1,140 research outputs found
Genetic structure of pike (Esox lucius) reveals a complex and previously unrecognized colonization history of Ireland
Aim: We investigated genetic variation of Irish pike populations and their relationship with European outgroups, in order to elucidate the origin of this species to the island, which is largely assumed to have occurred as a human-mediated introduction over the past few hundred years. We aimed thereby to provide new insights into population structure to improve fisheries and biodiversity management in Irish freshwaters.
Location: Ireland, Britain and continental Europe.
Methods: A total of 752 pike (Esox lucius) were sampled from 15 locations around Ireland, and 9 continental European sites, and genotyped at six polymorphic microsatellite loci. Patterns and mechanisms of population genetic structure were assessed through a diverse array of methods, including Bayesian clustering, hierarchical analysis of molecular variance, and approximate Bayesian computation.
Results: Varying levels of genetic diversity and a high degree of population genetic differentiation were detected. Clear substructure within Ireland was identified, with two main groups being evident. One of the Irish populations showed high similarity with British populations. The other, more widespread, Irish strain did not group with any European population examined. Approximate Bayesian computation suggested that this widespread Irish strain is older, and may have colonized Ireland independently of humans.
Main conclusions: Population genetic substructure in Irish pike is high and comparable to the levels observed elsewhere in Europe. A comparison of evolutionary scenarios upholds the possibility that pike may have colonized Ireland in two âwavesâ, the first of which, being independent of human colonization, would represent the first evidence for natural colonization of a non-anadromous 42 freshwater fish to the island of Ireland. Although further investigations using comprehensive genomic techniques will be necessary to confirm this, the present results warrant a reappraisal of current management strategies for this species
Effect of Pre-and Post-weaning Nutrition and Management on Performance of Weaned Pigs to circa 35 kg.
End of Project ReportThe objective of this project was to examine the factors
affecting performance (growth rate, appetite, feed conversion efficiency)
of pigs in the stage from weaning to 35 kg liveweight.
The study involved three stages, creep feeding during the suckling
period, management during the first weaner stage (c. 4 weeks
from weaning or 6 kg to 15 kg liveweight) and management during
the second weaner stage (c. 15 kg to 35 kg liveweight.
Creep feed intake before weaning was low c. 2.5 to 3.0 kg
per litter but where it was consumed the response in terms of feed
conversion efficiency was good with litter weight increasing in
weight by about 1.1 kg for each 1 kg creep consumed. Milk
replacer in liquid form was very readily consumed but its preparation
and feeding is very laborious. Weaning weight was poorly
related to post weaning performance and weaning age seemed to
be more critical which is probably a reflection of the greater
maturity of older animals.
In the first weaner stage, feeding of cooked cereal containing
diets was found to have little benefit in pig performance.
Acidification of feeds is likely to have only a minor influence on
pig performance. An experiment on choice feeding of starter and
link feeds did not confirm that smaller pigs require a higher quality
diet and, in a choice situation will eat a greater proportion of the
more nutrient dense diet.
In the second weaner stage, comparison of three commercial
weaner feeds with a cereal based control diet showed good performance
on all four diets. Pigs fed a high lysine weaner diet grew
better in the weaner stage but by slaughter those pigs fed the low
lysine weaner diet, after all pigs were fed a common finisher diet,
had overtaken them. The high lysine group did, however, have
leaner carcasses.
Residual effects of early nutrition need to be investigated in
more detail including the effect of pregnancy feeding on prenatal
development and the relationship between prenatal growth and
postnatal growth, in particular development of muscle.European Union Structural Funds (EAGGF
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NONDESTRUCTIVE IDENTIFICATION OF CHEMICAL WARFARE AGENTS AND EXPLOSIVES BY NEUTRON GENERATOR-DRIVEN PGNAA
Prompt gamma-ray neutron activation analysis (PGNAA) is now a proven method for the identification of chemical warfare agents and explosives in military projectiles and storage containers. Idaho National Laboratory is developing a next-generation PGNAA instrument based on the new Ortec Detective mechanically-cooled HPGe detector and a neutron generator. In this paper we review PGNAA analysis of suspect chemical warfare munitions, and we discuss the advantages and disadvantages of replacing the californium-252 radioisotopic neutron source with a compact accelerator neutron generator
Tissue-specific expression of high-voltage-activated dihydropyridine-sensitive L-type calcium channels
The cloning of the cDNA for the α1 subunit of L-type calcium channels revealed that at least two genes (CaCh1 and CaCh2) exist which give rise to several splice variants. The expression of mRNA for these α1 subunits and the skeletal muscle α2/ÎŽ, ÎČ and Îł subunits was studied in rabbit tissues and BC3H1 cells. Nucleic-acid-hybridization studies showed that the mRNA of all subunits are expressed in skeletal muscle, brain, heart and aorta. However, the α1-, ÎČ- and Îł-specific transcripts had different sizes in these tissues. Smooth muscle and heart contain different splice variants of the CaCh2 gene. The α1, ÎČ and Îł mRNA are expressed together in differentiated but not in proliferating BC3H1 cells. A probe specific for the skeletal muscle α2/ÎŽ subunit did not hybridize to poly(A)-rich RNA from BC3H1 cells. These results suggest that different splice variants of the genes for the α1, ÎČ and Îł subunits exist in tissues containing L-type calcium channels, and that their expression is regulated in a coordinate manner
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A Comparison of Neutron-Based Non-Destructive Assessment Methods for Chemical Warfare Materiel and High Explosives
Prompt Gamma Neutron Activation Analysis (PGNAA) systems employ neutrons as a probe to interrogate items, e.g. chemical warfare materiel-filled munitions. The choice of a neutron source in field-portable systems is determined by its ability to excite nuclei of interest, operational concerns such as radiological safety and ease-of-use, and cost. Idaho National Laboratoryâs PINS Chemical Assay System has traditionally used a Cf-252 isotopic neutron source, but recently a Deuterium-Tritium (DT) Electronic Neutron Generator (ENG) has been tested as an alternate neutron source. This paper presents the results of using both of these neutron sources to interrogate chemical warfare materiel (CWM) and high explosive (HE) filled munitions
A History of common carp Cyprinus carpio (L.) in Ireland: A Review
This paper represents the most comprehensive and detailed summary of the history of
common carp Cyprinus carpio (L.) in Ireland to date. It charts the earliest known
introductions of the species to Irish waters, the rise in popularity of recreational angling
for the species from c. 1950 onwards, the work carried out to establish the species in
Ireland and explains the primary causes of their more recent distribution increase.
Much of the historical research material gathered on common carp in Irish waters,
including the first recorded details of introduction, is presented here for the first time.Funder: Marine Institut
FloquetâBloch solutions in a sawtooth photonic crystal
Band structure of a sawtooth photonic crystal for optical wave propagation along the axis of periodicity is investigated. Floquet-Bloch solutions are found and illustrated for the bandgaps, allowed bands, and bandedges of the crystal. Special attention is given to the cases where Floquet-Bloch solutions become periodic functions
Pressure Induced Hydration Dynamics of Membranes
Pressure-jump initiated time-resolved x-ray diffraction studies of dynamics
of the hydration of the hexagonal phase in biological membranes show that (i)
the relaxation of the unit cell spacing is non-exponential in time; (ii) the
Bragg peaks shift smoothly to their final positions without significant
broadening or loss in crystalline order. This suggests that the hydration is
not diffusion limited but occurs via a rather homogeneous swelling of the whole
lattice, described by power law kinetics with an exponent .Comment: REVTEX 3, 10 pages,3 figures(available on request),#
A Compensatory Mutation Provides Resistance to Disparate HIV Fusion Inhibitor Peptides and Enhances Membrane Fusion
Fusion inhibitors are a class of antiretroviral drugs used to prevent entry of HIV into host cells. Many of the fusion inhibitors being developed, including the drug enfuvirtide, are peptides designed to competitively inhibit the viral fusion protein gp41. With the emergence of drug resistance, there is an increased need for effective and unique alternatives within this class of antivirals. One such alternative is a class of cyclic, cationic, antimicrobial peptides known as Ξ-defensins, which are produced by many non-human primates and exhibit broad-spectrum antiviral and antibacterial activity. Currently, the Ξ-defensin analog RC-101 is being developed as a microbicide due to its specific antiviral activity, lack of toxicity to cells and tissues, and safety in animals. Understanding potential RC-101 resistance, and how resistance to other fusion inhibitors affects RC-101 susceptibility, is critical for future development. In previous studies, we identified a mutant, R5-tropic virus that had evolved partial resistance to RC-101 during in vitro selection. Here, we report that a secondary mutation in gp41 was found to restore replicative fitness, membrane fusion, and the rate of viral entry, which were compromised by an initial mutation providing partial RC-101 resistance. Interestingly, we show that RC-101 is effective against two enfuvirtide-resistant mutants, demonstrating the clinical importance of RC-101 as a unique fusion inhibitor. These findings both expand our understanding of HIV drug-resistance to diverse peptide fusion inhibitors and emphasize the significance of compensatory gp41 mutations. © 2013 Wood et al
A systems approach to policy evaluation
There is growing interest in evaluating policy implementation in ways that grapple with the complexity of the process. This article offers an example of using systems methodology to explore how the child protection policy in child contact centres has functioned in practice. Rather than just asking the traditional evaluation question âis it working?â this study sought to understand how the policy was working and how it was interpreted as it interacted with other systems, producing conflicts, local variation and emergent effects. It illustrates how the systems concepts of âemergenceâ, âlocal rationalityâ, âsocio-technical systemsâ and âfeedback for learningâ can contribute new knowledge and understanding to a complex policy evaluation problem
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