Degeneracy between warm and coupled cold dark matter: A clarifying note

Wei et al [PRD 88, 043510 (2013)] have proposed the existence of a cosmological degeneracy between warm dark matter (WDM), modified gravity and coupled cold dark matter (CDM) cosmologies at both the background expansion and the growth of density perturbation levels, i.e., corresponding cosmological data would not be able to differentiate such scenarios. Here, we will focus on the specific indistinguishability between a warm dark matter plus cosmological constant ($\Lambda$) and coupled scalar field-CDM scenarios. Although the statement of Wei et al is true for very specific conditions we present a more complete discussion on this issue and show in more detail that these models are indeed distinguishable. We show that the degeneracy breaks down since coupled models leave a specific signature in the redshift space distortion data which is absent in the uncoupled warm dark matter cosmologies. Furthermore, we complement our claim by providing the reasons which suggest that even at nonlinear level a breaking of such apparent equivalence is also expected.Comment: 6 pages, 1 Figure; revised version, section IV extended and enriched with further discussion, title altered, typos corrected and new references added. Version published in PR

On the colour polymorphism of Philaenus spumarius (L.) (Homoptera, Cercopidae) in Portugal

Copyright © 1997 Museu de Zoologia.On the colour polymorphism of Philaenus spumarius (L) (Homoptera, Cercopidae) in Portugal.- A total of 7,967 specimens (4,354 males and 3,613 females) of the meadow spittlebug Philaenus spumarius (L) collected in three different habitats at Fontanelas (Sintra) were analysed in terms of the colour morph frequencies. Eleven different morphs were encountered: populi (POP), typicus (TYP), trilineatus (TRI), marginellus (MAR). lateralis (LAT). fIavicollis (FLA), gibbus (GIB), ustulatus (UST), quadrimaculatus (QUA), albomaculatus (ALB), and leucophthalmus (LOP). For males and in decreasing order of frequency the following morph groups and morphs proper were found: TYP group (95.38%). TRI group (3.70%), LCE group (0.85%), and LOP group (0.07%); and for females TYP group (88.79%). TRI group (4.01 %). MAR (3.32%). LOP group (1.88%), LCE group (1.74%), and LAT (0.25%). As expected, the TYP group (POP + TYP) was more frequent in males than in females (about 95% VS. 89%, respectively). Moreover, most melanic morphs were exclusively (MAR, LAT, ALB, and LOP) or better represented (FLA and QUA) in females than in males. Results also show that there appear to be differences regarding females among the three habitats studied, in spite of being practically contiguous. The coolest of all three habitats (a Pinus pinaster woodland with a shrub community dominated mostly by U1ex europaea) showed the highest frequencies of the melanic morphs. It is therefore suggested that among other factors, thermal melanism plays an important selective role in the colour polymorphism of the meadow spittlebug at Fontanelas

Pion-Pion Phase-Shifts and the Value of Quark-Antiquark Condensate in the Chiral Limit

We use low energy pion-pion phase-shifts in order to make distinction between the alternatives for the value of the quark-antiquark condensate $B_0$ in the chiral limit. We will consider the amplitude up to and including ${\cal O}(p^4)$ contributions within the Standard and Generalized Chiral Perturbation Theory frameworks. They are unitarized by means of Pad\'e approximants in order to fit experimental phase-shifts in the resonance region. As the best fits correspond to $\alpha = \beta = 1$, we conclude that pion-pion phase-shift analysis favors the standard ChPT scenario, which assumes just one, large leading order parameter $_{_0}$.Comment: 5 pages, 3 figures and 1 tabl

Two Superconducting Phases in CeRh_1-xIr_xIn_5

Pressure studies of CeRh_1-xIr_xIn_5 indicate two superconducting phases as a function of x, one with T_c >= 2 K for x < 0.9 and the other with T_c < 1.2 K for x > 0.9. The higher T_c phase, phase-1, emerges in proximity to an antiferromagnetic quantum-critical point; whereas, Cooper pairing in the lower T_c phase-2 is inferred to arise from fluctuations of a yet to be found magnetic state. The T-x-P phase diagram of CeRh_1-xIr_xIn_5, though qualitatively similar, is distinctly different from that of CeCu_2(Si_1-xGe_x)_2.Comment: 5 pages, 3 figure

Banana: instruções práticas de cultivo.

Importância; Escolha e preparo do terreno; Adubação; Variedades e seleção do material; Espaçamento; Plantio; Tratos; Culturais; Pragas; Broca do rizoma; Tripes; Broca-rajada; Lagartas desfolhadoras; Ácaros de teia; Abelha arapuá; Doenças; Mal-do-Panamá; Sigatoka-amarela; Sigatoka-negra; Colheita.bitstream/CNPMF/23308/1/documento_161.pd

Canopy habitat area effect on the arthropod species densities in the Azores: pondering the contribution of tourist species and other life histories

"[…]. We performed a PIAR examining how plant cover area and plant crown structure influence the densities of arthropods in the canopies of one specific island, comparing various distinct natural reserves. Species densities were measured for two functional insect herbivore guilds (sap-sucking and leaf-chewing insects) and the most common predatory assembly in this system (spiders) in three different ways: i) the average number of specimens per plant; ii) the average number of specimens per transect, providing both fine and broad scales of species abundance (see Methods); iii) absolute numbers per reserve. Moreover, we investigated common versus scarce arthropod species distributions between various plant species. […]" (da Introdução)Fundação para a Ciência e a Tecnologia, Portugal

Experimental Observation of Quantum Correlations in Modular Variables

We experimentally detect entanglement in modular position and momentum variables of photon pairs which have passed through $D$-slit apertures. We first employ an entanglement criteria recently proposed in [Phys. Rev. Lett. {\bf 106}, 210501 (2011)], using variances of the modular variables. We then propose an entanglement witness for modular variables based on the Shannon entropy, and test it experimentally. Finally, we derive criteria for Einstein-Podolsky-Rosen-Steering correlations using variances and entropy functions. In both cases, the entropic criteria are more successful at identifying quantum correlations in our data.Comment: 7 pages, 4 figures, comments welcom

Alterations in brain connectivity due to plasticity and synaptic delay

Brain plasticity refers to brain's ability to change neuronal connections, as a result of environmental stimuli, new experiences, or damage. In this work, we study the effects of the synaptic delay on both the coupling strengths and synchronisation in a neuronal network with synaptic plasticity. We build a network of Hodgkin-Huxley neurons, where the plasticity is given by the Hebbian rules. We verify that without time delay the excitatory synapses became stronger from the high frequency to low frequency neurons and the inhibitory synapses increases in the opposite way, when the delay is increased the network presents a non-trivial topology. Regarding the synchronisation, only for small values of the synaptic delay this phenomenon is observed

Estimando la riqueza de especies de artrópodos en los pastizales de las Azores: eficacia de los métodos de succión y las trampas de caída

Se han investigado las ventajas del uso combinado de técnicas de succión (Vortis) y trampas de caída, a la hora de estimar la riqueza de especies de artrópodos en pastizales antrópicos y seminaturales de tres islas oceánicas de las Azores de origen geológico reciente. Se ha comprobado, además, la capacidad de las trampas de caída y de succión para describir la composición faunística y la riqueza de especies según distintos grupos taxonómicos y ecológicos. Teniendo en cuenta el porcentaje de especies colectado sobre el total estimado, ambas técnicas de muestreo resultaron fiables en lo que se refiere a su eficacia, ofreciendo buenas estimas de la riqueza de especies de artrópodos. Usando los dos métodos a la vez, se obtuvieron valores de eficacia cercanos al 90% para algunos grupos taxonómicos. Las técnicas de succión o de caída por separado fueron fiables para estimar la riqueza de especies de artrópodos predadores (todas las especies) y arañas. Sin embargo, ambas técnicas son necesarias para conseguir estimaciones fiables en el caso de los grupos herbívoros. En términos de presencia-ausencia, los grupos que se alimentan de savia, los chupadores y los herbívoros masticadores mostraron diferentes patrones, con una proporción de colecta más alta en los primeros mediante las técnicas de succión, mientras que la mayoría de las especies masticadoras se pudieron colectar mediante las trampas de caída. Un patrón similar fue obtenido en el caso de las arañas, en donde las especies tejedoras fueron colectadas solo gracias a las técnicas de succión, mientras que la mayoría del resto de las especies se capturaron gracias al uso de trampas de caída. Se concluye que estos dos métodos de colecta deben considerarse complementarios y no alternativos. Por tanto, en estudios realizados en pastizales y sistemas agrícolas, se recomienda el uso simultáneo de ambas técnicas a fin de obtener estimas fiables de la riqueza de especies y la composición taxonómica de artrópodos