221 research outputs found
Advanced GN&C Technologies for TAEM: Flight Test Results of the Italian Unmanned Space Vehicle
This paper describes the guidance, navigation and control challenges posed by the Unmanned Space Vehicles Program. Within the framework of this program the Italian Aerospace Research Center has conceived several advanced GN&C technologies useful in the Terminal Area Energy Management phase of a re-entry flight pattern. These technologies were flight tested during the first two dropped transonic flight tests (DTFT1 and DTFT2) of the program. More specifically, this paper will present the design of the adaptive guidance algorithms developed to accomplish the mission objectives of the DTFT2 flight test. Flight results will be shown in order to state the performance of the guidance strategy putting in evidence, where possible, its most promising aspects for future TAEM applications
Interpreting the Media Logic behind Editorial Decisions
This article enters into debates about media logic in political coverage by way of a case study of the 2015 U.K. General Election. We quantitatively and qualitatively examine two dominant themes of coverage—news about campaign rallies and horse-race reporting—as both are widely seen in political communication scholarship as symptomatic of a media logic. We draw on a content analysis of BBC, ITV, Sky News, Channel 4, and Channel 5 U.K. national television newscasts and semi-structured interviews with their heads of news and/or senior editors to help interpret how far a media logic was the editorial driving force behind coverage. At face value, our content analysis appears to support the media logic thesis, with all broadcasters—in particular commercial television newscasts—covering more process than policy issues. But our case study questions the antecedents of media logic and shines a light on a political logic that may have remained in the dark in large-scale content analysis studies. In following a political logic, we argue that this promoted the horse-race narrative, and naturalized the parties’ highly stage-managed rallies and walkabout
Stoics against stoics in Cudworth's "A Treatise of Freewill"
In his 'A Treatise of Freewill', Ralph Cudworth argues against Stoic determinism by drawing on what he takes to be other concepts found in Stoicism, notably the claim that some things are ‘up to us’ and that these things are the product of our choice. These concepts are central to the late Stoic Epictetus and it appears at first glance as if Cudworth is opposing late Stoic voluntarism against early Stoic determinism. This paper argues that in fact, despite his claim to be drawing on Stoic doctrine, Cudworth uses these terms with a meaning first articulated only later, by the Peripatetic commentator Alexander of Aphrodisias
Energy transfer from the freshwater to the wastewater network using a PAT-equipped turbopump
A new strategy to increase the energy efficiency in a water network exists using turbo pumps, which are systems consisting of a pump and a turbine directly coupled on a same shaft. In a turbo pump, the pump is fed by a turbine that exploits a surplus head in a freshwater network in order to produce energy for one system (wastewater) and reduce the excess pressure in another (drinking water). A pump as turbine (PAT) may be preferred over a classic turbine here due to its lower cost. The result of such a coupling is a PAT-pump turbocharger (P&P). In this research, the theoretical performance of a P&P plant is employed using data from a real water distribution network to exploit the excess pressure of a freshwater stream and to feed a pump conveying wastewater toward a treatment plant. Therefore, the P&P plant is a mixed PAT-pump turbocharger, operating with both fresh and wastewater. A new method to perform a preliminary geometric selection of the machines constituting the P&P plant has been developed. Furthermore, the plant operation has been described by means of a new mathematical model under different boundary conditions. Moreover, the economic viability of the plant has been assessed by comparison with a conventional wastewater pumping system working in ON/OFF mode. Therefore, the net present value (NPV) of the investment has been evaluated in both situations for different time periods. According to the economical comparison, the PAT-pump turbocharger represents the most economically advantageous configuration, at least until the useful life of the plant. Such convenience amounts to 175% up to a time period equal to 20 years
Acondicionamiento digital de señales biológicas de origen cardíaco
En los últimos 30 años, el análisis y acondicionamiento de señales representadas en forma digital ha tenido un notable crecimiento. Gracias a los continuos avances en las tecnologías de integración de circuitos electrónicos y sistemas de procesamientos, se puede decir que estas técnicas están reemplazando en forma paulatina a los métodos y circuitos analógicos. En el presente trabajo se describen aplicaciones dela Transformada Waveletpara el filtrado de señales digitales correspondientes a registros electrocardiográficos.
PTEN deficiency and mutant p53 confer glucose-addiction to thyroid cancer cells: impact of glucose depletion on cell proliferation, cell survival, autophagy and cell migration.
Proliferating cancer cells oxidize glucose through the glycolytic pathway. Since this metabolism is less profitable in terms of ATP production, cancer cells consume large quantity of glucose, and those that experience insufficient blood supply become glucose-addicted. We have analyzed the response to glucose depletion in WRO and FTC133 follicular thyroid cancer cells, which differ in the expression of two key regulators of the glucose metabolism. WRO cells, which express wild type p53 and PTEN, showed a higher rate of cell proliferation and were much less sensitive to glucose-depletion than FTC133 cells, which are PTEN null and express mutant p53. Glucose depletion slowed-down the autophagy flux in FTC133 cells, not in WRO cells. In a wound-healing assay, WRO cells were shown to migrate faster than FTC133 cells. Glucose depletion slowed down the cell migration rate, and these effects were more evident in FTC133 cells. Genetic silencing of either wild-type PTEN or p53 in WRO cells resulted in increased uptake of glucose, whereas the ectopic expression of PTEN in FTC133 cells resulted in diminished glucose uptake. In conclusion, compared to WRO, FTC133 cells were higher glucose up-taker and consumer. These data do not support the general contention that cancer cells lacking PTEN or expressing the mutant p53R273H are more aggressive and prone to better face glucose depletion. We propose that concurrent PTEN deficiency and mutant p53 leads to a glucose-addiction state that renders the cancer cell more sensitive to glucose restriction. The present observation substantiates the view that glucose-restriction may be an adjuvant strategy to combat these tumours
New Challenges towards Smart Systems’ Efficiency by Digital Twin in Water Distribution Networks
Nowadays, in the management of water distribution networks (WDNs), particular attention is paid to digital transition and the improvement of the energy efficiency of these systems. New technologies have been developed in the recent years and their implementation can be crucial to achieve a sustainable level of water networks, namely, in water and energy losses. In particular, Digital Twins (DT) represents a very innovative technology, which relies on the integration of virtual network models, optimization algorithms, real time data collection, and smart actuators information with Geographic Information System (GIS) data. This research defines a new methodology for an efficient application of DT expertise within water distribution networks. Assuming a DMA of a real water distribution network as a case study, it was demonstrated that a fast detection of leakage along with an optimal setting of pressure control valves by means of DT together with an optimization procedure can ensure up to 28% of water savings, contributing to significantly increase the efficiency of the whole system
Non-local parabolic and hyperbolic models for cell polarisation in heterogeneous cancer cell populations
Tumours consist of heterogeneous populations of cells. The subpopulations can have different features, including cell motility, proliferation and metastatic potential. The interactions between clonal sub-populations are complex, from stable coexistence to dominant behaviours. The cell-cell interactions, i.e., attraction, repulsion and alignment, processes critical in cancer invasion and metastasis, can be influenced by the mutation of cancer cells. In this study, we develop a mathematical model describing cancer cell invasion and movement for two polarised cancer cell populations with different levels of mutation. We consider a system of non-local hyperbolic equations that incorporate cell-cell interactions in the speed and the turning behaviour of cancer cells, and take a formal parabolic limit to transform this model into a non-local parabolic model. We then investigate the possibility of aggregations to form, and perform numerical simulations for both hyperbolic and parabolic models, comparing the patterns obtained for these models
Aggregation and travelling wave dynamics in a two-population model of cancer cell growth and invasion
Funding: Engineering and Physical Sciences Research Council (UK) grant numbers EP/L504932/1 (VB), EP/K033689/1 (RE).Cells adhere to each other and to the extracellular matrix (ECM) through protein molecules on the surface of the cells. The breaking and forming of adhesive bonds, a process critical in cancer invasion and metas- tasis, can be influenced by the mutation of cancer cells. In this paper, we develop a nonlocal mathematical model describing cancer cell invasion and movement as a result of integrin-controlled cell-cell adhesion and cell-matrix adhesion, for two cancer cell populations with different levels of mutation. The partial differential equations for cell dynamics are coupled with ordinary differential equations describing the extracellular matrix (ECM) degradation and the production and decay of integrins. We use this model to investigate the role of cancer mutation on the possibility of cancer clonal competition with alternating dominance, or even competitive exclusion (phenomena observed experimentally). We discuss different possible cell aggregation patterns, as well as travelling wave patterns. In regard to the travelling waves, we investigate the effect of cancer mutation rate on the speed of cancer invasion.Publisher PDFPeer reviewe
Procesamiento matemático de señales de origen cardíaco
El presente proyecto pretende verificar la pertinencia de las herramientas matemáticas asociadas al Análisis de Señales, en especial los métodos tiempo-frecuencia, en el análisis y sistematización de señales biológicas, en particular las de origen cardíaco.
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