3,445 research outputs found
Testing Radiative Neutrino Mass Models at the LHC
The Large Hadron Collider provides us new opportunities to search for the
origin of neutrino mass. Beyond the minimal see-saw models a plethora of models
exist which realise neutrino mass at tree- or loop-level, and it is important
to be sure that these possibilities are satisfactorily covered by searches. The
purpose of this paper is to advance a systematic approach to this problem.
Majorana neutrino mass models can be organised by SM-gauge-invariant operators
which violate lepton number by two units. In this paper we write down the
minimal ultraviolet completions for all of the mass-dimension 7 operators. We
predict vector-like quarks, vector-like leptons, scalar leptoquarks, a charged
scalar, and a scalar doublet, whose properties are constrained by neutrino
oscillation data. A detailed collider study is presented for
and completions with a
vector-like quark and a leptoquark
. The existing LHC limits extracted from
searches for vector-like fermions and sbottoms/stops are
GeV and GeV.Comment: 40 pages, 13 figures; references added, minor changes, matches JHEP
versio
A decreased probability of habitable planet formation around low-mass stars
Smaller terrestrial planets (< 0.3 Earth masses) are less likely to retain
the substantial atmospheres and ongoing tectonic activity probably required to
support life. A key element in determining if sufficiently massive "sustainably
habitable" planets can form is the availability of solid planet-forming
material. We use dynamical simulations of terrestrial planet formation from
planetary embryos and simple scaling arguments to explore the implications of
correlations between terrestrial planet mass, disk mass, and the mass of the
parent star. We assume that the protoplanetary disk mass scales with stellar
mass as Mdisk ~ f Mstar^h, where f measures the relative disk mass, and 1/2 < h
< 2, so that disk mass decreases with decreasing stellar mass. We consider
systems without Jovian planets, based on current models and observations for M
stars. We assume the mass of a planet formed in some annulus of a disk with
given parameters is proportional to the disk mass in that annulus, and show
with a suite of simulations of late-stage accretion that the adopted
prescription is surprisingly accurate. Our results suggest that the fraction of
systems with sufficient disk mass to form > 0.3 Earth mass habitable planets
decreases for low-mass stars for every realistic combination of parameters.
This "habitable fraction" is small for stellar masses below a mass in the
interval 0.5 to 0.8 Solar masses, depending on disk parameters, an interval
that excludes most M stars. Radial mixing and therefore water delivery are
inefficient in lower-mass disks commonly found around low-mass stars, such that
terrestrial planets in the habitable zones of most low-mass stars are likely to
be small and dry.Comment: Accepted to ApJ. 11 pages, 6 figure
The Effects of Feeding on Hematological and Plasma Biochemical Profiles in Green (Chelonia mydas) and Kemp's Ridley (Lepidochelys kempii) Sea Turtles
In mammals, lipemic blood from sampling too soon after an animal feeds can have substantial effects on biochemical values. Plasma biochemical values in reptiles may be affected by species, age, season, and nutritional state. However, fasting status is not routinely considered when sampling reptile blood. In this paper, we evaluated 2-hour postprandial blood collection in two sea turtle species to investigate the effects of feeding on hematological and plasma biochemical values. Feeding had no significant effects on hematological values in either species, nor did it have an effect on plasma biochemistry values in Kemp's ridley sea turtles. In postprandial green turtles, total protein, albumin, ALP, AST, ALT, amylase, and cholesterol increased significantly, and chloride decreased significantly. Although statistically significant changes were observed, the median percent differences between pre- and postprandial values did not exceed 10% for any of these analytes and would not likely alter the clinical interpretation
New Genomic Structure for Prostate Cancer Specific Gene PCA3 within BMCC1: Implications for Prostate Cancer Detection and Progression
The prostate cancer antigen 3 (PCA3/DD3) gene is a highly specific biomarker upregulated in prostate cancer (PCa). In order to understand the importance of PCA3 in PCa we investigated the organization and evolution of the PCA3 gene locus. METHODS/PRINCIPAL FINDINGS: We have employed cDNA synthesis, RTPCR and DNA sequencing to identify 4 new transcription start sites, 4 polyadenylation sites and 2 new differentially spliced exons in an extended form of PCA3. Primers designed from these novel PCA3 exons greatly improve RT-PCR based discrimination between PCa, PCa metastases and BPH specimens. Comparative genomic analyses demonstrated that PCA3 has only recently evolved in an anti-sense orientation within a second gene, BMCC1/PRUNE2. BMCC1 has been shown previously to interact with RhoA and RhoC, determinants of cellular transformation and metastasis, respectively. Using RT-PCR we demonstrated that the longer BMCC1-1 isoform - like PCA3 - is upregulated in PCa tissues and metastases and in PCa cell lines. Furthermore PCA3 and BMCC1-1 levels are responsive to dihydrotestosterone treatment. CONCLUSIONS/SIGNIFICANCE: Upregulation of two new PCA3 isoforms in PCa tissues improves discrimination between PCa and BPH. The functional relevance of this specificity is now of particular interest given PCA3's overlapping association with a second gene BMCC1, a regulator of Rho signalling. Upregulation of PCA3 and BMCC1 in PCa has potential for improved diagnosis
âNot a big dealâ? exploring the accounts of adult children of lesbian, gay and trans parents
© 2016 Taylor & Francis. Most literature on lesbian, gay, bisexual and trans families has focused on the psychological and social well-being of school aged children with lesbian, gay and trans (LGT) parents. The aim of the present study was to explore how the adult children of LGT parents make sense of their families. The study focused both on recollections of childhood and on current feelings and experiences. Thirteen women and 1 man completed either an email interview or an online qualitative survey; the data were analysed using thematic analysis. The participantsâ accounts were protective of their parents and often drew on the normalizing discourses evident in pro-gay rhetoric about LGT parenting to minimize the significance of their parentsâ sexuality/gender identity and the âtaint of differenceâ associated with LGT families. At the same time, the participants strongly challenged heterosexist and homophobic/transphobic assumptions about LGT families and viewed the source of any difficulties they and their parents experienced as resulting from a hetero/cisnormative social context that prevented LGT people and their families from living openly and authentically without fear of discrimination. The results highlight the continuing micro impacts of hetero/cisnormativity in the lives of LGT people and their families
Chemical fingerprints encode mother-offspring similarity, colony membership, relatedness and genetic quality in fur seals
Chemical communication underpins virtually all aspects of vertebrate social life, yet remains poorly understood because of its highly complex mechanistic basis. We therefore used chemical fingerprinting of skin swabs and genetic analysis to explore the chemical cues that may underlie motherâoffspring recognition in colonially breeding Antarctic fur seals. By sampling motherâoffspring pairs from two different colonies, using a variety of statistical approaches and genotyping a large panel of microsatellite loci, we show that colony membership, motherâoffspring similarity, heterozygosity, and genetic relatedness are all chemically encoded. Moreover, chemical similarity between mothers and offspring reflects a combination of genetic and environmental influences, the former partly encoded by substances resembling known pheromones. Our findings reveal the diversity of information contained within chemical fingerprints and have implications for understanding motherâoffspring communication, kin recognition, and mate choice
Short-term variability in Greenland Ice Sheet motion forced by time-varying meltwater inputs: implications for the relationship between subglacial drainage system behavior and ice velocity.
High resolution measurements of ice motion along a -120 km transect in a land-terminating section of the GrIS reveal short-term velocity variations (<1 day), which are forced by rapid variations in meltwater input to the subglacial drainage system from the ice sheet surface. The seasonal changes in ice velocity at low elevations (<1000 m) are dominated by events lasting from 1 day to 1 week, although daily cycles are largely absent at higher elevations, reflecting different patterns of meltwater input. Using a simple model of subglacial conduit behavior we show that the seasonal record of ice velocity can be understood in terms of a time-varying water input to a channelized subglacial drainage system. Our investigation substantiates arguments that variability in the duration and rate, rather than absolute volume, of meltwater delivery to the subglacial drainage system are important controls on seasonal patterns of subglacial water pressure, and therefore ice velocity. We suggest that interpretations of hydro-dynamic behavior in land-terminating sections of the GrIS margin which rely on steady state drainage theories are unsuitable for making predictions about the effect of increased summer ablation on future rates of ice motion. © 2012. American Geophysical Union
The impact of exchanging the light and heavy chains on the structures of bovine ultralong antibodies
The third complementaryâdetermining regions of the heavyâchain (CDR3H) variable regions (VH) of some cattle antibodies are highly extended, consisting of 48 or more residues. These `ultralong' CDR3Hs form ÎČâribbon stalks that protrude from the surface of the antibody with a disulfide crossâlinked knob region at their apex that dominates antigen interactions over the other CDR loops. The structure of the Fab fragment of a naturally paired bovine ultralong antibody (D08), identified by single Bâcell sequencing, has been determined to 1.6 Ă
resolution. By swapping the D08 native light chain with that of an unrelated antigenâunknown ultralong antibody, it is shown that interactions between the CDR3s of the variable domains potentially affect the fine positioning of the ultralong CDR3H; however, comparison with other crystallographic structures shows that crystalline packing is also a major contributor. It is concluded that, on balance, the exact positioning of ultralong CDR3H loops is most likely to be due to the constraints of crystal packing
Thinking about Later Life: Insights from the Capability Approach
A major criticism of mainstream gerontological frameworks is the inability of such frameworks to appreciate and incorporate issues of diversity and difference in engaging with experiences of aging. Given the prevailing socially structured nature of inequalities, such differences matter greatly in shaping experiences, as well as social constructions, of aging. I argue that Amartya Senâs capability approach (2009) potentially offers gerontological scholars a broad conceptual framework that places at its core consideration of human beings (their values) and centrality of human diversity. As well as identifying these key features of the capability approach, I discuss and demonstrate their relevance to thinking about old age and aging. I maintain that in the context of complex and emerging identities in later life that shape and are shaped by shifting people-place and people-people relationships, Senâs capability approach offers significant possibilities for gerontological research
Simulations of Mixed Morphology Supernova Remnants With Anisotropic Thermal Conduction
We explore the role of anisotropic thermal conduction on the evolution of
supernova remnants through interstellar media with a range of densities via
numerical simulations. We find that a remnant expanding in a dense environment
can produce centre-bright hard x-ray emission within 20 kyr, and centre-bright
soft x-ray emission within 60 kyr of the supernova event. In a more tenuous
environment, the appearance of a centre-bright structure in hard x-rays is
delayed until about 60 kyr. The soft x-ray emission from such a remnant may not
become centre bright during its observable lifetime. This can explain the
observations that show that mixed-morphology supernova remnants preferentially
occur close to denser, molecular environments. Remnants expanding into denser
environments tend to be smaller, making it easier for thermal conduction to
make larger changes in the temperatures of their hot gas bubbles. We show that
the lower temperatures make it very favorable to use high-stage ions as
diagnostics of the hot gas bubbles in SNRs. In particular, the distribution of
O VIII transitions from shell-bright at early epochs to centre-bright at later
epochs in the evolution of an SNR expanding in a dense ISM when the physics of
thermal conduction is included.Comment: 8 pages, 5 figures, submitted to Monthly Notice
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