Properties of Foreign Exchange Risk Premiums

We study the properties of foreign exchange risk premiums that can explain the forward bias puzzle, de¯ned as the tendency of high-interest rate currencies to ap- preciate rather than depreciate. These risk premiums arise endogenously from the no-arbitrage condition relating the term structure of interest rates and exchange rates. Estimating a±ne (multi-currency) term structure models reveals a noticeable tradeo® between matching depreciation rates and accuracy in pricing bonds. Risk premiums implied by our global a±ne model generate unbiased predictions for cur- rency excess returns and are closely related to global risk aversion, the business cycle, and traditional exchange rate fundamentals

Challenges to providing HIV prevention education to youth with disabilities in South Africa

Purpose: In South Africa, little is known how HIV prevention education is implemented in schools for learners with disabilities. This article reports on findings from a study exploring the extent to which HIV education is reached to people with disabilities in South Africa, and the challenges faced by educators providing HIV prevention education to learners with disabilities. Method: A survey questionnaire completed by 34 schools for learners with special education needs in the Western Cape province of South Africa. Additional complimentary data were collected through interviews with a total of 21 members of staff at schools for learners with disabilities. Results: Respondents recognise the importance of providing HIV prevention education for people with disabilities. Staff reports some challenges in providing HIV prevention education: barriers to communication; discomfort about issues of sexuality and disability; disagreements among staff about what is appropriate content for sexual health education; and fears of promoting sexual activity. Conclusions: There is a need for HIV prevention education to be specifically customized to the needs of the specific population. A general programme, which is included as part of a general curriculum and generally tailored to “mainstream” schools, would need to be adapted according to specific needs and disabling barriers faced

Mutation of Tyrosine Sites in the Human Alpha-Synuclein Gene Induces Neurotoxicity in Transgenic Mice with Soluble Alpha-Synuclein Oligomer Formation

Overexpression of α-synuclein with tyrosine mutated to phenylalanine at position 125 leads to a severe phenotype with motor impairment and neuropathology in Drosophila. Here, we hypothesized that tyrosine mutations would similarly lead to impaired motor performance with neuropathology in a rodent model. In transgenic mice (ASO), tyrosines at positions 125, 133, and 136 in human α-synuclein were mutated to phenylalanine and cloned into a Thy1.2 expression vector, which was used to create transgenic mouse lines on a mixed genetic background TgN(Thy-1-SNCA-YF)4Emfu (YF). The YF mice had a decreased lifespan and displayed a dramatic motor phenotype with paralysis of both hind- and forelegs. Post-translational modification of α-synuclein due to phosphorylation of serine 129 is often seen in inclusions in the brains of patients with α-synucleinopathies. We observed a slight but significant increase in phosphorylation of serine 129 in the cytosol in YF mice compared to age-matched human α-synuclein transgenic mice (ASO). Conversely, significantly decreased phosphorylation of serine 129 was seen in synaptosomes of YF mice that also contained higher amounts of soluble oligomers. YF mice deposited full-length α-synuclein aggregates in neurons widespread in the CNS with the main occurrence in the forebrain structures of the cerebral cortex, the basal ganglia, and limbic structures. Full-length α-synuclein labeling was also prominent in many nuclear regions of the brain stem, deep cerebellar nuclei, and cerebellar cortex. The study shows that the substitution of tyrosines to phenylalanine in α-synuclein at positions 125, 133, and 136 leads to severe toxicity in vivo. An insignificant change upon tyrosine substitution suggests that the phosphorylation of serine 129 is not the cause of the toxicity

FAS-dependent cell death in α-synuclein transgenic oligodendrocyte models of multiple system atrophy

Multiple system atrophy is a parkinsonian neurodegenerative disorder. It is cytopathologically characterized by accumulation of the protein p25α in cell bodies of oligodendrocytes followed by accumulation of aggregated α-synuclein in so-called glial cytoplasmic inclusions. p25α is a stimulator of α-synuclein aggregation, and coexpression of α-synuclein and p25α in the oligodendroglial OLN-t40-AS cell line causes α-synuclein aggregate-dependent toxicity. In this study, we investigated whether the FAS system is involved in α-synuclein aggregate dependent degeneration in oligodendrocytes and may play a role in multiple system atrophy. Using rat oligodendroglial OLN-t40-AS cells we demonstrate that the cytotoxicity caused by coexpressing α-synuclein and p25α relies on stimulation of the death domain receptor FAS and caspase-8 activation. Using primary oligodendrocytes derived from PLP-α-synuclein transgenic mice we demonstrate that they exist in a sensitized state expressing pro-apoptotic FAS receptor, which makes them sensitive to FAS ligand-mediated apoptosis. Immunoblot analysis shows an increase in FAS in brain extracts from multiple system atrophy cases. Immunohistochemical analysis demonstrated enhanced FAS expression in multiple system atrophy brains notably in oligodendrocytes harboring the earliest stages of glial cytoplasmic inclusion formation. Oligodendroglial FAS expression is an early hallmark of oligodendroglial pathology in multiple system atrophy that mechanistically may be coupled to α-synuclein dependent degeneration and thus represent a potential target for protective intervention

Withdrawn, strong, kind, but de-gendered: Non-disabled South Africans’ stereotypes concerning persons with physical disabilities

The present paper examines stereotyping in relation to physical disability and gender in the South Africa. Cross-sectional data for the present study were gathered using free response items in a large survey (n = 1990) examining the attitudes of people without disability towards different facetsof sexuality and disability. The most prominent stereotypes found in thepresent study were those which characterised PWPD as withdrawn and shy, SuperCrips, or happy, funny, and kind. The findings in the present papersuggest that stereotypes of PWPD are not overwhelmingly de-sexualising, but are undifferentiated by gender

The SAGEX Review on Scattering Amplitudes

This is an introduction to, and invitation to read, a series of review articles on scattering amplitudes in gauge theory, gravity, and superstring theory. Our aim is to provide an overview of the field, from basic aspects to a selection of current (2022) research and developments.Comment: 15 pages, overview articl