bluuebunny/crossref_metadata_2025_split huggingface dataset:
Infantile and childhood onset PLA2G6‐associated neurodegeneration in a large North African cohort
Authors: Romani M. , Kraoua I. , Micalizzi A. , Klaa H. , Benrhouma H. , Drissi C. , Turki I. , Castellana S. , Mazza T. , Valente E. M. , Gouider‐Khouja N. 
Published: August 2014

Background and purposeMutations in the PLA2G6 gene are causative of PLA2G6‐associated neurodegeneration (PLAN), a spectrum of neurodegenerative conditions including infantile, childhood and adult onset forms.MethodsSeventeen North African patients with a clinical suspicion of infantile‐onset PLAN underwent clinical, neurophysiological and neuroimaging examinations, and PLA2G6 sequencing. Haplotype analysis was performed to date the identified founder mutation.ResultsAll patients carried biallelic mutations in PLA2G6. Sixteen children had the commonest form of infantile‐onset PLAN, with early onset of psychomotor regression, hypotonia, pyramidal and cerebellar signs, and abnormal ocular movements. The phenotype was highly homogeneous, with rapid development of severe spastic tetraparesis, cognitive impairment and optic atrophy. Neuroimaging showed cerebellar atrophy and claval hypertrophy to be the commonest and earliest signs, whilst cerebellar cortex hyperintensity and pallidal iron deposition were later findings. Motor or sensory‐motor neuropathy and electroencephalogram fast rhythms were also frequent. Nine patients from six families shared the same founder mutation (p.V691del) which probably arose by the late seventeenth century. Only one patient fitted the diagnosis of the much rarer childhood‐onset PLAN. Despite the early onset (18 months), clinical progression was slower, with behavioral disturbances and dystonia. Typical features of infantile‐onset PLAN such as hypotonia, nystagmus/strabismus, optic atrophy, electroencephalogram fast rhythms and motor neuropathy were absent. Cerebellar atrophy, claval hypertrophy and pallidal hypointensity were evident at brain magnetic resonance imaging. This patient carried a missense variant predicted to be less deleterious.ConclusionsThe PLAN‐associated phenotypes and the challenges of diagnosing the childhood‐onset form are delineated, and a common North African founder mutation is identifed.
The fitness costs of antibiotic resistance mutations
Authors: Melnyk Anita H. , Wong Alex , Kassen Rees 
Published: August 2014

AbstractAntibiotic resistance is increasing in pathogenic microbial populations and is thus a major threat to public health. The fate of a resistance mutation in pathogen populations is determined in part by its fitness. Mutations that suffer little or no fitness cost are more likely to persist in the absence of antibiotic treatment. In this review, we performed a meta‐analysis to investigate the fitness costs associated with single mutational events that confer resistance. Generally, these mutations were costly, although several drug classes and species of bacteria on average did not show a cost. Further investigations into the rate and fitness values of compensatory mutations that alleviate the costs of resistance will help us to better understand both the emergence and management of antibiotic resistance in clinical settings.
SPLUNC1 is associated with nasopharyngeal carcinoma prognosis and plays an important role in all‐trans‐retinoic acid‐induced growth inhibition and differentiation in nasopharyngeal cancer cells
Authors: Zhang Wenling , Zeng Zhaoyang , Wei Fang , Chen Pan , Schmitt David C. , Fan Songqing , Guo Xiaofang , Liang Fang , Shi Lei , Liu Zixin , Zhang Zuping , Xiang Bo , Zhou Ming , Huang Donghai , Tang Ke , Li Xiaoling , Xiong Wei , Tan Ming , Li Guiyuan , Li Xiayu 
Published: August 2014

Human SPLUNC1 can suppress nasopharyngeal carcinoma (NPC) tumor formation; however, the correlation between SPLUNC1expression and NPC patient prognosis has not been reported. In the present study, we used a large‐scale sample of 1015 tissue cores to detect SPLUNC1 expression and its association with patient prognosis. SPLUNC1 expression was reduced in NPC samples compared to nontumor nasopharyngeal epithelium tissues. Positive expression of SPLUNC1 in NPC predicted a better prognosis (disease‐free survival, P = 0.034; overall survival, P = 0.048). Cox's proportional hazards model revealed that SPLUNC1 could be a significant prognostic factor affecting disease‐free survival (P = 0.027). A cDNA micro‐array analyzed by significant analysis of micro‐array (SAM) and ingenuity pathway analysis (IPA) revealed that an indirect interaction existed between SPLUNC1 and retinoic acid (RA) in the cancer regulatory network. To further investigate the molecular mechanisms involved, we utilized several bioinformatics tools and identified 12 retinoid X receptors heterodimer binding sites in the promoter region of the SPLUNC1 gene. The transcriptional activity of the SPLUNC1 promoter was up‐regulated significantly by all‐trans‐retinoic acid (ATRA). SPLUNC1 and retinoic acid receptor expression were induced significantly by ATRA, and removal of ATRA led to a progressive loss of SPLUNC1 and retinoic acid receptor expression. ATRA inhibited proliferation and induced the differentiation of NPC cells. Interestingly, over‐expression of SPLUNC1 sensitized NPC cells to ATRA, whereas knockdown of SPLUNC1 in HNE1 cells increased cell viability. Under SPLUNC1 knockdown conditions, differentiation was reversed by ATRA treatment. We concluded that SPLUNC1 could potentially predict prognosis for NPC patients and play an important role in ATRA‐induced growth inhibition and differentiation in NPC cells.
Regulation of the catalytic activity of the human phosphatase PTPN4 by its PDZ domain
Authors: Maisonneuve Pierre , Caillet‐Saguy Célia , Raynal Bertrand , Gilquin Bernard , Chaffotte Alain , Pérez Javier , Zinn‐Justin Sophie , Delepierre Muriel , Buc Henri , Cordier Florence , Wolff Nicolas 
Published: August 2014

The human protein tyrosine phosphatase non‐receptor type 4 (PTPN4) prevents cells death. Targeting its PDZ domain abrogates this protection and triggers apoptosis. We demonstrate here that the PDZ domain inhibits the phosphatase activity of PTPN4. The mere binding of a PDZ ligand is sufficient to release the catalytic inhibition. We combined analytical ultracentrifugation, small angle X‐ray scattering and NMR to understand how the PDZ domain controls PTPN4 activity. We show that the physiologically active PTPN4 two‐domain, encompassing the PDZ and the phosphatase domains, adopts a predominant compact conformation in solution. The PDZ ligand binding restores the catalytic competence of PTPN4 disrupting the transient interdomain communication. This study strengthens the emerging notion that PDZ domains can act as regulators of enzyme activity and therefore are active players in the dynamic regulation of signaling pathways.Structured digital abstract

PTPN4_linker-PTP dephosphorylates pTyr peptide by enzymatic study (View interaction)

PTPN4_PDZ-PTP dephosphorylates pTyr peptide by enzymatic study (View interaction)
Do cities simulate climate change? A comparison of herbivore response to urban and global warming
Authors: Youngsteadt Elsa , Dale Adam G. , Terando Adam J. , Dunn Robert R. , Frank Steven D. 
Published: August 2014

AbstractCities experience elevated temperature, CO2, and nitrogen deposition decades ahead of the global average, such that biological response to urbanization may predict response to future climate change. This hypothesis remains untested due to a lack of complementary urban and long‐term observations. Here, we examine the response of an herbivore, the scale insect Melanaspis tenebricosa, to temperature in the context of an urban heat island, a series of historical temperature fluctuations, and recent climate warming. We survey M. tenebricosa on 55 urban street trees in Raleigh, NC, 342 herbarium specimens collected in the rural southeastern United States from 1895 to 2011, and at 20 rural forest sites represented by both modern (2013) and historical samples. We relate scale insect abundance to August temperatures and find that M. tenebricosa is most common in the hottest parts of the city, on historical specimens collected during warm time periods, and in present‐day rural forests compared to the same sites when they were cooler. Scale insects reached their highest densities in the city, but abundance peaked at similar temperatures in urban and historical datasets and tracked temperature on a decadal scale. Although urban habitats are highly modified, species response to a key abiotic factor, temperature, was consistent across urban and rural‐forest ecosystems. Cities may be an appropriate but underused system for developing and testing hypotheses about biological effects of climate change. Future work should test the applicability of this model to other groups of organisms.
The global spread of crop pests and pathogens
Authors: Bebber Daniel P. , Holmes Timothy , Gurr Sarah J. 
Published: August 2014

AbstractAimTo describe the patterns and trends in the spread of crop pests and pathogens around the world, and determine the socioeconomic, environmental and biological factors underlying the rate and degree of redistribution of crop‐destroying organisms.LocationGlobal.MethodsCurrent country‐ and state‐level distributions of 1901 pests and pathogens and historical observation dates for 424 species were compared with potential distributions based upon distributions of host crops. The degree of ‘saturation’, i.e. the fraction of the potential distribution occupied, was related to pest type, host range, crop production, climate and socioeconomic variables using linear models.ResultsMore than one‐tenth of all pests have reached more than half the countries that grow their hosts. If current trends continue, many important crop‐producing countries will be fully saturated with pests by the middle of the century. While dispersal increases with host range overall, fungi have the narrowest host range but are the most widely dispersed group. The global dispersal of some pests has been rapid, but pest assemblages remain strongly regionalized and follow the distributions of their hosts. Pest assemblages are significantly correlated with socioeconomics, climate and latitude. Tropical staple crops, with restricted latitudinal ranges, tend to be more saturated with pests and pathogens than temperate staples with broad latitudinal ranges. We list the pests likely to be the most invasive in coming years.Main conclusionsDespite ongoing dispersal of crop pests and pathogens, the degree of biotic homogenization of the globe remains moderate and regionally constrained, but is growing. Fungal pathogens lead the global invasion of agriculture, despite their more restricted host range. Climate change is likely to influence future distributions. Improved surveillance would reveal greater levels of invasion, particularly in developing countries.
Thermochemical and bacterial sulfate reduction in the Cambrian and Lower Ordovician carbonates in the Tazhong Area, Tarim Basin, NW China: evidence from fluid inclusions, C, S, and Sr isotopic data
Authors: Jia L. , Cai C. , Yang H. , Li H. , Wang T. , Zhang B. , Jiang L. , Tao X. 
Published: August 2014

AbstractPetrographic features, C, O, S, and Sr isotopes were determined, and fluid inclusions (FI) were analyzed on various stages of vug‐ and fracture‐fillings from the Cambrian and Lower Ordovician reservoirs in the Tazhong area, Tarim basin, NW China. The aim was to assess the origin of pyrite and anhydrite and the processes affecting sulfur during diagenesis of the carbonates. Pyrite from seven wells has δ34S values from −22‰ to +31‰. The pyrites with low δ34S values from −21.8‰ to −12.3‰ were found close to fracture‐filling calcites with vapor‐liquid double‐phase aqueous fluid inclusions homogenization temperatures (FI‐Th) from 55.7 to 73.2°C, salinities from 1.4wt% to 6.59wt% NaCl equiv and δ13C values from −2.3‰ to −14.2‰, indicating an origin from bacterial sulfate reduction by organic matter. Other sulfides with heavier δ34S values may have formed by thermochemical sulfate reduction (TSR) during two episodes. The earlier TSR in the Middle and Lower Cambrian resulted in pyrites and H2S having δ34S values from 30 to 33‰, close to those of bedded anhydrite and oilfield water (approximately 34‰). The later TSR is represented by calcites with δ13C values as light as −17.7‰ and FI‐Th of about 120–145°C, and pyrite and H2S with δ34S values close to those of the Upper Cambrian burial‐diagenetic anhydrite (between +14.8‰ and +22.6‰). The values of the anhydrite are significantly lighter than contemporary seawater sulfates. This together with 87Sr/86Sr values of anhydrite and TSR calcites from 0.7091 to 0.7125 suggests a source from the underlying Ediacaran seawater sulfate and detrital Sr contribution.
Effects of fibrolytic enzymes, molasses and lactic acid bacteria on fermentation quality of mixed silage of corn and hulless–barely straw in the Tibetan Plateau
Authors: Guo Gang , Yuan Xianjun , Li Longxin , Wen Aiyou , Shao Tao 
Published: August 2014

AbstractThe objective of present study was to investigate the effect of fibrolytic enzymes, molasses and lactic acid bacteria on fermentation quality of mixed silage of corn and hulless–barely straw in Tibet. The mixed silage was either untreated (control) or treated with fibrolytic enzymes (E, 0.1% fresh weight, FW), molasses (M, 4% FW), Lactobacillus plantarum (Lp, 6 log colony forming unit [cfu] g−1 FW), E + Lp and M + Lp. Triplicate silos were opened after 15, 30 and 45 days of ensiling, and the average ambient temperature during ensiling was about 10°C. Adding fibrolytic enzymes, molasses or L. plantarum alone improved fermentation quality of the mixed silage with lower (P < 0.05) pH, NH3‐N, acetic acid and butyric acid concentrations as compared to the control, and silage inoculated with L. plantarum showed better fermentation quality than fibrolytic enzymes or molasses treated silages (P < 0.05). The concentration of lactic acid in silages treated with combined additives was higher (P < 0.05) than silages treated with each of the three additives alone. Addition of fibrolytic enzymes with or without L. plantarum, both decreased (P < 0.05) the ratios of neutral detergent fiber to acid detergent lignin (ADL), acid detergent fiber to ADL, hemicellulose to ADL and cellulose to ADL. The present study suggested that application of L. plantarum together with fibrolytic enzymes or molasses to the mixed silage could further improve the mixed silage quality in comparison with using each of the three additives alone.
Is Inflation Targeting Still on Target? The Recent Experience of Latin America
Authors: Céspedes Luis Felipe , Chang Roberto , Velasco Andrés 
Published: August 2014

AbstractThis paper reviews the recent experience of a group of Latin American inflation‐targeting (IT) nations. We document repeated and large deviations from the standard IT framework: exchange market interventions have been widespread; the real exchange rate has often become a target of policy; and other non‐conventional policy tools, especially changes in reserve requirements, but occasionally also taxes and restrictions on international capital movements, have come into common use. As in developed nations, during the 2008–2009 crisis, issues of liquidity provision took centre stage. The emerging modified framework of monetary policy is found to have been generally effective during the crisis but raises several important policy questions.
EMPIRICAL ANALYSIS OF MUNICIPAL BOND PORTFOLIO STRUCTURE AND PERFORMANCE
Authors: Stock Duane 
Published: August 2014

AbstractThe introduction of municipal bond mutual funds in 1976 as an alternative for investors increases the importance of examining the factors that may affect the performance of municipal bond portfolios. Some sponsors of unit trusts claim that diversification across states, tax districts, and purpose of issue improves performance. This study finds only slight support for this type of diversification, and the conclusion is that the prime determinants of price volatility are maturity and risk‐premium.
AGENCY COSTS AND CAPTIVE FINANCE SUBSIDIARIES IN CANADA
Authors: Dipchand Cecil R. , Roberts Gordon S. , Viscione Jerry A. 
Published: August 2014

AbstractAgency theory is employed to formalize the intuitive rationale for the widespread practice of setting up captive finance subsidiaries: reduced agency costs of debt increase the firm's consolidated debt capacity. Of the two Canadian industries tested, firms forming captives had significantly higher use of debt in manufacturing but failed to show any significant difference for merchandising. In light of confounding influences from tax‐clientele effects, size difference, and support in tests on U.S. firms, the mixed finding should encourage further testing. The outcome of these tests suggests that it is potentially useful to think of captive finance subsidiaries in light of agency theory.
THE INFORMATION CONTENT OF DIVIDEND CHANGES
Authors: Woolridge J. Randall 
Published: August 2014

AbstractIn this study, the open empirical question as to whether or not dividends contain information is investigated. The study involves 200 stocks and 376 dividend announcements over the 1971 to 1977 period; measures of unexpected dividends are related to measures of abnormal returns for dividend changing stocks. This study is important for three reasons:
A tested ex ante dividend expectational model is used;
The analysis is centered on daily, as opposed to monthly, returns; and,
The influence of earnings on stock price is controlled explicitly.
The evidence indicates that abnormal stock returns vary in sign with unexpected dividends. The results are consistent with the hypothesis that dividends contain information.
REGULATORY INFLUENCES ON PORTFOLIO PERFORMANCE: SHORT SELLING AND REGULATION T
Authors: Burgess Richard C. , Tamarkin Maurry J. 
Published: August 2014

AbstractSeveral models are developed to examine the portfolio effect of short selling. Three things are demonstrated in this study. First, that for many assets, short selling is a useful strategy for reducing risk when constructing mean‐variance efficient portfolios. Second, Regulation T can be used in combination with short selling to further improve expected portfolio performance. Third, the performance of the suggested models is superior to previously suggested allocation models. Ex ante and ex post tests are conducted to arrive at the above conclusions.
PERSISTENT DEPENDENCE IN GOLD PRICES
Authors: Booth G. Geoffrey , Kaen Fred R. , Koveos Peter E. 
Published: August 2014

AbstractThe purpose of this paper is to analyze the behavior of gold prices during the last dozen years. Instead of employing the traditional short‐term analytical tools, however, rescaled range analysis is used to focus on what has become known as persistent or long‐term dependence. This type of behavior reveals itself in the form of extensive periods of similar behavior, often described as nonperiodic cycles. It is found that gold prices do exhibit persistent dependence. This finding suggests that, to be successful, market participants must develop strategies to deal with this phenomenon.
THE HEDGING EFFECTIVENESS OF FOREIGN CURRENCY FUTURES
Authors: Hill Joanne , Schneeweis Thomas 
Published: August 2014

AbstractThis study provides an initial analysis of the hedging potential of the foreign currency futures markets. Numerous studies exist on the pricing efficiency and hedging effectiveness of the foreign currency forward markets, but little research exists on the foreign currency futures market. An adequate price history has only recently become available to carry out such an investigation. Minimum risk hedges and hedging effectiveness measures are presented for five currencies: the British pound, German mark, Canadian dollar, Japanese yen and Swiss franc. Analysis indicates the relative desirability of positions in futures contracts to minimize the risk of spot currency exposure. Results also show hedging effectiveness increases with the investment horizon.
AN EXAMINATION OF FEDERAL AGENCY DEBT PRICING PRACTICES
Authors: Puglisi Donald J. , Vignola Anthony J. 
Published: August 2014

AbstractDebt issuance procedures for federally sponsored agency securities differ considerably from the methods used by the U.S. Treasury and most corporate and municipal debt issuers. This paper examines the debt issuing procedures of the three major federally sponsored agencies and the efficiency with which the fiscal agents for those agencies price new debt issues. The conclusions from the analysis are: (1) fiscal agents for the major federally sponsored agencies are extremely adept at estimating the equilibrium competitive yields for new debt issues; (2) pricing errors on new issues are generally due to factors beyond a fiscal agent's control, such as the volatility of debt market conditions; and (3) the debt pricing practices for federally sponsored agency securities are efficient and effective.
SECURITIES INVENTORIES AND EXCESS RETURNS
Authors: Van Horne James C. , Heaton Hal B. 
Published: August 2014

AbstractIn this paper, the inventory positions of government security dealers are analyzed for signs of their superior information relative to other participants in the market. Testing the 1966–1980 period on a monthly basis, it does not appear that information on the maturity composition of dealers' positions can be used, either concurrently or when it becomes publicly available, to earn excess returns.
THE EXISTENCE OF HETEROSCEDASTICITY AND ITS EFFECT ON ESTIMATES OF THE MARKET MODEL PARAMETERS
Authors: McDonald Bill , Morris Michael H. 
Published: August 2014

AbstractA number of recent studies have found significant evidence of heteroscedasticity in the market model. These studies have only documented the existence of heteroscedasticity and have not determined the actual impact of this econometric aberration in the estimation process. This study develops a more general specification to determine the effects of heteroscedasticity on the market model parameters. The consequences of this econometric problem in relation to efficiency‐bias, temporal stability of betas, and estimates of systematic risk are revealed in the estimation of a maximum likelihood specification.
INCORPORATION OF TAX CONSIDERATIONS INTO THE COMPUTATION OF DURATION
Authors: Hessel Christopher A. , Huffman Lucy T. 
Published: August 2014

AbstractIn this paper, the immunization process is extended to protect after‐tax income, and the duration indices for after‐tax immunization are derived. Selection of the appropriate index depends on individual investor differences in tax regulations. Attention is focused on the mutually exclusive decisions to amortize or not to amortize premia or discounts.
THE MARKET MODEL AS AN APPROPRIATE DESCRIPTION OF THE STOCHASTIC PROCESS GENERATING SECURITY RETURNS
Authors: Bey Roger P. 
Published: August 2014

AbstractThe objective of this research was to investigate whether the market model is an appropriate description of the stochastic process generating security returns. In contrast to previous studies which concentrated only on the stationarity ofβ, the emphasis in this research was to study the stationarity of the entire market model. Four statistical tests, cusum, cusum of squares, moving regression, and time‐trending regression, were used. The data base consisted of 200 securities and four time periods. The cusum of squares generally identified the largest number of nonstationary securities. However, the amount and composition of the nonstationary sets varied considerably both by statistical test and time period. The lack of consistency in the stationarity of the market model limits the predictability of stationarity and, hence, hinders the application of the market model. Serious questions are raised as to whether the market model is an appropriate description of the stochastic process generating security returns.