bluuebunny/crossref_metadata_2025 huggingface dataset:
Monitoring and Prediction of Cleanup Production During Sampling
Authors: Zazovsky Alexander
Published: February 2008

A novel concept for cleanup prediction during sampling is proposed. This concept shifts focus to the early phase of cleanup, allowing for early predictions of pumpout time or produced volume using optical fluid analysis logs versus given contamination targets. The early phase of cleanup potentially provides a great deal of information to be used in prediction of cleanup, because this phase is strongly affected by both the local flow pattern and the contamination transport and deals with a larger range of optical density variation.

A new approach to cleanup prediction is based on a truly 3D model of flow and contamination transport to the probe production area at the wellbore wall covered by mudcake. This model better captures the initial phase of cleanup than the conventional spherical flow model, which incorporates axisymmetrical contamination transport to a small production sphere located at the wellbore axis.

The new model provides the signature of 3D contamination transport on cleanup dynamics, which is controlled by the ratio of invasion depth to wellbore radius. The analysis of new problem solutions reveals new details of cleanup evolution. In particular, the transition from a predominantly circumferential regime of cleanup to a predominantly vertical cleanup has a distinctive signature that can be used in cleanup progress monitoring and the reconstruction of initial invasion depth.

Examples of sampling job data processing that support the new concept are provided. They indicate that decent estimates of pumpout volumes can be obtained 3 to 5 times earlier using the new approach.
New, Highly Effective Asphaltene Removal System With Favorable HSE Characteristics
Authors: Frost K. A. , Daussin R. D. , van Domelen M. S.
Published: February 2008

Paraffin and asphaltene problems can significantly reduce well profitability, causing troublesome operational issues, damaging formations, and decreasing production. Although often mentioned together, paraffin and asphaltene are distinctly different in their composition and behavior and different remediation solutions are required. In comparison, asphaltene deposition and removal is much more problematic than paraffin deposition and removal. The most common asphaltene removal techniques use xylene or xylene mixtures, which typically have limited effectiveness in addition to undesirable health, safety, and environmental characteristics.

This paper describes laboratory investigation of alternative solvent systems for removal of asphaltene deposits. Theoretical solvency parameter comparison based upon methods developed by Hildebrand and Hansen allowed solvents and cosolvents to be screened. The problem of formation wettability was addressed through the use of water-wetting surfactants. Finally, it was discovered that the primary solvent and cosolvent(s) could be dispersed in water yielding a water/aromatic solvent mixture that would not only effectively dissolve and disperse asphaltene, but also leave the formation in a water-wet state to delay production decline.

The new water-based asphaltene removal system was first applied in southern Europe in 2005. Since then, the system has been optimized for broader global operations whilst maintaining the favorable HS&E characteristics of the initial development. The system is unique as it provides a high-flashpoint water/solvent mixture with solvency power often greater than xylene and the additional benefit of leaving the formation strongly water-wet.
Concentric Annular Packing System Successfully Frac Packs Longest, Highly Deviated Intervals at Highest Record Treatment Rate Attempted Worldwide: Angola Case History
Authors: Lemesnager Fabien , Gavalda Jean , Chassagne Alain , Cortier Alexandre , Ranjeva Jean-Michel
Published: February 2008

Total E&P Angola operates the deep offshore ROSA field on Block 17. On the fifth development well in the field. Two zones in the Oligocene sandy layers are transversed at a well deviation of 48° and required the implementation of the stacked frac-pack technique. The perforated length of zones was approximately 118 ft and 213 ft.

Multiple fracture initiation and early screen out were expected, requiring consideration for an enhanced frac–packing method. In order to facilitate placement reliability, a concentric annular packing system was chosen to limit slurry bridging during placement in combination with an aggressive pumping design (25 bbl/min for the lower zone and 32 bbl/min for the upper zone). This paper will discuss the system used for successful frac packing and how it provided alternate paths for the slurry flow when a bridging occurred while keeping the same high flow rate.

Data collected on the two zones during treatment have shown that early annular bridging had occurred during slurry placement, but the system had successfully created a high-velocity flow path with minimal pressure drop to bypass the bridge. Once the bridge was bypassed, the full flow area was again used, minimizing turbulence and potential for damaging screens.

The paper will describe:

The target zones The concentric annular packing system design Integration of the concentric system in the dual stacked frac packs architecture Hole pattern design and velocity calculations in shroud orifices The service tool design for stack frac-packs Pumping treatment analysis Observations gathered during the job How technique and job-treatment design versus use of a regular frac-pack system or other alternate-path systems was justified.

Although alternate path technique has been used in frac-packing more than 30 times globally, the stack frac-pack performed on this case history well (WELL-5) holds the record for being the longest treated length, steepest deviation, and highest pumping rate ever attempted thanks to the concentric annular packing system originally designed for the horizontal gravel pack completions.

High completion efficiency was achieved. Productivity data are provided (skin, PLT, etc).
Surveillance and Diagnostics of Permanent Bottomhole Gauge Data Coupled with Geomechanical Modeling to Identify Sources of Formation Damage
Authors: Holicek R. A. , Adachi J. , Viloria L. A. , Mese A. I. , Traore Y. , Singh A. P. , Hanssen R.
Published: February 2008

With increasing availability of real-time downhole measurements in completions, more and more uses of these data are evolving. A deepwater field in the Gulf Of Mexico (GOM) consisting of numerous wells with permanent bottomhole gauges has been on a surveillance and diagnostic program for over 3 years. Pressure transient analysis of shut-ins give key performance indicators (KPIs) such as permeability-height (kh), skin (s) and current average reservoir pressure (Pave); the KPIs are summarized on a quarterly basis and compared with historical trends to check well performance. For the fields studied, the KPIs have proved valuable not only for production monitoring, but also as an investigative tool for larger-scale problems such as compaction, subsidence, depletion, and fines migration. This paper summarizes case histories from two fields where reduction in kh over time, and increasing skin over time led to a more in-depth study of the reservoir geomechanics. The geomechanical characterization of the reservoir allows for further insight into the behavior, increased knowledge of the production history, and allows for estimation of subsidence and compaction effects during future pressure transient tests.
Evaluation of Refracure Reorientation in Both Laboratory and Field Scales
Authors: Liu He , Lan Zhongxiao , Zhang Guoliang , Hou Feng , He Xiuqing , Liu Xinghui
Published: February 2008

Most tight oil reservoirs need to be hydraulically fractured before putting into production. Refracure is a necessary and efficient way to control production decline after first fracturing treatments. It has been recognized that reorientation of propped refracure treatments can contact with undepleted reservoir areas and that refracure reorientation is one of the main mechanisms for production enhancement.

In this paper, laboratory tests for fracture reorientation were investigated. Case histories of refracure treatments and tiltmeter mapping results were discussed. All the fracture treatments included a novel design technique of pumping paraffin balls approximately half way through the propped treatment in an attempt to initiate new fracture growth through different a perforation interval or in a different orientation. Tiltmeter mapping results indicated that fracture reorientation occurred for the majority of these refracure treatments studied. Case histories involved two tight oil reservoirs in the Daqing oilfield, China. More significant post-frac production improvements were observed for the refracure treatments with fracture reorientation.
Smart Mud Filtrate: An Engineered Solution To Minimize Near-Wellbore Formation Damage Due to Kaolinite Mobilization Laboratory and Field Experience–Oseberg Sør
Authors: Watson R. B. , Viste P. , Kaageson-Loe N. , Fleming N. , Mathisen A. M. , Ramstad K.
Published: February 2008

Numerous papers have been published on the influence that kaolinite mobilization has on well productivity. However, less attention has been directed toward identifying methods to minimize the detrimental impact of this mobilization. This paper will detail the pro-active approach that the authors took in engineering solutions to enhance oil productivity by reducing kaolinite mobilization. Specifically the paper will focus on the experiences from Oseberg Sør (North Sea). Significant formation damage has been attributed to kaolinite mobilization in this field. This damage can occur at any stage within the well lifetime from initial drilling and through the production lifecycle. SPE 107758 provided details of a unique chemical that can be incorporated into scale inhibitor squeeze treatments to reduce kaolinite mobilization while a well is in production. This paper will focus on the development of smart mud filtrate technology that incorporates kaolinite fixation agents that minimize clay mobilization within the near wellbore during drilling.
Do Viscoelastic-Surfactant Diverting Fluids for Acid Treatments Need Internal Breakers?
Authors: Huang Tianping , Crews James B.
Published: February 2008

Matrix acidizing and acid fracturing treatments have been regularly applied for enhancement of oil and gas production. The success of the acid treatments requires uniform distribution of acid fluids across long treatment intervals or areas especially for vertical, horizontal, extended reach and multilateral wells with open hole completions. The unique properties of viscoelastic surfactant (VES) fluids provide good acid diversion fluids for blocking acid fluid flow into higher permeability sections in order to force the stimulation fluid into the lower permeability sections.

Recent SPE publications have shown that VES fluids used for acid diversion fluids have caused formation damage for matrix acidizing and acid fracturing, requiring a longer flow back periods, particularly for low permeability and depleted gas formations. Internal breaker technologies for VES fluids have been developed for hydraulic fracturing and frac-packing treatments. The internal breakers give a controllable break and go wherever the VES fluid goes, breaking the VES fluid into easily producible fluid.

This paper will introduce a VES organic acid fluid with internal breakers for treating carbonate reservoirs. The VES organic acid system is unique and will not generate noticeable viscosity until the acid starts to spend. The VES within the acid fluid reaches it highest viscosity as the acid completely spends and diverts fresh acid to new locations. After acid treatments, the internal breaker becomes activated to break the VES micelles, and the fluid loses its viscosity and flows back during production, minimizing any potential damage.

The paper will discuss lab results which demonstrate that the VES product generates very high viscosity at low shear rates in the spent acid fluid, and VES fluid will not broken only by contacting hydrocarbons. Further demonstrated is how internal breakers are available that reduce the viscosity of the spent acid diverter fluid over a controllable period of time. Carbonate wormholing core flow tests show non-broken VES fluids in wormholes need much higher pressure drop than than broken VES fluids for mineral oil cleanup.
Dynamic Underbalanced Perforating Application Increases Productivity in the Mature High-Permeability Gas Reservoirs of Santa Ana Field, Venezuela
Authors: Medina M. , Morantes G. , Morales J. , Guevara W. , Romero J. , Gonzalez Y.
Published: February 2008

Located in Eastern Venezuela the Santa Ana Field is part of the most important gas province of Venezuela: Anaco District. Its main productive zones are the Merecure and San Juan formations, which are sandstones characterized by their high permeabilities (100 - 500 md) and low pressures (1200 - 2200 psi).

The wells in Anaco District are normally perforated using conventional static underbalanced techniques. The productivity of these wells was evaluated using nodal analysis techniques coupled with perforating performance simulations. The quality and amount of data was recognized to be limited. However, a qualitative diagnosis of these results indicated that the static underbalanced condition and the shaped charges used were not enough to effectively clean the perforation tunnel and surpass the near wellbore damaged zone.

Dynamic underbalanced perforating coupled with high performance charges was selected as the technology that would improve productivity in the challenging wells of Santa Ana. This technology has been applied in similar scenarios across the industry in recent years, although no documentation was found on its use in such low pressure environments.

This paper describes how dynamic underbalanced perforating was deployed successfully, while pushing the limits of its application envelope. To obtain a dynamic underbalanced condition in such a low pressure environment, the shot density had to be reduced to 2.5 spf, raising concerns about its effect on well productivity. Two wells were selected for this field trial. They were perforated using a TCP/DST string, which allowed the well to be tested immediately after perforating. Details of the diagnosis, planning, execution and evaluation phases of this project are described.

The resulting gas production and zero perforation skin represented more than a two-fold productivity increase compared with the target reservoir average well production. These results demonstrate the effectiveness of the technique under borderline conditions, and promote its application in similar scenarios worldwide.

This project shows the importance of production and perforating diagnosis, leveraging technology application and pushing the limit of dynamic underbalanced perforating in order to increase productivity in mature/low pressure assets.
Sand Control Completions for the Development of Albacora Leste Field
Authors: Pedroso C. A. , Sanches E. M. , Oliveira N. S. , Mickelburgh I. J. , Guimaraes C. R
Published: February 2008

The Campos Basin in Brazil is one of the most challenging areas for completions in the world due to the lack of formation consolidation, the large percentage of fines present in the reservoir, the heavy oil, the low frac gradients, the low net-to-gross ratio, the low bottomhole temperatures and the requirement for pressure maintenance.

The development of the Albacora Leste Field in the ultra deep water Campos Basin was a key component of Brazil's drive to achieve petroleum self sufficiency by 2006.

Because of the challenges presented by the heavy oil and the large geographical extension of the reservoir, the decision was made to develop the field with horizontal openhole gravel packs for both producers and injectors. Fifteen production wells and eleven injector wells were drilled and completed in the field.

As a result of the perceived technical complexity of the development, and requirement to maximize completion efficiency, the operator chose to maximize the integration of the services by bundling their acquisition from a single integrated services supplier, rather than contracting the required well construction services in a discrete manner, as had been traditionally done in the Campos Basin.

Horizontal openhole gravel packs, as planned for the development of Albacora Leste, were already an established and successful completion technique in the Campos Basin. However, the Albacora Leste wells were amongst the longest attempted in the basin, and due to the combination of the ultra deep water and limited sediment thickness, had significantly lower frac gradients than previously experienced.

The challenges of minimizing placement pressures, accurate modeling of gravel placement, rat hole mitigation, and injection well clean-up all had to be addressed. The solutions developed to meet these multiple challenges will be presented in this paper.
Development of Reactive Coatings to Protect Sand-Control Screens
Authors: Constien Vernon , Coffey Dewayne
Published: February 2008

Sand control screens are susceptible to plugging during installation in the wellbore and during production. One common source of plugging material is drilling fluid components left in the wellbore as whole mud or filtercake. In the past, screens have been coated to prevent plugging during installation. These early coatings were designed to dissolve at elevated temperature or be removed by acid treatment. While this approach protected the screens from plugging during installation, it did not address the potential for plugging by mud solids during production. To minimize the plugging due to mud solids, reactive coatings are being developed to protect sand control screens from plugging during installation and during production. New reactive coating formulations are designed with mechanical and chemical properties that will remain intact until the screens are placed in the wellbore. Once in place, the coatings begin to dissolve and release reactive materials such as acids, enzymes, or chelants into the near wellbore area to react with and degrade the drilling fluid components which could plug the screen.
Collapse Analysis of Screens Used in Horizontal Open Hole Gravel Pack Completion
Authors: Santos Anderson Rapello dos , Silva Patrick Perez da , Vargas Eurípedes do Amaral , Braga Arthur Martins Barbosa
Published: February 2008

Global increase in energy demand and the lack of opportunities onshore or in shallow waters are driving production of hydrocarbons towards deep and ultra deep-water basins, where reservoirs are usually formed by weak and unconsolidated sandstones that require sand control methods to prevent damage in surface and subsurface equipments.

Guidelines to select sand control systems are primarily based on sand exclusion, seeking to optimize balance between oil rate and fines production. Another aspect, often overlooked, is collapse strength of the system formed by the sand control equipment and the formation itself, subjected to mechanical loadings that change during life of the well.

This contribution presents a method to evaluate collapse strength of sand control systems taking into account mechanical interaction between the formation and sand control screens. Elastoplastic models are used to represent granular materials.

The most usual sand control system was studied: gravel pack with premium screens. A model to describe contact between granular materials (gravel and formation) and soil-pipe interaction is proposed. Results demonstrate that perforated base pipes used in premium screens may be oversized for applications under regular operating conditions.
Weighted Frac Fluids for Lower-Surface Treating Pressures
Authors: Simms Lloyd , Clarkson Brad , Navaira Gilbert
Published: February 2008

With Gulf of Mexico (GOM) hydrocarbon discoveries reaching record depths and very high bottomhole pressures, the need for proven, weighted fracturing stimulation fluids has become urgent. As previous studies have shown, frac packs have a significant impact in maintaining well productivity in the later production life stages of unconsolidated reservoirs. Thus, sustaining the ability to pump frac packs in these challenging environments is a priority.

With conventional frac pack fluids, these greater depths and higher bottomhole pressures often would result in the need for surface treating pressures that exceed the limits of current surface equipment and tubulars. Surface treating pressure can be calculated using the equation:

(1) P s = BHTP + P fric − P hyd

Ps = surface pressure

BHTP = bottomhole treating pressure

Pfrict = friction pressure

Phyd = hydrostatic pressure

The equation shows that an increase in hydrostatic pressure results in a reduction in surface pressure. This is true as long as any corresponding increases in BHTP and friction pressure remain below the hydrostatic increase. If substantial reductions in surface pressure can be achieved, then frac pack treatments remain a safe and viable option in deepwater and ultra-deepwater environments.

As of October 2007, sixteen total jobs have been pumped with a weighted frac pack fluid. Of these jobs, eleven treatments have been pumped by Chevron in the deepwater GOM. This paper presents data from these treatments where substantial reductions in surface treating pressures were observed. Also shown is the accuracy to which surface treating pressures with the weighted frac-pack fluid can be predicted.
When Will Low Sulphate Seawater No Longer Be Required on the Tiffany Field?
Authors: Al-Riyami Murshid , Mackay Eric , Deliu Gabriel , Jordan Myles , McElhiney John
Published: February 2008

Injection of sulphate rich seawater into reservoirs with formation brines rich in calcium, barium or strontium may result in the precipitation of sulphate scales. One technique for managing mineral scales in fields where scale inhibitor squeeze treatments may prove very difficult or ineffective is injection of low sulphate seawater. The CNR operated Tiffany field in the North Sea is one of the oilfields that has been swept with low sulphate seawater for the longest period (> 10 years) and from the start of water injection, and consequently yields useful information on brine mixing and brine-rock interactions during low sulphate seawater sweep. This paper presents the evolution of individual well brine chemistry data, backed up by reservoir simulation and reactive transport flow modelling, which demonstrates the effect that low sulphate seawater injection has had on the produced brine chemistry. The main impact is that scale inhibitor squeezes have only been required for carbonate scales.

The modelling has been extended to predict future individual well brine compositions to identify potential barium and sulphate concentrations to end of field life, and hence identify any remaining potential barium sulphate scaling risk. However, the predictive modelling has also been used to study the sensitivity to timing of a switch from desulphated to full sulphate seawater injection towards the end of field life, to address the question of when will low sulphate seawater no longer be required on the Tiffany field? This study has significant implications for other basins around the world where desulphation projects are about to commence (Brazil and Angola).
Inhibition Mechanisms for Sulphide Scales
Authors: Okocha C. , Sorbie K. S. , Boak L. S.
Published: February 2008

Sulphide scales have over recent years become increasingly common in many oil and gas producing regions. The main sulphide scales are iron, zinc and lead, with the latter two often occurring together. This paper presents experimental results from a series of static iron sulphide (FeS) inhibition efficiency tests using 2 scale inhibitors (SI), a phosphonate and a polymer. The paper also highlights the methodology which has been developed for assessing iron sulphide scale inhibition. The objective of this preliminary iron sulphide inhibition efficiency study was (a) to establish which of the conventional SI tested inhibit FeS and under which test conditions; (b) to determine the mechanisms through which SIs inhibit FeS; and (c) to determine if it is possible to determine a "minimum inhibitor concentration" (MIC) with this methodology. This preliminary study shows that: (i) The conventional SIs tested in this study do inhibit FeS scale formation; (ii) A clarification phenomenon was observed after sulphide formation using conventional phosphonate which has not been observed/reported previously. This involves the formation of black FeS and the clarification that follows after 24hrs, which indicates subsequent "inhibition", although probably by direct chelation rather than by threshold (sub-stoichiometric) inhibition; (iii) It is possible to obtain an "MIC" from the static bottle test.
Modeling of Three-Phase Flow in the Annuli During Directional UBD Operations
Authors: Mousavi Hasan , Mostafavi Vahidreza , Nazari Tahmineh , Hareland Geir , Shirkavand Farid
Published: February 2008

Underbalanced drilling (UBD) has several advantages compared to conventional drilling. These advantages include the elimination of formation damage, higher penetration rate, reducing circulation loss and the possibility of actually producing hydrocarbons during the drilling process. UBD technology and applications have recently been applied while drilling challenging wells in Iranian fields.

It is generally accepted that the success of underbalanced drilling is dependant on maintaining the wellbore pressure in an operational window determined by the formation pressure, wellbore stability, and the capacity of the surface equipment.

There are several models which can predict the wellbore pressure. Traditional models are mostly empirical and lead to acceptable results for specific conditions but fail for other conditions.

In the last decade of the last century, some mechanistic models have been developed which result in an acceptable range of outcomes for a wide variety of reservoirs.

On the other hand due to the dynamic nature of the process, some researchers have recently focused on development of dynamic models.

This paper presents an improved, comprehensive, mechanistic model for pressure prediction through a well during UBD operations. The comprehensive model consists of a set of correlations for predicting flow pattern and estimating the pressure in addition to two-phase flow parameters in bubble, dispersed bubble, and slug flow. On the other hand the most recently developed empirical correlations have been applied to determine PVT properties. The accuracy of these correlations has been tested in more than 20 oil wells in Iran. Naseri et al. and Almarhoun correlations was applied to determine the live and dead oil viscosities. Naseri et al. model which was originally developed for Iranian reservoirs was used in our model and the results are promising.
Preburn Characteristics and Woodpecker Use of Burned Coniferous Forests
Authors: VIERLING KERRI T. , LENTILE LEIGH B. , NIELSEN‐PINCUS NICOLE
Published: February 2008

ABSTRACT  Large wildfires are common in many western coniferous forests, and these fires can affect woodpecker reproduction and habitat use. Our objectives were to examine nesting densities, reproductive parameters, and species‐specific habitat selection of woodpeckers in a recently burned region of the Black Hills in South Dakota, USA, between 2001 and 2004. Postfire nesting densities were greatest in areas dominated by high prefire canopy cover, and reproductive success averaged >70%. For some species of woodpeckers, factors such as diameter at breast height, burn severity, and distance to unburned patches were important for nest‐site selection. Our data indicated that nesting densities of many woodpeckers in the Black Hills were lower than what has been recorded elsewhere following recent, large wildfires in ponderosa pine (Pinus ponderosa) forests. Management activities that simulate mixed‐severity fire effects and retain higher numbers of large snags are likely to benefit cavity nesters in this region.
Effects of US 1 Project on Florida Key Deer Mortality
Authors: PARKER ISRAEL D. , BRADEN ANTHONY W. , LOPEZ ROEL R. , SILVY NOVA J. , DAVIS DONALD S. , OWEN CATHERINE B.
Published: February 2008

ABSTRACT  Approximately 26% of annual mortality for the endangered Florida Key deer (Odocoileus virginianus clavium) occurs as deer‐vehicle collisions (DVCs) on the 5.6‐km section of United States Highway 1 (US 1) on Big Pine Key (BPK), but extensive urban development adjacent to sections of US 1 complicates efforts to reduce DVCs. Our objective was to evaluate the effectiveness of the US 1 Project (continuous 2.6‐km system of 2.4‐m fencing, 2 underpasses, and 4 experimental deer guards constructed on US 1 on BPK) in reducing DVCs along US 1. Deer used the underpasses all 3 postproject years (2003–2005); however, we observed higher underpass use in 2004 and 2005 compared to 2003. Exclusion fencing reduced deer intrusions onto the fenced section of US 1 during the 3‐year period (2003, n = 7 deer; 2004, n = 4; 2005, n = 12). With a reduction of deer intrusions onto this section of US 1, DVCs decreased in the fenced area by 73–100%; however, US 1 DVCs within the unfenced sections of US 1 also increased (40%) as expected. In controlling for effects of increasing deer density and traffic volume, study results suggest that highway improvements have decreased the net risk of DVCs along US 1, which indicates that use of deer fencing, deer guards, and underpasses is applicable in other urban communities experiencing unacceptable levels of DVCs.
African Grazing Lawns—How Fire, Rainfall, and Grazer Numbers Interact to Affect Grass Community States
Authors: ARCHIBALD S.
Published: February 2008

ABSTRACT  Grazing lawns are recognized as important components of many savanna ecosystems, but there is no clarity on their origin or their stability in space and time. Some researchers believe soil nutrients control grazing lawn distributions. Others believe feedbacks created by herding mammals grazing in patches can promote the spread of grazing lawns without soil nutrient differences. This in turn is affected by rainfall and fire. We presented a simulation model that tests the conditions required for the initiation and spread of grazing lawns. Lawns were shown to develop in a homogeneous soil substrate, but only during periods of low rainfall, high grazer densities, and infrequent fires. Including heterogeneity in the model did not increase grazing lawn area but did reduce the effectiveness of frequent fires in preventing their establishment. We compared these results with conditions in a typical savanna park in Southern Africa. Running the model under current fire, grazing, and rainfall conditions reproduced the current grazing lawn proportions in the park. Using lower fire frequencies and higher grazer densities—such as were experienced in the park in the last 100 years—could more than double the proportion of grazing lawns in the park.
Reducing Tick Burdens on Chicks by Treating Breeding Female Grouse With Permethrin
Authors: MOUGEOT FRANCOIS , MOSELEY MARK , LECKIE FIONA , MARTINEZ‐PADILLA JESUS , MILLER ALLEN , POUNDS MAT , IRVINE R. JUSTIN
Published: February 2008

ABSTRACT  Ticks are important arthropod vectors of diseases of human, livestock, and wildlife hosts. In the United Kingdom, the sheep tick (Ixodes ricinus) is increasingly recognized as a main limiting factor of red grouse (Lagopus lagopus) populations, a game bird of high economic value. We evaluated the effectiveness of a new practical technique that could help managers reduce negative impacts of ticks on young grouse. In a replicated field experiment, we treated breeding females with leg bands impregnated with permethrin, a slow‐releasing potent acaracide. We found that treatment reduced tick burdens on young chicks. Because this treatment is easily applied, it offers a new practical management tool to tackle problems caused by ticks in game bird populations.
Effects of Impact Perception on Acceptance Capacity for White‐Tailed Deer
Authors: LISCHKA STACY A. , RILEY SHAWN J. , RUDOLPH BRENT A.
Published: February 2008

ABSTRACT  Wildlife professionals require conceptually sound methods to integrate biological and social insights for management of wildlife. The concept of acceptance capacity has been suggested to stimulate integration, although methods to link measures of acceptance capacity with measures of wildlife populations are not fully developed. To clarify relationships between acceptance capacity, wildlife populations, and human values, we explored effects of stakeholder characteristics and impact perception (the recognized, important effects arising from interactions with wildlife) on acceptance capacity. We used a mail‐back questionnaire (n = 2,190 responses) to rural residents of southern Michigan 1) to examine whether 3 commonly identified stakeholder groups (hunters, farmers, and nonhunting, nonfarming rural residents) that share a common landscape also perceive similar suites of impacts and hold comparable acceptance capacities for white‐tailed deer, and 2) to develop an explanatory model of acceptance capacity for deer. Comparisons among stakeholder groups revealed differences in perception of impacts resulting from interactions with deer; however, participation in hunting and farming were poor predictors of acceptance capacity for deer. Model selection criteria indicate that total effect of impacts perceived explains a majority of variation in acceptance capacity. We conclude that impact perception is a meaningful concept for integration of human values into management of wildlife populations because impacts relate to effects of current wildlife populations and can lead to management actions that address needs and interests of multiple stakeholder groups in changing landscapes.
Genetic Structure and Evidence of a Local Bottleneck in Moose in Sweden
Authors: CHARLIER JOHAN , LAIKRE LINDA , RYMAN NILS
Published: February 2008

ABSTRACT  The moose (Alces alces) is the most intensely managed game species in Sweden. Despite the biological and socioeconomical importance of moose, little is known of its population genetic structure. We analyzed 132 individuals from 4 geographically separate regions in Sweden for genetic variability at 6 microsatellite loci. We found evidence of strong substructuring and restricted levels of gene flow in this potentially mobile mammal. FST values were around 10%, and assignment tests indicated 3 genetically distinct populations over the study area. Spatial autocorrelation analysis provided a genetic patch size of approximately 420 km, implying that moose less than this distance apart are genetically more similar than 2 random individuals. Allele and genotype frequency distributions suggested a recent bottleneck in southern Sweden. Results indicate that moose may be more genetically divergent than currently anticipated, and therefore, the strong hunting pressure that is maintained over all of Sweden may have considerable local effects on genetic diversity. Sustainable moose hunting requires identification of spatial genetic structure to ensure that separate, genetically distinct subpopulations are not overharvested.
Biological and Statistical Errors Make Inferences Circumspect: Response to Bender and Weisenberger
Authors: ROMINGER ERIC M. , GOLDSTEIN ELISE J. , EVANS MARC A.
Published: February 2008

ABSTRACT  Bender and Weisenberger (2005) reported that desert bighorn sheep (Ovis canadensis) on San Andres National Wildlife Refuge (SANWR), New Mexico, USA, were primarily limited by rainfall. However, they failed to mention, or were unaware, that persistent long‐term predator control was used to enhance population growth at SANWR. Additionally, lamb:female ratios were collected throughout the year, rather than dates typically associated with assessing recruitment, and therefore influence of precipitation on lamb recruitment was unknown. Finally, model predictions forwarded by Bender and Weisenberger (2005), that carrying capacity of SANWR is zero when annual rainfall is <28.2 cm, were not supported by data, nor were their model results properly interpreted. The coefficient of determination value of 88.9% for the relationship between population size and current year's precipitation was primarily a function of serial correlation between successive years in population data, with current year's precipitation accounting for only 3.8% of this value. This suggests that precipitation was a weak predictor of population increase. These errors in concert make biological inferences reported in Bender and Weisenberger (2005) of limited value.
Influence of Vegetation on Bat Use of Riparian Areas at Multiple Spatial Scales
Authors: OBER HOLLY K. , HAYES JOHN P.
Published: February 2008

ABSTRACT  Research on habitat use by bats typically occurs at a single fine spatial scale, despite recent work demonstrating the importance of considering multiple spatial scales when investigating vertebrate habitat selection. We assessed bat use of 118 stream reaches located throughout the Oregon Coast Range, USA, and measured vegetation characteristics at 3 spatial scales surrounding each of these locations. We used an information‐theoretic approach to determine vegetation characteristics most closely related to bat activity and a multilevel modeling approach to evaluate variation in bat activity at different spatial scales. Characteristics of vegetation at the finest spatial scale explained more variation in bat activity than did characteristics of vegetation at broader spatial scales, suggesting that fine‐scale anthropogenic or natural disturbance events that alter cover of shrubs or trees in riparian areas are likely to influence bat habitat use. The influence of vegetation on activity varied by species of bat and appeared to operate more strongly through constraints imposed by vegetation architecture than through influences on abundance of insect prey. This diversity of responses to vegetation characteristics among bat species suggests that the best strategy for biodiversity conservation over broad spatial scales is maintenance or creation of a diversity of riparian vegetation conditions. We recommend that land managers planning to manipulate riparian vegetation strive to create diversity in shrub coverage, canopy coverage, and open space above the stream channel to promote foraging habitat for all species.
Natal Den Selection by Florida Panthers
Authors: BENSON JOHN F. , LOTZ MARK A. , JANSEN DEBORAH
Published: February 2008

ABSTRACT  Information regarding habitat types selected by federally endangered Florida panthers (Puma concolor coryi) at natal den sites is needed because habitats used for parturition and kitten rearing potentially influence fitness of individuals and viability of the population. We located 51 natal den sites of 30 female panthers and performed a Euclidean distance analysis to determine which habitat types were selected and avoided at dens in south Florida, USA. Panther dens were closer to upland hardwoods, pinelands, and mixed wet forests (P ≤ 0.003) and farther from freshwater marsh‐wet prairie (P = 0.009). We recommend that habitat protection efforts prioritize blocks of land that have abundant patches of upland hardwood, pinelands, and mixed wet forests to maintain preferred panther denning habitat.
A Rational Expectations Theory of Kinks in Financial Reporting
Authors: Guttman Ilan , Kadan Ohad , Kandel Eugene
Published: February 2008

We present a rational model of earnings management. An informed manager, whose compensation is linked to the stock price, trades off the benefit of boosting the stock price by inflating the reported earnings against the costs of such manipulation. The investors rationally interpret his actions and adjust the price accordingly. When the distribution of true earnings and the compensation scheme are smooth, the conventional equilibrium in this signaling framework is also smooth and fully revealing. In this paper, we show that in the same “smooth” environment there exist equilibria in which kinks and discontinuities emerge endogenously in the distribution of reported earnings. The manager optimally chooses a partially pooling strategy, introducing endogenous noise into his report. The resulting vagueness enables the manager to reduce the average manipulation costs. The equilibrium has perfect revelation of earnings in the right and left tails of the distribution, while for intermediate earnings realizations, we get one or more pools that manifest themselves as discontinuities in the distribution of reported earnings. We study the properties of these partially pooling equilibria and suggest applications to financial reporting.
Perspectives on Evidence-Based Research in Education—What Works? Issues in Synthesizing Educational Program Evaluations
Authors: Slavin Robert E.
Published: February 2008

Syntheses of research on educational programs have taken on increasing policy importance. Procedures for performing such syntheses must therefore produce reliable, unbiased, and meaningful information on the strength of evidence behind each program. Because evaluations of any given program are few in number, syntheses of program evaluations must focus on minimizing bias in reviews of each study. This article discusses key issues in the conduct of program evaluation syntheses: requirements for research design, sample size, adjustments for pretest differences, duration, and use of unbiased outcome measures. It also discusses the need to balance factors such as research designs, effect sizes, and numbers of studies in rating the overall strength of evidence supporting each program.
Comments on Slavin: Synthesizing Causal Inferences
Authors: Briggs Derek C.
Published: February 2008

When causal inferences are to be synthesized across multiple studies, efforts to establish the magnitude of a causal effect should be balanced by an effort to evaluate the generalizability of the effect. The evaluation of generalizability depends on two factors that are given little attention in current syntheses: construct validity and external validity. The author concludes with six concrete suggestions for ways that future syntheses could be improved to make them more relevant for educational policy makers.
Comments on Slavin: Becoming Critical Readers: Issues in Transparency, Representation, and Warranting of Claims
Authors: Green Judith L. , Skukauskaitė Audra
Published: February 2008

This response to Slavin’s article (2008) explores the issues of transparency, representation, and warranting of claims in Slavin’s descriptions of the work of others and his suggestions for program evaluation syntheses. Through contrastive analyses between Slavin’s representations of the program evaluation synthesis efforts of five organizations and their own representations of their synthesis work, the authors uncover the ways in which the gaps in Slavin’s text become consequential for readers, limiting readers’ opportunities for developing understandings of synthesis efforts. Through contrastive analyses, the authors foreground the need for transparency in reporting, raise questions about the use of narrowly focused reviews, and demonstrate how a contrastive analysis of texts may constitute a productive approach to critical reading and an opportunity for learning.
Identification of Causal Parameters in Randomized Studies With Mediating Variables
Authors: Sobel Michael E.
Published: February 2008

Treatments in randomized studies are often targeted to key mediating variables. Researchers want to know if the treatment is effective and how the mediators affect the outcome. The data are often analyzed using structural equation models (SEMs), and model coefficients are interpreted as effects. However, only assignment to treatment groups is randomized, so mediators are self-selected treatments. Thus, the so-called direct effects of mediators on later outcomes do not usually warrant a causal interpretation. Holland (1988) studied the case of a single continuous mediator, criticizing the use of SEMs. He uses treatment assignment as an instrument for the effect of the mediator on the outcome. However, the assumptions he made to justify this approach are overly strong and substantively implausible. This article (a) makes explicit the assumptions needed to justify equating the parameters of SEMs with the effects of mediators, (b) provides weaker and more plausible conditions under which the instrumental variable estimand may be interpreted as an effect, and (c) extends the analysis to include the case of noncompliance.
Austria’s Path Toward Nationwide Electronic Health Records
Authors: Duftschmid G. , Gerhold L. , Gall W. , Gambal J. , Dorda W.
Published: February 2008

Objectives:
This article discusses current planning activities in Austria after legislation has been passed to introduce the electronic health record (EHR).

Methods:
After describing similar activities in several other countries, the authors explore the current situation of healthcare telematics and imminent steps toward the implementation of a lifelong EHR.

Results:
Substantial efforts have been made to coordinate healthcare telematics in Austria since the mid-1990s. One result of these efforts was the definition of a framework for electronic data exchange. A number of standardization projects were also implemented. Major steps have been taken as part of an ongoing healthcare reform to promote the use of healthcare telematics. One important example is a national initiative whose objective is to implement the EHR. This initiative is extensively discussed along with other national activities related to healthcare telematics.

Conclusion:
This EHR initiative has prepared the ground for extensive planning that is currently under way to implement a lifelong EHR in Austria on a national level. Introducing the EHR will have a strong impact on Austrian healthcare and should be performed in concert with international activities. The authors offer a number of practical recommendations for the implementation of an EHR on a national level.
Development of a Telediagnosis Endoscopy System over Secure Internet
Authors: Sakamoto N. , Watanabe M. , Mizushima H. , Tanaka H. , Ohashi K.
Published: February 2008

Objectives:
We developed a new telediagnosis system to securely transmit high-quality endoscopic moving images over the Internet in real time. This system would enable collaboration between physicians seeking advice from endoscopists separated by long distances, to facilitate diagnosis.

Methods:
We adapted a new type of digital video streaming system (DVTS) to our teleendoscopic diagnosis system. To investigate its feasibility, we conducted a two-step experiment. A basic experiment was first conducted to transmit endoscopic video images between hospitals using a plain DVTS. After investigating the practical usability, we incorporated a secure and reliable communication function into the system, by equipping DVTS with “TCP2”, a new security technology that establishes secure communication in the transport layer. The second experiment involved international transmission of teleendoscopic image between Hawaii and Japan using the improved system.

Results:
In both the experiments, no serious transmission delay was observed to disturb physicians’ communications and, after subjective evaluation by endoscopists, the diagnostic qualities of the images were found to be adequate. Moreover, the second experiment showed that “TCP2-equipped DVTS” successfully executed high-quality secure image transmission over a long distance network.

Conclusions:
We conclude that DVTS technology would be promising for teleendoscopic diagnosis. It was also shown that a high quality, secure teleendoscopic diagnosis system can be developed by equipping DVTS with TCP2.
Content of Patient Electronic Messages to Physicians in a Large Integrated System
Authors: Liu Vincent X , Kaercher Pamela , Manickam Jennifer , Smallberg Eric , Bhutani Kanishka , Mancha Michelle , Lee Kristine
Published: April 2024

This quality improvement study describes the content of electronic health record messages from patients to physicians in a large integrated health care system using natural language processing algorithms.