The Simplest Solution to an Underdetermined System of Linear Equations

Consider a d*n matrix A, with d<n. The problem of solving for x in y=Ax is underdetermined, and has infinitely many solutions (if there are any). Given y, the minimum Kolmogorov complexity solution (MKCS) of the input x is defined to be an input z (out of many) with minimum Kolmogorov-complexity that satisfies y=Az. One expects that if the actual input is simple enough, then MKCS will recover the input exactly. This paper presents a preliminary study of the existence and value of the complexity level up to which such a complexity-based recovery is possible. It is shown that for the set of all d*n binary matrices (with entries 0 or 1 and d<n), MKCS exactly recovers the input for an overwhelming fraction of the matrices provided the Kolmogorov complexity of the input is O(d). A weak converse that is loose by a log n factor is also established for this case. Finally, we investigate the difficulty of finding a matrix that has the property of recovering inputs with complexity of O(d) using MKCS.Comment: Proceedings of the IEEE International Symposium on Information Theory Seattle, Washington, July 9-14, 200

Spatial and temporal clustering of dengue virus transmission in Thai villages.

BackgroundTransmission of dengue viruses (DENV), the leading cause of arboviral disease worldwide, is known to vary through time and space, likely owing to a combination of factors related to the human host, virus, mosquito vector, and environment. An improved understanding of variation in transmission patterns is fundamental to conducting surveillance and implementing disease prevention strategies. To test the hypothesis that DENV transmission is spatially and temporally focal, we compared geographic and temporal characteristics within Thai villages where DENV are and are not being actively transmitted.Methods and findingsCluster investigations were conducted within 100 m of homes where febrile index children with (positive clusters) and without (negative clusters) acute dengue lived during two seasons of peak DENV transmission. Data on human infection and mosquito infection/density were examined to precisely (1) define the spatial and temporal dimensions of DENV transmission, (2) correlate these factors with variation in DENV transmission, and (3) determine the burden of inapparent and symptomatic infections. Among 556 village children enrolled as neighbors of 12 dengue-positive and 22 dengue-negative index cases, all 27 DENV infections (4.9% of enrollees) occurred in positive clusters (p &lt; 0.01; attributable risk [AR] = 10.4 per 100; 95% confidence interval 1-19.8 per 100]. In positive clusters, 12.4% of enrollees became infected in a 15-d period and DENV infections were aggregated centrally near homes of index cases. As only 1 of 217 pairs of serologic specimens tested in positive clusters revealed a recent DENV infection that occurred prior to cluster initiation, we attribute the observed DENV transmission subsequent to cluster investigation to recent DENV transmission activity. Of the 1,022 female adult Ae. aegypti collected, all eight (0.8%) dengue-infected mosquitoes came from houses in positive clusters; none from control clusters or schools. Distinguishing features between positive and negative clusters were greater availability of piped water in negative clusters (p &lt; 0.01) and greater number of Ae. aegypti pupae per person in positive clusters (p = 0.04). During primarily DENV-4 transmission seasons, the ratio of inapparent to symptomatic infections was nearly 1:1 among child enrollees. Study limitations included inability to sample all children and mosquitoes within each cluster and our reliance on serologic rather than virologic evidence of interval infections in enrollees given restrictions on the frequency of blood collections in children.ConclusionsOur data reveal the remarkably focal nature of DENV transmission within a hyperendemic rural area of Thailand. These data suggest that active school-based dengue case detection prompting local spraying could contain recent virus introductions and reduce the longitudinal risk of virus spread within rural areas. Our results should prompt future cluster studies to explore how host immune and behavioral aspects may impact DENV transmission and prevention strategies. Cluster methodology could serve as a useful research tool for investigation of other temporally and spatially clustered infectious diseases

Development and preliminary results of an Electronic Medical Record (EMR)-integrated smartphone telemedicine program to deliver asthma care remotely

Background: Technology-based interventions that can function within real-world practice and improve outcomes without increasing provider burden are needed, yet few successfully cross the research-to-practice divide. This paper describes the process of developing a clinically-integrated smartphone-telemedicine program for adults with asthma and results from proof-of-concept testing. Methods: To ensure integration with practice, we used a contextually-grounded intervention development approach and May\u27s implementation theory to design the intervention, with emphasis on systems capabilities and stakeholder needs. The intervention incorporated symptom monitoring by smart phone, smartphone telemedicine visits and self-management training with a nurse, and clinical decision support software, which provided automated calculations of asthma severity, control, and step-wise therapy. Seven adults (aged 18-40) engaged in a 3-month beta-test. Asthma outcomes (control, quality of life, FEV1) and healthcare utilization patterns were measured at baseline and end-of-study. Results: Each participant received an average of 4 telemedicine visits with 94% patient satisfaction. All participants had uncontrolled asthma at baseline; by end-of-study 5/7 classified as well controlled. Mean asthma control improved 1.55 points (CI=0.59-2.51); quality of life improved 1.91 points CI=0.50-3.31), and FEV1 percent predicted increased 14.86% (CI=-3.09-32.80) with effect sizes of d=1.16, 1.09, and 0.96, respectively. Preventive healthcare utilization increased significantly (1.86 visits/year vs. 0.28/year prior, CI 0.67-2.47) as did prescriptions for controller medications (9.29 refills/year vs. 1.57 refills/year, CI 4.85-10.58) Conclusion: Smartphone telemedicine may be an effective means to improve outcomes and deliver asthma care remotely. However, careful attention to systems capabilities and stakeholder acceptability is needed to ensure successful integration with practice

Fine Scale Spatiotemporal Clustering of Dengue Virus Transmission in Children and Aedes aegypti in Rural Thai Villages

Background: Based on spatiotemporal clustering of human dengue virus (DENV) infections, transmission is thought to occur at fine spatiotemporal scales by horizontal transfer of virus between humans and mosquito vectors. To define the dimensions of local transmission and quantify the factors that support it, we examined relationships between infected humans and Aedes aegypti in Thai villages. Methodology/Principal Findings: Geographic cluster investigations of 100-meter radius were conducted around DENV-positive and DENV-negative febrile ‘‘index’’ cases (positive and negative clusters, respectively) from a longitudinal cohort study in rural Thailand. Child contacts and Ae. aegypti from cluster houses were assessed for DENV infection. Spatiotemporal, demographic, and entomological parameters were evaluated. In positive clusters, the DENV infection rate among child contacts was 35.3% in index houses, 29.9% in houses within 20 meters, and decreased with distance from the index house to 6.2% in houses 80–100 meters away (pAe. aegypti were DENV-infectious (i.e., DENV-positive in head/thorax) in positive clusters (23/1755; 1.3%) than negative clusters (1/1548; 0.1%). In positive clusters, 8.2% of mosquitoes were DENV-infectious in index houses, 4.2% in other houses with DENV-infected children, and 0.4% in houses without infected children (pAe. aegypti pupae and adult females were more numerous only in houses containing infectious mosquitoes. Conclusions/Significance: Human and mosquito infections are positively associated at the level of individual houses and neighboring residences. Certain houses with high transmission risk contribute disproportionately to DENV spread to neighboring houses. Small groups of houses with elevated transmission risk are consistent with over-dispersion of transmission (i.e., at a given point in time, people/mosquitoes from a small portion of houses are responsible for the majority of transmission)

A mixed‐methods analysis of younger adults\u27 perceptions of asthma, self‐management, and preventive care: This isn\u27t helping me none

Background: Young adults (ages 18‐44) have increased emergency department use for asthma and poor adherence to medications. The objective of this mixed‐methods study was to understand experiences with and approaches to managing asthma, of which little is known in this age group. Methods: Surveys (Asthma Control Questionnaire, Asthma Quality of Life Questionnaire) and 1:1 semi‐structured interviews were used to explore experiences with asthma, symptoms, self‐management behaviors, and relationship to asthma control and quality of life. Qualitative data were analyzed using content analysis techniques. Descriptive statistics and bivariate correlations were used to examine distributive characteristics and associations between variables. Results: Forty urban adults participated (mean age 32.7 ± 6.2, 1σ). Coughing was reported nearly 46% more often than wheezing, with 42.5% (17/40) coughing until the point of vomiting most days. Most participants delayed using medication for symptoms due to misperceptions about inhalers. Higher symptom frequency and worse asthma control were associated with greater use of non‐pharmacologic symptom management strategies (r=0.645, p\u3c0.001; r=0.360, p=0.022, respectively). Five themes were identified regarding young adults experiences with asthma: (1) having asthma means being limited and missing out on life; (2) healthcare for asthma is burdensome and other things are more important; (3) there is not enough personal benefit in medical interactions to make preventive care worthwhile; (4) there is insufficient support and education about asthma for adults; and (5) people normalize chronic symptoms over time and find ways of coping that fit with their lifestyle. Conclusions & Clinical Relevance: Young adults may tolerate symptoms without using quick‐relief medication or seeking preventive care. Increasing engagement with preventive services will require decreasing perceived burdens and increasing the personal benefits of care. Evaluating for non‐pharmacologic approaches to managing symptoms and asthma‐related coughing may identify uncontrolled asthma. Enhanced training for clinicians in patient‐centric asthma care may be needed

Going Mobile with Primary Care: Smartphone-Telemedicine for Asthma Management in Young Urban Adults (TEAMS)

Background: The majority of adults with persistent asthma have chronically uncontrolled disease and interventions to improve outcomes are needed. We evaluated the efficacy, feasi- bility, and acceptability of a multi-component smartphone-telemedicine program (TEAMS) to deliver asthma care remotely, support provider adherence to asthma management guide- lines, and improve patient outcomes. Methods: TEAMS utilized: (1) remote symptom monitoring, (2) nurse-led smartphone-tele- medicine with self-management training for patients, and (3) Electronic medical record- based clinical decision support software. Adults aged 18-44 (N=33) and primary care providers (N=4) were recruited from a safety-net practice in Upstate New York. Asthma con- trol, quality of life, and FEV1 were measured at 0, 3 and 6 months. Acceptability was assessed via survey and end-of-study interviews. Paired t-test and mixed effects modeling were used to evaluate the effect of the intervention on asthma outcomes. Results: At baseline, 80% of participants had uncontrolled asthma. By 6-months, 80% classi- fied as well-controlled. Improvements in control and quality of life were large (d=1.955, d=1.579). FEV%pred increased 4.2% (d=1.687) with the greatest gain in males, smokers, and lower educational status. Provider adherence to national guidelines increased from 43.3% to 86.7% (CI = 22.11-64.55) and patient adherence to medication increased from 45.58% to 85.29% (CI = 14.79-64.62). Acceptability was 95.7%; In follow up interviews, 29/30 patients and all providers indicated TEAMS worked better than usual care, supported effective self- management, and reduced symptoms over time, which led to greater self-efficacy and motivation to manage asthma. Discussion: Based on these findings, we conclude that smartphone telemedicine could substantially improve clinical asthma management, adherence to guidelines, and patient outcomes

The Canadian Childhood Nephrotic Syndrome (CHILDNEPH) project: Overview of design and methods

Background: Nephrotic syndrome is a commonly acquired kidney disease in children that causes significant morbidity due to recurrent episodes of heavy proteinuria. The management of childhood nephrotic syndrome is known to be highly variable among physicians and care centres. Objectives: The primary objective of the study is to determine centre-, physician-, and patient-level characteristics associated with steroid exposure and length of steroid treatment. We will also determine the association of dose and duration of steroid treatment and time to first relapse as a secondary aim. An embedded qualitative study utilizing focus groups with health care providers will enrich the quantitative results by providing an understanding of the attitudes, beliefs and local contextual factors driving variation in care. Design: Mixed-methods study; prospective observational cohort (quantitative component), with additional semi-structured focus groups of healthcare professionals (qualitative component). Setting: National study, comprised of all 13 Canadian pediatric nephrology clinics. Patients: 400 patients under 18 years of age to be recruited over 2.5 years. Measurements: Steroid doses for all episodes (first presentation, first and subsequent relapses) tracked over course of the study. Physician and centre-level characteristics catalogued, with reasons for treatment preferences documented during focus groups. Methods: All patients tracked prospectively over the course of the study, with data comprising a prospective registry. One focus group at each site to enrich understanding of variation in care. Limitations: Contamination of treatment protocols between physicians may occur as a result of concurrent focus groups. Conclusions: Quantitative and qualitative results will be integrated at end of study and will collectively inform strategies for the development and implementation of standardized evidence-based protocols across centres

Development of a standard of care for patients with valosin-containing protein associated multisystem proteinopathy

Valosin-containing protein (VCP) associated multisystem proteinopathy (MSP) is a rare inherited disorder that may result in multisystem involvement of varying phenotypes including inclusion body myopathy, Paget’s disease of bone (PDB), frontotemporal dementia (FTD), parkinsonism, and amyotrophic lateral sclerosis (ALS), among others. An international multidisciplinary consortium of 40+ experts in neuromuscular disease, dementia, movement disorders, psychology, cardiology, pulmonology, physical therapy, occupational therapy, speech and language pathology, nutrition, genetics, integrative medicine, and endocrinology were convened by the patient advocacy organization, Cure VCP Disease, in December 2020 to develop a standard of care for this heterogeneous and under-diagnosed disease. To achieve this goal, working groups collaborated to generate expert consensus recommendations in 10 key areas: genetic diagnosis, myopathy, FTD, PDB, ALS, Charcot Marie Tooth disease (CMT), parkinsonism, cardiomyopathy, pulmonology, supportive therapies, nutrition and supplements, and mental health. In April 2021, facilitated discussion of each working group’s conclusions with consensus building techniques enabled final agreement on the proposed standard of care for VCP patients. Timely referral to a specialty neuromuscular center is recommended to aid in efficient diagnosis of VCP MSP via single-gene testing in the case of a known familial VCP variant, or multi-gene panel sequencing in undifferentiated cases. Additionally, regular and ongoing multidisciplinary team follow up is essential for proactive screening and management of secondary complications. The goal of our consortium is to raise awareness of VCP MSP, expedite the time to accurate diagnosis, define gaps and inequities in patient care, initiate appropriate pharmacotherapies and supportive therapies for optimal management, and elevate the recommended best practices guidelines for multidisciplinary care internationally. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13023-022-02172-5