Propagation and amplification of tide at the Bransfield and Gerlache Straits, northwestern Antarctic Peninsula

The propagation and amplification of the tide at the Gerlache and Bransfield Straits, northwestern side of the Antarctic Peninsula, was studied by analysis of thirteen series of direct sea level measurements. Harmonic analysis was performed to obtain the amplitudes and phases of the M_2, S_2, O_1 and K_1 tidal constituents. Based on the computed harmonic constants, cotidal and corange charts of these main constituents were prepared. The M_2 cotidal lines are parallel to the coast and show predominantly southeastward propagation, except at the western side of the Trinity Peninsula, where the M_2 wave pivots to enter the Bransfield Strait from the Weddell Sea and turns southwestward. M_2 amplitudes present a southwestward decrease. S_2 cotidal lines are normal to the Antarctic Peninsula coast and show southwestward propagation. S_2 corange lines increase eastward from the Gerlache Strait to the Antarctic Strait. O_1 and K_1 cotidal lines are also normal to the Antarctic Peninsula coast. Diurnal amplitudes are alike in the study area except at the northwestern side of the Antarctic Strait where they present a maximum gradient. Amplitudes of the main tidal constituents are higher in the northwestern Weddell Sea than at the northwestern side of the peninsula. This fact explains the maximum tidal amplitudes observed at the Antarctic Strait in comparison to the Bransfield Strait

One-dimensional tidal model of the Ría San Julián, Argentina

Se implementó un modelo numérico unidimensional para sistemas de canales interconectados con el fin de simular la hidrodinámica de la marea de la ría San Julián, Argentina. En posiciones prefijadas dentro del sistema se pronosticaron la altura de la superficie libre y los caudales, utilizando un método implícito en diferencias finitas. Los resultados de la simulación numérica se compararon con mediciones de campo, y se obtuvo una correlación satisfactoria entre marea y corrientes predichas y observadas.A one-dimensional numerical model for a system of interconnected channels was implemented to simulate the tidal hydraulics of the Ría San Julián, Argentina. Free surface displacement and discharge were computed from predetermined locations throughout the system using an implicit, finite-difference technique. The results of the numerical simulation were compared with field measurements, and a satisfactory correlation was obtained between observed and predicted tides and currents.Este documento es bilingüe: español-inglésFacultad de Ciencias Naturales y Muse

Estudio de la marea en el borde de la barrera Larsen, Mar de Weddell noroccidental

El objetivo de este trabajo es el estudio de la marea en el borde de la barrera Larsen (latitud: 64° 54' 14" S, longitud: 60° 02' 36" W) en el mar de Weddell noroccidental, Antártida. Los niveles del mar se registraron con un sensor de presión y mediante nivelación geométrica (mira y nivel). El coeficiente de determinación de los niveles del mar obtenidos con ambas técnicas es de 0.96. Se presentan las constantes armónicas de las componentes de marea más energéticas. Se realiza un análisis comparativo entre las constantes calculadas y las que surgen de modelos mareológicos globales y se discute la propagación de la marea en el mar de Weddell noroccidental. Se tipificó el régimen de marea cuantitativamente mediante el coeficiente de Courtier resultando un régimen mixto preponderantemente semidiurno. Los niveles del mar registrados en esta zona de la Antártida son inéditos debido a que el sitio de mediciones fue inaccesible durante muchos años.The objective of this paper is the study of the tide at the Larsen iceshelf boundary (latitude: 64° 54' 14" S, longitude: 60° 02' 36" W), Northwestern Weddell Sea, Antarctica. Sea levels were recorded using pressure sensor and geometric leveling (sight and level). The determination coefficient from sea level gathered with both methods is 0.96. Harmonic constants of the most energetic tidal constituents are presented. A comparative analysis between calculated harmonic constants and those obtained from tidal global models is made and tidal propagation in the Northwestern Weddell Sea is discussed. Tidal regimen is quantified by means of the Courtier coefficient and a preponderantly semidiurnal mixed tide is obtained. Sea levels gathered in this zone of the Antarctica are completely new because the place where the measurements were made was inaccessible for a large period of years.Asociación Argentina de Geofísicos y Geodesta

Non-oncological neuroradiological manifestations in nf1 and their clinical implications

Neurofibromatosis type 1 (NF1), the most frequent phakomatosis and one of the most common inherited tumor predisposition syndromes, is characterized by several manifestations that pervasively involve central and peripheral nervous system structures. The disorder is due to mutations in the NF1 gene, which encodes for the ubiquitous tumor suppressor protein neurofibromin; neurofibromin is highly expressed in neural crest derived tissues, where it plays a crucial role in regulating cell proliferation, differentiation, and structural organization. This review article aims to provide an overview on NF1 non-neoplastic manifestations of neuroradiological interest, involving both the central nervous system and spine. We also briefly review the most recent MRI functional findings in NF1

Identification of a Novel Gene Signature of ES Cells Self-Renewal Fluctuation through System-Wide Analysis

Embryonic Stem cells (ESCs) can be differentiated into ectoderm, endoderm, and mesoderm derivatives, producing the majority of cell types. In regular culture conditions, ESCs' self-renewal is maintained through molecules that inhibit spontaneous differentiation enabling long-term cellular expansion. This undifferentiating condition is characterized by multiple metastable states that fluctuate between self-renewal and differentiation balance. Here, we aim to characterize the high-pluripotent ESC metastate marked by the expression of Zscan4 through a supervised machine learning framework based on an ensemble of support vector machine (SVM) classifiers. Our study revealed a leukaemia inhibitor factor (Lif) dependent not-canonical pluripotency signature (AF067063, BC061212, Dub1, Eif1a, Gm12794, Gm13871, Gm4340, Gm4850, Tcstv1/3, and Zfp352), that specifically marks Zscan4 ESCs' fluctuation. This novel ESC metastate is enhanced by high-pluripotency culture conditions obtained through Extracellular signal Regulated-Kinase (ERK) and Glycogen synthase kinase-3 (Gsk-3) signaling inhibition (2i). Significantly, we reported that the conditional ablation of the novel ESC metastate marked by the expression of Gm12794 is required for ESCs self-renewal maintenance. In conclusion, we extend the comprehension of ESCs biology through the identification of a novel molecular signature associated to pluripotency programming

Intrinsic Abnormalities of Cystic Fibrosis Airway Connective Tissue Revealed by an In Vitro 3D Stromal Model

Cystic fibrosis is characterized by lung dysfunction involving mucus hypersecretion, bacterial infections, and inflammatory response. Inflammation triggers pro-fibrotic signals that compromise lung structure and function. At present, several in vitro cystic fibrosis models have been developed to study epithelial dysfunction but none of these focuses on stromal alterations. Here we show a new cystic fibrosis 3D stromal lung model made up of primary fibroblasts embedded in their own extracellular matrix and investigate its morphological and transcriptomic features. Cystic fibrosis fibroblasts showed a high proliferation rate and produced an abundant and chaotic matrix with increased protein content and elastic modulus. More interesting, they had enhanced pro-fibrotic markers and genes involved in epithelial function and inflammatory response. In conclusion, our study reveals that cystic fibrosis fibroblasts maintain in vitro an activated pro-fibrotic state. This abnormality may play in vivo a role in the modulation of epithelial and inflammatory cell behavior and lung remodeling. We argue that the proposed bioengineered model may provide new insights on epithelial/stromal/inflammatory cells crosstalk in cystic fibrosis, paving the way for novel therapeutic strategies

Can pontine trigeminal T2-hyperintensity suggest herpetic etiology of trigeminal neuralgia?

Background: Trigeminal neuralgia (TN) is usually classified into two different categories: idiopathic and secondary. We have investigated the frequency of brainstem pontine lesions in patients with idiopathic TN without multiple sclerosis (MS) or stroke, and their association with herpes zoster (HZ) infection. Methods: Brain magnetic resonance imaging (MRI) studies of 28 patients with TN were retrospectively reviewed. Results: We found seven patients with clinical suspicion of HZ infection and pontine T2 hyperintense lesions, associated with nerve atrophy in one case. Fifteen patients had a neurovascular conflict (NVC) without brainstem involvement, two of them associated with trigeminal atrophy, while four patients had only volumetric reduction of the nerve. In all patients MRI findings were ipsilateral to the side of TN. Conclusions: Pontine T2 hyperintensities could be considered as a MRI sign of TN in patients without NVCs. This "trigeminal pontine sign" (TPS) is frequently found in association with herpetic infections