Egyptian soils are generally characterized by slightly alkaline to alkaline pH values (7.5–8.7) which are mainly due to its dry environment. In arid and semi-arid regions, salts are less concentrated and sodium dominates in carbonate and bicarbonate forms, which enhance the formation of alkaline soils. Alkaline soils have fertility problems due to poor physical properties which adversely affect the growth and the yield of crops. Therefore, this study was devoted to investigating the synergistic interaction of Rhizobium and arbuscular mycorrhizal fungi for improving growth of faba bean grown in alkaline soil. A total of 20 rhizobial isolates and 4 species of arbuscular mycorrhizal fungi (AMF) were isolated. The rhizobial isolates were investigated for their ability to grow under alkaline stress. Out of 20 isolates 3 isolates were selected as tolerant isolates. These 3 rhizobial isolates were identified on the bases of the sequences of the gene encoding 16S rRNA and designated as Rhizobium sp. Egypt 16 (HM622137), Rhizobium sp. Egypt 27 (HM622138) and Rhizobium leguminosarum bv. viciae STDF-Egypt 19 (HM587713). The best alkaline tolerant was R. leguminosarum bv. viciae STDF-Egypt 19 (HM587713). The effect of R. leguminosarum bv. viciae STDF-Egypt 19 and mixture of AMF (Acaulospora laevis, Glomus geosporum, Glomus mosseae and Scutellospora armeniaca) both individually and in combination on nodulation, nitrogen fixation and growth of Vicia faba under alkalinity stress were assessed. A significant increase over control in number and mass of nodules, nitrogenase activity, leghaemoglobin content of nodule, mycorrhizal colonization, dry mass of root and shoot was recorded in dual inoculated plants than plants with individual inoculation. The enhancement of nitrogen fixation of faba bean could be attributed to AMF facilitating the mobilization of certain elements such as P, Fe, K and other minerals that involve in synthesis of nitrogenase and leghaemoglobin. Thus it is clear that the dual inoculation with Rhizobium and AMF biofertilizer is more effective for promoting growth of faba bean grown in alkaline soils than the individual treatment, reflecting the existence of synergistic relationships among the inoculants.

Egyptian soils are generally characterized by slightly alkaline to alkaline pH values (7.5–8.7) which are mainly due to its dry environment. In arid and semi-arid regions, salts are less concentrated and sodium dominates in carbonate and bicarbonate forms, which enhance the formation of alkaline soils. Alkaline soils have fertility problems due to poor physical properties which adversely affect the growth and the yield of crops. Therefore, this study was devoted to investigating the synergistic interaction of Rhizobium and arbuscular mycorrhizal fungi for improving growth of faba bean grown in alkaline soil. A total of 20 rhizobial isolates and 4 species of arbuscular mycorrhizal fungi (AMF) were isolated. The rhizobial isolates were investigated for their ability to grow under alkaline stress. Out of 20 isolates 3 isolates were selected as tolerant isolates. These 3 rhizobial isolates were identified on the bases of the sequences of the gene encoding 16S rRNA and designated as Rhizobium sp. Egypt 16 (HM622137), Rhizobium sp. Egypt 27 (HM622138) and Rhizobium leguminosarum bv. viciae STDF-Egypt 19 (HM587713). The best alkaline tolerant was R. leguminosarum bv. viciae STDF-Egypt 19 (HM587713). The effect of R. leguminosarum bv. viciae STDF-Egypt 19 and mixture of AMF (Acaulospora laevis, Glomus geosporum, Glomus mosseae and Scutellospora armeniaca) both individually and in combination on nodulation, nitrogen fixation and growth of Vicia faba under alkalinity stress were assessed. A significant increase over control in number and mass of nodules, nitrogenase activity, leghaemoglobin content of nodule, mycorrhizal colonization, dry mass of root and shoot was recorded in dual inoculated plants than plants with individual inoculation. The enhancement of nitrogen fixation of faba bean could be attributed to AMF facilitating the mobilization of certain elements such as P, Fe, K and other minerals that involve in synthesis of nitrogenase and leghaemoglobin. Thus it is clear that the dual inoculation with Rhizobium and AMF biofertilizer is more effective for promoting growth of faba bean grown in alkaline soils than the individual treatment, reflecting the existence of synergistic relationships among the inoculants.

We report here on the planktonic foraminiferal faunas of the Paleocene-Eocene boundary interval between 21.15 m (Tarawan Chalk/Esna Shale 1 boundary; basal Zone P4c) and the basal part of the MahmiyaMember of Esna Shale Unit 3 (~5-6 m; Zone E2; Lower Eocene) in the Dababiya Quarry Corehole (DQC). The sequential lower/initial late Paleocene appearance of several morozovellid and acarininid taxa in the ~ 10 minterval from the top of the Tarawan Chalk (21.15 m) to the base of the lithologically distinct Dababiya Quarry Member (11.82 m), the presence of the characteristic PETM excursion planktonic fauna (Acarinina sibaiyaensis, Ac. africana and Morozovella allisonensis) within the DBQ Beds (11.82 m to 9.5 m), the “Eocene flood”of planktonic faunal elements and the LO/initial appearance of Pseudohastigerna wilcoxensis in Bed 5 of the DBQ Beds mirrors our earlier observations in the nearby Dababiya Quarry outcrops and makes precise correlation between the two sections possible.

Following a decade of studies in search of appropriate criteria for selecting/defining and characterizing/correlating an optimum location/level for a GSSP, the Working Group on the Paleocene/Eocene boundary selected the 1.65 m level at the base of Section DBH in the Dababiya Quarry, on the east bank of the Nile River, about 35 km south of Luxor, Egypt (text-figs. 1-3). This level is correlative with the onset of a Carbon Isotope Excursion (CIE) that was denoted as the primary criterion for recognition and correlation of the Eocene GSSP. This (lithologic) definition was formalized (Aubry et al. 2007) following ratification by the IUGS at the 33rd IGC (Florence, August 2004). The basal Bed 1, the oldest bed of the Eocene Epoch, is a dark gray clay, and one of five characteristic beds (named the “Dababiya Quarry Beds”, Ouda and Aubry, eds., 2003, text-figs. 4a and b, this paper) that outcrop through extensive areas of the Middle East. These five beds (~3.5 m-thick in the Dababiya GSSP section) that occur in an otherwise monotonous lithology of shales (~120 m in the quarry) are indicative of a major disruption that affected the Earth system at the time of their deposition. Elsewhere, this disruption has left its mark in the sedimentary record, in most instances with abrupt changes in lithology.

The concepts of a-continuity and ca-continuity are considered and studied in fuzzifying topology and by making use of these concepts, some decompositions of fuzzy continuity are introduced. It is proved that the family of all a-sets in fuzzifying topology may not be a fuzzifying topology