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The study of malathion on nitrosative stress in rat liver
Akram Ranjbar,Hajir Sifpanahi,Farshad Rostampour
Pajouhan Scientific Journal , 2013,
Abstract: Introduction: Organophosphorus compounds are the most important and most widely used insecticides and malathion is one of this toxins that has been used in the world widely. Oxidative stress and nitrosative stress are the new mechanisms of these compounds. The aim of this study was evaluate the effect of malathion on nitrotyrosins’ cosentration in rat liver.Material and Methods: In this experimental study 12 male wistar rats with 180-250grs were separated into case and control equal groups. Case group administrated 200mg/kg/day for a week and control group have normal salin at this course. Then rats’ livers were homogenized and biomarkers of nitrotyrosin were measured by ElIZA test in them. The statistical software used for this analysis was SPSS version 16 and P< 0.05 was considered as the minimum level of significance.Results: Mean of nitrotyrosins’ biomarker in liver tissue for case group were 0.265±0.094nmol/mg protein reported and the mean of nitrotyrosins’ biomarker in liver tissue for control group were 0.180±0.007nmol/mg protein reported, p= 0.051.Conclusion: The Difference between two groups is very near to level of significance and mean of case group is more than control group, thus we result that malathion increase nitrotyrosin level and increase nitrosative stress in liver rat.
On the Galois group of Generalized Laguerre Polynomials
Farshid Hajir
Mathematics , 2004,
Abstract: Using the theory of Newton Polygons, we formulate a simple criterion for the Galois group of a polynomial to be ``large.'' For a fixed $\alpha \in \Q - \Z_{<0}$, Filaseta and Lam have shown that the $n$th degree Generalized Laguerre Polynomial $L_n^{(\alpha)}(x) = \sum_{j=0}^n \binom{n+\alpha}{n-j}(-x)^j/j!$ is irreducible for all large enough $n$. We use our criterion to show that, under these conditions, the Galois group of $\La$ is either the alternating or symmetric group on $n$ letters, generalizing results of Schur for $\alpha=0,1$.
Algebraic properties of a family of Generalized Laguerre Polynomials
Farshid Hajir
Mathematics , 2004,
Abstract: We study the algebraic properties of Generalized Laguerre Polynomials for negative integral values of the parameter. For integers $r,n\geq 0$, we conjecture that $L_n^{(-1-n-r)}(x) = \sum_{j=0}^n \binom{n-j+r}{n-j}x^j/j!$ is a $\Q$-irreducible polynomial whose Galois group contains the alternating group on $n$ letters. That this is so for $r=n$ was conjectured in the 50's by Grosswald and proven recently by Filaseta and Trifonov. It follows from recent work of Hajir and Wong that the conjecture is true when $r$ is large with respect to $n\geq 5$. Here we verify it in three situations: i) when $n$ is large with respect to $r$, ii) when $r \leq 8$, and iii) when $n\leq 4$. The main tool is the theory of $p$-adic Newton Polygons.
Randomly Weighted Averages on Order Statistics  [PDF]
Homei Hajir, Hasanzadeh Leila, Mina Ghasemi
Applied Mathematics (AM) , 2013, DOI: 10.4236/am.2013.49181
Abstract:

We study a well-known problem concerning a random variable uniformly distributed between two independent random variables. Two different extensions, randomly weighted average on independent random variables and randomly weighted average on order statistics, have been introduced for this problem. For the second method, two-sided power random variables have been defined. By using classic method and power technical method, we study some properties for these random variables.

On the invariant factors of class groups in towers of number fields
Farshid Hajir,Christian Maire
Mathematics , 2015,
Abstract: For a finite abelian p-group A of rank d, we define its (logarithmic) mean exponent to be the base-p logarithm of the d-th root of its cardinality. We study the behavior of the mean exponent of p-class groups in towers of number fields. By combining techniques from group theory with the Tsfasman-Valdut generalization of the Brauer-Siegel Theorem, we construct infinite tamely ramified towers in which the mean exponent of class groups remains bounded. Several explicit examples with p=2 are given. We introduce an invariant M(G) attached to a finitely generated FAb pro-p group G which measures the asymptotic growth of the mean exponent of abelianizations of subgroups of index n with n going to infinity. When G=Gal(L/K), M(G) measures the asymptotic behavior of the mean exponent of class groups in L/K. We compare and contrast the behavior of this invariant in analytic versus non-analytic groups. We exploit the interplay of group-theoretical and number-theoretical perspectives on this invariant and explore some open questions that arise as a result, which may be of independent interest in group theory.
Extensions of number fields with wild ramification of bounded depth
Farshid Hajir,Christian Maire
Mathematics , 2001,
Abstract: We consider p-extensions of number fields such that the filtration of the Galois group by higher ramification groups is of prescribed finite length. We extend well-known properties of tame extensions to this more general setting; for instance, we show that these towers, when infinite, are ``asymptotically good'' (an explicit bound for the root discriminant is given). We study the difficult problem of bounding the relation-rank of the Galois groups in question. Results of Gordeev and Wingberg imply that the relation-rank can tend to infinity when the set of ramified primes is fixed but the length of the ramification filtration becomes large. We show that all p-adic representations of these Galois groups are potentially semistable; thus, a conjecture of Fontaine and Mazur on the structure of tamely ramified Galois p-extensions extends to our case. Further evidence in support of this conjecture is presented.
Specializations of one-parameter families of polynomials
Farshid Hajir,Siman Wong
Mathematics , 2004,
Abstract: Let K be a number field, and let lambda(x,t)\in K[x, t] be irreducible over K(t). Using algebraic geometry and group theory, we study the set of alpha\in K for which the specialized polynomial lambda(x,alpha) is K-reducible. We apply this to show that for any fixed n>=10 and for any number field K, all but finitely many K-specializations of the degree n generalized Laguerre polynomial are K-irreducible and have Galois group S_n. In conjunction with the theory of complex multiplication, we also show that for any K and for any n>=53, all but finitely many of the K-specializations of the modular equation Phi_n(x, t) are K-irreducible and have Galois group containing PSL_2(Z/n).
Algebraic Methods of Classifying Directed Graphical Models
Hajir Roozbehani,Yury Polyanskiy
Statistics , 2014,
Abstract: Directed acyclic graphical models (DAGs) are often used to describe common structural properties in a family of probability distributions. This paper addresses the question of classifying DAGs up to an isomorphism. By considering Gaussian densities, the question reduces to verifying equality of certain algebraic varieties. A question of computing equations for these varieties has been previously raised in the literature. Here it is shown that the most natural method adds spurious components with singular principal minors, proving a conjecture of Sullivant. This characterization is used to establish an algebraic criterion for isomorphism, and to provide a randomized algorithm for checking that criterion. Results are applied to produce a list of the isomorphism classes of tree models on 4,5, and 6 nodes. Finally, some evidence is provided to show that projectivized DAG varieties contain useful information in the sense that their relative embedding is closely related to efficient inference.
Effect of Changing Solvents on Poly(-Caprolactone) Nanofibrous Webs Morphology
A. Gholipour Kanani,S. Hajir Bahrami
Journal of Nanomaterials , 2011, DOI: 10.1155/2011/724153
Abstract: Polycaprolactone nanofibers were prepared using five different solvents (glacial acetic acid, 90% acetic acid, methylene chloride/DMF 4/1, glacial formic acid, and formic acid/acetone 4/1) by electrospinning process. The effect of solution concentrations (5%, 10%, 15% and 20%) and applied voltages during spinning (10 KV to 20 KV) on the nanofibers formation, morphology, and structure were investigated. SEM micrographs showed successful production of PCL nanofibers with different solvents. With increasing the polymer concentration, the average diameter of nanofibers increases. In glacial acetic acid solvent, above 15% concentration bimodal web without beads was obtained. In MC/DMF beads was observed only at 5% solution concentration. However, in glacial formic acid a uniform web without beads were obtained above 10% and the nanofibers were brittle. In formic acid/acetone solution the PCL web formed showed lots of beads along with fine fibers. Increasing applied voltage resulted in fibers with larger diameter.
Carotid Artery Wall Motion Estimation from Consecutive Ultrasonic Images: Comparison between Block-Matching and Maximum-Gradient Algorithms
Effat Soleimani,Manijhe Mokhtari Dizaji,Hajir Saberi
Journal of Tehran University Heart Center , 2011,
Abstract: Background: Radial movement of the arterial wall is a well-known indicator of the mechanical properties of arteries in arterial disease examinations. In the present study, two different motion estimation methods, based on the block-matching and maximum-gradient algorithms, were examined to extract the radial displacement of the carotid artery wall.Methods: Each program was separately implemented to the same axial consecutive ultrasound images of the carotid artery of 10 healthy men, and the radial displacement waveform of this artery was extracted during two cardiac cycles. The results of the two methods were compared using the linear regression and Bland-Altman statistical analyses. The maximum and mean displacements traced by the block-matching algorithm were compared with the same parameters traced by the maximum-gradient algorithm. The frame numbers in which the maximum displacement of the wall occurred were compared too.Results: There were no significant differences between the maximum and the mean displacements traced by the blockmatching algorithm and the same parameters traced by the maximum-gradient algorithm according to the pair t-test analysis (p value > 0.05). There was a significant correlation between the radial movement of the common carotid artery measured with the block-matching and maximum-gradient methods (with a correlation coefficient of 0.89 and p value < 0.05). The Bland-Altman analysis results confirmed a good agreement between the two methods in measuring the radial movement,with a mean difference and limits of agreement of 0.044 ± 0.038. The results showed that both methods found the maximum displacement occurring in the same frame.Conclusion: Both block-matching and maximum-gradient algorithms can be used to extract the radial displacement of the carotid artery wall and in addition, with respect to the pixel size as error, the same results can be obtained.
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