Biodiversity of benthic invertebrates in Aras River

Benthic invertebrate species and their change was studied in Aras River during a hydro- biological research on the middle and terminal parts of Aras River that spanned the years 1995-1996 and 2005-2006. We found 91 species of benthic invertebrates of which 85 species were identified during 1995-1996 and 49 species during 2005-2006. The highest rate of biodiversity was seen in molluscs with 19 species and chironomid larvae with 17 species. Forty-two species had wide distribution and the remaining occurred only in special habitats. The biomass of invertebrates reduced from the upper reach of the river to the middle and lower reaches because of the changes in river bed from soil to sand. It is concluded that the formation of different habitats in different sections of the Aras River has a crucial role in the change observed in biodiversity of the benthic invertebrates

Modification of cytogenetic and physiological effects of space flight factors by biologically active compounds

Physiological and cytogenetic changes in the Welsh onion plants induced by a short (82 days) and long term (522 days) space flight are expressed in decrease of seed germination, inhibition of stem growth, depression of cell division in root meristem, and increase in the number of structural chromosome rearrangements. The treatment of such plants with solutions of a-tocopherol, auxin, and kinetin decreased the level of chromosome aberrations to the control one and normalized cell divisions and growth partly or completely

Fluctuation in density of ciliates in Bukan dam reservoir, Zarrinehrud, Iran

The abundance and species composition of ciliates were analyzed in the Bukan Dam Reservoir (West Azerbaijan, Iran) from January to December 2008. Surface water samples were collected at monthly intervals from the middle (Stations 1 and 3) and shallow (Stations 2 and 4) areas of the lake. Three samples were taken in the water column using a 5-litre sampler. Totally 30 liters water was collected, 200 ml of which was fixed immediately with 8.6 ml of a saturated HgCl2 solution and stained with 0.04% bromophenol blue. Three subsamples were counted in a 5-ml chamber and examined with a microscope (100 x) as well as Chlorophyll a and a few ecological parameters such as dissolved oxygen, pH, transperancy and water temperature were measured. Totally 50 ciliates species were found in Bukan Dam Reservoir. Regarding the density, a high-density period was detected from January to April with a mean density of 2.86 x 103 cells.l-1 Ciliata at stations 1 and 3 and 4.16 x 103 cells.l-1 at stations 2 and 4. The high density of ciliate in summer may be due to the increase in the density of bacteria and moderate metazooplankton as a result of the appearance of non-edible algae . The ciliata occurring at the highest densities were Coleps tessellates, Didinium nasutum, Paradileptus elephantinus, Stentor polymorphus, Zosterograptus labiatus, Paramecium bursaria, Cyclidium citrullus, Vorticella campanula, Halteria grandinella and Aspidisca costata. The maximum and minimum chlorophyll a values observed at the reservoir water were 10.39 µg.l-l and 1.0 µg.l-l being obtained in May and Octobor respectively

Scientific rationale for the use of low-intensity sprinkling systems in mountain irrigated agriculture in Azerbaijan

The results of the study revealed that the mismatch intensity rain rate of water absorption into the soil formation of a surface relief and soil erosion, uneven and zakiraliyev soaking imperfection open irrigation system at a superficial irrigation, the need for different irrigation methods in the growing and not growing periods, low coefficient land utilization, high cost of irrigation and other features are, to a certain extent in conflict with the requirements of watering cultivated with techniques for / of crops in an area at the deep groundwater

Static quantities of the W boson in the SU_L(3) X U_X(1) model with right-handed neutrinos

The static electromagnetic properties of the $W$ boson, $\Delta \kappa$ and $\Delta Q$, are calculated in the SU_L(3)} \times U_X(1) model with right-handed neutrinos. The new contributions from this model arise from the gauge and scalar sectors. In the gauge sector there is a new contribution from a complex neutral gauge boson $Y^0$ and a singly-charged gauge boson $Y^\pm$. The mass of these gauge bosons, called bileptons, is expected to be in the range of a few hundreds of GeV according to the current bounds from experimental data. If the bilepton masses are of the order of 200 GeV, the size of their contribution is similar to that obtained in other weakly coupled theories. However the contributions to both $\Delta Q$ and $\Delta \kappa$ are negligible for very heavy or degenerate bileptons. As for the scalar sector, an scenario is examined in which the contribution to the $W$ form factors is identical to that of a two-Higgs-doublet model. It is found that this sector would not give large corrections to $\Delta \kappa$ and $\Delta Q$.Comment: New material included. Final version to apppear in Physical Review

Inclusive search for same-sign dilepton signatures in pp collisions at root s=7 TeV with the ATLAS detector

An inclusive search is presented for new physics in events with two isolated leptons (e or mu) having the same electric charge. The data are selected from events collected from p p collisions at root s = 7 TeV by the ATLAS detector and correspond to an integrated luminosity of 34 pb(-1). The spectra in dilepton invariant mass, missing transverse momentum and jet multiplicity are presented and compared to Standard Model predictions. In this event sample, no evidence is found for contributions beyond those of the Standard Model. Limits are set on the cross-section in a fiducial region for new sources of same-sign high-mass dilepton events in the ee, e mu and mu mu channels. Four models predicting same-sign dilepton signals are constrained: two descriptions of Majorana neutrinos, a cascade topology similar to supersymmetry or universal extra dimensions, and fourth generation d-type quarks. Assuming a new physics scale of 1 TeV, Majorana neutrinos produced by an effective operator V with masses below 460 GeV are excluded at 95% confidence level. A lower limit of 290 GeV is set at 95% confidence level on the mass of fourth generation d-type quarks

Measurement of the top quark-pair production cross section with ATLAS in pp collisions at \sqrt{s}=7\TeV

A measurement of the production cross-section for top quark pairs(\ttbar) in $pp$ collisions at \sqrt{s}=7 \TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two different topologies: single lepton (electron $e$ or muon $\mu$) with large missing transverse energy and at least four jets, and dilepton ($ee$, $\mu\mu$ or $e\mu$) with large missing transverse energy and at least two jets. In a data sample of 2.9 pb-1, 37 candidate events are observed in the single-lepton topology and 9 events in the dilepton topology. The corresponding expected backgrounds from non-\ttbar Standard Model processes are estimated using data-driven methods and determined to be $12.2 \pm 3.9$ events and $2.5 \pm 0.6$ events, respectively. The kinematic properties of the selected events are consistent with SM \ttbar production. The inclusive top quark pair production cross-section is measured to be \sigmattbar=145 \pm 31 ^{+42}_{-27} pb where the first uncertainty is statistical and the second systematic. The measurement agrees with perturbative QCD calculations.Comment: 30 pages plus author list (50 pages total), 9 figures, 11 tables, CERN-PH number and final journal adde