bluuebunny/crossref_metadata_2025_split huggingface dataset:
Early Second‐Trimester Sonography to Improve the Fetal Anatomic Survey in Obese Patients
Authors: Gupta Simi , Timor-Tritsch Ilan E. , Oh Cheongeun , Chervenak Judith , Monteagudo Ana 
Published: August 2014

ObjectivesFetal anatomic surveys are difficult to perform on obese patients. However, there are limited data available on methods to improve the rate of complete anatomy scans in these patients. The objective of this study was to determine whether the addition of an early second‐trimester fetal anatomy scan improves the rate of complete anatomy scans in obese patients.MethodsWe conducted a prospective cohort study of 100 obese patients at a city hospital who were scheduled for a fetal anatomy scan using transvaginal and transabdominal sonography at 14 to 16 weeks (early anatomy scan) and an anatomy scan at 18 to 22 weeks (“routine” anatomy scan). Inclusion criteria were a body mass index of 30 kg/m2 or higher, singleton pregnancy, and presentation for prenatal care before 16 weeks. Data for the routine anatomy scan alone versus a combination of early and routine anatomy scans was calculated by the McNemar χ2 test for categorical variables and the Wilcoxon signed ranks test for continuous variables.ResultsThe addition of the early anatomy scan significantly increased the rate of complete anatomy scans from 42% to 51% (P < .01). It also significantly improved visualization of the head, thorax, and abdomen and significantly increased the mean number of items seen (P < .05).ConclusionsThe addition of an early second‐trimester fetal anatomy scan to a routine anatomy scan performed later in the second trimester significantly improves the rate of complete anatomy scans in obese patients.
Impact of New Society of Radiologists in Ultrasound Early First‐Trimester Diagnostic Criteria for Nonviable Pregnancy
Authors: Hu Maowen , Poder Liina , Filly Roy A. 
Published: August 2014

ObjectivesNew early first‐trimester diagnostic criteria for nonviable pregnancy recommended by the Society of Radiologists in Ultrasound via a multispecialty consensus panel extended the diagnostic size criteria of crown‐rump length from 5 to 7 mm for embryos without a heartbeat and mean sac diameter from 16 to 25 mm for “empty” sacs. Our study assessed the potential impact of the new criteria on the number of additional follow‐up sonograms these changes would engender.MethodsA retrospective study of all first‐trimester sonograms in women with first trimester bleeding from 1999 to 2008 was conducted. Everyone included in the study had a visible gestational sac in the uterus. There were no pregnancies of unknown location or ectopic pregnancies included in this study cohort. Pregnancy of unknown location was used to describe cases in which there were no signs of pregnancy inside or outside the uterus on transvaginal sonography despite a positive pregnancy test result. A total of 1013 patients met the inclusion criteria.ResultsSeven hundred fifty‐two patients (74%) had identifiable embryos, and 261 (26%) did not. Of those with an identifiable embryo, 286 (38%) had no detectable embryonic cardiac activity. The breakdown of crown‐rump lengths in this group was as follows: 100 measuring less than 5 mm, 36 measuring 5 to 7 mm, and 150 measuring 7 mm or greater. The breakdown of mean sac diameters in those without a visible embryo was as follows: 120 measuring less than 16 mm, 90 measuring 16 to 25 mm, and 51 measuring 25 mm or greater.ConclusionsWhen diagnosing a failed pregnancy, there can be no room for error. Only 126 of 1013 early pregnancies threatening to abort (12%) fell into the more conservative zones defined by the new compared to the former size criteria (crown‐rump length, 5–7 mm; mean sac diameter, 16–25 mm). Therefore, the potential impact of the new guidelines on follow‐up sonograms does not appear inordinate.
Value of Short‐Interval Computed Tomography When Sonography Fails to Visualize the Appendix and Shows Otherwise Normal Findings
Authors: Shah Bhavya R. , Stewart Jessica , Jeffery R. Brooke , Olcott Eric W. 
Published: August 2014

ObjectivesThe purpose of this study was to evaluate the type and incidence of disorders revealed by short‐interval computed tomography (CT) in patients with suspected appendicitis after graded compression sonography fails to reveal the appendix and shows otherwise normal findings.MethodsComputed tomographic findings and clinical courses were assessed retrospectively for 318 patients identified consecutively in a searchable database who met inclusion criteria specifying that sonography was the initial imaging examination for suspected appendicitis; sonography revealed nonvisualization of the appendix and otherwise normal results; and abdominopelvic CT was performed within 48 hours after sonography.ResultsOf the 318 patients, short‐interval CT revealed normal findings in 250 (78.6%). Appendicitis was revealed in 52 (16.4%) others, of whom 7 had perforation and all of whom had pathologic results confirming these CT findings. Important alternative diagnoses other than appendicitis were revealed in 16 (5.0%) others, including 2 (0.6%) who required urgent surgery and 14 (4.4%) who did not. No significant differences were observed between adult patients (>18 years) and pediatric patients.ConclusionsMost short‐interval CT scans in this clinical setting reveal normal findings, and relatively few disclose appendicitis or disorders that require urgent surgery. In view of concerns regarding radiation exposure associated with CT, these observations argue for the development of clinical triage methods that differentiate patients who are likely to benefit from short‐interval postsonography CT from those who are not.
Charcoal dispersion and deposition in boreal lakes from 3 years of monitoring: Differences between local and regional fires
Authors: Oris France , Ali Adam A. , Asselin Hugo , Paradis Laure , Bergeron Yves , Finsinger Walter 
Published: August 2014

AbstractTo evaluate the influence of long‐distance transport of charcoal particles on the detection of local wildfires from lake sediment sequences, we tracked three consecutive years of charcoal deposition into traps set within seven boreal lakes in northeastern Canada. Peaks in macroscopic charcoal accumulation (>150 µm) were linked to both local (inside the watershed) and regional wildfires. However, regional fires were characterized by higher proportions of small particles (<0.1 mm2) in charcoal assemblages. We conclude that the analysis of particle size distribution is useful to discriminate “true” local fires from regional wildfires.
The preparatory phase of the 2009 Mw 6.3 L'Aquila earthquake by improving the detection capability of low‐magnitude foreshocks
Authors: Sugan Monica , Kato Aitaro , Miyake Hiroe , Nakagawa Shigeki , Vuan Alessandro 
Published: August 2014

AbstractWe explored the detection capability of low‐magnitude earthquakes before the 6 April 2009 Mw 6.3 L'Aquila event by using a matched filter technique and 512 foreshocks as templates. We analyzed continuous waveforms from 10 broadband seismic stations in a 60 km radius from the epicenter and for ~3 months before the main shock. More than 3000 new events, mostly located on the main shock fault, were detected to define the spatial‐temporal evolution of micro‐seismicity. The foreshock sequence was active northwest of the Mw 6.3 hypocenter in January, then migrated toward it at a speed of ~0.5 km/day in middle of February. At that time, in a ~4 km2 patch close to the main shock nucleation point, the cumulative number of earthquakes gradually increased until the Mw 6.3 event. This patch, characterized by a low b‐value, played a key role in controlling the preparation stage to the 2009 L'Aquila main rupture.
Electron kappa distribution and quasi‐thermal noise
Authors: Yoon Peter H. 
Published: August 2014

AbstractSpacecraft measurements of charged particles in the solar wind show that their velocity distributions deviate from thermal Maxwellian model, having energetic components with quasi‐scale‐free power law velocity dependence, f ∼ v−α, in the high‐velocity range. It is customary to model such a feature by means of the kappa distribution, first introduced in the 1960s to empirically fit the data, but attempts have been made to understand the kappa distribution in terms of nonextensive statistical mechanics. A recent series of papers explore an alternative model, which may be interrelated with the nonextensive thermostatistical concept. According to the model, the electron kappa distribution is understood as a self‐consistent steady state solution of the weak turbulence equation in which the electrons and electrostatic Langmuir turbulence are in dynamic equilibrium state. These papers also compared the theoretical kappa parameter with observations of quiet time solar wind electrons near 1 AU. However, the electrostatic Langmuir turbulence, also known as the quasi‐thermal noise, requires a more in‐depth analysis. The present paper extends the recent theory by including a discussion of electrostatic fluctuations in greater detail, thus bringing the theory to a full closure.
Quantitative estimate of heat flow from a mid‐ocean ridge axial valley, Raven field, Juan de Fuca Ridge: Observations and inferences
Authors: Salmi Marie S. , Johnson H. Paul , Tivey Maurice A. , Hutnak Michael 
Published: August 2014

AbstractA systematic heat flow survey using thermal blankets within the Endeavour segment of the Juan de Fuca Ridge axial valley provides quantitative estimates of the magnitude and distribution of conductive heat flow at a mid‐ocean ridge, with the goal of testing current models of hydrothermal circulation present within newly formed oceanic crust. Thermal blankets were deployed covering an area of 700 by 450 m in the Raven Hydrothermal vent field area located 400 m north of the Main Endeavour hydrothermal field. A total of 176 successful blanket deployment sites measured heat flow values that ranged from 0 to 31 W m−2. Approximately 53% of the sites recorded values lower than 100 mW m−2, suggesting large areas of seawater recharge and advective extraction of lithospheric heat. High heat flow values were concentrated around relatively small “hot spots.” Integration of heat flow values over the Raven survey area gives an estimate of conductive heat output of 0.3 MW, an average of 0.95 W m−2, over the survey area. Fluid circulation cell dimensions and scaling equations allow calculation of a Rayleigh number of approximately 700 in Layer 2A. The close proximity of high and low heat flow areas, coupled with previous estimates of surficial seafloor permeability, argues for the presence of small‐scale hydrothermal fluid circulation cells within the high‐porosity uppermost crustal layer of the axial seafloor.
Impact of various observing systems on weather analysis and forecast over the Indian region
Authors: Singh Randhir , Ojha Satya P. , Kishtawal C. M. , Pal P. K. 
Published: August 2014

AbstractTo investigate the potential impact of various types of data on weather forecast over the Indian region, a set of data‐denial experiments spanning the entire month of July 2012 is executed using the Weather Research and Forecasting (WRF) model and its three‐dimensional variational (3DVAR) data assimilation system. The experiments are designed to allow the assessment of mass versus wind observations and terrestrial versus space‐based instruments, to evaluate the relative importance of the classes of conventional instrument such as radiosonde, and finally to investigate the role of individual spaceborne instruments. The moist total energy norm is used for validation and forecast skill assessment. The results show that the contribution of wind observations toward error reduction is larger than mass observations in the short range (48 h) forecast. Terrestrial‐based observations generally contribute more than space‐based observations except for the moisture fields, where the role of the space‐based instruments becomes more prevalent. Only about 50% of individual instruments are found to be beneficial in this experiment configuration, with the most important role played by radiosondes. Thereafter, Meteosat Atmospheric Motion Vectors (AMVs) (only for short range forecast) and Special Sensor Microwave Imager (SSM/I) are second and third, followed by surface observations, Sounder for Probing Vertical Profiles of Humidity (SAPHIR) radiances and pilot observations. Results of the additional experiments of comparative performance of SSM/I total precipitable water (TPW), Microwave Humidity Sounder (MHS), and SAPHIR radiances indicate that SSM/I is the most important instrument followed by SAPHIR and MHS for improving the quality of the forecast over the Indian region. Further, the impact of single SAPHIR instrument (onboard Megha‐Tropiques) is significantly larger compared to three MHS instruments (onboard NOAA‐18/19 and MetOp‐A).
Distribution and activity of ice wedges across the forest‐tundra transition, western Arctic Canada
Authors: Kokelj S. V. , Lantz T. C. , Wolfe S. A. , Kanigan J. C. , Morse P. D. , Coutts R. , Molina‐Giraldo N. , Burn C. R. 
Published: August 2014

AbstractRemote sensing, regional ground temperature and ground ice observations, and numerical simulation were used to investigate the size, distribution, and activity of ice wedges in fine‐grained mineral and organic soils across the forest‐tundra transition in uplands east of the Mackenzie Delta. In the northernmost dwarf‐shrub tundra, ice wedge polygons cover up to 40% of the ground surface, with the wedges commonly exceeding 3 m in width. The largest ice wedges are in peatlands where thermal contraction cracking occurs more frequently than in nearby hummocky terrain with fine‐grained soils. There are fewer ice wedges, rarely exceeding 2 m in width, in uplands to the south and none have been found in mineral soils of the tall‐shrub tundra, although active ice wedges are found there throughout peatlands. In the spruce forest zone, small, relict ice wedges are restricted to peatlands. At tundra sites, winter temperatures at the top of permafrost are lower in organic than mineral soils because of the shallow permafrost table, occurrence of phase change at 0°C, and the relatively high thermal conductivity of icy peat. Due to these factors and the high coefficient of thermal contraction of frozen saturated peat, ice wedge cracking and growth is more common in peatlands than in mineral soil. However, the high latent heat content of saturated organic active layer soils may inhibit freezeback, particularly where thick snow accumulates, making the permafrost and the ice wedges in spruce forest polygonal peatlands susceptible to degradation following alteration of drainage or climate warming.
Daily environmental differences in blood pressure and heart rate variability in healthy premenopausal women
Authors: James Gary D. , Bovbjerg Dana H. , Hill Leah A. 
Published: August 2014

ObjectivesAs daily environments change, behavior and activity also change and as blood pressure (BP) and heart rate (HR) are allostatically tied to these factors, one might expect that environments that elicit the greatest behavioral/activity variation should also evince the highest BP and HR variability [standard deviation (SD) or coefficient of variation (CV)]. The purpose of this study was to evaluate this premise.MethodsTwo hundred and six women (age = 37.6 ± 9.1 years) wore an ambulatory BP monitor on a midweek workday. All worked in clerical, technical, or professional positions. Ambulatory BP and HR Means, SDs and CVs at work (11 AM–3 PM), home (∼6–10 PM) and during sleep (∼10 PM–6 AM) were compared using repeated measures ANCOVA.ResultsMean BP and HR decreased from work and home to sleep [121 ± 11, 120 ± 11 vs. 107 ± 12 systolic; 82 ± 10, 80 ± 11 vs. 66 ± 11 diastolic; 79 ± 12, 80 ± 12 vs. 68 ± 11 HR (all P < 0.001)], while the CV of systolic and diastolic BP increased [0.06 ± 0.02, 0.07 ± 0.02 vs. 0.08 ± 0.03 systolic; 0.09 ± 0.03, 0.10 ± 0.04 vs. 0.12 ± 0.05 diastolic (P < 0.001)]. The HR SD decreased during sleep [8.1 ± 3.8, 8.2 ± 3.8 vs. 6.9 ± 3.2 (P < 0.001)].ConclusionsHR variability follows the expected variability pattern with behavior and activity, whereas BP does not. Am. J. Hum. Biol. 27:136–138, 2015. © 2014 Wiley Periodicals, Inc.
Gold(I)‐Catalyzed Diazo Coupling: Strategy towards Alkene Formation and Tandem Benzannulation
Authors: Zhang Daming , Xu Guangyang , Ding Dong , Zhu Chenghao , Li Jian , Sun Jiangtao 
Published: August 2014

AbstractA gold(I)‐catalyzed cross‐coupling of diazo compounds to afford tetrasubstituted alkenes has been developed by taking advantage of a trivial electronic difference between two diazo substrates. A N‐heterocyclic‐carbene‐derived gold complex is the most effective catalyst for this transformation. Based on this new strategy, a gold(I)‐initiated benzannulation has been achieved through a tandem reaction involving a diazo cross‐coupling, 6π electrocyclization, and oxidative aromatization.
Photocatalytic Synthesis of Dihydrobenzofurans by Oxidative [3+2] Cycloaddition of Phenols
Authors: Blum Travis R. , Zhu Ye , Nordeen Sarah A. , Yoon Tehshik P. 
Published: August 2014

AbstractWe report a protocol for oxidative [3+2] cycloadditions of phenols and alkenes applicable to the modular synthesis of a large family of dihydrobenzofuran natural products. Visible‐light‐activated transition metal photocatalysis enables the use of ammonium persulfate as an easily handled, benign terminal oxidant. The broad range of organic substrates that are readily oxidized by photoredox catalysis suggests that this strategy may be applicable to a variety of useful oxidative transformations.
Highly Diastereoselective and Enantiospecific Allylation of Ketones and Imines Using Borinic Esters: Contiguous Quaternary Stereogenic Centers
Authors: Chen Jack L.‐Y. , Aggarwal Varinder K. 
Published: August 2014

Abstract3,3‐Disubstituted allylic boronic esters are not sufficiently reactive to react with ketones and imines. However, they can be converted into the corresponding borinic esters by the sequential addition of nBuLi and TFAA. These reactive intermediates possess the perfect balance between reactivity and configurational stability. Their enhanced reactivity allows the highly selective allylation of both ketones and ketimines, and facile access to adjacent quaternary stereocenters with full stereocontrol. The versatility of the methodology is demonstrated in the construction of all possible stereoisomers of a quaternary‐quaternary motif and by the allylation of the heterocycles, dihydroisoquinoline and indole.
Arylacetylene‐Substituted Naphthalene Diimides with Dual Functions: Optical Waveguides and n‐Type Semiconductors
Authors: Li Yonghai , Zhang Guanxin , Zhang Wei , Wang Jianguo , Chen Xin , Liu Zitong , Yan Yongli , Zhao Yongsheng , Zhang Deqing 
Published: August 2014

AbstractNew arylacetylene‐substituted naphthalene diimides (NDIs) 1–6, with both light‐emitting and semiconducting functions, are reported. Among them, the crystal structure of 1 was determined. On the basis of their reduction potentials and thin‐film absorption spectra, the HOMO/LUMO energies of these modified NDIs were estimated. The results reveal that their HOMO/LUMO energies are slightly affected by the flanking aryl groups. The emission colors of these NDIs vary from green to red, and interestingly, they show aggregation‐induced emission enhancement behavior with fluorescence quantum yields reaching 9.86 % in the solid state. Microrods of 1, 3, and 5 show typical optical wave‐guiding behavior with relatively low optical‐loss coefficients. Organic field‐effect transistors with thin films of these NDIs were fabricated with conventional techniques. The results indicate that thin films of 2, 4, and 6, with long and branched alkyl chains, show air‐stable n‐type semiconducting properties with electron mobilities of up to 0.035 cm2 V−1 s−1 after thermal annealing, whereas 1, 3, and 5, with short alkyl chains, behave as n‐type semiconductors under a nitrogen atmosphere with electron mobilities of up to 0.075 cm2 V−1 s−1 after thermal annealing.
Inhomogeneous influence of the Atlantic warm pool on United States precipitation
Authors: Liu Hailong , Wang Chunzai , Lee Sang‐Ki , Enfield David 
Published: August 2014

AbstractOn interannual time scales, the warming of the Atlantic warm pool (AWP) is associated with a tripole sea surface temperature (SST) pattern in the North Atlantic and leads to more rainfall in the central and eastern US. On decadal‐to‐multidecadal time scales, the AWP warming corresponds to a basin‐wide warming pattern and results in less precipitation in the central and eastern US. The inhomogeneous relationship between the AWP warming and US rainfall on different time scales is largely due to the sign of mid‐latitude SST anomaly. The negative mid‐latitude SST anomaly associated with the tripole pattern may enhance the low sea level pressure over the northeastern North American continent and also enhance the barotropic response there of the AWP‐induced barotropic Rossby wave. This strengthened low pressure system, which is not exhibited when the warming is basin‐wide, results in a different moisture transport variation and thus the rainfall pattern over the United States.
Direct effect of lower‐tropospheric diabatic heating on surface wind over the equatorial Pacific
Authors: Li Lijuan , Wang Bin , Zhou Tianjun 
Published: August 2014

AbstractThe direct effect of lower‐tropospheric diabatic heating (DH) on surface circulation over the equatorial Pacific is revealed using the theoretical analysis and three atmospheric general circulation model (AGCM) simulations, only differing their moist processes. The AGCM results suggest that the insensitivity of surface wind to DH in the middle and high levels is closely associated with the vertical disagreement of DH between the layers below and above 925 hPa over the equatorial Pacific.
Towards an aerosol classification scheme for future EarthCARE lidar observations and implications for research needs
Authors: Groß S. , Freudenthaler V. , Wirth M. , Weinzierl B. 
Published: August 2014

AbstractOwing to the high variability of aerosols, and their different impact on the Earth's climate system, aerosol type classification from satellite measurements is of high importance. Polarization sensitive lidar measurements on board the future Earth Clouds, Aerosols and Radiation Explorer (EarthCARE) satellite mission will provide information to distinguish different aerosol types. We analyze whether former classification schemes based on lidar measurements at 532 nm are applicable to EarthCARE measurements at 355 nm. We compare coordinated lidar measurements at both wavelengths performed during five field experiments; adapt thresholds for aerosol classification with future spaceborne lidar measurements and identify limitations of the current state of knowledge.
Friction in mid‐latitude cyclones: an Ekman‐PV mechanism
Authors: Boutle I. A. , Belcher S. E. , Plant R. S. 
Published: August 2014

AbstractThe mechanism by which the atmospheric boundary layer reduces the intensity of mid‐latitude cyclones is investigated. It is demonstrated that two alternative theories, Ekman pumping and the baroclinic potential vorticity (PV) mechanism, in fact act in union to maximize the spin‐down. Ekman pumping aids the ventilation of PV from the boundary layer, and shapes the resulting PV anomaly into one of increased static stability. PV inversion techniques are used to demonstrate how this anomaly reduces the coupling between the upper‐ and lower‐levels within the cyclone, reducing the growth rate.