Utility-based Perturbed Gradient Descent: An Optimizer for Continual Learning

Modern representation learning methods often struggle to adapt quickly under non-stationarity because they suffer from catastrophic forgetting and decaying plasticity. Such problems prevent learners from fast adaptation since they may forget useful features or have difficulty learning new ones. Hence, these methods are rendered ineffective for continual learning. This paper proposes Utility-based Perturbed Gradient Descent (UPGD), an online learning algorithm well-suited for continual learning agents. UPGD protects useful weights or features from forgetting and perturbs less useful ones based on their utilities. Our empirical results show that UPGD helps reduce forgetting and maintain plasticity, enabling modern representation learning methods to work effectively in continual learning

Subclinical hypothyroidism ups the risk of vascular complications in type 2 diabetes

The incidence of thyroid dysfunction in diabetic patients is higher than that of the general population. Undiagnosed thyroid dysfunction may affect the metabolic control and enhance cardiovascular, and other chronic complication risks in diabetic patients. Few studies have examined the relationship between subclinical hypothyroidism (SCH) and vascular complications of type 2 diabetes.Objectives: To find out the relationship between SCH and vascular complications in patients with Type 2 diabetes. Subjects andMethods: Our cross sectional study included 110 patients with type 2 DM (45 males and 65 females) who were followed at the Diabetes outpatient Clinics in the state of Kuwait during 6 months period. All patients subjected to complete clinical and laboratory data, including thyroid function tests, total cholesterol (TC), triglyceride (TG), HDL-C, LDL-C, urinary albumin, fundus examination, ECG, and Glycosylated hemoglobin.Results: Among 110 patients, 21 (19.1%) Patients had SCH. Patients with SCHwere more significantly older, with longer duration of diabetes, higher HbA1c, total cholesterol and LDL-C than euthyroid group. However, gender (p = 0.076), BMI (p = 0.092), and smoking (P = 0.715) were not significantly different between the SCH and euthyroid groups. The SCH group had a higher prevalence of dyslipidemia (p = 0.017), diabetic nephropathy (p = 0.003) diabetic retinopathy (p = 0.004) and IHD (p = 0.011) than the euthyroid group while no significant difference in the prevalence of diabetic neuropathy (p = 0.420).Conclusions: SCH is a common endocrine disorder in patients with Type 2 diabetes. It could be associated with a higher prevalence of vascular complications in type 2 diabetes. We could not prove a relation between SCH and diabetic neuropathy.Keywords: Subclinical hypothyroidism, Diabetes, Vascular complicatio

Keeping the mitral smile: is it durable? A comparative study of mid-term outcomes of mitral valve repair and mechanical mitral valve replacement in rheumatic heart patients

Background: Rheumatic heart disease is a significant cause of morbidity and mortality in endemic countries. Traditionally, mechanical valve replacement has been the preferred surgical approach for treating rheumatic mitral valve disease due to its favorable short-term outcomes and low incidence of postoperative complications. However, its midterm results are suboptimal due to increased risks of thrombosis and bleeding. This study compared the midterm outcomes of mitral valve surgeries, repair versus replacement, in rheumatic patients. Methods: A comparative retrospective clinical study was conducted from January 2016 to December 2018. The study included 203 patients who underwent mitral valve surgery for rheumatic heart disease. The patients were divided into two groups: Group A (n=107) had mitral valve repair, and Group B (n=96) had mitral valve replacement. Results: In Group A, the mean age was 45.5 ± 5.2 years, and 49% of the patients were male. While in Group B, the mean age was 46.2 ± 5.35 years, and 54.75% of the patients were males. The two groups had no significant difference regarding cardiac dimensions or function preoperatively. In Group A, the mean cardiopulmonary bypass time was 89 ± 9 minutes, and the mean cross-clamp time was 81 ± 7 minutes; in Group B, the mean cardiopulmonary bypass time was 77±12 min, and the mean cross-clamp time was 81 ± 7 min. The two groups had highly significant differences concerning cardiopulmonary bypass and cross-clamp times (p<0.001). Survival at 5 years was 98.5% for Group A vs. 93.15% for Group B (0.09). The reoperation rate was 9.0% in Group A vs. 4% in Group B (p= 0.261). The thromboembolism incidence was 0.47% in Group A vs. 7.3% in Group B (p= 0.03), and the bleeding-related complications were 0.94% in Group A vs. 7.3% in Group B (p= 0.03). Conclusion: The outcomes of mitral valve repair could be comparable to replacement in patients with rheumatic heart disease. Mitral valve replacement were associated with higher bleeding and thromboembolic complications compared to mitral valve repair

The impacts of substance abuse and dependence on neuropsychological functions in a sample of patients from Saudi Arabia

<p>Abstract</p> <p>Background</p> <p>A lot of studies were directed to explore the relation between drug abuse and neuropsychological functions. Some studies reported that even after a long duration of disappearance of withdrawal or intoxication symptoms, many patients have obvious deterioration of cognitive functions. The aim of this study was to explore the relationship between the substance use disorders and the executive functions.</p> <p>Methods</p> <p>Two groups were selected for this study. An experimental group consisted of 154 patients and further subdivided according to the substance used into three different subgroups: opioid, amphetamine and alcohol groups which included 49, 56 and 49 patients respectively. The control group was selected matching the experimental group in the demographic characteristics and included 100 healthy persons. Tools used were: Benton visual retention tests, color trail making test, Stroop colors-word test, symbol digit modalities test, the five dots cognitive flexibility test, and TAM verbal flexibility test. All the data were subjected to statistical analysis</p> <p>Results</p> <p>The study showed that the group of drug-dependent subjects performed significantly worse than the comparison group on all measures Also, there were significant differences among the subgroups as the alcoholic group was much worse followed by the amphetamine then the opioids groups. Patients with longer duration of dependence and multiple hospital readmissions were much worse in comparison to patients with shorter duration of dependence and less readmission.</p> <p>Conclusion</p> <p>The study confirmed that the functions of specific brain regions underlying cognitive control are significantly impaired in patients of drug addiction. This impairment was significantly related to type of substance, duration of use and number of hospitalization and may contribute to most of behavioral disturbances found in addicts and need much attention during tailoring of treatment programs.</p

Femtosecond Pulsed Laser Deposition of Indium on Si (100)

Deposition of indium on Si(100) substrates is performed under ultrahigh vacuum with an amplified Ti:sapphire laser (130 fs) at wavelength of 800 nm and laser fluence of 0.5 J/cm2. Indium films are grown at room temperature and at higher substrate temperatures with a deposition rate of similar to 0.05 ML/pulse. Reflection high-energy electron diffraction (RHEED) is used during the deposition to study the growth dynamics and the surface structure of the grown films. The morphology of the grown films is examined by ex situ atomic force microscopy (AFM). At room temperature indium is found to form epitaxial two-dimensional layers on the Si(100)-(2x1) surface followed by three-dimensional islands. AFM images show different indium island morphologies such as hexagonal and elongated shapes. At substrate temperatures of 400-420 °C, RHEED intensity oscillations are observed during film growth indicating that the indium film grows in the layer-by-layer mode

Pre-harvest fruit drop, bunch weight and fruit quality of ‘Rothana’ and ‘Ghur’ date palm cultivars as affected by some plant growth regulators

Pre-harvest fruit drop is a serious problem of some date palm cultivars. During 2010 and 2011 seasons, the effect of plant growth regulators 2,4-dichlorophenoxyacetic acid (2,4-D) (50 and 100 ppm), naphthalene acetic acid (NAA) (100 and 150 ppm), gibberellic acid (GA3) (100 and 150 ppm) and benzyladenine (BA) (100 and 150 ppm) applications, at 40 and 70 days after pollination, on pre-harvest fruit drop and quality of ‘Rothana’ and ‘Ghur’ dates were studied. In both cultivars, the application of growth regulators at both rates significantly decreased fruit drop. In this respect, 2,4-D and GA3 were the most effective treatments followed by BA, while NAA was the least effective. The reduction in fruit drop resulted in a higher bunch weight in the treated fruit than the control. The high rate of BA was more effective than the low rate in decreasing fruit drop of ‘Ghur’ cultivar. In ‘Rothana’ cultivar, bunch weight was higher than the control with both 2,4-D rates; whereas, with GA3 and BA, only the high rate was effective; while in ‘Ghur’ cultivar, bunch weight of all growth regulators treatments was higher than the control. The rutab percentage was lower in NAA treatments than for all the other treatments, except for control in ‘Ghur’ cultivar. Fruit and flesh weight of ‘Rothana’ cultivar were higher at the high rate of 2,4-D, the low rate of GA3 and BA treatments than in the control. There were no consistent effects for growth regulators on the physical and chemical quality characteristics of fruit, possibly due to the large variations of the fruit load among the treatments. It was concluded that under hot arid conditions, the application of growth regulators of especially 2,4-D (50 ppm) and GA3 (150 ppm) at both 40 and 70 days from pollination is recommended to reduce pre-harvest drop, and improve fruit quality of both ‘Rothana’ and ‘Ghur’ date palm cultivars.Keywords: Date palm, plant growth regulators, yield, quality, fruit drop, Phoenix dactylifera

Evaluating the Effects of Human Activity over the Last Decades on the Soil Organic Carbon Pool Using Satellite Imagery and GIS Techniques in the Nile Delta Area, Egypt

The study aims to clarify the relationship between soil organic carbon (SOC) and human activity under arid conditions, in the east area of the Nile Delta, Egypt. SOC is one of the critical factors in food production and plays an important role in the climate change because it affects the physio-chemical soil characteristics, plant growth, and contributes to sustainable development on global levels. For the purpose of our investigations, 120 soil samples (0–30 cm) were collected throughout different land uses and soil types of the study area. Multiple linear regressions (MLR) were used to investigate the spatiotemporal relationship of SOC, soil characteristics, and environmental factors. Remote sensing data acquired from Landsat 5 TM in July 1995 and operational land imager (OLI) in July 2018 were used to model SOC pool. The results revealed significant variations of soil organic carbon pool (SOCP) among different soil textures and land-uses. Soil with high clay content revealed an increase in the percentage of soil organic carbon, and had mean SOCP of 6.08 ± 1.91 Mg C ha−1, followed by clay loams and loamy soils. The higher values of SOCP were observed in the northern regions of the study area. The phenomenon is associated with the expansion of the human activity of initiating fish ponds that reflected higher values of SOC that were related to the organic additions used as nutrients for fish. Nevertheless, the SOC values decreased in southeast of the study area with the decrease of soil moisture contents and the increase in the heavy texture profiles. As a whole, our findings pointed out that the human factor has had a significant impact on the variation of soil organic carbon values in the Eastern Nile Delta from 1995 to 2018. As land use changes from agricultural activity to fish ponds, the SOCP significantly increased. The agriculture land-use revealed higher SOCP with 60.77 Mg C ha−1 in clay soils followed by fish ponds with 53.43 Mg C ha−1. The results also showed a decrease in SOCP values due to an increasing in land surface temperature (LST) thus highlighting that influence of temperature and ambient soil conditions linked to land-use changes have a marked impact on surface SOCP and C sequestration

The effect of cold crystalloid versus warm blood cardioplegia on the myocardium during coronary artery bypass grafting

Background: The optimal cardioplegic solution is still debated. The objective of this study was to compare the effect of cold crystalloid versus warm blood cardioplegia on the myocardial injury during coronary artery bypass grafting. Methods: The study included 34 consecutive patients who underwent elective primary on-pump isolated coronary artery bypass grafting from 2016 to 2019. We randomly assigned the patients into two groups. Group (ICCC) (n= 17) received intermittent antegrade cold crystalloid cardioplegia and Group (IWBC) (n= 17) received intermittent antegrade warm blood cardioplegia. Results: There was no difference in the preoperative and operative variables between groups. The time taken by the heart to regain normal sinus rhythm was significantly longer in the cold crystalloid group (7.06 ± 1.8 vs. 2.17 ± 0.8 minutes, p&lt;0.001) with a higher rate of reperfusion ventricular arrhythmia (35% versus 6%; p=0.03) compared to the warm blood cardioplegia group. Both coronary sinus acid production and lactate level were significantly higher in the warm blood group than in the cold crystalloid group (p&lt; 0.001 and 0.043, respectively). The ischemic ECG changes and the severity of new segmental wall motion abnormalities were non-significantly different between both groups (p= 0.68 and 0.67, respectively). Postoperative CK-MB and cTnI levels in all-time points were not significantly different between groups (p= 0.46 and 0.37, respectively). ICU (2.29 ± 0.77 vs. 2.41 ± 0.87 days, p= 0.68) and hospital stay (9.28 ± 0.76 vs. 9.42 ± 0.88 days, p= 0.62) were non-significantly different between both groups. Conclusion: Intermittent antegrade cold crystalloid cardioplegia was associated with attenuated myocardial metabolism. However, it was associated with a longer time to regain normal sinus rhythm and more reperfusion ventricular arrhythmias. We did not find differences in the clinical and echocardiographic outcomes and cardiac enzymes between cold crystalloid and warm blood cardioplegia

Factors affecting mental fitness for work in a sample of mentally ill patients

<p>Abstract</p> <p>Background</p> <p>Mental fitness for work is the ability of workers to perform their work without risks for themselves or others. Mental fitness was a neglected area of practice and research. Mental ill health at work seems to be rising as a cause of disablement. Psychiatrists who may have had no experience in relating mental health to working conditions are increasingly being asked to undertake these examinations. This research was done to explore the relationship of mental ill health and fitness to work and to recognize the differences between fit and unfit mentally ill patients.</p> <p>Methods</p> <p>This study was cross sectional one. All cases referred to Al-Amal complex for assessment of mental fitness during a period of 12 months were included. Data collected included demographic and clinical characteristics, characteristics of the work environment and data about performance at work. All data was subjected to statistical analysis.</p> <p>Results</p> <p>Total number of cases was 116, the mean age was 34.5 ± 1.4. Females were 35.3% of cases. The highly educated patients constitute 50.8% of cases. The decision of the committee was fit for regular work for 52.5%, unfit for 19.8% and modified work for 27.7%. The decision was appreciated only by 29.3% of cases. There were significant differences between fit, unfit and modified work groups. The fit group had higher level of education, less duration of illness, and better performance at work. Patients of the modified work group had more physical hazards in work environment and had more work shift and more frequent diagnosis of substance abuse. The unfit group had more duration of illness, more frequent hospitalizations, less productivity, and more diagnosis of schizophrenia.</p> <p>Conclusion</p> <p>There are many factors affecting the mental fitness the most important are the characteristics of work environment and the most serious is the overall safety of patient to self and others. A lot of ethical and legal issues should be kept in mind during such assessment as patient's rights, society's rights, and the laws applied to unfit people.</p