Search results for "Citation"
showing 10 items of 1710 documents
Dominance and leadership in research activities: Collaboration between countries of differing human development is reflected through authorship order…
2017
Introduction Scientific collaboration is an important mechanism that enables the integration of the least developed countries into research activities. In the present study, we use the order of author signatures and addresses for correspondence in scientific publications as variables to analyze the interactions between countries of very high (VHHD), high (HHD), medium (MHD), and low human development (LHD). Methodology We identified all documents published between 2011 and 2015 in journals included in the Science Citation Index-Expanded categories’ of Tropical Medicine, Infectious Diseases, Parasitology, and Pediatrics. We then classified the countries participating in the publications acco…
Rigid versus Flexible Protein Matrix: Light-Harvesting Complex II Exhibits a Temperature-Dependent Phonon Spectral Density
2018
Dynamics-function correlations are usually inferred when molecular mobility and protein function are simultaneously impaired at characteristic temperatures or hydration levels. In this sense, excitation energy transfer in the photosynthetic light-harvesting complex II (LHC II) is an untypical example because it remains fully functional even at cryogenic temperatures relying mainly on interactions of electronic states with protein vibrations. Here, we study the vibrational and conformational protein dynamics of monomeric and trimeric LHC II from spinach using inelastic neutron scattering (INS) in the temperature range of 20-305 K. INS spectra of trimeric LHC II reveal a distinct vibrational …
Excitonic Energy Level Structure and Pigment−Protein Interactions in the Recombinant Water-Soluble Chlorophyll Protein. I. Difference Fluorescence Li…
2011
Difference fluorescence line-narrowing spectroscopy at 4.5 K was employed to investigate electron-phonon and electron-vibrational coupling strengths of the lower exciton level of water-soluble chlorophyll-binding protein (WSCP) from cauliflower reconstituted with chlorophyll a or chlorophyll b, respectively. The electron-phonon coupling is found to be moderate with integral Huang-Rhys factors S in the order of 0.81-0.85. A weak dependence of S on excitation wavelength within the inhomogeneously broadened fluorescence origin band is attributed to a sizable contribution of nonresonant excitation that varies with excitation wavelength. The strongly asymmetric and highly structured one-phonon p…
Optically Detected Magnetic Resonance of Chlorophyll Triplet States in Water-Soluble Chlorophyll Proteins from Lepidium virginicum: Evidence for Exci…
2018
Optically detected magnetic resonance of triplet states populated by photoexcitation in water-soluble chlorophyll proteins (WSCPs) from Lepidium virginicum has been performed using both absorption and fluorescence detection. Well resolved triplet-singlet (T-S) spectra have been obtained and interpreted in terms of electronic interactions among the four chlorophylls (Chls), forming two dimers in the WSCP tetramer. Localization of the triplet state on a single Chl leads to a redistribution of the oscillator strength in the remaining three Chls of the complex. By comparing the spectra with those obtained on a substoichiometric WSCP complex containing only 2 Chls per protein tetramer, we proved…
Effect of annealing temperature on persistent luminescence of Y3Al2Ga3O12:Cr3+ co-doped with Ce3+ and Pr3+
2021
Abstract Y3(Al,Ga)5O12 (YAGG) materials doped with Ce3+, Cr3+ and Pr3+ were synthesized by using a modified Pechini method and subsequently annealed in air at selected temperatures between 900 and 1500 °C. According to X-ray powder diffraction (XRPD) and transmission electron microscopy (TEM) analyses, the particles and size distributions become large and broad, respectively, due to sintering and agglomeration at high annealing temperatures. Based on infrared (FTIR) spectra and calculation of multi-phonon de-excitation probabilities, the high energy O–H vibrations are not causing significant multi-phonon de-excitation of the emitting 5d level of Ce3+ if the annealing temperature is above 90…
Circular dichroism of magnetically induced transitions for D 2 lines of alkali atoms
2018
In this letter we study magnetic circular dichroism in alkali atoms exhibiting asymmetric behaviour of magnetically induced transitions. The magnetic field induces transitions between hyperfine levels of alkali atoms and in the range of magnetic field, the intensities of these transitions experience significant enhancement. We have inferred a general rule applicable for the D 2 lines of all alkali atoms, that is the transition intensity enhancement is around four times larger for the case of than for excitation for , whereas it is several hundreds of thousand times larger in the case of than that for polarization for . This asymmetric behaviour results in circular dichroism. For experimenta…
Magnetic Circular Dichroism in Two-Photon Photoemission
2009
We report the observation of magnetic circular dichroism (MCD) in two-photon photoemission (2PPE). The Heusler alloys Ni2MnGa and Co2FeSi were investigated by excitation with femtosecond laser light, showing MCD asymmetries of A=(3.5+/-0.5)x10;{-3} for Ni2MnGa and of A=(2.1+/-1.0)x10;{-3} for Co2FeSi, respectively. A theoretical explanation is provided based on local spin-density calculations for the magnetic dichroic response; the computed 2PPE MCD agrees well with the experiment. The observed 2PPE magnetic contrast represents an interesting alternative for future time-resolved photoemission studies on surface magnetism practicable in the laboratory.
Investigations of Chl a aggregates cross-linked by dioxane in 3-methylpentane
1997
In this work, dioxane-bound aggregates of chlorophyll a are prepared in 3-methylpentane. The properties of the aggregates are studied by using steady-state and time-resolved spectroscopies. The Q -region absorption spectrum of the y chlorophyll a-dioxane aggregate shows four clearly resolvable narrow bands with comparable intensities. The band maxima are located at 683, 689, 698 and 702 nm. The emission spectrum consists of two emission bands centred at 699 and 702 nm suggesting the presence of two types of aggregates. High degree of fluorescence polarization is detected yielding the angles between the absorption transition moments with respect to the 702 nm emission transition moment. The …
Effects of seniority, gender and geography on the bibliometric output and collaboration networks of European Research Council (ERC) grant recipients.
2019
Assessing the success and performance of researchers is a difficult task, as their grant output is influenced by a series of factors, including seniority, gender and geographical location of their host institution. In order to assess the effects of these factors, we analysed the publication and citation outputs, using Scopus and Web of Science, and the collaboration networks of European Research Council (ERC) starting (junior) and advanced (senior) grantees. For this study, we used a cohort of 355 grantees from the Life Sciences domain of years 2007-09. While senior grantees had overall greater publication output, junior grantees had a significantly greater pre-post grant award increase in …
An output-only stochastic parametric approach for the identification of linear and nonlinear structures under random base excitations: Advances and c…
2014
In this paper a time domain output-only Dynamic Identification approach for Civil Structures (DICS) first formulated some years ago is reviewed and presented in a more generalized form. The approach in question, suitable for multi- and single-degrees-of-freedom systems, is based on the statistical moments and on the correlation functions of the response to base random excitations. The solving equations are obtained by applying the Itô differential stochastic calculus to some functions of the response. In the previous version ([21] Cavaleri, 2006; [22] Benfratello et al., 2009), the DICS method was based on the use of two classes of models (Restricted Potential Models and Linear Mass Proport…