The phonological heritage of the scientists of the XX century: a linguistic and historiographical review

A great attention is paid to the linguistic-historiographic analysis of the works of the Moscow, Prague and Saint Petersburg phonological schools’ representatives, which were dedicated to the problem of the language phonemic syste

Photoabsorption in formaldehyde: Intensities and assignments in the discrete and continuous spectral intervals

Theoretical investigations of total and partial‐channel photoabsorption cross sections in molecular formaldehyde are reported employing the Stieltjes–Tchebycheff (S–T) technique and separated‐channel static‐exchange (IVO) calculations. Vertical one‐electron dipole spectra for the 2b_2(n), 1b_1(π), 5a_1(σ), 1b_2, and 4a_1 canonical molecular orbitals are obtained using Hartree–Fock frozen‐core functions and large basis sets of compact and diffuse normalizable Gaussians to describe the photoexcited and ejected electrons. The calculated discrete excitation spectra provide reliable zeroth‐order approximations to both valence and Rydberg transitions, and, in particular, the 2b_2(n) →nsa_1, npa_1, npb_2, and nda_2 IVO spectra are in excellent accord with recent experimental assignments and available intensity measurements. Convergent (S–T) photoionization cross sections in the static‐exchange (IVO) approximation are obtained for the 15 individual partial channels associated with ionization of the five occupied molecular orbitals considered. Resonance features in many of the individual‐channel photoionization cross sections are attributed to contributions from valencelike a_1σ^∗ (CO), a_1σ^∗ (CH), and b_2σ^∗ (CH)/π_y^∗ (CO) molecular orbitals that appear in the photoionization continua, rather than in the corresponding one‐electron discrete spectral intervals. The vertical electronic cross sections for ^1A_1→^1B_1, ^1B_2, and ^1A_1 excitations are in generally good accord with previously reported CI (S–T) predictions of continuum orbital assignments and intensities, although some discrepancies due to basis‐set differences are present in the ^1B_1 and ^1B_2 components, and larger discrepancies apparently due to channel coupling are present in the ^1A_1→^1A_1 cross section. Partial‐channel vertical electronic cross sections for the production of the five lowest parent‐ion electronic states are found to be in general agreement with the results of very recent synchrotron‐radiation photoelectron branching‐ratio measurements in the 20 to 30 eV excitation energy interval. Most important in this connection is the tentative verification of the predicted orderings in intensities of the partial‐ channel cross sections, providing support for the presence of a strong ka_1σ^∗ (CO) resonance in the (5a_1^(−1))^2A_1 channel. Finally, the total vertical electronic cross sections for absorption and ionization are in general accord with photoabsorption measurements, photoionization–mass–spectrometric studies, and the previously reported CI (S–T) calculations. Although further refined calculations including vibrational degrees of freedom and autoionization line shapes are required for a more precise quantitative comparison between theory and experiment, the present study should provide a reliable zeroth‐order account of discrete and continuum electronic dipole excitations in molecular formaldehyde

Photoexcitation and ionization in molecular fluorine: Stieltjes–Tchebycheff calculations in the static-exchange approximation

Theoretical investigation of outer (1pig, 1piu, 3sigmag) and inner (2sigmau, 2sigmag) valence-shell electronic photoexcitation and ionization cross sections in molecular fluorine are reported employing separated-channel static-exchange calculations and Stieltjes–Tchebycheff (S–T) moment-theory techniques. The discrete vertical electronic 1pig excitation series are found to be in good agreement with recent spectral assignments and previously reported theoretical studies, and those for 1piu, 3sigmag, 2sigmau and 2sigmag excitations are in general accord with position and intensity estimates based on quantum-defect analysis. Certain of the partial-channel photoionization cross sections in F2 are seen to exhibit resonancelike features similar to those reported recently in related S–T studies of photoionization in N2, CO, and O2. The resonances can be attributed to valencelike and pre-Rydberg diabatic states that cross the outer limbs of appropriate Rydberg series and corresponding ionic-state potential curves as functions of internuclear coordinate, giving rise to large continuum transition intensities at the ground-state equilibrium internuclear separation. In contrast to the situation in N2, CO, and O2, however, there is no evidence of a resonance like sigma-->sigma* feature in the 3sigmag-->ksigmau photoionization channel in F2. Rather, this resonance in F2 appears as a strong N-->Vg transition below the 3sigmag ionization threshold, and the corresponding partial-channel photoionization cross section is seen to be structureless. Although experimental studies of partial-channel photoionization cross sections are apparently unavailable for comparison, the calculations reported here should provide reliable approximations to the dipole excitation/ionization spectra in F2, and are helpful in understanding and clarifying the dependences of photoionization spectra in light diatomic molecules on shell occupancy and equilibrium internuclear separation when compared with the results of previous studies of photoionization in N2, CO, and O2

Scattering matrix approach to the dissociative recombination of HCO+ and N2H+

We present a theoretical study of the indirect dissociative recombination of linear polyatomic ions at low collisional energies. The approach is based on the computation of the scattering matrix just above the ionization threshold and enables the explicit determination of all diabatic electronic couplings responsible for dissociative recombination. In addition, we use the multi-channel quantum-defect theory to demonstrate the precision of the scattering matrix by reproducing accurately ab initio Rydberg state energies of the neutral molecule. We consider the molecular ions N2H+ and HCO+ as benchmark systems of astrophysical interest and improve former theoretical studies, which had repeatedly produced smaller cross sections than experimentally measured. Specifically, we demonstrate the crucial role of the previously overlooked stretching modes for linear polyatomic ions with large permanent dipole moment. The theoretical cross sections for both ions agree well with experimental data over a wide energy range. Finally, we consider the potential role of the HOC+ isomer in the experimental cross sections of HCO+ at energies below 10 meV

СТАН ТОНКОГО КИШЕЧНИКА У ЩУРІВ ІЗ ХРОНІЧНИМ ЕНТЕРОКОЛІТОМ НА ФОНІ СТРЕПТОЗОТОЦИНОВОГО ДІАБЕТУ: ПАТОБІОХІМІЧНІ ДАНІ

The purpose of our study was to establish the morphological changes of the small intestine wall of animals with diabetes mellitus, chronic enterocolitis and their combination, and to justify the mechanism of their development.Materials and methods. The study was conducted on 48 white non-linear male rats in accordance with the principles of the European Convention for the Protection of Laboratories. Diabetes mellitus was modeled by a single intraperitoneal administration of streptozotocin to animals aged 2 months, (Sigma Aldrich, USA, at a dose of 60 mg/kg of body weight). Chronic enterocolitis was induced by a free access of animals to 1.0% solution of carrageenan in drinking water for 1 month.Research results. In the histological examination of the small intestine walls of animals with diabetes were observed significant structural changes. It was noted shortening and flattening the villi of the mucous membrane, indicating their atrophy, while crypt elongation, their depth increased.There were marked manifestations of the inflammatory process in chronic enterocolitis in rats - widespread infiltration of the mucous membrane and submucosal layer by neutrophilic leukocytes with admixture of lymphocytes, histiocytes, eosinophils.Experimental animals with chronic enterocolitis on the background of diabetes suffered from a complex pathogenic effect of hyperglycemia and carrageenan, therefore, structural-functional changes of the small intestine were characterized by a large polymorphism.Conclusions. The analysis of the data gives possibility to conclude that in diabetes mellitus against hyperproduction of free oxygen radicals, structural changes in the small intestine wall of white rats are characterized by the prevalence of dystrophic processes, which can be considered like morphological reflection of enteropathy. In animals with chronic enterocolitis, high concentrations of the tumor necrosis factor determine the morphological picture of inflammation. In chronic enterocolitis combined with diabetes, there is a combination of signs of enteropathy and enteritis with the maximum values of the indicators of free oxygen radicals and tumor necrosis factor alpha and the degree of severity of pathological changes was higher than in the isolated models of these pathological states.Целью нашего исследования было установить морфологические изменения стенки тонкой кишки животных с сахарным диабетом, хроническим энтероколитом и их сочетанием и обосновать механизм их развития.Материалы и методы. Исследование проведено на 36 белых нелинейных самцах-крысах с соблюдением принципов Европейской конвенции по защите лабораторных животных. Сахарный диабет моделировали путем однократного внутрибрюшинного введения животным стрептозотоцина (Sigma Aldrich, США, в дозе 60 мг/кг массы тела). Хронический энтероколит был воссоздан путем свободного доступа животных к 1,0 % водному раствору каррагинана в течение 1 месяца.Результаты исследований. При гистологическом исследовании стенки тонкого кишечника животных с сахарным диабетом наблюдались существенные структурные изменения. Отмечалось укорочение и уплощение ворсинок слизистой оболочки, что свидетельствует об их атрофии, в то же время крипты удлинялись, глубина их увеличивалась.При хроническом энтероколите у крыс наблюдались выраженные проявления воспалительного процесса – распространенная инфильтрация слизистой оболочки и подслизистого слоя нейтрофильными лейкоцитами с примесью лимфоцитов, гистиоцитов, эозинофилов.Подопытные животные с хроническим энтероколитом на фоне сахарного диабета испытывали комплексное патогенное действие гипергликемии и каррагинана, поэтому структурно-функциональные изменения тонкой кишки у них характеризовались большим полиморфизмом.Выводы. Анализ приведенных выше данных позволяет сделать вывод, что при сахарном диабете на фоне гиперпродукции активных форм кислорода структурные изменения стенки тонкого кишечника белых крыс характеризуются преобладанием дистрофических процессов, которые можно считать морфологическим отражением энтеропатии. У животных с хроническим энтероколитом высокие концентрации фактора некроза опухолей-альфа обусловливают морфологическую картину воспаления. При хроническом энтероколите на фоне стретозотоцинового диабета наблюдается сочетание признаков энтеропатии и энтерита с максимальными значениями показателей активных форм кислорода и фактора некроза опухолей-альфа, при этом степень выраженности патологических изменений была выше, чем при изолированном моделировании указанных патологических состояний.Метою нашого дослідження було встановити морфологічні зміни стінки тонкої кишки тварин з цукровим діабетом, хронічним ентероколітом та їх поєднанням й обгрунтувати механізм їх розвитку.Матеріал і методи. Дослідження проведено на 36 білих нелінійних самцях-щурах з дотриманням принципів Європейської конвенції із захисту лабораторних тварин. Цукровий діабет моделювали шляхом однократного внутрішньоочеревинного введення тваринам стрептозотоцину (Sigma Aldrich, США, в дозі 60 мг/кг маси тіла). Хронічний ентероколіт був відтворений  шляхом вільного доступу тварин до 1,0 % розчину карагінану у питній воді протягом 1 місяця.Результати. При гістологічному дослідженні стінки тонкого кишечника тварин з цукровим діабетом спостерігалися істотні структурні зміни. Відмічалося вкорочення і сплощення ворсинок слизової оболонки, що свідчить про їх атрофію, в той же час крипти видовжувались, глибина їх збільшувалася.При хронічному ентероколіті у щурів спостерігали виражені прояви запального процесу – поширену інфільтрацію слизової оболонки та підслизового шару нейтрофільними лейкоцитами з домішками лімфоцитів, гістіоцитів, еозинофілів.Піддослідні тварини з хронічним ентероколітом на тлі цукрового діабету зазнавали комплексної патогенної дії гіперглікемії та карагінану, тому структурно-функціональні зміни тонкого кишечника у них характеризувалися більшим поліморфізмом.Висновки. Аналіз наведених вище даних дає підстави зробити висновок, що при цукровому діабеті на фоні гіперпродукції активних форм оксигену структурні зміни стінки тонкого кишечника білих щурів характеризуються превалюванням дистрофічних процесів, які можна вважати морфологічним відображенням ентеропатії. У тварин з хронічним ентероколітом високі концентрації фактора некрозу пухлин-альфа зумовлюють морфологічну картину запалення. При хронічному ентероколіті на фоні стрептозотоцинового діабету спостерігається поєднання ознак ентеропатії та ентериту з максимальними значеннями показників активних форм оксигену і фактора некрозу пухлин-альфа, при цьому ступінь вираженості патологічних змін був вищим, ніж при ізольованому моделюванні вказаних патологічних станів

Ab initio study of vibrational excitation of HF by low-energy electrons

Fixed-nuclei, static-exchange calculations have been performed to study the vibrational-rotational excitation of HF by electrons from threshold to 5 eV. Our calculated, R-dependent K-matrix elements in 2Σ+, 2Π, and 2Δ symmetry are combined with exact point-dipole and laboratory-frame first-Born-approximation results for higher symmetries to obtain converged, integrated cross sections. The calculations show strong threshold peaks which are related to the dependence of the 2Σ+ K-matrix elements on internuclear distance at small scattering energies

Observations of H3+ in the Diffuse Interstellar Medium

Surprisingly large column densities of H3+ have been detected using infrared absorption spectroscopy in seven diffuse cloud sightlines (Cygnus OB2 12, Cygnus OB2 5, HD 183143, HD 20041, WR 104, WR 118, and WR 121), demonstrating that H3+ is ubiquitous in the diffuse interstellar medium. Using the standard model of diffuse cloud chemistry, our H3+ column densities imply unreasonably long path lengths (~1 kpc) and low densities (~3 cm^-3). Complimentary millimeter-wave, infrared, and visible observations of related species suggest that the chemical model is incorrect and that the number density of H3+ must be increased by one to two orders of magnitude. Possible solutions include a reduced electron fraction, an enhanced rate of H2 ionization, and/or a smaller value of the H3+ dissociative recombination rate constant than implied by laboratory experiments.Comment: To be published in Astrophysical Journal, March 200

НЕИММУННЫЙ ОТЁК ПЛОДА ПРИ ВНУТРИУТРОБНОЙ ИНФЕКЦИИ

Nonimmune hydrops fetalis (NIHF) may be due to congenital infections. This article examines the congenital infections associated with NIHF – parvovirus and syphilis. Particular attention is paid to data verification infection and specificity of morphological changes in the placenta.Внутриутробная инфекция может сопровождаться неиммунным отёком плода. В данной статье приводятся практические наблюдения случаев неиммунного отёка плода при парвовирусной инфекции и сифилисе. Особое внимание уделено верификации данных инфекций и специфичности морфологических изменений в плаценте

Enhanced cosmic-ray flux toward zeta Persei inferred from laboratory study of H3+ - e- recombination rate

The H3+ molecular ion plays a fundamental role in interstellar chemistry, as it initiates a network of chemical reactions that produce many interstellar molecules. In dense clouds, the H3+ abundance is understood using a simple chemical model, from which observations of H3+ yield valuable estimates of cloud path length, density, and temperature. On the other hand, observations of diffuse clouds have suggested that H3+ is considerably more abundant than expected from the chemical models. However, diffuse cloud models have been hampered by the uncertain values of three key parameters: the rate of H3+ destruction by electrons, the electron fraction, and the cosmic-ray ionisation rate. Here we report a direct experimental measurement of the H3+ destruction rate under nearly interstellar conditions. We also report the observation of H3+ in a diffuse cloud (towards zeta Persei) where the electron fraction is already known. Taken together, these results allow us to derive the value of the third uncertain model parameter: we find that the cosmic-ray ionisation rate in this sightline is forty times faster than previously assumed. If such a high cosmic-ray flux is indeed ubiquitous in diffuse clouds, the discrepancy between chemical models and the previous observations of H3+ can be resolved.Comment: 6 pages, Nature, in pres