Dry and wet spells at Itabaina (NE Brazil)

Results of a study of dry and wet spells at Itabaina, a semi-arid station in northeast Brazil, are presented in this paper. Frequency distributions of dry spells of different durations at the station are compared with those derived from three statistical models. It is found that the Eggenberger-Polya and the geometric model provide better results than the logarithmic model. Frequency distribution of wet spells during the three rainiest months of the year shows that rainfall persistency reaches a maximum value on the fifth day of a rainy spell

A Review on Edge Detection Algorithms in Digital Image Processing Applications

Edge detection is one of the major step in Image segmentation, image enhancement, image detection and recognition applications. The main goal of edge detection is that to localize the variation in the intensity of an image to identify the phenomena of physical properties which produced by the capturing device. An edge might be characterized as a set of neighborhood pixels that forms a boundary between two different regions. Detecting the edges is an essential technique for segmenting the image in to various regions based on their discontinuity in the pixels. Edge detection has very important applications in image processing and computer vison. It is broadly used technique and quick feature extraction technique hence used in various feature extraction and feature detection techniques. There exists several methods in the literature for edge detection such as Canny, Prewitt, Sobel, Maar Hildrith, Robert etc. In this paper we have studied and compared Prewitt, Sobel, and Canny detection operators. Our experimental study shows that the canny operator is giving better results for different kinds of images and has numerous advantages than the other operators such as the nature of adaptive, works better for noisy images and providing the sharp edges with low probability of false detection edges

AZINE DYES AS SIMULTANEOUS KINETIC DETERMINATION OF AMINO ACID USING CHLORAMINE-B OXIDISING AGENT

Abstract Differential reaction rate methods are an area of recent exploitation in chemical analysis for the resolution of mixtures of closely related species

A Novel Multi-Band Patch Antenna on Metamaterial Substrate for Ku band applications

In this paper, a metamaterial based compact multiband microstrip antenna is proposed which can give high gain and directivity. Metamaterial are periodic structures and have been intensively investigated due to the particular features such as ultra-refraction phenomenon and negative permittivity and/or permeability. A metamaterial based microstrip patch antenna with enhanced characteristics and multi band operation will be investigated in this work. The multiple frequency operation will be achieved by varying the capacitance of the metamaterial structure with the help of metallic loadings placed in each metamaterial unit cells. The potential impacts will be miniaturization, reduced cost and reduced power consumption since multiple antennas operating at different frequencies are replaced by a single antenna which can operate at multiple frequencies. The proposed microstrip patch antenna will have its frequencies of operation in the Ku band. The proposed structure is simulated using HFSS

आँध्रप्रदेश के समुद्री मात्स्यिकी स्रोत - एक पर्यावलोकन

आँध्रप्रदेश के समुद्री मात्स्यिकी स्रोत - एक पर्यावलोक

Rhodobium gokarnense sp. nov., a novel phototrophic alphaproteobacterium from a saltern

A pink-pigmented, phototrophic, purple nonsulfur bacterium, strain JA173T, was isolated in pure culture from a saltern in Gokarna, India, in a medium containing 2 % (w/v) NaCl. Strain JA173T was a non-motile Gram-negative rod that multiplied by budding. Phylogenetic analysis based on 16S rRNA gene sequences showed that strain JA173T clusters with the class Alphaproteobacteria; highest sequence similarity (98 %) was to the type strain of Rhodobium orientis and 94 % similarity was observed to the 16S rRNA gene sequence of the type strain of Rhodobium marinum. However, DNA–DNA hybridization with R. orientis DSM 11290T revealed a relatedness value of only 35.1 % with strain JA173T. Strain JA173T contained lamellar internal membranes, bacteriochlorophyll a and carotenoids of the spirilloxanthin series. Strain JA173T had an obligate requirement for NaCl (optimum growth at 2–6 %, w/v) and grew photoheterotrophically with a number of organic compounds as carbon source or electron donor. Photoautotrophic, chemoautotrophic and fermentative growth could not be demonstrated. Yeast extract was required for growth. Based on 16S rRNA gene sequence analysis, DNA–DNA hybridization data and morphological and physiological characteristics, strain JA173T is sufficiently different from other species of the genus Rhodobium to be recognized as a representative of a novel species, Rhodobium gokarnense sp. nov. The type strain is JA173T (=ATCC BAA-1215T=DSM 17935T=JCM 13532T)

Estimation of incoming global solar radiation and its diffuse component at the surface in Paraiba state (NE Brazil)

Results of a study on the estimation of mean monthly values of incoming global solar radiation and its diffuse component at some stations in Paraiba state (NE Brazil) are presented in this paper. Radiation data at four stations is used. ˚Angstr¨om-type equations are derived for the estimation of global radiation and the diffuse fraction of global radiation is expressed in terms of the clearness index and the sunshine ratio. The applicability of previously reported equations for stations in this region is investigated

Two novel species of marine phototrophic Gammaproteobacteria: Thiorhodococcus bheemlicus sp. nov. and Thiorhodococcus kakinadensis sp. nov.

Two coccoid phototrophic purple sulfur bacteria were isolated from marine habitats (marine aquaculture pond near Bheemli, Visakhapatnam and marine tidal waters from a fishing harbour, Kakinada) in a medium that contained 3 % NaCl (w/v). Strains JA132T and JA130T are Gram-negative, motile cocci with a single flagellum. Both have an obligate requirement for NaCl. Intracellular photosynthetic membranes are of the vesicular type. Bacteriochlorophyll a and most probably carotenoids of the spirilloxanthin series were present as photosynthetic pigments. Both strains were able to grow photolithoautotrophically and photolithoheterotrophically. Chemotrophic and fermentative growth could not be demonstrated. There is no vitamin requirement for strain JA132T, while strain JA130T requires niacin, biotin and pantothenate as growth factors. Phylogenetic analysis on the basis of 16S rRNA gene sequences showed that both strains cluster with species of the genus Thiorhodococcus belonging to the Gammaproteobacteria. The DNA G+C contents of strains JA132T and JA130T were 65.5 and 57.5 mol%, respectively. Based on the 16S rRNA gene sequence analysis, morphological and physiological characteristics, strains JA132T and JA130T are significantly different from each other and from other species of the genus Thiorhodococcus and are recognized as two novel species, for which the names Thiorhodococcus bheemlicus sp. nov. and Thiorhodococcus kakinadensis sp. nov. are proposed. The type strains of T. bheemlicus sp. nov. and T. kakinadensis sp. nov. are JA132T (=MTCC 8120T=ATCC BAA-1362T=JCM 14149T=DSM 18805T) and JA130T (=ATCC BAA-1353T=DSM 18858T=JCM 14150T), respectivel

Characteristics of VHF radiowave scintillations over a solar cycle (1983?1993) at a low-latitude station: Waltair (17.7°N, 83.3°E)

International audienceThe characteristics of VHF radiowave scintillations at 244 MHz (FLEETSAT) during a complete solar cycle (1983?93) at a low-latitude station, Waltair (17.7°N, 83.3°E), are presented. The occurrence of night-time scintillations shows equinoctial maxima and summer minima in all the epochs of solar activity, and follows the solar activity. The daytime scintillation occurrence is negatively correlated with the solar activity and shows maximum occurrence during the summer months in a period of low solar activity. The occurrence of night-time scintillations is inhibited during disturbed days of high solar activity and enhanced during low solar activity