54 research outputs found
Calculations for Extended Thermodynamics of dense gases up to whatever order and with all the symmetries
The 14 moments model for dense gases, introduced in the last years by Arima,
Taniguchi Ruggeri, Sugiyama, is here considered. They have found the closure of
the balance equations up to second order with respect to equilibrium; here the
closure is found up to whatever order with respect to equilibrium, but for a
more constrained system where more symmetry conditions are imposed and this in
agreement with the suggestion of the kinetic theory. The results, when
restricted at second order with respect to equilibrium, are the same of the
previously cited model but under the further restriction of full symmetries.Comment: arXiv admin note: substantial text overlap with arXiv:1410.405
Snyder-de Sitter model from two-time physics
We show that the symplectic structure of the Snyder model on a de Sitter
background can be derived from two-time physics in seven dimensions and propose
a Hamiltonian for a free particle consistent with the symmetries of the model.Comment: 9 page
Big Ideas of Cryptography in Primary School
We present a learning path on cryptography for primary school students (Grade 5), which we designed and tested. The project aims to raise initial awareness of the core ideas of modern cryptography, which are fundamental concepts for becoming informed and active citizens in modern digital society. For this reason, we designed a progression of unplugged activities (sometimes integrated with task-specific, block-based programming environments) to expose students to different cryptographic techniques, where each new activity is motivated by an analysis of the criticalities encountered previously. We used unplugged activities to show that Computer Science (CS) does not necessarily imply the use of digital devices and to allow students to focus on its general scientific principles. We describe the designed learning module, discuss the main hinges in the experiment, and reflect on the lessons learned. The final evaluation showed excellent learning outcomes and high satisfaction with the activities. As cryptography uses mathematical tools (e.g., modular arithmetic, statistics), some parts of which are within reach of primary school children but rarely taught to them, it was possible to dwell on these aspects, making them experience mathematical objects in a non-standard context, and also stimulating a greater awareness of the impact of mathematics and CS in everyday life
An exact fluid model for relativistic electron beams: The many moments case
An interesting and satisfactory fluid model has been proposed in literature
for the the description of relativistic electron beams. It was obtained with 14
independent variables by imposing the entropy principle and the relativity
principle. Here the case is considered with an arbitrary number of independent
variables, still satisfying the above mentioned two principles; these lead to
conditions whose general solution is here found. We think that the results
satisfy also a certain ordering with respect to a smallness parameter
measuring the dispersion of the velocity about the mean; this
ordering generalizes that appearing in literature for the 14 moments case
Extended Thermodynamics for Dense Gases up to Whatever Order and with Only Some Symmetries
Extended Thermodynamics of dense gases is characterized by two hierarchies of field
equations, which allow one to overcome some restrictions on the generality of the previous
models. This idea has been introduced by Arima, Taniguchi, Ruggeri and Sugiyama. In~the
case of a 14-moment model, they have found the closure of the balance equations up to
second order with respect to equilibrium. Here, the closure is obtained up to whatever
order and imposing only the necessary symmetry conditions. It comes out that the first
non-symmetric parts of the higher order fluxes appear only at third order with respect to
equilibrium, even if Arima, Taniguchi, Ruggeri and Sugiyama found a non-symmetric part
proportional to an arbitrary constant also at first order with respect to equilibrium.
Consequently, this constant must be zero, as Arima, Taniguchi, Ruggeri and Sugiyama assumed
in the applications and on an intuitive ground
The general exact solution for the many moments macroscopic approach to extended thermodynamics of polyatomic gases
A new model for Polyatomic and for Dense Gases has been proposed in literature in the last five years in
the framework of Extended Thermodynamics. The case with an arbitrary but fixed number of moments has been
recently studied, both with the kinetic approach than with the macroscopic approach; this last one is
more general and includes the results of the kinetic approach only as a particular case. \\
Scope of the "closure problem" is to find the expression of some arbitrary functions which appear in the
balance equations. Up to now only a recurrence procedure has been published which outlines how to find
the solution of this problem with the macroscopic approach; by using this procedure, a numberable set
of solutions has been found and written explicitly, while we find here the most general exact
solution. It is determined except for some arbirary terms and it is interesting that these terms appear
also in the 24 moments model; so we find here that they are transmitted from the model with 24 moments
to those with an arbitrary number of moments, without any further arbitrary term
Platinated Nucleotides are Substrates for the Human Mitochondrial Deoxynucleotide Carrier (DNC) and DNA Polymerase g: Relevance for the Development of New Platinum-Based Drugs.
cis-[PtCl2(NH3)2] (cisplatin) is among the highest effective antitumor drugs used for the chemotherapeutic treatment of a broad range of malignancies. Recently, alongside with the classical direct bond to DNA, an alternative mechanism of action mediated by N7 platinated nucleotides has been suggested for cisplatin. Considering that mitochondria play an important role in cell death activation and in a significant portion of the clinical activity and pharmacological properties associated with cisplatin,
aim of this research was to evaluate the possibility that platinated deoxynucleotides, as the model complex [Pt(dien)(N7-5’-dGTP)] (1), dien=diethylenetriamine, could be transported into mitochondria and then incorporated into mtDNA. The kinetic characterization has revealed that the mitochondrial deoxynucleotide carrier (DNC) transports complex 1 with high affinity. Finally, a highly efficient in organello DNA synthesis system, followed by ICP-AES, has demonstrated that [Pt(dien)(N7-5’-dGTP)] is incorporated in the mitochondrial DNA by DNA polymerase g. These results may have critical implications in the development of new generations of anticancer and/or antiviral nucleotide analogues with more specific cellular targets and fewer side effects
A Minimal Snap Extension to Improve the Treatment of Integer Data: A Constructionist Approach
Block based programming environments are a fundamental resource in introducing students to coding, an activity that has been proven to be useful in the development of competences laying in the field of mathematics. Unfortunately, it has been recently shown that Scratch, the most famous and diffused among those languages, presents an important lack in the treatment of Integer data: it does not provide easy and intuitive instruments to face problems dealing with the division with remainder. This conflicts with Scratch’s aim and could also bring students to create misconceptions about the division operation. For this reason, a minimal Snap extension will be here proposed, which overcomes this problem by creating a block environment more pertinent from a mathematical perspective
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