Search results for "Moi"
showing 10 items of 2109 documents
Dielectric behaviour of a γ-irradiated polycarbonate
1980
Dielectric measurements on a γ-irradiated polycarbonate in a dose range 0–20 Mrad and at test frequencies of 103 and 104 Hz have been carried out. The glass transition temperature shows a maximum at 3.5 Mrad and then decreases at larger doses. This result is in line with other experiments (intrinsic viscosity, dynamic-mechanical measurements, etc) already reported: the Tg values are however larger in the present results. This is probably due to the plasticizing action of the absorbed moisture present in the previous tests. A Tg vs 1/[n]2 plot (1/[n]2 is proportional to 1/m ) allows to find the value of the glass transition point at an infinite molecular weight and the dependency of Tg on mo…
Maintaining information in Short-Term Memory between 2 and 6 years old of age : temporal forgetting and helping in maintaining the goal
2014
Working memory is an essential component of thought that is highly involved in learning and academic achievement. However, it is rarely studied in preschoolers, mainly because of a lack of suitable paradigms. Therefore, this thesis investigated the functioning of working memory in children between 2 and 6 years. For this purpose, two original paradigms were used. They were designed to be close to game situations which should help young children to focus their attention on the task. Firstly it was shown that the recall performance decreased over time, even in the absence of an interfering task. Children of this age therefore use a passive maintenance, i.e. without spontaneously implementing …
ChemInform Abstract: 3,4-Dihydro-2H-pyrrole-2-carbonitriles: Useful Intermediates in the Synthesis of Fused Pyrroles and 2,2′-Bipyrroles.
2016
Various heterocyclic structures containing the pyrrole moiety have been synthesized from easily accessible 3,4-dihydro-2H-pyrrole-2-carbonitriles in one-pot procedures. 5,6,7,8-Tetrahydroindolizines, 2,3-dihydro-1H-pyrrolizines as well as 6,7,8,9-tetrahydro-5H-pyrrolo[1,2-a]azepines were obtained from these precursors in high yields in an alkylation/annulation sequence. The same conditions were applied in the synthesis of a 5,8-dihydroindolizine, which could easily be transformed to the corresponding indolizine by dehydrogenation. Furthermore, oxidative couplings of 3,4-dihydro-2H-pyrrole-2-carbonitriles with copper(II)-salts furnished 2,2′-bipyrroles as well as 5,5′-bis(5-cyano-1-pyrroline…
Efficient Synthesis of 5-Chalcogenyl-1,3-oxazin-2-ones by Chalcogen-Mediated Yne-Carbamate Cyclisation: An Experimental and Theoretical Study
2014
A very efficient synthesis of 5-chalcogenyl-1,3-oxazin-2-ones has been accomplished by the chalcogen-mediated yne–carbamate cyclisation of chiral, non-racemic N-Cbz-protected propargylic amines using PhXY (X = Se, S, Te; Y = Br or Cl) as electrophile sources. The reactions gave good-to-excellent yields for a wide range of substrates. In all cases the reaction was totally regioselective, occurring by a 6-endo-dig process regardless of the nature of the reagent and of the substituents in the starting material. This methodology permits the formation of the 1,3-oxazin-2-one moiety as well as the simultaneous installation of a chalcogen functionality onto the heterocyclic ring. The experimental …
Reaction mechanism of regioisomerization in binuclear (diaminocarbene)PdII complexes
2021
Abstract A series of binuclear PdII carbene complexes were synthesized via the treatment of cis-[PdCl2(CNXyl)2] (1) with benzo-1,3-thiazol-2-amines (2–6) and structurally characterized. In every case the reaction leads to the mixture of two regioisomers, which are able to interconvert. The study of the regioisomerization of the binuclear diaminocarbene species showed that it is a first-order reaction, that is, it occurs intramolecularly, and was analyzed with the Hammett function. Electron-withdrawing substituents in the benzothiazole moiety of the complexes as well as increasing the solvent polarity accelerate the reaction. The solvent donor strength correlates less well with the isomeriza…
Structure alteration of a sandy-clay soil by biochar amendments
2014
The aim of the present study was to investigate structure alterations of a sandy-clay soil upon addition of different amounts of biochar (f bc ). All the f bc samples were analyzed by high energy moisture characteristic (HEMC) technique and 1H nuclear magnetic resonance (NMR) relaxometry. HEMC was applied in order to evaluate aggregate stability of biochar-amended soil samples. 1H NMR relaxometry experiments were conducted for the evaluation of the pore distributions through the investigation of water dynamics of the same samples. The HEMC technique revealed improvement in aggregate stability through measurements of the amount of drainable pores and the stability ratio. The latter increased…
Remote sensing data for crop yield in CONUS
2023
I) SUMMARY This database contains harmonized time series for the study of crop yields using remote sensing data and meteorological data. We collected information on soybean, corn, and wheat yields (t/ha) over the CONUS (continuous US) from USDA-NASS for years 2015–2018 at a county level, and collocated time series for the following variables: Enhanced Vegetation Index (EVI) from MODIS satellite (MOD13C1 v6 product) Soil Moisture (SM) from SMAP satellite through MT-DCA algorithm Vegetation Optical Depth (VOD) from SMAP satellite through MT-DCA algorithm Maximum temperature (TMAX) from Daymet v3 Precipitation (PRCP) from Daymet v3 II) CONTACT For questions, please email Laura Mart&iacut…
Laparoscopic Treatment of Endoscopic Sigmoid Colon Perforation
2006
Perforation of the colon after colonoscopy is a rare but potentially lethal complication. It usually occurs when endoscopy is performed for therapeutic purposes. In these cases the election of the best treatment is difficult and still controversial. Laparoscopy is a new approach for diagnosis and treatment of this condition. We report a case of a patient who was initially treated laparoscopically after a colonoscopic perforation. A postoperative leak was detected and the patient underwent open surgery. Possible therapeutic approaches and a literature review are discussed.
Vanhemman alkoholin tai huumeiden käyttö lastensuojelun palvelutarpeen arvioinnin taustalla : minkälaisena lastensuojelun palvelutarpeen arvioinnin p…
2017
Tutkimuksen tehtävänä on selvittää, kuinka sosiaalityöntekijät perustelevat lastensuojelun palvelutarpeen arvioinnin prosessin aikana tekemiään päätöksiä, kun lastensuojeluilmoitus on tehty vanhemman päihteidenkäytön vuoksi. Päihteidenkäytön vaikutusta lapsiin ja perheisiin on tutkittu laajasti ja päihteiden käytön negatiivisista vaikutuksista perheiden hyvinvointiin on kiistattomat tulokset. Omien työkokemusten perusteella heräsi kiinnostus tutkia lastensuojelun puuttumisen kynnystä ja sitä suhtautuvatko sosiaalityöntekijät eri tavalla alkoholin käyttäjiin ja huumeiden käyttäjiin. Tarkoituksena on tarkastella sosiaalityöntekijöiden päätöksentekoa ja sitä minkälaisena lastensuojelun palvelu…
A modified moiré technique for three-dimensional surface topography
2002
In this paper we present an optical technique based on the shadow moire method which allows the measurement and digitization of three-dimensional surfaces. The technique was tested through experimental work and the results were compared with those obtained by a coordinate measuring machine. Moving from the conventional shadow moire method, new features were implemented enabling us to overcome the main shortcomings of the conventional moire method. These include the need to assign the fringe order, the incapability of discerning concavity or convexity, the poor resolution and the complexity in the signal processing. All these problems have been solved by adding an element to generate a carri…