed with MDD, but those findings are often inconsistent; in addition, previous meta-analyses that quantitatively integrate this large body literature have found conflicting results.
Objectives
This meta-analysis aims to advance our understanding of the neural basis of MDD in adults, as measured by fMRI activation studies, and address inconsistencies and discrepancies in the empirical literature.
Methods
We employed multilevel kernel density analysis (MKDA) with ensemble thresholding, a well-established method for voxel-wise, whole-brain meta-analyses, to conduct a quantitative comparison of all relevant primary fMRI activation studies of adult patients with MDD compared to age-matched healthy controls.
Results
We found that adults with MDD exhibited a reliable pattern of statistically significant (p<0.05; FWE-corrected) hyperactivation and hypoactivation in several brain regions compared to age-matched healthy controls across a variety of experimental tasks.
Conclusions
This study supports previous findings that there is reliable neural basis of MDD that can be detected across heterogenous fMRI studies. These results can be used to inform development of promising treatments for MDD, including protocols for personalized interventions. They also provide the opportunity for additional studies to examine the specificity of these effects among various populations-of-interest, including youth vs. adults with depression as well as other related mood and anxiety disorders.
Climate change has had a significant impact on glacier recession, particularly in the Arctic, where glacier meltwater is an important contributor to global sea-level rise. Therefore, it is important to accurately quantify glacier recession within this sensitive region, using multiple observations of glacier extent. In this study, we mapped 480 glaciers in Novaya Zemlya, Russian Arctic, using object-based image analysis applied to multispectral Landsat satellite imagery in Google Earth Engine and quantify the area changes between 1986–89 and 2019–21. The results show that in 1986–89, the total glacierized area was 22 990 ± 301 km2, in 2000–01 the area was 22 525 ± 308 km2 and by 2019–21 the glacier area reduced to 21 670 ± 292 km2, representing a total of 5.8% reduction in glacier area between 1986–89 and 2019–21. Higher glacier area loss was observed on the Barents Sea coast (7.3%) compared to the Kara (4.2%), reflecting previously observed differences in warming trends. The accuracy of the automatically generated outlines of each layer (1986–89, 2000–01 and 2019–21) was evaluated by comparing with manually corrected outlines (reference data) using random sampling, resulting in an overall accuracy estimate of between 96 and 97% compared to the reference data. This automated approach in Google Earth Engine is a promising tool for rapidly mapping glacier change that reduces the amount of time required to generate accurate glacier outlines.
During the coronavirus disease 2019 (COVID-19), individuals’ compliance with protective behaviors was the most effective strategy to break the infection chain and prevent disease spread, even with vaccine availability and use. Understanding protective behaviors within the Jordanian context will shape health promotion campaigns and guide decision-makers to facilitate required resources and support Jordanian citizens. The objective of this study was to identify personal protective (preventive and avoidant) measures used by the Jordanian population during the COVID-19 pandemic to protect themselves from infection.
Methods:
A cross-sectional study with an exploratory, descriptive design was used to collect data using an online self-reported questionnaire from Jordanian people. The survey included the Protection from Infection Scale and the Infection Avoidance Scale.
Results:
A total sample of 1053 Jordanian citizens was included in the study. The participants exhibited a moderate level of self-care behaviors and high levels of protective and infection avoidance behaviors. Their most common behaviors were getting enough sleep, wearing masks, washing hands, and avoiding travel to infected areas. Contrariwise, the least adopted behaviors were exercising, wearing gloves, and leaving their jobs or schools.
Conclusions:
During pandemics, policy-makers must understand public concerns and protective behaviors, then provide them with tailored education through health promotion campaigns to enhance healthy behaviors.
The recent development in the miniaturisation of small satellites and their subsystems has opened a new window of research for the universities around the globe. The low-cost, lightweight, small and flexible satellites have resulted in a broad range of multi-cube format small satellites, constructed from one-to-many adjoined cubes, having total mass between 1 and 10kg. The most challenging design part of the small satellites is to implant a large number of subsystems in a limited space. In order to resolve this issue, the designers are trying to shrink down the subsystem’s dimensions further. In this paper, a magnetorquer coil is designed and analysed for a 4U (4 units cube; 33 × 33 × 16.5)cm3 and 8U (8 units cube; 33 × 33 × 33)cm3 multi-cube small satellites, respectively. The coil is embedded in the six internal layers of an eight-layers printed circuit board (PCB). The designed magnetorquer system is fully reconfigurable and multiple coils configurations can be achieved by attaching them in series, parallel and hybrid arrangements. Due to embedded nature, the heat generated by the coil may damage the components mounted on the PCB outer surfaces. Therefore, thermal analysis is performed to ensure that the coil generated heat will not cross the PCB components temperature safety limits. All the possible combinations of the coils are analysed for current drawn, power consumption, heat dissipation, magnetic moment generation and resultant torque. A desired torque can be attained by using a particular coil configuration at the cost of specific amount of consumed power and PCB surface thermals.
Owing to its obvious cosmetic appeal, minimal invasive repair of congenital heart defects (CHDs) through the mini right axillary thoracotomy is becoming routine in many centres. Besides cosmesis, and before becoming a new norm, it is important to establish its outcomes as safe compared to repairs through traditional median sternotomy.
Methods:
Between 2013 and 2021, 116 consecutive patients underwent defect repairs through mini right axillary thoracotomy. Patient, operative data, and hospital outcomes were compared to contemporary mini right axillary thoracotomy and sternotomy series.
Results:
There was no mortality or need for approach conversion (mean age 4.3 years, range 0.17–17, mean weight 18.6 kg, range 4.8–74.4) in 118 repairs for atrial septal defect, ventricular septal defect, partial anomalous pulmonary venous return, partial atrioventricular canal with mitral cleft, scimitar syndrome, double-chambered right ventricle, cor triatriatum, and tricuspid valve repair. Protocol included on-table extubation, achieved in 97 children, with 23 outliers leading to 0.7 average hours of mechanical ventilation (range 0–66 hours), indwelling chest drain time of 2.6 days (range 1–9 days), intensive care stay of 1.8 days (range 1–10 days), and hospital stay of 3.9 days (range 2–18 days). Late revisions were required in one patient after scimitar repair for scimitar vein stenosis at 2 weeks, and in another for repair of superior caval vein stenosis after a Warden operation at 2 months; reoperations (5/116 = 4.3%) were successfully performed through the same mini right axillary incision.
Conclusions:
While providing obvious cosmetic advantages, the minimally invasive right axillary thoracotomy approach for the surgical repair of common CHDs yields excellent results and is safe compared to the benchmark median sternotomy approach.
Relapse and recurrence of depression are common, contributing to the overall burden of depression globally. Accurate prediction of relapse or recurrence while patients are well would allow the identification of high-risk individuals and may effectively guide the allocation of interventions to prevent relapse and recurrence.
Aims
To review prognostic models developed to predict the risk of relapse, recurrence, sustained remission, or recovery in adults with remitted major depressive disorder.
Method
We searched the Cochrane Library (current issue); Ovid MEDLINE (1946 onwards); Ovid Embase (1980 onwards); Ovid PsycINFO (1806 onwards); and Web of Science (1900 onwards) up to May 2021. We included development and external validation studies of multivariable prognostic models. We assessed risk of bias of included studies using the Prediction model risk of bias assessment tool (PROBAST).
Results
We identified 12 eligible prognostic model studies (11 unique prognostic models): 8 model development-only studies, 3 model development and external validation studies and 1 external validation-only study. Multiple estimates of performance measures were not available and meta-analysis was therefore not necessary. Eleven out of the 12 included studies were assessed as being at high overall risk of bias and none examined clinical utility.
Conclusions
Due to high risk of bias of the included studies, poor predictive performance and limited external validation of the models identified, presently available clinical prediction models for relapse and recurrence of depression are not yet sufficiently developed for deploying in clinical settings. There is a need for improved prognosis research in this clinical area and future studies should conform to best practice methodological and reporting guidelines.