The activated torsion oscillation magnetometer

The activated torsion oscillation magnetometer exploits the mechanical resonance of a cantilever beam, driven by the torque exerted on the sample by an ac field applied perpendicularly to the film plane. We describe a model for the cantilever dynamics which leads to the calculation of the cantilever dynamic profile and allows the mechanical sensitivity of the instrument to be expressed in terms of the minimum electronically detectable displacement. We have developed a capacitance detector of small oscillations which is able to detect displacements of the order of 0.1 nm. We show that sensitivities of the order of 0.5(10-11 Am2 can be in principle achieved. We will subsequently describe the main features of the ATOM prototype which we have built and tested, with particular attention to the design solutions which have been adopted in order to reduce the effects of parasitic vibrations due either to acoustic noise, originating from the ac field coil, or to eddy currents in the capacitor electrodes. The instrument is mounted in a continuous flow cryostat and can work in the 4.2-300 K temperature range. Finally, we will show that our experimental set-up has a second mode of operation, named Torsion Induction Magnetometer (TIM).Comment: Invited Talk at the Moscow International Symposium on Magnetism, 2002 to appear in the J. Mag. Mag. Mat Revised versio

Evolving thermal thresholds explain the distribution of temperature sex reversal in an Australian dragon lizard

Aim: Species with temperature-dependent sex determination (TSD) are particularly vulnerable to climate change because a resultant skew in population sex ratio can have severe demographic consequences and increase vulnerability to local extinction. The Australian central bearded dragon (Pogona vitticeps) has a thermosensitive ZZ male/ZW female system of genetic sex determination (GSD). High incubation temperatures cause reversal of the ZZ genotype to a viable female phenotype. Nest temperatures in the wild are predicted to vary on a scale likely to produce heterogeneity in the occurrence of sex reversal, and so we predict that sex reversal will correlate positively with inferred incubation conditions. Location: Mainland Australia. Methods: Wild-caught specimens of P. vitticeps vouchered in museum collections and collected during targeted field trips were genotypically and phenotypically sexed to determine the distribution of sex reversal across the species range. To determine whether environmental conditions or genetic structure can explain this distribution, we infer the incubation conditions experienced by each individual and apply a multi-model inference approach to determine which conditions associate with sex reversal. Further, we conduct reduced representation sequencing on a subset of specimens to characterize the population structure of this broadly distributed species. Results: Here we show that sex reversal in this widespread Australian dragon lizard is spatially restricted to the eastern part of the species range. Neither climatic variables during the inferred incubation period nor geographic population genetic structure explain this disjunct distribution of sex reversal. The main source of genetic variation arose from isolation by distance across the species range. Main conclusions: We propose that local genetic adaptation in the temperature threshold for sex reversal can counteract the sex-reversing influence of high incubation temperatures in P. vitticeps. Our study demonstrates that complex evolutionary processes need to be incorporated into modelling biological responses to future climate scenarios

A warming climate will make Australian soil a net emitter of atmospheric CO2

Understanding the change in soil organic carbon (C) stock in a warmer climate and the effect of current land management on that stock is critical for soil and environmental conservation and climate policy. By simulation modeling, we predicted changes in Australia’s soil organic C stock from 2010 to 2100. These vary from losses of 0.014–0.077 t C ha−1 year−1 between 2020 and 2045 and 0.013–0.047 t C ha−1 year−1 between 2070 and 2100, under increasing emissions of greenhouse gases and temperature. Thus, Australian soil will be a net emitter of CO2. Depending on the future socio-economic conditions, we predict that croplands will accrue as much as 0.19 t C ha−1 year−1 between 2020 and 2045 due to their management, but accrual will decrease with warming and increased emissions by 2070–2100. The gains will be too small to counteract the losses of C from the larger areas of rangelands and coastal regions that are more sensitive to a warmer climate. In principle, prudent management of the rangelands, for example, improving grazing management and regenerating biodiverse, endemic native plant communities, could sequester more C and mitigate the loss; in practice, it may be more difficult, requiring innovation, interdisciplinary science, cultural awareness and effective policie

Electric field effect on the luminescence of KI:Tl

Thermoluminescence of KI:Tl, x- or &#946;-irradiated at T<77°K showed 2 main peaks at 105 and 170°K. They are resp. attributed to the recombination of mobile VK centers with Tl0 centers and to the recombination of thermally released electrons from Tl0 centers with Tl2+ centres. Similar experiments performed under static electric fields (E<40 kV cm-1) show that the intensity of the 2nd glow peak is strongly reduced. The relative intensity variation is anticorrelated with the intensity of glow peaks occurring at >230°K. We suggestthat in the temperature range in which Tl0 centres are thermally ionised, the effect of the electric field favour the retrapping of these electrons on other traps (still unknown). Irradiation doses also play an important role and their effects are studied at 77°K and T=200°K

Determinants of new drugs prescription in the Swiss healthcare market.

Drug markets are very complex and, while many new drugs are registered each year, little is known about what drives the prescription of these new drugs. This study attempts to lift the veil from this important subject by analyzing simultaneously the impact of several variables on the prescription of novelty. Data provided by four Swiss sickness funds were analyzed. These data included information about more than 470,000 insured, notably their drug intake. Outcome variable that captured novelty was the age of the drug prescribed. The overall variance in novelty was partitioned across five levels (substitutable drug market, patient, physician, region, and prescription) and the influence of several variables measured at each of these levels was assessed using a non-hierarchical multilevel model estimated by Bayesian Markov Chain Monte Carlo methods. More than 92% of the variation in novelty was explained at the substitutable drug market-level and at the prescription-level. Newer drugs were prescribed in markets that were costlier, less concentrated, included more insured, provided more drugs and included more active substances. Over-the-counter drugs were on average 12.5 years older while generic drugs were more than 15 years older than non-generics. Regional disparities in terms of age of prescribed drugs could reach 2.8 years. Regulation of the demand has low impact, with little variation explained at the patient-level and physician-level. In contrary, the market structure (e.g. end of patent with generic apparition, concurrence among producers) had a strong contribution to the variation of drugs ages