Search results for "element"
showing 10 items of 13601 documents
Magneto-structural correlations in discrete $Mn^{II}‐W^V$ cyano‐bridged assemblies with polyimine ligands
2010
We present the magneto-structural correlations for two novel discrete cyano-bridged assemblies based on cationic complexes of manganese(II) with diimine ligands and octacyanotungstate(V) ions. The crystal structure of [Mn II (terpy)(dmf)-(H 2 O) 2 ][Mn II (terpy)(H 2 O)(dmf)(μ-NC)W V (CN) 7 ] 2· 6H 2 O (1) (terpy = 2,2';6',2"-terpyridine, dmf = dimethylformamide) contains dinuclear {Mn II W V } - cyano-bridged anions, while the crystal structure of [Mn II (phen) 3 ] 2 [MnII(phen) 2 (μ-NC) 2 -W V (CN) 6 ] 2 (ClO 4 ) 2 ·9H 2 O (2) (phen = 1,10-phenanthroline) is built of tetranuclear {Mn II 2 W V 2} 2- square anions. Intramolecular Mn-W magnetic interactions through the cyano bridges are repr…
Active biomonitoring (moss-bags) of volcanic emissions on Mt. Etna
2011
Biomonitoring may be defined as the use of organisms and biomaterials (biomonitors) to obtain information on certain characteristics of a particular medium (atmosphere, hydrosphere etc.). In particular, mosses accumulate large amounts of trace metals, making them good bioaccumulators to estimate atmospheric pollution. The moss-bags technique, introduced in the early 1970’, has become very popular. Such active biomonitoring technique is particularly useful in highly polluted areas and has been extensively used in industrial and/or urban areas to examine deposition patterns and to recognize point sources of pollution. The main objective of this study, which represents the first application of…
The developmental dynamics of task-avoidant behavior and math performance in kindergarten and elementary school
2012
Besides cognitive factors, children's learning at school may be influenced by more dynamic phenomena, such as motivation and achievement-related task-avoidant behavior. The present study examined the developmental dynamics of task-avoidant behavior and math performance from kindergarten to Grade 4. A total of 225 children were tested for their arithmetic skills in kindergarten and in Grades 1, 2, and 4 of elementary school. Children's task-avoidant behavior in learning situations was rated by their teachers. The results of latent growth curve analyses showed that math performance and task-avoidant behavior develop in tandem: an increase in task-avoidant behavior was related to less improvem…
Drāmas elementu izmantošana jaunāko pusaudžu motivācijas veicināšanai angļu valodas gramatikas apgūšanā
2020
Šis diplomdarbs sniedz teorētisku pamatojumu un piedāvā praktiskus padomus drāmas tehnikas izmantošanai angļu valodas stundās pamatskolā. Uzsvars tika likts uz gramatikas kompetences attīstību. Pētījuma mērķis bija noskaidrot, vai ir iespējama drāmas elementu izmantošana pamatskolas angļu valodas stundās un noskaidrot vai tā attīsta izglītojamo gramatikas kompetenci. Prakses laikā tika veikta izpēte, izmantojot gadījuma pētījumu, kā galveno pētījumu metodi. Darbā tika izmantotas tādas datu vākšanas metodes kā novērojumi, anketas un gala testa analīze. Rezultāti pierādīja, ka drāmas paņēmienus var piemērot nodarbībām ar jaunākiem pusaudžiem, kuri studē angļu valodu, arī tika parādīts, ka tā …
Spēļošanas elementu izmantošana tālmācības vidusskolas skolēnu motivācijā
2020
Maģistra darbs “Spēļošanas elementu izmantošana tālmācības vidusskolas skolēnu motivācijā” ir izstrādāts ar mērķi izpētīt tos spēļošanas elementus, kuru izmantošana tālmācības izglītības procesā stimulētu izglītojamo motivāciju, balstoties uz teorētisko avotu un esošās situācijas izpēti. Maģistra darba aktualitāte ir saistīta ar pasaulē straujo izglītības vides digitalizāciju un mācību procesa papildināšanu ar dažādiem digitālajiem mācību līdzekļiem, mācību tehniskajiem līdzekļi, informācijas tehnoloģijām, mācīšanās platformām utml. Darbā raksturota tālmācība kā perspektīva un mūsdienīga izglītības ieguves forma, tālmācības mācīšanās process un mācīšanās īpatnības, spēļošanas elementu izman…
On time-harmonic Maxwell equations with nonhomogeneous conductivities : Solvability and FE-approximation
1989
The solvability of time-harmonic Maxwell equations in the 3D-case with nonhomogeneous conductivities is considered by adapting Sobolev space technique and variational formulation of the probJem in question. Moreover, a finite element approximation is presented in the 3D·case together with an error estimate in the energy norm. Some remarks are given to the 2D-problem arising from geophysics. peerReviewed
Evaluation of waterborne exposure to heavy metals in innate immune defences present on skin mucus of gilthead seabream (Sparus aurata)
2015
Aquatic animals are continuously exposed to chemical pollutants but the effects evoked in skin surfaces, which receive the most direct contact with them, are poorly investigated. Terminal carbohydrate composition and immunological components present in skin mucus of gilthead seabream (Sparus aurata L.) specimens exposed to waterborne sublethal dosages of heavy metals [arsenic (As2O3), cadmium (CdCl2) and mercury (CH3HgCl) at 5, 5 and 0.04 μM, respectively for 2, 10 and 30 days were analysed. Moreover, the presence of a fucose binding lectin (FBL) was evaluated by western blot and the protein profiles were by SDS-PAGE and HPLC. Results showed little effects of heavy metals in the presence of…
Durability of a 3D woven composite assisted by finite element multi-scale modelling
2012
International audience; The textile composite studied is a 3D woven composite. A unit cell is defined by using microscopic examinations of the microstructure. A multiscale approach assisted by the finite element method is performed in order to estimate the effective properties of the composite and then to access to local stress field. This approach allows the determination of the kind of load to which warp yarns are subjected. Moreover, detailed analysis of damaged model using different configurations of broken yarns are treated. The evolution of the stress concentration coefficient highlight the load transfers due to consecutive yarn breaks.
Indirect chronology method employing rare earth elements to identify Sagunto Castle mortar construction periods
2017
A novel indirect chronology method has been developed to identify Sagunto Castle construction periods. The method is based on the use of inductively coupled plasma mass spectrometry (ICP-MS) to determine rare earth elements (REE) and other trace elements in mortars. Additionally, a no destructive geochemical analysis based on X-ray fluorescence (XRF) was employed for major elements determination. Collected chemical data were processed through Principal Component Analysis (PCA) to highlight any differences among the mortars belonging to different buildings and construction periods. The results show that PCA analysis permits to discriminate construction periods according to mortar sample REE …
Search for Electron Antineutrino Appearance in a Long-baseline Muon Antineutrino Beam
2020
Electron antineutrino appearance is measured by the T2K experiment in an accelerator-produced antineutrino beam, using additional neutrino beam operation to constrain parameters of the Pontecorvo-Maki-Nakagawa-Sakata (PMNS) mixing matrix. T2K observes 15 candidate electron antineutrino events with a background expectation of 9.3 events. Including information from the kinematic distribution of observed events, the hypothesis of no electron antineutrino appearance is disfavored with a significance of 2.40 σ and no discrepancy between data and PMNS predictions is found. A complementary analysis that introduces an additional free parameter which allows non-PMNS values of electron neutrino and a…