Abstract The purpose of this paper is to research the countries' exchange rates. The paper is organized around the empirical modeling method which is devised by Van Dijk, D.; Terӓsvirta, T.; Franses, P.H.(2002) and Van Dijk, D.; Terӓsvirta, T.; González, A.(2005). It consists of estimation, specification tests, and forecast stages. The data is chosen from 1974M1 to 2008M12. We set the data from 1974M1 to 2003M12 as in-sample period, and from 2003M1 to 2008M12 as out-of-sample period. The macroeconomic variables considered in this paper include nominal exchange rates and real exchange rates. We get four important empirical results in this paper. First, the STAR model shows that every countries exists ¡§eleventh month effects¡¨. Second, the coefficient of nonlinear in Denmark¡¦s, France¡¦s, Germany¡¦s, Italy¡¦s, Spain¡¦s and UK¡¦s model are statistically significant. This result implies that the government of Japan had been intervening significantly in foreign exchange markets. And the government of other countries had been not intervening in foreign exchange markets. Third, the gamma value of the Panel model is statistically significant but slight. We can conclude that nominal exchange rates and real exchange rates exist relationship in long terms but not in short terms. Fourth, the forecast abilities of two models are almost better than random walk model.

A graph is called star extremal if its fractional chromatic number is equal to its circular chromatic number. Given integers n,k,k' such that 1<=k<=k'<=n/2,the circulant graph G(n,S_k,k') has vertex set [n]={0,1,2,...,n-1} in which i~j if k<=|i-j|<=k' or n-k'<= |i-j|<=n-k. It was known that for n=q(k+k')+r,where 0<=r <k+k', if k'>=5/4k,then G(n,S_k,k') is star extremal. In the thesis, we prove that if k'>=7/6k and q>=4, then G(n,S_k,k') is star extremal.

Thesis (M.S. in Astronautical Engineering)--Naval Postgraduate School, June 2004. / Thesis advisor(s): Brij Agrawal, Marcello Romano. Includes bibliographical references (p. 101-102). Also available online.

There is no abstract available for this dissertation.

It has become increasingly clear that many binary systems will pass through a common envelope stage at some point during their evolution. For short period systems composed of main-sequence 0 and early B stars this stage will probably occur for the first time towards the end of hydrogen-core burning in the primary component (case A evolution) rather than during the transition to the giant stage (case B evolution). If masses, radii, luminosities, temperatures and orbital parameters were well determined for a good sample of those systems, it could be established whether the individual components were so close that case A evolution was inevitable or whether the primary component had enough room to complete its main-sequence phase before reaching its Roche. limit and hence case B evolution. The latter mode has been studied extensively (both conservatively and non-conservatively) whereas the reception of matter by the secondary component in the rapid mass-transfer phase of case A evolution has only very recently been investigated. It is still one of the principal problems impeding further progress on this scenario. To resolve this situation and provide observational material with which to compare these theoretical models, an observing program was established to study systems of spectral type earlier than B5 and of orbital period of less than 1.8 in both the Northern and Southern Hemispheres. Light curves were obtained at St Andrews using the newly-refurbished Twin Photometric Telescope and analysed using software developed specifically for this instrument. Further spectroscopic and photometric data were obtained at La Palma SAAO, Sierra Nevada and Boyden. Analyses of these spectroscopic and photometric observations have provided the necessary physical parameters to determine the evolutionary status of these systems. The systems observed were AH Cephei and V1182 Aquilae which are shown to be detached systems, TT Aurigae, SX Aurigae and AI Crucis which are all semi-detached systems and V701 Scorpii and HZ Pyxidis which are contact systems. Accurately-determined parameters of 14 stars have been found, including four 0 stars in detached systems. Therefore-the number of stars with well-determined masses of greater than 30M has been increased by 25%. It is clear from this study that case A mass transfer will play and has played an important role in the evolution of five out of the seven systems. It is debatable whether or not the contact systems have passed through a mass transfer phase, particularly RZ Pyx. The evolutionary history of this system is of particular interest, especially if this binary was in a marginal contact configuration when it arrived on the main sequence. Attempts have been made to look for intrinsic variability in these systems but no periodic variation has been found in any of them. If such a phenomenon exists in one of the components of the binaries in the sample then it must have an amplitude of less than 0.01. The comparison of the physical parameters of 67 stars compiled by the author from this work and from published data with theoretical zero-age and terminal-age main sequences shows that traditional modelling of semi-convection without mass loss is not adequate. Convective overshooting and mass loss play a very important role in the evolution of massive close binary systems of short period.

In this work a review of many of the current theories of star formation as it is understood today is presented. New polarimetric observations of three cometary nebulae, RMon/NGC2261, RCr A/NGC6729 and the Chamaeleon Infrared Nebula are presented and discussed. It is shown how previous polarimetric measurements of the illuminating source of Hubble's variable nebula (NGC2261) have often produced results which increase in error with increasing wavelength. The reason for this is that previous authors have used an aperture size for measurements of R Mon which includes effects of a highly polarized feature ~ 5" north of RMon. Though this phenomenon has been seen before by other observers, its effect on polarimetric measurements of R Mon has not been recognised before despite tests to check for this. The data presented here agree with the interpretation that this feature is the northern-lobe of a mini-bipolar nebula, and it is further suggested that this is a manifestation of episodic mass outflow from R Mon. Previous explanations for the polarization of R Mon and RCr A cannot explain the rapid change in polarization and position angle that these young stellar objects are seen to undergo. Models of these objects which assume that they appear as polarized sources are used to explain the polarizations and are discussed. These models are not only able to produce the level of polarization seen at the source, but they are also currently the best models for explaining the rapid changes in polarization that are observed. A jet-like feature is seen to the south-west of the main nebulosity in the Chamaeleon IRN for the first time in observations presented in this thesis. A similar jet seen emerging from RCr A has been explained as being an emission feature collimated by an inner-circumstellar disc by previous authors. Evidence presented in this work for the jets seen emanating from both RCr A and the Chamaeleon IRN, suggests that these features are merely the preferentially illuminated rims of one of the outflow cavities, seen mainly by reflection of light from the source. Further evidence is provided to show that NGC2261 and NGC6729 are illuminated by RMon and RCr A respectively. In the case of the Chamaeleon IRN new evidence is provided to show that the nebula is illuminated by a heavily obscured infrared source located midway between the two outflow cavities.

No description available.

No description available.

Zugl.: Saarbrücken, Universiẗat, Diss., 2006. / Hergestellt on demand.

Ulm, Univ., Diss., 2008.