Heavy metals (Ni, Cd, Pb, Cu) concentrations in seaweed and sediments along the coastal areas of Hormuzgan province (Bandar Abbas and Bandar Lengeh)

Metals concentrations were studied in dominant seaweeds and their adjacent sediments in Bandar Abbas and Bandar Lengeh tidal areas. The status of selected heavy metals (Ni, Cd, Pb, Cu) was determined in sediments and 15 dominant seaweed species including 4 species of Chlorophyta, 4 species of Phaeophyta and 7 species of Rhodophyta. Samples of seaweed and sediment were collected seasonally during November 2007 to August 2008 from intertidal regions of nine sites along the Bandar Abbas and Bandar Lengeh coasts. Powdered samples of sediments and seaweed were digested and analyzed using Atomic Absorption Spectrophotometer (A.A.S). Concentrations of Cu, Pb, Cd, and Ni were 5.24, 20.44, 5.40 and 33.83µg/g -1 dry wt. in sediments. Concentration of these metals in µg/g -1 dry weight in Chlorophyta were 11.11, 25.79, 4.76 and 46.57, in Phaeophyta were 9.18, 17.68, 4.82 and 36.65, and in Rhadophyta were 9.80, 21.03, 4.96 and 50.43, respectively. The marine seaweed species collected during all seasons and sites in Bandar Abbas and Bandar Lengeh were identified as Entromorpha compressa and Padina pavonica, respectively

Population genetic study on two commercial shrimp species and determining of DNA-Barcoding of 6 – 8 species by partial sequencing of mtDNA using molecular method (PCR-Sequencing)

Barcodes are short segments of DNA that can be used to uniquely identify an unknown specimen to species, particularly when diagnostic morphological features are absent. These sequences could offer a new forensic tool in plant and animal conservation especially for endangered species. Ideally, barcodes could be used to positively identify illegally obtained material even in cases where diagnostic features have been purposefully removed or to release confiscated organisms into the proper breeding population. In the present study molecular data were used besides the morphological ones to introduce a specific barcode for six selected species of Shrimp. Based on the previous phylogenetics study, it has been proved that the mitochondrial COI gene in crustacean is a good discriminative marker at both inter- and intra-specific levels. In this regard, six species of shrimp (Fenoro penaeus indicus, Fenoro penaeus merguensis, penaeus semisulcatus, Metapenaeus affinis, Marsupenaeus japonicas, Fenoro penaeus penicillatus were collected from the Persian Gulf and Oman sea. After identification, the total DNA was extracted; COI gene was first amplified and then sequenced for each species. Finally the collected data were analyzed with the specific phylogenetic software. Molecular analysis revealed some degree of interpopulation differences but six good species were recognizable based on COI sequences. Also for population study molecular data of two species Penaeus semisulcatus and Metapenaeus affinis were analysed base on COI RFLP and 16SrRNA sequences respectively. The results would be helpful to protect shrimp species

The importance of anisotropic Coulomb interaction in LaMnO3

In low-temperature anti-ferromagnetic LaMnO3, strong and localized electronic interactions among Mn 3d electrons prevent a satisfactory description from standard local density and generalized gradient approximations in density functional theory calculations. Here we show that the strong on-site electronic interactions are described well only by using direct and exchange corrections to the intra-orbital Coulomb potential. Only DFT+U calculations with explicit exchange corrections produce a balanced picture of electronic, magnetic and structural observables in agreement with experiment. To understand the reason, a rewriting of the functional form of the +U corrections is presented that leads to a more physical and transparent understanding of the effect of these correction terms. The approach highlights the importance of Hund’s coupling (intra-orbital exchange) in providing anisotropy across the occupation and energy eigenvalues of the Mn d states. This intra-orbital exchange is the key to fully activating the Jahn-Teller distortion, reproducing the experimental band gap and stabilizing the correct magnetic ground state in LaMnO3. The best parameter values for LaMnO3 within the DFT(PBEsol)+U framework are determined to be U = 8 eV and J = 1.9 eV

Texture Coding in the Rat Whisker System: Slip-Stick Versus Differential Resonance

Rats discriminate surface textures using their whiskers (vibrissae), but how whiskers extract texture information, and how this information is encoded by the brain, are not known. In the resonance model, whisker motion across different textures excites mechanical resonance in distinct subsets of whiskers, due to variation across whiskers in resonance frequency, which varies with whisker length. Texture information is therefore encoded by the spatial pattern of activated whiskers. In the competing kinetic signature model, different textures excite resonance equally across whiskers, and instead, texture is encoded by characteristic, nonuniform temporal patterns of whisker motion. We tested these models by measuring whisker motion in awake, behaving rats whisking in air and onto sandpaper surfaces. Resonant motion was prominent during whisking in air, with fundamental frequencies ranging from approximately 35 Hz for the long Delta whisker to approximately 110 Hz for the shorter D3 whisker. Resonant vibrations also occurred while whisking against textures, but the amplitude of resonance within single whiskers was independent of texture, contradicting the resonance model. Rather, whiskers resonated transiently during discrete, high-velocity, and high-acceleration slip-stick events, which occurred prominently during whisking on surfaces. The rate and magnitude of slip-stick events varied systematically with texture. These results suggest that texture is encoded not by differential resonant motion across whiskers, but by the magnitude and temporal pattern of slip-stick motion. These findings predict a temporal code for texture in neural spike trains

Population genetic structure of silver pomfret, Pampus argenteus, in Persian Gulf and Oman Sea in Iran and Kuwait waters by using10 Microsatellite Markers

The silver pomfret, Pampus argenteus, is distributed in Indo-western pacific ocean, especially in Persian Gulf and Oman sea, and although is widely commercially exploited, the genetics structure of this species is not clear completely. In the present study, the genetic diversity and population structure of Pampus argentus in the Persian Gulf and Oman Sea were investigated using microsatellite DNA markers. Genomic DNA from 125 specimens was extracted and PCR amplification performed. Seven loci with reasonable polymorphism were amplified. The results showed that average of observed heterozygosity was ranged from 0.54 while expected heterozygosity was 0.67. After applying the Hardy-Weinberg Equilibrium (HWE) test, some loci were found to be significantly deviated from HWE in some populations in which deficiency of heterozygotes was apparent. Population differentiation observed among all populations (P<0.01). The population differentiation (Fst) value between Kuwait and bushehr was the highest and significant (0.087) and between Chabahar and Bushehr (0.021) was the lowest and significant. Genetic distance analysis showed that the largest distance (0.269) was between Khuzestan and Chabahar and the smallest distance (0.075) was between Bushehr and Chabahar. The reported results could be of interest for management and conservation programmes of this species in the Persian Gulf and Oman Sea

Comparing modeling of pollution in Arvand River in the dry and wet seasons

Water resources under threat of pollution such as industrial waste, fertilizers, pesticides and urban sewage that negative effects on the environment and ecosystems. Arvand River is one of the most important navigable rivers in Iran، and it’s the most traffic place for floating which don’t have any system for delivery waste materials and discharging these waste materials in water making oil pollution. In this research, modeling pollution in the Arvand River using three-dimensional and hydrodynamic model to simulate how the pollution is studied, the Navier-Stokes equations in three dimensions and equations are solved transfer salinity and water temperature separation method. Boundary conditions applied، including changes in temperature، salinity and flow rate، temperature and salinity changes and apply for open border river and tidal components O1، S2، M2 and K1 open sea in the model used for the border. In this research, modeling pollution in the Arvand River using coherence and hydrodynamic modeling to simulate how the pollution is studied. The results of modeling pollution in Arvand After running the model revealed that the pollution is pollution in the Arvand River according to location and time of release، in other words، in the Arvand River pollution from one point to another and from season to season is different، in fact، pollution is reciprocating mode. Diffusion of oil pollution in Arvand rood is depending to current. In low tide because of same side of river current is more. And in low tide because of same side of river current with low tide pollution reached to the Persian Gulf with high speed. The results shows, represent the effect of tie on diffusion pollution

Effect of Semicore Orbitals on the Electronic Band Gaps of Si, Ge, and GaAs within the GW Approximation

We study the effect of semicore states on the self-energy corrections and electronic energy gaps of silicon, germanium and GaAs. Self-energy effects are computed within the GW approach, and electronic states are expanded in a plane-wave basis. For these materials, we generate {\it ab initio} pseudopotentials treating as valence states the outermost two shells of atomic orbitals, rather than only the outermost valence shell as in traditional pseudopotential calculations. The resulting direct and indirect energy gaps are compared with experimental measurements and with previous calculations based on pseudopotential and ``all-electron'' approaches. Our results show that, contrary to recent claims, self-energy effects due to semicore states on the band gaps can be well accounted for in the standard valence-only pseudopotential formalism.Comment: 6 pages, 3 figures, submitted to Phys. Rev.

An In Vitro Pipeline for Screening and Selection of Citrus-Associated Microbiota with Potential Anti-"Candidatus Liberibacter asiaticus" Properties.

Huanglongbing (HLB) is a destructive citrus disease that is lethal to all commercial citrus plants, making it the most serious citrus disease and one of the most serious plant diseases. Because of the severity of HLB and the paucity of effective control measures, we structured this study to encompass the entirety of the citrus microbiome and the chemistries associated with that microbial community. We describe the spatial niche diversity of bacteria and fungi associated with citrus roots, stems, and leaves using traditional microbial culturing integrated with culture-independent methods. Using the culturable sector of the citrus microbiome, we created a microbial repository using a high-throughput bulk culturing and microbial identification pipeline. We integrated an in vitro agar diffusion inhibition bioassay into our culturing pipeline that queried the repository for antimicrobial activity against Liberibacter crescens, a culturable surrogate for the nonculturable "Candidatus Liberibacter asiaticus" bacterium associated with HLB. We identified microbes with robust inhibitory activity against L. crescens that include the fungi Cladosporium cladosporioides and Epicoccum nigrum and bacterial species of Pantoea, Bacillus, and Curtobacterium Purified bioactive natural products with anti-"Ca. Liberibacter asiaticus" activity were identified from the fungus C. cladosporioides Bioassay-guided fractionation of an organic extract of C. cladosporioides yielded the natural products cladosporols A, C, and D as the active agents against L. crescens This work serves as a foundation for unraveling the complex chemistries associated with the citrus microbiome to begin to understand the functional roles of members of the microbiome, with the long-term goal of developing anti-"Ca Liberibacter asiaticus" bioinoculants that thrive in the citrus holosystem.IMPORTANCE Globally, citrus is threatened by huanglongbing (HLB), and the lack of effective control measures is a major concern of farmers, markets, and consumers. There is compelling evidence that plant health is a function of the activities of the plant's associated microbiome. Using Liberibacter crescens, a culturable surrogate for the unculturable HLB-associated bacterium "Candidatus Liberibacter asiaticus," we tested the hypothesis that members of the citrus microbiome produce potential anti-"Ca Liberibacter asiaticus" natural products with potential anti-"Ca Liberibacter asiaticus" activity. A subset of isolates obtained from the microbiome inhibited L. crescens growth in an agar diffusion inhibition assay. Further fractionation experiments linked the inhibitory activity of the fungus Cladosporium cladosporioides to the fungus-produced natural products cladosporols A, C, and D, demonstrating dose-dependent antagonism to L. crescens

Ab initio and finite-temperature molecular dynamics studies of lattice resistance in tantalum

This manuscript explores the apparent discrepancy between experimental data and theoretical calculations of the lattice resistance of bcc tantalum. We present the first results for the temperature dependence of the Peierls stress in this system and the first ab initio calculation of the zero-temperature Peierls stress to employ periodic boundary conditions, which are those best suited to the study of metallic systems at the electron-structure level. Our ab initio value for the Peierls stress is over five times larger than current extrapolations of experimental lattice resistance to zero-temperature. Although we do find that the common techniques for such extrapolation indeed tend to underestimate the zero-temperature limit, the amount of the underestimation which we observe is only 10-20%, leaving open the possibility that mechanisms other than the simple Peierls stress are important in controlling the process of low temperature slip.Comment: 12 pages and 9 figure