bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Centennial Gleissberg Cycle and its association with extended minima
Authors: Feynman J. , Ruzmaikin A. 
Published: August 2014

AbstractThe recent extended minimum of solar and geomagnetic variability (XSM) mirrors the XSMs in the nineteenth and twentieth centuries: 1810–1830 and 1900–1910. Such extended minima also were evident in aurorae reported from 450 A.D. to 1450 A.D. This paper argues that these minima are consistent with minima of the Centennial Gleissberg Cycles (CGCs), a 90–100 year variation observed on the Sun, in the solar wind, at the Earth, and throughout the heliosphere. The occurrence of the recent XSM is consistent with the existence of the CGC as a quasiperiodic variation of the solar dynamo. Evidence of CGCs is provided by the multicentury sunspot record, by the almost 150 year record of indexes of geomagnetic activity (1868 to present), by 1000 years of observations of aurorae (from 450 to 1450 A.D.) and millennial records of radionuclides in ice cores. The aa index of geomagnetic activity carries information about the two components of the solar magnetic field (toroidal and poloidal), one driven by flares and coronal mass ejections (related to the toroidal field) and the other driven by corotating interaction regions in the solar wind (related to the poloidal field). These two components systematically vary in their intensity and relative phase giving us information about centennial changes of the sources of solar dynamo during the recent CGC over the last century. The dipole and quadrupole modes of the solar magnetic field changed in relative amplitude and phase; the quadrupole mode became more important as the XSM was approached. Some implications for the solar dynamo theory are discussed.
The force‐free configuration of flux ropes in geomagnetotail: Cluster observations
Authors: Yang Y. Y. , Shen C. , Zhang Y. C. , Rong Z. J. , Li X. , Dunlop M. , Ma Y. H. , Liu Z. X. , Carr C. M. , Rème H. 
Published: August 2014

AbstractUnambiguous knowledge of magnetic field structure and the electric current distribution is critical for understanding the origin, evolution, and related dynamic properties of magnetic flux ropes (MFRs). In this paper, a survey of 13 MFRs in the Earth's magnetotail are conducted by Cluster multipoint analysis, so that their force‐free feature, i.e., the kind of magnetic field structure satisfying J × B = 0, can be probed directly. It is showed that the selected flux ropes with the bipolar signature of the south‐north magnetic field component generally lie near the equatorial plane, as expected, and that the magnetic field gradient is rather weak near the axis center, where the curvature radius is large. The current density (up to several tens of nA/m2) reaches their maximum values as the center is approached. It is found that the stronger the current density, the smaller the angles between the magnetic field and current in MFRs. The direct observations show that only quasi force‐free structure is observed, and it tends to appear in the low plasma beta regime (in agreement with the theoretic results). The quasi force‐free region is generally found to be embedded in the central portion of the MFRs, where the current is approximately field aligned and proportional to the strength of core field. It is shown that ~60% of surveyed MFRs can be globally approximated as force free. The force‐free factor α is found to be nonconstantly varied through the quasi force‐free MFR, suggesting that the force‐free structure is nonlinear.
Feedbacks between ice cover, ocean stratification, and heat content in Ryder Bay, western Antarctic Peninsula
Authors: Venables Hugh J. , Meredith Michael P. 
Published: August 2014

AbstractA multiyear, all‐season time series of water column physical properties and sea ice conditions in Ryder Bay, at the western Antarctic Peninsula (WAP), is used to assess the effects on the ocean of varying ice cover. Reduced ice cover leads to increased mixing and heat loss in the winter. The reduction in stratification persists into the following summer, preconditioning the water column to a greater vertical extent of surface‐driven mixing. This leads to an increased amount of heat from insolation being mixed down, affecting approximately the top 100 m. The increased heat uptake in summer exceeds the heat lost the preceding winter, giving the initially counter‐intuitive effect that enhanced winter cooling generates warmer temperatures in the following summer and autumn. This process is therefore a positive feedback on sea ice, as reduced sea ice leads to increased heat content in the ocean the following autumn. It also causes increased winter atmospheric temperatures due to the increased winter heat loss from the ocean. In the deeper part of the water column, heat and carbon stored in the Circumpolar Deep Water (CDW) layer are released by deep mixing events. At these depths, conditions are restored by advection and vertical mixing on multiyear time scales. In recent years, stronger deep mixing events in winter have led to a persistent reduction in CDW temperatures at the study site. Ocean glider data demonstrate the representativeness of these results across the wider region of Marguerite Bay, within which Ryder Bay is situated.
Decreased monsoon precipitation in the Northern Hemisphere due to anthropogenic aerosols
Authors: Polson D. , Bollasina M. , Hegerl G. C. , Wilcox L. J. 
Published: August 2014

AbstractThe Northern Hemisphere monsoons are an integral component of Earth's hydrological cycle and affect the lives of billions of people. Observed precipitation in the monsoon regions underwent substantial changes during the second half of the twentieth century, with drying from the 1950s to mid‐1980s and increasing precipitation in recent decades. Modeling studies suggest that anthropogenic aerosols have been a key factor driving changes in tropical and monsoon precipitation. Here we apply detection and attribution methods to determine whether observed changes are driven by human influences using fingerprints of individual forcings (i.e., greenhouse gas, anthropogenic aerosol, and natural) derived from climate models. The results show that the observed changes can only be explained when including the influence of anthropogenic aerosols, even after accounting for internal climate variability. Anthropogenic aerosol, not greenhouse gas or natural forcing, has been the dominant influence on Northern Hemisphere monsoon precipitation over the second half of the twentieth century.
The solar type II radio bursts of 7 March 2012: Detailed simulation analyses
Authors: Schmidt J. M. , Cairns Iver H. , Lobzin V. V. 
Published: August 2014

AbstractType II solar radio bursts are often indicators for impending space weather events at Earth. They are consequences of shock waves driven by coronal mass ejections (CMEs) that move outward from the Sun. We simulate such type II radio bursts by combining elaborate three‐dimensional (3‐D) magnetohydrodynamic (MHD) predictions of realistic CMEs near the Sun with an analytic kinetic radiation theory developed recently. The simulation approach includes the reconstruction of initial solar magnetic fields, the dimensioning of the initial flux rope of the CME with STEREO spacecraft data, and the launch of the CME into an empirical data‐driven corona and solar wind. In this paper, we simulate a complicated double CME event (a very fast CME followed by a slower CME without interaction) and the related coronal and interplanetary type II radio bursts that occurred on 7 March 2012. We extend our previous work to show harmonic and interplanetary emission as well as the simulation's surprising ability (for these events at least) for predicting emission for two closely spaced CMEs leaving the same active region. We demonstrate that the theory predicts well the observed fundamental and harmonic emission from ∼20 MHz to 50 kHz or from the high corona to near 1 AU. Specifically, the theory predicts flux, frequency, and time variations that are consistent with the presence or absence of observed type II emissions when interfering emissions are absent and are not inconsistent with observations when interfering type III bursts are present. The predicted and observed type II emission is predominantly fundamental for these two events. Harmonic emission occurs for the second CME only for a short time interval, when an extended shock has developed that can drive flank emission. The coronal and interplanetary emission follow closely hyperbolic lines in frequency‐time space, consisting of a succession of islands of emission with varying intensity. The islands develop due to competition between the shock moving through varying coronal and solar wind magnetic field structures (e.g., loops and streamers), growth of the driven radio source due to the spherical expansion of the shock, and movement of the active radio sources from the shock's nose to its flanks.
Micrometeoroid impact charge yield for common spacecraft materials
Authors: Collette A. , Grün E. , Malaspina D. , Sternovsky Z. 
Published: August 2014

AbstractThe impact ionization charge yield is experimentally measured from four common materials used in space and specifically on the two STEREO spacecraft (germanium‐coated black Kapton, beryllium copper, multilayer insulation, and solar cells). Cosmic dust particle impacts on spacecraft have been detected by electric field and plasma and radio wave instruments. The accurate interpretation of these signals is complicated by many factors, including the details of the spacecraft antenna system, the local spacecraft plasma environment, and our understanding of the physics of the impact process. The most basic quantity, the amount of charge liberated upon impact, is generally considered poorly constrained and is suspected to depend on the target material. Here we show that for common materials used on spacecraft this variability is small for impacts around 10 km/s, and the impact charge yield can be approximated by 80 fC for a 1 pg projectile. At higher speeds (∼50 km/s), variation of up to a factor of 5 is observed. The measured yields in the 10–50 km/s range are compared to measurements and predictions from the literature and are found to be lower than predicted by at least a factor of 12 at 10 km/s and at least a factor of 1.7 at 50 km/s. Impact charge is also found to depend on angle of incidence; the data suggest a maximum at 45°.
A coordinated investigation of the gravity wave breaking and the associated dynamical instability by a Na lidar and an Advanced Mesosphere Temperature Mapper over Logan, UT (41.7°N, 111.8°W)
Authors: Cai Xuguang , Yuan Tao , Zhao Yucheng , Pautet Pierre‐Dominique , Taylor Mike J. , Pendleton W. R. 
Published: August 2014

AbstractThe impacts of gravity wave (GW) on the thermal and dynamic characteristics within the mesosphere/lower thermosphere, especially on the atmospheric instabilities, are still not fully understood. In this paper, we conduct a comprehensive and detailed investigation on one GW breaking event during a collaborative campaign between the Utah State University Na lidar and the Advanced Mesospheric Temperature Mapper (AMTM) on 9 September 2012. The AMTM provides direct evidence of the GW breaking as well as the horizontal parameters of the GWs involved, while the Na lidar's full diurnal cycle observations are utilized to uncover the roles of tide and GWs in generating a dynamical instability layer. By studying the changes of the OH layer peak altitude, we located the wave breaking altitude as well as the significance of a 2 h wave that are essential to this instability formation. By reconstructing the mean fields, tidal and GW variations during the wave breaking event, we find that the large‐amplitude GWs significantly changed the Brunt–Vaisala frequency square and the horizontal wind shear when superimposed on the tidal wind, producing a transient dynamic unstable region between 84 km and 87 km around 11:00 UT that caused a subsequent small‐scale GW breaking.
Numerical modeling of the global changes to the thermosphere and ionosphere from the dissipation of gravity waves from deep convection
Authors: Vadas S. L. , Liu H.‐L. , Lieberman R. S. 
Published: August 2014

AbstractDuring the minimum of solar cycles 23–24, the Sun was extremely quiet; however, tropospheric deep convection was strong and active. In this paper, we model the gravity waves (GWs) excited by deep convective plumes globally during 15–27 June in 2009 and in 2000 (previous solar maximum). We ray trace the GWs into the thermosphere and calculate the body force/heatings which result where they dissipate. We input these force/heatings into a global dynamical model and study the neutral and plasma changes that result. The body forces induce horizontal wind () and temperature (T′) perturbations, while the heatings primarily induce T′. We find that the forces create much larger T′ than the heatings. consists of clockwise and counterclockwise circulations and “jet”‐like winds that are highly correlated with deep convection, with ∼50–200m/s. and T′ are much larger during 2009 than 2000. decreases slightly (significantly) with altitude from z∼150 to 400 km during 2009 (2000). T′ perturbations at z=350km primarily propagate westward at ∼460 m/s, consistent with migrating tides. It was found that planetary‐scale diurnal and semidiurnal tides are generated in situ in the thermosphere, with amplitudes ∼10–40m/s at z=250 km. The largest‐amplitude in situ tides are DW1, D0, DW2, SW2, SW3, and SW5. Smaller‐amplitude in situ tides are S0, SE2, and SW3. Total electron content (TEC′) perturbations of 1–2.5 (2–3.5) total electron content units (TECU, where 1 TECU = 1016 el m−2) during 2009 (2000) are created in the upper atmosphere above nearby regions of deep tropical convection. For a given local time (LT), there are 2 to 3 TEC′ peaks in longitude around the Earth.
Infrasonic interferometry applied to microbaroms observed at the Large Aperture Infrasound Array in the Netherlands
Authors: Fricke J. T. , Evers L. G. , Smets P. S. M. , Wapenaar K. , Simons D. G. 
Published: August 2014

AbstractWe present the results of infrasonic interferometry applied to microbaroms, obtained from ambient noise. For this purpose the “Large Aperture Infrasound Array” (LAIA) was used, which has been installed in the Netherlands. Preprocessing appeared to be an essential step in enhancing the microbarom signals from ambient noise that strongly influences the results of the interferometry. Both the state of the atmosphere and the noise characteristics are taken into account to assess the strength of the cross correlation. The delay time of the microbaroms between two stations is determined through cross correlating the recordings. By calculating the cross correlations between all 55 station pairs of LAIA, we are able to find the delay time of microbaroms up to a interstation distance of 40.6 km. Using the strength of the cross correlations, we are able to show that the coherence of the microbaroms along the direction of arrival is higher than orthogonal to it. A comparison of the atmospheric state, with a cross correlation, over a period of 10 days, reveals that the infrasound propagation over the array is correlated with the tropospheric temperature and wind. Based on the cross correlations between the three closest stations, we are able to passively estimate the effective sound speed and the wind speed as a function of time.
Study on fracture behavior of PLLA transcrystallization: Effect of crystalline morphology
Authors: Wen Tao , Zhang Xiuqin , Xiong Zujiang , de Vos Sicco , Wang Ruyin , Wang Fosong , Wang Dujin 
Published: August 2014

ABSTRACTIn the present work, the fracture behavior of transcrystallization (TC) of poly(l‐lactic acid) (PLLA) in thin film and the dependence of mechanical properties on the morphology of TC have been studied. The nucleation density of TC was merely determined by the annealing temperatures of the fibers which used for inducing nucleation, and the crystallization temperature and time of the samples were completely identical. By using in situ polarized optical microscopy, the fracture process of TCs was characterized. For the TC with high nucleating density (TC‐H), lots of cracks were generated from the TC bulk during fracture. But only few cracks were observed on the TC with low nucleation density (TC‐L), and the final fracture of TC‐L always occurred in the junctions of crystal segments. Compared to the samples which do not contain TC, the fracture strength was enhanced by 8.1% because of the presence of TC‐H. On the contrary, the presence of TC‐L can reduce the fracture strength of the samples. The fracture surfaces of TC were characterized by scanning electron microscope. It was observed that the fracture surface of TC‐H exhibited obvious fibrillation and cavitation, but the fracture surface of TC‐L was smooth and featureless. The possible fracture mechanism for two TCs was discussed in view of their intrinsic crystal organizations. © 2014 The Authors Journal of Applied Polymer Science Published by Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41273.
Efficient solution‐processed double‐layer red OLEDs based on a new europium complex with a carbazole group
Authors: Liu Jian , Miao Jing‐Sheng , Wu Hong‐Bin 
Published: August 2014

AbstractA new europium complex EuL3(Phen) was used as guest dopant, and a blend of Polyvinylcarbazole and 2‐(biphenyl‐4‐yl)‐5‐(4‐tert‐butylphenyl)‐1,3,4‐oxadiazole (PVK and PBD) as host matrix. Efficient red organic light‐emitting devices (OLEDs) with double‐layer structures were manufactured via a solution‐processed technique. The guest‐doped levels were 1, 3 and 5 wt% relative to the blend mass, respectively. For the 1 wt% doping‐level device, the luminous efficiency and luminance were up to 2.96 cd/A and 635.78 cd/m2 with emissions from both EuL3(Phen) and from the host; for the 3 wt% doping‐level device, the maximum luminous efficiency and luminance were 1.01 cd/A and 370.91 cd/m2 for the single emission from EuL3(Phen) only. Copyright © 2014 John Wiley & Sons, Ltd.
Impact of omission of surgery on survival of older patients with breast cancer
Authors: de Glas N A , Jonker J M , Bastiaannet E , de Craen A J M , van de Velde C J H , Siesling S , Liefers G-J , Portielje J E A , Hamaker M E 
Published: August 2014

Abstract

Background
Older patients with breast cancer are often not treated in accordance with guidelines. With the emergence of endocrine therapy, omission of surgery can be considered in some patients. The aim of this population-based study was to investigate time trends in surgical treatment between 1995 and 2011, and to evaluate the effects of omitting surgery on overall and relative survival in older patients with resectable breast cancer.

Methods
Patients aged 75 years and older with stage I–III breast cancer diagnosed between 1995 and 2011 were selected from the Netherlands Cancer Registry. Time trends of all treatment modalities were evaluated using linear regression models. Changes in overall survival were calculated by Cox regression. Relative survival was calculated using the Ederer II method.

Results
Overall, 26 292 patients were included. The proportion of patients receiving surgical treatment decreased significantly, from 90·8 per cent in 1995 to 69·9 per cent in 2011 (P &lt; 0·001). Multivariable analysis showed that overall survival did not change over time (hazard ratio 1·00 (95 per cent confidence interval (c.i.) 0·99 to 1·00) per year); nor did relative survival (relative excess risk 1·00 (0·98 to 1·02) per year).

Conclusion
Omission of surgery has become more common in older patients with breast cancer during the past 15 years in the Netherlands, but this has not altered overall or relative survival.
Aspiration cytology of mammary analogue secretory carcinoma of the salivary gland
Authors: Jung Min Jung , Kim Sang Yoon , Nam Soon Yuhl , Roh Jong‐Lyel , Choi Seung‐Ho , Lee Jeong Hyun , Baek Jung Hwan , Cho Kyung‐Ja 
Published: August 2014

BackgroundAspiration cytologic findings of mammary analogue secretory carcinoma (MASC), a newly established salivary gland neoplasm defined by a t(12;15)(p13;q25) ETV6‐NTRK3 translocation, are not fully characterized to date. We report cytologic descriptions of nine cases of molecularly confirmed MASC, including two with unusual findings.MethodsAspiration smears from nine MASCs of the salivary glands were retrospectively reviewed and analyzed according to the cellular and structural features of the corresponding surgical specimens.ResultsAspiration smears of MASC generally reflected the histologic diversity of the tumors. Among usual histologic findings, a micropapillary pattern was associated with a predominance of vacuolated individual cells on aspiration smears, a papillary‐cystic pattern with a predominance of thin branching papillary structures, and a microcystic pattern with a predominance of irregular sheets of eosinophilic cells. There were two unusual cases, one with three‐dimensional groups of high‐grade atypical cells, and one with epithelial clusters floating in a notably mucinous background. These cases represented MASC with high‐grade transformation and MASC with cystadenocarcinoma‐like features, respectively. The secretory activity of MASC was not prominent in the aspiration specimens.ConclusionsAlthough unusual cases were present, most MASC cases showed characteristic cytologic findings, which could aid the cytologic diagnosis of MASC. And knowledge of the histologic spectrum of MASC, including high‐grade transformation, could be valuable for cytological differential diagnoses of salivary gland tumors, and the management of patients with MASC. Diagn. Cytopathol. 2015;43:287–293. © 2014 Wiley Periodicals, Inc.
Infant perceptual development for faces and spoken words: An integrated approach
Authors: Watson Tamara L. , Robbins Rachel A. , Best Catherine T. 
Published: August 2014

ABSTRACTThere are obvious differences between recognizing faces and recognizing spoken words or phonemes that might suggest development of each capability requires different skills. Recognizing faces and perceiving spoken language, however, are in key senses extremely similar endeavors. Both perceptual processes are based on richly variable, yet highly structured input from which the perceiver needs to extract categorically meaningful information. This similarity could be reflected in the perceptual narrowing that occurs within the first year of life in both domains. We take the position that the perceptual and neurocognitive processes by which face and speech recognition develop are based on a set of common principles. One common principle is the importance of systematic variability in the input as a source ofinformationrather thannoise. Experience of this variability leads to perceptual tuning to the critical properties that define individual faces or spoken words versus their membership in larger groupings of people and their language communities. We argue that parallels can be drawn directly between the principles responsible for the development of face and spoken language perception. © 2014 The Authors.Dev PsychobiolPublished by Wiley Periodicals, Inc. Dev Psychobiol 56: 1454–1481, 2014.