The Mystery of the Asymptotic Quasinormal Modes of Gauss-Bonnet Black Holes

We analyze the quasinormal modes of $D$-dimensional Schwarzschild black holes with the Gauss-Bonnet correction in the large damping limit and show that standard analytic techniques cannot be applied in a straightforward manner to the case of infinite damping. However, by using a combination of analytic and numeric techniques we are able to calculate the quasinormal mode frequencies in a range where the damping is large but finite. We show that for this damping region the famous $\ln(3)$ appears in the real part of the quasinormal mode frequency. In our calculations, the Gauss-Bonnet coupling, $\alpha$, is taken to be much smaller than the parameter $\mu$, which is related to the black hole mass.Comment: 12 pages and 5 figure

The first record of Philometra rischta (Nematoda: Philometridae) in Blicca bjoerkna of Anzali wetland, Iran

The aim of the present study was to report Philometra rischta from Blicca bjoerkna from the Caspian Sea. During this study, from August (2008) to April (2009), 78 fish specimens were collected and transferred to the aquatic research laboratory of Shahid Beheshti University and were examined for parasitic infection. Parasites were fixed in formalin (10%). The parasites were indentified according to standard keys (Moravec, 1994, 1998). Prevalence (total of infected fish per total of fish) and mean intensity (number of parasite per total of infected of fish) were calculated for this parasite

Quasinormal modes for the charged Vaidya metric

The scalar wave equation is considered in the background of a charged Vaidya metric in double null coordinates $(u,v)$ describing a non-stationary charged black hole with varying mass $m(v)$ and charge $q(v)$. The resulting time-dependent quasinormal modes are presented and analyzed. We show, in particular, that it is possible to identify some signatures in the quasinormal frequencies from the creation of a naked singularity.Comment: 4 pages. Prepared for the proceedings of the Spanish Relativity meeting (ERE2010), Granada, Spain, September 6-10, 201

No-go theorem for false vacuum black holes

We study the possibility of non-singular black hole solutions in the theory of general relativity coupled to a non-linear scalar field with a positive potential possessing two minima: a `false vacuum' with positive energy and a `true vacuum' with zero energy. Assuming that the scalar field starts at the false vacuum at the origin and comes to the true vacuum at spatial infinity, we prove a no-go theorem by extending a no-hair theorem to the black hole interior: no smooth solutions exist which interpolate between the local de Sitter solution near the origin and the asymptotic Schwarzschild solution through a regular event horizon or several horizons.Comment: 16 pages, 1 figure, Latex, some references added, to appear in Classical and Quantum Gravit

Generic master equations for quasi-normal frequencies

Generic master equations governing the highly-damped quasi-normal frequencies [QNFs] of one-horizon, two-horizon, and even three-horizon spacetimes can be obtained through either semi-analytic or monodromy techniques. While many technical details differ, both between the semi-analytic and monodromy approaches, and quite often among various authors seeking to apply the monodromy technique, there is nevertheless widespread agreement regarding the the general form of the QNF master equations. Within this class of generic master equations we can establish some rather general results, relating the existence of "families" of QNFs of the form omega_{a,n} = (offset)_a + i n (gap) to the question of whether or not certain ratios of parameters are rational or irrational.Comment: 23 pages; V2: Minor additions, typos fixed. Matches published versio

Survey of preservatives on shelf life of silver carp burger

In this research in order to assess the possibility of antioxidant effects in quality protection and increase the shelf alife of fish burgers, ascorbic acid as a antioxidant by natural source used in raw uncoated fish burgers and in order to comparison by vacuum packaging, 3 treatments of uncoated fish burgers produced from cultivated silver carp: 1- burgers by common packaging (control) 2- burgers by vacunm packaging 3- burgers by 500ppm Ascorbic acid. Also in order to comparison BHA+BHT antioxidants (that have synergistic effects to each other) effect by vacuum packaging to prevention of lipid oxidation in semi-fried fish burgers 3 other treatments produced too: 1- burgers by common packaging (control) 2- burgers by vacunm packaging 3-burgers by 200 ppm BHA+BHT antioxidants comparatively to fats of product. All of the burgers after production and freezing conserved in -18°c for 6 months (Raw uncoated burgers) and one year (Semi-fried coated burgers). During the storage period chemical, microbiological, and organoleptic tests were down by three repetition monthly. Although peroxide value in raw uncoated fish burgers were higher than standard range even from first month but it seems this factor is not suitable for quality evaluation of uncoated raw fish burgers. Evaluation of TBA index in raw uncoated fish burgers during storage time showed at the end of storage period TBA index for control, vacuum and ascorbic acid treatments were 6.31, 4.76 and 1.29 mg malonaldehyde/kg respectively and taste scores were 5.11, 5.42 and 6.16 respectively. Results indicate the positive effects of ascorbic acid to prevention of lipid oxidation. By attention to TVN, TBA and organoleptic tests 4 mounths for treatments without ascorbic acid by vacuum packaging preference and 6 months shelf life for ascorbic acid treatment have suggested in -18°c temperature. For semi fried fish burger 28 prevention effect for lipid oxidation but vacuum packaging had 32 (without significantly difference,P>0.05). so we can for %BHA+BHT treatment this property was recommend the use of vacuum packaging instead of antioxidant treatment. By attention to TVN, pH, PV, TBA and microbiological and organoleptic tests we can suggest the 8 months for shelf life time of semi fried fish burgers. In this product TVN was the only limitation factor and exeeded from standard range at 9th month of maintenance

Development of technology to extract beta-carotene natural colors from Azolla (Azolla filiculoides)

The present project was aimed at determining the content, quality, and purity of β-carotene extracted from Azolla filiculoides in the Anzali Wetland, comparing it with synthetic β-carotene, and measuring its economic value. One treatment had β-carotene derived from Azolla filiculoides in the Anzali Wetland through the alkaline hydrolysis method in the summer of 2014. Treatments were kept at 4°C for one year. Synthetic β-carotene was used as the control. The quality of the treatments was assessed by applying some chemical tests, including the measurement of the content and quality of β-carotene, colorimetry using the Hunter-LAB method, determination of the purity and vitamin A employing high-performance liquid chromatography (HPLC), estimation of the dwell-time duration at 5°C, and measurement of the solubility of β-carotene in water. Beta carotene of Azolla in the spring extracted to alkaline hydrolysis was11853 mg/kg, in summer was 9935mg/kg, in autumn was 11256 mg/kg and in winter was 11245 mg /kg. Beta carotene of Azolla in the spring extracted to organic solvent was 8347 mg/kg, in summer was 6648 mg/kg, in autumn was 7543 mg/kg and in winter was 7539 mg/kg. The amount of beta-carotene is extracted using organic solvents and alkaline hydrolysis in the summer compared to other seasons showed a significant reduction (P0.05). The extracted amounts of beta-carotene in organic solvents compared to alkaline hydrolysis method in seasons spring, summer, autumn and winter was difference significant (P0.05). According to the harvesting Azolla of wetland is not requires special equipment and in terms of time a lot of Azolla can be harvested in a short time and also for the extraction of beta-carotene from Azolla Anzali Lagoon is not requires special equipment, too, have no economic value of raw material, does not require special conditions for growing, doubling in three days, Azolla is rich in beta-carotene, beta-carotene extraction of large quantities of small amounts of starting material, the cost of chemical materials, labor, fuel, Laboratory equipment required and the cost of importing small packages beta-carotene, beta-carotene into the country in terms of economic cost compared to the cost of imported Sigma beta carotene is economical. As shown in Table 5 in the samples prepared by alkaline hydrolysis in comparison with synthetic chemical manufactured by Sigma in terms of colorimetric tests, purity, composition and solubility of vitamins significant difference was not observed (P>0.05). But, in samples prepared by organic solvents in comparison with synthetic chemical manufactured by Sigma in terms of colorimetric tests, purity, composition and solubility of vitamins significant difference was observed (P<0.05). According to significant differences between the amount of betacarotene extracted from Azoula wetland compared to other seasons in spring and autumn and winter plant growth in spring Azoula alkaline hydrolysis method for the extraction of beta-carotene wetland and wetland Azolla is recommended

Investigation and identification of helminth parasites in five fish species of Anzali Wetland

This study aimed to identify of helminth parasites in some native and economic fish of Anzali wetland was performed. 314 fish specimens, including: Alburnus hohenackeri (60 Specimen), Blicca bjoerkna (75 Specimen), Hemiculter leucisculus (75 Specimen), Pseudorasbora parva (52 pcs) Rhodeus amarus (52 Specimen), from Cyprinidae (Cyprinidae), during 1 year (2012-2013) and seasonally, from three different stations (Shijan, Pirbazar and Pasikhan) via gill net (50-70 mm) and fyke net were sampled. Samples were transported to the Inlandwater Aquaculture Institute in Bandar Anzali. In the laboratory, After biometry and determine the age and sex of fish, different body parts for searching of parasites were checked and parasites by using identification keys were identified. As a result of this study, 9 species of helminth parasites of fishes were identified include: Gyrodactylus sp., Dactylogyrus sphyrna , Dactylogyrus sp., Ligula intestinalis, Diplostomum paraspathaceum, Diplostomum spathaceum, Diplostomum sp., Posthodiplostomum cuticola and Rhabdochona denudate. The highest frequency of parasites in trematodes (in 5 fish species studied) and the minimum frequency in cestodes (each at 1 fish species studied) were seen. According to statistical analysis using Chi-Square test and KruskalWallis, the pollution of the sex, weight, length and sampling stations, there is no statistically significant difference (P> 0.05)

Study of parasites occurrence and intensity in fishes of Anzali Lagoon

Tish survey prolonged from summer 2011 trough summer 2012. During this period 574 samples of different fish species were investigated for their parasites. Totally 30 species of parasites isolated of the fishes. Some of the isolated parasites are recorded for the first time in Iran. Rafidascaris acus Orientocreadium siluri, Silurotaenia siluri, Acanthocephalus lucii , Argulus foliaceus has recorded for the first time from European catfish, Silurus glanis, and Dactylogyrus inexpectatus has recorded for the first time from Gibel Carp, Carassius auratus gibelio, in Anzali wetland. Statistical comparison of parasites infections and intensity between the different area of Anzali wetland were done. Infection of Pike, Esox lucius, to Diplostomum spathaceum, Raphidascaris acus and Monogenean in western parts of wetland were significantly different from the Eastern and Central areas (p<0.05). So based on the data have concluded the eastern and central regions of the wetland are more polluted than the western part. Comparing the results of the present study with before ones showed that the composition of parasite species has been changed over time, while the prevalence, intensity and abundance of parasites have been increased. It may be due to changing environmental conditions such as increasing discharge of effluent, eutrophication of the wetland. This results accents to necessity of reconstruction of Anzali wetland with preference of eastern and central regions

Determination of suitable size of Rutilus frisii kutum for releasing by evaluation of osmotic regulation ability

The study was done in Nutrition and Live Food Station was located in Bandar Anzali Ghaziyan. Juveniles weighted average 0.5, 1, 2.5, 5, 10, 15 and 20 g were randomly selected in three water conditions with a salinity of 11 ppt (Caspian sea water), water 7 ppt and freshwater (with three replicates per group) were included. At intervals of 0, 3, 6, 12, 24, 72, 168, 240 hours, blood samples were heparinized capillary tubes by caudal juveniles and ion concentrations Mg, Ca,Cl using the spectrophotometer and sodium and potassium ions with Flaym photometry (flame photometric), the osmotic pressure of blood plasma by osmometer and cortisol levels were measured by RIA method. To study the microstructure of gill and kidney tissue for each treatment , tissue samples by classical histological methods and stained with hematoxylin - eosin slides were prepared. The frequency and location of the enzyme Na^+, K^+ - ATPase and chloride cells with immunohistochemical localization was performed. Studies micrometric gill chloride cells and renal glomerular networks by software Image tool (version 2.0) was performed. Measurement of enzyme Na^+, K^+-ATPase, by Zaugg (1982) method was conducted. Data analyzed by one-way ANOVA (Oneway ANOVA) with Tukey's test was performed. Overall, the results of measuring ions and osmotic pressure on the tenth day of treatment, the osmotic potential juveniles 2.5, 5, 10, 20 gr in Caspian sea water and all groups except the 0.5 in water of 7 ppt confirmed. But in case of unfavorable conditions for the release in estuaries river and river, fish with weight 1 to 3 release directly to beach (where the salinity is 7 grams per liter) and fishes with weight from 10 to 20 gr to sea. Although suitable river conditions necessary condition for release of juveniles in riverine areas to adaptation juveniles occur gradually