Back-action ground state cooling of a micromechanical membrane via intensity-dependent interaction

We propose a theoretical scheme to show the possibility of achieving the quantum ground state cooling of a vibrating micromechanical membrane inside a high finesse optical cavity by back-action cooling approach. The scheme is based on an intensity-dependent coupling of the membrane to the intracavity radiation pressure field. We find the exact expression for the position and momentum variances of the membrane by solving the linearized quantum Langevin equations in the steady-state, conditioned by the Routh-Hurwitz criterion. We show that by varying the Lamb-Dicke parameter and the membrane's reflectivity one can effectively control the mean number of excitations of vibration of the membrane and also cool down the system to micro-Kelvin temperatures

Steady-state entanglement and normal-mode splitting in an atom-assisted optomechanical system with intensity-dependent coupling

In this paper, we study theoretically the bipartite and tripartite continuous variable entanglement as well as the normal-mode splitting in a single-atom cavity optomechanical system with intensity-dependent coupling. The system under consideration is formed by a Fabry-Perot cavity with a thin vibrating end mirror and a two-level atom in the Gaussian standing-wave of the cavity mode. We first derive the general form of Hamiltonian describing the tripartite intensity-dependent atom-field-mirror coupling due to the presence of cavity mode structure. We then restrict our treatment to the first vibrational sideband of the mechanical resonator and derive a novel form of tripartite atom-field-mirror Hamiltonian. We show that when the optical cavity is intensely driven one can generate bipartite entanglement between any pair of the tripartite system, and that, due to entanglement sharing, the atom-mirror entanglement is efficiently generated at the expense of optical-mechanical and optical-atom entanglement. We also find that in such a system, when the Lamb-Dicke parameter is large enough one can simultaneously observe the normal mode splitting into three modes

The feasibility of creating a natural habitat for spawning, bony fish in the Caspian Sea in order to preserve biodiversity and genetic risk

The purpose of this study was to investigate the possibility of natural reproduction of indanger fish in the southern Caspian Sea in Tajan, Haraz,Sardabrood and Chalos rivers, and identify suitable habitats for this species in the study area as a genetic reserve.Sampling of physical and chemical parameters of water, macrobenthic invertebrates and fish fauna was conducted seasonaly in each rivers at selected stations from febrary 2010 during one year. Macrobenthic invertebrate sampling were used bySorber sampler and fish was collected by gill net and electroshocker set with a voltage of 1.7 A and 100-300 V. A total of 53 taxa of macrobenticinvertabrateshave been identified in the four mentioned rivers, in which Tajanriverconsisted of 47 taxa with highest richness.20 species of fish were determined in the studied rivers that 6 of them were non-native species.The results showed that the predominant identified fish species were native in the river. The fish species diversity increases as one moves from the headstream towards the estuaries of the two studied Sardabrud and Chalus rivers.The results of this study showed that the relative abundance of fish species resistant to pollution and hard environmental conditions were much more that sensitive species. physicochemical parameters of water such as; water temperature, DO, BOD5, pH, TSS, TDS, EC, turbidity, nutrients, biodiversity index such as Shanon index, EPT, HFBI, EPT/CHIR, nutrition functioning group and present or absent of fish species showed that there are significant decrease in water qualities from upstraem ratio to down stream (For example, in Tajan river water turbidity varied from 0 at station 1 to 333 NTU at station 6, Which is strongly influenced by sand workshops. As well as the activities of a significant impact of fish farming workshop on the Haraz river water quality). The minimum of HFBI index was 2.84 at station 1 and the maximum was recorded at station 5 with 6.01, and there is not any possibility to natural reproduction of migrated species that are dominant and indanger at downstream. Conditions for natural reproduction of this species in the rivers of srdabrood and Chalus there is to some. In Shahid- Rajaei dam the maximum relative abundance of fish species belonged to Capoeta capoeta, Luciobarbus capito and Squalius cephalus, respectively. These species have different age, length and weight stuctures at Shahid- Rajaei dam inhabitant, and the resourval of this dam and it,s upstream have been preparing auch a favorabile condition that seems there are potentioal of introductionand inhabitant of some of the Migratory and indanger fish species such as Barbels, Sturgeon, Alburnus chalcoides and etc. as genetic reserve for biodiversity preservation

Hydrology, Hydrobiology and environmental pollution in the southern of Caspian Sea

The project investigates the relationship between the biological parameters (phytoplankton, zooplankton, Macrobenthic and the comb jelly Mnemiopsis leidyi) and environmental parameters, nutrients and environmental pollutant (oil, pesticides, heavy metals, and detergents) in water and sediment, at the southern part of Caspian Sea in 2009-2010. Sampling was performed in four seasons (spring, summer, autumn and winter) and in eight transects perpendicular to the coast in Astara, Anzali, Sefidroud, Tonekabon, Noshahr, Babolsar, Amir Abad and Turkmen. Samples were collected from depths of 5, 10, 20, 50 and 100 meters and the different layers. The relationship between biological and environmental parameters surveyed through parametric and multivariate methods. Based on the result, the annual mean of environmental parameters and nutrients concentration at euphotic layer such as water temperature, salinity, pH, transparency, DO%, ammonium, nitrate, inorganic nitrogen (DIN), organic nitrogen (DON), inorganic phosphorus (DIP), organic phosphorus (DOP) and soluble silicon (DSi) were 17.82±0.32 (ºC), 11.35±0.10 (g/l), 8.43±0.01 (m), 126±1 (%), 3.76±0.19 (µM), 1.55±0.07 (µM), 4.81±0.13 (µM), 29.88±0.66 (µM), 0.24±0.01 (µM), 0.62±0.02 (µM), 8.22±0.22 (µM), respectively. Meanwhile, annual mean of environmental pollutant such as TPH, OCPs and LAS in water were 12.33±1.76 (µg/l), 2.85.0.90 (µg/l), 0.048±0.003 (mg/l), respectively and for TPH and OCPS in sediment were recorded 33.07±9.36 (µg/g) and 2.64±0.34 (µg/g), respectively. In addition, annual mean of heavy metals such as Ni, Hg, Pb and Cd at water were 4.01±0.01 (µg/l), 0.64±0.01 (µg/l), 15.0±0.1 (µg/l) and ND respectively, and in sediment were obtained 43.77±3.55 (µg/g), 0.13±0.29 (µg/g), 14.14±1.07 (µg/g) and 0.07±0.06 (µg/g), respectively. Abundance annual mean of biological parameters such as phytoplankton, zooplankton and M. leidyi were 143±12 (million cells/m^3), 6548±700 (individuals/m^3) and 86±10 (individuals /m^3) respectively, and for biomass were 548±41 (mg/m^3), 60±9 (mg/m^3), 5.06±0.65 (g/m^3). Abundance and biomass annual mean of macrobenthic were 5970±460 (individuals/m^2) and 44±10 (g/m^2), respectively. The stratification of water column was strongly based on gradient of water temperature and the rule of salinity was low in this area. According to mono and multivariate statistical analysis, the southern of Caspian Sea experienced four seasons without any overlapping based on environmental parameters and nutrients. In 2009-10, the nitrogen concentration was higher than previous years and showed a decrease in the amount of inorganic phosphorus in the study area. Therefore, the system has been lead to phosphorus limitation. No limitations of the DSi in the Caspian ecosystem had caused the dominance of bacillriophyta phylum during spring, autumn and winter. However in summer (highest seasonal mean temperature) which held the most DIP, the cyanophyta was dominant phylum. During spring and winter, the abundance of zooplankton was maximized and conversely the minimum values observed during summer and autumn with growth increasing of M. leidyi. By now, M.leidyi has been preferred the time with highest temperature or salinity during year. However with considering PCA analysis result and high ability of the organism to adaptation, the M.leidyi will probably to growth and reproduce at lower temperature and salinity than now in this area. Result showed that during summer and autumn only abundance of two of six main zooplankton groups namely Copepoda and Cirripedia were noticeable. The other zooplankton groups were low due to high consumption by different predators or were influenced by environmental factors. The dynamics population of M.leidyi is used to consider as first explanation of the Caspian ecosystem happening, however the interaction of different factors such as temperature, salinity, nutrients and predators determine the dynamic of biological parameters. Based on statistical analysis, feeding behavior of zooplankton species was not same in different seasons and was strongly dependent on the phytoplankton structure (species diversity and population). In other words, the classical boundary of phytoplankton species to, edible and suppressed, non-edible and unaffected and finally non-edible, enhanced species was not possible. Copepoda can act as filter-feeder and raptorial-feeder. So Copepoda compare to Cladocera (generally filter- feeder and sometimes raptorial feeder) and Rotifera (mostly suspension feeding and sometimes raptorial feeder) had more chances and opportunities for the achievement food and it support them for dominanane in all seasons. Anthropogenic and eutrophication effect on the structure and function of plankton community and it reflected on ratio of phyto/zoo biomass. Seasonal increasing of different groups of zooplankton were done through their life cycles in 2009-10, but mostly phytoplankton abundance increased several folds than zooplankton populations. This trend made the ratio of phyto/zoo biomass at 10, 4, and14 during spring, summer and autumn, respectively. In summer, with stratification of water column and dominant of Cyanophyta, grazing pressure by herbivores zooplankton was low. However in winter due to the zooplankton population growth, the ratios reached to 11, and declined with 1.3 folds compare to autumn. Because of severe decreasing of zooplankton biomass in 2009-10 compare to years before introduction of M.leidiy in to the Caspian Sea, the ratio of phyto/zoo biomass increased from "less than" 5 "to more than 10" Top-down control of zooplankton grazing on phytoplankton populations was clear in the years before the introduction of M.leidyi in to the Caspian Sea. But in 2009-10 zooplankton Shannon index reduced and phytoplankton Shannon index increased. In other word higher functional diversity at the lower trophic level (phytoplankton) increased the probability of successful defense against top-down control from zooplankton and phytoplankton abundance controled mainly by nutrients materials (down-top control). Seasonal macrobenthos abundance showed the maximum values in summer and minimum in the cold season (winter). The polychaeta had the highest proportion of abundance compare to others main orders (oligochaeta and crustacea). The dominance of deposit feeder species of polychaeta indicates to high level of organic matter in sediment and trophic status of ecosystem. Result of CCA analysis showed that three dominant orders had different behavior respect to environmental and sediments characteristics. The oligochaeta order was directly related to sediments characteristics (TOM) and inverse relationship with environmental parameters at most seasons. In contrast, polychaeta order was linked with environmental parameters in most seasons. Crustacea order was related to the both of them. Two orders of oligochaeta and crustacea were also related directly to OCPs and inverse relationship with TPH and heavy metals. In the other words, the two orders were more affected by TPH and heavy metals in this area. As a last point, increasing of trophic level from oligotrophic to the meso–eutrophic status, an increase of DO% from 105 percent to 120 percent, phytoplankton Shannon index increasing, zooplankton Shannon index decreasing, entrance of the potentially invasive species to the list of dominant phytoplankton species, increasing of phyto/zooplankton biomass ratio from less than 5 to more than 10 and also increasing of deposit feeder species abundance of macrobenthos are some evidences that indicate to disturbance and stress condition of the Caspian Sea

Preventive effects of garlic (Allium sativum) on oxidative stress and histopathology of cardiac tissue in streptozotocin-induced diabetic rats

Since some complications of diabetes mellitus may be caused or exacerbated by an oxidative stress, the protective effects of garlic (Allium sativum) were investigated in the blood and heart of streptozotocin-induced diabetic rats. Twenty-eight male Wistar rats were randomly divided into four groups: control, garlic, diabetic, and diabetic+garlic. Diabetes was induced by intraperitoneal (i.p.) injection of streptozotocin (50 mg/kg) in male rats. Rats were fed with raw fresh garlic homogenate (250 mg/kg) six days a week by gavage for a period of 6 weeks. At the end of the 6th week blood samples and heart tissues were collected and used for determination of glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT), malondialdehyde (MDA) and histological evaluation. Induction of diabetes increased MDA levels in blood and homogenates of heart. In diabetic rats treated with garlic, MDA levels decreased in blood and heart homogenates. Treatment of diabetic rats with garlic increased SOD, GPX and CAT in blood and heart homogenates. Histopathological finding of the myocardial tissue confirmed a protective role for garlic in diabetic rats. Thus, the present study reveals that garlic may effectively modulate antioxidants status in the blood and heart of streptozotocin induced-diabetic rats