1,987 research outputs found
Higgs Boson Exempt No-Scale Supersymmetry with a Neutrino Seesaw: Implications for Lepton Flavor Violation and Leptogenesis
Motivated by the observation of neutrino oscillations, we extend the Higgs
boson exempt no-scale supersymmetry model (HENS) by adding three heavy
right-handed neutrino chiral supermultiplets to generate the light neutrino
masses and mixings. The neutrino Yukawa couplings can induce new lepton flavor
violating couplings among the soft terms in the course of renormalization group
running down from the boundary scale. We study the effects this has on the
predictions for low-energy probes of lepton flavor violation(LFV). Heavy
right-handed neutrinos also provide a way to generate the baryon asymmetry
through leptogenesis. We find that consistency with LFV and leptogenesis puts
strong requirements on either the form of the Yukawa mass matrix or the
smallness of the Higgs up soft mass. In all cases, we generically expect that
new physics LFV is non-zero and can be found in a future experiment.Comment: 25 pages, 11 figures; Added a referenc
Introducing SEARCHBreast: a virtual resource to facilitate sharing of surplus animal material developed for breast cancer research
Animals studies have made significant contribution to expanding our knowledge of breast cancer. Often material is leftover and archived. SEARCHBreast provides a platform for collaborative sharing of archived material via a dedicated on-line database whereby users can both share and search available tissue. The SEARCHBreast database has information on over 50 different mouse models, including tissue from PDX models, available to share. With thousands of samples freely available, SEARCHBreast should be the first point of call for any researcher looking for animal material to aid their breast cancer research
SEARCHBreast: A new online resource to make surplus material from in vivo models of breast cancer visible and accessible to researchers
No abstract available
SEARCHBreast: a new resource to locate and share surplus archival material from breast cancer animal models to help address the 3Rs
Animal models have contributed to our understanding
of breast cancer, with publication of results in
high-impact journals almost invariably requiring extensive
in vivo experimentation. As such, many laboratories hold
large collections of surplus animal material, with only a
fraction being used in publications relating to the original
projects. Despite being developed at considerable cost, this
material is an invisible and hence an underutilised
resource, which often ends up being discarded. Within the
breast cancer research community there is both a need and
desire to make this valuable material available for
researchers. Lack of a coordinated system for visualisation
and localisation of this has prevented progress. To fulfil
this unmet need, we have developed a novel initiative
called Sharing Experimental Animal Resources: Coordinating
HoldingsâBreast (SEARCHBreast) which facilitates
sharing of archival tissue between researchers on a
collaborative basis and, de facto will reduce overall usage
of animal models in breast cancer research. A secure
searchable database has been developed where researchers
can find, share, or upload materials related to animal
models of breast cancer, including genetic and transplant
models. SEARCHBreast is a virtual compendium where
the physical material remains with the original laboratory.
A bioanalysis pipeline is being developed for the analysis
of transcriptomics data associated with mouse models,
allowing comparative study with human and cell line data.
Additionally, SEARCHBreast is committed to promoting
the use of humanised breast tissue models as replacement
alternatives to animals. Access to this unique resource is freely available to all academic researchers following
registration at https://searchbreast.org
SEARCHBreast: An online resource designed to increase the efficiency of using materials derived from breast cancer studies in animals
No abstract available
The SEARCHBreast portal: A virtual bioresource to facilitate the sharing of surplus animal materials derived from breast cancer studies
The SEARCHBreast portal (https://searchbreast.org/) provides access to a virtual bioresource enabling researchers to access and share material derived from breast cancer related animal studies on a collaborative basis. By registering as members of SEARCHBreast, researchers can browse the SEARCHBreast platform for relevant tissue and models, and request access to these to help answer their specific biological question(s). SEARCHBreast mediates the collaborations formed from requests for these materials. As of July 2016, the virtual bioresource has received 8 requests for tissue and has sent hundreds of tissue samples saving approximately 400 animals. SEARCHBreast is currently developing a bioinformatics pipeline, enabling users to access and mine published data on animal models of breast cancer, potentially helping to reduce experimental redundancy further, prioritising new relevant research
Multivariate analysis of morphology, behaviour, growth and developmental timing in hybrids brings new insights into the divergence of sympatric Arctic charr morphs
This work was fully funded by the Icelandic Centre of Research, RANNĂS (Icelandic Research Fund grant no.173802-051).Background: Studying the development of fitness related traits in hybrids from populations diverging in sympatry is a fundamental approach to understand the processes of speciation. However, such traits are often affected by covariance structures that complicate the comprehension of these processes, especially because the interactive relationships between traits of different nature (e.g. morphology, behaviour, life-history) remain largely unknown in this context. In a common garden setup, we conducted an extensive examination of a large suit of traits putatively involved in the divergence of two morphs of Arctic charr (Salvelinus alpinus), and investigated the consequences of potential patterns of trait covariance on the phenotype of their hybrids. These traits were measured along ontogeny and involved growth, yolk sac resorption, developmental timing (hatching and the onset of exogeneous feeding), head morphology and feeding behaviour. Results: Growth trajectories provided the strongest signal of phenotypic divergence between the two charr. Strikingly, the first-generation hybrids did not show intermediate nor delayed growth but were similar to the smallest morph, suggesting parental biases in the inheritance of growth patterns. However, we did not observe extensive multivariate trait differences between the two morphs and their hybrids. Growth was linked to head morphology (suggesting that morphological variations in early juveniles relate to simple allometric effects) but this was the only strong signal of covariance observed between all the measured traits. Furthermore, we did not report evidence for differences in overall phenotypic variance between morphs, nor for enhanced phenotypic variability in their hybrids. Conclusion: Our study shed light on the multivariate aspect of development in a context of adaptive divergence. The lack of evidence for the integration of most traits into a single covariance structure suggested that phenotypic constraints may not always favour nor impede divergence toward ecological niches differing in numerous physical and ecological variables, as observed in the respective habitats of the two charr. Likewise, the role of hybridization as a disruptive agent of trait covariance may not necessarily be significant in the evolution of populations undergoing resource polymorphism.Publisher PDFPeer reviewe
Isotopic distribution of fission fragments in collisions between 238U beam and 9Be and 12C targets at 24 MeV/u
Inverse kinematics coupled to a high-resolution spectrometer is used to
investigate the isotopic yields of fission fragments produced in reactions
between a 238U beam at 24 MeV/u and 9Be and 12C targets. Mass, atomic number
and isotopic distributions are reported for the two reactions. These
informations give access to the neutron excess and the isotopic distribution
widths, which together with the atomic-number and mass distributions are used
to investigate the fusion-fission dynamics.Comment: Submitted to PR
Dynamics and Instabilities of Planar Tensile Cracks in Heterogeneous Media
The dynamics of tensile crack fronts restricted to advance in a plane are
studied. In an ideal linear elastic medium, a propagating mode along the crack
front with a velocity slightly less than the Rayleigh wave velocity, is found
to exist. But the dependence of the effective fracture toughness on
the crack velocity is shown to destabilize the crack front if
. Short wavelength radiation due to weak random
heterogeneities leads to this instability at low velocities. The implications
of these results for the crack dynamics are discussed.Comment: 12 page
Crack Front Waves and the dynamics of a rapidly moving crack
Crack front waves are localized waves that propagate along the leading edge
of a crack. They are generated by the interaction of a crack with a localized
material inhomogeneity. We show that front waves are nonlinear entities that
transport energy, generate surface structure and lead to localized velocity
fluctuations. Their existence locally imparts inertia, which is not
incorporated in current theories of fracture, to initially "massless" cracks.
This, coupled to crack instabilities, yields both inhomogeneity and scaling
behavior within fracture surface structure.Comment: Embedded Latex file including 4 figure
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