Comparing the Currents Measured by CARTHE, CODE and SVP Drifters as a Function of Wind and Wave Conditions in the Southwestern Mediterranean Sea

Instruments drifting at the ocean surface are quasi-Lagrangian, that is, they do not follow exactly the near-surface ocean currents. The currents measured by three commonly-used drifters (CARTHE, CODE and SVP) are compared in a wide range of sea state conditions (winds up to 17 m/s and significant wave height up to 3 m). Nearly collocated and simultaneous drifter measurements in the southwestern Mediterranean reveal that the CARTHE and CODE drifters measure the currents in the first meter below the surface in approximately the same way. When compared to SVP drogued at 15 m nominal depth, the CODE and CARTHE currents are essentially downwind (and down-wave), with a typical speed of 0.5–1% of the wind speed. However, there is a large scatter in velocity differences between CODE/CARTHE and SVP for all wind and sea state conditions encountered, principally due to vertical and horizontal shears not related to the wind. For the CODE drifter with wind speed larger than 10 m/s and significant wave height larger than 1 m, about 30–40% of this difference can be explained by Stokes drift.

The molecular identity of the characean OH− transporter: a candidate related to the SLC4 family of animal pH regulators

Characeae are closely related to the ancient algal ancestors of all land plants. The long characean cells display a pH banding pattern to facilitate inorganic carbon import in the acid zones for photosynthetic efficiency. The excess OH−, generated in the cytoplasm after CO2 is taken into the chloroplasts, is disposed of in the alkaline band. To identify the transporter responsible, we searched the Chara australis transcriptome for homologues of mouse Slc4a11, which functions as OH−/H+ transporter. We found a single Slc4-like sequence CL5060.2 (named CaSLOT). When CaSLOT was expressed in Xenopus oocytes, an increase in membrane conductance and hyperpolarization of resting potential difference (PD) was observed with external pH increase to 9.5. These features recall the behavior of Slc4a11 in oocytes and are consistent with the action of a pH-dependent OH−/H+ conductance. The large scatter in the data might reflect intrinsic variability of CaSLOT transporter activation, inefficient expression in the oocyte due to evolutionary distance between ancient algae and frogs, or absence of putative activating factor present in Chara cytoplasm. CaSLOT homologues were found in chlorophyte and charophyte algae, but surprisingly not in related charophytes Zygnematophyceae or Coleochaetophyceae.

Statistical analysis of thermal conductivity experimentally measured in water-based nanofluids

Nanofluids are suspensions of nanoparticles in a base heat-transfer liquid. They have been widely investigated to boost heat transfer since they were proposed in the 1990s. We present a statistical correlation analysis of experimentally measured thermal conductivity of water-based nanofluids available in the literature. The influences of particle concentration, particle size, temperature and surfactants are investigated. For specific particle materials (alumina, titania, copper oxide, copper, silica and silicon carbide), separate analyses are performed. The conductivity increases with the concentration in qualitative agreement with Maxwell’s theory of homogeneous media. The conductivity also increases with the temperature (in addition to the improvement due to the increased conductivity of water). Surprisingly, only silica nanofluids exhibit a statistically significant effect of the particle size, whereby smaller particles lead to faster heat transfer. Overall, the large scatter in the experimental data prevents a compelling, unambiguous assessment of these effects. Taken together, the results of our analysis suggest that more comprehensive experimental characterizations of nanofluids are necessary to estimate their practical potential.

Late Pleistocene ice field on Jakupica Mt. (North Macedonia): extent and timing glaciation

<p>Since the 19<sup>th</sup> century, geomorphological studies in the currently mainly unglaciated central Balkan Peninsula described extended glacial landforms and repeated glaciations. With the growing number of numerical ages an ambiguous picture has formed concerning the timing of the most extended glaciation and also on the glacier response to the cooling phases (e.g. Younger Dryas) during the last deglaciation of these mountain ranges.</p><p>This study provides <sup>10</sup>Be cosmic ray exposure ages of a succession of glacial landforms in the Jakupica Mt. (North Macedonia), aiming to improve the understanding of Late Pleistocene glacier development in the area [1].</p><p>In the Jakupica Mt. (~41.7° N, ~21.4 E; Solunska Glava, 2540 m asl) a large plateau glacier was reconstructed (max. area ~45 km<sup>2</sup>, max thickness: ~300 m), where three main ice accumulation areas could be delineated [2]. The study area comprises six northeastward facing, formerly glaciated valleys. Two of these valleys emerge from the plateau, one stands separate, and the remaining three are topographically separated by a relatively flat NNW-SSE oriented ridge. During the most extensive glacial stages, these three valleys were fed by ice overflowing above this ridge from the plateau. The lowest mapped moraines are descending down to 1550-1700 m asl suggesting the former existence of glacier tongues of ~3 km length. The large plateau ice and the complicated system of confluences makes glacier reconstructions and equilibrium line altitude (ELA) calculations challenging. Thus, the ELAs were preliminary estimated based on the maximum elevation of the lowermost lateral moraines, leading to ELA values of 1800±50 m a.s.l. for the most extended phase.</p><p>The maximum ice extent outlined by the lowest mapped moraines descending down to 1550-1500 m asl. occurred around ~24-19 ka (n=5), in agreement with the timing of the Last Glacial Maximum. During the Lateglacial, the exposure ages are getting younger by the glacier recession up to the moraines at ~1820 m asl (~19-14 ka, n=15). However, the highest sampled landforms (~2200 m asl) provided ages with a large scatter between ~25 and ~5 ka (n=6). This large scatter and the observed bias towards old ages are most probably the result of inherited cosmogenic nuclide concentrations within the rock. Consequently, <sup>10</sup>Be exposure ages alone are apparently not suitable to determine the age of final deglaciation of this mountain. Similar conditions have been observed in the Retezat Mts (Southern Carpathians, Romania) [3].</p><p>This research was supported by the NKFIH FK124807 and GINOP-2.3.2-15-2016-00009 projects and by the Radiate Transnational Access 19001688-ST.</p><p>[1] Ruszkiczay-Rüdiger et al., 2020. Last deglaciation in the central Balkan Peninsula: Geochronological evidence from Jablanica Mt. (North Macedonia). Geomorphology 351: 106985</p><p>[2] Temovski et al., 2019. Glacial geomorphology of the northeastern part of the Jakupica Mountain, Macedonia, Central Balkan Peninsula. GRA 21, EGU2019-7822</p><p>[3] Ruszkiczay-Rüdiger et al., 2018. Glacier reconstruction, deglaciation chronology and paleo-environment reconstruction, Retezat Mountains, Southern Carpathians, Romania. Geologica Balcanica; Abstracts of the XXI. CBGA Congress, Salzburg, 10-13 September; p. 240-241.</p>

On the origin of nitrogen at low metallicity

ABSTRACT Understanding the evolution of the N/O ratio in the interstellar medium (ISM) of galaxies is essential if we are to complete our picture of the chemical evolution of galaxies at high redshift, since most observational calibrations of O/H implicitly depend upon the intrinsic N/O ratio. The observed N/O ratio, however, shows large scatter at low O/H, and is strongly dependent on galactic environment. We show that several heretofore unexplained features of the N/O distribution at low O/H can be explained by the N seen in metal-poor galaxies being mostly primary nitrogen that is returned to the ISM via pre-supernova winds from rapidly rotating massive stars (M ≳ 10 M⊙, v/vcrit ≳ 0.4). This mechanism naturally produces the observed N/O plateau at low O/H. We show that the large scatter in N/O at low O/H also arises naturally from variations in star-formation efficiency. By contrast, models in which the N and O come primarily from supernovae provide a very poor fit to the observed abundance distribution. We propose that the peculiar abundance patterns we observe at low O/H are a signature that dwarf galaxies retain little of their SN ejecta, leaving them with abundance patterns typical of winds.

Major aspects of working-age population disability caused by mental disorders

The scientific review reveals the relevance of the problem of persistent disability in patients with mental disorders as one of the most important indicators of public health. It has been shown that organic pathology plays an important role in increasing of incidence of disability due to mental disorders in people of working age. In addition, the clinical and epidemiological data of recent years, confirming the large scatter of disability rates across regions and the poorly understood clinical factors that determine disability in organic mental disorders, are presented. The need for further study of predictors of health deterioration as well as risk factors for persistent disability in order to solve the problems of preventing disability and to develop personalized programs of medical and social rehabilitation is discussed.

Strain Localizations in Notches for a Coarse-Grained Ni-Based Superalloy: Simulations and Experiments

Alloys used for turbine blades have to safely sustain severe thermomechanical loadings during service such as, for example, centrifugal loadings, creep and high temperature gradients. For these applications, cast Ni-based superalloys characterized by a coarse-grained microstructure are widely adopted. This microstructure dictates a strong anisotropic mechanical behaviour and, concurrently, a large scatter in the fatigue properties is observed. In this work, Crystal Plasticity Finite Element (CPFE) simulations and strain measurements performed by means of Digital Image Correlations (DIC) were adopted to study the variability introduced by the coarse-grained microstructure. In particular, the CPFE simulations were calibrated and used to simulate the effect of the grain cluster orientations in proximity to notches, which reproduce the cooling air ducts of the turbine blades. The numerical simulations were experimentally validated by the DIC measurements. This study aims to predict the statistical variability of the strain concentration factors and support component design.

Prediction of California Bearing Ratio and compaction characteristics of Transvaal soils from indicator properties

ABSTRACT A preliminary statistical analysis of 914 mostly Transvaal soils of average selected subgrade quality produced useful, highly statistically significant methods for the prediction of the maximum Proctor CBR and the Proctor compaction characteristics, as well as relationships between soaked and unsoaked CBR and between Proctor and MAASHO compaction characteristics. Because of the well-known poor reproducibilty of the CBR, as well as the indicator tests used, it is believed that the accuracy of the prediction methods is better than it appears from the large scatter of results. These methods do not replace CBR testing but supplement it by possibly reducing the number of expensive tests and providing a check on gross errors. Keywords: CBR, prediction, indicator tests, subgrade, Proctor

Homogeneity in the early chemical evolution of the Sextans dwarf spheroidal galaxy

We present the high-resolution spectroscopic analysis of two new extremely metal-poor star (EMPS) candidates in the dwarf spheroidal galaxy Sextans. These targets were preselected from medium-resolution spectra centered around the Ca II triplet in the near-infrared and were followed-up at higher resolution with VLT/UVES. We confirm their low metallicities with [Fe/H] = −2.95 and [Fe/H] = −3.01, which place them among the most metal-poor stars known in Sextans. The abundances of 18 elements, including C, Na, the α, Fe-peak, and neutron-capture elements, are determined. In particular, we present the first unambiguous detection of Zn in a classical dwarf at extremely low metallicity. Previous indications were made of a large scatter in the abundance ratios of the Sextans stellar population around [Fe/H] ∼ − 3 when compared to other galaxies, particularly with very low observed [α/Fe] ratios. We took the opportunity of reanalyzing the full sample of EMPS in Sextans and find a [α/Fe] Milky Way-like plateau and a ∼0.2 dex dispersion at fixed metallicity.

A comparative study of satellite galaxies in Milky Way-like galaxies from HSC, DECaLS, and SDSS

ABSTRACT We conduct a comprehensive and statistical study of the luminosity functions (LFs) for satellite galaxies, by counting photometric galaxies from HSC, DECaLS, and SDSS around isolated central galaxies (ICGs) and paired galaxies from the SDSS/DR7 spectroscopic sample. Results of different surveys show very good agreement. The satellite LFs can be measured down to MV ∼ −10, and for central primary galaxies as small as 8.5 < log10M*/M⊙ < 9.2 and 9.2 < log10M*/M⊙ < 9.9, which implies there are on average 3–8 satellites with MV < −10 around LMC-mass ICGs. The bright end cutoff of satellite LFs and the satellite abundance are both sensitive to the magnitude gap between the primary and its companions, indicating galaxy systems with larger magnitude gaps are on average hosted by less massive dark matter haloes. By selecting primaries with stellar mass similar to our Milky Way (MW), we discovered that (i) the averaged satellite LFs of ICGs with different magnitude gaps to their companions and of galaxy pairs with different colour or colour combinations all show steeper slopes than the MW satellite LF; (ii) there are on average more satellites with −15 < MV < −10 than those in our MW; (iii) there are on average 1.5 to 2.5 satellites with MV < −16 around ICGs, consistent with our MW; (iv) even after accounting for the large scatter predicted by numerical simulations, the MW satellite LF is uncommon at MV > −12. Hence, the MW and its satellite system are statistically atypical of our sample of MW-mass systems. In consequence, our MW is not a good representative of other MW-mass galaxies. Strong cosmological implications based on only MW satellites await additional discoveries of fainter satellites in extra-galactic systems. Interestingly, the MW satellite LF is typical among other MW-mass systems within 40 Mpc in the local Universe, perhaps implying the Local Volume is an underdense region.