•Chihuahuan, Sonoran and Mojave Deserts vary in precipitation amount and seasonal distribution.•Due to hydrologic losses, ET was a better metric of ecosystem-available water than ...precipitation.•Ecosystem water use efficiency (GEP/ET) did not differ between winter and summer.•Due to lower respiration, winter seasons were critical for net carbon uptake.•Reduced 21st century winter precipitation reduced the carbon sink ∼6.8TgCyr1 in these 3 deserts.
Global-scale studies suggest that dryland ecosystems dominate an increasing trend in the magnitude and interannual variability of the land CO2 sink. However, such model-based analyses are poorly constrained by measured CO2 exchange in open shrublands, which is the most common global land cover type, covering ∼14% of Earth’s surface. Here we evaluate how the amount and seasonal timing of water availability regulate CO2 exchange between shrublands and the atmosphere. We use eddy covariance data from six US sites across the three warm deserts of North America with observed ranges in annual precipitation of ∼100–400mm, annual temperatures of 13–18°C, and records of 2–8 years (33 site-years in total). The Chihuahuan, Sonoran and Mojave Deserts present gradients in both mean annual precipitation and its seasonal distribution between the wet-winter Mojave Desert and the wet-summer Chihuahuan Desert. We found that due to hydrologic losses during the wettest summers in the Sonoran and Chihuahuan Deserts, evapotranspiration (ET) was a better metric than precipitation of water available to drive dryland CO2 exchange. In contrast with recent synthesis studies across diverse dryland biomes, we found that NEP could not be directly predicted from ET due to wintertime decoupling of the relationship between ecosystem respiration (Reco) and gross ecosystem productivity (GEP). Ecosystem water use efficiency (WUE=GEP/ET) did not differ between winter and summer. Carbon use efficiency (CUE=NEP/GEP), however, was greater in winter because Reco returned a smaller fraction of carbon to the atmosphere (23% of GEP) than in summer (77%). Combining the water-carbon relations found here with historical precipitation since 1980, we estimate that lower average winter precipitation during the 21st century reduced the net carbon sink of the three deserts by an average of 6.8TgC yr1. Our results highlight that winter precipitation is critical to the annual carbon balance of these warm desert shrublands.
Abstract
The emergence of insulating ferromagnetic phase in iron oxychalcogenide chain system has been recently argued to be originated by
interorbital
hopping mechanism. However, the practical ...conditions for the stability of such mechanism still prevents the observation of ferromagnetic in many materials. Here, we study the stability range of such ferromagnetic phase under modifications in the crystal fields and electronic correlation strength, constructing a theoretical phase diagram. We find a rich emergence of phases, including a ferromagnetic Mott insulator, a ferromagnetic orbital-selective Mott phase, together with antiferromagnetic and ferromagnetic metallic states. We characterize the stability of the ferromagnetic regime in both the Mott insulator and the ferromagnetic orbital-selective Mott phase forms. We identify a
large
stability range in the phase diagram at both intermediate and strong electronic correlations, demonstrating the capability of the interorbital hopping mechanism in stabilizing ferromagnetic insulators. Our results may enable additional design strategies to expand the relatively small family of known ferromagnetic insulators.
Abstract
Background
Hospital-onset (HO) carbapenem-resistant Enterobacterales (CRE) infections are increasing; recently, the Centers for Disease Control and Prevention (CDC) reported a 35% increase ...during the COVID-19 pandemic. We evaluated the impact of HO CRE blood stream infections (BSI) on outcomes compared to community-onset (CO) CRE BSI.
Methods
Patients prospectively enrolled in CRACKLE-2 from 56 hospitals in 10 countries between April 30, 2016 to November 30, 2019 with a qualifying CRE bloodstream culture were eligible. Infections were defined per CDC guidelines as CO when the culture was obtained immediately prior to admission or through the first three days of hospitalization, and HO when the culture was obtained on or after the fourth day of admission. Categorical variables were tested using a chi-square test; continuous variable distributions were compared using Wilcoxon rank sum and Kruskal Wallis tests, as appropriate. The primary outcome was desirability of outcome ranking (DOOR) 30 days after index culture. Difference in 30-day mortality was calculated with 95% confidence intervals (CI).
Results
Among 891 patients with CRE BSI (Table 1), 65% of BSIs were hospital-onset (582/891). Compared to those with CO CRE, patients with HO CRE were younger (median 60 Q1 42, Q3 70 years vs 65 52, 74; p< 0.001), had lower Charlson comorbidity score (median 2 1, 4 versus 3 1, 5; p=0.002), and more often had Pitt bacteremia sore ≥4, indicative of critical illness, (47% versus 32%; p=< 0.001). ICU admission prior to first culture was associated with HO BSI (68% versus 42%, p< 0.001). Distribution of DOOR outcome at 30 days is shown in Figure 1. The probability of a better DOOR outcome in a randomly selected patient with CO BSI compared to a patient with HO BSI is 60.6% (95% CI: 56.8-64.3%). Mortality at 30-days was 11.6% higher in HO BSI than CO BSI (95% CI: 5.7, 17.6%, p=0.0003). A Kaplan-Meier curve of all-cause 30-day mortality is in Figure 2Figure 1:Distribution of Desirability of Outcome Ranking (DOOR) Categories by Infection Onset
Desirability of outcome ranking at 30-days. Events evaluated included 1) deleterious effects, including absence of clinical response, prolonged hospitalization (>30 days following first positive culture), or readmission within 30 days; 2) any adverse events including renal failure or C. difficile infection; and 3) mortality at 30 days. Two subjects (1 in hospital onset group and 1 in community onset group) missing 30-day DOOR due to missing disposition information are not included in the figure.Figure 2:30-day Survival Plot by Infection Onset
Two subjects (1 in hospital onset group and 1 in community onset group) are excluded from the figure due to missing mortality outcome information. One subject in the hospital onset group died on day 30 and is still considered at risk in the figure.
Conclusion
HO CRE BSIs are associated with worse outcomes than CO CRE BSIs; this unique population warrants special attention. As CRE often contain mobile genetic elements that facilitate horizontal transfer, close monitoring of HO CRE rates and optimizing hospital infection prevention methods are critical to prevent added morbidity and mortality.
Disclosures
Yohei Doi, MD, PHD, bioMerieux: Advisor/Consultant|FujiFilm: Advisor/Consultant|Gilead: Advisor/Consultant|Gilead: Honoraria|GSK: Advisor/Consultant|Meiji Seika Pharma: Advisor/Consultant|Moderna: Advisor/Consultant|Moderna: Honoraria|MSD: Advisor/Consultant|MSD: Honoraria|Shionogi: Advisor/Consultant|Shionogi: Grant/Research Support|Shionogi: Honoraria Michael J. Satlin, MD, AbbVie: IDMC member|Biomerieux: Grant/Research Support|Merck: Grant/Research Support|SNIPRBiome: Grant/Research Support Vance G. Fowler, MD, MHS, Amphliphi Biosciences, Integrated Biotherapeutics; C3J, Armata, Valanbio; Akagera, Aridis, Roche, Astra Zeneca: Advisor/Consultant|Genentech, Regeneron, Deep Blue, Basilea, Janssen;: Grant/Research Support|Infectious Diseases Society of America: Honoraria|MedImmune, Allergan, Pfizer, Advanced Liquid Logics, Theravance, Novartis, Merck; Medical Biosurfaces; Locus; Affinergy; Contrafect; Karius;: Grant/Research Support|Novartis, Debiopharm, Genentech, Achaogen, Affinium, Medicines Co., MedImmune, Bayer, Basilea, Affinergy, Janssen, Contrafect, Regeneron, Destiny,: Advisor/Consultant|Sepsis diagnostic: Patent pending|UpToDate: Royalties|Valanbio and ArcBio: Stock Options David van Duin, MD, PhD, Entasis: Advisor/Consultant|Merck: Advisor/Consultant|Merck: Grant/Research Support|Pfizer: Advisor/Consultant|Pfizer: Honoraria|Qpex: Advisor/Consultant|Roche: Advisor/Consultant|Shionogi: Advisor/Consultant|Shionogi: Grant/Research Support|Union: Advisor/Consultant|Utility: Advisor/Consultant
The 2013-2014 approvals of new direct-acting antiviral (DAA) therapies for hepatitis C virus (HCV) infection have engendered a paradigm shift in HCV treatment and management, offering the potential ...for a cure at a population level. The availability of the highly effective and relatively safe DAAs prompted revisions to guidance recommendations based on new clinical trial evidence. In the context of this paradigm shift and considerations of the costs associated with the new DAAs, managed care professionals face new questions and challenges regarding HCV treatment and management approaches. To address the continuing education needs of this group, PRIME Education, Inc. (PRIME) conducted a symposium on HCV at the 27th Annual Meeting Expo of the Academy of Managed Care Pharmacy. Moderated by Michael R. Stinchon, Jr., RPh, the program panel featured 2 internationally recognized leaders in hepatitis C treatment and research: Norah Terrault, MD, MPH, and Alex Monto, MD.
To summarize the educational symposium presentations and discussions.
This article is organized by key questions that the panelists and attendees raised for discussion during the 2-hour symposium. The questions addressed methods for assessing liver fibrosis; comprehensive patient assessment to inform treatment decisions; the influence of viral load on decisions about treatment duration; the role of ribavirin in optimizing treatment efficacy; unmet treatment needs for patients with HCV genotype 3 or advanced liver disease; and managed care strategies for patient education, adherence promotion, and care coordination. In answering attendee questions on these issues, the expert panelists presented established evidence, and recognizing limitations to current evidence and guidance recommendations, they discussed applications of clinical judgment and offered their views and practices regarding individualized care for patients with HCV.
In response to questions about the utility of noninvasive methods for assessing liver fibrosis, the expert panel presented a comparative overview of the methodology, accuracy, risks, limitations, and costs of noninvasive tests and liver biopsy. Discussion highlighted the strengths of noninvasive methods for diagnosing advanced disease and cirrhosis and the methods' limitations that pose barriers to ensuring that patients receive necessary antiviral therapy. Based on guidance recommendations, treatment should be prioritized in patients with advanced fibrosis or cirrhosis (Metavir score F3 to F4). While acknowledging the importance of this recommendation, the symposium panelists also argued that making effective decisions about whom, and when, to treat requires a more comprehensive clinical approach to patient assessment and adjusting recommended priorities according to individual patient considerations. This approach involves evaluating outcomes such as extrahepatic complications, including those affecting quality of life, functional status, and work productivity. In response to questions regarding decisions about DAA therapy duration based on viral load, the panel engaged the audience in thinking critically about evidence-based cutoff values and natural fluctuations of HCV RNA concentrations. Discussions centered on the importance of clinical judgment to ensure that the treatment duration promotes the highest efficacy and avoids risks of relapse. The panel responded to several audience questions about the role of ribavirin in new DAA regimens. Evidence-based presentations and discussions focused on patient-specific factors that must be considered to inform effective decisions about adding ribavirin. The panel took a similar approach to answering questions about emerging challenges and the difficult-to-treat populations of patients with HCV genotype 3 or advanced liver disease. The symposium concluded with presentation of, and discussion on, managed care strategies for educating patients about appropriate HCV medication use, improving adherence, and coordinating care provided by the interprofessional team.
The availability of new DAAs for HCV raises new questions and challenges for managed care professionals, especially regarding prioritizing patients for immediate therapy as well as treatment and management approaches that account for the needs of individual patients and subpopulations. The educational symposium summarized in this article directly addressed key questions and challenges through presentations of evidence, guidance recommendations, and interactive discussions on the views and practices of international leaders in HCV treatment and research.
Considering model Hamiltonians that respect the symmetry properties of the pnictides, it is argued that pairing interactions that couple electrons in different orbitals with an orbital-dependent ...pairing strength inevitably lead to interband pairing matrix elements, at least in some regions of the Brillouin zone. Such interband pairing has not been considered of relevance in multiorbital systems in previous investigations. It is also observed that if, instead, a purely intraband pairing interaction is postulated, this requires that the pairing operator has the form k= fkdk,, d k,, , where labels the orbitals considered in the model and fk arises from the spatial location of the coupled electrons or holes. This means that the gaps at two different Fermi surfaces involving momenta kF and kF can only differ by the ratio fkF / fkF and that electrons in different orbitals must be subject to the same pairing attraction, thus, requiring fine tuning. These results suggest that previously neglected interband pairing tendencies could actually be of relevance in a microscopic description of the pairing mechanism in the pnictides.
PDF
