Development of a method of robust rain gauge network optimization based on intensity-duration-frequency results

Based on rainfall intensity-duration-frequency (IDF) curves, fitted in several locations of a given area, a robust optimization approach is proposed to identify the best locations to install new rain gauges. The advantage of robust optimization is that the resulting design solutions yield networks which behave acceptably under hydrological variability. Robust optimization can overcome the problem of selecting representative rainfall events when building the optimization process. This paper reports an original approach based on Montana IDF model parameters. The latter are assumed to be geostatistical variables, and their spatial interdependence is taken into account through the adoption of cross-variograms in the kriging process. The problem of optimally locating a fixed number of new monitoring stations based on an existing rain gauge network is addressed. The objective function is based on the mean spatial kriging variance and rainfall variogram structure using a variance-reduction method. Hydrological variability was taken into account by considering and implementing several return periods to define the robust objective function. Variance minimization is performed using a simulated annealing algorithm. In addition, knowledge of the time horizon is needed for the computation of the robust objective function. A short- and a long-term horizon were studied, and optimal networks are identified for each. The method developed is applied to north Tunisia (area = 21 000 km2). Data inputs for the variogram analysis were IDF curves provided by the hydrological bureau and available for 14 tipping bucket type rain gauges. The recording period was from 1962 to 2001, depending on the station. The study concerns an imaginary network augmentation based on the network configuration in 1973, which is a very significant year in Tunisia because there was an exceptional regional flood event in March 1973. This network consisted of 13 stations and did not meet World Meteorological Organization (WMO) recommendations for the minimum spatial density. Therefore, it is proposed to augment it by 25, 50, 100 and 160% virtually, which is the rate that would meet WMO requirements. Results suggest that for a given augmentation robust networks remain stable overall for the two time horizons

Leiomyosarcome du Rein: A Propos D’un Cas

Le léiomyosarcome du rein est une tumeur rare. Les auteurs ont rapporté l’observation d’un homme âgé de 45 ans, chez lequel le diagnostic d’une tumeur rétropéritoénale gauche a été posé lors de l’exploration de douleurs du flanc gauche associées à une altération de l’état général et ce par l’imagerie (Echographie et scanner abdominal). La laparotomie exploratrice avait conclu à une tumeur rénale gauche localement évoluée, une néphrectomie élargie a été réalisée et l’histologie était en faveur d’un léiomyosarcome rénal. Une récidive locale a été diagnostiquée après un recul de 6 mois. Après une nouvelle laparotomie, l’abstention était de mise devant le caractère évolué de la récidive. Le but de cette observation est double. Le premier, est la nécessité de faire un diagnostic précoce, afin d’intervenir sur une tumeur de petite taille, plus accessible à la chirurgie. Le second, est de discuter la place du traitement adjuvant, qui pourrait réduire le risque de récidive précoce.Mots clés : Léiomyosarcome, rei

Primary thyroid lymphoma: Case report and review of the literature

AbstractPrimary thyroid lymphoma (PTL) is defined as a lymphoma involving only the thyroid gland or both thyroid gland and neck lymph nodes, without contiguous spread or distant metastases from other areas of involvement at diagnosis. Despite its rarity, PTL should be promptly recognized because its management is quite different from the treatment of other neoplasms of the thyroid gland.In the present study, we report a case of PTL treated by surgery and adjuvant chemotherapy. Otherwise, literature review allowed us to define main characteristics of this located lymphoma

Evapotranspiration and evaporation/transpiration partitioning with dual source energy balance models in agricultural lands

EvapoTranspiration (ET) is an important component of the water cycle, especially in semi-arid lands. Its quantification is crucial for a sustainable management of scarce water resources. A way to quantify ET is to exploit the available surface temperature data from remote sensing as a signature of the surface energy balance, including the latent heat flux. Remotely sensed energy balance models enable to estimate stress levels and, in turn, the water status of most continental surfaces. The evaporation and transpiration components of ET are also just as important in agricultural water management and ecosystem health monitoring. Single temperatures can be used with dual source energy balance models but rely on specific assumptions on raw levels of plant water stress to get both components out of a single source of information. Additional information from remote sensing data are thus required, either something specifically related to evaporation (such as surface water content) or transpiration (such as PRI or fluorescence). This works evaluates the SPARSE dual source energy balance model ability to compute not only total ET, but also water stress and transpiration/evaporation components. First, the theoretical limits of the ET component retrieval are assessed through a simulation experiment using both retrieval and prescribed modes of SPARSE with the sole surface temperature. A similar work is performed with an additional constraint, the topsoil surface soil moisture level, showing the significant improvement on the retrieval. Then, a flux dataset acquired over rainfed wheat is used to check the robustness of both stress levels and ET retrievals. In particular, retrieval of the evaporation and transpiration components is assessed in both conditions (forcing by the sole temperature or the combination of temperature and soil moisture). In our example, there is no significant difference in the performance of the total ET retrieval, since the evaporation rate retrieved from the sole surface temperature is already fairly close to the one we can reconstruct from observed surface soil moisture time series, but current work is underway to test it over other plots.</p

The Photochemical Reflectance Index (PRI) and the vegetation temperature as indicators of water stress and transpiration in Mediterranean olive grove

M2GARSS.Mediterranean and Middle-East Geoscience and Remote Sensing Symposium, Tunis, TUN, 09-/03/2020 - 09/03/2020To increase the olive tree water use efficiency, an early tracking of water stress is crucial. Several indices based on the near-infrared (the vegetation temperature) and the visible (The photochemical reflectance index (PRI)) spectral bands have shown to be useful to remotely assess the tree eco-physiological functioning status. First, at plant scale, we analyzed the relations between close-range remote sensing measurements (PRI, vegetation temperature) and the plant water stress measurements (plant available water (PAW), the transpiration, the water stress index...). The vegetation temperature was closely associated with the transpiration and the plant water stress indicator. However, the PRI, which was promising as an indicator of the water functioning of the plant, was not able to detect water stress over complex crown of isolated tree due to its high sensitivity to the structure

Arabidopsis thaliana tolerates iron deficiency more than Thellungiella salsuginea by inducing metabolic changes at the root level

Several studies have used A. thaliana as a model to identify the physiological and molecular mechanisms underlying iron deficiency tolerance in plants. Here, Arabidopsis thaliana and Thellungiella salsuginea were used to investigate the differential responses to iron deficiency of these two species. Plants were cultivated in hydroponic medium containing 5 or 0 μM Fe, for 10 days. Results showed that rosette biomass was more reduced in T. salsuginea than in A. thaliana when grown on Fe-deficient medium. As a marker for iron deficiency tolerance, the induction of ferric chelate reductase (FCR) and phosphoenolpyruvate carboxylase (PEPC) activities was observed only in A. thaliana roots. In addition, we found that the accumulation of phenolic acids in roots of N1438 ecotype of A. thaliana was stimulated by Fe deficiency. Furthermore, an increase of flavonoids content in the root and exudates was observed under Fe-deficiency in this ecotype. Unlike other abiotic stresses, it appears that iron deficiency effects were more pronounced in Thellungiella than in Arabidopsis. The higher tolerance of the Arabidopsis plant to iron deficiency may be due to the metabolic changes occurring in the roots