1,432 research outputs found
Morphological evolution in Hyles Hübner, 1819 hawkmoths (Lepidoptera, Sphingidae): reconstructing the ancestral Hyles habitus
Molecular phylogenetic studies suggest that similar wing and body patterns in the hawkmoth genus Hyles Hübner, [1819] do not necessarily reflect a close phylogenetic relationship. To improve our understanding of morphological evolution in these organisms, 75 characters derived from the external adult morphology are explicitly coded and analysed in a maximum parsimony cladistic framework. The results corroborate the hypothesis that wing and body patterns have indeed reappeared in different parts of the phylogeny but the underlying genetic mechanism remains to be determined. By reconstructing the suite of ancestral states of the morphological characters using Bayesian inference, we derived an approximation of the appearance of the proto-Hyles species. The overall habitus of this moth does not display a combination of characters found in any extant Hyles species. Rather, the forewings are most like those of members of the Hyles euphorbiae-complex but with better developed antemedial and postmedial lines, the hindwings are typical Hyles, and the abdominal pattern most closely resembles that of Hyles euphorbiarum (Guérin-Méneville & Percheron, 1835), but with one fewer pairs of black subdorsal patches. Within the context of the subtribe Choerocampina and Sphingidae more generally, the proto-Hyles reconstruction does not resemble any other species apart from Rhodafra opheltes (Cramer, 1780), but this appears to be another instance of convergent pattern expression
Weak gravitational lensing with the Square Kilometre Array
We investigate the capabilities of various stages of the SKA to perform
world-leading weak gravitational lensing surveys. We outline a way forward to
develop the tools needed for pursuing weak lensing in the radio band. We
identify the key analysis challenges and the key pathfinder experiments that
will allow us to address them in the run up to the SKA. We identify and
summarize the unique and potentially very powerful aspects of radio weak
lensing surveys, facilitated by the SKA, that can solve major challenges in the
field of weak lensing. These include the use of polarization and rotational
velocity information to control intrinsic alignments, and the new area of weak
lensing using intensity mapping experiments. We show how the SKA lensing
surveys will both complement and enhance corresponding efforts in the optical
wavebands through cross-correlation techniques and by way of extending the
reach of weak lensing to high redshift.Comment: 19 pages, 6 figures. Cosmology Chapter, Advancing Astrophysics with
the SKA (AASKA14) Conference, Giardini Naxos (Italy), June 9th-13th 201
A filament of dark matter between two clusters of galaxies
It is a firm prediction of the concordance Cold Dark Matter (CDM)
cosmological model that galaxy clusters live at the intersection of large-scale
structure filaments. The thread-like structure of this "cosmic web" has been
traced by galaxy redshift surveys for decades. More recently the Warm-Hot
Intergalactic Medium (WHIM) residing in low redshift filaments has been
observed in emission and absorption. However, a reliable direct detection of
the underlying Dark Matter skeleton, which should contain more than half of all
matter, remained elusive, as earlier candidates for such detections were either
falsified or suffered from low signal-to-noise ratios and unphysical
misalignements of dark and luminous matter. Here we report the detection of a
dark matter filament connecting the two main components of the Abell 222/223
supercluster system from its weak gravitational lensing signal, both in a
non-parametric mass reconstruction and in parametric model fits. This filament
is coincident with an overdensity of galaxies and diffuse, soft X-ray emission
and contributes mass comparable to that of an additional galaxy cluster to the
total mass of the supercluster. Combined with X-ray observations, we place an
upper limit of 0.09 on the hot gas fraction, the mass of X-ray emitting gas
divided by the total mass, in the filament.Comment: Nature, in pres
Phylogenomics resolves major relationships and reveals significant diversification rate shifts in the evolution of silk moths and relatives
Background:
Silkmoths and their relatives constitute the ecologically and taxonomically diverse superfamily Bombycoidea,which includes some of the most charismatic species of Lepidoptera. Despite displaying spectacular forms and diverse ecological traits, relatively little attention has been given to understanding their evolution and drivers of their diversity. To begin to address this problem, we created a new Bombycoidea-specific Anchored Hybrid Enrichment (AHE) probe set and sampled up to 571 loci for 117 taxa across all major lineages of the Bombycoidea, with a newly developed DNA extraction protocol that allows Lepidoptera specimens to be readily sequenced from pinned natural history collections.
Results:
The well-supported tree was overall consistent with prior morphological and molecular studies, although some taxa were misplaced. The bombycid Arotros Schaus was formally transferred to Apatelodidae. We identified important evolutionary patterns (e.g., morphology, biogeography, and differences in speciation and extinction), and our analysis of diversification rates highlights the stark increases that exist within the Sphingidae (hawkmoths) and Saturniidae (wild silkmoths).
Conclusions:
Our study establishes a backbone for future evolutionary, comparative, and taxonomic studies of Bombycoidea. We postulate that the rate shifts identified are due to the well-documented bat-moth“arms race”.Our research highlights the flexibility of AHE to generate genomic data from a wide range of museum specimens, both age and preservation method, and will allow researchers to tap into the wealth of biological data residing in natural history collections around the globe
Experimental search for the decay mode K_L -> pi^0 gamma e^+ e^-
We report on results of a search for the decay mode K_L -> pi^0 gamma e^+ e^-
conducted by the E162 experiment at KEK. We observed no events and set a 90%
confidence level upper limit of Br(K_L -> pi^0 gamma e^+ e^-)< 7.1x10^{-7} for
its branching ratio. This is the first published experimental result on this
decay mode.Comment: 10 pages, 4 figures, submitted to Physics Letters
Nucleon-nucleon bremsstrahlung: An example of the impossibility of measuring off-shell amplitudes
For nearly fifty years theoretical and experimental efforts in
nucleon-nucleon bremsstrahlung (NN) have been devoted to measuring
off-shell amplitudes and distinguishing among various NN potentials on the
basis of their off-shell behavior. New experiments are underway, designed
specifically to attain kinematics further off shell than in the past, and thus
to be more sensitive to the off-shell behavior. This letter shows that,
contrary to these expectations, and due to the invariance of the S-matrix under
transformations of the fields, the off-shell NN amplitude is as a matter of
principle an unmeasurable quantity in NN.Comment: 9 pages, Latex, using RevTeX; Minor wording changes, title changed,
version to be published in Phys. Rev. Letter
Phylogenomics resolves major relationships and reveals significant diversification rate shifts in the evolution of silk moths and relatives
Background: Silkmoths and their relatives constitute the ecologically and taxonomically diverse superfamily Bombycoidea, which includes some of the most charismatic species of Lepidoptera. Despite displaying spectacular forms and diverse ecological traits, relatively little attention has been given to understanding their evolution and drivers of their diversity. To begin to address this problem, we created a new Bombycoidea-specific Anchored Hybrid Enrichment (AHE) probe set and sampled up to 571 loci for 117 taxa across all major lineages of the Bombycoidea, with a newly developed DNA extraction protocol that allows Lepidoptera specimens to be readily sequenced from pinned natural history collections. Results: The well-supported tree was overall consistent with prior morphological and molecular studies, although some taxa were misplaced. The bombycid Arotros Schaus was formally transferred to Apatelodidae. We identified important evolutionary patterns (e.g., morphology, biogeography, and differences in speciation and extinction), and our analysis of diversification rates highlights the stark increases that exist within the Sphingidae (hawkmoths) and Saturniidae (wild silkmoths). Conclusions: Our study establishes a backbone for future evolutionary, comparative, and taxonomic studies of Bombycoidea. We postulate that the rate shifts identified are due to the well-documented bat-moth “arms race”. Our research highlights the flexibility of AHE to generate genomic data from a wide range of museum specimens, both age and preservation method, and will allow researchers to tap into the wealth of biological data residing in natural history collections around the globe.Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.NHM Repositor
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