37 research outputs found
Analytical solution of the Gross-Neveu model at finite density
Recent numerical calculations have shown that the ground state of the
Gross-Neveu model at finite density is a crystal. Guided by these results, we
can now present the analytical solution to this problem in terms of elliptic
functions. The scalar potential is the superpotential of the non-relativistic
Lame Hamiltonian. This model can also serve as analytically solvable toy model
for a relativistic superconductor in the Larkin-Ovchinnikov-Fulde-Ferrell
phase.Comment: 5 pages, no figures, revtex; vs2: appendix with analytical proof of
self-consistency adde
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
Management of early melanoma recurrence despite adjuvant anti-PD-1 antibody therapy
Background: Anti-programmed cell death protein 1 (PD-1) antibodies (PD1) prolong recurrence-free survival in high-risk resected melanoma; however, approximately 25%-30% of patients recur within 1 year. This study describes the pattern of recurrence, management and outcomes of patients who recur with adjuvant PD1 therapy.Patients and methods: Consecutive patients from 16 centres who recurred having received adjuvant PD1 therapy for resected stage III/IV melanoma were studied. Recurrence characteristics, management and outcomes were examined; patients with mucosal melanoma were analysed separately.Results: Melanoma recurrence occurred in 147 (17%) of ∼850 patients treated with adjuvant PD1. In those with cutaneous melanoma (n = 136), median time to recurrence was 4.6 months (range 0.3-35.7); 104 (76%) recurred during (ON) adjuvant PD1 after a median 3.2 months and 32 (24%) following (OFF) treatment cessation after a median 12.5 months, including in 21 (15%) who ceased early for toxicity. Fifty-nine (43%) recurred with locoregional disease only and 77 (57%) with distant disease. Of those who recurred locally, 22/59 (37%) subsequently recurred distantly. Eighty-nine (65%) patients received systemic therapy after recurrence. Of those who recurred ON adjuvant PD1, none (0/6) responded to PD1 alone; 8/33 assessable patients (24%) responded to ipilimumab (alone or in combination with PD1) and 18/23 (78%) responded to BRAF/MEK inhibitors. Of those who recurred OFF adjuvant PD1, two out of five (40%) responded to PD1 monotherapy, two out of five (40%) responded to ipilimumab-based therapy and 9/10 (90%) responded to BRAF/MEK inhibitors.Conclusions: Most patients who recur early despite adjuvant PD1 develop distant metastases. In those who recur ON adjuvant PD1, there is minimal activity of further PD1 monotherapy, but ipilimumab (alone or in combination with PD1) and BRAF/MEK inhibitors have clinical utility. Retreatment with PD1 may have activity in select patients who recur OFF PD1.</p
Combined BRAF and MEK inhibition versus BRAF inhibition alone in melanoma
Results The median progression-free survival was 9.3 months in the dabrafenib-trametinib group and 8.8 months in the dabrafenib-only group (hazard ratio for progression or death in the dabrafenib-trametinib group, 0.75; 95% confidence interval [CI], 0.57 to 0.99; P = 0.03). The overall response rate was 67% in the dabrafenib-trametinib group and 51% in the dabrafenib-only group (P = 0.002). At 6 months, the interim overall survival rate was 93% with dabrafenib-trametinib and 85% with dabrafenib alone (hazard ratio for death, 0.63; 95% CI, 0.42 to 0.94; P = 0.02). However, a specified efficacy-stopping boundary (two-sided P = 0.00028) was not crossed. Rates of adverse events were similar in the two groups, although more dose modifications occurred in the dabrafenib-trametinib group. The rate of cutaneous squamous-cell carcinoma was lower in the dabrafenib-trametinib group than in the dabrafenib-only group (2% vs. 9%), whereas pyrexia occurred in more patients (51% vs. 28%) and was more often severe (grade 3, 6% vs. 2%) in the dabrafenib- trametinib group. Conclusions A combination of dabrafenib and trametinib, as compared with dabrafenib alone, improved the rate of progression-free survival in previously untreated patients who had metastatic melanoma with BRAF V600E or V600K mutations.Background Combined BRAF and MEK inhibition, as compared with BRAF inhibition alone, delays the emergence of resistance and reduces toxic effects in patients who have melanoma with BRAF V600E or V600K mutations.Methods In this phase 3 trial, we randomly assigned 423 previously untreated patients who had unresectable stage IIIC or stage IV melanoma with a BRAF V600E or V600K mutation to receive a combination of dabrafenib (150 mg orally twice daily) and trametinib (2 mg orally once daily) or dabrafenib and placebo. The primary end point was progression-free survival. Secondary end points included overall survival, response rate, response duration, and safety. A preplanned interim overall survival analysis was conducted
Scintillation light in SBND: simulation, reconstruction, and expected performance of the photon detection system
SBND is the near detector of the Short-Baseline Neutrino program at Fermilab. Its location near to the Booster Neutrino Beam source and relatively large mass will allow the study of neutrino interactions on argon with unprecedented statistics. This paper describes the expected performance of the SBND photon detection system, using a simulated sample of beam neutrinos and cosmogenic particles. Its design is a dual readout concept combining a system of 120 photomultiplier tubes, used for triggering, with a system of 192 X-ARAPUCA devices, located behind the anode wire planes. Furthermore, covering the cathode plane with highly-reflective panels coated with a wavelength-shifting compound recovers part of the light emitted towards the cathode, where no optical detectors exist. We show how this new design provides a high light yield and a more uniform detection efficiency, an excellent timing resolution and an independent 3D-position reconstruction using only the scintillation light. Finally, the whole reconstruction chain is applied to recover the temporal structure of the beam spill, which is resolved with a resolution on the order of nanoseconds
Survival of patients with advanced metastatic melanoma: the impact of novel therapies–update 2017
The treatment of metastatic melanoma is still undergoing a process of major change. The two most important novel therapeutic strategies, selective kinase inhibitors and immune checkpoint blockers, both significantly prolong survival times of patients with advanced metastatic disease. Different agents, dose regimens and combinations have been tested against each other vigorously within these two groups. However, results from prospective head-to-head comparative studies of both strategies are still lacking. We performed an exploratory analysis of survival data from selected clinical trials representative for the new treatment strategies in advanced metastatic melanoma. Eighty-three Kaplan-Meier survival curves from 25 trials were digitised and grouped by therapeutic strategy and treatment line. For each of these groups, mean survival curves were generated for progression-free (PFS) and overall survival (OS) by weighted averaging. Survival curves grouped together by therapeutic strategy revealed a high concordance, particularly in the first-line setting. For kinase inhibitors, the most favourable PFS and OS in all therapy lines were observed for combined BRAF plus MEK inhibition. For immune checkpoint inhibitors, combined PD-1 plus CTLA-4 inhibition demonstrated the best survival outcome in all categories except for OS in first-line therapy. For the latter, combined PD-1 plus CTLA-4 inhibition showed similar outcomes as single-agent PD-1 inhibition. Comparison of kinase inhibitors and checkpoint blockers revealed a superiority of combined BRAF plus MEK inhibition within the first 6 months, later changing to a superiority of PD-1 blockers alone or in combination with CTLA-4 blockers. These results need confirmation by prospective clinical trials
Dynamic professional boundaries in the healthcare workforce
The healthcare professions have never been static in terms of their
own disciplinary boundaries, nor in their role or status in society.
Healthcare provision has been defined by changing societal
expectations and beliefs, new ways of perceiving health and illness,
the introduction of a range of technologies and, more recently, the
formal recognition of particular groups through the introduction
of education and regulation. It has also been shaped by both interprofessional
and profession-state relationships forged over time.
A number of factors have converged that place new pressures on
workforce boundaries, including an unmet demand for some
healthcare services; neo-liberal management philosophies and a
greater emphasis on consumer preferences than professional-led
services. To date, however, there has been little analysis of the
evolution of the workforce as a whole. The discussion of workforce
change that has taken place has largely been from the perspective
of individual disciplines. Yet the dynamic boundaries of each
discipline mean that there is an interrelationship between the
components of the workforce that cannot be ignored. The purpose
of this paper is to describe four directions in which the existing
workforce can change: diversification; specialisation and vertical
and horizontal substitution, and to discuss the implications of
these changes for the workforce