bluuebunny/crossref_metadata_2025_split huggingface dataset:
Upper D region chemical kinetic modeling of LORE relaxation times
Authors: Gordillo‐Vázquez F. J. , Luque A. , Haldoupis C. 
Published: March 2016

AbstractThe recovery times of upper D region electron density elevations, caused by lightning‐induced electromagnetic pulses (EMP), are modeled. The work was motivated from the need to understand a recently identified narrowband VLF perturbation named LOREs, an acronym for LOng Recovery Early VLF events. LOREs associate with long‐living electron density perturbations in the upper D region ionosphere; they are generated by strong EMP radiated from large peak current intensities of ±CG (cloud to ground) lightning discharges, known also to be capable of producing elves. Relaxation model scenarios are considered first for a weak enhancement in electron density and then for a much stronger one caused by an intense lightning EMP acting as an impulsive ionization source. The full nonequilibrium kinetic modeling of the perturbed mesosphere in the 76 to 92 km range during LORE‐occurring conditions predicts that the electron density relaxation time is controlled by electron attachment at lower altitudes, whereas above 79 km attachment is balanced totally by associative electron detachment so that electron loss at these higher altitudes is controlled mainly by electron recombination with hydrated positive clusters H+(H2O)n and secondarily by dissociative recombination with NO+ ions, a process which gradually dominates at altitudes >88 km. The calculated recovery times agree fairly well with LORE observations. In addition, a simplified (quasi‐analytic) model build for the key charged species and chemical reactions is applied, which arrives at similar results with those of the full kinetic model. Finally, the modeled recovery estimates for lower altitudes, that is <79 km, are in good agreement with the observed short recovery times of typical early VLF events, which are known to be associated with sprites.
Dynamic effects of restoring footpoint symmetry on closed magnetic field lines
Authors: Reistad J. P. , Østgaard N. , Tenfjord P. , Laundal K. M. , Snekvik K. , Haaland S. , Milan S. E. , Oksavik K. , Frey H. U. , Grocott A. 
Published: March 2016

AbstractHere we present an event where simultaneous global imaging of the aurora from both hemispheres reveals a large longitudinal shift of the nightside aurora of about 3 h, being the largest relative shift reported on from conjugate auroral imaging. This is interpreted as evidence of closed field lines having very asymmetric footpoints associated with the persistent positive y component of the interplanetary magnetic field before and during the event. At the same time, the Super Dual Auroral Radar Network observes the ionospheric nightside convection throat region in both hemispheres. The radar data indicate faster convection toward the dayside in the dusk cell in the Southern Hemisphere compared to its conjugate region. We interpret this as a signature of a process acting to restore symmetry of the displaced closed magnetic field lines resulting in flux tubes moving faster along the banana cell than the conjugate orange cell. The event is analyzed with emphasis on Birkeland currents (BC) associated with this restoring process, as recently described by Tenfjord et al. (2015). Using data from the Active Magnetosphere and Planetary Electrodynamics Response Experiment (AMPERE) during the same conditions as the presented event, the large‐scale BC pattern associated with the event is presented. It shows the expected influence of the process of restoring symmetry on BCs. We therefore suggest that these observations should be recognized as being a result of the dynamic effects of restoring footpoint symmetry on closed field lines in the nightside.
Characteristics of the near‐surface atmosphere over the Ross Ice Shelf, Antarctica
Authors: Cassano John J. , Nigro Melissa A. , Lazzara Matthew A. 
Published: March 2016

AbstractTwo years of data from a 30 m instrumented tower are used to characterize the near‐surface atmospheric state over the Ross Ice Shelf, Antarctica. Stable stratification dominates the surface layer at this site, occurring 83% of the time. The strongest inversions occur for wind speeds less than 4 m s−1 and the inversion strength decreases rapidly as wind speed increases above 4 m s−1. In summer unstable stratification occurs 50% of the time and unstable conditions are observed in every season. A novel aspect of this work is the use of an artificial neural network pattern identification technique, known as self‐organizing maps, to objectively identify characteristic potential temperature profiles that span the range of profiles present in the 2 year study period. The self‐organizing map clustering technique allows the more than 100,000 observed potential temperature profiles to be represented by just 30 patterns. The pattern‐averaged winds show distinct and physically consistent relationships with the potential temperature profiles. The strongest winds occur for the nearly well mixed but slightly stable patterns and the weakest winds occur for the strongest inversion patterns. The weakest wind shear over the depth of the tower occurs for slightly unstable profiles and the largest wind shear occurs for moderately strong inversions. Pattern‐averaged log wind profiles are consistent with theoretical expectations. The log wind profiles exhibit a kinked profile for the strongest inversion cases indicative of decoupling of the winds between the bottom and top of the tower.
Predictability of the stratospheric polar vortex breakdown: An ensemble reforecast experiment for the splitting event in January 2009
Authors: Noguchi Shunsuke , Mukougawa Hitoshi , Kuroda Yuhji , Mizuta Ryo , Yabu Shoukichi , Yoshimura Hiromasa 
Published: March 2016

AbstractA series of ensemble reforecast experiments is conducted to investigate the predictability and the occurrence mechanism of a stratospheric sudden warming occurred in late January 2009, which is a typical polar vortex splitting event. To fully examine the rapid vortex splitting evolution and predictability variation, ensemble forecasts are carried out every day during January 2009. The vortex splitting event is reliably predicted by forecasts initialized after 6 days prior to the vortex breakup. It is also found that the propagating property of planetary waves within the stratosphere is a key to the successful prediction for the vortex splitting event. Planetary waves incoming from the troposphere are reflected back into the troposphere for failed forecasts, whereas they are absorbed within the stratosphere for succeeded forecasts. Composite analysis reveals the following reflection process of planetary waves for the failed forecast: Upward propagation of planetary wave activity from a tropospheric blocking over Alaska is weaker during initial prediction periods; then, the deceleration of the zonal wind in the upper stratosphere becomes weaker over Europe, which produces a preferable condition for the wave reflection; hence, subsequently incoming wave activity from the troposphere over Europe is reflected back over the Siberia inducing the eastward phase tilt of planetary waves, which shuts down the further upward propagation of planetary waves leading to the vortex splitting. Thus, this study shows that the stratospheric condition would be another important control factor for the occurrence of the vortex splitting event, besides anomalous tropospheric circulations enforcing upward propagation of planetary waves.
The signatures of large‐scale patterns of atmospheric variability in Antarctic surface temperatures
Authors: Marshall Gareth J. , Thompson David W. J. 
Published: March 2016

AbstractWe investigate the impact that the four principal large‐scale patterns of Southern Hemisphere (SH) atmospheric circulation variability have on Antarctic surface air temperature (SAT): (1) the southern baroclinic annular mode (BAM), which is associated with variations in extratropical storm amplitude; (2) the Southern Annular Mode (SAM), associated with latitudinal shifts in the midlatitude jet; and (3) the two Pacific‐South American patterns (PSA1 and PSA2), which are characterized by wave trains originating in the tropical Pacific that extend across the SH extratropics. A key aspect is the use of 35 years of daily observations and reanalysis data, which affords a sufficiently large sample size to assess the signatures of the circulation patterns in both the mean and variability of daily mean SAT anomalies. The BAM exerts the weakest influence on Antarctic SAT, albeit it is still important over select regions. Consistent with previous studies, the SAM is shown to influence SAT across most of the continent throughout the year. The PSA1 also affects SAT across almost all of Antarctica. Regionally, both PSA patterns can exert a greater impact on SAT than the SAM but also have a significantly weaker influence during summer, reflecting the seasonality of the SH response to El Niño–Southern Oscillation. The SAM and PSA patterns have distinct signatures in daily SAT variance that are physically consistent with their signatures in extratropical dynamic variability. The broad‐scale climate linkages identified here provide benchmarks for interpreting the Antarctic climate response to future changes in tropical sea surface temperatures, ozone recovery, and greenhouse gas increases.
P and S wave responses of bacterial biopolymer formation in unconsolidated porous media
Authors: Noh Dong‐Hwa , Ajo‐Franklin Jonathan B. , Kwon Tae‐Hyuk , Muhunthan Balasingam 
Published: March 2016

AbstractThis study investigated the P and S wave responses and permeability reduction during bacterial biopolymer formation in unconsolidated porous media. Column experiments with fine sands, where the model bacteria Leuconostoc mesenteroides were stimulated to produce insoluble biopolymer, were conducted while monitoring changes in permeability and P and S wave responses. The bacterial biopolymer reduced the permeability by more than 1 order of magnitude, occupying ~10% pore volume after 38 days of growth. This substantial reduction was attributed to the bacterial biopolymer with complex internal structures accumulated at pore throats. S wave velocity (VS) increased by more than ~50% during biopolymer accumulation; this indicated that the bacterial biopolymer caused a certain level of stiffening effect on shear modulus of the unconsolidated sediment matrix at low confining stress conditions. Whereas replacing pore water by insoluble biopolymer was observed to cause minimal changes in P wave velocity (VP) due to the low elastic moduli of insoluble biopolymer. The spectral ratio analyses revealed that the biopolymer formation caused a ~50–80% increase in P wave attenuation (1/QP) at the both ultrasonic and subultrasonic frequency ranges, at hundreds of kHz and tens of kHz, respectively, and a ~50–60% increase in S wave attenuation (1/QS) in the frequency band of several kHz. Our results reveal that in situ biopolymer formation and the resulting permeability reduction can be effectively monitored by using P and S wave attenuation in the ultrasonic and subultrasonic frequency ranges. This suggests that field monitoring using seismic logging techniques, including time‐lapse dipole sonic logging, may be possible.
Extracting ocean‐generated tidal magnetic signals from Swarm data through satellite gradiometry
Authors: Sabaka Terence J. , Tyler Robert H. , Olsen Nils 
Published: March 2016

AbstractOcean‐generated magnetic field models of the Principal Lunar, M2, and the Larger Lunar elliptic, N2, semidiurnal tidal constituents were estimated through a “Comprehensive Inversion” of the first 20.5 months of magnetic measurements from European Space Agency's (ESA) Swarm satellite constellation mission. While the constellation provides important north‐south along‐track gradiometry information, it is the unique low‐spacecraft pair that allows for east‐west cross‐track gradiometry. This latter type is crucial in delivering an M2 estimate of similar quality with that derived from over 10 years of CHAMP satellite data but over a shorter interval, at higher altitude, and during more magnetically disturbed conditions. Recovered N2 contains nonoceanic signal but is highly correlated with theoretical models in regions of maximum oceanic amplitude. Thus, satellite magnetic gradiometry may eventually enable the monitoring of ocean electrodynamic properties at temporal resolutions of 1 to 2 years, which may have important implications for the inference of ocean temperature and salinity.
Ocean waves across the Arctic: Attenuation due to dissipation dominates over scattering for periods longer than 19 s
Authors: Ardhuin Fabrice , Sutherland Peter , Doble Martin , Wadhams Peter 
Published: March 2016

AbstractThe poorly understood attenuation of surface waves in sea ice is generally attributed to the combination of scattering and dissipation. Scattering and dissipation have very different effects on the directional and temporal distribution of wave energy, making it possible to better understand their relative importance by analysis of swell directional spreading and arrival times. Here we compare results of a spectral wave model—using adjustable scattering and dissipation attenuation formulations—with wave measurements far inside the ice pack. In this case, scattering plays a negligible role in the attenuation of long swells. Specifically, scattering‐dominated attenuation would produce directional wave spectra much broader than the ones recorded, and swell events arriving later and lasting much longer than observed. Details of the dissipation process remain uncertain. Average dissipation rates are consistent with creep effects but are 12 times those expected for a laminar boundary layer under a smooth solid ice plate.
Simultaneous observations of atmospheric tides from combined in situ and remote observations at Mars from the MAVEN spacecraft
Authors: England Scott L. , Liu Guiping , Withers Paul , Yiğit Erdal , Lo Daniel , Jain Sonal , Schneider Nicholas M. , Deighan Justin , McClintock William E. , Mahaffy Paul R. , Elrod Meredith , Benna Mehdi , Jakosky Bruce M. 
Published: March 2016

AbstractWe report the observations of longitudinal variations in the Martian thermosphere associated with nonmigrating tides. Using the Neutral Gas Ion Mass Spectrometer (NGIMS) and the Imaging Ultraviolet Spectrograph (IUVS) on NASA's Mars Atmosphere and Volatile EvolutioN Mission (MAVEN) spacecraft, this study presents the first combined analysis of in situ and remote observations of atmospheric tides at Mars for overlapping volumes, local times, and overlapping date ranges. From the IUVS observations, we determine the altitude and latitudinal variation of the amplitude of the nonmigrating tidal signatures, which is combined with the NGIMS, providing information on the compositional impact of these waves. Both the observations of airglow from IUVS and the CO2 density observations from NGIMS reveal a strong wave number 2 signature in a fixed local time frame. The IUVS observations reveal a strong latitudinal dependence in the amplitude of the wave number 2 signature. Combining this with the accurate CO2 density observations from NGIMS, this would suggest that the CO2 density variation is as high as 27% at 0–10° latitude. The IUVS observations reveal little altitudinal dependence in the amplitude of the wave number 2 signature, varying by only 20% from 160 to 200 km. Observations of five different species with NGIMS show that the amplitude of the wave number 2 signature varies in proportion to the inverse of the species scale height, giving rise to variation in composition as a function of longitude. The analysis and discussion here provide a roadmap for further analysis as additional coincident data from these two instruments become available.
Racial‐ethnic Identity in Context: Examining Mediation of Neighborhood Factors on Children's Academic Adjustment
Authors: Witherspoon Dawn P. , Daniels Lisa L. , Mason Amber E. , Smith Emilie Phillips 
Published: March 2016

AbstractResearch consistently shows that neighborhood socio‐demographic characteristics and residents’ neighborhood perceptions matter for youth well‐being, including a positive sense of racial‐ethnic identity. Although elementary‐school children are likely in the earlier phases of identity formation, the authors examined whether objective and subjective neighborhood characteristics are related to their racial‐ethnic identity and, in turn, their academic adjustment. A diverse sample (30.4% African American, 35.2% White, 12.3% Latino, & 22.0% Other) of 227 children in Grades 2 through 5 were surveyed in afterschool programs. Bivariate correlations showed that youth living in disadvantaged neighborhoods reported more barriers due to their race‐ethnicity, but these barriers were not related to their sense of academic efficacy. Residing in a disadvantaged neighborhood was unrelated to youth's academic self‐efficacy. However, path analyses showed that positive neighborhood perceptions were associated with a stronger sense of race‐ethnicity (i.e., affirmation and belonging), which was in turn related to greater academic efficacy. These results suggest that neighborhood connection provides a source of affirmation and value for young children, helping them to understand who they are as part of a racial‐ethnic group and helping to foster a sense of future achievement opportunities. This study provides additional evidence that along with other important proximal contexts (e.g., family, school), young children's neighborhood context is important for development. Results are discussed to highlight environmental influences on young children's awareness of race‐ethnicity and the implications of the combined impact of neighborhood and racial‐ethnic identity on psychosocial adjustment.
Analysis of consumption of medical resources in terms of intensive care unit/hospital stay and severity using Japan Trauma Data Bank
Authors: Oda Jun 
Published: March 2016

AimWe analyzed the length of intensive care unit or hospital stay of trauma patients to assess the consumption of medical resources using the Japan Trauma Data Bank.MethodsWe classified 60,580 cases registered between 2004 and 2010 in the Japan Trauma Data Bank by hospital ward on emergency admission.ResultsA total of 9,564 intensive care patients could be moved to the general ward before hospital transfer or discharge; 6,217 cases were transferred to another hospital and 9,444 cases were discharged directly from the intensive care unit. The length of intensive care unit or hospital stay correlated with the injury severity score. There were 5,856 patients (68%) from the non‐survivors who died within 3 days of admission.ConclusionBased on the Japan Trauma Data Bank data for many trauma patients, there are numerous cases of long‐term stay ≥15 days in intensive care in patients who could not be transferred to a general ward and who consumed the medical resources in the critical care department.
Self‐inflicted injuries are an important cause of penetrating traumatic injuries in Japan
Authors: Izawa Yoshimitsu , Suzukawa Masayuki , Lefor Alan K. 
Published: March 2016

AimJapan has a low crime rate, but a high suicide rate. The aim of this study is to review the causes of penetrating traumatic injuries in a tertiary care emergency center in Japan.MethodsWe retrospectively reviewed all admissions for traumatic injuries over a 3‐year period, and calculated the proportion of patients with penetrating traumatic injuries. Weapon used, age, gender, Injury Severity Score, cause of injury, and site of injury in all patients with penetrating injuries were reviewed. The proportion of patients with penetrating injuries among patients with all types of traumatic injuries requiring surgical intervention was calculated.ResultsOf 1,321 patients admitted over 3 years, 65 patients (5%) suffered from penetrating injuries. Most were stab wounds, with only one gunshot (2%). The most common site of injury was an extremity (48%). The most common cause of penetrating injury was self‐inflicted (38%). The abdomen is the most common site injured among self‐inflicted injuries. Of patients with all types of traumatic injuries requiring surgical intervention, penetrating injuries accounted for 23%.ConclusionPenetrating injuries represent 23% of all patients with traumatic injuries who required surgical intervention. Self‐inflicted penetrating injuries were most common, supporting the need for preventive services. Acute care surgeons must be familiar with the surgical management of penetrating traumatic injuries, even in a country with a low crime rate.
Second modification of a polyamide membrane surface
Authors: Akbari Ahmad , Mohtasham Khani Saeedeh , Mojallali Rostami Seyed Majid 
Published: March 2016

ABSTRACTThe aim of this study was to develop the water flux and antifouling properties of a polyamide (PA) nanofiltration membrane. A nascent PA membrane was prepared with an interfacial polymerization technique and modified with 2,5‐diaminobenzene sulfonic acid (2,5‐DABSA) as a second modification. The effects of the 2,5‐DABSA monomer concentration and the modification time on the membrane performance were investigated. The chemical structure, morphology, roughness, hydrophilicity, molecular weight cutoff, and antifouling properties of the membranes were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy, atomic force spectroscopy, contact angle measurement, poly(ethylene glycol) tracers, and cetyl trimethyl ammonium bromide filtration, respectively. The PA membrane with optimized performance was shown to have a greater than 44% higher water permeate flux with a change in the salt rejection in the order RNa2SO4 > RCaCl2 > RNaCl to RNa2SO4 > RNaCl > RCaCl2. The improvement of the hydrophilicity led to excellent antifouling properties in the new PA membranes and illustrated a promising and simple method for the fabrication of high‐performance PA membranes. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43583.
Radiometric dates are a robust proxy for long‐term demographic change: A comment on Attenbrow and Hiscock (2015)
Authors: WILLIAMS ALAN N. , ULM SEAN 
Published: March 2016

ABSTRACTAttenbrow and Hiscock (2015) raise a series of concerns about the use of radiocarbon dates as data (sum probability distributions), including sample selection, taphonomic bias, and the relationship of charcoal and radiocarbon data to human activity. We show that these concerns have been widely acknowledged and addressed in the literature. We advocate the considered use of dates as data approaches as a heuristic tool for broad regional‐ and continental‐scale questions, used in conjunction with other archaeological proxies, and within the constraints of documented and well‐known methodological limitations.