Allelic richness and diversity in global composite collection and reference sets in chickpea (Cicer arietinum L.)

Chickpea is the fourth largest grain legume crop globally. A composite collection of 3000 accessions was formed and genotyped using 50 SSR markers. The accessions were also field evaluated for seven qualitative traits. Analysis of 48 SSR markers data on 2915 accessions detected 1683 alleles, of which 935 were rare and 748 common. Gene diversity varied from 0.533 to 0.975. Kabuli chickpea as a group were genetically more diverse than other seed types. Several group-specific unique alleles were detected: 104 in Kabuli, 297 in desi, and 69 in wild Cicer; 114 each in West Asia and Mediterranean, 117 in South and South East Asia, and 10 in African region accessions. A genotype-based reference set captured 1315 alleles compared to 1237 alleles in the reference set based on qualitative traits or 1354 alleles based on SSRs and qualitative traits data. The relative usefulness of these reference sets in chickpea breeding and genomics studies are being further investigated

Predictions from Quantum Cosmology

The world view suggested by quantum cosmology is that inflating universes with all possible values of the fundamental constants are spontaneously created out of nothing. I explore the consequences of the assumption that we are a `typical' civilization living in this metauniverse. The conclusions include inflation with an extremely flat potential and low thermalization temperature, structure formation by topological defects, and an appreciable cosmological constant.Comment: (revised version), 15 page

Categorizing Different Approaches to the Cosmological Constant Problem

We have found that proposals addressing the old cosmological constant problem come in various categories. The aim of this paper is to identify as many different, credible mechanisms as possible and to provide them with a code for future reference. We find that they all can be classified into five different schemes of which we indicate the advantages and drawbacks. Besides, we add a new approach based on a symmetry principle mapping real to imaginary spacetime.Comment: updated version, accepted for publicatio

Dark Energy and Gravity

I review the problem of dark energy focusing on the cosmological constant as the candidate and discuss its implications for the nature of gravity. Part 1 briefly overviews the currently popular `concordance cosmology' and summarises the evidence for dark energy. It also provides the observational and theoretical arguments in favour of the cosmological constant as the candidate and emphasises why no other approach really solves the conceptual problems usually attributed to the cosmological constant. Part 2 describes some of the approaches to understand the nature of the cosmological constant and attempts to extract the key ingredients which must be present in any viable solution. I argue that (i)the cosmological constant problem cannot be satisfactorily solved until gravitational action is made invariant under the shift of the matter lagrangian by a constant and (ii) this cannot happen if the metric is the dynamical variable. Hence the cosmological constant problem essentially has to do with our (mis)understanding of the nature of gravity. Part 3 discusses an alternative perspective on gravity in which the action is explicitly invariant under the above transformation. Extremizing this action leads to an equation determining the background geometry which gives Einstein's theory at the lowest order with Lanczos-Lovelock type corrections. (Condensed abstract).Comment: Invited Review for a special Gen.Rel.Grav. issue on Dark Energy, edited by G.F.R.Ellis, R.Maartens and H.Nicolai; revtex; 22 pages; 2 figure

A Galaxy-scale Fountain of Cold Molecular Gas Pumped by a Black Hole

We present Atacama Large Millimeter/submillimeter Array and Multi-Unit Spectroscopic Explorer observations of the brightest cluster galaxy in Abell 2597, a nearby (z = 0.0821) cool core cluster of galaxies. The data map the kinematics of a three billion solar mass filamentary nebula that spans the innermost 30 kpc of the galaxy's core. Its warm ionized and cold molecular components are both cospatial and comoving, consistent with the hypothesis that the optical nebula traces the warm envelopes of many cold molecular clouds that drift in the velocity field of the hot X-ray atmosphere. The clouds are not in dynamical equilibrium, and instead show evidence for inflow toward the central supermassive black hole, outflow along the jets it launches, and uplift by the buoyant hot bubbles those jets inflate. The entire scenario is therefore consistent with a galaxy-spanning "fountain," wherein cold gas clouds drain into the black hole accretion reservoir, powering jets and bubbles that uplift a cooling plume of low-entropy multiphase gas, which may stimulate additional cooling and accretion as part of a self-regulating feedback loop. All velocities are below the escape speed from the galaxy, and so these clouds should rain back toward the galaxy center from which they came, keeping the fountain long lived. The data are consistent with major predictions of chaotic cold accretion, precipitation, and stimulated feedback models, and may trace processes fundamental to galaxy evolution at effectively all mass scales

Raining in MKW 3 s: a Chandra-MUSE analysis of X-Ray cold filaments around 3CR 318.1

High Energy Astrophysic