The conditional benefits of cannibalism for wood frog tadpoles (lithobates sylvaticus)

Wood frog tadpoles have an incredible ability to rapidly adapt to changing conditions, and when population densities become high tadpoles often become cannibalistic. Cannibalism potentially represents an ideal diet by composition, and should be beneficial to the growth and development of cannibalistic individuals. To test the relative efficacy of cannibalism to growth and development we conducted multiple feeding experiments. Results indicate that cannibalism represents a better alternative to starvation and provides some benefit to development and survival of tadpoles over low quality diets. However, cannibalism can be detrimental to tadpole growth and/or develop­ment relative to diets of similar protein content. Additionally, tadpoles raised individually appear to initially avoid consuming the cannibalistic diet, and may continue to do so until they face the risk of starvation. Conversely, when tadpoles were raised in groups providing them with compe­tition, they immediately fed upon the cannibal diet. Our results suggest that competition, rather than dietary quality is likely the driving force behind cannibalistic behaviour unless tadpoles oth­erwise face the risk of starvation

Triplet superconductivity in quasi one-dimensional systems

We study a Hubbard hamiltonian, including a quite general nearest-neighbor interaction, parametrized by repulsion V, exchange interactions Jz, Jperp, bond-charge interaction X and hopping of pairs W. The case of correlated hopping, in which the hopping between nearest neighbors depends upon the occupation of the two sites involved, is also described by the model for sufficiently weak interactions. We study the model in one dimension with usual continuum-limit field theory techniques, and determine the phase diagram. For arbitrary filling, we find a very simple necessary condition for the existence of dominant triplet superconducting correlations at large distance in the spin SU(2) symmetric case: 4V+J<0. In the correlated hopping model, the three-body interaction should be negative for positive V. We also compare the predictions of this weak-coupling treatment with numerical exact results for the correlated-hopping model obtained by diagonalizing small chains, and using novel techniques to determine the opening of the spin gap.Comment: 8 pages, 3 figure

Optical symmetries and anisotropic transport in high-Tc superconductors

A simple symmetry analysis of in-plane and out-of-plane transport in a family of high temperature superconductors is presented. It is shown that generalized scaling relations exist between the low frequency electronic Raman response and the low frequency in-plane and out-of-plane conductivities in both the normal and superconducting states of the cuprates. Specifically, for both the normal and superconducting state, the temperature dependence of the low frequency $B_{1g}$ Raman slope scales with the $c-$axis conductivity, while the $B_{2g}$ Raman slope scales with the in-plane conductivity. Comparison with experiments in the normal state of Bi-2212 and Y-123 imply that the nodal transport is largely doping independent and metallic, while transport near the BZ axes is governed by a quantum critical point near doping $p\sim 0.22$ holes per CuO$_{2}$ plaquette. Important differences for La-214 are discussed. It is also shown that the $c-$ axis conductivity rise for $T\ll T_{c}$ is a consequence of partial conservation of in-plane momentum for out-of-plane transport.Comment: 16 pages, 8 Figures (3 pages added, new discussion on pseudogap and charge ordering in La214

Agronomic potential of genebank landrace elite accessions for common bean genetic breeding

Plant breeding efficiency relies mainly on genetic diversity and selection to release new cultivars. This study aimed to identify landraces with favorable characteristics that can be used as parents of segregating populations in common bean (Phaseolus vulgaris L.) breeding programs. Firstly, ten bean genotypes were selected because they showed promising agronomic performance, and the following seven adaptive traits of four commercial bean cultivars were evaluated: i) plant height; ii) diameter of the stem; iii) height of the insertion of the first pod; iv) pod number per plant; v) grain number per pod; vi) weight of a thousand grains and vii) grain yield. The accessions BAF 07, BAF 44, and BAF 45 are promising in terms of increasing plant height, and accession BAF 01, in terms of reducing plant height. The accession BAF 07 was also the most promising in terms of a plant ideotype that combines higher plant height, maximum height of the insertion of the first pod, and increment in grain yield. Moreover, the selection can be made between and within accessions, because genetic variability is also present within landraces

The status of the world's land and marine mammals: diversity, threat, and knowledge

Knowledge of mammalian diversity is still surprisingly disparate, both regionally and taxonomically. Here, we present a comprehensive assessment of the conservation status and distribution of the world's mammals. Data, compiled by 1700+ experts, cover all 5487 species, including marine mammals. Global macroecological patterns are very different for land and marine species but suggest common mechanisms driving diversity and endemism across systems. Compared with land species, threat levels are higher among marine mammals, driven by different processes (accidental mortality and pollution, rather than habitat loss), and are spatially distinct (peaking in northern oceans, rather than in Southeast Asia). Marine mammals are also disproportionately poorly known. These data are made freely available to support further scientific developments and conservation action

Size Doesn't Matter: Towards a More Inclusive Philosophy of Biology

notes: As the primary author, O’Malley drafted the paper, and gathered and analysed data (scientific papers and talks). Conceptual analysis was conducted by both authors.publication-status: Publishedtypes: ArticlePhilosophers of biology, along with everyone else, generally perceive life to fall into two broad categories, the microbes and macrobes, and then pay most of their attention to the latter. ‘Macrobe’ is the word we propose for larger life forms, and we use it as part of an argument for microbial equality. We suggest that taking more notice of microbes – the dominant life form on the planet, both now and throughout evolutionary history – will transform some of the philosophy of biology’s standard ideas on ontology, evolution, taxonomy and biodiversity. We set out a number of recent developments in microbiology – including biofilm formation, chemotaxis, quorum sensing and gene transfer – that highlight microbial capacities for cooperation and communication and break down conventional thinking that microbes are solely or primarily single-celled organisms. These insights also bring new perspectives to the levels of selection debate, as well as to discussions of the evolution and nature of multicellularity, and to neo-Darwinian understandings of evolutionary mechanisms. We show how these revisions lead to further complications for microbial classification and the philosophies of systematics and biodiversity. Incorporating microbial insights into the philosophy of biology will challenge many of its assumptions, but also give greater scope and depth to its investigations