Quantum-Enhanced Advanced LIGO Detectors in the Era of Gravitational-Wave Astronomy

The Laser Interferometer Gravitational Wave Observatory (LIGO) has been directly detecting gravitational waves from compact binary mergers since 2015. We report on the first use of squeezed vacuum states in the direct measurement of gravitational waves with the Advanced LIGO H1 and L1 detectors. This achievement is the culmination of decades of research to implement squeezed states in gravitational-wave detectors. During the ongoing O3 observation run, squeezed states are improving the sensitivity of the LIGO interferometers to signals above 50 Hz by up to 3 dB, thereby increasing the expected detection rate by 40% (H1) and 50% (L1).

Search for Subsolar Mass Ultracompact Binaries in Advanced LIGO's Second Observing Run

We present a search for subsolar mass ultracompact objects in data obtained during Advanced LIGO's second observing run. In contrast to a previous search of Advanced LIGO data from the first observing run, this search includes the effects of component spin on the gravitational waveform. We identify no viable gravitational-wave candidates consistent with subsolar mass ultracompact binaries with at least one component between 0.2  M_{⊙}-1.0  M_{⊙}. We use the null result to constrain the binary merger rate of (0.2  M_{⊙}, 0.2  M_{⊙}) binaries to be less than 3.7×10^{5}  Gpc^{-3} yr^{-1} and the binary merger rate of (1.0  M_{⊙}, 1.0  M_{⊙}) binaries to be less than 5.2×10^{3}  Gpc^{-3} yr^{-1}. Subsolar mass ultracompact objects are not expected to form via known stellar evolution channels, though it has been suggested that primordial density fluctuations or particle dark matter with cooling mechanisms and/or nuclear interactions could form black holes with subsolar masses. Assuming a particular primordial black hole (PBH) formation model, we constrain a population of merging 0.2  M_{⊙} black holes to account for less than 16% of the dark matter density and a population of merging 1.0  M_{⊙} black holes to account for less than 2% of the dark matter density. We discuss how constraints on the merger rate and dark matter fraction may be extended to arbitrary black hole population models that predict subsolar mass binaries.

P2708Clopidogrel versus ticagrelor on coronary microvascular and peripheral endothelial function after non-ST elevation acute coronary syndrome: a randomised trial

Background

Ticagrelor has been shown to reduce microvascular injury and improve peripheral endothelial function compared to clopidogrel in ST-elevation myocardial infarction and stable patients. However, comparable data is lacking in non-ST elevation acute coronary syndromes (NSTE-ACS).

Purpose

To investigate the effects of clopidogrel versus ticagrelor on coronary microvascular function and peripheral endothelial function in NSTE-ACS patients.

Methods

Patients hospitalised for NSTE-ACS were prospectively randomised 1:1 to clopidogrel (300mg loading then 75mg daily) or ticagrelor (180mg loading then 90mg twice-daily). Coronary microvascular function was assessed with index of microcirculatory resistance (IMR) in the infarct related artery (IRA) and non-IRA before and after percutaneous coronary intervention (PCI) using a standard pressure-temperature coronary wire. Peripheral endothelial function was assessed with flow-mediated vasodilation (FMD) of the brachial artery, performed on admission prior to antiplatelet loading and again before discharge, using a pneumatic cuff and 10MHz linear ultrasound transducer.

Results

A total of 40 patients were included for analysis (Figure 1). Median age was 53.5 (IQR 49.0–61.5) years, 35 (87.5%) were male, 11 (27.5%) had diabetes, 19 (47.5%) were smokers. Median peak troponin T was 527 (175–1006.5) ng/L, median GRACE score 91.5 (78.3–103.3) and median SYNTAX score 13 (6–20). Baseline characteristics were similar between both groups. There was no significant difference in the median baseline IMR between the 2 groups in both the IRA (clopidogrel 14.4 [IQR 12.2–18.6] vs ticagrelor 20.8 [11.3–27.4], p=0.22) and non-IRA (14.0 [11.0–22.0] vs 14.0 [10.0–29.5] respectively, p=0.74). 28 patients underwent PCI to the IRA (12 clopidogrel, 16 ticagrelor). There was no significant difference in the median post-PCI IMR between the 2 groups (19.5 [14.5–24.5] vs 29.0 [19.0–35.6] respectively, p=0.11). However, there was significant worsening of post-PCI compared with pre-PCI IMR (19.5 vs 15.0, p=0.049) in the clopidogrel group but not in the ticagrelor group (29.0 vs 25.4, p=0.47). FMD was performed in 23 patients (9 clopidogrel, 14 ticagrelor). Admission median %FMD (change in post-stimulus diameter as a percentage of the baseline diameter) was similar between the 2 groups (13.2% [10.1–17.6] vs 12.2% [10.2–15.8] respectively, p=0.41). There was a trend towards higher median pre-discharge %FMD in the ticagrelor group (12.8% [12.2–18.0]) compared to the clopidogrel group (10.4% [9.5–11.2], p=0.09). There was a trend towards lower pre-discharge %FMD compared to admission in the clopidogrel group (10.4% vs 13.2%, p=0.05) but not the ticagrelor group (12.8% vs 12.2%, p=0.43).

Figure 1

Conclusions

In our NSTE-ACS patients undergoing PCI, ticagrelor resulted in less disruption of coronary microvascular function and may also have beneficial effects on peripheral endothelial function compared to clopidogrel.

Acknowledgement/Funding

Dr. James Xu is funded by a post-graduate scholarship from the Australian Government Research Training Program (RTP)

Can Administrative Data Improve the Performance of Cancer Clinical Trial Economic Analyses?

PURPOSE

Trial economic analyses, such as cost-effectiveness analysis, often rely on trial-collected data, which are burdensome and expensive to collect and may be incomplete. In contrast, administrative databases systematically collect health system encounters. We investigated whether administrative data could improve the performance of cancer trial economic analysis.

METHODS

Health administrative data were probabilistically linked to Ontario patient data from the Canadian Cancer Trials Group CO.17 trial (n = 572), which evaluated cetuximab plus best supportive care (75 linked Ontario patients) versus best supportive care alone (73 patients) in previously treated metastatic colorectal cancer. Trial-collected resource utilization data and vital status were compared with administrative data. Cost effectiveness in 2007 Canadian dollars was determined with bootstrap incremental cost-effectiveness ratio (ICER) CIs.

RESULTS

Up to trial date of last contact, administrative data vital status was concordant in more than 96%. Twenty-nine subsequent deaths occurred. Up to trial last contact, there were 50 net additional hospitalizations in administrative data and 33 net additional emergency department visits. Total costs were $3,023,034 for the cetuximab group and $1,191,118 for the control group up to trial last contact. The ICER was $211,128 per life-year gained (90% CI, $101,396 to $694,950) up to trial last contact and $164,378 (90% CI, -$138,260 to $644,555) up to administrative data last contact. ICER estimates were similar to the analysis using trial-collected data.

CONCLUSION

Administrative data were more complete than trial data for hospital encounters, a key cost driver in economic analysis. There was a longer follow-up. This demonstrates the potential of administrative data to relieve the burden of collecting key data in cancer trials, which represents a considerable effort and expense.

Tests of General Relativity with GW170817

The recent discovery by Advanced LIGO and Advanced Virgo of a gravitational wave signal from a binary neutron star inspiral has enabled tests of general relativity (GR) with this new type of source. This source, for the first time, permits tests of strong-field dynamics of compact binaries in the presence of matter. In this Letter, we place constraints on the dipole radiation and possible deviations from GR in the post-Newtonian coefficients that govern the inspiral regime. Bounds on modified dispersion of gravitational waves are obtained; in combination with information from the observed electromagnetic counterpart we can also constrain effects due to large extra dimensions. Finally, the polarization content of the gravitational wave signal is studied. The results of all tests performed here show good agreement with GR.

The role of Olfaction in MCH-regulated spontaneous maternal responses

Melanin concentrating hormone (MCH) is involved in the initiation of maternal behavior during the postpartum period. Virgin females also display some aspects of maternal care independent of the hormonal and neurochemical changes associated with pregnancy and parturition. Maternal behavior in virgin females is triggered by pups-generated chemosensory signals. We therefore examined the role of MCH in maternal-related behaviors in virgin mice and whether it involves chemosensory mechanisms. We used mice with germline knock-out of MCH receptor (MCHR1 KO) and mice with conditional ablation of MCH neurons (MCH cKO) using Cre-inducible diphtheria toxin (iDTR) system. We report that germline deletion of MCHR1 and ablation of MCH neurons impair spontaneous maternal behavior that is induced upon pups' exposure. The latency and duration to retrieve pups by MCHR1 KO and MCH cKO mice are longer than their control littermate mice. In support of this finding, we found that in the three-chamber social test, both MCHR1 KO and MCH cKO mice display a lack of interest in interacting with pups. Strikingly, however, we found that while MCHR1 KO mice were unable to detect pups' chemosensory signals and displayed impairment in general olfactory discrimination, MCH cKO mice exhibited normal olfactory function. Our findings indicate that the lack of MCHR1 or of normal MCH levels causes defects in maternal behavior in non-sensitized virgin mice, and that disruption of the olfactory signaling might not count for these defects.

Constraining the p-Mode-g-Mode Tidal Instability with GW170817

We analyze the impact of a proposed tidal instability coupling p modes and g modes within neutron stars on GW170817. This nonresonant instability transfers energy from the orbit of the binary to internal modes of the stars, accelerating the gravitational-wave driven inspiral. We model the impact of this instability on the phasing of the gravitational wave signal using three parameters per star: an overall amplitude, a saturation frequency, and a spectral index. Incorporating these additional parameters, we compute the Bayes factor (lnB_{!pg}^{pg}) comparing our p-g model to a standard one. We find that the observed signal is consistent with waveform models that neglect p-g effects, with lnB_{!pg}^{pg}=0.03_{-0.58}^{+0.70} (maximum a posteriori and 90% credible region). By injecting simulated signals that do not include p-g effects and recovering them with the p-g model, we show that there is a ≃50% probability of obtaining similar lnB_{!pg}^{pg} even when p-g effects are absent. We find that the p-g amplitude for 1.4  M_{⊙} neutron stars is constrained to less than a few tenths of the theoretical maximum, with maxima a posteriori near one-tenth this maximum and p-g saturation frequency ∼70  Hz. This suggests that there are less than a few hundred excited modes, assuming they all saturate by wave breaking. For comparison, theoretical upper bounds suggest ≲10^{3} modes saturate by wave breaking. Thus, the measured constraints only rule out extreme values of the p-g parameters. They also imply that the instability dissipates ≲10^{51}  erg over the entire inspiral, i.e., less than a few percent of the energy radiated as gravitational waves.

Do doctors who order more routine medical tests diagnose more cancers? A population-based study from Ontario Canada

Background

The overuse of medical tests leads to higher costs, wasting of resources, and the potential for overdiagnosis of disease. This study was designed to determine whether the patients of family doctors who order more routine medical tests are diagnosed with more cancers.

Method

A retrospective population‐based cross‐sectional study using administrative health care data in Ontario Canada. We investigated the ordering of 23 routine laboratories and imaging tests 2008‐20012 by 6849 Ontario family physicians on their 4.9 million rostered adult patients. We compared physicians’ test utilization and calculated case‐mix adjusted observed to expected (O:E) utilization ratios to categorize physicians as Typical, Higher or Lower testers. Age‐sex standardized rates (cases/10 000 patient years) and Rate Ratios were determined for cancers of the thyroid, prostate, breast, lymphoma, kidney, melanoma, uterus, ovary, lung, esophagus, and pancreas for each tester group.

Results

There was wide variation in the use of the 23 tests by Ontario physicians. 26% and 24% of physicians were deemed Higher Testers for laboratory and imaging tests, while 41% and 38% were Typical Testers. The patients of higher test users were diagnosed with more cancers of thyroid (laboratory [RR 1.61, 95% CI 1.39‐1.87] and imaging [RR 2.08, 95% CI 0.88‐2.30]) and prostate (laboratory [RR 1.10, 95% CI 1.03‐1.18] and imaging [RR 1.05, 95% CI 1.00‐1.10]).

Conclusion

There is a wide variation in the ordering of routine and common medical tests among Ontario family doctors. The patients of higher testers were diagnosed with more thyroid and prostate cancers.

Search for Subsolar-Mass Ultracompact Binaries in Advanced LIGO's First Observing Run

We present the first Advanced LIGO and Advanced Virgo search for ultracompact binary systems with component masses between 0.2  M_{⊙}-1.0  M_{⊙} using data taken between September 12, 2015 and January 19, 2016. We find no viable gravitational wave candidates. Our null result constrains the coalescence rate of monochromatic (delta function) distributions of nonspinning (0.2  M_{⊙}, 0.2  M_{⊙}) ultracompact binaries to be less than 1.0×10^{6}  Gpc^{-3}  yr^{-1} and the coalescence rate of a similar distribution of (1.0  M_{⊙}, 1.0  M_{⊙}) ultracompact binaries to be less than 1.9×10^{4}  Gpc^{-3}  yr^{-1} (at 90% confidence). Neither black holes nor neutron stars are expected to form below ∼1  M_{⊙} through conventional stellar evolution, though it has been proposed that similarly low mass black holes could be formed primordially through density fluctuations in the early Universe and contribute to the dark matter density. The interpretation of our constraints in the primordial black hole dark matter paradigm is highly model dependent; however, under a particular primordial black hole binary formation scenario we constrain monochromatic primordial black hole populations of 0.2  M_{⊙} to be less than 33% of the total dark matter density and monochromatic populations of 1.0  M_{⊙} to be less than 5% of the dark matter density. The latter strengthens the presently placed bounds from microlensing surveys of massive compact halo objects (MACHOs) provided by the MACHO and EROS Collaborations.

BOS is associated with decreased HDAC2 from steroid resistant lymphocytes in the small airways

Immunosuppression therapies including corticosteroids fail to prevent bronchiolitis obliterans syndrome (BOS), primarily a disease of the small airways, following lung transplantation. We reported increases in steroid-resistant proinflammatory lymphocytes and their loss of histone deacetylase 2 (HDAC2), an important mediator of steroid action, in the blood of stable lung transplant recipients. We noted similar increases in the steroid-resistant lymphocytes in both the blood and small airways in BOS compared with the large airways. We hypothesized that these small airway cells would also exhibit a loss of HDAC2, and that these changes could be reversed by treatment with theophylline (HDAC2 activator). Blood, bronchoalveolar lavage and large and small airway brushings were collected from lung transplant patients with BOS (n = 12) or stable lung function (n = 18) and healthy aged-matched controls (n = 13). Intracellular proinflammatory cytokines [interferon (IFN-γ) and tumour necrosis factor (TNF)-α and HDAC2 were measured in CD8⁺ T, natural killer (NK) T-like and NK cells from cultured small airway brushings ± 5 mg/l theophylline ± 1 µM prednisolone using flow cytometry. Increased small airway CD8 T, NK T-like and NK cells were identified in BOS versus stable transplant and controls. In BOS, these cells exhibited increased IFN-γ/TNF-α and a loss of HDAC2. HDAC2 expression by small airway CD8⁺ T cells correlated with forced expiratory volume in 1 s (FEV₁ ) (R = 0·880, P = 0·031). Theophylline and prednisolone synergistically up-regulated HDAC2 in CD8⁺ T cells. BOS is associated with loss of HDAC2 from steroid-resistant proinflammatory CD8⁺ T, NK T-like and NK cells in the small airways. Therapeutically increasing HDAC2 in these lymphocytes may reduce steroid resistance and improve graft survival.

Can administrative data improve the performance of clinical trial economic analyses?

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Background: Economic analyses of trials often rely on trial-collected health resource utilization data, which is expensive and may be incompletely recorded. We investigated whether routinely collected health administrative data (RCD) can be utilized to improve trial economic analysis performance. Methods: Health administrative data was probabilistically linked to Ontario patient data from the Canadian Cancer Trials Group CO.17 trial (n = 572), evaluating cetuximab plus best supportive care (n = 75 linked Ontario patients) versus best supportive care alone (n = 73). Completeness of trial data was compared to RCD. Cost-effectiveness in 2007 Canadian dollars was determined using RCD up to trial date of last contact (DOLC), and up to RCD DOLC. Incremental cost effectiveness ratio (ICER) confidence intervals (CI) were determined using bootstrapping with 5000 iterations. Cost-effectiveness acceptability curves were determined. Sensitivity analyses were performed. Results: Among 148 Ontario patients, up to trial DOLC, RCD vital status was concordant in > 96%. 29 deaths occurred after trial DOLC. Up to trial DOLC there were 34 net additional hospitalizations in RCD, and 28 net additional emergency room visits. Using RCD, total cetuximab group costs were $3,023,034, and $1,191,118 for best supportive care alone up to trial DOLC. Cost difference was driven by cetuximab drug costs ($1,531,370). Using RCD, the ICER was $211,128 per life-year gained (90% CI: $101,396, $694,950) when data was limited to trial DOLC, and $164,378 (90% CI: -$138,260, $644,555) using routinely collected data DOLC. ICER estimates were similar to the original economic analysis using trial-collected data ($199,742 (95% CI $125,973, $652,492)). Estimates were robust in sensitivity analysis. Conclusions: Administrative data were more complete than trial-collected utilization data, even under optimal conditions. There was also longer follow-up. We found that cost differences were robust to varying costing assumptions. Our findings demonstrate the potential of administrative data sources to relieve institutions, sponsors and patients from the burden of collecting key utilization information which requires considerable effort and cost.

GW170817: Measurements of Neutron Star Radii and Equation of State

On 17 August 2017, the LIGO and Virgo observatories made the first direct detection of gravitational waves from the coalescence of a neutron star binary system. The detection of this gravitational-wave signal, GW170817, offers a novel opportunity to directly probe the properties of matter at the extreme conditions found in the interior of these stars. The initial, minimal-assumption analysis of the LIGO and Virgo data placed constraints on the tidal effects of the coalescing bodies, which were then translated to constraints on neutron star radii. Here, we expand upon previous analyses by working under the hypothesis that both bodies were neutron stars that are described by the same equation of state and have spins within the range observed in Galactic binary neutron stars. Our analysis employs two methods: the use of equation-of-state-insensitive relations between various macroscopic properties of the neutron stars and the use of an efficient parametrization of the defining function p(ρ) of the equation of state itself. From the LIGO and Virgo data alone and the first method, we measure the two neutron star radii as R_{1}=10.8_{-1.7}^{+2.0}  km for the heavier star and R_{2}=10.7_{-1.5}^{+2.1}  km for the lighter star at the 90% credible level. If we additionally require that the equation of state supports neutron stars with masses larger than 1.97  M_{⊙} as required from electromagnetic observations and employ the equation-of-state parametrization, we further constrain R_{1}=11.9_{-1.4}^{+1.4}  km and R_{2}=11.9_{-1.4}^{+1.4}  km at the 90% credible level. Finally, we obtain constraints on p(ρ) at supranuclear densities, with pressure at twice nuclear saturation density measured at 3.5_{-1.7}^{+2.7}×10^{34}  dyn cm^{-2} at the 90% level.

Population survival impact of new targeted and immune based therapies for metastatic or unresectable melanoma

IntroductionNew classes of drugs for metastatic or unresectable melanoma (MM) have shown improved survival in randomized trials (e.g., anti-CTLA-4, anti-PD-1, BRAF/MEK inhibitors). We sought to describe uptake of these new drugs and their impact on population-based survival outcomes of MM. Objectives and ApproachWe sought to describe uptake of these new drugs and their impact on population-based survival outcomes of MM. This was a retrospective, population-based cohort study of all treated MM in Ontario 2007-2015. Administrative data sources from the Institute for Clinical Evaluative Sciences (ICES) were utilized. Within ICES, cutaneous and non-cutaneous primaries were identified in the Ontario Cancer Registry. Administrative sources from Cancer Care Ontario, Ministry of Health and Long-Term Care, and Canadian Institute for Health Information identified patients treated with palliative systemic therapy, radiotherapy and metastatectomy. Temporal trends in utilization and survival were investigated. Survival by drug class was described. ResultsWe identified 2,793 MM patients. First treatment was systemic therapy (46%), radiotherapy (41%) or metastatectomy (14%). MM patient number increased from 270 in 2007 to 418 in 2015. Systemic treatment rose from 125 MM first treated in 2007 to 343 in 2015. New drug treatments increased from <6% of reported first-line regimens in 2007 to 82\% in 2015. 1-year and 2-year overall survival (OS) was 28% and 15% respectively for all MM in 2007-2009, rising to 46% and 35% for 2014-2015 (logrank p<0.001; adjusted hazard ratio (AHR) 0.56, 95% confidence interval (CI): (0.49,0.63)). Survival gains were largely in the subset treated primarily systemically, where new drugs were increasingly utilized (2-year OS 16% 2007-2009 vs. 44% 2014-2015 logrank p<0.001; AHR 0.46, 95% CI: (0.38,0.56)). Conclusion/ImplicationsUtilization of systemic therapy for MM has increased considerably in routine practice during 2007-2015; at least some of this increase relates to use of novel agents since 2011. In line with randomized trial findings, new drug adoption was associated with substantial increases in population-based MM survival.