Volatile Compounds and Lactic Acid Bacteria in Spontaneous Fermented Sourdough

International Nuclear Information System (INIS)

Kam, W.Y.; Aida, W.M.W.; Sahilah, A.M.; Maskat, M.Y.

2011-01-01

The aim of this study is to identify the predominating lactic acid bacteria (LAB) in a spontaneous fermented wheat sourdough. At the same time, an investigation towards volatile compounds that were produced was also carried out. Lactobacillus plantarum has been identified as the dominant species of lactobacilli with characters of a facultative heterofermentative strain. The generated volatile compounds that were produced during spontaneous fermentation were isolated by solvent extraction method, analysed by gas chromatography (GC), and identified by mass spectrophotometer (MS). Butyric acid has been found to be the main volatile compound with relative abundance of 6.75 % and acetic acid at relative abundance of 3.60 %. Esters that were formed at relatively low amount were butyl formate (1.23 %) and cis 3 hexenyl propionate (0.05 %). Butanol was also found at low amount with relative abundance of 0.60 %. The carbohydrate metabolism of Lactobacillus plantarum may contributed to the production of acetic acid in this study via further catabolism activity on lactic acid that was produced. However, butyric acid was not the major product via fermentation by LAB but mostly carried out by the genus Clostridium via carbohydrate metabolism which needs further investigation. (author)

Volatile isoprenoids as defense compounds during abiotic stress in tropical plants

Science.gov (United States)

Jardine, K.

2015-12-01

Emissions of volatile isoprenoids from tropical forests play central roles in atmospheric processes by fueling atmospheric chemistry resulting in modified aerosol and cloud lifecycles and their associated feedbacks with the terrestrial biosphere. However, the identities of tropical isoprenoids, their biological and environmental controls, and functions within plants and ecosystems remain highly uncertain. As part of the DOE ARM program's GoAmazon 2014/15 campaign, extensive field and laboratory observations of volatile isoprenoids are being conducted in the central Amazon. Here we report the results of our completed and ongoing activities at the ZF2 forest reserve in the central Amazon. Among the results of the research are the suprisingly high abundance of light-dependent volatile isoprenoid emissions across abundant tree genera in the Amazon in both primary and secondary forests, the discovery of highly reactive monoterpene emissions from Amazon trees, and evidence for the importance of volatile isoprenoids in protecting photosynthesis during oxidative stress under elevated temperatures including energy consumption and direct antioxidant functions and a tight connection betwen volatile isoprenoid emissions, photorespiration, and CO2 recycling within leaves. The results highlight the need to model allocation of carbon to isoprenoids during elevated temperature stress in the tropics.

Volatile components and continental material of planets

International Nuclear Information System (INIS)

Florenskiy, K.P.; Nikolayeva, O.V.

1984-01-01

It is shown that the continental material of the terrestrial planets varies in composition from planet to planet according to the abundances and composition of true volatiles (H 2 0, CO 2 , etc.) in the outer shells of the planets. The formation of these shells occurs very early in a planet's evolution when the role of endogenous processes is indistinct and continental materials are subject to melting and vaporizing in the absence of an atmosphere. As a result, the chemical properties of continental materials are related not only to fractionation processes but also to meltability and volatility. For planets retaining a certain quantity of true volatile components, the chemical transformation of continental material is characterized by a close interaction between impact melting vaporization and endogeneous geological processes

Queen volatiles as a modulator of Tetragonisca angustula drone behavior.

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Fierro, Macario M; Cruz-López, Leopoldo; Sánchez, Daniel; Villanueva-Gutiérrez, Rogel; Vandame, Remy

2011-11-01

Tetragonisca angustula mating occurs during the virgin queen nuptial flight, usually in the presence of a drone congregation area (DCA). The presence of virgin queen pheromone is considered the trigger for DCA establishment, although this has not been demonstrated experimentally. We established meliponaries, in different habitats, with T. angustula virgin queens during the main drone reproduction period. Eight DCAs were observed in urban areas, and all established outside or near colonies containing at least one virgin queen. The accumulation of drones in the DCAs occurred from 08:00 to 18:00 h and over 3-35 days. The number of drones in DCAs ranged from 60 to 2,000. In field trials, drones were attracted to virgin queens and also, unexpectedly, to physogastric queens. Volatiles collected from both virgin and physogastric queens elicited strong electoantennogram (EAG) responses from drones. Virgin and physogastric queen volatiles were qualitatively similar, but quantitatively different, in chemical composition. The queen's abdomen was the principal source of these compounds. Isopropyl hexanoate (IPH), the most abundant compound in virgin queen volatiles and one of the most abundant in physogastric queen volatiles, was identified as one of the compounds that elicited EAG responses and was demonstrated to attract drones in a field test.

Volatile elements in Allende inclusions. [Mn, Na and Cl relation to meteorite evolution

Science.gov (United States)

Grossman, L.; Ganapathy, R.

1975-01-01

New data are presented on the relatively volatile elements (Mn, Na, and Cl) in coarse- and fine-grained Ca/Al-rich inclusions of different textures and mineralogy in the Allende meteorite. It is shown that the coarse-grained inclusions condensed from the solar nebula at high temperature and contained vanishingly small quantities of volatile elements at that time. Later, volatiles were added to these during the metamorphism of the Allende parent body. The fine-grained inclusions were also affected by the addition of volatiles during this metamorphism but, unlike the coarse-grained ones, they incorporated large amounts of volatiles when they condensed from the solar nebula, accounting for their higher volatile element contents.

Rare earth element abundances in presolar SiC

Science.gov (United States)

Ireland, T. R.; Ávila, J. N.; Lugaro, M.; Cristallo, S.; Holden, P.; Lanc, P.; Nittler, L.; Alexander, C. M. O'D.; Gyngard, F.; Amari, S.

2018-01-01

Individual isotope abundances of Ba, lanthanides of the rare earth element (REE) group, and Hf have been determined in bulk samples of fine-grained silicon carbide (SiC) from the Murchison CM2 chondrite. The analytical protocol involved secondary ion mass spectrometry with combined high mass resolution and energy filtering to exclude REE oxide isobars and Si-C-O clusters from the peaks of interest. Relative sensitivity factors were determined through analysis of NIST SRM reference glasses (610 and 612) as well as a trace-element enriched SiC ceramic. When normalised to chondrite abundances, the presolar SiC REE pattern shows significant deficits at Eu and Yb, which are the most volatile of the REE. The pattern is very similar to that observed for Group III refractory inclusions. The SiC abundances were also normalised to s-process model predictions for the envelope compositions of low-mass (1.5-3 M⊙) AGB stars with close-to-solar metallicities (Z = 0.014 and 0.02). The overall trace element abundances (excluding Eu and Yb) appear consistent with the predicted s-process patterns. The depletions of Eu and Yb suggest that these elements remained in the gas phase during the condensation of SiC. The lack of depletion in some other moderately refractory elements (like Ba), and the presence of volatile elements (e.g. Xe) indicates that these elements were incorporated into SiC by other mechanisms, most likely ion implantation.

Headspace Analysis of Volatile Compounds Coupled to Chemometrics in Leaves from the Magnoliaceae Family

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Mohamed A. Farag

2015-01-01

Full Text Available Headspace volatile analysis has been used for volatiles profiling in leaves of 4 Magnolia species with a total of 75 compounds were identified. Monterpene hydrocarbons dominated the volatile blend of M. calophylla (86%, M. acuminata (78%, M. virginiana (70% and M. grandiflora (47% with b -pinene and b -ocimene occurring in the largest amounts, whereas sesquiterpenes were the most abundant compounds in M. grandiflora (39%. High levels of oxygenated compounds were only found in M. virginiana volatile blend (11.4% with 2-phenylethyl alcohol as major component. Hierarchical cluster analysis performed on volatiles content revealed the close relationship between M. acuminata and M. calophylla.

[Influence of liquid or solid culture conditions on the volatile components of mycelia of Isariacateinannulata].

Science.gov (United States)

Zhang, Delong; Wang, Xiaodong; Lu, Ruili; Li, Kangle; Hu, Fenglin

2011-12-01

To determine the volatile components of mycelia of Isaria cateinannulata cultured under different culture conditions, and to analyze the relationships between the culture conditions and volatile metabolites. Mycelia were cultured in solid plates with SDAY medium and liquid shake flasks with SDY medium. The culture conditions were at 25 degrees C and 8 days. Volatile components in the mycelia of I. cateinannulata were extracted with simultaneous distillation extraction and analyzed by gas chromatography-mass spectrometry. Alkenes, alkanes, heterocyclic and polycyclic aromatic hydrocarbons (PAH) were existed abundantly both in the mycelia of liquid and solid cultures, but the kinds and relative concentrations of the volatile components in mycelia of liquid and solid cultures were very different. Forty-one compounds were identified from the mycelia of solid culture and 32 compounds were identified from the mycelia of liquid culture. Esters, quinones and oximes were only found in solid cultured mycelia whereas carboxylic acids were only discovered in the mycelia of liquid culture. At the same time, mycelia of liquid culture contained much more phenols. The most abundant compounds in mycelia of liquid and solid cultures were hydrocarbons. The volatile extracts of solid cultured mycelia contained 57.6% alkenes and 9.19% alkanes. The volatile extracts of liquid cultured mycelia contained 7.85% alkenes and 22.4% alkanes. Liquid or solid culture conditions influenced the volatile components of mycelia of I. cateinannulata.

Volatile Constituents of Different Plant Parts and Populations of Malabaila aurea Boiss. from Montenegro

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Ivan Vučković

2014-03-01

Full Text Available The volatile constituents of different plant parts and populations of Malabaila aurea Boiss. from Montenegro were obtained by simultaneous distillation-extraction and analyzed by GC-FID and GC-MS. A total of 12 samples were examined and 45 compounds were identified. The volatile content of different M. aurea populations was very similar, while the volatile fractions obtained from different plant parts showed significant qualitative and quantitative differences. The most abundant compounds found in stems & leaves were apiole (51.0-56.3%, myristicin (16.3-25.4%, and falcarinol (4.1-10.7%. The roots showed the same major components, but with different relative abundances: 30.9-49.1% of apiole, 12.9-34.7% of falcarinol, and 9.9-31.1% of myristicin. The volatile constituents of fruits & flowers were remarkably different, containing up to 71.2-80.5% octyl butyrate, 11.4-18.0% octanol, and 2.7-6.8% octyl hexanoate. The results were discussed as possible indication of relatedness of Malabaila aurea and Pastinacasativa (parsnip .

Microbial cycling of isoprene, the most abundantly produced biological volatile organic compound on Earth.

Science.gov (United States)

McGenity, Terry J; Crombie, Andrew T; Murrell, J Colin

2018-04-01

Isoprene (2-methyl-1,3-butadiene), the most abundantly produced biogenic volatile organic compound (BVOC) on Earth, is highly reactive and can have diverse and often detrimental atmospheric effects, which impact on climate and health. Most isoprene is produced by terrestrial plants, but (micro)algal production is important in aquatic environments, and the relative bacterial contribution remains unknown. Soils are a sink for isoprene, and bacteria that can use isoprene as a carbon and energy source have been cultivated and also identified using cultivation-independent methods from soils, leaves and coastal/marine environments. Bacteria belonging to the Actinobacteria are most frequently isolated and identified, and Proteobacteria have also been shown to degrade isoprene. In the freshwater-sediment isolate, Rhodococcus strain AD45, initial oxidation of isoprene to 1,2-epoxy-isoprene is catalyzed by a multicomponent isoprene monooxygenase encoded by the genes isoABCDEF. The resultant epoxide is converted to a glutathione conjugate by a glutathione S-transferase encoded by isoI, and further degraded by enzymes encoded by isoGHJ. Genome sequence analysis of actinobacterial isolates belonging to the genera Rhodococcus, Mycobacterium and Gordonia has revealed that isoABCDEF and isoGHIJ are linked in an operon, either on a plasmid or the chromosome. In Rhodococcus strain AD45 both isoprene and epoxy-isoprene induce a high level of transcription of 22 contiguous genes, including isoABCDEF and isoGHIJ. Sequence analysis of the isoA gene, encoding the large subunit of the oxygenase component of isoprene monooxygenase, from isolates has facilitated the development of PCR primers that are proving valuable in investigating the ecology of uncultivated isoprene-degrading bacteria.

A volatile topic: Parsing out the details of Earth's formation through experimental metal-silicate partitioning of volatile and moderately volatile elements

Science.gov (United States)

Mahan, B. M.; Siebert, J.; Blanchard, I.; Badro, J.; Sossi, P.; Moynier, F.

2017-12-01

Volatile and moderately volatile elements display different volatilities and siderophilities, as well as varying sensitivity to thermodynamic controls (X, P, T, fO2) during metal-silicate differentiation. The experimental determination of the metal-silicate partitioning of these elements permits us to evaluate processes controlling the distribution of these elements in Earth. In this work, we have combined metal-silicate partitioning data and results for S, Sn, Zn and Cu, and input these characterizations into Earth formation models. Model parameters such as source material, timing of volatile delivery, fO2 path, and degree of impactor equilibration were varied to encompass an array of possible formation scenarios. These models were then assessed to discern plausible sets of conditions that can produce current observed element-to-element ratios (e.g. S/Zn) in the Earth's present-day mantle, while also satisfying current estimates on the S content of the core, at no more than 2 wt%. The results of our models indicate two modes of accretion that can maintain chondritic element-to-element ratios for the bulk Earth and can arrive at present-day mantle abundances of these elements. The first mode requires the late addition of Earth's entire inventory of these elements (assuming a CI-chondritic composition) and late-stage accretion that is marked by partial equilibration of large impactors. The second, possibly more intuitive mode, requires that Earth accreted - at least initially - from volatile poor material preferentially depleted in S relative to Sn, Zn, and Cu. From a chemical standpoint, this source material is most similar to type I chondrule rich (and S poor) materials (Hewins and Herzberg, 1996; Mahan et al., 2017; Amsellem et al., 2017), such as the metal-bearing carbonaceous chondrites.

Effect of different cooking methods on lipid oxidation and formation of volatile compounds in foal meat.

Science.gov (United States)

Domínguez, Rubén; Gómez, María; Fonseca, Sonia; Lorenzo, José M

2014-06-01

The influence of four different cooking methods (roasting, grilling, microwaving and frying) on cooking loss, lipid oxidation and volatile profile of foal meat was studied. Cooking loss were significantly (Pcooking methods increased TBARs content, since high temperature during cooking causes increased oxidation in foal steaks, this increase was significantly (Pcooking methods led to increased total volatile compounds (between 366.7 and 633.1AU×10(6)/g dry matter) compared to raw steaks (216.4AU×10(6)/g dry matter). The roasted steaks showed the highest volatile content, indicating that increased cooking temperature increases the formation of volatile compounds. Aldehydes were the most abundant compounds in cooked samples, with amounts of 217.2, 364.5, 283.5 and 409.1AU×10(6)/g dry matter in grilled, microwaved, fried and roasted samples, respectively, whereas esters were the most abundant compounds in raw samples, with mean amounts of 98.8AU×10(6)/g dry matter. Copyright © 2014 Elsevier Ltd. All rights reserved.

Bacterial contribution to iodine volatilization in the environment

Energy Technology Data Exchange (ETDEWEB)

Amachi, S; Kasahara, M; Fujii, T [Chiba Univ., Dept. of Bioresources Chemistry, Matsudo, Chiba (Japan); Muramatsu, Y [National Inst. of Radiological Sciences, Chiba (Japan)

2003-09-01

The roles of microorganisms in iodine volatilization from the environment were studied. More than 100 bacterial strains were isolated from various environments such as soils, seawater and marine sediments, and were examined their capacities for volatilizing iodine. Approximately 40% of these bacteria showed significant capacities for volatilizing iodine. Gas chromatographic determinations revealed that the chemical species of gaseous iodine is methyl iodide (CH{sub 3}I). Phylogenetic analysis based on 16S ribosomal DNA showed that these 'iodine-volatilizing bacteria' are widely distributed through the bacterial domain. The iodide-methylating reaction was mediated by an enzyme protein with S-adenosyl-L-methionine (SAM) as the methyl donor. We then estimated bacterial contribution to iodine volatilization from soils. Iodine in soils was volatilized mainly as CH{sub 3}I. CH{sub 3}I emission was enhanced in the presence of glucose or yeast extract, but was inhibited by autoclaving of soils. Little CH{sub 3}I was produced under anaerobic conditions. Furthermore, the addition of streptomycin and tetracycline, antibiotics which inhibit bacterial growth, strongly inhibited CH{sub 3}I emission, while a fungal inhibitor cycloheximide caused little effect. These results suggest that iodine in soils is volatilized as CH{sub 3}I mainly by the action of aerobic soil bacteria. Similar experiment was carried out by using sea water samples. The emission of iodine from sea waters occurred biologically, and bacterial (and also other microbial) contribution was confirmed. Our results suggest that iodine is methylated and volatilized into the atmosphere as a result of bacterial activities. Since bacteria are so abundant and widespread in the environments, they may significantly contribute to global iodine volatilization. This indicates that if {sup 129}I would be released from nuclear facilities, weapons testing or ground storage of nuclear wastes, the pathway of volatilization by

Volatile constituents of essential oils of Eleocharis pauciflora (Light ...

African Journals Online (AJOL)

The investigation of the volatile compounds of essential oils of Eleocharis pauciflora (Light) Link and Eleocharis uniglumis (Link) J.A. Shultes by gas chromatography/mass spectrometry (GC/MS) led to the identification of 20 and 23 compounds, respectively. The presented essential oils were characterized by the abundance ...

Volatile element loss during planetary magma ocean phases

Science.gov (United States)

Dhaliwal, Jasmeet K.; Day, James M. D.; Moynier, Frédéric

2018-01-01

Moderately volatile elements (MVE) are key tracers of volatile depletion in planetary bodies. Zinc is an especially useful MVE because of its generally elevated abundances in planetary basalts, relative to other MVE, and limited evidence for mass-dependent isotopic fractionation under high-temperature igneous processes. Compared with terrestrial basalts, which have δ66Zn values (per mille deviation of the 66Zn/64Zn ratio from the JMC-Lyon standard) similar to some chondrite meteorites (∼+0.3‰), lunar mare basalts yield a mean δ66Zn value of +1.4 ± 0.5‰ (2 st. dev.). Furthermore, mare basalts have average Zn concentrations ∼50 times lower than in typical terrestrial basaltic rocks. Late-stage lunar magmatic products, including ferroan anorthosite, Mg- and Alkali-suite rocks have even higher δ66Zn values (+3 to +6‰). Differences in Zn abundance and isotopic compositions between lunar and terrestrial rocks have previously been interpreted to reflect evaporative loss of Zn, either during the Earth-Moon forming Giant Impact, or in a lunar magma ocean (LMO) phase. To explore the mechanisms and processes under which volatile element loss may have occurred during a LMO phase, we developed models of Zn isotopic fractionation that are generally applicable to planetary magma oceans. Our objective was to identify conditions that would yield a δ66Zn signature of ∼+1.4‰ within the lunar mantle. For the sake of simplicity, we neglect possible Zn isotopic fractionation during the Giant Impact, and assumed a starting composition equal to the composition of the present-day terrestrial mantle, assuming both the Earth and Moon had zinc 'consanguinity' following their formation. We developed two models: the first simulates evaporative fractionation of Zn only prior to LMO mixing and crystallization; the second simulates continued evaporative fractionation of Zn that persists until ∼75% LMO crystallization. The first model yields a relatively homogenous bulk solid

Stochastic volatility of volatility in continuous time

DEFF Research Database (Denmark)

Barndorff-Nielsen, Ole; Veraart, Almut

This paper introduces the concept of stochastic volatility of volatility in continuous time and, hence, extends standard stochastic volatility (SV) models to allow for an additional source of randomness associated with greater variability in the data. We discuss how stochastic volatility...... of volatility can be defined both non-parametrically, where we link it to the quadratic variation of the stochastic variance process, and parametrically, where we propose two new SV models which allow for stochastic volatility of volatility. In addition, we show that volatility of volatility can be estimated...

Volatile inventories in clathrate hydrates formed in the primordial nebula.

Science.gov (United States)

Mousis, Olivier; Lunine, Jonathan I; Picaud, Sylvain; Cordier, Daniel

2010-01-01

The examination of ambient thermodynamic conditions suggests that clathrate hydrates could exist in the Martian permafrost, on the surface and in the interior of Titan, as well as in other icy satellites. Clathrate hydrates are probably formed in a significant fraction of planetesimals in the solar system. Thus, these crystalline solids may have been accreted in comets, in the forming giant planets and in their surrounding satellite systems. In this work, we use a statistical thermodynamic model to investigate the composition of clathrate hydrates that may have formed in the primordial nebula. In our approach, we consider the formation sequence of the different ices occurring during the cooling of the nebula, a reasonable idealization of the process by which volatiles are trapped in planetesimals. We then determine the fractional occupancies of guests in each clathrate hydrate formed at a given temperature. The major ingredient of our model is the description of the guest-clathrate hydrate interaction by a spherically averaged Kihara potential with a nominal set of parameters, most of which are fitted to experimental equilibrium data. Our model allows us to find that Kr, Ar and N2 can be efficiently encaged in clathrate hydrates formed at temperatures higher than approximately 48.5 K in the primitive nebula, instead of forming pure condensates below 30 K. However, we find at the same time that the determination of the relative abundances of guest species incorporated in these clathrate hydrates strongly depends on the choice of the parameters of the Kihara potential and also on the adopted size of cages. Indeed, by testing different potential parameters, we have noted that even minor dispersions between the different existing sets can lead to non-negligible variations in the determination of the volatiles trapped in clathrate hydrates formed in the primordial nebula. However, these variations are not found to be strong enough to reverse the relative abundances

THE VOLATILE COMPOSITION AND ACTIVITY OF COMET 103P/HARTLEY 2 DURING THE EPOXI CLOSEST APPROACH

International Nuclear Information System (INIS)

Dello Russo, N.; Vervack, R. J. Jr; Lisse, C. M.; Weaver, H. A.; Kawakita, H.; Kobayashi, H.; Cochran, A. L.; Harris, W. M.; McKay, A. J.; Biver, N.; Bockelee-Morvan, D.; Crovisier, J.

2011-01-01

We report time-resolved measurements of the absolute and relative abundances of eight parent volatiles (H 2 O, CH 3 OH, C 2 H 6 , C 2 H 2 , NH 3 , HCN, H 2 CO, and HC 3 N) in the coma of 103P/Hartley 2 on UT 2010 November 4, the date the EPOXI spacecraft made its closest approach to the comet, using high-dispersion infrared spectroscopy with NIRSPEC at the W. M. Keck Observatory. Overall gas and dust production increased by roughly 60% between UT 10:49 and 15:54. Differences in the spatial distributions of species in the coma suggest icy sources of different composition in the nucleus of 103P/Hartley 2. However, differences in the relative abundances of species with time are minor, suggesting either internal compositional heterogeneity in 103P/Hartley 2 is small compared with the diversity of chemistry observed within the comet population, or more significant heterogeneity exists on scales smaller than our spatial resolution. Observations contemporaneous with the EPOXI encounter test how compositional heterogeneity over the surface and the inner coma of a comet manifests itself in remote-sensing observations of the bulk coma.

Organic and volatile elements in the solar system

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Remusat L.

2012-01-01

Full Text Available Chondrites and comets have accreted primitive materials from the early solar system. Those materials include organics, water and other volatile components. The most primitive chondrites and comets have undergone few modifications on their respective parent bodies and can deliver to laboratories components that were present at the origin of the protosolar nebula. Here I present a review of the organic material and volatile components that have been studied in the most primitive chondrites, and the last data from the stardust mission about the cometary record. This paper focuses on materials that can be studied in laboratories, by mass spectrometry, ion probes or organic chemistry techniques.

Using Spectroscopy to Infer the Eruption Style and Volatile History of Volcanic Tephras

Science.gov (United States)

McBride, M. J.; Horgan, B. H. N.; Rowe, M. C.; Wall, K. T.; Oxley, B. M.

2017-12-01

The interaction between volatiles and magma strongly influences volcanic eruption styles, and results in an increase in the glass component of volcanic tephra. On Earth, both phreatomagmatic and magmatic explosive eruptions create glassy tephras. Phreatomagmatic eruptions form abundant glass by quickly quenching lava through interaction with meteoric water while magmatic eruptions create less glass through slower cooling within larger pyroclasts or eruption columns. Wall et al. (2014) used X-ray diffraction (XRD) of diverse tephra samples to show that glass content correlates with eruption style, as magmatic samples contain less glass than phreatomagmatic samples. While use of XRD is limited to Earth and the Curiosity rover on Mars, orbital spectroscopy is much a more common technique in the exploration of terrestrial bodies. In this study, we evaluate whether or not spectroscopy can be used to infer eruption style and thus volatile history. Visible/near-infrared (VNIR) and thermal-infrared (TIR) spectra were collected of the Wall et al. (2014) tephra samples, and were analyzed for trends related to glass content and thus eruption style. VNIR spectra can detect glass at high abundances as well as hydrothermal alteration minerals produced during interactions with meteoric water. Using TIR, glass abundances can be derived by deconvolving the spectra with a standard spectral library; however, due to the non-unique spectral shape of glass, intermediate to high glass abundances in tephras are difficult to differentiate using TIR alone. Synthetic mixtures of glass and crystalline minerals verify these results. Therefore, the most effective method for determining glass abundance and thus eruption style from volcanic deposits is a combination of VNIR and TIR spectral analysis. Using standard planetary remote sensing instrumentation to infer eruption styles will provide a new window into the volcanic and volatile histories of terrestrial bodies.

Volatile aromatic compounds in Mexico City atmosphere: levels and source apportionment

Energy Technology Data Exchange (ETDEWEB)

Mugica, V. [Universidad Autonoma Metropolitana - Unidad Azcapotzalco, Mexico, D.F. (Mexico); Ruiz, M.E. [Instituto Mexicano del Petroleo, Mexico, D.F. (Mexico); Watson, J.; Chow, J. [Desert Research Institute, Reno, Nevada (United States)

2003-01-01

Samples of ambient air were simultaneously collected at three different sites of Mexico City in March of 1997 in order to quantify the most abundant volatile aromatic compounds and estimate the source contributions by application of the chemical mass balance model (CMB). Volatile aromatic compounds were around 20% of the total of non-methane hydrocarbons present in morning air samples. The most abundant volatile aromatic species in urban air were toluene and xylenes followed by 1, 2, 4 trimethylbenzene, benzene, ethylbenzene, metaethyltoluene, 1, 3, 5 trimethylbenzene, styrene, n propylbenzene, and isopropylbenzene. Sampling campaigns were carried out at crossroads, a bus station, a parking place, and areas where solvents and petroleum distillates are used, with the objective of determining people's exposure to volatile aromatic compounds. The CMB was applied for estimating the contribution of different sources to the presence of each one of the most abundant aromatic compounds. Motor vehicle exhaust was the main source of all aromatic compounds, especially gasoline exhaust, although diesel exhausts and asphalt operations also accounted for toluene, xylenes, ethylbenzene, propylbenzenes, and styrene. Graphic arts and paint applications had an important impact on the presence of toluene. [Spanish] Se colectaron simultaneamente muestras de aire ambiente en tres sitios de la Ciudad de Mexico durante el mes de marzo de 1997 con el fin de conocer las concentraciones y el origen de compuestos aromaticos utilizando el modelo de balance de masa de especies quimicas (CMB). Los compuestos aromaticos volatiles representaron alrededor del 20% del total de hidrocarburos no metalicos presentes en las muestras matutinas colectadas. Las especies aromaticas volatiles mas abundantes en el ambiente fueron el tolueno y los xilenos, seguidos por 1, 2, 4 trimetilbenceno, benceno, etilbenceno, metaetiltolueno, nporpilbenceno, isopropilbenceno, 1, 3, 5 trimetilbenceno y estireno. Se

A-type Stellar Abundances: A Corollary to Herschel Observations of Debris Disks

Science.gov (United States)

Draper, Zachary H.; Matthews, Brenda; Venn, Kim; Lambert, David; Kennedy, Grant; Sitnova, Tatyana

2018-04-01

In order to assess the relationship between metallicity and exoplanetary systems, we compare the abundances of AF-type main-sequence stars with debris disk properties assessed using Herschel observations of an unbiased survey of nearby stars. Hot stars are not as commonly observed, given their unique constraints in data reduction, lack of metal lines, and “astrophysical noise” from rotation speed. Here, we address that deficiency using new and archival spectra of 83 AF-type stars. We measure the abundances of a few species in addition to Fe in order to classify the stars with Ap/Am or Lambda Boo signatures. Lambda Boo stars have a chemical signature of solar-abundant volatile species and sub-solar refractory abundances that is hypothesized to be altered by the pollution of volatiles. Overall, we see no correlation between debris disks and metallicity, primarily because the sample size is cut significantly when using only reliable fits to the spectroscopic data. The abundance measured from the Mg II 4481 blend is a useful diagnostic because it can be reliably measured at large v·sin(i) and is found to be lower around stars with bright debris disks. We find that Lambda Boo stars have brighter debris disks compared to a bias-free sample of AF stars. The trend with disk brightness and Mg abundances suggests pollution effects can be significant and used as a marker for the stability of planetary systems. We explore trends with other species, such as with the C/O ratios, but are significantly limited by the low number of reliable detections.

Space-weathering processes and products on volatile-rich asteroids

Science.gov (United States)

Britt, D.; Schelling, P.; Consolmagno, G.; Bradley, T.

2014-07-01

implications for our planetary science and, potentially, the formation of the precursors of life. First, the range of weathering products seen in remotely-sensed data, meteorites, and returned samples are not random, but the predictable outcome of the source region's mineral kinetics and chemical feedstock. Weathering products do not have to be optically active like the npFe0 that produces the lunar red slope; on the contrary, probably most weathering products are spectrally neutral or even suppress an object's near-IR reflectance spectrum. In the case of volatile-rich parent bodies, a major weathering product is a range of carbon-rich compounds. But an additional result of considerable interest is the generation of pre-biotic compounds as a routine and predictable byproduct of common space-weathering processes. Any atmosphereless body around any star with mafic silicate mineral compositions and volatile feedstocks should create amino acids as a standard byproduct of space weathering. The precursors of life are probably abundant in any space-weathered asteroid belt, in any solar system, and only wait being accreted to a hospitable environment.

Multidimensional analysis of cannabis volatile constituents: identification of 5,5-dimethyl-1-vinylbicyclo[2.1.1]hexane as a volatile marker of hashish, the resin of Cannabis sativa L.

Science.gov (United States)

Marchini, Marie; Charvoz, Céline; Dujourdy, Laurence; Baldovini, Nicolas; Filippi, Jean-Jacques

2014-11-28

The volatile constituents of drug samples derived from Cannabis sativa L. were investigated by means of headspace solid phase microextraction (HS-SPME) and gas chromatography techniques (GC-MS, GC×GC-MS). Samples of cannabis herb and hashish showed clear differences in their volatile chemical profiles, mostly resulting from photo-oxidation processes occurring during the transformation of fresh cannabis herb into hashish. Most unexpectedly, we could demonstrate hashish samples as containing remarkable amounts of a rare and unusual monoterpene - 5,5-dimethyl-1-vinylbicyclo[2.1.1]hexane - among the volatile compounds detected in their headspaces. We gave evidence for the formation of this compound from the light induced rearrangement of β-myrcene during the manufacture of hashish. In view of its high abundance among volatile constituents of cannabis resin and its scarce occurrence in other natural volatile extracts, we propose to rename this specific monoterpene hashishene. Copyright © 2014 Elsevier B.V. All rights reserved.

Distribution of Alkalis (Na, Cs, Rb) Between Silicate and Sulfide: Implications for Planetary Volatile Depletion

Science.gov (United States)

Boujibar, A.; Fei, Y.; Righter, K.; Du, Z.; Bullock, E.

2018-01-01

The abundances of volatile elements in the Earth's mantle are correlated with their temperatures of condensation. This depletion can be due to either incomplete condensation of the elements during the nebula condensation or evaporation processes during planetary growth. Elements that have affinities with metals (siderophile) and sulfides (chalcophile) are additionally depleted due to their segregation into the core. Therefore, study of lithophile elements could be useful to isolate processes of volatilization and their effect on the abundance of the elements in the Earth's mantle. However, the correlation of these lithophile elements including alkali elements, with their temperatures of condensation shows a significant scatter, which is difficult to reconcile with a depletion by vaporization or incomplete condensation alone.

Chemical Diversity in Volatiles of Helichrysum plicatum DC. Subspecies in Turkey

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Bintuğ Öztürk

2014-07-01

Full Text Available In the present work three subspecies of Helichrysum plicatum DC. (Helichrysum plicatum DC. subsp. plicatum, Helichrysum plicatum DC. subsp. polyphillum (Ledeb P.H.Davis & Kupicha and Helichrysum plicatum DC. subsp. isauricum Parolly were investigated for the essential oil chemical compositions. The volatiles were obtained by conventional hydrodistillation of aerial parts and microdistillation of inflorescences. Subsequent gas chromatography (GC-FID and gas chromatography coupled to mass spectrometry (GC/MS revealed chemical diversity in compositions of the volatiles analyzed. A total of 199 compounds were identified representing 73.9-98.3% of the volatiles compositions. High abundance of fatty acids and their esters (24.9-70.8% was detected in the herb volatiles of H. plicatum subsp. polyphyllum and H. plicatum subsp. isauricum. The inflorescences of Helichrysum subspecies were found to be rich in monoterpenes (15.0-93.1%, fatty acids (0.1-36.3% and sesquiterpenes (1.1-25.5%. The inflorescence volatiles of H. plicatum subsp. isauricum were distinguished by predomination of monoterpene hydrocarbons (93.1% with fenchene (88.3% as the major constituent

Different methods for volatile sampling in mammals.

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Marlen Kücklich

Full Text Available Previous studies showed that olfactory cues are important for mammalian communication. However, many specific compounds that convey information between conspecifics are still unknown. To understand mechanisms and functions of olfactory cues, olfactory signals such as volatile compounds emitted from individuals need to be assessed. Sampling of animals with and without scent glands was typically conducted using cotton swabs rubbed over the skin or fur and analysed by gas chromatography-mass spectrometry (GC-MS. However, this method has various drawbacks, including a high level of contaminations. Thus, we adapted two methods of volatile sampling from other research fields and compared them to sampling with cotton swabs. To do so we assessed the body odor of common marmosets (Callithrix jacchus using cotton swabs, thermal desorption (TD tubes and, alternatively, a mobile GC-MS device containing a thermal desorption trap. Overall, TD tubes comprised most compounds (N = 113, with half of those compounds being volatile (N = 52. The mobile GC-MS captured the fewest compounds (N = 35, of which all were volatile. Cotton swabs contained an intermediate number of compounds (N = 55, but very few volatiles (N = 10. Almost all compounds found with the mobile GC-MS were also captured with TD tubes (94%. Hence, we recommend TD tubes for state of the art sampling of body odor of mammals or other vertebrates, particularly for field studies, as they can be easily transported, stored and analysed with high performance instruments in the lab. Nevertheless, cotton swabs capture compounds which still may contribute to the body odor, e.g. after bacterial fermentation, while profiles from mobile GC-MS include only the most abundant volatiles of the body odor.

Arsenic volatilization in model anaerobic biogas digesters

International Nuclear Information System (INIS)

Mestrot, Adrien; Xie, Wan-Ying; Xue, Ximei; Zhu, Yong-Guan

2013-01-01

Highlights: • Arsenic is volatilized form all model anaerobic digesters, including the non-treated ones. • Volatile As species can be identified and quantified in all digesters. • Non-arsenic treated digesters volatilization rates are higher than Roxarsone treated ones. - Abstract: Arsenic is a class 1 non-threshold carcinogen which is highly ubiquitous. Arsenic undergoes many different transformations (biotic or abiotic) between and within environmental compartments, leading to a number of different chemical species possessing different properties and toxicities. One specific transformation is As biotic volatilization which is coupled with As biomethylation and has been scarcely studied due to inherent sampling issues. Arsenic methylation/volatilization is also linked with methanogenesis and occurs in anaerobic environments. In China, rice straw and animal manure are very often used to produce biogas and both can contain high amounts of As, especially if the rice is grown in areas with heavy mining or smelting industries and if Roxarsone is fed to the animals. Roxarsone is an As-containing drug which is widely used in China to control coccidian intestinal parasites, to improve feed efficiency and to promote rapid growth. Previous work has shown that this compound degrades to inorganic As under anaerobic conditions. In this study the focus is on biotic transformations of As in small microcosms designed as biogas digester models (BDMs) using recently validated As traps, thus, enabling direct quantification and identification of volatile As species. It is shown that although there was a loss of soluble As in the BDMs, their conditions favored biomethylation. All reactors produced volatile As, especially the monomethylarsonic acid spiked ones with 413 ± 148 ng As (mean ± SD, n = 3) which suggest that the first methylation step, from inorganic As, is a limiting factor. The most abundant species was trimethylarsine, but the toxic arsine was present in the

Distribution, movement, and evolution of the volatile elements in the lunar regolith

International Nuclear Information System (INIS)

Gibson, E.K. Jr.

1975-01-01

The abundances and distributions of carbon, nitrogen, and sulfur in lunar soils are reviewed. Carbon and nitrogen have a predominantly extra-lunar origin in lunar soils and breccias, while sulfur is mostly indigeneous to the Moon. The lunar processes which effect the movement, distribution, and evolution of carbon, nitrogen, and sulfur, along with the volatile alkali elements sodium, potassium, and rubidium during regolith processes are discussed. Possible mechanisms which may result in the addition to or loss from the Moon of these volatile elements are considered. (Auth.)

Distribution, movement, and evolution of the volatile elements in the lunar regolith

Science.gov (United States)

Gibson, E. K., Jr.

1975-01-01

The abundances and distributions of carbon, nitrogen, and sulfur in lunar soils are reviewed. Carbon and nitrogen have a predominantly extra-lunar origin in lunar soils and breccias, while sulfur is mostly indigeneous to the moon. The lunar processes which effect the movement, distribution, and evolution of carbon, nitrogen, and sulfur, along with the volatile alkali elements sodium, potassium, and rubidium during regolith processes are discussed. Possible mechanisms which may result in the addition to or loss from the moon of these volatile elements are considered.

Abundances in the diffuse interstellar medium

International Nuclear Information System (INIS)

Harris, A.W.

1988-04-01

The wealth of interstellar absorption line data obtained with the Copernicus and IUE satellites has opened up a new era in studies of the interstellar gas. It is now well established that certain elements, generally those with high condensation temperatures, are substantially under-abundant in the gas-phase relative to total solar or cosmic abundances. This depletion of elements is due to the existence of solid material in the form of dust grains in the interstellar medium. Surprisingly, however, recent surveys indicate that even volatile elements such as Zn and S are significantly depleted in many sight lines. Developments in this field which have been made possible by the large base of UV interstellar absorption line data built up over recent years are reviewed and the implications of the results for our understanding of the physical processes governing depletion are discussed. (author)

Abundances of Volatile - Bearing Species from Evolved Gas Analysis of Samples from the Rocknest Aeolian Bedform in Gale Crater

Science.gov (United States)

Archer, P. D., Jr.; Franc, H. B.; Sutter, B.; McAdam, A.; Ming, D. W.; Morris, R. V.; Mahaffy, P. R.

2013-01-01

The Sample Analysis at Mars (SAM) instrument suite on board the Mars Science Laboratory (MSL) recently ran four samples from an aeolian bedform named Rocknest. SAM detected the evolution of H2O, CO2, O2, and SO2, indicative of the presence of multiple volatile bearing species (Fig 1). The Rocknest bedform is a windblown deposit selected as representative of both the windblown material in Gale crater as well as the globally-distributed martian dust. Four samples of Rocknest material were analyzed by SAM, all from the fifth scoop taken at this location. The material delivered to SAM passed through a 150 m sieve and is assumed to have been well mixed during the sample acquisition/preparation/handoff process. SAM heated the Rocknest samples to approx.835 C at a ramp rate of 35 C/min with a He carrier gas flow rate of apprx.1.5 standard cubic centimeters per minute and at an oven pressure of 30 mbar [1]. Evolved gases were detected by a quadrupole mass spectrometer (QMS). This abstract presents the molar abundances of H2O, CO2, O2, and SO2 as well as their concentration in rocknest samples using an estimated sample mass.

Analysis of the Volatile Profile of Core Chinese Mango Germplasm by Headspace Solid-Phase Microextraction Coupled with Gas Chromatography-Mass Spectrometry

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Xiao-Wei Ma

2018-06-01

Full Text Available Despite abundant published research on the volatile characterization of mango germplasm, the aroma differentiation of Chinese cultivars remains unclear. Using headspace solid phase microextraction (HS-SPME coupled with gas chromatography–mass spectrometry (GC-MS, the composition and relative content of volatiles in 37 cultivars representing the diversity of Chinese mango germplasm were investigated. Results indicated that there are distinct differences in the components and content of volatile compounds among and within cultivars. In total, 114 volatile compounds, including 23 monoterpenes, 16 sesquiterpenes, 29 non-terpene hydrocarbons, 25 esters, 11 aldehydes, five alcohols and five ketones, were identified. The total volatile content among cultivars ranged from 211 to 26,022 μg/kg fresh weight (FW, with 123-fold variation. Terpene compounds were the basic background volatiles, and 34 cultivars exhibited abundant monoterpenes. On the basis of hierarchical cluster analysis (HCA and principal component analysis (PCA, terpinolene and α-pinene were important components constituting the aroma of Chinese mango cultivars. Most obviously, a number of mango cultivars with high content of various aroma components were observed, and they can serve as potential germplasms for both breeding and direct use.

Differential Contribution of Jasmine Floral Volatiles to the Aroma of Scented Green Tea

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Jian-Xia Shen

2017-01-01

Full Text Available Tea volatiles’ generation and retention over manufacturing processes are crucial for tea quality. In this study, floral volatile adsorption and retention in green tea scented with Jasminum sambac flowers were examined over the scenting process. Out of 34 enhanced volatiles in the scented tea, β-ionone, β-linalool, indole, and methyl anthranilate were the most potent odorants with 5.1–45.2-fold higher odor activity values than the corresponding controls in the nonscented tea. Scenting efficiencies for the floral volatiles retained in the scented tea (the percentage of volatile abundance over its corresponding amount in jasmine flowers ranged from 0.22% for α-farnesene to 75.5% for β-myrcene. Moreover, due to additional rounds of heat treatment for scented green tea manufacturing, some volatiles such as carotenoid-derived geraniol and β-ionone and lipid-derived (Z-jasmone were heat-enhanced and others such as nonanal were heat-desorbed in the scented green tea. Our study revealed that dynamic volatile absorption and desorption collectively determined tea volatile retention and tea aroma. Our findings may have a great potential for practical improvement of tea aroma.

Aroma profile and volatiles odor activity along gold cultivar pineapple flesh.

Science.gov (United States)

Montero-Calderón, Marta; Rojas-Graü, María Alejandra; Martín-Belloso, Olga

2010-01-01

Physicochemical attributes, aroma profile, and odor contribution of pineapple flesh were studied for the top, middle, and bottom cross-sections cut along the central axis of Gold cultivar pineapple. Relationships between volatile and nonvolatile compounds were also studied. Aroma profile constituents were determined by headspace solid-phase microextraction at 30 °C, followed by gas chromatography/mass spectrometry analysis. A total of 20 volatile compounds were identified and quantified. Among them, esters were the major components which accounted for 90% of total extracted aroma. Methyl butanoate, methyl 2-methyl butanoate, and methyl hexanoate were the 3 most abundant components representing 74% of total volatiles in pineapple samples. Most odor active contributors were methyl and ethyl 2-methyl butanoate and 2,5-dimethyl 4-methoxy 3(2H)-furanone (mesifuran). Aroma profile components did not vary along the fruit, but volatile compounds content significantly varied (P fresh-cut pineapple trays, compromising consumer perception and acceptance of the product. Such finding highlighted the need to include volatiles content and SSC/TA ratio and their variability along the fruit as selection criteria for pineapples to be processed and quality assessment of the fresh-cut fruit. © 2010 Institute of Food Technologists®

Volatile elements - water, carbon, nitrogen, noble gases - on Earth

Science.gov (United States)

Marty, B.

2017-12-01

Understanding the origin and evolution of life-bearing volatile elements (water, carbon, nitrogen) on Earth is a fruitful and debated area of research. In his pioneering work, W.W. Rubey inferred that the terrestrial atmosphere and the oceans formed from degassing of the mantle through geological periods of time. Early works on noble gas isotopes were consistent with this view and proposed a catastrophic event of mantle degassing early in Earth's history. We now have evidence, mainly from noble gas isotopes, that several cosmochemical sources contributed water and other volatiles at different stages of Earth's accretion. Potential contributors include the protosolar nebula gas that equilibrated with magma oceans, inner solar system bodies now represented by chondrites, and comets. Stable isotope ratios suggest volatiles where primarily sourced by planetary bodies from the inner solar system. However, recent measurements by the European Space Agency Rosetta probe on the coma of Comet 67P/Churyumov-Gerasimenko permit to set quantitative constraints on the cometary contribution to the surface of our planet. The surface and mantle reservoirs volatile elements exchanged volatile elements through time, with rates that are still uncertain. Some mantle regions remained isolated from whole mantle convection within the first tens to hundreds million years after start of solar system formation. These regions, now sampled by some mantle plumes (e.g., Iceland, Eifel) preserved their volatile load, as indicated by extinct and extant radioactivity systems. The abundance of volatile elements in the mantle is still not well known. Different approaches, such as high pressure experimental petrology, noble gas geochemistry, modelling, resulted in somewhat contrasted estimates, varying over one order of magnitude for water. Comparative planetology, that is, the study of volatiles on the Moon, Venus, Mars, Vesta, will shed light on the sources and strengths of these elements in the

Volatile composition of some Brazilian fruits: umbu-caja (Spondias citherea), camu-camu (Myrciaria dubia), Araça-boi (Eugenia stipitata), and Cupuaçu (Theobroma grandiflorum).

Science.gov (United States)

Franco, M R; Shibamoto, T

2000-04-01

Twenty-one volatile compounds were identified for the first time by GC-MS in umbu-caja and in camu-camu, plus 30 volatile compounds were identified in araça-boi samples. Terpenic compounds predominated among the volatile compounds in these fruit samples, with the major compounds being identified as cis-beta-ocimene and caryophyllene in the northeastern fruit; alpha-pinene and d-limonene were the most abundant volatile compounds in the headspace of the Amazonian fruit camu-camu. Sesquiterpenes were the most abundant compounds in the araça-boi sample, with germacrene D presenting a higher relative percentage. The chemical class of esters predominated in the cupuaçu sample. Ethyl butyrate and hexanoate were the major compounds in the headspace of this Amazonian fruit.

Polyphenols and Volatiles in Fruits of Two Sour Cherry Cultivars, Some Berry Fruits and Their Jams

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Branka Levaj

2010-01-01

Full Text Available This paper reports about the content of polyphenols and volatiles in fresh fruits of two sour cherry cultivars (Marasca and Oblačinska, some berry fruits (strawberry Maya, raspberry Willamette and wild blueberry and the corresponding low sugar jams. Phenolic compounds (hydroxybenzoic and hydroxycinnamic acids, flavan 3-ols and flavonols were determined by high-performance liquid chromatography (HPLC. Those found in the fruits were also found in the jams. Jams contained lower amounts of polyphenols than fresh fuits, but their overall retention in jams was relatively high. Among fruits, sour cherry Marasca had the highest level of polyphenols, while sour cherry Marasca jam and raspberry Willamette jam had the highest level of polyphenols among jams. The major flavonoid in all investigated fruits, except in sour cherry Oblačinska, was (–-epicatechin. Sour cherry Marasca had the highest level of (–-epicatechin (95.75 mg/kg, and it also contained very high amounts of flavonols, derivatives of quercetin and kaempferol. Hydroxybenzoic acids (HBAs were not found in sour cherries Marasca and Oblačinska, but were found in berry fruits and jams. Phenolic compound (+-gallocatechin was found only in Marasca fruit and jam. Ellagic acid was found in the highest concentration in raspberry Willamette fruit and jam. Hydroxycinnamic acids (HCAs were found in all the investigated fruits, with the exception of a derivative of ferulic acid, which was not found in strawberry. Derivatives of caffeic, p-coumaric and chlorogenic acids were found in all the investigated fruits, with chlorogenic acid being the most abundant, especially in sour cherry Marasca. Volatiles were determined by gas chromatography (GC and expressed as the peak area of the identified compounds. All investigated volatiles of fresh fruit were also determined in the related jams with relatively high retention. Sour cherries Marasca and Oblačinska contained the same volatile compounds, but

FORMATION OF THE SHORT-LIVED RADIONUCLIDE 36Cl IN THE PROTOPLANETARY DISK DURING LATE-STAGE IRRADIATION OF A VOLATILE-RICH RESERVOIR

International Nuclear Information System (INIS)

Jacobsen, Benjamin; Yin Qingzhu; Matzel, Jennifer; Hutcheon, Ian D.; Ramon, Erick C.; Weber, Peter K.; Krot, Alexander N.; Nagashima, Kazuhide; Ishii, Hope A.; Ciesla, Fred J.

2011-01-01

Short-lived radionuclides (SLRs) in the early solar system provide fundamental insight into protoplanetary disk evolution. We measured the 36 Cl- 36 S-isotope abundance in wadalite ( 36 Cl (τ 1/2 ∼ 3 x 10 5 yr) in the early solar system. Its presence, initial abundance, and the noticeable decoupling from 26 Al raise serious questions about the origin of SLRs. The inferred initial 36 Cl abundance for wadalite, corresponding to a 36 Cl/ 35 Cl ratio of (1.81 ± 0.13) x 10 -5 , is the highest 36 Cl abundance ever reported in any early solar system material. The high level of 36 Cl in wadalite and the absence of 26 Al ( 26 Al/ 27 Al ≤ 3.9 x 10 -6 ) in co-existing grossular (1) unequivocally support the production of 36 Cl by late-stage solar energetic particle irradiation in the protoplanetary disk and (2) indicates that the production of 36 Cl, recorded by wadalite, is unrelated to the origin of 26 Al and other SLRs ( 10 Be, 53 Mn) recorded by primary minerals of CAIs and chondrules. We infer that 36 Cl was largely produced by irradiation of a volatile-rich reservoir in an optically thin protoplanetary disk adjacent to the region in which the CV chondrite parent asteroid accreted while the Sun was a weak T Tauri star. Subsequently, 36 Cl accreted into the Allende CV chondrite together with condensed water ices.

Volatiles of Helichrysum italicum (Roth) G. Don from Croatia.

Science.gov (United States)

Zeljković, Sanja Ćavar; Šolić, Marija Edita; Maksimović, Milka

2015-01-01

Helichrysum italicum (Roth) G. Don is a flowering plant of the family Asteraceae. It is rich in oil that is used for different medicinal purposes and in fragrance industry. Volatile profile of four populations of H. italicum, collected from natural habitat in Dalmatia (Croatia), was analysed by capillary GC-MS. Sample from BraČ Island had α-trans-bergamotene (10.2%) and β-acoradiene (10.1%) as the majors, whereas sample collected on Biokovo Mt. was rich in neryl acetate (8.1%). β-Acoradiene was also the main constituent of sample collected near Tijarica, whereas rosifoliol (8.5%) was the most abundant constituent in sample collected near Makarska. Presented results show the influence of environmental conditions on chemical differentiation of the volatiles of H. italicum from Croatia.

Energetic-particle abundances in impulsive solar flares

Science.gov (United States)

Reames, D. V.; Cane, H. V.; Von Rosenvinge, T. T.

1990-01-01

The abundances of elements and of He-3 in 90 solar electron events have been examined. It is found that the events fall into two distinct groups based upon their F/C ratio. Events in the F-rich group frequently have high He-3/He-4 ratios and are associated with type III and type V radio bursts in the parent flare. The F-poor events are associated with type IV bursts. These results on individual events support the conclusions of earlier work done with daily-averaged abundances.

Aerosols in the tropical and subtropical UT/LS: in-situ measurements of submicron particle abundance and volatility

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S. Borrmann

2010-06-01

Full Text Available Processes occurring in the tropical upper troposphere (UT, the Tropical Transition Layer (TTL, and the lower stratosphere (LS are of importance for the global climate, for stratospheric dynamics and air chemistry, and for their influence on the global distribution of water vapour, trace gases and aerosols. In this contribution we present aerosol and trace gas (in-situ measurements from the tropical UT/LS over Southern Brazil, Northern Australia, and West Africa. The instruments were operated on board of the Russian high altitude research aircraft M-55 "Geophysica" and the DLR Falcon-20 during the campaigns TROCCINOX (Araçatuba, Brazil, February 2005, SCOUT-O3 (Darwin, Australia, December 2005, and SCOUT-AMMA (Ouagadougou, Burkina Faso, August 2006. The data cover submicron particle number densities and volatility from the COndensation PArticle counting System (COPAS, as well as relevant trace gases like N₂O, ozone, and CO. We use these trace gas measurements to place the aerosol data into a broader atmospheric context. Also a juxtaposition of the submicron particle data with previous measurements over Costa Rica and other tropical locations between 1999 and 2007 (NASA DC-8 and NASA WB-57F is provided. The submicron particle number densities, as a function of altitude, were found to be remarkably constant in the tropical UT/LS altitude band for the two decades after 1987. Thus, a parameterisation suitable for models can be extracted from these measurements. Compared to the average levels in the period between 1987 and 2007 a slight increase of particle abundances was found for 2005/2006 at altitudes with potential temperatures, Θ, above 430 K. The origins of this increase are unknown except for increases measured during SCOUT-AMMA. Here the eruption of the Soufrière Hills volcano in the Caribbean caused elevated particle mixing ratios. The vertical profiles from Northern hemispheric mid-latitudes between 1999 and 2006 also are

The bouquet of grapevine (Vitis vinifera L. cv. Cabernet Sauvignon) flowers arises from the biosynthesis of sesquiterpene volatiles in pollen grains

Science.gov (United States)

Martin, Diane M.; Toub, Omid; Chiang, Angela; Lo, Bernard C.; Ohse, Sebastian; Lund, Steven T.; Bohlmann, Jörg

2009-01-01

Terpenoid volatiles are important information molecules that enable pollinators to locate flowers and may protect reproductive tissues against pathogens or herbivores. Inflorescences of grapevine (Vitis vinifera L.) are composed of tiny green flowers that produce an abundance of sesquiterpenoid volatiles. We demonstrate that male flower parts of grapevines are responsible for sesquiterpenoid floral scent formation. We describe temporal and spatial patterns of biosynthesis and release of floral volatiles throughout the blooming of V. vinifera L. cv. Cabernet Sauvignon. The biosynthesis of sesquiterpene volatiles, which are emitted with a light-dependent diurnal pattern early in the morning at prebloom and bloom, is localized to anthers and, more specifically, within the developing pollen grains. Valencene synthase (VvValCS) enzyme activity, which produces the major sesquiterpene volatiles of grapevine flowers, is present in anthers. VvValCS transcripts are most abundant in flowers at prebloom stages. Western blot analysis identified VvValCS protein in anthers, and in situ immunolabeling located VvValCS protein in pollen grains during bloom. Histochemical staining, as well as immunolabeling analysis by fluorescent microscopy and transmission electron microscopy, indicated that VvValCS localizes close to lipid bodies within the maturing microspore. PMID:19359488

Nonvolatile, semivolatile, or volatile: redefining volatile for volatile organic compounds.

Science.gov (United States)

Võ, Uyên-Uyén T; Morris, Michael P

2014-06-01

Although widely used in air quality regulatory frameworks, the term "volatile organic compound" (VOC) is poorly defined. Numerous standardized tests are currently used in regulations to determine VOC content (and thus volatility), but in many cases the tests do not agree with each other, nor do they always accurately represent actual evaporation rates under ambient conditions. The parameters (time, temperature, reference material, column polarity, etc.) used in the definitions and the associated test methods were created without a significant evaluation of volatilization characteristics in real world settings. Not only do these differences lead to varying VOC content results, but occasionally they conflict with one another. An ambient evaporation study of selected compounds and a few formulated products was conducted and the results were compared to several current VOC test methodologies: SCAQMD Method 313 (M313), ASTM Standard Test Method E 1868-10 (E1868), and US. EPA Reference Method 24 (M24). The ambient evaporation study showed a definite distinction between nonvolatile, semivolatile, and volatile compounds. Some low vapor pressure (LVP) solvents, currently considered exempt as VOCs by some methods, volatilize at ambient conditions nearly as rapidly as the traditional high-volatility solvents they are meant to replace. Conversely, bio-based and heavy hydrocarbons did not readily volatilize, though they often are calculated as VOCs in some traditional test methods. The study suggests that regulatory standards should be reevaluated to more accurately reflect real-world emission from the use of VOC containing products. The definition of VOC in current test methods may lead to regulations that exclude otherwise viable alternatives or allow substitutions of chemicals that may limit the environmental benefits sought in the regulation. A study was conducted to examine volatility of several compounds and a few formulated products under several current VOC test

Downwind evolution of the volatility and mixing state of near-road aerosols near a US interstate highway

Science.gov (United States)

Saha, Provat K.; Khlystov, Andrey; Grieshop, Andrew P.

2018-02-01

We present spatial measurements of particle volatility and mixing state at a site near a North Carolina interstate highway (I-40) applying several heating (thermodenuder; TD) experimental approaches. Measurements were conducted in summer 2015 and winter 2016 in a roadside trailer (10 m from road edge) and during downwind transects at different distances from the highway under favorable wind conditions using a mobile platform. Results show that the relative abundance of semi-volatile species (SVOCs) in ultrafine particles decreases with downwind distance, which is consistent with the dilution and mixing of traffic-sourced particles with background air and evaporation of semi-volatile species during downwind transport. An evaporation kinetics model was used to derive particle volatility distributions by fitting TD data. While the TD-derived distribution apportions about 20-30 % of particle mass as semi-volatile (SVOCs; effective saturation concentration, C∗ ≥ 1µm-3) at 10 m from the road edge, approximately 10 % of particle mass is attributed to SVOCs at 220 m, showing that the particle-phase semi-volatile fraction decreases with downwind distance. The relative abundance of semi-volatile material in the particle phase increased during winter. Downwind spatial gradients of the less volatile particle fraction (that remaining after heating at 180 °C) were strongly correlated with black carbon (BC). BC size distribution and mixing state measured using a single-particle soot photometer (SP2) at the roadside trailer showed that a large fraction (70-80 %) of BC particles were externally mixed. Heating experiments with a volatility tandem differential mobility analyzer (V-TDMA) also showed that the nonvolatile fraction in roadside aerosols is mostly externally mixed. V-TDMA measurements at different distances downwind from the highway indicate that the mixing state of roadside aerosols does not change significantly (e.g., BC mostly remains externally mixed) within a

A large source of low-volatility secondary organic aerosol

DEFF Research Database (Denmark)

Ehn, Mikael; Thornton, Joel A.; Kleist, Einhard

2014-01-01

radiation and by acting as cloud condensation nuclei. The quantitative assessment of such climate effects remains hampered by a number of factors, including an incomplete understanding of how biogenic VOCs contribute to the formation of atmospheric secondary organic aerosol. The growth of newly formed...... particles from sizes of less than three nanometres up to the sizes of cloud condensation nuclei (about one hundred nanometres) in many continental ecosystems requires abundant, essentially non-volatile organic vapours, but the sources and compositions of such vapours remain unknown. Here we investigate...... the oxidation of VOCs, in particular the terpene α-pinene, under atmospherically relevant conditions in chamber experiments. We find that a direct pathway leads from several biogenic VOCs, such as monoterpenes, to the formation of large amounts of extremely low-volatility vapours. These vapours form...

Pricing Volatility of Stock Returns with Volatile and Persistent Components

DEFF Research Database (Denmark)

Zhu, Jie

In this paper a two-component volatility model based on the component's first moment is introduced to describe the dynamic of speculative return volatility. The two components capture the volatile and persistent part of volatility respectively. Then the model is applied to 10 Asia-Pacific stock m......, a positive or risk-premium effect exists between return and the volatile component, yet the persistent component is not significantly priced for return dynamic process....... markets. Their in-mean effects on return are also tested. The empirical results show that the persistent component accounts much more for volatility dynamic process than the volatile component. However the volatile component is found to be a significant pricing factor of asset returns for most markets...

Carne caprina de animais mestiços: estudos do perfil aromático Goat meat of "mestiço" animals: volatile profile analysis

Directory of Open Access Journals (Sweden)

M. S. Madruga

2003-12-01

Full Text Available Análises do perfil aromático da carne caprina cozida de animais mestiços foram realizadas utilizando-se animais castrados e inteiros, abatidos com idades de 175, 220, 265 e 310 dias. O perfil aromático da carne caprina foi constituído por 108 voláteis, sendo que 69 foram positivamente identificados e 39 parcialmente caracterizados utilizando-se análises de CG-EM. O perfil aromático da carne caprina foi formado por hidrocarbonetos alifáticos e alicíclicos, aldeídos, compostos benzênicos, álcoois, cetonas, terpenóides, ésteres e compostos heterocíclicos sulfurados, hexadecanal, benzeno, heptano e octadecanal foram os voláteis que apresentaram os maiores índices de abundância relativa. Nas análises quantitativa e qualitativa observaram-se uma predominância de voláteis nos extratos de carne de caprinos castrados. O número total de voláteis e a abundância relativa das diferentes classes de compostos não foram claramente afetados pelo fator idade de abate.The volatile profile of cooked goat meat was analysed using meat from castrated and intact animals slaughtered at 175, 220, 265 and 310 days. A total of 108 volatiles was detected and from them 69 was identified and a further 39 were partially characterised by GC-MS. The volatile profile was composed by hydrocarbons aliphatic and alicyclic, aldehydes, benzenoid compounds, alcohols, ketones, terpenoids, esters and sulfur compounds. Hexadecanal, benzen, heptane and octadecanal were among the volatiles with highest relative abundance. In both qualitative and quantitative analyses extracts from castrated meat had higher production of volatiles. The total number and the relative abundance of different classes of compounds seemed not to be cleared affected by slaughter age factor.

Testing for Volatility Co-movement in Bivariate Stochastic Volatility Models

OpenAIRE

Chen, Jinghui; Kobayashi, Masahito; McAleer, Michael

2017-01-01

markdownabstractThe paper considers the problem of volatility co-movement, namely as to whether two financial returns have perfectly correlated common volatility process, in the framework of multivariate stochastic volatility models and proposes a test which checks the volatility co-movement. The proposed test is a stochastic volatility version of the co-movement test proposed by Engle and Susmel (1993), who investigated whether international equity markets have volatility co-movement using t...

Oil and stock market volatility: A multivariate stochastic volatility perspective

International Nuclear Information System (INIS)

Vo, Minh

2011-01-01

This paper models the volatility of stock and oil futures markets using the multivariate stochastic volatility structure in an attempt to extract information intertwined in both markets for risk prediction. It offers four major findings. First, the stock and oil futures prices are inter-related. Their correlation follows a time-varying dynamic process and tends to increase when the markets are more volatile. Second, conditioned on the past information, the volatility in each market is very persistent, i.e., it varies in a predictable manner. Third, there is inter-market dependence in volatility. Innovations that hit either market can affect the volatility in the other market. In other words, conditioned on the persistence and the past volatility in their respective markets, the past volatility of the stock (oil futures) market also has predictive power over the future volatility of the oil futures (stock) market. Finally, the model produces more accurate Value-at-Risk estimates than other benchmarks commonly used in the financial industry. - Research Highlights: → This paper models the volatility of stock and oil futures markets using the multivariate stochastic volatility model. → The correlation between the two markets follows a time-varying dynamic process which tends to increase when the markets are more volatile. → The volatility in each market is very persistent. → Innovations that hit either market can affect the volatility in the other market. → The model produces more accurate Value-at-Risk estimates than other benchmarks commonly used in the financial industry.

Pricing Volatility of Stock Returns with Volatile and Persistent Components

DEFF Research Database (Denmark)

Zhu, Jie

2009-01-01

This paper introduces a two-component volatility model based on first moments of both components to describe the dynamics of speculative return volatility. The two components capture the volatile and the persistent part of volatility, respectively. The model is applied to 10 Asia-Pacific stock ma...... markets. A positive or risk-premium effect exists between the return and the volatile component, yet the persistent component is not significantly priced for the return dynamic process....... markets. Their in-mean effects on returns are tested. The empirical results show that the persistent component is much more important for the volatility dynamic process than is the volatile component. However, the volatile component is found to be a significant pricing factor of asset returns for most...

Volatility in energy prices

International Nuclear Information System (INIS)

Duffie, D.

1999-01-01

This chapter with 58 references reviews the modelling and empirical behaviour of volatility in energy prices. Constant volatility and stochastic volatility are discussed. Markovian models of stochastic volatility are described and the different classes of Markovian stochastic volatility model are examined including auto-regressive volatility, option implied and forecasted volatility, Garch volatility, Egarch volatility, multivariate Garch volatility, and stochastic volatility and dynamic hedging policies. Other volatility models and option hedging are considered. The performance of several stochastic volatility models as applied to heating oil, light oil, natural gas, electricity and light crude oil are compared

Identification and Quantification of Oxidoselina-1,3,7(11)-Trien-8-One and Cyanidin-3-Glucoside as One of the Major Volatile and Non-Volatile Low-Molecular-Weight Constituents in Pitanga Pulp.

Science.gov (United States)

Josino Soares, Denise; Pignitter, Marc; Ehrnhöfer-Ressler, Miriam Margit; Walker, Jessica; Montenegro Brasil, Isabella; Somoza, Veronika

2015-01-01

The pulp of pitanga (Eugenia uniflora L.) is used to prepare pitanga juice. However, there are no reports on the identification and quantification of the main constituents in pitanga pulp. The aim of this study was to identify and quantify the major volatile and non-volatile low-molecular-weight constituents of the pulp. Isolation of volatile compounds was performed by solvent-assisted flavor evaporation technique. Characterization of the main volatile and non-volatile constituents was performed by GC-MS, LC-MS and NMR spectroscopy. For quantitative measurements, the main volatile compound needed to be isolated from pitanga pulp to obtain a commercially not available reference standard. Cyanidin-3-glucoside was determined as one of the most abundant non-volatile pulp compound yielding 53.8% of the sum of the intensities of all ions detected by LC-MS. Quantification of cyanidin-3-glucoside in pitanga pulp resulted in a concentration of 344 ± 66.4 μg/mL corresponding to 688 ± 133 μg/g dried pulp and 530 ± 102 μg/g fruit. For the volatile fraction, oxidoselina-1,3,7(11)-trien-8-one was identified as the main volatile pulp constituent (27.7% of the sum of the intensities of all ions detected by GC-MS), reaching a concentration of 89.0 ± 16.9 μg/mL corresponding to 1.34 ± 0.25 μg/g fresh pulp and 1.03 ± 0.19 μg/g fruit. The results provide quantitative evidence for the occurrence of an anthocyanin and an oxygenated sesquiterpene as one of the major volatile and non-volatile low-molecular-weight compounds in pitanga pulp.

Inefficient volatile loss from the Moon-forming disk: Reconciling the giant impact hypothesis and a wet Moon

Science.gov (United States)

Nakajima, Miki; Stevenson, David J.

2018-04-01

The Earth's Moon is thought to have formed from a circumterrestrial disk generated by a giant impact between the proto-Earth and an impactor approximately 4.5 billion years ago. Since this impact was energetic, the disk would have been hot (4000-6000 K) and partially vaporized (20-100% by mass). This formation process is thought to be responsible for the geochemical observation that the Moon is depleted in volatiles (e.g., K and Na). To explain this volatile depletion, some studies suggest the Moon-forming disk was rich in hydrogen, which was dissociated from water, and it escaped from the disk as a hydrodynamic wind accompanying heavier volatiles (hydrodynamic escape). This model predicts that the Moon should be significantly depleted in water, but this appears to contradict some of the recently measured lunar water abundances and D/H ratios that suggest that the Moon is more water-rich than previously thought. Alternatively, the Moon could have retained its water if the upper parts (low pressure regions) of the disk were dominated by heavier species because hydrogen would have had to diffuse out from the heavy-element rich disk, and therefore the escape rate would have been limited by this slow diffusion process (diffusion-limited escape). To identify which escape the disk would have experienced and to quantify volatiles loss from the disk, we compute the thermal structure of the Moon-forming disk considering various bulk water abundances (100-1000 ppm) and mid-plane disk temperatures (2500-4000 K). Assuming that the disk consists of silicate (SiO2 or Mg2SiO4) and water and that the disk is in the chemical equilibrium, our calculations show that the upper parts of the Moon-forming disk are dominated by heavy atoms or molecules (SiO and O at Tmid > 2500- 2800 K and H2O at Tmid lost water and hydrogen would have been small compared to the initial abundance assumed. This result indicates that the giant impact hypothesis can be consistent with the water-rich Moon

Volatile compound profile of sous-vide cooked lamb loins at different temperature-time combinations.

Science.gov (United States)

Roldán, Mar; Ruiz, Jorge; Del Pulgar, José Sánchez; Pérez-Palacios, Trinidad; Antequera, Teresa

2015-02-01

Lamb loins were subjected to sous-vide cooking at different combinations of temperature (60 and 80°C) and time (6 and 24h) to assess the effect on the volatile compound profile. Major chemical families in cooked samples were aliphatic hydrocarbons and aldehydes. The volatile compound profile in sous-vide cooked lamb loin was affected by the cooking temperature and time. Volatile compounds arising from lipid oxidation presented a high abundance in samples cooked at low or moderate cooking conditions (60°C for 6 and 24h, 80°C for 6h), while a more intense time and temperature combination (80°C for 24h) resulted on a higher concentration of volatile compounds arising from Strecker degradations of amino acids, as 2-methylpropanal and 3-methylbutanal. Therefore, sous-vide cooking at moderately high temperatures for long times would result in the formation of a stronger meaty flavor and roast notes in lamb meat. Copyright © 2014 Elsevier Ltd. All rights reserved.

Parent-Child Interaction Therapy: Enhancing Parent-Child Relationships

Directory of Open Access Journals (Sweden)

Anthony J. Urquiza

2012-07-01

Full Text Available Disruptive child behavior problems are common problems for parents and can be associated with serious delinquent behaviors and aggressive/violent behaviors in adolescence and adulthood. Parenting interventions to address disruptive child behavior problems has gained widespread acceptance. One of these parenting interventions is Parent-Child Interaction Therapy (PCIT. PCIT is a 14- to 20-week, founded on social learning and attachment theories, designed for children between 2 and 7 years of age with disruptive, or externalizing, behavior problems. This article will provide a brief review of the history of PCIT, a description of the basic components of PCIT, and an overview of recent developments that highlight the promise of PCIT with maltreating parent-child relationships, traumatized children, and in developing resilience in young children. In addressing the three basic treatment objectives for PCIT (i.e., reduction in child behavior problems, improving parenting skills, enhancing the quality of parent-child relationships, there is an abundance of research demonstrating very strong treatment effects and therefore, its value to the field. Recent research has also demonstrated the value of PCIT in reducing trauma symptoms in young children.

Determination of some volatile compounds in alcoholic beverage by headspace solid-phase microextraction gas chromatography - mass spectrometry

Science.gov (United States)

Schmutzer, G.; Avram, V.; Feher, I.; David, L.; Moldovan, Z.

2012-02-01

The volatile composition of alcoholic beverage was studied by headspace solid-phase microextraction (HSSPME) method and gas chromatography - mass spectrometry (GC-MS). Some volatile compounds, such as alcohols, esters, terpenes and other are mainly responsible for the flavor of fortified wines and their amounts specify the quality of the alcoholic beverages. From this perspective it is interesting to develop a rapid, selective and sensitive analytical method suitable for simultaneous quantification of the main molecules being responsible for the organoleptic characteristic of alcoholic beverages. Vermouth fortified drink was analyzed in order to characterize the volatile profile. Using the HS-SPME/GC-MS a number of twenty-six volatile compounds from a commercial market alcoholic beverage were identified. The most abundant compounds were m-thymol, o-thymol and eugenol, alongside of the ethyl ester compounds.

Volatility Discovery

DEFF Research Database (Denmark)

Dias, Gustavo Fruet; Scherrer, Cristina; Papailias, Fotis

The price discovery literature investigates how homogenous securities traded on different markets incorporate information into prices. We take this literature one step further and investigate how these markets contribute to stochastic volatility (volatility discovery). We formally show...... that the realized measures from homogenous securities share a fractional stochastic trend, which is a combination of the price and volatility discovery measures. Furthermore, we show that volatility discovery is associated with the way that market participants process information arrival (market sensitivity......). Finally, we compute volatility discovery for 30 actively traded stocks in the U.S. and report that Nyse and Arca dominate Nasdaq....

PERUBAHAN KOMPOSISI VOLATIL DAGING BUAH MANGGA "KENSINGTON PRIDE" SELAMA PEMASAKAN [Changes in Volatile Compound Composition of Kensington Pride Mango Pulp During Fruit Ripening

Directory of Open Access Journals (Sweden)

Herianus J.D Lalel

2003-08-01

Full Text Available Volatile compounds of ‘Kesington Pride’ mango produced from the pulp during fruit ripening were studied using headspace solid-phase microextraction (SPME as a sampling method and gas chromatography with a flame ionisation detector (GC-FID and gas chromatography mass spectrophotometry (GC-MS for analysis. Ethylene production and respiration reached a peak on the second and third day of ripening, respectively. Seventy-eight volatile compounds were identified from the pulp of ‘Kesington Pride’ mango; however, only 73 volatile compounds were present in notable amount. The most abundant group of volatile compounds was monoterpenes, accounting for abaout 44% of the total identified compounds, followed by sesquiterpenes (19%, aldehydes (11%,esters (10% aromatics (8%, alcohol (2%, ketones (2%, alkanes (1% and norisoprenoid (1%. -Terpinolene was the major compound during ripening. Except for -pinene, 3,7-dimethl-1,3,7-octatriene, 4-methl-1 (1-methylethylidene-cyclohexene, p-mentha-1,5,8-triene, aloocimene, the concentration of all other monoterpenes increased for the first six or eight days and decreased afterwards. All sesquiteroenes, p-cymene, p-cymen-9-ol,2-ethyl-1,4-dimethl benzene also increased during ripening and peaked on day four, six or eight of ripening. Ketones, aldehydes alkane and cis-3-hexenol, on the other hand, decreased during ripening. Ethanol, esters and norisoprenoid increased quite sharply at the end of ripening period.

Volatile characteristic of trace elements during microwave pyrolysis of oil shale

Energy Technology Data Exchange (ETDEWEB)

Bai, Jing-ru; Wang, Qing; Kong, Ling-wen; Bai, Zhang [Northeast Dianli Univ., Jilin (China). Engineering Research Centre

2013-07-01

Oil shale is abundant in the world. Today, the industry of oil shale retorting for producing shale oil is developing owing to high price of oil in the world. In order to study migratory behavior of trace elements in oil shale at microwave pyrolysis, tests were performed in laboratory with oil shale of the Huadian deposit of China at different powers from 400 to 700 W. The trace elements As, Cd, Hg, Mo, Pb, Se, Cr, Cu, Ni, V, Zn, Ba, Co, Mn present in oil shale and shale char were determined by the inductively coupled plasma-mass spectrometry (ICP-MS). By comparing the content of trace elements in oil shale and shale char, distribution characteristics of trace elements at retorting were studied. The overall trends of volatile ratio of trace elements are ascending with higher microwave power and higher than the conventional pyrolysis. The differences in the volatile ratio indicate that the trace elements investigated are bound with the oil shale kerogen and its mineral matter in different manner. So Float-sink experiments (FSE) were performed on oil shale. Huadian oil shale has more included mineral. The volatilization of organic matter is not the main reason for the volatilization of trace elements in oil shale. The trace elements combined with the mineral elements may be also certain volatility.

SILICON AND OXYGEN ABUNDANCES IN PLANET-HOST STARS

International Nuclear Information System (INIS)

Brugamyer, Erik; Dodson-Robinson, Sarah E.; Cochran, William D.; Sneden, Christopher

2011-01-01

The positive correlation between planet detection rate and host star iron abundance lends strong support to the core accretion theory of planet formation. However, iron is not the most significant mass contributor to the cores of giant planets. Since giant planet cores are thought to grow from silicate grains with icy mantles, the likelihood of gas giant formation should depend heavily on the oxygen and silicon abundance of the planet formation environment. Here we compare the silicon and oxygen abundances of a set of 76 planet hosts and a control sample of 80 metal-rich stars without any known giant planets. Our new, independent analysis was conducted using high resolution, high signal-to-noise data obtained at McDonald Observatory. Because we do not wish to simply reproduce the known planet-metallicity correlation, we have devised a statistical method for matching the underlying [Fe/H] distributions of our two sets of stars. We find a 99% probability that planet detection rate depends on the silicon abundance of the host star, over and above the observed planet-metallicity correlation. We do not detect any such correlation for oxygen. Our results would thus seem to suggest that grain nucleation, rather than subsequent icy mantle growth, is the important limiting factor in forming giant planets via core accretion. Based on our results and interpretation, we predict that planet detection should correlate with host star abundance for refractory elements responsible for grain nucleation and that no such trends should exist for the most abundant volatile elements responsible for icy mantle growth.

Level Shifts in Volatility and the Implied-Realized Volatility Relation

DEFF Research Database (Denmark)

Christensen, Bent Jesper; de Magistris, Paolo Santucci

We propose a simple model in which realized stock market return volatility and implied volatility backed out of option prices are subject to common level shifts corresponding to movements between bull and bear markets. The model is estimated using the Kalman filter in a generalization to the mult......We propose a simple model in which realized stock market return volatility and implied volatility backed out of option prices are subject to common level shifts corresponding to movements between bull and bear markets. The model is estimated using the Kalman filter in a generalization...... to the multivariate case of the univariate level shift technique by Lu and Perron (2008). An application to the S&P500 index and a simulation experiment show that the recently documented empirical properties of strong persistence in volatility and forecastability of future realized volatility from current implied...... volatility, which have been interpreted as long memory (or fractional integration) in volatility and fractional cointegration between implied and realized volatility, are accounted for by occasional common level shifts....

Testing for Volatility Co-movement in Bivariate Stochastic Volatility Models

NARCIS (Netherlands)

J. Chen (Jinghui); M. Kobayashi (Masahito); M.J. McAleer (Michael)

2017-01-01

markdownabstractThe paper considers the problem of volatility co-movement, namely as to whether two financial returns have perfectly correlated common volatility process, in the framework of multivariate stochastic volatility models and proposes a test which checks the volatility co-movement. The

Comparative Analysis of Flower Volatiles from Nine Citrus at Three Blooming Stages

Directory of Open Access Journals (Sweden)

Muhammad Azam

2013-11-01

Full Text Available Volatiles from flowers at three blooming stages of nine citrus cultivars were analyzed by headspace-solid phase microextraction (HS-SPME-GC-MS. Up to 110 volatiles were detected, with 42 tentatively identified from citrus flowers for the first time. Highest amounts of volatiles were present in fully opened flowers of most citrus, except for pomelos. All cultivars were characterized by a high percentage of either oxygenated monoterpenes or monoterpene hydrocarbons, and the presence of a high percentage of nitrogen containing compounds was also observed. Flower volatiles varied qualitatively and quantitatively among citrus types during blooming. Limonene was the most abundant flower volatile only in citrons; α-citral and β-citral ranked 2nd and 3rd only for Bergamot, and unopened flowers of Ponkan had a higher amount of linalool and β-pinene while much lower amount of γ-terpinene and p-cymene than Satsuma. Taking the average of all cultivars, linalool and limonene were the top two volatiles for all blooming stages; β-pinene ranked 3rd in unopened flowers, while indole ranked 3rd for half opened and fully opened flower volatiles. As flowers bloomed, methyl anthranilate increased while 2-hexenal and p-cymene decreased. In some cases, a volatile could be high in both unopened and fully opened flowers but low in half opened ones. Through multivariate analysis, the nine citrus cultivars were clustered into three groups, consistent with the three true citrus types. Furthermore, an influence of blooming stages on clustering was observed, especially with hybrids Satsuma and Huyou. Altogether, it was suggested that flower volatiles can be suitable markers for revealing the genetic relationships between citrus cultivars but the same blooming stage needs to be strictly controlled.

Volatilization: a soil degassing coefficient for iodine

International Nuclear Information System (INIS)

Sheppard, M.I.; Thibault, D.H.; Smith, P.A.; Hawkins, J.L.

1994-01-01

Iodine, an element essential to some animals, is ubiquitous in the biosphere. Unlike other metallic elements, molecular I is volatile, and other inorganic species present in aerated soils, such as I - and IO 3 - , may also volatilize as hydrides, hydrogen iodide (HI), or hydrogen iodates (HIO 3 , HIO 4 ). Methyl iodide has been measured in soils, and it is likely evolved from soils and plants. The long-lived radioisotope 129 I is abundant in nuclear wastes, and its high solubility in groundwater makes it an important element in the performance assessment of underground disposal facilities. Overestimates of soil I residence half-times by traditional foodchain models may be due to underestimation of volatilization. Field and lysimeter experiments over a 3-year period, and direct trapping experiments in the laboratory are reported. The results, combined with values from the literature, indicate the soil I degassing coefficient for a wide range of soil types, vegetated and bare, wet and dry, is lognormally distributed with a geometric mean of 2.1 x 10 -2 year -1 , a range of 1.8 x 10 -4 to 3.1 year -1 and a geometric standard deviation of 3.0. The results of a biosphere model simulation including degassing reduces soil I concentrations fivefold and increases air concentrations 25-fold at steady state, compared to simulations without degassing. (author)

Volatile Components from Old Plum Brandies

Directory of Open Access Journals (Sweden)

Ninoslav Nikićević

2005-01-01

Full Text Available Gas chromatography and GC/MS methods were used to detect volatile components of three home-made natural old plum brandy samples and one sample of industrially-produced plum brandy. Gas chromatography and gas chromatography-mass spectrometric analysis of this extracts led to the identification of 99 components, including 46 esters, 7 hydrocarbons (alkanes and alkenes, 3 aldehydes, 9 alcohols, 1 lactone, 1 ketone, 8 acetals, 14 terpenes, 8 acids and 2 phenols. Ethyl esters of C8–C18 acids were the most abundant in all samples. In addition, the content of methanol, ethanol and higher alcohols C3–C5 was determined.

Identification and Quantification of Oxidoselina-1,3,7(11-Trien-8-One and Cyanidin-3-Glucoside as One of the Major Volatile and Non-Volatile Low-Molecular-Weight Constituents in Pitanga Pulp.

Directory of Open Access Journals (Sweden)

Denise Josino Soares

Full Text Available The pulp of pitanga (Eugenia uniflora L. is used to prepare pitanga juice. However, there are no reports on the identification and quantification of the main constituents in pitanga pulp. The aim of this study was to identify and quantify the major volatile and non-volatile low-molecular-weight constituents of the pulp. Isolation of volatile compounds was performed by solvent-assisted flavor evaporation technique. Characterization of the main volatile and non-volatile constituents was performed by GC-MS, LC-MS and NMR spectroscopy. For quantitative measurements, the main volatile compound needed to be isolated from pitanga pulp to obtain a commercially not available reference standard. Cyanidin-3-glucoside was determined as one of the most abundant non-volatile pulp compound yielding 53.8% of the sum of the intensities of all ions detected by LC-MS. Quantification of cyanidin-3-glucoside in pitanga pulp resulted in a concentration of 344 ± 66.4 μg/mL corresponding to 688 ± 133 μg/g dried pulp and 530 ± 102 μg/g fruit. For the volatile fraction, oxidoselina-1,3,7(11-trien-8-one was identified as the main volatile pulp constituent (27.7% of the sum of the intensities of all ions detected by GC-MS, reaching a concentration of 89.0 ± 16.9 μg/mL corresponding to 1.34 ± 0.25 μg/g fresh pulp and 1.03 ± 0.19 μg/g fruit. The results provide quantitative evidence for the occurrence of an anthocyanin and an oxygenated sesquiterpene as one of the major volatile and non-volatile low-molecular-weight compounds in pitanga pulp.

Hollows on Mercury: MESSENGER evidence for geologically recent volatile-related activity.

Science.gov (United States)

Blewett, David T; Chabot, Nancy L; Denevi, Brett W; Ernst, Carolyn M; Head, James W; Izenberg, Noam R; Murchie, Scott L; Solomon, Sean C; Nittler, Larry R; McCoy, Timothy J; Xiao, Zhiyong; Baker, David M H; Fassett, Caleb I; Braden, Sarah E; Oberst, Jürgen; Scholten, Frank; Preusker, Frank; Hurwitz, Debra M

2011-09-30

High-resolution images of Mercury's surface from orbit reveal that many bright deposits within impact craters exhibit fresh-appearing, irregular, shallow, rimless depressions. The depressions, or hollows, range from tens of meters to a few kilometers across, and many have high-reflectance interiors and halos. The host rocks, which are associated with crater central peaks, peak rings, floors, and walls, are interpreted to have been excavated from depth by the crater-forming process. The most likely formation mechanisms for the hollows involve recent loss of volatiles through some combination of sublimation, space weathering, outgassing, or pyroclastic volcanism. These features support the inference that Mercury's interior contains higher abundances of volatile materials than predicted by most scenarios for the formation of the solar system's innermost planet.

Early accretion of water and volatile elements to the inner Solar System: evidence from angrites.

Science.gov (United States)

Sarafian, Adam R; Hauri, Erik H; McCubbin, Francis M; Lapen, Thomas J; Berger, Eve L; Nielsen, Sune G; Marschall, Horst R; Gaetani, Glenn A; Righter, Kevin; Sarafian, Emily

2017-05-28

Inner Solar System bodies are depleted in volatile elements relative to chondrite meteorites, yet the source(s) and mechanism(s) of volatile-element depletion and/or enrichment are poorly constrained. The timing, mechanisms and quantities of volatile elements present in the early inner Solar System have vast implications for diverse processes, from planetary differentiation to the emergence of life. We report major, trace and volatile-element contents of a glass bead derived from the D'Orbigny angrite, the hydrogen isotopic composition of this glass bead and that of coexisting olivine and silicophosphates, and the 207 Pb- 206 Pb age of the silicophosphates, 4568 ± 20 Ma. We use volatile saturation models to demonstrate that the angrite parent body must have been a major body in the early inner Solar System. We further show via mixing calculations that all inner Solar System bodies accreted volatile elements with carbonaceous chondrite H and N isotope signatures extremely early in Solar System history. Only a small portion (if any) of comets and gaseous nebular H species contributed to the volatile content of the inner Solar System bodies.This article is part of the themed issue 'The origin, history and role of water in the evolution of the inner Solar System'. © 2017 The Author(s).

Relationships between Microbial Activities and Subduction-related Outgassing and Volatile Flux at Aleutian Arc Volcanoes

Science.gov (United States)

Miller, H.; Lopez, T. M.; Fischer, T. P.; Schrenk, M. O.

2016-12-01

Subduction-related processes, including the movement and alteration of carbon compounds, are an important component of global geochemical cycles. Actively degassing volcanoes of the Aleutian Island arc offer interesting opportunities to not only characterize the composition and abundance of volatiles, but also to identify the origin of the discharging gases (e.g. mantle, organic matter, or carbonates). Taking this approach a step further, microbial activities in and around volcanic fumarole areas may impact the composition and flux of reduced volcanic gases, either through their modification or their assimilation into fixed biomass. Microbiological studies of these systems can be used to develop predictive models to complement those based upon geochemical data while providing greater understanding of the causal relationships between microbial populations and their environment, and ultimately refine estimates of volcanic outgassing. Coupled fumarole soil and gas samples were collected from several Aleutian Island volcanoes in 2015 (Gareloi, Kanaga, Kiska, Little Sitkin) and 2016 (Okmok, Resheschnoi). DNA was extracted from the soil and used to describe microbial community composition, while gas samples were analyzed through chromatography and mass spectrometry. Preliminary data suggests a relationship between the abundance of specific groups of prokaryotes known to metabolize reduced gases, such as sulfur-oxidizers and methanotrophs, and the abundances of the degassing volatiles, including sulfur dioxide and methane. Ongoing studies aimed at investigating the relationship between the genomic composition of the fumarolic microbial community and the physical and chemical properties of the soil (i.e. mineralogy, bulk geochemistry, nutrient concentration, gas flux, and environmental measurements) are underway. These data will be used to evaluate the potential for microbial communities to remove volcanic carbon and store it as biomass, or to modify the volatile carbon

Angrites: A Volatile-rich Variety of Asteroidal Basalt (Except for Alkalis and Gallium!)

Science.gov (United States)

Warren, P. H.; Kallemeyn, G. W.

1995-09-01

Angrites are commonly viewed as extremely volatile-depleted, and a related notion is that they formed by differentiation of a very CAI-rich material [e.g., 1]. Partial melting experiments reportedly reproduce the bulk compositions (although not fassaite-rich mineralogy) of angrites with Allende as starting material [2], but highly CAI-rich parent materials are difficult to reconcile with isotopic and REE data [3,4]. Mittlefehldt and Lindstrom [5] inferred from the low Na/Al ratios of angrites that outgassing, and thus primordial magmatism, was more intense on their parent body than on the eucrite parent asteroid. Of seven elements that (a) have been adequately determined in angrites, and (b) are far more volatile (solar-nebula 50% condensation T [6] = 690-430 K) than the alkalis (1000-910 K), four are enriched, and none is significantly depleted, in average angrite compared to average eucrite or low-Ti mare basalt (Figure). Gallium, which is of intermediate volatility (830 K), is depleted to roughly the same extent as Na and K. Results for A881371 [3] are incomplete (Zn, 6 micrograms/g, is near INAA detection limit), but even based only on AdoR and the two LEW angrites, this pattern seems firmly established. Apparent gas cavities in A881371 [7] also suggest that volatiles are far from uniformly depleted. The only elements known to be depleted, as volatiles, by clearly significant factors in angrites versus eucrites or lunar basalts, are alkalis plus gallium. Besides being moderately volatile, a noteworthy characteristic shared among Ga and alkalis (and not shared with elements such as Br, Se, and Zn) is that these elements probably tend to partition into crustal feldspar during gross differentiation of small (low-pressure) bodies. If gallium + alkalis were depleted by a single process starting from "normal" chondritic material, that process would seem to require selective exposure of a feldspar-enriched region (i.e., crust) to extremely high temperature. Igneous

Range-based volatility, expected stock returns, and the low volatility anomaly

Science.gov (United States)

2017-01-01

One of the foundations of financial economics is the idea that rational investors will discount stocks with more risk (volatility), which will result in a positive relation between risk and future returns. However, the empirical evidence is mixed when determining how volatility is related to future returns. In this paper, we examine this relation using a range-based measure of volatility, which is shown to be theoretically, numerically, and empirically superior to other measures of volatility. In a variety of tests, we find that range-based volatility is negatively associated with expected stock returns. These results are robust to time-series multifactor models as well as cross-sectional tests. Our findings contribute to the debate about the direction of the relationship between risk and return and confirm the presence of the low volatility anomaly, or the anomalous finding that low volatility stocks outperform high volatility stocks. In other tests, we find that the lower returns associated with range-based volatility are driven by stocks with lottery-like characteristics. PMID:29190652

Range-based volatility, expected stock returns, and the low volatility anomaly.

Science.gov (United States)

Blau, Benjamin M; Whitby, Ryan J

2017-01-01

One of the foundations of financial economics is the idea that rational investors will discount stocks with more risk (volatility), which will result in a positive relation between risk and future returns. However, the empirical evidence is mixed when determining how volatility is related to future returns. In this paper, we examine this relation using a range-based measure of volatility, which is shown to be theoretically, numerically, and empirically superior to other measures of volatility. In a variety of tests, we find that range-based volatility is negatively associated with expected stock returns. These results are robust to time-series multifactor models as well as cross-sectional tests. Our findings contribute to the debate about the direction of the relationship between risk and return and confirm the presence of the low volatility anomaly, or the anomalous finding that low volatility stocks outperform high volatility stocks. In other tests, we find that the lower returns associated with range-based volatility are driven by stocks with lottery-like characteristics.

Range-based volatility, expected stock returns, and the low volatility anomaly.

Directory of Open Access Journals (Sweden)

Benjamin M Blau

Full Text Available One of the foundations of financial economics is the idea that rational investors will discount stocks with more risk (volatility, which will result in a positive relation between risk and future returns. However, the empirical evidence is mixed when determining how volatility is related to future returns. In this paper, we examine this relation using a range-based measure of volatility, which is shown to be theoretically, numerically, and empirically superior to other measures of volatility. In a variety of tests, we find that range-based volatility is negatively associated with expected stock returns. These results are robust to time-series multifactor models as well as cross-sectional tests. Our findings contribute to the debate about the direction of the relationship between risk and return and confirm the presence of the low volatility anomaly, or the anomalous finding that low volatility stocks outperform high volatility stocks. In other tests, we find that the lower returns associated with range-based volatility are driven by stocks with lottery-like characteristics.

Origin of the earth's moon: constraints from alkali volatile trace elements

International Nuclear Information System (INIS)

Kreutzberger, M.E.; Drake, M.J.; Jones, J.H.

1986-01-01

Although the Moon is depleted in volatile elements compared to the Earth, these depletions are not in accord with simple volatility. For example, the Cs/Rb ratios of the Earth and Moon inferred from basalts are approximately one seventh and one half of the CI ratio, respectively. Volatility considerations alone predict that the lunar Cs/Rb ratio should be equal to or lower than the terrestrial ratio if the Moon was derived entirely from Earth mantle material. Thus hypotheses such as rotational fission which invoke derivation of lunar material entirely from the Earth's mantle may be excluded. The collisional ejection hypothesis of lunar origin requires at least 18% of lunar material to be derived from a projectile with dehydrated CI composition to match the lunar Cs/Rb ratio, and 25% to 50% to match both the lunar Cs/Rb ratio and absolute concentrations of Cs and Rb. It remains to be demonstrated that this relatively large contribution of projectile material is consistent with other elemental abundances and element ratios in the Moon. (author)

The Law of Element Abundance Relationships in Igneous Rocks Petrogenetically Associated with Fractional Crystallization

Institute of Scientific and Technical Information of China (English)

汪云亮; 王旺章

1991-01-01

Reported in this paper are:1)the law of element abundance relationships:element abun-dances are of power function with each other in an igneous rock petrogenetically associated with fractional crystallization,2)deduction of the law and relevant parameters:abundance relationship constant(a°) and phase constant? from Henry's law and the law of mass conservation,3)the data basis and evidence of the law of element abundance relationships,4)establishment of the equa-bions for element abundance relationships in igneous rocks formed from the same parental magma during the same fractional crystallization stage ,and all measurable parameters involved in the equations.

Pricing Volatility Referenced Assets

Directory of Open Access Journals (Sweden)

Alan De Genaro Dario

2006-12-01

Full Text Available Volatility swaps are contingent claims on future realized volatility. Variance swaps are similar instruments on future realized variance, the square of future realized volatility. Unlike a plain vanilla option, whose volatility exposure is contaminated by its asset price dependence, volatility and variance swaps provide a pure exposure to volatility alone. This article discusses the risk-neutral valuation of volatility and variance swaps based on the framework outlined in the Heston (1993 stochastic volatility model. Additionally, the Heston (1993 model is calibrated for foreign currency options traded at BMF and its parameters are used to price swaps on volatility and variance of the BRL / USD exchange rate.

Control of postharvest Botrytis fruit rot of strawberry by volatile organic compounds of Candida intermedia.

Science.gov (United States)

Huang, R; Li, G Q; Zhang, J; Yang, L; Che, H J; Jiang, D H; Huang, H C

2011-07-01

A study was conducted to identify volatile organic compounds or volatiles produced by Candida intermedia strain C410 using gas chromatography-mass spectrometry, and to determine efficacy of the volatiles of C. intermedia in suppression of conidial germination and mycelial growth of Botrytis cinerea and control of Botrytis fruit rot of strawberry. Results showed that, among 49 volatiles (esters, alcohols, alkenes, alkanes, alkynes, organic acids, ketones, and aldehydes) identified from C. intermedia cultures on yeast extract peptone dextrose agar, two compounds, 1,3,5,7-cyclooctatetraene and 3-methyl-1-butanol, were the most abundant. Synthetic chemicals of 1,3,5,7-cyclooctatetraene; 3-methyl-1-butanol; 2-nonanone; pentanoic acid, 4-methyl-, ethyl ester; 3-methyl-1-butanol, acetate; acetic acid, pentyl ester; and hexanoic acid, ethyl ester were highly inhibitory to conidial germination and mycelial growth of B. cinerea. Inhibition of conidial germination and mycelial growth of B. cinerea by volatiles of C. intermedia was also observed. Meanwhile, results showed that incidence and severity of Botrytis fruit rot of strawberry was significantly (P intermedia cultures or C. intermedia-infested strawberry fruit. These results suggest that the volatiles of C. intermedia C410 are promising biofumigants for control of Botrytis fruit rot of strawberry.

Volatile and non-volatile/semi-volatile compounds and in vitro bioactive properties of Chilean Ulmo (Eucryphia cordifolia Cav.) honey.

Science.gov (United States)

Acevedo, Francisca; Torres, Paulina; Oomah, B Dave; de Alencar, Severino Matias; Massarioli, Adna Prado; Martín-Venegas, Raquel; Albarral-Ávila, Vicenta; Burgos-Díaz, César; Ferrer, Ruth; Rubilar, Mónica

2017-04-01

Ulmo honey originating from Eucryphia cordifolia tree, known locally in the Araucania region as the Ulmo tree is a natural product with valuable nutritional and medicinal qualities. It has been used in the Mapuche culture to treat infections. This study aimed to identify the volatile and non-volatile/semi-volatile compounds of Ulmo honey and elucidate its in vitro biological properties by evaluating its antioxidant, antibacterial, antiproliferative and hemolytic properties and cytotoxicity in Caco-2 cells. Headspace volatiles of Ulmo honey were isolated by solid-phase microextraction (SPME); non-volatiles/semi-volatiles were obtained by removing all saccharides with acidified water and the compounds were identified by GC/MS analysis. Ulmo honey volatiles consisted of 50 compounds predominated by 20 flavor components. Two of the volatile compounds, lyrame and anethol have never been reported before as honey compounds. The non-volatile/semi-volatile components of Ulmo honey comprised 27 compounds including 13 benzene derivatives accounting 75% of the total peak area. Ulmo honey exhibited weak antioxidant activity but strong antibacterial activity particularly against gram-negative bacteria and methicillin-resistant Staphylococcus aureus (MRSA), the main strain involved in wounds and skin infections. At concentrations >0.5%, Ulmo honey reduced Caco-2 cell viability, released lactate dehydrogenase (LDH) and increased reactive oxygen species (ROS) production in a dose dependent manner in the presence of foetal bovine serum (FBS). The wide array of volatile and non-volatile/semi-volatile constituents of Ulmo honey rich in benzene derivatives may partly account for its strong antibacterial and antiproliferative properties important for its therapeutic use. Our results indicate that Ulmo honey can potentially inhibit cancer growth at least partly by modulating oxidative stress. Copyright © 2017 Elsevier Ltd. All rights reserved.

Volatile composition and enantioselective analysis of chiral terpenoids of nine fruit and vegetable fibres resulting from juice industry by-products

OpenAIRE

Marsol i Vall, Alexis; Sgorbini, Barbara; Cagliero, Cecilia; Bicchi, Carlo; Eras i Joli, Jordi; Balcells Fluvià, Mercè

2017-01-01

Fruit and vegetable fibres resulting as by-products of the fruit juice industry have won popularity because they can be valorised as food ingredients. In this regard, bioactive compounds have already been studied but little attention has been paid to their remaining volatiles. Considering all the samples, 57 volatiles were identified. Composition greatly differed between citrus and noncitrus fibres. The former presented over 90% of terpenoids, with limonene being the most abundant and ranging...

Levels and source apportionment of volatile organic compounds in southwestern area of Mexico City

Energy Technology Data Exchange (ETDEWEB)

Rodolfo Sosa, E. [Centro de Ciencias de la Atmosfera, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, C.P. 04510, D.F. (Mexico); Humberto Bravo, A. [Centro de Ciencias de la Atmosfera, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, C.P. 04510, D.F. (Mexico)], E-mail: hbravo@servidor.unam.mx; Violeta Mugica, A. [Universidad Autonoma Metropolitana, Azcapotzalco, D.F. (Mexico); Pablo Sanchez, A. [Centro de Ciencias de la Atmosfera, Universidad Nacional Autonoma de Mexico, Circuito Exterior, Ciudad Universitaria, C.P. 04510, D.F. (Mexico); Emma Bueno, L. [Centro Nacional de Investigacion y Capacitacion Ambiental, Instituto Nacional de Ecologia (Mexico); Krupa, Sagar [Department of Plant Pathology, University of Minnesota, St. Paul, MN 55108 (United States)

2009-03-15

Thirteen volatile organic compounds (VOCs) were quantified at three sites in southwestern Mexico City from July 2000 to February 2001. High concentrations of different VOCs were found at a Gasoline refueling station (GS), a Condominium area (CA), and at University Center for Atmospheric Sciences (CAS). The most abundant VOCs at CA and CAS were propane, n-butane, toluene, acetylene and pentane. In comparison, at GS the most abundant were toluene, pentane, propane, n-butane, and acetylene. Benzene, a known carcinogenic compound had average levels of 28, 35 and 250 ppbC at CAS, CA, and GS respectively. The main contributing sources of the measured VOCs at CA and CAS were the handling and management of LP (Liquid Propane) gas, vehicle exhaust, asphalt works, and use of solvents. At GS almost all of the VOCs came from vehicle exhaust and fuel evaporation, although components of LP gas were also present. Based on the overall results possible abatement strategies are discussed. - Volatile organic compounds were quantified in order to perform their source apportionment in southwestern area of Mexico City.

Levels and source apportionment of volatile organic compounds in southwestern area of Mexico City

International Nuclear Information System (INIS)

Rodolfo Sosa, E.; Humberto Bravo, A.; Violeta Mugica, A.; Pablo Sanchez, A.; Emma Bueno, L.; Krupa, Sagar

2009-01-01

Thirteen volatile organic compounds (VOCs) were quantified at three sites in southwestern Mexico City from July 2000 to February 2001. High concentrations of different VOCs were found at a Gasoline refueling station (GS), a Condominium area (CA), and at University Center for Atmospheric Sciences (CAS). The most abundant VOCs at CA and CAS were propane, n-butane, toluene, acetylene and pentane. In comparison, at GS the most abundant were toluene, pentane, propane, n-butane, and acetylene. Benzene, a known carcinogenic compound had average levels of 28, 35 and 250 ppbC at CAS, CA, and GS respectively. The main contributing sources of the measured VOCs at CA and CAS were the handling and management of LP (Liquid Propane) gas, vehicle exhaust, asphalt works, and use of solvents. At GS almost all of the VOCs came from vehicle exhaust and fuel evaporation, although components of LP gas were also present. Based on the overall results possible abatement strategies are discussed. - Volatile organic compounds were quantified in order to perform their source apportionment in southwestern area of Mexico City

Iodine volatility

International Nuclear Information System (INIS)

Beahm, E.C.; Shockley, W.E.

1984-01-01

The ultimate aim of this program is to couple experimental aqueous iodine volatilities to a fission product release model. Iodine partition coefficients, for inorganic iodine, have been measured during hydrolysis and radiolysis. The hydrolysis experiments have illustrated the importance of reaction time on iodine volatility. However, radiolysis effects can override hydrolysis in determining iodine volatility. In addition, silver metal in radiolysis samples can react to form silver iodide accompanied by a decrease in iodine volatility. Experimental data are now being coupled to an iodine transport and release model that was developed in the Federal Republic of Germany

Flue-gas desulfurization gypsum effects on urea-degrading bacteria and ammonia volatilization from broiler litter.

Science.gov (United States)

Burt, Christopher D; Cabrera, Miguel L; Rothrock, Michael J; Kissel, D E

2017-08-01

A major concern of the broiler industry is the volatilization of ammonia (NH3) from the mixture of bedding material and broiler excretion that covers the floor of broiler houses. Gypsum has been proposed as a litter amendment to reduce NH3 volatilization, but reports of NH3 abatement vary among studies and the mechanism responsible for decreasing NH3 volatilization is not well understood. The goal of this study was to evaluate the effect of adding 20 or 40% flue-gas desulfurization gypsum (FGDG) to broiler litter on pH, electrical conductivity (EC), water potential, urea-degrading bacteria abundance, NH3 and carbon dioxide (CO2) evolution, and nitrogen (N) mineralization in several 21-d experiments. The addition of FGDG to broiler litter increased EC by 24 to 33% (P mineralization by 10 to 11% (P = 0.0001) as compared to litters not amended with FGDG. Furthermore, the addition of FGDG to broiler litter decreased NH3 volatilization by 18 to 28% (P litter pH values compared to un-amended litter (P litter with 20% FGDG can decrease NH3 volatilization and increase the fertlizer value of broiler litter. © 2017 Poultry Science Association Inc.

Parent Stars of Extrasolar Planets - XIV. Strong Evidence of Li Abundance Deficit

OpenAIRE

Gonzalez, Guillermo

2014-01-01

We report the results of our analysis of new high resolution spectra of 30 late-F to early-G dwarf field stars for the purpose of deriving their Li abundances. They were selected from the subsample of stars in the Valenti and Fischer compilation that are lacking detected planets. These new data serve to expand our comparison sample used to test whether stars with Doppler-detected giant planets display Li abundance anomalies. Our results continue to show that Li is deficient among stars with p...

Distribution of volatile composition in 'marion' ( rubus species hyb) blackberry pedigree.

Science.gov (United States)

Du, Xiaofen; Finn, Chad; Qian, Michael C

2010-02-10

The distribution of volatile constituents in ancestral genotypes of 'Marion' blackberry's pedigree was investigated over two growing seasons. Each genotype in the pedigree had a specific volatile composition. Red raspberry was dominated by norisoprenoids, lactones, and acids. 'Logan' and 'Olallie' also had a norisoprenoid dominance but at much lower concentrations. The concentration of norisoprenoids in other blackberry genotypes was significantly lower. Terpenes and furanones were predominant in wild 'Himalaya' blackberry, whereas terpenes were the major volatiles in 'Santiam'. 'Marion', a selection from 'Chehalem' and 'Olallie', contained almost all of the volatile compounds in its pedigree at moderate amount. The chiral isomeric ratios of 11 pairs of compounds were also studied. Strong chiral isomeric preference was observed for most of the chiral compounds, and each cultivar had its unique chiral isomeric distribution. An inherent pattern was observed for some volatile compounds in the 'Marion' pedigree. Raspberry and 'Logan' had a very high concentration of beta-ionone, but was reduced by half in 'Olallie' and by another half in 'Marion' as the crossing proceeded. A high content of linalool in 'Olallie' and a low content in 'Chehalem' resulted in a moderate content of linalool in their progeny 'Marion'. However, the concentration of furaneol in 'Marion' was higher than in its parents. A high content of (S)-linalool in 'Olallie' and a racemic content of (S)-,(R)-linalool in 'Chehalem' resulted in a preference for the (S)-form in 'Marion'.

Asymmetric Realized Volatility Risk

Directory of Open Access Journals (Sweden)

David E. Allen

2014-06-01

Full Text Available In this paper, we document that realized variation measures constructed from high-frequency returns reveal a large degree of volatility risk in stock and index returns, where we characterize volatility risk by the extent to which forecasting errors in realized volatility are substantive. Even though returns standardized by ex post quadratic variation measures are nearly Gaussian, this unpredictability brings considerably more uncertainty to the empirically relevant ex ante distribution of returns. Explicitly modeling this volatility risk is fundamental. We propose a dually asymmetric realized volatility model, which incorporates the fact that realized volatility series are systematically more volatile in high volatility periods. Returns in this framework display time varying volatility, skewness and kurtosis. We provide a detailed account of the empirical advantages of the model using data on the S&P 500 index and eight other indexes and stocks.

Distribution of volatile organic compounds over a semiconductor Industrial Park in Taiwan.

Science.gov (United States)

Chiu, Kong-Hwa; Wu, Ben-Zen; Chang, Chih-Chung; Sree, Usha; Lo, Jiunn-Guang

2005-02-15

This study examined volatile organic compounds (VOC) concentration in ambient air collected during the years 2000--2003 at several different locations of Hsinchu Science-based Industrial Park (HSIP) in Taiwan. A canister automated GC-MS system analyzed the volatile organics in ambient air grasp samples according to T0-15 method. Oxygenated volatiles were the most abundant VOC detected in HSIP followed by aromatics that are commonly used as solvents in the semiconductor industries. The major components measured in the ambient air are 2-propanol (29-135 ppbv), acetone (12-164 ppbv), benzene (0.7-1.7 ppbv), and toluene (13-20 ppbv). At some of the sampling locations, odorous compounds such as carbon disulfide and dimethyl sulfide levels exceed threshold values. The estimated toluene/benzene ratio is very high at most of the sites. However, the total amount of VOC is reduced over the years from 2000 to 2003 due to strict implementation on use and discharge of solvents in industries. There exists no definite seasonal pattern for sporadic occurrence of high levels of some of the volatile organics. Stagnant weather conditions with low wind speeds aid accumulation of toxic species at ground level. The results entail that hi-tech semiconductor industries are still a potential source for harmful organic substances to surrounding microenvironment.

It’s all about volatility of volatility

DEFF Research Database (Denmark)

Grassi, Stefano; Santucci de Magistris, Paolo

2015-01-01

The persistent nature of equity volatility is investigated by means of a multi-factor stochastic volatility model with time varying parameters. The parameters are estimated by means of a sequential matching procedure which adopts as auxiliary model a time-varying generalization of the HAR model f...

Characterization of volatiles in Beaten cheeses (bieno sirenje by SPME/GC-MC: Influence of geographical origin

Directory of Open Access Journals (Sweden)

Sulejmani Erhan

2014-01-01

Full Text Available In this study, the volatile profiles of a type of economically important cheeses for the FYR Macedonian dairy sector were characterized. A total of eighteen samples belonged to 6 different geographical regions of Beaten cheese, including cheeses from Kumanovo, Tetovo, Struga, Resen, Veles and Radovish were comparatively studied for their volatile profiles. Sixty two volatile compounds were identified in the cheeses by solid-phase microextraction combined with gas chromatography-mass spectrometry and the results are discussed based on their chemical classes (18 esters, 13 ketones, 10 acids, 8 alcohols, 5 terpenes, and 8 miscellaneous compounds. Acids, esters and alcohols were the most abundant classes identified and were highly dependent on the geographical origin of cheeses. Beaten cheese from Struga had the highest levels of carboxylic acids, ketones, alcohols, esters and terpenes. The Beaten cheese from other geographical origin had low levels of volatiles probably from the effect of variable characteristics of used milk and different cheese making process which affects the biochemical processes. The results suggest that each cheese from different geographical regions had different volatiles profile and the manufacturing technique as well as the ripening stage of the cheeses played a major role on the volatile compounds’ distribution.

Nest Predation Deviates from Nest Predator Abundance in an Ecologically Trapped Bird.

Science.gov (United States)

Hollander, Franck A; Van Dyck, Hans; San Martin, Gilles; Titeux, Nicolas

2015-01-01

In human-modified environments, ecological traps may result from a preference for low-quality habitat where survival or reproductive success is lower than in high-quality habitat. It has often been shown that low reproductive success for birds in preferred habitat types was due to higher nest predator abundance. However, between-habitat differences in nest predation may only weakly correlate with differences in nest predator abundance. An ecological trap is at work in a farmland bird (Lanius collurio) that recently expanded its breeding habitat into open areas in plantation forests. This passerine bird shows a strong preference for forest habitat, but it has a higher nest success in farmland. We tested whether higher abundance of nest predators in the preferred habitat or, alternatively, a decoupling of nest predator abundance and nest predation explained this observed pattern of maladaptive habitat selection. More than 90% of brood failures were attributed to nest predation. Nest predator abundance was more than 50% higher in farmland, but nest predation was 17% higher in forest. Differences between nest predation on actual shrike nests and on artificial nests suggested that parent shrikes may facilitate nest disclosure for predators in forest more than they do in farmland. The level of caution by parent shrikes when visiting their nest during a simulated nest predator intrusion was the same in the two habitats, but nest concealment was considerably lower in forest, which contributes to explaining the higher nest predation in this habitat. We conclude that a decoupling of nest predator abundance and nest predation may create ecological traps in human-modified environments.

Latent Integrated Stochastic Volatility, Realized Volatility, and Implied Volatility: A State Space Approach

DEFF Research Database (Denmark)

Bach, Christian; Christensen, Bent Jesper

process is downward biased. Implied volatility performs better than any of the alternative realized measures when forecasting future integrated volatility. The results are largely similar across the stock market (S&P 500), bond market (30-year U.S. T-bond), and foreign currency exchange market ($/£ )....

DOES ENERGY CONSUMPTION VOLATILITY AFFECT REAL GDP VOLATILITY? AN EMPIRICAL ANALYSIS FOR THE UK

Directory of Open Access Journals (Sweden)

Abdul Rashid

2013-10-01

Full Text Available This paper empirically examines the relation between energy consumption volatility and unpredictable variations in real gross domestic product (GDP in the UK. Estimating the Markov switching ARCH model we find a significant regime switching in the behavior of both energy consumption and GDP volatility. The results from the Markov regime-switching model show that the variability of energy consumption has a significant role to play in determining the behavior of GDP volatilities. Moreover, the results suggest that the impacts of unpredictable variations in energy consumption on GDP volatility are asymmetric, depending on the intensity of volatility. In particular, we find that while there is no significant contemporaneous relationship between energy consumption volatility and GDP volatility in the first (low-volatility regime, GDP volatility is significantly positively related to the volatility of energy utilization in the second (high-volatility regime.

Leaf Volatile Compounds and Associated Gene Expression during Short-Term Nitrogen Deficient Treatments in Cucumis Seedlings

Directory of Open Access Journals (Sweden)

Jie Deng

2016-11-01

Full Text Available Nitrogen (N is an important macronutrient for plant growth and development, but the regulatory mechanism of volatile compounds in response to N deficiency is not well understood, especially in cucumber, which consumes excessive N during growth. In this study, the major volatile compounds from cucumber leaves subjected to N deficiency were analyzed by GC-MS. A total of 24 volatile components were identified including 15 aldehydes, two ketones, two alkenes, and five other volatile compounds in 9930 leaves. Principal component analysis using volatile compounds from cucumber leaves provided good separation between N-sufficient and N-deficient treatments. The main volatiles in cucumber leaves were found to be C6 and C9 aldehydes, especially (E-2-hexanal and (E,Z-2,6-nonadienal. (E-2-hexanal belonged to the C6 aldehyde and was the most abundant compound, whereas (E,Z-2,6-nonadienal was the chief component of C9 aldehydes. During N-deficient treatment, short-chain volatile content was significantly improved at 5 day, other volatiles displayed significant reduction or no significantly changes in all sampling points. Improvement of short-chain volatiles was confirmed in the six other inbred lines at 5 day after N-deficient treatments. The expression analysis of 12 cucumber LOX genes and two HPL genes revealed that CsLOX19, CsLOX20, and CsLOX22 had common up-regulated expression patterns in response to N-deficient stress in most inbred lines; meanwhile, most sample points of CsHPL1 also had significant up-regulated expression patterns. This research focused on the relationship between volatiles in cucumber and different nitrogen environments to provide valuable insight into the effect of cultivation and management of the quality of cucumber and contributes to further research on volatile metabolism in cucumber.

Realized Volatility Risk

NARCIS (Netherlands)

D.E. Allen (David); M.J. McAleer (Michael); M. Scharth (Marcel)

2013-01-01

textabstractIn this paper we document that realized variation measures constructed from highfrequency returns reveal a large degree of volatility risk in stock and index returns, where we characterize volatility risk by the extent to which forecasting errors in realized volatility are substantive.

Characterization of volatile aroma compounds in different brewing barley cultivars.

Science.gov (United States)

Dong, Liang; Hou, Yingmin; Li, Feng; Piao, Yongzhe; Zhang, Xiao; Zhang, Xiaoyu; Li, Cheng; Zhao, Changxin

2015-03-30

Beer is a popular alcoholic malt beverage resulting from fermentation of the aqueous extract of malted barley with hops. The aroma of brewing barley impacts the flavor of beer indirectly, because some flavor compounds or their precursors in beer come from the barley. The objectives of this research were to study volatile profiles and to characterize odor-active compounds of brewing barley in order to determine the variability of the aroma composition among different brewing barley cultivars. Forty-one volatiles comprising aldehydes, ketones, alcohols, organic acids, aromatic compounds and furans were identified using solid phase microextraction combined with gas chromatography/mass spectrometry, among which aldehydes, alcohols and ketones were quantitatively in greatest abundance. Quantitative measurements performed by means of solvent extraction and calculation of odor activity values revealed that acetaldehyde, 2-methylpropanal, 3-methylbutanal, 2-methylbutanal, hexanal, heptanal, octanal, nonanal, 3-methyl-1-butanol, cyclopentanol, 2,3-butanedione, 2,3-pentanedione, 2-heptanone, acetic acid, ethyl acetate, 2-pentylfuran and benzeneacetaldehyde, whose concentrations exceeded their odor thresholds, could be considered as odor-active compounds of brewing barley. Principal component analysis was employed to evaluate the differences among cultivars. The results demonstrated that the volatile profile based on the concentrations of aroma compounds enabled good differentiation of most barley cultivars. © 2014 Society of Chemical Industry.

FORMING CHONDRULES IN IMPACT SPLASHES. II. VOLATILE RETENTION

Energy Technology Data Exchange (ETDEWEB)

Dullemond, Cornelis Petrus; Harsono, Daniel; Stammler, Sebastian Markus [Institute for Theoretical Astrophysics, Heidelberg University, Albert-Ueberle-Strasse 2, D-69120 Heidelberg (Germany); Johansen, Anders [Lund Observatory, Department of Astronomy and Theoretical Physics, Lund University, Box 43, SE-22100 Lund (Sweden)

2016-11-20

Solving the mystery of the origin of chondrules is one of the most elusive goals in the field of meteoritics. Recently, the idea of planet(esimal) collisions releasing splashes of lava droplets, long considered out of favor, has been reconsidered as a possible origin of chondrules by several papers. One of the main problems with this idea is the lack of quantitative and simple models that can be used to test this scenario by directly comparing to the many known observables of chondrules. In Paper I of this series, we presented a simple thermal evolution model of a spherically symmetric expanding cloud of molten lava droplets that is assumed to emerge from a collision between two planetesimals. The production of lava could be either because the two planetesimals were already in a largely molten (or almost molten) state due to heating by {sup 26}Al, or due to impact jetting at higher impact velocities. In the present paper, number II of this series, we use this model to calculate whether or not volatile elements such as Na and K will remain abundant in these droplets or whether they will get depleted due to evaporation. The high density of the droplet cloud (e.g., small distance between adjacent droplets) causes the vapor to quickly reach saturation pressure and thus shuts down further evaporation. We show to what extent, and under which conditions, this keeps the abundances of these elements high, as is seen in chondrules. We find that for most parameters of our model (cloud mass, expansion velocity, initial temperature) the volatile elements Mg, Si, and Fe remain entirely in the chondrules. The Na and K abundances inside the droplets will initially stay mostly at their initial values due to the saturation of the vapor pressure, but at some point start to drop due to the cloud expansion. However, as soon as the temperature starts to decrease, most or all of the vapor recondenses again. At the end, the Na and K elements retain most of their initial abundances, albeit

Virtual volatility

Science.gov (United States)

Silva, A. Christian; Prange, Richard E.

2007-03-01

We introduce the concept of virtual volatility. This simple but new measure shows how to quantify the uncertainty in the forecast of the drift component of a random walk. The virtual volatility also is a useful tool in understanding the stochastic process for a given portfolio. In particular, and as an example, we were able to identify mean reversion effect in our portfolio. Finally, we briefly discuss the potential practical effect of the virtual volatility on an investor asset allocation strategy.

Nest Predation Deviates from Nest Predator Abundance in an Ecologically Trapped Bird.

Directory of Open Access Journals (Sweden)

Franck A Hollander

Full Text Available In human-modified environments, ecological traps may result from a preference for low-quality habitat where survival or reproductive success is lower than in high-quality habitat. It has often been shown that low reproductive success for birds in preferred habitat types was due to higher nest predator abundance. However, between-habitat differences in nest predation may only weakly correlate with differences in nest predator abundance. An ecological trap is at work in a farmland bird (Lanius collurio that recently expanded its breeding habitat into open areas in plantation forests. This passerine bird shows a strong preference for forest habitat, but it has a higher nest success in farmland. We tested whether higher abundance of nest predators in the preferred habitat or, alternatively, a decoupling of nest predator abundance and nest predation explained this observed pattern of maladaptive habitat selection. More than 90% of brood failures were attributed to nest predation. Nest predator abundance was more than 50% higher in farmland, but nest predation was 17% higher in forest. Differences between nest predation on actual shrike nests and on artificial nests suggested that parent shrikes may facilitate nest disclosure for predators in forest more than they do in farmland. The level of caution by parent shrikes when visiting their nest during a simulated nest predator intrusion was the same in the two habitats, but nest concealment was considerably lower in forest, which contributes to explaining the higher nest predation in this habitat. We conclude that a decoupling of nest predator abundance and nest predation may create ecological traps in human-modified environments.

Characterization and semiquantitative analysis of volatiles in seedless watermelon varieties using solid-phase microextraction.

Science.gov (United States)

Beaulieu, John C; Lea, Jeanne M

2006-10-04

Seedless triploid watermelons have increased in popularity since the early 1990s, and the demand for seedless fruit is on the rise. Sweetness and sugars are crucial breeding focuses for fruit quality. Volatiles also play an important role; yet, we found no literature for seedless varieties and no reports using solid-phase microextraction (SPME) in watermelon. The objective of this experiment was to identify volatile and semivolatile compounds in five seedless watermelon varieties using carboxen divinylbenzene polydimethylsiloxane solid-phase microextraction (SPME) with gas chromatography-mass spectrometry (GC-MS). Fully ripe watermelon was squeezed through miracloth to produce rapid juice extracts for immediate headspace SPME GC-MS. Aldehydes, alcohols, ketones, and one furan (2-pentyl furan, a lipid oxidation product) were recovered. On the basis of total ion count peak area, the most abundant compounds in five varieties were 3-nonen-1-ol/(E,Z)-2,6-nonadienal (16.5-28.2%), (E)-2-nonenal (10.6-22.5%), and (Z)-6-nonenal (2.0-11.3%). Hexanal was most abundant (37.7%) in one variety (Petite Perfection) [corrected] The most abundant ketone was 6-methyl-5-hepten-2-one (2.7-7.7%). Some sensory attributes reported for these compounds are melon, citrus, cucumber, orange, rose, floral, guava, violet, vegetable, green, grassy, herbaceous, pungent, fatty, sweet, and waxy. Identifying and relating these compounds to sensory attributes will allow for future monitoring of the critical flavor compounds in seedless watermelon after processing and throughout fresh-cut storage.

Chemical Composition of the Volatile Components of Tropaeolum majus L. (Garden Nasturtium from North Western Algeria

Directory of Open Access Journals (Sweden)

B. BENYELLES

2015-11-01

Full Text Available Essential oil from Tropaeolum majus L. aerial parts, a plant native to North Western Algeria, was obtained by hydrodistillation. The oil volatile components were identified by a combination of gas chromatography/flame ionization detection (GC/FID, GC-mass spectrometry (GC-MS techniques, and NMR spectroscopy. Nine components representing 92.0 % of the essential oil total (GC/FID chromatogram were identified. The most abundant compounds were benzyl isothiocyanate (82.5 %, benzene acetonitrile (3.9 % and 2-phenylethyl isovalerate (2.9 %. Higher content in nitrogen- and sulfur-containing compounds accounting to 86.4 % of the volatile fraction composition of T. majus were quantified.

Uropygial gland volatiles may code for olfactory information about sex, individual, and species in Bengalese finches Lonchura striata

Directory of Open Access Journals (Sweden)

Jian-Xu ZHANG et al.

2009-10-01

Full Text Available Over-shadowed by eye-catching vocal and visual signals, chemical communication has long been overlooked in birds. This study aimed at exploring whether volatile composition of the uropygial gland secretion (UGS of birds was associated with the information about sex, individual and species. By using dichloromethane extraction and gas chromatography-mass spectrometry (GC-MS, we analyzed the UGS volatiles of domesticated Bengalese finches (Lonchura striata, Estrildiea which is also known as white-rumped munias. We characterized 16 volatile molecules from the UGS, including eight n-alkanols, five diesters, an ester, an aldehyde and a fatty acid, and quantified them in terms of GC peak area percentages (relative abundances. Among these compounds, hexadecanol and octadecanol were major components in both sexes. The former was richer in males than females and the latter richer in females than males, suggesting that they might be male and female pheromone candidates, respectively. The high inter-individual variations, in relative abundance, of the UGS volatiles implied that they might carry information about individuality. The similarity between GC profiles of the UGS and wing feather from same individuals indicates that the birds might preen the secretion to their feathers to transmit chemical cues. Additionally, by comparing with three sympatric passerine species,i.e., zebra finches Taeniopygia guttata, yellow-bowed buntings Emberiza chrysophrys and rooks Corvus frugilegus, we found that the composition of C13-C18 alkanols in the UGS might contain information about species. Our study also show that quantitative differences (degree of same UGS volatiles might be the key for the Bengalese finch to code for information about sex and individuality whereas both the kind and degree of UGS constituents could be utilized to code for information about species [Current Zoology 55 (5:–2009].

THE CURIOUS CASE OF ELEMENTAL ABUNDANCE DIFFERENCES IN THE DUAL HOT JUPITER HOSTS WASP-94A AND B

Energy Technology Data Exchange (ETDEWEB)

Teske, Johanna K. [Carnegie Department of Terrestrial Magnetism, 5241 Broad Branch Road, NW, Washington, DC 20015 (United States); Khanal, Sandhya; Ramírez, Ivan, E-mail: jteske@carnegiescience.edu [McDonald Observatory and Department of Astronomy, University of Texas at Austin, 2515 Speedway, Stop C1402, Austin, TX 78712-1205 (United States)

2016-03-01

Binary stars provide an ideal laboratory for investigating the potential effects of planet formation on stellar composition. Assuming that the stars formed in the same environment/from the same material, any compositional anomalies between binary components might indicate differences in how material was sequestered in planets, or accreted by the star in the process of planet formation. We present here a study of the elemental abundance differences between WASP-94A and B, a pair of stars that each host a hot Jupiter exoplanet. The two stars are very similar in spectral type (F8 and F9), and their ∼2700 au separation suggests that their protoplanetary disks were likely not influenced by stellar interactions, but WASP-94Ab’s orbit—misaligned with the host star spin axis and likely retrograde—points toward a dynamically active formation mechanism, perhaps different from that of WASP-94Bb, which is not misaligned and has a nearly circular orbit. Based on our high-quality spectra and strictly relative abundance analysis, we detect a depletion of volatiles (∼−0.02 dex, on average) and enhancement of refractories (∼0.01 dex) in WASP-94A relative to B (standard errors are ∼0.005 dex). This is different from every other published case of binary host star abundances, in which either no significant abundance differences are reported or there is some degree of enhancement in all elements, including volatiles. Several scenarios that may explain the abundance trend are discussed, but none can be definitively accepted or rejected. Additional high-contrast imaging observations to search for companions that may be dynamically affecting the system, as well as a larger sample of binary host star studies, are needed to better understand the curious abundance trends we observe in WASP-94A and B.

Realized volatility and absolute return volatility: a comparison indicating market risk.

Science.gov (United States)

Zheng, Zeyu; Qiao, Zhi; Takaishi, Tetsuya; Stanley, H Eugene; Li, Baowen

2014-01-01

Measuring volatility in financial markets is a primary challenge in the theory and practice of risk management and is essential when developing investment strategies. Although the vast literature on the topic describes many different models, two nonparametric measurements have emerged and received wide use over the past decade: realized volatility and absolute return volatility. The former is strongly favored in the financial sector and the latter by econophysicists. We examine the memory and clustering features of these two methods and find that both enable strong predictions. We compare the two in detail and find that although realized volatility has a better short-term effect that allows predictions of near-future market behavior, absolute return volatility is easier to calculate and, as a risk indicator, has approximately the same sensitivity as realized volatility. Our detailed empirical analysis yields valuable guidelines for both researchers and market participants because it provides a significantly clearer comparison of the strengths and weaknesses of the two methods.

Realized volatility and absolute return volatility: a comparison indicating market risk.

Directory of Open Access Journals (Sweden)

Zeyu Zheng

Full Text Available Measuring volatility in financial markets is a primary challenge in the theory and practice of risk management and is essential when developing investment strategies. Although the vast literature on the topic describes many different models, two nonparametric measurements have emerged and received wide use over the past decade: realized volatility and absolute return volatility. The former is strongly favored in the financial sector and the latter by econophysicists. We examine the memory and clustering features of these two methods and find that both enable strong predictions. We compare the two in detail and find that although realized volatility has a better short-term effect that allows predictions of near-future market behavior, absolute return volatility is easier to calculate and, as a risk indicator, has approximately the same sensitivity as realized volatility. Our detailed empirical analysis yields valuable guidelines for both researchers and market participants because it provides a significantly clearer comparison of the strengths and weaknesses of the two methods.

Unstable volatility

DEFF Research Database (Denmark)

Casas, Isabel; Gijbels, Irène

2012-01-01

The objective of this paper is to introduce the break-preserving local linear (BPLL) estimator for the estimation of unstable volatility functions for independent and asymptotically independent processes. Breaks in the structure of the conditional mean and/or the volatility functions are common...... in Finance. Nonparametric estimators are well suited for these events due to the flexibility of their functional form and their good asymptotic properties. However, the local polynomial kernel estimators are not consistent at points where the volatility function has a break. The estimator presented...

Volatility measurement of atmospheric submicron aerosols in an urban atmosphere in southern China

Science.gov (United States)

Cao, Li-Ming; Huang, Xiao-Feng; Li, Yuan-Yuan; Hu, Min; He, Ling-Yan

2018-02-01

Aerosol pollution has been a very serious environmental problem in China for many years. The volatility of aerosols can affect the distribution of compounds in the gas and aerosol phases, the atmospheric fates of the corresponding components, and the measurement of the concentration of aerosols. Compared to the characterization of chemical composition, few studies have focused on the volatility of aerosols in China. In this study, a thermodenuder aerosol mass spectrometer (TD-AMS) system was deployed to study the volatility of non-refractory submicron particulate matter (PM1) species during winter in Shenzhen. To our knowledge, this paper is the first report of the volatilities of aerosol chemical components based on a TD-AMS system in China. The average PM1 mass concentration during the experiment was 42.7±20.1 µg m-3, with organic aerosol (OA) being the most abundant component (43.2 % of the total mass). The volatility of chemical species measured by the AMS varied, with nitrate showing the highest volatility, with a mass fraction remaining (MFR) of 0.57 at 50 °C. Organics showed semi-volatile characteristics (the MFR was 0.88 at 50 °C), and the volatility had a relatively linear correlation with the TD temperature (from the ambient temperature to 200 °C), with an evaporation rate of 0.45 % °C-1. Five subtypes of OA were resolved from total OA using positive matrix factorization (PMF) for data obtained under both ambient temperature and high temperatures through the TD, including a hydrocarbon-like OA (HOA, accounting for 13.5 %), a cooking OA (COA, 20.6 %), a biomass-burning OA (BBOA, 8.9 %), and two oxygenated OAs (OOAs): a less-oxidized OOA (LO-OOA, 39.1 %) and a more-oxidized OOA (MO-OOA, 17.9 %). Different OA factors presented different volatilities, and the volatility sequence of the OA factors at 50 °C was HOA (MFR of 0.56) > LO-OOA (0.70) > COA (0.85) ≈ BBOA (0.87) > MO-OOA (0.99), which was not completely consistent with the sequence of their O

Pluto's Volatile Transport

Science.gov (United States)

Young, Leslie

2012-10-01

Pluto's varying subsolar latitude and heliocentric distance leads to large variations in the surface volatile distribution and surface pressure. I present results of new volatile transport models (Young 2012a, b). The models include insolation, thermal emission, subsurface conduction, heating of a volatile slab, internal heat flux, latent heat of sublimation, and strict global mass balance. Numeric advances include initial conditions that allow for rapid convergence, efficient computation with matrix arithmetic, and stable Crank-Nicholson timesteps for both bare and volatile-covered areas. Runs of the model show six distinct seasons on Pluto. (1) As Pluto approaches perihelion, the volatiles on the old winter pole (the Rotational North Pole, RNP) becomes more directly illuminated , and the pressure and albedo rise rapidly. (2) When a new ice cap forms on the Rotational South Pole, RSP, volatiles are exchanged between poles. The pressure and albedo change more slowly. (3) When all volatiles have sublimed from the RNP, the albedo and pressure drop rapidly. (4-6) A similar pattern is repeated near aphelion with a reversal of the roles and the poles. I will compare results with earlier Pluto models of Hansen and Paige (1996), show the dependence on parameters such as substrate inertia, and make predictions for the New Horizons flyby of Pluto in 2015. This work was supported, in part, by funding from NASA Planetary Atmospheres Grant NNG06GF32G and the Spitzer project (JPL research support Agreement 1368573). Hansen, C. J. and D. A. Paige 1996. Seasonal Nitrogen Cycles on Pluto. Icarus 120, 247-265. Young, L. A. 2012a. Volatile transport on inhomogeneous surfaces: I - Analytic expressions, with application to Pluto’s day. Icarus, in press Young, L. A. 2012b. Volatile transport on inhomogeneous surfaces: II. Numerical calculations, with application to Pluto's season. In preparation.

Effect of Trichoderma viride biofertilizer on ammonia volatilization from an alkaline soil in Northern China.

Science.gov (United States)

Wang, Xia; Xu, Shengjun; Wu, Shanghua; Feng, Shugeng; Bai, Zhihui; Zhuang, Guoqiang; Zhuang, Xuliang

2018-04-01

Ammonia (NH 3 ) volatilization is one of the primary pathways of nitrogen (N) loss from soils after chemical fertilizer is applied, especially from the alkaline soils in Northern China, which results in lower efficiency for chemical fertilizers. Therefore, we conducted an incubation experiment using an alkaline soil from Tianjin (pH8.37-8.43) to evaluate the suppression effect of Trichoderma viride (T. viride) biofertilizer on NH 3 volatilization, and compared the differences in microbial community structure among all samples. The results showed that viable T. viride biofertilizer (T) decreased NH 3 volatilization by 42.21% compared with conventional fertilizer ((CK), urea), while nonviable T. viride biofertilizer (TS) decreased NH 3 volatilization by 32.42%. NH 3 volatilization was significantly higher in CK and sweet potato starch wastewater (SPSW) treatments during the peak period. T. viride biofertilizer also improved the transfer of ammonium from soil to sweet sorghum. Plant dry weights increased 91.23% and 61.08% for T and TS, respectively, compared to CK. Moreover, T. viride biofertilizer enhanced nitrification by increasing the abundance of ammonium-oxidizing archaea (AOA) and ammonium-oxidizing bacteria (AOB). The results of high-throughput sequencing indicated that the microbial community structure and composition were significantly changed by the application of T. viride biofertilizer. This study demonstrated the immense potential of T. viride biofertilizer in reducing NH 3 volatilization from alkaline soil and simultaneously improving the utilization of fertilizer N by sweet sorghum. Copyright © 2017. Published by Elsevier B.V.

Constraining the volatile fraction of planets from transit observations

Science.gov (United States)

Alibert, Y.

2016-06-01

Context. The determination of the abundance of volatiles in extrasolar planets is very important as it can provide constraints on transport in protoplanetary disks and on the formation location of planets. However, constraining the internal structure of low-mass planets from transit measurements is known to be a degenerate problem. Aims: Using planetary structure and evolution models, we show how observations of transiting planets can be used to constrain their internal composition, in particular the amount of volatiles in the planetary interior, and consequently the amount of gas (defined in this paper to be only H and He) that the planet harbors. We first explore planets that are located close enough to their star to have lost their gas envelope. We then concentrate on planets at larger distances and show that the observation of transiting planets at different evolutionary ages can provide statistical information on their internal composition, in particular on their volatile fraction. Methods: We computed the evolution of low-mass planets (super-Earths to Neptune-like) for different fractions of volatiles and gas. We used a four-layer model (core, silicate mantle, icy mantle, and gas envelope) and computed the internal structure of planets for different luminosities. With this internal structure model, we computed the internal and gravitational energy of planets, which was then used to derive the time evolution of the planet. Since the total energy of a planet depends on its heat capacity and density distribution and therefore on its composition, planets with different ice fractions have different evolution tracks. Results: We show for low-mass gas-poor planets that are located close to their central star that assuming evaporation has efficiently removed the entire gas envelope, it is possible to constrain the volatile fraction of close-in transiting planets. We illustrate this method on the example of 55 Cnc e and show that under the assumption of the absence of

Using Schumann Resonance Measurements for Constraining the Water Abundance on the Giant Planets - Implications for the Solar System Formation

Science.gov (United States)

Simoes, Fernando; Pfaff, Robert; Hamelin, Michel; Klenzing, Jeffrey; Freudenreich, Henry; Beghin, Christian; Berthelier, Jean-Jacques; Bromund, Kenneth; Grard, Rejean; Lebreton, Jean-Pierre;

USING SCHUMANN RESONANCE MEASUREMENTS FOR CONSTRAINING THE WATER ABUNDANCE ON THE GIANT PLANETS—IMPLICATIONS FOR THE SOLAR SYSTEM'S FORMATION

International Nuclear Information System (INIS)

Simões, Fernando; Pfaff, Robert; Klenzing, Jeffrey; Freudenreich, Henry; Bromund, Kenneth; Martin, Steven; Rowland, Douglas; Hamelin, Michel; Berthelier, Jean-Jacques; Béghin, Christian; Lebreton, Jean-Pierre; Grard, Rejean; Sentman, Davis; Takahashi, Yukihiro; Yair, Yoav

2012-01-01

The formation and evolution of the solar system is closely related to the abundance of volatiles, namely water, ammonia, and methane in the protoplanetary disk. Accurate measurement of volatiles in the solar system is therefore important for understanding not only the nebular hypothesis and origin of life but also planetary cosmogony as a whole. In this work, we propose a new remote sensing technique to infer the outer planets' water content by measuring Tremendously and Extremely Low Frequency (TLF-ELF) electromagnetic wave characteristics (Schumann resonances) excited by lightning in their gaseous envelopes. Schumann resonance detection can be potentially used for constraining the uncertainty of volatiles of the giant planets, mainly Uranus and Neptune, because such TLF-ELF wave signatures are closely related to the electric conductivity profile and water content.

Measurement of volatile plant compounds in field ambient air by thermal desorption-gas chromatography-mass spectrometry.

Science.gov (United States)

Cai, Xiao-Ming; Xu, Xiu-Xiu; Bian, Lei; Luo, Zong-Xiu; Chen, Zong-Mao

2015-12-01

Determination of volatile plant compounds in field ambient air is important to understand chemical communication between plants and insects and will aid the development of semiochemicals from plants for pest control. In this study, a thermal desorption-gas chromatography-mass spectrometry (TD-GC-MS) method was developed to measure ultra-trace levels of volatile plant compounds in field ambient air. The desorption parameters of TD, including sorbent tube material, tube desorption temperature, desorption time, and cold trap temperature, were selected and optimized. In GC-MS analysis, the selected ion monitoring mode was used for enhanced sensitivity and selectivity. This method was sufficiently sensitive to detect part-per-trillion levels of volatile plant compounds in field ambient air. Laboratory and field evaluation revealed that the method presented high precision and accuracy. Field studies indicated that the background odor of tea plantations contained some common volatile plant compounds, such as (Z)-3-hexenol, methyl salicylate, and (E)-ocimene, at concentrations ranging from 1 to 3400 ng m(-3). In addition, the background odor in summer was more abundant in quality and quantity than in autumn. Relative to previous methods, the TD-GC-MS method is more sensitive, permitting accurate qualitative and quantitative measurements of volatile plant compounds in field ambient air.

Influence of modified atmosphere packaging on volatile compounds and physicochemical and antioxidant attributes of fresh-cut pineapple (Ananas comosus).

Science.gov (United States)

Montero-Calderón, Marta; Rojas-Graü, María Alejandra; Aguiló-Aguayo, Ingrid; Soliva-Fortuny, Robert; Martín-Belloso, Olga

2010-04-28

The effects of modified atmosphere packaging on volatile compound content and physicochemical and antioxidant attributes of Gold cultivar fresh-cut pineapples were assessed throughout storage at 5 degrees C. Fresh-cut pineapple pieces were packed under LO (low oxygen, 12% O(2), 1% CO(2)), AIR (20.9% O(2)) and HO (high oxygen, 38% O(2)) headspace atmospheres. Methyl butanoate, methyl 2-methylbutanoate, and methyl hexanoate were the most abundant volatiles regardless of the packaging atmosphere and days of storage; whereas most odor active volatiles were methyl and ethyl 2-methylbutanoate, 2,5-dimethyl-4-methoxy-3(2H)-furanone and ethyl hexanoate. Physicochemical attributes of pineapple did not significantly vary, whereas vitamin C content and total antioxidant capacity were lower for fresh-cut pineapple in HO (488 +/- 38 mg/100 mg(fw) and 54.4 +/- 5.7%, respectively) than for LO and AIR packages. Storage life of fresh-cut pineapple was limited to 14 days by volatile compounds losses and fermentation processes.

Normalization for Implied Volatility

OpenAIRE

Fukasawa, Masaaki

2010-01-01

We study specific nonlinear transformations of the Black-Scholes implied volatility to show remarkable properties of the volatility surface. Model-free bounds on the implied volatility skew are given. Pricing formulas for the European options which are written in terms of the implied volatility are given. In particular, we prove elegant formulas for the fair strikes of the variance swap and the gamma swap.

Money growth volatility and the demand for money in Germany: Friedman's volatility hypothesis revisited

OpenAIRE

Brüggemann, Imke; Nautz, Dieter

1997-01-01

Recently, the Bundesbank claimed that monetary targeting has become considerably more diffcult by the increased volatility of short-term money growth. The present paper investigates the impact of German money growth volatility on income velocity and money demand in view of Friedman's money growth volatility hypothesis. Granger-causality tests provide some evidence for a velocity-volatility linkage. However the estimation of volatility-augmented money demand functions reveals that - in contras...

Monitoring of Yeast Communities and Volatile Flavor Changes During Traditional Korean Soy Sauce Fermentation.

Science.gov (United States)

Song, Young-Ran; Jeong, Do-Youn; Baik, Sang-Ho

2015-09-01

Flavor development in soy sauce is significantly related to the diversity of yeast species. Due to its unique fermentation with meju, the process of making Korean soy sauce gives rise to a specific yeast community and, therefore, flavor profile; however, no detailed analysis of the identifying these structure has been performed. Changes in yeast community structure during Korean soy sauce fermentation were examined using both culture-dependent and culture-independent methods with simultaneous analysis of the changes in volatile compounds by GC-MS analysis. During fermentation, Candida, Pichia, and Rhodotorula sp. were the dominant species, whereas Debaryomyces, Torulaspora, and Zygosaccharomyces sp. were detected only at the early stage. In addition, Cryptococcus, Microbotryum, Tetrapisispora, and Wickerhamomyces were detected as minor strains. Among the 62 compounds identified in this study, alcohols, ketones, and pyrazines were present as the major groups during the initial stages, whereas the abundance of acids with aldehydes increased as the fermentation progressed. Finally, the impacts of 10 different yeast strains found to participate in fermentation on the formation of volatile compounds were evaluated under soy-based conditions. It was revealed that specific species produced different profiles of volatile compounds, some of which were significant flavor contributors, especially volatile alcohols, aldehydes, esters, and ketones. © 2015 Institute of Food Technologists®

Chasing volatility

DEFF Research Database (Denmark)

Caporin, Massimiliano; Rossi, Eduardo; Santucci de Magistris, Paolo

The realized volatility of financial returns is characterized by persistence and occurrence of unpreditable large increments. To capture those features, we introduce the Multiplicative Error Model with jumps (MEM-J). When a jump component is included in the multiplicative specification, the condi......The realized volatility of financial returns is characterized by persistence and occurrence of unpreditable large increments. To capture those features, we introduce the Multiplicative Error Model with jumps (MEM-J). When a jump component is included in the multiplicative specification...... estimate alternative specifications of the model using a set of daily bipower measures for 7 stock indexes and 16 individual NYSE stocks. The estimates of the jump component confirm that the probability of jumps dramatically increases during the financial crisis. Compared to other realized volatility...... models, the introduction of the jump component provides a sensible improvement in the fit, as well as for in-sample and out-of-sample volatility tail forecasts....

Inhibitory effect of betel quid on the volatility of methyl mercaptan.

Science.gov (United States)

Wang, C K; Chen, S L; Wu, M G

2001-04-01

Betel quid, a popular natural masticatory in Taiwan, is mainly composed of fresh areca fruit, Piper betle (leaf or inflorescence), and slaked lime paste. People say that halitosis disappears during betel quid chewing. In this study, the removal of mouth odor during betel quid chewing was discussed by using a model system which measured its inhibition on the volatility of methyl mercaptan. Results showed that crude extracts of betel quid (the mixture of areca fruit, Piper betle, and slaked lime paste) and extracts of the mixture of areca fruit and slaked lime paste exhibited marked effects on the volatility of methyl mercaptan, and the inhibition function increased when increasing amounts of slaked lime paste were added. The same condition (increased inhibition) was also found by replacing the slaked lime paste with alkaline salts (calcium hydroxide, potassium hydroxide, or sodium hydroxide). Areca fruit, the major ingredient of betel quid, contained abundant phenolics. However, the crude phenolic extract of areca fruit did not show any inhibitory activity on the volatility of methyl mercaptan. Great inhibitory activity occurred only when the crude phenolic extract of areca fruit was treated with alkali. Further studies by using gel filtration determined that the effect probably came from the oxidative polymerization of phenolics of areca fruit after alkaline treatment.

Submillimetric Spectroscopic Observations of Volatiles in Comet C-2004 Q2 (Machholz)

Science.gov (United States)

DeVal-Borro, M.; Hartogh, P.; Jarchow, C.; Rengel, M.; Villanueva, G. L.; Kueppers, M.; Biver, N.; Bockelee-Morvan, D.; Crovisier, J.

2012-01-01

Submillimeter spectroscopic observations of comets provide an important tool for understanding their chemical composition and enable a taxonomic classification. Aims. We aim to determine the production rates of several parent- and product volatiles and the C-12/C-13 isotopic carbon ratio in the long-period comet C/2004 Q2 (Machholz), which is likely to originate from the Oort Cloud. Methods. The line emission from several molecules in the coma was measured with high signal-to-noise ratio in January 2005 at heliocentric distance of 1.2 AU by means of high-resolution spectroscopic observations using the Submillimeter Telescope (SMT) at the Arizona Radio Observatory (ARO). Results. We have obtained production rates of several volatiles (CH3OH, HCN, H(sup 13)CN, HNC, H2CO, CO, and CS) by comparing the observed and simulated line-integrated intensities. We calculated the synthetic profiles using a radiative transfer code that includes collisions between neutrals and electrons, and the effects of radiative pumping of the fundamental vibrational levels by solar infrared radiation. Furthermore, multiline observations of the CH3OH J = 7-6 series allow us to estimate the rotational temperature using the rotation diagram technique. We find that the CH3OH population distribution of the levels sampled by these lines can be described by a rotational temperature of 40 +/- 3 K. Derived mixing ratios relative to hydrogen cyanide are CO/CH3OH/H2CO/CS/HNC/HC-13N/HCN= 30.9/24.6/4.8/0.57/0.031/0.013/1 assuming a pointing offset of 8" due to the uncertain ephemeris at the time of the observations and the telescope pointing error. Conclusions. The measured relative molecular abundances in C/2004 Q2 (Machholz) are between low- to typical values of those obtained in Oort Cloud comets, suggesting that it has visited the inner solar system previously and undergone thermal processing. The HNC/HCN abundance ratio of approx 3.1% is comparable to that found in other comets, accounting for the

Oceanic Emissions and Atmospheric Depositions of Volatile Organic Compounds

Science.gov (United States)

Yang, M.; Blomquist, B.; Beale, R.; Nightingale, P. D.; Liss, P. S.

2015-12-01

Atmospheric volatile organic compounds (VOCs) affect the tropospheric oxidative capacity due to their ubiquitous abundance and relatively high reactivity towards the hydroxyal radical. Over the ocean and away from terrestrial emission sources, oxygenated volatile organic compounds (OVOCs) make up a large fraction of VOCs as airmasses age and become more oxidized. In addition to being produced or destroyed in the marine atmosphere, OVOCs can also be emitted from or deposited to the surface ocean. Here we first present direct air-sea flux measurements of three of the most abundant OVOCs - methanol, acetone, and acetaldehyde, by the eddy covariance technique from two cruises in the Atlantic: the Atlantic Meridional Transect in 2012 and the High Wind Gas Exchange Study in 2013. The OVOC mixing ratios were quantified by a high resolution proton-reaction-transfer mass spectrometer with isotopically labeled standards and their air-sea (net) fluxes were derived from the eddy covariance technique. Net methanol flux was consistently from the atmosphere to the surface ocean, while acetone varied from supersaturation (emission) in the subtropics to undersaturation (deposition) in the higher latitudes of the North Atlantic. The net air-sea flux of acetaldehyde is near zero through out the Atlantic despite the apparent supersaturation of this compound in the surface ocean. Knowing the dissolved concentrations and in situ production rates of these compounds in seawater, we then estimate their bulk atmospheric depositions and oceanic emissions. Lastly, we summarize the state of knowledge on the air-sea transport of a number of organic gasses, and postulate the magnitude and environmental impact of total organic carbon transfer between the ocean and the atmosphere.

Volatility in Equilibrium

DEFF Research Database (Denmark)

Bollerslev, Tim; Sizova, Natalia; Tauchen, George

Stock market volatility clusters in time, carries a risk premium, is fractionally inte- grated, and exhibits asymmetric leverage effects relative to returns. This paper develops a first internally consistent equilibrium based explanation for these longstanding empirical facts. The model is cast i......, and the dynamic cross-correlations of the volatility measures with the returns calculated from actual high-frequency intra-day data on the S&P 500 aggregate market and VIX volatility indexes....

American options under stochastic volatility

NARCIS (Netherlands)

Chockalingam, A.; Muthuraman, K.

2011-01-01

The problem of pricing an American option written on an underlying asset with constant price volatility has been studied extensively in literature. Real-world data, however, demonstrate that volatility is not constant, and stochastic volatility models are used to account for dynamic volatility

Proboscis extension reflex platform for volatiles and semi-volatiles detection

Energy Technology Data Exchange (ETDEWEB)

Wingo, Robert M. (Los Alamos, NM); McCabe, Kirsten J. (Los Alamos, NM); Haarmann, Timothy K. (Jemez Pueblo, NM)

2010-11-30

The present invention provides an apparatus for the detection of volatile and semi-volatile chemicals using the olfactory abilities of honey bees that are trained to respond to the presence of a specific chemical in a sample of gas with the proboscis extension reflex (PER). In particular, the geometry and arrangement of the parts of the apparatus are such that the amount of surface area in contact with the sample of gas prior to its introduction to the bees is minimized to improve the detection of particular volatile and semi-volatile that have a tendency to "stick" to contacting surfaces, especially certain chemicals associated with explosives and narcotics. According to another aspect of the present invention, a pre-concentrating means is incorporated with the device to effectively increase the concentration of "sticky" chemicals presented to the insects.

Volatile compounds of young wines from cabernet sauvignon, cabernet gernischet and chardonnay varieties grown in the loess plateau region of china.

Science.gov (United States)

Jiang, Bao; Zhang, Zhenwen

2010-12-10

In order to elucidate the aroma components of wine produced in the Loess Plateau region of China, volatile compounds of young wines from Cabernet Sauvignon, Cabernet Gernischet and Chardonnay varieties grown in the new ecological region were investigated for the first time in this research. Among the volatile compounds analyzed by HS-SPME with GC-MS, a total of 45, 44 and 42 volatile compounds were identified and quantified in Cabernet Sauvignon, Cabernet Gernischet and Chardonnay wines, respectively. In the volatiles detected, alcohols formed the most abundant group in the aroma compounds of the three wines, followed by esters and fatty acids. According to their odor active values (OAVs), 18 volatile compounds were always present in the three wines at concentrations higher than their threshold values, but ethyl octanoate, ethyl hexanoate, and isoamyl acetate were found to jointly contribute to 92.9%, 93.3%, and 98.7%, of the global aroma of Cabernet Sauvignon, Cabernet Gernischet and Chardonnay wines, respectively. These odorants are associated with "fruity'' and ''ripe fruit'' odor descriptors.

Volatile Compounds of Young Wines from Cabernet Sauvignon, Cabernet Gernischet and Chardonnay Varieties Grown in the Loess Plateau Region of China

Directory of Open Access Journals (Sweden)

Zhenwen Zhang

2010-12-01

Full Text Available In order to elucidate the aroma components of wine produced in the Loess Plateau region of China, volatile compounds of young wines from Cabernet Sauvignon, Cabernet Gernischet and Chardonnay varieties grown in the new ecological region were investigated for the first time in this research. Among the volatile compounds analyzed by HS-SPME with GC-MS, a total of 45, 44 and 42 volatile compounds were identified and quantified in Cabernet Sauvignon, Cabernet Gernischet and Chardonnay wines, respectively. In the volatiles detected, alcohols formed the most abundant group in the aroma compounds of the three wines, followed by esters and fatty acids. According to their odor active values (OAVs, 18 volatile compounds were always present in the three wines at concentrations higher than their threshold values, but ethyl octanoate, ethyl hexanoate, and isoamyl acetate were found to jointly contribute to 92.9%, 93.3%, and 98.7%, of the global aroma of Cabernet Sauvignon, Cabernet Gernischet and Chardonnay wines, respectively. These odorants are associated with “fruity’’ and ‘‘ripe fruit’’ odor descriptors.

Farmed and wild sea bass (Dicentrarchus labrax) volatile metabolites: a comparative study by SPME-GC/MS.

Science.gov (United States)

Vidal, Natalia P; Manzanos, María J; Goicoechea, Encarnación; Guillén, María D

2016-03-15

Farmed and wild European sea bass (Dicentrarchus labrax) could be distinguished by its volatile metabolites, an issue not addressed until now. The aim of this work was to study these metabolites by solid-phase microextraction followed by gas chromatography/mass spectrometry (SPME-GC/MS). Both farmed and wild sea bass have a great number of volatile metabolites, most of them being in low concentrations. These include alcohols, aldehydes, ketones, alkylfurans, acids, aliphatic and aromatic hydrocarbons, terpenes, sulfur and nitrogen derivatives, 2,6-di-tert-butyl-4-methylphenol and one derived compound, as well as 2,4,7,9-tetramethyl-5-decyne-4,7-diol, this latter compound presumably resulting from environmental contamination. Important differences have been detected between both types of sea bass, and also among individuals inside each group. Farmed specimens are richer in volatile metabolites than the wild counterparts; however, these latter, in general, contain a high number and abundance of metabolites resulting from microbial and enzymatic non-oxidative activity than the former. Clear differences in the volatile metabolites of wild and farmed sea bass have been found. A great deal of valuable information on sea bass volatile metabolites has been obtained, which can be useful in understanding certain aspects of the quality and safety of raw and processed sea bass. © 2015 Society of Chemical Industry.

USING SCHUMANN RESONANCE MEASUREMENTS FOR CONSTRAINING THE WATER ABUNDANCE ON THE GIANT PLANETS-IMPLICATIONS FOR THE SOLAR SYSTEM'S FORMATION

Energy Technology Data Exchange (ETDEWEB)

Simoes, Fernando; Pfaff, Robert; Klenzing, Jeffrey; Freudenreich, Henry; Bromund, Kenneth; Martin, Steven; Rowland, Douglas [NASA/GSFC, Heliophysics Science Division, Space Weather Laboratory (Code 674), Greenbelt, MD (United States); Hamelin, Michel; Berthelier, Jean-Jacques [LATMOS/IPSL, UPMC, Paris (France); Beghin, Christian; Lebreton, Jean-Pierre [LPC2E, CNRS/Universite d' Orleans (France); Grard, Rejean [ESA/ESTEC, Research Scientific Support Department, Noordwijk (Netherlands); Sentman, Davis [Institute of Geophysics, University of Alaska Fairbanks, Fairbanks, AK (United States); Takahashi, Yukihiro [Department of Geophysics, Tohoku University, Sendai (Japan); Yair, Yoav [Department Life Natural Sciences, Open University of Israel, Raanana (Israel)

2012-05-01

The formation and evolution of the solar system is closely related to the abundance of volatiles, namely water, ammonia, and methane in the protoplanetary disk. Accurate measurement of volatiles in the solar system is therefore important for understanding not only the nebular hypothesis and origin of life but also planetary cosmogony as a whole. In this work, we propose a new remote sensing technique to infer the outer planets' water content by measuring Tremendously and Extremely Low Frequency (TLF-ELF) electromagnetic wave characteristics (Schumann resonances) excited by lightning in their gaseous envelopes. Schumann resonance detection can be potentially used for constraining the uncertainty of volatiles of the giant planets, mainly Uranus and Neptune, because such TLF-ELF wave signatures are closely related to the electric conductivity profile and water content.

Effect of the type of frying culinary fat on volatile compounds isolated in fried pork loin chops by using SPME-GC-MS.

Science.gov (United States)

Ramírez, María Rosario; Estévez, Mario; Morcuende, David; Cava, Ramón

2004-12-15

The effect of the type of frying culinary fat (olive oil, sunflower oil, butter, and pig lard) on volatile compounds isolated from fried pork loin chops (m. Longissimus dorsi) was measured by SPME-GC-MS. Frying modified the fatty acid composition of lipids from pork loin chops, which tended to be similar to that of the culinary fat used to fry. Volatile compounds formed from the oxidation of fatty acids increased, such as aldehydes, ketones, alcohols, and hydrocarbons. Besides, each culinary fat used modified the volatile profiles in fried meat differently. Sunflower oil-fried pork loin chops presented the highest aldehyde aliphatic content, probably due to their highest content of polyunsaturated acids. Hexanal, the most abundant aldehyde in fried samples, presented the most elevated content in sunflower oil-fried pork loin chops. In addition, these samples presented more heterocyclic compounds from the Maillard reaction than other fried samples. Volatiles detected in olive oil-fried pork loin chops were mainly lipid-derived compounds such as pentan-1-ol, hexanal, hept-2-enal, nonanal, decanal, benzaldehyde, and nonan-2-one. Butter-fried pork loins were abundant in ketones with a high number of carbons (heptan-2-one, nonan-2-one, undecan-2-one, tridecanone, and heptadecan-2-one). Pig lard-fried pork loin chops presented some Strecker aldehydes isolated in only these samples, such as 2-methylbutanal and 3-(methylthio)propanal, and a sulfur compound (dimethyl disulfide) related to Strecker aldehydes.

The Ratio between Field Attractive and Background Volatiles Encodes Host-Plant Recognition in a Specialist Moth.

Science.gov (United States)

Knudsen, Geir K; Norli, Hans R; Tasin, Marco

2017-01-01

Volatiles emitted by plants convey an array of information through different trophic levels. Animals such as host-seeking herbivores encounter plumes with filaments from both host and non-host plants. While studies showed a behavioral effect of non-host plants on herbivore host location, less information is available on how a searching insect herbivore perceives and flies upwind to a host-plant odor plume within a background of non-host volatiles. We hypothesized here that herbivorous insects in search of a host-plant can discriminate plumes of host and non-host plants and that the taxonomic relatedness of the non-host have an effect on finding the host. We also predicted that the ratio between certain plant volatiles is cognized as host-plant recognition cue by a receiver herbivorous insect. To verify these hypotheses we measured the wind tunnel response of the moth Argyresthia conjugella to the host plant rowan, to non-host plants taxonomically related (Rosaceae, apple and pear) or unrelated to the host (Pinaceae, spruce) and to binary combination of host and non-host plants. Volatiles were collected from all plant combinations and delivered to the test insect via an ultrasonic sprayer as an artificial plume. While the response to the rowan as a plant was not affected by the addition of any of the non-host plants, the attraction to the corresponding sprayed headspace decreased when pear or apple but not spruce were added to rowan. A similar result was measured toward the odor exiting a jar where freshly cut plant material of apple or pear or spruce was intermixed with rowan. Dose-response gas-chromatography coupled to electroantennography revealed the presence of seven field attractive and seven background non-attractive antennally active compounds. Although the abundance of field attractive and of some background volatiles decreased in all dual combinations in comparison with rowan alone, an increased amount of the background compounds (3E)-4,8-Dimethyl-1

Natural Variation of Volatile Compounds in Virgin Olive Oil Analyzed by HS-SPME/GC-MS-FID

Directory of Open Access Journals (Sweden)

Carlos Sanz

2018-04-01

Full Text Available Virgin olive oil is unique among plant oils for its high levels of oleic acid, and the presence of a wide range of minor components, which are responsible for both its health-promoting properties and characteristic aroma, and only produced when olives are crushed during the industrial process used for oil production. The genetic variability of the major volatile compounds comprising the oil aroma was studied in a representative sample of olive cultivars from the World Olive Germplasm Collection (IFAPA, Cordoba, Spain, by means of the headspace solid-phase microextraction/gas chromatography–mass spectrometry–flame ionization detection (HS-SPME/GC-MS-FID. The analytical data demonstrated that a high variability is found for the content of volatile compounds in olive species, and that most of the volatile compounds found in the oils were synthesized by the enzymes included in the so-called lipoxygenase pathway. Multivariate analysis allowed the identification of cultivars that are particularly interesting, in terms of volatile composition and presumed organoleptic quality, which can be used both to identify old olive cultivars that give rise to oils with a high organoleptic quality, and in parent selection for olive breeding programs.

Impact of elevated CO2 and O3 concentrations on biogenic volatile organic compounds emissions from Ginkgo biloba.

Science.gov (United States)

Li, Dewen; Chen, Ying; Shi, Yi; He, Xingyuan; Chen, Xin

2009-04-01

In natural environment with ambient air, ginkgo trees emitted volatile organic compounds 0.18 microg g(-1) h(-1) in July, and 0.92 microg g(-1) h(-1) in September. Isoprene and limonene were the most abundant detected compounds. In September, alpha-pinene accounted for 22.5% of the total. Elevated CO(2) concentration in OTCs increased isoprene emission significantly in July (pemission was enhanced in July and decreased in September by elevated CO(2). Exposed to elevated O(3) increased the isoprene and monoterpenes emissions in July and September, and the total volatile organic compounds emission rates were 0.48 microg g(-1) h(-1) (in July) and 2.24 microg g(-1) h(-1) (in September), respectively. The combination of elevated CO(2) and O(3) did not have any effect on biogenic volatile organic compounds emissions, except increases of isoprene and Delta3-carene in September.

Volatility and variance swaps : A comparison of quantitative models to calculate the fair volatility and variance strike

OpenAIRE

Röring, Johan

2017-01-01

Volatility is a common risk measure in the field of finance that describes the magnitude of an asset’s up and down movement. From only being a risk measure, volatility has become an asset class of its own and volatility derivatives enable traders to get an isolated exposure to an asset’s volatility. Two kinds of volatility derivatives are volatility swaps and variance swaps. The problem with volatility swaps and variance swaps is that they require estimations of the future variance and volati...

Endogenous Lunar Volatiles

Science.gov (United States)

McCubbin, F. M.; Liu, Y.; Barnes, J. J.; Anand, M.; Boyce, J. W.; Burney, D.; Day, J. M. D.; Elardo, S. M.; Hui, H.; Klima, R. L.; Magna, T.; Ni, P.; Steenstra, E.; Tartèse, R.; Vander Kaaden, K. E.

2018-04-01

This abstract discusses numerous outstanding questions on the topic of endogenous lunar volatiles that will need to be addressed in the coming years. Although substantial insights into endogenous lunar volatiles have been gained, more work remains.

An upper limit on the sulphur abundance in HE 1327-2326

Science.gov (United States)

Bonifacio, P.; Caffau, E.; Venn, K. A.; Lambert, D. L.

2012-08-01

Context. Star HE 1327-2326 is a unique object, with the lowest measured iron abundance ([Fe/H] ~ -6) and a peculiar chemical composition that includes large overabundances of C, N, and O with respect to iron. One important question is whether the chemical abundances in this star reflect the chemical composition of the gas cloud from which it was formed or if they have been severely affected by other processes, such as dust-gas winnowing. Aims: We measure or provide an upper limit to the abundance of the volatile element sulphur, which can help to discriminate between the two scenarios. Methods: We observed HE 1327-2326 with the high resolution infra-red spectrograph CRIRES at the VLT to observe the S i lines of Multiplet 3 at 1045 nm. Results: We do not detect the S i line. A 3σ upper limit on the equivalent width (EW) of any line in our spectrum is EW winnowing, and the evidence coming from other elements (e.g., Na and Ti) is also inconclusive or contradictory. The formation of dust in the atmosphere versus an origin of the metals in a metal-poor supernova with extensive "fall-back" are not mutually exclusive. It is possible that dust formation distorts the peculiar abundance pattern created by a supernova with fall-back, thus the abundance ratios in HE 1327-2326 may be used to constrain the properties of the supernova(e) that produced its metals, but with some caution. Based on spectra obtained with CRIRES at the 8.2 m Antu ESO telescope, programme 386.D-0095.

High precision isotopic ratio analysis of volatile metal chelates

International Nuclear Information System (INIS)

Hachey, D.L.; Blais, J.C.; Klein, P.D.

1980-01-01

High precision isotope ratio measurements have been made for a series of volatile alkaline earth and transition metal chelates using conventional GC/MS instrumentation. Electron ionization was used for alkaline earth chelates, whereas isobutane chemical ionization was used for transition metal studies. Natural isotopic abundances were determined for a series of Mg, Ca, Cr, Fe, Ni, Cu, Cd, and Zn chelates. Absolute accuracy ranged between 0.01 and 1.19 at. %. Absolute precision ranged between +-0.01-0.27 at. % (RSD +- 0.07-10.26%) for elements that contained as many as eight natural isotopes. Calibration curves were prepared using natural abundance metals and their enriched 50 Cr, 60 Ni, and 65 Cu isotopes covering the range 0.1-1010.7 at. % excess. A separate multiple isotope calibration curve was similarly prepared using enriched 60 Ni (0.02-2.15 at. % excess) and 62 Ni (0.23-18.5 at. % excess). The samples were analyzed by GC/CI/MS. Human plasma, containing enriched 26 Mg and 44 Ca, was analyzed by EI/MS. 1 figure, 5 tables

Emerging non-volatile memories

CERN Document Server

Hong, Seungbum; Wouters, Dirk

2014-01-01

This book is an introduction to the fundamentals of emerging non-volatile memories and provides an overview of future trends in the field. Readers will find coverage of seven important memory technologies, including Ferroelectric Random Access Memory (FeRAM), Ferromagnetic RAM (FMRAM), Multiferroic RAM (MFRAM), Phase-Change Memories (PCM), Oxide-based Resistive RAM (RRAM), Probe Storage, and Polymer Memories. Chapters are structured to reflect diffusions and clashes between different topics. Emerging Non-Volatile Memories is an ideal book for graduate students, faculty, and professionals working in the area of non-volatile memory. This book also: Covers key memory technologies, including Ferroelectric Random Access Memory (FeRAM), Ferromagnetic RAM (FMRAM), and Multiferroic RAM (MFRAM), among others. Provides an overview of non-volatile memory fundamentals. Broadens readers' understanding of future trends in non-volatile memories.

Volatility Exposure for Strategic Asset Allocation

OpenAIRE

Briere, Marie; Burgues, Alexandre; Signori, Ombretta

2008-01-01

This paper examines the advantages of incorporating strategic exposure to equity volatility into the investment-opportunity set of a long-term equity investor. We consider two standard volatility investments: implied volatility and volatility risk premium strategies. To calibrate and assess the risk/return profile of the portfolio, we present an analytical framework offering pragmatic solutions for long-term investors seeking exposure to volatility. The benefit of volatility exposure for a co...

Origin of Volatiles in Earth: Indigenous Versus Exogenous Sources Based on Highly Siderophile, Volatile Siderophile, and Light Volatile Elements

Science.gov (United States)

Righter, K.; Danielson, L.; Pando, K. M.; Marin, N.; Nickodem, K.

2015-01-01

Origin of Earth's volatiles has traditionally been ascribed to late accretion of material after major differentiation events - chondrites, comets, ice or other exogenous sources. A competing theory is that the Earth accreted its volatiles as it was built, thus water and other building blocks were present early and during differentiation and core formation (indigenous). Here we discuss geochemical evidence from three groups of elements that suggests Earth's volatiles were acquired during accretion and did not require additional sources after differentiation.

Apatite: A New Tool For Understanding The Temporal Variability Of Magmatic Volatile Contents

Science.gov (United States)

Stock, M. J.; Humphreys, M.; Smith, V.; Pyle, D. M.; Isaia, R.

2015-12-01

The apatite crystal structure is capable of incorporating H2O, F and Cl, as well as trace CO2 and sulphur. These can be related to parental magma compositions through application of a series of pressure and temperature-dependent exchange reactions (Piccoli and Candela, 1994), permitting apatite crystals to preserve a record of all major volatile species in the melt. Furthermore, due to the general incompatibility of P in other rock-forming minerals, apatite is ubiquitous in igneous systems and often begins crystallising early, such that apatite inclusions within phenocrysts record melt volatile contents throughout magmatic differentiation. In this work, we compare the compositions of apatite inclusions and microphenocrysts with pyroxene-hosted melt inclusions from the Astroni 1 eruption of Campi Flegrei, Italy. These data are coupled with magmatic differentiation models (Gualda et al., 2012), experimental volatile solubility data (Webster et al., 2014) and thermodynamic models of apatite compositional variations (Piccoli and Candela, 1994) to determine a time-series of magmatic volatile evolution in the build-up to eruption. We find that apatite halogen/OH ratios decreased through magmatic differentiation, while melt inclusion F and Cl concentrations increased. Melt inclusion H2O contents are constant at ~2.5 wt%. These data are best explained by volatile-undersaturated differentiation over most of the crystallisation history of the Astroni 1 melt, with melt inclusion H2O contents reset during ascent, due to rapid H diffusion through the phenocryst hosts (Woods et al., 2000). Given the rapid diffusivity of volatiles in apatite (Brenan, 1993), preservation of undersaturated compositions in microphenocrysts suggests that saturation was only achieved a few days to months before eruption and that it may have been the transition into a volatile-saturated state that ultimately triggered eruption. Piccoli and Candela, 1994. Am. J. of Sc., 294, 92-135. Gualda et al., 2012

Determination of volatile compounds in four commercial samples of Japanese green algae using solid phase microextraction gas chromatography mass spectrometry.

Science.gov (United States)

Yamamoto, Masayoshi; Baldermann, Susanne; Yoshikawa, Keisuke; Fujita, Akira; Mase, Nobuyuki; Watanabe, Naoharu

2014-01-01

Green algae are of great economic importance. Seaweed is consumed fresh or as seasoning in Japan. The commercial value is determined by quality, color, and flavor and is also strongly influenced by the production area. Our research, based on solid phase microextraction gas chromatography mass spectrometry (SPME-GC-MS), has revealed that volatile compounds differ intensely in the four varieties of commercial green algae. Accordingly, 41 major volatile compounds were identified. Heptadecene was the most abundant compound from Okayama (Ulva prolifera), Tokushima (Ulva prolifera), and Ehime prefecture (Ulva linza). Apocarotenoids, such as ionones, and their derivatives were prominent volatiles in algae from Okayama (Ulva prolifera) and Tokushima prefecture (Ulva prolifera). Volatile, short chained apocarotenoids are among the most potent flavor components and contribute to the flavor of fresh, processed algae, and algae-based products. Benzaldehyde was predominant in seaweed from Shizuoka prefecture (Monostroma nitidum). Multivariant statistical analysis (PCA) enabled simple discrimination of the samples based on their volatile profiles. This work shows the potential of SPME-GC-MS coupled with multivariant analysis to discriminate between samples of different geographical and botanical origins and form the basis for development of authentication methods of green algae products, including seasonings.

CHEMICAL ABUNDANCES IN THE EXTERNALLY POLLUTED WHITE DWARF GD 40: EVIDENCE OF A ROCKY EXTRASOLAR MINOR PLANET

International Nuclear Information System (INIS)

Klein, B.; Jura, M.; Zuckerman, B.; Melis, C.; Koester, D.

2010-01-01

We present Keck/High Resolution Echelle Spectrometer data with model atmosphere analysis of the helium-dominated polluted white dwarf GD 40, in which we measure atmospheric abundances relative to helium of nine elements: H, O, Mg, Si, Ca, Ti, Cr, Mn, and Fe. Apart from hydrogen, whose association with the other contaminants is uncertain, this material most likely accreted from GD 40's circumstellar dust disk whose existence is demonstrated by excess infrared emission. The data are best explained by accretion of rocky planetary material, in which heavy elements are largely contained within oxides, derived from a tidally disrupted minor planet at least the mass of Juno, and probably as massive as Vesta. The relatively low hydrogen abundance sets an upper limit of 10% water by mass in the inferred parent body, and the relatively high abundances of refractory elements, Ca and Ti, may indicate high-temperature processing. While the overall constitution of the parent body is similar to the bulk Earth being over 85% by mass composed of oxygen, magnesium, silicon, and iron, we find n(Si)/n(Mg) = 0.30 ± 0.11, significantly smaller than the ratio near unity for the bulk Earth, chondrites, the Sun, and nearby stars. This result suggests that differentiation occurred within the parent body.

Volatility transmission and volatility impulse response functions in European electricity forward markets

International Nuclear Information System (INIS)

Le Pen, Yannick; Sevi, Benoit

2008-01-01

Using daily data from March 2001 to June 2005, we estimate a VAR-BEKK model and find evidence of return and volatility spillovers between the German, the Dutch and the British forward electricity markets. We apply Hafner and Herwartz [2006, Journal of International Money and Finance 25, 719-740] Volatility Impulse Response Function(VIRF) to quantify the impact of shock on expected conditional volatility. We observe that a shock has a high positive impact only if its size is large compared to the current level of volatility. The impact of shocks are usually not persistent, which may be an indication of market efficiency. Finally, we estimate the density of the VIRF at different forecast horizon. These fitted distributions are asymmetric and show that extreme events are possible even if their probability is low. These results have interesting implications for market participants whose risk management policy is based on option prices which themselves depend on the volatility level. (authors)

The volatility of HOL

International Nuclear Information System (INIS)

Wren, D.J.; Sanipelli, G.

1985-01-01

The volatility of HOI has been measured using a mass spectrometer to analyze the gas phase above an aqueous solution. The HOI in solution was generated continuously in a flow reactor that combined I/sup -/ and OCl/sup -/ solutions. The analysis has resulted in a lower limit of 6X10/sup 3/ mol . dm/sup -3/ . atm/sup -1/ for the equilibrium constant for the reaction HOI(g)/equilibrium/HOI(aq). This value is a factor 30 greater than the best previous estimate. This new limit for HOI volatility results in higher total iodine partition coefficients, particularly for solutions with pH>8. The upper limit for the equilibrium constant is consistent with essentially zero volatility for HOI. The effect of HOI volatility on total iodine volatility is briefly discussed as a function of solution chemistry and kinetics

Differentiation history of small bodies in the solar system: the howardite and mesosiderite meteorite parent bodies

International Nuclear Information System (INIS)

Mittlefehldt, D.W.

1978-01-01

Mesosiderites and howardites are regolith samples of differentiated asteroids. Instrumental neutron activation analysis (INAA) data on whole rock howardites and mesosiderite silicates show that the composition of howardites and mesosiderites are similar, and intermediate between those of eucrites and diogenites. The mesosiderites Mincy, Lowicz and Veramin show an enrichment in light REE and have an REE pattern that is qualitatively similar to that in terrestrial basalts thought to have been formed by small degrees of partial melting. Attempts to model the REE abundances in these mesosiderites indicates that they most likely formed by approx. 2 to 4% partial melting of a source containing low abundances of the rare earths. Since numerous properties separate mesosiderite silicates from howardites, it is clear that they are not samples of a well-mixed regolith from a single parent body. If regolith stirring is efficient on small parent bodies, then mesosiderites and howardites originated on separate parent bodies. Rare earth element patterns give evidence for remelting and fractional crystallization of preexisting cumulates and sequential melting episodes. The mesosiderites appear to contain a slightly greater abundance of diogenite-like material and certainly contain a greater abundance of large olivine clasts. These observations suggest that the mesosiderite parent body crust was more complexly fractionated than the howardite parent body crust. The latter appears to have been dominated by quenched basalt flows

Volatility measurement of atmospheric submicron aerosols in an urban atmosphere in southern China

Directory of Open Access Journals (Sweden)

L.-M. Cao

2018-02-01

Full Text Available Aerosol pollution has been a very serious environmental problem in China for many years. The volatility of aerosols can affect the distribution of compounds in the gas and aerosol phases, the atmospheric fates of the corresponding components, and the measurement of the concentration of aerosols. Compared to the characterization of chemical composition, few studies have focused on the volatility of aerosols in China. In this study, a thermodenuder aerosol mass spectrometer (TD-AMS system was deployed to study the volatility of non-refractory submicron particulate matter (PM1 species during winter in Shenzhen. To our knowledge, this paper is the first report of the volatilities of aerosol chemical components based on a TD-AMS system in China. The average PM1 mass concentration during the experiment was 42.7±20.1 µg m−3, with organic aerosol (OA being the most abundant component (43.2 % of the total mass. The volatility of chemical species measured by the AMS varied, with nitrate showing the highest volatility, with a mass fraction remaining (MFR of 0.57 at 50 °C. Organics showed semi-volatile characteristics (the MFR was 0.88 at 50 °C, and the volatility had a relatively linear correlation with the TD temperature (from the ambient temperature to 200 °C, with an evaporation rate of 0.45 % °C−1. Five subtypes of OA were resolved from total OA using positive matrix factorization (PMF for data obtained under both ambient temperature and high temperatures through the TD, including a hydrocarbon-like OA (HOA, accounting for 13.5 %, a cooking OA (COA, 20.6 %, a biomass-burning OA (BBOA, 8.9 %, and two oxygenated OAs (OOAs: a less-oxidized OOA (LO-OOA, 39.1 % and a more-oxidized OOA (MO-OOA, 17.9 %. Different OA factors presented different volatilities, and the volatility sequence of the OA factors at 50 °C was HOA (MFR of 0.56  >  LO-OOA (0.70  >  COA (0.85  ≈  BBOA (0.87�

Volatility Mean Reversion and the Market Price of Volatility Risk

NARCIS (Netherlands)

Boswijk, H.P.

2001-01-01

This paper analyzes sources of derivative pricing errors in a stochastic volatility model estimated on stock return data. It is shown that such pricing errors may reflect the existence of a market price of volatility risk, but also may be caused by estimation errors due to a slow mean reversion in

Cost Linkages Transmit Volatility Across Markets

DEFF Research Database (Denmark)

Nguyen, Daniel Xuyen; Schaur, Georg

We present and test a model relating a firm's idiosyncratic cost, its exporting status, and the volatilities of its domestic and export sales. In prior models of trade, supply costs for domestic and exports were linear and thus additively separable. We introduce a nonlinear cost function in order...... to link the domestic and export supply costs. This theoretical contribution has two new implications for the exporting firm. First, the demand volatility in the foreign market now directly affects the firm's domestic sales volatility. Second, firms hedge domestic demand volatility with exports. The model...... has several testable predictions. First, larger firms have lower total and domestic sales volatilities. Second, foreign market volatility increases domestic sales volatilities for exporters. Third, exporters allocate output across both markets in order to reduce total sales volatility. We find...

Time-Varying Periodicity in Intraday Volatility

DEFF Research Database (Denmark)

Andersen, Torben Gustav; Thyrsgaard, Martin; Todorov, Viktor

We develop a nonparametric test for deciding whether return volatility exhibits time-varying intraday periodicity using a long time-series of high-frequency data. Our null hypothesis, commonly adopted in work on volatility modeling, is that volatility follows a stationary process combined...... with a constant time-of-day periodic component. We first construct time-of-day volatility estimates and studentize the high-frequency returns with these periodic components. If the intraday volatility periodicity is invariant over time, then the distribution of the studentized returns should be identical across...... with estimating volatility moments through their sample counterparts. Critical values are computed via easy-to-implement simulation. In an empirical application to S&P 500 index returns, we find strong evidence for variation in the intraday volatility pattern driven in part by the current level of volatility...

Influence of yeast strain, canopy management, and site on the volatile composition and sensory attributes of cabernet sauvignon wines from Western Australia.

Science.gov (United States)

Robinson, Anthony L; Boss, Paul K; Heymann, Hildegarde; Solomon, Peter S; Trengove, Robert D

2011-04-13

Understanding what factors are the major influences on wine composition will assist in the successful management of grape composition in the vineyard and/or variables in the winery to produce wines with specific sensory attributes. A recently developed analytical method [headspace solid-phase microextraction comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry] was employed to analyze over 350 volatile compounds in research scale wines and was combined with descriptive sensory analysis. Both compositional and sensory results showed significant differences among the wines, and in many cases, multiple factors influenced the abundance of wine volatile compounds. Site had the most significant influence on sensory scores and wine composition, followed by canopy management. Unexpectedly, yeast strain had no significant sensory effect despite the fact that a number of volatile compounds were significantly different in the wines made from different strains. PLS analysis, combining the sensory and chemical analyses, also supports the concept of volatile compound interactions contributing to the aroma characteristics of Cabernet Sauvignon wine.

Bias correction in the realized stochastic volatility model for daily volatility on the Tokyo Stock Exchange

Science.gov (United States)

Takaishi, Tetsuya

2018-06-01

The realized stochastic volatility model has been introduced to estimate more accurate volatility by using both daily returns and realized volatility. The main advantage of the model is that no special bias-correction factor for the realized volatility is required a priori. Instead, the model introduces a bias-correction parameter responsible for the bias hidden in realized volatility. We empirically investigate the bias-correction parameter for realized volatilities calculated at various sampling frequencies for six stocks on the Tokyo Stock Exchange, and then show that the dynamic behavior of the bias-correction parameter as a function of sampling frequency is qualitatively similar to that of the Hansen-Lunde bias-correction factor although their values are substantially different. Under the stochastic diffusion assumption of the return dynamics, we investigate the accuracy of estimated volatilities by examining the standardized returns. We find that while the moments of the standardized returns from low-frequency realized volatilities are consistent with the expectation from the Gaussian variables, the deviation from the expectation becomes considerably large at high frequencies. This indicates that the realized stochastic volatility model itself cannot completely remove bias at high frequencies.

Attraction of Callosobruchus maculatus (F.) (Coleoptera: Bruchidae) to four varieties of Lathyrus sativus L. seed volatiles.

Science.gov (United States)

Adhikary, P; Mukherjee, A; Barik, A

2015-04-01

Callosobruchus maculatus (F.) (Coleoptera: Bruchidae) is an important stored grain pest of Lathyrus sativus L. (Leguminosae), commonly known as khesari, in India, Bangladesh and Ethiopia. Volatiles were collected from four varieties, i.e., Bio L 212 Ratan, Nirmal B-1, WBK-14-7 and WBK-13-1 of uninfested khesari seeds, and subsequently identified and quantified by gas chromatography mass spectrometry and gas chromatography flame ionization detector analyses, respectively. A total of 23 volatiles were identified in the four varieties of khesari seeds. In Bio L 212 Ratan and WBK-13-1 seeds, nonanal was the most abundant followed by farnesyl acetone; whereas farnesyl acetone was predominant followed by nonanal in Nirmal B-1 and WBK-14-7 khesari seeds. The olfactory responses of female C. maculatus toward volatile blends from four varieties of khesari seeds, and individual synthetic compounds and their combinations were examined through Y-shaped glass tube olfactometer bioassays. Callosobruchus maculatus showed significant preference for the whole volatile blends from Bio L 212 Ratan seeds compared to whole volatile blends from other three varieties. The insect exhibited attraction to five individual synthetic compounds, 3-octanone, 3-octanol, linalool oxide, 1-octanol and nonanal. A synthetic blend of 448, 390, 1182, 659 and 8114 ng/20 μl methylene chloride of 3-octanone, 3-octanol, linalool oxide, 1-octanol and nonanal, respectively, was most attractive to C. maculatus, and this combination might be used for insect pest management program such as baited traps.

Forecasting volatility of crude oil markets

International Nuclear Information System (INIS)

Kang, Sang Hoon; Kang, Sang-Mok; Yoon, Seong-Min

2009-01-01

This article investigates the efficacy of a volatility model for three crude oil markets - Brent, Dubai, and West Texas Intermediate (WTI) - with regard to its ability to forecast and identify volatility stylized facts, in particular volatility persistence or long memory. In this context, we assess persistence in the volatility of the three crude oil prices using conditional volatility models. The CGARCH and FIGARCH models are better equipped to capture persistence than are the GARCH and IGARCH models. The CGARCH and FIGARCH models also provide superior performance in out-of-sample volatility forecasts. We conclude that the CGARCH and FIGARCH models are useful for modeling and forecasting persistence in the volatility of crude oil prices. (author)

Forecasting volatility of crude oil markets

Energy Technology Data Exchange (ETDEWEB)

Kang, Sang Hoon [Department of Business Administration, Gyeongsang National University, Jinju, 660-701 (Korea); Kang, Sang-Mok; Yoon, Seong-Min [Department of Economics, Pusan National University, Busan, 609-735 (Korea)

2009-01-15

This article investigates the efficacy of a volatility model for three crude oil markets - Brent, Dubai, and West Texas Intermediate (WTI) - with regard to its ability to forecast and identify volatility stylized facts, in particular volatility persistence or long memory. In this context, we assess persistence in the volatility of the three crude oil prices using conditional volatility models. The CGARCH and FIGARCH models are better equipped to capture persistence than are the GARCH and IGARCH models. The CGARCH and FIGARCH models also provide superior performance in out-of-sample volatility forecasts. We conclude that the CGARCH and FIGARCH models are useful for modeling and forecasting persistence in the volatility of crude oil prices. (author)

Perchlorate and Volatiles in the Brine of Lake Vida (antarctica): Implication for the Analysis of Mars Sediments

Science.gov (United States)

Kenig, F. P. H.; Chou, L.; McKay, C.; Jackson, W. A.; Doran, P. T.; Murray, A. E.; Fritsen, C. H.

2015-12-01

A cold (-13.4 °C), saline (188 psu) evaporative brine is encapsulated in the thick (> 27 m) ice of Lake Vida (McMurdo Dry Valleys, Antarctica). The Lake Vida brine (LVBr), which contains abundant dissolved organic carbon (48.2 mmol/L), support an active but slow microbial community. LVBr contains oxychlorines with 50 μg/L of perchlorate and 11 μg/L of chlorate. The McMurdo Dry Valleys have often been considered as a good Mars analog. The oxychlorine-rich brine of Lake Vida constitutes a potential equivalent to perchlorate-rich preserved saline liquid water on Mars. We report here on the artifacts created by oxychlorines upon analysis of volatiles and volatile organic compounds (VOCs) of LVBr by direct immersion (DI) and head space (HS) solid phase micro extraction (SPME) gas chromatography-mass spectrometry (GCMS). We compare analytical blanks to a standard containing 40 μg/L of perchlorate and to actual LVBr sample runs. All blanks, perchlorate blanks and samples were analyzed using two types of SPME fibers, CarboxenTM/polydimethylsiloxane (PDMS) and divinylbenzene (DVB)/ PDMS. The similarities and differences between our results and those obtained by the Sample Analysis at Mars instruments of the rover Curiosity are discussed. The volatiles evolved from LVBr upon analysis with DI- and HS-SPME GCMS are dominated by CO2, dichloromethane, HCl, and volatile organic sulfur compounds (VOSCs, such as DMS, DMDS). The volatiles also include oxygenated compounds such as acids and ketones, aromatic compounds, hydrocarbons, chlorinated compounds (dominated by dichloromethane). Apart from the VOSCs, short chain hydrocarbons and some functionalized compounds derived from the brine itself, all compounds observed are artifacts formed upon oxychlorine breakdown in the injector of the GCMS. The distribution of aromatic compounds seems to be directly dependant on the type of SPME fiber used. The perchlorate blanks show a clear pattern of carbon limitation, likely affecting the

Alternative Asymmetric Stochastic Volatility Models

NARCIS (Netherlands)

M. Asai (Manabu); M.J. McAleer (Michael)

2010-01-01

textabstractThe stochastic volatility model usually incorporates asymmetric effects by introducing the negative correlation between the innovations in returns and volatility. In this paper, we propose a new asymmetric stochastic volatility model, based on the leverage and size effects. The model is

Symptoms of mothers and infants related to total volatile organic compounds in household products

OpenAIRE

Farrow, A; Taylor, H; Northstone, K; Golding, J

2003-01-01

The authors sought to determine whether reported symptoms of mothers and infants were associated significantly with the use of household products that raised indoor levels of total volatile organic compounds (TVOCs). Data collected from 170 homes within the Avon Longitudinal Study of Parents and Children (ALSPAC: a large birth cohort of more than 10,000) had determined which household products were associated with the highest levels of TVOCs. The latter data were collected over a period that ...

Occurrence and abatement of volatile sulfur compounds during biogas production.

Science.gov (United States)

Andersson, Fräs Annika T; Karlsson, Anna; Svensson, Bo H; Ejlertsson, Jörgen

2004-07-01

Volatile sulfur compounds (VSCs) in biogas originating from a biogas production plant and from a municipal sewage water treatment plant were identified. Samples were taken at various stages of the biogas-producing process, including upgrading the gas to vehicle-fuel quality. Solid-phase microextraction was used for preconcentration of the VSCs, which were subsequently analyzed using gas chromatography in combination with mass spectrometry. Other volatile organic compounds present also were identified. The most commonly occurring VSCs in the biogas were hydrogen sulfide, carbonyl sulfide, methanethiol, dimethyl sulfide, and dimethyl disulfide, and hydrogen sulfide was not always the most abundant sulfur (S) compound. Besides VSCs, oxygenated organic compounds were commonly present (e.g., ketones, alcohols, and esters). The effect of adding iron chloride to the biogas reactor on the occurrence of VSCs also was investigated. It was found that additions of 500-g/m3 substrate gave an optimal removal of VSCs. Also, the use of a prefermentation step could reduce the amount of VSCs formed in the biogas process. Moreover, in the carbon dioxide scrubber used for upgrading the gas, VSCs were removed efficiently, leaving traces (ppbv levels). The scrubber also removed other organic compounds.

The Ratio between Field Attractive and Background Volatiles Encodes Host-Plant Recognition in a Specialist Moth

Directory of Open Access Journals (Sweden)

Geir K. Knudsen

2017-12-01

Full Text Available Volatiles emitted by plants convey an array of information through different trophic levels. Animals such as host-seeking herbivores encounter plumes with filaments from both host and non-host plants. While studies showed a behavioral effect of non-host plants on herbivore host location, less information is available on how a searching insect herbivore perceives and flies upwind to a host-plant odor plume within a background of non-host volatiles. We hypothesized here that herbivorous insects in search of a host-plant can discriminate plumes of host and non-host plants and that the taxonomic relatedness of the non-host have an effect on finding the host. We also predicted that the ratio between certain plant volatiles is cognized as host-plant recognition cue by a receiver herbivorous insect. To verify these hypotheses we measured the wind tunnel response of the moth Argyresthia conjugella to the host plant rowan, to non-host plants taxonomically related (Rosaceae, apple and pear or unrelated to the host (Pinaceae, spruce and to binary combination of host and non-host plants. Volatiles were collected from all plant combinations and delivered to the test insect via an ultrasonic sprayer as an artificial plume. While the response to the rowan as a plant was not affected by the addition of any of the non-host plants, the attraction to the corresponding sprayed headspace decreased when pear or apple but not spruce were added to rowan. A similar result was measured toward the odor exiting a jar where freshly cut plant material of apple or pear or spruce was intermixed with rowan. Dose-response gas-chromatography coupled to electroantennography revealed the presence of seven field attractive and seven background non-attractive antennally active compounds. Although the abundance of field attractive and of some background volatiles decreased in all dual combinations in comparison with rowan alone, an increased amount of the background compounds (3E-4

Determination of Volatile Compounds in Four Commercial Samples of Japanese Green Algae Using Solid Phase Microextraction Gas Chromatography Mass Spectrometry

Directory of Open Access Journals (Sweden)

Masayoshi Yamamoto

2014-01-01

Full Text Available Green algae are of great economic importance. Seaweed is consumed fresh or as seasoning in Japan. The commercial value is determined by quality, color, and flavor and is also strongly influenced by the production area. Our research, based on solid phase microextraction gas chromatography mass spectrometry (SPME-GC-MS, has revealed that volatile compounds differ intensely in the four varieties of commercial green algae. Accordingly, 41 major volatile compounds were identified. Heptadecene was the most abundant compound from Okayama (Ulva prolifera, Tokushima (Ulva prolifera, and Ehime prefecture (Ulva linza. Apocarotenoids, such as ionones, and their derivatives were prominent volatiles in algae from Okayama (Ulva prolifera and Tokushima prefecture (Ulva prolifera. Volatile, short chained apocarotenoids are among the most potent flavor components and contribute to the flavor of fresh, processed algae, and algae-based products. Benzaldehyde was predominant in seaweed from Shizuoka prefecture (Monostroma nitidum. Multivariant statistical analysis (PCA enabled simple discrimination of the samples based on their volatile profiles. This work shows the potential of SPME-GC-MS coupled with multivariant analysis to discriminate between samples of different geographical and botanical origins and form the basis for development of authentication methods of green algae products, including seasonings.

Volatile Composition and Enantioselective Analysis of Chiral Terpenoids of Nine Fruit and Vegetable Fibres Resulting from Juice Industry By-Products

Directory of Open Access Journals (Sweden)

Alexis Marsol-Vall

2017-01-01

Full Text Available Fruit and vegetable fibres resulting as by-products of the fruit juice industry have won popularity because they can be valorised as food ingredients. In this regard, bioactive compounds have already been studied but little attention has been paid to their remaining volatiles. Considering all the samples, 57 volatiles were identified. Composition greatly differed between citrus and noncitrus fibres. The former presented over 90% of terpenoids, with limonene being the most abundant and ranging from 52.7% in lemon to 94.0% in tangerine flesh. Noncitrus fibres showed more variable compositions, with the predominant classes being aldehydes in apple (57.5% and peach (69.7%, esters (54.0% in pear, and terpenoids (35.3% in carrot fibres. In addition, enantioselective analysis of some of the chiral terpenoids present in the fibre revealed that the enantiomeric ratio for selected compounds was similar to the corresponding volatile composition of raw fruits and vegetables and some derivatives, with the exception of terpinen-4-ol and α-terpineol, which showed variation, probably due to the drying process. The processing to which fruit residues were submitted produced fibres with low volatile content for noncitrus products. Otherwise, citrus fibres analysed still presented a high volatile composition when compared with noncitrus ones.

Parental material and cultivation determine soil bacterial community structure and fertility.

Science.gov (United States)

Sun, Li; Gao, Jusheng; Huang, Ting; Kendall, Joshua R A; Shen, Qirong; Zhang, Ruifu

2015-01-01

Microbes are the key components of the soil environment, playing important roles during soil development. Soil parent material provides the foundation elements that comprise the basic nutritional environment for the development of microbial community. After 30 years artificial maturation of cultivation, the soil developments of three different parental materials were evaluated and bacterial community compositions were investigated using the high-throughput sequencing approach. Thirty years of cultivation increased the soil fertility and soil microbial biomass, richness and diversity, greatly changed the soil bacterial communities, the proportion of phylum Actinobacteria decreased significantly, while the relative abundances of the phyla Acidobacteria, Chloroflexi, Gemmatimonadetes, Armatimonadetes and Nitrospira were significantly increased. Soil bacterial communities of parental materials were separated with the cultivated ones, and comparisons of different soil types, granite soil and quaternary red clay soil were similar and different with purple sandy shale soil in both parental materials and cultivated treatments. Bacterial community variations in the three soil types were affected by different factors, and their alteration patterns in the soil development also varied with soil type. Soil properties (except total potassium) had a significant effect on the soil bacterial communities in all three soil types and a close relationship with abundant bacterial phyla. The amounts of nitrogen-fixing bacteria as well as the abundances of the nifH gene in all cultivated soils were higher than those in the parental materials; Burkholderia and Rhizobacte were enriched significantly with long-term cultivation. The results suggested that crop system would not deplete the nutrients of soil parental materials in early stage of soil maturation, instead it increased soil fertility and changed bacterial community, specially enriched the nitrogen-fixing bacteria to accumulate

Impact of microorganism on polonium volatilization

International Nuclear Information System (INIS)

Momoshima, N.; Ishida, A.; Fukuda, A.; Yoshinaga, C.

2007-01-01

Volatilization of polonium by microorganisms, Chromobacterium violaceum, Escherichia coli and Bacillus subtilis was examined for pure cultures in LB medium at 30 deg C, showing relative Po emission intensity 100, 10 and 1, respectively. Chromobacterium violaceum pre-cultured in LB medium without Po and suspended in water with Po showed high Po volatilization in spite of poor nutriment condition. Antibiotics inhibit volatilization of Po and cultivation at low temperature greatly reduced volatilization. The results strongly support the biological effects on Po volatilization. (author)

The origin of volatile element depletion in early solar system material: Clues from Zn isotopes in chondrules

Science.gov (United States)

Pringle, Emily A.; Moynier, Frédéric; Beck, Pierre; Paniello, Randal; Hezel, Dominik C.

2017-06-01

Volatile lithophile elements are depleted in the different planetary materials to various degrees, but the origin of these depletions is still debated. Stable isotopes of moderately volatile elements such as Zn can be used to understand the origin of volatile element depletions. Samples with significant volatile element depletions, including the Moon and terrestrial tektites, display heavy Zn isotope compositions (i.e. enrichment of 66Zn vs. 64Zn), consistent with kinetic Zn isotope fractionation during evaporation. However, Luck et al. (2005) found a negative correlation between δ66Zn and 1/[Zn] between CI, CM, CO, and CV chondrites, opposite to what would be expected if evaporation caused the Zn abundance variations among chondrite groups. We have analyzed the Zn isotope composition of multiple samples of the major carbonaceous chondrite classes: CI (1), CM (4), CV (2), CO (4), CB (2), CH (2), CK (4), and CK/CR (1). The bulk chondrites define a negative correlation in a plot of δ66Zn vs 1/[Zn], confirming earlier results that Zn abundance variations among carbonaceous chondrites cannot be explained by evaporation. Exceptions are CB and CH chondrites, which display Zn systematics consistent with a collisional formation mechanism that created enrichment in heavy Zn isotopes relative to the trend defined by CI-CK. We further report Zn isotope analyses of chondrite components, including chondrules from Allende (CV3) and Mokoia (CV3), as well as an aliquot of Allende matrix. All chondrules are enriched in light Zn isotopes (∼500 ppm on 66Zn/64Zn) relative to the bulk, contrary to what would be expected if Zn were depleted during evaporation, on the other hand the matrix has a complementary heavy isotope composition. We report sequential leaching experiments in un-equilibrated ordinary chondrites, which show sulfides are isotopically heavy compared to silicates and the bulk meteorite by ca. +0.65 per mil on 66Zn/64Zn. We suggest isotopically heavy sulfides were

Studying Plant–Insect Interactions with Solid Phase Microextraction: Screening for Airborne Volatile Emissions Response of Soybeans to the Soybean Aphid, Aphis glycines Matsumura (Hemiptera: Aphididae

Directory of Open Access Journals (Sweden)

Lingshuang Cai

2015-05-01

Full Text Available Insects trigger plants to release volatile compounds that mediate the interaction with both pest and beneficial insects. Soybean aphids (Aphis glycines induces soybean (Glycine max leaves to produce volatiles that attract predators of the aphid. In this research, we describe the use of solid-phase microextraction (SPME for extraction of volatiles from A. glycines-infested plant. Objectives were to (1 determine if SPME can be used to collect soybean plant volatiles and to (2 use headspace SPME-GC-MS approach to screen compounds associated with A. glycines-infested soybeans, grown in the laboratory and in the field, to identify previously known and potentially novel chemical markers of infestation. A total of 62 plant volatiles were identified, representing 10 chemical classes. 39 compounds had not been found in previous studies of soybean volatile emissions. 3-hexen-1-ol, dimethyl nonatriene, indole, caryophyllene, benzaldehyde, linalool, methyl salicylate (MeSA, benzene ethanol, and farnesene were considered herbivore-induced plant volatiles (HIPVs. For reproductive field-grown soybeans, three compounds were emitted in greater abundance from leaves infested with A. glycines, cis-3-hexen-1-ol acetate, MeSA and farnesene. In summary, SPME can detect the emission of HIPVs from plants infested with insect herbivores.

Female offspring desertion and male-only care increase with natural and experimental increase in food abundance

OpenAIRE

Eldegard, Katrine; Sonerud, Geir A.

2009-01-01

In species with biparental care, one parent may escape the costs of parental care by deserting and leaving the partner to care for the offspring alone. A number of theoretical papers have suggested a link between uniparental offspring desertion and ecological factors, but empirical evidence is scarce. We investigated the relationship between uniparental desertion and food abundance in a natural population of Tengmalm's owl Aegolius funereus, both by means of a 5-year observational study and a...

Stochastic volatility models and Kelvin waves

Science.gov (United States)

Lipton, Alex; Sepp, Artur

2008-08-01

We use stochastic volatility models to describe the evolution of an asset price, its instantaneous volatility and its realized volatility. In particular, we concentrate on the Stein and Stein model (SSM) (1991) for the stochastic asset volatility and the Heston model (HM) (1993) for the stochastic asset variance. By construction, the volatility is not sign definite in SSM and is non-negative in HM. It is well known that both models produce closed-form expressions for the prices of vanilla option via the Lewis-Lipton formula. However, the numerical pricing of exotic options by means of the finite difference and Monte Carlo methods is much more complex for HM than for SSM. Until now, this complexity was considered to be an acceptable price to pay for ensuring that the asset volatility is non-negative. We argue that having negative stochastic volatility is a psychological rather than financial or mathematical problem, and advocate using SSM rather than HM in most applications. We extend SSM by adding volatility jumps and obtain a closed-form expression for the density of the asset price and its realized volatility. We also show that the current method of choice for solving pricing problems with stochastic volatility (via the affine ansatz for the Fourier-transformed density function) can be traced back to the Kelvin method designed in the 19th century for studying wave motion problems arising in fluid dynamics.

Stochastic volatility models and Kelvin waves

International Nuclear Information System (INIS)

Lipton, Alex; Sepp, Artur

2008-01-01

We use stochastic volatility models to describe the evolution of an asset price, its instantaneous volatility and its realized volatility. In particular, we concentrate on the Stein and Stein model (SSM) (1991) for the stochastic asset volatility and the Heston model (HM) (1993) for the stochastic asset variance. By construction, the volatility is not sign definite in SSM and is non-negative in HM. It is well known that both models produce closed-form expressions for the prices of vanilla option via the Lewis-Lipton formula. However, the numerical pricing of exotic options by means of the finite difference and Monte Carlo methods is much more complex for HM than for SSM. Until now, this complexity was considered to be an acceptable price to pay for ensuring that the asset volatility is non-negative. We argue that having negative stochastic volatility is a psychological rather than financial or mathematical problem, and advocate using SSM rather than HM in most applications. We extend SSM by adding volatility jumps and obtain a closed-form expression for the density of the asset price and its realized volatility. We also show that the current method of choice for solving pricing problems with stochastic volatility (via the affine ansatz for the Fourier-transformed density function) can be traced back to the Kelvin method designed in the 19th century for studying wave motion problems arising in fluid dynamics

Stochastic volatility models and Kelvin waves

Energy Technology Data Exchange (ETDEWEB)

Lipton, Alex [Merrill Lynch, Mlfc Main, 2 King Edward Street, London EC1A 1HQ (United Kingdom); Sepp, Artur [Merrill Lynch, 4 World Financial Center, New York, NY 10080 (United States)], E-mail: Alex_Lipton@ml.com, E-mail: Artur_Sepp@ml.com

2008-08-29

We use stochastic volatility models to describe the evolution of an asset price, its instantaneous volatility and its realized volatility. In particular, we concentrate on the Stein and Stein model (SSM) (1991) for the stochastic asset volatility and the Heston model (HM) (1993) for the stochastic asset variance. By construction, the volatility is not sign definite in SSM and is non-negative in HM. It is well known that both models produce closed-form expressions for the prices of vanilla option via the Lewis-Lipton formula. However, the numerical pricing of exotic options by means of the finite difference and Monte Carlo methods is much more complex for HM than for SSM. Until now, this complexity was considered to be an acceptable price to pay for ensuring that the asset volatility is non-negative. We argue that having negative stochastic volatility is a psychological rather than financial or mathematical problem, and advocate using SSM rather than HM in most applications. We extend SSM by adding volatility jumps and obtain a closed-form expression for the density of the asset price and its realized volatility. We also show that the current method of choice for solving pricing problems with stochastic volatility (via the affine ansatz for the Fourier-transformed density function) can be traced back to the Kelvin method designed in the 19th century for studying wave motion problems arising in fluid dynamics.

Exposure to Anacardiaceae volatile oils and their constituents induces lipid peroxidation within food-borne bacteria cells.

Science.gov (United States)

Montanari, Ricardo M; Barbosa, Luiz C A; Demuner, Antonio J; Silva, Cleber J; Andrade, Nelio J; Ismail, Fyaz M D; Barbosa, Maria C A

2012-08-14

The chemical composition of the volatile oils from five Anacardiaceae species and their activities against Gram positive and negative bacteria were assessed. The peroxidative damage within bacterial cell membranes was determined through the breakdown product malondialdehyde (MDA). The major constituents in Anacardium humile leaves oil were (E)-caryophyllene (31.0%) and α-pinene (22.0%), and in Anacardium occidentale oil they were (E)-caryophyllene (15.4%) and germacrene-D (11.5%). Volatile oil from Astronium fraxinifolium leaves were dominated by (E)-β-ocimene (44.1%) and α-terpinolene (15.2%), whilst the oil from Myracrodruon urundeuva contained an abundance of δ-3-carene (78.8%). However, Schinus terebinthifolius leaves oil collected in March and July presented different chemical compositions. The oils from all species, except the one from A. occidentale, exhibited varying levels of antibacterial activity against Staphylococcus aureus, Bacillus cereus and Escherichia coli. Oil extracted in July from S. terebinthifolius was more active against all bacterial strains than the corresponding oil extracted in March. The high antibacterial activity of the M. urundeuva oil could be ascribed to its high δ-3-carene content. The amounts of MDA generated within bacterial cells indicate that the volatile oils induce lipid peroxidation. The results suggest that one putative mechanism of antibacterial action of these volatile oils is pro-oxidant damage within bacterial cell membrane explaining in part their preservative properties.

Siderophile Volatile Element Partitioning during Core Formation.

Science.gov (United States)

Loroch, D. C.; Hackler, S.; Rohrbach, A.; Klemme, S.

2017-12-01

Since the nineteen sixties it is known, that the Earth's mantle is depleted relative to CI chondrite in numerous elements as a result of accretion and core-mantle differentiation. Additionally, if we take the chondritic composition as the initial solar nebular element abundances, the Earth lacks 85 % of K and up to 98 % of other volatiles. However one potentially very important group of elements has received considerably less attention in this context and these elements are the siderophile but volatile elements (SVEs). SVEs perhaps provide important information regarding the timing of volatile delivery to Earth. Especially for the SVEs the partitioning between metal melt and silicate melt (Dmetal/silicate) at core formation conditions is poorly constrained, never the less they are very important for most of the core formation models. This study is producing new metal-silicate partitioning data for a wide range of SVEs (S, Se, Te, Tl, Ag, As, Au, Cd, Bi, Pb, Sn, Cu, Ge, Zn, In and Ga) with a focus on the P, T and fO2dependencies. The initial hypothesis that we are aiming to test uses the accretion of major portions of volatile elements while the core formation was still active. The key points of this study are: - What are the effects of P, T and fO2 on SVE metal-silicate partioning? - What is the effect of compositional complexity on SVE metal-silicate partioning? - How can SVE's D-values fit into current models of core formation? The partitioning experiments will be performed using a Walker type multi anvil apparatus in a pressure range between 10 and 20 GPa and temperatures of 1700 up to 2100 °C. To determine the Dmetal/silicate values we are using a field emission high-resolution JEOL JXA-8530F EPMA for major elements and a Photon Machines Analyte G2 Excimer laser (193 nm) ablation system coupled to a Thermo Fisher Element 2 single-collector ICP-MS (LA-ICP-MS) for the trace elements. We recently finished the first sets of experiments and can provide the

Review of methods for determination of ammonia volatilization in farmland

Science.gov (United States)

Yang, J.; Jiao, Y.; Yang, W. Z.; Gu, P.; Bai, S. G.; Liu, L. J.

2018-02-01

Ammonia is one of the most abundant alkaline trace gases in the atmosphere, which is one of the important factors affecting atmospheric quality. Excessive application of nitrogen fertilizer is the main source of global ammonia emissions, which not only exacerbate greenhouse gas emissions, but also leads to eutrophication of water bodies. In this paper, the basic principle, the operation process, the advantages and disadvantages, and the previous research results of the method are summarized in detail, including the enclosure method, the venting method, the continuous airflow enclosure method, the wind tunnel method and the micro-meteorological method. So as to provide a theoretical basis for selecting the appropriate method for determination of ammonia volatilization.

The price of fixed income market volatility

CERN Document Server

Mele, Antonio

2015-01-01

Fixed income volatility and equity volatility evolve heterogeneously over time, co-moving disproportionately during periods of global imbalances and each reacting to events of different nature. While the methodology for options-based "model-free" pricing of equity volatility has been known for some time, little is known about analogous methodologies for pricing various fixed income volatilities. This book fills this gap and provides a unified evaluation framework of fixed income volatility while dealing with disparate markets such as interest-rate swaps, government bonds, time-deposits and credit. It develops model-free, forward looking indexes of fixed-income volatility that match different quoting conventions across various markets, and uncovers subtle yet important pitfalls arising from naïve superimpositions of the standard equity volatility methodology when pricing various fixed income volatilities. The ultimate goal of the authors´ efforts is to make interest rate volatility standardization a valuable...

Regulation of hypothalamic-pituitary-interrenal axis function in male smallmouth bass (Micropterus dolomieu) during parental care.

Science.gov (United States)

Jeffrey, J D; Cooke, S J; Gilmour, K M

2014-08-01

Male smallmouth bass (Micropterus dolomieu) provide sole parental care until offspring reach independence, a period of several weeks. During the early parental care period when males are guarding fresh eggs (MG-FE), cortisol responsiveness is attenuated; the response is re-established when males reach the end of the parental care period and are guarding free-swimming fry (MG-FSF). It was hypothesized that attenuation of the cortisol response in male smallmouth bass during early parental care reflected modulation of hypothalamic-pituitary-interrenal (HPI) axis function. Male smallmouth bass were sampled at the beginning (MG-FE) and end of the parental care period (MG-FSF), before and/or 25 min after exposure to a standardized stressor consisting of 3 min of air exposure. Repeated sampling of stressed fish for analysis of plasma cortisol and adrenocorticotropic hormone (ACTH) levels was carried out. Males significantly elevated both plasma cortisol and ACTH levels when guarding free-swimming fry but not during early parental care. Control and stressed fish were terminally sampled for tissue mRNA abundance of preoptic area (POA) and hypothalamic corticotropin-releasing factor (CRF) as well as head kidney melanocortin 2 receptor (MC2R), steroidogenic acute regulatory protein (StAR) and cytochrome P450 side chain cleavage enzyme (P450scc). No significant differences in either hypothalamus CRF or head kidney P450scc mRNA abundance were found across parental care stages or in response to stress. However, POA CRF mRNA abundance and interrenal cell MC2R and StAR mRNA abundances failed to increase in response to stress in MG-FE. Thus, the attenuated cortisol response in males guarding fresh eggs may be explained by hypoactive HPI axis function in response to stress. The present is one of few studies, and the first teleost study, to address the mechanisms underlying resistance to stress during the reproductive/parental care period. Copyright © 2014 Elsevier Inc. All rights

Arp 202: a TDG formed in a parent's extended dark matter halo?

Science.gov (United States)

Scott, T. C.; Lagos, P.; Ramya, S.; Sengupta, C.; Paudel, S.; Sahu, D. K.; Misra, K.; Woo, J.-H.; Sohn, B. W.

2018-03-01

We report on H α + [N II] imaging of the Arp 202 interacting pair and its tidal dwarf galaxy (TDG) candidate as well as a GMOS long slit spectrum from the TDG candidate, observed with the Gemini North telescope. Our H α + [N II] imaging reveals the TDG to have an elongated structure, ˜ 1.9 kpc in length with the two principal star-forming knots at either end. Our observations also show the TDG candidate has a recessional VH α ˜ 3032 km s-1, within 100 km s-1 of the parent pair's mean velocity and an oxygen abundance of 12+log(O/H) = 8.10±0.41. The TDG's oxygen abundance is in good agreement with that of a star-forming region in NGC 2719A, one of the parent galaxies, which has an estimated oxygen abundance of 12+log(O/H) = 8.05 ± 0.41. The TDG's VH α and oxygen abundance confirm previous results validating the candidate as a TDG. The absence of detectable emission from the TDG in Spitzer 3.6 and 4.5 μm images together with the lack of absorption lines and weak continuum in the spectrum is consistent with absence the of an old population (≳0.5 Gyr). The location of the TDG within the interaction debris and the absence of indicators of an old stellar population in the TDG is consistent with a scenario in which the TDG is formed from H I stripped from the parent galaxies and within the extended dark matter halo of one of the parents as proposed by Bournaud et al. and Duc et al.

Volatile accretion history of the Earth.

Science.gov (United States)

Wood, B J; Halliday, A N; Rehkämper, M

2010-10-28

It has long been thought that the Earth had a protracted and complex history of volatile accretion and loss. Albarède paints a different picture, proposing that the Earth first formed as a dry planet which, like the Moon, was devoid of volatile constituents. He suggests that the Earth's complement of volatile elements was only established later, by the addition of a small veneer of volatile-rich material at ∼100 Myr (here and elsewhere, ages are relative to the origin of the Solar System). Here we argue that the Earth's mass balance of moderately volatile elements is inconsistent with Albarède's hypothesis but is well explained by the standard model of accretion from partially volatile-depleted material, accompanied by core formation.

Demonstration of Novel Sampling Techniques for Measurement of Turbine Engine Volatile and Non-Volatile Particulate Matter (PM) Emissions

Science.gov (United States)

2017-03-06

WP-201317) Demonstration of Novel Sampling Techniques for Measurement of Turbine Engine Volatile and Non-volatile Particulate Matter (PM... Engine Volatile and Non-Volatile Particulate Matter (PM) Emissions 6. AUTHOR(S) E. Corporan, M. DeWitt, C. Klingshirn, M.D. Cheng, R. Miake-Lye, J. Peck...the performance and viability of two devices to condition aircraft turbine engine exhaust to allow the accurate measurement of total (volatile and non

Financial market volatility and contagion effect: A copula-multifractal volatility approach

Science.gov (United States)

Chen, Wang; Wei, Yu; Lang, Qiaoqi; Lin, Yu; Liu, Maojuan

2014-03-01

In this paper, we propose a new approach based on the multifractal volatility method (MFV) to study the contagion effect between the U.S. and Chinese stock markets. From recent studies, which reveal that multifractal characteristics exist in both developed and emerging financial markets, according to the econophysics literature we could draw conclusions as follows: Firstly, we estimate volatility using the multifractal volatility method, and find out that the MFV method performs best among other volatility models, such as GARCH-type and realized volatility models. Secondly, we analyze the tail dependence structure between the U.S. and Chinese stock market. The estimated static copula results for the entire period show that the SJC copula performs best, indicating asymmetric characteristics of the tail dependence structure. The estimated dynamic copula results show that the time-varying t copula achieves the best performance, which means the symmetry dynamic t copula is also a good choice, for it is easy to estimate and is able to depict both the upper and lower tail dependence structure. Finally, with the results of the previous two steps, we analyze the contagion effect between the U.S. and Chinese stock markets during the subprime mortgage crisis. The empirical results show that the subprime mortgage crisis started in the U.S. and that its stock market has had an obvious contagion effect on the Chinese stock market. Our empirical results should/might be useful for investors allocating their portfolios.

Genetic variation in jasmonic acid- and spider mite-induced plant volatile emission of cucumber accessions and attraction of the predator Phytoseiulus persimilis.

Science.gov (United States)

Kappers, Iris F; Verstappen, Francel W A; Luckerhoff, Ludo L P; Bouwmeester, Harro J; Dicke, Marcel

2010-05-01

Cucumber plants (Cucumis sativus L.) respond to spider-mite (Tetranychus urticae) damage with the release of specific volatiles that are exploited by predatory mites, the natural enemies of the spider mites, to locate their prey. The production of volatiles also can be induced by exposing plants to the plant hormone jasmonic acid. We analyzed volatile emissions from 15 cucumber accessions upon herbivory by spider mites and upon exposure to jasmonic acid using gas chromatography-mass spectrometry. Upon induction, cucumber plants emitted over 24 different compounds, and the blend of induced volatiles consisted predominantly of terpenoids. The total amount of volatiles was higher in plants treated with jasmonic acid than in those infested with spider mites, with (E)-4,8-dimethyl-1,3,7-nonatriene, (E,E)-alpha-farnesene, and (E)-beta-ocimene as the most abundant compounds in all accessions in both treatments. Significant variation among the accessions was found for the 24 major volatile compounds. The accessions differed strongly in total amount of volatiles emitted, and displayed very different odor profiles. Principal component analysis performed on the relative quantities of particular compounds within the blend revealed clusters of highly correlated volatiles, which is suggestive of common metabolic pathways. A number of cucumber accessions also were tested for their attractiveness to Phytoseiulus persimilis, a specialist predator of spider mites. Differences in the attraction of predatory mites by the various accessions correlated to differences in the individual chemical profiles of these accessions. The presence of genetic variation in induced plant volatile emission in cucumber shows that it is possible to breed for cucumber varieties that are more attractive to predatory mites and other biological control agents.

Volatility and leachability of heavy metals and radionuclides in thermally treated HEPA filter media generated from nuclear facilities.

Science.gov (United States)

Yoon, In-Ho; Choi, Wang-Kyu; Lee, Suk-Chol; Min, Byung-Youn; Yang, Hee-Chul; Lee, Kune-Woo

2012-06-15

The purpose of the present study was to apply thermal treatments to reduce the volume of HEPA filter media and to investigate the volatility and leachability of heavy metals and radionuclides during thermal treatment. HEPA filter media were transformed to glassy bulk material by thermal treatment at 900°C for 2h. The most abundant heavy metal in the HEPA filter media was Zn, followed by Sr, Pb and Cr, and the main radionuclide was Cs-137. The volatility tests showed that the heavy metals and radionuclides in radioactive HEPA filter media were not volatilized during the thermal treatment. PCT tests indicated that the leachability of heavy metals and radionuclides was relatively low compared to those of other glasses. XRD results showed that Zn and Cs reacted with HEPA filter media and were transformed into crystalline willemite (ZnO·SiO(2)) and pollucite (Cs(2)OAl(2)O(3)4SiO(2)), which are not volatile or leachable. The proposed technique for the volume reduction and transformation of radioactive HEPA filter media into glassy bulk material is a simple and energy efficient procedure without additives that can be performed at relatively low temperature compared with conventional vitrification process. Copyright © 2012 Elsevier B.V. All rights reserved.

Dynamic Estimation of Volatility Risk Premia and Investor Risk Aversion from Option-Implied and Realized Volatilities

DEFF Research Database (Denmark)

Bollerslev, Tim; Gibson, Michael; Zhou, Hao

experiment confirms that the procedure works well in practice. Implementing the procedure with actual S&P500 option-implied volatilities and high-frequency five-minute-based realized volatilities indicates significant temporal dependencies in the estimated stochastic volatility risk premium, which we in turn...

Parallel Prediction of Stock Volatility

Directory of Open Access Journals (Sweden)

Priscilla Jenq

2017-10-01

Full Text Available Volatility is a measurement of the risk of financial products. A stock will hit new highs and lows over time and if these highs and lows fluctuate wildly, then it is considered a high volatile stock. Such a stock is considered riskier than a stock whose volatility is low. Although highly volatile stocks are riskier, the returns that they generate for investors can be quite high. Of course, with a riskier stock also comes the chance of losing money and yielding negative returns. In this project, we will use historic stock data to help us forecast volatility. Since the financial industry usually uses S&P 500 as the indicator of the market, we will use S&P 500 as a benchmark to compute the risk. We will also use artificial neural networks as a tool to predict volatilities for a specific time frame that will be set when we configure this neural network. There have been reports that neural networks with different numbers of layers and different numbers of hidden nodes may generate varying results. In fact, we may be able to find the best configuration of a neural network to compute volatilities. We will implement this system using the parallel approach. The system can be used as a tool for investors to allocating and hedging assets.

Volatile communication in plant-aphid interactions.

Science.gov (United States)

de Vos, Martin; Jander, Georg

2010-08-01

Volatile communication plays an important role in mediating the interactions between plants, aphids, and other organisms in the environment. In response to aphid infestation, many plants initiate indirect defenses through the release of volatiles that attract ladybugs, parasitoid wasps, and other aphid-consuming predators. Aphid-induced volatile release in the model plant Arabidopsis thaliana requires the jasmonate signaling pathway. Volatile release is also induced by infection with aphid-transmitted viruses. Consistent with mathematical models of optimal transmission, viruses that are acquired rapidly by aphids induce volatile release to attract migratory aphids, but discourage long-term aphid feeding. Although the ecology of these interactions is well-studied, further research is needed to identify the molecular basis of aphid-induced and virus-induced changes in plant volatile release. Copyright 2010 Elsevier Ltd. All rights reserved.

Essays on nonparametric econometrics of stochastic volatility

NARCIS (Netherlands)

Zu, Y.

2012-01-01

Volatility is a concept that describes the variation of financial returns. Measuring and modelling volatility dynamics is an important aspect of financial econometrics. This thesis is concerned with nonparametric approaches to volatility measurement and volatility model validation.

The exploitation of volatile oil

Institute of Scientific and Technical Information of China (English)

MENG Teng; ZHANG Da; TENG Xiangjin; LINing; HAO Zaibin

2007-01-01

Rose is a kind of favorite ornamental plant. This article briefly introduced the cultivation and the use of rose around the world both in ancient time and nowadays. Today, volatile oil becomes the mainstream of the rose industry. People pay attention to the effect of volatile oil; meanwhile, they speed up their research on extracting volatile oil and the ingredients.

Understanding Financial Market Volatility

NARCIS (Netherlands)

A. Opschoor (Anne)

2014-01-01

markdownabstract__Abstract__ Volatility has been one of the most active and successful areas of research in time series econometrics and economic forecasting in recent decades. Loosely speaking, volatility is defined as the average magnitude of fluctuations observed in some phenomenon over

Oil Volatility Risk and Expected Stock Returns

DEFF Research Database (Denmark)

Christoffersen, Peter; Pan, Xuhui (Nick)

After the financialization of commodity futures markets in 2004-05 oil volatility has become a strong predictor of returns and volatility of the overall stock market. Furthermore, stocks' exposure to oil volatility risk now drives the cross-section of expected returns. The difference in average...... return between the quintile of stocks with low exposure and high exposure to oil volatility is significant at 0.66% per month, and oil volatility risk carries a significant risk premium of -0.60% per month. In the post-financialization period, oil volatility risk is strongly related with various measures...

A temporal record of pre-eruptive magmatic volatile contents at Campi Flegrei: Insights from texturally-constrained apatite analyses

Science.gov (United States)

Stock, Michael J.; Isaia, Roberto; Humphreys, Madeleine C. S.; Smith, Victoria C.; Pyle, David M.

2016-04-01

Apatite is capable of incorporating all major magmatic volatile species (H2O, CO2, S, Cl and F) into its crystal structure. Analysis of apatite volatile contents can be related to parental magma compositions through the application of pressure and temperature-dependent exchange reactions (Piccoli and Candela, 1994). Once included within phenocrysts, apatite inclusions are isolated from the melt and preserve a temporal record of magmatic volatile contents in the build-up to eruption. In this work, we measured the volatile compositions of apatite inclusions, apatite microphenocrysts and pyroxene-hosted melt inclusions from the Astroni 1 eruption of Campi Flegrei, Italy (Stock et al. 2016). These data are coupled with magmatic differentiation models (Gualda et al., 2012), experimental volatile solubility data (Webster et al., 2014) and thermodynamic models of apatite compositional variations (Piccoli and Candela, 1994) to decipher pre-eruptive magmatic processes. We find that apatite halogen/OH ratios decreased through magmatic differentiation, while melt inclusion F and Cl concentrations increased. Melt inclusion H2O contents are constant at ~2.5 wt%. These data are best explained by volatile-undersaturated differentiation over most of the crystallisation history of the Astroni 1 melt, with melt inclusion H2O contents reset at shallow levels during ascent. Given the high diffusivity of volatiles in apatite (Brenan, 1993), the preservation of volatile-undersaturated melt compositions in microphenocrysts suggests that saturation was only achieved 10 - 103 days before eruption. We suggest that late-stage transition into a volatile-saturated state caused an increase in magma chamber overpressure, which ultimately triggered the Astroni 1 eruption. This has major implications for monitoring of Campi Flegrei and other similar volcanic systems. Piccoli and Candela, 1994. Am. J. of Sc., 294, 92-135. Stock et al., 2016, Nat. Geosci. Gualda et al., 2012. J. Pet., 53, 875

Core-Mantle Partitioning of Volatile Elements and the Origin of Volatile Elements in Earth and Moon

Science.gov (United States)

Righter, K.; Pando, K.; Danielson, L.; Nickodem, K.

2014-01-01

Depletions of siderophile elements in mantles have placed constraints on the conditions on core segregation and differentiation in bodies such as Earth, Earth's Moon, Mars, and asteroid 4 Vesta. Among the siderophile elements there are a sub-set that are also volatile (volatile siderophile elements or VSE; Ga, Ge, In, As, Sb, Sn, Bi, Zn, Cu, Cd), and thus can help to constrain the origin of volatile elements in these bodies, and in particular the Earth and Moon. One of the fundamental observations of the geochemistry of the Moon is the overall depletion of volatile elements relative to the Earth, but a satisfactory explanation has remained elusive. Hypotheses for Earth include addition during accretion and core formation and mobilized into the metallic core, multiple stage origin, or addition after the core formed. Any explanation for volatile elements in the Earth's mantle must also be linked to an explanation of these elements in the lunar mantle. New metal-silicate partitioning data will be applied to the origin of volatile elements in both the Earth and Moon, and will evaluate theories for exogenous versus endogenous origin of volatile elements.

Supercritical fluid extraction of volatile and non-volatile compounds from Schinus molle L.

Directory of Open Access Journals (Sweden)

M. S. T. Barroso

2011-06-01

Full Text Available Schinus molle L., also known as pepper tree, has been reported to have antimicrobial, antifungal, anti-inflammatory, antispasmodic, antipyretic, antitumoural and cicatrizing properties. This work studies supercritical fluid extraction (SFE to obtain volatile and non-volatile compounds from the aerial parts of Schinus molle L. and the influence of the process on the composition of the extracts. Experiments were performed in a pilot-scale extractor with a capacity of 1 L at pressures of 9, 10, 12, 15 and 20 MPa at 323.15 K. The volatile compounds were obtained by CO2 supercritical extraction with moderate pressure (9 MPa, whereas the non-volatile compounds were extracted at higher pressure (12 to 20 MPa. The analysis of the essential oil was carried out by GC-MS and the main compounds identified were sabinene, limonene, D-germacrene, bicyclogermacrene, and spathulenol. For the non-volatile extracts, the total phenolic content was determined by the Folin-Ciocalteau method. Moreover, one of the goals of this study was to compare the experimental data with the simulated yields predicted by a mathematical model based on mass transfer. The model used requires three adjustable parameters to predict the experimental extraction yield curves.

Field comparison of an eddy accumulation and an aerodynamic-gradient system for measuring pesticide volatilization fluxes

Science.gov (United States)

Majewski, M.; Desjardina, R.; Rochette, P.; Pattey, E.; Selber, J.; Glotfelty, D.

1993-01-01

The field experiment reported here applied the relaxed eddy accumulation (REA) technique to the measurement of triallate (TA) and trifluralin (TF) volatilization from fallow soil. A critical analysis of the REA system used in this experiment is done, and the fluxes are compared to those obtained by the aerodynamic-gradient (AG) technique. The measured cumulative volatilization losses, corrected for the effective upwind source area (footprint), for the AG system were higher than with the REA system. The differences between the methods over the first 5 days of the experiment were 27 and 13% for TA and TF, respectively. A mass balance based on the amount of parent compounds volatilized from soil during the first 5 days of the experiment showed a 110 and 70% and a 79 and 61% accountability for triallate and trifluralin by the AG and REA methods, respectively. These results also show that the non-footprint-corrected AG flux values underestimated the volatilization flux by approximately 16%. The footprint correction model used in this experiment does not presently have the capability of accounting for changes in atmospheric stability. However, these values still provide an indication of the most likely upwind area affecting the evaporative flux estimations. The soil half-lives for triallate and trifluralin were 9.8 and 7.0 days, respectively. ?? 1992 American Chemical Society.

Morphology and volatile compounds of metathoracic scent gland in Tessaratoma papillosa (Drury) (Hemiptera: Tessaratomidae).

Science.gov (United States)

Zhao, D; Gao, J; Wang, Y; Jiang, J; Li, R

2012-08-01

Tessaratoma papillosa (Drury) (Hemiptera: Tessaratomidae) is a serious insect pest of litchi and longan in South China. When disturbed, this insect could release large quantities of disagreeable odorous volatiles from its scent gland. Knowledge on the scent gland and its secretion is crucial for developing the semiochemical methods to manage this pest. Morphology and ultrastructure of the metathoracic scent glands (MTGs) were studied under stereo and scanning electron microscopy, and the volatile compounds of MTGs from both male and female T. papillosa were analyzed with coupled gas chromatography-mass spectrometry (GC-MS). The MTG complex is located between the metathorax and the first abdominal segment at the ventral surface of the insect, which has a well-developed single double valve cystic-shaped orange median reservoir, paired colorless lateral glands in both sides, and a long and wavy tubular accessory gland that inlays tightly into the ventral edge around the median reservoir. The MTG opens to the body surface through paired ostioles located between the meso- and metacoxae of the evaporatorium with mushroom bodies. The GC-MS analyses showed that female and male adults have nine major volatile components in common. Tridecane is the most abundant in both females and males, reaching up to 47.1% and 51.8% of relative amount, respectively. The minor component is benzophenone with only 0.28% and 0.14%. Furthermore, undecane, tetradecane, 3-methyl-tridecane, and cyclopentadecane were found only in males. The possible function of volatile compounds of MTG contents in T. papillosa is addressed.

Long Memory in Stock Market Volatility and the Volatility-in-Mean Effect: The FIEGARCH-M Model

DEFF Research Database (Denmark)

Christensen, Bent Jesper; Nielsen, Morten Ørregaard; Zhu, Jie

We extend the fractionally integrated exponential GARCH (FIEGARCH) model for daily stock return data with long memory in return volatility of Bollerslev and Mikkelsen (1996) by introducing a possible volatility-in-mean effect. To avoid that the long memory property of volatility carries over to r...

Can Halogen Enrichment in Reduced Enstatite Chondrites Provide Clues to Volatile Accretion in the Early Earth?

Science.gov (United States)

Clay, P. L.; Burgess, R.; Busemann, H.; Ruzié, L.; Joachim, B.; Ballentine, C.

2013-12-01

Understanding how the Earth obtained and ultimately retained its volatiles is important for our overall understanding of large scale planetary evolution. Numerous models exist for the heterogeneous accretion of volatiles to early Earth, but accounting for all elements through accretion of typical planetary building blocks (e.g., CI chondrites) is difficult. Proto-planetary collisions resulting in the accretion of volatile-poor material under reducing conditions followed by accretion of volatile-rich material under oxidizing conditions has been suggested in such models [e.g., 1]. The heavy halogens (Cl, Br and I), a group of moderately volatile elements, are excellent tracers of planetary processing due to their low abundance and incompatible nature. Therefore characterizing halogen abundance and distribution in materials that accreted to form the planets, e.g., primitive meteorites, is crucial. One group of primitive meteorites, the enstatite chondrites (EC's), are amongst the most reduced materials in the solar system as evidenced by their unique mineral assemblage. Yet despite forming under ultra-reducing conditions, they are enriched in the moderately volatile elements, such as the halogens. The ECs are of particular interest owing to their oxygen isotopic composition which plots along the terrestrial fractionation line, linking them isotopically to the Earth-Moon system. These samples can thus potentially provide clues on the accretion of moderately volatile element rich material under reducing conditions, such as it may have existed during the early stages of Earth's accretion. Chlorine, Br and I concentrations in ECs were determined through step-heating small neutron-irradiated samples (0.3 to 3.3 mg) and measured by mass spectrometry using the noble gas proxy isotopes 38ArCl/Cl, 80KrBr/Br and 128XeI/I. The EH chondrites are consistently enriched in the heavy halogens (up to 330 ppm Cl, 2290 ppb Br and 180 ppb I), compared to other ordinary and carbonaceous

Asymmetric Realized Volatility Risk

NARCIS (Netherlands)

D.E. Allen (David); M.J. McAleer (Michael); M. Scharth (Marcel)

2014-01-01

markdownabstract__Abstract__ In this paper we document that realized variation measures constructed from high-frequency returns reveal a large degree of volatility risk in stock and index returns, where we characterize volatility risk by the extent to which forecasting errors in realized

On krypton isotopic abundances in the sun and in the solar wind

Science.gov (United States)

Marti, K.

1980-01-01

The Kr isotopic systematics in the meteorite Pesyanoe which is known to contain solar-type gases, are reported. Discrepancies in the isotopic data of fractions released at stepwise increasing temperatures cannot be reconciled with spallation Kr components, although spallation effects are significant. Fractionation mechanisms on the parent body and in the solar wind source region are considered and the implications for solar abundances discussed.

Nonparametric methods for volatility density estimation

NARCIS (Netherlands)

Es, van Bert; Spreij, P.J.C.; Zanten, van J.H.

2009-01-01

Stochastic volatility modelling of financial processes has become increasingly popular. The proposed models usually contain a stationary volatility process. We will motivate and review several nonparametric methods for estimation of the density of the volatility process. Both models based on

Uncertainty of Volatility Estimates from Heston Greeks

Directory of Open Access Journals (Sweden)

Oliver Pfante

2018-01-01

Full Text Available Volatility is a widely recognized measure of market risk. As volatility is not observed it has to be estimated from market prices, i.e., as the implied volatility from option prices. The volatility index VIX making volatility a tradeable asset in its own right is computed from near- and next-term put and call options on the S&P 500 with more than 23 days and less than 37 days to expiration and non-vanishing bid. In the present paper we quantify the information content of the constituents of the VIX about the volatility of the S&P 500 in terms of the Fisher information matrix. Assuming that observed option prices are centered on the theoretical price provided by Heston's model perturbed by additive Gaussian noise we relate their Fisher information matrix to the Greeks in the Heston model. We find that the prices of options contained in the VIX basket allow for reliable estimates of the volatility of the S&P 500 with negligible uncertainty as long as volatility is large enough. Interestingly, if volatility drops below a critical value of roughly 3%, inferences from option prices become imprecise because Vega, the derivative of a European option w.r.t. volatility, and thereby the Fisher information nearly vanishes.

Volatile Organic Compounds Emissions from Luculia pinceana Flower and Its Changes at Different Stages of Flower Development

Directory of Open Access Journals (Sweden)

Yuying Li

2016-04-01

Full Text Available Luculia plants are famed ornamental plants with sweetly fragrant flowers, of which L. pinceana Hooker, found primarily in Yunnan Province, China, has the widest distribution. Solid phase microextraction-gas chromatography-mass spectrometry (SPME-GC-MS was employed to identify the volatile organic compounds (VOCs emitted from different flower development stages of L. pinceana for the evaluation of floral volatile polymorphism. Peak areas were normalized as percentages and used to determine the relative amounts of the volatiles. The results showed that a total of 39 compounds were identified at four different stages of L. pinceana flower development, including 26 at the bud stage, 26 at the initial-flowering stage, 32 at the full-flowering stage, and 32 at the end-flowering stage. The most abundant compound was paeonol (51%–83% followed by (E,E-α-farnesene, cyclosativene, and δ-cadinene. All these volatile compounds create the unique fragrance of L. pinceana flower. Floral scent emission offered tendency of ascending first and descending in succession, meeting its peak level at the initial-flowering stage. The richest diversity of floral volatile was detected at the third and later periods of flower development. Principal component analysis (PCA indicated that the composition and its relative content of floral scent differed throughout the whole flower development. The result has important implications for future floral fragrance breeding of Luculia. L. pinceana would be adequate for a beneficial houseplant and has a promising prospect for development as essential oil besides for a fragrant ornamental owing to the main compounds of floral scent with many medicinal properties.

Fluctuation behaviors of financial return volatility duration

Science.gov (United States)

Niu, Hongli; Wang, Jun; Lu, Yunfan

2016-04-01

It is of significantly crucial to understand the return volatility of financial markets because it helps to quantify the investment risk, optimize the portfolio, and provide a key input of option pricing models. The characteristics of isolated high volatility events above certain threshold in price fluctuations and the distributions of return intervals between these events arouse great interest in financial research. In the present work, we introduce a new concept of daily return volatility duration, which is defined as the shortest passage time when the future volatility intensity is above or below the current volatility intensity (without predefining a threshold). The statistical properties of the daily return volatility durations for seven representative stock indices from the world financial markets are investigated. Some useful and interesting empirical results of these volatility duration series about the probability distributions, memory effects and multifractal properties are obtained. These results also show that the proposed stock volatility series analysis is a meaningful and beneficial trial.

Ambient Volatility of Triethyl Phosphate

Science.gov (United States)

2017-08-01

of materials is predictable using Raoult’s law. This report details the measurement of the effect of water vapor partial pressure on the volatility...empirical correlation taking into account nonideal behavior was developed to enable estimation of TEPO volatility at any combination of ambient...of the second component is expected to be one-half as much as in the absence of water vapor. Similarly, the measured volatility of the second

A global perspective on aerosol from low-volatility organic compounds

Directory of Open Access Journals (Sweden)

H. O. T. Pye

2010-05-01

Full Text Available Global production of organic aerosol from primary emissions of semivolatile (SVOCs and intermediate (IVOCs volatility organic compounds is estimated using the global chemical transport model, GEOS-Chem. SVOC oxidation is predicted to be a larger global source of net aerosol production than oxidation of traditional parent hydrocarbons (terpenes, isoprene, and aromatics. Using a prescribed rate constant and reduction in volatility for atmospheric oxidation, the yield of aerosol from SVOCs is predicted to be about 75% on a global, annually-averaged basis. For IVOCs, the use of a naphthalene-like surrogate with different high-NO_x and low-NO_x parameterizations produces a global aerosol yield of about 30%, or roughly 5 Tg/yr of aerosol. Estimates of the total global organic aerosol source presented here range between 60 and 100 Tg/yr. This range reflects uncertainty in the parameters for SVOC volatility, SVOC oxidation, SVOC emissions, and IVOC emissions, as well as wet deposition. The highest estimates result if SVOC emissions are significantly underestimated (by more than a factor of 2 or if wet deposition of the gas-phase semivolatile species is less effective than previous estimates. A significant increase in SVOC emissions, a reduction of the volatility of the SVOC emissions, or an increase in the enthalpy of vaporization of the organic aerosol all lead to an appreciable reduction of prediction/measurement discrepancy. In addition, if current primary organic aerosol (POA inventories capture only about one-half of the SVOC emission and the Henrys Law coefficient for oxidized semivolatiles is on the order of 10³ M/atm, a global estimate of OA production is not inconsistent with the top-down estimate of 140 Tg/yr by (Goldstein and Galbally, 2007. Additional information is needed to constrain the emissions and treatment of SVOCs and IVOCs, which have traditionally not been included in models.

Volatility persistence in crude oil markets

International Nuclear Information System (INIS)

Charles, Amélie; Darné, Olivier

2014-01-01

Financial market participants and policy-makers can benefit from a better understanding of how shocks can affect volatility over time. This study assesses the impact of structural changes and outliers on volatility persistence of three crude oil markets – Brent, West Texas Intermediate (WTI) and Organization of Petroleum Exporting Countries (OPEC) – between January 2, 1985 and June 17, 2011. We identify outliers using a new semi-parametric test based on conditional heteroscedasticity models. These large shocks can be associated with particular event patterns, such as the invasion of Kuwait by Iraq, the Operation Desert Storm, the Operation Desert Fox, and the Global Financial Crisis as well as OPEC announcements on production reduction or US announcements on crude inventories. We show that outliers can bias (i) the estimates of the parameters of the equation governing volatility dynamics; (ii) the regularity and non-negativity conditions of GARCH-type models (GARCH, IGARCH, FIGARCH and HYGARCH); and (iii) the detection of structural breaks in volatility, and thus the estimation of the persistence of the volatility. Therefore, taking into account the outliers on the volatility modelling process may improve the understanding of volatility in crude oil markets. - Highlights: • We study the impact of outliers on volatility persistence of crude oil markets. • We identify outliers and patches of outliers due to specific events. • We show that outliers can bias (i) the estimates of the parameters of GARCH models, (ii) the regularity and non-negativity conditions of GARCH-type models, (iii) the detection of structural breaks in volatility of crude oil markets

Improving Garch Volatility Forecasts

NARCIS (Netherlands)

Klaassen, F.J.G.M.

1998-01-01

Many researchers use GARCH models to generate volatility forecasts. We show, however, that such forecasts are too variable. To correct for this, we extend the GARCH model by distinguishing two regimes with different volatility levels. GARCH effects are allowed within each regime, so that our model

The effect of volatility on percutaneous absorption.

Science.gov (United States)

Rouse, Nicole C; Maibach, Howard I

2016-01-01

Topically applied chemicals may volatilize, or evaporate, from skin leaving behind a chemical residue with new percutaneous absorptive capabilities. Understanding volatilization of topical medications, such as sunscreens, fragrances, insect repellants, cosmetics and other commonly applied topicals may have implications for their safety and efficacy. A systematic review of English language articles from 1979 to 2014 was performed using key search terms. Articles were evaluated to assess the relationship between volatility and percutaneous absorption. A total of 12 articles were selected and reviewed. Key findings were that absorption is enhanced when coupled with a volatile substance, occlusion prevents evaporation and increases absorption, high ventilation increases volatilization and reduces absorption, and pH of skin has an affect on a chemical's volatility. The articles also brought to light that different methods may have an affect on volatility: different body regions; in vivo vs. in vitro; human vs. Data suggest that volatility is crucial for determining safety and efficacy of cutaneous exposures and therapies. Few articles have been documented reporting evaporation in the context of percutaneous absorption, and of those published, great variability exists in methods. Further investigation of volatility is needed to properly evaluate its role in percutaneous absorption.

Volatile compounds analysis of Dacia sausage, a traditional Romanian dry cured sausage

Directory of Open Access Journals (Sweden)

Ana Maria SIMION CIUCIU

2014-12-01

Full Text Available Three batches of Dacia sausage were produced as follows: one without starter culture and two with a mix of starter cultures. Volatiles were extracted by a purgeand- trap method and analyzed by gas chromatographic/mass spectrometry. Approximately 43 compounds were identified. The substances identified belong to: aldehydes, alcohols, ketones, hydrocarbons, esters, acids, furans. Results indicated that the most abundant class of chemical substances in flavor at the end of the ripening process was esters, followed by aldehydes, hydrocarbures and terpenes. This could only indicate the high microbial esterification activity that took place in the batches. It was possible to differentiate between the three sausages applying a discriminant analysis.

Interior Volatile Reservoirs in Mercury

Science.gov (United States)

Anzures, B. A.; Parman, S. W.; Milliken, R. E.; Head, J. W.

2018-05-01

More measurements of 1) surface volatiles, and 2) pyroclastic deposits paired with experimental volatile analyses in silicate minerals can constrain conditions of melting and subsequent eruption on Mercury.

Chemical Composition of the Semi-Volatile Grains of Comet 67P/Churyumov-Gerasimenko

Science.gov (United States)

Wurz, P.; Altwegg, K.; Balsiger, H. R.; Berthelier, J. J.; De Keyser, J.; Fiethe, B.; Fuselier, S. A.; Gasc, S.; Gombosi, T. I.; Korth, A.; Mall, U.; Reme, H.; Rubin, M.; Tzou, C. Y.

2017-12-01

Rosetta was in orbit of comet 67P/Churyumov-Gerasimenko from August 2014 to September 2016. On board is the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) experiment that has been continuously collecting data on the chemical composition and activity of the coma from 3.5 AU to pericentre at 1.24 AU and out again to 3.5 AU. ROSINA consists of two mass spectrometers, the Double Focusing Mass Spectrometer (DFMS) and the Reflectron-type Time-Of-Flight (RTOF), as well as the COmet Pressure Sensor (COPS). ROSINA recorded the neutral gas and thermal plasma in the comet's coma. The two mass spectrometers have high dynamic ranges and complement each other with high mass resolution, and high time resolution and large mass range. COPS measures total gas densities, bulk velocities, and gas temperatures. Occasionally, a dust grain of cometary origin enters the ion source of a ROSINA instrument where the volatile part evaporates since these ion sources are hot. The release of volatiles from cometary dust grains was observed with all three ROSINA instruments on several occasions. Because the volatile content of such a dust grain is completely evaporated after a few seconds, the RTOF instrument is best suited for the investigation of its chemical composition since complete mass spectra are recorded during this time. During the mission 9 dust grains were observed with RTOF during the October 2014 to July 2016 time period. It is estimated that these grains contain about 10-15 g of volatiles. The mass spectra were interpreted with a set of 75 molecules, with the major groups of chemical species being hydrocarbons, oxygenated hydrocarbons, nitrogen-bearing molecules, sulphur-bearing molecules, halogenated molecules and others. About 70% of these grains are depleted in water compared to the comet coma, thus, can be considered as semi-volatile dust grains, and the other about 30% are water grains. The chemical composition varies considerably from grain to grain

Non-volatile memories

CERN Document Server

Lacaze, Pierre-Camille

2014-01-01

Written for scientists, researchers, and engineers, Non-volatile Memories describes the recent research and implementations in relation to the design of a new generation of non-volatile electronic memories. The objective is to replace existing memories (DRAM, SRAM, EEPROM, Flash, etc.) with a universal memory model likely to reach better performances than the current types of memory: extremely high commutation speeds, high implantation densities and retention time of information of about ten years.

Volcanic fluxes of volatiles. Preliminary estimates based on rare gas and major volatile calibration

International Nuclear Information System (INIS)

Marty, B.

1992-01-01

New estimates for volatile fluxes into the atmosphere and hydrosphere through volcanism have been computed using the measured fluxes of 3 He in oceans and SO 2 in the atmosphere, and the ratios between the volatiles in Mid-Ocean Ridge basalts and in high temperature volcanic gases. These estimates have been checked using independent estimates of the volcanic fluxes. This method provides a reliable means of tracing volatile fluxes, although its precision is restricted by the limited amount of data currently available. (author). 19 refs, 1 tab

Differences in volatile profiles of Cabernet Sauvignon grapes grown in two distinct regions of China and their responses to weather conditions.

Science.gov (United States)

Xu, Xiao-Qing; Liu, Bin; Zhu, Bao-Qing; Lan, Yi-Bin; Gao, Yuan; Wang, Dong; Reeves, Malcolm J; Duan, Chang-Qing

2015-04-01

Volatile compounds are considered important for plants to communicate with each other and interact with their environments. Most wine-producing regions in China feature a continental monsoon climate with hot-wet summers and dry-cold winters, giving grapes markedly different growing environments compared to the Mediterranean or oceanic climates described in previous reports. This study focused on comparing the volatile profiles of Vitis vinifera L. cv. Cabernet Sauvignon berries from two regions with distinct climate characteristics: Changli has a warm and semi-humid summer, and Gaotai has a cool-arid summer and a cold winter. The relationship between meteorological metrics and the concentrations of grape volatiles were also examined. In harvested grapes, benzyl alcohol, phenylethyl alcohol, 1-hexanol and 1-octen-3-ol were more abundant in the Changli berries, while hexanal, heptanal, 2-methoxy-3-isobutylpyrazine, and (E)-β-damascenone presented higher levels in the Gaotai berries. The fluctuation in the accumulation of volatile compounds observed during berry development was closely correlated with variations in short-term weather (weather in a week), especially rainfall. The concentration of some volatiles, notably aliphatic aldehydes, was significantly related to diurnal temperature differences. The variability during berry development of concentrations for compounds such as C6 volatile compounds, 2-methoxy-3-isobutylpyrazine and (E)-β-damascenone strongly depended upon weather conditions. This work expands our knowledge about the influence of continental monsoon climates on volatile compounds in developing grape berries. It will also improve the comprehension of the plant response to their surrounding environments through the accumulation of volatiles. The results will help growers to alter viticultural practices according to local conditions to improve the aromatic quality of grapes. Copyright © 2015 Elsevier Masson SAS. All rights reserved.

[Chemical components of Vetiveria zizanioides volatiles].

Science.gov (United States)

Huang, Jinghua; Li, Huashou; Yang, Jun; Chen, Yufen; Liu, Yinghu; Li, Ning; Nie, Chengrong

2004-01-01

The chemical components of the volatiles from Vetiveria zizanioides were analyzed by SPME and GC-MS. In the roots, the main component was valencene (30.36%), while in the shoots and leaves, they were 9-octadecenamide (33.50%), 2,6,10,15,19,23-hexamethyl-2,6,10,14,18,22-tetracosahexaene (27.46%), and 1,2-benzendicarboxylic acid, diisooctyl ester(18.29%). The results showed that there were many terpenoids in the volatils. In shoot volatiles, there existed 3 monoterpenes, 2 sequiterpenes and 1 triterpene. Most of the volatiles in roots were sesquiterpenes.

Volatile Compound Profiling by HS-SPME/GC-MS-FID of a Core Olive Cultivar Collection as a Tool for Aroma Improvement of Virgin Olive Oil

Directory of Open Access Journals (Sweden)

Lourdes García-Vico

2017-01-01

Full Text Available Virgin olive oil (VOO is the only food product requiring official sensory analysis to be classified in commercial categories, in which the evaluation of the aroma plays a very important role. The selection of parents, with the aim of obtaining new cultivars with improved oil aroma, is of paramount importance in olive breeding programs. We have assessed the volatile fraction by headspace-solid-phase microextraction/gas chromatography-mass spectrometry-flame ionization detection (HS-SPME/GC-MS-FID and the deduced aroma properties of VOO from a core set of olive cultivars (Core-36 which possesses most of the genetic diversity found in the World Olive Germplasm Collection (IFAPA Alameda del Obispo located in Cordoba, Spain. The VOO volatile fractions of Core-36 cultivars display a high level of variability. It is mostly made of compounds produced from polyunsaturated fatty acids through the lipoxygenase pathway, which confirms to be a general characteristic of the olive species (Olea europaea L.. The main group of volatile compounds in the oils was six straight-chain carbon compounds derived from linolenic acid, some of them being the main contributors to the aroma of the olive oils according to their odor activity values (OAV. The high level of variability found for the volatile fraction of the oils from Core-36 and, therefore, for the aroma odor notes, suggest that this core set may be a very useful tool for the choice of optimal parents in olive breeding programs in order to raise new cultivars with improved VOO aroma.

Volatile Compound Profiling by HS-SPME/GC-MS-FID of a Core Olive Cultivar Collection as a Tool for Aroma Improvement of Virgin Olive Oil.

Science.gov (United States)

García-Vico, Lourdes; Belaj, Angjelina; Sánchez-Ortiz, Araceli; Martínez-Rivas, José M; Pérez, Ana G; Sanz, Carlos

2017-01-14

Virgin olive oil (VOO) is the only food product requiring official sensory analysis to be classified in commercial categories, in which the evaluation of the aroma plays a very important role. The selection of parents, with the aim of obtaining new cultivars with improved oil aroma, is of paramount importance in olive breeding programs. We have assessed the volatile fraction by headspace-solid-phase microextraction/gas chromatography-mass spectrometry-flame ionization detection (HS-SPME/GC-MS-FID) and the deduced aroma properties of VOO from a core set of olive cultivars (Core-36) which possesses most of the genetic diversity found in the World Olive Germplasm Collection (IFAPA Alameda del Obispo) located in Cordoba, Spain. The VOO volatile fractions of Core-36 cultivars display a high level of variability. It is mostly made of compounds produced from polyunsaturated fatty acids through the lipoxygenase pathway, which confirms to be a general characteristic of the olive species ( Olea europaea L.). The main group of volatile compounds in the oils was six straight-chain carbon compounds derived from linolenic acid, some of them being the main contributors to the aroma of the olive oils according to their odor activity values (OAV). The high level of variability found for the volatile fraction of the oils from Core-36 and, therefore, for the aroma odor notes, suggest that this core set may be a very useful tool for the choice of optimal parents in olive breeding programs in order to raise new cultivars with improved VOO aroma.

Characterisation of the volatile profile of coconut water from five varieties using an optimised HS-SPME-GC analysis.

Science.gov (United States)

Prades, Alexia; Assa, Rebecca Rachel Ablan; Dornier, Manuel; Pain, Jean-Pierre; Boulanger, Renaud

2012-09-01

Coconut (Cocos nucifera L.) water is a refreshing tropical drink whose international market has recently been growing. However, little is yet known about its physicochemical composition, particularly its aroma. This study set out to characterise the volatile profile of water from five coconut varieties. Aroma compounds were characterised by headspace solid phase microextraction gas chromatography (HS-SPME-GC) analysis. An experimental design was established to optimise SPME conditions, leading to an equilibration time of 10 min followed by an extraction time of 60 min at 50 °C. Accordingly, immature coconut water from WAT (West African Tall), PB121 (MYD × WAT Hybrid), MYD (Malayan Yellow Dwarf), EGD (Equatorial Guinea Green Dwarf) and THD (Thailand Aromatic Green Dwarf) palms was analysed and described. Ketones were mainly present in the Tall and Hybrid varieties, whereas aldehydes were most abundant in the Dwarf palms. Tall coconut water was characterised by a high lactone content. THD exhibited a high ethyl octanoate level. The cluster analysis of the volatile fraction from the five coconut cultivars was found to be related to their genetic classification. The volatile compounds of immature coconut water from five varieties were characterised for the first time. Volatile profile analysis could be a useful tool for the selection of Dwarf coconut varieties, which are mainly consumed as a beverage. Copyright © 2012 Society of Chemical Industry.

Volatile flavours in raw egg yolk of hens fed on different diets.

Science.gov (United States)

Plagemann, Ina; Zelena, Kateryna; Krings, Ulrich; Berger, Ralf G

2011-08-30

Recent studies have suggested that the composition of lipophilic components of egg yolk is influenced by the feed. The aim of the present study was to isolate volatile flavours from egg yolk after different feeding trials using solvent extraction and thin layer high-vacuum distillation. The resulting aroma extract was analysed by various gas chromatographic techniques. Chickens were either fed with laying meal, laying meal plus cabbage and onion or laying meal plus rapeseed oil or held in free-range. The predominating odour impressions were described as onion-like. Comparing all analytical and sensory data of the flavour extracts, there were minimal differences among the respective samples. Free-range eggs contained fewer volatile compounds than the other samples, whereas rapeseed oil supplementation caused an enrichment of sulfur compounds. While data from gas chromatography/flame ionisation detection, gas chromatography/mass spectrometry and gas chromatography/olfactometry were less conclusive, the results from sulfur-specific analysis using gas chromatography/flame photometric detection showed a considerable effect. However, because of the low abundance of sulfur compounds in the yolk, these differences are not expected to be perceivable by the consumer. Copyright © 2011 Society of Chemical Industry.

Volatility and leachability of heavy metals and radionuclides in thermally treated HEPA filter media generated from nuclear facilities

International Nuclear Information System (INIS)

Yoon, In-Ho; Choi, Wang-Kyu; Lee, Suk-Chol; Min, Byung-Youn; Yang, Hee-Chul; Lee, Kune-Woo

2012-01-01

Highlights: ► Thermally treated HEPA filter media was transformed into glassy bulk materials. ► Main radionuclide and heavy metal were Cs-137 and Zn. ► Cs and Zn were transformed into stable form without volatilization and leaching. ► The proposed technique is simple and energy efficient procedure. - Abstract: The purpose of the present study was to apply thermal treatments to reduce the volume of HEPA filter media and to investigate the volatility and leachability of heavy metals and radionuclides during thermal treatment. HEPA filter media were transformed to glassy bulk material by thermal treatment at 900 °C for 2 h. The most abundant heavy metal in the HEPA filter media was Zn, followed by Sr, Pb and Cr, and the main radionuclide was Cs-137. The volatility tests showed that the heavy metals and radionuclides in radioactive HEPA filter media were not volatilized during the thermal treatment. PCT tests indicated that the leachability of heavy metals and radionuclides was relatively low compared to those of other glasses. XRD results showed that Zn and Cs reacted with HEPA filter media and were transformed into crystalline willemite (ZnO·SiO 2 ) and pollucite (Cs 2 OAl 2 O 3 4SiO 2 ), which are not volatile or leachable. The proposed technique for the volume reduction and transformation of radioactive HEPA filter media into glassy bulk material is a simple and energy efficient procedure without additives that can be performed at relatively low temperature compared with conventional vitrification process.

The abundance of pink-pigmented facultative methylotrophs in the root zone of plant species in invaded coastal sage scrub habitat.

Science.gov (United States)

Irvine, Irina C; Brigham, Christy A; Suding, Katharine N; Martiny, Jennifer B H

2012-01-01

Pink-pigmented facultative methylotrophic bacteria (PPFMs) are associated with the roots, leaves and seeds of most terrestrial plants and utilize volatile C(1) compounds such as methanol generated by growing plants during cell division. PPFMs have been well studied in agricultural systems due to their importance in crop seed germination, yield, pathogen resistance and drought stress tolerance. In contrast, little is known about the PPFM abundance and diversity in natural ecosystems, let alone their interactions with non-crop species. Here we surveyed PPFM abundance in the root zone soil of 5 native and 5 invasive plant species along ten invasion gradients in Southern California coastal sage scrub habitat. PPFMs were present in every soil sample and ranged in abundance from 10(2) to 10(5) CFU/g dry soil. This abundance varied significantly among plant species. PPFM abundance was 50% higher in the root zones of annual or biennial species (many invasives) than perennial species (all natives). Further, PPFM abundance appears to be influenced by the plant community beyond the root zone; pure stands of either native or invasive species had 50% more PPFMs than mixed species stands. In sum, PPFM abundance in the root zone of coastal sage scrub plants is influenced by both the immediate and surrounding plant communities. The results also suggest that PPFMs are a good target for future work on plant-microorganism feedbacks in natural ecosystems.

The Composition of Comet C/2009 PI (Garradd) from Infrared Spectroscopy: Evidence for an Oxygen-Rich Heritage?

Science.gov (United States)

DiSanti, M. A.; Bonev, B. P.; Villanueva, G. L.; Paganini, L.; Mumma, M. J.; Charnley, S. B.; Keane, J. V.; Meech, K. J.; Blake, G. A.; Boehnhardt, H.;

The Composition of Comet C/2009 P1 (Garradd) from Infrared Spectroscopy: Evidence for an Oxygen-Rich Heritage?

Science.gov (United States)

DiSanti, M. A.; Bonev, B. P.; Villaneueva, G. L.; Paganini, L.; Mumma, M. J.; Charnley, S. B.; Keane, J. V.; Blake, G. A.; Boehnhardt, H.; Lippi, M.

2012-01-01

Comets retain relatively primitive icy material remaining from the epoch of Solar System formation, however the extent to which their ices are modified remains a key question in cometary science. One way to address this is to measure the relative abundances of primary (parent) volatiles in comets (i.e., those ices native to the nucleus). High-resolution (lambda/delta lambda greater than 10(exp 4)) infrared spectroscopy is a powerful tool for measuring parent volatiles in comets through their vibrational emissions in the approximately 3-5 micrometer region. With modern instrumentation on world-class telescopes, we can quantify a multitude of species (e.g., H2O, C2H2, CH4, C2H6, CO, H2CO, CH3OH, HCN, NH3), even in comets with modest gas production. In space environments, compounds of keen interest to astrobiology could originate from HCN and NH3 (leading to amino acids), H2CO (leading to sugars), or C2H6, and CH4 (suggested precursors of ethyl- and methylamine). Measuring the abundances of these precursor molecules and their variability among comets contributes to understanding the synthesis of the more complex prebiotic compounds.

(32)S/(33)S abundance as a function of galactocentric radius in the Milky Way

International Nuclear Information System (INIS)

Greenhouse, M.A.; Thronson, H.A. Jr.

1986-01-01

Astration of heavy elements by the stars of the Milky Way forms a fossil record which may preserve spacial distribution of the mass function for the stars in the galaxy. Sulfur is among the last common element for which the relative abundance of its various isotopes have yet to be completely measured within our galaxy. Explosive oxygen burning in massive stars is thought to be the process which dominates sulfur production within stars. There models predict that the various isotopes (S-32, S-33, S-34) are formed in relative abundance which depend strongly upon the mass of the parent star. This relative abundance is thought to be unaffected by subsequent stellar procesing since all important sinks of sulfur destroy it without regard for isotopic form. Hence the spacial variation of the mass function (MF) can be studied by measuring the abundance variation of sulfur isotopes in the galaxy provided that the product yields for these isotopes are known accurately as a function of stellar mass

PERUBAHAN KOMPONEN VOLATIL SELAMA FERMENTASI KECAP [Change Volatile Components During Soy Sauce Fermentation

Directory of Open Access Journals (Sweden)

Anton Apriyantono1

2004-08-01

Full Text Available A study has been conducted to investigate changes of volatile components during soy sauce fermentation. During the fermentation, many volatile components produced may contribute to soy sauce flavor. THe volatile identified by GC-MS werw classified into hydrocarbon (15, alcohol (15, aldehyde (14, ester (14, ketone (9, benzene derivative (11, fatty acid (9, furan (5, terpenoid (18, pyrazine (3, thiazole (1, pyridine (1 and sulfur containing compound (2.Concentration of compounds found in almost all fermentation steps, such as hexanal and benzaldehyde did. These compounds may be derived from raw soybean, since they were all present in raw soybean and their concentration did not change during fermentation. Concentration of palmitic acid and benzeneacetaldehyde, in general, increased during all fermentation steps. They are probably derived from lipid degradation or microorganism activities. Concentrations of some fatty acids, esters and hydrocarbons, such as linoleic acid, methyl palmitate and heptadecane increased during salt fermentation only. Concentration of some other compounds, such as 2,4 decadienal decreased or undetected during fermentation.The absence of some volatile compounds, e.g. (E-nerolidol and (E,E-famesol in boiled soybean which were previously present in raw soybean may be due to evaporation of these compounds during boiling. Some volatile compounds such as, methyl heptadecanoate and few aromatic alcohols are likely derived from Aspergillus sojae, since these compounds were identified only in 0 day koji

Maximum likelihood approach for several stochastic volatility models

International Nuclear Information System (INIS)

Camprodon, Jordi; Perelló, Josep

2012-01-01

Volatility measures the amplitude of price fluctuations. Despite it being one of the most important quantities in finance, volatility is not directly observable. Here we apply a maximum likelihood method which assumes that price and volatility follow a two-dimensional diffusion process where volatility is the stochastic diffusion coefficient of the log-price dynamics. We apply this method to the simplest versions of the expOU, the OU and the Heston stochastic volatility models and we study their performance in terms of the log-price probability, the volatility probability, and its Mean First-Passage Time. The approach has some predictive power on the future returns amplitude by only knowing the current volatility. The assumed models do not consider long-range volatility autocorrelation and the asymmetric return-volatility cross-correlation but the method still yields very naturally these two important stylized facts. We apply the method to different market indices and with a good performance in all cases. (paper)

Characterization of Four Popular Sweet Cherry Cultivars Grown in Greece by Volatile Compound and Physicochemical Data Analysis and Sensory Evaluation

Directory of Open Access Journals (Sweden)

Maria V. Vavoura

2015-01-01

Full Text Available Volatile compounds, physicochemical and sensory attributes of four sweet cherry cultivars (Canada giant, Ferrovia, Lapins and Skeena grown in Northern Greece were determined. Eighteen volatile compounds were identified and semi-quantified in cherries using solid phase micro extraction in combination with gas chromatography/mass spectrometry (SPME-GC/MS. Carbonyl compounds were the most abundant in sweet cherry aroma, followed by alcohols, esters and hydrocarbons/terpenes. Cherry cultivars in order of increasing amounts of volatiles were: Lapins < Canada giant < Ferrovia < Skeena. Physicochemical parameters determined included: titratable acidity (TA, pH, total soluble solids (TSS, maturity index (MI and total phenolic content (TPC. TA ranged between 0.21 and 0.28 g malic acid/100 g fresh weight (FW. The pH ranged between 3.81 and 3.96. TSS ranged between 13.00 and 16.00 °Brix. MI ranged between 51.8 and 75.0. TPC ranged between 95.14 and 170.35 mg gallic acid equivalents (GAE/100 g FW. Sensory evaluation showed that cherry colour, in order of increasing intensity, was: Canada giant < Ferrovia < Lapins < Skeena. Respective order for cherry firmness was: Canada giant < Lapins ≤ Ferrovia < Skeena and for flavour: Lapins < Canada giant < Skeena ≤ Ferrovia. Correlation of volatiles to physicochemical and sensory attributes showed varying trends.

Current status of fluoride volatility method development

Energy Technology Data Exchange (ETDEWEB)

Uhlir, J.; Marecek, M.; Skarohlid, J. [UJV - Nuclear Research Institute, Research Centre Rez, CZ-250 68 Husinec - Rez 130 (Czech Republic)

2013-07-01

The Fluoride Volatility Method is based on a separation process, which comes out from the specific property of uranium, neptunium and plutonium to form volatile hexafluorides whereas most of fission products (mainly lanthanides) and higher transplutonium elements (americium, curium) present in irradiated fuel form nonvolatile tri-fluorides. Fluoride Volatility Method itself is based on direct fluorination of the spent fuel, but before the fluorination step, the removal of cladding material and subsequent transformation of the fuel into a powdered form with a suitable grain size have to be done. The fluorination is made with fluorine gas in a flame fluorination reactor, where the volatile fluorides (mostly UF{sub 6}) are separated from the non-volatile ones (trivalent minor actinides and majority of fission products). The subsequent operations necessary for partitioning of volatile fluorides are the condensation and evaporation of volatile fluorides, the thermal decomposition of PuF{sub 6} and the finally distillation and sorption used for the purification of uranium product. The Fluoride Volatility Method is considered to be a promising advanced pyrochemical reprocessing technology, which can mainly be used for the reprocessing of oxide spent fuels coming from future GEN IV fast reactors.

Stochastic volatility and stochastic leverage

DEFF Research Database (Denmark)

Veraart, Almut; Veraart, Luitgard A. M.

This paper proposes the new concept of stochastic leverage in stochastic volatility models. Stochastic leverage refers to a stochastic process which replaces the classical constant correlation parameter between the asset return and the stochastic volatility process. We provide a systematic...... treatment of stochastic leverage and propose to model the stochastic leverage effect explicitly, e.g. by means of a linear transformation of a Jacobi process. Such models are both analytically tractable and allow for a direct economic interpretation. In particular, we propose two new stochastic volatility...... models which allow for a stochastic leverage effect: the generalised Heston model and the generalised Barndorff-Nielsen & Shephard model. We investigate the impact of a stochastic leverage effect in the risk neutral world by focusing on implied volatilities generated by option prices derived from our new...

Molecular characterization and volatility evolution of α-pinene ozonolysis SOA during isothermal evaporations

Science.gov (United States)

D'Ambro, E.; Schobesberger, S.; Lopez-Hilfiker, F.; Shilling, J. E.; Lee, B. H.; Thornton, J. A.

2017-12-01

α-Pinene (C10H16), the most abundantly emitted monoterpene, is a large contributor to global biogenic secondary organic aerosol (SOA) budgets due to its high SOA yields upon oxidation. We probe the volatility and evaporation behavior upon dilution of α-pinene SOA to further our understanding of the nascent volatility distribution, viscosity, and how these evolve in time absent photochemical oxidation. We present molecular composition measurements of the gas and particle phases of α-pinene ozonolysis SOA formed at 0% and 50% relative humidity (RH), followed by room-temperature evaporation in ultra-high purity N2 humidified to 20-90% RH. Experiments were performed in the Pacific Northwest National Laboratory 10.6 m3 and the University of Washington 0.7 m3 environmental chambers utilizing a Filter Inlet for Gases and AEROsols (FIGAERO) coupled to a high-resolution time of flight chemical ionization mass spectrometer utilizing iodide adduct ionization. We present novel insights into the total mass that evaporates as a function of time from 10 min to 24 hours without heating, the molecular speciation of the evaporate, as well as the effective volatility and composition of the SOA mass remaining. Consistent with previous studies, we find two stages of evaporation: a rapid loss of a large portion of the total signal over the course of ≤3 hours, followed by a stage of much slower evaporation over the proceeding 21 hours. Varying the RH of formation effects evaporation rate on timescales ≤3 hours, however the mass fraction remaining after 24 hours converges to 30-50% under all formation and evaporation RHs. We simulate the evaporation behavior and remaining fractions desorbed via temperature programmed thermal desorption to derive effective saturation vapor concentrations, mass accommodation coefficients, and rates of chemical evolution producing both higher and lower volatility components during the evaporation time period.

Modelling the Volatility-Return Trade-off when Volatility may be Nonstationary

DEFF Research Database (Denmark)

Dahl, Christian Møller; Iglesias, Emma M.

In this paper a new GARCH-M type model, denoted the GARCH-AR, is proposed. In particular, it is shown that it is possible to generate a volatility-return trade-off in a regression model simply by introducing dynamics in the standardized disturbance process. Importantly, the volatility in the GARCH......, we provide an empirical illustration showing the empirical relevance of the GARCH-AR model based on modelling a wide range of leading US stock return series....

The Abundance of Pink-Pigmented Facultative Methylotrophs in the Root Zone of Plant Species in Invaded Coastal Sage Scrub Habitat

OpenAIRE

Irvine, Irina C.; Brigham, Christy A.; Suding, Katharine N.; Martiny, Jennifer H.

2012-01-01

Pink-pigmented facultative methylotrophic bacteria (PPFMs) are associated with the roots, leaves and seeds of most terrestrial plants and utilize volatile C(1) compounds such as methanol generated by growing plants during cell division. PPFMs have been well studied in agricultural systems due to their importance in crop seed germination, yield, pathogen resistance and drought stress tolerance. In contrast, little is known about the PPFM abundance and diversity in natural ecosystems, let alone...

Manure application and ammonia volatilization

NARCIS (Netherlands)

Huijsmans, J.F.M.

2003-01-01

Keywords: manure application, ammonia volatilization, environmental conditions, application technique, incorporation technique, draught force, work organization, costs Livestock manure applied on farmland is an important source of ammonia (NH3) volatilization, and NH3 is a major atmospheric

Emission of volatile sulfur compounds during composting of municipal solid waste (MSW)

International Nuclear Information System (INIS)

Zhang, Hongyu; Schuchardt, Frank; Li, Guoxue; Yang, Jinbing; Yang, Qingyuan

2013-01-01

Highlights: ► We compare the volatile sulfur compounds (VSCs) emissions during three types of municipal solid wastes (MSWs) composting. ► The VSCs released from the kitchen waste composting was significantly higher than that from 15–80 mm fraction of MSW. ► Among the five VSCs, H 2 S was the most abundant compound with 39.0–43.0% of total VSCs released. ► Addition of 20% cornstalks could significantly reduce the VSCs emissions during kitchen waste composting. - Abstract: Volatile sulfur compounds (VSCs) are the main source for malodor from composting plants. In this study, the VSCs generated from composting of 15–80 mm municipal solid waste (T0), kitchen waste (T1) and kitchen waste mixed dry cornstalks (T2) were measured in 60 L reactors with forced aeration for a period of 30 days. The VSCs detected in all treatments were hydrogen sulfide (H 2 S), methyl mercaptan (MM), dimethyl sulfide (DMS), carbon bisulfide (CS 2 ) and dimethyl disulfide (DMDS). Over 90% of the VSCs emissions occurred during the first 15 days, and reached their peak values at days 4–7. The emission profiles of five VSCs species were significantly correlated with internal materials temperature and outlet O 2 concentration (p −1 (dry matter) for T0, T1 and T2, respectively. Among the five VSCs, H 2 S was the most abundant compound with 39.0–43.0% of total VSCs released. Composting of kitchen waste from separate collection posed a negative influence on the VSC and leachate production because of its high moisture content. An addition of dry cornstalks at a mixing ratio of 4:1 (wet weight) could significantly reduce the VSCs emissions and avoid leachate. Compared to pure kitchen waste, VSCs were reduced 66.8%

First results from the Mojave Volatiles Prospector (MVP) Field Campaign, a Lunar Polar Rover Mission Analog

Science.gov (United States)

Heldmann, J. L.; Colaprete, A.; Cook, A.; Deans, M. C.; Elphic, R. C.; Lim, D. S. S.; Skok, J. R.

2014-12-01

The Mojave Volatiles Prospector (MVP) project is a science-driven field program with the goal to produce critical knowledge for conducting robotic exploration of the Moon. MVP will feed science, payload, and operational lessons learned to the development of a real-time, short-duration lunar polar volatiles prospecting mission. MVP achieves these goals through a simulated lunar rover mission to investigate the composition and distribution of surface and subsurface volatiles in a natural and a priori unknown environment within the Mojave Desert, improving our understanding of how to find, characterize, and access volatiles on the Moon. The MVP field site is the Mojave Desert, selected for its low, naturally occurring water abundance. The Mojave typically has on the order of 2-6% water, making it a suitable lunar analog for this field test. MVP uses the Near Infrared and Visible Spectrometer Subsystem (NIRVSS), Neutron Spectrometer Subsystem (NSS), and a downward facing GroundCam camera on the KREX-2 rover to investigate the relationship between the distribution of volatiles and soil crust variation. Through this investigation, we mature robotic in situ instruments and concepts of instrument operations, improve ground software tools for real time science, and carry out publishable research on the water cycle and its connection to geomorphology and mineralogy in desert environments. A lunar polar rover mission is unlike prior space missions and requires a new concept of operations. The rover must navigate 3-5 km of terrain and examine multiple sites in in just ~6 days. Operational decisions must be made in real time, requiring constant situational awareness, data analysis and rapid turnaround decision support tools. This presentation will focus on the first science results and operational architecture findings from the MVP field deployment relevant to a lunar polar rover mission.

Inflation Volatility and the Inflation-Growth Tradeoff in India

OpenAIRE

Raghbendra Jha; Varsha S. Kulkarni

2012-01-01

This paper amends the New Keynesian Phillips curve model to include inflation volatility and tests the determinants of such volatility for India. It provides results on the determinants of inflation volatility and expected inflation volatility for OLS and ARDL (1,1) models and for change in inflation volatility and change in expected inflation volatility using ECM models. Output gap affects change in expected inflation volatility along (in the ECM model) and not in the other models. Major det...

Financial Development, Financial Structure, and Macroeconomic Volatility: Evidence from China

Directory of Open Access Journals (Sweden)

Feng Wei

2016-11-01

Full Text Available Using annual data from 1997–2014 of 30 provinces, municipalities, and autonomous regions, subdividing trended and cyclical volatility of macroeconomics and inflation, considering different indicators of financial development and financial structure, this paper investigated the impact of financial development and financial structure on macroeconomic volatility. The empirical results found that (1 the trended and cyclical volatility of the previous macroeconomic period had a significantly positive impact on that of the current period, and the impact of trended volatility was greater than that of cyclical volatility; (2 financial development had a significantly negative impact on macroeconomic cyclical volatility through inflation cyclical volatility, but inflation trended volatility would amplify macroeconomic volatility; financial markets have no significant effect on macroeconomic volatility; financial structure measured with the ratio of stock market turnover and the efficiency of the financial development had a significant positive impact on macroeconomic cyclical volatility; and (3 inflation trended volatility had a significantly negative impact on macroeconomic cyclical volatility and trended volatility, while inflation cyclical volatility had a significantly positive impact on macroeconomic cyclical volatility.

Effects of Idiosyncratic Volatility in Asset Pricing

Directory of Open Access Journals (Sweden)

André Luís Leite

2016-04-01

Full Text Available This paper aims to evaluate the effects of the aggregate market volatility components - average volatility and average correlation - on the pricing of portfolios sorted by idiosyncratic volatility, using Brazilian data. The study investigates whether portfolios with high and low idiosyncratic volatility - in relation to the Fama and French model (1996 - have different exposures to innovations in average market volatility, and consequently, different expectations for return. The results are in line with those found for US data, although they portray the Brazilian reality. Decomposition of volatility allows the average volatility component, without the disturbance generated by the average correlation component, to better price the effects of a worsening or an improvement in the investment environment. This result is also identical to that found for US data. Average variance should thus command a risk premium. For US data, this premium is negative. According to Chen and Petkova (2012, the main reason for this negative sign is the high level of investment in research and development recorded by companies with high idiosyncratic volatility. As in Brazil this type of investment is significantly lower than in the US, it was expected that a result with the opposite sign would be found, which is in fact what occurred.

American option pricing with stochastic volatility processes

Directory of Open Access Journals (Sweden)

Ping LI

2017-12-01

Full Text Available In order to solve the problem of option pricing more perfectly, the option pricing problem with Heston stochastic volatility model is considered. The optimal implementation boundary of American option and the conditions for its early execution are analyzed and discussed. In view of the fact that there is no analytical American option pricing formula, through the space discretization parameters, the stochastic partial differential equation satisfied by American options with Heston stochastic volatility is transformed into the corresponding differential equations, and then using high order compact finite difference method, numerical solutions are obtained for the option price. The numerical experiments are carried out to verify the theoretical results and simulation. The two kinds of optimal exercise boundaries under the conditions of the constant volatility and the stochastic volatility are compared, and the results show that the optimal exercise boundary also has stochastic volatility. Under the setting of parameters, the behavior and the nature of volatility are analyzed, the volatility curve is simulated, the calculation results of high order compact difference method are compared, and the numerical option solution is obtained, so that the method is verified. The research result provides reference for solving the problems of option pricing under stochastic volatility such as multiple underlying asset option pricing and barrier option pricing.

HS-SPME-GC-MS ANALYSIS OF VOLATILE AND SEMI-VOLATILE COMPOUNDS FROM DRIED LEAVES OF Mikania glomerata Sprengel

Directory of Open Access Journals (Sweden)

Esmeraldo A. Cappelaro

2015-03-01

Full Text Available This paper reports on the identification of volatile and semi-volatile compounds and a comparison of the chromatographic profiles obtained by Headspace Solid-Phase Microextraction/Gas Chromatography with Mass Spectrometry detection (HS-SPME-GC-MS of dried leaves of Mikania glomerata Sprengel (Asteraceae, also known as 'guaco.' Three different types of commercial SPME fibers were tested: polydimethylsiloxane (PDMS, polydimethylsiloxane/divinylbenzene (PDMS/DVB and polyacrylate (PA. Fifty-nine compounds were fully identified by HS-SPME-HRGC-MS, including coumarin, a marker for the quality control of guaco-based phytomedicines; most of the other identified compounds were mono- and sesquiterpenes. PA fibers performed better in the analysis of coumarin, while PDMS-DVB proved to be the best choice for a general and non-selective analysis of volatile and semi-volatile guaco-based compounds. The SPME method is faster and requires a smaller sample than conventional hydrodistillation of essential oils, providing a general overview of the volatile and semi-volatile compounds of M. glomerata.

Ammonia volatilization from sows on grassland

Science.gov (United States)

Sommer, S. G.; Søgaard, H. T.; Møller, H. B.; Morsing, S.

According to regulations, sows with piglets on organic farms must graze on pastures. Volatilization of ammonia (NH 3) from urine patches may represent a significant source of nitrogen (N) loss from these farms. Inputs of N are low on organic farms and losses may reduce crop production. This study examined spatial variations in NH 3 volatilization using a movable dynamic chamber, and the pH and total ammoniacal nitrogen (TAN) content in the topsoil of pastures with grazing sows was measured during five periods between June 1998 and May 1999. Gross NH 3 volatilization from the pastures was also measured with an atmospheric mass balance technique during seven periods from September 1997 until June 1999. The dynamic chamber study showed a high variation in NH 3 volatilization because of the distribution of urine; losses were between 0 and 2.8 g NH 3-N m -2 day -1. Volatilization was highest near the feeding area and the huts, where the sows tended to urinate. Ammonia volatilization rate was linearly related to the product of NH 3 concentration in the boundary layer and wind speed. The NH 3 in the boundary layer was in equilibrium with NH 3 in soil solution. Gross NH 3 volatilization was in the range 0.07-2.1 kg NH 3-N ha -1 day -1 from a pasture with 24 sows ha -1. Ammonia volatilization was related to the amount of feed given to the sows, incident solar radiation and air temperature during measuring periods, and also to temperature, incident solar radiation and rain 1-2 days before measurements. Annual ammonia loss was 4.8 kg NH 3-N sow -1.

Herbivore-induced blueberry volatiles and intra-plant signaling.

Science.gov (United States)

Rodriguez-Saona, Cesar R

2011-12-18

Herbivore-induced plant volatiles (HIPVs) are commonly emitted from plants after herbivore attack. These HIPVs are mainly regulated by the defensive plant hormone jasmonic acid (JA) and its volatile derivative methyl jasmonate (MeJA). Over the past 3 decades researchers have documented that HIPVs can repel or attract herbivores, attract the natural enemies of herbivores, and in some cases they can induce or prime plant defenses prior to herbivore attack. In a recent paper, I reported that feeding by gypsy moth caterpillars, exogenous MeJA application, and mechanical damage induce the emissions of volatiles from blueberry plants, albeit differently. In addition, blueberry branches respond to HIPVs emitted from neighboring branches of the same plant by increasing the levels of JA and resistance to herbivores (i.e., direct plant defenses), and by priming volatile emissions (i.e., indirect plant defenses). Similar findings have been reported recently for sagebrush, poplar, and lima beans. Here, I describe a push-pull method for collecting blueberry volatiles induced by herbivore (gypsy moth) feeding, exogenous MeJA application, and mechanical damage. The volatile collection unit consists of a 4 L volatile collection chamber, a 2-piece guillotine, an air delivery system that purifies incoming air, and a vacuum system connected to a trap filled with Super-Q adsorbent to collect volatiles. Volatiles collected in Super-Q traps are eluted with dichloromethane and then separated and quantified using Gas Chromatography (GC). This volatile collection method was used in my study to investigate the volatile response of undamaged branches to exposure to volatiles from herbivore-damaged branches within blueberry plants. These methods are described here. Briefly, undamaged blueberry branches are exposed to HIPVs from neighboring branches within the same plant. Using the same techniques described above, volatiles emitted from branches after exposure to HIPVs are collected and

Electricity market price volatility: The case of Ontario

International Nuclear Information System (INIS)

Zareipour, Hamidreza; Bhattacharya, Kankar; Canizares, Claudio A.

2007-01-01

Price volatility analysis has been reported in the literature for most competitive electricity markets around the world. However, no studies have been published yet that quantify price volatility in the Ontario electricity market, which is the focus of the present paper. In this paper, a comparative volatility analysis is conducted for the Ontario market and its neighboring electricity markets. Volatility indices are developed based on historical volatility and price velocity concepts, previously applied to other electricity market prices, and employed in the present work. The analysis is carried out in two scenarios: in the first scenario, the volatility indices are determined for the entire price time series. In the second scenario, the price time series are broken up into 24 time series for each of the 24 h and volatility indices are calculated for each specific hour separately. The volatility indices are also applied to the locational marginal prices of several pricing points in the New England, New York, and PJM electricity markets. The outcomes reveal that price volatility is significantly higher in Ontario than the three studied neighboring electricity markets. Furthermore, comparison of the results of this study with similar findings previously published for 15 other electricity markets demonstrates that the Ontario electricity market is one of the most volatile electricity markets world-wide. This high volatility is argued to be associated with the fact that Ontario is a single-settlement, real-time market

Asymptotic Behavior of the Stock Price Distribution Density and Implied Volatility in Stochastic Volatility Models

International Nuclear Information System (INIS)

Gulisashvili, Archil; Stein, Elias M.

2010-01-01

We study the asymptotic behavior of distribution densities arising in stock price models with stochastic volatility. The main objects of our interest in the present paper are the density of time averages of the squared volatility process and the density of the stock price process in the Stein-Stein and the Heston model. We find explicit formulas for leading terms in asymptotic expansions of these densities and give error estimates. As an application of our results, sharp asymptotic formulas for the implied volatility in the Stein-Stein and the Heston model are obtained.

Dynamic Asset Allocation Strategies Based on Volatility, Unexpected Volatility and Financial Turbulence

OpenAIRE

Grimsrud, David Borkner

2015-01-01

Masteroppgave økonomi og administrasjon- Universitetet i Agder, 2015 This master thesis looks at unexpected volatility- and financial turbulence’s predictive ability, and exploit these measures of financial risk, together with volatility, to create three dynamic asset allocation strategies, and test if they can outperform a passive and naively diversified buy-and-hold strategy. The idea with the dynamic strategies is to increase the portfolio return by keeping the portfolio risk at a low a...

A nonparametric approach to forecasting realized volatility

OpenAIRE

Adam Clements; Ralf Becker

2009-01-01

A well developed literature exists in relation to modeling and forecasting asset return volatility. Much of this relate to the development of time series models of volatility. This paper proposes an alternative method for forecasting volatility that does not involve such a model. Under this approach a forecast is a weighted average of historical volatility. The greatest weight is given to periods that exhibit the most similar market conditions to the time at which the forecast is being formed...

Realized Beta GARCH: A Multivariate GARCH Model with Realized Measures of Volatility and CoVolatility

DEFF Research Database (Denmark)

Hansen, Peter Reinhard; Lunde, Asger; Voev, Valeri

We introduce a multivariate GARCH model that utilizes and models realized measures of volatility and covolatility. The realized measures extract information contained in high-frequency data that is particularly beneficial during periods with variation in volatility and covolatility. Applying the ...

Flower volatiles, crop varieties and bee responses.

Directory of Open Access Journals (Sweden)

Björn K Klatt

Full Text Available Pollination contributes to an estimated one third of global food production, through both the improvement of the yield and the quality of crops. Volatile compounds emitted by crop flowers mediate plant-pollinator interactions, but differences between crop varieties are still little explored. We investigated whether the visitation of crop flowers is determined by variety-specific flower volatiles using strawberry varieties (Fragaria x ananassa Duchesne and how this affects the pollination services of the wild bee Osmia bicornis L. Flower volatile compounds of three strawberry varieties were measured via headspace collection. Gas chromatography showed that the three strawberry varieties produced the same volatile compounds but with quantitative differences of the total amount of volatiles and between distinct compounds. Electroantennographic recordings showed that inexperienced females of Osmia bicornis had higher antennal responses to all volatile compounds than to controls of air and paraffin oil, however responses differed between compounds. The variety Sonata was found to emit a total higher level of volatiles and also higher levels of most of the compounds that evoked antennal responses compared with the other varieties Honeoye and Darselect. Sonata also received more flower visits from Osmia bicornis females under field conditions, compared with Honeoye. Our results suggest that differences in the emission of flower volatile compounds among strawberry varieties mediate their attractiveness to females of Osmia bicornis. Since quality and quantity of marketable fruits depend on optimal pollination, a better understanding of the role of flower volatiles in crop production is required and should be considered more closely in crop-variety breeding.

The multivariate supOU stochastic volatility model

DEFF Research Database (Denmark)

Barndorff-Nielsen, Ole; Stelzer, Robert

Using positive semidefinite supOU (superposition of Ornstein-Uhlenbeck type) processes to describe the volatility, we introduce a multivariate stochastic volatility model for financial data which is capable of modelling long range dependence effects. The finiteness of moments and the second order...... structure of the volatility, the log returns, as well as their "squares" are discussed in detail. Moreover, we give several examples in which long memory effects occur and study how the model as well as the simple Ornstein-Uhlenbeck type stochastic volatility model behave under linear transformations....... In particular, the models are shown to be preserved under invertible linear transformations. Finally, we discuss how (sup)OU stochastic volatility models can be combined with a factor modelling approach....

Forecasting Exchange Rate Volatility in the Presence of Jumps

DEFF Research Database (Denmark)

Busch, Thomas; Christensen, Bent Jesper; Nielsen, Morten Ørregaard

We study measures of foreign exchange rate volatility based on high-frequency (5-minute) $/DM exchange rate returns using recent nonparametric statistical techniquesto compute realized return volatility and its separate continuous sample path and jumpcomponents, and measures based on prices...... of exchange rate futures options, allowingcalculation of option implied volatility. We find that implied volatility is an informationallyefficient but biased forecast of future realized exchange rate volatility. Furthermore,we show that log-normality is an even better distributional approximation...... for impliedvolatility than for realized volatility in this market. Finally, we show that the jump componentof future realized exchange rate volatility is to some extent predictable, and thatoption implied volatility is the dominant forecast of the future jump component....

Dynamic Factor Models for the Volatility Surface

DEFF Research Database (Denmark)

van der Wel, Michel; Ozturk, Sait R.; Dijk, Dick van

The implied volatility surface is the collection of volatilities implied by option contracts for different strike prices and time-to-maturity. We study factor models to capture the dynamics of this three-dimensional implied volatility surface. Three model types are considered to examine desirable...

Fundamental volatility is regime specific

NARCIS (Netherlands)

Arnold, I.J.M.; MacDonald, R.; Vries, de C.G.

2006-01-01

A widely held notion holds that freely floating exchange rates are excessively volatile when judged against fundamentals and when moving from fixed to floating exchange rates. We re-examine the data and conclude that the disparity between the fundamentals and exchange rate volatility is more

Consistent ranking of volatility models

DEFF Research Database (Denmark)

Hansen, Peter Reinhard; Lunde, Asger

2006-01-01

We show that the empirical ranking of volatility models can be inconsistent for the true ranking if the evaluation is based on a proxy for the population measure of volatility. For example, the substitution of a squared return for the conditional variance in the evaluation of ARCH-type models can...... variance in out-of-sample evaluations rather than the squared return. We derive the theoretical results in a general framework that is not specific to the comparison of volatility models. Similar problems can arise in comparisons of forecasting models whenever the predicted variable is a latent variable....

Volatile, anthocyanidin, quality and sensory changes in rabbiteye blueberry from whole fruit through pilot plant juice processing.

Science.gov (United States)

Beaulieu, John C; Stein-Chisholm, Rebecca E; Lloyd, Steven W; Bett-Garber, Karen L; Grimm, Casey C; Watson, Michael A; Lea, Jeanne M

2017-01-01

High antioxidant content and keen marketing have increased blueberry demand and increased local production which in turn mandates new uses for abundant harvests. Pilot scale processes were employed to investigate the anthocyanidin profiles, qualitative volatile compositions, and sensorial attributes in not-from-concentrate (NFC) 'Tifblue' rabbiteye blueberry juices. Processing prior to pasteurization generally resulted in increased L * and hue angle color, while a * , b * , and C * decreased. After 4 months pasteurized storage, non-clarified juice (NCP) lost 73.8% of total volatiles compared with 70.9% in clarified juice (CJP). There was a total anthocyanidin decrease of 84.5% and 85.5% after 4 months storage in NCP and CJP, respectively. Storage itself resulted in only 14.2% and 7.2% anthocyanidin loss after pasteurization in NCP and CJP. Storage significantly affected nine flavor properties in juices; however, there were no significant differences in the blueberry, strawberry, purple grape, floral, sweet aroma, or sweet tastes between processed and stored juices. NFC pasteurized blueberry juices maintained desirable flavors even though highly significant volatile and anthocyanidin losses occurred through processing. Maintenance of color and flavor indicate that NFC juices could have an advantage over more abusive methods often used in commercial juice operations. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

Aroma volatiles obtained at harvest by HS-SPME/GC-MS and INDEX/MS-E-nose fingerprint discriminate climacteric behaviour in melon fruit.

Science.gov (United States)

Chaparro-Torres, Libia A; Bueso, María C; Fernández-Trujillo, Juan P

2016-05-01

Melon aroma volatiles were extracted at harvest from juice of a climacteric near-isogenic line (NIL) SC3-5-1 with two quantitative trait loci (QTLs) introgressed which produced climacteric behaviour and its non-climacteric parental (PS) using two methodologies of analysis: static headspace solid phase micro-extraction (HS-SPME) by gas chromatography-mass spectrometry (GC-MS) and inside needle dynamic extraction (INDEX) by MS-based electronic nose (MS-E-nose). Of the 137 volatiles compounds identified, most were found at significantly higher concentrations in SC3-5-1 than in PS in both seasons. These volatiles were mostly esters, alcohols, sulfur-derived esters and even some aldehydes and others. The number of variables with high correlation values was reduced by using correlation network analysis. Partial least squares-discriminant analysis (PLS-DA) achieved the correct classification of PS and SC3-5-1. The ions m/z 74, 91, 104, 105, 106 and 108, mainly volatile derivatives precursor phenylalanine, were the most discriminant in SC3-5-1 and PS. As many as 104 QTLs were mapped in season 1 and at least 78 QTLs in each season with an effect above the PS mean. GC-MS gave better discrimination than E-nose. Most of the QTLs that mapped in both seasons enhanced aroma volatiles associated with climacteric behaviour. © 2015 Society of Chemical Industry.

Sulfur volatiles from Allium spp. affect Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), response to citrus volatiles.

Science.gov (United States)

Mann, R S; Rouseff, R L; Smoot, J M; Castle, W S; Stelinski, L L

2011-02-01

The Asian citrus psyllid, Diaphorina citri Kuwayama, vectors Candidatus Liberibacter asiaticus (Las) and Candidatus Liberibacter americanus (Lam), the presumed causal agents of huanglongbing. D. citri generally rely on olfaction and vision for detection of host cues. Plant volatiles from Allium spp. (Alliaceae) are known to repel several arthropod species. We examined the effect of garlic chive (A. tuberosum Rottl.) and wild onion (A. canadense L.) volatiles on D. citri behaviour in a two-port divided T-olfactometer. Citrus leaf volatiles attracted significantly more D. citri adults than clean air. Volatiles from crushed garlic chive leaves, garlic chive essential oil, garlic chive plants, wild onion plants and crushed wild onion leaves all repelled D. citri adults when compared with clean air, with the first two being significantly more repellent than the others. However, when tested with citrus volatiles, only crushed garlic chive leaves and garlic chive essential oil were repellent, and crushed wild onions leaves were not. Analysis of the headspace components of crushed garlic chive leaves and garlic chive essential oil by gas chromatography-mass spectrometry revealed that monosulfides, disulfides and trisulfides were the primary sulfur volatiles present. In general, trisulfides (dimethyl trisulfide) inhibited the response of D. citri to citrus volatiles more than disulfides (dimethyl disulfide, allyl methyl disulfide, allyl disulfide). Monosulfides did not affect the behaviour of D. citri adults. A blend of dimethyl trisulfide and dimethyl disulfide in 1:1 ratio showed an additive effect on inhibition of D. citri response to citrus volatiles. The plant volatiles from Allium spp. did not affect the behaviour of the D. citri ecto-parasitoid Tamarixia radiata (Waterston). Thus, Allium spp. or the tri- and di-sulphides could be integrated into management programmes for D. citri without affecting natural enemies.

Aerosol volatility in a boreal forest environment

Science.gov (United States)

Häkkinen, S. A. K.; ńijälä, M.; Lehtipalo, K.; Junninen, H.; Virkkula, A.; Worsnop, D. R.; Kulmala, M.; Petäjä, T.; Riipinen, I.

2012-04-01

Climate and health effects of atmospheric aerosols are determined by their properties such as their chemical composition. Aerosol chemical composition can be studied indirectly by measuring volatility of aerosol particles. The volatility of submicron aerosol particles (20-500 nm) was studied in a boreal forest site at SMEAR II (Station for Measuring Ecosystem-Atmosphere Relations II) station (Vesala et al., 1998) in Hyytiälä, Finland, during 01/2008-05/2010. The instrument used for the measurements was VDMPS (Volatility Differential Mobility Particle Sizer), which consists of two separate instruments: DMPS (Differential Mobility Particle Sizer, Aalto et al., 2001) and TD (Thermodenuder, Wehner et al., 2002). Aerosol evaporation was examined by heating the aerosol and comparing the total aerosol mass before and after heating. In the VDMPS system ambient aerosol sample was heated up to temperatures ranging from 80 °C to 280 °C. The higher the heating temperature was the more aerosol material was evaporated. There was a non-volatile residual present in aerosol particles when heated up to 280 °C. This residual explained (20±8)% of the total aerosol mass. Aerosol non-volatile mass fraction was highest during winter and smallest during summer months. The role of black carbon in the observed non-volatile residual was determined. Black carbon explained 40 to 90% of the non-volatile mass. Especially during colder seasons noticeable amount of non-volatile material, something else than black carbon, was observed. According to Kalberer et al. (2004) some atmospheric organic species can form polymers that have high evaporation temperatures. Also low-volatile organic salts may contribute to the non-volatile aerosol (Smith et al., 2010). Aerosol mass composition measured directly with AMS (Aerosol Mass Spectrometer, Jayne et al., 2000) was analyzed in order to examine the properties of the non-volatile material (other than black carbon). The AMS measurements were performed

The abundance of pink-pigmented facultative methylotrophs in the root zone of plant species in invaded coastal sage scrub habitat.

Directory of Open Access Journals (Sweden)

Irina C Irvine

Full Text Available Pink-pigmented facultative methylotrophic bacteria (PPFMs are associated with the roots, leaves and seeds of most terrestrial plants and utilize volatile C(1 compounds such as methanol generated by growing plants during cell division. PPFMs have been well studied in agricultural systems due to their importance in crop seed germination, yield, pathogen resistance and drought stress tolerance. In contrast, little is known about the PPFM abundance and diversity in natural ecosystems, let alone their interactions with non-crop species. Here we surveyed PPFM abundance in the root zone soil of 5 native and 5 invasive plant species along ten invasion gradients in Southern California coastal sage scrub habitat. PPFMs were present in every soil sample and ranged in abundance from 10(2 to 10(5 CFU/g dry soil. This abundance varied significantly among plant species. PPFM abundance was 50% higher in the root zones of annual or biennial species (many invasives than perennial species (all natives. Further, PPFM abundance appears to be influenced by the plant community beyond the root zone; pure stands of either native or invasive species had 50% more PPFMs than mixed species stands. In sum, PPFM abundance in the root zone of coastal sage scrub plants is influenced by both the immediate and surrounding plant communities. The results also suggest that PPFMs are a good target for future work on plant-microorganism feedbacks in natural ecosystems.

Abundance of introduced species at home predicts abundance away in herbaceous communities

Science.gov (United States)

Firn, Jennifer; Moore, Joslin L.; MacDougall, Andrew S.; Borer, Elizabeth T.; Seabloom, Eric W.; HilleRisLambers, Janneke; Harpole, W. Stanley; Cleland, Elsa E.; Brown, Cynthia S.; Knops, Johannes M.H.; Prober, Suzanne M.; Pyke, David A.; Farrell, Kelly A.; Bakker, John D.; O'Halloran, Lydia R.; Adler, Peter B.; Collins, Scott L.; D'Antonio, Carla M.; Crawley, Michael J.; Wolkovich, Elizabeth M.; La Pierre, Kimberly J.; Melbourne, Brett A.; Hautier, Yann; Morgan, John W.; Leakey, Andrew D.B.; Kay, Adam; McCulley, Rebecca; Davies, Kendi F.; Stevens, Carly J.; Chu, Cheng-Jin; Holl, Karen D.; Klein, Julia A.; Fay, Phillip A.; Hagenah, Nicole; Kirkman, Kevin P.; Buckley, Yvonne M.

2011-01-01

Many ecosystems worldwide are dominated by introduced plant species, leading to loss of biodiversity and ecosystem function. A common but rarely tested assumption is that these plants are more abundant in introduced vs. native communities, because ecological or evolutionary-based shifts in populations underlie invasion success. Here, data for 26 herbaceous species at 39 sites, within eight countries, revealed that species abundances were similar at native (home) and introduced (away) sites - grass species were generally abundant home and away, while forbs were low in abundance, but more abundant at home. Sites with six or more of these species had similar community abundance hierarchies, suggesting that suites of introduced species are assembling similarly on different continents. Overall, we found that substantial changes to populations are not necessarily a pre-condition for invasion success and that increases in species abundance are unusual. Instead, abundance at home predicts abundance away, a potentially useful additional criterion for biosecurity programmes.

Analysis of volatiles from irradiated yeast extract

International Nuclear Information System (INIS)

Liao Tao; Li Xin; Zu Xiaoyan; Chen Yuxia; Geng Shengrong

2013-01-01

The method for determination volatiles from irradiated yeast extract (YE) using headspace solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) was developed in this paper. The extraction conditions were optimized with reference to the peak area and number of volatiles as aldehyde, ketone, alcohol, acid, ester and sulfur compounds. The optimized conditions of HS-SPME for volatiles in irradiated YE were: divinyl benzene/Carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fiber, extration time 40 min, extraction temperature 40℃. The volatiles from YE irradiated by 0-19.8 kGy were detected using HS-SPME coupled with GC-MS. The results showed that only 15 volatiles were detected from no irradiated YE and main compounds were acetic acid, 2, 3-butanediol and 1-hexanol, 2-ethyl-. There were 40 volatiles detected from irradiated YE and the main compounds were acetic acid, phenylethyl alcohol, heptanal and nonanal. Compare to no irradiated yeast extract, the aldehyde, ketone, alkene and disulfide, dimethyl were produced by irradiating process. (authors)

Composition of sulla (Hedysarum coronarium L.) honey solvent extractives determined by GC/MS: norisoprenoids and other volatile organic compounds.

Science.gov (United States)

Jerković, Igor; Tuberoso, Carlo I G; Tuberso, Carlo I G; Gugić, Mirko; Bubalo, Dragan

2010-09-09

Samples of unifloral sulla (Hedysarum coronarum L.) honey from Sardinia (Italy) were analysed. To investigate the chemical composition of the honey volatiles two solvent systems were used for ultrasonic solvent extraction (USE): 1) a 1:2 (v/v) pentane and diethyl ether mixture and 2) dichloromethane. All the extracts were analysed by GC and GC/MS. These procedures have permitted the identification of 56 compounds that include norisoprenoids, benzene derivatives, aliphatic compounds and Maillard reaction products. Norisoprenoids were the major compounds in both extracts, dominated by vomifoliol (5.3-11.2%; 9.6-14.0%) followed by minor percentages of other norisoprenoids such as α-isophorone, 4-ketoisophorone, 3-oxo-α-ionol or 3-oxo-α-ionone. Other abundant single compounds in the extracts were 3-hydroxy-4-phenylbutan-2-one (0.8-5.4%; 0.6-5.7%) and methyl syringate (3.0-5.7%; 2.2-4.1%). The composition of the volatiles and semi-volatiles in the obtained extracts suggests that sulla honey is quite distinctive relative to the other honeys that have been chemically studied by GC/MS, but no specific markers of the honey botanical origin were found.

Composition of Sulla (Hedysarum coronarium L. Honey Solvent Extractives Determined by GC/MS: Norisoprenoids and Other Volatile Organic Compounds

Directory of Open Access Journals (Sweden)

Dragan Bubalo

2010-09-01

Full Text Available Samples of unifloral sulla (Hedysarum coronarum L. honey from Sardinia (Italy were analysed. To investigate the chemical composition of the honey volatiles two solvent systems were used for ultrasonic solvent extraction (USE: 1 a 1:2 (v/v pentane and diethyl ether mixture and 2 dichloromethane. All the extracts were analysed by GC and GC/MS. These procedures have permitted the identification of 56 compounds that include norisoprenoids, benzene derivatives, aliphatic compounds and Maillard reaction products. Norisoprenoids were the major compounds in both extracts, dominated by vomifoliol (5.3-11.2%; 9.6-14.0% followed by minor percentages of other norisoprenoids such as α-isophorone, 4-ketoisophorone, 3-oxo-α-ionol or 3-oxo-α-ionone. Other abundant single compounds in the extracts were 3-hydroxy-4-phenylbutan-2-one (0.8-5.4%; 0.6-5.7% and methyl syringate (3.0-5.7%; 2.2-4.1%. The composition of the volatiles and semi-volatiles in the obtained extracts suggests that sulla honey is quite distinctive relative to the other honeys that have been chemically studied by GC/MS, but no specific markers of the honey botanical origin were found.

Constraining the Volatile Regime of Primitive Somma-Vesuvius Magmas Based on the Compositions of Phenocrysts and Melt Inclusions

Science.gov (United States)

Danyushevsky, L. V.; Esposito, R.; De Vivo, B.; Redi, D.; Lima, A.; Bodnar, R. J.; Gurenko, A.

2017-12-01

The volcanic complex of Mt. Somma-Vesuvius is located in the Campanian Plain on east of Naples. We present the results of a mineralogical and melt inclusion studies of primitive volcanic products erupted during the last 2 magmatic cycles of Soma-Vesuvius, aimed at better understanding the volatile fluxes and eruptive behaviour of the volcano. Our results suggest that despite large differences in the compositions of the erupted magmas (from olivine-bearing basaltic lavas to leucite-bearing phonolites) and the eruption style (from plinian to strombolian), there was very little change in the nature of the parental magmas. Melt inclusions in olivine phenocrysts in all volcanic products and styles reveal the highest volatile contents in the most magnesian, early formed crystals (Fo90; H2O 4-5 wt%; CO2 3,000-4,000 ppm), decreasing to near 0 levels of concentrations in olivine Fo70. Major and trace element compositions of the clinopyroxene phenocrysts (Mg#92-70) also suggest a similar parental magma composition and similar liquid lines of decent for all Somma-Vesuvius eruptions. Our results are best explained by a model which relates the eruption style to the intensity of melt supply under the volcano. High intensity plinian eruptions occur after a prolonged repose time, whereas strombolian eruptions occur during periods of more frequent volcanic activity [1]. We will also discuss possible implications for the role of carbonate assimilation during magma evolution of Somma-Vesuvius and for total volatile budget of the SOmma-Vesuvius eruptions. [1] [42] Lima, A., Danyushevsky, L.V., De Vivo, B. and Fedele, L. 2003: A model for the evolution of the Mt. Somma-Vesuvius magmatic system based on fluid and melt inclusion investigations. In: Melt Inclusions in volcanic systems: Methods, applications and Problems (B. De Vivo & R.J. Bodnar, Eds), Series: Developments in Volcanology. No. 5 Elsevier, Amsterdam, 227-251

A dynamic two-dimensional system for measuring volatile organic compound volatilization and movement in soils.

Science.gov (United States)

Allaire, S E; Yates, S R; Ernst, F F; Gan, J

2002-01-01

There is an important need to develop instrumentation that allows better understanding of atmospheric emission of toxic volatile compounds associated with soil management. For this purpose, chemical movement and distribution in the soil profile should be simultaneously monitored with its volatilization. A two-dimensional rectangular soil column was constructed and a dynamic sequential volatilization flux chamber was attached to the top of the column. The flux chamber was connected through a manifold valve to a gas chromatograph (GC) for real-time concentration measurement. Gas distribution in the soil profile was sampled with gas-tight syringes at selected times and analyzed with a GC. A pressure transducer was connected to a scanivalve to automatically measure the pressure distribution in the gas phase of the soil profile. The system application was demonstrated by packing the column with a sandy loam in a symmetrical bed-furrow system. A 5-h furrow irrigation was started 24 h after the injection of a soil fumigant, propargyl bromide (3-bromo-1-propyne; 3BP). The experience showed the importance of measuring lateral volatilization variability, pressure distribution in the gas phase, chemical distribution between the different phases (liquid, gas, and sorbed), and the effect of irrigation on the volatilization. Gas movement, volatilization, water infiltration, and distribution of degradation product (Br-) were symmetric around the bed within 10%. The system saves labor cost and time. This versatile system can be modified and used to compare management practices, estimate concentration-time indexes for pest control, study chemical movement, degradation, and emissions, and test mathematical models.

Political institutions and economic volatility

NARCIS (Netherlands)

Klomp, Jeroen; de Haan, Jakob

We examine the effect of political 'institutions' on economic growth volatility, using data from more than 100 countries over the period 1960 to 2005, taking into account various control variables as suggested in previous studies. Our indicator of volatility is the relative standard deviation of the

Analysis of Volatile Components of Varietal English Wines Using Stir Bar Sorptive Extraction/Gas Chromatography-Mass Spectrometry

Directory of Open Access Journals (Sweden)

Darren J. Caven-Quantrill

2017-12-01

Full Text Available Aroma is an important property of wine and it can be influenced significantly by enological practices. The aim of this work was, by use of stir bar sorptive extraction/gas chromatography-mass spectrometry (SBSE/GC-MS, to compare semi-quantitative concentrations of the volatile constituents of stainless steel tank-fermented/matured Huxelrebe, Ortega, Schönburger and Siegerrebe varietal wines from a commercial English vineyard, with corresponding wines produced by oak cask (‘barrel’ fermentation/maturation. Aroma profiles of tank and barrel wines were different, with more volatiles detected and net concentrations being higher in barrel wines. Long chain ethyl carboxylate esters were generally more abundant in barrel wines, whereas acetate esters were generally more prominent in tank wines. By conducting a short (~7 month maturation period in secondhand (third or fourth fill casks, it was possible to make wines with more complex aromas, but without obvious oak aroma.

The predictive content of CBOE crude oil volatility index

Science.gov (United States)

Chen, Hongtao; Liu, Li; Li, Xiaolei

2018-02-01

Volatility forecasting is an important issue in the area of econophysics. The information content of implied volatility for financial return volatility has been well documented in the literature but very few studies focus on oil volatility. In this paper, we show that the CBOE crude oil volatility index (OVX) has predictive ability for spot volatility of WTI and Brent oil returns, from both in-sample and out-of-sample perspectives. Including OVX-based implied volatility in GARCH-type volatility models can improve forecasting accuracy most of time. The predictability from OVX to spot volatility is also found for longer forecasting horizons of 5 days and 20 days. The simple GARCH(1,1) and fractionally integrated GARCH with OVX performs significantly better than the other OVX models and all 6 univariate GARCH-type models without OVX. Robustness test results suggest that OVX provides different information from as short-term interest rate.

PTR-MS analysis of reference and plant-emitted volatile organic compounds

Science.gov (United States)

Maleknia, Simin D.; Bell, Tina L.; Adams, Mark A.

2007-05-01

Proton transfer reaction-mass spectrometry (PTR-MS) was applied to the analysis of a series of volatile organic compounds (VOCs) that emit from various plants. These include a group of alcohols (methanol, ethanol and butanol), carbonyl-containing compounds (acetic acid, acetone and benzaldehyde), isoprene, acetonitrile, tetrahydrofuran (THF), pyrazine, toluene and xylene and a series of terpenes (p-cymene, camphene, 2-carene, limonene, [beta]-myrcene, [alpha]-pinene, [beta]-pinene, [gamma]-tepinene and terpinolene) and oxygen-containing terpenes (1,8-cineole and linalool). These mass spectral data were compared to an electron ionization (EI) database identifying that not all PTR-MS fragments were common to EI. PTR-MS studies of these reference compounds were utilized to identify VOCs emitted from Eucalyptus grandis leaf at a temperature range of 30-100 °C. In addition to protonated molecules (M + H)+, abundant proton-bound dimers or trimers were detected for alcohols, acetone, acetonitrile and THF. Abundant fragment ions attributed to the loss of water from these proton-bound clusters were also observed. The stability of butyl (C4H9+ m/z 57) and acetyl (CH3CO+ m/z 43) fragment ions directed the proton-transfer reactions of butanol and acetic acid. Abundant (M + H)+ ions were detected for pyrazine, THF, toluene and xylene, as well as for all terpenes except those containing oxygen. For linalool and 1,8-cineole, the loss of water generated an abundant fragment ion at m/z 137. PTR-MS fragmentation patterns for terpenes were proposed for m/z 81 (C6H9+), 93 (C7H9+), 95 (C7H11+), 107 (C8H11+), 109 (C8H13+), 119 (C9H11+), 121 (C9H13+) and 137 (loss of water for oxygen-containing terpenes; C10H17+). The relative abundances of (M + H)+ and fragments for all terpenes (except linalool) were dependent on the drift tube voltage and the optimum voltage for detection of molecular ions was different for various terpenes.

Oil Volatility Risk and Expected Stock Returns

DEFF Research Database (Denmark)

Christoffersen, Peter; Pan, Xuhui (Nick)

return between the quintile of stocks with low exposure and high exposure to oil volatility is significant at 0.66% per month, and oil volatility risk carries a significant risk premium of -0.60% per month. In the post-financialization period, oil volatility risk is strongly related with various measures...

Understanding Interest Rate Volatility

DEFF Research Database (Denmark)

Volker, Desi

This thesis is the result of my Ph.D. studies at the Department of Finance of the Copenhagen Business School. It consists of three essays covering topics related to the term structure of interest rates, monetary policy and interest rate volatility. The rst essay, \\Monetary Policy Uncertainty...... and Interest Rates", examines the role of monetary policy uncertainty on the term structure of interest rates. The second essay, \\A Regime-Switching A ne Term Structure Model with Stochastic Volatility" (co-authored with Sebastian Fux), investigates the ability of the class of regime switching models...... with and without stochastic volatility to capture the main stylized features of U.S. interest rates. The third essay, \\Variance Risk Premia in the Interest Rate Swap Market", investigates the time-series and cross-sectional properties of the compensation demanded for holding interest rate variance risk. The essays...

Equity Volatility and Corporate Bond Yields

OpenAIRE

John Y. Campbell; Glen B. Taksler

2002-01-01

This paper explores the effect of equity volatility on corporate bond yields. Panel data for the late 1990s show that idiosyncratic firm-level volatility can explain as much cross-sectional variation in yields as can credit ratings. This finding, together with the upward trend in idiosyncratic equity volatility documented by Campbell, Lettau, Malkiel, and Xu (2001), helps to explain recent increases in corporate bond yields. The definitive version is available at www.blackwell-synergy.com.

Permanent and transitory oil volatility and aggregate investment in Malaysia

International Nuclear Information System (INIS)

Ibrahim, Mansor H.; Ahmed, Huson Joher Ali

2014-01-01

This paper investigates the relation between aggregate investment and oil volatility and its permanent and transitory components for a developing country, Malaysia. In the paper, the components generalized autoregressive conditional heteroskedasticity (CGARCH) model is utilized to decompose conditional oil volatility into permanent oil volatility and transitory oil volatility. Respectively reflecting fundamental-driven and random shifts in oil volatility, they are expected to exert differential effects on aggregate investment. Adopting a vector autoregression (VAR) framework to allow feedback effects between aggregate investment and its determinants, the paper documents evidence supporting the adverse effects of conditional oil volatility, permanent oil volatility and transitory oil volatility on aggregate investment and real output. Interestingly, contrary to the findings for the developed markets (US and OECD), the real effects of permanent oil volatility tend to be stronger. These findings are reasonably robust to variable specification and measurements in the VAR system. Hence, there is an indication that heightened oil volatility accounts for the slumps in Malaysia's aggregate investment after the Asian financial crisis. - Highlights: • Examines the role of oil volatility in Malaysia's aggregate investment. • Makes distinction between permanent and temporary volatility using CGARCH. • Both volatility components depress investment. • Permanent volatility has larger adverse effects. • Results are robust to alternative model specifications

Firm-level volatility and exports

NARCIS (Netherlands)

Vannoorenberghe, G.C.L.

2012-01-01

This paper shows that the share of exports in the total sales of a firm has a positive and substantial impact on the volatility of its sales. Decomposing the volatility of sales of exporters between their domestic and export markets, I show using an identification strategy based on a firm-specific

Modeling and forecasting petroleum futures volatility

International Nuclear Information System (INIS)

Sadorsky, Perry

2006-01-01

Forecasts of oil price volatility are important inputs into macroeconometric models, financial market risk assessment calculations like value at risk, and option pricing formulas for futures contracts. This paper uses several different univariate and multivariate statistical models to estimate forecasts of daily volatility in petroleum futures price returns. The out-of-sample forecasts are evaluated using forecast accuracy tests and market timing tests. The TGARCH model fits well for heating oil and natural gas volatility and the GARCH model fits well for crude oil and unleaded gasoline volatility. Simple moving average models seem to fit well in some cases provided the correct order is chosen. Despite the increased complexity, models like state space, vector autoregression and bivariate GARCH do not perform as well as the single equation GARCH model. Most models out perform a random walk and there is evidence of market timing. Parametric and non-parametric value at risk measures are calculated and compared. Non-parametric models outperform the parametric models in terms of number of exceedences in backtests. These results are useful for anyone needing forecasts of petroleum futures volatility. (author)

Drug interactions: volatile anesthetics and opioids.

Science.gov (United States)

Glass, P S; Gan, T J; Howell, S; Ginsberg, B

1997-09-01

Multiple drugs are used to provide anesthesia. Volatile anesthetics are commonly combined with opioids. Several studies have demonstrated that small doses of opioid (i.e., within the analgesic range) result in a marked reduction in minimum alveolar concentration (MAC) of the volatile anesthetic that will prevent purposeful movement in 50% of patients at skin incision). Further increases in opioid dose provide only a further small reduction in MAC. Thus, a ceiling effect of the opioid is observed at a MAC value of the volatile anesthetic equal to its MAC awake. Recovery from anesthesia when an opioid is combined with a volatile anesthetic is dependent on the rate of decrease of both drugs to their respective concentrations that are associated with adequate spontaneous ventilation and awakening. Through an understanding of the pharmacodynamic interaction of volatile anesthetics with opioids and the pharmacokinetic processes responsible for the recovery from drug effect, optimal dosing schemes can thus be developed. A review of these pharmacodynamic and pharmacokinetic principles that will allow clinicians to administer drugs to provide a more optimal anesthetic is provided.

Inflation, its Volatility and the Inflation-Growth Tradeoff in India

OpenAIRE

Raghbendra Jha; Varsha S. Kulkarni

2013-01-01

This paper amends the New Keynesian Phillips curve model to include inflation volatility. It provides results on the determinants of inflation volatility and expected inflation volatility for OLS and ARDL(1,1) models and for change in inflation volatility and change in expected inflation volatility using ECM models. Output gap affects change in expected inflation volatility alone (in the ECM model) and not in the other models. Major determinants of inflation volatility and expected inflation ...

Contribution of early impact events to metal-silicate separation, thermal annealing, and volatile redistribution: Evidence in the Pułtusk H chondrite

Science.gov (United States)

Krzesińska, Agata M.

2017-11-01

Three-dimensional X-ray tomographic reconstructions and petrologic studies reveal voluminous accumulations of metal in Pułtusk H chondrite. At the contact of these accumulations, the chondritic rock is enriched in troilite. The rock contains plagioclase-rich bands, with textures suggesting crystallization from melt. Unusually large phosphates are associated with the plagioclase and consist of assemblages of merrillite, and fluorapatite and chlorapatite. The metal accumulations were formed by impact melting, rapid segregation of metal-sulfide melt and the incorporation of this melt into the fractured crater basement. The impact most likely occurred in the early evolution of the H chondrite parent body, when post-impact heat overlapped with radiogenic heat. This enabled slow cooling and separation of the metallic melt into metal-rich and sulfide-rich fractions. This led to recrystallization of chondritic rock in contact with the metal accumulations and the crystallization of shock melts. Phosphorus was liberated from the metal and subsumed by the silicate shock melt, owing to oxidative conditions upon slow cooling. The melt was also a host for volatiles. Upon further cooling, phosphorus reacted with silicates leading to the formation of merrillite, while volatiles partitioned into the residual halogen-rich, dry fluid. In the late stages, the fluid altered merrillite to patchy Cl/F-apatite. The above sequence of alterations demonstrates that impact during the early evolution of chondritic parent bodies might have contributed to local metal segregation and silicate melting. In addition, postshock conditions supported secondary processes: compositional/textural equilibration, redistribution of volatiles, and fluid alterations.

Estimation of volatility of selected oil production projects

International Nuclear Information System (INIS)

Costa Lima, Gabriel A.; Suslick, Saul B.

2006-01-01

In oil project valuation and investment decision-making, volatility is a key parameter, but it is difficult to estimate. From a traditional investment viewpoint, volatility reduces project value because it increases its discount rate via a higher risk premium. Contrarily, according to the real-option pricing theory, volatility may aggregate value to the project, since the downside potential is limited whereas the upside is theoretically unbounded. However, the estimation of project volatility is very complicated since there is not a historical series of project values. In such cases, many analysts assume that oil price volatility is equal to that of project. In order to overcome such problems, in this paper an alternative numerical method based on present value of future cash flows and Monte Carlo simulation is proposed to estimate the volatility of projects. This method is applied to estimate the volatility of 12 deep-water offshore oil projects considering that oil price will evolve according to one of two stochastic processes: Geometric Brownian Motion and Mean-Reverting Motion. Results indicate that the volatility of commodity usually undervalue that of project. For the set of offshore projects analyzed in this paper, project volatility is at least 79% higher than that of oil prices and increases dramatically in those cases of high capital expenditures and low price. (author)

Production Function of Outgassed Volatiles on Mercury: Implications for Polar Volatiles on Mercury and the Moon

Science.gov (United States)

Deutsch, A. N.; Head, J. W.

2018-05-01

We are interested in the flux of volatiles delivered to the polar regions of Mercury and the Moon through time. We integrate the production functions for volatile delivery from impacts, solar wind, and volcanism, which we focus on initially.

Volatile and non-volatile compounds in green tea affected in harvesting time and their correlation to consumer preference.

Science.gov (United States)

Kim, Youngmok; Lee, Kwang-Geun; Kim, Mina K

2016-10-01

Current study was designed to find out how tea harvesting time affects the volatile and non-volatile compounds profiles of green tea. In addition, correlation of instrumental volatile and non-volatile compounds analyses to consumer perception were analyzed. Overall, earlier harvested green tea had stronger antioxidant capacity (~61.0%) due to the polyphenolic compounds from catechin (23,164 mg/L), in comparison to later harvested green teas (11,961 mg/L). However, high catechin content in green tea influenced negatively the consumer likings of green tea, due to high bitterness (27.6%) and astringency (13.4%). Volatile compounds drive consumer liking of green tea products were also identified, that included linalool, 2,3-methyl butanal, 2-heptanone, (E,E)-3,5-Octadien-2-one. Finding from current study are useful for green tea industry as it provide the difference in physiochemical properties of green tea harvested at different intervals.

On the non-causal link between volatility and growth

DEFF Research Database (Denmark)

Posch, Olaf; Wälde, Klaus

A model highlighting the endogeneity of both volatility and growth is presented. Volatility and growth are therefore correlated but there is no causal link from volatility to growth. This joint endogeneity is illustrated by working out the effects through which economies with different tax levels...... di er both in their volatility and growth. Using a continuous-time DSGE model with plausible parametric restrictions, we obtain closedform measures of macro volatility based on cyclical components and output growth rates. Given our results, empirical volatility-growth analysis should include controls...

Volatilization of iodine from soils and plants

International Nuclear Information System (INIS)

Wildung, R.E.; Cataldo, D.A.; Garland, T.R.

1985-04-01

Elevated levels of 129 I, a long-lived fission product, are present in the environment as a result of nuclear weapons testing and fuel reprocessing. To aid in understanding the anomalous behavior of this element, relative to natural I ( 127 I), in the vicinity of nuclear fuel reprocessing plants, preliminary laboratory-growth chamber studies were undertaken to examine the possible formation of volatile inorganic and organic I species in soil and plant systems. Inorganic 129 I added to soil was volatilized from both the soil and plant during plant growth, at average ratios of 2 x 10 -3 %/day soil and 9 x 10 -3 %/day foliage, respectively. Volatilization rates from soil were an order of magnitude less in the absence of growing roots. Less than 2% of soil or plant volatiles was subsequently retained by plant canopies. Volatile I, chemically characterized by selective sorption methods, consisted principally of alkyl iodides formed by both soil and plant processes. However, plants and soils containing actively growing roots produced a larger fraction of volatile inorganic I than soil alone. 14 refs., 1 fig., 3 tabs

Identification of leaf volatiles from olive (Olea europaea) and their possible role in the ovipositional preferences of olive fly, Bactrocera oleae (Rossi) (Diptera: Tephritidae).

Science.gov (United States)

Malheiro, Ricardo; Casal, Susana; Cunha, Sara C; Baptista, Paula; Pereira, José Alberto

2016-01-01

The olive fly, Bactrocera oleae (Rossi), is a monophagous pest that displays an oviposition preference among cultivars of olive (Olea europaea L.). To clarify the oviposition preference, the olive leaf volatiles of three olive cultivars (Cobrançosa, Madural and Verdeal Transmontana) were assessed by headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC/MS) at six different periods of olive fruit maturation and degrees of infestation. A total of 39 volatiles were identified, mainly esters and alcohols, with a minor percentage of aldehydes, ketones and terpenic compounds, including sesquiterpenes. At sampling dates with higher degrees of infestation, cv. Cobrançosa had, simultaneously, significantly lower infestation degrees and higher volatile amounts than the other two cultivars, with a probable deterrent effect for oviposition. The green leaf volatiles (GLVs) (Z)-3-hexen-1-ol and (Z)-3-hexen-1-ol acetate) were the main compounds identified in all cultivars, together with toluene. The abundance of GLVs decreased significantly throughout maturation, without significant differences among cultivars, while toluene showed a general increase and positive correlation with olive fly infestation levels. The results obtained could broaden our understanding of the roles of various types and amounts of olive volatiles in the environment, especially in olive fly host selection and cultivar preference. Copyright © 2015 Elsevier Ltd. All rights reserved.

Constraining the volatile budget of the lunar interior

Science.gov (United States)

Potts, N. J.; Bromiley, G. D.

2017-12-01

Measurements of volatiles (F, Cl, S, H2O) in a range of lunar samples confirm the presence of volatile material in lunar magmas. It remains unknown, however, where this volatile material is stored and when it was delivered to the Moon. On Earth, point defects within mantle olivine, and its high-pressure polymorphs, are thought to be the largest reservoir of volatile material. However, as volatiles have been cycled into and out of the Earth's mantle throughout geological time, via subduction and volcanism, this masks any original volatile signatures. As the Moon has no plate tectonics, it is expected that any volatile material present in the deep lunar interior would have been inherited during accretion and differentiation, providing insight into the delivery of volatiles to the early Earth-Moon system. Our aim was, therefore, to test the volatile storage capacity of the deep lunar mantle and determine mineral/melt partitioning for key volatiles. Experiments were performed in a primitive lunar mantle composition and run at relevant T, P, and at fO2 below the IW buffer. Experiments replicated the initial stages of LMO solidification with either olivine + melt, olivine + pyroxene + melt, or pyroxene + melt as the only phases present. Mineral-melt partition coefficients (Dx) derived for volatile material (F, Cl, S, H2O) vary significantly compared to those derived for terrestrial conditions. An order of magnitude more H2O was found to partition into lunar olivine compared to the terrestrial upper mantle. DF derived for lunar olivine are comparable to the highest terrestrial derived values whilst no Cl was found to partition into lunar olivine under these conditions. Furthermore, an inverse trend between DF and DOH hints towards coupled-substitution mechanisms between H and F under low-fO2/lunar bulk composition. These results suggest that if volatile material was present in the LMO a significant proportion could be partitioned into the lower lunar mantle. The

Labour Demand and Exchange Rate Volatility

OpenAIRE

Udo Broll; Sabine Hansen

2004-01-01

The purpose of this paper is to assess under what conditions exchange rate volatility exerts a positive effect on a firm's labour demand. As the exchange rate volatility increases, so does the value of the export option provided the firm under study is flexible. Flexibility is important because it gives the firm option value. Higher volatility increases the potential gains from trade and may increase the demand for labour. This may explain part of the mixed empirical findings regarding the ef...

Elemental volatility of HT-9 fusion reactor alloy

International Nuclear Information System (INIS)

Henslee, S.P.; Neilson, R.M. Jr.

1985-01-01

The volatility of elemental constituents from HT-9, a ferritic steel, proposed for fusion reactor structures, was investigated. Tests were conducted in flowing air at temperatures from 800 to 1200 0 C for durations of 1 to 20 h. Elemental volatility was calculated in terms of the weight fraction of the element volatilized from the initial alloy; molybdenum, manganese, and nickel were the primary constituents volatilized. Comparisons with elemental volatilities observed for another candidate fusion reactor materials. Primary Candidate Alloy (PCA), an austenitic stainless steel, indicate significant differences between the volatilities of these steels that may impact fusion reactor safety analysis and alloy selection. Scanning electron microscopy and energy dispersive spectrometry were used to investigate the oxide layers formed on HT-9 and to measure elemental contents within these layers

Estimation and prediction under local volatility jump-diffusion model

Science.gov (United States)

Kim, Namhyoung; Lee, Younhee

2018-02-01

Volatility is an important factor in operating a company and managing risk. In the portfolio optimization and risk hedging using the option, the value of the option is evaluated using the volatility model. Various attempts have been made to predict option value. Recent studies have shown that stochastic volatility models and jump-diffusion models reflect stock price movements accurately. However, these models have practical limitations. Combining them with the local volatility model, which is widely used among practitioners, may lead to better performance. In this study, we propose a more effective and efficient method of estimating option prices by combining the local volatility model with the jump-diffusion model and apply it using both artificial and actual market data to evaluate its performance. The calibration process for estimating the jump parameters and local volatility surfaces is divided into three stages. We apply the local volatility model, stochastic volatility model, and local volatility jump-diffusion model estimated by the proposed method to KOSPI 200 index option pricing. The proposed method displays good estimation and prediction performance.

Oak (Quercus frainetto Ten. Honeydew Honey—Approach to Screening of Volatile Organic Composition and Antioxidant Capacity (DPPH and FRAP Assay

Directory of Open Access Journals (Sweden)

Igor Jerković

2010-05-01

Full Text Available Two samples of oak honeydew honey were investigated. Headspace solid-phase microextraction (HS-SPME combined with GC and GC/MS enabled identification of the most volatile organic headspace compounds being dominated by terpenes(mainly cis- and trans-linalool oxides. The volatile and less-volatile organic composition of the samples was obtained by ultrasonic assisted extraction (USE with two solvents (1:2 (v/v pentane -diethyl ether mixture and dichloromethane followed by GC and GC/MS analysis. Shikimic pathway derivatives are of particular interest with respect to the botanical origin of honey and the most abundant was phenylacetic acid (up to 16.4%. Antiradical activity (DPPH assay of the honeydew samples was 4.5 and 5.1 mmol TEAC/kg. Ultrasonic solvent extracts showed several dozen times higher antiradical capacity in comparison to the honeydew. Antioxidant capacity (FRAP assay of honeydew samples was 4.8 and 16.1 mmol Fe2+/kg, while the solvent mixture extracts showed antioxidant activity of 374.5 and 955.9 Fe2+/kg, respectively, and the dichloromethane extracts 127.3 and 101.5 mmol Fe2+/kg.

Production of volatiles by the red seaweed Gelidium arbuscula (Rhodophyta): emission of ethylene and dimethyl sulfide.

Science.gov (United States)

Garcia-Jimenez, Pilar; Brito-Romano, Olegario; Robaina, Rafael R

2013-08-01

The effects of different light conditions and exogenous ethylene on the emission of volatile compounds from the alga Gelidium arbuscula Bory de Saint-Vincent were studied. Special emphasis was placed on the possibility that the emission of ethylene and dimethyl sulfide (DMS) are related through the action of dimethylsulfoniopropionate (DMSP) lyase. The conversion of DMSP to DMS and acrylate, which is catalyzed by DMSP lyase, can indirectly support the synthesis of ethylene through the transformation of acrylate to ethylene. After mimicking the desiccation of G. arbuscula thalli experienced during low tides, the volatile compounds emitted were trapped in the headspace of 2 mL glass vials for 1 h. Two methods based on gas chromatography/mass spectrometry revealed that the range of organic volatile compounds released was affected by abiotic factors, such as the availability and spectral quality of light, salinity, and exogenous ethylene. Amines and methyl alkyl compounds were produced after exposure to white light and darkness but not after exposure to exogenous ethylene or red light. Volatiles potentially associated with the oxidation of fatty acids, such as alkenes and low-molecular-weight oxygenated compounds, accumu-lated after exposure to exogenous ethylene and red light. Ethylene was produced in all treatments, especially after exposure to exogenous ethylene. Levels of DMS, the most abundant sulfur-compound that was emitted in all of the conditions tested, did not increase after incubation with ethylene. Thus, although DMSP lyase is active in G. arbuscula, it is unlikely to contribute to ethylene synthesis. The generation of ethylene and DMS do not appear to be coordinated in G. arbuscula. © 2013 Phycological Society of America.

Exposure to Anacardiaceae Volatile Oils and Their Constituents Induces Lipid Peroxidation within Food-Borne Bacteria Cells

Directory of Open Access Journals (Sweden)

Ricardo M. Montanari

2012-08-01

Full Text Available The chemical composition of the volatile oils from five Anacardiaceae species and their activities against Gram positive and negative bacteria were assessed. The peroxidative damage within bacterial cell membranes was determined through the breakdown product malondialdehyde (MDA. The major constituents in Anacardium humile leaves oil were (E-caryophyllene (31.0% and α-pinene (22.0%, and in Anacardium occidentale oil they were (E-caryophyllene (15.4% and germacrene-D (11.5%. Volatile oil from Astronium fraxinifolium leaves were dominated by (E-β-ocimene (44.1% and α-terpinolene (15.2%, whilst the oil from Myracrodruon urundeuva contained an abundance of δ-3-carene (78.8%. However, Schinus terebinthifolius leaves oil collected in March and July presented different chemical compositions. The oils from all species, except the one from A. occidentale, exhibited varying levels of antibacterial activity against Staphylococcus aureus, Bacillus cereus and Escherichia coli. Oil extracted in July from S. terebinthifolius was more active against all bacterial strains than the corresponding oil extracted in March. The high antibacterial activity of the M. urundeuva oil could be ascribed to its high δ-3-carene content. The amounts of MDA generated within bacterial cells indicate that the volatile oils induce lipid peroxidation. The results suggest that one putative mechanism of antibacterial action of these volatile oils is pro-oxidant damage within bacterial cell membrane explaining in part their preservative properties.

Aspects of volatility targeting for South African equity investors

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Bhekinkosi Khuzwayo

2014-11-01

Full Text Available We consider so-called volatility targeting strategies in the South African equity market. These strategies are aimed at keeping the volatility of a portfolio consisting of a risky asset, typically an equity index, and cash fixed. This is done by changing the allocation of the assets based on an indicator of the future volatility of the risky asset. We use the three month rolling implied volatility as an indicator of future volatility to influence our asset allocation. We compare investments based on different volatility targets to the performance of bonds, equities, property as well as the Absolute Return peer mean. We examine risk and return characteristics of the volatility targeting strategy as compared to different asset classes.

High salinity volatile phases in magmatic Ni-Cu-platinum group element deposits

Science.gov (United States)

Hanley, J. J.; Mungall, J. E.

2004-12-01

The role of "deuteric" fluids (exsolved magmatic volatile phases) in the development of Ni-Cu-PGE (platinum group element) deposits in mafic-ultramafic igneous systems is poorly understood. Although considerable field evidence demonstrates unambiguously that fluids modified most large primary Ni-Cu-PGE concentrations, models which hypothesize that fluids alone were largely responsible for the economic concentration of the base and precious metals are not widely accepted. Determination of the trace element composition of magmatic volatile phases in such ore-forming systems can offer considerable insight into the origin of potentially mineralizing fluids in such igneous environments. Laser ablation ICP-MS microanalysis allows researchers to confirm the original metal budget of magmatic volatile phases and quantify the behavior of trace ore metals in the fluid phase in the absence of well-constrained theoretical or experimental predictions of ore metal solubility. In this study, we present new evidence from major deposits (Sudbury, Ontario, Canada; Stillwater Complex, Montana, U.S.A.) that compositionally distinct magmatic brines and halide melt phases were exsolved from crystallizing residual silicate melt and trapped within high-T fluid conduits now comprised of evolved rock compositions (albite-quartz graphic granite, orthoclase-quartz granophyre). Petrographic evidence demonstrates that brines and halide melts coexisted with immiscible carbonic phases at the time of entrapment (light aliphatic hydrocarbons, CO2). Brine and halide melt inclusions are rich in Na, Fe, Mn, K, Pb, Zn, Ba, Sr, Al and Cl, and homogenize by either halite dissolution at high T ( ˜450-700° C) or by melting of the salt phase (700-800° C). LA-ICPMS analyses of single inclusions demonstrate that high salinity volatile phases contained abundant base metals (Cu, Fe, Sn, Bi) and precious metals (Pt, Pd, Au, Ag) at the time of entrapment. Notably, precious metal concentrations in the inclusions

Volatility Forecast in Crises and Expansions

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Sergii Pypko

2015-08-01

Full Text Available We build a discrete-time non-linear model for volatility forecasting purposes. This model belongs to the class of threshold-autoregressive models, where changes in regimes are governed by past returns. The ability to capture changes in volatility regimes and using more accurate volatility measures allow outperforming other benchmark models, such as linear heterogeneous autoregressive model and GARCH specifications. Finally, we show how to derive closed-form expression for multiple-step-ahead forecasting by exploiting information about the conditional distribution of returns.

Multifractal analysis of implied volatility in index options

Science.gov (United States)

Oh, GabJin

2014-06-01

In this paper, we analyze the statistical and the non-linear properties of the log-variations in implied volatility for the CAC40, DAX and S& P500 daily index options. The price of an index option is generally represented by its implied volatility surface, including its smile and skew properties. We utilize a Lévy process model as the underlying asset to deepen our understanding of the intrinsic property of the implied volatility in the index options and estimate the implied volatility surface. We find that the options pricing models with the exponential Lévy model can reproduce the smile or sneer features of the implied volatility that are observed in real options markets. We study the variation in the implied volatility for at-the-money index call and put options, and we find that the distribution function follows a power-law distribution with an exponent of 3.5 ≤ γ ≤ 4.5. Especially, the variation in the implied volatility exhibits multifractal spectral characteristics, and the global financial crisis has influenced the complexity of the option markets.

Detecting instability in the volatility of carbon prices

Energy Technology Data Exchange (ETDEWEB)

Chevallier, Julien [Univ. Paris Dauphine (France)

2011-01-15

This article investigates the presence of outliers in the volatility of carbon prices. We compute three different measures of volatility for European Union Allowances, based on daily data (EGARCH model), option prices (implied volatility), and intraday data (realized volatility). Based on the methodology developed by Zeileis et al. (2003) and Zeileis (2006), we detect instability in the volatility of carbon prices based on two kinds of tests: retrospective tests (OLS-/Recursive-based CUSUM processes, F-statistics, and residual sum of squares), and forward-looking tests (by monitoring structural changes recursively or with moving estimates). We show evidence of strong shifts mainly for the EGARCH and IV models during the time period. Overall, we suggest that yearly compliance events, and growing uncertainties in post-Kyoto international agreements, may explain the instability in the volatility of carbon prices. (author)

Characterization of volatile substances in apples from Rosaceae family by headspace solid-phase microextraction followed by GC-qMS.

Science.gov (United States)

Ferreira, Liseth; Perestrelo, Rosa; Caldeira, Michael; Câmara, José S

2009-06-01

The volatile composition of different apple varieties of Malus domestica Borkh. species from different geographic regions at Madeira Islands, namely Ponta do Pargo (PP), Porto Santo (PS), and Santo da Serra (SS) was established by headspace solid-phase microextraction (HS-SPME) procedure followed by GC-MS (GC-qMS) analysis. Significant parameters affecting sorption process such as fiber coating, extraction temperature, extraction time, sample amount, dilution factor, ionic strength, and desorption time, were optimized and discussed. The SPME fiber coated with 50/30 microm divinylbenzene/carboxen/PDMS (DVB/CAR/PDMS) afforded highest extraction efficiency of volatile compounds, providing the best sensitivity for the target volatiles, particularly when the samples were extracted at 50 degrees C for 30 min with constant magnetic stirring. A qualitative and semi-quantitative analysis between the investigated apple species has been established. It was possible to identify about 100 of volatile compounds among pulp (46, 45, and 39), peel (64, 60, and 64), and entire fruit (65, 43, and 50) in PP, PS, and SS apples, respectively. Ethyl esters, terpenes, and higher alcohols were found to be the most representative volatiles. Alpha-farnesene, hexan-1-ol and hexyl 2-methylbutyrate were the compounds found in the volatile profile of studied apples with the largest GC area, representing, on average, 24.71, 14.06, and 10.80% of the total volatile fraction from PP, PS, and SS apples. In PP entire apple, the most abundant compounds identified were alpha-farnesene (30.49%), the unknown compound m/z (69, 101, 157) (21.82%) and hexyl acetate (6.57%). Regarding PS entire apple the major compounds were alpha-farnesene (16.87%), estragole (15.43%), hexan-1-ol (10.94), and E-2-hexenal (10.67). Alpha-farnesene (30.3%), hexan-1-ol (18.90%), 2-methylbutanoic acid (4.7%), and pentan-1-ol (4.6%) were also found as SS entire apple volatiles present in a higher relative content. Principal

Microbiology, biochemistry, and volatile composition of Tulum cheese ripened in goat's skin or plastic bags.

Science.gov (United States)

Hayaloglu, A A; Cakmakci, S; Brechany, E Y; Deegan, K C; McSweeney, P L H

2007-03-01

Tulum cheeses were manufactured from raw ewe's milk and ripened in goat's skin bags (tulums) or plastic containers to understand the effect of ripening container on the chemical composition, biochemistry, microbiology, and volatile composition of Tulum cheeses during 150 d of ripening. Chemical compositions of the cheeses ripened in tulums were significantly different and the moisture contents decreased rapidly in those cheeses because of the porous structure of the tulum. Higher microbial counts were detected in the cheeses ripened in plastic than in cheeses ripened in tulums. Differences in nitrogenous compounds and total free AA of the cheeses were not significant. Total concentrations of free AA in cheeses increased with age and Glu, Ala, Val, Leu, and Phe were the most abundant AA in the cheeses. Urea-PAGE of pH 4.6-insoluble fractions of the cheeses during ripening showed similar degradation patterns in all cheeses. Peptide profiles by reversed-phase HPLC of pH 4.6- and ethanol-soluble or ethanol-insoluble fractions of the cheeses revealed only minor differences in the concentrations of some peptides among the cheeses; however, age-related changes in peptide concentrations were significantly different among the cheeses. Cheeses were analyzed at 90 d of ripening for volatile compounds by solid-phase microextraction gas chromatography-mass spectrometry. One hundred volatile components were identified, including 11 acids, 16 esters, 12 methyl ketones, 7 aldehydes, 22 alcohols, 7 sulfur compounds, 6 terpenes, and 19 miscellaneous compounds. The main components were short-chain fatty acids, 2-butanone, diacetyl, and primary alcohols. Quantitative differences in several volatile compounds were evident among the cheeses. Cheeses ripened in tulums or plastic had similar aroma patterns, but the concentrations of some components were different.

CAM Stochastic Volatility Model for Option Pricing

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Wanwan Huang

2016-01-01

Full Text Available The coupled additive and multiplicative (CAM noises model is a stochastic volatility model for derivative pricing. Unlike the other stochastic volatility models in the literature, the CAM model uses two Brownian motions, one multiplicative and one additive, to model the volatility process. We provide empirical evidence that suggests a nontrivial relationship between the kurtosis and skewness of asset prices and that the CAM model is able to capture this relationship, whereas the traditional stochastic volatility models cannot. We introduce a control variate method and Monte Carlo estimators for some of the sensitivities (Greeks of the model. We also derive an approximation for the characteristic function of the model.

[Solidification of volatile oil with graphene oxide].

Science.gov (United States)

Yan, Hong-Mei; Jia, Xiao-Bin; Zhang, Zhen-Hai; Sun, E; Xu, Yi-Hao

2015-02-01

To evaluate the properties of solidifying volatile oil with graphene oxide, clove oil and zedoary turmeric oil were solidified by graphene oxide. The amount of graphene oxide was optimized with the eugenol yield and curcumol yield as criteria. Curing powder was characterized by differential scanning calorimetry (DSC) and scanning electron microscopy (SEM). The effects of graphene oxide on dissolution in vitro and thermal stability of active components were studied. The optimum solidification ratio of graphene oxide to volatile oil was 1:1. Dissolution rate of active components had rare influence while their thermal stability improved after volatile oil was solidified. Solidifying herbal volatile oil with graphene oxide deserves further study.

Macroeconomic Volatility and Welfare in Developing Countries

OpenAIRE

Loayza, Norman V.; Rancière, Romain; Servén, Luis; Ventura, Jaume

2007-01-01

Macroeconomic Volatility and Welfare in Developing Countries: An Introduction Norman V. Loayza, Romain Ranciere, Luis Serven, ` and Jaume Ventura Macroeconomic volatility, both a source and a reflection of underdevelopment, is a fundamental concern for developing countries. This article provides a brief overview of the recent literature on macroeconomic volatility in developing countries, highlighting its causes, consequences, and possible remedies. to reduce domestic policy-induced macroecon...

Volatile liquid storage system

International Nuclear Information System (INIS)

Laverman, R.J.; Winters, P.J.; Rinehart, J.K.

1992-01-01

This patent describes a method of collecting and abating emission from a volatile liquid in an above ground storage tank. It comprises the liquid storage tank having a bottom, a vertical cylindrical circular wall having a lower edge portion joined to the bottom, and an external fixed roof, the tank having an internal floating roof floating on a volatile liquid stored in the tank, and air vent means in the tank in communication with a vapor space in the tank constituting at least the space above the floating roof when the floating roof floats on a predetermined maximum volume of volatile liquid in the tank; permitting ambient air; pumping emission laden air from the tank vapor space above the floating roof; and by means of the emissions abatement apparatus eliminating most of the emission from the emissions laden air with formation of a gaseous effluent and then discharging the resulting gaseous effluent to the atmosphere

Decomposing European bond and equity volatility

DEFF Research Database (Denmark)

Christiansen, Charlotte

The paper investigates volatility spillover from US and aggregate European asset markets into European national asset markets. A main contribution is that bond and equity volatilities are analyzed simultaneously. A new model belonging to the "volatilityspillover" family is suggested: The conditio...

The economic value of realized volatility

DEFF Research Database (Denmark)

Christoffersen, Peter; Feunou, Bruno; Jacobs, Kris

2014-01-01

Many studies have documented that daily realized volatility estimates based on intraday returns provide volatility forecasts that are superior to forecasts constructed from daily returns only. We investigate whether these forecasting improvements translate into economic value added. To do so, we ...

Empirical Analysis of Stochastic Volatility Model by Hybrid Monte Carlo Algorithm

International Nuclear Information System (INIS)

Takaishi, Tetsuya

2013-01-01

The stochastic volatility model is one of volatility models which infer latent volatility of asset returns. The Bayesian inference of the stochastic volatility (SV) model is performed by the hybrid Monte Carlo (HMC) algorithm which is superior to other Markov Chain Monte Carlo methods in sampling volatility variables. We perform the HMC simulations of the SV model for two liquid stock returns traded on the Tokyo Stock Exchange and measure the volatilities of those stock returns. Then we calculate the accuracy of the volatility measurement using the realized volatility as a proxy of the true volatility and compare the SV model with the GARCH model which is one of other volatility models. Using the accuracy calculated with the realized volatility we find that empirically the SV model performs better than the GARCH model.

Implications for metal and volatile cycles from the pH of subduction zone fluids

Science.gov (United States)

Galvez, Matthieu E.; Connolly, James A. D.; Manning, Craig E.

2016-11-01

The chemistry of aqueous fluids controls the transport and exchange—the cycles—of metals and volatile elements on Earth. Subduction zones, where oceanic plates sink into the Earth’s interior, are the most important geodynamic setting for this fluid-mediated chemical exchange. Characterizing the ionic speciation and pH of fluids equilibrated with rocks at subduction zone conditions has long been a major challenge in Earth science. Here we report thermodynamic predictions of fluid-rock equilibria that tie together models of the thermal structure, mineralogy and fluid speciation of subduction zones. We find that the pH of fluids in subducted crustal lithologies is confined to a mildly alkaline range, modulated by rock volatile and chlorine contents. Cold subduction typical of the Phanerozoic eon favours the preservation of oxidized carbon in subducting slabs. In contrast, the pH of mantle wedge fluids is very sensitive to minor variations in rock composition. These variations may be caused by intramantle differentiation, or by infiltration of fluids enriched in alkali components extracted from the subducted crust. The sensitivity of pH to soluble elements in low abundance in the host rocks, such as carbon, alkali metals and halogens, illustrates a feedback between the chemistry of the Earth’s atmosphere-ocean system and the speciation of subduction zone fluids via the composition of the seawater-altered oceanic lithosphere. Our findings provide a perspective on the controlling reactions that have coupled metal and volatile cycles in subduction zones for more than 3 billion years7.

Potassium isotope abundances in Australasian tektites and microtektites.

Science.gov (United States)

Herzog, G. F.; O'D. Alexander, C. M.; Berger, E. L.; Delaney, J. S.; Glass, B. P.

2008-10-01

We report electron microprobe determinations of the elemental compositions of 11 Australasian layered tektites and 28 Australasian microtektites; and ion microprobe determinations of the 41K/39K ratios of all 11 tektites and 13 of the microtektites. The elemental compositions agree well with literature values, although the average potassium concentrations measured here for microtektites, 1.1 1.6 wt%, are lower than published average values, 1.9 2.9 wt%. The potassium isotope abundances of the Australasian layered tektites vary little. The average value of δ41K, 0.02 ± 0.12‰ (1σ mean), is indistinguishable from the terrestrial value (= 0 by definition) as represented by our standard, thereby confirming four earlier tektite analyses of Humayun and Koeberl (2004). In agreement with those authors, we conclude that evaporation has significantly altered neither the isotopic nor the elemental composition of Australasian layered tektites for elements less volatile than potassium. Although the average 41K/39K ratio of the microtektites, 1.1 ± 1.7‰ (1σ mean), is also statistically indistinguishable from the value for the standard, the individual ratios vary over a very large range, from -10.6 ± 1.4‰ to +13.8 ± 1.5‰ and at least three of them are significantly different from zero. We interpret these larger variations in terms of the evaporation of isotopically light potassium; condensation of potassium in the vapor plume; partial or complete stirring and quenching of the melts; and the possible uptake of potassium from seawater. That the average 41K/39K ratio of the microtektites equals the terrestrial value suggests that the microtektite-forming system was compositionally closed with respect to potassium and less volatile elements. The possibility remains open that 41K/39K ratios of microtektites vary systematically with location in the strewn field.

Observability of market daily volatility

Science.gov (United States)

Petroni, Filippo; Serva, Maurizio

2016-02-01

We study the price dynamics of 65 stocks from the Dow Jones Composite Average from 1973 to 2014. We show that it is possible to define a Daily Market Volatility σ(t) which is directly observable from data. This quantity is usually indirectly defined by r(t) = σ(t) ω(t) where the r(t) are the daily returns of the market index and the ω(t) are i.i.d. random variables with vanishing average and unitary variance. The relation r(t) = σ(t) ω(t) alone is unable to give an operative definition of the index volatility, which remains unobservable. On the contrary, we show that using the whole information available in the market, the index volatility can be operatively defined and detected.

Stock return, seasonality and asymmetric conditional volatility in steel & iron subsector

Directory of Open Access Journals (Sweden)

V. Chirila

2015-01-01

Full Text Available This paper presents the results obtained following the testing of five hypotheses regarding conditional return and volatility of the most listed European stocks in the steel & iron subsector. The following elements of the stocks are analysed: time variation of volatility, seasonality of return and volatility, relationship between return and volatility and volatility asymmetry. The results obtained confirm for all the analyzed stocks the existence of volatility variation in time, the lack of correlation between return and volatility, the existence of asymmetry phenomenon of volatility and the presence in some stocks of the seasonality effect both for return and volatility.

Bias-reduced estimation of long memory stochastic volatility

DEFF Research Database (Denmark)

Frederiksen, Per; Nielsen, Morten Ørregaard

We propose to use a variant of the local polynomial Whittle estimator to estimate the memory parameter in volatility for long memory stochastic volatility models with potential nonstation- arity in the volatility process. We show that the estimator is asymptotically normal and capable of obtaining...

Volatile-mediated interactions between phylogenetically different soil bacteria

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Paolina eGarbeva

2014-06-01

Full Text Available There is increasing evidence that organic volatiles play an important role in interactions between micro-organisms in the porous soil matrix. Here we report that volatile compounds emitted by different soil bacteria can affect the growth, antibiotic production and gene expression of the soil bacterium Pseudomonas fluorescens Pf0-1. We applied a novel cultivation approach that mimics the natural nutritional heterogeneity in soil in which P. fluorescens grown on nutrient-limited agar was exposed to volatiles produced by 4 phylogenetically different bacterial isolates (Collimonas pratensis, Serratia plymuthica, Paenibacillus sp. and Pedobacter sp. growing in sand containing artificial root exudates. Contrary to our expectation, the produced volatiles stimulated rather than inhibited the growth of P. fluorescens. A genome-wide, microarray-based analysis revealed that volatiles of all 4 bacterial strains affected gene expression of P. fluorescens, but with a different pattern of gene expression for each strain. Based on the annotation of the differently expressed genes, bacterial volatiles appear to induce a chemotactic motility response in P. fluorescens, but also an oxidative stress response. A more detailed study revealed that volatiles produced by C. pratensis triggered, antimicrobial secondary metabolite production in P. fluorescens. Our results indicate that bacterial volatiles can have an important role in communication, trophic - and antagonistic interactions within the soil bacterial community.

Investment timing under hybrid stochastic and local volatility

International Nuclear Information System (INIS)

Kim, Jeong-Hoon; Lee, Min-Ku; Sohn, So Young

2014-01-01

Highlights: • The effects of hybrid stochastic volatility on real option prices are studied. • The stochastic volatility consists of a fast mean-reverting component and a CEV type one. • A fast mean-reverting factor lowers real option prices and investment thresholds. • The increase of elasticity raises real option prices and investment thresholds. • The effects of the addition of a slowly varying factor depend upon the project value. - Abstract: We consider an investment timing problem under a real option model where the instantaneous volatility of the project value is given by a combination of a hidden stochastic process and the project value itself. The stochastic volatility part is given by a function of a fast mean-reverting process as well as a slowly varying process and the local volatility part is a power (the elasticity parameter) of the project value itself. The elasticity parameter controls directly the correlation between the project value and the volatility. Knowing that the project value represents the market price of a real asset in many applications and the value of the elasticity parameter depends on the asset, the elasticity parameter should be treated with caution for investment decision problems. Based on the hybrid structure of volatility, we investigate the simultaneous impact of the elasticity and the stochastic volatility on the real option value as well as the investment threshold

Nature's starships. I. Observed abundances and relative frequencies of amino acids in meteorites

International Nuclear Information System (INIS)

Cobb, Alyssa K.; Pudritz, Ralph E.

2014-01-01

The class of meteorites called carbonaceous chondrites are examples of material from the solar system which have been relatively unchanged from the time of their initial formation. These meteorites have been classified according to the temperatures and physical conditions of their parent planetesimals. We collate available data on amino acid abundance in these meteorites and plot the concentrations of different amino acids for each meteorite within various meteorite subclasses. We plot average concentrations for various amino acids across meteorites separated by subclass and petrologic type. We see a predominance in the abundance and variety of amino acids in CM2 and CR2 meteorites. The range in temperature corresponding to these subclasses indicates high degrees of aqueous alteration, suggesting aqueous synthesis of amino acids. Within the CM2 and CR2 subclasses, we identify trends in relative frequencies of amino acids to investigate how common amino acids are as a function of their chemical complexity. These two trends (total abundance and relative frequencies) can be used to constrain formation parameters of amino acids within planetesimals. Our organization of the data supports an onion shell model for the temperature structure of planetesimals. The least altered meteorites (type 3) and their amino acids originated near cooler surface regions. The most active amino acid synthesis likely took place at intermediate depths (type 2). The most altered materials (type 1) originated furthest toward parent body cores. This region is likely too hot to either favor amino acid synthesis or for amino acids to be retained after synthesis.

Autoradiographic methods for studying marked volatile substances (1961); Methode.d'etude autoradiographique de substances marquees volatiles (1961)

Energy Technology Data Exchange (ETDEWEB)

Cohen, Y; Wepierre, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1961-07-01

The autoradiographic methods for animals used up to the present do not make it possible to localise exactly the distribution of marked volatile molecules. The Ullberg method (1954) which we have modified (Cohen, Delassue, 1959) involves cold desiccant. The method due to Pellerin (1957) avoids this desiccant but the histological comparison of the autoradiography with the biological document itself is difficult, if not impossible. Nevertheless, we have adopted certain points in the two methods and propose the following technique for the autoradiographic study of marked volatile molecules: 1- The surface of the frozen sample to be studied is prepared using a freezing microtome. 2- The last section, which is 20 {mu} thick and whose histological elements are parallel to those of the block, is dried by cooling and is used as the biological reference document for the autoradiography obtained, as is indicated in 3; 3- The radiography films are applied to the frozen block at -30 deg. C. The autoradiographs correspond to the radioactivity of the volatile molecule and of its non-volatile degradation products. 4- The radiographic film is also applied to the 20 {mu} section previously dried at -20 deg. C. This autoradiography corresponds to the radioactivity of the non-volatile degradation products of the molecule. 5- We confirmed the absence of diffusion of the volatile molecule and of pseudo-radiographic effects (photochemical and others). This method, which has enabled us to study the distribution of a carbide, para-cymene (C{sup 14}) 7, macroscopically in the case of a whole mouse and microscopically on the skin of a dog, can find general applications. (authors) [French] Les methodes d'autoradiographies sur l'animal, proposees jusqu'a present, ne permettent pas de localiser de facon precise la distribution de molecules marquees volatiles. En effet, la methode de Ullberg (1954) que nous avons modifiee (Cohen, Delassue, 1959) necessite la dessiccation par le froid. La methode

The Volatility Effect: Lower Risk without Lower Return

NARCIS (Netherlands)

D.C. Blitz (David); P. van Vliet (Pim)

2007-01-01

textabstractWe present empirical evidence that stocks with low volatility earn high risk-adjusted returns. The annual alpha spread of global low versus high volatility decile portfolios amounts to 12% over the 1986-2006 period. We also observe this volatility effect within the US, European and

The Short-Time Behaviour of VIX Implied Volatilities in a Multifactor Stochastic Volatility Framework

DEFF Research Database (Denmark)

Barletta, Andrea; Nicolato, Elisa; Pagliarani, Stefano

error bounds for VIX futures, options and implied volatilities. In particular, we derive exact asymptotic results for VIX implied volatilities, and their sensitivities, in the joint limit of short time-to-maturity and small log-moneyness. The obtained expansions are explicit, based on elementary...... approximations of equity (SPX) options. However, the generalizations needed to cover the case of VIX options are by no means straightforward as the dynamics of the underlying VIX futures are not explicitly known. To illustrate the accuracy of our technique, we provide numerical implementations for a selection...... functions and they neatly uncover how the VIX skew depends on the specific choice of the volatility and the vol-of-vol processes. Our results are based on perturbation techniques applied to the infinitesimal generator of the underlying process. This methodology has been previously adopted to derive...

Release of volatile mercury from vascular plants

Science.gov (United States)

Siegel, S. M.; Puerner, N. J.; Speitel, T. W.

1974-01-01

Volatile, organic solvent soluble mercury has been found in leaves and seeds of several angiosperms. Leaves of garlic vine, avocado, and haole-koa release mercury in volatile form rapidly at room temperature. In garlic vine, the most active release is temperature dependent, but does not parallel the vapor-pressure temperature relationship for mercury. Mercury can be trapped in nitric-perchloric acid digestion fluid, or n-hexane, but is lost from the hexane unless the acid mixture is present. Seeds of haole-koa also contain extractable mercury but volatility declines in the series n-hexane (90%), methanol (50%), water (10%). This suggests that reduced volatility may accompany solvolysis in the more polar media.

Effect of the partial NaCl substitution by other chloride salts on the volatile profile during the ripening of dry-cured lacón

Energy Technology Data Exchange (ETDEWEB)

Dominguez, R.; Munekata, P.E.; Cittadini, A.; Lorenzo, J.M.

2016-07-01

The influence of three salting treatments (treatment II: 50% NaCl-50% KCl; III: 45% NaCl-25% KCl-20% CaCl2-10% MgCl2; IV: 30% NaCl-50% KCl-15% CaCl2-5% MgCl2) on the formation of volatile compounds throughout the process was studied and compared to those of a control “lacón” (treatment I: 100% NaCl). There was an intense formation of volatile compounds throughout the processing, particularly during the dry-ripening stage. The most abundant chemical family in all the formulations, in the final product was hydrocarbons followed by aldehydes. The total volatile compound release was more intense in the control “lacóns” (1164 AU×106 ·g–1dry matter) than in “lacóns” from formulations II, III and IV (817–891 AU×106 ·g−1dry matter). The “lacóns” from formulation I showed the highest amounts of aldehydes. The “lacóns” from formulations I and II presented the highest amounts of hydrocarbons. The main conclusion is that the replacement of NaCl produces changes in the volatile profile and could be affect the aroma of “lacón”. (Author)

Investigate Volatility Jumps in Chinese Stock Index Future and Spot Markets Based on Realized Volatility

Institute of Scientific and Technical Information of China (English)

Zhang qiang

2014-01-01

This paper aims to investigate Chinese stock index future and spot market's volatility jumps characteristics by using recentlydeveloped jumpstest(Barndorff-Nielsenand Shephard,2004).Thedataisoneyearhigh frequencydatafromthe period19/04/2012 to 19/04/2013. The empirical results show two important points. Firstly, the logarithm of adjusted realized volatility shows a high degree of autocorrelation and folows a normal distribution nearly perfect. These characteristics show a potential high forecast ability. Secondly,thedailyrealizedvolatilityjumpsshowalowdegreeofautocorrealtionbutwithsignificantvolatilityclusters.Ingeneral,thejumps component has a low percentage in realized volatility estimation for both future and spot market. On average, there is one significant jumpswithinevery ten continue trading days.Spotmarkets showshigherdegree of jumps,anda rapidly jumpscharacterises.It implies that jumps may transmission from spot to future market, and spot market dominate future market at some degree.

Volatility forecasting for low-volatility portfolio selection in the US and the Korean equity markets

Science.gov (United States)

Kim, Saejoon

2018-01-01

We consider the problem of low-volatility portfolio selection which has been the subject of extensive research in the field of portfolio selection. To improve the currently existing techniques that rely purely on past information to select low-volatility portfolios, this paper investigates the use of time series regression techniques that make forecasts of future volatility to select the portfolios. In particular, for the first time, the utility of support vector regression and its enhancements as portfolio selection techniques is provided. It is shown that our regression-based portfolio selection provides attractive outperformances compared to the benchmark index and the portfolio defined by a well-known strategy on the data-sets of the S&P 500 and the KOSPI 200.

Emission of volatile sulfur compounds during composting of municipal solid waste (MSW)

Energy Technology Data Exchange (ETDEWEB)

Zhang, Hongyu [Beijing Building Materials Academy of Science Research/State Key Laboratory of Solid Waste Reuse for Building Material, Beijing 100041 (China); College of Resources and Environment Sciences, China Agricultural University, Beijing 100094 (China); Schuchardt, Frank [Johann Heinrich von Thuenen-Institute, Institute of Agricultural Technology and Biosystems Engineering, Bundesallee 50, 38116 Braunschweig (Germany); Li, Guoxue, E-mail: ligx@cau.edu.cn [College of Resources and Environment Sciences, China Agricultural University, Beijing 100094 (China); Yang, Jinbing; Yang, Qingyuan [College of Resources and Environment Sciences, China Agricultural University, Beijing 100094 (China)

2013-04-15

Highlights: ► We compare the volatile sulfur compounds (VSCs) emissions during three types of municipal solid wastes (MSWs) composting. ► The VSCs released from the kitchen waste composting was significantly higher than that from 15–80 mm fraction of MSW. ► Among the five VSCs, H{sub 2}S was the most abundant compound with 39.0–43.0% of total VSCs released. ► Addition of 20% cornstalks could significantly reduce the VSCs emissions during kitchen waste composting. - Abstract: Volatile sulfur compounds (VSCs) are the main source for malodor from composting plants. In this study, the VSCs generated from composting of 15–80 mm municipal solid waste (T0), kitchen waste (T1) and kitchen waste mixed dry cornstalks (T2) were measured in 60 L reactors with forced aeration for a period of 30 days. The VSCs detected in all treatments were hydrogen sulfide (H{sub 2}S), methyl mercaptan (MM), dimethyl sulfide (DMS), carbon bisulfide (CS{sub 2}) and dimethyl disulfide (DMDS). Over 90% of the VSCs emissions occurred during the first 15 days, and reached their peak values at days 4–7. The emission profiles of five VSCs species were significantly correlated with internal materials temperature and outlet O{sub 2} concentration (p < 0.05). Total emissions of the VSCs were 216.1, 379.3 and 126.0 mg kg{sup −1} (dry matter) for T0, T1 and T2, respectively. Among the five VSCs, H{sub 2}S was the most abundant compound with 39.0–43.0% of total VSCs released. Composting of kitchen waste from separate collection posed a negative influence on the VSC and leachate production because of its high moisture content. An addition of dry cornstalks at a mixing ratio of 4:1 (wet weight) could significantly reduce the VSCs emissions and avoid leachate. Compared to pure kitchen waste, VSCs were reduced 66.8%.

Fundamental uncertainty and stock market volatility

NARCIS (Netherlands)

Arnold, I.J.M.; Vrugt, E.B.

2008-01-01

We provide empirical evidence on the link between stock market volatility and macroeconomic uncertainty. We show that US stock market volatility is significantly related to the dispersion in economic forecasts from participants in the Survey of Professional Forecasters over the period 1969 to 1996.

Estimation of Stochastic Volatility Models by Nonparametric Filtering

DEFF Research Database (Denmark)

Kanaya, Shin; Kristensen, Dennis

2016-01-01

/estimated volatility process replacing the latent process. Our estimation strategy is applicable to both parametric and nonparametric stochastic volatility models, and can handle both jumps and market microstructure noise. The resulting estimators of the stochastic volatility model will carry additional biases...... and variances due to the first-step estimation, but under regularity conditions we show that these vanish asymptotically and our estimators inherit the asymptotic properties of the infeasible estimators based on observations of the volatility process. A simulation study examines the finite-sample properties...

Volatile flavor compounds in yogurt: a review.

Science.gov (United States)

Cheng, Hefa

2010-11-01

Considerable knowledge has been accumulated on the volatile compounds contributing to the aroma and flavor of yogurt. This review outlines the production of the major flavor compounds in yogurt fermentation and the analysis techniques, both instrumental and sensory, for quantifying the volatile compounds in yogurt. The volatile compounds that have been identified in plain yogurt are summarized, with the few key aroma compounds described in detail. Most flavor compounds in yogurt are produced from lipolysis of milkfat and microbiological transformations of lactose and citrate. More than 100 volatiles, including carbonyl compounds, alcohols, acids, esters, hydrocarbons, aromatic compounds, sulfur-containing compounds, and heterocyclic compounds, are found in yogurt at low to trace concentrations. Besides lactic acid, acetaldehyde, diacetyl, acetoin, acetone, and 2-butanone contribute most to the typical aroma and flavor of yogurt. Extended storage of yogurt causes off-flavor development, which is mainly attributed to the production of undesired aldehydes and fatty acids during lipid oxidation. Further work on studying the volatile flavor compounds-matrix interactions, flavor release mechanisms, and the synergistic effect of flavor compounds, and on correlating the sensory properties of yogurt with the compositions of volatile flavor compounds are needed to fully elucidate yogurt aroma and flavor.

Long- and Short-Term Cryptocurrency Volatility Components: A GARCH-MIDAS Analysis

Directory of Open Access Journals (Sweden)

Christian Conrad

2018-05-01

Full Text Available We use the GARCH-MIDAS model to extract the long- and short-term volatility components of cryptocurrencies. As potential drivers of Bitcoin volatility, we consider measures of volatility and risk in the US stock market as well as a measure of global economic activity. We find that S&P 500 realized volatility has a negative and highly significant effect on long-term Bitcoin volatility. The finding is atypical for volatility co-movements across financial markets. Moreover, we find that the S&P 500 volatility risk premium has a significantly positive effect on long-term Bitcoin volatility. Finally, we find a strong positive association between the Baltic dry index and long-term Bitcoin volatility. This result shows that Bitcoin volatility is closely linked to global economic activity. Overall, our findings can be used to construct improved forecasts of long-term Bitcoin volatility.

A Jump Diffusion Model for Volatility and Duration

DEFF Research Database (Denmark)

Wei, Wei; Pelletier, Denis

by the market microstructure theory. Traditional measures of volatility do not utilize durations. I adopt a jump diffusion process to model the persistence of intraday volatility and conditional duration, and their interdependence. The jump component is disentangled from the continuous part of the price......, volatility and conditional duration process. I develop a MCMC algorithm for the inference of irregularly spaced multivariate process with jumps. The algorithm provides smoothed estimates of the latent variables such as spot volatility, jump times and jump sizes. I apply this model to IBM data and I find...... meaningful relationship between volatility and conditional duration. Also, jumps play an important role in the total variation, but the jump variation is smaller than traditional measures that use returns sampled at lower frequency....

[Study on absorbing volatile oil with mesoporous carbon].

Science.gov (United States)

Yan, Hong-mei; Jia, Xiao-bin; Zhang, Zhen-hai; Sun, E; Yang Nan

2014-11-01

Clove oil and turmeric oil were absorbed by mesoporous carbon. The absorption ratio of mesoporous carbon to volatile oil was optimized with the eugenol yield and curcumol yield as criteria Curing powder was characterized by scanning electron microscopy (SEM) and differential scanning calorietry (DSC). The effects of mesoporous carbon on dissolution in vitro and thermal stability of active components were studied. They reached high adsorption rate when the absorption ratio of mesoporous carbon to volatile oil was 1:1. When volatile oil was absorbed, dissolution rate of active components had a little improvement and their thermal stability improved after volatile oil was absorbed by the loss rate decreasing more than 50%. Absorbing herbal volatile oil with mesoporous carbon deserves further studying.

Gasoline taxes and revenue volatility: An application to California

International Nuclear Information System (INIS)

Madowitz, M.; Novan, K.

2013-01-01

This paper examines how applying different combinations of excise and sales taxes on motor fuels impact the volatility of retail fuel prices and tax revenues. Two features of gasoline and diesel markets make the choice of tax mechanism a unique problem. First, prices are very volatile. Second, demand for motor fuels is extremely inelastic. As a result, fuel expenditures vary substantially over time. Tying state revenues to these expenditures, as is the case with a sales tax, results in a volatile stream of revenue which imposes real costs on agents in an economy. On July 1, 2010, California enacted Assembly Bill x8-6, the “Gas Tax Swap”, increasing the excise tax and decreasing the sales tax on gasoline purchases. While the initial motivation behind the revenue neutral swap was to provide the state with greater flexibility within its budget, we highlight that this change has two potentially overlooked benefits; it reduces retail fuel price volatility and tax revenue volatility. Simulating the monthly fuel prices and tax revenues under alternative tax policies, we quantify the potential reductions in revenue volatility. The results reveal that greater benefits can be achieved by going beyond the tax swap and eliminating the gasoline sales tax entirely. - Highlights: • We examine how gasoline taxes affect government revenue volatility. • We simulate the impact of California's Gasoline Tax Swap policy. • Sales taxes are shown to magnify price volatility and government revenue volatility. • A pure excise tax policy results in less volatile fuel prices and state revenues. • We argue that reductions in both forms of volatility are welfare enhancing

Biogenic volatile emissions from the soil.

Science.gov (United States)

Peñuelas, J; Asensio, D; Tholl, D; Wenke, K; Rosenkranz, M; Piechulla, B; Schnitzler, J P

2014-08-01

Volatile compounds are usually associated with an appearance/presence in the atmosphere. Recent advances, however, indicated that the soil is a huge reservoir and source of biogenic volatile organic compounds (bVOCs), which are formed from decomposing litter and dead organic material or are synthesized by underground living organism or organs and tissues of plants. This review summarizes the scarce available data on the exchange of VOCs between soil and atmosphere and the features of the soil and particle structure allowing diffusion of volatiles in the soil, which is the prerequisite for biological VOC-based interactions. In fact, soil may function either as a sink or as a source of bVOCs. Soil VOC emissions to the atmosphere are often 1-2 (0-3) orders of magnitude lower than those from aboveground vegetation. Microorganisms and the plant root system are the major sources for bVOCs. The current methodology to detect belowground volatiles is described as well as the metabolic capabilities resulting in the wealth of microbial and root VOC emissions. Furthermore, VOC profiles are discussed as non-destructive fingerprints for the detection of organisms. In the last chapter, belowground volatile-based bi- and multi-trophic interactions between microorganisms, plants and invertebrates in the soil are discussed. © 2014 John Wiley & Sons Ltd.

The Fe/Mn constraint on precursors of basaltic achondrites

Science.gov (United States)

Delaney, Jeremy S.; Boesenberg, Joseph S.

1993-01-01

Most achondritic meteorites have Fe/Mn ratios that are lower than those of carbonaceous chondrites and of course are lower than the solar system abundance ratio of these elements. Models of the origin of achondritic assemblages must, therefore, account for these ratios. Fe/Mn ratios are suggested to be distinctive for samples from each achondrite parent body and for the Earth and Moon, but the correspondence between the Fe/Mn systematics of achondrites and chondritic precursors is unclear. Most models of achondrite genesis involve magmatic differentiation of chondritic precursors. The Fe/Mn difference between achondrites and chondrites is particularly significant since Fe and Mn are geochemically similar elements with similar partitioning behavior in familiar magmatic systems and are generally coupled during crystal-liquid fractionation. In contrast, however, Mn is more volatile than Fe in a nebular setting. Variation of Fe/Mn ratios based on the relative volatility of these elements in the early nebula provides a constraint for models by which the basaltic achondrites (with Fe/Mn ratios approximately = 25-50) are derived from mixtures of nebular components that were enriched in volatile components such as Mn. However, such volatile enriched components have not been identified in chondrites. When the abundance in achondrites of elements of similar volatility is examined, anomalies appear. For example, Na is massively depleted in basaltic achondrites when compared to Mn. These anomalies might be explained using current models but the alternative hypothesis, that Fe/Mn ratio is controlled not by nebular volatility constraints, but by planetary differentiation should be explored.

The Forecast Performance of Competing Implied Volatility Measures

DEFF Research Database (Denmark)

Tsiaras, Leonidas

This study examines the information content of alternative implied volatility measures for the 30 components of the Dow Jones Industrial Average Index from 1996 until 2007. Along with the popular Black-Scholes and "model-free" implied volatility expectations, the recently proposed corridor implie......, volatility definitions, loss functions and forecast evaluation settings....

Stock market volatility and macroeconomic uncertainty

NARCIS (Netherlands)

Arnold, I.J.M.; Vrugt, E.B.

2006-01-01

This paper provides empirical evidence on the link between stock market volatility and macroeconomic uncertainty. We show that US stock market volatility is significantly related to the dispersion in economic forecasts from SPF survey participants over the period from 1969 to 1996. This link is much

CHEMICAL INVESTIGATION OF THE VOLATILE CONSTITUENTS ...

African Journals Online (AJOL)

CHEMICAL INVESTIGATION OF THE VOLATILE CONSTITUENTS OF CLEOME VISCOSA FROM NIGERIA. Gabriel Olatunji, Peter Weyerstahl, Stephen Oguntoye. Abstract. The major volatile constituents of the oils from the integral parts of Cleome viscosa L. from Nigeria have been identified by GC, GC/MS and 1H NMR.

Long Memory in STOCK Market Volatility: the International Evidence

Science.gov (United States)

Yang, Chunxia; Hu, Sen; Xia, Bingying; Wang, Rui

2012-08-01

It is still a hot topic to catch the auto-dependence behavior of volatility. Here, based on the measurement of average volatility, under different observation window size, we investigated the dependence of successive volatility of several main stock indices and their simulated GARCH(1, 1) model, there were obvious linear auto-dependence in the logarithm of volatility under a small observation window size and nonlinear auto-dependence under a big observation. After calculating the correlation and mutual information of the logarithm of volatility for Dow Jones Industrial Average during different periods, we find that some influential events can change the correlation structure and the volatilities of different periods have distinct influence on that of the remote future. Besides, GARCH model could produce similar behavior of dependence as real data and long memory property. But our analyses show that the auto-dependence of volatility in GARCH is different from that in real data, and the long memory is undervalued by GARCH.

Do energy prices stimulate food price volatility? Examining volatility transmission between US oil, ethanol and corn markets

NARCIS (Netherlands)

Gardebroek, C.; Hernandez, M.A.

2013-01-01

This paper examines volatility transmission in oil, ethanol and corn prices in the United States between 1997 and 2011. We follow a multivariate GARCH approach to evaluate the level of interdependence and the dynamics of volatility across these markets. Preliminary results indicate a higher

Do energy prices stimulate food price volatility? Examining volatility transmission between US oil, ethanol and corn markets

NARCIS (Netherlands)

Gardebroek, C.; Hernandez, M.A.

2012-01-01

This paper examines volatility transmission in oil, ethanol and corn prices in the United States between 1997 and 2011. We follow a multivariate GARCH approach to evaluate the level of interdependence and the dynamics of volatility across these markets. Preliminary results indicate a higher

Do energy prices stimulate food price volatility? Examining volatility transmission between US oil, ethanol and corn markets

NARCIS (Netherlands)

Hernandez, M.A.; Gardebroek, C.

2012-01-01

This paper examines volatility transmission in oil, ethanol and corn prices in the United States between 1997 and 2011. We follow a multivariate GARCH approach to evaluate the level of interdependence and the dynamics of volatility across these markets. The estimation results indicate a higher

Option Valuation with Observable Volatility and Jump Dynamics

DEFF Research Database (Denmark)

Christoffersen, Peter; Feunoua, Bruno; Jeon, Yoontae

Under very general conditions, the total quadratic variation of a jump-diffusion process can be decomposed into diffusive volatility and squared jump variation. We use this result to develop a new option valuation model in which the underlying asset price exhibits volatility and jump intensity...... dynamics. The volatility and jump intensity dynamics in the model are directly driven by model-free empirical measures of diffusive volatility and jump variation. Because the empirical measures are observed in discrete intervals, our option valuation model is cast in discrete time, allowing...

Option Valuation with Observable Volatility and Jump Dynamics

DEFF Research Database (Denmark)

Christoffersen, Peter; Feunoua, Bruno; Jeon, Yoontae

2015-01-01

Under very general conditions, the total quadratic variation of a jump-diffusion process can be decomposed into diffusive volatility and squared jump variation. We use this result to develop a new option valuation model in which the underlying asset price exhibits volatility and jump intensity...... dynamics. The volatility and jump intensity dynamics in the model are directly driven by model-free empirical measures of diffusive volatility and jump variation. Because the empirical measures are observed in discrete intervals, our option valuation model is cast in discrete time, allowing...

In-tube extraction for the determination of the main volatile compounds in Physalis peruviana L.

Science.gov (United States)

Kupska, Magdalena; Jeleń, Henryk H

2017-01-01

An analytical procedure based on in-tube extraction followed by gas chromatography with mass spectrometry has been developed for the analysis of 24 of the main volatile components in cape gooseberry (Physalis peruviana L.) samples. According to their chemical structure, the compounds were organized into different groups: one hydrocarbon, one aldehyde, four alcohols, four esters, and 14 monoterpenes. By single-factor experiments, incubation temperature, incubation time, extraction volume, extraction strokes, extraction speed, desorption temperature, and desorption speed were determined as 60°C, 20 min, 1000 μL, 20, 50:50 μL/s, 280°C, 100 μL/s, respectively. Quantitative analysis using authentic standards and external calibration curves was performed. The limit of detection and limit of quantification for the analytical procedure were calculated. Results shown the benzaldehyde, ethyl butanoate, 2-methyl-1-butanol, 1-hexanol, 1-butanol, α-terpineol, and terpinen-4-ol were the most abundant volatile compounds in analyzed fruits (68.6-585 μg/kg). The obtained data may contribute to qualify cape gooseberry to the group of superfruits and, therefore, increase its popularity. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Time-varying volatility in Malaysian stock exchange: An empirical study using multiple-volatility-shift fractionally integrated model

Science.gov (United States)

Cheong, Chin Wen

2008-02-01

This article investigated the influences of structural breaks on the fractionally integrated time-varying volatility model in the Malaysian stock markets which included the Kuala Lumpur composite index and four major sectoral indices. A fractionally integrated time-varying volatility model combined with sudden changes is developed to study the possibility of structural change in the empirical data sets. Our empirical results showed substantial reduction in fractional differencing parameters after the inclusion of structural change during the Asian financial and currency crises. Moreover, the fractionally integrated model with sudden change in volatility performed better in the estimation and specification evaluations.

Volatility estimation using a rational GARCH model

Directory of Open Access Journals (Sweden)

Tetsuya Takaishi

2018-03-01

Full Text Available The rational GARCH (RGARCH model has been proposed as an alternative GARCHmodel that captures the asymmetric property of volatility. In addition to the previously proposedRGARCH model, we propose an alternative RGARCH model called the RGARCH-Exp model thatis more stable when dealing with outliers. We measure the performance of the volatility estimationby a loss function calculated using realized volatility as a proxy for true volatility and compare theRGARCH-type models with other asymmetric type models such as the EGARCH and GJR models.We conduct empirical studies of six stocks on the Tokyo Stock Exchange and find that a volatilityestimation using the RGARCH-type models outperforms the GARCH model and is comparable toother asymmetric GARCH models.

MACROECONOMIC VARIABLES AND STOCK PRICE VOLATILITY IN NIGERIA

Directory of Open Access Journals (Sweden)

OSAZEE GODWIN OMOROKUNWA

2014-10-01

Full Text Available The purpose of this paper is to examine the relationship between stock price volatility and few macroeconomic variables such as inflation, exchange rate, GDP and interest rate. Annual time series data ranging from 1980 to 2011 was used for this study. The generalized autoregressive conditional heteroskedasticity (GARCH model was used in the empirical analysis. The findings of the study showed that stock prices in Nigeria are volatile. And that past information in the market have effect on stock price volatility in Nigeria. In addition, the study showed that interest rate and exchange have a weak effect on stock price volatility while inflation is the main determinant of stock price volatility in Nigeria. The authors recommend that inflation should be targeted as the main monetary policy aimed at directing the stock market.

Identify and Manage the Software Requirements Volatility

OpenAIRE

Khloud Abd Elwahab; Mahmoud Abd EL Latif; Sherif Kholeif

2016-01-01

Management of software requirements volatility through development of life cycle is a very important stage. It helps the team to control significant impact all over the project (cost, time and effort), and also it keeps the project on track, to finally satisfy the user which is the main success criteria for the software project. In this research paper, we have analysed the root causes of requirements volatility through a proposed framework presenting the requirements volatility causes and how...

Volatility in GARCH Models of Business Tendency Index

Science.gov (United States)

Wahyuni, Dwi A. S.; Wage, Sutarman; Hartono, Ateng

2018-01-01

This paper aims to obtain a model of business tendency index by considering volatility factor. Volatility factor detected by ARCH (Autoregressive Conditional Heteroscedasticity). The ARCH checking was performed using the Lagrange multiplier test. The modeling is Generalized Autoregressive Conditional Heteroscedasticity (GARCH) are able to overcome volatility problems by incorporating past residual elements and residual variants.

40 CFR 53.66 - Test procedure: Volatility test.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 5 2010-07-01 2010-07-01 false Test procedure: Volatility test. 53.66... Characteristics of Class II Equivalent Methods for PM2.5 § 53.66 Test procedure: Volatility test. (a) Overview. This test is designed to ensure that the candidate method's losses due to volatility when sampling semi...

Does NVIX matter for market volatility? Evidence from Asia-Pacific markets

Science.gov (United States)

Su, Zhi; Fang, Tong; Yin, Libo

2018-02-01

Forecasting financial market volatility is an important issue in the area of econophysics, and revealing the determinants of the market volatility has drawn much attentions of the academics. In order to better predict market volatilities, we use news-based implied volatility (NVIX) to measure uncertainty, and examine the predictive power of NVIX on the stock market volatility in both long and short-term among Asia-Pacific markets via GARCH-MIDAS model. We find that NVIX does not well explain long-term volatility variants in the full sample period, and it is positively associated with market volatility through a subsample analysis starting from the Financial Crisis. We also find that NVIX is more efficient in determining short-term volatility than the long-term volatility, indicating that the impact of NVIX is short-lived and information that investors concern could be quickly reflected in the stock market volatilities.

Long memory and tail dependence in trading volume and volatility

DEFF Research Database (Denmark)

Rossi, Eduardo; Santucci de Magistris, Paolo

2013-01-01

We investigate the relationship between volatility, measured by realized volatility, and trading volume for 25 NYSE stocks. We show that volume and volatility are long memory but not fractionally cointegrated in most cases. We also find right tail dependence in the volatility and volume innovations...

Pyrolysis and volatilization of cocaine

International Nuclear Information System (INIS)

Martin, B.R.; Lue, L.P.; Boni, J.P.

1989-01-01

The increasing popularity of inhaling cocaine vapor prompted the present study, to determine cocaine's fate during this process. The free base of [3H]cocaine (1 microCi/50 mg) was added to a glass pipe, which was then heated in a furnace to simulate freebasing. Negative pressure was used to draw the vapor through a series of glass wool, ethanol, acidic, and basic traps. Air flow rate and temperature were found to have profound effects on the volatilization and pyrolysis of cocaine. At a temperature of 260 degrees C and a flow rate of 400 mL/min, 37% of the radioactivity remained in the pipe, 39% was found in the glass wool trap, and less than 1% in the remainder of the volatilization apparatus after a 10-min volatilization. Reducing the air flow rate to 100 mL/min reduced the amount of radioactivity collected in the glass wool trap to less than 10% of the starting material and increased the amount that remained in the pipe to 58%. GC/MS analysis of the contents of the glass wool trap after volatilization at 260 degrees C and a flow rate of 400 mL/min revealed that 60% of the cocaine remained intact, while approximately 6 and 2% of the starting material was recovered as benzoic acid and methylecgonidine, respectively. As the temperature was increased to 650 degrees C, benzoic acid and methylecgonidine accounted for 83 and 89% of the starting material, respectively, whereas only 2% of the cocaine remained intact. Quantitation of cocaine in the vapor during the course of volatilization revealed high concentrations during the first two min and low concentrations for the remaining time

Study on off-odor volatiles of irradiated packaged raw pork

International Nuclear Information System (INIS)

Lin Ruotai; Geng Shengrong; Liu Yangmin

2008-01-01

Analysing the compositions of off-odor volatiles in irradiated refrigerated vacuum-packaged pork and research on its origin. First, the off-odor volatiles were collected by a cooled via in liquid nitrogen, then the main composition of off-odor volatiles were analyzed by gas chromatograph mass spectrometry (GC-MS). The main composition of off-odor volatiles are dimethyl disulfide, dimethyl sulfide, dimethyl trisulfide, methanethiol and S-methyl thioacetate. The off-odor volatiles come from irradiated cystine, methionine and VB1. The main composition of off-odor volatiles are S-containing compounds from irradiated S-containing amino acid and VB1

Sodium channels as targets for volatile anesthetics

Directory of Open Access Journals (Sweden)

Karl F. Herold

2012-03-01

Full Text Available The molecular mechanisms of modern inhaled anesthetics although widely used in clinical settings are still poorly understood. Considerable evidence supports effects on membrane proteins such as ligand- and voltage-gated ion channels of excitable cells. Na+ channels are crucial to action potential initiation and propagation, and represent potential targets for volatile anesthetics. Inhibition of presynaptic Na+ channels leads to reduced neurotransmitter release at the synapse and could therefore contribute to the mechanisms by which volatile anesthetics produce their characteristic effects: amnesia, unconsciousness, and immobility. Early studies on crayfish and squid giant axon showed inhibition of Na+ currents by volatile anesthetics. Subsequent studies using native neuronal preparations and heterologous expression systems with various mammalian Na+ channel isoforms implicated inhibition of presynaptic Na+ channels in anesthetic actions. Volatile anesthetics reduce peak Na+ current and shift the voltage of half-maximal steady-state inactivation towards more negative potentials, thus stabilizing the fast-inactivated state. Furthermore recovery from fast-inactivation is slowed together with an enhanced use-dependent block during pulse train protocols. These effects can reduce neurotransmitter release by depressing presynaptic excitability, depolarization and Ca entry, and ultimately transmitter release. This reduction in transmitter release is more portent for glutamatergic vs. GABAergic terminals. Involvement of Na+ channel inhibition in mediating the immobility caused by volatile anesthetics has been demonstrated in animal studies, in which intrathecal infusion of the Na+ channel blocker tetrodotoxin increases volatile anesthetic potency, whereas infusion of the Na+ channels agonist veratridine reduces anesthetic potency. These studies indicate that inhibition of presynaptic Na+ channels by volatile anesthetics is involved in mediating some of

Volatile Metabolomic Composition of Vitex Species: Chemodiversity Insights and Acaricidal Activity

Directory of Open Access Journals (Sweden)

José G. de Sena Filho

2017-11-01

Full Text Available The Vitex genus (Lamiaceae produces a plethora of metabolites that include ecdysteroids and terpenoids, some of which have demonstrated insect repellent properties. The volatile composition of several members of this genus has not been chemically defined, as many taxa are endemic to remote ecosystems. In this study, leaves were collected from the northeast of Brazil from Vitex capitata, V. megapotamica, V. gardneriana, and V. rufescens plants and examined for their chemical profile via GC-MS/FID of essential oil extracts. The analyses showed a diversity of terpenoids. Of particular note were seven-member ring sesquiterpenes which were present in great abundance; a dendrogram showed clades separating by the production of bicyclogermacrene, aromadendrane and 5,10-cycloaromadendrane sesquiterpenoids for the four species. Comparison of volatile metabolite profiles to 13 other Vitex species showed strong similarities in the production of some monoterpenes, but varied by their production of larger terpenes, especially those with gem-dimethylcyclopropyl subunits on seven-member ring compounds. From this work, we suggest that the sesquiterpene skeleton with seven member rings is a good chemosystematic biomarker candidate for the Vitex genus. Separation using this biomarker was then validated using Inter-Simple Sequence Repeat profiling. Lastly, experiments examining the toxicity of these four oils against the coconut mite Aceria guerreronis showed that only the oil of V. gardneriana had strong acaricidal activity, with an LC50 of 0.85 mg/mL, thus demonstrating its potential for use as a natural pesticide.

Can Internet search queries help to predict stock market volatility?

OpenAIRE

Dimpfl, Thomas; Jank, Stephan

2011-01-01

This paper studies the dynamics of stock market volatility and retail investor attention measured by internet search queries. We find a strong co-movement of stock market indices’ realized volatility and the search queries for their names. Furthermore, Granger causality is bi-directional: high searches follow high volatility, and high volatility follows high searches. Using the latter feedback effect to predict volatility we find that search queries contain additional information about market...

Modelling of volatility in monetary transmission mechanism

Energy Technology Data Exchange (ETDEWEB)

Dobešová, Anna; Klepáč, Václav; Kolman, Pavel [Department of Statistics and Operation Analysis, Faculty of Business and Economics, Mendel University in Brno, Zemědělská 1, 61300, Brno (Czech Republic); Bednářová, Petra [Institute of Technology and Business, Okružní 517/10, 370 01, České Budějovice (Czech Republic)

2015-03-10

The aim of this paper is to compare different approaches to modeling of volatility in monetary transmission mechanism. For this purpose we built time-varying parameter VAR (TVP-VAR) model with stochastic volatility and VAR-DCC-GARCH model with conditional variance. The data from three European countries are included in the analysis: the Czech Republic, Germany and Slovakia. Results show that VAR-DCC-GARCH system captures higher volatility of observed variables but main trends and detected breaks are generally identical in both approaches.

Modelling of volatility in monetary transmission mechanism

International Nuclear Information System (INIS)

Dobešová, Anna; Klepáč, Václav; Kolman, Pavel; Bednářová, Petra

2015-01-01

The aim of this paper is to compare different approaches to modeling of volatility in monetary transmission mechanism. For this purpose we built time-varying parameter VAR (TVP-VAR) model with stochastic volatility and VAR-DCC-GARCH model with conditional variance. The data from three European countries are included in the analysis: the Czech Republic, Germany and Slovakia. Results show that VAR-DCC-GARCH system captures higher volatility of observed variables but main trends and detected breaks are generally identical in both approaches

Factor Structure in Commodity Futures Return and Volatility

DEFF Research Database (Denmark)

Christoffersen, Peter; Lunde, Asger; Olesen, Kasper Vinther

Using data on more than 750 million futures trades during 2004-2013, we analyze eight stylized facts of commodity price and volatility dynamics in the post financialization period. We pay particular attention to the factor structure in returns and volatility and to commodity market integration...... with the equity market. We find evidence of a factor structure in daily commodity futures returns. However, the factor structure in daily commodity futures volatility is even stronger than in returns. When computing model-free realized commodity betas with the stock market we find that they were high during 2008......-2010 but have since returned to the pre-crisis level close to zero. The common factor in commodity volatility is nevertheless clearly related to stock market volatility. We conclude that, while commodity markets appear to again be segmented from the equity market when only returns are considered, commodity...

Hammerstein system represention of financial volatility processes

Science.gov (United States)

Capobianco, E.

2002-05-01

We show new modeling aspects of stock return volatility processes, by first representing them through Hammerstein Systems, and by then approximating the observed and transformed dynamics with wavelet-based atomic dictionaries. We thus propose an hybrid statistical methodology for volatility approximation and non-parametric estimation, and aim to use the information embedded in a bank of volatility sources obtained by decomposing the observed signal with multiresolution techniques. Scale dependent information refers both to market activity inherent to different temporally aggregated trading horizons, and to a variable degree of sparsity in representing the signal. A decomposition of the expansion coefficients in least dependent coordinates is then implemented through Independent Component Analysis. Based on the described steps, the features of volatility can be more effectively detected through global and greedy algorithms.

Female offspring desertion and male-only care increase with natural and experimental increase in food abundance.

Science.gov (United States)

Eldegard, Katrine; Sonerud, Geir A

2009-05-07

In species with biparental care, one parent may escape the costs of parental care by deserting and leaving the partner to care for the offspring alone. A number of theoretical papers have suggested a link between uniparental offspring desertion and ecological factors, but empirical evidence is scarce. We investigated the relationship between uniparental desertion and food abundance in a natural population of Tengmalm's owl Aegolius funereus, both by means of a 5-year observational study and a 1-year experimental study. Parents and offspring were fitted with radio-transmitters in order to reveal the parental care strategy (i.e. care or desert) of individual parents, and to keep track of the broods post-fledging. We found that 70 per cent of the females from non-experimental nests deserted, while their partner continued to care for their joint offspring alone. Desertion rate was positively related to natural prey population densities and body reserves of the male partner. In response to food supplementation, a larger proportion of the females deserted, and females deserted the offspring at an earlier age. Offspring survival during the post-fledging period tended to be lower in deserted than in non-deserted broods. We argue that the most important benefit of deserting may be remating (sequential polyandry).

Volatile composition and sensory profile of Cantharellus cibarius Fr. as affected by drying method.

Science.gov (United States)

Politowicz, Joanna; Lech, Krzysztof; Sánchez-Rodríguez, Lucía; Szumny, Antoni; Carbonell-Barrachina, Ángel A

2017-12-01

In this work, the influence of different drying methods on the aroma composition and sensory quality of chanterelle mushrooms (Cantharellus cibarius Fr.) was evaluated. The drying methods tested were convective drying (CD), freeze drying (FD), vacuum microwave drying (VMD) and a combination of convective pre-drying and vacuum microwave finish drying (CPD-VMFD). Analyses of fresh and dried chanterelle samples by HS-SPME and GC/MS and GC-FID showed the presence of 39 volatile compounds at different concentrations. The most abundant compounds in fresh chanterelle were 1-hexanol (33.4 μg per 100 g dry basis (db)), 1-octen-3-ol (80.2 μg per 100 g db) and 2-octen-1-ol (19.3 μg per 100 g db). The results showed that fresh and dried chanterelle contained very low levels of aroma compounds; however, the highest contents of volatile compounds were found in samples after (i) CD at 80 °C (129 μg per 100 g db), (ii) CPD-VMFD at 70 °C-480/240 W (136 μg per 100 g db) and (iii) CPD-VMFD at 80 °C-480/240 W (136 μg per 100 g db). The best dehydration methods, which resulted in high contents of volatile compounds and appropriate sensory quality, according to descriptive sensory analysis and PCA tools, were CD at 70 and 80 °C. Besides, these methods led to spongy dried mushrooms with high intensities of fresh, mushroom ID, with proper color and without intense shrinkage. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Large deviations and stochastic volatility with jumps: asymptotic implied volatility for affine models

OpenAIRE

Antoine Jacquier; Martin Keller-Ressel; Aleksandar Mijatovic

2011-01-01

Let $\\sigma_t(x)$ denote the implied volatility at maturity $t$ for a strike $K=S_0 e^{xt}$, where $x\\in\\bbR$ and $S_0$ is the current value of the underlying. We show that $\\sigma_t(x)$ has a uniform (in $x$) limit as maturity $t$ tends to infinity, given by the formula $\\sigma_\\infty(x)=\\sqrt{2}(h^*(x)^{1/2}+(h^*(x)-x)^{1/2})$, for $x$ in some compact neighbourhood of zero in the class of affine stochastic volatility models. The function $h^*$ is the convex dual of the limiting cumulant gen...

A Fractionally Integrated Wishart Stochastic Volatility Model

NARCIS (Netherlands)

M. Asai (Manabu); M.J. McAleer (Michael)

2013-01-01

textabstractThere has recently been growing interest in modeling and estimating alternative continuous time multivariate stochastic volatility models. We propose a continuous time fractionally integrated Wishart stochastic volatility (FIWSV) process. We derive the conditional Laplace transform of

High-precision abundances of elements in Kepler LEGACY stars. Verification of trends with stellar age

Science.gov (United States)

Nissen, P. E.; Silva Aguirre, V.; Christensen-Dalsgaard, J.; Collet, R.; Grundahl, F.; Slumstrup, D.

2017-12-01

Context. A previous study of solar twin stars has revealed the existence of correlations between some abundance ratios and stellar age providing new knowledge about nucleosynthesis and Galactic chemical evolution. Aims: High-precision abundances of elements are determined for stars with asteroseismic ages in order to test the solar twin relations. Methods: HARPS-N spectra with signal-to-noise ratios S/N ≳ 250 and MARCS model atmospheres were used to derive abundances of C, O, Na, Mg, Al, Si, Ca, Ti, Cr, Fe, Ni, Zn, and Y in ten stars from the Kepler LEGACY sample (including the binary pair 16 Cyg A and B) selected to have metallicities in the range - 0.15 LTE iron abundances derived from Fe I and Fe II lines. Available non-LTE corrections were also applied when deriving abundances of the other elements. Results: The abundances of the Kepler stars support the [X/Fe]-age relations previously found for solar twins. [Mg/Fe], [Al/Fe], and [Zn/Fe] decrease by 0.1 dex over the lifetime of the Galactic thin disk due to delayed contribution of iron from Type Ia supernovae relative to prompt production of Mg, Al, and Zn in Type II supernovae. [Y/Mg] and [Y/Al], on the other hand, increase by 0.3 dex, which can be explained by an increasing contribution of s-process elements from low-mass AGB stars as time goes on. The trends of [C/Fe] and [O/Fe] are more complicated due to variations of the ratio between refractory and volatile elements among stars of similar age. Two stars with about the same age as the Sun show very different trends of [X/H] as a function of elemental condensation temperature Tc and for 16 Cyg, the two components have an abundance difference, which increases with Tc. These anomalies may be connected to planet-star interactions. Based on spectra obtained with HARPS-N@TNG under programme A33TAC_1.Tables 1 and 2 are also available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http

The volatility of stock market prices.

Science.gov (United States)

Shiller, R J

1987-01-02

If the volatility of stock market prices is to be understood in terms of the efficient markets hypothesis, then there should be evidence that true investment value changes through time sufficiently to justify the price changes. Three indicators of change in true investment value of the aggregate stock market in the United States from 1871 to 1986 are considered: changes in dividends, in real interest rates, and in a direct measure of intertemporal marginal rates of substitution. Although there are some ambiguities in interpreting the evidence, dividend changes appear to contribute very little toward justifying the observed historical volatility of stock prices. The other indicators contribute some, but still most of the volatility of stock market prices appears unexplained.

Can Equity Volatility Explain the Global Loan Pricing Puzzle?

OpenAIRE

Lewis Gaul; Pinar Uysal

2013-01-01

This paper examines whether unobservable differences in firm volatility are responsible for the global loan pricing puzzle, which is the observation that corporate loan interest rates appear to be lower in Europe than in the United States. We analyze whether equity volatility, an error prone measure of firm volatility, can explain this difference in loan spreads. We show that using equity volatility in OLS regressions will result in biased and inconsistent estimates of the difference in U.S. ...

Stock Market Volatility: Examining North America, Europe and Asia

OpenAIRE

Gamini Premaratne; Lakshmi Bala

2004-01-01

An understanding of volatility in stock markets is important for determining the cost of capital and for assessing investment and leverage decisions as volatility is synonymous with risk. Substantial changes in volatility of financial markets are capable of having significant negative effects on risk averse investors. Using daily returns from 1992 to 2002, we investigate volatility co-movement between the Singapore stock market and the markets of US, UK, Hong Kong and Japan. In order to gauge...

Multiscaling and clustering of volatility

Science.gov (United States)

Pasquini, Michele; Serva, Maurizio

1999-07-01

The dynamics of prices in stock markets has been studied intensively both experimentally (data analysis) and theoretically (models). Nevertheless, while the distribution of returns of the most important indices is known to be a truncated Lévy, the behaviour of volatility correlations is still poorly understood. What is well known is that absolute returns have memory on a long time range, this phenomenon is known in financial literature as clustering of volatility. In this paper we show that volatility correlations are power laws with a non-unique scaling exponent. This kind of multiscale phenomenology is known to be relevant in fully developed turbulence and in disordered systems and it is pointed out here for the first time for a financial series. In our study we consider the New York Stock Exchange (NYSE) daily index, from January 1966 to June 1998, for a total of 8180 working days.

Exposição ocupacional a compostos orgânicos voláteis na indústria naval Occupational exposure to volatile organic compounds in the naval industry

Directory of Open Access Journals (Sweden)

Maria de Fátima Barrozo da Costa

2002-05-01

Full Text Available The scope of this study involved the evaluation of the concentration of some volatile organic compounds in the internal environmental air of a naval shipyard in the State of Rio de Janeiro, during painting activities in enclosed, semi-enclosed and open areas. Xylene was the volatile compound found in greatest abundance (25.20 to 191.66 ppm in the locations researched. Benzene in the air, which is a carcinogenic substance, attained levels of 3.34 ppm in semi-enclosed environments and the highest levels of toluene, xylene and n-butanol were found in the enclosed space of the ship. Results obtained highlight the need to establish air quality control programs in these internal areas, in order to safeguard the health of the workers.

Evolving coma abundances and detection of hypervolatiles in Jupiter-family comet 45P/Honda-Mrkos-Pajdusakova

Science.gov (United States)

Dello Russo, Neil; DiSanti, Michael A.; Kawakita, Hideyo; Shinnaka, Yoshiharu; Vervack, Ronald J.; Bonev, Boncho P.; Gibb, Erika L.; Roth, Nathan; McKay, Adam J.; Weaver, Harold A.; Cochran, Anita L.

2017-10-01

Two major shortcomings in chemically classifying comets at infrared wavelengths are a lack of hypervolatile (CO and CH4) detections in Jupiter-family comets and incomplete temporal coverage of comet chemistry, particularly at small heliocentric distances (Rh). We report post-perihelion volatile abundances in comet 45P/Honda-Mrkos-Pajdusakova with the high-resolution infrared spectrometer iSHELL at the NASA/IRTF on UT 6 - 8 January when Rh = 0.55 AU (DiSanti et al. 2017, Astron. J., in press), and with NIRSPEC at the Keck Observatory on UT 13 and 19 February when Rh = 1.0 and 1.1 AU, respectively. Favorable comet geocentric velocities enabled the detection of CO and CH4 in early January and 19 February. The relative abundance of CO is severely depleted whereas CH4 is typical to enriched in 45P when compared to comets from the Oort cloud. Significant differences are seen in relative abundances of species between January and February, notably in the ratio of C2H2/HCN. We explore whether the heliocentric distances of the measurements or seasonal changes primarily cause these differences by comparing to observations of C/2012 S1 ISON obtained over a similar range of heliocentric distances. NASA and NSF research grants support this work. We also acknowledge the expert support of the IRTF and Keck support staffs during these observations.

Volatile compounds in meat and meat products

Directory of Open Access Journals (Sweden)

Monika KOSOWSKA

Full Text Available Abstract Meaty flavor is composed of a few hundreds of volatile compounds, only minor part of which are responsible for the characteristic odor. It is developed as a result of multi-directional reactions proceeding between non-volatile precursors contained in raw meat under the influence of temperature. The volatile compounds are generated upon: Maillard reactions, lipid oxidation, interactions between Maillard reaction products and lipid oxidation products as well as upon thiamine degradation. The developed flavor is determined by many factors associated with: raw material (breed, sex, diet and age of animal, conditions and process of slaughter, duration and conditions of meat storage, type of muscle, additives applied and the course of the technological process. The objective of this review article is to draw attention to the issue of volatile compounds characteristic for meat products and factors that affect their synthesis.

Effect of extraction time on antioxidants and bioactive volatile components of green tea (Camellia sinensis, using GC/MS

Directory of Open Access Journals (Sweden)

Mudasir Ahmad

2015-12-01

Full Text Available Two green tea types, leaf grade and sanding, were extracted at different time intervals: 20, 40, and 120 min at a constant temperature of 50°C. The extracts were analyzed by GC/MS technique. The major compounds identified were myristic acid, palmitic acid, stearic acid, oleic acid, 1H-purine-2,6-dione, caffeine, linoleic acid, diethyl ester, and 1H-purine-6-amine. Stearic acid, palmitic acid, linoleic acid, and myristic acid were more abundantly present in the leaf-grade variety than sanding. However, some levels of acetic acid, cyclobutanol, hexadecanoic acid, octadecanoic acid, 9-octadecenoic acid, and caffeine were also found in both the tea types. Most of the volatile compounds were detected between 20–40-min time of extraction. The 40-min time of extraction also showed the maximum content of polyphenols and antioxidants in both the tea types. Thus, 40 min was suggested as the most suitable time for maximum extraction of bioactive volatiles, antioxidants, and polyphenols from green tea.

Does Interest rate Exposure explain the Low-Volatility Anomaly?

NARCIS (Netherlands)

Driessen, Joost; Kuiper, Ivo; Beilo, R.

We show that part of the outperformance of low-volatility stocks can be explained by a premium for interest rate exposure. Low-volatility stock portfolios have negative exposure to interest rates, whereas the more volatile stocks have positive exposure. Incorporating an interest rate premium

Oil prices and financial stress: A volatility spillover analysis

International Nuclear Information System (INIS)

Nazlioglu, Saban; Soytas, Ugur; Gupta, Rangan

2015-01-01

This paper examines whether there is a volatility transmission between oil prices and financial stress by means of the volatility spillover test. We employ WTI crude oil prices and Cleveland financial stress index for the period 1991–2014 and divide the sample into pre-crisis, in-crisis, and post-crisis periods due to the downward trend in oil price in 2008. The volatility model estimations indicate that oil prices and financial stress index are dominated by long-run volatility. The volatility spillover causality test supports evidence on risk transfer from oil prices to financial stress before the crisis and from financial stress to oil prices after the crisis. The impulse response analysis shows that the volatility transmission pattern has similar dynamics before and after the crisis and is characterized by higher and long-lived effects during the crisis. Our results have implications for both policy makers and investors, and for future work. -- Highlights: •Volatility spillover between oil prices and financial stress index is examined. •Analysis is conducted for sub-periods: pre-crisis, in-crisis, and post-crisis •Oil prices spill on financial stress before the crisis, but spillover reversed after the crisis. •Volatility transmission pattern has similar dynamics before and after the crisis. •Implications for investors and policy makers are discussed

Silicon isotopes in angrites and volatile loss in planetesimals

Science.gov (United States)

Moynier, Frédéric; Savage, Paul S.; Badro, James; Barrat, Jean-Alix

2014-01-01

Inner solar system bodies, including the Earth, Moon, and asteroids, are depleted in volatile elements relative to chondrites. Hypotheses for this volatile element depletion include incomplete condensation from the solar nebula and volatile loss during energetic impacts. These processes are expected to each produce characteristic stable isotope signatures. However, processes of planetary differentiation may also modify the isotopic composition of geochemical reservoirs. Angrites are rare meteorites that crystallized only a few million years after calcium–aluminum-rich inclusions and exhibit extreme depletions in volatile elements relative to chondrites, making them ideal samples with which to study volatile element depletion in the early solar system. Here we present high-precision Si isotope data that show angrites are enriched in the heavy isotopes of Si relative to chondritic meteorites by 50–100 ppm/amu. Silicon is sufficiently volatile such that it may be isotopically fractionated during incomplete condensation or evaporative mass loss, but theoretical calculations and experimental results also predict isotope fractionation under specific conditions of metal–silicate differentiation. We show that the Si isotope composition of angrites cannot be explained by any plausible core formation scenario, but rather reflects isotope fractionation during impact-induced evaporation. Our results indicate planetesimals initially formed from volatile-rich material and were subsequently depleted in volatile elements during accretion. PMID:25404309

Herbivory by a Phloem-feeding insect inhibits floral volatile production.

Science.gov (United States)

Pareja, Martin; Qvarfordt, Erika; Webster, Ben; Mayon, Patrick; Pickett, John; Birkett, Michael; Glinwood, Robert

2012-01-01

There is extensive knowledge on the effects of insect herbivory on volatile emission from vegetative tissue, but little is known about its impact on floral volatiles. We show that herbivory by phloem-feeding aphids inhibits floral volatile emission in white mustard Sinapis alba measured by gas chromatographic analysis of headspace volatiles. The effect of the Brassica specialist aphid Lipaphis erysimi was stronger than the generalist aphid Myzus persicae and feeding by chewing larvae of the moth Plutella xylostella caused no reduction in floral volatile emission. Field observations showed no effect of L. erysimi-mediated floral volatile emission on the total number of flower visits by pollinators. Olfactory bioassays suggested that although two aphid natural enemies could detect aphid inhibition of floral volatiles, their olfactory orientation to infested plants was not disrupted. This is the first demonstration that phloem-feeding herbivory can affect floral volatile emission, and that the outcome of interaction between herbivory and floral chemistry may differ depending on the herbivore's feeding mode and degree of specialisation. The findings provide new insights into interactions between insect herbivores and plant chemistry.

Na, Rb and Cs partitioning between metal, silicate and sulfide: Implications for volatile depletion in terrestrial planets

Science.gov (United States)

Boujibar, A.; Fei, Y.; Du, Z.; Righter, K.; Bullock, E. S.

2017-12-01

Inner Solar System materials are known for their depletion in volatile elements, including the moderately volatile alkalis: Na, K, Rb, and Cs. The origin of this depletion is still uncertain, as several processes could have been involved, during the nebular condensation or planetary accretion. Volatile depletion is commonly estimated through comparison of alkali concentrations relatively to those of chondrites, assuming they remain in planetary mantles during core segregation. However, experimental studies show that substantial K can partition into metals that are enriched in sulfur and oxygen. Several models have also suggested that sulfides may have played an important role during episodes of sulfide segregation from a crystallizing magma ocean (sulfide matte) or accretion of S-rich planetary embryos. For Mercury, a sulfide layer could be present between core and mantle, due to immiscibility between Si-rich and S-rich metals. Therefore, here we investigate whether alkali elements (Na, Cs and Rb) could be partly sequestered in planetary cores during their differentiation. We conducted experiments at high pressure and temperature (1 to 5 GPa and up to 1900 °C) to determine partition coefficients of Na, Rb and Cs between metal and silicate. Our results show that pressure, temperature, sulfur and oxygen in metals enhance the partitioning of Na, Rb and Cs into metals, as previously found for K. For all three investigated alkalis (Na, Rb and Cs), we found a maximum partition coefficient of 1 between sulfides containing 13 wt% O and silicate melt. Therefore, S-rich cores or sulfide layers formed due to immiscibility in Fe-S-O systems could have acted as important geochemical reservoirs for alkali elements. Using our experimental data and different assumptions on initial bulk abundances, we evaluate volatile depletion in terrestrial planets, by comparing resulting mantle alkali concentrations after core segregation, with actual concentrations in the Earth's mantle.

Characterisation of selected volatile organic compounds in ...

African Journals Online (AJOL)

GCMS), was used to identify volatile compounds at three different temperatures. Fifty volatile compounds, inclusive of 14 acids, 14 alcohols, and 22 esters were identified and quantified in the two brands of indigenous banana beer samples. Only 12 ...

Can occupancy-abundance models be used to monitor wolf abundance?

Directory of Open Access Journals (Sweden)

M Cecilia Latham

Full Text Available Estimating the abundance of wild carnivores is of foremost importance for conservation and management. However, given their elusive habits, direct observations of these animals are difficult to obtain, so abundance is more commonly estimated from sign surveys or radio-marked individuals. These methods can be costly and difficult, particularly in large areas with heavy forest cover. As an alternative, recent research has suggested that wolf abundance can be estimated from occupancy-abundance curves derived from "virtual" surveys of simulated wolf track networks. Although potentially more cost-effective, the utility of this approach hinges on its robustness to violations of its assumptions. We assessed the sensitivity of the occupancy-abundance approach to four assumptions: variation in wolf movement rates, changes in pack cohesion, presence of lone wolves, and size of survey units. Our simulations showed that occupancy rates and wolf pack abundances were biased high if track surveys were conducted when wolves made long compared to short movements, wolf packs were moving as multiple hunting units as opposed to a cohesive pack, and lone wolves were moving throughout the surveyed landscape. We also found that larger survey units (400 and 576 km2 were more robust to changes in these factors than smaller survey units (36 and 144 km2. However, occupancy rates derived from large survey units rapidly reached an asymptote at 100% occupancy, suggesting that these large units are inappropriate for areas with moderate to high wolf densities (>15 wolves/1,000 km2. Virtually-derived occupancy-abundance relationships can be a useful method for monitoring wolves and other elusive wildlife if applied within certain constraints, in particular biological knowledge of the surveyed species needs to be incorporated into the design of the occupancy surveys. Further, we suggest that the applicability of this method could be extended by directly incorporating some of its

Variability in Abundances of Meteorites in the Ordovician

Science.gov (United States)

Heck, P. R.; Schmitz, B.; Kita, N.

2017-12-01

The knowledge of the flux of extraterrestrial material throughout Earth's history is of great interest to reconstruct the collisional evolution of the asteroid belt. Here, we present a review of our investigations of the nature of the meteorite flux to Earth in the Ordovician, one of the best-studied time periods for extraterrestrial matter in the geological record [1]. We base our studies on compositions of extraterrestrial chromite and chrome-spinel extracted by acid dissolution from condensed marine limestone from Sweden and Russia [1-3]. By analyzing major and minor elements with EDS and WDS, and three oxygen isotopes with SIMS we classify the recovered meteoritic materials. Today, the L and H chondrites dominate the meteorite and coarse micrometeorite flux. Together with the rarer LL chondrites they have a type abundance of 80%. In the Ordovician it was very different: starting from 466 Ma ago 99% of the flux was comprised of L chondrites [2]. This was a result of the collisional breakup of the parent asteroid. This event occurred close to an orbital resonance in the asteroid belt and showered Earth with >100x more L chondritic material than today during more than 1 Ma. Although the flux is much lower at present, L chondrites are still the dominant type of meteorites that fall today. Before the asteroid breakup event 467 Ma ago the three groups of ordinary chondrites had about similar abundances. Surprisingly, they were possibly surpassed in abundance by achondrites, materials from partially and fully differentiated asteroids [3]. These achondrites include HED meteorites, which are presumably fragments released during the formation of the Rheasilvia impact structure 1 Ga ago on asteroid 4 Vesta. The enhanced abundance of LL chondrites is possibly a result of the Flora asteroid family forming event at 1 Ga ago. The higher abundance of primitive achondrites was likely due to smaller asteroid family forming events that have not been identified yet but that did

Volatility of an Indian stock market: A random matrix approach

International Nuclear Information System (INIS)

Kulkarni, V.; Deo, N.

2006-07-01

We examine volatility of an Indian stock market in terms of aspects like participation, synchronization of stocks and quantification of volatility using the random matrix approach. Volatility pattern of the market is found using the BSE index for the three-year period 2000- 2002. Random matrix analysis is carried out using daily returns of 70 stocks for several time windows of 85 days in 2001 to (i) do a brief comparative analysis with statistics of eigenvalues and eigenvectors of the matrix C of correlations between price fluctuations, in time regimes of different volatilities. While a bulk of eigenvalues falls within RMT bounds in all the time periods, we see that the largest (deviating) eigenvalue correlates well with the volatility of the index, the corresponding eigenvector clearly shows a shift in the distribution of its components from volatile to less volatile periods and verifies the qualitative association between participation and volatility (ii) observe that the Inverse participation ratio for the last eigenvector is sensitive to market fluctuations (the two quantities are observed to anti correlate significantly) (iii) set up a variability index, V whose temporal evolution is found to be significantly correlated with the volatility of the overall market index. MIRAMAR (author)

Characterization of the bound volatile extract from baby kiwi (Actinidia arguta).

Science.gov (United States)

Garcia, Coralia V; Quek, Siew-Young; Stevenson, Ralph J; Winz, Robert A

2011-08-10

The glycosidically bound volatile fraction of baby kiwi ( Actinidia arguta ) was studied. Glycosidic precursors were isolated from juice by adsorption onto an Amberlite XAD-2 column. After enzymatic hydrolysis with Rapidase AR2000, the released aglycones were analyzed by GC-MS. Alcohols, terpenoids, and benzenoids were the most abundant compound classes. Aromatic compounds and norisoprenoids showed the highest concentrations. Major compounds were 2,5-dimethyl-4-hydroxy-3(2H)-furanone (Furaneol), benzyl alcohol, 3-hydroxy-β-damascone, hexanal, and (Z)-3-hexen-1-ol. Precursors of aroma compounds including benzoic acid, cinnamic acid, and coniferyl alcohol were also found. Eugenol, raspberry ketone, and 4-vinylguaiacol were identified for the first time in the fruit of an Actinidia species. The high concentration of 2,5-dimethyl-4-hydroxy-3(2H)-furanone in bound form (95.36 μg/kg) is particularly interesting and justifies further investigation.

The memory of volatility

Directory of Open Access Journals (Sweden)

Kai R. Wenger

2018-03-01

Full Text Available The focus of the volatility literature on forecasting and the predominance of theconceptually simpler HAR model over long memory stochastic volatility models has led to the factthat the actual degree of memory estimates has rarely been considered. Estimates in the literaturerange roughly between 0.4 and 0.6 - that is from the higher stationary to the lower non-stationaryregion. This difference, however, has important practical implications - such as the existence or nonexistenceof the fourth moment of the return distribution. Inference on the memory order is complicatedby the presence of measurement error in realized volatility and the potential of spurious long memory.In this paper we provide a comprehensive analysis of the memory in variances of international stockindices and exchange rates. On the one hand, we find that the variance of exchange rates is subject tospurious long memory and the true memory parameter is in the higher stationary range. Stock indexvariances, on the other hand, are free of low frequency contaminations and the memory is in the lowernon-stationary range. These results are obtained using state of the art local Whittle methods that allowconsistent estimation in presence of perturbations or low frequency contaminations.

Volatile organic carbon/air separation test using gas membranes

International Nuclear Information System (INIS)

King, C.V.; Kaschemekat, J.

1993-08-01

An estimated 900 metric tons of carbon tetrachloride were discharged to soil columns during the Plutonium Finishing Plant Operations at the Hanford Site. The largest percentage of this volatile organic compound was found in the vadose region of the 200 West Area. Using a Vacuum Extraction System, the volatile organic compound was drawn from the soil in an air mixture at a concentration of about 1,000 parts per million. The volatile organic compounds were absorbed from the air stream using granulated activated carbon canisters. A gas membrane separation system, developed by Membrane Technology and Research, Inc., was tested at the Vacuum Extraction System site to determine if the volatile organic compound load on the granulated activated carbon could be reduced. The Vacuum Extraction System condensed most of the volatile organic compound into liquid carbon tetrachloride and vented the residual gas stream into the granulated activated carbon. This system reduced the cost of operation about $5/kilogram of volatile organic compound removed

Changing volatility of U.S. annual tornado reports

Science.gov (United States)

Tippett, Michael K.

2014-10-01

United States (U.S.) tornado activity results in substantial loss of life and property damage each year. A simple measure of the U.S. tornado climatology is the average number of tornadoes per year. However, even this statistic is elusive because of nonstationary behavior due in large part to changes in reporting practices. Differencing of the annual report data results in a quantity without mean trends and whose standard deviation we denote as volatility, since it is an indication of the likely year-to-year variation in the number of tornadoes reported. While volatility changes detected prior to 2000 can be associated with known reporting practice changes, an increase in volatility in the 2000s across intensity levels cannot. A volatility increase is also seen in a tornado environment index which measures the favorability of atmospheric conditions to tornado activity, providing evidence that the recent increase in tornado report volatility is related to the physical environment.

Constraints on the Chemistry and Abundance of Hydrous Phases in Sub Continental Lithospheric Mantle: Implications for Mid-Lithospheric Discontinuities

Science.gov (United States)

Saha, S.; Dasgupta, R.; Fischer, K. M.; Mookherjee, M.

2017-12-01

The origins of a 2-10% reduction in seismic shear wave velocity (Vs) at depths of 60-160 km in sub continental lithospheric mantle (SCLM) regions, identified as the Mid Lithospheric Discontinuity (MLD) [e.g., 1] are highly debated [e.g., 2, 3]. One of the proposed explanations for MLDs is the presence of hydrous minerals such as amphibole and phlogopite at these depths [e.g., 2, 4, 5]. Although the stability and compositions of these phases in peridotite + H2O ± CO2 have been widely explored [e.g., 6], their composition and abundance as a function of permissible SCLM chemistry remain poorly understood. We have compiled phase equilibria experiments conducted over a range of pressure (0.5-8 GPa), temperature (680-1300 °C), major element peridotite compositions, and volatiles (H2O: 0.05-13.79 wt.% and CO2: 0.25-5.3 wt.%). The goal was to constrain how compositional parameters such as CaO and alkali/H2O affect the chemistry and abundance of amphibole and phlogopite. We observe that the abundance of amphibole increases with CaO content and decreasing alkali/H2O. The abundance of phlogopite varies directly with K2O content. Unlike phlogopite compositions that remain consistent, amphibole compositions show variability (pargastitic to K-richterite) depending on bulk CaO and Na2O. Mineral modes, obtained by mass balance on a melt/fluid free basis, were used to calculate aggregate shear wave velocity, Vs for the respective assemblages [e.g., 7] and compared with absolute values observed at MLD depths [e.g., 8]. Vs shows a strong inverse correlation with phlogopite and amphibole modes (particularly where phlogopite is absent). For the Mg# range of cratonic xenoliths, 5-10% phlogopite at MLD depths can match the observed Vs values, while CaO contents in cratonic xenoliths limit the amphibole abundance to 10%, which is lower than previous estimates based on heat flow calculations [e.g., 4]. The modes of hydrous and other phases and corresponding Vs values could be used to

Mutual fund volatility timing and management fees

NARCIS (Netherlands)

Giambona, E.; Golec, J.

2009-01-01

This paper shows that compensation incentives partly drive fund managers’ market volatility timing strategies. Larger incentive management fees lead to less counter-cyclical or more pro-cyclical volatility timing. But fund styles or aggregate fund flows could also account for this relation;

Volatility jumps and their economic determinants

DEFF Research Database (Denmark)

Caporin, Massimiliano; Rossi, Eduardo; Santucci de Magistris, Paolo

that there is a positive probability of jumps in volatility. A common factor in the volatility jumps is shown to be related to a set of financial covariates (such as variance risk premium, S&P500 volume, credit-default swap, and federal fund rates). The credit-default swap on US banks and variance risk premium have...... predictive power on expected jump moves, thus confirming the common interpretation that sudden and large increases in equity volatility can be anticipated by credit deterioration of the US bank sector as well as changes in the market expectations of future risks. Finally, the model is extended to incorporate...... the credit-default swap and the variance risk premium in the dynamics of the jump size and intensity....

Volatilization of gasoline from soil

International Nuclear Information System (INIS)

Arthus, P.

1993-05-01

Gasoline contaminated soil threatens water resources and air quality. The extent of the threat depends on gasoline behavior in soil, which is affected by various mechanisms such as volatilization. To quantify volatilization, gasoline spills were simulated in the laboratory using a synthetic gasoline and three dry soils. Total gasoline and individual gasoline compound concentrations in soil were monitored as a function of depth and time. The time to reduce overall gasoline concentration in coarse sand, sandy loam, and silt loam to 40% of initial concentration, averaged between surface and a 200-mm depth, ranged from 0.25 d to 10 d. A wicking phenomenon which contributed to gasoline flux toward the atmosphere was indicated by behavior of a low-volatility gasoline compound. Based on separate wicking experiments, this bulk immiscible movement was estimated at an upward velocity of 0.09 m/d for Delhi sandy loam and 0.05 m/d for Elora silt loam. 70 refs., 24 figs., 34 tabs

Stock price dynamics and option valuations under volatility feedback effect

Science.gov (United States)

Kanniainen, Juho; Piché, Robert

2013-02-01

According to the volatility feedback effect, an unexpected increase in squared volatility leads to an immediate decline in the price-dividend ratio. In this paper, we consider the properties of stock price dynamics and option valuations under the volatility feedback effect by modeling the joint dynamics of stock price, dividends, and volatility in continuous time. Most importantly, our model predicts the negative effect of an increase in squared return volatility on the value of deep-in-the-money call options and, furthermore, attempts to explain the volatility puzzle. We theoretically demonstrate a mechanism by which the market price of diffusion return risk, or an equity risk-premium, affects option prices and empirically illustrate how to identify that mechanism using forward-looking information on option contracts. Our theoretical and empirical results support the relevance of the volatility feedback effect. Overall, the results indicate that the prevailing practice of ignoring the time-varying dividend yield in option pricing can lead to oversimplification of the stock market dynamics.

Reproductive endocrine patterns and volatile urinary compounds of Arctictis binturong: discovering why bearcats smell like popcorn

Science.gov (United States)

Greene, Lydia K.; Wallen, Timothy W.; Moresco, Anneke; Goodwin, Thomas E.; Drea, Christine M.

2016-06-01

Members of the order Carnivora rely on urinary scent signaling, particularly for communicating about reproductive parameters. Here, we describe reproductive endocrine patterns in relation to urinary olfactory cues in a vulnerable and relatively unknown viverrid—the binturong ( Arctictis binturong). Female binturongs are larger than and dominate males, and both sexes engage in glandular and urinary scent marking. Using a large ( n = 33), captive population, we collected serum samples to measure circulating sex steroids via enzyme immunoassay and urine samples to assay volatile chemicals via gas chromatography-mass spectrometry. Male binturongs had expectedly greater androgen concentrations than did females but, more unusually, had equal estrogen concentrations, which may be linked to male deference. Males also expressed a significantly richer array of volatile chemical compounds than did females. A subset of these volatile chemicals resisted decay at ambient temperatures, potentially indicating their importance as long-lasting semiochemicals. Among these compounds was 2-acetyl-1-pyrroline (2-AP), which is typically produced at high temperatures by the Maillard reaction and is likely to be responsible for the binturong's characteristic popcorn aroma. 2-AP, the only compound expressed by all of the subjects, was found in greater abundance in males than females and was significantly and positively related to circulating androstenedione concentrations in both sexes. This unusual compound may have a more significant role in mammalian semiochemistry than previously appreciated. Based on these novel data, we suggest that hormonal action and potentially complex chemical reactions mediate communication of the binturong's signature scent and convey information about sex and reproductive state.

Hedging electricity price volatility using nuclear power

International Nuclear Information System (INIS)

Mari, Carlo

2014-01-01

Highlights: • Nuclear power is an important asset to reduce the volatility of electricity prices. • Unpredictability of fossil fuels and carbon prices makes power prices very volatile. • The dynamics of fossil fuels and carbon prices is described by Brownian motions. • LCOE values, volatilities and correlations are obtained via Monte Carlo simulations. • Optimal portfolios of generating technologies are get using a mean–variance approach. - Abstract: The analysis presented in this paper aims to put in some evidence the role of nuclear power as hedging asset against the volatility of electricity prices. The unpredictability of natural gas and coal market prices as well as the uncertainty in environmental policies may affect power generating costs, thus enhancing volatility in electricity market prices. The nuclear option, allowing to generate electricity without carbon emissions, offers the possibility to reduce the volatility of electricity prices through optimal diversification of power generating technologies. This paper provides a methodological scheme to plan well diversified “portfolios” of generating capacity that minimize the electricity price risk induced by random movements of fossil fuels market prices and by unpredictable fluctuations of carbon credits prices. The analysis is developed within a stochastic environment in which the dynamics of fuel prices as well as the dynamics of carbon credits prices is assumed to evolve in time according to well defined Brownian processes. Starting from market data and using Monte Carlo techniques to simulate generating cost values, the hedging argument is developed by selecting optimal portfolio of power generating technologies using a mean–variance approach

Herbivory by a Phloem-feeding insect inhibits floral volatile production.

Directory of Open Access Journals (Sweden)

Martin Pareja

Full Text Available There is extensive knowledge on the effects of insect herbivory on volatile emission from vegetative tissue, but little is known about its impact on floral volatiles. We show that herbivory by phloem-feeding aphids inhibits floral volatile emission in white mustard Sinapis alba measured by gas chromatographic analysis of headspace volatiles. The effect of the Brassica specialist aphid Lipaphis erysimi was stronger than the generalist aphid Myzus persicae and feeding by chewing larvae of the moth Plutella xylostella caused no reduction in floral volatile emission. Field observations showed no effect of L. erysimi-mediated floral volatile emission on the total number of flower visits by pollinators. Olfactory bioassays suggested that although two aphid natural enemies could detect aphid inhibition of floral volatiles, their olfactory orientation to infested plants was not disrupted. This is the first demonstration that phloem-feeding herbivory can affect floral volatile emission, and that the outcome of interaction between herbivory and floral chemistry may differ depending on the herbivore's feeding mode and degree of specialisation. The findings provide new insights into interactions between insect herbivores and plant chemistry.

The volatile compound BinBase mass spectral database.

Science.gov (United States)

Skogerson, Kirsten; Wohlgemuth, Gert; Barupal, Dinesh K; Fiehn, Oliver

2011-08-04

Volatile compounds comprise diverse chemical groups with wide-ranging sources and functions. These compounds originate from major pathways of secondary metabolism in many organisms and play essential roles in chemical ecology in both plant and animal kingdoms. In past decades, sampling methods and instrumentation for the analysis of complex volatile mixtures have improved; however, design and implementation of database tools to process and store the complex datasets have lagged behind. The volatile compound BinBase (vocBinBase) is an automated peak annotation and database system developed for the analysis of GC-TOF-MS data derived from complex volatile mixtures. The vocBinBase DB is an extension of the previously reported metabolite BinBase software developed to track and identify derivatized metabolites. The BinBase algorithm uses deconvoluted spectra and peak metadata (retention index, unique ion, spectral similarity, peak signal-to-noise ratio, and peak purity) from the Leco ChromaTOF software, and annotates peaks using a multi-tiered filtering system with stringent thresholds. The vocBinBase algorithm assigns the identity of compounds existing in the database. Volatile compound assignments are supported by the Adams mass spectral-retention index library, which contains over 2,000 plant-derived volatile compounds. Novel molecules that are not found within vocBinBase are automatically added using strict mass spectral and experimental criteria. Users obtain fully annotated data sheets with quantitative information for all volatile compounds for studies that may consist of thousands of chromatograms. The vocBinBase database may also be queried across different studies, comprising currently 1,537 unique mass spectra generated from 1.7 million deconvoluted mass spectra of 3,435 samples (18 species). Mass spectra with retention indices and volatile profiles are available as free download under the CC-BY agreement (http://vocbinbase.fiehnlab.ucdavis.edu). The Bin

The volatile compound BinBase mass spectral database

Directory of Open Access Journals (Sweden)

Barupal Dinesh K

2011-08-01

Full Text Available Abstract Background Volatile compounds comprise diverse chemical groups with wide-ranging sources and functions. These compounds originate from major pathways of secondary metabolism in many organisms and play essential roles in chemical ecology in both plant and animal kingdoms. In past decades, sampling methods and instrumentation for the analysis of complex volatile mixtures have improved; however, design and implementation of database tools to process and store the complex datasets have lagged behind. Description The volatile compound BinBase (vocBinBase is an automated peak annotation and database system developed for the analysis of GC-TOF-MS data derived from complex volatile mixtures. The vocBinBase DB is an extension of the previously reported metabolite BinBase software developed to track and identify derivatized metabolites. The BinBase algorithm uses deconvoluted spectra and peak metadata (retention index, unique ion, spectral similarity, peak signal-to-noise ratio, and peak purity from the Leco ChromaTOF software, and annotates peaks using a multi-tiered filtering system with stringent thresholds. The vocBinBase algorithm assigns the identity of compounds existing in the database. Volatile compound assignments are supported by the Adams mass spectral-retention index library, which contains over 2,000 plant-derived volatile compounds. Novel molecules that are not found within vocBinBase are automatically added using strict mass spectral and experimental criteria. Users obtain fully annotated data sheets with quantitative information for all volatile compounds for studies that may consist of thousands of chromatograms. The vocBinBase database may also be queried across different studies, comprising currently 1,537 unique mass spectra generated from 1.7 million deconvoluted mass spectra of 3,435 samples (18 species. Mass spectra with retention indices and volatile profiles are available as free download under the CC-BY agreement (http

Capital mobility and macroeconomic volatility: evidence from Greece

OpenAIRE

Anastasios, Pappas

2010-01-01

This paper focuses on the impact of full capital account liberalization on macroeconomic volatility in Greece. According to the standard neoclassical model, such liberalization is to be desired because, among other advantages, it may reduce macroeconomic volatility. The link between macroeconomic volatility and capital account openness in the Greek economy is investigated by applying a simple three-month rolling standard deviation of real GDP growth and real final (total) consumption growth c...

Chemically-resolved volatility measurements of organic aerosol fom different sources.

Science.gov (United States)

Huffman, J A; Docherty, K S; Mohr, C; Cubison, M J; Ulbrich, I M; Ziemann, P J; Onasch, T B; Jimenez, J L

2009-07-15

A newly modified fast temperature-stepping thermodenuder (TD) was coupled to a High Resolution Time-of-Flight Aerosol Mass Spectrometer for rapid determination of chemically resolved volatility of organic aerosols (OA) emitted from individual sources. The TD-AMS system was used to characterize primary OA (POA) from biomass burning, trash burning surrogates (paper and plastic), and meat cooking as well as chamber-generated secondary OA (SOA) from alpha-pinene and gasoline vapor. Almost all atmospheric models represent POA as nonvolatile, with no allowance for evaporation upon heating or dilution, or condensation upon cooling. Our results indicate that all OAs observed show semivolatile behavior and that most POAs characterized here were at least as volatile as SOA measured in urban environments. Biomass-burning OA (BBOA) exhibited a wide range of volatilities, but more often showed volatility similar to urban OA. Paper-burning resembles some types of BBOA because of its relatively high volatility and intermediate atomic oxygen-to-carbon (O/C) ratio, while meat-cooking OAs (MCOA) have consistently lower volatility than ambient OA. Chamber-generated SOA under the relatively high concentrations used intraditional experiments was significantly more volatile than urban SOA, challenging extrapolation of traditional laboratory volatility measurements to the atmosphere. Most OAs sampled show increasing O/C ratio and decreasing H/C (hydrogen-to-carbon) ratio with temperature, further indicating that more oxygenated OA components are typically less volatile. Future experiments should systematically explore a wider range of mass concentrations to more fully characterize the volatility distributions of these OAs.

Ammonia volatilization from coated urea forms

Directory of Open Access Journals (Sweden)

Carlos Antonio Costa do Nascimento

2013-08-01

Full Text Available Nitrogen fertilization is a major component of the cost of agricultural production, due to the high cost and low efficiency of fertilizers. In the case of urea, the low efficiency is mainly due to losses by volatilization, which are more pronounced in cultivation systems in which plant residues are left on the soil. The objective of this work was to compare the influence of urea coated with sulfur or boric acid and copper sulfate with conventional N fertilizers on N volatilization losses in sugar cane harvested after stubble burning. The sources urea, sulfur-coated urea, urea coated with boric acid and copper sulfate, as well as nitrate and ammonium sulfate, were tested at amounts containing N rates of 120 kg ha-1 N. The integration of new technologies in urea fertilization can reduce N losses by volatilization. These losses were most reduced when using nitrate and ammonium sulfate. The application of a readily acidified substance (boric acid to urea was more efficient in reducing volatilization losses and nutrient removal by sugar cane than that of a substance with gradual acidification (elemental sulfur.

The electoral volatility in Serbia: Comparison and explanation

Directory of Open Access Journals (Sweden)

Antonić Slobodan

2005-01-01

Full Text Available In the first part of this article the electoral volatility in Serbia is compared to those in other countries. The Pedersen’s Index for Serbia from 1990 to 2003 is 19.6, which means there is high electoral volatility. However, compared to other countries in transition, the volatility in Serbia turns out to be average. Therefore, I conclude that the causes of high volatility in Serbia could not be specific, but similar to the reasons in other post-communist countries. In the second part, I analyze the general reasons for the increased volatility. They are: the large number of parties participating in political life, and insufficient time, passed since the restoration of multiparty elections, for the voters to become more seriously tied to the parties, or for the parties to become socially anchored. In the third part, I analyze the particular causes of the increased volatility that are specific, first of all, for Serbia and other post-communist societies. They are: the fast change of social structure, which leads to a general feeling of social and personal insecurity, as well as the widespread dissatisfaction with the gap between the increase of social inequality and the number of social winners, which increases the frequency of protest voting. At the end, I conclude that, in time, some of these factors would probably lose their significance, so the volatility in Serbia would decrease. However, a noticeable decrease could hardly be expected during the next ten years at least.

Modelling oil price volatility with structural breaks

International Nuclear Information System (INIS)

Salisu, Afees A.; Fasanya, Ismail O.

2013-01-01

In this paper, we provide two main innovations: (i) we analyze oil prices of two prominent markets namely West Texas Intermediate (WTI) and Brent using the two recently developed tests by Narayan and Popp (2010) and Liu and Narayan, 2010 both of which allow for two structural breaks in the data series; and (ii) the latter method is modified to include both symmetric and asymmetric volatility models. We identify two structural breaks that occur in 1990 and 2008 which coincidentally correspond to the Iraqi/Kuwait conflict and the global financial crisis, respectively. We find evidence of persistence and leverage effects in the oil price volatility. While further extensions can be pursued, the consideration of asymmetric effects as well as structural breaks should not be jettisoned when modelling oil price volatility. - Highlights: ► We analyze oil price volatility using NP (2010) and LN (2010) tests. ► We modify the LN (2010) to account for leverage effects in oil price. ► We find two structural breaks that reflect major global crisis in the oil market. ► We find evidence of persistence and leverage effects in oil price volatility. ► Leverage effects and structural breaks are fundamental in oil price modelling.

Multifractal in Volatility of Family Business Stocks Listed on Casablanca STOCK Exchange

Science.gov (United States)

Lahmiri, Salim

In this paper, we check for existence of multifractal in volatility of Moroccan family business stock returns and in volatility of Casablanca market index returns based on multifractal detrended fluctuation analysis (MF-DFA) technique. Empirical results show strong evidence of multifractal characteristics in volatility series of both family business stocks and market index. In addition, it is found that small variations in volatility of family business stocks are persistent, whilst small variations in volatility of market index are anti-persistent. However, large variations in family business volatility and market index volatility are both anti-persistent. Furthermore, multifractal spectral analysis based results show strong evidence that volatility in Moroccan family business companies exhibits more multifractality than volatility in the main stock market. These results may provide insightful information for risk managers concerned with family business stocks.

Option pricing under stochastic volatility: the exponential Ornstein–Uhlenbeck model

International Nuclear Information System (INIS)

Perelló, Josep; Masoliver, Jaume; Sircar, Ronnie

2008-01-01

We study the pricing problem for a European call option when the volatility of the underlying asset is random and follows the exponential Ornstein–Uhlenbeck model. The random diffusion model proposed is a two-dimensional market process that takes a log-Brownian motion to describe price dynamics and an Ornstein–Uhlenbeck subordinated process describing the randomness of the log-volatility. We derive an approximate option price that is valid when (i) the fluctuations of the volatility are larger than its normal level, (ii) the volatility presents a slow driving force, toward its normal level and, finally, (iii) the market price of risk is a linear function of the log-volatility. We study the resulting European call price and its implied volatility for a range of parameters consistent with daily Dow Jones index data

Anomalous behavior of tellurium abundances

Energy Technology Data Exchange (ETDEWEB)

Cohen, B L

1984-01-01

The cosmic abundance of Te is larger than for any element with atomic number greater than 40, but it is one of the least abundant elements in the earth's lithosphere and it is one of the five elements never reported in sea water. On the other hand, it is the fourth most abundant element in the human body (after Fe, Zn and Rb), and is unusually abundant in human food. It is shown that the high abundance in human food combined with the low abundance in soil requires that it be picked up by plant roots very much more efficiently than any other trace element.

Some recent developments in stochastic volatility modelling

DEFF Research Database (Denmark)

Barndorff-Nielsen, Ole Eiler; Nicolato, Elisa; Shephard, N.

2002-01-01

This paper reviews and puts in context some of our recent work on stochastic volatility (SV) modelling for financial economics. Here our main focus is on: (i) the relationship between subordination and SV, (ii) OU based volatility models, (iii) exact option pricing, (iv) realized power variation...

Volatility transmission and patterns in Bund futures

NARCIS (Netherlands)

Ph.H.B.F. Franses (Philip Hans); R. van Ieperen; A.J. Menkveld (Bert); P. Kofman (Paul); M.P.E. Martens (Martin)

1997-01-01

textabstractWe analyze intraday volatility behavior for the Bund futures contract that is traded simultaneously at two competing exchanges. We investigate the transmission of volatility between the exchanges. We find that the lead/lag relations are restricted to a few minutes and do not reveal a

Order flow and volatility: An empirical investigation

NARCIS (Netherlands)

Opschoor, A.; Taylor, N.; van der Wel, M.; van Dijk, D.

2014-01-01

We study the relationship between order flow and volatility. To this end we develop a comprehensive framework that simultaneously controls for the effects of macro announcements and order flow on prices and the effect of macro announcements on volatility. Using high-frequency 30-year U.S. Treasury

Volatile compound diversity and conserved alarm behaviour in Triatoma dimidiata.

Science.gov (United States)

May-Concha, Irving; Rojas, Julio C; Cruz-López, Leopoldo; Ibarra-Cerdeña, Carlos N; Ramsey, Janine M

2015-02-06

Triatoma dimidiata (Latreille) is a key vector complex of Trypanosoma cruzi, etiologic agent of Chagas disease, as it spans North, Central, and South America. Although morphological and genetic studies clearly indicate existence of at least five clades within the species, there has been no robust or systematic revision, or appropriate nomenclature change for species within the complex. Three of the clades (haplogroups) are distributed in Mexico, and recent evidence attests to dispersal of clades across previously "presumed" monotypic geographic regions. Evidence of niche conservatism among sister species of this complex suggests that geographic dispersal is possible for non-sympatric populations, although no information is available on the behavioural aspects of potential interclade interactions, for instance whether differentiation of chemical signaling or response to these signals could impede communication among the haplogroups. Volatiles emitted by disturbed bugs, Brindley's (BGs), and metasternal (MGs) glands were identified using solid-phase micro-extraction (SPME) and gas chromatography coupled mass spectrometry (GC-MS). Volatile compounds emitted by BGs and MGs, and those secreted by disturbed nymphs and adults, of the three Mexican T. dimidiata haplogroups were tested for avoidance behaviour by conspecific nymphs and adults using an olfactometer. Triatoma dimidiata haplogroups all have three age-related alarm responses: absence of response by early stage nymphs, stage-specific response by 4-5th stage nymphs, and a shared 4-5th nymph and adult response to adult compounds. Disturbed bugs released 15 to 24 compounds depending on the haplogroup, among which were three pyrazines, the first report of these organoleptics in Triatominae. Isobutyric acid from BGs was the most abundant molecule in the response in all haplogroups, in addition to 15 (h1) to 21 (h2 and h3) MG compounds. Avoidance behaviour of disturbed bugs and volatiles emitted by BGs were haplogroup

Determinants of abundance and effects of blood-sucking flying insects in the nest of a hole-nesting bird.

Science.gov (United States)

Tomás, Gustavo; Merino, Santiago; Martínez-de la Puente, Josué; Moreno, Juan; Morales, Judith; Lobato, Elisa

2008-05-01

Compared to non-flying nest-dwelling ectoparasites, the biology of most species of flying ectoparasites and its potential impact on avian hosts is poorly known and rarely, if ever, reported. In this study we explore for the first time the factors that may affect biting midge (Diptera: Ceratopogonidae) and black fly (Diptera: Simuliidae) abundances in the nest cavity of a bird, the hole-nesting blue tit Cyanistes caeruleus, and report their effects on adults and nestlings during reproduction. The abundance of biting midges was positively associated with nest mass, parental provisioning effort and abundance of blowflies and black flies, while negatively associated with nestling condition. Furthermore, a medication treatment to reduce blood parasitaemias in adult birds revealed that biting midges were more abundant in nests of females whose blood parasitaemias were experimentally reduced. This finding would be in accordance with these insect vectors attacking preferentially uninfected or less infected hosts to increase their own survival. The abundance of black flies in the population was lower than that of biting midges and increased in nests with later hatching dates. No significant effect of black fly abundance on adult or nestling condition was detected. Blood-sucking flying insects may impose specific, particular selection pressures on their hosts and more research is needed to better understand these host-parasite associations.

21 CFR 573.914 - Salts of volatile fatty acids.

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Salts of volatile fatty acids. 573.914 Section 573... Food Additive Listing § 573.914 Salts of volatile fatty acids. (a) Identity. The food additive is a... contains ammonium or calcium salts of volatile fatty acids and shall conform to the following...

The Role of Implied Volatility in Forecasting Future Realized Volatility and Jumps in Foreign Exchange, Stock and Bond Markets

DEFF Research Database (Denmark)

Christensen, Bent Jesper

We study the forecasting of future realized volatility in the stock, bond, and foreign exchange markets, as well as the continuous sample path and jump components of this, from variables in the information set, including implied volatility backed out from option prices. Recent nonparametric...

Networks of volatility spillovers among stock markets

Science.gov (United States)

Baumöhl, Eduard; Kočenda, Evžen; Lyócsa, Štefan; Výrost, Tomáš

2018-01-01

In our network analysis of 40 developed, emerging and frontier stock markets during the 2006-2014 period, we describe and model volatility spillovers during both the global financial crisis and tranquil periods. The resulting market interconnectedness is depicted by fitting a spatial model incorporating several exogenous characteristics. We document the presence of significant temporal proximity effects between markets and somewhat weaker temporal effects with regard to the US equity market - volatility spillovers decrease when markets are characterized by greater temporal proximity. Volatility spillovers also present a high degree of interconnectedness, which is measured by high spatial autocorrelation. This finding is confirmed by spatial regression models showing that indirect effects are much stronger than direct effects; i.e., market-related changes in 'neighboring' markets (within a network) affect volatility spillovers more than changes in the given market alone, suggesting that spatial effects simply cannot be ignored when modeling stock market relationships. Our results also link spillovers of escalating magnitude with increasing market size, market liquidity and economic openness.

A whiff of death: fatal volatile solvent inhalation abuse.

Science.gov (United States)

Steffee, C H; Davis, G J; Nicol, K K

1996-09-01

Inhalation abuse of volatile solvents, previously known generically as "glue sniffing," is typically pursued by adolescents. A wide range of legal, easily obtained products containing volatile substances are available for abuse. We report two illustrative cases of fatal volatile substance abuse: gasoline sniffing in a 20-year-old man and aerosol propellant gas inhalation (aerosol air freshener) in a 16-year-old girl with underlying reactive airway disease. Although the ratio of deaths to nonfatal inhalation escapades is extremely low, volatile solvent abuse carries the risk of sudden death due to cardiac arrest after a dysrhythmia or vasovagal event, central nervous system respiratory depression, hypoxia and hypercapnia due to the techniques of inhalation, and other mechanisms. Investigation of the patient's substance abuse history, examination of the scene of death, and special toxicologic analyses are critical to identifying volatile substance inhalation abuse as the cause of death because anatomic autopsy findings will typically be nonspecific. Above all, physicians must suspect the diagnosis of volatile substance inhalation abuse, especially in any case of sudden death involving an otherwise healthy young person.

Volatiles from roasted byproducts of the poultry-processing industry.

Science.gov (United States)

Wettasinghe, M; Vasanthan, T; Temelli, F; Swallow, K

2000-08-01

Volatiles of roasted chicken breast muscle and byproducts, such as backbones, breastbones, spent bones, and skin, were investigated. Total volatile concentrations ranged from 2030 ppb in the roasted backbones to 4049 ppb in the roasted skin. The major classes of volatile compounds detected in roasted samples were aldehydes (648-1532 ppb) and alcohols (336-1006 ppb). Nitrogen- and/or sulfur-containing compounds were also detected in appreciable quantities (161-706 ppb) in all samples. For all samples, hexanal and 2-methyl-2-buten-1-ol were dominant among the aldehydes and alcohols, respectively. Among the nitrogen- and sulfur-containing compounds, Maillard reaction products, such as tetrahydropyridazines, piperidines, and thiazoles, were the major contributors to the total volatile content in all samples. The composition of volatiles observed in roasted byproducts was markedly different from that of the roasted breast muscle. Therefore, the blending of the byproducts in appropriate proportions or blending of volatile flavor extracts from different byproducts may be necessary to obtain an aroma that mimics roasted chicken aroma.

Reducing the negative sensory impact of volatile phenols in red wine with different chitosans: Effect of structure on efficiency.

Science.gov (United States)

Filipe-Ribeiro, Luís; Cosme, Fernanda; Nunes, Fernando M

2018-03-01

"Brett character" is a negative sensory attribute acquired by red wines when contaminating Dekkera/Brettanomyces yeasts produce 4-ethylphenol and 4-ethylguaiacol, known as volatile phenols (VPs), from cinnamic acid precursors. In this study, chitins and chitosans with different structural features, namely deacetylation degree (5-91%) and molecular weight (24-466kDa) were used for the reduction of this sensory defect. Chitins and chitosans decreased 7-26% of the headspace abundance of VPs without changing their amounts in wines. The efficiency of reduction increased with the deacetylation degree and applied dose. Reduction of headspace abundance of VPs by chitosans enabled significant decreases in the negative phenolic and bitterness attributes and increased positive fruity and floral attributes. Results show that chitosan with high deacetylation degrees, including fungal chitosan, which is already approved for use in wines, is an efficient approach for reducing the negative sensory impact of VPs in red wines. Copyright © 2017 Elsevier Ltd. All rights reserved.

Volatility Spillover in Chinese Steel Markets

Science.gov (United States)

Fang, Wen

2018-03-01

This paper examines volatility spillover in Chinese steel markets by comparing spillover effects before and after steel futures market established and finds some interesting change. Volatility spillover method based on multi-GARCH model are proposed. The results show that there is significant proof for spillover effects from B2B electronic market to spot market, and two-way effects between futures and spot market. Market policy planners and practitioners could make decisions according to the master of spillovers. We also find that B2B e-market and futures market can both provide efficient protection against steel price volatility risk, B2B e-market offer a broad-based platform for trading steel commodities over time and space since e-market role in information flow process is dominant.

Gas Chromatographic-Ion Trap Mass Spectrometric Analysis of Volatile Organic Compounds by Ion-Molecule Reactions Using the Electron-Deficient Reagent Ion CCl{3/+}

Science.gov (United States)

Wang, Cheng-Zhong; Su, Yue; Wang, Hao-Yang; Guo, Yin-Long

2011-10-01

When using tetrachloromethane as the reagent gas in gas chromatography-ion trap mass spectrometry equipped with hybrid ionization source, the cation CCl{3/+} was generated in high abundance and further gas-phase experiments showed that such an electron-deficient reagent ion CCl{3/+} could undergo interesting ion-molecule reactions with various volatile organic compounds, which not only present some informative gas-phase reactions, but also facilitate qualitative analysis of diverse volatile compounds by providing unique mass spectral data that are characteristic of particular chemical structures. The ion-molecule reactions of the reagent ion CCl{3/+} with different types of compounds were studied, and results showed that such reactions could give rise to structurally diagnostic ions, such as [M + CCl3 - HCl]+ for aromatic hydrocarbons, [M - OH]+ for saturated cyclic ether, ketone, and alcoholic compounds, [M - H]+ ion for monoterpenes, M·+ for sesquiterpenes, [M - CH3CO]+ for esters, as well as the further fragment ions. The mechanisms of ion-molecule reactions of aromatic hydrocarbons, aliphatic ketones and alcoholic compounds with the reagent ion CCl{3/+} were investigated and proposed according to the information provided by MS/MS experiments and theoretical calculations. Then, this method was applied to study volatile organic compounds in Dendranthema indicum var. aromaticum and 20 compounds, including monoterpenes and their oxygen-containing derivatives, aromatic hydrocarbon and sesquiterpenes were identified using such ion-molecule reactions. This study offers a perspective and an alternative tool for the analysis and identification of various volatile compounds.

Molecular abundances and C/O ratios in chemically evolving planet-forming disk midplanes

Science.gov (United States)

Eistrup, Christian; Walsh, Catherine; van Dishoeck, Ewine F.

2018-05-01

Context. Exoplanet atmospheres are thought be built up from accretion of gas as well as pebbles and planetesimals in the midplanes of planet-forming disks. The chemical composition of this material is usually assumed to be unchanged during the disk lifetime. However, chemistry can alter the relative abundances of molecules in this planet-building material. Aims: We aim to assess the impact of disk chemistry during the era of planet formation. This is done by investigating the chemical changes to volatile gases and ices in a protoplanetary disk midplane out to 30 AU for up to 7 Myr, considering a variety of different conditions, including a physical midplane structure that is evolving in time, and also considering two disks with different masses. Methods: An extensive kinetic chemistry gas-grain reaction network was utilised to evolve the abundances of chemical species over time. Two disk midplane ionisation levels (low and high) were explored, as well as two different makeups of the initial abundances ("inheritance" or "reset"). Results: Given a high level of ionisation, chemical evolution in protoplanetary disk midplanes becomes significant after a few times 105 yr, and is still ongoing by 7 Myr between the H2O and the O2 icelines. Inside the H2O iceline, and in the outer, colder regions of the disk midplane outside the O2 iceline, the relative abundances of the species reach (close to) steady state by 7 Myr. Importantly, the changes in the abundances of the major elemental carbon and oxygen-bearing molecules imply that the traditional "stepfunction" for the C/O ratios in gas and ice in the disk midplane (as defined by sharp changes at icelines of H2O, CO2 and CO) evolves over time, and cannot be assumed fixed, with the C/O ratio in the gas even becoming smaller than the C/O ratio in the ice. In addition, at lower temperatures (C/O ratios of exoplanets to where and how the atmospheres have formed in a disk midplane, chemical evolution needs to be considered and

Students with Autism Spectrum Disorder and Their Parents in the Transition into Higher Education: Impact on Dynamics in the Parent-Child Relationship.

Science.gov (United States)

Van Hees, Valérie; Roeyers, Herbert; De Mol, Jan

2018-05-02

This study examined how 34 senior students and first-year college students with autism spectrum disorder, their mothers (n = 34) and fathers (n = 26) navigate the higher education transition, and how this context impacts on dynamics in the parent-child relationships. Semi-structured interviews were analyzed based on grounded theory and dyadic analysis principles. Both parties were confronted with an abundance of challenges and experienced strong feelings of ambivalence, stress and anxiety. Differences in perspectives occurred regarding the construction of adulthood, the acquisition of autonomy, disclosure and subscribing to support services. These differences caused tensions in the parent-child relationship, hindering the transformation of the relationship into an adult-like mutual relationship. Clinical implications are extrapolated on the basis of these findings.

Volatility

Directory of Open Access Journals (Sweden)

María Sánchez

2016-11-01

Full Text Available The action consists of moving with small kicks a tin of cola refresh -without Brand-from a point of the city up to other one. During the path I avoid bollards, the slope differences between sidewalks, pedestrians, parked motorcycles, etc. Volatility wants to say exactly that the money is getting lost. That the money is losing by gentlemen and by ladies who are neither financial sharks, nor big businessmen… or similarly, but ingenuous people, as you or as me, who walk down the street.

THE CARBON MONOXIDE ABUNDANCE IN COMET 103P/HARTLEY 2 DURING THE EPOXI FLYBY

International Nuclear Information System (INIS)

Weaver, H. A.; Dello Russo, N.; Feldman, P. D.; A'Hearn, M. F.; Stern, S. A.

2011-01-01

We report the detection of several emission bands in the CO Fourth Positive Group from comet 103P/Hartley 2 during ultraviolet spectroscopic observations from the Hubble Space Telescope on 2010 November 4 near the time of closest approach by NASA's EPOXI spacecraft. The derived CO/H 2 O ratio is 0.15%-0.45%, which places 103P/Hartley 2 among the most CO-depleted comets. Apparently this highly volatile species, whose abundance varies by a factor of ∼50 among the comets observed to date, does not play a major role in producing the strong and temporally variable activity in 103P/Hartley 2. The CO emissions varied by ∼30% between our two sets of observations, apparently in phase with the temporal variability measured for several gases and dust by other observers. The low absolute abundance of CO in 103P/Hartley 2 suggests several possibilities: the nucleus formed in a region of the solar nebula that was depleted in CO or too warm to retain much CO ice, repeated passages through the inner solar system have substantially depleted the comet's primordial CO reservoir, or any CO still in the nucleus is buried below the regions that contribute significantly to the coma.

Financial sector development, economic volatility and shocks in sub-Saharan Africa

Science.gov (United States)

Ibrahim, Muazu; Alagidede, Paul

2017-10-01

The role of financial sector development in economic volatility has been extensively studied albeit without informative results largely on the failure of extant studies to decompose volatility into its various components. By disaggregating volatility using the spectral approach, this study examines the effect of financial development on volatility components as well as channels through which finance affects volatility in 23 sub-Saharan African countries over the period 1980-2014. Our findings based on the newly developed panel cointegration estimation strategy reveal that while financial development affects business cycle volatility in a non-linear fashion, its effect on long run fluctuation is imaginary. More specifically, well developed financial sectors dampen volatility. Further findings show that while monetary shocks have large magnifying effect on volatility, their effect in the short run is minuscule. The reverse, however, holds for real shocks. The channels of manifestation shows that financial development dampens (magnifies) the effect of real shocks (monetary shocks) on the components of volatility with the dampening effects consistently larger only in the short run. Strengthening financial sector supervision and cross-border oversight may be very crucial in examining the right levels of finance and price stability necessary to falter economic fluctuations.

Does Exchange Rate Volatility Affect Korea's Seaborne Import Volume?

Directory of Open Access Journals (Sweden)

Chang Beom Kim

2017-03-01

Full Text Available This study used monthly data from 2000 to 2015 to analyze the effects of USD/KRW exchange rate volatility on seaborne import volume in Korea. The results of an autoregressive distributed lag (ARDL analysis indicate that USD/KRW exchange rate volatility has a statistically significant negative influence on Korea's seaborne import volume. Moreover, the results of a vector error correction model (VECM analysis found that the USD/KRW exchange rate volatility exhibited short-term unidirectional causality on import volume and real income, and confirmed bidirectional causality between the real effective exchange rate and exchange rate volatility.

A supply and demand based volatility model for energy prices

International Nuclear Information System (INIS)

Kanamura, Takashi

2009-01-01

This paper proposes a new volatility model for energy prices using the supply-demand relationship, which we call a supply and demand based volatility model. We show that the supply curve shape in the model determines the characteristics of the volatility in energy prices. It is found that the inverse Box-Cox transformation supply curve reflecting energy markets causes the inverse leverage effect, i.e., positive correlation between energy prices and volatility. The model is also used to show that an existing (G)ARCH-M model has the foundations on the supply-demand relationship. Additionally, we conduct the empirical studies analyzing the volatility in the U.S. natural gas prices. (author)

Exchange Rate Volatility and Investment: A Panel Data Cointegration Approach

Directory of Open Access Journals (Sweden)

Ibrahima Amadou DIALLO

2015-05-01

Full Text Available This paper examines the link between real exchange rate volatility and domestic investment by using panel data cointegration techniques. We study the empirical connection between real effective exchange rate volatility and investment for 51 developing countries (23 low-income and 28 middle-income countries. The theoretical relationship between investment and real exchange rate volatility predicts that the effects of exchange rate uncertainty on profits are ambiguous. The empirical results illustrate that real effective exchange rate volatility has a strong negative impact on investment. This outcome is robust in low income and middle income countries, and by using an alternative measurement of exchange rate volatility.

A supply and demand based volatility model for energy prices

Energy Technology Data Exchange (ETDEWEB)

Kanamura, Takashi [J-POWER, 15-1, Ginza 6-Chome, Chuo-ku, Tokyo 104-8165 (Japan)

2009-09-15

This paper proposes a new volatility model for energy prices using the supply-demand relationship, which we call a supply and demand based volatility model. We show that the supply curve shape in the model determines the characteristics of the volatility in energy prices. It is found that the inverse Box-Cox transformation supply curve reflecting energy markets causes the inverse leverage effect, i.e., positive correlation between energy prices and volatility. The model is also used to show that an existing (G)ARCH-M model has the foundations on the supply-demand relationship. Additionally, we conduct the empirical studies analyzing the volatility in the U.S. natural gas prices. (author)

DIRECT OXYGEN ABUNDANCES FOR LOW-LUMINOSITY LVL GALAXIES

Energy Technology Data Exchange (ETDEWEB)

Berg, Danielle A.; Skillman, Evan D. [Institute for Astrophysics, University of Minnesota, 116 Church St. SE, Minneapolis, MN 55455 (United States); Marble, Andrew R.; Engelbracht, Charles W. [Steward Observatory, University of Arizona, 933 N Cherry Ave., Tucson, AZ 85721 (United States); Van Zee, Liese [Astronomy Department, Indiana University, 727 East 3rd Street, Bloomington, IN 47405 (United States); Lee, Janice C. [STScI, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Kennicutt, Robert C. Jr. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom); Calzetti, Daniela [Department of Astronomy, University of Massachusetts, 710 North Pleasant Street, Amherst, MA 01003 (United States); Dale, Daniel A. [Department of Physics and Astronomy, University of Wyoming, 1000 E. University, Laramie, WY 82071 (United States); Johnson, Benjamin D., E-mail: berg@astro.umn.edu, E-mail: skillman@astro.umn.edu, E-mail: cengelbracht@as.arizona.edu, E-mail: amarble@nso.edu, E-mail: vanzee@astro.indiana.edu, E-mail: jlee@stsci.edu, E-mail: calzetti@astro.umass.edu, E-mail: ddale@uwyo.edu, E-mail: johnson@iap.fr [Institut d' Astrophysique de Paris, UMR 7095, 98 bis Bvd Arago, 75014 Paris (France)

2012-08-01

We present MMT spectroscopic observations of H II regions in 42 low luminosity galaxies in the Spitzer Local Volume Legacy survey. For 31 of the 42 galaxies in our sample, we were able to measure the temperature sensitive [O III] {lambda}4363 line at a strength of 4{sigma} or greater, and thus determine oxygen abundances using the 'direct' method. Our results provide the first 'direct' estimates of oxygen abundance for 19 of these galaxies. 'Direct' oxygen abundances were compared to B-band luminosities, 4.5 {mu}m luminosities, and stellar masses in order to characterize the luminosity-metallicity and mass-metallicity relationships at low luminosity. We present and analyze a 'Combined Select' sample composed of 38 objects (drawn from a sub-set of our parent sample and the literature) with 'direct' oxygen abundances and reliable distance determinations (based on the tip of the red giant branch or Cepheid variables). Consistent with previous studies, the B band and 4.5 {mu}m luminosity-metallicity relationships for the 38 objects were found to be 12 + log(O/H) = (6.27 {+-} 0.21) + (- 0.11 {+-} 0.01)M{sub B} and 12 + log(O/H) = (6.10 {+-} 0.21) + (- 0.10 {+-} 0.01)M{sub [4.5]} with dispersions of {sigma} = 0.15 and 0.14, respectively. The slopes of the optical and near-IR L-Z relationships have been reported to be different for galaxies with luminosities greater than that of the LMC. However, the similarity of the slopes of the optical and near-IR L-Z relationships for our sample probably reflects little influence by dust extinction in the low luminosity galaxies. For this sample, we derive a mass-metallicity relationship of 12 + log(O/H) = (5.61 {+-} 0.24) + (0.29 {+-} 0.03)log (M{sub *}), which agrees with previous studies; however, the dispersion ({sigma} = 0.15) is not significantly lower than that of the L-Z relationships. Because of the low dispersions in these relationships, if an accurate distance is available

Modeling returns volatility: Realized GARCH incorporating realized risk measure

Science.gov (United States)

Jiang, Wei; Ruan, Qingsong; Li, Jianfeng; Li, Ye

2018-06-01

This study applies realized GARCH models by introducing several risk measures of intraday returns into the measurement equation, to model the daily volatility of E-mini S&P 500 index futures returns. Besides using the conventional realized measures, realized volatility and realized kernel as our benchmarks, we also use generalized realized risk measures, realized absolute deviation, and two realized tail risk measures, realized value-at-risk and realized expected shortfall. The empirical results show that realized GARCH models using the generalized realized risk measures provide better volatility estimation for the in-sample and substantial improvement in volatility forecasting for the out-of-sample. In particular, the realized expected shortfall performs best for all of the alternative realized measures. Our empirical results reveal that future volatility may be more attributable to present losses (risk measures). The results are robust to different sample estimation windows.

Investor attention and FX market volatility

OpenAIRE

Goddard, John; Kita, Arben; Wang, Qingwei

2015-01-01

We study the relationship between investors’ active attention, measured by a Google search volume index (SVI), and the dynamics of currency prices. Investor attention is correlated with the trading activities of large FX market participants. Investor attention comoves with comtemporaneous FX market volatility and predicts subsequent FX market volatility, after controlling for macroeconomic fundamentals. In addition, investor attention is related to the currency risk premium. Our results sugge...

Decomposing European bond and equity volatility

OpenAIRE

Christiansen, Charlotte

2004-01-01

The paper investigates volatility spillover from US and aggregate European asset markets into European national asset markets. A main contribution is that bond and equity volatilities are analyzed simultaneously. A new model belonging to the "volatilityspillover" family is suggested: The conditional variance of e.g. the unexpected German stock return is divided into separate effects from the contemporaneous idiosyncratic variance of US bonds, US stocks, European bonds, European stocks, German...

Volatile profile of elderberry juice: Effect of lactic acid fermentation using L. plantarum, L. rhamnosus and L. casei strains.

Science.gov (United States)

Ricci, Annalisa; Cirlini, Martina; Levante, Alessia; Dall'Asta, Chiara; Galaverna, Gianni; Lazzi, Camilla

2018-03-01

In this study we explored, for the first time, the lactic acid fermentation of elderberry juice (EJ). A total of 15 strains isolated from dairy and plant matrices, belonging to L. plantarum, L. rhamnosus and L. casei, were used for fermentations. The volatile profile of started and unstarted EJ was characterized by HS-SPME/GC-MS technique after 48h of fermentation and 12days of storage at 4°C. All L. plantarum and L. rhamnosus strains exhibited a good capacity of growth while not all L. casei strains showed the same ability. The aromatic profile of fermented juices was characterized by the presence of 82 volatile compounds pertaining to different classes: alcohols, terpenes and norisoprenoids, organic acids, ketones and esters. Elderberry juice fermented with L. plantarum strains showed an increase of total volatile compounds after 48h while the juices fermented with L. rhamnosus and L. casei exhibited a larger increase after the storage. The highest concentration of total volatile compounds were observed in EJ fermented with L. plantarum 285 isolated from dairy product. Ketones increased in all fermented juices both after fermentation and storage and the most concentrated were acetoin and diacetyl. The organic acids were also affected by lactic acid fermentation and the most abundant acids detected in fermented juices were acetic acid and isovaleric acid. Hexanol, 3-hexen-1-ol (Z) and 2-hexen-1-ol (E) were positively influenced during dairy lactic acid bacteria strains fermentation. The most represented esters were ethyl acetate, methyl isovalerate, isoamyl isovalerate and methyl salicylate, all correlated with fruit notes. Among terpenes and norisoprenoids, β-damascenone resulted the main representative with its typical note of elderberry. Furthermore, coupling obtained data with multivariate statistical analyses, as Principal Component Analysis (PCA) and Classification Trees (CT), it was possible to relate the characteristic volatile profile of samples with

Surface microlayer enrichment of volatile organic compounds and semi-volatile organic compounds in drinking water source.

Science.gov (United States)

Huang, Zhi; Zhou, Wen; Yu, Ya-juan; Zhang, Ai-qian; Han, Shuo-kui; Wang, Lian-sheng

2004-01-01

Enrichment of volatile organic compounds(VOC) and semi-volatility organic compounds(SVOC) in surface microlayer(SM) of three drinking water sources were studied. The enrichment factor(EFs) were 0.67 to 13.37 and 0.16 to 136, respectively. The results showed some VOC and most SVOC could enrich in SM. Some EFs of SVOC was quite high. Suspension and temperature could affect EFs of SVOC, slim wind and water movement do not destroy enrichment of organic in SM.

Beta Risk and Regime Shift in Market Volatility

OpenAIRE

Don U.A. Galagedera; Roland G. Shami

2004-01-01

In this paper, we relate security returns in the thirty securities in the Dow Jones index to regime shifts in the market portfolio (S&P500) volatility. We model market volatility as a multiple-state Markov switching process of order one and estimate non-diversifiable security risk (beta) in the different market volatility regimes. We test the significance of the premium of the beta risk associated with the different market regimes and find evidence of a relationship between security return an...

Volatility Spillovers Across User-Generated Content and Stock Market Performance

NARCIS (Netherlands)