Mathematical Modelling of Nano-Electronic Systems

Double-Qdots (DQDs) are attractive in light of their potential application to quantum computing and other electronic applications, e.g. as specialized sensors. We consider the electronic properties of a system consisting of two quantum dots in physical proximity, which we will refer to as the DQD. Our main goal is to derive the essential properties of the DQD from a model that is rigorous yet numerically tractable, and largely circumvents the complexities of an ab initio simulation. To this end we propose a class of novel Hamiltonians that captures the dynamics of a bi-partite quantum system, wherein the interaction is described via a convolution or a Wiener-Hopf type operator. We subsequently describe the density of states function and derive the electronic properties of the underlying system. Our analysis shows that the model captures a plethora of electronic profiles which serves as evidence for the versatility of the proposed framework for DQD channel modelling. A massive body of mathematical physics results, dating mostly to the last half a century, give evidence to the claim that the statistical characteristic of fluctuations in the level structure of a quantum system provides essential information about its dynamic properties, e.g. in some instances these statistical parameters show whether or not the underlying classical dynamics is integrable or chaotic. Following this tradition we have conducted statistical analysis of the data generated numerically from the model at hand. In this way we have characterized the fine-scale fluctuations of the spectra for several choices of the constituents. In conclusion, we have found that the model is versatile enough to produce several statistically distinct types of level structure. In particular, the model is capable of reproducing very complex level structures, such as those of the resonant microwave cavities that have been obtained experimentally in the 1990

Feasibility and Reliability of SmartWatch to Obtain 3-Lead Electrocardiogram Recordings

Some of the recently released smartwatch products feature a single-lead electrocardiogram (ECG) recording capability. The reliability of obtaining 3-lead ECG with smartwatches is yet to be confirmed in a large study. This study aimed to assess the feasibility and reliability of smartwatch to obtain 3-lead ECG recordings, the classical Einthoven ECG leads I-III compared to standard ECG. To record lead I, the watch was worn on the left wrist and the right index finger was placed on the digital crown for 30 s. For lead II, the watch was placed on the lower abdomen and the right index finger was placed on the digital crown for 30 s. For lead III, the same process was repeated with the left index finger. Spearman correlation and Bland-Altman tests were used for data analysis. A total of 300 smartwatch ECG tracings were successfully obtained. ECG waves’ characteristics of all three leads obtained from the smartwatch had a similar duration, amplitude, and polarity compared to standard ECG. The results of this study suggested that the examined smartwatch (Apple Watch Series 4) could obtain 3-lead ECG tracings, including Einthoven leads I, II, and III by placing the smartwatch on the described positions

Medication Gaps and Antipsychotic Polypharmacy in Previously Hospitalized Schizophrenia Patients: An Electronic Cohort Study in Three Canadian Provinces

Background: Real world evidence about antipsychotics focuses on rehospitalization. Modeling the time course of pharmacotherapy would show patients\u27 adherence to medications and physicians\u27 adherence to medication guidelines. We aimed to calculate the cumulative time spent in second generation antipsychotics (SGAs), gaps, antipsychotic polypharmacy, and clozapine in discharged schizophrenia patients. Methods: Hospitalization and pharmacy dispensing data from 2008–2018 in Manitoba, Saskatchewan, and British Columbia were linked and an electronic cohort (N = 2,997) was created (mean follow-up: 49 months, SD = 38). Cohort members were required to have a minimum of 6 weeks medicated with aripiprazole, olanzapine, paliperidone, quetiapine, risperidone, or ziprasidone. Results: The multistate model predicted that schizophrenia patients accumulated 44 months in SGA monotherapy, 4 months in polypharmacy, 11 months in medication gaps and 17 days in clozapine over a 5-year period. The majority of transitions were between SGA and medication gap. Accumulated time in medication gaps was seven times as much as in clozapine. Each 10% delay in SGA initiation post-discharge was associated with a 2, 1, and 6% higher risk for polypharmacy (95% CI: 1.01–1.02), gap (95% CI: 1.01–1.01), and clozapine (95% CI: 1.04–1.08), respectively. Interpretation: Schizophrenia patients accumulated more time unmedicated and in polypharmacy compared to clozapine. Either treatment guidelines for schizophrenia are not followed, or real-world challenges hamper their implementation

Atrial fibrillation: A review of modifiable risk factors and preventive strategies

Atrial fibrillation (AF), as the most common cardiac arrhythmia worldwide, is associated with increased mortality and morbidity. Successful therapeutic strategies have been introduced so far, but they are associated with significant costs. Therefore, identification of modifiable risk factors of AF and the development of appropriate preventive strategies may play a substantial role in promoting community health and reducing health care system costs. Modifiable cardiovascular risk factors including obesity, hypertension, diabetes mellitus, obstructive sleep apnea, alcohol consumption, smoking, and sedentary lifestyles have been proposed as possible contributors to the development and progression of AF. In this review, we discuss the role of modifiable risk factors in the development and management of AF and the evidence for the underlying mechanism for each of the potential risk factor

Sleep Disorders and Atrial Fibrillation: Current Situation and Future Directions

Atrial fibrillation (AF) is a growing health problem worldwide. In recent years, there has been a rising interest in the relationship between sleep disorders and AF. Several studies have reported higher prevalence and incidence rates of AF in patients with obstructive sleep apnea-hypopnea syndrome (OSAHS). However, some believe that OSAHS is not a risk factor for AF; but AF, by itself, is regarded as one of the possible triggers for OSAHS. In this study, the related literature investigating the association between OSAHS and AF was reviewed, and then the possible mechanisms of this interplay were discussed. To conclude, recommendations for further research in this field were presented to researchers and some points were highlighted for physicians.[GMJ.2018;7:e1416]</jats:p

Exercise and Atrial Fibrillation: Some Good News and Some Bad News

Atrial fibrillation (AF) is considered as the most common sustained arrhythmia in adults, whose incidence rate is on the rise due to the increase in the mean age of the global population. In recent years, many efforts have been made to identify effective factors in the incidence of AF to prevent them and thereby reduce the consequences of AF. Physical activity is one of the topics that attracted much attention in the last two decades. According to some findings, extreme and prolonged exercise itself can be considered as a risk factor for the onset of AF; however, other studies have shown that exercise can be regarded a protective factor against AF in the general population. The present study reviews the findings of studies on the relationship between AF and exercise and discusses possible mechanisms for this relationship. Additionally, we present some recommendations for researchers and physicians about exercise management in association with AF prevention. [GMJ.2018;7:e1401] </jats:p

Consumption Patterns of Grain-Based Foods among Children and Adolescents in Canada: Evidence from Canadian Community Health Survey-Nutrition 2015

The current analyses used data from the Canadian Community Health Survey-Nutrition 2015 to investigate grain-based food (GBF) dietary patterns of consumptions among 6,400,000 Canadian children and adolescents 2 to 18 years old. Nutrient intakes, socioeconomic differences, body mass index (BMI) z-scores, and intakes of several food groups were examined across the identified grain patterns of consumption. We employed k-mean cluster analysis to identify the consumption patterns of grain products. Based on the contributions of 21 grain food groups to the total energy intake of each individual, seven GBF consumption patterns were identified including other bread; salty snacks; pasta; rice; cakes and cookies; white bread; and mixed grains. Individuals having less than one serving of grain products were also separately categorized as no-grain consumers. Mean energy intake (kcal/day) was lowest for the “no-grain” consumers and greatest in children/adolescents consuming a “salty snacks” pattern when all GBF patterns were compared. Children and adolescents with “no-grain” and “rice” GBF consumption patterns had significantly lower intakes of several nutrients including dietary fiber, folate, magnesium, calcium, iron, zinc, thiamin, niacin, and riboflavin. No associations were observed with any of the identified GBF patterns and BMI z-scores. In addition, the socioeconomic status (SES) indicators such as household incomes and immigration status of participants were shown to be significantly different across the identified clusters.</jats:p