Optimal-Dimensionality Sampling on the Sphere: Improvements and Variations

For the accurate representation and reconstruction of band-limited signals on the sphere, an optimal-dimensionality sampling scheme has been recently proposed which requires the optimal number of samples equal to the number of degrees of freedom of the signal in the spectral (harmonic) domain. The computation of the spherical harmonic transform (SHT) associated with the optimal-dimensionality sampling requires the inversion of a series of linear systems in an iterative manner. The stability of the inversion depends on the placement of iso-latitude rings of samples along co-latitude. In this work, we have developed a method to place these iso-latitude rings of samples with the objective of improving the well-conditioning of the linear systems involved in the computation of the SHT. We also propose a multi-pass SHT algorithm to iteratively improve the accuracy of the SHT of band-limited signals. Furthermore, we review the changes in the computational complexity and improvement in accuracy of the SHT with the embedding of the proposed methods. Through numerical experiments, we illustrate that the proposed variations and improvements in the SHT algorithm corresponding to the optimal-dimensionality sampling scheme significantly enhance the accuracy of the SHT.Comment: 5 Pages, 4 figure

Ventricular fibrillation with intracoronary adenosine during fractional flow reserve assessment.

Fractional flow reserve (FFR) measurement provides useful hemodynamic assessment of intermediate coronary stenoses affecting long term outcomes. While the gold standard remains intravenous adenosine, intracoronary (IC) bolus administration of adenosine is routinely used in clinical practice because of its ease of use and lower dose providing comparative hyperemia with the most common side effect being a transient atrioventricular block. A 62year old male underwent left heart catheterization after ruling in for non-ST elevation myocardial infarction (NSTEMI). Presenting electrocardiogram (ECG) showed an old left bundle branch block and T-wave inversions in lateral leads (QTc 494ms) with no significant electrolyte abnormalities. Coronary angiography revealed an intermediate lesion in mid left anterior descending coronary artery. FFR assessment with IC adenosine (24μg/mL of normal saline) was performed inducing ventricular fibrillation (VF). He was successfully defibrillated with a single 200J shock and no further arrhythmias were noticed during rest of his hospital stay

Impact of COVID-19 on Ophthalmologists

Objectives: To determine the effects of COVID 19 pandemic on the professional lives of ophthalmologists Methods: This cross sectional survey was conducted for 6 months in late 2020 and used google forms for data collection. Results: Total 68 respondents gave their likert response for each of the 20 statements. No. %, median, mode and interquartile range, of all respondents likert sentiment for each statement, were calculated. Survey results showed general, ‘consent and consensus’. Conclusion: Covid-19 has influenced professional lives of ophthalmologists

Interventions for Adolescent Mental Health: An Overview of Systematic Reviews.

Many mental health disorders emerge in late childhood and early adolescence and contribute to the burden of these disorders among young people and later in life. We systematically reviewed literature published up to December 2015 to identify systematic reviews on mental health interventions in adolescent population. A total of 38 systematic reviews were included. We classified the included reviews into the following categories for reporting the findings: school-based interventions (n = 12); community-based interventions (n = 6); digital platforms (n = 8); and individual-/family-based interventions (n = 12). Evidence from school-based interventions suggests that targeted group-based interventions and cognitive behavioral therapy are effective in reducing depressive symptoms (standard mean difference [SMD]: -.16; 95% confidence interval [CI]: -.26 to -.05) and anxiety (SMD: -.33; 95% CI: -.59 to -.06). School-based suicide prevention programs suggest that classroom-based didactic and experiential programs increase short-term knowledge of suicide (SMD: 1.51; 95% CI: .57-2.45) and knowledge of suicide prevention (SMD: .72; 95% CI: .36-1.07) with no evidence of an effect on suicide-related attitudes or behaviors. Community-based creative activities have some positive effect on behavioral changes, self-confidence, self-esteem, levels of knowledge, and physical activity. Evidence from digital platforms supports Internet-based prevention and treatment programs for anxiety and depression; however, more extensive and rigorous research is warranted to further establish the conditions. Among individual- and family-based interventions, interventions focusing on eating attitudes and behaviors show no impact on body mass index (SMD: -.10; 95% CI: -.45 to .25); Eating Attitude Test (SMD: .01; 95% CI: -.13 to .15); and bulimia (SMD: -.03; 95% CI: -.16 to .10). Exercise is found to be effective in improving self-esteem (SMD: .49; 95% CI: .16-.81) and reducing depression score (SMD: -.66; 95% CI: -1.25 to -.08) with no impact on anxiety scores. Cognitive behavioral therapy compared to waitlist is effective in reducing remission (odds ratio: 7.85; 95% CI: 5.31-11.6). Psychological therapy when compared to antidepressants have comparable effect on remission, dropouts, and depression symptoms. The studies evaluating mental health interventions among adolescents were reported to be very heterogeneous, statistically, in their populations, interventions, and outcomes; hence, meta-analysis could not be conducted in most of the included reviews. Future trials should also focus on standardized interventions and outcomes for synthesizing the exiting body of knowledge. There is a need to report differential effects for gender, age groups, socioeconomic status, and geographic settings since the impact of mental health interventions might vary according to various contextual factors

Perceptions about the cause of schizophrenia and the subsequent help seeking behavior in a Pakistani population – results of a cross-sectional survey

<p>Abstract</p> <p>Background</p> <p>There is a cultural variability around the perception of what causes the syndrome of schizophrenia. Generally patients with schizophrenia are considered dangerous. They are isolated and treatment is delayed. Studies have shown favorable prognosis with good family and social support, early diagnosis and management. Duration of untreated psychosis is a bad prognostic indicator. We aimed to determine the perceptions regarding the etiology of schizophrenia and the subsequent help seeking behavior.</p> <p>Methods</p> <p>This cross-sectional study was carried out on a sample of 404 people at the out patient departments of Aga Khan University Hospital Karachi. Data was collected via a self-administered questionnaire. Questions were related to a vignette of a young man displaying schizophrenic behavior. Data was analyzed on SPSS v 14.</p> <p>Results</p> <p>The mean age of the participants was 31.4 years (range = 18–72) and 77% of them were males. The majorities were graduates (61.9%) and employed (50%). Only 30% of the participants attributed 'mental illness' as the main cause of psychotic symptoms while a large number thought of 'God's will' (32.3%), 'superstitious ideas' (33.1%), 'loneliness' (24.8%) and 'unemployment' (19.3%) as the main cause. Mental illness as the single most important cause was reported by only 22%. As far as management is concerned, only 40% reported psychiatric consultation to be the single most important management step. Other responses included spiritual healing (19.5%) and Sociachanges (10.6) while 14.8% of respondents said that they would do nothing. Gender, age, family system and education level were significantly associated with the beliefs about the cause of schizophrenia (p < 0.05). While these variables plus 'religious inclination' and 'beliefs about cause' were significantly associated with the help seeking behavior of the participants.</p> <p>Conclusion</p> <p>Despite majority of the study population being well educated, only a few recognized schizophrenia as a mental illness and many held superstitious beliefs. A vast majority of Pakistanis have non-biomedical beliefs about the cause of schizophrenia. Their help seeking behavior in this regard is inappropriate and detrimental to the health of schizophrenic patients. Areas for future research have been identified.</p

Recurrent takotsubo cardiomyopathy in the setting of transient neurological symptoms: a case report

<p>Abstract</p> <p>Introduction</p> <p>First described in Japan, takotsubo cardiomyopathy is increasingly becoming recognized worldwide as a cause of sudden and reversible diminished left ventricular function characterized by left apical ballooning and hyperkinesis of the basal segments, often with symptoms mimicking a myocardial infarction. Associated with physical or emotional stress, its exact pathogenesis has not been established, though evidence supports a neurohumoral etiology. Additionally, recurrence of this condition is rare. In this report, we present a rare case of recurrent takotsubo cardiomyopathy in a post-menopausal woman who presented with transient neurological complaints on both occasions.</p> <p>Case presentation</p> <p>We present a rare case of a 76-year-old Caucasian woman with no history of congestive heart failure who presented to our emergency department twice with transient neurological complaints. On the first occasion, she was found to have transient aphasia which resolved within 24 hours, yet during that period she also developed symptoms of congestive heart failure and was noted to have a new, significantly depressed ejection fraction with apical akinesis and possible apical thrombus. One month after her presentation a repeat echocardiogram revealed complete resolution of all wall motion abnormalities and a return to baseline status. Seven months later she presented with ataxia, was diagnosed with vertebrobasilar insufficiency, and again developed symptoms and echocardiography findings similar to those of her first presentation. Once again, at her one-month follow-up examination, all wall motion abnormalities had completely resolved and her ejection fraction had returned to normal.</p> <p>Conclusion</p> <p>Though the exact etiology of takotsubo cardiomyopathy is unclear, a neurohumoral mechanism has been proposed. Recurrence of this disorder is rare, though it has been reported in patients with structural brain abnormalities. This report is the first to describe recurrent takotsubo cardiomyopathy in a patient with transient neurological symptoms. In our patient, as expected in patients with this condition, complete resolution of all left ventricular abnormalities occurred within a short period of time. It is important for clinicians to be aware of this increasingly recognized syndrome, including its association with recurrence, especially in the clinical setting of neurologic dysfunction.</p

Age-induced aortic modifications are accompanied by alterations in the antioxidant defense system in female rats

IntroductionAging leads to significant structural and functional changes in blood vessels, which disrupt their normal function and impact cardiovascular health. Current research is actively exploring the NRF2 antioxidative pathway, recognizing its role in protecting cells by preserving their antioxidant defenses against damage. However, there has been limited exploration into the role of the NRF2 pathway in vascular aging. The primary objective of this study was to determine whether age-related changes in the aorta are associated with variations in the baseline levels of antioxidant enzymes, with a particular emphasis on how the NRF2 pathway operates in the aortic wall.MethodsA group of healthy aging female SD rats was compared with their younger counterparts. Various assessments were conducted, including measuring blood pressure, analyzing serum lipid profiles, examining aortic tissue, and assessing the expression of antioxidant enzymes.ResultsThe results revealed significant differences in both blood pressure and serum lipid levels between the aged and younger rats. The examination of the aorta in older rats showed structural alterations, increased apoptosis, and the accumulation of fatty deposits. In the older rats, levels of SOD-1 (superoxide dismutase) and GSS (glutathione synthetase) were lower, whereas NRF2, KEAP-1 (Kelch-like ECH-associated protein 1), and HO-1 (Heme oxygenase 1) were higher.DiscussionThis study advances our understanding of how aging affects the antioxidant system in blood vessels, particularly in relation to the regulation of the NRF2/HO-1 pathway in the aorta. These findings suggest that targeting the NRF2/HO-1 pathway could present anovel therapeutic approach for addressing age-related vascular issues