bluuebunny/crossref_metadata_2025_split huggingface dataset:
Propuesta para el análisis de la política fiscal
Authors: Vargas-Hernández José 
Published: August 2015

El trabajo que se presenta, tiene por objetivo analizar la política fiscal en México. Este análisis pretende ser el fundamento teórico-conceptual que como estructura medular sirva de base para la investigación sobre política fiscal en México. Aunque la situación puede parecer muy compleja, la investigación parte del supuesto que la aplicación de la actual políticas fiscal federal tiene implicaciones en el desarrollo económico en general. Se incluye los estudios empíricos sobre el tema a tratar, así como el modelo de política fiscal.
Modeling olivine CPO evolution with complex deformation histories: Implications for the interpretation of seismic anisotropy in the mantle
Authors: Boneh Yuval , Morales Luiz F. G. , Kaminski Edouard , Skemer Philip 
Published: September 2015

AbstractRelating seismic anisotropy to mantle flow requires detailed understanding of the development and evolution of olivine crystallographic preferred orientation (CPO). Recent experimental and field studies have shown that olivine CPO evolution depends strongly on the integrated deformation history, which may lead to differences in how the corresponding seismic anisotropy should be interpreted. In this study, two widely used numerical models for CPO evolution—D‐Rex and VPSC—are evaluated to further examine the effect of deformation history on olivine texture and seismic anisotropy. Building on previous experimental work, models are initiated with several different CPOs to simulate unique deformation histories. Significantly, models initiated with a preexisting CPO evolve differently than the CPOs generated without preexisting texture. Moreover, the CPO in each model evolves differently as a function of strain. Numerical simulations are compared to laboratory experiments by Boneh and Skemer (2014). In general, the D‐Rex and VPSC models are able to reproduce the experimentally observed CPOs, although the models significantly over‐estimate the strength of the CPO and in some instances produce different CPO from what is observed experimentally. Based on comparison with experiments, recommended parameters for D‐Rex are: M* = 10, λ* = 5, and χ = 0.3, and for VPSC: α = 10–100. Numerical modeling confirms that CPO evolution in olivine is highly sensitive to the details of the initial CPO, even at strains greater than 2. These observations imply that there is a long transient interval of CPO realignment which must be considered carefully in the modeling or interpretation of seismic anisotropy in complex tectonic settings.
A new method for calibrating a boron isotope paleo‐pH proxy using massive Porites corals
Authors: Kubota Kaoru , Yokoyama Yusuke , Ishikawa Tsuyoshi , Suzuki Atsushi 
Published: September 2015

AbstractThe boron isotope ratio (δ11B) of marine biogenic carbonates can reconstruct pH and pCO2 of seawater, and potentially CO2 concentration in the atmosphere. To date, δ11B‐pHSW calibration has been proposed via culturing experiments, where calcifying organisms are cultured under artificially acidified seawater. However, in scleractinian corals, reconstructed pH values using culture‐based calibrations do not agree well with actual observations of seawater CO2 chemistry. Thus, another approach is needed to establish a more reliable calibration method. In this study, we established field‐based calibrations for Chichijima and Tahiti, both located in subtropical gyres where surface seawater is close to CO2 equilibrium. We suggest a new approach to calibration of δ11B‐pH in which the long‐term δ11B variation of massive Porites corals is compared with the decreasing pH trend (i.e., ocean acidification) that has occurred since the Industrial Revolution. This calibration will offer a new avenue for studying seawater CO2 chemistry using coral δ11B in diverse settings, such as upwelling regions, coral reefs, and coastal areas.
Vertical kinetic energy and turbulent dissipation in the ocean
Authors: Thurnherr A. M. , Kunze E. , Toole J. M. , St. Laurent L. , Richards K. J. , Ruiz‐Angulo A. 
Published: September 2015

AbstractOceanic internal waves are closely linked to turbulence. Here a relationship between vertical wave number (kz) spectra of fine‐scale vertical kinetic energy (VKE) and turbulent dissipation ε is presented using more than 250 joint profiles from five diverse dynamic regimes, spanning latitudes between the equator and 60°. In the majority of the spectra VKE varies as
. Scaling VKE with
collapses the off‐equatorial spectra to within
but underestimates the equatorial spectrum. The simple empirical relationship between VKE and ε fits the data better than a common shear‐and‐strain fine‐scale parameterization, which significantly underestimates ε in the two data sets that are least consistent with the Garrett‐Munk (GM) model. The new relationship between fine‐scale VKE and dissipation rate can be interpreted as an alternative, single‐parameter scaling for turbulent dissipation in terms of fine‐scale internal wave vertical velocity that requires no reference to the GM model spectrum.
Flow visualization of CO2 in tight shale formations at reservoir conditions
Authors: Fernø M. A. , Hauge L. P. , Uno Rognmo A. , Gauteplass J. , Graue A. 
Published: September 2015

AbstractThe flow of CO2 in porous media is fundamental to many engineering applications and geophysical processes. Yet detailed CO2 flow visualization remains challenging. We address this problem via positron emission tomography using 11C nuclides and apply it to tight formations—a difficult but relevant rock type to investigate. The results represent an important technical advancement for visualization and quantification of flow properties in ultratight rocks and allowed us to observe that local rock structure in a layered, reservoir shale (K = 0.74 µdarcy) sample dictated the CO2 flow path by the presence of high‐density layers. Diffusive transport of CO2 in a fractured sample (high‐permeable sandstone) was also visualized, and an effective diffusion coefficient (Di = 2.2 · 10−8 m2/s) was derived directly from the dynamic distribution of CO2. During CO2 injection tests for oil recovery from a reservoir shale sample we observed a recovery factor of RF = 55% of oil in place without fracturing the sample.
Bimodal distribution of free tropospheric ozone over the tropical western Pacific revealed by airborne observations
Authors: Pan L. L. , Honomichl S. B. , Randel W. J. , Apel E. C. , Atlas E. L. , Beaton S. P. , Bresch J. F. , Hornbrook R. , Kinnison D. E. , Lamarque J.‐F. , Saiz‐Lopez A. , Salawitch R. J. , Weinheimer A. J. 
Published: September 2015

AbstractA recent airborne field campaign over the remote western Pacific obtained the first intensive in situ ozone sampling over the warm pool region from oceanic surface to 15 km altitude (near 360 K potential temperature level). The new data set quantifies ozone in the tropical tropopause layer under significant influence of convective outflow. The analysis further reveals a bimodal distribution of free tropospheric ozone mixing ratio. A primary mode, narrowly distributed around 20 ppbv, dominates the troposphere from the surface to 15 km. A secondary mode, broadly distributed with a 60 ppbv modal value, is prominent between 3 and 8 km (320 K to 340 K potential temperature levels). The latter mode occurs as persistent layers of ozone‐rich drier air and is characterized by relative humidity under 45%. Possible controlling mechanisms are discussed. These findings provide new insight into the physical interpretation of the “S”‐shaped mean ozone profiles in the tropics.
Temporal variability of the South Atlantic Meridional Overturning Circulation between 20°S and 35°S
Authors: Dong Shenfu , Goni Gustavo , Bringas Francis 
Published: September 2015

AbstractAltimetry‐derived synthetic temperature and salinity profiles between 20°S and 34.5°S are used to estimate the Meridional Overturning Circulation (MOC) and meridional heat transport (MHT), which are assessed against estimates obtained from expendable bathythermograph (XBT) measurements. Consistent with studies from XBTs and Argo data, both the geostrophic and Ekman contributions to the MOC exhibit annual cycles and play an equal role in the MOC seasonal variations. The strongest variations on seasonal and interannual time scales in our study region are found at 34.5°S. The dominance of the geostrophic and Ekman components on the interannual variations in the MOC and MHT varies with time and latitude, with the geostrophic component being dominant during 1993–2006 and the Ekman component dominant between 2006 and 2011 at 34.5°S.
Groundwater recharge and age‐depth profiles of intensively exploited groundwater resources in northwest India
Authors: Lapworth D. J. , MacDonald A. M. , Krishan G. , Rao M. S. , Gooddy D. C. , Darling W. G. 
Published: September 2015

AbstractIntensive irrigation in northwest India has led to growing concerns over the sustainability of current and future groundwater abstraction. Environmental tracers and measurements of groundwater residence times can help quantify the renewal processes. Results from 16 paired locations show the interquartile ranges for residence times in shallow alluvial groundwater (8–50 m deep) to be 1–50 years and significantly less than those from deeper groundwater (76–160 m deep) at 40–170 years. The widespread occurrence of modern tracers in deep groundwater (>60% of sites had >10% modern recharge) suggests that there is low regional aquifer anisotropy and that deep aquifers are recharged by a significant component of recent recharge via vertical leakage. Stable isotope and noble gas results at all depths conform to modern meteoric sources and annual average temperatures, with no evidence of significant regional recharge from canal leakage in this study area close to the Himalayas.
Production of nongyrotropic and gyrotropic backstreaming ion distributions in the quasi‐perpendicular ion foreshock region
Authors: Savoini Philippe , Lembège Bertrand 
Published: September 2015

AbstractA curved shock is analyzed in the whole quasi‐perpendicular propagation region (90° ≥ θBn≥45°) in a supercritical regime with the help of a 2‐D particle‐in‐cell code including self‐consistent effects such as the shock front curvature and the time‐of‐flight effects. Two distinct ion populations are observed within the foreshock: a (gyrotropic) field‐aligned beam population, hereafter named “FAB,” and a (nongyrotropic) gyrophase bunched population, hereafter named “GPB.” The origin of these high‐energy particles and their corresponding acceleration mechanisms are analyzed in details in the present paper. Both FAB and GPB populations are shown to be produced by the shock front itself and more important, do have exactly the same origin. At the shock front, the two populations gain a nongyrotropic distribution, but FAB population loses its initial phase coherency after suffering several bounces along the curved front. This result has one main consequence: the time evolution of the two populations does not involve some distinct reflection processes as often claimed in the literature, but results only from the particle time history at the shock front. This important result was not expected and greatly simplifies the question of their origin. More precisely, a new parameter, the injection angle θinj has been defined between the shock normal direction and the ion gyrating velocity vector. We found that the FAB population is formed by ions injected almost along the shock front, while GPB population is formed by ions injected almost along the shock normal.
Frictional characteristics of single and polycrystalline muscovite and influence of fluid chemistry
Authors: Kawai Kenji , Sakuma Hiroshi , Katayama Ikuo , Tamura Kenji 
Published: September 2015

AbstractFrictional experiments were carried out on powder and single crystal specimens of muscovite. Friction coefficients for powder samples were found to be about twice as large as those for single crystals. We found that whereas in single crystal samples sliding occurs along the (001) plane, the situation is more complicated in powder samples. Experiments under wet conditions showed an ~30% reduction in friction coefficient for both powder and single crystal samples compared with dry conditions. The degree of the reduction depended on the fluid chemistry of NaCl or CsCl solutions, indicating that the presence of adsorbed water reduced the friction coefficients. Surface flatness of gauge particles and high affinity of the surface to water were crucial for realizing the effective lubrication due to adsorbed water.
Dynamic Ridges and Valleys in a Strike‐Slip Environment
Authors: Duvall Alison R. , Tucker Gregory E. 
Published: September 2015

AbstractStrike‐slip faults have long been known for characteristic near‐fault landforms such as offset rivers and strike‐parallel valleys. In this study, we use a landscape evolution model to investigate the longer‐term, catchment‐wide landscape response to horizontal fault motion. Our results show that strike‐slip faulting induces a persistent state of disequilibrium in the modeled landscapes brought about by river lengthening along the fault alternating with abrupt shortening due to stream capture. The models also predict that, in some cases, ridges oriented perpendicular to the fault migrate laterally in conjunction with fault motion. We find that ridge migration happens when slip rate is slow enough and/or soil creep and river incision are efficient enough that the landscape can respond to the disequilibrium brought about by strike‐slip motion. Regional rock uplift relative to baselevel also plays a role, as topographic relief is required for ridge migration. In models with faster horizontal slip rates, stronger rocks, or less efficient hillslope transport, ridge mobility is limited or arrested despite the continuance of river lengthening and capture. In these cases, prominent steep, fault‐facing facets form along well‐developed fault valleys. Comparison of landscapes adjacent to fast‐slipping (>30 mm/yr) and slower‐slipping (≤1 mm/yr or less) strike‐slip faults in California, USA, reveals features that are consistent with model predictions. Our results highlight a potential suite of geomorphic signatures that can be used as indicators of horizontal crustal motion and geomorphic processes in strike‐slip settings even after river capture has diminished or erased apparent offset along the fault.
The role of SANSA's geomagnetic observation network in space weather monitoring: A review
Authors: Kotzé P. B. , Cilliers P. J. , Sutcliffe P. R. 
Published: September 2015

AbstractGeomagnetic observations play a crucial role in the monitoring of space weather events. In a modern society relying on the efficient functioning of its technology network such observations are important in order to determine the potential hazard for activities and infrastructure. Until recently, it was the perception that geomagnetic storms had no or very little adverse effect on radio communication and electric power infrastructure at middle‐ and low‐latitude regions like southern Africa. The 2003 Halloween storm changed this perception. In this paper we discuss the role of the geomagnetic observation network operated by the South African National Space Agency (SANSA) in space weather monitoring. The primary objective is to describe the geomagnetic data sets available to characterize and monitor the various types of solar‐driven disturbances, with the aim to better understand the physics of these processes in the near‐Earth space environment and to provide relevant space weather monitoring and prediction.
Resolving two‐dimensional flow structure in rivers using large‐scale particle image velocimetry: An example from a stream confluence
Authors: Lewis Quinn W. , Rhoads Bruce L. 
Published: September 2015

AbstractLarge‐scale particle image velocimetry (LSPIV) has emerged as a valuable tool for measuring surface velocity in a variety of fluvial systems. LSPIV has typically been used in the field to obtain velocity or discharge measurements in relatively simple one‐dimensional flow. Detailed two‐dimensional or three‐dimensional characterization of flow structure has been relegated to laboratory settings because of the difficulty in controlling PIV limiting factors such as poor particle seeding, the need for camera rectification, and challenging field conditions. In this study we implement a low‐cost LSPIV setup using a high‐resolution action camera mounted above a stream confluence and water seeded with recycled landscape mulch. Time‐averaged 2‐D velocities derived from LSPIV are compared with those measured with an acoustic Doppler velocimeter (ADV) in the camera's field of view. We also assess the capabilities of this setup to resolve turbulent and time‐averaged flow structures at a stream confluence. Our results reveal that even in challenging field conditions a basic LSPIV setup can yield accurate data on velocity and resolve in detail the temporal evolution of flow structures on the surface of rivers. The resulting dataset contains velocity information at high spatial and temporal resolution, a significant advance in understanding flow processes at stream confluences. Our LSPIV analysis provides support for previous numerical modeling studies that have distinguished between Kelvin‐Helmholtz and wake modes of turbulent behavior within the mixing interface at confluences. This study shows that LSPIV can provide unprecedented levels of resolution of surface velocity patterns on rivers. Detailed velocity data derived from LSPIV can be used to evaluate numerical predictions of flow structure in complex fluvial environments.
National machine guarding program: Part 1. Machine safeguarding practices in small metal fabrication businesses
Authors: Parker David L. , Yamin Samuel C. , Brosseau Lisa M. , Xi Min , Gordon Robert , Most Ivan G. , Stanley Rodney 
Published: September 2015

BackgroundMetal fabrication workers experience high rates of traumatic occupational injuries. Machine operators in particular face high risks, often stemming from the absence or improper use of machine safeguarding or the failure to implement lockout procedures.MethodsThe National Machine Guarding Program (NMGP) was a translational research initiative implemented in conjunction with two workers' compensation insures. Insurance safety consultants trained in machine guarding used standardized checklists to conduct a baseline inspection of machine‐related hazards in 221 business.ResultsSafeguards at the point of operation were missing or inadequate on 33% of machines. Safeguards for other mechanical hazards were missing on 28% of machines. Older machines were both widely used and less likely than newer machines to be properly guarded. Lockout/tagout procedures were posted at only 9% of machine workstations.ConclusionsThe NMGP demonstrates a need for improvement in many aspects of machine safety and lockout in small metal fabrication businesses. Am. J. Ind. Med. 58:1174–1183, 2015. © 2015 The Authors. American Journal of Industrial Medicine published by Wiley Periodicals, Inc.
Design, Synthesis, and Applications of Highly Phosphorescent Cyclometalated Platinum Complexes
Authors: Huo Shouquan , Carroll Jeffrey , Vezzu Dileep A. K. 
Published: September 2015

AbstractPhosphorescent cyclometalated platinum complexes are highly attractive compounds for a variety of applications, including organic‐light emitting diodes (OLEDs), chemical and biological sensing and imaging, and photocatalysis. This review deals with the progress made in the last five years in the development of highly luminescent platinum complexes based on bidentate, tridentate, and tetradentate cyclometalating ligands. The ligand design and synthesis, general methods for the formation of cycloplatinated complexes, and their photophysical properties, in particular, the emission energy and photoluminescent quantum efficiency of the complexes, are discussed. The applications of the complexes in OLEDs, chemical sensing, biological imaging, and other fields are briefly covered.
Monks on the move: Evaluating pilgrimage to byzantine St. Stephen's monastery using strontium isotopes
Authors: Sheridan Susan Guise , Gregoricka Lesley A. 
Published: September 2015

ABSTRACTObjectivesWritten and archaeological evidence indicates that migration, in the form of pilgrimage to Byzantine Palestine, was a major social phenomenon between the 5th and 7th centuries CE. Monasteries saw record growth at this time as pilgrims chose to stay in the region and take up religious life. A major influx of people to the region, with a corresponding growth in monastic vocations that led travelers to stay in the area, is not in question; however, the distant origins of pilgrims reflected in surviving texts may be an artifact of preservation, biased towards an elite minority. The Byzantine monastery of St. Stephen's provides an opportunity to study this question from a bioarchaeological perspective, given the excellent preservation of the human skeletal assemblage, a wealth of written works about the community as well as daily life in Byzantine Palestine, and a rich archaeological record for the site and region. Materials and Methods: An analysis of radiogenic strontium isotope values from the third molars of 22 individuals recovered from the St. Stephen's crypt complex was conducted to test whether those interred at the monastery were of local origin. Results: Of those examined (
= 0.7084 ± 0.0007, 1σ), 8 out of 22 (36%) exhibited 87Sr/86Sr ratios that fell outside of local ranges. Discussion: These results confirmed the sizeable presence of nonlocals at St. Stephen's Monastery. While most of these migrants likely traveled to Jerusalem from different areas of the Levant as pilgrims, others may have hailed from further afield, including Europe. Am J Phys Anthropol, 2015. © 2015 Wiley Periodicals, Inc. Am J Phys Anthropol 158:581–591, 2015. © 2015 Wiley Periodicals, Inc.
Effect of nitrogen dioxide and sulfur dioxide on viability and morphology of oak pollen
Authors: Ouyang Yuhui , Xu Zhaojun , Fan Erzhong , Li Ying , Zhang Luo 
Published: September 2015

BackgroundNitrogen dioxide (NO2) and sulfur dioxide (SO2) generated by excessive coal combustion and motor vehicle emissions are major air pollutants in the large cities of China. The objective of our study was to determine the effects of the exposure of oak pollens (Quercusmongolica) to several concentrations of NO2 or SO2.MethodsPollen grains were exposed to 0.5 ppm to 5.0 ppm NO2 or SO2 for 4 hours and assessed for morphological damage by field emission scanning electron microscopy and for viability using the trypan blue stain. Morphological changes in pollen grains were also examined after contact with acid solutions at pH 4.0 to pH 7.0.ResultsExposure to NO2 or SO2 significantly damaged pollen grains at all concentrations investigated, compared to exposure to air; with exposure to concentrations of 0.5 ppm to 2 ppm resulting in fissures or complete breaks in the exine and a concentration of 5 ppm resulting in complete breakdown and release of pollen cytoplasmic granules. Significantly greater amounts of pollen grain were damaged after exposure to SO2 (15.5–20.4%) than after exposure to NO2 (7.1–14.7%). Similarly, exposure to NO2 or SO2 significantly decreased the viability of pollen grains, compared with exposure to air; with SO2 being slightly more detrimental than NO2. Exposure to acid solutions also induced pollen damage, which appeared to be pH‐dependent (from 24.6% at pH 6.0 to 55.8% at pH 4.0; compared to 3.8% at pH 7.0).ConclusionShort‐term exposure of oak pollen to high concentrations of SO2 or NO2 significantly increases their fragility and disruption, leading to subsequent release of pollen cytoplasmic granules into the atmosphere. These results suggest that heightened air pollution during the oak pollen season may possibly increase the incidence of allergic airway disease in sensitized individuals by facilitating the bioavailability of airborne pollen allergens.