Markov Switching Vector Autoregressive Modelling of the Nigerian Stock Price and Oil Price Series

 This article studied the relationship between stock prices and crude oil prices of Nigeria using a Markov switching model. Certain properties of the stock price series and crude oil price series such as breaks and stationarity, which are necessary before choosing a multivariate time series model for this relationship were investigated. Unit root and cointegration structural break tests were used where evidence of breaks exists. In particular, each of the series was found to be a nonlinear and nonstationary series with evidence of a structural break. The results of the unit root and cointegration tests in the presence of structural breaks indicated evidence of I (1) and no cointegration between the series. Consequently, a Markov switching VAR (MSM(2)-VAR(1)) model with two regimes was fitted to the data having established the suitability of the series to regime switching models. The results showed that high volatility regime occurs when the economy was under recession. Furthermore, there exists a positive relationship between stock prices and crude oil prices during the high volatility regime and a negative relationship during the low volatility regime.Keywords: MS-VAR, VAR, Crude oil prices, Stock prices, Markov Switching, Structural break <w:LsdException Locked="false" Priority="50" Name="Grid Table 5 Dark Accent 1

Detection of x-rays from galaxy groups associated with the gravitationally lensed systems PG 1115+080 and B1422+231

Gravitational lenses that produce multiple images of background quasars can be an invaluable cosmological tool. Deriving cosmological parameters, however, requires modeling the potential of the lens itself. It has been estimated that up to a quarter of lensing galaxies are associated with a group or cluster which perturbs the gravitational potential. Detection of X-ray emission from the group or cluster can be used to better model the lens. We report on the first detection in X-rays of the group associated with the lensing system PG 1115+080 and the first X-ray image of the group associated with the system B1422+231. We find a temperature and rest-frame luminosity of 0.8 +/- 0.1 keV and 7 +/- 2 x 10^{42} ergs/s for PG 1115+080 and 1.0 +infty/-0.3 keV and 8 +/- 3 x 10^{42} ergs/s for B1422+231. We compare the spatial and spectral characteristics of the X-ray emission to the properties of the group galaxies, to lens models, and to the general properties of groups at lower redshift.Comment: Accepted for publication in ApJ. 17 pages, 5 figures. Minor changes to tex

OVI, NV and CIV in the Galactic Halo: II. Velocity-Resolved Observations with Hubble and FUSE

We present a survey of NV and OVI (and where available CIV) in the Galactic halo, using data from the Far Ultraviolet Spectroscopic Explorer (FUSE) and the Hubble Space Telescope (HST) along 34 sightlines. These ions are usually produced in nonequilibrium processes such as shocks, evaporative interfaces, or rapidly cooling gas, and thus trace the dynamics of the interstellar medium. Searching for global trends in integrated and velocity-resolved column density ratios, we find large variations in most measures, with some evidence for a systematic trend of higher ionization (lower NV/OVI column density ratio) at larger positive line-of-sight velocities. The slopes of log[N(NV)/N(OVI)] per unit velocity range from -0.015 to +0.005, with a mean of -0.0032+/-0.0022(r)+/-0.0014(sys) dex/(km/s). We compare this dataset with models of velocity-resolved high-ion signatures of several common physical structures. The dispersion of the ratios, OVI/NV/CIV, supports the growing belief that no single model can account for hot halo gas, and in fact some models predict much stronger trends than are observed. It is important to understand the signatures of different physical structures to interpret specific lines of sight and future global surveys.Comment: ApJ in press 43 pages, 22 fig

Deciduous enamel 3D microwear texture analysis as an indicator of childhood diet in medieval Canterbury, England

This study conducted the first three dimensional microwear texture analysis of human deciduous teeth to reconstruct the physical properties of medieval childhood diet (age 1-8yrs) at St Gregory's Priory and Cemetery (11th to 16th century AD) in Canterbury, England. Occlusal texture complexity surfaces of maxillary molars from juvenile skeletons (n=44) were examined to assess dietary hardness. Anisotropy values were calculated to reconstruct dietary toughness, as well as jaw movements during chewing. Evidence of weaning was sought, and variation in the physical properties of food was assessed against age and socio-economic status. Results indicate that weaning had already commenced in the youngest children. Diet became tougher from four years of age, and harder from age six. Variation in microwear texture surfaces was related to historical textual evidence that refers to lifestyle developments for these age groups. Diet did not vary with socio-economic status, which differs to previously reported patterns for adults. We conclude, microwear texture analyses can provide a non-destructive tool for revealing subtle aspects of childhood diet in the past

New high-technology products for the treatment of haemophilia

This review will focus on new technologies in development that promise to lead to further advances in haemophilia therapeutics. There has been continued interest in the bioengineering of recombinant factor VIII (rFVIII) and factor IX (rFIX) with improved function to overcome some of the limitations in current treatment, the high costs of therapy and to increase availability to a broader world haemophilia population. Bioengineered forms of rFVIII, rFIX or alternative haemostatic molecules may ultimately have an impact on improving the efficacy of therapeutic strategies for the haemophilias by improving biosynthesis and secretion, functional activity, half-life and immunogenicity. Preventing and suppressing inhibitors to factor (F) VIII remain a challenge for both clinicians and scientists. Recent experiments have shown that it is possible to obtain anti-idiotypic antibodies with a number of desirable properties: (i) strong binding avidity to FVIII inhibitors; (ii) neutralization of inhibitory activity both in vitro and in vivo ; (iii) cross-reactivity with antibodies from unrelated patients, and (iv) no interference with FVIII function. An alternative, although complementary approach, makes use of peptides derived from filamentous-phage random libraries. Mimotopes of FVIII can be obtained, which bind to the paratope of inhibitory activity and neutralize their activity both in vitro and in vivo . In this paper, we review advanced genetic strategies for haemophilia therapy. Until recently the traditional concept for gene transfer of inherited and acquired haematological diseases has been focused on how best to obtain stable insertion of a cDNA into a target-cell genome, allowing expression of a therapeutic protein. However, as gene-transfer vector systems continue to improve, the requirement for regulated gene transcription and hence regulated protein expression will become more critical. Inappropriate protein expression levels or expression of transferred cDNAs in non-intended cell types or tissues may lead to target-cell toxicity or activation of unwanted host immune responses. Regulated protein expression requires that the transferred gene be transferred with its own regulatory cassette that allows for gene transcription and translation approaching that of the normal gene in its endogenous context. New molecular techniques, in particular the use of RNA molecules, now allow for transcription of corrective genes that mimic the normal state.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75577/1/j.1365-2516.2004.00996.x.pd