290 research outputs found
Development and external validation study of a melanoma risk prediction model incorporating clinically assessed naevi and solar lentigines
Background:
Melanoma risk prediction models could be useful for matching preventive interventions to patientsâ risk.
Objectives:
To develop and validate a model for incident firstâprimary cutaneous melanoma using clinically assessed risk factors.
Methods:
We used unconditional logistic regression with backward selection from the Australian Melanoma Family Study (461 cases and 329 controls) in which age, sex and city of recruitment were kept in each step, and we externally validated it using the Leeds Melanoma CaseâControl Study (960 cases and 513 controls). Candidate predictors included clinically assessed wholeâbody naevi and solar lentigines, and selfâassessed pigmentation phenotype, sun exposure, family history and history of keratinocyte cancer. We evaluated the predictive strength and discrimination of the model risk factors using odds per ageâ and sexâadjusted SD (OPERA) and the area under curve (AUC), and calibration using the HosmerâLemeshow test.
Results:
The final model included the number of naevi â„ 2 mm in diameter on the whole body, solar lentigines on the upper back (a sixâlevel scale), hair colour at age 18 years and personal history of keratinocyte cancer. Naevi was the strongest risk factor; the OPERA was 3·51 [95% confidence interval (CI) 2·71â4·54] in the Australian study and 2·56 (95% CI 2·23â2·95) in the Leeds study. The AUC was 0·79 (95% CI 0·76â0·83) in the Australian study and 0·73 (95% CI 0·70â0·75) in the Leeds study. The HosmerâLemeshow test Pâvalue was 0·30 in the Australian study and < 0·001 in the Leeds study.
Conclusions:
This model had good discrimination and could be used by clinicians to stratify patients by melanoma risk for the targeting of preventive interventions.
What's already known about this topic?
Melanoma risk prediction models may be useful in prevention by tailoring interventions to personalized risk levels.
For reasons of feasibility, time and cost many melanoma prediction models use selfâassessed risk factors. However, individuals tend to underestimate their naevus numbers.
What does this study add?
We present a melanoma risk prediction model, which includes clinicallyâassessed wholeâbody naevi and solar lentigines, and selfâassessed risk factors including pigmentation phenotype and history of keratinocyte cancer.
This model performs well on discrimination, the model's ability to distinguish between individuals with and without melanoma, and may assist clinicians to stratify patients by melanoma risk for targeted preventive interventions
Imprinting, honeymooning, or maturing: Testing three theories of how interfirm social bonding impacts suppliersâ allocations of resources to business customers
In business markets, does strength of social bonds that a supplier perceives with a specific customer influence the supplierâs allocations of resources relative to other customers? If social bonding does uniquely impact supplier allocation of resources to customers, does the impact vary by relationship duration? Relationship marketing and Homansâ framework for social behavior are the theoretical bases for the study, which uses survey data to examine three alternative models that indicate how suppliersâ perceptions of social bonds with customers influence the suppliersâ allocations of resources over time. Analysis of data from sales and marketing managers confirms that two of these models, the imprinting theory and the maturity theory, are relevant. The findings indicate that relationship managers need to take into account the clear effect that creation of strong social bonds in buyerâseller relationships, as distinct from financial bonds, has on the way in which suppliers allocate resources to those relationships and how relationship duration affects the way in which they do so. The study strengthens the argument, on a strong theoretical base, to adopt a collaborative, as opposed to a transactional, approach to buyerâseller relationships
Backward pion-nucleon scattering
A global analysis of the world data on differential cross sections and
polarization asymmetries of backward pion-nucleon scattering for invariant
collision energies above 3 GeV is performed in a Regge model. Including the
, , and trajectories, we
reproduce both angular distributions and polarization data for small values of
the Mandelstam variable , in contrast to previous analyses. The model
amplitude is used to obtain evidence for baryon resonances with mass below 3
GeV. Our analysis suggests a resonance with a mass of 2.83 GeV as
member of the trajectory from the corresponding Chew-Frautschi
plot.Comment: 12 pages, 16 figure
Classification of a supersolid: Trial wavefunctions, Symmetry breakings and Excitation spectra
A state of matter is characterized by its symmetry breaking and elementary
excitations.
A supersolid is a state which breaks both translational symmetry and internal
symmetry.
Here, we review some past and recent works in phenomenological
Ginsburg-Landau theories, ground state trial wavefunctions and microscopic
numerical calculations. We also write down a new effective supersolid
Hamiltonian on a lattice.
The eigenstates of the Hamiltonian contains both the ground state
wavefunction and all the excited states (supersolidon) wavefunctions. We
contrast various kinds of supersolids in both continuous systems and on
lattices, both condensed matter and cold atom systems. We provide additional
new insights in studying their order parameters, symmetry breaking patterns,
the excitation spectra and detection methods.Comment: REVTEX4, 19 pages, 3 figure
Transverse Beam Spin Asymmetries in Forward-Angle Elastic Electron-Proton Scattering
We have measured the beam-normal single-spin asymmetry in elastic scattering
of transversely-polarized 3 GeV electrons from unpolarized protons at Q^2 =
0.15, 0.25 (GeV/c)^2. The results are inconsistent with calculations solely
using the elastic nucleon intermediate state, and generally agree with
calculations with significant inelastic hadronic intermediate state
contributions. A_n provides a direct probe of the imaginary component of the
2-gamma exchange amplitude, the complete description of which is important in
the interpretation of data from precision electron-scattering experiments.Comment: 5 pages, 3 figures, submitted to Physical Review Letters; shortened
to meet PRL length limit, clarified some text after referee's comment
Strange Quark Contributions to Parity-Violating Asymmetries in the Forward G0 Electron-Proton Scattering Experiment
We have measured parity-violating asymmetries in elastic electron-proton
scattering over the range of momentum transfers 0.12 < Q^2 < 1.0 GeV^2. These
asymmetries, arising from interference of the electromagnetic and neutral weak
interactions, are sensitive to strange quark contributions to the currents of
the proton. The measurements were made at JLab using a toroidal spectrometer to
detect the recoiling protons from a liquid hydrogen target. The results
indicate non-zero, Q^2 dependent, strange quark contributions and provide new
information beyond that obtained in previous experiments.Comment: 5 pages, 2 figure
The G0 Experiment: Apparatus for Parity-Violating Electron Scattering Measurements at Forward and Backward Angles
In the G0 experiment, performed at Jefferson Lab, the parity-violating
elastic scattering of electrons from protons and quasi-elastic scattering from
deuterons is measured in order to determine the neutral weak currents of the
nucleon. Asymmetries as small as 1 part per million in the scattering of a
polarized electron beam are determined using a dedicated apparatus. It consists
of specialized beam-monitoring and control systems, a cryogenic hydrogen (or
deuterium) target, and a superconducting, toroidal magnetic spectrometer
equipped with plastic scintillation and aerogel Cerenkov detectors, as well as
fast readout electronics for the measurement of individual events. The overall
design and performance of this experimental system is discussed.Comment: Submitted to Nuclear Instruments and Method
Transmembrane inhibitor of RICTOR/mTORC2 in hematopoietic progenitors
Central to cellular proliferative, survival, and metabolic responses is the serine/threonine kinase mTOR, which is activated in many human cancers. mTOR is present in distinct complexes that are either modulated by AKT (mTORC1) or are upstream and regulatory of it (mTORC2). Governance of mTORC2 activity is poorly understood. Here, we report a transmembrane molecule in hematopoietic progenitor cells that physically interacts with and inhibits RICTOR, an essential component of mTORC2. Upstream of mTORC2 (UT2) negatively regulates mTORC2 enzymatic activity, reducing AKTS473, PKCa, and NDRG1 phosphorylation and increasing FOXO transcriptional activity in an mTORC2-dependent manner. Modulating UT2 levels altered animal survival in a T cell acute lymphoid leukemia (T-ALL) model that is known to be mTORC2 sensitive. These studies identify an inhibitory component upstream of mTORC2 in hematopoietic cells that can reduce mortality from NOTCH-induced T-ALL. A transmembrane inhibitor of mTORC2 may provide an attractive target to affect this critical cell regulatory pathway
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