Algebraic string bracket as a Poisson bracket

14 PagesInternational audienceIn this paper we construct a Lie algebra representation of the algebraic string bracket on negative cyclic cohomology of an associative algebra with appropriate duality. This is a generalized algebraic version of the main theorem of [AZ] which extends Goldman's results using string topology operations.The main result can be applied to the de Rham complex of a smooth manifold as well as the Dolbeault resolution of the endomorphisms of a holomorphic bundle on a Calabi-Yau manifold

Leaf water potential, photosynthetic pigments and compatible solutes alterations in four grape cultivars under salinity

A hydroponic culture experiment was conducted to investigate the effects of different concentrations (0, 25, 50 and 100 mM) NaCl on own-rooted table grape (Vitis vinifera L.) cultivars (red 'Rishbaba', red 'Sahebi', 'Dastarchin' and red 'Sultana') under greenhouse conditions. Cultivars were evaluated for growth analysis leaf area, leaf water potential and the chlorophyll a, b and carotenoid contents in relation to proline and soluble sugars accumulation. Salinity treatments caused a growth reduction (P ≤ 0.05) in all the cultivars. Also leaf water potential and chlorophyll a, b contents decreased whereas carotenoid, proline and soluble sugars increased with increasing NaCl concentration. 'Dastarchin' and red 'Sultana' showed the salt- sensitivity, the highest loss of growth, leaf water potential and chlorophyll content and the lowest accumulation of carotenoids, proline and soluble sugars. Also salt stress significantly (P < 0.001) increased the rate of lipid peroxidation in the all cultivars particularly in 'Dastarchin' and red 'Sultana'. The increase in malondialdehyde content indicated that salinity induced oxidative stress. There was a significant negative correlation between leaf water potential and NaCl concentrations (r2: -0.781, p < 0.001). A positive correlation was also found between lamina proline contents and NaCl concentrations (r2: +0.964, p < 0.001) for all salinity treatments. Considering overall results red 'Rishbaba' and red 'Sahebi' showed higher capacity to tolerate salinity when compared to 'Dastarchin' and red 'Sultana'.

Short term response of grapevine grown hydroponically to salinity: Mineral composition and growth parameters

The response of hydroponically grown four ownrooted table grape (Vitis vinifera L.) cultivars ('Red Rishbaba', 'Red Sahebi', 'Dastarchin' and 'Red Sultana') to different salt concentrations (0, 25, 50 and 100 mM NaCl) was studied under greenhouse condition. Growth parameters, total chlorophyll (a+b) and proline contents were determined in leaves and roots. Cl-, Na+, K+ and NO3 - concentrations were measured in lamina, petiole, stem and root. Shoot growth, total dry weight, total leaf chlorophyll (a+b), NO3 --N and K+ contents were significantly reduced (P≤0.05) under NaCl stress, whereas proline, Cl- and Na+ accumulation increased significantly with increasing salinity. 'Red Rishbaba' and 'Red Sahebi' showed a less decrease in total leaf chlorophyll, K+ and NO3 - contents, while proline accumulation in these cultivars was higher than that of 'Dastarchin' and 'Red Sultana'. Also, shoots of 'Red Sahebi' and 'Red Rishbaba' accumulated lower Cl- and Na+ than other cultivars. In conclusion, the overall results showed that 'Red Rishbaba' and 'Red Sahebi' were more tolerant than 'Dastarchin' and 'Red Sultana'.

Effect of mycorrhiza symbiosis on the Nacl salinity in Sorghum bicolor

In order to determine mycorrhizal symbiosis on the Nacl salinity tolerance in Sorghum bicolor (aspydfyd cultivar), an experiment with two factors was done in Damghan Islamic Azad University laboratory (Iran) in 2007. The first factor with two levels (mycorihizal and non-mycorihizal) and second factor with six levels Nacl concentration of (0, 50, 100, 150, 200 and 250 Mmol) were examined in a random design with three replication in sand environment for 15 weeks. The measurements were the absorption of K, Na, P, N, plant growth, tolerance for different salinity concentrations and traits such as stem and root dry weight and the length of stem. The results showed that the dry weight and stem height in M plants were higher than NM plants. The increase in Nacl concentration decreased the stem height in both groups. However, there was no significant different in root dry weight. The measurement of elements in different organs showed that with increase in Nacl concentration, there would be a significant decrease in N, P, K absorption. But Na absorption increase is more in lower Nacl concentration. Generally, the amount of N, P, K in M plant organs is more than NM plant organs. The result of the experiment showed that mycorrhizal symbiosis is not only effective on element absorption, but also in plant growth and to some extent on salinity tolerance of the plant. So it will be suggested that mycorrhizal be used in salty soils with high Nacl for Sorghum bicolor.Key words: Sorghum, mycorrhizal, salinity, symbiosis, tolerance

Modeling of thermal pollution in coastal area and its economical and environmental assessment

The Persian Gulf is one of the aquatic ecosystems which has recently faced with different pollutions. Cooling water discharges due to various industries such as power plants can cause important disorders on present ecosystem balance because of its high temperature. Obviously, due to thermal pollution, a great number of aquatic creatures face with a new situation that they can not tolerate. Thermal pollution leads to their migration, creates a potential for new coming species which in turn can thoroughly change the marine ecosystem feature. The other impacts of this phenomenon are: disorders in reproduction, nourishment and other biological habits. In this research, thermal pollution due to Bandar Abbas Thermal Power Plant (BATP) development plan was modeled using MIKE21 software. In order to avoid a decrease on the power plant efficiency in development plan, the distance between inlet and outlet was determined by comparing the results of different scenarios and economical aspects. After determining the distance between inlet and outlet, the water temperature in the coastal area was compared with standards of Iranian Department of the Environment (DOE). The model results represent that the water temperature, in Bandar Abbas coastal area, exceeds than the permissible limit (3 °C) in a distance equal to 200 m. far from the discharging location, and in order to reduce its harmful impacts, some suggestions are made to reduce the associated thermal pollution

Virtual water highway: water use efficiency in global food trade

International audienceAmid an increasing water scarcity in many parts of the world, virtual water trade as both a policy instrument and practical means to balance the regional, national and global water budget has received much attention in recent years. Built upon the knowledge of virtual water accounting in the literature, this study examines the efficiency of the resource use embodied in the global virtual water trade from the perspectives of exporting and importing countries. Different characteristics between "green" and "blue" virtual water corresponding to rainfed and irrigated agriculture are elaborated. The investigation reveals that the virtual water flows primarily from countries of high water productivity to countries of low water productivity, generating a global saving of water resources. Meanwhile, the domination of green virtual water in the total virtual water trade constitutes low opportunity costs and environmental impacts as opposed to blue virtual water. The results suggest efficiency gains in the global food trade in terms of water resource utilization. The study raises awareness of negative impacts of increasing reliance on irrigation for food production in many countries, including food exporting countries. The findings of the study call for a greater emphasis on rainfed agriculture to improve global food security and environmental sustainability

Spinor stochastic resonance

International audienceWe report on noise-induced spin ordering in a collective quasiparticle system: spinor stochastic resonance. Synergetic interplay of a polarization-modulated signal and a polarization noise allows us to switch coherently between the two metastable states of a microcavity-polariton spin bistable system. Spinor stochastic resonance is demonstrated in a zero-dimensional GaAs based microcavity. The resonance behaviors of both the spin amplification and the signal-to-noise ratio are experimentally evidenced as a function of the noise strength for different amplitude modulations. They are theoretically reproduced using a spinor Gross-Pitaevskii equation driven by a randomly polarized laser field

Analyses of impacts of China's international trade on its water resources and uses

This study provides an insight into the impact of China's international trade of goods and services on its water resources and uses. Virtual water flows associated with China's international trade are quantified in an input-output framework. The analysis is scaled down to the sectoral and provincial levels to trace the origins and destinations of virtual water flows associated with the international trade. The results show that China is a net virtual water exporter of 4.8 × 10<sup>10</sup> m<sup>3</sup> yr<sup>−1</sup>, accounting for 2.1% of its renewable water resources and 8.6% of the total water use. Water scarce regions tend to have higher percentages of virtual water export relative to their water resources and water uses. In the water scarce Huang-Huai-Hai region, the net virtual water export accounts for 8.0% of the region's water resources and 11.3% of its water uses. For individual sectors, major net virtual water exporters are those where agriculture provides raw materials in the initial process of the production chain. The results suggest that China's economic gains from being a world "manufacture factory" have come at a high cost to its water resources

Effect of a noisy driving field on a bistable polariton system

International audienceWe report on the effect of noise on the characteristics of the bistable polariton emission system. The present experiment provides a time-resolved access to the polariton emission intensity. We evidence the noise-induced transitions between the two stable states of the bistable polaritons. It is shown that the external noise specifications, intensity and correlation time, can efficiently modify the polariton Kramers time and residence time. We find that there is a threshold noise strength that provokes the collapse of the hysteresis loop. The experimental results are reproduced by numerical simulations using Gross-Pitaevskii equation driven by a stochastic excitation

Distribution of metal(loid)s in particle size fraction in urban soil and street dust: influence of population density

Assessment of street dust is an invaluable approach for monitoring atmospheric pollution. Little information is available on the size distribution of contaminants in street dusts and urban soils and it is not known how the population density would influence them. This research was carried out to assess the size distribution of trace metal(loid)s in street dust and urban soil, and to understand how population density might influence the size-resolved concentration of metal(loid)s. Three urban areas with a high (HD), medium (MD) and low population density (LD) and a natural area (NA) were selected, and urban soil and street dust sampled. They were fractionated into 8 size fractions: 2000-850, 850-180, 180-106, 106-50, 50-20, 20-10, 10-2, and < 2 µm. The concentration of Pb, Zn, Cu, Cd, Cr, Ni, As, and Fe was determined and enrichment factor and grain size fraction loadings were computed. The results indicated that the concentration of Pb, Zn, Cu, Cd, Cr were highly size dependent, particularly for particles < 100 µm, especially for street dust. Low concentrations of Ni and As in street dust and urban soil were size and population density independent. Higher size dependency of the metals concentration and the higher degree of elemental enrichment in the street dust fractions than the urban soils indicate higher contribution of human induced pollution to the dust. Findings also confirm the inevitability of size fractionation when soils or dusts are environmentally assessed, particularly in moderately to highly polluted areas. Otherwise, higher concentrations of certain pollutants in fine-sized particles might be overlooked leading to inappropriate decisions for environmental remediation.Este artículo fue financiado por las universidades Isfahan University of Technology y Shahrood University of Technology (Irán) a través de las estancias de los profesores Khademi y Abbaspour, así como por la Fundación Séneca de la Comunidad Autónoma de la Región de Murcia, con el proyecto de referencia 15380/PI/10