EVALUATING MONITORED NATURAL ATTENUATION FOR RADIONUCLIDE & ORGANIC CONTAMINATION IN GROUNDWATER (SALT LAKE CITY, UT)

EPA Science Inventory

Monitored Natural Attenuation (MNA) for radionuclides and inorganic contaminants is dependent on naturally occurring processes in the subsurface that act without human intervention to reduce the mass, toxicity, mobility, volume or concentration of contaminants. EPA is developing ...

Responses of primate frontal cortex neurons during natural vocal communication.

PubMed

Miller, Cory T; Thomas, A Wren; Nummela, Samuel U; de la Mothe, Lisa A

2015-08-01

The role of primate frontal cortex in vocal communication and its significance in language evolution have a controversial history. While evidence indicates that vocalization processing occurs in ventrolateral prefrontal cortex neurons, vocal-motor activity has been conjectured to be primarily subcortical and suggestive of a distinctly different neural architecture from humans. Direct evidence of neural activity during natural vocal communication is limited, as previous studies were performed in chair-restrained animals. Here we recorded the activity of single neurons across multiple regions of prefrontal and premotor cortex while freely moving marmosets engaged in a natural vocal behavior known as antiphonal calling. Our aim was to test whether neurons in marmoset frontal cortex exhibited responses during vocal-signal processing and/or vocal-motor production in the context of active, natural communication. We observed motor-related changes in single neuron activity during vocal production, but relatively weak sensory responses for vocalization processing during this natural behavior. Vocal-motor responses occurred both prior to and during call production and were typically coupled to the timing of each vocalization pulse. Despite the relatively weak sensory responses a population classifier was able to distinguish between neural activity that occurred during presentations of vocalization stimuli that elicited an antiphonal response and those that did not. These findings are suggestive of the role that nonhuman primate frontal cortex neurons play in natural communication and provide an important foundation for more explicit tests of the functional contributions of these neocortical areas during vocal behaviors. Copyright © 2015 the American Physiological Society.

Responses of primate frontal cortex neurons during natural vocal communication

PubMed Central

Thomas, A. Wren; Nummela, Samuel U.; de la Mothe, Lisa A.

2015-01-01

The role of primate frontal cortex in vocal communication and its significance in language evolution have a controversial history. While evidence indicates that vocalization processing occurs in ventrolateral prefrontal cortex neurons, vocal-motor activity has been conjectured to be primarily subcortical and suggestive of a distinctly different neural architecture from humans. Direct evidence of neural activity during natural vocal communication is limited, as previous studies were performed in chair-restrained animals. Here we recorded the activity of single neurons across multiple regions of prefrontal and premotor cortex while freely moving marmosets engaged in a natural vocal behavior known as antiphonal calling. Our aim was to test whether neurons in marmoset frontal cortex exhibited responses during vocal-signal processing and/or vocal-motor production in the context of active, natural communication. We observed motor-related changes in single neuron activity during vocal production, but relatively weak sensory responses for vocalization processing during this natural behavior. Vocal-motor responses occurred both prior to and during call production and were typically coupled to the timing of each vocalization pulse. Despite the relatively weak sensory responses a population classifier was able to distinguish between neural activity that occurred during presentations of vocalization stimuli that elicited an antiphonal response and those that did not. These findings are suggestive of the role that nonhuman primate frontal cortex neurons play in natural communication and provide an important foundation for more explicit tests of the functional contributions of these neocortical areas during vocal behaviors. PMID:26084912

Fate of naturally occurring Escherichia coli O157:H7 and other zoonotic pathogens during minimally managed bovine feedlot manure composting processes

USDA-ARS?s Scientific Manuscript database

Reducing Escherichia coli O157:H7 in livestock manures before application to cropland is critical for reducing the risk of foodborne illness associated with produce. Our objective was to determine the fate of naturally occurring E. coli O157:H7 and other pathogens during minimally managed on-farm bo...

Anticipated results from dust experiments on cometary missions

NASA Technical Reports Server (NTRS)

Kissel, J.; Fechtig, H.; Grun, E.

1981-01-01

The major scientific objectives of a mission are: to determine the chemical nature and physical structure of comet nuclei, and to characterize the changes that occur as a function of time orbital position; to characterize the chemical and physical nature of the atmospheres and ionospheres of comets as well as the processes that occur in them, and to characterize the development of the atmospheres and ionospheres as functions of time and orbital position; and to determine the nature of comet tails and processes by which they are formed, and to characterize the interaction of comets with the solar wind. Since dust is a major constituent of a comet, the achievement of these goals requires the intensive study of the paticulate emission from a comet.

Wound dressings from naturally-occurring polymers: A review on homopolysaccharide-based composites.

PubMed

Naseri-Nosar, Mahdi; Ziora, Zyta Maria

2018-06-01

Wound dressings are designed to support the wound bed and protect it from the factors that may delay or impede its healing such as contaminations and moisture-loss, thereby facilitating and accelerating the healing process. The materials used to prepare wound dressings include natural and synthetic polymers, as well as their combinations, in the forms of films, sponges and hydrogels. Polysaccharides are naturally-occurring polymers that have been extensively used as wound dressing materials. Homopolysaccharides are a class of polysaccharides consist of only one type of monosaccharide. The current review intends to overview the studies in which wound dressings from naturally-occurring polymers, based on homopolysaccharides, were prepared and evaluated. Homopolysaccharides such as cellulose, chitosan, chitin, pullulan, starch and β-glucan were considered. Copyright © 2018 Elsevier Ltd. All rights reserved.

[Morphogenesis in formative process in vitro from Rehmannia glutinosa].

PubMed

Xue, Jian-ping; Zhang, Ai-min; Liu, Jun; Xu, Xue-feng

2004-01-01

To study the morphogenesis in formative process of tuberous root in vitro from Rehmannia glutinosa and compare the anatomical shape of tuberous root with nature term R. glutinosa. Tuberous roots of different vegetal phase were cut and dyed, then made into paraffin cuts and observed microscope. In anatomical shape, nature R. glutinosa and tuberous root were the same, which showed that no structural variation occurred in tuberous root induced process.

Persistent increases in inflammatory cytokines, Akt, and MAPK/ERK pathways after inhalation exposure of rats to Libby amphibole (LA) or amosite: comparison to effects after intratracheal exposure to LA or naturally occurring asbestos.

EPA Science Inventory

Human exposure to LA and other mined or processed asbestos increases risk of lung inflammation, fibrosis, and cancer. Health risks from exposure to naturally occurring asbestos (NOA) are not as well-understood. Mechanisms of long-term toxicity were compared in male F344 rats expo...

Performance evaluation of functioning of natural-industrial system of mining-processing complex with help of analytical and mathematical models

NASA Astrophysics Data System (ADS)

Bosikov, I. I.; Klyuev, R. V.; Revazov, V. Ch; Pilieva, D. E.

2018-03-01

The article describes research and analysis of hazardous processes occurring in the natural-industrial system and effectiveness assessment of its functioning using mathematical models. Studies of the functioning regularities of the natural and industrial system are becoming increasingly relevant in connection with the formulation of the task of modernizing production and the economy of Russia as a whole. In connection with a significant amount of poorly structured data, it is complicated by regulations for the effective functioning of production processes, social and natural complexes, under which a sustainable development of the natural-industrial system of the mining and processing complex would be ensured. Therefore, the scientific and applied problems, the solution of which allows one to formalize the hidden structural functioning patterns of the natural-industrial system and to make managerial decisions of organizational and technological nature to improve the efficiency of the system, are very relevant.

Natural hazard fatalities in Switzerland from 1946 to 2015

NASA Astrophysics Data System (ADS)

Badoux, Alexandre; Andres, Norina; Techel, Frank; Hegg, Christoph

2016-12-01

A database of fatalities caused by natural hazard processes in Switzerland was compiled for the period between 1946 and 2015. Using information from the Swiss flood and landslide damage database and the Swiss destructive avalanche database, the data set was extended back in time and more hazard processes were added by conducting an in-depth search of newspaper reports. The new database now covers all natural hazards common in Switzerland, categorised into seven process types: flood, landslide, rockfall, lightning, windstorm, avalanche and other processes (e.g. ice avalanches, earthquakes). Included were all fatal accidents associated with natural hazard processes in which victims did not expose themselves to an important danger on purpose. The database contains information on 635 natural hazard events causing 1023 fatalities, which corresponds to a mean of 14.6 victims per year. The most common causes of death were snow avalanches (37 %), followed by lightning (16 %), floods (12 %), windstorms (10 %), rockfall (8 %), landslides (7 %) and other processes (9 %). About 50 % of all victims died in one of the 507 single-fatality events; the other half were killed in the 128 multi-fatality events. The number of natural hazard fatalities that occurred annually during our 70-year study period ranged from 2 to 112 and exhibited a distinct decrease over time. While the number of victims in the first three decades (until 1975) ranged from 191 to 269 per decade, it ranged from 47 to 109 in the four following decades. This overall decrease was mainly driven by a considerable decline in the number of avalanche and lightning fatalities. About 75 % of victims were males in all natural hazard events considered together, and this ratio was roughly maintained in all individual process categories except landslides (lower) and other processes (higher). The ratio of male to female victims was most likely to be balanced when deaths occurred at home (in or near a building), a situation that mainly occurred in association with landslides and avalanches. The average age of victims of natural hazards was 35.9 years and, accordingly, the age groups with the largest number of victims were the 20-29 and 30-39 year-old groups, which in combination represented 34 % of all fatalities. It appears that the overall natural hazard mortality rate in Switzerland over the past 70 years has been relatively low in comparison to rates in other countries or rates of other types of fatal accidents in Switzerland. However, a large variability in mortality rates was observed within the country with considerably higher rates in Alpine environments.

Are Nonadjacent Collocations Processed Faster?

ERIC Educational Resources Information Center

Vilkaite, Laura

2016-01-01

Numerous studies have shown processing advantages for collocations, but they only investigated processing of adjacent collocations (e.g., "provide information"). However, in naturally occurring language, nonadjacent collocations ("provide" some of the "information") are equally, if not more frequent. This raises the…

Naturally Occurring Radioactive Materials (NORM)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gray, P.

1997-02-01

This paper discusses the broad problems presented by Naturally Occuring Radioactive Materials (NORM). Technologically Enhanced naturally occuring radioactive material includes any radionuclides whose physical, chemical, radiological properties or radionuclide concentration have been altered from their natural state. With regard to NORM in particular, radioactive contamination is radioactive material in an undesired location. This is a concern in a range of industries: petroleum; uranium mining; phosphorus and phosphates; fertilizers; fossil fuels; forestry products; water treatment; metal mining and processing; geothermal energy. The author discusses in more detail the problem in the petroleum industry, including the isotopes of concern, the hazards theymore » present, the contamination which they cause, ways to dispose of contaminated materials, and regulatory issues. He points out there are three key programs to reduce legal exposure and problems due to these contaminants: waste minimization; NORM assesment (surveys); NORM compliance (training).« less

Reproducing stone monument photosynthetic-based colonization under laboratory conditions.

PubMed

Miller, Ana Zélia; Laiz, Leonila; Gonzalez, Juan Miguel; Dionísio, Amélia; Macedo, Maria Filomena; Saiz-Jimenez, Cesareo

2008-11-01

In order to understand the biodeterioration process occurring on stone monuments, we analyzed the microbial communities involved in these processes and studied their ability to colonize stones under controlled laboratory experiments. In this study, a natural green biofilm from a limestone monument was cultivated, inoculated on stone probes of the same lithotype and incubated in a laboratory chamber. This incubation system, which exposes stone samples to intermittently sprinkling water, allowed the development of photosynthetic biofilms similar to those occurring on stone monuments. Denaturing gradient gel electrophoresis (DGGE) analysis was used to evaluate the major microbial components of the laboratory biofilms. Cyanobacteria, green microalgae, bacteria and fungi were identified by DNA-based molecular analysis targeting the 16S and 18S ribosomal RNA genes. The natural green biofilm was mainly composed by the Chlorophyta Chlorella, Stichococcus, and Trebouxia, and by Cyanobacteria belonging to the genera Leptolyngbya and Pleurocapsa. A number of bacteria belonging to Alphaproteobacteria, Bacteroidetes and Verrucomicrobia were identified, as well as fungi from the Ascomycota. The laboratory colonization experiment on stone probes showed a colonization pattern similar to that occurring on stone monuments. The methodology described in this paper allowed to reproduce a colonization equivalent to the natural biodeteriorating process.

HBV subgenotypes F1b and F4 replication induces an incomplete autophagic process in hepatocytes: Role of BCP and preCore mutations.

PubMed

Elizalde, María Mercedes; Pérez, Paula Soledad; Sevic, Ina; Grasso, Daniel; Ropolo, Alejandro; Barbini, Luciana; Campos, Rodolfo Héctor; Vaccaro, María Inés; Flichman, Diego Martín

2018-01-01

Hepatitis B virus (HBV) genotypes and mutants have been associated with differences in clinical and virological characteristics. Autophagy is a cellular process that degrades long-lived proteins and damaged organelles. Viruses have evolved mechanisms to alter this process to survive in host cells. In this work, we studied the modulation of autophagy by the replication of HBV subgenotypes F1b and F4, and the naturally occurring mutants BCP and preCore. HBV subgenotypes F1b and F4 replication induced accumulation of autophagosomes in hepatoma cells. However, no autophagic protein degradation was observed, indicating a blockage of autophagic flux at later stages. This inhibition of autophagy flux might be due to an impairment of lysosomal acidification in hepatoma cells. Moreover, HBV-mediated autophagy modulation was independent of the viral subgenotypes and enhanced in viruses with BCP and preCore naturally occurring mutations. These results contribute to understand the mechanisms by which different HBV variants contribute to the pathogenesis of HBV infections. In addition, this study is the first to describe the role that two highly prevalent naturally occurring mutations exert on the modulation of HBV-induced autophagy.

HBV subgenotypes F1b and F4 replication induces an incomplete autophagic process in hepatocytes: Role of BCP and preCore mutations

PubMed Central

Pérez, Paula Soledad; Sevic, Ina; Ropolo, Alejandro; Barbini, Luciana; Campos, Rodolfo Héctor; Vaccaro, María Inés; Flichman, Diego Martín

2018-01-01

Hepatitis B virus (HBV) genotypes and mutants have been associated with differences in clinical and virological characteristics. Autophagy is a cellular process that degrades long-lived proteins and damaged organelles. Viruses have evolved mechanisms to alter this process to survive in host cells. In this work, we studied the modulation of autophagy by the replication of HBV subgenotypes F1b and F4, and the naturally occurring mutants BCP and preCore. HBV subgenotypes F1b and F4 replication induced accumulation of autophagosomes in hepatoma cells. However, no autophagic protein degradation was observed, indicating a blockage of autophagic flux at later stages. This inhibition of autophagy flux might be due to an impairment of lysosomal acidification in hepatoma cells. Moreover, HBV-mediated autophagy modulation was independent of the viral subgenotypes and enhanced in viruses with BCP and preCore naturally occurring mutations. These results contribute to understand the mechanisms by which different HBV variants contribute to the pathogenesis of HBV infections. In addition, this study is the first to describe the role that two highly prevalent naturally occurring mutations exert on the modulation of HBV-induced autophagy. PMID:29738548

Screening of Natural Antimicrobials for Inhibition of E. coli O157:H7 in a Solidified Apple Juice Medium

USDA-ARS?s Scientific Manuscript database

Introduction: Naturally occurring antimicrobials such as plant extracts and essential oils have been used in the food industry for years. Due to increased consumer demand for minimally processed juices there has been increased interest in the use of novel antimicrobial compounds isolated from natur...

A novel LCD (coal tar) solution for psoriasis does not discolor naturally light or color-processed hair in an exaggerated exposure test model.

PubMed

Johnson, Colleen; Edison, Brenda; Brouda, Irina; Green, Barbara

2009-09-01

Scalp psoriasis is reported to occur in 50-80% of psoriasis sufferers. Treatment of scalp psoriasis requires special consideration of product esthetics and staining potential due to the presence of hair. To evaluate the potential of a new, marketed liquor carbonis distillate (LCD; coal tar) solution to discolor naturally light or color-processed hair under exaggerated exposure conditions. Samples of naturally light and color-processed hair from a single donor were exposed to LCD solution repeatedly over 14 days and via submergence for 24 h. Color of LCD-treated hair samples was compared with untreated control hair samples. LCD solution did not discolor naturally light or color-processed hair following repeated exposures and 24 h submergence. The marketed LCD solution does not appear to discolor naturally light or color-processed hair.

Modeling of the initiation and evolution of a laser-ionized column in the lower atmosphere - 314.5 nm wavelength resonant multiphoton ionization of naturally occurring argon

NASA Technical Reports Server (NTRS)

Fetzer, G. J.; Stockley, J. E.

1992-01-01

A 3+1 resonant multiphoton ionization process in naturally occurring argon is studied at 314.5 nm as a candidate for providing a long ionized channel through the atmosphere. Results are presented which indicate peak electron densities up to 10 exp 8/cu cm can be created using laser intensities on the order of 10 exp 8 W/sq cm.

Novel natural food antimicrobials.

PubMed

Juneja, Vijay K; Dwivedi, Hari P; Yan, Xianghe

2012-01-01

Naturally occurring antimicrobial compounds could be applied as food preservatives to protect food quality and extend the shelf life of foods and beverages. These compounds are naturally produced and isolated from various sources, including plants, animals and microorganisms, in which they constitute part of host defense systems. Many naturally occurring compounds, such as nisin, plant essential oils, and natamycin, have been widely studied and are reported to be effective in their potential role as antimicrobial agents against spoilage and pathogenic microorganisms. Although some of these natural antimicrobials are commercially available and applied in food processing, their efficacy, consumer acceptance and regulation are not well defined. This manuscript reviews natural antimicrobial compounds with reference to their applications in food when applied individually or in combination with other hurdles. It also reviews the mechanism of action of selected natural antimicrobials, factors affecting their antimicrobial activities, and future prospects for use of natural antimicrobials in the food industry.

Natural radionuclide concentrations in processed materials from Thai mineral industries.

PubMed

Chanyotha, S; Kranrod, C; Chankow, N; Kritsananuwat, R; Sriploy, P; Pangza, K

2012-11-01

The naturally occurring radioactive materials (NORMs) distributed in products, by-products and waste produced from Thai mineral industries were investigated. Samples were analysed for radioactivity concentrations of two principal NORM isotopes: (226)Ra and (228)Ra. The enrichment of NORM was found to occur during the treatment process of some minerals. The highest activity of (226)Ra (7 × 10(7) Bq kg(-1)) was in the scale from tantalum processing. The radium concentration in the discarded by-product material from metal ore dressing was also enriched by 3-10 times. Phosphogypsum, a waste produced from the production of phosphate fertilisers, contained 700 times the level of (226)Ra concentration found in phosphate ore. Hence, these residues were also sources of exposure to workers and the public, which needed to be controlled.

Evaluating differences in forest fragmentation and restoration between western natural forests and southeastern plantation forests in the United States.

PubMed

Ren, Xinyu; Lv, Yingying; Li, Mingshi

2017-03-01

Changes in forest ecosystem structure and functions are considered some of the research issues in landscape ecology. In this study, advancing Forman's theory, we considered five spatially explicit processes associated with fragmentation, including perforation, dissection, subdivision, shrinkage, and attrition, and two processes associated with restoration, i.e., increment and expansion processes. Following this theory, a forest fragmentation and restoration process model that can detect the spatially explicit processes and ecological consequences of forest landscape change was developed and tested in the current analysis. Using the National Land Cover Databases (2001, 2006 and 2011), the forest fragmentation and restoration process model was applied to US western natural forests and southeastern plantation forests to quantify and classify forest patch losses into one of the four fragmentation processes (the dissection process was merged into the subdivision process) and to classify the newly gained forest patches based on the two restoration processes. At the same time, the spatio-temporal differences in fragmentation and restoration patterns and trends between natural forests and plantations were further compared. Then, through overlaying the forest fragmentation/restoration processes maps with targeting year land cover data and land ownership vectors, the results from forest fragmentation and the contributors to forest restoration in federal and nonfederal lands were identified. Results showed that, in natural forests, the forest change patches concentrated around the urban/forest, cultivated/forest, and shrubland/forest interfaces, while the patterns of plantation change patches were scattered sparsely and irregularly. The shrinkage process was the most common type in forest fragmentation, and the average size was the smallest. Expansion, the most common restoration process, was observed in both natural forests and plantations and often occurred around the previous expansion or covered the previous subdivision or shrinkage processes. The overall temporal fragmentation pattern of natural forests had a "perforation-subdivision/shrinkage-attrition" pathway, which corresponded to Forman's landscape fragmentation rule, while the plantation forests did not follow the rule strictly. The main land cover types resulted from forest fragmentation in natural forests and plantation forests were shrubland and herbaceous, mainly through subdivision and shrinkages process. The processes and effects of restoration of plantation forests were more diverse and efficient, compared to the natural forest, which were simpler with a lower regrowth rate. The fragmentation mostly occurred in nonfederal lands. In natural forests, forest fragmentation pattern differed in different land tenures, yet plantations remained the same in federal and nonfederal lands. Copyright © 2016 Elsevier Ltd. All rights reserved.

Statistics of the Vestibular Input Experienced during Natural Self-Motion: Implications for Neural Processing

PubMed Central

Carriot, Jérome; Jamali, Mohsen; Chacron, Maurice J.

2014-01-01

It is widely believed that sensory systems are optimized for processing stimuli occurring in the natural environment. However, it remains unknown whether this principle applies to the vestibular system, which contributes to essential brain functions ranging from the most automatic reflexes to spatial perception and motor coordination. Here we quantified, for the first time, the statistics of natural vestibular inputs experienced by freely moving human subjects during typical everyday activities. Although previous studies have found that the power spectra of natural signals across sensory modalities decay as a power law (i.e., as 1/fα), we found that this did not apply to natural vestibular stimuli. Instead, power decreased slowly at lower and more rapidly at higher frequencies for all motion dimensions. We further establish that this unique stimulus structure is the result of active motion as well as passive biomechanical filtering occurring before any neural processing. Notably, the transition frequency (i.e., frequency at which power starts to decrease rapidly) was lower when subjects passively experienced sensory stimulation than when they actively controlled stimulation through their own movement. In contrast to signals measured at the head, the spectral content of externally generated (i.e., passive) environmental motion did follow a power law. Specifically, transformations caused by both motor control and biomechanics shape the statistics of natural vestibular stimuli before neural processing. We suggest that the unique structure of natural vestibular stimuli will have important consequences on the neural coding strategies used by this essential sensory system to represent self-motion in everyday life. PMID:24920638

Investigation of the environmental impacts of naturally occurring radionuclides in the processing of sulfide ores for gold using gamma spectrometry.

PubMed

Gbadago, J K; Faanhof, A; Darko, E O; Schandorf, C

2011-09-01

The possible environmental impacts of naturally occurring radionuclides on workers and a critical community, as a result of milling and processing sulfide ores for gold by a mining company at Bogoso in the western region of Ghana, have been investigated using gamma spectroscopy. Indicative doses for the workers during sulfide ore processing were calculated from the activity concentrations measured at both physical and chemical processing stages. The dose rate, annual effective dose equivalent, radium equivalent activity, external and internal hazard indices, and radioactivity level index for tailings, for the de-silted sediments of run-off from the vicinity of the tailings dam through the critical community, and for the soils of the critical community's basic schools were calculated and found to be lower than their respective permissible limits. The environmental impact of the radionuclides is therefore expected to be low in this mining environment.

Naturally occurring radioactive material (NORM) from a former phosphoric acid processing plant.

PubMed

Beddow, H; Black, S; Read, D

2006-01-01

In recent years there has been an increasing awareness of the radiological impact of non-nuclear industries that extract and/or process ores and minerals containing naturally occurring radioactive material (NORM). These industrial activities may result in significant radioactive contamination of (by-) products, wastes and plant installations. In this study, scale samples were collected from a decommissioned phosphoric acid processing plant. To determine the nature and concentration of NORM retained in pipe-work and associated process plant, four main areas of the site were investigated: (1) the 'Green Acid Plant', where crude acid was concentrated; (2) the green acid storage tanks; (3) the Purified White Acid (PWA) plant, where inorganic impurities were removed; and (4) the solid waste, disposed of on-site as landfill. The scale samples predominantly comprise the following: fluorides (e.g. ralstonite); calcium sulphate (e.g. gypsum); and an assemblage of mixed fluorides and phosphates (e.g. iron fluoride hydrate, calcium phosphate), respectively. The radioactive inventory is dominated by 238U and its decay chain products, and significant fractionation along the series occurs. Compared to the feedstock ore, elevated concentrations (< or =8.8 Bq/g) of 238U were found to be retained in installations where the process stream was rich in fluorides and phosphates. In addition, enriched levels (< or =11 Bq/g) of 226Ra were found in association with precipitates of calcium sulphate. Water extraction tests indicate that many of the scales and waste contain significantly soluble materials and readily release radioactivity into solution.

ENVIRONMENTAL QUALITY AND LANDSCAPE-RISK ASSESSMENT IN THE YANTRA RIVER BASIN

EPA Science Inventory

Landscape characteristics exert their impact on the processes occurring in river basins in many directions and may influence in a different way the environmental security and some related constraints like extreme natural events. The complex nature of landscape structure and dynam...

Regulation of naturally occurring radioactive materials in Australia.

PubMed

Jeffries, Cameron; Akber, Riaz; Johnston, Andrew; Cassels, Brad

2011-07-01

In order to promote uniformity between jurisdictions, the Australian Radiation Protection and Nuclear Safety Agency (ARPANSA) has developed the National Directory for Radiation Protection, which is a regulatory framework that all Australian governments have agreed to adopt. There is a large and diverse range of industries involved in mining or mineral processing, and the production of fossil fuels in Australia. Enhanced levels of naturally occurring radionuclides can be associated with mineral extraction and processing, other industries (e.g. metal recycling) and some products (e.g. plasterboard). ARPANSA, in conjunction with industry and State regulators, has undertaken a review and assessment of naturally occurring radioactive material (NORM) management in Australian industries. This review has resulted in guidance on the management of NORM that will be included in the National Directory for Radiation Protection. The first NORM safety guide provides the framework for NORM management and addresses specific NORM issues in oil and gas production, bauxite, aluminium and phosphate industries. Over time further guidance material for other NORM-related industries will be developed. This presentation will provide an overview of the regulatory approach to managing NORM industries in Australia.

The banana code-natural blend processing in the olfactory circuitry of Drosophila melanogaster.

PubMed

Schubert, Marco; Hansson, Bill S; Sachse, Silke

2014-01-01

Odor information is predominantly perceived as complex odor blends. For Drosophila melanogaster one of the most attractive blends is emitted by an over-ripe banana. To analyze how the fly's olfactory system processes natural blends we combined the experimental advantages of gas chromatography and functional imaging (GC-I). In this way, natural banana compounds were presented successively to the fly antenna in close to natural occurring concentrations. This technique allowed us to identify the active odor components, use these compounds as stimuli and measure odor-induced Ca(2+) signals in input and output neurons of the Drosophila antennal lobe (AL), the first olfactory neuropil. We demonstrate that mixture interactions of a natural blend are very rare and occur only at the AL output level resulting in a surprisingly linear blend representation. However, the information regarding single components is strongly modulated by the olfactory circuitry within the AL leading to a higher similarity between the representation of individual components and the banana blend. This observed modulation might tune the olfactory system in a way to distinctively categorize odor components and improve the detection of suitable food sources. Functional GC-I thus enables analysis of virtually any unknown natural odorant blend and its components in their relative occurring concentrations and allows characterization of neuronal responses of complete neural assemblies. This technique can be seen as a valuable complementary method to classical GC/electrophysiology techniques, and will be a highly useful tool in future investigations of insect-insect and insect-plant chemical interactions.

Determination of Cr(III) solids formed by reduction of Cr(VI) in a contaminated fractured bedrock aquifer: evidence for natural attenuation of Cr(VI)

EPA Science Inventory

Hexavalent chromium Cr(VI) is toxic and can be highly mobile in many aquifer systems. Redox reactions with naturally occurring minerals and organic compounds can reduce Cr(VI) to Cr(III), forming labile Cr(III) oxyhydroxide precipitates, which is a natural attenuation process. In...

Finding the traces of behavioral and cognitive processes in big data and naturally occurring datasets.

PubMed

Paxton, Alexandra; Griffiths, Thomas L

2017-10-01

Today, people generate and store more data than ever before as they interact with both real and virtual environments. These digital traces of behavior and cognition offer cognitive scientists and psychologists an unprecedented opportunity to test theories outside the laboratory. Despite general excitement about big data and naturally occurring datasets among researchers, three "gaps" stand in the way of their wider adoption in theory-driven research: the imagination gap, the skills gap, and the culture gap. We outline an approach to bridging these three gaps while respecting our responsibilities to the public as participants in and consumers of the resulting research. To that end, we introduce Data on the Mind ( http://www.dataonthemind.org ), a community-focused initiative aimed at meeting the unprecedented challenges and opportunities of theory-driven research with big data and naturally occurring datasets. We argue that big data and naturally occurring datasets are most powerfully used to supplement-not supplant-traditional experimental paradigms in order to understand human behavior and cognition, and we highlight emerging ethical issues related to the collection, sharing, and use of these powerful datasets.

Natural polymer biocomposites produced from processing raw wood flour by severe shear deformation.

PubMed

Zhang, Xiaoqing; Wu, Xiaolin; Haryono, Hengky; Xia, Kenong

2014-11-26

Wood flour (WF) based natural polymer biocomposites were produced using the equal channel angular pressing (ECAP) technique. The wood particle structures were disrupted and the cellulose crystallinity was decreased while bulk materials were formed with continuous phase structures by the severe shear-deformation during ECAP. The mechanical properties of the processed WF materials were enhanced when the processing temperature was increased due to enhanced intermolecular interactions and thermal crosslinking reactions among WF components. The processing capability was improved by using wheat gluten (WG) as additives, leading to significantly reduced processing temperature. Effective chain penetration and strong intermolecular interactions in conjunction with chemical crosslinking occurred between WG and the amorphous components in WF. However, the thermal decomposition of the WG component also occurred at increased temperatures, resulting in a decrease in the mechanical strength of the WF/WG composites. The result has demonstrated that ECAP is a promising methodology to produce renewable and degradable biocomposites from wood waste. Copyright © 2014 Elsevier Ltd. All rights reserved.

Bark beetle responses to vegetation management practices

Treesearch

Joel D. McMillin; Christopher J. Fettig

2009-01-01

Native tree-killing bark beetles (Coleoptera: Curculionidae, Scolytinae) are a natural component of forest ecosystems. Eradication is neither possible nor desirable and periodic outbreaks will occur as long as susceptible forests and favorable climatic conditions co-exist. Recent changes in forest structure and tree composition by natural processes and management...

PERCHLORATE LEVELS IN SAMPLES OF SODIUM NITRATE FERTILIZER DERIVED FROM CHILEAN CALICHE

EPA Science Inventory

Paleogeochemical deposits in northern Chile are a rich source of naturally occurring sodium nitrate. These caliche ores are mined and processed to isolate NaNO3 (16-0-0) for use in fertilizers. Coincidentally, these very same deposits are a natural soure of perchlorate anion (C...

Review of research on impacts to biota of discharges of naturally occurring radionuclides in produced water to the marine environment.

PubMed

Hosseini, Ali; Brown, Justin E; Gwynn, Justin P; Dowdall, Mark

2012-11-01

Produced water has been described as the largest volume waste stream in the exploration and production process of oil and gas. It is accompanied by discharges of naturally occurring radionuclides raising concerns over the potential radiological impacts of produced water on marine biota. In the Northern European marine environment, radioactivity in produced water has received substantial attention owing to the OSPAR Radioactive Substances Strategy which aims at achieving 'concentrations in the environment near background values for naturally occurring radioactive substances'. This review provides an overview of published research on the impacts to biota from naturally occurring radionuclides discharged in produced water by the offshore oil and gas industry. In addition to summarising studies and data that deal directly with the issue of dose and effect, the review also considers studies related to the impact of added chemicals on the fate of discharged radionuclides. The review clearly illustrates that only a limited number of studies have investigated possible impacts on biota from naturally occurring radionuclides present in produced water. Hence, although these studies indicate that the risk to the environment from naturally occurring radionuclides discharged in produced water is negligible, the substantial uncertainties involved in the assessments of impact make it difficult to be conclusive. With regard to the complexity involved in the problem under consideration there is a pressing need to supplement existing data and acquire new knowledge. Finally, the present work identifies some knowledge gaps to indicate future research requirements. Copyright © 2012 Elsevier B.V. All rights reserved.

Statistics of the vestibular input experienced during natural self-motion: implications for neural processing.

PubMed

Carriot, Jérome; Jamali, Mohsen; Chacron, Maurice J; Cullen, Kathleen E

2014-06-11

It is widely believed that sensory systems are optimized for processing stimuli occurring in the natural environment. However, it remains unknown whether this principle applies to the vestibular system, which contributes to essential brain functions ranging from the most automatic reflexes to spatial perception and motor coordination. Here we quantified, for the first time, the statistics of natural vestibular inputs experienced by freely moving human subjects during typical everyday activities. Although previous studies have found that the power spectra of natural signals across sensory modalities decay as a power law (i.e., as 1/f(α)), we found that this did not apply to natural vestibular stimuli. Instead, power decreased slowly at lower and more rapidly at higher frequencies for all motion dimensions. We further establish that this unique stimulus structure is the result of active motion as well as passive biomechanical filtering occurring before any neural processing. Notably, the transition frequency (i.e., frequency at which power starts to decrease rapidly) was lower when subjects passively experienced sensory stimulation than when they actively controlled stimulation through their own movement. In contrast to signals measured at the head, the spectral content of externally generated (i.e., passive) environmental motion did follow a power law. Specifically, transformations caused by both motor control and biomechanics shape the statistics of natural vestibular stimuli before neural processing. We suggest that the unique structure of natural vestibular stimuli will have important consequences on the neural coding strategies used by this essential sensory system to represent self-motion in everyday life. Copyright © 2014 the authors 0270-6474/14/348347-11$15.00/0.

Evaluated nuclear data files for the naturally-occurring isotopes of cadmium

DOE Office of Scientific and Technical Information (OSTI.GOV)

McCabe, J.; Smith, A.B.; Meadows, J.W.

1993-06-01

Comprehensive neutronic evaluated data files for the naturally-occurring isotopes of cadmium are deduced from experimental data and nuclear models, and presented in the ENDF/B-VI formats. Particular attention is given to those processes relevant to fuel-cycle and fission-product applications. Comparisons are made with prior evaluations of the cadmium isotopes, and discrepancies and consistencies cited. Some of the discrepancies are very large 9.9 as much as 100%), and the differences have the potential for a pronounced impact on applications usage. The present files are comprehensive, including may important processes that are not represented in the contemporary ENDF/B-VI system. Recommendations are made formore » future measurements where appropriate.« less

Postfact phenomena of the wet-steam flow electrization in turbines

NASA Astrophysics Data System (ADS)

Tarelin, A. A.

2017-11-01

Physical processes occurring in a turbine with natural electrization of a humidity-steam flow and their effect on efficiency and reliability of the turbine operation has been considered. Causes of the electrical potential occurrence on a rotor shaft are analyzed. The wet steam's electrization exposure on the electrical potential that is one of the major factors of bearings' electroerosion has been demonstrated on the full-scale installation. Hydrogen formation in wheelspace of the turbine as a result of electrochemical processes and electric field exposure of the space charge has been considered. Hydrogen concentration dependence on a volume charge density in the steam flow has been determined. It is stated that the processes occurring behind the final stage of wet-steam turbines are similar to the ones in elaerosol ectrostatic generators. It has been demonstrated that this phenomenon causes the flow's temporal inhibition and starts pulsations. These factors' impact on power loss of the turbine has been evaluated and recommendations for their elimination have been offered. It has been determined that motions of charged drops can cause self-maintained discharges inside of the flow and between the flow and grounded surfaces that are accompanied by electromagnetic radiation of the wide spectrum. The integrated studies have shown that physical phenomena occurring due to natural electrization negatively affect efficiency and reliability of the turbine operation. Practical recommendations allowing one to minimize the negative effects of the flow natural electrization process have been offered.

Predictability and extended-range prognosis in natural hazard risk mitigation process: A case study over west Greece

NASA Astrophysics Data System (ADS)

Matsangouras, Ioannis T.; Nastos, Panagiotis T.

2014-05-01

Natural hazards pose an increasing threat to society and new innovative techniques or methodologies are necessary to be developed, in order to enhance the risk mitigation process in nowadays. It is commonly accepted that disaster risk reduction is a vital key for future successful economic and social development. The systematic improvement accuracy of extended-range prognosis products, relating with monthly and seasonal predictability, introduced them as a new essential link in risk mitigation procedure. Aiming at decreasing the risk, this paper presents the use of seasonal and monthly forecasting process that was tested over west Greece from September to December, 2013. During that season significant severe weather events occurred, causing significant impact to the local society (severe storms/rainfalls, hail, flash floods, etc). Seasonal and monthly forecasting products from European Centre for Medium-Range Weather Forecasts (ECMWF) depicted, with probabilities stratified by terciles, areas of Greece where significant weather may occur. As atmospheric natural hazard early warning systems are able to deliver warnings up to 72 hours in advance, this study illustrates that extended-range prognosis could be introduced as a new technique in risk mitigation. Seasonal and monthly forecast products could highlight extended areas where severe weather events may occur in one month lead time. In addition, a risk mitigation procedure, that extended prognosis products are adopted, is also presented providing useful time to preparedness process at regional administration level.

Threat as a feature in visual semantic object memory.

PubMed

Calley, Clifford S; Motes, Michael A; Chiang, H-Sheng; Buhl, Virginia; Spence, Jeffrey S; Abdi, Hervé; Anand, Raksha; Maguire, Mandy; Estevez, Leonardo; Briggs, Richard; Freeman, Thomas; Kraut, Michael A; Hart, John

2013-08-01

Threatening stimuli have been found to modulate visual processes related to perception and attention. The present functional magnetic resonance imaging (fMRI) study investigated whether threat modulates visual object recognition of man-made and naturally occurring categories of stimuli. Compared with nonthreatening pictures, threatening pictures of real items elicited larger fMRI BOLD signal changes in medial visual cortices extending inferiorly into the temporo-occipital (TO) "what" pathways. This region elicited greater signal changes for threatening items compared to nonthreatening from both the natural-occurring and man-made stimulus supraordinate categories, demonstrating a featural component to these visual processing areas. Two additional loci of signal changes within more lateral inferior TO areas (bilateral BA18 and 19 as well as the right ventral temporal lobe) were detected for a category-feature interaction, with stronger responses to man-made (category) threatening (feature) stimuli than to natural threats. The findings are discussed in terms of visual recognition of processing efficiently or rapidly groups of items that confer an advantage for survival. Copyright © 2012 Wiley Periodicals, Inc.

Divergent selection for amino-nitrogen concentration in sugarbeet roots

USDA-ARS?s Scientific Manuscript database

Improvements in sugarbeet (Beta vulgaris L.) processing quality, and therefore the cost-effectiveness of processing, will enhance beet sugar’s competitiveness with cane sugar and alternative sweeteners. Amino-nitrogen is one of the naturally occurring constituents of sugarbeet, referred to as impuri...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Andrews, V.E.

Naturally occurring radioactivity was measured in the atmospheric emissions and process materials of a thermal phosphate (elemental phosphorus) plant. Representative exhaust stack samples were collected from each process in the plant. The phosphate ore contained 12 to 20 parts per million uranium. Processes, emission points, and emission controls are described. Radioactivity concentrations and emission rates from the sources sampled are given.

Incidence, species and antimicrobial resistance of naturally occurring Campylobacter isolates from quail carcasses sampled in a commercial processing facility

USDA-ARS?s Scientific Manuscript database

Most of the published information about the presence of Campylobacter on processed poultry is from studies with chickens and turkeys; therefore there is a paucity of published material about the presence of Campylobacter on commercially processed quail (Coturnix coturnix). The objective of this stud...

Classrooms as Complex Adaptive Systems: A Relational Model

ERIC Educational Resources Information Center

Burns, Anne; Knox, John S.

2011-01-01

In this article, we describe and model the language classroom as a complex adaptive system (see Logan & Schumann, 2005). We argue that linear, categorical descriptions of classroom processes and interactions do not sufficiently explain the complex nature of classrooms, and cannot account for how classroom change occurs (or does not occur), over…

Interaction of flavonoids, the naturally occurring antioxidants with different media: A UV-visible spectroscopic study

NASA Astrophysics Data System (ADS)

Naseem, Bushra; Shah, S. W. H.; Hasan, Aurangzeb; Sakhawat Shah, S.

2010-04-01

Quantitative parameters for interaction of flavonoids—the naturally occurring antioxidants, with solvents and surfactants are determined using UV-visible absorption spectroscopy. The availability of flavonoids; kaempferol, apigenin, kaempferide and rhamnetin in micelles of sodium dodecyl sulfate (SDS) is reflected in terms of partition coefficient, Kc. Thermodynamic calculations show that the process of transfer of flavonoid molecules to anionic micelles of SDS is energy efficient. A distortion in flavonoid's morphology occurs in case of kaempferol and apigenin in surfactant and water, exhibited in terms of a new band in the UV region of electronic spectra of these flavonoids. The partition coefficients of structurally related flavonoids are correlated with their antioxidant activities.

Protein abundances can distinguish between naturally-occurring and laboratory strains of Yersinia pestis, the causative agent of plague

DOE PAGES

Merkley, Eric D.; Sego, Landon H.; Lin, Andy; ...

2017-08-30

Adaptive processes in bacterial species can occur rapidly in laboratory culture, leading to genetic divergence between naturally occurring and laboratory-adapted strains. Differentiating wild and closely-related laboratory strains is clearly important for biodefense and bioforensics; however, DNA sequence data alone has thus far not provided a clear signature, perhaps due to lack of understanding of how diverse genome changes lead to adapted phenotypes. Protein abundance profiles from mass spectrometry-based proteomics analyses are a molecular measure of phenotype. Proteomics data contains sufficient information that powerful statistical methods can uncover signatures that distinguish wild strains of Yersinia pestis from laboratory-adapted strains.

Microfluidic colloid filtration

PubMed Central

Linkhorst, John; Beckmann, Torsten; Go, Dennis; Kuehne, Alexander J. C.; Wessling, Matthias

2016-01-01

Filtration of natural and colloidal matter is an essential process in today’s water treatment processes. The colloidal matter is retained with the help of micro- and nanoporous synthetic membranes. Colloids are retained in a “cake layer” – often coined fouling layer. Membrane fouling is the most substantial problem in membrane filtration: colloidal and natural matter build-up leads to an increasing resistance and thus decreasing water transport rate through the membrane. Theoretical models exist to describe macroscopically the hydrodynamic resistance of such transport and rejection phenomena; however, visualization of the various phenomena occurring during colloid retention is extremely demanding. Here we present a microfluidics based methodology to follow filter cake build up as well as transport phenomena occuring inside of the fouling layer. The microfluidic colloidal filtration methodology enables the study of complex colloidal jamming, crystallization and melting processes as well as translocation at the single particle level. PMID:26927706

Redox Conditions in Selected Principal Aquifers of the United States

USGS Publications Warehouse

McMahon, P.B.; Cowdery, T.K.; Chapelle, F.H.; Jurgens, B.C.

2009-01-01

Reduction/oxidation (redox) processes affect the quality of groundwater in all aquifer systems. Redox processes can alternately mobilize or immobilize potentially toxic metals associated with naturally occurring aquifer materials, contribute to the degradation or preservation of anthropogenic contami-nants, and generate undesirable byproducts, such as dissolved manganese (Mn2+), ferrous iron (Fe2+), hydrogen sulfide (H2S), and methane (CH4). Determining the kinds of redox processes that occur in an aquifer system, documenting their spatial distribution, and understanding how they affect concentrations of natural or anthropogenic contaminants are central to assessing and predicting the chemical quality of groundwater. This Fact Sheet extends the analysis of U.S. Geological Survey authors to additional principal aquifer systems by applying a framework developed by the USGS to a larger set of water-quality data from the USGS national water databases. For a detailed explanation, see the 'Introduction' in the Fact Sheet.

Comparison of the basin-scale effect of dredging operations and natural estuarine processes on suspended sediment concentration

USGS Publications Warehouse

Schoellhamer, D.H.

2002-01-01

Suspended sediment concentration (SSC) data from San Pablo Bay, California, were analyzed to compare the basin-scale effect of dredging and disposal of dredged material (dredging operations) and natural estuarine processes. The analysis used twelve 3-wk to 5-wk periods of mid-depth and near-bottom SSC data collected at Point San Pablo every 15 min from 1993-1998. Point San Pablo is within a tidal excursion of a dredged-material disposal site. The SSC data were compared to dredging volume, Julian day, and hydrodynamic and meteorological variables that could affect SSC. Kendall's ??, Spearman's ??, and weighted (by the fraction of valid data in each period) Spearman's ??w correlation coefficients of the variables indicated which variables were significantly correlated with SSC. Wind-wave resuspension had the greatest effect on SSC. Median water-surface elevation was the primary factor affecting mid-depth SSC. Greater depths inhibit wind-wave resuspension of bottom sediment and indicate greater influence of less turbid water from down estuary. Seasonal variability in the supply of erodible sediment is the primary factor affecting near-bottom SSC. Natural physical processes in San Pablo Bay are more areally extensive, of equal or longer duration, and as frequent as dredging operations (when occurring), and they affect SSC at the tidal time scale. Natural processes control SSC at Point San Pablo even when dredging operations are occurring.

The banana code—natural blend processing in the olfactory circuitry of Drosophila melanogaster

PubMed Central

Schubert, Marco; Hansson, Bill S.; Sachse, Silke

2014-01-01

Odor information is predominantly perceived as complex odor blends. For Drosophila melanogaster one of the most attractive blends is emitted by an over-ripe banana. To analyze how the fly's olfactory system processes natural blends we combined the experimental advantages of gas chromatography and functional imaging (GC-I). In this way, natural banana compounds were presented successively to the fly antenna in close to natural occurring concentrations. This technique allowed us to identify the active odor components, use these compounds as stimuli and measure odor-induced Ca2+ signals in input and output neurons of the Drosophila antennal lobe (AL), the first olfactory neuropil. We demonstrate that mixture interactions of a natural blend are very rare and occur only at the AL output level resulting in a surprisingly linear blend representation. However, the information regarding single components is strongly modulated by the olfactory circuitry within the AL leading to a higher similarity between the representation of individual components and the banana blend. This observed modulation might tune the olfactory system in a way to distinctively categorize odor components and improve the detection of suitable food sources. Functional GC-I thus enables analysis of virtually any unknown natural odorant blend and its components in their relative occurring concentrations and allows characterization of neuronal responses of complete neural assemblies. This technique can be seen as a valuable complementary method to classical GC/electrophysiology techniques, and will be a highly useful tool in future investigations of insect-insect and insect-plant chemical interactions. PMID:24600405

Nature inspires sensors to do more with less.

PubMed

Mulvaney, Shawn P; Sheehan, Paul E

2014-10-28

The world is filled with widely varying chemical, physical, and biological stimuli. Over millennia, organisms have refined their senses to cope with these diverse stimuli, becoming virtuosos in differentiating closely related antigens, handling extremes in concentration, resetting the spent sensing mechanisms, and processing the multiple data streams being generated. Nature successfully deals with both repeating and new stimuli, demonstrating great adaptability when confronted with the latter. Interestingly, nature accomplishes these feats using a fairly simple toolbox. The sensors community continues to draw inspiration from nature's example: just look at the antibodies used as biosensor capture agents or the neural networks that process multivariate data streams. Indeed, many successful sensors have been built by simply mimicking natural systems. However, some of the most exciting breakthroughs occur when the community moves beyond mimicking nature and learns to use nature's tools in innovative ways.

Face processing regions are sensitive to distinct aspects of temporal sequence in facial dynamics.

PubMed

Reinl, Maren; Bartels, Andreas

2014-11-15

Facial movement conveys important information for social interactions, yet its neural processing is poorly understood. Computational models propose that shape- and temporal sequence sensitive mechanisms interact in processing dynamic faces. While face processing regions are known to respond to facial movement, their sensitivity to particular temporal sequences has barely been studied. Here we used fMRI to examine the sensitivity of human face-processing regions to two aspects of directionality in facial movement trajectories. We presented genuine movie recordings of increasing and decreasing fear expressions, each of which were played in natural or reversed frame order. This two-by-two factorial design matched low-level visual properties, static content and motion energy within each factor, emotion-direction (increasing or decreasing emotion) and timeline (natural versus artificial). The results showed sensitivity for emotion-direction in FFA, which was timeline-dependent as it only occurred within the natural frame order, and sensitivity to timeline in the STS, which was emotion-direction-dependent as it only occurred for decreased fear. The occipital face area (OFA) was sensitive to the factor timeline. These findings reveal interacting temporal sequence sensitive mechanisms that are responsive to both ecological meaning and to prototypical unfolding of facial dynamics. These mechanisms are temporally directional, provide socially relevant information regarding emotional state or naturalness of behavior, and agree with predictions from modeling and predictive coding theory. Copyright © 2014 The Authors. Published by Elsevier Inc. All rights reserved.

Genesis of hexavalent chromium from natural sources in soil and groundwater.

PubMed

Oze, Christopher; Bird, Dennis K; Fendorf, Scott

2007-04-17

Naturally occurring Cr(VI) has recently been reported in ground and surface waters. Rock strata rich in Cr(III)-bearing minerals, in particular chromite, are universally found in these areas that occur near convergent plate margins. Here we report experiments demonstrating accelerated dissolution of chromite and subsequent oxidation of Cr(III) to aqueous Cr(VI) in the presence of birnessite, a common manganese mineral, explaining the generation of Cr(VI) by a Cr(III)-bearing mineral considered geochemically inert. Our results demonstrate that Cr(III) within ultramafic- and serpentinite-derived soils/sediments can be oxidized and dissolved through natural processes, leading to hazardous levels of aqueous Cr(VI) in surface and groundwater.

Genesis of hexavalent chromium from natural sources in soil and groundwater

PubMed Central

Oze, Christopher; Bird, Dennis K.; Fendorf, Scott

2007-01-01

Naturally occurring Cr(VI) has recently been reported in ground and surface waters. Rock strata rich in Cr(III)-bearing minerals, in particular chromite, are universally found in these areas that occur near convergent plate margins. Here we report experiments demonstrating accelerated dissolution of chromite and subsequent oxidation of Cr(III) to aqueous Cr(VI) in the presence of birnessite, a common manganese mineral, explaining the generation of Cr(VI) by a Cr(III)-bearing mineral considered geochemically inert. Our results demonstrate that Cr(III) within ultramafic- and serpentinite-derived soils/sediments can be oxidized and dissolved through natural processes, leading to hazardous levels of aqueous Cr(VI) in surface and groundwater. PMID:17420454

Quality Assurance Project Plan For Verification of ANDalyze Lead100 Test Kit and AND1000 Fluorimeter

EPA Science Inventory

Lead (Pb) is a naturally occurring metal in the aquatic environment; however, most Pb contamination of concern arises from anthropogenic sources (such as deposition of Pb dust from combustion processes in natural waterways or due to its use in plumbing materials). Although Pb is...

Working memory at work: how the updating process alters the nature of working memory transfer.

PubMed

Zhang, Yanmin; Verhaeghen, Paul; Cerella, John

2012-01-01

In three N-Back experiments, we investigated components of the process of working memory (WM) updating, more specifically access to items stored outside the focus of attention and transfer from the focus to the region of WM outside the focus. We used stimulus complexity as a marker. We found that when WM transfer occurred under full attention, it was slow and highly sensitive to stimulus complexity, much more so than WM access. When transfer occurred in conjunction with access, however, it was fast and no longer sensitive to stimulus complexity. Thus the updating context altered the nature of WM processing: The dual-task situation (transfer in conjunction with access) drove memory transfer into a more efficient mode, indifferent to stimulus complexity. In contrast, access times consistently increased with complexity, unaffected by the processing context. This study reinforces recent reports that retrieval is a (perhaps the) key component of working memory functioning. Copyright © 2011 Elsevier B.V. All rights reserved.

Working Memory at Work: How the Updating Process Alters the Nature of Working Memory Transfer

PubMed Central

Zhang, Yanmin; Verhaeghen, Paul; Cerella, John

2011-01-01

In three N-Back experiments, we investigated components of the process of working memory (WM) updating, more specifically access to items stored outside the focus of attention and transfer from the focus to the region of WM outside the focus. We used stimulus complexity as a marker. We found that when WM transfer occurred under full attention, it was slow and highly sensitive to stimulus complexity, much more so than WM access. When transfer occurred in conjunction with access, however, it was fast and no longer sensitive to stimulus complexity. Thus the updating context altered the nature of WM processing: The dual-task situation (transfer in conjunction with access) drove memory transfer into a more efficient mode, indifferent to stimulus complexity. In contrast, access times consistently increased with complexity, unaffected by the processing context. This study reinforces recent reports that retrieval is a (perhaps the) key component of working memory functioning. PMID:22105718

Evolution of permafrost landscapes under technogenic impacts

NASA Astrophysics Data System (ADS)

Kerimov, A. G.; Grebenets, V. I.; Streletskiy, D. A.; Shiklomanov, N. I.; Nyland, K. E.

2014-12-01

Economic development of Russian Northern Regions on permafrost resulted in a new pattern of geocryological conditions, different from natural environment. This pattern is characterized by drastic landscape transformations; changes of heat and mass transfer in the permafrost/atmosphere system; and by engineering and technical pressure upon the permafrost, leading to alteration of its physical, thermal and mechanical properties. In the northern cities this causes increase of ground temperature and intensification of hazardous cryogenic processes in areas under engineering development, reducing stability of geotechnical environment. For example, facility deformations in Norilsk in the last 15 years, became much more abundant than these revealed throughout the previous 50 years. Increase in accident risk for facilities (pipelines, industrial enterprises, etc.) enhances the technogenic pressure on permafrost of the territories under development, leading to the new milestone of changes in permafrost, i.e. to creation of a new set of geocryological conditions. Cryogenic processes within the urban cryolithozone are seldom similar with these under the natural conditions: they either occur more intensively or, vice versa, attenuate under technogenic impacts, new cryogenic processes and phenomena occur, which have not been typical for a given region hitherto. A geographical distribution, evolution and other features of cryogenic processes differ considerably from natural conditions or are unprecedented at all. Peculiar natural-technogenic geocryological complices (NTGC) are formed in the urban centers, which are remarkable by the vector of permafrost evolution, by the set of cryogenic processes, by temperature trends and the other characteristics. NTGC types depend on initial natural settings and on kinds, intensity and duration of technogenic pressure. Our field surveys of permafrost and geological conditions resulted in mapping of 17 NTGC types in Norilsk, 11 types in Yamburg gas field, and 32 types along gas and oil pipelines in the north of Western Siberia. NTGC dynamics, depending on climate change, the scale of urban system, on the set of its elements and on duration of impact upon nature, and on degree of stability of natural permafrost, attracts the particular interest.

Size-dependent surface phase change of lithium iron phosphate during carbon coating

NASA Astrophysics Data System (ADS)

Wang, Jiajun; Yang, Jinli; Tang, Yongji; Liu, Jian; Zhang, Yong; Liang, Guoxian; Gauthier, Michel; Karen Chen-Wiegart, Yu-Chen; Norouzi Banis, Mohammad; Li, Xifei; Li, Ruying; Wang, Jun; Sham, T. K.; Sun, Xueliang

2014-03-01

Carbon coating is a simple, effective and common technique for improving the conductivity of active materials in lithium ion batteries. However, carbon coating provides a strong reducing atmosphere and many factors remain unclear concerning the interface nature and underlying interaction mechanism that occurs between carbon and the active materials. Here, we present a size-dependent surface phase change occurring in lithium iron phosphate during the carbon coating process. Intriguingly, nanoscale particles exhibit an extremely high stability during the carbon coating process, whereas microscale particles display a direct visualization of surface phase changes occurring at the interface at elevated temperatures. Our findings provide a comprehensive understanding of the effect of particle size during carbon coating and the interface interaction that occurs on carbon-coated battery material—allowing for further improvement in materials synthesis and manufacturing processes for advanced battery materials.

A reactive transport modelling approach to assess the leaching potential of hydraulic fracturing fluids associated with coal seam gas extraction

NASA Astrophysics Data System (ADS)

Mallants, Dirk; Simunek, Jirka; Gerke, Kirill

2015-04-01

Coal Seam Gas production generates large volumes of "produced" water that may contain compounds originating from the use of hydraulic fracturing fluids. Such produced water also contains elevated concentrations of naturally occurring inorganic and organic compounds, and usually has a high salinity. Leaching of produced water from storage ponds may occur as a result of flooding or containment failure. Some produced water is used for irrigation of specific crops tolerant to elevated salt levels. These chemicals may potentially contaminate soil, shallow groundwater, and groundwater, as well as receiving surface waters. This paper presents an application of scenario modelling using the reactive transport model for variably-saturated media HP1 (coupled HYDRUS-1D and PHREEQC). We evaluate the fate of hydraulic fracturing chemicals and naturally occurring chemicals in soil as a result of unintentional release from storage ponds or when produced water from Coal Seam Gas operations is used in irrigation practices. We present a review of exposure pathways and relevant hydro-bio-geo-chemical processes, a collation of physico-chemical properties of organic/inorganic contaminants as input to a set of generic simulations of transport and attenuation in variably saturated soil profiles. We demonstrate the ability to model the coupled processes of flow and transport in soil of contaminants associated with hydraulic fracturing fluids and naturally occurring contaminants.

Radiochemical Analyses of the Filter Cake, Granular Activated Carbon, and Treated Ground Water from the DTSC Stringfellow Superfund Site Pretreatment Plant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Esser, B K; McConachie, W; Fischer, R

2005-09-16

The Department of Toxic Substance Control (DTSC) requested that Lawrence Livermore National Laboratory (LLNL) evaluate the treatment process currently employed at the Department's Stringfellow Superfund Site Pretreatment Plant (PTP) site to determine if wastes originating from the site were properly managed with regards to their radioactivity. In order to evaluate the current management strategy, LLNL suggested that DTSC characterize the effluents from the waste treatment system for radionuclide content. A sampling plan was developed; samples were collected and analyzed for radioactive constituents. Following is brief summary of those results and what implications for waste characterization may be made. (1) Themore » sampling and analysis provides strong evidence that the radionuclides present are Naturally Occurring Radioactive Material (NORM). (2) The greatest source of radioactivity in the samples was naturally occurring uranium. The sample results indicate that the uranium concentration in the filter cake is higher than the Granular Activated Carbon (GAC) samples. (11 -14 and 2-6 ppm respectively). (3) No radiologic background for geologic materials has been established for the Stringfellow site, and comprehensive testing of the process stream has not been conducted. Without site-specific testing of geologic materials and waste process streams, it is not possible to conclude if filter cake and spent GAC samples contain radioactivity concentrated above natural background levels, or if radionuclides are being concentrated by the waste treatment process. Recommendation: The regulation of Technologically Enhanced, Naturally Occurring Radioactive Materials (T-NORM) is complex. Since the results of this study do not conclusively demonstrate that natural radioactive materials have not been concentrated by the treatment process it is recommended that the DTSC consult with the Department of Health Services (DHS) Radiological Health Branch to determine if any further action is warranted. If it were deemed desirable to establish a background for the Stringfellow setting LLNL would recommend that additional samples be taken and analyzed by LLNL using the same methods presented in this report.« less

Uranium Mining and Norm in North America-Some Perspectives on Occupational Radiation Exposure.

PubMed

Brown, Steven H; Chambers, Douglas B

2017-07-01

All soils and rocks contain naturally occurring radioactive materials (NORM). Many ores and raw materials contain relatively elevated levels of natural radionuclides, and processing such materials can further increase the concentrations of naturally occurring radionuclides. In the U.S., these materials are sometimes referred to as technologically-enhanced naturally occurring radioactive materials (TENORM). Examples of NORM minerals include uranium ores, monazite (a source of rare earth minerals), and phosphate rock used to produce phosphate fertilizer. The processing of these materials has the potential to result in above-background radiation exposure to workers. Following a brief review of the sources and potential for worker exposure from NORM in these varied industries, this paper will then present an overview of uranium mining and recovery in North America, including discussion on the mining methods currently being used for both conventional (underground, open pit) and in situ leach (ISL), also referred to as In Situ Recovery (ISR), and the production of NORM materials and wastes associated with these uranium recovery methods. The radiological composition of the NORM products and wastes produced and recent data on radiological exposures received by workers in the North American uranium recovery industry are then described. The paper also identifies the responsible government agencies in the U.S. and Canada assigned the authority to regulate and control occupational exposure from these NORM materials.

Metabolic adaptation and in situ attenuation of chlorinated ethenes by naturally occurring microorganisms in a fractured dolomite aquifer near Niagara Falls, New York

USGS Publications Warehouse

Yager, R.M.; Bilotta, S.E.; Mann, C.L.; Madsen, E.L.

1997-01-01

A combination of hydrogeological, geochemical, and microbiological methods was used to document the biotransformation of trichloroethene (TCE) to ethene, a completely dechlorinated and environmentally benign compound, by naturally occurring microorganisms within a fractured dolomite aquifer. Analyses of groundwater samples showed that three microbially produced TCE breakdown products (cis-1,2-dichloroethene, vinyl chloride, and ethene) were present in the contaminant plume. Hydrogen (H2) concentrations in groundwater indicated that iron reduction was the predominant terminal electron-accepting process in the most contaminated geologic zone of the site. Laboratory microcosms prepared with groundwater demonstrated complete sequential dechlorination of TCE to ethene. Microcosm assays also revealed that reductive dechlorination activity was present in waters from the center but not from the periphery of the contaminant plume. This dechlorination activity indicated that naturally occurring microorganisms have adapted to utilize chlorinated ethenes and suggested that dehalorespiring rather than cometabolic, microbial processes were the cause of the dechlorination. The addition of pulverized dolomite to microcosms enhanced the rate of reductive dechlorination, suggesting that hydrocarbons in the dolomite aquifer may serve as electron donors to drive microbially mediated reductive dechlorination reactions. Biodegradation of the chlorinated ethenes appears to contribute significantly to decontamination of the site.A combination of hydrogeological, geochemical, and microbiological methods was used to document the biotransformation of trichloroethene (TCE) to ethene, a completely dechlorinated and environmentally benign compound, by naturally occurring microorganisms within a fractured dolomite aquifer. Analyses of groundwater samples showed that three microbially produced TCE breakdown products (cis-1,2-dichloroethene, vinyl chloride, and ethene) were present in the contaminant plume. Hydrogen (H2) concentrations in groundwater indicated that iron reduction was the predominant terminal electron-accepting process in the most contaminated geologic zone of the site. Laboratory microcosms prepared with groundwater demonstrated complete sequential dechlorination of TCE to ethene. Microcosm assays also revealed that reductive dechlorination activity was present in waters from the center but not from the periphery of the contaminant plume. This dechlorination activity indicated that naturally occurring microorganisms have adapted to utilize chlorinated ethenes and suggested that dehalorespiring rather than cometabolic, microbial processes were the cause of the dechlorination. The addition of pulverized dolomite to microcosms enhanced the rate of reductive dechlorination, suggesting that hydrocarbons in the dolomite aquifer may serve as electron donors to drive microbially mediated reductive dechlorination reactions. Biodegradation of the chlorinated ethenes appears to contribute significantly to decontamination of the site.

Grow Your Own Copper Deposit

ERIC Educational Resources Information Center

Corcoran, Timothy John

2009-01-01

Crystals are beautiful structures--yet they occur naturally in dirty and remote places. In the inquiry-based activity described here, students will enjoy the process of creating their own crystals and using microscopes to examine them. It demonstrates the process of mineral concentration and deposition. Upon completing this activity, students…

Interfacial interaction between the epoxidized natural rubber and silica in natural rubber/silica composites

NASA Astrophysics Data System (ADS)

Xu, Tiwen; Jia, Zhixin; Luo, Yuanfang; Jia, Demin; Peng, Zheng

2015-02-01

The epoxidized natural rubber (ENR) as an interfacial modifier was used to improve the mechanical and dynamical mechanical properties of NR/silica composites. In order to reveal the interaction mechanism between ENR and silica, the ENR/Silica model compound was prepared by using an open mill and the interfacial interaction of ENR with silica was investigated by Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), X-ray diffraction (XRD) and stress-strain testing. The results indicated that the ring-opening reaction occurs between the epoxy groups of ENR chains and Si-OH groups on the silica surfaces and the covalent bonds are formed between two phases, which can improve the dispersion of silica in the rubber matrix and enhance the interfacial combination between rubber and silica. The ring-opening reaction occurs not only in vulcanization process but also in mixing process, meanwhile, the latter seems to be more important due to the simultaneous effects of mechanical force and temperature.

Super-emitters in natural gas infrastructure are caused by abnormal process conditions

NASA Astrophysics Data System (ADS)

Zavala-Araiza, Daniel; Alvarez, Ramón A.; Lyon, David R.; Allen, David T.; Marchese, Anthony J.; Zimmerle, Daniel J.; Hamburg, Steven P.

2017-01-01

Effectively mitigating methane emissions from the natural gas supply chain requires addressing the disproportionate influence of high-emitting sources. Here we use a Monte Carlo simulation to aggregate methane emissions from all components on natural gas production sites in the Barnett Shale production region (Texas). Our total emission estimates are two-thirds of those derived from independent site-based measurements. Although some high-emitting operations occur by design (condensate flashing and liquid unloadings), they occur more than an order of magnitude less frequently than required to explain the reported frequency at which high site-based emissions are observed. We conclude that the occurrence of abnormal process conditions (for example, malfunctions upstream of the point of emissions; equipment issues) cause additional emissions that explain the gap between component-based and site-based emissions. Such abnormal conditions can cause a substantial proportion of a site's gas production to be emitted to the atmosphere and are the defining attribute of super-emitting sites.

TENORM: Bauxite and Alumina Production Wastes

EPA Pesticide Factsheets

Bauxite is used to produce alumina, which is then used to produce aluminum. Naturally-occurring radioactivity in bauxite ores is concentrated during the refining process, creating TENORM in bauxite refining residuals.

Technologically enhanced naturally occurring radioactive materials.

PubMed

Vearrier, David; Curtis, John A; Greenberg, Michael I

2009-05-01

Naturally occurring radioactive materials (NORM) are ubiquitous throughout the earth's crust. Human manipulation of NORM for economic ends, such as mining, ore processing, fossil fuel extraction, and commercial aviation, may lead to what is known as "technologically enhanced naturally occurring radioactive materials," often called TENORM. The existence of TENORM results in an increased risk for human exposure to radioactivity. Workers in TENORM-producing industries may be occupationally exposed to ionizing radiation. TENORM industries may release significant amounts of radioactive material into the environment resulting in the potential for widespread exposure to ionizing radiation. These industries include mining, phosphate processing, metal ore processing, heavy mineral sand processing, titanium pigment production, fossil fuel extraction and combustion, manufacture of building materials, thorium compounds, aviation, and scrap metal processing. A search of the PubMed database ( www.pubmed.com ) and Ovid Medline database ( ovidsp.tx.ovid.com ) was performed using a variety of search terms including NORM, TENORM, and occupational radiation exposure. A total of 133 articles were identified, retrieved, and reviewed. Seventy-three peer-reviewed articles were chosen to be cited in this review. A number of studies have evaluated the extent of ionizing radiation exposure both among workers and the general public due to TENORM. Quantification of radiation exposure is limited because of modeling constraints. In some occupational settings, an increased risk of cancer has been reported and postulated to be secondary to exposure to TENORM, though these reports have not been validated using toxicological principles. NORM and TENORM have the potential to cause important human health effects. It is important that these adverse health effects are evaluated using the basic principles of toxicology, including the magnitude and type of exposure, as well as threshold and dose response.

Changing with the climate

Treesearch

Rhonda Mazza

2008-01-01

Carbon is a naturally occurring compound, essential to life on this planet. We exhale it, while plants absorb it as part of the photosynthetic process. Human activities have altered the carbon balance, however, and as a result have triggered changes in climates around the world. By extracting and burning oil, coal, and natural gas, carbon that was locked in long-term...

Unweaving Misconceptions: Guided Learning, Simulations, and Misconceptions in Learning Principles of Natural Selection

ERIC Educational Resources Information Center

Weeks, Brian E.

2013-01-01

College students often come to the study of evolutionary biology with many misconceptions of how the processes of natural selection and speciation occur. How to relinquish these misconceptions with learners is a question that many educators face in introductory biology courses. Constructivism as a theoretical framework has become an accepted and…

Fire ecology in the southeastern United States

USGS Publications Warehouse

,

2000-01-01

Fire has played an important role in the structure of natural ecosystems throughout North America. As a natural process, fire helps clear away dead and dying plant matter and increases the production of native species that occur in fire prone habitats. It also reduces the invasion of exotic species and the succession to woody species in pitcher plant bogs, pine savannas, coastal prairies, marshes, and other natural plant communities of the southeastern United States.

Interaction of flavonoids, the naturally occurring antioxidants with different media: a UV-visible spectroscopic study.

PubMed

Naseem, Bushra; Shah, S W H; Hasan, Aurangzeb; Sakhawat Shah, S

2010-04-01

Quantitative parameters for interaction of flavonoids-the naturally occurring antioxidants, with solvents and surfactants are determined using UV-visible absorption spectroscopy. The availability of flavonoids; kaempferol, apigenin, kaempferide and rhamnetin in micelles of sodium dodecyl sulfate (SDS) is reflected in terms of partition coefficient, K(c). Thermodynamic calculations show that the process of transfer of flavonoid molecules to anionic micelles of SDS is energy efficient. A distortion in flavonoid's morphology occurs in case of kaempferol and apigenin in surfactant and water, exhibited in terms of a new band in the UV region of electronic spectra of these flavonoids. The partition coefficients of structurally related flavonoids are correlated with their antioxidant activities. Copyright 2010 Elsevier B.V. All rights reserved.

Rhythms of Dialogue and Referential Activity: Implicit Process across Procedural and Verbal Realms

ERIC Educational Resources Information Center

Ritter, Michael S.

2009-01-01

This work examines the relationship between implicit procedural and implicit verbal processes as they occur in natural adult conversation. Theoretical insights and empirical findings are rooted in a move towards integration of Bucci's "Referential Activity" (RA) and "Multiple Code" perspectives and Beebe and Jaffe's…

Naturally Occurring Food Toxins

PubMed Central

Dolan, Laurie C.; Matulka, Ray A.; Burdock, George A.

2010-01-01

Although many foods contain toxins as a naturally-occurring constituent or, are formed as the result of handling or processing, the incidence of adverse reactions to food is relatively low. The low incidence of adverse effects is the result of some pragmatic solutions by the US Food and Drug Administration (FDA) and other regulatory agencies through the creative use of specifications, action levels, tolerances, warning labels and prohibitions. Manufacturers have also played a role by setting limits on certain substances and developing mitigation procedures for process-induced toxins. Regardless of measures taken by regulators and food producers to protect consumers from natural food toxins, consumption of small levels of these materials is unavoidable. Although the risk for toxicity due to consumption of food toxins is fairly low, there is always the possibility of toxicity due to contamination, overconsumption, allergy or an unpredictable idiosyncratic response. The purpose of this review is to provide a toxicological and regulatory overview of some of the toxins present in some commonly consumed foods, and where possible, discuss the steps that have been taken to reduce consumer exposure, many of which are possible because of the unique process of food regulation in the United States. PMID:22069686

DOE Office of Scientific and Technical Information (OSTI.GOV)

Osmanlioglu, Ahmet Erdal

Available in abstract form only. Full text of publication follows: Naturally occurring radioactive material (NORM) in concentrated forms arises both in industry and in nature where natural radioisotopes accumulate at particular sites. Technically enhanced naturally occurring radioactive materials (TE-NORM) often occurs in an acidic environment where precipitates containing radionuclides plate out onto pipe walls, filters, tank linings, etc. Because of the radionuclides are selectively deposited at these sites, radioactivity concentration is extremely higher than the natural concentration. This paper presents characterization and related considerations of TE-NORM wastes in Turkey. Generally, accumulation conditions tend to favour the build-up of radium. Asmore » radium is highly radio-toxic, handling, treatment, storage and disposal of such material requires careful management. Turkey has the only low level waste processing and storage facility (WPSF) in Istanbul. This facility has interim storage buildings and storage area for storage of packaged radioactive waste which are containing artificial radioisotopes, but there is an increasing demand for the storage to accept bulk concentrated TE-NORM wastes from iron-steel and related industries. Most of these wastes generated from scrap metal piles which are imported from other countries. These wastes generally contain radium. (authors)« less

Comparisons of in vitro root caries models.

PubMed

Wefel, J S; Heilman, J R; Jordan, T H

1995-01-01

The purpose of this article is to compare various model systems for the production of in vitro root caries and to assess their ability to simulate the naturally occurring root caries process. Partially saturated buffer models and gel models were evaluated using polarized light microscopy and both qualitative and quantitative microradiography. All model systems showed very similar lesion formation when examined under polarized light. When microradiographs were compared, the systems which contained fluoride, showed clear radiopaque bands within the lesion. The bands, which occurred only in the presence of fluoride, appeared to be due to remineralization. When using an in vitro system that simulates the natural root caries process, it is imperative to understand the components of the particular model, as well as its limitations, and to be aware of the need for more than one evaluative technique.

Fast response to fast-forwarding nature: instream large wood habitat restoration

Treesearch

Cheryl A. Hayhurst; William R. Short

2017-01-01

How quickly and in what way does a channel bed respond when large wood elements are introduced in a way that imitates natural wood loading processes (un-anchored or anchored by burial)? Using a design streamflow threshold for determining the size of key large wood elements, what changes in channel bed and habitat complexity occur after streamflow events above...

Photooxidation of chloride by oxide minerals: implications for perchlorate on Mars.

PubMed

Schuttlefield, Jennifer D; Sambur, Justin B; Gelwicks, Melissa; Eggleston, Carrick M; Parkinson, B A

2011-11-09

We show that highly oxidizing valence band holes, produced by ultraviolet (UV) illumination of naturally occurring semiconducting minerals, are capable of oxidizing chloride ion to perchlorate in aqueous solutions at higher rates than other known natural perchlorate production processes. Our results support an alternative to atmospheric reactions leading to the formation of high concentrations of perchlorate on Mars.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ross, J; Walt Kubilius, W; Thomas Kmetz, T

Resource Conservation and Recovery Act (RCRA) requirements for hazardous waste facilities include 30 years of post-closure monitoring. The use of an objective-based monitoring strategy allows for a significant reduction in the amount of groundwater monitoring required, as the groundwater remediation transitions from an active biosparging system to monitored natural attenuation. The lifecycle of groundwater activities at the landfill has progressed from detection monitoring and plume characterization, to active groundwater remediation, and now to monitored natural attenuation and postclosure monitoring. Thus, the objectives of the groundwater monitoring have changed accordingly. Characterization monitoring evaluated what biogeochemical natural attenuation processes were occurring andmore » determined that elevated levels of radium were naturally occurring. Process monitoring of the biosparging system required comprehensive sampling network up- and down-gradient of the horizontal wells to verify its effectiveness. Currently, the scope of monitoring and reporting can be significantly reduced as the objective is to demonstrate that the alternate concentration limits (ACL) are being met at the point of compliance wells and the maximum contaminant level (MCL) is being met at the surface water point of exposure. The proposed reduction is estimated to save about $2M over the course of the remaining 25 years of postclosure monitoring.« less

A Review of the Foundational Processes that Influence Beliefs in Climate Change: Opportunities for Environmental Education Research

ERIC Educational Resources Information Center

Brownlee, Matthew T.J.; Powell, Robert B.; Hallo, Jeffery C.

2013-01-01

Recently, many organizations involved in environmental education have initiated programs that aim to educate visitors or other publics who interact with nature-based resources about the impacts and landscape transformations occurring because of climatic changes. However, many psychological, human-evolutionary, and social-ecological processes that…

Biodegration of chlorinated ethenes

USGS Publications Warehouse

Bradley, Paul M.; Chapelle, Francis H.

2010-01-01

Biodegradation of chlorinated ethenes by naturally occurring or artificially enhanced processes is an important component of current site remediation strategies. At this writing, several microbial mechanisms for chlorinated ethene transformation and degradation have been identified. The purpose of this chapter is to briefly summarize the current understanding of those processes that lead to the biodegradation of chlorinated ethenes.

Shedding (Incoherent) Light on Quantum Effects in Light-Induced Biological Processes.

PubMed

Brumer, Paul

2018-05-18

Light-induced processes that occur in nature, such as photosynthesis and photoisomerization in the first steps in vision, are often studied in the laboratory using coherent pulsed laser sources, which induce time-dependent coherent wavepacket molecule dynamics. Nature, however, uses stationary incoherent thermal radiation, such as sunlight, leading to a totally different molecular response, the time-independent steady state. It is vital to appreciate this difference in order to assess the role of quantum coherence effects in biological systems. Developments in this area are discussed in detail.

Study of water recovery and solid waste processing for aerospace and domestic applications. Volume 1: Final report summary

NASA Technical Reports Server (NTRS)

Guarneri, C. A.; Reed, A.; Renman, R. E.

1972-01-01

This study of water reclamation and waste disposal is directed toward a more efficient utilization of natural resources. From an ecological standpoint improved methods of land use, water processing equipment, and ideal population profiles are investigated. Methods are described whereby significant reduction in water usage can be achieved by the adoption of presently available and practically applied technological concepts. Allowances are made for social, natural, and economic contingencies which are likely to occur up to the year 2000.

ECOSYSTEM GROWTH AND DEVELOPMENT

EPA Science Inventory

Thermodynamically, ecosystem growth and development is the process by which energy throughflow and stored biomass increase. Several proposed hypotheses describe the natural tendencies that occur as an ecosystem matures, and here, we consider five: minimum entropy production, maxi...

Nanoencapsulation of Aloe vera in Synthetic and Naturally Occurring Polymers by Electrohydrodynamic Processing of Interest in Food Technology and Bioactive Packaging.

PubMed

Torres-Giner, Sergio; Wilkanowicz, Sabina; Melendez-Rodriguez, Beatriz; Lagaron, Jose M

2017-06-07

This work originally reports on the use of electrohydrodynamic processing (EHDP) to encapsulate Aloe vera (AV, Aloe barbadensis Miller) using both synthetic polymers, i.e., polyvinylpyrrolidone (PVP) and poly(vinyl alcohol) (PVOH), and naturally occurring polymers, i.e., barley starch (BS), whey protein concentrate (WPC), and maltodextrin. The AV leaf juice was used as the water-based solvent for EHDP, and the resultant biopolymer solution properties were evaluated to determine their effect on the process. Morphological analysis revealed that, at the optimal processing conditions, synthetic polymers mainly produced fiber-like structures, while naturally occurring polymers generated capsules. Average sizes ranged from 100 nm to above 3 μm. As a result of their different and optimal morphology and, hence, higher AV content, PVP, in the form of nanofibers, and WPC, of nanocapsules, were further selected to study the AV stability against ultraviolet (UV) light exposure. Fourier transform infrared (FTIR) spectroscopy confirmed the successful encapsulation of AV in the biopolymer matrices, presenting both encapsulants a high chemical interaction with the bioactive components. Ultraviolet-visible (UV-vis) spectroscopy showed that, while PVP nanofibers offered a poor effect on the AV degradation during UV light exposure (∼10% of stability after 5 h), WPC nanobeads delivered excellent protection (stability of >95% after 6 h). This was ascribed to positive interactions between WPC and the hydrophilic components of AV and the inherent UV-blocking and oxygen barrier properties provided by the protein. Therefore, electrospraying of food hydrocolloids interestingly appears as a novel potential nanotechnology tool toward the formulation of more stable functional foods and nutraceuticals.

Diels–Alder reactions of myrcene using intensified continuous-flow reactors

PubMed Central

Álvarez-Diéguez, Miguel Á; Kohl, Thomas M; Tsanaktsidis, John

2017-01-01

This work describes the Diels–Alder reaction of the naturally occurring substituted butadiene, myrcene, with a range of different naturally occurring and synthetic dienophiles. The synthesis of the Diels–Alder adduct from myrcene and acrylic acid, containing surfactant properties, was scaled-up in a plate-type continuous-flow reactor with a volume of 105 mL to a throughput of 2.79 kg of the final product per day. This continuous-flow approach provides a facile alternative scale-up route to conventional batch processing, and it helps to intensify the synthesis protocol by applying higher reaction temperatures and shorter reaction times. PMID:28228853

Parallel asynchronous systems and image processing algorithms

NASA Technical Reports Server (NTRS)

Coon, D. D.; Perera, A. G. U.

1989-01-01

A new hardware approach to implementation of image processing algorithms is described. The approach is based on silicon devices which would permit an independent analog processing channel to be dedicated to evey pixel. A laminar architecture consisting of a stack of planar arrays of the device would form a two-dimensional array processor with a 2-D array of inputs located directly behind a focal plane detector array. A 2-D image data stream would propagate in neuronlike asynchronous pulse coded form through the laminar processor. Such systems would integrate image acquisition and image processing. Acquisition and processing would be performed concurrently as in natural vision systems. The research is aimed at implementation of algorithms, such as the intensity dependent summation algorithm and pyramid processing structures, which are motivated by the operation of natural vision systems. Implementation of natural vision algorithms would benefit from the use of neuronlike information coding and the laminar, 2-D parallel, vision system type architecture. Besides providing a neural network framework for implementation of natural vision algorithms, a 2-D parallel approach could eliminate the serial bottleneck of conventional processing systems. Conversion to serial format would occur only after raw intensity data has been substantially processed. An interesting challenge arises from the fact that the mathematical formulation of natural vision algorithms does not specify the means of implementation, so that hardware implementation poses intriguing questions involving vision science.

Natural and anthropic processes controlling groundwater hydrogeochemistry in a tourist destination in northeastern Brazil.

PubMed

Mattos, Jonatas Batista; Cruz, Manoel Jerônimo Moreira; De Paula, Francisco Carlos Fernandes; Sales, Elinaldo Fonseca

2018-06-12

The objective of this study was to analyze spatial-seasonal changes to identify the natural and anthropic processes that control groundwater hydrogeochemistry in urban aquifers in municipality of Lençóis (Bahia). Tourism is the main activity of this municipality, which is an important tourist destination in northeastern Brazil and which maintains its tourism infrastructure by using groundwater. Two field campaigns were conducted (dry and rainy seasons) in order to collect groundwater samples extracted from 15 tubular wells distributed over the urban area of the municipality. The Piper diagram, multivariate statistical analyses, and artificial neural networks indicated that there are two types of water (Na-Cl and Na-[Formula: see text] - ), which were divided into five different clusters. Seasonal variation was observed to significantly alter groundwater hydrogeochemistry. According to the Gibbs diagram, groundwater within the urban area of Lençóis belonged to the rainfall dominance, demonstrating low water-rock interaction. Hydrogeochemical modeling results suggested hydrolysis as the main natural factors controlling process. However, mineral dissolution also occurred in one of the clusters. Human-originated trace contamination by nitrate, chloride, and sulfate occurred in a zone of the urban area. This contamination was observed regardless of climate seasonality, indicating that the main controlling process for groundwater hydrochemistry in this region is wastewater mobilization (indirect artificial recharge).

Smart Dressings Based on Nanostructured Fibers Containing Natural Origin Antimicrobial, Anti-Inflammatory, and Regenerative Compounds

PubMed Central

Andreu, Vanesa; Mendoza, Gracia; Arruebo, Manuel; Irusta, Silvia

2015-01-01

A fast and effective wound healing process would substantially decrease medical costs, wound care supplies, and hospitalization significantly improving the patients’ quality of life. The search for effective therapeutic approaches seems to be imperative in order to avoid the aggravation of chronic wounds. In spite of all the efforts that have been made during the recent years towards the development of artificial wound dressings, none of the currently available options combine all the requirements necessary for quick and optimal cutaneous regeneration. Therefore, technological advances in the area of temporary and permanent smart dressings for wound care are required. The development of nanoscience and nanotechnology can improve the materials and designs used in topical wound care in order to efficiently release antimicrobial, anti-inflammatory and regenerative compounds speeding up the endogenous healing process. Nanostructured dressings can overcome the limitations of the current coverings and, separately, natural origin components can also overcome the drawbacks of current antibiotics and antiseptics (mainly cytotoxicity, antibiotic resistance, and allergies). The combination of natural origin components with demonstrated antibiotic, regenerative, or anti-inflammatory properties together with nanostructured materials is a promising approach to fulfil all the requirements needed for the next generation of bioactive wound dressings. Microbially compromised wounds have been treated with different essential oils, honey, cationic peptides, aloe vera, plant extracts, and other natural origin occurring antimicrobial, anti-inflammatory, and regenerative components but the available evidence is limited and insufficient to be able to draw reliable conclusions and to extrapolate those findings to the clinical practice. The evidence and some promising preliminary results indicate that future comparative studies are justified but instead of talking about the beneficial or inert effects of those natural origin occurring materials, the scientific community leads towards the identification of the main active components involved and their mechanism of action during the corresponding healing, antimicrobial, or regenerative processes and in carrying out systematic and comparative controlled tests. Once those natural origin components have been identified and their efficacy validated through solid clinical trials, their combination within nanostructured dressings can open up new avenues in the fabrication of bioactive dressings with outstanding characteristics for wound care. The motivation of this work is to analyze the state of the art in the use of different essential oils, honey, cationic peptides, aloe vera, plant extracts, and other natural origin occurring materials as antimicrobial, anti-inflammatory and regenerative components with the aim of clarifying their potential clinical use in bioactive dressings. We conclude that, for those natural occurring materials, more clinical trials are needed to reach a sufficient level of evidence as therapeutic agents for wound healing management. PMID:28793497

Engineering Design and Operation Report: Biological Treatment Process for the Removal of Ammonia from a Small Drinking Water System in Iowa: Pilot to Full-Scale

EPA Science Inventory

Many regions in the United States have excessive levels of ammonia in their drinking water sources (e.g., ground and surface waters) as a result of naturally occurring processes, agricultural and urban runoff, concentrated animal feeding operations, municipal wastewater treatment...

Innovative Biological Treatment Process for the Removal of Ammonia, Arsenic, Iron and Manganese from a Small Drinking Water System in Gilbert, Iowa (Phase 1: Pilot Evaluation)

EPA Science Inventory

Many regions in the United States have excessive levels of ammonia in their drinking water sources (e.g., ground and surface waters) as a result of naturally occurring processes, agricultural and urban runoff, concentrated animal feeding operations, municipal wastewater treatment...

Forest health in the Blue Mountains: an plant ecologist's perspective on ecosystem processes and biological diversity.

Treesearch

Charles G. Johnson

1994-01-01

Natural disturbances are important to ecosystem processes. Disturbances historically have occurred in the vegetation of the Blue Mountain area of northeastern Oregon and southeastern Washington. The primary modifying events that historically have cycled through most of its plant communities are fire, grazing and browsing, insect and disease epidemics, windthrow,...

Development and Application of Learning Materials to Help Students Understand Ten Statements Describing the Nature of Scientific Observation

ERIC Educational Resources Information Center

Kim, Sangsoo; Park, Jongwon

2018-01-01

Observing scientific events or objects is a complex process that occurs through the interaction between the observer's knowledge or expectations, the surrounding context, physiological features of the human senses, scientific inquiry processes, and the use of observational instruments. Scientific observation has various features specific to this…

Application of UV-irradiated Fe(III)-nitrilotriacetic acid (UV-Fe(III)NTA) and UV-NTA-Fenton systems to degrade model and natural occurring naphthenic acids.

PubMed

Zhang, Ying; Chelme-Ayala, Pamela; Klamerth, Nikolaus; Gamal El-Din, Mohamed

2017-07-01

Naphthenic acids (NAs) are a highly complex mixture of organic compounds naturally present in bitumen and identified as the primary toxic constituent of oil sands process-affected water (OSPW). This work investigated the degradation of cyclohexanoic acid (CHA), a model NA compound, and natural occurring NAs during the UV photolysis of Fe(III)-nitrilotriacetic acid (UV-Fe(III)NTA) and UV-NTA-Fenton processes. The results indicated that in the UV-Fe(III)NTA process at pH 8, the CHA removal increased with increasing NTA dose (0.18, 0.36 and 0.72 mM), while it was independent of the Fe(III) dose (0.09, 0.18 and 0.36 mM). Moreover, the three Fe concentrations had no influence on the photolysis of the Fe(III)NTA complex. The main responsible species for the CHA degradation was hydroxyl radical (OH), and the role of dissolved O 2 in the OH generation was found to be negligible. Real OSPW was treated with the UV-Fe(III)NTA and UV-NTA-Fenton advanced oxidation processes (AOPs). The removals of classical NAs (O 2 -NAs), oxidized NAs with one additional oxygen atom (O 3 -NAs) and with two additional oxygen atoms (O 4 -NAs) were 44.5%, 21.3%, and 25.2% in the UV-Fe(III)NTA process, respectively, and 98.4%, 86.0%, and 81.0% in the UV-NTA-Fenton process, respectively. There was no influence of O 2 on the NA removal in these two processes. The results also confirmed the high reactivity of the O 2 -NA species with more carbons and increasing number of rings or double bond equivalents. This work opens a new window for the possible treatment of OSPW at natural pH using these AOPs. Copyright © 2017 Elsevier Ltd. All rights reserved.

Freshwater processing of terrestrial dissolved organic matter: What governs lability?

NASA Astrophysics Data System (ADS)

D'Andrilli, J.; Smith, H. J.; Junker, J. R.; Scholl, E. A.; Foreman, C. M.

2016-12-01

Aquatic and terrestrial ecosystems are linked through the transfer of energy and materials. Allochthonous organic matter (OM) is central to freshwater ecosystem function, influencing local food webs, trophic state, and nutrient availability. In order to understand the nature and fate of OM from inland headwaters to the open ocean, it is imperative to understand the links between OM lability and ecosystem function. Thus, biological, chemical, and physical factors need to be evaluated together to inform our understanding of environmental lability. We performed a laboratory processing experiment on naturally occurring OM leachates from riparian leaves, grasses, and pine needles. Measures of water chemistry, OM optical and molecular characterization, bacterial abundances, microbial assemblage composition, respiration, and C:N:P were integrated to discern the nature and fate of labile and recalcitrant OM in a freshwater stream. Peak processing of all OM sources in the stream water occurred after two days, with spikes in bacterial cell abundances, respiration rates, microbial assemblage shifts, and maximum C utilization. Respiration rates and microbial assemblages were dependent on the degree of lability of the OM molecular composition. Within the first few days, no differences in respiration rates were observed between leachate sources, however, beyond day five, the rates diverged with C processing efficiency correlated with OM lability. Originally comprised of amino acid-like, labile fluorescent species, the inoculated stream water OM became more recalcitrant after 16 days, indicating humification processing over time. Our study highlights the importance of interdisciplinary approaches for understanding the processing and fate of OM in aquatic ecosystems.

Making Cosmic Connections in the Nature of Science

NASA Astrophysics Data System (ADS)

Androes, D. L.

2011-09-01

Presenting the rich heritage of astronomy includes exposing the process of science, warts and all. In the quest to comprehensively cover science content, the nature of science is often neglected. A cursory inclusion of the nature of science generally showcases in the lives and times of the Copernican Revolution - and rightly so. Astronomy owes its mark of fame in all other disciplines to the radical shift in thinking about our place in the cosmos that occurred in the late 1500s and early 1600s. However, the nature of science offers a much broader range of connections between science objectives and course content.

Introduction to Pharmaceuticals and Personal Care Products (PPCPS)

EPA Science Inventory

Those chemical pollutants that are regulated under various international, federal, and state programs represent but a small fraction of the universe of chemicals that occur in the environment as a result of both natural processes and human influence.

Are We Educating Only Half of the Brain?

ERIC Educational Resources Information Center

Gowan, J. C., Ed.

1979-01-01

The author cites experts on the nature of right hemisphere imagery, the vehicle through which incubation (the second component of creativity) produces creativity, and explores conditions under which imagery occurs. A summarization of the incubation process is provided. (PHR)

Detection and characterization of foodborne pathogenic bacteria with hyperspectral microscope imaging

USDA-ARS?s Scientific Manuscript database

Rapid detection and identification of pathogenic microorganisms naturally occurring during food processing are important in developing intervention and verification strategies. In the poultry industry, contamination of poultry meat with foodborne pathogens (especially, Salmonella and Campylobacter) ...

Proximal soil sensing: global perspective

USDA-ARS?s Scientific Manuscript database

As a result of a number of naturally occurring processes and cultural practices, the characteristics of soils demonstrate substantial spatial heterogeneity that affects current land use. From infrastructure development to agriculture, spatial variability in soils must be taken into account in order ...

Engineered biosealant producing inorganic and organic biopolymers

USDA-ARS?s Scientific Manuscript database

Microbiologically induced calcium carbonate precipitation (MICCP) is a naturally occurring biological process that has shown its potential in remediation of a wide range of structural damages including concrete cracks. MICCP involves sequential microbiological and chemical reactions, such as urea h...

BIOBASED MATERIALS

EPA Science Inventory

Biobased materials refer to products that mainly consist of a substance (or substances) derived from living matter (biomass) and either occur naturally or are synthesized, or it may refer to products made by processes that use biomass. Following a strict definition, many common m...

Mineral systems and the thermodynamics of selenites and selenates in the oxidation zone of sulfide ores - a review

NASA Astrophysics Data System (ADS)

Charykova, Marina V.; Krivovichev, Vladimir G.

2017-02-01

Contemporary mineralogy and geochemistry are concerned with understanding and deciphering processes that occur near the surface of the Earth. These processes are especially important for resolving ecological challenges and developing principles of good environmental management. Selenium oxysalts, selenites and selenates, are relatively rare as minerals; there are presently only 34 known mineral species. Thirty-one "pure" selenites, which contain only selenite anionic groups, are known to occur naturally. The other three minerals each contain two anionic groups: selenate and selenite (schmiederite), selenate and sulphate (olsacherite), and selenate and iodate (carlosruizite).

A Goal-Oriented Model of Natural Language Interaction

DTIC Science & Technology

1977-01-01

AHSTKACT This report describes a research program in modeling human communication . The methodology involved selecting a single, naturally-occurring...knowledge is seldom used in the design process. Human communication skills have not bee’’ characferi?ed at a level of detail appropriate for guiding design...necessarily combine to give a complete picture of human communication . Experience over several more dialogues may suggest that one or all be replaced

Natural and accelerated recovery from brain damage: experimental and theoretical approaches.

PubMed

Andersen, Richard A; Schieber, Marc H; Thakor, Nitish; Loeb, Gerald E

2012-03-01

The goal of the Caltech group is to gain insight into the processes that occur within the primate nervous system during dexterous reaching and grasping and to see whether natural recovery from local brain damage can be accelerated by artificial means. We will create computational models of the nervous system embodying this insight and explain a variety of clinically observed neurological deficits in human subjects using these models.

Role of natural analogs in performance assessment of nuclear waste repositories

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sagar, B.; Wittmeyer, G.W.

1995-09-01

Mathematical models of the flow of water and transport of radionuclides in porous media will be used to assess the ability of deep geologic repositories to safely contain nuclear waste. These models must, in some sense, be validated to ensure that they adequately describe the physical processes occurring within the repository and its geologic setting. Inasmuch as the spatial and temporal scales over which these models must be applied in performance assessment are very large, validation of these models against laboratory and small-scale field experiments may be considered inadequate. Natural analogs may provide validation data that are representative of physico-chemicalmore » processes that occur over spatial and temporal scales as large or larger than those relevant to repository design. The authors discuss the manner in which natural analog data may be used to increase confidence in performance assessment models and conclude that, while these data may be suitable for testing the basic laws governing flow and transport, there is insufficient control of boundary and initial conditions and forcing functions to permit quantitative validation of complex, spatially distributed flow and transport models. The authors also express their opinion that, for collecting adequate data from natural analogs, resources will have to be devoted to them that are much larger than are devoted to them at present.« less

Drift of surface and near-bottom waters of the San Francisco Bay system, California March 1970 through April 1971

USGS Publications Warehouse

Conomos, T.J.; McCulloch, D.S.; Peterson, D.H.; Carlson, P.R.

1972-01-01

The San Francisco Bay system is a complex estuary in which there is an interplay between natural chemical and physical processes, and changes resulting from the works of man. The bay is used for recreation, water-borne commerce, fishing, domestic and industrial waste disposal, and esthetic pleasure. Because some of these uses are competitive, it is desirable to adequately predict the impact of man's activities on this natural system. The reliability of such predictions will be strengthened by long-term observations directed toward understanding the natural processes occurring in the bay. This study is a compilation of one aspect of the U.S. Geological Survey's continuing investigations of the San Francisco Bay system.

Novel predictors of soil genesis following natural weathering processes of bauxite residues.

PubMed

Zhu, Feng; Xue, Shengguo; Hartley, William; Huang, Ling; Wu, Chuan; Li, Xiaofei

2016-02-01

Bauxite residue often has chemical and physical limitations to support plant growth, and improving its matrix properties is crucial to support sustainable vegetation in the long term. Spontaneous vegetation colonization on deposits in Central China, over a period of 20 years, has revealed that natural weathering processes may convert bauxite residue to a soil-like medium. Residue samples from different stacking ages were collected to determine the effect of natural processes on matrix properties over time. It was demonstrated that natural processes decreased pH (10.98 to 9.45), electrical conductivity (EC) (3.73 to 0.36 mS/cm), and exchangeable sodium percentage (ESP) (72.51 to 28.99 %), while increasing bulk density (1.91 to 1.39 g/cm(3)), improving the mean weight diameter (MWD) of water-stable aggregates (0.24 to 0.52 mm), and the proportion of >0.25-mm water-stable aggregates (19.91 to 50.73 %). The accumulation of organic carbon and the reduction of ESP and exchangeable Na had positive effects on soil aggregate formation, while exchangeable Ca and Mg were significantly beneficial to aggregation of water-stable aggregates. Climate, stacking time, and biological factors appear to improve the structure of bauxite residue. Our findings demonstrate soil genesis occurring following natural weathering processes of bauxite residues over time.

Colour agnosia impairs the recognition of natural but not of non-natural scenes.

PubMed

Nijboer, Tanja C W; Van Der Smagt, Maarten J; Van Zandvoort, Martine J E; De Haan, Edward H F

2007-03-01

Scene recognition can be enhanced by appropriate colour information, yet the level of visual processing at which colour exerts its effects is still unclear. It has been suggested that colour supports low-level sensory processing, while others have claimed that colour information aids semantic categorization and recognition of objects and scenes. We investigated the effect of colour on scene recognition in a case of colour agnosia, M.A.H. In a scene identification task, participants had to name images of natural or non-natural scenes in six different formats. Irrespective of scene format, M.A.H. was much slower on the natural than on the non-natural scenes. As expected, neither M.A.H. nor control participants showed any difference in performance for the non-natural scenes. However, for the natural scenes, appropriate colour facilitated scene recognition in control participants (i.e., shorter reaction times), whereas M.A.H.'s performance did not differ across formats. Our data thus support the hypothesis that the effect of colour occurs at the level of learned associations.

Radiochemical techniques for determining some naturally occurring radionuclides in marine environmental materials

NASA Astrophysics Data System (ADS)

Baker, C. W.

1984-06-01

The determination of some of the naturally-occurring, alpha-emitting radionuclides in marine environmental materials, is of interest for several reasons. Radium and radon nuclides are potentially useful as oceanographic tracers. Lead and thorium nuclides may be used to study sedimentation rates, mixing processes and bioturbation in sediments. Radium and polonium nuclides are incorporated into food chains and the data may provide a perspective against which to assess the significance, for marine organisms, of exposure to radiation in a marine radioactive waste disposal situation. This paper discusses the manner in which samples are taken, and the radiochemical methods which have been employed to measure the nuclides, together with some data produced.

Qualitative Information in Annual Reports & the Detection of Corporate Fraud: A Natural Language Processing Perspective

ERIC Educational Resources Information Center

Goel, Sunita

2009-01-01

High profile cases of fraudulent financial reporting such as those that occurred at Enron and WorldCom have shaken public confidence in the U.S. financial reporting process and have raised serious concerns about the roles of auditors, regulators, and analysts in financial reporting. In order to address these concerns and restore public confidence,…

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gaffney, Jeffrey

This is the final technical report. The project description is as follows: to determine the role of aerosol radiative forcing on climate, the processes that control their atmospheric concentrations must be understood, and aerosol sources need to be determined for mitigation. Measurements of naturally occurring radionuclides and stable isotopic signatures allow the sources, removal and transport processes, as well as atmospheric lifetimes of fine carbonaceous aerosols, to be evaluated.

PHARMACEUTICALS & PERSONAL CARE PRODUCTS AS ENVIRONMENTAL POLLUTANTS FROM EVERYDAY ACTIVITIES

EPA Science Inventory

Those chemical pollutants that are regulated under various international, federal, and state programs represent but a small fraction of the universe of chemicals that occur in the environment as a result of both natural processes and human influence.

A DATA SYSTEM FOR INTEGRATING DATA FROM LANDSCAPES, STREAMS AND ESTUARIES

EPA Science Inventory

Estuaries are natural integrators of substances and processes that occur internally and externally (watersheds, ocean, atmosphere). Watershed activities that contribute fresh water, nutrients, contaminants, and suspended solids have a strong effect on the health of estuaries. Res...

MONITORED NATURAL ATTENUATION FOR INORGANIC CONTAMINANT REMEDIATION IN GROUND WATER: MNA MECHANISMS

EPA Science Inventory

This presentation discusses the various mechanisms that are recognized to result in the attenuation of inorganic contaminants in ground water. The presentation will provide details on the contaminant sequestration processes that occur at the mineral-water interface.

Pectin in foods

USDA-ARS?s Scientific Manuscript database

Pectin, a complex polysaccharide, is a major component of non-lignified cell walls of dicotyledonous and some monocotyledonous plants. Its food-related technological functions are numerous and mirror many of its biological functions. As a naturally occurring component of raw or processed foods and a...

NON-REGULATED WATER CONTAMINANTS: EMERGING RESEARCH

EPA Science Inventory

Those chemical pollutants that are regulated under various international, federal, and state programs represent but a small fraction of the universe of chemicals that occur in the environment as a result of both natural processes and human influence. Although this galaxy of targe...

40 CFR 300.400 - General.

Code of Federal Regulations, 2010 CFR

2010-07-01

... unaltered form, or altered solely through naturally occurring processes or phenomena, from a location where... federal agency, and a state or political subdivision operating pursuant to a contract or cooperative... or political subdivision operating pursuant to a contract or cooperative agreement under CERCLA...

Mass fractionation processes of transition metal isotopes

NASA Astrophysics Data System (ADS)

Zhu, X. K.; Guo, Y.; Williams, R. J. P.; O'Nions, R. K.; Matthews, A.; Belshaw, N. S.; Canters, G. W.; de Waal, E. C.; Weser, U.; Burgess, B. K.; Salvato, B.

2002-06-01

Recent advances in mass spectrometry make it possible to utilise isotope variations of transition metals to address some important issues in solar system and biological sciences. Realisation of the potential offered by these new isotope systems however requires an adequate understanding of the factors controlling their isotope fractionation. Here we show the results of a broadly based study on copper and iron isotope fractionation during various inorganic and biological processes. These results demonstrate that: (1) naturally occurring inorganic processes can fractionate Fe isotope to a detectable level even at temperature ˜1000°C, which challenges the previous view that Fe isotope variations in natural system are unique biosignatures; (2) multiple-step equilibrium processes at low temperatures may cause large mass fractionation of transition metal isotopes even when the fractionation per single step is small; (3) oxidation-reduction is an importation controlling factor of isotope fractionation of transition metal elements with multiple valences, which opens a wide range of applications of these new isotope systems, ranging from metal-silicate fractionation in the solar system to uptake pathways of these elements in biological systems; (4) organisms incorporate lighter isotopes of transition metals preferentially, and transition metal isotope fractionation occurs stepwise along their pathways within biological systems during their uptake.

Vibrational Spectroscopy in Studies of Atmospheric Corrosion

PubMed Central

Hosseinpour, Saman; Johnson, Magnus

2017-01-01

Vibrational spectroscopy has been successfully used for decades in studies of the atmospheric corrosion processes, mainly to identify the nature of corrosion products but also to quantify their amounts. In this review article, a summary of the main achievements is presented with focus on how the techniques infrared spectroscopy, Raman spectroscopy, and vibrational sum frequency spectroscopy can be used in the field. Several different studies have been discussed where these instruments have been used to assess both the nature of corrosion products as well as the properties of corrosion inhibitors. Some of these techniques offer the valuable possibility to perform in-situ measurements in real time on ongoing corrosion processes, which allows the kinetics of formation of corrosion products to be studied, and also minimizes the risk of changing the surface properties which may occur during ex-situ experiments. Since corrosion processes often occur heterogeneously over a surface, it is of great importance to obtain a deeper knowledge about atmospheric corrosion phenomena on the nano scale, and this review also discusses novel vibrational microscopy techniques allowing spectra to be acquired with a spatial resolution of 20 nm. PMID:28772781

Reactive processing of textile-natural fiber reinforced anionic polyamide-6 composites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kan, Ze; Chen, Peng; Liu, Zhengying

Nowadays natural fiber, used in reinforced composites, is widely concerned. However, no natural fiber reinforced reactive thermoplastic polymer grades had been prepared so far. Through our studies, it was demonstrated that there was a severe retardation and discoloration occurred in the reactive processing between anionic polyamide-6 (APA-6) and natural fiber, which result in incomplete polymerization when put together. In order to solve the problem, two methods were adopted in this paper, which are fiber pretreatment and usage of a new-style initiator called caprolactam magnesium bromide. The former is to remove sizing agent and impurities on the surface of fiber, andmore » the latter is to weaken the side reactions between APA-6 and natural fiber by the nature of its lower reactivity and weaker alkaline. In cooperation with both methods, the severe retardation and discoloration had been improved significantly, so that the polymerization of APA-6 in natural fiber was occurred smoothly. Following textile-natural fiber reinforced APA-6 composites with an average thickness of 2.5 mm and a fiber volume content of 50% was prepared by vacuum assisted resin transfer molding (VARTM). The soxhlet extraction, dilute solution viscometry and differential scanning calorimeter (DSC) measurements respectively suggested the degree of conversion, viscosity-average molar mass and crystallization of composites was up to 94%, 11.3×104 and 50%. Remarkable improvement of mechanical properties were achieved through dynamic mechanical analysis (DMA), tensile and three-point bending test. Favorable interfacial adhesion and wettability were revealed by scanning electron microscopy (SEM) observation. Therefore, all of the above good performance make this new-style and environmentally friendly composites have broad application prospects.« less

Reactive processing of textile-natural fiber reinforced anionic polyamide-6 composites

NASA Astrophysics Data System (ADS)

Kan, Ze; Chen, Peng; Liu, Zhengying; Feng, Jianmin; Yang, Mingbo

2015-05-01

Nowadays natural fiber, used in reinforced composites, is widely concerned. However, no natural fiber reinforced reactive thermoplastic polymer grades had been prepared so far. Through our studies, it was demonstrated that there was a severe retardation and discoloration occurred in the reactive processing between anionic polyamide-6 (APA-6) and natural fiber, which result in incomplete polymerization when put together. In order to solve the problem, two methods were adopted in this paper, which are fiber pretreatment and usage of a new-style initiator called caprolactam magnesium bromide. The former is to remove sizing agent and impurities on the surface of fiber, and the latter is to weaken the side reactions between APA-6 and natural fiber by the nature of its lower reactivity and weaker alkaline. In cooperation with both methods, the severe retardation and discoloration had been improved significantly, so that the polymerization of APA-6 in natural fiber was occurred smoothly. Following textile-natural fiber reinforced APA-6 composites with an average thickness of 2.5 mm and a fiber volume content of 50% was prepared by vacuum assisted resin transfer molding (VARTM). The soxhlet extraction, dilute solution viscometry and differential scanning calorimeter (DSC) measurements respectively suggested the degree of conversion, viscosity-average molar mass and crystallization of composites was up to 94%, 11.3×104 and 50%. Remarkable improvement of mechanical properties were achieved through dynamic mechanical analysis (DMA), tensile and three-point bending test. Favorable interfacial adhesion and wettability were revealed by scanning electron microscopy (SEM) observation. Therefore, all of the above good performance make this new-style and environmentally friendly composites have broad application prospects.

Analytical group decision making in natural resources: Methodology and application

USGS Publications Warehouse

Schmoldt, D.L.; Peterson, D.L.

2000-01-01

Group decision making is becoming increasingly important in natural resource management and associated scientific applications, because multiple values are treated coincidentally in time and space, multiple resource specialists are needed, and multiple stakeholders must be included in the decision process. Decades of social science research on decision making in groups have provided insights into the impediments to effective group processes and on techniques that can be applied in a group context. Nevertheless, little integration and few applications of these results have occurred in resource management decision processes, where formal groups are integral, either directly or indirectly. A group decision-making methodology is introduced as an effective approach for temporary, formal groups (e.g., workshops). It combines the following three components: (1) brainstorming to generate ideas; (2) the analytic hierarchy process to produce judgments, manage conflict, enable consensus, and plan for implementation; and (3) a discussion template (straw document). Resulting numerical assessments of alternative decision priorities can be analyzed statistically to indicate where group member agreement occurs and where priority values are significantly different. An application of this group process to fire research program development in a workshop setting indicates that the process helps focus group deliberations; mitigates groupthink, nondecision, and social loafing pitfalls; encourages individual interaction; identifies irrational judgments; and provides a large amount of useful quantitative information about group preferences. This approach can help facilitate scientific assessments and other decision-making processes in resource management.

Integrating long-term stewardship goals into the remediation process: natural resource damages and the Department of Energy.

PubMed

Burger, Joanna; Gochfeld, Michael; Powers, Charles W

2007-01-01

The United States and other developed countries are faced with restoring and managing degraded ecosystems. Evaluations of the degradation of ecological resources can be used for determining ecological risk, making remediation or restoration decisions, aiding stakeholders with future land use decisions, and assessing natural resource damages. Department of Energy (DOE) lands provide a useful case study for examining degradation of ecological resources in light of past or present land uses and natural resource damage assessment (NRDA). We suggest that past site history should be incorporated into the cleanup and restoration phase to reduce the ultimate NRDA costs, and hasten resource recovery. The lands that DOE purchased over 50 years ago ranged from relatively undisturbed to heavily impacted farmland, and the impact that occurred from DOE occupation varies from regeneration of natural ecosystems (benefits) to increased exposure to several stressors (negative effects). During the time of the DOE releases, other changes occurred on the lands, including recovery from the disturbance effects of farming, grazing, and residential occupation, and the cessation of human disturbance. Thus, the injury to natural resources that occurred as a result of chemical and radiological releases occurred on top of recovery of already degraded systems. Both spatial (size and dispersion of patch types) and temporal (past/present/future land use and ecological condition) components are critical aspects of resource evaluation, restoration, and NRDA. For many DOE sites, integrating natural resource restoration with remediation to reduce or eliminate the need for NRDA could be a win-win situation for both responsible parties and natural resource trustees by eliminating costly NRDAs by both sides, and by restoring natural resources to a level that satisfies the trustees, while being cost-effective for the responsible parties. It requires integration of remediation, restoration, and end-state planning to a greater degree than is currently done at most DOE sites.

Chemistry of rubber processing and disposal.

PubMed Central

Bebb, R L

1976-01-01

The major chemical changes during the processing of rubber occur with the breakdown in mastication and during vulcanization of the molded tire. There is little chemical change during the compounding, calendering, extrusion, and molding steps. Reclaiming is the process of converting scrap rubber into an unsaturated, processible product that can be vulcanized with sulfur. Pyrolysis of scrap rubber yields a complex mixture of liquids, gas, and residue in varying ratios dependent on the nature of the scrap and the conditions of pyrolysis. PMID:799964

PHARMACEUTICALS AS UBIQUITOUS POLLUTANTS: SIGNIFICANCE, CONCERNS, SOLUTIONS

EPA Science Inventory

Those chemical pollutants that are regulated under various international, federal, and state programs represent but a small fraction of the universe of chemicals that occur in the environment as a result of both natural processes and human influence. Although this galaxy of targe...

40 CFR 436.380 - Applicability; description of the graphite subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... graphite subcategory. 436.380 Section 436.380 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Graphite Subcategory § 436.380 Applicability; description of the graphite subcategory. The provisions of this subpart are applicable to the mining and processing of naturally occurring graphite. ...

Folding of the natural hammerhead ribozyme is enhanced by interaction of auxiliary elements

PubMed Central

PENEDO, J. CARLOS; WILSON, TIMOTHY J.; JAYASENA, SUMEDHA D.; KHVOROVA, ANASTASIA; LILLEY, DAVID M.J.

2004-01-01

It has been shown that the activity of the hammerhead ribozyme at μM magnesium ion concentrations is markedly increased by the inclusion of loops in helices I and II. We have studied the effect of such loops on the magnesium ion-induced folding of the ribozyme, using fluorescence resonance energy transfer. We find that with the loops in place, folding into the active conformation occurs in a single step, in the μM range of magnesium ion concentration. Disruption of the loop–loop interaction leads to a reversion to two-step folding, with the second stage requiring mM concentrations of magnesium ion. Sodium ions also promote the folding of the natural form of the ribozyme at high concentrations, but the folding occurs as a two-stage process. The loops clearly act as important auxiliary elements in the function of the ribozyme, permitting folding to occur efficiently under physiological conditions. PMID:15100442

Occurrence and behavior of natural and anthropogenic (emerging and historical) halogenated compounds in marine biota from the Coast of Concepcion (Chile).

PubMed

Barón, Enrique; Rudolph, Ignacio; Chiang, Gustavo; Barra, Ricardo; Eljarrat, Ethel; Barceló, Damià

2013-09-01

Fifty-five biota samples from the Coast of Concepcion (Chile) were analyzed for PBDEs, emerging brominated FRs, halogenated norbornenes and naturally-occurring MeO-PBDEs. PBDEs, MeO-PBDEs and halogenated norbornenes were detected at concentration levels ranging from 11 to 170, nd to 118 and nd to 5.8 ng/g lw, respectively. However, emerging brominated FRs such as decabromodiphenylethane (DBDPE), hexabromobenzene (HBB) and pentabromoethylbenzene (PBEB) were not detected in any sample. Bioaccumulation and bioconcentration processes were evaluated for the different families of compounds. Biomagnification factors (BMFs) were calculated, and some PBDE congeners (BDE-28, BDE-183 and BDE-209) as well as MeO-PBDEs presented BMF>1, being values of the naturally occurring MeO-PBDEs higher than those obtained for PBDEs. As regards halogenated norbornenes, BMF<1 were found. Copyright © 2013 Elsevier B.V. All rights reserved.

Radiological protection in North American naturally occurring radioactive material industries.

PubMed

Chambers, D B

2015-06-01

All soils and rocks contain naturally occurring radioactive material (NORM). Many ores and raw materials contain relatively high levels of natural radionuclides, and processing such materials can further increase the concentrations of natural radionuclides, sometimes referred to as 'technologically enhanced naturally occurring radioactive material' (TENORM). Examples of NORM minerals include uranium ores, monazite (a source of rare earth minerals), and phosphate rock used to produce phosphate fertiliser. Such activities have the potential to result in above background radiation exposure to workers and the public. The objective of this paper is to review the sources and exposure from NORM in North American industries, and provide a perspective on the potential radiological hazards to workers and the environment. Proper consideration of NORM issues is important and needs to be integrated in the assessment of these projects. Concerns over radioactivity and radiation amongst non-governmental organisations and the local public have resulted in the cancellation of NORM mining and mineral extraction projects, as well as inhibition of the safe use of by-product materials from various NORM industries. This paper also briefly comments on the current regulatory framework for NORM (TENORM) in Canada and the USA, as well as the potential implications of the recent activities of the International Commission on Radiological Protection for NORM industries. © The International Society for Prosthetics and Orthotics Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

Multi-sensory learning and learning to read.

PubMed

Blomert, Leo; Froyen, Dries

2010-09-01

The basis of literacy acquisition in alphabetic orthographies is the learning of the associations between the letters and the corresponding speech sounds. In spite of this primacy in learning to read, there is only scarce knowledge on how this audiovisual integration process works and which mechanisms are involved. Recent electrophysiological studies of letter-speech sound processing have revealed that normally developing readers take years to automate these associations and dyslexic readers hardly exhibit automation of these associations. It is argued that the reason for this effortful learning may reside in the nature of the audiovisual process that is recruited for the integration of in principle arbitrarily linked elements. It is shown that letter-speech sound integration does not resemble the processes involved in the integration of natural audiovisual objects such as audiovisual speech. The automatic symmetrical recruitment of the assumedly uni-sensory visual and auditory cortices in audiovisual speech integration does not occur for letter and speech sound integration. It is also argued that letter-speech sound integration only partly resembles the integration of arbitrarily linked unfamiliar audiovisual objects. Letter-sound integration and artificial audiovisual objects share the necessity of a narrow time window for integration to occur. However, they differ from these artificial objects, because they constitute an integration of partly familiar elements which acquire meaning through the learning of an orthography. Although letter-speech sound pairs share similarities with audiovisual speech processing as well as with unfamiliar, arbitrary objects, it seems that letter-speech sound pairs develop into unique audiovisual objects that furthermore have to be processed in a unique way in order to enable fluent reading and thus very likely recruit other neurobiological learning mechanisms than the ones involved in learning natural or arbitrary unfamiliar audiovisual associations. Copyright 2010 Elsevier B.V. All rights reserved.

Construction aggregates

USGS Publications Warehouse

Nelson, T.I.; Bolen, W.P.

2007-01-01

Construction aggregates, primarily stone, sand and gravel, are recovered from widespread naturally occurring mineral deposits and processed for use primarily in the construction industry. They are mined, crushed, sorted by size and sold loose or combined with portland cement or asphaltic cement to make concrete products to build roads, houses, buildings, and other structures. Much smaller quantities are used in agriculture, cement manufacture, chemical and metallurgical processes, glass production and many other products.

The grief map

NASA Astrophysics Data System (ADS)

Monteiro, L. H. A.

2014-12-01

Grieving is a natural human reaction to a significant loss. According to a psychiatric model, this process is characterized by a typical sequence of psychological changes. Here, I propose a discrete-time dynamical system, called the grief map, in order to represent the grieving process. The corresponding bifurcation diagram, which exhibits stationary, periodic, and chaotic behavior, is related to the stages of this sorrowful journey occurring during about 12 months post-loss.

Process development for producing fine-grain casting in space

NASA Technical Reports Server (NTRS)

Gelles, S. H.; Malik, R. K.

1975-01-01

Assessment of grain growth kinetics at temperatures near the melting point and investigation into the use of potential nucleating agents in combination with the naturally occurring BeO led to the definition of critical low-g experiments which would help to determine whether one or both of these possibilities are valid and whether space processing would be able to yield fine grain ingot beryllium.

Enzyme technology for precision functional food ingredient processes.

PubMed

Meyer, Anne S

2010-03-01

A number of naturally occurring dietary substances may exert physiological benefits. The production of enhanced levels or particularly tailored versions of such candidate functional compounds can be targeted by enzymatic catalysis. The recent literature contains examples of enhancing bioavailability of iron via enzyme-catalyzed degradation of phytate in wheat bran, increasing diacyl-glycerol and conjugated linoleic acid levels by lipase action, enhancing the absorption of the citrus flavonoid hesperetin via rhamnosidase treatment, and obtaining solubilized dietary fiber via enzymatic modification of potato starch processing residues. Such targeted enzyme-catalyzed reactions provide new invention opportunities for designing functional foods with significant health benefits. The provision of well-defined naturally structured compounds can, moreover, assist in obtaining the much-needed improved understanding of the physiological benefits of complex natural substances.

Alaska, Naturally Occurring Asbestos: Experiences, Policy and 2012 Limitation of Liability Legislation

NASA Astrophysics Data System (ADS)

Hargesheimer, J.; Perkins, R.

2012-12-01

Naturally Occurring Asbestos (NOA) occurs in mineral deposits in Alaska. There are many regions in Alaska that have minerals in surface rocks that may contain asbestos and asbestos has been discovered in many locations in Alaska. Gravel is constantly in demand for heavy construction projects, but some remote localities in Alaska do not have gravel sources that are NOA-free. Determining if NOA can be safely used in heavy construction materials and what can or should be done with NOA materials that are already in place are complex questions. Answers will depend on the amount and type of asbestos mineral, how it is handled in processing, and how it is maintained - all subject to regulation and control of operations. The State of Alaska recently enacted legislation (HB 258) providing, among other things, "… immunity for the state and for landowners, extractors, suppliers, transporters, and contractors for certain actions or claims arising in connection with the use of gravel or aggregate material containing naturally occurring asbestos in certain areas." Implementation of the law and interim regulations and guidance should enable use of NOA for heavy construction materials in Alaska, but as with any new law, it will take some time to understand its full scope and effect.

An approach for estimating toxic releases of H2S-containing natural gas.

PubMed

Jianwen, Zhang; Da, Lei; Wenxing, Feng

2014-01-15

China is well known being rich in sulfurous natural gas with huge deposits widely distributed all over the country. Due to the toxic nature, the release of hydrogen sulfide-containing natural gas from the pipelines intends to impose serious threats to the human, society and environment around the release sources. CFD algorithm is adopted to simulate the dispersion process of gas, and the results prove that Gaussian plume model is suitable for determining the affected region of the well blowout of sulfide hydrogen-containing natural gas. In accordance with the analysis of release scenarios, the present study proposes a new approach for estimating the risk of hydrogen sulfide poisoning hazards, as caused by sulfide-hydrogen-containing natural gas releases. Historical accident-statistical data from the EGIG (European Gas Pipeline Incident Data Group) and the Britain Gas Transco are integrated into the approach. Also, the dose-load effect is introduced to exploit the hazards' effects by two essential parameters - toxic concentration and exposure time. The approach was applied to three release scenarios occurring on the East-Sichuan Gas Transportation Project, and the individual risk and societal risk are classified and discussed. Results show that societal risk varies significantly with different factors, including population density, distance from pipeline, operating conditions and so on. Concerning the dispersion process of hazardous gas, available safe egress time was studied from the perspective of individual fatality risks. The present approach can provide reliable support for the safety management and maintenance of natural gas pipelines as well as evacuations that may occur after release incidents. Copyright © 2013 Elsevier B.V. All rights reserved.

Micro-organisms in latex and natural rubber coagula of Hevea brasiliensis and their impact on rubber composition, structure and properties.

PubMed

Salomez, M; Subileau, M; Intapun, J; Bonfils, F; Sainte-Beuve, J; Vaysse, L; Dubreucq, E

2014-10-01

Natural rubber, produced by coagulation of the latex from the tree Hevea brasiliensis, is an important biopolymer used in many applications for its outstanding properties. Besides polyisoprene, latex is rich in many nonisoprene components such as carbohydrates, proteins and lipids and thereby constitutes a favourable medium for the development of micro-organisms. The fresh rubber coagula obtained by latex coagulation are not immediately processed, allowing the development of various microbial communities. The time period between tree tapping and coagula processing is called maturation, during which an evolution of the properties of the corresponding dry natural rubber occurs. This evolution is partly related to the activity of micro-organisms and to the modification of the biochemical composition. This review synthesizes the current knowledge on microbial populations in latex and natural rubber coagula of H. brasiliensis and the changes they induce on the biochemistry and technical properties of natural rubber during maturation. © 2014 The Society for Applied Microbiology.

Extending topological surgery to natural processes and dynamical systems.

PubMed

Antoniou, Stathis; Lambropoulou, Sofia

2017-01-01

Topological surgery is a mathematical technique used for creating new manifolds out of known ones. We observe that it occurs in natural phenomena where a sphere of dimension 0 or 1 is selected, forces are applied and the manifold in which they occur changes type. For example, 1-dimensional surgery happens during chromosomal crossover, DNA recombination and when cosmic magnetic lines reconnect, while 2-dimensional surgery happens in the formation of tornadoes, in the phenomenon of Falaco solitons, in drop coalescence and in the cell mitosis. Inspired by such phenomena, we introduce new theoretical concepts which enhance topological surgery with the observed forces and dynamics. To do this, we first extend the formal definition to a continuous process caused by local forces. Next, for modeling phenomena which do not happen on arcs or surfaces but are 2-dimensional or 3-dimensional, we fill in the interior space by defining the notion of solid topological surgery. We further introduce the notion of embedded surgery in S3 for modeling phenomena which involve more intrinsically the ambient space, such as the appearance of knotting in DNA and phenomena where the causes and effect of the process lies beyond the initial manifold, such as the formation of black holes. Finally, we connect these new theoretical concepts with a dynamical system and we present it as a model for both 2-dimensional 0-surgery and natural phenomena exhibiting a 'hole drilling' behavior. We hope that through this study, topology and dynamics of many natural phenomena, as well as topological surgery itself, will be better understood.

Extending topological surgery to natural processes and dynamical systems

PubMed Central

Antoniou, Stathis; Lambropoulou, Sofia

2017-01-01

Topological surgery is a mathematical technique used for creating new manifolds out of known ones. We observe that it occurs in natural phenomena where a sphere of dimension 0 or 1 is selected, forces are applied and the manifold in which they occur changes type. For example, 1-dimensional surgery happens during chromosomal crossover, DNA recombination and when cosmic magnetic lines reconnect, while 2-dimensional surgery happens in the formation of tornadoes, in the phenomenon of Falaco solitons, in drop coalescence and in the cell mitosis. Inspired by such phenomena, we introduce new theoretical concepts which enhance topological surgery with the observed forces and dynamics. To do this, we first extend the formal definition to a continuous process caused by local forces. Next, for modeling phenomena which do not happen on arcs or surfaces but are 2-dimensional or 3-dimensional, we fill in the interior space by defining the notion of solid topological surgery. We further introduce the notion of embedded surgery in S3 for modeling phenomena which involve more intrinsically the ambient space, such as the appearance of knotting in DNA and phenomena where the causes and effect of the process lies beyond the initial manifold, such as the formation of black holes. Finally, we connect these new theoretical concepts with a dynamical system and we present it as a model for both 2-dimensional 0-surgery and natural phenomena exhibiting a ‘hole drilling’ behavior. We hope that through this study, topology and dynamics of many natural phenomena, as well as topological surgery itself, will be better understood. PMID:28915271

Inhibition and kinetic studies of lignin degrading enzymes of Ganoderma boninense by naturally occurring phenolic compounds.

PubMed

Surendran, Arthy; Siddiqui, Yasmeen; Saud, Halimi Mohd; Ali, Nusaibah Syd; Manickam, Sivakumar

2018-05-22

Lignolytic (Lignin degrading) enzyme, from oil palm pathogen Ganoderma boninense Pat. (Syn G. orbiforme (Ryvarden), is involved in the detoxification and the degradation of lignin in the oil palm and is the rate-limiting step in the infection process of this fungus. Active inhibition of lignin degrading enzymes secreted by G. boninense by various naturally occurring phenolic compounds and estimation of efficiency on pathogen suppression was aimed at. In our work, ten naturally occurring phenolic compounds were evaluated for their inhibitory potential towards the lignolytic enzymes of G.boninense. Additionally, the lignin degrading enzymes were characterised. Most of the peholic compounds exhibited an uncompetitive inhibition towards the lignin degrading enzymes. Benzoic acid was the superior inhibitor to the production of lignin degrading enzymes, when compared between the ten phenolic compounds. The inhibitory potential of the phenolic compounds toward the lignin degrading enzymes are higher than that of the conventional metal ion inhibitor. The lignin degrading enzymes were stable in a wide range of pH but were sensitive to higher to temperature. The study demonstrated the inhibitor potential of ten naturally occurring phenolic compounds toward the lignin degrading enzymes of G. boninense with different efficacies. The study has shed a light towards a new management strategy to control BSR in oil palm. It serves as replacement for the existing chemical control. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

California Dept. of Toxic Substances Control (DTSC) Update of the Schools Naturally Occurring Asbestos Guidance

NASA Astrophysics Data System (ADS)

Malinowski, M.

2012-12-01

Prior to acquisition and/or construction of prospective school sites, the California Education Code mandates that school districts complete environmental assessments and cleanups for prospective new or expanding school sites in order to qualify for state funding. If prospective school sites are determined to have environmental contamination from hazardous materials, including naturally occurring hazardous materials such as naturally occurring asbestos (NOA), where there may be unacceptable potential health risks, the school sites must be properly mitigated prior to occupancy for protection of human health and the environment. NOA is of special concern for schools, because children who are exposed to asbestos may be at increased risk of developing asbestos-related diseases over time. In order to protect human health, the Department of Toxic Substances Control's (DTSC) goals at school sites are to: 1) identify the presence of NOA in school site soils using exposure-reducing soil thresholds; 2) manage potential NOA exposures using mitigation measures to reduce generation of airborne asbestos fibers from soils on school sites; and 3) ensure long-term monitoring and protection of mitigation measures via Operations & Maintenance activities. DTSC is currently in the process of revising its Interim Guidance Naturally Occurring Asbestos (NOA) at School Sites - September 2004. The revisions include: 1) updating the guidance to consider incremental sampling for use at NOA sites in consultation with DTSC's project manager and technical staff, and 2) documenting a tiered approach to addressing high and low activity areas on a school.

Naturally occurring radioactive materials (NORM): a matter of wide societal implication.

PubMed

Pescatore, C; Menon, S

2000-12-01

Naturally occurring radioactive materials are ubiquitous on Earth and their radioactivity may become concentrated as a result of human activities. Numerous industries produce concentrated radioactivity in their by-products: the coal industry, petroleum extraction and processing, water treatment, etc. The present reference system of radiation protection does not provide a complete framework for the coherent management of all types of radioactively contaminated materials. Inconsistencies in waste management policy and practice can be noted across the board, and especially vis-à-vis the management of radioactive waste from the nuclear industry. This article reviews the present societal approach to manage materials that are radioactive but are often not recognised as being such, and place the management of radioactive materials from the nuclear industry in perspective.

Novel method of extracting motion from natural movies.

PubMed

Suzuki, Wataru; Ichinohe, Noritaka; Tani, Toshiki; Hayami, Taku; Miyakawa, Naohisa; Watanabe, Satoshi; Takeichi, Hiroshige

2017-11-01

The visual system in primates can be segregated into motion and shape pathways. Interaction occurs at multiple stages along these pathways. Processing of shape-from-motion and biological motion is considered to be a higher-order integration process involving motion and shape information. However, relatively limited types of stimuli have been used in previous studies on these integration processes. We propose a new algorithm to extract object motion information from natural movies and to move random dots in accordance with the information. The object motion information is extracted by estimating the dynamics of local normal vectors of the image intensity projected onto the x-y plane of the movie. An electrophysiological experiment on two adult common marmoset monkeys (Callithrix jacchus) showed that the natural and random dot movies generated with this new algorithm yielded comparable neural responses in the middle temporal visual area. In principle, this algorithm provided random dot motion stimuli containing shape information for arbitrary natural movies. This new method is expected to expand the neurophysiological and psychophysical experimental protocols to elucidate the integration processing of motion and shape information in biological systems. The novel algorithm proposed here was effective in extracting object motion information from natural movies and provided new motion stimuli to investigate higher-order motion information processing. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

Geochemistry of the Amazon Estuary

USGS Publications Warehouse

Smoak, Joseph M.; Krest, James M.; Swarzenski, Peter W

2006-01-01

The Amazon River supplies more freshwater to the ocean than any other river in the world. This enormous volume of freshwater forces the estuarine mixing out of the river channel and onto the continental shelf. On the continental shelf, the estuarine mixing occurs in a very dynamic environment unlike that of a typical estuary. The tides, the wind, and the boundary current that sweeps the continental shelf have a pronounced influence on the chemical and biological processes occurring within the estuary. The dynamic environment, along with the enormous supply of water, solutes and particles makes the Amazon estuary unique. This chapter describes the unique features of the Amazon estuary and how these features influence the processes occurring within the estuary. Examined are the supply and cycling of major and minor elements, and the use of naturally occurring radionuclides to trace processes including water movement, scavenging, sediment-water interaction, and sediment accumulation rates. The biogeochemical cycling of carbon, nitrogen, and phosphorus, and the significances of the Amazon estuary in the global mass balance of these elements are examined.

Recovery from cannabis use disorders: Abstinence versus moderation and treatment-assisted recovery versus natural recovery.

PubMed

Stea, Jonathan N; Yakovenko, Igor; Hodgins, David C

2015-09-01

The present study of recovery from cannabis use disorders was undertaken with 2 primary objectives that address gaps in the literature. The first objective was to provide an exploratory portrait of the recovery process from cannabis use disorders, comparing individuals who recovered naturally with those who were involved in treatment. The second objective was to explore systematically the similarities and differences between abstinence and moderation recoveries. Adults who have recovered from a cannabis use disorder were recruited in the community (N = 119). The abstinence and treatment-assisted participants exhibited higher levels of lifetime cannabis problem severity than the moderation and natural recovery participants, respectively. As well, cognitive factors were identified as the most useful strategies for recovery (e.g., thinking about benefits and negative consequences of cannabis), followed by behavioral factors (e.g., avoidance of triggers for use and high-risk situations). Findings lend further support to the effectiveness of cognitive, motivational, and behavioral strategies as helpful actions and maintenance factors involved in the recovery process. The findings also generally support the idea that cannabis use disorders lie on a continuum of problem severity, with moderation and natural recoveries more likely to occur at the lower end of the continuum and abstinence and treatment-assisted recoveries more likely to occur at the upper end. (c) 2015 APA, all rights reserved).

The "emotion misattribution" procedure: processing beyond good and bad under masked and unmasked presentation conditions.

PubMed

Rohr, Michaela; Degner, Juliane; Wentura, Dirk

2015-01-01

In general, it is assumed that misattribution in the Affect Misattribution Procedure (AMP) is restricted to crude affect due to its unbound nature, especially under limited presentation conditions. In two experiments, we investigated whether emotion-specific misattributions occur using a four-category misattribution procedure. Experiment 1 yielded emotion-specific misattribution effects under clearly visible presentation conditions demonstrating that the procedure is principally susceptible for emotion-specific effects. In Experiment 2, we employed masked presentation conditions impeding conscious prime perception. A specific pattern of emotion-specific misattributions effects emerged indicating some emotion-specific processing at initial stages of processing. However, not each emotion was misattributed equally. We discuss the implications of these results for the non-conscious processing of emotional information, for the supposed mechanisms of the AMP and its implicit nature.

Carbonate Precipitation through Microbial Activities in Natural Environment, and Their Potential in Biotechnology: A Review

PubMed Central

Zhu, Tingting; Dittrich, Maria

2016-01-01

Calcium carbonate represents a large portion of carbon reservoir and is used commercially for a variety of applications. Microbial carbonate precipitation, a by-product of microbial activities, plays an important metal coprecipitation and cementation role in natural systems. This natural process occurring in various geological settings can be mimicked and used for a number of biotechnologies, such as metal remediation, carbon sequestration, enhanced oil recovery, and construction restoration. In this study, different metabolic activities leading to calcium carbonate precipitation, their native environment, and potential applications and challenges are reviewed. PMID:26835451

Multi-scale wind erosion monitoring and assessment for US rangelands

USDA-ARS?s Scientific Manuscript database

Wind erosion is a major resource concern for rangeland managers. Although wind erosion is a naturally occurring process in many drylands, land use activities, and land management in particular, can accelerate wind-driven soil loss – impacting ecosystem dynamics and agricultural production, air quali...

Development of biodegradable foamlike materials based on casein and sodium montmorillonite clay

USDA-ARS?s Scientific Manuscript database

Biodegradable foamlike materials based on a naturally occurring polymer (casein protein) and sodium montmorillonite clay (Na+-MMT) were produced through a simple freeze-drying process. By utilizing DL-glyceraldehyde (GC) as a chemical cross-linking agent, the structural integrity of these new aeroge...

Single Particle ICPMS for Characterizing Metal-based Nanoparticles and Monitoring Transformation Processes in Surface Water

EPA Science Inventory

Engineered metal-based nanomaterials will likely be used in increasing quantities in consumer and industrial products. These may be introduced into surface waters by a variety of paths depending on usage. Other naturally occurring and anthropogenic particles containing these met...

Impact of Natural (Storm) and Anthropogenic (Trawl) Resuspension the Sediment Transport on the Gulf of Lion's Shelf (NW Mediterranean)

NASA Astrophysics Data System (ADS)

Ferre, B.; Durrieu de Madron, X.; Estournel, C.; Ulses, C.; Le Corre, G.

2006-12-01

Modern sediment deposits on continental margins form a vast reservoir of particulate matter that is regularly affected by resuspension processes. On shelves with strong fishing activity, resuspension by bottom trawling processes can modify the scale of natural disturbance by waves and currents. Recent field data shows that the impact of bottom trawls on the resuspension of the fine sediments per unit surface is comparable with that of the largest storms. We assessed the impact of both natural and anthropogenic processes on the dispersal of river-borne particles and shelf sediments on the Gulf of Lion's Shelf. Realistic numerical simulations of resuspension and transport forced by currents and waves or by a fleet of bottom trawlers were developed. Simulations were conducted for a 16-month period to characterize the seasonal variability. The sediment dynamics takes into account bed armoring, ripple geometry and the cohesive and non-cohesive characteristics of the sediment. Essential but uncertain parameters (clay content, erosion fluxes and critical shear stress for cohesive sediment) were set with existing data. Resuspension by waves and currents is controlled by the shear stress, whereas resuspension by the bottom trawler fleet is controlled by its density and distribution. Natural resuspension by waves and currents mostly occurs during short winter episodes, and is concentrated on the inner-shelf. Trawling-induced resuspension, in contrast, occurs regularly throughout the year and is concentrated on the outer shelf. The total annual net resuspension by trawls (8×106 T y-1 is four orders of magnitude lower than the resuspension induced by waves and currents (4×1010 T y-1. However, because trawled regions are located on the outer shelf, closer to the continental slope, export of fine sediment resuspended by trawls (0.6×106 T y-1 is only one order of magnitude lower than export associated with natural resuspension (8×106 T y-1. A simulation combining both resuspension processes reveals a decrease of about 10% in resuspension and export rates, compared with the sum of each individual process.

Natural analogues of nuclear waste glass corrosion.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Abrajano, T.A. Jr.; Ebert, W.L.; Luo, J.S.

1999-01-06

This report reviews and summarizes studies performed to characterize the products and processes involved in the corrosion of natural glasses. Studies are also reviewed and evaluated on how well the corrosion of natural glasses in natural environments serves as an analogue for the corrosion of high-level radioactive waste glasses in an engineered geologic disposal system. A wide range of natural and experimental corrosion studies has been performed on three major groups of natural glasses: tektite, obsidian, and basalt. Studies of the corrosion of natural glass attempt to characterize both the nature of alteration products and the reaction kinetics. Information availablemore » on natural glass was then compared to corresponding information on the corrosion of nuclear waste glasses, specifically to resolve two key questions: (1) whether one or more natural glasses behave similarly to nuclear waste glasses in laboratory tests, and (2) how these similarities can be used to support projections of the long-term corrosion of nuclear waste glasses. The corrosion behavior of basaltic glasses was most similar to that of nuclear waste glasses, but the corrosion of tektite and obsidian glasses involves certain processes that also occur during the corrosion of nuclear waste glasses. The reactions and processes that control basalt glass dissolution are similar to those that are important in nuclear waste glass dissolution. The key reaction of the overall corrosion mechanism is network hydrolysis, which eventually breaks down the glass network structure that remains after the initial ion-exchange and diffusion processes. This review also highlights some unresolved issues related to the application of an analogue approach to predicting long-term behavior of nuclear waste glass corrosion, such as discrepancies between experimental and field-based estimates of kinetic parameters for basaltic glasses.« less

Characterization of Explosives Processing Waste Decomposition Due to Composting

DTIC Science & Technology

1991-11-01

volume % of soil in the compost. The amendment mixture was 30% sawdust, 15% apple pomace, 20% chicken manure, and 35% chopped potato waste. The negative...experiments. 3.3 Dkictiion Naturally occurring soil- and sediment-dwelling microbes produce a diverse array of exo- and endoenzymes that can degrade...consortia of microbes . Additionally, the loss of TNT by microbial processes was accompanied by commensurate reductions in compost leachate toxicity and

Parasite effects on isopod feeding rates can alter the host's functional role in a natural stream ecosystem.

PubMed

Hernandez, Alexander D; Sukhdeo, Michael V K

2008-05-01

Changes to host behaviour as a consequence of infection are common in many parasite-host associations, but their effects on the functional role hosts play within ecosystems are rarely quantified. This study reports that helminth parasites significantly decrease consumption of detritus by their isopod hosts in laboratory experiments. Natural host and parasite densities across eight contiguous seasons were used to estimate effects on the amount of stream detritus-energy processed. Extrapolations using mass-specific processing rates from laboratory results to field patterns suggest that the effects of the parasites occur year round but the greatest impact on the amount of detritus processed by isopods occurs in the autumn when the bulk of leaf detritus enters the stream, and when parasite prevalence in the isopod population is high. Parasites have a lesser impact on the amount of detritus processed in spring and summer when isopods are most abundant, when parasite prevalence is not high, and when fish predation on isopods is high. These results support the idea that parasites can affect the availability of resources critical to other species by altering behaviours related to the functional role hosts play in ecosystems, and suggest that seasonality may be an important factor to consider in the dynamics of these parasite-host interactions.

Process For The Preparation Of 3,4-Dihyd Roxybutanoic Acid And Salts Thereof

DOEpatents

Hollingsworth, Rawle I.

1994-06-07

A process for the preparation of 3,4-dihydroxybutanoic acid (1) and salts thereof from a glucose source containing 1,4-linked glucose as a substituent is described. The process uses an alkali metal hdyroxide and hydrogen peroxide to convert the glucose source to (1). The compound (1) is useful as a chemical intermediate to naturally occurring fatty acids and is used to prepare 3,4-dihydroxybutanoic acid-gamma-lactone (2) and furanone (3), particularly stereoisomers of these compounds.

Process for the preparation of 3,4-dihydroxybutanoic acid and salts thereof

DOEpatents

Hollingsworth, Rawle I.

1994-01-01

A process for the preparation of 3,4-dihydroxybutanoic acid (1) and salts thereof from a glucose source containing 1,4-linked glucose as a substituent is described. The process uses an alkali metal hdyroxide and hydrogen peroxide to convert the glucose source to (1). The compound (1) is useful as a chemical intermediate to naturally occurring fatty acids and is used to prepare 3,4-dihydroxybutanoic acid-gamma-lactone (2) and furanone (3), particularly stereoisomers of these compounds.

Process for the preparation of 3,4-dihydroxybutanoic acid and salts thereof

DOEpatents

Hollingsworth, Rawle I.

1994-01-01

A process for the preparation of 3,4-dihydroxybutanoic acid (1) and salts thereof from a glucose source containing 1,4-1inked glucose as a substituent is described. The process uses an alkali metal hdyroxide and hydrogen peroxide to convert the glucose source to (1). The compound (1) is useful as a chemical intermediate to naturally occurring fatty acids and is used to prepare 3,4-dihydroxybutanoic acid-gamma-lactone (2) and furanone (3), particularly stereoisomers of these compounds.

Healing of a mechano-responsive material

NASA Astrophysics Data System (ADS)

Vetter, A.; Sander, O.; Duda, G. N.; Weinkamer, R.

2013-12-01

While contribution of physics to model fracture of materials is significant, the “reversed” process of healing is hardly investigated. Inspired by fracture healing that occurs as a self-repair process in nature, e.g. in bone, we computationally study the conditions under which a material can repair itself. In our model the material around a fracture is assumed mechano-responsive: it processes the information of i) local stiffness and ii) local strain and responds by local stiffening. Depending on how information i) and ii) is processed, healing evolves via fundamentally different paths.

Assessing Daily Stress Processes in Social Surveys by Combining Stressor Exposure and Salivary Cortisol

PubMed Central

Almeida, David M.; McGonagle, Katherine; King, Heather

2010-01-01

This paper presents a research method for assessing stress and mental health in ongoing population-based social surveys that combines self-reports of naturally occurring daily stressors with a primary marker of stress physiology, salivary cortisol. We first discuss the relevance of stress processes to mental health and introduce a model for examining daily stress processes, which highlights multiple components of daily stressor exposure. A primary aim of this approach is to capture variability across stressful situations, between persons of different groups, or within persons over a period of time. Next, we describe how the assessment of diurnal salivary cortisol is a promising approach to examining naturally occurring stress physiology in large social surveys. We then present findings from the National Study of Daily Experiences (a substudy of the Midlife in the United States Study) that document the feasibility and reliability of the collection of daily stressors and salivary diurnal cortisol and provide examples of research findings linking stressor exposure to diurnal cortisol. The final portion of the paper describes ways that this approach can leverage the strengths of various features of longitudinal social surveys to extend research on stress and mental health. PMID:20183906

The recharge process in alluvial strip aquifers in arid Namibia and implication for artificial recharge

NASA Astrophysics Data System (ADS)

Sarma, Diganta; Xu, Yongxin

2017-01-01

Alluvial strip aquifers associated with ephemeral rivers are important groundwater supply sources that sustain numerous settlements and ecological systems in arid Namibia. More than 70 % of the population in the nation's western and southern regions depend on alluvial aquifers associated with ephemeral rivers. Under natural conditions, recharge occurs through infiltration during flood events. Due to the characteristic spatial and temporal variability of rainfall in arid regions, recharge is irregular making the aquifers challenging to manage sustainably and they are often overexploited. This condition is likely to become more acute with increasing water demand and climate change, and artificial recharge has been projected as the apparent means of increasing reliability of supply. The article explores, through a case study and numerical simulation, the processes controlling infiltration, significance of surface water and groundwater losses, and possible artificial recharge options. It is concluded that recharge processes in arid alluvial aquifers differ significantly from those processes in subhumid systems and viability of artificial recharge requires assessment through an understanding of the natural recharge process and losses from the aquifer. It is also established that in arid-region catchments, infiltration through the streambed occurs at rates dependent on factors such as antecedent conditions, flow rate, flow duration, channel morphology, and sediment texture and composition. The study provides an important reference for sustainable management of alluvial aquifer systems in similar regions.

Radioactivity in fossils at the Hagerman Fossil Beds National Monument.

PubMed

Farmer, C Neal; Kathren, Ronald L; Christensen, Craig

2008-08-01

Since 1996, higher than background levels of naturally occurring radioactivity have been documented in both fossil and mineral deposits at Hagerman Fossil Beds National Monument in south-central Idaho. Radioactive fossil sites occur primarily within an elevation zone of 900-1000 m above sea level and are most commonly found associated with ancient river channels filled with sand. Fossils found in clay rich deposits do not exhibit discernable levels of radioactivity. Out of 300 randomly selected fossils, approximately three-fourths exhibit detectable levels of natural radioactivity ranging from 1 to 2 orders of magnitude above ambient background levels when surveyed with a portable hand held Geiger-Muller survey instrument. Mineral deposits in geologic strata also show above ambient background levels of radioactivity. Radiochemical lab analysis has documented the presence of numerous natural radioactive isotopes. It is postulated that ancient groundwater transported radioactive elements through sand bodies containing fossils which precipitated out of solution during the fossilization process. The elevated levels of natural radioactivity in fossils may require special precautions to ensure that exposures to personnel from stored or displayed items are kept as low as reasonably achievable (ALARA).

Network Centric Warfare: A Realistic Defense Alternative for Smaller Nations?

DTIC Science & Technology

2004-06-01

organic information sources. The degree to which force entities are networked will determine the quality of information that is available to various...control processes will determine the extent that information is shared, as well as the nature and quality of the interactions that occur between and...

Reading Coaching Discourse: Exploring Coaching Processes

ERIC Educational Resources Information Center

Heineke, Sally Frances

2009-01-01

This study investigates the discourse of elementary school reading coaches and teachers during coaching interactions in four Alabama schools. Coach/teacher dyads recorded naturally occurring coaching dialogue over periods of 3 to 6 weeks. Each participant shared her views on coaching and commented on the recorded discourse during post-interviews…

Knowledge Generated by Audiovisual Narrative Action Research Loops

ERIC Educational Resources Information Center

Bautista Garcia-Vera, Antonio

2012-01-01

We present data collected from the research project funded by the Ministry of Education and Science of Spain entitled "Audiovisual Narratives and Intercultural Relations in Education." One of the aims of the research was to determine the nature of thought processes occurring during audiovisual narratives. We studied the possibility of…

Management of Student Aid.

ERIC Educational Resources Information Center

Nevin, Jeanne, Ed.

The principles, practices, responsibilities, and controls in student financial aid are described in this manual. It traces the flow of funds, management activities, and legal issues as they occur in the process. The emphasis is on sound management principles of a general and permanent nature rather than on specific government requirements that may…

Sequential use of simulation and optimization in analysis and planning

Treesearch

Hans R. Zuuring; Jimmie D. Chew; J. Greg Jones

2000-01-01

Management activities are analyzed at landscape scales employing both simulation and optimization. SIMPPLLE, a stochastic simulation modeling system, is initially applied to assess the risks associated with a specific natural process occurring on the current landscape without management treatments, but with fire suppression. These simulation results are input into...

Examining the fate and transport of alpha- and beta-endosulfan in the atmosphere of South Florida

USDA-ARS?s Scientific Manuscript database

Agricultural activity in the South Florida region occurs in close proximity to both important natural areas like Biscayne and Everglades National Parks. One possible transport mechanism for pesticides into these sensitive ecosystems is release to the atmosphere after application. The process is en...

Student Teachers' Indirect Complaining in Learning Groups

ERIC Educational Resources Information Center

Pakkanen, Marjatta

2011-01-01

This article focuses on indirect complaining in teacher education. The phenomenon of complaining in educational situations has not been examined as a process before. In this study complaining was examined in naturally occurring learning group sessions, which were videotaped and analysed through Conversation Analysis (CA). The purpose of this study…

Lead-210 and polonium-210 in biological samples from Alaska.

PubMed

Beasley, T M; Palmer, H E

1966-05-20

The naturally occurring concentrations of lead-210 and polonium-210 in certain biological samples from Alaska are unusually high. The concentration processes are similar to those observed for artificially produced radioactive fallout. Concentrations of these nuclides are greater in Alaskan natives than they are in other United States residents.

Do Different Training Conditions Facilitate Team Implementation? A Quasi-Experimental Mixed Methods Study

ERIC Educational Resources Information Center

Nielsen, Karina; Randall, Raymond; Christensen, Karl B.

2017-01-01

A mixed methods approach was applied to examine the effects of a naturally occurring teamwork intervention supported with training. The first objective was to integrate qualitative process evaluation and quantitative effect evaluation to examine "how" and "why" the training influence intervention outcomes. The intervention (N =…

Talent Identification in Track and Field.

ERIC Educational Resources Information Center

Henson, Phillip; And Others

Talent identification in most sports occurs through mass participation and the process of natural selection; track and field does not enjoy such widespread participation. This paper reports on a project undertaken for the following purposes: improve the means by which youth with the potential for high level performance can be identified; develop…

Archaeomagnetic Dating

ERIC Educational Resources Information Center

Linford, Paul

2004-01-01

Some naturally occurring minerals possess a permanent magnetization. Certain processes such as sedimentation or kiln-firing can cause the particles in structures made of such materials to align themselves with the direction of Earth's magnetic field at the time. This direction has varied over the last few thousand years in ways that can be traced…

Naturally Occurring Human Urinary Peptides for Use in Diagnosis of Chronic Kidney Disease*

PubMed Central

Good, David M.; Zürbig, Petra; Argilés, Àngel; Bauer, Hartwig W.; Behrens, Georg; Coon, Joshua J.; Dakna, Mohammed; Decramer, Stéphane; Delles, Christian; Dominiczak, Anna F.; Ehrich, Jochen H. H.; Eitner, Frank; Fliser, Danilo; Frommberger, Moritz; Ganser, Arnold; Girolami, Mark A.; Golovko, Igor; Gwinner, Wilfried; Haubitz, Marion; Herget-Rosenthal, Stefan; Jankowski, Joachim; Jahn, Holger; Jerums, George; Julian, Bruce A.; Kellmann, Markus; Kliem, Volker; Kolch, Walter; Krolewski, Andrzej S.; Luppi, Mario; Massy, Ziad; Melter, Michael; Neusüss, Christian; Novak, Jan; Peter, Karlheinz; Rossing, Kasper; Rupprecht, Harald; Schanstra, Joost P.; Schiffer, Eric; Stolzenburg, Jens-Uwe; Tarnow, Lise; Theodorescu, Dan; Thongboonkerd, Visith; Vanholder, Raymond; Weissinger, Eva M.; Mischak, Harald; Schmitt-Kopplin, Philippe

2010-01-01

Because of its availability, ease of collection, and correlation with physiology and pathology, urine is an attractive source for clinical proteomics/peptidomics. However, the lack of comparable data sets from large cohorts has greatly hindered the development of clinical proteomics. Here, we report the establishment of a reproducible, high resolution method for peptidome analysis of naturally occurring human urinary peptides and proteins, ranging from 800 to 17,000 Da, using samples from 3,600 individuals analyzed by capillary electrophoresis coupled to MS. All processed data were deposited in an Structured Query Language (SQL) database. This database currently contains 5,010 relevant unique urinary peptides that serve as a pool of potential classifiers for diagnosis and monitoring of various diseases. As an example, by using this source of information, we were able to define urinary peptide biomarkers for chronic kidney diseases, allowing diagnosis of these diseases with high accuracy. Application of the chronic kidney disease-specific biomarker set to an independent test cohort in the subsequent replication phase resulted in 85.5% sensitivity and 100% specificity. These results indicate the potential usefulness of capillary electrophoresis coupled to MS for clinical applications in the analysis of naturally occurring urinary peptides. PMID:20616184

Thermal resistance of naturally occurring airborne bacterial spores. [Viking spacecraft dry heat decontamination simulation

NASA Technical Reports Server (NTRS)

Puleo, J. R.; Bergstrom, S. L.; Peeler, J. T.; Oxborrow, G. S.

1978-01-01

Simulation of a heat process used in the terminal dry-heat decontamination of the Viking spacecraft is reported. Naturally occurring airborne bacterial spores were collected on Teflon ribbons in selected spacecraft assembly areas and subsequently subjected to dry heat. Thermal inactivation experiments were conducted at 105, 111.7, 120, 125, 130, and 135 C with a moisture level of 1.2 mg of water per liter. Heat survivors were recovered at temperatures of 135 C when a 30-h heating cycle was employed. Survivors were recovered from all cycles studied and randomly selected for identification. The naturally occurring spore population was reduced an average of 2.2 to 4.4 log cycles from 105 to 135 C. Heating cycles of 5 and 15 h at temperature were compared with the standard 30-h cycle at 111.7, 120, and 125 C. No significant differences in inactivation (alpha = 0.05) were observed between 111.7 and 120 C. The 30-h cycle differs from the 5- and 15-h cycles at 125 C. Thus, the heating cycle can be reduced if a small fraction (about 0.001 to 0.0001) of very resistant spores can be tolerated.

Stochastic phase segregation on surfaces

PubMed Central

Gera, Prerna

2017-01-01

Phase separation and coarsening is a phenomenon commonly seen in binary physical and chemical systems that occur in nature. Often, thermal fluctuations, modelled as stochastic noise, are present in the system and the phase segregation process occurs on a surface. In this work, the segregation process is modelled via the Cahn–Hilliard–Cook model, which is a fourth-order parabolic stochastic system. Coarsening is analysed on two sample surfaces: a unit sphere and a dumbbell. On both surfaces, a statistical analysis of the growth rate is performed, and the influence of noise level and mobility is also investigated. For the spherical interface, it is also shown that a lognormal distribution fits the growth rate well. PMID:28878994

Coupling mRNA processing with transcription in time and space

PubMed Central

Bentley, David L.

2015-01-01

Maturation of mRNA precursors often occurs simultaneously with their synthesis by RNA polymerase II (Pol II). The co-transcriptional nature of mRNA processing has permitted the evolution of coupling mechanisms that coordinate transcription with mRNA capping, splicing, editing and 3′ end formation. Recent experiments using sophisticated new methods for analysis of nascent RNA have provided important insights into the relative amount of co-transcriptional and post-transcriptional processing, the relationship between mRNA elongation and processing, and the role of the Pol II carboxy-terminal domain (CTD) in regulating these processes. PMID:24514444

Integrating mRNA and Protein Sequencing Enables the Detection and Quantitative Profiling of Natural Protein Sequence Variants of Populus trichocarpa.

PubMed

Abraham, Paul E; Wang, Xiaojing; Ranjan, Priya; Nookaew, Intawat; Zhang, Bing; Tuskan, Gerald A; Hettich, Robert L

2015-12-04

Next-generation sequencing has transformed the ability to link genotypes to phenotypes and facilitates the dissection of genetic contribution to complex traits. However, it is challenging to link genetic variants with the perturbed functional effects on proteins encoded by such genes. Here we show how RNA sequencing can be exploited to construct genotype-specific protein sequence databases to assess natural variation in proteins, providing information about the molecular toolbox driving cellular processes. For this study, we used two natural genotypes selected from a recent genome-wide association study of Populus trichocarpa, an obligate outcrosser with tremendous phenotypic variation across the natural population. This strategy allowed us to comprehensively catalogue proteins containing single amino acid polymorphisms (SAAPs), as well as insertions and deletions. We profiled the frequency of 128 types of naturally occurring amino acid substitutions, including both expected (neutral) and unexpected (non-neutral) SAAPs, with a subset occurring in regions of the genome having strong polymorphism patterns consistent with recent positive and/or divergent selection. By zeroing in on the molecular signatures of these important regions that might have previously been uncharacterized, we now provide a high-resolution molecular inventory that should improve accessibility and subsequent identification of natural protein variants in future genotype-to-phenotype studies.

Attentional responses to stimuli associated with a reward can occur in the absence of knowledge of their predictive values.

PubMed

Leganes-Fonteneau, Mateo; Scott, Ryan; Duka, Theodora

2018-04-02

Classical conditioning theories of addiction suggest that stimuli associated with rewards acquire incentive salience, inducing emotional and attentional conditioned responses. It is not clear whether those responses occur without contingency awareness (CA), i.e. are based on explicit or implicit learning processes. Examining implicit aspects of stimulus-reward associations can improve our understanding of addictive behaviours, supporting treatment and prevention strategies. However, the acquisition of conditioned responses without CA has yet to be rigorously demonstrated, as the existing literature shows a lack of methodological agreement regarding the measurement of implicit and explicit processes. The purpose of two experiments presented here was to study the emotional value acquired by CS through implicit emotional and attentional processes, trying to overcome critical methodological issues. Experiment 1 (n = 48) paired two stimuli categories (houses/buildings) with high (HR) or low (LR) probabilities of monetary reward. An Emotional Attentional Blink revealed preferential attention for HR over LR regardless of CA; while pleasantness ratings were unaffected, probably due to the intrinsic nature of CS. Experiment 2 (n = 60) replicated the effect of conditioning on the Emotional Attentional Blink utilising abstract CS (octagons/squares). In addition increased pleasantness for HR over LR was found significant overall, and marginally significant for Aware but not for Unaware participants. Here CA was rigorously determined using a signal-detection analysis and metacognitive-awareness measurements. Bayesian analyses verified the unconscious nature of the learning. These findings demonstrate that attentional conditioned responses can occur without CA and advance our understanding of the mechanisms by which implicit conditioning can occur and becomes observable. Furthermore, these results can highlight how addictive behaviours might develop. Copyright © 2017 Elsevier B.V. All rights reserved.

Robot path planning using expert systems and machine vision

NASA Astrophysics Data System (ADS)

Malone, Denis E.; Friedrich, Werner E.

1992-02-01

This paper describes a system developed for the robotic processing of naturally variable products. In order to plan the robot motion path it was necessary to use a sensor system, in this case a machine vision system, to observe the variations occurring in workpieces and interpret this with a knowledge based expert system. The knowledge base was acquired by carrying out an in-depth study of the product using examination procedures not available in the robotic workplace and relates the nature of the required path to the information obtainable from the machine vision system. The practical application of this system to the processing of fish fillets is described and used to illustrate the techniques.

Adaptive Colour Contrast Coding in the Salamander Retina Efficiently Matches Natural Scene Statistics

PubMed Central

Vasserman, Genadiy; Schneidman, Elad; Segev, Ronen

2013-01-01

The visual system continually adjusts its sensitivity to the statistical properties of the environment through an adaptation process that starts in the retina. Colour perception and processing is commonly thought to occur mainly in high visual areas, and indeed most evidence for chromatic colour contrast adaptation comes from cortical studies. We show that colour contrast adaptation starts in the retina where ganglion cells adjust their responses to the spectral properties of the environment. We demonstrate that the ganglion cells match their responses to red-blue stimulus combinations according to the relative contrast of each of the input channels by rotating their functional response properties in colour space. Using measurements of the chromatic statistics of natural environments, we show that the retina balances inputs from the two (red and blue) stimulated colour channels, as would be expected from theoretical optimal behaviour. Our results suggest that colour is encoded in the retina based on the efficient processing of spectral information that matches spectral combinations in natural scenes on the colour processing level. PMID:24205373

Serum angiotensin-1 converting enzyme activity processes a human immunodeficiency virus 1 gp160 peptide for presentation by major histocompatibility complex class I molecules

PubMed Central

1992-01-01

T cell stimulation by the human immunodeficiency virus 1 gp160-derived peptide p18 presented by H-2Dd class I major histocompatibility complex molecules in a cell-free system was found to require proteolytic cleavage. This extracellular processing was mediated by peptidases present in fetal calf serum. In vitro processing of p18 resulted in a distinct reverse phase high performance liquid chromatography profile, from which a biologically active product was isolated and sequenced. This peptide processing can be specifically blocked by the angiotensin- 1 converting enzyme (ACE) inhibitor captopril, and can occur by exposing p18 to purified ACE. The ability of naturally occurring extracellular proteases to convert inactive peptides to T cell antigens has important implications for understanding cytotoxic T lymphocyte responses in vivo, and for rational peptide vaccine design. PMID:1316930

Analogues to features and processes of a high-level radioactive waste repository proposed for Yucca Mountain, Nevada

USGS Publications Warehouse

Simmons, Ardyth M.; Stuckless, John S.; with a Foreword by Abraham Van Luik, U.S. Department of Energy

2010-01-01

Natural analogues are defined for this report as naturally occurring or anthropogenic systems in which processes similar to those expected to occur in a nuclear waste repository are thought to have taken place over time periods of decades to millennia and on spatial scales as much as tens of kilometers. Analogues provide an important temporal and spatial dimension that cannot be tested by laboratory or field-scale experiments. Analogues provide one of the multiple lines of evidence intended to increase confidence in the safe geologic disposal of high-level radioactive waste. Although the work in this report was completed specifically for Yucca Mountain, Nevada, as the proposed geologic repository for high-level radioactive waste under the U.S. Nuclear Waste Policy Act, the applicability of the science, analyses, and interpretations is not limited to a specific site. Natural and anthropogenic analogues have provided and can continue to provide value in understanding features and processes of importance across a wide variety of topics in addressing the challenges of geologic isolation of radioactive waste and also as a contribution to scientific investigations unrelated to waste disposal. Isolation of radioactive waste at a mined geologic repository would be through a combination of natural features and engineered barriers. In this report we examine analogues to many of the various components of the Yucca Mountain system, including the preservation of materials in unsaturated environments, flow of water through unsaturated volcanic tuff, seepage into repository drifts, repository drift stability, stability and alteration of waste forms and components of the engineered barrier system, and transport of radionuclides through unsaturated and saturated rock zones.

Top-down preparation modulates visual categorization but not subjective awareness of objects presented in natural backgrounds.

PubMed

Koivisto, Mika; Kahila, Ella

2017-04-01

Top-down processes are widely assumed to be essential in visual awareness, subjective experience of seeing. However, previous studies have not tried to separate directly the roles of different types of top-down influences in visual awareness. We studied the effects of top-down preparation and object substitution masking (OSM) on visual awareness during categorization of objects presented in natural scene backgrounds. The results showed that preparation facilitated categorization but did not influence visual awareness. OSM reduced visual awareness and impaired categorization. The dissociations between the effects of preparation and OSM on visual awareness and on categorization imply that they influence at different stages of cognitive processing. We propose that preparation influences at the top of the visual hierarchy, whereas OSM interferes with processes occurring at lower levels of the hierarchy. These lower level processes play an essential role in visual awareness. Copyright © 2017 Elsevier Ltd. All rights reserved.

Natural asynchronies in audiovisual communication signals regulate neuronal multisensory interactions in voice-sensitive cortex.

PubMed

Perrodin, Catherine; Kayser, Christoph; Logothetis, Nikos K; Petkov, Christopher I

2015-01-06

When social animals communicate, the onset of informative content in one modality varies considerably relative to the other, such as when visual orofacial movements precede a vocalization. These naturally occurring asynchronies do not disrupt intelligibility or perceptual coherence. However, they occur on time scales where they likely affect integrative neuronal activity in ways that have remained unclear, especially for hierarchically downstream regions in which neurons exhibit temporally imprecise but highly selective responses to communication signals. To address this, we exploited naturally occurring face- and voice-onset asynchronies in primate vocalizations. Using these as stimuli we recorded cortical oscillations and neuronal spiking responses from functional MRI (fMRI)-localized voice-sensitive cortex in the anterior temporal lobe of macaques. We show that the onset of the visual face stimulus resets the phase of low-frequency oscillations, and that the face-voice asynchrony affects the prominence of two key types of neuronal multisensory responses: enhancement or suppression. Our findings show a three-way association between temporal delays in audiovisual communication signals, phase-resetting of ongoing oscillations, and the sign of multisensory responses. The results reveal how natural onset asynchronies in cross-sensory inputs regulate network oscillations and neuronal excitability in the voice-sensitive cortex of macaques, a suggested animal model for human voice areas. These findings also advance predictions on the impact of multisensory input on neuronal processes in face areas and other brain regions.

BIRDS AS A MODEL TO STUDY ADULT NEUROGENESIS: BRIDGING EVOLUTIONARY, COMPARATIVE AND NEUROETHOLOGICAL APPROCHES

PubMed Central

BARNEA, ANAT; PRAVOSUDOV, VLADIMIR

2011-01-01

During the last few decades evidence has demonstrated that adult neurogenesis is a well-preserved feature throughout the animal kingdom. In birds, ongoing neuronal addition occurs rather broadly, to a number of brain regions. This review describes adult avian neurogenesis and neuronal recruitment, discusses factors that regulate these processes, and touches upon the question of their genetic control. Several attributes make birds an extremely advantageous model to study neurogenesis. First, song learning exhibits seasonal variation that is associated with seasonal variation in neuronal turnover in some song control brain nuclei, which seems to be regulated via adult neurogenesis. Second, food-caching birds naturally use memory-dependent behavior in learning locations of thousands of food caches scattered over their home ranges. In comparison with other birds, food-caching species have relatively enlarged hippocampi with more neurons and intense neurogenesis, which appears to be related to spatial learning. Finally, migratory behavior and naturally occurring social systems in birds also provide opportunities to investigate neurogenesis. Such diversity of naturally-occurring memory-based behaviors, combined with the fact that birds can be studied both in the wild and in the laboratory, make them ideal for investigation of neural processes underlying learning. This can be done by using various approaches, from evolutionary and comparative to neuroethological and molecular. Finally, we connect the avian arena to a broader view by providing a brief comparative and evolutionary overview of adult neurogenesis and by discussing the possible functional role of the new neurons. We conclude by indicating future directions and possible medical applications. PMID:21929623

Bacterial Interactions with CdSe Quantum Dots

NASA Astrophysics Data System (ADS)

Holden, P.; Nadeau, J. L.; Kumar, A.; Clarke, S.; Priester, J. H.; Stucky, G. D.

2007-12-01

Cadmium selenide quantum dots (QDs) are semiconductor nanoparticles that are manufactured for biomedical imaging, photovoltaics, and other applications. While metallic nanoparticles can be made biotically by bacteria and fungi, and thus occur in nature, the fate of either natural or engineered QDs and relationships to nanoparticle size, conjugate and biotic conditions are mostly unknown. Working with several different bacterial strains and QDs of different sizes and conjugate chemistries, including QDs synthesized by a Fusarium fungal strain, we show that QDs can enter cells through specfic receptor-mediated processes, that QDs are broken down by bacteria during cell association, and that toxicity to cells is much like that imposed by Cd(II) ions. The mechanisms of entry and toxicity are not fully understood, but preliminary evidence suggests that electron transfer between cells and QDs occurs. Also, cell membranes are compromised, indicating oxidative stress is occurring. Results with planktonic and biofilm bacteria are similar, but differently, biofilms tend to accumulate Cd(II) associated with QD treatments.

Natural Organohalogens: A New Frontier for Medicinal Agents?

NASA Astrophysics Data System (ADS)

Gribble, Gordon W.

2004-10-01

More than 4000 naturally occurring organohalogen compounds are known. These include a relatively small number of abiogenic organohalogens from volcanoes, forest fires, geothermal processes, and meteorites, and a very large number of biogenic organohalogens produced by myriad living organisms as part of their chemical makeup that serve as hormones, pheromones, repellents, and natural pesticides. From the chemically simple methyl chloride, methyl bromide, and chloroform to the structurally complex vancomycin, pyrroindomycin, and bastadins, the diversity of these organohalogens is unsurpassed among natural products. Most natural organohalogens contain chlorine (2300) or bromine (2100), but a significant number contain iodine (120) or fluorine (30). Several hundred marine natural products contain both chlorine and bromine. The present article focuses on newly discovered biogenic organohalogens, with an emphasis on those biologically active examples from marine organisms, bacteria, terrestrial plants, and higher life forms including humans.

Automated detection using natural language processing of radiologists recommendations for additional imaging of incidental findings.

PubMed

Dutta, Sayon; Long, William J; Brown, David F M; Reisner, Andrew T

2013-08-01

As use of radiology studies increases, there is a concurrent increase in incidental findings (eg, lung nodules) for which the radiologist issues recommendations for additional imaging for follow-up. Busy emergency physicians may be challenged to carefully communicate recommendations for additional imaging not relevant to the patient's primary evaluation. The emergence of electronic health records and natural language processing algorithms may help address this quality gap. We seek to describe recommendations for additional imaging from our institution and develop and validate an automated natural language processing algorithm to reliably identify recommendations for additional imaging. We developed a natural language processing algorithm to detect recommendations for additional imaging, using 3 iterative cycles of training and validation. The third cycle used 3,235 radiology reports (1,600 for algorithm training and 1,635 for validation) of discharged emergency department (ED) patients from which we determined the incidence of discharge-relevant recommendations for additional imaging and the frequency of appropriate discharge documentation. The test characteristics of the 3 natural language processing algorithm iterations were compared, using blinded chart review as the criterion standard. Discharge-relevant recommendations for additional imaging were found in 4.5% (95% confidence interval [CI] 3.5% to 5.5%) of ED radiology reports, but 51% (95% CI 43% to 59%) of discharge instructions failed to note those findings. The final natural language processing algorithm had 89% (95% CI 82% to 94%) sensitivity and 98% (95% CI 97% to 98%) specificity for detecting recommendations for additional imaging. For discharge-relevant recommendations for additional imaging, sensitivity improved to 97% (95% CI 89% to 100%). Recommendations for additional imaging are common, and failure to document relevant recommendations for additional imaging in ED discharge instructions occurs frequently. The natural language processing algorithm's performance improved with each iteration and offers a promising error-prevention tool. Copyright © 2013 American College of Emergency Physicians. Published by Mosby, Inc. All rights reserved.

Stimulus background influences phase invariant coding by correlated neural activity

PubMed Central

Metzen, Michael G; Chacron, Maurice J

2017-01-01

Previously we reported that correlations between the activities of peripheral afferents mediate a phase invariant representation of natural communication stimuli that is refined across successive processing stages thereby leading to perception and behavior in the weakly electric fish Apteronotus leptorhynchus (Metzen et al., 2016). Here, we explore how phase invariant coding and perception of natural communication stimuli are affected by changes in the sinusoidal background over which they occur. We found that increasing background frequency led to phase locking, which decreased both detectability and phase invariant coding. Correlated afferent activity was a much better predictor of behavior as assessed from both invariance and detectability than single neuron activity. Thus, our results provide not only further evidence that correlated activity likely determines perception of natural communication signals, but also a novel explanation as to why these preferentially occur on top of low frequency as well as low-intensity sinusoidal backgrounds. DOI: http://dx.doi.org/10.7554/eLife.24482.001 PMID:28315519

Teaching in hunter–gatherer infancy

PubMed Central

Hewlett, Barry S.; Roulette, Casey J.

2016-01-01

A debate exists as to whether teaching is part of human nature and central to understanding culture or whether it is a recent invention of Western, Educated, Industrial, Rich, Democratic cultures. Some social–cultural anthropologists and cultural psychologists indicate teaching is rare in small-scale cultures while cognitive psychologists and evolutionary biologists indicate it is universal and key to understanding human culture. This study addresses the following questions: Does teaching of infants exist in hunter–gatherers? If teaching occurs in infancy, what skills or knowledge is transmitted by this process, how often does it occur and who is teaching? The study focuses on late infancy because cognitive psychologists indicate that one form of teaching, called natural pedagogy, emerges at this age. Videotapes of Aka hunter–gatherer infants were used to evaluate whether or not teaching exists among Aka hunter–gatherers of central Africa. The study finds evidence of multiple forms of teaching, including natural pedagogy, that are used to enhance learning of a variety of skills and knowledge. PMID:26909166

Natural disaster management in India with focus on floods and cyclones

NASA Astrophysics Data System (ADS)

Thattai, Deeptha V.; Sathyanathan, R.; Dinesh, R.; Harshit Kumar, L.

2017-07-01

Disasters are of two major kinds, natural and manmade, and affect the community. Natural disasters are caused by natural earth processes like floods, droughts, cyclones, tsunamis, earthquakes and epidemics. Manmade disasters occur due to chemical spills, accidents, terrorism activities etc. India is prone to almost all the major natural disasters. The high population density combined with poor preparedness, planning and management, and rescue and relief measures inevitably lead to huge losses of lives and property every year in the country. This paper analyses the disaster management policy of India and its implementation using two recent case studies - one where a relative degree of success has been achieved (cyclones) and the other where we are still struggling to have even a basic preparedness system in place (floods).

Development of a method to manufacture uncured, no-nitrate/nitrite-added whole muscle jerky.

PubMed

Sindelar, Jeffrey J; Terns, Matthew J; Meyn, Elizabeth; Boles, Jane A

2010-10-01

"Natural curing" is accomplished by use of vegetable juice/powder high in naturally occurring nitrates combined with a nitrate reducing starter culture to result in indirectly "cured" products. Since the starter culture used is not water soluble, making "naturally cured" whole muscle jerky with current manufacturing techniques has been found ineffective. The objective was to investigate processes for whole muscle beef jerky that might provide cured meat characteristics similar to those of a nitrite-added control. Treatments where jerky was placed in a barrier bag during incubation were found to be the least similar to the nitrite-added control. Jerky placed in a 40.6 degrees C smokehouse during incubation resulted in significantly more (P<0.05) converted cured pigment than the barrier bag treatments but less (P<0.05) than the control. The processing methods investigated to manufacture "naturally cured" whole muscle jerky in this study were ineffective in resulting in products similar to those cured with sodium nitrite. Published by Elsevier Ltd.

Treatment of waste water by coagulation and flocculation using biomaterials

NASA Astrophysics Data System (ADS)

Muruganandam, L.; Saravana Kumar, M. P.; Jena, Amarjit; Gulla, Sudiv; Godhwani, Bhagesh

2017-11-01

The present study deals with the determination of physical and chemical parameters in the treatment process of waste water by flocculation and coagulation processes using natural coagulants and assessing their feasibility for water treatment by comparing the performance with each other and with a synthetic coagulant. Initial studies were done on the synthetic waste water to determine the optimal pH and dosage, the activity of natural coagulant, followed by the real effluent from tannery waste. The raw tannery effluent was bluish-black in colour, mildly basic in nature, with high COD 4000mg/l and turbidity in the range 700NTU, was diluted and dosed with organic coagulants, AloeVera, MoringaOleifera and Cactus (O.ficus-indica). The study observed that coagulant Moringa Oleifera of 15 mg/L dose at 6 pH gave the best reduction efficiencies for major physicochemical parameters followed by Aloe Vera and Cactus under identical conditions. The study reveals that the untreated tannery effluents can be treated with environmental confirmative naturally occurring coagulants.

NaturAnalogs for the Unsaturated Zone

DOE Office of Scientific and Technical Information (OSTI.GOV)

A. Simmons; A. Unger; M. Murrell

2000-03-08

The purpose of this Analysis/Model Report (AMR) is to document natural and anthropogenic (human-induced) analog sites and processes that are applicable to flow and transport processes expected to occur at the potential Yucca Mountain repository in order to build increased confidence in modeling processes of Unsaturated Zone (UZ) flow and transport. This AMR was prepared in accordance with ''AMR Development Plan for U0135, Natural Analogs for the UZ'' (CRWMS 1999a). Knowledge from analog sites and processes is used as corroborating information to test and build confidence in flow and transport models of Yucca Mountain, Nevada. This AMR supports the Unsaturatedmore » Zone (UZ) Flow and Transport Process Model Report (PMR) and the Yucca Mountain Site Description. The objectives of this AMR are to test and build confidence in the representation of UZ processes in numerical models utilized in the UZ Flow and Transport Model. This is accomplished by: (1) applying data from Boxy Canyon, Idaho in simulations of UZ flow using the same methodologies incorporated in the Yucca Mountain UZ Flow and Transport Model to assess the fracture-matrix interaction conceptual model; (2) Providing a preliminary basis for analysis of radionuclide transport at Pena Blanca, Mexico as an analog of radionuclide transport at Yucca Mountain; and (3) Synthesizing existing information from natural analog studies to provide corroborating evidence for representation of ambient and thermally coupled UZ flow and transport processes in the UZ Model.« less

On the role of entailment patterns and scalar implicatures in the processing of numerals

PubMed Central

Panizza, Daniele; Chierchia, Gennaro; Clifton, Charles

2009-01-01

There has been much debate, in both the linguistics and the psycholinguistics literature, concerning numbers and the interpretation of number denoting determiners ('numerals'). Such debate concerns, in particular, the nature and distribution of upper-bounded ('at-least') interpretations vs. lower-bounded ('exact') construals. In the present paper we show that the interpretation and processing of numerals are affected by the entailment properties of the context in which they occur. Experiment 1 established off-line preferences using a questionnaire. Experiment 2 investigated the processing issue through an eye tracking experiment using a silent reading task. Our results show that the upper-bounded interpretation of numerals occurs more often in an upward entailing context than in a downward entailing context. Reading times of the numeral itself were longer when it was embedded in an upward entailing context than when it was not, indicating that processing resources were required when the context triggered an upper-bounded interpretation. However, reading of a following context that required an upper-bounded interpretation triggered more regressions towards the numeral when it had occurred in a downward entailing context than in an upward entailing one. Such findings show that speakers' interpretation and processing of numerals is systematically affected by the polarity of the sentence in which they occur, and support the hypothesis that the upper-bounded interpretation of numerals is due to a scalar implicature. PMID:20161494

Modelling methane emissions from natural wetlands by development and application of the TRIPLEX-GHG model

USGS Publications Warehouse

Zhu, Qing; Liu, Jinxun; Peng, C.; Chen, H.; Fang, X.; Jiang, H.; Yang, G.; Zhu, D.; Wang, W.; Zhou, X.

2014-01-01

A new process-based model TRIPLEX-GHG was developed based on the Integrated Biosphere Simulator (IBIS), coupled with a new methane (CH4) biogeochemistry module (incorporating CH4 production, oxidation, and transportation processes) and a water table module to investigate CH4 emission processes and dynamics that occur in natural wetlands. Sensitivity analysis indicates that the most sensitive parameters to evaluate CH4 emission processes from wetlands are r (defined as the CH4 to CO2 release ratio) and Q10 in the CH4 production process. These two parameters were subsequently calibrated to data obtained from 19 sites collected from approximately 35 studies across different wetlands globally. Being heterogeneously spatially distributed, r ranged from 0.1 to 0.7 with a mean value of 0.23, and the Q10 for CH4 production ranged from 1.6 to 4.5 with a mean value of 2.48. The model performed well when simulating magnitude and capturing temporal patterns in CH4 emissions from natural wetlands. Results suggest that the model is able to be applied to different wetlands under varying conditions and is also applicable for global-scale simulations.

Naturally occurring diacetyl and 2,3-pentanedione concentrations associated with roasting and grinding unflavored coffee beans in a commercial setting.

PubMed

Gaffney, Shannon H; Abelmann, Anders; Pierce, Jennifer S; Glynn, Meghan E; Henshaw, John L; McCarthy, Lauren A; Lotter, Jason T; Liong, Monty; Finley, Brent L

2015-01-01

Over the last decade, concerns have been raised about potential respiratory health effects associated with occupational exposure to the flavoring additives diacetyl and 2,3-pentanedione. Both of these diketones are also natural components of many foods and beverages, including roasted coffee. To date, there are no published studies characterizing workplace exposures to these diketones during commercial roasting and grinding of unflavored coffee beans. In this study, we measured naturally occurring diacetyl, 2,3-pentanedione, and respirable dust at a facility that roasts and grinds coffee beans with no added flavoring agents. Sampling was conducted over the course of three roasting batches and three grinding batches at varying distances from a commercial roaster and grinder. The three batches consisted of lightly roasted soft beans, lightly roasted hard beans, and dark roasted hard beans. Roasting occurred for 37 to 41 min, and the grinding process took between 8 and 11 min. Diacetyl, 2,3-pentanedione, and respirable dust concentrations measured during roasting ranged from less than the limit of detection (

Investigating the Relationship between Curiosity Level and Computer Self Efficacy Beliefs of Elementary Teachers Candidates

ERIC Educational Resources Information Center

Gulten, Dilek Cagirgan; Yaman, Yavuz; Deringol, Yasemin; Ozsari, Ismail

2011-01-01

Nowadays, "lifelong learning individual" concept is gaining importance in which curiosity is one important feature that an individual should have as a requirement of learning. It is known that learning will naturally occur spontaneously when curiosity instinct is awakened during any learning-teaching process. Computer self-efficacy…

NON-REGULATED CONTAMINANTS EMERGING RESEARCH, EXISTING AND FUTURE POLLUTANTS IN WATER SUPPLIES: OLD POLLUTANTS, NEW CONCERNS - NEW POLLUTANTS, UNKNOWN ISSUES

EPA Science Inventory

Those chemical pollutants that are regulated under various international, federal, and state programs represent but a small fraction of the universe of chemicals that occur in the environment as a result of both natural processes and human influence. Although this galaxy of targe...

Academic Entrepreneurship, Innovation Policies and Politics in Greece

ERIC Educational Resources Information Center

Arapostathis, Stathis

2010-01-01

This paper explores the process of the emergence in Greece of the "Triple Helix", and the nature of the "Helix" in the context of the concurrent changes occurring in Greek socio-political affairs. The influence of politics and innovation policies on the relationships between academia and government and industry is considered.…

Winging It: Using Digital Imaging To Investigate Butterfly Metamorphosis

ERIC Educational Resources Information Center

Bowen, Anne; Bell, Randy L.

2004-01-01

One of the best ways to inspire interest in biology is through observations of living things. Unfortunately, this important component of science methodology is often left out because of the difficulty of including it in the classroom. Additionally, amazing processes occur in nature that few have the chance to observe. This article reviews a…

Climate and atmospheric deposition patterns and trends

Treesearch

Warren E. Heilman; John Hom; Brian E. Potter

2000-01-01

One of the most important factors impacting terrestrial and aquatic ecosystems is the atmospheric environment. Climatic and weather events play a significant role in governing the natural processes that occur in these ecosystems. The current characteristics of the vast number of ecosystems that cover the northeast and north central United States are, in part, the...

Forecasting gypsy moth egg-mass density

Treesearch

Robert W. Campbell; Robert W. Campbell

1973-01-01

Several multiple regression models for gypsy moth egg-mass density were developed from data accumulated in eastern New England between 1911 and 1931. Analysis of these models indicates that: (1) The gypsy moth population system was relatively stable in either the OUTBREAK phase or the INNOCUOUS one; (2) Several naturally occurring processes that could terminate the...

Understanding Recovery from Object Substitution Masking

ERIC Educational Resources Information Center

Goodhew, Stephanie C.; Dux, Paul E.; Lipp, Ottmar V.; Visser, Troy A. W.

2012-01-01

When we look at a scene, we are conscious of only a small fraction of the available visual information at any given point in time. This raises profound questions regarding how information is selected, when awareness occurs, and the nature of the mechanisms underlying these processes. One tool that may be used to probe these issues is…

Language Acquisition by Children with Down Syndrome: A Naturalistic Approach to Assisting Language Acquisition

ERIC Educational Resources Information Center

Vilaseca, R.M.; Del Rio, M-J.

2004-01-01

Many child language studies emphasize the value of verbal and social support, of 'scaffolding' processes and mutual adjustments that naturally occur in adult-child interactions in everyday contexts. Based on such theories, this study attempted to improve the language and communication skills in children with special educational needs through…

Chapter 5 - Tree Mortality

Treesearch

Mark J. Ambrose

2018-01-01

Tree mortality is a natural process in all forest ecosystems. High mortality can be an indicator of forest health problems. On aregional scale, high mortality levels may indicate widespread insect or disease impacts. High mortality may also occur if a large proportion of the forest in a particular region is made up of older, senescent stands. The approach...

Bringing an ecological view of change to Landsat-based remote sensing

Treesearch

Robert E. Kennedy; Serge Andrefouet; Warren B. Cohen; Cristina Gomez; Patrick Griffiths; Martin Hais; Sean P. Healey; Eileen H. Helmer; Patrick Hostert; Mitchell B. Lyons; Garrett W. Meigs; Dirk Pflugmacher; Stuart R. Phinn; Scott L. Powell; Peter Scarth; Susmita Sen; Todd A. Schroeder; Annemarie Schneider; Ruth Sonnenschein; James E. Vogelmann; Michael A. Wulder; Zhe Zhu

2014-01-01

When characterizing the processes that shape ecosystems, ecologists increasingly use the unique perspective offered by repeat observations of remotely sensed imagery. However, the concept of change embodied in much of the traditional remote-sensing literature was primarily limited to capturing large or extreme changes occurring in natural systems, omitting many more...

Expanding horizons. Integrating environmental health in occupational health nursing.

PubMed

Rogers, B; Cox, A R

1998-01-01

1. Environmental hazards are ubiquitous. Many exist in the workplace or occur as a result of work process exposures. 2. Environmental health is a natural component of the expanding practice of occupational health nursing. 3. AAOHN's vision for occupational and environmental health will continue to set the standard and provide leadership in the specialty.

Safely Caring for Animals during Inquiry Investigations: Exploring Microecosystems

ERIC Educational Resources Information Center

Marek, Edmund A.; Parker, Chad A.

2010-01-01

"Science is a process of discovering and exploring the natural world. Exploration occurs in the classroom, laboratory or in the field. As part of your science class, you will be doing many activities and investigations that will involve the use of various materials, equipment, and chemicals…" (NSTA, 2010). Safety is always of utmost…

Nursing Students' Perception of Conflict Management Styles of Their Nursing Educators

ERIC Educational Resources Information Center

Hashish, Ebtsam Aly Abou; Hamouda, Ghada Mohamed; Taha, Eman El-Sayed

2015-01-01

Background: The interactive nature of the teaching process is built on a social relationship between teachers and students. Conflicts in the relationship between students and teachers may occur for a several reasons. Effective and constructive management of conflict can decrease its negative effects on the learning environment, students, and…

Aquatic Species Program Review: Proceedings of the March 1983 Principal Investigators Meeting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1983-06-01

The Aquatic Species Program (ASP) addresses the utilization of plant biomass that naturally occurs in wetland or submerged areas. Processes are being developed through this program to make use of such aquatic species, capitalizing on their inherent capacity for rapid growth as well as their extraordinary chemical compositions.

Primal Theatre

ERIC Educational Resources Information Center

Rubin, Alec

1976-01-01

Defines primal therapy as an approach to growth and change the goal of which is to rediscover the real self, the natural child. Relates this concept to primal theatre where an effort is made to express on stage what rarely occurs in life and what is usually hidden. Basic processes for primal theatre workshops are discussed. For availability see CS…

Examining an Evolution: A Case Study of Organizational Change Accompanying the Community College Baccalaureate

ERIC Educational Resources Information Center

McKinney, Lyle; Morris, Phillip A.

2010-01-01

This study examined the nature and degree of organizational change that occurs when community colleges offer their own baccalaureate degree programs. Utilizing qualitative research methodology, we investigated how executive administrators at two Florida colleges managed this momentous change process and how this transformation has affected their…

Tree Mortality

Treesearch

Mark J. Ambrose

2011-01-01

Tree mortality is a natural process in all forest ecosystems, but it can also be an indicator of forest health issues. On a regional scale, high-mortality levels may indicate widespread insect or disease problems. Regionally high mortality may also occur if a large proportion of the forests in an area are made up of older, senescent stands.

Readings in Computer Based Guidance. The Bartlesville System.

ERIC Educational Resources Information Center

Bartlesville Public Schools, OK.

The document contains six papers which deal with the need for change in guidance and counseling due to the overwhelming amount of data which is insufficiently processed by conventional manual systems. Included in these papers are discussions on when these changes should occur and the nature of their alterations. The reports consider some of the…

Tree Mortality

Treesearch

Mark J. Ambrose

2012-01-01

Tree mortality is a natural process in all forest ecosystems. However, extremely high mortality also can be an indicator of forest health issues. On a regional scale, high mortality levels may indicate widespread insect or disease problems. High mortality may also occur if a large proportion of the forest in a particular region is made up of older, senescent stands....

Natural ageing process accelerates the release of Ag from functional textile in various exposure scenarios

PubMed Central

Ding, Dahu; Chen, Lulu; Dong, Shaowei; Cai, Hao; Chen, Jifei; Jiang, Canlan; Cai, Tianming

2016-01-01

Natural ageing process occurs throughout the life cycle of textile products, which may possess influences on the release behavior of additives such as silver nanoparticles (Ag NPs). In this study, we assessed the releasability of Ag NPs from a Ag NPs functionalized textile in five different exposure scenarios (i.e. tap water (TW), pond water (PW), rain water (RW), artificial sweat (AS), and detergent solution (DS) along with deionized water (DW) as reference), which were very likely to occur throughout the life cycle of the textile. For the pristine textile, although the most remarkable release was found in DW (6–15 μg Ag/g textile), the highest release rate was found in RW (around 7 μg Ag/(g textile·h)). After ageing treatment, the total released Ag could be increased by 75.7~386.0% in DW, AS and DS. Morphological analysis clearly showed that the Ag NPs were isolated from the surface of the textile fibre due to the ageing treatment. This study provides useful information for risk assessment of nano-enhanced textile products. PMID:27869136

Natural ageing process accelerates the release of Ag from functional textile in various exposure scenarios

NASA Astrophysics Data System (ADS)

Ding, Dahu; Chen, Lulu; Dong, Shaowei; Cai, Hao; Chen, Jifei; Jiang, Canlan; Cai, Tianming

2016-11-01

Natural ageing process occurs throughout the life cycle of textile products, which may possess influences on the release behavior of additives such as silver nanoparticles (Ag NPs). In this study, we assessed the releasability of Ag NPs from a Ag NPs functionalized textile in five different exposure scenarios (i.e. tap water (TW), pond water (PW), rain water (RW), artificial sweat (AS), and detergent solution (DS) along with deionized water (DW) as reference), which were very likely to occur throughout the life cycle of the textile. For the pristine textile, although the most remarkable release was found in DW (6-15 μg Ag/g textile), the highest release rate was found in RW (around 7 μg Ag/(g textile·h)). After ageing treatment, the total released Ag could be increased by 75.7~386.0% in DW, AS and DS. Morphological analysis clearly showed that the Ag NPs were isolated from the surface of the textile fibre due to the ageing treatment. This study provides useful information for risk assessment of nano-enhanced textile products.

Humidity control as a strategy for lattice optimization applied to crystals of HLA-A*1101 complexed with variant peptides from dengue virus

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chotiyarnwong, Pojchong; Medical Molecular Biology Unit, Faculty of Medicine, Siriraj Hospital, Mahidol University; Stewart-Jones, Guillaume B.

Crystals of an MHC class I molecule bound to naturally occurring peptide variants from the dengue virus NS3 protein contained high levels of solvent and required optimization of cryoprotectant and dehydration protocols for each complex to yield well ordered diffraction, a process facilitated by the use of a free-mounting system. T-cell recognition of the antigenic peptides presented by MHC class I molecules normally triggers protective immune responses, but can result in immune enhancement of disease. Cross-reactive T-cell responses may underlie immunopathology in dengue haemorrhagic fever. To analyze these effects at the molecular level, the functional MHC class I molecule HLA-A*1101more » was crystallized bound to six naturally occurring peptide variants from the dengue virus NS3 protein. The crystals contained high levels of solvent and required optimization of the cryoprotectant and dehydration protocols for each complex to yield well ordered diffraction, a process that was facilitated by the use of a free-mounting system.« less

Microwave (MW) promoted high yield expedient synthesis of steryl ferulates--A class of novel biologically active compounds: A comparative study of their antioxidant activity with that of naturally occurring γ-oryzanol.

PubMed

Begum, Ashma; Borah, Preetismita; Chowdhury, Pritish

2016-03-01

Synthetic steryl ferulates [3-O-(trans-4-feruloyl)-sterols] are currently gaining considerable importance in recent years to be used as nutraceuticals and food additives as well as in pharmaceutical applications substituting γ-oryzanol - a class of naturally occurring steryl ferulates having potent antioxidant and other organoleptic properties. Considering the importance of this class of compounds coupled with green technology associated with microwave energy (MW) in organic synthesis, we report here an expedited and high yield synthesis of steryl ferulates from abundant steroids, viz., cholesterol, cholestanol, stigmasterol, stigmastanol, β-sitosterol, β-campesterol, β-campestanol and ergosterol applying MW energy in the crucial step of esterification process of sterols with trans-4-O-acetylferulic acid to furnish their esterified products, viz., 3-O-(trans-4-O-acetylferuloyl)-sterols for their eventual deprotection to their respective steryl ferulates. We further report an efficient and scalable process of producing acetylferulic acid. Testing of synthesized steryl ferulates against antioxidant assays has also been highlighted. Copyright © 2015 Elsevier Inc. All rights reserved.

[A NATURAL PLAGUE FOCUS. IN GORNYI ALTAI: FORMATION, DEVELOPMENT, AND FUNCTIONING].

PubMed

Korzun, V M; Balakhoiov, S V; Chpanin, E V; Denisov, A V; Mikhailov, E P; Mischenko, A J; Yarygina, M B; Rozhdestvensky, E N; Fomina, L A

2016-01-01

The paper gives the results of analyzing the data of long-term studies of the natural focal pattern of plague in the Gornyi Altai natural focus. It describes a wide range of biological processes occurring in the focus and shows the most important patterns of its functioning as a complex multilevel ecological system. The key features of the formation of the focus have been revealed. The plague focus in South-Western Altai has formed relatively, recently, about half a century ago, then it has intensively developed and its enzootic area and the activity of epizootic manifestations have considerably increased. This process is due to the space-time transformations of the basic ecological and population characteristics of Pallas' pika (Ochotoma pallasi), the principal vector of the pathogen of plague and fleas parasitizing the mammal, which is in turn related to the aridization of mountain steppes in South-Western Altai.

Storytelling, behavior planning, and language evolution in context.

PubMed

McBride, Glen

2014-01-01

An attempt is made to specify the structure of the hominin bands that began steps to language. Storytelling could evolve without need for language yet be strongly subject to natural selection and could provide a major feedback process in evolving language. A storytelling model is examined, including its effects on the evolution of consciousness and the possible timing of language evolution. Behavior planning is presented as a model of language evolution from storytelling. The behavior programming mechanism in both directions provide a model of creating and understanding behavior and language. Culture began with societies, then family evolution, family life in troops, but storytelling created a culture of experiences, a final step in the long process of achieving experienced adults by natural selection. Most language evolution occurred in conversations where evolving non-verbal feedback ensured mutual agreements on understanding. Natural language evolved in conversations with feedback providing understanding of changes.

Storytelling, behavior planning, and language evolution in context

PubMed Central

McBride, Glen

2014-01-01

An attempt is made to specify the structure of the hominin bands that began steps to language. Storytelling could evolve without need for language yet be strongly subject to natural selection and could provide a major feedback process in evolving language. A storytelling model is examined, including its effects on the evolution of consciousness and the possible timing of language evolution. Behavior planning is presented as a model of language evolution from storytelling. The behavior programming mechanism in both directions provide a model of creating and understanding behavior and language. Culture began with societies, then family evolution, family life in troops, but storytelling created a culture of experiences, a final step in the long process of achieving experienced adults by natural selection. Most language evolution occurred in conversations where evolving non-verbal feedback ensured mutual agreements on understanding. Natural language evolved in conversations with feedback providing understanding of changes. PMID:25360123

Physical nature of longevity of light actinides in dynamic failure phenomenon

DOE Office of Scientific and Technical Information (OSTI.GOV)

Uchaev, A. Ya., E-mail: uchaev@expd.vniief.ru; Punin, V. T.; Selchenkova, N. I.

It is shown in this work that the physical nature of the longevity of light actinides under extreme conditions in a range of nonequilibrium states of t ∼ 10{sup –6}–10{sup –10} s is determined by the time needed for the formation of a critical concentration of a cascade of failure centers, which changes connectivity of the body. These centers form a percolation cluster. The longevity is composed of waiting time t{sub w} for the appearance of failure centers and clusterization time t{sub c} of cascade of failure centers, when connectivity in the system of failure centers and the percolation clustermore » arise. A unique mechanism of the dynamic failure process, a unique order parameter, and an equal dimensionality of the space in which the process occurs determine the physical nature of the longevity of metals, including fissionable materials.« less

Photoacoustic Monitoring of Absorption Spectrum During the Dehydration Process of pasilla Chili Pepper

NASA Astrophysics Data System (ADS)

Zendejas-Leal, Blanca Estela; Barrientos-Sotelo, Víctor Rodrigo; Cano-Casas, Rogelio; Alvarado-Noguez, Margarita Lizeth; Hernández-Rosas, Juan; Cruz-Orea, Alfredo

2018-07-01

In this work, the optical absorption spectrum of peppers was monitored by phase-resolved photoacoustic spectroscopy during a dehydration process based on hot-air drying, yielding simultaneous information about changes in the exocarp and mesocarp. Our results show that between all of the dehydration processes of green Capsicum annuum L. variety pasilla peppers, only very small changes occur in the different phase angles, which has been correlated with the small changes in the exocarp thickness. The phase-resolved spectra of mesocarp show more clearly the evolution of the carotenoid compounds with respect to the optical absorption spectrum without phase resolving, due to the last spectrum having a band broadening in that region with more signals convolved. We have shown that not only do the ripened chili peppers produce new carotenoid compounds, but also we are probing that the dehydration process, beginning with the green stage, preserves the nutrimental content, similar to changes that occur in the natural ripening process.

In situ measurements of microbially-catalyzed nitrification and nitrate reduction rates in an ephemeral drainage channel receiving water from coalbed natural gas discharge, Powder River Basin, Wyoming, USA

USGS Publications Warehouse

Harris, S.H.; Smith, R.L.

2009-01-01

Nitrification and nitrate reduction were examined in an ephemeral drainage channel receiving discharge from coalbed natural gas (CBNG) production wells in the Powder River Basin, Wyoming. CBNG co-produced water typically contains dissolved inorganic nitrogen (DIN), primarily as ammonium. In this study, a substantial portion of discharged ammonium was oxidized within 50??m of downstream transport, but speciation was markedly influenced by diel fluctuations in dissolved oxygen (> 300????M). After 300??m of transport, 60% of the initial DIN load had been removed. The effect of benthic nitrogen-cycling processes on stream water chemistry was assessed at 2 locations within the stream channel using acrylic chambers to conduct short-term (2-6??h), in-stream incubations. The highest ambient DIN removal rates (2103????mol N m- 2 h- 1) were found at a location where ammonium concentrations > 350????M. This occurred during light incubations when oxygen concentrations were highest. Nitrification was occurring at the site, however, net accumulation of nitrate and nitrite accounted for < 12% of the ammonium consumed, indicating that other ammonium-consuming processes were also occurring. In dark incubations, nitrite and nitrate consumption were dominant processes, while ammonium was produced rather than consumed. At a downstream location nitrification was not a factor and changes in DIN removal rates were controlled by nitrate reduction, diel fluctuations in oxygen concentration, and availability of electron donor. This study indicates that short-term adaptation of stream channel processes can be effective for removing CBNG DIN loads given sufficient travel distances, but the long-term potential for nitrogen remobilization and nitrogen saturation remain to be determined.

Column Testing and 1D Reactive Transport Modeling to Evaluate Uranium Plume Persistence Processes

NASA Astrophysics Data System (ADS)

Johnson, R. H.; Morrison, S.; Morris, S.; Tigar, A.; Dam, W. L.; Dayvault, J.

2015-12-01

At many U.S. Department of Energy Office of Legacy Management sites, 100 year natural flushing was selected as a remedial option for groundwater uranium plumes. However, current data indicate that natural flushing is not occurring as quickly as expected and solid-phase and aqueous uranium concentrations are persistent. At the Grand Junction, Colorado office site, column testing was completed on core collected below an area where uranium mill tailings have been removed. The total uranium concentration in this core was 13.2 mg/kg and the column was flushed with laboratory-created water with no uranium and chemistry similar to the nearby Gunnison River. The core was flushed for a total of 91 pore volumes producing a maximum effluent uranium concentration of 6,110 μg/L at 2.1 pore volumes and a minimum uranium concentration of 36.2 μg/L at the final pore volume. These results indicate complex geochemical reactions at small pore volumes and a long tailing affect at greater pore volumes. Stop flow data indicate the occurrence of non-equilibrium processes that create uranium concentration rebound. These data confirm the potential for plume persistence, which is occurring at the field scale. 1D reactive transport modeling was completed using PHREEQC (geochemical model) and calibrated to the column test data manually and using PEST (inverse modeling calibration routine). Processes of sorption, dual porosity with diffusion, mineral dissolution, dispersion, and cation exchange were evaluated separately and in combination. The calibration results indicate that sorption and dual porosity are major processes in explaining the column test data. These processes are also supported by fission track photographs that show solid-phase uranium residing in less mobile pore spaces. These procedures provide valuable information on plume persistence and secondary source processes that may be used to better inform and evaluate remedial strategies, including natural flushing.

Pyrite cathode material for a thermal battery

NASA Astrophysics Data System (ADS)

Pemsler, J. P.; Litchfield, J. K.

1991-02-01

The present invention relates in general to a synthetic cathode material for a molten salt battery and, more particularly, to a process of providing and using synthetic pyrite for use as a cathode in a thermal battery. These batteries, which have been successfully used in a number of military applications, include iron disulfide cathode material obtained as benefacted or from natural occurring pyrite deposits, or as a byproduct of flotation concentrate from the processing of base or noble metal ores.

Detecting blast-induced infrasound in wind noise.

PubMed

Howard, Wheeler B; Dillion, Kevin L; Shields, F Douglas

2010-03-01

Current efforts seek to monitor and investigate such naturally occurring events as volcanic eruptions, hurricanes, bolides entering the atmosphere, earthquakes, and tsunamis by the infrasound they generate. Often, detection of the infrasound signal is limited by the masking effect of wind noise. This paper describes the use of a distributed array to detect infrasound signals from four atmospheric detonations at White Sands Missile Range in New Mexico, USA in 2006. Three of the blasts occurred during times of low wind noise and were easily observed with array processing techniques. One blast was obscured by high wind conditions. The results of signal processing are presented that allowed localization of the blast-induced signals in the presence of wind noise in the array response.

Electropulse treatment of water solution of humic substances in a layer iron granules in process of water treatment

NASA Astrophysics Data System (ADS)

Lobanova, G. L.; Yurmazova, T. A.; Shiyan, L. N.; Machekhina, K. I.

2016-02-01

The present work is a part of a continuations study of the physical and chemical processes complex in natural waters containing humic-type organic substances at the influence of pulsed electrical discharges in a layer of iron pellets. The study of humic substances processing in the iron granules layer by means of pulsed electric discharge for the purpose of water purification from organic compounds humic origin from natural water of the northern regions of Russia is relevant for the water treatment technologies. In case of molar humate sodium - iron ions (II) at the ratio 2:3, reduction of solution colour and chemical oxygen demand occur due to the humate sodium ions and iron (II) participation in oxidation-reduction reactions followed by coagulation insoluble compounds formation at a pH of 6.5. In order to achieve this molar ratio and the time of pulsed electric discharge, equal to 10 seconds is experimentally identified. The role of secondary processes that occur after disconnection of the discharge is shown. The time of contact in active erosion products with sodium humate, equal to 1 hour is established. During this time, the value of permanganate oxidation and iron concentration in solution achieves the value of maximum permissible concentrations and further contact time increase does not lead to the controlled parameters change.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Merkley, Eric D.; Sego, Landon H.; Lin, Andy

Adaptive processes in bacterial species can occur rapidly in laboratory culture, leading to genetic divergence between naturally occurring and laboratory-adapted strains. Differentiating wild and closely-related laboratory strains is clearly important for biodefense and bioforensics; however, DNA sequence data alone has thus far not provided a clear signature, perhaps due to lack of understanding of how diverse genome changes lead to adapted phenotypes. Protein abundance profiles from mass spectrometry-based proteomics analyses are a molecular measure of phenotype. Proteomics data contains sufficient information that powerful statistical methods can uncover signatures that distinguish wild strains of Yersinia pestis from laboratory-adapted strains.

Polarization dependent two-photon absorption spectroscopy on a naturally occurring biomarker (curcumin) in solution: A theoretical-experimental study

NASA Astrophysics Data System (ADS)

Tiburcio-Moreno, Jose A.; Alvarado-Gil, J. J.; Diaz, Carlos; Echevarria, Lorenzo; Hernández, Florencio E.

2013-09-01

We report on the theoretical-experimental analysis of the two-photon absorption (TPA) and two-photon circular-linear dichroism (TPCLD) spectra of (1E,6E)-1,7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione (curcumin) in Tetrahydrofuran (THF) solution. The measurement of the full TPA spectrum of this molecule reveals a maximum TPA cross-section at 740 nm, i.e. more than 10 times larger than the maximum reported in the literature at 800 nm for the application of curcumin in bioimaging. The TPCLD spectrum exposes the symmetry of the main excited-states involved in the two-photon excitation process. TD-DFT calculations support the experimental results. These outcomes are expected to expand the application of natural-occurring dyes in bioimaging.

Review of factors affecting recovery of freshwater stored in saline aquifers

USGS Publications Warehouse

Merritt, Michael L.

1989-01-01

A simulation analysis reported previously, and summarized herein, identified the effects of various geohydrologic and operational factors on recoverability of the injected water. Buoyancy stratification, downgradient advection, and hydrodynamic dispersion are the principal natural processes that reduce the amount of injected water that can be recovered. Buoyancy stratification is shown to depend on injection-zone permeability and the density contrast between injected and saline native water. Downgradient advection occurs as a result of natural or induced hydraulic gradients in the aquifer. Hydrodynamic dispersion reduces recovery efficiency by mixing some of the injected water with native saline aquifer water. In computer simulations, the relation of recovery efficiency to volume injected and its improvement during successive injection-recovery cycles was shown to depend on changes in the degree of hydrodynamic dispersion that occurs. Additional aspects of the subject are discussed.

Resolving disputes over science in natural resource agency decisionmaking

USGS Publications Warehouse

Ruell, Emily; Burkardt, Nina; Clark, Douglas R.

2010-01-01

Natural resource agencies make decisions involving public resources in which the public, by definition, have a stake. These resources are often finite. Thus, different viewpoints, interests, or beliefs may conflict when parties are perceived to be interdependent or one party is perceived to block or oppose other parties' use of a scarce resource. These confl icts may occur regard less of whether there are any real differences between the parties or whether one party's actions actually affect the other (Thomas 1992; Robbins 1994; Appelbaum et al. 1999). Conflicts are defined here as "a process of social interaction involving a struggle over claims to resources, power and status, beliefs, and other preferences and desires" (Appelbaum et al. 1999, 63). Such conflicts can occur at multiple stages or levels of decisionmaking and can be embedded within other conflicts.

Fungi as a source of natural coumarins production.

PubMed

Costa, Tania Maria; Tavares, Lorena Benathar Ballod; de Oliveira, Débora

2016-08-01

Natural coumarins and derivatives are compounds that occur naturally in several organisms (plant, bacteria, and fungi) consisting of fused benzene and α-pyrone rings. These compounds show high technological potential applications in agrochemical, food, pharmaceuticals, and cosmetics industries. Therefore, the need for bulk production of coumarins and the advancement of the chemical and pharmaceutical industries led to the development of synthetic coumarin. However, biotransformation process, synthetic bioengineering, metabolic engineering, and bioinformatics have proven effective in the production of natural products. Today, these biological systems are recognized as green chemistry innovation and business strategy. This review article aims to report the potential of fungi for synthesis of coumarin. These microorganisms are described as a source of natural products capable of synthesizing many bioactive metabolites. The features, classification, properties, and industrial applications of natural coumarins as well as new molecules obtained by basidiomycetes and ascomycetes fungi are reported in order to explore a topic not yet discussed in the scientific literature.

Peroxidase-mediated removal of a polychlorinated biphenyl using natural organic matter as the sole cosubstrate.

PubMed

Colosi, Lisa M; Burlingame, Daniel J; Huang, Qingguo; Weber, Walter J

2007-02-01

Natural organic matter (NOM) of hydroxylated aromatic character can undergo catalyst-mediated self-coupling reactions to form larger molecular aggregates. Indeed, such reactions are central to natural humification processes. Nonhydroxylated persistent aromatic contaminants such as polychlorinated biphenyls (PCBs) are, conversely, inert with respect to such reactions. It is here demonstrated however that significant coincidental coupling and removal of a representative aqueous-phase PCB occurs during horseradish peroxidase (HRP)-catalyzed oxidative coupling reactions of a representative aquatic NOM. Experiments with Suwannee River fulvic acid as a reactive cosubstrate indicate that 2,2'-dichlorobiphenyl (PCB-4) is covalently incorporated into aggregating NOM, likely through fortuitous cross-coupling reactions. To develop a better understanding of potential mechanisms by which the observed phenomenon occurs, two hydroxylated monomeric cosubstrates of known molecular structure, phenol and 4-methoxyphenol, were investigated as alternative cosubstrates. PCB-4 removal appears from these experiments to relate to certain molecular characteristics of the native cosubstrate molecule (reactivity with HRP, favorability for radical attack, and hydrophobicity) and its associated phenoxy radical (stability). The findings reveal potential pathways by which PCBs, and perhaps other polyaromatic contaminants, may be naturally transformed and detoxified in nature. The results further provide a foundation for development of enhanced-humification strategies for remediation of PCB-contaminated environmental systems.

A Polymorphism in the Processing Body Component Ge-1 Controls Resistance to a Naturally Occurring Rhabdovirus in Drosophila.

PubMed

Cao, Chuan; Magwire, Michael M; Bayer, Florian; Jiggins, Francis M

2016-01-01

Hosts encounter an ever-changing array of pathogens, so there is continual selection for novel ways to resist infection. A powerful way to understand how hosts evolve resistance is to identify the genes that cause variation in susceptibility to infection. Using high-resolution genetic mapping we have identified a naturally occurring polymorphism in a gene called Ge-1 that makes Drosophila melanogaster highly resistant to its natural pathogen Drosophila melanogaster sigma virus (DMelSV). By modifying the sequence of the gene in transgenic flies, we identified a 26 amino acid deletion in the serine-rich linker region of Ge-1 that is causing the resistance. Knocking down the expression of the susceptible allele leads to a decrease in viral titre in infected flies, indicating that Ge-1 is an existing restriction factor whose antiviral effects have been increased by the deletion. Ge-1 plays a central role in RNA degradation and the formation of processing bodies (P bodies). A key effector in antiviral immunity, the RNAi induced silencing complex (RISC), localises to P bodies, but we found that Ge-1-based resistance is not dependent on the small interfering RNA (siRNA) pathway. However, we found that Decapping protein 1 (DCP1) protects flies against sigma virus. This protein interacts with Ge-1 and commits mRNA for degradation by removing the 5' cap, suggesting that resistance may rely on this RNA degradation pathway. The serine-rich linker domain of Ge-1 has experienced strong selection during the evolution of Drosophila, suggesting that this gene may be under long-term selection by viruses. These findings demonstrate that studying naturally occurring polymorphisms that increase resistance to infections enables us to identify novel forms of antiviral defence, and support a pattern of major effect polymorphisms controlling resistance to viruses in Drosophila.

Training the Brain: Practical Applications of Neural Plasticity From the Intersection of Cognitive Neuroscience, Developmental Psychology, and Prevention Science

PubMed Central

Bryck, Richard L.; Fisher, Philip A.

2012-01-01

Prior researchers have shown that the brain has a remarkable ability for adapting to environmental changes. The positive effects of such neural plasticity include enhanced functioning in specific cognitive domains and shifts in cortical representation following naturally occurring cases of sensory deprivation; however, maladaptive changes in brain function and development owing to early developmental adversity and stress have also been well documented. Researchers examining enriched rearing environments in animals have revealed the potential for inducing positive brain plasticity effects and have helped to popularize methods for training the brain to reverse early brain deficits or to boost normal cognitive functioning. In this paper, two classes of empirically based methods of brain training in children are reviewed and critiqued: laboratory-based, mental process training paradigms and ecological interventions based upon neurocognitive conceptual models. Given the susceptibility of executive function disruption, special attention is paid to training programs that emphasize executive function enhancement. In addition, a third approach to brain training, aimed at tapping into compensatory processes, is postulated. Study results showing the effectiveness of this strategy in the field of neurorehabilitation and in terms of naturally occurring compensatory processing in human aging lend credence to the potential of this approach. PMID:21787037

Training the brain: practical applications of neural plasticity from the intersection of cognitive neuroscience, developmental psychology, and prevention science.

PubMed

Bryck, Richard L; Fisher, Philip A

2012-01-01

Prior researchers have shown that the brain has a remarkable ability for adapting to environmental changes. The positive effects of such neural plasticity include enhanced functioning in specific cognitive domains and shifts in cortical representation following naturally occurring cases of sensory deprivation; however, maladaptive changes in brain function and development owing to early developmental adversity and stress have also been well documented. Researchers examining enriched rearing environments in animals have revealed the potential for inducing positive brain plasticity effects and have helped to popularize methods for training the brain to reverse early brain deficits or to boost normal cognitive functioning. In this article, two classes of empirically based methods of brain training in children are reviewed and critiqued: laboratory-based, mental process training paradigms and ecological interventions based upon neurocognitive conceptual models. Given the susceptibility of executive function disruption, special attention is paid to training programs that emphasize executive function enhancement. In addition, a third approach to brain training, aimed at tapping into compensatory processes, is postulated. Study results showing the effectiveness of this strategy in the field of neurorehabilitation and in terms of naturally occurring compensatory processing in human aging lend credence to the potential of this approach. (PsycINFO Database Record (c) 2012 APA, all rights reserved).

Speech versus Song: Multiple Pitch-Sensitive Areas Revealed by a Naturally Occurring Musical Illusion

PubMed Central

Dick, Fred; Deutsch, Diana; Sereno, Marty

2013-01-01

It is normally obvious to listeners whether a human vocalization is intended to be heard as speech or song. However, the 2 signals are remarkably similar acoustically. A naturally occurring boundary case between speech and song has been discovered where a spoken phrase sounds as if it were sung when isolated and repeated. In the present study, an extensive search of audiobooks uncovered additional similar examples, which were contrasted with samples from the same corpus that do not sound like song, despite containing clear prosodic pitch contours. Using functional magnetic resonance imaging, we show that hearing these 2 closely matched stimuli is not associated with differences in response of early auditory areas. Rather, we find that a network of 8 regions, including the anterior superior temporal gyrus (STG) just anterior to Heschl's gyrus and the right midposterior STG, respond more strongly to speech perceived as song than to mere speech. This network overlaps a number of areas previously associated with pitch extraction and song production, confirming that phrases originally intended to be heard as speech can, under certain circumstances, be heard as song. Our results suggest that song processing compared with speech processing makes increased demands on pitch processing and auditory–motor integration. PMID:22314043

Naturally occurring 32Si and low-background silicon dark matter detectors

DOE PAGES

Orrell, John L.; Arnquist, Isaac J.; Bliss, Mary; ...

2018-02-10

Here, the naturally occurring radioisotope 32Si represents a potentially limiting background in future dark matter direct-detection experiments. We investigate sources of 32Si and the vectors by which it comes to reside in silicon crystals used for fabrication of radiation detectors. We infer that the 32Si concentration in commercial single-crystal silicon is likely variable, dependent upon the specific geologic and hydrologic history of the source (or sources) of silicon “ore” and the details of the silicon-refinement process. The silicon production industry is large, highly segmented by refining step, and multifaceted in terms of final product type, from which we conclude thatmore » production of 32Si-mitigated crystals requires both targeted silicon material selection and a dedicated refinement-through-crystal-production process. We review options for source material selection, including quartz from an underground source and silicon isotopically reduced in 32Si. To quantitatively evaluate the 32Si content in silicon metal and precursor materials, we propose analytic methods employing chemical processing and radiometric measurements. Ultimately, it appears feasible to produce silicon detectors with low levels of 32Si, though significant assay method development is required to validate this claim and thereby enable a quality assurance program during an actual controlled silicon-detector production cycle.« less

Naturally occurring 32Si and low-background silicon dark matter detectors

NASA Astrophysics Data System (ADS)

Orrell, John L.; Arnquist, Isaac J.; Bliss, Mary; Bunker, Raymond; Finch, Zachary S.

2018-05-01

The naturally occurring radioisotope 32Si represents a potentially limiting background in future dark matter direct-detection experiments. We investigate sources of 32Si and the vectors by which it comes to reside in silicon crystals used for fabrication of radiation detectors. We infer that the 32Si concentration in commercial single-crystal silicon is likely variable, dependent upon the specific geologic and hydrologic history of the source (or sources) of silicon "ore" and the details of the silicon-refinement process. The silicon production industry is large, highly segmented by refining step, and multifaceted in terms of final product type, from which we conclude that production of 32Si-mitigated crystals requires both targeted silicon material selection and a dedicated refinement-through-crystal-production process. We review options for source material selection, including quartz from an underground source and silicon isotopically reduced in 32Si. To quantitatively evaluate the 32Si content in silicon metal and precursor materials, we propose analytic methods employing chemical processing and radiometric measurements. Ultimately, it appears feasible to produce silicon detectors with low levels of 32Si, though significant assay method development is required to validate this claim and thereby enable a quality assurance program during an actual controlled silicon-detector production cycle.

Naturally occurring 32Si and low-background silicon dark matter detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Orrell, John L.; Arnquist, Isaac J.; Bliss, Mary

Here, the naturally occurring radioisotope 32Si represents a potentially limiting background in future dark matter direct-detection experiments. We investigate sources of 32Si and the vectors by which it comes to reside in silicon crystals used for fabrication of radiation detectors. We infer that the 32Si concentration in commercial single-crystal silicon is likely variable, dependent upon the specific geologic and hydrologic history of the source (or sources) of silicon “ore” and the details of the silicon-refinement process. The silicon production industry is large, highly segmented by refining step, and multifaceted in terms of final product type, from which we conclude thatmore » production of 32Si-mitigated crystals requires both targeted silicon material selection and a dedicated refinement-through-crystal-production process. We review options for source material selection, including quartz from an underground source and silicon isotopically reduced in 32Si. To quantitatively evaluate the 32Si content in silicon metal and precursor materials, we propose analytic methods employing chemical processing and radiometric measurements. Ultimately, it appears feasible to produce silicon detectors with low levels of 32Si, though significant assay method development is required to validate this claim and thereby enable a quality assurance program during an actual controlled silicon-detector production cycle.« less

Naturally occurring 32 Si and low-background silicon dark matter detectors

DOE Office of Scientific and Technical Information (OSTI.GOV)

Orrell, John L.; Arnquist, Isaac J.; Bliss, Mary

The naturally occurring radioisotope Si-32 represents a potentially limiting background in future dark matter direct-detection experiments. We investigate sources of Si-32 and the vectors by which it comes to reside in silicon crystals used for fabrication of radiation detectors. We infer that the Si-32 concentration in commercial single-crystal silicon is likely variable, dependent upon the specific geologic and hydrologic history of the source (or sources) of silicon “ore” and the details of the silicon-refinement process. The silicon production industry is large, highly segmented by refining step, and multifaceted in terms of final product type, from which we conclude that productionmore » of Si-32-mitigated crystals requires both targeted silicon material selection and a dedicated refinement-through-crystal-production process. We review options for source material selection, including quartz from an underground source and silicon isotopically reduced in Si-32. To quantitatively evaluate the Si-32 content in silicon metal and precursor materials, we propose analytic methods employing chemical processing and radiometric measurements. Ultimately, it appears feasible to produce silicon-based detectors with low levels of Si-32, though significant assay method development is required to validate this claim and thereby enable a quality assurance program during an actual controlled silicon-detector production cycle.« less

Radiation-induced effects on the mechanical properties of natural ZrSiO4: double cascade-overlap damage accumulation

NASA Astrophysics Data System (ADS)

Beirau, Tobias; Nix, William D.; Pöllmann, Herbert; Ewing, Rodney C.

2018-05-01

Several different models are known to describe the structure-dependent radiation-induced damage accumulation process in materials (e.g. Gibbons Proc IEEE 60:1062-1096, 1972; Weber Nuc Instr Met Phys Res B 166-167:98-106, 2000). In the literature, two different models of damage accumulation due to α-decay events in natural ZrSiO4 (zircon) have been described. The direct impact damage accumulation model is based on amorphization occurring directly within the collision cascade. However, the double cascade-overlap damage accumulation model predicts that amorphization will only occur due to the overlap of disordered domains within the cascade. By analyzing the dose-dependent evolution of mechanical properties (i.e., Poisson's ratios, compliance constants, elastic modulus, and hardness) as a measure of the increasing amorphization, we provide support for the double cascade-overlap damage accumulation model. We found no evidence to support the direct impact damage accumulation model. Additionally, the amount of radiation damage could be related to an anisotropic-to-isotropic transition of the Poisson's ratio for stress along and perpendicular to the four-fold c-axis and of the related compliance constants of natural U- and Th-bearing zircon. The isotropification occurs in the dose range between 3.1 × and 6.3 × 1018 α-decays/g.

Radiation-induced effects on the mechanical properties of natural ZrSiO4: double cascade-overlap damage accumulation

NASA Astrophysics Data System (ADS)

Beirau, Tobias; Nix, William D.; Pöllmann, Herbert; Ewing, Rodney C.

2017-11-01

Several different models are known to describe the structure-dependent radiation-induced damage accumulation process in materials (e.g. Gibbons Proc IEEE 60:1062-1096, 1972; Weber Nuc Instr Met Phys Res B 166-167:98-106, 2000). In the literature, two different models of damage accumulation due to α-decay events in natural ZrSiO4 (zircon) have been described. The direct impact damage accumulation model is based on amorphization occurring directly within the collision cascade. However, the double cascade-overlap damage accumulation model predicts that amorphization will only occur due to the overlap of disordered domains within the cascade. By analyzing the dose-dependent evolution of mechanical properties (i.e., Poisson's ratios, compliance constants, elastic modulus, and hardness) as a measure of the increasing amorphization, we provide support for the double cascade-overlap damage accumulation model. We found no evidence to support the direct impact damage accumulation model. Additionally, the amount of radiation damage could be related to an anisotropic-to-isotropic transition of the Poisson's ratio for stress along and perpendicular to the four-fold c-axis and of the related compliance constants of natural U- and Th-bearing zircon. The isotropification occurs in the dose range between 3.1 × and 6.3 × 1018 α-decays/g.

Local dispersal promotes biodiversity in a real-life game of rock-paper-scissors

NASA Astrophysics Data System (ADS)

Kerr, Benjamin; Riley, Margaret A.; Feldman, Marcus W.; Bohannan, Brendan J. M.

2002-07-01

One of the central aims of ecology is to identify mechanisms that maintain biodiversity. Numerous theoretical models have shown that competing species can coexist if ecological processes such as dispersal, movement, and interaction occur over small spatial scales. In particular, this may be the case for non-transitive communities, that is, those without strict competitive hierarchies. The classic non-transitive system involves a community of three competing species satisfying a relationship similar to the children's game rock-paper-scissors, where rock crushes scissors, scissors cuts paper, and paper covers rock. Such relationships have been demonstrated in several natural systems. Some models predict that local interaction and dispersal are sufficient to ensure coexistence of all three species in such a community, whereas diversity is lost when ecological processes occur over larger scales. Here, we test these predictions empirically using a non-transitive model community containing three populations of Escherichia coli. We find that diversity is rapidly lost in our experimental community when dispersal and interaction occur over relatively large spatial scales, whereas all populations coexist when ecological processes are localized.

An Overview of Snow Photochemistry: Evidence, Mechanisms and Impacts

NASA Technical Reports Server (NTRS)

Grannas, A. M.; Jones, A. E.; Dibb, J.; Ammann, M.; Anastasio, C.; Beine, H. J.; Bergin, M.; Bottenheim, J.; Boxe, C. S.; Carver, G.;

Rollover in volcanic crater lakes: a possible cause for Lake Nyos type disasters

NASA Astrophysics Data System (ADS)

Rice, A.

2000-04-01

Seemingly stably stratified fluids, that is a heavier layer of fluid underlying an upper layer of lighter fluid, can overturn if there is a heat flux through the system. Such events are termed ;rollover; in the engineering literature (occurring for instance in liquid natural gas tanks). They take place as well in lakes and ponds. In all such cases, the stratification starts off with the heavier, more dense fluid underlying lighter. Convection driven mixing at the stratification interface (due to the heat flux) as well as other processes serves to minimize with time the stabilizing density differences, which may eventually cause the stratification to invert. If gas has been contained under pressure in the lower layer, this gas may explosively vent from the fluid as it suddenly rises to the top such as occurs in liquid natural gas tanks where rollover is a hazard. These processes are quantifiable and are applied here to various scenarios that might refer to volcanic crater lakes whose lower layers are charged with volatiles. Provided herein are some examples of calculated conditions and calculated time of evolution leading to rollover with attendant release of gases from supersaturated ascending fluids. These calculations suggest rollover could occur in volcanic lakes. The August 1986 gas release at Lake Nyos is employed as an example. These estimates were made taking note that water is commonly supersaturated in CO2

A Drop through Time

ERIC Educational Resources Information Center

Vowell, Julie; Phillips, Marianne

2007-01-01

Did you know that the water you use today is the same water that was used millions of years ago? How is this possible? Water is continuously replenished through a naturally occurring process known as the water cycle. To help students learn about this important concept, an eight-day unit was created for fifth-grade students to explore the water…

The Incorporation of Poverty into Adult Identity over Time: Implications for Adult Education

ERIC Educational Resources Information Center

Brown, Byron A.

2005-01-01

For many years, poverty has dominated international headlines as a global condition. In some countries, poverty has become a chronic socioeconomic problem. This qualitative study explored the incorporation process of poverty into adult identity and assessed the nature of the learning that occurred. Destitute adults in Botswana were chosen and used…

Harnessing the Power of Play: Opportunities for Children with Autism Spectrum Disorders

ERIC Educational Resources Information Center

Mastrangelo, Sonia

2009-01-01

Play is a complex phenomenon that occurs naturally for most children; they move through the various stages of play development and are able to add complexity, imagination, and creativity to their thought processes and actions. However, for many children with autism spectrum disorders (ASD), the various stages of play never truly develop, or occur…

Effects of Ageism on Individual and Health Care Providers' Responses to Healthy Aging.

ERIC Educational Resources Information Center

Grant, Lynda D.

1996-01-01

Reviews literature to support the contention that misconceptions about the aging process have a detrimental effect on healthy aging. Seeks to demonstrate how stereotyping can affect the shape and nature of programs for elderly people. Argues that for long-lasting change to occur, service providers need to target these negative attitudes in…

Cumulative Repetition Effects across Multiple Readings of a Word: Evidence from Eye Movements

ERIC Educational Resources Information Center

Kamienkowski, Juan E.; Carbajal, M. Julia; Bianchi, Bruno; Sigman, Mariano; Shalom, Diego E.

2018-01-01

When a word is read more than once, reading time generally decreases in the successive occurrences. This Repetition Effect has been used to study word encoding and memory processes in a variety of experimental measures. We studied naturally occurring repetitions of words within normal texts (stories of around 3,000 words). Using linear mixed…

EFFECTS OF REVERSE OSMOSIS ISOLATION ON REACTIVITY OF NATURALLY OCCURRING DISSOLVED ORGANIC MATTER IN PHYSICOCHEMICAL PROCESSES. (R828045)

EPA Science Inventory

A field reverse osmosis system was used to isolate dissolved organic matter (DOM) from two lacustrine and two riverine surface water sources. The rejection of DOM was on the order of 99% and did not vary significantly with pressure. A simple mass balance model using a single m...

Physiological Factors in Adult Learning and Instruction. Research to Practice Series.

ERIC Educational Resources Information Center

Verner, Coolie; Davison, Catherine V.

The physiological condition of the adult learner as related to his learning capability is discussed. The design of the instructional process, the selection of learning tasks, the rate at which instruction occurs, and the nature of the instructional setting may all be modified by the instructor to accomodate the variable physiological conditions of…

Starbursts and their dynamics

NASA Technical Reports Server (NTRS)

Norman, Colin

1987-01-01

Detailed mechanisms associated with dynamical process occurring in starburst galaxies are considered including the role of bars, waves, mergers, sinking satellites, self gravitating gas and bulge heating. The current understanding of starburst galaxies both observational and theoretical is placed in the context of theories of galaxy formations, Hubble sequence evolution, starbursts and activity, and the nature of quasar absorption lines.

Semantic Structure of Classroom Discourse Concerning Proof and Proving in High School Mathematics

ERIC Educational Resources Information Center

Ugurel, Isikhan; Boz-Yaman, Burcak

2017-01-01

This study tries to identify high school students' knowledge about the concept of proof, based on classroom discussion. The processes of discourses, both natural and prompted, are studied as they occur between students and teachers. The study employs discourse analysis as the qualitative research framework. Participants are 13 Science High School…

Teachers' Language in Interactions: An Exploratory Examination of Mental State Talk in Early Childhood Education Classrooms

ERIC Educational Resources Information Center

King, Elizabeth; La Paro, Karen

2015-01-01

Research Findings: This study examined 34 Head Start teachers' use of four categories of mental state talk (verbalizations of mental processes using emotion terms, cognition terms, desire terms, and perception terms) during naturally occurring classroom interactions. Transcriptions from classroom videos were coded for mental state talk…

Nature's Electric Potential: A Systematic Review of the Role of Bioelectricity in Wound Healing and Regenerative Processes in Animals, Humans, and Plants.

PubMed

Tyler, Sheena E B

2017-01-01

Natural endogenous voltage gradients not only predict and correlate with growth and development but also drive wound healing and regeneration processes. This review summarizes the existing literature for the nature, sources, and transmission of information-bearing bioelectric signals involved in controlling wound healing and regeneration in animals, humans, and plants. It emerges that some bioelectric characteristics occur ubiquitously in a range of animal and plant species. However, the limits of similarities are probed to give a realistic assessment of future areas to be explored. Major gaps remain in our knowledge of the mechanistic basis for these processes, on which regenerative therapies ultimately depend. In relation to this, it is concluded that the mapping of voltage patterns and the processes generating them is a promising future research focus, to probe three aspects: the role of wound/regeneration currents in relation to morphology; the role of endogenous flux changes in driving wound healing and regeneration; and the mapping of patterns in organisms of extreme longevity, in contrast with the aberrant voltage patterns underlying impaired healing, to inform interventions aimed at restoring them.

Nature's Electric Potential: A Systematic Review of the Role of Bioelectricity in Wound Healing and Regenerative Processes in Animals, Humans, and Plants

PubMed Central

Tyler, Sheena E. B.

2017-01-01

Natural endogenous voltage gradients not only predict and correlate with growth and development but also drive wound healing and regeneration processes. This review summarizes the existing literature for the nature, sources, and transmission of information-bearing bioelectric signals involved in controlling wound healing and regeneration in animals, humans, and plants. It emerges that some bioelectric characteristics occur ubiquitously in a range of animal and plant species. However, the limits of similarities are probed to give a realistic assessment of future areas to be explored. Major gaps remain in our knowledge of the mechanistic basis for these processes, on which regenerative therapies ultimately depend. In relation to this, it is concluded that the mapping of voltage patterns and the processes generating them is a promising future research focus, to probe three aspects: the role of wound/regeneration currents in relation to morphology; the role of endogenous flux changes in driving wound healing and regeneration; and the mapping of patterns in organisms of extreme longevity, in contrast with the aberrant voltage patterns underlying impaired healing, to inform interventions aimed at restoring them. PMID:28928669

Alpha-emitting nuclides in the marine environment

NASA Astrophysics Data System (ADS)

Pentreath, R. J.

1984-06-01

The occurrence of alpha-emitting nuclides and their daughter products in the marine environment continues to be a subject of study for many reasons. Those nuclides which occur naturally, in the uranium, thorium and actinium series, are of interest because of their value in determining the rates of geological and geochemical processes in the oceans. Studies of them address such problems as the determination of rates of transfer of particulate matter, deposition rates, bioturbation rates, and so on. Two of the natural alpha-series nuclides in which a different interest has been expressed are 210Po and 226Ra, because their concentrations in marine organisms are such that they contribute to a significant fraction of the background dose rates sustained both by the organisms themselves and by consumers of marine fish and shellfish. To this pool of naturally-occurring nuclides, human activities have added the transuranium nuclides, both from the atmospheric testing of nuclear devices and from the authorized discharges of radioactive wastes into coastal waters and the deep sea. Studies have therefore been made to understand the chemistry of these radionuclides in sea water, their association with sedimentary materials, and their accumulation by marine organisms, the last of these being of particular interest because the transuranics are essentially "novel" elements to the marine fauna and flora. The need to predict the long-term behaviour of these nuclides has, in turn, stimulated research on those naturally-occurring nuclides which may behave in a similar manner.

Natural asynchronies in audiovisual communication signals regulate neuronal multisensory interactions in voice-sensitive cortex

PubMed Central

Perrodin, Catherine; Kayser, Christoph; Logothetis, Nikos K.; Petkov, Christopher I.

2015-01-01

When social animals communicate, the onset of informative content in one modality varies considerably relative to the other, such as when visual orofacial movements precede a vocalization. These naturally occurring asynchronies do not disrupt intelligibility or perceptual coherence. However, they occur on time scales where they likely affect integrative neuronal activity in ways that have remained unclear, especially for hierarchically downstream regions in which neurons exhibit temporally imprecise but highly selective responses to communication signals. To address this, we exploited naturally occurring face- and voice-onset asynchronies in primate vocalizations. Using these as stimuli we recorded cortical oscillations and neuronal spiking responses from functional MRI (fMRI)-localized voice-sensitive cortex in the anterior temporal lobe of macaques. We show that the onset of the visual face stimulus resets the phase of low-frequency oscillations, and that the face–voice asynchrony affects the prominence of two key types of neuronal multisensory responses: enhancement or suppression. Our findings show a three-way association between temporal delays in audiovisual communication signals, phase-resetting of ongoing oscillations, and the sign of multisensory responses. The results reveal how natural onset asynchronies in cross-sensory inputs regulate network oscillations and neuronal excitability in the voice-sensitive cortex of macaques, a suggested animal model for human voice areas. These findings also advance predictions on the impact of multisensory input on neuronal processes in face areas and other brain regions. PMID:25535356

Space processing experimental apparatus - A survey

NASA Technical Reports Server (NTRS)

Siebel, M. P.

1977-01-01

The processing of materials in a low-g environment was started approximately 10 years ago. This article surveys the apparatus developed during that period. A low-g environment occurs naturally in a free-flying spacecraft (e.g., in manned flights such as Apollo, Skylab, and ASTP); low-g conditions also occur in other free-falling bodies such as sounding rockets and drop tower capsules. Apparatus has been developed for all these craft. Most of the apparatus described serves to melt and resolidify materials in low g; the material may be contained or, by virtue of the environment, freely floating. Other apparatus for separation of intimately mixed components or species is also described. A general conclusion is drawn that the apparatus addresses only a few of the possibilities available, is still at the experimental stage, and is of laboratory scale. It is predicted that processes showing promise will be scaled up to derive economic advantages in the Shuttle era of space flight.

Effects of human-induced alteration of groundwater flow on concentrations of naturally-occurring trace elements at water-supply wells

USGS Publications Warehouse

Ayotte, J.D.; Szabo, Z.; Focazio, M.J.; Eberts, S.M.

2011-01-01

The effects of human-induced alteration of groundwater flow patterns on concentrations of naturally-occurring trace elements were examined in five hydrologically distinct aquifer systems in the USA. Although naturally occurring, these trace elements can exceed concentrations that are considered harmful to human health. The results show that pumping-induced hydraulic gradient changes and artificial connection of aquifers by well screens can mix chemically distinct groundwater. Chemical reactions between these mixed groundwaters and solid aquifer materials can result in the mobilization of trace elements such as U, As and Ra, with subsequent transport to water-supply wells. For example, in the High Plains aquifer near York, Nebraska, mixing of shallow, oxygenated, lower-pH water from an unconfined aquifer with deeper, confined, anoxic, higher-pH water is facilitated by wells screened across both aquifers. The resulting higher-O2, lower-pH mixed groundwater facilitated the mobilization of U from solid aquifer materials, and dissolved U concentrations were observed to increase significantly in nearby supply wells. Similar instances of trace element mobilization due to human-induced mixing of groundwaters were documented in: (1) the Floridan aquifer system near Tampa, Florida (As and U), (2) Paleozoic sedimentary aquifers in eastern Wisconsin (As), (3) the basin-fill aquifer underlying the California Central Valley near Modesto (U), and (4) Coastal Plain aquifers of New Jersey (Ra). Adverse water-quality impacts attributed to human activities are commonly assumed to be related solely to the release of the various anthropogenic contaminants to the environment. The results show that human activities including various land uses, well drilling, and pumping rates and volumes can adversely impact the quality of water in supply wells, when associated with naturally-occurring trace elements in aquifer materials. This occurs by causing subtle but significant changes in geochemistry and associated trace element mobilization as well as enhancing advective transport processes.

Statistical Patterns in Natural Lightning

NASA Astrophysics Data System (ADS)

Zoghzoghy, F. G.; Cohen, M.; Said, R.; Inan, U. S.

2011-12-01

Every day millions of lightning flashes occur around the globe but the understanding of this natural phenomenon is still lacking. Fundamentally, lightning is nature's way of destroying charge separation in clouds and restoring electric neutrality. Thus, statistical patterns of lightning activity indicate the scope of these electric discharges and offer a surrogate measure of timescales for charge buildup in thunderclouds. We present a statistical method to investigate spatio-temporal correlations among lightning flashes using National Lightning Detection Network (NLDN) stroke data. By monitoring the distribution of lightning activity, we can observe the charging and discharging processes in a given thunderstorm. In particular, within a given storm, the flashes do not occur as a memoryless random process. We introduce the No Flash Zone (NFZ) which results from the suppressed probability of two consecutive neighboring flashes. This effect lasts for tens of seconds and can extend up to 15 km around the location of the initial flash, decaying with time. This suppression effect may be a function of variables such as storm location, storm phase, and stroke peak current. We develop a clustering algorithm, Storm-Locator, which groups strokes into flashes, storm cells, and thunderstorms, and enables us to study lightning and the NFZ in different geographical regions, and for different storms. The recursive algorithm also helps monitor the interaction among spatially displaced storm cells, and can provide more insight into the spatial and temporal impacts of lightning discharges.

Biopolymer-based thermoplastic mixture for producing solid biodegradable shaped bodies and its photo degradation stability

NASA Astrophysics Data System (ADS)

Sulong, Nurulsaidatulsyida; Rus, Anika Zafiah M.

2013-12-01

In recent years, biopolymers with controllable lifetimes have become increasingly important for many applications in the areas of agriculture, biomedical implants and drug release, forestry, wild life conservation and waste management. Natural oils are considered to be the most important class of renewable sources. They can be obtained from naturally occurring plants, such as sunflower, cotton, linseed and palm oil. In Malaysia, palm oil is an inexpensive and commodity material. Biopolymer produced from palm oil (Bio-VOP) is a naturally occurring biodegradable polymer and readily available from agriculture. For packaging use however, Bio-VOP is not thermoplastic and its granular form is unsuitable for most uses in the plastics industry, mainly due to processing difficulties during extrusion or injection moulding. Thus, research workers have developed several methods to blend Bio-VOP appropriately for industrial uses. In particular, injections moulding processes, graft copolymerisation, and preparation of blends with thermoplastic polymers have been studied to produce solid biodegradable shaped bodies. HDPE was chosen as commercial thermoplastic materials and was added with 10% Bio-VOP for the preparation of solid biodegradable shaped bodies named as HD-VOP. The UV light exposure of HD-VOP at 12 minutes upon gives the highest strength of this material that is 17.6 MPa. The morphological structure of HD-VOP shows dwi structure surface fracture which is brittle and ductile properties.

Northeast Artificial Intelligence Consortium (NAIC). Volume 15. Strategies for Coupling Symbolic and Numerical Computation in Knowledge Base Systems

DTIC Science & Technology

1990-12-01

Implementation of Coupled System 18 15.4. CASE STUDIES & IMPLEMENTATION EXAMPLES 24 15.4.1. The Case Studies of Coupled System 24 15.4.2. Example: Coupled System...occurs during specific phases of the problem-solving process. By decomposing the coupling process into its component layers we effectively study the nature...by the qualitative model, appropriate mathematical model is invoked. 5) The results are verified. If successful, stop. Else go to (2) and use an

Rethinking the process of detrainment: jets in obstructed natural flows

NASA Astrophysics Data System (ADS)

Mossa, Michele; de Serio, Francesca

2016-12-01

A thorough understanding of the mixing and diffusion of turbulent jets released in porous obstructions is still lacking in literature. This issue is undoubtedly of interest because it is not strictly limited to vegetated flows, but also includes outflows which come from different sources and which spread among oyster or wind farms, as well as aerial pesticide treatments sprayed onto orchards. The aim of the present research is to analyze this process from a theoretical point of view. Specifically, by examining the entrainment coefficient, it is deduced that the presence of a canopy prevents a momentum jet from having an entrainment process, but rather promotes its detrainment. In nature, detrainment is usually associated with buoyancy-driven flows, such as plumes or density currents flowing in a stratified environment. The present study proves that detrainment occurs also when a momentum-driven jet is issued in a not-stratified obstructed current, such as a vegetated flow.

Seasonal Variability in Vadose zone biodegradation at a crude oil pipeline rupture site

USGS Publications Warehouse

Sihota, Natasha J.; Trost, Jared J.; Bekins, Barbara; Berg, Andrew M.; Delin, Geoffrey N.; Mason, Brent E.; Warren, Ean; Mayer, K. Ulrich

2016-01-01

Understanding seasonal changes in natural attenuation processes is critical for evaluating source-zone longevity and informing management decisions. The seasonal variations of natural attenuation were investigated through measurements of surficial CO2 effluxes, shallow soil CO2 radiocarbon contents, subsurface gas concentrations, soil temperature, and volumetric water contents during a 2-yr period. Surficial CO2 effluxes varied seasonally, with peak values of total soil respiration (TSR) occurring in the late spring and summer. Efflux and radiocarbon data indicated that the fractional contributions of natural soil respiration (NSR) and contaminant soil respiration (CSR) to TSR varied seasonally. The NSR dominated in the spring and summer, and CSR dominated in the fall and winter. Subsurface gas concentrations also varied seasonally, with peak values of CO2 and CH4 occurring in the fall and winter. Vadose zone temperatures and subsurface CO2 concentrations revealed a correlation between contaminant respiration and temperature. A time lag of 5 to 7 mo between peak subsurface CO2 concentrations and peak surface efflux is consistent with travel-time estimates for subsurface gas migration. Periods of frozen soils coincided with depressed surface CO2 effluxes and elevated CO2 concentrations, pointing to the temporary presence of an ice layer that inhibited gas transport. Quantitative reactive transport simulations demonstrated aspects of the conceptual model developed from field measurements. Overall, results indicated that source-zone natural attenuation (SZNA) rates and gas transport processes varied seasonally and that the average annual SZNA rate estimated from periodic surface efflux measurements is 60% lower than rates determined from measurements during the summer.

Investigation of Natural Radioactivity in a Monazite Processing Plant in Japan.

PubMed

Iwaoka, Kazuki; Yajima, Kazuaki; Suzuki, Toshikazu; Yonehara, Hidenori; Hosoda, Masahiro; Tokonami, Shinji; Kanda, Reiko

2017-09-01

Monazite is a naturally occurring radioactive material that is processed for use in a variety of domestic applications. At present, there is little information available on potential radiation doses experienced by people working with monazite. The ambient dose rate and activity concentration of natural radionuclides in raw materials, products, and dust in work sites as well as the Rn and Rn concentrations in work sites were measured in a monazite processing plant in Japan. Dose estimations for plant workers were also conducted. The activity concentration of the U series in raw materials and products for the monazite processing plant was found to be higher than the relevant values described in the International Atomic Energy Agency Safety Standards. The ambient dose rates in the raw material yard were higher than those in other work sites. Moreover, the activity concentrations of dust in the milling site were higher than those in other work sites. The Rn concentrations in all work sites were almost the same as those in regular indoor environments in Japan. The Rn concentrations in all work sites were much higher than those in regular indoor environments in Japan. The maximum value of the effective dose for workers was 0.62 mSv y, which is lower than the reference level range (1-20 mSv y) for abnormally high levels of natural background radiation published in the International Commission of Radiological Protection Publication 103.

Comprehensive investigation of tobacco leaves during natural early senescence via multi-platform metabolomics analyses

NASA Astrophysics Data System (ADS)

Li, Lili; Zhao, Jieyu; Zhao, Yanni; Lu, Xin; Zhou, Zhihui; Zhao, Chunxia; Xu, Guowang

2016-11-01

Senescence is the final stage of leaf growth and development. Many different physiological activities occur during this process. A comprehensive metabolomics analysis of tobacco middle leaves at 5 different developmental stages was implemented through multi-platform methods based on liquid chromatography, capillary electrophoresis and gas chromatography coupled with mass spectrometry. In total, 412 metabolites were identified, including pigments, sterols, lipids, amino acids, polyamines, sugars and secondary metabolites. Dramatic metabolic changes were observed. Firstly, membrane degradation and chlorophyll down-regulation occurred after the 50% flower bud stage. Levels of major membrane lipids decreased, including those of the glycolipids in chloroplast thylakoids and phospholipids in membrane envelopes. Clear decreases in free sterols and acylated sterol glucosides were detected along with the accumulation of sterol esters. The accumulation of alkaloids was found. The amino acid levels were significantly decreased, particularly those of N-rich amino acids (glutamine and asparagine), thus reflecting N translocation. Subsequently, the antioxidant system was activated. Sugar alcohols and polyphenols accumulated when the lower leaves turned yellow. These results comprehensively revealed the metabolic changes that occur during tobacco leaf development and senescence under natural conditions.

Evolution of drop size distribution in natural rain

NASA Astrophysics Data System (ADS)

D'Adderio, Leo Pio; Porcù, Federico; Tokay, Ali

2018-02-01

Both numerical modeling and laboratory experiments document the possibility of a raindrop size distribution (DSD) to evolve to an equilibrium stage (EDSD), where all the principal processes occur at steady rates. The aim of this work is to observe the temporal behavior of the DSD and to directly investigate the conditions favorable to the onset of the EDSD in natural rain. We exploited a large disdrometer dataset collected in the framework of the Ground Validation activities related to the NASA Global Precipitation Measurement mission. More than 200,000 one-minute data of two-dimensional video disdrometer (2DVD) are collected over USA to represent a wide range of precipitation types. The original data are averaged over 2 min and an automatic algorithm is used on a selected subset to identify samples with EDSD. Results show that the EDSD occurs mainly in convective events and lasts for very short time intervals (2 to 4 min). It is more frequent for rain rate between 20 and 40 mm h- 1 and it mostly occurs during sharp increase of precipitation rates.

The tearing mode locking-unlocking mechanism to an external resonant field in EXTRAP T2R

NASA Astrophysics Data System (ADS)

Frassinetti, L.; Fridström, R.; Menmuir, S.; Brunsell, P. R.

2014-10-01

The tearing mode (TM) locking and unlocking process due to an external resonant magnetic perturbation (RMP) is experimentally studied in EXTRAP T2R. The RMP produces a reduction of the natural TM velocity and ultimately the TM locking if a threshold in the RMP amplitude is exceeded. During the braking process, the TM slows down via a mechanism composed of deceleration and acceleration phases. During the acceleration phases, the TM can reach velocities higher than the natural velocity. Once the TM locking occurs, the RMP must be reduced to a small amplitude to obtain the TM unlocking, showing that the unlocking threshold is significantly smaller than the locking threshold and that the process is characterized by hysteresis. Experimental results are in qualitative agreement with a model that describes the locking-unlocking process via the balance of the electromagnetic torque produced by the RMP that acts to brake the TM and the viscous torque that tends to re-establish the unperturbed velocity.

Dispersal of micro-organisms in commercial defeathering systems.

PubMed

Allen, V M; Tinker, D B; Hinton, M H; Wathes, C M

2003-03-01

1. The extent of cross contamination between carcases and the dispersal of micro-organisms to the environs during defeathering was measured in a commercial processing plant. 2. Defeathering reduced the numbers of a marker organism, a nalidixic acid-resistant strain of Escherichia coli K12, on inoculated carcases but dispersed the organism on to preceding and following carcases. 3. The pattern of microbial dispersal during defeathering was similar for naturally occurring bacteria on the carcase, for example, total aerobic counts and counts of presumptive coliforms, suggesting that the marker organism mimics the natural situation realistically. 4. The majority of feathers, together with micro-organisms, were removed during the first 10 s of the defeathering process, which was completed in 45 s, indicating that control measures to minimise cross contamination would be most effective if applied in the early stages of the process. 5. The method of defeathering used by the machine influenced the pattern of microbial dispersal and the extent of cross contamination to other carcases on the same processing line.

Behaviour and fluxes of natural radionuclides in the production process of a phosphoric acid plant.

PubMed

Bolívar, J P; Martín, J E; García-Tenorio, R; Pérez-Moreno, J P; Mas, J L

2009-02-01

In recent years there has been an increasing awareness of the occupational and public hazards of the radiological impact of non-nuclear industries which process materials containing naturally occurring radionuclides. These include the industries devoted to the production of phosphoric acid by treating sedimentary phosphate rocks enriched in radionuclides from the uranium series. With the aim of evaluating the radiological impact of a phosphoric acid factory located in the south-western Spain, the distribution and levels of radionuclides in the materials involved in its production process have been analysed. In this way, it is possible to asses the flows of radionuclides at each step and to locate those points where a possible radionuclide accumulation could be produced. A set of samples collected along the whole production process were analysed to determine their radionuclide content by both alpha-particle and gamma spectrometry techniques. The radionuclide fractionation steps and enrichment sources have been located, allowing the establishment of their mass (activity) balances per year.

Isotopic inferences of ancient biochemistries - Carbon, sulfur, hydrogen, and nitrogen

NASA Technical Reports Server (NTRS)

Schidlowski, M.; Hayes, J. M.; Kaplan, I. R.

1983-01-01

In processes of biological incorporation and subsequent biochemical processing sizable isotope effects occur as a result of both thermodynamic and kinetic fractionations which take place during metabolic and biosynthetic reactions. In this chapter a review is provided of earlier work and recent studies on isotope fractionations in the biogeochemical cycles of carbon, sulfur, hydrogen, and nitrogen. Attention is given to the biochemistry of carbon isotope fractionation, carbon isotope fractionation in extant plants and microorganisms, isotope fractionation in the terrestrial carbon cycle, the effects of diagenesis and metamorphism on the isotopic composition of sedimentary carbon, the isotopic composition of sedimentary carbon through time, implications of the sedimentary carbon isotope record, the biochemistry of sulfur isotope fractionation, pathways of the biogeochemical cycle of nitrogen, and the D/H ratio in naturally occurring materials.

An Archaea 5S rRNA analog is stably expressed in Escherichia coli

NASA Technical Reports Server (NTRS)

Yang, Y.; Fox, G. E.

1996-01-01

Mini-genes for 5S-like rRNA were constructed. These genes had a sequence which largely resembles that of the naturally occurring 5S rRNA of a bacterium, Halococcus morrhuae, which phylogenetically belongs to the Archaea. Plasmids carrying the mini-genes were transformed into Escherichia coli (Ec). Ribosomal incorporation was not a prerequisite for stable accumulation of the RNA product. However, only those constructs with a well-base-paired helix I accumulated RNA product. This result strongly implies that this aspect of the structure is likely to be an important condition for stabilizing 5S rRNA-like products. The results are consistent with our current understanding of 5S rRNA processing in Ec. When used in conjunction with rRNA probe technology, the resulting chimeric RNA may be useful as a monitoring tool for genetically engineered microorganisms or naturally occurring organisms that are released into the environment.

Bioorganic Chemistry. A Natural Reunion of the Physical and Life Sciences

PubMed Central

Poulter, C. Dale

2009-01-01

Organic substances were conceived as those found in living organisms. Although the definition was soon broadened to include all carbon-containing compounds, naturally occurring molecules have always held a special fascination for organic chemists. From these beginnings, molecules from nature were indespensible tools as generations of organic chemists developed new techniques for determining structures, analyzed the mechanisms of reactions, explored the effects conformation and stereochemistry on reactions, and found challenging new targets to synthesize. Only recently have organic chemists harnessed the powerful techniques of organic chemistry to study the functions of organic molecules in their biological hosts, the enzymes that synthesize molecules and the complex processes that occur in a cell. In this Perspective, I present a personal account my entrée into bioorganic chemistry as a physical organic chemist and subsequent work to understand the chemical mechanisms of enzyme-catalyzed reactions, to develop techniques to identify and assign hydrogen bonds in tRNAs through NMR studies with isotopically labeled molecules, and to study how structure determines function in biosynthetic enzymes with proteins obtained by genetic engineering. PMID:19323569

Gas hydrate inhibition by perturbation of liquid water structure

NASA Astrophysics Data System (ADS)

Sa, Jeong-Hoon; Kwak, Gye-Hoon; Han, Kunwoo; Ahn, Docheon; Lee, Kun-Hong

2015-06-01

Natural gas hydrates are icy crystalline materials that contain hydrocarbons, which are the primary energy source for this civilization. The abundance of naturally occurring gas hydrates leads to a growing interest in exploitation. Despite their potential as energy resources and in industrial applications, there is insufficient understanding of hydrate kinetics, which hinders the utilization of these invaluable resources. Perturbation of liquid water structure by solutes has been proposed to be a key process in hydrate inhibition, but this hypothesis remains unproven. Here, we report the direct observation of the perturbation of the liquid water structure induced by amino acids using polarized Raman spectroscopy, and its influence on gas hydrate nucleation and growth kinetics. Amino acids with hydrophilic and/or electrically charged side chains disrupted the water structure and thus provided effective hydrate inhibition. The strong correlation between the extent of perturbation by amino acids and their inhibition performance constitutes convincing evidence for the perturbation inhibition mechanism. The present findings bring the practical applications of gas hydrates significantly closer, and provide a new perspective on the freezing and melting phenomena of naturally occurring gas hydrates.

Gas hydrate inhibition by perturbation of liquid water structure.

PubMed

Sa, Jeong-Hoon; Kwak, Gye-Hoon; Han, Kunwoo; Ahn, Docheon; Lee, Kun-Hong

2015-06-17

Natural gas hydrates are icy crystalline materials that contain hydrocarbons, which are the primary energy source for this civilization. The abundance of naturally occurring gas hydrates leads to a growing interest in exploitation. Despite their potential as energy resources and in industrial applications, there is insufficient understanding of hydrate kinetics, which hinders the utilization of these invaluable resources. Perturbation of liquid water structure by solutes has been proposed to be a key process in hydrate inhibition, but this hypothesis remains unproven. Here, we report the direct observation of the perturbation of the liquid water structure induced by amino acids using polarized Raman spectroscopy, and its influence on gas hydrate nucleation and growth kinetics. Amino acids with hydrophilic and/or electrically charged side chains disrupted the water structure and thus provided effective hydrate inhibition. The strong correlation between the extent of perturbation by amino acids and their inhibition performance constitutes convincing evidence for the perturbation inhibition mechanism. The present findings bring the practical applications of gas hydrates significantly closer, and provide a new perspective on the freezing and melting phenomena of naturally occurring gas hydrates.

Discussion on the Development of Green Chemistry and Chemical Engineering

NASA Astrophysics Data System (ADS)

Zhang, Yunshen

2017-11-01

Chemical industry plays a vital role in the development process of national economy. However, in view of the special nature of the chemical industry, a large number of poisonous and harmful substances pose a great threat to the ecological environment and human health in the entire process of raw material acquisition, production, transportation, product manufacturing, and the final practical application. Therefore, it is a general trend to promote the development of chemistry and chemical engineering towards a greener environment. This article will focus on some basic problems occurred in the development process of green chemistry and chemical engineering.

Capillary absorption spectrometer and process for isotopic analysis of small samples

DOE Office of Scientific and Technical Information (OSTI.GOV)

Alexander, M. Lizabeth; Kelly, James F.; Sams, Robert L.

A capillary absorption spectrometer and process are described that provide highly sensitive and accurate stable absorption measurements of analytes in a sample gas that may include isotopologues of carbon and oxygen obtained from gas and biological samples. It further provides isotopic images of microbial communities that allow tracking of nutrients at the single cell level. It further targets naturally occurring variations in carbon and oxygen isotopes that avoids need for expensive isotopically labeled mixtures which allows study of samples taken from the field without modification. The process also permits sampling in vivo permitting real-time ambient studies of microbial communities.

The change of European landscapes: human-nature relationships, public attitudes towards rewilding, and the implications for landscape management in Switzerland.

PubMed

Bauer, Nicole; Wallner, Astrid; Hunziker, Marcel

2009-07-01

The rewilding of landscapes is one of the most important and intensively discussed landscape changes occurring in Switzerland, as the need for agricultural and forest land is decreasing. To ensure that decisions concerning future landscape management will be supported by the public, it is crucial to take public opinion into account. Hence the present study aims to assess the public attitudes towards nature and "rewilding" processes. In order to analyze these attitudes, we sent a standardized questionnaire to 4000 randomly selected households throughout Switzerland. A cluster analysis led to a typology with four different types of human-nature relationship ("nature lovers", "nature sympathizers", "nature-connected users" and "nature controllers") that each characterize a particular attitude towards nature. These human-nature relationship types differ in their attitudes towards rewilding as well, allowing a rough classification of the sample into wilderness opponents (51.1%) and wilderness proponents (49.9%). However both groups agree with regard to their opinion concerning the rules and regulations that should apply in future wilderness areas. The parallels of the human-nature relationship typology of this survey with other typologies, and the implications for further research are discussed. We can conclude that, due to the differences concerning the attitudes towards wilderness between the human-nature relationship types, between the rural and urban dwellers, and between the language regions, a uniform strategy for the designation and management of wilderness areas in Switzerland is not possible. We recommend that, when managing landscape change, all stakeholders are included in a participatory process and we advise a thorough assessment of the attitudes of the involved persons towards nature and rewilding at the start of such processes. Such an assessment would facilitate the identification of well-defined target groups allowing specific interventions and management actions customized to the needs and characteristics of each of these groups. In addition we see the commonalities between wilderness opponents and wilderness proponents concerning the rules in wilderness areas as an ideal starting point for a successful participatory process.

Baseline Geochemistry of Natural Occurring Methane and Saline Groundwater in an Area of Unconventional Shale Gas Development Through Time

NASA Astrophysics Data System (ADS)

Harkness, J.; Darrah, T.; Warner, N. R.; Whyte, C. J.; Moore, M. T.; Millot, R.; Kloppmann, W.; Jackson, R. B.; Vengosh, A.

2017-12-01

Naturally occurring methane is nearly ubiquitous in most sedimentary basins and delineating the effects of anthropogenic contamination sources from geogenic sources is a major challenge for evaluating the impact of unconventional shale gas development on water quality. This study employs a broadly integrated study of various geochemical techniques to investigate the geochemical variations of groundwater and surface water before, during, and after hydraulic fracturing.This approache combines inorganic geochemistry (major cations and anions), stable isotopes of select inorganic constituents including strontium (87Sr/86Sr), boron (δ11B), lithium (δ7Li), and carbon (δ13C-DIC), select hydrocarbon molecular (methane, ethane, propane, butane, and pentane) and isotopic tracers (δ13C-CH4, δ13C-C2H6), tritium (3H), and noble gas elemental and isotopic composition (He, Ne, Ar) to apportion natural and anthropogenic sources of natural gas and salt contaminants both before and after drilling. Methane above 1 ccSTP/L in groundwater samples awas strongly associated with elevated salinity (chloride >50 mg/L).The geochemical and isotopic analysis indicate saline groundwater originated via naturally occurring processes, presumably from the migration of deeper methane-rich brines that have interacted extensively with coal lithologies. The chemistry and gas compostion of both saline and fresh groundwater wells did not change following the installation of nearby shale-gas wells.The results of this study emphasize the value of baseline characterization of water quality in areas of fossil fuel exploration. Overall this study presents a comprehensive geochemical framework that can be used as a template for assessing the sources of elevated hydrocarbons and salts to water resources in areas potentially impacted by oil and gas development.

Comparing natural and artificial carious lesions in human crowns by means of conventional hard x-ray micro-tomography and two-dimensional x-ray scattering with synchrotron radiation

NASA Astrophysics Data System (ADS)

Botta, Lea Maria; White, Shane N.; Deyhle, Hans; Dziadowiec, Iwona; Schulz, Georg; Thalmann, Peter; Müller, Bert

2016-10-01

Dental caries, one of the most prevalent infectious bacterial diseases in the world, is caused by specific types of acid-producing bacteria. Caries is a disease continuum resulting from the earliest loss of ions from apatite crystals through gross cavitation. Enamel dissolution starts when the pH-value drops below 5.5. Neutralizing the pH-value in the oral cavity opposes the process of demineralization, and so caries lesions occur in a dynamic cyclic de-mineralizing/remineralizing environment. Unfortunately, biomimetic regeneration of cavitated enamel is not yet possible, although remineralization of small carious lesions occurs under optimal conditions. Therefore, the development of methods that can regenerate carious lesions, and subsequently recover and retain teeth, is highly desirable. For the present proceedings we analyzed one naturally occurring sub-surface and one artificially produced lesion. For the characterization of artificial and natural lesions micro computed tomography is the method of choice when looking to determine three-dimensional mineral distribution and to quantify the degree of mineralization. In this pilot study we elucidate that the de-mineralized enamel in natural and artificially induced lesions shows comparable X-ray attenuation behavior, thereby implying that the study protocol employed herein seems to be appropriate. Once we know that the lesions are comparable, a series of well-reproducible in vitro experiments on enamel regeneration could be performed. In order to quantify further lesion morphology, the anisotropy of the enamel's nanostructure can be characterized by using spatially resolved, small-angle X-ray scattering. We wanted to demonstrate that the artificially induced defect fittingly resembles the natural carious lesion.

Modeling lung cancer evolution and preclinical response by orthotopic mouse allografts.

PubMed

Ambrogio, Chiara; Carmona, Francisco J; Vidal, August; Falcone, Mattia; Nieto, Patricia; Romero, Octavio A; Puertas, Sara; Vizoso, Miguel; Nadal, Ernest; Poggio, Teresa; Sánchez-Céspedes, Montserrat; Esteller, Manel; Mulero, Francisca; Voena, Claudia; Chiarle, Roberto; Barbacid, Mariano; Santamaría, David; Villanueva, Alberto

2014-11-01

Cancer evolution is a process that is still poorly understood because of the lack of versatile in vivo longitudinal studies. By generating murine non-small cell lung cancer (NSCLC) orthoallobanks and paired primary cell lines, we provide a detailed description of an in vivo, time-dependent cancer malignization process. We identify the acquisition of metastatic dissemination potential, the selection of co-driver mutations, and the appearance of naturally occurring intratumor heterogeneity, thus recapitulating the stochastic nature of human cancer development. This approach combines the robustness of genetically engineered cancer models with the flexibility of allograft methodology. We have applied this tool for the preclinical evaluation of therapeutic approaches. This system can be implemented to improve the design of future treatments for patients with NSCLC. ©2014 American Association for Cancer Research.

Technologically Enhanced Naturally Occurring Radioactive Materials (TENORM) in the Oil and Gas Industry: A Review.

PubMed

Doyi, Israel; Essumang, David Kofi; Dampare, Samuel; Glover, Eric Tetteh

Radiation is part of the natural environment: it is estimated that approximately 80 % of all human exposure comes from naturally occurring or background radiation. Certain extractive industries such as mining and oil logging have the potential to increase the risk of radiation exposure to the environment and humans by concentrating the quantities of naturally occurring radiation beyond normal background levels (Azeri-Chirag-Gunashli 2004).

Advanced oxidation processes for the removal of natural organic matter from drinking water sources: A comprehensive review.

PubMed

Sillanpää, Mika; Ncibi, Mohamed Chaker; Matilainen, Anu

2018-02-15

Natural organic matter (NOM), a key component in aquatic environments, is a complex matrix of organic substances characterized by its fluctuating amounts in water and variable molecular and chemical properties, leading to various interaction schemes with the biogeosphere and hydrologic cycle. These factors, along with the increasing amounts of NOM in surface and ground waters, make the effort of removing naturally-occurring organics from drinking water supplies, and also from municipal wastewater effluents, a challenging task requiring the development of highly efficient and versatile water treatment technologies. Advanced oxidation processes (AOPs) received an increasing amount of attention from researchers around the world, especially during the last decade. The related processes were frequently reported to be among the most suitable water treatment technologies to remove NOM from drinking water supplies and mitigate the formation of disinfection by products (DBPs). Thus, the present work overviews recent research and development studies conducted on the application of AOPs to degrade NOM including UV and/or ozone-based applications, different Fenton processes and various heterogeneous catalytic and photocatalytic oxidative processes. Other non-conventional AOPs such as ultrasonication, ionizing radiation and plasma technologies were also reported. Furthermore, since AOPs are unlikely to achieve complete oxidation of NOM, integration schemes with other water treatment technologies were presented including membrane filtration, adsorption and others processes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Natural transformation occurs independently of the essential actin-like MreB cytoskeleton in Legionella pneumophila

PubMed Central

Juan, Pierre-Alexandre; Attaiech, Laetitia; Charpentier, Xavier

2015-01-01

Natural transformation is the process by which bacteria can actively take up and integrate exogenous DNA thereby providing a source of genetic diversity. Under specific growth conditions the coordinated expression of several genes – a situation referred to as “competence” – allows bacteria to assemble a highly processive and dedicated system that can import high molecular weight DNA. Within the cell these large imported DNA molecules are protected from degradation and brought to the chromosome for recombination. Here, we report elevated expression of mreB during competence in the Gram-negative pathogen Legionella pneumophila. Interestingly a similar observation had previously been reported in the distantly-related Gram-positive organism Bacillus subtilis. MreB is often viewed as the bacterial actin homolog contributing to bacterial morphogenesis by coordinating peptidoglycan-synthesising complexes. In addition MreB is increasingly found to be involved in a growing number of processes including chromosome segregation and motor-driven motility. Using genetic and pharmacological approaches, we examined the possible role of MreB during natural transformation in L. pneumophila. Our data show that natural transformation does not require MreB dynamics and exclude a direct role of MreB filaments in the transport of foreign DNA and its recombination in the chromosome. PMID:26526572

Natural transformation occurs independently of the essential actin-like MreB cytoskeleton in Legionella pneumophila.

PubMed

Juan, Pierre-Alexandre; Attaiech, Laetitia; Charpentier, Xavier

2015-11-03

Natural transformation is the process by which bacteria can actively take up and integrate exogenous DNA thereby providing a source of genetic diversity. Under specific growth conditions the coordinated expression of several genes--a situation referred to as "competence"--allows bacteria to assemble a highly processive and dedicated system that can import high molecular weight DNA. Within the cell these large imported DNA molecules are protected from degradation and brought to the chromosome for recombination. Here, we report elevated expression of mreB during competence in the Gram-negative pathogen Legionella pneumophila. Interestingly a similar observation had previously been reported in the distantly-related Gram-positive organism Bacillus subtilis. MreB is often viewed as the bacterial actin homolog contributing to bacterial morphogenesis by coordinating peptidoglycan-synthesising complexes. In addition MreB is increasingly found to be involved in a growing number of processes including chromosome segregation and motor-driven motility. Using genetic and pharmacological approaches, we examined the possible role of MreB during natural transformation in L. pneumophila. Our data show that natural transformation does not require MreB dynamics and exclude a direct role of MreB filaments in the transport of foreign DNA and its recombination in the chromosome.

Genome-wide Selective Sweeps in Natural Bacterial Populations Revealed by Time-series Metagenomics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chan, Leong-Keat; Bendall, Matthew L.; Malfatti, Stephanie

2014-06-18

Multiple evolutionary models have been proposed to explain the formation of genetically and ecologically distinct bacterial groups. Time-series metagenomics enables direct observation of evolutionary processes in natural populations, and if applied over a sufficiently long time frame, this approach could capture events such as gene-specific or genome-wide selective sweeps. Direct observations of either process could help resolve how distinct groups form in natural microbial assemblages. Here, from a three-year metagenomic study of a freshwater lake, we explore changes in single nucleotide polymorphism (SNP) frequencies and patterns of gene gain and loss in populations of Chlorobiaceae and Methylophilaceae. SNP analyses revealedmore » substantial genetic heterogeneity within these populations, although the degree of heterogeneity varied considerably among closely related, co-occurring Methylophilaceae populations. SNP allele frequencies, as well as the relative abundance of certain genes, changed dramatically over time in each population. Interestingly, SNP diversity was purged at nearly every genome position in one of the Chlorobiaceae populations over the course of three years, while at the same time multiple genes either swept through or were swept from this population. These patterns were consistent with a genome-wide selective sweep, a process predicted by the ‘ecotype model’ of diversification, but not previously observed in natural populations.« less

Genome-wide Selective Sweeps in Natural Bacterial Populations Revealed by Time-series Metagenomics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chan, Leong-Keat; Bendall, Matthew L.; Malfatti, Stephanie

2014-05-12

Multiple evolutionary models have been proposed to explain the formation of genetically and ecologically distinct bacterial groups. Time-series metagenomics enables direct observation of evolutionary processes in natural populations, and if applied over a sufficiently long time frame, this approach could capture events such as gene-specific or genome-wide selective sweeps. Direct observations of either process could help resolve how distinct groups form in natural microbial assemblages. Here, from a three-year metagenomic study of a freshwater lake, we explore changes in single nucleotide polymorphism (SNP) frequencies and patterns of gene gain and loss in populations of Chlorobiaceae and Methylophilaceae. SNP analyses revealedmore » substantial genetic heterogeneity within these populations, although the degree of heterogeneity varied considerably among closely related, co-occurring Methylophilaceae populations. SNP allele frequencies, as well as the relative abundance of certain genes, changed dramatically over time in each population. Interestingly, SNP diversity was purged at nearly every genome position in one of the Chlorobiaceae populations over the course of three years, while at the same time multiple genes either swept through or were swept from this population. These patterns were consistent with a genome-wide selective sweep, a process predicted by the ecotype model? of diversification, but not previously observed in natural populations.« less

In-situ observations of bubble growth in basaltic, andesitic and rhyodacitic melts

NASA Astrophysics Data System (ADS)

Masotta, M.; Ni, H.; Keppler, H.

2013-12-01

Bubble growth strongly affects the physical properties of degassing magmas and their eruption dynamics. Natural samples and products from quench experiments provide only a snapshot of the final state of volatile exsolution, leaving the processes occurring during its early stages unconstrained. In order to fill this gap, we present in-situ high-temperature observations of bubble growth in magmas of different compositions (basalt, andesite and rhyodacite) at 1100 to 1240 °C and 1 bar, obtained using a moissanite cell apparatus. The data show that nucleation occurs at very small degrees of supersaturaturation (<20 MPa in basalt and andesite, ca. 100 MPa in rhyodacite), probably due to heterogeneous nucleation of bubbles occurring simultaneously with the nucleation of crystals. During the early stages of exsolution, melt degassing is the driving mechanism of bubble growth, with coalescence becoming increasingly important as exsolution progresses. Ostwald ripening occurs only at the end of the process and only in basaltic melt. The average bubble growth rate (GR) ranges from 3.4*10-6 to 5.2*10-7 mm/s, with basalt and andesite showing faster growth rates than rhyodacite. The bubble number density (NB) at nucleation ranges from 1.8*108 to 7.9*107 cm-3 and decreases exponentially over time. While the rhyodacite melt maintained a well-sorted bubble-size distribution (BSD) through time, the BSD's of basalt and andesite are much more inhomogeneous. Our experimental observations demonstrate that bubble growth cannot be ascribed to a single mechanism but is rather a combination of many processes, which depend on the physical properties of the melt. Depending on coalescence rate, annealing of bubbles following a single nucleation event can produce complex bubble size distributions. In natural samples, such BSD's may be misinterpreted as resulting from several separate nucleation events. Incipient crystallization upon cooling of a magma may allow bubble nucleation already at very small degrees of supersaturation and could therefore be an important trigger for volatile release and explosive eruptions.

The use of gibberellic acid as a presowing treatment for cherrybark and Nuttall oak acorns

Treesearch

John C. Adams; Joshua P. Adams; R. A. Williams

2010-01-01

The use of gibberellic acid to enhance growth and development in plants has been shown in many species. Gibberellic acid is a naturally occurring hormone that can, in certain concentrations, affect dormancy, flowering, fruit set, growth, frost protection, root formation, and other growth processes. The positive effect on germination by this hormone treatment could help...

Risk-Taking Tendencies and Radon Messages: A Field Experiment Testing an Information Processing Model for Risk Communication.

ERIC Educational Resources Information Center

Ferguson, M. A.; Valenti, JoAnn Myer

Using radon (a naturally-occurring radioactive gas linked to lung cancer) as the health risk factor, a study examined which risk-taking tendencies interact with different health-risk message strategies. A phone survey pretested 837 randomly selected homeowners from three Florida counties with the highest levels of radon in the state (706 agreed to…

Mutagens and carcinogens in foods. Epidemiologic review.

PubMed Central

Hislop, T. G.

1993-01-01

Evidence that diet contributes to the development of cancer is strengthening. This paper examines mutagens and carcinogens, such as naturally occurring substances, products of cooking and food processing, intentional and unintentional additives, and contaminants, found in foods. Such substances are present in minute quantities in the diets of average Canadians. Indication of health risk is largely limited to experimental laboratory evidence. PMID:8499796

Manipulations of Choice Familiarity in Multiple-Choice Testing Support a Retrieval Practice Account of the Testing Effect

ERIC Educational Resources Information Center

Jang, Yoonhee; Pashler, Hal; Huber, David E.

2014-01-01

We performed 4 experiments assessing the learning that occurs when taking a test. Our experiments used multiple-choice tests because the processes deployed during testing can be manipulated by varying the nature of the choice alternatives. Previous research revealed that a multiple-choice test that includes "none of the above" (NOTA)…

Composing Music, Developing Dialogues: An Enactive Perspective on Children's Collaborative Creativity

ERIC Educational Resources Information Center

Veloso, Ana Luisa

2017-01-01

This study aims to provide new insights on the nature of the embodied and collaborative processes related to the emergence of new musical ideas that occur when children are composing in groups. Data was obtained by participant observation of the teacher/researcher and by ten videotaped one-hour musical sessions dedicated to the development of a…

Convergence Properties of a Class of Probabilistic Adaptive Schemes Called Sequential Reproductive Plans. Psychology and Education Series, Technical Report No. 210.

ERIC Educational Resources Information Center

Martin, Nancy

Presented is a technical report concerning the use of a mathematical model describing certain aspects of the duplication and selection processes in natural genetic adaptation. This reproductive plan/model occurs in artificial genetics (the use of ideas from genetics to develop general problem solving techniques for computers). The reproductive…

Method for milling and drilling glass

NASA Technical Reports Server (NTRS)

Rice, S. H. (Inventor)

1980-01-01

A process for machining glass by placing a rotating carbide working surface under minimum pressure against an area of glass to be worked is described. Concurrently the region between the working surface and the area of glass is wet with a lubricant consisting essentially of a petroleum carrier, a complex mixture of esters and a complex mixture of naturally occurring aromatic oils.

Auditory reafferences: the influence of real-time feedback on movement control.

PubMed

Kennel, Christian; Streese, Lukas; Pizzera, Alexandra; Justen, Christoph; Hohmann, Tanja; Raab, Markus

2015-01-01

Auditory reafferences are real-time auditory products created by a person's own movements. Whereas the interdependency of action and perception is generally well studied, the auditory feedback channel and the influence of perceptual processes during movement execution remain largely unconsidered. We argue that movements have a rhythmic character that is closely connected to sound, making it possible to manipulate auditory reafferences online to understand their role in motor control. We examined if step sounds, occurring as a by-product of running, have an influence on the performance of a complex movement task. Twenty participants completed a hurdling task in three auditory feedback conditions: a control condition with normal auditory feedback, a white noise condition in which sound was masked, and a delayed auditory feedback condition. Overall time and kinematic data were collected. Results show that delayed auditory feedback led to a significantly slower overall time and changed kinematic parameters. Our findings complement previous investigations in a natural movement situation with non-artificial auditory cues. Our results support the existing theoretical understanding of action-perception coupling and hold potential for applied work, where naturally occurring movement sounds can be implemented in the motor learning processes.

Nondestructive natural gas hydrate recovery driven by air and carbon dioxide.

PubMed

Kang, Hyery; Koh, Dong-Yeun; Lee, Huen

2014-10-14

Current technologies for production of natural gas hydrates (NGH), which include thermal stimulation, depressurization and inhibitor injection, have raised concerns over unintended consequences. The possibility of catastrophic slope failure and marine ecosystem damage remain serious challenges to safe NGH production. As a potential approach, this paper presents air-driven NGH recovery from permeable marine sediments induced by simultaneous mechanisms for methane liberation (NGH decomposition) and CH₄-air or CH₄-CO₂/air replacement. Air is diffused into and penetrates NGH and, on its surface, forms a boundary between the gas and solid phases. Then spontaneous melting proceeds until the chemical potentials become equal in both phases as NGH depletion continues and self-regulated CH4-air replacement occurs over an arbitrary point. We observed the existence of critical methane concentration forming the boundary between decomposition and replacement mechanisms in the NGH reservoirs. Furthermore, when CO₂ was added, we observed a very strong, stable, self-regulating process of exchange (CH₄ replaced by CO₂/air; hereafter CH₄-CO₂/air) occurring in the NGH. The proposed process will work well for most global gas hydrate reservoirs, regardless of the injection conditions or geothermal gradient.

Nondestructive natural gas hydrate recovery driven by air and carbon dioxide

PubMed Central

Kang, Hyery; Koh, Dong-Yeun; Lee, Huen

2014-01-01

Current technologies for production of natural gas hydrates (NGH), which include thermal stimulation, depressurization and inhibitor injection, have raised concerns over unintended consequences. The possibility of catastrophic slope failure and marine ecosystem damage remain serious challenges to safe NGH production. As a potential approach, this paper presents air-driven NGH recovery from permeable marine sediments induced by simultaneous mechanisms for methane liberation (NGH decomposition) and CH4-air or CH4-CO2/air replacement. Air is diffused into and penetrates NGH and, on its surface, forms a boundary between the gas and solid phases. Then spontaneous melting proceeds until the chemical potentials become equal in both phases as NGH depletion continues and self-regulated CH4-air replacement occurs over an arbitrary point. We observed the existence of critical methane concentration forming the boundary between decomposition and replacement mechanisms in the NGH reservoirs. Furthermore, when CO2 was added, we observed a very strong, stable, self-regulating process of exchange (CH4 replaced by CO2/air; hereafter CH4-CO2/air) occurring in the NGH. The proposed process will work well for most global gas hydrate reservoirs, regardless of the injection conditions or geothermal gradient. PMID:25311102

Mercury in the national parks

USGS Publications Warehouse

Pritz, Colleen Flanagan; Eagles-Smith, Collin A.; Krabbenhoft, David

2014-01-01

One thing is certain: Even for trained researchers, predicting mercury’s behavior in the environment is challenging. Fundamentally it is one of 98 naturally occurring elements, with natural sources, such as volcanoes, and concentrated ore deposits, such as cinnabar. Yet there are also human-caused sources, such as emissions from both coal-burning power plants and mining operations for gold and silver. There are elemental forms, inorganic or organic forms, reactive and unreactive species. Mercury is emitted, then deposited, then re-emitted—thus earning its mercurial reputation. Most importantly, however, it is ultimately transferred into food chains through processes fueled by tiny microscopic creatures: bacteria.

Natural remediation in the Great Lakes

USGS Publications Warehouse

Passino-Reader, Dora R.; Kamrin, Michael A.; Hickey, James P.; Swindoll, C. Michael; Stahl, Ralph G.; Ells, Stephen J.

2000-01-01

Overall, the existence of stricter environmental laws during the last 30 years and a reduction in the manufacturing base in the Great Lakes has resulted in improvement in conditions in harbors, rivers, and nearshore waters. Problems remain, such as the inability to dredge certain harbors and remove sediments because of lack of disposal facilities for contaminated sediments. Because of the wide extent of of contaminated sediments in the Great Lakes, much work remains to be done to document the condition of contaminated areas and the degree to which remediation of these areas is occurring from biotic and abiotic natural processes.

Atomistic Modeling of Corrosion Events at the Interface between a Metal and Its Environment

DOE PAGES

Taylor, Christopher D.

2012-01-01

Atomistic simulation is a powerful tool for probing the structure and properties of materials and the nature of chemical reactions. Corrosion is a complex process that involves chemical reactions occurring at the interface between a material and its environment and is, therefore, highly suited to study by atomistic modeling techniques. In this paper, the complex nature of corrosion processes and mechanisms is briefly reviewed. Various atomistic methods for exploring corrosion mechanisms are then described, and recent applications in the literature surveyed. Several instances of the application of atomistic modeling to corrosion science are then reviewed in detail, including studies ofmore » the metal-water interface, the reaction of water on electrified metallic interfaces, the dissolution of metal atoms from metallic surfaces, and the role of competitive adsorption in controlling the chemical nature and structure of a metallic surface. Some perspectives are then given concerning the future of atomistic modeling in the field of corrosion science.« less

Azaglycomimetics: Natural Occurrence, Biological Activity, and Application

NASA Astrophysics Data System (ADS)

Asano, Naoki

A large number of alkaloids mimicking the structures of monosaccharides or oligosaccharides have been isolated from plants and microorganisms. The sugar mimicking alkaloids with a nitrogen in the ring are called azasugars or iminosugars. Naturally occurring azasugars are classified into five structural classes: polyhydroxylated piperidines, pyrrolidines, indolizidines, pyrrolizidines, and nortropanes. They are easily soluble in water because of their polyhydroxylated structures and inhibit glycosidases because of a structural resemblance to the sugar moiety of the natural substrate. Glycosidases are involved in a wide range of anabolic and catabolic processes, such as digestion, lysosomal catabolism of glycoconjugates, biosynthesis of glycoproteins, and the endoplasmic reticulum (ER) quality control and ER-associated degradation of glycoproteins. Hence, modifying or blocking these processes in vivo by inhibitors is of great interest from a therapeutic point of view. Azasugars are an important class of glycosidase inhibitors and are arousing great interest for instance as antidiabetics, antiobesity drugs, antivirals, and therapeutic agents for some genetic disorders. This review describes the recent studies on isolation, characterization, glycosidase inhibitory activity, and therapeutic application of azaglycomimetics.

Thermochemolysis: A New Sample Preparation Approach for the Detection of Organic Components of Complex Macromolecules in Mars Rocks via Gas Chromatography Mass Spectrometry in SAM on MSL

NASA Technical Reports Server (NTRS)

Eugenbrode, J.; Glavin, D.; Dworkin, J.; Conrad, P.; Mahaffy, P.

2011-01-01

Organic chemicals, when present in extraterrestrial samples, afford precious insight into past and modern conditions elsewhere in the Solar System . No single technology identifies all molecular components because naturally occurring molecules have different chemistries (e.g., polar vs. non-polar, low to high molecular weight) and interface with the ambient sample chemistry in a variety of modes (i.e., organics may be bonded, absorbed or trapped by minerals, liquids, gases, or other organics). More than 90% of organic matter in most natural samples on Earth and in meteorites is composed of complex macromolecules (e.g. biopolymers, complex biomolecules, humic substances, kerogen) because the processes that tend to break down organic molecules also tend towards complexation of the more recalcitrant components. Thus, methodologies that tap the molecular information contained within macromolecules may be critical to detecting extraterrestrial organic matter and assessing the sources and processes influencing its nature.

Characterization and Infrared Emission Spectroscopy of Ball Plasmoid Discharges

NASA Astrophysics Data System (ADS)

Dubowsky, Scott E.; McCall, Benjamin J.

2015-06-01

Plasmas at atmospheric pressure serve many purposes, from ionization sources for ambient mass spectrometry (AMS) to plasma-assisted wound healing. Of the many naturally occurring ambient plasmas, ball lightning is one of the least understood; there is currently no solid explanation in the literature for the formation and lifetime of natural ball lightning. With the first measurements of naturally occurring ball lightning being reported last year, we have worked to replicate the natural phenomenon in order to elucidate the physical and chemical processes by which the plasma is sustained at ambient conditions. We are able to generate ball-shaped plasmoids (self-sustaining plasmas) that are analogous to natural ball lightning using a high-voltage, high-current, pulsed DC system. Improvements to the discharge electronics used in our laboratory and characterization of the plasmoids that are generated from this system will be described. Infrared emission spectroscopy of these plasmoids reveals emission from water and hydroxyl radical -- fitting methods for these molecular species in the complex experimental spectra will be presented. Rotational temperatures for the stretching and bending modes of H2O along with that of OH will be presented, and the non-equilibrium nature of the plasmoid will be discussed in this context. Cen, J.; Yuan, P,; Xue, S. Phys. Rev. Lett. 2014, 112, 035001. Dubowsky, S.E.; Friday, D.M.; Peters, K.C.; Zhao, Z.; Perry, R.H.; McCall, B.J. Int. J. Mass Spectrom. 2015, 376, 39-45.

Venus Flytrap (Dionaea muscipula Solander ex Ellis) Contains Powerful Compounds that Prevent and Cure Cancer

PubMed Central

Gaascht, François; Dicato, Mario; Diederich, Marc

2013-01-01

Chemoprevention uses natural or synthetic molecules without toxic effects to prevent and/or block emergence and development of diseases including cancer. Many of these natural molecules modulate mitogenic signals involved in cell survival, apoptosis, cell cycle regulation, angiogenesis, or on processes involved in the development of metastases occur naturally, especially in fruits and vegetables bur also in non-comestible plants. Carnivorous plants including the Venus flytrap (Dionaea muscipula Solander ex Ellis) are much less investigated, but appear to contain a wealth of potent bioactive secondary metabolites. Aim of this review is to give insight into molecular mechanisms triggered by compounds isolated from these interesting plants with either therapeutic or chemopreventive potential. PMID:23971004

Bioremediation of cyanotoxins.

PubMed

Edwards, Christine; Lawton, Linda A

2009-01-01

Cyanobacteria are a diverse group of mainly aquatic microorganisms which occur globally. Eutrophication (nutrient enrichment) of water bodies, often as a result of human activities, results in prolific grow of cyanobacteria that develop into a thick scum or bloom. Many of these blooms are toxic due to the production of hepatotoxins (microcystins and cylindrospermopsin) and/or neurotoxins (saxitoxins and anatoxins) posing a serious health hazard to humans and animals. The presence of these cyanotoxins is of particular concern in drinking water supplies where conventional water treatment often fails to eliminate them. Hence, there is significant interest in water treatment strategies that ensure the removal of cyanotoxins, with the exploitation of microbes being on such possible approach. As naturally occurring compounds it is assumed that these toxins are readily biodegraded. Furthermore, there is no significant evidence of their accumulation in the environment and their relative stable under a wide range of physico-chemical conditions, suggests biodegradation is the main route for their natural removal from the environment. Microcystins, as the most commonly occurring toxins, have been the most widely studied and hence form the main focus here. The review provides an overview of research into the biodegradation of cyanotoxin, including evidence for natural bioremediation, screening and isolation of toxin biodegrading bacteria, genetic and biochemical elucidation of a degradation pathway along with attempts to harness them for bioremediation through bioactive water treatment processes.

Enantioselective degradation of amphetamine-like environmental micropollutants (amphetamine, methamphetamine, MDMA and MDA) in urban water.

PubMed

Evans, Sian E; Bagnall, John; Kasprzyk-Hordern, Barbara

2016-08-01

This paper aims to understand enantioselective transformation of amphetamine, methamphetamine, MDMA (3,4-methylenedioxy-methamphetamine) and MDA (3,4-methylenedioxyamphetamine) during wastewater treatment and in receiving waters. In order to undertake a comprehensive evaluation of the processes occurring, stereoselective transformation of amphetamine-like compounds was studied, for the first time, in controlled laboratory experiments: receiving water and activated sludge simulating microcosm systems. The results demonstrated that stereoselective degradation, via microbial metabolic processes favouring S-(+)-enantiomer, occurred in all studied amphetamine-based compounds in activated sludge simulating microcosms. R-(-)-enantiomers were not degraded (or their degradation was limited) which proves their more recalcitrant nature. Out of all four amphetamine-like compounds studied, amphetamine was the most susceptible to biodegradation. It was followed by MDMA and methamphetamine. Photochemical processes facilitated degradation of MDMA and methamphetamine but they were not, as expected, stereoselective. Preferential biodegradation of S-(+)-methamphetamine led to the formation of S-(+)-amphetamine. Racemic MDMA was stereoselectively biodegraded by activated sludge which led to its enrichment with R-(-)-enantiomer and formation of S-(+)-MDA. Interestingly, there was only mild stereoselectivity observed during MDMA degradation in rivers. This might be due to different microbial communities utilised during activated sludge treatment and those present in the environment. Kinetic studies confirmed the recalcitrant nature of MDMA. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

The contamination of scientific literature: looking for an antidote

NASA Astrophysics Data System (ADS)

Liotta, Marcello

2017-04-01

Science may have very strong implications for society. The knowledge of the processes occurring around the society represents a good opportunity to take responsible decisions. This is particularly true in the field of geosciences. Earthquakes, volcanic eruptions, landslides, climate changes and many other natural phenomena still need to be further investigated. The role of the scientific community is to increase the knowledge. Each member can share his own ideas and data thus allowing the entire scientific community to receive a precious contribution. The latter one often derives from research activities, which are expensive in terms of consumed time and resources. Nowadays the sharing of scientific results occurs through the publication on scientific journals. The reading of available scientific literature thus represents a unique opportunity to define the state of the art on a specific topic and to address research activities towards something new. When published results are obtained through a rigorous scientific process, they constitute a solid background where each member can add his ideas and evidences. Differently, published results may be affected by scientific misconduct; they constitute a labyrinth where the scientists lose their time in the attempt of truly understanding the natural processes. The normal scientific dialectic should unmask such results, thus avoiding literature contamination and making the scientific framework more stimulating. The scientific community should look for the best practice to reduce the risk of literature contamination.

Degradation of microcystin-RR using boron-doped diamond electrode.

PubMed

Zhang, Chunyong; Fu, Degang; Gu, Zhongze

2009-12-30

Microcystins (MCs), produced by blue-green algae, are one of the most common naturally occurring toxins found in natural environment. The presence of MCs in drinking water sources poses a great threat to people's health. In this study, the degradation behavior of microcystin-RR on boron-doped diamond (BDD) electrode was investigated under galvanostatic conditions. Such parameters as reaction time, supporting electrolyte and applied current density were varied in order to determine their effects on this oxidation process. The experimental results revealed the suitability of electrochemical processes employing BDD electrode for removing MC-RR from the solution. However, the efficient removal of MC-RR only occurred in the presence of sodium chloride that acted as redox mediators and the reaction was mainly affected by the chloride concentration (c(NaCl)) and applied current density (I(appl)). Full and quick removal of 0.50 microg/ml MC-RR in solution was achieved when the operating conditions of c(NaCl) and I(appl) were 20mM and 46.3 mA/cm(2), or 35 mM and 18.2 mA/cm(2) respectively. The kinetics for MC-RR degradation followed a pesudo-first order reaction in most cases, indicating the process was under mass transfer control. As a result of its excellent performance, the BDD technology could be considered as a promising alternative to promote the degradation of MC-RR than chlorination in drinking water supplies.

Benzoic Acid Production with Respect to Starter Culture and Incubation Temperature during Yogurt Fermentation using Response Surface Methodology.

PubMed

Yu, Hyung-Seok; Lee, Na-Kyoung; Jeon, Hye-Lin; Eom, Su Jin; Yoo, Mi-Young; Lim, Sang-Dong; Paik, Hyun-Dong

2016-01-01

Benzoic acid is occasionally used as a raw material supplement in food products and is sometimes generated during the fermentation process. In this study, the production of naturally occurring yogurt preservatives was investigated for various starter cultures and incubation temperatures, and considered food regulations. Streptococcus thermophilus, Lactobacillus acidophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus rhamnosus, Lactobacillus casei, Lactobacillus paracasei, Lactobacillus reuteri, Lactobacillus plantarum, Bifidobacterium longum, Bifidobacterium lactis, Bifidobacterium bifidum, Bifidobacterium infantis, and Bifidobacterium breve were used as yogurt starter cultures in commercial starters. Among these strains, L. rhamnosus and L. paracasei showed the highest production of benzoic acid. Therefore, the use of L. rhamnosus, L. paracasei, S. thermophilus, and different incubation temperatures were examined to optimize benzoic acid production. Response surface methodology (RSM) based on a central composite design was performed for various incubation temperatures (35-44℃) and starter culture inoculum ratios (0-0.04%) in a commercial range of dairy fermentation processes. The optimum conditions were 0.04% L. rhamnosus, 0.01% L. paracasei, 0.02% S. thermophilus, and 38.12℃, and the predicted and estimated concentrations of benzoic acid were 13.31 and 13.94 mg/kg, respectively. These conditions maximized naturally occurring benzoic acid production during the yogurt fermentation process, and the observed production levels satisfied regulatory guidelines for benzoic acid in dairy products.

Benzoic Acid Production with Respect to Starter Culture and Incubation Temperature during Yogurt Fermentation using Response Surface Methodology

PubMed Central

Yoo, Mi-Young; Lim, Sang-Dong

2016-01-01

Benzoic acid is occasionally used as a raw material supplement in food products and is sometimes generated during the fermentation process. In this study, the production of naturally occurring yogurt preservatives was investigated for various starter cultures and incubation temperatures, and considered food regulations. Streptococcus thermophilus, Lactobacillus acidophilus, Lactobacillus delbrueckii subsp. bulgaricus, Lactobacillus rhamnosus, Lactobacillus casei, Lactobacillus paracasei, Lactobacillus reuteri, Lactobacillus plantarum, Bifidobacterium longum, Bifidobacterium lactis, Bifidobacterium bifidum, Bifidobacterium infantis, and Bifidobacterium breve were used as yogurt starter cultures in commercial starters. Among these strains, L. rhamnosus and L. paracasei showed the highest production of benzoic acid. Therefore, the use of L. rhamnosus, L. paracasei, S. thermophilus, and different incubation temperatures were examined to optimize benzoic acid production. Response surface methodology (RSM) based on a central composite design was performed for various incubation temperatures (35-44℃) and starter culture inoculum ratios (0-0.04%) in a commercial range of dairy fermentation processes. The optimum conditions were 0.04% L. rhamnosus, 0.01% L. paracasei, 0.02% S. thermophilus, and 38.12℃, and the predicted and estimated concentrations of benzoic acid were 13.31 and 13.94 mg/kg, respectively. These conditions maximized naturally occurring benzoic acid production during the yogurt fermentation process, and the observed production levels satisfied regulatory guidelines for benzoic acid in dairy products. PMID:27433115

Role of a Streambed's Benthic Biolayer in Enhancing Chemical Reactions in Hyporheic Flow

NASA Astrophysics Data System (ADS)

Harvey, J. W.

2016-12-01

Chemical processing of metals, nutrients, and organic compounds occurs throughout natural waters, however the rate of reactions often is greater at the streambed interface compared with surface water or deeper groundwater. Hydrologic exchange across the sediment interface brings reactive solutes and fine particulate organic matter from surface waters into contact with the streambed biolayer, a zone with algae and other living microflora and fauna, microbial communities, and reactive geochemical coatings on granular sediments. Compared with surface water or deeper hyporheic sediments, the intrinsic rate of reactions may be stimulated in biolayers because of higher rates of metabolic processing and associated redox reactions. Also, hydrologic transport may enhance reaction rates by relieving potential transport limitations through the re-supply of reactive substrates from surface water. As a result the chemical processing that occurs in the biolayer may far exceed processing that occurs in deeper hyporheic flow. Here I highlight new understanding of enhancement of reaction rates and their hydrologic and biogeochemical controls in streambed biolayers compared with hyporheic flow as a whole. The approach distinguishes and quantifies reaction limitation and transport limitation both at the centimeter-scale within the hyporheic zone and at the river network scale where the effect of streambed reactions accumulates and influences downstream water quality.

Biogeochemical gradients above a coal tar DNAPL.

PubMed

Scherr, Kerstin E; Backes, Diana; Scarlett, Alan G; Lantschbauer, Wolfgang; Nahold, Manfred

2016-09-01

Naturally occurring distribution and attenuation processes can keep hydrocarbon emissions from dense non aqueous phase liquids (DNAPL) into the adjacent groundwater at a minimum. In a historically coal tar DNAPL-impacted site, the de facto absence of a plume sparked investigations regarding the character of natural attenuation and DNAPL resolubilization processes at the site. Steep vertical gradients of polycyclic aromatic hydrocarbons, microbial community composition, secondary water quality and redox-parameters were found to occur between the DNAPL-proximal and shallow waters. While methanogenic and mixed-electron acceptor conditions prevailed close to the DNAPL, aerobic conditions and very low dissolved contaminant concentrations were identified in three meters vertical distance from the phase. Comprehensive two-dimensional gas chromatography-mass spectrometry (GC×GC-MS) proved to be an efficient tool to characterize the behavior of the present complex contaminant mixture. Medium to low bioavailability of ferric iron and manganese oxides of aquifer samples was detected via incubation with Shewanella alga and evidence for iron and manganese reduction was collected. In contrast, 16S rDNA phylogenetic analysis revealed the absence of common iron reducing bacteria. Aerobic hydrocarbon degraders were abundant in shallow horizons, while nitrate reducers were dominating in deeper aquifer regions, in addition to a low relative abundance of methanogenic archaea. Partial Least Squares - Canonical Correspondence Analysis (PLS-CCA) suggested that nitrate and oxygen concentrations had the greatest impact on aquifer community structure in on- and offsite wells, which had a similarly high biodiversity (H' and Chao1). Overall, slow hydrocarbon dissolution from the DNAPL appears to dominate natural attenuation processes. This site may serve as a model for developing legal and technical strategies for the treatment of DNAPL-impacted sites where contaminant plumes are absent or shrinking. Copyright © 2015 Elsevier B.V. All rights reserved.

Passive seismic monitoring of natural and induced earthquakes: case studies, future directions and socio-economic relevance

USGS Publications Warehouse

Bohnhoff, Marco; Dresen, Georg; Ellsworth, William L.; Ito, Hisao; Cloetingh, Sierd; Negendank, Jörg

2010-01-01

An important discovery in crustal mechanics has been that the Earth’s crust is commonly stressed close to failure, even in tectonically quiet areas. As a result, small natural or man-made perturbations to the local stress field may trigger earthquakes. To understand these processes, Passive Seismic Monitoring (PSM) with seismometer arrays is a widely used technique that has been successfully applied to study seismicity at different magnitude levels ranging from acoustic emissions generated in the laboratory under controlled conditions, to seismicity induced by hydraulic stimulations in geological reservoirs, and up to great earthquakes occurring along plate boundaries. In all these environments the appropriate deployment of seismic sensors, i.e., directly on the rock sample, at the earth’s surface or in boreholes close to the seismic sources allows for the detection and location of brittle failure processes at sufficiently low magnitude-detection threshold and with adequate spatial resolution for further analysis. One principal aim is to develop an improved understanding of the physical processes occurring at the seismic source and their relationship to the host geologic environment. In this paper we review selected case studies and future directions of PSM efforts across a wide range of scales and environments. These include induced failure within small rock samples, hydrocarbon reservoirs, and natural seismicity at convergent and transform plate boundaries. Each example represents a milestone with regard to bridging the gap between laboratory-scale experiments under controlled boundary conditions and large-scale field studies. The common motivation for all studies is to refine the understanding of how earthquakes nucleate, how they proceed and how they interact in space and time. This is of special relevance at the larger end of the magnitude scale, i.e., for large devastating earthquakes due to their severe socio-economic impact.

Occurrence and overlap of natural disasters, complex emergencies and epidemics during the past decade (1995–2004)

PubMed Central

Spiegel, Paul B; Le, Phuoc; Ververs, Mija-Tesse; Salama, Peter

2007-01-01

Background The fields of expertise of natural disasters and complex emergencies (CEs) are quite distinct, with different tools for mitigation and response as well as different types of competent organizations and qualified professionals who respond. However, natural disasters and CEs can occur concurrently in the same geographic location, and epidemics can occur during or following either event. The occurrence and overlap of these three types of events have not been well studied. Methods All natural disasters, CEs and epidemics occurring within the past decade (1995–2004) that met the inclusion criteria were included. The largest 30 events in each category were based on the total number of deaths recorded. The main databases used were the Emergency Events Database for natural disasters, the Uppsala Conflict Database Program for CEs and the World Health Organization outbreaks archive for epidemics. Analysis During the past decade, 63% of the largest CEs had ≥1 epidemic compared with 23% of the largest natural disasters. Twenty-seven percent of the largest natural disasters occurred in areas with ≥1 ongoing CE while 87% of the largest CEs had ≥1 natural disaster. Conclusion Epidemics commonly occur during CEs. The data presented in this article do not support the often-repeated assertion that epidemics, especially large-scale epidemics, commonly occur following large-scale natural disasters. This observation has important policy and programmatic implications when preparing and responding to epidemics. There is an important and previously unrecognized overlap between natural disasters and CEs. Training and tools are needed to help bridge the gap between the different type of organizations and professionals who respond to natural disasters and CEs to ensure an integrated and coordinated response. PMID:17411460

Geochemical Signature of Natural Water Recharge in the Jungar Basin and Its Response to Climate.

PubMed

Zhu, Bingqi; Yu, Jingjie; Rioual, Patrick

2016-01-01

This paper analyzed the physico-chemical characteristics of natural waters in a drainage system of the Jungar Basin, northwestern China to identify chemical evolution and recharge mechanisms of natural waters in an arid environment. The waters studied are different in mineralization, but are typically carbonate rivers and alkaline in nature. No Cl-dominated water type occurs, indicating an early stage of water evolution. Regolith and geomorphological parameters controlling ground-surface temperature may play a large role in the geological evolution of the water. Three main morphological and hydrological units are reflected in water physico-chemistry. Climate influences the salinization of natural waters substantially. Direct recharge from seasonal snow and ice-melt water and infiltration of rain to the ground are significant recharge processes for natural waters, but recharge from potential deep groundwater may be less important. The enrichment of ions in lakes has been mainly caused by evaporation rather than through the quality change of the recharged water.

Stratigraphic, sedimentologic, and dendrogeomorphic analyses of rapid floodplain formation along the Rio Grande in Big Bend National Park, Texas

USGS Publications Warehouse

Dean, D.J.; Scott, M.L.; Shafroth, P.B.; Schmidt, J.C.

2011-01-01

The channel of the lower Rio Grande in the Big Bend region rapidly narrows during years of low mean and peak flow. We conducted stratigraphic, sedimentologic, and dendrogeomorphic analyses within two long floodplain trenches to precisely reconstruct the timing and processes of recent floodplain formation. We show that the channel of the Rio Grande narrowed through the oblique and vertical accretion of inset floodplains following channel-widening floods in 1978 and 1990-1991. Vertical accretion occurred at high rates, ranging from 16 to 35 cm/yr. Dendrogeomorphic analyses show that the onset of channel narrowing occurred during low-flow years when channel bars obliquely and vertically accreted fine sediment. This initial stage of accretion occurred by both bedload and suspended-load deposition within the active channel. Vegetation became established on top of these fine-grained deposits during years of low peak flow and stabilized these developing surfaces. Subsequent deposition by moderate floods (between 1.5 and 7 yr recurrence intervals) caused additional accretion at rapid rates. Suspended-sediment deposition was dominant in the upper deposits, resulting in the formation of natural levees at the channel margins and the deposition of horizontally bedded, fining-upward deposits in the floodplain trough. Overall, channel narrowing and floodplain formation occurred through an evolution from active-channel to floodplain depositional processes. High-resolution dendrogeomorphic analyses provide the ability to specifically correlate the flow record to the onset of narrowing, the establishment of riparian vegetation, the formation of natural levees, and ultimately, the conversion of portions of the active channel to floodplains. ?? 2011 Geological Society of America.

Natural ageing responses of duplex structured Mg-Li based alloys

PubMed Central

Li, C. Q.; Xu, D. K.; Wang, B. J.; Sheng, L. Y.; Qiao, Y. X.; Han, E. H.

2017-01-01

Natural ageing responses of duplex structured Mg-6%Li and Mg-6%Li-6%Zn-1.2%Y alloys have been investigated. Microstructural analyses revealed that the precipitation and coarsening process of α-Mg particles could occur in β-Li phases of both two alloys during ageing process. Since a certain amount of Mg atoms in β-Li phases were consumed for the precipitation of abundant tiny MgLiZn particles, the size of α-Mg precipitates in Mg-6%Li-6%Zn-1.2%Y alloy was relatively smaller than that in Mg-6%Li alloy. Micro hardness measurements demonstrated that with the ageing time increasing, the α-Mg phases in Mg-6%Li alloy could have a constant hardness value of 41 HV, but the contained β-Li phases exhibited a slight age-softening response. Compared with the Mg-6%Li alloy, the age-softening response of β-Li phases in Mg-6%Li-6%Zn-1.2%Y alloy was much more profound. Meanwhile, a normal age-hardening response of α-Mg phases was maintained. Tensile results indicated that obvious ageing-softening phenomenon in terms of macro tensile strength occurred in both two alloys. Failure analysis demonstrated that for the Mg-6%Li alloy, cracks were preferentially initiated at α-Mg/β-Li interfaces. For the Mg-6%Li-6%Zn-1.2%Y alloy, cracks occurred at both α-Mg/β-Li interfaces and slip bands in α-Mg and β-Li phases. PMID:28053318

Evasion of anti-growth signaling: a key step in tumorigenesis and potential target for treatment and prophylaxis by natural compounds

PubMed Central

Amin, A.R.M. Ruhul; Karpowicz, Phillip A.; Carey, Thomas E.; Arbiser, Jack; Nahta, Rita; Chen, Zhuo G.; Dong, Jin-Tang; Kucuk, Omer; Khan, Gazala N.; Huang, Gloria S.; Mi, Shijun; Lee, Ho-Young; Reichrath, Joerg; Honoki, Kanya; Georgakilas, Alexandros G.; Amedei, Amedeo; Amin, Amr; Helferich, Bill; Boosani, Chandra S.; Ciriolo, Maria Rosa; Chen, Sophie; Mohammed, Sulma I.; Azmi, Asfar S.; Keith, W Nicol; Bhakta, Dipita; Halicka, Dorota; Niccolai, Elena; Fujii, Hiromasa; Aquilano, Katia; Ashraf, S. Salman; Nowsheen, Somaira; Yang, Xujuan; Bilsland, Alan; Shin, Dong M.

2015-01-01

The evasion of anti-growth signaling is an important characteristic of cancer cells. In order to continue to proliferate, cancer cells must somehow uncouple themselves from the many signals that exist to slow down cell growth. Here, we define the anti-growth signaling process, and review several important pathways involved in growth signaling: p53, phosphatase and tensin homolog (PTEN), retinoblastoma protein (Rb), Hippo, growth differentiation factor 15 (GDF15), AT-rich interactive domain 1A (ARID1A), Notch, insulin-like growth factor (IGF), and Krüppel-like factor 5 (KLF5) pathways. Aberrations in these processes in cancer cells involve mutations and thus the suppression of genes that prevent growth, as well as mutation and activation of genes involved in driving cell growth. Using these pathways as examples, we prioritize molecular targets that might be leveraged to promote anti-growth signaling in cancer cells. Interestingly, naturally-occurring phytochemicals found in human diets (either singly or as mixtures) may promote anti-growth signaling, and do so without the potentially adverse effects associated with synthetic chemicals. We review examples of naturally-occurring phytochemicals that may be applied to prevent cancer by antagonizing growth signaling, and propose one phytochemical for each pathway. These are: epigallocatechin-3-gallate (EGCG) for the Rb pathway, luteolin for p53, curcumin for PTEN, porphyrins for Hippo, genistein for GDF15, resveratrol for ARID1A, withaferin A for Notch and diguelin for the IGF1-receptor pathway. The coordination of anti-growth signaling and natural compound studies will provide insight into the future application of these compounds in the clinical setting. PMID:25749195

Solute movement in drained fen peat: a field tracer study in a Somerset (UK) wetland

NASA Astrophysics Data System (ADS)

Baird, Andrew J.; Gaffney, Simon W.

2000-10-01

Little is known about solute transport in peats, despite the obvious importance of solute transport on eco-hydrological processes in both managed and natural peatlands. To address this lack of knowledge, we investigated solute transport processes in an agricultural fen peat using a conservative KBr tracer. The main aim of the study was to elucidate solute transport behaviour in general in this peat, with a more specific aim of investigating whether preferential or bypassing flow occurred. The tracer moved through the peat more rapidly than expected, and the pattern of movement showed clear evidence of plot-scale bypassing flow. The data also provide evidence that bypassing flow occurs in pores at smaller scales. The implications of this study for management of wetland pastures in the Somerset Moors in south-west England are discussed.

Rearrangements of organic peroxides and related processes

PubMed Central

Yaremenko, Ivan A; Vil’, Vera A; Demchuk, Dmitry V

2016-01-01

Summary This review is the first to collate and summarize main data on named and unnamed rearrangement reactions of peroxides. It should be noted, that in the chemistry of peroxides two types of processes are considered under the term rearrangements. These are conventional rearrangements occurring with the retention of the molecular weight and transformations of one of the peroxide moieties after O–O-bond cleavage. Detailed information about the Baeyer−Villiger, Criegee, Hock, Kornblum−DeLaMare, Dakin, Elbs, Schenck, Smith, Wieland, and Story reactions is given. Unnamed rearrangements of organic peroxides and related processes are also analyzed. The rearrangements and related processes of important natural and synthetic peroxides are discussed separately. PMID:27559418

Presence of enteric viruses in freshwater and their removal by the conventional drinking water treatment process.

PubMed Central

Hurst, C. J.

1991-01-01

A review of results published in English or French between 1980 and 1990 was carried out to determine the levels of indigenous human enteric viruses in untreated surface and subsurface freshwaters, as well as in drinking water that had undergone the complete conventional treatment process. For this purpose, the conventional treatment process was defined as an operation that included coagulation followed by sedimentation, filtration, and disinfection. Also assessed was the stepwise efficiency of the conventional treatment process, as practised at full-scale facilities, for removing indigenous viruses from naturally occurring freshwaters. A list was compiled of statistical correlations relating to the occurrence of indigenous viruses in water. PMID:1647273

Proceedings of International Conference on the Role of the Polar Regions in Global Change Held in Fairbanks Alaska on 11-15 June 1990. Volume 1

DTIC Science & Technology

1992-03-01

and occurring at was first noted by Findeisen [1940]. temperatures near -400C were found in the 27 years of data The homogeneous freezing of water at...the likelihood. and distinct pollutant-produced signatire on the nature of the consequences of such processes. REFERENCES Findeisen , W., The formation

Storm hydrograph comparisons of subsurface pipe and stream channel discharge in a small, forested watershed in northern California

Treesearch

Jeffrey S. Albright

1992-01-01

The term piping has been used to describe subsurface erosion processes and concentrated subsurface water discharge. Physical features created by piping have been termed pipes. Piping can occur in natural landscapes due to individual or combined effects of mechanical (e.g., corrasion), chemical (e.g., soil dispersion), or biotic (e.g., animal burrowing) forces...

An Objective Method of Measuring Psychological States Associated With Changes in Neural Function: Content Analysis of Verbal Behavior.

ERIC Educational Resources Information Center

Gottschalk, Louis A.

This paper examines the use of content analysis of speech in the objective recording and measurement of changes in emotional and cognitive function of humans in whom natural or experimental changes in neural status have occurred. A brief description of the data gathering process, details of numerous physiological effects, an anxiety scale, and a…

Response of deep groundwater to land use change in desert basins of the Trans-Pecos region, Texas, USA: Effects on infiltration, recharge, and nitrogen fluxes

USGS Publications Warehouse

Robertson, Wendy Marie; Böhlke, John Karl; Sharp, John M.

2017-01-01

Quantifying the effects of anthropogenic processes on groundwater in arid regions can be complicated by thick unsaturated zones with long transit times. Human activities can alter water and nutrient fluxes, but their impact on groundwater is not always clear. This study of basins in the Trans-Pecos region of Texas links anthropogenic land use and vegetation change with alterations to unsaturated zone fluxes and regional increases in basin groundwater NO3−concentrations. Median increases in groundwater NO3− (by 0.7–0.9 mg-N/l over periods ranging from 10 to 50+ years) occurred despite low precipitation (220–360 mm/year), high potential evapotranspiration (~1570 mm/year), and thick unsaturated zones (10–150+ m). Recent model simulations indicate net infiltration and groundwater recharge can occur beneath Trans-Pecos basin floors, and may have increased due to irrigation and vegetation change. These processes were investigated further with chemical and isotopic data from groundwater and unsaturated zone cores. Some unsaturated zone solute profiles indicate flushing of natural salt accumulations has occurred. Results are consistent with human-influenced flushing of naturally accumulated unsaturated zone nitrogen as an important source of NO3− to the groundwater. Regional mass balance calculations indicate the mass of natural unsaturated zone NO3− (122–910 kg-N/ha) was sufficient to cause the observed groundwater NO3− increases, especially if augmented locally with the addition of fertilizer N. Groundwater NO3− trends can be explained by small volumes of high NO3− modern recharge mixed with larger volumes of older groundwater in wells. This study illustrates the importance of combining long-term monitoring and targeted process studies to improve understanding of human impacts on recharge and nutrient cycling in arid regions, which are vulnerable to the effects of climate change and increasing human reliance on dryland ecosystems.

Salvage logging, ecosystem processes, and biodiversity conservation.

PubMed

Lindenmayer, D B; Noss, R F

2006-08-01

We summarize the documented and potential impacts of salvage logging--a form of logging that removes trees and other biological material from sites after natural disturbance. Such operations may reduce or eliminate biological legacies, modify rare postdisturbance habitats, influence populations, alter community composition, impair natural vegetation recovery, facilitate the colonization of invasive species, alter soil properties and nutrient levels, increase erosion, modify hydrological regimes and aquatic ecosystems, and alter patterns of landscape heterogeneity These impacts can be assigned to three broad and interrelated effects: (1) altered stand structural complexity; (2) altered ecosystem processes and functions; and (3) altered populations of species and community composition. Some impacts may be different from or additional to the effects of traditional logging that is not preceded by a large natural disturbance because the conditions before, during, and after salvage logging may differ from those that characterize traditional timber harvesting. The potential impacts of salvage logging often have been overlooked, partly because the processes of ecosystem recovery after natural disturbance are still poorly understood and partly because potential cumulative effects of natural and human disturbance have not been well documented. Ecologically informed policies regarding salvage logging are needed prior to major natural disturbances so that when they occur ad hoc and crisis-mode decision making can be avoided. These policies should lead to salvage-exemption zones and limits on the amounts of disturbance-derived biological legacies (e.g., burned trees, logs) that are removed where salvage logging takes place. Finally, we believe new terminology is needed. The word salvage implies that something is being saved or recovered, whereas from an ecological perspective this is rarely the case.

Processing structure in language and music: a case for shared reliance on cognitive control.

PubMed

Slevc, L Robert; Okada, Brooke M

2015-06-01

The relationship between structural processing in music and language has received increasing interest in the past several years, spurred by the influential Shared Syntactic Integration Resource Hypothesis (SSIRH; Patel, Nature Neuroscience, 6, 674-681, 2003). According to this resource-sharing framework, music and language rely on separable syntactic representations but recruit shared cognitive resources to integrate these representations into evolving structures. The SSIRH is supported by findings of interactions between structural manipulations in music and language. However, other recent evidence suggests that such interactions also can arise with nonstructural manipulations, and some recent neuroimaging studies report largely nonoverlapping neural regions involved in processing musical and linguistic structure. These conflicting results raise the question of exactly what shared (and distinct) resources underlie musical and linguistic structural processing. This paper suggests that one shared resource is prefrontal cortical mechanisms of cognitive control, which are recruited to detect and resolve conflict that occurs when expectations are violated and interpretations must be revised. By this account, musical processing involves not just the incremental processing and integration of musical elements as they occur, but also the incremental generation of musical predictions and expectations, which must sometimes be overridden and revised in light of evolving musical input.

Laboratory simulations of lunar darkening processes

NASA Technical Reports Server (NTRS)

Hapke, B.

1993-01-01

It was clear long before the Apollo missions that a darkening process occurs on the moon. However, its nature remains controversial and elusive. Current evidence implies that the darkening is associated with, and is probably caused by, submicroscopic metallic iron in the regolith. Questions discussed at the workshop include: (1) under what conditions will impact vitrification produce a dark glass; (2) what is the role of the submicroscopic metallic Fe (SMFe) in the lunar darkening process; (3) how is the SMFe produced; (4) is there a significant component of the regolith that has been deposited from a vapor, if so, what form is it in, and how can it be recognized, what are its effects on the chemistry of the regolith; (5) how do the processes of impact vitrification, vaporization, sputtering, and SMFe production vary as a function of distance from the sun and location in planetary magnetospheres; and (6) what other processes might affect optical properties. Ices have lower melting and boiling temperatures and sputtering yields several orders of magnitude larger than silicates. Hence, analogous processes will occur to an even greater extent on satellites of the outer planets, and these questions are relevant to those bodies as well.

Filtered molasses concentrate from sugar cane: natural functional ingredient effective in lowering the glycaemic index and insulin response of high carbohydrate foods.

PubMed

Wright, Alison G; Ellis, Timothy P; Ilag, Leodevico L

2014-12-01

An aqueous filtered molasses concentrate (FMC) sourced from sugar cane was used as a functional ingredient in a range of carbohydrate-containing foods to reduce glycaemic response. When compared to untreated controls, postprandial glucose responses in the test products were reduced 5-20%, assessed by accredited glycaemic index (GI) testing. The reduction in glucose response in the test foods was dose-dependent and directly proportional to the ratio of FMC added to the amount of available carbohydrate in the test products. The insulin response to the foods was also reduced with FMC addition as compared to untreated controls. Inclusion of FMC in test foods did not replace any formulation ingredients; it was incorporated as an additional ingredient to existing formulations. Filtered molasses concentrate, made by a proprietary and patented process, contains many naturally occurring compounds. Some of the identified compounds are known to influence carbohydrate metabolism, and include phenolic compounds, minerals and organic acids. FMC, sourced from a by-product of sugar cane processing, shows potential as a natural functional ingredient capable of modifying carbohydrate metabolism and contributing to GI reduction of processed foods and beverages.

Bacterial communities associated with hydraulic fracturing fluids in thermogenic natural gas wells in North Central Texas, USA.

PubMed

Struchtemeyer, Christopher G; Elshahed, Mostafa S

2012-07-01

Hydraulic fracturing is used to increase the permeability of shale gas formations and involves pumping large volumes of fluids into these formations. A portion of the frac fluid remains in the formation after the fracturing process is complete, which could potentially contribute to deleterious microbially induced processes in natural gas wells. Here, we report on the geochemical and microbiological properties of frac and flowback waters from two newly drilled natural gas wells in the Barnett Shale in North Central Texas. Most probable number studies showed that biocide treatments did not kill all the bacteria in the fracturing fluids. Pyrosequencing-based 16S rRNA diversity analyses indicated that the microbial communities in the flowback waters were less diverse and completely distinct from the communities in frac waters. These differences in frac and flowback water communities appeared to reflect changes in the geochemistry of fracturing fluids that occurred during the frac process. The flowback communities also appeared well adapted to survive biocide treatments and the anoxic conditions and high temperatures encountered in the Barnett Shale. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

The handicap process favors exaggerated, rather than reduced, sexual ornaments.

PubMed

Tazzyman, Samuel J; Iwasa, Yoh; Pomiankowski, Andrew

2014-09-01

Why are traits that function as secondary sexual ornaments generally exaggerated in size compared to the naturally selected optimum, and not reduced? Because they deviate from the naturally selected optimum, traits that are reduced in size will handicap their bearer, and could thus provide an honest signal of quality to a potential mate. Thus if secondary sexual ornaments evolve via the handicap process, current theory suggests that reduced ornamentation should be as frequent as exaggerated ornamentation, but this is not the case. To try to explain this discrepancy, we analyze a simple model of the handicap process. Our analysis shows that asymmetries in costs of preference or ornament with regard to exaggeration and reduction cannot fully explain the imbalance. Rather, the bias toward exaggeration can be best explained if either the signaling efficacy or the condition dependence of a trait increases with size. Under these circumstances, evolution always leads to more extreme exaggeration than reduction: although the two should occur just as frequently, exaggerated secondary sexual ornaments are likely to be further removed from the naturally selected optimum than reduced ornaments. © 2014 The Authors. Evolution published by Wiley Periodicals, Inc. on behalf of The Society for the Study of Evolution.

Spatio-Temporal Detection of the Thiomonas Population and the Thiomonas Arsenite Oxidase Involved in Natural Arsenite Attenuation Processes in the Carnoulès Acid Mine Drainage

PubMed Central

Hovasse, Agnès; Bruneel, Odile; Casiot, Corinne; Desoeuvre, Angélique; Farasin, Julien; Hery, Marina; Van Dorsselaer, Alain; Carapito, Christine; Arsène-Ploetze, Florence

2016-01-01

The acid mine drainage (AMD) impacted creek of the Carnoulès mine (Southern France) is characterized by acid waters with a high heavy metal content. The microbial community inhabiting this AMD was extensively studied using isolation, metagenomic and metaproteomic methods, and the results showed that a natural arsenic (and iron) attenuation process involving the arsenite oxidase activity of several Thiomonas strains occurs at this site. A sensitive quantitative Selected Reaction Monitoring (SRM)-based proteomic approach was developed for detecting and quantifying the two subunits of the arsenite oxidase and RpoA of two different Thiomonas groups. Using this approach combined with FISH and pyrosequencing-based 16S rRNA gene sequence analysis, it was established here for the first time that these Thiomonas strains are ubiquitously present in minor proportions in this AMD and that they express the key enzymes involved in natural remediation processes at various locations and time points. In addition to these findings, this study also confirms that targeted proteomics applied at the community level can be used to detect weakly abundant proteins in situ. PMID:26870729

Industrial applications of new sulphur biotechnology.

PubMed

Janssen, A J; Ruitenberg, R; Buisman, C J

2001-01-01

The emission of sulphur compounds into the environment is undesirable because of their acidifying characteristics. The processing of sulphidic ores, oil refining and sulphuric acid production are major sources of SO2 emissions. Hydrogen sulphide is emitted into the environment as dissolved sulphide in wastewater or as H2S in natural gas, biogas, syngas or refinery gases. Waste streams containing sulphate are generated by many industries, including mining, metallurgical, pulp and paper and petrochemical industries. Applying process technologies that rely on the biological sulphur cycle can prevent environmental pollution. In nature sulphur compounds may cycle through a series of oxidation states (-2, 0, +2, +4, +6). Bacteria of a wide range of genera gain metabolic energy from either oxidising or reducing sulphur compounds. Paques B.V. develops and constructs reactor systems to remove sulphur compounds from aqueous and gaseous streams by utilising naturally occurring bacteria from the sulphur cycle. Due to the presence of sulphide, heavy metal removal is also achieved with very high removal efficiencies. Ten years of extensive laboratory and pilot plant research has, to date, resulted in the construction of over 30 full-scale installations. This paper presents key processes from the sulphur cycle and discusses recent developments about their application in industry.

Actin retrograde flow controls natural killer cell response by regulating the conformation state of SHP-1.

PubMed

Matalon, Omri; Ben-Shmuel, Aviad; Kivelevitz, Jessica; Sabag, Batel; Fried, Sophia; Joseph, Noah; Noy, Elad; Biber, Guy; Barda-Saad, Mira

2018-03-01

Natural killer (NK) cells are a powerful weapon against viral infections and tumor growth. Although the actin-myosin (actomyosin) cytoskeleton is crucial for a variety of cellular processes, the role of mechanotransduction, the conversion of actomyosin mechanical forces into signaling cascades, was never explored in NK cells. Here, we demonstrate that actomyosin retrograde flow (ARF) controls the immune response of primary human NK cells through a novel interaction between β-actin and the SH2-domain-containing protein tyrosine phosphatase-1 (SHP-1), converting its conformation state, and thereby regulating NK cell cytotoxicity. Our results identify ARF as a master regulator of the NK cell immune response. Since actin dynamics occur in multiple cellular processes, this mechanism might also regulate the activity of SHP-1 in additional cellular systems. © 2018 The Authors.

US Army Medical Research and Development Technical Report

DTIC Science & Technology

1975-07-01

very similar in extent and appearance to naturally occurring human infections and the armadillo appears to be the best experimental model for...guinea pig skin produced by intradermal injection of toxin fractions resemble the early changes in naturally occurring human infections. In both there... naturally occurring human infections. In both there is extensive necrosis, undermining of the margins of the lesions and a spreading contiguous necrosis

Immunochemical Studies on Selected Marine Toxins

DTIC Science & Technology

1993-05-31

6) Critical evaluation of established immunoassays was made through analysis of various naturally -occurring MCYST containing samples. We found that...hepatopancreas of toxic clams rather than the soft tissues. Microcystin could also be detected by ELISA in naturally -occurring algae bloom samples that...antibody against MCYST 13 7. Other immunochemical studies on MCYST 13 a. Analysis of MCYST in algae and various samples collected from naturally -occurring

Distinguishing solid bitumens formed by thermochemical sulfate reduction and thermal chemical alteration

USGS Publications Warehouse

Kelemen, S.R.; Walters, C.C.; Kwiatek, P.J.; Afeworki, M.; Sansone, M.; Freund, H.; Pottorf, R.J.; Machel, H.G.; Zhang, T.; Ellis, G.S.; Tang, Y.; Peters, K.E.

2008-01-01

Insoluble solid bitumens are organic residues that can form by the thermal chemical alteration (TCA) or thermochemical sulfate reduction (TSR) of migrated petroleum. TCA may actually encompass several low temperature processes, such as biodegradation and asphaltene precipitation, followed by thermal alteration. TSR is an abiotic redox reaction where petroleum is oxidized by sulfate. It is difficult to distinguish solid bitumens associated with TCA of petroleum from those associated with TSR when both processes occur at relatively high temperature. The focus of the present work was to characterize solid bitumen samples associated with TCA or TSR using X-ray photoelectron spectroscopy (XPS). XPS is a surface analysis conducted on either isolated or in situ (>25 ??m diameter) solid bitumen that can provide the relative abundance and chemical speciation of carbon, organic and inorganic heteroatoms (NSO). In this study, naturally occurring solid bitumens from three locations, Nisku Fm. Brazeau River area (TSR-related), LaBarge Field Madison Fm. (TSR-related), and the Alaskan Brooks range (TCA-related), are compared to organic solids generated during laboratory simulation of the TSR and TCA processes. The abundance and chemical nature of organic nitrogen and sulfur in solid bitumens can be understood in terms of the nature of (1) petroleum precursor molecules, (2) the concentration of nitrogen by way of thermal stress and (3) the mode of sulfur incorporation. TCA solid bitumens originate from polar materials that are initially rich in sulfur and nitrogen. Aromaticity and nitrogen increase as thermal stress cleaves aliphatic moieties and condensation reactions take place. Organic sulfur in TCA organic solids remains fairly constant with increasing maturation (3.5 to ???17 sulfur per 100 carbons) into aromatic structures and to the low levels of nitrogen in their hydrocarbon precursors. Hence, XPS results provide organic chemical composition information that helps to distinguish whether solid bitumen, either in situ or removed and concentrated from the rock matrix, was formed via the TCA or TRS process. ?? 2008 Elsevier Ltd.

Geosocial process and its regularities

NASA Astrophysics Data System (ADS)

Vikulina, Marina; Vikulin, Alexander; Dolgaya, Anna

2015-04-01

Natural disasters and social events (wars, revolutions, genocides, epidemics, fires, etc.) accompany each other throughout human civilization, thus reflecting the close relationship of these phenomena that are seemingly of different nature. In order to study this relationship authors compiled and analyzed the list of the 2,400 natural disasters and social phenomena weighted by their magnitude that occurred during the last XXXVI centuries of our history. Statistical analysis was performed separately for each aggregate (natural disasters and social phenomena), and for particular statistically representative types of events. There was 5 + 5 = 10 types. It is shown that the numbers of events in the list are distributed by logarithmic law: the bigger the event, the less likely it happens. For each type of events and each aggregate the existence of periodicities with periods of 280 ± 60 years was established. Statistical analysis of the time intervals between adjacent events for both aggregates showed good agreement with Weibull-Gnedenko distribution with shape parameter less than 1, which is equivalent to the conclusion about the grouping of events at small time intervals. Modeling of statistics of time intervals with Pareto distribution allowed to identify the emergent property for all events in the aggregate. This result allowed the authors to make conclusion about interaction between natural disasters and social phenomena. The list of events compiled by authors and first identified properties of cyclicity, grouping and interaction process reflected by this list is the basis of modeling essentially unified geosocial process at high enough statistical level. Proof of interaction between "lifeless" Nature and Society is fundamental and provided a new approach to forecasting demographic crises with taking into account both natural disasters and social phenomena.

Eco-friendly microwave-assisted protocol to prepare hyaluronan-fatty acid conjugates and to induce their self-assembly process.

PubMed

Calce, Enrica; Mercurio, Flavia Anna; Leone, Marilisa; Saviano, Michele; De Luca, Stefania

2016-06-05

An environmentally sustainable and energy-efficient synthetic process has been developed to prepare hyaluronan-based nano-sized material. It consists in a microwave-promoted acylation of the hydroxyl function of the polysaccharide with natural fatty acids, performed under solvent-free conditions. The efficient interaction of the solid reagents with the MW radiation accounts for the obtained high yielded products. The self-assembly process of the obtained compounds very fast occurred in an aqueous medium under MW-radiation, thus allowing the development of a green protocol for the nano-particles preparation. Copyright © 2016 Elsevier Ltd. All rights reserved.

A review of assertions about the processes and outcomes of social learning in natural resource management.

PubMed

Cundill, G; Rodela, R

2012-12-30

Social learning has become a central theme in natural resource management. This growing interest is underpinned by a number of assertions about the outcomes of social learning, and about the processes that support these outcomes. Yet researchers and practitioners who seek to engage with social learning through the natural resource management literature often become disorientated by the myriad processes and outcomes that are identified. We trace the roots of current assertions about the processes and outcomes of social learning in natural resource management, and assess the extent to which there is an emerging consensus on these assertions. Results suggest that, on the one hand, social learning is described as taking place through deliberative interactions amongst multiple stakeholders. During these interactions, it is argued that participants learn to work together and build relationships that allow for collective action. On the other hand, social learning is described as occurring through deliberate experimentation and reflective practice. During these iterative cycles of action, monitoring and reflection, participants learn how to cope with uncertainty when managing complex systems. Both of these processes, and their associated outcomes, are referred to as social learning. Where, therefore, should researchers and practitioners focus their attention? Results suggest that there is an emerging consensus that processes that support social learning involve sustained interaction between stakeholders, on-going deliberation and the sharing of knowledge in a trusting environment. There is also an emerging consensus that the key outcome of such learning is improved decision making underpinned by a growing awareness of human-environment interactions, better relationships and improved problem-solving capacities for participants. Copyright © 2012 Elsevier Ltd. All rights reserved.

Modeling Child-Nature Interaction in a Nature Preschool: A Proof of Concept.

PubMed

Kahn, Peter H; Weiss, Thea; Harrington, Kit

2018-01-01

This article provides a proof of concept for an approach to modeling child-nature interaction based on the idea of interaction patterns : characterizations of essential features of interaction between humans and nature, specified abstractly enough such that countless different instantiations of each one can occur - in more domestic or wild forms - given different types of nature, people, and purposes. The model draws from constructivist psychology, ecological psychology, and evolutionary psychology, and is grounded in observational data collected through a time-sampling methodology at a nature preschool. Through using a nature language that emphasizes ontogenetic and phylogenetic significance, seven keystone interaction patterns are described for this nature preschool: using one's body vigorously in nature, striking wood on wood, constructing shelter, being in solitude in nature, lying on earth, cohabiting with a wild animal , and being outside in weather . These 7 interactions patterns are then brought together with 13 other patterns published elsewhere to provide a total of 20 keystone interaction patterns that begin to fill out the model, and to show its promise. Discussion focuses on what the model aims to be in terms of both product and process, on what work the model can currently do, and how to further develop the model.

The Role of Reticulate Evolution in Creating Innovation and Complexity

PubMed Central

Swithers, Kristen S.; Soucy, Shannon M.; Gogarten, J. Peter

2012-01-01

Reticulate evolution encompasses processes that conflict with traditional Tree of Life efforts. These processes, horizontal gene transfer (HGT), gene and whole-genome duplications through allopolyploidization, are some of the main driving forces for generating innovation and complexity. HGT has a profound impact on prokaryotic and eukaryotic evolution. HGTs can lead to the invention of new metabolic pathways and the expansion and enhancement of previously existing pathways. It allows for organismal adaptation into new ecological niches and new host ranges. Although many HGTs appear to be selected for because they provide some benefit to their recipient lineage, other HGTs may be maintained by chance through random genetic drift. Moreover, some HGTs that may initially seem parasitic in nature can cause complexity to arise through pathways of neutral evolution. Another mechanism for generating innovation and complexity, occurring more frequently in eukaryotes than in prokaryotes, is gene and genome duplications, which often occur through allopolyploidizations. We discuss how these different evolutionary processes contribute to generating innovation and complexity. PMID:22844638

Slowly switching between environments facilitates reverse evolution in small populations

NASA Astrophysics Data System (ADS)

Tan, Longzhi; Gore, Jeff

2011-03-01

The rate at which a physical process occurs usually changes the behavior of a system. In thermodynamics, the reversibility of a process generally increases when it occurs at an infinitely slow rate. In biological evolution, adaptations to a new environment may be reversed by evolution in the ancestral environment. Such fluctuating environments are ubiquitous in nature, although how the rate of switching affects reverse evolution is unknown. Here we use a computational approach to quantify evolutionary reversibility as a function of the rate of switching between two environments. For small population sizes, which travel on landscapes as random walkers, we find that both genotypic and phenotypic reverse evolution increase at slow switching rates. However, slow switching of environments decreases evolutionary reversibility for a greedy walker, corresponding to large populations (extensive clonal interference). We conclude that the impact of the switching rate for biological evolution is more complicated than other common physical processes, and that a quantitative approach may yield significant insight into reverse evolution.

The biology of deception: emotion and morphine.

PubMed

Stefano, G B; Fricchione, G L

1995-01-01

The biology of deception suggests that denial-like processes are at the core of the cognitive coping. In this regard, with cognitive ability, one associates or assumes that this process occurs by way of a 'rational' mind. Such a detailed cognitive process as being rational would also lead, counter intuitively, to inactivity and or major delays in conclusion reaching. Thus, our perceived rationality may also be a deceptive behavioral response. Of equal noteworthyness, man is also 'emotional'. We surmise that emotion represents the pre-cognitive short-cut to overcome this potential for excessive rationality. In this light, we may explain certain psychiatric disorders such as obsessive-compulsive behavior as emotional extremes dealing with cognitive habits used to bind anxiety operating most probably at the pre-cognitive level. Given recent discoveries in neuroimmunology and an understanding of naturally occurring morphine as both an immune and neurological down-regulatory substance we hypothesize that abnormalities associated with emotional extremes may be due, in part, to morphinergic imbalances.

Compositions and methods for making selenocysteine containing polypeptides

DOEpatents

Soll, Dieter; Aldag, Caroline; Hohn, Michael

2016-10-11

Non-naturally occurring tRNA.sup.Sec and methods of using them for recombinant expression of proteins engineered to include one or more selenocysteine residues are disclosed. The non-naturally occurring tRNA.sup.Sec can be used for recombinant manufacture of selenocysteine containing polypeptides encoded by mRNA without the requirement of an SECIS element. In some embodiments, selenocysteine containing polypeptides are manufactured by co-expressing a non-naturally occurring tRNA.sup.Sec a recombinant expression system, such as E. coli, with SerRS, EF-Tu, SelA, or PSTK and SepSecS, and an mRNA with at least one codon that recognizes the anticodon of the non-naturally occurring tRNA.sup.Sec.

Natural selection in chemical evolution.

PubMed

Fernando, Chrisantha; Rowe, Jonathan

2007-07-07

We propose that chemical evolution can take place by natural selection if a geophysical process is capable of heterotrophic formation of liposomes that grow at some base rate, divide by external agitation, and are subject to stochastic chemical avalanches, in the absence of nucleotides or any monomers capable of modular heredity. We model this process using a simple hill-climbing algorithm, and an artificial chemistry that is unique in exhibiting conservation of mass and energy in an open thermodynamic system. Selection at the liposome level results in the stabilization of rarely occurring molecular autocatalysts that either catalyse or are consumed in reactions that confer liposome level fitness; typically they contribute in parallel to an increasingly conserved intermediary metabolism. Loss of competing autocatalysts can sometimes be adaptive. Steady-state energy flux by the individual increases due to the energetic demands of growth, but also of memory, i.e. maintaining variations in the chemical network. Self-organizing principles such as those proposed by Kauffman, Fontana, and Morowitz have been hypothesized as an ordering principle in chemical evolution, rather than chemical evolution by natural selection. We reject those notions as either logically flawed or at best insufficient in the absence of natural selection. Finally, a finite population model without elitism shows the practical evolutionary constraints for achieving chemical evolution by natural selection in the lab.

Central tarsal bone fracture in the border collie.

PubMed

Guilliard, M

2007-07-01

Fracture of the plantar process of the central tarsal bone together with a dorsomedial displacement of the body of the bone was seen in six border collies. All injuries occurred during free exercise, with no extrinsic trauma. Three dogs had concomitant tarsal fractures. Primary treatment was by lag screwing the central tarsal bone to the fourth tarsal bone. All cases eventually made an excellent recovery. The superficial radiographic appearance was of a luxation of the bone as reported in a previous series, but appraisal of the radiographs showed evidence of fracture in all cases. A cadaver study to assess the mechanism of luxation showed that it is unlikely to occur naturally.

Modelling seasonal variations of natural radioactivity in soils: A case study in southern Italy

NASA Astrophysics Data System (ADS)

Guagliardi, Ilaria; Rovella, Natalia; Apollaro, Carmine; Bloise, Andrea; Rosa, Rosanna De; Scarciglia, Fabio; Buttafuoco, Gabriele

2016-12-01

The activity of natural radionuclides in soil has become an environmental concern for local public and national authorities because of the harmful effects of radiation exposure on human health. In this context, modelling and mapping the activity of natural radionuclides in soil is an important research topic. The study was aimed to model, in a spatial sense, the soil radioactivity in an urban and peri-urban soils area in southern Italy to analyse the seasonal influence on soil radioactivity. Measures of gamma radiation naturally emitted through the decay of radioactive isotopes (potassium, uranium and thorium) were analysed using a geostatistical approach to map the spatial distribution of soil radioactivity. The activity of three radionuclides was measured at 181 locations using a high-resolution ?-ray spectrometry. To take into account the influence of season, the measurements were carried out in summer and in winter. Activity data were analysed by using a geostatistical approach and zones of relatively high or low radioactivity were delineated. Among the main processes which influence natural radioactivity such as geology, geochemical, pedological, and ecological processes, results of this study showed a prominent control of radio-emission measurements by seasonal changes. Low natural radioactivity levels were measured in December associated with winter weather and moist soil conditions (due to high rainfall and low temperature), and higher activity values in July, when the soil was dry and no precipitations occurred.

Comparison of Overall Resource Consumption of Biosolids Management System Processes Using Exergetic Life Cycle Assessment.

PubMed

Alanya, Sevda; Dewulf, Jo; Duran, Metin

2015-08-18

This study focused on the evaluation of biosolids management systems (BMS) from a natural resource consumption point of view. Additionally, the environmental impact of the facilities was benchmarked using Life Cycle Assessment (LCA) to provide a comprehensive assessment. This is the first study to apply a Cumulative Exergy Extraction from the Natural Environment (CEENE) method for an in-depth resource use assessment of BMS where two full-scale BMS and seven system variations were analyzed. CEENE allows better system evaluation and understanding of how much benefit is achievable from the products generated by BMS, which have valorization potential. LCA results showed that environmental burden is mostly from the intense electricity consumption. The CEENE analysis further revealed that the environmental burden is due to the high consumption of fossil and nuclear-based natural resources. Using Cumulative Degree of Perfection, higher resource-use efficiency, 53%, was observed in the PTA-2 where alkaline stabilization rather than anaerobic digestion is employed. However, an anaerobic digestion process is favorable over alkaline stabilization, with 35% lower overall natural resource use. The most significant reduction of the resource footprint occurred when the output biogas was valorized in a combined heat and power system.

Review of wildlife resources of Vandenberg Air Force Base, California

NASA Technical Reports Server (NTRS)

Breininger, David R.

1989-01-01

Wildlife resources are reviewed for purposes of developing a Base Biological Monitoring Program (BMP) for Vandenberg Air Force Base (VAFB) in Santa Barbara County, California. The review and recommendations were prepared by review of applicable scientific literature and environmental documents for VAFB, discussing information needs with natural resource management professionals at VAFB, and observations of base field conditions. This process found that there are 29 federally listed vertebrates (endangered, threatened, or Category 2) that occur or may occur in the vicinity of VAFB. There are also 63 other state listed or regionally declining species that may occur in the vicinity of VAFB. Habitats of VAFB represent a very valuable environmental resource for rare and declining wildlife in California. However, little information is available on VAFB wildlife resources other than lists of species that occur or are expected to occur. Recommendations are presented to initiate a long-term wildlife monitoring program at VAFB to provide information for environmental impact assessment and wise land use planning.

Belief inhibition during thinking: not always winning but at least taking part.

PubMed

De Neys, Wim; Franssens, Samuel

2009-10-01

Human thinking is often biased by intuitive beliefs. Inhibition of these tempting beliefs is considered a key component of human thinking, but the process is poorly understood. In the present study we clarify the nature of an inhibition failure and the resulting belief bias by probing the accessibility of cued beliefs after people reasoned. Results indicated that even the poorest reasoners showed an impaired memory access to words that were associated with cued beliefs after solving reasoning problems in which the beliefs conflicted with normative considerations (Experiment 1 and 2). The study further established that the impairment was only temporary in nature (Experiment 3) and did not occur when people were explicitly instructed to give mere intuitive judgments (Experiment 4). Findings present solid evidence for the postulation of an inhibition process and imply that belief bias does not result from a failure to recognize the need to inhibit inappropriate beliefs, but from a failure to complete the inhibition process. This indicates that people are far more logical than hitherto believed.

Electron petrography of silica polymorphs associated with pseudotachylite, Vredefort structure, South Africa

NASA Technical Reports Server (NTRS)

White, J. C.

1992-01-01

High-pressure silica polymorphs (coesite and stishovite) were described from the Vredefort structure in association with pseudotachylite veinlets. In addition to the fundamental significance of the polymorphs to genetic interpretations of the structure, it was additionally argued that the type of pseudotachylite with which they occur forms during the compressional phase of the shock process, while the larger, classic pseudotachylite occurrences are barren of polymorphs and formed during passage of the rarefaction wave. This identification of temporal relationships among transient shock features at a regional scale is similar to observations from the Manicouagan structure, Quebec, where texturally distinct diaplectic plagioclase glasses formed during both compressional and decompressional phases of the shock process. The clarification of such relationships impinges directly on interpretations of natural shock processes and the identification of high probability targets for polymorph searches. Detailed analytical scanning (SEM) and transmission electron microscopy (TEM) were utilized to further establish the nature of both the pseudotachylite and the silica polymorph occurrences in the Vredefort rocks. The results of this investigation are discussed.

Anisotropic etching of platinum electrodes at the onset of cathodic corrosion

PubMed Central

Hersbach, Thomas J. P.; Yanson, Alexei I.; Koper, Marc T. M.

2016-01-01

Cathodic corrosion is a process that etches metal electrodes under cathodic polarization. This process is presumed to occur through anionic metallic reaction intermediates, but the exact nature of these intermediates and the onset potential of their formation is unknown. Here we determine the onset potential of cathodic corrosion on platinum electrodes. Electrodes are characterized electrochemically before and after cathodic polarization in 10 M sodium hydroxide, revealing that changes in the electrode surface start at an electrode potential of −1.3 V versus the normal hydrogen electrode. The value of this onset potential rules out previous hypotheses regarding the nature of cathodic corrosion. Scanning electron microscopy shows the formation of well-defined etch pits with a specific orientation, which match the voltammetric data and indicate a remarkable anisotropy in the cathodic etching process, favouring the creation of (100) sites. Such anisotropy is hypothesized to be due to surface charge-induced adsorption of electrolyte cations. PMID:27554398

Natural Rewards, Neuroplasticity, and Non-Drug Addictions

PubMed Central

Olsen, Christopher M.

2011-01-01

There is a high degree of overlap between brain regions involved in processing natural rewards and drugs of abuse. “Non-drug” or “behavioral” addictions have become increasingly documented in the clinic, and pathologies include compulsive activities such as shopping, eating, exercising, sexual behavior, and gambling. Like drug addiction, non-drug addictions manifest in symptoms including craving, impaired control over the behavior, tolerance, withdrawal, and high rates of relapse. These alterations in behavior suggest that plasticity may be occurring in brain regions associated with drug addiction. In this review, I summarize data demonstrating that exposure to non-drug rewards can alter neural plasticity in regions of the brain that are affected by drugs of abuse. Research suggests that there are several similarities between neuroplasticity induced by natural and drug rewards and that, depending on the reward, repeated exposure to natural rewards might induce neuroplasticity that either promotes or counteracts addictive behavior. PMID:21459101

Neural correlations enable invariant coding and perception of natural stimuli in weakly electric fish

PubMed Central

Metzen, Michael G; Hofmann, Volker; Chacron, Maurice J

2016-01-01

Neural representations of behaviorally relevant stimulus features displaying invariance with respect to different contexts are essential for perception. However, the mechanisms mediating their emergence and subsequent refinement remain poorly understood in general. Here, we demonstrate that correlated neural activity allows for the emergence of an invariant representation of natural communication stimuli that is further refined across successive stages of processing in the weakly electric fish Apteronotus leptorhynchus. Importantly, different patterns of input resulting from the same natural communication stimulus occurring in different contexts all gave rise to similar behavioral responses. Our results thus reveal how a generic neural circuit performs an elegant computation that mediates the emergence and refinement of an invariant neural representation of natural stimuli that most likely constitutes a neural correlate of perception. DOI: http://dx.doi.org/10.7554/eLife.12993.001 PMID:27128376

Controlled Acceleration and Inhibition of Bergman Cyclization by Metal Chlorides

NASA Astrophysics Data System (ADS)

Warner, Benjamin P.; Millar, Susan P.; Broene, Richard D.; Buchwald, Stephen L.

1995-08-01

The Bergman cyclization has been the subject of renewed interest with the discovery of naturally occurring enediyne-based antitumor agents that cleave DNA by means of an aromatic diradical. These natural substrates have a means to trigger this cycloaromatization process. Control of this reaction by substrate modification would allow aromatic diradicals to be generated selectively. In the studies presented here it is disclosed that the Bergman cyclization of 1,2-bis(diphenyl phosphinoethynyl)benzene was accelerated by a factor of >30,000 by the addition of palladium(II) chloride or platinum(II) chloride and was inhibited by the addition of mercury(II) chloride.

Study of cosmic rays reveals secrets of solar-terrestrial science

NASA Astrophysics Data System (ADS)

Jokipii, J. R.

For many years cosmic rays provided the most important source of energetic particles for studies of subatomic physics. Today, cosmic rays are being studied as a natural phenomenon that can tell us much about both the Earth's environment in space and distant astrophysical processes. Cosmic rays are naturally occurring energetic particles—mainly ions—with kinetic energies extending from just above thermal energies to more than 1020 electron volts (eV). They constantly bombard the Earth from all directions, with more than 1018 particles having energies >1 MeV striking the top of the Earth's atmosphere each second. Figure 1 illustrates the continuous cosmic ray energy spectrum.

Effects of hexanal, trans-2-hexenal, and storage temperature on shelf life of fresh sliced apples.

PubMed

Corbo, M R; Lanciotti, R; Gardini, F; Sinigaglia, M; Guerzoni, M E

2000-06-01

In this paper, the effects of hexanal and trans-2-hexenal, which are both natural molecules characterizing apple aroma, on the microbial population and on color retention of fresh sliced apples were evaluated. In particular, a central composite design (CCD) was developed to assess the individual and interactive effects of the chosen volatile molecules and storage temperatures on (i) the growth of the naturally occurring microflora, (ii) the evolution over time of an inoculated spoilage yeast (Pichia subpelliculosa), and (iii) the enzymatic browning reaction in minimally processed apples. The inclusion of hexanal and trans-2-hexenal in the storage atmosphere of apple slices determined a significant extension of shelf life also when P. subpelliculosa was inoculated at levels of 10(3) colony-forming units/g and abusive storage temperatures were used. In fact, the presence of these molecules in the packaging atmospheres considerably prolonged the lag phases of the inoculated yeast and reduced the growth potential of naturally occurring bacteria. Moreover, the addition to the modified atmosphere of low levels of the hexanal increased the color stability of the products up to 16 days.

Effective dose in SMAW and FCAW welding processes using rutile consumables.

PubMed

Herranz, M; Rozas, S; Idoeta, R; Alegría, N

2014-03-01

The shielded metal arc welding (SMAW) and flux cored arc welding (FCAW) processes use covered electrodes and flux cored wire as consumables. Among these consumables, ones containing rutile are the most widely used, and since they have a considerable natural radioactive content, they can be considered as NORM (naturally occurring radioactive material). To calculate the effective dose on workers during their use in a conservative situation, samples of slag and aerosols and particles emitted or deposited during welding were taken and measured by gamma, alpha and beta spectrometry. An analytical method was also developed for estimating the activity concentration of radionuclides in the inhaled air. (222)Rn activity concentration was also assessed. With all these data, internal and external doses were calculated. The results show that external doses are negligible in comparison with internal ones, which do not exceed 1 mSv yr(-1), either in this conservative situation or in any other more favourable one. Radionuclides after Rn in the radioactive natural series are emitted at the same activity concentration to the atmosphere, this being around 17 times higher than that corresponding to radionuclides before Rn. Taking into account these conclusions and the analytical method developed, it can be concluded that one way to assess the activity concentration of natural radionuclides in inhaled air and hence effective doses could be the early gamma-ray spectrometry of aerosols and particles sampled during the welding process.

Fort Collins Science Center Ecosystem Dynamics Branch

USGS Publications Warehouse

Wilson, Jim; Melcher, C.; Bowen, Z.

2009-01-01

Complex natural resource issues require understanding a web of interactions among ecosystem components that are (1) interdisciplinary, encompassing physical, chemical, and biological processes; (2) spatially complex, involving movements of animals, water, and airborne materials across a range of landscapes and jurisdictions; and (3) temporally complex, occurring over days, weeks, or years, sometimes involving response lags to alteration or exhibiting large natural variation. Scientists in the Ecosystem Dynamics Branch of the U.S. Geological Survey, Fort Collins Science Center, investigate a diversity of these complex natural resource questions at the landscape and systems levels. This Fact Sheet describes the work of the Ecosystems Dynamics Branch, which is focused on energy and land use, climate change and long-term integrated assessments, herbivore-ecosystem interactions, fire and post-fire restoration, and environmental flows and river restoration.

Deep sequencing uncovers commonality in small RNA profiles between transgene-induced and naturally occurring RNA silencing of chalcone synthase-A gene in petunia.

PubMed

Kasai, Megumi; Matsumura, Hideo; Yoshida, Kentaro; Terauchi, Ryohei; Taneda, Akito; Kanazawa, Akira

2013-01-30

Introduction of a transgene that transcribes RNA homologous to an endogenous gene in the plant genome can induce silencing of both genes, a phenomenon termed cosuppression. Cosuppression was first discovered in transgenic petunia plants transformed with the CHS-A gene encoding chalcone synthase, in which nonpigmented sectors in flowers or completely white flowers are produced. Some of the flower-color patterns observed in transgenic petunias having CHS-A cosuppression resemble those in existing nontransgenic varieties. Although the mechanism by which white sectors are generated in nontransgenic petunia is known to be due to RNA silencing of the CHS-A gene as in cosuppression, whether the same trigger(s) and/or pattern of RNA degradation are involved in these phenomena has not been known. Here, we addressed this question using deep-sequencing and bioinformatic analyses of small RNAs. We analyzed short interfering RNAs (siRNAs) produced in nonpigmented sectors of petal tissues in transgenic petunia plants that have CHS-A cosuppression and a nontransgenic petunia variety Red Star, that has naturally occurring CHS-A RNA silencing. In both silencing systems, 21-nt and 22-nt siRNAs were the most and the second-most abundant size classes, respectively. CHS-A siRNA production was confined to exon 2, indicating that RNA degradation through the RNA silencing pathway occurred in this exon. Common siRNAs were detected in cosuppression and naturally occurring RNA silencing, and their ranks based on the number of siRNAs in these plants were correlated with each other. Noticeably, highly abundant siRNAs were common in these systems. Phased siRNAs were detected in multiple phases at multiple sites, and some of the ends of the regions that produced phased siRNAs were conserved. The features of siRNA production found to be common to cosuppression and naturally occurring silencing of the CHS-A gene indicate mechanistic similarities between these silencing systems especially in the biosynthetic processes of siRNAs including cleavage of CHS-A transcripts and subsequent production of secondary siRNAs in exon 2. The data also suggest that these events occurred at multiple sites, which can be a feature of these silencing phenomena.

NRL Review, 1994. (Naval Research Lab)

DTIC Science & Technology

1994-03-01

analysis of Brockway (left) at the University of Michigan in gaseous state fluorine and hydrocarbon 1945 compounds . Both she and her husband 10 would later... sorption , desorption, and abstraction processes general, and CVD growth in particular, can create a dynamic balance that leaves some open occur principally...4]. Natural compounds of the inner diameter of the cylinder and the extracted from a number of marine animals and polymeric carrier that may be

What Makes a Social Encounter Meaningful: The Impact of Social Encounters of Homeschooled Children on Emotional and Behavioral Problems

ERIC Educational Resources Information Center

Guterman, Oz; Neuman, Ari

2017-01-01

In modern society, a large part of the socialization process occurs in schools. Therefore, one of the most significant questions raised with regard to homeschooling concerns the impact of this type of education on the emotional world of the child. However, there is almost no mention in the research of how the nature of the social activity of…

Sawflies and ponderosa pine: hypothetical response surfaces for pine genotype, ontogenic stage, and stress level

Treesearch

Michael R. Wagner

1991-01-01

Patterns that occur in nature are the result of a complex set of current and historical factors that interact with one another and the adaptive plasticity of plants. Scientists are forced to assess such processes on the basis of series of "snapshots" over a relatively short time that represent only part of the grand pattern. In the case of insects interacting...

Fire decreases arthropod abundance but increases diversity: early and late season prescribed fire effects in a Sierra Nevada mixed-conifer forest

Treesearch

Scott M. Ferrenberg; Dylan W. Schwilk; Eric E. Knapp; Eric Groth; Jon E. Keeley

2006-01-01

Prior to fire suppression in the 20th century, the mixed-conifer forests of the Sierra Nevada, California, U.S.A., historically burned in frequent fires that typically occurred during the late summer and early fall. Fire managers have been attempting to restore natural ecosystem processes through prescription burning, and have often favored burning during the fall in...

Arsenic, microbes and contaminated aquifers

USGS Publications Warehouse

Oremland, Ronald S.; Stolz, John F.

2005-01-01

The health of tens of millions of people world-wide is at risk from drinking arsenic-contaminated well water. In most cases this arsenic occurs naturally within the sub-surface aquifers, rather than being derived from identifiable point sources of pollution. The mobilization of arsenic into the aqueous phase is the first crucial step in a process that eventually leads to human arsenicosis. Increasing evidence suggests that this is a microbiological phenomenon.

Human, Nature, Dynamism: The Effects of Content and Movement Perception on Brain Activations during the Aesthetic Judgment of Representational Paintings

PubMed Central

Di Dio, Cinzia; Ardizzi, Martina; Massaro, Davide; Di Cesare, Giuseppe; Gilli, Gabriella; Marchetti, Antonella; Gallese, Vittorio

2016-01-01

Movement perception and its role in aesthetic experience have been often studied, within empirical aesthetics, in relation to the human body. No such specificity has been defined in neuroimaging studies with respect to contents lacking a human form. The aim of this work was to explore, through functional magnetic imaging (f MRI), how perceived movement is processed during the aesthetic judgment of paintings using two types of content: human subjects and scenes of nature. Participants, untutored in the arts, were shown the stimuli and asked to make aesthetic judgments. Additionally, they were instructed to observe the paintings and to rate their perceived movement in separate blocks. Observation highlighted spontaneous processes associated with aesthetic experience, whereas movement judgment outlined activations specifically related to movement processing. The ratings recorded during aesthetic judgment revealed that nature scenes received higher scored than human content paintings. The imaging data showed similar activation, relative to baseline, for all stimuli in the three tasks, including activation of occipito-temporal areas, posterior parietal, and premotor cortices. Contrast analyses within aesthetic judgment task showed that human content activated, relative to nature, precuneus, fusiform gyrus, and posterior temporal areas, whose activation was prominent for dynamic human paintings. In contrast, nature scenes activated, relative to human stimuli, occipital and posterior parietal cortex/precuneus, involved in visuospatial exploration and pragmatic coding of movement, as well as central insula. Static nature paintings further activated, relative to dynamic nature stimuli, central and posterior insula. Besides insular activation, which was specific for aesthetic judgment, we found a large overlap in the activation pattern characterizing each stimulus dimension (content and dynamism) across observation, aesthetic judgment, and movement judgment tasks. These findings support the idea that the aesthetic evaluation of artworks depicting both human subjects and nature scenes involves a motor component, and that the associated neural processes occur quite spontaneously in the viewer. Furthermore, considering the functional roles of posterior and central insula, we suggest that nature paintings may evoke aesthetic processes requiring an additional proprioceptive and sensori-motor component implemented by “motor accessibility” to the represented scenario, which is needed to judge the aesthetic value of the observed painting. PMID:26793087

Vincristine modulates the expression of Ki67 and apoptosis in naturally occurring canine transmissible venereal tumor (TVT).

PubMed

Özalp, G R; Zik, B; Bastan, A; Peker, S; Özdemir-Salci, E S; Bastan, I; Darbaz, I; Salar, S; Karakas, K

2012-07-01

We investigated eight adult dogs that were brought to veterinary clinics with a history of transmissible venereal tumors (TVT). Our goal was to demonstrate the occurrence of apoptosis and the cessation of cell proliferation at every phase of scheduled chemotherapy for naturally occurring TVT. Tissue samples were collected immediately after weekly treatments with vincristine sulfate and processed for histological purposes. Sections 5 μm thick were stained by the TUNEL reaction for apoptosis and immunostained for Ki67 as a proliferation marker. We observed that after vincristine applications, tumor cell proliferation ceased and apoptosis increased. Ki67 HSCORE values were significantly lowered after the first and second treatments with the chemotherapeutic agent compared to controls, whereas TUNEL HSCORE values were significantly higher after two applications of vincristine compared to controls. Our results suggest that scheduled vincristine sulfate applications stabilize the induction of tumor regression by inducing apoptosis and preventing cell proliferation.

Molecular Darwinism: The Contingency of Spontaneous Genetic Variation

PubMed Central

Arber, Werner

2011-01-01

The availability of spontaneously occurring genetic variants is an important driving force of biological evolution. Largely thanks to experimental investigations by microbial geneticists, we know today that several different molecular mechanisms contribute to the overall genetic variations. These mechanisms can be assigned to three natural strategies to generate genetic variants: 1) local sequence changes, 2) intragenomic reshuffling of DNA segments, and 3) acquisition of a segment of foreign DNA. In these processes, specific gene products are involved in cooperation with different nongenetic elements. Some genetic variations occur fully at random along the DNA filaments, others rather with a statistical reproducibility, although at many possible sites. We have to be aware that evolution in natural ecosystems is of higher complexity than under most laboratory conditions, not at least in view of symbiotic associations and the occurrence of horizontal gene transfer. The encountered contingency of genetic variation can possibly best ensure a long-term persistence of life under steadily changing living conditions. PMID:21979160

Interprofessional learning, impression management, and spontaneity in the acute healthcare setting.

PubMed

Bell, Elaine; McAllister, Sue; Ward, Paul R; Russell, Alison

2016-09-01

Spontaneous learning is integral to definitions of interprofessional learning (IPL) because it has been suggested that spontaneous learning can be deeply connected with the work that people do in collaboration with colleagues via their professional networks. However, its nature and the processes involved are not well understood. Goffman's theory of impression management offers a useful theoretical framework to consider the way in which interaction in the workplace connects to spontaneous learning. This article explores the current literature to investigate the usefulness of this framework to better understand and identify spontaneous learning in the workplace. Aspects such as the connections between spontaneous learning occurring in formal and informal work activities, the spaces in which it occurs, and the influence of professional networking are considered. It is proposed that research directed to developing a better understanding of the nature of spontaneous learning in IPL will assist in connecting this learning to formal IPL curricula, enhancing IPL and patient outcomes.

Molecular Darwinism: the contingency of spontaneous genetic variation.

PubMed

Arber, Werner

2011-01-01

The availability of spontaneously occurring genetic variants is an important driving force of biological evolution. Largely thanks to experimental investigations by microbial geneticists, we know today that several different molecular mechanisms contribute to the overall genetic variations. These mechanisms can be assigned to three natural strategies to generate genetic variants: 1) local sequence changes, 2) intragenomic reshuffling of DNA segments, and 3) acquisition of a segment of foreign DNA. In these processes, specific gene products are involved in cooperation with different nongenetic elements. Some genetic variations occur fully at random along the DNA filaments, others rather with a statistical reproducibility, although at many possible sites. We have to be aware that evolution in natural ecosystems is of higher complexity than under most laboratory conditions, not at least in view of symbiotic associations and the occurrence of horizontal gene transfer. The encountered contingency of genetic variation can possibly best ensure a long-term persistence of life under steadily changing living conditions.

[National system of protection against electromagnetic fields 0 Hz-300 GHz in the light of current legal regulations].

PubMed

Aniołczyk, Halina

2006-01-01

Exposure to electromagnetic fields (EMF) occurs when man is exposed to the effect of electric, magnetic and electromagnetic fields and contact currents different from those resulting from physiological processes in the organism or other natural phenomena. In Poland, the system of protection against EMF has been functioning for over 35 years. In 2001, when the Minister of Labor and Social Policy issued the regulation introducing the maximum admissible intensities (MAI) for electromagnetic fields and radiation within the range of 0 Hz-300 GHz, the system was directed mainly towards evaluation of exposure to EMF occurring in the occupational environment. The system is linked via MAI values with human protection in the natural environment. In this paper, the background, principles and the range of the national system of protection against EMF and its monitoring are presented. The project of implementation of EU directives, following Poland's accession to the European Union is also discussed.

Trauma or growth after a natural disaster? The mediating role of rumination processes

PubMed Central

García, Felipe E.; Cova, Félix; Rincón, Paulina; Vázquez, Carmelo

2015-01-01

The aim of this study was to test a cognitive model of posttraumatic symptoms (PTS) and posttraumatic growth (PTG) after exposure to a natural disaster. It was hypothesized that although subjective severity of trauma would be related to the severity of PTS, this relation would be mediated by brooding and cognitive strategies related to the presence of repetitive negative content in thoughts. Furthermore, the relation between severity and PTG would be fully mediated by deliberate rumination (DR), cognitive strategies related to conscious efforts focused on handling the event. To evaluate the cognitive model, adults (N=351) who lost their homes as a result of the earthquake and tsunami that occurred in Chile on February 27, 2010, were selected. Structural equation modeling was used to analyze the data. The resulting model had adequate indices of goodness adjustment and showed that brooding completely mediated the relation between subjective severity and PTS, and DR completely mediated the relation between subjective severity, brooding, and PTG. These results highlight the role of both the content and process of rumination in mediating the association between subjective severity of trauma, PTS, and PTG. The implications of these results for a more comprehensive model of symptom severity that occurs after trauma are discussed. PMID:26234365

Long-term evolution of the Luteoviridae: time scale and mode of virus speciation.

PubMed

Pagán, Israel; Holmes, Edward C

2010-06-01

Despite their importance as agents of emerging disease, the time scale and evolutionary processes that shape the appearance of new viral species are largely unknown. To address these issues, we analyzed intra- and interspecific evolutionary processes in the Luteoviridae family of plant RNA viruses. Using the coat protein gene of 12 members of the family, we determined their phylogenetic relationships, rates of nucleotide substitution, times to common ancestry, and patterns of speciation. An associated multigene analysis enabled us to infer the nature of selection pressures and the genomic distribution of recombination events. Although rates of evolutionary change and selection pressures varied among genes and species and were lower in some overlapping gene regions, all fell within the range of those seen in animal RNA viruses. Recombination breakpoints were commonly observed at gene boundaries but less so within genes. Our molecular clock analysis suggested that the origin of the currently circulating Luteoviridae species occurred within the last 4 millennia, with intraspecific genetic diversity arising within the last few hundred years. Speciation within the Luteoviridae may therefore be associated with the expansion of agricultural systems. Finally, our phylogenetic analysis suggested that viral speciation events tended to occur within the same plant host species and country of origin, as expected if speciation is largely sympatric, rather than allopatric, in nature.

Natural Codeswitching Knocks on the Laboratory Door

ERIC Educational Resources Information Center

Myers-Scotton, Carol

2006-01-01

This contribution discusses findings and hypotheses from empirical data of naturally-occurring codeswitching. The discussion is framed by some comparisons of the approaches of contact linguists and psycholinguists to bilingual production data. However, it emphasizes the relevance of naturally-occurring codeswitching to the theoretical questions…

Unravelling a 'miner's myth' that environmental contamination in mining towns is naturally occurring.

PubMed

Kristensen, Louise Jane; Taylor, Mark Patrick

2016-08-01

Australia has a long history of metal mining and smelting. Extraction and processing have resulted in elevated levels of toxic metals surrounding mining operations, which have adverse health effects, particularly to children. Resource companies, government agencies and employees often construct 'myths' to down play potential exposure risks and responsibility arising from operating emissions. Typical statements include: contaminants are naturally occurring, the wind blows emissions away from residential areas, contaminants are not bioavailable, or the problem is a legacy issue and not related to current operations. Evidence from mining and smelting towns shows that such 'myths' are exactly that. In mining towns, the default and primary defence against contamination is that elevated metals in adjacent urban environments are from the erosion and weathering of the ore bodies over millennia-hence 'naturally occurring'. Not only is this a difficult argument to unravel from an evidence-based perspective, but also it causes confusion and delays remediation work, hindering efforts to reduce harmful exposures to children. An example of this situation is from Broken Hill, New South Wales, home to one of the world's largest lead-zinc-silver ore body, which has been mined continuously for over 130 years. Environmental metal concentration and lead isotopic data from soil samples collected from across Broken Hill are used to establish the nature and timing of lead contamination. We use multiple lines of evidence to unravel a 'miner's myth' by evaluating current soil metal concentrations and lead isotopic compositions, geological data, historical environmental assessments and old photographic evidence to assess the impacts from early smelting along with mining to the surface soils in the city.

Physical modeling of the formation and evolution of seismically active fault zones

USGS Publications Warehouse

Ponomarev, A.V.; Zavyalov, A.D.; Smirnov, V.B.; Lockner, D.A.

1997-01-01

Acoustic emission (AE) in rocks is studied as a model of natural seismicity. A special technique for rock loading has been used to help study the processes that control the development of AE during brittle deformation. This technique allows us to extend to hours fault growth which would normally occur very rapidly. In this way, the period of most intense interaction of acoustic events can be studied in detail. Characteristics of the acoustic regime (AR) include the Gutenberg-Richter b-value, spatial distribution of hypocenters with characteristic fractal (correlation) dimension d, Hurst exponent H, and crack concentration parameter Pc. The fractal structure of AR changes with the onset of the drop in differential stress during sample deformation. The change results from the active interaction of microcracks. This transition of the spatial distribution of AE hypocenters is accompanied by a corresponding change in the temporal correlation of events and in the distribution of event amplitudes as signified by a decrease of b-value. The characteristic structure that develops in the low-energy background AE is similar to the sequence of the strongest microfracture events. When the AR fractal structure develops, the variations of d and b are synchronous and d = 3b. This relation which occurs once the fractal structure is formed only holds for average values of d and b. Time variations of d and b are anticorrelated. The degree of temporal correlation of AR has time variations that are similar to d and b variations. The observed variations in laboratory AE experiments are compared with natural seismicity parameters. The close correspondence between laboratory-scale observations and naturally occurring seismicity suggests a possible new approach for understanding the evolution of complex seismicity patterns in nature. ?? 1997 Elsevier Science B.V. All rights reserved.

Evaluation of the male reproductive toxicity of gallium arsenide.

PubMed

Bomhard, Ernst M; Cohen, Samuel M; Gelbke, Heinz-Peter; Williams, Gary M

2012-10-01

Gallium arsenide is an important semiconductor material marketed in the shape of wafers and thus is not hazardous to the end user. Exposure to GaAs particles may, however, occur during manufacture and processing. Potential hazards require evaluation. In 14-week inhalation studies with small GaAs particles, testicular effects have been reported in rats and mice. These effects occurred only in animals whose lungs showed marked inflammation and also had hematologic changes indicating anemia and hemolysis. The time- and concentration-dependent progressive nature of the lung and blood effects together with bioavailability data on gallium and arsenic lead us to conclude that the testicular/sperm effects are secondary to hypoxemia resulting from lung damage rather than due to a direct chemical effect of gallium or arsenide. Conditions leading to such primary effects are not expected to occur in humans at production and processing sites. This has to be taken into consideration for any classification decision for reproductive toxicity; especially a category 1 according to the EU CLP system is not warranted. Copyright © 2012 Elsevier Inc. All rights reserved.

RAGE splicing variants in mammals.

PubMed

Sterenczak, Katharina Anna; Nolte, Ingo; Murua Escobar, Hugo

2013-01-01

The receptor for advanced glycation end products (RAGE) is a multiligand receptor of environmental stressors which plays key roles in pathophysiological processes, including immune/inflammatory disorders, Alzheimer's disease, diabetic arteriosclerosis, tumorigenesis, and metastasis. Besides the full-length RAGE protein in humans nearly 20 natural occurring RAGE splicing variants were described on mRNA and protein level. These naturally occurring isoforms are characterized by either N-terminally or C-terminally truncations and are discussed as possible regulators of the full-length RAGE receptor either by competitive ligand binding or by displacing the full-length protein in the membrane. Accordingly, expression deregulations of the naturally occurring isoforms were supposed to have significant effect on RAGE-mediated disorders. Thereby the soluble C-truncated RAGE isoforms present in plasma and tissues are the mostly focused isoforms in research and clinics. Deregulations of the circulating levels of soluble RAGE forms were reported in several RAGE-associated pathological disorders including for example atherosclerosis, diabetes, renal failure, Alzheimer's disease, and several cancer types. Regarding other mammalian species, the canine RAGE gene showed high similarities to the corresponding human structures indicating RAGE to be evolutionary highly conserved between both species. Similar to humans the canine RAGE showed a complex and extensive splicing activity leading to a manifold pattern of RAGE isoforms. Due to the similarities seen in several canine and human diseases-including cancer-comparative structural and functional analyses allow the development of RAGE and ligand-specific therapeutic approaches beneficial for human and veterinary medicine.

A functional-oriented assessment of environmental criticality due to anthropic actions along the hillslopes of the Somma-Vesuvio volcano (Naples, Italy).

NASA Astrophysics Data System (ADS)

Romano, Nunzio; De Falco, Melania; Speranza, Giuseppe; Tarolli, Paolo

2015-04-01

Mediterranean environments are characterized by a climatic regime with a strong seasonal variability. More uniform precipitations usually occur during the winter season, whereas short and very intense rainfalls occur during the fall and early spring that, in turn, trigger surface runoff and severe soil erosion phenomena. When this typical seasonality interacts with a territory substantially altered by anthropic actions, conditions can easily arise for environmental imbalances with serious risks for flash floods and landslides. Many of the degradation dynamics recorded during the last decades in western countries are also the result of the socio-economic changes after the II world war which yielded land-use changes with the urban sprawl process and the increase in human settlements of the natural environments. We are also witnessing a change in the perception of the natural environment and the relevant values. This study benefits from the availability of historical maps and rainfall time series to analyze the profound landscape changes occurred during the last century along the hillsides of the Somma-Vesuvio volcano, in the renowned piedmont area located at east of Napoli city. We are specifically interested in the changes and disturbances made to the hydrographic network to evaluate the increasing potential risks for flood and landslides along these hillslopes characterized by the presence of highly vulnerable volcanic soils, the construction of roads, and other negative alterations of the natural overland flow patterns.

Natural attenuation of NDMA precursors in an urban, wastewater-dominated wash.

PubMed

Woods, Gwen C; Dickenson, Eric R V

2016-02-01

N-Nitrosodimethylamine (NDMA) is a disinfection by-product (DBP) that is potentially carcinogenic and has been found to occur in drinking water treatment systems impacted with treated wastewater. A major gap in NDMA research is an understanding of the persistence of wastewater-derived precursors within the natural environment. This research sought to fill this knowledge gap by surveying NDMA precursors across the length of a wastewater effluent-dominated wash. Significant precursor reduction (17%) was found to occur from introduction into the wash to a point 9 h downstream. This reduction translates into a half-life of roughly 32 h for bulk NDMA precursors. Further laboratory experiments examining rates of photolysis, biodegradation and loss to sediments, illustrated that both photolytic and biological degradation were effective removal mechanisms for NDMA precursors. Loss to sediments that were acquired from the wash did not appear to reduce NDMA precursors in the water column, although a control conducted with DI water provided evidence that significant NDMA precursors could be released from autoclaved sediments (suggesting that sorption does occur). Microbial experiments revealed that microbes associated with sediments were much more effective at degrading precursors than microbes within the water column. Overall, this study demonstrated that natural processes are capable of attenuating NDMA precursors relatively quickly within the environment, and that utilities might benefit from maximizing source water residency time in the environment, prior to introduction into treatment plants. Copyright © 2015 Elsevier Ltd. All rights reserved.

The Naturally Occurring Compound Garcinia Indica Selectively Impairs the Reconsolidation of a Cocaine-Associated Memory.

PubMed

Monsey, Melissa S; Sanchez, Hayde; Taylor, Jane R

2017-02-01

Sustained abstinence from cocaine use is frequently compromised by exposure to environmental stimuli that have previously been strongly associated with drug taking. Such cues trigger memories of the effects of the drug, leading to craving and potential relapse. Our work has demonstrated that manipulating cocaine-cue memories by destabilizing them through interfering with the reconsolidation process is one potential therapeutic tool by which to prolong abstinence. Here, we examine the use of the naturally occurring amnestic agent garcinol to manipulate an established cocaine-cue memory. Rats underwent 12 days of cocaine self-administration training during which time active lever presses resulted in an i.v. infusion of cocaine that was paired with a light/tone cue. Next rats underwent lever extinction for 8 days followed by light/tone reactivation and a test of cue-induced cocaine-seeking behavior. Systemic injection of garcinol 30 min after reactivation significantly impaired the reconsolidation of the cocaine-associated cue memory. Further testing revealed that garcinol had no effect on drug-induced cocaine-seeking, but was capable of blocking the initial conditioned reinforcing properties of the cue and prevents the acquisition of a new response. Additional experiments showed that the effects of garcinol are specific to reactivated memories only, temporally constrained, cue-specific, long-lasting, and persist following extended cocaine access. These data provide strong evidence that the naturally occurring compound, garcinol, may be a potentially useful tool to sustain abstinence from drug abuse.

The Naturally Occurring Compound Garcinia Indica Selectively Impairs the Reconsolidation of a Cocaine-Associated Memory

PubMed Central

Monsey, Melissa S; Sanchez, Hayde; Taylor, Jane R

2017-01-01

Sustained abstinence from cocaine use is frequently compromised by exposure to environmental stimuli that have previously been strongly associated with drug taking. Such cues trigger memories of the effects of the drug, leading to craving and potential relapse. Our work has demonstrated that manipulating cocaine-cue memories by destabilizing them through interfering with the reconsolidation process is one potential therapeutic tool by which to prolong abstinence. Here, we examine the use of the naturally occurring amnestic agent garcinol to manipulate an established cocaine-cue memory. Rats underwent 12 days of cocaine self-administration training during which time active lever presses resulted in an i.v. infusion of cocaine that was paired with a light/tone cue. Next rats underwent lever extinction for 8 days followed by light/tone reactivation and a test of cue-induced cocaine-seeking behavior. Systemic injection of garcinol 30 min after reactivation significantly impaired the reconsolidation of the cocaine-associated cue memory. Further testing revealed that garcinol had no effect on drug-induced cocaine-seeking, but was capable of blocking the initial conditioned reinforcing properties of the cue and prevents the acquisition of a new response. Additional experiments showed that the effects of garcinol are specific to reactivated memories only, temporally constrained, cue-specific, long-lasting, and persist following extended cocaine access. These data provide strong evidence that the naturally occurring compound, garcinol, may be a potentially useful tool to sustain abstinence from drug abuse. PMID:27380937

Supernova Explosions, Nucleosynthesis, and Cosmic Chemical Evolution

NASA Astrophysics Data System (ADS)

Truran, James W.

2006-08-01

The Universe emerged from its first three minutes with a composition consisting of hydrogen, deuterium, 3He, 4He, and 7Li. These isotopes constitute the primordial compositions of galaxies. Within galaxies, the synthesis of heavier elements from carbon through uranium is understood to occur during the normal evolution of stars and in supernova explosions of Types I and II. This history is written in the compositions of the stars and gas in our Milky Way Galaxy and other galaxies. The contributions both from massive stars (M>10 Msolar) and associated Type II supernovae and from Type Ia (thermonuclear) supernovae are particularly noteworthy. We review both the nuclear processes by which this occurs and the compositions of the stellar components of our Galaxy as a function of time which reflect these nucleosynthesis processes. We then discuss how such observations inform us of the nature of the earliest stellar populations and of the abundance history of the Cosmos.

Inter-species activity correlations reveal functional correspondences between monkey and human brain areas

PubMed Central

Mantini, Dante; Hasson, Uri; Betti, Viviana; Perrucci, Mauro G.; Romani, Gian Luca; Corbetta, Maurizio; Orban, Guy A.; Vanduffel, Wim

2012-01-01

Evolution-driven functional changes in the primate brain are typically assessed by aligning monkey and human activation maps using cortical surface expansion models. These models use putative homologous areas as registration landmarks, assuming they are functionally correspondent. In cases where functional changes have occurred in an area, this assumption prohibits to reveal whether other areas may have assumed lost functions. Here we describe a method to examine functional correspondences across species. Without making spatial assumptions, we assess similarities in sensory-driven functional magnetic resonance imaging responses between monkey (Macaca mulatta) and human brain areas by means of temporal correlation. Using natural vision data, we reveal regions for which functional processing has shifted to topologically divergent locations during evolution. We conclude that substantial evolution-driven functional reorganizations have occurred, not always consistent with cortical expansion processes. This novel framework for evaluating changes in functional architecture is crucial to building more accurate evolutionary models. PMID:22306809

Metal-silicate fractionation in the surface dust layers of accreting planetesimals: Implications for the formation of ordinary chondrites and the nature of asteroid surfaces

NASA Astrophysics Data System (ADS)

Huang, Shaoxiong; Akridge, Glen; Sears, Derek W. G.

Some of the most primitive solar system materials available for study in the laboratory are the ordinary chondrites, the largest meteorite class. The size and distribution of the chondrules (silicate beads) and metal, which leads to the definition of the H, L, and LL classes, suggest sorting before or during aggregation. We suggest that meteorite parent bodies (probably asteroids) had thick dusty surfaces during their early evolution that were easily mobilized by gases evolving from their interiors. Density and size sorting would have occurred in the surface layers as the upward drag forces of the gases (mainly water) acted against the downward force of gravity. The process is analogous to the industrially important process of fluidization and sorting in pyroclastic volcanics. We calculate that gas flow velocities and gas fluxes for the regolith of an asteroid-sized object heated by the impact of accreting objects or by 26Al would have been sufficient for fluidization. It can also explain, quantitatively in some cases, the observed metal-silicate sorting of ordinary chondrites, which has long been ascribed to processes occurring in the primordial solar nebula. Formation of the chondrites in the thick dynamic regolith is consistent with the major properties of chondritic meteorites (i.e., redox state, petrologic type, cooling rate, matrix abundance). These ideas have implications for the nature of asteroid surfaces and the virtual lack of asteroids with ordinary chondrite-like surfaces.

DHX9 helicase is involved in preventing genomic instability induced by alternatively structured DNA in human cells

PubMed Central

Jain, Aklank; Bacolla, Albino; del Mundo, Imee M.; Zhao, Junhua; Wang, Guliang; Vasquez, Karen M.

2013-01-01

Sequences that have the capacity to adopt alternative (i.e. non-B) DNA structures in the human genome have been implicated in stimulating genomic instability. Previously, we found that a naturally occurring intra-molecular triplex (H-DNA) caused genetic instability in mammals largely in the form of DNA double-strand breaks. Thus, it is of interest to determine the mechanism(s) involved in processing H-DNA. Recently, we demonstrated that human DHX9 helicase preferentially unwinds inter-molecular triplex DNA in vitro. Herein, we used a mutation-reporter system containing H-DNA to examine the relevance of DHX9 activity on naturally occurring H-DNA structures in human cells. We found that H-DNA significantly increased mutagenesis in small-interfering siRNA-treated, DHX9-depleted cells, affecting mostly deletions. Moreover, DHX9 associated with H-DNA in the context of supercoiled plasmids. To further investigate the role of DHX9 in the recognition/processing of H-DNA, we performed binding assays in vitro and chromatin immunoprecipitation assays in U2OS cells. DHX9 recognized H-DNA, as evidenced by its binding to the H-DNA structure and enrichment at the H-DNA region compared with a control region in human cells. These composite data implicate DHX9 in processing H-DNA structures in vivo and support its role in the overall maintenance of genomic stability at sites of alternatively structured DNA. PMID:24049074

DHX9 helicase is involved in preventing genomic instability induced by alternatively structured DNA in human cells.

PubMed

Jain, Aklank; Bacolla, Albino; Del Mundo, Imee M; Zhao, Junhua; Wang, Guliang; Vasquez, Karen M

2013-12-01

Sequences that have the capacity to adopt alternative (i.e. non-B) DNA structures in the human genome have been implicated in stimulating genomic instability. Previously, we found that a naturally occurring intra-molecular triplex (H-DNA) caused genetic instability in mammals largely in the form of DNA double-strand breaks. Thus, it is of interest to determine the mechanism(s) involved in processing H-DNA. Recently, we demonstrated that human DHX9 helicase preferentially unwinds inter-molecular triplex DNA in vitro. Herein, we used a mutation-reporter system containing H-DNA to examine the relevance of DHX9 activity on naturally occurring H-DNA structures in human cells. We found that H-DNA significantly increased mutagenesis in small-interfering siRNA-treated, DHX9-depleted cells, affecting mostly deletions. Moreover, DHX9 associated with H-DNA in the context of supercoiled plasmids. To further investigate the role of DHX9 in the recognition/processing of H-DNA, we performed binding assays in vitro and chromatin immunoprecipitation assays in U2OS cells. DHX9 recognized H-DNA, as evidenced by its binding to the H-DNA structure and enrichment at the H-DNA region compared with a control region in human cells. These composite data implicate DHX9 in processing H-DNA structures in vivo and support its role in the overall maintenance of genomic stability at sites of alternatively structured DNA.

Memory for color reactivates color processing region.

PubMed

Slotnick, Scott D

2009-11-25

Memory is thought to be constructive in nature, where features processed in different cortical regions are synthesized during retrieval. In an effort to support this constructive memory framework, the present functional magnetic resonance imaging study assessed whether memory for color reactivated color processing regions. During encoding, participants were presented with colored and gray abstract shapes. During retrieval, old and new shapes were presented in gray and participants responded 'old-colored', 'old-gray', or 'new'. Within color perception regions, color memory related activity was observed in the left fusiform gyrus, adjacent to the collateral sulcus. A retinotopic mapping analysis indicated this activity occurred within color processing region V8. The present feature specific evidence provides compelling support for a constructive view of memory.

Nonparametric Inference of Doubly Stochastic Poisson Process Data via the Kernel Method

PubMed Central

Zhang, Tingting; Kou, S. C.

2010-01-01

Doubly stochastic Poisson processes, also known as the Cox processes, frequently occur in various scientific fields. In this article, motivated primarily by analyzing Cox process data in biophysics, we propose a nonparametric kernel-based inference method. We conduct a detailed study, including an asymptotic analysis, of the proposed method, and provide guidelines for its practical use, introducing a fast and stable regression method for bandwidth selection. We apply our method to real photon arrival data from recent single-molecule biophysical experiments, investigating proteins' conformational dynamics. Our result shows that conformational fluctuation is widely present in protein systems, and that the fluctuation covers a broad range of time scales, highlighting the dynamic and complex nature of proteins' structure. PMID:21258615

Nonparametric Inference of Doubly Stochastic Poisson Process Data via the Kernel Method.

PubMed

Zhang, Tingting; Kou, S C

2010-01-01

Doubly stochastic Poisson processes, also known as the Cox processes, frequently occur in various scientific fields. In this article, motivated primarily by analyzing Cox process data in biophysics, we propose a nonparametric kernel-based inference method. We conduct a detailed study, including an asymptotic analysis, of the proposed method, and provide guidelines for its practical use, introducing a fast and stable regression method for bandwidth selection. We apply our method to real photon arrival data from recent single-molecule biophysical experiments, investigating proteins' conformational dynamics. Our result shows that conformational fluctuation is widely present in protein systems, and that the fluctuation covers a broad range of time scales, highlighting the dynamic and complex nature of proteins' structure.

7 CFR 766.52 - Eligibility.

Code of Federal Regulations, 2012 CFR

2012-01-01

... borrower's actual production, income and expense records for the year the natural disaster occurred; (ii... expenses incurred because of the natural disaster. (5) For the next production cycle, the borrower must... special servicing action under this part to the loan since the natural disaster occurred. (5) For any loan...

7 CFR 766.52 - Eligibility.

Code of Federal Regulations, 2011 CFR

2011-01-01

... borrower's actual production, income and expense records for the year the natural disaster occurred; (ii... expenses incurred because of the natural disaster. (5) For the next production cycle, the borrower must... special servicing action under this part to the loan since the natural disaster occurred. (5) For any loan...

7 CFR 766.52 - Eligibility.

Code of Federal Regulations, 2014 CFR

2014-01-01

... borrower's actual production, income and expense records for the year the natural disaster occurred; (ii... expenses incurred because of the natural disaster. (5) For the next production cycle, the borrower must... special servicing action under this part to the loan since the natural disaster occurred. (5) For any loan...

7 CFR 766.52 - Eligibility.

Code of Federal Regulations, 2010 CFR

2010-01-01

... borrower's actual production, income and expense records for the year the natural disaster occurred; (ii... expenses incurred because of the natural disaster. (5) For the next production cycle, the borrower must... special servicing action under this part to the loan since the natural disaster occurred. (5) For any loan...

7 CFR 766.52 - Eligibility.

Code of Federal Regulations, 2013 CFR

2013-01-01

... borrower's actual production, income and expense records for the year the natural disaster occurred; (ii... expenses incurred because of the natural disaster. (5) For the next production cycle, the borrower must... special servicing action under this part to the loan since the natural disaster occurred. (5) For any loan...

Rotation Reveals the Importance of Configural Cues in Handwritten Word Perception

PubMed Central

Barnhart, Anthony S.; Goldinger, Stephen D.

2013-01-01

A dramatic perceptual asymmetry occurs when handwritten words are rotated 90° in either direction. Those rotated in a direction consistent with their natural tilt (typically clockwise) become much more difficult to recognize, relative to those rotated in the opposite direction. In Experiment 1, we compared computer-printed and handwritten words, all equated for degrees of leftward and rightward tilt, and verified the phenomenon: The effect of rotation was far larger for cursive words, especially when rotated in a tilt-consistent direction. In Experiment 2, we replicated this pattern with all items presented in visual noise. In both experiments, word frequency effects were larger for computer-printed words and did not interact with rotation. The results suggest that handwritten word perception requires greater configural processing, relative to computer print, because handwritten letters are variable and ambiguous. When words are rotated, configural processing suffers, particularly when rotation exaggerates natural tilt. Our account is similar to theories of the “Thatcher Illusion,” wherein face inversion disrupts holistic processing. Together, the findings suggest that configural, word-level processing automatically increases when people read handwriting, as letter-level processing becomes less reliable. PMID:23589201

Nature or petrochemistry?-biologically degradable materials.

PubMed

Mecking, Stefan

2004-02-20

Naturally occurring polymers have been utilized for a long time as materials, however, their application as plastics has been restricted because of their limited thermoplastic processability. Recently, the microbial synthesis of polyesters directly from carbohydrate sources has attracted considerable attention. The industrial-scale production of poly(lactic acid) from lactic acid generated by fermentation now provides a renewable resources-based polyester as a commodity plastic for the first time. The biodegradability of a given material is independent of its origin, and biodegradable plastics can equally well be prepared from fossil fuel feedstocks. A consideration of the overall carbon dioxide emissions and consumption of non-renewable resources over the entire life-cycle of a product is not necessarily favorable for plastics based on renewable resources with current technology-in addition to the feedstocks for the synthesis of the polymer materials, the feedstock for generation of the overall energy required for production and processing is decisive.

Nature and origin of mineral coatings on volcanic rocks of the Black Mountain, Stonewall Mountain and Kane Springs Wash volcanic centers, southern Nevada

NASA Technical Reports Server (NTRS)

Taranik, J. V.; Noble, D. C.; Hsu, L. C.; Hutsinpiller, A.; Spatz, D.

1986-01-01

Surface coatings on volcanic rock assemblages that occur at select tertiary volcanic centers in southern Nevada were investigated using LANDSAT 5 Thematic Mapper imagery. Three project sites comprise the subject of this study: the Kane Springs Wash, Black Mountain, and Stonewall Mountain volcanic centers. LANDSAT 5 TM work scenes selected for each area are outlined along with local area geology. The nature and composition of surface coatings on the rock types within the subproject areas are determined, along with the origin of the coatings and their genetic link to host rocks, geologic interpretations are related to remote sensing units discriminated on TM imagery. Image processing was done using an ESL VAX/IDIMS image processing system, field sampling, and observation. Aerial photographs were acquired to facilitate location on the ground and to aid stratigraphic differentiation.

Acidity, oxophilicity and hydrogen sticking probability of supported metal catalysts for hydrodeoxygenation process

NASA Astrophysics Data System (ADS)

Lup, A. Ng K.; Abnisa, F.; Daud, W. M. A. W.; Aroua, M. K.

2018-03-01

Hydrodeoxygenation is an oxygen removal process that occurs in the presence of hydrogen and catalysts. This study has shown the importance of acidity, oxophilicity and hydrogen sticking probability of supported metal catalysts in having high hydrodeoxygenation activity and selectivity. These properties are required to ensure the catalyst has high affinity for C-O or C=O bonds and the capability for the adsorption and activation of H2 and O-containing compounds. A theoretical framework of temperature programmed desorption technique was also discussed for the quantitative understanding of these properties. By using NH3-TPD, the nature and abundance of acid sites of catalyst can be determined. By using H2-TPD, the nature and abundance of metallic sites can also be determined. The desorption activation energy could also be determined based on the Redhead analysis of TPD spectra with different heating rates.

Enrichment scale determines herbivore control of primary producers.

PubMed

Gil, Michael A; Jiao, Jing; Osenberg, Craig W

2016-03-01

Anthropogenic nutrient enrichment stimulates primary production and threatens natural communities worldwide. Herbivores may counteract deleterious effects of enrichment by increasing their consumption of primary producers. However, field tests of herbivore control are often done by adding nutrients at small (e.g., sub-meter) scales, while enrichment in real systems often occurs at much larger scales (e.g., kilometers). Therefore, experimental results may be driven by processes that are not relevant at larger scales. Using a mathematical model, we show that herbivores can control primary producer biomass in experiments by concentrating their foraging in small enriched plots; however, at larger, realistic scales, the same mechanism may not lead to herbivore control of primary producers. Instead, other demographic mechanisms are required, but these are not examined in most field studies (and may not operate in many systems). This mismatch between experiments and natural processes suggests that many ecosystems may be less resilient to degradation via enrichment than previously believed.

Lay health advisor activity levels: definitions from the field.

PubMed

Altpeter, M; Earp, J A; Bishop, C; Eng, E

1999-08-01

One type of lay health advisor model assumes that an effective mechanism for reaching the underserved is through informal advice-givers called natural helpers. Despite the growing use of this approach, few programs have defined what an active lay health advisor does within the natural helping process. To explore perceptions and definitions of lay health advisors' activity, we conducted semistructured, in-person interviews with four field staff who coordinate the advisors' activities in a breast cancer screening program. These staff viewed lay health advisor activity as fluctuating over the course of a year, occurring along a continuum of participation (inactive, moderately active, active, and superactive), and reflecting varying degrees of proactivity and participation in multiple activities. These results suggest an empirical process for refining the definition of an active lay health advisor, improving advisors' productivity in achieving outreach objectives, and managing and monitoring their ongoing activities.

Wolves will not provide small-scale ecological restoration

USGS Publications Warehouse

Belant, Jerrold L.; Adams, Layne G.

2010-01-01

Licht and colleagues (BioScience 60: 147–153) proposed a paradigm shift in wolf management to include the introductions of small, highly manipulated groups of wolves (Canis lupus) to confined natural areas to facilitate ecosystem recovery. Certainly, reductions or losses of apex predators from many regions worldwide have had profound effects on ecosystem characteristics (Soulé et al. 2003). Numerous efforts to restore or enhance predator populations through policy change or reintroductions have occurred, often with the intent to restore ecosystem function (Breitenmoser et al. 2001). However, in addition to the gargantuan technological and political challenges inherent in Licht and colleagues' proposal, we contend that intensively managed wolves will not restore natural ecosystem processes given the disparity in scale between these proposed actions and the ecosystem processes that wolves foster. Further, we note that predator-prey relationships are more complex than Licht suggested.

Prediction of vapour-liquid and vapour-liquid-liquid equilibria of nitrogen-hydrocarbon mixtures used in J-T refrigerators

NASA Astrophysics Data System (ADS)

Narayanan, Vineed; Venkatarathnam, G.

2018-03-01

Nitrogen-hydrocarbon mixtures are widely used as refrigerants in J-T refrigerators operating with mixtures, as well as in natural gas liquefiers. The Peng-Robinson equation of state has traditionally been used to simulate the above cryogenic process. Multi parameter Helmholtz energy equations are now preferred for determining the properties of natural gas. They have, however, been used only to predict vapour-liquid equilibria, and not vapour-liquid-liquid equilibria that can occur in mixtures used in cryogenic mixed refrigerant processes. In this paper the vapour-liquid equilibrium of binary mixtures of nitrogen-methane, nitrogen-ethane, nitrogen-propane, nitrogen-isobutane and three component mixtures of nitrogen-methane-ethane and nitrogen-methane-propane have been studied with the Peng-Robinson and the Helmholtz energy equations of state of NIST REFPROP and compared with experimental data available in the literature.

Analysis in natural time domain of geoelectric time series monitored prior two strong earthquakes occurred in Mexico

NASA Astrophysics Data System (ADS)

Ramírez-Rojas, A.; Flores-Marquez, L. E.

2009-12-01

The short-time prediction of seismic phenomena is currently an important problem in the scientific community. In particular, the electromagnetic processes associated with seismic events take in great interest since the VAN method was implemented. The most important features of this methodology are the seismic electrical signals (SES) observed prior to strong earthquakes. SES has been observed in the electromagnetic series linked to EQs in Greece, Japan and Mexico. By mean of the so-called natural time domain, introduced by Varotsos et al. (2001), they could characterize signals of dichotomic nature observed in different systems, like SES and ionic current fluctuations in membrane channels. In this work we analyze SES observed in geoelectric time series monitored in Guerrero, México. Our analysis concern with two strong earthquakes occurred, on October 24, 1993 (M=6.6) and September 14, 1995 (M=7.3). The time series of the first one displayed a seismic electric signal six days before the main shock and for the second case the time series displayed dichotomous-like fluctuations some months before the EQ. In this work we present the first results of the analysis in natural time domain for the two cases which seems to be agreeing with the results reported by Varotsos. P. Varotsos, N. Sarlis, and E. Skordas, Practica of the Athens Academy 76, 388 (2001).

Effects of titanomagnetite reordering processes on thermal demagnetization and paleointensity experiments

NASA Astrophysics Data System (ADS)

Bowles, Julie A.; Jackson, Mike J.

2016-12-01

Titanomagnetite (Fe3-xTixO4, 0 ≤ x ≤ 1) is a common, naturally occurring magnetic mineral critical to many paleomagnetic studies. Underlying most interpretations is the assumption that, lacking chemical alteration, Curie temperature (Tc) remains constant. However, recent work has demonstrated that Tc of many natural titanomagnetites varies strongly as a function of thermal history, independent of chemical alteration. This is inferred to arise from reordering of cations and/or vacancies in the crystal structure, and changes occur at temperatures and times relevant to standard paleomagnetic thermal treatments. Because changes take place at T < Tc, they have the potential to dramatically affect thermal remanence acquisition or demagnetization, impacting interpretation of paleomagnetic results. Here we have modeled the effects of reordering on standard thermal demagnetization and paleointensity experiments. Results suggest that Tc changes during laboratory heating make it impossible to accurately measure the unblocking temperature spectrum without modifying it. Samples with a starting Tc0 less than the closure temperature (Tclose) for the reordering process will develop a high-temperature "tail" that did not exist prior to heating. Samples with a starting Tc0 > Tclose will have their original Tb spectrum truncated at T ≈ Tclose. Predicted behavior during Thellier-type paleointensity experiments results in only modest deviations in NRM-lost or pTRM*-gained from the nonreordering case. Much larger deviations are predicted for pTRM checks. Compared to paleointensity results from titanomagnetite-bearing pyroclastic deposits, modeled nonideal behavior occurs in the same temperature intervals, but is much more systematic. Reordering is likely one contributing factor to failure of paleointensity experiments.

The contribution of visual areas to speech comprehension: a PET study in cochlear implants patients and normal-hearing subjects.

PubMed

Giraud, Anne Lise; Truy, Eric

2002-01-01

Early visual cortex can be recruited by meaningful sounds in the absence of visual information. This occurs in particular in cochlear implant (CI) patients whose dependency on visual cues in speech comprehension is increased. Such cross-modal interaction mirrors the response of early auditory cortex to mouth movements (speech reading) and may reflect the natural expectancy of the visual counterpart of sounds, lip movements. Here we pursue the hypothesis that visual activations occur specifically in response to meaningful sounds. We performed PET in both CI patients and controls, while subjects listened either to their native language or to a completely unknown language. A recruitment of early visual cortex, the left posterior inferior temporal gyrus (ITG) and the left superior parietal cortex was observed in both groups. While no further activation occurred in the group of normal-hearing subjects, CI patients additionally recruited the right perirhinal/fusiform and mid-fusiform, the right temporo-occipito-parietal (TOP) junction and the left inferior prefrontal cortex (LIPF, Broca's area). This study confirms a participation of visual cortical areas in semantic processing of speech sounds. Observation of early visual activation in normal-hearing subjects shows that auditory-to-visual cross-modal effects can also be recruited under natural hearing conditions. In cochlear implant patients, speech activates the mid-fusiform gyrus in the vicinity of the so-called face area. This suggests that specific cross-modal interaction involving advanced stages in the visual processing hierarchy develops after cochlear implantation and may be the correlate of increased usage of lip-reading.

Molecular regulators of resolution of inflammation: potential therapeutic targets in the reproductive system.

PubMed

Hutchinson, James L; Rajagopal, Shalini P; Sales, Kurt J; Jabbour, Henry N

2011-07-01

Inflammatory processes are central to reproductive events including ovulation, menstruation, implantation and labour, while inflammatory dysregulation is a feature of numerous reproductive pathologies. In recent years, there has been much research into the endogenous mechanisms by which inflammatory reactions are terminated and tissue homoeostasis is restored, a process termed resolution. The identification and characterisation of naturally occurring pro-resolution mediators including lipoxins and annexin A1 has prompted a shift in the field of anti-inflammation whereby resolution is now observed as an active process, triggered as part of a normal inflammatory response. This review will address the process of resolution, discuss available evidence for expression of pro-resolution factors in the reproductive tract and explore possible roles for resolution in physiological reproductive processes and associated pathologies.

Environmental Regulation of Microbial Community Structure

NASA Technical Reports Server (NTRS)

Bebout, Leslie; DesMarais, D.; Heyenga, G.; Nelson, F.; DeVincenzi, D. (Technical Monitor)

2002-01-01

Most naturally occurring microbes live in complex microbial communities consisting of thousands of phylotypes of microorganisms living in close proximity. Each of these draws nutrients from the environment and releases metabolic waste products, which may in turn serve as substrates for other microbial groups. Gross environmental changes, such as irradiance level, hydrodynamic flow regime, temperature or water chemistry can directly affect the productivity of some community members, which in turn will affect other dependent microbial populations and rate processes. As a first step towards the development of "standard" natural communities of microorganisms for a variety of potential NASA applications, we are measuring biogeochemical cycling in artificially structured communities of microorganisms, created using natural microbial mat communities as inoculum. The responses of these artificially assembled communities of microorganisms to controlled shifts in ecosystem incubation conditions is being determined. This research requires close linking of environmental monitoring, with community composition in a closed and controlled incubation setting. We are developing new incubation chamber designs to allow for this integrated approach to examine the interplay between environmental conditions, microbial community composition and biogeochemical processes.

Mitigation of Prion Infectivity and Conversion Capacity by a Simulated Natural Process—Repeated Cycles of Drying and Wetting

PubMed Central

Yuan, Qi; Eckland, Thomas; Telling, Glenn; Bartz, Jason; Bartelt-Hunt, Shannon

2015-01-01

Prions enter the environment from infected hosts, bind to a wide range of soil and soil minerals, and remain highly infectious. Environmental sources of prions almost certainly contribute to the transmission of chronic wasting disease in cervids and scrapie in sheep and goats. While much is known about the introduction of prions into the environment and their interaction with soil, relatively little is known about prion degradation and inactivation by natural environmental processes. In this study, we examined the effect of repeated cycles of drying and wetting on prion fitness and determined that 10 cycles of repeated drying and wetting could reduce PrPSc abundance, PMCA amplification efficiency and extend the incubation period of disease. Importantly, prions bound to soil were more susceptible to inactivation by repeated cycles of drying and wetting compared to unbound prions, a result which may be due to conformational changes in soil-bound PrPSc or consolidation of the bonding between PrPSc and soil. This novel finding demonstrates that naturally-occurring environmental process can degrade prions. PMID:25665187

Impact-induced shock and the formation of natural quasicrystals in the early solar system

NASA Astrophysics Data System (ADS)

Hollister, Lincoln S.; Bindi, Luca; Yao, Nan; Poirier, Gerald R.; Andronicos, Christopher L.; MacPherson, Glenn J.; Lin, Chaney; Distler, Vadim V.; Eddy, Michael P.; Kostin, Alexander; Kryachko, Valery; Steinhardt, William M.; Yudovskaya, Marina; Eiler, John M.; Guan, Yunbin; Clarke, Jamil J.; Steinhardt, Paul J.

2014-06-01

The discovery of a natural quasicrystal, icosahedrite (Al63Cu24Fe13), accompanied by khatyrkite (CuAl2) and cupalite (CuAl) in the CV3 carbonaceous chondrite Khatyrka has posed a mystery as to what extraterrestrial processes led to the formation and preservation of these metal alloys. Here we present a range of evidence, including the discovery of high-pressure phases never observed before in a CV3 chondrite, indicating that an impact shock generated a heterogeneous distribution of pressures and temperatures in which some portions reached at least 5 GPa and 1,200 °C. The conditions were sufficient to melt Al-Cu-bearing minerals, which then rapidly solidified into icosahedrite and other Al-Cu metal phases. The meteorite also contains heretofore unobserved phases of iron-nickel and iron sulphide with substantial amounts of Al and Cu. The presence of these phases in Khatyrka provides further proof that the Al-Cu alloys are natural products of unusual processes that occurred in the early solar system.

Logical Form as a Determinant of Cognitive Processes

NASA Astrophysics Data System (ADS)

van Lambalgen, Michiel

We discuss a research program on reasoning patterns in subjects with autism, showing that they fail to engage in certain forms of non-monotonic reasoning that come naturally to neurotypical subjects. The striking reasoning patterns of autists occur both in verbal and in non-verbal tasks. Upon formalising the relevant non-verbal tasks, one sees that their logical form is the same as that of the verbal tasks. This suggests that logical form can play a causal role in cognitive processes, and we suggest that this logical form is actually embodied in the cognitive capacity called 'executive function'.

Capillary absorption spectrometer and process for isotopic analysis of small samples

DOEpatents

Alexander, M. Lizabeth; Kelly, James F.; Sams, Robert L.; Moran, James J.; Newburn, Matthew K.; Blake, Thomas A.

2016-03-29

A capillary absorption spectrometer and process are described that provide highly sensitive and accurate stable absorption measurements of analytes in a sample gas that may include isotopologues of carbon and oxygen obtained from gas and biological samples. It further provides isotopic images of microbial communities that allow tracking of nutrients at the single cell level. It further targets naturally occurring variations in carbon and oxygen isotopes that avoids need for expensive isotopically labeled mixtures which allows study of samples taken from the field without modification. The method also permits sampling in vivo permitting real-time ambient studies of microbial communities.

Cyclopropenimine superbases: Competitive initiation processes in lactide polymerization

DOE PAGES

Stukenbroeker, Tyler S.; Bandar, Jeffrey S.; Zhang, Xiangyi; ...

2015-07-30

Cyclopropenimine superbases were employed in this study to catalyze the ring-opening polymerization of lactide. Polymerization occurred readily in the presence and absence of alcohol initiators. Polymerizations in the absence of alcohol initiators revealed a competitive initiation mechanism involving deprotonation of lactide by the cyclopropenimine to generate an enolate. NMR and MALDI-TOF analysis of the poly(lactides) generated from cyclopropenimines in the absence of alcohol initiators showed acylated lactide and hydroxyl end groups. Finally, model studies and comparative experiments with guanidine and phosphazene catalysts revealed the subtle influence of the nature of the superbase on competitive initiation processes.

Gaining efficiency by centralising the corporate business resiliency process.

PubMed

Martinez, Robert

2017-06-01

Organisations have compiled many business continuity plans over the years in response to uncontrollable events and natural disasters. As the types of threats increase, even more plans are being created. Unfortunately, many corporations do not communicate the existence of these various plans outside of their centre of excellence. Creating a centralised oversight of your business resiliency process brings many benefits, including greater awareness, a bigger pool of expertise, common terminology and reducing the chances of redundant efforts. Having an overarching corporate response plan in place makes it possible to have high-level leadership trained and ready in case an extreme event occurs.

Tourmaline as a recorder of ore-forming processes

USGS Publications Warehouse

Slack, John F.; Trumbull, Robert B.

2011-01-01

Tourmaline occurs in diverse types of hydrothermal mineral deposits and can be used to constrain the nature and evolution of ore-forming fl uids. Because of its broad range in composition and retention of chemical and isotopic signatures, tourmaline may be the only robust recorder of original mineralizing processes in some deposits. Microtextures and in situ analysis of compositional and isotopic variations in ore-related tourmaline provide valuable insights into hydrothermal systems in seafl oor, sedimentary, magmatic, and metamorphic environments. Deciphering the hydrothermal record in tourmaline also holds promise for aiding exploration programs in the search for new ore deposits.

Accommodating Grief on Twitter: An Analysis of Expressions of Grief Among Gang Involved Youth on Twitter Using Qualitative Analysis and Natural Language Processing.

PubMed

Patton, Desmond Upton; MacBeth, Jamie; Schoenebeck, Sarita; Shear, Katherine; McKeown, Kathleen

2018-01-01

There is a dearth of research investigating youths' experience of grief and mourning after the death of close friends or family. Even less research has explored the question of how youth use social media sites to engage in the grieving process. This study employs qualitative analysis and natural language processing to examine tweets that follow 2 deaths. First, we conducted a close textual read on a sample of tweets by Gakirah Barnes, a gang-involved teenaged girl in Chicago, and members of her Twitter network, over a 19-day period in 2014 during which 2 significant deaths occurred: that of Raason "Lil B" Shaw and Gakirah's own death. We leverage the grief literature to understand the way Gakirah and her peers express thoughts, feelings, and behaviors at the time of these deaths. We also present and explain the rich and complex style of online communication among gang-involved youth, one that has been overlooked in prior research. Next, we overview the natural language processing output for expressions of loss and grief in our data set based on qualitative findings and present an error analysis on its output for grief. We conclude with a call for interdisciplinary research that analyzes online and offline behaviors to help understand physical and emotional violence and other problematic behaviors prevalent among marginalized communities.

Accommodating Grief on Twitter: An Analysis of Expressions of Grief Among Gang Involved Youth on Twitter Using Qualitative Analysis and Natural Language Processing

PubMed Central

Patton, Desmond Upton; MacBeth, Jamie; Schoenebeck, Sarita; Shear, Katherine; McKeown, Kathleen

2018-01-01

There is a dearth of research investigating youths’ experience of grief and mourning after the death of close friends or family. Even less research has explored the question of how youth use social media sites to engage in the grieving process. This study employs qualitative analysis and natural language processing to examine tweets that follow 2 deaths. First, we conducted a close textual read on a sample of tweets by Gakirah Barnes, a gang-involved teenaged girl in Chicago, and members of her Twitter network, over a 19-day period in 2014 during which 2 significant deaths occurred: that of Raason “Lil B” Shaw and Gakirah’s own death. We leverage the grief literature to understand the way Gakirah and her peers express thoughts, feelings, and behaviors at the time of these deaths. We also present and explain the rich and complex style of online communication among gang-involved youth, one that has been overlooked in prior research. Next, we overview the natural language processing output for expressions of loss and grief in our data set based on qualitative findings and present an error analysis on its output for grief. We conclude with a call for interdisciplinary research that analyzes online and offline behaviors to help understand physical and emotional violence and other problematic behaviors prevalent among marginalized communities. PMID:29636619

The economic value of pelargonic acid as a natural herbicide in sweet bell peppers

USDA-ARS?s Scientific Manuscript database

Economic return on investment in respect to weed control management practices continue to be an essential element in use of naturally occurring substances for weed control in vegetable production. Pelargonic acid, although not certified as organic, is naturally occurring in many plants, animals, and...

The Frequency, Nature, and Effects of Naturally Occurring Appearance-Focused Social Comparisons

ERIC Educational Resources Information Center

Leahey, Tricia M.; Crowther, Janis H.; Mickelson, Kristin D.

2007-01-01

This research examined the effects of naturally occurring appearance-focused social comparisons on women's affect, body satisfaction, and weight-related cognitions. During their daily activities, women reporting body dissatisfaction (n = 53) and women reporting body satisfaction (n = 34) recorded their reactions to comparison information.…

7 CFR 1945.20 - Making EM loans available.

Code of Federal Regulations, 2012 CFR

2012-01-01

... emergency declaration by the President; or under a natural disaster determination by the Secretary of... subpart) that such losses have occurred as a result of a natural disaster. Any determination made by the... that a natural disaster has occurred, the Secretary will acknowledge the request in writing and...

Arsenic and mercury contamination related to historical goldmining in the Sierra Nevada, California

USGS Publications Warehouse

Alpers, Charles N.

2017-01-01

Arsenic (As) is a naturally occurring constituent in low-sulphide gold-quartz vein deposits, the dominant deposit type for lode mines in the Sierra Nevada Foothills (SNFH) gold (Au) province of California. Concentrations of naturally occurring mercury (Hg) in the SNFH Au province are low, but extensive use and loss of elemental Hg during amalgamation processing of ore from lode and placer Au deposits led to widespread contamination of Hg in the Sierra Nevada foothills and downstream areas, such as the Sacramento–San Joaquin Delta and San Francisco Bay. This review paper provides an overview of As and Hg contamination related to historical Au mining in the Sierra Nevada of California. It summarizes the geology, mineralogy, and geochemistry of the Au deposits, and provides information on specific areas where detailed studies have been done in association with past, ongoing, and planned remediation activities related to the environmental As and Hg contamination.Arsenic is a naturally occurring constituent in low-sulphide Au-quartz vein deposits, the dominant deposit type for lode mines in the Sierra Nevada Foothills (SNFH) Au province (Ashley 2002). Because of elevated concentrations of As in accessory iron-sulphide minerals including arsenopyrite (FeAsS) and arsenian pyrite (Fe(S,As)2), As is commonly a contaminant of concern in lode Au mine waste, including waste rock and mill tailings. The principal pathways of human As exposure from mine waste include ingestion of soil or drinking water, and inhalation of dust in contaminated areas (Mitchell 2014).Concentrations of naturally occurring Hg in the SNFH Au province are low, but extensive use and loss of elemental Hg during amalgamation processing of ore from lode and placer Au deposits (Churchill 2000) led to widespread contamination of Hg in the Sierra Nevada foothills and downstream areas, such as the Sacramento–San Joaquin Delta and San Francisco Bay (Alpers et al. 2005a). Conversion of Hg to monomethylmercury (MeHg) by sulphate-reducing and iron-reducing microbes facilitates its bioaccumulation (Wiener et al. 2003). The human Hg exposure pathway of main concern is ingestion of MeHg from sport (non-commercial) fish, especially higher trophic levels such as bass species (Davis et al. 2008). Wildlife exposure to MeHg is also a concern because of chronic and reproductive effects, for example in fish-eating and invertebrate-foraging birds (e.g. Wiener et al. 2003; Eagles-Smith et al. 2009; Ackerman et al. 2016).

Life-cycle analysis of shale gas and natural gas.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, C.E.; Han, J.; Burnham, A.

2012-01-27

The technologies and practices that have enabled the recent boom in shale gas production have also brought attention to the environmental impacts of its use. Using the current state of knowledge of the recovery, processing, and distribution of shale gas and conventional natural gas, we have estimated up-to-date, life-cycle greenhouse gas emissions. In addition, we have developed distribution functions for key parameters in each pathway to examine uncertainty and identify data gaps - such as methane emissions from shale gas well completions and conventional natural gas liquid unloadings - that need to be addressed further. Our base case results showmore » that shale gas life-cycle emissions are 6% lower than those of conventional natural gas. However, the range in values for shale and conventional gas overlap, so there is a statistical uncertainty regarding whether shale gas emissions are indeed lower than conventional gas emissions. This life-cycle analysis provides insight into the critical stages in the natural gas industry where emissions occur and where opportunities exist to reduce the greenhouse gas footprint of natural gas.« less

Interaction Between Syntactic Structure and Information Structure in the Processing of a Head-Final Language.

PubMed

Koizumi, Masatoshi; Imamura, Satoshi

2017-02-01

The effects of syntactic and information structures on sentence processing load were investigated using two reading comprehension experiments in Japanese, a head-final SOV language. In the first experiment, we discovered the main effects of syntactic and information structures, as well as their interaction, showing that interaction of these two factors is not restricted to head-initial languages. The second experiment revealed that the interaction between syntactic structure and information structure occurs at the second NP (O of SOV and S of OSV), which, crucially, is a pre-head position, suggesting the incremental nature of the processing of both syntactic structure and information structure in head-final languages.

Triggered lightning strikes to aircraft and natural intracloud discharges

NASA Technical Reports Server (NTRS)

Mazur, Vladislav

1989-01-01

The physical model of Mazur (1989) for triggering lightning strikes by aircraft was used to interpret the initiation of intracloud flashes observed by the French UHF-VHF interferometric system. It is shown that both the intracloud discharges and airplane-triggered lightning strikes were initiated by simultaneous bidirectional development of the negative stepped leader and the positive leader-continous current process. However, the negative stepped leader phase in triggered flashes is of shorter duration (tens of milliseconds), than that in intracloud flashes (usually hundreds of milliseconds). This is considered to be due to the fact that, on the aircraft there is a single initiation process, versus the numerous initiation processes that occur inside the cloud.

Contaminant Attenuation and Transport Characterization of 200-UP-1 Operable Unit Sediment Samples

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Brady D.; Szecsody, James E.; Qafoku, Nikolla

Contaminants disposed of at the land surface migrate through the vadose zone, forming plumes in groundwater. Processes that occur in the groundwater can attenuate contaminant concentrations during transport through the aquifer. For this reason, quantifying contaminant attenuation and contaminant transport processes in the aquifer, in support of the conceptual site model (CSM) and fate and transport modeling, are important for assessing the need for, and type of, remediation in the groundwater, including monitored natural attenuation (MNA). The framework to characterize attenuation and transport processes provided in U.S. Environmental Protection Agency (EPA) guidance documents was used to guide the laboratory effortmore » reported herein.« less

Statistical Evolution of the Lightning Flash

NASA Astrophysics Data System (ADS)

Zoghzoghy, F. G.; Cohen, M.; Said, R.; Inan, U. S.

2012-12-01

Natural lightning is one of the most fascinating and powerful electrical processes on Earth. To date, the physics behind this natural phenomenon are not fully understood, due primarily to the difficulty of obtaining measurements inside thunderstorms and to the wide range of timescales involved (from nanoseconds to seconds). Our aim is to use accurate lightning geo-location data from the National Lightning Detection Network (NLDN) to study statistical patterns in lightning, taking advantage of the fact that millions of lightning flashes occur around the globe every day. We present two sets of results, one involving the patterns of flashes in a storm, and a second involving the patterns of strokes in a flash. These patterns can provide a surrogate measure of the timescales and the spatial extents of the underlying physical processes. First, we study the timescales of charge buildup inside thunderstorms. We find that, following a lightning flash, the probability of another neighboring flash decreases and takes tens of seconds to recover. We find that this suppression effect is a function of flash type, stroke peak current, cloud-to-ground (CG) stroke multiplicity, and other lightning and geographical parameters. We find that the probabilities of subsequent flashes are more suppressed following oceanic lightning, or following flashes with higher peak currents and/or higher multiplicities (for CG flashes). Second, we use NLDN data to study the evolution of the strokes within a CG flash. A CG flash typically includes multiple return strokes, which can occur in the same channel or in multiple channels within a few kilometers. We cluster NLDN stroke data into flashes and produce the probability density function of subsequent strokes as a function of distance and time-delays relative to the previous stroke. Using this technique, we investigate processes which occur during the CG lightning flash with nanosecond to millisecond timescales. For instance, our results suggest that subsequent strokes that occur in a newly formed channel follow a pattern that propagates at a speed of ~200 km/s. We present our statistical techniques and discuss more thoroughly our work and results.

In situ observations of bubble growth in basaltic, andesitic and rhyodacitic melts

NASA Astrophysics Data System (ADS)

Masotta, M.; Ni, H.; Keppler, H.

2014-02-01

Bubble growth strongly affects the physical properties of degassing magmas and their eruption dynamics. Natural samples and products from quench experiments provide only a snapshot of the final state of volatile exsolution, leaving the processes occurring during its early stages unconstrained. In order to fill this gap, we present in situ high-temperature observations of bubble growth in magmas of different compositions (basalt, andesite and rhyodacite) at 1,100 to 1,240 °C and 0.1 MPa (1 bar), obtained using a moissanite cell apparatus. The data show that nucleation occurs at very small degrees of supersaturaturation (<60 MPa in basalt and andesite, 200 MPa in rhyodacite), probably due to heterogeneous nucleation of bubbles occurring simultaneously with the nucleation of crystals. During the early stages of exsolution, melt degassing is the driving mechanism of bubble growth, with coalescence becoming increasingly important as exsolution progresses. Ostwald ripening occurs only at the end of the process and only in basaltic melt. The average bubble growth rate ( G R) ranges from 3.4 × 10-6 to 5.2 × 10-7 mm/s, with basalt and andesite showing faster growth rates than rhyodacite. The bubble number density ( N B) at nucleation ranges from 7.9 × 104 mm-3 to 1.8 × 105 mm-3 and decreases exponentially over time. While the rhyodacite melt maintained a well-sorted bubble size distribution (BSD) through time, the BSDs of basalt and andesite are much more inhomogeneous. Our experimental observations demonstrate that bubble growth cannot be ascribed to a single mechanism but is rather a combination of many processes, which depend on the physical properties of the melt. Depending on coalescence rate, annealing of bubbles following a single nucleation event can produce complex bubble size distributions. In natural samples, such BSDs may be misinterpreted as resulting from several separate nucleation events. Incipient crystallization upon cooling of a magma may allow bubble nucleation already at very small degrees of supersaturation and could therefore be an important trigger for volatile release and explosive eruptions.

Natural and Unnatural Oil Layers on the Surface of the Gulf of Mexico Detected and Quantified in Synthetic Aperture RADAR Images with Texture Classifying Neural Network Algorithms

NASA Astrophysics Data System (ADS)

MacDonald, I. R.; Garcia-Pineda, O. G.; Morey, S. L.; Huffer, F.

2011-12-01

Effervescent hydrocarbons rise naturally from hydrocarbon seeps in the Gulf of Mexico and reach the ocean surface. This oil forms thin (~0.1 μm) layers that enhance specular reflectivity and have been widely used to quantify the abundance and distribution of natural seeps using synthetic aperture radar (SAR). An analogous process occurred at a vastly greater scale for oil and gas discharged from BP's Macondo well blowout. SAR data allow direct comparison of the areas of the ocean surface covered by oil from natural sources and the discharge. We used a texture classifying neural network algorithm to quantify the areas of naturally occurring oil-covered water in 176 SAR image collections from the Gulf of Mexico obtained between May 1997 and November 2007, prior to the blowout. Separately we also analyzed 36 SAR images collections obtained between 26 April and 30 July, 2010 while the discharged oil was visible in the Gulf of Mexico. For the naturally occurring oil, we removed pollution events and transient oceanographic effects by including only the reflectance anomalies that that recurred in the same locality over multiple images. We measured the area of oil layers in a grid of 10x10 km cells covering the entire Gulf of Mexico. Floating oil layers were observed in only a fraction of the total Gulf area amounting to 1.22x10^5 km^2. In a bootstrap sample of 2000 replications, the combined average area of these layers was 7.80x10^2 km^2 (sd 86.03). For a regional comparison, we divided the Gulf of Mexico into four quadrates along 90° W longitude, and 25° N latitude. The NE quadrate, where the BP discharge occurred, received on average 7.0% of the total natural seepage in the Gulf of Mexico (5.24 x10^2 km^2, sd 21.99); the NW quadrate received on average 68.0% of this total (5.30 x10^2 km^2, sd 69.67). The BP blowout occurred in the NE quadrate of the Gulf of Mexico; discharged oil that reached the surface drifted over a large area north of 25° N. Performing a similar estimate using 5x5 km grid cells, we observed discharged oil over an area of 1.20x10^5 km^2; 91% of this area was east of 90° W. The average area oil covered water observed in the SAR images was 4.41x104^ km^2, 98% of which was observed in the eastern Gulf. Numerical oil spill model experiments are used to clarify the distinction between the area impacted by the BP oil spill and the surface slicks due to known natural seeps. Natural oil seepage has been cited as a background source of hydrocarbon contamination in the Gulf of Mexico. Our direct comparison shows that during the blowout, the discharged oil impacted an average area two orders of magnitude greater than the entire Gulf total and three orders of magnitude greater than the usual dose received in the northeastern region. Because the layers of discharged oil were often many times thicker than natural seep oil, additional scale factors are required to show the true difference in doses. These differences should be weighed when evaluating the relative impact of natural and unnatural oil in a large marine ecosystem.

Prostate Cancer Prevention

MedlinePlus

... that occurs naturally in some foods, such as green vegetables, beans and orange juice. Folic acid is ... that occurs naturally in some foods, such as green vegetables, beans and orange juice. Folic acid is ...

Moonquakes and lunar tectonism results from the Apollo passive seismic experiment.

NASA Technical Reports Server (NTRS)

Latham, G.; Ewing, M.; Dorman, J.; Lammlein, D.; Press, F.; Toksoz, N.; Sutton, G.; Duennebier, F.; Nakamura, Y.

1972-01-01

The natural seismicity of the moon appears to be very low relative to that of the earth. However, moonquakes do occur. They are detected by the stations of the Apollo seismic network at an average rate of 1800/yr at Station 14 and at lower rates at Stations 12 and 15. All of the moonquakes are small, and in the few cases for which the foci have been located, they occur at great depth (about 800 km). The frequency of occurrence of moonquakes is strongly correlated with lunar tides. The dynamic processes that generate quakes are clearly much less vigorous within the moon than they are within the earth.

A two-stage model of fracture of rocks

USGS Publications Warehouse

Kuksenko, V.; Tomilin, N.; Damaskinskaya, E.; Lockner, D.

1996-01-01

In this paper we propose a two-stage model of rock fracture. In the first stage, cracks or local regions of failure are uncorrelated occur randomly throughout the rock in response to loading of pre-existing flaws. As damage accumulates in the rock, there is a gradual increase in the probability that large clusters of closely spaced cracks or local failure sites will develop. Based on statistical arguments, a critical density of damage will occur where clusters of flaws become large enough to lead to larger-scale failure of the rock (stage two). While crack interaction and cooperative failure is expected to occur within clusters of closely spaced cracks, the initial development of clusters is predicted based on the random variation in pre-existing Saw populations. Thus the onset of the unstable second stage in the model can be computed from the generation of random, uncorrelated damage. The proposed model incorporates notions of the kinetic (and therefore time-dependent) nature of the strength of solids as well as the discrete hierarchic structure of rocks and the flaw populations that lead to damage accumulation. The advantage offered by this model is that its salient features are valid for fracture processes occurring over a wide range of scales including earthquake processes. A notion of the rank of fracture (fracture size) is introduced, and criteria are presented for both fracture nucleation and the transition of the failure process from one scale to another.

Modeling Child–Nature Interaction in a Nature Preschool: A Proof of Concept

PubMed Central

Kahn, Peter H.; Weiss, Thea; Harrington, Kit

2018-01-01

This article provides a proof of concept for an approach to modeling child–nature interaction based on the idea of interaction patterns: characterizations of essential features of interaction between humans and nature, specified abstractly enough such that countless different instantiations of each one can occur – in more domestic or wild forms – given different types of nature, people, and purposes. The model draws from constructivist psychology, ecological psychology, and evolutionary psychology, and is grounded in observational data collected through a time-sampling methodology at a nature preschool. Through using a nature language that emphasizes ontogenetic and phylogenetic significance, seven keystone interaction patterns are described for this nature preschool: using one’s body vigorously in nature, striking wood on wood, constructing shelter, being in solitude in nature, lying on earth, cohabiting with a wild animal, and being outside in weather. These 7 interactions patterns are then brought together with 13 other patterns published elsewhere to provide a total of 20 keystone interaction patterns that begin to fill out the model, and to show its promise. Discussion focuses on what the model aims to be in terms of both product and process, on what work the model can currently do, and how to further develop the model. PMID:29896143

Anaerobic Methane Oxidation Driven by Microbial Reduction of Natural Organic Matter in a Tropical Wetland

PubMed Central

Valenzuela, Edgardo I.; Prieto-Davó, Alejandra; López-Lozano, Nguyen E.; Hernández-Eligio, Alberto; Vega-Alvarado, Leticia; Juárez, Katy; García-González, Ana Sarahí; López, Mercedes G.

2017-01-01

ABSTRACT Wetlands constitute the main natural source of methane on Earth due to their high content of natural organic matter (NOM), but key drivers, such as electron acceptors, supporting methanotrophic activities in these habitats are poorly understood. We performed anoxic incubations using freshly collected sediment, along with water samples harvested from a tropical wetland, amended with 13C-methane (0.67 atm) to test the capacity of its microbial community to perform anaerobic oxidation of methane (AOM) linked to the reduction of the humic fraction of its NOM. Collected evidence demonstrates that electron-accepting functional groups (e.g., quinones) present in NOM fueled AOM by serving as a terminal electron acceptor. Indeed, while sulfate reduction was the predominant process, accounting for up to 42.5% of the AOM activities, the microbial reduction of NOM concomitantly occurred. Furthermore, enrichment of wetland sediment with external NOM provided a complementary electron-accepting capacity, of which reduction accounted for ∼100 nmol 13CH4 oxidized · cm−3 · day−1. Spectroscopic evidence showed that quinone moieties were heterogeneously distributed in the wetland sediment, and their reduction occurred during the course of AOM. Moreover, an enrichment derived from wetland sediments performing AOM linked to NOM reduction stoichiometrically oxidized methane coupled to the reduction of the humic analogue anthraquinone-2,6-disulfonate. Microbial populations potentially involved in AOM coupled to microbial reduction of NOM were dominated by divergent biota from putative AOM-associated archaea. We estimate that this microbial process potentially contributes to the suppression of up to 114 teragrams (Tg) of CH4 · year−1 in coastal wetlands and more than 1,300 Tg · year−1, considering the global wetland area. IMPORTANCE The identification of key processes governing methane emissions from natural systems is of major importance considering the global warming effects triggered by this greenhouse gas. Anaerobic oxidation of methane (AOM) coupled to the microbial reduction of distinct electron acceptors plays a pivotal role in mitigating methane emissions from ecosystems. Given their high organic content, wetlands constitute the largest natural source of atmospheric methane. Nevertheless, processes controlling methane emissions in these environments are poorly understood. Here, we provide tracer analysis with 13CH4 and spectroscopic evidence revealing that AOM linked to the microbial reduction of redox functional groups in natural organic matter (NOM) prevails in a tropical wetland. We suggest that microbial reduction of NOM may largely contribute to the suppression of methane emissions from tropical wetlands. This is a novel avenue within the carbon cycle in which slowly decaying NOM (e.g., humic fraction) in organotrophic environments fuels AOM by serving as a terminal electron acceptor. PMID:28341676

Anaerobic Methane Oxidation Driven by Microbial Reduction of Natural Organic Matter in a Tropical Wetland.

PubMed

Valenzuela, Edgardo I; Prieto-Davó, Alejandra; López-Lozano, Nguyen E; Hernández-Eligio, Alberto; Vega-Alvarado, Leticia; Juárez, Katy; García-González, Ana Sarahí; López, Mercedes G; Cervantes, Francisco J

2017-06-01

Wetlands constitute the main natural source of methane on Earth due to their high content of natural organic matter (NOM), but key drivers, such as electron acceptors, supporting methanotrophic activities in these habitats are poorly understood. We performed anoxic incubations using freshly collected sediment, along with water samples harvested from a tropical wetland, amended with 13 C-methane (0.67 atm) to test the capacity of its microbial community to perform anaerobic oxidation of methane (AOM) linked to the reduction of the humic fraction of its NOM. Collected evidence demonstrates that electron-accepting functional groups (e.g., quinones) present in NOM fueled AOM by serving as a terminal electron acceptor. Indeed, while sulfate reduction was the predominant process, accounting for up to 42.5% of the AOM activities, the microbial reduction of NOM concomitantly occurred. Furthermore, enrichment of wetland sediment with external NOM provided a complementary electron-accepting capacity, of which reduction accounted for ∼100 nmol 13 CH 4 oxidized · cm -3 · day -1 Spectroscopic evidence showed that quinone moieties were heterogeneously distributed in the wetland sediment, and their reduction occurred during the course of AOM. Moreover, an enrichment derived from wetland sediments performing AOM linked to NOM reduction stoichiometrically oxidized methane coupled to the reduction of the humic analogue anthraquinone-2,6-disulfonate. Microbial populations potentially involved in AOM coupled to microbial reduction of NOM were dominated by divergent biota from putative AOM-associated archaea. We estimate that this microbial process potentially contributes to the suppression of up to 114 teragrams (Tg) of CH 4 · year -1 in coastal wetlands and more than 1,300 Tg · year -1 , considering the global wetland area. IMPORTANCE The identification of key processes governing methane emissions from natural systems is of major importance considering the global warming effects triggered by this greenhouse gas. Anaerobic oxidation of methane (AOM) coupled to the microbial reduction of distinct electron acceptors plays a pivotal role in mitigating methane emissions from ecosystems. Given their high organic content, wetlands constitute the largest natural source of atmospheric methane. Nevertheless, processes controlling methane emissions in these environments are poorly understood. Here, we provide tracer analysis with 13 CH 4 and spectroscopic evidence revealing that AOM linked to the microbial reduction of redox functional groups in natural organic matter (NOM) prevails in a tropical wetland. We suggest that microbial reduction of NOM may largely contribute to the suppression of methane emissions from tropical wetlands. This is a novel avenue within the carbon cycle in which slowly decaying NOM (e.g., humic fraction) in organotrophic environments fuels AOM by serving as a terminal electron acceptor. Copyright © 2017 American Society for Microbiology.

Monitored Natural Attenuation of ino9rganic Contaminants Treatability Study Final Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crapse, K

2004-05-19

The identification and quantification of key natural attenuation processes for inorganic contaminants at D-Area is detailed herein. Two overarching goals of this evaluation of monitored natural attenuation (MNA) as a remediation strategy were (1) to better define the availability of inorganic contaminants as potential sources for transport to groundwater and uptake by environmental receptors and (2) to understand the site-specific mechanisms controlling attenuation of these inorganic contaminants through tandem geochemical and biological characterization. Data collected in this study provides input for more appropriate site groundwater transport models. Significant natural attenuation is occurring at D-Area as evidenced by relatively low aqueousmore » concentrations of constituents of concern (COCs) (Be, Ni, U, and As) at all locations characterized and the decrease in groundwater concentrations with increasing distance from the source. The observed magnitude of decrease in groundwater concentrations of COCs with distance from the D-Area Coal Pile Runoff Basin (DCPRB) could not be accounted for by the modeled physical attenuation processes of dilution/dispersion. This additional attenuation, i.e., the observed difference between the groundwater concentrations of COCs and the modeled physical attenuation, is due to biogeochemical processes occurring at the D-Area. In tandem geochemical and microbiological characterization studies designed to evaluate the mechanisms contributing to natural attenuation, pH was the single parameter found to be most predictive of contaminant attenuation. The increasing pH with distance from the source is likely responsible for increased sorption of COCs to soil surfaces within the aquifer at D-Area. Importantly, because the sediments appear to have a high buffering capacity, the acid emanating from the DCPRB has been neutralized by the soil, and these conditions have led to large Kd values at the site. Two major types of soils are present at D-Area and were evaluated in this study: upland subsurface soils associated with a low pH/high sulfate/metals plume down-gradient of the D-Area Coal Pile Runoff Basin (DCPRB) and surface ash material discharged to the wetland from the D-Area Ash Basin (488-D). Sequential extraction studies were carried out to better define the availability of inorganic contaminant sources at D-Area.« less

Phosphate analysis of natural sausage casings preserved in brines with phosphate additives as inactivating agent - Method validation.

PubMed

Wijnker, J J; Tjeerdsma-van Bokhoven, J L M; Veldhuizen, E J A

2009-01-01

Certain phosphates have been identified as suitable additives for the improvement of the microbial and mechanical properties of processed natural sausage casings. When mixed with NaCl (sodium chloride) and used under specific treatment and storage conditions, these phosphates are found to prevent the spread of foot-and-mouth disease and classical swine fever via treated casings. The commercially available Quantichrom™ phosphate assay kit has been evaluated as to whether it can serve as a reliable and low-tech method for routine analysis of casings treated with phosphate. The outcome of this study indicates that this particular assay kit has sufficient sensitivity to qualitatively determine the presence of phosphate in treated casings without interference of naturally occurring phosphate in salt used for brines in which casings are preserved.

Natural abundances of carbon isotopes in acetate from a coastal marine sediment

NASA Technical Reports Server (NTRS)

Blair, N. E.; Martens, C. S.; Des Marais, D. J.

1987-01-01

Measurements of the natural abundances of carbon isotopes were made in acetate samples isolated from the anoxic marine sediment of Cape Lookout Bight, North Carolina. The typical value of the total acetate carbon isotope ratio (delta 13C) was -16.1 +/- 0.2 per mil. The methyl and carboxyl groups were determined to be -26.4 +/- 0.3 and -6.0 +/- 0.3 per mil, respectively, for one sample. The isotopic composition of the acetate is thought to have resulted from isotopic discriminations that occurred during the cycling of that molecule. Measurements of this type, which have not been made previously in the natural environment, may provide information about the dominant microbial pathways in anoxic sediments as well as the processes that influence the carbon isotopic composition of biogenic methane from many sources.

Impact of natural (waves and currents) and anthropogenic (trawl) resuspension on the export of particulate matter to the open ocean: Application to the Gulf of Lion (NW Mediterranean)

NASA Astrophysics Data System (ADS)

Ferré, B.; Durrieu de Madron, X.; Estournel, C.; Ulses, C.; Le Corre, G.

2008-08-01

Modern sediment deposits on continental margins form a vast reservoir of particulate matter that is regularly affected by resuspension processes. Resuspension by bottom trawling on shelves with strong fishing activity can modify the scale of natural disturbance by waves and currents. Recent field data show that the impact of bottom trawls on fine sediment resuspension per unit surface is comparable with that of the largest storms. We assessed the impact of both natural and anthropogenic processes on the dispersal of riverborne particles and shelf sediments on the Gulf of Lion shelf. We performed realistic numerical simulations of resuspension and transport forced by currents and waves or by a fleet of bottom trawlers. Simulations were conducted for a 16-month period (January 1998-April 1999) to characterise the seasonal variability. The sediment dynamics takes into account bed armoring, ripple geometry and the cohesive and non-cohesive characteristics of the sediments. Essential but uncertain parameters (clay content, erosion fluxes and critical shear stress for cohesive sediment) were set with existing data. Resuspension by waves and currents was controlled by shear stress, whereas resuspension by trawls was controlled by density and distribution of the bottom trawler fleet. Natural resuspension by waves and currents mostly occurred during short seasonal episodes, and was concentrated on the inner shelf. Trawling-induced resuspension, in contrast, occurred regularly throughout the year and was concentrated on the outer shelf. The total annual erosion by trawls (5.6×10 6 t y -1, t for metric tonnes) was four orders of magnitude lower than the erosion induced by waves and currents (35.3×10 9 t y -1). However the net resuspension (erosion/deposition budget) for trawling (0.4×10 6 t y -1) was only one order of magnitude lower than that for waves and currents (9.2×10 6 t y -1). Off-shelf export concerned the finest fraction of the sediment (clays and fine silts) and took place primarily at the southwestern end of the Gulf. Off-shelf transport was favoured during the winter 1999 by a very intense episode of dense shelf water cascading. Export of sediment resuspended by trawls (0.4×10 6 t y -1) was one order of magnitude lower than export associated with natural resuspension (8.5×10 6 t y -1). Trawling-induced resuspension is thought to represent one-third of the total export of suspended sediment from the shelf. A simulation combining both resuspension processes reveals no significant changes in resuspension and export rates compared with the sum of each individual process, suggesting the absence of interference between both processes.

Development and Application of Future Climate Scenarios for Natural Resource Management in Southwestern Colorado

NASA Astrophysics Data System (ADS)

Rangwala, I.; Rondeau, R.; Wyborn, C.; Clifford, K. R.; Travis, W.

2015-12-01

Locally relevant projections of climate change provide critical insights for natural resource managers seeking to adapt their management activities to climate change in the context of uncertainty. To provide such information, we developed climate scenarios, in form of narratives and quantitative information, of future climate change and its impacts in southwestern Colorado. This information was intended to provide detailed insights into the range of changes that natural resource managers may face in the future. The scenarios were developed in an iterative process through interactions among the ecologists, social and climate scientists. In our scenario development process, climate uncertainty is acknowledged by having multiple scenarios, where each scenario is regarded as a storyline with equal likelihood as another scenario. We quantified changes in several decision relevant climate and ecological responses based on our best available understanding and provided a tight storyline for each scenario to facilitate (a) a more augmented use of scientific information in a decision-making process, (b) differential responses from stakeholders across the different scenarios, and (c) identification of strategies that could work across these multiple scenarios. Here, we discuss the process of selecting the scenarios, quantifying climate and ecological responses, and the criteria for building the narrative for each scenario. We also discuss the process by which these scenarios get used, and provide an assessment of their effectiveness and users' feedbacks that could inform the future development of these tools and processes. This research involvement and collaboration occurred, in part, as a result of the PACE Fellowship Program that is associated with NOAA Climate Program Office and the U.S. CLIVAR community.

Field Investigation of Natural Attenuation of a Petroleum Hydrocarbon Contaminated Aquifer, Gyeonggi Province, Korea

NASA Astrophysics Data System (ADS)

Yang, J.; Lee, K.; Bae, G.

2004-12-01

In remediation of a petroleum hydrocarbon contaminated aquifer, natural attenuation may be significant as a remedial alternative. Therefore, natural attenuation should be investigated in the field in order to effectively design and evaluate the remediation strategy at the contaminated site. This study focused on evaluating the natural attenuation for benzene, toluene, ethylbenzene, and xylene (BTEX) at a contaminated site in South Korea. At the study site, the aquifer is composed of a high permeable gravel layer and relatively low permeable sandy-silt layers. Groundwater level vertically fluctuated between 1m and 2m throughout the year (April, 2003~June, 2004) and showed direct response to rainfall events. Chemical analyses of sampled groundwater were performed to investigate the concentrations of various chemical species which are associated with the natural attenuation processes. To evaluate the degree of the biodegradation, the expressed biodegradation capacity (EBC) analysis was done using aerobic respiration, nitrate reduction, manganese reduction, ferric iron reduction, and sulfate reduction as an indicator. High EBC value of sulfate indicate that anaerobic biodegradation by sulfate reduction was a dominant process of mineralization of BTEX at this site. The EBC values decrease sensitively when heavy rainfall occurs due to the dilution and inflow of electron acceptors through a gravel layer. The first-order biodegradation rates of BTEX were estimated by means of the Buscheck and Alcantar method (1995). Results show that the natural attenuation rate of benzene was the highest among the BTEX.

AcuteToxicological Responses of Fischer Rats to Naturally Occurring Asbestos Samples from the United States and Canada

EPA Science Inventory

The potential public health issues related to exposure to natural asbestos deposits (commonly termed naturally occurring asbestos, NO A) has gained the regulatory and media spotlight in recent years. Arguably the most well known example is Libby, Montana, the site of the largest ...

Concentrations of the naturally occurring radionucleides Pb-210, Po-210, and Ra-226 in aquatic fauna

NASA Technical Reports Server (NTRS)

Holtzman, R. B.

1969-01-01

Study reveals naturally occurring radionuclides are ubiquitous and contribute a substantial fraction of the natural radiation dose to humans and various biota. Measurements may be useful in ecological and other biological problems such as tracing food chains of animals and study of the metabolism of these elements.

New drugs from ancient natural foods. Oleocanthal, the natural occurring spicy compound of olive oil: a brief history.

PubMed

Scotece, Morena; Conde, Javier; Abella, Vanessa; Lopez, Veronica; Pino, Jesús; Lago, Francisca; Smith, Amos B; Gómez-Reino, Juan J; Gualillo, Oreste

2015-04-01

Extra-virgin olive oil (EVOO), a principal component of the Mediterranean diet (Med diet), is one of the most ancient known foods and has long been associated with health benefits. Many phenolic compounds extracted from Olea europea L. have attracted attention since their discovery. Among these phenolic constituents, oleocanthal has recently emerged as a potential therapeutic molecule for different diseases, showing relevant pharmacological properties in various pathogenic processes, including inflammation, cancers and neurodegenerative diseases. Here, we discuss and summarize the most recent pharmacological evidence for the medical relevance of oleocanthal, focusing our attention on its anti-inflammatory and chemotherapeutic roles. Copyright © 2014 Elsevier Ltd. All rights reserved.

Decoding molecular interactions in microbial communities

PubMed Central

Abreu, Nicole A.; Taga, Michiko E.

2016-01-01

Microbial communities govern numerous fundamental processes on earth. Discovering and tracking molecular interactions among microbes is critical for understanding how single species and complex communities impact their associated host or natural environment. While recent technological developments in DNA sequencing and functional imaging have led to new and deeper levels of understanding, we are limited now by our inability to predict and interpret the intricate relationships and interspecies dependencies within these communities. In this review, we highlight the multifaceted approaches investigators have taken within their areas of research to decode interspecies molecular interactions that occur between microbes. Understanding these principles can give us greater insight into ecological interactions in natural environments and within synthetic consortia. PMID:27417261

Thermodynamic Changes in the Coal Matrix - Gas - Moisture System Under Pressure Release and Phase Transformations of Gas Hydrates

NASA Astrophysics Data System (ADS)

Dyrdin, V. V.; Smirnov, V. G.; Kim, T. L.; Manakov, A. Yu.; Fofanov, A. A.; Kartopolova, I. S.

2017-06-01

The physical processes occurring in the coal - natural gas system under the gas pressure release were studied experimentally. The possibility of gas hydrates presence in the inner space of natural coal was shown, which decomposition leads to an increase in the amount of gas passing into the free state. The decomposition of gas hydrates can be caused either by the seam temperature increase or the pressure decrease to lower than the gas hydrates equilibrium curve. The contribution of methane released during gas hydrates decomposition should be taken into account in the design of safe mining technologies for coal seams prone to gas dynamic phenomena.

Learn about Nontuberculous Mycobacteria (NTM)

MedlinePlus

... are naturally-occurring organisms found in water and soil. NTM lung infection occurs when a person inhales ... Nontuberculous mycobacteria (NTM) are organisms naturally found in soil and water. NTM infections can become chronic and ...

Biomining with bacteriophage: selectivity of displayed peptides for naturally occurring sphalerite and chalcopyrite.

PubMed

Curtis, Susan B; Hewitt, Jeff; Macgillivray, Ross T A; Dunbar, W Scott

2009-02-01

During mineral processing, concentrates of sulfide minerals of economic interest are formed by froth flotation of fine ore particles. The method works well but recovery and selectivity can be poor for ores with complex mineralogy. There is considerable interest in methods that improve the selectivity of this process while avoiding the high costs of using flotation chemicals. Here we show the first application of phage biotechnology to the processing of economically important minerals in ore slurries. A random heptapeptide library was screened for peptide sequences that bind selectively to the minerals sphalerite (ZnS) and chalcopyrite (CuFeS2). After several rounds of enrichment, cloned phage containing the surface peptide loops KPLLMGS and QPKGPKQ bound specifically to sphalerite. Phage containing the peptide loop TPTTYKV bound to both sphalerite and chalcopyrite. By using an enzyme-linked immunosorbant assay (ELISA), the phage was characterized as strong binders compared to wild-type phage. Specificity of binding was confirmed by immunochemical visualization of phage bound to mineral particles but not to silica (a waste mineral) or pyrite. The current study focused primarily on the isolation of ZnS-specific phage that could be utilized in the separation of sphalerite from silica. At mining sites where sphalerite and chalcopyrite are not found together in natural ores, the separation of sphalerite from silica would be an appropriate enrichment step. At mining sites where sphalerite and chalcopyrite do occur together, more specific phage would be required. This bacteriophage has the potential to be used in a more selective method of mineral separation and to be the basis for advanced methods of mineral processing.

Initial Assessment of the Effects of Nonmetallic Inclusions on Fatigue Life of Powder-Metallurgy-Processed Udimet(TM) 720

NASA Technical Reports Server (NTRS)

Gabb, T. P.; Telesman, J.; Kantzos, P. T.; Bonacuse, P. J.; Barrie, R. L.

2002-01-01

The fatigue lives of modern powder metallurgy (PM) disk alloys are influenced by variabilities in alloy microstructure and mechanical properties. These properties can vary due to the different steps of materials/component processing and machining. One of these variables, the presence of nonmetallic inclusions, has been shown to significantly degrade low-cycle fatigue (LCF) life. Nonmetallic inclusions are inherent defects in powder alloys that are a by-product of powder-processing techniques. Contamination of the powder can occur in the melt, during powder atomization, or during any of the various handling processes through consolidation. In modern nickel disk powder processing facilities, the levels of inclusion contamination have been reduced to less than 1 part per million by weight. Despite the efforts of manufacturers to ensure the cleanliness of their powder production processes, the presence of inclusions remains a source of great concern for the designer. the objective of this study was to investigate the effects on fatigue life of these inclusions. Since natural inclusions occur so infrequently, elevated levels of inclusions were carefully introduced in a nickel-based disk superalloy, Udimet 720 (registered trademark of Special Metals Corporation), produced using PM processing. Multiple strain-controlled fatigue tests were then performed on this material at 650 C. Analyses were performed to compare the LCF lives and failure initiation sites as functions of inclusion content and fatigue conditions. A large majority of the failures in specimens with introduced inclusions occurred at cracks initiating from inclusions at the specimen surface. The inclusions could reduce fatigue life by up to 100 times. These effects were found to be dependent on strain range and strain ratio. Tests at lower strain ranges and higher strain ratios produced larger effects of inclusions on life.

Naturally occurring hazardous materials.

DOT National Transportation Integrated Search

2011-12-01

The study of naturally occurring hazardous materials (NOHMs) was conceived as a proactive response to assure that the Oregon : Department of Transportation (ODOT) maintenance and construction activities take the presence of NOHMs into account. The la...

The Formation of Chimeric Nanomorphologies, as a Reflection of Naturally Occurring Thermodynamic Processes

NASA Astrophysics Data System (ADS)

Naziris, N.; Demetzos, C.

2017-11-01

The self-assembly process of different in nature biomaterials leads to the morphogenesis of various nano-structures, where the individual molecule properties (e.g. hydrophilic-to-hydrophobic balance and elasticity), profoundly affect the intermediate surfaces’ interfacial thermodynamics. Herein, the mixing of a phospholipid and an amphiphilic block copolymer, through the thin-film hydration method, gave different morphologies, among which there were vesicles (i.e. liposomes and polymersomes), micelles and worm-like structures. The formation of such variety of structures is attributed to divergent entropic pathways, which are determined by a number of parameters, such as the lipid:polymer molar ratio and the polymer composition. The developed nanosystems are considered as chimeric/mixed, because of the two different in type biomaterials that compose them. The vesicles also exhibited membrane “irregularities”, which are connected with their biophysical behavior. Nature has “chosen” vesicular forms to be the thermodynamically stable “biological apartments”, in which life was enclosed and additionally, vesicles provided compartmentalized systems, where the intracellular environment was built. Phospholipid properties result in membranes/bilayers that harmonically assimilate other molecules, like proteins and retain their integrity and functionality, while gaining additional features. A cause that alters this relationship might induce changes in the membrane composition and morphology, with respect to lipid rafts/domains, what has been linked with the activation and development of certain human disorders/diseases. The self-assembly of two different biomaterials into various structures that present distinct membrane phenomena is believed to simulate these natural processes.

Sulfate-reducing anaerobic ammonium oxidation as a potential treatment method for high nitrogen-content wastewater.

PubMed

Rikmann, Ergo; Zekker, Ivar; Tomingas, Martin; Tenno, Taavo; Menert, Anne; Loorits, Liis; Tenno, Toomas

2012-07-01

After sulfate-reducing ammonium oxidation (SRAO) was first assumed in 2001, several works have been published describing this process in laboratory-scale bioreactors or occurring in the nature. In this paper, the SRAO process was performed using reject water as a substrate for microorganisms and a source of NH(4) (+), with SO(4) (2-) being added as an electron acceptor. At a moderate temperature of 20°C in a moving bed biofilm reactor (MBBR) sulfate reduction along with ammonium oxidation were established. In an upflow anaerobic sludge blanket reactor (UASBR) the SRAO process took place at 36°C. Average volumetric TN removal rates of 0.03 kg-N/m³/day in the MBBR and 0.04 kg-N/m³/day in the UASBR were achieved, with long-term moderate average removal efficiencies, respectively. Uncultured bacteria clone P4 and uncultured planctomycete clone Amx-PAn30 were detected from the biofilm of the MBBR, from sludge of the UASBR uncultured Verrucomicrobiales bacterium clone De2102 and Uncultured bacterium clone ATB-KS-1929 were found also. The stoichiometrical ratio of NH(4) (+) removal was significantly higher than could be expected from the extent of SO(4) (2-) reduction. This phenomenon can primarily be attributed to complex interactions between nitrogen and sulfur compounds and organic matter present in the wastewater. The high NH(4) (+) removal ratio can be attributed to sulfur-utilizing denitrification/denitritation providing the evidence that SRAO is occurring independently and is not a result of sulfate reduction and anammox. HCO(3) (-) concentrations exceeding 1,000 mg/l were found to have an inhibiting effect on the SRAO process. Small amounts of hydrazine were naturally present in the reaction medium, indicating occurrence of the anammox process. Injections of anammox intermediates, hydrazine and hydroxylamine, had a positive effect on SRAO process performance, particularly in the case of the UASBR.

The autumn effect: timing of physical dormancy break in seeds of two winter annual species of Geraniaceae by a stepwise process

PubMed Central

Gama-Arachchige, N. S.; Baskin, J. M.; Geneve, R. L.; Baskin, C. C.

2012-01-01

Background and Aims The involvement of two steps in the physical dormancy (PY)-breaking process previously has been demonstrated in seeds of Fabaceae and Convolvulaceae. Even though there is a claim for a moisture-controlled stepwise PY-breaking in some species of Geraniaceae, no study has evaluated the role of temperature in the PY-breaking process in this family. The aim of this study was to determine whether a temperature-controlled stepwise PY-breaking process occurs in seeds of the winter annuals Geranium carolinianum and G. dissectum. Methods Seeds of G. carolinianum and G. dissectum were stored under different temperature regimes to test the effect of storage temperature on PY-break. The role of temperature and moisture regimes in regulating PY-break was investigated by treatments simulating natural conditions. Greenhouse (non-heated) experiments on seed germination and burial experiments (outdoors) were carried out to determine the PY-breaking behaviour in the natural habitat. Key Results Irrespective of moisture conditions, sensitivity to the PY-breaking step in seeds of G. carolinianum was induced at temperatures ≥20 °C, and exposure to temperatures ≤20 °C made the sensitive seeds permeable. Sensitivity of seeds increased with time. In G. dissectum, PY-break occurred at temperatures ≥20 °C in a single step under constant wet or dry conditions and in two steps under alternate wet–dry conditions if seeds were initially kept wet. Conclusions Timing of seed germination with the onset of autumn can be explained by PY-breaking processes involving (a) two temperature-dependent steps in G. carolinianum and (b) one or two moisture-dependent step(s) along with the inability to germinate under high temperatures in G. dissectum. Geraniaceae is the third of 18 families with PY in which a two-step PY-breaking process has been demonstrated. PMID:22684684

A High-Resolution Multitechniques Approach to Characterize Bio-Organo-Mineral Associations Within Rock Samples: Tracking Biological vs Abiotic Processes? Towards a Better Understanding of the Deep Carbon Cycle.

NASA Astrophysics Data System (ADS)

Pisapia, C.

2015-12-01

Among all elements, carbon plays one of the major roles for the sustainability of life on Earth. Past considerations of the carbon cycle have mainly focused on surface processes occurring at the atmosphere, oceans and shallow crustal environments. By contrast, little is known about the Deep Carbon cycle whereas both geochemical and biological processes may induce organic carbon production and/or consumption at depth. Indeed, the nowadays-recognized capability of geochemical processes such as serpentinization to generate abiotic organic compounds as well as the existence of a potentially important intraterrestrial life raises questions about the limit of biotic/abiotic carbon on Earth's deep interior and how it impacts global biogeochemical cycles. It is then mandatory to increase our knowledge on the nature and extent of carbon reservoirs along with their sources, sinks and fluxes in the subsurface. This implies to be able to finely characterize organomineral associations within crustal rocks although it might be hampered by the scarceness and heterogeneous micrometric spatial distribution of organic molecules in natural rocks. We then developed an in situ analytical strategy based on the combination of high-resolution techniques to track organic molecules at the pore level in natural rocks and to determine their biological or abiotic origin. We associated classical high-resolution techniques and synchrotron-based imaging techniques in order to characterize their nature and localization (SEM/TEM, coupled CLSM/Raman spectroscopy, Tof-SIMS) along with their 3D-distribution relatively to mineral phases (S-FTIR, S-DeepUV, XANES, Biphoton microscopy). The effectiveness of this approach to shed light on the speciation and nature of carbon in subsurface environments will be illustrated through the study of (i) subsurface ecosystems and abiotic organic carbon within ultramafic rocks of the oceanic lithosphere as putative analogs for the nature and functioning of primitive ecosystems on Earth and of (ii) ecosystems inhabiting Archean craton and potentially playing a role in punk-rock karstification processes and rocks weathering.

Can human activities alter the drowning fate of barrier islands?

NASA Astrophysics Data System (ADS)

Lorenzo-Trueba, J.; Ashton, A. D.; Jin, D.; Hoagland, P.; Kite-Powell, H.

2012-12-01

Low-lying coastal barriers face an uncertain future over the coming century and beyond as sea levels rise, with many projections suggesting end-of-century rates of sea-level rise as high or higher than 1 cm/yr. Geologically, such rates of sea-level rise have been experienced several thousand years ago and we can use our understanding of geological processes and sedimentary evidence to help unravel the dynamics of natural barriers experiencing sea-level rise. Along many modern coastal barriers, however, anthropic change, such as beach nourishment, dune construction, and emplacement of hard structures, plays a dominant role in coastline dynamics. A fundamental question to be addressed is whether human activities intended to preserve infrastructure and beach recreation may make wholesale collapse, or 'drowning,' of barrier systems more likely. Here we present a numerical modeling tool that couples natural processes and the human responses to these changes (and the subsequent of human responses on natural processes). Recent theoretical model development suggests that barriers are intrinsically morphodynamic features, responding to sea-level rise in complex ways through the interactions of marine processes and barrier overwash. Undeveloped coastal barriers would therefore respond to an accelerated sea-level rise in complex, less predictable manners than suggested by existing long-term models. We have developed a model that examines non-equilibrium cross-shore evolution of barrier systems at decadal to centennial temporal scales, focusing on the interactions between processes of shoreface evolution and overwash deposition. Model responses demonstrate two means of barrier collapse during sea-level rise: 'height drowning', which occurs when overwash fluxes are insufficient to maintain the landward migration rate required to keep in pace with sea-level rise, and 'width drowning', which occurs when the shoreface response is insufficient to maintain the barrier geometry during landward migration. The model also demonstrates the potential for discontinuous shoreline retreat, with alternating periods of barrier stability and rapid migration, even for constant rates of sea-level rise. Anthropic activities can strongly interact with these behaviors. In particular, considering only cross-shore processes, beach nourishment activities widen the beach and can affect shoreface fluxes, and dune building, which curtails the overwash process, can potentially enhance barrier drowning by reducing overwash fluxes. Furthermore, coastal protection activities of adjacent communities or even individual property holders can be uncoordinated or coordinated, with their effects coupled along the coast through coastal reorientation and gradients in alongshore sediment transport. In the coordinated framework, owners act in concert to alter the barrier based upon community benefits, whereas in the non-coordinated framework owners alter only their own property. Another important role in management is the perception of future sea-level-rise-associated losses—communities manage their coast differently depending on their adopted forecast for sea-level rise. We find that coordinated behavior coupled with natural processes can substantially affect the drowning scenarios from the individual decision-making process.

The geochemistry of naturally occurring methane and saline groundwater in an area of unconventional shale gas development

NASA Astrophysics Data System (ADS)

Harkness, Jennifer S.; Darrah, Thomas H.; Warner, Nathaniel R.; Whyte, Colin J.; Moore, Myles T.; Millot, Romain; Kloppmann, Wolfram; Jackson, Robert B.; Vengosh, Avner

2017-07-01

Since naturally occurring methane and saline groundwater are nearly ubiquitous in many sedimentary basins, delineating the effects of anthropogenic contamination sources is a major challenge for evaluating the impact of unconventional shale gas development on water quality. This study investigates the geochemical variations of groundwater and surface water before, during, and after hydraulic fracturing and in relation to various geospatial parameters in an area of shale gas development in northwestern West Virginia, United States. To our knowledge, we are the first to report a broadly integrated study of various geochemical techniques designed to distinguish natural from anthropogenic sources of natural gas and salt contaminants both before and after drilling. These measurements include inorganic geochemistry (major cations and anions), stable isotopes of select inorganic constituents including strontium (87Sr/86Sr), boron (δ11B), lithium (δ7Li), and carbon (δ13C-DIC), select hydrocarbon molecular (methane, ethane, propane, butane, and pentane) and isotopic tracers (δ13C-CH4, δ13C-C2H6), tritium (3H), and noble gas elemental and isotopic composition (helium, neon, argon) in 105 drinking-water wells, with repeat testing in 33 of the wells (total samples = 145). In a subset of wells (n = 20), we investigated the variations in water quality before and after the installation of nearby (<1 km) shale-gas wells. Methane occurred above 1 ccSTP/L in 37% of the groundwater samples and in 79% of the samples with elevated salinity (chloride > 50 mg/L). The integrated geochemical data indicate that the saline groundwater originated via naturally occurring processes, presumably from the migration of deeper methane-rich brines that have interacted extensively with coal lithologies. These observations were consistent with the lack of changes in water quality observed in drinking-water wells following the installation of nearby shale-gas wells. In contrast to groundwater samples that showed no evidence of anthropogenic contamination, the chemistry and isotope ratios of surface waters (n = 8) near known spills or leaks occurring at disposal sites mimicked the composition of Marcellus flowback fluids, and show direct evidence for impact on surface water by fluids accidentally released from nearby shale-gas well pads and oil and gas wastewater disposal sites. Overall this study presents a comprehensive geochemical framework that can be used as a template for assessing the sources of elevated hydrocarbons and salts to water resources in areas potentially impacted by oil and gas development.

Withaferin A is a leptin sensitizer with strong antidiabetic properties in mice.

PubMed

Lee, Jaemin; Liu, Junli; Feng, Xudong; Salazar Hernández, Mario Andrés; Mucka, Patrick; Ibi, Dorina; Choi, Jae Won; Ozcan, Umut

2016-09-01

The increasing global prevalence of obesity and its associated disorders points to an urgent need for the development of novel and effective therapeutic strategies that induce healthy weight loss. Obesity is characterized by hyperleptinemia and central leptin resistance. In an attempt to identify compounds that could reverse leptin resistance and thus promote weight loss, we analyzed a library of small molecules that have mRNA expression profiles similar to that of celastrol, a naturally occurring compound that we previously identified as a leptin sensitizer. Through this process, we identified another naturally occurring compound, withaferin A, that also acts as a leptin sensitizer. We found that withaferin-A treatment of mice with diet-induced obesity (DIO) resulted in a 20-25% reduction of body weight, while also decreasing obesity-associated abnormalities, including hepatic steatosis. Withaferin-A treatment marginally affected the body weight of ob/ob and db/db mice, both of which are deficient in leptin signaling. In addition, withaferin A, unlike celastrol, has beneficial effects on glucose metabolism that occur independently of its leptin-sensitizing effect. Our results show that the metabolic abnormalities of DIO can be mitigated by sensitizing animals to endogenous leptin, and they indicate that withaferin A is a potential leptin sensitizer with additional antidiabetic actions.

A possible new approach to understanding mental disorder.

PubMed

Sharples, P J

2012-09-01

The aetiology of mental disorders is not fully understood. This paper presents an analysis of the conceptual control process exploring the tools of conceptual application and the phases and the mechanism of the control process and seeks to show how the illness states of mental disorder naturally come to occur. Living occurs in a world of change. For living to occur some control is required and to exert control, to provide direction for the conceptual process, some interpretation of significance, some definition of need is also required. Such interpretation, monitoring significance in relation to the many aspects of change, forms the base on which living occurs. Change in human terms is intrinsically insecure and interpretation of significance is an interpretation of security, an interpretation of control in living. Conceptual control is a process applied to maintain security, to maintain a secure base for the interpretation of significance, it is a process applied to produce and hold a sense of control. Powering a process, producing and holding a sense of control, is an active process and so requires some form of energy. Human beings have a sense of that energy, something exhibited in terms such as full of energy, tired, exhausted. As energy is required to power the control process, accompanying the sense of energy is a sense of the ability to provide power, is a sense of the ability to hold and maintain control, is a sense of security. As available energy reduces there is difficulty holding the same sense of control, a person in the same setting comes to feel more insecure. This can result in a person experiencing mental disorder from mild to severe degree. Mild where conceptual process is applied to manage just one or a very few particular needs, severe and more general where the insecurity affects the base of interpretation. In this later case seeking to protect security can lead to mania, mood-incongruent delusions, schizophrenia. Failing ability to protect can lead to generalized anxiety disorder, mood-congruent delusions, different presentations and degrees of depression. Copyright © 2012 Elsevier Ltd. All rights reserved.

Dark States in the Light-Harvesting complex 2 Revealed by Two-dimensional Electronic Spectroscopy

PubMed Central

Ferretti, Marco; Hendrikx, Ruud; Romero, Elisabet; Southall, June; Cogdell, Richard J.; Novoderezhkin, Vladimir I.; Scholes, Gregory D.; van Grondelle, Rienk

2016-01-01

Energy transfer and trapping in the light harvesting antennae of purple photosynthetic bacteria is an ultrafast process, which occurs with a quantum efficiency close to unity. However the mechanisms behind this process have not yet been fully understood. Recently it was proposed that low-lying energy dark states, such as charge transfer states and polaron pairs, play an important role in the dynamics and directionality of energy transfer. However, it is difficult to directly detect those states because of their small transition dipole moment and overlap with the B850/B870 exciton bands. Here we present a new experimental approach, which combines the selectivity of two-dimensional electronic spectroscopy with the availability of genetically modified light harvesting complexes, to reveal the presence of those dark states in both the genetically modified and the wild-type light harvesting 2 complexes of Rhodopseudomonas palustris. We suggest that Nature has used the unavoidable charge transfer processes that occur when LH pigments are concentrated to enhance and direct the flow of energy. PMID:26857477

Correlated bursts and the role of memory range

NASA Astrophysics Data System (ADS)

Jo, Hang-Hyun; Perotti, Juan I.; Kaski, Kimmo; Kertész, János

2015-08-01

Inhomogeneous temporal processes in natural and social phenomena have been described by bursts that are rapidly occurring events within short time periods alternating with long periods of low activity. In addition to the analysis of heavy-tailed interevent time distributions, higher-order correlations between interevent times, called correlated bursts, have been studied only recently. As the underlying mechanism behind such correlated bursts is far from being fully understood, we devise a simple model for correlated bursts using a self-exciting point process with a variable range of memory. Whether a new event occurs is stochastically determined by a memory function that is the sum of decaying memories of past events. In order to incorporate the noise and/or limited memory capacity of systems, we apply two memory loss mechanisms: a fixed number or a variable number of memories. By analysis and numerical simulations, we find that too much memory effect may lead to a Poissonian process, implying that there exists an intermediate range of memory effect to generate correlated bursts comparable to empirical findings. Our conclusions provide a deeper understanding of how long-range memory affects correlated bursts.

Dark States in the Light-Harvesting complex 2 Revealed by Two-dimensional Electronic Spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ferretti, Marco; Hendrikx, Ruud; Romero, Elisabet

Energy transfer and trapping in the light harvesting antennae of purple photosynthetic bacteria is an ultrafast process, which occurs with a quantum efficiency close to unity. However the mechanisms behind this process have not yet been fully understood. Recently it was proposed that low-lying energy dark states, such as charge transfer states and polaron pairs, play an important role in the dynamics and directionality of energy transfer. However, it is difficult to directly detect those states because of their small transition dipole moment and overlap with the B850/B870 exciton bands. Here we present a new experimental approach, which combines themore » selectivity of two-dimensional electronic spectroscopy with the availability of genetically modified light harvesting complexes, to reveal the presence of those dark states in both the genetically modified and the wild-type light harvesting 2 complexes of Rhodopseudomonas palustris. In conclusion, we suggest that Nature has used the unavoidable charge transfer processes that occur when LH pigments are concentrated to enhance and direct the flow of energy.« less

Dark States in the Light-Harvesting complex 2 Revealed by Two-dimensional Electronic Spectroscopy

DOE PAGES

Ferretti, Marco; Hendrikx, Ruud; Romero, Elisabet; ...

2016-02-09

Energy transfer and trapping in the light harvesting antennae of purple photosynthetic bacteria is an ultrafast process, which occurs with a quantum efficiency close to unity. However the mechanisms behind this process have not yet been fully understood. Recently it was proposed that low-lying energy dark states, such as charge transfer states and polaron pairs, play an important role in the dynamics and directionality of energy transfer. However, it is difficult to directly detect those states because of their small transition dipole moment and overlap with the B850/B870 exciton bands. Here we present a new experimental approach, which combines themore » selectivity of two-dimensional electronic spectroscopy with the availability of genetically modified light harvesting complexes, to reveal the presence of those dark states in both the genetically modified and the wild-type light harvesting 2 complexes of Rhodopseudomonas palustris. In conclusion, we suggest that Nature has used the unavoidable charge transfer processes that occur when LH pigments are concentrated to enhance and direct the flow of energy.« less

Broadband photon pair generation in green fluorescent proteins through spontaneous four-wave mixing

PubMed Central

Shi, Siyuan; Thomas, Abu; Corzo, Neil V.; Kumar, Prem; Huang, Yuping; Lee, Kim Fook

2016-01-01

Recent studies in quantum biology suggest that quantum mechanics help us to explore quantum processes in biological system. Here, we demonstrate generation of photon pairs through spontaneous four-wave mixing process in naturally occurring fluorescent proteins. We develop a general empirical method for analyzing the relative strength of nonlinear optical interaction processes in five different organic fluorophores. Our results indicate that the generation of photon pairs in green fluorescent proteins is subject to less background noises than in other fluorophores, leading to a coincidence-to-accidental ratio ~145. As such proteins can be genetically engineered and fused to many biological cells, our experiment enables a new platform for quantum information processing in a biological environment such as biomimetic quantum networks and quantum sensors. PMID:27076032

Exploring the repeat protein universe through computational protein design

DOE PAGES

Brunette, TJ; Parmeggiani, Fabio; Huang, Po-Ssu; ...

2015-12-16

A central question in protein evolution is the extent to which naturally occurring proteins sample the space of folded structures accessible to the polypeptide chain. Repeat proteins composed of multiple tandem copies of a modular structure unit are widespread in nature and have critical roles in molecular recognition, signalling, and other essential biological processes. Naturally occurring repeat proteins have been re-engineered for molecular recognition and modular scaffolding applications. In this paper, we use computational protein design to investigate the space of folded structures that can be generated by tandem repeating a simple helix–loop–helix–loop structural motif. Eighty-three designs with sequences unrelatedmore » to known repeat proteins were experimentally characterized. Of these, 53 are monomeric and stable at 95 °C, and 43 have solution X-ray scattering spectra consistent with the design models. Crystal structures of 15 designs spanning a broad range of curvatures are in close agreement with the design models with root mean square deviations ranging from 0.7 to 2.5 Å. Finally, our results show that existing repeat proteins occupy only a small fraction of the possible repeat protein sequence and structure space and that it is possible to design novel repeat proteins with precisely specified geometries, opening up a wide array of new possibilities for biomolecular engineering.« less

Acoustic surface perception from naturally occurring step sounds of a dexterous hexapod robot

NASA Astrophysics Data System (ADS)

Cuneyitoglu Ozkul, Mine; Saranli, Afsar; Yazicioglu, Yigit

2013-10-01

Legged robots that exhibit dynamic dexterity naturally interact with the surface to generate complex acoustic signals carrying rich information on the surface as well as the robot platform itself. However, the nature of a legged robot, which is a complex, hybrid dynamic system, renders the more common approach of model-based system identification impractical. The present paper focuses on acoustic surface identification and proposes a non-model-based analysis and classification approach adopted from the speech processing literature. A novel feature set composed of spectral band energies augmented by their vector time derivatives and time-domain averaged zero crossing rate is proposed. Using a multi-dimensional vector classifier, these features carry enough information to accurately classify a range of commonly occurring indoor and outdoor surfaces without using of any mechanical system model. A comparative experimental study is carried out and classification performance and computational complexity are characterized. Different feature combinations, classifiers and changes in critical design parameters are investigated. A realistic and representative acoustic data set is collected with the robot moving at different speeds on a number of surfaces. The study demonstrates promising performance of this non-model-based approach, even in an acoustically uncontrolled environment. The approach also has good chance of performing in real-time.

Identification of naturally occurring hybrids between two overexploited sciaenid species along the South African coast.

PubMed

Mirimin, L; Kerwath, S E; Macey, B M; Bester-van der Merwe, A E; Lamberth, S J; Bloomer, P; Roodt-Wilding, R

2014-07-01

Hybridisation between fish species can play a significant role in evolutionary processes and can influence management and conservation planning, however, this phenomenon has been widely understudied, especially in marine organisms. The distribution limits of two sciaenid species (silver kob, Argyrosomus inodorus, and dusky kob, A. japonicus) partly overlap along the South African coast, where both species have undergone severe depletion due to overfishing. Following the identification of a number of possible cases of species misidentification or hybridisation (21 out of 422 individuals), nuclear and mitochondrial DNA data (12microsatellite loci and 562bp of the COI gene) were analysed to investigate the genetic composition of these individuals. Results indicated a field-based species misidentification rate of approximately 2.8% and a rate of natural hybridisation of 0.7%. Interestingly, all hybrid fish resulted from first-generation (F1) hybridisation events, which occurred exclusively between silver kob females and dusky kob males. Whether hybridisation is the result of natural events (such as secondary contact following a shift in distribution range), or anthropogenic activities (size-selective pressure due to overfishing), these findings have important implications for critical recovery and future management of these species in the wild. Copyright © 2014 Elsevier Inc. All rights reserved.

A natural diarylheptanoid promotes neuronal differentiation via activating ERK and PI3K-Akt dependent pathways.

PubMed

Tang, G; Dong, X; Huang, X; Huang, X-J; Liu, H; Wang, Y; Ye, W-C; Shi, L

2015-09-10

Neuronal differentiation is a critical developmental process that determines accurate synaptic connection and circuit wiring. A wide variety of naturally occurring compounds have been shown as promising drug leads for the generation and differentiation of neurons. Here we report that a diarylheptanoid from the plant Alpinia officinarum, 7-(4-hydroxyphenyl)-1-phenyl-4E-hepten-3-one (Cpd 1), exhibited potent activities in neuronal differentiation and neurite outgrowth. Cpd 1 induced differentiation of neuroblastoma Neuro-2a cells into a neuron-like morphology, and accelerated the establishment of axon-dendrite polarization of cultured hippocampal neurons. Moreover, Cpd 1 promoted neurite extension in both Neuro-2a cells and neurons. We showed that the effects of Cpd 1 on neuronal differentiation and neurite growth were specifically dependent on the activation of extracellular signal-regulated kinases (ERKs) and phosphoinositide 3-kinase (PI3K)-Akt signaling pathways. Importantly, intraperitoneal administration of Cpd 1 promoted the differentiation of new-born progenitor cells into mature neurons in the adult hippocampal dentate gyrus. Collectively, this study identifies a naturally occurring diarylheptanoid with beneficial effects on neuronal differentiation and neurite outgrowth in vitro and in vivo. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

Comparative Toxicology of Libby Amphibole and Naturally Occurring Asbestos

EPA Science Inventory

Summary sentence: Comparative toxicology of Libby amphibole (LA) and site-specific naturally occurring asbestos (NOA) provides new insights on physical properties influencing health effects and mechanisms of asbestos-induced inflammation, fibrosis, and tumorigenesis.Introduction/...

Naturally Occurring Radon and 120(h) transfers

EPA Pesticide Factsheets

This page contains a discussion regarding how the presence of naturally occurring radon on closing military bases affects the United States' ability to transfer parcels under §120(h) (3) and §120(h) (4).

Natural hazard impact on the technosphere: "blackouts

NASA Astrophysics Data System (ADS)

Petrova, E. G.

2012-04-01

In recent years, natural-technological accidents (NTA) and disasters are increasing in their number and severity all over the world. The term "natural-technological accident (disaster)" applies for an accident (disaster) in the technosphere triggered by any natural process or phenomenon. Their growth is caused, on the one hand, by observed increasing in the frequency and intensity of some natural hazards and hazardous events due to climate change and, on the other hand, by a growing complication of the modern technosphere exposed to natural impacts and advancement of economic activities into the area at natural risk. The most large-scaled natural-technological disaster happened on March 11, 2011 in Japan, as a result of a massive earthquake and tsunami that caused a number of serious technological accidents, including accidents at "Fukushima-1" nuclear power plant, etc. Severe social, ecological and economic consequences of large-scaled NTA make investigation of these events especially important. The most frequent among NTA occurring in Russia are breakdowns in electric power supply systems that lead to so-called "blackouts" (accidental power outages). They are mainly caused by strong winds, snowstorms, deposition of ice, sleet, and snow, rainfalls, floods, and hailstones. Among other triggers earthquakes, hard frost, fierce heat, thunderstorms, landslides, snow avalanches, and debris flows should be mentioned. The great part of transmission facilities in Russia falls on overhead lines that are especially vulnerable to natural impacts. In general, natural triggers are responsible for more than 70 percent of all accidents in power supply systems. They occur more often in Far East, in the Southern and North-Western federal districts, and in some regions of the Central Russia, which are prone to hurricanes, cyclones, snowstorms, and heavy rainfalls accompanying by hailstones, icing, and sleet. A distinctive feature of these events is their synergistic nature, as power outages can cause a chain of other accidents at heat- and water supply, industrial plants, transport and communication facilities, producing so-called "domino effect". A modernization of facilities, replacement of overhead lines by underground cables and protection from falling trees can reduce the problem.

A cellular automata based FPGA realization of a new metaheuristic bat-inspired algorithm

NASA Astrophysics Data System (ADS)

Progias, Pavlos; Amanatiadis, Angelos A.; Spataro, William; Trunfio, Giuseppe A.; Sirakoulis, Georgios Ch.

2016-10-01

Optimization algorithms are often inspired by processes occuring in nature, such as animal behavioral patterns. The main concern with implementing such algorithms in software is the large amounts of processing power they require. In contrast to software code, that can only perform calculations in a serial manner, an implementation in hardware, exploiting the inherent parallelism of single-purpose processors, can prove to be much more efficient both in speed and energy consumption. Furthermore, the use of Cellular Automata (CA) in such an implementation would be efficient both as a model for natural processes, as well as a computational paradigm implemented well on hardware. In this paper, we propose a VHDL implementation of a metaheuristic algorithm inspired by the echolocation behavior of bats. More specifically, the CA model is inspired by the metaheuristic algorithm proposed earlier in the literature, which could be considered at least as efficient than other existing optimization algorithms. The function of the FPGA implementation of our algorithm is explained in full detail and results of our simulations are also demonstrated.

Preparation of Magnesium, Cobalt and Nickel Ferrite Nanoparticles from Metal Oxides using Deep Eutectic Solvents.

PubMed

Söldner, Anika; Zach, Julia; Iwanow, Melanie; Gärtner, Tobias; Schlosser, Marc; Pfitzner, Arno; König, Burkhard

2016-09-05

Natural deep eutectic solvents (DESs) dissolve simple metal oxides and are used as a reaction medium to synthesize spinel-type ferrite nanoparticles MFe2 O4 (M=Mg, Zn, Co, Ni). The best results for phase-pure spinel ferrites are obtained with the DES consisting of choline chloride (ChCl) and maleic acid. By employing DESs, the reactions proceed at much lower temperatures than usual for the respective solid-phase reactions of the metal oxides and at the same temperatures as synthesis with comparable calcination processes using metal salts. The method therefore reduces the overall required energy for the nanoparticle synthesis. Thermogravimetric analysis shows that the thermolysis process of the eutectic melts in air occurs in one major step. The phase-pure spinel-type ferrite particles are thoroughly characterized by X-ray diffraction, diffuse-reflectance UV/Vis spectroscopy, and scanning electron microscopy. The properties of the obtained nanoparticles are shown to be comparable to those obtained by other methods, illustrating the potential of natural DESs for processing metal oxides. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Collaborative encoding and memory accuracy: examining the effects of interactive components of co-construction processes.

PubMed

Foley, Mary Ann; Fried, Adina Rachel; Cowan, Emily; Bays, Rebecca Brooke

2014-01-01

In 2 experiments, the effect of collaborative encoding on memory was examined by testing 2 interactive components of co-construction processes. One component focused on the nature of the interactive exchange between collaborators: As the partners worked together to create descriptions about ways to interact with familiar objects, constraints were imposed on the interactions by requiring them to take turns (Experiment 1) or to interact without constraints (Experiment 2). The nature of the relationship between partners was manipulated as well by including 2 pair types, friends or unfamiliar peers (Experiments 1 and 2). Interactive component effects were found to influence spontaneous activations through content analyses of participants' descriptions, the patterns of false recognition errors, and the relationship between content and errors. The findings highlight the value of examining the content of participants' collaborative efforts when assessing the effects of collaborative encoding on memory and point to mechanisms mediating collaboration's effects. Because the interactions occurred within the context of an imagery generation task, the findings are also intriguing because of their implications for the use of guided imagery techniques that incorporate co-construction processes.

Production of a Suitable Antibody and an Enzyme Immunoassay Kit for the Field Detection of T-2 Toxin

DTIC Science & Technology

1983-10-25

Known to naturally occur on plants including food products. £> These trichothecenes are highly toxic to eukaryotic cells and are anong the most...Activities and Detection of Naturally O* Occurring 12,13-Epoxy-9-Trichothecenes," Clin. Tbxicol., 5, pp. 495-515. E* 3. Y. Ueno, M. Makajima, K. Sakei, K...North-Holland, N.Y. -13- i 6. S. V. Pathre, C. J. Mirocha (1977) Assay Methods for Trichothecenes and J; Review of Their Natural Occurence in: J. V