Search results for "Minimum"
showing 10 items of 327 documents
Activity–Bioavailability balance in Oral Drug Development for a Selected Group of 6‐Fluoroquinolones
2002
Abstract A nomogram is proposed to select the best candidate in drug development studies with quinolones and is intended to substitute other possible models. The nomogram is referred to as an activity–bioavailability balance (ABB) because it includes the following two criteria: ABB= 1 / gm MIC ( drug candidate ) 1 /gm MIC ( ciprofloxacin ) · F calc \( drug candidate \) F calc ( ciproflaxacin ) . The in vitro activity of a group of 4′ N ‐alkyl‐ciprofloxacin derivatives was determined together with that of ciprofloxacin, initially against some reference strains and subsequently against 159 clinical isolates of eight selected species. The inverse of the geometric mean of the lowest concentrati…
Azacoccones F-H, new flavipin-derived alkaloids from an endophytic fungus Epicoccum nigrum MK214079.
2020
Abstract Three new flavipin-derived alkaloids, azacoccones F-H (1–3), along with six known compounds (4–9) were isolated from the endophytic fungus Epicoccum nigrum MK214079 associated with leaves of Salix sp. The structures of the new compounds were established by analysis of their 1D/2D nuclear magnetic resonance (NMR) and high-resolution electrospray ionization mass spectroscopy (HRESIMS) data. The absolute configuration of azacoccones F-H (1–3) was determined by comparison of experimental electronic circular dichroism (ECD) data with reported ones and biogenetic considerations. Epicocconigrone A (4), epipyrone A (5), and epicoccolide B (6) exhibited moderate antibacterial activity again…
Tetrahydroanthraquinone Derivatives from the Endophytic Fungus Stemphylium globuliferm
2015
Four new tetrahydroanthraquinone derivatives, namely, dihydroaltersolanol B (1), dihydroaltersolanol C (2), and the atropisomers acetylalterporriol D (3) and acetylalterporriol E (4), were obtained from the endophytic fungus Stemphylium globuliferum, which was isolated from Juncus acutus growing in Egypt. The structures of the new compounds were unambiguously elucidated on the basis of one- and two-dimensional NMR spectroscopy, as well as by high-resolution mass spectrometry and electronic circular dichroism (ECD) spectroscopy. In addition, seven known anthraquinone derivatives 5–11 were isolated and identified on the basis of their spectral characteristics and by comparison with literature…
Comparison of the activity of antifungal hexapeptides and the fungicides thiabendazole and imazalil against postharvest fungal pathogens
2003
8 pages, 2 figures, 3 tables.-- PMID: 14623382 [PubMed].-- Printed version published Dec 31, 2003.
Bayesian versus data driven model selection for microarray data
2014
Clustering is one of the most well known activities in scientific investigation and the object of research in many disciplines, ranging from Statistics to Computer Science. In this beautiful area, one of the most difficult challenges is a particular instance of the model selection problem, i.e., the identification of the correct number of clusters in a dataset. In what follows, for ease of reference, we refer to that instance still as model selection. It is an important part of any statistical analysis. The techniques used for solving it are mainly either Bayesian or data-driven, and are both based on internal knowledge. That is, they use information obtained by processing the input data. A…
Política económica y redistribución: hacia una nueva arquitectura “pre-distributiva” de la política de rentas
2020
El presente trabajo diseña una política de rentas que podríamos llamar “pre-distributiva”. Su principal objetivo es describir la arquitectura de una política de rentas amplia, que tendría, básicamente, tres pilares: a) el reforzamiento de la capacidad redistributiva de la negociación colectiva, b) el establecimiento de una “norma salarial redistributiva” coordinada a nivel europeo y c) el aumento del Salario Mínimo Interprofesional. Dicha política de rentas podría contribuir a una distribución más equitativa de las rentas primarias del trabajo.
On the Low-Dimensional Steiner Minimum Tree Problem in Hamming Metric
2011
It is known that the d-dimensional Steiner Minimum Tree Problem in Hamming metric is NP-complete if d is considered to be a part of the input. On the other hand, it was an open question whether the problem is also NP-complete in fixed dimensions. In this paper we answer this question by showing that the problem is NP-complete for any dimension strictly greater than 2. We also show that the Steiner ratio is 2 - 2/d for d ≥ 2. Using this result, we tailor the analysis of the so-called k-LCA approximation algorithm and show improved approximation guarantees for the special cases d = 3 and d = 4.
The node-depth encoding
2008
The node-depth encoding has elements from direct and indirect encoding for trees which encodes trees by storing the depth of nodes in a list. Node-depth encoding applies specific search operators that is a typical characteristic for direct encodings. An investigation into the bias of the initialization process and the mutation operators of the node-depth encoding shows that the initialization process has a bias to solutions with small depths and diameters, and a bias towards stars. This investigation, also, shows that the mutation operators are unbiased. The performance of node-depth encoding is investigated for the bounded-diameter minimum spanning tree problem. The results are presented f…
Orientation matters
2008
The optimal communication spanning tree (OCST) problem is a well known $\mathcal{NP}$-hard combinatorial optimization problem which seeks a spanning tree that satisfies all given communication requirements for minimal total costs. It has been shown that optimal solutions of OCST problems are biased towards the much simpler minimum spanning tree (MST) problem. Therefore, problem-specific representations for EAs like heuristic variants of edge-sets that are biased towards MSTs show high performance.In this paper, additional properties of optimal solutions for Euclidean variants of OCST problems are studied. Experimental results show that not only edges in optimal trees are biased towards low-…
An algorithm for the Rural Postman problem on a directed graph
1986
The Directed Rural Postman Problem (DRPP) is a general case of the Chinese Postman Problem where a subset of the set of arcs of a given directed graph is ‘required’ to be traversed at minimum cost. If this subset does not form a weakly connected graph but forms a number of disconnected components the problem is NP-Complete, and is also a generalization of the asymmetric Travelling Salesman Problem. In this paper we present a branch and bound algorithm for the exact solution of the DRPP based on bounds computed from Lagrangean Relaxation (with shortest spanning arborescence sub-problems) and on the fathoming of some of the tree nodes by the solution of minimum cost flow problems. Computation…