Search results for "Eris"

Optimal modalities for radiative transfer-neural network estimation of canopy biophysical characteristics: Evaluation over an agricultural area with …

2011

International audience; Neural networks trained over radiative transfer simulations constitute the basis of several operational algorithms to estimate canopy biophysical variables from satellite reflectance measurements. However, only little attention was paid to the training process which has a major impact on retrieval performances. This study focused on the several modalities of the training process within neural network estimation of LAI, FCOVER and FAPAR biophysical variables. Performances were evaluated over both actual experimental observations and model simulations. The SAIL and PROSPECT radiative transfer models were used here to simulate the training and the synthetic test dataset…

Evaluation of deep learning algorithms for national scale landslide susceptibility mapping of Iran

2021

The identification of landslide-prone areas is an essential step in landslide hazard assessment and mitigation of landslide-related losses. In this study, we applied two novel deep learning algorithms, the recurrent neural network (RNN) and convolutional neural network (CNN), for national-scale landslide susceptibility mapping of Iran. We prepared a dataset comprising 4069 historical landslide locations and 11 conditioning factors (altitude, slope degree, profile curvature, distance to river, aspect, plan curvature, distance to road, distance to fault, rainfall, geology and land-sue) to construct a geospatial database and divided the data into the training and the testing dataset. We then d…

A Pluto-like radius and a high albedo for the dwarf planet Eris from an occultation

2011

The dwarf planet Eris is a trans-Neptunian object with an orbital eccentricity of 0.44, an inclination of 44 degrees and a surface composition very similar to that of Pluto. It resides at present at 95.7 astronomical units (1ĝ€‰au is the Earth-Sun distance) from Earth, near its aphelion and more than three times farther than Pluto. Owing to this great distance, measuring its size or detecting a putative atmosphere is difficult. Here we report the observation of a multi-chord stellar occultation by Eris on 6 November 2010 ut. The event is consistent with a spherical shape for Eris, with radius 1,163±6 kilometres, density 2.52±0.05 grams per cm 3 and a high visible geometric albedo,. No nitro…

First M87 Event Horizon Telescope Results. I. the Shadow of the Supermassive Black Hole

2019

When surrounded by a transparent emission region, black holes are expected to reveal a dark shadow caused by gravitational light bending and photon capture at the event horizon. To image and study this phenomenon, we have assembled the Event Horizon Telescope, a global very long baseline interferometry array observing at a wavelength of 1.3 mm. This allows us to reconstruct event-horizon-scale images of the supermassive black hole candidate in the center of the giant elliptical galaxy M87. We have resolved the central compact radio source as an asymmetric bright emission ring with a diameter of 42 ± 3 μas, which is circular and encompasses a central depression in brightness with a flux rati…

Ceramic productions and human interactions during the Early Bronze Age in northern Iberia

2021

The Early Bronze Age ceramic collection found into the caves of La Llana and El Toral III in Asturias (Spain) presents common decoration such as that found in the centre of Cantabrian Spain from the same period, which resembles others found in the Ebro Valley and Atlantic Europe. Therefore, the main objective of this study it is to identify the raw material origin and understand the pottery production process during the Early Bronze Age in the Cantabrian region. A methodological approach based on the chemical and mineralogical analysis of vessels and experimentally fired clay samples collected all over the centre of this region was developed. Furthermore, the post-depositional processes aff…

Late Holocene seasonal temperature variability of the western Scottish shelf (St Kilda) recorded in fossil shells of the bivalve Glycymeris glycymeris

2021

Abstract The North Atlantic Ocean and adjacent shelf seas play a crucial role in global climate. To better constrain long-term natural variability and marine-terrestrial linkages in this region, a network of highly resolved marine archives from the open ocean and continental shelves is needed. In recent decades, bivalve sclerochronology has emerged as a field providing such records from the mid- to high latitudes. In May 2014, dead valves and young live specimens of the bivalve Glycymeris glycymeris were collected at St Kilda, Scotland. A floating chronology spanning 187 years was constructed with fossil shells and radiocarbon dated to 3910–3340 cal yr before present (BP), with a probabilit…

Drivers of shell growth of the bivalve, Callista chione (L. 1758) - Combined it environmental and biological factors

2018

WOS:000426027100014; Seasonal shell growth patterns were analyzed using the stable oxygen and carbon isotope values of live-collected specimens of the bivalve Callista chione from two sites in the Adriatic Sea (Pag and Cetina, Croatia). Micromilling was performed on the shell surface of three shells per site and shell oxygen isotopes of the powder samples were measured. The timing and rate of seasonal shell growth was determined by aligning the delta O-18(shell)-derived temperatures so that the best fit was achieved with the instrumental temperature curve. According to the data, shells grew only at very low rates or not at all during the winter months, i.e., between January and March. Shell…

Volatile-mediated foraging behaviour of three parasitoid species under conditions of dual insect herbivore attack

2016

Infochemicals play an important role in structuring intra-and interspecific interactions. Many parasitoid wasp species rely on herbivory or oviposition-induced plant volatiles (HIPVs/OIPVs) to locate their herbivorous hosts, and must cope with variation in the volatile blends due to factors such as plant/host species, herbivore density or attack by several herbivores. However, little is known about how dual herbivory or changes in herbivore density affect multiple parasitoid species, each attacking a different herbivore, in the same system. In a natural system, we investigated the effect of dual attack on the ability of three parasitoid species to differentiate between volatiles induced by …

2016

Sex differences in ageing rates and lifespan are common in nature, and an enduring puzzle for evolutionary biology. One possibility is that sex-specific mortality rates may result from recessive deleterious alleles in ‘unguarded’ heterogametic X or Z sex chromosomes (the unguarded X hypothesis). Empirical evidence for this is, however, limited. Here, we test a fundamental prediction of the unguarded X hypothesis in Drosophila melanogaster , namely that inbreeding shortens lifespan more in females (the homogametic sex in Drosophila ) than in males. To test for additional sex-specific social effects, we studied the lifespan of males and females kept in isolation, in related same-sex groups, …

Tonoplast aquaporins facilitate lateral root emergence\ud

2016

Pôle SPE IPM UB; International audience; Aquaporins (AQPs) are water channels allowing fast and passive diffusion of water across cell membranes. It was hypothesized that AQPs contribute to cell elongation processes by allowing water influx across the plasma membrane and the tonoplast to maintain adequate turgor pressure. Here, we report that, in Arabidopsis (Arabidopsis thaliana), the highly abundant tonoplast AQP isoforms AtTIP1;1, AtTIP1;2, and AtTIP2;1 facilitate the emergence of new lateral root primordia (LRPs). The number of lateral roots was strongly reduced in the triple tip mutant, whereas the single, double, and triple tip mutants showed no or minor reduction in growth of the mai…