First Direct Detection Constraints on Planck-Scale Mass Dark Matter with Multiple-Scatter Signatures Using the DEAP-3600 Detector

Dark matter with Planck-scale mass (≃10^{19}  GeV/c^{2}) arises in well-motivated theories and could be produced by several cosmological mechanisms. A search for multiscatter signals from supermassive dark matter was performed with a blind analysis of data collected over a 813 d live time with DEAP-3600, a 3.3 t single-phase liquid argon-based detector at SNOLAB. No candidate signals were observed, leading to the first direct detection constraints on Planck-scale mass dark matter. Leading limits constrain dark matter masses between 8.3×10^{6} and 1.2×10^{19}  GeV/c^{2}, and ^{40}Ar-scattering cross sections between 1.0×10^{-23} and 2.4×10^{-18}  cm^{2}. These results are interpreted as constraints on composite dark matter models with two different nucleon-to-nuclear cross section scalings.

Pulse-shape discrimination against low-energy Ar-39 beta decays in liquid argon with 4.5 tonne-years of DEAP-3600 data

The DEAP-3600 detector searches for the scintillation signal from dark matter particles scattering on a 3.3 tonne liquid argon target. The largest background comes from 39 Ar beta decays and is suppressed using pulse-shape discrimination (PSD). We use two types of PSD estimator: the prompt-fraction, which considers the fraction of the scintillation signal in a narrow and a wide time window around the event peak, and the log-likelihood-ratio, which compares the observed photon arrival times to a signal and a background model. We furthermore use two algorithms to determine the number of photons detected at a given time: (1) simply dividing the charge of each PMT pulse by the mean single-photoelectron charge, and (2) a likelihood analysis that considers the probability to detect a certain number of photons at a given time, based on a model for the scintillation pulse shape and for afterpulsing in the light detectors. The prompt-fraction performs approximately as well as the log-likelihood-ratio PSD algorithm if the photon detection times are not biased by detector effects. We explain this result using a model for the information carried by scintillation photons as a function of the time when they are detected.

First Results from the DEAP-3600 Dark Matter Search with Argon at SNOLAB

This Letter reports the first results of a direct dark matter search with the DEAP-3600 single-phase liquid argon (LAr) detector. The experiment was performed 2 km underground at SNOLAB (Sudbury, Canada) utilizing a large target mass, with the LAr target contained in a spherical acrylic vessel of 3600 kg capacity. The LAr is viewed by an array of PMTs, which would register scintillation light produced by rare nuclear recoil signals induced by dark matter particle scattering. An analysis of 4.44 live days (fiducial exposure of 9.87 ton day) of data taken during the initial filling phase demonstrates the best electronic recoil rejection using pulse-shape discrimination in argon, with leakage <1.2×10^{-7} (90% C.L.) between 15 and 31  keV_{ee}. No candidate signal events are observed, which results in the leading limit on weakly interacting massive particle (WIMP)-nucleon spin-independent cross section on argon, <1.2×10^{-44}  cm^{2} for a 100  GeV/c^{2} WIMP mass (90% C.L.).

No difference in effectiveness between focused and radial shockwave therapy for treating patellar tendinopathy: a randomized controlled trial

PURPOSE

The aim of the study was to compare the effectiveness of focused shockwave therapy (FSWT) and radial shockwave therapy (RSWT) for treating patellar tendinopathy.

METHODS

Patients were randomized into two groups. One group received three sessions of FSWT, and the other group received three sessions of RSWT. Both groups also received an eccentric training programme. Follow-up measurements took place 1, 4, 7 and 14 weeks after the final shockwave treatment. The primary outcome measure was the Victorian Institute of Sport Assessment-Patella (VISA-P) questionnaire. Secondary outcome measures were pain during ADL, sports activities and the decline squat.

RESULTS

Forty-three subjects (57 tendons) were included in the study. Twenty-one subjects (31 tendons) received FSWT, and 22 subjects (26 tendons) received RSWT. Both groups improved significantly on the VISA-P score, but there were no differences in improvement between the FSWT group (15 points on the VISA-P) and the RSWT group (9.6 points, n.s.). This was also the case for the secondary outcome measures.

CONCLUSION

There were no statistically significant differences in effectiveness between FSWT and RSWT. It is therefore not possible to recommend one treatment over the other on grounds of outcome. Both groups improved significantly, although it is questionable whether this difference is clinically relevant.

LEVEL OF EVIDENCE

II.

Transfer of information on palliative home care during the out-of-hours period

BACKGROUND

Continuity of end-of-life care for patients receiving palliative care is an important challenge for out-of-hours services in general practice.

AIM

To investigate how frequent information is transferred on patients receiving palliative care from GPs to the out-of-hours services, to explore the perceptions of GP's on this information transfer and to study the relation between information transfer and the used GP information systems.

METHODS

This is a mixed-method design study. The frequency of information transfer to the out-of-hours services was investigated by analyzing a regional out-of-hours database. Barriers and promoting factors for this transfer of information were investigated by using semi-structured interviews among a purposive sample of GPs from the same region. The relation between information transfer and the GP information system was investigated by a postal questionnaire in a national random selection of GPs.

RESULTS

When a palliative patient contacted the out-of-hours service, for 20% of these patients, a transfer of information was available and only half of these transfers included an anticipating end-of-life plan. All interviewed GPs considered continuity of care for these patients as important. However, some doubted whether a transfer of information is relevant for the quality of care. There was no relation between the information transfer and the used GP information systems.

CONCLUSION

For only a minority of patients receiving palliative care, a transfer of information including an anticipating management plan was present. There is a large variation in the opinions of GPs on how to organize continuity of end-of-life care.

Clinical evaluation of lymphocyte sub-populations and oxygen radical production in sarcoidosis and idiopathic pulmonary fibrosis

The purpose of this study was to investigate the relationship between bronchoalveolar lavage (BAL)-derived parameters of interstitial lung disease and clinical and lung function parameters in 34 patients with sarcoidosis and 23 patients with idiopathic pulmonary fibrosis (IPF). BAL findings of healthy individuals served as controls. Cell content and differentiation of BAL fluid were determined. Oxygen radical (O2-) production of BAL cells and of blood polymorphonuclear (PMN) cells was measured. Phenotypes of lung and blood lymphocytes were determined by immunoperoxidase staining. In addition, lung function was assessed, chest X-rays were made and serum ACE was measured. Lymphocyte alveolitis in sarcoidosis was associated with increased alveolar macrophage (AM) O2- production (P < 0.025 vs. sarcoidosis with normal lymphocyte counts). Patients with extrapulmonary sarcoidosis had higher CD4/CD8 ratios in BAL (P < 0.025) and shorter disease duration (P < 0.01) than those with strictly pulmonary sarcoidosis. Disease duration in sarcoidosis correlated inversely with the number of BAL cells (r = -0.38, P < 0.05), the relative and absolute number of lymphocytes in BAL fluid (r = -0.34, P < 0.05 and r = -0.44, P < 0.01, respectively) and the percentage of CD4-positive cells and the CD4/CD8 ratio (r = -0.43, P < 0.05 and r = -0.48, P < 0.025, respectively). Although significant increases in O2- production by BAL cells were observed in both IPF and sarcoidosis, only in sarcoidosis was a higher AM O2- production associated with a significantly lower total lung capacity (r = -0.67, P < 0.005) and pulmonary diffusing capacity TLCO (r = -0.50, P < 0.05). In conclusion, our findings show that lung lymphocyte phenotypes differ among patients with pulmonary and extrapulmonary sarcoidosis and that O2- production is upregulated in active sarcoidosis. In addition, our findings suggest that different relationships between BAL data and lung function in patients with sarcoidosis and IPF may be explained by differences in disease duration. In IPF, disease duration is likely to be underestimated because of its insidious onset. In sarcoidosis, the presence of extrapulmonary symptoms, helpful to establish an early diagnosis, is associated with significant BAL lymphocytosis.