A Study on negative numbers Conception of students and their misconceptions

Understanding negative numbers and doing operations on them is one of the fundamental subjects in mathematics that students face many problems when they encounter them at school. One of the problems that leads to very serious learning difficulties in mathematics is those misconceptions students may have from previous inadequate teaching, informal thinking, or poor remembrance. Recognition of misconception and the origins that create them in the fields and at different levels of education, can improve learning.  Misunderstanding in this study is incomplete or incorrect interpretation of a concept that cause systematic errors in the performance. This study investigates the student’s understanding and misconception of negative numbers. Descriptive statistics, survey, is used as a method of this study. The population of the study is all second level students of guidance school in the academic year 1391-92 and all the seventh level students of Darmian town in the academic year 1392-93. 443 students in second level of guidance school and 55 students in seventh level were chosen as a sample of the study based on cluster random sampling. A self-designed questionnaire by the researcher is used as the instrument for the study, the questionnaire was based on “Bofferding” and “Kilhamn” questionnaire. Results showed that most of the students don’t have a true understanding of negative numbers in school and face problems in applying their knowledge to solve mathematical problems. Also the results of the current study showed that some of the students consider "-" as a reducing operator and some consider "+" as an increasing operator

Waiting Time for Specialist Consultation and Visit Requested in the Emergency Department; a Cross-Sectional Study

Introduction: Waiting time in the hospital directly affects the quality of healthcare providing centers. One of the waiting times in hospital is the time spent waiting for receiving various consultations and visits requested by emergency medicine specialists from specialist services. Objective: The present study was designed and performed to assess the waiting times for receiving specialist visits and consultations requested in the emergency department based on the corresponding service in a referral hospital in Isfahan, Iran. Method: In the present cross-sectional study, patients presenting to emergency department of Dr. Shariati Hospital, Isfahan, Iran, from October 2017 to March 2018, who were in need of visit or consultation from other specialist services based on the opinion of the emergency medicine specialist, were studied. By attending the patients' bedside, the researcher filled out a checklist consisting of demographic data and waiting time of the patients and other probable related factors. Finally, raw data were entered to the computer and after correction of errors were statistically analyzed via SPSS software. Results: Overall, 400 patients with the mean age of 53.3 ± 24.3 years were included in the study, 58.8% of which were male. Mean waiting time for receiving a visit or consultation among the studied patients was 242.0 ± 202.4 (min: 5 and max: 1200) minutes. Mean waiting time for a visit or consultation did not significantly correlate with the corresponding physician being resident or on-call. However, it showed a statistically significant correlation with triage level (p = 0.013), work shift (p = 0.000), type of service requested/the specialist service asked for a consultation or visit (p = 0.049), and the consultation or visit being emergent or non-emergent (p = 0.000). In addition, emergent visits or consultations by on-call physicians had been performed significantly faster than those by resident physicians; while non-emergent visits or consultations by resident physicians had been performed significantly faster than those by on-call physicians (p = 0.001). Conclusion: The results of the present study showed that patients with triage level 2, emergent visit of consultation and a visit or consultation request in the morning or evening shift wait a shorter time for receiving the visit or consultation. In addition, neurosurgery, nephrology, and pediatrics services had the shortest waiting times, while gastroenterology, gynecology, and infectious disease services had the longest waiting times for giving the visit or consultation requested from them

Force-based Cooperative Search Directions in Evolutionary Multi-objective Optimization

International audienceIn order to approximate the set of Pareto optimal solutions, several evolutionary multi-objective optimization (EMO) algorithms transfer the multi-objective problem into several independent single-objective ones by means of scalarizing functions. The choice of the scalarizing functions' underlying search directions, however, is typically problem-dependent and therefore difficult if no information about the problem characteristics are known before the search process. The goal of this paper is to present new ideas of how these search directions can be computed \emph{adaptively} during the search process in a \emph{cooperative} manner. Based on the idea of Newton's law of universal gravitation, solutions attract and repel each other \emph{in the objective space}. Several force-based EMO algorithms are proposed and compared experimentally on general bi-objective $\rho$MNK landscapes with different objective correlations. It turns out that the new approach is easy to implement, fast, and competitive with respect to a $(\mu+\lambda)$-SMS-EMOA variant, in particular if the objectives show strong positive or negative correlations

Attraction and diffusion in nature-inspired optimization algorithms

Nature-inspired algorithms usually use some form of attraction and diffusion as a mechanism for exploitation and exploration. In this paper, we investigate the role of attraction and diffusion in algorithms and their ways in controlling the behaviour and performance of nature-inspired algorithms. We highlight different ways of the implementations of attraction in algorithms such as the firefly algorithm, charged system search, and the gravitational search algorithm. We also analyze diffusion mechanisms such as random walks for exploration in algorithms. It is clear that attraction can be an effective way for enhancing exploitation, while diffusion is a common way for exploration. Furthermore, we also discuss the role of parameter tuning and parameter control in modern metaheuristic algorithms, and then point out some key topics for further research

Fitness Varying Gravitational Constant in GSA

Gravitational Search Algorithm (GSA) is a recent metaheuristic algorithm inspired by Newton's law of gravity and law of motion. In this search process, position change is based on the calculation of step size which depends upon a constant namely, Gravitational Constant (G). G is an exponentially decreasing function throughout the search process. Further, inspite of having different masses, the value of G remains same for each agent, which may cause inappropriate step size of agents for the next move, and thus leads the swarm towards stagnation or sometimes skipping the true optima. To overcome stagnation, we first propose a gravitational constant having different scaling characteristics for different phase of the search process. Secondly, a dynamic behavior is introduced in this proposed gravitational constant which varies according to the fitness of the agents. Due to this behavior, the gravitational constant will be different for every agent based on its fitness and thus will help in controlling the acceleration and step sizes of the agents which further improve exploration and exploitation of the solution search space. The proposed strategy is tested over 23 well-known classical benchmark functions and 11 shifted and biased benchmark functions. Various statistical analyses and a comparative study with original GSA, Chaos-based GSA (CGSA), Bio-geography Based Optimization (BBO) and DBBO has been carried out

Survey of Third-Party Parenting Options Associated With Fertility Preservation Available to Patients With Cancer Around the Globe

Purpose: In the accompanying article, “Analysis of Fertility Preservation Options Available to Patients With Cancer Around the Globe,” we showed that specific fertility preservation services may not be offered at various sites around the world because of cultural and legal barriers. We assessed global and regional experiences as well as the legal status of third-party reproduction and adoption to serve as a comprehensive international data set and resource for groups that wish to begin oncofertility interventions. Methods: We provide data on the legalities of third-party assisted reproductive technologies and other family-building options in the 28 oncofertility-practicing countries surveyed. Results: We found regional and country differences that will be important in the development of tailored resources for physicians and for patient brochures that are sensitive to these local restrictions and cultural norms. Conclusion: Because many patients first consult Web-based materials, the formal assessment of the availability of these options provides members of the global oncofertility community with data to which they might otherwise not have ready access to better serve their patients

A survey of fertility preservation options available to cancer patients around the globe

Purpose: Oncofertility focuses on providing fertility and endocrine-sparing options to patients who undergo life-preserving but gonadotoxic cancer treatment. The resources needed to meet patient demand often are fragmented along disciplinary lines. We quantify assets and gaps in oncofertility care on a global scale. Methods: Survey-based questionnaires were provided to 191 members of the Oncofertility Consortium Global Partners Network, a National Institutes of Health–funded organization. Responses were analyzed to measure trends and regional subtleties about patient oncofertility experiences and to analyze barriers to care at sites that provide oncofertility services. Results: Sixty-three responses were received (response rate, 25%), and 40 were analyzed from oncofertility centers in 28 countries. Thirty of 40 survey results (75%) showed that formal referral processes and psychological care are provided to patients at the majority of sites. Fourteen of 23 respondents (61%) stated that some fertility preservation services are not offered because of cultural and legal barriers. The growth of oncofertility and its capacity to improve the lives of cancer survivors around the globe relies on concentrated efforts to increase awareness, promote collaboration, share best practices, and advocate for research funding. Conclusion: This survey reveals global and regional successes and challenges and provides insight into what is needed to advance the field and make the discussion of fertility preservation and endocrine health a standard component of the cancer treatment plan. As the field of oncofertility continues to develop around the globe, regular assessment of both international and regional barriers to quality care must continue to guide process improvements

Social Algorithms

This article concerns the review of a special class of swarm intelligence based algorithms for solving optimization problems and these algorithms can be referred to as social algorithms. Social algorithms use multiple agents and the social interactions to design rules for algorithms so as to mimic certain successful characteristics of the social/biological systems such as ants, bees, bats, birds and animals.Comment: Encyclopedia of Complexity and Systems Science, 201

Survey of third-party parenting options associated with fertility preservation available to patients with cancer around the globe

bstract PURPOSE In the accompanying article, “Survey of Fertility Preservation Options Available to Patients With Cancer Around the Globe,” we showed that specific fertility preservation services may not be offered at various sites around the world because of cultural and legal barriers. We assessed global and regional experiences as well as the legal status of third-party reproduction and adoption to serve as a comprehensive international data set and resource for groups that wish to begin oncofertility interventions. METHODS We provide data on the legalities of third-party assisted reproductive technologies and other familybuilding options in the 28 oncofertility-practicing countries surveyed. RESULTS We found regional and country differences that will be important in the development of tailored resources for physicians and for patient brochures that are sensitive to these local restrictions and cultural norms. CONCLUSION Because many patients first consult Web-based materials, the formal assessment of the availability of these options provides members of the global oncofertility community with data to which they might otherwise not have ready access to better serve their patients