Field-warmed soil carbon changes imply high 21st-century modeling uncertainty

The feedback between planetary warming and soil carbon loss has been the focus of considerable scientific attention in recent decades, due to its potential to accelerate anthropogenic climate change. The soil carbon temperature sensitivity is traditionally estimated from short-term respiration measurements – either from laboratory incubations that are artificially manipulated or from field measurements that cannot distinguish between plant and microbial respiration. To address these limitations of previous approaches, we developed a new method to estimate soil temperature sensitivity (Q10) of soil carbon directly from warming-induced changes in soil carbon stocks measured in 36 field experiments across the world. Variations in warming magnitude and control organic carbon percentage explained much of field-warmed organic carbon percentage (R2  =  0.96), revealing Q10 across sites of 2.2 [1.6, 2.7] 95 % confidence interval (CI). When these field-derived Q10 values were extrapolated over the 21st century using a post hoc correction of 20 Coupled Model Intercomparison Project Phase 5 (CMIP5) Earth system model outputs, the multi-model mean soil carbon stock changes shifted from the previous value of 88 ± 153 Pg carbon (weighted mean ± 1 SD) to 19 ± 155 Pg carbon with a Q10-driven 95 % CI of 248 ± 191 to −95 ± 209 Pg carbon. On average, incorporating the field-derived Q10 values into Earth system model simulations led to reductions in the projected amount of carbon sequestered in the soil over the 21st century. However, the considerable parameter uncertainty led to extremely high variability in soil carbon stock projections within each model; intra-model uncertainty driven by the field-derived Q10 was as great as that between model variation. This study demonstrates that data integration should capture the variation of the system, as well as mean trends

GCH1 haplotypes and cardiovascular risk in HIV

Heightened systemic inflammation contributes to cardiovascular (CVD) events in people living with HIV (PLWH), though not all PLWH develop CVD, thus suggesting a genetic modifying role. We examined GCH1 polymorphisms, which have been associated with reduced endothelial function in European populations with CVD and increased inflammation, in a racially diverse cohort of U.S. PLWH initiating antiretroviral therapy (ART). GCH1 polymorphisms differed by race and were not associated flow-mediated dilation or carotid intima media thickness before or after 48 weeks of ART

Prescribers\u27 Satisfaction with Delivering Medications for Opioid Use Disorder

BACKGROUND: Expanding access to medications for opioid use disorder (MOUD), such as buprenorphine and extended release (XR) naltrexone, is critical to addressing the US opioid epidemic, but little is known about prescriber satisfaction with delivering these two types of MOUD. The current study describes the satisfaction of prescribers delivering buprenorphine and XR-naltrexone while examining whether satisfaction is associated with current patient census and organizational environment. METHODS: As part of a cluster randomized clinical trial (RCT) focused on expanding access to medication for opioid use disorder, 41 MOUD prescribers in Florida, Ohio, and Wisconsin completed a web-based survey. The survey included measures of prescriber satisfaction with delivering buprenorphine treatment and XR-naltrexone. In addition, the survey measured several prescriber characteristics and their perceptions of the organizational environment. RESULTS: Prescribers were generally satisfied with their work in delivering these two types of MOUD. Prescribers reporting a greater number of patients (r = .46, p = .006), those who would recommend the center to others (r = .56, p \u3c .001), and those reporting positive relationships with staff (r = .56, p \u3c .001) reported significantly greater overall satisfaction with delivering buprenorphine treatment. Prescribers who more strongly endorsed feeling overburdened reported lower overall buprenorphine satisfaction (r = -.37, p = .02). None of the prescriber characteristics or perceptions of the organizational environment were significantly associated with overall satisfaction with delivering XR-naltrexone treatment. CONCLUSIONS: The generally high levels of satisfaction with both types of MOUD is notable given that prescriber dissatisfaction can lead to turnover and impact intentions to leave the profession. Future research should continue to explore the prescriber characteristics and organizational factors associated with satisfaction in providing different types of MOUD. REGISTRATION: ClinicalTrials.gov. NCT02926482. Date of registration: September 9, 2016. https://clinicaltrials.gov/ct2/show/NCT02926482

Preserving photon qubits in an unknown quantum state with Knill dynamical decoupling: Towards an all optical quantum memory

The implementation of polarization-based quantum communication is limited by signal loss and decoherence caused by the birefringence of a single-mode fiber. We investigate the Knill dynamical decoupling scheme, implemented using half-wave plates, to minimize decoherence and show that a fidelity greater than 99% can be achieved in absence of rotation error and fidelity greater than 96% can be achieved in presence of rotation error. Such a scheme can be used to preserve any quantum state with high fidelity and has potential application for constructing all optical quantum delay line, quantum memory, and quantum repeater

ASASSN-15pz: Revealing Significant Photometric Diversity among 2009dc-like, Peculiar SNe Ia

We report comprehensive multi-wavelength observations of a peculiar Type Ia-like supernova ("SN Ia-pec") ASASSN-15pz. ASASSN-15pz is a spectroscopic "twin" of SN 2009dc, a so-called "Super-Chandrasekhar-mass" SN, throughout its evolution, but it has a peak luminosity M_B,peak = -19.69 +/- 0.12 mag that is \approx 0.6 mag dimmer and comparable to the SN 1991T sub-class of SNe Ia at the luminous end of the normal width-luminosity relation. The synthesized Ni56 mass of M_Ni56 = 1.13 +/- 0.14 M_sun is also substantially less than that found for several 2009dc-like SNe. Previous well-studied 2009dc-like SNe have generally suffered from large and uncertain amounts of host-galaxy extinction, which is negligible for ASASSN-15pz. Based on the color of ASASSN-15pz, we estimate a host extinction for SN 2009dc of E(B-V)_host=0.12 mag and confirm its high luminosity (M_B, peak[2009dc] \approx -20.3 mag). The 2009dc-like SN population, which represents ~1% of SNe Ia, exhibits a range of peak luminosities, and do not fit onto the tight width-luminosity relation. Their optical light curves also show significant diversity of late-time (>~ 50 days) decline rates. The nebular-phase spectra provide powerful diagnostics to identify the 2009dc-like events as a distinct class of SNe Ia. We suggest referring to these sources using the phenomenology-based "2009dc-like SN Ia-pec" instead of "Super-Chandrasekhar SN Ia," which is based on an uncertain theoretical interpretation.Comment: 21 pages, 16 figures, accepted for publication in Ap

Population-average mediation analysis for zero-inflated count outcomes

Mediation analysis is an increasingly popular statistical method for explaining causal pathways to inform intervention. While methods have increased, there is still a dearth of robust mediation methods for count outcomes with excess zeroes. Current mediation methods addressing this issue are computationally intensive, biased, or challenging to interpret. To overcome these limitations, we propose a new mediation methodology for zero-inflated count outcomes using the marginalized zero-inflated Poisson (MZIP) model and the counterfactual approach to mediation. This novel work gives population-average mediation effects whose variance can be estimated rapidly via delta method. This methodology is extended to cases with exposure-mediator interactions. We apply this novel methodology to explore if diabetes diagnosis can explain BMI differences in healthcare utilization and test model performance via simulations comparing the proposed MZIP method to existing zero-inflated and Poisson methods. We find that our proposed method minimizes bias and computation time compared to alternative approaches while allowing for straight-forward interpretations.Comment: 34 pages, 2 figures, 4 tables, 49 pages of Supplemental material, 2 supplemental figure

Bone mineral density reductions after tenofovir disoproxil fumarate initiation and changes in phosphaturia: a secondary analysis of ACTG A5224s

Background: It is unknown if the greater reductions in bone mineral density (BMD) associated with initiation of tenofovir disoproxil fumarate compared with abacavir in previously untreated HIV-infected participants in the ACTG A5224s clinical trial were associated with potentially worsening tenofovir-related phosphaturia. Methods: We correlated changes in BMD at the hip and spine with changes in phosphaturia [transtubular reabsorption of phosphorus (TRP) and tubular maximum phosphate reabsorption per glomerular filtration rate (TmP/GFR)] from entry through week 96 in those initiating tenofovir ( n  =   134) versus abacavir ( n  =   135) with efavirenz or atazanavir/ritonavir in A5224s. We also correlated changes in BMD with tenofovir AUC measured between weeks 4 and 24. Results: Changes in TRP and TmP/GFR through week 96 between the tenofovir and abacavir arms were not significantly different (both P  ≥   0.70) and did not differ with use of efavirenz versus atazanavir/ritonavir. There were no significant correlations between changes in either TRP or TmP/GFR and with either hip or spine BMD in the tenofovir arms. Tenofovir AUC was significantly correlated with changes in hip BMD, but not spine BMD, at week 24 ( r  =   -0.22, P  =   0.028) and week 48 ( r  =   -0.26, P  =   0.010), but not at week 96 ( r  =   -0.14, P  =   0.18). Conclusions: Changes in phosphaturia were not different between the tenofovir and abacavir arms in A5224s. Changes in hip and spine BMD with tenofovir were not related to changes in phosphaturia. However, tenofovir exposure was weakly associated with changes in hip BMD through week 48

Effective recruitment of participants to a phase I study using the internet and publicity releases through charities and patient organisations: analysis of the adaptive study of IL-2 dose on regulatory T cells in type 1 diabetes (DILT1D).

A barrier to the successful development of new disease treatments is the timely recruitment of participants to experimental medicine studies that are primarily designed to investigate biological mechanisms rather than evaluate clinical efficacy. The aim of this study was to analyse the performance of three recruitment sources and the effect of publicity events during the Adaptive study of IL-2 dose on regulatory T cells in type 1 diabetes (DILT1D).This work is funded by the JDRF (9-2011-253), the Wellcome Trust (091157) and the National Institute for Health Research (NIHR) Cambridge Biomedical Research Centre. The research leading to these results has received funding from the European Union’s Seventh Framework Programme (FP7/2007-2013) under grant agreement number 241447 (NAIMIT). The Cambridge Institute for Medical Research (CIMR) is in receipt of a Wellcome Trust Strategic Award (100140).This is the final version of the article. It first appeared from BMC via http://dx.doi.org/10.1186/s13063-015-0583-