Nonlinear diffusion & thermo-electric coupling in a two-variable model of cardiac action potential

This work reports the results of the theoretical investigation of nonlinear dynamics and spiral wave breakup in a generalized two-variable model of cardiac action potential accounting for thermo-electric coupling and diffusion nonlinearities. As customary in excitable media, the common Q10 and Moore factors are used to describe thermo-electric feedback in a 10-degrees range. Motivated by the porous nature of the cardiac tissue, in this study we also propose a nonlinear Fickian flux formulated by Taylor expanding the voltage dependent diffusion coefficient up to quadratic terms. A fine tuning of the diffusive parameters is performed a priori to match the conduction velocity of the equivalent cable model. The resulting combined effects are then studied by numerically simulating different stimulation protocols on a one-dimensional cable. Model features are compared in terms of action potential morphology, restitution curves, frequency spectra and spatio-temporal phase differences. Two-dimensional long-run simulations are finally performed to characterize spiral breakup during sustained fibrillation at different thermal states. Temperature and nonlinear diffusion effects are found to impact the repolarization phase of the action potential wave with non-monotone patterns and to increase the propensity of arrhythmogenesis

Vitamin D status of inmates. The experience of penitentiaries prisons in the province of Salerno in Southern Italy

Introduction: Prisoners are at risk of developing vitamin D deficiency due to their lacking exposure to sunlight. So far, there are no published studies evaluating blood levels of vitamin D in relation to the health status of inmates and the quality of the Italian prison system. Aim: To investigate vitamin D status and its determinants in a cohort of prisoners. Subject and methods: One hundred and seventy-two (172) pri-son inmates (males, n=159, age 47± 11.3 years; females, n=13, age 43.91±12.18 years) of three penitentiaries in the province of Salerno. Vitamin D deficiency, insufficiency and sufficiency were respectively defined as a 25(OH)D level <20 ng/mL; from 20 to 30 ng/mL, >30 ng/mL. Results: In our group, Vitamin D deficiency occurs in 77.32% of the prisoners with 32.55% of the cases having severe insufficiency. Prisoners with higher BMI show lower circulating vitamin D levels (p<0.001). No significant relationship was found with the duration of detention (Pearson R: 0.01). Conclusion: In this cohort of inmates the vitamin D status is determined by BMI, but not by the duration of the detention

Síndrome caída del ganado: consideraciones experimentales con base en plantas acumuladoras de nitratos.

Se busca evidenciar la posible relación existente entre los nitratos contenidos en algunas plantas nativas de los departamentos de Córdoba y Sucre, en Colombia, con el desenlace del síndrome caída del ganado. Se administra oralmente la mezcla de 4 plantas que acumularon elevados niveles de nitratos en la época de iniciación de lluvias: cansaviejo (Mascagnia concinna), bacota (Anemopaegma orbiculatum), yerba de pajarito (Sarcostemma glaucun) y cotorrera (sin clasificación taxonómica). El pasto admirable (Brachiaria mutica) se utiliza como control en los ensayos. Se utilizan 6 novillos de la raza Costeño con Cuernos x Cebú. Se efectúan 2 ensayos experimentales, dividiendo los animales en 2 grupos: problema y control. Cada ensayo duró 72 horas. Al grupo problema se le suministra como forraje una mezcla a partes iguales de las 4 plantas acumuladoras de nitratos, en cantidad equivalente al 10 por ciento del peso total de los animales. El grupo control se alimenta con pasto admirable en cantidad equivalente al 10 por ciento del peso total de los animales. Transcurrida una semana, se alternan los grupos para efectuar el experimento 2. En el primer ensayo los niveles de metahemoglobina no mostraron un incremento significativo entre los animales pertenecientes a cada grupo, sin embargo, las frecuencias respiratoria y cardíaca tuvieron diferencias altamente significativas entre los 2 tratamientos. En el segundo ensayo se observan diferencias altamente significativas en los niveles de metahemoglobina y en frecuencias respiratoria y cardíaca entre los 2 grupos Por lo anterior se considera que la caída del ganado no tiene una etiología específica definida, sino que es el resultado de una concomitancia de factores de diversa índoleGanado de doble propósito-Ganaderia doble proposit

The new Checklist of the Italian Fauna: marine Mollusca.

The mollusc fauna of the Mediterranean Sea is still considered as the best-known marine mollusc fauna in the world. The previous modern checklists of marine Mollusca were produced by joint teams of amateurs and professionals. During the last years the Italian Society of Malacology (Società Italiana di Malacologia – S.I.M.) maintained an updated version of the Mediterranean checklist, that served as the backbone for the development of the new Italian checklist. According to the current version (updated on April 1st, 2021), 1,777 recognised species of marine molluscs are present in the Italian Economic Exclusive Zone, including also the Tyrrhenian coasts of Corsica and the continental shelf of the Maltese archipelago. The new checklist shows an increase of 17% of the species reported in the 1995 Checklist. This is largely (yet not solely) due to the new wave of studies based on Integrative Taxonomy approaches. A total of 135 species (7.6%) are strictly endemic to the Italian waters; 44 species (2.5%) are alien and correspond to the 28% of the Mediterranean alien marine molluscs. All eight extant molluscan classes are represented. The families represented in the Italian fauna are 307, an increase of 14.6% from the first checklist, partly due to new records and partly to new phylogenetic systematics. Compared with the whole Mediterranean malacofauna, the Italian component represents 71% in species and 61% in families, which makes it a very remarkable part of the Mediterranean fauna

Murge and Pre-murge in southern Italy: the last piece of Adria, the (almost) lost continent, attempting to became an aUGGp candidate (MurGEOpark)

In 2019, the executive of the Alta Murgia National Park (southeastern Italy) decided to propose its territory as possible inclusion in the network of the UNESCO Global Geoparks. Since then, in cooperation with the Department of Earth and Environmental Sciences (Aldo Moro University of Bari) and SIGEA, it is working to candidate the area as an aUGGp (called “MurGEOpark”). The MurGEOpark comprises the Alta Murgia area, where a Cretaceous sector of the Apulia Carbonate Platform crops out, and the adjacent Pre-Murge area, where the southwestward lateral continuation of the same platform, being flexed toward the southern Apennines mountain chain, is thinly covered by Plio-Quaternary foredeep deposits. The worldwide geological uniqueness is that the area is the only in situ remnant of the AdriaPlate, the old continent almost entirely squeezed between Africa and Europe. In such a contest, AltaMurgia is a virtually undeformed sector of Adria (the Apulia Foreland), while other territories of theplate are, and/or were, involved in the subduction/collision processes. In the MurGEOpark, the crustof Adria is still rooted to its mantle, and the Cretaceous evolution of the continent is spectacularlyrecorded in Alta Murgia thanks to the limestone succession of one of the largest peri-Tethyancarbonate platform (the Apulia Carbonate Platform). The MurGEOpark comprises also the Pre-Murge area, which represents the outer south-Apennines foredeep, whose Plio-Quaternaryevolution is spectacularly exposed thanks to an “anomalous” regional middle-late Quaternary uplift.The international value of the proposal is enriched by the presence of several geological singularities such as two paleontological jewels of very different age: a Neanderthal skeletonpreserved in speleothems within a karst cave, and one of the largest surfaces in the world withupper Cretaceous dinosaur tracks (about 25.000 footprints). Moreover, the close relationships between man and geology are spectacularly documented in the MurGEOpark: among the others, the use and conservation of water in a karst area, the prehistoric and ancestral choices ofurbanization, karst caves traditionally used as religious sites, etc. All these examples demonstratehow the MurGEOpark could offer a good opportunity to spread the geological culture to a wide and diverse audienc

The exceptionally extended flaring activity in the X-ray afterglow of GRB 050730 observed with Swift and XMM-Newton

We present the results of a detailed spectral and temporal analysis of Swift and XMM-Newton observations of the high redshift (z=3.969) GRB 050730. The X-ray afterglow of GRB 050730 was found to decline with time with superimposed intense flaring activity that extended over more than two orders of magnitude in time. Seven distinct re-brightening events starting from 236 s up to 41.2 ks after the burst were observed. The underlying decay of the afterglow was well described by a double broken power-law model with breaks at t_1= 237 +/- 20 s and t_2 = 10.1 (-2.2) (+4.6) ks. The temporal decay slopes before, between and after these breaks were alpha_1 = 2.1 +/- 0.3, alpha_2 = 0.44 (-0.08) (+0.14) and alpha_3 = 2.40 (+0.07) (-0.09), respectively. The spectrum of the X-ray afterglow was well described by a photoelectrically absorbed power-law with an absorbing column density N_H=(1.28 +/- 0.26) 10^22 cm^-2 in the host galaxy. Strong X-ray spectral evolution during the flaring activity was present. In the majority of the flares (6/7) the ratio Delta_t/t_p between the duration of the event and the time when the flare peaks was nearly constant and about 0.6-0.7. We showed that the observed spectral and temporal properties of the first three flares are consistent with being due both to high-latitude emission, as expected if the flares were produced by late internal shocks, or to refreshed shocks, i.e. late time energy injections into the main afterglow shock by slow moving shells ejected from the central engine during the prompt phase. The event fully satisfies the E_p-E_iso Amati relation while is not consistent with the E_p-E_jet Ghirlanda relation.Comment: 12 pages, 5 figures, accepted for publication in A&

Integrin Beta 1 Is Crucial for Urinary Concentrating Ability and Renal Medulla Architecture in Adult Mice

Integrins are heterodimers anchoring cells to the surrounding extracellular matrix (ECM), an active and complex process mediating a series of inside-out and outside-in stimuli regulating cellular turn-over, tissue growth and architecture. Itgb1 is the main subunit of the renal integrins and it is critical for renal development. This study aims to investigate the role of Itgb1 in the adult renal epithelial cells by knocking down Itgb1 in PAX8 expressing cells. Itgb1-Pax8 cKO mice develop a progressively worsening proteinuria and renal abnormalities leading to severe renal failure and hypertension. This phenotype is also associated with severe dysfunction of distal nephron and polyuria. To further investigate whether distal nephron involvement was primarily related to Itgb1 suppression or secondary to renal failure, an Itgb1-AQP2 cKO mouse model was generated. These mice lack Itgb1 expression in AQP2 expressing cells. They do not show any developmental alteration, but 1 month old mice are resistant to dDAVP administration and finally, at 2 months of age, they develop overt polyuria. This phenotype is due to primary collecting duct (CD) cells anoikis. The entire architecture of the outer medulla is altered, with loss of the typical organization pattern of vascular and tubular bundles alternation. Indeed, even though not primarily affected by genetic ablation, the TAL is secondarily affected in this model. It is sufficient to suppress Itgb1 expression in the CD in order to stimulate proliferation and then disappearance of neighboring TAL cells. This study shows that cell to cell interaction through the ECM is critical for architecture and function maintenance of the outer medulla and that Itgb1 is crucial for this process

Supermassive Black Hole Winds in X-rays: SUBWAYS: I. Ultra-fast outflows in quasars beyond the local Universe

We present a new X-ray spectroscopic study of 22 luminous (2 × 1045 ≲ Lbol/erg s-1 ≲ 2 × 1046) active galactic nuclei (AGNs) at intermediate redshifts (0.1 ≲ z ≲ 0.4), as part of the SUpermassive Black hole Winds in the x-rAYS (SUBWAYS) sample, mostly composed of quasars and type 1 AGNs. Here, 17 targets were observed with XMM-Newton in 2019- 2020, and the remaining 5 are from previous observations. The aim of this large campaign (1.45 Ms duration) is to characterise the various manifestations of winds in the X-rays driven from supermassive black holes in AGNs. In this paper we focus on the search for and characterisation of ultra-fast outflows (UFOs), which are typically detected through blueshifted absorption troughs in the Fe K band (E > 7 keV). By following Monte Carlo procedures, we confirm the detection of absorption lines corresponding to highly ionised iron (e.g. Fe XXV Hα and Fe XXVI Lyα) in 7 out of 22 sources at the ≳95% confidence level (for each individual line). The global combined probability of such absorption features in the sample is > 99.9%. The SUBWAYS campaign, based on XMM-Newton, extends to higher luminosities and redshifts than previous local studies on Seyferts. We find a UFO detection fraction of ∼30% of the total sample, which is in agreement with previous findings. This work independently provides further support for the existence of highly ionised matter propagating at mildly relativistic speeds (≳0.1c) in a considerable fraction of AGNs over a broad range of luminosities, which is believed to play a key role in the self-regulated AGN feeding-feedback cycle, as also supported by hydrodynamical multi-phase simulations