5,571 research outputs found

    Three-dimensional Maxwellian extended Newtonian gravity and flat limit

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    In the present work we find novel Newtonian gravity models in three space-time dimensions. We first present a Maxwellian version of the extended Newtonian gravity, which is obtained as the non-relativistic limit of a particular U(1)-enlargement of an enhanced Maxwell Chern-Simons gravity. We show that the extended Newtonian gravity appears as a particular sub-case. Then, the introduction of a cosmological constant to the Maxwellian extended Newtonian theory is also explored. To this purpose, we consider the non-relativistic limit of an enlarged symmetry. An alternative method to obtain our results is presented by applying the semigroup expansion method to the enhanced Nappi-Witten algebra. The advantages of considering the Lie algebra expansion procedure is also discussed

    Metric-Affine Vector-Tensor correspondence and implications in F(R, T, Q, T, D) gravity

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    We extend the results of antecedent literature on quadratic Metric-Affine Gravity by studying a new quadratic gravity action in vacuum which, besides the usual (non-Riemannian) Einstein-Hilbert contri-bution, involves all the parity even quadratic terms in torsion and non-metricity plus a Lagrangian that is quadratic in the field-strengths of the torsion and non-metricity vector traces. The theory results to be equivalent, on-shell, to a Vector-Tensor theory. We also discuss the sub-cases in which the contribution to the Lagrangian quadratic in the field-strengths of the torsion and non-metricity vectors just exhibits one of the aforementioned quadratic terms. We then report on cosmological aspects of the general quadratic theory in the presence of a perfect cosmological hyperfluid and on implications of our findings in the context of F(R, T, Q, T, D) gravity.(c) 2022 Elsevier B.V. All rights reserved

    The Strange Case: The Unsymmetric Cisplatin-Based Pt(IV) Prodrug [Pt(CH3COO)Cl2(NH3)2(OH)] Exhibits Higher Cytotoxic Activity with respect to Its Symmetric Congeners due to Carrier-Mediated Cellular Uptake

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    The biological behavior of the axially unsymmetric antitumor prodrug (OC-6-44)-acetatodiamminedichloridohydroxidoplatinum(IV), 2, was deeply investigated and compared with that of analogous symmetric Pt(IV) complexes, namely, dihydroxido 1 and diacetato 3, which have a similar structure. The complexes were tested on a panel of human tumor cell lines. Complex 2 showed an anomalous higher cytotoxicity (similar to that of cisplatin) with respect to their analogues 1 and 3. Their reduction potentials, reduction kinetics, lipophilicity, and membrane affinity are compared. Cellular uptake and DNA platination of Pt(IV) complexes were deeply investigated in the sensitive A2780 human ovarian cancer cell line and in the corresponding resistant A2780cisR subline. The unexpected activity of 2 appears to be related to its peculiar cellular accumulation and not to a different rate of reduction or a different efficacy in DNA platination and/or efficiency in apoptosis induction. Although the exact mechanism of cell uptake is not fully deciphered, a series of naive experiments indicates an energy-dependent, carrier-mediated transport: the organic cation transporters (OCTs) are the likely proteins involved

    Studia Lichenologica in Italy. II. New records of Cladonia subgenus Cladina

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    New data relating to populations of Cladonia L. subgenus Cladina are presented for the purposes of updating the distribution of species of community interest

    Formative Assessment and Professional Training: Reflections from a Mathematics course in Bioengineering

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    Bioengineering is currently considered an interdisciplinary professional field which provides solutions to different problems arising in the area of health care. Its strategic importance is widely acknowledged since its developments and proposals could help diminish the level of technological dependence in the sector. The fast pace of innovation in the area of biomedical technology gives rise to permanent reflection on the learning goals and teaching strategies proposed by educators in the different training stages of a bioengineer. In this context, learning assessment appears as a controversial issue which needs to be debated and rethought. This paper describes the reflections of teachers of a Mathematics course within a Bioengineering program around the question, What approach to assessment favors the student's participation, autonomy and training as a future bioengineer? The investigation was carried out in the framework of a Participatory Research Action project and helped us to redesign assessment activities from a different perspective.Fil: Carrere, C.. Universidad Nacional de Entre Ríos. Facultad de Ingeniería; ArgentinaFil: Milesi, S.. Universidad Nacional de Entre Ríos. Facultad de Ingeniería; ArgentinaFil: Lapyckyj, I.. Universidad Nacional de Entre Ríos. Facultad de Ingeniería; ArgentinaFil: Ravera, Emiliano Pablo. Universidad Nacional de Entre Ríos. Facultad de Ingeniería; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Escher, L.. Universidad Nacional de Entre Ríos. Facultad de Ingeniería; ArgentinaFil: Miyara, A.. Universidad Nacional de Rosario; Argentina. Universidad Nacional de Entre Ríos. Facultad de Ingeniería; ArgentinaFil: Pita, G.. Universidad Nacional de Entre Ríos. Facultad de Ingeniería; ArgentinaFil: Añino, M.. Universidad Nacional de Entre Ríos. Facultad de Ingeniería; Argentin

    Microclimatic Alteration after Logging Affects the Growth of the Endangered Lichen Lobaria pulmonaria

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    Microclimatic conditions are important in determining lichen distribution at small scale, and may determine whether the species persist when the surrounding environmental conditions have drastically changed. This is the case with forest management, since a sudden variation of microclimatic conditions (increase of solar radiation, temperature, wind and a reduction of humidity) may occur after logging. In this study, the combined effect of forest logging and microclimatic conditions on the growth probabilities and growth rates of the model species Lobaria pulmonaria was assessed in mixed oak stands. To this purpose, 800 fragments of L. pulmonaria (<1 cm) were transplanted in logged and unlogged stands for two years. Young and adult fragments were positioned on Turkey oak boles according to distance from the ground (100 and 50 cm) and aspect (north and south). The results, evaluated by generalized linear mixed models on a yearly basis, highlighted differences in growth—particularly on isolated trees in the logged stand. South-exposed samples in the logged stand showed a low probability of growth, while samples transplanted north in the unlogged stand showed higher growth probabilities. However, the highest annual growth coefficients corresponded to south-exposed samples 50 cm from the ground in the unlogged stand. In general, higher growth rates were observed in young thallus fragments when compared with adult ones. Beyond confirming the importance of microclimate for lichen ecology, these results could be implemented in conservation actions to preserve L. pulmonaria populations in logged forests

    The tunable resonant IC antenna concept and its design for DTT experiment

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    The intrinsic poor loading of Ion Cyclotron (IC) plasma-facing antennas makes the use of Tuning and Matching Systems (TMSs) a necessity. The antenna plus TMS is a resonant system; in the TMS and access lines high voltages (tens of kV) must be accounted for in the unavoidable unmatched part of the feeding lines. In this work, we propose and test an innovative type of IC launcher; it is based on achieving resonance of the self-standing antenna, i.e. without the TMS. A mechanical full-metal tuning mechanism is described and demonstrated to allow wide-band operation. A systematic analysis of possible antenna topologies has led to identifying a structure that can allow good impedance matching along with compliance with maximum electric field constraints. Most of the design is carried out using a simplified plasma and a commercial analysis tool and then validated with a realistic plasma using TOPICA code
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