bluuebunny/crossref_metadata_2025 huggingface dataset:
Wellbore Stability Analysis Made Easy and Practical
Authors: Santarelli F. J. , Zaho S. , Burrafato G. , Zausa F. , Giacca D.
Published: April 2015

Recent years have seen many scientific and technical progress in the field of wellbore stability understanding. The main causes of instabilities have been identified, models developed and practical remedies proposed and often tried successfully in the field. Yet despite this scientific effort, drilling extra costs associated with wellbore instabilities remain very high. This in turn demonstrates that until now, scientific and technical progress have somehow failed to reach their final technico-economical objectives.

This paper shows that the main reason for such a state of affairs is the complexity of wellbore stability analysis which cannot be performed for every single well on a worldwide basis. Having identified this, Agip undertook a vast effort of field data back analysis in order to identify from historical records the best way to optimize its drilling planning, practice and post-evaluation procedures. The paper presents part of this effort and in particular the back analysis of four clusters drilled in Southern Italy -i.e. 38 wells in total. It then draws conclusions in terms of procedure optimization. Finally, it presents how the approach is used during the appraisal phase of a field in order to speed up the learning curve and hence significantly cut the development drilling costs.
Newly Applied BHA Elements Contribute Towards Mainstreaming of Coiled tubing Drilling Applications
Authors: Gleitman D. D. , Hardin J. R. , Hightower C. M. , Gantt L. L. , Smith B. E. , Upchurch E. R. , Smith M. B.
Published: April 2015

Coiled tubing drilling (CTD) is coming into the mainstream in a number of locations and applications, and the availability of improved BHA elements is a significant contributor in this regard. This paper describes BHA elements including a hydraulic orientcr and MWD system recently employed by ARCO in CTD operations, examines their capabilities, and provides a series of examples in which these tools were successfully employed.

The BHA elements formerly utilized in coiled tubing drilling have often not performed as well or as reliably as the industry has become accustomed to in conventional drilling operations.1 Principle concerns here include the overall ROP, attainment of timely survey and steering data, and directional control of the BHA. The BHA elements utilized in the recent operations represent an improvement in these critical functions.

The BHA orienter is a newly engineered, simple, hydraulically actuated device. Its performance attributes affecting overall ROP and directional control of the BHA are examined, including its speed of actuation, and its ability to change the BHA orientation while in a medium radius curve. The MWD system really represents a new application of an existing reliable system, with attributes that are especially important in the CTD environment. Modifications related to downsizing are examined, as well as relevant performance attributes including: steering data update rate; real time gamma log quality; mud pulse detection capability on coil in a range of drilling fluids; and reliability. The BHA is also looked at from an overall system perspective, including its integration with the coiled tubing and other equipment associated with the CTD operation.

As of this writing, ARCO Alaska, Inc. and THUMS Long Beach Co. (a wholly owned subsidiary of ARCO) have completed 16 CTD reentry sidetrack jobs utilizing these BHA elements in Alaska and Long Beach, California. Overall performance and reliability from these jobs are summarized. Additionally, specific cases are examined in greater detail, with these BHA elements contributing towards successful CTD window milling, medium radius curves, and laterals.
Mustard Cover Crops for Biomass Production and Weed Suppression in the Great Lakes Region
Authors: Björkman Thomas , Lowry Carolyn , Shail Joseph W. , Brainard Daniel C. , Anderson Daniel S. , Masiunas John B.
Published: April 2015

Short‐season cover cropping can be an important weed management tool. To optimize the use of mustard [Sinapis alba L. and Brassica juncea (L.) Czern.] in the Great Lakes region, we assessed planting time effects, mustard biomass production, and weed suppression during mustard growth and after incorporation. The study was conducted in Illinois, Michigan, and New York for spring and fall from 2010 to 2012. Mustard was sown every ∼10 d from mid‐March to early June for spring plantings and from early August to mid‐September for fall plantings. Spring mustard biomass, weed density, community composition, and dry biomass were collected at mustard flowering. Fall mustard biomass, weed density, and dry biomass were collected at season end. Spring mustard biomass ranged from <0.5 to 4 t ha−1. Early fall biomass ranged from 3 to 5.5 t ha−1, and was related to growing degree days (GDD) according to a logistic function. Weed biomass during mustard growth was reduced by at least 50% in 9 of 10 site‐years (90%) for fall‐planted mustard but only 15 of 31 site‐years (48%) in spring plantings. Weed suppression was independent of mustard biomass. The total number of weed seedlings emerging after mustard incorporation was not significantly reduced, but there was a species‐specific response, with a decrease in common lambsquarters (Chenopodium album L.) and grass emergence. The results permit a location‐specific recommendation to plant mustard cover crops 13 to 23 August in the southern Great Lakes Region, and no later than 1 to 10 September for adequate biomass production.
Meeting Global Food Needs: Realizing the Potential via Genetics × Environment × Management Interactions
Authors: Hatfield Jerry L. , Walthall Charles L.
Published: April 2015

Global food needs are projected to double by 2050 to feed the 9 billion people and the challenge presented to agriculture is whether this is feasible. These goals will be faced with an increasing variability in climate and more extremes in temperature and precipitation in all parts of the world and a decreasing land resource base in extent and quality. There are many challenges to be faced; however, focusing on the interactions of genetics × environment × management (G × E × M) offers the potential to feed the 9 billion. Understanding and quantifying yield gaps offer a framework to assess the progress, and the challenge will be to determine the most effective and efficient way of closing the yield gap by using water and nutrients more efficiently. The more feasible approach of increasing potential will be to increase the actual yields rather than increasing potential yield. Actual yield increases and overall productivity can come from management systems focused on increasing land productivity because our ability to expand the available land resources are not a viable option. Development of methods of screening genotypes for a variety of responses to combinations of environmental and management scenarios offers the potential pathway to developing a robust structure for G × E × M. We can meet this challenge; however, the paradigm of how we currently conduct research will not be rapid enough and we need to develop the transdisciplinary teams to represent each component of the G × E × M interaction.
Soil Water Retention Curve Description Using a Flexible Smooth Function
Authors: Prunty Lyle , Casey F. X. M.
Published: April 2015

Water retention curves (WRC) play an essential role in characterizing soil hydraulic behavior. Numerous mathematical functions have been explicitly developed for modeling the WRC, a very recent example being a cubic spline approach using virtual data points. This study presents use of WRC functions that transition smoothly between straight‐line asymptotes. We call them flexible functions. Flexible functions successfully represented a variety of WRCs, including some of rather high complexity. A reduction of root‐mean‐square error was often found in comparing flexible functions to other commonly used WRC functions. Integrations of the Mualem procedure for calculating relative hydraulic conductivity result in analytical expressions when using flexible functions as the WRC model. Conductivity calculated with these expressions agrees well with the RETC solution. Flexible functions are capable of representing dry regime behavior as well.
Preliminary Investigations of Effluent Drainage from Mining Heap Leach Facilities
Authors: Kampf Stephanie K. , Salazar Miguel , Tyler Scott W.
Published: April 2015

Long‐term infiltration and drainage through unsaturated metal mining waste poses the potential to transport toxic contaminants, such as arsenic, cyanide, and mercury, to the underlying groundwater. However, an almost complete lack of analysis of the long‐term infiltration rates through these wastes signficantly hampers quantitative assessment of the environmental impacts. This work synthesizes drainage data taken from regulatory reporting of gold and copper heap leach structures in the state of Nevada to investigate the magnitude of long‐term infiltration and the factors controlling infiltration. Because heap leach structures are lined, infiltration and drainage rates can be directly measured at a downstream point. Drainage rates following rinsing showed an exponential decline, and in three of the eight sites examined in this study, drainage reached a steady state derived from precipitation. The remaining five sites continued to show a very slow decline in drainage after as much as 57 mo of drainage. Estimated precipitation‐derived drainage ranged from 6 to 160 mm yr−1, which constituted recharge ranging from 2 to 23% of annual precipitation. At low precipitation sites, estimated recharge through heaps was higher than predicted by models used to estimate recharge in semiarid regions, and the highest recharge rates were calculated for heaps containing coarse textured ore. At higher precipitation sites, estimated recharge was lower than model predictions. Many of these sites had engineered soil and vegetation covers that successfully limited infiltration of moisture through the heaps. Water infiltration and drainage may be greater where the ratio of potential evapotranspiration to precipitation is low and where a high proportion of slope surface area is exposed, but the relationship between these variables and drainage could not be clearly defined based on the data in this study.
Dynamic Effect in the Capillary Pressure–Saturation Relationship and its Impacts on Unsaturated Flow
Authors: Hassanizadeh S. Majid , Celia Michael A. , Dahle Helge K.
Published: April 2015

Capillary pressure plays a central role in the description of water flow in unsaturated soils. While capillarity is ubiquitous in unsaturated analyses, the theoretical basis and practical implications of capillarity in soils remain poorly understood. In most traditional treatments of capillary pressure, it is defined as the difference between pressures of phases, in this case air and water, and is assumed to be a function of saturation. Recent theories have indicated that capillary pressure should be given a more general thermodynamic definition, and its functional dependence should be generalized to include dynamic effects. Experimental evidence has slowly accumulated in the past decades to support a more general description of capillary pressure that includes dynamic effects. A review of these experiments shows that the coefficient arising in the theoretical analysis can be estimated from the reported data. The calculated values range from 104 to 107 kg (m s)−1 In addition, recently developed pore‐scale models that simulate interface dynamics within a network of pores can also be used to estimate the appropriate dynamic coefficients. Analyses of experiments reported in the literature, and of simulations based on pore‐scale models, indicate a range of dynamic coefficients that spans about three orders of magnitude. To examine whether these coefficients have any practical effects on larger‐scale problems, continuum‐scale simulators may be constructed in which the dynamic effects are included. These simulators may then be run to determine the range of coefficients for which discernable effects occur. Results from such simulations indicate that measured values of dynamic coefficients are within one order of magnitude of those values that produce significant effects in field simulations. This indicates that dynamic effects may be important for some field situations, and numerical simulators for unsaturated flow should generally include the additional term(s) associated with dynamic capillary pressure.
Fluid Flow, Heat Transfer, and Solute Transport at Nuclear Waste Storage Tanks in the Hanford Vadose Zone
Authors: Pruess Karsten , Yabusaki Steve , Steefel Carl , Lichtner Peter
Published: April 2015

At the Hanford Site, highly radioactive and chemically aggressive waste fluids have leaked from underground storage tanks into the vadose zone. This paper addresses hydrogeological issues at the 241‐SX tank farm, especially focusing on Tank SX‐108, which is one of the highest heat load, supernate density and ionic strength tanks at Hanford and a known leaker. The behavior of contaminants in the unsaturated zone near SX‐108 is determined by an interplay of multiphase fluid flow and heat transfer processes with reactive chemical transport in a complex geological setting. Numerical simulation studies were performed to obtain a better understanding of mass and energy transport in the unique hydrogeologic system created by the SX tank farm. Problem parameters are patterned after conditions at Tank SX‐108, and measured data were used whenever possible. Borrowing from techniques developed in geothermal and petroleum reservoir engineering, our simulations feature a comprehensive description of multiphase processes, including boiling and condensation phenomena, and precipitation and dissolution of solids. We find that the thermal perturbation from the tank causes large‐scale redistribution of moisture and alters water seepage patterns. During periods of high heat load, fluid and heat flow near the tank are dominated by vapor–liquid counterflow (heat pipe), which provides a much more efficient mechanism than heat conduction for dissipating tank heat. The heat pipe mechanism is also very effective in concentrating dissolved solids near the heat source, where salts may precipitate even if they were only present in small concentrations in ambient fluids. Tank leaks that released aqueous fluids of high ionic strength into the vadose zone were also modeled. The heat load causes formation dry‐out beneath the tank, which is accompanied by precipitation of solutes. These may become remobilized at a later time when tank temperatures decline and previously dried out regions are rewetted. Simulated temperature and moisture distributions compare well with borehole measurements performed in 2000. The temperature maximum observed beneath Tank SX‐108 can be explained from past thermal history of the tank; it is not necessary to invoke heat generation from leaked radioactive contaminants. A novel composite medium model is used to explore effects of moisture tension–dependent anisotropy, which is shown to have important impacts on fluid flow and solute transport in the Hanford sediments.
Kilometer‐Scale Rapid Transport of Naphthalene Sulfonate Tracer in the Unsaturated Zone at the Idaho National Engineering and Environmental Laboratory
Authors: Nimmo John R. , Perkins Kim S. , Rose Peter E. , Rousseau Joseph P. , Orr Brennon R. , Twining Brian V. , Anderson Steven R.
Published: April 2015

To investigate possible long‐range flow paths through the interbedded basalts and sediments of a 200‐m‐thick unsaturated zone, we applied a chemical tracer to seasonally filled infiltration ponds on the Snake River Plain in Idaho. This site is near the Subsurface Disposal Area for radioactive and other hazardous waste at the Idaho National Engineering and Environmental Laboratory. Within 4 mo, we detected tracer in one of 13 sampled aquifer wells, and in eight of 11 sampled perched‐water wells as far as 1.3 km away. These detections show that (i) low‐permeability layers in the unsaturated zone divert some flow horizontally, but do not prevent rapid transport to the aquifer; (ii) horizontal convective transport rates within the unsaturated zone may exceed 14 m d−1, perhaps through essentially saturated basalt fractures, tension cracks, lava tubes, or rubble zones; and (iii) some perched water beneath the Subsurface Disposal Area derives from episodic surface water more than 1 km away. Such rapid and far‐reaching flow may be common throughout the Snake River Plain, and possibly occurs in other locations that have a geologically complex unsaturated zone and comparable sources of infiltrating water.
Review and Analysis of Chlorinated Solvent Dense Nonaqueous Phase Liquid Distributions in Five Sandy Aquifers
Authors: Parker B. L. , Cherry J. A. , Chapman S. W. , Guilbeault M. A.
Published: April 2015

To select and design effective remedial measures for dense, nonaqueous phase liquid (DNAPL) source zones, better understanding of the architecture of these zones is needed. In this study, a suite of investigative techniques was applied to perform detailed vertical delineation of chlorinated‐solvent source zones in sand aquifers at five contaminated industrial sites (two in Connecticut, and one each in Florida, New Hampshire, and Ontario). The DNAPL occurs in the middle of the aquifers at three of the sites and at or near the bottom at the other two. The DNAPL entered the subsurface at these sites decades ago, and therefore the DNAPL zones have aged due to groundwater dissolution. The suite of investigative techniques was used to perform profile sampling using direct‐push methods, in which depth‐discrete soil and groundwater samples were taken with extremely close vertical spacing. The sampling included methods to distinguish between free‐product and residual DNAPL at two of the sites. At each location where DNAPL was found, the DNAPL occurred in one or a few thin layers, generally between 1 and 30 cm thick. These layers were positioned within distinct grain‐size zones, or at contacts between sedimentological layers. In some cases, the DNAPL layers have no apparent textural association. For any particular sampling hole to have a high probability of finding such layers, continuous cores must be collected and sampling of these cores must be done at very close vertical spacing (5 cm or less). Free‐product DNAPL occurrences in conventional wells at three of the sites indicated, misleadingly, much greater DNAPL layer thicknesses than actual, and in one case, the conventional well may have caused short‐circuiting of DNAPL from the middle to the bottom of the aquifer. Although all of the DNAPL source zones are comprised of only sporadic, thin DNAPL layers representing little total mass, these source zones are the cause of high‐concentration dissolved plumes down gradient.
Estimating Soil Hydraulic Parameters of a Field Drainage Experiment Using Inverse Techniques
Authors: Zhang Z. Fred , Ward Andy L. , Gee Glendon W.
Published: April 2015

Accurate assessment of water flow and contaminant transport in unsaturated porous media at the field scale is often hindered by difficulties associated with obtaining reliable estimates of soil hydraulic properties. The unsteady drainage‐flux method is one of the commonly used methods to measure in situ unsaturated hydraulic properties of soils. However, the properties obtained by this method using instantaneous profile data analysis may not be the best estimation of actual values of hydraulic properties. We present an improved analysis of the data from drainage experiments using inverse modeling, which uses nonlinear regression methods to estimate hydraulic parameters. Parameter identifiability is evaluated through sensitivity and uniqueness analyses. We used the combination of the inverse modeling program, UCODE, with the flow simulator, STOMP, for inverse modeling. Applying the inverse method to a field drainage experiment in sandy soil showed that all the van Genuchten (1980) hydraulic parameters could be estimated uniquely when both water content (θ) and pressure head (h) data were used. The parameter estimates by inverse technique using both θ and h data simulated the flow better than the parameter values obtained by the conventional instantaneous‐profile analysis method. After the spatial and temporal sensitivities were analyzed, a more rational experimental design was recommended.
Physical Processes Affecting Natural Depletion of Volatile Chemicals in Soil and Groundwater
Authors: Parker Jack C.
Published: April 2015

A Fickian model is described for dispersive vapor transport due to “pumping” induced by barometric pressure fluctuations and periodic water table fluctuations. The approach is appropriate for time scales that are large relative to the period of induced airflow variations. Comparisons of the magnitude of dispersive fluxes with those due solely to molecular diffusion indicated that dispersive vapor transport becomes increasingly important as soil porosity decreases and as the depth to groundwater and the contaminant source increases. For soils with low air‐filled porosity, barometric pumping is likely to dominate transport even for shallow soils. Barometric pumping may predominate for soils with moderate to high air‐filled porosity with deeper groundwater (>5–15 m). Water table pumping is predicted to predominate over diffusion only for high‐frequency fluctuations, such as tidal conditions. A steady‐state model for contaminant volatilization from groundwater is presented that considers diffusive and dispersive vapor transport, unsaturated zone aqueous phase advection, and dispersive mixing in groundwater, yielding an apparent first‐order decay coefficient with respect to groundwater. Predicted volatilization coefficients for perchloroethene (PCE) range from <0.001 to >0.02 d−1 for various soil conditions and groundwater depths. Highest values are predicted for the most permeable soils. Volatilization rates are predicted to decrease with depth up to a point at which dispersive fluxes dominate over diffusion and then to increase to the extent that barometric pressure fluctuations propagate to greater depths. Vertical mixing within the saturated zone has a significant influence on volatilization from groundwater. Simple moving front and mixing cell models are presented to estimate depletion rates of soil contamination due to volatilization and leaching. Results indicate that natural depletion of residual soil NAPL may take many decades and is markedly influenced by soil conditions, hydraulic flux, and contaminant properties.
Experimental and Numerical Investigation of Flow Phenomena in Nonisothermal, Variably Saturated Bentonite–Crushed Rock Mixtures
Authors: Engelhardt Irina , Finsterle Stefan , Hofstee Cor
Published: April 2015

Mixtures of sodium bentonite and crushed rock are being examined as components of the engineered barrier system in a geologic repository of high‐level nuclear waste. Laboratory experiments were performed to determine the thermal and unsaturated hydraulic properties of bentonite–crushed diorite mixtures. Water‐retention curves were obtained from conventional pressure cell and evaporation experiments. In addition, transient data from heating and gas injection experiments on laboratory columns were analyzed using inverse modeling techniques. Measured pressures, temperatures, and drained‐water volumes were jointly inverted to estimate absolute permeability, thermal conductivity, specific heat, and capillary strength parameters. Simultaneous matching of all available data—specifically the gas breakthrough at the top of the column—proved difficult, pointing toward aspects of the experimental design and the conceptual model that need to be refined. The analysis of sensitivity coefficients and the correlation structure of the parameters revealed the importance of accurately capturing coupled thermal hydrological processes within the column as well as the details of the experimental apparatus, such as heat losses and storage of water and gas in the measuring burette. The parameters estimated using different experimental and analytical procedures were consistent with one another, providing backfill material properties useful for the simulation of gas‐ and heat‐generating nuclear waste repositories.
Constant Capacitance Model Computation of Boron Speciation for Varying Soil Water Content
Authors: Vaughan P. J. , Suarez D. L.
Published: April 2015

This work considered the aqueous speciation of B between a soil solution containing B and the tetrahedral surface B species (SH3BOH−4 during drying of the soil. The aqueous B species were boric acid (H3BO3) and the borate anion B OH−4 A computer program was written to calculate solution speciation of major ions using a matrix‐type numerical solution including cation exchange and dissolution–precipitation of calcite. The B speciation was calculated separately but utilized the H+ concentration as determined in the major ion speciation. Numerical simulations of soil drying were performed for 20 hypothetical soil textures with clay contents ranging from 10 to 60% and three solution compositions representing saline, saline‐sodic, and sodic soils. The effective Kd (SH3BOH−4/total solution B) decreased with gravimetric water content (θg) for the range θg = 1.5 to 0.05. A decrease in H+ concentration caused decreasing Kd consistent with earlier experimental work showing decreasing fractional adsorbed B with decreasing pH in the range 7 to 9. Kd varied from 2.5 to 4.7 at θg = 1.5 because of variation of the equilibrium constants in the constant capacitance model (K− and K+) with varying soil texture. Kd increased with increasing sodicity of the soil water. An application of this program would be prediction of adsorbed and solution B concentrations at field water content on the basis of experimental determinations of adsorbed and solution B concentration for saturated paste extracts. Such predictions would be useful to generate initial conditions for solute transport modeling and for determining whether solution B concentrations at field water contents would be beneficial or harmful to plants.
Unstable Flow during Redistribution in Homogeneous Soil
Authors: Wang Zhi , Tuli Atac , Jury William A.
Published: April 2015

Two‐ and three‐dimensional laboratory experiments were conducted in a large 1 by 1 m2 Hele–Shaw cell and a 10‐cm cylinder column to study the stability of the redistribution process in a uniformly packed porous medium of coarse sand. Our results demonstrate that fingers form and propagate rapidly as soon as infiltration stops when the soil is initially dry, but form more slowly and are larger when the soil is wet. Finger widths ranged from about 4.5 cm when the soil was dry to 17 cm when the soil was very wet, and the fraction of the cross‐sectional area occupied by fingers also increased (from 36 to 66%). Finger velocities declined with time in all studies, with averages ranging from 3.6 to 9.6 cm min−1. We demonstrated that ponded infiltration was stable and uniform in our system, so that the fingering we observed was not due to soil heterogeneity. The porous medium retained a memory of the fingers formed in the first experiment, so fingers formed in subsequent redistribution cycles followed the old finger paths, even after 28 d had elapsed. Fingers provide channels for rapid drainage of previously infiltrated water, especially when the soil ahead of the front is dry. Our findings clearly contradict predictions made by the Richards equation, which calculates stable flow during redistribution in homogeneous soil.
Evaluation of the WAVE Model for Predicting Nitrate Leaching for Two Contrasted Soil and Climate Conditions
Authors: Duwig Céline , Normand Béatrice , Vauclin Michel , Vachaud Georges , Green Steven R. , Becquer Thierry
Published: April 2015

The integrated soil–crop–atmosphere model Water and Agrochemicals in the Vadose Environment (WAVE) (Vanclooster et al., 1995) was evaluated for two contrasted sets of data. One was from the tropical climate and ferrallitic soil conditions that exist in Maré Island, in New Caledonia. The other was from a glacial terrace under the continental climate of La Côte Saint‐André (Isère) in France. Water and NO3 concentrations and fluxes were monitored during three consecutive years at instrumented sites with different surface covers (maize [Zea mays L.] or bare soil) or amount of applied fertilizer. The comprehensive set of measurements allowed us to evaluate the prediction capabilities of the WAVE model. Several parameters were determined independently, while others were adjusted on the basis of simulations for the wettest year at Maré and an average hydrological year at La Côte Saint‐André. A stepwise approach was used to calibrate these parameters by sequentially integrating each individual model component. A screening sensitivity analysis was performed to address the most critical parameters. The predictive ability of the model was evaluated by comparing simulated and measured states variables and water and NO3 fluxes using two different years of data obtained at the same sites. For both sites, the model gave the best results for wet conditions, which actually posed the most critical problems in terms of groundwater pollution under our specific conditions. However, the model was used beyond its capacity as both soils had specificities for which the model was not designed. Overall, WAVE gave quite good predictions, but further studies are needed to fully evaluate WAVE with its crop growth model, SUCROS.
Soil Aggregate Structure Effects on Dielectric Permittivity of an Andisol Measured by Time Domain Reflectometry
Authors: Miyamoto Teruhito , Annaka Takeyuki , Chikushi Jiro
Published: April 2015

Various types of soil physical properties are affected by texture and structure. Our objective was to determine aggregate structure effect on the soil dielectric property of an Andisol measured by time domain reflectometry (TDR). The relationships between volumetric water content (θ) and dielectric permittivity (ε) for both a wet‐sieved aggregate and its crushed sample were examined and compared. In the θ–ε relationship for 0.1‐ to 2.0‐mm‐diam. wet‐sieved aggregates, the gradient of the θ–ε curve moderately changed at a volumetric water content (critical water content), although this property disappeared when we crushed the aggregate structure. Furthermore, the critical value corresponded to the water content of the plateau in a bimodal‐type water retention curve. We suggest that effects of aggregate structure on a soil's dielectric property are involved in the aggregate sizes, the configuration of water in aggregates, the processes of water filling in intra‐ and interaggregate pores, and the low ε value of bound water adsorbed on soil surfaces.
Business process model and notation: The current state of affairs
Authors: Kocbek Mateja , Jost Gregor , Hericko Marjan , Polancic Gregor
Published: April 2015

Context: With business process modelling, companies and organizations can
gain explicit control over their processes. Currently, there are many
notations in the area of business process modelling, where Business Process
Model and Notation (BPMN) is denoted as the de facto standard. Aims: The aim
of this research is to provide the state-of-the-art results addressing the
acceptance of BPMN, while also examining the purposes of its usage.
Furthermore, the advantages, disadvantages and other interests related to
BPMN were also investigated. Method: To achieve these objectives, a
Systematic Literature Review (SLR) and a semantic examination of articles?
citations was conducted. Results: After completing SLR, out of a total of 852
articles, 31 were deemed relevant. The majority of the articles analyzed the
notation and compared it with other modelling techniques. The remainder
evaluated general aspects of the notation, e.g. history and versions of the
standard, usage of the notation or tools. Conclusion: Our findings
demonstrate that there are empirical insights about the level of BPMN
acceptance. They suggest that BPMN is still widely perceived as the de facto
standard in the process modelling domain and its usage is everincreasing.
However, many studies report that only a limited set of elements are commonly
used and to this end, several extensions were proposed. The main purpose of
BPMN remains the description of business processes.
Voluntary Disclosures via Social Media and the Role of Comments
Authors: Trinkle Brad S. , Crossler Robert E. , Bélanger France
Published: April 2015

The Securities and Exchange Commission (SEC) has recently expanded the communication channels available for management when it determined that personal social media pages are recognized channels for financial disclosures, provided Reg FD and the 2008 Guidance are correctly applied. However, social media channels are more widely available to investors, both nonprofessional and sophisticated, and allow for interaction between users via postings and comments. The opinions of others, as expressed in their comments on social media, may influence investors' perception of the news in a manner that is beyond that of the traditional disclosures envisioned by the SEC. This research explores this issue by examining the influence of disclosures and attached comments via social media on nonprofessional investors' perceptions of the news, valuation judgments, and perceptions of management's credibility. Grounded in the herding and majority influence theories, the research hypotheses are tested using a between-subjects experimental design. Results indicate that the attached comments shared via social media influence the participants' perceptions and reactions to the news.
A Novel CCK-8/GLP-1 Hybrid Peptide Exhibiting Prominent Insulinotropic, Glucose-Lowering, and Satiety Actions With Significant Therapeutic Potential in High-Fat–Fed Mice
Authors: Irwin Nigel , Pathak Varun , Flatt Peter R.
Published: April 2015

Glucagon-like peptide-1 (GLP-1) and cholecystokinin (CCK) exert important complementary beneficial metabolic effects. This study assessed the biological actions and therapeutic utility of a novel (pGlu-Gln)-CCK-8/exendin-4 hybrid peptide compared with the stable GLP-1 and CCK mimetics exendin-4 and (pGlu-Gln)-CCK-8, respectively. All peptides significantly enhanced in vitro insulin secretion. Administration of the peptides, except (pGlu-Gln)-CCK-8 alone, in combination with glucose significantly lowered plasma glucose and increased plasma insulin in mice. All treatments elicited appetite-suppressive effects. Twice-daily administration of the novel (pGlu-Gln)-CCK-8/exendin-4 hybrid, (pGlu-Gln)-CCK-8 alone, or (pGlu-Gln)-CCK-8 in combination with exendin-4 for 21 days to high-fat–fed mice significantly decreased energy intake, body weight, and circulating plasma glucose. HbA1c was reduced in the (pGlu-Gln)-CCK-8/exendin-4 hybrid and combined parent peptide treatment groups. Glucose tolerance and insulin sensitivity also were improved by all treatment modalities. Interestingly, locomotor activity was decreased in the hybrid peptide group, and these mice also exhibited reductions in circulating triglyceride and cholesterol levels. Pancreatic islet number and area, as well β-cell area and insulinotropic responsiveness, were dramatically improved by all treatments. These studies highlight the clear potential of dual activation of GLP-1 and CCK1 receptors for the treatment of type 2 diabetes.
Successful Management of Severe Unilateral Lower Extremity Lymphedema in an Outpatient Setting
Authors: Leard Teresa , Barrett Carrie
Published: April 2015

Background and Purpose

Non–cancer-related lymphedema is frequently unrecognized until it has advanced and, therefore, presents substantial management challenges. Treatment for lymphedema reflects cancer research and not the distinct complexities of non–cancer-related lymphedema. This case report describes an outpatient intervention for a patient with non–cancer-related unilateral lower extremity lymphedema.

Case Description

The patient was a 42-year-old woman who was morbidly obese and had left lower extremity chronic stage III lymphedema. Massive disfiguring lymphedema of her lower leg caused chronic wounds, pain, difficulty ambulating, and the inability to lift her leg in transfers. The patient received complete decongestive therapy (CDT) in an outpatient setting.

Outcomes

The volume of the patient's leg decreased more than 66%, so that her massive lower leg was transformed to nearly the same size as her unaffected limb. Proper compression management restored independent transfers and pain-free ambulation.

Discussion

Delayed diagnosis and treatment of non–cancer-related lymphedema result in increased severity and impaired mobility, making this a unique, complex condition requiring modifications to CDT in the outpatient setting. This case report demonstrates successful outpatient treatment of a patient with severe unilateral lower extremity lymphedema associated with large wounds and impaired mobility using CDT that was modified to accommodate her complex medical status, transportation barriers, and health insurance availability. Following 23 weeks of physical therapist interventions, the patient's affected lower extremity was the same size as the unaffected lower extremity, and she was independent in ambulation and stair climbing.
The Theory and Practice of Culturally Relevant Education
Authors: Aronson Brittany , Laughter Judson
Published: April 2015

Many teachers and educational researchers have claimed to adopt tenets of culturally relevant education (CRE). However, recent work describes how standardized curricula and testing have marginalized CRE in educational reform discourses. In this synthesis of research, we sought examples of research connecting CRE to positive student outcomes across content areas. It is our hope that this synthesis will be a reference useful to educational researchers, parents, teachers, and education leaders wanting to reframe public debates in education away from neoliberal individualism, whether in a specific content classroom or in a broader educational community.
Estimating the Difference Between Published and Unpublished Effect Sizes
Authors: Polanin Joshua R. , Tanner-Smith Emily E. , Hennessy Emily A.
Published: April 2015

Practitioners and policymakers rely on meta-analyses to inform decision making around the allocation of resources to individuals and organizations. It is therefore paramount to consider the validity of these results. A well-documented threat to the validity of research synthesis results is the presence of publication bias, a phenomenon where studies with large and/or statistically significant effects, relative to studies with small or null effects, are more likely to be published. We investigated this phenomenon empirically by reviewing meta-analyses published in top-tier journals between 1986 and 2013 that quantified the difference between effect sizes from published and unpublished research. We reviewed 383 meta-analyses of which 81 had sufficient information to calculate an effect size. Results indicated that published studies yielded larger effect sizes than those from unpublished studies ([Formula: see text] = 0.18, 95% confidence interval [0.10, 0.25]). Moderator analyses revealed that the difference was larger in meta-analyses that included a wide range of unpublished literature. We conclude that intervention researchers require continued support to publish null findings and that meta-analyses should include unpublished studies to mitigate the potential bias from publication status.
Middle School Math Acceleration and Equitable Access to Eighth-Grade Algebra
Authors: Dougherty Shaun M. , Goodman Joshua S. , Hill Darryl V. , Litke Erica G. , Page Lindsay C.
Published: April 2015

Taking algebra by eighth grade is considered an important milestone on the pathway to college readiness. We highlight a collaboration to investigate one district’s effort to increase middle school algebra course-taking. In 2010, the Wake County Public Schools began assigning middle school students to accelerated math and eighth-grade algebra based on a defined prior achievement metric. This policy reduced the relationship between course assignment and student characteristics such as income and race/ethnicity, while increasing its relationship to academic skill. The policy increased the share of students on track for algebra by eighth grade. Students placed in accelerated math were exposed to higher-skilled peers but larger classes. Future work will assess impacts on subsequent achievement and course-taking outcomes.
Large Primary Tuberculous Psoas Abscess in an HIV Patient – A Case Report
Authors: Rakesh TP , Kidangazhiathmana A , Jyothish K , Amrutha PC , Satheeshbabu TV
Published: April 2015

Tuberculosis (TB) remains as one of the leading opportunistic infection in patients with Human immunodefficiency virus (HIV) infection in developing countries. Here we report a case of huge primary psoas abscess of tubercular origin in an HIV patient who presented with hip pain and limping. Psoas sign was evident on examination and CT scan of abdomen revealed a large iliopsoas abscess extending from abdomen to upper part of thigh. Patient underwent percutaneous drainage of abscess and improved with anti-tuberculous drugs while continuing anti-retroviral therapy.DOI: http://dx.doi.org/10.3126/saarctb.v11i2.12437SAARC J TUBER LUNG DIS HIV/AIDS, 2014;XI(2), Page: 34-36
Use of Simulation Learning Experiences in Physical Therapy Entry-to-Practice Curricula: A Systematic Review
Authors: Mori Brenda , Carnahan Heather , Herold Jodi
Published: April 2015

Purpose: To review the literature on simulation-based learning experiences and to examine their potential to have a positive impact on physiotherapy (PT) learners' knowledge, skills, and attitudes in entry-to-practice curricula. Method: A systematic literature search was conducted in the MEDLINE, CINAHL, Embase Classic+Embase, Scopus, and Web of Science databases, using keywords such as physical therapy, simulation, education, and students. Results: A total of 820 abstracts were screened, and 23 articles were included in the systematic review. While there were few randomized controlled trials with validated outcome measures, some discoveries about simulation can positively affect the design of the PT entry-to-practice curricula. Using simulators to provide specific output feedback can help students learn specific skills. Computer simulations can also augment students' learning experience. Human simulation experiences in managing the acute patient in the ICU are well received by students, positively influence their confidence, and decrease their anxiety. There is evidence that simulated learning environments can replace a portion of a full-time 4-week clinical rotation without impairing learning. Conclusions: Simulation-based learning activities are being effectively incorporated into PT curricula. More rigorously designed experimental studies that include a cost–benefit analysis are necessary to help curriculum developers make informed choices in curriculum design.
Three-dimensional digital projection in neurosurgical education: technical note
Authors: Martins Carolina , Ribas Eduardo Carvalhal , Rhoton Albert L. , Ribas Guilherme Carvalhal
Published: April 2015

Three-dimensional images have become an important tool in teaching surgical anatomy, and its didactic power is enhanced when combined with 3D surgical images and videos. This paper describes the method used by the last author (G.C.R.) since 2002 to project 3D anatomical and surgical images using a computer source. Projecting 3D images requires the superposition of 2 similar but slightly different images of the same object. The set of images, one mimicking the view of the left eye and the other mimicking the view of the right eye, constitute the stereoscopic pair and can be processed using anaglyphic or horizontal-vertical polarization of light for individual use or presentation to larger audiences. Classically, 3D projection could be obtained by using a double set of slides, projected through 2 slide projectors, each of them equipped with complementary filters, shooting over a medium that keeps light polarized (a silver screen) and having the audience wear appropriate glasses. More recently, a digital method of 3D projection has been perfected. In this method, a personal computer is used as the source of the images, which are arranged in a Microsoft PowerPoint presentation. A beam splitter device is used to connect the computer source to 2 digital, portable projectors. Filters, a silver screen, and glasses are used, similar to the classic method. Among other advantages, this method brings flexibility to 3D presentations by allowing the combination of 3D anatomical and surgical still images and videos. It eliminates the need for using film and film developing, lowering the costs of the process. In using small, powerful digital projectors, this method substitutes for the previous technology, without incurring a loss of quality, and enhances portability.
Radiosurgery for temporal lobe arteriovenous malformations: effect of temporal location on seizure outcomes
Authors: Ding Dale , Quigg Mark , Starke Robert M. , Xu Zhiyuan , Yen Chun-Po , Przybylowski Colin J. , Dodson Blair K. , Sheehan Jason P.
Published: April 2015

OBJECT

The temporal lobe is particularly susceptible to epileptogenesis. However, the routine use of anticonvulsant therapy is not implemented in temporal lobe AVM patients without seizures at presentation. The goals of this case-control study were to determine the radiosurgical outcomes for temporal lobe AVMs and to define the effect of temporal lobe location on postradiosurgery AVM seizure outcomes.

METHODS

From a database of approximately 1400 patients, the authors generated a case cohort from patients with temporal lobe AVMs with at least 2 years follow-up or obliteration. A control cohort with similar baseline AVM characteristics was generated, blinded to outcome, from patients with non-temporal, cortical AVMs. They evaluated the rates and predictors of seizure freedom or decreased seizure frequency in patients with seizures or de novo seizures in those without seizures.

RESULTS

A total of 175 temporal lobe AVMs were identified based on the inclusion criteria. Seizure was the presenting symptom in 38% of patients. The median AVM volume was 3.3 cm3, and the Spetzler-Martin grade was III or higher in 39% of cases. The median radiosurgical prescription dose was 22 Gy. At a median clinical follow-up of 73 months, the rates of seizure control and de novo seizures were 62% and 2%, respectively. Prior embolization (p = 0.023) and lower radiosurgical dose (p = 0.027) were significant predictors of seizure control. Neither temporal lobe location (p = 0.187) nor obliteration (p = 0.522) affected seizure outcomes. The cumulative obliteration rate was 63%, which was significantly higher in patients without seizures at presentation (p = 0.046). The rates of symptomatic and permanent radiation-induced changes were 3% and 1%, respectively. The annual risk of postradiosurgery hemorrhage was 1.3%.

CONCLUSIONS

Radiosurgery is an effective treatment for temporal lobe AVMs. Furthermore, radiosurgery is protective against seizure progression in patients with temporal lobe AVM–associated seizures. Temporal lobe location does not affect radiosurgery-induced seizure control. The low risk of new-onset seizures in patients with temporal or extratemporal AVMs does not seem to warrant prophylactic use of anticonvulsants.