bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cash Flow and Discount Rate Risk in Up and Down Markets: What Is Actually Priced?
Authors: Botshekan Mahmoud , Kraeussl Roman , Lucas Andre 
Published: October 2012

AbstractWe test whether asymmetric preferences for losses versus gains affect the prices of cash flow versus discount rate risk. We construct a return decomposition distinguishing cash flow and discount rate betas in up and down markets. Using U.S. data, we find that downside cash flow and discount rate betas carry the largest premia. Downside cash flow risk is priced consistently across different samples, periods, and return decomposition methods. It is the only component of beta with significant out-of-sample predictive ability. Downside cash flow premia mainly occur for small stocks, while large stocks are compensated for symmetric cash-flow-related risk.
Helminth parasite communities of allopatric populations of the frog Leptodactylus podicipinus from Pantanal, Brazil
Authors: Campião K.M. , da Silva R.J. , Ferreira V.L. 
Published: October 2012

AbstractSeveral factors may influence the structure of parasite communities in amphibian hosts. In this study, we describe the helminth parasites of three allopatric populations of the frog Leptodactylus podicipinus and test whether host size and sex were determinants of the structure and composition of the helminth communities. One hundred and twenty-three anurans were collected from three different study sites within the Pantanal wetlands and surveyed for helminth parasites. We found 14 helminth taxa: 7 species of nematodes, 4 species of trematodes, 1 species of cestodes, 1 species of acanthocephalan and one unidentified cyst. Host sex and size did not cause significant differences in helminth abundance or richness. The structure of helminth communities from the three study sites varied in terms of species composition, abundance and diversity. Six out of 14 helminth taxa were found in the three localities. Among those, the nematodes Cosmocerca podicipinus and Rhabdias sp., the trematode Catadiscus propinquus and the helminth cyst showed significant differences in mean abundances. We suggest that such differences found among the three component communities are driven by biotic and abiotic factors operating locally. Moreover, these differences stress the importance of local conditions, such as hydrologic characteristics and landscape composition, on helminth community structure.
A Novel Analytical Framework for Dynamic Quaternion Ship Domains
Authors: Wang Ning 
Published: October 2012

In this paper, a novel analytical framework for Dynamic Quaternion Ship Domain (DQSD) models has been initially proposed via the Quaternion Ship Domain (QSD) model structure. Unlike previous ship domains, the proposed DQSD model is able to capture essential subjectivity and objectivity of ship domains. To be specific, the significant characteristics are as follows:
(1)The proposed DQSD model is integrated by three independent submodels of ship, human and circumstance, which are determined by ship manoeuvrability, navigator's states, and navigation circumstance, respectively.(2)The ship manoeuvrability derived from the MMG-type ship motion model is employed to establish the ship submodel which identifies the DQSD scale.(3)A novel navigator reliability model is proposed to realize the human submodel which defines the ship domain shape with navigator ability, physical and mental states being input variables.(4)In addition, visibility, wind force, wave and traffic congestion are incorporated into the circumstance submodel which is employed to zoom in or out of the DQSD-type ship domain.Finally, the well-known Esso Osaka tanker model is used to conduct simulation studies on various typical stationary and dynamic situations, and comparative investigations with each other have been comprehensively analysed. Simulation results demonstrate that the DQSD model can capture critical dynamics of ship domains and undoubtedly be effective and superior to previous ship domains in terms of performance and accuracy.
Chronic Postconcussion Symptoms and Functional Outcomes in OEF/OIF Veterans with Self-Report of Blast Exposure
Authors: Verfaellie Mieke , Lafleche Ginette , Spiro Avron , Tun Carlos , Bousquet Kathryn 
Published: October 2012

AbstractPostconcussion symptoms (PCS) and functional outcomes were evaluated in 91 OEF/OIF outpatient veterans with reported histories of blast-exposure, with the goal of evaluating (1) the association between these outcomes and a clinical diagnosis of mild traumatic brain injury (mTBI) with or without loss of consciousness (LOC); and (2) the influence of post-traumatic stress disorder (PTSD) and depression on PCS reporting and perceived functional limitations. Individuals who reported mTBI with LOC had greater PCS complaints than individuals who reported mTBI without LOC or individuals without mTBI. However, after adjusting for severity of PTSD and depression symptoms, this group difference disappeared. Functional limitations were particularly prominent in the psychosocial domain. Again, PTSD was significantly associated with functional outcomes, but the mTBI with LOC group had greater psychosocial limitations than the other two groups, even when PTSD and depression symptoms were taken into account. These findings highlight the role of mental health in both outcomes, but additionally point to the impact of mTBI with LOC on long-term psychosocial adjustment. (JINS, 2013, 19, 1–10)
Egocentric and Allocentric Spatial Representations in Williams Syndrome
Authors: Bernardino Inês , Mouga Susana , Castelo-Branco Miguel , van Asselen Marieke 
Published: October 2012

AbstractWilliams syndrome (WS) is a neurodevelopmental disorder characterized by severe visuospatial deficits, particularly affecting spatial navigation and wayfinding. Creating egocentric (viewer-dependent) and allocentric (viewer-independent) representations of space is essential for the development of these abilities. However, it remains unclear whether egocentric and allocentric representations are impaired in WS. In this study, we investigate egocentric and allocentric frames of reference in this disorder. A WS group (n = 18), as well as a chronological age-matched control group (n = 20), a non-verbal mental age-matched control group (n = 20) and a control group with intellectual disability (n = 17), was tested with a computerized and a 3D spatial judgment task. The results showed that WS participants are impaired when performing both egocentric and allocentric spatial judgments even when compared with mental age-matched control participants. This indicates that a substantial deficit affecting both spatial representations is present in WS. The egocentric impairment is in line with the dorsal visual pathway deficit previously reported in WS. Interestingly, the difficulties found in performing allocentric spatial judgments give important cues to better understand the ventral visual functioning in WS. (JINS, 2013, 19, 1–9)
Disassembling Glancing Angle Deposited Films for High-Throughput, Single-Post Growth Scaling Measurements
Authors: Siewert Joshua Morgan Arthur , LaForge Joshua Michael , Taschuk Michael Thomas , Brett Michael Julian 
Published: October 2012

AbstractWith growing interest in nanostructured thin films produced by glancing angle deposition (GLAD), it becomes increasingly important to understand their overall growth mechanics and nanocolumn structure. We present a new method of isolating the individual nanocolumns of GLAD films, facilitating automated measurement of their broadening profiles. Data collected for α = 81° TiO2 vertical nanocolumns deposited across a range of substrate rotation rates demonstrates that these rates influence growth scaling parameters. Further, individual posts were found in each case that violate predicted Kardar-Parisi-Zhang growth scaling limits. The technique's current iteration is comparable to existing techniques in speed: though data were studied from 10,756 individual objects, the majority could not be confidently used in subsequent analysis. Further refinement may allow high-throughput automated film characterization and permit close examination of subtle growth trends, potentially enhancing control over GLAD film broadening and morphology.
Atom Probe Tomography Simulations and Density Functional Theory Calculations of Bonding Energies in Cu3Au
Authors: Boll Torben , Zhu Zhi-Yong , Al-Kassab Talaat , Schwingenschlögl Udo 
Published: October 2012

AbstractIn this article the Cu-Au binding energy in Cu3Au is determined by comparing experimental atom probe tomography (APT) results to simulations. The resulting bonding energy is supported by density functional theory calculations. The APT simulations are based on the Müller-Schottky equation, which is modified to include different atomic neighborhoods and their characteristic bonds. The local environment is considered up to the fifth next nearest neighbors. To compare the experimental with simulated APT data, the AtomVicinity algorithm, which provides statistical information about the positions of the neighboring atoms, is applied. The quality of this information is influenced by the field evaporation behavior of the different species, which is connected to the bonding energies.
Micro Energy-Dispersive X-Ray Fluoresence Mapping of Enamel and Dental Materials after Chemical Erosion
Authors: Soares Luís Eduardo Silva , de Oliveira Rodrigo , Nahórny Sídnei , Santo Ana Maria do Espírito , Martin Airton Abrahão 
Published: October 2012

AbstractEnergy-dispersive X-ray fluorescence was employed to test the hypothesis that beverage consumption or mouthwash utilization will change the chemical properties of dental materials and enamel mineral content. Bovine enamel samples (n= 45) each received two cavity preparations (n= 90), each pair filled with one of three dental materials (R: nanofilled composite resin; GIC: glass-ionomer cement; RMGIC: resin-modified GIC). Furthermore, they were treated with three different solutions (S: saliva; E: erosion/Pepsi Twist®; or EM: erosion+mouthwash/Colgate Plax®). It was found that mineral loss in enamel was greater in GICE samples than in RE > RMGICE > RMGICEM > REM > GICEM. An increased percentage of Zr was found in REM indicating organic matrix degradation. Dental materials tested (R, GIC, and RMGIC) were not able to protect adjacent enamel from acid erosion by the soft drink tested. The use of mouthwash promoted protection of enamel after erosion by the soft drink. To avoid chemical dissolution by mouthwashes, protection by resin composites with surface sealants is recommended.
The Ionian Sea: The oldest in situ ocean fragment of the world?
Authors: Speranza Fabio , Minelli Liliana , Pignatelli Alessandro , Chiappini Massimo 
Published: October 2012

It is well known that the Ionian Sea is characterized by thin (8–11 km) crystalline crust, thick (5–7 km) sedimentary cover, and low heat flow, typical for a Mesozoic (at least) basin. Yet seismic data have not yielded univocal interpretations, and a debate has developed on the oceanic versus “thinned continental” nature of the Ionian basin. Here we analyze the magnetic anomaly pattern of the Ionian Sea and compare it to synthetic fields produced by a geopotential field generator, considering realistic crust geometry. The Ionian basin is mostly characterized by slightly negative magnetic residuals and by a prominent positive (150 nT at sea level) “B” anomaly at the northwestern basin margin. We first test continental crust models, considering a homogeneous crystalline crust with K = 1 × 10−3, then a 5 km thick deep crustal layer of serpentinite (K = 1 × 10−1). The first model yields insignificant anomalies, while the second gives an anomaly pattern anticorrelated with the observed residuals. We subsequently test oceanic crust models, considering a 2 km thick 2A basaltic layer with K = 5 × 10−3, magnetic remanence of 5 A/m, and a unique magnetic polarity (no typical oceanic magnetic anomaly stripes are apparent in the observed data set). Magnetic remanence directions were derived from Pangean‐African paleopoles in the 290–190 Ma age window. Only reverse polarity models reproduce the B anomaly, and among them the 220–230 Ma models best approximate magnetic features observed on the abyssal plain and at the western basin boundary. The Ionian Sea turns out to be the oldest preserved oceanic floor known so far.
Simulating the thermochemical magmatic and tectonic evolution of Venus's mantle and lithosphere: Two‐dimensional models
Authors: Armann Marina , Tackley Paul J. 
Published: October 2012

Numerical convection models of the thermochemical evolution of Venus are compared to present‐day topography and geoid and recent resurfacing history. The models include melting, magmatism, decaying heat‐producing elements, core cooling, realistic temperature‐dependent viscosity and either stagnant lid or episodic lithospheric overturn. In stagnant lid convection the dominant mode of heat loss is magmatic heat pipe, which requires massive magmatism and produces very thick crust, inconsistent with observations. Partitioning of heat‐producing elements into the crust helps but does not help enough. Episodic lid overturn interspersed by periods of quiescence effectively loses Venus's heat while giving lower rates of volcanism and a thinner crust. Calculations predict 5–8 overturn events over Venus's history, each lasting ∼150 Myr, initiating in one place and then spreading globally. During quiescent periods convection keeps the lithosphere thin. Magmatism keeps the mantle temperature ∼constant over Venus's history. Crustal recycling occurs by entrainment in stagnant lid convection, and by lid overturn in episodic mode. Venus‐like amplitudes of topography and geoid can be produced in either stagnant or episodic modes, with a viscosity profile that is Earth‐like but shifted to higher values. The basalt density inversion below the olivine‐perovskite transition causes compositional stratification around 730 km; breakdown of this layering increases episodicity but far less than episodic lid overturn. The classical stagnant lid mode with interior temperature ∼rheological temperature scale lower than TCMBis not reached because mantle temperature is controlled by magmatism while the core cools slowly from a superheated start. Core heat flow decreases with time, possibly shutting off the dynamo, particularly in episodic cases.
Antagonism influences assembly of a Bacillus guild in a local community and is depicted as a food-chain network
Authors: Pérez-Gutiérrez Rocío-Anaís , López-Ramírez Varinia , Islas África , Alcaraz Luis David , Hernández-González Ismael , Olivera Beatriz Carely Luna , Santillán Moisés , Eguiarte Luis E , Souza Valeria , Travisano Michael , Olmedo-Alvarez Gabriela 
Published: October 2012

Abstract
Understanding the principles that govern community assemblages is a central goal of ecology. There is limited experimental evidence in natural settings showing that microbial assembly in communities are influenced by antagonistic interactions. We, therefore, analyzed antagonism among bacterial isolates from a taxonomically related bacterial guild obtained from five sites in sediments from a fresh water system. We hypothesized that if antagonistic interactions acted as a shaping force of the community assembly, then the frequency of resistance to antagonism among bacterial isolates originating from a given site would be higher than the resistance to conspecifics originating from a different assemblage. Antagonism assays were conducted between 78 thermoresistant isolates, of which 72 were Bacillus spp. Sensitive, resistant and antagonistic isolates co-occurred at each site, but the within-site frequency of resistance observed was higher than that observed when assessed across-sites. We found that antagonism results from bacteriocin-like substances aimed at the exclusion of conspecifics. More than 6000 interactions were scored and described by a directed network with hierarchical structure that exhibited properties that resembled a food chain, where the different Bacillus taxonomic groups occupied specific positions. For some tested interacting pairs, the unidirectional interaction could be explained by competition that inhibited growth or completely excluded one of the pair members. This is the first report on the prevalence and specificity of Bacillus interactions in a natural setting and provides evidence for the influence of bacterial antagonist interactions in the assemblage of a taxonomically related guild in local communities.
Nutrient requirements for growth of the extreme oligotroph ‘Candidatus Pelagibacter ubique’ HTCC1062 on a defined medium
Authors: Carini Paul , Steindler Laura , Beszteri Sara , Giovannoni Stephen J 
Published: October 2012

Abstract
Chemoheterotrophic marine bacteria of the SAR11 clade are Earth’s most abundant organisms. Following the first cultivation of a SAR11 bacterium, ‘Candidatus Pelagibacter ubique’ strain HTCC1062 (Ca. P. ubique) in 2002, unusual nutritional requirements were identified for reduced sulfur compounds and glycine or serine. These requirements were linked to genome streamlining resulting from selection for efficient resource utilization in nutrient-limited ocean habitats. Here we report the first successful cultivation of Ca. P. ubique on a defined artificial seawater medium (AMS1), and an additional requirement for pyruvate or pyruvate precursors. Optimal growth was observed with the collective addition of inorganic macro- and micronutrients, vitamins, methionine, glycine and pyruvate. Methionine served as the sole sulfur source but methionine and glycine were not sufficient to support growth. Optimal cell yields were obtained when the stoichiometry between glycine and pyruvate was 1:4, and incomplete cell division was observed in cultures starved for pyruvate. Glucose and oxaloacetate could fully replace pyruvate, but not acetate, taurine or a variety of tricarboxylic acid cycle intermediates. Moreover, both glycine betaine and serine could substitute for glycine. Interestingly, glycolate partially restored growth in the absence of glycine. We propose that this is the result of the use of glycolate, a product of phytoplankton metabolism, as both a carbon source for respiration and as a precursor to glycine. These findings are important because they provide support for the hypothesis that some micro-organisms are challenging to cultivate because of unusual nutrient requirements caused by streamlining selection and gene loss. Our findings also illustrate unusual metabolic rearrangements that adapt these cells to extreme oligotrophy, and underscore the challenge of reconstructing metabolism from genome sequences in organisms that have non-canonical metabolic pathways.
Metabolically active microbial communities in marine sediment under high-CO2 and low-pH extremes
Authors: Yanagawa Katsunori , Morono Yuki , de Beer Dirk , Haeckel Matthias , Sunamura Michinari , Futagami Taiki , Hoshino Tatsuhiko , Terada Takeshi , Nakamura Ko-ichi , Urabe Tetsuro , Rehder Gregor , Boetius Antje , Inagaki Fumio 
Published: October 2012

Abstract
Sediment-hosting hydrothermal systems in the Okinawa Trough maintain a large amount of liquid, supercritical and hydrate phases of CO2 in the seabed. The emission of CO2 may critically impact the geochemical, geophysical and ecological characteristics of the deep-sea sedimentary environment. So far it remains unclear whether microbial communities that have been detected in such high-CO2 and low-pH habitats are metabolically active, and if so, what the biogeochemical and ecological consequences for the environment are. In this study, RNA-based molecular approaches and radioactive tracer-based respiration rate assays were combined to study the density, diversity and metabolic activity of microbial communities in CO2-seep sediment at the Yonaguni Knoll IV hydrothermal field of the southern Okinawa Trough. In general, the number of microbes decreased sharply with increasing sediment depth and CO2 concentration. Phylogenetic analyses of community structure using reverse-transcribed 16S ribosomal RNA showed that the active microbial community became less diverse with increasing sediment depth and CO2 concentration, indicating that microbial activity and community structure are sensitive to CO2 venting. Analyses of RNA-based pyrosequences and catalyzed reporter deposition-fluorescence in situ hybridization data revealed that members of the SEEP-SRB2 group within the Deltaproteobacteria and anaerobic methanotrophic archaea (ANME-2a and -2c) were confined to the top seafloor, and active archaea were not detected in deeper sediments (13–30 cm in depth) characterized by high CO2. Measurement of the potential sulfate reduction rate at pH conditions of 3–9 with and without methane in the headspace indicated that acidophilic sulfate reduction possibly occurs in the presence of methane, even at very low pH of 3. These results suggest that some members of the anaerobic methanotrophs and sulfate reducers can adapt to the CO2-seep sedimentary environment; however, CO2 and pH in the deep-sea sediment were found to severely impact the activity and structure of the microbial community.
Comparable light stimulation of organic nutrient uptake by SAR11 and Prochlorococcus in the North Atlantic subtropical gyre
Authors: Gómez-Pereira Paola R , Hartmann Manuela , Grob Carolina , Tarran Glen A , Martin Adrian P , Fuchs Bernhard M , Scanlan David J , Zubkov Mikhail V 
Published: October 2012

Abstract
Subtropical oceanic gyres are the most extensive biomes on Earth where SAR11 and Prochlorococcus bacterioplankton numerically dominate the surface waters depleted in inorganic macronutrients as well as in dissolved organic matter. In such nutrient poor conditions bacterioplankton could become photoheterotrophic, that is, potentially enhance uptake of scarce organic molecules using the available solar radiation to energise appropriate transport systems. Here, we assessed the photoheterotrophy of the key microbial taxa in the North Atlantic oligotrophic gyre and adjacent regions using 33P-ATP, 3H-ATP and 35S-methionine tracers. Light-stimulated uptake of these substrates was assessed in two dominant bacterioplankton groups discriminated by flow cytometric sorting of tracer-labelled cells and identified using catalysed reporter deposition fluorescence in situ hybridisation. One group of cells, encompassing 48% of all bacterioplankton, were identified as members of the SAR11 clade, whereas the other group (24% of all bacterioplankton) was Prochlorococcus. When exposed to light, SAR11 cells took 31% more ATP and 32% more methionine, whereas the Prochlorococcus cells took 33% more ATP and 34% more methionine. Other bacterioplankton did not demonstrate light stimulation. Thus, the SAR11 and Prochlorococcus groups, with distinctly different light-harvesting mechanisms, used light equally to enhance, by approximately one-third, the uptake of different types of organic molecules. Our findings indicate the significance of light-driven uptake of essential organic nutrients by the dominant bacterioplankton groups in the surface waters of one of the less productive, vast regions of the world’s oceans—the oligotrophic North Atlantic subtropical gyre.