bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fund management and its effect in the Greek social security system
Authors: MILONAS NIKOLAOS T. , PAPACHRISTOU GEORGE A. , ROUPAS THEODORE A. 
Published: November 2007

AbstractEconomic and demographic slowdown has put under strain public pension systems around the globe. In this paper, we discuss the characteristics of the Greek social security system and investigate the issue of pension fund management. Our empirical analysis focuses on whether flexible investment rules (including equity investment) could have taken the pressure off the Greek public pension system while reducing the risks associated with such flexibility. The empirical results of the paper suggest that efficient management of reserves can result in additional significant revenues at acceptable levels of financial risk. However, pension fund management flexibility cannot by itself resolve the problem of social security system.
An empirical analysis of the annuity rate in Chile
Authors: ROCHA ROBERTO , MORALES MARCO , THORBURN CRAIG 
Published: November 2007

SUMMARYEmpirical analyses of annuities markets have been limited to a few developed countries and restricted by data limitations. Chile provides excellent conditions for research on annuities due to the depth of its market and the availability of data. The paper utilizes a panel of life insurance company data to examine econometrically the main determinants of the annuity rate, defined as the internal rate of return on annuities. The results indicate that the annuity rate is determined by the risk-free interest rate, the share of privately issued higher yield securities in the portfolio of providers, as a proxy for the spread over the risk-free rate, the leverage of providers, the level of broker's commissions, the market share of individual providers, the level of the premium, and the degree of market competition. The results also show that efforts to improve market transparency produced structural shifts in the parameters of the annuity rate equation. The results are consistent with separate research on money's worth ratios, and indicate the need to develop appropriate financial instruments, allowing providers to hedge their risks while extracting higher returns, and also to ensure competition and transparency in annuities markets, in order to ensure good outcomes for annuitants.
Earnings management, expected returns on pension assets, and resource allocation decisions
Authors: ASTHANA SHARAD 
Published: November 2007

AbstractThis paper empirically examines the role of expected rate of return on pension assets reported under SFAS 87 as a tool for meeting and beating earnings targets and its effect on firm value. Results suggest that managers may use this pension assumption to inflate earnings per share (eps) when they are going to miss the earnings expectations. The earnings inflation is directly related to the amount by which earnings will miss the target and to earning sensitivity to expected return on pension asset assumption. The results are robust to two different measures of earnings inflation and two of earnings expectations.The market behaves semi-efficiently and appears to adjust the firm value for large earnings inflations and in situations where firms have incentives to manipulate earnings or earnings are highly sensitive to expected rate of return on pension assets. However, this adjustment is not complete and post-announcement returns continue to depend on the inflated component of earnings, confirming that resource allocation decisions are based on managed earnings. Additional disclosure requirements to make pension assumptions more transparent are also discussed in the paper. Such disclosures could enhance the efficient use of the information by market participants.
On the financial sustainability of earnings-related pension schemes with ‘pay-as-you-go’ financing and the role of government-indexed bonds
Authors: ROBALINO DAVID A. , BODOR ANDRÁS 
Published: November 2007

AbstractIn this paper we reconsider the idea of an earnings-related pension system with reserves invested in indexed government bonds as a mechanism to both ensure financial sustainability and improve security. The paper starts by reviewing the characterization of the sustainable rate of return of an earnings-related pension system with pay-as-you-go financing. We show that current proxies for the sustainable rate, including the Swedish ‘gyroscope’, are not stable and propose an alternative measure that depends on the growth of the buffer-stock and the pay-as-you-go asset. Using a simple one-sector macroeconomic model that embeds a notional account pension system we then show how GDP-indexed government bonds, if combined with the right measure for the sustainable rate of return on contributions, could be used to generate a sustainable and secure earnings-related pension system, without becoming a fiscal burden. The proposal is particularly attractive for countries considering reforms to earnings-related systems that have accumulated a large implicit pension debt. In this case, the government bonds allow the financing of this debt in a transparent way. The proposed mechanism can also facilitate the transition to a fully funded pension system when the government bonds are allowed to be traded.
The Synergistic Action of a VEGF‐Receptor Tyrosine‐Kinase Inhibitor and a Sensitizing PDGF‐Receptor Blocker Depends upon the Stage of Vascular Maturation
Authors: Hlushchuk Ruslan , Baum Oliver , Gruber Guenther , Wood Jeanette , Djonov Valentin 
Published: November 2007

ABSTRACTObjective: To investigate the effects of tyrosine‐kinase inhibitors of vascular endothelial growth factor (VEGF) and platelet‐derived growth factor (PDGF)‐receptors on non‐malignant tissue and whether they depend upon the stage of vascular maturation.Materials and methods: PTK787/ZK222584 and CGP53716 (VEGF‐ and PDGF‐receptor inhibitor respectively), both alone and combined, were applied on chicken chorioallantoic membrane (CAM).Results: On embryonic day of CAM development (E)8, only immature microvessels, which lack coverage of pericytes, are present; whereas the microvessels on E12 have pericytic coverage. This development was reflected in the expression levels of pericytic markers (α ‐smooth muscle actin, PDGF‐receptor ß and desmin), which were found by immunoblotting to progressively increase between E8 and E12. Monotherapy with 2 μ g of PTK787/ZK222584 induced significant vasodegeneration on E8, but not on E12. Monotherapy with CGP53716 affected only pericytes. When CGP53716 was applied prior to treatment with 2 μ g of PTK787/ZK222584, vasodegeneration occurred also on E12. The combined treatment increased the apoptotic rate, as evidenced by the cDNA levels of caspase‐9 and the TUNEL‐assay.Conclusion: Anti‐angiogenic treatment strategies for non‐neoplastic disorders should aim to interfere with the maturation stage of the target vessels: monotherapy with VEGF‐receptor inhibitor for immature vessels, and combined anti‐angiogenic treatment for well developed mature vasculature.
Novel Technique for Estimating Cerebrovascular Permeability Demonstrates Capsazepine Protection Following Ischemia‐Reperfusion
Authors: Gauden Victoria , Hu D.‐E. , Kurokawa T. , Sarker M. H. , Fraser P. A. 
Published: November 2007

ABSTRACTObjective: There has been some discussion as to whether the pial vasculature behaves in the same way as the blood‐brain barrier as a whole. Recent studies have shown that capsazepine protects these vessels from the effects of ischemia‐reperfusion. We have now used a new method to examine this protection in the whole brain.Methods: Horseradish peroxidase concentrations were measured in brain sections and plasma, following starch microsphere induced ischemia, which lasted from 20 to 60 minutes, with 30 minutes reperfusion. The PS product was calculated from the Crone‐Renkin equation.Results: Permeability increase, which depended on duration of ischemia, was considerably greater in the pia than the parenchyma. The increase was also greater in tissue surrounding large radial venules of the cortex. Single vessel studies showed that these differences mirror those between small and large pial venules. Capsazepine treatment protected the parenchymal blood‐brain barrier by limiting the post‐ischemic permeability increase to about one third, but had no effect on the pia or radial vessel permeability.Conclusions: Permeability has been estimated in tissue sections with good spatial resolution using this new technique, which has demonstrated that the TRPV1 receptor plays an important role in the whole brain, not confined to small pial venules.
Age‐Related Alterations of Active Pumping Mechanisms in Rat Thoracic Duct
Authors: Gasheva Olga Y. , Knippa Kevin , Nepiushchikh Zhanna V. , Muthuchamy Mariappan , Gashev Anatoliy A. 
Published: November 2007

ABSTRACTObjective: To evaluate the age‐related changes in active pumping in thoracic duct (TD) from 24‐month‐old Fisher‐344 rats comparing with TD pumping in 9‐month rats.Methods: Lymphatic diameters, contraction amplitude and frequency, ejection fraction, and fractional pump flow were determined in isolated TD preparations. Western blot analyses were performed to evaluate relative levels of eNOS and iNOS in 9‐ and 24‐month‐old TD.Results: Stretch‐dependent regulation was altered in aged TD especially at higher levels of pressure: the negative inotropy, negative chronotropy and diminished minute pumping (2‐ to 3‐fold decrease) were observed. Physiological NO/imposed‐flow‐dependent inhibition was completely abolished in aged TD, yet NO‐synthase blockade by l‐NAME (10−4 M) increased pumping in a flow‐independent manner. Western blot analyses indicated that the relative levels of eNOS were decreased ∼ 7‐fold in the 24‐month‐old TD when compared with 9‐month‐old TD; whereas iNOS levels were increased ∼ 10‐fold in 24‐month‐old TD.Conclusions: These data provide the first evidence that stretch‐ and imposed‐flow‐dependent regulatory mechanisms are greatly altered in aged TD. These alterations of active pumping mechanisms in TD appear to be related with age‐related disturbances in NO‐dependent regulatory pathways, and may reflect diminished lymphatic muscle contractility as well as altered lymphatic endothelium function.
Low folding propensity and high translation efficiency distinguishin vivosubstrates of GroEL from otherEscherichia coliproteins
Authors: Noivirt-Brik Orly , Unger Ron , Horovitz Amnon 
Published: November 2007

AbstractMotivation: Theoretical considerations have indicated that the amount of chaperonin GroEL in Escherichia coli cells is sufficient to fold only ∼2–5% of newly synthesized proteins under normal physiological conditions, thereby suggesting that only a subset of E.coli proteins fold in vivo in a GroEL-dependent manner. Recently, members of this subset were identified in two independent studies that resulted in two partially overlapping lists of GroEL-interacting proteins. The objective of the work described here was to identify sequence-based features of GroEL-interacting proteins that distinguish them from other E.coli proteins and that may account for their dependence on the chaperonin system.Results: Our analysis shows that GroEL-interacting proteins have, on average, low folding propensities and high translation efficiencies. These two properties in combination can increase the risk of aggregation of these proteins and, thus, cause their folding to be chaperonin-dependent. Strikingly, we find that these properties are absent in proteins homologous to the E.coli GroEL-interacting proteins in Ureaplasma urealyticum, an organism that lacks a chaperonin system, thereby confirming our conclusions.Contact: amnon.horovitz@weizmann.ac.ilSupplementary information: Supplementary data are available at Bioinformatics online.
Detecting high-order interactions of single nucleotide polymorphisms using genetic programming
Authors: Nunkesser Robin , Bernholt Thorsten , Schwender Holger , Ickstadt Katja , Wegener Ingo 
Published: November 2007

AbstractMotivation: Not individual single nucleotide polymorphisms (SNPs), but high-order interactions of SNPs are assumed to be responsible for complex diseases such as cancer. Therefore, one of the major goals of genetic association studies concerned with such genotype data is the identification of these high-order interactions. This search is additionally impeded by the fact that these interactions often are only explanatory for a relatively small subgroup of patients. Most of the feature selection methods proposed in the literature, unfortunately, fail at this task, since they can either only identify individual variables or interactions of a low order, or try to find rules that are explanatory for a high percentage of the observations. In this article, we present a procedure based on genetic programming and multi-valued logic that enables the identification of high-order interactions of categorical variables such as SNPs. This method called GPAS cannot only be used for feature selection, but can also be employed for discrimination.Results: In an application to the genotype data from the GENICA study, an association study concerned with sporadic breast cancer, GPAS is able to identify high-order interactions of SNPs leading to a considerably increased breast cancer risk for different subsets of patients that are not found by other feature selection methods. As an application to a subset of the HapMap data shows, GPAS is not restricted to association studies comprising several 10 SNPs, but can also be employed to analyze whole-genome data.Availability: Software can be downloaded from http://ls2-www.cs.uni-dortmund.de/~nunkesser/#SoftwareContact: robin.nunkesser@uni-dortmund.de
TMBpro: secondary structure, β-contact and tertiary structure prediction of transmembrane β-barrel proteins
Authors: Randall Arlo , Cheng Jianlin , Sweredoski Michael , Baldi Pierre 
Published: November 2007

Abstract
Motivation: Transmembrane β-barrel (TMB) proteins are embedded in the outer membranes of mitochondria, Gram-negative bacteria and chloroplasts. These proteins perform critical functions, including active ion-transport and passive nutrient intake. Therefore, there is a need for accurate prediction of secondary and tertiary structure of TMB proteins. Traditional homology modeling methods, however, fail on most TMB proteins since very few non-homologous TMB structures have been determined. Yet, because TMB structures conform to specific construction rules that restrict the conformational space drastically, it should be possible for methods that do not depend on target-template homology to be applied successfully.
Results: We develop a suite (TMBpro) of specialized predictors for predicting secondary structure (TMBpro-SS), β-contacts (TMBpro-CON) and tertiary structure (TMBpro-3D) of transmembrane β-barrel proteins. We compare our results to the recent state-of-the-art predictors transFold and PRED-TMBB using their respective benchmark datasets, and leave-one-out cross-validation. Using the transFold dataset TMBpro predicts secondary structure with per-residue accuracy (Q2) of 77.8%, a correlation coefficient of 0.54, and TMBpro predicts β-contacts with precision of 0.65 and recall of 0.67. Using the PRED-TMBB dataset, TMBpro predicts secondary structure with Q2 of 88.3% and a correlation coefficient of 0.75. All of these performance results exceed previously published results by 4% or more. Working with the PRED-TMBB dataset, TMBpro predicts the tertiary structure of transmembrane segments with RMSD &lt;6.0 Å for 9 of 14 proteins. For 6 of 14 predictions, the RMSD is &lt;5.0 Å, with a GDT_TS score greater than 60.0.
Availability: http://www.igb.uci.edu/servers/psss.html
Contact: pfbaldi@ics.uci.edu
Supplementary information: Supplementary data are available at Bioinformatics online.
GWAsimulator: a rapid whole-genome simulation program
Authors: Li Chun , Li Mingyao 
Published: November 2007

Abstract
Summary: GWAsimulator implements a rapid moving-window algorithm to simulate genotype data for case-control or population samples from genomic SNP chips. For case-control data, the program generates cases and controls according to a user-specified multi-locus disease model, and can simulate specific regions if desired. The program uses phased genotype data as input and has the flexibility of simulating genotypes for different populations and different genomic SNP chips. When the HapMap phased data are used, the simulated data have similar local LD patterns as the HapMap data. As genome-wide association (GWA) studies become increasingly popular and new GWA data analysis methods are being developed, we anticipate that GWAsimulator will be an important tool for evaluating performance of new GWA analysis methods.
Availability: The C++ source code, executables for Linux, Windows and MacOS, manual, example data sets and analysis program are available at http://biostat.mc.vanderbilt.edu/GWAsimulator
Contact: chun.li@vanderbilt.edu
Supplementary information: Supplementary data are available at Bioinformatics online.
Sensitivity to Escherichia coli Nissle 1917 in mice is dependent on environment and genetic background
Authors: Bleich Andre , Sundberg John P. , Smoczek Anna , Von Wasielewski Reinhard , De Buhr Maike F. , Janus Lydia M. , Julga Gwen , Ukena Sya N. , Hedrich Hans‐J. , Gunzer Florian 
Published: November 2007

Summary Escherichia coli Nissle 1917 (EcN) is a well‐characterized probiotic bacterium. Although genomic comparisons of EcN with the uropathogenic E. coli strain CFT073 revealed high degrees of similarity, EcN is generally considered a non‐pathogenic organism. However, as recent evidence suggests that EcN is capable of inducing inflammatory responses in host intestinal epithelial cells, we aimed to investigate potential pathogenic properties of EcN in an in vivo model using various germ‐free (GF) mouse strains. With the exception of C3H/HeJZtm mice, which carry a defective toll‐like receptor (TLR)4‐allele, no lesions were obvious in mice of different strains orally inoculated with EcN for 1 week, although organ cultures (blood, lung, mesenteric lymph node, pancreas, spleen, liver and kidney) tested positive to various degrees. C3H/HeJZtm mice inoculated with EcN became clinically ill and the majority died or had to be euthanized. Organs of all gnotobiotic C3H/HeJZtm mice were positive for EcN by culture; major histological findings were moderate to severe pyogranulomatous serositis, typhlitis and pancreatitis. Histological findings were corroborated by highly elevated tumour necrosis factor (TNF) serum levels. Lesions were not detected in specified pathogen free maintained C3H/HeJZtm mice, GF C3H/HeJ mice lacking the interleukin‐10 gene, or GF C3H/HeJZtm mice that were inoculated with E. coli K12 strain MG1655 as a control. In addition, mild histological lesions were detected in Ztm:NMRI mice 3 months after oral inoculation with EcN. This study shows that EcN is capable of displaying a virulent phenotype in GF C3H/HeJZtm mice. Whether this phenotype is linked to the bacterium’s probiotic nature should be the focus of further studies.
Role of p38 mitogen‐activated protein kinase pathway on heart failure in the infant rat after burn injury
Authors: Kita Toshiro , Ogawa Midori , Sato Hiroaki , Kasai Kentaro , Tanaka Toshiko , Tanaka Noriyuki 
Published: November 2007

SummaryWe examined the hypothesis that post‐burn activation of the p38 mitogen‐activated protein kinase (MAPK) pathway is one aspect of the signalling cascade culminating in post‐burn secretion of tumour necrosis factor (TNF)‐α which contributes to post‐burn myocardial apoptosis. Studies were designed to determine the time course of the induction of p38MAPK, TNF‐α and myocardial apoptosis after burn injury. Our quantitative bacterial culture data demonstrated that viable bacteria reached the heart, and Western blotting data identified the increase in the phosphorylation of p38MAPK at an early time after burn. The peak incidence of myocardial apoptosis was also seen at an early time after burn. The expression of TNF‐α mRNA, infiltrated neutrophils and serum creatine phosphokinase myocardial band data peaked at a late time after burn. FR167653, a specific inhibitor of p38MAPK, prevented the induction of myocardial apoptosis, TNF‐α expression and myocardial injury after burn. Presumably, the bacterial LPS‐induced activation of p38MAPK pathway occurring at an early time after burn induced the subsequent myocardial apoptosis. The p38MAPK‐induced activation of pro‐inflammatory cytokine appeared to promote the degenerative myocardial injury at a late time after burn. Our present data provided evidence for the hypothesis that the p38MAPK pathway controls both myocardial apoptosis and the pro‐inflammatory mediator.
Effects of pasture management on the natural regeneration of neotropical trees
Authors: Esquivel M. Jimena , Harvey Celia A. , Finegan Bryan , Casanoves Fernando , Skarpe Christina 
Published: November 2007

Summary

Natural regeneration of forest trees in grazed pastures could potentially contribute to the conservation of tree diversity within the fragmented and agricultural landscapes that dominate much of the tropics. To understand this potential, we evaluated the effects of several widely used pasture management practices on tree regeneration in pastures in a tropical dry forest (subhumid) region of central Nicaragua.
Species richness, density, diversity and composition of seedlings, saplings and adult trees were compared in 46 pastures under different management conditions. The management conditions included three different types of grasses (Brachiaria spp., Cynodon spp. and naturalized pastures) and two categories of fire history (recently burnt and not recently burnt).
Thirty‐seven of the 85 tree species present in the pastures were regenerated under the current management conditions. The remaining 48 species may have had reduced natural regeneration because of limitations in either germination, dispersal, establishment or growth, as well as because of negative effects of pasture management practices.
The richness, density and species composition of tree seedlings within pastures were explained by grass species composition, the density and richness of adult trees, cattle management and the distance of the pasture to forest. In contrast, no clear effect of fire history was found.
Synthesis and applications. Current management practices allow the regeneration of almost half of the tree species in grazed pastures. However, to enhance the regeneration of species that show limited regeneration, management strategies, such as the retention of adult trees, protection of saplings and seedlings from weeding and grazing and use of enrichment plantings, may be necessary. These changes in pasture management would help contribute to the long‐term conservation of tree diversity within agricultural landscapes across the tropics.