Positivity Preserving Schemes for Black-Scholes Equation

Mathematical finance is a field of applied mathematics, concerned with financial markets. In the market of financial derivatives the most important problem is the so called option valuation problem, i.e. to compute a fair value for the option. The solution of the Black-Scholes equation determines the option price, respectively according to the used initial conditions. In this paper, first we show that the positivity is not ensured with classical finite difference schemes when applied to the Black-Scholes equation for very small time steps. Next, by reforming the discretization of the reaction term of equation, a family of efficient explicit schemes are derived that is free of spurious oscillations around discontinuities and preserving positivity. Keywords: Positivity, Nonstandard discretization, Black-Scholes equatio

An Explicit Positivity Preserving Scheme: Application to Biological Model

This paper deals with the construction of nonstandard finite difference method (NFSD) for nonlinear initial value problems modeled by a system of nonlinear ordinary differential equations. The proposed scheme preserves the positivity property as well as the requirement of conservation law and boundedness. In order to illustrate the accuracy of the new scheme, the numerical results compared with the standard ones. Keywords: Positivity, Boundedness, Nonstandard finite difference

Reduction of vancomycin resistance inVanAand VanBcontainingVancomycin Resistant Enterococci (VRE) isolatesin presence of lactoferrin protein

چکیده زمینه و هدف : پروتئین لاکتوفرین(Lactoferrin(LF)) دارای اثرات ضدمیکروبی اثبات شده ای است. هدف از این مطالعه بررسی تأثیر لاکتوفرین روی حداقل غلظت مهاری) Minimum inhibitory concentration (MIC))وانکومایسین در سویه های انتروکوک مقاوم به وانکومایسین دارای ژنهای مقاومت VanA و VanB بود. ﻣﻮﺍﺩ ﻭ ﺭﻭﺵﻫﺎ: در این مطالعه مقطعی ، پس از جداسازی و تشخیص265 سویه انتروکوک از نمونه های بالینی ، MIC وانکومایسین و تیکوپلانین سویه هابا روش تست اپسیلومتر ( Epsilometer test(Etest)) بدست آمد. نمونه های انتروکوک مقاوم به وانکومایسین Vancomycin Resistance Entrococcus(VRE)) ) ، با روش real time PCR ازلحاظ وجود ژنهای مقاوم به وانکومایسین VanA و VanB بررسی شد و سپس تأثیر لاکتوفرین را بر روی MIC آنتی بیوتیک وانکومایسین سویه های VRE مورد بررسی و بااستفاده از نرم افزارآماری SPSS نسخه 20 (version 20, SPSS Inc., Chicago, IL) و آزمون های آماری رگرسیون خطی و همبستگی پیرسون با سطح معنی داری P-value <0.05 آنالیز گردید. ﻧﺘﺎﻳﺞ: نمونه VanA در غلظت µg/ml) 2048)پروتئین لاکتوفرین MIC وانکومایسین را 85 و 80 برابر به ترتیب در روش تغییر یافته Etest و میکروتیتر کاهش داده و در نمونه VanB در غلظت µg/ml) 512) پروتئین لاکتوفرین MIC وانکومایسین را 10و 10.3 برابر به ترتیب در روش تغییر یافته Etest و میکروتیتر کاهش داده است. شاخص لاکتوفرین ارتباط همبستگی مثبت معنی داری را با کاهش MIC وانکومایسین نشان داد (001/0 Pvalue< و r=0.183 ). نتیجه گیری: غلظت های متفاوت پروتئین لاکتوفرین در شرایط آزمایشگاهی باعث کاهش مقاومت در سویه هایVRE دارای ژن VanA و VanB می شود ،پیشنهاد پتانسیل استفاده از این پروتئین به عنوان یک عامل کمکی به وانکومایسین وجود دارد

An Anthropometric Investigation of Index Finger Length Ratio to Ring Finger (2d:4d) in Men with Schizophrenia Living in Khorasan Razavi

Introduction: Schizophrenia is a group of mental disorders that its main characteristics are failure to understand reality and inability to do daily tasks. Anthropometry, which is a type of biometrics, is a science that measures the dimensions and angles of body parts, as well as skin lines and fingerprints on living people. Perhaps knowledge about natural features of finger dimensions provides useful information in the field of medical anthropometry. Therefore, anthropometric properties of the fingers can be used to identify and develop research in this topic. And given that finger length, like brain development, is formed by a family of developmental genes. So, the objective was to find a link between brain violation and finger length. Methods: This study was a case-control and cross-sectional sampling was done in the one-year. The index and ring finger lengths of both hands in 62 men with schizophrenia and 72 healthy subjects who were not diagnosed and aged 18 to 65 years old living in Khorasan Razavi were measured by digital caliper. Results: Significant differences were observed between the average index finger lengths (2d:4d) in men’s right hand of healthy men and men with schizophrenia. Among other variables, significant differences weren’t observed between healthy and patients. Conclusion: It may seem that the results above are used by methods for genetic studies of biometric changes in patients with schizophrenia from the index finger length ratio to the right and left ring fingers for further studies to make an estimation and generation. It’s essential to spread the similar statistical research wider statistical societies. Conflict of Interest Declaration: Not declared

Differential Responses of Anopheles stephensi (Diptera: Culicidae) to Skin Emanations of a Man, a Cow, and a Guinea Pig in the Olfactometer

Background: Biting habit of mosquitoes plays an important role in the epidemiology of mosquito-borne diseases. Mosquitoes use a set of elaborate sensory modalities to find their preferred hosts by exploiting cues emanating from a nearby host. It has been suggested that the chemical profile of skin can provide further support for anthropophilic mosquito species to find their suitable hosts. This study aimed at revealing the value of skin emanation for a zoophilic species like Anopheles stephensi as a model. Methods: Skin emanations of a man, a cow and a Guinea pig were collected by ethanol soaked cottons. Upwind responses of mosquitoes to 100 and 200 mu l of filtered skin materials were non-competitively explored in a dual-choice olfactometer. L-lactic acid and other chemical content of the skin samples were identified by an enzymatic kit and GC-MS, respectively. Results: Unexpectedly, only human skin emanation was resulted in the statistically significant activation and attraction responses of An. stephensi in the wind tunnel. L-lactic acid content of this skin sample was 10 and 29 times more than the cow and the Guinea pig, respectively. The possible role of lactic acid and a few other identified compounds have been discussed here. Conclusion: Anopheles stephensi showed higher and more specific upwind responses to human skin emanation in the olfactometer. Undoubtedly, the thorough explanation of this unexpected finding needs further investigation. But, if new data verify this result, then, it may be necessary to reconsider the role of skin emanation and thence the human blood index and vectorial capacity of this zoophilic mosquito

Fabrication of an olfactometer for mosquito behavioural studies

Background & objectives: Olfaction is the major sensory modality involved in the resource searching behaviour of insects including vector mosquitoes (Diptera: Culicidae). To date, our current country-wide knowledge on the host-seeking behaviour of Iranian mosquitoes is mainly confined to host preference which has exclusively come from field studies. Olfactometer is a scientific tool by which more naive aspects of man-vector contact can be clarified under controlled and less biased conditions. Methods: The wind tunnel and stimulus delivery system was constructed from acrylic materials based on previously introduced models with some modifications. Air supply and required light were ensured by a powerful compressor and incandescent bulbs, respectively. Desired level of temperature was maintained by controllable heating radiators. For humidity production a unique in-built piezo system was devised in the course of the air flow. Fine regulators facilitated the continuous generatation of the humidity at a preset level. Results: Titanium tetrachloride smoke plus monitoring of the wind speed revealed that the flow of air was proper and invariable. A desired level of humidity and temperature could be set up in just 10 and 15-45 min, respectively. These physical parameters varied only +/-2% (humidity) and +/-0.15 degrees C (temperature) in a typical 20 min duration. Conclusion: The first sophisticated olfactometer in the field of medical entomology in Iran is reported here. Fast set up and stability of physical parameters are its salient features. It is expected that with the aid of this olfactometer further information on the physiological principles of the host-seeking behaviour of mosquitoes become available soon

Prediction of fly-rock using gene expression programming and teaching– learning-based optimization algorithm

Peer ReviewedObjectius de Desenvolupament Sostenible::12 - Producció i Consum ResponsablesObjectius de Desenvolupament Sostenible::12 - Producció i Consum Responsables::12.2 - Per a 2030, assolir la gestió sostenible i l’ús eficient dels recursos naturalsPostprint (published version

The Self-control Model of Shiite Youth with a Grounded Theory Approach

For downloading the full-text of this article please click here.Background and Objective: Self-control plays a significant role in physical and spiritual health. Studies have shown that spiritual attitudes and religious teachings play a role in promoting self-control. The purpose of this study was to determine the components of self-control construct in Shiite youth.Methods: Based on the purpose of the study, i.e. determining the self-control construct, and based on criterion-oriented studies in this regard, in the present study, qualitative approach was applied with grounded theory method for collecting data. The participants were 32 youths whose self-control was evaluated using a semi-structured interview. In this study, all the ethical considerations were observed and no conflict of interest was reported by the authors.Results: The findings of this study showed that self-control construct in Shiite youth has four main components and fourteen subcomponents: 1) Attitude (belief in the benefits of avoidance, belief in harms of committing, attention to the emotions involved in the problem, problem solving, self-esteem); 2) self-motivation ability (the benefits of avoiding, paying attention to the damage done, paying attention to the emotions involved in the problem, and positive self-assertion); 3) the ability to control oneself and the environment (the ability to control attention, the ability to control impulse, the ability to control the environment, the active conditioning, socializing with good friends); and 4) adaptability, self-awareness, problem solving ability, flexibility, acceptance of excitement and behavior management, secondary positive evaluation.Conclusion: By comparing the results of the presents study with the text-based studies such as the one by Rafi’ee Honar, who considers the self-control construct as self-monitoring, target recognition, motivation, excitement control, cognitive control and persistent control, it can be found that the model developed in the present study makes the psychological self-control constructs more clear and, consequently, provides a more appropriate ground for developing self-control scales of the Shiite youth and appropriate psychological training programs for promoting self-control.For downloading the full-text of this article please click here.Please cite this article as: Farhoush M, Masteri-Farahani R, Jamshidi MA, Shokri-Khoubestani M, Ghorbani S. The Self-control Model of Shiite Youth with a Grounded Theory Approach. Journal of Pizhūhish dar dīn va salāmat. 2020;6(1):60-73. https://doi.org/10.22037/jrrh.v6i1.2123

بررسی اثرات خشک‌سالی و شوری برکیفیت شیمیایی آبخوان دشت زنجان

Background and Objective: Due to the occurrence of dry season and exploitation of water resources for higher agricultural yields, the groundwater level in the Zanjan plain has subsided. The lowered of water level of aquifer have reduced the efficiency of wells and paralleled with water quality degradation. The underground structure of aquifer was destroyed and the quality of water resources contains more salt than fresh waters. Materials and Methods: In order to survey on the salinity of water in this region, data from 45 sampling wells (1384-1394) has been used. In the first step by collecting valid information about the chemical quality of related aquifer, investigation on fluctuation trends of ions concentrations of Ca, Mg, Na, HCO3, Cl, SO4, from 1384 to 1394has been conducted. Then, pH and EC have been surveyed for ten years (1384-1394) to determine the general chemical quality of region groundwater.  Finally, fluctuation trends of elements and water salinity have been plotted on descriptive diagrams, piper, statistical models, and other plans. In this study, all the ethical considerations have been observed and no conflict of interest was reported by the authors. Results: The data of this study demonstrated that average concentrations of sulfate and chloride are2.3 and 1.1meq/lit respectively. The concentration of these ions in water samples indicated the desirable quality of groundwater at present. However, if the current trend regarding the subsiding of groundwater level in the Zanjan plain, we could face a decrease in water quality and an increase in salinity in the coming years. Conclusion: According to the results of the study, it can be said that the increasing trend in the concentrations of salts in the water and the declining trend of the output of the wells could reduce the chemical quality of water in near future. How to cite this article: Jalalian A, Samiee H, Shokri-Khoubestan M, Karimi MR. Investigation of the Effects of Drought and Salinity on the Chemical Quality of the Water Resources in the Zanjans' Plain Aquifers. J Saf Promot Inj Prev. 2020; 8(2):119-29.  سابقه و هدف: با توجه به وقوع دوره‌هاي خشک‌سالي و افزايش بهره‌برداري از آبخوان، گسترش کشاورزي و افزايش برداشت آب‌هاي زيرزميني،  تراز سطح آب زيرزميني در دشت زنجان کاهش‌يافته است که اين امر علاوه بر پايين رفتن تراز سطح آب زيرزميني، کاهش راندمان چاه‌ها، تخريب کيفي و افزايش املاح آب زيرزميني را نيز در پي دارد که خود سبب تخريب کيفيت منابع و برهم خوردن تعادل آب‌هاي شور و شيرين گرديده است. روش بررسي: جهت بررسي کيفيت و روند تغييرات پارامترهاي کيفي سفرة آبي اين دشت از اطلاعات 45 نقطه نمونه‌برداري ازچاه‌هاي موجود در منطقه استفاده‌ شده است. در مرحلة اول با جمع‌آوري اطلاعات موثق درزمينة کيفيت شيميايي سفرة آب‌هاي زيرزميني منطقه به بررسي روند تغييرات غلظت يون‌هاي کلسيم، منيزيم، سديم، بي‌کربنات، کلرايد و سولفات در طي سال‌هاي 1384 تا1394 پرداخته شد. در ادامه pH و هدايت الکتريکي جهت تعيين کيفيت شيميايي چاه‌هاي منطقه طي ده سال مورد بررسي قرار گرفت. در نهايت ميزان تغييرات يون‌ها و کيفيت آب طي بازه زماني ده ساله بررسي و نتايج با استفاده از نمودارهاي پايپر، شولر، و يلکاکس و دورو تحليل گرديد. در اين پژوهش همة موارد اخلاقي رعايت شده است و مؤلفان مقاله هيچ‌گونه تضاد منافعي گزارش نکرده‌اند. يافته‌ها: حدود 70 درصد نمونه‌ها تيپ بي‌کربناته دارند. اين امر نشان‌دهنده کيفيت بالاي آب‌هاي زيرزميني در دشت زنجان است با توجه به اينکه نمودار ويل کاکس از دو فاکتور هدايت الکتريکي (EC) و نسبت جذب سديم (SAR) جهت طبقه‌بندي مصرف آب کشاورزي استفاده مي‌نمايد، دياگرام ويل‌کاکس نمونه آب‌هاي زيرزميني گروه C2-S1 و C3-S1 قرار مي‌گيرد. لذا وضعيت آب زيرزميني دشت زنجان ازلحاظ مصرف کشاورزي مناسب است. اما در صورت ادامه روند فعلي در خصوص کاهش تراز سطح آب زيرزميني در محدودة دشت زنجان، در سال‌هاي آينده با کاهش کيفيت آب و افزايش شوري مواجه خواهيم شد. نتيجه‌گيري: بررسي کيفيت شيميايي چاه‌هاي دشت نشان مي‌دهد که اکثر پارمترهاي کيفي مرتبط با شوري در محدودة قابل‌قبول قرار دارد. با توجه به نتايج مطالعه مي‌توان گفت روند افزايشي در ميزان املاح موجود در آب و روند نزولي دبي جريان و افت آب‌هاي زيرزميني، در آينده‌اي نه‌چندان دور کاهش کيفيت شيميايي آب را جهت استفاده‌هاي گوناگون سبب مي‌شود. How to cite this article: Jalalian A, Samiee H, Shokri-Khoubestan M, Karimi MR. Investigation of the Effects of Drought and Salinity on the Chemical Quality of the Water Resources in the Zanjans' Plain Aquifers. J Saf Promot Inj Prev. 2020; 8(2):119-29. &nbsp