A probabilistic model to resolve diversity-accuracy challenge of recommendation systems

Recommendation systems have wide-spread applications in both academia and industry. Traditionally, performance of recommendation systems has been measured by their precision. By introducing novelty and diversity as key qualities in recommender systems, recently increasing attention has been focused on this topic. Precision and novelty of recommendation are not in the same direction, and practical systems should make a trade-off between these two quantities. Thus, it is an important feature of a recommender system to make it possible to adjust diversity and accuracy of the recommendations by tuning the model. In this paper, we introduce a probabilistic structure to resolve the diversity-accuracy dilemma in recommender systems. We propose a hybrid model with adjustable level of diversity and precision such that one can perform this by tuning a single parameter. The proposed recommendation model consists of two models: one for maximization of the accuracy and the other one for specification of the recommendation list to tastes of users. Our experiments on two real datasets show the functionality of the model in resolving accuracy-diversity dilemma and outperformance of the model over other classic models. The proposed method could be extensively applied to real commercial systems due to its low computational complexity and significant performance.Comment: 19 pages, 5 figure

Antinociceptive and anti-inflammatory effects of hydroalcoholic extract of Vitex agnus castus fruit in mice

زمینه و هدف: از آنجا که در طب سنتی اثرات ضد دردی و ضد التهابی به گیاه پنج انگشت نسبت داده شده است. این مطالعه با هدف بررسی اثرات ضد دردی و ضد التهابی عصاره هیدروالکلی میوه گیاه پنج انگشت ((Vitex agnus- castus در موش کوچک نر نژاد آزمایشگاهی NMRI انجام شده است. روش بررسی: در این مطالعه تجربی از 112 سر موش نر بالغ نژاد NMRI استفاده شد. در تست التهاب، حیوانات به 7 گروه شاهد، کنترل مثبت (دریافت کننده دگزامتازون با دوز mg/kg15) و پنج گروه دریافت کننده دوزهای 265، 365، 465، 565 و 665 میلی گرم بر کیلوگرم عصاره هیدروالکلی میوه پنج انگشت تقسیم و برای ایجاد التهاب از گزیلن استفاده شد. جهت بررسی اثر ضد دردی عصاره، تست فرمالین مورد استفاده قرار گرفت. در این تست نیز حیوانات به 7 گروه شاهد، کنترل مثبت (دریافت کننده مورفین با دوز mg/kg 10) و پنج گروه دریافت کننده عصاره تقسیم شدند. تزریقات به روش داخل صفاقی و 30 دقیقه قبل از شروع هر تست انجام شد. داده ها با استفاده از آزمون های آماری آنالیز واریانس یک طرفه و سپس توکی تجزیه و تحلیل شدند. یافته ها: تمام دوزهای عصاره اثر ضد التهابی قابل ملاحظه ای را در مهار التهاب گوش، ناشی از گزیلن در مقایسه با گروه شاهد نشان داد (05/0

Eukaryotic expression of the core gene of hepatitis C virus genotype 1a

Background: Worldwide, hepatitis C virus (HCV) infection is a serious public health disease unlike hepatitis A and B, there is currently no vaccine against HCV available. Thus, extensive studies are under way to design new and effective treatments against HCV. Core protein is a component of HCV particle which is the first antigen recognized by the immune system.beside protective properties of core protein, anti –core antibodies can be used to monitor the disease progress. The purpose of the present study was to isolate and clone the core (C) gene from HCV genotype 1a in an attempt to construct a recombinant vector and subsequently evaluate its expression in a cell culture system.Methods:RNA genome of HCV genotype 1a was extracted from the blood of an infected patient. Complementary DNA (cDNA) was synthesized. HCV 1a core gene was amplified by PCR using specific primers and it was cloned into a eukaryotic expression vector. Huh7.5 cells were transfected by the designed recombinant vector and the cellular expression of the core gene was confirmed by RT-PCR.Results: Recombinant pcDNA3.1 (+) vector containing the HCV core gene with approximate size of 576bp was successfully designed. RT-PCR was used to confirm the expression of core antigen in an Huh7.5 cell line.Conclusion: The results showed that the core gene was successfully isolated from HCV genotype 1a and was cloned into the eukaryotic expression vector. This recombinant vector effectively replicated in Huh7.5 cell line. and its protective and therapeutic effects can be examined in further investigations

The Effects of Imitative Vs. Cognitive Methods on The Speech Development of Children With Autism

How to Cite This Article: Jalili M, Jahangiri N, Yazdi Aa, Ashrafzadeh F. The Effects of Imitative Vs. Cognitive Methods on The Speech Development of Children With Autism. Iran J Child Neurol. 2014 Winter; 8(1):37-46.ObjectiveThe present study was performed to examine the effects of two speech therapy methods on six verbal behaviors of autistic children, including oral speech, listening, organizing, speaking, semantics, and syntax.Materials & MethodsIn this study, thirty 6-8 years old children with autism were assigned to one of two groups: imitative and cognitive groups. Before starting the main procedures of the study, the children of both groups were homogenized concerning their autism level. In the first phase of the study, the speech development level of the two groups was measured in a pre-test, in which both groups showed similar results. Then, both groups of children received 6 months of speech therapy instruction, during which one group was taught using an imitative method, while the other group was being worked with cognitive method.ResultsAfter 6-month treatment period, a post-test was done, and the t-tests based on the data of the two groups revealed a significant difference between the results.ConclusionThe statistics showed that after the teaching period, autistic that worked with cognitive method gained a better development in their speech abilities, comparing to those worked with the imitative method.Reference:Samadi SA, Mahmoodizadeh A, McConkey R. A national study of the prevalence of Autism among five year old children in Iran. Autism 2012;16(1):5-14.Fombonne E, Simmons H, Ford T, Meltzer H, Goodman R. Prevalence of pervasive developmental disorders in the British nationwide survey of child mental health. J Am Acad Child Adolesc Psychiatry 2001;40(7):820-7.Fombonne, E. The changing epidemiology of Autism. 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