Histological study of different layers of oocyte in stellate sturgeon (Acipenser stellatus)

The present study was conducted on a large number of oocytes collected from 36 female Acipenser stellatus brood fish caught from fishing grounds in the Guilan province and transferred to the Shahid Behesti Sturgeon Breeding Center during 1997-1998. Physiological assessments were carried out on the microscopic sections prepared from these oocytes. Under normal conditions, 9 distinguishable layers were observed in the sections prepared from A. stellatus oocytes that included the follicle, the outer most layer, followed by a jelly coat, an external zona radiata, internal zona radiata, fat layer, pigments, cytoplasm, nucleus and nucleoli. The presence of erythrocytes and micropyle canal in the oocytes indicate normal embryognesis among them

Comparative study of biochemical and hematological features in reared sturgeons

Suitable physiological condition in fishes for the selection of broodfishes can be achieved through hematological studies. The present study aimed to examin the hematological indices in Juvenile Sturgeons at different stages of growth. Total albumin content in blood serum, hemoglobin concentration, the erythrocyte and leukocyte count of 54 sturgeon specimens (Persian sturgeon Acipenser persicus and Great sturgeon Huso huso) were determined at the age of 1, 2 and 6 years reared fish. In the Persian sturgeon specimens studied, total albumin concentration increased from 26.1 to 52.5 gL-1, hemoglobin from 42.2 to 65.8 gL-1, erythrocyte count from 240 to 452.5 thousand cells/ μL-1, and leukocyte count from 17.4 to 46.7 thousand cells/ μL-1. The total leukocyte was composed of 73.2-82.7% lymphocytes, 12.3 to 20% neutrophils, 2.2 to 6.5% eosinophils and 0.2 to 2.5% monocytes with the increase of age. In the great sturgeon specimens studied, total albumin concentrations in blood increased from 20 to 42.4 g L-1, hemoglobin from 46.3 to 78.6 g L-1, and erythrocyte count from 495 to 735 thousand cells μL-1. The total leukocyte was composed of 54.5 to 67.5% lymphocytes, 6.1 to 26.9 % neutrophils, 6.6 to 13.25% eosinophils and 0.6 to 2.5% monocytes with the increase of age.This research revealed the evolutionary trends of hematological features in the natural growth and development of sturgeons in the South Caspian Sea, reared in artificial conditions and shows that with the increase in age, the hematological indices also increased

A tight lower bound instance for k-means++ in constant dimension

The k-means++ seeding algorithm is one of the most popular algorithms that is used for finding the initial $k$ centers when using the k-means heuristic. The algorithm is a simple sampling procedure and can be described as follows: Pick the first center randomly from the given points. For $i > 1$, pick a point to be the $i^{th}$ center with probability proportional to the square of the Euclidean distance of this point to the closest previously $(i-1)$ chosen centers. The k-means++ seeding algorithm is not only simple and fast but also gives an $O(\log{k})$ approximation in expectation as shown by Arthur and Vassilvitskii. There are datasets on which this seeding algorithm gives an approximation factor of $\Omega(\log{k})$ in expectation. However, it is not clear from these results if the algorithm achieves good approximation factor with reasonably high probability (say $1/poly(k)$). Brunsch and R\"{o}glin gave a dataset where the k-means++ seeding algorithm achieves an $O(\log{k})$ approximation ratio with probability that is exponentially small in $k$. However, this and all other known lower-bound examples are high dimensional. So, an open problem was to understand the behavior of the algorithm on low dimensional datasets. In this work, we give a simple two dimensional dataset on which the seeding algorithm achieves an $O(\log{k})$ approximation ratio with probability exponentially small in $k$. This solves open problems posed by Mahajan et al. and by Brunsch and R\"{o}glin.Comment: To appear in TAMC 2014. arXiv admin note: text overlap with arXiv:1306.420

Pyrrhotite Fe₁₋ₓS microcubes as a new anode material in potassium-ion batteries

Potassium-ion batteries are an emerging energy storage technology that could be a promising alternative to lithium-ion batteries due to the abundance and low cost of potassium. Research on potassium-ion batteries has received considerable attention in recent years. With the progress that has been made, it is important yet challenging to discover electrode materials for potassium-ion batteries. Here, we report pyrrhotite Fe1−xS microcubes as a new anode material for this exciting energy storage technology. The anode delivers a reversible capacity of 418 mAh g−1 with an initial coulombic efficiency of ~70% at 50 mA g−1 and a great rate capability of 123 mAh g−1 at 6 A g−1 as well as good cyclability. Our analysis shows the structural stability of the anode after cycling and reveals surface-dominated K storage at high rates. These merits contribute to the obtained electrochemical performance. Our work may lead to a new class of anode materials based on sulfide chemistry for potassium storage and shed light on the development of new electrochemically active materials for ion storage in a wider range of energy applications

Bidirectional PageRank Estimation: From Average-Case to Worst-Case

We present a new algorithm for estimating the Personalized PageRank (PPR) between a source and target node on undirected graphs, with sublinear running-time guarantees over the worst-case choice of source and target nodes. Our work builds on a recent line of work on bidirectional estimators for PPR, which obtained sublinear running-time guarantees but in an average-case sense, for a uniformly random choice of target node. Crucially, we show how the reversibility of random walks on undirected networks can be exploited to convert average-case to worst-case guarantees. While past bidirectional methods combine forward random walks with reverse local pushes, our algorithm combines forward local pushes with reverse random walks. We also discuss how to modify our methods to estimate random-walk probabilities for any length distribution, thereby obtaining fast algorithms for estimating general graph diffusions, including the heat kernel, on undirected networks.Comment: Workshop on Algorithms and Models for the Web-Graph (WAW) 201

Effects of dietary isoflavone-genistein on hematological and immunological parameters in pre-brood stock beluga, Huso huso

This study was carried out with the aim of detecting the dietary effects of isoflavone-genistein on hematological and immunological parameters in beluga, Huso huso in a 12-week feeding period. Five isonitrogenous (45% crude protein) and isoenergetic (19.5 MJ kg^-1) diets were formulated to contain four graded levels of isoflavone-genistein, namely 0, 0.2, 0.4, 0.8 and 1.6 g kg^-1 diet. Fish (initial average weight: 26.1 ± 1.8 kg) were stocked in ponds in groups of 3 and fed the experimental diets in triplicate. At the end of experiment, physiological indicators, including hematological and immunological parameters, such as red blood cell (RBC), white blood cell count (WBC), hematocrit (Ht), hemoglobin (Hb), lymphocyte, neutrophil, eosinophil, monocyte, haematological indices, lysozyme, total immunoglobulin (IgM) and complementary activities were determined. Results suggested that mean corpuscular hemoglobin concentration (MCHC) and values of neutrophil had significant differences between treatments. The activities of serum lysozyme, IgM, C3 and C4 were significantly influenced by the dietary genistein concentrations. Results indicated that genistein had significant effects on some hematological and immunological parameters in beluga

Growth performance, carcass composition, and immunophysiological indices in juvenile great sturgeon (Huso huso) fed on commercial prebiotic, Immunoster

Growth performance, carcass composition, and immunophysiological indices in juvenile great sturgeon (Huso huso) fed on commercial prebiotic Immunoster (IS) were investigated. After a four-week acclimatization period, 270 great sturgeon juveniles weighing 95.68 ± 10.05 g were randomly distributed into 9 fiberglass tanks in three replicates and kept at a density of 30 fish per tank for a period of 8 weeks at water temperature 20.55 ± 5.11ºC and dissolved oxygen 6.73 ± 0.35 mg L^-1. IS was added at two levels of 1% and 3% to the basal diet in place of cellulose. At the end of the trial, blood sampling and carcass analysis were conducted. Weight, length, body weight increase (BWI), specific growth rate (SGR), feed conversion ratio (FCR), protein efficiency ratio (PER) and condition factor (CF) were significantly affected by IS 3% compared with IS 1% and the control (P<0.05). There was significant difference (P<0.05) in crude protein of carcass between the experimental groups. Mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) showed significantly higher levels in experimental treatments compared with the control (P<0.05). Immunoglobulin M (IgM) level and lysozyme activity in IS 1% group were higher than the control group. It can be concluded that IS can enhance growth performance and improve some immunophysiological indices of great sturgeon

Blood serum osmotic and ionic regulation of wild adults and reared juvenile Persian sturgeon, Acipenser persicus

The osmoregulatory system was studied in wild adult and reared juvenile Persian sturgeon, Acipenser persicus. The mean osmolarity in blood serum of specimens from the Caspian Sea, estuary, the Kouraneski pools and the rearing tanks were 305.3±14.3, 308.7±25.8, 265.0±19.1 and 259.3±8.8 mosmol/L, respectively; the mean concentrations of Na+ were 151.2±6.3, 152.2±8.4, 142.5±5.9 and 131.4±4.1 meq/L whereas mean concentrations of K+ were 2.7±0.9, 3.6±0.9, 3.1±0.5 and 2.6±0.5meq/L, respectively. The concentrations for Mg++ ion in fish of the same four origins were 1.5±0.2; 1.5±0.3, 0.8±0.2 and 0.7±0.2 meq/L, and those of Ca++ were 2.31±0.51, 2.61±0.51, 1.85±0.58 and 1.46±0.43, respectively. The Pearson's correlation coefficient and regression equation indicated that Mg++(r =0.38) and Na+ (r=0.41) were effective ions for determination of blood serum osmotic pressure in A. persicus in brackish water and freshwater. This study also showed that blood serum osmotic pressure was independent of sex

Comparing sex hormones levels in Acipenser persicus at the onset of autumnal migration

Levels of two main steroid hormones in gonads, 17-B Stradiol (E2) and testosterone (T) were compared in males and females of Persian sturgeon at the start of autumnal migration to spawning rivers. Hormone levels were also studied for likely relationship with different stages of sexual maturity. The results showed that levels of T and E2 in females at the stage four of sexual maturity is significantly higher than the individuals with immature gonads (ovary in stages 2 and 3). We measured 11.81±2.86Omg/ml and 7±1.15mg/ml of T and E2 in mature females compared to 0.2±0.09mg/ml and 0.736±0.161mg/ml of T and E2 in immature females. Levels of the two hormones in males at different stages of sexual maturity showed that only testosterone was significantly different in mature and immature sturgeons (0.50±0.144 mg/ml and al 4.3 I 25±3.121mg/ml in mature and immature males, respectively) (P=0.04). In males and females with higher sexual maturity, differences between the two hormones were significant (T and E2 levels in females and males were 11.81±2.860mg/ml, 7±1.15mg/ml and 0.50±0.144mg/ml, 0.7023±0/212ng/ml, respectively). However, in immature fish of both sexes, only males showed significantly higher T levels (14.312513.121mg/ml in comparison with 0.2±0.09mg/ml). Disregarding the sexual maturity stages, we found significantly different levels of E2 in both sexes (4.779±1.827mg/ml in females and 0.709±0.121mg/ml in males) (P=0.00). Statistical analyses indicated no correlation between fish age and levels of steroid hormones of the fish (at 90% confidence level)