bluuebunny/crossref_metadata_2025 huggingface dataset:
Studies investigate effects of hydraulic fracturing
Authors: Balcerak Ernie
Published: November 2012

The use of hydraulic fracturing, also known as fracking, to enhance the retrieval of natural gas from shale has been increasing dramatically—the number of natural gas wells rose about 50% since 2000. Shale gas has been hailed as a relatively low‐cost, abundant energy source that is cleaner than coal. However, fracking involves injecting large volumes of water, sand, and chemicals into deep shale gas reservoirs under high pressure to open fractures through which the gas can travel, and the process has generated much controversy. The popular press, advocacy organizations, and the documentary film Gasland by Josh Fox have helped bring this issue to a broad audience. Many have suggested that fracking has resulted in contaminated drinking water supplies, enhanced seismic activity, demands for large quantities of water that compete with other uses, and challenges in managing large volumes of resulting wastewater. As demand for expanded domestic energy production intensifies, there is potential for substantially increased use of fracking together with other recovery techniques for “unconventional gas resources,” like extended horizontal drilling.
Model suggests Earth undergoing true polar wander
Authors: Schultz Colin
Published: November 2012

At various points throughout Earth's history, the planet's solid exterior has drifted about in relation to the planetary rotation axis. This solid body drift, which is known as “true polar wander,” results in a wholesale shift in the orientation of Earth's landmasses and is different from the motion of individual tectonic plates (“tectonic drift”) or of the magnetic pole (“apparent polar wander”). Sorting out when, in which direction, and at what rate the Earth's solid exterior has rotated in this way depends on having a stable frame of reference to which observations of relative motion can be compared. To develop such a frame, researchers rely on hot spots, regions of recurrent volcanism that are known to produce long, largely linear island chains—such as the Hawaiian islands—as an overlying tectonic plate passes overhead. Hot spots are fed by magma plumes from the deep mantle and hence tend to be long‐lived and relatively stable. Hot spots have long been used to understand the motion of tectonic plates.
Spatial distributions of ion pitch angle anisotropy in the near‐Earth magnetosphere and tail plasma sheet
Authors: Wang Chih‐Ping , Zaharia Sorin G. , Lyons Larry R. , Angelopoulos Vassilis
Published: November 2012

We have quantified anisotropy of ion pitch angle distributions observed by the Time History of Events and Macroscale Interactions during Substorms (THEMIS) spacecraft and determined statistically how anisotropy varies with particle energy, as well as spatial distributions and dependences on geomagnetic activity. In the tail plasma sheet, ions from a few keV to a few tens of keV are mostly isotropic. The locations and energy ranges for these isotropic ions and their changes with Dst are consistent with ions being isotropized by current sheet scattering predicted using empirical magnetic field models. Ions of a few hundreds of keV in the tail have cigar‐shaped or unidirectional pitch angle distribution (PAD) and are likely a result of Speiser motion. The majority of ions in the near‐Earth magnetosphere are expected to conserve their first and second adiabatic invariants as they move with pitch angle dependent drift. This gives drift shell splitting, which plays an important role in generating pancake‐shaped PAD observed from ~1 keV up to hundreds of keV. The magnetic local time of the pancake PAD rotates with increasing energy. Loss of near 90° ions due to magnetopause shadowing can further explain the butterfly‐shaped PAD observed at the postmidnight sector at energies above 30 keV. For ions below a few hundreds of eV in the tail plasma sheet and the near‐Earth magnetosphere, their PAD is dominantly bidirectional, which is likely due to ionosphere outflow. High‐energy ions on the dayside become less anisotropic during higher AE, when pitch angle scattering by electromagnetic ion cyclotron waves may play an important role.
Evolution of ensemble data assimilation for uncertainty quantification using the particle filter‐Markov chain Monte Carlo method
Authors: Moradkhani Hamid , DeChant Caleb M. , Sorooshian Soroosh
Published: November 2012

Particle filters (PFs) have become popular for assimilation of a wide range of hydrologic variables in recent years. With this increased use, it has become necessary to increase the applicability of this technique for use in complex hydrologic/land surface models and to make these methods more viable for operational probabilistic prediction. To make the PF a more suitable option in these scenarios, it is necessary to improve the reliability of these techniques. Improved reliability in the PF is achieved in this work through an improved parameter search, with the use of variable variance multipliers and Markov Chain Monte Carlo methods. Application of these methods to the PF allows for greater search of the posterior distribution, leading to more complete characterization of the posterior distribution and reducing risk of sample impoverishment. This leads to a PF that is more efficient and provides more reliable predictions. This study introduces the theory behind the proposed algorithm, with application on a hydrologic model. Results from both real and synthetic studies suggest that the proposed filter significantly increases the effectiveness of the PF, with marginal increase in the computational demand for hydrologic prediction.
Travel time approach to kinetically sorbing solute by diverging radial flows through heterogeneous porous formations
Authors: Severino Gerardo , De Bartolo Samuele , Toraldo Gerardo , Srinivasan Gowri , Viswanathan Hari
Published: November 2012

Diverging radial flow takes place in a heterogeneous porous medium where the log conductivity Y = ln K is modeled as a stationary random space function (RSF). The flow is steady, and is generated by a fully penetrating well. A linearly sorbing solute is injected through the well envelope, and we aim at computing the average flux concentration (breakthrough curve). A relatively simple solution for this difficult problem is achieved by adopting, similar to Indelman and Dagan (1999), a few simplifying assumptions: (i) a thick aquifer of large horizontal extent, (ii) mildly heterogeneous medium, (iii) strongly anisotropic formation, and (iv) large Peclet number. By introducing an appropriate Lagrangian framework, three‐dimensional transport is mapped onto a one‐dimensional domain (τ, t) where τ and t represent the fluid travel and current time, respectively. Central for this approach is the probability density function of the RSF τthat is derived consistently with the adopted assumptions stated above. Based on this, it is shown that the travel time can be regarded as a Gaussian random variable only in the far field. The breakthrough curves are analyzed to assess the impact of the hydraulic as well as reactive parameters. Finally, the travel time approach is tested against a forced‐gradient transport experiment and shows good agreement.
Nanometer positioning accuracy over a long term traveling stage
based on heterodyne interferometry
Authors: Naeim I. , Khodier S.
Published: November 2012

In order to achieve nanometer accuracy, metrologists need to identify the sources of
error and develop solutions to eradicate or minimize their effects. A stabilized low power
dual-frequency laser heterodyne interferometer (ZMI-1000A) designed to measure linear and
angular displacement with nominal measurement resolution 1.24 nm and 0.0025 arcsec,
respectively, is used to achieve measurement of displacements over different travelling
axes by comparison with the electronically reference measurements of the stage over wide
range 500 mm. The repeatability and reversal error of linear stage over the working
distance have agreed opto-electronically and the positioning uncertainty been reduced. A
multivariable framework was implemented for the x-axis due to the cross
coupling between the forward and backward course of the linear stage. Thermal error
reduction is achieved using environmental temperature control (20 ± 0.2 °C)
to help reduce thermal errors.
ASME B89.4.19 standard for laser tracker verification –
experiences and optimisations
Authors: Nasr K.M. , Forbes A.B. , Hughes B. , Lewis A.
Published: November 2012

Laser trackers are becoming the tool of choice for large volume dimensional metrology
applications such as the measurement of aerospace assemblies, power plant structures,
civil engineering structures and terrestrial transportation vehicles. A laser tracker is a
portable coordinate measuring system that tracks a moving target reflector and measures
the position of the target in spherical coordinates (r,
θ, φ). The metrological performance of a laser tracker
is influenced by many factors including: compensation for atmospheric effects, thermal
expansion of the instrument and its mount, thermal distortion of the workpiece or artefact
being measured, the wavelength of the laser radiation, the internal alignment of the
gimbal axes and the linearity and alignment of the internal angular measuring scales. The
most important of these potential error sources, which fundamentally limit the achievable
uncertainty, are the internal mechanical and optical alignments and the quality and
alignment of the angular scales. Several national and international standards exist or are
in the process of being developed for performance verification of laser trackers. ASME
B89.4.19-2006 is one of the established standards used to verify the performance of laser
trackers. The main test relies on measuring a known reference length in a variety of
configurations and ranges and comparison of the observed error (laser tracker measured
length minus reference length) with the specified maximum permissible error (MPE) defined
by the manufacturer. The establishment of an ASME B89.4.19 laser tracker verification
facility at NPL is introduced. We highlight the importance of tracker verification and
discuss the error sources, which contribute to the tracker measurement uncertainty. Some
initial results obtained using this new facility are presented.
A case study approach to investigating end-of-life decision making in an acute health service
Authors: Tan Heather M. , Lee Susan F. , O'Connor Margaret M. , Peters Louise , Komesaroff Paul A.
Published: November 2012

Aim.
To identify end-of-life (EOL) decision making processes for patients with non-cancer illnesses in a major metropolitan hospital.

Methods.
A retrospective review using a case study framework of 47 randomly selected patient records over a 6-month period explored issues in EOL care planning.

Results.
Reviewed charts represented 53% of total deaths in the study period. All patients (aged 66–99) had co-morbid conditions. In 64%, the first record of EOL discussions occurred in the last 24 h of life. Four case groups were identified, ranging from a clear plan developed with patient/family involvement and fully implemented, to no plan with minimal patient/family involvement in decision making. Factors related to clearer EOL care planning according to expressed patient wishes included multiple previous admissions, shorter hospitalisations at EOL, living with a relative and involvement of family in decisions about care.

Conclusion.
This study has shown that the development and effective implementation of EOL plans is associated with the active involvement of both family members and health professionals. It also draws attention to the risks of delaying EOL discussions until late in the illness trajectory or later in life as well as pointing to challenges in acting on EOL developed outside the hospital environment.

What is known about the topic?
End of life (EOL) care planning has been widely discussed in some countries but research into outcomes of such programs has produced variable results both in real outcomes for patients and in satisfaction and ease of application for health professionals. Programs of advance care planning have been introduced in some Australian health services but are yet to produce definitive results.

What does this paper add?
This paper identifies some of the factors that appear to impact on EOL decision making processes in a major Australian metropolitan hospital for patients suffering non-cancer life-limiting illnesses. These data will facilitate the development of more effective EOL care processes in this and other similar healthcare services.

What are the implications for practitioners?
Clear effective processes for making EOL decisions are likely to result in better outcomes for patients, family members and practitioners. A distinctive cluster of patient circumstances may identify risk for poor advance care planning.
Benthic exchange of sedimentary metals (Cd, Cu, Fe, Mn, Ni and Zn) in the Deûle River (Northern France)
Authors: Lourino-Cabana Beatriz , Lesven Ludovic , Billon Gabriel , Denis Lionel , Ouddane Baghdad , Boughriet Abdel
Published: November 2012

Environmental context Exchange processes at the water–sediment interface can release metals to riverine waters, having negative effects on organisms in the water column. We investigate the geochemical processes and metal exchange between the surface sediment and the overlying water under metal contamination conditions. Results suggest that the sediment can be a significant source of metal pollution in aquatic systems, particularly during anoxic events. Abstract Experiments were performed on the Deûle River (Northern France), which is strongly polluted by smelting plants, in the aim to investigate the influence of diagenetic processes and benthic macro-faunal activity on trace metal (Cd, Cu, Ni and Zn) and major metal (Fe, Mn) exchanges occurring at the water–sediment interface. Diffusive metal fluxes were determined from pore water metal concentration gradients measured in sediment cores. Benthic metal fluxes were evaluated using incubation chambers under dark conditions, and by further examining key variables (O2, CO2, redox potential and pH) affecting metal release and sequestration processes. As a whole, it was demonstrated that benthic fluxes were strongly dependent upon medium oxygenation and generation of colloidal iron oxides and hydroxides at the overlying water–sediment interface, raising the possibility of trace-metal adsorption and (co)precipitation.
Cross-sectional survey of older patients’ views regarding multidisciplinary care for chronic conditions in general practice
Authors: Bonney Andrew , Magee Christopher , Pearson Russell
Published: November 2012

The ageing population and increasing prevalence of chronic illness have contributed to the need for significant primary care reform, including increased use of multidisciplinary care and task substitution. This cross-sectional study explores conditions under which older patients would accept having health professionals other than their general practitioner (GP) involved in their care for chronic disease management (CDM). Ten practices were randomly sampled from a contiguous major city and inner regional area. Questionnaires were distributed to consecutive patients aged 60 years and over in each practice. Agency theory was used to inform analyses. Statistical analysis was undertaken using Wald’s test, growth modelling and linear regression, controlling for the clustered design. The response rate was 53% (n = 272). Most respondents (79%) had at least one chronic health condition. Respondents were more comfortable with GP than with practice nurse management in the CDM scenario (Wald’s test = 105.49, P < 0.001). Comfort with practice nurse CDM was positively associated with increased contact with their GP at the time of the visit (β = 0.41, P < 0.001), negatively associated with the number of the respondent’s chronic conditions (β = –0.13, P = 0.030) and not associated with the frequency of other health professional visits. Agency theory suggests that patients employ continuity of care to optimise factors important in CDM: information symmetry and goal alignment. Our findings are consistent with the theory and lend support to ensuring that interpersonal continuity of care is not lost in health care reform. Further research exploring patients’ acceptance of differing systems of care is required.
Clients’ preferred methods of obtaining sexually transmissable infection or HIV results from Sydney Sexual Health Centre
Authors: Martin Lynne , Knight Vickie , Read Phillip J. , McNulty Anna
Published: November 2012

Given the documented benefits of using text messaging (short message service; SMS), the internet and email to deliver sexually transmissible infection (STI) test results, including high acceptability among clients, Sydney Sexual Health Centre (SSHC) aimed to identify which methods our clients preferred for receiving their results, using a cross-sectional survey. There was a preference for SMS (32%) for negative STI results, and for SMS (27%), phone call (27%) and in-person (26%) for negative HIV results. An in-person preference was shown for receiving positive STI results (40%) and positive HIV results (56%, P < 0.001). While many clients would prefer to receive STI test results via text messages or phone call, many also still prefer a return visit, with this preference is dependent on the type and nature of the results. Our study suggests that, ideally, several options for obtaining results should be available.
Unsupervised screening for chlamydia and gonorrhoea in backpacker hostels in Manly, Sydney
Authors: Davies Stephen C. , Shepherd Brooke , Wiig Rebecca , Kaan Iain
Published: November 2012

Young international backpackers frequently have new sexual partners. We conducted a pilot project of unsupervised screening for chlamydia (Chlamydia trachomatis) and gonorrhoea (Neisseria gonorrhoeae) by self-collected specimens at two backpacker hostels in Manly, Sydney. The median age was 24 years for men and 23 years for women. A new sexual partner during travel was reported by 94%, of whom only 20% always using condoms. The prevalence of chlamydia was 11.9% (14.3% of 35 men and 10.2% of 49 women). No cases of gonorrhoea were detected. Half of the dispensed testing kits went missing or were tampered with, and there was spoilage of the receptacle bins, which persisted despite a redesign to a more secure and locked box. While populations such as young backpackers may be a priority group for sexually transmissible infection screening, we advise caution for projects contemplating an unsupervised model.
A Terramycin 200 for Fish (44.09% Oxytetracycline Dihydrate) Treatment Regimen Proposed for the Fluorescent Marking of Rainbow Trout Vertebrae
Authors: Carty Daniel , Bowker James D
Published: November 2012

We evaluated the efficacy of a Terramycin 200 for Fish (TM200; 44.09% oxytetracycline [OTC] dihydrate) treatment regimen proposed for fluorescent marking of the vertebrae of Rainbow Trout Oncorhynchus mykiss. Test fish weighed 36.6 ± 1.9 g (mean ± SD) at the start of treatment. The TM200-treated feed was administered to six tanks of fish at a target dosage of 82.7 mg OTC·kg fish−1·d−1 for 10 d, while nontreated control feed was administered to three tanks of fish (20 fish/tank in each treatment group). After a 22-d posttreatment period, vertebrae were extracted from all fish and were examined for fluorescent marks with a dissecting scope and ultraviolet light. The vertebrae of all treated fish were marked, whereas vertebrae of control fish were not marked. Consequently, the probability of marking success in treated tanks was significantly different from that in control tanks. The 95% CI for the proportion of treated tanks containing one or more nonmarked fish was 0.00 to 0.39. Analysis of treated feed samples revealed that the actual OTC dose administered to treated tanks was 73.4 ± 0.1 mg OTC·kg fish−1·d−1 (mean ± SD; 89% of target). The results indicate that the target TM200 treatment regimen administered in this study is suitable for the marking of Rainbow Trout vertebrae.
Oyster Demographics in a Network of No-Take Reserves: Recruitment, Growth, Survival, and Density Dependence
Authors: Puckett Brandon J. , Eggleston David B.
Published: November 2012

Central to ecology and resource management is knowledge of the spatiotemporal scales at which demographic rates vary and the ecological consequences of demographic variation, such as that due to density dependence. We quantified the spatiotemporal variation in eastern oyster Crassostrea virginica recruitment, density, growth, and survival and assessed density dependence within a network of no-take reserves in Pamlico Sound, North Carolina. From 2006 to 2008, average oyster recruitment and total density increased 15- and fivefold, respectively. The unprecedentedly high oyster densities in certain reserves (up to 6,500/m2 at the end of the study) modified demographic rates such that further density increases were regulated by density-dependent survival. Oyster demographic rates varied significantly among reserves at relatively small spatial scales (20 km). Certain reserves were the strong “recruiters,” others the fast “growers,” and yet others the high “survivors.” Cohort dynamics altered the demographic rank order such that the demographically “best” reserves varied intra- and interannually. From a management perspective, the prevalence of density-dependent survival suggests that the oysters in this system are habitat rather than recruitment limited, which may minimize the utility of stock enhancement programs. Addition of habitat (i.e., artificial reefs) should focus on reserves characterized by high recruitment but density-dependent growth and survival. This study (1) supports the efficacy of marine reserves in rapidly increasing the density and age–size structure of protected species, (2) highlights the need for spatially explicit demographic data to support multifaceted management objectives, and (3) when combined with evidence of reserve larval connectivity, provides support for applying metapopulation concepts to this reserve system.

Received January 27, 2012; accepted July 11, 2012
S1P and the birth of platelets
Authors: Hla Timothy , Galvani Sylvain , Rafii Shahin , Nachman Ralph
Published: November 2012

Recent work has highlighted the multitude of biological functions of sphingosine 1-phosphate (S1P), which include roles in hematopoietic cell trafficking, organization of immune organs, vascular development, and neuroinflammation. Indeed, a functional antagonist of S1P1 receptor, FTY720/Gilenya, has entered the clinic as a novel therapeutic for multiple sclerosis. In this issue of the JEM, Zhang et al. highlight yet another function of this lipid mediator: thrombopoiesis. The S1P1 receptor is required for the growth of proplatelet strings in the bloodstream and the shedding of platelets into the circulation. Notably, the sharp gradient of S1P between blood and the interstitial fluids seems to be essential to ensure the production of platelets, and S1P appears to cooperate with the CXCL12–CXCR4 axis. Pharmacologic modulation of the S1P1 receptor altered circulating platelet numbers acutely, suggesting a potential therapeutic strategy for controlling thrombocytopenic states. However, the S1P4 receptor may also regulate thrombopoiesis during stress-induced accelerated platelet production. This work reveals a novel physiological action of the S1P/S1P1 duet that could potentially be harnessed for clinical translation.
Environmental Risk Analysis: Robustness Is Essential for Precaution
Authors: Sprenger Jan
Published: November 2012

Precaution is a relevant and much-invoked value in environmental risk analysis, as witnessed by the ongoing vivid discussion about the precautionary principle (PP). This article argues (i) against purely decision-theoretic explications of PP; (ii) that the construction, evaluation, and use of scientific models falls under the scope of PP; and (iii) that epistemic and decision-theoretic robustness are essential for precautionary policy making. These claims are elaborated and defended by means of case studies from climate science and conservation biology.
Tragedy of the Anticommons? Intellectual Property and the Sharing of Scientific Information
Authors: Biddle Justin B.
Published: November 2012

Many philosophers argue that the emphasis on commercializing scientific research—and particularly on patenting the results of research—is both epistemically and socially detrimental, in part because it inhibits the flow of information. One of the most important of these criticisms is the “tragedy of the anticommons” thesis. Some have attempted to test this thesis empirically, and many have argued that these empirical tests effectively falsify the thesis. I argue that they neither falsify nor disconfirm the thesis because they do not actually test it. Additionally, I argue that there is other evidence that actually supports the thesis.
Implications of Use of Wright'sFSTfor the Role of Probability and Causation in Evolution
Authors: Abrams Marshall
Published: November 2012

Sewall Wright'sis a mathematical test used to characterize differences between biological populations and identify causes of those differences. I discuss Cockerham and Weir's popular, empirically successful approach to statistical estimation of, arguing that their assumption that actual populations are sampled from an infinite set of counterfactual populations (with a common ancestral population) supports a view of natural selection and genetic drift as distinct causes. I also argue that the way in whichF-statistics and other statistical tests are applied to computer simulations in empirical research shows that selection and drift correspond to differences in objective, causal probabilities.
Spontaneous Symmetry Breaking: Quantum Statistical Mechanics versus Quantum Field Theory
Authors: Fraser Doreen
Published: November 2012

Philosophical analysis of spontaneous symmetry breaking (SSB) in particle physics has been hindered by the unavailability of rigorous formulations of models in quantum field theory (QFT). A strategy for addressing this problem is to use the rigorous models that have been constructed for SSB in quantum statistical mechanics (QSM) systems as a basis for drawing analogous conclusions about SSB in QFT. On the basis of an analysis of this strategy as an instance of the application of the same mathematical formalism to different domains and as an instance of drawing analogies between domains, I conclude that certain structural explanations can be exported from QSM to QFT but that causal explanations cannot.
Optical and ferroelectric properties of ruthenium-doped BaTiO3 nanocubes
Authors: Sarkar Babusona , Chakrabarti Kaushik , Das Kajari , De S K
Published: November 2012

Structural, optical, dielectric and ferroelectric properties of Ru-doped BaTi1−x
Ru
x
O3(x = 0.01, 0.03, 0.05, 0.07, 0.10) nanocubes have been investigated. The average size of nanocube obtained from Rietveld refinement is in the range 35–60 nm. The incorporation of Ru leads to a mixed tetragonal and cubic crystalline phases in doping concentration range 5–7%. Optical band gap changes from 3.2 to 2.74 eV with increase in Ru concentration. Replacement of Ti with Ru quenches band-edge emission and enhances defect emission intensity. Optical absorption and emission spectra have been interpreted in terms of oxygen vacancy. Ruthenium 4d orbital plays a crucial role to improve dielectric constant and diminish ferroelectric Curie temperature. The combined effect of Ru dopant and size gives rise to complex variation of Curie temperature.
On joint estimates for maximal functions and singular integrals on weighted spaces
Authors: Reguera Maria Carmen , Scurry James
Published: November 2012

We consider a conjecture attributed to Muckenhoupt and Wheeden which suggests a positive relationship between the continuity of the Hardy-Littlewood maximal operator and the Hilbert transform in the weighted setting. Although continuity of the two operators is equivalent for

A
p

A_p

weights with

1
>
p
>
∞

1 > p > \infty

, through examples we illustrate this is not the case in more general contexts. In particular, we study weights for which the maximal operator is bounded on the corresponding

L
p

L^p

spaces while the Hilbert transform is not. We focus on weights which take the value zero on sets of nonzero measure and exploit this lack of strict positivity in our constructions. These types of weights and techniques have been explored previously by the first author and independently with C. Thiele.
Factors Affecting Farmers' Hedging Decisions
Authors: Shapiro B.I. , Brorsen B. Wade
Published: November 2012

Few farmers use futures markets in spite of theoretical research that says they should and educational efforts to get them to do so. This paper sought to determine the factors that explain why a sample of Indiana farmers use futures markets. Survey results showed that on average futures markets were perceived to both reduce risk and increase income. The most important factors explaining the use of futures markets were the individual's perception of the ability of futures markets to reduce risk and the individual's debt position.
An Analysis of the Agricultural and Trade Policy Preferences of Iowa Farm Operators
Authors: Edelman Mark A. , Lasley Paul
Published: November 2012

Many previous farm policy preference surveys were conducted before full implementation of the Food Security Act of 1985. This post‐implementation analysis of farm policy preferences of Iowa farm operators found high support for continuation of current programs and many of the new provisions included in the 1985 FSA. Also, there was strong support for payment limitations and all international trade policy directions identified. Nine socioeconomic characteristics were analyzed to determine if they were associated with farm policy preferences. Although many of the correlations were significant, the degrees of association were relatively low.
Public School Resources in Rural Communities: An Examination of Size Economies in Eastern Nebraska Public School Districts
Authors: Forsythe Kenneth W. , Yanagida John F. , Johnson Bruce B.
Published: November 2012

An average total cost function for 53 selected public school districts in Eastern Nebraska over the time period 1981–84 is estimated. A quality of educational services index is developed and used to account for quality differences between school districts over time. Using a covariance model to pool time series and cross‐sectional data, significant economies of size were found. The empirical findings also are discussed in regard to the issue of school consolidation.
Targeting Soil Conservation Incentive Payments
Authors: Setia Parveen P. , Osborn C. Tim
Published: November 2012

An economic criterion to identify the minimum variable incentive payment rates needed to induce farmers to adopt conservation practices is presented. The Erosion Productivity Economics Model (EPEM) was used to compare various conservation management systems to achieve established levels of erosion control. Findings suggest that there could be substantial net savings by targeting and recognizing the productivity impacts.
Returns to Swine Research in Canada
Authors: Hout Marie-France , Fox Glenn , Brinkman George
Published: November 2012

This paper examines the economic impact of swine research undertaken by Agriculture Canada from 1968 to 1984. The economic surplus approach is used to estimate the returns to this research and to determine the distribution of benefits between producers and consumers. The ex ante and ex post approaches to measuring changes in producer surplus are compared. The impact of the marginal excess burden of taxes on measures of net benefits from research is examined. The internal rate of return to expenditures on swine research was found to be between 45 percent and 50 percent at the margin. About 85 percent of the benefits accrued to Canadian hog producers. Swine research expenditures in the United States were found to have a statistically significant effect on Canadian hog production.
Dairy Cow Replacement Decisions under Alternative Tax Codes
Authors: Schnitkey Gary D. , Arbaugh Dale
Published: November 2012

Optimal planned replacement lactations (OPRLs) for dairy cows are determined under scenarios representing (1) a no tax situation, (2) the 1986 tax code, (3) the 1987 tax code when heifer raising costs are expensed and (4) the 1987 tax code when heifer raising costs are capitalized. Under each tax scenario, OPRLs are found when replacement heifers are raised and when replacement heifers are purchased. Taxes have impacts on OPRLs, particularly when replacement heifers are raised. When replacements are raised, results indicate that farmers selecting the capitalizing option should voluntarily replace cows later than farmers selecting the expensing option.
Effects of a Beef Grade Change on Choice and Select Slaughter Cattle Prices
Authors: Marsh John M.
Published: November 2012

Distributed lags are used to estimate the conditional price effects of quality grade substitution and ungraded beef on USDA Choice and Select grade slaughter cattle. The results show that Choice beef production and ungraded production demonstrate large class price effects. When revising USDA Choice grade to accommodate reduced marbling, potential reclassification of ungraded beef plays a major role. The results show a decrease in Choice price with a slight increase in Select price and a reduction in the price premium paid for Choice steers. Overall, grade modifications emphasizing leaner beef would not necessarily benefit cattle producers unless there was a compensating change in demand and/or a reduction in feeding costs.
Using a Decision Support Framework to Evaluate Forecasts
Authors: Park Wayne I. , Garcia Philip , Leuthold Raymond M.
Published: November 2012

The paper examines the relationship between statistical measures of forecast accuracy and decision support for determining the most useful forecast method. A decision framework is examined with forecasts used to guide trading decisions of a hog producer, buyer and speculator in the hog market. Out‐of‐sample forecasts from various models are evaluated using mean square error and returns from trading decisions under risk‐efficiency criteria. The results emphasize the importance of evaluating forecasts within specific decision‐making situations.
Biotechnology, Anticipated Productivity Increases and U.S. Dairy Policy
Authors: McGuckin J. Thomas , Ghosh Soumen
Published: November 2012

A major difficulty with the U.S. milk price support program is the instability in fiscal budgeting caused by the rapid technological change occurring in the industry. Further, the introduction of foreseeable new technologies such as synthetic bovine Somatotropin (bST) will compound the levels and costs of government purchases of milk after the technology is introduced in 1990. In this paper, an optimal control model is developed to stabilize government purchases of surplus milk in anticipation of bST. Results indicate that the current policies of Food Security Act of 1985 do not adequately anticipate the introduction of bST, and this will present a large dilemma for dairy policy. Provisions of FSA are adequate to stabilize government purchases of milk at acceptable levels only if bST is not introduced. Either the technology must be restricted, possibly through product taxes, or support prices must be lowered dramatically. Even with lower support prices, CCC purchases may still climb to high levels (15 billion pounds), depending on the rate of adoption.
Students Form Commodity Pool to Learn about the Futures Market
Authors: Tierney William I.
Published: November 2012

Commodity paper trading games are widely used to give students experience in trading. One weakness of these games is that there are no monetary and only minor emotional consequences resulting from the students' trades. To simulate actual trading more realistically, a Student Commodity Pool (SCP) was organized at Kansas State University. Twenty‐nine students contributed $100 each to a pool account, formed groups to research and present trade recommendations and then traded actual futures and options contracts. As an experiential learning method, most students gave the class high marks. Other instructors may be able to establish SCPs with approval from the Commodity Futures Trading Commission.
Development of Financial Relationships Within Farm Level Simulation Models
Authors: Nutt Perry J. , Skees Jerry R.
Published: November 2012

Monte Carlo simulation is used to examine the effects of various financial relationships upon the growth rate in equity for farms with different levels of debt. A method is proposed for establishing financial relationships whereby comparable growth rates for farms with different debt will occur. The results demonstrate that financial relationships are important when comparing farms with different debt and when developing inferences about policy alternatives at the farm level.
An Economic Analysis of Producers' Decisions Regarding Insect Control in Stored Grain
Authors: Anderson Kelline , Schurle Bryan , Reed Carl , Pedersen John
Published: November 2012

The quantity of grain in storage has been exceptionally high through much of the early 1980s. As a result, the effect of insect activity on quality of grain that is stored for long periods of time has become a major concern. The purpose of this study was to analyze producer choices regarding treatments for control of insects in stored grain. A second degree stochastic dominance criterion was used to compare three treatments. In more than 80% of the comparisons, a protectant (malathion) was in the efficient set, which means that it could be selected by a risk‐averse individual. In over 65% of the comparisons, a minimum treatment was in the efficient set. Treatment by fumigating was selected to remain in the efficient set in only 34% of the comparisons. Data from this study (before the implementation of the May 1988 regulations of the Federal Grain Inspection Service regarding insect infestation and insect‐damaged kernels) suggest that elevator discounts were not consistent nor large enough to encourage farmers to incur large costs for controlling insects.
A Portfolio Analysis of Returns to Farm Equity and Assets
Authors: Crisostomo Mario F. , Featherstone Allen M.
Published: November 2012

A portfolio analysis was used to determine the optimal investment into alternative types of Kansas farms by nonfarm investors. Dairy and crop farms would enter the optimal portfolio if asset values would fall by 4.8 percent and 31.3 percent, respectively. Study results show that swine and irrigated crop farms have earned competitive return rates with common stocks and T‐Bills from 1973–1985. Results suggest that many Kansas farmers would have been better off with less debt. Arrangements to transfer nonfarm equity into agriculture will continue to be an area needing study.
A Classic Economies of Size Analysis on Average School Costs: An Iowa Case Study
Authors: Edelman Mark A. , Knudsen James J.
Published: November 2012

This study found size economies in Iowa school districts. An asymmetric U‐shaped cost curve provided the best fit. Costs were minimized at $2,952 per pupil and 2,442 pupils, but most size economies—within $100 per pupil—were achieved at 800 to 900 pupils. Implications for school reorganization were discussed.
An Evaluation of Differences between Cash and Accrual Income for Illinois Farms
Authors: Newport Scott M. , Lins David A.
Published: November 2012

Net farm income is a measure of farm financial performance frequently used by farmers, leaders, and financial consultants. However, distortions may arise if cash income is used to measure performance. Results of this study suggest large differences between cash and accrual measures of net farm income and these differences vary by farm type, size, level of growth and degree of financial stress. Tax savings due to the cash method are also found to be large, especially on farms undergoing expansion.
An Empirical Analysis of Cash and Futures Grain Price Relationships in the North Central Region
Authors: Thompson S.R. , Eales J.S. , Hauser R.J.
Published: November 2012

This paper investigates grain price relationships in the north central region by analyzing weekly prices for corn and soybeans at cash and futures markets. First differences in cash prices are compared statistically to first differences in futures prices. Next, the relationship of spatial basis changes between cash market locations is analyzed. The results indicate that cash and futures markets are not a constellation of one united grain market. Identifiable differences in price relationships exist across markets and time periods. The results have implications for hedging strategies as well as for consideration of the performance of Chicago as a delivery location for futures contracts.
Stability analysis of phylogenetic trees
Authors: Sheikh Saad I. , Kahveci Tamer , Ranka Sanjay , Gordon Burleigh J.
Published: November 2012

Motivation: Phylogenetics, or reconstructing the evolutionary relationships of organisms, is critical for understanding evolution. A large number of heuristic algorithms for phylogenetics have been developed, some of which enable estimates of trees with tens of thousands of taxa. Such trees may not be robust, as small changes in the input data can cause major differences in the optimal topology. Tools that can assess the quality and stability of phylogenetic tree estimates and identify the most reliable parts of the tree are needed.

Results: We define measures that assess the stability of trees, subtrees and individual taxa with respect to changes in the input sequences. Our measures consider changes at the finest granularity in the input data (i.e. individual nucleotides). We demonstrate the effectiveness of our measures on large published datasets. Our measures are computationally feasible for phylogenetic datasets consisting of tens of thousands of taxa.

Availability: This software is available at http://bioinformatics.cise.ufl.edu/phylostab

Contact:  sheikh@cise.ufl.edu
Veiling*
Authors: Carvalho Jean-Paul
Published: November 2012

Veiling among Muslim women is modeled as a commitment mechanism that limits temptation to deviate from religious norms of behavior. The analysis suggests that veiling is a strategy for integration, enabling women to take up outside economic opportunities while preserving their reputation within the community. This accounts for puzzling features of the new veiling movement since the 1970s. Veiling also has surprising effects on the intergenerational transmission of values. Compulsory veiling laws can lead to a decline in religiosity. Bans on veiling can inhibit social integration and increase religiosity.
Unconditional Convergence in Manufacturing
*
Authors: Rodrik Dani
Published: November 2012

Unlike economies as a whole, manufacturing industries exhibit strong unconditional convergence in labor productivity. The article documents this at various levels of disaggregation for a large sample covering more than 100 countries over recent decades. The result is highly robust to changes in the sample and specification. The coefficient of unconditional convergence is estimated quite precisely and is large, at between 2–3% in most specifications and 2.9% a year in the baseline specification covering 118 countries. The article also finds substantial sigma convergence at the two-digit level for a smaller sample of countries. Despite strong convergence within manufacturing, aggregate convergence fails due to the small share of manufacturing employment in low-income countries and the slow pace of industrialization. Because of data coverage, these findings should be as viewed as applying to the organized, formal parts of manufacturing.
Occupational therapists perspectives of factors influencing chronic pain management
Authors: van Huet Helen , Innes Ev , Stancliffe Roger
Published: November 2012

Aim

This article explores factors that contribute to clients' chronic pain management from an occupational therapy perspective.

Method

Nine occupational therapists from Australia and New Zealand who worked in this practice area were interviewed. Qualitative method of narrative inquiry was used to analyse the therapists' practice narratives to determine their view of how clients manage their chronic pain.

Results

Among many themes, significant agentic (positive management) themes and victimic (negative themes related to non‐management) emerged. Agentic themes were related to conceptual categories of being: the importance of maintaining valued roles and having good social support; to knowing: accepting the long‐term nature of pain and being ready to change thinking about pain, and to doing. These categories included strategies such as setting realistic goals, pacing activity and using relaxation. Victimic themes were also related to being: losing valued roles, having depression and receiving compensation and to knowing: being fearful, looking for a cure or not knowing what to expect. Victimic doing themes related to: being unable to set goals and being unable to use strategies. These themes and categories form the basis of proposed agentic and victimic conceptual models of factors for occupational therapists to address in pain management programmes.

Conclusions

As acceptance and readiness for change were consistently mentioned in all narratives, the place of contextual cognitive‐behavioural approaches to pain management is also raised as a viable alternative to standard cognitive‐behavioural therapy, currently used in most chronic pain practice.
Spatial and temporal variation in the control failure likelihood of the tomato leaf miner, Tuta absoluta
Authors: Gontijo P.C. , Picanço M.C. , Pereira E.J.G. , Martins J.C. , Chediak M. , Guedes R.N.C.
Published: November 2012

Insecticide resistance is frequently associated with field control failure, but such an assessment of its likelihood seldom occurs. This phenomenon is a potential cause of the control failure of the tomato leaf miner Tuta absoluta (Lepidoptera: Gelechiidae); therefore we surveyed insecticide resistance as the control failure likelihood for a duration of 7 years in 20 field populations of this species. The insecticide label rate was used as the discriminating concentration, and the minimum efficacy threshold required for insecticides in Brazil (i.e. 80% efficacy) was the targeted efficacy. The spatial and temporal variations of the control failure likelihood were also assessed, as was the potential influence of land topography for the area‐wide pattern observed. Most populations of T. absoluta were susceptible to abamectin, chlorfenapyr and spinosad and not to bifenthrin, triflumuron and teflubenzuron. The indoxacarb susceptibility varied in space and time. Spatial dependence was observed for abamectin and indoxacarb. The control failure likelihood of T. absoluta was higher for bifenthrin, triflumuron and teflubenzuron. A flat topography and the wind direction may favour the spread of the control failure likelihood and should be considered in designing pest management programs for T. absoluta.