Standard Model Extension with Flipped Generations

An extension of the Standard Model is presented that leads to the possible existence of new gauge bosons with masses in the range of a few TeV. Due to the fact that their couplings to Standard Model fermions are strongly suppressed, it is possible for them to be hidden from current searches. The model contains additional generations of fermions with quantum numbers resembling those of the Standard Model fermion generations but with a twist: their charge assignments are such that their electric charges and chiralities are flipped with respect to those of their corresponding Standard Model counterparts. This feature provides a way to obtain potential dark matter candidates and the interesting possibility for a Lepton number conserving dimension-five operator for Dirac neutrino masses. The model implications associated to electroweak precision parameters, flavor changing neutral currents, and diphoton rate contributions are briefly discussed. The general assumptions of this set up are also used to sketch a couple of variants of the model with peculiar features that could motivate further study.Comment: 8 pages, 3 figures, 2 tables. Discussion on W' boson and RH neutrinos extended, references added, typos corrected, title changed. Matches published version in PL

Macroeconomic policies for structural adjustment

Structural adjustment is an economy wide adjustment effort aimed at allocating resources better. The author contends that functioning markets and a low, stable inflation rate are two macroeconomic preconditions for implementing structural adjustment. He further concludes that in highly distorted economies the market system must be restored before adjustment efforts are undertaken. Fiscal deficits are probably a key determinant of trade deficits - particularly when the fiscal deficit is financed abroad. This paper is concerned with the identification of macroeconomic policies consistent with the long run sustainability of a stable market framework or with changes that may be required as a consequence of the implementation of the structural adjustment program. It is not directly concerned with issues of short run stabilization, although those issues, particularly that of the timing of policies are mentioned whenever relevant.Economic Stabilization,Environmental Economics&Policies,Economic Theory&Research,Macroeconomic Management,Banks&Banking Reform

The external effects of public sector deficits

This paper develops a two equation model for measuring how public sector deficits - and the way that they are financed - affect the real exchange rate, the trade balance, the current account and the level of external indebtedness. One equation relates the real exchange rate to the trade surplus and the other describes the trade surplus as a function of structural parameters, the fiscal deficit, and the stock of foreign assets. To make the model dynamic, one must allow for the fact that the level of foreign assets - one determinant of the trade surplus and current account - changes over time. The trade surplus, plus foreign internest earned, determines the evolution over time of the stock of foreign assets. Using this model, the paper makes the following conclusions. The level and composition of government spending affects the real exchange rate because of the effect of spending on nontraded goods. Changes in the trade balance are also bound to affect the real exchange rate. How much depends on how much expenditure must be switched to make the trade balance compatible with the change in aggregate spending.Economic Theory&Research,Economic Stabilization,Environmental Economics&Policies,Macroeconomic Management,Public Sector Economics&Finance

Superselection Sectors in Asymptotic Quantization of Gravity

Using the continuity of the scalar $\Psi_2$ (the mass aspect) at null infinity through $i_o$ we show that the space of radiative solutions of general relativity can be thought of a fibered space where the value of $\Psi_2$ at $i_o$ plays the role of the base space. We also show that the restriction of the available symplectic form to each ``fiber'' is degenerate. By finding the orbit manifold of this degenerate direction we obtain the reduced phase space for the radiation data. This reduced phase space posses a global structure, i.e., it does not distinguishes between future or past null infinity. Thus, it can be used as the space of quantum gravitons. Moreover, a Hilbert space can be constructed on each ``fiber'' if an appropriate definition of scalar product is provided. Since there is no natural correspondence between the Hilbert spaces of different foliations they define superselection sectors on the space of asymptotic quantum states.Comment: 22 pages, revtex fil

The jesuits and the indigenous slavery : a debate over voluntary slavery in Brazilian colonial period

In 1566, a new legislation over slavery in Brazil motivated a debate between two members of the Jesuit order: Quirício Caxa and Manuel da Nóbrega over the conditions and limits of indigenous slavery. According to Caxa, a man could sell his children or himself in cases of great necessity whereas for Nóbrega this kind of sales could only happen in cases of extreme necessity. The aim of this paper is to shed light on this debate calling attention to some details not suficiently examined by the more recent studies.Em 1566, uma nova legislação sobre a escravidão no Brasil motivou um debate entre dois membros da Ordem Jesuíta, a saber, Quirício Caxa e Manuel da Nóbrega acerca das condições e dos limites da escravidão indígena. De acordo com Caxa, um homem poderia vender os seus fi lhos ou a si mesmo em casos de grande necessidade, ao passo que para Nóbrega esse tipo de venda poderia ocorrer somente em casos de extrema necessidade. O objetivo deste estudo é lançar luz sobre o debate, chamando atenção para alguns detalhes que não foram examinados sufi cientemente pelos estudos mais recentes

Apostolic Succession in the Writings of Yves Congar and Oscar Cullmann

Since its first explicit enunciation by the end of the second century, apostolic succession has been considered as one of the basic components of the church\u27s apostolicity. As history shows, however, there have been different views on the nature and function of apostolic succession. Moreover, its legitimacy and normativeness have been challenged, particularly since the sixteenth century onwards. In our century, fairly established confessional positions have been reexamined in the light of new theological perspectives, as is evident in the documents produced by the ecumenical movement. The purpose of this research was to set forth, analyze, compare, and evaluate Yves Congar\u27s and Oscar Cullmann\u27s views on apostolic succession. To attain this goal their convictions were considered in the context of their doctrine of the church, and, whenever relevant, from the perspective of their overall theological systems, without neglecting the presuppositions undergirding these authors\u27 ideas and the methodologies used to support them. After a concise overview of apostolic succession throughout history, the dissertation focuses on Yves Congar\u27s position regarding the apostolicity of the church, including apostolicity of ministry and apostolicity of doctrine. Besides his views on Christian history, it includes Congar\u27s view of the bishop of Rome as successor of Peter and his understanding of tradition as the content of apostolic succession. The study also describes and analyzes Oscar Cullmann\u27s view of the uniqueness of the apostles within the framework of salvation history and his categorical denial of apostolic succession. Attention is given to Cullmann\u27s influential study on the role of Peter in the early church, as well as his analysis of the relationship between tradition, the apostles, and Scripture. Finally, the dissertation compares and evaluates the inner consistency, the use of sources, and the relative strengths and weaknesses of Congar\u27s and Cullmann\u27s positions from the point of view of their theological systems, their methodologies and presuppositions, and in the light of scriptural statements relevant for the issue of apostolic succession