Modeling sea level changes and geodetic variations by glacial isostasy: the improved SELEN code

We describe the basic features of SELEN, an open source Fortran 90 program for the numerical solution of the so-called "Sea Level Equation" for a spherical, layered, non-rotating Earth with Maxwell viscoelastic rheology. The Sea Level Equation was introduced in the 70s to model the sea level variations in response to the melting of late-Pleistocene ice-sheets, but it can be also employed for predictions of geodetic quantities such as vertical and horizontal surface displacements and gravity variations on a global and a regional scale. SELEN (acronym of SEa Level EquatioN solver) is particularly oriented to scientists at their first approach to the glacial isostatic adjustment problem and, according to our experience, it can be successfully used in teaching. The current release (2.9) considerably improves the previous versions of the code in terms of computational efficiency, portability and versatility. In this paper we describe the essentials of the theory behind the Sea Level Equation, the purposes of SELEN and its implementation, and we provide practical guidelines for the use of the program. Various examples showing how SELEN can be configured to solve geodynamical problems involving past and present sea level changes and current geodetic variations are also presented and discussed

SELEN 4 (SELEN version 4.0): a Fortran program for solving the gravitationally and topographically self-consistent sea-level equation in glacial isostatic adjustment modeling

Abstract. We present SELEN4 (SealEveL EquatioN solver), an open-source program written in Fortran 90 that simulates the glacial isostatic adjustment (GIA) process in response to the melting of the Late Pleistocene ice sheets. Using a pseudo-spectral approach complemented by a spatial discretization on an icosahedron-based spherical geodesic grid, SELEN4 solves a generalized sea-level equation (SLE) for a spherically symmetric Earth with linear viscoelastic rheology, taking the migration of the shorelines and the rotational feedback on sea level into account. The approach is gravitationally and topographically self-consistent, since it considers the gravitational interactions between the solid Earth, the cryosphere, and the oceans, and it accounts for the evolution of the Earth's topography in response to changes in sea level. The SELEN4 program can be employed to study a broad range of geophysical effects of GIA, including past relative sea-level variations induced by the melting of the Late Pleistocene ice sheets, the time evolution of paleogeography and of the ocean function since the Last Glacial Maximum, the history of the Earth's rotational variations, present-day geodetic signals observed by Global Navigation Satellite Systems, and gravity field variations detected by satellite gravity missions like GRACE (the Gravity Recovery and Climate Experiment). The "GIA fingerprints" constitute a standard output of SELEN4. Along with the source code, we provide a supplementary document with a full account of the theory, some numerical results obtained from a standard run, and a user guide. Originally, the SELEN program was conceived by Giorgio Spada (GS) in 2005 as a tool for students eager to learn about GIA, and it has been the first SLE solver made available to the community

Relationship between the moment of inertia and the k2k_2 Love number of fluid extra-solar planets

Context: Tidal and rotational deformation of fluid giant extra-solar planets may impact their transit light curves, making the $k_2$ Love number observable in the upcoming years. Studying the sensitivity of $k_2$ to mass concentration at depth is thus expected to provide new constraints on the internal structure of gaseous extra-solar planets. Aims: We investigate the link between the mean polar moment of inertia $N$ of a fluid, stably layered extra-solar planet and its $k_2$ Love number, aiming at obtaining analytical relationships valid, at least, for some particular ranges of the model parameters. We also seek a general, approximate relationship useful to constrain $N$ once observations of $k_2$ will become available. Methods: For two-layer fluid extra-solar planets, we explore the relationship between $N$ and $k_2$ by analytical methods, for particular values of the model parameters. We also explore approximate relationships valid over all the possible range of two-layer models. More complex planetary structures are investigated by the semi-analytical propagator technique. Results: A unique relationship between $N$ and $k_2$ cannot be established. However, our numerical experiments show that a `rule of thumb' can be inferred, valid for complex, randomly layered stable planetary structures. The rule robustly defines the upper limit to the values of $N$ for a given $k_2$, and agrees with analytical results for a polytrope of index one and with a realistic non-rotating model of the tidal equilibrium of Jupiter.Comment: Accepted for publication on Astronomy & Astrophysic

The textile materiality in the graduation of the fashion designer

AThe text presents a methodological experience lived in a Fashion Design course in the city of Rio de Janeiro, Brazil, made with students from the last semester during the development of their conclusion projects. It presents the study of a tool for the creative process and some results obtained. The text also reflects on the importance of textile material as a creative element and not just as a means for clothing

Would the combination of everolimus with endocrine-therapy help in FGFR2 positive serous endometrial cancer?

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Palaeo-Shoreline Configuration of the Adventure Plateau (Sicilian Channel) at the Last Glacial Maximum

The Adventure Plateau, located in the NW sector of the Sicilian Channel, experienced several episodes of exposure/erosion and subsequent drowning, with the most recent occurring after the Last Glacial Maximum (LGM). Unlike other parts of the Sicilian Channel, the Adventure Plateau is relatively tectonically stable and is therefore best suitable for reconstructing its coastal configuration before the post-LGM marine transgression. Here, we use high-resolution seismic data to identify and map the palaeo-coastline at the LGM on the basis of the internal architecture of the prograding wedges (i.e., the location of the subaqueous clinoform rollover point) and the erosional markers such as the subaerial unconformities and the wave ravinement surfaces. These data, which show an extreme variability in the palaeo-morphology of the coastal margins of the Adventure Plateau, have been complemented with vintage seismic profiles in order to entirely cover its perimeter. The mapped LGM coastline has then been compared to predictions from glacial isostatic adjustment (GIA) modeling, which considers the horizontal migration of the shorelines in response to sea level rise and to Earth's rotational and deformational effects associated with deglaciation. The two shorelines (i.e., the coastline derived from the marine data interpretation and the one derived from the GIA model) are in good agreement at 21 kyears BP, although some discrepancies occur in the southern part of the plateau, where the seabed slope is extremely gentle, which makes the clinoform rollover points and the buried erosional unconformities difficult to detect. After 20 kyears BP, an acceleration in the rate of the sea level rise occurred. The results of this study indicate the importance of comparing experimental data with model predictions in order to refine and calibrate boundary parameters and to gain a better picture of the evolution of sea level rise over various time scales

Physico-Chemical Features of Undoped and Fe/Cu-Doped Na0.67MnO2-Layered Cathodes for Sodium Batteries

Na0.67MnO2 (NMO) stands out among the layered cathode materials used for sodium batteries due to its high-capacity values, low cost, and environmental friendliness. Unfortunately, many drawbacks arise during cycling, but nanostructure tailoring and doping can help to mitigate them. Our aim was to synthesize undoped and Cu- or Fe-doped NMO samples via the sol-gel route, with a different cooling step to room temperature, i.e., in a natural way or via quenching. The formation of a mixture of polymorphs was observed, as well as differences in the external morphology of the powders' grains. The use of spectroscopic techniques, Mössbauer spectroscopy for the Fe-doped samples and Electron paramagnetic resonance, allowed us to gain insights into the oxidation states of transition metals and to make suggestions about the magnetic ordering, as well as on the possible presence of magnetic impurities. Cyclic voltammetry and galvanostatic cycling results were interpreted on the basis of the spectroscopic data: the introduction of substituents, in general, worsens the capacity values, due to the decrease in the P2 amount and the introduction of structural distortions. The structural stability of the samples in air as a function of time was also analyzed via X-ray diffraction, demonstrating the positive effect of Cu presence

Association between EEG Paroxysmal Abnormalities and Levels of Plasma Amino Acids and Urinary Organic Acids in Children with Autism Spectrum Disorder

Abnormalities in the plasma amino acid and/or urinary organic acid profile have been reported in autism spectrum disorder (ASD). An imbalance between excitatory and inhibitory neuronal activity has been proposed as a mechanism to explain dysfunctional brain networks in ASD, as also suggested by the increased risk of epilepsy in this disorder. This study explored the possible association between presence of EEG paroxysmal abnormalities and the metabolic profile of plasma amino acids and urinary organic acids in children with ASD. In a sample of 55 children with ASD (81.8% male, mean age 53.67 months), EEGs were recorded, and 24 plasma amino acids and 56 urinary organic acids analyzed. EEG epileptiform discharges were found in 36 (65%) children. A LASSO regression, adjusted by age and sex, was applied to evaluate the association of plasma amino acids and urinary organic acids profiles with the presence of EEG epileptiform discharges. Plasma levels of threonine (THR) (coefficient = −0.02, p = 0.04) and urinary concentration of 3-Hydroxy-3-Methylglutaric acid (HMGA) (coefficient = 0.04, p = 0.02) were found to be associated with the presence of epileptiform discharges. These results suggest that altered redox mechanisms might be linked to epileptiform brain activity in ASD

The mid-Holocene sea-level change in the Arabian Gulf

The mid-Holocene sea-level highstand is a well-known phenomenon in sea-level science, yet the knowledge on the highstand’s spatial and temporal distribution remains incomplete. Here we study the southwest coast of the Arabian-Persian Gulf where a mid-Holocene sea-level highstand and subsequent sea-level fall may have occurred due to the Earth crustal response to meltwater load. Sea-level indicators were established using standard facies analysis and error calculations, then constrained through glacio-isostatic adjustment (GIA) modelling and though procedures based on Gaussian Process and exponential decay analysis. This work allowed to identify the highstand at 1.6 ± 0.4 m occurring 6.7–6.0 ka, in excellent agreement with GIA model results. The subsequent shoreline migration followed the geophysical constraint by prograding in line with the sea-level fall until around 3 ka. Then, the strength of the external control weakened and internal processes, in particular sediment binding through microbial activity, started controlling the geometry of the accommodation space. </jats:p