Mapping lessons from ants to free flight: An ant-based weather aviodance algorithm in free flight airspace

The continuing growth of air traffic worldwide motivates the need for new approaches to air traffic management that are more flexible both in terms of traffic volume and weather. Free Flight is one such approach seriously considered by the aviation community. However the benefits of Free Flight are severely curtailed in the convective weather season when weather is highly active, leading aircrafts to deviate from their optimal trajectories. This paper investigates the use of ant colony optimization in generating optimal weather avoidance trajectories in Free Flight airspace. The problem is motivated by the need to take full advantage of the airspace capacity in a Free Flight environment, while maintaining safe separation between aircrafts and hazardous weather. The experiments described herein were run on a high fidelity Free Flight air traffic simulation system which allows for a variety of constraints on the computed routes and accurate measurement of environments dynamics. This permits us to estimate the desired behavior of an aircraft, including avoidance of changing hazardous weather patterns, turn and curvature constraints, and the horizontal separation standard and required time of arrival at a pre determined point, and to analyze the performance of our algorithm in various weather scenarios. The proposed Ant Colony Optimization based weather avoidance algorithm was able to find optimum weather free routes every time if they exist. In case of highly complex scenarios the algorithm comes out with the route which requires the aircraft to fly through the weather cells with least disturbances. All the solutions generated were within flight parameters and upon integration with the flight management system of the aircraft in a Free Flight air traffic simulator, successfully negotiated the bad weather

Effect of replacement therapy on clinical symptoms in patients with vitamin D deficiency

Background: 25(OH) D is an important component for human health. Vitamin D deficiency is a worldwide problem. Previous epidemiological studies have shown the association of this deficiency with development of other chronic disease that also increase the morbidity. So early detection of deficiency helps to plan intervention and treatment to avoid morbidity. Objective: To evaluate the association of vitamin D deficiency in individuals suffering with chronic diseases and the effect of replacement therapy on the clinical symptoms of vitamin D deficiency. Method: This study analyzed a total of 115 patients visiting the Diabetes and Endocrine Research Centre. Factors such as age, gender, duration of sun exposure and body parts exposed to sunshine were studied. The data was recorded on a questionnaire performa. Patients with 25(OH) D levels below 30ng/ml were considered to have insufficient levels. 48 patients who agreed for treatment were given standard loading and maintenance dose of vitamin D. 31 Patients reported back after 3 months of maintenance dose treatment. Results: The mean age of patients was 47.82±13.86 years. Duration of sunshine exposure was significantly low with p-value of 0.005. In our study, 112/115(97.3%) patients were found to have 25(OH) D level below 30ng/ml and 41/115 (21.5%) were severely deficient. 48(41%) patients agreed for replacement therapy. However, only 31 reported back with vitamin D level. In comparison to pretreatment records, there was significant improvement in vitamin D levels after 3 months of treatment. There was improvement with symptoms such as lethargy which improved in 11/17, whereas depression and body aches improved in 12/19 and 16/26 patients respectively. Conclusion: It is important to recognize the deficiency of vitamin D level in patient suffering from chronic diseases in order to avoid other co morbidities. So, this study can help to make policy in future about which population needs to be screened and what preventive precautions can be taken

Evolutionary-Computation Based Risk Assessment of Aircraft Landing Sequencing Algorithms

Abstract. Usually, Evolutionary Computation (EC) is used for optimisation and machine learning tasks. Recently, a novel use of EC has been proposedMultiobjective Evolutionary Based Risk Assessment (MEBRA). MEBRA characterises the problem space associated with good and inferior performance of computational algorithms. Problem instances are represented ("scenario Representation") and evolved ("scenario Generation") in order to evaluate algorithms ("scenario Evaluation"). The objective functions aim at maximising or minimising the success rate of an algorithm. In the "scenario Mining" step, MEBRA identifies the patterns common in problem instances when an algorithm performs best in order to understand when to use it, and in instances when it performs worst in order to understand when not to use it. So far, MEBRA has only been applied to a limited number of problems. Here we demonstrate its viability to efficiently detect hot spots in an algorithm's problem space. In particular, we apply the basic MEBRA rationale in the area of Air Traffic Management (ATM). We examine two widely used algorithms for Aircraft Landing Sequencing: First Come First Served (FCFS) and Constrained Position Shifting (CPS). Through the use of three different problem ("scenario") representations, we identify those patterns in ATM problems that signal instances when CPS performs better than FCFS, and those when it performs worse. We show that scenario representation affects the quality of MEBRA outputs. In particular, we find that the variable-length chromosome representation of aircraft scheduling sequence scenarios converges fast and finds all relevant risk patterns associated with the use of FCFS and CPS

A Study of Electrocardiographic Changes in patients with Newly Diagnosed Primary Hypothyroidism: A Cross-Sectional Study

Background: The thyroid hormones have an important role in the cardiovascular system; even minimal change in its level can cause significant alteration in the cardiac activity which can cause considerable electrocardiographic changes. We conducted this study to assess the electrocardiographic (ECG) changes in patients who were newly diagnosed with primary hypothyroidism. Methods: This study is a descriptive cross-sectional study conducted among 71 newly diagnosed subclinical and overt primary hypothyroidism patients visiting the out-patient department (OPD) of Universal College of Medical Sciences, Nepal from December 2018 to June 2020 after taking ethical clearance from the institutional review committee (UCMS/IRC/212/18). ECG was obtained for each patient at the time of diagnosis of primary hypothyroidism. The data were analyzed with SPSS Version 16. Results: The most common ECG changes were sinus bradycardia seen in 32.4%, followed by T wave inversion in 21.1%, low voltage QRS complex in 15.5%, and prolonged PR interval in 14.1%. ECG changes were seen in 62% of cases of newly diagnosed primary hypothyroidism. Among all patients, subclinical hypothyroidism accounted for 7%, while overt hypothyroidism accounted for 55% of the ECG findings. Conclusion: Our study found ECG changes like sinus bradycardia, T wave inversion, low QRS voltage, and prolonged PR interval in newly diagnosed primary hypothyroidism. We suggest that every newly diagnosed hypothyroid patient should be evaluated for ECG changes

Fuel traps: mapping stability via water association.

Hydrogen storage is a key enabling technology required for attaining a hydrogen-based economy. Fundamental research can reveal the underlying principles controlling hydrogen uptake and release by storage materials, and also aid in characterizing and designing novel storage materials. New ideas for hydrogen storage materials come from exploiting the properties of hydrophobic hydration, which refers to water s ability to stabilize, by its mode of association, specific structures under specific conditions. Although hydrogen was always considered too small to support the formation of solid clathrate hydrate structures, exciting new experiments show that water traps hydrogen molecules at conditions of low temperatures and moderate pressures. Hydrogen release is accomplished by simple warming. While these experiments lend credibility to the idea that water could form an environmentally attractive alternative storage compound for hydrogen fuel, which would advance our nation s goals of attaining a hydrogen-based economy, much work is yet required to understand and realize the full potential of clathrate hydrates for hydrogen storage. Here we undertake theoretical studies of hydrogen in water to establish a firm foundation for predictive work on clathrate hydrate H{sub 2} storage capabilities. Using molecular simulation and statistical mechanical theories based in part on quantum mechanical descriptions of molecular interactions, we characterize the interactions between hydrogen and liquid water in terms of structural and thermodynamic properties. In the process we validate classical force field models of hydrogen in water and discover new features of hydrophobic hydration that impact problems in both energy technology and biology. Finally, we predict hydrogen occupancy in the small and large cages of hydrogen clathrate hydrates, a property unresolved by previous experimental and theoretical work

The prevalence of waterpipe tobacco smoking among the general and specific populations: a systematic review

Abstract Background The objective of this study was to systematically review the medical literature for the prevalence of waterpipe tobacco use among the general and specific populations. Methods We electronically searched MEDLINE, EMBASE, and the ISI the Web of Science. We selected studies using a two-stage duplicate and independent screening process. We included cohort studies and cross sectional studies assessing the prevalence of use of waterpipe in either the general population or a specific population of interest. Two reviewers used a standardized and pilot tested form to collect data from each eligible study using a duplicate and independent screening process. We stratified the data analysis by country and by age group. The study was not restricted to a specific context. Results Of a total of 38 studies, only 4 were national surveys; the rest assessed specific populations. The highest prevalence of current waterpipe smoking was among school students across countries: the United States, especially among Arab Americans (12%-15%) the Arabic Gulf region (9%-16%), Estonia (21%), and Lebanon (25%). Similarly, the prevalence of current waterpipe smoking among university students was high in the Arabic Gulf region (6%), the United Kingdom (8%), the United States (10%), Syria (15%), Lebanon (28%), and Pakistan (33%). The prevalence of current waterpipe smoking among adults was the following: Pakistan (6%), Arabic Gulf region (4%-12%), Australia (11% in Arab speaking adults), Syria (9%-12%), and Lebanon (15%). Group waterpipe smoking was high in Lebanon (5%), and Egypt (11%-15%). In Lebanon, 5%-6% pregnant women reported smoking waterpipe during pregnancy. The studies were all cross-sectional and varied by how they reported waterpipe smoking. Conclusion While very few national surveys have been conducted, the prevalence of waterpipe smoking appears to be alarmingly high among school students and university students in Middle Eastern countries and among groups of Middle Eastern descent in Western countries