Search results for "composition"
showing 10 items of 2675 documents
A decomposition approach for multidimensional knapsacks with family-split penalties
2022
The optimization of Multidimensional Knapsacks with Family-Split Penalties has been introduced in the literature as a variant of the more classical Multidimensional Knapsack and Multi-Knapsack problems. This problem deals with a set of items partitioned in families, and when a single item is picked to maximize the utility, then all items in its family must be picked. Items from the same family can be assigned to different knapsacks, and in this situation split penalties are paid. This problem arises in real applications in various fields. This paper proposes a new exact and fast algorithm based on a specific Combinatorial Benders Cuts scheme. An extensive experimental campaign computational…
Geometry and quasisymmetric parametrization of Semmes spaces
2011
We consider decomposition spaces R 3 /G that are manifold factors and admit defining sequences consisting of cubes-with-handles of finite type. Metrics on R 3 /G constructed via modular embeddings of R 3 /G into a Euclidean space promote the controlled topology to a controlled geometry. The quasisymmetric parametrizability of the metric space R 3 /G×R m by R 3+m for any m ≥ 0 imposes quantitative topological constraints, in terms of the circulation and the growth of the cubes-with-handles, on the defining sequences for R 3 /G. We give a necessary condition and a sufficient condition for the existence of such a parametrization. The necessary condition answers negatively a question of Heinone…
Semi-terminal continua in homogeneous spaces
2016
A semi-terminal continuum Y in a space X is defined by the condition that no two disjoint subcontinua of X intersect both Y and X-Y. Though numerous obvious examples of such continua can be found in arcs, trees and tree-like continua, these examples are related to the non-homogeneity of the space, and having semi-terminal continua in a homogeneous continuum is counter-intuitive. Recently, a large collection of homogeneous spaces with semi-terminal, non-terminal subcontinua has been found. This paper is devoted to studying these spaces and the general structure of homogeneous continua related to the presence of semi-terminal subcontinua.
On approaches for solving computationally expensive multiobjective optimization problems
2016
In this thesis, we consider solving computationally expensive multiobjective optimization problems that take into account the preferences of a decision maker (DM). The aim is to support the DM in identifying the most preferred solution for problems that have several conflicting objectives and when the evaluation of the candidate solutions is time consuming. This is conducted by replacing computationally expensive functions with computationally inexpensive functions, known as surrogates. First, based on a literature survey, we introduce two frameworks, i.e., a sequential and an adaptive framework, based on which surrogate-based methods are classified and compared. We then identify relevant cha…
Denitrifying microbial communities along a boreal stream with varying land-use
2019
Streams have an important role in regulating nitrogen (N) transportation from terrestrial ecosystems to downstream waters. Here, we examined how catchment land-use affects potential denitrification rates and the function and composition of denitrifier communities in boreal stream sediments, using stable isotope incubations and qPCR and 454-pyrosequencing targeted on nirS, nirK and nosZ genes. Although land-use influenced the water chemistry as higher nitrite + nitrate (NO x − ) concentration at the agriculture-affected sampling point, sediment organic matter content was found to be the key factor in regulating potential denitrification rates. However, the abundance as well as the diversity …
Microbial Community Response on Wastewater Discharge in Boreal Lake Sediments
2017
Despite high performance, municipal wastewater treatment plants (WWTPs) still discharge significant amounts of organic material and nitrogen and even microbes into the receiving water bodies, altering physico-chemical conditions and microbial functions. In this study, we examined how nitrified wastewater affects the microbiology of boreal lake sediments. Microbial community compositions were assessed with next generation sequencing of the 16S rRNA gene, and a more detailed view on nitrogen transformation processes was gained with qPCR targeting on functional genes (nirS, nirK, nosZI, nosZII, amoAarchaea, and amoAbacteria). In both of the two studied lake sites, the microbial community compo…
B‐DNA structure and stability: the role of nucleotide composition and order
2022
Abstract We have quantum chemically analyzed the influence of nucleotide composition and sequence (that is, order) on the stability of double‐stranded B‐DNA triplets in aqueous solution. To this end, we have investigated the structure and bonding of all 32 possible DNA duplexes with Watson–Crick base pairing, using dispersion‐corrected DFT at the BLYP‐D3(BJ)/TZ2P level and COSMO for simulating aqueous solvation. We find enhanced stabilities for duplexes possessing a higher GC base pair content. Our activation strain analyses unexpectedly identify the loss of stacking interactions within individual strands as a destabilizing factor in the duplex formation, in addition to the better‐known eff…
A new copper(II) chelate complex with polyamines as fire retardant and epoxy hardener: Synthesis, crystal and electronic structure, and thermal behav…
2020
A new (ethylenediamine-N,N′)-(diethylenetriamine-N,N′,N″)-copper(II) hexafluoridosilicate complex, [Cu(eda)(deta)]SiF6 (1) (eda – ethylenediamine; deta – diethylenetriamine), was synthesized by direct interaction of anhydrous CuSiF6 with polyethylenepolyamine (pepa – H2N[C2H4NH]nH, where n = 1 (eda) and 2 (deta)). The crystals of 1 were characterized by IR spectroscopy and X-ray diffraction. Compound 1 consists of SiF62− discrete anions and [Cu(eda)(deta)]2+ complex cations whose Cu2+ ions are chelated by eda and deta. The coordination polyhedron of Cu(II) atom is an elongated square pyramid which consists of four nitrogen atoms belonging to NH2 groups of eda and NH2 and NH groups of …
Synthesis, structural, and thermal characterization of a new binuclear copper(II) chelate complex bearing an amine-hardener for epoxy resins
2016
A new di(μ-carbonato)bis[aqua(diethylenetriamine)copper(II)] hexahydrate complex, [{Cu(NH(C2H4NH2)2)(H2O)(μ-CO3)}2]⋅6H2O (1), was synthesized by direct interaction of malachite with diethylenetriamine (dien). The crystals of 1 were characterized by X-ray powder diffraction and IR spectra, as well as structurally characterized. Compound 1 consists of [{Cu(dien)(H2O)(μ-CO3)}2] discrete units whose CO32– anions play the role of bridging ligands combining two Cu(II) chelate cores into a centrosymmetric dimer. The elongated octahedral environment of Cu2+ consists of three nitrogens of dien and an oxygen from CO32– at the base of the bipyramid; the two apical positions of such polyhedron are occu…
Ravinnetason ja ojituksen vaikutus suokasvillisuuden monimuotoisuuteen ja lajikoostumukseen
2013
Lajistollisessa monimuotoisuudessa on havaittavissa ajallista ja paikallista vaihtelua, joka on jo vuosisatojen ajan innoittanut ekologeja selvittämään lajirikkauden määrittäviä tekijöitä. Muun muassa pinta-alan, elinympäristön heterogeenisyyden, energian ja resurssien saatavuuden sekä erilaisten häiriöiden on havaittu vaikuttavan lajistolliseen monimuotoisuuteen. Osa monimuotoisuuteen vaikuttavista prosesseista on yhä huonosti tunnettuja, ja yksittäisen tekijän vaikutusta voi olla vaikea tulkita, sillä eri tekijät ovat keskenään vuorovaikutuksessa. Tämän tutkimuksen tavoitteena oli selvittää suokasvillisuusyhteisöjen avulla, vaikuttavatko resurssit tai häiriö (1) yhteisön lajimäärään (alfa…