Search results for "SIGNATURE"
showing 10 items of 218 documents
2016
Abstract. We analyze polar stratospheric cloud (PSC) signatures in airborne MIPAS-STR (Michelson Interferometer for Passive Atmospheric Sounding – STRatospheric aircraft) observations in the spectral regions from 725 to 990 and 1150 to 1350 cm−1 under conditions suitable for the existence of nitric acid trihydrate (NAT) above northern Scandinavia on 11 December 2011. The high-resolution infrared limb emission spectra of MIPAS-STR show a characteristic “shoulder-like” signature in the spectral region around 820 cm−1, which is attributed to the ν2 symmetric deformation mode of NO3− in β-NAT. Using radiative transfer calculations involving Mie and T-Matrix methods, the spectral signatures of s…
Iron isotope signature of magnetofossils and oceanic biogeochemical changes through the Middle Eocene Climatic Optimum.
2021
21 pages; International audience; Magnetotactic bacteria (MTB) intracellularly precipitate magnetite (Fe3O4) crystals that can be preserved in the geological record. When MTB die, the so-called magnetofossils constitute valuable proxies for paleoenvironmental reconstructions and are suspected to represent some of the oldest traces of biomineralization on Earth. Yet, the biogenicity of putative magnetofossils found in ancient terrestrial and extra-terrestrial samples is still largely debated and their significance for past climate still holds uncertainties. Here we studied a sedimentary sequence from the Indian Ocean (ODP Hole 711A) recording the Middle Eocene Climatic Optimum (MECO) through…
Inference of the Life Cycle of Environmental Phages from Genomic Signature Distances to Their Hosts
2023
The environmental impact of uncultured phages is shaped by their preferred life cycle (lytic or lysogenic). However, our ability to predict it is very limited. We aimed to discriminate between lytic and lysogenic phages by comparing the similarity of their genomic signatures to those of their hosts, reflecting their co-evolution. We tested two approaches: (1) similarities of tetramer relative frequencies, (2) alignment-free comparisons based on exact k = 14 oligonucleotide matches. First, we explored 5126 reference bacterial host strains and 284 associated phages and found an approximate threshold for distinguishing lysogenic and lytic phages using both oligonucleotide-based methods. The an…
Sexes in gynodioeciousGeranium sylvaticumdo not differ in their isotopic signature or photosynthetic capacity
2017
• In gynodioecious plants, females are expected to produce more or better seeds than hermaphrodites in order to be maintained within the same population. Even though rarely measured, higher seed production can be achieved through differences in physiology. • In this work, we measured sexual dimorphism in several physiological traits in the gynodioecious plant Geranium sylvaticum. Photosynthetic rate, stomatal conductivity, transpiration rate, water use efficiency and isotopic signatures were measured in plants growing in two habitats differing in light availability. • Females have been reported to produce more seeds than hermaphrodites. However, we did not observe any significant difference…
Assigning Elephant Ivory with Stable Isotopes
2016
The international ivory trade remains one of the world’s most controversial wildlife trade issues. One of the main arguments for the trade prohibition is the fact that it is very difficult to distinguish legal from illegal ivory in the markets, so that the legal ivory trade would provide a perfect cover for smuggling. The purpose of this study was to analyze the variability of isotope ratios in ivory samples from Appendix I and II elephant populations in Africa to validate their potential for forensic purposes more quantitatively. We selected a subset of 293 data of ivory samples from the www.ivoryid.org database that stores isotopic ratios of δ13C, δ15N, δ18O, δ2H, and δ34S from more than …
(no title)
1999
We propose hereafter that the signature of the Space-Time metric (+++-) is not anymore frozen at the Planck scale and presents quantum fluctuations (+++±) untill 0 scale where it becomes Euclidean (++++). (i) At the albraic level we suggest an oscillation path (3,1) (4,0) exluding (2,2). We built the quotient topological space describing the superposition of the Lorentzian and the Riemanian metrics. In terms of quantum groups we evidence a relation between q-deformation and deformation of the signature. We have obtained a new algebraic construction ( a new cocycle bicross products by twisting) which allowed us to unify the Lorentzian and the Euclidean signatures within a unique quantum grou…
Fluid geochemistry in a low-enthalpy geothermal field along a sector of southern Apennines chain (Italy)
2020
Abstract The chemical and isotopic features of the fluids (water and gases) in the Lucane thermal area (southern Italy) have been investigated in order to verify their origin, water temperature in the geothermal reservoir, and to recognize the main natural processes concerning the water composition during ascent towards the surface. The Lucane geothermal system is placed in the southern sector of the Apennines chains, a seismically active area, close to the southern base of the Mt. Alpi carbonate massif. Along the study area, two main sets of high-angle faults form an almost orthogonal fault system that, as suggested by local structural geology, acts as a preferential pathway for uprising d…
Abstract A24: Bone marrow hematopoietic adaptation as a sensor of early, pre-invasive, epithelial malignancy
2018
Abstract Tumor development and progression is in part dependent on the ability of bystander cells, mostly of bone marrow (BM) origin, to establish a pro-tumorigenic microenvironment. We hypothesized that signs of the cross-talk between elements of the tumor microenvironment and the BM can be identified in the very early phases of cancer development, being finalized to the instruction of a tumor-promoting hematopoiesis. By integrating in situ BM histopathological and immunophenotypical analyses with flow cytometry and gene expression profiling of hematopoietic populations in a spontaneous mouse model of breast carcinogenesis (MMTV/NeuT) we investigated the occurrence and quality of modificat…
A gene expression signature to characterize human lung adenocarcinoma cancer stem cells.
2018
e20547Background: Treatment resistance is linked to cancer stem cells (CSCs), a highly tumorigenic subpopulation of cells with the ability to grow as spheres in non-adherent conditions. The aim of ...