A Brief Survey on Intelligent Swarm-Based Algorithms for Solving Optimization Problems

This chapter presents an overview of optimization techniques followed by a brief survey on several swarm-based natural inspired algorithms which were introduced in the last decade. These techniques were inspired by the natural processes of plants, foraging behaviors of insects and social behaviors of animals. These swam intelligent methods have been tested on various standard benchmark problems and are capable in solving a wide range of optimization issues including stochastic, robust and dynamic problems

Does use of pooled cohort risk score overestimate the use of statin?: a retrospective cohort study in a primary care setting

BACKGROUND: Initiation of statin therapy as primary prevention particularly in those with mildly elevated cardiovascular disease risk factors is still being debated. The 2013 ACC/AHA blood cholesterol guideline recommends initiation of statin by estimating the 10-year atherosclerotic cardiovascular disease (ASCVD) risk using the new pooled cohort risk score. This paper examines the use of the pooled cohort risk score and compares it to actual use of statins in daily clinical practice in a primary care setting. METHODS: We examined the use of statins in a randomly selected sample of patients in a primary care clinic. The demographic data and cardiovascular risk parameters were captured from patient records in 1998. The pooled cohort risk score was calculated based on the parameters in 1998. The use of statins in 1998 and 2007, a 10-year interval, was recorded. RESULTS: A total of 847 patients were entered into the analysis. Mean age of the patients was 57.2 ± 8.4 years and 33.1% were male. The use of statins in 1998 was only 10.2% (n = 86) as compared to 67.5% (n = 572) in 2007. For patients with LDL 70-189 mg/dl and estimated 10-year ASCVD risk ≥7.5% (n = 190), 60% (n = 114) of patients were on statin therapy by 2007. There were 124 patients in whom statin therapy was not recommended according to ACC/AHA guideline but were actually receiving statin therapy. CONCLUSIONS: An extra 40% of patients need to be treated with statin if the 2013 ACC/AHA blood cholesterol guideline is used. However the absolute number of patients who needed to be treated based on the ACC/AHA guideline is lower than the number of patients actually receiving it in a daily clinical practice. The pooled cohort risk score does not increase the absolute number of patients who are actually treated with statins. However these findings and the use of the pooled cohort risk score need to be validated further

Visit-to-visit SBP variability and cardiovascular disease in amultiethnic primary care setting:10-year retrospective cohort study

Objectives: The current study aims to determine the relationship of long-term visit-to-visit variability of SBP to cardiovascular disease (CVD) in a multiethnic primary care setting. Method: This is a retrospective study of a cohort of 807 hypertensive patients over a period of 10 years. Three-monthly clinic blood pressure readings were used to derive blood pressure variability (BPV), and CVD events were captured from patient records. Results: Mean age at baseline was 57.2 ± 9.8 years with 63.3% being women. The BPV and mean SBP over 10 years were 14.7 ± 3.5 and 142 ± 8 mmHg, respectively. Prevalence of cardiovascular event was 13%. In multivariate logistic regression analysis, BPV was the predictor of CVD events, whereas the mean SBP was not independently associated with cardiovascular events in this population. Those with lower SBP and lower BPV had fewer cardiovascular events than those with the same low mean SBP but higher BPV (10.5 versus 12.8%). Similarly those with higher mean SBP but lower BPV also had fewer cardiovascular events than those with the same high mean and higher BPV (11.6 versus 16.7%). Other variables like being men, diabetes and Indian compared with Chinese are more likely to be associated with cardiovascular events. Conclusion: BPV is associated with an increase in CVD events even in those who have achieved lower mean SBP. Thus, we should prioritize not only control of SBP levels but also BPV to reduce CVD events further

Acute necrotising pancreatitis and acalculous cholecystitis: a rare presentation of leptospirosis

Leptospirosis typically presents with fever and thrombocytopenia, with or without jaundice. Acute necrotising pancreatitis and acalculous cholecystitis are rare presentations of this spirochetal infection. Here is the case of necrotising pancreatitis and acalculous cholecystitis associated with leptospirosis in an elderly patient. Leptospirosis was diagnosed by serological tests and abdominal CT imaging. The patient was successfully treated medically with intravenous antibiotics (imipenem and ceftriaxone) and proper hydration

Number of blood pressure measurements needed to estimate long-term visit-to-visit systolic blood pressure variability for predicting cardiovascular risk: a 10-year retrospective cohort study in a primary care clinic in Malaysia

Objective: To determine the reproducibility of visit-to-visit blood pressure variability (BPV) in clinical practice. We also determined the minimum number of blood pressure (BP) measurements needed to estimate long-term visit-to-visit BPV for predicting 10-year cardiovascular (CV) risk. Design: Retrospective study Setting: A primary care clinic in a university hospital in Malaysia. Participants: Random sampling of 1403 patients aged 30 years and above without any CV event at baseline. Outcomes measures: The effect of the number of BP measurement for calculation of long-term visit-to-visit BPV in predicting 10-year CV risk. CV events were defined as fatal and non-fatal coronary heart disease, fatal and non-fatal stroke, heart failure and peripheral vascular disease. Results: The mean 10-year SD of systolic blood pressure (SBP) for this cohort was 13.8±3.5 mm Hg. The intraclass correlation coefficient (ICC) for the SD of SBP based on the first eight and second eight measurements was 0.38 (p<0.001). In a primary care setting, visit-to-visit BPV (SD of SBP calculated from 20 BP measurements) was significantly associated with CV events (adjusted OR 1.07, 95% CI 1.02 to 1.13, p=0.009). Using SD of SBP from 20 measurement as reference, SD of SBP from 6 measurements (median time 1.75 years) has high reliability (ICC 0.74, p<0.001), with a mean difference of 0.6 mm Hg. Hence, a minimum of six BP measurements is needed for reliably estimating intraindividual BPV for CV outcome prediction. Conclusion: Long-term visit-to-visit BPV is reproducible in clinical practice. We suggest a minimum of six BP measurements for calculation of intraindividual visit-to-visit BPV. The number and duration of BP readings to derive BPV should be taken into consideration in predicting long-term CV risk

Human evacuation movement simulation model: Concepts and techniques

An emergency scenario is an unforeseen situation that threatens human life, and it is related to the emergent movements of evacuees, which is a critical challenge to model as their movements are unpredictable However, such practices provide less concern on how humans move, individual behaviours and individual differences, obstacles and other components. Therefore, modelling and simulation (M&S) are one of the methods that can be used to face this issue. Modelling is a method of solving problems that can be replaced by a simple object that describes the real system with its behaviour. A program with a running algorithm of a computer model is called a computer simulation. In order to develop a simulation model, a conceptual model consisting of a few components such as input, output, and techniques to be used is found to be important to be investigated for modelling the human evacuation egress (EE) movements. Therefore, two simulation techniques were found appropriate for modelling human EE, namely Social Force (SF) and Agent-based (AB). AB is autonomous with self-directed agents that pursue a series of predefined guidelines and rules to accomplish the objectives whilst the interaction among agents and the environment. whereas SF is an approach to representing human behaviour with social-psychological and physical forces. The primary aim of this work is to review previous conceptual models and to propose a preliminary concept for modelling the human EE simulation. The findings reveal that the significant important components, such as the concept of the EE simulation model, have been identified based on the appropriateness and importance of each, such as the simulation techniques, EE movement procedure, and EE movement state. The conceptual model will be designed to assist in the development process of the EE simulation model for future work

Metaheuristic techniques for conformational search

The drawback in conformational search (CS) is in locating the most stable conformation of a molecule with the minimum potential energy based on a mathematical function. The number of local minima grows exponentially with molecular size and this makes it that more difficult to arrive at a solution. It had been confirmed that CS belongs to the category of NP-hard (non-deterministic polynomial time) problem. Such complexity requires an equally long amount of time to achieve resolution. This phenomenon is thus known as the 'combinatorial explosion'. Metaheuristic techniques have been constantly used in solving CS problems. These population-based probabilistic techniques explore conformational space by random perturbation of atomic Cartesian coordinates or the torsion angles of rotatable bonds. These methods focus on exploring a search space with maximum efficacy. With one or more solutions in the beginning, metaheuristic method follows with a more iterative approach to optimize the search in promising areas away from local solutions. This method is often employed in circumstances where the exact solution methods are unfeasible within a limited time frame. As such, this paper presents various past metaheuristics approaches that have been brought forth in regards to the problem of an effective exploration of the conformational states of molecular systems. Each metaheuristic method is accompanied by its advantages and disadvantages. The concepts of each approach will be explained and their respective applications are discussed

Acute bilateral sensorineural hearing loss: an unexpected and early presentation of acute stroke

We report a case of acute ischemic stroke presented as acute bilateral sensorineural hearing loss. 47 year-old man presented with bilateral hearing loss for one day. Pure tone audiometry revealed moderate bilateral sensorineural hearing loss. Magnetic resonance imaging and magnetic resonance angiogram (MRA) revealed left vertebral artery thrombosis with partial thrombosis of the basilar artery

Crossover and mutation operators of genetic algorithms

Genetic algorithms (GA) are stimulated by population genetics and evolution at the population level where crossover and mutation comes from random variables. The problems of slow and premature convergence to suboptimal solution remain an existing struggle that GA is facing. Due to lower diversity in a population, it becomes challenging to locally exploit the solutions. In order to resolve these issues, the focus is now on reaching equilibrium between the explorative and exploitative features of GA. Therefore, the search process can be prompted to produce suitable GA solutions. This paper begins with an introduction, Section 2 describes the GA exploration and exploitation strategies to locate the optimum solutions. Section 3 and 4 present the lists of some prevalent mutation and crossover operators. This paper concludes that the key issue in developing a GA is to deliver a balance between explorative and exploitative features that complies with the combination of operators in order to produce exceptional performance as a GA as a whole

Validation of the framingham general cardiovascular risk score in a multi-ethnic Asian population a retrospective cohort study

Objective This study aims to examine the validity of the Framingham general cardiovascular disease (CVD) risk chart in a primary care setting. Design This is a 10-year retrospective cohort study. Setting A primary care clinic in a teaching hospital in Malaysia. Participants 967 patients’ records were randomly selected from patients who were attending follow-up in the clinic. Main outcome measures Baseline demographic data, history of diabetes and smoking, blood pressure (BP), and serum lipids were captured from patient records in 1998. Each patient's Framingham CVD score was computed from these parameters. All atherosclerotic CVD events occurring between 1998 and 2007 were counted. Results In 1998, mean age was 57 years with 33.8% men, 6.1% smokers, 43.3% diabetics and 59.7% hypertensive. Median BP was 140/80 mm Hg and total cholesterol 6.0 mmol/L (1.3). The predicted median Framingham general CVD risk score for the study population was 21.5% (IQR 1.2–30.0) while the actual CVD events that occurred in the 10 years was 13.1% (127/967). The median CVD points for men was 30.0, giving them a CVD risk of more than 30%; for women it is 18.5, a CVD risk of 21.5%. Our study found that the Framingham general CVD risk score to have moderate discrimination with an area under the receiver operating characteristic curve (AUC) of 0.63. It also discriminates well for Malay (AUC 0.65, p=0.01), Chinese (AUC 0.60, p=0.03), and Indians (AUC 0.65, p=0.001). There was good calibration with Hosmer-Lemeshow test χ2=3.25, p=0.78. Conclusions Taking into account that this cohort of patients were already on treatment, the Framingham General CVD Risk Prediction Score predicts fairly accurately for men and overestimates somewhat for women. In the absence of local risk prediction charts, the Framingham general CVD risk prediction chart is a reasonable alternative for use in a multiethnic group in a primary care setting