1,729 research outputs found
The logic and linguistic model for automatic extraction of collocation similarity
The article discusses the process of automatic identification of collocation similarity. The semantic analysis is one of the most advanced as well as the most difficult NLP task. The main problem of semantic processing is the determination of polysemy and synonymy of linguistic units. In addition, the task becomes complicated in case of word collocations. The paper suggests a logical and linguistic model for automatic determining semantic similarity between colocations in Ukraine and English languages. The proposed model formalizes semantic equivalence of collocations by means of semantic and grammatical characteristics of collocates. The basic idea of this approach is that morphological, syntactic and semantic characteristics of lexical units are to be taken into account for the identification of collocation similarity. Basic mathematical means of our model are logical-algebraic equations of the finite predicates algebra. Verb-noun and noun-adjective collocations in Ukrainian and English languages consist of words belonged to main parts of speech. These collocations are examined in the model. The model allows extracting semantically equivalent collocations from semi-structured and non-structured texts. Implementations of the model will allow to automatically recognize semantically equivalent collocations. Usage of the model allows increasing the effectiveness of natural language processing tasks such as information extraction, ontology generation, sentiment analysis and some others
Crystallization and preliminary X-ray studies of snake gourd lectin: homology with type II ribosome-inactivating proteins
Efficient microwave synthesis of novel aromatic esters catalyzed by zirconia and its modified forms: a kinetic study
A series of solid acids such as ZrO2, 5% Mo(VI)/ZrO2, 10% Mo(VI)/ZrO2, 20% Mo(VI)/ZrO2 and SO42-/ZrO2 were prepared. These solid acids were characterized by BET, NH3-TPD/n-butylamine back titration, powder-XRD, FT-IR spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM) and ICP-OES techniques. The catalytic performance of these solid acids was evaluated in the synthesis of novel aromatic esters by the assistance of microwave irradiation and the catalytic activity of these solid acids was compared with pTsOH. The results clearly indicated that the zirconia based solid acids are efficient green catalysts for esterification reactions, which gave a maximum yield of the ester in a shorter reaction time and comparable catalytic activity of the pTsOH Bronsted acid. Kinetic studies were carried out to calculate the temperature coefficients (1.66 and 1.56) and energy of activation (66.82 kJ mol(-1) and 58.93 kJ mol(-1)) for SO42-/ZrO2 and pTsOH respectively. Pre-adsorption studies revealed that the reaction follows the Langmuir-Hinshelwood mechanism. The SO42-/ZrO2 solid acid catalyst was found to be reactivable and reusable
Non-linear characteristics in two-dimensional superconductors: Berezinskii-Kosterlitz-Thouless physics vs inhomogeneity
One of the hallmarks of the Berezinskii-Kosterlitz-Thouless (BKT) transition
in two-dimensional (2D) superconductors is the universal jump of the superfluid
density, that can be indirectly probed via the non-linear exponent of the
current-voltage characteristics. Here, we compare the experimental
measurements of characteristics in two cases, namely NbN thin films and
SrTiO-based interfaces. While the former display a paradigmatic example of
BKT-like non-linear effects, the latter do not seem to justify a BKT analysis.
Rather, the observed characteristics can be well reproduced theoretically
by modelling the effect of mesoscopic inhomogeneity of the superconducting
state. Our results offer an alternative perspective on the spontaneous
fragmentation of the superconducting background in confined 2D systems.Comment: Final version, as publishe
Surgical Stabilization of Femur Fractures in Post-Traumatic Hypoxemic Patients: When and Why?
Background: Post-traumatic hypoxemia can deteriorate during operative manipulations.
Objectives: In the present study, criteria-based approach was applied to determine optimum conditions for femur surgery. The aim of this study was to optimize perioperative management of post-traumatic hypoxemia.
Patients and Methods: In this prospective observational study, post-traumatic adults with PaO2 200 mmHg (FiO2 < 0.5, PEEP < 8 cm H2O).
Results: A total of 31 adults (26 males and 5 females) with LIS of 0.1 to 2.5 (26 patients) and > 2.5 (five patients) at admission were recruited. Sixteen patients were admitted within 24 hours and 15 between 24 and 90 hours after injury. Thirteen patients were operated within 24 hours. Post-operative LIS was improved. No adverse sequels or mortality were seen.
Conclusions: Appropriate surgical stabilization can be safely performed during established post-traumatic hypoxemia using a multidisciplinary approach, continuous monitoring, and serial investigations to diagnose fulminant pathology and associated injuries
Probability distribution of persistent spins in a Ising chain
We study the probability distribution of , the fraction of
spins unflipped till time , in a Ising chain with ferromagnetic
interactions. The distribution shows a peak at and in general is
non-Gaussian and asymmetric in nature. However for it shows a
Gaussian decay. A data collapse can be obtained when versus
is plotted with and .
Interestingly, shows a different behaviour compared to , the persistence probability which follows the well-known behaviour
. A quantitative estimate of the asymmetry and
non-Gaussian nature of is made by calculating its skewness and
kurtosis.Comment: 4 pages, submitted to J. Phys
Three Spin Spiky Strings in beta-deformed Background
We study rigidly rotating strings in -deformed
background with one spin along AdS and two angular momenta along . We
find the spiky string solutions and present the dispersion relation among
various charges in this background. We further generalize the result to the
case of four angular momenta along .Comment: 12 pages, minor corrections, added references, to appear in JHE
CH radio emission from heiles cloud 2 as a tracer of molecular cloud evolution
A mapping observation of the -type doubling transition (3.3
GHz) of CH has been conducted toward Heiles Cloud 2 (HCL2) in the Taurus
molecular cloud complex to reveal its molecular cloud-scale distribution. The
observations were carried out with the Effelsberg 100 m telescope. The CH
emission is found to be extended over the whole region of HCL2. It is brighter
in the southeastern part, which encloses the TMC-1 cyanopolyyne peak than in
the northwestern part. Its distribution extends continuously from the peak of
the neutral carbon emission (CI peak) to the TMC-1 ridge, as if it were
connecting the distributions of the [C I] and CO emissions. Since CH is
an intermediate in gas-phase chemical reactions from C to CO, its emission
should trace the transition region. The above distribution of the CH emission
is consistent with this chemical behavior. Since the CH abundance is subject to
the chemical evolutionary effect, the CH column density in HCL2 no longer
follows a linear correlation wit the H column density reported for diffuse
and translucent clouds. More importantly, the CH line profile is found to be
composed of the narrow and broad components. Although the broad component is
dominant around the CI peak, the narrow component appears in the TMC-1 ridge
and dense core regions such as L1527 and TMC-1A. This trend seems to reflect a
narrowing of the line width during the formation of dense cores. These results
suggest that the 3.3 GHz CH line is a useful tool for tracing the chemical and
physical evolution of molecular clouds.Comment: 8 page
A photoionization model of the compact HII region G29.96-0.02
We present a detailed photoionization model of G29.96-0.02 (hereafter
G29.96), one of the brightest Galactic Ultra Compact HII (UCHII) regions in the
Galaxy. This source has been observed extensively at radio and infrared
wavelengths. The most recent data include a complete ISO (SWS and LWS)
spectrum, which displays a remarkable richness in atomic fine-structure lines.
The number of observables is twice as much as the number available in previous
studies. In addition, most atomic species are now observed in two ionization
stages. The radio and infrared data on G29.96 are best reproduced using a
nebular model with two density components: a diffuse (n_e~680cm-3) extended (~1
pc) component surrounding a compact (~0.1 pc) dense (n_e~57000cm-3) core. The
properties of the ionizing star were derived using state-of-the-art stellar
atmosphere models. CoStar models yield an effective temperature of
\~30^{+2}_{-1} kK whereas more recent non-LTE line blanketed atmospheres with
stellar winds indicate somewhat higher values, Teff~32--38 kK. This range in
Teff is compatible with all observational constraints, including near-infrared
photometry and bolometric luminosity. The range 33-36 kK is also compatible
with the spectral type O5-O8 determined by Watson and Hanson (97) when recent
downward revisions of the effective temperature scale of O stars are taken into
account. The age of the ionizing star of G29.96 is found to be a few 10^6 yr,
much older than the expected lifetime of UCHII regions. Accurate gas phase
abundances are derived with the most robust results being Ne/S=7.5 and N/O=0.43
(1.3 and 3.5 times the solar values, respectively).Comment: Accepted in Astronomy and Astrophysic
Higher order antibunching is not a rare phenomenon
Since the introduction of higher order nonclassical effects, higher order
squeezing has been reported in a number of different physical systems but
higher order antibunching is predicted only in three particular cases. In the
present work, we have shown that the higher order antibunching is not a rare
phenomenon rather it can be seen in many simple optical processes. To establish
our claim, we have shown it in six wave mixing process, four wave mixing
process and in second harmonic generation process.Comment: 6 pages, no figure, Latex 2
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