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The effects of initial spacing layout on some allometric characteristics of 12-year-old Quercus castaneifolia trees grown in Central Mazandaran, north of Iran were examined. Trees were planted in 5 different layouts (1×1, 1.5×1.5, 2×2.5, 2×3 and 4×4 m). Tree height, diameter at breast height, natural pruning height and the survival of trees were recorded in each sample plot. Tree basal area and H/D ratio and standing volume were calculated for all trees. The results of statistical analysis showed that increasing in spacing level from 1×1 to 4×4 significantly increased the average diameter at breast height from 6.93 to 12.42 cm and survival from 53% to 85%. The average tree basal area per ha decreased from 19.98 m^2 ha^-1 to 6.43 m^2 ha^-1 and H/D ratio from 151 to 77 when the distance between trees increased from 1 × 1 to 4 × 4 m. but spacing regime had no significant effect on tree height and natural pruning height. It can be concluded that on the basis of standing volume, H/D ratio and survival rate, the best plantation spacing in this research station was 2 m × 3 m. Statistically, about 95% of the changes in sediment yield was due to the effect of increased dry land farming area in the basin (R^2= 0.95, α < 0.05).

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Considering an elastohydrodynamic lubrication line contact, this study investigates the tribo-dynamic effects introduced by surface waviness. These waviness profiles are inevitable during various machining processes, such as grinding, and are on a larger scale than roughness. The waviness feature excites vibratory motions of contact bodies, and influences the lubrication performance through dynamic contact force and periodic squeezing. In this work, a tribo-dynamic formulation is implemented to examine such impact on film thickness, contact pressure, friction, and movement of the contact components. Owing to the presence of subharmonics, waviness introduced tribo-dynamic behavior cannot be eliminated within the adopted operating speed range. However, it is shown to be feasible to implement engineered waviness profile for lubrication performance improvement, providing a new and effective technique for friction/power-loss reduction, for instance. [ABSTRACT FROM AUTHOR]

Background and Objective: Anterior cruciate ligament (ACL) tear is one of the most common injuries at knee joint. This study was done to evalute the effect of reconstruction surgery on hamstring reflex in patients with ACL tear. Materials and Methods: In this Quasi- experimental study, 30 patients (16 males, 14 females) with ACL tear, with mean age of 26.52±8.72 years old were recruited during 2007. Patients were selected in a non probability sampling manner. The Kinsiological Electromyography and trauma mechanism were used for testing the hamstring reflex. Muscle activity were measured as a dependent variable. Data were analyzed with Paired T-Test, ICC, SEM and K-S tests. Results: Hamstring reflex in affected knee and after reconstruction surgery was 73.25±3.22 and 47.35±3.85, respectively. This difference was significant (P

Background and Objective: Several studies have demonstrated the importance of a coordinated, synchronized action of a scapular and glenohumeral muscles. Minimal alteration in performance and coordination of these muscles have the potential to lead to joint dysfunction. The impingement syndrome is the most common diagnosis of shoulder pain. The purpose of this study was to determine whether strength deficits could be detected in patients with shoulder impingement. Materials and Methods: This case – control study was done on 15 patients with impingement syndrome and 15 healthy matched persons by nonprobability sampling in Tehran, Iran during 2008. Strength of glenohumeral and scapulothoracic muscles was tested with a hand held dynamometer. Independent and paired t-test were used to statistically analyze between and within groups differences. Results: Compared to non impaired subjects, those with impingement syndrome demonstrated a significantly lower strength of shoulder muscles (P

It was argued that the vacuum energy of the Veneziano ghost field of QCD, in a time-dependent background, can be written in the general form, H + O([H.sup.2]), where H is the Hubble parameter. Based on this, a phenomenological dark energy model whose energy density is of the form ρ = αH + β[H.sup.2] was recently proposed to explain the dark energy dominated universe. In this paper, we investigate this generalized ghost dark energy model in the setup of Brans-Dicke cosmology. We study the cosmological implications of this model. In particular, we obtain the equation of state, the deceleration parameters, and a differential equation governing the evolution of this dark energy model. It is shown that the equation of state parameter of the generalized ghost dark energy can cross the phantom line ([w.sub.D] = -1) in some range of the parameters spaces. PACS Nos.: 95.36.+X, 98.80.-k, 98.80.Jk. Il a ete suggere que l'energie du vide du champ CDQfantome de Veneziano, avec un fond dependant du temps, peut etre ecrite sous la forme generale H + O([H.sup.2]), ou H est la constante de Hubble. Sur cette base, un modele phenomenologique a recemment ete propose pour une energie sombre dont la densite d'energie a la forme ρ = αH + β[H.sup.2], afin d'expliquer un univers domine par l'energie sombre. Ici, nous etudions ce modele generalise d'energie sombre fantome dans le cadre de la cosmologie de Brans-Dicke et sondons ses implications cosmologiques. En particulier, nous obtenons l'equation d'etat, les parametres de deceleration et une equation differentielle gouvernant l'evolution de ce modele d'energie sombre. Nous montrons que le parametre de l'equation d'etat de l'energie sombre generalisee peut croiser la ligne du fantome ([w.sub.D] = -1) pour certain domaine de valeur des parametres d'espace. [Traduit par la Redaction], 1. Introduction Nowadays, it is a general belief that our Universe is currently experiencing a phase of accelerated expansion. Various cosmological observations confirm this acceleration. The first significant evidence was [...]

In this paper, we study the cosmic age problem in holographic (HDE) and generalized ghost dark energy (GGDE) models. To this end, we consider these two models in presence of non-linear interaction terms for three special cases, presented in the literature. We explain the impacts of the mentioned interaction terms on the cosmic age during the evolution of the Universe. There are many old cosmic objects (OCOs) which their evaluated age is not consistent with that of dark energy models. Here, we confine our attention on five cases of more known OCOs at different redshift. The purpose is to constrain the DE models, using the age of these OCOs. We obtain boundary values for free parameters of the HDE (b 2 and c) using the age test and find that, such non-linear interactions can alleviate the age problem in spite of the linear one. The GGDE was already constrained using a joint analysis of data sets SHBC. We find a new bound for ξ that wasn't predicted via SHBC analysis. Beside, we find that the GGDE can completely alleviate the cosmic age problem. [ABSTRACT FROM AUTHOR]

Drivers encounter a variety of outdoor advertising including fixed and wrap advertisement and large amounts of information and data in different locations, which can sometimes confuse the audience due to congestion, accumulation, and non-compliance with the standards and diversity of concepts. Fully understanding how small distractions can influence the ability to drive could prevent a serious accident. Despite the enormous amount of effort has been devoted to evaluating the impact of fix advertising on traffic safety, the importance of investing wrap advertisements seems to be disregarded. Therefore, the present study seeks firstly to compare the importance of distraction caused by wrap advertisement with other parameters affecting drivers' awareness, then to find out which aspects of wrap advertisement may distract drivers while driving. To address this objective, at first, a questionnaire-based accidents database was prepared regarding those occurred because of distraction, and then the weight of distraction caused by wrap advertisement was identified using AHP. Subsequently, accidents that occurred because of this specific issue were modeled using the discrete choice technique. The results showed that in contrast with the prevailing opinion of drivers, the probability of distraction while driving caused by wrap advertisement is relatively high which can be considered as an alarming issue. Moreover, according to the results of discrete choice modeling, drivers with different characteristics, such as age or gender can be affected by wrap advertisement in different ways. [ABSTRACT FROM AUTHOR]