• Orthotopic Heart Transplant Recipient with Enteric-coated Mycophenolate Sodium (Myfortic) Induced Colitis

      Morris, Craig C; Stroud, Steven C; Golconda, Umamaheshwari; Gregoire, Sharon A; Juneman, Elizabeth B; Univ Arizona, Coll Med, Sarver Heart Ctr; Univ Arizona, Coll Med, Dept Pathol (INT SCIENTIFIC INFORMATION, INC, 2020-05-14)
      Objective: Rare disease Background: Mycophenolic acid is an immunosuppressive drug commonly used in solid organ transplantation to prevent acute and chronic allograft rejection. There are 2 common preparations of mycophenolic acid including mycophenolate mofetil (Cellcept), and enteric-coated mycophenolate sodium (Myfortic) which was developed to reduce the high rate of gastrointestinal side effects seen with Cellcept. Cases of mycophenolate mofetil induced colitis have been described in solid organ transplant patients and rarely in heart transplant patients, but enteric-coated mycophenolate sodium induced colitis is very rare and has not been reported in heart transplant patients. Case Report: A 66-year old male with an orthotopic heart transplant was admitted with diarrhea. The patient was on an immunosuppression regimen including mycophenolate mofetil for 10 weeks post-transplantation until complaining of soft stools and bloating. At this time, he was switched to enteric-coated mycophenolate sodium. At week 11 post-transplantation, the patient was admitted to the hospital with worsening diarrhea. Extensive workup was unrevealing. Colonoscopy with biopsy showed features of mycophenolic acid induced colitis. Enteric coated mycophenolate sodium was discontinued, and the patient's diarrhea markedly improved over the next 48 hours. The patient had no signs of colitis or solid organ rejection at 7-month follow up appointment. Conclusions: Although a diagnosis of exclusion, enteric-coated mycophenolate sodium induced colitis should be considered in the differential of an orthotopic heart transplant patient with diarrhea as discontinuing the medication can improve symptoms and avoid costly workups, however, patients should be monitored closely for signs of rebound rejection.
    • Distribution, status and conservation needs of the white-sided jackrabbit, Lepus callotis (Lagomorpha)

      Brown, David E.; Traphagen, Myles B.; Lorenzo, Consuelo; Gomez-Sapiens, Martha; Univ Arizona, Dept Geosci (INST BIOLOGIA, UNIV NACIONAL AUTONOMA MEXICO, 2018-03-13)
      Although an important game animal and a species of wide distribution, little is known about the natural history of the white-sided jackrabbit (Lepus callotis), its ecological requirements, and limiting factors. The information available suggests that this species may have undergone a reduction in both population numbers and distribution, and may be endangered due to habitat changes. The information presented herein should facilitate proposals for future research, and conservation and management actions.
    • Reinstatement of the Tamaulipas white-sided jackrabbit, Lepus altamirae, based on DNA sequence data

      Vargas, Karla; Brown, David; Wisely, Eldridge; Culver, Melanie; Univ Arizona, Sch Nat Resources & Environm; Univ Arizona, Genet Grad Interdisciplinary Program (INST BIOLOGIA, UNIV NACIONAL AUTONOMA MEXICO, 2019-05-27)
      In 1904, the Tamaulipas jackrabbit (Lepus altamirae) was described as a subspecies of Lepus merriami. In 1909, E. W. Nelson assigned L. altamirae to the white-sided group of jackrabbits, and in 1951, E. R. Hall reclassified it as a subspecies of black-tailed jackrabbits (Lepus californicus altamirae). Our comparison of the original 5 specimens of the Tamaulipas jackrabbit in the U.S. National Museum suggested this taxon had a close relationship to the white-sided jackrabbit, Lepus callotis. To validate Nelson's placement of the Tamaulipas jackrabbit within the white-sided group, we conducted phylogenetic analyses using the mitochondrial cytochrome b gene (MT-CYB). Our analyses of 2 specimens collected in 1898, suggest that L. altamirae is most closely related to Lepus flavigularis, a member of the white-sided group. Therefore, the Tamaulipas jackrabbit warrants taxonomic restoration as a species within the white-sided group of jackrabbits, which also includes L. callotis, L. flavigularis, and Lepus alleni.
    • The Extra Mile: Special Consideration of Atrial Fibrillation in Older Adults with Endurance Athletic History

      Maltagliati, Anthony J; Univ Arizona, Coll Med (INT SCIENTIFIC INFORMATION, INC, 2020-05-26)
      Objective: Challenging differential diagnosis Background: Aerobic exercise is uniformly accepted as one of the most important modifiable factors to improve cardiovascular health, but endurance athletic training poses a significant risk factor for development of atrial fibrillation (AFib) in middle-aged and older adults. Ubiquitous risk assessment tools (CHADS2 and CHA2DS2-VASc) and US Preventive Services Task Force guidelines do not presently account for this association. A case is presented which illustrates a dire outcome of undiagnosed AFib in an elderly male patient who had run many marathons. Case Report: An 80-year-old male with well-controlled hypertension and hypercholesterolemia and a history significant for running many marathons throughout his life was brought in via ambulance after being found down with head trauma by his wife at home. A short run of AFib was recorded on telemetry and electrocardiogram (ECG) and a review of previous ECGs revealed evidence of interatrial block (Bayes Syndrome), though the patient had no history of AFib or anticoagulation. This coupled with imaging indicated thromboembolic stroke to the left middle cerebral artery leading to right-sided hemiplegia and a subsequent fall to the right, causing right-sided head trauma and intracranial hemorrhage. His clinical course did not improve, and on his fifth day of admission he was transferred to comfort care, extubated, and succumbed to his injuries. Conclusions: This case and the accompanying summary of evidence strongly encourage further investigation and a higher index of suspicion for AFib in asymptomatic older adults with a history of endurance athletic training.
    • Integrating Touchscreen-Based Geriatric Assessment and Frailty Screening for Adults With Multiple Myeloma to Drive Personalized Treatment Decisions

      Nathwani, Nitya; Kurtin, Sandra E; Lipe, Brea; Mohile, Supriya Gupta; Catamero, Donna D; Wujcik, Debra; Birchard, Kristy; Davis, Agnes; Dudley, William; Tompkins Stricker, Carrie; et al. (AMER SOC CLINICAL ONCOLOGY, 2019-11-25)
      Patients were white (72%; n = 86), mean age was 72 years (range, 65-85 years), and averaged 7.71 minutes (range, 2-17 minutes) for survey completion. Providers averaged 3.2 minutes (range, 1-10 minutes) to review mGA results. Using International Myeloma Working Group frailty score, patients were fit (39%; n = 64), intermediate fit (33%; n = 55), or frail (28%; n = 46). Providers selected more aggressive treatments in 16.3% of patients and decreased treatment intensity in 34% of patients; treatment intensification was more common for fit patients and milder treatments for frail patients (χ2 = 20.02; P < .0001). Transplant eligibility significantly correlated with fit status and transplant ineligibility with frail status (P = .004). Outcomes on 144 patients 3 months post study visit showed 19.4% (n = 28) had grade ≥ 3 hematologic toxicities, 38.9% (n = 56) had dose modifications, and 18% (n = 26) had early therapy cessation.
    • Before Consent: Qualitative Analysis of Deliberations of Patients With Advanced Cancer About Early-Phase Clinical Trials

      Garrett, Sarah B; Matthews, Thea M; Abramson, Corey M; Koenig, Christopher J; Hlubocky, Fay J; Daugherty, Christopher K; Munster, Pamela N; Dohan, Daniel; Univ Arizona (AMER SOC CLINICAL ONCOLOGY, 2019-10-11)
      PURPOSE: Patients with advanced cancer and oncologists deliberate about early-phase (EP) trials as they consider whether to pursue EP trial enrollment. We have limited information about those deliberations and how they may facilitate or impede trial initiation. This study describes these deliberations and their relationship to trial initiation. PATIENTS AND METHODS: We collected longitudinal, ethnographic data on deliberations of patients with advanced cancer at two academic medical centers. We used constant comparative and framework analyses to characterize the deliberative process and its relationship to trial initiation. RESULTS: Of 96 patients with advanced cancer, 26% initiated EP enrollment and 19% joined a trial. Constant comparative analysis revealed two foci of deliberation. Setting the stage focused on patient and physician support for EP trial involvement, including patients? interest in research and oncologists? awareness of trials and assessment of patient fit. Securing a seat focused on eligibility for and entrance to a specific trial and involved trial availability, treatment history, disease progression, and enrollment timing. Patients enrolled in a trial only when both stages could be successfully navigated. CONCLUSION: Ethnographic data revealed two foci of deliberation about EP trial enrollment among patients with advanced cancer. Physician support played a consequential role in both stages, but enrollment also reflected factors beyond the control of any specific individual. Insights from this study, combined with other recent studies of trial enrollment, advance our understanding of the complex process of EP trial accrual and may help identify strategies to improve rates of participation.
    • A Mathematical Model for the Release, Transport, and Retention of Per‐ and Polyfluoroalkyl Substances (PFAS) in the Vadose Zone

      Guo, Bo; Zeng, Jicai; Brusseau, Mark L.; Univ Arizona, Dept Hydrol & Atmospher Sci; Univ Arizona, Dept Environm Sci (AMER GEOPHYSICAL UNION, 2020-01-10)
      Per- and polyfluoroalkyl substances (PFAS) are emerging contaminants of critical concern. As surfactants, PFAS tend to accumulate at air-water interfaces and may stay in the vadose zone for long times before contaminating groundwater. Yet not well understood, the extent of retention in the vadose zone has critical implications for risk management and remediation strategies. We present the first mathematical model that accounts for surfactant-induced flow and solid-phase and air-water interfacial adsorption. We apply the model to simulate PFOS (a PFAS compound of primary concern) transport in the vadose zone at a model fire-training area site impacted by aqueous film-forming foam (AFFF). Air-water interfacial adsorption is shown to have a significant impact-amplified by the low water content due to gravity drainage-total retardation factors range from 233 to 1,355 for the sand and 146 to 792 for the soil used in the study. The simulations illustrate it can take several decades or longer for PFOS to reach groundwater. Counterintuitively, the lower water content in the sand-due to stronger drainage and weaker capillary retention-leads to retardation factors greater than for the soil. Also, most PFOS is adsorbed at air-water interfaces with only 1-2% in the aqueous phase. The implications include (1) fine-texture materials could have lower retardation factors than sand due to higher retained water content, (2) soil PFAS concentrations are likely to be orders of magnitude higher than those in groundwater at source zones. Both implications are consistent with recent field observations at hundreds of AFFF-impacted sites.
    • Subsolar Electron Temperatures in the Lower Martian Ionosphere

      Peterson, W.K.; Andersson, L.; Ergun, R.; Thiemann, Ed; Pilinski, Marcin; Thaller, S.; Fowler, C.; Mitchell, D.; Benna, M.; Yelle, R., V; et al. (AMER GEOPHYSICAL UNION, 2020-02-13)
      Martian subsolar electron temperatures obtained below 250 km are examined using data obtained by instruments on the Mars Atmosphere Evolution Mission (MAVEN) during the three subsolar deep dip campaigns and a one-dimensional fluid model. This analysis was done because of the uncertainty in MAVEN low electron temperature observations at low altitudes and the fact that the Level 2 temperatures reported from the MAVEN Langmuir Probe and Waves instrument are more than 400 K above the neutral temperatures at the lowest altitudes sampled (similar to 120 km). These electron temperatures are well above those expected before MAVEN was launched. We find that an empirical normalization parameter, neutral pressure divided by local electron heating rate, organized the electron temperature data and identified a similar altitude (similar to 160 km) and time scale (similar to 2,000 s) for all three deep dips. We show that MAVEN data are not consistent with a plasma characterized by electrons in thermal equilibrium with the neutral population above 100 km. Because of the lack data below 120 km and the uncertainties of the data and the cross sections used in the one-dimensional fluid model above 120 km, we cannot use MAVEN observations to prove that the electron temperature converges to the neutral temperature below 100 km. However, the uncertainty of the electron temperature altitude profile below 120 km does not impact our understanding of the role of electron temperature in determining ion escape rates because ion escape is determined by electron temperatures above 180 km.
    • Structural Control on Megathrust Rupture and Slip Behavior: Insights From the 2016 Mw 7.8 Pedernales Ecuador Earthquake

      Soto‐Cordero, Lillian; Meltzer, Anne; Bergman, Eric; Hoskins, Mariah; Stachnik, Joshua C.; Agurto‐Detzel, Hans; Alvarado, Alexandra; Beck, Susan; Charvis, Philippe; Font, Yvonne; et al. (AMER GEOPHYSICAL UNION, 2020-02-17)
      The heterogeneous seafloor topography of the Nazca Plate as it enters the Ecuador subduction zone provides an opportunity to document the influence of seafloor roughness on slip behavior and megathrust rupture. The 2016 M-w 7.8 Pedernales Ecuador earthquake was followed by a rich and active postseismic sequence. An internationally coordinated rapid response effort installed a temporary seismic network to densify coastal stations of the permanent Ecuadorian national seismic network. A combination of 82 onshore short and intermediate period and broadband seismic stations and six ocean bottom seismometers recorded the postseismic Pedernales sequence for over a year after the mainshock. A robust earthquake catalog combined with calibrated relocations for a subset of magnitude >= 4 earthquakes shows pronounced spatial and temporal clustering. A range of slip behavior accommodates postseismic deformation including earthquakes, slow slip events, and earthquake swarms. Models of plate coupling and the consistency of earthquake clustering and slip behavior through multiple seismic cycles reveal a segmented subduction zone primarily controlled by subducted seafloor topography, accreted terranes, and inherited structure. The 2016 Pedernales mainshock triggered moderate to strong earthquakes (5 <= M <= 7) and earthquake swarms north of the mainshock rupture close to the epicenter of the 1906 M-w 8.8 earthquake and in the segment of the subduction zone that ruptured in 1958 in a M-w 7.7 earthquake.
    • On the Robustness of Conceptual Rainfall‐Runoff Models to Calibration and Evaluation Data Set Splits Selection: A Large Sample Investigation

      Guo, Danlu; Zheng, Feifei; Gupta, Hoshin; Maier, Holger R.; Univ Arizona, Dept Hydrol & Atmospher Sci (AMER GEOPHYSICAL UNION, 2020-02-25)
      Conceptual rainfall-runoff (CRR) models are widely used for runoff simulation and for prediction under a changing climate. The models are often calibrated with only a portion of all available data at a location and then evaluated independently with another part of the data for reliability assessment. Previous studies report a persistent decrease in CRR model performance when applying the calibrated model to the evaluation data. However, there remains a lack of comprehensive understanding about the nature of this "low transferability" problem and why it occurs. In this study we employ a large sample approach to investigate the robustness of CRR models across calibration/validation data splits. Specially, we investigate (1) how robust is CRR model performance across calibration/evaluation data splits, at catchments with a wide range of hydroclimatic conditions; and (2) is the robustness of model performance somehow related to the hydroclimatic characteristics of a catchment? We apply three widely used CRR models, GR4J, AWBM and IHACRE_CMD, to 163 Australian catchments having long-term historical data. Each model was calibrated and evaluated at each catchment, using a large number of data splits, resulting in a total of 929,160 calibrated models. Results show that (1) model performance generally exhibits poor robustness across calibration/evaluation data splits and (2) lower model robustness is correlated with specific catchment characteristics, such as higher runoff skewness and aridity, highly variable baseflow contribution, and lower rainfall-runoff ratio. These results provide a valuable benchmark for future model robustness assessments and useful guidance for model calibration and evaluation.
    • Vertical Displacements of the Amazon Basin From GRACE and GPS

      Knowles, L. A.; Bennett, R. A.; Harig, C.; Univ Arizona, Dept Geosci (AMER GEOPHYSICAL UNION, 2020-02-10)
      The extent to which Gravity Recovery and Climate Experiment (GRACE)-recovered gravity anomalies can improve our understanding of Global Positioning System (GPS)-measured vertical displacements is currently uncertain. To address this issue, we compared vertical displacements measured by 23 GPS stations in the Amazon basin with displacements estimated from GRACE geopotential fields. We show that despite poor correlation (r(2) = 0.15) between rate estimates in GPS and GRACE-derived displacement time series, further analyses reveal low bias between annual amplitude estimates and a scaling near 1. There is higher correlation (r(2) = 0.78) between annual periodic motions, with near 1 to 1 agreement, but there is poor correlation (r(2) = 0.02) and little agreement between semiannual amplitude estimates. Subtracting GRACE displacements from the GPS time series flattens the GPS power spectra, reducing the spectral index magnitude, on average, from -1.2759 +/- 0.0007 ("fractional Brownian motion") to 0.3346 +/- 0.0006 ("fractional Gaussian noise"), suggesting that some fraction of the apparent GPS error correlation derives from mass loading signals that are not completely characterized by secular trends or seasonal periodic motions. From March 2011 to November 2016, we find a GPS and GRACE-derived displacement combined average uplift of the Amazon basin of 1.20 +/- 0.26 mm/yr and combined average annual periodic motion of 10.22 +/- 0.57 mm. Deviations from a standard trajectory model for site motion are apparent in both data sets and appear to coincide with various flooding and drought events between 2011 and 2016, which suggests that the GPS coordinate time series record displacements driven by large-scale climate oscillations.
    • Marine Heatwaves in China's Marginal Seas and Adjacent Offshore Waters: Past, Present, and Future

      Yao, Yulong; Wang, Junjie; Yin, Jianjun; Zou, Xinqing; Univ Arizona, Dept Geosci (AMER GEOPHYSICAL UNION, 2020-02-21)
      Under the combined impacts of natural changes and human activities, the past, current, and future marine heatwaves (MHWs) in China's marginal seas and adjacent offshore waters (CMSOW) need a comprehensive understanding. This study provides a systematic analysis of the spatiotemporal variations using daily sea surface temperature data and simulates the future trend using 12 climate models. During 1982–2018, the mean annual total days, duration, frequency, and mean intensity of the MHWs in the CMSOW increased by 20–30 days/decade, 5–9 days/decade, 1–2 decade−1, and 0.1–0.3°C/decade, respectively (p <0.01). The maximum sea surface temperature anomalies in the Bohai Sea was over 6–8°C, and the MHW's frequency, duration, and mean intensity were higher than twice the global average, which could have impacted fishery resources and occurrence of harmful algal blooms. The variations of the MHWs in the CMSOW result from the robust ocean surface warming, which is caused by increased solar radiation due to reduced cloud cover, reduced ocean heat loss from weaker wind speed, weakening but warmer Kuroshio, and strong El Niño. In the future, the areas with longer total days and duration will increase; the spatial pattern of frequency has a negative relationship with that of duration while that of mean intensity is mostly unchanged. Year 2040 is a key node for the future changes of MHW under different Representative Concentration Pathways. The trend of total days increases from fast to slow, and frequency shows an opposite trend; the duration and mean intensity rise faster after 2040.
    • On the Reliability of Variable‐Rate Pumping Test Results: Sensitivity to Information Content of the Recorded Data

      Naderi, Mostafa; Gupta, Hoshin V.; Univ Arizona, Dept Hydrol & Atmospher Sci (AMER GEOPHYSICAL UNION, 2020-04-08)
      Pumping tests are widely used to estimate parameters such as transmissivity and storativity, using aquifer response equations that assume a time-constant pumping rate. However, in actual practice the discharge rate will often vary erratically and follow a generally decreasing trend as the test proceeds. In such cases, if the discharge history is recorded with sufficient temporal fidelity, accurate solutions can be obtained via time domain piecewise-linear numerical integration. However, if the discharge data do not adequately characterize the variability in the dynamics of the pumping rate, the result can be information loss leading to bias in the inferred parameter estimates. Here, we investigate the severity of this problem for six selected aquifer types, including those that are confined, leaky, and unconfined. Our results indicate that the effects of information loss due to inadequate temporal resolution of the discharge data and systematic observational error are significantly more severe than due to random observational error. The implication is that operators should make a concerted effort to record the pumping rate at the highest practical temporal resolution throughout the duration of the test.
    • Local Source Vp and Vs Tomography in the Mount St. Helens Region With the iMUSH Broadband Array

      Ulberg, Carl W.; Creager, Kenneth C.; Moran, Seth C.; Abers, Geoffrey A.; Thelen, Weston A.; Levander, Alan; Kiser, Eric; Schmandt, Brandon; Hansen, Steven M.; Crosson, Robert S.; et al. (AMER GEOPHYSICAL UNION, 2020-02-19)
      We present new 3-D P wave and S wave velocity models of the upper 20 km of the Mount St. Helens (MSH) region. These were obtained using local-source arrival time tomography from earthquakes and explosions recorded at 70 broadband stations deployed as part of the imaging Magma Under St. Helens (iMUSH) project and augmented by several data sets. Principal features of our models include (1) low P wave and S wave velocities along the St. Helens seismic zone to depths of at least 20 km corresponding to high conductivity imaged by iMUSH magnetotelluric studies. This delineates a zone of weakness that magma can exploit at the location of MSH; (2) a 5- to 7-km diameter, 6-15 km deep, 3-6% negative P wave and S wave velocity anomaly beneath MSH, consistent with previous estimates of the source region for recent eruptions. We interpret this as a magma storage region containing up to 15-20 km(3) of partial melt, which is about 5 times more than the largest documented eruption at MSH; (3) a broad region of low P wave velocity below 10-km depth extending between Mount Adams and Mount Rainier along and to the east of the main Cascade arc, which is likely due to high-temperature arc crust and possible presence of fluids or melt; (4) several anomalies associated with surface-mapped features, including high-velocity igneous units such as the Spud Mountain and Spirit Lake plutons and low velocities in the Chehalis sedimentary basin and the Indian Heaven volcanic field. Our results place further constraints on the geometry of these features at depth. Plain Language Summary We deployed 70 seismometers around Mount St. Helens volcano from 2014 to 2016, which measured the surface ground motion from hundreds of small earthquakes, as well as from 23 explosions that were set off in 2014. We recorded the onset time of shaking from these sources and used a specialized computer code to model how quickly seismic waves travel through the subsurface. Seismic wave speed can be influenced by several factors, including rock type, presence of magma/fluids, temperature, pressure, and how fractured the rock is. Based on the seismic wave speeds in our model, we make several geological interpretations, including (1) increased fluids or fractures, or presence of sedimentary rocks corresponding to elevated earthquake activity to the NNW of Mount St. Helens; (2) a magma storage region beneath the volcano similar to results from previous studies. Our model places further constraints on the orientation and size of the region; (3) a large zone of high temperatures and possible fluids or magma related to regional volcanism between and to the east of Mount Adams and Mount Rainier; (4) more detailed size and depth constraints on geological features seen at the surface, including sedimentary basins and rock units related to previous regional volcanism. Key Points New high-resolution P wave and S wave velocity models are calculated for the Mount St. Helens region Velocity models place further constraints on size and location of magma storage regions, seismic zones, sedimentary basins, and plutons These shed light on the accretionary history of the Siletzia terrane, with a transitional upper crustal boundary near Mount St. Helens
    • A Multicentury Perspective on the Relative Influence of Seasonal Precipitation on Streamflow in the Missouri River Headwaters

      Frederick, S. E.; Woodhouse, C. A.; Univ Arizona, Sch Geog & Dev; Univ Arizona, Lab Tree Ring Res (AMER GEOPHYSICAL UNION, 2020-04-21)
      The impacts of warming temperatures and declining snowpack on seasonal water yields in the Missouri River Headwaters are not well understood, revealing a gap in our understanding of regional hydroclimate and drivers of streamflow within the Upper Missouri River basin. This study presents the first annually resolved tree-ring reconstruction of spring precipitation for the Missouri River Headwaters. This reconstruction along with existing tree-ring reconstructions of 1 April snow water equivalence (SWE) and water year streamflow are used to detect variable influences of winter and spring precipitation on streamflow over past centuries, and relative to the modern period. The results suggest that spring precipitation has been a more consistent influence on water year streamflow in the Missouri River Headwaters over past centuries than winter snowpack. The strong relationship between 1 April SWE values and water year streamflow in the Missouri River Headwaters observed over much of the 20th century is not found to be a consistent feature of these multicentury paleorecords. Instead, the climatic influences on streamflow within the Missouri River Headwaters are likely more variable than 20th-century instrumental records indicate.
    • Local Economic Conditions and Fertility from the Great Depression through the Great Recession

      Schaller, Jessamyn; Fishback, Price; Marquardt, Kelli; Univ Arizona, Dept Econ (AMER ECONOMIC ASSOC, 2020-05-01)
    • Randomized Double-Blind Phase II Study of Maintenance Pembrolizumab Versus Placebo After First-Line Chemotherapy in Patients With Metastatic Urothelial Cancer

      Galsky, Matthew D; Mortazavi, Amir; Milowsky, Matthew I; George, Saby; Gupta, Sumati; Fleming, Mark T; Dang, Long H; Geynisman, Daniel M; Walling, Radhika; Alter, Robert S; et al. (AMER SOC CLINICAL ONCOLOGY, 2020-04-09)
      Between December 2015 and November 2018, 108 patients were randomly assigned to pembrolizumab (n = 55) or placebo (n = 53). The objective response rate was 23% with pembrolizumab and 10% with placebo. Treatment-emergent grade 3-4 adverse events occurred in 59% receiving pembrolizumab and 38% of patients receiving placebo. Progression-free survival was significantly longer with maintenance pembrolizumab versus placebo (5.4 months [95% CI, 3.1 to 7.3 months] v 3.0 months [95% CI; 2.7 to 5.5 months]; hazard ratio, 0.65; log-rank P = .04; maximum efficiency robust test P = .039). Median overall survival was 22 months (95% CI, 12.9 months to not reached) with pembrolizumab and 18.7 months (95% CI, 11.4 months to not reached) with placebo. There was no significant interaction between PD-L1 CPS ≥ 10 and treatment arm for progression-free survival or overall survival.
    • Temporal‐Geochemical Evolution of the Persani Volcanic Field, Eastern Transylvanian Basin (Romania): Implications for Slab Rollback Beneath the SE Carpathians

      Ducea, Mihai N.; Barla, Anca; Stoica, Adriana M.; Panaiotu, Cristian; Petrescu, Lucian; Univ Arizona, Dept Geosci (AMER GEOPHYSICAL UNION, 2020-04-16)
      The Quaternary Persani volcanic field (PVF) consists of alkali basalts formed in an extensional basin at the SE end of the Transylvanian basin, near an important anomaly in the European mantle, the Vrancea slab, a seismically active near-vertical lithospheric fragment of debated origin. The PVF is the only basaltic field regionally, has been studied geochemically in the past, and is also known for the presence of abundant mantle xenoliths. Here, we describe new geochemical data on rocks recently dated by Ar-Ar chronometry and show that while we can reproduce virtually all previous results, there is a clear temporal evolution of the magmatic system. There is an increase of over 80 degrees C in temperatures determined by the Si activity thermometer, from 1,300 degrees C to 1,380 degrees C during the similar to 0.5-Myr duration of volcanic activity, which is accompanied by several coherent trends in geochemistry, among which the decrease of Zn/Fe and Sr-87/Sr-86 ratios over time. Earlier, higher Zn/Fe ratios are indicative of a pyroxenite/eclogite-dominated source, which gradually changed to a peridotite-dominated source. These characteristics are typical of a dynamic mantle in which vertical mantle lithosphere tectonics, either due to slab rollback or mantle dripping plays a role and are not consistent with simple decompression melting of asthenosphere. Synchronous adakitic rocks found about 25-30 km east of PVF are presumed to be slab melts and are consistent with the Vrancea slab rollback as the trigger for mantle melting responsible for the PVF.
    • Overdamped dynamics of a Brownian particle levitated in a Paul trap

      Conangla, Gerard P.; Nwaigwe, Dwight; Wehr, Jan; Rica, Raúl A.; Univ Arizona, Program Appl Math; Univ Arizona, Dept Math (AMER PHYSICAL SOC, 2020-05-11)
      We study the dynamics of the center of mass of a Brownian particle levitated in a Paul trap. We mostly focus on the overdamped regime in the context of levitodynamics, comparing theory with numerical simulations and experimental data from our Paul trap. We provide an exact analytical solution to the stochastic equation of motion, expressions for the standard deviation of the motion, and thermalization times by using the WKB method under two different limits. Finally, we prove that the power spectral density of the motion can be approximated by that of an Ornstein-Uhlenbeck process and use the found expression to calibrate the motion of a trapped particle.
    • Snowpack‐ and Soil Water Content‐Related Hydrologic Indices and Their Association With Radial Growth of Conifers in the Sierra Nevada, California

      Shamir, Eylon; Meko, Dave; Touchan, Ramzi; Lepley, Kai S.; Campbell, Rochelle; Kaliff, Rebecca N.; Georgakakos, Konstantine P.; Univ Arizona, Lab Tree Ring Res (AMER GEOPHYSICAL UNION, 2020-12-18)
      The utility of a high-resolution snow-hydrologic model to derive climatological indices that describe the variability in radial growth of four conifer species in two Sierra Nevada sites is presented herein. Nine annual indices associated with radial growth were developed to represent the winter dormancy, characteristics of the snowpack and soil water content, and the duration of the seasons. Site chronologies of earlywood (EW) and latewood (LW) ring widths were developed for mountain hemlock (Tsuga mertensiana), red fir (Abies magnifica), white fir (Abies concolor), and ponderosa pine (Pinus ponderosa) at two sites on leeward and windward slopes. The signal strength for annual climatological indices derived from model output was tested with correlation and regression, in combination with principal components analysis. Results show significant snow-related climate signal in the tree-ring data, with substantial differences between species and between EW and LW. Dependence on previous year's snow and soil moisture (a lagged response) were found for EW of hemlock and red fir. The primary EW-LW signal contrast for those species is a shift toward dependence on current-year moisture conditions for LW, especially for red fir. Lagged climate response was less evident for white fir and ponderosa pine. Regression of tree-ring series on principal components of climatological indices showed a stronger average signal in EW (R-2 = 0.48) than in LW (R-2 = 0.35). Differences in tree-ring hydrologic signal at the two sites are attributed to microclimate and contrasts in snow regime. Results attest to the hydrologic model usefulness for investigating temporal relationships between tree rings and local climate.