Models of infrared spectra of Sakurai's Object (V4334 Sgr) in 1997

Theoretical spectral energy distributions computed for a grid of hydrogen-deficient and carbon-rich model atmospheres have been compared with the observed infrared (1--2.5 $\mu$m) spectra of V4334 Sgr (Sakurai's Object) on 1997 April 21 and July 13. The comparison yields an effective temperature of \Tef = 5500 $\pm$ 200 K for the April date and \Tef = 5250 $\pm$ 200 K for July. The observed spectra are well fitted by Asplund et al. (1999) abundances, except that the carbon abundance is higher by 0.3 dex. Hot dust produces significant excess continuum at the long wavelength ends of the 1997 spectra. \keywords{Stars: individual: V4334 Sgr (Sakurai's Object) -- Stars: AGB and post-AGB evolution -- Stars: model atmospheres -- Stars: energy distributions -- Stars: effective temperatures}Comment: 6 pages, 7 eps figs, accepted for A

Emerging magnetism and electronic phase separation at titanate interfaces

The emergence of magnetism in otherwise nonmagnetic compounds and its underlying mechanisms have become the subject of intense research. Here we demonstrate that the nonmagnetic oxygen vacancies are responsible for an unconventional magnetic state common for titanate interfaces and surfaces. Using an effective multiorbital modelling, we find that the presence of localized vacancies leads to an interplay of ferromagnetic order in the itinerant t2g band and complex magnetic oscillations in the orbitally-reconstructed eg-band, which can be tuned by gate fields at oxide interfaces. The magnetic phase diagram includes highly fragmented regions of stable and phase-separated magnetic states forming beyond nonzero critical defect concentrations.Comment: 5 pages, 4 figure

Сутність зеленого маркетингу

В останні роки глобальне середовище погіршилося через поступове зростання населення. Знищення екологічних систем пов'язане зі способом життя та поведінкою споживачів, а саме з надмірним споживанням та нераціональним використанням ресурсів. До найважливіших глобальних екологічних проблем можна віднести зміни клімату, утрату біорізноманіття, забруднення атмосфери, утилізацію відходів. Сьогоднішній стан навколишнього середовища та катастрофічні наслідки життєдіяльності людства вимагають перегляду існуючих підходів до господарювання. Новий підхід має базуватись на глибокій повазі до довкілля, раціональному використанні ресурсів та переробці відходів виробництва і споживання. Однією з таких концепцій є зелений маркетинг. У статті дістало подальшого розвитку визначення екологічного маркетингу, що на відміну від існуючих, акцентує увагу на належності екологічного маркетингу до соціально-етичного маркетингу та узгодженні економічних та екологічних інтересів споживача, виробника та суспільства, шляхом формування та задоволення попиту на екологічну (екофрендлі, нешкідливу для довкілля) продукцію. Обґрунтовано відмінності зеленого маркетингу та традиційного. Основними відмінностями зеленого маркетингу є фокусування на довгострокових наслідках; першочергове зосередження на проблемах довкілля; маркетингове супровдження всього ланцюжка вартості товару від видобутку сировини до споживання і утилізації; застосування проактивної стратегії поводження з відходами. Виявлено основні переваги та проблеми використання зеленого маркетингу на підприємстві. Розширено поняття «зеленого» комплексу маркетингу шляхом додавання ще двох елементів: «Люди» та «Процеси». Зелений маркетинг заохочує покращення екологічної обізнаності клієнтів та надання їм можливості брати участь у природоохоронній діяльності, допомагає раціоналізувати використання обмежених ресурсів. Зелений маркетинг сприяє виробництву та розповсюдженню екологічно чистих товарів та послуг, що максимально задовольняє потреби споживачів найбільш екологічно чистим способом. Це сприяє зменшенню виснаження та експлуатації природних ресурсів.In recent years the global environment has deteriorated due to gradual growth of the population. The destruction of environmental systems is linked to the lifestyle and behavior of consumers, especially with excessive consumption and inappropriate use of resources. Climate change, loss of biodiversity, atmospheric pollution, and waste management are the most important global environmental issues. Today's state of the environment and the catastrophic consequences of human activities require revision of existing approaches to management. The new approach should be based on deep respect for the environment, rational use of resources and the recycling of waste from production and consumption. Green marketing addresses these challenges. The article further developed the definition of environmental marketing, which, unlike existing ones, emphasizes the importance of environmental marketing to social and ethical marketing and the harmonization of the economic and environmental interests of the consumer, producer and society by creating and satisfying the demand for environmental (eco-friendly, non-hazardous for environment) products. The difference between green marketing and traditional one is substantiated. The main difference in green marketing is focusing on its long-term effects; it gives priority focus on environmental issues; marketing support of the entire value chain of goods from extraction of raw materials to consumption and utilization; the use of a proactive waste management strategy. The main advantages and problems of using green marketing in the enterprise are discussed. The concept of a "green" marketing mix is expanded by adding two more elements: "People" and "Processes". Green marketing encourages customer training to improve their environmental awareness and enable them to participate in environmental activities, and helps to rationalize using of scarce resources. Green marketing contributes to the production and distribution of environmentally friendly goods and services that maximally meet the needs and desires of people in the most beneficial and environmentally friendly way. This contributes to reducing the depletion and exploitation of natural resources

Pre-hospital management of stroke

Scientific supervisor: I. Terletsk

Magnetically ordered state at correlated oxide interfaces: the role of random oxygen defects

Using an effective one-band Hubbard model with disorder, we consider magnetic states of the correlated oxide interfaces, where effective hole self-doping and a magnetially ordered state emerge due to electronic and ionic reconstructions. By employing the coherent potential approximation, we analyze the effect of random oxygen vacancies on the two-dimensional magnetism. We find that the random vacancies enhance the ferromagnetically ordered state and stabilize a robust magnetization above a critical vacancy concentration of about c=0.1. In the strong-correlated regime, we also obtain a nonmonotonic increase of the magnetization upon an increase of vacancy concentration and a substantial increase of the magnetic moments, which can be realized at oxygen reduced high-Tc cuprate interfaces.Comment: 8 pages, 2 figures, submitted to J Supercond Novel Magnetism (ICSM12 conference contribution

Magnetism and superconductivity at LAO/STO-interfaces: the role of Ti 3d interface electrons

Ferromagnetism and superconductivity are in most cases adverse. However, recent experiments reveal that they coexist at interfaces of LaAlO3 and SrTiO3. We analyze the magnetic state within density functional theory and provide evidence that magnetism is not an intrinsic property of the two-dimensional electron liquid at the interface. We demonstrate that the robust ferromagnetic state is induced by the oxygen vacancies in SrTiO3- or in the LaAlO3-layer. This allows for the notion that areas with increased density of oxygen vacancies produce ferromagnetic puddles and account for the previous observation of a superparamagnetic behavior in the superconducting state.Comment: 5 pages, 4 figures, to appear in Physical Review B (Rapid Communications

Interface hole-doping in cuprate-titanate superlattices

The electronic structure of interfaces between YBa$_2$Cu$_3$O$_6$ and SrTiO$_3$ is studied using local spin density approximation (LSDA) with intra-atomic Coulomb repulsion (LSDA+U). We find a metallic state in cuprate/titanate heterostructures with the hole carriers concentrated substantially in the CuO$_2$-layers and in the first interface TiO$_2$ and SrO planes. This effective interface doping appears due to the polarity of interfaces, caused by the first incomplete copper oxide unit cell. Interface-induced high pre-doping of CuO$_2$-layers is a key mechanism controlling the superconducting properties in engineered field-effect devices realized on the basis of cuprate/titanate superlattices.Comment: 5 pages, 5 figure

Oxygen vacancies at titanate interfaces: two-dimensional magnetism and orbital reconstruction

We show that oxygen vacancies at titanate interfaces induce a complex multiorbital reconstruction which involves a lowering of the local symmetry and an inversion of t2g and eg orbitals resulting in the occupation of the eg orbitals of Ti atoms neighboring the O vacancy. The orbital reconstruction depends strongly on the clustering of O vacancies and can be accompanied by a magnetic splitting between the local eg orbitals with lobes directed towards the vacancy and interface dxy orbitals. The reconstruction generates a two-dimensional interface magnetic state not observed in bulk SrTiO3. Using generalized gradient approximation (LSDA) with intra-atomic Coulomb repulsion (GGA+U), we find that this magnetic state is common for titanate surfaces and interfaces.Comment: 13 pages, 18 figures, to appear in Physical Review

Sakurai's Object: characterizing the near-infrared CO ejecta between 2003 and 2007

We present observations of Sakurai's Object obtained at 1–5 μm between 2003 and 2007. By fitting a radiative transfer model to an echelle spectrum of CO fundamental absorption features around 4.7 μm, we determine the excitation conditions in the line-forming region. We find 12C/13C = 3.5+2.0−1.5, consistent with CO originating in ejecta processed by the very late thermal pulse, rather than in the pre-existing planetary nebula. We demonstrate the existence of 2.2 × 10−6≤MCO≤ 2.7 × 10−6 M⊙ of CO ejecta outside the dust, forming a high-velocity wind of 500 ± 80 km s−1. We find evidence for significant weakening of the CO band and cooling of the dust around the central star between 2003 and 2005. The gas and dust temperatures are implausibly high for stellar radiation to be the sole contributor