2,160 research outputs found
Vacuum Stability, Perturbativity, and Scalar Singlet Dark Matter
We analyze the one-loop vacuum stability and perturbativity bounds on a
singlet extension of the Standard Model (SM) scalar sector containing a scalar
dark matter candidate. We show that the presence of the singlet-doublet quartic
interaction relaxes the vacuum stability lower bound on the SM Higgs mass as a
function of the cutoff and lowers the corresponding upper bound based on
perturbativity considerations. We also find that vacuum stability requirements
may place a lower bound on the singlet dark matter mass for given singlet
quartic self coupling, leading to restrictions on the parameter space
consistent with the observed relic density. We argue that discovery of a light
singlet scalar dark matter particle could provide indirect information on the
singlet quartic self-coupling.Comment: 25 pages, 10 figures; v2 - fixed minor typos; v3 - added to text
discussions of other references, changed coloring of figures for easier black
and white viewin
Phenomenological Consequences of sub-leading Terms in See-Saw Formulas
Several aspects of next-to-leading (NLO) order corrections to see-saw
formulas are discussed and phenomenologically relevant situations are
identified. We generalize the formalism to calculate the NLO terms developed
for the type I see-saw to variants like the inverse, double or linear see-saw,
i.e., to cases in which more than two mass scales are present. In the standard
type I case with very heavy fermion singlets the sub-leading terms are
negligible. However, effects in the percent regime are possible when
sub-matrices of the complete neutral fermion mass matrix obey a moderate
hierarchy, e.g. weak scale and TeV scale. Examples are cancellations of large
terms leading to small neutrino masses, or inverse see-saw scenarios. We
furthermore identify situations in which no NLO corrections to certain
observables arise, namely for mu-tau symmetry and cases with a vanishing
neutrino mass. Finally, we emphasize that the unavoidable unitarity violation
in see-saw scenarios with extra fermions can be calculated with the formalism
in a straightforward manner.Comment: 22 pages, matches published versio
Publishing and sharing multi-dimensional image data with OMERO
Imaging data are used in the life and biomedical sciences to measure the molecular and structural composition and dynamics of cells, tissues, and organisms. Datasets range in size from megabytes to terabytes and usually contain a combination of binary pixel data and metadata that describe the acquisition process and any derived results. The OMERO image data management platform allows users to securely share image datasets according to specific permissions levels: data can be held privately, shared with a set of colleagues, or made available via a public URL. Users control access by assigning data to specific Groups with defined membership and access rights. OMERO’s Permission system supports simple data sharing in a lab, collaborative data analysis, and even teaching environments. OMERO software is open source and released by the OME Consortium at www.openmicroscopy.org
Suitability of PSA-detected localised prostate cancers for focal therapy: Experience from the ProtecT study
This article is available through a Creative Commons Attribution-NonCommercial-Share Alike 3.0 Unported License. Copyright @ 2011 Cancer Research UK.Background: Contemporary screening for prostate cancer frequently identifies small volume, low-grade lesions. Some clinicians have advocated focal prostatic ablation as an alternative to more aggressive interventions to manage these lesions. To identify which patients might benefit from focal ablative techniques, we analysed the surgical specimens of a large sample of population-detected men undergoing radical prostatectomy as part of a randomised clinical trial. Methods: Surgical specimens from 525 men who underwent prostatectomy within the ProtecT study were analysed to determine tumour volume, location and grade. These findings were compared with information available in the biopsy specimen to examine whether focal therapy could be provided appropriately. Results: Solitary cancers were found in prostatectomy specimens from 19% (100 out of 525) of men. In addition, 73 out of 425 (17%) men had multiple cancers with a solitary significant tumour focus. Thus, 173 out of 525 (33%) men had tumours potentially suitable for focal therapy. The majority of these were small, well-differentiated lesions that appeared to be pathologically insignificant (38–66%). Criteria used to select patients for focal prostatic ablation underestimated the cancer's significance in 26% (34 out of 130) of men and resulted in overtreatment in more than half. Only 18% (24 out of 130) of men presumed eligible for focal therapy, actually had significant solitary lesions. Conclusion: Focal therapy appears inappropriate for the majority of men presenting with prostate-specific antigen-detected localised prostate cancer. Unifocal prostate cancers suitable for focal ablation are difficult to identify pre-operatively using biopsy alone. Most lesions meeting criteria for focal ablation were either more aggressive than expected or posed little threat of progression.National Institute for Health Researc
Interferon-α resistance in renal carcinoma cells is associated with defective induction of signal transducer and activator of transcription 1 which can be restored by a supernatant of phorbol 12-myristate 13-acetate stimulated peripheral blood mononuclear cells
Therapy of selected human malignancies with interferon-α is widely accepted but often complicated by the emergence of interferon-α resistance. Interferon is a pleiotropic cytokine with antiproliferative, antitumour, antiviral and immunmodulatory effect; it signals through the Jak-STAT signal transduction pathway where signal transducer and activator of transcription 1 plays an important role. Here we report both, a lack of signal transducer and activator of transcription induction in interferon-α resistant renal cell carcinoma cells and signal transducer and activator of transcription 1 reinduction of phorbol 12-myristate 13-acetate-stimulated peripheral blood mononuclear cells supernatant. Preliminary experiments on the identification of the molecules that reinducing signal transducers and activators of transcription 1 indicate that interferon-γ may be the responsible candidate cytokine, but several others may be involved as well. This work provides the basis for therapeutic strategies directed at the molecular modulation of interferon-α resistance in human neoplasms
Decoupling property of the supersymmetric Higgs sector with four doublets
In supersymmetric standard models with multi Higgs doublet fields,
selfcoupling constants in the Higgs potential come only from the D-terms at the
tree level. We investigate the decoupling property of additional two heavier
Higgs doublet fields in the supersymmetric standard model with four Higgs
doublets. In particular, we study how they can modify the predictions on the
quantities well predicted in the minimal supersymmetric standard model (MSSM),
when the extra doublet fields are rather heavy to be measured at collider
experiments. The B-term mixing between these extra heavy Higgs bosons and the
relatively light MSSM-like Higgs bosons can significantly change the
predictions in the MSSM such as on the masses of MSSM-like Higgs bosons as well
as the mixing angle for the two light CP-even scalar states. We first give
formulae for deviations in the observables of the MSSM in the decoupling region
for the extra two doublet fields. We then examine possible deviations in the
Higgs sector numerically, and discuss their phenomenological implications.Comment: 26 pages, 24 figures, text sligtly modified,version to appear in
Journal of High Energy Physic
Unilateral cross bite treated by corticotomy-assisted expansion: two case reports
<p>Abstract</p> <p>Background</p> <p>True unilateral posterior crossbite in adults is a challenging malocclusion to treat. Conventional expansion methods are expected to have some shortcomings. The aim of this paper is to introduce a new technique for treating unilateral posterior crossbite in adults, namely, corticotomy-assisted expansion (CAE) applied on two adult patients: one with a true unilateral crossbite and the other with an asymmetrical bilateral crossbite, both treated via modified corticotomy techniques and fixed orthodontic appliances.</p> <p>Methods</p> <p>Two cases with asymmetric maxillary constriction were treated using CAE.</p> <p>Results</p> <p>In both cases, effective asymmetrical expansion was achieved using CAE, and functional occlusion was established as well.</p> <p>Conclusions</p> <p>Unilateral CAE presents an effective and reliable technique to treat true unilateral crossbite.</p
Decoupling of Massive Right-handed Neutrinos
We investigate the effect of B+L - violating anomalous generation of massive
right-handed neutrinos on their decoupling, when the right-handed neutrino mass
is considerably greater than the right-handed gauge boson masses. Considering
normal annihilation channels, the Lee-Weinberg type of calculation, in this
case, gives an upper bound of about 700 Gev, which casts doubt on the existence
of such a right-handed neutrino mass greater than right-handed gauge boson
masses. We examine the possibility that a consideration of anomalous effects
related to the SU(2)_R gauge group may turn this into a lower bound of the
order of 100 Tev.Comment: 28 Pages, Latex, 2 figure
The Interplay Between GUT and Flavour Symmetries in a Pati-Salam x S4 Model
Both Grand Unified symmetries and discrete flavour symmetries are appealing
ways to describe apparent structures in the gauge and flavour sectors of the
Standard Model. Both symmetries put constraints on the high energy behaviour of
the theory. This can give rise to unexpected interplay when building models
that possess both symmetries. We investigate on the possibility to combine a
Pati-Salam model with the discrete flavour symmetry that gives rise to
quark-lepton complementarity. Under appropriate assumptions at the GUT scale,
the model reproduces fermion masses and mixings both in the quark and in the
lepton sectors. We show that in particular the Higgs sector and the running
Yukawa couplings are strongly affected by the combined constraints of the Grand
Unified and family symmetries. This in turn reduces the phenomenologically
viable parameter space, with high energy mass scales confined to a small region
and some parameters in the neutrino sector slightly unnatural. In the allowed
regions, we can reproduce the quark masses and the CKM matrix. In the lepton
sector, we reproduce the charged lepton masses, including bottom-tau
unification and the Georgi-Jarlskog relation as well as the two known angles of
the PMNS matrix. The neutrino mass spectrum can present a normal or an inverse
hierarchy, and only allowing the neutrino parameters to spread into a range of
values between and , with .
Finally, our model suggests that the reactor mixing angle is close to its
current experimental bound.Comment: 62 pages, 4 figures; references added, version accepted for
publication in JHE
“Excellence R Us”: university research and the fetishisation of excellence
The rhetoric of “excellence” is pervasive across the academy. It is used to refer to research outputs as well as researchers, theory and education, individuals and organisations, from art history to zoology. But does “excellence” actually mean anything? Does this pervasive narrative of “excellence” do any good? Drawing on a range of sources we interrogate “excellence” as a concept and find that it has no intrinsic meaning in academia. Rather it functions as a linguistic interchange mechanism. To investigate whether this linguistic function is useful we examine how the rhetoric of excellence combines with narratives of scarcity and competition to show that the hypercompetition that arises from the performance of “excellence” is completely at odds with the qualities of good research. We trace the roots of issues in reproducibility, fraud, and homophily to this rhetoric. But we also show that this rhetoric is an internal, and not primarily an external, imposition. We conclude by proposing an alternative rhetoric based on soundness and capacity-building. In the final analysis, it turns out that that “excellence” is not excellent. Used in its current unqualified form it is a pernicious and dangerous rhetoric that undermines the very foundations of good research and scholarship
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