Measurement errors with low-cost citizen science radiometers

The KdUINO is a Do-It-Yourself buoy with low-cost radiometers that measure a parameter related to water transparency, the diffuse attenuation coefficient integrated into all the photosynthetically active radiation. In this contribution, we analyze the measurement errors of a novel low-cost multispectral radiometer that is used with the KdUINO.Peer Reviewe

Strong Secrecy on a Class of Degraded Broadcast Channels Using Polar Codes

Different polar coding schemes are proposed for the memoryless degraded broadcast channel under different reliability and secrecy requirements: layered decoding and/or layered secrecy. In this setting, the transmitter wishes to send multiple messages to a set of legitimate receivers keeping them masked from a set of eavesdroppers. The layered decoding structure requires receivers with better channel quality to reliably decode more messages, while the layered secrecy structure requires eavesdroppers with worse channel quality to be kept ignorant of more messages. The implementation of the proposed polar coding schemes is discussed and their performance is evaluated by simulations for the symmetric degraded broadcast channel.Comment: 35 pages. Published in "MDPI Entropy". A short version of this paper had been accepted to the 3rd Workshop on Physical-Layer Methods for Wireless Security, IEEE CNS 201

Persistence of periodic solutions for higher order perturbed differential systems via Lyapunov-Schmidt reduction

In this work we first provide sufficient conditions to assure the persistence of some zeros of functions having the form $$g(z,\varepsilon)=g_0(z)+\sum_{i=1}^k \varepsilon^i g_i(z)+\mathcal{O}(\varepsilon^{k+1}),$$ for $|\varepsilon|\neq0$ sufficiently small. Here $g_i:\mathcal{D}\rightarrow\mathbb{R}^n$, for $i=0,1,\ldots,k$, are smooth functions being $\mathcal{D}\subset \mathbb{R}^n$ an open bounded set. Then we use this result to compute the bifurcation functions which controls the periodic solutions of the following $T$-periodic smooth differential system $$x'=F_0(t,x)+\sum_{i=1}^k \varepsilon^i F_i(t,x)+\mathcal{O}(\varepsilon^{k+1}), \quad (t,z)\in\mathbb{S}^1\times\mathcal{D}.$$ It is assumed that the unperturbed differential system has a sub-manifold of periodic solutions $\mathcal{Z}$, $\textrm{dim}(\mathcal{Z})\leq n$. We also study the case when the bifurcation functions have a continuum of zeros. Finally we provide the explicit expressions of the bifurcation functions up to order 5

"Proctoeces maculatus" "(Trematoda: Digenea)", paràsit del musclo "Mytilus edulis": Estructura, desenvolupament i ultrastructura de la cercària

About 1 % of the mussel beds of the Galician coast are affected by the so called «orange sickness», a disease detected for the first time by COLE (1935) and caused by Proctoeces maculatus (Trematoda: Digenea), whose sporocysts, approximately one thousand in number, infect different organs of the host, amongst the most important of which are the pallium and the gonads. The sporocist has the shape of an oval bag in which sporocysts in formation as well as cercariae in different developping phases dwell; some morphological differences between the latter and the former appear already during the early phases. The acetabulum of the cercaria differenciates itself as a spherical cavity whose wall presents muscular fibres in radial and circular directions. At the same time, the cercaria's own teguments are being developped and the tegumentary cover that surrounds it degenerates during development, which originated in the sporocyst's wall. Cells of a connective tissue nature form the parenchyma of the cercaria, which present very well defined boundaries and scarcity of intercellular matter

Utilización de imágenes para introducir conceptos en las clases de ciencias : el caso de la conservación de la energía

La enseñanza de las ciencias, al igual que la propia ciencia, hace uso de diferentes lenguajes: lenguaje verbal, matemático, visual. La creación de significado científico se hace mediante la integración de varios de estos lenguajes. Este tipo de relación entre ellos se suele denominar multimodalidad

Melnikov analysis in nonsmooth differential systems with nonlinear switching manifold

We study the family of piecewise linear differential systems in the plane with two pieces separated by a cubic curve. Our main result is that 7 is a lower bound for the Hilbert number of this family. In order to get our main result, we develop the Melnikov functions for a class of nonsmooth differential systems, which generalizes, up to order 2, some previous results in the literature. Whereas the first order Melnikov function for the nonsmooth case remains the same as for the smooth one (i.e. the first order averaged function) the second order Melnikov function for the nonsmooth case is different from the smooth one (i.e. the second order averaged function). We show that, in this case, a new term depending on the jump of discontinuity and on the geometry of the switching manifold is added to the second order averaged function

New results on averaging theory and applications

Agraïments: The first author is supported by CNPq 248501/2013-5. CAPES grant 88881.030454 /2013-01 from the Program CSF-PVEThe usual averaging theory reduces the computation of some periodic solutions of a system of ordinary differential equations, to find the simple zeros of an associated averaged function. When one of these zeros is not simple, i.e. the Jacobian of the averaged function in it is zero, the classical averaging theory does not provide information about the periodic solution associated to a non simple zero. Here we provide sufficient conditions in order that the averaging theory can be applied also to non simple zeros for studying their associated periodic solutions. Additionally we do two applications of this new result for studying the zero--Hopf bifurcation in the Lorenz system and in the Fitzhugh--Nagumo system