Agent-based models are often used in order to describe dynamic economic environments with high levels of complexity. Through this type of models, micro-agents, such as individual consumers, can be analysed and understood without calling upon generalisations. This paper reviews the current state of the art in this area. We focus on comprehensive models that take into account and attempt to represent the peculiarities of consumer behaviour. The topics of agent learning in particular and learning algorithms in general are also emphasized, as we believe that learning is a sine qua non condition for the proper representation of medium and long term behavioural patterns.
Superlift converter is a type of DC-DC converter in which the output voltage increases in a very high progressive range. This paper focuses on deriving a dynamic model for a Negative Output Elementary Superlift Luo Converter (NOESLLC) with its performance parameter analysis. Moreover, this paper depicts the modeling and analysis of NOESLLC which converts a positive source voltage into a negative load voltage. The dynamic analysis of a converter highly helps in predicting the stability, reduction of ripple in the supply, EMI filter design compatibility thereby making the converter design economical. With the dynamic characteristics representation, the energy factor parameters of NOESLLC have also been computed which portrays the importance of system recovery from interference and also aids in making the design simple.A prototype of NOESLLC converter is also built to validate the simulation results.
Liquid level control in spherical geometry is used in process industry for safe storage of liquid and has drawn more attention as it is quite non-linear in nature. The entire tank is divided into four regions along liquid height for which mathematical models are developed separately. PI fuzzy controller is synthesized using multimodel approach and a novel method for autotuning of PI fuzzy controller for liquid level of spherical tank system is developed in this work where ultimate properties are modeled as function of system parameters. On comparing the performances of the PI fuzzy logic controller (PIFLC) with that of autotuned PI FLC the latter shows better results in several objective functions such as ISE, IAE. From simulation results it is inferred that the autotuning procedure reduces the number of fuzzy rules and thereby decreases the computational time. The robust performance of the controller is proved through real time results.
Abstract\nBackground: Formocresol as a pulp fixative agent has undesirable effects. The other medicaments as alternative for formocresol are currently under investigation and none of which is proved yet. \nAim: The purpose of this study was to compare the radiographical and histological findings after using formocresol and Elaeagnus angustifolia in pulpotomized dogs primary teeth.\nDesign: The pulpotomies were performed on 20 intact primary canines in 5 dogs and 5 intact primary third incisors were as the control group. The teeth were treated using either a conventional formocresol or Elaeagnus angustifolia. Before the pulpotomy and 60 days after the pulpotomy procedure, the teeth were evaluated for radiographical and histological findings. Data were analyzed by SPSS v.18, by Wilcoxon Rank-Sum test (for the ordinal variables) and McNemmar test (For the binary variables). \nResults: After 60 days of follow up, all of the samples from both groups had no clinical pathologic conditions. Whereas, internal resorbtion was only detectable in Formocresol group in the radiographic images and histological sections. The difference between the two groups was statistically significant in the radiographic images(P<0.05) but it was not significant in the histological sections(P>0.05). In the histological view, the level of Inflammation as well as the amount of tissue necrosis were not significantly different between the two groups (P>0.05). Whereas, the level of vascularisation was significantly different between the two groups (P<0.05). \nConclusion: The results showed that Elaeagnus angustifolia extract can be an acceptable alternative for formocresol in pulpotomy of deciduous teeth. Further studies in human volunteers are suggested.\nKey words: Deciduous teeth, Elaeagnus angustifolia, Formocresol, Pulpotomy.
Teaching of organic chemistry is one of the most important issues in chemistry education. University students’ achievements in organic chemistry depend on general chemistry achievements, high school chemistry course performance, test scores, and cognitive variables such as spatial visual performance. In addition, non-cognitive variables such as anxiety levels also have an impact on students’ organic chemistry achievements. The present study reports the development and score validation of an instrument for measuring organic chemistry anxieties students experience in university organic chemistry lessons. Factor analytic evidence from a sample (n = 340) of university organic chemistry students shows the Organic Chemistry Anxiety Scale (O-CAS) measures three constructs: (a) writing bond type of organic compounds, formulas and naming them, (b) writing the types of organic compounds and their isomers, and (c) writing the reaction mechanism of organic compounds. Additional analyses with a second sample (n = 297) show that scores on these anxiety constructs are internally consistent, with Cronbach’s alphas ranging from 0.89 to 0.94. The O-CAS can be used as a valid and reliable instrument in education and psychology.
The aim of the research was to analyse the influence of additive Kaolin E 559 to swine meat production and quality. Two groups of Lithuanian White pigs offspring were formed by the principle of analogue – the control and the experimental group (21 and 24 pigs). The offspring from experimental group got additive Kaolin E 559 since the 6th day of age. \nWhen, reached 190 days of age was carried out on experimental and control groups of swine control slaughter.\nNatural additive Kaolin E 559 increased makeweight of the swine offspring by 10.6 pct (p<0.05) during the period from 6th to 190th day of age.\nThe outcome of carcass meat of the experimental group was identified to be 1.43 pct bigger than of control group. After performing a research on chemical indexes of meats‘ quality, we have identified that the experimental group had a bigger amount of proteins by 0.38 pct. (p>0.05), fat - by 0.19 pct. (p>0.05) and ashes by 0.06 pct. (p<0.05) than the control group.\nThe experimental group was identified to have a milder meat, besides that this group distinguished for having less cooking loss (p>0.05) of meat. Moreover, this groups‘ meat distinguished for having a better water holding capacity (p>0.05).
5-Acetyl-4-methyl-2-(4-nitrophenyl)pyrimidin-6(1H)-thione (3) was reacted with halo compounds in aqueous ethanolic potassium carbonate solution to give S-alkyl derivatives 4 and 5a-d. Treatment of compounds 3 with ethyl bromoacetate, mono-chloroacetic acid, phencyl bromide and chloroacetamide in sodium ethoxide solution afforded the corresponding thieno[2,3-d]-pyrimidine derivatives(6a-d). Thiopyrano[2,3-d]pyrimidine derivatives (7a,b) and isothiazolo[5,4-d]pyrimidine (8) were prepared via reaction of 3 with aromatic aldehydes and NaOCl, respectively. Chlorination of 3 afforded 4-chloropyrimidine derivative (9) which was cyclized to the corresponding pyrazolo[3,4-d]pyrimidine (10), pyrimido[4,5-d]pyrimidine (11) and pyrrolo[2,3-d]pyrimidine derivatives (12). Antimicrobial activity of the prepared compounds was tested against bacteria and fungi organisms. Among them, pyrimido[4,5-d]pyrimidine-2-amine (11) posses the highest microbial activity.
In the studies conducted in 2011 the content of lead and cadmium in\naboveground parts of plants growing adjacent the route S2 (Siedlce road) was analyzed. The\nfollowing plants as : Taraxacum spec., Achillea millefolium L, Rumex acetosa L., Vicia L.\ncracca were tested. Plant samples were taken at distances 1, 5, 10 and 15 m from the edge of\nthe road. The average content of lead in plants was 2.41 mg∙ kg-1, and 0.242 mg∙ kg-1of\ncadmium. The highest average content of the analyzed elements accumulated Achillea\nmillefolium plants, respectively, Pb - 3.24 Cd - 0.324 mg ∙kg -1, while the smallest one -\nRumex acetosa plants: Pb - 1.77 and Cd - 0,175 mg∙ kg -1. Lead content in plant samples from\n1 to 10 m did not differ significantly and amounted : 2.64, 2.60, 2.41 mg∙ kg-1. Samples\ncollected at a distance of 15 m had the lead content in plant samples significantly lower than\non the other distance - 2.00 mg∙ kg -1. Cadmium content in plant samples was depended on\ntheir distance from the edge of the road and amounted respectively: 0.540, 0.133, 0.143 and\n0.190 mg∙ kg-1. There was no significant, negative depending on the cadmium content in\nplants on the distance from the road. Changes in the lead content in samples of Taraxacum\nspec. and Achillea millefolium presented more differently than for other species. The highest\ncontent cadmium, in depend on the plant species, were found in the samples collected\ndirectly (1 m) from the roadway line. Further samples were characterized by a lower content\nof this element, and minimum of this effect was found at a distance of 10 m. About the\nsimilarity of cadmium phenomenon bioaccumulation by tested plant species provides multiple\nregression equations course, determining the impact of distance from the roadway on the\ncadmium content in plants. The obtained results of cadmium and lead content does not\nexceed the values specified as limits for agricultural use of this pastures.
In this treatise, the performance of double space time transmit diversity (DSTTD) multi-carrier (MC) - interleave division multiple access (IDMA) system for downlink (DL) communications is evaluated. DSTTD is constructed with two space-time Block-code (STBC) units at the base station (BS) and at the mobile station (MS), minimum mean square error (MMSE) based maximum a-posteriori (MAP) algorithm is employed for symbol detection. The basic difference between IDMA and conventional code division multiple access (CDMA) is that in IDMA, user specific interleaving pattern are used as user-separation whereas in CDMA, orthogonal spreading sequence is used as user specific. The MC modulation is realized by IFFT block at the BS and FFT block at each MS. Further turbo coded system has been considered to mitigate the effects of inter-symbol-interference (ISI) and multiple access interference. Furthermore, the performance of DSTTD MC-IDMA for turbo coded system considering realistic channel model based on Standard University Interim (SUI) specifications and long-term evolution (LTE) is investigated. It is observed through the computer simulation results that DSTTD MC-IDMA can provide better performance in terms of achievable bit error rate (BER) by invoking iterative decoding algorithm at the mobile stations.
Nitric oxide (NO) and salicylic acid (SA) are well established as signaling and ubiquitous bioactive molecules that play a key role in tolerance of plant to abiotic stress by regulating the various plant cellular mechanisms. Therefore, the present experiment was conducted to study the interactive effect of NO and/or SA in tolerance of wheat (Triticum aestivum L. cv. Samma) under cadmium (Cd) stress. The results indicated that Plants grown in Cd-containing medium exhibited reduced growth characteristics ( plant height, fresh weight, dry weight and leaf area), carbonic anhydrase activity and content of essential nutrients [nitrogen (N), phosphorus (P) and potassium (K)] nutrients and chlorophyll (Chl) a and b by enhancing MDA and Cd accumulation. However, combined application of NO and SA was more effective in suppression of deleterious effect of Cd stress by inducing the activities of enzymes [carbonic anhydrase (CA), superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT)] and accumulation of osmoprotectant (Pro) and by maintaining nutrients homeostasis, leading to the reduction of MDA accumulation and improvement of photosynthetic pigments (Chl a and Chl b) resulted in a better plant growth performance under Cd stress. The present study revealed that application of both NO and SA together improved the plant growth and development by reducing formation of reactive oxygen species by improving antioxidant enzymes and CA activity and balance supply of nutrients.
Purpose: The ability to perform some instrumental procedures may differ among women and men because for example of difference in strength. We investigated the effectiveness of airway management between genders during a manikin simulation of 3 intubation scenarios. \nMethods: A total number of 200 of 3rd year of School for Paramedics (50% women), performed instrumental airway management on a manikin simulator using Macintosh blade laryngoscope MCL, TruView Evo2 and AirTraq. The time to complete procedure, success rate and pressure created on tongue of manikin was recorded. All participants were evaluated for muscle strength. \nResults: The women had significantly smaller muscle strength than men. In the intubation scenarios using standard MCL laryngoscope and Truview Evo2, men intubated faster than women, but women were more precise – higher success ratio. The pressure applied to the tongue with laryngoscopes by women was lower than that applied by men. In case of optical laryngoscope – AirTraq the differences between genders were the smallest.\nConclusion: In a airway management scenarios, although women have smaller muscle strength than men, they are more precise, but slower. However, for the clinical efficacy of airway management procedure the differences between gender groups were not important.
Atmospheric dispersion characterizes become in time and space of a set of particles (aerosols, gases, dust) released into the atmosphere. In order to identify the physical mechanisms involved in the atmospheric dispersion of a substance, we performed in this study measures the rate of air flow in situ in the presence of obstacles. The effect of a Gaussian hill on the speed at different heights is highlighted. Numerical modeling has potential advantages over the physical techniques such as in situ tests or small scale (quick study and opportunity to consider a large number of situations). The numerical dispersion models are characterized by their complexity. Process and analyze such systems by conventional mathematical methods is very difficult if not even some times impossible. In this work, we applied an artificial intelligence techniques especially fuzzy logic inference system for modelling the wind dispersion speed before, on, and after the gaussian hill. The work was carried out in the atmospheric wind tunnel of fluids mechanic laboratory of the ECLyon (France). The initial data used are measured variables (Position, surface condition, preset wind speed and different altitudes). The air velocity is considered as an output.
The purpose of this study is to determine the metaphors that the elementary school 4. grade students have about the concept of game. This study is applied for 645 elementary school students studying at 4. grade for in 1. term of 2012-2013 academic year in 8 elementary schools within the boundaries of the districts of province of Sakarya. This study is applied from the data that is obtained from a total of 378 students, consits of 204 girls and 174 boys. This study consists of transferring and extracting the data obtained from analysis of the documents by electronic media, the classification of metaphors and reasons, developing conceptual categories, validity and reliability studies and quantitative data analysis. As a result of this study the 10 conceptual categories that are created are arranged according to their repetition frequency as follows: games as pleasurable, game as activity, game as instructive, game as must-have, game as person, game as the object, game as location, game as food, game as technology and game as an institution. Teachers can make use of this information when they are selecting games for the students during training phase.
In this study, the corrosion behaviors of AISI 420 and AISI 5120 steels borided in Ekabor-II powder at a temperature of 950 ºC for 5 h were investigated in a 4% M HCI acid solution. The properties of the boride layer were evaluated by optical microscopy, X-ray diffraction, the micro-Vickers hardness tester. X-ray diffraction analysis of the boride layers on the surface of the steels revealed the existence of FeB, Fe2B and CrB compounds. The boride layer thickness on the surface of the AISI 420 and AISI 5120 steels was found to be 50.62 μm and 148.74 μm, respectively depending on the chemical composition of the substrates. The hardness of the boride compounds formed on the surface of the AISI 420 and AISI 5120 steels ranged from 1854 to 2147 HV0,05 and 1498 to 1892 HV0,05 respectively, whereas the Vickers hardness values of the untreated steels AISI 420 and AISI 5120 were 340 HV0,05 and 224 HV0,05, respectively. The corrosion resistance of the borided steels was higher compared with that of the unborided steels. The borided steels increased the corrosion resistances of the steels 6–8- fold.
The main objective of this paper is the determination of the protection lost sales (i.e., the probability of not going out of stock) and the potential lost sales (i.e., the unsatisfied demand) when the lead time demand has the generalized beta II distribution(GB2). The method of maximum likelihood is used for estimating the model parameters. The protection lost sales, the mean and the variance of potential lost sales for GB2 and some of its special cases are estimated. Finally some conclusions are presented. \nKeywords: Beta and incomplete beta functions; Protection lost sales; Mean and the variance of potential lost sales; Lead time demand; Generalized beta II distribution.
Asymptotic distribution of U-statistics of the distribution leads to two groups; normal distribution and the other one is a linear combination of independent random variables chi-square with one degree of freedom. In the situation of discrete random variable takes three cases, asymptotic distribution of estimators of central moments is consistent with the distribution of the second kind. Alternative methods that have been raised in the Satterthwaite\'s problem, we want to approximate the asymptotic distribution of these estimators offer.
In this research; teachers’ attitudes, perceptions, intentions and behaviors about taking the advantage of cartoons in teaching were examined with respect to Technology Acceptance Model (TAM). The data were gathered from 271 teachers, who live in different cities in Turkey. The data were analyzed by structural equation modeling and the findings were discussed.
In this study,based on the theories of Janet.S.Chafetz,Pierre Bourdieu and Lawrence Harrison,the effect of the above mentioned independent variables on the dependant variable of gender inequality(inequality of women and their husbands in capital on cultural, social, ecoomic and symbolic assets)was measured.This was done in 2012,amongst 455 married women in seven regions of Tehran(upper,middle,lower class),using survey techniques and questionnaires. \nThe survey results show that there is a significant correlation between the variable rates of religiosity,level of women’s education,the family income and the gender inequality.(With the first variable opposite direction and the next two parallel directions).Although the next two other independent variables including the tendency of patriarchy ideology and the gender socialization have correlation with gender inequality but more or less they both have interface role. \n\nBy increasing tendency to patriarchy ideology,religion and gender socialisation,gender inequality also increases.On the contrary,by increasing the level of female education and family income,gender inequality is reduced.\n\nKeywords: gender injustice, gender inequality, gender socialisation, patriarchal ideology, religiosity
In this paper, a particular family of meromorphic functions, which share a function set is considered. By the famous Zalcman-Pang lemma, we derive a sufficient condition for the normality of this particular meromorphic functions family.
The present paper proposes a new approach for the analysis of dynamics in complex fluids. The dynamics of fluid particles takes place on continuous but non-differentiable curves. This idea is the starting point of our paper. Consequently, standard properties of complex fluid such as patterns generation through self-organisation, oscillations through self-similarity, etc. are controlled through non-differentiability of motion curves.
In this paper we proposed Neurocomputational based simple approach for the design of a triangular microstrip antenna as forward side and analysis as reverse side of problem. Also this paper presents a relative performance of the different variants of back propagation training algorithms for estimating side length and feed position of triangular microstrip antenna with particular attention paid to the speed of computation and accuracy achieved. The Method of moments (MoM) based IE3D software used to generate data dictionary for training and validation set of Neurocomputational model. The main advantage of using ANN is that a properly trained neural network completely bypasses the complex iterative process for the design and analysis of this antenna. Results obtained by using artificial neural networks were in very good agreement with the simulated results.
The Farrow structure implementation complexity grows rapidly as the bandwidth approaches the full bandwidth but it can be used for efficient realization of adjustable fractional-delay finite-length impulse response (FIR) filters. A multirate approach can be used to reduce\nthe complexity. Using a fixed half-band linear- phase FIR\nfilter the input signal is first interpolated by a factor of two. After that, the real fractional-delay filtering occurs. In order to retain the original input/output\nsampling rate down sampling is done. By doing this, the\nbandwidth of the fractional-delay filter is r e d u c e d t ohalf of the overall bandwidth.The overall complexity can be reduced because the complexity of half- band linear-phase FIR filter interpolators is low. T h e implementation details, design trade-offs, and comparisons using multiple constant mul- tiplication techniques when the filters are implemented, which realize a number of constant mul- tiplications with a\nminimum number of adders and subtracters are\npresented
This paper contains the simulation and experimental\nresults of a developed single-phase Thyristor Switched\nCapacitor (TSC), while the power factor at the fundamental frequency (displacement power factor) of an electrical system with distorted voltage is being compensated. The developed single-phase TSC can produce reactive capacitive power w i t h t h r e e d i f f er e nt values. The Thyristor Switched Capacitor\ncan c o mp e n s a t e inductive reactive power at the\nfundamental frequency, and it doesn’t cause voltage and\ncurrent transients when i t i s turned-on. B u t , it i s s e e nt h a t i n s i t u a t i o n s where the voltage i s d i s t o r t e d ,the TSC produces harmonic currents, which is detrimental to the electrical s yst em. The c a pac it or bank used in industries for power factor correction has the same problem in the distorted voltages.
The design of introduces a multi-mode transmulti- plexer (TMUX) structure capable of generating a great set of user-bandwidths and center frequencies. The structure utilizes fixed integer sampling rate conversion (SRC) blocks, Farrow- based variable interpolation and decimation structures, and variable frequency shifters. A main advantage of this TMUX is that it needs only one filter design beforehand. Specifically, the filters in the fixed integer SRC blocks as well as the subfilters of the Farrow structure are designed only once. Then, all possible combinations of bandwidths and center frequencies are obtained by properly adjusting the variable delay parameter of the Farrow-based filters and the variable parameters of the frequency shifters. The paper includes examples for demonstration. It also shows that, using the rational SRC equivalent of the Farrow- based filters, the TMUX can be described in terms of conventional multirate building blocks which may be useful in further analysis of the overall system.
The aim of the present study was to determine the prevalence and contamination level of C. perfringens in minced poultry and beef sold at retail market. The objectives of the present work were to investigate the presence and contamination level of Clostridium perfringens in poultry and beef minced beef by MPN (Most Probable Number) methods. A total of 100 samples, the raw minced poultry meat (n: 50), and minced beef (n: 50) were collected from various retail stores and butcher. Our results demonstrated that 61 of 100 saples (61%) were contaminated with between 3.0-20.0 MPN/g Cl. perfringens. 34 of 50 minced beef samples (68%), 27 out of 50 minced poultry meat samples (54%) were found to be contaminated with Cl. perfringens. Minced beef and poltry meat samples were detected to be contamination level of respectively average 4.9 MPN/g and 3,5 MPN/g. In our survey is observed that depending on the increasing air temperature Cl. perfringens was seen to increase in prevalence and contamination level and butchers more unfavorable hygienic conditions and rules than supermarket. The ubiquity of this bacterium, the sporeforming ability, the short generation times, the wide temperature range in which the organism grows, the ability to adapt and grow in different food environments, and the diseases caused, make this microorganism a significant health hazard. Thus, proper control strategies are required to reduce the number of disease cases and outbreaks frequently caused by this organism around the world.
The Variational Iteration Method (VIM) is applied to some systems of nonlinear PDEs. \n In this paper, we consider coupled higher- dimensional Burgers (Chd Bur) equations are \n We find both exact and numerical solutions, we compared the numerical solutions with corresponding analytical solutions
In industrial field, the automated visual inspection systems is applied effectively to identify the defects in \nvarious digital images. In this research work we have proposed a new defect detection algorithm based on \nlocal homogeneity and discrete cosine transform (DCT) to eliminate the texture elements in the digital \nimage by isolating the defected area. Firstly, the local homogeneity of each pixel is computed to construct a \nnew homogeneity image denoted as (H-image). Then a DCT transform, in order to extract features energy, \nis applied. After these energy are integrated by the Hotelling’s T-squared statistic and the defect blocks can \nbe determined by the multivariate statistical method. Finally, a simple thresholding method is applied to set \na threshold for distinguishing between defective areas and uniform regions. Simulations on different \ntextured images show good promising results. This new automatic defect detection method shows good \nperformance in comparison with other existing algorithms.
Encryption is an encoding process which is applied to different data patterns. It applies some reversible transforms to make it humanly unreadable except by someone who knows how to inverse the process. The complexity of the used algorithms is measured by the amount of time that the fastest computers take to break the encryption code and recover the plain text or original data. \nIn this paper, we introduce a combination of three encryption techniques based on random permutations, pixels intensity change and logic operator for a safer and more complicated process. Each of them is based either on a random basis or on a chaotic function. Passing through the three algorithms ensures irreproachable results. These techniques are entirely reversible and generate no data loss.
Adsorption kinetic study of C.I. reactive blue 19 onto cotton was carried out in SDS-CTAB reverse micelles. The data of adsorption kinetics were examined using pseudo first- and second-order kinetic models. It was found that the adsorption kinetics of dye on cotton with diffusion controlling follows the pseudo first-order kinetic model with an activation energy of 84.64 kJ/mol. The adsorption process was endothermic in nature through the thermodynamic parameters.
Assessing plant diversity in forest is an important issue in studying ecosystems and their conservation. In this study, the diversity of plant species in riparian forests of Maroon region were considered based on biodiversity indices. Seventy-nine plots (each included one 2 ×2 m micro plot) were sampled based on transects-quadrate method. Species and percent cover were identified in each plot for each species. The mean of biodiversity indices was assessed on each plot for data analysis and they were determined for different assemblages individually at different distance from river. Then, the indices were compared among the difference distances. Totally, 71 species belonging to 59 genera and 24 families were identified. The results indicated significance between indices of heterogeneity, richness and evenness of herbaceous species at different distances from the river and as distance from the river increased, the richness and heterogeneity increased and the evenness decreased. heterogeneity, richness and evenness indices of woody species showed no significance at different distances from the river but heterogeneity and richness is more on near the riparian areas.
The process of education is changing globally and locally. We have impresion that our staff is well educated and can find place in job market all over the world. We try to solve deficit of physiotherapists in Republic of Macedonia with opening of Studies with 3 and 4 years at four public universities. Aim of our investigation was to determinate the level of education compared with other countries in the world. Material and method: We have made one interview with 12 university professors, from 15 different countries from the world ( Italy, Germany, USA, UK, India, China, Ghana, Romania, Indonesia, Canada, Belgium, Macedonia, Albania, Ethiopia, Haiti, Madagascar, Brazil ) on 9 questions, with maximum point of 9, and minimum 0. The level of education was graded as low (0-2) points, middle (3-5) points, high middle (6-7) and high (8-9) points. Results: Our investigation is showing a high middle level of education in Macedonia (7). Discussion and conclusion: Educational system is involved according Bologna standard, ECTS in Macedonia, We have not physiotherapist with doctoral level of education for practical education of students. The interuniversity collaboration for is possible , but for better quality of practice is needed interuniversity exchange of students.
Three populations of cork oak Quercus suber in the Western forest of Tunisia grown under three different climatic environments were chosen for this study. A dendrochronological analysis was undertaken to identify the climatic parameters that influence the radial growth of cork oak trees. By crossdating series of rings, we could reconstruct the radial growth of these populations to the 20th century and analyze the possible existing relationships climate-rings. We calibrated a generic model of vegetation to estimate cork oak biomass growth and assess the impact of potential climate change scenarios on forest productivity. A strong effect of water stress on forest productivity was reached in the driest regions. The temperature also plays a role in the wettest areas.