Regional scale rain-forest height mapping using regression-kriging of spaceborneand airborne lidar data: application on French Guiana

IGARSS 2015, Milan, ITA, 26-/07/2015 - 31/07/2015International audienceLiDAR remote sensing has been shown to be a good technique for the estimation of forest parameters such as canopy heights and aboveground biomass. Whilst airborne LiDAR data are in general very dense but only available over small areas due to the cost of their acquisition, spaceborne LiDAR data acquired from the Geoscience Laser Altimeter System (GLAS) have a coarser acquisition density associated with a global cover. It is therefore valuable to analyze the integration relevance of canopy heights estimated from LiDAR sensors with ancillary data such as geological, meteorological, and phenological variables in order to propose a forest canopy height map with good precision and high spatial resolution.In this study, canopy heights extracted from both airborne and spaceborne LiDAR, were first extrapolated from available environmental data. The estimated canopy height maps using random forest (RF) regression from the airborne or GLAS calibration datasets showed similar precisions (RMSE better than 6.5 m). In order to improve the precision of the canopy height estimates regression-kriging (kriging of RF regression residuals) was used. Results indicated an improvement in the RMSE (decrease from 6.5 to 4.2 m) for the regression-kriging maps from the GLAS dataset, and from 5.8 to 1.8 m for the regression-kriging map from the airborne LiDAR dataset

Determinants of the return to hometowns after the accident at Fukushima Dai-ichi nuclear power plant: a case study for the village of Kawauchi

The Great East Japan Earthquake in March 2011 destroyed the Fukushima Dai-ichi Nuclear Power Plant (FNPP) and almost all residents in a 20 km radius from the plant eventually evacuated. FNPP reactors were stabilised in December 2011; some evacuees decided to return to their hometowns, and the other evacuees remained. Efforts were made to identify the determinants that affect the decision to return home in order to promote recovery of the surrounding area of FNPP. Seventyone residents who had not returned to hometown and 56 residents who had returned were selected. Logistic regression analysis adjusted for confounding factors showed that being female [odds ratio (OR): 2.43, p=5 0.03], living in areas with relatively higher ambient doses (OR: 3.60, p=50.01) and expressing anxiety over radiation exposure (OR: 8.91, p < 0.01) were independently associated with decisions not to return. Results of this study suggest the importance of active participation by scientists and local authorities in communicating the risk to the general population involved in returning home

Asteroseismology and Interferometry

Asteroseismology provides us with a unique opportunity to improve our understanding of stellar structure and evolution. Recent developments, including the first systematic studies of solar-like pulsators, have boosted the impact of this field of research within Astrophysics and have led to a significant increase in the size of the research community. In the present paper we start by reviewing the basic observational and theoretical properties of classical and solar-like pulsators and present results from some of the most recent and outstanding studies of these stars. We centre our review on those classes of pulsators for which interferometric studies are expected to provide a significant input. We discuss current limitations to asteroseismic studies, including difficulties in mode identification and in the accurate determination of global parameters of pulsating stars, and, after a brief review of those aspects of interferometry that are most relevant in this context, anticipate how interferometric observations may contribute to overcome these limitations. Moreover, we present results of recent pilot studies of pulsating stars involving both asteroseismic and interferometric constraints and look into the future, summarizing ongoing efforts concerning the development of future instruments and satellite missions which are expected to have an impact in this field of research.Comment: Version as published in The Astronomy and Astrophysics Review, Volume 14, Issue 3-4, pp. 217-36

Carotid Body AT4 Receptor Expression and its Upregulation in Chronic Hypoxia

Hypoxia regulates the local expression of angiotensin-generating system in the rat carotid body and the me-tabolite angiotensin IV (Ang IV) may be involved in the modulation of carotid body function. We tested the hypothesis that Ang IV-binding angiotensin AT4 receptors play a role in the adaptive change of the carotid body in hypoxia. The expression and localization of Ang IV-binding sites and AT4 receptors in the rat carotid bodies were studied with histochemistry. Specific fluorescein-labeled Ang IV binding sites and positive staining of AT4 immunoreactivity were mainly found in lobules in the carotid body. Double-labeling study showed the AT4 receptor was localized in glomus cells containing tyrosine hydroxylase, suggesting the expression in the chemosensitive cells. Intriguingly, the Ang IV-binding and AT4 immunoreactivity were more intense in the carotid body of chronically hypoxic (CH) rats (breathing 10% oxygen for 4 weeks) than the normoxic (Nx) control. Also, the protein level of AT4 receptor was doubled in the CH comparing with the Nx group, supporting an upregulation of the expression in hypoxia. To examine if Ang IV induces intracellular Ca2+ response in the carotid body, cytosolic calcium ([Ca2+]i) was measured by spectrofluorimetry in fura-2-loaded glomus cells dissociated from CH and Nx carotid bodies. Exogenous Ang IV elevated [Ca2+]i in the glomus cells and the Ang IV response was significantly greater in the CH than the Nx group. Hence, hypoxia induces an upregulation of the expression of AT4 receptors in the glomus cells of the carotid body with an increase in the Ang IV-induced [Ca2+]i elevation. This may be an additional pathway enhancing the Ang II action for the activation of chemoreflex in the hypoxic response during chronic hypoxia

Chronic production of angiotensin IV in the brain leads to hypertension that is reversible with an angiotensin II AT1 receptor antagonist

Angiotensin IV (Ang IV) is a metabolite of the potent vasoconstrictor angiotensin II (Ang II). Because specific binding sites for this peptide have been reported in numerous tissues including the brain, it has been suggested that a specific Ang IV receptor (AT4) might exist. Bolus injection of Ang IV in brain ventricles has been implicated in learning, memory, and localized vasodilatation. However, the functions of Ang IV in a physiological context are still unknown. In this study, we generated a transgenic (TG) mouse model that chronically releases Ang IV peptide specifically in the brain. TG mice were found to be hypertensive by the tail-cuff method as compared with control littermates. Treatment with the angiotensin-converting enzyme inhibitor captopril had no effect on blood pressure, but surprisingly treatment with the Ang II AT1 receptor antagonist candesartan normalized the blood pressure despite the fact that the levels of Ang IV in the brains of TG mice were only 4-fold elevated over the normal endogenous level of Ang peptides. Calcium mobilization assays performed on cultured CHO cells chronically transfected with the AT1 receptor confirm that low-dose Ang IV can mobilize calcium via the AT1 receptor only in the presence of Ang II, consistent with an allosteric mechanism. These results suggest that chronic elevation of Ang IV in the brain can induce hypertension that can be treated with angiotensin II AT1 receptor antagonists

Risk communication in the recovery phase after a nuclear accident: the contribution of the “co-expertise process”

Risk communication in post-nuclear accident situations faces many challenges related to the limited knowledge of experts about the actual situation in the affected communities, as well as of the affected people about radiological risk combined with their distrust of authorities and experts. In such an anxiety-provoking context, the co-expertise approach recommended by the ICRP combining technical expertise, citizen participation and two-way communication has shown that it was an effective approach for restoring trust between the experts and the people concerned and developing, among the latter, a practical radiological protection culture. In essence, technical-oriented risk communication is not sufficient alone. A dialogue with affected people is necessary in combination with measurements of radiation associated with their daily life in order to gain their participation in the co-expertise process and to progressively restore confidence in them and trust in authorities and experts. The article highlights the salient features of the co-expertise process in relation to risk communication

An analysis of the desire to make radiation measurements and to dialogue with experts among the residents of Tomioka town, Fukushima Prefecture: about the implementation of the co-expertise process

The article presents a contribution concerning the desire to make radiation measurements and to dialogue with experts among the residents of Tomioka town close to the Fukushima Daiichi Nuclear Power Plant in Japan at the time of the lifting of the relocation order in 2017. Relying on data from a questionnaire conducted at the same time with approximately 8000 residents aged 20 years or older who lived in Tomioka before the accident, a logistic regression analysis was performed to identify retrospectively the factors having driven these desires. The results shed some light on the motivation of affected people to engage in the co-expertise process implemented in Tomioka by experts from Nagasaki University and local authorities. In essence there are two significant results: (i) the people who have the desire to make radiation measurements are those who are reluctant to eat foods produced in the town and who already had an experience of radiation measurement, (ii) the people who have the desire to dialogue with experts about radiation exposure and health effects are above 60 years old and are reluctant to eat foods produced in the town and to drink tap water. In both cases people can imagine living in Tomioka now and in the future. Perspectives regarding future research are envisaged

Report on the 24th Fukushima Dialogue “Creating the Future of Fukushima Together With The Next Generation”

The 24th Fukushima Dialogue, a stakeholder meeting to discuss the future of the recovery phase in Fukushima Prefecture among the younger generation, was held in the town of Naraha in the Futaba district of the Fukushima Prefecture, in November 2022. Following a series of presentations, participants to the meeting aged 18 to 35 discussed the current challenges of the reconstruction activities in the Fukushima Prefecture and what is needed to improve the situation. The Dialogue revealed that the younger generation has difficulty in grasping what is meant by reconstruction and readily distinguishes between the “large” reconstruction of authorities and the “small” one of individuals. It also revealed that the Fukushima accident had a strong impact on the sense of belonging of its inhabitants to the region and that they now aspire to build a new identity by regaining control of their lives, even if it is sometimes a painful process. Finally, the Dialogue brought to light that the younger generation is willing and ready to engage in the decision-making process related to the recovery phase in the Fukushima Prefecture