California's methane super-emitters.

Methane is a powerful greenhouse gas and is targeted for emissions mitigation by the US state of California and other jurisdictions worldwide1,2. Unique opportunities for mitigation are presented by point-source emitters-surface features or infrastructure components that are typically less than 10 metres in diameter and emit plumes of highly concentrated methane3. However, data on point-source emissions are sparse and typically lack sufficient spatial and temporal resolution to guide their mitigation and to accurately assess their magnitude4. Here we survey more than 272,000 infrastructure elements in California using an airborne imaging spectrometer that can rapidly map methane plumes5-7. We conduct five campaigns over several months from 2016 to 2018, spanning the oil and gas, manure-management and waste-management sectors, resulting in the detection, geolocation and quantification of emissions from 564 strong methane point sources. Our remote sensing approach enables the rapid and repeated assessment of large areas at high spatial resolution for a poorly characterized population of methane emitters that often appear intermittently and stochastically. We estimate net methane point-source emissions in California to be 0.618 teragrams per year (95 per cent confidence interval 0.523-0.725), equivalent to 34-46 per cent of the state's methane inventory8 for 2016. Methane 'super-emitter' activity occurs in every sector surveyed, with 10 per cent of point sources contributing roughly 60 per cent of point-source emissions-consistent with a study of the US Four Corners region that had a different sectoral mix9. The largest methane emitters in California are a subset of landfills, which exhibit persistent anomalous activity. Methane point-source emissions in California are dominated by landfills (41 per cent), followed by dairies (26 per cent) and the oil and gas sector (26 per cent). Our data have enabled the identification of the 0.2 per cent of California's infrastructure that is responsible for these emissions. Sharing these data with collaborating infrastructure operators has led to the mitigation of anomalous methane-emission activity10.

Strong methane point sources contribute a disproportionate fraction of total emissions across multiple basins in the United States.

Understanding, prioritizing, and mitigating methane (CH4) emissions requires quantifying CH4 budgets from facility scales to regional scales with the ability to differentiate between source sectors. We deployed a tiered observing system for multiple basins in the United States (San Joaquin Valley, Uinta, Denver-Julesburg, Permian, Marcellus). We quantify strong point source emissions (>10 kg CH4 h-1) using airborne imaging spectrometers, attribute them to sectors, and assess their intermittency with multiple revisits. We compare these point source emissions to total basin CH4 fluxes derived from inversion of Sentinel-5p satellite CH4 observations. Across basins, point sources make up on average 40% of the regional flux. We sampled some basins several times across multiple months and years and find a distinct bimodal structure to emission timescales: the total point source budget is split nearly in half by short-lasting and long-lasting emission events. With the increasing airborne and satellite observing capabilities planned for the near future, tiered observing systems will more fully quantify and attribute CH4 emissions from facility to regional scales, which is needed to effectively and efficiently reduce methane emissions.

Efficacy, tolerability, and bone density outcomes of elagolix with add-back therapy for endometriosis-associated pain: 12 months of an ongoing randomized phase 3 trial.

BACKGROUND: Elagolix, an approved oral treatment for endometriosis-associated pain, has been associated with hypoestrogenic effects when used as monotherapy. Hormonal add-back therapy has the potential to mitigate these effects. OBJECTIVE: To evaluate efficacy, tolerability, and bone density outcomes of elagolix 200 mg twice daily with 1 mg estradiol /0.5 mg norethindrone acetate (add-back) therapy once daily compared with placebo in premenopausal women with moderate-to-severe endometriosis-associated pain. STUDY DESIGN: This ongoing, 48-month, phase 3 study consists of a 12-month, double-blind period, with randomization 4:1:2 to elagolix 200 mg twice daily with add-back therapy, elagolix 200 mg twice daily monotherapy for 6 months followed by elagolix with add-back therapy, or placebo. The co-primary endpoints were proportion of patients with clinical improvement (termed "responders") in dysmenorrhea and nonmenstrual pelvic pain at month 6. We report 12-month results on efficacy of elagolix with add-back therapy versus placebo in reducing dysmenorrhea, nonmenstrual pelvic pain, dyspareunia, and fatigue. Tolerability assessments include adverse events and change from baseline in bone mineral density. RESULTS: A total of 679 patients were randomized to elagolix with add-back therapy (n=389), elagolix monotherapy (n=97), or placebo (n=193). Compared with patients randomized to placebo, a significantly greater proportion of patients randomized to elagolix with add-back therapy responded with clinical improvement in dysmenorrhea (62.8% versus 23.7%; P≤.001) and nonmenstrual pelvic pain (51.3% versus 36.8%; P≤.001) at 6 months. Compared with placebo, elagolix with add-back therapy produced significantly greater improvement from baseline in 7 hierarchically ranked secondary endpoints including dysmenorrhea (months 12, 6, 3), nonmenstrual pelvic pain (months 12, 6, 3), and fatigue (months 6) (all P<.01). Overall, the incidence of adverse events was 73.8% with elagolix plus add-back therapy and 66.8% with placebo. The rate of severe and serious adverse events did not meaningfully differ between treatment groups. Study drug discontinuations associated with adverse events were low in patients receiving elagolix with add-back therapy (12.6%) and those receiving placebo (9.8%). Patients randomized to elagolix monotherapy exhibited decreases from baseline in bone mineral density of -2.43% (lumbar spine), -1.54% (total hip), and -1.78% (femoral neck) at month 6. When add-back therapy was added to elagolix at month 6, the change from baseline in bone mineral density remained in a similar range of -1.58% to -1.83% at month 12. However, patients who received elagolix plus add-back therapy from baseline exhibited little change from baseline in bone mineral density (<1% change) at months 6 and 12. CONCLUSION: Compared with placebo, elagolix with add-back therapy resulted in significant, clinically meaningful improvement in dysmenorrhea, nonmenstrual pelvic pain, and fatigue at 6 months that continued until month 12 for both dysmenorrhea and nonmenstrual pelvic pain. Elagolix with add-back therapy was generally well tolerated. Loss of bone mineral density at 12 months was greater in patients who received elagolix with add-back therapy than those who received placebo. However, the change in bone mineral density with elagolix plus add-back therapy was < 1% and was attenuated compared with bone loss observed with elagolix monotherapy.

Carbon uptake in Eurasian boreal forests dominates the high-latitude net ecosystem carbon budget.

Arctic-boreal landscapes are experiencing profound warming, along with changes in ecosystem moisture status and disturbance from fire. This region is of global importance in terms of carbon feedbacks to climate, yet the sign (sink or source) and magnitude of the Arctic-boreal carbon budget within recent years remains highly uncertain. Here, we provide new estimates of recent (2003-2015) vegetation gross primary productivity (GPP), ecosystem respiration (Reco ), net ecosystem CO2 exchange (NEE; Reco - GPP), and terrestrial methane (CH4 ) emissions for the Arctic-boreal zone using a satellite data-driven process-model for northern ecosystems (TCFM-Arctic), calibrated and evaluated using measurements from >60 tower eddy covariance (EC) sites. We used TCFM-Arctic to obtain daily 1-km2 flux estimates and annual carbon budgets for the pan-Arctic-boreal region. Across the domain, the model indicated an overall average NEE sink of -850 Tg CO2 -C year-1 . Eurasian boreal zones, especially those in Siberia, contributed to a majority of the net sink. In contrast, the tundra biome was relatively carbon neutral (ranging from small sink to source). Regional CH4 emissions from tundra and boreal wetlands (not accounting for aquatic CH4 ) were estimated at 35 Tg CH4 -C year-1 . Accounting for additional emissions from open water aquatic bodies and from fire, using available estimates from the literature, reduced the total regional NEE sink by 21% and shifted many far northern tundra landscapes, and some boreal forests, to a net carbon source. This assessment, based on in situ observations and models, improves our understanding of the high-latitude carbon status and also indicates a continued need for integrated site-to-regional assessments to monitor the vulnerability of these ecosystems to climate change.

Pan-Arctic soil moisture control on tundra carbon sequestration and plant productivity.

Long-term atmospheric CO2 concentration records have suggested a reduction in the positive effect of warming on high-latitude carbon uptake since the 1990s. A variety of mechanisms have been proposed to explain the reduced net carbon sink of northern ecosystems with increased air temperature, including water stress on vegetation and increased respiration over recent decades. However, the lack of consistent long-term carbon flux and in situ soil moisture data has severely limited our ability to identify the mechanisms responsible for the recent reduced carbon sink strength. In this study, we used a record of nearly 100 site-years of eddy covariance data from 11 continuous permafrost tundra sites distributed across the circumpolar Arctic to test the temperature (expressed as growing degree days, GDD) responses of gross primary production (GPP), net ecosystem exchange (NEE), and ecosystem respiration (ER) at different periods of the summer (early, peak, and late summer) including dominant tundra vegetation classes (graminoids and mosses, and shrubs). We further tested GPP, NEE, and ER relationships with soil moisture and vapor pressure deficit to identify potential moisture limitations on plant productivity and net carbon exchange. Our results show a decrease in GPP with rising GDD during the peak summer (July) for both vegetation classes, and a significant relationship between the peak summer GPP and soil moisture after statistically controlling for GDD in a partial correlation analysis. These results suggest that tundra ecosystems might not benefit from increased temperature as much as suggested by several terrestrial biosphere models, if decreased soil moisture limits the peak summer plant productivity, reducing the ability of these ecosystems to sequester carbon during the summer.

Large and seasonally varying biospheric CO2 fluxes in the Los Angeles megacity revealed by atmospheric radiocarbon.

Measurements of Δ14C and CO2 can cleanly separate biogenic and fossil contributions to CO2 enhancements above background. Our measurements of these tracers in air around Los Angeles in 2015 reveal high values of fossil CO2 and a significant and seasonally varying contribution of CO2 from the urban biosphere. The biogenic CO2 is composed of sources such as biofuel combustion and human metabolism and an urban biospheric component likely originating from urban vegetation, including turf and trees. The urban biospheric component is a source in winter and a sink in summer, with an estimated amplitude of 4.3 parts per million (ppm), equivalent to 33% of the observed annual mean fossil fuel contribution of 13 ppm. While the timing of the net carbon sink is out of phase with wintertime rainfall and the sink seasonality of Southern California Mediterranean ecosystems (which show maximum uptake in spring), it is in phase with the seasonal cycle of urban water usage, suggesting that irrigated urban vegetation drives the biospheric signal we observe. Although 2015 was very dry, the biospheric seasonality we observe is similar to the 2006-2015 mean derived from an independent Δ14C record in the Los Angeles area, indicating that 2015 biospheric exchange was not highly anomalous. The presence of a large and seasonally varying biospheric signal even in the relatively dry climate of Los Angeles implies that atmospheric estimates of fossil fuel-CO2 emissions in other, potentially wetter, urban areas will be biased in the absence of reliable methods to separate fossil and biogenic CO2.

Attribution of Space-Time Variability in Global-Ocean Dissolved Inorganic Carbon.

The inventory and variability of oceanic dissolved inorganic carbon (DIC) is driven by the interplay of physical, chemical, and biological processes. Quantifying the spatiotemporal variability of these drivers is crucial for a mechanistic understanding of the ocean carbon sink and its future trajectory. Here, we use the Estimating the Circulation and Climate of the Ocean-Darwin ocean biogeochemistry state estimate to generate a global-ocean, data-constrained DIC budget and investigate how spatial and seasonal-to-interannual variability in three-dimensional circulation, air-sea CO2 flux, and biological processes have modulated the ocean sink for 1995-2018. Our results demonstrate substantial compensation between budget terms, resulting in distinct upper-ocean carbon regimes. For example, boundary current regions have strong contributions from vertical diffusion while equatorial regions exhibit compensation between upwelling and biological processes. When integrated across the full ocean depth, the 24-year DIC mass increase of 64 Pg C (2.7 Pg C year-1) primarily tracks the anthropogenic CO2 growth rate, with biological processes providing a small contribution of 2% (1.4 Pg C). In the upper 100 m, which stores roughly 13% (8.1 Pg C) of the global increase, we find that circulation provides the largest DIC gain (6.3 Pg C year-1) and biological processes are the largest loss (8.6 Pg C year-1). Interannual variability is dominated by vertical advection in equatorial regions, with the 1997-1998 El Niño-Southern Oscillation causing the largest year-to-year change in upper-ocean DIC (2.1 Pg C). Our results provide a novel, data-constrained framework for an improved mechanistic understanding of natural and anthropogenic perturbations to the ocean sink.

Quantifying Northern High Latitude Gross Primary Productivity (GPP) Using Carbonyl Sulfide (OCS).

The northern high latitude (NHL, 40°N to 90°N) is where the second peak region of gross primary productivity (GPP) other than the tropics. The summer NHL GPP is about 80% of the tropical peak, but both regions are still highly uncertain (Norton et al. 2019, https://doi.org/10.5194/bg-16-3069-2019). Carbonyl sulfide (OCS) provides an important proxy for photosynthetic carbon uptake. Here we optimize the OCS plant uptake fluxes across the NHL by fitting atmospheric concentration simulation with the GEOS-CHEM global transport model to the aircraft profiles acquired over Alaska during NASA's Carbon in Arctic Reservoirs Vulnerability Experiment (2012-2015). We use the empirical biome-specific linear relationship between OCS plant uptake flux and GPP to derive the six plant uptake OCS fluxes from different GPP data. Such GPP-based fluxes are used to drive the concentration simulations. We evaluate the simulations against the independent observations at two ground sites of Alaska. The optimized OCS fluxes suggest the NHL plant uptake OCS flux of -247 Gg S year-1, about 25% stronger than the ensemble mean of the six GPP-based OCS fluxes. GPP-based OCS fluxes systematically underestimate the peak growing season across the NHL, while a subset of models predict early start of season in Alaska, consistent with previous studies of net ecosystem exchange. The OCS optimized GPP of 34 PgC yr-1 for NHL is also about 25% more than the ensembles mean from six GPP data. Further work is needed to fully understand the environmental and biotic drivers and quantify their rate of photosynthetic carbon uptake in Arctic ecosystems.

The Impact of COVID-19 on CO2 Emissions in the Los Angeles and Washington DC/Baltimore Metropolitan Areas.

Responses to COVID-19 have resulted in unintended reductions of city-scale carbon dioxide (CO2) emissions. Here, we detect and estimate decreases in CO2 emissions in Los Angeles and Washington DC/Baltimore during March and April 2020. We present three lines of evidence using methods that have increasing model dependency, including an inverse model to estimate relative emissions changes in 2020 compared to 2018 and 2019. The March decrease (25%) in Washington DC/Baltimore is largely supported by a drop in natural gas consumption associated with a warm spring whereas the decrease in April (33%) correlates with changes in gasoline fuel sales. In contrast, only a fraction of the March (17%) and April (34%) reduction in Los Angeles is explained by traffic declines. Methods and measurements used herein highlight the advantages of atmospheric CO2 observations for providing timely insights into rapidly changing emissions patterns that can empower cities to course-correct CO2 reduction activities efficiently.

The Endometrioma Treatment Paradigm when Fertility Is Desired: A Systematic Review.

OBJECTIVE: To establish an endometrioma treatment paradigm (decision tree) in the treatment of an ovarian endometrioma through the review of current literature. DATA SOURCES: A thorough literature search, including PubMed, Google Scholar, and the Cochrane Library, was performed from April 2020 to July 2020. The review was completed by using the following keywords: METHODS OF STUDY SELECTION: Articles published in English that addressed the endometrioma in regard to the following were included: (1) diagnosis, (2) treatment of pain on the basis of size and/or surgical intervention, (3) treatment of fertility on the basis of size and/or surgical intervention, (4) surgical technique, (5) in vitro fertilization success on the basis of size and/or surgical intervention, (6) risk of rupture at the time of egg retrieval, (7) impact on the antimüllerian hormone and antral follicle count postsurgery, and (8) impact on implantation. TABULATION, INTEGRATION, AND RESULTS: Fifty-six articles were included in this systematic review. While conducting this literature review, several themes were noted. In general, the literature on the ovarian endometrioma seems to be homogeneous in regard to imaging the endometrioma, excision rather than desiccation for an endometrioma ≥3-cm causing pain and/or infertility, minimal use of bipolar energy at the time of ovarian surgery, and risk of severe infection secondary to inadvertent rupture of cysts during egg retrieval. Conversely, studies on the ovarian endometrioma are much more heterogeneous in terms of surgery and assisted reproductive technology, that is, whether surgery should be performed. Certainly, an endometrioma ≥5-cm should be excised before assisted reproductive technology. Moreover, it seems that the antral follicle count and implantation may be enhanced with surgery. CONCLUSION: By completing an extensive literature review, an easy-to-use algorithm for the diagnosis, evaluation, and treatment of endometriomas was developed to help clinicians in their treatment of patients with endometriosis in the short and long terms.

Laparoscopic Excision of Cesarean Scar Pregnancy with Scar Revision.

OBJECTIVE: To demonstrate our technique for robot-assisted laparoscopic ectopic pregnancy excision and concomitant scar revision. DESIGN: We present a stepwise narrated demonstration of our primary laparoscopic technique. SETTING: Although cesarean scar pregnancy is rare, it leads to life-threatening complications and often emergent hysterectomy [1,2]. Because of its rarity, there is a scarcity of centers with high-volume experience with its treatment, and no standardized diagnostic or management guidelines are yet available [3,4]. Recent evidence suggests that primary surgical management may be superior to medical or radiologic management as the latter methods carry a high reintervention rate [5]. An additional consideration in selecting a treatment method is a patient's plans for future fertility, as cesarean scar defects are associated with secondary infertility. Evidence shows that repair of cesarean scar defects decreases the likelihood of future recurrence and secondary infertility, thus it may be pertinent to select a management strategy that allows for the accomplishment of both ectopic pregnancy removal and defect revision. We present our primary laparoscopic approach to ectopic pregnancy excision and revision of the cesarean scar defect using techniques rooted in evidence and robust experience. INTERVENTIONS: Robot-assisted laparoscopic excision of a cesarean scar ectopic pregnancy with concomitant scar revision demonstrating key strategies to minimize blood loss and preserve future fertility. (1) A laparoscopic approach allows for concomitant ectopic pregnancy removal followed by cesarean scar revision. (2) Generous use of dilute vasopressin and purposeful application of electrosurgical energy provides hemostasis without the use of more invasive measures such as vascular clips or uterine artery balloons. (3) A multilayer closure is associated with a lower risk of wedge defect formation and uterine rupture. (4) Diagnostic hysteroscopy is a useful tool for identifying the location of the scar defect, assessing for an adequate repair, and identifying potential additional uterine pathology. CONCLUSION: Primary laparoscopic management is not only the most effective method with the lowest complication rates but is an approach that allows for simultaneous repair and revision of the cesarean scar defect. We demonstrate easily adaptable techniques for maintaining hemostasis, minimizing injury to normal myometrium, and creating multilayer closures that lead to successful revisions with minimal impact to subsequent fertility.

AAGL 2021 Endometriosis Classification: An Anatomy-based Surgical Complexity Score.

STUDY OBJECTIVE: To develop a new endometriosis classification system for scoring intraoperative surgical complexity and to examine its correlation with patient-reported pain and infertility. DESIGN: Multicenter study of patients treated at 3 recognized endometriosis centers. SETTING: Three specialized endometriosis surgical centers in São Paulo, Brazil and Barcelona, Spain. PATIENTS: Patients aged 15 to 45 years with histologically proven endometriosis and no history of pelvic malignancy underwent laparoscopic treatment of endometriosis. INTERVENTIONS: Demographic data and clinical history, including dysmenorrhea, noncyclic pelvic pain, dyspareunia, dysuria and dyschezia, were prospectively recorded. All patients were staged surgically according to the new 2021 American Association of Gynecologic Laparoscopists (AAGL) and revised American Society of Reproductive Medicine (ASRM) classification systems. The staging for each system was compared against a 4-level surgical complexity scale defined by the most complex procedure performed. MEASUREMENTS AND MAIN RESULTS: A total of 1224 patients undergoing surgery met inclusion criteria. The AAGL score discriminated between 4 stages of surgical complexity with high reproducibility (κ = 0.621), whereas the ASRM score discriminated between the complexity stages with poor reproducibility (κ = 0.317). The AAGL staging system correlated with dysmenorrhea, dyspareunia, dyschezia, total pain score, and infertility comparably with the ASRM staging system. CONCLUSION: The AAGL 2021 Endometriosis Classification allows for identifying objective intraoperative findings that reliably discriminate surgical complexity levels better than the ASRM staging system. The AAGL severity stage correlates comparably with pain and infertility symptoms with the ASRM stage.

Multiple Stable Isoprene-Ozone Complexes Reveal Complex Entrance Channel Dynamics in the Isoprene + Ozone Reaction.

Accurately characterizing isoprene ozonolysis continues to challenge atmospheric chemists. The reaction is believed to be a spontaneous, concerted cycloaddition. However, little information is available about the entrance channel and isoprene-ozone complexes thought to define the long-range portion of the reaction coordinate. Our coupled cluster and auxiliary field quantum Monte Carlo calculations predict multiple stable isoprene-ozone van der Waals complexes for trans-isoprene in the gas phase with moderate association energies. These results indicate that long-range dynamics in the isoprene-ozone entrance channel can impact the overall reaction in the troposphere and provide the spectroscopic information necessary to extend the microwave characterization of isoprene ozonolysis to prereactive complexes. At the air-water interface, Born-Oppenheimer molecular dynamics simulations indicate that the cycloaddition reaction between ozone and trans-isoprene follows a stepwise mechanism, which is quite distinct from our proposed gas-phase mechanism and occurs on a femtosecond time scale. The stepwise nature of isoprene ozonolysis on the aqueous surface is more consistent with the DeMore mechanism than with the Criegee mechanism suggested by the gas-phase calculations, suggesting that the reaction media may play an important role in the reaction. Overall, these predictions aim to provide a missing fundamental piece of molecular insight into isoprene ozonolysis, which has broad tropospheric implications due to its critical role as a nighttime source of hydroxyl radicals.

Increased Fetal Chromosome Detection with the Use of Operative Hysteroscopy During Evacuation of Products of Conception for Diagnosed Miscarriage.

STUDY OBJECTIVE: To determine whether incorporation of operative hysteroscopy with biopsy of products of conception, in conjunction with a suction curettage for a first trimester missed abortion, affected the rate of maternal cell contamination when chromosomal analysis was performed on the products of conception, and to determine the rates of retained products of conception with incorporation of hysteroscopy after suction curettage. DESIGN: Retrospective chart study. SETTING: Private, minimally invasive surgery and infertility practice with academic-community hospital affiliation. PATIENTS: Infertility patients undergoing evacuation of products of conception for documented first trimester miscarriages between 2006 and 2017. INTERVENTIONS: Suction curettage or hysteroscopic biopsy and suction curettage, followed by chromosomal analysis of products of conception for determination of fetal genetics. MEASUREMENTS AND RESULTS: A total of 264 charts were analyzed. Patients were categorized into 2 groups based on surgical collection of products of conception: group 1 (N = 174), suction curettage only, and group 2 (N = 90), a single procedure consisting of operative hysteroscopy with biopsy of products of conception followed by suction curettage and then diagnostic hysteroscopy to look for retained products. Data for chromosome detection and retained products of conception were available for 246 and 239 patients, respectively. No significant differences were detected between the groups for age, body mass index, ethnicity, gravida, parity, primary infertility, secondary infertility, spontaneous conception, single or multiple gestation, and surgical complications. Fetal chromosome detection was significantly higher without maternal contamination in group 2 (88.5%) compared with group 1 (64.8%) (p < .001). There was no significant between-group difference in postoperative retained products of conception. CONCLUSION: Obtaining fetal genetics can be useful when planning for a future successful pregnancy. The addition of operative hysteroscopy to biopsy the gestational sac, chorionic villi, and/or fetus significantly decreases the risk of maternal contamination and increases the ability to detect fetal chromosomes for genetic analysis without an increased risk of surgical complications. Despite the low risk of surgical complications, immediate second-look hysteroscopy after the completion of suction evacuation does not reduce the risk of postoperative retained products of conception.

Carbon dioxide sources from Alaska driven by increasing early winter respiration from Arctic tundra.

High-latitude ecosystems have the capacity to release large amounts of carbon dioxide (CO2) to the atmosphere in response to increasing temperatures, representing a potentially significant positive feedback within the climate system. Here, we combine aircraft and tower observations of atmospheric CO2 with remote sensing data and meteorological products to derive temporally and spatially resolved year-round CO2 fluxes across Alaska during 2012-2014. We find that tundra ecosystems were a net source of CO2 to the atmosphere annually, with especially high rates of respiration during early winter (October through December). Long-term records at Barrow, AK, suggest that CO2 emission rates from North Slope tundra have increased during the October through December period by 73% ± 11% since 1975, and are correlated with rising summer temperatures. Together, these results imply increasing early winter respiration and net annual emission of CO2 in Alaska, in response to climate warming. Our results provide evidence that the decadal-scale increase in the amplitude of the CO2 seasonal cycle may be linked with increasing biogenic emissions in the Arctic, following the growing season. Early winter respiration was not well simulated by the Earth System Models used to forecast future carbon fluxes in recent climate assessments. Therefore, these assessments may underestimate the carbon release from Arctic soils in response to a warming climate.

Detecting regional patterns of changing CO2 flux in Alaska.

With rapid changes in climate and the seasonal amplitude of carbon dioxide (CO2) in the Arctic, it is critical that we detect and quantify the underlying processes controlling the changing amplitude of CO2 to better predict carbon cycle feedbacks in the Arctic climate system. We use satellite and airborne observations of atmospheric CO2 with climatically forced CO2 flux simulations to assess the detectability of Alaskan carbon cycle signals as future warming evolves. We find that current satellite remote sensing technologies can detect changing uptake accurately during the growing season but lack sufficient cold season coverage and near-surface sensitivity to constrain annual carbon balance changes at regional scale. Airborne strategies that target regular vertical profile measurements within continental interiors are more sensitive to regional flux deeper into the cold season but currently lack sufficient spatial coverage throughout the entire cold season. Thus, the current CO2 observing network is unlikely to detect potentially large CO2 sources associated with deep permafrost thaw and cold season respiration expected over the next 50 y. Although continuity of current observations is vital, strategies and technologies focused on cold season measurements (active remote sensing, aircraft, and tall towers) and systematic sampling of vertical profiles across continental interiors over the full annual cycle are required to detect the onset of carbon release from thawing permafrost.

Cold season emissions dominate the Arctic tundra methane budget.

Arctic terrestrial ecosystems are major global sources of methane (CH4); hence, it is important to understand the seasonal and climatic controls on CH4 emissions from these systems. Here, we report year-round CH4 emissions from Alaskan Arctic tundra eddy flux sites and regional fluxes derived from aircraft data. We find that emissions during the cold season (September to May) account for ≥ 50% of the annual CH4 flux, with the highest emissions from noninundated upland tundra. A major fraction of cold season emissions occur during the "zero curtain" period, when subsurface soil temperatures are poised near 0 °C. The zero curtain may persist longer than the growing season, and CH4 emissions are enhanced when the duration is extended by a deep thawed layer as can occur with thick snow cover. Regional scale fluxes of CH4 derived from aircraft data demonstrate the large spatial extent of late season CH4 emissions. Scaled to the circumpolar Arctic, cold season fluxes from tundra total 12 ± 5 (95% confidence interval) Tg CH4 y(-1), ∼ 25% of global emissions from extratropical wetlands, or ∼ 6% of total global wetland methane emissions. The dominance of late-season emissions, sensitivity to soil environmental conditions, and importance of dry tundra are not currently simulated in most global climate models. Because Arctic warming disproportionally impacts the cold season, our results suggest that higher cold-season CH4 emissions will result from observed and predicted increases in snow thickness, active layer depth, and soil temperature, representing important positive feedbacks on climate warming.

Transcervical Radiofrequency Ablation of Symptomatic Uterine Fibroids: 2-Year Results of the SONATA Pivotal Trial.

Objective: To report 2-year results of sonography-guided transcervical fibroid ablation (TFA) using the Sonata® system in women with symptomatic uterine fibroids. Design: This is a prospective multicenter single-arm interventional trial. Methods: Premenopausal women with up to 10 clinically relevant uterine fibroids, each ranging from 1 to 5 cm in diameter, were treated with sonography-guided TFA on an outpatient basis and returned for regular follow-up visits for 2 years. Assessed outcomes included changes in symptom severity, heath-related quality of life, general health status, work and activity limitations, treatment satisfaction, adverse events, surgical reintervention, and occurrence of pregnancy and associated outcomes. Results: Among 147 enrolled women, 125 (85%) returned for follow-up at 2 years. Compared with baseline, symptom severity decreased from 55 ± 19 to 24 ± 18 (p < 0.001), health-related quality of life increased from 40 ± 21 to 83 ± 19 (p < 0.001), and EuroQol 5-Dimension scores increased from 0.72 ± 0.21 to 0.89 ± 0.14 (p < 0.001). Overall treatment satisfaction at 2 years was 94%. The mean percentage of missed work time, overall work impairment, and activity impairment significantly decreased at follow-up. Through 2 years, surgical reintervention for heavy menstrual bleeding was performed in 5.5% of patients. One singleton pregnancy occurred with a normal peripartum outcome. Conclusions: TFA treatment with the Sonata system provides significant clinical improvement through 2 years postablation, with a low incidence of surgical reintervention. Other favorable outcomes included a rapid return to work and substantial improvements in quality of life, symptom severity, work productivity, and activity levels.

Morcellation equipment: past, present, and future.

PURPOSE OF REVIEW: This review was written in an effort to describe the evolution of power morcellation equipment from their creation to their current state. In addition, this review addresses the continuously evolving equipment involved with power morcellation and looks to describe where the field is headed in the future. In addition, recent professional and federal recommendations have changed the way power morcellation is being approached and has led to the development of contained morcellation systems, which, although in their infancy, are also being proven to be well tolerated options. RECENT FINDINGS: This article will review the most current research on electronic power morcellation and the multiple attempts to prove superiority from the many different types of equipment, and also the many different approaches to morcellation. In addition, with the adaptation to contained morcellation, this review will cover research focused on optimizing a containment system and the techniques involved. SUMMARY: In summary, this review is aimed at describing many of the currently available power morcellation products and contained morcellation systems in an effort to allow physicians to understand the different options available, and to discuss well tolerated, effective, and clinically proven techniques that can lead to improved surgical outcomes in the future.

The minimally invasive approach to the symptomatic isthmocele - what does the literature say? A step-by-step primer on laparoscopic isthmocele - excision and repair.

PURPOSE OF REVIEW: The purpose of this review is to understand the minimally invasive approach to the excision and repair of an isthmocele. RECENT FINDINGS: Previous small trials and case reports have shown that the minimally invasive approach by hysteroscopy and/or laparoscopy can cure symptoms of a uterine isthmocele, including abnormal bleeding, pelvic pain and secondary infertility. A recent larger prospective study has been published that evaluates outcomes of minimally invasive isthmocele repair. Smaller studies and individual case reports echo the positive results of this larger trial. SUMMARY: The cesarean section scar defect, also known as an isthmocele, has become an important diagnosis for women who present with abnormal uterine bleeding, pelvic pain and secondary infertility. It is important for providers to be aware of the effective surgical treatment options for the symptomatic isthmocele. A minimally invasive approach, whether it be laparoscopic or hysteroscopic, has proven to be a safe and effective option in reducing symptoms and improving fertility. VIDEO ABSTRACT: http://links.lww.com/COOG/A37.