modern research physics

---

Several experiments have been performed during the last few decades to evaluate the responses of plants to enhanced solar UV radiation (UV-R) that may occur because of stratospheric ozone depletion. The objective of this study was to evaluate the effects of UV radiation on some anatomical and ultrastructural aspects of pepper plants (Capsicum longum L) in the greenhouse. Pepper plants were grown in a uniform environment and after 35 days they were exposed to UV-A and UV-C radiation for 15 and 8 days, respectively. The results indicated that the changes in root growth was not significant but the growth of shoot decreased in UV-R exposed plants and this reduction was significant in UV-C exposed plants. Leaf area was also reduced in UV-R exposed plants and this reduction was significant in UV-C exposed plants. The root diameter was not affected under UV treatment, but the stem diameter and leaf thickness were significantly increased in both UV-A and UV-C treatments. The number and size of stomata were also increased in UV-R exposed plants. At the ultrastructural level, it was found that the thylakoids of chloroplast were dilated and starch reduction was observed. UV treatment resulted in the formation of crystalline inclusion in the peroxisomes of the mesophyll cells. Formation of these crystals may be due to the increased activity of catalase, which is an antioxidant enzyme. The study shows that pepper plants are sensitive to UV-R and this finding provides insight into the structural and ultrastructural changes during UV exposure, and indicates the sensitivity of these plants to UV-C more than UV-A radiation.

---

By using the Berwald connection, we show that there is a linear connection &nabla such that these are projectively equivalent and belong to the same projective structure on TM. We find a condition for the geodesics of the berwald connection under which &nabla is complete.

---

Anbaran inlier is located at the NW of Namin city. In the inlier Pre-Paleozoic roks surrounded by young Eosen and Cretaceouse rocks.To interpret the inlier deformation and its evolution model, geometry as well as kinematic characteristic its major structurs analysed for the first time. For the faults kinematic, indicator, such as slickenside, fault associated folds and S-C structure were used. The results of analysis show that the major structurs of inlier are the Anbaran and RF1 fault at its Norht and South margins.The high angle Anbaran and RF1 faults cause thrusting of the Pre-Paleozoic Biandor and Soltanieh formation in the core of inlier over the Eocen volcanic units and Cretaceouce limeston respectively.This resulted in development of a pop-up structure that form the present morphology of the region .The fault high angele dip, and deposition of Cretaceous sediments on its hanging wall provide evidence for the fault inversion.therefor the RF1 fault is considered as the inverted anbaran fault backthrust.

---

Determining the Optimal Complexity of Bipartite Access Structures

Abbas Cneraghi

Abstract

Keywords: Complexity, Secret Sharing Scheme, Access structure.



In a bipartite secret sharing scheme, the set of participants is divided into two parts, and all participants in each part play an equivalent role. The ideal bipartite access structures were characterized by Padro and Saez, but it is not known which is the optimal information rate of non ideal bipartite access structures. Determining the optimal complexity of general access structures is one of the major problems in secret sharing. We study this open problem restricted to the bipartite access structures, obtaining a new method to compute bounds on the optimal complexity. Namely, by using the connection between secret sharing schemes and polymatroids, we show a linear programming problem that determines, for each access structure, a lower bound on the complexity. Moreover, we show new optimal constructions for certain bipartite access structures.

---

Department of Chemistry, Takestan Branch, Islamic Azad University, Takestan, Iran High frequency sound wave, ultrasound, is widely used to facilitate chemical reactions, especially in the polymerization reactions.This paper reports a study which synthesized acrylic hydrogel in the presence of ultrasonic irradiation (20-kHz, power 80%, pulse 8) in a water/glycerol medium. Acrylic acid (AA) and acrylamide (AAm) were used as acrylic monomers, and methylene bisacrylamide (MBA) as the crosslinker. The experiments were performed at a constant temperature of 37 °C. It was found that hydrogel formation is faster in the presence of ultrasound than in its absence. In addition, FT-IR, UV-Vis, and SEM spectroscopy showed that the hydrogel synthesized ultrasonically has a higher swelling capacity and a more uniform and porous structure. It was also discovered that hydrogel formation speeds up at higher quantities of glycerol. However, an increase in crosslinker concentration proved ineffective although it changed the appearance of the hydrogel. The method proposed in this research can be used in the synthesis of biomedical materials and in the development of drug delivery systems.

---

In this study the predicted epitopes of C2-V3-C3 domains of gp120 of HIV-1, present in Iran, were compared to the epitopes of the homologous domains in subtypes A, B, C, D, E, F, G, H and I of this virus. Since epitopes are regions between the sequences with secondary structure which are hydrophilic and accessible, these parameters were used to predict the epitopes. The number of predicted helix (one) and sheet (five) regions in the Iranian isolate was equal to these numbers in subtypes A and F. Hubbard method recognized seven potential glycosylation sites on the Iranian isolate. In all other HIV-1 viruses, the number of putative glycosylation sites was less. In all subtypes, including the Iranian one, an epitope in the same region was predicted. In all analyzed sequences (excluding the Iranian one and subtypes D and H) a single long epitope was predicted in another region. In subtype H no epitope was predicted in that region. Similar to subtype D in the Iranian subtype B, two short epitopes were predicted in the same part. The computational analysis predicted similarities and dissimilarities between the locations of epitopes of the Iranian and other HIV-1 viruses. Although the primary structure of gp120 of the Iranian HIV-1 is highly related to subtype B, some differences were even predicted between the secondary and tertiary structure of the Iranian and consensus subtype B.

---

Flysch – Iranshahr – makran-Structure-Penci