Application of the artificial bee colony algorithm for solving the set covering problem.

The set covering problem is a formal model for many practical optimization problems. In the set covering problem the goal is to choose a subset of the columns of minimal cost that covers every row. Here, we present a novel application of the artificial bee colony algorithm to solve the non-unicost set covering problem. The artificial bee colony algorithm is a recent swarm metaheuristic technique based on the intelligent foraging behavior of honey bees. Experimental results show that our artificial bee colony algorithm is competitive in terms of solution quality with other recent metaheuristic approaches for the set covering problem.

A prefiltered cuckoo search algorithm with geometric operators for solving Sudoku problems.

The Sudoku is a famous logic-placement game, originally popularized in Japan and today widely employed as pastime and as testbed for search algorithms. The classic Sudoku consists in filling a 9 × 9 grid, divided into nine 3 × 3 regions, so that each column, row, and region contains different digits from 1 to 9. This game is known to be NP-complete, with existing various complete and incomplete search algorithms able to solve different instances of it. In this paper, we present a new cuckoo search algorithm for solving Sudoku puzzles combining prefiltering phases and geometric operations. The geometric operators allow one to correctly move toward promising regions of the combinatorial space, while the prefiltering phases are able to previously delete from domains the values that do not conduct to any feasible solution. This integration leads to a more efficient domain filtering and as a consequence to a faster solving process. We illustrate encouraging experimental results where our approach noticeably competes with the best approximate methods reported in the literature.

Comparing evolutionary strategies on a biobjective cultural algorithm.

Evolutionary algorithms have been widely used to solve large and complex optimisation problems. Cultural algorithms (CAs) are evolutionary algorithms that have been used to solve both single and, to a less extent, multiobjective optimisation problems. In order to solve these optimisation problems, CAs make use of different strategies such as normative knowledge, historical knowledge, circumstantial knowledge, and among others. In this paper we present a comparison among CAs that make use of different evolutionary strategies; the first one implements a historical knowledge, the second one considers a circumstantial knowledge, and the third one implements a normative knowledge. These CAs are applied on a biobjective uncapacitated facility location problem (BOUFLP), the biobjective version of the well-known uncapacitated facility location problem. To the best of our knowledge, only few articles have applied evolutionary multiobjective algorithms on the BOUFLP and none of those has focused on the impact of the evolutionary strategy on the algorithm performance. Our biobjective cultural algorithm, called BOCA, obtains important improvements when compared to other well-known evolutionary biobjective optimisation algorithms such as PAES and NSGA-II. The conflicting objective functions considered in this study are cost minimisation and coverage maximisation. Solutions obtained by each algorithm are compared using a hypervolume S metric.

Computer-related ophthalmic syndrome in teachers of a University of the Province of Cañete.

Virtual education has impacted the vision of people during the coronavirus pandemic, as by spending more time on the computer, it compromises the eye health of the person causing long-term visual problems. So the objective of this investigation is to assess computer-related ophthalmic syndrome in teachers of a University of the Province of Cañete. Methods: This is a quantitative, nonexperimental, descriptive, cross-sectional study on a total population of 63 teachers, who answered a digital survey using the sociodemographic data and the Computer Vision Syndrome Questionnaire. Clinical Discussion: From the results it can be observed that the results of computer ophthalmic syndrome in the university teachers of the province of Cañete, where 51 (81%) of the teachers do not present the computer vision syndrome and 12 (19%) presented with the computer vision syndrome. Conclusion: The population conducting virtual education as well as the students should be educated on the measures to be taken to prevent computer ophthalmic syndrome and its consequences.

Prevalence of Anxiety and Depression in Prostate Cancer Patients and Their Spouses: An Unaddressed Reality.

OBJECTIVES: To estimate the prevalence of unsuspected anxiety or depression in prostate cancer patients and their spouses, as well as factors involved in its onset. Materials and Methods. A prospective study of 184 patients and 137 spouses evaluated in our hospital during 2019 using the Memorial Anxiety Scale for Prostate Cancer (MAX-PC), Hospital Anxiety and Depression Scale (HADS) and Patient Health Questionnaire depression module (PHQ-9). This study provides an internal validity assessment of the scales and their correlation (alpha and rho coefficients; index r). The contributions of age, education level, months after diagnosis, pain, prostate-specific antigen (PSA) level, stage of the disease and treatment performed to the positivity of the questionnaires were studied using the Wilcoxon-Mann-Whitney and chi-square tests. RESULTS: The prevalence of anxiety was 10.9% (MAX-PC) and 28.3% (MAX-PC-PSA). The HADS-A questionnaire indicated pathology in 14.1% of the patients and 16.05% of the spouses. Depression was detected in 7% (HADS-D) and 9.2% (PHQ-9) of patients as well as in 8.8% (HADS-D) and 16.05% (PHQ-9) of their spouses. The greatest concordance between men and women was with the PHQ-9 (Spearman's rho: 0.78; p = 0.01). Education level is significantly related to the presence of anxiety and depression, regardless of the questionnaire applied. The probability of detecting pathology in the MAX-PC varied from 6% in patients with elementary education to 23.5% in university students (p = 0.04). The greatest differences were detected when applying the PHQ-9 to patients (4% pathological, elementary education vs. 35.3% pathological, university education). Our study confirms the lack of a relationship between rates of anxiety and depression and factors such as PSA level, age of the patient and number of comorbidities. CONCLUSION: There is a high prevalence of unsuspected anxiety and depression in patients with prostate cancer and their wives. Education level correlates with such prevalence.

Solving the Manufacturing Cell Design Problem through Binary Cat Swarm Optimization with Dynamic Mixture Ratios.

In this research, we present a Binary Cat Swarm Optimization for solving the Manufacturing Cell Design Problem (MCDP). This problem divides an industrial production plant into a certain number of cells. Each cell contains machines with similar types of processes or part families. The goal is to identify a cell organization in such a way that the transportation of the different parts between cells is minimized. The organization of these cells is performed through Cat Swarm Optimization, which is a recent swarm metaheuristic technique based on the behavior of cats. In that technique, cats have two modes of behavior: seeking mode and tracing mode, selected from a mixture ratio. For experimental purposes, a version of the Autonomous Search algorithm was developed with dynamic mixture ratios. The experimental results for both normal Binary Cat Swarm Optimization (BCSO) and Autonomous Search BCSO reach all global optimums, both for a set of 90 instances with known optima, and for a set of 35 new instances with 13 known optima.

A Hybrid alldifferent-Tabu Search Algorithm for Solving Sudoku Puzzles.

The Sudoku problem is a well-known logic-based puzzle of combinatorial number-placement. It consists in filling a n(2) × n(2) grid, composed of n columns, n rows, and n subgrids, each one containing distinct integers from 1 to n(2). Such a puzzle belongs to the NP-complete collection of problems, to which there exist diverse exact and approximate methods able to solve it. In this paper, we propose a new hybrid algorithm that smartly combines a classic tabu search procedure with the alldifferent global constraint from the constraint programming world. The alldifferent constraint is known to be efficient for domain filtering in the presence of constraints that must be pairwise different, which are exactly the kind of constraints that Sudokus own. This ability clearly alleviates the work of the tabu search, resulting in a faster and more robust approach for solving Sudokus. We illustrate interesting experimental results where our proposed algorithm outperforms the best results previously reported by hybrids and approximate methods.

The role of a basic surgical skills laboratory as viewed by medical students (6th year).

In the last academic year, a training period in a surgical skills laboratory, using plastic models, was included as a part of the 'Cirurgia 3' ('Surgery 3', 6th year) programme of Faculdade Medicina Lisboa. To evaluate the training period, a structured, anonymous questionnaire was administered at the end, seeking students' responses on their satisfaction in attending the course. A global view of the answers points out students' favourable opinion of the laboratory-training period: concerning students' perceived goals for attending the course, a high degree of satisfaction was reported (globally 73% of computed scores were rated as 'good' or 'very good'); the teaching/learning environment and the delivered content got 90% 'very good' and 'good' ratings; teaching staff performance got the highest percentage of rating scores 'very good' and 'good' (95%). These ratings were dependent on variables that are unlikely to be a reflection only of glamour and seduction (clear explanations and clear demonstration of each component of the skill) and were less dependent on other variables such as 'enthusiasm for teaching' and 'relationship with students', which could be expected to be influenced by the charisma of the tutors. Helping students learn and train in surgical skills in a laboratory is challenging and our results affirm that the environment and the content were valuable for the understanding of the subject, while sessions planning and appropriate teaching technique are essential when practical skills are to be taught and learned.

Epidemiology and complications of facial fractures: a 5-year retrospective study / Epidemiología y complicaciones de las fracturas faciales: un estudio retrospectivo de 5 años

ABSTRACT Introduction: regional epidemiological studies involving facial trauma are needed to develop more efficient ways of providing health care services. The time elapsed from the occurrence of facial trauma to its definitive treatment can affect clinical outcomes in terms of interventions, resolution, and complications. The aim of this study was to verify if there is a relationship between the different fracture types, their treatments or time intervals for clinical resolution and the onset of complications. Methods: a retrospective study was conducted by means of the clinical records of the Eugenio Espejo Hospital in Quito, verifying the epidemiological data on the clinical evolution of facial trauma patients between 2012 and 2016, and registering data such as age, gender, fracture type, time elapsed until its definitive treatment, and onset of complications. Clinical records lacking these data were excluded. Results: most cases occurred outside Quito (64%). There was no relationship between harmful habits, fracture displacement, type of access or fixation, or presence of comorbidities and the onset of complications. The odds ratio (95% confidence interval) for complications was OR = 0.301(0.170-0.536), so there is a 70% increased chance of developing some complications if treatment is performed one week after trauma occurs. Conclusion: reducing facial fractures before a week can decrease the onset of complications and sequelae.

RESUMEN Introducción: los estudios epidemiológicos regionales que involucren trauma facial son importantes para ayudar a desarrollar formas más eficientes de brindar cuidados en salud. El tiempo transcurrido desde que ocurre un traumatismo facial hasta su tratamiento definitivo puede afectar los resultados clínicos en términos de intervenciones, resolución y complicaciones. El objetivo del presente estudio consistió en verificar si existe una relación entre los diferentes tipos de fracturas, sus tratamientos y los intervalos de tiempo para su resolución clínica con la aparición de complicaciones. Métodos: se realizó un estudio retrospectivo con las historias clínicas del hospital Eugenio Espejo de Quito, verificando los datos epidemiológicos de la evolución clínica de pacientes con trauma facial entre el 2012 y 2016. Para ello se tomaron datos como edad, sexo, tipo de fractura, tiempo transcurrido hasta su tratamiento definitivo y aparición de complicaciones. Se descartaron las historias que no tuvieron todos los datos para este trabajo. Resultados: la mayoría de los casos ocurrió fuera de Quito (64%). Se observó que no existe relación entre hábitos nocivos, desplazamiento de fractura, tipo de abordaje o de fijación y presencia de comorbilidades con la aparición de complicaciones. El resultado de razones de probabilidad (intervalo de confianza) para las complicaciones fue de OR=0.301(0.170-0.536); por lo tanto, existe un 70% más de probabilidad de presentar alguna complicación si el tratamiento se realiza después de una semana de ocurrido el trauma. Conclusión: la reducción de las fracturas faciales antes de una semana puede disminuir la ocurrencia de complicaciones y secuelas.