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.

Exact Controllability of the Superlinear Heat Equation

Abstract: The exact internal and boundary controllability of parabolic equations with superlinear nonlinearity is studied.

The Impact of COVID-19 Crisis upon the Consumer Buying Behavior of Fresh Vegetables Directly from Local Producers. Case Study: The Quarantined Area of Suceava County, Romania.

Abstract: The present paper intends to address the impact of COVID-19 crisis upon the consumer buying behavior of fresh vegetables directly from local producers as observed 30 days later, after enforcing the state of emergency in Romania within a well-defined area, namely, the quarantined area of Suceava. The study relies on the interpretation of answers received from the quarantined area (N = 257) to a questionnaire applied online nationwide. The starting point of this paper is the analysis of the sociodemographic factors on the purchasing decision of fresh vegetables directly from local producers before declaring the state of emergency in Romania (16 March 2020). Further research has been conducted by interpreting the changes triggered by the COVID-19 crisis on the purchasing intention of such products before and after the end of the respective crisis. The aim of this scientific investigation relies on identifying the methods by which these behavioral changes can influence the digital transformation of short food supply chains.

Hypersurface complements, Milnor fibers and higher homotopy groups of arrangements

Abstract: We describe a new relation between the topology of hypersurface complements, Milnor fibers and degree of gradient mappings. In particular we show that any projective hypersurface has affine parts which are bouquets of spheres. The main tools are the polar curves and the affine Lefschetz theory developped by H. Hamm, D.T. L\^e and A. N\'emethi. In the special case of the hyperplane arrangements, we strengthen some results due to Orlik and Terao (see Math. Ann. 301(1995)) and obtain the minimality of hyperplane arrangements (see Randell math.AT/0011101 for another proof of this result). This is then used to compute some higher homotopy groups of hyperplane arrangements using the ideas from Papadima-Suciu, see math.AT/0002251. The second version contains applications of the above ideas to the polar Cremona transformations and gives a positive answer to Dolgachev's Conjecture (see Michigan Math. J. 48 (2000), volume dedicated to W. Fulton). The third version corrects some errors and provides new applications.

Study of quaternary ‘onium’ salts grafted on polymers: antibacterial activity of quaternary phosphonium salts grafted on ‘gel-type’ styrene–divinylbenzene copolymers

Abstract: This paper deals with the synthesis and characterization of compounds with antibacterial activity: quaternary phosphonium salts grafted on macromolecular supports by polymer-analogous reactions. The products were proved to have antibacterial activity against Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa. A great advantage was that the active species grafted on insoluble carriers could be used in repeated cycles, only needing sterilization prior to use.

Reduction of topological stable rank in inductive limits of c*-algebras

Abstract: We consider inductive limits A of sequences A 1 →A 2 →... of finite direct sums of C * -algebras of continuous functions from compact Hausdorff spaces into full matrix algebras. We prove that A has topological stable rank (tsr) one provided that A is simple and the sequence of the dimensions of the spectra of A i is bounded. For unital A, tsr(A)=1 means that the set of invertible elements is dense in A. If A is infinite dimensional, then the simplicity of A implies that the sizes of the involved matrices tend to infinity, so by general arguments one gets tsr(A i )≤2 for large enough is whence trsr(A)≤2. The reduction of tsr from two to one requires arguments which are strongly related to this special class of C * -algebras