Magnetic properties of the three-band Hubbard model

We present magnetic properties of the three-band Hubbard model in the para- and antiferromagnetic phase on a hypercubic lattice calculated with the Dynamical Mean-Field Theory (DMFT). To allow for solutions with broken spin-symmetry we extended the approach to lattices with AB-like structure. Above a critical sublattice magnetization m_d=0.5 one can observe rich structures in the spectral-functions similar to the t-J model which can be related to the well known bound states for one hole in the Neel-background. In addition to the one-particle properties we discuss the static spin-susceptiblity in the paramagnetic state at the points q=0 and q=(pi,pi,pi,...) for different dopings delta. The delta-T-phase-diagram exhibits an enhanced stability of the antiferromagnetic state for electron-doped systems in comparison to hole-doped. This asymmetry in the phase diagram is in qualitative agreement with experiments for high-T_c materials.Comment: revised version, to be publishe

ВЕНДИНГОВИЙ СТАРТАП НА УКРАЇНСЬКОМУ РИНКУ

Vending is a type of retailing, which means selling products and services through automated systems (vending machines (vendors) or terminals). Currently issues of improving vending services considering current market trends and specifics are not sufficiently investigated neither in theoretical nor in practical aspects, which determines the relevance of the research. The authors have described the essence and meaning of the term "vending" and its role. Global trends in this market segment are analyzed as well. The relevance of the vending startup on the domestic market and major segments of vending in Ukraine are highlighted. The main benefits of the introduction of vending startup for an entrepreneur are systematized. Entry barriers to this market and the approximate size of the required initial capital are highlighted. A range of vending machines and their pricing is analyzed, and the formula to calculate the payback period of the vending startup is highlighted. Essential stages of implementation of the vending business are provided. The possible dangers that may arise during the vendor operations are described. Based on the research we can conclud that vending is a profitable and promising business in Ukraine. In comparison to traditional retailing vending has many advantages, including: 1) no costs for office and storage space maintenance, – they are not needed, 2) involvement of minimum human resources, – a salesman is not needed for the machine, 3) easy business from the legal point of view, – special permits are not necessary, simplified taxation scheme is applicable. Modern vending – is not only a promising and profitable type of business but also innovative technologies. Today vending business in Ukraine is highly segmented and underdeveloped (niche occupancy is 15-20 %), has huge prospects, there are unoccupied market niches. It is quite easy to open vending business compared to other forms of small business. On average payback period of a vending machine is 1-1.5 years. The highest returns can be provided by devices with high mark-up goods. Service life of vending machines can be up to 10 years, so after providing payback they can generate income for many years. Developed network of vending machines is fully capable to provide its owner with high and stable incomes.Рассмотрены сущность и значение вендинга, а также приведены мировые тенденции развития этого сегмента рынка. Проанализирована актуальность вендингового стартапа на отечественном рынке и приведены основные сегменты вендинга в Украине. Рассмотрены основные преимущества при внедрении такого стартапа для предпринимателя. Приведены барьеры входа на рынок и выделен примерный размер необходимого стартового капитала. Детально проанализированы ассортимент торговых автоматов и их ценовая политика, а также выделена формула для расчета срока окупаемости вендингового стартапа. Приведены необходимые этапы внедрения вендингового бизнеса. Также рассмотрены возможные опасности, которые могут возникнуть в ходе эксплуатации вендоров.Розглянуто сутність та значення вендингу, а також наведено світові тенденції розвитку цього сегмента ринку. Проаналізовано актуальність вендингового стартапу на вітчизняному ринку та наведено основні сегменти вендингу в Україні. Розглянуто основні переваги при впровадженні такого стартапу для підприємця. Наведено бар’єри входу на ринок і виділено приблизний розмір необхідного стартового капіталу. Детально проаналізовано асортимент торгових автоматів та їхню цінову політику, а також виділено формулу для розрахунку терміну окупності вендингового стартапу. Наведено потрібні етапи впровадження вендингового бізнесу. Також розглянуто можливі небезпеки, які можуть виникнути у ході експлуатації вендорів

A novel method for adult height prediction in children with idiopathic short stature derived from a German-Dutch cohort

Context: Prediction of adult height (AH) is important in clinical management of short children. The conventional methods of Bayley-Pinneau (BP) or Roche-Wainer-Thissen (RWT) have limitations. Objective: We aimed to develop a set of algorithms for AH prediction in patients with idiopathic short stature (ISS) which are specific for combinations of predicting variables. Methods: Demographic and auxologic data were collected in childhood (1980s) and at AH (1990s). Data were collected by Dutch and German referral centers for pediatric endocrinology. A total of 292 subjects with ISS (219 male, 73 female) were enrolled. The population was randomly split into modeling (n = 235) and validation (n = 57) cohorts. Linear multi-regression analysis was performed with predicted AH (PAH) as response variable and combinations of chronological age (CA), baseline height, parental heights, relative bone age (BA/CA), birth weight, and sex as exploratory variables. Results: Ten models including different exploratory variables were selected with adjusted R-2 ranging from 0.84 to 0.78 and prediction errors from 3.16 to 3.68 cm. Applied to the validation cohort, mean residuals (PAH minus observed AH) ranged from -0.29 to -0.82 cm, while the conventional methods showed some overprediction (BP: +0.53 cm; RWT: +1.33 cm; projected AH: +3.81 cm). There was no significant trend of residuals with PAH or any exploratory variables, in contrast to BP and projected AH. Conclusion: This set of 10 multi-regression algorithms, developed specifically for children with ISS, provides a flexible tool for AH prediction with better accuracy than the conventional methods.Developmen

Residual cognitive deficits 50 years after lead poisoning during childhood

The long term neurobehavioural consequences of childhood lead poisoning are not known. In this study adult subjects with a documented history of lead poisoning before age 4 and matched controls were examined with an abbreviated battery of neuropsychological tests including measures of attention, reasoning, memory, motor speed, and current mood. The subjects exposed to lead were inferior to controls on almost all of the cognitive tasks. This pattern of widespread deficits resembles that found in children evaluated at the time of acute exposure to lead rather than the more circumscribed pattern typically seen in adults exposed to lead. Despite having completed as many years of schooling as controls, the subjects exposed to lead were lower in lifetime occupational status. Within the exposed group, performance on the neuropsychological battery and occupational status were related, consistent with the presumed impact of limitations in neuropsychological functioning on everyday life. The results suggest that many subjects exposed to lead suffered acute encephalopathy in childhood which resolved into a chronic subclinical encephalopathy with associated cognitive dysfunction still evident in adulthood. These findings lend support to efforts to limit exposure to lead in childhood

Complementarity in classical dynamical systems

The concept of complementarity, originally defined for non-commuting observables of quantum systems with states of non-vanishing dispersion, is extended to classical dynamical systems with a partitioned phase space. Interpreting partitions in terms of ensembles of epistemic states (symbols) with corresponding classical observables, it is shown that such observables are complementary to each other with respect to particular partitions unless those partitions are generating. This explains why symbolic descriptions based on an \emph{ad hoc} partition of an underlying phase space description should generally be expected to be incompatible. Related approaches with different background and different objectives are discussed.Comment: 18 pages, no figure

Magnetic Field Effects on Neutron Diffraction in the Antiferromagnetic Phase of UPt3UPt_3

We discuss possible magnetic structures in UPt$_3$ based on our analysis of elastic neutron-scattering experiments in high magnetic fields at temperatures $T<T_N$. The existing experimental data can be explained by a single-{\bf q} antiferromagnetic structure with three independent domains. For modest in-plane spin-orbit interactions, the Zeeman coupling between the antiferromagnetic order parameter and the magnetic field induces a rotation of the magnetic moments, but not an adjustment of the propagation vector of the magnetic order. A triple-{\bf q} magnetic structure is also consistent with neutron experiments, but in general leads to a non-uniform magnetization in the crystal. New experiments could decide between these structures.Comment: 5 figures included in the tex

Characterization of halogen-bridged binuclear metal complexes as hybridized two-band materials

We study the electronic structure of halogen-bridged binuclear metal (MMX) complexes with a two-band Peierls-Hubbard model. Based on a symmetry argument, various density-wave states are derived and characterized. The ground-state phase diagram is drawn within the Hartree-Fock approximation, while the thermal behavior is investigated using a quantum Monte Carlo method. All the calculations conclude that a typical MMX compound Pt_2(CH_3CS_2)_4I should indeed be regarded as a d-p-hybridized two-band material, where the oxidation of the halogen ions must be observed even in the ground state, whereas another MMX family (NH_4)_4[Pt_2(P_2O_5H_2)_4X] may be treated as single-band materials.Comment: 16 pages, 11 figures embedded, to be published in Phys. Rev.

Come back Marshall, all is forgiven? : Complexity, evolution, mathematics and Marshallian exceptionalism

Marshall was the great synthesiser of neoclassical economics. Yet with his qualified assumption of self-interest, his emphasis on variation in economic evolution and his cautious attitude to the use of mathematics, Marshall differs fundamentally from other leading neoclassical contemporaries. Metaphors inspire more specific analogies and ontological assumptions, and Marshall used the guiding metaphor of Spencerian evolution. But unfortunately, the further development of a Marshallian evolutionary approach was undermined in part by theoretical problems within Spencer's theory. Yet some things can be salvaged from the Marshallian evolutionary vision. They may even be placed in a more viable Darwinian framework.Peer reviewedFinal Accepted Versio