178 research outputs found
Examination of the temporal variation of peptide content in decomposition fluid under controlled conditions using pigs as human substitutes
We report the preliminary observations of the peptide content of decomposition fluid produced under controlled laboratory conditions and in the absence of a soil matrix. Four domestic pig (Sus scrofa domesticus) cadavers were used to model human decomposition over a four-week trial period; physical characteristics were recorded and the peptide components of decomposition fluid was analysed using high performance liquid chromatography-time of flight mass spectrometry. Preliminary data analysis indicated that a range of peptides were consistently detected across the course of the trial period and 27 of these were common to all four cadavers; 22 originating from haemoglobin. The peptides associated with haemoglobin subunit alpha and beta displayed a breakdown pattern that remained consistent for all cadavers for the duration of the trial. Though identification of peptides during decomposition has potential for estimating the time since death, quantification of selected peptides is likely to be essential to identify time-dependent trends
New records of marine invertebrates from Ascension Island (central Atlantic)
The sea anemone Telmatactis forskalii, the zoanthid Isaurus tuberculatus, the nemertine Baseodiscus delineatus, the echinoderms Ophiocoma wendtii and Mithrodia clavigera, the molluscs Colubraria canariensis, Glyphepithema turtoni, Tonna pennata, Trivia candidula, Melanella eburnea, Melanella n.sp., Echineulima leucophaes, Stylocheilus striatus, Limaria hians, Pteria hirundo and Callistoctopus macropus, and the crustaceans Tetraclitella sp., Oxynaspis celata, Thor amboinensis and Parribacus antarcticus are recorded from Ascension Island for the first time. A new depth record is given for the sea anemone Telmatactis cricoides. An undescribed shrimp species of the genus Lysmata and the shrimp Lysmata moorei were observed to clean fish at night.info:eu-repo/semantics/publishedVersio
Naked singularities in cylindrical collapse of counterrotating dust shells
Solutions describing the gravitational collapse of asymptotically flat cylindrical and prolate shells of (null) dust are shown to admit globally naked singularities
Complete genome sequence of the Medicago microsymbiont Ensifer (Sinorhizobium) medicae strain WSM419
Ensifer (Sinorhizobium) medicae is an effective nitrogen fixing microsymbiont of a diverse range of annual Medicago (medic) species. Strain WSM419 is an aerobic, motile, non-spore forming, Gram-negative rod isolated from a M. murex root nodule collected in Sardinia, Italy in 1981. WSM419 was manufactured commercially in Australia as an inoculant for annual medics during 1985 to 1993 due to its nitrogen fixation, saprophytic competence and acid tolerance properties. Here we describe the basic features of this organism, together with the complete genome sequence, and annotation. This is the first report of a complete genome se-quence for a microsymbiont of the group of annual medic species adapted to acid soils. We reveal that its genome size is 6,817,576 bp encoding 6,518 protein-coding genes and 81 RNA only encoding genes. The genome contains a chromosome of size 3,781,904 bp and 3 plasmids of size 1,570,951 bp, 1,245,408 bp and 219,313 bp. The smallest plasmid is a fea-ture unique to this medic microsymbiont
Quasars and their host galaxies
This review attempts to describe developments in the fields of quasar and
quasar host galaxies in the past five. In this time period, the Sloan and 2dF
quasar surveys have added several tens of thousands of quasars, with Sloan
quasars being found to z>6. Obscured, or partially obscured quasars have begun
to be found in significant numbers. Black hole mass estimates for quasars, and
our confidence in them, have improved significantly, allowing a start on
relating quasar properties such as radio jet power to fundamental parameters of
the quasar such as black hole mass and accretion rate. Quasar host galaxy
studies have allowed us to find and characterize the host galaxies of quasars
to z>2. Despite these developments, many questions remain unresolved, in
particular the origin of the close relationship between black hole mass and
galaxy bulge mass/velocity dispersion seen in local galaxies.Comment: Review article, to appear in Astrophysics Update
The Similarity Hypothesis in General Relativity
Self-similar models are important in general relativity and other fundamental
theories. In this paper we shall discuss the ``similarity hypothesis'', which
asserts that under a variety of physical circumstances solutions of these
theories will naturally evolve to a self-similar form. We will find there is
good evidence for this in the context of both spatially homogenous and
inhomogeneous cosmological models, although in some cases the self-similar
model is only an intermediate attractor. There are also a wide variety of
situations, including critical pheneomena, in which spherically symmetric
models tend towards self-similarity. However, this does not happen in all cases
and it is it is important to understand the prerequisites for the conjecture.Comment: to be submitted to Gen. Rel. Gra
Very-high energy gamma-ray astronomy: A 23-year success story in high-energy astroparticle physics
Very-high energy (VHE) gamma quanta contribute only a minuscule fraction -
below one per million - to the flux of cosmic rays. Nevertheless, being neutral
particles they are currently the best "messengers" of processes from the
relativistic/ultra-relativistic Universe because they can be extrapolated back
to their origin. The window of VHE gamma rays was opened only in 1989 by the
Whipple collaboration, reporting the observation of TeV gamma rays from the
Crab nebula. After a slow start, this new field of research is now rapidly
expanding with the discovery of more than 150 VHE gamma-ray emitting sources.
Progress is intimately related with the steady improvement of detectors and
rapidly increasing computing power. We give an overview of the early attempts
before and around 1989 and the progress after the pioneering work of the
Whipple collaboration. The main focus of this article is on the development of
experimental techniques for Earth-bound gamma-ray detectors; consequently, more
emphasis is given to those experiments that made an initial breakthrough rather
than to the successors which often had and have a similar (sometimes even
higher) scientific output as the pioneering experiments. The considered energy
threshold is about 30 GeV. At lower energies, observations can presently only
be performed with balloon or satellite-borne detectors. Irrespective of the
stormy experimental progress, the success story could not have been called a
success story without a broad scientific output. Therefore we conclude this
article with a summary of the scientific rationales and main results achieved
over the last two decades.Comment: 45 pages, 38 figures, review prepared for EPJ-H special issue "Cosmic
rays, gamma rays and neutrinos: A survey of 100 years of research
Fitting the integrated Spectral Energy Distributions of Galaxies
Fitting the spectral energy distributions (SEDs) of galaxies is an almost
universally used technique that has matured significantly in the last decade.
Model predictions and fitting procedures have improved significantly over this
time, attempting to keep up with the vastly increased volume and quality of
available data. We review here the field of SED fitting, describing the
modelling of ultraviolet to infrared galaxy SEDs, the creation of
multiwavelength data sets, and the methods used to fit model SEDs to observed
galaxy data sets. We touch upon the achievements and challenges in the major
ingredients of SED fitting, with a special emphasis on describing the interplay
between the quality of the available data, the quality of the available models,
and the best fitting technique to use in order to obtain a realistic
measurement as well as realistic uncertainties. We conclude that SED fitting
can be used effectively to derive a range of physical properties of galaxies,
such as redshift, stellar masses, star formation rates, dust masses, and
metallicities, with care taken not to over-interpret the available data. Yet
there still exist many issues such as estimating the age of the oldest stars in
a galaxy, finer details ofdust properties and dust-star geometry, and the
influences of poorly understood, luminous stellar types and phases. The
challenge for the coming years will be to improve both the models and the
observational data sets to resolve these uncertainties. The present review will
be made available on an interactive, moderated web page (sedfitting.org), where
the community can access and change the text. The intention is to expand the
text and keep it up to date over the coming years.Comment: 54 pages, 26 figures, Accepted for publication in Astrophysics &
Space Scienc
TRY plant trait database â enhanced coverage and open access
Plant traitsâthe morphological, anatomical, physiological, biochemical and phenological characteristics of plantsâdetermine how plants respond to environmental factors, affect other trophic levels, and influence ecosystem properties and their benefits and detriments to people. Plant trait data thus represent the basis for a vast area of research spanning from evolutionary biology, community and functional ecology, to biodiversity conservation, ecosystem and landscape management, restoration, biogeography and earth system modelling. Since its foundation in 2007, the TRY database of plant traits has grown continuously. It now provides unprecedented data coverage under an open access data policy and is the main plant trait database used by the research community worldwide. Increasingly, the TRY database also supports new frontiers of traitâbased plant research, including the identification of data gaps and the subsequent mobilization or measurement of new data. To support this development, in this article we evaluate the extent of the trait data compiled in TRY and analyse emerging patterns of data coverage and representativeness. Best species coverage is achieved for categorical traitsâalmost complete coverage for âplant growth formâ. However, most traits relevant for ecology and vegetation modelling are characterized by continuous intraspecific variation and traitâenvironmental relationships. These traits have to be measured on individual plants in their respective environment. Despite unprecedented data coverage, we observe a humbling lack of completeness and representativeness of these continuous traits in many aspects. We, therefore, conclude that reducing data gaps and biases in the TRY database remains a key challenge and requires a coordinated approach to data mobilization and trait measurements. This can only be achieved in collaboration with other initiatives
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