Carrier induced ferromagnetism in the insulating Mn doped III-V semiconductor InP

Although InP and GaAs have very similar band-structure their magnetic properties appear to drastically differ. Critical temperatures in (In,Mn)P are much smaller than that of (Ga,Mn)As and scale linearly with Mn concentration. This is in contrast to the square root behaviour found in (Ga,Mn)As. Moreover the magnetization curve exhibits an unconventional shape in (In,Mn)P contrasting with the conventional one of well annealed (Ga,Mn)As. By combining several theoretical approaches, the nature of ferromagnetism in Mn doped InP is investigated. It appears that the magnetic properties are essentially controlled by the position of the Mn acceptor level. Our calculations are in excellent agreement with recent measurements for both critical temperatures and magnetizations. The results are only consistent with a Fermi level lying in an impurity band, ruling out the possibility to understand the physical properties of Mn doped InP within the valence band scenario. The quantitative success found here reveals a predictive tool of choice that should open interesting pathways to address magnetic properties in other compoundsComment: 5 pages and 5 figures, accepted for publication in Phys. Rev.

Fluorometric Method to Assess Lipase Inhibition Activity

Obesity and excess weight have become serious health problems in our developed societies today. Increased blood pressure, blood glucose levels and abnormal blood lipids are frequent consequences. Inhibition of digestive enzymes by pharmacological or nutritional intervention are one avenue to be considered to treat this population. In the present study a robust assay to screen biologically active materials for their ability to inhibit pancreatic lipase, the most important enzyme in fat digestion, has been developed. Methyl-umbelliferyl butyrate was used as an artificial substrate, enabling assessment of lipase activity via specific fluorescence emission. Applicability of the assay was shown by assessment of lipase inhibition activity of wild plants from Switzerland and France. Testing showed some plants to have a high inhibition rate of about 70%. In further projects, this lipase inhibition assay could be used for a scientific proof of biological activity of raw materials with the intention to develop functional foods for weight reduction

Flux Qubits with Long Coherence Times for Hybrid Quantum Circuits

We present measurements of superconducting flux qubits embedded in a three dimensional copper cavity. The qubits are fabricated on a sapphire substrate and are measured by coupling them inductively to an on-chip superconducting resonator located in the middle of the cavity. At their flux-insensitive point, all measured qubits reach an intrinsic energy relaxation time in the 6-20 microseconds range and a pure dephasing time comprised between 3 and 10 microseconds. This significant improvement over previous works opens the way to the coherent coupling of a flux-qubit to individual spins

Influence of a pulsed laser regime on surface finish induced by thedirect metal deposition process on a Ti64 alloy

tThe direct metal deposition (DMD) laser technique is a free-form metal deposition process, which allowsgenerating a prototype or small series of near net-shape structures. Despite numerous advantages, oneof the most critical issues of the technique is that produced pieces have a deleterious surface finish whichrequires post machining steps. Following recent investigations where the use of laser pulses instead of acontinuous regime was successful to obtain smoother DMD structures, this paper relates investigationson the influence of a pulsed laser regime on the surface finish induced by DMD on a widely used titaniumalloy (Ti64). Findings confirm that using high mean powers improves surface finish but also indicate aspecific effect of the laser operating mode: using a quasi-continuous pulsed mode instead of fully-cw laserheating is an efficient way for surface finish improvement. For similar average powers, the use of a pulsedmode with large duty cycles is clearly shown to provide smoothening effects. The formation of larger andstable melt pools having less pronounced lateral curvatures, and the reduction of thermal gradients andMarangoni flow in the external side of the fusion zone were assumed to be the main reasons for surfacefinish improvement. Additional results indicate that combining the benefits from a pulsed regime and auniform laser irradiation does not provide further reduction of surface roughness

EvaSylv: A user-friendly software to evaluate forestry scenarii including natural risk

Forest management relies on the evaluation of silviculture practices. The increase in natural risk due to climate change makes it necessary to consider evaluation criteria that take natural risk into account. Risk integration in existing software requires advanced programming skills.We propose a user-friendly software to simulate even-aged and monospecific forest at the stand level, in order to evaluate and optimize forest management. The software gives the possibility to run management scenarii with or without considering the impact of natural risk. The control variables are the dates and rates of thinning and the cutting age.The risk model is based on a Poisson processus. The Faustmann approach, including tree damage risk, is used to evaluate future benefits, economic or ecosystem services. It relies on the calculation of expected values, for which a dedicated mathematical development has been done. The optimized criteria used to evaluate the various scenarii are the Faustmann value and the Averaged yield value.We illustrate the approach and the software on two case studies: economic optimization of a beech stand and carbon sequestration optimization of a pine stand.Software interface makes it easy for users to write their own (growth-tree damage-economic) models without advanced programming skills. The possibility to run management scenarii with/without considering the impact of natural risk may contribute improving silviculture guidelines and adapting them to climate change. We propose future lines of research and improvement