Reproductive biology of lesser spotted dogfish Scyliorhinus canicula (L., 1758) in the Cantabrian Sea

This paper examines sexual maturity of the female lesser spotted dogfish Scyliorhinus canicula (L., 1758) in the Cantabrian Sea (north of Spain). Analyses made using data collected from commercial trawlers during 1994 and 1995 showed that females reach sexual maturity at a length of 54.2 cm, and the mean egg-laying size is 56.4 ± 0.94 cm. At least one in six adult female dogfish carried egg-capsules during the study period. Sex-ratio by depth strata indicates a larger proportion of females in deeper waters. Mature and spawning females were found at depths ranging from 100 m to more than 400 m, with their proportion being larger in the deeper strata.No disponibl

Upward Point-Set Embeddability

We study the problem of Upward Point-Set Embeddability, that is the problem of deciding whether a given upward planar digraph $D$ has an upward planar embedding into a point set $S$. We show that any switch tree admits an upward planar straight-line embedding into any convex point set. For the class of $k$-switch trees, that is a generalization of switch trees (according to this definition a switch tree is a $1$-switch tree), we show that not every $k$-switch tree admits an upward planar straight-line embedding into any convex point set, for any $k \geq 2$. Finally we show that the problem of Upward Point-Set Embeddability is NP-complete

ERTS: A multispectral image analysis contribution for the geomorphological evaluation of southern Maracaibo Lake Basin

Multispectral analysis of ERTS-A images at scales of 1:1,000,000 and 1:500,000 has been conducted with conventional photointerpretation methods. Specific methods have been developed for the geomorphological analysis of southern Maracaibo Lake Basin which comprises part of the Venezuelan Andean Range, Perija Range, the Tachira gap and the Southern part of the Maracaibo Lake depression. A steplike analysis was conducted to separate macroforms, landscapes and relief units as well as drainage patterns and tectonic features, which permitted the delineation of tectonic provinces, stratigraphic units, geomorphologic units and geomorphologic positions. The geomorphologic synthesis obtained compares favorably with conventional analysis made on this area for accuracy of 1:100,000 scale, and in some features with details obtained through conventional analysis for accuracy of 1:15,000 and field work. Geomorphological units in the mountains were identified according to changes in tone, texture, forms orientation of interfluves and tectonic characteristics which control interfluvial disimetrics

State-independent quantum violation of noncontextuality in four dimensional space using five observables and two settings

Recently, a striking experimental demonstration [G. Kirchmair \emph{et al.}, Nature, \textbf{460}, 494(2009)] of the state-independent quantum mechanical violation of non-contextual realist models has been reported for any two-qubit state using suitable choices of \emph{nine} product observables and \emph{six} different measurement setups. In this report, a considerable simplification of such a demonstration is achieved by formulating a scheme that requires only \emph{five} product observables and \emph{two} different measurement setups. It is also pointed out that the relevant empirical data already available in the experiment by Kirchmair \emph{et al.} corroborate the violation of the NCR models in accordance with our proof

Comparison of predator-parasitoid-prey interaction models for different host plant qualities

Population dynamics models suggest that the over-all level of resource productivity plays an important role in community dynamics. One such factor of resource productivity is the quality of the host plant, which can determine the effectiveness of entomophagous (predatory and parasitoid) species by altering the growth rate of the phytophagous population via effects on fecundity, survival, and rate of development. These effects have been studied in relation to the distribution of host plants and their physiological state. However, few studies have considered the differences among plant cultivars. The objective of this study was to identify a continuous-time dynamic model, to describe the effects of different tomato cultivars on a one predatortwo prey model. The experiment was carried out under greenhouse conditions using ten tomato cultivars, with the predatory species Nesidiocoris tenuis (Reuter) (Insecta, Hemiptera, Miridae) and two prey species: the phytophagous species Bemisia tabaci (Gennadius) (Insecta, Hemiptera, Aleyrodidae) and the parasitoid species Trichogramma achaeae (Nagaraja & Nagarkatti) (Insecta, Hymenoptera, Trichogrammatidae); the latter was used as the intraguild-prey. Using the software SIMFIT, we found that a three-dimensional Lotka-Volterra type system could be well fitted to the data, estimating the phytophagous species´ growth rate, the parasitoid and predator mortality rates, the predation and parasitism rates, and the parasitoid emergence rate according to the cultivar type. The results showed an important effect of the host plant quality, by cultivar, on intraguild predation, resulting in important changes in the dynamics of phytophagous populations. These results are also discussed in relation to their importance in the biological control of pest species in greenhouse crops

Bell's theorem with and without inequalities for the three-qubit Greenberger-Horne-Zeilinger and W states

A proof of Bell's theorem without inequalities valid for both inequivalent classes of three-qubit entangled states under local operations assisted by classical communication, namely Greenberger-Horne-Zeilinger (GHZ) and W, is described. This proof leads to a Bell inequality that allows more conclusive tests of Bell's theorem for three-qubit systems. Another Bell inequality involving both tri- and bipartite correlations is introduced which illustrates the different violations of local realism exhibited by the GHZ and W states.Comment: REVTeX4, 5 pages, 3 figure

Quantum mechanical effect of path-polarization contextuality for a single photon

Using measurements pertaining to a suitable Mach-Zehnder(MZ) type setup, a curious quantum mechanical effect of contextuality between the path and the polarization degrees of freedom of a polarized photon is demonstrated, without using any notion of realism or hidden variables - an effect that holds good for the product as well as the entangled states. This form of experimental context-dependence is manifested in a way such that at \emph{either} of the two exit channels of the MZ setup used, the empirically verifiable \emph{subensemble} statistical properties obtained by an arbitrary polarization measurement depend upon the choice of a commuting(comeasurable) path observable, while this effect disappears for the \emph{whole ensemble} of photons emerging from the two exit channels of the MZ setup.Comment: To be published in IJT

On a Tree and a Path with no Geometric Simultaneous Embedding

Two graphs $G_1=(V,E_1)$ and $G_2=(V,E_2)$ admit a geometric simultaneous embedding if there exists a set of points P and a bijection M: P -> V that induce planar straight-line embeddings both for $G_1$ and for $G_2$. While it is known that two caterpillars always admit a geometric simultaneous embedding and that two trees not always admit one, the question about a tree and a path is still open and is often regarded as the most prominent open problem in this area. We answer this question in the negative by providing a counterexample. Additionally, since the counterexample uses disjoint edge sets for the two graphs, we also negatively answer another open question, that is, whether it is possible to simultaneously embed two edge-disjoint trees. As a final result, we study the same problem when some constraints on the tree are imposed. Namely, we show that a tree of depth 2 and a path always admit a geometric simultaneous embedding. In fact, such a strong constraint is not so far from closing the gap with the instances not admitting any solution, as the tree used in our counterexample has depth 4.Comment: 42 pages, 33 figure

On the Mechanism of Magnesium Storage in Microand Nano-Particulate Tin Battery Electrodes

This study reports on the electrochemical alloying-dealloying properties of Mg2Sn intermetallic compounds. 119Sn Mössbauer spectra of -Sn powder, thermally alloyed cubic-Mg2Sn, and an intermediate MgSn nominal composition are used as references. The discharge of a Mg/micro-Sn half-cell led to significant changes in the spectra line shape, which is explained by a multiphase mechanism involving the coexistence of c-Mg2Sn, distorted Mg2����� Sn, and Mg-doped -Sn. Capacities and capacity retention were improved by using nanoparticulate tin electrodes. This material reduces significantly the diffusion lengths for magnesium and contains surface SnO and SnO2, which are partially electroactive. The half-cell potentials were suitable to be combined versus the MgMn2O4 cathodes. Energy density and cycling properties of the resulting full Mg-ion cells are also scrutinize