Monte Carlo Simulations of Ultrathin Magnetic Dots

In this work we study the thermodynamic properties of ultrathin ferromagnetic dots using Monte Carlo simulations. We investigate the vortex density as a function of the temperature and the vortex structure in monolayer dots with perpendicular anisotropy and long-range dipole interaction. The interplay between these two terms in the hamiltonian leads to an interesting behavior of the thermodynamic quantities as well as the vortex density.Comment: 10 figure

Hamiltonian thermodynamics of three-dimensional dilatonic black holes

The action for a class of three-dimensional dilaton-gravity theories with a cosmological constant can be recast in a Brans-Dicke type action, with its free $\omega$ parameter. These theories have static spherically symmetric black holes. Those with well formulated asymptotics are studied through a Hamiltonian formalism, and their thermodynamical properties are found out. The theories studied are general relativity ($\omega\to\infty$), a dimensionally reduced cylindrical four-dimensional general relativity theory ($\omega=0$), and a theory representing a class of theories ($\omega=-3$). The Hamiltonian formalism is setup in three dimensions through foliations on the right region of the Carter-Penrose diagram, with the bifurcation 1-sphere as the left boundary, and anti-de Sitter infinity as the right boundary. The metric functions on the foliated hypersurfaces are the canonical coordinates. The Hamiltonian action is written, the Hamiltonian being a sum of constraints. One finds a new action which yields an unconstrained theory with one pair of canonical coordinates $\{M,P_M\}$, $M$ being the mass parameter and $P_M$ its conjugate momenta The resulting Hamiltonian is a sum of boundary terms only. A quantization of the theory is performed. The Schr\"odinger evolution operator is constructed, the trace is taken, and the partition function of the canonical ensemble is obtained. The black hole entropies differ, in general, from the usual quarter of the horizon area due to the dilaton.Comment: 34 pages, 3 figures, references added, minor changes in the revised versio

International Accounting Standards Board: An examination of the main financial and accounting topics addressed in the literature related to the COVID-19 pandemic

The International Accounting Standards Board (IASB) conducts very demanding and complex work to setting accounting standards. The outputs produced by this board and their acts have been scrutinized over the years, by practitioners and academics. This study aims to contribute to the knowledge on the role of IASB by unveiling the research trends address­ing this group of accounting experts and its publications. Through the anal­ysis of the bibliometric data related to COVID-19 issues, this study identifies the main topics addressed in the literature during this pandemic. The results contribute to assessing the research conducted in this field and for creating the future research agenda on addressing the role and impact of the IASB during health, social and economic crises.info:eu-repo/semantics/publishedVersio

Desempenho produtivo de ovinos da raça Santa Inês, no Acre.

Visando avaliar a adaptabilidade e determinar as médias de produção dos ovinos da raça Santa Inês, nas condições climáticas do Acre, foram adquiridos do Nordeste do Brasil 40 matrizes e dois reprodutores desta raça, os quais foram criados semi-extensivamente, tendo como base alimentar pastagem cultivada de Brachiaria humidicola (quicuio-da-amazônia). o sistema de acasalamento foi a monta natural a campo, onde o macho permaneceu com as fêmeas o ano todo. Após quatro anos de estudos, obteve-se os seguintes índices produtivos: taxa de fertilidade ao parto, 83,1%; prolificidade, 1,24 cordeiros nascidos/parto/ano; taxa de natalidade, 123%. A mortalidade de crias de zero a seis meses de idade foi 16,2%. Ocorreram parições durante todos os meses do ano, com uma maior concentração no período de junho a outubro (55,36%). A ocorrência de partos duplos e triplos foi 21,38% e 1,26%, respectivamente. O intervalo entre partos foi de 260,8 ± 80,6 dias. O peso médio ao nascer foi de 2,95 ± 0,77 e 2,86 ± 0,68 para machos e fêmeas, respectivamente. Os dados evidenciam um bom desempenho do rebanho, principalmente no que diz respeito à afta taxa de sobrevivência de crias na faixa etária de zero a seis meses, curto intervalo entre partos e afta taxa de fertilidade.bitstream/item/161365/1/3993.pd

COVID-19 research streams emerging in International Financial Reporting Standards related studies

Interpretation for the adoption of the International Financial Reporting Standards (IFRS) became to be challenging for organizations. Over time, these standards are changed to accommodate the improvements identified in accounting rules. COVID-19 pandemic impacted accounting reporting considering that contingencies and risks arising from this health crisis should be reported to stakeholders. In order to provide empirical evidence of the most important COVID-19 related practical and academic issues and challenges addressed by academics when reporting under IFRS, this study applies an automated computer-aided analysis for clustering the bibliometric data published concerning IFRS and COVID-19. The results support academic studies and practitioners by identifying the COVID-19 research streams that received the most attention in 2020. This study also suggests guidelines for future research that derive from past academic contributions.info:eu-repo/semantics/publishedVersio

Trends in the management accounting research: A review of the literature published during the COVID-19 pandemic

Management accounting theory aims to contribute to managers using accounting reports for supporting their management decisions. During the COVID-19 pandemic, such insights would be essential for supporting decisions during lockdowns and other policy makers’ rules imposed by this health crisis. To unveil how academic literature addresses management accounting challenges arising from the COVID-19 specific context, this study conducts an automated computer analysis of the bibliometric data addressing financial issues related to the COVID-19 pandemic.info:eu-repo/semantics/publishedVersio

X, Y and Z States

Many new states in the charmonium mass region were recently discovered by BaBar, Belle, CLEO-c, CDF, D0, BESIII, LHCb and CMS Collaborations. We use the QCD Sum Rule approach to study the possible structure of some of these states.Comment: Contribution for the proceedings of the "XII Quark Confinement and the Hadron Spectrum - CONF12" conferenc

Half Quantization

A general dynamical system composed by two coupled sectors is considered. The initial time configuration of one of these sectors is described by a set of classical data while the other is described by standard quantum data. These dynamical systems will be named half quantum. The aim of this paper is to derive the dynamical evolution of a general half quantum system from its full quantum formulation. The standard approach would be to use quantum mechanics to make predictions for the time evolution of the half quantum initial data. The main problem is how can quantum mechanics be applied to a dynamical system whose initial time configuration is not described by a set of fully quantum data. A solution to this problem is presented and used, as a guideline to obtain a general formulation of coupled classical-quantum dynamics. Finally, a quantization prescription mapping a given classical theory to the correspondent half quantum one is presented.Comment: 20 pages, LaTex file, Substantially revised versio