648 research outputs found
Improving predictive power of physically based rainfall-induced shallow landslide models: a probabilistic approach
Distributed models to forecast the spatial and temporal occurrence of
rainfall-induced shallow landslides are based on deterministic laws. These
models extend spatially the static stability models adopted in geotechnical
engineering, and adopt an infinite-slope geometry to balance the resisting and
the driving forces acting on the sliding mass. An infiltration model is used to
determine how rainfall changes pore-water conditions, modulating the local
stability/instability conditions. A problem with the operation of the existing
models lays in the difficulty in obtaining accurate values for the several
variables that describe the material properties of the slopes. The problem is
particularly severe when the models are applied over large areas, for which
sufficient information on the geotechnical and hydrological conditions of the
slopes is not generally available. To help solve the problem, we propose a
probabilistic Monte Carlo approach to the distributed modeling of
rainfall-induced shallow landslides. For the purpose, we have modified the
Transient Rainfall Infiltration and Grid-Based Regional Slope-Stability
Analysis (TRIGRS) code. The new code (TRIGRS-P) adopts a probabilistic approach
to compute, on a cell-by-cell basis, transient pore-pressure changes and
related changes in the factor of safety due to rainfall infiltration.
Infiltration is modeled using analytical solutions of partial differential
equations describing one-dimensional vertical flow in isotropic, homogeneous
materials. Both saturated and unsaturated soil conditions can be considered.
TRIGRS-P copes with the natural variability inherent to the mechanical and
hydrological properties of the slope materials by allowing values of the TRIGRS
model input parameters to be sampled randomly from a given probability
distribution. [..]Comment: 25 pages, 14 figures, 9 tables. Revised version; accepted for
publication in Geoscientific Model Development on 13 February 201
Trapped in the morphospace: The relationship between morphological integration and functional performance
The evolution of complex morphological structures can be characterized by the interplay between different anatomical regions evolving under functional integration in response to shared selective pressures. Using the highly derived humeral morphology of talpid moles as a model, here we test whether functional performance is linked to increased levels of evolutionary integration between humerus subunits and, if so, what the strength is of the relationship. Combining two-dimensional geometric morphometrics, phylogenetic comparative methods, and functional landscape modeling, we demonstrate that the high biomechanical performance of subterranean moles’ humeri is coupled with elevated levels of integration, whereas taxa with low-performance values show intermediate or low integration. Theoretical morphs occurring in high-performance areas of the functional landscape are not occupied by any species, and show a marked drop in covariation levels, suggesting the existence of a strong relationship between integration and performance in the evolution of talpid moles’ humeri. We argue that the relative temporal invariance of the subterranean environment may have contributed to stabilize humeral morphology, trapping subterranean moles in a narrow region of the landscape and impeding any attempt to reposition on a new ascending slope
Ricerca del grano tenero in miscela con il duro negli sfarinati e nelle paste variamente essiccate
Il riconoscimento dell'uso del grano tenero nella produzione della pasta alimentare si basa sull'analisi gas cromatografica deli esteri degli steroli previo isolamento della frazione lipidica. Il metodo consente di calcolare la percentuale di grano tenero utilizzato sia negli sfarinati sia nelle paste
Salivary cytokines and airways disease severity in patients with cystic fibrosis
About 50% of patients with cystic fibrosis (CF) have sinonasal complications, which include inferior turbinate hypertrophy (NTH) and/or nasal polyposis (NP), and different degrees of lung disease, which represents the main cause of mortality. Monitoring of sinonasal disease requires complex instrumental procedures, while monitoring of lung inflammation requires invasive collection of bronchoalveolar lavage fluid. The aim of this study was to investigate the associations between salivary cytokines levels and CF-related airway diseases. Salivary biochemical parameters and cytokines, i.e., interleukin-6 (IL-6), IL-8, and tumor necrosis factor alpha (TNF-α), were analyzed in resting saliva from healthy subjects and patients with CF. Patients with CF showed significantly higher levels of salivary chloride, IL-6, IL-8, and TNF-α and lower calcium levels than healthy subjects. Among patients with CF, IL-6 and IL-8 were significantly higher in patients with NTH, while TNF-α was significantly lower in patients with NP. A decreasing trend of TNF-α in patients with severe lung disease was also observed. On the other hand, we did not find significant correlation between cytokine levels and Pseudomonas aeruginosa or Stenotrophomonas maltophilia colonization. These preliminary results suggest that salivary IL-6 and IL-8 levels increase during the acute phase of sinonasal disease (i.e., NTH), while the end stages of pulmonary disease and sinonasal disease (i.e., NP) show decreased TNF-α level
Seeing through the skin: dermal light sensitivity provides cryptism in moorish gecko
Concealment by means of colour change is a pre-eminent deceptive mechanism used by both predators and prey. The moorish gecko Tarentola mauritanica is able to blend into the background by either darkening or paling according to the substrate darkness. Here we examined the functioning of background perception in moorish gecko. We experimentally excluded the involvement of melanophore-stimulating hormone in camouflage. Blindfolded individuals change their colour consistently with the background. Surprisingly, individuals with covered flanks were not able to change colour, no matter whether they were allowed to see the substrate or not. Accordingly, we found high levels of opsin transcript and protein in the flank region of the gecko. These observations suggest that T.mauritanica skin melanophores are able to activate a process of colour change autonomously. This study yields the first evidence of crypsis mediated by dermal light sensitivity in amniote
The GAPS Programme with HARPS-N at TNG VIII: Observations of the Rossiter-McLaughlin effect and characterisation of the transiting planetary systems HAT-P-36 and WASP-11/HAT-P-10
We determine the true and the projected obliquity of HAT-P-36 and
WASP-11/HAT-P-10 systems, respectively, which are both composed of a relatively
cool star and a hot-Jupiter planet. Thanks to the high-resolution spectrograph
HARPS-N, we observed the Rossiter-McLaughlin effect for both the systems by
acquiring precise radial-velocity measurements during planetary transit events.
We also present photometric observations comprising six light curves covering
five transit events, obtained using three medium-class telescopes and the
telescope-defocussing technique. One transit of WASP-11/HAT-P-10 was followed
simultaneously from two observatories. The three transit light curves of
HAT-P-36b show anomalies that are attributable to starspot complexes on the
surface of the parent star, in agreement with the analysis of its spectra that
indicate a moderate activity. By analysing the complete HATNet data set of
HAT-P-36, we estimated the stellar rotation period by detecting a periodic
photometric modulation in the light curve caused by star spots, obtaining
Prot=15.3 days, which implies that the inclination of the stellar rotational
axis with respect to the line of sight is 65 degree. We used the new
spectroscopic and photometric data to revise the main physical parameters and
measure the sky-projected misalignment angle of the two systems. We found
\lambda=-14 degree for HAT-P-36 and \lambda=7 degree for WASP-11/HAT-P-10,
indicating in both cases a good spin-orbit alignment. In the case of HAT-P-36,
we also measured its real obliquity, which turned out to be 25 degrees.Comment: 18 pages, 14 figure
The deep-sea hub of the ANTARES neutrino telescope
The ANTARES neutrino telescope, currently under construction at 2500 m depth off the French Mediterranean coast, will contain 12 detection lines, powered and read out through a deep-sea junction box (JB) hub. Electrical energy from the shore station is distributed through a transformer with multiple secondary windings and a plugboard with 16 deep sea-mateable electro-optic connectors. Connections are made to the JB outputs using manned or remotely operated submersible vehicles. The triply redundant power management and slow control system is based on two identical AC-powered systems, communicating with the shore through 160 Mb/s fibre G-links and a third battery-powered system using a slower link. We describe the power and slow control systems of the underwater hub
Selective inhibition of genomic and non-genomic effects of thyroid hormone regulates muscle cell differentiation and metabolic behavior
Thyroid hormones (THs) are key regulators of different biological processes. Their action involves genomic and non-genomic mechanisms, which together mediate the final effects of TH in target tissues. However, the proportion of the two processes and their contribution to the TH-mediated effects are still poorly understood. Skeletal muscle is a classical target tissue for TH, which regulates muscle strength and contraction, as well as energetic metabolism of myofibers. Here we address the different contribution of genomic and non-genomic action of TH in skeletal muscle cells by specifically silencing the deiodinase Dio2 or the β3-Integrin expression via CRISPR/Cas9 technology. We found that myoblast proliferation is inversely regulated by integrin signal and the D2-dependent TH activation. Similarly, inhibition of the nuclear receptor action reduced myoblast proliferation, confirming that genomic action of TH attenuates proliferative rates. Contrarily, genomic and non-genomic signals promote muscle differentiation and the regulation of the redox state. Taken together, our data reveal that integration of genomic and non-genomic signal pathways finely regulates skeletal muscle physiology. These findings not only contribute to the understanding of the mechanisms involved in TH modulation of muscle physiology but also add insight into the interplay between different mechanisms of action of TH in muscle cells
Impact de l'introduction des légumineuses dans les systèmes de culture sur les émissions de protoxyde d'azote
Dans un objectif d'atténuation du réchauffement climatique, la mise en place de systèmes de culture plus autonomes vis - à - vis des engrais minéraux devient incontournable pour réduire les émissions de gaz à effet de serre (GES) tout en diminuant le coût de la fertilisation. L'insertion de légumineuses dans ces systèmes semble être un levier prometteur pour y parvenir. Les économies d'azote permises par différents modes d'introduction de légumineuses et leur impact sur les émissions de GES ont été estimés et évalués en quantifiant au préalable les flux d'azote dans les systèmes avec ou sans légumineuses à partir de données issues de dispositifs expérimentaux préexistants, disponibles dans la bibliographie ou acquises dans de nouveaux essais. L'introduction de légumineuses présente régulièrement un impact positif sur la réduction de l'emploi des engrais azotés. Le risque d'augmentation de la lixiviation du nitrate dépend de leur mode d'introduction et de leur place dans les rotations. Enfin, les émissions mesurées en cul tures principales de légumineuses sont généralement très significativement réduites en comparaison des cultures fertilisées, cependant la dégradation des résidus des légumineuses (en culture ou en couverts) peut générer des émissions de N 2 O corrélées à leur impact sur les flux d'azote, variable selon les conditions pédoclimatiques. Ces résultats devraient permettre d'élaborer des recommandations pour mieux prendre en compte les légumineuses dans la conception de systèmes de culture plus autonomes vis - à - vis des engrais azotés de synthèse et moins émetteurs de N 2 0
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