Robust Tests of Forward Exchange Market Efficiency with Empirical Evidence from the 1920’s

This paper provides a robust statistical approach to testing the unbiasedness hypothesis in forward exchange market efficiency studies. The methods we use allow us to work explicitly with levels rather than differenced data. They are statistically robust to data distributions with heavy tails, and they can be applied to data sets where the frequency of observation and the futures maturity do not coincide. In addition, our methods allow for stochastic trend nonstationarity and general forms of serial dependence. The methods are applied to daily data of spot exchange rates and forward exchange rates during the 1920’s, which marked the first episode of a broadly general floating exchange rate system. The tail behavior of the data is analyzed using an adaptive data-based method for estimating the tail slope of the density. The results confirm the need for the use of robust regression methods. We find cointegration between the forward rate and spot rate for the four currencies we consider (the Belgian and French francs, the Italian lira and the US dollar, all measured against the British pound), we find support for a stationary risk premium in the case of the Belgian franc, the Italian lira and the US dollar, and we find support for the simple market efficiency hypothesis (where the forward rate is an unbiased predictor of the future spot rate and there is a zero mean risk premium) in the case of the US dollar

Gene expression by marrow stromal cells in a porous collagen-glycosaminoglycan scaffold is affected by pore size and mechanical stimulation.

Marrow stromal cell (MSC) populations, which are a potential source of undifferentiated mesenchymal cells, and culture scaffolds that mimic natural extracellular matrix are attractive options for orthopaedic tissue engineering. A type I collagen-glycosaminoglycan (CG) scaffold that has previously been used clinically for skin regeneration was recently shown to support expression of bone-associated proteins and mineralisation by MSCs cultured in the presence of osteogenic supplements. Here we follow RNA markers of osteogenic differentiation in this scaffold. We demonstrate that transcripts of the late stage markers bone sialoprotein and osteocalcin are present at higher levels in scaffold constructs than in two-dimensional culture, and that considerable gene induction can occur in this scaffold even in the absence of soluble osteogenic supplements. We also find that bone-related gene expression is affected by pore size, mechanical constraint, and uniaxial cyclic strain of the CG scaffold. The data presented here further establish the CG scaffold as a potentially valuable substrate for orthopaedic tissue engineering and for research on the mechanical interactions between cells and their environment, and suggest that a more freely-contracting scaffold with larger pore size may provide an environment more conducive to osteogenesis than constrained scaffolds with smaller pore sizes

Sex, body size, and boldness shape the seasonal foraging habitat selection in southern elephant seals

Selecting foraging habitat is a fundamental behavior in the life of organisms as it directly links resource acquisition to fitness. Differences in habitat selection among individuals may arise from several intrinsic and extrinsic factors, and yet, their interaction has been given little attention in the study of wild populations. We combine sex, body size, and boldness to explain individual differences in the seasonal foraging habitat selection of southern elephant seals (Mirounga leonina) from the Kerguelen Archipelago. We hypothesize that habitat selection is linked to the trade‐off between resource acquisition and risk, and that individuals differ in their position along this trade‐off because of differences in reproductive strategies, life stages, and metabolic requirements. Before the post‐molt foraging trip, we used a novel object approach test to quantify the boldness of 28 subadult and adult females and 42 subadult males and equipped them with data loggers to track their movements at sea. Subadult males selected neritic and oceanic habitats, whereas females mostly selected less productive oceanic habitats. Both sexes showed a seasonal shift from Antarctic habitats in the south in the summer to the free of ice subantarctic and subtropical habitats in the north in the winter. Males avoided oceanic habitats and selected more productive neritic and Antarctic habitats with body size mostly in the winter. Bolder males selected northern warmer waters in winter, while shyer ones selected the Kerguelen plateau and southern colder oceanic waters. Bolder females selected the Kerguelen plateau in the summer when prey profitability is assumed to be the highest. This study not only provides new insights into the spatiotemporal foraging ecology of elephant seals in relation to personality but also emphasizes the relevance of combining several intrinsic and extrinsic factors in understanding among‐individual variation in space use essential in wildlife management and conservation

The Fungicide Chlorothalonil Is Nonlinearly Associated with Corticosterone Levels, Immunity, and Mortality in Amphibians

Background: Contaminants have been implicated in declines of amphibians, a taxon with vital systems similar to those of humans. However, many chemicals have not been thoroughly tested on amphibians or do not directly kill them

Neurotrophin gene augmentation by electrotransfer to improve cochlear implant hearing outcomes

This Review outlines the development of DNA-based therapeutics for treatment of hearing loss, and in particular, considers the potential to utilize the properties of recombinant neurotrophins to improve cochlear auditory (spiral ganglion) neuron survival and repair. This potential to reduce spiral ganglion neuron death and indeed re-grow the auditory nerve fibres has been the subject of considerable pre-clinical evaluation over decades with the view of improving the neural interface with cochlear implants. This provides the context for discussion about the development of a novel means of using cochlear implant electrode arrays for gene electrotransfer. Mesenchymal cells which line the cochlear perilymphatic compartment can be selectively transfected with (naked) plasmid DNA using array - based gene electrotransfer, termed ‘close-field electroporation’. This technology is able to drive expression of brain derived neurotrophic factor (BDNF) in the deafened guinea pig model, causing re-growth of the spiral ganglion peripheral neurites towards the mesenchymla cells, and hence into close proximity with cochlear implant electrodes within scala tympani. This was associated with functional enhancement of the cochlear implant neural interface (lower neural recruitment thresholds and expanded dynamic range, measured using electrically - evoked auditory brainstem responses). The basis for the efficiency of close-field electroporation arises from the compression of the electric field in proximity to the ganged cochlear implant electrodes. The regions close to the array with highest field strength corresponded closely to the distribution of bioreporter cells (adherent human embryonic kidney (HEK293)) expressing green fluorescent reporter protein (GFP) following gene electrotransfer. The optimization of the gene electrotransfer parameters using this cell-based model correlated closely with in vitro and in vivo cochlear gene delivery outcomes. The migration of the cochlear implant electrode array-based gene electrotransfer platform towards a clinical trial for neurotrophin-based enhancement of cochlear implants is supported by availability of a novel regulatory compliant mini-plasmid DNA backbone (pFAR4; plasmid Free of Antibiotic Resistance v.4) which could be used to package a ‘humanized’ neurotrophin expression cassette. A reporter cassette packaged into pFAR4 produced prominent GFP expression in the guinea pig basal turn perilymphatic scalae. More broadly, close-field gene electrotransfer may lend itself to a spectrum of potential DNA therapeutics applications benefitting from titratable, localised, delivery of naked DNA, for gene augmentation, targeted gene regulation, or gene substitution strategies

The SDSS-III Baryon Oscillation Spectroscopic Survey: Quasar Target Selection for Data Release Nine

The SDSS-III Baryon Oscillation Spectroscopic Survey (BOSS), a five-year spectroscopic survey of 10,000 deg^2, achieved first light in late 2009. One of the key goals of BOSS is to measure the signature of baryon acoustic oscillations in the distribution of Ly-alpha absorption from the spectra of a sample of ~150,000 z>2.2 quasars. Along with measuring the angular diameter distance at z\approx2.5, BOSS will provide the first direct measurement of the expansion rate of the Universe at z > 2. One of the biggest challenges in achieving this goal is an efficient target selection algorithm for quasars over 2.2 < z < 3.5, where their colors overlap those of stars. During the first year of the BOSS survey, quasar target selection methods were developed and tested to meet the requirement of delivering at least 15 quasars deg^-2 in this redshift range, out of 40 targets deg^-2. To achieve these surface densities, the magnitude limit of the quasar targets was set at g <= 22.0 or r<=21.85. While detection of the BAO signature in the Ly-alpha absorption in quasar spectra does not require a uniform target selection, many other astrophysical studies do. We therefore defined a uniformly-selected subsample of 20 targets deg^-2, for which the selection efficiency is just over 50%. This "CORE" subsample will be fixed for Years Two through Five of the survey. In this paper we describe the evolution and implementation of the BOSS quasar target selection algorithms during the first two years of BOSS operations. We analyze the spectra obtained during the first year. 11,263 new z>2.2 quasars were spectroscopically confirmed by BOSS. Our current algorithms select an average of 15 z > 2.2 quasars deg^-2 from 40 targets deg^-2 using single-epoch SDSS imaging. Multi-epoch optical data and data at other wavelengths can further improve the efficiency and completeness of BOSS quasar target selection. [Abridged]Comment: 33 pages, 26 figures, 12 tables and a whole bunch of quasars. Submitted to Ap

Comprehensive characterisation of the vascular effects of cisplatin-based chemotherapy in patients with testicular cancer

Background: Cisplatin-based chemotherapy increases the risk of cardiovascular and renal disease. Objectives: We aimed to define the time course, pathophysiology, and approaches to prevent cardiovascular disease associated with cisplatin-based chemotherapy. Methods: Two cohorts of patients with a history of testicular cancer (n = 53) were recruited. Cohort 1 consisted of 27 men undergoing treatment with: 1) surveillance; 2) 1 to 2 cycles of bleomycin, etoposide, and cisplatin (BEP) chemotherapy (low-intensity cisplatin); or 3) 3 to 4 cycles of BEP (high-intensity cisplatin). Endothelial function (percentage flow-mediated dilatation) and cardiovascular biomarkers were assessed at 6 visits over 9 months. Cohort 2 consisted of 26 men previously treated 1 to 7 years ago with surveillance or 3 to 4 cycles BEP. Vasomotor and fibrinolytic responses to bradykinin, acetylcholine, and sodium nitroprusside were evaluated using forearm venous occlusion plethysmography. Results: In cohort 1, the percentage flow-mediated dilatation decreased 24 h after the first cisplatin dose in patients managed with 3 to 4 cycles BEP (10.9 ± 0.9 vs. 16.7 ± 1.6; p &lt; 0.01) but was unchanged from baseline thereafter. Six weeks after starting 3 to 4 cycles BEP, there were increased serum cholesterol levels (7.2 ± 0.5 mmol/l vs. 5.5 ± 0.2 mmol/l; p = 0.01), hemoglobin A1c (41.8 ± 2.0 mmol/l vs. 35.5 ± 1.2 mmol/l; p &lt; 0.001), von Willebrand factor antigen (62.4 ± 5.4 mmol/l vs. 45.2 ± 2.8 mmol/l; p = 0.048) and cystatin C (0.91 ± 0.07 mmol/l vs. 0.65 ± 0.09 mmol/l; p &lt; 0.01). In cohort 2, intra-arterial bradykinin, acetylcholine, and sodium nitroprusside caused dose-dependent vasodilation (p &lt; 0.0001). Vasomotor responses, endogenous fibrinolytic factor release, and cardiovascular biomarkers were not different in patients managed with 3 to 4 cycles of BEP versus surveillance. Conclusions: Cisplatin-based chemotherapy induces acute and transient endothelial dysfunction, dyslipidemia, hyperglycemia, and nephrotoxicity in the early phases of treatment. Cardiovascular and renal protective strategies should target the early perichemotherapy period. (Clinical Characterisation of the Vascular Effects of Cis-platinum Based Chemotherapy in Patients With Testicular Cancer [VECTOR], NCT03557177; Intermediate and Long Term Vascular Effects of Cisplatin in Patients With Testicular Cancer [INTELLECT], NCT03557164

Measurements of Flavour Dependent Fragmentation Functions in Z^0 -> qq(bar) Events

Fragmentation functions for charged particles in Z -> qq(bar) events have been measured for bottom (b), charm (c) and light (uds) quarks as well as for all flavours together. The results are based on data recorded between 1990 and 1995 using the OPAL detector at LEP. Event samples with different flavour compositions were formed using reconstructed D* mesons and secondary vertices. The \xi_p = ln(1/x_E) distributions and the position of their maxima \xi_max are also presented separately for uds, c and b quark events. The fragmentation function for b quarks is significantly softer than for uds quarks.Comment: 29 pages, LaTeX, 5 eps figures (and colour figs) included, submitted to Eur. Phys. J.