bluuebunny/crossref_metadata_2025 huggingface dataset:
Perceptually Linear Parameter Variations
Authors: Lindow Norbert , Baum Daniel , Hege Hans‐Christian
Published: June 2012

Most visual analysis tasks require interactive adjustment of parameter values. In general, a linear variation of a parameter, using for instance a GUI slider, changes the visual result in a perceptually non‐linear way. This hampers interactive adjustment of parameters, especially in regions where rapid perceptual changes occur. Selecting a good parameter value therefore remains a time‐consuming and often difficult task. We propose a novel technique to build a non‐linear function that maps a new parameter to the original parameter. By prefixing this function to the original parameter and using the new parameter as input, a linear relationship between input and visual feedback is obtained. To construct the non‐linear function, we measure the variation of the visual result using image metrics. Given a suitable perceptual image metric, perceptually linear image variations are achieved. We demonstrate the practical utility of our approach by implementing two common image metrics, a perceptual and a non‐perceptual one, and by applying the method to a few visual analysis tasks.
NoRM: No‐Reference Image Quality Metric for Realistic Image Synthesis
Authors: Herzog Robert , Čadík Martin , Aydčin Tunç O. , Kim Kwang In , Myszkowski Karol , Seidel Hans‐P.
Published: June 2012

Synthetically generating images and video frames of complex 3D scenes using some photo‐realistic rendering software is often prone to artifacts and requires expert knowledge to tune the parameters. The manual work required for detecting and preventing artifacts can be automated through objective quality evaluation of synthetic images. Most practical objective quality assessment methods of natural images rely on a ground‐truth reference, which is often not available in rendering applications. While general purpose no‐reference image quality assessment is a difficult problem, we show in a subjective study that the performance of a dedicated no‐reference metric as presented in this paper can match the state‐of‐the‐art metrics that do require a reference. This level of predictive power is achieved exploiting information about the underlying synthetic scene (e.g., 3D surfaces, textures) instead of merely considering color, and training our learning framework with typical rendering artifacts. We show that our method successfully detects various non‐trivial types of artifacts such as noise and clamping bias due to insufficient virtual point light sources, and shadow map discretization artifacts. We also briefly discuss an inpainting method for automatic correction of detected artifacts.
Centroidal Voronoi Tessellation of Line Segments and Graphs
Authors: Lu Lin , Lévy Bruno , Wang Wenping
Published: June 2012

Centroidal Voronoi Tessellation (CVT) of points has many applications in geometry processing, including re‐meshing and segmentation, to name but a few. In this paper, we generalize the CVT concept to graphs via a variational characterization. Given a graph and a 3D polygonal surface, our method optimizes the placement of the vertices of the graph in such a way that the graph segments best approximate the shape of the surface. We formulate the computation of CVT for graphs as a continuous variational problem, and present a simple, approximate method for solving this problem. Our method is robust in the sense that it is independent of degeneracies in the input mesh, such as skinny triangles, T‐junctions, small gaps or multiple connected components. We present some applications, to skeleton fitting and to shape segmentation.
Medial Kernels
Authors: Berger Matthew , Silva Claudio T.
Published: June 2012

We introduce the medial kernel, an association measure which provides for a robust construction of volume‐aware distances defined directly on point clouds. The medial kernel is a similarity measure defined as the likelihood of two points belonging to a common interior medial ball. We use the medial kernel to construct a random walk on the point cloud, where movement in the walk is restricted to regions containing similar medial balls. Our distances are defined as the diffusion distances of this random walk, assigning low distance to points belonging to similar medial regions. These distances allow for a robust means of processing incomplete point clouds, capable of distinguishing nearby yet separate undersampled components, while also associating points which are far in Euclidean distance yet mutually share an interior volume. We leverage these distances for several applications: volumetric part segmentation, the construction of function bases, and reconstruction‐by‐parts – a surface reconstruction method which adheres to the medial kernel.
A Cell‐Based Light Interaction Model for Human Blood
Authors: Yim D. , Baranoski G.V.G. , Kimmel B.W. , Chen T.F. , Miranda E.
Published: June 2012

The development of predictive appearance models for organic tissues is a challenging task due to the inherent complexity of these materials. In this paper, we closely examine the biophysical processes responsible for the appearance attributes of whole blood, one the most fundamental of these materials. We describe a new appearance model that simulates the mechanisms of light propagation and absorption within the cellular and fluid portions of this specialized tissue. The proposed model employs a comprehensive, and yet flexible first principles approach based on the morphological, optical and biochemical properties of blood cells. This approach allows for environment driven changes in the cells' anatomy and orientation to be appropriately included into the light transport simulations. The correctness and predictive capabilities of the proposed model are quantitatively and qualitatively evaluated through comparisons of modeled results with actual measured data and experimental observations reported in the scientific literature. Its incorporation into rendering systems is illustrated through images of blood samples depicting appearance variations controlled by physiologically meaningful parameters. Besides the contributions to the modeling of material appearance, the research presented in this paper is also expected to have applications in a wide range of biomedical areas, from optical diagnostics to the visualization and noninvasive imaging of blood‐perfused tissues.
Satisfaction with Democracy in Multi-ethnic Countries: The Effect of Representative Political Institutions on Ethnic Minorities
Authors: Ruiz-Rufino Rubén
Published: June 2012

Using survey data collected between 1997 and 2001 in ten post-communist countries, I test a set of hypotheses that explain satisfaction with democracy among members of the main ethnic minority groups within each country. First, I test whether political representation, per se, has any effect at all. Second, I examine the relationship between the type of political system and the capacity of an ethnic minority to participate in the decision-making process. In particular, I show that those minorities which have a voice in parliamentary democracies are more satisfied than other minorities which act in political systems with a more powerful president. Finally, I focus on the proportionality of an electoral system. In this sense, I show how more proportional electoral systems increase satisfaction with democracy for those minorities that either do not have any political representation at all or whose political ethnic party is small. When the ethnic political party is large, then less proportional electoral systems boost satisfaction with democracy.
Unilateral Climate Policy and Competitiveness: Economic Implications of Differential Emission Pricing
Authors: Böhringer Christoph , Alexeeva‐Talebi Victoria
Published: June 2012

Unilateral climate policy raises concerns about international competitiveness and emission leakage that result in preferential regulatory treatment of domestic energy‐intensive and trade‐exposed (EITE) industries. Our applied analysis of unilateral EU abatement illustrates the potential pitfalls of climate policy design which narrowly focuses on competitiveness concerns about EITE industries. The sector‐specific gains of differential emission pricing in favour of these branches must be traded off with the additional burden imposed on other industries. From the perspective of the unilaterally abating region preferential EITE emission pricing can induce non‐negligible excess cost as policy concedes (too) low emission prices to EITE industries and thereby foregoes relatively cheap abatement options in these sectors. With respect to global cost‐effectiveness of unilateral climate policy, we find that differential emission pricing in favour of EITE industries can reduce emission leakage and thereby provide global cost savings compared with uniform pricing. However, the scope for cost savings is limited and may change into substantial cost increases if unilateral reduction targets are moderate and EITE industries get close to exemptions.
ARBITRAGE‐FREE BILATERAL COUNTERPARTY RISK VALUATION UNDER COLLATERALIZATION AND APPLICATION TO CREDIT DEFAULT SWAPS
Authors: Brigo Damiano , Capponi Agostino , Pallavicini Andrea
Published: June 2012

We develop an arbitrage‐free valuation framework for bilateral counterparty risk, where collateral is included with possible rehypothecation. We show that the adjustment is given by the sum of two option payoff terms, where each term depends on the netted exposure, i.e., the difference between the on‐default exposure and the predefault collateral account. We then specialize our analysis to credit default swaps (CDS) as underlying portfolios, and construct a numerical scheme to evaluate the adjustment under a doubly stochastic default framework. In particular, we show that for CDS contracts a perfect collateralization cannot be achieved, even under continuous collateralization, if the reference entity’s and counterparty’s default times are dependent. The impact of rehypothecation, collateral margining frequency, and default correlation‐induced contagion is illustrated with numerical examples.
THE AFFINE LIBOR MODELS
Authors: Keller‐Ressel Martin , Papapantoleon Antonis , Teichmann Josef
Published: June 2012

We provide a general and flexible approach to LIBOR modeling based on the class of affine factor processes. Our approach respects the basic economic requirement that LIBOR rates are nonnegative, and the basic requirement from mathematical finance that LIBOR rates are analytically tractable martingales with respect to their own forward measure. Additionally, and most importantly, our approach also leads to analytically tractable expressions of multi‐LIBOR payoffs. This approach unifies therefore the advantages of well‐known forward price models with those of classical LIBOR rate models. Several examples are added and prototypical volatility smiles are shown. We believe that the CIR process‐based LIBOR model might be of particular interest for applications, since closed form valuation formulas for caps and swaptions are derived.
Visual Management Studies: Empirical and Theoretical Approaches*
Authors: Bell Emma , Davison Jane
Published: June 2012

The field of visual research in management studies is developing rapidly and has reached a point of maturity where it is useful to bring together and evaluate existing work in this area and to critically assess its current impact and future prospects. Visual research is broadly defined to encompass a variety of forms, including pictures, graphs, film, web pages and architecture. It also incorporates work from several sub‐disciplines (organization studies, marketing, accounting, human resources, tourism and IT), and includes research based on pre‐existing visual material and studies that use researcher‐generated visual data. The authors begin by considering the growing recognition of the visual turn in management research as a counterweight to the linguistic turn, while also discussing reasons for resistance to visual approaches. Next, they review research that uses visual methods to study management and organization and suggest that visual management studies may be categorized according to whether methods used are empirically driven or theory based. This categorization highlights the philosophical, theoretical and interdisciplinary underpinnings of visual management studies. It also enables the visual to be accorded a status equivalent to linguistic meaning, through dispelling the realist assumptions that have impeded analytical development of visual management studies to date.
Population genetic structure of a threatened tortoise across the south‐eastern United States: implications for conservation management
Authors: Clostio R. W. , Martinez A. M. , LeBlanc K. E. , Anthony N. M.
Published: June 2012

The progressive loss and fragmentation of longleaf pine forests throughout the southeastern United States has led to severe declines in habitat specialists such as the federally listed gopher tortoise Gopherus polyphemus. However, little is known of the range‐wide historical genetic structure of this species or how habitat loss may have impacted the genetic diversity of this species over time. As genetic data are lacking in many parts of the gopher tortoise range, management of federally listed populations in Louisiana and Mississippi have been based on conservation units delineated by rivers. However, this current management strategy has been formulated without any knowledge of how riverine barriers might relate to genetic population structure. Here, we examine variability of mitochondrial and nuclear microsatellite markers in gopher tortoise populations across their natural range in the southeastern United States. Results from the mitochondrial data showed a historical phylogenetic break that is coincident with the Apalachicola River and a novel population assemblage located within western Georgia. Genetic structure based on microsatellite loci revealed high levels of genetic differentiation in some regions and a pattern of isolation by distance at two spatial scales. We also find that rivers across the federally listed portion of the range, do not significantly influence gene flow. Coalescent analyses of population demographic change in gopher tortoises indicate evidence of an ancient and severe population decline at sites across the range. Findings from this study provide important information that will aid in the identification of distinct population units for management and in the formulation of recommendations for the future maintenance of genetic diversity in this species.
Comparison of free amino acids and volatile components in three fermented milks
Authors: IRIGOYEN AURORA , ORTIGOSA MARIA , GARCÍA SUSANA , IBÁÑEZ FRANCISCO C , TORRE PALOMA
Published: June 2012

Free amino acids (FAAs) and volatile components were analysed in commercial samples of yoghurt and Actimel® drink as well as laboratory‐made kefir. The lysine and cysteine were the principal amino acids and accounted for about 70% of the total FAAs in all the samples. However, the amino acid profiles in the different fermented milk products differed: on the whole values for most of the amino acids were observed to be significantly higher in the Actimel® samples. A total of 50 volatile components were identified. The largest number of volatiles were found in the kefir. Ethanol, 2,3‐ butanodione and 3‐hidroxybutan‐2‐one were the most prevalent volatile components, with ethanol significantly higher in the kefir samples.
Evaluation of trichloromethane formation from chlorine‐based cleaning and disinfection agents in cow’s milk
Authors: SIOBHAN RYAN , DAVID GLEESON , KIERAN JORDAN , AMBROSE FUREY , BERNADETTE O’ BRIEN
Published: June 2012

The development of trichloromethane (TCM) in milk can result from the use of chlorine‐based detergent solutions during the milk production process. Different factors affecting the development of TCM in milk were investigated. Gas chromatography with electron capture detector was the method of analysis. Combining milks of different TCM levels resulted in milk TCM levels similar to that calculated mathematically. Increased chlorine concentration in the detergent and reduced rinse water volume resulted in increased TCM concentrations (P < 0.05) in milk, while the addition of chlorine to the rinse water also increased (P < 0.001) milk TCM.
Questioning the benefits that coloured overlays can have for reading in students with and without dyslexia
Authors: Henderson Lisa M. , Tsogka Natassa , Snowling Margaret J.
Published: June 2012

Visual stress (the experience of visual distortions and discomfort during prolonged reading) is frequently identified and alleviated with coloured overlays or lenses. Previous studies have associated visual stress with dyslexia and as a consequence, coloured overlays are widely distributed to children and adults with reading difficulty. However, this practice remains controversial. We investigated whether overlays have advantageous and reliable benefits for reading in undergraduate students with and without dyslexia. Both groups read jumbled text faster with a coloured overlay than without. The dyslexic group did not show greater gains than controls, despite reporting significantly more symptoms of visual stress. However, coloured overlays did not improve reading rate or comprehension of connected text. The improvement in reading speed with an overlay was not reliable and was significantly reduced at retesting for dyslexic students. These results question the value of coloured overlays as a tool for identifying visual stress and as a form of remediation for the reading difficulties associated with dyslexia.
Inhibition of NMDA‐type glutamate receptors induces arousal from torpor in hibernating arctic ground squirrels (Urocitellus parryii)
Authors: Jinka Tulasi R. , Rasley Brian T. , Drew Kelly L.
Published: June 2012

J. Neurochem. (2012) 122, 934–940.

Hibernation is an adaptation to overcome periods of resource limitation often associated with extreme climatic conditions. The hibernation season consists of prolonged bouts of torpor that are interrupted by brief interbout arousals. Physiological mechanisms regulating spontaneous arousals are poorly understood, but may be related to a need for gluconeogenesis or elimination of metabolic wastes. Glutamate is derived from glutamine through the glutamate–glutamine cycle and from glucose via the pyruvate carboxylase pathway when nitrogen balance favors formation of glutamine. This study tests the hypothesis that activation of NMDA‐type glutamate receptors (NMDAR) maintains torpor in arctic ground squirrel (arctic ground squirrel (AGS); Urocitellus parryii). Administration of NMDAR antagonists MK‐801 (5 mg/kg, i.p.) that crosses the blood–brain barrier and AP5 (5 mg/kg, i.p.) that does not cross the blood–brain barrier induced arousal in AGS. Central administration of MK‐801 (0.2, 2, 20 or 200 μg; icv) to hibernating AGS failed to induce arousal. Results suggest that activation of NMDAR at a peripheral or circumventricular site is necessary to maintain prolonged torpor and that a decrease in glutamate at these sites may contribute to spontaneous arousal in AGS.
Spatial and spatial‐frequency analysis in visual optics
Authors: Westheimer Gerald
Published: June 2012

Citation information: Westheimer G. Spatial and spatial‐frequency analysis in visual optics. Ophthalmic Physiol Opt 2012, 32, 271–281. doi: 10.1111/j.1475‐1313.2012.00913.x

Background:  In the specification of visual targets and their transmission through the eye’s optics to form retinal images, the spatial distribution of energy and its Fourier transform, the spatial‐frequency spectrum, are equivalent, so long as linearity constraints are obeyed. The power spectrum, in which phase has been discarded, is an insufficient descriptor; it does not enable the original object to be reconstituted.

Procedure:  Not so well known, and explored here, are joint representations in the space and spatial‐frequency dimensions. Their properties are outlined for some sample targets and for transforms of the Gabor, Difference‐of‐Gaussians and Wigner types. A related approach is one in which other kernel functions, such as the Gaussian or its derivative, are substituted for the cosines in the Fourier transform; here also graphs can be generated which jointly display properties both of the target and of its point‐by‐point representation in a size‐tuned domain.

Applications:  This kind of study has application in matching the performance characteristics of optical devices to the eye’s, in optical superresolution, and in the analysis of the demands placed on neural processing in, for example, visual hyperacuity.
Parallactic movement beats binocularity in the presence of external visual noise
Authors: Voges Nicole , Bach Michael , Kommerell Guntram
Published: June 2012

Citation information: Voges N, Bach M & Kommerell G. Parallactic movement beats binocularity in the presence of external visual noise. Ophthalmic Physiol Opt 2012, 32, 308–316. doi: 10.1111/j.1475‐1313.2012.00917.x

Purpose:  Binocular vision provides a considerable advantage over monocular vision when stationary particles partly obstruct the view. Such situations occur in real life, e.g., when drivers are trying to identify objects through a windshield dotted with snowflakes. In the process of driving, any bumpiness of the road will bring about a parallactic movement of particles on the windshield with respect to the visual object. We investigated whether this parallactic movement diminishes the advantage of binocular over monocular vision.

Methods:  Using computer graphics, we simulated a driving situation with snowflakes represented by noise particles on the windshield. Ten observers tried to identify a Landolt ring (8 possible orintations, gap always 2.5 arcmin) presented for 2 s at a viewing distance of 2 m. The partly obstructing noise particles, either stationary or moving vertically at three sinusoidal velocities, were presented at a viewing distance of 0.8 m, corresponding to a stereodisparity well beyond Panum’s fusional area. We compared the percentage of correct responses and the reaction time between binocular and monocular vision.

Results:  When the ‘snowflakes’ were stationary, binocular vision yielded more correct responses than monocular vision (52.2 ± 1.8% vs 39.7 ± 1.7%). When the ‘snowflakes’ were moving, the task was much easier and the binocular advantage less pronounced (95.8 ± 1.4% vs 85.3 ± 5.2%). The reaction time with stationary noise was 1.25 s for binocular and 1.31 s for monocular vision. With moving noise, averaged over all three velocities, the reaction time was 1.23 s for binocular and 1.36 s for monocular vision.

Conclusion:  Parallactic movement of partly obstructing particles reduces the advantage of binocular over monocular vision to practically irrelevant values.
Effects of error in radius of curvature on the corneal power measurement before and after laser refractive surgery for myopia
Authors: Liu Yongji , Wang Yan , Wang Zhaoqi , Zuo Tong
Published: June 2012

Citation information: Liu Y, Wang Y, Wang Z & Zuo T. Effects of error in radius of curvature on the corneal power measurement before and after laser refractive surgery for myopia. Ophthalmic Physiol Opt 2012, 32, 355–361. doi: 10.1111/j.1475‐1313.2012.00921.x

Purpose:  To investigate the sources of error in corneal power measurement before and after corneal refractive surgery for myopia.

Methods:  The study comprised 28 eyes of six males and eight females with a mean age of 26 (range 18–39 years). The radius of curvature of anterior and posterior corneal surface, Q‐Values of anterior and posterior corneal surface and corneal central thickness were measured by rotating Scheimpflug imaging (Pentacam). The true net power Fg, back vertex power Fv, and keratometric power SimK, were calculated respectively at the apex and at a paracentral area on the 3 mm ring.

Results:  For virgin eyes, the overestimation (0.53 ± 0.11 D) of the corneal power by using a keratometric index of 1.3375 was balanced by the underestimation (−0.21 ± 0.09 D) of the corneal power by the error in the radius of curvature, resulting in a relatively small corneal power error with a mean value of 0.33 ± 0.11 D. With the Q‐value changing from −0.09 to −0.41, the percentage balanced by the error in radius of curvature increased from 16% to 73%. However, for eyes after laser refractive surgery, the radius of curvature error lead to an overestimation (0.54 ± 0.16 D) of the corneal power and the keratometric index of 1.3375 again overestimated (1.59 ± 0.26 D) the corneal power, resulting in a large measurement error with a mean value of 2.12 ± 0.40 D. With the Q‐value changing from 0.35 to 1.89, the percentage added by the error in radius of curvature increased from 14% to 32%.

Conclusions:  For virgin eyes, the overestimation of the corneal power by using a keratometric index of 1.3375 is balanced by the underestimation of the corneal power by the error in the radius of curvature, resulting in a relatively small corneal power error. However, for eyes after laser refractive surgery, the flatter anterior corneal surface means that the use of a keratometric index of 1.3375 significantly overestimates the corneal power and the radius of curvature error now adds to this overestimation and results in a large measurement error.
Price Levels and Economic Growth: Making Sense of Revisions to Data on Real Incomes
Authors: Ravallion Martin
Published: June 2012

The price surveys from the 2005 International Comparison Program (ICP) imply substantially lower levels of GDP at purchasing power parity (PPP) for many developing countries than prior estimates. While some observers have questioned the data, this paper argues that the pattern of changes in PPPs between ICP rounds makes economic sense. Consistently with the original Balassa–Samuelson model, more rapidly growing economies experienced steeper increases in their PPPs relative to official exchange rates. This effect was even stronger for poor countries. Taking account of this effect would reduce the need for such large data revisions when new ICP data become available.
A Generalized Exactly Additive Decomposition of Aggregate Labor Productivity Growth
Authors: Dumagan Jesus C.
Published: June 2012

Aggregate labor productivity (ALP) growth—i.e., growth of output per unit of labor—may be decomposed into additive contributions due to within‐sector productivity growth effect, dynamic structural reallocation effect (Baumol effect), and static structural reallocation effect (Denison effect) of cross‐sectional components (e.g., industry or region) of output and labor. This paper implements ALP growth decomposition that is “generalized” to output in constant prices and to output in chained prices (i.e., chained volume measure or CVM) and “exactly additive” since with either output the sum of contributions exactly equals “actual” ALP growth. It compares this “generalized exactly additive” decomposition (GEAD) to the “traditional” (TRAD) ALP growth decomposition devised for output in constant prices. The results show GEAD and TRAD are exactly additive when output is in constant prices, but GEAD is exactly additive while TRAD is not when output is in CVM. Also, GEAD components are empirically purer than or analytically superior to those from TRAD. Moreover, considering that contributions to ALP growth can be classified by industry or region each year over many years, GEAD provides a more well‐grounded picture over time of industrial or regional transformation than TRAD. Therefore, GEAD should replace TRAD in practice.
Treatment of infertility with hypogonadotropic hypogonadism: 10‐year experience in Auckland, New Zealand
Authors: Milsom Stella , Duggan Kate , O'sullivan Susannah , Ogilvie Megan , Gunn Alistair Jan
Published: June 2012

Infertility in idiopathic or acquired hypogonadotropic hypogonadism (HH) was managed with exogenous gonadotropins and artificial reproduction as needed, in Auckland, New Zealand, from 2000 to 2010. Of eight men seeking conception, 2/2 with acquired HH but only 2/6 with congenital HH achieved clinical pregnancy with exogenous gonadotropins, whereas 12/14 women (86%) achieved one or more live births. Current gonadotropin treatment does not seem to be optimal for men with congenital HH.
Determining Prevalence and Correlates of Elder Abuse Using Promotores: Low‐Income Immigrant Latinos Report High Rates of Abuse and Neglect
Authors: DeLiema Marguerite , Gassoumis Zachary D. , Homeier Diana C. , Wilber Kathleen H.
Published: June 2012

Low‐income Latino immigrants are understudied in elder abuse research. Limited English proficiency, economic insecurity, neighborhood seclusion, a tradition of resolving conflicts within the family, and mistrust of authorities may impede survey research and suppress abuse reporting. To overcome these barriers, promotores, local Spanish‐speaking Latinos, were recruited and trained to interview a sample of Latino adults aged 66 and older residing in low‐income communities. The promotores conducted door‐to‐door interviews in randomly selected census tracts in Los Angeles to assess the frequency of psychological, physical, and sexual abuse; financial exploitation; and caregiver neglect. Overall, 40.4% of elderly Latino adults had experienced some form of abuse or neglect within the previous year. Nearly 25% reported psychological abuse, 10.7% physical assault, 9% sexual abuse, and 16.7% financial exploitation, and 11.7% were neglected by their caregivers. Younger age, higher education, and experiencing sexual or physical abuse before age 65 were significant risk factors for psychological, physical, and sexual abuse. Years lived in the United States, younger age, and prior abuse were associated with greater risk of financial exploitation. Years spent living in the United States was a significant risk factor for caregiver neglect. Abuse prevalence was much higher in all mistreatment domains than findings from previous research on community‐dwelling elderly adults, suggesting that low‐income Latino immigrants are highly vulnerable to elder mistreatment or that respondents are more willing to disclose abuse to promotores who represent their culture and community.
Unsmoothing Real Estate Returns: A Regime‐Switching Approach
Authors: Lizieri Colin , Satchell Stephen , Wongwachara Warapong
Published: June 2012

We propose newly developed unsmoothing techniques for appraisal‐based real estate returns based on a regime‐switching threshold autoregressive (TAR) model. We show that when true returns follow a TAR process, conventional linear autoregressive techniques are misspecified and underestimate true variance. Two exogenous variables, equity returns and gross domestic product growth, outperform other variables as regime indicators and appear to capture risks of downturns in real estate. We extend the model to the smoothing equation, allowing for switching behavior by appraisers, using two new techniques: the TAR‐AR and TAR‐TAR approaches. The “co‐switching” specification opens up a new frontier of empirical research. We estimate the TAR‐TAR using FT returns as the regime indicator, and we find results that outperform conventional smoothing models and have plausible economic explanations.
Financing Residential Development with Special Districts
Authors: Billings Stephen B. , Thibodeau Thomas G.
Published: June 2012

This paper empirically examines the extent to which the property tax liability created by financing residential infrastructure using special district bonds is capitalized in house prices. We compare house prices for single‐family detached homes built within development districts to similar properties located outside development districts. Our hedonic specification includes the usual housing characteristics and controls for the influence of spatial attributes using Census Block Group “neighborhood” fixed effects. The preferred empirical specification restricts the data to neighborhoods that have numerous sales of recently constructed single‐family detached homes located both within and outside development districts. The empirical results indicate that house prices for homes located within development districts are lower than house prices for similar homes located outside of development districts, but the amount of property tax capitalization is significantly less than full. Results depend on our Generalized Methods of Moments estimator, which instruments property tax rates using the characteristics of development districts. We identify valid instruments by restricting transactions to properties located in rapidly growing suburban developments.
Does host adaptation of Tetranychus urticae populations in clementine orchards with a Festuca arundinacea cover contribute to a better natural regulation of this pest mite?
Authors: Aguilar‐Fenollosa Ernestina , Pina Tatiana , Gómez‐Martínez María A. , Hurtado Mónica A. , Jacas Josep A.
Published: June 2012

Tetranychus urticae Koch (Acari: Tetranychidae) is a key pest of clementine mandarins, Citrus clementina Tanaka (Rutaceae), in Spain. This mite is highly polyphagous and can be easily found in clementine orchards, both in the trees and in the associated flora. In a previous study we found that the use of a cover of Festuca arundinacea Schreber (Poaceae) offered a better regulation of T. urticae populations than either bare soil or the traditional wild cover, which included a mix of weed species. We hypothesized that the selection of two host races of T. urticae, specialized in F. arundinacea and C. clementina, could partly explain the results obtained (bottom‐up regulation). Reciprocal transplant experiments show that sympatric deme × host combinations had higher mean fitness values than the allopatric combinations in clementine, but not in F. arundinacea, for most of the fitness parameters evaluated in our study. Because local adaptation implies mean deme fitness to be systematically higher for the sympatric deme × habitat combinations than for the allopatric ones, these results can be taken as indicative of occurrence of local adaptation in T. urticae. Molecular genetic analyses with microsatellite markers support this conclusion and indicate that local adaptation of T. urticae found in our system may indeed contribute to a better natural regulation of this mite.
Transendocardial cell injection is not superior to intracoronary infusion in a porcine model of ischaemic cardiomyopathy: a study on delivery efficiency
Authors: van der Spoel Tycho I.G. , Vrijsen Krijn R. , Koudstaal Stefan , Sluijter Joost P.G. , Nijsen Johannes Frank W. , de Jong Hugo W. , Hoefer Imo E. , Cramer Maarten‐Jan M. , Doevendans Pieter A. , van Belle Eric , Chamuleau Steven A.J.
Published: June 2012

Stem cell therapy is a new strategy for chronic ischaemic heart disease in patients. However, no consensus exists on the most optimal delivery strategy. This randomized study was designed to assess cell delivery efficiency of three clinically relevant strategies: intracoronary (IC) and transendocardial (TE) using electromechanical mapping guidance (NOGA) compared to surgical delivery in a chronic pig model of ischaemic cardiomyopathy. Twenty‐four animals underwent delivery of 107 autologous Indium‐oxine‐labelled bone marrow‐derived mesenchymal stem cells (MSC) 4 weeks after infarction and were randomized to one of three groups (n = 8 each group): IC, TE or surgical delivery (reference group). Primary endpoint was defined as percentage (%) of injected dose per organ and assessed by in vivo gamma‐emission counting. In addition, troponin and coronary flow were assessed before and after MSC injection. Blinded endpoint analysis showed no significant difference in efficiency after surgical (16 ± 4%), IC (11 ± 1%) and TE (11 ± 3%) (P = 0.52) injections. IC showed less variability in efficiency compared with TE and surgical injection. Overall, TE injection showed less distribution of MSC to visceral organs compared with other modalities. Troponin rise and IC flow did not differ between the percutaneous groups. This randomized study showed no significant difference in cell delivery efficiency to the myocardium in a clinically relevant ischaemic large animal model between IC and TE delivery. In addition, no differences in safety profile were observed. These results are important in view of the choice of percutaneous cell delivery modality in future clinical stem cell trials.
Predictors of inter‐proximal and midfacial recession following single implant treatment in the anterior maxilla: a multivariate analysis
Authors: Cosyn Jan , Sabzevar Mehran M. , De Bruyn Hugo
Published: June 2012

Purpose

A number of factors have been associated with soft tissue recession following single implant treatment. However, given the cross‐sectional design of most of these studies and crude associations based on univariate analyses, such factors may only be considered risk indicators. The objective of the present retrospective cohort study using multivariate analyses was to identify predictors of recession.

Material and Methods

Patients who had been treated by two periodontists and two prosthodontists in 2006 and 2007 for a single implant in the anterior maxilla were re‐examined in 2009 and their records were scrutinized. Subjects treated via flap surgery with and without ridge re‐contouring were considered. Outcome variables were inter‐proximal and midfacial recession. Explanatory variables included demographic data, the surgical approach and a number of local factors that were evaluated on radiographs taken pre‐operatively or at permanent crown installation (baseline).

Results

Data pertaining to 97/115 (60 females, 37 males; mean age 51, SD 13, range 23–80) patients were available for evaluation. Significant bone loss was observed between baseline and re‐examination at the implant surface (0.2–0.3 mm, p < 0.001) and tooth surface (0.3–0.5 mm, p < 0.001). Surgery with ridge re‐contouring demonstrated 0.2 mm additional bone loss at the distal tooth surface when compared to surgery without ridge re‐contouring (p = 0.034). This could be explained by a disparity in possible papilla‐opening procedures (three versus one or two). As a result, regression analyses identified surgery with ridge re‐contouring as a predictor of inter‐proximal recession (OR ≥ 3.4). Pre‐operative bone level at the tooth surface was another predictor of inter‐proximal recession (OR ≥ 2.1). Recession of the distal papilla was also affected by a missing contact point (OR = 221.9), the implant‐to‐tooth distance (OR = 0.3) and the distance of the bone peak to the contact point (OR = 2.9). Midfacial recession was only associated with a buccal shoulder position (OR = 17.2).

Conclusions

To optimize soft tissue levels around single implants, clinicians should limit papilla‐opening procedures and pay utmost attention to a correct implant and contact point positioning.
C‐type natriuretic peptide slows down wound healing but promotes angiogenesis in SKH1‐hr hairless mice
Authors: Kuehnl Andreas , Pelisek Jaroslav , Ring André , Brzosko Barbara , Spindler Nick , Hatz Rudolf , Jauch Karl‐Walter , Eckstein Hans‐Henning , Langer Stefan
Published: June 2012

C‐type natriuretic peptide (CNP) is known to increase growth rate of endothelial cells in vitro. In addition, gene transfer of CNP into ischaemic muscle was shown to induce angiogenesis. So far, no study has addressed the effect of CNP on dermal wound healing. The ear wound model in mice was used in this study. The first group was treated with dsRed‐CNP plasmid, whereas the second group was transfected with the empty dsRed‐sine plasmid, lacking sequence coding for CNP. The third group was sham operated and treated with saline to serve as second control. Wound size was measured on days 0, 1, 3, 5, 7, 9, 11 and 14. On days 7 and 14 capillary density was analysed. Wound closure rate was significantly reduced in mice treated with CNP [dsRed‐CNP 73·3 ± 3·2% versus dsRed‐sine 94·5 ± 2·4% versus saline 92·1 ± 2·4%, n = 8 per group, analysis of variance (ANOVA) P < 0·001] at day 7 postop. Capillary density was found to be significantly higher in CNP‐treated mice (dsRed‐CNP 18·7 ± 3·9 versus dsRed‐sine 12·3 ± 2·7 versus control 10·1 ± 4·7, CD31+ capillaries per microscope field, ANOVA P = 0·018) at day 14 postoperative. CNP significantly reduces wound closure rate in hairless mice but promotes the development of new blood vessels. A possible explanation is the dual effect of CNP, inhibiting growth of fibromyoblasts but stimulating growth of endothelial cells. Thus, CNP may serve as a therapeutic approach to diseases caused by hyperfibrosis.
Improvisations in classic and modified techniques of flap surgery to improve the success rate for pressure ulcer healing in patients with spinal cord injury
Authors: Singh Roop , Singh Raghubir , Rohilla Rajesh K , Magu Narender K , Goel Rakesh , Kaur Kiranpreet
Published: June 2012

The recurrence of pressure ulcers (PrUs) and dehiscence of reconstructive flap have always been a problem. The present study aimed to evaluate the results of reconstructive flap surgeries in patients with spinal cord injury (SCI) having PrUs, using classic and modified flaps with improvisations to decrease wound dehiscence, flap necrosis and tension in flap. This is a prospective clinical study. The setting was a tertiary care centre in northern India. Thirty‐five patients with SCI having 37 stage III and IV PrUs. PrUs were treated using classic and modified flaps with improvisations. The outcome was evaluated using criteria of wound dehiscence, flap necrosis and recurrence. The results of flap surgery were excellent in 32 (86·48%) patients, good in 4 (10·81%) patients and poor in 1 (2·7%) patient. Partial flap necrosis (2·7%), low incidence of PrU recurrence rate at flap site (5·4%) and overall PrU recurrence (11·4%) were the complications observed. Improvisation of classic and modified techniques of flap surgeries along with reinforcement of general care principles of paraplegia can be effective in minimising complications often associated with PrU reconstructive surgery thus improving the ultimate outcome.
Necrotising fasciitis in the central part of the body: diagnosis, management and review of the literature
Authors: Vayvada Haluk , Demirdover Cenk , Menderes Adnan , Karaca Can
Published: June 2012

Necrotising fasciitis (NF) is characterised by rapidly spreading necrosis of the soft tissue and fascia. It is rare but can be fatal when not managed properly. The aim of this study is to evaluate the diagnosis, treatment and results such as mortality, morbidity and reconstructive options of NF localised in the central part of the body. The main goal is to emphasise upon the clinical symptoms for early diagnosis which is the most important factor in saving the lives of these patients. Between January 2000 and December 2010, 30 patients with NF localised in central parts of the body were treated. Six of the patients were female (20%) and the others were male (80%). The mean age was 54·03 years (ranged between 26 and 83 years). The average time from the onset of symptoms to diagnosis was 6 days, ranging from 2 to 11 days. The localisation of NF was perineum in 24 patients (80%); inguinal and thigh region in 5 patients (16·7); and back in 1 patient (3·3%). The hospitalisation time was varying between 17 and 32 days (mean 23 days). Six patients (20%) died and 24 patients (80%) survived. All non‐survivors had risk factors and secondary comorbidities such as immunosuppression, chronic cardiac failure, and diabetes with high glucose level. Survivors also underwent repeated debridement operation 2–4 times. Reconstructive procedures were split‐thickness skin graft (STSG) in eight patients (33·3%), fasciocutaneous flaps in four patients (16·6%), fasciocutaneous flap + STSG in six patients (25%), scrotal flap + STSG in two patients (6·6%), scrotal flap in two patients (6·6%) and musculocutaneous flap + STSG in one patient (3·3%). There was no major complication such as flap and graft loss, after reconstructive procedures. Early diagnosis of NF may be the lifesaving factor. Amuputation can save the patient's life in the case of NF in the extremities; however, this is not an option for NF in central parts of the body. In these cases, when NF is suspected, early debridement of necrotic tissues should be performed. As soon as the infection and the spread of the necrosis are controlled, reconstruction should be considered.
The Ca2+‐dependent DNases are Involved in Secondary Xylem Development in Eucommia ulmoides
Authors: Chen Hui‐Min , Pang Yu , Zeng Jun , Ding Qi , Yin Shen‐Yi , Liu Chao , Lu Meng‐Zhu , Cui Ke‐Ming , He Xin‐Qiang
Published: June 2012

Secondary xylem development has long been recognized as a typical case of programmed cell death (PCD) in plants. During PCD, the degradation of genomic DNA is catalyzed by endonucleases. However, to date, no endonuclease has been shown to participate in secondary xylem development. Two novel Ca2+‐dependent DNase genes, EuCaN1 and EuCaN2, were identified from the differentiating secondary xylem of the tree Eucommia ulmoides Oliv., their functions were studied by DNase activity assay, in situ hybridization, protein immunolocalization and virus‐induced gene silencing experiments. Full‐length cDNAs of EuCaN1 and EuCaN2 contained an open reading frame of 987 bp, encoding two proteins of 328 amino acids with SNase‐like functional domains. The genomic DNA sequence for EuCaN1 had no introns, while EuCaN2 had 8 introns. EuCaN1 and EuCaN2 digested ssDNA and dsDNA with Ca2+‐dependence at neutral pH. Their expression was confined to differentiating secondary xylem cells and the proteins were localized in the nucleus. Their activity dynamics was closely correlated with secondary xylem development. Secondary xylem cell differentiation is influenced by RNAi of endonuclease genes. The results provide evidence that the Ca2+‐dependent DNases are involved in secondary xylem development.
Diversification in Indian Agriculture toward High‐Value Crops: The Role of Small Farmers
Authors: Birthal Pratap Singh , Joshi Pramod Kumar , Roy Devesh , Thorat Amit
Published: June 2012

Diversification by small farmers toward high‐value crops (fruits and vegetables [F & V]) that can raise farm incomes significantly has always been in question because of several reasons such as diseconomies of scale and lack of access to inputs such as capital and information. We present evidence that in India diversification toward high‐value crops exhibits a pro‐smallholder (rather than anti‐smallholder) bias. The smallholders however play a proportionally larger role in vegetables than in fruits cultivation. These patterns are consistent with simple comparative advantage‐based production choices. Even with small landholdings if labor endowments are high, such farmers diversify toward F & V. Though fruits cultivation is also labor intensive relative to cereals, it is less so relative to vegetables. Greater capital intensity implies a comparatively important role of credit in fruits. The results are robust to several tests on specification including those related to self‐selection.

Chez les petits exploitants agricoles, la diversification en faveur de cultures à valeur élevée (fruits et légumes) permettant d’accroître considérablement le revenu agricole a toujours été remise en question pour diverses raisons, notamment les déséconomies d’échelle et le manque d’accès aux intrants comme le capital et l’information. Dans le présent article, nous montrons qu’en Inde, la diversification en faveur de cultures à valeur élevée semble plutôt favorable que défavorable aux petits exploitants agricoles. Toutefois, les petits exploitants sont proportionnellement plus présents dans la culture maraîchère que dans la culture fruitière. Ces observations concordent avec les choix d’une production fondée sur les avantages comparatifs. Même dans le cas des petites exploitations, lorsque les besoins de main‐d’œuvre sont élevés, elles se tournent vers les cultures fruitière et maraîchère. Bien que la culture fruitière soit une activitéà forte intensité de main‐d’œuvre comparativement à la culture céréalière, elle l’est moins que la culture maraîchère. L’intensité de capital élevée de la culture fruitière signifie que le crédit joue aussi un rôle important. Les résultats de plusieurs tests de spécification sont robustes, y compris ceux liés à l’auto‐sélection.