Phylogenetic diversity and evolutionary distinctiveness of Amazonian floodplain forest birds

The Amazon basin contains one-fifth of all free-flowing fresh water on the planet and is home to the largest tropical rainforest on Earth. However, the region is not homogenous and is interspersed with several different forest types. Floodplain forests are formed from the seasonal rainfall that spills over the banks of the rivers and inundate vast areas. In the Amazon basin, várzea are formed from the whitewater rivers that carry sediment eroded from the Andes and deposited on the floodplains. They are the most fertile of the floodplain forest types. Forests inundated on a seasonal basis by either black- or clear-water rivers are collectively known as igapó. They are of lower fertility than várzea. The differences in floristic composition of the floodplain forests affects the faunal composition. There is a high species richness of birds in the floodplain forests due to the availability of resources such as fruits, flowers, insects, habitat niches and special foraging substrates. To examine the richness, I used the indices of Phylogenetic Diversity to calculate the amount of evolutionary history and Evolutionary Distinctiveness, to find the most evolutionarily unique species from a compiled list of floodplain forest bird species. The results show that the seasonally flooded forests contain some species of very early origin and many species of more recent origin. Species that have a long evolutionary history are some of the most evolutionarily unique species and are the only representatives of a single family. This therefore offers an opportunity to examine if conservation efforts are sufficiently protecting evolutionarily unique species. Disturbance of the flood pulse in the Amazonian floodplains through infrastructure development (e.g., hydroelectric dams) or global climate change (in the form of extreme floods or droughts) can pose a serious threat to the ecology of the seasonally flooded forests across Amazonia. There is, therefore, a pressing need to better our understanding of biodiversity patterns and community assemblages across the Amazonian floodplains.M-ECO

LDPC Codes Which Can Correct Three Errors Under Iterative Decoding

In this paper, we provide necessary and sufficient conditions for a column-weight-three LDPC code to correct three errors when decoded using Gallager A algorithm. We then provide a construction technique which results in a code satisfying the above conditions. We also provide numerical assessment of code performance via simulation results.Comment: 5 pages, 3 figures, submitted to IEEE Information Theory Workshop (ITW), 200

LOZENGE TILING CONSTRAINED CODES

While the field of one-dimensional constrained codesis mature, with theoretical as well as practical aspects of codeanddecoder-design being well-established, such a theoreticaltreatment of its two-dimensional (2D) counterpart is still unavailable.Research has been conducted on a few exemplar2D constraints, e.g., the hard triangle model, run-length limitedconstraints on the square lattice, and 2D checkerboardconstraints. Excluding these results, 2D constrained systemsremain largely uncharacterized mathematically, with only loosebounds of capacities present. In this paper we present a lozengeconstraint on a regular triangular lattice and derive Shannonnoiseless capacity bounds. To estimate capacity of lozenge tilingwe make use of the bijection between the counting of lozengetiling and the counting of boxed plane partitions

Development of 3D Angle-Interlock Woven Preforms for Composites

The advent of three dimensional (3D) reinforcements has been mainly to overcome the issue of delamination and improve upon the damage tolerance properties by introducing fibres in the thickness direction for advanced composite applications. 3D preforms can be developed using various techniques. Angle-interlock weaving is one of them. This paper details about the efforts being put at CSIR-NAL for developing angle-interlock woven preforms. Four types of angle-interlock structures viz., layer-to-layer and through thickness (both with and without stuffer yarns) were developed using 6K, 400 Tex TC-33 grade Carbon tows on a custom designed handloom. The preforms without stuffer yarns had 4 layers of warp and were of 1.5± 0.2 mm thick. Preforms with stuffer yarns had 6 layers of warp (including 2 stuffer yarn layers) and were of 2.3±0.1 mm thick. Thermoset composites were prepared from these preforms using EPOLAM 2063 (an epoxy based resin system) by RTM process. The fibre weight fraction for these composites ranged from 0.53 to 0.58 and they were subjected to mechanical tests such as tensile, flexural and interlaminar shear strength. Test results showed improved response (in the warp direction) with respect to shear properties while the tensile and flexural properties were equivalent to that of the plain woven composites

Hartman effect in presence of Aharanov Bohm flux

The Hartman effect for the tunneling particle implies the independence of group delay time on the opaque barrier width, with superluminal velocities as a consequence. This effect is further examined on a quantum ring geometry in the presence of Aharonov-Bohm flux. We show that while tunneling through an opaque barrier the group delay time for given incident energy becomes independent of the barrier thickness as well as the magnitude of the flux. The Hartman effect is thereby extended beyond one dimension and in the presence of Aharonov-Bohm flux.Comment: 4 pages, 4 figure