bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spectral Induced Polarization measurements on New Zealand sands ‐ dependence on fluid conductivity
Authors: Joseph Sheen , Ingham Malcolm , Gouws Gideon 
Published: January 2015

ABSTRACTSpectral induced polarization (SIP) measurements explore the variation of the complex conductivity of a material with frequency. Much of this variation results from polarization effects associated with the electric double layer on the surfaces of pore spaces. The consequent dependence of the SIP signature on pore structure thus has the potential to provide a link to the hydraulic properties of the material, which have a similar dependence. We report here on the variation of the SIP signature of unconsolidated sands, typical of those found in coastal aquifers in New Zealand, with the conductivity of the pore fluid. The SIP parameters of the measurements are modelled in terms of a Cole‐Cole model and demonstrate the independence of relaxation time on fluid conductivity. The contribution of surface conductivity to the overall conductivity is calculated and the variation of the imaginary part of the surface conductivity with fluid conductivity is tested against two models for the origin of surface conductivity. The measured hydraulic conductivity is also compared with estimates provided by three proposed equations relating hydraulic properties to structural and electric properties.
Deriving shallow‐water sediment properties using post‐stack acoustic impedance inversion
Authors: Vardy Mark E. 
Published: January 2015

ABSTRACTIn contrast to the use of marine seismic reflection techniques for reservoir‐scale applications, where seismic inversion for quantitative sediment analysis is common, shallow‐waterm, very‐high‐resolution seismic reflection data are seldom used for more than qualitative reflection interpretation. Here, a quantitative analysis of very‐high‐resolution marine seismic reflection profiles from a shallow‐water (<50 m water depth) fjord in northern Norway is presented. Acquired using Sparker, Boomer, and Chirp sources, the failure plane of multiple local landslides correlates with a composite reflection that reverses polarity to the south. Using a genetic algorithm, a 1D post‐stack acoustic impedance inversion of all three profiles is performed, calibrating against multi‐sensor core logger (MSCL) data from cores. Using empirical relationships the resulting impedance profiles are related to remote sediment properties, including: P‐wave velocity; density; mean grain size; and porosity. The composite reflector is consistently identified by all three data sources as a finer‐grained (by one ), lower density (c. 0.2 g/cm3 less than background) thin bed, with an anomalous low velocity zone (at least 100 m/s lower than background) associated with the polarity reversal to the south. Such a velocity contrast is consistent with an accumulation of shallow free gas trapped within the finer‐grain, less permeable layer. This study represents the first application of acoustic impedance inversion to very‐high‐resolution seismic reflection data and demonstrates the potential for directly relating seismic reflection data with sediment properties using a variety of commonly used shallow seismic profiling sources.
Seismic monitoring and vibrational characterization of small wind turbines: A case study of the potential effects on the Eskdalemuir International Monitoring System Station in Scotland
Authors: Westwood Rachel F. , Styles Peter , Toon Samuel M. 
Published: January 2015

ABSTRACTThis paper presents a case study of the ground‐borne vibrations generated by small wind turbines. This is of particular importance for assessing the possible impact on the detection capabilities of the International Monitoring System seismic array at Eskdalemuir in Scotland. Measurements were gathered from a selection of small wind turbines (≤50 kW), from three different manufacturers, varying in hub height, power and construction using a range of accelerometers and seismometers fixed to the tower and buried in the adjacent ground at increasing distances. Previous studies have shown that medium and large turbines generate harmonic vibrations. Planning guidelines exist but have inadvertently led to a ban on the deployment of individual small‐turbines within 50 km of the array. This study investigates whether their inclusion in these guidelines is necessary.Vibration levels on the tower are in the region of 10−3 m/sqrt(Hz), are transferred into the ground and decay rapidly away from the turbine (10−5 m/sqrt(Hz) in the ground at 200 m). The spectral content of the vibrations shows variations between the turbines, but each have peaks in the band of interest for Eskdalemuir. Further, sources of the peaks in the spectra are identified as either originating from the blades’ rotation or the resonant modes of the turbines.Analysis of the relationship between wind speed and seismic amplitude on the tower shows an exponential trend, individual to each wind turbine and the frequency band of interest. Similarly, analysis of the seismic amplitude between the tower and foundation shows that this can be described by a power law, but this is individual to each turbine. It is our opinion that there is little requirement to include turbines of 50 kW or less in planning guidelines outside the statutory exclusion zone of 10 km, but each turbine should be considered on an individual basis.
Mapping the spatial variation of soil moisture at the large scale using GPR for pavement applications
Authors: Benedetto Andrea , Tosti Fabio , Ortuani Bianca , Giudici Mauro , Mele Mauro 
Published: January 2015

ABSTRACTThe characterization of shallow soil moisture spatial variability at the large scale is a crucial issue in many research studies and fields of application ranging from agriculture and geology to civil and environmental engineering. In this framework, this work contributes to the research in the area of pavement engineering for preventing damages and planning effective management. High spatial variations of subsurface water content can lead to unexpected damage of the load‐bearing layers; accordingly, both safety and operability of roads become lower, thereby affecting an increase in expected accidents.A pulsed ground‐penetrating radar system with ground‐coupled antennas, i.e., 600‐MHz and 1600‐MHz center frequencies of investigation, was used to collect data in a 16 m × 16 m study site in the Po Valley area in northern Italy. Two ground‐penetrating radar techniques were employed to non‐destructively retrieve the subsurface moisture spatial profile. The first technique is based on the evaluation of the dielectric permittivity from the attenuation of signal amplitudes. Therefore, dielectrics were converted into moisture values using soil‐specific coefficients from Topp’s relationship. Ground‐penetrating‐radar‐derived values of soil moisture were then compared with measurements from eight capacitance probes. The second technique is based on the Rayleigh scattering of the signal from the Fresnel theory, wherein the shifts of the peaks of frequency spectra are assumed comprehensive indicators for characterizing the spatial variability of moisture. Both ground‐penetrating radar methods have shown great promise for mapping the spatial variability of soil moisture at the large scale.
Management of Loose, Frequent Stools and Fecal Incontinence in a Chronic Mesenteric Ischemia Patient with Oral Serum-derived Bovine Immunoglobulin
Authors: Good Larry , Burnett Bruce P. 
Published: January 2015

Aim Chronic diarrhea with fecal incontinence (FI) is a severe, underreported, and intractable problem in many patients for which limited pharmaceutical options exist. Methods A retrospective case history was collected after the administration of a prescription medical food composed of serum-derived bovine immunoglobulin/protein isolate (SBI) at 5 g once daily in a patient with chronic mesenteric ischemia (CMI) for chronic loose, frequent, and urgent stools. The patient was an 84-year-old white male with a 20-year history of progressively worsening chronic diarrhea with six to eight watery stools per day (Bristol Stool Form Scale, Type 7), urgency, nocturnal diarrhea, FI, and postprandial abdominal discomfort before administration of SBI. Results After four weeks of SBI administration, the patient had two to three soft, semi-formed stools (Bristol Stool Form Scale, Types 4 and 5) per day with no nocturnal diarrhea, urgency, or FI, as well as full resolution of abdominal discomfort. In addition, the patient expressed an enhanced quality of life (QoL): able to travel, attend social events, and perform tasks not possible before therapy. Conclusion This case underscores how a safe, nutritional therapy may offer a new modality for physicians to address chronic loose, frequent stools with FI in patients with CMI in this difficult to manage gastrointestinal population.
Cooptation et résistance dans la planification forestière concertée au Québec
Authors: Fortier Jean-François , Wyatt Stephen 
Published: January 2015

Définies comme des processus de concertation où les utilisateurs du territoire sont invités à élaborer une vision commune de la gestion des territoires forestiers, les tables de gestion intégrée des ressources et du territoire (« tables GIRT ») sont apparues au Québec en 2010. Cet article explore la participation des Atikamekw Nehirowisiwok à ces tables, et contrairement à d’autres études qui tendent à interpréter les processus collaboratifs comme un modèle idéal « gagnant-gagnant » ou comme une stratégie de cooptation de la participation autochtone, les auteurs proposent ici d’examiner les processus de concertation comme un lieu où se manifestent à la fois des formes de résistance et de cooptation. De plus, les résultats démontrent que la participation autochtone aux tables GIRT gagne à être comprise en tenant compte des autres processus dans lesquels les Premières Nations sont également engagées.
Les symptômes de la faillite : le cas de la Belgique
Authors: Brédart Xavier 
Published: January 2015

À l’instar de nombreux autres pays, la Belgique a fait face à un nombre croissant de faillites d’entreprises depuis la crise des « subprimes ». Ce nombre a, en effet, augmenté d’un peu plus de 43 % entre 2007 et 2012. Sur base d’un échantillon d’entreprises belges couvrant une période allant de 2002 à 2010, cet article a pour but de développer trois modèles économétriques de prévision construits à partir de six ratios financiers, respectivement à un, trois et cinq ans avant la faillite. Outre l’apport académique à la recherche relative à la prévision des faillites en Belgique, les résultats de cette étude empirique peuvent être utiles au sein du monde professionnel, notamment pour les institutions financières intéressées par le risque de faillite de leurs partenaires.
Can human populations be stabilized?
Authors: Warren Stephen G. 
Published: January 2015

AbstractHistorical examples of demographic change, in China, Italy, Nigeria, Utah, Easter Island, and elsewhere, together with simple mathematics and biological principles, show that stabilizing world population before it is limited by food supply will be more difficult than is generally appreciated. United Nations population projections are wrong because they assume, in spite of the absence of necessary feedbacks, that all nations will converge rapidly to replacement‐level fertility and thereafter remain at that level. Education of women and provision of contraceptives have caused dramatic reductions in fertility, but many groups, including some that are well‐educated, maintain high fertility. Small groups with persistent high fertility can grow to supplant low‐fertility groups, resulting in continued growth of the total population. The global average fertility rate could rise even if each country's fertility rate is falling. In some low‐fertility European countries where deaths exceed births, the population continues to grow because of immigration. Producing more than two offspring is normal for all animal species with stable populations because their populations are limited by resources or predation rather than birth control. It may therefore be appropriate to view the growth of human population as the result not of excess fertility but rather of excess food.
Earthquake hypocenters and focal mechanisms in central Oklahoma reveal a complex system of reactivated subsurface strike‐slip faulting
Authors: McNamara D. E. , Benz H. M. , Herrmann R. B. , Bergman E. A. , Earle P. , Holland A. , Baldwin R. , Gassner A. 
Published: January 2015

AbstractThe sharp increase in seismicity over a broad region of central Oklahoma has raised concern regarding the source of the activity and its potential hazard to local communities and energy industry infrastructure. Since early 2010, numerous organizations have deployed temporary portable seismic stations in central Oklahoma in order to record the evolving seismicity. In this study, we apply a multiple‐event relocation method to produce a catalog of 3639 central Oklahoma earthquakes from late 2009 through 2014. Regional moment tensor (RMT) source parameters were determined for 195 of the largest and best recorded earthquakes. Combining RMT results with relocated seismicity enabled us to determine the length, depth, and style of faulting occurring on reactivated subsurface fault systems. Results show that the majority of earthquakes occur on near‐vertical, optimally oriented (NE‐SW and NW‐SE), strike‐slip faults in the shallow crystalline basement. These are necessary first‐order observations required to assess the potential hazards of individual faults in Oklahoma.
Monsoon oscillations regulate fertility of the Red Sea
Authors: Raitsos Dionysios E. , Yi Xing , Platt Trevor , Racault Marie‐Fanny , Brewin Robert J. W. , Pradhan Yaswant , Papadopoulos Vassilis P. , Sathyendranath Shubha , Hoteit Ibrahim 
Published: January 2015

AbstractTropical ocean ecosystems are predicted to become warmer, more saline, and less fertile in a future Earth. The Red Sea, one of the warmest and most saline environments in the world, may afford insights into the function of the tropical ocean ecosystem in a changing planet. We show that the concentration of chlorophyll and the duration of the phytoplankton growing season in the Red Sea are controlled by the strength of the winter Arabian monsoon (through horizontal advection of fertile waters from the Indian Ocean). Furthermore, and contrary to expectation, in the last decade (1998–2010) the winter Red Sea phytoplankton biomass has increased by 75% during prolonged positive phases of the Multivariate El Niño–Southern Oscillation Index. A new mechanism is reported, revealing the synergy of monsoon and climate in regulating Red Sea greenness.
Systematic averaging interval effects on solar wind statistics
Authors: Isaacs J. J. , Tessein J. A. , Matthaeus W. H. 
Published: January 2015

AbstractThe choice of interval of averaging in computing statistics of solar wind fluctuations is known to be a sensitive issue in which the need for adequate sampling statistics must be balanced with the complications of establishing an ensemble, given that the solar wind admits inhomogeneity, structure, and variability at its sources. Here we examine the quantitative dependence of interval of averaging (sample size) on estimates of basic statistics such as means, variances, and anisotropies of the measured interplanetary magnetic field.
Case studies of nonorographic gravity waves over the Southern Ocean emphasize the role of moisture
Authors: Plougonven Riwal , Hertzog Albert , Alexander M. Joan 
Published: January 2015

AbstractTwo case studies of nonorographic gravity waves are carried out for wave events that occurred over the Southern Ocean in November 2005. Mesoscale simulations were carried out with the Weather and Research Forecast model. The simulated waves were compared to observations from superpressure balloons of the Vorcore campaign and from the High Resolution Dynamic Limb Sounder satellite. Satisfactory agreement is found, giving confidence in the estimations of wave parameters and amplitudes. For the amplitudes, both the model and observations provide a lower bound, for different reasons. Waves are found in the lower stratosphere with horizontal wavelengths of the order of 150–200 km in the horizontal, 5–8 km in the vertical, corresponding to intrinsic frequencies between 5 and 10 f, where f is the Coriolis parameter. Although the tropospheric flow is very different between the two cases, there are features which are common and appear significant for the gravity waves: these include intense localized updrafts associated with convection in the troposphere and a displaced polar vortex inducing strong winds in the stratosphere above the frontal region. Relative to theoretical expectations, the simulations emphasize the role of moisture. Intrinsic frequencies are significantly higher than those expected for waves produced by dry spontaneous generation from jets. To quantify the contribution of moisture, dry simulations were carried out, yielding momentum fluxes over oceanic regions that were 2.5 times weaker. Identification of the generation mechanisms in these complex flows calls for further study, and these should include moisture and a realistic stratospheric jet.
Monitoring a convective winter episode of the Iberian Peninsula using a multichannel microwave radiometer
Authors: Gascón E. , Sánchez J. L. , Fernández‐González S. , Hermida L. , López L. , García‐Ortega E. , Merino A. 
Published: January 2015

AbstractOn 4 March 2011, a heavy snowfall episode affected the central Iberian Peninsula. Under the TECOAGUA Project (aimed at the study of winter cloud masses that produce snow in the Guadarrama Mountains near Madrid), measurements using a ground‐based multichannel microwave radiometer (MMWR) with vertical range 10 km recorded this episode of winter convection embedded within stratiform precipitation. In contrast to radiosondes, data retrieval from the MMWR has a clear advantage for identifying hazardous weather phenomena of short duration, such as winter convective episodes. From these continuous measurements, we analyzed the behavior of variables such as temperature, surface pressure, relative humidity, liquid water content, liquid water path, water vapor content, and integrated water vapor throughout the day. The continuous measurements also permitted construction of skew‐T log‐P profiles every 15 min during the convective episode, indicating vertical evolution of an event with an appearance similar to a “zipper” in which temperature and dew point temperature profiles are “closed” from the surface to 400 hPa and “reopen” at the end of the event. Finally, we selected six indices of stability most suitable for the study of winter convection, namely, the Showalter index, low‐topped convection index, most unstable lifted index, most unstable convective available potential energy (MUCAPE), convective inhibition, and MUCAPE level of free convection. Each of these indices has been evaluated for their capacity to warn of meteorological conditions leading to a convective heavy snowfall event.
The evolution of deep‐ocean flow speeds and δ13C under large changes in the Atlantic overturning circulation: Toward a more direct model‐data comparison
Authors: Bakker Pepijn , Govin Aline , Thornalley David J. R. , Roche Didier M. , Renssen Hans 
Published: January 2015

AbstractTo investigate the dynamics of the Atlantic meridional overturning circulation (AMOC) on timescales longer than the observational records, model‐data comparisons of past AMOC variability are imperative. However, this remains challenging because of dissimilarities between different proxy‐based AMOC tracers and the difficulty of comparing these to model output. We present an iLOVECLIM simulation with tuned AMOC evolution and focus on AMOC tracers that are directly comparable to reconstructions: flow speeds and δ13C. We deduce their driving factors and show that they yield different but complementary information about AMOC changes. Simulated flow speed changes are only linked to AMOC changes in regions bathed by North Atlantic Deep Water; however, in those regions they do provide details on vertical migration and thickness changes of the water masses. Simulated δ13C changes in the North Atlantic Deep Water region are again related to AMOC changes. Yet in regions bathed by Antarctic Bottom Water or Antarctic Intermediate Water, the δ13C evolution is driven by Southern Hemisphere source water δ13C changes, while in the Nordic Seas and the two major overflow regions it is driven by Northern Hemisphere source water δ13C changes. This shows that AMOC changes are not necessarily recorded by δ13C and stresses the need for combining both tracers in paleoclimate studies. A preliminary model‐data comparison for Last Interglacial flow speeds and δ13C changes in the Deep Western Boundary Current shows that this integrated approach is far from straightforward and currently inconclusive on the Last Interglacial AMOC evolution. Nonetheless, the approach yields potential for more direct and in‐depth model‐data comparisons of past AMOC changes.
Mammalian Embryo: Establishment of the Embryonic Axes
Authors: Srinivas Shankar 
Published: January 2015

Abstract

Owing to implantation and the requirement for extraembryonic tissues during mammalian embryogenesis, the development of the foetal axes is a relatively late event. Consequently, the definitive body axes of the organism are established in the founder tissue of the foetus well after polarised asymmetries have arisen in the conceptus. The anterior–posterior polarity of the organism has its origin in an extraembryonic tissue, the visceral endoderm, and there is evidence that the axes of the conceptus directly influence the orientation of the definitive body axes. Directional cell movements in the visceral endoderm help position the primitive streak, a structure that plays a key role in establishing the pattern of the primary body axis. Subsequently, asymmetries along the left–right axis are generated. As these are fundamental events that the remainder of embryonic development is predicated on, defects in these processes generally lead to embryos that fail to develop further.

Key Concepts

The mammalian embryo first generates structures and tissues that contribute to the placenta; therefore, there are various axes of asymmetry in the early conceptus that are not present in the final foetus.

There is a progressive increase in the degree of asymmetry in the pre‐implantation conceptus from an approximately spherically symmetrical zygote to radially symmetrical early blastocyst and finally bilaterally symmetrical late blastocyst.

The epiblast, which gives rise to the foetus, does not appear to have intrinsic axial information but receives axial patterning information from an extraembryonic tissue called the anterior visceral endoderm.

The anterior visceral endoderm defines the site of gastrulation by restricting the formation of the primitive streak in the epiblast.

The migratory movement of the anterior visceral endoderm is crucial to the proper orientation of the anterior–posterior axis.

A specialised structure called the node, located at the rostral end of the primitive streak, plays a central role not only in the organisation of the primary body axis but also in generating left–right asymmetries.