bluuebunny/crossref_metadata_2025 huggingface dataset:
A Genetical Genomics Approach to Genome Scans Increases Power for QTL Mapping
Authors: Sun Guoying , Schliekelman Paul
Published: January 2011

We describe a method for integrating gene expression information into genome scans and show that this can substantially increase the statistical power of QTL mapping. The method has three stages. First, standard clustering methods identify small (size 5–20) groups of genes with similar expression patterns. Second, each gene group is tested for a causative genetic locus shared with the clinical trait of interest. This is done using an EM algorithm approach that treats genotype at the putative causative locus as an unobserved variable and combines expression information from all of the genes in the group to infer genotype information at the locus. Finally, expression QTL (eQTL) are mapped for each gene group that shares a causative locus with the clinical trait. Such eQTL are candidates for the causative locus. Simulation results show that this method has far superior power to standard QTL mapping techniques in many circumstances. We applied this method to existing data on mouse obesity. Our method identified 27 putative body weight QTL, whereas standard QTL mapping produced only one. Furthermore, most gene groups with body weight QTL included cis genes, so candidate genes could be immediately identified. Eleven body weight QTL produced 16 candidate genes that have been previously associated with body weight or body weight-related traits, thus validating our method. In addition, 15 of the 16 other loci produced 32 candidate genes that have not been associated with body weight. Thus, this method shows great promise for finding new causative loci for complex traits.
The Activator/Dissociation Transposable Elements Comprise a Two-Component Gene Regulatory Switch That Controls Endogenous Gene Expression in Maize
Authors: Bai Ling , Brutnell Thomas P
Published: January 2011

The maize Activator/Dissociation (Ac/Ds) elements are able to replicate and transpose throughout the maize genome. Both elements preferentially insert into gene-rich regions altering the maize genome by creating unstable insertion alleles, stable derivative or excision alleles, or by altering the spatial or temporal regulation of gene expression. Here, we characterize an Ac insertion in the 5′-UTR of the Pink Scutellum1 (Ps1) gene and five Ds derivatives generated through abortive transposition events. Characterization of Ps1 transcription initiation sites in this allelic series revealed several that began within the terminus of the Ac and Ds elements. Transcripts originating within Ds or Ac accumulated to lower levels than the wild-type Ps1 allele, but were often sufficient to rescue the seedling lethal phenotype associated with severe loss-of-function alleles. Transcription initiation sites were similar in Ac and Ds derivatives, suggesting that Ac transposase does not influence transcript initiation site selection. However, we show that Ac transposase can negatively regulate Ps1 transcript accumulation in a subset of Ds-insertion alleles resulting in a severe mutant phenotype. The role of maize transposons in gene evolution is discussed.
The LIN-15A and LIN-56 Transcriptional Regulators Interact to Negatively Regulate EGF/Ras Signaling inCaenorhabditis elegansVulval Cell-Fate Determination
Authors: Davison Ewa M , Saffer Adam M , Huang Linda S , DeModena John , Sternberg Paul W , Horvitz H Robert
Published: January 2011

The restricted expression of epidermal growth factor (EGF) family ligands is important for proper development and for preventing cancerous growth in mammals. In Caenorhabditis elegans, the class A and B synthetic multivulva (synMuv) genes redundantly repress expression of lin-3 EGF to negatively regulate Ras-mediated vulval development. The class B synMuv genes encode proteins homologous to components of the NuRD and Myb-MuvB/dREAM transcriptional repressor complexes, indicating that they likely silence lin-3 EGF through chromatin remodeling. The two class A synMuv genes cloned thus far, lin-8 and lin-15A, both encode novel proteins. The LIN-8 protein is nuclear. We have characterized the class A synMuv gene lin-56 and found it to encode a novel protein that shares a THAP-like C2CH motif with LIN-15A. Both the LIN-56 and LIN-15A proteins localize to nuclei. Wild-type levels of LIN-56 require LIN-15A, and wild-type levels and/or localization of LIN-15A requires LIN-56. Furthermore, LIN-56 and LIN-15A interact in the yeast two-hybrid system. We propose that LIN-56 and LIN-15A associate in a nuclear complex that inhibits vulval specification by repressing lin-3 EGF expression.
Rapid Identification of a Disease Allele in Mouse Through Whole Genome Sequencing and Bulk Segregation Analysis
Authors: Arnold Carrie N , Xia Yu , Lin Pei , Ross Charles , Schwander Martin , Smart Nora G , Müller Ulrich , Beutler Bruce
Published: January 2011

In a pedigree of C57BL/6J mice homozygous for germline mutations induced by the mutagen N-ethyl-N-nitrosourea (ENU), numerous animals died under specific pathogen-free (SPF) conditions between 6 and 7 months of age. Death was caused by nephritic syndrome, which progressed to renal failure associated with focal segmental glomerulosclerosis. To identify the mutation responsible for renal disease, we sequenced genomic DNA from an affected animal using the Applied Biosystems SOLiD sequencing platform. Approximately 74% of the nucleotides comprising coding sequences and splice junctions in the mouse genome were covered at least three times. Within this portion of the genome, 64 discrepancies were flagged as potential homozygous mutations and 82 were flagged as potential heterozygous mutations. A total of 10 of these calls, all homozygous, were validated by capillary sequencing. One of the validated mutations disrupted splicing of the Col4a4 transcript. Genetic mapping by bulk segregation analysis excluded all mutations but this one as the cause of renal disease in Aoba mice. Col4a4 has not been targeted in the mouse, and this strain, named Aoba, represents the first functionally null allele in this species. Our study demonstrates the speed and utility of whole genome sequencing coupled with low resolution meiotic mapping as a means of identifying causative mutations induced by ENU.
Analysis of a Model for Anomalous-Diffusion Behavior of CO2 in the Macromolecular-Network Structure of Coal
Authors: Mazumder Saikat , Vermolen Fred , Bruining Johannes
Published: January 2011

This paper gives an analysis of the Thomas and Windle model (Thomas and Windle 1982) to determine its usefulness for describing anomalous diffusion of CO2 in coal and its relation to matrix swelling. In addition, a finite-element description for this model is derived. For reasons of easy reference, a shortened derivation of the Thomas and Windle model is presented, which was originally derived to describe diffusion in polymers. The derivation includes the surface saturation effects proposed by Hui et al. (1987a, 1987b). Because the cumulative sorption showed tα behavior with α > 0.5, the behavior was described as enhanced diffusion or even superdiffusion. Analysis of the model equation shows no evidence for superdiffusion even if non-Fickian behavior is observed [i.e., there is (1) an initial phase in which the coal surface gets saturated with a slope > 0.5 in a log-log plot of cumulative sorption vs. time, (2) an intermediate phase that shows the typical square-root-of-time behavior of an ordinary diffusion process, and (3) a final phase with a slope < 0.5 toward equilibrium]. The cumulative mass is for all times less than what would have been obtained for pure diffusion in a particle characterized by a rubber diffusion coefficient. The slow saturation at the surface masks a process where fast stress-induced diffusion dominates, which indeed can be faster than Fickian. The cumulative sorption rates give behavior similar to the Rückenstein model (Rückenstein et al. 1971), but the advantage of the Thomas and Windle model is that it can also calculate the resulting coal-swelling effects.
Parallel Numerical Reservoir Simulations of Nonisothermal Compositional Flow and Chemistry
Authors: Delshad M.. , Thomas S.G.. G. , Wheeler M.F.. F.
Published: January 2011

This paper describes an efficient numerical scheme for nonisothermal compositional flow coupled to chemistry. An iterative implicit-pressure/explicit-composition (IMPEC) method is applied to solve the flow problem using a volume-balance-convergence criterion. A backward-Euler mixed finite-element method (FEM) with lowest-order RT0 elements is applied to solve the pressure equation, and a component local mass-preserving explicit scheme is used to update concentrations. Chemical reactions are solved using explicit Runge-Kutta (RK) ordinary-differential-equation (ODE) integration schemes. A higher-order Godunov method and a backward-Euler mixed FEM are applied for thermal advection and conduction, respectively, in a time-split scheme.

One of the major applications of the method is in the modeling of field-scale carbon dioxide (CO2) sequestration as an enhanced-oil-recovery (EOR) process or for containment in deep saline aquifers where chemical reactions and temperature variations may have an effect on the flow and transport of CO2. Leakage patterns when CO2 is injected near leaky abandoned wells, the displacement of methane from depleted gas reservoirs, and accurate modeling of geochemical reactions involving injected CO2 are other applications of interest.

Results of a benchmark problem in multiphase flow with several hydrocarbon components in formations with highly heterogeneous permeability on very fine grids, as well as a large-scale parallel implementation of modeling CO2 sequestration, are presented to justify the practical use of the model. A parallel efficiency of approximately 80% was observed on up to 512 cores in the benchmark study. Results from a problem simulating injection of CO2 in deep aquifers including nonisothermal and chemical effects are also presented. The results indicate a good agreement of the solutions with published data, where available.

Numerical modeling and simulation of CO2 sequestration plays a major role in future site selections and in designing storage facilities for effective CO2 containment. The main contribution of this paper lies in providing a parallel and efficient method of simulating challenging compositional flow problems, such as in the study of CO2 sequestration, as well as flow coupled to thermal and geochemical effects.
Barite Nucleation and Inhibition at 0 to 200°C With and Without Thermodynamic Hydrate Inhibitors
Authors: Fan Chunfang , Kan Amy T. , Zhang Ping , Tomson Mason B.
Published: January 2011

In this study, we modified the commonly employed dynamic-tube-blocking methodology and built an apparatus to study the nucleation kinetics of barite-scale formation at high temperatures in the presence and absence of scale inhibitors. Barite formation was detected by monitoring pressure change over a micrometer-sized in-line filter, and this has been proved to be an easy and accurate method to study mineral-scale-nucleation kinetics at high temperatures. Additionally, we investigated the nucleation kinetics of barite at 0–25°C with and without thermodynamic hydrate inhibitors. By using this modified dynamic-tube-blocking technique, we successfully measured the nucleation kinetics of barite in 1M NaCl solutions over a temperature range from 25 to 200°C and at various supersaturation conditions. We also evaluated the inhibition efficiency of barite precipitation at this high temperature range. On the basis of the experimental results, the relationship of precipitation kinetics of barite as a function of temperature and saturation index was established. The inhibition efficiency of the phosphonate inhibitor [bis-hexamethylenetriamine-penta (methylene phosphonic) acid (BHPMP)] on barite precipitation has been evaluated over the same range of conditions. The Ca2+ effect on the inhibition efficiency of BHPMP at a low temperature (4°C) and at high temperatures (175–200°C) was investigated also. Results of this study have been incorporated into the scale-prediction software ScaleSoftPitzer.
pH-Sensitive Polymers for Novel Conformance-Control and Polymer-Flood Applications
Authors: Choi Suk Kyoon , Sharma Mukul M. , Bryant Steven L. , Huh Chun
Published: January 2011

Novel conformance-control and polymer-flood applications that exploit the pH sensitivity of partially hydrolyzed polyacrylamide (HPAM) are proposed. The key feature of this process is the injection of the HPAM solution under acidic conditions. The low pH makes polymer molecules coil tightly, resulting in a very low polymer-solution viscosity. This allows the polymer solution to be injected into the reservoir at a substantially reduced injection pressure. Once injected, the acid reacts with the formation minerals to cause a spontaneous pH increase, uncoiling the polymer chains and causing a large increase in solution viscosity. Such a viscosity-control scheme can be exploited for placement of a concentrated polymer solution in high-permeability zones, where it later viscosifies to divert subsequently injected fluids (in-depth conformance control), or to reduce the high pressure drop near the wellbore during polymer injection (injectivity improvement).

Extensive laboratory experiments were systematically performed and interpreted to evaluate the novel applications of pH-sensitive HPAM. The evaluations require (a) quantification of steady-shear viscosities, (b) characterization of geochemical reactions with acids, and (c) transport evaluation of HPAM solutions in cores. Rheological measurements show that shear viscosities of HPAM solution have a pronounced, but reversible, dependence on pH. The peak pHs observed in several shut-ins guarantee that spontaneous geochemical reactions can return the polymer solution to its original high viscosity. The use of a weak acid is the key. Coreflood results show that the HPAM solution under acidic conditions can be propagated through cores with much higher mobility than at neutral pH. However, low-pH conditions increase adsorption (polymer loss) and require additional chemical cost (for acid). The optimum injection formulation (polymer concentration, injection pH) will depend on the specific reservoir mineralogy, permeability, salinity, and injection conditions.
Exponential Growth in San Juan Basin Fruitland Coalbed Permeability With Reservoir Drawdown: Model Match and New Insights
Authors: Shi J.-Q.. -Q. , Durucan S..
Published: January 2011

The exponential-growth behavior of coalbed permeability with reservoir pressure depletion has been observed previously at the Fairway wells in the San Juan basin. More recently, the exponential trend has also been confirmed for a group of 10 wells in a region northeast of Fairway. Increase in the absolute permeability of coalbeds is a result of matrix shrinkage caused by gas desorption, which becomes a dominant factor on cleat permeability over the effective-stress effect during reservoir production.

A permeability model previously developed by the authors has been revisited in an effort to match the recently published field-permeability data. The Shi and Durucan (S&D) permeability model (2004, 2005a) makes use of a stress permeability relationship reported in the literature for an idealized geometry (matchsticks), in which the permeability varies exponentially with changes in the effective horizontal stress through the use of a constant cleat (pore) compressibility parameter. In this study, a stress-dependent cleat volume compressibility defined by an initial compressibility with a negative exponential decline rate was adopted. By tuning these two parameters, it was possible to achieve a close match to all the field-permeability data by use of a common set of reservoir properties (elastic properties and matrix-shrinkage parameters) that are consistent with the available field and laboratory data in the literature.

The matching of the field-permeability data in these two regions of the San Juan basin in this study has further validated the updated S&D permeability model (now with variable cleat-volume compressibility). It has also provided theoretical support for the observed near-exponential growth behavior of coalbed permeability in a producing reservoir. Furthermore, the model has shed new light on the permeability behavior: (1) The exponential growth occurs when the reservoir pressure is reduced to a level generally below the permeability-recovery pressure (the reservoir pressure at which the initial permeability is recovered); (2) The reservoir permeability in these two regions would remain relatively flat at reservoir pressures above the permeability recovery pressure.
Identification and Characterization of High-Conductive Layers in Waterfloods
Authors: Izgec B.. , Kabir C.S.. S.
Published: January 2011

This study expands upon the use of modified-Hall analysis (MHA) to discern the characteristics of a high-permeability channel. Briefly, the modified-Hall plot uses three curves involving improved Hall-integral (H-I) and the two derivatives, analytic and numeric. Ordinarily, the derivative curves overlay on the integral curve during matrix injection, but separate lower when fracturing occurs. This work presents a method to identify and characterize high-conductive layers or channels between injector and producer pairs with the MHA. The distance separating the integral and derivative curves provides the required information to quantify channel properties. A simple analytical solution is presented for transforming the separation distance into channel permeabilitythickness product.

The analytic derivative is based on the radial-flow-pattern assumption and the numeric derivative is correlated to the pressure response. Therefore, a comparison of these two curves reveals clues about the maturity of a waterflood at a given time. Several simulated examples verified the channel-property-estimation algorithm and identified the distinctive derivative signatures for channeling and fracturing situations. This method is also useful for identification of wormhole propagation during sand production in unconsolidated formations.
Advanced Gas Material Balance in Simplified Format
Authors: Moghadam Samane , Jeje Oluyemisi , Mattar Louis
Published: January 2011

Material balance has long been used in reservoir engineering practice as a simple yet powerful tool to determine the original gas in place (G). The conventional format of the gas material balance equation is the simple straight line plot of p/Z vs. cumulative gas production (Gp), which can be extrapolated to zero p/Z to obtain G. The graphical simplicity of this method makes it popular. The method was developed for a "volumetric" gas reservoir. It assumes a constant pore volume (PV) of gas and accounts for the energy of gas expansion, but it ignores other sources of energy, such as the effects of formation compressibility, residual fluids expansion and aquifer support. It also does not include other sources of gas storage, such as connected reservoirs or adsorption in coal/shale. In the past, researchers have introduced modified gas material balance equations to account for these other sources of energy. However, the simplicity of the p/Z straight line is lost in the resulting complexity of these equations.

In this paper, a new format of the gas material balance equation is presented, which recaptures the simplicity of the straight line while accounting for all the drive mechanisms. It uses a p/Z** instead of p/Z. The effect of each of the previously mentioned drive mechanisms appears as an effective compressibility term in the new gas material balance equation. Also, the physical meaning of the effective compressibilities are explained and compared with the concept of drive indices. Furthermore, the gas material balance is used to derive a generalized rigorous total compressibility in the presence of all the previously mentioned drive mechanisms, which is important in calculating the pseudotime used in rate transient analysis of production data.
The Influence of Heterogeneity, Wetting, and Viscosity Ratio on Oil Recovery From Vertically Fractured Reservoirs
Authors: Salimi Hamidreza , Bruining Johannes
Published: January 2011

We use upscaling through homogenization to predict oil recovery from fractured reservoirs consisting of matrix columns, also called vertically fractured reservoirs (VFRs), for a variety of conditions. The upscaled VFR model overcomes limitations of the dual-porosity model, including the use of a shape factor. The purpose of this paper is to investigate three main physical aspects of multiphase flow in fractured reservoirs: reservoir wettability, viscosity ratio, and heterogeneity in rock/fluid properties. The main characteristic that determines reservoir behavior is the Péclet number that expresses the ratio of the average imbibition time divided by the residence time of the fluids in the fractures. The second characteristic dimensionless number is the gravity number.

Upscaled VFR simulations, aimed at studying the mentioned features, add new insights. First, we discuss the results at low Péclet numbers. For only small gravity numbers, the effect of contact angle, delay time for the nonequilibrium capillary effect, the heterogeneity of the matrix-column size, and the matrix permeability can be ignored without appreciable loss of accuracy. The ultimate oil recovery for mixed-wet VFRs is approximately equal to the Amott index, and the oil production does not depend on the absolute value of the phase viscosity but on viscosity ratio. However, large gravity numbers enhance underriding, aggravated by large contact angles, longer delay times, and higher viscosity ratios. Layering can lead to an improvement or deterioration, depending on the fracture aperture and permeability distribution. At low Péclet numbers, the fractured reservoir behaves very similarly to a conventional reservoir and depends largely on the viscosity ratio and the gravity number. At high Péclet numbers, after water breakthrough, the oil recovery appears to be proportional to the cosine of the contact angle and inversely proportional to the sum of the oil and water viscosity. In addition, the mixed-wetting effect is more pronounced; there are significant influences of delay time (nonequilibrium effects), matrix permeability, matrix-column size, and the column-size distribution on oil recovery. At low gravity numbers and an effective length/thickness ratio larger than 10, the oil recovery is independent of the vertical-fracture-aperture distribution. For the same amount of injected water, the recovery at low Péclet numbers is larger than the recovery at high Péclet numbers.
The Mechanism of Flow in Reservoir Regions Dominated by Gravity Segregation
Authors: Hales Hugh B. , Cook Kari M.
Published: January 2011

The flow in regions of oil and gas reservoirs that are dominated by gravity segregation can occur through two different mechanisms. First, all reservoir fluid phases, possibly oil, gas and water, might move through the same pores. One or more phases might move upward while the others move countercurrently downward, in the same pores. If such a mechanism were valid, Darcy's law could be applied uniformly over large areas of the reservoir to provide average-phase velocities, just as if the flows were the result of pressure-induced convection. However, a second mechanism is also possible. The phases might be segregated such that some pores carry the upward flowing phases, while other pores carry downward flows. When this mechanism is valid, Darcy's law applies only locally to the upward or downward regions of flow.

The two mechanisms result in substantially different phase velocities. Simulators, including those available commercially, generally assume the first mechanism (i.e., uniform, countercurrent flow throughout each simulation cell). This paper describes an experimental study in which two-phase flow velocities were measured as the phases moved through a bed of small, uniform glass beads, as the result of gravitational forces only. The resulting velocities were more consistent with those predicted for segregated flows of Mechanism 2 compared with those of the commonly assumed homogeneous flows of Mechanism 1. These results suggest that greater accuracy in reservoir simulation may be achieved by including segregated flow in areas of the reservoir where gravity segregation predominates.
Polycentric Polity: Genuine vs. Spurious Federalism
Authors: Eusepi Giuseppe , Wagner Richard E.
Published: January 2011

Federalism is commonly described in contradictory fashion as involving both competition and decentralization. These descriptions may appear similar on the surface, but they emanate from contradictory analytical orientations. Competition entails a polycentric arrangement of competitors where there is no locus of control over the arrangement. In contrast, decentralization is a monocentric arrangement that involves a locus of control. To treat federalism as a method for decentralizing governments leads to a spurious form of federalism because the object that has been identified is not genuinely a competitively organized system of government. Genuine federalism requires a polycentric arrangement that is organized through openly competitive processes. In contrast, the spurious form of federalism allows hierarchy to trump open competition.
Introduction: Ex Uno Plures. Welfare Without Illusion
Authors: Brennan Geoffrey , Eusepi Giuseppe
Published: January 2011

Two competing visions of federalism have long held sway. The first is centered on the idea of an administrative system of delegation based on a geographic partitioning of the polity. The second view sees federalism as a bottom-up structure in which the larger polity is a construct of the smaller polities of which it is composed. In this edited collection, the object is to use these rival visions of a federal structure as a lens through which to analyze the various interconnections between the welfare state and its financing. Specifically, the claim is that the effects of federalism cannot be fully understood without consideration of the vision of federalism that the participants in their various roles adopt. The works collected in this special issue represent a selection of the papers presented at the conference “Ex Uno Plures. Welfare without Illusion,” held in September 2009 at the Faculty of Economics of Sapienza University of Rome, Italy, organized by the European Center for the Study of Public Choice (ECSPC).
Federalism, Budget Deficits and Public Debt: On the Reform of Germany's Fiscal Constitution
Authors: Feld Lars P. , Baskaran Thushyanthan
Published: January 2011

In 2009, new debt restrictions in the Grundgesetz (the German constitution) and in federal legislation passed both chambers of the German parliament by two-thirds majorities, imposing a more rigid debt regime on federal and Länder (states’) fiscal policies than previous constitutional provisions entailed. In this paper, the new provisions are evaluated against the background of the problems of German fiscal federalism that they are supposed to solve, as well as the possible solutions discussed in constitutional economics. We thereby mainly draw on recent evidence from Switzerland. This reform is an important step to remedy the shortcomings of German fiscal federalism, but we argue that it needs to be complemented by tax autonomy for the German Länder.
Raising vs. Leveling in the Social Organization of Welfare
Authors: Wagner Richard E.
Published: January 2011

This paper contrasts raising and leveling as alternative conceptual frameworks regarding the social organization of welfare. At least since Richard Musgrave’s (1959) tripartite organization of the theory of public finance, most fiscal scholars have treated the redistributive activities of governments as necessarily belonging to the national level of government. More significantly perhaps, that literature has treated the problem of promoting welfare as one of leveling incomes through programs of taxing-and-transferring. In contrast, this paper treats the problem of promoting welfare as one of raising incomes. This alternative formulation leads, in turn, to an alternative orientation toward the relationship between federalism and welfare. In particular, there is good reason to think that genuinely competitive federalism offers a sounder institutional framework for the promotion of raising than can redistribution through a central government, mostly because the knowledge that is required for a program of raising is distributed and incapable of meaningful summarization through aggregation.
Federalism as an Effective Antidote to Terrorism
Authors: Frey Bruno S.
Published: January 2011

Many governments as well as terrorist experts see the use of military and police forces as the only way to effectively counter terrorism. The most effective negative sanctions are considered to be military strikes, aggressive actions (including kidnapping and killing) against individuals known or suspected of being terrorists, or against persons supporting and harboring terrorists. Overt and covert military and paramilitary action is also thought advisable to pre-empt and prevent actions by terrorist groups, as well as against states suspected of hosting or tolerating terrorists. This paper argues that decentralization constitutes a powerful antidote as it strongly reduces the incentives for terrorists to attack and because the expected damage suffered is much smaller than in a centralized society. It moreover strengthens society, as economic, political and social decentralization (or polycentricity) is an essential element of a free and vigorous society. This in turn makes a society less vulnerable to terrorist attacks. Indeed, terrorism has no chance of success against a society that actively guards its fundamental liberal institutions, of which decentralized decision-making forms an essential part.
The Global Effects of Subglobal Climate Policies
Authors: Boehringer Christoph , Fischer Carolyn , Rosendahl Knut Einar
Published: January 2011

Individual countries are in the process of legislating responses to the challenges posed by climate change. The prospect of rising carbon prices raises concerns in these nations about the effects on the competitiveness of their own energy-intensive industries and the potential for carbon leakage, particularly leakage to emerging economies that lack comparable regulation. In response, certain developed countries are proposing controversial trade-related measures and allowance allocation designs to complement their climate policies. Missing from much of the debate on trade-related measures is a broader understanding of how climate policies implemented unilaterally (or subglobally) affect all countries in the global trading system. Arguably, the largest impacts are from the targeted carbon pricing itself, which generates macroeconomic effects, terms-of-trade changes, and shifts in global energy demand and prices; it also changes the relative prices of certain energy-intensive goods. This paper studies how climate policies implemented in certain major economies (the European Union and the United States) affect the global distribution of economic and environmental outcomes and how these outcomes may be altered by complementary policies aimed at addressing carbon leakage.
Evaluation of an acute focal epidural mass model to characterize the intracranial pressure-volume relationship in healthy Beagles
Authors: Packer Rebecca A. , Simmons Jeffrey P. , Davis Nichol M. , Constable Peter D.
Published: January 2011

Objective—To characterize the intracranial pressure-volume relationship (ICPVR) in dogs by use of an acute frontal-parietal mass lesion model.

Animals—7 healthy adult female Beagles.

Procedures—Dogs were anesthetized with isoflurane to achieve a surgical plane of anesthesia. A fiberoptic intracranial pressure (ICP) monitor was inserted to a depth of 1 cm in the parenchyma of the right frontal-parietal region of the brain. A Foley balloon-tipped catheter was placed in the epidural space of the left frontal-parietal area through a separate 1-cm burr hole. Baseline measurements were obtained with the balloon deflated. The balloon was then inflated incrementally with 0.5 mL of 0.9% NaCl solution every 10 minutes until ICP exceeded mean arterial blood pressure. Nonlinear regression analysis with 2-factor and 3-factor exponential equations was used to characterize the ICPVR.

Results—The mean baseline ICP was 11 mm Hg, with a 95% confidence interval of 2 to 20 mm Hg. The ICPVR was well characterized by 2-factor or 3-factor exponential equations for all dogs (R2 > 0.93). Balloon volumes of > 1. 2 mL were associated with ICP > 20 mm Hg.

Conclusions and Clinical Relevance—Characterization of the ICPVR may provide clinically useful information regarding the safety of obtaining CSF from the atlanto-occipital space or implantation of brachytherapy catheters and for determining the need for decompressive craniectomy in dogs with acute intracranial disease. High ICP should be suspected in dogs that have an acute frontal-parietal mass lesion estimated to exceed 2% of the brain volume.
Evaluation of changes in haptoglobin and C-reactive protein concentrations caused by freezing of saliva and meat juice samples collected from healthy and diseased pigs
Authors: Gutiérrez Ana M. , Martínez-Subiela Silvia , Cerón Jose J.
Published: January 2011

Objective—To evaluate changes in stability of haptoglobin and C-reactive protein (CRP) concentrations caused by freezing of saliva and meat juice samples.

Animals—16 specific-pathogen-free pigs and 16 pigs with clinical signs of disease.

Procedures—Saliva and diaphragmatic muscle were collected immediately before and after slaughter, respectively. Haptoglobin and CRP concentrations of pooled samples were measured before storage (day 0) and after 7, 15, 30, 60, 120, 210, and 365 days of storage at −20°C and after repeated freezing-thawing cycles (up to 7 times). In a second experiment, addition of a protease-inhibitor cocktail to saliva and storage of saliva samples at −80°C for up to 30 days were assessed for effects on CRP concentrations.

Results—Haptoglobin concentrations in saliva did not change for up to 120 days in samples stored at −20°C, but longer storage times and multiple freezing-thawing cycles increased haptoglobin concentrations. Salivary CRP concentrations decreased significantly after 7 days of storage at −20°C, and addition of a protease-inhibitor cocktail did not improve CRP stability. Lower temperatures limited salivary CRP degradation. In meat juice, haptoglobin and CRP concentrations were stable at −20°C up to 210 days.

Conclusions and Clinical Relevance—Acute-phase protein measurements in saliva should be performed as soon as possible after sample collection. When this is not possible, storage temperature of −80°C is recommended. Acute-phase protein concentrations appeared to be more stable in meat juice samples than in saliva samples. Saliva and meat juice could be used as alternatives to serum for haptoglobin and CRP analysis.
Pharmacokinetics and bioavailability of cefquinome in healthy ducks
Authors: Yuan Liguo , Sun Jian , Wang Rui , Sun Lihua , Zhu Lixiang , Luo Xianyang , Fang Binghu , Liu Yahong
Published: January 2011

Objective—To determine pharmacokinetics and bioavailability of cefquinome administered IV, IM, or PO to healthy ducks.

Animals—Thirty-six 2-month-old Muscovy ducks.

Procedures—Ducks were randomly assigned to 3 groups of 12 birds each for a single IV, IM, or PO administration at a dose of 5 mg/kg. Blood samples were collected before and at various intervals after each administration. Cefquinome concentration was determined by use of high-performance liquid chromatography at 268 nm with a UV detector, and pharmacokinetics were analyzed.

Results—The disposition of cefquinome following IV or IM administration was best described by a 2-compartment model. After IV administration, mean ± SD elimination halflife was 1.57 ± 0.06 hours, clearance value was 0.22 ± 0.02 L/kg·h, and apparent volume of distribution at steady state was 0.41 ± 0.04 L/kg. After IM administration, elimination half-life was 1.79 ± 0.13 hours, peak concentration time was 0.38 ± 0.06 hours, peak drug concentration was 9.38 ± 1.61 μg/mL, and absolute mean ± SD bioavailability was 93.28 ± 13.89%. No cefquinome was detected in plasma after PO administration.

Conclusions and Clinical Relevance—Results indicated that cefquinome was absorbed quickly and had excellent bioavailability after IM administration, but absorption after PO administration was poor.
Evaluation of equine peripheral blood apheresis product, bone marrow, and adipose tissue as sources of mesenchymal stem cells and their differentation potential
Authors: Ahern Benjamin J. , Schaer Thomas P. , Terkhorn Shawn P. , Jackson Karen V. , Mason Nicola J. , Hankenson Kurt D.
Published: January 2011

Objective—To evaluate effects of apheresis on mesenchymal stem cells (MSCs) and compare those MSCs with MSCs obtained from adipose tissue or bone marrow (BM).

Sample Population—Samples obtained from 6 adult horses.

Procedures—Samples of blood from a peripheral vein, adipose tissue, and BM aspirate were obtained from each horse. Samples were processed via apheresis of blood and techniques reported elsewhere for adipose tissue and BM. Cultures were maintained until adherence and subsequently were subjected to differentiation protocols to evaluate adipogenic, osteoblastogenic, and chondrogenic potential.

Results—Apheresis product had a significantly higher mononuclear percentage, higher platelet count, and lower RBC count, compared with values for peripheral blood. No cell adherence to the tissue culture plates was detected for the apheresis product. Adherence was detected for 6 of 6 adipose-derived and 4 of 6 BM-derived samples. Variations in efficiency were detected for differentiation of adipose- and BM-derived cells into adipocytes, chondrocytes, and osteoblasts.

Conclusions and Clinical Relevance—Apheresis was able to concentrate mononuclear cells and reduce RBC contamination. However, the apheresis product was unable to adhere to the tissue culture plates. In matched horses, adipose- and BM-derived MSCs were capable of producing lipids, glycosaminoglycan, and mineral. The BM was vastly superior to adipose tissue as a source of MSCs with osteoblastogenic potential in matched horses. Additional studies will be necessary to optimize apheresis techniques for horses before peripheral blood can be considered a suitable source for multipotential cells for use in cell-based treatments.
Assessment of IgE response and cytokine gene expression in pulmonary efferent lymph collected after ovalbumin inhalation during experimental infection of calves with bovine respiratory syncytial virus
Authors: Gershwin Laurel J. , Anderson Mark L. , Wang Chunbo , Berghaus Londa J. , Kenny Thomas P. , Gunther Robert A.
Published: January 2011

Objective—To assess IgE response and cytokine gene expressions in pulmonary lymph collected from bovine respiratory syncytial virus (BRSV)-infected calves after ovalbumin inhalation.

Animals—Thirteen 7- to 8-week-old calves.

Procedures—The efferent lymphatic duct of the caudal mediastinal lymph node of each calf was cannulated 3 or 4 days before experiment commencement. Calves were inoculated (day 0) with BRSV (n = 7) or BRSV-free tissue culture medium (mock exposure; 6) via aerosolization and exposed to aerosolized ovalbumin on days 1 through 6 and day 15. An efferent lymph sample was collected daily from each calf on days −1 through 16; CD4+ and CD8+ T lymphocyte subsets in lymph samples were enumerated with a fluorescence-activated cell scanner. Expressions of several cytokines by efferent lymphocytes and lymph ovalbumin-specific IgE concentration were measured. Each calf was euthanized on day 16 and then necropsied for evaluation of lungs.

Results—Mean fold increase in ovalbumin-specific IgE concentration was greater in BRSV-infected calves than in mock-infected calves. At various time points from days 4 through 10, percentages of T lymphocyte subsets and CD4+:CD8+ T lymphocyte ratios differed between BRSV-infected calves and day −1 values or from values in mock-infected calves. On days 3 through 5, IL-4 and IL-13 gene expressions in BRSV-infected calves were increased, compared with expressions in mock-infected calves. Lung lesions were consistent with antigen exposure.

Conclusions and Clinical Relevance—In response to the inhalation of aerosolized ovalbumin, BRSV infection in calves appeared to facilitate induction of a T helper 2 cell response and ovalbumin-specific IgE production.
Evaluation of the effects of thiopental, propofol, and etomidate on glomerular filtration rate measured by the use of dynamic computed tomography in dogs
Authors: Chang Jinhwa , Kim Sujin , Jung Joohyun , Lee Heechun , Chang Dongwoo , Lee Youngwon , Lee Inhyung , Yoon Junghee , Choi Mincheol
Published: January 2011

Objective—To evaluate the effects of thiopental, propofol, and etomidate on glomerular filtration rate (GFR) measured by the use of dynamic computed tomography in dogs.

Animals—17 healthy Beagles.

Procedures—Dogs were randomly assigned to receive 2 mg of etomidate/kg (n = 5), 6 mg of propofol/kg (7), or 15 mg of thiopental/kg (5) during induction of anesthesia; anesthesia was subsequently maintained by isoflurane evaporated in 100% oxygen. A 1 mL/kg dosage of a 300 mg/mL solution of iohexol was administered at a rate of 3 mL/s during GFR measurement. Regions of interest of the right kidney were manually drawn to exclude vessels and fatty tissues and highlight the abdominal portion of the aorta. Iohexol clearance per unit volume of the kidney was calculated by use of Patlak plot analysis.

Results—Mean ± SD weight-adjusted GFR of the right kidney after induction of anesthesia with thiopental, propofol, and etomidate was 2.04 ± 0.36 mL/min/kg, 2.06 ± 0.29 mL/min/kg, and 2.14 ± 0.43 mL/min/kg, respectively. However, no significant differences in weight-adjusted GFR were detected among the treatment groups.

Conclusions and Clinical Relevance—Results obtained for the measurement of GFR in anesthetized dogs after anesthetic induction with etomidate, propofol, or thiopental and maintenance with isoflurane did not differ significantly. Therefore, etomidate, propofol, or thiopental can be used in anesthesia-induction protocols that involve the use of isoflurane for maintenance of anesthesia without adversely affecting GFR measurements obtained by the use of dynamic computed tomography in dogs.
Evaluation of the contribution of gyrA mutation and efflux pumps to fluoroquinolone and multidrug resistance in pathogenic Escherichia coli isolates from dogs and cats
Authors: Shaheen Bashar W. , Boothe Dawn M. , Oyarzabal Omar A. , Wang Chengming , Johnson Calvin M.
Published: January 2011

Objective—To investigate the contribution of gyrA mutation and efflux pumps to fluoroquinolone resistance and multidrug resistance among Escherichia coli isolates from dogs and cats.

Sample Population—536 clinical isolates of E coli.

Procedures—Minimum inhibitory concentrations (MICs) were determined for enrofloxacin and 6 other drug classes by use of broth microdilution techniques. Real-time PCR assay was used to determine the mutation in gyrA; Phe-Arg-β-naphthylamide, an efflux pump inhibitor, was used to examine the contribution of efflux pump overexpression.

Results—The MIC for fluoroquinolones increased in a stepwise fashion and was lowest in the absence of mutations, higher with a single point mutation, and highest with 2 point mutations. Level of resistance in the latter category was high (8 times the breakpoint), but this was associated with expression of the AcrAB efflux pump. Inhibition of the efflux pump resulted in a reduction in the MIC to less than the susceptible breakpoint for isolates with an MIC ≤ 4 mg/L, regardless of the presence of a mutation. The greatest magnitude in MIC decrease (MIC was decreased by a factor of > 67 fold) was for isolates with a single mutation but the greatest absolute decrease in MIC (124 mg/L) was for isolates with 2 mutations. Inhibition of the AcrAB efflux pump in isolates characterized by multidrug resistance decreased the MIC of drugs structurally unrelated to fluoroquinolone.

Conclusions and Clinical Relevance—Fluoroquinolone resistance in E coli appeared to be a stepwise phenomenon, with MIC increasing as the number of point mutations in gyrA increased, but high-level resistance and multidrug resistance associated with fluoroquinolone resistance reflected overexpression of the AcrAB efflux pump.
Modulation of cytokine-induced prostaglandin E2 production in cultures of articular chondrocytes obtained from carpal joints of camels (Camelus dromedarius)
Authors: Frondoza Carmelita G. , Heinecke Lowella F. , Grzanna Mark W. , Au Angela Y. , Ownby Stacy L.
Published: January 2011

Objective—To determine whether camel articular chondrocytes can be maintained in tissue culture without phenotype loss and whether the response to cytokine stimulation can be modulated.

Sample Population—Cartilage from 4 carpal joints of healthy adult dromedary camels (Camelus dromedarius).

Procedures—Chondrocytes were evaluated for type II collagen and aggrecan production They were incubated with control media or with 2 test mixtures (alone and then in combination) that have anti-inflammatory activity (avocado-soybean unsaponifiables, glucosamine, and chondroitin sulfate [ie, ASU + GLU + CS] and pentosan polysulfate and N-acetyl glucosamine [ie, PPS + NG]). Cells were then stimulated with interleukin-1β and tumor necrosis factor-α to determine prostaglandin (PG) E2 production and nuclear factor (NF)-κB activation.

Results—Chondrocytes proliferated in media used for propagating equine chondrocytes; they produced type II collagen and aggrecan. Cytokine stimulation induced PGE2 production and translocation of NF-κB. Incubation with each test mixture significantly inhibited PGE2 production. The combination of ASU + GLU + CS and PPS + NG significantly potentiated PGE2 inhibition and disrupted NF-κB translocation, compared with effects for either mixture alone.

Conclusions and Clinical Relevance—Chondrocytes proliferated without loss of the cartilage phenotype. Responses to cytokines were significantly inhibited by the mixtures of ASU + GLU + CS and PPS + NG, which indicated that this response can be modulated. This culture technique can be used to study the functional properties of camel chondrocytes and identify agents that may potentially be used to treat and manage joint inflammation.
Evaluation of pulsatile plasma concentrations of growth hormone in healthy dogs and dogs with dilated cardiomyopathy
Authors: Beijerink Niek J. , Lee Wei M. , Stokhof Arnold A. , Voorhout George , Mol Jan A. , Kooistra Hans S.
Published: January 2011

Objective—To evaluate plasma concentrations of growth hormone (GH) and insulin-like growth factor I (IGF-I) in healthy dogs and large-breed dogs with dilated cardiomyopathy (DCM).

Animals—8 dogs with DCM and 8 healthy control dogs of comparable age and body weight.

Procedures—Blood samples for determination of the pulsatile plasma GH profile were collected from all dogs at 10-minute intervals between 8:00 am and 8:00 pm. Plasma IGF-I concentration was determined in the blood sample collected at 8:00 am.

Results—No significant differences in plasma IGF-I concentrations, basal plasma GH concentration, GH pulse frequency, area under the curve above the zero line and above the baseline for GH, and GH pulse amplitude were found between dogs with DCM and control dogs.

Conclusions and Clinical Relevance—Results did not provide evidence for an association between DCM in dogs and a reduction in plasma concentrations of GH or IGF-I. Therefore, reported positive effects of GH administration are most likely attributable to local effects in the heart.