First Results on it p Modes from GOLF Experiment

The GOLF experiment on the SOHO mission aims to study the internal structure of the Sun by measuring the spectrum of global oscillations in the frequency range 10^-7 to 10^-2 Hz. Here we present the results of the analysis of the first 8 months of data. Special emphasis is put into the frequency determination of the p modes, as well as the splitting in the multiplets due to rotation. For both, we show that the improvement in S/N level with respect to the ground-based networks and other experiments is essential in achieving a very low-degree frequency table with small errors ∼ 2 parts in 10^-5). On the other hand, the splitting found seems to favour a solar core which does not rotate slower than its surface. The line widths do agree with theoretical expectations and other observations.     

PheniX: a new vision for the hard X-ray sky

We are proposing a mission devoted to high energy X-ray astronomy that is based on a focusing telescope operating in the 1?C200?keV energy range but optimized for the hard X-ray range. The main scientific topics concern: Physics of compact objects: The proximity of compact objects provides a unique laboratory to study matter and radiation in extreme conditions of temperature and density in strong gravitational environment. The emission of high energy photons from these objects is far from being understood. The unprecedented sensitivity in the high energy domain will allow a precise determination of the non-thermal processes at work in the vicinity of compact objects. The full 1?C200?keV energy coverage will be ideal to disentangle the emission processes produced in the spacetime regions most affected by strong-gravity, as well as the physical links: disk?Cthermal emission?Ciron line?Ccomptonisation?Creflection?Cnon-thermal emission?Cjets. Neutron stars?Cmagnetic field?Ccyclotron lines: Time resolved spectroscopy (and polarimetry) at ultra-high sensitivity of AXP, milliseconds pulsars and magnetars will give new tools to study the role of the synchrotron processes at work in these objects. Cyclotron lines?Cdirect measurement of magnetic filed?Cequation of state constraints?Cshort bursts?Cgiant flares could all be studied with great details. AGN: The large sensitivity improvement will provide detailed spectral properties of the high energy emission of AGN??s. This will give a fresh look to the connection between accretion and jet emission and will provide a new understanding of the physical processes at work. Detection of high-redshift active nuclei in this energy range will allow to introduce an evolutionary aspect to high-energy studies of AGN, probing directly the origin of the Cosmic X-ray Background also in the non-thermal range (> 20?keV). Element formation?CSupernovae: The energy resolution achievable for this mission (<0.5?keV) and a large high energy effective area are ideally suited for the 44Ti line study (68 and 78?keV). This radioactive nuclei emission will give an estimate of their quantities and speed in their environment. In addition the study of the spatial structure and spectral emission of SNR will advance our knowledge of the dynamics of supernovae explosions, of particles acceleration mechanisms and how the elements are released in the interstellar medium. Instrumental design: The progress of X-ray focusing optics techniques allows a major step in the instrumental design: the collecting area becomes independent of the detection area. This drastically reduces the instrumental background and will open a new era. The optics will be based on depth-graded multi-layer mirrors in a Wolter I configuration. To obtain a significant effective area in the hundred of keV range a focal length in the 40?C50 meters range (attainable with a deployable mast) is needed. In addition such a mission could benefit from recent progress made on mirror coating. We propose to cover the 1?C200?keV energy range with a single detector, a double-sided Germanium strip detector operating at 80?K. The main features will be: (a) good energy resolution (.150?keV at 5?keV and <.5?keV at 100?keV), (b) 3 dimensional event localization with a low number of electronic chains, (c) background rejection by the 3D localization, (d) polarisation capabilities in the Compton regime.     

Satellite imaging coral reef resilience at regional scale. A case-study from Saudi Arabia

We propose a framework for spatially estimating a proxy for coral reef resilience using remote sensing. Data spanning large areas of coral reef habitat were obtained using the commercial QuickBird satellite, and freely available imagery (NASA, Google Earth). Principles of coral reef ecology, field observation, and remote observations, were combined to devise mapped indices. These capture important and accessible components of coral reef resilience. Indices are divided between factors known to stress corals, and factors incorporating properties of the reef landscape that resist stress or promote coral growth. The first-basis for a remote sensed resilience index (RSRI), an estimate of expected reef resilience, is proposed. Developed for the Red Sea, the framework of our analysis is flexible and with minimal adaptation, could be extended to other reef regions. We aim to stimulate discussion as to use of remote sensing to do more than simply deliver habitat maps of coral reefs.     

Grain structure of the Earth's inner core

The coarsening rate of an initial grain structure is calculated and compared to the inner core growth rate. An estimate of the present size of the grains in the centre of the core varies from 560 m to 12 km, depending on the value taken for the diffusion coefficient of iron in the core. Regardless of the hypotheses chosen, this size is homogeneous inside the inner core.     

The mark III Nançay radioheliograph The Radioheliograph Group

A north-south array has been added to the Mark II Nançay Radioheliograph (Radioheliograph Group, 1977). This instrument gives at 169 MHz two one-dimensional images of the Sun in the east-west and north-south directions including measurement of the circular polarization ratio. The main performances of this instrument are high space and time resolutions, flexible on line data processing and the possibility of off-line interactive data reduction. The method of calibration is briefly described. A few observations are presented.     

Impact of environmental factors on in situ determination of iron in seawater by flow injection analysis

A sensitive method for iron determination in seawater has been adapted on a submersible chemical analyser for in situ measurements. The technique is based on flow injection analysis (FIA) coupled with spectrophotometric detection. When direct injection of seawater was used, the detection limit was 1.6 nM, and the precision 7%, for a triplicate injection of a 4 nM standard. At low iron concentrations, on line preconcentration using a column filled with 8-hydroxyquinoline (8HQ) resin was used. The detection limit was 0.15 nM (time of preconcentration = 240 s), and the precision 6%, for a triplicate determination of a 1 nM standard, allowing the determination of Fe in most of the oceanic regimes, except the most depleted surface waters. The effect of temperature, pressure, salinity, copper, manganese, and iron speciation on the response of the analyser was investigated. The slope of the calibration curves followed a linear relation as a function of pressure (C_p = 2.8 × 10^{− 5}P + 3.4 × 10^{− 2} s nmol^{− 1}, R² = 0.997, for Θ = 13 °C) and an exponential relation as a function of temperature (C_Θ = 0.009e^0.103Θ, R² = 0.832, for P = 3 bar). No statistical difference at 95% confidence level was observed for samples of different salinities (S = 0, 20, 35). Only very high concentration of copper (1000 × [Fe]) produced a detectable interference. The chemical analyser was deployed in the coastal environment of the Bay of Brest to investigate the effect of iron speciation on the response of the analyser. Direct injection was used and seawater samples were acidified on line for 80 s. Dissolved iron (DFe, filtered seawater (0.4 μm), acidified and stored at pH 1.8) corresponded to 29 ± 4% of Fe_a (unfiltered seawater, acidified in line at pH 1.8 for 80 s). Most of Fe_a (71 ± 4%) was probably a fraction of total dissolvable iron (TDFe, unfiltered seawater, acidified and stored at pH 1.8).     

Gen*: a generic toolkit to generate spatially explicit synthetic populations

Agent-based models tend to integrate more and more data that can deeply impact their outcomes. Among these data, the ones that deal with agent attributes and localization are particularly important, but are very difficult to collect. In order to tackle this issue, we propose a complete generic toolkit called Gen* dedicated to generating spatially explicit synthetic populations from global (census and GIS) data. This article focuses on the localization methods provided by Gen* that are based on regression, geometrical constraints and spatial distributions. The toolkit is applied for a case study concerning the generation of the population of Rouen (France) and shows the capabilities of Gen* regarding population spatialization.     

Climate change,environmental degradation and migration

Climate change will have a progressively increasing impact on environmental degradation and environmentally dependent socio-economic systems with potential to cause substantial population displacement. The key concerns in Less Developed Countries (LDCs) will include serious threats to food security and health, considerable economic decline, inundation of coastal areas, and degradation of land and fresh water resources (Reuveny in Polit Geogr, 2007). The relationship between environmental change and potential humanitarian crises has been captured by: McGregor (Geography and refugees: patterns and processes of change, Belhaven Press, London, pp 159–70, 1993), Kibreab (Environment and Population Change, International Union for the Scientific Study of Population, Liège, 1994), Kibreab (Disasters 21(1):20–38, 1997), Myers (Bioscience 43:752–761, 1993), Myers and Kent (Environmental exodus: an emergent crisis in the global arena, Climate Institute, Washington, DC, 1995), Black (New Issues in Refugee Research, Working Paper no. 34, 2001), Lee (Environmental matters: conflict, refugees and international relations, World Human Development Institute Press, Seoul and Tokyo, 2001), Castles (Environmental Change and Induced Migration: Making Sense of the Debate Working Paper No. 70, 2002), Christian Aid (Human tide: the real migration crisis, Christian Aid, London, 2007), and Massey et al. (, 2007). However, we know little about the interplay between environmental change and stresses on ecological systems, resulting socio-economic vulnerability and potential outcomes in terms of population displacement or induced migration. So far these relationships are poorly conceptualized, lack systematic investigation, and are reduced to simplistic causal explanations. This leads to misleading conclusions that deny the complex multivariate processes—environmental, political, social, and economic— which are the root causes of environmentally induced migration and/or conflict. When people are faced with severe environmental degradation they have one of three options: (1) stay and adapt to mitigate the effects; (2) stay, do nothing and accept a lower quality of life; or (3) leave the affected area. The process of movement and migration is usually subject to a complex set of push and pull forces, where push forces relate to the source area while pull factors relate to the destination. These forces are in constant flux, as much as environmental change, and interact with socio-economic and political conditions including state or government decision making powers, which can tip the balance at any point by either denying movement or the right to settle elsewhere. The paper focuses on how environmental change and environmental hazards contribute to the migration by exploring the mechanisms through which vulnerability and migration are linked—via livelihoods, relocation policies, and other factors. The paper begins by outlining important definitions of what is environmentally induced migration. The paper also considers the question of whether migration is a process that reduces or increases vulnerability. The paper draws on multidisciplinary literature including ecology, environment, and climate change; sociology of migration; anthropology of displacement; and economics; but also on preliminary from various case studies in Egypt, Vietnam, and Mozambique.