Generation, Ranking and Unranking of Ordered Trees with Degree Bounds

We study the problem of generating, ranking and unranking of unlabeled ordered trees whose nodes have maximum degree of $\Delta$. This class of trees represents a generalization of chemical trees. A chemical tree is an unlabeled tree in which no node has degree greater than 4. By allowing up to $\Delta$ children for each node of chemical tree instead of 4, we will have a generalization of chemical trees. Here, we introduce a new encoding over an alphabet of size 4 for representing unlabeled ordered trees with maximum degree of $\Delta$. We use this encoding for generating these trees in A-order with constant average time and O(n) worst case time. Due to the given encoding, with a precomputation of size and time O(n^2) (assuming $\Delta$ is constant), both ranking and unranking algorithms are also designed taking O(n) and O(nlogn) time complexities.Comment: In Proceedings DCM 2015, arXiv:1603.0053

A diachronic analysis of the cultural aspect of local English coursebooks

Delving into a wide range of the cultural elements, the current study endeavoured to reveal the tortuous path the secondary school English coursebooks have passed in Iran. To this end, the secondary school coursebooks of level one were diachronically investigated for the commonly unnoticed side of culture, ie the perspective aspect of culture, names, and images. In so doing, the above‐mentioned elements of culture in the coursebooks from 1939, when the very first English coursebook was introduced to the country, till the latest series published in 2016 were scrutinised. The results suggested that not only have cultural elements lacked a coherent framework to be translated into English coursebooks, but they have also been an uncharted island on the English coursebook authors’ map. Additionally, the researchers suggest that the haphazard representation of culture might be partly due to the fact that a viable definition of culture, at least in the realm of applied linguistics, does not exist and some studies may need to be carried out on this issue

Experimental and Theoretical Investigation of Impinging Jet Ventilation at Different Cross Sectional Area of Supply Air Duct

يتضمن البحث دراسة عملية ونظرية لحركة الهواء وتوزيع درجة الحرارة داخل حيز باستحدام منظومة تهوية البثق المؤثر لغرفة مكتب واستخدام برامج الحاسوب (ANSYS.15) لحل معادلاث نافير ستوك باستخدام طريقة الفروقات المحددة لمحاكاة وتحليل النموذج المدروس . تم اختبار ثلاثة انواع لمجاري دفع الهواء تم استحدام مجرى هواء مقطع مربع ونصف دائري ومستطيل الشكل بارتقاع(0.14h,0.1h) عن مستوى الارض تم قورنت النتائج النظرية مع القراءات العملية حبث تم التواصل الى ان المقطع المربع هو النوع الاكثر مقبولية  بين الانواع الثلاثة الاخرى في الحالة المدروسة بالنسبة لراحة الشاغلين An experimental and computational analysis of temperature and velocity distribution in an office room have been studied. Office room of dimensions (3m x 1.75m x 3m) with two cross sectional types of supply air duct in the experimental part and three different cross sectional types of supply air duct in the theoretical part is usual as a tested model. The RNG k-  turbulence model was employed to solve the governing equations numerically and validated by comparing the numerical results with experimental data. The impinging jet concept has been proposed as a new ventilation strategy for use in office and industrial buildings. The present work focuses on evaluating the performance of a new impinging jet ventilation. In a theoretical study three types of supply air duct are adopted which are square supply air duct (Type-I), semi-elliptic supply air duct (Type-II) and rectangle supply air duct (Type-III) for two cases of air outlet terminal height from room foot level, 0.14h (case-I) & 0.1h (case-II). The third type (rectangle duct) gives lowest effective and discomfort conditions when compared with the other two types. This study investigated a number of factors influencing draught discomfort and temperature stratification in an office environment equipped with impinging jet ventilation IJV. The factors considered to be: shape of the air supply device, supply airflow rate and supply air temperature. Acceptable Air Distribution Performance Index (ADPI), effective temperature, and ventilation efficiency obtained that the square cross sectional area of supply air duct at 0.1h (case-II) height from foot level gives more acceptable indoor air quality and human thermal comfort when compared with the other types. Also, this type gives good air distribution system not only promotes a comfortable and healthy environment for occupants, but also contributes to energy conservation

Factors Influencing Rural-Urban Migration from Mountainous Areas in Iran: A Case Study in West Esfahan

Migration of young people from rural areas reduces the rural development goals and increase social and economic problems in cities. This is an analysis of the causes of rural-urban migration from Esfahan Mountainous areas and guidelines for reducing migration from villages. Data were obtained using mixed methods approach comprising questionnaire surveys and key informant interviews. Study population are residents of 28 villages from Fereidan and Fereidunshahr counties. The population are 6300 people, who have migrated from these two counties. 362 persons were selected Using Cochran formula, as the sample size. Then, analysis was performed using SPSS v. 20 software. The study revealed that poverty, lack of jobs, insufficient educational facilities, education in the city, lack of public transportation systems, unsuitable mountain Road, cold weather , shortage of doctors, hospitals and health facilities are main factors of rural-urban migration from iran Mountainous areas. So It is recommended to eliminate the problems mentioned to reduce the rate of rural-urban migration for the rural residents

Effect of pretension on the mechanical behaviour of bolted rock

ABSTRACT: A stepwise pull-and-shear test (SPST) scheme that numerically analyses the mechanical behaviour of bolted rock joints subjected to simultaneous pull-shear loading. The SPST scheme allows us to identify the optimum pretension stress magnitude at which the bolting system exhibits its ultimate shear capacity. The micro-mechanical properties of grout and bolt-grout interface were calibrated against the laboratory data. The micro-mechanical parameters of rock were calibrated against the laboratory data of coal and shale, and the micro-mechanical properties of rock joint interface were identified by reproducing the laboratory behaviour of coal-shale interface under the direct shear test. Then, the SPST scheme was employed to study the effect of pretension stress magnitude on the macroscopic behaviour of bolted coal. The numerical results revealed that at yield pretension stress magnitude (pull-out test) the rock bolting system could exhibit its ultimate shear performance

Tunability of terahertz random lasers with temperature based on superconducting materials

We theoretically demonstrate the tunabiltiy of terahertz random lasers composed of high temperature superconductorYBCO and ruby layers as active medium. The considered system is a one-dimensional disordered medium made of ruby grain and YBCO. Finite-difference time domain method is used to calculate the emission spectrum and spatial distribution of electric field at different temperatures. Our numerical results reveal that the superconductor based random lasers exhibit large temperature tunability in the terahertz domain. The emission spectrum is significantly temperature dependent, the number of lasing modes and their intensities increase with decreasing temperature. Also, we make some discussion to explain the reason for the observed tunability and the effect of temperature variation on the spatial distribution of the electric field in the disordered active medium

PSEUDO-RC-INJECTIVE MODULES

The main purpose of this work is to introduce and study the concept of pseudo-rc-injective module which is a proper generalization of rc-injective and pseudo-injective modules. Numerous properties and characterizations have been obtained. Some known results on pseudo-injective and rc-injective modules generalized to pseudo-rc-injective. Rationally extending modules and semisimple modules have been characterized in terms of pseud-rc-injective modules. We explain the relationships of pseudo-rc-injective with some notions such as Co-Hopfian , directly finite modules.&nbsp

Short-Term Effects of Glutamine Supplementation on Levels of Blood Lactate and Fatigue Index in Male Elite Swimmers

Food supplementations are public assistance for a variety of championships sports. Competitive and recreational athletes use the nutritional supplements to improve their performance in a long time. In this context, there is lack of information about whether glutamine supplementation has the potential to help improve the muscle recovery after a period of intense aerobic exercise to exhaustion. This study aimed to assess short-term effect of glutamine supplementation on the levels of lactate and fatigue index in male elite swimmers.  Research method was mid-experimental and research design was a pretest-posttest with control group that was administered as double-blind. Twenty swimmers with age range of 26-18 years were selected based on convenient sampling. Then, based on swimming record results of 50 and 100 m freestyle breasts  were randomly divided into glutamine and swimming training group (n = 10) or placebo and exercise swimming group (n=10 ). Then the glutamine was given to supplementation group and the placebo was given to the control group, both groups began to swim for 4 weeks. Studied variables including lactate levels, fatigue and athletic performance index were measured before and after the study.  The results showed that use of glutamine amino acids led to a significant reduction in the fatigue index and produced lactate in the supplementation group compared to the placebo group. The time of athletes' performance wasn’t significantly increased.  The results showed the glutamine supplementation in areas such as swimming where the athlete must take part in a day in several competition, has a significant impact on the reduction of blood lactate concentration and more endurance of athletes than accumulation of lactic acid and reduction of swimming athletes fatigue index . However, more research is needed in this area

Short-Term Effects of Glutamine Supplementation on Levels of Blood Lactate and Fatigue Index in Male Elite Swimmers

Food supplementations are public assistance for a variety of championships sports. Competitive and recreational athletes use the nutritional supplements to improve their performance in a long time. In this context, there is lack of information about whether glutamine supplementation has the potential to help improve the muscle recovery after a period of intense aerobic exercise to exhaustion. This study aimed to assess short-term effect of glutamine supplementation on the levels of lactate and fatigue index in male elite swimmers.  Research method was mid-experimental and research design was a pretest-posttest with control group that was administered as double-blind. Twenty swimmers with age range of 26-18 years were selected based on convenient sampling. Then, based on swimming record results of 50 and 100 m freestyle breasts  were randomly divided into glutamine and swimming training group (n = 10) or placebo and exercise swimming group (n=10 ). Then the glutamine was given to supplementation group and the placebo was given to the control group, both groups began to swim for 4 weeks. Studied variables including lactate levels, fatigue and athletic performance index were measured before and after the study.  The results showed that use of glutamine amino acids led to a significant reduction in the fatigue index and produced lactate in the supplementation group compared to the placebo group. The time of athletes' performance wasn’t significantly increased.  The results showed the glutamine supplementation in areas such as swimming where the athlete must take part in a day in several competition, has a significant impact on the reduction of blood lactate concentration and more endurance of athletes than accumulation of lactic acid and reduction of swimming athletes fatigue index . However, more research is needed in this area