TAX COSTS AND CORPORATION DIVIDEND POLICY: Evidence from the 1986 U.S. Tax Reform Acts

Scholes and Wolfson (1992) predict that following the 1986 TaxReform Act, the tax cost of the corporate form relative to that of the partnership form (the incremental tax cost) increased significantly. This study hypothesizes that since dividends represent a tax disadvantaged form of income relative to capital gains, then in response to an increase in incremental tax costs, corporations would decrease their dividend payout ratios. The response is expected to be stronger for corporations owned byshareholders with long investment horizons because the tax cost saved from decreasing dividend payout ratios is an increasing function of shareholders’ investment horizon. The empirical tests support the hypothesis and show a negative relationship between the change in incremental tax costs and the change in dividend payout ratios for firms with long average investment horizons

The Demand for New Cars and the Index of Consumer Sentiment

The index ofconsumer sentiment (ICS) has been widely employed as a proxy for future buying confidence to predict future aggregate buying behavior. This study empirically compares two forecast models: the expectation model thatincludes the ICS as an explanatory variable and the traditional model that does not include the ICS. The models are employed to estimate the aggregate demand for new cars in the U.S. from 1976 to 1984. The results indicate that the ICS has a positive relation with new car sales. On the basis of the likelihood dominance criterion, however, the traditional model is preferred to the expectation model. Furthermore, the forecast ability of the expectation model is slightly inferior to the traditional mode

Spin transport in high-mobility graphene on WS2 substrate with electric-field tunable proximity spin-orbit interaction

Graphene supported on a transition metal dichalcogenide substrate offers a novel platform to study the spin transport in graphene in presence of a substrate induced spin-orbit coupling, while preserving its intrinsic charge transport properties. We report the first non-local spin transport measurements in graphene completely supported on a 3.5 nm thick tungsten disulfide (WS$_2$) substrate, and encapsulated from the top with a 8 nm thick hexagonal boron nitride layer. For graphene, having mobility up to 16,000 cm$^2$V$^{-1}$s$^{-1}$, we measure almost constant spin-signals both in electron and hole-doped regimes, independent of the conducting state of the underlying WS$_2$ substrate, which rules out the role of spin-absorption by WS$_2$. The spin-relaxation time $\tau_{\text{s}}$ for the electrons in graphene-on-WS$_2$ is drastically reduced down to~10 ps than $\tau_{\text{s}}$ ~ 800 ps in graphene-on-SiO$_2$ on the same chip. The strong suppression of $\tau_{\text{s}}$ along with a detectable weak anti-localization signature in the quantum magneto-resistance measurements is a clear effect of the WS$_2$ induced spin-orbit coupling (SOC) in graphene. Via the top-gate voltage application in the encapsulated region, we modulate the electric field by 1 V/nm, changing $\tau_{\text{s}}$ almost by a factor of four which suggests the electric-field control of the in-plane Rashba SOC. Further, via carrier-density dependence of $\tau_{\text{s}}$ we also identify the fingerprints of the D'yakonov-Perel' type mechanism in the hole-doped regime at the graphene-WS$_2$ interface.Comment: 11 pages, 7 figure

¿CÓMO SE ENSEÑA Y ESTUDIA HISTORIA HOY EN LAS ESCUELAS NORMALES PÚBLICAS DE MÉXICO? UNA APROXIMACIÓN DESDE LAS MIRADAS DE LOS ESTUDIANTES

En este texto se presentan algunos resultados de la investigación «¿Cómo se aprende y estudia Historia hoy en las escuelas normales mexicanas? Una aproximación desde las miradas de los estudiantes», que fue desarrollada entre los años 2010 y 2011. Esta investigación tuvo como propósito realizar una aproximación a los conocimientos y nociones que adquieren los estudiantes normalistas sobre la disciplina y su docencia a lo largo de sus estudios profesionales. La pregunta eje de este trabajo fue: ¿cómo se estudia Historia actualmente en las escuelas normales? Como parte de la investigación, se aplicó una encuesta (la primera de este tipo y alcance que se realiza en México) a 2.598 estudiantes de las licenciaturas en Educación Primaria y en Educación Secundaria con especialidad en Historia en 65 escuelas normales públicas del país. Aquí se analizan las respuestas que se refieren a las relaciones -siempre complejas y abiertas al debate- de los rasgos identitarios que los alumnos asumen en relación con su perfil sociodemográfico, las regiones en las que habitan y sus visiones sobre la disciplina. Resalta, en gran medida, el contraste entre una identidad abierta en términos de pertenencia regional y la concepción histórica que ha predominado en nuestro país, orientada a crear y consolidar los vínculos identitarios a partir de la Nación como lazo que une a todos los mexicanos. Las conclusiones cuestionan la validez de una formación histórica que no parece hacer mella en las concepciones de los jóvenes mexicanos, en este caso en los estudiantes de las escuelas normales. Además, y dada la aparente confusión en torno a elementos teóricos y contenidos históricos, las conclusiones del presente artículo sugieren la necesidad de enfatizar y profundizar la formación de los futuros maestros de Primaria y Secundaria en cuanto a la epistemología de la Historia, sus contenidos y la pedagogía específica de la disciplin

Spin transport and relaxation in graphene, functionalized-graphene & graphene-TMD heterostructures

Grafeen is een één-atomig dik koolstofmateriaal, bekend om zijn uitzonderlijke elektronische eigenschappen die kunnen worden gebruikt in de toekomstige elektronica-industrie. Ook heeft het een grote potentie voor het dragen van het spin-hoekmoment van het elektron over lange afstanden, waardoor het materiaal te gebruiken is voor 'spintronica' waar elektronenspins dienen als informatiedragers. In dit proefschrift bestudeer ik twee fundamentele problemen in spintronische apparaten op basis van grafeen: ten eerste, welke factoren het spintransport in grafeen beïnvloeden en ten tweede, hoe de spinstroom in grafeen te regelen is. Om deze problemen te bestuderen, voeren wij spin-transport experimenten uit in verschillende apparaatarchitecturen. We hebben gevonden dat magnetische onzuiverheden doorslaggevend zijn voor het spin-transport door de spintronische eigenschappen van grafeen in combinatie met magnetische porfyrinemoleculen te meten. Verder hebben we spinafhankelijke ruismetingen uitgevoerd in grafeen en vinden we dat de grootte van de spinruis drie tot vier ordes hoger is dan de grootte van het elektronische ruis. We schrijven dit gedrag toe aan onzuiverheden die de elektronspins sterker verstrooien dan elektronische lading. Om de spinstroom in grafeen te regelen, combineren we grafeen met een ander 2D-materiaal, wolfraamdisulfide (WS2) en fabriceren we grafeen-WS2 heterostructuren. We hebben uitgevonden dat spin-transport sterk wordt onderdrukt in grafeen dat in contact staat met WS2 als gevolg van de versterking van spin-baankoppeling in grafeen. Deze eigenschap kan ook worden geregeld via een extern elektrisch veld. De verkregen resultaten kunnen worden gebruikt om de prestaties van toekomstige op grafeen gebaseerde spintronische apparaten te verbeteren en om de eerste op grafeen gebaseerde spin-transistor te demonstreren.Graphene is a one-atom-thick carbon material, known for its exceptional electronic properties, which can be utilized in the future electronics industry. Also, it has shown a great potential for carrying the spin-angular momentum of electron up to long distances, making it useful in the field of ‘spintronics’ where electron-spins serve as information carriers. In this thesis, I study two fundamental problems in graphene-based spintronic devices: first, which factors affect the spin-transport in graphene and second, how to control the spin-current in graphene. In order to address these issues, we perform spin-transport experiments in various device architectures. We find that magnetic impurities are detrimental to the spin-transport, which we confirm by measuring the spintronic properties of graphene, decorated with magnetic porphyrin molecules. Alternatively, we also perform spin-dependent noise measurements in graphene and find that the spin-noise magnitude is higher by three-to-four orders than the charge noise magnitude. We attribute this behaviour to impurities scattering the electron-spins more severely than electronic-charge. In order to control the spin-current in graphene, we combine graphene with another 2D-material, tungsten disulfide (WS2), and fabricate graphene-WS2 heterostructures. We find that spin-transport is greatly suppressed in graphene which is in contact with WS2 due to the enhancement of spin-orbit coupling in graphene. This property can also be controlled via external electric-field. The obtained results can be utilized to improve the performance of future graphene-based spintronic-devices and to demonstrate the first graphene-based spin-transistor

SÚMULAS VINCULANTES: ESTUDO DE CASOS E PARÂMETROS PARA CRIAÇÃO, REVISÃO E CANCELAMENTO

Na segunda seção, relativa ao Laboratório de Jurisprudência, serão apresentados estudos de alguns dos casos de maior destaque ao longo dos vinte anos da Constituição de 1988. Foram escolhidos o caso Collor, as decisões judiciais sobre as pesquisas com células-tronco e as primeiras súmulas-vinculantes

The Potosí principle: religious prosociality fosters selforganization of larger commnities under extreme natural and economic conditions

We show how in colonial Potosı´ (present-day Bolivia) social and political stabil-ity was achieved through the self-organization of society through the repetition of religious rituals. Our analysis shows that the population of Potosı´ develops over the time a series of cycles of rituals and miracles as a response to social upheaval and natural disasters and that these cycles of religious performance become crucial mechanisms of cooperation among different ethnic and religious groups. Our methodology starts with a close reading and annotation of the Historia de Potosı´ by Bartolome´ Arzans. Then, we model the religious cycles of miracles and rituals and store all social and cultural information about the cycles in a multirelational graph database. Finally, we perform graph analysis through traversals queries in order to establish facts concerning social networks, historical evolution of behaviors, types of participation of miraculous characters according to dates, parts of the city, ethnic groups, etc. It is also important to note that the religious activity at the group level gave native communities a way to participate in the social life. It also guaranteed that the city performed its role as producer of silver in the global economic structure of the Spanish empire. This case proves the importance of religion as a mechanism of stability and self-organization in periods of social or political turbulence. The multidisciplinary methodology combining traditional humanistic techniques with graph analysis shows a great potential for other sociological, historical, and literary problems

PLINIO NOMELLINI 1866-1943. ICONOGRAFIE DEL LAVORO. DAL REALISMO SOCIALE AL SIMBOLISMO 1885-1908

Il presente studio intende proporre una rilettura originale della pittura di Nomellini, fondata su un percorso critico incentrato sulle iconografie del lavoro. Tale analisi è limitata cronologicamente alla prima fase della sua attività: dagli esordi fiorentini, intorno al 1886, alle partecipazioni alla Biennale di Venezia nelle edizioni del 1907 e del 1909. Si intende così definire un ideale catalogo delle opere dedicate al tema del lavoro capace di ripercorrere e di precisare quell’evoluzione estetico-ideologica già messa in luce da Ragghianti, che aveva portato diversi artisti inizialmente ispirati a ideali sociali umanitaristi dapprima verso una «significazione idealista» di carattere dannunziano e poi all’adesione a un mitografismo nazionalista e «immaginifico». Uno sviluppo che nel caso di Nomellini parte da dipinti che ritraggono i contadini della Maremma secondo una prospettiva sociale umanitaria e con uno stile ancora in bilico tra il naturalismo e la rappresentazione di un nuovo senso della luce, e che trova un provvisorio punto d’arrivo nelle tele genovesi di dichiarata critica sociale, realizzate con la tecnica divisionista. Se la svolta simbolista di Nomellini comporta anche la scomparsa del tema del lavoro dalla sua pittura, l’iconografia del lavoro si ripresenta nuovamente nella produzione nomelliniana del primo decennio del Novecento, trasfigurata però da una nuova prospettiva ideologica tesa a una mitizzazione nazionalista del mondo del lavoro e dei lavoratori e affrontata con un divisionismo ormai maturo.The present study intends to propose an original reinterpretation of Nomellini's painting, based on a critical path centered on the iconographies of work. This analysis is chronologically limited to the first phase of his activity: from the Florentine beginnings, around 1886, to the participations in the Venice Biennale in the 1907 and 1909 editions. Thus we intend to define an ideal catalog of works dedicated to the theme of work capable of retrace and clarify that aesthetic-ideological evolution already highlighted by Ragghianti, which had led several artists initially inspired by humanitarian social ideals, first towards an "idealist signification" of a D'Annunzian character and then adherence to a nationalist and "imaginative mythography ". A development that in Nomellini's case starts from paintings that portray the peasants of the Maremma according to a humanitarian social perspective and with a style still poised between naturalism and the representation of a new sense of light, and which finds a provisional point of arrival in the Genoese canvases of declared social criticism, made with the pointillist technique. If Nomellini's symbolist turning point also entails the disappearance of the theme of work from his painting, the iconography of work reappears again in Nomellini's production of the first decade of the twentieth century, transfigured, however, by a new ideological perspective aimed at a nationalist mythization of the world of work and workers and faced with a mature divisionism