bluuebunny/crossref_metadata_2025_split huggingface dataset:
To jump or not to jump: Mule deer and white‐tailed deer fence crossing decisions
Authors: Burkholder Emily N. , Jakes Andrew F. , Jones Paul F. , Hebblewhite Mark , Bishop Chad J. 
Published: August 2018

ABSTRACTModified fencing structures have been recommended with the intention of enhancing ungulate movement. Ungulates such as mule deer (Odocoileus hemionus) and white‐tailed deer (O. virginianus) typically negotiate fences by jumping over them. We examined 2 fine‐scale fence crossing decisions to determine factors influencing 1) crossing success and 2) the mode of crossing by 2 sympatric deer species. From 2010 to 2016, we used remote cameras along fence lines in 2 study areas—Canadian Forces Base Suffield in southeastern Alberta, Canada, and The Nature Conservancy's Matador Ranch in north‐central Montana, USA—that captured images of deer–fence interactions before and after fence modifications were installed. We used logistic regression to model the probability of deer successfully crossing a fence and mode of crossing (jumping over vs. crawling under) based on fence characteristics and demographic factors. We documented 486 crossing attempts, of which 313 were successful (64.4%), indicating that pasture fences acted as a semipermeable barrier to deer. Of these 313 successful attempts, 152 crawled under the fence (48.6%) as opposed to jumping over it. We documented behavioral differences in mode of crossing between species when successfully crossing a fence. Results indicate that deer are selecting known crossing sites at broad scales as places to negotiate fences, and when assessing finer scale decisions at these sites, white‐tailed deer seemed to acclimate better than mule deer to our imposed changes (switched from crawling under to jumping over the fence). Though sample size was low in terms of use at modified fence sites, we recommend visually inconspicuous modifications (such as clips to increase the bottom wire height as opposed to goat‐bars) when implementing pasture fencing that was friendlier for deer. We also recommend modifications be implemented strategically; placement of modifications may be just as important to consider as the modification type. © 2018 The Wildlife Society.
Optimization of InP DHBT stacked-transistors for millimeter-wave power amplifiers
Authors: Squartecchia Michele , Johansen Tom K. , Dupuy Jean-Yves , Midili Virginio , Nodjiadjim Virginie , Riet Muriel , Konczykowska Agnieszka 
Published: August 2018

AbstractIn this paper, we report the analysis, design, and implementation of stacked transistors for power amplifiers realized on InP Double Heterojunction Bipolar Transistors (DHBTs) technology. A theoretical analysis based on the interstage matching between all the single transistors has been developed starting from the small-signal equivalent circuit. The analysis has been extended by including large-signal effects and layout-related limitations. An evaluation of the maximum number of transistors for positive incremental power and gain is also carried out. To validate the analysis, E-band three- and four-stacked InP DHBT matched power cells have been realized for the first time as monolithic microwave integrated circuits (MMICs). For the three-stacked transistor, a small-signal gain of 8.3 dB, a saturated output power of 15 dBm, and a peak power added efficiency (PAE) of 5.2% have been obtained at 81 GHz. At the same frequency, the four-stacked transistor achieves a small-signal gain of 11.5 dB, a saturated output power of 14.9 dBm and a peak PAE of 3.8%. A four-way combined three-stacked MMIC power amplifier has been implemented as well. It exhibits a linear gain of 8.1 dB, a saturated output power higher than 18 dBm, and a PAE higher than 3% at 84 GHz.
Tidal Flow Asymmetry Owing to Inertia and Waves on an Unstratified, Shallow Ebb Shoal
Authors: Wargula Anna , Raubenheimer Britt , Elgar Steve , Chen Jia‐Lin , Shi Fengyan , Traykovski Peter 
Published: August 2018

AbstractObservations of water levels, waves, currents, and bathymetry collected for a month at an unstratified tidal inlet with a shallow (1 to 2 m deep) ebb shoal are used to evaluate the asymmetry in flows and dynamics owing to inertia and waves. Along‐channel currents ranged from −1.5 to 0.6 m/s (positive inland) inside the main (3 to 5 m deep) channel crossing the ebb shoal. Net discharge is negligible, and ebb dominance of the channel flows is owing to inflow and outflow asymmetries near the inlet mouth. Offshore wave heights ranged from 0.5 to 2.5 m. During moderate to large wave events (offshore significant wave heights >1.2 m), wave forcing enhanced onshore mass flux near the shoal edge and inside the inlet, leading to reduced ebb flow dominance. Momentum balances estimated with the water depths, currents, and waves simulated with a quasi 3‐D numerical model reproduce the momentum balances estimated from the observations reasonably well. Both observations and simulations suggest that ebb‐dominant bottom stresses are balanced by the ebb‐dominant pressure gradient and the tidally asymmetric inertia, which is a sink (source) of momentum on flood (ebb). Simulations with and without waves suggest that waves drive local and nonlocal changes in the water levels and flows. Specifically, breaking waves at the offshore edge of the ebb shoal induce setup and partially block the ebb jet (local effects), which leads to a more onshore‐directed mass flux, changes to the advection across the ebb shoal, and increased water levels inside the inlet mouth (nonlocal effects).
Annual and Semiannual Cycles of Diurnal Warming of Sea Surface Temperature in the South China Sea
Authors: Yan Yunwei , Wang Guihua , Chen Changlin , Ling Zheng 
Published: August 2018

AbstractBased on the SeaFlux data set, an empirical parameterization, and a one‐dimensional ocean mixed‐layer model, the annual and semiannual cycles of diurnal warming of sea surface temperature (dSST) in the South China Sea (SCS) are examined. The amplitude of the annual cycle is greater than 0.1 °C, and the annual cycle reaches its maxima in April/May/June in most areas of the SCS, while the amplitude of the semiannual cycle of dSST increases from north to south with the month of its maxima changing from February to March along a northwest‐southeast axis. Relative to the amplitude of the annual cycle of dSST, the semiannual cycle is of much smaller amplitude north of 17°N, but of comparable or larger amplitude south of 17°N. The annual (semiannual) cycle of wind speed is the most important factor for the annual (semiannual) cycle of dSST. The annual (semiannual) cycle of wind speed drives the annual (semiannual) cycle of dSST primarily by influencing oceanic vertical turbulent mixing. Aside from these basin‐scale features, the dSST annual and semiannual cycles demonstrate robust mesoscale features in the lees of hills/islands as a result of sheltering from the monsoon.
Nighttime Mesospheric/Lower Thermospheric Tropical Ozone Response to the 27‐Day Solar Rotational Cycle: ENVISAT‐GOMOS Satellite Observations Versus HAMMONIA Idealized Chemistry‐Climate Model Simulations
Authors: Thiéblemont R. , Bekki S. , Marchand M. , Bossay S. , Schmidt H. , Meftah M. , Hauchecorne A. 
Published: August 2018

AbstractGlobal Ozone Monitoring by Occultation of Stars (GOMOS) satellite data are analyzed to estimate the first observation‐based nighttime (22:00 median local time) ozone response to the 27‐day solar rotational cycle in the tropical mesosphere/lower thermosphere (50–110 km altitude). The ozone response to solar rotational variability is derived from linear correlation and regressions using Lyman‐α line (121.6 nm) as solar index that varies by about 10–15% over solar rotational cycles. In the lower mesosphere (50–70 km), the GOMOS ozone is found to be correlated with the solar fluctuations and exhibits a sensitivity of ~0.1 (expressed in percent change of ozone for 1% change in Lyman‐α). In the upper mesosphere/lower thermosphere (above 80 km), ozone variations become anticorrelated with solar rotational variations. In this region, the vertical profile of ozone sensitivity to the 27‐day solar cycle exhibits a maximum of 1.8 at 81 km, a minimum of 0.3 at 100 km, and a sharp increase above. Such high ozone sensitivities are observed for the first time. The observed ozone response is compared with chemistry‐climate simulations from the Hamburg model of the neutral and ionized atmosphere (HAMMONIA) that is forced with an idealized 27‐day solar spectral irradiance time series. Although observational and model results share some common features, substantial discrepancies are found. Namely, the altitude of transition from positive to negative solar ozone correlation signal in the model simulation is found about 10 km below the altitude of the observations and the amplitude of the ozone sensitivity is generally vastly underestimated by the model.
Assessment of the Shielding Effect of the Earth's Magnetic Field on Lunar OH/H2O
Authors: Cho E. , Yi Y. , Yu J. , Hong I. , Choi Y. 
Published: August 2018

AbstractWhen the Moon passes through Earth's magnetosphere, it is believed that the amount of OH/H2O that would typically be created is reduced because the incident solar wind flux on the lunar surface decreases. To confirm this, we analyzed changes in OH/H2O absorption feature in the infrared region with or without the shielding effect of the magnetosphere using Moon Mineralogy Mapper (M3) data in low‐latitude regions. We report that the strength of absorption feature near 3 μm for the region from the equator up to the 10° latitude decreased when the Moon is inside Earth's magnetosphere relative to when it was outside of it. This indicates that the amount of OH/H2O on the shielded surface is less than on the unshielded surface. We confirmed that Earth's magnetosphere affects the OH/H2O distribution at low‐latitude regions, so the OH/H2O on the surface is originated by solar wind implantation. However, this study includes certain level of uncertainties in thermal corrections, and thus, sophisticated additional attempts are needed.
Relationships Among Nutrient and Sediment Fluxes, Hydrological Variability, Fire, and Land Cover in Coastal California Catchments
Authors: Aguilera Rosana , Melack John M. 
Published: August 2018

AbstractCatchments along California's coast, and those with mediterranean climates elsewhere, experience large seasonal and interannual variations in rainfall, and occasional fires; land cover varies from natural vegetation to agricultural and urban development. Multiyear sampling of streams, with intensive collections during rainfall, and continuous measurements of stage, was used to determine the magnitude and variation of concentrations and fluxes of nutrients and suspended sediments during rainfall events and per year from catchments bordering the Santa Barbara Channel. Annual rainfall varied from 18 to 122 cm in water years 2002 through 2015. Hydrological variability, catchment topography, and land cover have strong statistical relationships to nutrient and suspended sediment fluxes. The link between nutrient fluxes and runoff during storms was strongest in sites with greater portions of impervious surfaces. The occurrence of fires followed by above average rainfall resulted in highest ammonium and suspended sediment fluxes. Nitrate fluxes during large storms in undeveloped catchments following wildfire were similar in magnitude to storm fluxes generated in catchments with intensive agriculture. Decreasing storm fluxes were observed with increasing cumulative discharge within a water year, which is consistent with the reduction of flux from each subsequent storm as the rainy season progressed.
Drivers of Dissolved Organic Matter in the Vent and Major Conduits of the World's Largest Freshwater Spring
Authors: Luzius Casey , Guillemette Francois , Podgorski David C. , Kellerman Anne M. , Spencer Robert G. M. 
Published: August 2018

AbstractWakulla Springs is the largest and deepest freshwater spring on Earth and has exhibited increased chromophoric dissolved organic matter (CDOM) inputs (i.e., browning) in recent decades. To examine the drivers of changing dissolved organic matter at the spring vent, we examined dissolved organic carbon concentrations and dissolved organic matter composition via optical parameters (i.e., absorbance and fluorescence) in the major conduits and a connecting spring over the course of 1 year. Sample sites separated clearly based on dissolved organic carbon concentration, CDOM absorbance, and optical parameters indicative of autochthonous (clear groundwater) versus allochthonous (terrestrial) dissolved organic matter. Seasonality was apparent in the allochthonous‐dominated sites with increasing terrestrial contribution particularly with large precipitation events post dry periods. Principle component analysis highlights the ability of optical parameters to show the dominance of sample sites draining from the southwest (i.e., Apalachicola National Forest) as responsible for the CDOM‐rich water at the vent, whereas water draining from the north was comparatively clear. Increasing CDOM‐rich waters at the vent suggests that either input from conduits draining from the southwest has increased, or the relative dilution with clear groundwater has decreased in the conduit system prior to discharge from the vent. Sea level rise impacts in the region have been suggested to result in more blackwaters delivered to the vent, and ongoing extraction of clear groundwater reduces the dilution capacity on CDOM‐rich waters. Thus, anthropogenic impacts in the region need to be addressed if the trend of increased CDOM inputs at Wakulla Springs is to be reversed.
Poynting Flux in the Dayside Polar Cap Boundary Regions From DMSP F15 Satellite Measurements
Authors: Lu Yang , Deng Yue , Sheng Cheng , Kilcommons Liam , Knipp Delores Jane 
Published: August 2018

AbstractPoynting flux, which describes electromagnetic energy flux, is an important energy source for the high‐latitude upper atmosphere. After the launch of Defense Meteorological Satellite Program (DMSP) F15 spacecraft with a boom‐mounted magnetometer on board, there was a new opportunity to calculate Earth‐directed Poynting flux at satellite altitudes (~850 km) in the upper atmosphere. A persistent enhancement of thermospheric density in the dayside polar cap boundary regions has been reported in the CHAMP satellite observations. To understand the significance of different physical mechanisms including Poynting flux and particle precipitation, and the correlation between them, a statistical study of Poytning flux and particle energy flux in the dayside cusp and low‐latitude boundary layer (LLBL) regions has been conducted based on DMSP F15 measurements. DMSP satellite observations showed a dominate downward Poynting flux for most cases in the cusp region. Our analysis of DMSP F15 data for five years (2000–2004) reveals that approximately 53% of 660 cusp crossings at 800–850 km showed strong downward Poynting flux (S > 10 mW/m2), 32% of the crossings had noticeable downward Poynting flux (S > 3 mW/m2), and 7% of the crossings did not show clear Poynting flux (S < 1 mW/m2). Only 13 out of 660 cusp crossings (~2%) showed noticeable upward Poynting flux. In the LLBL region, 35% of 11,641 LLBL crossings showed significant downward Poynting flux, 34% of the crossings had noticeable downward Poynting flux, and only 13% of the crossings did not show clear Poynting flux. On average, Poynting flux in LLBL is smaller than that in the cusp. The results show a slightly negative correlation between Poynting flux and particle precipitation energy flux in the dayside polar cap boundary regions. Statistically, Poynting flux in the cusp is enhanced during interplanetary magnetic field By positive conditions.
Test of Ion Cyclotron Resonance Instability Using Proton Distributions Obtained From Van Allen Probe‐A Observations
Authors: Noh Sung‐Jun , Lee Dae‐Young , Choi Cheong‐Rim , Kim Hyomin , Skoug Ruth 
Published: August 2018

AbstractAnisotropic velocity distributions of protons have long been considered as free energy sources for exciting electromagnetic ion cyclotron (EMIC) waves in the Earth's magnetosphere. Here we rigorously calculated the proton anisotropy parameter using proton data obtained from Van Allen Probe‐A observations. The calculations are performed for times during EMIC wave events (distinguishing the times immediately after and before EMIC wave onsets) and for times exhibiting no EMIC waves. We find that the anisotropy values are often larger immediately after EMIC wave onsets than the times just before EMIC wave onsets and the non‐EMIC wave times. The increase in anisotropy immediately after the EMIC wave onsets is rather small but discernible, such that the average increase is by ~15% relative to the anisotropy values during the non‐EMIC wave times and ~8% compared to those just before the EMIC wave onsets. Based on the calculated anisotropy values, we test the criterion for ion cyclotron instability suggested by Kennel and Petschek (1966, https://doi.org/10.1029/JZ071i001p00001) by applying it to the EMIC wave events. We find that despite the weak increase in anisotropy, the majority of the EMIC wave events satisfy the instability criterion. We suggest that the proton distributions often remain close to the marginal state to ion cyclotron instability, and consequently, the proton anisotropy values should often be observed near threshold values for ion cyclotron instability. Additionally, we demonstrate the usefulness and limitation of the instability criteria expressed in the form of an inverse relation between the anisotropy and plasma beta.
Energetic Particle Showers Over Mars from Comet C/2013 A1 Siding Spring
Authors: Sánchez – Cano Beatriz , Witasse Olivier , Lester Mark , Rahmati Ali , Ambrosi Richard , Lillis Robert , Leblanc François , Blelly Pierre‐Louis , Costa Marc , Cowley Stanley W. H. , Espley Jared R. , Milan Stephen E. , Plaut Jeffrey J. , Lee Christina , Larson Davin 
Published: August 2018

AbstractThis paper is a phenomenological description of multispacecraft observations of energetic particles caused by the close flyby of comet C/2013 A1 Siding Spring with Mars on 19 October 2014. This is the first time that cometary energetic particles have been observed at Mars. The Mars Atmosphere and Volatile EvolutioN (MAVEN)‐solar energetic particle (SEP) and the Mars Odyssey‐High Energy Neutron Detector (HEND) instruments recorded evidence of precipitating particles, which are likely O+ pickup ions, during the ~10 hr that Mars was within the region of the comet's coma. O+ pickup ions were also detected several hours after, although whether their origin is the comet or space weather is not conclusive. We discuss the possible origin of those particles and also the cause of an additional shower of energetic particles that HEND observed between 22 and 35 hr after the comet's closest approach, which may be related to dust impacts from the comet's dust tail. An O+ pickup ion energy flux simulation is performed with representative solar wind and cometary conditions, together with a simulation of their energy deposition profile in the atmosphere of Mars. Results indicate that the O+ pickup ion fluxes observed by SEP were deposited in the ionosphere around 105 to 120 km altitude, and they are compared with precomet flyby estimations of cometary pickup ions. The comet's flyby deposited a significant fluence of energetic particles into Mars' upper atmosphere, at a similar level to a large space weather event.
Effects of St. Patrick's Day Geomagnetic Storm of March 2015 and of June 2015 on Low‐Equatorial D Region Ionosphere
Authors: Maurya Ajeet K. , Venkatesham K. , Kumar Sushil , Singh Rajesh , Tiwari Prabhakar , Singh Abhay K. 
Published: August 2018

AbstractD region effects of the 17–19 March 2015, a St Patrick's Day super geomagnetic storm (Dst = −223 nT), using a navigational transmitter very low frequency (VLF) signal (NWC, 19.8 kHz) recorded at a low‐latitude Indian station, Allahabad (geomag. lat., 16.45°N), have been analyzed and compared with similar strength of the 22–25 June 2015 storm (Dst = −204 nT). During the March storm, NWC signal amplitude decreased on 17 March (main phase of the storm) and recovered on 27 March, which is 1 day after the recovery of the storm, whereas for the June storm, VLF amplitude decreased for 2 days only during its recovery phase. The decrease in the amplitude was pronounced during evening terminator for both the storms. The modeling of VLF signal anomaly on 17 March and on 25 June using Long‐Wave Propagation Capability code shows an increase in the D region reference height (h′) by ~2.6 km and ~2.5 km, for March and June storms, respectively. The D region electron density (Ne) determined using storm time h′ and sharpness factor β shows a decrease in the Ne during the main phase followed by a slow recovery during the recovery phase of the March storm, whereas June 2015 storm showed a decrease in the Ne only on 25 and 26 June. Morlet Wavelet analysis of the amplitude for both the storms shows a presence of strong wave‐like signatures, suggesting propagation of atmospheric gravity waves/traveling ionosphere disturbances to the low latitude D region due to the Joule heating at high latitudes.
Energetic Radiation From Galactic Cosmic Ray Interactions With Saturn's Main Rings
Authors: Cooper John F. , Sturner Steven J. 
Published: August 2018

AbstractSaturn's main rings have an energetic particle and gamma ray photon radiation environment produced by ring interactions of galactic cosmic ray (GCR) protons and heavier ions penetrating the planetary dipolar magnetic field. Accurate models of this radiation environment are important for interpretation of Pioneer 11 and Cassini in situ measurements near the rings and for constraints on radiolytic contributions to neutral gas production and ice chemistry. A GEANT (GEometry ANd Tracking) based simulation is used to model flux spectra of protons, electrons, positrons, charged pions, neutrons, and gamma ray photons emitted from GCR interactions with H2O ice spheres approximating the ring material. Dependent on location in the A to D rings within the planetary magnetic field of Saturn, only GCR protons above respective energies of 20 to 72 GeV can reach the rings without being deflected away by the magnetic field. Calculated differential and integral fluxes from our simulations have good agreement with in situ Pioneer‐11 measurements in selected energy channels. The charged particle and neutral radiation measurements are sensitive, respectively, to the sizes and areal mass densities of ring bodies. Computed gamma ray emission fluxes are 8% of our calculated limit for detection from the Earth by the Fermi Large Area Telescope. Addition of charged particle sensors and neutron‐photon imaging spectrometers to a future Saturn Ring Observer mission would provide valuable information on the ring mass structure. The present paper provides a foundation for modeling of Pioneer 11 and Cassini radiation measurements across the main rings and future measurements of radiation from the rings.