bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wavelet‐based analogous phase scintillation index for high latitudes
Authors: Ahmed A. , Tiwari R. , Strangeways H. J. , Dlay S. , Johnsen M. G. 
Published: July 2015

AbstractThe Global Positioning System (GPS) performance at high latitudes can be severely affected by the ionospheric scintillation due to the presence of small‐scale time‐varying electron density irregularities. In this paper, an improved analogous phase scintillation index derived using the wavelet‐transform‐based filtering technique is presented to represent the effects of scintillation regionally at European high latitudes. The improved analogous phase index is then compared with the original analogous phase index and the phase scintillation index for performance comparison using 1 year of data from Trondheim, Norway (63.41°N, 10.4°E). This index provides samples at a 1 min rate using raw total electron content (TEC) data at 1 Hz for the prediction of phase scintillation compared to the scintillation monitoring receivers (such as NovAtel Global Navigation Satellite Systems Ionospheric Scintillation and TEC Monitor receivers) which operate at 50 Hz rate and are thus rather computationally intensive. The estimation of phase scintillation effects using high sample rate data makes the improved analogous phase index a suitable candidate which can be used in regional geodetic dual‐frequency‐based GPS receivers to efficiently update the tracking loop parameters based on tracking jitter variance.
Space Weather Concerns for All‐Electric Propulsion Satellites
Authors: Horne Richard B. , Pitchford David 
Published: July 2015

AbstractThe introduction of all‐electric propulsion satellites is a game changer in the quest for low‐cost access to space. It also raises new questions for satellite manufacturers, operators, and the insurance industry regarding the general risks and specifically the threat of adverse space weather. The issues surrounding this new concept were discussed by research scientists and up to 30 representatives from the space industry at a special meeting at the European Space Weather Week held in November 2014. Here we report on the discussions at that meeting. We show that for a satellite undergoing electric orbit raising for 200 days the radiation dose due to electrons is equivalent to approximately 6.7 year operation at geostationary orbit or approximately half the typical design life. We also show that electrons can be injected into the slot region (8000 km) where they pose a risk of satellite internal charging. The results highlight the importance of additional radiation protection. We also discuss the benefits, the operational considerations, the other risks from the Van Allen radiation belts, the new business opportunities for space insurance, and the need for space situation awareness in medium Earth orbit where electric orbit raising takes place.
The relative stability of salmon redds and unspawned streambeds
Authors: Buxton Todd H. , Buffington John M. , Yager Elowyn M. , Hassan Marwan A. , Fremier Alexander K. 
Published: July 2015

AbstractWhere female salmon build nests (“redds”), streambed material is mixed, fine sediment is winnowed, and bed material is moved into a tailspill mound resembling the shape of a dune. Completed redd surfaces are coarser and better sorted than unspawned beds, which is thought to increase redd stability because larger grains are heavier and harder to move, and sorting increases friction angles for mobility. However, spawning also loosens sediment and creates topography that accelerates flow, which can increase particle mobility. We address these factors controlling the relative stability of redds and unspawned beds in flume experiments where redds were constructed with a dynamic technique that mimics the nesting behavior of female salmon. Although redds exhibited relatively coarse surfaces, measured entrainment forces indicate particle loosening by spawning lowered grain resistance to motion by 12–37% on average compared to unspawned beds. In addition, for the same discharges, boundary shear stress was 13–41% higher on a redd due to flow convergence on the tailspill. Visual measurements of particle entrainment further indicated redd instability, as bed‐average shear stress was 22% lower at incipient motion and 29% lower at the discharge that mobilized all grain sizes on a redd. Overall, results demonstrate that redds are unstable compared to unspawned beds, which increases the risk of scour for buried eggs but may facilitate fine sediment flushing and improve the quality of spawning gravels for future generations of spawners. Therefore, managing salmon returns to increase streambed disturbance may be an effective tool for reducing sedimentation impacts on salmon reproduction.
On the use of rhodamine WT for the characterization of stream hydrodynamics and transient storage
Authors: Runkel Robert L. 
Published: July 2015

AbstractRecent advances in fluorometry have led to increased use of rhodamine WT as a tracer in streams and rivers. In light of this increased use, a review of the dye's behavior in freshwater systems is presented. Studies in the groundwater literature indicate that rhodamine WT is transported nonconservatively, with sorption removing substantial amounts of tracer mass. Column studies document a two‐step breakthrough curve in which two structural isomers are chromatographically separated. Although the potential for nonconservative transport is acknowledged in the surface water literature, many studies assume that sorptive losses will not affect the characterization of physical transport processes. A literature review and modeling analysis indicates that this assumption is valid for quantification of physical properties that are based on the bulk of the tracer mass (traveltime), and invalid for the characterization of processes represented by the tracer tail (transient storage attributable to hyporheic exchange). Rhodamine WT should be considered nonconservative in the hyporheic zone due to nonconservative behavior demonstrated for similar conditions in groundwater. As such, rhodamine WT should not be used as a quantitative tracer in hyporheic zone investigations, including the study of long flow paths and the development of models describing hyporheic zone processes. Rhodamine WT may be used to qualitatively characterize storage in large systems, where there are few practical alternatives. Qualitative investigations should rely on early portions of the tracer profile, making use of the temporal resolution afforded by in situ fluorometry, while discarding later parts of the tracer profile that are adversely affected by sorption.
Interdependence of chronic hydraulic dysfunction and canopy processes can improve integrated models of tree response to drought
Authors: Mackay D. Scott , Roberts David E. , Ewers Brent E. , Sperry John S. , McDowell Nathan G. , Pockman William T. 
Published: July 2015

AbstractHydraulic systems of plants have evolved in the context of carbon allocation and fitness trade‐offs of maximizing carbon gain and water transport in the face of short and long‐term fluctuations in environmental conditions. The resulting diversity of traits include a continuum of isohydry‐anisohydry or high to low relative stomatal closure during drought, shedding of canopy foliage or disconnecting roots from soil to survive drought, and adjusting root areas to efficiently manage canopy water costs associated with photosynthesis. These traits are examined within TREES, an integrated model that explicitly couples photosynthesis and carbon allocation to soil‐plant hydraulics and canopy processes. Key advances of the model are its ability to account for differences in soil and xylem cavitation, transience of hydraulic impairment associated with delayed or no refilling of xylem, and carbon allocation to plant structures based on photosynthetic uptake of carbon and hydraulic limitations to water transport. The model was used to examine hydraulic traits of cooccurring isohydric (piñon pine) and anisohydric (one‐seed juniper) trees from a field‐based experimental drought. Model predictions of both transpiration and leaf water potential were improved when there was no refilling of xylem over simulations where xylem was able refill in response to soil water recharge. Model experiments with alternative root‐to‐leaf area ratios (RR/L) showed the RR/L that supports maximum cumulative water use is not beneficial for supporting maximum carbon gain during extended drought, illustrating how a process model reveals trade‐offs in plant traits.
Persistent questions of heterogeneity, uncertainty, and scale in subsurface flow and transport
Authors: Kitanidis Peter K. 
Published: July 2015

AbstractWhen Water Resources Research was launched in 1965, heterogeneity, uncertainty, and scale issues in subsurface hydrology were in the backburner. Only about 10 years later, under the stimulus of dealing with solute transport problems, these problems received attention. The stochastic approach brought tools to deal both with problems of upscaling, also known as homogenization and coarse‐graining, and uncertainty quantification. Effective conductivity and effective dispersion, also known as macrodispersion, coefficients in statistically homogeneous formations were extensively studied. Mixing, in its role of affecting reaction rates, started receiving attention. While in the dispersion problem emphasis was on Fickian representations, more sophisticated models have also been studied. Uncertainty quantification in the inverse problem has also made progress and geostatistical ideas, as well as ideas originating in signal processing, influenced how we approach problems of inference like interpolation and inverse modeling. My view is that we should emphasize information aspects, i.e., the collection of more and better data, their correct assimilation, the quantification of uncertainty associated with predictions, and the selection of designs or policies that accurately reflect what we actually know and thus manage risk. Progress in this department has been hampered by ingrained ideas, inadequate training, and inadequate resources. Research in problems of upscaling will continue to shed new light and provide better tools to deal with onerous problems. At the same time, no cure is more universally potent than using a more refined grid. Finally, although research is active, the diffusion of research results to education and practice has been slow.
Does the Narrative Style of Video Evidence Influence Judgements About Rape Complainant Testimony?
Authors: Westera Nina J. , McKimmie Blake M. , Kebbell Mark R. , Milne Rebecca , Masser Barbara 
Published: July 2015

SummaryFour studies investigated lawyers' concerns that the narrative style of police interviews with adult rape complainants reduces the impact of this interview as video evidence. Study 1 (N = 96) compared mock juror perceptions of simulated evidence‐in‐chief either in traditional short‐answer or narrative style and found testimony style was not a predictor of complainant credibility. Studies 2 (N = 104), 3 (N = 102) and 4 (N = 102) examined different variables that change with testimony style—the number of questions asked, overall testimony length and response length. The number of questions asked was the only predictor of complainant credibility; more questions resulted in higher credibility ratings. These findings suggest that lawyers' concerns about narrative style interviewing are unwarranted. Copyright © 2015 John Wiley & Sons, Ltd.
Jaw‐muscle force and excursion scale with negative allometry in platyrrhine primates
Authors: Taylor Andrea B. , Yuan Tian , Ross Callum F. , Vinyard Christopher J. 
Published: July 2015

ABSTRACTObjectivesPlatyrrhines span two orders of magnitude in body size and are characterized by diverse feeding behaviors and diets. While size plays an important role in primate feeding behavior and masticatory apparatus morphology, we know little about size‐correlated changes in the force‐generating (physiologic cross‐sectional area; PCSA) and excursion/stretch (fiber length; Lf) capabilities of the jaw‐closing muscles in platyrrhines.MethodsWe examined scaling relationships of the superficial masseter and temporalis muscles in 21 platyrrhine species. Previous work suggests that larger platyrrhines are at a mechanical disadvantage for generating bite forces compared with smaller platyrrhines. We hypothesize that scaling of jaw‐muscle fiber architecture counters this size‐correlated decrease in mechanical advantage. Thus, we predicted that jaw‐muscle PCSAs and muscle weights scale with positive allometry while Lfs scale with negative allometry, relative to load‐arm estimates for incisor/molar biting and chewing.ResultsJaw‐muscle PCSAs and Lfs appear to scale with negative allometry relative to load‐arm estimates and body size. Negative allometry of jaw‐muscle weights partially accounts for the size‐correlated decreases in PCSA and Lf. Estimates of bite force also scale with negative allometry.ConclusionLarge‐bodied platyrrhines (e.g., Alouatta) are at a relative disadvantage for generating jaw‐muscle and bite force as well as jaw‐muscle stretch, compared with smaller species (e.g., Callithrix). The net effect is that larger platyrrhines likely produce relatively smaller maximal bite forces compared with smaller taxa. Relative to small‐ and intermediate‐sized platyrrhines, large‐bodied platyrrhines feed on some of the least mechanically challenging foods, consistent with the size‐correlated decrease in relative muscle and bite forces across the clade. Am J Phys Anthropol, 2015. © 2015 Wiley Periodicals, Inc. Am J Phys Anthropol 158:242–256, 2015. © 2015 Wiley Periodicals, Inc.
New dental and isotope evidence of biological distance and place of origin for mass burial groups atCahokia's mound 72
Authors: Thompson Andrew R. , Hedman Kristin M. , Slater Philip A. 
Published: July 2015

ABSTRACTObjectives:Mound 72 at Cahokia figures prominently into interpretations of early Mississippian sociopolitical development. A previous study utilizing dental morphology concluded that the groups of mostly young adult females interred in four mass graves in Mound 72 were likely not from Cahokia and possibly reflect sacrificial offerings from outside communities. The purpose of this study is to reevaluate these findings using multiple indicators of biological relatedness and place of origin/migration.Materials and Methods:Biological relatedness in Mound 72 was examined using dental metrics and morphology. Four additional archaeological samples from nearby sites were included to better assess biological variation within Mound 72. Strontium isotope analysis (87Sr/86Sr) was also conducted on individuals from several burial features in Mound 72 to determine heterogeneity in place of origin.Results:Biodistance studies indicate that individuals in the four mass graves are phenotypically similar to other groups in the region, whereas F229‐lower, a burial group with an aberrant mortuary context, is phenotypically distinct. Strontium isotope analyses show that mean Sr signatures for each feature investigated fall within the established local range for Cahokia. However, the range of Sr ratios for individuals in F229‐lower is very narrow, suggesting they reflect a single population from a limited geologic region.Discussion:Collectively, these results question the long‐standing idea that individuals in the four mass graves were non‐local to Cahokia and suggest that F229‐lower contained a biologically dissimilar group that either came from an outside region with a similar Sr signature to Cahokia, or represent a distinct and restricted group from the region. Am J Phys Anthropol 158:341–357, 2015. © 2015 Wiley Periodicals, Inc.
An enhanced computational method for age‐at‐death estimation based on the pubic symphysis using 3D laser scans and thin plate splines
Authors: Stoyanova Detelina , Algee‐Hewitt Bridget F.B. , Slice Dennis E. 
Published: July 2015

ABSTRACTObjectives:The pubic symphysis is frequently used to estimate age‐at‐death from the adult skeleton. Assessment methods require the visual comparison of the bone morphology against age‐informative characteristics that represent a series of phases. Age‐at‐death is then estimated from the age‐range previously associated with the chosen phase. While easily executed, the "morphoscopic" process of feature‐scoring and bone‐to‐phase‐matching is known to be subjective. Studies of method and practitioner error demonstrate a need for alternative tools to quantify age‐progressive change in the pubic symphysis. This article proposes a more objective, quantitative method that analyzes three‐dimensional (3D) surface scans of the pubic symphysis using a thin plate spline algorithm (TPS).Materials and Methods:This algorithm models the bending of a flat plane to approximately match the surface of the bone and minimizes the bending energy required for this transformation. Known age‐at‐death and bending energy were used to construct a linear model to predict age from observed bending energy. This approach is tested with scans from 44 documented white male skeletons and 12 casts.Results:The results of the surface analysis show a significant association (regression p‐value = 0.0002 and coefficient of determination = 0.2270) between the minimum bending energy and age‐at‐death, with a root mean square error of ≈19 years.Discussion:This TPS method yields estimates comparable to established methods but offers a fully integrated, objective and quantitative framework of analysis and has potential for use in archaeological and forensic casework. Am J Phys Anthropol 158:431–440, 2015. © 2015 Wiley Periodicals, Inc.
Association of protein intakes and variation of diet‐scalp hair nitrogen isotopic discrimination factor in Papua New Guinea highlanders
Authors: Naito Yuichi I. , Morita Ayako , Natsuhara Kazumi , Tadokoro Kiyoshi , Baba Jun , Odani Shingo , Tomitsuka Eriko , Igai Katsura , Tsutaya Takumi , Yoneda Minoru , Greenhill Andrew R. , Horwood Paul F. , Soli Kevin W. , Phuanukoonnon Suparat , Siba Peter M. , Umezaki Masahiro 
Published: July 2015

ABSTRACTObjectives:We present new nitrogen isotopic discrimination factor between diets and scalp hairs (Δ15NHair‐Diet: δ15NHair – δ15NDiet) for indigenous residents in three communities in the Papua New Guinea Highlands who consumed various amounts and qualities of protein. The Δ15N is important for precise evaluation of the dietary habits of human populations; in both contemporary and traditional lifestyles. Several hypotheses have been proposed regarding factors that affect Δ15N values, based largely on observations from animal feeding experiments. However, variations and factors controlling Δ15N in humans are not well understood, mainly due to the difficulty of controlling the diets of participants.Materials and Methods:These residents were studied because they have maintained relatively traditional dietary habits, which allow quantitative recording of diets. Δ15N was estimated by comparing hair δ15N values to mean dietary δ15N values calculated from the recorded intake of each food item and their δ15N values.Results:The results showed that: i) there was a significant difference in Δ15N among study locations (3.9 ± 0.9‰ for most urbanized, 5.2 ± 1.0‰ for medium and 5.0 ± 0.9‰ for least urbanized communities; range = 1.2–7.3‰ for all participants); and ii) estimated Δ15N values were negatively correlated with several indicators of animal protein intake (% nitrogen in diet: range = 0.9–7.6%).Discussion:We hypothesize that a combination of several factors, which presumably included urea recycling and amino acid and protein recycling and/or de novo synthesis during metabolic processes, altered the Δ15N values of the participants. Am J Phys Anthropol 158:359–370, 2015. © 2015 Wiley Periodicals, Inc.
Ancient remains and the first peopling of the Americas: Reassessing the Hoyo Negro skull
Authors: de Azevedo Soledad , Bortolini Maria C. , Bonatto Sandro L. , Hünemeier Tábita , Santos Fabrício R. , González‐José Rolando 
Published: July 2015

ABSTRACTObjectiveA noticeably well‐preserved ∼12.500 years‐old skeleton from the Hoyo Negro cave, Yucatán, México, was recently reported, along with its archaeological, genetic and skeletal characteristics. Based exclusively on an anatomical description of the skull (HN5/48), Chatters and colleagues stated that this specimen can be assigned to a set of ancient remains that differ from modern Native Americans, the so called “Paleoamericans”. Here, we aim to further explore the morphological affinities of this specimen with a set of comparative cranial samples covering ancient and modern periods from Asia and the Americas.MethodsImages published in the original article were analyzed using geometric morphometrics methods. Shape variables were used to perform Principal Component and Discriminant analysis against the reference samples.ResultsEven thought the Principal Component Analysis suggests that the Hoyo Negro skull falls in a subregion of the morphospace occupied by both “Paleoamericans” and some modern Native Americans, the Discriminant analyses suggest greater affinity with a modern Native American sample.DiscussionThese results reinforce the idea that the original population that first occupied the New World carried high levels of within‐group variation, which we have suggested previously on a synthetic model for the settlement of the Americas. Our results also highlight the importance of developing formal classificatory test before deriving settlement hypothesis purely based on macroscopic descriptions. Am J Phys Anthropol 158:514–521, 2015. © 2015 Wiley Periodicals, Inc.
Single‐limb force data for two lemur species while vertically clinging
Authors: Johnson Laura E. , Hanna Jandy , Schmitt Daniel 
Published: July 2015

ABSTRACTObjectivesVertical clinging and climbing have been integral to hypotheses about primate origins, yet little is known about how an animal with nails instead of claws resists gravity while on large, vertical, and cylindrical substrates. Here we test models of how force is applied to maintain posture, predicting (1) the shear component force (Fs) at the hands will be higher than the feet; (2) the normal component force (Fn) at the feet will be relatively high compared to the hands; (3) the component force resisting gravity (Fg) at the feet will be relatively high compared to the hands; (4) species with a high frequency of vertical clinging postures will have low Fg at the hands due to relatively short forelimbs.Materials and MethodsUsing a novel instrumented support, single‐limb force data were collected during clinging postures for the hands and feet and compared across limbs and species for Propithecus verreauxi (N = 2), a habitual vertical clinger and leaper, and Varecia variegata (N = 3), a habitual above‐branch arboreal quadruped.ResultsFor both species, hand Fs were significantly higher than at the feet and Fn and Fg at the feet were significantly higher than at the hands. Between species, P. verreauxi has relatively low Fg at the hands and Fn at the feet than V. vareigata.DiscussionThese results support previous models and show that hindlimb loading dominance, characteristic of primate locomotion, is found during clinging behaviors and may allow the forelimbs to be used for foraging while clinging. These findings provide insight into selective pressures on force distribution in primates and primate locomotor evolution. Am J Phys Anthropol 158:463–474, 2015. © 2015 Wiley Periodicals, Inc.