5,177 research outputs found
Enhancement and suppression effects resulting from information structuring in sentences
Information structuring through the use of cleft sentences increases the processing efficiency of references to elements within the scope of focus. Furthermore, there is evidence that putting certain types of emphasis on individual words not only enhances their subsequent processing, but also protects these words from becoming suppressed in the wake of subsequent information, suggesting mechanisms of enhancement and suppression. In Experiment 1, we showed that clefted constructions facilitate the integration of subsequent sentences that make reference to elements within the scope of focus, and that they decrease the efficiency with reference to elements outside of the scope of focus. In Experiment 2, using an auditory text-change-detection paradigm, we showed that focus has similar effects on the strength of memory representations. These results add to the evidence for enhancement and suppression as mechanisms of sentence processing and clarify that the effects occur within sentences having a marked focus structure
Thermodynamic data for fifty reference elements
This report is a compilation of thermodynamic functions of 50 elements in their standard reference state. The functions are C(sub p)(sup 0), (H(sup 0)(T) - H(sup 0)(0)), S(sup 0)(T), and -(G(sup 0)(T) - H(sup 0)(O)) for the elements Ag, Al, Ar, B, Ba, Be, Br2, C, Ca, Cd, Cl2, Co, Cr, Cs, Cu, F2, Fe, Ge, H2, He, Hg, I2, K, Kr, Li, Mg, Mn, Mo, N2, Na, Nb, Ne, Ni, O2, P, Pb, Rb, S, Si, Sn, Sr, Ta, Th, Ti, U, V, W, Xe, Zn, and Zr. Deuterium D2 and electron gas e(sup -) are also included. The data are tabulated as functions of temperature as well as given in the form of least-squares coefficients for two functional forms for C(sub p)(sup 0) with integration constants for enthalpy and entropy. One functional form for C(sub p)(sup 0) is a fourth-order polynomial and the other has two additional terms, one with T(exp -1) and the other with T(exp -2). The gases Ar, D2, e(sup -), H2, He, Kr, N2, Ne, O2, and Xe are tabulated for temperatures from 100 to 20,000 K. The remaining gases Cl2 and F2 are tabulated from 100 to 6000 K and 1000 to 6000 K. The second functional form for C(sub p)(sup 0) has an additional interval from 6000 to 20,000 K for the gases tabulated to 20,000 K. The fits are constrained so that the match at the common temperature endpoints. The temperature ranges for the condensed species vary with range of the data, phase changes, and shapes of the C(sub p)(sup 0) curves
Laboratory and observational study of the interrelation of the carbonaceous component of interstellar dust and solar system materials
By studying the chemical and isotopic composition of interstellar ice and dust, one gains insight into the composition and chemical evolution of the solid bodies in the solar nebula and the nature of the material subsequently brought into the inner part of the solar system by comets and meteorites. It is now possible to spectroscopically probe the composition of interstellar ice and dust in the mid-infrared, the spectral range which is most diagnostic of fundamental molecular vibrations. We can compare these spectra of various astronomical objects (including the diffuse and dense interstellar medium, comets, and the icy outer planets and their satellites) with the spectra of analogs we produce in the laboratory under conditions which mimic those in these different objects. In this way one can determine the composition and abundances of the major constituents of the various ices and place general constraints on the types of organics coating the grains in the diffuse interstellar medium. In particular we have shown the ices in the dense clouds contain H2O, CH3OH, CO, perhaps some NH3 and H2CO, we well as nitriles and ketones or esters. Furthermore, by studying the photochemistry of these ice analogs in the laboratory, one gains insight into the chemistry which takes place in interstellar/precometary ices. Chemical and spectroscopic studies of photolyzed analogs (including deuterated species) are now underway. The results of some of these studies will be presented and implications for the evolution of the biogenic elements in interstellar dust and comets will be discussed
Assessment of the cross-protective capability of recombinant capsid proteins derived from pig, rat, and avian hepatitis E viruses (HEV) against challenge with a genotype 3 HEV in pigs
Hepatitis E virus (HEV), the causative agent of hepatitis E, is primarily transmitted via the fecal-oral route through contaminated water supplies, although many sporadic cases of hepatitis E are transmitted zoonotically via direct contact with infected animals or consumption of contaminated animal meats. Genotypes 3 and 4 HEV are zoonotic and infect humans and other animal species, whereas genotypes 1 and 2 HEV are restricted to humans. There exists a single serotype of HEV, although the cross-protective ability among the animal HEV strains is unknown. Thus, in this study we expressed and characterized N-terminal truncated ORF2 capsid antigens derived from swine, rat, and avian HEV strains and evaluated their cross-protective ability in a pig challenge model. Thirty, specific-pathogen-free, pigs were divided into 5 groups of 6 pigs each, and each group of pigs were vaccinated with 200 µg of swine HEV, rat HEV, or avian HEV ORF2 antigen or PBS buffer (2 groups) as positive and negative control groups. After a booster dose immunization at 2 weeks post-vaccination, the vaccinated animals all seroconverted to IgG anti-HEV. At 4 weeks post-vaccination, the animals were intravenously challenged with a genotype 3 mammalian HEV, and necropsied at 4 weeks post-challenge. Viremia, fecal virus shedding, and liver histological lesions were compared to assess the protective and cross-protective abilities of these antigens against HEV challenge in pigs. The results indicated that pigs vaccinated with truncated recombinant capsid antigens derived from three animal strains of HEV induced a strong IgG anti-HEV response in vaccinated pigs, but these antigens confer only partial cross-protection against a genotype 3 mammalian HEV. The results have important implications for the efficacy of current vaccines and for future vaccine development, especially against the novel zoonotic animal strains of HEV
What is the initiation step of the Grubbs-Hoveyda olefin metathesis catalyst?
Density function theory calculations reveal that the Grubbs-Hoveyda olefin metathesis pre-catalyst is activated by the formation of a complex in which the incoming alkene substrate and outgoing alkoxy ligand are both clearly associated with the ruthenium centre. The computed energies for reaction are in good agreement with the experimental values, reported here
Organic Synthesis via Irradiation and Warming of Ice Grains in the Solar Nebula
Complex organic compounds, including many important to life on Earth, are commonly found in meteoritic and cometary samples, though their origins remain a mystery. We examined whether such molecules could be produced within the solar nebula by tracking the dynamical evolution of ice grains in the nebula and recording the environments they were exposed to. We found that icy grains originating in the outer disk, where temperatures were less than 30 K, experienced UV irradiation exposures and thermal warming similar to that which has been shown to produce complex organics in laboratory experiments. These results imply that organic compounds are natural byproducts of protoplanetary disk evolution and should be important ingredients in the formation of all planetary systems, including our own
The 2.5-5.0 micron spectra of Io: Evidence for H2S and H2O frozen in SO2
The techniques of low temperature spectroscopy are applied to identify the constituents of the ices covering the surface of Io, a satellite of Jupiter. Infrared spectra of Io in the 4000-2000 cm exp -1 region, including new observational data, are analyzed using laboratory studies of plausible surface ices
A computational approach to implicit entities and events in text and discourse
In this paper we will focus on the notion of “implicit”
or lexically unexpressed linguistic elements that are
nonetheless necessary for a complete semantic interpretation
of a text. We refer to “entities” and “events” because
the recovery of the implicit material may affect all the modules
of a system for semantic processing, from the grammatically
guided components to the inferential and reasoning
ones. Reference to the system GETARUNS offers one possible
implementation of the algorithms and procedures needed
to cope with the problem and enables us to deal with all the
spectrum of phenomena. The paper will address at first the
following three types of “implicit” entities and events:
– the grammatical ones, as suggested by a linguistic theories
like LFG or similar generative theories;
– the semantic ones suggested in the FrameNet project, i.e.
CNI, DNI, INI;
– the pragmatic ones: here we will present a theory and an
implementation for the recovery of implicit entities and
events of (non-) standard implicatures.
In particular we will show how the use of commonsense
knowledge may fruitfully contribute to find relevant implied
meanings. Last Implicit Entity only touched on, though for
lack of space, is the Subject of Point of View, which is computed
by Semantic Informational Structure and contributes
the intended entity from whose point of view a given subjective
statement is expressed
Laboratory simulation of the photoprocessing and warm-up of cometary and pre-cometary ices: Production of complex organic molecules
The recent missions to Comet Halley detected large quantities of organic material on grains as well as organic molecules in the gas phase. A possible origin of these materials is the energetic processing of ice mantles on the grains prior to comet formation, either in the pre-solar nebula or the interstellar medium. This process was simulated in the laboratory by depositing interstellar ice analogs (H2O/CH3OH/CO/NH3) on a cold (10 K) substrate with simultaneous UV irradiation. The material evaporating during warm-up of the photolyzed ice as well as the residue remaining at room temperature was analyzed by a number of techniques. It was found that a large number of organic molecules of various complexity are synthesized during the simulation process, stressing the possible significance of UV photolysis for producing the organic Comet material
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