bluuebunny/crossref_metadata_2025 huggingface dataset:
Protein Induced by Vitamin K Antagonist‐II (PIVKA‐II) Is a Reliable Prognostic Factor in Small Hepatocellular Carcinoma
Authors: Kim Jong Man , Hyuck Choon , Kwon David , Joh Jae‐Won , Lee Joon Hyeok , Paik Seung Woon , Park Cheol Keun
Published: February 2013

Background

Hepatocellular carcinoma (HCC) <2 cm in diameter has a favorable prognosis. Therefore surgical resection of small HCC is associated with good outcomes. However, the predisposing factors of prognosis following resection of HCC remain ill‐defined. The aims of the present study were to identify the clinicopathologic characteristics and outcomes of patients with small HCC and analyze the predisposing factors for tumor recurrence after surgery.

Methods

We retrospectively reviewed 180 patients with small HCC who underwent hepatectomy between 2006 and 2010. Independent predictors of tumor recurrence were identified with Cox regression analysis.

Results

The 1‐year, 3‐year, and 5‐year disease‐free survival rates and overall survival rates were 83.7, 68.0, 65.3, and 98.9, 96.5, 92.7 %, respectively. Multivariate analysis reported that protein induced by the vitamin K antagonist‐II (PIVKA‐II) ≥200 mAU/mL, alkaline phosphatase (ALP) ≥80 IU/mL, and microvascular invasion were important predisposing factors for tumor recurrence. Elevated serum PIVKA‐II level was associated with microvascular invasion in small HCC, which was a powerful predisposing factor.

Conclusions

Although small HCC is generally associated with a good prognosis, serum PIVKA‐II level ≥200 mAU/mL, ALP ≥ 80 IU/L, and microvascular invasion were predisposing factors for tumor recurrence. These factors can be used to stratify patients with respect to recurrence after resection. Elevated PIVKA‐II was closely associated with microvascular invasion in small HCC. These data emphasize the importance of PIVKA‐II in small HCC.
Yarrowia lipolytica: the novel and promising 2-phenylethanol producer
Authors: Celińska E , Kubiak P , Białas W , Dziadas M , Grajek W
Published: February 2013

This is the first report on the ability of Yarrowia lipolytica strains to produce 2-phenylethanol (2-PE), which has not been identified for this species to date. 2-PE is a valuable aroma compound of rose-like odor. Its isolation from the other than microbial source—rose petals, is limited by the substrate availability. Thus, this chemical compound constitutes an attractive product for biotechnological conversions. To date, the ability to produce 2-PE has been described for such genera as Saccharomyces sp., Kluyveromyces sp., Geotrichum sp., and Pichia sp. This report provides evidence that Y. lipolytica is a novel 2-PE producer. Moreover, the titers of 2-PE obtained in Y. lipolytica NCYC3825 non-optimized cultures, nearly 2 g/l, are competitive to titers obtained by the other species.
The Special Sign Indeterminacy of the Direct-Fitting Parafac2 Model: Some Implications, Cautions, and Recommendations for Simultaneous Component Analysis
Authors: Helwig Nathaniel E.
Published: February 2013

Parafac2 is the most flexible Simultaneous Component Analysis (SCA) model that produces an essentially unique solution. In this paper, we discuss how Parafac2’s special sign indeterminacy affects applications of SCA, and we reveal how an external criterion variable can be used to ensure that estimated Parafac2 weights are meaningfully signed across the levels of the nesting mode. We present an example with real data from clinical psychology that illustrates the importance of Parafac2’s special sign indeterminacy, as well as the effectiveness of our proposed solution. We also discuss the implications of our results for general applications of SCA.
Interactions of Linoleic and Alpha‐Linolenic Acids in the Development of Fatty Acid Alterations in Cystic Fibrosis
Authors: Katrangi Waddah , Lawrenz Joshua , Seegmiller Adam C. , Laposata Michael
Published: February 2013

Patients with cystic fibrosis (CF) exhibit characteristic polyunsaturated fatty acid abnormalities, including low linoleic acid and high arachidonic acid levels that are thought to contribute to the pathophysiology of this disease. Recent studies indicate that changes in fatty acid metabolism are responsible for these abnormalities. This study examines the role of fatty acid substrate concentrations in the development of these alterations in a cultured cell model of CF. By incubating cells with varying concentrations of exogenous fatty acids, it shows that increasing the concentration of substrates from the parallel n‐3 and n‐6 polyunsaturated fatty acid pathways (linoleic acid and alpha‐linolenic acid, respectively) not only increases formation of the products in that pathway, but also reduces metabolism in the parallel pathway. In particular, we demonstrate that high levels of linoleic acid and low levels of alpha‐linolenic acid are required to observe the typical fatty acid alterations of cystic fibrosis. These results shed light on the mechanisms of fatty acid metabolic abnormalities in cystic fibrosis. They also have implications for the nutritional therapy of CF, highlighting the importance of specific fatty acid content, and in understanding the anti‐inflammatory effects of n‐3 fatty acids.
Hybrid mountain pass homoclinic solutions of a class of semilinear elliptic PDEs
Authors: Bolotin Sergey , Rabinowitz Paul H.
Published: February 2013

Variational gluing arguments are employed to construct new families of solutions for a class of semilinear elliptic PDEs. The main tools are the use of invariant regions for an associated heat flow and variational arguments. The latter provide a characterization of critical values of an associated functional. Among the novelties of the paper are the construction of “hybrid” solutions by gluing minima and mountain pass solutions and an analysis of the asymptotics of the gluing process.
HIV‐1 envelope trimer has similar binding characteristics for carbohydrate‐binding agents as monomeric gp120
Authors: Hoorelbeke Bart , van Montfort Thijs , Xue Jie , LiWang Patricia J. , Tanaka Haruo , Igarashi Yasuhiro , Van Damme Els J.M. , Sanders Rogier W. , Balzarini Jan
Published: February 2013

gp120
binds to
AH
by surface plasmon resonance (View Interaction: 1, 2)
Epidemiology of Brugada syndrome in Japan and rest of the world
Authors: Kamakura Shiro
Published: February 2013

Brugada syndrome is an inherited disease that causes sudden death because of ventricular fibrillation. Its prevalence is approximately 0.15% in adults and 0.005% in children in Asia, and less than 0.02% in the West. The reason for the higher prevalence in Asia is likely ethnic‐specific polymorphisms modulating the activity of the primary disease‐causing mutation. In Japan, the incidence of Brugada‐pattern electrocardiogram (ECG) is 14.2 per 100,000 person‐years. Data from multicenter registries indicate that its frequency in men with Brugada syndrome is higher in Japanese patients (94–96%) than in Caucasian patients (72–80%). Healthy individuals with Brugada‐type ECG have a favorable prognosis with an annual death rate of less than 0.5%.
Decentralized irrigation in China: An institutional analysis
Authors: Zhou Qian
Published: February 2013

Decentralized irrigation governance can improve irrigation, support water equity and reduce water conflicts. Decentralization, by changing actors’ incentives and encouraging farmers to engage in collective irrigation, can have positive outcomes. However, recent decentralization in developing countries has had mixed results including China. This paper examines empirical evidence from institutional analysis of two decentralized irrigation systems in central China, and finds that even following the same process of decentralization, access rights to water are not always equally distributed within the irrigation community and collective action does not always occur in every decentralized setting. Based on this, I argue that decentralization is not an end in itself. The assumption that local water users would automatically share decision-making rights, as long as these rights are transferred to localities, is wrong. It ignores the various considerations of physical conditions, interests of heterogeneity vs. homogeneity, and potential elite captures, which can influence or determine actors’ incentives and their behaviors.
Genetically obese mice do not show increased gut permeability or faecal bile acid hydrophobicity
Authors: Stenman Lotta K. , Holma Reetta , Gylling Helena , Korpela Riitta
Published: February 2013

Gut barrier dysfunction may lead to metabolic endotoxaemia and low-grade inflammation. Recent publications have demonstrated gut barrier dysfunction in obesity induced by a diet high in fat, and a pathogenetic role for luminal bile acids has been proposed. We aimed to investigate whether genetically obese mice develop increased gut permeability and alterations in luminal bile acids on a diet with a regular fat content. We used seven obese maleob/obmice of C57BL/6J background and ten male wild-type (WT) mice of the same strain. Faeces were collected for bile acid analysis. Intestinal permeability was measured in an Ussing chamber upon euthanasia, using 4 kDa fluorescein isothiocyanate dextran, as per mille (‰, 1/1000) of translocated dextran. We analysed the liver expression of lipopolysaccharide-binding protein (LBP), as well as serum LBP (ELISA). Intestinal permeability was not affected by genetic obesity (jejunum: 0·234 (sem0·04) ‰ for obesev. 0·225 (sem0·03) ‰ for WT,P= 0·93; colon: 0·222 (sem0·06) ‰ for obesev. 0·184 (sem0·03) ‰ for WT,P= 0·86), nor was liver LBP expression (relative expression: 0·55 (sem0·08) for obesev. 0·55 (sem0·13) for WT,P= 0·70). Serum LBP was 2·5-fold higher in obese than in WT mice (P= 0·001). Obese mice had increased daily excretion of total bile acids, but their faecal bile acid hydrophobicity was unchanged. In conclusion, genetic obesity did not impair gut barrier function in mice on a regular chow diet, nor was faecal bile acid hydrophobicity affected.
When Do Governments Resort to Election Violence?
Authors: Hafner-Burton Emilie M. , Hyde Susan D. , Jablonski Ryan S.
Published: February 2013

When are governments most likely to use election violence, and what factors can mitigate government incentives to resort to violence? How do the dynamics of election violence differ in the pre- and post-election periods? The central argument of this article is that an incumbent's fear of losing power as the result of an election, as well as institutionalized constraints on the incumbent's decision-making powers, are pivotal in her decision to use election violence. While it may seem obvious to suggest that incumbents use election violence in an effort to fend off threats to their power, it is not obvious how to gauge these threats. Thus, a central objective of this article is to identify sources of information about the incumbent's popularity that can help predict the likelihood of election violence. The observable implications of this argument are tested using newly available cross-national evidence on elections, government use of pre- and post-election violence, and post-election protests from 1981 to 2004.
Technology Competition and International Co-operation: Friends or Foes?
Authors: Kim Sung Eun , Urpelainen Johannes
Published: February 2013

Is technology competition between commercial rivals an impediment to international co-operation? Or could it instead help states collaborate? Our game-theoretic model suggests that technology competition impedes international co-operation when states hold ‘techno-nationalist’ preferences but have starkly asymmetric abilities to capture new markets. States that expect to lose refuse to co-operate, so treaty formation fails. However, technology competition may also facilitate co-operation. While states invest in new technologies out of self-interest, doing so also reduces consumer prices for other states. Comparative case studies of environmental co-operation demonstrate the model's utility. For example, European co-operation on climate policy was easier to achieve because forerunner countries, such as Denmark and Germany, implemented industrial policies that enhanced the competitiveness of their renewable energy industries. This technology competition reduced the cost of renewable energy for other European countries, and thus lowered the economic costs of their emissions reductions.
The importance of small-scale environment factors to community structure patterns of tropical rocky reef fish
Authors: Pinheiro Hudson T. , Martins Agnaldo S. , Joyeux Jean-Christophe
Published: February 2013

Understanding the spatial distribution of fish species and fish trophic guilds in reef environments may help improve our knowledge about ecological relationships and therefore favour sound strategies for sampling, coastal management and conservation policy. To verify if small-scale changes are important in forming the fish community structure at a tropical rocky coastal island, we assessed the depth, structural complexity and wave exposure gradients. The community structure changed along all gradients analysed. The trophic guilds found on the sheltered, low and intermediate exposure zones, in the deepest areas and in areas of highest structural complexity showed significant differences when compared with the general assemblage. Rocky reefs, even of narrow (transversal) extension, can show great changes in fish community structure at so small a scale that these changes are generally overlooked. The relationships evidenced between community and environment provide strong support for the importance of considering a wide array of such distinct environmental conditions when determining the structure patterns of the community.
Macrofauna inhabiting the spongeParaleucilla magna(Porifera: Calcarea) in Rio de Janeiro, Brazil
Authors: Padua André , Lanna Emilio , Klautau Michelle
Published: February 2013

Sponges (phylum Porifera) are important components of the benthic marine fauna known for their interactions with vertebrates and a large number of invertebrates seeking for food, shelter or substrate for attachment. Studies on this subject, however, were restricted only to the macrofauna inhabiting sponges of the class Demospongiae. In the present work, we describe the macrofauna associated with a calcareous sponge in Brazil,Paraleucilla magna. Individuals of this allegedly non-native species were monthly collected during one year in Rio de Janeiro (Brazil). Fifty-one taxa representing ten animal phyla were found associated withP. magna. The most frequent and abundant taxa were Crustacea, Mollusca, Polychaeta and Bryozoa, while echinoderms, cnidarians, ascidians, nemerteans, platyhelminthes and sponges were less frequent or even rare and less abundant. Juveniles of several taxa and pregnant females of Crustacea were found associated withP. magna, but these associations were not exclusive. The macrofauna associated withP. magnadid not present a clear seasonality, although it was possible to observe a change in the community composition alongside the year. The volume of the sponges was significantly related to the diversity index (H′) and number of taxa, but not with evenness (J′) and number of individuals. Our results show thatP. magnais used as a substrate for attachment and/or shelter by its associates and that most of these associations are just opportunistic. The data presented here reiterate a previous proposal that sponges are important biodiversity reservoirs and that they should be seriously considered in conservation programmes.
Antibacterial, antifungal and cytotoxic effects of a sea cucumberHolothuria leucospilota, from the north coast of the Persian Gulf
Authors: Mohammadizadeh Flora , Ehsanpor Maryam , Afkhami Majid , Mokhlesi Amin , Khazaali Aida , Montazeri Shohreh
Published: February 2013

Bioactive compounds of gonad, respiration tree, cuvierian organ, and body wall of the sea cucumberHolothuria leucospilotacollected from the north coast of the Persian Gulf were extracted using ethyl acetate, methanol and water–methanol solvents. Extracts were evaluated for their antibacterial and antifungal activities againstAspergillus niger,Candida albicans,Staphylococcus aureus,Pseudomonas aeruginosaandEscherichia coli. The activity was determined using the disc diffusion test. Cytotoxic activities of the extracts were determined by brine shrimp lethality assay. Results demonstrated that theA. nigerwas shown to be the most sensitive microorganism followed byC. albicans. The inhibition zone againstA. nigerandC. albicanshad minimum inhibitory concentrations ranging from 3 to 7 μg/ml. The highest antifungal activity was found in G (water–methanol) with an inhibition zone of 50 mm againstA. nigerat 18 μg/ml extract concentration continuing with CT (methanol) with 46 mm inhibition zone againstA. nigerat 18 μg/ml extract concentration. The highest cytotoxic effect of methanol extract was found with LC50values of about 40.31 μg/ml in the gonad organ fromH. leucospilotacontinuing with the respiration tree organ with LC50values of about 72.49 μg/ml.
Megafauna of the Charlie–Gibbs Fracture Zone (northern Mid-Atlantic Ridge) based on video observations
Authors: Gebruk A.V. , Krylova E.M.
Published: February 2013

Megafauna from the Charlie–Gibbs Fracture Zone (northern Mid-Atlantic Ridge) based on video observations from submersibles was analysed. Species composition was examined, frequency of species occurrence on the fracture wall and its base (depth range from 1740 m to 3100 m) and density of megafauna in the depression at the fracture zone bottom (4200–4500 m depth) were evaluated. At depths between 1700 and 2500 m hexactinellid sponges were most common and diverse. Deeper parts of the wall and its base were dominated by anthozoans (especially gorgonian corals) and echinoderms. A set of dominant species in the lower bathyal in the study area was different from that on the lower continental slope in the north-east Atlantic (Porcupine Seabight). An important contribution to local species richness of ‘rare’ species was demonstrated. The elpidiid holothurian, Kolga nana, occurred at high density in the abyssal depression.
The politics of immigrant policy in the 50 US states, 2005-2011
Authors: Monogan James E.
Published: February 2013

This article asks what shaped immigrant policy in the 50 states between 2005 and 2011. Theoretically, politicians are influenced by electoral considerations as they craft laws. Law-makers consider both current public opinion and how the electorate is likely to change, at least in the near future. Empirically, the article analyses an original dataset on immigrant-related laws enacted by the states with a Bayesian spatial conditionally autoregressive model. The analysis shows that state immigrant policy is affected primarily by legislative professionalism, electoral ideology, state wealth and change in the foreign-born population.
The second-language vocabulary trajectories of Turkish immigrant children in Norway from ages five to ten: the role of preschool talk exposure, maternal education, and co-ethnic concentration in the neighborhood
Authors: RYDLAND VESLEMØY , GRØVER VIBEKE , LAWRENCE JOSHUA
Published: February 2013

Little research has explored how preschools can support children's second-language (L2) vocabulary development. This study keenly followed the progress of twemty-six Turkish immigrant children growing up in Norway from preschool (age five) to fifth grade (age ten). Four different measures of preschool talk exposure (amount and diversity of teacher-led group talk and amount and diversity of peer talk), as well as the demographic variables of maternal education and co-ethnic concentration in the neighborhood, were employed to predict the children's L2 vocabulary trajectories. The results of growth analyses revealed that maternal education was the only variable predicting children's vocabulary growth during the elementary years. However, teacher-led talk, peer talk, and neighborhood predicted children's L2 vocabulary skills at age five, and these differences were maintained up to age ten. This study underscores the importance of both preschool talk exposure (teacher-led talk and peer talk) and demographic factors on L2 learners' vocabulary development.
Paid Companions: A Private Care Option for Older Adults
Authors: Outcalt Linda
Published: February 2013

Les compagnons rémunérés, fonctionnant d’une façon autonome ou par le biais des agences privées de soins à domicile, effectuent une variété de services pour les personnes âgées nanties qui peuvent se payer pour le soutien privé dans leurs maisons et dans les centres qui dispensent tels soins. Cette étude a examiné le travail accompli par les compagnons rémunérés, en s’appuyant sur des entretiens semi-structurés, ouverte, des entrevues en personne et d’élicitation des photos auto-pilotées (par lequel les individus prennent leur propres photos et en discuter plus tard dans les entretiens) avec 30 participants (15 compagnons, 8 clients et 7 informateurs clés). Les résultats ont révelé que, de plusieurs façons, les services fournis par les compagnons pour les clients qui vivent dans leurs propres maisons ressemblent aux soins à domicile basés sur les tâches, mais l’accent mis sur le travail est différent. Les relations sociales et émotionelles avec les clients sont au centre de leur travail. Les compagnons basés dans les établissements jouent un rôle unique, remplissant le vide laissé par les compressions budgetaires des ratios de dotation en personnel, qui garde les résidents âgés, souvent atteint de démence, impliqués et engagés dans le monde.
MicroRNAs: a new piece in the paediatric cardiovascular disease puzzle
Authors: Omran Ahmed , Elimam Dalia , Webster Keith A. , Shehadeh Lina A. , Yin Fei
Published: February 2013

Cardiovascular diseases in children comprise a large public health problem. The major goals of paediatric cardiologists and paediatric cardiovascular researchers are to identify the cause(s) of these diseases to improve treatment and preventive protocols. Recent studies show the involvement of microRNAs (miRs) in different aspects of heart development, function, and disease. Therefore, miR-based research in paediatric cardiovascular disorders is crucial for a better understanding of the underlying pathogenesis of the disease, and unravelling novel, efficient, preventive, and therapeutic means. The ultimate goal of such research is to secure normal cardiac development and hence decrease disabilities, improve clinical outcomes, and decrease the morbidity and mortality among children. This review focuses on the role of miRs in different paediatric cardiovascular conditions in an effort to encourage miR-based research in paediatric cardiovascular disorders.
Assessing Social Cognition and Pragmatic Language in Adolescents with Traumatic Brain Injuries
Authors: McDonald Skye , English Therese , Randall Rebekah , Longman Thea , Togher Leanne , Tate Robyn L.
Published: February 2013

Traumatic brain injuries (TBI) in children and adolescents can impair social cognition and communication skills but there are few assessment tools suitable for adolescents. The Awareness of Social Inference Test (TASIT) uses professionally enacted audiovisual vignettes of everyday conversational exchanges and is a valid measure of social perception disorders in adults. This study examined its utility for assessing impairments in social cognition in a group of 16 adolescents with TBI, compared to a group of 16 typically developing (TD) adolescents. Adolescents with TBI were, on average, no different to their TD peers on TASIT 1 (emotion recognition) and TASIT 3 (recognizing lies and sarcasm when provided with additional cues) but performed more poorly on TASIT 2 which required them to interpret sarcastic and sincere conversational exchanges with few cues other than the demeanor of the speakers. Within the TBI group, poor performance on TASIT correlated to both relative and self-reported communication difficulties at home. It also correlated with IQ, face recognition and severity of injury as indexed by duration of post-traumatic amnesia. Overall, this study suggests TASIT is a valid measure for adolescents although it raised questions as to how effective normative data is for comparing performance in social cognition during childhood and adolescence. (JINS, 2013,19, 1–11)
Environmental Scanning Electron Microscopy Technique to Identify Asbestos Phases Inside Ferruginous Bodies
Authors: Croce Alessandro , Musa Maya , Allegrina Mario , Trivero Paolo , Rinaudo Caterina
Published: February 2013

Ferruginous bodies observed in lungs of patients affected by mesothelioma, asbestosis, and pulmonary carcinoma are important to relate the illness to exposure, environmental or occupational, to asbestos. Identification of the inorganic phase constituting the core of the ferruginous bodies, formed around asbestos but also around phases different from asbestos, is essential for legal purposes. Environmental scanning electron microscopy/energy dispersive spectroscopy was used to identify the fibrous mineral phase in the core of ferruginous bodies observed directly in thin sections of tissue, without digestion of the biological matrix. Spectra were taken with sequential analyses along a line crossing the core of the ferruginous bodies. By comparing the spectra taken near to and far from the core, the chemical elements that make up the core could be identified.
The cosmic distance scale and H0: Past, present, and future
Authors: Freedman Wendy L.
Published: February 2013

Twenty years ago, there was disagreement at a level of a factor of two as regards the value of the expansion rate of the Universe. Ten years ago, a value that was good to 10% was established using the Hubble Space Telescope (HST), completing one of the primary missions that NASA designed and built the HST to undertake. Today, after confronting most of the systematic uncertainties listed at the end of the Key Project, we are looking at a value of the Hubble constant that is plausibly known to within 3%. In the near future, an independently determined value of H0 good to 1% is desirable to constrain the extraction of other cosmological parameters from the power spectrum of the cosmic microwave background in defining a concordance model of cosmology. We review recent progress and assess the future prospects for those tighter constraints on the Hubble constant, which were unimaginable just a decade ago.
Allan Sandage and the distance scale
Authors: Tammann G. A. , Reindl B.
Published: February 2013

Allan Sandage returned to the distance scale and the calibration of the Hubble constant again and again during his active life, experimenting with different distance indicators. In 1952 his proof of the high luminosity of Cepheids confirmed Baade's revision of the distance scale (H0 ~ 250 km s−1 Mpc−1). During the next 25 years, he lowered the value to 75 and 55. Upon the arrival of the Hubble Space Telescope, he observed Cepheids to calibrate the mean luminosity of nearby Type Ia supernovae (SNe Ia) which, used as standard candles, led to the cosmic value of H0 = 62.3 ± 1.3 ± 5.0 km s−1 Mpc−1. Eventually he turned to the tip of the red giant branch (TRGB) as a very powerful distance indicator. A compilation of 176 TRGB distances yielded a mean, very local value of H0 = 62.9 ± 1.6 km s−1 Mpc−1 and shed light on the streaming velocities in the Local Supercluster. Moreover, TRGB distances are now available for six SNe Ia; if their mean luminosity is applied to distant SNe Ia, one obtains H0 = 64.6 ± 1.6 ± 2.0 km s−1 Mpc−1. The weighted mean of the two independent large-scale calibrations yields H0 = 64.1 km s−1 Mpc−1 within 3.6%.
The effects of physics and chemical-abundance uncertainties on the properties of lower-mass stars that are used as standard candles
Authors: VandenBerg Don A.
Published: February 2013

The distances to old stellar populations have traditionally been derived from three standard candles: the luminosity of the red-giant-branch tip, the absolute magnitudes of RR Lyrae stars, and the colour–magnitude-diagram loci of nearby subdwarfs. The distance-modulus uncertainties that are associated with these methods are still at the level of ±0.10–0.15 mag. Current stellar models are able to satisfy these age-independent constraints to well within their error bars, which are mainly owing to the uncertainties in the distances of the calibrating objects and, directly or indirectly, to chemical-abundance uncertainties. The impact of varying the physics and the assumed abundances in stellar models on the aforementioned standard candles is discussed, as is the use of the giant-branch bump luminosity to constrain the distance scale.
Toward improving the accuracy of Cepheid distances through parallax of pulsation
Authors: Mérand Antoine , Kervella Pierre , Aufdenberg Jason P. , Gallenne Alexandre
Published: February 2013

Improvement of the calibration of the Cepheid period–luminosity relation (Leavitt's Law) is one of the main challenges to improve the accuracy of the Hubble constant, H0. Many parallax-of-pulsation methods are promising but have not yet delivered sufficiently accurate distances: observational biases, such as the projection factor, still dominate. We propose a global parallax-of-pulsation method, combining all observables (photometry, spectroscopy, and interferometry), to (i) reduce statistical errors, (ii) use the redundancy among observables to validate our approach, and (iii) achieve 2% accuracy for individual Cepheid distances.
The Baade–Becker–Wesselink technique and the fundamental astrophysical parameters of Cepheids
Authors: Rastorguev Alexey S. , Dambis Andrey K. , Zabolotskikh Marina V. , Berdnikov Leonid N. , Gorynya Natalia A.
Published: February 2013

The Baade–Becker–Wesselink (BBW) method remains one of most often used tools to derive a full set of Cepheid astrophysical parameters. The surface brightness version of the BBW technique was preferentially used during the past few decades to calculate Cepheid radii and to improve period–luminosity–colour relations. Its implementation requires a priori knowledge of Cepheid reddening values. We propose a new version of the BBW technique, which allows one to independently determine the colour excess and the intrinsic colour of a radially pulsating star, in addition to its radius, luminosity and distance. The new technique is a generalization of the Balona light curve-modelling approach. The method also allows calibration of the function F(CI0) = BC(CI0) + 10 log [Teff (CI0)] for the class of pulsating stars considered. We apply this technique to a number of classical Cepheids with very accurate light and radial-velocity curves. The new technique can also be applied to other pulsating variables, e.g., RR Lyrae stars. We also discuss the possible dependence of the projection factor on the pulsation phase.
The distance to the Small Magellanic Cloud from eclipsing binaries
Authors: Graczyk Dariusz , Pietrzyński Grzegorz , Pilecki Bogumił , Thompson Ian B. , Gieren Wolfgang , Konorski Piotr , Udalski Andrzej , Soszyński Igor
Published: February 2013

A preliminary distance etimate to SMC 108.1.14904, a long-period eclipsing binary in the Small Magellanic Cloud, is presented. The binary system contains two bright, non-active G-type giants. Its orbital period is 185 days and the orbit is circular. Using surface brightness calibration, we obtain a distance modulus to the system of (m-M)= 19.02 ± 0.04 (statistical) ± 0.05 (systematic) mag, where the systematic error is dominated by uncertainties in the surface brightness calibration. This is a second eclipsing binary in the SMC analysed by our team.
Application of the Direct Distance Estimation procedure to eclipsing binaries in star clusters
Authors: Milone E. F. , Schiller S. J.
Published: February 2013

We alert the community to a paradigm method to calibrate a range of standard candles by means of well-calibrated photometry of eclipsing binaries in star clusters. In particular, we re-examine systems studied as part of our Binaries-in-Clusters program, and previously analyzed with earlier versions of the Wilson–Devinney light-curve modeling program. We make use of the 2010 version of this program, which incorporates a procedure to estimate the distance to an eclipsing system directly, as a system parameter, and is thus dependent on the data and analysis model alone. As such, the derived distance is accorded a standard error, independent of any additional assumptions or approximations that such analyses conventionally require.
The planetary nebula luminosity function
Authors: Ciardullo Robin
Published: February 2013

Although the method has no theoretical explanation, the [Oiii]λ5007Å planetary nebula luminosity function (PNLF) is an extremely valuable tool for obtaining accurate (< 10%) extragalactic distances out to ~ 18 Mpc. Because the PNLF works in large galaxies of all Hubble types, it is one of the best tools we have for cross-checking the results of other methods and identifying systematic offsets between the Population I and Population II distance ladders. We review the PNLF's calibration and show that the method's Cepheid-derived zero point is virtually identical to that inferred from measurements of the tip of the red giant branch. We then compare the PNLF to the surface brightness fluctuations method and demonstrate that the latter's calibration yields a distance scale that is ~ 15% larger than that of the PNLF. We argue that this offset is likely due to a number of factors, including the effects of reddening on both of the techniques. We conclude by discussing the use of the PNLF for supernovae Type Ia calibration and considering the outstanding problems associated with the method.
The 6dFGS peculiar velocity field
Authors: Springob Christopher M. , Magoulas Christina , Colless Matthew , Jones D. Heath , Campbell Lachlan , Lucey John , Mould Jeremy , Erdoğdu Pirin
Published: February 2013

The 6dF Galaxy Survey (6dFGS) is an all-southern-sky galaxy survey, including 125,000 redshifts and a Fundamental Plane (FP) subsample of 10,000 peculiar velocities. This makes 6dFGS the largest peculiar-velocity sample to date. We have fitted the FP with a tri-variate Gaussian model using a maximum-likelihood approach, and derive the Bayesian probability distribution of the peculiar velocity for each of the 10,000 galaxies. We fit models of the velocity field, including comparisons to the field predicted from the redshift-survey density field, to derive the values of the redshift-space distortion parameter β, the bulk flow and the residual bulk flow in excess of that predicted from the density field. We compare these results to those derived by other authors and discuss the cosmological implications.
Testing the distance-duality relation to probe the morphology of galaxy clusters
Authors: Meng Xiao-Lei
Published: February 2013

Aiming at comparing different morphological models of galaxy clusters, we use two new methods to construct a cosmological-model-independent test of the distance-duality (DD) relation. The luminosity distances come from the Union2 compilation of Type Ia supernovae. The angular-diameter distances are given by the two cluster models of De Filippis et al. and Bonamente et al. The advantage of our new methods is that they can lead to reduced statistical errors. The morphologies of the cluster models are mainly focused on a comparison between the elliptical and spherical β models. The spherical β model is divided into two groups, in terms of different reduction methods of angular-diameter distances, i.e. the conservative and corrected spherical β models. Our results show that the DD relation is consistent with the elliptical β model at the 1σ confidence level (CL) for both methods, whereas for almost all spherical β-model parameterizations the DD relation can only be accommodated at the 3σ CL, particularly for the conservative spherical β model. To minimize systematic uncertainties, we also apply the test to the overlap sample, i.e. to the same set of clusters modeled by both De Filippis et al. and Bonamente et al. The DD relation is compatible with the elliptically modeled overlap sample at the 1σ CL; however, for most parameterizations the DD relation cannot be accommodated even at the 3σ CL by any of the two spherical β models. Therefore, it is reasonable that the marked triaxial ellipsoidal model is a better geometric hypothesis describing the structure of galaxy clusters than the spherical β model if the DD relation is valid for cosmological observations.
Revisiting the absolute-magnitude calibration of F-type supergiants and bright giants as a function of the equivalent width of the OIλ7774Å triplet
Authors: Dambis A. K.
Published: February 2013

We reduce the published measurements of the equivalent width of the oxygen triplet (Oiλ7774Å) to a single system and combine the resulting homogenized indices with revised Hipparcos parallaxes to derive the MK versus log[W(Oiλ7774Å)] absolute-magnitude calibration for bright F-type giants and supergiants and use the resulting calibration to estimate both the distance to the Large Magellanic Cloud and the parameters of the Galactic rotation curve.
Determination of the fundamental properties of an M31 globular cluster from main-sequence photometry
Authors: Ma Jun
Published: February 2013

We determined the age of the M31 globular cluster B379 using isochrones of the Padova stellar evolutionary models. At the same time, the cluster's metal abundance, its distance modulus, and reddening value were also obtained. The results obtained in this paper are consistent with previous determinations, including the age. Brown et al. constrained the age of B379 by comparing its color–magnitude diagram with isochrones of the 2006 VandenBerg models. Therefore, this paper confirms the consistency of the age scale of B379 between the Padova isochrones and the 2006 VandenBerg isochrones. The results of B379 obtained in this paper are: metallicity [M/H] = log(Z/Z⊙) = −0.325 dex, age τ = 11.0 ± 1.5 Gyr, reddening E(B − V) = 0.08 mag, and distance modulus (m − M)0 = 24.44 ± 0.10 mag. Using the metallicity, the reddening value and the distance modulus obtained in this paper, we constrained the age of B379 by comparing its multicolor photometry with theoretical stellar population synthesis models. The age of B379 obtained is 10.6−0.76+0.92 Gyr, which is in very good agreement with the determination from main-sequence photometry.
Improving distance estimates to nearby bright stars: Combining astrometric data from Hipparcos, Nano-JASMINE and Gaia
Authors: Michalik Daniel , Lindegren Lennart , Hobbs David , Lammers Uwe , Yamada Yoshiyuki
Published: February 2013

Starting in 2013, Gaia will deliver highly accurate astrometric data, which eventually will supersede most other stellar catalogues in accuracy and completeness. It is, however, limited to observations from magnitude 6 to 20 and will therefore not include the brightest stars. Nano-JASMINE, an ultrasmall Japanese astrometry satellite, will observe these bright stars, but with much lower accuracy. Hence, the Hipparcos catalogue from 1997 will likely remain the main source of accurate distances to bright nearby stars. We are investigating how this might be improved by optimally combining data from all three missions through a joint astrometric solution. This would take advantage of the unique features of each mission: the historic bright-star measurements of Hipparcos, the updated bright-star observations of Nano-JASMINE, and the very accurate reference frame of Gaia. The long temporal baseline between the missions provides additional benefits for the determination of proper motions and binary detection, which indirectly improve the parallax determination further. We present a quantitative analysis of the expected gains based on simulated data for all three missions.
The kinematics and chemistry of the Sagittarius streams
Authors: Shi Weibin , Chen Yuqin , Carrell Kenneth , Zhao Gang
Published: February 2013

We selected red horizontal-branch stars along the streams of the Sagittarius dwarf galaxy (Sgr) from sdss DR7 spectroscopic data using a theoretical model. We investigate the metallicity distribution of stars in the Sgr streams. The metallicity gradient is (−1.8 ± 0.3) × 10⊃3 dex deg−1 in the first wrap of the trailing arm and (−1.5 ± 0.4) × 10−3 dex deg−1 in the first wrap of the leading arm.
A preliminary systematic search for red-clump stars in Galactic open clusters based on 2mass data
Authors: Zhang Xi , Chen Li , Li Zhongmu
Published: February 2013

Red-clump (RC) giants are intermediate-age, core-helium-burning stars. The RC can be used as a standard candle. In particular, the small variance of the RC's K-band intrinsic luminosity and its weak dependence on chemical composition and age make it an extremely useful distance indicator. In this paper, we use 2mass data to search for RC stars in a sample of 60 Galactic open clusters with known reddening, ages, and distances, and obtain an average value for the RC's absolute Ks-band magnitude, MKs = −1.72 ± 0.17 mag.
Swift Trust in Global Virtual Teams
Authors: Crisp C. Brad , Jarvenpaa Sirkka L.
Published: February 2013

Ad hoc global virtual teams are associated with swift trust – a unique form of trust in temporary systems. Cognitive components of swift trust render it fragile and in need of reinforcement and calibration by actions. Action components of swift trust are undertheorized as are the links to team performance. We elaborate on the normative action processes of swift trust and their relationship to performance, and then report results from a longitudinal quasi-experimental study of 68 temporary virtual teams with no face-to-face interaction. Results provide support for our theory about how the normative action processes involve setting and monitoring performance norms that are supported by early trusting beliefs and that increase late trusting beliefs and consequently team performance in virtual teams.
Emergence of Differing Electronic Communication Norms Within Partially Distributed Teams
Authors: Cheshin Arik , Kim Yongsuk , Bos Nathan D. , Ning Nan , Olson Judith S.
Published: February 2013

Modern organizations often consist of teams in which some people are collocated and some are remote. These teams are in-between being entirely virtual to entirely face-to-face and are referred to as partially distributed teams. Partially distributed teams function and operate in two different media environments, varying in availability of communication channels. These media environments may encourage different communication patterns, widening a gap produced by distance. In two laboratory studies we demonstrate that different electronic communication norms (ECNs) emerge among members of the same team based on their media environments. Most of the norms regarding use of electronic communication persisted even when media environment was changed. This difference in ECNs might serve as an additional faultline, causing an additional rift within distributed teams.
Reversible Covalent Bond Formation as a Strategy for Healable Polymer Networks
Authors: Kloxin Christopher J.
Published: February 2013

This chapter outlines several critical aspects of the design of polymer networks containing reversible covalent cross-links for material healing applications. Polymer network architecture and reversible cross-link type are identified as the principle considerations in covalent adaptable network design, as they ultimately dictate how efficiently the material will heal or relax on a macroscopic length-scale. Additionally, several reversible addition- and exchange-type covalent chemistries suitable as cross-links in covalent adaptable networks, as well as strategies to trigger healing reactions, are highlighted. Finally, the dynamic properties of these materials is briefly discussed, highlighting the distinguishing characteristics in comparison with traditional thermoplastics and thermosets.
Validation and Application of QuEChERS to Flavor and Fragrance R&D
Authors: Harmuth N. , Fang F. , Reiner G.
Published: February 2013

In the flavor industry many R&D analysis requests are for the quantification of flavor components in a sample. This is generally accomplished by liquid-liquid extraction, typically using solvents such as methylene chloride or toluene. The extraction of these samples is time consuming, as it generally takes over an hour. Complex matrices impose an even greater challenge due to their varying water solubility properties and matrix interferences. The extraction of flavor compounds from these matrices often requires multi-step extractions, which increases the chance of flavor loss, particularly of the highly-volatile compounds. The official AOAC QuEChERS method has been modified to address these obstacles; this paper highlights the method development and results of the study. The modified QuEChERS method has drastically decreased the extraction time, thus increasing sample throughput capacity. This benefit is highly valued in today's R&D laboratory enviroment.
Effect of Enzyme Treatment on Volatile Profile of White and Red Wines from Macedonia by using HS-SPME-GC/MS
Authors: Kostadinović Veličkovska Sanja , Tolle Sebastian , Goek Recep , Milanov Goran , Winterhalter Peter
Published: February 2013

The flavor of white wines is due to a complex mixture of many volatile compounds. These compounds have distinct physicochemical properties regarding, for example, polarity, volatility and odour impact. In this study, for isolation of free and glycosidically-bond volatile compounds, a head space solid-phase microextraction (HS-SPME) procedure was applied for sample preparation of white and red wines from Macedonia followed by separation and identification with GC-MS. Separation of the compounds was performed on a Carbowax column after the injection of the CRB-DVB-PDMS fiber in splitless mode. The liberation of the glycosidically-bond volatiles was perform by application of enzyme “Endozyme Aromatic” for “Temjanika” and “AR 2000” for the rest of examined wines. The main gropes of volatile compounds in Temjanika and Muscat wines produced from Muscat de Frontignan grape variety were terpenes especially limonene, p-cymene, linalool, gernaiol, citronellol and for other wines produced from red grape variety such as Vranec and Merlot, the most abundant compounds were alcohols, esters and fatty acids. Statistical analyses confirmed that the effect of enzymatic treatment for the examined wines was more significant than the varieties of grapes from which the wines were produced.
Aroma Character of Coriander (Coriandrum Sativum L.) Leaves: Limited Odor Unit Method and Sensory Perception in Preference
Authors: Tamura H. , Maeyama K. , Yoshida E. , Kori M.
Published: February 2013

Coriander aroma from Coriandrum sativum L. leaves, having a strong oriental scent was characterized by using limited odor unit (Lod) and sensory perception in preference. Forty-two volatile compounds from the coriander extracts collected by modified solvent extracts were identified by GC/MS and retention indices. (E)-2-Tetradecenal was a major component (40.6% of the total oil). Odor thresholds for 42 compounds identified in this oil were determined by organoleptic manner using two out of five tests and then Lod values are calculated from the odor thresholds and individual concentrations. Finally, as sensory test of different concentrations of coriander oils indicated that the most preferable concentration of coriander leave oil for human perception was between 1000 ppm and 60 ppm, Lod analyses at 1000 ppm and 60 ppm should, therefore, reveal important chemicals that contribute to the critical judgment of assessors in preference.