8 research outputs found
Genetic full waveform inversion to characterise fractures
Active seismic methodologies provide a non-invasive tool to remotely characterise the
physical properties of fractures at a wide range of scales, and have a positive impact in
helping to solve rock engineering problems in a variety of geo-industrial applications.
With current advances in seismic processing tools, such as full waveform inversion
(FWI), and accurate models of seismic wave interaction with fractures, seismic characterisation
of fractures can be tackled by utilising the entire seismic wavefield recorded at
the receiver locations. A two-step strategy, using the genetic algorithm (GA) for global
optimisation and the Neighbourhood Algorithm (NA) for evaluating uncertainties, was
developed to simultaneously estimate the fracture properties (both fracture specific
stiffness and equivalent fracture stiffness) and the background material properties directly
from seismic waveforms. The optimisation involves minimising the difference
between the observed (measured) and forward-modelled full waveforms through the
finite difference code WAVE3D.
The development, named Genetic Algorithm Full-Waveform Fracture Inversion (GAFWFI),
looks beyond conventional seismic methods which focus on characterising
fracture-induced anisotropy, by reducing the need to manually condition the data (e.g.
manual picking of seismic phases), and by providing a robust means to explore multiple
solutions. The development also allows the gap between different representations
of fracturing to be bridged within a comprehensive method which can employ both
discrete fracture and effective fracture models.
GA-FWFI is tested initially on synthetic ultrasonic experiments with parallel fractures.
Results confirm that the method can effectively invert for physical properties
such as fracture stiffness, location, background material properties, while the posterior
probability density (PPD) show that inversions are very well constrained. GA-FWFI
is then applied to waveforms from a laboratory experiment investigating fracture slip
and again results show high degree of accuracy.
GA-FWFI is then utilised to unveil the coupling between discrete fracture networks
(DFNs) and their equivalent fracture zone properties. The results reveal that the
transition from a medium with open cracks to one with welded interfaces leads to the
equivalent media having the equivalent medium stiffness non-linearly related to the
crack specific stiffness. An attribute χ is proposed which helps guide the interpretation
of a cracked medium by giving a range of likely values for crack size and crack stiffness.
This work paves the way for novel strategies to seismically characterise fractures
Esperimenti di inversione Full-Waveform acustica di dati sintetici elastici
La Full Waveform Inversion (FWI) è una procedura non-lineare di data-fitting che ha la finalità di costruire un modello di velocità del sottosuolo accurato e ad alta denizione. Tale tecnica aggiorna iterativamente un modello stimato della sottosupercie e calcola il corrispondente dato sismico sintetico (dato predetto) per minimizzare lo scarto tra esso e il dato sismico osservato (dato registrato).
La FWI è utilizzata per estrarre dal dato sismico numerose proprietà fisiche; tuttavia, l'utilizzo di questa tecnica è limitato da alcuni problemi quali, ad esempio, il costo computazionale, la forte non-linearità (presenza di numerosi minimi locali della funzione oggetto) e la non-univocità .
Per mitigare i problemi sopracitati vengono operate approssimazioni dell'equazione d'onda nella simulazione del dato predetto. Una comune approssimazione è quella di considerare la Terra come un mezzo puramente acustico, ignorando gli effetti dell'elasticità , attenuazione e anisotropia. Ciò comporta inevitabilmente una modellazione non corretta delle ampiezze delle onde sismiche in particolar modo in funzione dell'offset (effetto AVO - Amplitude Versus Oset), pregiudicando l'inversione e quindi l'accuratezza del modello di velocità calcolato.
In questo lavoro di tesi ci proponiamo, quindi, di analizzare le conseguenze, i limiti e i benefici dell'approssimazione acustica nell'inversione di un dato sintetico elastico. Per la valutazione degli scopi dello studio, sono state effettuate una serie di inversioni per diversi modelli in due dimensioni. Test preliminari su modelli semplici a strati piano paralleli, sono stati generalizzati per valutare l'approssimazione acustica sul modello complesso Marmousi2.
La FWI in approssimazione acustica fornisce dei modelli di velocità con evidenti artefatti soprattutto se vi sono forti discontinuità nel campo di velocità S. A causa del fenomeno del cycle-skipping, rotazioni di fase e brusche variazioni di ampiezza del campo elastico riflesso vengono interpretate erroneamente in dominio acustico comportando la simulazione di cinematiche differenti da quelle attese. Per contro, la FWI acustica produce risultati affidabili quando il campo di velocita delle onde S
risulta smooth, ovvero in presenza di dati sismici osservati con deboli fasi convertite P-S e deboli effetti AVO
Red deer exploitation strategies during ancient Neolithic in central-Adriatic Italy: the case of Colle Santo Stefano (Abruzzes)
International audienceIn this paper we present the results of an integrated approach combining zooarchaeological, technological and macroscopic use-wear analyses carried out on the osseous material assemblage of Cervus elaphus recovered in the Early Neolithic site of Colle Santo Stefano (Italy). This study, inedited for the Neolithic Italian contexts, seeks to examine the available data on red deer exploitation strategies in order to highlight the relationship between animal acquisition for alimentary consumption and its treatment and transformation for domestic purposes by the first agro-pastoral societies. Despite the limited sample, the results obtained allowed to define not only alimentary-technical imbrication but also the existent relationship with the other techno-complexes recovered in the site
Red deer exploitation strategies during ancient Neolithic in central-Adriatic Italy: the case of Colle Santo Stefano (Abruzzes)
International audienceIn this paper we present the results of an integrated approach combining zooarchaeological, technological and macroscopic use-wear analyses carried out on the osseous material assemblage of Cervus elaphus recovered in the Early Neolithic site of Colle Santo Stefano (Italy). This study, inedited for the Neolithic Italian contexts, seeks to examine the available data on red deer exploitation strategies in order to highlight the relationship between animal acquisition for alimentary consumption and its treatment and transformation for domestic purposes by the first agro-pastoral societies. Despite the limited sample, the results obtained allowed to define not only alimentary-technical imbrication but also the existent relationship with the other techno-complexes recovered in the site
Dataset on antioxidant metabolites and enzymes activities of freshly harvested sweet cherries (Prunus avium L.) of Campania accessions
In this article, we reported the original data obtained by the study of metabolites and enzymes involved in sweet cherry antioxidant system. We measured hydrogen peroxide (H2O2) and malondialdehyde (MDA), which are indicator of oxidative stress. Moreover, we measured the concentration of reduced and oxidized ascorbate and glutathione that are involved in ROS detoxification together with phenolics, anthocyanins and tocopherols. Among antioxidant enzymes, we analyzed the activities of ascorbate peroxidase (APX; EC 1.11.1.11), and the soluble and bound forms of polyphenol oxidase (PPO; EC 1.10.3.1) and guaiacol peroxidase (POD; EC 1.11.1.7). The data reported in this paper are related to the research article âMetabolic characterization and antioxidant activity in sweet cherry (Prunus avium L.) Campania accessionsâ, authored by Mirto et al. (2018) [1]
Durum wheat seedling responses to simultaneous high light and salinity involve a fine reconfiguration of amino acids and carbohydrate metabolism
Durum wheat plants are extremely sensitive to drought and salinity during seedling and early development
stages. Their responses to stresses have been extensively studied to provide new metabolic targets and
improving the tolerance to adverse environments. However, most of these studies have been performed in
growth chambers under low light (300–350 μmol m–2 s–1 PAR, LL). However, in nature plants have to
face frequent fluctuations of light intensities that often exceed their photosynthetic capacity (900–2000
μmol m–2 s–1). In this study we investigated the physiological and metabolic changes potentially involved
in osmotic adjustment and antioxidant defense in durum wheat seedlings under high light (HL) and
salinity. The combined application of the two stresses decreased the water potential and stomatal
conductance without reducing the photosynthetic efficiency of the plants. Glycine betaine synthesis was
inhibited, proline and glutamate content decreased, while GABA, amides and minor amino acids
increased. The expression level and enzymatic activities of Δ1-pyrroline-5-carboxylate synthetase,
asparagine synthetase and glutamate decarboxylase, as well as other enzymatic activities of nitrogen and
carbon metabolism, were analyzed. Antioxidant enzymes and metabolites were also considered. The
results showed that the complex interplay seen in durum wheat plants under salinity at LL was simplified:
glycine betaine and antioxidants did not play a main role. On the contrary, the fine tuning of few specific
primary metabolites (GABA, amides, minor amino acids and hexoses) remodeled metabolism and defense
processes, playing a key role in the response to simultaneous stresses.Durum wheat plants are extremely sensitive to drought and salinity during seedling and early development stages. Their responses to stresses have been extensively studied to provide new metabolic targets and improving the tolerance to adverse environments. Most of these studies have been performed in growth chambers under low light [300–350 µmol m−2 s−1 photosynthetically active radiation (PAR), LL]. However, in nature plants have to face frequent fluctuations of light intensities that often exceed their photosynthetic capacity (900–2000 µmol m−2 s−1). In this study we investigated the physiological and metabolic changes potentially involved in osmotic adjustment and antioxidant defense in durum wheat seedlings under high light (HL) and salinity. The combined application of the two stresses decreased the water potential and stomatal conductance without reducing the photosynthetic efficiency of the plants. Glycine betaine (GB) synthesis was inhibited, proline and glutamate content decreased, while γ-aminobutyric acid (GABA), amides and minor amino acids increased. The expression level and enzymatic activities of Δ1-pyrroline-5-carboxylate synthetase, asparagine synthetase and glutamate decarboxylase, as well as other enzymatic activities of nitrogen and carbon metabolism, were analyzed. Antioxidant enzymes and metabolites were also considered. The results showed that the complex interplay seen in durum wheat plants under salinity at LL was simplified: GB and antioxidants did not play a main role. On the contrary, the fine tuning of few specific primary metabolites (GABA, amides, minor amino acids and hexoses) remodeled metabolism and defense processes, playing a key role in the response to simultaneous stresses
Downregulation of praja2 restrains endocytosis and boosts tyrosine kinase receptors in kidney cancer
Abstract Clear cell renal cell carcinoma (ccRCC) is the most common kidney cancer in the adult population. Late diagnosis, resistance to therapeutics and recurrence of metastatic lesions account for the highest mortality rate among kidney cancer patients. Identifying novel biomarkers for early cancer detection and elucidating the mechanisms underlying ccRCC will provide clues to treat this aggressive malignant tumor. Here, we report that the ubiquitin ligase praja2 forms a complex with-and ubiquitylates the AP2 adapter complex, contributing to receptor endocytosis and clearance. In human RCC tissues and cells, downregulation of praja2 by oncogenic miRNAs (oncomiRs) and the proteasome markedly impairs endocytosis and clearance of the epidermal growth factor receptor (EGFR), and amplifies downstream mitogenic and proliferative signaling. Restoring praja2 levels in RCC cells downregulates EGFR, rewires cancer cell metabolism and ultimately inhibits tumor cell growth and metastasis. Accordingly, genetic ablation of praja2 in mice upregulates RTKs (i.e. EGFR and VEGFR) and induces epithelial and vascular alterations in the kidney tissue. In summary, our findings identify a regulatory loop between oncomiRs and the ubiquitin proteasome system that finely controls RTKs endocytosis and clearance, positively impacting mitogenic signaling and kidney cancer growth