bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sonographically Based Diagnosis of Contralateral Malignancy in Preoperative Patients With Papillary Thyroid Microcarcinoma
Authors: Kim Dong Wook , Park Ha Kyoung , Ha Tae Kwun , Kim Sang Hyo , Jung Soo Jin , Kim Do Hun , Bae Sang Kyun 
Published: April 2015

ObjectivesWe aimed to assess the usefulness of sonographically based diagnosis to predict whether contralaterally located dominant thyroid nodules are malignant or benign in patients with known papillary thyroid microcarcinoma.MethodsWe studied 143 patients with primary papillary thyroid microcarcinoma who underwent preoperative thyroid sonography. Each dominant thyroid nodule was prospectively classified into 1 of 5 diagnostic categories by a single radiologist: benign, probably benign, borderline, possibly malignant, and malignant. We calculated the efficacy of sonographic diagnosis for contralateral malignancy by using histopathologic or long‐term sonographic follow‐up results as reference standards.ResultsOf the 143 primary papillary thyroid microcarcinomas, 17 showed satellite carcinomas; hence, the bilaterality rate in all patients was 11.9% (17 of 143). Real‐time sonography of the contralateral thyroid yielded no thyroid nodules (n = 55) and benign (n = 52), probably benign (n = 10), borderline (n = 13), possibly malignant (n = 4), and malignant (n = 9) nodules. When the borderline sonographic class was excluded, the sensitivity, specificity, positive and negative predictive values, and accuracy of sonographic diagnosis for detecting contralateral malignancy were 86.7%, 100%, 100%, 98.3%, and 98.5%, respectively. Within individual sonographic classes for the dominant thyroid nodules, the diagnostic accuracy rates for classes IV and V (possibly malignant and malignant) were higher than those for other classes.ConclusionsSonographically based diagnosis may be helpful for detection of contralateral malignancy in preoperative patients with papillary thyroid microcarcinoma.
Implementation and Assessment of a Curriculum for Bedside Ultrasound Training
Authors: Turner Elizabeth E. , Fox J. Christian , Rosen Mark , Allen Angela , Rosen Sasha , Anderson Craig 
Published: April 2015

ObjectivesThis study assessed a curriculum for bedside ultrasound (US) and compared outcomes from 2 common training pathways.MethodsThe program consisted of e‐learning paired with expert‐led hands‐on training administered to pulmonary/critical care and cardiology fellows with no prior formal training in bedside US. This “simulation‐based learner” group completed a survey of attitudes and confidence before and after training, and knowledge and skills were assessed after training. The surveys and scores of the simulation‐based learners were compared to the scores of “experts,” who were US‐trained emergency physicians, and “apprentice learners,” who were intensivist physicians informally trained in bedside US on the job during fellowships.ResultsThere was a significant difference in the self‐reported level of prior training between the groups (simulation‐based learners, 2.8; apprentice learners, 3.7; experts, 4.1, on a scale of 1–5 [P= .02]) but no difference in the interest level or perceived importance of bedside US. The study curriculum was successful, as shown by scores that exceeded the comparison groups in the cardiac and pulmonary courses (cardiac: simulation‐based learners, 80%; apprentice learners, 73%; experts, 62% [P= .001]; pulmonary: 84%, 75%, and 72%, respectively [P =.02]). The simulation‐based learners gained confidence in skills, whereas the comparison groups lost confidence after testing (P < .005); however, the simulation‐based learners gained confidence in US subject areas that were not taught (abdomen [P <.002] and miscellaneous [P =.005]).ConclusionsThe simulation‐based learner curriculum resulted in comparable or greater knowledge and confidence in each area of US versus the comparison groups. Findings of overgeneralization of confidence highlight the importance of quality assurance and supervision in bedside US training programs.
Impact of Accreditation Training for Residents on Sonographic Quality in Gynecologic Emergencies
Authors: Popowski Thomas , Huchon Cyrille , Fathallah Khadija , Falissard Bruno , Dumont Alexandre , Fauconnier Arnaud 
Published: April 2015

ObjectivesTo assess the impact of an educational intervention based on an original accreditation training program on the quality of emergency sonography performed by obstetrics and gynecology (Ob/Gyn) residents.MethodsWe conducted a prospective before‐after study on residents who performed bedside standardized sonographic examinations as first‐line investigations in patients seen at our gynecologic emergency department. In both periods, the residents followed a 1‐hour class taught by a board‐certified Ob/Gyn sonography expert (opinion leader) and received a written standardized imaging protocol. An accreditation training process was implemented for the new residents at the beginning of the second period: 5 complete sonographic examinations were required for each resident, and facilitated feedback from the opinion leader was performed using a dedicated sonographic quality score. During both periods, all consecutive sonograms were collected and stored. The primary outcome was the sonographic quality score. A mixed model for repeated measures was used to compare scores in both periods from 20 consecutive sonographic examinations performed by 5 residents who were different in each period.ResultsThe mixed model analysis showed an increase in quality scores in the post–accreditation training compared to the pre–accreditation training period (estimated coefficient ± SD, 4.13 ± 0.51; t = 8.16). The sonographic examination order also had a significant effect in both periods (estimated coefficient ± SD, 0.11 ± 0.03; t = 3.99).ConclusionsAn accreditation training process including facilitated feedback from a local opinion leader improved the quality of sonographic examinations performed by Ob/Gyn residents in women presenting to a gynecologic emergency department.
Abnormal Umbilical Artery Doppler Findings in the Recipient Twin Before Laser Surgery for Twin‐Twin Transfusion Syndrome
Authors: Patel Shivani , Quintero Rubén A. , Kontopoulos Eftichia V. , Korst Lisa M. , Llanes Arlyn , Chmait Ramen H. 
Published: April 2015

ObjectivesIn twin‐twin transfusion syndrome (TTTS), persistent absent or reversed end‐diastolic flow in the umbilical artery is a rare finding in the recipient twin, and the clinical implications of this finding are not well characterized. We sought to study the clinical importance of abnormal umbilical artery Doppler waveforms in recipient twins and determine the perinatal survival of these twins after laser surgery.MethodsA retrospective study of patients with TTTS treated with laser surgery between 2006 and 2012 was conducted. Recipient twins with absent or reversed umbilical artery end‐diastolic flow on preoperative sonography were identified, and clinical and perinatal outcomes were compared to the remaining cohort. Statistical analyses were performed with Fisher exact and χ2 tests.ResultsOf 369 consecutive TTTS cases, 14 (3.8%) had absent or reversed umbilical artery end‐diastolic flow in the recipient twin. The rate of hydrops was higher in this group compared to those without absent or reversed flow (35.7% [5 of 14] versus 10.1% [36 of 355]; P = .0125). The rate of recipient twin growth restriction was also higher in the absent or reversed flow group (28.6% [4 of 14] versus 3.9% [14 of 355]; P = .0029). There was an increased rate of recipient fetal demise within 24 hours after surgery in those with absent or reversed flow (21.4% [3 of 14] versus 2.5% [9 of 355]; P = .0078), although there was no statistical difference in 30‐day survival between the groups (78.6% [11 of 14] versus 89.9% [319 of 355]; P = .1751).ConclusionsDoppler findings of absent or reversed umbilical artery end‐diastolic flow are rare in recipient twins. Although immediate post–laser surgery survival is relatively decreased in this group, overall perinatal survival rates appear to be favorable.
Fetal Thymus Volume Estimation by Virtual Organ Computer‐Aided Analysis in Normal Pregnancies
Authors: Re Claudia , Bertucci Emma , Weissmann-Brenner Alina , Achiron Reuven , Mazza Vincenzo , Gindes Liat 
Published: April 2015

ObjectivesThe thymus has a pyramidal shape, which is best shown in coronal planes. The aim of this study was to evaluate the potential of virtual organ computer‐aided analysis to estimate fetal thymus volume in normal pregnancies.MethodsThree‐dimensional volume data sets from the axial upper mediastinal section were acquired from 37 normal pregnancies between 12 and 35 weeks' gestation. Thymus volume was calculated by virtual organ computer‐aided analysis by 2 separate examiners. In 12 cases, volumes were also acquired with 4‐dimensional sonography and spatiotemporal image correlation software to assess the variability in thymus size between the systolic and diastolic periods of fetal heart motion. Linear regression analysis was used to assess the relationship between the fetal thymus volume and gestational age. Paired Student t tests were used to evaluate both the level of agreement for interobserver and intraobserver variability and the difference between diastolic and systolic thymus volumes.ResultsIdentification of the borders of the thymus and calculation of its volume were successful in 28 patients (77.7%). Statistically significant linear growth of the thymus during pregnancy, from 12 to 35 weeks, was found. The growth coefficient for each gestational age was 0.43 (95% confidence interval, 0.355 to 0.504; P < .001). The difference in thymus size between systole and diastole was minor (0.0798 cm3; 95% confidence interval, –0.044 to 0.203 cm3). Interobserver and intraobserver variability was not statistically significant.ConclusionsAlthough the thymus has a complex shape, it was possible to determine its borders and to calculate its volume by virtual organ computer‐aided analysis in 77.7% of cases. Linear growth during pregnancy was found, and the minor changes during systole and diastole could be explained by condensation of the soft tissue of the thymus secondary to cardiac activity.
The Thy‐Box for Sonographic Assessment of the Fetal Thymus
Authors: Muñoz-Chápuli Mar , Gámez Francisco , Bravo Coral , Ortiz Luis , Pérez Ricardo , De León-Luis Juan A. 
Published: April 2015

ObjectivesTo assess the feasibility and reproducibility of fetal thy‐box visualization and to set normative data for the fetal thymus using this technique.MethodsWe performed a cross‐sectional observational study in pregnant women in their second trimester of pregnancy who attended the fetal medicine unit of the Hospital Gregorio Marañón from March 2011 to March 2013. Using thy‐box sonography, which sets boundaries within the thymus, we assessed the feasibility of the thy‐box and analyzed the factors related to its visualization. Measurements of the thy‐box anteroposterior and transverse diameters were performed in healthy fetuses. Interobserver agreement was studied for both items. We set normative data for the thy‐box diameters in singleton and twin pregnancies.ResultsA total of 337 patients from 15 to 37 weeks were recruited after exclusion criteria. Thy‐box feasibility was 74.2% (250 of 337). Nonfeasible cases were related to the fetal anterior spine and advanced gestational age. Assessment of the thy‐box anteroposterior and transverse diameters was achievable in 250 fetuses. Interobserver agreement was good for feasibility and measurements (κ = 0.80). Linear growth of the thy‐box in both diameters was observed in relation to gestational age during the second half of pregnancy. Thy‐box diameters did not show significant differences according to the type of gestation, fetal sex, or chorionicity.ConclusionsThy‐box diameters are achievable and reproducible by sonography in normal singleton and twin pregnancies during the second trimester; however, although feasible, the thy‐box transverse diameter measurement is not reliable beyond 28 weeks. Further studies are needed to evaluate thy‐box diameters in pathologic cases, especially conotruncal anomalies.
A comparison of plot‐based satellite and Earth system model estimates of tropical forest net primary production
Authors: Cleveland Cory C. , Taylor Philip , Chadwick K. Dana , Dahlin Kyla , Doughty Christopher E. , Malhi Yadvinder , Smith W. Kolby , Sullivan Benjamin W. , Wieder William R. , Townsend Alan R. 
Published: April 2015

AbstractNet primary production (NPP) by plants represents the largest annual flux of carbon dioxide (CO2) from the atmosphere to the terrestrial biosphere, playing a critical role in the global carbon (C) cycle and the Earth's climate. Rates of NPP in tropical forests are thought to be among the highest on Earth, but debates about the magnitude, patterns, and controls of NPP in the tropics highlight uncertainty in our understanding of how tropical forests may respond to environmental change. Here, we compared tropical NPP estimates generated using three common approaches: (1) field‐based methods scaled from plot‐level measurements of plant biomass, (2) radiation‐based methods that model NPP from satellite‐derived radiation absorption by plants, (3) and biogeochemical model‐based methods. For undisturbed tropical forests as a whole, the three methods produced similar NPP estimates (i.e., ~ 10 Pg C yr−1). However, the three different approaches produced vastly different patterns of NPP both in space and through time, suggesting that our understanding of tropical NPP is poor and that our ability to predict the response of NPP in the tropics to environmental change is limited. To address this shortcoming, we suggest the development of an expanded, high‐density, permanent network of sites where NPP is continuously evaluated using multiple approaches. Well‐designed NPP megatransects that include a high‐density plot network would significantly increase the accuracy and certainty in the observed rates and patterns of tropical NPP and improve the reliability of Earth system models used to predict NPP–carbon cycle–climate interactions into the future.
Source and sink carbon dynamics and carbon allocation in the Amazon basin
Authors: Doughty Christopher E. , Metcalfe D. B. , Girardin C. A. J. , Amezquita F. F. , Durand L. , Huaraca Huasco W. , Silva‐Espejo J. E. , Araujo‐Murakami A. , da Costa M. C. , da Costa A. C. L. , Rocha W. , Meir P. , Galbraith D. , Malhi Y. 
Published: April 2015

AbstractChanges to the carbon cycle in tropical forests could affect global climate, but predicting such changes has been previously limited by lack of field‐based data. Here we show seasonal cycles of the complete carbon cycle for 14, 1 ha intensive carbon cycling plots which we separate into three regions: humid lowland, highlands, and dry lowlands. Our data highlight three trends: (1) there is differing seasonality of total net primary productivity (NPP) with the highlands and dry lowlands peaking in the dry season and the humid lowland sites peaking in the wet season, (2) seasonal reductions in wood NPP are not driven by reductions in total NPP but by carbon during the dry season being preferentially allocated toward either roots or canopy NPP, and (3) there is a temporal decoupling between total photosynthesis and total carbon usage (plant carbon expenditure). This decoupling indicates the presence of nonstructural carbohydrates which may allow growth and carbon to be allocated when it is most ecologically beneficial rather than when it is most environmentally available.
Water circulation and global mantle dynamics: Insight from numerical modeling
Authors: Nakagawa Takashi , Nakakuki Tomoeki , Iwamori Hikaru 
Published: April 2015

AbstractWe investigate water circulation and its dynamical effects on global‐scale mantle dynamics in numerical thermochemical mantle convection simulations. Both dehydration‐hydration processes and dehydration melting are included. We also assume the rheological properties of hydrous minerals and density reduction caused by hydrous minerals. Heat transfer due to mantle convection seems to be enhanced more effectively than water cycling in the mantle convection system when reasonable water dependence of viscosity is assumed, due to effective slab dehydration at shallow depths. Water still affects significantly the global dynamics by weakening the near‐surface oceanic crust and lithosphere, enhancing the activity of surface plate motion compared to dry mantle case. As a result, including hydrous minerals, the more viscous mantle is expected with several orders of magnitude compared to the dry mantle. The average water content in the whole mantle is regulated by the dehydration‐hydration process. The large‐scale thermochemical anomalies, as is observed in the deep mantle, is found when a large density contrast between basaltic material and ambient mantle is assumed (4–5%), comparable to mineral physics measurements. Through this study, the effects of hydrous minerals in mantle dynamics are very important for interpreting the observational constraints on mantle convection.
Coupled simulations of Greenland Ice Sheet and climate change up to A.D. 2300
Authors: Vizcaino Miren , Mikolajewicz Uwe , Ziemen Florian , Rodehacke Christian B. , Greve Ralf , van den Broeke Michiel R. 
Published: April 2015

AbstractRecent observations indicate a high sensitivity of the Greenland Ice Sheet (GrIS) to climate change. We examine the coupling between the GrIS surface mass balance, elevation, and dynamical flow with one of the few coupled GrIS and atmosphere‐ocean general circulation models. Bidirectional coupling from the early Holocene reveals a growing present‐day GrIS in the absence of anthropogenic forcing. We identify atmospheric sources of biases in the simulated present‐day GrIS and assess the GrIS sensitivity to future greenhouse gas forcing through three Representative Concentration Pathways and their extensions and to climate variability. The elevation‐surface mass balance feedback contributes to future GrIS mass loss with 8–11% (by 2100), depending on the forcing scenario, and 24–31% (by 2300). Climate variability causes a 2.5 times spread in the magnitude of the simulated present‐day GrIS mass trends in a three‐member ensemble. Our results represent a first step toward more advanced higher resolution coupled modeling of GrIS and climate evolution.
Anisotropy and crystalline fabric of Whillans Ice Stream (West Antarctica) inferred from multicomponent seismic data
Authors: Picotti Stefano , Vuan Alessandro , Carcione José M. , Horgan Huw J. , Anandakrishnan Sridhar 
Published: April 2015

AbstractCrystal orientation fabric (COF) describes the intrinsic anisotropic nature of ice and is an important parameter for modeling glacier flow. We present the results of three‐component active‐source seismic observations from the Whillans Ice Stream (WIS), a fast‐flowing ice stream in West Antarctica. Surface‐wave dispersion analysis, ray tracing, and traveltime inversion of compressional (P) and shear (S) waves reveal the presence of transversely isotropic ice with a vertical axis of symmetry (VTI) beneath approximately 65 m of isotropic firn. The ice stream is characterized by weak anisotropy, involving an average ice thickness of approximately 780 m. The analysis indicates that about 95% of the ice mass is anisotropic, and the crystalline c axes span within an average broad cone angle of 73 ± 10° with respect to the vertical axis. Moreover, the mean temperature T (below the firn) estimated from seismic data is −15 ± 5°C. These data do not show evidence of englacial seismic reflectivity, which indicates the lack of abrupt changes in the COF. The presence of azimuthal anisotropy due to transversely compressive flow or fractures aligned along a preferential direction is also excluded. We suggest that the observed VTI ice structure is typical of large ice streams in regions where basal sliding and bed deformation dominate over internal glacial deformation.
Diurnal cycling of sea surface temperature, salinity, and current in the CESM coupled climate model
Authors: Large W. G. , Caron J. M. 
Published: April 2015

AbstractA simple scheme is developed to represent Sea Surface Diurnal Cycling (SSDC) in Coupled General Circulation Models (CGCM). It follows Zeng and Beljaars [2005], but in addition to a night‐time deep well‐mixed ocean boundary layer and a deep day‐time stable layer, a shallow sub‐grid‐scale stable diurnal boundary layer is allowed to develop during the day, followed by a deepening convective layer. These four regimes have empirical property profiles and their governing parameters are determined by comparison of idealized experiments with published in situ and satellite observations. Mixing across the base of the shallow stable layer is governed by a gradient Richardson number, so prognostic equations are solved for salinity and current, as well as temperature. A conclusion is that the timing of peak warming depends on diurnal shear. The SSDC is implemented in the Community Earth System Model (CESM) for multiple purposes: the maximum diurnal amplitude of warming is found to exceed 5°C and to be more than 2°C over most of the ocean; the global distribution of average day‐time minus night‐time SST is used to validate the SSDC against a satellite SST product; and the mean seasonal surface heat flux and precipitation from an uncoupled CESM atmosphere are used to show the climate impacts that might be expected in a CGCM. Two major conclusions are that these impacts are not negligible and that much of the observed signals of diurnal cycling are captured by SSDC without the computational expense of resolving the relevant ocean processes.
Recent topographic evolution and erosion of the deglaciated Washington Cascades inferred from a stochastic landscape evolution model
Authors: Moon Seulgi , Shelef Eitan , Hilley George E. 
Published: April 2015

AbstractIn this study, we model postglacial surface processes and examine the evolution of the topography and denudation rates within the deglaciated Washington Cascades to understand the controls on and time scales of landscape response to changes in the surface process regime after deglaciation. The postglacial adjustment of this landscape is modeled using a geomorphic‐transport‐law‐based numerical model that includes processes of river incision, hillslope diffusion, and stochastic landslides. The surface lowering due to landslides is parameterized using a physically based slope stability model coupled to a stochastic model of the generation of landslides. The model parameters of river incision and stochastic landslides are calibrated based on the rates and distribution of thousand‐year‐time scale denudation rates measured from cosmogenic 10Be isotopes. The probability distributions of those model parameters calculated based on a Bayesian inversion scheme show comparable ranges from previous studies in similar rock types and climatic conditions. The magnitude of landslide denudation rates is determined by failure density (similar to landslide frequency), whereas precipitation and slopes affect the spatial variation in landslide denudation rates. Simulation results show that postglacial denudation rates decay over time and take longer than 100 kyr to reach time‐invariant rates. Over time, the landslides in the model consume the steep slopes characteristic of deglaciated landscapes. This response time scale is on the order of or longer than glacial/interglacial cycles, suggesting that frequent climatic perturbations during the Quaternary may produce a significant and prolonged impact on denudation and topography.