6,409 research outputs found
Levi umbilical surfaces in complex space
We define a complex connection on a real hypersurface of \C^{n+1} which is
naturally inherited from the ambient space. Using a system of Codazzi-type
equations, we classify connected real hypersurfaces in \C^{n+1}, ,
which are Levi umbilical and have non zero constant Levi curvature. It turns
out that such surfaces are contained either in a sphere or in the boundary of a
complex tube domain with spherical section.Comment: 18 page
Collective dynamics of dense hairy surfaces in turbulent flow
Flexible filamentous beds interacting with a turbulent flow represent a
fundamental setting for many environmental phenomena, e.g., aquatic canopies in
marine current. Exploiting direct numerical simulations at high Reynolds number
where the canopy stems are modelled individually, we provide evidence on the
essential features of the honami/monami collective motion experienced by hairy
surfaces over a range of different flexibilities, i.e., Cauchy number. Our
findings clearly confirm that the collective motion is essentially driven by
fluid flow turbulence, with the canopy having in this respect a fully-passive
behavior. Instead, some features pertaining to the structural response turn out
to manifest in the motion of the individual canopy elements when focusing, in
particular, on the spanwise oscillation and/or on sufficiently small Cauchy
numbers
Dynamic phasors to enable distributed real-time simulation
© 2017 IEEE. Distributed real-time simulation allows the sharing of simulator equipment and components connected in Hardware-In-the-Loop experiments. In this paper, we analyze the challenges of geographically distributed real-time power system simulation and how dynamic phasors could be applied to improve the accuracy of the simulation results for large time steps. The time step is of particular interest since the communication delay between simulators interconnected through wide area network is much larger than the simulation time step typically used in electromagnetic transient real-time simulations. However, commercially available real-time simulators use either the electromagnetic transient or classic complex phasor representation. Results in the dynamic phasor and electromagnetic transient domain are compared to quantify the advantage of dynamic phasor simulations in practice. The test platform for this evaluation is a power system simulator which is currently under development
Evaluation of a Prelicensure Nursing Capstone Preceptorship
https://digitalcommons.psjhealth.org/summit_all/1053/thumbnail.jp
Linalool, a plant-derived monoterpene alcohol, reverses doxorubicin resistance in human breast adenocarcinoma cells
Essential oils from various aromatic plants have been reported to exert chemopreventive and/or antitumor effects. In addition, a number of studies have shown the ability of chemopreventive phytochemicals to increase the sensitivity of cancer cells to conventional anticancer drugs. The success of chemotherapeutic agents is often hindered by the development of drug resistance, with multidrug resistant (MDR) phenotypes reported in a number of tumors, generally involving reduced intracellular drug accumulation due to increased drug efflux by membrane transporters. In the present study, the effects of linalool (LIN), a monoterpene alcohol found in the essential oils from many aromatic plants, on the growth of two human breast adenocarcinoma cell lines, MCF7 WT and multidrug resistant MCF7 AdrR, were investigated, both as a single agent and in combination with doxorubicin (DOX). The results reported here show that LIN only moderately inhibits cell proliferation; interestingly, however, subtoxic concentrations of LIN potentiate DOX-induced cytotoxicity and pro-apoptotic effects in both cell lines. A significant synergism can be observed in MCF7 AdrR cells, which may be due, at least in part, to the ability of LIN to increase DOX accumulation and to induce a decrease in Bcl-xL levels. In summary, the results of the present study suggest that LIN may improve the therapeutic index of anthracyclines in the management of breast cancer, especially in MDR tumors
Ticks in the box: Argas persicus occurrence in nest boxes of secondary cavity-nesting bird species in Italy
Migratory organisms can be vectors of parasitic host organisms that can then be transported along seasonal migratory journeys and spread across continents. Ornithophilic nidicolous ticks (e.g. soft ticks) include species responsible for the transmission of pathogens and bacteria, thus representing a health problem not only for wild species that are directly parasitized, but also for those that share the same environments or reproductive sites with them. In this regard, artificial nests for birds may turn out to be site-sources of parasites. Here, we document the occurrence of different life stages of Argas persicus ticks in nest boxes of wild birds in a natural area (not associated with poultry activities) of central coastal Italy (Maremma Regional Park, Tuscany). Between 2018 and 2022, 168 ticks were collected from nest boxes occupied by different secondary cavity-nesting birds, such as European rollers Coracias garrulus and scops owl Otus scops. Ticks were analysed morphologically, and selected specimens were also identified by mitochondrial ribosomal 16S (16S) subunit gene to ascertain their taxonomic status. All ticks were identified as Argas persicus. This finding not only suggests that this tick species has formed a viable population in this Italian region, but also further confirms the previously doubtful natural origin of the species at country level and sheds new light on its underestimated and little investigated distribution. Possible pathways of introduction and its potential impacts on local avian community are discussed
A transversal educational proposal for prospective primary teachers: The theme of Time
Time is a transversal topic that plays a fundamental role in our every-day experience and represents a natural conceptual bridge between common sense ideas and scientific knowledge. Two classes of Prospective Primary Teachers (PPTs) at the Universities of Udine and Verona were introduced to the theme of Time in a formative intervention organized into a) the discussion of various educational and multidisciplinary approaches aimed to deal with different aspects of Time and b) the exploration/experimentation of various instruments for time measurement. In this work, we study and compare the learning outcomes in terms of planning and implementation of educational projects built by PPTs following two different Rubrics
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