Romanian Academy

About: Romanian Academy is a archive organization based out in Bucharest, Romania. It is known for research contribution in the topics: Population & Nonlinear system. The organization has 3662 authors who have published 10491 publications receiving 146447 citations. The organization is also known as: Academia Română & Societatea Literară Română.

Alternative utilization of algal biomass ( Ulva sp.) loaded with Zn(II) ions for improving of soil quality

Abstract: This study focused on the alternative utilization of marine algal biomass (Ulva sp.), first as biosorbent for the removal of Zn(II) ions from aqueous solution and then as fertilizer for the improvement of soil quality, by its supplementation with Zn(II) as essential microelement. The biosorption experiments performed in batch systems at room temperature (22 ± 0.5 °C) showed that maximum removal efficiency of Zn(II) onto marine algae biomass is obtained in an initial solution with pH of 5.5, 8.0 g L−1 biosorbent dose, and 2 h of contact time. Under these conditions, the biosorption capacity reached 29.63 mg Zn(II) g−1 biomass. The desorption experiments have indicated that Zn(II) can be quantitatively released from loaded biomass using solutions of common inorganic salts and suggests the possibility of using Zn(II)-loaded biomass as fertilizer. This possibility was tested using an aric antrosol sample. After 8 weeks of treatment with Zn(II)-loaded biomass, the Zn(II) content in the soil sample increased over four times. Therefore, the marine algae loaded with Zn(II) can be a viable alternative of fertilizers and can be successfully used to increase soil quality.

An universality result for a (mem)brane calculus based on mate/drip operations

Abstract: Operations with membranes are essential both in brane calculi and in membrane computing. In this paper we take four basic operations from brane calculi, pino, exo, mate, drip, we express them in terms of the membrane computing formalism, and then we investigate the computing power of the P systems using the mate, drip operations as unique evolution rules. All operations are controlled by – and make evolve – multisets of protein-objects embedded in the membranes themselves (not contained in the compartments of the cell, as standard in membrane computing; all compartments delimited by membranes are here empty). Somewhat surprisingly, for systems which use the mate, drip operations we obtain the Turing completeness. The power of P systems based on other operations remains to be investigated.

Response of the Upper/Middle Atmosphere to Coronal Holes and Powerful High‐Speed Solar Wind Streams in 2003

Abstract: High-speed solar wind streams originating from large coronal holes reached a maximum in 2003 during the descending phase of solar cycle 23. At the same time, magnetic activity (as indicated by the aa index) reached the highest levels of the last four solar cycles. The rotation of active regions behind the limb and the appearance of coronal holes contribute to a decrease in EUV radiation at Earth prior to the arrival of a high-speed stream. This leads to a cooling of the upper atmosphere and a decrease in the total electron content (TEC). Changes in ΣO/N 2 are also expected but contributions from local time and seasonal changes as the satellite orbit precesses during a solar rotation will require additional simulations to unravel. These systematic changes are intriguing because auroral disturbances expand further equatorward in latitude and deeper in altitude as F10.7 decreases. Disturbances in nitric oxide (NO), the dominant cooling agent in the upper atmosphere, continue for the duration of the high-speed stream activity and may not fully recover before the next stream hits. These disturbed conditions might actually represent the most common state of the upper atmosphere in years of strong recurrent high-speed streams. Finally, the persistent source of thermospheric NO in the auroral region during high-speed streams, when combined with favorable meteorological conditions in the dark polar middle atmosphere, results in significant enhancements in stratospheric NO X . These correspond to increases in stratospheric ozone loss, establishing a previously unexplored link between high-speed streams and stratospheric variability.

The Structure of F-Pure Rings

Abstract: For a reduced F-finite ring R of characteristic p >0 and q=p^e one can write R^{1/q} = R^{a_q} \oplus M_q, where M_q has no free direct summands over R. We investigate the structure of F-finite, F-pure rings R by studying how the numbers a_q grow with respect to q. This growth is quantified by the splitting dimension and the splitting ratios of R which we study in detail. We also prove the existence of a special prime ideal P(R) of R, called the splitting prime, that has the property that R/P(R) is strongly F-regular. We show that this ideal captures significant information with regard to the F-purity of R.