bluuebunny/crossref_metadata_2025 huggingface dataset:
Chronic Cough as a Symptom of Laryngopharyngeal Reflux—Two Case Reports
Authors: Kopka Monika , Małecka Milena , Stelmach Iwona
Published: December 2015

Laryngopharyngeal reflux (LPR) is a complex of symptoms caused by the backflow of gastric contents into the larynx, pharynx, nasopharynx, sinuses and even to the middle ear space.The symptomatology of LPR includes: chronic cough, hoarseness, throat clearing, laryngitis, “globus pharyngeus”, swallowing disturbances, postnasal drip, “fetor ex ore”. In the article, the authors present two boys with chronic cough, in one of them the asthma was suspected and antiasthmatic treatment was administrated; in our patients according to the 24-hour pharyngeal pH-metry LPR was diagnosed. The aim of this study was to emphasise that pediatricians should be able to recognise symptoms of LPR. The appropriate diagnosis and treatment leads the symptoms to subside.
Pulmonary Lesions in the Course of Gastric Cancer—Two Cases of Bard’s Syndrome
Authors: Zieliński Michał , Ochman Marek , Głowacki Jan , Kozielski Jerzy
Published: December 2015

The Bard’s syndrome is a medical condition related to miliary dissemination of gastric cancer to the lungs. Difficulties in diagnosis are associated with the need of differentiation between numerous diseases, which may manifest as disseminated lesions in the lung parenchyma on chest radiograph. Despite the advanced proliferative process, primary focus of neoplasm frequently remains subclinical. Metastatic lesions cause many symptoms in the respiratory system, suggesting primary pulmonary pathology. The Bard’s syndrome should be always taken into account in differential diagnosis of disseminated lesions, particularly due to prevalence of gastric cancer. The study presents two cases of patients with disseminated pulmonary lesions, corresponding to gastric cancer metastases on radiological imaging.
Groundwater Presents Many Treatment Challenges
Authors: Peterson Hans
Published: December 2015

It's vital to know your source's qualities to select the best approach to groundwater treatment
Key Federal Actions in 2015 Shape Future Course for Utilities
Authors: Roberson Alan
Published: December 2015

The twists and turns in Congress in 2015 haven't slowed the regulatory development process.
Coverage and system efficiencies of insecticide-treated nets in Africa from 2000 to 2017
Authors: Bhatt Samir , Weiss Daniel J , Mappin Bonnie , Dalrymple Ursula , Cameron Ewan , Bisanzio Donal , Smith David L , Moyes Catherine L , Tatem Andrew J , Lynch Michael , Fergus Cristin A , Yukich Joshua , Bennett Adam , Eisele Thomas P , Kolaczinski Jan , Cibulskis Richard E , Hay Simon I , Gething Peter W
Published: December 2015

Insecticide-treated nets (ITNs) for malaria control are widespread but coverage remains inadequate. We developed a Bayesian model using data from 102 national surveys, triangulated against delivery data and distribution reports, to generate year-by-year estimates of four ITN coverage indicators. We explored the impact of two potential 'inefficiencies': uneven net distribution among households and rapid rates of net loss from households. We estimated that, in 2013, 21% (17%–26%) of ITNs were over-allocated and this has worsened over time as overall net provision has increased. We estimated that rates of ITN loss from households are more rapid than previously thought, with 50% lost after 23 (20–28) months. We predict that the current estimate of 920 million additional ITNs required to achieve universal coverage would in reality yield a lower level of coverage (77% population access). By improving efficiency, however, the 920 million ITNs could yield population access as high as 95%.
Anxiety dissociates the adaptive functions of sensory and motor response enhancements to social threats
Authors: El Zein Marwa , Wyart Valentin , Grèzes Julie
Published: December 2015

Efficient detection and reaction to negative signals in the environment is essential for survival. In social situations, these signals are often ambiguous and can imply different levels of threat for the observer, thereby making their recognition susceptible to contextual cues – such as gaze direction when judging facial displays of emotion. However, the mechanisms underlying such contextual effects remain poorly understood. By computational modeling of human behavior and electrical brain activity, we demonstrate that gaze direction enhances the perceptual sensitivity to threat-signaling emotions – anger paired with direct gaze, and fear paired with averted gaze. This effect arises simultaneously in ventral face-selective and dorsal motor cortices at 200 ms following face presentation, dissociates across individuals as a function of anxiety, and does not reflect increased attention to threat-signaling emotions. These findings reveal that threat tunes neural processing in fast, selective, yet attention-independent fashion in sensory and motor systems, for different adaptive purposes.
Protein translocation channel of mitochondrial inner membrane and matrix-exposed import motor communicate via two-domain coupling protein
Authors: Banerjee Rupa , Gladkova Christina , Mapa Koyeli , Witte Gregor , Mokranjac Dejana
Published: December 2015

The majority of mitochondrial proteins are targeted to mitochondria by N-terminal presequences and use the TIM23 complex for their translocation across the mitochondrial inner membrane. During import, translocation through the channel in the inner membrane is coupled to the ATP-dependent action of an Hsp70-based import motor at the matrix face. How these two processes are coordinated remained unclear. We show here that the two domain structure of Tim44 plays a central role in this process. The N-terminal domain of Tim44 interacts with the components of the import motor, whereas its C-terminal domain interacts with the translocation channel and is in contact with translocating proteins. Our data suggest that the translocation channel and the import motor of the TIM23 complex communicate through rearrangements of the two domains of Tim44 that are stimulated by translocating proteins.
Mixture Models for Estimating Maximum Blood Flow Velocity
Authors: Marzban Caren , Gu Wenxiao , Mourad Pierre D.
Published: December 2015

Objectives

A gaussian mixture model (GMM) was recently developed for estimating the probability density function of blood flow velocity measured with transcranial Doppler ultrasound data. In turn, the quantiles of the probability density function allow one to construct estimators of the “maximum” blood flow velocity. However, GMMs assume gaussianity, a feature that is not omnipresent in observed data. The objective of this work was to develop mixture models that do not invoke the gaussian assumption.

Methods

Here, GMMs were extended to a skewed GMM and a nongaussian kernel mixture model. All models were developed on data from 59 patients with closed head injuries from multiple hospitals in the United States, with ages ranging from 13 to 81 years and Glasgow Coma Scale scores ranging from 3 to 11. The models were assessed in terms of the log likelihood (a goodness‐of‐fit measure) and via visual comparison with the underlying spectrograms.

Results

Among the models examined, the skewed GMM showed a significantly (P< .05) higher log likelihood for 56 of the 59 patients and produced maximum flow velocity estimates consistent with the observed spectrograms for all patients. Kernel mixture models are generally less “robust” in that their quality is inconsistent across patients.

Conclusions

Among the models examined, it was found that the skewed GMM provided a better model of the data both in terms of the quality of the fit and in terms of visual comparison of the underlying spectrogram and the estimated maximum blood flow velocity. Nongaussian mixture models have potential for even higher‐quality assessment of blood flow, but further development is called for.
Defining Competencies for Ultrasound‐Guided Bedside Procedures
Authors: Brown G. Mark , Otremba Mirek , Devine Luke A. , Gray Catherine , Millington Scott J. , Ma Irene W. Y.
Published: December 2015

Objectives

This study sought to define the competencies in ultrasound knowledge and skills that are essential for medical trainees to master to perform ultrasound‐guided central venous catheterization, thoracentesis, and paracentesis.

Methods

Experts in the 3 procedures were identified by a snowball technique through 3 Canadian tertiary academic health centers. Experts completed 2 rounds of surveys, including an 88‐item central venous catheterization survey, a 96‐item thoracentesis survey, and an 89‐item paracentesis survey. For each item, experts were asked to determine whether the knowledge/skill described was essential, important, or marginal. Consensus on an item was defined as agreement by at least 80% of the experts. For items on which consensus was not reached during the first round of surveys, a second survey was created in which the experts were asked to rate the item in a binary fashion (essential/important versus marginal/unimportant).

Results

Of the 27 experts invited to complete each survey, 25 (93%) completed the central venous catheterization survey; 22 (81%) completed the thoracentesis survey; and 23 (85%) completed the paracentesis survey. The experts represented 8 specialties from 8 cities within Canada. A total of 22, 32, and 28 items were determined to be essential competencies for central venous catheterization, thoracentesis, and paracentesis, respectively, whereas 47, 38, and 42 competencies were determined to be important, and 8, 13, and 10 were determined to be marginal. The ability to perform real‐time direct ultrasound guidance was considered essential only for the performance of central venous catheterization insertion.

Conclusions

Our study presents expert consensus‐derived ultrasound competencies that should be considered during the design and implementation of procedural skills training for learners.
Evaluating Spatiotemporal Image Correlation Technology as a Tool for Training Nonexpert Sonographers to Perform Examinations of the Fetal Heart
Authors: Avnet Hagai , Mazaaki Eyal , Shen Ori , Cohen Sarah , Yagel Simcha
Published: December 2015

Objectives

We aimed to evaluate the use of spatiotemporal image correlation (STIC) as a tool for training nonexpert examiners to perform screening examinations of the fetal heart by acquiring and examining STIC volumes according to a standardized questionnaire based on the 5 transverse planes of the fetal heart.

Methods

We conducted a prospective study at 2 tertiary care centers. Two sonographers without formal training in fetal echocardiography received theoretical instruction on the 5 fetal echocardiographic transverse planes, as well as STIC technology. Only women with conditions allowing 4‐dimensional STIC volume acquisitions (grayscale and Doppler) were included in the study. Acquired volumes were evaluated offline according to a standardized protocol that required the trainee to mark 30 specified structures on 5 required axial planes. Volumes were then reviewed by an expert examiner for quality of acquisition and correct identification of specified structures.

Results

Ninety‐six of 112 pregnant women examined entered the study. Patients had singleton pregnancies between 20 and 32 weeks' gestation. After an initial learning curve of 20 examinations, trainees succeeded in identifying 97% to 98% of structures, with a highly significant degree of agreement with the expert's analysis (P < .001). A median of 2 STIC volumes for each examination was necessary for maximal structure identification. Acquisition quality scores were high (8.6–8.7 of a maximal score of 10) and were found to correlate with identification rates (P = .017).

Conclusions

After an initial learning curve and under expert guidance, STIC is an excellent tool for trainees to master extended screening examinations of the fetal heart.
Sonographic Evaluation of Diaphragmatic Excursion and Thickness in Healthy Infants and Children
Authors: El-Halaby Hanan , Abdel-Hady Hesham , Alsawah Gehan , Abdelrahman Ashraf , El-Tahan Hanem
Published: December 2015

Objectives

M‐mode sonography is a noninvasive method for detection of diaphragmatic excursion and thickness. A few studies have assessed diaphragmatic kinetics in children with diaphragmatic paresis and paralysis, but to our knowledge, no data about normal values in pediatrics are available. The aims of this study were to determine reference values for diaphragmatic excursion and thickness, as evaluated by sonography in healthy infants and children, and identify correlations between them and anthropometric measurements, age, and sex.

Methods

A total of 400 healthy participants aged between 1 month and 16 years, divided into 4 equal groups (group 1, 1 month–2 years; group 2, 2–6 years; group 3, 6–12 years); and group 4, 12–16 years) were studied. M‐mode sonography was used to measure the excursion and thickness of the right and left hemidiaphragms (using the liver and spleen as acoustic windows, respectively).

Results

Reference values for diaphragmatic excursion and thickness were determined in different age groups of healthy infants and children. There were no significant differences with respect to sex. Significant positive correlations were found between excursion of the right hemidiaphragm and body weight in all age groups (r = 0.52, 0.25, 0.27. and 0.20; P < .001, .013, .011, and .047 for groups 1–4, respectively). We plotted percentile curves for right diaphragmatic excursion against body weight.

Conclusions

This study provides reference values for diaphragmatic excursion and thickness in healthy infants and children. Percentile curves for right diaphragmatic excursion plotted against body weight were plotted.
B‐Lines on Pediatric Lung Sonography
Authors: Martelius Laura , Heldt Henna , Lauerma Kirsi
Published: December 2015

Objectives

Sonographic artifacts known as B‐lines can been used to estimate alterations of lung parenchyma. Multiple B‐lines on sonography are seen in congestive heart disease, interstitial lung disease, respiratory infections, and neonates. The aim of this study was to compare the amount of B‐lines on sonography to the extent of parenchymal changes on computed tomography (CT) in children.

Methods

Lung sonography was performed on 60 patients aged 18 years and younger referred for chest CT at our institution. B‐lines were counted from 5 anterolateral intercostal spaces bilaterally. The CT findings were documented and graded as absent, minimal, partial, or complete.

Results

The number of B‐lines on sonography increased consistently with the growing extent of parenchymal changes on CT. The differences in the B‐line counts between the patients grouped according to the extent of parenchymal changes on CT were statistically significant except between patients with minimal and no changes (P < .01 Kruskal‐Wallis and Tukey tests).

Conclusions

The number of B‐lines on sonography correlates with the extent of parenchymal changes on CT. Various parenchymal changes were seen in patients with B‐lines on sonography. B‐lines were more frequently seen in patients with no changes on CT when imaged during general anesthesia.
Language of Transducer Manipulation
Authors: Bahner David P. , Blickendorf J. Matthew , Bockbrader Marcia , Adkins Eric , Vira Amar , Boulger Creagh , Panchal Ashish R.
Published: December 2015

There is a need for consistent, repetitive, and reliable terminology to describe the basic manipulations of the ultrasound transducer. Previously, 5 basic transducer motions have been defined and used in education. However, even with this effort, there is still a lack of consistency and clarity in describing transducer manipulation and motion. In this technical innovation, we describe an expanded definition of transducer motions, which include movements to change the transducer's angle of insonation to the target as well as the location on the body to optimize the ultrasound image. This new terminology may allow for consistent teaching and improved communication in the process of image acquisition.
Comparative Effectiveness of Two Ultrasound‐Guided Regional Block Techniques for Surgical Anesthesia in Open Unilateral Inguinal Hernia Repair
Authors: Steffel Lauren , Kim T. Edward , Howard Steven K. , Ly Daphne P. , Kou Alex , King Robert , Mariano Edward R.
Published: December 2015

Transversus abdominis plane (TAP) and ilioinguinal/iliohypogastric (II/IH) nerve blocks have been described as analgesic adjuncts for inguinal hernia repair, but the efficacy of these techniques in providing intraoperative anesthesia, either individually or together, is not known. We designed this retrospective cohort study to test the hypothesis that combining TAP and II/IH nerve blocks (“double TAP” technique) results in greater accordance between the preoperative anesthetic plan and actual anesthetic technique provided when compared to TAP alone. Based on this study, double TAP may be preferred for patients undergoing open inguinal hernia repair who wish to avoid general anesthesia.
Multiarray rupture imaging of the devastating 2015 Gorkha, Nepal, earthquake sequence
Authors: Zhang Hao , van der Lee Suzan , Ge Zengxi
Published: December 2015

A rapid, robust multiarray backprojection method was applied to image the rupture pattern of the 2015 Gorkha, Nepal Mw7.8 main shock and its Mw7.3 aftershock. Backprojected teleseismic P wave trains from three regional seismic arrays in Europe, Australia, and Alaska show that both earthquakes ruptured unilaterally and primarily eastward, with rupture speeds potentially decreasing with depth. The rupture of the main shock first extended ESEward at ∼3.5 km/s over ∼120 km, with later rupture propagation further downdip on the eastern segment at ∼2.1 km/s. The aftershock ruptured the fault SE of the main shock's ruptured plane. It began to rupture updipward for ∼20 km at a speed around 1.2 km/s, then it may have accelerated to 3.5 km/s for the next 50 km. The apparent depth‐dependent rupture speeds of the two earthquakes may be caused by along‐dip heterogeneities in fault strength, with a higher stress concentration on the updip part of the Nepalese Main Himalayan Thrust.
Simulated effects of southern hemispheric wind changes on the Pacific oxygen minimum zone
Authors: Getzlaff Julia , Dietze Heiner , Oschlies Andreas
Published: December 2015

A coupled ocean biogeochemistry‐circulation model is used to investigate the impact of observed past and anticipated future wind changes in the Southern Hemisphere on the oxygen minimum zone in the tropical Pacific. We consider the industrial period until the end of the 21st century and distinguish effects due to a strengthening of the westerlies from effects of a southward shift of the westerlies that is accompanied by a poleward expansion of the tropical trade winds. Our model results show that a strengthening of the westerlies counteracts part of the warming‐induced decline in the global marine oxygen inventory. A poleward shift of the trade‐westerlies boundary, however, triggers a significant decrease of oxygen in the tropical oxygen minimum zone. In a business‐as‐usual CO2 emission scenario, the poleward shift of the trade‐westerlies boundary and warming‐induced increase in stratification contribute equally to the expansion of suboxic waters in the tropical Pacific.
Cold ion heating at the dayside magnetopause during magnetic reconnection
Authors: Toledo‐Redondo S. , André M. , Vaivads A. , Khotyaintsev Yu. V. , Lavraud B. , Graham D. B. , Divin A. , Aunai N.
Published: December 2015

Cold ions of ionospheric origin are known to be present in the magnetospheric side of the Earth's magnetopause. They can be very abundant, with densities up to 100 cm−3. These cold ions can mass load the magnetosphere, changing global parameters of magnetic reconnection, like the Alfvén speed or the reconnection rate. In addition they introduce a new length scale related to their gyroradius and kinetic effects which must be accounted for. We report in situ observations of cold ion heating in the separatrix owing to time and space fluctuations of the electric field. When this occurs, the cold ions are preheated before crossing the Hall electric field barrier. However, when this mechanism is not present cold ions can be observed well inside the reconnection exhaust. Our observations suggest that the perpendicular cold ion heating is stronger close to the X line owing to waves and electric field gradients linked to the reconnection process.
Quantitative prediction of type II solar radio emission from the Sun to 1 AU
Authors: Schmidt J. M. , Cairns Iver H.
Published: December 2015

Coronal mass ejections (CMEs) are frequently associated with shocks and type II solar radio bursts. Despite involving fundamental plasma physics and being the archetype for collective radio emission from shocks, type II bursts have resisted detailed explanation for over 60 years. Between 29 November and 1 December 2013 the two widely separated spacecraft STEREO A and B observed a long lasting, intermittent, type II radio burst from ≈4 MHz to 30 kHz (harmonic), including an intensification when the CME‐driven shock reached STEREO A. We demonstrate the first accurate and quantitative simulation of a type II burst from the high corona (near 11 solar radii) to 1 AU for this event with a combination of a data‐driven three‐dimensional magnetohydrodynamic simulation for the CME and plasma background and an analytic quantitative kinetic model for the radio emission.
Validation of simulated hurricane drop size distributions using polarimetric radar
Authors: Brown Bonnie R. , Bell Michael M. , Frambach Andrew J.
Published: December 2015

Recent upgrades to the U.S. radar network now allow for polarimetric measurements of landfalling hurricanes, providing a new data set to validate cloud microphysical parameterizations used in tropical cyclone simulations. Polarimetric radar reflectivity and differential reflectivity simulated by the Weather Research and Forecasting model were compared with real radar observations from 2014 in Hurricanes Arthur and Ana. Six different microphysics parameterizations were tested that were able to capture the major features of both hurricanes, including accurate tracks, precipitation asymmetry, and the approximate intensity of the storms. A high correlation between simulated intensity and rainfall across schemes suggests an intimate link between the latent heating produced by the microphysics and the storm dynamics. Most of the parameterizations produced a higher frequency of larger raindrops than observed. The Thompson aerosol‐aware bulk and explicit spectral bin microphysical schemes showed the best fidelity to the observations at a higher computational cost.
Influence of intermittency on the anisotropy of magnetic structure functions of solar wind turbulence
Authors: Pei Zhongtian , He Jiansen , Wang Xin , Tu Chuanyi , Marsch Eckart , Wang Linghua , Yan Limei
Published: December 2015

Intermittency appears to be connected with the spectral anisotropy of solar wind turbulence. We use the Local Intermittency Measure to identify and remove intermittency from the magnetic field data measured by the Ulysses spacecraft in fast solar wind. Structure functions are calculated based on the time sequences as obtained before and after removing intermittency and arranged by time scale (τ) and ΘRB (the angle between local mean magnetic field B0 and radial direction R). Thus, the scaling exponent (ξ(p, ΘRB)) of every structure function of order (p) is obtained for different angles. Before removing intermittency, ξ(p, ΘRB) shows a distinctive dependence on ΘRB: from monofractal scaling law at ΘRB ~0° to multifractal scaling law at ΘRB ~90°. In contrast after eliminating the intermittency, ξ(p, ΘRB) is found to be more monofractal for all ΘRB. The extended structure‐function model is applied to ξ(p, ΘRB), revealing differences of its fitting parameters α (a proxy of the power spectral index) and P1 (fragmentation fraction) for the cases with and without intermittency. Parameter α shows an evident angular trend falling from 1.9 to 1.6 for the case with intermittency but has a relatively flat profile around 1.8 for the case without intermittency. Parameter P1 rises from around 0.5 to above 0.8 with increasing ΘRB for the intermittency case and is located between 0.5 and 0.8 for the case lacking intermittency. Therefore, we may infer that it is the anisotropy of intermittency that causes the scaling anisotropy of energy spectra and the unequal fragmentation of energy cascading.
A new approach to identify interplanetary Alfvén waves and to obtain their frequency properties
Authors: Li H. , Wang C. , Chao J. K. , Hsieh W. C.
Published: December 2015

Conventional diagnosis of interplanetary Alfvén waves requires an accurately determined de Hoffmann‐Teller (HT) frame or background magnetic field. For simplicity, the averaged HT frame and the mean value of the magnetic field are often used in the literature. However, HT frame can change quite fast in high‐speed solar wind streams, and it is not always appropriate to take the average value of the magnetic field to be the background state. In order to reduce the uncertainty introduced by determining HT frame and background magnetic field, we propose a new approach for identifying large‐amplitude interplanetary Alfvén waves. This new approach is independent of HT frame and of background magnetic field. Instead of the original data sets, the band‐pass filtered signals of plasma velocity and magnetic field observations are used to check the Walén relation. The robustness of this technique is verified by applying to simulated pure Alfvén waves with two separate frequencies and contaminated by pink colored noises in a varying solar wind stream. Furthermore, in our approach, more properties of Alfvén waves in frequency domain can be obtained, which have been rarely discussed before. Our analysis technique is applied to two intervals of solar wind high‐speed streams, and it is shown that large‐amplitude Alfvén waves near 1 AU are frequently found during these two intervals.
Scattering characteristics and imaging of energetic neutral atoms from the Moon in the terrestrial magnetosheath
Authors: Lue Charles , Futaana Yoshifumi , Barabash Stas , Saito Yoshifumi , Nishino Masaki , Wieser Martin , Asamura Kazushi , Bhardwaj Anil , Wurz Peter
Published: December 2015

We study hydrogen energetic neutral atom (ENA) emissions from the lunar surface, when the Moon is inside the terrestrial magnetosheath. The ENAs are generated by neutralization and backscattering of incident protons of solar wind origin. First, we model the effect of the increased ion temperature in the magnetosheath (>10 times larger than that in the undisturbed solar wind) on the ENA scattering characteristics. Then, we apply these models to ENA measurements by Chandrayaan‐1 and simultaneous ion measurements by Kaguya at the Moon, in the magnetosheath. We produce maps of the ENA scattering fraction, covering a region at the lunar near‐side that includes mare and highland surfaces and several lunar magnetic anomalies. We see clear signatures of plasma shielding by the magnetic anomalies. The maps are made at different lunar local times, and the results indicate an extended influence and altered morphology of the magnetic anomalies at shallower incidence angles of the magnetosheath protons. The scattering fraction from the unmagnetized regions remains consistent with that in the undisturbed solar wind (10%–20%). Moreover, the observed ENA energy spectra are well reproduced by our temperature‐dependent model. We conclude that the ENA scattering process is unchanged in the magnetosheath. Similarly to the undisturbed solar wind case, it is only magnetic anomalies that provide contrast in the ENA maps, not any selenomorphological features such as mare and highland regions.
Midlatitude ionospheric responses to the 2013 SSW under high solar activity
Authors: Chen Gang , Wu Chen , Zhang Shaodong , Ning Baiqi , Huang Xueqin , Zhong Dingkun , Qi Hao , Wang Jin , Huang Liang
Published: December 2015

Ionospheric responses to sudden stratospheric warming (SSW) are not well understood, particularly in the midlatitudes and under high solar conditions. During the 2013 SSW, ionospheric disturbances were observed in eight locations on the meridional chain from 30.5°N to 42.8°N in northern China. The midlatitude ionosphere responded strongly to the SSW despite being under high solar flux. The F2 layer maximum electric density increased by more than 80%, and the peak height was elevated more than 60 km. Well‐set and organized semidiurnal variations were recorded in early and middle January during the SSW in eight observation locations. The expected foF2 decrease in the afternoon hours was not clearly discernible; however, nighttime enhancements occurred frequently. The time‐period spectra of the average foF2 and zonal winds and meridional winds at altitudes of 86–95 km presented quasi‐16 day planetary wave‐like oscillations during the warming event. The coupling between the atmosphere and ionosphere may be strengthened by the quasi‐16 day waves. The amplified diurnal, semidiurnal, and terdiurnal tides in foF2 were also recorded during the warming, in good agreement with earlier observations. Importantly, the variations in the semidiurnal tides included a 16 day periodic component, indicating that the modulated semidiurnal tides may transmit these 16 day planetary wave‐like oscillations to the F region through wind dynamo. Although the PW‐tide interaction theory is not novel, it is of significance in the midlatitude ionospheric response to SSW.
Electron scattering by magnetosonic waves in the inner magnetosphere
Authors: Ma Qianli , Li Wen , Thorne Richard M. , Bortnik Jacob , Kletzing C. A. , Kurth W. S. , Hospodarsky G. B.
Published: December 2015

We investigate the importance of electron scattering by magnetosonic waves in the Earth's inner magnetosphere. A statistical survey of the magnetosonic wave amplitude and wave frequency spectrum, as a function of geomagnetic activity, is performed using the Van Allen Probes wave measurements and is found to be generally consistent with the wave distribution obtained from previous spacecraft missions. Outside the plasmapause the statistical frequency distribution of magnetosonic waves follows the variation of the lower hybrid resonance frequency, but this trend is not observed inside the plasmasphere. Drift and bounce averaged electron diffusion rates due to magnetosonic waves are calculated using a recently developed analytical formula. The resulting timescale of electron energization during disturbed conditions (when AE* > 300 nT) is more than 10 days. We perform a 2‐D simulation of the electron phase space density evolution due to magnetosonic wave scattering during disturbed conditions. Outside the plasmapause, the waves accelerate electrons with pitch angles between 50° and 70° and form butterfly pitch angle distributions at energies from ~100 keV to a few MeV over a timescale of several days; whereas inside the plasmapause, the electron acceleration is very weak. Our study suggests that intense magnetosonic waves may cause the butterfly distribution of radiation belt electrons especially outside the plasmapause, but electron acceleration due to magnetosonic waves is generally not as effective as chorus wave acceleration.
ULF geomagnetic and polar cap potential signatures in the temperature and zonal wind reanalysis data in Antarctica
Authors: Regi M. , De Lauretis M. , Redaelli G. , Francia P.
Published: December 2015

In the present study we investigated the possible coupling between geomagnetic activity and the low atmosphere dynamics in the polar cap. We compared daily values of the ERA‐Interim temperature and zonal wind over Antarctica, with the daily geomagnetic ULF power, in the Pc5 (1–7 mHz), Pc1, and Pc2 (100 mHz–1 Hz) frequency ranges, at Terra Nova Bay (Antarctica, corrected geomagnetic latitude λ ~ 80°S) and with solar wind data during 2007, in correspondence to the last declining phase of the solar cycle 23. We found a high and statistically significant correspondence of temperature and zonal wind fluctuations in the stratosphere and troposphere with geomagnetic ULF power fluctuations at the ~27 day periodicity, with a substantial reduction at the tropopause height. A similar, clear relationship between the meteorological parameters and the polar cap potential difference was also observed. The results suggest that the changes in the atmospheric conductivity, due to energetic electrons precipitation driven by the ULF waves, as well as the high latitude potential variations, both associated to high geomagnetic activity, can affect the atmospheric dynamics.
Triggered tectonic tremor in various types of fault systems of Japan following the 2012 Mw8.6 Sumatra earthquake
Authors: Chao Kevin , Obara Kazushige
Published: December 2015

Tectonic tremor, an extremely stress‐sensitive seismic phenomenon occurring in the brittle‐ductile transition section of a fault, is associated with the shearing mechanism of slow slip. Observations of triggered tremor can facilitate the evaluation of the existence of background ambient tremor and slow‐slip events. This paper presents widespread triggered tremor sources in Japan initiated by the surface waves of the 2012 Mw8.6 Sumatra earthquake on strike‐slip and thrust faults, in the deep volcanic low‐frequency earthquake active area, in the shallow tectonic tremor and very low frequency earthquake active regions, and in the subduction zone. In most regions, the amplitudes of triggered tremor are generally logarithmically proportional to the dynamic stress caused by various triggering earthquakes. Our observations suggest that triggered tremor in the newly discovered sources is the result of a more rapid rate of background ambient tremor, and evidence has suggested the existence of ambient tremor in some regions.
An analysis of five negative sprite‐parent discharges and their associated thunderstorm charge structures
Authors: Boggs Levi D. , Liu Ningyu , Splitt Michael , Lazarus Steven , Glenn Chad , Rassoul Hamid , Cummer Steven A.
Published: December 2015

In this study we analyze the discharge morphologies of five confirmed negative sprite‐parent discharges and the associated charge structures of the thunderstorms that produced them. The negative sprite‐parent lightning took place in two thunderstorms that were associated with a tropical disturbance in east central and south Florida. The first thunderstorm, which moved onshore in east central Florida, produced four of the five negative sprite‐parent discharges within a period of 17 min, as it made landfall from the Atlantic Ocean. These negative sprite‐parents were composed of bolt‐from‐the‐blue (BFB), hybrid intracloud‐negative cloud‐to‐ground (IC‐NCG), and multicell IC‐NCGs discharges. The second thunderstorm, which occurred inland over south Florida, produced a negative sprite‐parent that was a probable hybrid IC‐NCG discharge and two negative gigantic jets (GJs). Weakened upper positive charge with very large midlevel negative charge was inferred for both convective cells that initiated the negative‐sprite‐parent discharges. Our study suggests tall, intense convective systems with high wind shear at the middle to upper regions of the cloud accompanied by low cloud‐to‐ground (CG) flash rates promote these charge structures. The excess amount of midlevel negative charge results in these CG discharges transferring much more charge to ground than typical negative CG discharges. We find that BFB discharges prefer an asymmetrical charge structure that brings the negative leader exiting the upper positive charge region closer to the lateral positive screening charge layer. This may be the main factor in determining whether a negative leader exiting the upper positive region of the thundercloud forms a BFB or GJ.
Late Holocene climate: Natural or anthropogenic?
Authors: Ruddiman W. F. , Fuller D. Q. , Kutzbach J. E. , Tzedakis P. C. , Kaplan J. O. , Ellis E. C. , Vavrus S. J. , Roberts C. N. , Fyfe R. , He F. , Lemmen C. , Woodbridge J.
Published: December 2015

For more than a decade, scientists have argued about the warmth of the current interglaciation. Was the warmth of the preindustrial late Holocene natural in origin, the result of orbital changes that had not yet driven the system into a new glacial state? Or was it in considerable degree the result of humans intervening in the climate system through greenhouse gas emissions from early agriculture? Here we summarize new evidence that moves this debate forward by testing both hypotheses. By comparing late Holocene responses to those that occurred during previous interglaciations (in section 2), we assess whether the late Holocene responses look different (and thus anthropogenic) or similar (and thus natural). This comparison reveals anomalous (anthropogenic) signals. In section 3, we review paleoecological and archaeological syntheses that provide ground truth evidence on early anthropogenic releases of greenhouse gases. The available data document large early anthropogenic emissions consistent with the anthropogenic ice core anomalies, but more information is needed to constrain their size. A final section compares natural and anthropogenic interpretations of the δ13C trend in ice core CO2.
Trends in Multiresidue Analysis
Authors: Moreno‐González David , Lara Francisco J. , del Olmo‐Iruela Monsalud , García‐Campaña Ana M.
Published: December 2015

The global concern about food safety and environment quality has produced the development of a legal framework to control residues of organic compounds (e.g. pesticides and veterinary and human drugs). In this context, the establishment of analytical methods achieving satisfactory performances in terms of sensitivity, selectivity, resolution, identification, sample throughput, and applicability has been mandatory. Multiresidue methods based on chromatographic techniques, mainly gas chromatography (GC) and liquid chromatography (LC), coupled to mass spectrometry (MS), have been applied and sample preparation has evolved through the development of miniaturized and environmentally friendly procedures according to the Green Chemistry. In addition, generic extraction procedures for multiclass analysis have been optimized, increasing sample throughput. Capillary electrophoresis (CE) has emerged as an alternative to LC and GC, owing to the development of on‐line preconcentration strategies for increasing sensitivity. This article aims to show an overview about the current trends in the analysis of pesticide and drugs in food and environmental samples, discussing the relevant advances in sample treatments and the technological evolution of the instrumental techniques. We hope to offer with this article a critical review of the analytical possibilities for routine analysis laboratories.
Greener Helicopters
Authors: Russell Carl R. , Young Larry A. , Yamauchi Gloria K. , Johnson Wayne , Boyd D. Douglas , Gorton Susan A. , Snyder Christopher A. , Kohlman Lee W.
Published: December 2015

Helicopter and vertical takeoff and landing (VTOL) operations present multiple environmental challenges in a world where industrialized nations are adopting stricter regulations on air pollution and noise. New vehicles will need to be designed for minimal environmental impact, particularly with respect to CO2emissions and noise footprint. This chapter describes the issues confronting today's rotorcraft, and outlines technology options for developing VTOL vehicle designs with green propulsion systems, reducing rotorcraft noise, and applying “green metrics” to rotorcraft design.
Advanced Engine Designs and Concepts Beyond the Geared Turbofan
Authors: Perkins H. Douglas , Paxson Daniel E. , Snyder Christopher A.
Published: December 2015

The fundamental aircraft engine performance design drivers of propulsive efficiency, cycle thermal efficiency, and engine thrust to weight, along with underlying operational considerations of safety, reliability, and cost, have produced today's state‐of‐the‐art high bypass ratio turbofan found on virtually all commercial aircraft. These same engine performance parameters will continue to drive future aircraft propulsion system design, but will likely require significant changes in engine architecture and engine/airframe integration. Concepts such as the open rotor, distributed propulsion, electric and hybrid gas turbine/electric propulsion, and boundary layer ingestion could significantly alter the way future aircraft appear to the average passenger. Less visibly, alternate engine thermodynamic cycles, such as pressure gain combustion, alternative fuels, and real‐time engine health and performance monitoring may also work to improve engine performance. This chapter examines the role that various advanced propulsion concepts may have in continuing the steady improvement in aircraft propulsion performance that has taken place over the last 100+ years and how these concepts can contribute to reducing the environmental impact of aviation.
Geared Turbofan™ Engine: Driven by Innovation
Authors: Sheridan William , McCune Michael , Winter Michael
Published: December 2015

The use of gear systems in turbofan engines dates to the early 1970's with the introduction of the Lycoming ALF502 and the Garrett TFE731. In 2008 Pratt & Whitney (P&W) introduced the PW1000G PurePower® engine product line as a breakthrough in turbine engine design. There are several factors that make the PW1000G family more significant than previous machines. The first difference is the physical size of the fan drive gear system (FDGS) which transmits roughly three to four times more power than the aforementioned existing geared turbofan engines. The second major difference is the efficiency of the FDGS which reduces heat loss to a fraction of transmitted power. Finally, the reliability and time on wing of the FDGS will be comparable to any other component found in the cold section of the engine and will stay on wing for at least 30,000 flight hours before needing its first overhaul. All of these factors have transformed the FDGS development task from a simple gear design to a gear challenge. This new technology will bring cleaner, quieter and more efficient high bypass ratio jet engines to the customer.
Progress in Open Rotor Research
Authors: Van Zante Dale E.
Published: December 2015

In response to the 1970s oil crisis, NASA created the Advanced Turboprop Project (ATP) to mature technologies for high‐speed propellers to enable large reductions in fuel burn relative to turbofan engines of that era. Both single rotation and contra‐rotation concepts were designed and tested in ground‐based facilities as well as in flight. Some novel concepts/configurations were proposed as part of the effort. The high‐speed propeller concepts did provide fuel burn savings, albeit with some acoustics and structural challenges to overcome. When fuel prices fell, the business case for radical new engine configurations collapsed and the research emphasis returned to high‐bypass‐ducted configurations.

With rising oil prices and increased environmental concerns, there is renewed interest in high‐speed propeller‐based engine architectures. Contemporary analysis tools for aerodynamics and aeroacoustics have enabled a new era of blade designs that have both high efficiency and lower noise characteristics. A recent series of tests in the United States have characterized the aerodynamic performance and noise from these modern contra‐rotating propeller designs. Additionally, the installation and noise shielding aspects for conventional airframes and blended wing bodies have been studied.

Historical estimates of “propfan” performance have relied on legacy propeller performance and acoustics data. Current system studies make use of the modern propeller data with higher fidelity installation effects data to estimate the performance of a contemporary aircraft system with favorable results. This chapter presents the current state of high‐speed propeller/open rotor research in the United States from an overall viewpoint of the various ongoing efforts, including the current projections for the technology.
Green Aircraft Operations
Authors: Reynolds Tom G.
Published: December 2015

One way of reducing the environmental impact of aviation is to improve the efficiency of aircraft operations to reduce fuel burn and emissions. In the current air transportation system, there are many factors that can cause aircraft to be operated away from the environmentally optimal trajectory. This chapter outlines the factors that can impact the environmental efficiency of aircraft operations in the different planning and flight phases. These include decisions made by the airline, pilot and air traffic controller and limitations imposed by airspace design, congestion, and weather. Best practice aircraft operation techniques that may reduce environmental impact are then detailed.
Target Detection and Mission Planning Based on Pigeon‐Inspired Optimization
Authors: Duan Haibin
Published: December 2015

As with manned aircraft flights, mission planning is a critical element in successful mission performance of unmanned aerial vehicles (UAVs). In the simplest case, a vehicle is supposed to fly over a disaster area such as wood fire or a large traffic accident and deliver high‐quality sensor data such as images or videos. This chapter deals with target detection, path planning, and mission assignment for UAVs using a newly proposed optimization method named pigeon‐inspired optimization (PIO). In Section 2, the biological behaviors of pigeons are introduced and the principle of basic PIO is described in detail. The hybrid model of edge potential function (EPF) and simulated annealing pigeon‐inspired optimization algorithm (SAPIO) is proposed to accomplish the target detection task for UAVs at low altitude in Section 3. We deal with 2D and 3D path planning problem to search out an optimal or a near‐optimal flight path between an initial location and the desired destination in Section 4. In Section 5, PIO is applied to mission assignment problem for multiple UAVs. Our concluding remarks are provided in Section 6.
Trajectory Planning and Guidance
Authors: Isaiah Pantelis , Shima Tal
Published: December 2015

Trajectory planning and guidance are presented as successive steps in the process of solving problems related to the control of autonomous vehicles, with a focus on scenarios in which motion can be assumed to be planar. The exposition of relevant methods and results is structured in a manner that brings to the fore the principle of decomposing a given problem into subproblems whose solutions are analytically and computationally tractable, and can be synthesized to yield control algorithms amenable to real‐time implementation. To this end, widely used kinematic models, for example, the Dubins and Reeds–Shepp vehicles, are presented and analyzed, along with more recent extensions thereof. Such models are useful abstractions, albeit not sufficiently granular to capture the complexities of real‐world vehicles. Therefore, the analysis of the kinematic models is followed by methods for applying guidance laws that allow any vehicle that implements them to track the trajectories generated by means of the kinematic models within some margin of error. Trajectory planning and guidance are established and active research areas that are becoming increasingly interdisciplinary, especially in the context of autonomous systems; the list of references at the end of the chapter is intended as a complement to the necessarily selective choice of material presented herein.