Informed Proposal Monte Carlo

Any search or sampling algorithm for solution of inverse problems needs guidance to be efficient. Many algorithms collect and apply information about the problem on the fly, and much improvement has been made in this way. However, as a consequence of the the No-Free-Lunch Theorem, the only way we can ensure a significantly better performance of search and sampling algorithms is to build in as much information about the problem as possible. In the special case of Markov Chain Monte Carlo sampling (MCMC) we review how this is done through the choice of proposal distribution, and we show how this way of adding more information about the problem can be made particularly efficient when based on an approximate physics model of the problem. A highly nonlinear inverse scattering problem with a high-dimensional model space serves as an illustration of the gain of efficiency through this approach

Population genetic structure analysis of the freshwater crayfish (Astacus leptodactylus) in different region inferred from mtDNA control region sequencing

In this study population genetic structure of freshwater crayfish (Astacus leptodactylus) in Iran was investigated using direct sequencing of mtDNA control region. A total of 132 samples were collected from the different locations. The quality and quantity of total DNA were determined by agarose gel electrophoresis ethidium bromide staining and spectrophotometery, respectively. The results showed that 38 haplotypes were observed between samples in sequencing analyses. The haplotype diversity (h) and nucleotide diversity (π) were 0.811±0.049 and 0.0127±0.0038 sequencing techniques, respectively. Tajima’s D and chi-square (χ 2) values were 3.120 and 78.25, respectively. The significant positive D value for the samples might suggest balancing selection. Significantly negative Fu's Fs values and significantly positive Harpending test values were taken as evidence of a population expansion.The results of FST ,Exact test and analysis of molecular variance (AMOVA) demonstrated that samples between Siahdarvishan River , Jafrood River and Astara region in the southwest Caspian sea statistically are significant in sequencing techniques (P< 0.0001). These results suggests that the unique genetic structure of Siahdarvishan River, Jafrood River and Astara region represent a highly valuable genetic resource and provide useful information for identifying populations and genetic improvemnet

Performance evaluation of MISO-SDMA in heterogenous networks with practical cell association

In this paper adopting stochastic geometry we investigate the system performance in heterogenous networks including multiple tiers of BSs with multiple-input single output spatial division multiple access (MISO-SDMA) technique. In the related literature on heterogenous systems, ideal cell association (CA) rules are often considered for simplicity, where each user equipment (UE) examines a very large number of pilots across the tiers before choosing its associated base station (BS). Here we consider practical cases where UEs are restricted to examine KH≥1 pilots across all tiers before choosing their associated BS. We then obtain closed-form expressions for the system performance measured by the coverage probability and UE's data rate. Our analytical results provide quantitative insights on the impact of different factors on the system performance including the BS's spatial density, their transmission powers, number of transmit antennas, SIR thresholds, number of UEs served by each BS, and KH. Interestingly, we observe that increasing KH always improves the coverage probability however, it only improves data rate up to a certain point. The data rate is then reduced by further increasing of KH. Given KH pilots in practical cases, the issue is how to allocate the pilots among different tiers. We address this issue by developing an algorithm and show that by careful allocation of available pilots, the network performance is significantly improved even in cases with small KH. Our results also indicate a fundamental tradeoff, as sharing strategies providing the best coverage performance yield very poor capacity and vice versa. Such trade-off provides a new degree of freedom in heterogeneous networks design

Genetic relationships among collections of the Persian sturgeon, Acipenser persicus, in the south Caspian Sea detected by mitochondrial DNA–Restriction fragment length polymorphisms

In the present study, mitochondrial DNA polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) assay was used to assess the population structure and genetic relationships among six Persian sturgeon, Acipenser persicus populations from the south Caspian Sea along the Iranian coast. The complete nucleotide dehydrogenase subunit 5 (NADH 5) region of mtDNA amplified by PCR was digested with five restriction enzymes. In total, 154 individuals from six populations including: Guilan (Zone1-2), Mazandaran (Zone 3 and 5), Golestan (Zone 4) and Sefidroud River, from the south Caspian Sea along the Iranian coast were analyzed using five restriction endonucleases (Rsa І, Hinf І, HaeIII, Mbo І and Cfr13І), yielding 17 haplotypes. Samples from Sefidroud River were clearly identified by cluster and molecular variance model (AMOVA) analyses. This collection showed dominant haplotypes that were little in populations from the other geographic areas. The mean haplotype diversity (h) and nucleotide diversity (π) were 0.739±0.038 and 0.0105±0.0043, respectively. Based on heterogeneity test haplotype frequencies of Persian sturgeon populations and Monte-Carlo with 1000 replicates in PCR-RFLP method significant differences were seen (χ2 =37.12, P< 0.0001) and these results showed that haplotype distribution in different location were significant and populations of Sefidroud River were statistically significant (P< 0.0001). This result suggests that the unique genetic structure of Sefidroud River represents a highly valuable genetic resource and should now be treated as demographically independent and managed separately

Effect of dietary digestible energy level on growth indices of kutum (Rutilus frisii kutum Kamenskii, 1901)

A 60-days feeding trial was conducted to evaluate the effects of dietary digestible energy levels (DE) on kutum, Rutilus frisii kutum. Four isonitrogenous (35% protein) diets with digestible energy levels of 2500, 2600, 2700 and 2800kcal kg-1 were tested. Two hundred and forty advanced fry (2±0.4g) were randomly distributed in 12 fiberglass tanks of 400L capacity. Nutritional responses in terms of WG, FCR and PER as well as survival rate (SR) significantly improved (P<0.05) with increase in DE level from 2500 to 2800 kcal kg-1 diet, but no difference between 2600 and 2700kcal kg-1 diet was found. Body crude protein and fat significant were increased (p<0.05) when the dietary energy was raised up from 2500 to 2600kcal DE kg-1 diet, but a further increase on energy did not improve the fish crude protein and fat content