Search results for "shift"
showing 10 items of 1226 documents
The effect of some amines and alcohols on the organized structure of [bmim][BF4] investigated by 1H NMR spectroscopy
2008
The effect exerted by some amines and alcohols on the 1H NMR spectra of 1-butyl-3- methylimidazolium tetrafluoroborate [bmim][BF4] has been studied. This ionic liquid, which is one of the most widely used, is characterized by a high structural order degree, as a consequence of the symmetry and the coordination ability of the anion. In order to have information about the dependence of the detected effects on the alcohol or amine structure, some different primary, secondary and tertiary amines and alcohols have been considered. Furthermore, in the case of amines, their basicity has been also taken into account. Both amines and alcohols induce variation in chemical shifts values and signal mul…
A Language Shift Simulation Based on Cellular Automata
2011
Language extinction is a widespread social phenomenon affecting several million people throughout the world today. By the end of this century, more than 5100 of the approximately 6000 languages currently spoken around the world will have disappeared. This is mainly because of language shifts, i.e., because a community of speakers stops using their traditional language and speaks a new one in all communication settings. In this study, the authors present the properties of a cellular automaton that incorporates some assumptions from the Gaelic-Arvanitika model of language shifts and the findings on the dynamics of social impacts in the field of social psychology. To assess the cellular automa…
On the sensitivity of bridge seismic response with local soil amplification
1998
The paper presents a numerical sensitivity study of the local site effects on structural response. Following a recently developed model of spatial coherency and a concept of a simple site coefficient the local site effects are modelled as filtrations of excitation processes with a frequency shift. An analysis of a bridge response with supports founded on different soils is carried out. The joint effects of dynamic response and pseudostatic motion are considered. Two types of response are analysed: longitudinal and transverse. The differences between dynamic displacements and force responses are pointed out.
Preparation and nonlinear optics of monodisperse oligo(1,4-phenyleneethynylene)s
2001
Oligo(1,4-phenyleneethynylene)s 1a−e, with solubilizing propoxy side chains, were prepared by use of Hagihara−Sonogashira coupling reactions. The synthetic strategy was based on a building block system and on the use of trimethylsilyl and triisopropylsilyl protecting groups that could be cleaved selectively. The extension of the conjugation with an increasing number of repeat units provokes a bathochromic shift of the long wavelength absorption and a superlinear increase of the second hyperpolarizability |γ|. The corresponding third harmonic generation (THG) measurements were performed using polystyrene matrices and variable laser wavelengths. We conclude that the conjugation length is much…
Orthometalation of Tris(3-sodium sulfonatophenyl)phosphine with Dirhodium(II) Acetate
1998
Tetraacetatodirhodium(II) reacts with tris(3-sodium sulfonatophenyl)phosphine (TPPTS) giving [Rh2(μ-OOCCH3)3{μ-(3-NaO3SC6H3)P(C6H4SO3Na-3)2}(HOOCCH3)]·6H2O (1) and [Rh2(μ-OOCCH3)2{μ-(3-NaO3SC6H3)P(C6H4SO3Na-3)2}2(HOOCCH3)]·12H2O (2). Their structures and properties have been studied by electronic, IR, and 31P{1H}, 1H, 1H{31P}, and 13C{1H} NMR spectroscopies. In compound 1, one of the acetate bridges is replaced by a phosphine ligand, orthometalated via the C2 carbon atom of the phenyl ring. One axial site of the Rh24+ core is occupied by a sulfonato group of the metalated ring and another one by a labile molecule of acetic acid. 1H NMR spectroscopy shows that chemical shifts of the aromatic…
The influence of ENSO on winter rainfall in South Africa
2011
Whereas the impact of ENSO on the African summer rainfall regions is largely documented and still regularly investigated, little is known about its impact on the winter rainfall regions located at the southwestern and northwestern tips of Africa. Yet, these regions are densely inhabited and are net exporters of high-quality agricultural products. Here we analyze the relationship between El Nino Southern Oscillation (ENSO) and South Africa austral winter rainfall using a 682 raingauges daily rainfall database documenting the period 1950–1999. The May, June and July (MJJ) seasonal rainfall amount shows a positive correlation with the Nino3.4 index that becomes significant since the so-called …
Accumulation of sleep loss among shift-working truck drivers.
2021
Sleep loss is known to contribute to road traffic accidents. Professional drivers are vulnerable to curtailment of sleep due to long driving bouts and shift work. To fill in the gap in the literature related to the buildup of sleep loss in irregular shift systems, we recorded the sleep and working hours of 47 shift-working long-haul truck drivers during a two-week period. Sleep (time in bed) was verified by actigraphy and sleep logs. Sleepiness was measured using the Karolinska Sleepiness Scale (KSS). Individual sleep need was based on self-assessments. We examined the accumulated sleep versus self-reported sleep need across the study period, using midnights as points of observation, and th…
Predicting 19F NMR Chemical Shifts: A Combined Computational and Experimental Study of a Trypanosomal Oxidoreductase–Inhibitor Complex
2020
Abstract The absence of fluorine from most biomolecules renders it an excellent probe for NMR spectroscopy to monitor inhibitor–protein interactions. However, predicting the binding mode of a fluorinated ligand from a chemical shift (or vice versa) has been challenging due to the high electron density of the fluorine atom. Nonetheless, reliable 19F chemical‐shift predictions to deduce ligand‐binding modes hold great potential for in silico drug design. Herein, we present a systematic QM/MM study to predict the 19F NMR chemical shifts of a covalently bound fluorinated inhibitor to the essential oxidoreductase tryparedoxin (Tpx) from African trypanosomes, the causative agent of African sleepi…
Mākoņskaitļošanas pielietojums tīmekļa lietotņu izstrādē
2022
Arvien vairāk mūsdienās tīmekļa lietotņu izstrādē tiek pielietota mākoņskaitļošana. Mākoņskaitļošanas iespējas programmatūras izstrādātājiem piedāvā vairākas kompānijas. Izmantojot šīs iespējas, eksistē dažādas pieejas un platformas kā izstrādāt mākoņbāzētas lietotnes. Lai veiktu šādu lietotņu izstrādi, ir jāiegulda pētniecisks darbs, analizējot katru pakalpojuma sniedzēju atsevišķi. Maģistra darba mērķis ir apskatīt tīmekļa lietotņu izstrādes veidus, kas ir saderīgi ar mākoņskaitļošanu, mākoņskaitļošanas jēdzienu – pakalpojumu veidus un to pielietojumus, piederības modeļus, izpētīt dažādus mākoņu pakalpojumus un to sniedzējus, veikt lietotņu izvietošanu dažādās mākoņu platformās, aprakstot…
Old concepts, new ideas: approaches to translation shifts
2009
This paper traces the development of the translation shift concept from its origins in the linguistics-oriented era of translation studies to its current revival in computer-based approaches: after a presentation of the traditional approaches by John C. Catford, Jean-Paul Vinay and Jean Darbelnet, Eugene A. Nida, and Kitty van Leuven-Zwart, several recent studies that have integrated the concept of translation shifts are introduced and discussed. This comparison of old and new approaches reveals that the attitudes towards shifts have changed from mildly prescriptive to neutrally descriptive. The paper concludes with a general evaluation of the place of linguistic approaches in translation s…