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Selected AbstractsHigh bacterial diversity of a waste gas-degrading community in an industrial biofilter as shown by a 16S rDNA clone libraryENVIRONMENTAL MICROBIOLOGY, Issue 11 2002Udo Friedrich Summary The bacterial diversity of an industrial biofilter used for waste gas abatement in an animal-rendering plant was investigated. A 16S rDNA clone library was generated and 444 clones were screened using computer-aided amplified ribosomal DNA restriction analysis (ARDRA). Of the screened clones, 60.8% showed unique ARDRA patterns and the remaining 174 clones were clustered into 65 groups. Almost full-length 16S rDNA sequences of 106 clones were determined and 90.5% of the clones were affiliated with the two phyla Proteobacteria and Bacteroidetes. Alpha -, Beta -, and Gammaproteobacteria accounted for 22.1, 17.6 and 18.6% respectively. Minor portions were affiliated with the Actinobacteria (2.0%), Firmicutes and Verrucomicrobia (both 1.0%), and the Deltaproteobacteria and Thermomicrobia (each 0.5%). Only six out of the 106 16S rDNA sequences exhibited similarities of more than 97% to classified bacterial species indicating that a substantial fraction of the clone sequences were derived from unknown taxa. It was also evaluated whether a database containing 281 computer-simulated bacterial rDNA fragment patterns generated from published reference sequences can be used for identification purposes. The data analysis demonstrated that this was possible only for a small number of clones, which were closely related to described bacterial strains. Rarefaction analysis of ARDRA clusters demonstrated that the 444 clones screened are insufficient to describe the entire diversity of the clone library. [source] Tracking cccDNA in chronic HBV infectionHEPATOLOGY, Issue 6 2004Hans Christian Spangenberg M.D. Hepatitis B virus (hepadnavirus) infections are maintained by the presence of a small and regulated number of episomal viral genomes [covalently closed circular DNA (cccDNA)] in the nuclei of infected cells. Although a number of studies have measured the mean copy number of cccDNA molecules in hepadnaviral-infected cells, the distribution of individual copy numbers have not been reported. Using a PCR-based assay, we examined the number of cccDNA molecules of the duck hepatitis B virus in single nuclei isolated from the liver of a chronically infected duck over the course of 131 days of infection. Nuclei were isolated from frozen serial biopsies and individually deposited into PCR microplates by flow sorting. Each nucleus was assayed by nested PCR for cccDNA and for cellular IFN-, genes as an internal control. We found that 90% of the nuclei assayed contained between 1 and 17 cccDNA molecules, with the remaining 10% containing more (90% confidence), and that differences in the mean number of copies and distribution of copy numbers occurred within the same animal at different times postinfection. Overall, the data suggest (i) that the number of cccDNA molecules per cell may fluctuate over time, and (ii) that, according to these fluctuations, a substantial fraction of cells may contain only one or a few copies. We infer from the results that infected hepatocytes express virus at different levels and that during cell division it is possible to segregate cells containing no cccDNA. (Copyright 2003, National Academy of Sciences, U.S.A.) [source] Sources and migration of volatile organic compounds in mixed-use buildingsINDOOR AIR, Issue 5 2010C. Jia Abstract, We examined concentrations and migration of volatile organic compounds (VOCs) in ten mixed-use buildings in southeast Michigan, USA. In an office and work zone in each building, air exchange rates (AERs) were measured using perfluorocarbon tracers, and over 96 VOC species were measured by GC/MS over a 7-day period. VOCs were then apportioned to sources in offices, work zones, and outdoors using a two-zone mass balance model. AERs averaged 3.9 h (0.2,14.2 h) in offices and 1.9 h (0.4,3.5 h) in work zones. The dominant VOCs included aromatics, terpenes and alkanes. VOC concentrations were uniform in the smaller spaces, and more variable in some of the very large spaces. Apportionments depended on the VOC and building, but emissions in industrial zones of buildings often migrated to office areas where they frequently accounted for the bulk of VOC concentrations. Outdoor sources accounted for most benzene and carbon tetrachloride, and a small fraction of aromatic and aliphatic compounds. This study shows that pollutant migration can be a significant and not uncommon problem in mixed-use buildings, and it demonstrates the need for better control of emissions and pollutant migration. Practical Implications Pollutant exposures in industrial, commercial, and institutional buildings arise from indoor and outdoor sources that can be identified, apportioned, and controlled with knowledge of emission sources and building airflows. We show that multi-tracer techniques are an effective and practical means of determining airflows and exchange rates in large buildings. In examining a set of mixed-use buildings, a substantial fraction of VOC exposures in otherwise relatively ,clean' offices is due to pollutant migration from ,dirty' zones of the building. This indicates the need for corrective actions to minimize exposures of office workers that are unwanted and probably unknown to building managers. These actions should include better control of emissions, isolation or control of air and pollutant flows between building zones, and documentation of the effectiveness of such measures when strong emission sources are present. [source] A 100-position robotic sample changer for powder diffraction with low-background vacuum chamberJOURNAL OF APPLIED CRYSTALLOGRAPHY, Issue 2 2010S. R. Olsen At the new Australian OPAL research reactor, experiments carried out at room temperature use a substantial fraction of beam time on the high-resolution powder diffractometer, Echidna. With an average data collection time of 2,h and a complicated safety interlock system to protect users, the need for a fully automated and remotely controlled system was quickly realized. This report presents a solution based on a commercial four-axis robot capable of loading samples from two 50-position sample trays, in any order, into an automatically evacuated chamber. This chamber significantly reduced background signal arising from air scattering, with the effect being especially pronounced at low and high 2, angles. In the case of textured or inhomogeneous samples, the system may be re-configured so that the robot rotates the sample in the beam or translates it vertically through the beam. [source] Native American impacts on fire regimes of the California coastal rangesJOURNAL OF BIOGEOGRAPHY, Issue 3 2002Jon E. Keeley Aim Native American burning impacts on California shrubland dominated landscapes are evaluated relative to the natural lightning fire potential for affecting landscape patterns. Location Focus was on the coastal ranges of central and southern California. Methods Potential patterns of Indian burning were evaluated based upon historical documents, ethnographic accounts, archaeological records and consideration of contemporary land management tactics. Patterns of vegetation distribution in this region were evaluated relative to environmental factors and the resilience of the dominant shrub vegetation to different fire frequencies. Results Lightning fire frequency in this region is one of the lowest in North America and the density of pre-Columbian populations was one of the highest. Shrublands dominate the landscape throughout most of the region. These woody communities have weak resilience to high fire frequency and are readily displaced by annual grasses and forbs under high fire frequency. Intact shrublands provided limited resources for native Americans and thus there was ample motivation for using fire to degrade this vegetation to an open mosaic of shrubland/grassland, not unlike the agropastoral modification of ecologically related shrublands by Holocene peoples in the Mediterranean Basin. Alien-dominated grasslands currently cover approximately one-quarter of the landscape and less than 1% of these grasslands have a significant native grass presence. Ecological studies in the Californian coastal ranges have failed to uncover any clear soil or climate factors explaining grassland and shrubland distribution patterns. Main conclusions Coastal ranges of California were regions of high Indian density and low frequency of lightning fires. The natural vegetation dominants on this landscape are shrubland vegetation that often form dense impenetrable stands with limited resources for Native Americans. Natural fire frequencies are not high enough to maintain these landscapes in habitable mixtures of shrublands and grasslands but such landscape mosaics are readily produced with additional human subsidy of ignitions. It is hypothesized that a substantial fraction of the landscape was type converted from shrubland to grassland and much of the landscape that underwent such type conversion has either been maintained by Euro-American land management practices or resisted recolonization of native shrublands. It appears that these patterns are disturbance dependent and result from anthropogenic alteration of landscapes initiated by Native Americans and sustained and expanded upon by Euro-American settlers. [source] Private Enforcement of Corporate Law: An Empirical Comparison of the United Kingdom and the United StatesJOURNAL OF EMPIRICAL LEGAL STUDIES, Issue 4 2009John Armour It is often assumed that strong securities markets require good legal protection of minority shareholders. This implies both "good" law,principally, corporate and securities law,and enforcement, yet there has been little empirical analysis of enforcement. We study private enforcement of corporate law in two common-law jurisdictions with highly developed stock markets, the United Kingdom and the United States, examining how often directors of publicly traded companies are sued, and the nature and outcomes of those suits. We find, based a comprehensive search for filings over 2004,2006, that lawsuits against directors of public companies alleging breach of duty are nearly nonexistent in the United Kingdom. The United States is more litigious, but we still find, based on a nationwide search of court decisions between 2000,2007, that only a small percentage of public companies face a lawsuit against directors alleging a breach of duty that is sufficiently contentious to result in a reported judicial opinion, and a substantial fraction of these cases are dismissed. We examine possible substitutes in the United Kingdom for formal private enforcement of corporate law and find some evidence of substitutes, especially for takeover litigation. Nonetheless, our results suggest that formal private enforcement of corporate law is less central to strong securities markets than might be anticipated. [source] Predation and the persistence of melanic male mosquitofish (Gambusia holbrooki)JOURNAL OF EVOLUTIONARY BIOLOGY, Issue 3 2004L. Horth Abstract The empirical reasons for the persistent rarity of a genotype are typically complex and tedious to identify, particularly in nature. Yet rare morphs occur in a substantial fraction of phenotypic polymorphisms. A colour polymorphism has persisted for decades in the eastern mosquitofish, yet why this is so remains obscure. Here, I report the results of (1) intensive sampling at 45 natural sites to obtain the frequency distribution of the melanic (black) mosquitofish morph in Florida, (2) predation trials, conducted independently in mesocosms, with three different predatory species and (3) two mark-recapture studies, conducted in nature. This work (1) documents the rarity of melanic mosquitofish in nature, (2) demonstrates that melanic males experience a selective advantage over silver males in the presence of predators, (3) indicates no difference in the colour morphs, survival at a natural site essentially devoid of these predators, although suggesting a higher rate of recapture for melanic males at a site rife with predators. Overall, selective predation appears to contribute to the persistence of the melanic morph, despite its rarity in nature. [source] Efficient recognition of protein fold at low sequence identity by conservative application of Psi-BLAST: validation,JOURNAL OF MOLECULAR RECOGNITION, Issue 2 2005F. J. Stevens Abstract A substantial fraction of protein sequences derived from genomic analyses is currently classified as representing ,hypothetical proteins of unknown function'. In part, this reflects the limitations of methods for comparison of sequences with very low identity. We evaluated the effectiveness of a Psi-BLAST search strategy to identify proteins of similar fold at low sequence identity. Psi-BLAST searches for structurally characterized low-sequence-identity matches were carried out on a set of over 300 proteins of known structure. Searches were conducted in NCBI's non-redundant database and were limited to three rounds. Some 614 potential homologs with 25% or lower sequence identity to 166 members of the search set were obtained. Disregarding the expect value, level of sequence identity and span of alignment, correspondence of fold between the target and potential homolog was found in more than 95% of the Psi-BLAST matches. Restrictions on expect value or span of alignment improved the false positive rate at the expense of eliminating many true homologs. Approximately three-quarters of the putative homologs obtained by three rounds of Psi-BLAST revealed no significant sequence similarity to the target protein upon direct sequence comparison by BLAST, and therefore could not be found by a conventional search. Although three rounds of Psi-BLAST identified many more homologs than a standard BLAST search, most homologs were undetected. It appears that more than 80% of all homologs to a target protein may be characterized by a lack of significant sequence similarity. We suggest that conservative use of Psi-BLAST has the potential to propose experimentally testable functions for the majority of proteins currently annotated as ,hypothetical proteins of unknown function';. Copyright © 2004 John Wiley & Sons, Ltd. [source] Three-photon microscopy shows that somatic release can be a quantitatively significant component of serotonergic neurotransmission in the mammalian brainJOURNAL OF NEUROSCIENCE RESEARCH, Issue 15 2008S.K. Kaushalya Abstract Recent experiments on monoaminergic neurons have shown that neurotransmission can originate from somatic release. However, little is known about the quantity of monoamine available to be released through this extrasynaptic pathway or about the intracellular dynamics that mediate such release. Using three-photon microscopy, we directly imaged serotonin autofluorescence and investigated the total serotonin content, release competence, and release kinetics of somatic serotonergic vesicles in the dorsal raphe neurons of the rat. We found that the somata of primary cultured neurons contain a large number of serotonin-filled vesicles arranged in a perinuclear fashion. A similar distribution is also observed in fresh tissue slice preparations obtained from the rat dorsal raphe. We estimate that the soma of a cultured neuron on an average contains about 9 fmoles of serotonin in about 450 vesicles (or vesicle clusters) of ,370 nm average diameter. A substantial fraction (>30%) of this serotonin is released with a time scale of several minutes by K+ -induced depolarization or by para-chloroamphetamine treatment. The amount of releasable serotonin stored in the somatic vesicles is comparable to the total serotonin content of all the synaptic vesicles in a raphe neuron, indicating that somatic release can potentially play a major role in serotonergic neurotransmission in the mammalian brain. © 2008 Wiley-Liss, Inc. [source] Stability of oleuropein in the human proximal gutJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 2 2009Constantinos Markopoulos Abstract Objectives We aimed to assess the intralumenal stability of oleuropein in human gastric and small intestinal contents. We additionally aimed to assess the stability characteristics of oleuropein in media simulating the intralumenal conditions. Methods The intralumenal stability of oleuropein was assessed in aspirates from the stomach and the upper small intestine of healthy volunteers collected under both fasted and fed state conditions and in media simulating the intralumenal environment. Key findings Oleuropein degraded in aspirates collected in the fasted state. When the initial concentration was about 50 ,g/ml (close to expected intragastric concentration after single dose of commercially available products of oleuropein) the mean zero-order half-life of oleuropein in aspirates collected from the fasted small intestine was estimated to be 3.14 ± 0.08 h at 37°C (i.e. after oral administration in the fasted state, a substantial fraction of oleuropein degrades before reaching the intestinal mucosa). In contrast, oleuropein was stable in aspirates collected from the fed stomach; in small intestinal contents aspirated in the fed state the estimated zero-order degradation half-life was at least 12 h. Conclusions These data suggest that oleuropein should not have substantial intralumenal stability problems when administered in the fed state. Data collected in media simulating the intragastric and intraintestinal environment suggest that pH affects the stability of oleuropein only at low pH values (of about 2). At higher pHs degradation characteristics are at least partly affected by the presence of other scavengers of reactive oxygen species in the medium. [source] Identification of a cellular protein specifically interacting with the precursor of the hepatitis B e antigenJOURNAL OF VIRAL HEPATITIS, Issue 3 2001S. Salhi In hepatitis B virus (HBV) the precore gene encodes a protein from which derives P22, the precursor of the mature secreted hepatitis B virus e antigen (HBeAg). Circumstantial evidences suggest that HBeAg and/or its precursor P22 are important for establishing persistent infection. Although P22 is essentially present in the secretory pathway, a substantial fraction has been found in the cytosol. In order to get new insights into the biological function of P22, we looked for cellular proteins which could strongly associate with this protein. Using immunoprecipitation studies on human cell extracts, we found that a non-secreted cellular protein of about 32 kDa (P32) bound with a high specificity to P22. P32 associated neither with HBeAg nor with the viral core protein P21 which exhibits the same amino acids sequence as P22 but is N-terminally shorter by 10 residues. We also demonstrated that this interaction depended on the presence of the P22 C-terminal domain. Our data argues for a potential biological function of P22. [source] Corruption, Productivity and SocialismKYKLOS INTERNATIONAL REVIEW OF SOCIAL SCIENCES, Issue 2 2003Geoffrey Wyatt Summary The level of productivity is correlated across countries with measures of (lack of) corruption, but this appears to be due to a common association of these variables with measures of civil infrastructure, here measured by a combination of governance indexes labelled ,rule of law' and ,government effectiveness'. New instruments based on the size- and spatial-distributions of cities within the countries of the world were constructed in order to explore the causal relationships between civil infrastructure and productivity. Civil infrastructure accounts for a substantial fraction of the global variation in output per worker across countries. Within this empirical pattern there is a systematic deviation associated with the current and former socialist states, which have both lower productivity and inferior civil infrastructure than would be predicted for otherwise similar non-socialist states. However, for a given level of the index of civil infrastructure these states are also shown to have a higher level of productivity than otherwise similar non-socialist states. The unconditionally low productivity of socialist states is attributed entirely to the indirectly deleterious effects that socialism had on civil infrastructure, which more than offset its directly positive effect on output. [source] Spatial population structure in a patchily distributed beetleMOLECULAR ECOLOGY, Issue 4 2001Tomas Roslin Abstract The dynamics and evolution of populations will critically depend on their spatial structure. Hence, a recent emphasis on one particular type of structure , the metapopulation concept of Levins , can only be justified by empirical assessment of spatial population structures in a wide range of organisms. This paper focuses on Aphodius fossor, a dung beetle specialized on cattle pastures. An agricultural database was used to locate nearly 50 000 local populations of A. fossor in Finland. Several independent methods were then used to quantify key processes in this vast population system. Allozyme markers and mitochondrial DNA (mtDNA) sequences were applied to examine genetic differentiation of local populations and to derive indirect estimates of gene flow. These estimates were compared to values expected on the basis of direct observations of dispersing individuals and assessments of local effective population size. Molecular markers revealed striking genetic homogeneity in A. fossor. Differentiation was only evident in mtDNA haplotype frequencies between the isolated Åland islands and the Finnish mainland. Thus, indirect estimates of gene flow agreed with direct observations that local effective population size in A. fossor is large (hundreds of individuals), and that in each generation, a substantial fraction (approximately one-fifth) of the individuals move between populations. Large local population size, extreme haplotype diversity and a high regional incidence of A. fossor all testify against recurrent population turnover. Taken together, these results provide strong evidence that the whole mainland population of A. fossor is better described as one large ,patchy population', with substantial movement between relatively persistent local populations, than as a classical metapopulation. [source] What is the largest Einstein radius in the universe?MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 2 2009Masamune Oguri ABSTRACT The Einstein radius plays a central role in lens studies as it characterizes the strength of gravitational lensing. In particular, the distribution of Einstein radii near the upper cut-off should probe the probability distribution of the largest mass concentrations in the universe. Adopting a triaxial halo model, we compute expected distributions of large Einstein radii. To assess the cosmic variance, we generate a number of Monte Carlo realizations of all-sky catalogues of massive clusters. We find that the expected largest Einstein radius in the universe is sensitive to parameters characterizing the cosmological model, especially ,8: for a source redshift of unity, they are 42+9,7, 35+8,6 and 54+12,7 arcsec (errors denote 1, cosmic variance), assuming best-fitting cosmological parameters of the Wilkinson Microwave Anisotropy Probe five-year (WMAP5), three-year (WMAP3) and one-year (WMAP1) data, respectively. These values are broadly consistent with current observations given their incompleteness. The mass of the largest lens cluster can be as small as , 1015 M,. For the same source redshift, we expect in all sky ,35 (WMAP5), ,15 (WMAP3) and ,150 (WMAP1) clusters that have Einstein radii larger than 20 arcsec. For a larger source redshift of 7, the largest Einstein radii grow approximately twice as large. Whilst the values of the largest Einstein radii are almost unaffected by the level of the primordial non-Gaussianity currently of interest, the measurement of the abundance of moderately large lens clusters should probe non-Gaussianity competitively with cosmic microwave background experiments, but only if other cosmological parameters are well measured. These semi-analytic predictions are based on a rather simple representation of clusters, and hence calibrating them with N -body simulations will help to improve the accuracy. We also find that these ,superlens' clusters constitute a highly biased population. For instance, a substantial fraction of these superlens clusters have major axes preferentially aligned with the line-of-sight. As a consequence, the projected mass distributions of the clusters are rounder by an ellipticity of ,0.2 and have , 40,60 per cent larger concentrations compared with typical clusters with similar redshifts and masses. We argue that the large concentration measured in A1689 is consistent with our model prediction at the 1.2, level. A combined analysis of several clusters will be needed to see whether or not the observed concentrations conflict with predictions of the flat ,-dominated cold dark matter model. [source] Constraints on the initial mass function of the first starsMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 2 2006Raffaella Schneider ABSTRACT Motivated by theoretical predictions that the first stars were predominantly very massive, we investigate the physics of the transition from an early epoch dominated by massive Pop III stars to a later epoch dominated by familiar low-mass Pop II/I stars by means of a numerically generated catalogue of dark matter haloes coupled with a self-consistent treatment of chemical and radiative feedback. Depending on the strength of the chemical feedback, Pop III stars can contribute a substantial fraction (several per cent) of the cosmic star formation activity even at moderate redshifts, z, 5. We find that the three z, 10 sources tentatively detected in Near Infrared Camera and Multi-Object Spectrometer (NICMOS) Ultra Deep Fields (UDFs) should be powered by Pop III stars, if these are massive; however, this scenario fails to reproduce the derived Wilkinson Microwave Anisotropy Probe (WMAP) electron scattering optical depth. Instead, both the UDFs and WMAP constraints can be fulfilled if stars at any time form with a more standard, slightly top-heavy, Larson initial mass function. [source] On the misalignment of jets in microquasarsMONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2002Thomas J. Maccarone Abstract We discuss the time-scales for alignment of black hole and accretion disc spins in the context of binary systems. We show that for black holes that are formed with substantial angular momentum, the alignment time-scales are likely to be at least a substantial fraction of the lifetimes of the systems. This result explains the observed misalignment of the disc and the jet in the microquasar GRO J 1655-40 and in SAX J 1819-2525 as probably being caused by the Bardeen,Petterson effect. We discuss the implications of these results on the mass estimate for GRS 1915+105, which has assumed the jet to be perpendicular to the orbital plane of the system and may hence be an underestimate. We show that the time-scales for the spin alignment in Cygnus X-3 are consistent with the likely misalignment of disc and jet in that system, and that this is suggested by the observational data. [source] Should children at risk for familial adenomatous polyposis be screened for hepatoblastoma and children with apparently sporadic hepatoblastoma be screened for APC germline mutations?,PEDIATRIC BLOOD & CANCER, Issue 6 2006Stefan Aretz MD Abstract Background Hepatoblastoma (HB) is the most frequent liver tumor in childhood, occurring in the first few years of life. Surgery combined with chemotherapy has resulted in dramatic improvements in prognosis. However, even today, about one quarter of affected children do not survive the disease. Compared to the general population, the risk of HB is 750,7,500 times higher in children predisposed to familial adenomatous polyposis (FAP), an autosomal-dominant cancer predispostion syndrome caused by germline mutations in the tumor suppressor gene APC. Only limited data exist about the frequency of APC germline mutations in cases of apparently sporadic HB without a family history of FAP. Procedure In our sample of 1,166 German FAP families, all known cases of HB were registered. In addition, 50 patients with apparently sporadic HB were examined for APC germline mutations. Results In the FAP families, seven unrelated cases of HB are documented; three had been detected at an advanced stage. In patients with apparently sporadic HB, germline mutations in the APC gene were identified in 10%. Conclusions These data raise the issue of the appropriate screening for HB in children of FAP patients. To date, the efficiency of surveillance for HB is unclear. In Beckwith,Wiedemann syndrome (BWS), recent studies suggest an earlier detection of both Wilms tumor and HB by frequent screening. We discuss the rationale and implications of a screening program; besides the examination procedure itself, screening for HB in children of FAP patients would have important consequences for the policy of predictive testing in FAP. In a substantial fraction of sporadic HB, the disease is obviously the first manifestation of a de novo FAP. These patients should be identified by routine APC mutation screening and undergo colorectal surveillance thereafter. Pediatric Blood Cancer 2006;47:811,818. © 2005 Wiley-Liss, Inc. [source] Sources of urinary proteins and their analysis by urinary proteomics for the detection of biomarkers of diseasePROTEOMICS - CLINICAL APPLICATIONS, Issue 9 2009Bruce A. Julian Abstract Renal disorders account for a substantial fraction of the budget for health care in many countries. Proteinuria is a frequent manifestation in afflicted patients, but the origin of the proteins varies based on the nature of the disorder. The emerging field of urinary proteomics has the potential to replace kidney biopsy as the diagnostic procedure of choice for patients with some glomerular forms of renal disease. To fully realize this potential, it is vital to understand the basis for the urinary excretion of protein in physiological and pathological conditions. In this review, we discuss the structure of the nephron, the functional unit of the kidney, and the process by which proteins/peptides enter the urine. We discuss several aspects of proteinuria that impact the proteomic analysis of urine of patients with renal diseases. [source] A Structural Model of Australia as a Small Open EconomyTHE AUSTRALIAN ECONOMIC REVIEW, Issue 1 2009Kristoffer P. Nimark This paper sets up and estimates a structural model of Australia as a small open economy using Bayesian techniques. Unlike other recent studies, the paper shows that a small micro-founded model can capture the open economy dimensions quite well. Specifically, the model attributes a substantial fraction of the volatility of domestic output and inflation to foreign disturbances, close to what is suggested by unrestricted VAR studies. The paper also investigates the effects of various exogenous shocks on the Australian economy. [source] PRICE-SETTING BEHAVIOR IN TURKISH INDUSTRIES: EVIDENCE FROM SURVEY DATATHE DEVELOPING ECONOMIES, Issue 4 2008E30; D40 This study investigates the price-setting behavior of Turkish industries based on the results of a survey that was conducted by the Central Bank of the Republic of Turkey. The results show that, under normal conditions, the majority of the firms follow a time-dependent pricing rule but when significant events occur a substantial fraction of them alter their behavior to state-dependent reviewing. The median Turkish firm reviews its prices every month, but changes its prices four times a year. Price reviews and changes are affected by: the market share, price discrimination, customer type, firm size, and the existence of regulated prices. [source] Conformational features of crystal-surface cellulose from higher plantsTHE PLANT JOURNAL, Issue 6 2002Remco J. Viëtor Summary Native cellulose in higher plants forms crystalline fibrils a few nm across, with a substantial fraction of their glucan chains at the surface. The accepted crystal structures feature a flat-ribbon 21 helical chain conformation with every glucose residue locked to the next by hydrogen bonds from O-3, to O-5 and from O-2 to O-6,. Using solid-state NMR spectroscopy we show that the surface chains have a different C-6 conformation so that O-6 is not in the correct position for the hydrogen bond from O-2. We also present evidence consistent with a model in which alternate glucosyl residues are transiently or permanently twisted away from the flat-ribbon conformation of the chain, weakening the O-3, , 0-5 hydrogen bond. Previous molecular modelling and the modelling studies reported here indicate that this ,translational' chain conformation is energetically feasible and does not preclude binding of the surface chains to the interior chains, because the surface chains share the axial repeat distance of the 21 helix. Reduced intramolecular hydrogen bonding allows the surface chains to form more hydrogen bonds to external molecules in textiles, wood, paper and the living plant. [source] Detection of Undiagnosed Diabetes and Prediabetic States in High-risk Emergency Department PatientsACADEMIC EMERGENCY MEDICINE, Issue 5 2009Michelle A. Charfen MD Abstract Background:, Diabetes is often not diagnosed until complications appear, and one-third of those with diabetes may be undiagnosed. Prediabetes and diabetes are conditions in which early detection would be appropriate, because the duration of hyperglycemia is a predictor of adverse outcomes, and there are effective interventions to prevent disease progression and to reduce complications. Objectives:, The objectives were to determine the prevalence of diabetes mellitus and prediabetes in emergency department (ED) patients with an elevated random glucose or risk factors for diabetes but without previously diagnosed diabetes and to identify which at-risk ED patients should be considered for referral for confirmatory diagnostic testing. Methods:, This two-part study was composed of a prospective 2-year cohort study, and a 1-week cross-sectional survey substudy, set in an urban ED in Los Angeles County, California. A convenience sample was enrolled of 528 ED patients without previously diagnosed diabetes with either 1) a random serum glucose , 140 mg/dL regardless of the time of last food intake or a random serum glucose , 126 mg/dL if more than 2 hours since last food intake or 2) at least two predefined diabetes risk factors. Measurements included presence of diabetes risk factors, ED glucose, cortisol, insulin and glycosylated hemoglobin (HbA1c), and 2-hour oral glucose tolerance test results, administered at 6-week follow-up. Results:, Glycemic status was confirmed at follow-up in 256 (48%) of the 528 patients. Twenty-seven (11%) were found to have diabetes, 141 (55%) had prediabetes, and 88 (34%) had normal results. Age, ED glucose, HbA1c, cortisol, and random serum glucose , 140 mg/dL were associated with both diabetes and prediabetes on univariate analysis. A random serum glucose , 126 mg/dL after 2 hours of fasting was associated with diabetes but not prediabetes; ED cortisol, insulin, age , 45 years, race, and calculated body mass index (BMI) were associated with prediabetes but not diabetes. In multivariable models, among factors measurable in the ED, the only independent predictor of diabetes was ED glucose, while ED glucose, age , 45 years, and symptoms of polyuria and polydipsia were independent predictors of prediabetes. All at-risk subjects with a random ED blood glucose > 155 mg/dL had either prediabetes or diabetes on follow-up testing. Conclusions:, A substantial fraction of this urban ED study population was at risk for undiagnosed diabetes and prediabetes, and among the at-risk patients referred for follow-up, the majority demonstrated diabetes or prediabetes. Notably, all patients with two risk factors and a random serum glucose > 155 mg/dL were later diagnosed with prediabetes or diabetes. Consideration should be given to referring ED patients with risk factors and a random glucose > 155 mg/dL for follow-up testing. [source] China's Energy in Transition: Regional and Global ImplicationsASIAN ECONOMIC POLICY REVIEW, Issue 1 2006Tianshu CHU China is the largest energy user in Asia and the second largest in the world after the US. This paper documents substantial changes of the structure of China's energy use over the past decades. It explores the puzzling phenomena of China's low gross domestic product elasticity of energy consumption. Econometric analysis applying the AutoRegressive Integrated Moving Average model finds that factors such as institutional reforms and structural change can account for a substantial fraction of the downward impacts on the elasticity level. The paper also studies the future energy growth and energy security issues in China, and examines the regional and global impacts of China's rapidly growing energy consumption. [source] Proteome analysis of antibody-producing CHO cell lines with different metabolic profilesBIOTECHNOLOGY & BIOENGINEERING, Issue 2 2007Deborah E. Pascoe Abstract Two-dimensional gel electrophoresis and tandem mass spectrometry were used to identify proteins associated with a metabolic shift during fed-batch cultures of two recombinant antibody-producing CHO cell lines. The first cell line underwent a marked change in lactate metabolism during culture, initially producing lactate and then consuming it, while the second cell line produced lactate for a similar duration but did not later consume it. The first cell line displayed a declining specific antibody productivity during culture, correlating to the 2-D gel results and the intracellular antibody concentration determined by HPLC. Several statistical analysis methods were compared during this work, including a fixed fold-change criterion and t -tests using standard deviations determined in several ways from the raw data and mathematically transformed data. Application of a variance-stabilizing transformation enabled the use of a global empirical standard deviation in the t -tests. Most of the protein spots changing in each cell line did not change significantly in the other cell line. A substantial fraction of the changing proteins were glycolytic enzymes; others included proteins related to antibody production, protein processing, and cell structure. Enolase, pyruvate kinase, BiP/GRP78, and protein disulfide isomerase were found in spots that changed over time in both cell lines, and some protein changes differed from previous reports. These data provide a foundation for future investigation of metabolism in industrially relevant mammalian cell culture processes, and suggest that along with differences between cell types, the proteins expressed in cultures with low lactate concentrations may depend on how those conditions were generated. Biotechnol. Bioeng. 2007;98: 391,410. © 2007 Wiley Periodicals, Inc. [source] Putative common origin of two MLH1 mutations in Italian-Quebec hereditary non-polyposis colorectal cancer familiesCLINICAL GENETICS, Issue 2 2004I Thiffault Hereditary non-polyposis colorectal cancer (HNPCC) is one of the most common inherited cancer syndromes, accounting for 3,5% of all cases of colorectal cancer. In most HNPCC families, the disease is caused by a germline mutation in MLH1 or MSH2. In some populations, founder mutations appear to explain a substantial fraction of HNPCC. We report here the identification and preliminary characterization of two putative MLH1 founder mutations. The mutation MLH1c.1831delAT was shown to segregate in two Quebec families of Italian origin who fulfilled the Amsterdam criteria for HNPCC. Haplotype analysis using five intragenic microsatellite/single nucleotide polymorphism markers spanning MLH1 on chromosome 3 showed that these two unrelated families share an identical haplotype. In addition, two other Italian kindred whose affected members carry MLH1g.IVS6 + 3A>G also share a common haplotype, suggesting that, similarly, the latter mutation has a common origin. These mutations are the first putative founder MLH1 mutations to be identified in HNPCC kindred of Italian origin. [source] Spectroscopic Diagnostics of Pulsed arc Plasmas for Particle GenerationCONTRIBUTIONS TO PLASMA PHYSICS, Issue 8 2008K. Behringer Abstract Pulsed arc plasmas were diagnosed by means of emission spectroscopy. A capacitor was discharged through argon and hydrogen leading to a few cycles of damped current oscillation with ,120 ,s period and 5-12 kA maximum current. Spectroscopic measurements in the visible range were carried out in order to characterise the electron temperature and density in the arc channel as well as electron and gas temperatures in the afterglow plasmas. Spectra were integrated over 10 ,s time windows and shifted in time from pulse to pulse. The plasmas also contained substantial fractions of electrode material (brass), namely copper and zinc. The electron density was measured in the conventional way from the broadening of H, or from the Ar I Stark width. In the arc channel, it ranged from about 3 · 1022 to 2 · 1023 m,3. The broadening of Zn II lines could also be used. Ratios of Ar I to Ar II and of Zn I to Zn II line intensities were analysed for the electron temperature. Line pairs were found which lay conveniently close in one frame of the spectrometer allowing automatic on-line analysis without relying on reproducibility. Atomic physics models including opacity were developed for Ar II and Zn II in order to check the existence of a Boltzmann distribution of their excited states. These calculations showed that the observed levels were in fact close to thermodynamic equilibrium, in particular, if the resonance lines were optically thick. Electron temperature measurements yielded values between 14000 K and 21000 K. The gas temperature in the afterglow, where particles should have formed, was derived from the rotational and vibrational temperatures of C2 molecular bands. Ratios between Cu I line intensities yielded the electron temperatures. Both were found to be a few 1000 K. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] | ||||||||||||||||||||||||||||