Can inhomogeneties accelerate the cosmic volume expansion?

If expanding and contracting regions coexist in the universe, the speed of the cosmic volume expansion can be accelerated. We construct simple inhomogeneous dust-filled universe models in which the speed of the cosmic volume expansion is accelerated for finite periods. These models are constructed by removing spherical domains from the Einstein-de Sitter universe and filling each domain with a Lemaitre-Tolman-Bondi dust sphere possessing the same gravitational mass as the removed region. This represents an exact solution of the Einstein equations. We find that acceleration of the cosmic volume expansion is realized in some cases when the size of the contracting region is comparable to the horizon radius of the Einstein-de Sitter universe though this model is very different from the universe observed today. This result implies that non-linear general relativistic effects of inhomogeneities are very important to realize the acceleration of the cosmic volume expansion.Comment: 12 pages,5 figures. version published in Progress of Theoretical Physic

Earnings management and the relation with cost of debt of Brazilian public companies

Sob a teoria de agência e as premissas de gerenciamento de resultados, o objetivo do trabalho foi estudar a relação entre o gerenciamento de resultados (GR) e o custo da dívida (Ki) das empresas brasileiras abertas, no período de 1996 a 2007. Os pressupostos levantados, por meio da literatura existente, são de que, almejando melhores condições contratuais, como o custo da dívida, o custo atual ou passado motiva a empresa a gerenciar o resultado corrente para obter melhores condições de custo futuro ou corrente. Dessa forma, as empresas, intencionalmente, procurariam gerenciar seus resultados, motivadas pelo custo da dívida. Todavia, há apoio teórico para que a relação entre essas variáveis seja unidirecional, com o GR influenciando o custo da dívida, sustentando a segunda hipótese. Para chegar ao objetivo, o trabalho utilizou, como proxy de GR, o modelo para cálculo dos accruals discricionários proposto por Kang e Sivaramakrishnan (1995). As análises foram baseadas no teste não-paramétrico U de Mann-Whitney, seguidas do teste de especificação de Hausman para a análise de simultaneidade, finalizando com a regressão com dados dispostos em painel com correção de Newey-West. Os testes de média apontaram para uma relação positiva entre GR e Ki, mas o teste de simultaneidade não indicou haver inter-relação entre as variáveis. Contudo, os resultados das regressões em painel indicaram que o Ki não influencia o GR, mas que há uma relação positiva, em que quanto maior o GR, maior o custo da dívida, ou seja, este é influenciado por aquele.Under agency theory and assumptions of earnings management, the objective is to study the relationship between earnings management (EM) and the cost of debt (Ki) of Brazilian publicly held companies in the period from 1996 to 2007. The assumptions raised through the literature are that targeting better contractual terms, like cost of debt, current or past cost, motivates the company to manage the current result so as to obtain better conditions for current or future cost. Thus, companies, intentionally, would seek to manage their results, motivated by the cost of debt. However, theoretical support for the relationship between these variables would be unidirectional, with EM influencing the cost of debt, supporting the second hypothesis. To reach the objective, the work used the EM model for the discretionary accruals proposed by Kang and Sivaramakrishnan (1995) as a proxy. The tests were based on Mann-Whitney's, nonparametric U test, followed by the Hausman specification test for simultaneity analysis, ending with regression with panel data arranged with Newey-West correction. Tests showed the average for a positive relationship between EM and Ki, but the test did not indicate that there is a simultaneous inter-relationship between variables. The results of the panel regression indicates that Ki does not influence EM, but there is a positive relationship between them, in which the higher the EM, the higher the Ki

STS Observations of Landau Levels at Graphite Surfaces

Scanning tunneling spectroscopy measurements were made on surfaces of two different kinds of graphite samples, Kish graphite and highly oriented pyrolytic graphite (HOPG), at very low temperatures and in high magnetic fields. We observed a series of peaks in the tunnel spectra, which grow with increasing field, both at positive and negative bias voltages. These are associated with Landau quantization of the quasi two-dimensional electrons and holes in graphite in magnetic fields perpendicular to the basal plane. Almost field independent Landau levels fixed near the Fermi energy, which are characteristic of the graphite crystalline structure, were directly observed for the first time. Calculations of the local density of states at the graphite surfaces allow us to identify Kish graphite as bulk graphite and HOPG as graphite with finite thickness effectively

Identification of vasopressin and determination of its corticomedullary levels in rat kidney tissue

Identification of vasopressin and determination of its corticomedullary levels in rat kidney tissue. To investigate the kidney tissue level of arginine vasopressin (AVP), tissue AVP was extracted, identified and assayed. Rat kidney tissue was separated into the papilla (P), medulla (M), and cortex (C). After homogenization, AVP was extracted with acetone and determined by radioimmunoassay. Fractionation of the tissue extract by Sephadex G25 column chromatography showed that the peak of immunoreactive AVP was identical to that of synthetic AVP. There was good correlation between bioassayable and immunoassayable AVP for the tissue extracts. Tissue AVP concentrations (pg/g wet weight) after 36hr of dehydration were: P, 164.3 ± 13.0; M, 93.8 ± 8.4; and C. 28.9 ± 3.9 with a plasma AVP (pg/ml) of 11.7 ± 1.0 (mean ± SE, N = 18). Thus, the papilla/plasma AVP concentration ratio was high. When l25I-AVP was administered, the papilla/plasma ratio was very low. Under water diuresis, the tissue AVP level was very low. The kidney tissue level of dDAVP, which was administered exogenously, was much higher than that of AVP when compared at similar plasma levels. Thus, the present study demonstrated the existence of a corticomedullary concentration gradient of AVP with a medullary level much higher than the plasma level. The accumulation of AVP seemed to result from receptor-mediated processes, since, 125I-AVP, which is biologically inactive and does not bind to hormone receptors, showed only a slight accumulation. The higher tissue level of dDAVP suggested that the tissue level was determined by the balance between accumulation and inactivation. since dDAVP is known to be scarcely inactivated in the kidney.Identification de la vasopressine et détermination de ses niveaux cortico-médullaires dans le tissu rénal de rat. Explorer le niveau tissulaire rénal d'arginine vasopressine (AVP), l'AVP tissulaire a été extraite, identifiée et dosée. Le tissu rénal a été séparé en papille (P), medulla (M), et cortex (C). Après homogénéisation, l*AVP a été extraite avec de l'acétone et déterminée par dosage radioimmunologique. Le fractionnement de l'extrait tissulaire sur colonne de chromatographic de Séphadex G25a montré que le pic d'AVP immunoréactive était identique à celui de l'AVP synthétique. Il y avait une bonne corrélation entre l'AVP dosable biologiquement et immunologiquement dans ces extraits tissulaires. Les concentrations tissulaires d'AVP (pg/g de poids humide) après 36 heures de déshydratation étaient: P, 164,3 ± 13.0; M, 93,8 ± 8.4; et C, 28,9 ± 3.9 avec une AVP plasmatique (pg/ml) de 11,7 ± 1,0 (moyenne ± se, N = 18). Ainsi, le rapport de concentration d'AVP papille/plasma était élevé. Quand de l'125I-AVP était administrée, le rapport papille/plasma était très bas. Lors d'une diurèse aqueuse, le niveau d'AVP tissulaire était très bas. Le niveau tissulaire rénal de dDAVP, qui avait été administré de façon exogène, était bien plus élevé que celui de l'AVP par rapport a un niveau plasmatique identique. Ainsi, cette étude a démontré l'existence d'un gradient de concentration cortico-médullaire d'AVP avec un niveau médullaire bien plus élevé que le niveau plasmatique. L'accumulation d'AVP a semblé résulter de processus ayant un récepteur pour médiateur puisque 125I-AVP, qui est biologiquement inactive et ne se lie pas aux récepteurs hormonaux, n'a présenté qu'une discrète accumulation. Le niveau tissulaire plus élevé de dDAVP suggérait que le niveau tissulaire était déterminé par un équilibre entre l'accumulation et Linactivation la dDAVP étant connue pour être faiblement inactivée par le rein

Conservadorismo incondicional nas companhias abertas brasileiras e o contexto da neutralidade tributária

Law n. 11,638/2007 legitimized the International Financial Reporting Standards (IFRS) adoption process in Brazil and introduced an accounting system detached from tax purposes in the country. This law aims to reduce the influence of tax law on accounting standards and improve the quality of financial reporting, as IFRS are considered to be higher quality standards. International literature shows a reduction in earnings quality in environments where accounting and tax rules are strongly linked. Moreover, the influence of tax legislation on financial accounting is seen to encourage unconditional conservatism, a bias with no advantages for financial market efficiency. Thus, tax neutrality is expected to provide a more favorable institutional environment for quality financial reporting by detaching corporate accounting from tax accounting. In light of the above, this study aims to verify whether the advent of tax neutrality influences unconditional conservatism in Brazilian public companies. The methodology used involves panel data regressions. The sample consists of non-financial publicly-traded companies with information published in Economática® covering 2002 to 2014. The results show differences in the relationship between taxation and financial reporting between firms that are subject to different levels of monitoring in the Brazilian stock market. Evidence of unconditional conservatism is only found in companies that are subject to greater market monitoring. In this group, it is observed that taxation does not induce unconditional conservatism in reported earnings, which is expected in a tax neutrality context.A Lei nº 11.638/2007 (Brasil, 2007) legitimou o processo de adoção das International Financial Reporting Standards (IFRS) no Brasil e introduziu um regime contábil desvinculado da finalidade tributária no país. Dentre os objetivos da referida lei estão a redução da influência da legislação fiscal nas normas contábeis e a melhora na qualidade do reporte financeiro, uma vez que as IFRS são consideradas normas de qualidade superior. A literatura internacional apresenta evidências de redução no poder informativo dos lucros em ambientes nos quais normas contábeis e tributárias estão fortemente vinculadas. Ademais, a influência da legislação fiscal sobre a contabilidade financeira é apontada como incentivo ao conservadorismo incondicional, viés que não apresenta vantagens à eficiência dos mercados financeiros. Assim, infere-se que a neutralidade tributária pode proporcionar um ambiente institucional mais favorável ao reporte financeiro de qualidade ao desvincular a contabilidade societária da contabilidade fiscal. Diante do exposto, o presente artigo tem o objetivo de verificar se o advento da neutralidade tributária influencia o conservadorismo incondicional nas companhias abertas brasileiras. A metodologia utilizada envolve regressões para dados em painel. A amostra é composta por companhias não financeiras de capital aberto com informações divulgadas na Economatica® no período de 2002 a 2014. Os resultados evidenciam diferenças na relação entre tributação e reporte financeiro entre firmas sujeitas a diferentes graus de monitoramento no mercado acionário brasileiro. São encontrados indícios de conservadorismo incondicional em empresas sujeitas a maior monitoramento de mercado, apenas. Neste grupo, observa-se que a tributação não induz o conservadorismo incondicional nos lucros divulgados, o que é esperado em um contexto de neutralidade tributária

Collective Phase Sensitivity

The collective phase response to a macroscopic external perturbation of a population of interacting nonlinear elements exhibiting collective oscillations is formulated for the case of globally-coupled oscillators. The macroscopic phase sensitivity is derived from the microscopic phase sensitivity of the constituent oscillators by a two-step phase reduction. We apply this result to quantify the stability of the macroscopic common-noise induced synchronization of two uncoupled populations of oscillators undergoing coherent collective oscillations.Comment: 6 pages, 3 figure

Charge-Order Pattern of the Low-Temperature Phase of NaV2O5 Uniquely Determined by Resonant X-Ray Scattering from Monoclinic Single Domain

The present resonant x-ray scattering from each of monoclinically-split single domains of NaV2O5 has critically enhanced contrast between V4+ and V5+ ions strong enough to lead to unambiguous conclusion of the charge-order pattern of its low-temperature phase below Tc = 35 K. The zig-zag type charge-order patterns in the $ab$-plane previously confirmed have four kinds of configurations (A, A', B and B') and the stacking sequence along the c-axis is determined as the AAA'A' type by comparison with model calculations. By assigning the A and A' configurations to Ising spins, one can reasonably understand the previously discovered "devil's staircase"-type behavior with respect to the modulation of the layer-stacking sequences at high pressures and low temperatures, which very well resembles the global phase diagram theoretically predicted by the ANNNI model.Comment: 4 pages, 3 figure

Relation Between Moisture Sorption and Hygroexpansion of Sitka Spruce During Adsorption Processes

Moisture adsorption processes carried out in successive steps at three increasing levels of RH (45, 75, 85%) at 20°C for Sitka spruce (Picea sitchensis Carr.) were studied. Moisture content and dimensional changes in radial and tangential directions of the specimens were measured and it was found that moisture changes were slower than dimensional. The modeling on this moisture-dimensional relationship, based on the idea of dividing sorbed water into two components having different effects on dimensional changes, not only shows a good agreement with experimental results, but also presents a new understanding of the mechanism of hygroexpansion of wood

Heterogeneity in earnings quality between different classes of companies after IFRS adoption: evidence from Brazil

Este trabalho tem como objetivo investigar a existência de heterogeneidade na qualidade do lucro contábil entre diferentes classes de empresas com a adoção das normas internacionais de contabilidade [International Financial Reporting Standards (IFRS)]. A adoção de IFRS está geralmente associada ao aumento de qualidade das demonstrações contábeis. Entretanto, as empresas de um mesmo país provavelmente possuem diferentes incentivos econômicos em relação à divulgação da informação. Neste sentido, tratar as empresas de forma homogênea, sem considerar os incentivos econômicos atrelados, poderia contaminar a investigação da qualidade do lucro. É analisado o caso do Brasil, país classificado como code-law, cuja legislação fiscal induzia a prática contábil e com adoção mandatória de IFRS. Em primeiro lugar, as empresas brasileiras listadas na Bolsa de Valores, Mercadorias e Futuros de São Paulo foram separadas em duas classes: as empresas que possuíam títulos no mercado internacional [American Depositary Receipt (ADR)] antes da adoção de IFRS e as empresas que não emitiram ADR até a adoção de IFRS. Em seguida, esta segunda classe de empresas foi segregada, por meio de análise de conglomerados, em duas diferentes subclasses em função de incentivos econômicos. Com base nas três classes identificadas, é testada a qualidade do lucro contábil para cada classe de empresas antes e após a adoção de IFRS no período de 2003 a 2014. Este trabalho utiliza o reconhecimento tempestivo dos eventos econômicos, a value relevance do lucro contábil e o gerenciamento de resultados como proxies para verificar a qualidade do lucro contábil. Os resultados encontrados indicam que um determinado conjunto de empresas passou a exibir conservadorismo condicional, value relevance do lucro contábil e menor gerenciamento de resultados após a adoção de IFRS. Em contrapartida, estes resultados não foram encontrados para as duas outras classes de empresas.This paper aims to investigate the existence of heterogeneity in earnings quality between different classes of companies after the adoption of the International Financial Reporting Standards (IFRS). IFRS adoption is generally associated with an increase in the quality of financial statements. However, companies within the same country are likely to have different economic incentives regarding the disclosure of information. Thus, treating companies equally, without considering the related economic incentives, could contaminate earnings quality investigations. The case of Brazil is analyzed, which is a country classified as code-law, in which tax laws determined accounting practice and in which IFRS adoption is mandatory. First, Brazilian companies listed on the São Paulo Stock, Commodities, and Futures Exchange (BM&FBOVESPA) were separated into two classes: companies issuing American Depositary Receipts (ADRs) before IFRS adoption and companies that did not issue ADRs until the adoption of IFRS. Then, this second class of companies was grouped, using cluster analysis, into two different subclasses according to economic incentives. Based on the groups identified, the quality of accounting earnings is tested for each class of the companies before and after IFRS adoption. This paper uses timely recognition of economic events, value relevance of net income, and earnings management as proxies for the quality of accounting earnings. The results indicate that a particular class of companies began showing conditional conservatism, value relevance of net income, and lower earnings management after IFRS adoption. On the other hand, these results were not found for the two other classes of companies