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Sample records for natural background approach

  1. Teaching about Natural Background Radiation

    ERIC Educational Resources Information Center

    Al-Azmi, Darwish; Karunakara, N.; Mustapha, Amidu O.

    2013-01-01

    Ambient gamma dose rates in air were measured at different locations (indoors and outdoors) to demonstrate the ubiquitous nature of natural background radiation in the environment and to show that levels vary from one location to another, depending on the underlying geology. The effect of a lead shield on a gamma radiation field was also…

  2. Teaching about Natural Background Radiation

    ERIC Educational Resources Information Center

    Al-Azmi, Darwish; Karunakara, N.; Mustapha, Amidu O.

    2013-01-01

    Ambient gamma dose rates in air were measured at different locations (indoors and outdoors) to demonstrate the ubiquitous nature of natural background radiation in the environment and to show that levels vary from one location to another, depending on the underlying geology. The effect of a lead shield on a gamma radiation field was also…

  3. Teaching about natural background radiation

    NASA Astrophysics Data System (ADS)

    Al-Azmi, Darwish; Karunakara, N.; Mustapha, Amidu O.

    2013-07-01

    Ambient gamma dose rates in air were measured at different locations (indoors and outdoors) to demonstrate the ubiquitous nature of natural background radiation in the environment and to show that levels vary from one location to another, depending on the underlying geology. The effect of a lead shield on a gamma radiation field was also demonstrated to emphasize the important role of shielding in radiation protection. The measurements were carried out with a Geiger-Muller (GM)-based dosimeter and a NaI scintillation gamma-ray spectrometer, which are normally available in physics laboratories. Radioactivity in household materials was demonstrated using a gas mantle as an example.

  4. Ambient background particulate composition, outdoor natural background: interferents/clutter

    NASA Astrophysics Data System (ADS)

    Paterno, Dorothea

    2012-06-01

    It has proven a very difficult task to discriminate an actual BW threat from the natural occurring ambient particulate aerosol, which includes a significant fraction of particles consisting of mixed mineral and biological material. The interferent particles [clutter] (bio and non bio) concentration varies widely both by location, weather and season and diurnally. Naturally occurring background particulates are composed of fungal and bacterial spores both fragments and components, plant fragments and debris, animal fragments and debris, all of which may be associated with inert dust or combustion material. Some or all of which could also be considered to be an interferent to a biological warfare detector and cause these biodector systems to cause False Alarms by non specific BW bio detectors. I will share analysis of current long term background data sets.

  5. Speech recognition in natural background noise.

    PubMed

    Meyer, Julien; Dentel, Laure; Meunier, Fanny

    2013-01-01

    In the real world, human speech recognition nearly always involves listening in background noise. The impact of such noise on speech signals and on intelligibility performance increases with the separation of the listener from the speaker. The present behavioral experiment provides an overview of the effects of such acoustic disturbances on speech perception in conditions approaching ecologically valid contexts. We analysed the intelligibility loss in spoken word lists with increasing listener-to-speaker distance in a typical low-level natural background noise. The noise was combined with the simple spherical amplitude attenuation due to distance, basically changing the signal-to-noise ratio (SNR). Therefore, our study draws attention to some of the most basic environmental constraints that have pervaded spoken communication throughout human history. We evaluated the ability of native French participants to recognize French monosyllabic words (spoken at 65.3 dB(A), reference at 1 meter) at distances between 11 to 33 meters, which corresponded to the SNRs most revealing of the progressive effect of the selected natural noise (-8.8 dB to -18.4 dB). Our results showed that in such conditions, identity of vowels is mostly preserved, with the striking peculiarity of the absence of confusion in vowels. The results also confirmed the functional role of consonants during lexical identification. The extensive analysis of recognition scores, confusion patterns and associated acoustic cues revealed that sonorant, sibilant and burst properties were the most important parameters influencing phoneme recognition. . Altogether these analyses allowed us to extract a resistance scale from consonant recognition scores. We also identified specific perceptual consonant confusion groups depending of the place in the words (onset vs. coda). Finally our data suggested that listeners may access some acoustic cues of the CV transition, opening interesting perspectives for future studies.

  6. Speech Recognition in Natural Background Noise

    PubMed Central

    Meyer, Julien; Dentel, Laure; Meunier, Fanny

    2013-01-01

    In the real world, human speech recognition nearly always involves listening in background noise. The impact of such noise on speech signals and on intelligibility performance increases with the separation of the listener from the speaker. The present behavioral experiment provides an overview of the effects of such acoustic disturbances on speech perception in conditions approaching ecologically valid contexts. We analysed the intelligibility loss in spoken word lists with increasing listener-to-speaker distance in a typical low-level natural background noise. The noise was combined with the simple spherical amplitude attenuation due to distance, basically changing the signal-to-noise ratio (SNR). Therefore, our study draws attention to some of the most basic environmental constraints that have pervaded spoken communication throughout human history. We evaluated the ability of native French participants to recognize French monosyllabic words (spoken at 65.3 dB(A), reference at 1 meter) at distances between 11 to 33 meters, which corresponded to the SNRs most revealing of the progressive effect of the selected natural noise (−8.8 dB to −18.4 dB). Our results showed that in such conditions, identity of vowels is mostly preserved, with the striking peculiarity of the absence of confusion in vowels. The results also confirmed the functional role of consonants during lexical identification. The extensive analysis of recognition scores, confusion patterns and associated acoustic cues revealed that sonorant, sibilant and burst properties were the most important parameters influencing phoneme recognition. . Altogether these analyses allowed us to extract a resistance scale from consonant recognition scores. We also identified specific perceptual consonant confusion groups depending of the place in the words (onset vs. coda). Finally our data suggested that listeners may access some acoustic cues of the CV transition, opening interesting perspectives for future studies

  7. A review on natural background radiation

    PubMed Central

    Shahbazi-Gahrouei, Daryoush; Gholami, Mehrdad; Setayandeh, Samaneh

    2013-01-01

    The world is naturally radioactive and approximately 82% of human-absorbed radiation doses, which are out of control, arise from natural sources such as cosmic, terrestrial, and exposure from inhalation or intake radiation sources. In recent years, several international studies have been carried out, which have reported different values regarding the effect of background radiation on human health. Gamma radiation emitted from natural sources (background radiation) is largely due to primordial radionuclides, mainly 232Th and 238U series, and their decay products, as well as 40K, which exist at trace levels in the earth's crust. Their concentrations in soil, sands, and rocks depend on the local geology of each region in the world. Naturally occurring radioactive materials generally contain terrestrial-origin radionuclides, left over since the creation of the earth. In addition, the existence of some springs and quarries increases the dose rate of background radiation in some regions that are known as high level background radiation regions. The type of building materials used in houses can also affect the dose rate of background radiations. The present review article was carried out to consider all of the natural radiations, including cosmic, terrestrial, and food radiation. PMID:24223380

  8. Background radiation: natural and man-made.

    PubMed

    Thorne, M C

    2003-03-01

    A brief overview and comparison is given of dose rates arising from natural background radiation and the fallout from atmospheric testing of nuclear weapons. Although there are considerable spatial variations in exposure to natural background radiation, it is useful to give estimates of worldwide average overall exposures from the various components of that background. Cosmic-ray secondaries of low linear energy transfer (LET), mainly muons and photons, deliver about 280 microSv a(-1). Cosmic-ray neutrons deliver about another 100 microSv a(-1). These low- and high-LET exposures are relatively uniform to the whole body. The effective dose rate from cosmogenic radionuclides is dominated by the contribution of 12 microSv a(-1) from 14C. This is due to relatively uniform irradiation of all organs and tissues from low-energy beta particles. Primordial radionuclides and their progeny (principally the 238U and 232Th series, and 40K) contribute about 480 microSv a(-1) of effective dose by external irradiation. This is relatively uniform photon irradiation of the whole body. Internally incorporated 40K contributes a further 165 microSv a(-1) of effective dose in adults, mainly from beta particles, but with a significant gamma component. Equivalent doses from 40K are somewhat higher in muscle than other soft tissues, but the distinction is less than a factor of three. Uranium and thorium series radionuclides give rise to an average effective dose rate of around 120 microSv a(-1). This includes a major alpha particle component, and exposures of radiosensitive tissues in lung, liver, kidney and the skeleton are recognised as important contributors to effective dose. Overall, these various sources give a worldwide average effective dose rate of about 1160 microSv a(-1). Exposure to 222Rn, 220Rn and their short-lived progeny has to be considered separately. This is very variable both within and between countries. For 222Rn and its progeny, a worldwide average effective dose

  9. Sinning against nature: the theory of background conditions.

    PubMed

    Blackford, R

    2006-11-01

    Debates about the moral and political acceptability of particular sexual practices and new technologies often include appeals to a supposed imperative to follow nature. If nature is understood as the totality of all phenomena or as those things that are not artificial, there is little prospect of developing a successful argument to impugn interference with it or sinning against it. At the same time, there are serious difficulties with approaches that seek to identify "proper" human functioning. An alternative approach is to understand interference with nature as acting in a manner that threatens basic background conditions to human choice. Arguably, the theory of background conditions helps explain much of the hostility to practices and technologies that allegedly sin against nature. The theory does not, however, entail that appeals to nature are relevant or rational. Such appeals should be subjected to sceptical scrutiny. Indeed, the theory suggests that arguments against practices and technologies that can be seen as contrary to nature sometimes exercise a psychological attraction that is disproportional to their actual cogency.

  10. Sinning against nature: the theory of background conditions

    PubMed Central

    Blackford, R

    2006-01-01

    Debates about the moral and political acceptability of particular sexual practices and new technologies often include appeals to a supposed imperative to follow nature. If nature is understood as the totality of all phenomena or as those things that are not artificial, there is little prospect of developing a successful argument to impugn interference with it or sinning against it. At the same time, there are serious difficulties with approaches that seek to identify "proper" human functioning. An alternative approach is to understand interference with nature as acting in a manner that threatens basic background conditions to human choice. Arguably, the theory of background conditions helps explain much of the hostility to practices and technologies that allegedly sin against nature. The theory does not, however, entail that appeals to nature are relevant or rational. Such appeals should be subjected to sceptical scrutiny. Indeed, the theory suggests that arguments against practices and technologies that can be seen as contrary to nature sometimes exercise a psychological attraction that is disproportional to their actual cogency. PMID:17074819

  11. Chromo-natural model in anisotropic background

    SciTech Connect

    Maleknejad, Azadeh; Erfani, Encieh E-mail: eerfani@ipm.ir

    2014-03-01

    In this work we study the chromo-natural inflation model in the anisotropic setup. Initiating inflation from Bianchi type-I cosmology, we analyze the system thoroughly during the slow-roll inflation, from both analytical and numerical points of view. We show that the isotropic FRW inflation is an attractor of the system. In other words, anisotropies are damped within few e-folds and the chromo-natural model respects the cosmic no-hair conjecture. Furthermore, we demonstrate that in the slow-roll limit, the anisotropies in both chromo-natural and gauge-flation models share the same dynamics.

  12. Assessment of natural background levels in potentially contaminated coastal aquifers.

    PubMed

    Molinari, A; Chidichimo, F; Straface, S; Guadagnini, A

    2014-04-01

    The estimation of natural background levels (NBLs) of dissolved concentrations of target chemical species in subsurface reservoirs relies on a proper assessment of the effects of forcing terms driving flow and transport processes taking place within the system and whose dynamics drive background concentration values. We propose coupling methodologies based on (a) global statistical analyses and (b) numerical modeling of system dynamics to distinguish between the impacts of different types of external forcing components influencing background concentration values. We focus on the joint application of a statistical methodology based on Component Separation and experimental/numerical modeling studies of groundwater flow and transport for the NBL estimation of selected chemical species in potentially contaminated coastal aquifers. We consider a site which is located in Calabria, Italy, and constitutes a typical example of a Mediterranean coastal aquifer which has been subject to intense industrial development. Our study is keyed to the characterization of NBLs of manganese and sulfate and is geared to the proper identification of the importance of a natural external forcing (i.e., seawater intrusion) on NBL assessment. Results from the Component Separation statistical approach are complemented by numerical simulations of the advective-dispersive processes that could influence the distribution of chemical species (i.e., sulfate) within the system. Estimated NBLs for manganese are consistent with the geochemical composition of soil samples. While Component Separation ascribes the largest detected sulfate concentrations to anthropogenic sources, our numerical modeling analysis suggests that they are mainly related to the natural process of seawater intrusion. Our results indicate that the use of statistical methodologies in complex groundwater systems should be assisted by a detailed characterization of the dynamics of natural (and/or induced) processes to distinguish

  13. Study of Natural Background Radiation around Gurvanbulag Uranium Deposit Area

    SciTech Connect

    Enkhbat, N.; Norov, N.; Khuukhenkhuu, G.; Otgooloi, B.; Bat-Erdene, B.

    2009-03-31

    In this work, we will show the study of natural background radiation level around the Gurvanbulag (GB) uranium deposit area in the eastern part of Mongolia. We collected environmental soil samples from 102 points around GB Uranium deposit. Collected samples were measured by HPGe gamma spectrometer at Nuclear Research Center, National University of Mongolia. The averaged activity concentrations of Ra-226, Th-232, K-40, and Cs-137 were 37.1, 29, 939, and 17.7 Bq/kg, respectively.

  14. Statistical Modeling of Natural Backgrounds in Hyperspectral LWIR Data

    DTIC Science & Technology

    2016-09-06

    Statistical Modeling of Natural Backgrounds in Hyperspectral LWIR Data Eric Truslowa, Dimitris Manolakisa, Thomas Cooleyb, and Joseph Meolac aMIT...87117 cSensors Directorate, Air Force Research Laboratory, Wright-Patterson AFB, OH 45433 Hyperspectral sensors operating in the long wave infrared (LWIR...investigated. In this paper, we investigate modeling hyperspectral LWIR data using a statistical mixture model for the emissivity and surface

  15. Image Discrimination Models Predict Object Detection in Natural Backgrounds

    NASA Technical Reports Server (NTRS)

    Ahumada, Albert J., Jr.; Rohaly, A. M.; Watson, Andrew B.; Null, Cynthia H. (Technical Monitor)

    1994-01-01

    Object detection involves looking for one of a large set of object sub-images in a large set of background images. Image discrimination models only predict the probability that an observer will detect a difference between two images. In a recent study based on only six different images, we found that discrimination models can predict the relative detectability of objects in those images, suggesting that these simpler models may be useful in some object detection applications. Here we replicate this result using a new, larger set of images. Fifteen images of a vehicle in an other-wise natural setting were altered to remove the vehicle and mixed with the original image in a proportion chosen to make the target neither perfectly recognizable nor unrecognizable. The target was also rotated about a vertical axis through its center and mixed with the background. Sixteen observers rated these 30 target images and the 15 background-only images for the presence of a vehicle. The likelihoods of the observer responses were computed from a Thurstone scaling model with the assumption that the detectabilities are proportional to the predictions of an image discrimination model. Three image discrimination models were used: a cortex transform model, a single channel model with a contrast sensitivity function filter, and the Root-Mean-Square (RMS) difference of the digital target and background-only images. As in the previous study, the cortex transform model performed best; the RMS difference predictor was second best; and last, but still a reasonable predictor, was the single channel model. Image discrimination models can predict the relative detectabilities of objects in natural backgrounds.

  16. Image Discrimination Models Predict Object Detection in Natural Backgrounds

    NASA Technical Reports Server (NTRS)

    Ahumada, Albert J., Jr.; Rohaly, A. M.; Watson, Andrew B.; Null, Cynthia H. (Technical Monitor)

    1994-01-01

    Object detection involves looking for one of a large set of object sub-images in a large set of background images. Image discrimination models only predict the probability that an observer will detect a difference between two images. In a recent study based on only six different images, we found that discrimination models can predict the relative detectability of objects in those images, suggesting that these simpler models may be useful in some object detection applications. Here we replicate this result using a new, larger set of images. Fifteen images of a vehicle in an other-wise natural setting were altered to remove the vehicle and mixed with the original image in a proportion chosen to make the target neither perfectly recognizable nor unrecognizable. The target was also rotated about a vertical axis through its center and mixed with the background. Sixteen observers rated these 30 target images and the 15 background-only images for the presence of a vehicle. The likelihoods of the observer responses were computed from a Thurstone scaling model with the assumption that the detectabilities are proportional to the predictions of an image discrimination model. Three image discrimination models were used: a cortex transform model, a single channel model with a contrast sensitivity function filter, and the Root-Mean-Square (RMS) difference of the digital target and background-only images. As in the previous study, the cortex transform model performed best; the RMS difference predictor was second best; and last, but still a reasonable predictor, was the single channel model. Image discrimination models can predict the relative detectabilities of objects in natural backgrounds.

  17. Effect of natural background radiation on dermatoglyphic traits.

    PubMed

    Bhasin, M K; Malik, S L; Grewal, M S; Singh, I P; Sudarshan, K J; Kochupillai, N; Verma, I C

    1980-01-01

    Long term exposure to natural background radiation could cause gross abnormalities in individuals and at the population level. Studies conducted on the coastal Kerala population which is known to be receiving fifteen times the normal permissible dose of radiation support this. This study aims at understanding the deviations, if any, in the normal human variation as a result of such high natural radiation. A detailed quantitative and qualitative dermatoglyphic study was done on two communities i.e. Hindus and Christians, living separately in the radiation area. The significant differences were observed between control and exposed groups with regard to d-t ridge count, distances c-t and angle atd. The susceptibility of the axial triradius to environmental distrubances is discussed.

  18. The ROSCOE MANUAL. Volume 27: Natural background radiation

    NASA Astrophysics Data System (ADS)

    Hamlin, D. A.; Schoonover, M. R.

    1980-07-01

    The Natural Background Radiation Module computes the Earth's natural upwelling spectral radiance (from 2 to 5 micrometers) by averaging over paths in an Earth-tangent cone with vertex at each selected altitude. The processes contributing to the radiance are emission from air, Earth's surface, and clouds and reflection of solar radiation from Earth's surface and clouds; attenuation is by molecules and aerosols. The Module integrates ROSCOE-IR models for atmosphere, atmospheric thermal emission, molecular transmittance, aerosols, clouds, Earth's surface characterization and radiance, solar radiation, and upwelling natural radiation. The last 3 models are documented fully; other models (three of which were developed by other organizations) are documented mainly in terms of functions performed, inputs, and outputs. The user selects the modeled Earth's surface from one of seven categories (with possibly an associated descriptor): Lambertian surface (and diffuse reflectance), wind-ruffled water (and wind speed), snow (and its age parameter), sand, soil, foliage, and urban material (and degree-of-urbanization parameter).

  19. Using Natural Approach Teaching Techniques.

    ERIC Educational Resources Information Center

    Whitman, Charles

    1986-01-01

    Describes a beginning foreign language class applying the principles of Stephen Krashen's "Natural Approach" and James Asher's "Total Physical Response" method. Initially students carry out the instructor's commands in the form of actions rather than being required to speak. In later stages role play and simple discussions are…

  20. Using Natural Approach Teaching Techniques.

    ERIC Educational Resources Information Center

    Whitman, Charles

    1986-01-01

    Describes a beginning foreign language class applying the principles of Stephen Krashen's "Natural Approach" and James Asher's "Total Physical Response" method. Initially students carry out the instructor's commands in the form of actions rather than being required to speak. In later stages role play and simple discussions are…

  1. Background subtraction approach based on independent component analysis.

    PubMed

    Jiménez-Hernández, Hugo

    2010-01-01

    In this work, a new approach to background subtraction based on independent component analysis is presented. This approach assumes that background and foreground information are mixed in a given sequence of images. Then, foreground and background components are identified, if their probability density functions are separable from a mixed space. Afterwards, the components estimation process consists in calculating an unmixed matrix. The estimation of an unmixed matrix is based on a fast ICA algorithm, which is estimated as a Newton-Raphson maximization approach. Next, the motion components are represented by the mid-significant eigenvalues from the unmixed matrix. Finally, the results show the approach capabilities to detect efficiently motion in outdoors and indoors scenarios. The results show that the approach is robust to luminance conditions changes at scene.

  2. In-mine testing of a natural background sensor, part B

    NASA Technical Reports Server (NTRS)

    Martzloff, F. D.

    1981-01-01

    The capability of a natural background sensor for measuring the thickness of top coal on a longwall face was examined. The limitations on the time during which tests could be performed, and the roof conditions, did not produce readings of top coal measurements during the shearer operation. It was demonstrated that the system is capable to survive operating conditions in the mine environment, while the static tests confirmed that the natural background sensor approach is a valid method of measuring top coal thickness in mines where the roof rock provides a constant radiation level. It is concluded that the practical results will improve sequent development of an integrated vertical control system which is information from the natural background system.

  3. Using epicenter location to differentiate events from natural background seismicity

    SciTech Connect

    Myers, S C; Walter, W R

    1999-07-26

    Efforts to more effectively monitor the Comprehensive Nuclear-Test-Ban Treaty (commonly referred to as the CTBT) include research into methods of seismic discrimination. The most common seismic discriminants exploit differences in seismic amplitude for differing source types. Amplitude discriminants are quite effective when wave-propagation (a.k.a. path) effects are properly accounted for. However, because path effects can be exceedingly complex, path calibration is often accomplished empirically by spatially interpolating amplitude characteristics for a set of calibration earthquakes with techniques like Bayesian kriging. As a result, amplitude discriminants can be highly effective when natural seismicity provides sufficient event coverage to characterize a region. However, amplitude discrimination can become less effective for events that are far from historical (path-calibration) events. It is intuitive that events occurring at a distance from historical seismicity patterns are inherently suspect. However, quantifying the degree to which a particular event is unexpected could be of great utility in CTBT monitoring. Epicenter location is commonly used as a qualitative discriminant. For instance, if a seismic event is located in the deep ocean, then the event is generally considered to be an earthquake. Such qualitative uses of seismic location have great utility; however, a quantitative method to differentiate events from the natural pattern of seismicity could significantly advance the applicability of location as a discriminant for source type. Clustering of earthquake epicenters is the underlying aspect of earthquake seismicity that allows for an epicenter-based discriminant, and we explore the use of fractal characterization of clustering to characterize seismicity patters. We then evaluate the likelihood that an event at any given location is drawn from the background population. The use of this technique can help to identifying events that are inconsistent

  4. Estimating natural background groundwater chemistry, Questa molybdenum mine, New Mexico

    USGS Publications Warehouse

    Verplanck, Phillip L.; Nordstrom, D. Kirk; Plumlee, Geoffrey S.; Walker, Bruce M.; Morgan, Lisa A.; Quane, Steven L.

    2010-01-01

    This 2 1/2 day field trip will present an overview of a U.S. Geological Survey (USGS) project whose objective was to estimate pre-mining groundwater chemistry at the Questa molybdenum mine, New Mexico. Because of intense debate among stakeholders regarding pre-mining groundwater chemistry standards, the New Mexico Environment Department and Chevron Mining Inc. (formerly Molycorp) agreed that the USGS should determine pre-mining groundwater quality at the site. In 2001, the USGS began a 5-year, multidisciplinary investigation to estimate pre-mining groundwater chemistry utilizing a detailed assessment of a proximal natural analog site and applied an interdisciplinary approach to infer pre-mining conditions. The trip will include a surface tour of the Questa mine and key locations in the erosion scar areas and along the Red River. The trip will provide participants with a detailed understanding of geochemical processes that influence pre-mining environmental baselines in mineralized areas and estimation techniques for determining pre-mining baseline conditions.

  5. Is natural background or radiation from nuclear power plants leukemogenic

    SciTech Connect

    Cronkite, E.P.

    1989-01-01

    The objective in this review is to provide some facts about normal hemopoietic cell proliferation relevant to leukemogenesis, physical, chemical, and biological facts about radiation effects with the hope that each person will be able to decide for themselves whether background radiation or emissions from nuclear power plants and facilities significantly add to the spontaneous leukemia incidence. 23 refs., 1 tab.

  6. Natural approach to quantum dissipation

    NASA Astrophysics Data System (ADS)

    Taj, David; Öttinger, Hans Christian

    2015-12-01

    The dissipative dynamics of a quantum system weakly coupled to one or several reservoirs is usually described in terms of a Lindblad generator. The popularity of this approach is certainly due to the linear character of the latter. However, while such linearity finds justification from an underlying Hamiltonian evolution in some scaling limit, it does not rely on solid physical motivations at small but finite values of the coupling constants, where the generator is typically used for applications. The Markovian quantum master equations we propose are instead supported by very natural thermodynamic arguments. They themselves arise from Markovian master equations for the system and the environment which preserve factorized states and mean energy and generate entropy at a non-negative rate. The dissipative structure is driven by an entropic map, called modular, which introduces nonlinearity. The generated modular dynamical semigroup (MDS) guarantees for the positivity of the time evolved state the correct steady state properties, the positivity of the entropy production, and a positive Onsager matrix with symmetry relations arising from Green-Kubo formulas. We show that the celebrated Davies Lindblad generator, obtained through the Born and the secular approximations, generates a MDS. In doing so we also provide a nonlinear MDS which is supported by a weak coupling argument and is free from the limitations of the Davies generator.

  7. [Hereditary background and natural history in glucose-intolerance group].

    PubMed

    Ito, C

    1996-10-01

    For non-obese IGT, frequency of 1st degree DM relatives was 29.9%, a rate higher than normal. NIDDM development rate was higher in IGT with family history of DM (86.9/1000 PY) than in IGT without family history (75.4/1000PY). For IGT-2 (2hr. PG > or = 170 mg/dl), the rate was higher in the group with family history (140.1/1000 PY) than that without family history (113.6/1000 PY). The odds ratio for NIDDM was 1.76 with obesity and 1.55 with family history. With regard to the natural course, plasma glucose (PG) increased slowly with rising of IRI over a long period, then PG increased suddenly without rising IRI and reached NIDDM onset. From these results, intervention trials for prevention of NIDDM are possible during long glucose-intolerance period.

  8. A novel approach to model EPIC variable background

    NASA Astrophysics Data System (ADS)

    Marelli, M.; De Luca, A.; Salvetti, D.; Belfiore, A.; Pizzocaro, D.

    2016-06-01

    In the past years XMM-Newton revolutionized our way to look at the X-ray sky. With more than 200 Ms of exposure, it allowed for numerous discoveries in every field of astronomy. Unfortunately, about 35% of the observing time is badly affected by soft proton flares, with background increasing by orders of magnitudes hampering any classical analysis of field sources. One of the main aim of the EXTraS ("Exploring the X-ray Transient and variable Sky") project is to characterise the variability of XMM-Newton sources within each single observation, including periods of high background. This posed severe challenges. I will describe a novel approach that we implemented within the EXTraS project to produce background-subtracted light curves, that allows to treat the case of very faint sources and very large proton flares. EXTraS light curves will be soon released to the community, together with new tools that will allow the user to reproduce EXTraS results, as well as to extend a similar analysis to future data. Results of this work (including an unprecedented characterisation of the soft proton phenomenon and instrument response) will also serve as a reference for future missions and will be particularly relevant for the Athena observatory.

  9. Low level activity determination by means of gamma spectrometry with respect to the natural background fluctuation.

    PubMed

    Dragounová, Lenka; Rulík, Petr

    2013-11-01

    The determination of low level activities of natural radionuclides from the uranium and thorium series by gamma-spectrometry faces the problem of proper natural background subtraction. Background fluctuation can cause differences in activity determination. Also the minimum detectable activity (MDA) of natural and artificial radionuclides can be influenced by background fluctuation. In this paper, results of the background fluctuation of shielded HPGe detectors with relative efficiency of 50-150% are presented together with the assessment of its influence on the determination of natural and artificial radionuclides. © 2013 Elsevier Ltd. All rights reserved.

  10. Hidden in the background: a local approach to CMB anomalies

    NASA Astrophysics Data System (ADS)

    Bueno Sánchez, Juan C.

    2016-09-01

    We investigate a framework aiming to provide a common origin for the large-angle anomalies detected in the Cosmic Microwave Background (CMB), which are hypothesized as the result of the statistical inhomogeneity developed by different isocurvature fields of mass m~ H present during inflation. The inhomogeneity arises as the combined effect of (i) the initial conditions for isocurvature fields (obtained after a fast-roll stage finishing many e-foldings before cosmological scales exit the horizon), (ii) their inflationary fluctuations and (iii) their coupling to other degrees of freedom. Our case of interest is when these fields (interpreted as the precursors of large-angle anomalies) leave an observable imprint only in isolated patches of the Universe. When the latter intersect the last scattering surface, such imprints arise in the CMB. Nevertheless, due to their statistically inhomogeneous nature, these imprints are difficult to detect, for they become hidden in the background similarly to the Cold Spot. We then compute the probability that a single isocurvature field becomes inhomogeneous at the end of inflation and find that, if the appropriate conditions are given (which depend exclusively on the preexisting fast-roll stage), this probability is at the percent level. Finally, we discuss several mechanisms (including the curvaton and the inhomogeneous reheating) to investigate whether an initial statistically inhomogeneous isocurvature field fluctuation might give rise to some of the observed anomalies. In particular, we focus on the Cold Spot, the power deficit at low multipoles and the breaking of statistical isotropy.

  11. The natural approach to osteoporosis

    PubMed Central

    Bartolozzi, Emanuela

    2015-01-01

    Summary Osteoporosis is normally the result of a wrong life-style (diet, physical inactivity, smoke, dental hygiene, intestinal dysbiosis,…) and environmental toxicity which stimulate the chronic expression of inflammatory genes and alter the immuno-endocrine balance. A natural approch should face all the factors involved, leading the patients to become aware of their own responsability, and helping them with natural therapies, healthy food and life-style which support their body in the process of self-healing. PMID:26604935

  12. Natural Approaches to Reading and Writing.

    ERIC Educational Resources Information Center

    Antonacci, Patricia; Hedley, Carolyn

    Based on a two-day presentation workshop on early reading and writing approaches, the 12 essays in this book discuss the development of literacy, natural approaches in developing literacy, and supporting literacy development. Essays in the book are: (1) "Theories of Natural Language" (Carolyn N. Hedley); (2) "Oral Language…

  13. Anisotropies in the cosmic microwave background: an analytic approach

    NASA Astrophysics Data System (ADS)

    Hu, Wayne; Sugiyama, Naoshi

    1995-05-01

    We introduce a conceptually simple yet powerful analytic method which traces the structure of cosmic microwave background anisotropies to better than 5%-10% in temperature fluctuations on all scales. It is applicable to any model in which the gravitational potential is known and last scattering is sufficiently early. Moreover, it recovers and explains the presence of the 'Doppler peaks' at degree scales as driven acoustic oscillations of the photon-baryon fluid. We treat in detail such subtleties as the time dependence of the gravitational driving force, anisotropic stress from the neutrino quadrupole, and damping during the recombination process, again all from an analytic standpoint. We apply this formalism to the standard cold dark matter model to gain physical insight into the anisotropies, including the dependence of the peak locations and heights on cosmological parameters such as Omegab and h. Furthermore, the ionization history controls damping due to the finite thickness of the last scattering surface, which is in fact mianly caused by photon diffusion. In addition to being a powerful probe into the nature of anisotropies, this treatment can be used in place of the standard Boltzmann code where 5%-10% accuracy in temperature fluctuations is satisfactory and/or speed is essential. Equally importantly, it can be used as a portable standard by which numerical codes can be tested and compared.

  14. Enumerating viruses by using fluorescence and the nature of the nonviral background fraction.

    PubMed

    Pollard, Peter C

    2012-09-01

    Bulk fluorescence measurements could be a faster and cheaper way of enumerating viruses than epifluorescence microscopy, flow cytometry, or transmission electron microscopy (TEM). However, since viruses are not imaged, the background fluorescence compromises the signal, and we know little about its nature. In this paper the size ranges of nucleotides that fluoresce in the presence of SYBR gold were determined for wastewater and a range of freshwater samples using a differential filtration method. Fluorescence excitation-emission matrices (FEEMs) showed that >70% of the SYBR fluorescence was in the <10-nm size fraction (background) and was not associated with intact viruses. This was confirmed using TEM. The use of FEEMs to develop a fluorescence-based method for counting viruses is an approach that is fundamentally different from the epifluorescence microscopy technique used for enumerating viruses. This high fluorescence background is currently overlooked, yet it has had a most pervasive influence on the development of a simple fluorescence-based method for quantifying viral abundance in water.

  15. Geostatistics as a tool to improve the natural background level definition: An application in groundwater.

    PubMed

    Dalla Libera, Nico; Fabbri, Paolo; Mason, Leonardo; Piccinini, Leonardo; Pola, Marco

    2017-11-15

    The Natural Background Level (NBL), suggested by UE BRIDGE project, is suited for spatially distributed datasets providing a regional value that could be higher than the Threshold Value (TV) set by every country. In hydro-geochemically dis-homogeneous areas, the use of a unique regional NBL, higher than TV, could arise problems to distinguish between natural occurrences and anthropogenic contaminant sources. Hence, the goal of this study is to improve the NBL definition employing a geostatistical approach, which reconstructs the contaminant spatial structure accounting geochemical and hydrogeological relationships. This integrated mapping is fundamental to evaluate the contaminant's distribution impact on the NBL, giving indications to improve it. We decided to test this method on the Drainage Basin of Venice Lagoon (DBVL, NE Italy), where the existing NBL is seven times higher than the TV. This area is notoriously affected by naturally occurring arsenic contamination. An available geochemical dataset collected by 50 piezometers was used to reconstruct the spatial distribution of arsenic in the densely populated area of the DBVL. A cokriging approach was applied exploiting the geochemical relationships among As, Fe and NH4+. The obtained spatial predictions of arsenic concentrations were divided into three different zones: i) areas with an As concentration lower than the TV, ii) areas with an As concentration between the TV and the median of the values higher than the TV, and iii) areas with an As concentration higher than the median. Following the BRIDGE suggestions, where enough samples were available, the 90th percentile for each zone was calculated to obtain a local NBL (LNBL). Differently from the original NBL, this local value gives more detailed water quality information accounting the hydrogeological and geochemical setting, and contaminant spatial variation. Hence, the LNBL could give more indications about the distinction between natural occurrence and

  16. Pixel detectors in double beta decay experiments, a new approach for background reduction

    SciTech Connect

    Jose, J. M.; Čermák, P.; Štekl, I.; Rukhadze, E. N.; Rukhadze, N. I.; Brudanin, V. B.; Fiederle, M.; Fauler, A.; Loaiza, P.

    2013-08-08

    Double beta decay (ββ) experiments are challenging frontiers in contemporary physics. These experiments have the potential to investigate more about neutrinos (eg. nature and mass). The main challenge for these experiments is the reduction of background. The group at IEAP, CTU in Prague is investigating a new approach using pixel detectors Timepix. Pixel detector offer background reduction capabilities with its ability to identify the particle interaction (from the 2D signature it generates). However, use of pixel detectors has some challenges such as the presence of readout electronics near the sensing medium and heat dissipation. Different aspects of pixel setup (identification of radio-impurities, selection of radio-pure materials) and proposed experimental setup are presented. Also, results of preliminary background measurements (performed on the surface and in the underground laboratories) using the prototype setups are presented.

  17. Anisotropies of gravitational wave backgrounds: A line of sight approach

    NASA Astrophysics Data System (ADS)

    Contaldi, Carlo R.

    2017-08-01

    In the weak field regime, gravitational waves can be considered as being made up of collisionless, relativistic tensor modes that travel along null geodesics of the perturbed background metric. We work in this geometric optics picture to calculate the anisotropies in gravitational wave backgrounds resulting from astrophysical and cosmological sources. Our formalism yields expressions for the angular power spectrum of the anisotropies. We show how the anisotropies are sourced by intrinsic, Doppler, Sachs-Wolfe, and Integrated Sachs-Wolfe terms in analogy with Cosmic Microwave Background photons.

  18. Adaptive log-quadratic approach for target detection in nonhomogeneous backgrounds perturbed with speckle fluctuations.

    PubMed

    Magraner, Eric; Bertaux, Nicolas; Réfrégier, Philippe

    2008-12-01

    An approach for point target detection in the presence of speckle fluctuations with nonhomogeneous backgrounds is proposed. This approach is based on an automatic selection between the standard constant background model and a quadratic model for the logarithm of the background values. An improvement of the regulation of the false alarm probability in nonhomogeneous backgrounds is demonstrated.

  19. Human Blood Typing: A Forensic Science Approach. Part I: Background.

    ERIC Educational Resources Information Center

    Kobilinsky, Lawrence; Sheehan, Francis X.

    1988-01-01

    In this article, part I of a series, the forensic methods used in "typing" human blood, which as physical evidence is often found in the dried state, are outlined. Background information about individualization, antibody typing, fresh blood, dried blood, and additional systems is provided. (CW)

  20. A Novel Approach to Deepen Understanding of Undergraduates' Environmental Backgrounds

    ERIC Educational Resources Information Center

    Hvenegaard, Glen

    2007-01-01

    Universities often lack a detailed understanding of the environmental backgrounds of their students. One way to improve understanding is through segmentation, which breaks down a population into groups of people with similar characteristics. This study aims to use segmentation to determine groups within the student population, based on…

  1. Human Blood Typing: A Forensic Science Approach. Part I: Background.

    ERIC Educational Resources Information Center

    Kobilinsky, Lawrence; Sheehan, Francis X.

    1988-01-01

    In this article, part I of a series, the forensic methods used in "typing" human blood, which as physical evidence is often found in the dried state, are outlined. Background information about individualization, antibody typing, fresh blood, dried blood, and additional systems is provided. (CW)

  2. Natural background concentrations of nutrients in streams and rivers of the conterminous United States

    USGS Publications Warehouse

    Smith, R.A.; Alexander, R.B.; Schwarz, G.E.

    2003-01-01

    Determining natural background concentrations of nutrients in watersheds in the developed world has been hampered by a lack of pristine sampling sites covering a range of climatic conditions and basin sizes. Using data from 63 minimally impacted U.S. Geological Survey reference basins, we developed empirical models of the background yield of total nitrogen (TN) and total phosphorus (TP) from small watersheds as functions of annual runoff, basin size, atmospheric nitrogen deposition rate, and region-specific factors. We applied previously estimated in-stream loss rates to yields from the small watershed models to obtain estimates of background TN and TP yield and concentration throughout the stream/river network in 14 ecoregions of the conterminous United States. Background TN concentration varies from less than 0.02 mg L-1 in the xeric west to more than 0.5 mg L-1 along the southeastern coastal plain. Background TP concentration varies from less than 0.006 mg L-1 in the xeric west to more than 0.08 mg L-1 in the great plains. TN concentrations in U.S. streams and rivers currently exceed natural background levels by a much larger factor (6.4) than do TP concentrations (2.0). Because of local variation in runoff and other factors, the range of background nutrient concentrations is very large within some nutrient ecoregions. It is likely that background concentrations in some streams in these regions exceed proposed nutrient criteria.

  3. Computational Assessment of Naturally Occurring Neutron and Photon Background Radiation Produced by Extraterrestrial Sources

    SciTech Connect

    Miller, Thomas Martin; de Wet, Wouter C.; Patton, Bruce W.

    2015-10-28

    In this study, a computational assessment of the variation in terrestrial neutron and photon background from extraterrestrial sources is presented. The motivation of this assessment is to evaluate the practicality of developing a tool or database to estimate background in real time (or near–real time) during an experimental measurement or to even predict the background for future measurements. The extraterrestrial source focused on during this assessment is naturally occurring galactic cosmic rays (GCRs). The MCNP6 transport code was used to perform the computational assessment. However, the GCR source available in MCNP6 was not used. Rather, models developed and maintained by NASA were used to generate the GCR sources. The largest variation in both neutron and photon background spectra was found to be caused by changes in elevation on Earth's surface, which can be as large as an order of magnitude. All other perturbations produced background variations on the order of a factor of 3 or less. The most interesting finding was that ~80% and 50% of terrestrial background neutrons and photons, respectively, are generated by interactions in Earth's surface and other naturally occurring and man-made objects near a detector of particles from extraterrestrial sources and their progeny created in Earth's atmosphere. In conclusion, this assessment shows that it will be difficult to estimate the terrestrial background from extraterrestrial sources without a good understanding of a detector's surroundings. Therefore, estimating or predicting background during a measurement environment like a mobile random search will be difficult.

  4. Cancer Mortality Among People Living in Areas With Various Levels of Natural Background Radiation.

    PubMed

    Dobrzyński, Ludwik; Fornalski, Krzysztof W; Feinendegen, Ludwig E

    2015-01-01

    There are many places on the earth, where natural background radiation exposures are elevated significantly above about 2.5 mSv/year. The studies of health effects on populations living in such places are crucially important for understanding the impact of low doses of ionizing radiation. This article critically reviews some recent representative literature that addresses the likelihood of radiation-induced cancer and early childhood death in regions with high natural background radiation. The comparative and Bayesian analysis of the published data shows that the linear no-threshold hypothesis does not likely explain the results of these recent studies, whereas they favor the model of threshold or hormesis. Neither cancers nor early childhood deaths positively correlate with dose rates in regions with elevated natural background radiation.

  5. Cancer Mortality Among People Living in Areas With Various Levels of Natural Background Radiation

    PubMed Central

    Fornalski, Krzysztof W.; Feinendegen, Ludwig E.

    2015-01-01

    There are many places on the earth, where natural background radiation exposures are elevated significantly above about 2.5 mSv/year. The studies of health effects on populations living in such places are crucially important for understanding the impact of low doses of ionizing radiation. This article critically reviews some recent representative literature that addresses the likelihood of radiation-induced cancer and early childhood death in regions with high natural background radiation. The comparative and Bayesian analysis of the published data shows that the linear no-threshold hypothesis does not likely explain the results of these recent studies, whereas they favor the model of threshold or hormesis. Neither cancers nor early childhood deaths positively correlate with dose rates in regions with elevated natural background radiation. PMID:26674931

  6. An efficient background modeling approach based on vehicle detection

    NASA Astrophysics Data System (ADS)

    Wang, Jia-yan; Song, Li-mei; Xi, Jiang-tao; Guo, Qing-hua

    2015-10-01

    The existing Gaussian Mixture Model(GMM) which is widely used in vehicle detection suffers inefficiency in detecting foreground image during the model phase, because it needs quite a long time to blend the shadows in the background. In order to overcome this problem, an improved method is proposed in this paper. First of all, each frame is divided into several areas(A, B, C and D), Where area A, B, C and D are decided by the frequency and the scale of the vehicle access. For each area, different new learning rate including weight, mean and variance is applied to accelerate the elimination of shadows. At the same time, the measure of adaptive change for Gaussian distribution is taken to decrease the total number of distributions and save memory space effectively. With this method, different threshold value and different number of Gaussian distribution are adopted for different areas. The results show that the speed of learning and the accuracy of the model using our proposed algorithm surpass the traditional GMM. Probably to the 50th frame, interference with the vehicle has been eliminated basically, and the model number only 35% to 43% of the standard, the processing speed for every frame approximately has a 20% increase than the standard. The proposed algorithm has good performance in terms of elimination of shadow and processing speed for vehicle detection, it can promote the development of intelligent transportation, which is very meaningful to the other Background modeling methods.

  7. Training Teachers in the Natural Approach.

    ERIC Educational Resources Information Center

    Foreman, Mary Margaret

    This report describes the use of the natural approach to second language instruction to improve the teacher training program at Purdue University (Indiana). First, the report discusses the establishment of a permanent, non-tenure-track position of Assistant Director for Beginning Levels of Spanish. Second, focus is on the improvement of the…

  8. Hydrogeochemical characterization and Natural Background Levels in urbanized areas: Milan Metropolitan area (Northern Italy)

    NASA Astrophysics Data System (ADS)

    De Caro, Mattia; Crosta, Giovanni B.; Frattini, Paolo

    2017-04-01

    Although aquifers in densely populated and industrialized areas are extremely valuable and sensitive to contamination, an estimate of the groundwater quality status relative to baseline conditions is lacking for many of them. This paper provides a hydrogeochemical characterization of the groundwater in the Milan metropolitan area, one of the most densely populated areas in Europe. First, a conceptual model of the study area based on the analysis of the spatial distribution of natural chemical species and indicator contaminants is presented. The hydrochemical facies of the study area depend on the lithology of catchments drained by the main contributing rivers and on the aquifer settings. The anthropogenic influence on the groundwater quality of superficial aquifers is studied by means of probability plots, concentration versus depth plots and spatial-temporal plots for nitrate, sulfate and chloride. These allow differentiation of contaminated superficial aquifers from deep confined aquifers with baseline water quality. Natural Background Levels (NBL) of selected species (Cl, Na, NH4, SO4, NO3, As, Fe, Mn and Zn) are estimated by means of the pre-selection (PS) and the component separation (CS) statistical approaches. The NBLs depend on hydrogeological settings of the study area; sodium, chloride, sulfate and zinc NBL values never exceed the environmental water quality standards. NBL values of ammonium, iron, arsenic and manganese exceed the environmental water quality standards in the anaerobic portion of the aquifers. On the basis of observations, a set of criteria and precautions are suggested for adoption with both PS and CS methods in the aquifer characterization of highly urbanized areas.

  9. Geochemistry, biota and natural background levels in an arsenic naturally contaminated volcanic aquifer

    NASA Astrophysics Data System (ADS)

    Preziosi, Elisabetta; Amalfitano, Stefano; Di Lorenzo, Tiziana; Parrone, Daniele; Rossi, David; Ghergo, Stefano; Lungarini, Silvia; Zoppini, Anna Maria

    2015-04-01

    The tight links between chemical and ecological status are largely acknowledged as for surface water bodies, while aquifers are still considered as hidden groundwater reservoirs, rather than ecosystems to be preserved. Geochemical and biological interactions play a key role in all subterranean processes, including the dynamics of the fate of anthropogenic contaminants. Studies on groundwater dependent ecosystems (GDE) were mainly focused on karst aquifers so far, but an increased awareness on the importance of water-rock interactions and methodological improvements in microbial ecology are rapidly increasing the level of characterization of groundwater ecosystems in various hydrogeological contexts. Similarly, knowledge about groundwater biodiversity is still limited, especially if porous habitats are concerned. Yet, groundwater and GDEs are populated by a diverse and highly adapted biota, dominated by crustaceans, which provide important ecosystem services and act as biological indicators of chemical and quantitative impact on groundwater resources. In a previous research (Amalfitano et al. 2014), we reported that the microbial community heterogeneity may reflect the lithological and hydrogeological complexity within volcanic and alluvial facies transition in a groundwater body. The quantitative tracking of the microbial community structure allowed disentangling the natural biogeochemical processes evolving within the aquifer flow path. The analyses of groundwater crustaceans assemblages may contribute to shed more light upon the state and dynamics of such ecosystems. In the present research, a comprehensive study of a water table aquifer flowing through a quaternary volcanic district is being performed, including the geochemical (inorganic) composition, the microbial composition, and the analysis of crustacean assemblages . Groundwater samples are periodically collected from private wells and springs under a low anthropic impact. The key issues within the

  10. The PI3K Pathway: Background and Treatment Approaches.

    PubMed

    Lux, Michael P; Fasching, Peter A; Schrauder, Michael G; Hein, Alexander; Jud, Sebastian M; Rauh, Claudia; Beckmann, Matthias W

    2016-12-01

    Two-thirds of all breast cancer patients with metastases have a hormone receptor (HR)-positive/human epidermal growth factor receptor 2 (HER2)-negative subtype. Endocrine therapy is the treatment of choice in these patients since in addition to its effectiveness it can also maintain the patients' quality of life over a longer term. However, 44-62% of postmenopausal patients with metastatic breast carcinoma have primary tamoxifen resistance. After 3-5 years, 30-40% of the patients receiving tamoxifen treatment develop secondary resistance. Understanding the way in which resistance develops is therefore essential for developing treatment approaches that can prevent or reverse endocrine resistance. The phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling pathway plays a central role here. As a result of the numerous interactions involved, complex issues arise that need to be taken into account in the development and use of therapeutic agents. In addition, this signaling pathway is the one that most frequently undergoes mutations in breast cancer. The prognostic and predictive significance of individual mutations has not yet been fully explained, but it might provide a basis for patient selection in clinical studies. Initial research results on the use of PI3K inhibitors suggest that this may be a highly promising therapeutic approach, with an acceptable side effect profile.

  11. Natural background concentrations and threshold values of chemical species for groundwater in Korea

    NASA Astrophysics Data System (ADS)

    Hyun, Y.; Lee, S.; Lee, H.

    2014-12-01

    We analyze natural background concentrations and determine threshold values of chemical species (NO3-N, Cl, As, Pb, Cr) for groundwater using Groundwater Quality Monitoring Network (GQMN) data operated by Korea Ministry of Environment (ME). GQMN data are divided into two groups, A and B. Group A consists of samples collected in aquifers where anthropogenic inputs are forced to be excluded by aquifer typology. Group B consists of samples in aquifers where purely anthropogenic chemicals (e.g., pesticide, PAC) are introduced at the downgradient. Group A is used to derive nationwide natural background concentrations for groundwater in specific aquifer geology under concern, which represents a reference system. Group B is used for deriving site-specific background concentrations for groundwater. For both groups of data, the samples with anthropogenic inputs are forced to be excluded, thus background concentrations are derived based on a pre-selection method accordingly. We determine threshold values according to EU GroundWater Daughter Directive(GWDD 2006/11/EC). For As, Pb, and Cr and some other trace elements, survival analyses are used for estimating background concentrations due to non-detect data. The results show that high concentration values of NO3-N and Cr are related to high natural background concentrations due to rock-water interactions for Group A. In particular, NO3-N concentrations vary with depth, which are consistent with natural attenuation processes. For Group B, some anthropogenic chemical species such as BTEX are observed and site-specific background concentrations of those elements are non-zero, which is apparently not naturally occurred at all. Natural background concentrations and threshold values derived from Group A can be used for setting up reference values for managing groundwater quality on a level of either domestic or drinking water stands. Meanwhile results from Group B provide a useful guidance for managing groundwater quality in

  12. Genomic Approaches with Natural Fish Populations

    PubMed Central

    Oleksiak, M. F.

    2011-01-01

    Natural populations versus inbred stocks provide a much richer resource for identifying the effects of nucleotide substitutions because natural populations have greater polymorphism. Additionally, natural populations offer an advantage over most common research organisms because they are subject to natural selection, and analyses of these adaptations can be used to identify biologically important changes. Among fishes, these analyses are enhanced by having a wide diversity of species (> 28,000 species, more than any other group of vertebrates) living in a huge range of environments (from below freezing to > 46° C, in fresh water to salinities > 40 ppt.). Moreover, fishes exhibit many different life history and reproductive strategies and have many different phenotypes and social structures. While fishes provide numerous advantages over other vertebrate models, there is still a dearth of available genomic tools for fishes. Fish make up approximately half of all known vertebrate species, yet less than 0.2% of fish species have significant genomic resources. Nonetheless, genomic approaches with fishes have provided some of the first measures of individual variation in gene expression and insights in to environmental and ecological adaptations. Thus, genomic approaches with natural fish populations have the potential to revolutionize fundamental studies of diverse fish species that offer myriad ecological and evolutionary questions. PMID:20409163

  13. Neurochemical background and approaches in the understanding of motion sickness

    NASA Technical Reports Server (NTRS)

    Kohl, R. L.

    1982-01-01

    The problems and nature of space motion sickness were defined. The neurochemical and neurophysiological bases of vestibular system function and of the expression of motion sickness wre reviewed. Emphasis was given to the elucidation of the neuropharmacological mechanisms underlying the effects of scopolamine and amphetamine on motion sickness. Characterization of the ascending reticular activating system and the limbic system provided clues to the etiology of the side effects of scopolamine. The interrelationship between central cholinergic pathways and the peripheral (autonomic) expression of motion sickness was described. A correlation between the stress of excessive motion and a variety of hormonal responses to that stress was also detailed. The cholinergic system is involved in the efferent modulation of the vestibular hair cells, as an afferent modulator of the vestibular nuclei, in the activation of cortical and limbic structures, in the expression of motion sickness symptoms and most likely underscores a number of the hormonal changes that occur in stressful motion environments. The role of lecithin in the regulation of the levels of neurotransmitters was characterized as a possible means by which cholinergic neurochemistry can be modulated.

  14. General background and approach to multibody dynamics for space applications

    NASA Astrophysics Data System (ADS)

    Santini, Paolo; Gasbarri, Paolo

    2009-06-01

    Multibody dynamics for space applications is dictated by space environment such as space-varying gravity forces, orbital and attitude perturbations, control forces if any. Several methods and formulations devoted to the modeling of flexible bodies undergoing large overall motions were developed in recent years. Most of these different formulations were aimed to face one of the main problems concerning the analysis of spacecraft dynamics namely the reduction of computer simulation time. By virtue of this, the use of symbolic manipulation, recursive formulation and parallel processing algorithms were proposed. All these approaches fall into two categories, the one based on Newton/Euler methods and the one based on Lagrangian methods; both of them have their advantages and disadvantages although in general, Newtonian approaches lend to a better understanding of the physics of problems and in particular of the magnitude of the reactions and of the corresponding structural stresses. Another important issue which must be addressed carefully in multibody space dynamics is relevant to a correct choice of kinematics variables. In fact, when dealing with flexible multibody system the resulting equations include two different types of state variables, the ones associated with large (rigid) displacements and the ones associated with elastic deformations. These two sets of variables have generally two different time scales if we think of the attitude motion of a satellite whose period of oscillation, due to the gravity gradient effects, is of the same order of magnitude as the orbital period, which is much bigger than the one associated with the structural vibration of the satellite itself. Therefore, the numerical integration of the equations of the system represents a challenging problem. This was the abstract and some of the arguments that Professor Paolo Santini intended to present for the Breakwell Lecture; unfortunately a deadly disease attacked him and shortly took him

  15. Severe antenatally diagnosed renal disorders: background, prognosis and practical approach.

    PubMed

    Aulbert, Wiebke; Kemper, Markus J

    2016-04-01

    Nowadays most renal disorders, especially urinary tract malformations and renal cystic disease, are diagnosed antenatally. In cases of severe bilateral disease, intrauterine renal dysfunction may lead to renal oligohydramnios (ROH), resulting in pulmonary hypoplasia which affects perinatal mortality and morbidity as well as the long-term outcome. However, some infants may only have mild pulmonary and renal disease, and advances in postnatal and dialysis treatment have resulted in improved short- and long-term outcome even in those infants with severe ROH. Here, we review the current state of knowledge and clinical experience of patients presenting antenatally with severe bilateral renal disorders and ROH. By addressing underlying mechanisms, intrauterine tools of diagnosis and treatment as well as published outcome data, we hope to improve antenatal counselling and postnatal care. KEY SUMMARY POINTS: 1. Nowadays most renal disorders are diagnosed antenatally, especially urinary tract malformations and renal cystic disease. 2. Severe kidney dysfunction may lead to renal oligohydramnios, which can cause pulmonary hypoplasia and is a risk factor of perinatal mortality and postnatal renal outcome. However, as considerable clinical heterogeneity is present, outcome predictions need to be treated with caution. 3. Advances in postnatal and dialysis treatment have resulted in improved short- and long-term outcomes even in infants with severe renal oligohydramnios. 4. A multidisciplinary approach with specialist input is required when counselling a family with an ROH-affected fetus as the decision-making process is very challenging.

  16. Computational Assessment of Naturally Occurring Neutron and Photon Background Radiation Produced by Extraterrestrial Sources

    DOE PAGES

    Miller, Thomas Martin; de Wet, Wouter C.; Patton, Bruce W.

    2015-10-28

    In this study, a computational assessment of the variation in terrestrial neutron and photon background from extraterrestrial sources is presented. The motivation of this assessment is to evaluate the practicality of developing a tool or database to estimate background in real time (or near–real time) during an experimental measurement or to even predict the background for future measurements. The extraterrestrial source focused on during this assessment is naturally occurring galactic cosmic rays (GCRs). The MCNP6 transport code was used to perform the computational assessment. However, the GCR source available in MCNP6 was not used. Rather, models developed and maintained bymore » NASA were used to generate the GCR sources. The largest variation in both neutron and photon background spectra was found to be caused by changes in elevation on Earth's surface, which can be as large as an order of magnitude. All other perturbations produced background variations on the order of a factor of 3 or less. The most interesting finding was that ~80% and 50% of terrestrial background neutrons and photons, respectively, are generated by interactions in Earth's surface and other naturally occurring and man-made objects near a detector of particles from extraterrestrial sources and their progeny created in Earth's atmosphere. In conclusion, this assessment shows that it will be difficult to estimate the terrestrial background from extraterrestrial sources without a good understanding of a detector's surroundings. Therefore, estimating or predicting background during a measurement environment like a mobile random search will be difficult.« less

  17. Knowledge engineering approach to natural language understanding

    SciTech Connect

    Shapiro, S.C.; Neal, J.G.

    1982-01-01

    The authors describe the results of a preliminary study of a knowledge engineering approach to natural language understanding. A computer system is being developed to handle the acquisition, representation, and use of linguistic knowledge. The computer system is rule-based and utilizes a semantic network for knowledge storage and representation. In order to facilitate the interaction between user and system, input of linguistic knowledge and computer responses are in natural language. Knowledge of various types can be entered and utilized: syntactic and semantic; assertions and rules. The inference tracing facility is also being developed as a part of the rule-based system with output in natural language. A detailed example is presented to illustrate the current capabilities and features of the system. 12 references.

  18. Assessing Natural Background Levels of aquifers in the Metropolitan Area of Milan (Lombardy)

    NASA Astrophysics Data System (ADS)

    De Caro, Mattia; Crosta, Giovanni; Frattini, Paolo

    2016-04-01

    The European Water Framework Directive (WFD 2000/60/CE) requires Member States to evaluate the status of groundwater bodies in order to reach a good water quality for human consumption. One of the preliminary steps for defining the status of groundwater bodies consists in the definition and evaluation of the so-called Natural Background Levels (NBL). The NBL or Baseline level can be defined as "the range of concentration of a given element, isotope or chemical compound in solution, derived entirely from natural, geological, biological or atmospheric sources, under conditions not perturbed by anthropogenic activity" (Edmund and Shand, 2009). The qualitative analysis for a large area (ca 4500 Km2) of the Po Plain around the Milan Metropolitan area (Lombardy, Italy) is presented in this study. Despite the aquifers in the Milan metropolitan area are an incredible groundwater resource for a very large population (3.195.629 inhabitants in the metropolitan area, data at November 2014) and a highly industrialized area, a groundwater baseline characterization is still missing. In order to attain the hydro-geochemical characterization a complete geodatabase was built (120.655 chemical samples from 1980 to 2014). This database has been explored by classical and multivariate statistical analyses to provide relationships among the more influential lithological, hydrogeological and hydro-chemical variables. Finally, the NBLs of different chemical species which may be anthropogenic sensitive (Na, Cl, K, NO3, SO4, NH4, As, Fe, Cr, Fe, Mn, Zn) and for multiple aquifer bodies (phreatic, semi-confined and confined aquifer) are evaluated. Two different approaches are applied: the Pre-Selection method (BRIDGE, 2006) and the Component-Separation method. The first one (PS) consists in the exclusion of samples from the available dataset that could indicate human activities then deriving the NBL as the 90th percentile of the remaining data. The second one (CS) consists in the fitting of

  19. Synthetic Biological Approaches to Natural Product Biosynthesis

    PubMed Central

    Winter, Jaclyn M; Tang, Yi

    2012-01-01

    Small molecules produced in Nature continue to be an inspiration for the development of new therapeutic agents. These natural products possess exquisite chemical diversity, which gives rise to their wide range of biological activities. In their host organism, natural products are assembled and modified by dedicated biosynthetic pathways that Nature has meticulously developed. Often times, the complex structures or chemical modifications instated by these pathways are difficult to replicate using traditional synthetic methods. An alternative approach for creating or enhancing the structural variation of natural products is through combinatorial biosynthesis. By rationally reprogramming and manipulating the biosynthetic machinery responsible for their production, unnatural metabolites that were otherwise inaccessible can be obtained. Additionally, new chemical structures can be synthesized or derivatized by developing the enzymes that carry out these complicated chemical reactions into biocatalysts. In this review, we will discuss a variety of combinatorial biosynthetic strategies, their technical challenges, and highlight some recent (since 2007) examples of rationally designed unnatural metabolites, as well as platforms that have been established for the production and modification of clinically important pharmaceutical compounds. PMID:22221832

  20. Modeling the Effects of Atmospheric Propagation for Spectral Libraries of Natural Backgrounds

    DTIC Science & Technology

    2007-10-01

    Laboratory, 244 Wood Street, Lexington, MA 02420 dNational Air and Space Intelligence Center, 4180 Watson Way, Wright Patterson AFB, OH 45433 ’Air...Visible and Infrared Imaging Spectrometer (AVIRIS) hyperspectral datacube collected over Fort AP Hill, VA, were used to demonstrate the effects of the...transmission/compensation doublet on the spectral variability of natural backgrounds. Specifically, statistics derived from Airborne Visible and Infrared

  1. natural background radiation dosimetry in the highest altitude region of Iran.

    PubMed

    Shahbazi-Gahrouei, Daryoush

    2003-09-01

    The natural background radiation has been measured in one of the highest altitude regions (Zagros Mountains), Chaharmahal and Bakhtiari province, in the south west of Iran. The outdoors-environmental monitoring exposure rate of radiation was measured in 200 randomly chosen regions using portable Geiger-Muller and scintillation detectors. Eight measurements were made in each region and an average value was used to calculate the exposure rate from natural background radiation. The average exposure rate was found to be 0.246 microGy/h and the annual average effective dose equivalent was found to be 0.49 mSv. An overall population-weighted mean outdoor dose rate was calculated to be 49 nGy/h, which is higher than the world-wide mean value of 44 nGy/h, as reported by UNSCEAR in 1998, and is comparable to the annual effective dose equivalent of 0.38 mSv. A good correlation between the altitude and the exposure rate was observed, as the higher altitude regions have higher natural background radiation levels.

  2. Background in the context of land contaminated with naturally occurring radioactive material.

    PubMed

    Read, D; Read, G D; Thorne, M C

    2013-06-01

    The financial implications of choosing a particular threshold for clearance of radioactively contaminated land are substantial, particularly when one considers the volume of naturally occurring radioactive material (NORM) created each year by the production and combustion of fossil fuels and the exploitation of industrial minerals. Inevitably, a compromise needs to be reached between the level of environmental protection sought and the finite resources available for remediation. In the case of natural series radionuclides, any anthropogenic input is always superimposed on the inventory already present in the soil; this 'background' inventory is conventionally disregarded when assessing remediation targets. Unfortunately, the term is not well defined and the concept of 'background dose' is open to alternative interpretations. In this paper, we address the issue of natural background from a geochemical rather than from a solely radiological perspective, illustrating this with an example from the china clay industry. We propose a simple procedure for decision making based on activity concentrations of primordial radionuclides and their progeny. Subsequent calculations of dose need to take into account the mineralogical and chemical characteristics of the contamination, which in the case of NORM are invariably reflected in uranium series disequilibrium.

  3. Simulating the Impact of the Natural Radiation Background on Bacterial Systems: Implications for Very Low Radiation Biological Experiments.

    PubMed

    Lampe, Nathanael; Biron, David G; Brown, Jeremy M C; Incerti, Sébastien; Marin, Pierre; Maigne, Lydia; Sarramia, David; Seznec, Hervé; Breton, Vincent

    2016-01-01

    At very low radiation dose rates, the effects of energy depositions in cells by ionizing radiation is best understood stochastically, as ionizing particles deposit energy along tracks separated by distances often much larger than the size of cells. We present a thorough analysis of the stochastic impact of the natural radiative background on cells, focusing our attention on E. coli grown as part of a long term evolution experiment in both underground and surface laboratories. The chance per day that a particle track interacts with a cell in the surface laboratory was found to be 6 × 10-5 day-1, 100 times less than the expected daily mutation rate for E. coli under our experimental conditions. In order for the chance cells are hit to approach the mutation rate, a gamma background dose rate of 20 μGy hr-1 is predicted to be required.

  4. Simulating the Impact of the Natural Radiation Background on Bacterial Systems: Implications for Very Low Radiation Biological Experiments

    PubMed Central

    Lampe, Nathanael; Biron, David G.; Brown, Jeremy M. C.; Incerti, Sébastien; Marin, Pierre; Maigne, Lydia; Sarramia, David; Seznec, Hervé; Breton, Vincent

    2016-01-01

    At very low radiation dose rates, the effects of energy depositions in cells by ionizing radiation is best understood stochastically, as ionizing particles deposit energy along tracks separated by distances often much larger than the size of cells. We present a thorough analysis of the stochastic impact of the natural radiative background on cells, focusing our attention on E. coli grown as part of a long term evolution experiment in both underground and surface laboratories. The chance per day that a particle track interacts with a cell in the surface laboratory was found to be 6 × 10−5 day−1, 100 times less than the expected daily mutation rate for E. coli under our experimental conditions. In order for the chance cells are hit to approach the mutation rate, a gamma background dose rate of 20 μGy hr−1 is predicted to be required. PMID:27851794

  5. Object detection in natural backgrounds predicted by discrimination performance and models

    NASA Technical Reports Server (NTRS)

    Rohaly, A. M.; Ahumada, A. J. Jr; Watson, A. B.

    1997-01-01

    Many models of visual performance predict image discriminability, the visibility of the difference between a pair of images. We compared the ability of three image discrimination models to predict the detectability of objects embedded in natural backgrounds. The three models were: a multiple channel Cortex transform model with within-channel masking; a single channel contrast sensitivity filter model; and a digital image difference metric. Each model used a Minkowski distance metric (generalized vector magnitude) to summate absolute differences between the background and object plus background images. For each model, this summation was implemented with three different exponents: 2, 4 and infinity. In addition, each combination of model and summation exponent was implemented with and without a simple contrast gain factor. The model outputs were compared to measures of object detectability obtained from 19 observers. Among the models without the contrast gain factor, the multiple channel model with a summation exponent of 4 performed best, predicting the pattern of observer d's with an RMS error of 2.3 dB. The contrast gain factor improved the predictions of all three models for all three exponents. With the factor, the best exponent was 4 for all three models, and their prediction errors were near 1 dB. These results demonstrate that image discrimination models can predict the relative detectability of objects in natural scenes.

  6. Object detection in natural backgrounds predicted by discrimination performance and models

    NASA Technical Reports Server (NTRS)

    Rohaly, A. M.; Ahumada, A. J. Jr; Watson, A. B.

    1997-01-01

    Many models of visual performance predict image discriminability, the visibility of the difference between a pair of images. We compared the ability of three image discrimination models to predict the detectability of objects embedded in natural backgrounds. The three models were: a multiple channel Cortex transform model with within-channel masking; a single channel contrast sensitivity filter model; and a digital image difference metric. Each model used a Minkowski distance metric (generalized vector magnitude) to summate absolute differences between the background and object plus background images. For each model, this summation was implemented with three different exponents: 2, 4 and infinity. In addition, each combination of model and summation exponent was implemented with and without a simple contrast gain factor. The model outputs were compared to measures of object detectability obtained from 19 observers. Among the models without the contrast gain factor, the multiple channel model with a summation exponent of 4 performed best, predicting the pattern of observer d's with an RMS error of 2.3 dB. The contrast gain factor improved the predictions of all three models for all three exponents. With the factor, the best exponent was 4 for all three models, and their prediction errors were near 1 dB. These results demonstrate that image discrimination models can predict the relative detectability of objects in natural scenes.

  7. Object Detection in Natural Backgrounds Predicted by Discrimination Performance and Models

    NASA Technical Reports Server (NTRS)

    Ahumada, A. J., Jr.; Watson, A. B.; Rohaly, A. M.; Null, Cynthia H. (Technical Monitor)

    1995-01-01

    In object detection, an observer looks for an object class member in a set of backgrounds. In discrimination, an observer tries to distinguish two images. Discrimination models predict the probability that an observer detects a difference between two images. We compare object detection and image discrimination with the same stimuli by: (1) making stimulus pairs of the same background with and without the target object and (2) either giving many consecutive trials with the same background (discrimination) or intermixing the stimuli (object detection). Six images of a vehicle in a natural setting were altered to remove the vehicle and mixed with the original image in various proportions. Detection observers rated the images for vehicle presence. Discrimination observers rated the images for any difference from the background image. Estimated detectabilities of the vehicles were found by maximizing the likelihood of a Thurstone category scaling model. The pattern of estimated detectabilities is similar for discrimination and object detection, and is accurately predicted by a Cortex Transform discrimination model. Predictions of a Contrast- Sensitivity- Function filter model and a Root-Mean-Square difference metric based on the digital image values are less accurate. The discrimination detectabilities averaged about twice those of object detection.

  8. Object Detection in Natural Backgrounds Predicted by Discrimination Performance and Models

    NASA Technical Reports Server (NTRS)

    Ahumada, A. J., Jr.; Watson, A. B.; Rohaly, A. M.; Null, Cynthia H. (Technical Monitor)

    1995-01-01

    In object detection, an observer looks for an object class member in a set of backgrounds. In discrimination, an observer tries to distinguish two images. Discrimination models predict the probability that an observer detects a difference between two images. We compare object detection and image discrimination with the same stimuli by: (1) making stimulus pairs of the same background with and without the target object and (2) either giving many consecutive trials with the same background (discrimination) or intermixing the stimuli (object detection). Six images of a vehicle in a natural setting were altered to remove the vehicle and mixed with the original image in various proportions. Detection observers rated the images for vehicle presence. Discrimination observers rated the images for any difference from the background image. Estimated detectabilities of the vehicles were found by maximizing the likelihood of a Thurstone category scaling model. The pattern of estimated detectabilities is similar for discrimination and object detection, and is accurately predicted by a Cortex Transform discrimination model. Predictions of a Contrast- Sensitivity- Function filter model and a Root-Mean-Square difference metric based on the digital image values are less accurate. The discrimination detectabilities averaged about twice those of object detection.

  9. Review of approaches to the recording of background lesions in toxicologic pathology studies in rats.

    PubMed

    McInnes, E F; Scudamore, C L

    2014-08-17

    Pathological evaluation of lesions caused directly by xenobiotic treatment must always take into account the recognition of background (incidental) findings. Background lesions can be congenital or hereditary, histological variations, changes related to trauma or normal aging and physiologic or hormonal changes. This review focuses on the importance and correct approach to recording of background changes and includes discussion on sources of variability in background changes, the correct use of terminology, the concept of thresholds, historical control data, diagnostic drift, blind reading of slides, scoring and artifacts. The review is illustrated with background lesions in Sprague Dawley and Wistar rats. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  10. Natural background dose and radium equivalent measurements at Ikogosi warm spring, Nigeria.

    PubMed

    Isinkaye, M O; Ajayi, I R

    2006-01-01

    The natural background dose and the radium equivalent due to the natural radioactivity levels in rocks and sediments collected around Ikogosi warm spring, Nigeria, has been determined in this study using a highly sensitive HpGe detector. The mean activity concentration of (40)K, (226)Ra and (228)Ac were measured to be 585.50 +/- 17.40 Bq kg(-1), 66.91 +/- 5.23 Bq kg(-1) and 48.91 +/- 2.10 Bq kg(-1), respectively, in rock samples while in sediment samples the activity concentrations were found to be 113.89 +/- 5.64 Bq kg(-1) for (40)K, 21.47 +/- 5.14 Bq kg(-1) for (226)Ra and 14.20 +/- 1.07 Bq kg(-1) for (228)Ac. This mean values give rise to average absorbed dose rate of 85.87 nGy h(-1) at a distance of 1.0 m above the ground level and a mean human effective dose equivalent of 0.53 man Sv y(-1) for rock samples. A radium equivalent of 50.55 Bq kg(-1) was measured for the sediment samples. The radium equivalent value is far less than the 370 Bq kg(-1) limit for materials that can be used as building materials while the human effective dose equivalent falls below the world average background dose of 2.4 man Sv y(-1).

  11. An automatic segmentation method for multi-tomatoes image under complicated natural background

    NASA Astrophysics Data System (ADS)

    Yin, Jianjun; Mao, Hanping; Hu, Yongguang; Wang, Xinzhong; Chen, Shuren

    2006-12-01

    It is a fundamental work to realize intelligent fruit-picking that mature fruits are distinguished from complicated backgrounds and determined their three-dimensional location. Various methods for fruit identification can be found from the literatures. However, surprisingly little attention has been paid to image segmentation of multi-fruits which growth states are separated, connected, overlapped and partially covered by branches and leaves of plant under the natural illumination condition. In this paper we present an automatic segmentation method that comprises of three main steps. Firstly, Red and Green component image are extracted from RGB color image, and Green component subtracted from Red component gives RG of chromatic aberration gray-level image. Gray-level value between objects and background has obviously difference in RG image. By the feature, Ostu's threshold method is applied to do adaptive RG image segmentation. And then, marker-controlled watershed segmentation based on morphological grayscale reconstruction is applied into Red component image to search boundary of connected or overlapped tomatoes. Finally, intersection operation is done by operation results of above two steps to get binary image of final segmentation. The tests show that the automatic segmentation method has satisfactory effect upon multi-tomatoes image of various growth states under the natural illumination condition. Meanwhile, it has very robust for different maturity of multi-tomatoes image.

  12. Natural inflation: consistency with cosmic microwave background observations of Planck and BICEP2

    SciTech Connect

    Freese, Katherine; Kinney, William H. E-mail: whkinney@buffalo.edu

    2015-03-01

    Natural inflation is a good fit to all cosmic microwave background (CMB) data and may be the correct description of an early inflationary expansion of the Universe. The large angular scale CMB polarization experiment BICEP2 has announced a major discovery, which can be explained as the gravitational wave signature of inflation, at a level that matches predictions by natural inflation models. The natural inflation (NI) potential is theoretically exceptionally well motivated in that it is naturally flat due to shift symmetries, and in the simplest version takes the form V(φ) = Λ{sup 4} [1 ± cos(Nφ/f)]. A tensor-to-scalar ratio r > 0.1 as seen by BICEP2 requires the height of any inflationary potential to be comparable to the scale of grand unification and the width to be comparable to the Planck scale. The Cosine Natural Inflation model agrees with all cosmic microwave background measurements as long as f ≥ m{sub Pl} (where m{sub Pl} = 1.22 × 10{sup 19} GeV) and Λ ∼ m{sub GUT} ∼ 10{sup 16} GeV. This paper also discusses other variants of the natural inflation scenario: we show that axion monodromy with potential V∝ φ{sup 2/3} is inconsistent with the BICEP2 limits at the 95% confidence level, and low-scale inflation is strongly ruled out. Linear potentials V ∝ φ are inconsistent with the BICEP2 limit at the 95% confidence level, but are marginally consistent with a joint Planck/BICEP2 limit at 95%. We discuss the pseudo-Nambu Goldstone model proposed by Kinney and Mahanthappa as a concrete realization of low-scale inflation. While the low-scale limit of the model is inconsistent with the data, the large-field limit of the model is marginally consistent with BICEP2. All of the models considered predict negligible running of the scalar spectral index, and would be ruled out by a detection of running.

  13. Disruptive camouflage tricks the human eye: a study of detection times of two near-similar targets in natural backgrounds

    NASA Astrophysics Data System (ADS)

    Selj, Gorm K.

    2015-10-01

    Our understanding of camouflage, in military as well as in evolutionary perspectives, has been developing over the last 100 years. In that period of time several underlying principles have emerged. It has turned out in the recent decade that background pattern matching alone may not be sufficient to conceal targets because of the ubiquitous and revealing information contained by the edges of a target. In this paper we have studied one concealment strategy, the so-called disruptive coloration, further as it predicts that high contrast patches placed at the target's outline will impede detection, by creating false target edges when exposed to the observer. Such disruptive coloration is contra-intuitive as it may impede detection in spite of the fact that the patches themselves may be poorly concealed. In military environments the "disruptive approach" within camouflage has been textbook material for decades. Still, very little has been reported, supporting this idea, especially when it comes to the concealment of human targets in natural sceneries. We report here experimental evidence from a field study, containing detection data from 12 unique natural scenes (5 testing the disruptive effect, 7 as reference tests), with both human targets and human observers, showing that disruptively colored camouflage patches along a human's outline (its head) may increase detection time significantly as when compared to a similar (human) target concealed only with background matching. Hence, our results support the idea that disruptive coloration may impede detection and similarly that the best concealment is achieved when disruptive coloration is added to a target that matches the background (reasonably) well. This study raises important question to the current understanding of human vision and concealment as well as to any approach to describe the human visual system mathematically.

  14. Trichloromethyl compounds--natural background concentrations and fates within and below coniferous forests.

    PubMed

    Albers, Christian Nyrop; Hansen, Poul Erik; Jacobsen, Ole Stig

    2010-11-15

    Pollution with organochlorines has received major attention due to various environmental effects, but it is now increasingly recognized, that they also take part in biogeochemical cycles and that natural background concentrations exist for several chlorinated compounds. We here report the natural occurrence and cycling of organic compounds with a trichloromethyl moiety in common. The study areas are temperate coniferous forests. Trichloromethyl compounds can be found in all compartments of the forests (groundwater, soil, vegetation and throughfall), but not all compounds in all compartments. The atmospheric input of trichloromethyl compounds is found to be minor, with significant contributions for trichloroacetic acid (TCAA), only. In top soil, where the formation of the compounds is expected to occur, there is a clear positive relationship between chloroform and trichloroacetyl containing compounds. Other positive relations occur, which in combination with chlorination experiments performed in the laboratory, point to the fact that all the trichloromethyl compounds may be formed concurrently in the soil, and their subsequent fates then differ due to different physical, chemical and biological properties. TCAA cannot be detected in soil and groundwater, but sorption and mineralization experiments performed in the laboratory in combination with analyses of vegetation, show that TCAA is probably formed in the top soil and then partly taken up by the vegetation and partly mineralized in the soil. Based on this and previous studies, a conceptual model for the natural cycling of trichloromethyl compounds in forests is proposed. Copyright © 2010 Elsevier B.V. All rights reserved.

  15. Technical note: An improved approach to determining background aerosol concentrations with PILS sampling on aircraft

    NASA Astrophysics Data System (ADS)

    Fukami, Christine S.; Sullivan, Amy P.; Ryan Fulgham, S.; Murschell, Trey; Borch, Thomas; Smith, James N.; Farmer, Delphine K.

    2016-07-01

    Particle-into-Liquid Samplers (PILS) have become a standard aerosol collection technique, and are widely used in both ground and aircraft measurements in conjunction with off-line ion chromatography (IC) measurements. Accurate and precise background samples are essential to account for gas-phase components not efficiently removed and any interference in the instrument lines, collection vials or off-line analysis procedures. For aircraft sampling with PILS, backgrounds are typically taken with in-line filters to remove particles prior to sample collection once or twice per flight with more numerous backgrounds taken on the ground. Here, we use data collected during the Front Range Air Pollution and Photochemistry Éxperiment (FRAPPÉ) to demonstrate that not only are multiple background filter samples are essential to attain a representative background, but that the chemical background signals do not follow the Gaussian statistics typically assumed. Instead, the background signals for all chemical components analyzed from 137 background samples (taken from ∼78 total sampling hours over 18 flights) follow a log-normal distribution, meaning that the typical approaches of averaging background samples and/or assuming a Gaussian distribution cause an over-estimation of background samples - and thus an underestimation of sample concentrations. Our approach of deriving backgrounds from the peak of the log-normal distribution results in detection limits of 0.25, 0.32, 3.9, 0.17, 0.75 and 0.57 μg m-3 for sub-micron aerosol nitrate (NO3-), nitrite (NO2-), ammonium (NH4+), sulfate (SO42-), potassium (K+) and calcium (Ca2+), respectively. The difference in backgrounds calculated from assuming a Gaussian distribution versus a log-normal distribution were most extreme for NH4+, resulting in a background that was 1.58× that determined from fitting a log-normal distribution.

  16. Natural 'background' soil water repellency in conifer forests: its prediction and relationship to wildfire occurrence

    NASA Astrophysics Data System (ADS)

    Doerr, Stefan; Woods, Scott; Martin, Deborah; Casimiro, Marta

    2013-04-01

    Soils under a wide range of vegetation types exhibit water repellency following the passage of a fire. This is viewed by many as one of the main causes for accelerated post-fire runoff and soil erosion and it has often been assumed that strong soil water repellency present after wildfire is fire-induced. However, high levels of repellency have also been reported under vegetation types not affected by fire, and the question arises to what degree the water repellency observed at burnt sites actually results from fire. This study aimed at determining 'natural background' water repellency in common coniferous forest types in the north-western USA. Mature or semi-mature coniferous forest sites (n = 81), which showed no evidence of recent fires and had at least some needle cast cover, were sampled across six states. After careful removal of litter and duff at each site, soil water repellency was examined in situ at the mineral soil surface using the Water Drop Penetration Time (WDPT) method for three sub-sites, followed by col- lecting near-surface mineral soil layer samples (0-3 cm depth). Following air-drying, samples were fur- ther analyzed for repellency using WDPT and contact angle (hsl) measurements. Amongst other variables examined were dominant tree type, ground vegetation, litter and duff layer depth, slope angle and aspect, elevation, geology, and soil texture, organic carbon content and pH. 'Natural background' water repellency (WDPT > 5 s) was detected in situ and on air-dry samples at 75% of all sites examined irrespective of dominant tree species (Pinus ponderosa, Pinus contorta, Picea engelma- nii and Pseudotsuga menziesii). These findings demonstrate that the soil water repellency commonly observed in these forest types following burning is not necessarily the result of recent fire but can instead be a natural characteristic. The notion of a low background water repellency being typical for long- unburnt conifer forest soils of the north-western USA is

  17. Particle in a self-dual dyon background: Hidden free nature and exotic superconformal symmetry

    NASA Astrophysics Data System (ADS)

    Plyushchay, Mikhail S.; Wipf, Andreas

    2014-02-01

    We show that a nonrelativistic particle in a combined field of a magnetic monopole and 1/r2 potential reveals a hidden, partially free dynamics when the strength of the central potential and the charge-monopole coupling constant are mutually fitted to each other. In this case the system admits both a conserved Laplace-Runge-Lenz vector and a dynamical conformal symmetry. The supersymmetrically extended system corresponds then to a background of a self-dual or anti-self-dual dyon. It is described by a quadratically extended Lie superalgebra D(2,1;α) with α=1/2, in which the bosonic set of generators is enlarged by a generalized Laplace-Runge-Lenz vector and its dynamical integral counterpart related to Galilei symmetry, as well as by the chiral Z2-grading operator. The odd part of the nonlinear superalgebra comprises a complete set of 24=2×3×4 fermionic generators. Here a usual duplication comes from the Z2-grading structure; the second factor can be associated with a triad of scalar integrals—the Hamiltonian, the generator of special conformal transformations, and the squared total angular momentum vector, while the quadruplication is generated by a chiral spin vector integral which exits due to the (anti-)self-dual nature of the electromagnetic background.

  18. The isotropic nature of the background turbulence spectra in the solar wind

    NASA Astrophysics Data System (ADS)

    Wang, X.; Tu, C. Y.; He, J.; Marsch, E.; Wang, L.

    2014-12-01

    At the high-frequency end of the inertial range, the solar wind turbulence power spectrum was recently found to be anisotropic with respect to the direction of local magnetic field, as an evidence for the presence of a "critical balance" style turbulence cascade. However, we find that the spectral anisotropy seems to result from intermittent structures. The following two independent studies corroborate this statement by showing that the power spectra of the background turbulence, in which there are no intermittent structures, have an isotropic nature. In Study 1, we remove the wavelet coefficients of the local intermittency with large partial variance increment (PVI), and find the spectral indices of the magnetic field are 1.63±0.02, independent of the angle θRB between the direction of the local background magnetic field and the radial direction. In Study 2, we make a statistical study on the magnetic field spectral indices obtained by using Fast Fourier Transform on 40 time series, in which no intermittent structures appear. We find that for the time series with 0o<θRB <6o, the probability distribution of the observed spectral indices peaks at -1.7, while the -2 index predicted by the "critical balance" theory rarely appears. For the time series with 84 o <θRB <90 o, the probability distribution of the indices peaks at -1.5. Considering the uncertainty of the statistics, these results show that the background-turbulence spectra are nearly isotropic with respect to θRB, which may be consistent with some explanations based on hydrodynamic turbulence theory.

  19. Dual approach for automated sleep spindles detection within EEG background activity in infant polysomnograms.

    PubMed

    Held, Claudio M; Causa, Leonardo; Estévez, Pablo; Pérez, Claudio; Garrido, Marcelo; Algarín, Cecilia; Peirano, Patricio

    2004-01-01

    An automated system for sleep spindles detection within EEG background activity, combining two different approaches, is presented. The first approach applies detection criteria on the sigma-band filtered EEG signal, including fuzzy thresholds. The second approach mimics an expert's procedure. A sleep spindle detection is validated if both approaches agree. The method was applied on a testing set, consisting of continuous sleep recordings of two patients, totaling 1132 epochs (pages). A total of 803 sleep spindles events were marked by the experts. Results showed an 87.7% agreement between the detection system and the medical experts.

  20. Human exposure to high natural background radiation: what can it teach us about radiation risks?

    PubMed Central

    Hendry, Jolyon H; Simon, Steven L; Wojcik, Andrzej; Sohrabi, Mehdi; Burkart, Werner; Cardis, Elisabeth; Laurier, Dominique; Tirmarche, Margot; Hayata, Isamu

    2014-01-01

    Natural radiation is the major source of human exposure to ionising radiation, and its largest contributing component to effective dose arises from inhalation of 222Rn and its radioactive progeny. However, despite extensive knowledge of radiation risks gained through epidemiologic investigations and mechanistic considerations, the health effects of chronic low-level radiation exposure are still poorly understood. The present paper reviews the possible contribution of studies of populations living in high natural background radiation (HNBR) areas (Guarapari, Brazil; Kerala, India; Ramsar, Iran; Yangjiang, China), including radon-prone areas, to low dose risk estimation. Much of the direct information about risk related to HNBR comes from case–control studies of radon and lung cancer, which provide convincing evidence of an association between long-term protracted radiation exposures in the general population and disease incidence. The success of these studies is mainly due to the careful organ dose reconstruction (with relatively high doses to the lung), and to the fact that large-scale collaborative studies have been conducted to maximise the statistical power and to ensure the systematic collection of information on potential confounding factors. In contrast, studies in other (non-radon) HNBR areas have provided little information, relying mainly on ecological designs and very rough effective dose categorisations. Recent steps taken in China and India to establish cohorts for follow-up and to conduct nested case–control studies may provide useful information about risks in the future, provided that careful organ dose reconstruction is possible and information is collected on potential confounding factors. PMID:19454802

  1. Molecular Mechanisms of Drug Resistance in Natural Leishmania Populations Vary with Genetic Background

    PubMed Central

    Decuypere, Saskia; Vanaerschot, Manu; Brunker, Kirstyn; Imamura, Hideo; Müller, Sylke; Khanal, Basudha; Rijal, Suman; Dujardin, Jean-Claude; Coombs, Graham H.

    2012-01-01

    The evolution of drug-resistance in pathogens is a major global health threat. Elucidating the molecular basis of pathogen drug-resistance has been the focus of many studies but rarely is it known whether a drug-resistance mechanism identified is universal for the studied pathogen; it has seldom been clarified whether drug-resistance mechanisms vary with the pathogen's genotype. Nevertheless this is of critical importance in gaining an understanding of the complexity of this global threat and in underpinning epidemiological surveillance of pathogen drug resistance in the field. This study aimed to assess the molecular and phenotypic heterogeneity that emerges in natural parasite populations under drug treatment pressure. We studied lines of the protozoan parasite Leishmania (L.) donovani with differential susceptibility to antimonial drugs; the lines being derived from clinical isolates belonging to two distinct genetic populations that circulate in the leishmaniasis endemic region of Nepal. Parasite pathways known to be affected by antimonial drugs were characterised on five experimental levels in the lines of the two populations. Characterisation of DNA sequence, gene expression, protein expression and thiol levels revealed a number of molecular features that mark antimonial-resistant parasites in only one of the two populations studied. A final series of in vitro stress phenotyping experiments confirmed this heterogeneity amongst drug-resistant parasites from the two populations. These data provide evidence that the molecular changes associated with antimonial-resistance in natural Leishmania populations depend on the genetic background of the Leishmania population, which has resulted in a divergent set of resistance markers in the Leishmania populations. This heterogeneity of parasite adaptations provides severe challenges for the control of drug resistance in the field and the design of molecular surveillance tools for widespread applicability. PMID:22389733

  2. Supercritical Fluid Chromatography--Theoretical Background and Applications on Natural Products.

    PubMed

    Hartmann, Anja; Ganzera, Markus

    2015-11-01

    The use of supercritical fluid chromatography for natural product analysis as well as underlying theoretical mechanisms and instrumental requirements are summarized in this review. A short introduction focusing on the historical development of this interesting separation technique is followed by remarks on the current instrumental design, also describing possible detection modes and useable stationary phases. The overview on relevant applications is grouped based on their basic intention, may it be (semi)preparative or purely analytical. They indicate that supercritical fluid chromatography is still primarily considered for the analysis of nonpolar analytes like carotenoids, fatty acids, or terpenes. The low polarity of supercritical carbon dioxide, which is used with modifiers almost exclusively as a mobile phase today, combined with high efficiency and fast separations might explain the popularity of supercritical fluid chromatography for the analysis of these compounds. Yet, it has been shown that more polar natural products (e.g., xanthones, flavonoids, alkaloids) are separable too, with the same (if not superior) selectivity and reproducibility than established approaches like HPLC or GC.

  3. Grounding a natural background level for fluoride in a potentially contaminated crystalline aquifer in south India.

    PubMed

    Sajil Kumar, P J

    2017-09-27

    Fluoride contamination is one of the most alarming issues for those countries that depend on groundwater drinking water supply. A careful examination of the hydrogeochemical conditions and routine monitoring of fluoride level are therefore quintessential. Estimation of natural background level (NBL) of fluoride becomes significant information for assessing the current and future contamination episodes. Vellore District in Tamil Nadu is a hard rock terrain known for its F-rich groundwater. In this study, we attempted to form a benchmark for fluoride using hydrochemical pre-selection (based on TDS and NO3) and cumulative probability plots (CPP). Principle components analysis is (PCA) applied to evaluate the corresponding factor grouping of the total of 68 samples, which is later mapped using geostatistical tool in ArcGIS. From the CPP, we derived the NBL of F as 0.75 mg/L. This value is compared with the observed concentration in each sample and they were spatially plotted based on the NBL. Resultant plot suggests that W-NW part of the study area has exceeded and E-EW regions are below the NBL of F. Spatial variation of the factor scores also supported this observation. Grounding an NBL and extending it to other parts of the potential contaminated aquifers are highly recommended for better understanding and management of the water supply systems.

  4. Enhancement of natural background gamma-radiation dose around uranium microparticles in the human body.

    PubMed

    Pattison, John E; Hugtenburg, Richard P; Green, Stuart

    2010-04-06

    Ongoing controversy surrounds the adverse health effects of the use of depleted uranium (DU) munitions. The biological effects of gamma-radiation arise from the direct or indirect interaction between secondary electrons and the DNA of living cells. The probability of the absorption of X-rays and gamma-rays with energies below about 200 keV by particles of high atomic number is proportional to the third to fourth power of the atomic number. In such a case, the more heavily ionizing low-energy recoil electrons are preferentially produced; these cause dose enhancement in the immediate vicinity of the particles. It has been claimed that upon exposure to naturally occurring background gamma-radiation, particles of DU in the human body would produce dose enhancement by a factor of 500-1000, thereby contributing a significant radiation dose in addition to the dose received from the inherent radioactivity of the DU. In this study, we used the Monte Carlo code EGSnrc to accurately estimate the likely maximum dose enhancement arising from the presence of micrometre-sized uranium particles in the body. We found that although the dose enhancement is significant, of the order of 1-10, it is considerably smaller than that suggested previously.

  5. Enhancement of natural background gamma-radiation dose around uranium microparticles in the human body

    PubMed Central

    Pattison, John E.; Hugtenburg, Richard P.; Green, Stuart

    2010-01-01

    Ongoing controversy surrounds the adverse health effects of the use of depleted uranium (DU) munitions. The biological effects of gamma-radiation arise from the direct or indirect interaction between secondary electrons and the DNA of living cells. The probability of the absorption of X-rays and gamma-rays with energies below about 200 keV by particles of high atomic number is proportional to the third to fourth power of the atomic number. In such a case, the more heavily ionizing low-energy recoil electrons are preferentially produced; these cause dose enhancement in the immediate vicinity of the particles. It has been claimed that upon exposure to naturally occurring background gamma-radiation, particles of DU in the human body would produce dose enhancement by a factor of 500–1000, thereby contributing a significant radiation dose in addition to the dose received from the inherent radioactivity of the DU. In this study, we used the Monte Carlo code EGSnrc to accurately estimate the likely maximum dose enhancement arising from the presence of micrometre-sized uranium particles in the body. We found that although the dose enhancement is significant, of the order of 1–10, it is considerably smaller than that suggested previously. PMID:19776147

  6. Doses and risks from uranium are not increased significantly by interactions with natural background photon radiation.

    PubMed

    Tanner, R J; Eakins, J S; Jansen, J T M; Harrison, J D

    2012-08-01

    The impact of depleted uranium (DU) on human health has been the subject of much conjecture. Both the chemical and radiological aspects of its behaviour in the human body have previously been investigated in detail, with the radiological impact being assumed to be linked to the alpha decay of uranium. More recently, it has been proposed that the accumulation in tissue of high-Z materials, such as DU, may give rise to enhanced local energy deposition in the presence of natural background photon radiation due to the high photoelectric interaction cross sections of high-Z atoms. It is speculated that, in addition to producing short-range photoelectrons, these events will be followed by intense Auger and Coster-Kronig electron emission, thereby causing levels of cell damage that are unaccounted for in conventional models of radiological risk. In this study, the physical and biological bases of these claims are investigated. The potential magnitudes of any effect are evaluated and discussed, and compared with the risks from other radiological or chemical hazards. Monte Carlo calculations are performed to estimate likely energy depositions due to the presence of uranium in human tissues in photon fields: whole body doses, organ doses in anthropomorphic phantoms and nano-/micro-dosimetric scenarios are each considered. The proposal is shown generally to be based on sound physics, but overall the impact on human health is expected to be negligible.

  7. Activating Student Background Knowledge in a Take Charge Approach to Foreign Language Reading.

    ERIC Educational Resources Information Center

    Young, Dolly Jesusita

    A guide for teachers of second language reading offers ideas for using authentic texts as instructional materials. The guide focuses on how to teach students to become strategic readers and use their background knowledge to enhance comprehension. Schema theory is proposed as a framework for approaching reading tasks, by providing relevant pre- and…

  8. Exploring an Activist Approach of Working with Boys from Socially Vulnerable Backgrounds in a Sport Context

    ERIC Educational Resources Information Center

    Luguetti, Carla; Oliver, Kimberly L.; Kirk, David; Dantas, Luiz

    2017-01-01

    This study explores an activist approach for co-creating a prototype pedagogical model of sport for working with boys from socially vulnerable backgrounds. This paper addresses the key features that emerged when we identified what facilitated and hindered the boys' engagement in sport. This study was an activist research project that was conducted…

  9. Estimating background-subtracted fluorescence transients in calcium imaging experiments: a quantitative approach.

    PubMed

    Joucla, Sébastien; Franconville, Romain; Pippow, Andreas; Kloppenburg, Peter; Pouzat, Christophe

    2013-08-01

    Calcium imaging has become a routine technique in neuroscience for subcellular to network level investigations. The fast progresses in the development of new indicators and imaging techniques call for dedicated reliable analysis methods. In particular, efficient and quantitative background fluorescence subtraction routines would be beneficial to most of the calcium imaging research field. A background-subtracted fluorescence transients estimation method that does not require any independent background measurement is therefore developed. This method is based on a fluorescence model fitted to single-trial data using a classical nonlinear regression approach. The model includes an appropriate probabilistic description of the acquisition system's noise leading to accurate confidence intervals on all quantities of interest (background fluorescence, normalized background-subtracted fluorescence time course) when background fluorescence is homogeneous. An automatic procedure detecting background inhomogeneities inside the region of interest is also developed and is shown to be efficient on simulated data. The implementation and performances of the proposed method on experimental recordings from the mouse hypothalamus are presented in details. This method, which applies to both single-cell and bulk-stained tissues recordings, should help improving the statistical comparison of fluorescence calcium signals between experiments and studies. Copyright © 2013 Elsevier Ltd. All rights reserved.

  10. Diffusion-assisted selective dynamical recoupling: A new approach to measure background gradients in magnetic resonance

    NASA Astrophysics Data System (ADS)

    Álvarez, Gonzalo A.; Shemesh, Noam; Frydman, Lucio

    2014-02-01

    Dynamical decoupling, a generalization of the original NMR spin-echo sequence, is becoming increasingly relevant as a tool for reducing decoherence in quantum systems. Such sequences apply non-equidistant refocusing pulses for optimizing the coupling between systems, and environmental fluctuations characterized by a given noise spectrum. One such sequence, dubbed Selective Dynamical Recoupling (SDR) [P. E. S. Smith, G. Bensky, G. A. Álvarez, G. Kurizki, and L. Frydman, Proc. Natl. Acad. Sci. 109, 5958 (2012)], allows one to coherently reintroduce diffusion decoherence effects driven by fluctuations arising from restricted molecular diffusion [G. A. Álvarez, N. Shemesh, and L. Frydman, Phys. Rev. Lett. 111, 080404 (2013)]. The fully-refocused, constant-time, and constant-number-of-pulses nature of SDR also allows one to filter out "intrinsic" T1 and T2 weightings, as well as pulse errors acting as additional sources of decoherence. This article explores such features when the fluctuations are now driven by unrestricted molecular diffusion. In particular, we show that diffusion-driven SDR can be exploited to investigate the decoherence arising from the frequency fluctuations imposed by internal gradients. As a result, SDR presents a unique way of probing and characterizing these internal magnetic fields, given an a priori known free diffusion coefficient. This has important implications in studies of structured systems, including porous media and live tissues, where the internal gradients may serve as fingerprints for the system's composition or structure. The principles of this method, along with full analytical solutions for the unrestricted diffusion-driven modulation of the SDR signal, are presented. The potential of this approach is demonstrated with the generation of a novel source of MRI contrast, based on the background gradients active in an ex vivo mouse brain. Additional features and limitations of this new method are discussed.

  11. Diffusion-assisted selective dynamical recoupling: A new approach to measure background gradients in magnetic resonance

    SciTech Connect

    Álvarez, Gonzalo A.; Shemesh, Noam; Frydman, Lucio

    2014-02-28

    Dynamical decoupling, a generalization of the original NMR spin-echo sequence, is becoming increasingly relevant as a tool for reducing decoherence in quantum systems. Such sequences apply non-equidistant refocusing pulses for optimizing the coupling between systems, and environmental fluctuations characterized by a given noise spectrum. One such sequence, dubbed Selective Dynamical Recoupling (SDR) [P. E. S. Smith, G. Bensky, G. A. Álvarez, G. Kurizki, and L. Frydman, Proc. Natl. Acad. Sci. 109, 5958 (2012)], allows one to coherently reintroduce diffusion decoherence effects driven by fluctuations arising from restricted molecular diffusion [G. A. Álvarez, N. Shemesh, and L. Frydman, Phys. Rev. Lett. 111, 080404 (2013)]. The fully-refocused, constant-time, and constant-number-of-pulses nature of SDR also allows one to filter out “intrinsic” T{sub 1} and T{sub 2} weightings, as well as pulse errors acting as additional sources of decoherence. This article explores such features when the fluctuations are now driven by unrestricted molecular diffusion. In particular, we show that diffusion-driven SDR can be exploited to investigate the decoherence arising from the frequency fluctuations imposed by internal gradients. As a result, SDR presents a unique way of probing and characterizing these internal magnetic fields, given an a priori known free diffusion coefficient. This has important implications in studies of structured systems, including porous media and live tissues, where the internal gradients may serve as fingerprints for the system's composition or structure. The principles of this method, along with full analytical solutions for the unrestricted diffusion-driven modulation of the SDR signal, are presented. The potential of this approach is demonstrated with the generation of a novel source of MRI contrast, based on the background gradients active in an ex vivo mouse brain. Additional features and limitations of this new method are discussed.

  12. Computational approaches to natural product discovery

    PubMed Central

    Medema, Marnix H.; Fischbach, Michael A.

    2016-01-01

    From the earliest Streptomyces genome sequences, the promise of natural product genome mining has been captivating: genomics and bioinformatics would transform compound discovery from an ad hoc pursuit to a high-throughput endeavor. Until recently, however, genome mining has advanced natural product discovery only modestly. Here, we argue that the development of algorithms to mine the continuously increasing amounts of (meta)genomic data will enable the promise of genome mining to be realized. We review computational strategies that have been developed to identify biosynthetic gene clusters in genome sequences and predict the chemical structures of their products. We then discuss networking strategies that can systematize large volumes of genetic and chemical data, and connect genomic information to metabolomic and phenotypic data. Finally, we provide a vision of what natural product discovery might look like in the future, specifically considering long-standing questions in microbial ecology regarding the roles of metabolites in interspecies interactions. PMID:26284671

  13. Computational approaches to natural product discovery.

    PubMed

    Medema, Marnix H; Fischbach, Michael A

    2015-09-01

    Starting with the earliest Streptomyces genome sequences, the promise of natural product genome mining has been captivating: genomics and bioinformatics would transform compound discovery from an ad hoc pursuit to a high-throughput endeavor. Until recently, however, genome mining has advanced natural product discovery only modestly. Here, we argue that the development of algorithms to mine the continuously increasing amounts of (meta)genomic data will enable the promise of genome mining to be realized. We review computational strategies that have been developed to identify biosynthetic gene clusters in genome sequences and predict the chemical structures of their products. We then discuss networking strategies that can systematize large volumes of genetic and chemical data and connect genomic information to metabolomic and phenotypic data. Finally, we provide a vision of what natural product discovery might look like in the future, specifically considering longstanding questions in microbial ecology regarding the roles of metabolites in interspecies interactions.

  14. A Natural Approach to the Number "e"

    ERIC Educational Resources Information Center

    Doerr, Helen M.; Meehan, Donna J.; O'Neil, AnnMarie H.

    2012-01-01

    In this article, the authors introduce the value of "e" by building on students' prior knowledge of slope and using their abilities to analyze, approximate, and interpret rates of change using graphs, symbols, and numerical data. This approach allows students to construct and interpret the value of "e" while laying the conceptual foundation for…

  15. A Natural Approach to the Number "e"

    ERIC Educational Resources Information Center

    Doerr, Helen M.; Meehan, Donna J.; O'Neil, AnnMarie H.

    2012-01-01

    In this article, the authors introduce the value of "e" by building on students' prior knowledge of slope and using their abilities to analyze, approximate, and interpret rates of change using graphs, symbols, and numerical data. This approach allows students to construct and interpret the value of "e" while laying the conceptual foundation for…

  16. Phylogenetic approaches to natural product structure prediction.

    PubMed

    Ziemert, Nadine; Jensen, Paul R

    2012-01-01

    Phylogenetics is the study of the evolutionary relatedness among groups of organisms. Molecular phylogenetics uses sequence data to infer these relationships for both organisms and the genes they maintain. With the large amount of publicly available sequence data, phylogenetic inference has become increasingly important in all fields of biology. In the case of natural product research, phylogenetic relationships are proving to be highly informative in terms of delineating the architecture and function of the genes involved in secondary metabolite biosynthesis. Polyketide synthases and nonribosomal peptide synthetases provide model examples in which individual domain phylogenies display different predictive capacities, resolving features ranging from substrate specificity to structural motifs associated with the final metabolic product. This chapter provides examples in which phylogeny has proven effective in terms of predicting functional or structural aspects of secondary metabolism. The basics of how to build a reliable phylogenetic tree are explained along with information about programs and tools that can be used for this purpose. Furthermore, it introduces the Natural Product Domain Seeker, a recently developed Web tool that employs phylogenetic logic to classify ketosynthase and condensation domains based on established enzyme architecture and biochemical function. Copyright © 2012 Elsevier Inc. All rights reserved.

  17. Natural products: a safest approach for obesity.

    PubMed

    Vasudeva, Neeru; Yadav, Neerja; Sharma, Surendra Kumar

    2012-06-01

    Obesity is recognized as a social problem, associated with serious health risks and increased mortality. Numerous trials have been conducted to find and develop new anti-obesity drugs through herbal sources to minimize adverse reactions associated with the present anti-obesity drugs. The use of natural products as medicine has been documented for hundreds of years in various traditional systems of medicines throughout the world. This review focuses on the medicinal plants such as Achyranthus aspera, Camellia sinensis, Emblica officinalis, Garcinia cambogia, Terminalia arjuna, etc., being used traditionally in Ayurvedic, Unani, Siddha and Chinese, etc., systems of medicine. The review also highlights recent reported phytochemicals such as escins, perennisosides, dioscin, gracillin, etc., and the various extracts of the plants like Nelumbo nucifera, Panax japonicas, Cichorium intybus, Cyperus rotundus, Paeonia suffruticosa, etc., which have been successfully identified for the treatment of obesity.

  18. Defining mental disorder. Exploring the 'natural function' approach

    PubMed Central

    2011-01-01

    Due to several socio-political factors, to many psychiatrists only a strictly objective definition of mental disorder, free of value components, seems really acceptable. In this paper, I will explore a variant of such an objectivist approach to defining metal disorder, natural function objectivism. Proponents of this approach make recourse to the notion of natural function in order to reach a value-free definition of mental disorder. The exploration of Christopher Boorse's 'biostatistical' account of natural function (1) will be followed an investigation of the 'hybrid naturalism' approach to natural functions by Jerome Wakefield (2). In the third part, I will explore two proposals that call into question the whole attempt to define mental disorder (3). I will conclude that while 'natural function objectivism' accounts fail to provide the backdrop for a reliable definition of mental disorder, there is no compelling reason to conclude that a definition cannot be achieved. PMID:21255405

  19. Defining mental disorder. Exploring the 'natural function' approach.

    PubMed

    Varga, Somogy

    2011-01-21

    Due to several socio-political factors, to many psychiatrists only a strictly objective definition of mental disorder, free of value components, seems really acceptable. In this paper, I will explore a variant of such an objectivist approach to defining metal disorder, natural function objectivism. Proponents of this approach make recourse to the notion of natural function in order to reach a value-free definition of mental disorder. The exploration of Christopher Boorse's 'biostatistical' account of natural function (1) will be followed an investigation of the 'hybrid naturalism' approach to natural functions by Jerome Wakefield (2). In the third part, I will explore two proposals that call into question the whole attempt to define mental disorder (3). I will conclude that while 'natural function objectivism' accounts fail to provide the backdrop for a reliable definition of mental disorder, there is no compelling reason to conclude that a definition cannot be achieved.

  20. Holistic approach for automated background EEG assessment in asphyxiated full-term infants

    NASA Astrophysics Data System (ADS)

    Matic, Vladimir; Cherian, Perumpillichira J.; Koolen, Ninah; Naulaers, Gunnar; Swarte, Renate M.; Govaert, Paul; Van Huffel, Sabine; De Vos, Maarten

    2014-12-01

    Objective. To develop an automated algorithm to quantify background EEG abnormalities in full-term neonates with hypoxic ischemic encephalopathy. Approach. The algorithm classifies 1 h of continuous neonatal EEG (cEEG) into a mild, moderate or severe background abnormality grade. These classes are well established in the literature and a clinical neurophysiologist labeled 272 1 h cEEG epochs selected from 34 neonates. The algorithm is based on adaptive EEG segmentation and mapping of the segments into the so-called segments’ feature space. Three features are suggested and further processing is obtained using a discretized three-dimensional distribution of the segments’ features represented as a 3-way data tensor. Further classification has been achieved using recently developed tensor decomposition/classification methods that reduce the size of the model and extract a significant and discriminative set of features. Main results. Effective parameterization of cEEG data has been achieved resulting in high classification accuracy (89%) to grade background EEG abnormalities. Significance. For the first time, the algorithm for the background EEG assessment has been validated on an extensive dataset which contained major artifacts and epileptic seizures. The demonstrated high robustness, while processing real-case EEGs, suggests that the algorithm can be used as an assistive tool to monitor the severity of hypoxic insults in newborns.

  1. The effects of natural variation in background radioactivity on humans, animals and other organisms.

    PubMed

    Møller, Anders P; Mousseau, Timothy A

    2013-02-01

    Natural levels of radioactivity on the Earth vary by more than a thousand-fold; this spatial heterogeneity may suffice to create heterogeneous effects on physiology, mutation and selection. We review the literature on the relationship between variation in natural levels of radioactivity and evolution. First, we consider the effects of natural levels of radiation on mutations, DNA repair and genetics. A total of 46 studies with 373 effect size estimates revealed a small, but highly significant mean effect that was independent of adjustment for publication bias. Second, we found different mean effect sizes when studies were based on broad categories like physiology, immunology and disease frequency; mean weighted effect sizes were larger for studies of plants than animals, and larger in studies conducted in areas with higher levels of radiation. Third, these negative effects of radiation on mutations, immunology and life history are inconsistent with a general role of hormetic positive effects of radiation on living organisms. Fourth, we reviewed studies of radiation resistance among taxa. These studies suggest that current levels of natural radioactivity may affect mutational input and thereby the genetic constitution and composition of natural populations. Susceptibility to radiation varied among taxa, and several studies provided evidence of differences in susceptibility among populations or strains. Crucially, however, these studies are few and scattered, suggesting that a concerted effort to address this lack of research should be made. © 2012 The Authors. Biological Reviews © 2012 Cambridge Philosophical Society.

  2. Medical students from natural science and nonscience undergraduate backgrounds. Similar academic performance and residency selection.

    PubMed

    Dickman, R L; Sarnacki, R E; Schimpfhauser, F T; Katz, L A

    1980-06-27

    The majority of matriculating US medical students continue to major in the natural sciences as college undergraduates in the belief that this will enhance their chances of admission to and their performance in medical school. The present study compared the academic performance and residency selection of natural science and nonscience majors in three separate medical school classes at the State University of New York at Buffalo. Statistical analysis of grades in the first two years of medical school, clinical performance in the third year, and part I and part II National Board Medical Examination scores revealed no significant differences across three class replications. Residency selection among graduating seniors was also independent of undergraduate major. It is suggested that admissions committees, premedical advisors, and students reconsider their attitudes about the necessity of concentration in the natural sciences before entering medical school.

  3. Neutron inelastic scattering in natural Cu as a background in neutrinoless double-β decay experiments

    NASA Astrophysics Data System (ADS)

    Boswell, M. S.; Elliott, S. R.; Perepelitsa, D. V.; Devlin, M.; Fotiades, N.; Nelson, R. O.; Kawano, T.; Guiseppe, V. E.

    2013-06-01

    Background: Experiments designed to study rare processes, such as neutrinoless double-β decay (0νββ), are crucial tests for physics beyond the standard model. These experiments rely on reducing the intrinsic radioactive background to unprecedented levels, while adequately shielding the detectors from external sources of radioactivity.Purpose: The purpose of this work is focused on understanding the background rates from neutron interactions in Cu shielding in regions around the Q values of many candidate 0νββ decay isotopes, as well as providing data for benchmarking Monte Carlo simulations of background events.Methods: Using the broad-spectrum neutron beam at Los Alamos Neutron Science Center, we have measured γ rays emitted from inelastic neutron scattering on natCu.Results: We extracted the level cross sections from the γ-production cross section for 46 energy levels in natCu. These level cross sections were compared with the available experimental data, as well as the ENDF/B-VII evaluation for discrete levels.Conclusions: For energy levels above 2 MeV we found significant discrepancies between the suggested level cross sections for both nuclei and our data. We found reasonable agreement between our measurement and the ENDF/B-VII evaluation for the total neutron inelastic cross section in 63Cu. Our measurement of the total neutron inelastic scattering cross section in 65Cu was 30% lower than the ENDF/B-VII evaluations, which we attribute to unobserved transitions in 65Cu. Furthermore, we found that the implementation of the ENDF/B-VII evaluation in simulations did not properly model the decay properties of the nucleus to the degree necessary for estimating backgrounds in rear-event searches. Finally, we examined the potential implications of our measurements on 0νββ measurements and found that many of the commonly studied 0νββ isotopes had Q values below the cutoff for ENDF/B-VII evaluated discrete levels in either Cu nucleus.

  4. Simple approach to predict APD/PMT lidar detector performance under sky background using dimensionless parametrization

    NASA Astrophysics Data System (ADS)

    Agishev, Ravil; Gross, Barry; Moshary, Fred; Gilerson, Alexander; Ahmed, Samir

    2006-08-01

    In this paper, we developed a simple approach to predict the APD/PMT (avalanche photodiode/photomultiplier) lidar detector performance in the presence of residual skylight background. By normalizing all relevant photodetector noise sources to the quantum noise, we obtain quantitative expressions for the degradation of the signal-to-noise ratio (SNR), the increasing threshold sensitivity of and decreasing lidar operation range. To apply the formalism to any lidar photodetectors operating in the ultra violet, visible and near-infrared spectral regions and to perform a comparative analysis of PMT and APD capabilities as the best photodetectors for ultra-violet (UV), visible (Vis) and near infra-red (NIR) lidar, we utilize a set of spectral characteristics that are built from an envelope of individual PMT and APD component responses. On this basis, the general analysis of system performance under intense background conditions is developed, and practical recommendations on detector use for each spectral region are given. The dimensionless formalism and the generalized detector spectral models used allows our analysis to be applied to nearly any lidar receiver operating over very different signal/background situations.

  5. Categorization of Natural Whistled Vowels by Naïve Listeners of Different Language Background.

    PubMed

    Meyer, Julien; Dentel, Laure; Meunier, Fanny

    2017-01-01

    Whistled speech in a non-tonal language consists of the natural emulation of vocalic and consonantal qualities in a simple modulated whistled signal. This special speech register represents a natural telecommunication system that enables high levels of sentence intelligibility by trained speakers and is not directly intelligible to naïve listeners. Yet, it is easily learned by speakers of the language that is being whistled, as attested by the current efforts of the revitalization of whistled Spanish in the Canary Islands. To better understand the relation between whistled and spoken speech perception, we look herein at how Spanish, French, and Standard Chinese native speakers, knowing nothing about whistled speech, categorized four Spanish whistled vowels. The results show that the listeners categorized differently depending on their native language. The Standard Chinese speakers demonstrated the worst performance on this task but were still able to associate a tonal whistle to vowel categories. Spanish speakers were the most accurate, and both Spanish and French participants were able to categorize the four vowels, although not as accurately as an expert whistler. These results attest that whistled speech can be used as a natural laboratory to test the perceptual processes of language.

  6. Categorization of Natural Whistled Vowels by Naïve Listeners of Different Language Background

    PubMed Central

    Meyer, Julien; Dentel, Laure; Meunier, Fanny

    2017-01-01

    Whistled speech in a non-tonal language consists of the natural emulation of vocalic and consonantal qualities in a simple modulated whistled signal. This special speech register represents a natural telecommunication system that enables high levels of sentence intelligibility by trained speakers and is not directly intelligible to naïve listeners. Yet, it is easily learned by speakers of the language that is being whistled, as attested by the current efforts of the revitalization of whistled Spanish in the Canary Islands. To better understand the relation between whistled and spoken speech perception, we look herein at how Spanish, French, and Standard Chinese native speakers, knowing nothing about whistled speech, categorized four Spanish whistled vowels. The results show that the listeners categorized differently depending on their native language. The Standard Chinese speakers demonstrated the worst performance on this task but were still able to associate a tonal whistle to vowel categories. Spanish speakers were the most accurate, and both Spanish and French participants were able to categorize the four vowels, although not as accurately as an expert whistler. These results attest that whistled speech can be used as a natural laboratory to test the perceptual processes of language. PMID:28174545

  7. Natural hydrocarbon background in benthic sediments of Prince William Sound, Alaska: Oil vs coal

    USGS Publications Warehouse

    Short, J.W.; Kvenvolden, K.A.; Carlson, P.R.; Hostettler, F.D.; Rosenbauer, R.J.; Wright, B.A.

    1999-01-01

    The source of the background hydrocarbons in benthic sediments of Prince William Sound (PWS), AK, where the 1989 Exxon Valdez oil spill (EVOS) occurred, has been ascribed to oil seeps in coastal areas of the Gulf of Alaska (GOA). We present evidence that coal is a more plausible source, including (i) high concentrations of total PAH (TPAH), between 1670 and 3070 ng/g, in continental shelf sediments adjacent to the coastal region containing extensive coal deposits; (ii) PAH composition patterns of sediments along with predictive models that are consistent with coal but not oil; (iii) low ratios (<0.2) of triaromatic steranes to methylchrysenes found in sediments and coals, contrasting with the high ratios (11 and 13) found in seep oil; and (iv) bioaccumulation of PAH in salmon collected within 100 m of the Katalla oil seeps but not in filter-feeding mussels collected near oilfield drainages 9 km from the seeps, indicating negligible transport of bioavailable PAH from Katalla seeps to the GOA. In contrast with oil, PAH in coal are not bioavailable, so the presence of coal in these benthic sediments confers no adaptive benefit to biota of the marine ecosystem with respect to PAH insults from anthropogenic sources.The source of the background hydrocarbons in benthic sediments of Prince William Sound (PWS), AK, where the 1989 Exxon Valdez oil spill (EVOS) occurred, has been ascribed to oil seeps in coastal areas of the Gulf of Alaska (GOA). We present evidence that coal is a more plausible source, including (i) high concentrations of total PAH (TPAH), between 1670 and 3070 ng/g, in continental shelf sediments adjacent to the coastal region containing extensive coal deposits; (ii) PAH composition patterns of sediments along with predictive models that are consistent with coal but not oil; (iii) low ratios (<0.2) of triaromatic steranes to methylchrysenes found in sediments and coals, contrasting with the high ratios (11 and 13) found in seep oil; and (iv) bioaccumulation

  8. A new line-of-sight approach to the non-linear Cosmic Microwave Background

    SciTech Connect

    Fidler, Christian; Koyama, Kazuya; Pettinari, Guido W. E-mail: kazuya.koyama@port.ac.uk

    2015-04-01

    We develop the transport operator formalism, a new line-of-sight integration framework to calculate the anisotropies of the Cosmic Microwave Background (CMB) at the linear and non-linear level. This formalism utilises a transformation operator that removes all inhomogeneous propagation effects acting on the photon distribution function, thus achieving a split between perturbative collisional effects at recombination and non-perturbative line-of-sight effects at later times. The former can be computed in the framework of standard cosmological perturbation theory with a second-order Boltzmann code such as SONG, while the latter can be treated within a separate perturbative scheme allowing the use of non-linear Newtonian potentials. We thus provide a consistent framework to compute all physical effects contained in the Boltzmann equation and to combine the standard remapping approach with Boltzmann codes at any order in perturbation theory, without assuming that all sources are localised at recombination.

  9. A new line-of-sight approach to the non-linear Cosmic Microwave Background

    NASA Astrophysics Data System (ADS)

    Fidler, Christian; Koyama, Kazuya; Pettinari, Guido W.

    2015-04-01

    We develop the transport operator formalism, a new line-of-sight integration framework to calculate the anisotropies of the Cosmic Microwave Background (CMB) at the linear and non-linear level. This formalism utilises a transformation operator that removes all inhomogeneous propagation effects acting on the photon distribution function, thus achieving a split between perturbative collisional effects at recombination and non-perturbative line-of-sight effects at later times. The former can be computed in the framework of standard cosmological perturbation theory with a second-order Boltzmann code such as SONG, while the latter can be treated within a separate perturbative scheme allowing the use of non-linear Newtonian potentials. We thus provide a consistent framework to compute all physical effects contained in the Boltzmann equation and to combine the standard remapping approach with Boltzmann codes at any order in perturbation theory, without assuming that all sources are localised at recombination.

  10. An Approach to Extract Moving Objects from Mls Data Using a Volumetric Background Representation

    NASA Astrophysics Data System (ADS)

    Gehrung, J.; Hebel, M.; Arens, M.; Stilla, U.

    2017-05-01

    Data recorded by mobile LiDAR systems (MLS) can be used for the generation and refinement of city models or for the automatic detection of long-term changes in the public road space. Since for this task only static structures are of interest, all mobile objects need to be removed. This work presents a straightforward but powerful approach to remove the subclass of moving objects. A probabilistic volumetric representation is utilized to separate MLS measurements recorded by a Velodyne HDL-64E into mobile objects and static background. The method was subjected to a quantitative and a qualitative examination using multiple datasets recorded by a mobile mapping platform. The results show that depending on the chosen octree resolution 87-95% of the measurements are labeled correctly.

  11. Natural radionuclide and radiological assessment of building materials in high background radiation areas of Ramsar, Iran

    PubMed Central

    Bavarnegin, Elham; Moghaddam, Masoud Vahabi; Fathabadi, Nasrin

    2013-01-01

    Building materials, collected from different sites in Ramsar, a northern coastal city in Iran, were analyzed for their natural radionuclide contents. The measurements were carried out using a high resolution high purity Germanium (HPGe) gamma-ray spectrometer system. The activity concentration of 226Ra, 232Th, and 40K content varied from below the minimum detection limit up to 86,400 Bqkg-1, 187 Bqkg-1, and 1350 Bqkg-1, respectively. The radiological hazards incurred from the use of these building materials were estimated through various radiation hazard indices. The result of this survey shows that values obtained for some samples are more than the internationally accepted maximum limits and as such, the use of them as a building material pose significant radiation hazard to individuals. PMID:23776313

  12. Natural radionuclide and radiological assessment of building materials in high background radiation areas of Ramsar, Iran.

    PubMed

    Bavarnegin, Elham; Moghaddam, Masoud Vahabi; Fathabadi, Nasrin

    2013-04-01

    Building materials, collected from different sites in Ramsar, a northern coastal city in Iran, were analyzed for their natural radionuclide contents. The measurements were carried out using a high resolution high purity Germanium (HPGe) gamma-ray spectrometer system. The activity concentration of (226)Ra, (232)Th, and (40)K content varied from below the minimum detection limit up to 86,400 Bqkg(-1), 187 Bqkg(-1), and 1350 Bqkg(-1), respectively. The radiological hazards incurred from the use of these building materials were estimated through various radiation hazard indices. The result of this survey shows that values obtained for some samples are more than the internationally accepted maximum limits and as such, the use of them as a building material pose significant radiation hazard to individuals.

  13. U.S. -- EC fuel cycle study: Background document to the approach and issues

    SciTech Connect

    Cantor, Robin; Russell, Lee; Krupnick, Alan; Smith, Hilary; Schaffhauser, Jr., A.; Barnthouse, Larry; Cada, Glen; Kroodsma, Roger; Turner, Robb; Easterly, Clay; Jones, Troyce; Burtraw, Dallas; Harrington, Winston; Freeman, A. Myrick

    1992-11-01

    In February 1991, DOE and the Commission of the European Communities (EC), signed a joint statement regarding the external costs of fuel cycles. This 18-month agreement committed their respective organizations to develop a comparative analytical methodology and to develop the best range of estimates of external costs from secondary sources'' for eight fuel cycles and four conservation options. In our study, a fuel cycle is defined as the series of physical and chemical processes and activities that are required to generate electricity from a specific fuel or resource. This foundation phase of the study is primarily limited to developing and demonstrating methods for estimating impacts and their monetized value, what we term damages'' or benefits,'' leaving aside the extent to which such damages have been internalized. However, Appendix C provides the conceptual framework for evaluating the extent of internalization. This report is a background document to introduce the study approach and to discuss the major conceptual and practical issues entailed by the incremental damage problem. As a background document, the report seeks to communicate an overview of the study and the important methodological choices that were made to conduct the research. In successive sections of the report, the methodological tools used in the study are discussed; the ecological and health impacts are reviewed using the coal fuel cycle as a reference case; and, in the final chapter, the methods for valuing impacts are detailed.

  14. Natural hydrocarbon background in benthic sediments of Prince William Sound, Alaska: Oil vs coal

    SciTech Connect

    Short, J.W.; Wright, B.A.; Kvenvolden, K.A.; Carlson, P.R.; Hostettler, F.D.; Rosenbauer, R.J.

    1999-01-01

    The source of the background hydrocarbons in benthic sediments of Prince William Sound (PWS), AK, where the 1989 Exxon Valdez oil spill (EVOS) occurred, has been ascribed to oil seeps in coastal areas of the Gulf of Alaska (GOA). The authors present evidence that coal is a more plausible source, including (i) high concentrations of total PAH (TPAH), between 1,670 and 3,070 ng/g, in continental shelf sediments adjacent to the coastal region containing extensive coal deposits; (ii) PAH composition patterns of sediments along with predictive models that are consistent with coal but not oil; (iii) low ratios of triaromatic steranes of methylchrysenes found in sediments and coals, contrasting with the high ratios found in seep oil; and (iv) bioaccumulation of PAH in salmon collected within 100 m of the Katalla oil seeps but not in filter-feeding mussels collected near oilfield drainages 9 km from the seeps, indicating negligible transport of bioavailable PAH from Katalla seeps to the GOA. In contrast with oil, PAH in coal are not bioavailable, so the presence of coal in these benthic sediments confers no adaptive benefit to biota of the marine ecosystem with respect to PAH insults from anthropogenic sources.

  15. The Nature of the Unresolved Extragalactic Cosmic Soft X-Ray Background

    NASA Technical Reports Server (NTRS)

    Cappelluti, N.; Ranalli, P.; Roncarelli, M.; Arevalo, P.; Zamorani, G.; Comastri, A.; Gilli, R.; Rovilos, E.; Vignali, C.; Allevato, V.; hide

    2013-01-01

    In this paper we investigate the power spectrum of the unresolved 0.5-2 keV cosmic X-ray background (CXB) with deep Chandra 4-Msec (Ms) observations in the Chandra Deep Field South (CDFS). We measured a signal that, on scales >30 arcsec, is significantly higher than the shot noise and is increasing with angular scale. We interpreted this signal as the joint contribution of clustered undetected sources like active galactic nuclei (AGN), galaxies and the intergalactic medium (IGM). The power of unresolved cosmic source fluctuations accounts for approximately 12 per cent of the 0.5-2 keV extragalactic CXB. Overall, our modelling predicts that approximately 20 per cent of the unresolved CXB flux is produced by low-luminosity AGN, approximately 25 per cent by galaxies and approximately 55 per cent by the IGM. We do not find any direct evidence of the so-called 'warm hot intergalactic medium' (i.e. matter with 10(exp 5) less than T less than 10(exp 7) K and density contrast delta less than 1000), but we estimated that it could produce about 1/7 of the unresolved CXB. We placed an upper limit on the space density of postulated X-ray-emitting early black holes at z greater than 7.5 and compared it with supermassive black hole evolution models.

  16. Wound healing: time to look for intelligent, 'natural' immunological approaches?

    PubMed

    Garraud, Olivier; Hozzein, Wael N; Badr, Gamal

    2017-06-21

    There is now good evidence that cytokines and growth factors are key factors in tissue repair and often exert anti-infective activities. However, engineering such factors for global use, even in the most remote places, is not realistic. Instead, we propose to examine how such factors work and to evaluate the reparative tools generously provided by 'nature.' We used two approaches to address these objectives. The first approach was to reappraise the internal capacity of the factors contributing the most to healing in the body, i.e., blood platelets. The second was to revisit natural agents such as whey proteins, (honey) bee venom and propolis. The platelet approach elucidates the inflammation spectrum from physiology to pathology, whereas milk and honey derivatives accelerate diabetic wound healing. Thus, this review aims at offering a fresh view of how wound healing can be addressed by natural means.

  17. Approaches to modelling uranium (VI) adsorption on natural mineral assemblages

    USGS Publications Warehouse

    Waite, T.D.; Davis, J.A.; Fenton, B.R.; Payne, T.E.

    2000-01-01

    Component additivity (CA) and generalised composite (GC) approaches to deriving a suitable surface complexation model for description of U(VI) adsorption to natural mineral assemblages are pursued in this paper with good success. A single, ferrihydrite-like component is found to reasonably describe uranyl uptake to a number of kaolinitic iron-rich natural substrates at pH > 4 in the CA approach with previously published information on nature of surface complexes, acid-base properties of surface sites and electrostatic effects used in the model. The GC approach, in which little pre-knowledge about generic surface sites is assumed, gives even better fits and would appear to be a method of particular strength for application in areas such as performance assessment provided the model is developed in a careful, stepwise manner with simplicity and goodness of fit as the major criteria for acceptance.

  18. Blurring the Inputs: A Natural Language Approach to Sensitivity Analysis

    NASA Technical Reports Server (NTRS)

    Kleb, William L.; Thompson, Richard A.; Johnston, Christopher O.

    2007-01-01

    To document model parameter uncertainties and to automate sensitivity analyses for numerical simulation codes, a natural-language-based method to specify tolerances has been developed. With this new method, uncertainties are expressed in a natural manner, i.e., as one would on an engineering drawing, namely, 5.25 +/- 0.01. This approach is robust and readily adapted to various application domains because it does not rely on parsing the particular structure of input file formats. Instead, tolerances of a standard format are added to existing fields within an input file. As a demonstration of the power of this simple, natural language approach, a Monte Carlo sensitivity analysis is performed for three disparate simulation codes: fluid dynamics (LAURA), radiation (HARA), and ablation (FIAT). Effort required to harness each code for sensitivity analysis was recorded to demonstrate the generality and flexibility of this new approach.

  19. Outdoor (222)Rn-concentrations in Germany - part 1 - natural background.

    PubMed

    Kümmel, M; Dushe, C; Müller, S; Gehrcke, K

    2014-06-01

    To determine the natural radiation exposure due to outdoor radon ((222)Rn) and its short-lived decay products in Germany, the Federal Office for Radiation Protection (BfS) conducted a measuring programme over three years. The annual mean radon concentration at 1.5 m above ground level was measured with solid-state track etch detectors at 173 measuring points in an even grid with a grid length of approx. 50 km. Furthermore, annual mean values of the equilibrium-equivalent radon concentration (EEC) and the equilibrium factor were estimated on the basis of the activity concentrations of (214)Pb and (214)Bi measured at 27 stations of the German Meteorological Service (DWD). Our study yielded a spatial mean outdoor radon concentration for Germany of 9 ± 1 Bq m(-3) (median: 8 (-0.5/+1.0) Bq m(-3)), with regional means varying from 4.5 Bq m(-3) in Hamburg to 14 Bq m(-3) in Bavaria. The determined EEC are in a range from 1.4 to 11 Bq m(-3).

  20. Amputations in natural disasters and mass casualties: staged approach.

    PubMed

    Wolfson, Nikolaj

    2012-10-01

    Amputation is a commonly performed procedure during natural disasters and mass casualties related to industrial accidents and military conflicts where large civilian populations are subjected to severe musculoskeletal trauma. Crush injuries and crush syndrome, an often-overwhelming number of casualties, delayed presentations, regional cultural and other factors, all can mandate a surgical approach to amputation that is different than that typically used under non-disaster conditions. The following article will review the subject of amputation during natural disasters and mass casualties with emphasis on a staged approach to minimise post-surgical complications, especially infection.

  1. Cutaneous delivery of natural antioxidants: the enhancement approaches.

    PubMed

    Aljuffali, Ibrahim A; Hsu, Ching-Yun; Lin, Yin-Ku; Fang, Jia-You

    2015-01-01

    Topically applied natural antioxidants can be an effective treatment for inhibiting oxidative damage and photoaging of the skin. Due to the barrier function of the stratum corneum (SC), it is necessary to use an enhancement approach to promote the cutaneous absorption of natural antioxidants. Some factors that should be considered when developing delivery systems for natural antioxidants include increased solubility, enhanced storage stability, improved permeability and bioavailability, skin targeting, and minimal side effects. This review describes the skin delivery systems for natural antioxidant permeation that have been developed during the last decade. The antioxidants introduced include vitamins, polyphenols, and carotenoids. Various types of formulations are employed to improve the skin penetration of the antioxidants, such as hydrogels, cyclodextrin, microemulsions, nanoparticles, liposomes and niosomes. This review focuses on the introduction of natural antioxidants used in skin protection, the mechanisms of antioxidant activity on the skin, and formulation designs for enhancing absorption and efficacy.

  2. Patterns of Population Differentiation and Natural Selection on the Celiac Disease Background Risk Network

    PubMed Central

    Sams, Aaron; Hawks, John

    2013-01-01

    Celiac disease is a common small intestinal inflammatory condition induced by wheat gluten and related proteins from rye and barley. Left untreated, the clinical presentation of CD can include failure to thrive, malnutrition, and distension in juveniles. The disease can additionally lead to vitamin deficiencies, anemia, and osteoporosis. Therefore, CD potentially negatively affected fitness in past populations utilizing wheat, barley, and rye. Previous analyses of CD risk variants have uncovered evidence for positive selection on some of these loci. These studies also suggest the possibility that risk for common autoimmune conditions such as CD may be the result of positive selection on immune related loci in the genome to fight infection. Under this evolutionary scenario, disease phenotypes may be a trade-off from positive selection on immunity. If this hypothesis is generally true, we can expect to find a signal of natural selection when we survey across the network of loci known to influence CD risk. This study examines the non-HLA autosomal network of gene loci associated with CD risk in Europe. We reject the null hypothesis of neutrality on this network of CD risk loci. Additionally, we can localize evidence of selection in time and space by adding information from the genome of the Tyrolean Iceman. While we can show significant differentiation between continental regions across the CD network, the pattern of evidence is not consistent with primarily recent (Holocene) selection across this network in Europe. Further localization of ancient selection on this network may illuminate the ecological pressures acting on the immune system during this critically interesting phase of our evolution. PMID:23936230

  3. Patterns of population differentiation and natural selection on the celiac disease background risk network.

    PubMed

    Sams, Aaron; Hawks, John

    2013-01-01

    Celiac disease is a common small intestinal inflammatory condition induced by wheat gluten and related proteins from rye and barley. Left untreated, the clinical presentation of CD can include failure to thrive, malnutrition, and distension in juveniles. The disease can additionally lead to vitamin deficiencies, anemia, and osteoporosis. Therefore, CD potentially negatively affected fitness in past populations utilizing wheat, barley, and rye. Previous analyses of CD risk variants have uncovered evidence for positive selection on some of these loci. These studies also suggest the possibility that risk for common autoimmune conditions such as CD may be the result of positive selection on immune related loci in the genome to fight infection. Under this evolutionary scenario, disease phenotypes may be a trade-off from positive selection on immunity. If this hypothesis is generally true, we can expect to find a signal of natural selection when we survey across the network of loci known to influence CD risk. This study examines the non-HLA autosomal network of gene loci associated with CD risk in Europe. We reject the null hypothesis of neutrality on this network of CD risk loci. Additionally, we can localize evidence of selection in time and space by adding information from the genome of the Tyrolean Iceman. While we can show significant differentiation between continental regions across the CD network, the pattern of evidence is not consistent with primarily recent (Holocene) selection across this network in Europe. Further localization of ancient selection on this network may illuminate the ecological pressures acting on the immune system during this critically interesting phase of our evolution.

  4. The molecular through ecological genetics of abnormal abdomen in Drosophila mercatorum. V. Female phenotypic expression on natural genetic backgrounds and in natural environments.

    PubMed

    Templeton, A R; Hollocher, H; Johnston, J S

    1993-06-01

    The abnormal abdomen (aa) syndrome in Drosophila mercatorum depends on the presence of R1 inserts in a third or more of the X-linked 28S rDNA genes and the absence of selective underreplication of inserted repeats in polytene tissues that is controlled by an X-linked locus (ur) half a map unit from the rDNA complex. This syndrome affects both life history and morphology in the laboratory. Because abnormal morphologies are rarely encountered in nature, the purpose of this study is to see if the female life history traits are still affected under more natural genetic backgrounds and environmental conditions. Two outbred stocks were extracted from the natural population living near Kamuela, Hawaii: KaaX that has only X chromosomes with uraa alleles, and K+X that has only ur+ alleles. These two stocks have nonoverlapping distributions of insert proportions, indicating strong disequilibrium between the ur locus and the rDNA complex. The KaaX stock had almost no morphological penetrance of uraa, indicating that genetic background is important. KaaX expressed longer female egg-to-adult developmental times, increased early adult female fecundity, and decreased female adult longevity compared with K+X. By bagging natural rots of the cactus Opuntia megacantha near Kamuela, Hawaii, it was shown that egg-to-adult developmental time is slowed down by 0.92 days in females bearing uraa alleles in nature, with no detectable slowdown in uraa males. The bagged rot data also indicate that females bearing uraa alleles have a strong fecundity advantage in nature under some ecological conditions but not others.

  5. Natural background levels and threshold values of chemical species in three large-scale groundwater bodies in Northern Italy.

    PubMed

    Molinari, Antonio; Guadagnini, Laura; Marcaccio, Marco; Guadagnini, Alberto

    2012-05-15

    We analyze natural background levels (NBLs) and threshold values (TVs) of spatially distributed chemical species (NH(4), B and As) which may be a potential pressure and concern in three large scale alluvial and fluvio-deltaic aquifers at different depths of the Apennines and Po river plains in Emilia-Romagna, Northern Italy. Our results are based on statistical methodologies designed to separate the natural and anthropogenic contributions in monitored concentrations by modeling the empirical distribution of the detected concentration with a mixture of probability density functions. Available chemical observations are taken over a 20 years period and are associated with different depths and cover planar investigation scales of the order of hundreds of kilometers. High concentration values detected for NH(4) and B appear to be related to high natural background levels. Due to interaction with the host rock in different geochemical environments we observed that concentration vary in time and space (including in depth) consistently with the hydrogeochemical features and the occurrence of natural attenuation mechanisms in the analyzed reservoirs. Conversely, estimated As NBLs are not consistent with the conceptual model of the hydrogeochemical behavior of the systems analyzed and experimental evidences of As content in aquifer cores. This is due to the inability of these techniques to incorporate the complex dynamics of the processes associated with the specific hydrogeochemical setting. Statistical analyses performed upon aggregating the concentration data according to different time observation windows allow identifying temporal dynamics of NBLs and TVs of target compounds within the observation time frame. Our results highlight the benefit of a dynamic monitoring process and analysis of well demarcated groundwater bodies to update the associated NBLs as a function of the temporal dependence of natural processes occurring in the subsurface. Monitoring protocols could

  6. BiTS: a biologically-inspired target screener for detecting manmade objects in natural clutter backgrounds

    NASA Astrophysics Data System (ADS)

    Carlotto, Mark J.

    2010-04-01

    Motivated by biologically-inspired architectures for video analysis and object recognition, a new single band electro-optical (EO) object detector is described for aerial reconnaissance and surveillance applications. Our bio-inspired target screener (BiTS) uses a bank of Gabor filters to compute a vector of texture features over a range of scales and orientations. The filters are designed to exploit the spatial anisotropy of manmade objects relative to the background. The background, which is assumed to be predominantly natural clutter, is modeled by its global mean and covariance. The Mahalanobis distance measures deviations from the background model on a pixel-by-pixel basis. Possible manmade objects occur at peaks in the distance image. We measured the performance of BiTS on a set of 100 ground-truthed images taken under different operating conditions (resolution, sensor geometry, object spacings, background clutter, etc.) and found its probability of detection (PD) was 12% higher than a RX anomaly detector, with half the number of false alarms at a PD of 80%.

  7. Bioeconomic Approaches to Sustainable Management of Natural Tropical Forests

    Treesearch

    Tom Holmes; Erin O. Sills

    2016-01-01

    Bioeconomic models are idealized representations of human-nature interactions used to describe how the decisions that people make regarding the harvest of biological resources affect the future condition of resource stocks and the flow of net economic benefits. This modeling approach posits an assumed goal or objective that a decision-maker seeks to optimize subject to...

  8. Quality assurance of temporal variability of natural decay chain and neutron induced background for low-level NORM analysis

    SciTech Connect

    Yoho, Michael; Porterfield, Donivan R.; Landsberger, Sheldon

    2015-09-22

    In this study, twenty-one high purity germanium (HPGe) background spectra were collected over 2 years at Los Alamos National Laboratory. A quality assurance methodology was developed to monitor spectral background levels from thermal and fast neutron flux levels and naturally occurring radioactive material decay series radionuclides. 238U decay products above 222Rn demonstrated minimal temporal variability beyond that expected from counting statistics. 238U and 232Th progeny below Rn gas displayed at most twice the expected variability. Further, an analysis of the 139 keV 74Ge(n, γ) and 691 keV 72Ge(n, n') spectral features demonstrated temporal stability for both thermal and fast neutron fluxes.

  9. Quality assurance of temporal variability of natural decay chain and neutron induced background for low-level NORM analysis

    DOE PAGES

    Yoho, Michael; Porterfield, Donivan R.; Landsberger, Sheldon

    2015-09-22

    In this study, twenty-one high purity germanium (HPGe) background spectra were collected over 2 years at Los Alamos National Laboratory. A quality assurance methodology was developed to monitor spectral background levels from thermal and fast neutron flux levels and naturally occurring radioactive material decay series radionuclides. 238U decay products above 222Rn demonstrated minimal temporal variability beyond that expected from counting statistics. 238U and 232Th progeny below Rn gas displayed at most twice the expected variability. Further, an analysis of the 139 keV 74Ge(n, γ) and 691 keV 72Ge(n, n') spectral features demonstrated temporal stability for both thermal and fast neutronmore » fluxes.« less

  10. Beryllium natural background concentration and mobility: a reappraisal examining the case of high Be-bearing pyroclastic rocks.

    PubMed

    Armiento, Giovanna; Bellatreccia, Fabio; Cremisini, Carlo; Della Ventura, Giancarlo; Nardi, Elisa; Pacifico, Renata

    2013-01-01

    Beryllium is widely distributed in soils at low levels, but it can also occur naturally in higher concentrations in a variety of materials exploited for many industrial applications. Beryllium is also one of the most toxic natural elements and is known to be a human carcinogen. A concise account of the literature data on baseline concentrations of Be in soils illustrates the possibility of worldwide presence of areas with a high natural background concentration of Be (up to 300 mg/kg), the crustal abundance of which is generally estimated to be in the range 2-6 mg/kg. Nevertheless, the number of available data is rather limited in comparison with those about other toxic elements such as Pb, Cd and Cr. This has probably caused the choice of low values of concentration level as the reference for the definition of soil contamination: these values are not always realistic and are not applicable to large areas. As a case study, we report and analyse a diffuse, unusually high (up to 80 mg/kg, average approximately 20 mg/kg), natural occurrence of beryllium in loose and poorly consolidated pyroclastic layers related to the Pleistocene activity of the Vico volcano. Additionally, the analysis of Be leachability has been carried out, providing evidence of a not negligible mobility in contrast with the scarce data presented in the literature that usually indicate beryllium as an element with low mobility in oxidising surface environmental conditions. This research marks the beginning of a possible reappraisal of beryllium geochemical behaviour and background levels, providing more realistic reference values for risk assessment and land management.

  11. Toxicological assessment of kretek cigarettes: Part 1: background, assessment approach, and summary of findings.

    PubMed

    Roemer, E; Dempsey, R; Schorp, M K

    2014-12-01

    This publication introduces a series of six other publications describing the toxicological assessment of kretek cigarettes, i.e., cigarettes characterized primarily by the use of a significant amount of cloves as an ingredient added to the tobacco. This paper presents background information on kretek cigarettes, describes the general approach of the in vitro and in vivo toxicological assessment of mainstream smoke from kretek cigarettes, presents the methodology used, and summarizes the results of the assessment program. In summary, the smoke from kretek cigarettes gives rise to the typical cigarette smoke-related effects known from American-blended cigarettes, does not reveal any novel toxicity, and exhibits an unexpected distinct attenuation of pulmonary inflammation. Based on equal amounts of smoke total particulate matter (TPM), kretek cigarettes deliver less toxicants when compared to American-blended cigarettes; when assessed in vitro, the smoke from kretek cigarettes is less cytotoxic (gas/vapor phase) and less mutagenic (TPM). When assessed in vivo, kretek cigarette smoke shows lower toxicity in the respiratory tract. When based on an equal nicotine basis, several of the toxicity endpoints in kretek cigarettes become equivalent to American-blended cigarettes. The data do not indicate an increased hazard potential of kreteks compared to American-blended cigarettes. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. Wind profiling for a coherent wind Doppler lidar by an auto-adaptive background subtraction approach.

    PubMed

    Wu, Yanwei; Guo, Pan; Chen, Siying; Chen, He; Zhang, Yinchao

    2017-04-01

    Auto-adaptive background subtraction (AABS) is proposed as a denoising method for data processing of the coherent Doppler lidar (CDL). The method is proposed specifically for a low-signal-to-noise-ratio regime, in which the drifting power spectral density of CDL data occurs. Unlike the periodogram maximum (PM) and adaptive iteratively reweighted penalized least squares (airPLS), the proposed method presents reliable peaks and is thus advantageous in identifying peak locations. According to the analysis results of simulated and actually measured data, the proposed method outperforms the airPLS method and the PM algorithm in the furthest detectable range. The proposed method improves the detection range approximately up to 16.7% and 40% when compared to the airPLS method and the PM method, respectively. It also has smaller mean wind velocity and standard error values than the airPLS and PM methods. The AABS approach improves the quality of Doppler shift estimates and can be applied to obtain the whole wind profiling by the CDL.

  13. An Activist Approach to Sport Meets Youth From Socially Vulnerable Backgrounds: Possible Learning Aspirations.

    PubMed

    Luguetti, Carla; Oliver, Kimberly L; Dantas, Luiz Eduardo Pinto Basto Tourinho; Kirk, David

    2017-03-01

    This study was a 2-phase activist research project aimed at co-creating a prototype pedagogical model for working with youth from socially vulnerable backgrounds in a sport context. This article addresses the learning aspirations (learning outcomes) that emerged when we created spaces for youth to develop strategies to manage the risks they face in their community. This study took place in a socially and economically disadvantaged neighborhood in a Brazilian city where we worked with a group of 17 boys aged 13 to 15 years old, 4 coaches, a pedagogic coordinator, and a social worker. During a 6-month period, we collected multiple sources of data including field journal entries/observations (38) and audio records of youth work sessions (18), coaches' work sessions (16), combined coaches and youth work sessions (3), and meetings between the lead and the 2nd author for debriefing and planning sessions (36). By using an activist approach, 4 learning aspirations emerged: becoming responsible/committed, learning from mistakes, valuing each other's knowledge, and communicating with others. Findings suggest there is a need for more sports programs that start from young people's concrete needs and life situations and look to create places for youth to see alternative possibilities and take action.

  14. Drug development from natural resource: a systematic approach.

    PubMed

    Sharma, S B; Gupta, Richa

    2015-01-01

    Modern research in drug discovery from medicinal plants involves a multidimensional approach combining botanical, phytochemical, biochemical combinatorial chemistry and bioassay-guided fractionation approaches. Natural sources continue to provide an alternative as pharmacological leads against various devastating diseases such as diabetes, CVD, cancer etc. Nowadays, there is enormous requirement of safe and effective drugs in the world. This has prompted scientists to revert back towards natural resources as a potential source of therapeutics for treatment and management of such chronic and fatal diseases. However, there are certain serious challenges and limitations in this field including scale up and commercialization of active compounds which allow only one in thousand lead molecules to be developed as drug. A systematic and scientific approach is an essential requirement for drug development from natural resource. This mini review provides an overview of the methods involved in natural product research starting from crude plant extract to bioactive pharmacological lead. Moreover, it also discusses the limitations of working concerning the bioactivity of medicinal plants.

  15. Multiple factors impact the contents of heavy metals in vegetables in high natural background area of China.

    PubMed

    Gan, Yandong; Wang, Lihong; Yang, Guiqiang; Dai, Jiulan; Wang, Renqing; Wang, Wenxing

    2017-10-01

    A field survey was conducted to investigate the concentrations of chromium (Cr), nickel (Ni), copper (Cu), zinc (Zn), cadmium (Cd) and lead (Pb) in vegetables, corresponding cultivated soils and irrigation waters from 36 open sites in high natural background area of Wuzhou, South China. Redundancy analysis, Spearman's rho correlation analysis and multiple regression analysis were adopted to evaluate the contributions of impacting factors on metal contents in the edible parts of vegetables. This study concluded that leafy and root vegetables had relatively higher metal concentrations and adjusted transfer factor values compared to fruiting vegetables according to nonparametric tests. Plant species, total soil metal content and soil pH value were affirmed as three critical factors with the highest contribution rate among all the influencing factors. The bivariate curve equation models for heavy metals in the edible vegetable tissues were well fitted to predict the metal concentrations in vegetables. The results from this case study also suggested that it could be one of efficient strategies for clean agricultural production and food safety in high natural background area to breed vegetable varieties with low heavy metal accumulation and to enlarge planting scale of these varieties. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. The proportion of childhood leukaemia incidence in Great Britain that may be caused by natural background ionizing radiation.

    PubMed

    Wakeford, R; Kendall, G M; Little, M P

    2009-04-01

    The aetiology of childhood leukaemia remains generally unknown, although exposure to moderate and high levels of ionizing radiation, such as those experienced during the atomic bombings of Japan or from radiotherapy, is an established cause. Risk models based primarily on studies of the Japanese atomic bomb survivors imply that low-level exposure to ionizing radiation, including ubiquitous natural background radiation, also raises the risk of childhood leukaemia. Using two sets of recently published leukaemia risk models and estimates of natural background radiation red-bone-marrow doses received by children, about 20% of the cases of childhood leukaemia in Great Britain are predicted to be attributable to this source. However, for one of these sets of risk models this attributable fraction is materially dependent on how the radiation-induced risk is assumed to be transferred between the Japanese atomic bomb survivors and Western children. Over a range of annual doses representing the range (0.5-2.5 mSv/year) experienced by most populations, the attributable proportion for the preferred risk-transfer model varies between 8 and 30%, with small deviations from a linear relationship that are largely due to the saturation of the model, although again this range of attributable fractions depends on the assumed transfer of risk between populations.

  17. Capitalizing on nature: how to implement an ecosystem approach.

    PubMed

    Holt, Alison R; Hattam, Caroline

    2009-10-23

    The Natural Capital Initiative (www.naturalcapitalinitiative.org.uk) held its first conference 'Valuing our life support systems' at Savoy Place, London, from 29 April to 1 May 2009. The aim of the conference was to discuss different perspectives on, and solutions to, the conservation and sustainable use of ecosystem services. It particularly focused on the link between the environment and the economy, and how to implement an ecosystem approach to environmental management. This event brought together scientists across the natural and social sciences, alongside representatives from government, non-governmental organizations, business and industry.

  18. Effects of reduced natural background radiation on Drosophila melanogaster growth and development as revealed by the FLYINGLOW program.

    PubMed

    Morciano, Patrizia; Iorio, Roberto; Iovino, Daniela; Cipressa, Francesca; Esposito, Giuseppe; Porrazzo, Antonella; Satta, Luigi; Alesse, Edoardo; Tabocchini, Maria Antonella; Cenci, Giovanni

    2018-01-01

    Natural background radiation of Earth and cosmic rays played a relevant role during the evolution of living organisms. However, how chronic low doses of radiation can affect biological processes is still unclear. Previous data have indicated that cells grown at the Gran Sasso Underground Laboratory (LNGS, L'Aquila) of National Institute of Nuclear Physics (INFN) of Italy, where the dose rate of cosmic rays and neutrons is significantly reduced with respect to the external environment, elicited an impaired response against endogenous damage as compared to cells grown outside LNGS. This suggests that environmental radiation contributes to the development of defense mechanisms at cellular level. To further understand how environmental radiation affects metabolism of living organisms, we have recently launched the FLYINGLOW program that aims at exploiting Drosophila melanogaster as a model for evaluating the effects of low doses/dose rates of radiation at the organismal level. Here, we will present a comparative data set on lifespan, motility and fertility from different Drosophila strains grown in parallel at LNGS and in a reference laboratory at the University of L'Aquila. Our data suggest the reduced radiation environment can influence Drosophila development and, depending on the genetic background, may affect viability for several generations even when flies are moved back to normal background radiation. As flies are considered a valuable model for human biology, our results might shed some light on understanding the effect of low dose radiation also in humans. © 2017 Wiley Periodicals, Inc.

  19. Pharmacokinetic Modeling of Manganese III. Physiological Approaches Accounting for Background and Tracer Kinetics

    SciTech Connect

    Teeguarden, Justin G.; Gearhart, Jeffrey; Clewell, III, H. J.; Covington, Tammie R.; Nong, Andy; Anderson, Melvin E.

    2007-01-01

    Manganese (Mn) is an essential nutrient. Mn deficiency is associated with altered lipid (Kawano et al. 1987) and carbohydrate metabolism (Baly et al. 1984; Baly et al. 1985), abnormal skeletal cartilage development (Keen et al. 2000), decreased reproductive capacity, and brain dysfunction. Occupational and accidental inhalation exposures to aerosols containing high concentrations of Mn produce neurological symptoms with Parkinson-like characteristics in workers. At present, there is also concern about use of the manganese-containing compound, methylcyclopentadienyl manganese tricarbonyl (MMT), in unleaded gasoline as an octane enhancer. Combustion of MMT produces aerosols containing a mixture of manganese salts (Lynam et al. 1999). These Mn particulates may be inhaled at low concentrations by the general public in areas using MMT. Risk assessments for essential elements need to acknowledge that risks occur with either excesses or deficiencies and the presence of significant amounts of these nutrients in the body even in the absence of any exogenous exposures. With Mn there is an added complication, i.e., the primary risk is associated with inhalation while Mn is an essential dietary nutrient. Exposure standards for inhaled Mn will need to consider the substantial background uptake from normal ingestion. Andersen et al. (1999) suggested a generic approach for essential nutrient risk assessment. An acceptable exposure limit could be based on some ‘tolerable’ change in tissue concentration in normal and exposed individuals, i.e., a change somewhere from 10 to 25 % of the individual variation in tissue concentration seen in a large human population. A reliable multi-route, multi-species pharmacokinetic model would be necessary for the implementation of this type of dosimetry-based risk assessment approach for Mn. Physiologically-based pharmacokinetic (PBPK) models for various xenobiotics have proven valuable in contributing to a variety of chemical specific risk

  20. Anaerobic digestion for sustainable development: a natural approach.

    PubMed

    Gljzen, H J

    2002-01-01

    After the discovery of methane gas by Alessandro Volta in 1776, it took about 100 years before anaerobic processes for the treatment of wastewater and sludges were introduced. The development of high rate anaerobic digesters for the treatment of sewage and industrial wastewater took until the nineteen-seventies and for solid waste even till the nineteen-eighties. All digesters have in common that they apply natural anaerobic consortia of microorganisms for degradation and transformation processes. In view of this, it could be rewarding to evaluate the efficiency of natural ecosystems for their possible application. Examples of high rate anaerobic natural systems include the forestomach of ruminants and the hindgut of certain insects, such as termites and cockroaches. These 'natural reactors' exhibit volumetric methane production rates as high as 35 l/l.d. The development of anaerobic reactors based on such natural anaerobic systems could produce eco-technologies for the effective management of a wide variety of solid wastes and industrial wastewater. Important limitations of anaerobic treatment of domestic sewage relate to the absence of nutrient and pathogen removal. A combination of anaerobic pre-treatment followed by photosynthetic posttreatment is proposed for the effective recovery of energy and nutrients from sewage. This eco-technology approach is based on the recognition that the main nutrient assimilating capacity is housed in photosynthetic plants. The proposed anaerobic-photosynthetic process is energy efficient, cost effective and applicable under a wide variety of rural and urban conditions. a natural systems approach towards waste management could generate affordable eco-technologies for effective treatment and resource recovery.

  1. Learning from nature - novel synthetic biology approaches for biomaterial design.

    PubMed

    Bryksin, Anton V; Brown, Ashley C; Baksh, Michael M; Finn, M G; Barker, Thomas H

    2014-04-01

    Many biomaterials constructed today are complex chemical structures that incorporate biologically active components derived from nature, but the field can still be said to be in its infancy. The need for materials that bring sophisticated properties of structure, dynamics and function to medical and non-medical applications will only grow. Increasing appreciation of the functionality of biological systems has caused biomaterials researchers to consider nature for design inspiration, and many examples exist of the use of biomolecular motifs. Yet evolution, nature's only engine for the creation of new designs, has been largely ignored by the biomaterials community. Molecular evolution is an emerging tool that enables one to apply nature's engineering principles to non-natural situations using variation and selection. The purpose of this review is to highlight the most recent advances in the use of molecular evolution in synthetic biology applications for biomaterial engineering, and to discuss some of the areas in which this approach may be successfully applied in the future. Copyright © 2014 Acta Materialia Inc. All rights reserved.

  2. A Coupled Human-Natural Systems Approach to Valuing Natural Capital

    NASA Astrophysics Data System (ADS)

    Fenichel, E. P.; Abbott, J.; Fujitani, M.

    2012-12-01

    The idea that geological and biological natural resources provide ecosystem services and that the physical geological and biological stocks, referred to as ecological stocks, are forms of capital is not new, but has attracted increased attention since the Millennium Ecosystem Assessment was released in 2005. Yet, the exact meaning of these terms, the connection between natural capital and ecosystem services, and the broader links between biophysical science and economics is often vague. The conceptual connection between ecosystem services and natural capital is that ecosystem services are the flow of goods and services that people receive from natural resources, and these flows are generated by an endowment of ecological stocks. While individuals derive benefits from a flow of services, the extent that people value the underlying natural capital asset depends on institutional arrangements in addition to the ecological properties of the stocks, because the value of capital relates to the future flow of services. A coupled human-natural systems modeling approach can help understand the value of natural capital in addition to helping scientist and policy makers better manage earth's resources. The value of a capital asset is the net present value of the flow of service, often calculated by the NPV rule. The NPV rule almost always assumes perfectly functioning markets for services and capital, but for many important ecosystem services such markets simply do not exist. The NPV rule can be derived by maximizing the net present value of capital. Indeed, the NPV rule comes from the adjoint condition of an optimal control problem where the flow of services from the capital asset are the benefits, and the dynamics of the capital stock are the constraints. Yet, trying to apply the traditional NPV rule to ecosystem services and natural capital can be frustrated by not knowing where pieces of the puzzle fit. We compare the standard NPV rule with a modified NPV rule derived by

  3. 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.

  4. The interaction of natural background gamma radiation with depleted uranium micro-particles in the human body.

    PubMed

    Pattison, John E

    2013-03-01

    In this study, some characteristics of the photo-electrons produced when natural background gamma radiation interacts with micron-sized depleted uranium (DU) particles in the human body have been estimated using Monte Carlo simulations. In addition, an estimate has been made of the likelihood of radiological health effects occurring due to such an exposure. Upon exposure to naturally occurring background gamma radiation, DU particles in the body will produce an enhancement of the dose to the tissue in the immediate vicinity of the particles due to the photo-electric absorption of the radiation in the particle. In this study, the photo-electrons produced by a 10 μm-size particle embedded in tissue at the centre of the human torso have been investigated. The mean energies of the photo-electrons in the DU particle and in the two consecutive immediately surrounding 2 μm-wide tissue shells around the particle were found to be 38, 49 and 50 keV, respectively, with corresponding ranges of 1.3, 38 and 39 μm, respectively. The total photo-electron fluence-rates in the two consecutive 2 μm-wide tissue layers were found to be 14% and 7% of the fluence-rate in the DU particle, respectively. The estimated dose enhancement due to one 10 μm-sized DU particle in 1 cm(3) of tissue was less than 2 in 10 million of the dose received by the tissue without a particle being present. The increase in risk of death from cancer due to this effect is consequently insignificant.

  5. Inhibitory effect of natural organic matter or other background constituents on photocatalytic advanced oxidation processes: Mechanistic model development and validation.

    PubMed

    Brame, Jonathon; Long, Mingce; Li, Qilin; Alvarez, Pedro

    2015-11-01

    The ability of reactive oxygen species (ROS) to interact with priority pollutants is crucial for efficient water treatment by photocatalytic advanced oxidation processes (AOPs). However, background compounds in water such as natural organic matter (NOM) can significantly hinder targeted reactions and removal efficiency. This inhibition can be complex, interfering with degradation in solution and at the photocatalyst surface as well as hindering illumination efficiency and ROS production. We developed an analytical model to account for various inhibition mechanisms in catalytic AOPs, including competitive adsorption of inhibitors, scavenging of produced ROS at the surface and in solution, and the inner filtering of the excitation illumination, which combine to decrease ROS-mediated degradation. This model was validated with batch experiments using a variety of ROS producing systems (OH-generating TiO2 photocatalyst and H2O2-UV; (1)O2-generating photosensitive functionalized fullerenes and rose bengal) and inhibitory compounds (NOM, tert-butyl alcohol). Competitive adsorption by NOM and ROS scavenging were the most influential inhibitory mechanisms. Overall, this model enables accurate simulation of photocatalytic AOP performance when one or more inhibitory mechanisms are at work in a wide variety of application scenarios, and underscores the need to consider the effects of background constituents on degradation efficiency.

  6. Resolving structural uncertainty in natural resources management using POMDP approaches

    USGS Publications Warehouse

    Williams, B.K.

    2011-01-01

    In recent years there has been a growing focus on the uncertainties of natural resources management, and the importance of accounting for uncertainty in assessing management effectiveness. This paper focuses on uncertainty in resource management in terms of discrete-state Markov decision processes (MDP) under structural uncertainty and partial observability. It describes the treatment of structural uncertainty with approaches developed for partially observable resource systems. In particular, I show how value iteration for partially observable MDPs (POMDP) can be extended to structurally uncertain MDPs. A key difference between these process classes is that structurally uncertain MDPs require the tracking of system state as well as a probability structure for the structure uncertainty, whereas with POMDPs require only a probability structure for the observation uncertainty. The added complexity of the optimization problem under structural uncertainty is compensated by reduced dimensionality in the search for optimal strategy. A solution algorithm for structurally uncertain processes is outlined for a simple example in conservation biology. By building on the conceptual framework developed for POMDPs, natural resource analysts and decision makers who confront structural uncertainties in natural resources can take advantage of the rapid growth in POMDP methods and approaches, and thereby produce better conservation strategies over a larger class of resource problems. ?? 2011.

  7. Programmatic background, site description, experimental approach and treatment, and natural disturbances

    Treesearch

    Wayne T. Swank; Jackson Webster

    2014-01-01

    This volume is a synthesis of a long-term interdisciplinary study of watershed ecosystem responses to a forest-management disturbance. Specifically, a commercial clearcut cable logging experiment was initiated on Watershed 7 (WS 7) at the Coweeta Hydrologic Laboratory in 1975 to elucidate ecosystem structure and function by testing hypotheses associated with the...

  8. Macondo oil in deep-sea sediments: Part 2 - Distribution and distinction from background and natural oil seeps.

    PubMed

    Stout, Scott A; Payne, James R; Ricker, Robert W; Baker, Gregory; Lewis, Christopher

    2016-10-15

    Following the Deepwater Horizon oil spill, the spilled Macondo oil was severely weathered during its transport within the deep-sea plume as discrete particles, which were subsequently deposited on the seafloor. The Macondo oil deposited in deep-sea sediments was distinguished from ambient (background) hydrocarbons and naturally-seeped and genetically-similar oils in the Mississippi Canyon region using a forensic method based upon a systematic, multi-year study of 724 deep-sea sediment cores collected in late 2010 and 2011. The method relied upon: (1) chemical fingerprinting of the distinct features of the wax-rich, severely-weathered Macondo oil; (2) hydrocarbon concentrations, considering a core's proximity to the Macondo well or to known or apparent natural oil seeps, and also vertically within a core; and (3) results from proximal cores and flocculent material from core supernatants and slurp gun filters. The results presented herein establish the geographic extent of "fingerprintable" Macondo oil recognized on the seafloor in 2010/2011.

  9. The analysis on the extreme water shortage event in Hangzhou in 1247 AD and its natural and social backgrounds

    NASA Astrophysics Data System (ADS)

    Liu, Haolong

    2017-04-01

    Yangtze River Delta locating in the north subtropics of China, is famous for numerous rivers and lakes. Because of East Asian monsoon rainfall, flood is always the most primary disaster in this area during the past 2000 years. However, there were also several extreme water shortage events in the history. Example in Hangzhou in 1247 AD was such a typical year in the area. In the paper, the severity of this extreme event and the closely tied spatiotemporal variation of drought in Yangtze River Delta was quantitatively analyzed on the basis of documentary records during Southern Song Dynasty. Furtherly, its natural and social backgrounds was discussed. The result s are summarized as follows: 1) Wells, canals and West Lake of Hangzhou dried up in 1247 AD. The water level of canals was about 1.32-2.64 m lower than that in the normal year. The reduction of storage capacity in West Lake was 21 million stere or so. 2) The droughts in Yangtze River Delta was moderate on the whole, but that in the west of Zhejiang Province was severe. The drought in Hangzhou lasted from the 2nd lunar month to the end of this year. 3) The water shortage event was closely related to the quick going north and farther northern location of summer rain belt. The descending sea-level weakening the tide in Qiantang River, can also reduce the supply of water resources. 4) The quick growth of urban population, excessive aquaculture, and ineffective government supervision played an important social role in the process of this event. In the all, this extreme water shortage event was the result of both natural and social factors. This research is very helpful for the futuristic water resource forecast in Yangtze River Delta, and it also affords us lessons on the risk management and heritage conservation that merit attention. Key Words: Hangzhou, 1247 AD, water shortage, canal, West Lake, natural factors, social factors

  10. Rationale for a natural products approach to herbicide discovery.

    PubMed

    Dayan, Franck E; Owens, Daniel K; Duke, Stephen O

    2012-04-01

    Weeds continue to evolve resistance to all the known modes of herbicidal action, but no herbicide with a new target site has been commercialized in nearly 20 years. The so-called 'new chemistries' are simply molecules belonging to new chemical classes that have the same mechanisms of action as older herbicides (e.g. the protoporphyrinogen-oxidase-inhibiting pyrimidinedione saflufenacil or the very-long-chain fatty acid elongase targeting sulfonylisoxazoline herbicide pyroxasulfone). Therefore, the number of tools to manage weeds, and in particular those that can control herbicide-resistant weeds, is diminishing rapidly. There is an imminent need for truly innovative classes of herbicides that explore chemical spaces and interact with target sites not previously exploited by older active ingredients. This review proposes a rationale for a natural-products-centered approach to herbicide discovery that capitalizes on the structural diversity and ingenuity afforded by these biologically active compounds. The natural process of extended-throughput screening (high number of compounds tested on many potential target sites over long periods of times) that has shaped the evolution of natural products tends to generate molecules tailored to interact with specific target sites. As this review shows, there is generally little overlap between the mode of action of natural and synthetic phytotoxins, and more emphasis should be placed on applying methods that have proved beneficial to the pharmaceutical industry to solve problems in the agrochemical industry.

  11. A Systematic Approach to Discover and Characterize Natural Plant Biostimulants

    PubMed Central

    Povero, Giovanni; Mejia, Juan F.; Di Tommaso, Donata; Piaggesi, Alberto; Warrior, Prem

    2016-01-01

    The use of natural plant biostimulants is proposed as an innovative solution to address the challenges to sustainable agriculture, to ensure optimal nutrient uptake, crop yield, quality, and tolerance to abiotic stress. However, the process of selection and characterization of plant biostimulant matrices is complex and involves a series of rigorous evaluations customized to the needs of the plant. Here, we propose a highly differentiated plant biostimulant development and production platform, which involves a combination of technology, processes, and know-how. Chemistry, biology and omic concepts are combined/integrated to investigate and understand the specific mode(s) of action of bioactive ingredients. The proposed approach allows to predict and characterize the function of natural compounds as biostimulants. By managing and analyzing massive amounts of complex data, it is therefore possible to discover, evaluate and validate new product candidates, thus expanding the uses of existing products to meet the emerging needs of agriculture. PMID:27092156

  12. LUCIFER, a potentially background-free approach to the search for neutrinoless double beta decay

    NASA Astrophysics Data System (ADS)

    Nones, C.; Lucifer Group

    2011-08-01

    LUCIFER (Low-background Underground Cryogenic Installation For Elusive Rates) is a new project for the study of neutrinoless Double Beta Decay, based on the technology of scintillating bolometers. These devices promise a very efficient rejection of the alpha background, opening the way to a virtual background-free experiment if candidates with a transition energy higher than 2615 keV are investigated. The baseline candidate for LUCIFER is 82Se. This isotope will be embedded in ZnSe crystals grown with enriched selenium and operated as scintillating bolometers in a low-radioactivity underground dilution refrigerator. In this paper, the LUCIFER concept will be introduced. The sensitivity and the very promising prospects related to this project will be discussed.

  13. Approaches to metal speciation analysis in natural waters

    NASA Astrophysics Data System (ADS)

    Morrison, G. M. P.

    Approaches to the separation and identification of metal species in natural waters are discussed. Dissolved and colloidal metal species may be fractionated, on the basis of physico-chemical characteristics, by ion exchange, u.v. irradiation, resin adsorption, solvent extraction or strong acid digestion. Size fractionation techniques include filtration, centrifugation, dialysis, ultrafiltration and gel filtration chromatography. Suitable detection techniques, either before or after fractionation, are anodic stripping voltammetry, ion selective electrodes and atomic absorption. The bioavailable uptake rate of metal species may be determined by Dialysis with Receiving Resins.

  14. Local participation in natural resource monitoring: a characterization of approaches.

    PubMed

    Danielsen, Finn; Burgess, Neil D; Balmford, Andrew; Donald, Paul F; Funder, Mikkel; Jones, Julia P G; Alviola, Philip; Balete, Danilo S; Blomley, Tom; Brashares, Justin; Child, Brian; Enghoff, Martin; Fjeldså, Jon; Holt, Sune; Hübertz, Hanne; Jensen, Arne E; Jensen, Per M; Massao, John; Mendoza, Marlynn M; Ngaga, Yonika; Poulsen, Michael K; Rueda, Ricardo; Sam, Moses; Skielboe, Thomas; Stuart-Hill, Greg; Topp-Jørgensen, Elmer; Yonten, Deki

    2009-02-01

    The monitoring of trends in the status of species or habitats is routine in developed countries, where it is funded by the state or large nongovernmental organizations and often involves large numbers of skilled amateur volunteers. Far less monitoring of natural resources takes place in developing countries, where state agencies have small budgets, there are fewer skilled professionals or amateurs, and socioeconomic conditions prevent development of a culture of volunteerism. The resulting lack of knowledge about trends in species and habitats presents a serious challenge for detecting, understanding, and reversing declines in natural resource values. International environmental agreements require signatories undertake systematic monitoring of their natural resources, but no system exists to guide the development and expansion of monitoring schemes. To help develop such a protocol, we suggest a typology of monitoring categories, defined by their degree of local participation, ranging from no local involvement with monitoring undertaken by professional researchers to an entirely local effort with monitoring undertaken by local people. We assessed the strengths and weaknesses of each monitoring category and the potential of each to be sustainable in developed or developing countries. Locally based monitoring is particularly relevant in developing countries, where it can lead to rapid decisions to solve the key threats affecting natural resources, can empower local communities to better manage their resources, and can refine sustainable-use strategies to improve local livelihoods. Nevertheless, we recognize that the accuracy and precision of the monitoring undertaken by local communities in different situations needs further study and field protocols need to be further developed to get the best from the unrealized potential of this approach. A challenge to conservation biologists is to identify and establish the monitoring system most relevant to a particular

  15. Activating Student Background Knowledge in a Take Charge Approach to Foreign Language Reading.

    ERIC Educational Resources Information Center

    Young, Dolly J.

    1991-01-01

    Addresses the immediate needs of language teachers who want to develop their students' reading skills but have not been provided with the instructional information necessary to do so. It suggests a methodological sequence for using the students' background knowledge and strategy training for foreign language reading using authentic texts. (33…

  16. An Activist Approach to Sport Meets Youth from Socially Vulnerable Backgrounds: Possible Learning Aspirations

    ERIC Educational Resources Information Center

    Luguetti, Carla; Oliver, Kimberly L.; Dantas, Luiz Eduardo Pinto Basto Tourinho; Kirk, David

    2017-01-01

    Purpose: This study was a 2-phase activist research project aimed at co-creating a prototype pedagogical model for working with youth from socially vulnerable backgrounds in a sport context. This article addresses the learning aspirations (learning outcomes) that emerged when we created spaces for youth to develop strategies to manage the risks…

  17. Preschool Teachers' Professional Background, Process Quality, and Job Attitudes: A Person-Centered Approach

    ERIC Educational Resources Information Center

    Jeon, Lieny; Buettner, Cynthia K.; Hur, Eunhye

    2016-01-01

    Research Findings: This exploratory study identified preschool teacher quality profiles in early childhood education settings using 9 indicators across teachers' professional background, observed process quality, and job attitudes toward teaching (e.g., job-related stress, satisfaction, and intention to leave the job). The sample consisted of 96…

  18. Does a Nurturing Approach That Uses an Outdoor Play Environment Build Resilience in Children from a Challenging Background?

    ERIC Educational Resources Information Center

    McArdle, Karen; Harrison, Terri; Harrison, Daniel

    2013-01-01

    Children from challenging backgrounds were brought to a woodland for a programme that sought to promote resilience at Camphill School. This qualitative study of one programme uses an ethnographic approach to research the effectiveness of this type of intervention. Case studies of three of the children are used to illustrate the ways in which…

  19. Does a Nurturing Approach That Uses an Outdoor Play Environment Build Resilience in Children from a Challenging Background?

    ERIC Educational Resources Information Center

    McArdle, Karen; Harrison, Terri; Harrison, Daniel

    2013-01-01

    Children from challenging backgrounds were brought to a woodland for a programme that sought to promote resilience at Camphill School. This qualitative study of one programme uses an ethnographic approach to research the effectiveness of this type of intervention. Case studies of three of the children are used to illustrate the ways in which…

  20. Prevention of microbial communities: novel approaches based natural products.

    PubMed

    Mogosanu, George D; Grumezescu, Alexandru M; Huang, Keng-Shiang; Bejenaru, Ludovic E; Bejenaru, Cornelia

    2015-01-01

    Firmly attached to different living or non-living, solid or fluid surfaces rich in nutrients and moisture, microbial biofilm is a matter of great interest due to its major importance for the healthcare community. Depending on common strategies such as mutual protection and hibernation (quiescent bacteria), the resistance, survival and virulence of microbial communities have large implications for human pathology, clinical environment and biomedical devices. The microbial biofilm is continuously changing, stimulating inflammation, increasing vascular permeability and preventing the action of macrophages. About 80% of human infections affecting the gastrointestinal, genitourinary and respiratory systems, oral mucosa and teeth, eyes, middle ear and skin are caused by biofilm-associated microorganisms. Therefore, the search for modern strategies is even more important as microbial biofilms resistant to conventional antibiotics, antiseptics and disinfectants are involved in the frequent treatment failures of some chronic inflammatory diseases and wounds. Natural products containing secondary metabolites, such as aromatic compounds, sulphurated derivatives, terpenoids (essential oils) and alkaloids as quorum-sensing inhibitors and biofilm disruptors, are promising alternatives for the prophylaxis and treatment of chronic infections. Surface modification of medical devices with non-polar functionalized nanoparticles stabilizes the natural compounds antibiofilm activity and inhibits microbial adhesion and biofilm formation and growth for a longer period of time. In this regard, an interdisciplinary approach is needed due to the large number of natural derivatives alone or in combination with biocompatible and biodegradable micro-/ nano-engineered materials.

  1. Science of Integrated Approaches to Natural Resources Management

    NASA Astrophysics Data System (ADS)

    Tengberg, Anna; Valencia, Sandra

    2017-04-01

    To meet multiple environmental objectives, integrated programming is becoming increasingly important for the Global Environmental Facility (GEF), the financial mechanism of the multilateral environmental agreements, including the United Nations Convention to Combat Desertification (UNCCD). Integration of multiple environmental, social and economic objectives also contributes to the achievement of the Sustainable Development Goals (SDGs) in a timely and cost-effective way. However, integration is often not well defined. This paper therefore focuses on identifying key aspects of integration and assessing their implementation in natural resources management (NRM) projects. To that end, we draw on systems thinking literature, and carry out an analysis of a random sample of GEF integrated projects and in-depth case studies demonstrating lessons learned and good practices in addressing land degradation and other NRM challenges. We identify numerous challenges and opportunities of integrated approaches that need to be addressed in order to maximise the catalytic impact of the GEF during problem diagnosis, project design, implementation and governance. We highlight the need for projects to identify clearer system boundaries and main feedback mechanisms within those boundaries, in order to effectively address drivers of environmental change. We propose a theory of change for Integrated Natural Resources Management (INRM) projects, where short-term environmental and socio-economic benefits will first accrue at the local level. Implementation of improved INRM technologies and practices at the local level can be extended through spatial planning, strengthening of innovation systems, and financing and incentive mechanisms at the watershed and/or landscape/seascape level to sustain and enhance ecosystem services at larger scales and longer time spans. We conclude that the evolving scientific understanding of factors influencing social, technical and institutional innovations and

  2. An analytical approach to the CMB anisotropies in a spatially closed background

    NASA Astrophysics Data System (ADS)

    Niazy, Pedram; Abbassi, Amir H.

    2017-09-01

    The scalar mode temperature fluctuations of the cosmic microwave background has been derived in a spatially closed universe from two different methods. First, by following the photon trajectory after the last scattering and then from the Boltzmann equation in a closed background and the line of sight integral method. An analytic expression for the temperature multipole coefficient has been extracted at the hydrodynamical limit, where we have considered some tolerable approximations. By considering a realistic set of cosmological parameters taken from a fit to data from Planck, the TT power spectrum in the scalar mode for the closed universe has been compared with numerical one by using the CAMB code and also latest observational data. The analytic result agrees with the numerical one on almost all scales. The peak positions are in very good agreement with numerical result while the peak heights agree with that to within 10% due to the approximations have been considered for this derivation.

  3. Statistical Approach to Background Subtraction for Production of High-Quality Silhouettes for Human Gait Recognition

    DTIC Science & Technology

    2006-09-01

    and Little believe oscillations are the center of gait analysis . Thus frequency entrainment and phase locking are important in both model-free and...background scene from video containing a person walking. This data may be used in a variety of ways to perform continued gait analysis . This chapter...Jeffrey E. and James J. Little. “Phase Models in Gait Analysis ,” Exemplars versus Models Workshop Computer Vision and Pattern Recognition, Kauai, HI

  4. Combining natural background levels (NBLs) assessment with indicator kriging analysis to improve groundwater quality data interpretation and management.

    PubMed

    Ducci, Daniela; de Melo, M Teresa Condesso; Preziosi, Elisabetta; Sellerino, Mariangela; Parrone, Daniele; Ribeiro, Luis

    2016-11-01

    The natural background level (NBL) concept is revisited and combined with indicator kriging method to analyze the spatial distribution of groundwater quality within a groundwater body (GWB). The aim is to provide a methodology to easily identify areas with the same probability of exceeding a given threshold (which may be a groundwater quality criteria, standards, or recommended limits for selected properties and constituents). Three case studies with different hydrogeological settings and located in two countries (Portugal and Italy) are used to derive NBL using the preselection method and validate the proposed methodology illustrating its main advantages over conventional statistical water quality analysis. Indicator kriging analysis was used to create probability maps of the three potential groundwater contaminants. The results clearly indicate the areas within a groundwater body that are potentially contaminated because the concentrations exceed the drinking water standards or even the local NBL, and cannot be justified by geogenic origin. The combined methodology developed facilitates the management of groundwater quality because it allows for the spatial interpretation of NBL values.

  5. Subjective Measurement of Tactical Air Command and Control. Volume I. Background and Approach.

    DTIC Science & Technology

    1981-03-01

    77 09104 RAND CORP SANTA MONICA CA F/ 17/2SUBIJECTIVE MEASUREMENT OF TACTICAL AIR COMMAND AND CONTROL. VOL-ETC(U) UNL MAR 81 M CALLERO ,. NASLUNO, C...TACTICAL AIR COMMWI AND CGITOL--VOL. 1: BACKGROUND AND APPRAC Monti Callero , Willard Naslund, "-LI Clairice T. Veit March 1981 D ~MAY19. N- 1671/1-AF...ORG. REPORT NUMBER 7 AuTHOR(e) ., CONTRACT OR GRANT NUMBER(*) Monti Callero , Willard Naslund, Clairice T. Veit F49620-77-C-0023 9. PERFORMING

  6. Variations of the Hydrothermal Characteristics over the Baikal Natural Territory on the Background of Global Climate Changes

    NASA Astrophysics Data System (ADS)

    Shulgina, T. M.; Voropai, N. N.; Maksyutova, E.

    2014-12-01

    In recent decades studying of climate changes on the globe became one of the most important researches. From this point of view, Siberia is particular climatically interest region in Eurasia because of its complicated bioclimatic structure. Climatic changed observed over the region substantially contributes into global climate processes. In particular, temperature trends in the second half of the 20th century were quite high (>0.2 oC/10 yr). The aim of the present work is to estimate intensity of hydrothermal characteristics changes for 1961-2008 over the Baikal Natural Territory on the background of global climate change. Most of the area is characterized by extreme continental climate while the climate of the Baikal coast is close to the seaside. Winter temperature at the shores of Lake Baikal is 5oC higher than at the central areas, but summer air temperature is lower. The annual average temperature is negative almost at the whole area. Annual trends of air temperature are positive and ranged from 0.24 to 0,52 °C per 10 yrs. Trends for individual months are also positive. They vary from 0.33 (September) to 0.99 °C per 10 years (February). Precipitations over the territory are distributed irregularly. A highest precipitation observes within the Khamar-Daban ridge and on the windward slopes of the ridges bordering the Baikal Lake (up to 1400 mm), at the hinterland highlands (400-700 mm), and in the central part of the Transbaikal steppe (200-250 mm). Minimal amount of precipitation observes in winter, the highest in July and August. Precipitation trends are not statistically significant. The most important extreme hydrothermal phenomena occurring at the study area are droughts. Months and years were revealed when more than 60% of the territory was occupied by the drought. The highest frequency of these events was registered in the period of 1990-2008. Increased droughts intensity observed at coastal stations of the Baikal Lake in May-June, Predbajkale - in July

  7. "Bundle Data" Approach at GES DISC Targeting Natural Hazards

    NASA Astrophysics Data System (ADS)

    Shie, C. L.; Shen, S.; Kempler, S. J.

    2015-12-01

    Severe natural phenomena such as hurricane, volcano, blizzard, flood and drought have the potential to cause immeasurable property damages, great socioeconomic impact, and tragic loss of human life. From searching to assessing the "Big", i.e., massive and heterogeneous scientific data (particularly, satellite and model products) in order to investigate those natural hazards, it has, however, become a daunting task for Earth scientists and applications researchers, especially during recent decades. The NASA Goddard Earth Sciences Data and Information Service Center (GES DISC) has served "Big" Earth science data, and the pertinent valuable information and services to the aforementioned users of diverse communities for years. In order to help and guide our users to online readily (i.e., with a minimum effort) acquire their requested data from our enormous resource at GES DISC for studying their targeted hazard/event, we have thus initiated a "Bundle Data" approach in 2014, first targeting the hurricane event/topic. We have recently worked on new topics such as volcano and blizzard. The "bundle data" of a specific hazard/event is basically a sophisticated integrated data package consisting of a series of proper datasets containing a group of relevant ("knowledge-based") data variables readily accessible to users via a system-prearranged table linking those data variables to the proper datasets (URLs). This online approach has been developed by utilizing a few existing data services such as Mirador as search engine; Giovanni for visualization; and OPeNDAP for data access, etc. The online "Data Cookbook" site at GES DISC is the current host for the "bundle data". We are now also planning on developing an "Automated Virtual Collection Framework" that shall eventually accommodate the "bundle data", as well as further improve our management in "Big Data".

  8. Bundle Data Approach at GES DISC Targeting Natural Hazards

    NASA Technical Reports Server (NTRS)

    Shie, Chung-Lin; Shen, Suhung; Kempler, Steven J.

    2015-01-01

    Severe natural phenomena such as hurricane, volcano, blizzard, flood and drought have the potential to cause immeasurable property damages, great socioeconomic impact, and tragic loss of human life. From searching to assessing the Big, i.e., massive and heterogeneous scientific data (particularly, satellite and model products) in order to investigate those natural hazards, it has, however, become a daunting task for Earth scientists and applications researchers, especially during recent decades. The NASA Goddard Earth Sciences Data and Information Service Center (GES DISC) has served Big Earth science data, and the pertinent valuable information and services to the aforementioned users of diverse communities for years. In order to help and guide our users to online readily (i.e., with a minimum effort) acquire their requested data from our enormous resource at GES DISC for studying their targeted hazard event, we have thus initiated a Bundle Data approach in 2014, first targeting the hurricane event topic. We have recently worked on new topics such as volcano and blizzard. The bundle data of a specific hazard event is basically a sophisticated integrated data package consisting of a series of proper datasets containing a group of relevant (knowledge--based) data variables readily accessible to users via a system-prearranged table linking those data variables to the proper datasets (URLs). This online approach has been developed by utilizing a few existing data services such as Mirador as search engine; Giovanni for visualization; and OPeNDAP for data access, etc. The online Data Cookbook site at GES DISC is the current host for the bundle data. We are now also planning on developing an Automated Virtual Collection Framework that shall eventually accommodate the bundle data, as well as further improve our management in Big Data.

  9. Design of natural food antioxidant ingredients through a chemometric approach.

    PubMed

    Mendiola, Jose A; Martín-Alvarez, Pedro J; Señoráns, F Javier; Reglero, Guillermo; Capodicasa, Alessandro; Nazzaro, Filomena; Sada, Alfonso; Cifuentes, Alejandro; Ibáñez, Elena

    2010-01-27

    In the present work, an environmentally friendly extraction process using subcritical conditions has been tested to obtain potential natural food ingredients from natural sources such as plants, fruits, spirulina, propolis, and tuber, with the scope of substituting synthetic antioxidants, which are subject to regulation restrictions and might be harmful for human health. A full characterization has been undertaken from the chemical and biochemical point of view to be able to understand their mechanism of action. Thus, an analytical method for profiling the compounds responsible for the antioxidant activity has been used, allowing the simultaneous determination of water-soluble vitamins, fat-soluble vitamins, phenolic compounds, carotenoids, and chlorophylls in a single run. This information has been integrated and analyzed using a chemometrical approach to correlate the bioactive compounds profile with the antioxidant activity and thus to be able to predict antioxidant activities of complex formulations. As a further step, a simplex centroid mixture design has been tested to find the optimal formulation and to calculate the effect of the interaction among individual extracts in the mixture.

  10. The algebraic-hyperbolic approach to the linearized gravitational constraints on a Minkowski background

    NASA Astrophysics Data System (ADS)

    Winicour, Jeffrey

    2017-08-01

    An algebraic-hyperbolic method for solving the Hamiltonian and momentum constraints has recently been shown to be well posed for general nonlinear perturbations of the initial data for a Schwarzschild black hole. This is a new approach to solving the constraints of Einstein’s equations which does not involve elliptic equations and has potential importance for the construction of binary black hole data. In order to shed light on the underpinnings of this approach, we consider its application to obtain solutions of the constraints for linearized perturbations of Minkowski space. In that case, we find the surprising result that there are no suitable Cauchy hypersurfaces in Minkowski space for which the linearized algebraic-hyperbolic constraint problem is well posed.

  11. Does human activity impact the natural antibiotic resistance background? Abundance of antibiotic resistance genes in 21 Swiss lakes.

    PubMed

    Czekalski, Nadine; Sigdel, Radhika; Birtel, Julia; Matthews, Blake; Bürgmann, Helmut

    2015-08-01

    Antibiotic resistance genes (ARGs) are emerging environmental contaminants, known to be continuously discharged into the aquatic environment via human and animal waste. Freshwater aquatic environments represent potential reservoirs for ARG and potentially allow sewage-derived ARG to persist and spread in the environment. This may create increased opportunities for an eventual contact with, and gene transfer to, human and animal pathogens via the food chain or drinking water. However, assessment of this risk requires a better understanding of the level and variability of the natural resistance background and the extent of the human impact. We have analyzed water samples from 21 Swiss lakes, taken at sampling points that were not under the direct influence of local contamination sources and analyzed the relative abundance of ARG using quantitative real-time PCR. Copy numbers of genes mediating resistance to three different broad-spectrum antibiotic classes (sulfonamides: sul1, sul2, tetracyclines: tet(B), tet(M), tet(W) and fluoroquinolones: qnrA) were normalized to copy numbers of bacterial 16S rRNA genes. We used multiple linear regression to assess if ARG abundance is related to human activities in the catchment, microbial community composition and the eutrophication status of the lakes. Sul genes were detected in all sampled lakes, whereas only four lakes contained quantifiable numbers of tet genes, and qnrA remained below detection in all lakes. Our data indicate higher abundance of sul1 in lakes with increasing number and capacity of wastewater treatment plants (WWTPs) in the catchment. sul2 abundance was rather related to long water residence times and eutrophication status. Our study demonstrates the potential of freshwater lakes to preserve antibiotic resistance genes, and provides a reference for ARG abundance from lake systems with low human impact as a baseline for assessing ARG contamination in lake water.

  12. Proteogenomic approaches for the molecular characterization of natural microbial communities.

    PubMed

    Banfield, Jillian F; Verberkmoes, Nathan C; Hettich, Robert L; Thelen, Michael P

    2005-01-01

    At the present time we know little about how microbial communities function in their natural habitats. For example, how do microorganisms interact with each other and their physical and chemical surroundings and respond to environmental perturbations? We might begin to answer these questions if we could monitor the ways in which metabolic roles are partitioned amongst members as microbial communities assemble, determine how resources such as carbon, nitrogen, and energy are allocated into metabolic pathways, and understand the mechanisms by which organisms and communities respond to changes in their surroundings. Because many organisms cannot be cultivated, and given that the metabolisms of those growing in monoculture are likely to differ from those of organisms growing as part of consortia, it is vital to develop methods to study microbial communities in situ. Chemoautotrophic biofilms growing in mine tunnels hundreds of meters underground drive pyrite (FeS(2)) dissolution and acid and metal release, creating habitats that select for a small number of organism types. The geochemical and microbial simplicity of these systems, the significant biomass, and clearly defined biological-inorganic feedbacks make these ecosystem microcosms ideal for development of methods for the study of uncultivated microbial consortia. Our approach begins with the acquisition of genomic data from biofilms that are sampled over time and in different growth conditions. We have demonstrated that it is possible to assemble shotgun sequence data to reveal the gene complement of the dominant community members and to use these data to confidently identify a significant fraction of proteins from the dominant organisms by mass spectrometry (MS)-based proteomics. However, there are technical obstacles currently restricting this type of "proteogenomic" analysis. Composite genomic sequences assembled from environmental data from natural microbial communities do not capture the full range of

  13. Embedded-explicit emergent literacy intervention I: Background and description of approach.

    PubMed

    Justice, Laura M; Kaderavek, Joan N

    2004-07-01

    This article, the first of a two-part series, provides background information and a general description of an emergent literacy intervention model for at-risk preschoolers and kindergartners. The embedded-explicit intervention model emphasizes the dual importance of providing young children with socially embedded opportunities for meaningful, naturalistic literacy experiences throughout the day, in addition to regular structured therapeutic interactions that explicitly target critical emergent literacy goals. The role of the speech-language pathologist (SLP) in the embedded-explicit model encompasses both indirect and direct service delivery: The SLP consults and collaborates with teachers and parents to ensure the highest quality and quantity of socially embedded literacy-focused experiences and serves as a direct provider of explicit interventions using structured curricula and/or lesson plans. The goal of this integrated model is to provide comprehensive emergent literacy interventions across a spectrum of early literacy skills to ensure the successful transition of at-risk children from prereaders to readers.

  14. Natural Sciences and Pre-Schoolers: Impact and Future Approaches

    NASA Astrophysics Data System (ADS)

    Mira, Sara; Leote, Catarina; Ferreira, Hélder; Correia, Diana; Alho, Joana; Costa, Júlio; Silva, Adriana; Faria, Cláudia; Azevedo Rodrigues, Luis

    2017-04-01

    Geosciences are more and more part of the primary school curriculum. However, the subjects of Earth and Astronomy remain very lightly approached. In Portugal, after the mandatory class period from 9 a.m. to 4 p.m., a complementary Experimental Sciences class of 1 or 2 hours per week has been introduced. In the past two years, through a partnership with the Lagos City Hall, the Lagos Ciência Viva Science Centre (CCVL) has been responsible for these classes in 8 primary schools engaging roughly 500 students in STEM activities that aim to support students to better understand and explore general scientific (and geosciences) subjects. But what is the impact of these classes in their knowledge and thinking procedure? What competencies and skills are gained, if any? And what is the background of our students regarding scientific literacy and habits? To answer these questions, we used questionnaires and personal meaning mapping to characterize our primary school population concerning scientific literacy and habits, assess the impact in their knowledge and identify potential caveats in our teaching and evaluation methods.

  15. Research on tracking approach to weak small targets under sky background

    NASA Astrophysics Data System (ADS)

    Chen, Jinling; Miao, Dong; Zhou, Wensheng; Shen, Jiarui; Chen, Nao; Kang, Bo

    2014-09-01

    The infrared (IR) target recognizing and tracking technique is widely applied to many fields such as industries, navigation, weapon controlling and guiding and so on. Its application in military field has become the research hotspot. The stability of target tracking is the most important in military applications. However, it is difficult to track the aerial target because of the complex background and noise interference, especially from long distance, which make tracking targets even harder. In this paper, a novel image tracking system is designed, which uses template matching algorithm combined with Kalman filter. Because of the noise in image, the presence of occlusion, and the deformation of tracked target, some tracking algorithms may fail. So it is the main idea in this paper to merge the advantages from the tracking algorithms, and track the target real time. The algorithm for weak small targets from the image is based on template matching algorithm. In order to overcome the problems related to the changes of unpredictable circumstance, Kalman filter tracking algorithm is used. For the disadvantage of template matching algorithm towards occasions in target tracking, such as target occlusion, drastic change of image intensity, the relevant solutions are proposed. In cases when the target is occluded or moves more than the operational limits of the tracking module, Kalman filter is used to predict the object location. Thus, automatic detection and tracking of target in real-time is achieved and the proposed method is more robust in target tracking. The results show that the algorithm can realize target tracking under complicated scenes. It also improves the tracking stability, capacity of anti-interfering and running efficiency.

  16. Effect of the genetic background on recombination frequency in the cn-vg region of the second chromosome of natural populations of Drosophila melanogaster.

    PubMed

    Hofmanová, J

    1975-01-01

    Newly established test stocks made it possible to follow the effect of three different defined genetic backgrounds (first and third chromosomes) on recombination frequency in the cn-vg region of the second chromosomes isolated from four natural populations of Drosophila melanogaster. One background was composed of the chromosomes with inversions obtained from the stock (see article) and another two backgrounds were of the standard type consisting one-half of the original chromosomes from the natural population and one-half of the chromosomes of the stocks Oregon R or Samarkand. Using the analysis of variance significant differences in RF values were found between and within populations and especially between the different backgrounds. Some simple and double interactions between the above factors played a role. The highest RF values were obtained on the background [corrected] with inversions. The effect of the different genetic backgrounds [corrected] by the action of the genetic modifiers of RF. The different genetic backgrounds affected the variations in RF values in individual populations and the different populations reacted differentially to the changed genetic background. The design of the experiment permitted an estimation of the causal compoenents of variance and heritability of RF from the sib analysis. The additive component of variance was present in only two of the populations under test; the respective estimates of heritability were very low.

  17. [Operative neurosurgery: personal view and historical backgrounds (3). Anterior circulation--pterional approach].

    PubMed

    Yonekawa, Yasuhiro

    2007-07-01

    Under the title of anterior circulation aneurysms and the pterional approach, followings are presented and emphasized along with mentioning their historical development in our present performance status. Pterional approach: head positioning with Mayfield-Kees fixation apparatus using one pin around the processus matoideus and the other 2 pins on the contralateral side behind the hair line the head turned 30 degrees and reclined chin-up l5-20 grade. Skin incision beginning just in front of the tragus ending up at the midline hair line in a curvilinear fashion always including the superficial temporal artery STA in its frontal branch and the facial nerve (frontal branch) in the skin flap. A muscle fascial preparation is so fashioned such that a strip of myofascial cuff is left at the linea temporalis and the temporal musculature is reflected and retracted towards the postero-basal direction in order to expose the pterion, for which a small short myofascial incision is added parallel to the skin incision towards the tragus up to several cm above it to prevent postoperative trismus. Bone flap is sawed out usually using three burr holes, at the key hole just at the proximal part of the linea temporalis, frontomedially on the squama frontalis and on the sutura squamosa, so that the Sylvian fissure and the superior temporal gyrus are exposed enough for further procedure. The sphenoid ridge is drilled away until the most lateral corner of the superior orbital fissure comes into view. Thus one has drilled away enough to do surgery in question at the skull base even at the time of "angry brain" due to subarachnoid hemorrhage SAH. This procedure can be followed by selective extradural anterior clinoidectomy SEAC in case of necessity. The dura is opened in a curvilinear fashion so that the dura can be reflected over the drilled sphenoid wing and so that the Sylvian fissure and the superior temporal gyrus is exposed for the treatment of aneurysms of the internal carotid artery

  18. Bayesian background estimation

    NASA Astrophysics Data System (ADS)

    Fischer, R.; Dose, V.; Hanson, K. M.; von der Linden, W.

    2001-05-01

    The ubiquitous problem of estimating the background of a measured spectrum is solved with Bayesian probability theory. A mixture model is used to capture the defining characteristics of the problem, namely that the background is smoother than the signal. The smoothness property is quantified in terms of a cubic spline basis where a variable degree of smoothness is attained by allowing the number of knots and the knot positions to be adaptively chosen on the basis of the data. The fully Bayesian approach taken provides a natural way to handle knot adaptivity, allows uncertainties in the background to be estimated and data points to be classified in groups containing only background and groups with additional signal contribution. Our technique is demonstrated on a PIXE spectrum from a geological sample and an Auger spectrum from an 10 monolayer iron film on tungsten.

  19. Educating for and through Nature: A Merleau-Pontian Approach

    ERIC Educational Resources Information Center

    Hung, Ruyu

    2008-01-01

    This paper aims to explore the relationship between humans and nature and the implied intimacy, so-call "ecophilia," in light of the French philosopher Maurice Merleau-Ponty. It is revealed from the Merleau-Pontian view of body and nature that there may be a more harmonious relationship between humankind and nature than the commonly assumed, and…

  20. Educating for and through Nature: A Merleau-Pontian Approach

    ERIC Educational Resources Information Center

    Hung, Ruyu

    2008-01-01

    This paper aims to explore the relationship between humans and nature and the implied intimacy, so-call "ecophilia," in light of the French philosopher Maurice Merleau-Ponty. It is revealed from the Merleau-Pontian view of body and nature that there may be a more harmonious relationship between humankind and nature than the commonly assumed, and…

  1. Oil and Gas Drilling and Operations in Cave and Karst area: Background and development of a BLM approach

    SciTech Connect

    Goodbar, J.R. )

    1994-03-01

    Karst lands pose a unique set of problems for the oil and gas industry, as well as for the cave and karst environments. Since 1987, the Bureau of Land Management (BLM) has been working with the oil and gas industry to develop acceptable practices for drilling and operation in karst lands. The mutual goals of industry and of the BLM is to minimize the potential of encountering those problems and reduce the extent of the problems, if they are encountered. BLM's approach is described in their [open quotes]Draft Guide for Oil and Gas Drilling and Operations in Cave and Karst Areas.[close quotes] This paper discusses the background and development of this guide with an emphasis on the conflict resolution approach of the BLM.

  2. Marine Natural Product Chemistry and the Interim: A Novel Approach

    ERIC Educational Resources Information Center

    Bland, Jeffrey S.; Medcalf, Darrell G.

    1974-01-01

    Describes a course designed to strengthen a student's background in organic chemistry, demonstrate the interfacing of chemistry and biology, expose undergraduates to graduate research, provide familiarity with instrumentation, and provide a novel field experience. (Author/GS)

  3. Global Natural Disaster Risk Hotspots: Transition to a Regional Approach

    NASA Astrophysics Data System (ADS)

    Lerner-Lam, A.; Chen, R.; Dilley, M.

    2005-12-01

    The "Hotspots Project" is a collaborative study of the global distribution and occurrence of multiple natural hazards and the associated exposures of populations and their economic output. In this study we assess the global risks of two disaster-related outcomes: mortality and economic losses. We estimate risk levels by combining hazard exposure with historical vulnerability for two indicators of elements at risk-gridded population and Gross Domestic Product (GDP) per unit area - for six major natural hazards: earthquakes, volcanoes, landslides, floods, drought, and cyclones. By calculating relative risks for each grid cell rather than for countries as a whole, we are able to estimate risk levels at sub-national scales. These can then be used to estimate aggregate relative multiple hazard risk at regional and national scales. Mortality-related risks are assessed on a 2.5' x 2.5' latitude-longitude grid of global population (GPW Version 3). Economic risks are assessed at the same resolution for gridded GDP per unit area, using World Bank estimates of GDP based on purchasing power parity. Global hazard data were compiled from multiple sources. The project collaborated directly with UNDP and UNEP, the International Research Institute for Climate Prediction (IRI) at Columbia, and the Norwegian Geotechnical Institute (NGI) in the creation of data sets for several hazards for which global data sets did not previously exist. Drought, flood and volcano hazards are characterized in terms of event frequency, storms by frequency and severity, earthquakes by frequency and ground acceleration exceedance probability, and landslides by an index derived from probability of occurrence. The global analysis undertaken in this project is clearly limited by issues of scale as well as by the availability and quality of data. For some hazards, there exist only 15- to 25-year global records with relatively crude spatial information. Data on historical disaster losses, and particularly on

  4. Exceedance probability map: a tool helping the definition of arsenic Natural Background Level (NBL) within the Drainage Basin to the Venice Lagoon (NE Italy)

    NASA Astrophysics Data System (ADS)

    Dalla Libera, Nico; Fabbri, Paolo; Mason, Leonardo; Piccinini, Leonardo; Pola, Marco

    2017-04-01

    Arsenic groundwater contamination affects worldwide shallower groundwater bodies. Starting from the actual knowledges around arsenic origin into groundwater, we know that the major part of dissolved arsenic is naturally occurring through the dissolution of As-bearing minerals and ores. Several studies on the shallow aquifers of both the regional Venetian Plain (NE Italy) and the local Drainage Basin to the Venice Lagoon (DBVL) show local high arsenic concentration related to peculiar geochemical conditions, which drive arsenic mobilization. The uncertainty of arsenic spatial distribution makes difficult both the evaluation of the processes involved in arsenic mobilization and the stakeholders' decision about environmental management. Considering the latter aspect, the present study treats the problem of the Natural Background Level (NBL) definition as the threshold discriminating the natural contamination from the anthropogenic pollution. Actually, the UE's Directive 2006/118/EC suggests the procedures and criteria to set up the water quality standards guaranteeing a healthy status and reversing any contamination trends. In addition, the UE's BRIDGE project proposes some criteria, based on the 90th percentile of the contaminant's concentrations dataset, to estimate the NBL. Nevertheless, these methods provides just a statistical NBL for the whole area without considering the spatial variation of the contaminant's concentration. In this sense, we would reinforce the NBL concept using a geostatistical approach, which is able to give some detailed information about the distribution of arsenic concentrations and unveiling zones with high concentrations referred to the Italian drinking water standard (IDWS = 10 µg/liter). Once obtained the spatial information about arsenic distribution, we can apply the 90th percentile methods to estimate some Local NBL referring to every zones with arsenic higher than IDWS. The indicator kriging method was considered because it

  5. A Geographic Approach to the Study of Natural Gas.

    ERIC Educational Resources Information Center

    Sheskin, Ira M.

    1980-01-01

    Provides information, tips, references, and materials to high school and college level geography teachers on developing a unit on natural gas. Data are presented in the form of tables, maps, figures, and textual analysis. (Author/DB)

  6. A Geographic Approach to the Study of Natural Gas.

    ERIC Educational Resources Information Center

    Sheskin, Ira M.

    1980-01-01

    Provides information, tips, references, and materials to high school and college level geography teachers on developing a unit on natural gas. Data are presented in the form of tables, maps, figures, and textual analysis. (Author/DB)

  7. Exploiting new approaches for natural product drug discovery in the biotechnology industry.

    PubMed

    Gullo, Vincent P; Hughes, Dallas E

    2005-01-01

    In recent years, large pharmaceutical companies have significantly reduced or eliminated the search for new therapeutic agents from natural sources. In spite of the many successes from natural product drug discovery, these companies have chosen to focus on compound libraries as the source of new lead compounds. Smaller biotechnology companies are continuing the search for novel natural products by developing and employing new and innovative approaches. This paper will describe some of these recent approaches to natural product drug discovery.:

  8. Abandoning Patchwork Approaches to Nature of Science in Science Education

    ERIC Educational Resources Information Center

    Dagher, Zoubeida R.; Erduran, Sibel

    2017-01-01

    The purpose of this commentary on Hodson and Wong's (2017, this issue) article is to clarify the merits of the expanded family resemblance approach (FRA) to science education, briefly alluded to in their article, and to discuss the implications of this approach relative to the question of demarcation they raise. In clarifying the merits of the…

  9. An hermeneutic approach to studying the nature of wilderness experiences

    Treesearch

    Michael E. Patterson; Alan E. Watson; Daniel R. Williams; Joseph R. Roggenbuck

    1998-01-01

    The most prevalent approach to understanding recreation experiences in resource management has been a motivational research program that views satisfaction as an appropriate indicator of experience quality. This research explores a different approach to studying the quality of recreation experiences. Rather than viewing recreation experiences as a linear sequence of...

  10. Natural background and anthropogenic inputs of polycyclic aromatic hydrocarbons (PAH) in sediments of South-Western Barents Sea.

    PubMed

    Boitsov, Stepan; Jensen, H K B; Klungsøyr, Jarle

    2009-12-01

    Polycyclic aromatic hydrocarbons (PAH) were measured in sediment cores from 13 locations in South-Western Barents Sea as part of a detailed study of the Norwegian seabed under the MAREANO program. The generally low PAH levels found, an average around 200 ng g(-1) dry weight for sum PAH, indicate low inputs of petroleum hydrocarbons to the marine environment in the area. Differences in PAH composition and various PAH ratios indicate a natural, mostly petrogenic origin of PAH in sediments from the open sea locations, while the fjord locations show higher pyrogenic PAH contents with an increase towards upper sediment layers, indicating low inputs from human activities. Petrogenic PAH levels increase in deeper sediments at open sea locations, also when normalised to total organic carbon (TOC) contents, suggesting natural leakages of oil-related hydrocarbons in the area.

  11. Novel approaches for stability improvement in natural medicines.

    PubMed

    Thakur, Lovely; Ghodasra, Umang; Patel, Nilesh; Dabhi, Mahesh

    2011-01-01

    Natural product market has seen tremendous growth in the last few years. It results in the formulation of a number of proprietary herbal products, majority of them being multi-component formulations. With the advancement of herbal drug treatments, it has now been observed that many of the constituents present in the drug may react with each other, raising the serious concern about the stability of such formulations which is an important issue in the field of phytochemistry and natural medicines. Natural products are often prone to deterioration, especially during storage, leading to loss of active component, production of metabolites with no activity and, in extreme cases, production of toxic metabolites. This area needs to be addressed in order to determine the efficacy of the formulation. Understanding the problems related to natural product stability can give the idea of dealing with the stability issues. Modifications of the conventional herbal formulations can deal with the stability problems to a large extent. This article deals with the stability problems and is aimed to provide some tools and techniques to increase stability of natural medicines and herbal formulations.

  12. Novel approaches for stability improvement in natural medicines

    PubMed Central

    Thakur, Lovely; Ghodasra, Umang; Patel, Nilesh; Dabhi, Mahesh

    2011-01-01

    Natural product market has seen tremendous growth in the last few years. It results in the formulation of a number of proprietary herbal products, majority of them being multi-component formulations. With the advancement of herbal drug treatments, it has now been observed that many of the constituents present in the drug may react with each other, raising the serious concern about the stability of such formulations which is an important issue in the field of phytochemistry and natural medicines. Natural products are often prone to deterioration, especially during storage, leading to loss of active component, production of metabolites with no activity and, in extreme cases, production of toxic metabolites. This area needs to be addressed in order to determine the efficacy of the formulation. Understanding the problems related to natural product stability can give the idea of dealing with the stability issues. Modifications of the conventional herbal formulations can deal with the stability problems to a large extent. This article deals with the stability problems and is aimed to provide some tools and techniques to increase stability of natural medicines and herbal formulations. PMID:22096318

  13. Management of Combined Natural Risks - A New Approach: Keynote Address

    NASA Astrophysics Data System (ADS)

    Hanisch, Jörg

    A new attempt is made to illustrate and to quantify the relationships of individual natural hazards, their combinations and the human vulnerability to natural hazards. During many catastrophic events, combinations of different natural events aggravate their occurrence substantially. Earthquakes are frequently associated with heavy landsliding (El Salvador 2001) and heavy rainstorms are able to trigger fast running debris flows and not only floods (like during the Mitch disaster in Central America in 1998). That signifies that natural hazard maps should show the combinations of different hazards and their genetic relationships. To put into effect this, first, the individual hazards have to be assessed and presented in hazard zones (0 to 3). Then these hazards zones will be overlain using GIS techniques. In this way, e.g., an earthquake-prone area which coincides with an area susceptible to landslides (ranking 0 to 3 as well) can show hazard concentrations of up to a value of 6, simply adding the individual hazard zones. To get the result of the corresponding risk zones, the vulnerability maps of human settlements and infra-structure have to be overlain on the maps of these combinations of natural hazards.

  14. Determination of environmental radioactivity (238U, 232Th and 40K) and indoor natural background radiation level in Chennai city (Tamilnadu State), India.

    PubMed

    Babai, K S; Poongothai, S; Punniyakotti, J

    2013-01-01

    An extensive study on the determination of the natural radioactivity ((238)U, (232)Th and (40)K) levels in soil samples of Chennai city, India has been undertaken and the results of the same are compared with the levels reported in other Indian cities as well as other parts of the world. The radioactivity content in the soil samples, the absorbed dose rate, annual effective dose equivalent, radium equivalent activity, internal and external hazard indices were calculated and compared with UNSCEAR 2000 recommended values. In addition to the above, mapping of indoor natural background gamma radiation levels has been made using thermo luminescent dosemeters throughout Chennai city and the same are reported.

  15. Naturism and sexuality: broadening our approach to sexual wellbeing.

    PubMed

    Smith, Glenn; King, Michael

    2009-06-01

    This study aimed to investigate how people manage their sexuality when practicing naturism in the United Kingdom (UK). Thirty-nine self-identified naturists from across the UK were interviewed. Sexuality, when practicing naturism, was found often to be suppressed through the use of rules, geographical isolation and thoughts and behaviour. Some participants found ways of exploring and enjoying their sexuality by keeping feelings hidden and/or seeking out more sympathetic naturist environments. Naturist environments may offer a unique space in which to explore aspects of our sexuality that are currently pathologised, criminalised or commercialised. This has important implications for sexual health policy and promotion.

  16. Approaching Nature and Science through Outdoor Experience and Drama.

    ERIC Educational Resources Information Center

    Karvonen-Lee, Vireo

    1997-01-01

    Unit of study about rocks and the layers of the Earth focuses on building children's respect for nature by developing feelings of intimate relationship. Lesson plans include science activities (rock gathering, Earth models); "drama from the outside" (ritual to promote respect); literature readings; and "dramas from the inside"…

  17. Approaching Nature and Science through Outdoor Experience and Drama.

    ERIC Educational Resources Information Center

    Karvonen-Lee, Vireo

    1997-01-01

    Unit of study about rocks and the layers of the Earth focuses on building children's respect for nature by developing feelings of intimate relationship. Lesson plans include science activities (rock gathering, Earth models); "drama from the outside" (ritual to promote respect); literature readings; and "dramas from the inside"…

  18. Rill erosion in natural and disturbed forests: 2. Modeling approaches

    Treesearch

    J. W. Wagenbrenner; P. R. Robichaud; W. J. Elliot

    2010-01-01

    As forest management scenarios become more complex, the ability to more accurately predict erosion from those scenarios becomes more important. In this second part of a two-part study we report model parameters based on 66 simulated runoff experiments in two disturbed forests in the northwestern U.S. The 5 disturbance classes were natural, 10-month old and 2-week old...

  19. The approaches for the decision support in case natural hazards

    NASA Astrophysics Data System (ADS)

    Vyazilov, Evgeny; Chunyaev, Nikita

    2013-04-01

    In spite of using highly automated systems of measurement, collecting, storing, handling, prediction and delivery of information on the marine environment, including natural hazards, the amount of damage from natural phenomena increases. Because information on the marine environment delivered to the industrial facilities not effectively used. To such information pays little attention by individual decision-makers and not always perform preventive measures necessary for reduce and prevent damage. Automation of information support will improve the efficiency management of the marine activities. In Russia develops "The Unified system of the information about World ocean" (ESIMO, http://esimo.ru/), that integrates observation, analysis, prognostic and climate data. Necessary to create tools to automatic selection natural disasters through all integrated data; notification decision-makers about arising natural hazards - software agent; provision of information in a compact form for the decision-makers; assessment of possible damage and costs to the preventive measures; providing information on the impacts of environment on economic facilities and recommendations for decision-making; the use of maps, diagrams, tables for reporting. Tools for automatic selection designed for identification of natural phenomena based on the resources ESIMO and corresponding critical values of the indicators environment. The result of this module will be constantly updated database of critical situations of environment for each object or technological process. To operational notify and provide current information about natural hazards proposes using a software agent that is installed on the computer decision-makers, which is activated in case critical situations and provides a minimum of information. In the event of natural disaster software agent should be able to inform decision-makers about this, providing information on the current situation, and the possibility for more and detailed

  20. Role of light and heavy minerals on natural radioactivity level of high background radiation area, Kerala, India.

    PubMed

    Ramasamy, V; Sundarrajan, M; Suresh, G; Paramasivam, K; Meenakshisundaram, V

    2014-02-01

    Natural radionuclides ((238)U, (232)Th and (40)K) concentrations and eight different radiological parameters have been analyzed for the beach sediments of Kerala with an aim of evaluating the radiation hazards. Activity concentrations ((238)U and (232)Th) and all the radiological parameters in most of the sites have higher values than recommended values. The Kerala beach sediments pose significant radiological threat to the people living in the area and tourists going to the beaches for recreation or to the sailors and fishermen involved in their activities in the study area. In order to know the light mineral characterization of the present sediments, mineralogical analysis has been carried out using Fourier transform infrared (FTIR) spectroscopic technique. The eight different minerals are identified and they are characterized. Among the various observed minerals, the minerals such as quartz, microcline feldspar, kaolinite and calcite are major minerals. The relative distribution of major minerals is determined by calculating extinction co-efficient and the values show that the amount of quartz is higher than calcite and much higher than microcline feldspar. Crystallinity index is calculated to know the crystalline nature of quartz present in the sediments. Heavy mineral separation analysis has been carried out to know the total heavy mineral (THM) percentage. This analysis revealed the presence of nine heavy minerals. The minerals such as monazite, zircon, magnetite and illmenite are predominant. Due to the rapid and extreme changes occur in highly dynamic environments of sandy beaches, quantities of major light and heavy minerals are widely varied from site to site. Granulometric analysis shows that the sand is major content. Multivariate statistical (Pearson correlation, cluster and factor) analysis has been carried out to know the effect of mineralogy on radionuclide concentrations. The present study concluded that heavy minerals induce the (238)U and (232)Th

  1. Systems Biology Approaches to Understand Natural Products Biosynthesis.

    PubMed

    Licona-Cassani, Cuauhtemoc; Cruz-Morales, Pablo; Manteca, Angel; Barona-Gomez, Francisco; Nielsen, Lars K; Marcellin, Esteban

    2015-01-01

    Actinomycetes populate soils and aquatic sediments that impose biotic and abiotic challenges for their survival. As a result, actinomycetes metabolism and genomes have evolved to produce an overwhelming diversity of specialized molecules. Polyketides, non-ribosomal peptides, post-translationally modified peptides, lactams, and terpenes are well-known bioactive natural products with enormous industrial potential. Accessing such biological diversity has proven difficult due to the complex regulation of cellular metabolism in actinomycetes and to the sparse knowledge of their physiology. The past decade, however, has seen the development of omics technologies that have significantly contributed to our better understanding of their biology. Key observations have contributed toward a shift in the exploitation of actinomycete's biology, such as using their full genomic potential, activating entire pathways through key metabolic elicitors and pathway engineering to improve biosynthesis. Here, we review recent efforts devoted to achieving enhanced discovery, activation, and manipulation of natural product biosynthetic pathways in model actinomycetes using genome-scale biological datasets.

  2. Radon exhalation rate and natural radionuclide content in building materials of high background areas of Ramsar, Iran.

    PubMed

    Bavarnegin, E; Fathabadi, N; Vahabi Moghaddam, M; Vasheghani Farahani, M; Moradi, M; Babakhni, A

    2013-03-01

    Radon exhalation rates from building materials used in high background radiation areas (HBRA) of Ramsar were measured using an active radon gas analyzer with an emanation container. Radon exhalation rates from these samples varied from below the lower detection limit up to 384 Bq.m(-2) h(-1). The (226)Ra, (232)Th and (40)K contents were also measured using a high resolution HPGe gamma- ray spectrometer system. The activity concentration of (226)Ra, (232)Th and (40)K content varied from below the minimum detection limit up to 86,400 Bq kg(-1), 187 Bq kg(-1) and 1350 Bq kg(-1), respectively. The linear correlation coefficient between radon exhalation rate and radium concentration was 0.90. The result of this survey shows that radon exhalation rate and radium content in some local stones used as basements are extremely high and these samples are main sources of indoor radon emanation as well as external gamma radiation from uranium series. Copyright © 2012 Elsevier Ltd. All rights reserved.

  3. Natural Environment Exploration Approach: The Case Study in Department of Biology, Universitas Negeri Semarang

    ERIC Educational Resources Information Center

    Alimah, Siti; Susilo, Herawati; Amin, Moh

    2016-01-01

    The study reports the evaluation and analysis of the implementation of the Nature Environment Exploration approach in the Department of Biology, Universitas Negeri Semarang State University. The method used was survey method. The results showed that the implementation of the Nature Environment Exploration approach was still far from optimal…

  4. Sparsely Ionizing Diagnostic and Natural Background Radiations are Likely Preventing Cancer and Other Genomic-Instability-Associated Diseases

    PubMed Central

    Scott, Bobby R.; Di Palma, Jennifer

    2007-01-01

    Routine diagnostic X-rays (e.g., chest X-rays, mammograms, computed tomography scans) and routine diagnostic nuclear medicine procedures using sparsely ionizing radiation forms (e.g., beta and gamma radiations) stimulate the removal of precancerous neo-plastically transformed and other genomically unstable cells from the body (medical radiation hormesis). The indicated radiation hormesis arises because radiation doses above an individual-specific stochastic threshold activate a system of cooperative protective processes that include high-fidelity DNA repair/apoptosis (presumed p53 related), an auxiliary apoptosis process (PAM process) that is presumed p53-independent, and stimulated immunity. These forms of induced protection are called adapted protection because they are associated with the radiation adaptive response. Diagnostic X-ray sources, other sources of sparsely ionizing radiation used in nuclear medicine diagnostic procedures, as well as radioisotope-labeled immunoglobulins could be used in conjunction with apopto-sis-sensitizing agents (e.g., the natural phenolic compound resveratrol) in curing existing cancer via low-dose fractionated or low-dose, low-dose-rate therapy (therapeutic radiation hormesis). Evidence is provided to support the existence of both therapeutic (curing existing cancer) and medical (cancer prevention) radiation hormesis. Evidence is also provided demonstrating that exposure to environmental sparsely ionizing radiations, such as gamma rays, protect from cancer occurrence and the occurrence of other diseases via inducing adapted protection (environmental radiation hormesis). PMID:18648608

  5. New approach to flavor symmetry and an extended naturalness principle

    NASA Astrophysics Data System (ADS)

    Barr, S. M.

    2010-09-01

    A class of nonsupersymmetric extensions of the standard model is proposed in which there is a multiplicity of light scalar doublets in a multiplet of a nonabelian family group with the standard model Higgs doublet. Anthropic tuning makes the latter light, and consequently the other scalar doublets remain light because of the family symmetry. The family symmetry greatly constrains the pattern of flavor-changing neutral-current interactions (FCNC) and p decay operators coming from scalar-exchange. Such models show that useful constraints on model-building can come from an extended naturalness principle when the electroweak scale is anthropically tuned.

  6. Proteogenemic Approaches for the Molecular Characterization of Natural Microbial Communities

    SciTech Connect

    Banfield, Jillian F.

    2014-04-25

    Microbial biofilms involved in acid mine drainage formation have served as a model systems for the study of microbial communities. Over the grant period we developed community metagenomic methods for recovery of genomes of uncultivated bacteria, archaea, viruses/phage, and plasmids from natural systems. We leveraged highly curated metagenomic datasets to develop methods to monitor microbial function in situ. Beyond new insight into extremophilic microbial ecosystems, we have shown that our strain-resolved proteogenomic methods can be applied to other systems. Our studies have uncovered new patters of inter-species recombination that likely lead to fine-scale environmental adaptation, defined the importance of inter-species vs. intra-species recombination in archaea, and evaluated the processes shaping fine-scale sequence variation. The project was the subject of study for six Ph.D. students, two of whom are now Associate Professors, the others are post docs; for M.S. or undergraduate researchers, and thirteen post docs, ten of which are now Assistant or Associate professors. The research generated 53 publications, five of which appeard in Science or Nature.

  7. Systems Biology Approaches to Understand Natural Products Biosynthesis

    PubMed Central

    Licona-Cassani, Cuauhtemoc; Cruz-Morales, Pablo; Manteca, Angel; Barona-Gomez, Francisco; Nielsen, Lars K.; Marcellin, Esteban

    2015-01-01

    Actinomycetes populate soils and aquatic sediments that impose biotic and abiotic challenges for their survival. As a result, actinomycetes metabolism and genomes have evolved to produce an overwhelming diversity of specialized molecules. Polyketides, non-ribosomal peptides, post-translationally modified peptides, lactams, and terpenes are well-known bioactive natural products with enormous industrial potential. Accessing such biological diversity has proven difficult due to the complex regulation of cellular metabolism in actinomycetes and to the sparse knowledge of their physiology. The past decade, however, has seen the development of omics technologies that have significantly contributed to our better understanding of their biology. Key observations have contributed toward a shift in the exploitation of actinomycete’s biology, such as using their full genomic potential, activating entire pathways through key metabolic elicitors and pathway engineering to improve biosynthesis. Here, we review recent efforts devoted to achieving enhanced discovery, activation, and manipulation of natural product biosynthetic pathways in model actinomycetes using genome-scale biological datasets. PMID:26697425

  8. Hepatitis C Virus and Natural Compounds: a New Antiviral Approach?

    PubMed Central

    Calland, Noémie; Dubuisson, Jean; Rouillé, Yves; Séron, Karin

    2012-01-01

    Hepatitis C is a major global health burden with an estimated 160 million infected individuals worldwide. This long-term disease evolves slowly, often leading to chronicity and potentially to liver failure. There is no anti-HCV vaccine, and, until recently, the only treatment available, based on pegylated interferon and ribavirin, was partially effective, and had considerable side effects. With recent advances in the understanding of the HCV life cycle, the development of promising direct acting antivirals (DAAs) has been achieved. Their use in combination with the current treatment has led to encouraging results for HCV genotype 1 patients. However, this therapy is quite expensive and will probably not be accessible for all patients worldwide. For this reason, constant efforts are being made to identify new antiviral molecules. Recent reports about natural compounds highlight their antiviral activity against HCV. Here, we aim to review the natural molecules that interfere with the HCV life cycle and discuss their potential use in HCV therapy. PMID:23202460

  9. A systems approach to model natural variation in reactive properties of bacterial ribosomes

    PubMed Central

    Jackson, Julius H; Schmidt, Thomas M; Herring, Patricia A

    2008-01-01

    Background Natural variation in protein output from translation in bacteria and archaea may be an organism-specific property of the ribosome. This paper adopts a systems approach to model the protein output as a measure of specific ribosome reactive properties in a ribosome-mediated translation apparatus. We use the steady-state assumption to define a transition state complex for the ribosome, coupled with mRNA, tRNA, amino acids and reaction factors, as a subsystem that allows a focus on the completed translational output as a measure of specific properties of the ribosome. Results In analogy to the steady-state reaction of an enzyme complex, we propose a steady-state translation complex for mRNA from any gene, and derive a maximum specific translation activity, Ta(max), as a property of the ribosomal reaction complex. Ta(max) has units of a-protein output per time per a-specific mRNA. A related property of the ribosome, T˜a(max⁡), has units of a-protein per time per total RNA with the relationship T˜a(max⁡) = ρa Ta(max), where ρa represents the fraction of total RNA committed to translation output of Pa from gene a message. Ta(max) as a ribosome property is analogous to kcat for a purified enzyme, and T˜a(max⁡) is analogous to enzyme specific activity in a crude extract. Conclusion Analogy to an enzyme reaction complex led us to a ribosome reaction model for measuring specific translation activity of a bacterial ribosome. We propose to use this model to design experimental tests of our hypothesis that specific translation activity is a ribosomal property that is subject to natural variation and natural selection much like Vmax and Km for any specific enzyme. PMID:18620602

  10. Systematic approaches to comprehensive analyses of natural organic matter

    USGS Publications Warehouse

    Leenheer, Jerry A.

    2009-01-01

    The more that is learned of the chemistry of aquatic natural organic matter (NOM) the greater is the scientific appreciation of the vast complexity of this subject. This complexity is due not only to a multiplicity of precursor molecules in any environment but to their associations with each other and with other components of local environments such as clays, mineral acids and dissolved metals. In addition, this complex system is subject to constant change owing to environmental variables and microbial action. Thus, there is a good argument that no two NOM samples are exactly the same even from the same source at nearly the same time. When ubiquity of occurrence, reaction with water treatment chemicals, and subsequent human exposure are added to the list of NOM issues, one can understand the appeal that this subject holds for a wide variety of environmental scientists.

  11. Evaluation of natural language processing systems: Issues and approaches

    SciTech Connect

    Guida, G.; Mauri, G.

    1986-07-01

    This paper encompasses two main topics: a broad and general analysis of the issue of performance evaluation of NLP systems and a report on a specific approach developed by the authors and experimented on a sample test case. More precisely, it first presents a brief survey of the major works in the area of NLP systems evaluation. Then, after introducing the notion of the life cycle of an NLP system, it focuses on the concept of performance evaluation and analyzes the scope and the major problems of the investigation. The tools generally used within computer science to assess the quality of a software system are briefly reviewed, and their applicability to the task of evaluation of NLP systems is discussed. Particular attention is devoted to the concepts of efficiency, correctness, reliability, and adequacy, and how all of them basically fail in capturing the peculiar features of performance evaluation of an NLP system is discussed. Two main approaches to performance evaluation are later introduced; namely, black-box- and model-based, and their most important characteristics are presented. Finally, a specific model for performance evaluation proposed by the authors is illustrated, and the results of an experiment with a sample application are reported. The paper concludes with a discussion on research perspective, open problems, and importance of performance evaluation to industrial applications.

  12. COMPARISON OF NATURAL BACKGROUND DOSE RATES FOR RESIDENTS OF THE AMARGOSA VALLEY, NV, TO THOSE IN LEADVILLE, CO, AND THE STATES OF COLORADO AND NEVADA

    SciTech Connect

    D. Moeller and L. C. Sun

    2006-02-24

    In the latter half of 2005, the U.S. Environmental Protection Agency (USEPA) published a Proposed Rule (40 CFR Part 197) for establishing a dose rate standard for limiting radionuclide releases from the proposed Yucca Mountain high-level radioactive waste repository during the time period from 10{sup 4} to 10{sup 6} years after closure. The proposed standard was based on the difference in the estimated total dose rate from natural background in the Amargosa Valley and the ''average annual background radiation'' for the State of Colorado. As defined by the USEPA, ''natural background radiation consists of external exposures from cosmic and terrestrial sources, and internal exposures from indoor exposures to naturally-occurring radon''. On the basis of its assessments, the USEPA estimated that the difference in the dose rate in the two identified areas was 3.5 mSv y{sup -1}. The purpose of this review was to provide an independent evaluation and review of this estimate. One of the first observations was that, because site-specific dose rate measurements for the Amargosa Valley ''were not available'', the dose rates for various sources of natural background in that area, used by the USEPA in its assessment, were based on modifications of the average values for the State of Nevada. A second observation was that the conversion factor applied in estimating the dose rates due to exposures to indoor radon and its decay products was a factor of 2 higher than the currently accepted value. Further review revealed that site-specific data for many natural background sources in the Amargosa Valley were available. One particularly important observation was that about 91% of the residents of that area live in mobile homes which, due to their construction and design, have indoor radon concentrations comparable to, or less than, those outdoors. For that reason, alone, the USEPA estimate of the average dose rate for residents of the Amargosa Valley, due to indoor radon, was not valid

  13. A conformal variational approach for helices in nature

    NASA Astrophysics Data System (ADS)

    Barros, Manuel; Ferrández, Angel

    2009-10-01

    We propose a two step variational principle to describe helical structures in nature. The first one is governed by an energy action which is a linear function in both curvature and torsion allowing to describe nonclosed structures including elliptical, spherical, and conical helices. These appear as rhumb lines in right cylinders constructed over plane curves. The model is completed with a conformal alternative which, in particular, gives a description of closed structures. The energy action is linear in the curvatures when computed in a conformal spherical metric. Now, helices appear as making a constant angle with a Villarceau flow and so they are loxodromes in surfaces which are stereographic projections of Hopf tubes, in particular, anchor rings, revolution tori, and Dupin cyclides. The model satisfies the requirements of simplicity and beauty as reflected in the three main principles that head its construction: least action, topological, and quantization. According to the latter, the main entities and quantities associated with the model should not be multiplied unnecessarily but they are quantized. In this sense, a quantization principle, a la Dirac, is obtained for closed structures and also for the critical levels of energy.

  14. Parents' Experiences of the Provision of Community-Based Family Support and Therapy Services Utilizing the Strengths Approach and Natural Learning Environments

    ERIC Educational Resources Information Center

    Carlson, Glenys; Armitstead, Clare; Rodger, Sylvia; Liddle, Gwen

    2010-01-01

    Background: In recent years, community based therapy service providers have explored different service delivery models to optimize child and family outcomes. This qualitative study aimed to explore parents' experiences of one particular service team that adopted a strengths approach, utilizing natural learning environments. Materials and methods:…

  15. Parents' Experiences of the Provision of Community-Based Family Support and Therapy Services Utilizing the Strengths Approach and Natural Learning Environments

    ERIC Educational Resources Information Center

    Carlson, Glenys; Armitstead, Clare; Rodger, Sylvia; Liddle, Gwen

    2010-01-01

    Background: In recent years, community based therapy service providers have explored different service delivery models to optimize child and family outcomes. This qualitative study aimed to explore parents' experiences of one particular service team that adopted a strengths approach, utilizing natural learning environments. Materials and methods:…

  16. Assessment of indoor radiation dose received by the residents of natural high background radiation areas of coastal villages of Kanyakumari district, Tamil Nadu, India

    NASA Astrophysics Data System (ADS)

    Deva Jayanthi, D.; Maniyan, C. G.; Perumal, S.

    2011-07-01

    Radiation exposure and effective dose received through two routes of exposure, viz. external and internal, via inhalation, by residents of 10 villages belonging to Natural High Background Radiation Areas (NHBRA) of coastal regions of Kanyakumari District and Tamil Nadu in India were studied. While the indoor gamma radiation levels were monitored using Thermo Luminescent Dosimeters (TLDs), the indoor radon and thoron gas concentrations were measured using twin chamber dosimeters employing Solid State Nuclear Track Detectors (SSNTDs, LR-115-II). The average total annual effective dose was estimated and found to be varying from 2.59 to 8.76 mSv.

  17. The Notional-Functional Approach: Teaching the Real Language in Its Natural Context.

    ERIC Educational Resources Information Center

    Laine, Elaine

    This study of the notional-functional approach to second language teaching reviews the history and theoretical background of the method, current issues, and implementation of a notional-functional syllabus. Chapter 1 discusses the history and theory of the approach and the organization and advantages of the notional-functional syllabus. Chapter 2…

  18. Background estimation in experimental spectra

    SciTech Connect

    Fischer, R.; Hanson, K. M.; Dose, V.; Linden, W. von der

    2000-02-01

    A general probabilistic technique for estimating background contributions to measured spectra is presented. A Bayesian model is used to capture the defining characteristics of the problem, namely, that the background is smoother than the signal. The signal is allowed to have positive and/or negative components. The background is represented in terms of a cubic spline basis. A variable degree of smoothness of the background is attained by allowing the number of knots and the knot positions to be adaptively chosen on the basis of the data. The fully Bayesian approach taken provides a natural way to handle knot adaptivity and allows uncertainties in the background to be estimated. Our technique is demonstrated on a particle induced x-ray emission spectrum from a geological sample and an Auger spectrum from iron, which contains signals with both positive and negative components. (c) 2000 The American Physical Society.

  19. Monitoring Perinatal Gut Microbiota in Mouse Models by Mass Spectrometry Approaches: Parental Genetic Background and Breastfeeding Effects

    PubMed Central

    Levi Mortera, Stefano; Del Chierico, Federica; Vernocchi, Pamela; Rosado, Maria M.; Cavola, Agnese; Chierici, Marco; Pieroni, Luisa; Urbani, Andrea; Carsetti, Rita; Lante, Isabella; Dallapiccola, Bruno; Putignani, Lorenza

    2016-01-01

    At birth, contact with external stimuli, such as nutrients derived from food, is necessary to modulate the symbiotic balance between commensal and pathogenic bacteria, protect against bacterial dysbiosis, and initiate the development of the mucosal immune response. Among a variety of different feeding patterns, breastfeeding represents the best modality. In fact, the capacity of breast milk to modulate the composition of infants’ gut microbiota leads to beneficial effects on their health. In this study, we used newborn mice as a model to evaluate the effect of parental genetic background (i.e., IgA-producing mice and IgA-deficient mice) and feeding modulation (i.e., maternal feeding and cross-feeding) on the onset and shaping of gut microbiota after birth. To investigate these topics, we used either a culturomic approach that employed Matrix Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MS), or bottom–up Liquid Chromatography, with subsequent MSMS shotgun metaproteomic analysis that compared and assembled results of the two techniques. We found that the microbial community was enriched by lactic acid bacteria when pups were breastfed by wild-type (WT) mothers, while IgA-deficient milk led to an increase in the opportunistic bacterial pathogen (OBP) population. Cross-feeding results suggested that IgA supplementation promoted the exclusion of some OBPs and the temporary appearance of beneficial species in pups fed by WT foster mothers. Our results show that both techniques yield a picture of microbiota from different angles and with varying depths. In particular, our metaproteomic pipeline was found to be a reliable tool in the description of microbiota. Data from these studies are available via ProteomeXchange, with identifier PXD004033. PMID:27725814

  20. Estimating COCOM Natural Background Dormancy

    DTIC Science & Technology

    2015-04-01

    did not include in this analysis areas that are evergreen, such as the Congo Basin and Amazon Basin tropical rainforests . We weighted the dormant...dormancy decreas- es to the southwest to a minimum of about 25 days as the conditions to support tropical rainforest , with sufficient moisture in all...months to sup- port plant growth, become more dominant (Ryerson et al. 2013b). 5.2.3 SOUTHCOM The tropical rainforest in SOUTHCOM is perennially green

  1. A record-based case-control study of natural background radiation and the incidence of childhood leukaemia and other cancers in Great Britain during 1980-2006.

    PubMed

    Kendall, G M; Little, M P; Wakeford, R; Bunch, K J; Miles, J C H; Vincent, T J; Meara, J R; Murphy, M F G

    2013-01-01

    We conducted a large record-based case-control study testing associations between childhood cancer and natural background radiation. Cases (27,447) born and diagnosed in Great Britain during 1980-2006 and matched cancer-free controls (36,793) were from the National Registry of Childhood Tumours. Radiation exposures were estimated for mother's residence at the child's birth from national databases, using the County District mean for gamma rays, and a predictive map based on domestic measurements grouped by geological boundaries for radon. There was 12% excess relative risk (ERR) (95% CI 3, 22; two-sided P=0.01) of childhood leukaemia per millisievert of cumulative red bone marrow dose from gamma radiation; the analogous association for radon was not significant, ERR 3% (95% CI -4, 11; P=0.35). Associations for other childhood cancers were not significant for either exposure. Excess risk was insensitive to adjustment for measures of socio-economic status. The statistically significant leukaemia risk reported in this reasonably powered study (power ~50%) is consistent with high-dose rate predictions. Substantial bias is unlikely, and we cannot identify mechanisms by which confounding might plausibly account for the association, which we regard as likely to be causal. The study supports the extrapolation of high-dose rate risk models to protracted exposures at natural background exposure levels.

  2. A record-based case-control study of natural background radiation and the incidence of childhood leukaemia and other cancers in Great Britain during 1980–2006

    PubMed Central

    Kendall, Gerald M.; Little, Mark P.; Wakeford, Richard; Bunch, Kathryn J.; Miles, Jon C.H.; Vincent, Timothy J.; Meara, Jill R.; Murphy, Michael F.G.

    2014-01-01

    We conducted a large record-based case-control study testing associations between childhood cancer and natural background radiation. Cases (27 447) born and diagnosed in Great Britain during 1980–2006 and matched cancer-free controls (36 793) were from the National Registry of Childhood Tumours. Radiation exposures were estimated for mother’s residence at the child’s birth from national databases, using the County District mean for gamma-rays, and a predictive map based on domestic measurements grouped by geological boundaries for radon. There was 12% excess relative risk (95% CI 3, 22; 2-sided p=0.01) of childhood leukaemia per millisievert of cumulative red-bone-marrow dose from gamma-radiation; the analogous association for radon was not significant, excess relative risk 3% (95% CI −4, 11; p=0.35). Associations for other childhood cancers were not significant for either exposure. Excess risk was insensitive to adjustment for measures of socio-economic status. The statistically significant leukaemia risk reported in this reasonably-powered study (power ~50%) is consistent with high dose-rate predictions. Substantial bias is unlikely, and we cannot identify mechanisms by which confounding might plausibly account for the association, which we regard as likely to be causal. The study supports the extrapolation of high dose-rate risk models to protracted exposures at natural background exposure levels. PMID:22766784

  3. Of the necessity of knowledge of the natural pedo-geochemical background content in the evaluation of the contamination of soils by trace elements.

    PubMed

    Baize, D; Sterckeman, T

    2001-01-08

    In order to evaluate the contamination of the Dornach (Switzerland) site within the framework of the CEEM-Soil project, each participating team was allowed to take a maximum of 15 samples. The French team's sampling was organized in such a way as to answer the following questions: (i) what is the natural concentration of the soils at this site (local pedo-geochemical background content)?; (ii) what are the levels of Cd, Cu, Pb and Zn contamination of the soil?; (iii) what is the depth reached by the surface contamination that is derived from atmospheric fallout?; (iv) how is the contamination spread along the longest axis of the area under study? The relationships between total Fe and the trace metals have allowed local variations in the natural pedo-geochemical background content to be detected and thus permitted the anthropogenic contamination to be estimated. There would appear to be a low level of Pb contamination over all the site investigated (an increase of the order of 5-10 mg kg(-1) on the background level), limited to the surface humus-bearing layers. There is also a significant contamination by Cu over all of the site (an increase of the order of 30-40 mg kg(-1)). This contamination has remained in the surface horizons (0-20 cm). Very high Zn and Cd concentrations have been found in the four surface (0-4 cm) and deep horizons (15-70 cm) taken under the forest and very much lower values in the samples taken from cultivated soils. The most likely explanation is an unequal inheritance between the upper part of the site (wooded with thinner very clayey soils) and the lower cultivated part of the site (with thicker less clayey soils developed in a loamy material). For various reasons, it seems unlikely that a contamination of the wooded part should be so much higher than the cultivated part due to the interception of atmospheric dust by the trees. The local pedo-geochemical background Cd and Zn content of the upper wooded part proved to be clearly higher than

  4. A Career Approach to Natural Resource Management in Wildlife and Recreation. Final Report.

    ERIC Educational Resources Information Center

    Barrett, Leverne A.; Mack, Rodney P.

    The "Career Approach to Natural Resource Management in Wildlife and Recreation" program has completed its second year at Conrad Weiser High School in Robesonia, Pennsylvania. It is a vocational natural resources course designed to prepare workers in wildlife and recreation management, with strong emphasis on field study and/or…

  5. How to Use Historical Approach to Teach Nature of Science in Chemistry Education?

    ERIC Educational Resources Information Center

    Tolvanen, Simo; Jansson, Jan; Vesterinen, Veli-Matti; Aksela, Maija

    2014-01-01

    Successful implementation of historical approach to teach nature of science (NOS) requires suitable curriculum material. Several research and development projects have produced lesson plans for science teachers. 25 lesson plans from four different projects involved in creating curriculum material utilizing historical approach in chemistry…

  6. Psychological linguistics: A natural science approach to the study of language interactions

    PubMed Central

    Bijou, Sidney W.; Umbreit, John; Ghezzi, Patrick M.; Chao, Chia-Chen

    1986-01-01

    Kantor's theoretical analysis of “psychological linguistics” offers a natural science approach to the study of linguistic behavior and interactions. This paper includes brief descriptions of (a) some of the basic assumptions of the approach, (b) Kantor's conception of linguistic behavior and interactions, (c) a compatible research method and sample research data, and (d) some areas of research and application. PMID:22477507

  7. Teaching Nature of Science to Pre-Service Early Childhood Teachers through an Explicit Reflective Approach

    ERIC Educational Resources Information Center

    Cil, Emine

    2014-01-01

    In this study, fifteen pre-service early childhood teachers' views of nature of science (NOS) were analysed. The student teachers took a course where NOS was taught via explicit reflective approach. The explicit reflective approach advocates that goal of improving students' NOS views should be planned for instead of being anticipated as…

  8. Learning Nature of Science Concepts through a Research Apprenticeship Program: A Comparative Study of Three Approaches

    ERIC Educational Resources Information Center

    Burgin, Stephen R.; Sadler, Troy D.

    2016-01-01

    The merits of three approaches (explicit, reflective and implicit) to Nature of Science (NOS) teaching and learning in the context of a summer research experience on high school student participants' NOS ideas were explored in this study. The effectiveness of explicit over implicit approaches has been demonstrated in school contexts, but less…

  9. Learning Nature of Science Concepts through a Research Apprenticeship Program: A Comparative Study of Three Approaches

    ERIC Educational Resources Information Center

    Burgin, Stephen R.; Sadler, Troy D.

    2016-01-01

    The merits of three approaches (explicit, reflective and implicit) to Nature of Science (NOS) teaching and learning in the context of a summer research experience on high school student participants' NOS ideas were explored in this study. The effectiveness of explicit over implicit approaches has been demonstrated in school contexts, but less…

  10. How to Use Historical Approach to Teach Nature of Science in Chemistry Education?

    ERIC Educational Resources Information Center

    Tolvanen, Simo; Jansson, Jan; Vesterinen, Veli-Matti; Aksela, Maija

    2014-01-01

    Successful implementation of historical approach to teach nature of science (NOS) requires suitable curriculum material. Several research and development projects have produced lesson plans for science teachers. 25 lesson plans from four different projects involved in creating curriculum material utilizing historical approach in chemistry…

  11. The Inextricable Axis Of Targeted Diagnostic Imaging And Therapy: An Immunological Natural History Approach

    PubMed Central

    Cope, FO; Abbruzzese, B; Sanders, J; Metz, W; Sturms, K; Ralph, D; Blue, M; Zhang, J; Bracci, P; Bshara, W; Behr, S; Maurer, T; Beverly, A; Blay, B; Damughatla, A; Larsen, M; Mountain, C; Neylon, E; Parcel, K; Raghuraman, K; Ricks, K; Rose, L; Sivakumar, A; Streck, N; Wang, B; Wasco, C; Williams, A; McGrath, M

    2016-01-01

    Summary In considering the challenges of approaches to clinical imaging, we are faced with choices that sometimes are impacted by rather dogmatic notions about what is a better or worse technology to achieve the most useful diagnostic image for the patient. For example, is PET or SPECT most useful in imaging any particular disease dissemination? The dictatorial approach would be to choose PET, all other matters being equal. But is such a totalitarian attitude toward imaging selection still valid? In the face of new receptor targeted SPECT agents one must consider the remarkable specificity and sensitivity of these agents. 99mTc-Tilmanocept is one of the newest of these agents, now approved for guiding sentinel node biopsy (SLNB) in several solid tumors. Tilmanocept has a Kd of 3×10−11 M, and it specificity for the CD206 receptor is unlike any other agent to date. This coupled with a number of facts, that specific disease-associated macrophages express this receptor (100 to 150 thousand receptors), the receptor has multiple binding sites for tilmanocept (>2 sites per receptor) and that these receptors are recycled every 15 minutes to bind more tilmanocept (acting as intracellular “drug compilers” of tilmanocept into non-degraded vesicles), give serious pause as to how we select our approaches to diagnostic imaging. Clinically, the size of SLNs varies greatly, some, anatomically, below the machine resolution of SPECT. Yet, with tilmanocept targeting, the SLNs are highly visible with macrophages stably accruing adequate 99mTc-tilmanocept counting statistics, as high target-to-background ratios can compensate for spatial resolution blurring. Importantly, it may be targeted imaging agents per se, again such as tilmanocept, which may significantly shrink any perceived chasm between the imaging technologies and anchor the diagnostic considerations in the targeting and specificity of the agent rather than any lingering dogma about the hardware as the basis for

  12. The inextricable axis of targeted diagnostic imaging and therapy: An immunological natural history approach.

    PubMed

    Cope, Frederick O; Abbruzzese, Bonnie; Sanders, James; Metz, Wendy; Sturms, Kristyn; Ralph, David; Blue, Michael; Zhang, Jane; Bracci, Paige; Bshara, Wiam; Behr, Spencer; Maurer, Toby; Williams, Kenneth; Walker, Joshua; Beverly, Allison; Blay, Brooke; Damughatla, Anirudh; Larsen, Mark; Mountain, Courtney; Neylon, Erin; Parcel, Kaeli; Raghuraman, Kapil; Ricks, Kevin; Rose, Lucas; Sivakumar, Akhilesh; Streck, Nicholas; Wang, Bryan; Wasco, Christopher; Williams, Amifred; McGrath, Michael

    2016-03-01

    In considering the challenges of approaches to clinical imaging, we are faced with choices that sometimes are impacted by rather dogmatic notions about what is a better or worse technology to achieve the most useful diagnostic image for the patient. For example, is PET or SPECT most useful in imaging any particular disease dissemination? The dictatorial approach would be to choose PET, all other matters being equal. But is such a totalitarian attitude toward imaging selection still valid? In the face of new receptor targeted SPECT agents one must consider the remarkable specificity and sensitivity of these agents. (99m)Tc-Tilmanocept is one of the newest of these agents, now approved for guiding sentinel node biopsy (SLNB) in several solid tumors. Tilmanocept has a Kd of 3×10(-11)M, and it specificity for the CD206 receptor is unlike any other agent to date. This coupled with a number of facts, that specific disease-associated macrophages express this receptor (100 to 150 thousand receptors), that the receptor has multiple binding sites for tilmanocept (>2 sites per receptor) and that these receptors are recycled every 15 min to bind more tilmanocept (acting as intracellular "drug compilers" of tilmanocept into non-degraded vesicles), gives serious pause as to how we select our approaches to diagnostic imaging. Clinically, the size of SLNs varies greatly, some, anatomically, below the machine resolution of SPECT. Yet, with tilmanocept targeting, the SLNs are highly visible with macrophages stably accruing adequate (99m)Tc-tilmanocept counting statistics, as high target-to-background ratios can compensate for spatial resolution blurring. Importantly, it may be targeted imaging agents per se, again such as tilmanocept, which may significantly shrink any perceived chasm between the imaging technologies and anchor the diagnostic considerations in the targeting and specificity of the agent rather than any lingering dogma about the hardware as the basis for imaging

  13. 'Natural background' soil water repellency in conifer forests of the north-western USA: Its prediction and relationship to wildfire occurrence

    USGS Publications Warehouse

    Doerr, S.H.; Woods, S.W.; Martin, D.A.; Casimiro, M.

    2009-01-01

    Soils under a wide range of vegetation types exhibit water repellency following the passage of a fire. This is viewed by many as one of the main causes for accelerated post-fire runoff and soil erosion and it has often been assumed that strong soil water repellency present after wildfire is fire-induced. However, high levels of repellency have also been reported under vegetation types not affected by fire, and the question arises to what degree the water repellency observed at burnt sites actually results from fire. This study aimed at determining 'natural background' water repellency in common coniferous forest types in the north-western USA. Mature or semi-mature coniferous forest sites (n = 81), which showed no evidence of recent fires and had at least some needle cast cover, were sampled across six states. After careful removal of litter and duff at each site, soil water repellency was examined in situ at the mineral soil surface using the Water Drop Penetration Time (WDPT) method for three sub-sites, followed by collecting near-surface mineral soil layer samples (0-3 cm depth). Following air-drying, samples were further analyzed for repellency using WDPT and contact angle (??sl) measurements. Amongst other variables examined were dominant tree type, ground vegetation, litter and duff layer depth, slope angle and aspect, elevation, geology, and soil texture, organic carbon content and pH. 'Natural background' water repellency (WDPT > 5 s) was detected in situ and on air-dry samples at 75% of all sites examined irrespective of dominant tree species (Pinus ponderosa, Pinus contorta, Picea engelmanii and Pseudotsuga menziesii). These findings demonstrate that the soil water repellency commonly observed in these forest types following burning is not necessarily the result of recent fire but can instead be a natural characteristic. The notion of a low background water repellency being typical for long-unburnt conifer forest soils of the north-western USA is

  14. Focal species and landscape "naturalness" corridor models offer complementary approaches for connectivity conservation planning

    Treesearch

    Meade Krosby; Ian Breckheimer; D. John Pierce; Peter H. Singleton; Sonia A. Hall; Karl C. Halupka; William L. Gaines; Robert A. Long; Brad H. McRae; Brian L. Cosentino; Joanne P. Schuett-Hames

    2015-01-01

    Context   The dual threats of habitat fragmentation and climate change have led to a proliferation of approaches for connectivity conservation planning. Corridor analyses have traditionally taken a focal species approach, but the landscape ‘‘naturalness’’ approach of modeling connectivity among areas of low human modification has gained popularity...

  15. Predominant anthropogenic sources and rates of atmospheric mercury accumulation in southern Ontario recorded by peat cores from three bogs: comparison with natural "background" values (past 8000 years).

    PubMed

    Givelet, Nicolas; Roos-Barraclough, Fiona; Shotyk, William

    2003-12-01

    Peat cores from three bogs in southern Ontario provide a complete, quantitative record of net rates of atmospheric Hg accumulation since pre-industrial times. For comparison with modern values, a peat core extending back 8000 years was used to quantify the natural variations in Hg fluxes for this region, and their dependence on climatic change and land use history. The net mercury accumulation rates were separated into "natural" and "excess" components by comparing the Hg/Br ratios of modern samples with the long-term, pre-anthropogenic average Hg/Br. The average background mercury accumulation rate during the pre-anthropogenic period (from 5700 years BC to 1470 AD) was 1.4 +/- 1.0 microg m(-2) per year (n = 197). The beginning of Hg contamination from anthropogenic sources dates from AD 1475 at the Luther Bog, corresponding to biomass burning for agricultural activities by Native North Americans. During the late 17th and 18th centuries, deposition of anthropogenic Hg was at least equal to that of Hg from natural sources. Anthropogenic inputs of Hg to the bogs have dominated continuously since the beginning of the 19th century. The maximum Hg accumulation rates decrease in the order Sifton Bog, in the City of London, Ontario (141 microg Hg m(-2) per year), Luther Bog in an agricultural region (89 microg Hg m(-2) per year), and Spruce Bog which is in a comparatively remote, forested region (54 microg Hg m(-2) per year). Accurate age dating of recent peat samples using the bomb pulse curve of 14C shows that the maximum rate of atmospheric Hg accumulation occurred during AD 1956 and 1959 at all sites. In these (modern) samples, the Hg concentration profiles resemble those of Pb, an element which is known to be immobile in peat bogs. The correlation between these two metals, together with sulfur, suggests that the predominant anthropogenic source of Hg (and Pb) was coal burning. While Hg accumulation rates have gone into strong decline since the late 1950's, Hg

  16. A combined approach of Kullback-Leibler divergence and background subtraction for moving object detection in thermal video

    NASA Astrophysics Data System (ADS)

    Yadav, Dileep Kumar; Singh, Karan

    2016-05-01

    In this work, a robust method for moving object detection in thermal video frames has been proposed by including Kullback-Leibler divergence (KLD) based threshold and background subtraction (BGS) technique. A trimmed-mean based background model has been developed that is capable enough to reduce noise or dynamic component of the background. This work assumed that each pixel has normally distributed. The KLD has computed between background pixel and a current pixel with the help of Gaussian mixture model. The proposed threshold is useful enough to classify the state of each pixel. The post-processing step uses morphological tool for edge linking, and then the flood-fill algorithm has applied for hole-filling, and finally the silhouette of targeted object has generated. The proposed methods run faster and have validated over various real-time based problematic thermal video sequences. In the experimental results, the average value of F1-score, area under the curve, the percentage of correct classification, Matthew's correlation coefficient show higher values whereas total error and percentage of the wrong classification show minimum values. Moreover, the proposed-1 method achieved higher accuracy and execution speed with minimum false alarm rate that has been compared with proposed-2 as well as considered peer methods in the real-time thermal video.

  17. Five C Framework: A Student-Centered Approach for Teaching Programming Courses to Students with Diverse Disciplinary Background

    ERIC Educational Resources Information Center

    Tom, Mary

    2015-01-01

    The already existing complexities of teaching and learning computer programming are increased where students are diverse in their disciplinary backgrounds, language skills, and culture. Learners experience emotional issues of anxiety, fear or boredom. Identifying opportunities for improvement and applying theoretical and empirical evidence found…

  18. Diversity in Intensive English Language Centres in South Australia: Sociocultural Approaches to Education for Students with Migrant or Refugee Backgrounds

    ERIC Educational Resources Information Center

    Due, Clemence; Riggs, Damien W.; Augoustinos, Martha

    2016-01-01

    While there is a body of research concerning the education of students with migrant or refugee backgrounds, little of this research focuses on primary school-aged children. In order to address this gap, the current paper utilises data gained from an ethnographic study to consider the challenges and opportunities associated with diverse classrooms…

  19. Diversity in Intensive English Language Centres in South Australia: Sociocultural Approaches to Education for Students with Migrant or Refugee Backgrounds

    ERIC Educational Resources Information Center

    Due, Clemence; Riggs, Damien W.; Augoustinos, Martha

    2016-01-01

    While there is a body of research concerning the education of students with migrant or refugee backgrounds, little of this research focuses on primary school-aged children. In order to address this gap, the current paper utilises data gained from an ethnographic study to consider the challenges and opportunities associated with diverse classrooms…

  20. Examination of the Cross-Battery Approach for the Cognitive Assessment of Children and Youth from Diverse Linguistic and Cultural Backgrounds

    ERIC Educational Resources Information Center

    Kranzler, John H.; Flores, Cindi G.; Coady, Maria

    2010-01-01

    Flanagan, Ortiz, and Alfonso (2007) recently developed the Culture-Language Interpretive Matrices (C-LIMs) for the cognitive assessment of children and youth from culturally and linguistically diverse backgrounds. To examine the utility of this new approach, we administered the Woodcock-Johnson Tests of Cognitive Abilities to a sample of students…

  1. Peripheral blood lymphocyte micronucleus frequencies in men from areas of Kerala, India, with high vs normal levels of natural background ionizing radiation.

    PubMed

    Karuppasamy, C V; Ramachandran, E N; Kumar, V Anil; Kumar, P R Vivek; Koya, P K M; Jaikrishan, G; Das, Birajalaxmi

    2016-04-01

    We have measured the frequencies of micronuclei (MN) in adult male individuals living in areas of the Kerala coast, southwest India, with either high (HLNRA, >1.5mGy/year) or normal levels of natural ionizing radiation (NLNRA, ≤1.5mGy/year). Blood samples were obtained from 141 individuals, 94 from HLNRA and 47 from NLNRA, aged 18-72, and were subjected to the cytokinesis-block micronucleus (CBMN) assay. An average of 1835 binucleated (BN) cells per individual were scored. The overall frequency of MN (mean±SD) was 11.7±6.7 per 1000 BN cells. The frequencies of MN in the HLNRA (11.7±6.6) and NLNRA (11.6±6.7) were not statistically significantly different (P=0.59). However, a statistically significant (P<0.001) age-dependent increase in MN frequency was observed among individuals from both HLNRA and NLNRA. No natural background radiation dose-dependent increase in MN frequency was seen. MN frequency was not influenced by tobacco smoking or chewing but it was increased among individuals consuming alcohol. Chronic low-dose radiation in the Kerala coast did not have a significant effect on MN frequency among adult men.

  2. Multi-Site Application of the Geomechanical Approach for Natural Fracture Exploration

    SciTech Connect

    R. L. Billingsley; V. Kuuskraa

    2006-03-31

    In order to predict the nature and distribution of natural fracturing, Advanced Resources Inc. (ARI) incorporated concepts of rock mechanics, geologic history, and local geology into a geomechanical approach for natural fracture prediction within mildly deformed, tight (low-permeability) gas reservoirs. Under the auspices of this project, ARI utilized and refined this approach in tight gas reservoir characterization and exploratory activities in three basins: the Piceance, Wind River and the Anadarko. The primary focus of this report is the knowledge gained on natural fractural prediction along with practical applications for enhancing gas recovery and commerciality. Of importance to tight formation gas production are two broad categories of natural fractures: (1) shear related natural fractures and (2) extensional (opening mode) natural fractures. While arising from different origins this natural fracture type differentiation based on morphology is sometimes inter related. Predicting fracture distribution successfully is largely a function of collecting and understanding the available relevant data in conjunction with a methodology appropriate to the fracture origin. Initially ARI envisioned the geomechanical approach to natural fracture prediction as the use of elastic rock mechanics methods to project the nature and distribution of natural fracturing within mildly deformed, tight (low permeability) gas reservoirs. Technical issues and inconsistencies during the project prompted re-evaluation of these initial assumptions. ARI's philosophy for the geomechanical tools was one of heuristic development through field site testing and iterative enhancements to make it a better tool. The technology and underlying concepts were refined considerably during the course of the project. As with any new tool, there was a substantial learning curve. Through a heuristic approach, addressing these discoveries with additional software and concepts resulted in a stronger set of

  3. Copy, edit, and paste: natural product approaches to biomaterials and neuroengineering.

    PubMed

    Gademann, Karl

    2015-03-17

    Progress in the chemical sciences has formed the world we live in, both on a macroscopic and on a nanoscopic scale. The last century witnessed the development of high performance materials that interact with humans on many layers, from clothing to construction, from media to medical devices. On a molecular level, natural products and their derivatives influence many biological processes, and these compounds have enormously contributed to the health and quality of living of humans. Although coatings of stone materials with oils or resins (containing natural products) have led to improved tools already millennia ago, in contrast today, natural product approaches to designer materials, that is, combining the best of both worlds, remain scarce. In this Account, we will summarize our recent research efforts directed to the generation of natural product functionalized materials, exploiting the strategy of "copy, edit, and paste with natural products". Natural products embody the wisdom of evolution, and only total synthesis is able to unlock the secrets enshrined in their molecular structure. We employ total synthesis ("copy") as a scientific approach to address problems related to molecular structure, the biosynthesis of natural products, and their bioactivity. Additionally, the fundamental desire to investigate the mechanism of action of natural products constitutes a key driver for scientific inquiry. In an emerging area of relevance to society, we have prepared natural products such as militarinone D that can stimulate neurite outgrowth and facilitate nerve regeneration. This knowledge obtained by synthetic organic chemistry on complex natural products can then be used to design structurally simplified compounds that retain the biological power of the parent natural product ("edit"). This process, sometimes referred to as function-oriented synthesis, allows obtaining derivatives with better properties, improving their chemical tractability and reducing the step count

  4. A New Approach for Estimating Background Rates of Erosion Using Concentration of Meteoric 10-Be Adhered to River Sediment: Application to the Rapidly Eroding Waipaoa Basin, New Zealand

    NASA Astrophysics Data System (ADS)

    Reusser, L. J.; Bierman, P. R.; Pavich, M.; Finkel, R.

    2007-12-01

    -day sediment yields are at least seven times higher than natural rates of sediment generation. This finding is in tight agreement with other estimates of pre-settlement sediment discharge from the Waipaoa Basin derived from middle shelf and nearby lake cores (Kettner et al., 2007; Page and Trustrum, 1997). Tributary basins (n=4) draining portions of the Waipaoa Basin dominated by landsliding in shallow soils yield an average background sediment generation rate of 106 ± 105 kg/(km2 * yr), assuming a deposition rate of 1.3 million atoms 10-Be/(cm2 * yr). Conversely, sediment shed from a basin dominated by severe gullying contains ~four times less 10-Be due to the contribution of deeply sourced material containing little or no meteoric 10-Be. Large basins to the north and south of the Waipaoa (n=3) yield similar background rates of sediment generation ranging from 0.25 to 1.6 million kg/(km2 * yr). Meteoric analysis of an additional 40 samples, as well as cross-calibration between in situ produced and meteoric 10-Be in 19 quartz-bearing samples will further test the robustness of this new approach for estimating natural rates of sediment generation and erosion.

  5. Affinity Crystallography: A New Approach to Extracting High-Affinity Enzyme Inhibitors from Natural Extracts.

    PubMed

    Aguda, Adeleke H; Lavallee, Vincent; Cheng, Ping; Bott, Tina M; Meimetis, Labros G; Law, Simon; Nguyen, Nham T; Williams, David E; Kaleta, Jadwiga; Villanueva, Ivan; Davies, Julian; Andersen, Raymond J; Brayer, Gary D; Brömme, Dieter

    2016-08-26

    Natural products are an important source of novel drug scaffolds. The highly variable and unpredictable timelines associated with isolating novel compounds and elucidating their structures have led to the demise of exploring natural product extract libraries in drug discovery programs. Here we introduce affinity crystallography as a new methodology that significantly shortens the time of the hit to active structure cycle in bioactive natural product discovery research. This affinity crystallography approach is illustrated by using semipure fractions of an actinomycetes culture extract to isolate and identify a cathepsin K inhibitor and to compare the outcome with the traditional assay-guided purification/structural analysis approach. The traditional approach resulted in the identification of the known inhibitor antipain (1) and its new but lower potency dehydration product 2, while the affinity crystallography approach led to the identification of a new high-affinity inhibitor named lichostatinal (3). The structure and potency of lichostatinal (3) was verified by total synthesis and kinetic characterization. To the best of our knowledge, this is the first example of isolating and characterizing a potent enzyme inhibitor from a partially purified crude natural product extract using a protein crystallographic approach.

  6. Natural approaches to prevention and treatment of infections of the lower urinary tract.

    PubMed

    Head, Kathleen A

    2008-09-01

    Infections of the lower urinary tract are common occurrences in young women, during pregnancy, and in peri- and postmenopausal women. Because of the chronic nature of urinary tract infections (UTIs) and the potential for antibiotic resistance, a natural approach to prevention and treatment is desirable. Clinical research suggests the best natural options for long-term prevention include cranberry, mannose, and probiotics. Botanicals that can be effective at the first sign of an infection and for short-term prophylaxis include berberine and uva ursi. Estriol cream and vitamins A and C have also been shown to prevent UTIs, while potassium salts can alkalinize the urine and reduce dysuria.

  7. Natural Resource Assessment: An Approach to Science Based Planning in National Parks

    NASA Astrophysics Data System (ADS)

    Mahan, Carolyn G.; Vanderhorst, James P.; Young, John A.

    2009-06-01

    We conducted a natural resource assessment at two national parks, New River Gorge National River and Shenandoah National Park, to help meet the goals of the Natural Resource Challenge—a program to help strengthen natural resource management at national parks. We met this challenge by synthesizing and interpreting natural resource information for planning purposes and we identified information gaps and natural significance of resources. We identified a variety of natural resources at both parks as being globally and/or nationally significant, including large expanses of unfragmented, mixed-mesophytic forests that qualify for wilderness protection, rare plant communities, diverse assemblages of neotropical migratory birds and salamanders, and outstanding aquatic recreational resources. In addition, these parks function, in part, as ecological reserves for plants in and wildlife. With these significant natural resources in mind, we also developed a suite of natural resource management recommendations in light of increasing threats from within and outside park boundaries. We hope that our approach can provide a blueprint for natural resource conservation at publically owned lands.

  8. Natural resource assessment: an approach to science based planning in national parks

    USGS Publications Warehouse

    Mahan, C.G.; Vanderhorst, J.P.; Young, J.A.

    2009-01-01

    We conducted a natural resource assessment at two national parks, New River Gorge National River and Shenandoah National Park, to help meet the goals of the Natural Resource Challenge-a program to help strengthen natural resource management at national parks. We met this challenge by synthesizing and interpreting natural resource information for planning purposes and we identified information gaps and natural significance of resources. We identified a variety of natural resources at both parks as being globally and/or nationally significant, including large expanses of unfragmented, mixed-mesophytic forests that qualify for wilderness protection, rare plant communities, diverse assemblages of neotropical migratory birds and salamanders, and outstanding aquatic recreational resources. In addition, these parks function, in part, as ecological reserves for plants in and wildlife. With these significant natural resources in mind, we also developed a suite of natural resource management recommendations in light of increasing threats from within and outside park boundaries. We hope that our approach can provide a blueprint for natural resource conservation at publically owned lands.

  9. Natural resource assessment: an approach to science based planning in national parks.

    PubMed

    Mahan, Carolyn G; Vanderhorst, James P; Young, John A

    2009-06-01

    We conducted a natural resource assessment at two national parks, New River Gorge National River and Shenandoah National Park, to help meet the goals of the Natural Resource Challenge--a program to help strengthen natural resource management at national parks. We met this challenge by synthesizing and interpreting natural resource information for planning purposes and we identified information gaps and natural significance of resources. We identified a variety of natural resources at both parks as being globally and/or nationally significant, including large expanses of unfragmented, mixed-mesophytic forests that qualify for wilderness protection, rare plant communities, diverse assemblages of neotropical migratory birds and salamanders, and outstanding aquatic recreational resources. In addition, these parks function, in part, as ecological reserves for plants in and wildlife. With these significant natural resources in mind, we also developed a suite of natural resource management recommendations in light of increasing threats from within and outside park boundaries. We hope that our approach can provide a blueprint for natural resource conservation at publically owned lands.

  10. Estimation of the radiological background and dose assessment in areas with naturally occurring uranium geochemical anomalies--a case study in the Iberian Massif (Central Portugal).

    PubMed

    Pereira, A J S C; Neves, L J P F

    2012-10-01

    Naturally occurring uranium geochemical anomalies, representative of the several thousand recognized in the Portuguese section of the Iberian Massif and outcropping in three target areas with a total of a few thousand square metres, were subjected to a detailed study (1:1000 scale) to evaluate the radiological health-risk on the basis of a dose assessment. To reach this goal some radioactive isotopes from the uranium, thorium and potassium radioactive series were measured in 52 samples taken from different environmental compartments: soils, stream sediments, water, foodstuff (vegetables) and air; external radiation was also measured through a square grid of 10×10 m, with a total of 336 measurements. The results show that some radioisotopes have high activities in all the environmental compartments as well as a large variability, namely for those of the uranium decay chain, which is a common situation in the regional geological setting. Isotopic disequilibrium is also common and led to an enrichment of several isotopes in the different pathways, as is the case of (226)Ra; maximum values of 1.76 Bq L(-1) (water), 986 Bq kg(-1) (soils) and 18.9 Bq kg(-1) (in a turnip sample) were measured. On the basis of a realistic scenario combined with the experimental data, the effective dose from exposure to ionizing radiation for two groups of the population (rural and urban) was calculated; the effective dose is variable between 8.0 and 9.5 mSv year(-1), which is 3-4 times higher than the world average. Thus, the radiological health-risk for these populations could be significant and the studied uranium anomalies must be taken into account in the assessment of the geochemical background. The estimated effective dose can also be used as typical of the background of the Beiras uranium metalogenetic province and therefore as a "benchmark" in the remediation of the old uranium mining sites. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. S-matrix decomposition, natural reaction channels, and the quantum transition state approach to reactive scattering

    NASA Astrophysics Data System (ADS)

    Manthe, Uwe; Ellerbrock, Roman

    2016-05-01

    A new approach for the quantum-state resolved analysis of polyatomic reactions is introduced. Based on the singular value decomposition of the S-matrix, energy-dependent natural reaction channels and natural reaction probabilities are defined. It is shown that the natural reaction probabilities are equal to the eigenvalues of the reaction probability operator [U. Manthe and W. H. Miller, J. Chem. Phys. 99, 3411 (1993)]. Consequently, the natural reaction channels can be interpreted as uniquely defined pathways through the transition state of the reaction. The analysis can efficiently be combined with reactive scattering calculations based on the propagation of thermal flux eigenstates. In contrast to a decomposition based straightforwardly on thermal flux eigenstates, it does not depend on the choice of the dividing surface separating reactants from products. The new approach is illustrated studying a prototypical example, the H + CH4 → H2 + CH3 reaction. The natural reaction probabilities and the contributions of the different vibrational states of the methyl product to the natural reaction channels are calculated and discussed. The relation between the thermal flux eigenstates and the natural reaction channels is studied in detail.

  12. S-matrix decomposition, natural reaction channels, and the quantum transition state approach to reactive scattering.

    PubMed

    Manthe, Uwe; Ellerbrock, Roman

    2016-05-28

    A new approach for the quantum-state resolved analysis of polyatomic reactions is introduced. Based on the singular value decomposition of the S-matrix, energy-dependent natural reaction channels and natural reaction probabilities are defined. It is shown that the natural reaction probabilities are equal to the eigenvalues of the reaction probability operator [U. Manthe and W. H. Miller, J. Chem. Phys. 99, 3411 (1993)]. Consequently, the natural reaction channels can be interpreted as uniquely defined pathways through the transition state of the reaction. The analysis can efficiently be combined with reactive scattering calculations based on the propagation of thermal flux eigenstates. In contrast to a decomposition based straightforwardly on thermal flux eigenstates, it does not depend on the choice of the dividing surface separating reactants from products. The new approach is illustrated studying a prototypical example, the H + CH4 → H2 + CH3 reaction. The natural reaction probabilities and the contributions of the different vibrational states of the methyl product to the natural reaction channels are calculated and discussed. The relation between the thermal flux eigenstates and the natural reaction channels is studied in detail.

  13. Applying a Methodological Approach to the Development of a Natural Interaction System

    NASA Astrophysics Data System (ADS)

    Del Valle-Agudo, David; Rivero-Espinosa, Jessica; Calle-Gómez, Francisco Javier; Cuadra-Fernández, Dolores

    This work describes the methodology used to design a Natural Interaction System for guiding services. A national research project was the framework where the approach was applied. The aim of that system is interacting with clients of a hotel for providing diverse services. Apart from the description of the methodology, a case study is added to the paper in order to outline strengths of the approach, and limits that should lead to future research.

  14. Nature

    NASA Astrophysics Data System (ADS)

    Heinhorst, Sabine; Cannon, Gordon

    1997-01-01

    The fact that two of the original articles by this year's Nobel laureates were published in Nature bears witness to the pivotal role of this journal in documenting pioneering discoveries in all areas of science. The prize for Physiology or Medicine was awarded to immunologists Peter C. Doherty (University of Tennessee) and Rolf M. Zinkernagel (University of Zurich, Switzerland), honoring work that, in the 1970s, laid the foundation for our current understanding of the way in which our immune system differentiates between healthy cells and virus-infected ones that are targeted for destruction (p 465 in the October 10 issue of vol. 383). Three researchers share the Chemistry award for their discovery of C60 buckminsterfullerenes. The work by Robert Curl, Richard Smalley (both at Rice University), and Harry Kroto (University of Sussex, UK) has led to a burst of new approaches to materials development and in carbon chemistry (p 561 of the October 17 issue of vol. 383). This year's Nobel prize in physics went to three U.S. researchers, Douglas Osheroff (Stanford University) and David M. Lee and Robert C. Richardson (Cornell University), who were honored for their work on superfluidity, a frictionless liquid state, of supercooled 3He (p 562 of the October 17 issue of vol. 383).

  15. Approach of background metric expansion to a new metric ansatz for gauged and ungauged Kaluza-Klein supergravity black holes

    NASA Astrophysics Data System (ADS)

    Wu, Shuang-Qing; Wang, He

    2015-05-01

    In a previous paper [S. Q. Wu, Phys. Rev. D 83, 121502(R) (2011)], a new kind of metric ansatz was found to fairly describe all already-known black hole solutions in the ungauged Kaluza-Klein (KK) supergravity theories. That metric ansatz somewhat resembles the famous Kerr-Schild (KS) form, but it is different from the KS one in two distinct aspects. That is, apart from a global conformal factor, the metric ansatz can be written as a vacuum background spacetime plus a "perturbation" modification term, the latter of which is associated with a timelike geodesic vector field rather than a null geodesic congruence in the usual KS ansatz. Replacing the flat vacuum background metric by the (anti-)de Sitter [(A)dS] spacetime, the general rotating charged KK-(A)dS black hole solutions in all higher dimensions have been successfully constructed and put into a unified form. In this paper, we shall study this novel metric ansatz in detail, aiming at achieving some inspiration as to the construction of rotating charged AdS black holes with multiple charges in other gauged supergravity theories. We find that the traditional perturbation expansion method often successfully used in the KS form is no longer useful in our new ansatz, since here no good parameter can be chosen as a suitable perturbation indicator. In order to investigate the metric properties of the general KK-AdS solutions, in this paper we devise a new effective method, dubbed the background metric expansion method, which can be thought of as a generalization of the perturbation expansion method, to deal with the Lagrangian and all equations of motion. In addition to two previously known conditions, namely the timelike and geodesic properties of the vector, we get three additional constraints via contracting the Maxwell and Einstein equations once or twice with this timelike geodesic vector. In particular, we find that these are a simpler set of sufficient conditions to determine the vector and the dilaton scalar

  16. Environmental geochemistry of shale-hosted Ag-Pb-Zn massive sulfide deposits in northwest Alaska: Natural background concentrations of metals in water from mineralized areas

    USGS Publications Warehouse

    Kelley, K.D.; Taylor, C.D.

    1997-01-01

    Red Dog, Lik and Drenchwater are shale-hosted stratiform Ag-Pb-Zn massive sulfide deposits in the northwestern Brooks Range. Natural background concentrations of metals in waters from the undisturbed (unmined) Drenchwater prospect and Lik deposit were compared to pre-mining baseline studies conducted at Red Dog. The primary factors affecting water chemistry are the extent of exposure of the deposits, the grade of mineralization, the presence of carbonate reeks in the section, and the proportion of Fe-sulfide in the ore. Surface water samples from the Drenchwater prospect, which has pyrite-dominant mineralization exposed in outcrop, have pH values as low as 2.8 and high dissolved concentrations of metals including as much as 95 mg 1-1 Al, 270 mg 1-1 Fe, 8 ??1-1 Cd, 10 ??1-1 Pb, and 2600 ??1-1 Zn, with As up to 26 ??g1-1. Surface waters from the Red Dog deposit prior to mining were also acidic and metal-rich, however, dissolved metal concentrations in Red Dog waters were many times greater. The higher metal concentrations in Red Dog waters reflect the high Zn grades and the abundant sphalerite, pyrite, and galena that were present in outcrop prior to mining. In contrast, despite significant mineralization at the Lik deposit, carbonate rocks in the section buffer the system, resulting in less acidic, mostly near-neutral pH values with low concentrations of most metals except Zn.

  17. A New Computerized Approach for Teaching the Nature of Membrane Potentials.

    ERIC Educational Resources Information Center

    Vazquez, Jesus

    1991-01-01

    Presents a BASIC program that can be useful in explaining physicochemical phenomena underlying the generation of membrane potential in excitable cells. Its simplicity allows students to understand the nature of these processes through a direct, hands-on approach. Also, the simulated voltage and concentration kinetics agree well with those…

  18. Traditional, Natural, and TPR Approaches to ESL: A Study of Japanese Students.

    ERIC Educational Resources Information Center

    Furuhata, Hamako

    1999-01-01

    Reports a study of Japanese students' perception of traditional methods versus the natural approach and total physical response (TPR) methods for learning English, and their preferred styles of learning. Subjects were Japanese students attending intensive language schools in the U.S. Students generally preferred innovative methods, such as…

  19. The Nature of Elementary Student Science Discourse in the Context of the Science Writing Heuristic Approach

    ERIC Educational Resources Information Center

    Cavagnetto, Andy; Hand, Brian M.; Norton-Meier, Lori

    2010-01-01

    This case study aimed to determine the nature of student interactions in small groups in an elementary classroom utilizing the Science Writing Heuristic approach. Fifth grade students were audio-recorded over four units of study while working in small groups to generate knowledge claims after conducting student-directed investigations. Analysis…

  20. Traditional, Natural, and TPR Approaches to ESL: A Study of Japanese Students.

    ERIC Educational Resources Information Center

    Furuhata, Hamako

    1999-01-01

    Reports a study of Japanese students' perception of traditional methods versus the natural approach and total physical response (TPR) methods for learning English, and their preferred styles of learning. Subjects were Japanese students attending intensive language schools in the U.S. Students generally preferred innovative methods, such as…

  1. Understanding the Nature of Science and Scientific Progress: A Theory-Building Approach

    ERIC Educational Resources Information Center

    Chuy, Maria; Scardamalia, Marlene; Bereiter, Carl; Prinsen, Fleur; Resendes, Monica; Messina, Richard; Hunsburger, Winifred; Teplovs, Chris; Chow, Angela

    2010-01-01

    In 1993 Carey and Smith conjectured that the most promising way to boost students' understanding of the nature of science is a "theory-building approach to teaching about inquiry." The research reported here tested this conjecture by comparing results from two Grade 4 classrooms that differed in their emphasis on and technological…

  2. A New Computerized Approach for Teaching the Nature of Membrane Potentials.

    ERIC Educational Resources Information Center

    Vazquez, Jesus

    1991-01-01

    Presents a BASIC program that can be useful in explaining physicochemical phenomena underlying the generation of membrane potential in excitable cells. Its simplicity allows students to understand the nature of these processes through a direct, hands-on approach. Also, the simulated voltage and concentration kinetics agree well with those…

  3. Understanding Nature-Related Behaviors among Children through a Theory of Reasoned Action Approach

    ERIC Educational Resources Information Center

    Gotch, Chad; Hall, Troy

    2004-01-01

    The Theory of Reasoned Action has proven to be a valuable tool for predicting and understanding behavior and, as such, provides a potentially important basis for environmental education program design. This study used a Theory of Reasoned Action approach to examine a unique type of behavior (nature-related activities) and a unique population…

  4. Non-Human Nature and the Ecosystem Approach: The Limits of Anthropocentrism in Great Lakes Management.

    ERIC Educational Resources Information Center

    Bell, Anne

    1994-01-01

    The ecosystem approach is a management philosophy in which humans participate in the natural world, not dominate it. Discusses this concept with respect to the Great Lakes context, the anthropocentric argument, sustainable development, and integrating economy and environment. (Contains 52 references.) (MDH)

  5. Microcomputer-Based Approaches for Preventing Drug and Alcohol Abuse Among Adolescents from Ethnic-Racial Minority Backgrounds.

    PubMed

    Moncher, Michael S; Parms, Clifford A; Orlandi, Mario A; Schinke, Steven P; Miller, Samuel O; Palleja, Josephine; Schinke, Mary B

    1989-01-01

    This study was designed to empirically assess the potential of microcomputer-based intervention with black adolescents from economically disadvantaged backgrounds. Subjects were 26, 11 through 14-year-old black females and males recruited from three boroughs in New York City. A sample task was administered via microcomputer system followed by a postintervention measurement battery. Observational measures were also employed to assess interactional variables. Subjects' attitudes toward educational content in general, and toward drug and alcohol information delivery in particular, appeared to be a significant intervening variable that could alter the overall efficacy of computer-delivered interventions. Both observational and postintervention measures indicated an overall positive subject response to computer-administered instruction. In contrast, however, respondents indicated a negative response to microcomputer delivery of drug and alcohol related materials. Results of the experiment are discussed along with rationales and future research directions.

  6. A new approach to the definition of seroconversion following vaccination in a population with high background antibody concentrations.

    PubMed

    Chandramohan, Daniel; Coleman, Paul; Nelson, Chris; Greenwood, Brian

    2007-09-03

    Licensure of meningitis vaccines is increasingly being made on the basis of safety and immunogenicity. For meningococcal vaccines, a measure of immunogenicity is seroconversion, usually defined as a four-fold increase in rSBA titre. However, this definition is likely to underestimate seroconversion in settings with high background immunity. Using data from a study of the immunogenicity of meningococcal polysaccharide vaccines undertaken in Ghana, a logistic regression model to estimate the probability of seroconversion as a function of pre-vaccination titre has been developed. The seroconversion rate (91%) based on a variable-fold increase in rSBA titre derived from the model was a more plausible estimate of immunogenicity than the seroconversion rate (32%) based on the fixed four-fold increase in rSBA.

  7. Microcomputer-Based Approaches for Preventing Drug and Alcohol Abuse Among Adolescents from Ethnic-Racial Minority Backgrounds

    PubMed Central

    Moncher, Michael S.; Parms, Clifford A.; Orlandi, Mario A.; Schinke, Steven P.; Miller, Samuel O.; Palleja, Josephine; Schinke, Mary B.

    2006-01-01

    This study was designed to empirically assess the potential of microcomputer-based intervention with black adolescents from economically disadvantaged backgrounds. Subjects were 26, 11 through 14-year-old black females and males recruited from three boroughs in New York City. A sample task was administered via microcomputer system followed by a postintervention measurement battery. Observational measures were also employed to assess interactional variables. Subjects’ attitudes toward educational content in general, and toward drug and alcohol information delivery in particular, appeared to be a significant intervening variable that could alter the overall efficacy of computer-delivered interventions. Both observational and postintervention measures indicated an overall positive subject response to computer-administered instruction. In contrast, however, respondents indicated a negative response to microcomputer delivery of drug and alcohol related materials. Results of the experiment are discussed along with rationales and future research directions. PMID:17387376

  8. A Time-Critical Adaptive Approach for Visualizing Natural Scenes on Different Devices

    PubMed Central

    Dong, Tianyang; Liu, Siyuan; Xia, Jiajia; Fan, Jing; Zhang, Ling

    2015-01-01

    To automatically adapt to various hardware and software environments on different devices, this paper presents a time-critical adaptive approach for visualizing natural scenes. In this method, a simplified expression of a tree model is used for different devices. The best rendering scheme is intelligently selected to generate a particular scene by estimating the rendering time of trees based on their visual importance. Therefore, this approach can ensure the reality of natural scenes while maintaining a constant frame rate for their interactive display. To verify its effectiveness and flexibility, this method is applied in different devices, such as a desktop computer, laptop, iPad and smart phone. Applications show that the method proposed in this paper can not only adapt to devices with different computing abilities and system resources very well but can also achieve rather good visual realism and a constant frame rate for natural scenes. PMID:25723177

  9. Models in physics teaching: an approach to highlight the nature of knowledge

    NASA Astrophysics Data System (ADS)

    Botelho Kneubil, Fabiana

    2016-11-01

    In this work we show an approach based on models, for an usual subject in an introductory physics course, in order to foster discussions on the nature of physical knowledge. The introduction of elements of the nature of knowledge in physics lessons has been emphasised by many educators and one uses the case of metals to show the theoretical and phenomenological dimensions of physics. The discussion is made by means of four questions whose answers cannot be reached neither for theoretical elements nor experimental measurements. Between these two dimensions it is necessary to realise a series of reasoning steps to deepen the comprehension of microscopic concepts, such as electrical resistivity, drift velocity and free electrons. When this approach is highlighted, beyond the physical content, aspects of its nature become explicit and may improve the structuring of knowledge for learners on this subject.

  10. A Family Resemblance Approach to the Nature of Science for Science Education

    NASA Astrophysics Data System (ADS)

    Irzik, Gürol; Nola, Robert

    2011-07-01

    Although there is universal consensus both in the science education literature and in the science standards documents to the effect that students should learn not only the content of science but also its nature, there is little agreement about what that nature is. This led many science educators to adopt what is sometimes called "the consensus view" about the nature of science (NOS), whose goal is to teach students only those characteristics of science on which there is wide consensus. This is an attractive view, but it has some shortcomings and weaknesses. In this article we present and defend an alternative approach based on the notion of family resemblance. We argue that the family resemblance approach is superior to the consensus view in several ways, which we discuss in some detail.

  11. 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.

  12. Stability Assessment of Natural Caves Using Empirical Approaches and Rock Mass Classifications

    NASA Astrophysics Data System (ADS)

    Jordá-Bordehore, L.

    2017-08-01

    The stability of underground voids such as caves can be assessed, in an initial approximation, by geomechanical classifications such as the Barton Q index. From a geomechanical viewpoint, the stability of 137 large span natural caves was analyzed herein. The caves were graphically represented based on existing tunnel and underground graphs, according to width and rock quality index Q. Many natural caves analyzed by a tunnel-type engineering approach could result as apparently unstable when represented in empirical existing graphics and would require reinforcements incompatible with speleothems and large chamber heights. A new graph and equation are proposed herein for the maximum span, for the exclusive case of caves, resulting in a reliable representation of large stable natural caves. The main contribution is a new stability chart for natural caves, consisting of two zones: a zone where stable caves are represented and a zone where unstable caves and collapsed caves are located.

  13. A direct approach for instantaneous 3D density field reconstruction from background-oriented schlieren (BOS) measurements

    NASA Astrophysics Data System (ADS)

    Nicolas, F.; Todoroff, V.; Plyer, A.; Le Besnerais, G.; Donjat, D.; Micheli, F.; Champagnat, F.; Cornic, P.; Le Sant, Y.

    2016-01-01

    We present a new numerical method for reconstruction of instantaneous density volume from 3D background-oriented schlieren (3DBOS) measurements, with a validation on a dedicated flexible experimental BOS bench. In contrast to previous works, we use a direct formulation where density is estimated from measured deviation fields without the intermediate step of density gradient reconstruction. Regularization techniques are implemented to deal with the ill-posed problem encountered. The resulting high-dimensional optimization is conducted by conjugate gradient techniques. A parallel algorithm, implemented on graphics processing unit, helps to speed up the calculation. The resulting software is validated on synthetic BOS images of a 3D density field issued from a numerical simulation. Then, we describe a dedicated 3DBOS experimental facility which has been built to study various BOS settings and to assess the performance of the proposed numerical reconstruction process. Results on various datasets illustrate the potential of the method for flow characterization and measurement in real-world conditions.

  14. Inversion Approach to Validate Mercury Emissions Based on Background Air Monitoring at the High Altitude Research Station Jungfraujoch (3580 m).

    PubMed

    Denzler, Basil; Bogdal, Christian; Henne, Stephan; Obrist, Daniel; Steinbacher, Martin; Hungerbühler, Konrad

    2017-03-07

    The reduction of emissions of mercury is a declared aim of the Minamata Convention, a UN treaty designed to protect human health and the environment from adverse effects of mercury. To assess the effectiveness of the convention in the future, better constraints about the current mercury emissions is a premise. In our study, we applied a top-down approach to quantify mercury emissions on the basis of atmospheric mercury measurements conducted at the remote high altitude monitoring station Jungfraujoch, Switzerland. We established the source-receptor relationships and by the means of atmospheric inversion we were able to quantify spatially resolved European emissions of 89 ± 14 t/a for elemental mercury. Our European emission estimate is 17% higher than the bottom-up emission inventory, which is within stated uncertainties. However, some regions with unexpectedly high emissions were identified. Stationary combustion, in particular in coal-fired power plants, is found to be the main responsible sector for increased emission estimates. Our top-down approach, based on measurements, provides an independent constraint on mercury emissions, helps to improve and refine reported emission inventories, and can serve for continued assessment of future changes in emissions independent from bottom-up inventories.

  15. Development and application of an ecosystem management approach for protected natural areas

    NASA Astrophysics Data System (ADS)

    Lajeunesse, Denyse; Domon, Gérald; Drapeau, Pierre; Cogliastro, Alain; Bouchard, André

    1995-07-01

    Preservation of small natural areas is not in itself a sufficient measure to maintain the integrity of the ecosystems for which they were initially set aside. Intense pressure from recreational use is just one of the many human-caused stresses that may degrade natural areas. Therefore, land-use planning and management from an ecological perspective is necessary to assess, ensure, and in some cases increase, the ecological integrity of protected natural areas. An ecosystem management approach for small protected natural areas with high recreational use is presented, based on three interrelated components: an ecological evaluation procedure of ecosystems, the implementation of management interventions on ecosystems, and the development of a monitoring scheme of ecosystem components. The ecological evaluation procedure combines two concepts: the biotic value of vegetation and wildlife and the abiotic fragility of the soils. This combined evaluation process results in the creation of a sensitivity map that can be used as a management tool for planners and managers. Management interventions, the second component of the management approach, are derived from concepts of ecological succession. Intentional human interventions are used to maintain the ecological integrity of ecosystems or in some cases to restore degraded sites. For the third component, only the basic principles of the monitoring program will be discussed. A pilot project in one of the Montreal urban community protected areas is presented to illustrate aspects of the proposed ecosystem management approach.

  16. Natural inflation: Particle physics models, power-law spectra for large-scale structure, and constraints from the Cosmic Background Explorer

    NASA Astrophysics Data System (ADS)

    Adams, Fred C.; Bond, J. Richard; Freese, Katherine; Frieman, Joshua A.; Olinto, Angela V.

    1993-01-01

    We discuss the particle physics basis for models of natural inflation with pseudo Nambu-Goldstone bosons and study the consequences for large-scale structure of the nonscale-invariant density fluctuation spectra that arise in natural inflation and other models. A pseudo Nambu-Goldstone boson, with a potential of the form V(φ)=Λ4[1+/-cos(φ/f)], can naturally give rise to an epoch of inflation in the early Universe, if f~MPl and Λ~MGUT. Such mass scales arise in particle physics models with a gauge group that becomes strongly interacting at the grand unified theory scale. We work out a specific particle physics example based on the multiple gaugino condensation scenario in superstring theory. We then study the cosmological evolution of and constraints upon these inflation models numerically and analytically. To obtain sufficient inflation with a probability of order 1 and a high enough post-inflation reheat temperature for baryogenesis, we require f>~0.3MPl. The primordial density fluctuation spectrum generated by quantum fluctuations in φ is a non-scale-invariant power law P(k)~kns, with ns~=1-(M2Pl/8πf2) leading to more power on large length scales than the ns=1 Harrison-Zeldovich spectrum. (For the reader primarily interested in large-scale structure, the discussion of this topic is presented in Sec. IV and is intended to be nearly self-contained.) We pay special attention to the prospects of using the enhanced power to explain the otherwise puzzling large-scale clustering of galaxies and clusters and their flows. We find that the standard cold dark matter (CDM) model with 0<~ns<~0.6 could in principle explain these data. However, the microwave background anisotropies recently detected by the Cosmic Background Explorer (COBE) imply such low primordial amplitudes for these CDM models (that is, bias factors b8>~2 for ns<~0.6) that galaxy formation would occur too late to be viable and the large-scale galaxy velocities would be too small. In fact, combining the

  17. Exploring the background features of acidic and basic air pollutants around an industrial complex using data mining approach.

    PubMed

    Chen, Ho-Wen; Tsai, Ching-Tsan; She, Chin-Wen; Lin, Yo-Chen; Chiang, Chow-Feng

    2010-11-01

    Air pollution data around a monitored site are normally difficult to analyze due to highly inter-related meteorological and topographical factors on top of many complicated atmospheric chemical interactions occurred in local and regional wind fields. The challenge prompts this study to develop a comprehensive data-mining algorithm of cluster analysis followed by meteorological and interspecies correlations to mitigate the inherent data complexity and dissimilarity. This study investigated the background features of acidic and basic air pollutants around a high-tech industrial park in Taiwan. Monthly samplings were taken at 10 sites around the park in a year. The temporal distribution plots show a baseline with two characteristic groups of high and low peaks. Hierarchical cluster analysis confirms that high peaks were primarily associated with low speed south wind in summer for all the chemical species, except for F(-), Cl(-), NH(3) and HF. Crosschecking with the topographical map identifies several major external sources in south and southwest. Further meteorological correlation suggests that HCl is highly positively associated with humidity, while Cl(-) is highly negatively associated with temperature, both for most stations. Interestingly, HNO(3) is highly negatively associated with wind speed for most stations and the hotspot was found in summer and around the foothill of Da-Tu Mountain in the northwest, a stagnant pocket on the study site. However, F(-) is highly positively associated with wind speed at downwind stations to the prevailing north wind in winter, indicating an internal source from the north. The presence of NH(4)(+) stimulates the formation of NO(3)(-), SO(4)(-2) (R=0.7), and HNO(3), H(2)SO(4), NH(3) (R=0.3-0.4). As H(2)SO(4) could be elevated to a level as high as 40% of the regulated standard, species interactions may be a dominate mechanism responsible for the substantial increase in summer from external sources.

  18. Chemical proteomics approaches for identifying the cellular targets of natural products.

    PubMed

    Wright, M H; Sieber, S A

    2016-05-04

    Covering: 2010 up to 2016Deconvoluting the mode of action of natural products and drugs remains one of the biggest challenges in chemistry and biology today. Chemical proteomics is a growing area of chemical biology that seeks to design small molecule probes to understand protein function. In the context of natural products, chemical proteomics can be used to identify the protein binding partners or targets of small molecules in live cells. Here, we highlight recent examples of chemical probes based on natural products and their application for target identification. The review focuses on probes that can be covalently linked to their target proteins (either via intrinsic chemical reactivity or via the introduction of photocrosslinkers), and can be applied "in situ" - in living systems rather than cell lysates. We also focus here on strategies that employ a click reaction, the copper-catalysed azide-alkyne cycloaddition reaction (CuAAC), to allow minimal functionalisation of natural product scaffolds with an alkyne or azide tag. We also discuss 'competitive mode' approaches that screen for natural products that compete with a well-characterised chemical probe for binding to a particular set of protein targets. Fuelled by advances in mass spectrometry instrumentation and bioinformatics, many modern strategies are now embracing quantitative proteomics to help define the true interacting partners of probes, and we highlight the opportunities this rapidly evolving technology provides in chemical proteomics. Finally, some of the limitations and challenges of chemical proteomics approaches are discussed.

  19. Chemical proteomics approaches for identifying the cellular targets of natural products

    PubMed Central

    Sieber, S. A.

    2016-01-01

    Covering: 2010 up to 2016 Deconvoluting the mode of action of natural products and drugs remains one of the biggest challenges in chemistry and biology today. Chemical proteomics is a growing area of chemical biology that seeks to design small molecule probes to understand protein function. In the context of natural products, chemical proteomics can be used to identify the protein binding partners or targets of small molecules in live cells. Here, we highlight recent examples of chemical probes based on natural products and their application for target identification. The review focuses on probes that can be covalently linked to their target proteins (either via intrinsic chemical reactivity or via the introduction of photocrosslinkers), and can be applied “in situ” – in living systems rather than cell lysates. We also focus here on strategies that employ a click reaction, the copper-catalysed azide–alkyne cycloaddition reaction (CuAAC), to allow minimal functionalisation of natural product scaffolds with an alkyne or azide tag. We also discuss ‘competitive mode’ approaches that screen for natural products that compete with a well-characterised chemical probe for binding to a particular set of protein targets. Fuelled by advances in mass spectrometry instrumentation and bioinformatics, many modern strategies are now embracing quantitative proteomics to help define the true interacting partners of probes, and we highlight the opportunities this rapidly evolving technology provides in chemical proteomics. Finally, some of the limitations and challenges of chemical proteomics approaches are discussed. PMID:27098809

  20. Trace metal variability in coastal waters of San Jorge Bay, Antofagasta, Chile: An environmental evaluation and statistical approach to propose local background levels.

    PubMed

    Valdés, J; Román, D; Guiñez, M; Rivera, L; Ávila, J; Cortés, P; Castillo, A

    2015-11-15

    Between 2008 and 2011, twelve metals from 384 coastal waters samples from San Jorge Bay (Antofagasta, northern Chile) were collected and analyzed. The goal was to evaluate the quality of the bay's water bodies according to the current Chilean Quality Guideline and to establish background levels for these metals. The result suggests that the coastal waters of San Jorge Bay are of very good quality suitable for recreational activities involving human body contact. The natural background thresholds established for this bay were significantly lower than primary and secondary water quality guidelines. The distribution of Cu, Zn and Pb, along the bay's coastline provides evidence of the effects of industrial activity. Both situations suggest that the threshold indicated in the environmental guidelines of the Chilean legislation may be overestimated and do not represent pollution-free environments.

  1. When Should We Use Care Robots? The Nature-of-Activities Approach.

    PubMed

    Santoni de Sio, Filippo; van Wynsberghe, Aimee

    2016-12-01

    When should we use care robots? In this paper we endorse the shift from a simple normative approach to care robots ethics to a complex one: we think that one main task of a care robot ethics is that of analysing the different ways in which different care robots may affect the different values at stake in different care practices. We start filling a gap in the literature by showing how the philosophical analysis of the nature of healthcare activities can contribute to (care) robot ethics. We rely on the nature-of-activities approach recently proposed in the debate on human enhancement, and we apply it to the ethics of care robots. The nature-of-activities approach will help us to understand why certain practice-oriented activities in healthcare should arguably be left to humans, but certain (predominantly) goal-directed activities in healthcare can be fulfilled (sometimes even more ethically) with the assistance of a robot. In relation to the latter, we aim to show that even though all healthcare activities can be considered as practice-oriented, when we understand the activity in terms of different legitimate 'fine-grained' descriptions, the same activities or at least certain components of them can be seen as clearly goal-directed. Insofar as it allows us to ethically assess specific functionalities of specific robots to be deployed in well-defined circumstances, we hold the nature-of-activities approach to be particularly helpful also from a design perspective, i.e. to realize the Value Sensitive Design approach.

  2. New concepts, experimental approaches, and dereplication strategies for the discovery of novel phytoestrogens from natural sources.

    PubMed

    Michel, Thomas; Halabalaki, Maria; Skaltsounis, Alexios-Leandros

    2013-05-01

    Phytoestrogens constitute an attractive research topic due to their estrogenic profile and their biological involvement in woman's health. Therefore, numerous studies are currently performed in natural products chemistry area aiming at the discovery of novel phytoestrogens. The main classes of phytoestrogens are flavonoids (flavonols, flavanones), isoflavonoids (isoflavones, coumestans), lignans, stilbenoids as well as miscellaneous chemical groups abundant in several edible and/or medicinal plants, belonging mostly to the Leguminosae family. As for other bioactives, the detection of new structures and more potent plant-derived phytoestrogens typically follows the general approaches currently available in the natural product discovery process. Plant-based approaches selected from traditional medicine knowledge and bioguided concepts are routinely employed. However, these approaches are associated with serious disadvantages such as time-consuming, repeated, and labor intensive processes as well as lack of specificity and reproducibility. In recent years, the natural products chemistry became more technology-driven, and several different strategies have been developed. Structure-oriented procedures and miniaturized approaches employing advanced hyphenated analytical platforms have recently emerged. They facilitate significantly not only the discovery of novel phytoestrogens but also the dereplication procedure leading to the anticipation of major drawbacks in natural products discovery. In this review, apart from the traditional concepts followed in phytochemistry for the discovery of novel biologically active compounds, recent applications in the field of extraction, analysis, fractionation, and identification of phytoestrogens will be discussed. Moreover, specific methodologies combining identification of actives and biological evaluation in parallel, such as liquid chromatography-biochemical detection, frontal affinity chromatography-mass spectrometry and pulsed

  3. A minimalist fragment approach for the design of natural-product-like synthetic scaffolds.

    PubMed

    Genis, Dmitry; Kirpichenok, Mikhail; Kombarov, Roman

    2012-11-01

    Chemistry groups involved in drug discovery continue to devote their efforts to improving compound design with the aim of identifying new drug candidates. Many crucial factors must be considered, including: chemical stability, synthetic difficulty, chemical complexity and diversity, ADMET properties, cost, chemical novelty and intellectual property issues, and 'biological appropriateness'. With regard to the latter point, natural products offer an outstanding source of biologically active molecules that provide many useful features that enable us to design innovative, biologically biased, synthetic compounds. This article outlines the recent approaches in this area and suggests a simple metric to assess synthetic compounds for natural product likeness.

  4. Refugia Research Coalition: A regional-scale approach for connecting refugia science to natural and cultural resource management

    EPA Science Inventory

    Background / question / methods Warmer air and water temperatures, changing precipitation patterns, and altered fire regimes associated with climate change threaten many important natural and cultural resources. Climate change refugia are areas relatively buffered from contempora...

  5. Climate impacts on arctic freshwater ecosystems and fisheries: background, rationale and approach of the Arctic Climate Impact Assessment (ACIA).

    PubMed

    Wrona, Frederick J; Prowse, Terry D; Reist, James D; Hobbie, John E; Lévesque, Lucie M J; Vincent, Warwick F

    2006-11-01

    Changes in climate and ultraviolet radiation levels in the Arctic will have far-reaching impacts, affecting aquatic species at various trophic levels, the physical and chemical environment that makes up their habitat, and the processes that act on and within freshwater ecosystems. Interactions of climatic variables, such as temperature and precipitation, with freshwater ecosystems are highly complex and can propagate through the ecosystem in ways that are difficult to project. This is partly due to a poor understanding of arctic freshwater systems and their basic interrelationships with climate and other environmental variables, and partly due to a paucity of long-term freshwater monitoring sites and integrated hydro-ecological research programs in the Arctic. The papers in this special issue are an abstraction of the analyses performed by 25 international experts and their associated networks on Arctic freshwater hydrology and related aquatic ecosystems that was initially published by the Arctic Climate Impact Assessment (ACIA) in 2005 as "Chapter 8--Freshwater Ecosystems and Fisheries". The papers provide a broad overview of the general hydrological and ecological features of the various freshwater ecosystems in the Arctic, including descriptions of each ACIA region, followed by a review of historical changes in freshwater systems during the Holocene. This is followed by an assessment of the effects of climate change on broad-scale hydro-ecology; aquatic biota and ecosystem structure and function; and arctic fish and fisheries. Potential synergistic and cumulative effects are also discussed, as are the roles of ultraviolet radiation and contaminants. The nature and complexity of many of the effects are illustrated using case studies from around the circumpolar north, together with a discussion of important threshold responses (i.e., those that produce stepwise and/or nonlinear effects). The issue concludes with summary the key findings, a list of gaps in

  6. Managing ecological drought and flood within a nature-based approach. Reality or illusion?

    NASA Astrophysics Data System (ADS)

    Halbac-Cotoara-Zamfir, Rares; Finger, David; Stolte, Jannes

    2017-04-01

    Water hazards events, emphasized by an improperly implemented water management, may lead to ecological degradation of ecosystems. Traditional water management has generally sought to dampen the natural variability of water flows in different types of ecosystems to attain steady and dependable water supplies for domestic and industrial uses, irrigation, navigation, and hydropower, and to moderate extreme water conditions such as floods and droughts. Ecological drought can be defined as a prolonged and widespread deficit in available water supplies — including changes in natural and managed hydrology — that create multiple stresses across ecosystems, becomes a critical concern among researchers being a phenomenon much more complex than the other types of drought and requesting a specific approach. The impact of drought on ecosystem services lead to the necessity of identifying and implementing eco-reclamation measures which can generate better ecological answers to droughts. Ecological flood is the type of flood analyzed in full consideration with ecological issues, in the analyze process being approached 4 key aspects: connectivity of water system, landscapes of river and lakes, mobility of water bodies, and safety of flood control. As a consequence, both ecological drought and ecological flood represents high challenges for ecological sustainable water management in the process of identifying structural and non-structural measures for covering human demands without causing affected ecosystems to degrade or simplify. An ecological flood and drought control system will combine both the needs of the ecosystems as well as and flood and drought control measures. The components ecosystems' natural flow regime defined by magnitude, frequency, duration and peak timing (high or low flows) interact to maintain the ecosystem productivity. This productivity can be impaired by altered flow regimes generally due to structural measures designed to control flooding. However

  7. Selection of background electrolyte for CZE analysis by a chemometric approach. Part I. Separation of a mixture of acidic non-steroidal anti-inflammatory drugs.

    PubMed

    Furlanetto, Sandra; Lanteri, Silvia; Orlandini, Serena; Gotti, Roberto; Giannini, Iacopo; Pinzauti, Sergio

    2007-03-12

    This paper is the first part of the presentation of a chemometric approach for the rapid selection of a suitable background electrolyte (BGE) in CZE analysis of small drug molecules. The strategy is based on principal component analysis and experimental design. In this first section, the approach is applied to the analysis of a mixture of six arylpropionic anti-inflammatory drugs. Initially, 222 possible aqueous background electrolytes (objects) were characterized using as descriptors pH, conductivity, ionic strength and relative viscosity. In order to allow the dissociation of the acidic analytes, this original data set was reduced to 154 background electrolytes with pH values higher than or equal to 5. Principal component analysis made it possible to graphically represent the new set of objects, described by the four variables, in a two-dimensional space. Among these electrolytes, Kennard-Stone algorithm selected ten objects to be tested by CZE, covering homogeneously principal component space. CZE analyses were carried out with the selected electrolytes, and 0.1 M borax was identified as the most suitable one for the specified application. Finally, the characteristics of the analysis were finely tuned by means of a response surface study, which allowed the best conditions to be determined: borax concentration, 0.09 M; methanol, 6% (v/v); temperature, 24 degrees C, voltage, 20 kV. Applying these conditions, a baseline resolution among the six compounds was obtained in less than 10 min.

  8. Introducing N-glycans into natural products through a chemoenzymatic approach**

    PubMed Central

    Huang, Wei; Ochiai, Hirofumi; Zhang, Xinyu; Wang, Lai-Xi

    2008-01-01

    The present study describes an efficient chemoenzymatic method for introducing a core N-glycan of glycoprotein origin into various lipophilic natural products. It was found that the endo-β-N-acetylglucosaminidase from Arthrobactor protophormiae (Endo-A) had broad substrate specificity and can accommodate a wide range of glucose (Glc)- or N-acetylglucosamine (GlcNAc)-containing natural products as acceptors for transglycosylation, when an N-glycan oxazoline was used as a donor substrate. Using lithocholic acid as a model compound, we have shown that introduction of an N-glycan could be achieved by a two-step approach: chemical glycosylation to introduce a monosaccharide (Glc or GlcNAc) as a handle, and then Endo-A catalyzed transglycosylation to accomplish the site-specific N-glycan attachment. For those natural products that already carry terminal Glc or GlcNAc residues, direct enzymatic transglycosylation using sugar oxazoline as the donor substrate was achievable to introduce an N-glycan. It was also demonstrated that simultaneous double glycosylation could be fulfilled when the natural product contains two Glc residues. This chemoenzymatic method is concise, site-specific, and highly convergent. Because N-glycans of glycoprotein origin can serve as ligands for diverse lectins and cell-surface receptors, introduction of a defined N-glycan into biologically significant natural products may bestow novel properties onto these natural products for drug discovery and development. PMID:18805520

  9. Identifying natural substrates for chaperonins using a sequence-based approach

    PubMed Central

    Stan, George; Brooks, Bernard R.; Lorimer, George H.; Thirumalai, D.

    2005-01-01

    The Escherichia coli chaperonin machinery, GroEL, assists the folding of a number of proteins. We describe a sequence-based approach to identify the natural substrate proteins (SPs) for GroEL. Our method is based on the hypothesis that natural SPs are those that contain patterns of residues similar to those found in either GroES mobile loop and/or strongly binding peptide in complex with GroEL. The method is validated by comparing the predicted results with experimentally determined natural SPs for GroEL. We have searched for such patterns in five genomes. In the E. coli genome, we identify 1422 (about one-third) sequences that are putative natural SPs. In Saccharomyces cerevisiae, 2885 (32%) of sequences can be natural substrates for Hsp60, which is the analog of GroEL. The precise number of natural SPs is shown to be a function of the number of contacts an SP makes with the apical domain (NC) and the number of binding sites (NB) in the oligomer with which it interacts. For known SPs for GroEL, we find ~4 < NC < 5 and 2 ≤ NB ≤ 4. A limited analysis of the predicted binding sequences shows that they do not adopt any preferred secondary structure. Our method also predicts the putative binding regions in the identified SPs. The results of our study show that a variety of SPs, associated with diverse functions, can interact with GroEL. PMID:15576562

  10. On the nature of heat effects and shear modulus softening in metallic glasses: A generalized approach

    NASA Astrophysics Data System (ADS)

    Kobelev, N. P.; Khonik, V. A.; Makarov, A. S.; Afonin, G. V.; Mitrofanov, Yu. P.

    2014-01-01

    The paper presents a new approach to the nature of heat effects and shear modulus softening in metallic glasses. The approach is based on the assumption that the glass contains quenched-in "defects"—elastic dipoles. Using the nonlinear elastic representation of the internal energy of glass with quenched-in elastic dipoles, we derive a simple analytical law, which connects the heat flow and temperature derivative of the shear modulus. Specially performed experiments confirmed the validity of this law. The exothermal and endothermal heat processes in glass reveal through the relaxation of the shear modulus confirming it as a key parameter for the understanding the relaxation processes in glasses.

  11. Rapid, Long-term Monitoring of CO2 Concentration and δ13CO2 at CCUS Sites Allows Discrimination of Leakage Patterns from Natural Background Values

    NASA Astrophysics Data System (ADS)

    Galfond, B.; Riemer, D. D.; Swart, P. K.

    2014-12-01

    In order for Carbon Capture Utilization and Storage (CCUS) to gain wide acceptance as a method for mitigating atmospheric CO2 concentrations, schemes must be devised to ensure that potential leakage is detected. New regulations from the US Environmental Protection Agency require monitoring and accounting for Class VI injection wells, which will remain a barrier to wide scale CCUS deployment until effective and efficient monitoring techniques have been developed and proven. Monitoring near-surface CO2 at injection sites to ensure safety and operational success requires high temporal resolution CO2 concentration and carbon isotopic (δ13C) measurements. The only technologies currently capable of this rapid measurement of δ13C are optical techniques such as Cavity Ringdown Spectroscopy (CRDS). We have developed a comprehensive remote monitoring approach using CRDS and a custom manifold system to obtain accurate rapid measurements from a large sample area over an extended study period. Our modified Picarro G1101-i CRDS allows for automated rapid and continuous field measurement of δ13CO2 and concentrations of relevant gas species. At our field site, where preparations have been underway for Enhanced Oil Recovery (EOR) operations, we have been able to measure biogenic effects on a diurnal scale, as well as variation due to precipitation and seasonality. Taking these background trends into account, our statistical treatment of real data has been used to improve signal-to-noise ratios by an order of magnitude over published models. Our system has proven field readiness for the monitoring of sites with even modest CO2 fluxes.

  12. Criterion for the nature of the superconducting transition in strongly interacting field theories: A holographic approach

    SciTech Connect

    Kim, Ki-Seok; Kim, Youngman; Kim, Kyung Kiu; Ko, Yumi

    2011-11-01

    It is beyond the present paradigm based on perturbation theory to reveal the nature of phase transitions in strongly interacting theories. Recently, the holographic approach has provided us with an effective dual description, mapping strongly coupled conformal theories to classical gravity theories. Resorting to the holographic approach, we propose a general criterion for the nature of the superconducting transition based on effective interactions between vortices. We find ''tricritical'' points in terms of the chemical potential for U(1) charges and an effective Ginzburg-Landau parameter, where vortices do not interact to separate the second-order (repulsive) from the first-order (attractive) transitions. We interpret the first-order transition as the Coleman-Weinberg mechanism, arguing that it is relevant to superconducting instabilities around quantum criticality.

  13. A Modeling Approach for Burn Scar Assessment Using Natural Features and Elastic Property

    SciTech Connect

    Tsap, L V; Zhang, Y; Goldgof, D B; Sarkar, S

    2004-04-02

    A modeling approach is presented for quantitative burn scar assessment. Emphases are given to: (1) constructing a finite element model from natural image features with an adaptive mesh, and (2) quantifying the Young's modulus of scars using the finite element model and the regularization method. A set of natural point features is extracted from the images of burn patients. A Delaunay triangle mesh is then generated that adapts to the point features. A 3D finite element model is built on top of the mesh with the aid of range images providing the depth information. The Young's modulus of scars is quantified with a simplified regularization functional, assuming that the knowledge of scar's geometry is available. The consistency between the Relative Elasticity Index and the physician's rating based on the Vancouver Scale (a relative scale used to rate burn scars) indicates that the proposed modeling approach has high potentials for image-based quantitative burn scar assessment.

  14. Omics and Environmental Science Genomic Approaches With Natural Fish Populations From Polluted Environments

    PubMed Central

    Bozinovic, Goran; Oleksiak, Marjorie F.

    2010-01-01

    Transcriptomics and population genomics are two complementary genomic approaches that can be used to gain insight into pollutant effects in natural populations. Transcriptomics identify altered gene expression pathways while population genomics approaches more directly target the causative genomic polymorphisms. Neither approach is restricted to a pre-determined set of genes or loci. Instead, both approaches allow a broad overview of genomic processes. Transcriptomics and population genomic approaches have been used to explore genomic responses in populations of fish from polluted environments and have identified sets of candidate genes and loci that appear biologically important in response to pollution. Often differences in gene expression or loci between polluted and reference populations are not conserved among polluted populations suggesting a biological complexity that we do not yet fully understand. As genomic approaches become less expensive with the advent of new sequencing and genotyping technologies, they will be more widely used in complimentary studies. However, while these genomic approaches are immensely powerful for identifying candidate gene and loci, the challenge of determining biological mechanisms that link genotypes and phenotypes remains. PMID:21072843

  15. Characterization and Monitoring of Natural Attenuation of Chlorinated Solvents in Ground Water: A Systems Approach

    NASA Astrophysics Data System (ADS)

    Cutshall, N. H.; Gilmore, T.; Looney, B. B.; Vangelas, K. M.; Adams, K. M.; Sink, C. H.

    2006-05-01

    Like many US industries and businesses, the Department of Energy (DOE) is responsible for remediation and restoration of soils and ground water contaminated with chlorinated ethenes. Monitored Natural Attenuation (MNA) is an attractive remediation approach and is probably the universal end-stage technology for removing such contamination. Since 2003 we have carried out a multifaceted program at the Savannah River Site designed to advance the state of the art for MNA of chlorinated ethenes in soils and groundwater. Three lines of effort were originally planned: 1) Improving the fundamental science for MNA, 2) Promoting better characterization and monitoring (CM) techniques, and 3) Advancing the regulatory aspects of MNA management. A fourth line, developing enhanced attenuation methods based on sustainable natural processes, was added in order to deal with sites where the initial natural attenuation capacity cannot offset contaminant loading rates. These four lines have been pursued in an integrated and mutually supportive fashion. Many DOE site-cleanup program managers view CM as major expenses, especially for natural attenuation where measuring attenuation is complex and the most critical attenuation mechanisms cannot be determined directly. We have reviewed new and developing approaches to CM for potential application in support of natural attenuation of chlorinated hydrocarbons in ground water at DOE sites (Gilmore, Tyler, et al., 2006 WSRC-TR- 2005-00199). Although our project is focused on chlorinated ethenes, many of the concepts and strategies are also applicable to a wider range of contaminants including radionuclides and metals. The greatest savings in CM are likely to come from new management approaches. New approaches can be based, for example, on conceptual models of attenuation capacity, the ability of a formation to reduce risks caused by contaminants. Using the mass balance concept as a guide, the integrated mass flux of contaminant is compared to

  16. Learning from nature – novel synthetic biology approaches for biomaterial design

    PubMed Central

    Bryksin, Anton V.; Brown, Ashley C.; Baksh, Michael M.; Finn, M.G.; Barker, Thomas H.

    2014-01-01

    Many biomaterials constructed today are complex chemical structures that incorporate biologically active components derived from nature, but the field can still be said to be in its infancy. The need for materials that bring sophisticated properties of structure, dynamics, and function to medical and non-medical applications will only grow. Increasing appreciation of the functionality of biological systems has caused biomaterials researchers to consider nature for design inspiration, and many examples exist of the use of biomolecular motifs. Yet, evolution, nature's only engine for the creation of new designs, has been largely ignored by the biomaterials community. Molecular evolution is an emerging tool that enables one to apply nature's engineering principles to non-natural situations using variation and selection. The purpose of this review is to highlight the most recent advances in the use of molecular evolution in synthetic biology applications for biomaterial engineering, and to discuss some of the areas in which this approach may be successfully applied in the future. PMID:24463066

  17. Some novel approaches for radioprotection and the beneficial effect of natural products.

    PubMed

    Maurya, Dharmendra K; Devasagayam, Thomas P A; Nair, Cherupally Krishnan K

    2006-02-01

    Due to the increased use of ionizing radiation in various aspects of human life especially in areas pertaining to radiotherapy of cancer, food preservation, agriculture, industry and power generation, there is a need to develop an effective and non-toxic radioprotector. The currently available ones have many drawbacks including high cost, side effects and toxicity. Several novel approaches are on to locate a potent radioprotector. These include mimics of antioxidant enzymes, nitroxides, melatonin, growth factors, gene therapy, hyperthermia apart from natural products. The latter has several advantages since they are non-toxic with proven therapeutic benefits. These can be classified as natural compounds and plant extracts; polyherbal formulations; besides natural and semi-natural compounds of plant origin. A review of the above agents, their efficacy in radioprotection and possible mechanisms responsible has been carried out. As India and many Eastern countries have an enormous heritage of vast natural dietary and time tested medicinal resources it is worth exploring the possibility of developing efficient, economically viable and clinically acceptable radioprotectors for human application from these resources.

  18. Current approaches and challenges for the metabolite profiling of complex natural extracts.

    PubMed

    Wolfender, Jean-Luc; Marti, Guillaume; Thomas, Aurélien; Bertrand, Samuel

    2015-02-20

    Metabolite profiling is critical in many aspects of the life sciences, particularly natural product research. Obtaining precise information on the chemical composition of complex natural extracts (metabolomes) that are primarily obtained from plants or microorganisms is a challenging task that requires sophisticated, advanced analytical methods. In this respect, significant advances in hyphenated chromatographic techniques (LC-MS, GC-MS and LC-NMR in particular), as well as data mining and processing methods, have occurred over the last decade. Together, these tools, in combination with bioassay profiling methods, serve an important role in metabolomics for the purposes of both peak annotation and dereplication in natural product research. In this review, a survey of the techniques that are used for generic and comprehensive profiling of secondary metabolites in natural extracts is provided. The various approaches (chromatographic methods: LC-MS, GC-MS, and LC-NMR and direct spectroscopic methods: NMR and DIMS) are discussed with respect to their resolution and sensitivity for extract profiling. In addition the structural information that can be generated through these techniques or in combination, is compared in relation to the identification of metabolites in complex mixtures. Analytical strategies with applications to natural extracts and novel methods that have strong potential, regardless of how often they are used, are discussed with respect to their potential applications and future trends.

  19. "Whoever Does Not Write Is Written": The Role of "Nature" in Post-Post Approaches to Environmental Education Research

    ERIC Educational Resources Information Center

    Russell, Constance L.

    2005-01-01

    While McKenzie mentions in passing her concern about anthropocentrism and human oppression of the natural world, she is mostly silent about the role of "nature" in post-post approaches to environmental education research. If one takes feminist poststructuralist ideas about voice and representation seriously, surely the place of "nature" in…

  20. Ensuring that ecological science contributes to natural resource management using a Delphi-derived approach

    SciTech Connect

    Wolfe, Amy K; Dale, Virginia H; Arthur, Taryn A; Baskaran, Latha Malar

    2017-01-01

    This chapter approaches participatory modeling in environmental decision making from an atypical perspective. It broadly addresses the question of how to assure that science conducted to assist practitioners improves resource management. More specifically, it describes a case involving environmental science and natural resource management at Fort Benning, a U.S. Army installation in the southeastern United States where disparate environmental research projects were funded by a single federal agency to enhance the ability of Fort Benning resource managers to achieve their resource management goals. The role of our effort was to integrate the scientific studies in a manner that would be meaningful and useful for resource managers. Hence we assembled a team consisting of an anthropologist, ecologist, microbiologist, statistician, and geographic information systems specialist who developed a common framework that served as the basis for this integration. The team first used a Delphi expert elicitation, which evolved into an approach more akin to facilitated negotiation. This second approach arose organically, particularly when our team took advantage of an opportunity for face-to-face interaction. Although the shift in our approach was unplanned, it proved to be highly productive. We discuss the potential utility of our approach for other situations and suggest that it would be useful to initiate at the beginning of research where the aim is to produce scientific results that meet practitioners needs, specifically in the realm of environmental science and resource management.

  1. Towards an integrated approach to natural hazards risk assessment using GIS: with reference to bushfires.

    PubMed

    Chen, Keping; Blong, Russell; Jacobson, Carol

    2003-04-01

    This paper develops a GIS-based integrated approach to risk assessment in natural hazards, with reference to bushfires. The challenges for undertaking this approach have three components: data integration, risk assessment tasks, and risk decision-making. First, data integration in GIS is a fundamental step for subsequent risk assessment tasks and risk decision-making. A series of spatial data integration issues within GIS such as geographical scales and data models are addressed. Particularly, the integration of both physical environmental data and socioeconomic data is examined with an example linking remotely sensed data and areal census data in GIS. Second, specific risk assessment tasks, such as hazard behavior simulation and vulnerability assessment, should be undertaken in order to understand complex hazard risks and provide support for risk decision-making. For risk assessment tasks involving heterogeneous data sources, the selection of spatial analysis units is important. Third, risk decision-making concerns spatial preferences and/or patterns, and a multicriteria evaluation (MCE)-GIS typology for risk decision-making is presented that incorporates three perspectives: spatial data types, data models, and methods development. Both conventional MCE methods and artificial intelligence-based methods with GIS are identified to facilitate spatial risk decision-making in a rational and interpretable way. Finally, the paper concludes that the integrated approach can be used to assist risk management of natural hazards, in theory and in practice.

  2. Mapping and valuing ecosystem services as an approach for conservation and natural-resource management.

    PubMed

    Tallis, Heather; Polasky, Stephen

    2009-04-01

    Current approaches to conservation and natural-resource management often focus on single objectives, resulting in many unintended consequences. These outcomes often affect society through unaccounted-for ecosystem services. A major challenge in moving to a more ecosystem-based approach to management that would avoid such societal damages is the creation of practical tools that bring a scientifically sound, production function-based approach to natural-resource decision making. A new set of computer-based models is presented, the Integrated Valuation of Ecosystem Services and Tradeoffs tool (InVEST) that has been designed to inform such decisions. Several of the key features of these models are discussed, including the ability to visualize relationships among multiple ecosystem services and biodiversity, the ability to focus on ecosystem services rather than biophysical processes, the ability to project service levels and values in space, sensitivity to manager-designed scenarios, and flexibility to deal with data and knowledge limitations. Sample outputs of InVEST are shown for two case applications; the Willamette Basin in Oregon and the Amazon Basin. Future challenges relating to the incorporation of social data, the projection of social distributional effects, and the design of effective policy mechanisms are discussed.

  3. An Amphibious Being: How Maritime Surveying Reshaped Darwin's Approach to Natural History.

    PubMed

    Sponsel, Alistair

    2016-06-01

    This essay argues that Charles Darwin's distinctive approach to studying distribution and diversity was shaped by his face-to-face interactions with maritime surveyors during the voyage of H.M.S. Beagle (1831-1836). Introducing their hydrographic surveying methods into natural history enabled him to compare fossil and living marine organisms, to compare sedimentary rocks to present-day marine sediments, and to compare landscapes to submarine topology, thereby realizing Charles Lyell's fanciful ambition for a superior form of geology that might be practiced by an "amphibious being." Darwin's theories of continental uplift, coral reef formation, and the origin of species all depended on his amphibious natural history. This essay contributes to our understanding of theorizing in nineteenth-century natural history by illustrating that specific techniques of observing and collecting could themselves help to generate a particular theoretical orientation and, indeed, that such practical experiences were a more proximate source of Darwin's "Humboldtian" interest in distribution and diversity than Alexander von Humboldt's writings themselves. Darwin's debt to the hydrographers became obscured in two ways: through the "funneling" of credit produced by single-authorship publication in natural history and the "telescoping" of memory by which Darwin's new theories made him recall his former researches as though he had originally undertaken them for the very purpose of producing the later theory.

  4. Development of Antiatherosclerotic Drugs on the basis of Natural Products Using Cell Model Approach

    PubMed Central

    Orekhov, Alexander N.; Sobenin, Igor A.; Revin, Victor V.; Bobryshev, Yuri V.

    2015-01-01

    Atherosclerosis including its subclinical form is one of the key medical and social problems. At present, there is no therapy available for widespread use against subclinical atherosclerosis. The use of synthetic drugs for the prevention of arteriosclerosis in its early stages is not sufficient because of the limited indications for severe side effects and high cost of treatment. Obviously, effective antiatherosclerotic drugs based on natural products would be a preferred alternative. Simple cell-based models for testing different natural products have been developed and the ability of natural products to prevent intracellular lipid accumulation in primary cell culture was evaluated. This approach utilizing cell models allowed to test effects of such direct antiatherosclerotic therapy, analyzing the effects mimicking those which can occur “at the level” of arterial wall via the inhibition of intracellular lipid deposition. The data from the carried out clinical trials support a point of view that the identification of antiatherosclerotic activity of natural products might offer a great opportunity for the prevention and treatment of atherosclerotic disease, reducing cardiovascular morbidity and mortality. PMID:26347804

  5. Ultrasensitive Negative Feedback Control: A Natural Approach for the Design of Synthetic Controllers

    PubMed Central

    Montefusco, Francesco; Akman, Ozgur E.; Soyer, Orkun S.; Bates, Declan G.

    2016-01-01

    Many of the most important potential applications of Synthetic Biology will require the ability to design and implement high performance feedback control systems that can accurately regulate the dynamics of multiple molecular species within the cell. Here, we argue that the use of design strategies based on combining ultrasensitive response dynamics with negative feedback represents a natural approach to this problem that fully exploits the strongly nonlinear nature of cellular information processing. We propose that such feedback mechanisms can explain the adaptive responses observed in one of the most widely studied biomolecular feedback systems—the yeast osmoregulatory response network. Based on our analysis of such system, we identify strong links with a well-known branch of mathematical systems theory from the field of Control Engineering, known as Sliding Mode Control. These insights allow us to develop design guidelines that can inform the construction of feedback controllers for synthetic biological systems. PMID:27537373

  6. Bio-Emulation: biomimetically emulating nature utilizing a histoanatomic approach; visual synthesis.

    PubMed

    Bazos, Panaghiotis; Magne, Pascal

    2014-01-01

    A thorough understanding of the spatial distribution pertaining to the histo-anatomic coronal structures and dynamic light interaction of the natural dentition provides the dental team with the ultimate strategic advantage with regards to optical integration of the final restoration. The second part of this two-part article will attempt to provide insight on the illumination interactivity and the spatial arrangement of the coronal elements of natural teeth through the utilization of this knowledge in the clinical and technical restorative approach. The main goals for this article are to cognize histo-anatomic visualization by introducing: (1) Dynamic light interaction, (2) the 9 elements of visual synthesis, (3) dynamic infinite optical thickness, and (4) amplified visual perception effect of the hard dental tissues. Furthermore, a diversification of photographic illumination techniques will be illustrated in order to juxtapose optical associations between the enamel/dentinoenamel complex/dentin nexus.

  7. Biological and pharmacological approaches to the screening and evaluation of natural products.

    PubMed

    Lahlou, Mouhssen

    2003-01-01

    Many traditional herbal remedies contain active principles, the effects of which can be demonstrated pharmacologically; the biological activity of the whole plant extract is usually related to the constituents that have been identified. Thus, active extracts detected by screening methods are often subjected to more elaborate bioassays to determine their specific pharmacological activity. This paper aims to elucidate the biological, pharmacological and clinical approaches used in the screening of bioactive natural substances. In addition, a scientific process with the goal of finding substances with useful pharmacological activity in plant extracts is rigorously investigated.

  8. Task 23 - background report on subsurface environmental issues relating to natural gas sweetening and dehydration operations. Topical report, February 1, 1994--February 28, 1996

    SciTech Connect

    Sorensen, J.A.

    1998-12-31

    This report describes information pertaining to environmental issues, toxicity, environmental transport, and fate of alkanolamines and glycols associated with natural gas sweetening and dehydration operations. Waste management associated with the operations is also discussed.

  9. Human-Nature Interaction in the Eastern Pamirs of Tajikistan - Ecosystem services against the background of pasture use and energy consumption

    NASA Astrophysics Data System (ADS)

    Vanselow, K. A.; Samimi, C.; Kraudzun, T.; Kreutzmann, H.

    2012-04-01

    Mountains play an important role in the world's sustainable development. Despite the acquired knowledge about their importance the Global Environment Outlook 3 (UNEP 2002) states that most "mountain commons are ecologically under-managed and suffer from the classic 'commons syndrome': while all seek to benefit, stakeholders lack coordination, incentives and instruments for joint care." For the Eastern Pamirs, a dry (< 100 mm/a) and high (3,500-5,500 m asl) mountain plateau in the east of Tajikistan, grazing and fuel-wood are identified as key ecosystem services. Extensive pastoralism is a prime adapted land use strategy. Therefore, the Soviet administration allocated the production of meat on collective and state farms as the region's main task. Elaborate management plans, usually with four seasonal pasture camps, and additional imports of fuel and forage, led to a well-balanced utilization of all pastures. The dissolution of the USSR resulted in significant structural changes in the region. Most notably, the end of the subsidy system stopped the provisioning from outside. Without external inputs bridging long distances between the seasonal pastures poses a major problem to most smallholders. Furthermore, the limited supply and high cost of imported fossil fuels induced the increased use of dwarf shrubs as an energy resource. However, they are also important forage plants, particularly in winter. This study aims to provide a well-founded overview of the pasture and fuel-wood resources and the spatiotemporal variability of the actual pasture use with associated livestock numbers to make assertions on overuse in particular areas. Therefore, an interdisciplinary approach was used, combining geoecological and socio-economic methods. To assess the pasture potential information about land cover, phytomass availability, and forage quality were collected. Vegetation classes were modeled with a Random Forest (Breiman 2001), based on land cover information of 262 test plots

  10. Discovery and development of natural product-derived chemotherapeutic agents based on a medicinal chemistry approach.

    PubMed

    Lee, Kuo-Hsiung

    2010-03-26

    Medicinal plants have long been an excellent source of pharmaceutical agents. Accordingly, the long-term objectives of the author's research program are to discover and design new chemotherapeutic agents based on plant-derived compound leads by using a medicinal chemistry approach, which is a combination of chemistry and biology. Different examples of promising bioactive natural products and their synthetic analogues, including sesquiterpene lactones, quassinoids, naphthoquinones, phenylquinolones, dithiophenediones, neo-tanshinlactone, tylophorine, suksdorfin, DCK, and DCP, will be presented with respect to their discovery and preclinical development as potential clinical trial candidates. Research approaches include bioactivity- or mechanism of action-directed isolation and characterization of active compounds, rational drug design-based modification and analogue synthesis, and structure-activity relationship and mechanism of action studies. Current clinical trial agents discovered by the Natural Products Research Laboratories, University of North Carolina, include bevirimat (dimethyl succinyl betulinic acid), which is now in phase IIb trials for treating AIDS. Bevirimat is also the first in a new class of HIV drug candidates called "maturation inhibitors". In addition, an etoposide analogue, GL-331, progressed to anticancer phase II clinical trials, and the curcumin analogue JC-9 is in phase II clinical trials for treating acne and in development for trials against prostate cancer. The discovery and development of these clinical trial candidates will also be discussed.

  11. The normative background of empirical-ethical research: first steps towards a transparent and reasoned approach in the selection of an ethical theory.

    PubMed

    Salloch, Sabine; Wäscher, Sebastian; Vollmann, Jochen; Schildmann, Jan

    2015-04-04

    Empirical-ethical research constitutes a relatively new field which integrates socio-empirical research and normative analysis. As direct inferences from descriptive data to normative conclusions are problematic, an ethical framework is needed to determine the relevance of the empirical data for normative argument. While issues of normative-empirical collaboration and questions of empirical methodology have been widely discussed in the literature, the normative methodology of empirical-ethical research has seldom been addressed. Based on our own research experience, we discuss one aspect of this normative methodology, namely the selection of an ethical theory serving as a background for empirical-ethical research. Whereas criteria for a good ethical theory in philosophical ethics are usually related to inherent aspects, such as the theory's clarity or coherence, additional points have to be considered in the field of empirical-ethical research. Three of these additional criteria will be discussed in the article: (a) the adequacy of the ethical theory for the issue at stake, (b) the theory's suitability for the purposes and design of the empirical-ethical research project, and (c) the interrelation between the ethical theory selected and the theoretical backgrounds of the socio-empirical research. Using the example of our own study on the development of interventions which support clinical decision-making in oncology, we will show how the selection of an ethical theory as a normative background for empirical-ethical research can proceed. We will also discuss the limitations of the procedures chosen in our project. The article stresses that a systematic and reasoned approach towards theory selection in empirical-ethical research should be given priority rather than an accidental or implicit way of choosing the normative framework for one's own research. It furthermore shows that the overall design of an empirical-ethical study is a multi-faceted endeavor which has to

  12. Recent advances in natural product-based anti-biofilm approaches to control infections.

    PubMed

    Buommino, Elisabetta; Scognamiglio, Monica; Donnarumma, Giovanna; Fiorentino, Antonio; D'Abrosca, Brigida

    2014-01-01

    Bacterial biofilms are highly organized surface-associated communities of bacteria encased within an extracellular matrix produced by themselves, capable of growing in connection with different biological or inert surfaces such as artificial joints or catheters. Biofilms are commonly associated with many health problems, such as endocarditis, otitis media, periodontitis, prostatitis, and urinary tract infections. Several bacteria, such as Escherichia coli, Staphylococcus aureus, Streptococcus mutans, and Pseudomonas aeruginosa, or fungal pathogen as Candida albicans, can form biofilms in the body tissues, leading to different infections. The inherently defensive character of the biofilm is demonstrated by enhanced persistence of bacteria grown in the sessile mode respect to bacteria grown planktonically. This makes most biofilm- associated infections difficult to eradicate, thus contributing to disease chronicity. Since natural products provide a diverse array of chemical structures and possess a wide variety of biological properties, natural resources are worldwide exploited in the search of new pharmaceuticals. In this context bioactive secondary metabolites from natural sources, useful for the new antimicrobial and anti-biofilm drugs, are of interest. In this review, the role of small molecules from plants and marine organisms in inhibiting and/or dispersing bacterial biofilms is discussed, as well as the approaches that have been applied to the discovery of lead small molecules that mediate biofilm development. Molecules inhibiting the formation of biofilm may have therapeutic potential. Several candidates, as halogenated furanones, 2-amminoimidazole alkaloids and flavonoids have been already isolated and characterized from many plants and from marine organisms.

  13. New approaches for studying the chemical diversity of natural resources and the bioactivity of their constituents.

    PubMed

    Wolfender, Jean-Luc; Queiroz, Emerson Ferreira

    2012-01-01

    Natural products (NPs) have historically been an important source of lead molecules in drug discovery. However, the interest that the pharmaceutical industry has had in NPs has declined in part because of the lack of compatibility of traditional natural-product extract libraries with high-throughput screenings and the low hit rate. Furthermore, in contrast to the synthetic libraries, compounds from natural sources are likely to have complex structures which slow down the identification process and contribute to problems related to supply and manufacturing. In this paper, we summarise some of the strategies that are being developed in our research unit to address these issues. On one hand, differential screening strategies were established with the aim of identifying dynamically induced NPs from silent biosynthetic pathways in plants and fungi that had been exposed to different stress situations. On the other hand, high-resolution HPLC techniques were optimised for biological and chemical profiling of crude extracts. This led to an integrated platform for rapid and efficient identification of new drug-leads and biomarkers of interest that were based on miniaturised technological approaches and metabolomics.

  14. Rational biosynthetic approaches for the production of new-to-nature compounds in fungi.

    PubMed

    Boecker, Simon; Zobel, Sophia; Meyer, Vera; Süssmuth, Roderich D

    2016-04-01

    Filamentous fungi have the ability to produce a wide range of secondary metabolites some of which are potent toxins whereas others are exploited as food additives or drugs. Fungal natural products still play an important role in the discovery of new chemical entities for potential use as pharmaceuticals. However, in most cases they cannot be directly used as drugs due to toxic side effects or suboptimal pharmacokinetics. To improve drug-like properties, including bioactivity and stability or to produce better precursors for semi-synthetic routes, one needs to generate non-natural derivatives from known fungal secondary metabolites. In this minireview, we describe past and recent biosynthetic approaches for the diversification of fungal natural products, covering examples from precursor-directed biosynthesis, mutasynthesis, metabolic engineering and biocombinatorial synthesis. To illustrate the current state-of-the-art, challenges and pitfalls, we lay particular emphasis on the class of fungal cyclodepsipeptides which have been studied longtime for product diversification and which are of pharmaceutical relevance as drugs.

  15. Phylogeny-guided (meta)genome mining approach for the targeted discovery of new microbial natural products.

    PubMed

    Kang, Hahk-Soo

    2017-02-01

    Genomics-based methods are now commonplace in natural products research. A phylogeny-guided mining approach provides a means to quickly screen a large number of microbial genomes or metagenomes in search of new biosynthetic gene clusters of interest. In this approach, biosynthetic genes serve as molecular markers, and phylogenetic trees built with known and unknown marker gene sequences are used to quickly prioritize biosynthetic gene clusters for their metabolites characterization. An increase in the use of this approach has been observed for the last couple of years along with the emergence of low cost sequencing technologies. The aim of this review is to discuss the basic concept of a phylogeny-guided mining approach, and also to provide examples in which this approach was successfully applied to discover new natural products from microbial genomes and metagenomes. I believe that the phylogeny-guided mining approach will continue to play an important role in genomics-based natural products research.

  16. Two approaches for incorporating climate change into natural resource management planning at Wind Cave National Park

    USGS Publications Warehouse

    Symstad, Amy; Long, Andrew J.; Stamm, John; King, David A.; Bachelet, Dominque M.; Norton, Parker A.

    2014-01-01

    Wind Cave National Park (WICA) protects one of the world’s longest caves, has large amounts of high quality, native vegetation, and hosts a genetically important bison herd. The park’s relatively small size and unique purpose within its landscape requires hands-on management of these and other natural resources, all of which are interconnected. Anthropogenic climate change presents an added challenge to WICA natural resource management because it is characterized by large uncertainties, many of which are beyond the control of park and National Park Service (NPS) staff. When uncertainty is high and control of this uncertainty low, scenario planning is an appropriate tool for determining future actions. In 2009, members of the NPS obtained formal training in the use of scenario planning in order to evaluate it as a tool for incorporating climate change into NPS natural resource management planning. WICA served as one of two case studies used in this training exercise. Although participants in the training exercise agreed that the scenario planning process showed promise for its intended purpose, they were concerned that the process lacked the scientific rigor necessary to defend the management implications derived from it in the face of public scrutiny. This report addresses this concern and others by (1) providing a thorough description of the process of the 2009 scenario planning exercise, as well as its results and management implications for WICA; (2) presenting the results of a follow-up, scientific study that quantitatively simulated responses of WICA’s hydrological and ecological systems to specific climate projections; (3) placing these climate projections and the general climate scenarios used in the scenario planning exercise in the broader context of available climate projections; and (4) comparing the natural resource management implications derived from the two approaches. Wind Cave National Park (WICA) protects one of the world’s longest caves

  17. Nonlinear and higher-order approaches to the encoding of natural scenes.

    PubMed

    Zetzsche, Christoph; Nuding, Ulrich

    2005-01-01

    Linear operations can only partially exploit the statistical redundancies of natural scenes, and nonlinear operations are ubiquitous in visual cortex. However, neither the detailed function of the nonlinearities nor the higher-order image statistics are yet fully understood. We suggest that these complicated issues can not be tackled by one single approach, but require a range of methods, and the understanding of the crosslinks between the results. We consider three basic approaches: (i) State space descriptions can theoretically provide complete information about statistical properties and nonlinear operations, but their practical usage is confined to very low-dimensional settings. We discuss the use of representation-related state-space coordinates (multivariate wavelet statistics) and of basic nonlinear coordinate transformations of the state space (e.g., a polar transform). (ii) Indirect methods, like unsupervised learning in multi-layer networks, provide complete optimization results, but no direct information on the statistical properties, and no simple model structures. (iii) Approximation by lower-order terms of power-series expansions is a classical strategy that has not yet received broad attention. On the statistical side, this approximation amounts to cumulant functions and higher-order spectra (polyspectra), on the processing side to Volterra Wiener systems. In this context we suggest that an important concept for the understanding of natural scene statistics, of nonlinear neurons, and of biological pattern recognition can be found in AND-like combinations of frequency components. We investigate how the different approaches can be related to each other, how they can contribute to the understanding of cortical nonlinearities such as complex cells, cortical gain control, end-stopping and other extraclassical receptive field properties, and how we can obtain a nonlinear perspective on overcomplete representations and invariant coding in visual cortex.

  18. Using a meta-ethnographic approach to explore the nature of facilitation and teaching approaches employed in interprofessional education.

    PubMed

    Reeves, Scott; Pelone, Ferruccio; Hendry, Julie; Lock, Nicholas; Marshall, Jayne; Pillay, Leontia; Wood, Ruth

    2016-12-01

    Interprofessional facilitators and teachers are regarded as central to the effective delivery of interprofessional education (IPE). As the IPE literature continues to expand, most studies have focused on reporting learner outcomes, with little attention paid to IPE facilitation. However, a number of studies have recently emerged reporting on this phenomenon. To present a synthesis of qualitative evidence on the facilitation of IPE, using a meta-ethnographic approach. Electronic databases and journals were searched for the past 10 years. Of the 2164 abstracts initially found, 94 full papers were reviewed and subsequently 12 papers were included. Teams of two reviewers independently completed each step in the review process. The quality of these papers was assessed using a modified critical appraisal checklist. Seven key concepts embedded in the included studies were synthesized into three main factors which provided an insight into the nature of IPE facilitation. Specifically, the synthesis found that IPE facilitation is influenced by "contextual characteristics"; "facilitator experiences"; and the "use of different facilitation strategies". IPE facilitation is a complex activity affected by contextual, experiential and pedagogical factors. Further research is needed to explore the effects of these factors on the delivery of IPE.

  19. An Approach to Teaching General Chemistry II that Highlights the Interdisciplinary Nature of Science*,†

    PubMed Central

    Sumter, Takita Felder; Owens, Patrick M.

    2012-01-01

    The need for a revised curriculum within the life sciences has been well-established. One strategy to improve student preparation in the life sciences is to redesign introductory courses like biology, chemistry, and physics so that they better reflect their disciplinary interdependence. We describe a medically relevant, context-based approach to teaching second semester general chemistry that demonstrates the interdisciplinary nature of biology and chemistry. Our innovative method provides a model in which disciplinary barriers are diminished early in the undergraduate science curriculum. The course is divided into three principle educational modules: 1) Fundamentals of General Chemistry, 2) Medical Approaches to Inflammation, and 3) Neuroscience as a connector of chemistry, biology, and psychology. We accurately anticipated that this modified approach to teaching general chemistry would enhance student interest in chemistry and bridge the perceived gaps between biology and chemistry. The course serves as a template for context-based, interdisciplinary teaching that lays the foundation needed to train 21st century scientists. PMID:21445902

  20. An approach to teaching general chemistry II that highlights the interdisciplinary nature of science.

    PubMed

    Sumter, Takita Felder; Owens, Patrick M

    2011-01-01

    The need for a revised curriculum within the life sciences has been well-established. One strategy to improve student preparation in the life sciences is to redesign introductory courses like biology, chemistry, and physics so that they better reflect their disciplinary interdependence. We describe a medically relevant, context-based approach to teaching second semester general chemistry that demonstrates the interdisciplinary nature of biology and chemistry. Our innovative method provides a model in which disciplinary barriers are diminished early in the undergraduate science curriculum. The course is divided into three principle educational modules: 1) Fundamentals of General Chemistry, 2) Medical Approaches to Inflammation, and 3) Neuroscience as a connector of chemistry, biology, and psychology. We accurately anticipated that this modified approach to teaching general chemistry would enhance student interest in chemistry and bridge the perceived gaps between biology and chemistry. The course serves as a template for context-based, interdisciplinary teaching that lays the foundation needed to train 21st century scientists. Copyright © 2010 Wiley Periodicals, Inc.

  1. How to Use Historical Approach to Teach Nature of Science in Chemistry Education?

    NASA Astrophysics Data System (ADS)

    Tolvanen, Simo; Jansson, Jan; Vesterinen, Veli-Matti; Aksela, Maija

    2014-08-01

    Successful implementation of historical approach to teach nature of science (NOS) requires suitable curriculum material. Several research and development projects have produced lesson plans for science teachers. 25 lesson plans from four different projects involved in creating curriculum material utilizing historical approach in chemistry education were analyzed to describe NOS content included as well as the historical experiments and narratives used. Based on the results of descriptive content analysis of existing curriculum materials, several suggestions on the successful design of lesson plans utilizing historical approach are made. To increase the coherence and clarity of learning objectives and instruction, each lesson plan should focus on the limited amount of specific NOS issues instead of several overtly general NOS aspects. To support explicit classroom discussion on the selected NOS issues, historical narratives used in the lesson plans should illustrate these issues. The lesson plans should also include instructions on how to facilitate classroom discussion, such as questions for students to discuss and reflect. Recommendations are also made concerning the appropriate use of historical experiments and narrative elements such as viewpoint characters and conflicts.

  2. A Bayesian approach to modelling the natural history of a chronic condition from observations with intervention.

    PubMed

    Craig, B A; Fryback, D G; Klein, R; Klein, B E

    1999-06-15

    To assess the costs and benefits of screening and treatment strategies, it is important to know what would have happened had there been no intervention. In today's ethical climate, however, it is almost impossible to observe this directly and therefore must be inferred from observations with intervention. In this paper, we illustrate a Bayesian approach to this situation when the observations are at separated and unequally spaced time points and the time of intervention is interval censored. We develop a discrete-time Markov model which combines a non-homogeneous Markov chain, used to model the natural progression, with mechanisms that describe the possibility of both treatment intervention and death. We apply this approach to a subpopulation of the Wisconsin Epidemiologic Study of Diabetic Retinopathy, a population-based cohort study to investigate prevalence, incidence, and progression of diabetic retinopathy. In addition, posterior predictive distributions are discussed as a prognostic tool to assist researchers in evaluating costs and benefits of treatment protocols. While we focus this approach on diabetic retinopathy cohort data, we believe this methodology can have wide application.

  3. Multi-period natural gas market modeling Applications, stochastic extensions and solution approaches

    NASA Astrophysics Data System (ADS)

    Egging, Rudolf Gerardus

    This dissertation develops deterministic and stochastic multi-period mixed complementarity problems (MCP) for the global natural gas market, as well as solution approaches for large-scale stochastic MCP. The deterministic model is unique in the combination of the level of detail of the actors in the natural gas markets and the transport options, the detailed regional and global coverage, the multi-period approach with endogenous capacity expansions for transportation and storage infrastructure, the seasonal variation in demand and the representation of market power according to Nash-Cournot theory. The model is applied to several scenarios for the natural gas market that cover the formation of a cartel by the members of the Gas Exporting Countries Forum, a low availability of unconventional gas in the United States, and cost reductions in long-distance gas transportation. 1 The results provide insights in how different regions are affected by various developments, in terms of production, consumption, traded volumes, prices and profits of market participants. The stochastic MCP is developed and applied to a global natural gas market problem with four scenarios for a time horizon until 2050 with nineteen regions and containing 78,768 variables. The scenarios vary in the possibility of a gas market cartel formation and varying depletion rates of gas reserves in the major gas importing regions. Outcomes for hedging decisions of market participants show some significant shifts in the timing and location of infrastructure investments, thereby affecting local market situations. A first application of Benders decomposition (BD) is presented to solve a large-scale stochastic MCP for the global gas market with many hundreds of first-stage capacity expansion variables and market players exerting various levels of market power. The largest problem solved successfully using BD contained 47,373 variables of which 763 first-stage variables, however using BD did not result in

  4. A Test of the Optimality Approach to Modelling Canopy gas Exchange by Natural Vegetation

    NASA Astrophysics Data System (ADS)

    Schymanski, S. J.; Sivapalan, M.; Roderick, M. L.; Beringer, J.; Hutley, L. B.

    2005-12-01

    Natural vegetation has co-evolved with its environment over a long period of time and natural selection has led to a species composition that is most suited for the given conditions. Part of this adaptation is the vegetation's water use strategy, which determines the amount and timing of water extraction from the soil. Knowing that water extraction by vegetation often accounts for over 90% of the annual water balance in some places, we need to understand its controls if we want to properly model the hydrologic cycle. Water extraction by roots is driven by transpiration from the canopy, which in turn is an inevitable consequence of CO2 uptake for photosynthesis. Photosynthesis provides plants with their main building material, carbohydrates, and with the energy necessary to thrive and prosper in their environment. Therefore we expect that natural vegetation would have evolved an optimal water use strategy to maximise its `net carbon profit' (the difference between carbon acquired by photosynthesis and carbon spent on maintenance of the organs involved in its uptake). Based on this hypothesis and on an ecophysiological gas exchange and photosynthesis model (Cowan and Farquhar 1977; von Caemmerer 2000), we model the optimal vegetation for a site in Howard Springs (N.T., Australia) and compare the modelled fluxes with measurements by Beringer, Hutley et al. (2003). The comparison gives insights into theoretical and real controls on transpiration and photosynthesis and tests the optimality approach to modelling gas exchange of natural vegetation with unknown properties. The main advantage of the optimality approach is that no assumptions about the particular vegetation on a site are needed, which makes it very powerful for predicting vegetation response to long-term climate- or land use change. Literature: Beringer, J., L. B. Hutley, et al. (2003). "Fire impacts on surface heat, moisture and carbon fluxes from a tropical savanna in northern Australia." International

  5. Risk Governance of Multiple Natural Hazards: Centralized versus Decentralized Approach in Europe

    NASA Astrophysics Data System (ADS)

    Komendantova, Nadejda; Scolobig, Anna; Vinchon, Charlotte

    2014-05-01

    The multi-risk approach is a relatively new field and its definition includes the need to consider multiple hazards and vulnerabilities in their interdependency (Selva, 2013) and the current multi-hazards disasters, such as the 2011 Tohoku earthquake, tsunami and nuclear catastrophe, showed the need for a multi-risk approach in hazard mitigation and management. Our knowledge about multi-risk assessment, including studies from different scientific disciplines and developed assessment tools, is constantly growing (White et al., 2001). However, the link between scientific knowledge, its implementation and the results in terms of improved governance and decision-making have gained significantly less attention (IRGC, 2005; Kappes et al., 2012), even though the interest to risk governance, in general, has increased significantly during the last years (Verweiy and Thompson, 2006). Therefore, the key research question is how risk assessment is implemented and what is the potential for the implementation of a multi-risk approach in different governance systems across Europe. More precisely, how do the characteristics of risk governance, such as the degree of centralization versus decentralization, influence the implementation of a multi-risk approach. The methodology of this research includes comparative case study analysis of top-down and bottom-up interactions in governance in the city of Naples, (Italy), where the institutional landscape is marked by significant autonomy of Italian regions in decision-making processes for assessing the majority of natural risks, excluding volcanic, and in Guadeloupe, French West Indies, an overseas department of France, where the decision-making process is marked by greater centralization in decision making associated with a well established state governance within regions, delegated to the prefect and decentralised services of central ministries. The research design included documentary analysis and extensive empirical work involving

  6. Historical background.

    PubMed Central

    Epstein, M A

    2001-01-01

    The persisting ancient view of cancer as a contagious disease ended with 19th century scientific investigations which seemed to show it was not. The resulting dogma against an infectious cause for cancer produced great prejudice in the scientific community against the first report of an oncogenic virus by Rous early in the 20th century and, even in the 1950s, against Gross's finding of a murine leukaemia virus and a murine virus causing solid tumours. The Lucké frog renal carcinoma virus was the first cancer-associated herpesvirus. Intriguingly, an environmental factor, ambient temperature, determines virus genome expression in the poikilothermic frog cells. Although an alpha-herpesvirus, Marek's disease virus of chickens shares some aspects of biological behaviour with Epstein-Barr virus (EBV) of man. Very significantly, its lymphomas are the first naturally occurring malignancy to be controlled by an antiviral vaccine, with implications for human virus-associated cancers. The circumstances and climate of opinion in which successive gamma-herpesviruses were discovered are described. The identification of EBV involved two unconventionalities: its finding in cultured Burkitt's lymphoma cells when no human lymphoid cell had ever been maintained in vitro, and its recognition in the absence of biological activity by the then new technique of electron microscopy. These factors engendered hostility to its acceptance as a new human tumour-associated virus. The EBV-like agents of Old World apes and monkeys and the T-lymphotropic gamma-herpesviruses of New World monkeys were found at about the same time, not long after the discovery of EBV. For many years these were thought to be the only gamma-herpesviruses of non-human primates; however, very recently B-lymphotropic EBV-like agents have been identified in New World species as well. Mouse herpesvirus 68 came to light by chance during a search for arboviruses and has become important as a laboratory model because of its

  7. Ambient Background Particulate Compositiion Outdoor Natural Background: Interferents/Clutter

    DTIC Science & Technology

    2011-08-01

    bacterial spores , fragments and components, plant fragments and debris, and animal fragments and debris, all of which may be associated with inert...routinely other than for health effects. Allergy caused by pollen (>15 urn) and mold is monitored for health effects by National Allergy 9...occurrence. To achieve this, measurement of pollens, bacteria, and fungal spores and dust particulates were undertaken for weekly periods at four

  8. Identification of serum biomarkers in dogs naturally infected with Babesia canis canis using a proteomic approach

    PubMed Central

    2014-01-01

    Background Canine babesiosis is a tick-borne disease that is caused by the haemoprotozoan parasites of the genus Babesia. There are limited data on serum proteomics in dogs, and none of the effect of babesiosis on the serum proteome. The aim of this study was to identify the potential serum biomarkers of babesiosis using proteomic techniques in order to increase our understanding about disease pathogenesis. Results Serum samples were collected from 25 dogs of various breeds and sex with naturally occurring babesiosis caused by B. canis canis. Blood was collected on the day of admission (day 0), and subsequently on the 1st and 6th day of treatment. Two-dimensional electrophoresis (2DE) of pooled serum samples of dogs with naturally occurring babesiosis (day 0, day 1 and day 6) and healthy dogs were run in triplicate. 2DE image analysis showed 64 differentially expressed spots with p ≤ 0.05 and 49 spots with fold change ≥2. Six selected spots were excised manually and subjected to trypsin digest prior to identification by electrospray ionisation mass spectrometry on an Amazon ion trap tandem mass spectrometry (MS/MS). Mass spectrometry data was processed using Data Analysis software and the automated Matrix Science Mascot Daemon server. Protein identifications were assigned using the Mascot search engine to interrogate protein sequences in the NCBI Genbank database. A number of differentially expressed serum proteins involved in inflammation mediated acute phase response, complement and coagulation cascades, apolipoproteins and vitamin D metabolism pathway were identified in dogs with babesiosis. Conclusions Our findings confirmed two dominant pathogenic mechanisms of babesiosis, haemolysis and acute phase response. These results may provide possible serum biomarker candidates for clinical monitoring of babesiosis and this study could serve as the basis for further proteomic investigations in canine babesiosis. PMID:24885808

  9. CASMI 2016: A manual approach for dereplication of natural products using tandem mass spectrometry.

    PubMed

    Nikolić, Dejan

    2017-09-01

    The Critical Assessment of Small Molecule Identification (CASMI) contest is an initiative designed as an unbiased test of manual and automated strategies for the identification of small molecules from raw mass spectrometric data. In this contest, the participants are provided a set of high resolution MS and MS/MS data and asked to identify the unknown structure. CASMI 2016 is the fourth round of this contest in which the author participated in Category 1: Best Identification of Natural Products using a manual approach. The provided high resolution mass spectrometric data were interpreted manually using a combination of fragment and neutral loss analysis, literature consultation, manual database searches, deductive logic and experience. Out of 18 challenges, the author submitted correct structures as lead candidates for 14 challenges and 2(nd) ranked candidate for four challenges and was declared the winner of this category Pitfalls and challenges encountered during data interpretation are discussed.

  10. A cultural neuroscience approach to the biosocial nature of the human brain.

    PubMed

    Han, Shihui; Northoff, Georg; Vogeley, Kai; Wexler, Bruce E; Kitayama, Shinobu; Varnum, Michael E W

    2013-01-01

    Cultural neuroscience (CN) is an interdisciplinary field that investigates the relationship between culture (e.g., value and belief systems and practices shared by groups) and human brain functions. In this review we describe the origin, aims, and methods of CN as well as its conceptual framework and major findings. We also clarify several misunderstandings of CN research. Finally, we discuss the implications of CN findings for understanding human brain function in sociocultural contexts and novel questions that future CN research should address. By doing so, we hope to provide a clear picture of the CN approach to the human brain and culture and to elucidate the intrinsically biosocial nature of the functional organization of the human brain.

  11. Design of multifunctional compounds for cardiovascular disease: from natural scaffolds to "classical" multitarget approach.

    PubMed

    Bisi, A; Gobbi, S; Belluti, F; Rampa, A

    2013-01-01

    Cardiovascular disease represents the main cause of death worldwide. Novel therapies to reduce elevated blood pressure and treat resistant hypertension, to consequently reduce the associated cardiovascular risk factors, are still required. Among the different strategies commonly used in medicinal chemistry to develop new molecules, the synthesis of multitarget/hybrid compounds combining two or more pharmacophore groups targeting simultaneously selected factors involved in cardiovascular diseases, has gained increasing interest. This review will focus on the most recent literature on multifunctional cardiovascular drugs, paying particular attention on hybrid compounds bearing natural scaffolds, considering that compounds derived from medicinal extracts are generally appealing for the medicinal chemist as they often bear the so-called "privileged structures". Moreover, taking into account many excellent reviews dealing with multitarget cardiovascular drugs published in the last few years, mainly devoted to RAAS inhibition and/or NO donors hybrid drugs, herein the most significant results obtained and the benefits and limitations of these approaches will be highlighted.

  12. Improvements in chronic diseases with a comprehensive natural medicine approach: a review and case series.

    PubMed

    Nader, T; Rothenberg, S; Averbach, R; Charles, B; Fields, J Z; Schneider, R H

    2000-01-01

    Approximately 40% of the US population report using complementary and alternative medicine, including Maharishi Vedic Medicine (MVM), a traditional, comprehensive system of natural medicine, for relief from chronic and other disorders. Although many reports suggest health benefits from individual MVM techniques, reports on integrated holistic approaches are rare. This case series, designed to investigate the effectiveness of an integrated, multimodality MVM program in an ideal clinical setting, describes the outcomes in four patients: one with sarcoidosis; one with Parkinson's disease; a third with renal hypertension; and a fourth with diabetes/essential hypertension/anxiety disorder. Standard symptom reports and objective markers of disease were evaluated before, during, and after the treatment period. Results suggested substantial improvements as indicated by reductions in major signs, symptoms, and use of conventional medications in the four patients during the 3-week in-residence treatment phase and continuing through the home follow-up program.

  13. Evolutionary genetics in wild primates: combining genetic approaches with field studies of natural populations.

    PubMed

    Tung, Jenny; Alberts, Susan C; Wray, Gregory A

    2010-08-01

    Ecological and evolutionary studies of wild primates hold important keys to understanding both the shared characteristics of primate biology and the genetic and phenotypic differences that make specific lineages, including our own, unique. Although complementary genetic research on nonhuman primates has long been of interest, recent technological and methodological advances now enable functional and population genetic studies in an unprecedented manner. In the past several years, novel genetic data sets have revealed new information about the demographic history of primate populations and the genetics of adaptively important traits. In combination with the rich history of behavioral, ecological, and physiological work on natural primate populations, genetic approaches promise to provide a compelling picture of primate evolution in the past and in the present day. Copyright 2010 Elsevier Ltd. All rights reserved.

  14. Improvements in Chronic Diseases With a Comprehensive Natural Medicine Approach: A Review and Case Series

    PubMed Central

    Nader, Tony; Rothenberg, Stuart; Averbach, Richard; Charles, Barry; Fields, Jeremy Z.; Schneider, Robert H.

    2008-01-01

    Approximately 40% of the US population report using complementary and alternative medicine, including Maharishi Vedic Medicine (MVM), a traditional, comprehensive system of natural medicine, for relief from chronic and other disorders. Although many reports suggest health benefits from individual MVM techniques, reports on integrated holistic approaches are rare. This case series, designed to investigate the effectiveness of an integrated, multi-modality MVM program in an ideal clinical setting, describes the outcomes in four patients: one with sarcoidosis; one with Parkinson’s disease; a third with renal hypertension; and a fourth with diabetes/essential hypertension/anxiety disorder. Standard symptom reports and objective markers of disease were evaluated before, during, and after the treatment period. Results suggested substantial improvements as indicated by reductions in major signs, symptoms, and use of conventional medications in the four patients during the 3-week in-residence treatment phase and continuing through the home follow-up program. PMID:10971882

  15. Multiphoton ionization and circular dichroism: new experimental approach and application to natural products.

    PubMed

    Logé, Christoph; Boesl, Ulrich

    2011-07-11

    Enantio-sensitive laser mass spectrometry is the combination of multiphoton ionization by circularly polarized laser light with mass spectrometric detection of ions. The method has been developed as a tool for the fast investigation of chiral molecules in sample mixtures without any preceding separation and offers many new experimental possibilities. The main difficulties of the detection of circular dichroism in this way arise from systematic and statistical deviations. Herein, we report the newest approach to overcome these problems using a so-called twin-peak ion source, back-reflection of the laser light, and reference substances. By these means, the detection limit for circular dichroism can be lowered from the percent to the per-mill range. The capabilities of the new setup are demonstrated by the investigation of several natural products.

  16. Investigating Natural Variation in Drosophila Courtship Song by the Evolve and Resequence Approach

    PubMed Central

    Turner, Thomas L.; Miller, Paige M.

    2012-01-01

    A primary goal of population genetics is to determine the genetic basis of natural trait variation. We could significantly advance this goal by developing comprehensive genome-wide approaches to link genotype and phenotype in model organisms. Here we combine artificial selection with population-based resequencing to investigate the genetic basis of variation in the interpulse interval (IPI) of Drosophila melanogaster courtship song. We performed divergent selection on replicate populations for only 14 generations, but had considerable power to differentiate alleles that evolved due to selection from those that evolved stochastically. We identified a large number of variants that changed frequency in response to selection for this simple behavior, and they are highly underrepresented on the X chromosome. Though our power was adequate using this experimental technique, the ability to differentiate causal variants from those affected by linked selection requires further development. PMID:22466043

  17. Evolutionary genetics in wild primates: combining genetic approaches with field studies of natural populations

    PubMed Central

    Tung, Jenny; Alberts, Susan C; Wray, Gregory A

    2010-01-01

    Ecological and evolutionary studies of wild primates hold important keys to understanding both the shared characteristics of primate biology and the genetic and phenotypic differences that make specific lineages, including our own, unique. Although complementary genetic research on nonhuman primates has long been of interest, recent technological and methodological advances now enable functional and population genetic studies in an unprecedented manner. In the past several years, novel genetic data sets have revealed new information about the demographic history of primate populations and the genetics of adaptively important traits. In combination with the rich history of behavioral, ecological, and physiological work on natural primate populations, genetic approaches promise to provide a compelling picture of primate evolution in the past and in the present day. PMID:20580115

  18. Kinetics of natural organic matter (NOM) removal during drinking water biofiltration using different NOM characterization approaches.

    PubMed

    Chen, Fei; Peldszus, Sigrid; Elhadidy, Ahmed M; Legge, Raymond L; Van Dyke, Michele I; Huck, Peter M

    2016-11-01

    To better understand biofiltration, concentration profiles of various natural organic matter (NOM) components throughout a pilot-scale drinking water biofilter were investigated using liquid chromatography - organic carbon detection (LC-OCD) and fluorescence excitation and emission matrices (FEEM). Over a 2 month period, water samples were collected from six ports at different biofilter media depths. Results showed substantial removal of biopolymers (i.e. high molecular weight (MW) NOM components as characterized by LC-OCD) and FEEM protein-like materials, but low removal of humic substances, building blocks and low MW neutrals and low MW acids. For the first time, relative biodegradability of different NOM components characterized by LC-OCD and FEEM approaches were investigated across the entire MW range and for different fluorophore compositions, in addition to establishing the biodegradation kinetics. The removal kinetics for FEEM protein-like materials were different than for the LC-OCD-based biopolymers, illustrating the complementary nature of the LC-OCD and FEEM approaches. LC-OCD biopolymers (both organic carbon and organic nitrogen) and FEEM protein-like materials were shown to follow either first or second order biodegradation kinetics. Due to the low percent removal and small number of data points, the performance of three kinetic models was not distinguishable for humic substances. Pre-filtration of samples for FEEM analyses affected the removal behaviours and/or kinetics especially of protein-like materials which was attributed to the removal of the colloidal/particulate materials. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Overview of the Enhanced Natural Gestures Instructional Approach and Illustration of Its Use with Three Students with Angelman Syndrome

    ERIC Educational Resources Information Center

    Calculator, Stephen; Diaz-Caneja Sela, Patricia

    2015-01-01

    Background: This investigation details procedures used to teach enhanced natural gestures (ENGs) and illustrates its use with three students with Angelman syndrome (AS). Materials and Methods: Themes were extracted, using a process of content analysis, to organize individuals' feedback pertaining to previous versions of the instructional…

  20. Overview of the Enhanced Natural Gestures Instructional Approach and Illustration of Its Use with Three Students with Angelman Syndrome

    ERIC Educational Resources Information Center

    Calculator, Stephen; Diaz-Caneja Sela, Patricia

    2015-01-01

    Background: This investigation details procedures used to teach enhanced natural gestures (ENGs) and illustrates its use with three students with Angelman syndrome (AS). Materials and Methods: Themes were extracted, using a process of content analysis, to organize individuals' feedback pertaining to previous versions of the instructional…

  1. Current advances in the development of natural meniscus scaffolds: innovative approaches to decellularization and recellularization.

    PubMed

    Chen, Yunbin; Chen, Jiaxin; Zhang, Zeng; Lou, Kangliang; Zhang, Qi; Wang, Shengyu; Ni, Jinhu; Liu, Wenyue; Fan, Shunwu; Lin, Xianfeng

    2017-03-31

    The increasing rate of injuries to the meniscus indicates the urgent need to develop effective repair strategies. Irreparably damaged menisci can be replaced and meniscus allografts represent the treatment of choice; however, they have several limitations, including availability and compatibility. Another approach is the use of artificial implants but their chondroprotective activities are still not proved clinically. In this situation, tissue engineering offers alternative natural decellularized extracellular matrix (ECM) scaffolds, which have shown biomechanical properties comparable to those of native menisci and are characterized by low immunogenicity and promising regenerative potential. In this article, we present an overview of meniscus decellularization methods and discuss their relative merits. In addition, we comparatively evaluate cell types used to repopulate decellularized scaffolds and analyze the biocompatibility of the existing experimental models. At present, acellular ECM hydrogels, as well as slices and powders, have been explored, which seems to be promising for partial meniscus regeneration. However, their inferior biomechanical properties (compressive and tensile stiffness) compared to natural menisci should be improved. Although an optimal decellularized meniscus scaffold still needs to be developed and thoroughly validated for its regenerative potential in vivo, we believe that decellularized ECM scaffolds are the future biomaterials for successful structural and functional replacement of menisci.

  2. Turn on the super-elastic collision nature of coronal mass ejections through low approaching speed

    PubMed Central

    Shen, Fang; Wang, Yuming; Shen, Chenglong; Feng, Xueshang

    2016-01-01

    It has been proved from the observations and numerical simulations that the collision between solar coronal mass ejections (CMEs), the largest plasmoids in the heliosphere, could be super-elastic. This finding suggests that the CMEs’ magnetic energy and thermal energy could be converted into kinetic energy through a more efficient way. However CME collisions are not always super-elastic, which means that this distinct property of plasmoids is probably excited conditionally. As the first attempt, we carry out a series of three-dimensional numerical experiments, and establish a diagram showing the dependence of the collision nature on the CME speed and k-number, the ratio of the CME’s kinetic energy to the CME’s total energy. It is found that the super-elastic nature of CMEs appears at the relatively low approaching speed, and most of the previous case studies are in agreement with this diagram. Our study firmly advances the understanding of the super-elastic property of plasmoids, and does give us new clues to deeply understand why and how the magnetic energy and/or thermal energy of the colliding plasmoids can be converted into kinetic energy in such an efficient way. PMID:26791543

  3. Structure elucidation and DNA binding specificity of natural compounds from Cassia siamea leaves: A biophysical approach.

    PubMed

    Parveen, Mehtab; Ahmad, Faheem; Malla, Ali Mohammed; Khan, Mohd Sohrab; Rehman, Sayeed Ur; Tabish, Mohammad; Silva, Manuela Ramos; Silva, P S Pereira

    2016-06-01

    A novel isoflavone, 5,6,7-trimethoxy-3-(3',4',5'-trimethoxyphenyl)-4H-chromen-4-one (1) along with a known pyranocoumarin, Seselin (2) have been isolated from the ethanolic extract of the leaves of Cassia siamea (Family: Fabaceae). Compound 1 has been reported for the first time from any natural source and has not been synthesized so far. Their structures were elucidated on the basis of chemical and physical evidences viz. elemental analysis, UV, FT-IR, (1)H-NMR, (13)C-NMR and mass spectral analysis. Structure of compound (1) was further authenticated by single-crystal X-ray analysis and density functional theory (DFT) calculations. A multi-technique approach employing UV-Visible spectroscopy, fluorescence, KI quenching studies, competitive displacement assay, circular dichroism and viscosity studies have been utilized to probe the extent of interaction and possible binding modes of isolated compounds (1-2) with calf thymus DNA (CT-DNA). Both the compounds were found to interact with DNA via non-intercalative binding mode with moderate proficiencies. Groove binding was the major interaction mode in the case of compound 2 while compound 1 probably interacts with DNA through electrostatic interactions. These studies provide deeper insight in understanding of DNA-drug (natural products) interaction which could be helpful to improve their bioavailability for therapeutic purposes. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Turn on the super-elastic collision nature of coronal mass ejections through low approaching speed.

    PubMed

    Shen, Fang; Wang, Yuming; Shen, Chenglong; Feng, Xueshang

    2016-01-21

    It has been proved from the observations and numerical simulations that the collision between solar coronal mass ejections (CMEs), the largest plasmoids in the heliosphere, could be super-elastic. This finding suggests that the CMEs' magnetic energy and thermal energy could be converted into kinetic energy through a more efficient way. However CME collisions are not always super-elastic, which means that this distinct property of plasmoids is probably excited conditionally. As the first attempt, we carry out a series of three-dimensional numerical experiments, and establish a diagram showing the dependence of the collision nature on the CME speed and k-number, the ratio of the CME's kinetic energy to the CME's total energy. It is found that the super-elastic nature of CMEs appears at the relatively low approaching speed, and most of the previous case studies are in agreement with this diagram. Our study firmly advances the understanding of the super-elastic property of plasmoids, and does give us new clues to deeply understand why and how the magnetic energy and/or thermal energy of the colliding plasmoids can be converted into kinetic energy in such an efficient way.

  5. The Nature of Elementary Student Science Discourse in the Context of the Science Writing Heuristic Approach

    NASA Astrophysics Data System (ADS)

    Cavagnetto, Andy; Hand, Brian M.; Norton-Meier, Lori

    2010-03-01

    This case study aimed to determine the nature of student interactions in small groups in an elementary classroom utilizing the Science Writing Heuristic approach. Fifth grade students were audio-recorded over four units of study while working in small groups to generate knowledge claims after conducting student-directed investigations. Analysis consisted of (1) identifying amount of on/off task talk, (2) categorizing on-task talk as generative (talk associated with generating an argument) or representational (talk associated with representing an argument in a final written form), (3) characterizing the generative components of argument, and (4) determining the functions of language used. Results indicate that students were on task 98% of the time. Students engaged in generative talk an average of 25% of the time and representational talk an average of 71% of the time. Students engaged in components of Toulmin's model of argument, but challenging of each other's ideas was not commonplace. Talk was dominated by the informative function (representing one's ideas) of language as it was found 78.3% of the time and to a lesser extent (11.7%) the heuristic function (inquiring through questions). These functions appear to be intimately tied to the task of generating knowledge claims in small groups. The results suggest that both talking and writing are critical to using science discourse as an embedded strategy to learning science. Further, nature and structure of the task are important pedagogical considerations when moving students toward participation in science discourse.

  6. Natural Organic Matter Transport Modeling with a Continuous Time Random Walk Approach

    PubMed Central

    McInnis, Daniel P.; Bolster, Diogo; Maurice, Patricia A.

    2014-01-01

    Abstract In transport experiments through columns packed with naturally Fe/Al oxide-coated quartz sand, breakthrough curves (BTCs) of natural organic matter (NOM) displayed strong and persistent power law tailing that could not be described by the classical advection–dispersion equation. Tailing was not observed in BTCs for a nonreactive tracer (sulforhodamine B); therefore, the anomalous transport is attributed to diverse adsorptive behavior of the polydisperse NOM sample rather than to physical heterogeneity of the porous medium. NOM BTC tailing became more pronounced with decreases in pH and increases in ionic strength, conditions previously shown to be associated with enhanced preferential adsorption of intermediate to high molecular weight NOM components. Drawing from previous work on anomalous solute transport, we develop an approach to model NOM transport within the framework of a continuous time random walk (CTRW) and show that under all conditions examined, the CTRW model is able to capture tailing of NOM BTCs by accounting for differences in transport rates of NOM fractions through a distribution of effective retardation factors. These results demonstrate the importance of considering effects of adsorptive fractionation on NOM mobility, and illustrate the ability of the CTRW model to describe transport of a multicomponent solute. PMID:24596449

  7. A novel modelling approach for evaluating the preindustrial natural carrying capacity of human population in Iceland.

    PubMed

    Haraldsson, Hörour V; Olafsdóttir, Rannveig

    2006-12-15

    The pre-industrial natural carrying capacity is believed to have limited the human population in Iceland to a maximum of fifty to sixty thousand inhabitants. Since AD 1800 the Icelandic population has gradually grown up to nearly 300 thousand in 2005. In this paper a simple approach is used to evaluate the potential population size that the pre-industrial Icelandic environment could possibly sustain. A dynamic model was constructed that simulates the population size according to potential biological production available for livestock. Biological production was determined by the extent of the total potential vegetation cover based on the Degree-Day concept. Fluctuations in the mean annual temperature causes changes in the potential vegetation cover and as a consequence change the biological production sustaining livestock and ultimately human population. The simulation's results indicate that the potential population that the Icelandic environments could sustain during the pre-industrial period fluctuated between 40 and 80 thousand. The results further indicate that the severe land degradation experienced after the Viking settlement period in AD 900 had a marginal impact on the population size. The pre-historical population did however overshoot the natural sustainability on several occasions.

  8. Natural ecosystem mimicry in traditional dryland agroecosystems: Insights from an empirical and holistic approach.

    PubMed

    Blanco, Julien; Michon, Geneviève; Carrière, Stéphanie M

    2017-08-30

    While the aim of Ecological Intensification is to enable the design of more sustainable and productive agricultural systems, it is not suited to dryland agroecosystems that are driven by non-equilibrium dynamics and intrinsic variability. Instead, a model based on mobility and variability management has been proposed for these agroecosystems. However, this model remains under-applied in southern Morocco where there have been few studies on the functioning of traditional agroecosystems. This paper focuses on an agroecosystem in the Moroccan Saharan fringe zone that combines agriculture and pastoralism in an acacia parkland. A grounded theory approach was used over a three-year investigation period (i) to highlight how agro-pastoral activities interface with environmental variability, and (ii) to analyze the formal and informal institutions that support these activities. Results show that farmers interface with rainfall variability through (i) an opportunistic agricultural calendar, (ii) a variation of cultivated areas, and (iii) crop diversification. Herders combine macro-mobility (nomads move over long distances to track rainfall) and micro-mobility (nomadic and sedentary herds are driven on a daily basis around settlements) to optimize the exploitation of ecological heterogeneity. During droughts, they also resort to State-subsidized forage supplies. Both cultivation and pastoral activities tend to interface with ecological dynamics and to mimic nature, resulting in a human-modified parkland that could be considered as a 'green agroecosystem'. The sustainability of natural resource use relies on flexible property rights, backed up by a social and cultural norm-based regulation system, that allow crop-livestock integration and landscape collective management. Despite encouraging results, the agroecosystem appears to be threatened by current agricultural policies, rural exodus and the lack of social recognition of nomadism. Nevertheless, because ecosystem mimicry of

  9. Investigating the Relationship between Test-Taker Background Characteristics and Test Performance in a Heterogeneous English-as-a-Second-Language (ESL) Test Population: A Factor Analytic Approach. Research Report. ETS RR-15-25

    ERIC Educational Resources Information Center

    Manna, Venessa F.; Yoo, Hanwook

    2015-01-01

    This study examined the heterogeneity in the English-as-a-second-language (ESL) test population by modeling the relationship between test-taker background characteristics and test performance as measured by the "TOEFL iBT"® using a confirmatory factor analysis (CFA) with covariate approach. The background characteristics studied…

  10. The Effect of Explicit-Reflective and Historical Approach on Preservice Elementary Teachers' Views of Nature of Science

    ERIC Educational Resources Information Center

    Pekbay, Canay; Yilmaz, Serkan

    2015-01-01

    This study aims to explore the influence of nature of science (NOS) activities based on explicit-reflective and historical approach on preservice elementary teachers' views of NOS aspects. Mixed-method approach including both qualitative and quantitative methods was used. The sample consisted of 83 preservice elementary teachers of a public…

  11. The Effect of Explicit-Reflective and Historical Approach on Preservice Elementary Teachers' Views of Nature of Science

    ERIC Educational Resources Information Center

    Pekbay, Canay; Yilmaz, Serkan

    2015-01-01

    This study aims to explore the influence of nature of science (NOS) activities based on explicit-reflective and historical approach on preservice elementary teachers' views of NOS aspects. Mixed-method approach including both qualitative and quantitative methods was used. The sample consisted of 83 preservice elementary teachers of a public…

  12. Resolving the chemical nature of nanodesigned silica surface obtained via a bottom-up approach.

    PubMed

    Rahma, Hakim; Buffeteau, Thierry; Belin, Colette; Le Bourdon, Gwenaëlle; Degueil, Marie; Bennetau, Bernard; Vellutini, Luc; Heuzé, Karine

    2013-08-14

    The covalent grafting on silica surfaces of a functional dendritic organosilane coupling agent inserted, in a long alkyl chain monolayer, is described. In this paper, we show that depending on experimental parameters, particularly the solvent, it is possible to obtain a nanodesigned surface via a bottom-up approach. Thus, we succeed in the formation of both homogeneous dense monolayer and a heterogeneous dense monolayer, the latter being characterized by a nanosized volcano-type pattern (4-6 nm of height, 100 nm of width, and around 3 volcanos/μm(2)) randomly distributed over the surface. The dendritic attribute of the grafted silylated coupling agent affords enough anchoring sites to immobilize covalently functional gold nanoparticles (GNPs), coated with amino PEG polymer to resolve the chemical nature of the surfaces and especially the volcano type nanopattern structures of the heterogeneous monolayer. Thus, the versatile surface chemistry developed herein is particularly challenging as the nanodesign is straightforward achieved in a bottom-up approach without any specific lithography device.

  13. Sensorimotor event: an approach to the dynamic, embodied, and embedded nature of sensorimotor cognition

    PubMed Central

    Vilarroya, Oscar

    2014-01-01

    In this paper, I explore the notion of sensorimotor event as the building block of sensorimotor cognition. A sensorimotor event is presented here as a neurally controlled event that recruits those processes and elements that are necessary to address the demands of the situation in which the individual is involved. The notion of sensorimotor event is intended to subsume the dynamic, embodied, and embedded nature of sensorimotor cognition, in agreement with the satisficing and bricoleur approach to sensorimotor cognition presented elsewhere (Vilarroya, 2012). In particular, the notion of sensorimotor event encompasses those relevant neural processes, but also those bodily and environmental elements, that are necessary to deal with the situation in which the individual is involved. This continuum of neural processes as well as bodily and environmental elements can be characterized, and this characterization is considered the basis for the identification of the particular sensorimotor event. Among other consequences, the notion of sensorimotor event suggests a different approach to the classical account of sensory-input mapping onto a motor output. Instead of characterizing how a neural system responds to an external input, the idea defended here is to characterize how system-in-an-environment responds to its antecedent situation. PMID:24427133

  14. CHARACTERIZATION AND MONITORING OF NATURAL ATTENUATION OF CHLORINATED SOLVENTS IN GROUNDWATER: A SYSTEMS APPROACH

    SciTech Connect

    Looney, B; Michael Heitkamp, M; Gary Wein , G; Christopher Bagwell, C; Karen Vangelas, K; Karen-M Adams, K; Tyler Gilmore; Norman Cutshall; David Major; Mike Truex; Todd Wiedemeier; Francis H. Chapelle; Tom Early; Jody Waugh; David Peterson; Mark Ankeny; Claire H. Sink

    2006-08-10

    The objective of this document is to examine the use of a phased approach to characterizing and monitoring (C&M) natural attenuation processes and enhanced attenuation processes and to identify promising tools and techniques by which to accomplish the C&M. We will investigate developing techniques, such as molecular-based assessment tools, and existing tools that traditionally have not been used for monitoring the performance of environmental remediation technologies. Case studies will be used to provide examples of how non-traditional methods are being employed as characterization and monitoring tools to support MNA and EA. The document is not focused on a specific group of readers but rather is broadly directed with the intent that readers may gain information useful to their purposes. Thus, regulators may see some future characterization and monitoring techniques; end users may find novel ways to make MNA or EA more effective or efficient at their site; researchers may identify new areas for development or new and better combinations of existing methods. One consequence of this broad approach is that some readers may find certain sections either too rudimentary or too advanced for their needs. Hopefully, all will be able to use at least some of the document.

  15. An ensemble approach to simulate CO2 emissions from natural fires

    NASA Astrophysics Data System (ADS)

    Eliseev, A. V.; Mokhov, I. I.; Chernokulsky, A. V.

    2014-06-01

    This paper presents ensemble simulations with the global climate model developed at the A. M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences (IAP RAS CM). These simulations are forced by historical reconstructions of concentrations of well-mixed greenhouse gases (CO2, CH4, and N2O), sulfate aerosols (both in the troposphere and stratosphere), extent of crops and pastures, and total solar irradiance for AD 850-2005 (hereafter all years are taken as being AD) and by the Representative Concentration Pathway (RCP) scenarios for the same forcing agents until the year 2300. Our model implements GlobFIRM (Global FIRe Model) as a scheme for calculating characteristics of natural fires. Comparing to the original GlobFIRM model, in our implementation, the scheme is extended by a module accounting for CO2 release from soil during fires. The novel approach of our paper is to simulate natural fires in an ensemble fashion. Different ensemble members in the present paper are constructed by varying the values of parameters of the natural fires module. These members are constrained by the GFED-3.1 data set for the burnt area and CO2 release from fires and further subjected to Bayesian averaging. Our simulations are the first coupled model assessment of future changes in gross characteristics of natural fires. In our model, the present-day (1998-2011) global area burnt due to natural fires is (2.1 ± 0.4) × 106 km2 yr-1 (ensemble mean and intra-ensemble standard deviation are presented), and the respective CO2 emissions to the atmosphere are (1.4 ± 0.2) Pg C yr-1. The latter value is in agreement with the corresponding GFED estimates. The area burnt by natural fires is generally larger than the GFED estimates except in boreal Eurasia, where it is realistic, and in Australia, where it is smaller than these estimates. Regionally, the modelled CO2 emissions are larger (smaller) than the GFED estimates in Europe (in the tropics and north-eastern Eurasia). From

  16. Naturalizing Sense of Agency with a Hierarchical Event-Control Approach

    PubMed Central

    Kumar, Devpriya; Srinivasan, Narayanan

    2014-01-01

    Unraveling the mechanisms underlying self and agency has been a difficult scientific problem. We argue for an event-control approach for naturalizing the sense of agency by focusing on the role of perception-action regularities present at different hierarchical levels and contributing to the sense of self as an agent. The amount of control at different levels of the control hierarchy determines the sense of agency. The current study investigates this approach in a set of two experiments using a scenario containing multiple agents sharing a common goal where one of the agents is partially controlled by the participant. The participant competed with other agents for achieving the goal and subsequently answered questions on identification (which agent was controlled by the participant), the degree to which they are confident about their identification (sense of identification) and the degree to which the participant believed he/she had control over his/her actions (sense of authorship). Results indicate a hierarchical relationship between goal-level control (higher level) and perceptual-motor control (lower level) for sense of agency. Sense of identification ratings increased with perceptual-motor control when the goal was not completed but did not vary with perceptual-motor control when the goal was completed. Sense of authorship showed a similar interaction effect only in experiment 2 that had only one competing agent unlike the larger number of competing agents in experiment 1. The effect of hierarchical control can also be seen in the misidentification pattern and misidentification was greater with the agent affording greater control. Results from the two studies support the event-control approach in understanding sense of agency as grounded in control. The study also offers a novel paradigm for empirically studying sense of agency and self. PMID:24642834

  17. NATURAL RADIOACTIVITY LEVEL AND ELEMENTAL COMPOSITION OF SOIL SAMPLES FROM A HIGH BACKGROUND RADIATION AREA ON EASTERN COAST OF INDIA (ODISHA).

    PubMed

    Sahoo, S K; Kierepko, R; Sorimachi, A; Omori, Y; Ishikawa, T; Tokonami, S; Prasad, G; Gusain, G S; Ramola, R C

    2016-10-01

    A comprehensive study was carried out to determine the radioactivity concentration of soil samples from different sites of a high background radiation area in the eastern coast of India, Odisha state. The dose rate measured in situ varied from 0.25 to 1.2 µSv h(-1) The gamma spectrometry measurements indicated Th series elements as the main contributors to the enhanced level of radiation and allowed the authors to find the mean level of the activity concentration (±SD) for (226)Ra, (228)Th and (40)K as 130±97, 1110±890 and 360±140 Bq kg(-1), respectively. Human exposure from radionuclides occurring outdoor was estimated based on the effective dose rate, which ranged from 0.14±0.02 to 2.15±0.26 mSv and was higher than the UNSCEAR annual worldwide average value 0.07 mSv. Additionally, X-ray fluorescence analysis provided information about the content of major elements in samples and indicated the significant amount of Ti (7.4±4.9 %) in soils.

  18. Raman scattering study of background electron density in InN: a hydrodynamical approach to the LO-phonon-plasmon coupled modes.

    PubMed

    Cuscó, R; Alarcón-Lladó, E; Ibáñez, J; Yamaguchi, T; Nanishi, Y; Artús, L

    2009-10-14

    We use a hydrodynamical approach to analyse the long-wavelength LO-phonon-plasmon coupled modes observed in a set of high-quality MBE-grown InN epilayers with electron densities varying over one order of magnitude, from ∼2 × 10(18) to ∼2 × 10(19)  cm(-3). The samples were characterized by scanning electron microscopy, x-ray diffraction and Hall measurements. The correlation observed between the E(2)(high) mode frequency, and hence residual strain, and the electron density measured in the layers indicates that the differences in background electron density may be associated with threading dislocations. Owing to the low Raman signal, only the L(-) branch of the coupled modes can be unambiguously observed. The frequency of the L(-) Raman peak is, however, sensitive enough to the free electron density to allow its determination from lineshape fits to the spectra. These were carried out using an extended hydrodynamical model. Given the small bandgap energy and large conduction band nonparabolicity of InN, suitable expressions for the optical effective mass and mean square velocity that enter the hydrodynamical model were derived. Electron density values extracted from L(-) lineshape fits agree reasonably well with Hall determinations.

  19. Three approaches to investigating the multidimensional nature of a science assessment

    NASA Astrophysics Data System (ADS)

    Gokiert, Rebecca Jayne

    The purpose of this study was to investigate a multi-method approach for collecting validity evidence about the underlying knowledge and skills measured by a large-scale science assessment. The three approaches included analysis of dimensionality, differential item functioning (DIF), and think-aloud interviews. The specific research questions addressed were: (1) Does the 4-factor model previously found by Hamilton et al. (1995) for the grade 8 sample explain the data? (2) Do the performances of male and female students systematically differ? Are these performance differences captured in the dimensions? (3) Can think-aloud reports aid in the generation of hypotheses about the underlying knowledge and skills that are measured by this test? A confirmatory factor analysis of the 4-factor model revealed good model data fit for both the AB and AC tests. Twenty-four of the 83 AB test items and 16 of the 77 AC test items displayed significant DIF, however, items were found, on average, to favour both males and females equally. There were some systematic differences found across the 4-factors; items favouring males tended to be related to earth and space sciences, stereotypical male related activities, and numerical operations. Conversely, females were found to outperform males on items that required careful reading and attention to detail. Concurrent and retrospective verbal reports (Ericsson & Simon, 1993) were collected from 16 grade 8 students (9 male and 7 female) while they solved 12 DIF items. Four general cognitive processing themes were identified from the student protocols that could be used to explain male and female problem solving. The themes included comprehension (verbal and visual), visualization, background knowledge/experience (school or life), and strategy use. There were systematic differences in cognitive processing between the students that answered the items correctly and the students who answered the items incorrectly; however, this did not always

  20. A global approach to analysis and interpretation of metabolic data for plant natural product discovery.

    PubMed

    Hur, Manhoi; Campbell, Alexis Ann; Almeida-de-Macedo, Marcia; Li, Ling; Ransom, Nick; Jose, Adarsh; Crispin, Matt; Nikolau, Basil J; Wurtele, Eve Syrkin

    2013-04-01

    Discovering molecular components and their functionality is key to the development of hypotheses concerning the organization and regulation of metabolic networks. The iterative experimental testing of such hypotheses is the trajectory that can ultimately enable accurate computational modelling and prediction of metabolic outcomes. This information can be particularly important for understanding the biology of natural products, whose metabolism itself is often only poorly defined. Here, we describe factors that must be in place to optimize the use of metabolomics in predictive biology. A key to achieving this vision is a collection of accurate time-resolved and spatially defined metabolite abundance data and associated metadata. One formidable challenge associated with metabolite profiling is the complexity and analytical limits associated with comprehensively determining the metabolome of an organism. Further, for metabolomics data to be efficiently used by the research community, it must be curated in publicly available metabolomics databases. Such databases require clear, consistent formats, easy access to data and metadata, data download, and accessible computational tools to integrate genome system-scale datasets. Although transcriptomics and proteomics integrate the linear predictive power of the genome, the metabolome represents the nonlinear, final biochemical products of the genome, which results from the intricate system(s) that regulate genome expression. For example, the relationship of metabolomics data to the metabolic network is confounded by redundant connections between metabolites and gene-products. However, connections among metabolites are predictable through the rules of chemistry. Therefore, enhancing the ability to integrate the metabolome with anchor-points in the transcriptome and proteome will enhance the predictive power of genomics data. We detail a public database repository for metabolomics, tools and approaches for statistical analysis

  1. A natural approach to extended Newtonian gravity: tests and predictions across astrophysical scales

    NASA Astrophysics Data System (ADS)

    Mendoza, S.; Hernandez, X.; Hidalgo, J. C.; Bernal, T.

    2011-02-01

    In the pursuit of a general formulation for a modified gravitational theory at the non-relativistic level and as an alternative to the dark matter hypothesis, we construct a model valid over a wide variety of astrophysical scales. Through the inclusion of Milgrom's acceleration constant into a gravitational theory, we show that very general formulae can be constructed for the acceleration felt by a particle. Dimensional analysis shows that this inclusion naturally leads to the appearance of a mass-length scale in gravity, breaking its scale invariance. A particular form of the modified gravitational force is constructed and tested for consistency with observations over a wide range of astrophysical environments, from Solar system to extragalactic scales. We show that over any limited range of physical parameters, which define a specific class of astrophysical objects, the dispersion velocity of a system must be a power law of its mass and size. These powers appear linked together through a natural constraint relation of the theory. This yields a generalized gravitational equilibrium relation valid for all astrophysical systems. A general scheme for treating spherical symmetrical density distributions is presented, which in particular shows that the Fundamental Plane of elliptical galaxies, the Newtonian virial equilibrium, the Tully-Fisher and the Faber-Jackson relations, as well as the scalings observed in local dwarf spheroidal galaxies, are nothing but particular cases of that relation when applied to the appropriate mass-length scales. We discuss the implications of this approach for a modified theory of gravity and emphasize the advantages of working with the force, instead of altering Newton's second law of motion, in the formulation of a gravitational theory.

  2. A global approach to analysis and interpretation of metabolic data for plant natural product discovery†

    PubMed Central

    Hur, Manhoi; Campbell, Alexis Ann; Almeida-de-Macedo, Marcia; Li, Ling; Ransom, Nick; Jose, Adarsh; Crispin, Matt; Nikolau, Basil J.

    2013-01-01

    Discovering molecular components and their functionality is key to the development of hypotheses concerning the organization and regulation of metabolic networks. The iterative experimental testing of such hypotheses is the trajectory that can ultimately enable accurate computational modelling and prediction of metabolic outcomes. This information can be particularly important for understanding the biology of natural products, whose metabolism itself is often only poorly defined. Here, we describe factors that must be in place to optimize the use of metabolomics in predictive biology. A key to achieving this vision is a collection of accurate time-resolved and spatially defined metabolite abundance data and associated metadata. One formidable challenge associated with metabolite profiling is the complexity and analytical limits associated with comprehensively determining the metabolome of an organism. Further, for metabolomics data to be efficiently used by the research community, it must be curated in publically available metabolomics databases. Such databases require clear, consistent formats, easy access to data and metadata, data download, and accessible computational tools to integrate genome system-scale datasets. Although transcriptomics and proteomics integrate the linear predictive power of the genome, the metabolome represents the nonlinear, final biochemical products of the genome, which results from the intricate system(s) that regulate genome expression. For example, the relationship of metabolomics data to the metabolic network is confounded by redundant connections between metabolites and gene-products. However, connections among metabolites are predictable through the rules of chemistry. Therefore, enhancing the ability to integrate the metabolome with anchor-points in the transcriptome and proteome will enhance the predictive power of genomics data. We detail a public database repository for metabolomics, tools and approaches for statistical

  3. Synergistic approach for treatment of chicken coccidiosis using berberine--A plant natural product.

    PubMed

    Malik, Tauseef Ahmad; Kamili, Azra N; Chishti, M Z; Tanveer, Syed; Ahad, Shazia; Johri, R K

    2016-04-01

    Despite the advent of anticoccidial drugs and vaccines, coccidiosis continues to result in substantial economic losses to the poultry industry. Berberine, a natural alkaloid is well known in studies involving synergistic approaches, thereby reducing the dosage of principal drugs. Therefore, a study was designed to see whether a synergistic anticoccidial effect could be obtained between amprolium and berberine, in vivo using broiler chicken. Anticoccidial activity was measured in comparison to the reference drug amprolium on the basis of oocyst output reduction, mean weight gain and feed conversion ratio. Oocyst output was measured using Mc-Masters counting technique. Different combinations of berberine and amprolium were tested and out of which 1:1 ratio was the most effective for controlling these parasites. Oral gavaging of 100(50 + 50) mg/kg body weight of 1:1 ratio of amprolium and berberine caused the equivalent reduction in number of oocysts (38.85 ± 9.61) one day prior to that of standard drug amprolium (49.95 ± 16.65) as well as pure berberine (44.4 ± 9.61) used in the study. Weight gain of birds was also highest in the synergistic group (1547.43 ± 12.86) among all the infected groups. Besides feed conversion ratio in the synergistic group was also better (1.387 ± 0.026). The results of this study proved the effectiveness of both amprolium and berberine and revealed synergism between amprolium and berberine against coccidian oocysts, confirmed by significant reduction in the number of coccidian oocysts shed in the feces, leading to better weight gain and improved feed conversion ratio. The study deep-rooted the synergistic potential of berberine, a natural bioactive compound for controlling a protozoan parasite and the results of this study corroborate with its use for treatment of severe diarrhoea, amoebiasis and intestinal infections.

  4. Natural flood management in Southwell (Nottinghamshire, UK): an interdisciplinary approach in a rural-urban catchment

    NASA Astrophysics Data System (ADS)

    Wells, Josh; Labadz, Jillian; Islam, Mofa; Smith, Amanda; Disney, Andrew; Thorne, Colin

    2017-04-01

    The town of Southwell (Nottinghamshire, UK) is situated within a rural catchment and has experienced multiple flood events. In summer 2013 an extreme event occurred in which 107.6mm of rain fell within two hours, flooding up to 300 homes. As a result, a voluntary flood action group was established in the community (Southwell Flood Forum). An experimental natural flood management research project has been developed within the Potwell Dyke catchment (above Southwell). This has led to the creation of a catchment partnership of relevant stakeholders (academics, community, statutory bodies, local government and conservation organisations). Prior to intervention, water level monitoring was installed at five locations and flows were gauged for approximately one year. Rainfall data are available from the university weather station within the catchment. Ten large woody debris dams were installed on two of the streams within the catchment in summer 2016. In November, a stream restoration took place to reinstate historic meanders and create online storage in a previously ditched channel reach, together with the construction of five earth bunds in the corners of the fields. These interventions are designed to store and slow water whilst promoting ecological gains. The research takes an interdisciplinary approach. The aims are to assess the extent to which natural food management (NFM) can reduce fluvial flood occurrence but also identify and analyse current barriers to NFM uptake. Interviews with landowners in the catchment have taken place. Practitioners have also been interviewed in order to discuss the barriers to current uptake from an industry perspective. This study therefore not only addresses the evidence gap but also draws upon current barriers to advise future NFM projects. This paper will present preliminary findings from the hydrological monitoring and summarise barriers identified and lessons learned from stakeholder engagement activities.

  5. Investigating variations in background response in measurements of downhole natural gamma in a banded iron formation in the Pilbara, Western Australia

    NASA Astrophysics Data System (ADS)

    Murphy, Richard J.; Silversides, Katherine L.

    2017-02-01

    Measurements of downhole natural gamma radiation (NGR) provide important information about the location of shale or clay bands within stratigraphical sequences (e.g. in Banded Iron Formations; BIF). An ability to link NGR with other kinds of measurements that are acquired at greater spatial and stratigraphic resolution, such as those acquired by hyperspectral sensing, would open up possibilities for improving the resolution of boundary models. To do this, measurements made by NGR and hyperspectral sensing must be highly correlated and any inconsistencies between these data must be understood. Observations made from the literature and from NGR measurements made in a BIF formation of the Hamersley Group, Pilbara, Western Australia, suggest that NGR measurements in some sections of ore or BIF are elevated compared with other sections; laboratory assays of drill chips do not however suggest the presence of shale or clay. These apparent inconsistencies were investigated using hyperspectral measurements and chemical assays of rock cores in the laboratory and NGR measurements made in the field. We show that the patterns of elevated NGR were a consistent feature of the stratigraphy for this region. Comparison of NGR and Al2O3 made by laboratory assay and from hyperspectral sensing show that elevated NGR measurements were caused by Uranium which was not associated with the presence of shale. Neither Thorium nor Potassium contributed to the elevated gamma signal in the ore. Thorium was strongly correlated with Al2O3 and was found to provide the best indicator of the presence of shale in the stratigraphy.

  6. An ensemble approach to simulate CO2 emissions from natural fires

    NASA Astrophysics Data System (ADS)

    Eliseev, A. V.; Mokhov, I. I.; Chernokulsky, A. V.

    2014-01-01

    This paper presents ensemble simulations with the global climate model developed at the A. M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences (IAP RAS CM). These simulations were forced by historical reconstruction of external forcings for 850-2005 AD and by the Representative Concentration Pathways (RCP) scenarios till year 2300. Different ensemble members were constructed by varying the governing parameters of the IAP RAS CM module to simulate natural fires. These members are constrained by the GFED-3.1 observational data set and further subjected to Bayesian averaging. This approach allows to select only changes in fire characteristics which are robust within the constrained ensemble. In our simulations, the present-day (1998-2011 AD) global area burnt due to natural fires is (2.1 ± 0.4) × 106 km2 yr-1 (ensemble means and intra-ensemble standard deviations are presented), and the respective CO2 emissions in the atmosphere are (1.4 ± 0.2) PgC yr-1. The latter value is in agreement with the corresponding observational estimates. Regionally, the model underestimates CO2 emissions in the tropics; in the extra-tropics, it underestimates these emissions in north-east Eurasia and overestimates them in Europe. In the 21st century, the ensemble mean global burnt area is increased by 13% (28%, 36%, 51%) under scenario RCP 2.6 (RCP 4.5, RCP 6.0, RCP 8.5). The corresponding global emissions increase is 14% (29%, 37%, 42%). In the 22nd-23rd centuries, under the mitigation scenario RCP 2.6 the ensemble mean global burnt area and respective CO2 emissions slightly decrease, both by 5% relative to their values in year 2100. Under other RCP scenarios, these variables continue to increase. Under scenario RCP 8.5 (RCP 6.0, RCP 4.5) the ensemble mean burnt area in year 2300 is higher by 83% (44%, 15%) than its value in year 2100, and the ensemble mean CO2 emissions are correspondingly higher by 31% (19%, 9%). All changes of natural fire characteristics in

  7. Integrated Metabolomics Approach Facilitates Discovery of an Unpredicted Natural Product Suite from Streptomyces coelicolor M145

    PubMed Central

    Sidebottom, Ashley M.; Johnson, Andrew R.; Karty, Jonathan A.; Trader, Darci J.; Carlson, Erin E.

    2013-01-01

    Natural products exhibit a broad range of biological properties and have been a crucial source of therapeutic agents and novel scaffolds. Although bacterial secondary metabolomes are widely explored, they remain incompletely cataloged by current isolation and characterization strategies. To identify metabolites residing in unexplored chemical space, we have developed an integrated discovery approach that combines bacterial growth perturbation, accurate mass spectrometry, comparative mass spectra data analysis, and fragmentation spectra clustering for the identification of low-abundant, novel compounds from complex biological matrices. In this investigation, we analyzed the secreted metabolome of the extensively studied Actinomycete, Streptomyces coelicolor M145, and discovered a low-abundant suite of 15 tri-hydroxamate, amphiphilic siderophores. Compounds in this class have primarily been observed in marine microorganisms making their detection in the soil-dwelling S. coelicolor M145 significant. At least ten of these ferrioxamine-based molecules are not known to be produced by any organism and none have previously been detected from S. coelicolor M145. In addition, we confirmed the production of ferrioxamine D1, a relatively hydrophilic family member that has not been shown to be biosynthesized by this organism. The identified molecules are part of only a small list of secondary metabolites that have been discovered since sequencing of S. coelicolor M145 revealed that it possessed numerous putative secondary metabolite-producing gene clusters with no known metabolites. Thus, the identified siderophores represent the unexplored metabolic potential of both well-studied and new organisms that could be uncovered with our sensitive and robust approach. PMID:23777274

  8. Natural killer cells and neuroblastoma: tumor recognition, escape mechanisms, and possible novel immunotherapeutic approaches.

    PubMed

    Bottino, Cristina; Dondero, Alessandra; Bellora, Francesca; Moretta, Lorenzo; Locatelli, Franco; Pistoia, Vito; Moretta, Alessandro; Castriconi, Roberta

    2014-01-01

    Neuroblastoma (NB) is the most common extra-cranial solid tumor of childhood and arises from developing sympathetic nervous system. Most primary tumors localize in the abdomen, the adrenal gland, or lumbar sympathetic ganglia. Amplification in tumor cells of MYCN, the major oncogenic driver, patients' age over 18 months, and the presence at diagnosis of a metastatic disease (stage IV, M) identify NB at high risk of treatment failure. Conventional therapies did not significantly improve the overall survival of these patients. Moreover, the limited landscape of somatic mutations detected in NB is hampering the development of novel pharmacological approaches. Major efforts aim to identify novel NB-associated surface molecules that activate immune responses and/or direct drugs to tumor cells and tumor-associated vessels. PVR (Poliovirus Receptor) and B7-H3 are promising targets, since they are expressed by most high-risk NB, are upregulated in tumor vasculature and are essential for tumor survival/invasiveness. PVR is a ligand of DNAM-1 activating receptor that triggers the cytolytic activity of natural killer (NK) cells against NB. In animal models, targeting of PVR with an attenuated oncolytic poliovirus induced tumor regression and elimination. Also B7-H3 was successfully targeted in preclinical studies and is now being tested in phase I/II clinical trials. B7-H3 down-regulates NK cytotoxicity, providing NB with a mechanism of escape from immune response. The immunosuppressive potential of NB can be enhanced by the release of soluble factors that impair NK cell function and/or recruitment. Among these, TGF-β1 modulates the cytotoxicity receptors and the chemokine receptor repertoire of NK cells. Here, we summarize the current knowledge on the main cell surface molecules and soluble mediators that modulate the function of NK cells in NB, considering the pros and cons that must be taken into account in the design of novel NK cell-based immunotherapeutic approaches.

  9. UNCOVERING THE WAVE NATURE OF THE EIT WAVE FOR THE 2010 JANUARY 17 EVENT THROUGH ITS CORRELATION TO THE BACKGROUND MAGNETOSONIC SPEED

    SciTech Connect

    Zhao, X. H.; Feng, X. S.; Jiang, C. W.; Wu, S. T.; Wang, A. H.; Vourlidas, A. E-mail: wus@uah.edu

    2011-12-01

    An EIT wave, which typically appears as a diffuse brightening that propagates across the solar disk, is one of the major discoveries of the Extreme ultraviolet Imaging Telescope on board the Solar and Heliospheric Observatory. However, the physical nature of the so-called EIT wave continues to be debated. In order to understand the relationship between an EIT wave and its associated coronal wave front, we investigate the morphology and kinematics of the coronal mass ejection (CME)-EIT wave event that occurred on 2010 January 17. Using the observations of the SECCHI EUVI, COR1, and COR2 instruments on board the Solar Terrestrial Relations Observation-B, we track the shape and movements of the CME fronts along different radial directions to a distance of about 15 solar radii (R{sub s} ); for the EIT wave, we determine the propagation of the wave front on the solar surface along different propagating paths. The relation between the EIT wave speed, the CME speed, and the local fast-mode characteristic speed is also investigated. Our results demonstrate that the propagation of the CME front is much faster than that of the EIT wave on the solar surface, and that both the CME front and the EIT wave propagate faster than the fast-mode speed in their local environments. Specifically, we show a significant positive correlation between the EIT wave speed and the local fast-mode wave speed in the propagation paths of the EIT wave. Our findings support that the EIT wave under study is a fast-mode magnetohydrodynamic wave.

  10. Uncovering the Wave Nature of the EIT Wave for the 2010 January 17 Event through Its Correlation to the Background Magnetosonic Speed

    NASA Astrophysics Data System (ADS)

    Zhao, X. H.; Wu, S. T.; Wang, A. H.; Vourlidas, A.; Feng, X. S.; Jiang, C. W.

    2011-12-01

    An EIT wave, which typically appears as a diffuse brightening that propagates across the solar disk, is one of the major discoveries of the Extreme ultraviolet Imaging Telescope on board the Solar and Heliospheric Observatory. However, the physical nature of the so-called EIT wave continues to be debated. In order to understand the relationship between an EIT wave and its associated coronal wave front, we investigate the morphology and kinematics of the coronal mass ejection (CME)-EIT wave event that occurred on 2010 January 17. Using the observations of the SECCHI EUVI, COR1, and COR2 instruments on board the Solar Terrestrial Relations Observation-B, we track the shape and movements of the CME fronts along different radial directions to a distance of about 15 solar radii (Rs ); for the EIT wave, we determine the propagation of the wave front on the solar surface along different propagating paths. The relation between the EIT wave speed, the CME speed, and the local fast-mode characteristic speed is also investigated. Our results demonstrate that the propagation of the CME front is much faster than that of the EIT wave on the solar surface, and that both the CME front and the EIT wave propagate faster than the fast-mode speed in their local environments. Specifically, we show a significant positive correlation between the EIT wave speed and the local fast-mode wave speed in the propagation paths of the EIT wave. Our findings support that the EIT wave under study is a fast-mode magnetohydrodynamic wave.

  11. Theoretical simulations on the antioxidant mechanism of naturally occurring flavonoid: A DFT approach

    NASA Astrophysics Data System (ADS)

    Praveena, R.; Sadasivam, K.

    2016-05-01

    Synthetic antioxidants such as butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) are found to be toxic, hence non-carcinogenic naturally occurring radical scavengers especially flavonoids have gained considerable importance in the past two decades. In the present investigation, the radical scavenging activity of C-glycosyl flavonoids is evaluated using theoretical approach which could broaden its scope in therapeutic applications. Gas and solvent phase studies of structural and molecular characteristics of C-glycosyl flavonoid, isovitexin is investigated through hydrogen atom transfer mechanism (HAT), Electron transfer-proton transfer (ET-PT) and Sequential proton loss electron transfer (SPLET) by Density functional theory (DFT) using hybrid parameters. The computed values of the adiabatic ionization potential, electron affinity, hardness, softness, electronegativity and electrophilic index indicate that isovitexin possess good radical scavenging activity. The behavior of different -OH groups in polyphenolic compounds is assessed by considering electronic effects of the neighbouring groups and the overall geometry of molecule which in turn helps in analyzing the antioxidant capacity of the polyphenolic molecule. The studies indicate that the H-atom abstraction from 4'-OH site is preferred during the radical scavenging process. From Mulliken spin density analysis and FMOs, B-ring is found to be more delocalized center and capable of electron donation. Comparison of antioxidant activity of vitexin and isovitexin leads to the conclusion that isovitexin acts as a better radical scavenger. This is an evidence for the importance of position of glucose unit in the flavonoid.

  12. Two different approaches in skin cancer therapy: using a photosensitizer/a natural product

    NASA Astrophysics Data System (ADS)

    Abraham, Annie; Gayathri, Devi D.; Cibin, T. R.; Ramaiah, D.

    2010-02-01

    This paper deals with two potential modes for the treatment of skin cancer-one a novel approach using a squaraine dye and the other using a natural product- the flavonoid fraction of Saraca asoka. Squaraine dye is a photosensitizing agent, which is preferentially taken up and retained by the tumor cells and when irradiated with high power visible light results in the selective destruction of the tumor cells by photodynamic therapy. The uniqueness of this mode of treatment lies in the selective destruction of tumor cells without affecting the neighbouring normal cells, which is much advantageous over radiation therapy now frequently used. The chemopreventive and therapeutic effects of the plant component are explored as well. The experimental models were Swiss albino mice in which skin tumor was induced by DMBA. Marked reduction in tumor volume and burden in the treated groups were observed. The reversal of biochemical enzyme markers like rhodanese, myeloperoxidase, β-D glucuronidase, lactate dehydrogenase, hexokinase and sialic acid to near normal levels were observed in the PDT and flavonoid fraction treated groups. The live photographs of the experimental animals and histopathological data further support the obtained results. The study assumes importance as it combines a traditional treatment mode and a novel aspect in cancer therapy using the same experimental models. Also this is the first report on PDT using a squaraine dye for skin cancer therapy in vivo.

  13. The Performance of Available Approaches for Quantifying Airborne Exposure to Asbestos Generated from Natural Deposits

    NASA Astrophysics Data System (ADS)

    Berman, D.

    2012-12-01

    General options for quantifying airborne (exposure) concentrations to asbestos include (1) direct measurement, (2) simulation, and (3) emission/dispersion modeling (of measured asbestos concentrations in the source material). Suitable options for particular applications depend on whether one is evaluating current or future and short-term episodic or long-term average exposures. Moreover, because the character and the magnitude of exposure must both be determined for many applications, methods suitable for air- or bulk-phase measurements must exhibit appropriate performance. After all, it is only when we understand precisely what exposure estimates represent that we can interpret them meaningfully. What is known about the suitability and performance of various options for quantifying asbestos exposures generated from natural deposits will be reviewed in this talk with particular emphasis on an approach in which emission and dispersion of asbestos-containing dusts are modeled from bulk-phase measurements collected using the modified elutriator method (a method designed explicitly for this particular application).

  14. Numerical study of natural convection within a wavy enclosure using meshfree approach: effect of corner heating.

    PubMed

    Singh, Sonam; Bhargava, R

    2014-01-01

    This paper presents a numerical study of natural convection within a wavy enclosure heated via corner heating. The considered enclosure is a square enclosure with left wavy side wall. The vertical wavy wall of the enclosure and both of the corner heaters are maintained at constant temperature, T c and T h , respectively, with T h > T c while the remaining horizontal, bottom, top and side walls are insulated. A penalty element-free Galerkin approach with reduced gauss integration scheme for penalty terms is used to solve momentum and energy equations over the complex domain with wide range of parameters, namely, Rayleigh number (Ra), Prandtl number (Pr), and range of heaters in the x- and y-direction. Numerical results are represented in terms of isotherms, streamlines, and Nusselt number. It is observed that the rate of heat transfer depends to a great extent on the Rayleigh number, Prandtl number, length of the corner heaters and the shape of the heat transfer surface. The consistent performance of the adopted numerical procedure is verified by comparison of the results obtained through the present meshless technique with those existing in the literature.

  15. Numerical Study of Natural Convection within a Wavy Enclosure Using Meshfree Approach: Effect of Corner Heating

    PubMed Central

    Singh, Sonam; Bhargava, R.

    2014-01-01

    This paper presents a numerical study of natural convection within a wavy enclosure heated via corner heating. The considered enclosure is a square enclosure with left wavy side wall. The vertical wavy wall of the enclosure and both of the corner heaters are maintained at constant temperature, Tc and Th, respectively, with Th > Tc while the remaining horizontal, bottom, top and side walls are insulated. A penalty element-free Galerkin approach with reduced gauss integration scheme for penalty terms is used to solve momentum and energy equations over the complex domain with wide range of parameters, namely, Rayleigh number (Ra), Prandtl number (Pr), and range of heaters in the x- and y-direction. Numerical results are represented in terms of isotherms, streamlines, and Nusselt number. It is observed that the rate of heat transfer depends to a great extent on the Rayleigh number, Prandtl number, length of the corner heaters and the shape of the heat transfer surface. The consistent performance of the adopted numerical procedure is verified by comparison of the results obtained through the present meshless technique with those existing in the literature. PMID:24672383

  16. Discover natural compounds as potential phosphodiesterase-4B inhibitors via computational approaches.

    PubMed

    Li, Jing; Zhou, Nan; Liu, Wen; Li, Jianzong; Feng, Yu; Wang, Xiaoyun; Wu, Chuanfang; Bao, Jinku

    2016-05-01

    cAMP, intracellular cyclic adenosine monophosphate, is a ubiquitous second messenger that plays a key role in many physiological processes. PDE4B which can reduce the cAMP level by hydrolyzing cAMP to 5'-AMP has become a therapeutic target for the treatment of human diseases such as respiratory disorders, inflammation diseases, neurological and psychiatric disorders. However, the use of currently available PDE4B inhibitors is restricted due to serious side effects caused by targeting PDE4D. Hence, we are attempting to find out subfamily-selective PDE4B inhibitors from natural products, using computer-aided approaches such as virtual screening, docking, and molecular dynamics simulation. Finally, four potential PDE4B-selective inhibitors (ZINC67912770, ZINC67912780, ZINC72320169, and ZINC28882432) were found. Compared to the reference drug (roflumilast), they scored better during the virtual screening process. Binding free energy for them was -317.51, -239.44, -215.52, and -165.77 kJ/mol, better than -129.05 kJ/mol of roflumilast. The pharmacophore model of the four candidate inhibitors comprised six features, including one hydrogen bond donor, four hydrogen bond acceptors, and one aromatic ring feature. It is expected that our study will pave the way for the design of potent PDE4B-selective inhibitors of new drugs to treat a wide variety of diseases such as asthma, COPD, psoriasis, depression, etc.

  17. Using indicators to assess physical vulnerability and resilience to natural hazards: a combined approach

    NASA Astrophysics Data System (ADS)

    Papathoma-Koehle, Maria; Thaler, Thomas; Fuchs, Sven

    2017-04-01

    Societies will have to live with changing environmental conditions and, therefore, they need to build resilience by reducing vulnerabilities to natural hazards. Successful implementation of strategies for disaster risk reduction requires the understanding and analysis of physical vulnerability and resilience of the built environment. The main objective of the presented research is the development of a methodological framework and toolbox which supports mountain hazard risk management through understanding and including resilience and vulnerability indicators of the built environment in risk management plans. These indicators are selected in terms of two temporal dimensions: vulnerability (as lack of physical ex-ante robustness) and resilience (as the ex-post ability and required time to return to a fully functional condition). An enhanced method using vulnerability indicators for the assessment of physical vulnerability of buildings exposed to mountain hazards is presented here. The approach builds on an existing tool for vulnerability assessment and damage documentation which combines well established methods such as vulnerability curves and indicators. It is based on the consideration of a number of structural characteristics of the buildings as well as the intensity of the process to assign a physical vulnerability index for each building. Moreover, indicators representing the physical resilience of the building are also included. Preliminary results focusing on buildings from the European Alps.

  18. Theoretical simulations on the antioxidant mechanism of naturally occurring flavonoid: A DFT approach

    SciTech Connect

    Praveena, R.; Sadasivam, K.

    2016-05-06

    Synthetic antioxidants such as butylated hydroxyanisole (BHA) and butylated hydroxytoluene (BHT) are found to be toxic, hence non-carcinogenic naturally occurring radical scavengers especially flavonoids have gained considerable importance in the past two decades. In the present investigation, the radical scavenging activity of C-glycosyl flavonoids is evaluated using theoretical approach which could broaden its scope in therapeutic applications. Gas and solvent phase studies of structural and molecular characteristics of C-glycosyl flavonoid, isovitexin is investigated through hydrogen atom transfer mechanism (HAT), Electron transfer-proton transfer (ET–PT) and Sequential proton loss electron transfer (SPLET) by Density functional theory (DFT) using hybrid parameters. The computed values of the adiabatic ionization potential, electron affinity, hardness, softness, electronegativity and electrophilic index indicate that isovitexin possess good radical scavenging activity. The behavior of different –OH groups in polyphenolic compounds is assessed by considering electronic effects of the neighbouring groups and the overall geometry of molecule which in turn helps in analyzing the antioxidant capacity of the polyphenolic molecule. The studies indicate that the H–atom abstraction from 4’–OH site is preferred during the radical scavenging process. From Mulliken spin density analysis and FMOs, B–ring is found to be more delocalized center and capable of electron donation. Comparison of antioxidant activity of vitexin and isovitexin leads to the conclusion that isovitexin acts as a better radical scavenger. This is an evidence for the importance of position of glucose unit in the flavonoid.

  19. Identification of PPARγ Agonists from Natural Sources Using Different In Silico Approaches.

    PubMed

    El-Houri, Rime B; Mortier, Jérémie; Murgueitio, Manuela S; Wolber, Gerhard; Christensen, Lars P

    2015-04-01

    Peroxisome proliferator-activated receptor γ plays an important role in lipid and glucose homeostasis and is the target of many drug discovery investigations because of its role in diseases such as type 2 diabetes. Activation of peroxisome proliferator-activated receptor γ by agonists leads to a conformational change in the ligand-binding domain altering the transcription of several target genes involved in glucose and lipid metabolism, resulting in, for example, facilitation of glucose and lipid uptake and amelioration of insulin resistance, and other effects that are important in the treatment of type 2 diabetes. Peroxisome proliferator-activated receptor γ partial agonists are compounds with diminished agonist efficacy compared to full agonists; however, they maintain the antidiabetic effect of full agonists but do not induce the same magnitude of side effects. This mini-review gives a short introduction to in silico screening methods and recent research advances using computational approaches to identify peroxisome proliferator-activated receptor γ agonists, especially partial agonists, from natural sources and how these ligands bind to the peroxisome proliferator-activated receptor γ in order to better understand their biological effects. Georg Thieme Verlag KG Stuttgart · New York.

  20. A simplified approach for solving coagulation-diffusion equation to estimate atmospheric background particle number loading factors contributed by emissions from localized sources

    NASA Astrophysics Data System (ADS)

    Anand, S.; Mayya, Y. S.

    2011-08-01

    Coagulation and condensation/evaporation combined with atmospheric dispersion are the main processes responsible for the evolution of aerosol particle size distributions and number concentrations emitted from localized sources. A crucial question is: what fraction of freshly emitted particles survive intra-coagulation effect to persist in the atmosphere and become available for further interaction with background aerosols?. The difficulty in estimating this quantity, designated as the number survival fraction, arises due chiefly to the joint action of atmospheric diffusion with nonlinear coagulation effects which are computationally intensive to handle. We provide a simplified approach to evaluate this quantity in the context of instantaneous (puff) and continuous (plume) releases based on a reduction of the respective coagulation-diffusion equations under the assumption of a constant coagulation kernel ( K). The condensation/evaporation processes, being number conserving, are not included in the study. The approach consists of constructing moment equations for the evolution of number concentration and variance of the spatial extension of puff or plume in terms of either time or downstream distance. The puff model, applicable to instantaneous releases is solved within a 3-D, spherically symmetric framework, under an additional assumption of a constant diffusion coefficient ( D) which renders itself amenable to a closed form solution that provides a benchmark for developing the solution to the plume model. The latter case, corresponding to continuous releases, is discussed within a 2-D framework under the assumptions of constant advection velocity ( U) and space dependent diffusion coefficient expressed in terms of turbulent energy dissipation rate ( ɛ). The study brings out the special effect of the coagulation-induced flattening of the spatial concentration profiles because of which particle sizes will be larger at the centre of a Gaussian puff. For a puff of

  1. Taming the Wild: Approaches to Nature in Japanese Early Childhood Education

    ERIC Educational Resources Information Center

    Burke, Rachael S.

    2014-01-01

    The Japanese early childhood curriculum provides ample opportunities for children to interact with nature and to learn about natural phenomena. However, using Kalland (1995) and Martinez's (2008) theories about Japanese constructions of nature, this paper argues that most Japanese early childhood experiences do not constitute direct contact with…

  2. Multiperiod Adaptive Control of the Wellhead Price of Natural Gas: A Bayesian Decision Theoretic Approach.

    DTIC Science & Technology

    of natural gas . A mathematical model is first formulated which can probabilistically predict the magnitude of the additions to natural gas reserves...and the supply of produced gas due to new contracts for specified values of the wellhead price of natural gas in each range of values assumed by these

  3. The Concept of Human Nature in Three Cultures: A Developmental Approach.

    ERIC Educational Resources Information Center

    Oerter, Rolf

    This study compares the concept of human nature in Germany, Java, and the United States. The study assumes cross-cultural similarities in the formal structure of the concept of human nature, while hypothesizing variation in content, for example, in the value systems. Four components of the concept of human nature were presented (personality…

  4. Hanford Site background: Part 1, Soil background for nonradioactive analytes. Revision 1, Volume 1

    SciTech Connect

    Not Available

    1993-04-01

    The determination of soil background is one of the most important activities supporting environmental restoration and waste management on the Hanford Site. Background compositions serve as the basis for identifying soil contamination, and also as a baseline in risk assessment processes used to determine soil cleanup and treatment levels. These uses of soil background require an understanding of the extent to which analytes of concern occur naturally in the soils. This report documents the results of sampling and analysis activities designed to characterize the composition of soil background at the Hanford Site, and to evaluate the feasibility for use as Sitewide background. The compositions of naturally occurring soils in the vadose Zone have been-determined for-nonradioactive inorganic and organic analytes and related physical properties. These results confirm that a Sitewide approach to the characterization of soil background is technically sound and is a viable alternative to the determination and use of numerous local or area backgrounds that yield inconsistent definitions of contamination. Sitewide soil background consists of several types of data and is appropriate for use in identifying contamination in all soils in the vadose zone on the Hanford Site. The natural concentrations of nearly every inorganic analyte extend to levels that exceed calculated health-based cleanup limits. The levels of most inorganic analytes, however, are well below these health-based limits. The highest measured background concentrations occur in three volumetrically minor soil types, the most important of which are topsoils adjacent to the Columbia River that are rich in organic carbon. No organic analyte levels above detection were found in any of the soil samples.

  5. Mapping Natural Terroir Units using a multivariate approach and legacy data

    NASA Astrophysics Data System (ADS)

    Priori, Simone; Barbetti, Roberto; L'Abate, Giovanni; Bucelli, Piero; Storchi, Paolo; Costantini, Edoardo A. C.

    2014-05-01

    Natural Terroir Unit (NTU) is a volume of earth's biosphere that is characterized by a stable set of variables related to the topography, climate, geology and soil. Methods to study the association soil-climate-vines are numerous, but the main question is always: which variables are actually important for the quality and the typicality of grapevines, and then wine, for a particular scale? This work aimed to setting up a multivariate methodology to define viticultural terroirs at the province scale (1:125,000), using viticultural and oenological legacy data. The study area was the Siena province in the Tuscany region (Central Italy). The reference grapevine cultivar was "Sangiovese", which is the most important cultivar of the region. The methodology was based upon the creation of a GIS storing several viticultural and oenological legacy data of 55 experimental vineyards (vintages between 1989-2009), the long term climate data, the digital elevation model, the soil-landscapes (land systems) and the soil profiles with the soil analysis. The selected viticultural and oenological parameters were: must sugar content, sugar accumulation rate from veraison to harvest, must titratable acidity, grape yield per vine, number of bunches for vine, mean bunch weight, and mean weight of berries. The environmental parameters related to viticulture, selected by an explorative PCA, were: elevation, mean annual temperature, mean soil temperature, annual precipitation, clay, sand and gravel content of soils, soil water availability, redoximorphic features and rooting depth. The geostatistical models of the variables interpolation were chosen on the best of mean standardize error, obtained by the cross-validation, between "Simple cokriging with varying local mean", "Multicollocated simple cokriging with varying local mean" and "Regression kriging". These variables were used for a k-means clustering aimed to map the Natural Terroirs Units (NTUs). The viticultural areas of Siena province

  6. Tailoring online information retrieval to user's needs based on a logical semantic approach to natural language processing and UMLS mapping.

    PubMed

    Kossman, Susan; Jones, Josette; Brennan, Patricia Flatley

    2007-10-11

    Depression can derail teenagers' lives and cause serious chronic health problems. Acquiring pertinent knowledge and skills supports care management, but retrieving appropriate information can be difficult. This poster presents a strategy to tailor online information to user attributes using a logical semantic approach to natural language processing (NLP) and mapping propositions to UMLS terms. This approach capitalizes on existing NLM resources and presents a potentially sustainable plan for meeting consumers and providers information needs.

  7. Insightful monitoring of natural flood risk management features using a low-cost and participatory approach

    NASA Astrophysics Data System (ADS)

    Starkey, Eleanor; Barnes, Mhari; Quinn, Paul; Large, Andy

    2016-04-01

    Pressures associated with flooding and climate change have significantly increased over recent years. Natural Flood Risk Management (NFRM) is now seen as being a more appropriate and favourable approach in some locations. At the same time, catchment managers are also encouraged to adopt a more integrated, evidence-based and bottom-up approach. This includes engaging with local communities. Although NFRM features are being more readily installed, there is still limited evidence associated with their ability to reduce flood risk and offer multiple benefits. In particular, local communities and land owners are still uncertain about what the features entail and how they will perform, which is a huge barrier affecting widespread uptake. Traditional hydrometric monitoring techniques are well established but they still struggle to successfully monitor and capture NFRM performance spatially and temporally in a visual and more meaningful way for those directly affected on the ground. Two UK-based case studies are presented here where unique NFRM features have been carefully designed and installed in rural headwater catchments. This includes a 1km2 sub-catchment of the Haltwhistle Burn (northern England) and a 2km2 sub-catchment of Eddleston Water (southern Scotland). Both of these pilot sites are subject to prolonged flooding in winter and flash flooding in summer. This exacerbates sediment, debris and water quality issues downstream. Examples of NFRM features include ponds, woody debris and a log feature inspired by the children's game 'Kerplunk'. They have been tested and monitored over the 2015-2016 winter storms using low-cost techniques by both researchers and members of the community ('citizen scientists'). Results show that monitoring techniques such as regular consumer specification time-lapse cameras, photographs, videos and 'kite-cams' are suitable for long-term and low-cost monitoring of a variety of NFRM features. These techniques have been compared against

  8. New Approaches With Natural Product Drugs for Overcoming Multidrug Resistance in Cancer.

    PubMed

    Dinic, Jelena; Podolski-Renic, Ana; Stankovic, Tijana; Bankovic, Jasna; Pesic, Milica

    2015-01-01

    Resistance to chemotherapeutic drugs is one of the main obstacles to effective cancer treatment. Multidrug resistance (MDR) is defined as resistance to structurally and/or functionally unrelated drugs, and has been extensively investigated for the last three decades. There are two types of MDR: intrinsic and acquired. Tumor microenvironment selection pressure leads to the development of intrinsic MDR, while acquired resistance is a consequence of the administered chemotherapy. A central issue in chemotherapy failure is the existence of heterogeneous populations of cancer cells within one patient and patient-to-patient variability within each type of cancer. Numerous genes and pathways contribute to the development of MDR in cancer. Point mutations, gene amplification or other genetic or epigenetic changes all affect biological functions and may lead to the occurrence of MDR phenotype. Similar to the characteristics of cancerogenesis, the main features of MDR include abnormal tumor vasculature, regions of hypoxia, aerobic glycolysis, and a lower susceptibility to apoptosis. In order to achieve a lethal effect on cancer cells, drugs need to reach their intracellular target molecules. The overexpression of the efflux transporter P-glycoprotein (P-gp) in MDR cancer cells leads to decreased uptake of the drug and intracellular drug accumulation, minimising drug-target interactions. New agents being or inspired by natural products that successfully target these mechanisms are the main subject of this review. Two key approaches in combating MDR in cancer are discussed (i) finding agents that preserve cytotoxicity toward MDR cancer cells; (ii) developing compounds that restore the cytotoxic activity of classic anticancer drugs.

  9. Carbon Balance Assessment of a Natural Steppe of Southern Siberia by Multiple Constraint Approach

    NASA Astrophysics Data System (ADS)

    Belelli, L.; Papale, D.; Reichstein, M.; Vuichard, N.; Tchebakova, N.; Valentini, R.

    2007-12-01

    Steppe ecosystems represent an interesting case in which the assessment of carbon balance may be performed through a cross validation of the eddy covariance measurements against ecological inventory estimates of carbon exchanges (Ehman et al., 2002; Curtis et al., 2002). Indeed, the widespread presence of ideal conditions for the applicability of the eddy covariance technique, as vast and homogeneous grass vegetation cover over flat terrains (Baldocchi, 2003), make steppes a suitable ground to ensure a constrain to flux estimates with independent methodological approaches. We report about the analysis of the carbon cycle of a true steppe ecosystem in southern Siberia during the growing season of 2004 in the framework of the TCOS-Siberia project activities performed by continuous monitoring of CO2 fluxes at ecosystem scale by the eddy covariance method, fortnightly samplings of phytomass, and ingrowth cores extractions for NPP assessment, and weekly measurements of heterotrophic component of soil CO2 effluxes obtained by an experiment of root exclusion. The carbon balance of the monitored natural steppe was, according to micrometeorological measurements, a sink of carbon of 151.7±36.9 gC m-2, cumulated during the growing season from May to September. This result was in agreement with the independent estimate through ecological inventory which yielded a sink of 150.1 gC m-2 although this method was characterized by a large uncertainty \\(±130%\\) considering the 95% confidence interval of the estimate. Uncertainties in belowground process estimates account for a large part of the error. Thus, in particular efforts to better quantify the dynamics of root biomass (growth and turnover) have to be undertaken in order to reduce the uncertainties in the assessment of NPP. This assessment should be preferably based on the application of multiple methods, each one characterized by its own merits and flaws.

  10. The Self-Evolving Cosmos: A Phenomenological Approach to Nature's Unity-in-Diversity

    NASA Astrophysics Data System (ADS)

    Rosen, Steven M.

    ch. 1. Introduction: individuation and the quest for unity -- ch. 2. The obstacle to unification in modern physics. 2.1. Introduction. 2.2. Does contemporary mathematical physics actually depart from the classical formulation? -- ch. 3. The phenomenological challenge to the classical formula -- ch. 4. Topological phenomenology. 4.1. Introduction. 4.2. Phenomenological intuition, topology, and the Klein bottle. 4.3. The physical significance of the Klein bottle -- ch. 5. The dimensional family of topological spinors. 5.1. Generalization of intuitive topology. 5.2. Topodimensional spin matrix -- ch. 6. Basic principles of dimensional transformation. 6.1. Synsymmetry and the self-transformation of space. 6.2. From symmetry breaking to dimensional generation. 6.3. The three basic stages of dimensional generation. 6.4. Kleinian topogeny -- ch. 7. Waves carrying waves: the co-evolution of lifeworlds -- ch. 8. The forces of nature. 8.1. The phenomenon of light. 8.2. Phenomenological Kaluza-Klein theory. 8.3. Summary comparison of conventional and topo-phenomenological approaches to Kaluza-Klein theory -- ch. 9. Cosmogony, symmetry, and phenomenological intuition. 9.1. Conventional view of the evolving cosmos. 9.2. The problem of symmetry. 9.3. A new kind of clarity -- ch. 10. The self-evolving cosmos. 10.1. Introduction to the cosmogonic matrix. 10.2. Overview of cosmic evolution. 10.3. The role of the fermions in dimensional generation. 10.4. Projective stages of cosmogony: dimensional divergence. 10.5. Proprioceptive stages of cosmogony: dimensional convergence. 10.6. Conclusion: wider horizons of cosmic evolution -- ch. 11. The psychophysics of cosmogony. 11.1. Psychical aspects of the fundamental particles. 11.2. Toward a reflexive physics. 11.3. Concretization of the self-evolving cosmos.

  11. How Should We Screen for Depression Following a Natural Disaster? An ROC Approach to Post-Disaster Screening in Adolescents and Adults

    PubMed Central

    Cohen, Joseph R.; Adams, Zachary W.; Menon, Suvarna V.; Youngstrom, Eric A.; Bunnell, Brian E.; Acierno, Ron; Ruggiero, Kenneth J.; Danielson, Carla Kmett

    2016-01-01

    Background The present study’s aim was to provide the foundation for an efficient, empirically based protocol for depression screening following a natural disaster. Utilizing a Receiver Operating Characteristic (ROC) analytic approach, the study tested a) what specific disaster-related stressors (i.e., property damage, loss of basic services) and individual-related constructs (i.e., PTSD symptoms, trauma history, social support) conveyed the greatest risk for post-natural disaster depression, b) specific cutoff scores across these measures, and c) whether the significance or cutoff scores for each construct varied between adolescents and adults. Methods Structured phone-based clinical interviews were conducted with 2,000 adolescents who lived through a tornado and 1,543 adults who survived a hurricane. Results Findings suggested that in both adolescents and adults, individual-related constructs forecasted greater risk for depressive symptoms following a natural disaster compared to disaster-related stressors. Furthermore, trauma history and PTSD symptoms were particularly strong indicators for adolescent depressive symptoms compared to adult depressive symptoms. Adolescents and adults who reported vulnerable scores for social support, trauma history, and lifetime PTSD symptoms were approximately twice as likely to present as depressed following the natural disaster. Limitations Findings from the present study were limited to post-disaster assessments and based on self-reported functioning 6–12 months following the natural disaster. Conclusions The present study synthesizes the extensive body of research on post-disaster functioning by providing a clear framework for which questions may be most important to ask when screening for depression following a natural disaster. PMID:27259082

  12. Nonthermal cosmic neutrino background

    NASA Astrophysics Data System (ADS)

    Chen, Mu-Chun; Ratz, Michael; Trautner, Andreas

    2015-12-01

    We point out that, for Dirac neutrinos, in addition to the standard thermal cosmic neutrino background (C ν B ), there could also exist a nonthermal neutrino background with comparable number density. As the right-handed components are essentially decoupled from the thermal bath of standard model particles, relic neutrinos with a nonthermal distribution may exist until today. The relic density of the nonthermal (nt) background can be constrained by the usual observational bounds on the effective number of massless degrees of freedom Neff and can be as large as nν nt≲0.5 nγ. In particular, Neff can be larger than 3.046 in the absence of any exotic states. Nonthermal relic neutrinos constitute an irreducible contribution to the detection of the C ν B and, hence, may be discovered by future experiments such as PTOLEMY. We also present a scenario of chaotic inflation in which a nonthermal background can naturally be generated by inflationary preheating. The nonthermal relic neutrinos, thus, may constitute a novel window into the very early Universe.

  13. Complementary Approaches to Teaching Nature of Science: Integrating Student Inquiry, Historical Cases, and Contemporary Cases in Classroom Practice

    ERIC Educational Resources Information Center

    Allchin, Douglas; Andersen, Hanne Moller; Nielsen, Keld

    2014-01-01

    Research has now demonstrated that students can learn nature of science concepts variously through student-led investigations, contemporary cases, and historical cases. Here we articulate more precisely the merits, deficits, and context of each approach and begin to profile how to integrate them as complementary methods. Emphasis now needs to…

  14. Do Pre-Service Science Teachers Have Understanding of the Nature of Science?: Explicit-Reflective Approach

    ERIC Educational Resources Information Center

    Örnek, Funda; Turkey, Kocaeli

    2014-01-01

    Current approaches in Science Education attempt to enable students to develop an understanding of the nature of science, develop fundamental scientific concepts, and develop the ability to structure, analyze, reason, and communicate effectively. Students pose, solve, and interpret scientific problems, and eventually set goals and regulate their…

  15. Do Pre-Service Science Teachers Have Understanding of the Nature of Science?: Explicit-Reflective Approach

    ERIC Educational Resources Information Center

    Örnek, Funda; Turkey, Kocaeli

    2014-01-01

    Current approaches in Science Education attempt to enable students to develop an understanding of the nature of science, develop fundamental scientific concepts, and develop the ability to structure, analyze, reason, and communicate effectively. Students pose, solve, and interpret scientific problems, and eventually set goals and regulate their…

  16. Action with Friction: A Transactional Approach to Toddlers' Physical Meaning Making of Natural Phenomena and Processes in Preschool

    ERIC Educational Resources Information Center

    Klaar, Susanne; Ohman, Johan

    2012-01-01

    Research into preschool education has paid a lot of attention to investigating children's conceptual development and cognitive learning about nature, with methods based on observations and verbal interviews before and after a teaching period. The purpose of this study has been to present and illustrate an approach that facilitates the analysis of…

  17. Complementary Approaches to Teaching Nature of Science: Integrating Student Inquiry, Historical Cases, and Contemporary Cases in Classroom Practice

    ERIC Educational Resources Information Center

    Allchin, Douglas; Andersen, Hanne Moller; Nielsen, Keld

    2014-01-01

    Research has now demonstrated that students can learn nature of science concepts variously through student-led investigations, contemporary cases, and historical cases. Here we articulate more precisely the merits, deficits, and context of each approach and begin to profile how to integrate them as complementary methods. Emphasis now needs to…

  18. Effectiveness of the scientific inquiry approach in teaching natural science to first-year college students in a Philippine university

    NASA Astrophysics Data System (ADS)

    Jimenez, Luzviminda Miano

    Student-centered approaches to learning are aligned with the Constructivist Model and have been the focus of much recent science education research in the United States. It is based on the premise that students learn better when they are actively engaged and given the opportunity to construct their own knowledge. In addition, the search continues for effective science curricular and pedagogical approaches that will provide adequate understanding of the nature of science and development of positive attitudes. This study investigated the effectiveness of the scientific inquiry approach, which is a student-centered style of teaching, in improving students' attitudes and understanding of the nature of science. The scientific inquiry approach was used in the teaching of Natural Science in a Philippine university. Pre- and post-surveys on attitude and views about science were administered to 767 first year college students enrolled in the course. The results of the surveys revealed significant differences in both students' views and their attitudes before and after instruction. The overall trend of respondents' answers was changed from a mixed-folk (unscientific) direction to a mixed-expert (scientific) direction. Thus, the study concludes that the scientific inquiry style of teaching makes a significant impact in changing or improving students' attitudes and understanding about the nature of science. This study also showed a positive correlation between students' views and their attitudes toward science.

  19. Sacred Places in Nature: A Unitive Theme for a Transpersonal Approach to Environmental Education.

    ERIC Educational Resources Information Center

    Swan, Jim

    1983-01-01

    Provides background information on and development and use of mental imagery exercises in environmental education. The exercises are designed to help people make contact with those symbolic forms which then actualize certain aspects of their personality. (JN)

  20. Sacred Places in Nature: A Unitive Theme for a Transpersonal Approach to Environmental Education.

    ERIC Educational Resources Information Center

    Swan, Jim

    1983-01-01

    Provides background information on and development and use of mental imagery exercises in environmental education. The exercises are designed to help people make contact with those symbolic forms which then actualize certain aspects of their personality. (JN)

  1. Understanding the social acceptability of natural resource decisionmaking processes by using a knowledge base modeling approach.

    Treesearch

    Christina Kakoyannis; Bruce Shindler; George. Stankey

    2001-01-01

    Natural resource managers are being confronted with increasing conflict and litigation with those who find their management plans unacceptable. Compatible and sustainable management decisions necessitate that natural resource agencies generate plans that are not only biologically possible and economically feasible but also socially acceptable. Currently, however, we...

  2. An empirical approach for estimating natural regeneration for the Forest Vegetation Simulator

    Treesearch

    Don Vandendriesche

    2010-01-01

    The “partial” establishment model that is available for most Forest Vegetation Simulator (FVS) geographic variants does not provide an estimate of natural regeneration. Users are responsible for supplying this key aspect of stand development. The process presented for estimating natural regeneration begins by summarizing small tree components based on observations from...

  3. Using Behavior Setting Theory To Define Natural Settings: A Family-Centered Approach.

    ERIC Educational Resources Information Center

    Tisot, Caroline Monforte; Thurman, S. Kenneth

    2002-01-01

    This article addresses the need to refocus the view of the natural environment as a family-chosen placement for early intervention services. Psycho-ecological theories are used to broaden the conception of the natural environment and illuminate possibilities for early intervention that utilize community and home resources while respecting family…

  4. Economic values of metro nature health benefits: A life course approach

    Treesearch

    Kathleen L. Wolf; Marcus K. Measells; Stephen C. Grado; Alicia S.T. Robbins

    2015-01-01

    tThe presence of metro nature enables daily environmental interactions, and a substantial body of evi-dence now demonstrates that nature contact generates extensive psychosocial, cognitive, and physicalhealth and well-being benefits. Estimates of the economic values of such benefits have lagged similarvaluation efforts for environmental services (such as improved air...

  5. From Sequential Extraction to Transport Modeling, Monitored Natural Attenuation as a Remediation Approach for Inorganic Contaminants

    SciTech Connect

    POWELL, KIMBERLYR.

    2004-05-25

    Implementation of monitored natural attenuation (MNA) as a remediation method requires a mechanistic understanding of the natural attenuation processes occurring at a given site. For inorganic contaminants, natural attenuation typically involves a decrease in metal toxicity and/or mobility. These natural processes include dilution, dispersion, sorption (including adsorption, absorption, and precipitation), and redox processes. In order to better quantify these processes in terms of metal availability, sequential extraction experiments were carried out on subsurface soil samples impacted by a low pH, high sulfate, metals (Be, Ni, U, As) plume associated with the long-term operation of a coal plant at the Savannah River Site. These laboratory scale studies provide mechanistic information regarding the solid phases in the soils associated with natural attenuation of the contaminant metals. This data provides input to be evaluated in the definition of the contaminant source term as well as transport of contaminants for site transport models.

  6. Relationship between acoustic measures and speech naturalness ratings in Parkinson's disease: A within-speaker approach.

    PubMed

    Klopfenstein, Marie

    2015-01-01

    This study investigated the acoustic basis of across-utterance, within-speaker variation in speech naturalness for four speakers with dysarthria secondary to Parkinson's disease (PD). Speakers read sentences and produced spontaneous speech. Acoustic measures of fundamental frequency, phrase-final syllable lengthening, intensity and speech rate were obtained. A group of listeners judged speech naturalness using a nine-point Likert scale. Relationships between judgements of speech naturalness and acoustic measures were determined for individual speakers with PD. Relationships among acoustic measures also were quantified. Despite variability between speakers, measures of mean F0, intensity range, articulation rate, average syllable duration, duration of final syllables, vocalic nucleus length of final unstressed syllables and pitch accent of final syllables emerged as possible acoustic variables contributing to within-speaker variations in speech naturalness. Results suggest that acoustic measures correlate with speech naturalness, but in dysarthric speech they depend on the speaker due to the within-speaker variation in speech impairment.

  7. Unified fractional differential approach for transient interporosity flow in naturally fractured media

    NASA Astrophysics Data System (ADS)

    Babak, Petro; Azaiez, Jalel

    2014-12-01

    A unified approach to modeling flows of slightly compressible fluids through naturally fractured media is presented. The unified fractional differential model is derived by combining the flow at micro scale for matrix blocks and macro scale for fractures, using the transient interporosity flow behavior at the interface between matrix blocks and fractures. The derived model is able to unify existing transient interporosity flow models formulated for different shapes of matrix blocks in any medium dimensions. The model is formulated in the form of a fractional order partial differential equation that involves Caputo derivative of order 1/2 with respect to time. Explicit solutions for the unified model are derived for different axisymmetrical spatial domains using Hankel or Hankel-Weber finite or infinite transforms. Comparisons between the predictions of the unified model and those obtained from existing transient interporosity flow models for matrix blocks in the form of slabs, spheres and cylinders are presented. It is shown that the unified fractional derivative model leads to solutions that are very close to those of transient interporosity flow models for fracture-dominant and transitional fracture-to-matrix dominant flow regimes. An analysis of the results of the unified model reveals that the pressure varies linearly with the logarithm of time for different flow regimes, with half slope for the transitional fracture-to-matrix dominant flow regime vs. the fracture and matrix dominant flow regimes. In addition, a new re-scaling that involves the characteristic length in the form of matrix block volume to surface area ratio is derived for the transient interporosity flow models for matrix blocks of different shapes. It is shown that the re-scaled transient interporosity flow models are governed by two dimensionless parameters Θ and Λ compared to only one dimensionless parameter Θ for the unified model. It is shown that the solutions of the transient

  8. An observation-based approach to identify local natural dust events from routine aerosol ground monitoring

    NASA Astrophysics Data System (ADS)

    Tong, D. Q.; Dan, M.; Wang, T.; Lee, P.

    2012-02-01

    Dust is a major component of atmospheric aerosols in many parts of the world. Although there exist many routine aerosol monitoring networks, it is often difficult to obtain dust records from these networks, because these monitors are either deployed far away from dust active regions (most likely collocated with dense population) or contaminated by anthropogenic sources and other natural sources, such as wildfires and vegetation detritus. Here we propose a new approach to identify local dust events relying solely on aerosol mass and composition from general-purpose aerosol measurements. Through analyzing the chemical and physical characteristics of aerosol observations during satellite-detected dust episodes, we select five indicators to be used to identify local dust records: (1) high PM10 concentrations; (2) low PM2.5/PM10 ratio; (3) higher concentrations and percentage of crustal elements; (4) lower percentage of anthropogenic pollutants; and (5) low enrichment factors of anthropogenic elements. After establishing these identification criteria, we conduct hierarchical cluster analysis for all validated aerosol measurement data over 68 IMPROVE sites in the Western United States. A total of 182 local dust events were identified over 30 of the 68 locations from 2000 to 2007. These locations are either close to the four US Deserts, namely the Great Basin Desert, the Mojave Desert, the Sonoran Desert, and the Chihuahuan Desert, or in the high wind power region (Colorado). During the eight-year study period, the total number of dust events displays an interesting four-year activity cycle (one in 2000-2003 and the other in 2004-2007). The years of 2003, 2002 and 2007 are the three most active dust periods, with 46, 31 and 24 recorded dust events, respectively, while the years of 2000, 2004 and 2005 are the calmest periods, all with single digit dust records. Among these deserts, the Chihuahua Desert (59 cases) and the Sonoran Desert (62 cases) are by far the most active

  9. Emerging Approach of Natural Language Processing in Opinion Mining: A Review

    NASA Astrophysics Data System (ADS)

    Kim, Tai-Hoon

    Natural language processing (NLP) is a subfield of artificial intelligence and computational linguistics. It studies the problems of automated generation and understanding of natural human languages. This paper outlines a framework to use computer and natural language techniques for various levels of learners to learn foreign languages in Computer-based Learning environment. We propose some ideas for using the computer as a practical tool for learning foreign language where the most of courseware is generated automatically. We then describe how to build Computer Based Learning tools, discuss its effectiveness, and conclude with some possibilities using on-line resources.

  10. Approach to the organization of knowledge and its use in natural language recall tasks

    SciTech Connect

    Mccalla, G.I.

    1983-01-01

    The viewpoint espoused in this paper is that natural language understanding and production is the action of a number of highly integrated domain-specific specialists. Described first is an object oriented representation scheme which allows these specialists to be built. Discussed next is the organization of these specialists into a four-level goal hierarchy that enables the modelling of natural language conversation. It is shown how the representation and natural language structures can be used to facilitate the recall of earlier natural language conversations. Six specific kinds of recall tasks are outlined in terms of these structures and their occurrence in several legal dialogues is examined. Finally, the need for intelligent garbage collection of old episodic information is pointed out. 38 references.

  11. An Approach for Monitored Natural Attenuation (MNA) at a LUST Site

    EPA Science Inventory

    The primary mechanism for natural attenuation of fuel components in ground water is aerobic and anaerobic biodegradation of the components. Biodegradation reduces the concentration of oxygen, nitrate and sulfate, and increases the concentrations of iron(II) and methane. Changes...

  12. An Approach for Monitored Natural Attenuation (MNA) at a LUST Site

    EPA Science Inventory

    The primary mechanism for natural attenuation of fuel components in ground water is aerobic and anaerobic biodegradation of the components. Biodegradation reduces the concentration of oxygen, nitrate and sulfate, and increases the concentrations of iron(II) and methane. Changes...

  13. Teaching English as a Second Language: Perspectives and Practices. A Series of Six Texts. Background and Approaches: First of a Series.

    ERIC Educational Resources Information Center

    New York State Education Dept., Albany.

    This book is designed to assist those who work with non-English dominant students by providing resource information relevant to second language teaching and learning. The articles in the series encompass both theory and practical learning techniques in six general topics. The articles in the first text of the series, concerning background and…

  14. A Mixed Method Study of Factors Associated with the Academic Achievement of Latina/o College Students from Predominantly Mexican American Backgrounds: A Strengths-Based Approach

    ERIC Educational Resources Information Center

    Lara, Laura G.

    2009-01-01

    Young adults from Latina/o backgrounds draw from cultural assets and wrestle with distinctive challenges as they enter into, study at, and graduate from institutions of higher education. In this investigation, I examined the perspectives of Latina/o college students with low and high academic achievement, focusing on their upbringing within…

  15. The Empty-Pot Healing Approach: Its Origins, Nature, and Practice.

    ERIC Educational Resources Information Center

    Oshodi, John Egbeazien

    1999-01-01

    Describes the Oshodi (J. Oshodi) Empty-Pot Healing Approach (OEPHA), an African-based psychotherapeutic approach that aims to create balance and foster achievement motivation. Illustrates the 11 phases of the OEPHA through the case study of an adult psychotherapeutic client. (SLD)

  16. Improving structural similarity based virtual screening using background knowledge

    PubMed Central

    2013-01-01

    Background Virtual screening in the form of similarity rankings is often applied in the early drug discovery process to rank and prioritize compounds from a database. This similarity ranking can be achieved with structural similarity measures. However, their general nature can lead to insufficient performance in some application cases. In this paper, we provide a link between ranking-based virtual screening and fragment-based data mining methods. The inclusion of binding-relevant background knowledge into a structural similarity measure improves the quality of the similarity rankings. This background knowledge in the form of binding relevant substructures can either be derived by hand selection or by automated fragment-based data mining methods. Results In virtual screening experiments we show that our approach clearly improves enrichment factors with both applied variants of our approach: the extension of the structural similarity measure with background knowledge in the form of a hand-selected relevant substructure or the extension of the similarity measure with background knowledge derived with data mining methods. Conclusion Our study shows that adding binding relevant background knowledge can lead to significantly improved similarity rankings in virtual screening and that even basic data mining approaches can lead to competitive results making hand-selection of the background knowledge less crucial. This is especially important in drug discovery and development projects where no receptor structure is available or more frequently no verified binding mode is known and mostly ligand based approaches can be applied to generate hit compounds. PMID:24341870

  17. A new integrated program for natural product development and the value of an ethnomedical approach.

    PubMed

    Schuster, B G

    2001-01-01

    There is a need for less expensive alternative therapies, especially in the treatment of chronic illnesses. This presentation addresses the issues inherent in the use of natural products in a drug-discovery or development program and reviews a model program developed by the U.S. National Institutes of Health (NIH) and administered by the Fogarty International Center at the NIH. Eighty percent (80%) of the world's population relies on medicinal plants for their primary health care. The World Health Organization has been promoting traditional medicine as a source of less expensive, comprehensive medical care, especially in developing countries. Natural products have also been successful in drug development. Over 50% of the best-selling pharmaceuticals in use today are derived from natural products. In a natural-product drug development program, it is the diversity of the natural products that is especially interesting. Thanks to technologic advances, now is a good time to be looking for new drugs in the natural-product arena. But there are major hurdles to overcome in a natural-products development program, namely, time-to-lead, supply, and ownership. Time-to-lead is complex because most natural products are mixtures or crude extracts. It can be very difficult to isolate the active principles and elucidate their structures. The difficulty of obtaining sufficient supply is often given as a reason for not becoming involved in natural-product drug development or discovery. This presentation details some ways these seeming hurdles can be overcome. The concept of ownership has changed dramatically in recent years. Until recently, genetic resources were considered to belong to no one and to therefore be the heritage of everyone. The United Nations Convention on Biodiversity and the meetings in Rio de Janeiro in 1992, redefined biodiversity ownership. Genetic biodiversity has a potential value and belongs to the country of origin. The International Conservation of

  18. Natural attenuation of metals and radionuclides -- An overview of the Sandia/DOE approach

    SciTech Connect

    Waters, R.D.; Brady, P.V.; Borns, D.J.

    1998-02-01

    Sandia National Laboratories is developing guidelines that outline the technical basis for relying on natural attenuation for the remediation of metals and radionuclide-contaminated soils and groundwaters at US Department of Energy (DOE) sites for those specific cases where natural processes are effective at ameliorating soil and groundwater toxicity. Remediation by monitored natural attenuation (MNA) requires a clear identification of the specific reaction(s) by which contaminant levels are made less available as well as considerable long-term monitoring. Central to MNA is the development of a conceptual model describing the biogeochemical behavior of contaminant(s) in the subsurface. The conceptual model will be used to make testable predictions of contaminant availability over time. In many cases, comparison between this prediction and field measurements will provide the test of whether MNA is to be implemented. As a result, development of the conceptual model should guide site characterization activities as well as long-term monitoring.

  19. The Right "Fit": Exploring Science Teacher Candidates' Approaches to Natural Selection Within a Clinical Simulation

    NASA Astrophysics Data System (ADS)

    Dotger, Benjamin; Dotger, Sharon; Masingila, Joanna; Rozelle, Jeffrey; Bearkland, Mary; Binnert, Ashley

    2017-04-01

    Teachers and students struggle with the complexities surrounding the evolution of species and the process of natural selection. This article examines how science teacher candidates (STCs) engage in a clinical simulation that foregrounds two common challenges associated with natural selection—students' understanding of "survival of the fittest" and the variation of species over time. We outline the medical education pedagogy of clinical simulations and its recent diffusion to teacher education. Then, we outline the study that situates each STC in a one-to-one interaction with a standardized student who is struggling to accurately interpret natural selection concepts. In simulation with the standardized student, each STC is challenged to recognize content misconceptions and respond with appropriate instructional strategies and accurate explanations. Findings and implications center on the STCs' instructional practices in the simulation and the use of clinical learning environments to foster science teacher learning.

  20. A New Approach to Predict the Fish Fillet Shelf-Life in Presence of Natural Preservative Agents.

    PubMed

    Giuffrida, Alessandro; Giarratana, Filippo; Valenti, Davide; Muscolino, Daniele; Parisi, Roberta; Parco, Alessio; Marotta, Stefania; Ziino, Graziella; Panebianco, Antonio

    2017-04-13

    Three data sets concerning the behaviour of spoilage flora of fillets treated with natural preservative substances (NPS) were used to construct a new kind of mathematical predictive model. This model, unlike other ones, allows expressing the antibacterial effect of the NPS separately from the prediction of the growth rate. This approach, based on the introduction of a parameter into the predictive primary model, produced a good fitting of observed data and allowed characterising quantitatively the increase of shelf-life of fillets.

  1. MicroRNAs: association with radioresistant and potential uses of natural remedies as green gene therapeutic approaches.

    PubMed

    Jothy, Subramanion L; Chen, Yeng; Vijayarathna, Soundararajan; Kanwar, Jagat R; Sasidharan, Sreenivasan

    2015-01-01

    Radiotherapy plays an essential primary role in cancer patients. Regardless of its significant advances in treatment options, tumor recurrence and radio-resistance in cancer cells still occur in a high percentage of patients. Furthermore, the over expression of miRNAs accompanies the development of radio-resistant cancer cells. Consequently, miRNAs might serve as therapeutic targets for the treatment of radio-resistance in cancer cells. The findings of the current research also signify that the use of a natural anti-miRNA substance could inhibit specific miRNAs, and, concurrently, these natural remedies could exhibit radioprotective activity against the healthy cells during radiotherapy. Therefore, in this review, we have reported the association of miRNAs with radio-resistance and the potential uses of natural remedies as green gene therapeutic approaches, as well as radioprotectors against the adverse effects of irradiation on healthy cells during radiotherapy.

  2. Internet-Based Approaches to Building Stakeholder Networks for Conservation and Natural Resource Management

    EPA Science Inventory

    Social network analysis (SNA) is based on a conceptual network representation of social interactions and is an invaluable tool for conservation professionals to increase collaboration, improve information flow, and increase efficiency. We present two approaches to constructing i...

  3. Internet-Based Approaches to Building Stakeholder Networks for Conservation and Natural Resource Management.

    EPA Science Inventory

    Social network analysis (SNA) is based on a conceptual network representation of social interactions and is an invaluable tool for conservation professionals to increase collaboration, improve information flow, and increase efficiency. We present two approaches to constructing in...

  4. Internet-Based Approaches to Building Stakeholder Networks for Conservation and Natural Resource Management

    EPA Science Inventory

    Social network analysis (SNA) is based on a conceptual network representation of social interactions and is an invaluable tool for conservation professionals to increase collaboration, improve information flow, and increase efficiency. We present two approaches to constructing i...

  5. Internet-Based Approaches to Building Stakeholder Networks for Conservation and Natural Resource Management.

    EPA Science Inventory

    Social network analysis (SNA) is based on a conceptual network representation of social interactions and is an invaluable tool for conservation professionals to increase collaboration, improve information flow, and increase efficiency. We present two approaches to constructing in...

  6. Mimicking nature: a novel peptide-based bio-inspired approach for solar energy conversion.

    PubMed

    Gatto, Emanuela; Quatela, Alessia; Caruso, Mario; Tagliaferro, Roberto; De Zotti, Marta; Formaggio, Fernando; Toniolo, Claudio; Di Carlo, Aldo; Venanzi, Mariano

    2014-01-13

    A bioinspired approach is applied to photoelectric conversion devices. A 3(10)-helical hexapeptide bearing a pyrene unit is immobilized on a gold-covered TiO2 surface. The device is integrated for the first time in a dye-sensitized solar cell, exhibiting stability after several measurements. The approach could have promising applications in the field of optoelectronics. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. The Natural Approach to Adult Learning and Teaching of L2 Grammar

    ERIC Educational Resources Information Center

    Scheffler, Pawel

    2008-01-01

    Learning a language in a natural way is normally understood to involve the development of implicit knowledge of that language. The acquisition of such knowledge takes place through communication and is driven by learner-internal mechanisms which cannot be directly influenced by formal instruction. In the case of foreign or second language (L2)…

  8. Nature of Science Instruction to Turkish Prospective Chemistry Teachers: The Effect of Explicit-Reflective Approach

    ERIC Educational Resources Information Center

    Aglarci, Oya; Sariçayir, Hakan; Sahin, Musa

    2016-01-01

    The purpose of this study is to investigate the effect of explicit-reflective nature of science (NOS) instruction on Turkish prospective chemistry teachers' (PCTs) views of NOS. In the research, case study as a qualitative design was used and PCTs' views were examined thoroughly. The participants of the study consisted of 22 senior PCTs. Data…

  9. Natural resources interpretation: the role of researchers a new-old approach

    Treesearch

    Mark Gleason

    2002-01-01

    For the past several years interpretive programs for visitors at Isle Royale National Park have included presentations by natural resources researchers. These researchers are presenting the findings of their Lake Superior and Isle Royale National Park research directly to the public. This cooperative and developing project involves many individuals representing many...

  10. Beyond Exemplars and Prototypes as Memory Representations of Natural Concepts: A Clustering Approach

    ERIC Educational Resources Information Center

    Verbeemen, Timothy; Vanpaemel, Wolf; Pattyn, Sven; Storms, Gert; Verguts, Tom

    2007-01-01

    Categorization in well-known natural concepts is studied using a special version of the Varying Abstraction Framework (Vanpaemel, W., & Storms, G. (2006). A varying abstraction framework for categorization. Manuscript submitted for publication; Vanpaemel, W., Storms, G., & Ons, B. (2005). A varying abstraction model for categorization. In B. Bara,…

  11. A view to the future of natural gas and electricity: An integrated modeling approach

    SciTech Connect

    Cole, Wesley J.; Medlock, Kenneth B.; Jani, Aditya

    2016-03-17

    This paper demonstrates the value of integrating two highly spatially resolved models: the Rice World Gas Trade Model (RWGTM) of the natural gas sector and the Regional Energy Deployment System (ReEDS) model of the U.S. electricity sector. The RWGTM passes electricity-sector natural gas prices to the ReEDS model, while the ReEDS model returns electricity-sector natural gas demand to the RWGTM. The two models successfully converge to a solution under reference scenario conditions. We present electricity-sector and natural gas sector evolution using the integrated models for this reference scenario. This paper demonstrates that the integrated models produced similar national-level results as when running in a stand-alone form, but that regional and state-level results can vary considerably. As we highlight, these regional differences have potentially significant implications for electric sector planners especially in the wake of substantive policy changes for the sector (e.g., the Clean Power Plan).

  12. The FRAME Project - A collaborative modeling approach to natural resource management at Mesa Verde National Park

    Treesearch

    Christine E. Turner; William H. Romme; Jim Chew; Mark E. Miller; Lisa Floyd-Hanna Leavesley; George San Miguel; Neil Cobb; Richard Zirbes; Roland Viger; Kirsten Ironside

    2008-01-01

    The rapid pace of social and environmental changes over the past few decades has presented significant challenges for the people who manage our public lands. Demographic shifts have placed large populations in close proximity to public lands and have resulted in increased public scrutiny of decision making on those lands. Natural resource managers are required to make...

  13. An optimization approach to selecting research natural areas in National Forests

    Treesearch

    Stephanie A. Snyder; Lucy E. Tyrrell; Robert G. Haight

    1999-01-01

    The USDA Forest Service has a long-established program to identify areas in national forests for designation as protected Research Natural Areas (RNAs). One of the goals is to protect high quality examples of regional ecosystems for the purposes of maintaining biological diversity, conducting nonmanipulative research and monitoring, and fostering education. When RNA...

  14. Teaching Science Rhetorically: An Interdisciplinary Approach to Natural History, 1948-1985.

    ERIC Educational Resources Information Center

    DePaolo, Charles

    1987-01-01

    Considers the different analogies used by James Rettie, Teilhard de Chardin, Robert Ardrey, Jacob Bronowski, Richard Leakey, Steven Weinberg, Heinz Pagels, and Carl Sagan to make concepts related to time and natural history accessible to the layperson. Suggests that these analogies be used at the undergraduate level in both humanities and science…

  15. An Approach for Evaluating the Progress of Natural Attenuation in Groundwater (Web Conference)

    EPA Science Inventory

    Monitored Natural Attenuation (MNA) is widely applied to ground water contamination at hazardous waste sites. Under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), MNA is considered to be a remedy like any other remedy. When MNA has been select...

  16. Polymer Selection Approach for Commonly and Uncommonly Used Natural Fibers Under Uncertainty Environments

    NASA Astrophysics Data System (ADS)

    AL-Oqla, Faris M.; Sapuan, S. M.

    2015-07-01

    Factors like awareness of the scarcity of non-renewable natural resources, high petroleum prices, and demands for environmental sustainability, as well as reducing the amount of environmental pollution, have led to a renewed interest in natural fiber reinforced polymer composites as a potential bio-based material type. The best polymer matrix type in view of the wide range of conflicting criteria to form a polymeric-based composite material suitable for sustainable industry under an uncertainty environment has still not been sufficiently determined. This work introduces a selection model to evaluate the available polymers for natural fibers to enhance the industrial sustainability theme. The model built was developed to evaluate various polymer types and to determine their relative merits taking account of various conflicting criteria for both commonly used and uncommonly used natural fibers utilizing the analytical hierarchy process technique. It was found that the choice of the best polymer type for a certain fiber type depends strongly on the polymers' intrinsic desirable conflicting characteristics. Polymers evaluations are illustrated for different technical criteria in order to facilitate the polymer selection process for various industrial applications with high confidence levels.

  17. Children's Concepts of Natural Phenomena: Use of a Cognitive Mapping Approach to Describe These Concepts.

    ERIC Educational Resources Information Center

    Rowell, Richard M.

    Reported is a study based on the summary findings of a series of studies which indicated that many children who receive organized instruction designed around the few major concepts of science do, in fact, use scientific models to explain their observations of natural phenomena. The instruction that children in the study received was delivered by…

  18. High School Biology Students' Transfer of the Concept of Natural Selection: A Mixed-Methods Approach

    ERIC Educational Resources Information Center

    Pugh, Kevin J.; Koskey, Kristin L. K.; Linnenbrink-Garcia, Lisa

    2014-01-01

    The concept of natural selection serves as a foundation for understanding diverse biological concepts and has broad applicability to other domains. However, we know little about students' abilities to transfer (i.e. apply to a new context or use generatively) this concept and the relation between students' conceptual understanding and transfer…

  19. High-pressure Diels-Alder approach to natural kainic acid.

    PubMed

    Pandey, Sushil K; Orellana, Arturo; Greene, Andrew E; Poisson, Jean-François

    2006-11-23

    The first Diels-Alder based synthesis of (-)-kainic acid is described. Danishefsky's diene and a vinylogous malonate derived from 4-hydroxyproline combine under high pressure to afford a key bicyclic intermediate with virtually no loss of enantiopurity. This adduct can be converted into the natural product with complete stereocontrol. [reaction: see text].

  20. Beyond Exemplars and Prototypes as Memory Representations of Natural Concepts: A Clustering Approach

    ERIC Educational Resources Information Center

    Verbeemen, Timothy; Vanpaemel, Wolf; Pattyn, Sven; Storms, Gert; Verguts, Tom

    2007-01-01

    Categorization in well-known natural concepts is studied using a special version of the Varying Abstraction Framework (Vanpaemel, W., & Storms, G. (2006). A varying abstraction framework for categorization. Manuscript submitted for publication; Vanpaemel, W., Storms, G., & Ons, B. (2005). A varying abstraction model for categorization. In B. Bara,…

  1. Effects of sediment transport on survival of salmonid embryos in a natural stream: A simulation approach

    Treesearch

    Thomas E. Lisle; Jack Lewis

    1992-01-01

    A model is presented that simulates the effects of streamflow and sediment transport on survival of salmonid embryos incubating in spawning gravels in a natural channel. Components of the model include a 6-yr streamflow record, an empirical bed load-transport function, a relation between transport and infiltration of sandy bedload into a gravel bed, effects of fine-...

  2. The Natural Approach to Adult Learning and Teaching of L2 Grammar

    ERIC Educational Resources Information Center

    Scheffler, Pawel

    2008-01-01

    Learning a language in a natural way is normally understood to involve the development of implicit knowledge of that language. The acquisition of such knowledge takes place through communication and is driven by learner-internal mechanisms which cannot be directly influenced by formal instruction. In the case of foreign or second language (L2)…

  3. A view to the future of natural gas and electricity: An integrated modeling approach

    DOE PAGES

    Cole, Wesley J.; Medlock, Kenneth B.; Jani, Aditya

    2016-03-17

    This paper demonstrates the value of integrating two highly spatially resolved models: the Rice World Gas Trade Model (RWGTM) of the natural gas sector and the Regional Energy Deployment System (ReEDS) model of the U.S. electricity sector. The RWGTM passes electricity-sector natural gas prices to the ReEDS model, while the ReEDS model returns electricity-sector natural gas demand to the RWGTM. The two models successfully converge to a solution under reference scenario conditions. We present electricity-sector and natural gas sector evolution using the integrated models for this reference scenario. This paper demonstrates that the integrated models produced similar national-level results asmore » when running in a stand-alone form, but that regional and state-level results can vary considerably. As we highlight, these regional differences have potentially significant implications for electric sector planners especially in the wake of substantive policy changes for the sector (e.g., the Clean Power Plan).« less

  4. Undergraduate Students' Conceptions of Natural and Anthropogenic Climate Change: A Case Study Approach

    ERIC Educational Resources Information Center

    Trenbath, Thien-Kim Leckie

    2012-01-01

    This dissertation shows the evolution of five undergraduate students' ideas of natural and anthropogenic climate change throughout a lecture hall course on climate change. This research was informed by conceptual change theory and students' inaccurate ideas of climate change. Subjects represented different levels of climate change understanding at…

  5. High School Biology Students' Transfer of the Concept of Natural Selection: A Mixed-Methods Approach

    ERIC Educational Resources Information Center

    Pugh, Kevin J.; Koskey, Kristin L. K.; Linnenbrink-Garcia, Lisa

    2014-01-01

    The concept of natural selection serves as a foundation for understanding diverse biological concepts and has broad applicability to other domains. However, we know little about students' abilities to transfer (i.e. apply to a new context or use generatively) this concept and the relation between students' conceptual understanding and transfer…

  6. Molecular approaches to the investigation of viable dinoflagellate cysts in natural sediments from estuarine environments.

    PubMed

    Coyne, Kathryn J; Craig Cary, S

    2005-01-01

    Molecular methods offer an efficient alternative to microscopic identification of dinoflagellate cysts in natural sediments. Unfortunately, amplification of DNA also detects the presence of dead cells and is not a reliable indication of cyst viability. Because mRNA transcripts are more labile than DNA, the presence of specific transcripts may be used as a proxy for cyst viability. Here, we evaluate mRNA detection capabilities for identification of viable cysts of the dinoflagellate, Pfiesteria piscicida, in natural sediment samples. We targeted transcripts for cytochrome c oxidase subunit 1, cytochrome b (COB), and Tags 343 and 277, recently identified by serial analysis of gene expression. Expression was confirmed in laboratory cultures and compared with natural sediment samples. Three of the transcripts were detected in sediments by RT-PCR. The fourth transcript, for COB, was not detected in sediments, perhaps because of down-regulation of the gene in anoxic conditions. Our results suggest that methods targeting specific mRNA transcripts may be useful for detection of viable cysts in natural sediment samples. In addition, dinoflagellate cysts, which sustain extended periods of anoxia, may provide an important source of data for studies of anoxia tolerance by microbial eukaryotes.

  7. Teaching Science Rhetorically: An Interdisciplinary Approach to Natural History, 1948-1985.

    ERIC Educational Resources Information Center

    DePaolo, Charles

    1987-01-01

    Considers the different analogies used by James Rettie, Teilhard de Chardin, Robert Ardrey, Jacob Bronowski, Richard Leakey, Steven Weinberg, Heinz Pagels, and Carl Sagan to make concepts related to time and natural history accessible to the layperson. Suggests that these analogies be used at the undergraduate level in both humanities and science…

  8. Undergraduate Students' Conceptions of Natural and Anthropogenic Climate Change: A Case Study Approach

    ERIC Educational Resources Information Center

    Trenbath, Thien-Kim Leckie

    2012-01-01

    This dissertation shows the evolution of five undergraduate students' ideas of natural and anthropogenic climate change throughout a lecture hall course on climate change. This research was informed by conceptual change theory and students' inaccurate ideas of climate change. Subjects represented different levels of climate change understanding at…

  9. An Approach for Evaluating the Progress of Natural Attenuation in Groundwater (Web Conference)

    EPA Science Inventory

    Monitored Natural Attenuation (MNA) is widely applied to ground water contamination at hazardous waste sites. Under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), MNA is considered to be a remedy like any other remedy. When MNA has been select...

  10. Science Teachers' Thinking about the Nature of Science: A New Methodological Approach to Its Assessment

    ERIC Educational Resources Information Center

    Vazquez-Alonso, Angel; Garcia-Carmona, Antonio; Manassero-Mas, Maria Antonia; Bennassar-Roig, Antoni

    2013-01-01

    This paper describes Spanish science teachers' thinking about issues concerning the nature of science (NOS) and the relationships connecting science, technology, and society (STS). The sample consisted of 774 in-service and pre-service teachers. The participants responded to a selection of items from the Questionnaire of Opinions on Science,…

  11. Longitudinal, Educational Design Research Investigation of the Temporal Nature of Learning: Taking a Vygotskian Approach

    ERIC Educational Resources Information Center

    Cook, John

    2010-01-01

    The nature of learning is being augmented by new digital tools, particularly by mobile devices and the networks and structures to which they connect people. In this paper I examine some longitudinal research "threads" that have pervaded my work over the last two decades: (i) the powerful perspectives on learning and development put…

  12. Long-term assessment of natural attenuation: statistical approach on soils with aged PAH contamination.

    PubMed

    Ouvrard, Stéphanie; Chenot, Elodie-Denise; Masfaraud, Jean-François; Schwartz, Christophe

    2013-07-01

    Natural attenuation processes valorization for PAH-contaminated soil remediation has gained increasing interest from site owners. A misunderstanding of this method and a small amount of data available does not encourage its development. However, monitored natural attenuation (MNA) offers a valuable, cheaper and environmentally friendly alternative to more classical options such as physico-chemical treatments (e.g., chemical oxidation, thermal desorption). The present work proposes the results obtained during a long-term natural attenuation assessment of historically contaminated industrial soils under real climatic conditions. This study was performed after a 10 year natural attenuation period on 60 off-ground lysimeters filled with contaminated soils from different former industrial sites (coking industry, manufactured gas plants) whose initial concentration of PAH varied between 380 and 2,077 mg kg(-1). The analysed parameters included leached water characterization, soil PAH concentrations, evaluation of vegetation cover quality and quantity. Results showed a good efficiency of the PAH dissipation and limited transfer of contaminants to the environment. It also highlighted the importance of the fine soil fractions in controlling PAH reactivity. PAH dissipation through water leaching was limited and did not present a significant risk for the environment. This PAH water concentration appeared however as a good indicator of overall dissipation rate, thereby illustrating the importance of pollutant availability in predicting its degradation potential.

  13. A library screening approach identifies naturally occurring RNA sequences for a G-quadruplex binding ligand.

    PubMed

    Mirihana Arachchilage, Gayan; Morris, Mark J; Basu, Soumitra

    2014-02-07

    An RNA G-quadruplex library was synthesised and screened against kanamycin A as the ligand. Naturally occurring G-quadruplex forming sequences that differentially bind to kanamycin A were identified and characterized. This provides a simple and effective strategy for identification of potential intracellular G-quadruplex targets for a ligand.

  14. Undergraduate students' conceptions of natural and anthropogenic climate change: A case study approach

    NASA Astrophysics Data System (ADS)

    Trenbath, Thien-Kim Leckie

    This dissertation shows the evolution of five undergraduate students' ideas of natural and anthropogenic climate change throughout a lecture hall course on climate change. This research was informed by conceptual change theory and students' inaccurate ideas of climate change. Subjects represented different levels of climate change understanding at the beginning of the course and were selected based on their scores on a climate change questionnaire. The study was designed to research how students' ideas changed throughout the course and compare trajectories of lower and higher achieving students. At the beginning, students had different levels of understanding, but as the semester continued, the lower-performing students progressed more than the higher-performing students. At the end of the course, all students described more ideas than they did at the beginning; however some of these ideas were inconsistent with the professors' instruction. Lower-performing students struggled more than the higher-performing students. Struggles included differentiating climate change and its causes, effects, and consequences from other environmental problems. Students also struggled with the idea that climate change is anthropogenic despite it being natural in the past. In order to understand that climate change is impacted by human forcings in addition to natural forcings, students developed the relationship that climate change is natural and humans are "speeding it up." They took time to integrate this relationship into their prior ideas. Three of the students constructed a definition of climate change that was different than the professor's. Two students defined "climate change" as only the natural aspects of climate change and reserved the anthropogenic changes for the term "global warming". For a third student, "climate change" included damming rivers, eutrophication, frog mutations, ozone depletion, and overfishing, which are environmental ailments but not climate change.

  15. Distribution of uranium, thorium and some stable trace and toxic elements in human hair and nails in Niška Banja Town, a high natural background radiation area of Serbia (Balkan Region, South-East Europe).

    PubMed

    Sahoo, S K; Žunić, Z S; Kritsananuwat, R; Zagrodzki, P; Bossew, P; Veselinovic, N; Mishra, S; Yonehara, H; Tokonami, S

    2015-07-01

    Human hair and nails can be considered as bio-indicators of the public exposure to certain natural radionuclides and other toxic metals over a long period of months or even years. The level of elements in hair and nails usually reflect their levels in other tissues of body. Niška Banja, a spa town located in southern Serbia, with locally high natural background radiation was selected for the study. To assess public exposure to the trace elements, hair and nail samples were collected and analyzed. The concentrations of uranium, thorium and some trace and toxic elements (Mn, Ni, Cu, Sr, Cd, and Cs) were determined using inductively coupled plasma mass spectrometry (ICP-MS). U and Th concentrations in hair varied from 0.0002 to 0.0771 μg/g and from 0.0002 to 0.0276 μg/g, respectively. The concentrations in nails varied from 0.0025 to 0.0447 μg/g and from 0.0023 to 0.0564 μg/g for U and Th, respectively. We found significant correlations between some elements in hair and nails. Also indications of spatial clustering of high values could be found. However, this phenomenon as well as the large variations in concentrations of heavy metals in hair and nail could not be explained. As hypotheses, we propose possible exposure pathways which may explain the findings, but the current data does not allow testing them.

  16. Determining public policy and resource allocation priorities for mitigating natural hazards: a capabilities-based approach.

    PubMed

    Murphy, Colleen; Gardoni, Paolo

    2007-12-01

    This paper proposes a Capabilities-based Approach to guide hazard mitigation efforts. First, a discussion is provided of the criteria that should be met by an adequate framework for formulating public policy and allocating resources. This paper shows why a common decision-aiding tool, Cost-benefit Analysis, fails to fulfill such criteria. A Capabilities-based Approach to hazard mitigation is then presented, drawing on the framework originally developed in the context of development economics and policy. The focus of a Capabilities-based Approach is protecting and promoting the well-being of individuals. Capabilities are dimensions of well-being and specified in terms of functionings. Functionings capture the various things of value an individual does or becomes in his or her life, including being alive, being healthy, and being sheltered. Capabilities refer to the real achievability of specific functionings. In the context of hazard mitigation, from a Capabilities-based Approach, decision- and policy-makers should consider the acceptability and tolerability of risks along with the affectability of hazards when determining policy formulation and resource allocation. Finally, the paper shows how the proposed approach satisfies the required criteria, and overcomes the limitations of Cost-benefit Analysis, while maintaining its strengths.

  17. Multivariate approach to quantitative analysis of Aphis gossypii Glover (Hemiptera: Aphididae) and their natural enemy populations at different cotton spacings

    NASA Astrophysics Data System (ADS)

    Malaquias, José B.; Ramalho, Francisco S.; Dos S. Dias, Carlos T.; Brugger, Bruno P.; S. Lira, Aline Cristina; Wilcken, Carlos F.; Pachú, Jéssica K. S.; Zanuncio, José C.

    2017-02-01

    The relationship between pests and natural enemies using multivariate analysis on cotton in different spacing has not been documented yet. Using multivariate approaches is possible to optimize strategies to control Aphis gossypii at different crop spacings because the possibility of a better use of the aphid sampling strategies as well as the conservation and release of its natural enemies. The aims of the study were (i) to characterize the temporal abundance data of aphids and its natural enemies using principal components, (ii) to analyze the degree of correlation between the insects and between groups of variables (pests and natural enemies), (iii) to identify the main natural enemies responsible for regulating A. gossypii populations, and (iv) to investigate the similarities in arthropod occurrence patterns at different spacings of cotton crops over two seasons. High correlations in the occurrence of Scymnus rubicundus with aphids are shown through principal component analysis and through the important role the species plays in canonical correlation analysis. Clustering the presence of apterous aphids matches the pattern verified for Chrysoperla externa at the three different spacings between rows. Our results indicate that S. rubicundus is the main candidate to regulate the aphid populations in all spacings studied.

  18. Multivariate approach to quantitative analysis of Aphis gossypii Glover (Hemiptera: Aphididae) and their natural enemy populations at different cotton spacings

    PubMed Central

    Malaquias, José B.; Ramalho, Francisco S.; dos S. Dias, Carlos T.; Brugger, Bruno P.; S. Lira, Aline Cristina; Wilcken, Carlos F.; Pachú, Jéssica K. S.; Zanuncio, José C.

    2017-01-01

    The relationship between pests and natural enemies using multivariate analysis on cotton in different spacing has not been documented yet. Using multivariate approaches is possible to optimize strategies to control Aphis gossypii at different crop spacings because the possibility of a better use of the aphid sampling strategies as well as the conservation and release of its natural enemies. The aims of the study were (i) to characterize the temporal abundance data of aphids and its natural enemies using principal components, (ii) to analyze the degree of correlation between the insects and between groups of variables (pests and natural enemies), (iii) to identify the main natural enemies responsible for regulating A. gossypii populations, and (iv) to investigate the similarities in arthropod occurrence patterns at different spacings of cotton crops over two seasons. High correlations in the occurrence of Scymnus rubicundus with aphids are shown through principal component analysis and through the important role the species plays in canonical correlation analysis. Clustering the presence of apterous aphids matches the pattern verified for Chrysoperla externa at the three different spacings between rows. Our results indicate that S. rubicundus is the main candidate to regulate the aphid populations in all spacings studied. PMID:28181503

  19. Multivariate approach to quantitative analysis of Aphis gossypii Glover (Hemiptera: Aphididae) and their natural enemy populations at different cotton spacings.

    PubMed

    Malaquias, José B; Ramalho, Francisco S; Dos S Dias, Carlos T; Brugger, Bruno P; S Lira, Aline Cristina; Wilcken, Carlos F; Pachú, Jéssica K S; Zanuncio, José C

    2017-02-09

    The relationship between pests and natural enemies using multivariate analysis on cotton in different spacing has not been documented yet. Using multivariate approaches is possible to optimize strategies to control Aphis gossypii at different crop spacings because the possibility of a better use of the aphid sampling strategies as well as the conservation and release of its natural enemies. The aims of the study were (i) to characterize the temporal abundance data of aphids and its natural enemies using principal components, (ii) to analyze the degree of correlation between the insects and between groups of variables (pests and natural enemies), (iii) to identify the main natural enemies responsible for regulating A. gossypii populations, and (iv) to investigate the similarities in arthropod occurrence patterns at different spacings of cotton crops over two seasons. High correlations in the occurrence of Scymnus rubicundus with aphids are shown through principal component analysis and through the important role the species plays in canonical correlation analysis. Clustering the presence of apterous aphids matches the pattern verified for Chrysoperla externa at the three different spacings between rows. Our results indicate that S. rubicundus is the main candidate to regulate the aphid populations in all spacings studied.

  20. Nature/nurture: reflections on approaches to the study of homosexuality.

    PubMed

    Ruse, M

    1984-01-01

    There is understandable apprehension by many people towards claims that biology plays a significant role in the etiology of homosexuality. These worries should not be allowed to deter any such work on sexual orientation. It is argued that the only proper way to evaluate biological analyses is against the full background of Darwinian evolutionary theory. Moral issues pertaining to biological research on homosexuality are addressed. Finally, it is urged that both biological and environmental factors be considered in rendering a true picture of homosexuality.

  1. Integrated approaches to natural resources management in practice: the catalyzing role of National Adaptation Programmes for Action.

    PubMed

    Stucki, Virpi; Smith, Mark

    2011-06-01

    The relationship of forests in water quantity and quality has been debated during the past years. At the same time, focus on climate change has increased interest in ecosystem restoration as a means for adaptation. Climate change might become one of the key drivers pushing integrated approaches for natural resources management into practice. The National Adaptation Programme of Action (NAPA) is an initiative agreed under the UN Framework Convention on Climate Change. An analysis was done to find out how widely ecosystem restoration and integrated approaches have been incorporated into NAPA priority adaptation projects. The data show that that the NAPAs can be seen as potentially important channel for operationalizing various integrated concepts. Key challenge is to implement the NAPA projects. The amount needed to implement the NAPA projects aiming at ecosystem restoration using integrated approaches presents only 0.7% of the money pledged in Copenhagen for climate change adaptation.

  2. Nonlocal Nature of the Viscous Transport in Supercooled Liquids: Complex Fluid Approach to Supercooled Liquids

    SciTech Connect

    Furukawa, Akira; Tanaka, Hajime

    2009-09-25

    Using molecular dynamics simulations, we show clear evidence for the nonlocal mesoscopic nature of the anomalous viscous transport in a supercooled liquid and its direct link to dynamic heterogeneity: (i) a distinct crossover from the microscopic to macroscopic viscosity at a mesoscopic length scale, which is comparable to the correlation length of dynamic heterogeneity and grows with an increase in the degree of supercooling; (ii) a strong anisotropic decay of the shear-stress autocorrelation at a finite wave number, which indicates intrinsic decoupling between the longitudinal and transverse dynamics. Our findings suggest the fundamental importance of the growing dynamic correlation in anomalous transport and shed new light on the nature of slow dynamics.

  3. Simple green approach to reinforce natural rubber with bacterial cellulose nanofibers.

    PubMed

    Trovatti, Eliane; Carvalho, Antonio J F; Ribeiro, Sidney J L; Gandini, Alessandro

    2013-08-12

    Natural rubber (NR) is a renewable polymer with a wide range of applications, which is constantly tailored, further increasing its utilizations. The tensile strength is one of its most important properties susceptible of being enhanced by the simple incorporation of nanofibers. The preparation and characterization of natural-rubber based nanocomposites reinforced with bacterial cellulose (BC) and bacterial cellulose coated with polystyrene (BCPS), yielded high performance materials. The nanocomposites were prepared by a simple and green process, and characterized by tensile tests, dynamical mechanical analysis (DMA), scanning electron microscopy (SEM), and swelling experiments. The effect of the nanofiber content on morphology, static, and dynamic mechanical properties was also investigated. The results showed an increase in the mechanical properties, such as Young's modulus and tensile strength, even with modest nanofiber loadings.

  4. Natural polyphenols down-regulate universal stress protein in Mycobacterium tuberculosis: An in-silico approach

    PubMed Central

    Aanandhi, M. Vijey; Bhattacherjee, Debojit; George, P. Samuel Gideon; Ray, Anirban

    2014-01-01

    Universal stress protein (USP) is a novel target to overcome the tuberculosis resistance. Our present study enlightens the possibilities of some natural polyphenols as an antioxidant for USP. The study has shown some molecular simulations of some selected natural antioxidants with USP. We have considered USP (Rv1636) strain for homology modeling and the selected template was taken for the docking study. Curcumin, catechin, reservetrol has shown ARG 136 (1.8Å) hydrogen bonding and two ionic bonding with carboxyl group of curcumin with LEU 130 (3.3Å) and ASN 144 (3.4Å) respectively. INH was taken for the standard molecule to perform molecular simulation. It showed poor binding interaction with the target, that is, −5.18 kcal, and two hydrogen bonding with SER 140 (1.887Å), ARG 147 (2.064Å) respectively. The study indicates possible new generation curcumin analogue for future therapy to down-regulate USP. PMID:25364695

  5. Enantioselective Syntheses of Heteroyohimbine Natural Products: A Unified Approach through Cooperative Catalysis.

    PubMed

    Younai, Ashkaan; Zeng, Bi-Shun; Meltzer, Herbert Y; Scheidt, Karl A

    2015-06-01

    Alstonine and serpentine are pentacyclic indoloquinolizidine alkaloids (referred to as "anhydronium bases") containing three contiguous stereocenters. Each possesses interesting biological activity, with alstonine being the major component of a plant-based remedy to treat psychosis and other nervous system disorders. This work describes the enantioselective total syntheses of these natural products with a cooperative hydrogen bonding/enamine-catalyzed Michael addition as the key step. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Technical approaches of a natural dye extracted from Phytolacca americana L.-berries with chemical mordants.

    PubMed

    Park, Su-Youn; Jung, Suk-Yul

    2014-01-01

    Phytolacca americana L. is a large semi-succulent herbaceous plant which reaches three meters in height. It is native to eastern North America, the Midwest, and the Gulf Coast, with more scattered populations in the far West. It is imported into Korea and has been frequently used as a traditional natural drug for diseases such as systemic edema and nephritis. Its berries, that is, fruits are shiny dark purple held in racemous clusters on pink pedicels with a pink peduncle. They are round with a flat indented top and bottom. Immature berries are green, maturing into white and then blackish purple. It is not well known how the berries are used for a natural staining yet. In this study, using Phytolacca americana L.-berries, a natural staining was analyzed. Moreover, due to the broad use of chemical mordants, five different mordants including copper acetate, aluminum potassium sulfate, sodium tartrate plus citric acid, Iron II sulfate and potassium dichromate were combined. Extracted dye from the berries stained silk fabrics with ivory. The original purple color from the berries disappeared and transformed into ivory. Although the silk fabrics were differentially stained by the berries that were combined with mordants of aluminum potassium sulfate, sodium tartrate plus citric acid and potassium dichromate, only differences in lightness and darkness were observed. Interestingly, the combination of the dye from the berries with a mordant of copper acetate and Iron II sulfate induced the staining of the silk fabrics into khaki and dark khaki, respectively. This study is the first systemic report on staining silk fabrics with Phytolacca americana L.-berries and chemical mordants and suggests application of natural products to the fiber industry.

  7. A Novel Approach to Constrain the Escape Fraction and Dust Content at High Redshift Using the Cosmic Infrared Background Fractional Anisotropy

    NASA Astrophysics Data System (ADS)

    Fernandez, Elizabeth R.; Dole, Herve; Iliev, Ilian T.

    2013-02-01

    The Cosmic Infrared Background (CIB) provides an opportunity to constrain many properties of the high-redshift (z > 6) stellar population as a whole. This background, specifically from 1 to 200 μm, should contain information about the era of reionization and the stars that are responsible for these ionizing photons. In this paper, we look at the fractional anisotropy (δI/I) of this high-redshift population, where δI is the ratio of the magnitude of the fluctuations and I is the mean intensity. We show that this can be used to constrain the escape fraction of the population as a whole, because the magnitude of the fluctuations of the CIB depends on the escape fraction, while the mean intensity does not. This results in lower values of the escape fraction producing higher values of the fractional anisotropy. This difference is predicted to be larger at longer wavelength bands (above 10 μm), albeit it is also much harder to observe in that range. We show that the fractional anisotropy can also be used to separate a dusty from a dust-free population. Finally, we discuss the constraints provided by current observations on the CIB fractional anisotropy.

  8. Identification of natural allosteric inhibitor for Akt1 protein through computational approaches and in vitro evaluation.

    PubMed

    Pragna Lakshmi, T; Kumar, Amit; Vijaykumar, Veena; Natarajan, Sakthivel; Krishna, Ramadas

    2017-03-01

    Akt, a serine/threonine protein kinase, is often hyper activated in breast and prostate cancers, but with poor prognosis. Allosteric inhibitors regulate aberrant kinase activity by stabilizing the protein in inactive conformation. Several natural compounds have been reported as inhibitors for kinases. In this study, to identify potential natural allosteric inhibitor for Akt1, we generated a seven-point pharmacophore model and screened it through natural compound library. Quercetin-7-O-β-d-glucopyranoside or Q7G was found to be the best among selected molecules based on its hydrogen bond occupancy with key allosteric residues, persistent polar contacts and salt bridges that stabilize Akt1 in inactive conformation and minimum binding free energy during molecular dynamics simulation. Q7G induced dose-dependent inhibition of breast cancer cells (MDA MB-231) and arrested them in G1 and sub-G phase. This was associated with down-regulation of anti-apoptotic protein Bcl-2, up-regulation of cleaved caspase-3 and PARP. Expression of p-Akt (Ser473) was also down-regulated which might be due to Akt1 inhibition in inactive conformation. We further confirmed the Akt1 and Q7G interaction which was observed to have a dissociation constant (Kd) of 0.246μM. With these computational, biological and thermodynamic studies, we suggest Q7G as a lead molecule and propose for its further optimization.

  9. Generalized approach to inverse problems in tomography: Image reconstruction for spatially variant systems using natural pixels

    SciTech Connect

    Baker, J.R.; Budinger, T.F.; Huesman, R.H.

    1992-10-01

    A major limitation in tomographic inverse problems is inadequate computation speed, which frequently impedes the application of engineering ideas and principles in medical science more than in the physical and engineering sciences. Medical problems are computationally taxing because a minimum description of the system often involves 5 dimensions (3 space, 1 energy, 1 time), with the range of each space coordinate requiring up to 512 samples. The computational tasks for this problem can be simply expressed by posing the problem as one in which the tomograph system response function is spatially invariant, and the noise is additive and Gaussian. Under these assumptions, a number of reconstruction methods have been implemented with generally satisfactory results for general medical imaging purposes. However, if the system response function of the tomograph is assumed more realistically to be spatially variant and the noise to be Poisson, the computational problem becomes much more difficult. Some of the algorithms being studied to compensate for position dependent resolution and statistical fluctuations in the data acquisition process, when expressed in canonical form, are not practical for clinical applications because the number of computations necessary exceeds the capabilities of high performance computer systems currently available. Reconstruction methods based on natural pixels, specifically orthonormal natural pixels, preserve symmetries in the data acquisition process. Fast implementations of orthonormal natural pixel algorithms can achieve orders of magnitude speedup relative to general implementations. Thus, specialized thought in algorithm development can lead to more significant increases in performance than can be achieved through hardware improvements alone.

  10. Modeling aesthetics to support an ecosystem services approach for natural resource management decision making.

    PubMed

    Booth, Pieter N; Law, Sheryl A; Ma, Jane; Buonagurio, John; Boyd, James; Turnley, Jessica

    2017-09-01

    This paper reviews literature on aesthetics and describes the development of vista and landscape aesthetics models. Spatially explicit variables were chosen to represent physical characteristics of natural landscapes that are important to aesthetic preferences. A vista aesthetics model evaluates the aesthetics of natural landscapes viewed from distances of more than 1000 m, and a landscape aesthetics model evaluates the aesthetic value of wetlands and forests within 1000 m from the viewer. Each of the model variables is quantified using spatially explicit metrics on a pixel-specific basis within EcoAIM™, a geographic information system (GIS)-based ecosystem services (ES) decision analysis support tool. Pixel values are "binned" into ranked categories, and weights are assigned to select variables to represent stakeholder preferences. The final aesthetic score is the weighted sum of all variables and is assigned ranked values from 1 to 10. Ranked aesthetic values are displayed on maps by patch type and integrated within EcoAIM. The response of the aesthetic scoring in the models was tested by comparing current conditions in a discrete area of the facility with a Development scenario in the same area. The Development scenario consisted of two 6-story buildings and a trail replacing natural areas. The results of the vista aesthetic model indicate that the viewshed area variable had the greatest effect on the aesthetics overall score. Results from the landscape aesthetics model indicate a 10% increase in overall aesthetics value, attributed to the increase in landscape diversity. The models are sensitive to the weights assigned to certain variables by the user, and these weights should be set to reflect regional landscape characteristics as well as stakeholder preferences. This demonstration project shows that natural landscape aesthetics can be evaluated as part of a nonmonetary assessment of ES, and a scenario-building exercise provides end users with a tradeoff

  11. The Natural Selection: Identifying Student Misconceptions through an Inquiry-Based, Critical Approach to Evolution

    ERIC Educational Resources Information Center

    Robbins, Jennifer R.; Roy, Pamela

    2007-01-01

    We invited 141 non-science major undergraduates to share and then challenge their preconceptions about evolution in a four-lesson inquiry lab unit that integrated diverse topics with rigorous assessment. Our experience suggests that an inquiring approach to evolutionary theory can be highly persuasive.

  12. Emulating natural disturbance regimes: an emerging approach for sustainable forest management

    Treesearch

    M. North; W Keeton

    2008-01-01

    Sustainable forest management integrates ecological, social, and economic objectives. To achieve the former, researchers and practitioners are modifying silvicultural practices based on concepts from successional and landscape ecology to provide a broader array of ecosystem functions than is associated with conventional approaches. One...

  13. Integrative approaches to investigating human-natural systems: the Baltimore ecosystem study

    Treesearch

    Mary L. Cadenasso; Steward T.A. Pickett; Morgan J. Grove; Morgan J. Grove

    2006-01-01

    This paper presents an overview of the research approaches used to study metropolitan Baltimore (Maryland, USA) as an ecological system. The urban ecosystem is a complex of biophysical, social, and built components, and is studied by an interdisciplinary teamof biological, social, and physical scientists, and urban designers. Ecology ?of? themetropolis is addressed...

  14. An Approach to Teaching General Chemistry II that Highlights the Interdisciplinary Nature of Science

    ERIC Educational Resources Information Center

    Sumter, Takita Felder; Owens, Patrick M.

    2011-01-01

    The need for a revised curriculum within the life sciences has been well-established. One strategy to improve student preparation in the life sciences is to redesign introductory courses like biology, chemistry, and physics so that they better reflect their disciplinary interdependence. We describe a medically relevant, context-based approach to…

  15. An Approach to Teaching General Chemistry II that Highlights the Interdisciplinary Nature of Science

    ERIC Educational Resources Information Center

    Sumter, Takita Felder; Owens, Patrick M.

    2011-01-01

    The need for a revised curriculum within the life sciences has been well-established. One strategy to improve student preparation in the life sciences is to redesign introductory courses like biology, chemistry, and physics so that they better reflect their disciplinary interdependence. We describe a medically relevant, context-based approach to…

  16. A macrocyclic approach to tetracycline natural products. Investigation of transannular alkylations and Michael additions.

    PubMed

    Wzorek, Joseph S; Knöpfel, Thomas F; Sapountzis, Ioannis; Evans, David A

    2012-12-07

    A new approach to the tetracycline core structure is presented. The pivotal intermediate is identified as macrocycle III. The two interior bonds (C4a-C12a and C5a-C11a) are to be constructed through sequential transannular Michael additions (III-II) and compression-promoted transannular isoxazole alkylations from intermediate II.

  17. A Phenomenographic Approach to Developing Academics' Understanding of the Nature of Teaching and Learning

    ERIC Educational Resources Information Center

    Akerlind, Gerlese S.

    2008-01-01

    Phenomenography is best known as an empirical research approach for investigating variation in conceptions of different educational phenomena--including learning, teaching and particular disciplinary concepts such as price in economics and motion in physics. It is less well-known for its theoretical basis, in terms of its epistemological and…

  18. Forest-Farming: An Ecological Approach to Increase Nature's Food Productivity

    ERIC Educational Resources Information Center

    Douglas, James Sholto

    1973-01-01

    An innovative approach to raise the standards of nourishment and feed tomorrow's larger population is presented, along with a short history of forest-farming, including diagrams representing orthodoxy and innovation in farming and forestry. A bold and imaginative effort employing science and technology is imperative. (EB)

  19. An Empirical-Experimental Approach to the Nature and Remediation of Conduct Disorders of Children.

    ERIC Educational Resources Information Center

    Quay, Herbert C.

    This conference paper stresses that children's behavior disorders can be modified in the classroom if they are considered as a constellation of specific behaviors rather than as deviant personality traits or disease entities. To do so, however, the children must be approached within the framework of an empirically-based classification system. A…

  20. A new approach to evaluate natural zeolite ability to sorb lead (Pb) from aqueous solutions

    NASA Astrophysics Data System (ADS)

    Drosos, Evangelos I. P.; Karapanagioti, Hrissi K.

    2013-04-01

    Lead (Pb) is a hazardous pollutant commonly found in aquatic ecosystems. Among several methods available, the addition of sorbent amendments to soils or sediments is attractive, since its application is relatively simple, while it can also be cost effective when a low cost and re-usable sorbent is used; e.g. natural zeolites. Zeolites are crystalline aluminosilicates with a three-dimensional structure composed of a set of cavities occupied by large ions and water molecules. Zeolites can accommodate a wide variety of cations, such as Na+, K+, Ca2+, Mg2+, which are rather loosely held and can readily be exchanged for others in an aqueous solution. Natural zeolites are capable of removing cations, such as lead, from aqueous solutions by ion exchange. There is a wide variation in the cation exchange capacity (CEC) of natural zeolites because of the different nature of various zeolites cage structures, natural structural defects, adsorbed ions, and their associated gangue minerals. Naturally occurring zeolites are rarely pure and are contaminated to varying degrees by other minerals, such as clays and feldspars, metals, quartz, or other zeolites as well. These impurities affect the CEC even for samples originated from the same region but from a different source. CEC of the material increases with decreasing impurity content. Potentially exchangeable ions in such impurities do not necessarily participate in ion exchange mechanism, while, in some cases, impurities may additionally block the access to active sites. For zeoliferous rocks having the same percentage of a zeolitic phase, the CEC increases with decreasing Si/Al ratio, as the more Si ions are substituted by Al ions, the more negative the valence of the matrix becomes. Sodium seems to be the most effective exchangeable ion for lead. On the contrary, it is unlikely that the potassium content of the zeolite would be substituted. A pretreatment with high concentration solutions of Na, such as 2 M NaCl, can

  1. Field survey of Canadian background soils: Implications for a new mathematical gas chromatography-flame ionization detection approach for resolving false detections of petroleum hydrocarbons in clean soils.

    PubMed

    Kelly-Hooper, Francine; Farwell, Andrea J; Pike, Glenna; Kennedy, Jocelyn; Wang, Zhendi; Grunsky, Eric C; Dixon, D George

    2014-08-01

    The reference method for the Canada-wide standard (CWS) for petroleum hydrocarbons (PHCs) in soil provides laboratories with methods for generating accurate and reproducible soil analysis results. The CWS PHC tier 1 generic soil-quality guidelines apply to 4 carbon ranges/fractions: F1 (C6-C10), F2 (C10-C16), F3 (C16-C34), and F4 (>C34). The methods and guidelines were developed and validated for soils with approximately 5% total organic carbon (TOC). However, organic soils have much higher TOC levels because of biogenic organic compounds (BOCs) originating from sources such as plant waxes and fatty acids. Coextracted BOCs can have elevated F2-F4 concentrations, which can cause false exceedances of PHC soil guidelines. The present study evaluated false PHC detections in soil samples collected from 34 background sites. The list of analytes included soil type, TOC, polycyclic aromatic hydrocarbons (PAHs), F2, F3, F4, F3a (C16-C22), and F3b (C22-C34). Soils with 3% to 41% TOC falsely exceeded the CWS PHC 300 mg/kg F3 coarse soil guideline. It was previously demonstrated that clean peat had F2:F3b ratios of less than 0.10, while crude oil spiked peat and spiked sand had higher ratios of greater than 0.10. In the present background study, all of the clean organic soils with at least 300 mg/kg F3 had F2:F3b ratios of less than 0.10, which indicated false guideline exceedances. Clean inorganic soils had low F3 concentrations, resulting in high F2:F3b ratios of greater than 0.10. Validation field studies are required to determine if the F2:F3b 0.10 PHC presence versus absence threshold value is applicable to crude oil- and diesel-contaminated sites. © 2014 SETAC.

  2. Assessment of three approaches of bioremediation (Natural Attenuation, Landfarming and Bioagumentation - Assistited Landfarming) for a petroleum hydrocarbons contaminated soil.

    PubMed

    Guarino, C; Spada, V; Sciarrillo, R

    2017-03-01

    Contamination with total petroleum hydrocarbons (TPH) subsequent to refining activities, is currently one of the major environmental problems. Among the biological remediation approaches, landfarming and in situ bioremediation strategies are of great interest. Purpose of this study was to verify the feasibility of a remediation process wholly based on biological degradation applied to contaminated soils from a decommissioned refinery. This study evaluated through a pot experiment three bioremediation strategies: a) Natural Attenuation (NA), b) Landfarming (L), c) Bioaugmentation-assisted Landfarming (LB) for the treatment of a contaminated soil with petroleum hydrocarbons (TPHs). After a 90-days trial, Bioagumentation - assistited Landfarming approach produced the best results and the greatest evident effect was shown with the most polluted samples reaching a reduction of about 86% of total petroleum hydrocarbons (TPH), followed by Landfarming (70%), and Natural Attenuation (57%). The results of this study demonstrated that the combined use of bioremediation strategies was the most advantageous option for the treatment of contaminated soil with petroleum hydrocarbons, as compared to natural attenuation, bioaugmentation or landfarming applied alone. Besides, our results indicate that incubation with an autochthonous bacterial consortium may be a promising method for bioremediation of TPH-contaminated soils. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Using epidemiological registry data to provide background rates as context for adverse events in a rheumatoid arthritis drug development program: a coordinated approach.

    PubMed

    Nyberg, Fredrik; Askling, Johan; Berglind, Niklas; Franzén, Stefan; Ho, Meilien; Holmqvist, Marie; Horne, Laura; Lampl, Kathy; Michaud, Kaleb; Pappas, Dimitrios A; Reed, George; Symmons, Deborah; Tanaka, Eiichi; Tran, Trung N; Verstappen, Suzanne M M; Wesby-van Swaay, Eveline; Yamanaka, Hisashi; Greenberg, Jeffrey D

    2015-11-01

    Observational studies can provide context for adverse events observed in clinical trials, especially for infrequent events or long-term risks. We developed methods to improve safety contextualization for a rheumatoid arthritis drug development program through coordinated analyses of multiple registries. We identified and characterized differences and similarities across five registries (Swedish Rheumatology Quality of Care Register, Consortium of Rheumatology Researchers of North America [CORRONA], Norfolk Arthritis Register, Institute of Rheumatology Rheumatoid Arthritis, and the new CORRONA International), harmonized outcome definitions, and investigated whether restricted subcohorts improved comparability with trial populations. To address confounding, we identified risk predictors for outcomes of interest (mortality, cardiovascular disease, infection, and malignancy). We used patient-level analyses at each registry and central analysis of standardized group-level data. Despite data differences, the coordinated approach enabled consistent variable definitions for key baseline characteristics and outcomes. Selection of restricted subcohorts (e.g., using active joint count criteria) improved baseline comparability with trial patients for some rheumatoid arthritis disease activity measures, but less for other characteristics (e.g., age and comorbidity); however, such selection decreased sample size considerably. For most outcomes, age was the most important risk predictor, emphasizing the importance of age/sex standardization to address confounding. The prospective approach enabled use of recent relevant data; the distributed analysis safeguarded confidentiality of registry data. Compared with reliance on published data alone, a forward-looking coordinated approach across multiple observational data sources can improve comparability and consistency and better support sensitivity analyses and data interpretation, in contextualizing safety data from clinical trials

  4. Fluorescent diagnostics of organic pollution in natural waters: A neural network approach

    SciTech Connect

    Orlov, Y.V.; Persiantsev, I.G.; Rebrik, S.P.

    1995-12-31

    Rapid diagnosis of pollution is one of the key tasks in the field of ecological monitoring of natural and technogeneous environment. One of the promising methods of fluorescent diagnosis of organic pollution of water environment is the registration and analysis of two-dimensional Spectral Fluorescent Signatures (SFS). The neural networks - based system suggested in this paper is intended for solving the problem of detection, identification, and concentration measurement of water environmental pollution. The suggested system uses SFS as input pattern and allows one to build a rapid diagnosis system for ecological monitoring.

  5. ENHANCED ATTENUATION: A REFERENCE GUIDE ON APPROACHES TO INCREASE THE NATURAL TREATMENT CAPACITY OF A SYSTEM

    SciTech Connect

    Looney, B; Michael Heitkamp, M; Gary Wein , G; Karen Vangelas, K; Karen-M Adams, K; Tom Early; Bob Borden; David Major; W. Jody Waugh; Todd Wiedemeier; Claire H. Sink

    2006-08-10

    The objective of this document is to explore the realm of enhancements to natural attenuation processes for cVOCs and review examples that have been proposed, modeled, and implemented. We will identify lessons learned from these case studies to confirm that enhancements are technically feasible and have the potential to achieve a favorable, cost-effective contaminant mass balance. Furthermore, we hope to determine if opportunities for further improvement of the enhancements exist and suggest areas where new and innovative types of enhancements might be possible.

  6. Enhanced Attenuation: A Reference Guide On Approaches To Increase The Natural Treatment Capacity Of A System

    SciTech Connect

    Vangelas, K

    2006-01-30

    The objective of this document is to explore the realm of enhancements to natural attenuation processes for cVOCs and review examples that have been proposed, modeled, and implemented. We will identify lessons learned from these case studies to confirm that enhancements are technically feasible and have the potential to achieve a favorable, cost-effective contaminant mass balance. Furthermore, we hope to determine if opportunities for further improvement of the enhancements exist and suggest areas where new and innovative types of enhancements might be possible.

  7. The cause of complexity in nature: An analytical and computational approach

    NASA Astrophysics Data System (ADS)

    Mainzer, Klaus

    2012-09-01

    This work is going to present the cause of complexity in nature from an analytical and computational point of view. The cause of complex pattern formation is explained by the local activity of cells in complex systems which are analytically modeled by nonlinear reaction-diffusion equations in physics, chemistry, biology and brain research. There are not only rigorous analytical criteria of local activity and the edge of chaos, but also constructive procedures to visualize them by computer simulations. In technology, the question arises whether these criteria and procedures can be used to construct artificial life and artificial minds.

  8. Natural Killer T-Cell Lymphoma of the Orbit: An Evidence-Based Approach.

    PubMed

    Jiménez-Pérez, Juan C; Yoon, Michael K

    2017-01-01

    Natural killer T-cell lymphoma (NKTCL) is a rare and aggressive condition with a high mortality rate. It is most commonly seen in the nasal sinuses, generally affecting the orbit by direct extension. Primary orbital NKTCL is even more rare, with only a few published cases with occasional secondary nasal involvement. This malignancy can present as a "masquerade syndrome," delaying proper diagnosis and treatment. Biopsy is required for diagnosis, which shows specific histopathological characteristics. Radiation and chemotherapy are the mainstay of treatment. Newer chemotherapies show improved prognosis.

  9. From flamingo dance to (desirable) drug discovery: a nature-inspired approach.

    PubMed

    Sánchez-Rodríguez, Aminael; Pérez-Castillo, Yunierkis; Schürer, Stephan C; Nicolotti, Orazio; Mangiatordi, Giuseppe Felice; Borges, Fernanda; Cordeiro, M Natalia D S; Tejera, Eduardo; Medina-Franco, José L; Cruz-Monteagudo, Maykel

    2017-06-15

    The therapeutic effects of drugs are well known to result from their interaction with multiple intracellular targets. Accordingly, the pharma industry is currently moving from a reductionist approach based on a 'one-target fixation' to a holistic multitarget approach. However, many drug discovery practices are still procedural abstractions resulting from the attempt to understand and address the action of biologically active compounds while preventing adverse effects. Here, we discuss how drug discovery can benefit from the principles of evolutionary biology and report two real-life case studies. We do so by focusing on the desirability principle, and its many features and applications, such as machine learning-based multicriteria virtual screening. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Health, biodiversity, and natural resource use on the Amazon frontier: an ecosystem approach.

    PubMed

    Murray, T P; Sánchez-Choy, J

    2001-01-01

    This study aims to improve the health of rural Amazonian communities through the development and application of a participatory ecosystem approach to human health assessment. In the study area marked seasonal fluctuations dictate food availability, water quality and disease outbreak. Determining the causal linkages between ecosystem variables, resource use and health required a variety of forms of inquiry at multiple scales with local participation. Landscape spatial mapping of resource use demonstrated the diversity of the ecological resources upon which communities depend. Household surveys detailed family and individual consumption and production patterns. Anthropometric measurements, parasite loading, water quality and anemia levels were used as indicators of health status. This was complemented with an ethnographic and participatory health assessment that provided the foundation for developing community action plans addressing health issues. Discussion is focused on three attributes of an ecosystem approach; (a) methodological pluralism, (b) cross-scale interactions and (c) participatory action research.

  11. Internet-Based Approaches to Building Stakeholder Networks for Conservation and Natural Resource Management

    NASA Astrophysics Data System (ADS)

    Kreakie, B. J.; Hychka, K. C.; Belaire, J. A.; Minor, E.; Walker, H. A.

    2016-02-01

    Social network analysis (SNA) is based on a conceptual network representation of social interactions and is an invaluable tool for conservation professionals to increase collaboration, improve information flow, and increase efficiency. We present two approaches to constructing internet-based social networks, and use an existing traditional (survey-based) case study to illustrate in a familiar context the deviations in methods and results. Internet-based approaches to SNA offer a means to overcome institutional hurdles to conducting survey-based SNA, provide unique insight into an institution's web presences, allow for easy snowballing (iterative process that incorporates new nodes in the network), and afford monitoring of social networks through time. The internet-based approaches differ in link definition: hyperlink is based on links on a website that redirect to a different website and relatedness links are based on a Google's "relatedness" operator that identifies pages "similar" to a URL. All networks were initiated with the same start nodes [members of a conservation alliance for the Calumet region around Chicago ( n = 130)], but the resulting networks vary drastically from one another. Interpretation of the resulting networks is highly contingent upon how the links were defined.

  12. An objective and parsimonious approach for classifying natural flow regimes at a continental scale

    NASA Astrophysics Data System (ADS)

    Archfield, S. A.; Kennen, J.; Carlisle, D.; Wolock, D.

    2013-12-01

    Hydroecological stream classification--the process of grouping streams by similar hydrologic responses and, thereby, similar aquatic habitat--has been widely accepted and is often one of the first steps towards developing ecological flow targets. Despite its importance, the last national classification of streamgauges was completed about 20 years ago. A new classification of 1,534 streamgauges in the contiguous United States is presented using a novel and parsimonious approach to understand similarity in ecological streamflow response. This new classification approach uses seven fundamental daily streamflow statistics (FDSS) rather than winnowing down an uncorrelated subset from 200 or more ecologically relevant streamflow statistics (ERSS) commonly used in hydroecological classification studies. The results of this investigation demonstrate that the distributions of 33 tested ERSS are consistently different among the classes derived from the seven FDSS. It is further shown that classification based solely on the 33 ERSS generally does a poorer job in grouping similar streamgauges than the classification based on the seven FDSS. This new classification approach has the additional advantages of overcoming some of the subjectivity associated with the selection of the classification variables and provides a set of robust continental-scale classes of US streamgauges.

  13. Internet-Based Approaches to Building Stakeholder Networks for Conservation and Natural Resource Management.

    PubMed

    Kreakie, B J; Hychka, K C; Belaire, J A; Minor, E; Walker, H A

    2016-02-01

    Social network analysis (SNA) is based on a conceptual network representation of social interactions and is an invaluable tool for conservation professionals to increase collaboration, improve information flow, and increase efficiency. We present two approaches to constructing internet-based social networks, and use an existing traditional (survey-based) case study to illustrate in a familiar context the deviations in methods and results. Internet-based approaches to SNA offer a means to overcome institutional hurdles to conducting survey-based SNA, provide unique insight into an institution's web presences, allow for easy snowballing (iterative process that incorporates new nodes in the network), and afford monitoring of social networks through time. The internet-based approaches differ in link definition: hyperlink is based on links on a website that redirect to a different website and relatedness links are based on a Google's "relatedness" operator that identifies pages "similar" to a URL. All networks were initiated with the same start nodes [members of a conservation alliance for the Calumet region around Chicago (n = 130)], but the resulting networks vary drastically from one another. Interpretation of the resulting networks is highly contingent upon how the links were defined.

  14. An objective and parsimonious approach for classifying natural flow regimes at a continental scale

    USGS Publications Warehouse

    Archfield, Stacey A.; Kennen, Jonathan G.; Carlisle, Daren M.; Wolock, David M.

    2014-01-01

    Hydro-ecological stream classification-the process of grouping streams by similar hydrologic responses and, by extension, similar aquatic habitat-has been widely accepted and is considered by some to be one of the first steps towards developing ecological flow targets. A new classification of 1543 streamgauges in the contiguous USA is presented by use of a novel and parsimonious approach to understand similarity in ecological streamflow response. This novel classification approach uses seven fundamental daily streamflow statistics (FDSS) rather than winnowing down an uncorrelated subset from 200 or more ecologically relevant streamflow statistics (ERSS) commonly used in hydro-ecological classification studies. The results of this investigation demonstrate that the distributions of 33 tested ERSS are consistently different among the classification groups derived from the seven FDSS. It is further shown that classification based solely on the 33 ERSS generally does a poorer job in grouping similar streamgauges than the classification based on the seven FDSS. This new classification approach has the additional advantages of overcoming some of the subjectivity associated with the selection of the classification variables and provides a set of robust continental-scale classes of US streamgauges. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

  15. Fingerprinting sedimentary and soil units by their natural metal contents: a new approach to assess metal contamination.

    PubMed

    Amorosi, Alessandro; Guermandi, Marina; Marchi, Nazaria; Sammartino, Irene

    2014-12-01

    One of the major issues when assessing soil contamination by inorganic substances is reliable determination of natural metal concentrations. Through integrated sedimentological, pedological and geochemical analyses of 1414 (topsoil/subsoil) samples from 707 sampling stations in the southern Po Plain (Italy), we document that the natural distribution of five potentially toxic metals (Cr, Ni, Cu, Zn and Pb) can be spatially predicted as a function of three major factors: source-rock composition, grain size variability and degree of soil weathering. Thirteen genetic and functional soil units (GFUs), each reflecting a unique combination of these three variables, are fingerprinted by distinctive geochemical signatures. Where sediment is supplied by ultramafic (ophiolite-rich) sources, the natural contents of Cr and Ni in soils almost invariably exceed the Italian threshold limits designated for contaminated lands (150 mg/kg and 120 mg/kg, respectively), with median values around twice the maximum permissible levels (345 mg/kg for Cr and 207 mg/kg for Ni in GFU B5). The original provenance signal is commonly confounded by soil texture, with general tendency toward higher metal concentrations in the finest-grained fractions. Once reliable natural metal concentrations in soils are established, the anthropogenic contribution can be promptly assessed by calculating metal enrichments in topsoil samples. The use of combined sedimentological and pedological criteria to fingerprint GFU geochemical composition is presented here as a new approach to enhance predictability of natural metal contents, with obvious positive feedbacks for legislative purposes and environmental protection. Particularly, natural metal concentrations inferred directly from a new type of pedogeochemical map, built according to the international guideline ISO 19258, are proposed as an efficient alternative to the pre-determined threshold values for soil contamination commonly established by the national

  16. A combined telemetry - tag return approach to estimate fishing and natural mortality rates of an estuarine fish

    USGS Publications Warehouse

    Bacheler, N.M.; Buckel, J.A.; Hightower, J.E.; Paramore, L.M.; Pollock, K.H.

    2009-01-01

    A joint analysis of tag return and telemetry data should improve estimates of mortality rates for exploited fishes; however, the combined approach has thus far only been tested in terrestrial systems. We tagged subadult red drum (Sciaenops ocellatus) with conventional tags and ultrasonic transmitters over 3 years in coastal North Carolina, USA, to test the efficacy of the combined telemetry - tag return approach. There was a strong seasonal pattern to monthly fishing mortality rate (F) estimates from both conventional and telemetry tags; highest F values occurred in fall months and lowest levels occurred during winter. Although monthly F values were similar in pattern and magnitude between conventional tagging and telemetry, information on F in the combined model came primarily from conventional tags. The estimated natural mortality rate (M) in the combined model was low (estimated annual rate ?? standard error: 0.04 ?? 0.04) and was based primarily upon the telemetry approach. Using high-reward tagging, we estimated different tag reporting rates for state agency and university tagging programs. The combined telemetry - tag return approach can be an effective approach for estimating F and M as long as several key assumptions of the model are met.

  17. Natural Resource Management Schemes as Entry Points for Integrated Landscape Approaches: Evidence from Ghana and Burkina Faso.

    PubMed

    Foli, Samson; Ros-Tonen, Mirjam A F; Reed, James; Sunderland, Terry

    2017-04-20

    In recognition of the failures of sectoral approaches to overcome global challenges of biodiversity loss, climate change, food insecurity and poverty, scientific discourse on biodiversity conservation and sustainable development is shifting towards integrated landscape governance arrangements. Current landscape initiatives however very much depend on external actors and funding, raising the question of whether, and how, and under what conditions, locally embedded resource management schemes can serve as entry points for the implementation of integrated landscape approaches. This paper assesses the entry point potential for three established natural resource management schemes in West Africa that target landscape degradation with involvement of local communities: the Chantier d'Aménagement Forestier scheme encompassing forest management sites across Burkina Faso and the Modified Taungya System and community wildlife resource management initiatives in Ghana. Based on a review of the current literature, we analyze the extent to which design principles that define a landscape approach apply to these schemes. We found that the CREMA meets most of the desired criteria, but that its scale may be too limited to guarantee effective landscape governance, hence requiring upscaling. Conversely, the other two initiatives are strongly lacking in their design principles on fundamental components regarding integrated approaches, continual learning, and capacity building. Monitoring and evaluation bodies and participatory learning and negotiation platforms could enhance the schemes' alignment with integrated landscape approaches.

  18. Wintering waterbirds and recreationists in natural areas: a sociological approach to the awareness of bird disturbance.

    PubMed

    Le Corre, Nicolas; Peuziat, Ingrid; Brigand, Louis; Gélinaud, Guillaume; Meur-Férec, Catherine

    2013-10-01

    Disturbance to wintering birds by human recreational activities has become a major concern for managers of many natural areas. Few studies have examined how recreationists perceive their effects on birds, although this impacts their behavior on natural areas. We surveyed 312 users on two coastal ornithological sites in Brittany, France, to investigate their perception of the effects of human activities on wintering birds. The results show that the awareness of environmental issues and knowledge of bird disturbance depends on the socioeconomic characteristics of each user group, both between the two sites and within each site. Results also indicate that, whatever the site and the user group, the vast majority of the respondents (77.6%) believed that their own presence had no adverse effects on the local bird population. Various arguments were put forward to justify the users' own harmlessness. Objective information on recreationists' awareness of environmental issues, and particularly on their own impact on birds, is important to guide managers in their choice of the most appropriate visitor educational programs. We recommend developing global but also specific educational information for each type of user to raise awareness of their own impact on birds.

  19. Forecast of natural aquifer discharge using a data-driven, statistical approach.

    PubMed

    Boggs, Kevin G; Van Kirk, Rob; Johnson, Gary S; Fairley, Jerry P

    2014-01-01

    In the Western United States, demand for water is often out of balance with limited water supplies. This has led to extensive water rights conflict and litigation. A tool that can reliably forecast natural aquifer discharge months ahead of peak water demand could help water practitioners and managers by providing advanced knowledge of potential water-right mitigation requirements. The timing and magnitude of natural aquifer discharge from the Eastern Snake Plain Aquifer (ESPA) in southern Idaho is accurately forecast 4 months ahead of the peak water demand, which occurs annually in July. An ARIMA time-series model with exogenous predictors (ARIMAX model) was used to develop the forecast. The ARIMAX model fit to a set of training data was assessed using Akaike's information criterion to select the optimal model that forecasts aquifer discharge, given the previous year's discharge and values of the predictor variables. Model performance was assessed by application of the model to a validation subset of data. The Nash-Sutcliffe efficiency for model predictions made on the validation set was 0.57. The predictor variables used in our forecast represent the major recharge and discharge components of the ESPA water budget, including variables that reflect overall water supply and important aspects of water administration and management. Coefficients of variation on the regression coefficients for streamflow and irrigation diversions were all much less than 0.5, indicating that these variables are strong predictors. The model with the highest AIC weight included streamflow, two irrigation diversion variables, and storage.

  20. From Sequential Extraction to Transport Modeling: Monitored Natural Attenuation as a Remediation Approach for Inorganic Contaminants

    SciTech Connect

    Crapse, Kimberly P.; Serkiz, Steven M.; Pishko, Adrian L.; Kaplan, Daniel L.; Lee, Cindy M.; Schank, Anja

    2005-08-18

    To quantify metal natural attenuation processes in terms of environmental availability, sequential extraction experiments were carried out on subsurface soil samples impacted by a low pH, high sulfate, metals (Be, Ni, U, As) plume associated with the long-term operation of a coal plant at the Savannah River Site in South Carolina. Despite significant heterogeneity resulting both from natural and anthropogenic factors, sequential extraction results demonstrate that pH is a controlling factor in the prediction of the distribution of metal contaminants within the solid phases in soils at the site as well as the contaminant partitioning between the soil and the soil solution. Results for beryllium, the most mobile metal evaluated, exhibit increasing attenuation along the plume flow path which corresponds to an increasing plume pH. These laboratory- and field-scale studies provide mechanistic information regarding partitioning of metals to soils at the site (one of the major attenuation mechanisms for the metals at the field site). Subsequently, these data have been used in the definition of the contaminant source terms and contaminant transport factors in risk modeling for the site.