Le Puy-en-Velay – Baptistère Saint-Jean

Identifiant de l'opération archéologique : 120 Date de l'opération : 2006 (FP) Le projet collectif de recherche sur le baptistère Saint-Jean groupe cathédral du Puy-en-Velay a été engagé en 2004 à l’initiative du service régional de l’archéologie (BSR 2004, p. 61 ; BSR 2005, p. 65). Cette recherche dont les objectifs sont de déterminer la datation, les différentes phases de construction, la fonction initiale et la place du monument, dont l’usage baptismal n’est attesté qu’à partirdu XIIIe s.,..

Le Puy-en-Velay – Baptistère Saint-Jean

Identifiant de l'opération archéologique : 120 Date de l'opération : 2006 (FP) Le projet collectif de recherche sur le baptistère Saint-Jean groupe cathédral du Puy-en-Velay a été engagé en 2004 à l’initiative du service régional de l’archéologie (BSR 2004, p. 61 ; BSR 2005, p. 65). Cette recherche dont les objectifs sont de déterminer la datation, les différentes phases de construction, la fonction initiale et la place du monument, dont l’usage baptismal n’est attesté qu’à partirdu XIIIe s.,..

Narbonne et le Narbonnais dans l’Antiquité tardive, contribution de l’étude des roches marbrières à la connaissance des œuvres sculptées

The recurring questions about the identification of materials, especially the white marble, have led to the development of a program to identify materials by various analyses (size of the grains, accessory minerals, cathodoluminescence and isotopic analysis) with specific input from them. A systematic investigation concerning white marble artifacts of the Late Antiquity (IVth-VIIIth centuries) in Narbonnais, (South of France) gathered 100 samples, give a better knowledge of the quarries centers, the probable location of execution of works, their dissemination area and the role of the port of Narbonne, in a region in contact with the Mediterranean and Atlantic worlds

Narbonne et le Narbonnais dans l’Antiquité tardive, contribution de l’étude des roches marbrières à la connaissance des œuvres sculptées

The recurring questions about the identification of materials, especially the white marble, have led to the development of a program to identify materials by various analyses (size of the grains, accessory minerals, cathodoluminescence and isotopic analysis) with specific input from them. A systematic investigation concerning white marble artifacts of the Late Antiquity (IVth-VIIIth centuries) in Narbonnais, (South of France) gathered 100 samples, give a better knowledge of the quarries centers, the probable location of execution of works, their dissemination area and the role of the port of Narbonne, in a region in contact with the Mediterranean and Atlantic worlds

Molecular Dynamics Simulation of Chemical Vapor Deposition of Amorphous Carbon: Dependence on H/C Ratio of Source Gas

By molecular dynamics simulation, the chemical vapor deposition of amorphous carbon onto graphite and diamond surfaces was studied. In particular, we investigated the effect of source H/C ratio, which is the ratio of the number of hydrogen atoms to the number of carbon atoms in a source gas, on the deposition process. In the present simulation, the following two source gas conditions were tested: one was that the source gas was injected as isolated carbon and hydrogen atoms, and the other was that the source gas was injected as hydrocarbon molecules. Under the former condition, we found that as the source H/C ratio increases, the deposition rate of carbon atoms decreases exponentially. This exponential decrease in the deposition rate with increasing source H/C ratio agrees with experimental data. However, under the latter molecular source condition, the deposition rate did not decrease exponentially because of a chemical reaction peculiar to the type of hydrocarbon in the source gas.Comment: accepted by Jpn. J. Appl. Phys. (2008

Study of dispersion by NMR: comparison between NMR measurements and stochastic simulation

Dispersion remains, today, a highly topical subject. Our group has been interested in characterizing this phenomenon by pulsed-field-gradient NMR technique. Direct measurement of the dispersion coefficient can be done with a Pulsed Gradient Spin Echo (PGSE) sequence by assuming that the asymptotic regime is reached. In unsteady state, the propagator formalism is used. To better understand these measurements, the NMR experiment is modeled using a stochastic simulation (random walks) and compared with experimental results. The comparison is made for the simple case of Poiseuille flow in a circular tube (Taylor-Aris dispersion)

Study of dispersion by NMR: comparison between NMR measurements and stochastic simulation

Dispersion remains, today, a highly topical subject. Our group has been interested in characterizing this phenomenon by pulsed-field-gradient NMR technique. Direct measurement of the dispersion coefficient can be done with a Pulsed Gradient Spin Echo (PGSE) sequence by assuming that the asymptotic regime is reached. In unsteady state, the propagator formalism is used. To better understand these measurements, the NMR experiment is modeled using a stochastic simulation (random walks) and compared with experimental results. The comparison is made for the simple case of Poiseuille flow in a circular tube (Taylor-Aris dispersion)

Research Needs and Challenges in the FEW System: Coupling Economic Models with Agronomic, Hydrologic, and Bioenergy Models for Sustainable Food, Energy, and Water Systems

On October 12–13, a workshop funded by the National Science Foundation was held at Iowa State University in Ames, Iowa with a goal of identifying research needs related to coupled economic and biophysical models within the FEW system. Approximately 80 people attended the workshop with about half representing the social sciences (primarily economics) and the rest from the physical and natural sciences. The focus and attendees were chosen so that findings would be particularly relevant to SBE research needs while taking into account the critical connectivity needed between social sciences and other disciplines. We have identified several major gaps in existing scientific knowledge that present substantial impediments to understanding the FEW system. We especially recommend research in these areas as a priority for future funding: 1. Economic models of decision-making in coupled systems Deliberate human activity has been the dominant factor driving environmental and land-use changes for hundreds of years. While economists have made great strides in modeling and understanding these choices, the coupled systems modeling literature, with some important exceptions, has not reflected these contributions. Several paths forward seem fruitful. First, baseline economic models that assume rationality can be used much more widely than they are currently. Moreover, the current generation of IAMs that include rational agents have emphasized partial equilibrium studies appropriate for smaller systems. To allow this approach to be used to study larger systems, the potential for (and consequences of) general equilibrium effects should be studied as well. Second, it is important to address shortcomings in these models of economic decision-making. Valuable improvements could be gained from developing coupled models that draw insights from behavioral economics. Many decision-makers deviate systematically from actions that would be predicted by strict rationality, but very few IAMs incorporate this behavior, potentially leading to inaccurate predictions about the effects of policies and regulations. Improved models of human adaptation and induced technological change can also be incorporated into coupled models. Particularly for medium to long-run models, decisions about adaptation and technological change will have substantial effects on the conclusions and policy implications, but more compelling methods for incorporating these changes into modeling are sorely needed. In addition, some economic decisions are intrinsically dynamic yet few coupled models explicitly incorporate dynamic models. Economic models that address uncertainty in decision making are also underutilized in coupled models of the FEW system. 2. Coupling models across disciplines Despite much recent progress, established models for one component of the FEW system often cannot currently produce outcomes that can be used as inputs for models of other components. This misalignment makes integrated modeling difficult and is especially apparent in linking models of natural phenomena with models of economic decision-making. Economic agents typically act to maximize a form of utility or welfare that is not directly linked to physical processes, and they typically require probabilistic forecasts as an input to their decision-making that many models in the natural sciences cannot directly produce. We believe that an especially promising approach is the development of “bridge” models that convert outputs from one model into inputs for another. Such models can be viewed as application-specific, reduced-form distillations of a richer and more realistic underlying model. Ideally, these bridge models would be developed in collaborative research projects involving economists, statisticians, and disciplinary specialists, and would contribute to improved understanding in the scientific discipline as well. 3. Model validation and comparison There is little clarity on how models should be evaluated and compared to each other, both within individual disciplines and as components of larger IAMs. This challenge makes larger integrated modeling exercises extremely difficult. Some potential ways to advance are by developing statistical criteria that measure model performance along the dimensions suitable for inclusion in an IAM as well as infrastructure and procedures to facilitate model comparisons. Focusing on the models’ out-of-sample distributional forecasting performance, as well as that of the IAM overall, is especially promising and of particular importance. Moreover, applications of IAMs tend to estimate the effect of hypothetical future policy actions, but there have been very few studies that have used these models to estimate the effect of past policy actions. These exercises should be encouraged. They offer a well-understood test bed for the IAMs, and also contribute to fundamental scientific knowledge through better understanding of the episode in question. The retrospective nature of this form of analysis also presents the opportunity to combine reduced-form estimation strategies with the IAMs as an additional method of validation