Схожість насіння та біометричні показники плодів павловнії повстис¬тої Paulownia Tomentosa Steud. різного географічного походження

Paulownia tomentosa Steud. – rapid growing wood breed, capable to regenerate many times by sprout shoots after the cutting of tree and accelerating the growth of subsequent generations, it is a perspective for plantation cultivation in Ukraine. The purpose of the work is to investigate the germination quality of the seeds of the Paulownia tomentosa and the biometric indicators of the fruits and seeds, depending on the geographical origin of the trees, to evaluate the possibility of using the zoned seeds for the cultivation of high quality planting material. Biometric indicators were determined on the basis of measurements of the size of the fruits obtained in different geographical regions of Ukraine (Lviv, Transcarpathian and Odessa oblasts). To determine the effect of temperature on crop quality, germination of seeds was carried out at two temperature regimes: +15…20 °С and +21…25 °С. To determine the effect of the duration of pre-wetting on similarity indicators, seeds were soaked in water with a temperature of +20 °С 24 and 48 hours. In the conditions of the Odessa region, Paulownia tomentosa forms larger fruits, the weight of which is dominated by a mass of fruits from the Transcarpathian and Lviv regions by 24 and 38 %. Seeds of this origin are heavier and are characterized by higher sprouting rates and the friendly appearance of seed germinations. In the temperature mode of sprouting + 20…25 °С, the technical germination of the Paulownia tomentosa seeds varies from 88 to 99 %, regardless of geographical origin. At pre-soaked seeds in water for 48 hours are increasing of germination by 4–5 %, when soaked for 24 hours – by 1–3 % compared to the control (without soaking). The energy of seed germination is increased by 10–40 % and by 8–27 %. In the seeds harvested in Odessa average of seed rest is the smallest and ranges from 6.4 to 7.3 days, which indicates a very high seed germination rate. The decrease in the temperature of germination of the Paulownia tomentosa seeds leads to a decrease in all similarity indicators. The technical germination of the seeds varies in the range of 66–79 %; compared with the germination at a temperature of + 20… 25 °С decreases in the studied index is 20–23 %. Preliminary soaking of seedlings at lower temperatures also has a positive effect on seed germination. Seeds of Paulownia tomentosa are characterized by a high technical germination, regardless of geographical origin. The temperature decreasing significantly slows the seed germination process and causes a decrease in germination indexes. The increase in the duration of the pre-wetting is due to an increase in the technical germination and energy of seed germination. In general, the studied seed of three origins is characterized by high crop qualities and can be used for growing seedling material.Наведено результати дослідження біометричних показників плодів та насіння Paulownia tomentosa Steud., заготовлених із дерев, що зростають у ґрунтово-кліматичних умовах Одеської, Закарпатської та Львівської областей. Встановлено, що в умовах Одеської області павловнія повстиста формує більші плоди. Насіння цього походження характеризується значною швидкістю проростання та дружністю появи сходів. Досліджено вплив змінного температурного режиму пророщування на посівні якості насіння різного географічного походження. Встановлено, що зниження температури пророщування спричиняє зменшення енергії проростання, лабораторної та абсолютної схожості насіння, збільшує середній насінний спокій. Оцінено вплив тривалості попереднього намочування на схожість насіння. Виявлено, що попереднє намочування насіння істотно підвищує показники схожості, його тривалість пов'язується з показниками енергії проростання, технічної та абсолютної схожості. Встановлено, що серед трьох походжень насіння найвища технічна схожість характерна для насіння з Львівської області. Насіння з Одеської області має найвищу енергію проростання. Загалом досліджуване насіння всіх трьох походжень характеризується високими посівними якостями, що свідчить про можливість використання районованого насіння для вирощування садивного матеріалу і створення насаджень з притаманною для материнських рослин біологічною стійкістю, зокрема до впливу низьких температур у конкретних ґрунтово-кліматичних умовах

Position observations of NEAs at the RTT150

In 2004-2007, 560 observations of 17 Near-Earth Asteroids of 15-21 magnitudes were made at the Russian-Turkish telescope (RTT150). The reduction was made using reference stars from the UCAC2 and USNO-B1 catalogues. The comparison of the observed and calculated positions of the asteroids using the HORIZONS system gave standard errors of a single position in the range 0.05÷H 0.50″. Analysis of the (O - C) is given in this paper. © 2008 American Institute of Physics

Synthesis and characterization of Dy3Fe5O12 nanoparticles fabricated with the anion resin exchange precipitation method

Dysprosium-iron garnet (DyIG) nanoparticles were synthesized with the new modification of the anion resin exchange precipitation method. Fourier transform infrared spectroscopy, X-ray diffraction, and transmission electron microscopy showed nanoparticles to be of the garnet structure with an excellent crystallinity. Magnetic properties were studied by using QUANTUM Design MPMS-XL system and the visible magnetic circular dichroism (MCD). Nanoparticles magnetic properties were close to those of bulk DyIG crystals. Dependence of the nanoparticles magnetization (M) on the external magnetic field (H) is described by a narrow hysteresis loop in relatively low fields and the strong linear M increase with the further H increase. The visible MCD of DyIG was studied in this work for the first time. The MCD spectra consisted of several peaks associated with electron transitions in iron and dysprosium ions located in different spectral intervals. Dependences of the MCD peak intensities on temperature and magnetic field were studied

Effects of processing parameters on the morphology, structure, and magnetic properties of Cu1−xFexCr2Se4 nanoparticles synthesized with chemical methods

Cu1−xFexCr2Se4 nanoparticles with x = 0, 0.2, and 0.4 were synthesized via thermal decomposition of metal nitrate or chloride salts and selenium powder using different precursor compositions and processing details. Single crystalline nano-belts or nano-rods coexist in the synthesized powder samples with hexagon-shaped plates in dependence on the precursor composition. The belts gathered into conglomerates forming “hierarchical” particles. Visible magnetic circular dichroism (MCD) of Cu1−xFexCr2Se4 nanoparticles embedded into a transparent matrix was investigated for the first time. The similarity of the MCD spectra of all samples showed the similarity of the nanoparticles electronic structure independent of their morphology. Basing on the MCD spectral maxima characteristics, electron transitions from the ground to the excited states were identified with the help of the conventional band theory and the multi-electron approach

Microstructure and magnetooptics of silicon oxide with implanted nickel nanoparticles

Metallic nickel nanoparticles of various sizes are formed in a thin near-surface layer in an amorphous SiO 2 matrix during 40-keV Ni + ion implantation at a dose of (0.25-1.0) × 10 17 ions/cm 2. The microstructure of the irradiated layer and the crystal structure, morphology, and sizes of nickel particles formed at various irradiation doses are studied by transmission electron microscopy and electron diffraction. The magnetooptical Faraday effect and the magnetic circular dichroism in an ensemble of nickel nanoparticles are studied in the optical range. The permittivity ε∧ tensor components are calculated for the implanted samples using an effective medium model with allowance for the results of magnetooptical measurements. The spectral dependences of the tensor ε∧ components are found to be strongly different from those of a continuous metallic nickel film. These differences are related to a disperse structure of the magnetic nickel phase and to a surface plasma resonance in the metal nanoparticles. © Pleiades Publishing, Inc., 2011

Prediction of the operating point of dendrites growing under coupled thermosolutal control at high growth velocity

We use a phase-field model for the growth of dendrites in dilute binary alloys under coupled thermosolutal control to explore the dependence of the dendrite tip velocity and radius of curvature upon undercooling, Lewis number (ratio of thermal to solutal diffusivity), alloy concentration, and equilibrium partition coefficient. Constructed in the quantitatively valid thin-interface limit, the model uses advanced numerical techniques such as mesh adaptivity, multigrid, and implicit time stepping to solve the nonisothermal alloy solidification problem for material parameters that are realistic for metals. From the velocity and curvature data we estimate the dendrite operating point parameter σ*. We find that σ* is nonconstant and, over a wide parameter space, displays first a local minimum followed by a local maximum as the undercooling is increased. This behavior is contrasted with a similar type of behavior to that predicted by simple marginal stability models to occur in the radius of curvature, on the assumption of constant σ*

Study of morphology, magnetic properties, and visible magnetic circular dichroism of Ni nanoparticles synthesized in SiO2 by ion implantation

A systematic study of ensembles of nickel nanoparticles fabricated by Ni+-ion implantation at a dose of (0.5-1.0)×1017 ions/cm2 in a thin near-surface layer of an amorphous SiO2 matrix by means of transmission electron microscopy (TEM), dc magnetic measurements, and magneto-optical technique is presented. TEM characterization of Ni nanoparticles proves the formation of isolated spherical nickel nanoparticles with diameters from 2 to 16 nm. The crystal structure and lattice constant of the nanoparticles correspond to face-centered-cubic Ni. The larger size nanoparticles are shown to have core-shell structure, which is unusual for the implantation conditions used. The shell of these nanoparticles consists of Ni, while the core has supposedly the composition coinciding with the matrix, i.e., SiO2. The core-shell nanoparticles in the investigated sample coexist with ordinary pure Ni nanoparticles, which strongly affects the magnetic and especially magneto-optic properties of the samples. For all three doses, the nanoparticles are in the superparamagnetic state at room temperature passing to the "frozen" state at lower temperatures. However, only the sample implanted with the lowest dose demonstrates the classic superparamagnetic behavior according to the shape of the experimental magnetization temperature dependencies for the zero-field-cooled (ZFC) and field-cooled regimes. This shape deviation from that characteristic of the pure superparamagnetic ensembles is ascribed mainly to the particle core-shell structure. The Ni nanoparticles' anisotropy constant estimated with the help of ZFC curves appears to exceed the bulk Ni anisotropy second constant approximately by two orders of magnitude. Magnetic circular dichroism (MCD) is characterized by spectral dependence modified strongly as compared to the MCD spectra of a continuous Ni film. In the spectral range 1.1-4.2 eV, the MCD spectrum consists of two broad maxima of opposite sign with the characteristics depending on the implantation dose and the measurement temperature. The MCD spectra analysis allows one to show that the higher-energy maximum (at 3.34-3.48 eV depending on the dose) is related to the surface plasmon resonance (SPR) excitation in pure Ni nanoparticles, while the lower-energy maximum (at 2.19-2.73 eV depending on the dose) should be associated with the SPR excitation in core-shell nanoparticles. © 2013 American Physical Society

The astrometric Gaia-FUN-SSO observation campaign of 99 942 Apophis

Astrometric observations performed by the Gaia Follow-Up Network for Solar System Objects (Gaia-FUN-SSO) play a key role in ensuring that moving objects first detected by ESA's Gaia mission remain recoverable after their discovery. An observation campaign on the potentially hazardous asteroid (99 942) Apophis was conducted during the asteroid's latest period of visibility, from 12/21/2012 to 5/2/2013, to test the coordination and evaluate the overall performance of the Gaia-FUN-SSO . The 2732 high quality astrometric observations acquired during the Gaia-FUN-SSO campaign were reduced with the Platform for Reduction of Astronomical Images Automatically (PRAIA), using the USNO CCD Astrograph Catalogue 4 (UCAC4) as a reference. The astrometric reduction process and the precision of the newly obtained measurements are discussed. We compare the residuals of astrometric observations that we obtained using this reduction process to data sets that were individually reduced by observers and accepted by the Minor Planet Center. We obtained 2103 previously unpublished astrometric positions and provide these to the scientific community. Using these data we show that our reduction of this astrometric campaign with a reliable stellar catalog substantially improves the quality of the astrometric results. We present evidence that the new data will help to reduce the orbit uncertainty of Apophis during its close approach in 2029. We show that uncertainties due to geolocations of observing stations, as well as rounding of astrometric data can introduce an unnecessary degradation in the quality of the resulting astrometric positions. Finally, we discuss the impact of our campaign reduction on the recovery process of newly discovered asteroids.Comment: Accepted for publication in A&