Signal conditioner circuit for photomultiplier tube

Miniaturized circuit improves measurement of radiation dose absorbed in a scintillation crystal. The temperature coefficient of the field-effect transistor gate-source voltage in the isolation amplifier can be readily controlled

Digital numerically controlled oscillator

The frequency and phase of an output signal from an oscillator circuit are controlled with accuracy by a digital input word. Positive and negative alterations in output frequency are both provided for by translating all values of input words so that they are positive. The oscillator reference frequency is corrected only in one direction, by adding phase to the output frequency of the oscillator. The input control word is translated to a single algebraic sign and the digital 1 is added thereto. The translated input control word is then accumulated. A reference clock signal having a frequency at an integer multiple of the desired frequency of the output signal is generated. The accumulated control word is then compared with a threshold level. The output signal is adjusted in a single direction by dividing the frequency of the reference clock signal by a first integer or by an integer different from the first integer

Modeling, simulation, and control of an extraterrestrial oxygen production plant

The immediate objective is the development of a new methodology for simulation of process plants used to produce oxygen and/or other useful materials from local planetary resources. Computer communication, artificial intelligence, smart sensors, and distributed control algorithms are being developed and implemented so that the simulation or an actual plant can be controlled from a remote location. The ultimate result of this research will provide the capability for teleoperation of such process plants which may be located on Mars, Luna, an asteroid, or other objects in space. A very useful near-term result will be the creation of an interactive design tool, which can be used to create and optimize the process/plant design and the control strategy. This will also provide a vivid, graphic demonstration mechanism to convey the results of other researchers to the sponsor

Causality in real-time dynamic substructure testing

Causality, in the bond graph sense, is shown to provide a conceptual framework for the design of real-time dynamic substructure testing experiments. In particular, known stability problems with split-inertia substructured systems are reinterpreted as causality issues within the new conceptual framework. As an example, causality analysis is used to provide a practical solution to a split-inertia substructuring problem and the solution is experimentally verified

Magnetic variability in the young solar analog KIC 10644253: Observations from the Kepler satellite and the HERMES spectrograph

The continuous photometric observations collected by the Kepler satellite over 4 years provide a whelm of data with an unequalled quantity and quality for the study of stellar evolution of more than 200000 stars. Moreover, the length of the dataset provide a unique source of information to detect magnetic activity and associated temporal variability in the acoustic oscillations. In this regards, the Kepler mission was awaited with great expectation. The search for the signature of magnetic activity variability in solar-like pulsations still remained unfruitful more than 2 years after the end of the nominal mission. Here, however, we report the discovery of temporal variability in the low-degree acoustic frequencies of the young (1 Gyr-old) solar analog KIC 10644253 with a modulation of about 1.5 years with significant temporal variations along the duration of the Kepler observations. The variations are in agreement with the derived photometric activity. The frequency shifts extracted for KIC 10644253 are shown to result from the same physical mechanisms involved in the inner sub-surface layers as in the Sun. In parallel, a detailed spectroscopic analysis of KIC 10644253 is performed based on complementary ground-based, high-resolution observations collected by the HERMES instrument mounted on the MERCATOR telescope. Its lithium abundance and chromospheric activity S-index confirm that KIC 10644253 is a young and more active star than the Sun.Comment: Accepted for publication in A&A, 12 pages, 8 figure

Évolution des cancers de l’œsophage : impact de la stratégie thérapeutique

PURPOSE: To assess the outcome of esophageal cancer according to therapeutic strategy. PATIENTS AND METHODS: One-hundred and twenty patients with esophageal cancer treated by an association of radiotherapy and chemotherapy and possibly surgery, between 2004 and 2010, were retrospectively studied. The first site of relapse was classified as follows: local (tumour), locoregional (tumour and/or nodal: celiac, mediastinal, sus-clavicular) or metastatic. RESULTS: With a 15.7-months (1.4-62) median follow-up, there were 89 deaths and 79 recurrences. Three types of treatments were performed: 50Gy exclusive chemoradiotherapy (47 patients) or 50 to 65Gy exclusive chemoradiotherapy (44 patients) or chemoradiotherapy followed by surgery (27 patients). The local first relapse was as much frequent as distant relapse (50 patients). With a-5cm margin up and down to the tumour, there was only one nodal relapse. Two-year survival was 39.5% (95% confidence interval [IC]: 30.5-40.8) and relapse-free survival was 26.5% (CI: 18.6-35). Multivariate analysis revealed that treatment type and disease stage had a significant impact on survival, relapse-free survival and locoregional control. Compared to exclusive chemoradiotherapy, surgery improved locoregional control (40.2 versus 8.7 months, P=0.0004) but in a younger population. Despite postoperative mortality, the gain was maintained for distance relapse-free survival (40.2 versus 10 months, P=0.0147) and overall survival (29.3 versus 14.2 months, P=0.0088). Compared to 50Gy chemoradiotherapy, local control was improved if high dose chemoradiotherapy was performed (13.8 versus 7.5 months, P=0.05) but not overall survival (14.0 versus 15.4 months, P=0.24). CONCLUSION: More than one-third relapse is local. Locoregional control is better with high dose chemoradiotherapy. In this study, surgery performed in selected patients only, improved locoregional control, relapse-free disease and overall survival

SURFATM-NH3: a model combining the surface energy balance and bi-directional exchanges of ammonia applied at the field scale

A new biophysical model SURFATM-NH3, simulating the ammonia (NH<sub>3</sub>) exchange between terrestrial ecosystems and the atmosphere is presented. SURFATM-NH3 consists of two coupled models: (i) an energy budget model and (ii) a pollutant exchange model, which distinguish the soil and plant exchange processes. The model describes the exchanges in terms of adsorption to leaf cuticles and bi-directional transport through leaf stomata and soil. The results of the model are compared with the flux measurements over grassland during the GRAMINAE Integrated Experiment at Braunschweig, Germany. The dataset of GRAMINAE allows the model to be tested in various meteorological and agronomic conditions: prior to cutting, after cutting and then after the application of mineral fertilizer. The whole comparison shows close agreement between model and measurements for energy budget and ammonia fluxes. The major controls on the ground and plant emission potential are the physicochemical parameters for liquid-gas exchanges which are integrated in the compensation points for live leaves, litter and the soil surface. Modelled fluxes are highly sensitive to soil and plant surface temperatures, highlighting the importance of accurate estimates of these terms. The model suggests that the net flux depends not only on the foliar (stomatal) compensation point but also that of leaf litter. SURFATM-NH3 represents a comprehensive approach to studying pollutant exchanges and its link with plant and soil functioning. It also provides a simplified generalised approach (SVAT model) applicable for atmospheric transport models

A comparison of methods for the measurement of methane emissions from municipal solid waste landfills for the purpose of evaluating their contribution to the greenhouse effect

International audienceThis study was funded and co-ordinated by the French Agence de l'Environnement et de la Maitrise de l'Energie (Ademe) in the framework of the French research programme on the evolution of the climate and the atmosphere, with the specific aim of estimating the contribution to the greenhouse effect due to methane emitted by municipal solid waste landfills