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Sample records for residue-residue contact-type potentials

  1. Bioinformatic prediction and in vivo validation of residue-residue interactions in human proteins

    NASA Astrophysics Data System (ADS)

    Jordan, Daniel; Davis, Erica; Katsanis, Nicholas; Sunyaev, Shamil

    2014-03-01

    Identifying residue-residue interactions in protein molecules is important for understanding both protein structure and function in the context of evolutionary dynamics and medical genetics. Such interactions can be difficult to predict using existing empirical or physical potentials, especially when residues are far from each other in sequence space. Using a multiple sequence alignment of 46 diverse vertebrate species we explore the space of allowed sequences for orthologous protein families. Amino acid changes that are known to damage protein function allow us to identify specific changes that are likely to have interacting partners. We fit the parameters of the continuous-time Markov process used in the alignment to conclude that these interactions are primarily pairwise, rather than higher order. Candidates for sites under pairwise epistasis are predicted, which can then be tested by experiment. We report the results of an initial round of in vivo experiments in a zebrafish model that verify the presence of multiple pairwise interactions predicted by our model. These experimentally validated interactions are novel, distant in sequence, and are not readily explained by known biochemical or biophysical features.

  2. Predicted residue-residue contacts can help the scoring of 3D models.

    PubMed

    Tress, Michael L; Valencia, Alfonso

    2010-06-01

    During the 7th Critical Assessment of Protein Structure Prediction (CASP7) experiment, it was suggested that the real value of predicted residue-residue contacts might lie in the scoring of 3D model structures. Here, we have carried out a detailed reassessment of the contact predictions made during the recent CASP8 experiment to determine whether predicted contacts might aid in the selection of close-to-native structures or be a useful tool for scoring 3D structural models. We used the contacts predicted by the CASP8 residue-residue contact prediction groups to select models for each target domain submitted to the experiment. We found that the information contained in the predicted residue-residue contacts would probably have helped in the selection of 3D models in the free modeling regime and over the harder comparative modeling targets. Indeed, in many cases, the models selected using just the predicted contacts had better GDT-TS scores than all but the best 3D prediction groups. Despite the well-known low accuracy of residue-residue contact predictions, it is clear that the predictive power of contacts can be useful in 3D model prediction strategies. PMID:20408174

  3. Numerical Analysis of Dynamic Effects of a Nonlinear Vibro-Impact Process for Enhancing the Reliability of Contact-Type MEMS Devices

    PubMed Central

    Ostasevicius, Vytautas; Gaidys, Rimvydas; Dauksevicius, Rolanas

    2009-01-01

    This paper reports on numerical modeling and simulation of a generalized contact-type MEMS device having large potential in various micro-sensor/actuator applications, which are currently limited because of detrimental effects of the contact bounce phenomenon that is still not fully explained and requires comprehensive treatment. The proposed 2-D finite element model encompasses cantilever microstructures operating in a vacuum and impacting on a viscoelastic support. The presented numerical analysis focuses on the first three flexural vibration modes and their influence on dynamic characteristics. Simulation results demonstrate the possibility to use higher modes and their particular points for enhancing MEMS performance and reliability through reduction of vibro-impact process duration. PMID:22303170

  4. Determination of transfer rate and nature of the residue(s) in milk from {sup 14}C-atrazine cows

    SciTech Connect

    Thalacker, F.W.; Ash, S.G.; Simoneaux, B.J.

    1996-10-01

    In order to determine the rate of transfer and the nature of the atrazine residues present in milk, lactating dairy cattle were treated with atrazine at three concentrations, 0.764 ppm, 0.0747 ppm and 0.0085 ppm (dry weight of food consumed). The concentrations were selected to bridge the gap between the concentration used for EPA metabolism studies (10 ppm) and the potential exposure level of dairy cattle to atrazine and its chlorotriazine metabolites through feed. The cattle were dosed following the morning milking for nine consecutive days with a single capsule bolus of {sup 14}C-atrazine. Milk was collected twice daily and aliquots of each milking and the individual cow`s daily pool of milk were analyzed by liquid scinitllation counting (LSC). The concentrations of {sup 14}C-residues in the milk plateaued on approximately day 3 and the mean {sup 14}C-atrazine levels in milk were 11.2 ppb, 1.13 ppb and 0.152 ppb for the high, middle and low dosed animals, respectively. The transfer of radioactive level of exposure to {sup 14}C-atrazine. The nature of the residues in milk were determined by extracting milk samples and analysis by HPLC, TLC or Aminex chromatography. Diaminchlorotriazine was the only chlorinated metabolite in the milk, constituting approximately 65% to 75% of the total radioactive residues (TRR).

  5. Nonlinear piezoelectric impedance modulation induced by a contact-type failure and its application in crack monitoring

    NASA Astrophysics Data System (ADS)

    Masuda, Arata; Aoki, Junsuke; Shinagawa, Tomohiro; Iba, Daisuke; Sone, Akira

    2011-02-01

    In this paper, a self-sensing, sensitive and baseline-free structural health monitoring methodology is developed, which aims to detect and characterize local structural failures of contact type, i.e. failures which arise along with the generation, growth and/or changes of imperfect solid-solid interfaces. The nonlinear piezoelectric impedance modulation (NPIM) method presented is based on the ideas of two existing damage detection principles; a piezoelectric impedance-based methodology and a nonlinear wave modulation spectroscopy. It uses a single piezoelectric active sensor bonded on the structural surface, which is driven by a high-frequency harmonic voltage source. When the structure including a contact-type failure is subjected to a low-frequency dynamic load, the induced structural vibration causes a fluctuation of the scattering conditions for the high-frequency elastic waves at the failure because of the contact acoustic nonlinearity (CAN). This nonlinear effect of vibro-acoustic interaction yields a significant fluctuation in the driving-point impedance in the high-frequency range, which may lead to a modulation of the coupled electromechanical impedance (or admittance) of the piezoelectric active sensor. Therefore, if the sensor is driven by a fixed amplitude high-frequency harmonic voltage source, modulation of the coupled admittance can be observed as the amplitude modulation and phase modulation of the current flowing through the sensor. A simplified modeling study leads to the definition of a damage evaluation index that assesses the intensity of the stiffness fluctuation caused by the CAN. Experiments using cracked beam specimens are conducted to show how the NPIM can be observed and to examine the performance of the proposed method.

  6. Observation of Actin Filaments in Leydig Cells with a Contact-type Soft X-ray Microscope with Laser Plasma X-ray Source

    NASA Astrophysics Data System (ADS)

    Kado, Masataka; Ishino, Masahiko; Tamotsu, Satoshi; Yasuda, Keiko; Kishimoto, Maki; Nishikino, Masaharu; Kinjo, Yasuhito; Shinohara, Kunio

    Actin filaments in Leydig cells from mouse testes have been observed with a contact-type soft x-ray microscope with laser plasma x-ray source. The Leydig cells were fixed with paraformaldehyde, stained with Phalloidin, and observed with a confocal laser microscope prior to the observation with x-ray microscope. Obtained images by both of the confocal laser microscopy and the x-ray microscopy were directly compared and revealed that not only position of actin filaments but also the shapes can be identified each other. The actin filaments in the x-ray images were clearly recognized and their structures were obtained in more detail compared to those in the confocal laser microscope images.

  7. Magmatic ore deposits in layered intrusions - Descriptive model for reef-type PGE and contact-type Cu-Ni-PGE deposits

    USGS Publications Warehouse

    Zientek, Michael L.

    2012-01-01

    Layered, ultramafic to mafic intrusions are uncommon in the geologic record, but host magmatic ore deposits containing most of the world's economic concentrations of platinum-group elements (PGE) (figs. 1 and 2). These deposits are mined primarily for their platinum, palladium, and rhodium contents (table 1). Magmatic ore deposits are derived from accumulations of crystals of metallic oxides, or immiscible sulfide, or oxide liquids that formed during the cooling and crystallization of magma, typically with mafic to ultramafic compositions. "PGE reefs" are stratabound PGE-enriched lode mineralization in mafic to ultramafic layered intrusions. The term "reef" is derived from Australian and South African literature for this style of mineralization and used to refer to (1) the rock layer that is mineralized and has distinctive texture or mineralogy (Naldrett, 2004), or (2) the PGE-enriched sulfide mineralization that occurs within the rock layer. For example, Viljoen (1999) broadly defined the Merensky Reef as "a mineralized zone within or closely associated with an unconformity surface in the ultramafic cumulate at the base of the Merensky Cyclic Unit." In this report, we will use the term PGE reef to refer to the PGE-enriched mineralization, not the host rock layer. Within a layered igneous intrusion, reef-type mineralization is laterally persistent along strike, extending for the length of the intrusion, typically tens to hundreds of kilometers. However, the mineralized interval is thin, generally centimeters to meters thick, relative to the stratigraphic thickness of layers in an intrusion that vary from hundreds to thousands of meters. PGE-enriched sulfide mineralization is also found near the contacts or margins of layered mafic to ultramafic intrusions (Iljina and Lee, 2005). This contact-type mineralization consists of disseminated to massive concentrations of iron-copper-nickel-PGE-enriched sulfide mineral concentrations in zones that can be tens to hundreds

  8. The effective potential in the scattering of a charged particle by an atom in the presence of weak screening

    NASA Astrophysics Data System (ADS)

    Au, C. K.; Baird, W. H.

    1996-09-01

    We use perturbation theory to derive an expression for the effective potential in the scattering between a charged particle and a coulombic complex (an atom) in the presence of weak screening in terms of the screening length and the atomic structure sum rules. Contact-type terms are neglected.

  9. [Vasomotor Endothelial Function in Healthy Individuals: Contact Types of Character].

    PubMed

    Kirichuk, V F; Olenko, E S; Kodochigova, A I; Barylnik, Y B; Deeva, M A; Bazhenov, V A

    2015-01-01

    We studied the vascular endothelial vasomotor function in healthy young individuals, depending on the type of character accentuation, levels of neuroticism, depression and anxiety. It is shown that the types of character accentuation effect on endothelial vasomotor function in healthy men and women. Personality characteristics of a person can be a significant risk factor for disease, the pathogenesis of which is the starting element of endothelial vasomotor dysfunction. PMID:26237954

  10. Improving residue-residue contact prediction via low-rank and sparse decomposition of residue correlation matrix.

    PubMed

    Zhang, Haicang; Gao, Yujuan; Deng, Minghua; Wang, Chao; Zhu, Jianwei; Li, Shuai Cheng; Zheng, Wei-Mou; Bu, Dongbo

    2016-03-25

    Strategies for correlation analysis in protein contact prediction often encounter two challenges, namely, the indirect coupling among residues, and the background correlations mainly caused by phylogenetic biases. While various studies have been conducted on how to disentangle indirect coupling, the removal of background correlations still remains unresolved. Here, we present an approach for removing background correlations via low-rank and sparse decomposition (LRS) of a residue correlation matrix. The correlation matrix can be constructed using either local inference strategies (e.g., mutual information, or MI) or global inference strategies (e.g., direct coupling analysis, or DCA). In our approach, a correlation matrix was decomposed into two components, i.e., a low-rank component representing background correlations, and a sparse component representing true correlations. Finally the residue contacts were inferred from the sparse component of correlation matrix. We trained our LRS-based method on the PSICOV dataset, and tested it on both GREMLIN and CASP11 datasets. Our experimental results suggested that LRS significantly improves the contact prediction precision. For example, when equipped with the LRS technique, the prediction precision of MI and mfDCA increased from 0.25 to 0.67 and from 0.58 to 0.70, respectively (Top L/10 predicted contacts, sequence separation: 5 AA, dataset: GREMLIN). In addition, our LRS technique also consistently outperforms the popular denoising technique APC (average product correction), on both local (MI_LRS: 0.67 vs MI_APC: 0.34) and global measures (mfDCA_LRS: 0.70 vs mfDCA_APC: 0.67). Interestingly, we found out that when equipped with our LRS technique, local inference strategies performed in a comparable manner to that of global inference strategies, implying that the application of LRS technique narrowed down the performance gap between local and global inference strategies. Overall, our LRS technique greatly facilitates protein contact prediction by removing background correlations. An implementation of the approach called COLORS (improving COntact prediction using LOw-Rank and Sparse matrix decomposition) is available from http://protein.ict.ac.cn/COLORS/. PMID:26920058

  11. Interatomic Potential

    SciTech Connect

    Gao, Fei

    2010-01-01

    In spite of greatly increased computer speeds, the application of ab initio methods for an atomistic simulation of materials is still limited to relatively small ensembles of atoms and, in molecular dynamics, relatively short simulation times (~5 ps). In contrast, the use of empirical or semiempirical interatomic potentials makes it possible to simulate much larger systems (~ up to a few million atoms) for much longer times (~100 ns), and thus to tackle such problems as plastic deformation, ion-solid interaction, or atomic diffusion. This chapter reviews various interatomic potentials used in large-scale computer simulations.

  12. Technology Development of the Non-contact Type oil Leaks Sensor using ASK Modulation

    NASA Astrophysics Data System (ADS)

    Sugai, Yasunori; Hara, Urumi; Inoue, Akira; Hashida, Syuukichi

    We developed a new oil leakage sensor using blue-violet excitation light modulated with amplitude shift keying (ASK). The sensor can selectively detect fluorescence from insulating oil or turbine oil without being affected by ambient light.

  13. Effects of piezoelectric potential on the transport characteristics of metal-ZnO nanowire-metal field effect transistor

    PubMed Central

    Gao, Zhiyuan; Zhou, Jun; Gu, Yudong; Fei, Peng; Hao, Yue; Bao, Gang; Wang, Zhong Lin

    2009-01-01

    We have investigated the effects of piezoelectric potential in a ZnO nanowire on the transport characteristics of the nanowire based field effect transistor through numerical calculations and experimental observations. Under different straining conditions including stretching, compressing, twisting, and their combination, a piezoelectric potential is created throughout the nanowire to modulate∕alternate the transport property of the metal-ZnO nanowire contacts, resulting in a switch between symmetric and asymmetric contacts at the two ends, or even turning an Ohmic contact type into a diode. The commonly observed natural rectifying behavior of the as-fabricated ZnO nanowire can be attributed to the strain that was unpurposely created in the nanowire during device fabrication and material handling. This work provides further evidence on piezopotential governed electronic transport and devices, e.g., piezotronics. PMID:19657403

  14. Conformational Temperature-Dependent Behavior of a Histone H2AX: A Coarse-Grained Monte Carlo Approach Via Knowledge-Based Interaction Potentials

    PubMed Central

    Fritsche, Miriam; Pandey, Ras B.; Farmer, Barry L.; Heermann, Dieter W.

    2012-01-01

    Histone proteins are not only important due to their vital role in cellular processes such as DNA compaction, replication and repair but also show intriguing structural properties that might be exploited for bioengineering purposes such as the development of nano-materials. Based on their biological and technological implications, it is interesting to investigate the structural properties of proteins as a function of temperature. In this work, we study the spatial response dynamics of the histone H2AX, consisting of 143 residues, by a coarse-grained bond fluctuating model for a broad range of normalized temperatures. A knowledge-based interaction matrix is used as input for the residue-residue Lennard-Jones potential. We find a variety of equilibrium structures including global globular configurations at low normalized temperature (), combination of segmental globules and elongated chains (), predominantly elongated chains (), as well as universal SAW conformations at high normalized temperature (). The radius of gyration of the protein exhibits a non-monotonic temperature dependence with a maximum at a characteristic temperature () where a crossover occurs from a positive (stretching at ) to negative (contraction at ) thermal response on increasing . PMID:22442661

  15. Thermal response of proteins (histone H2AX, H3.1) by a coarse-grained Monte Carlo simulation with a knowledge-based phenomenological potential

    NASA Astrophysics Data System (ADS)

    Fritsche, Miriam; Heermann, Dieter; Pandey, Ras; Farmer, Barry

    2012-02-01

    Using a coarse-grained bond fluctuating model, we investigate structure and dynamics of two histones, H2AX (143 residues) and H3.1 (136 residues) as a function of temperature (T). A knowledged based contact matrix is used as an input for a phenomenological residue-residue interaction in a generalized Lennard-Jones potential. Metropolis algorithm is used to execute stochastic movement of each residue. A number of local and global physical quantities are analyzed. Despite unique energy and mobility profiles of its residues in a specific sequence, the histone H3.1 appears to undergo a structural transformation from a random coil to a globular conformation on reducing the temperature. The radius of gyration of the histone H2AX, in contrast, exhibits a non-monotonic dependence on temperature with a maximum at a characteristic temperature (Tc) where crossover occurs from a positive (stretching below Tc) to negative (contraction above Tc) thermal response on increasing T. Multi-scale structures of the proteins are examined by a detailed analysis of their structure functions.

  16. Optimal Replication Activity of Vesicular Stomatitis Virus RNA Polymerase Requires Phosphorylation of a Residue(s) at Carboxy-Terminal Domain II of Its Accessory Subunit, Phosphoprotein P

    PubMed Central

    Hwang, Leroy N.; Englund, Nathan; Das, Tapas; Banerjee, Amiya K.; Pattnaik, Asit K.

    1999-01-01

    The phosphoprotein, P, of vesicular stomatitis virus (VSV) is a key subunit of the viral RNA-dependent RNA polymerase complex. The protein is phosphorylated at multiple sites in two different domains. We recently showed that specific serine and threonine residues within the amino-terminal acidic domain I of P protein must be phosphorylated for in vivo transcription activity, but not for replication activity, of the polymerase complex. To examine the role of phosphorylation of the carboxy-terminal domain II residues of the P protein in transcription and replication, we have used a panel of mutant P proteins in which the phosphate acceptor sites (Ser-226, Ser-227, and Ser-233) were altered to alanines either individually or in various combinations. Analyses of the mutant proteins for their ability to support replication of a VSV minigenomic RNA suggest that phosphorylation of either Ser-226 or Ser-227 is necessary for optimal replication activity of the protein. The mutant protein (P226/227) in which both of these residues were altered to alanines was only about 8% active in replication compared to the wild-type (wt) protein. Substitution of alanine for Ser-233 did not have any adverse effect on replication activity of the protein. In contrast, all the mutant proteins showed activities similar to that of the wt protein in transcription. These results indicate that phosphorylation of the carboxy-terminal domain II residues of P protein are required for optimal replication activity but not for transcription activity. Furthermore, substitution of glutamic acid residues for Ser-226 and Ser-227 resulted in a protein that was only 14% active in replication but almost fully active in transcription. Taken together, these results, along with our earlier studies, suggest that phosphorylation of residues at two different domains in the P protein regulates its activity in transcription and replication of the VSV genome. PMID:10364310

  17. Ionization potentials of seaborgium

    SciTech Connect

    Johnson, E.; Pershina, V.; Fricke, B.

    1999-10-21

    Multiconfiguration relativistic Dirac-Fock values were calculated for the first six ionization potentials of seaborgium and of the other group 6 elements. No experimental ionization potentials are available for seaborgium. Accurate experimental values are not available for all of the other ionization potentials. Ionic radii for the 4+ through 6+ ions of seaborgium are also presented. The ionization potentials and ionic radii obtained will be used to predict some physiochemical properties of seaborgium and its compounds.

  18. Electron dose distributions caused by the contact-type metallic eye shield: Studies using Monte Carlo and pencil beam algorithms.

    PubMed

    Kang, Sei-Kwon; Yoon, Jai-Woong; Hwang, Taejin; Park, Soah; Cheong, Kwang-Ho; Han, Tae Jin; Kim, Haeyoung; Lee, Me-Yeon; Kim, Kyoung Ju; Bae, Hoonsik

    2015-01-01

    A metallic contact eye shield has sometimes been used for eyelid treatment, but dose distribution has never been reported for a patient case. This study aimed to show the shield-incorporated CT-based dose distribution using the Pinnacle system and Monte Carlo (MC) calculation for 3 patient cases. For the artifact-free CT scan, an acrylic shield machined as the same size as that of the tungsten shield was used. For the MC calculation, BEAMnrc and DOSXYZnrc were used for the 6-MeV electron beam of the Varian 21EX, in which information for the tungsten, stainless steel, and aluminum material for the eye shield was used. The same plan was generated on the Pinnacle system and both were compared. The use of the acrylic shield produced clear CT images, enabling delineation of the regions of interest, and yielded CT-based dose calculation for the metallic shield. Both the MC and the Pinnacle systems showed a similar dose distribution downstream of the eye shield, reflecting the blocking effect of the metallic eye shield. The major difference between the MC and the Pinnacle results was the target eyelid dose upstream of the shield such that the Pinnacle system underestimated the dose by 19 to 28% and 11 to 18% for the maximum and the mean doses, respectively. The pattern of dose difference between the MC and the Pinnacle systems was similar to that in the previous phantom study. In conclusion, the metallic eye shield was successfully incorporated into the CT-based planning, and the accurate dose calculation requires MC simulation. PMID:25724475

  19. Electron dose distributions caused by the contact-type metallic eye shield: Studies using Monte Carlo and pencil beam algorithms

    SciTech Connect

    Kang, Sei-Kwon; Yoon, Jai-Woong; Hwang, Taejin; Park, Soah; Cheong, Kwang-Ho; Jin Han, Tae; Kim, Haeyoung; Lee, Me-Yeon; Ju Kim, Kyoung Bae, Hoonsik

    2015-10-01

    A metallic contact eye shield has sometimes been used for eyelid treatment, but dose distribution has never been reported for a patient case. This study aimed to show the shield-incorporated CT-based dose distribution using the Pinnacle system and Monte Carlo (MC) calculation for 3 patient cases. For the artifact-free CT scan, an acrylic shield machined as the same size as that of the tungsten shield was used. For the MC calculation, BEAMnrc and DOSXYZnrc were used for the 6-MeV electron beam of the Varian 21EX, in which information for the tungsten, stainless steel, and aluminum material for the eye shield was used. The same plan was generated on the Pinnacle system and both were compared. The use of the acrylic shield produced clear CT images, enabling delineation of the regions of interest, and yielded CT-based dose calculation for the metallic shield. Both the MC and the Pinnacle systems showed a similar dose distribution downstream of the eye shield, reflecting the blocking effect of the metallic eye shield. The major difference between the MC and the Pinnacle results was the target eyelid dose upstream of the shield such that the Pinnacle system underestimated the dose by 19 to 28% and 11 to 18% for the maximum and the mean doses, respectively. The pattern of dose difference between the MC and the Pinnacle systems was similar to that in the previous phantom study. In conclusion, the metallic eye shield was successfully incorporated into the CT-based planning, and the accurate dose calculation requires MC simulation.

  20. Studies on the Evaluation Methods for the Food Quality with a Non-contact type Capacitance Sensor.

    NASA Astrophysics Data System (ADS)

    Narumiya, Tadaoki; Hagura, Yoshio

    Changes of capacitance and temperature of ethyl alcohol, hamburger and dough with cheese filling were measured with specially-made measuring devices during the freezing and thawing. The results of measurement of capacitance and temperature suggest a linear correlation for ethyl alcohol as a single constituent substance. The adequate correlation is too estimated from the results of food samples, though the capacitance of food sample varies greatly at the start and end of freezing and thawing process. It has been demonstrated that the quality or physical condition of food sample can be determined easily by the measurement of capacitance using the specially-made devices. Also the quality or physical condition of food can be determined easily by the non-contact and non-destructive measurements of capacitance. A variety application of the present technique is conceivable for the process control of the freezing and thawing foods.

  1. Pixel patterns for voxels in a contact-type three-dimensional imaging system for full-parallax image display

    SciTech Connect

    Son, Jung-Young; Saveljev, Vladmir V.; Javidi, Bahram; Kim, Dae-Sik; Park, Min-Chul

    2006-06-20

    Incomplete voxels, which can be seen only at a part of the viewing zone's cross section in the optical configuration of a full parallax multiview imaging system based on a two-dimensional point light source array, are identified. Their corresponding pixel patterns are found to maximize the space where the voxels can exist in the configuration and to increase the voxel resolution of the displayable three-dimensional images. Furthermore, the pixel patterns for the rhomb-shaped pixel cells are also defined, and some problems related to voxel-based image synthesis are discussed.

  2. The effects of physical contact type on the internal and external demands during a rugby league match simulation protocol.

    PubMed

    Norris, Jonathan P; Highton, Jamie; Hughes, Stephen F; Twist, Craig

    2016-10-01

    The aim of this study was to investigate how the type of contact influences physiological, perceptual and locomotive load during a simulated rugby league match. Eleven male university rugby league players performed two trials of the rugby league movement simulation protocol for interchange forwards with a traditional soft tackle bag and a weighted tackle sled to replicate contact demands. The interchange forward-specific simulation was chosen given the contact frequency is higher for this group of players compared to whole match players. Locomotive rate, sprint speed, tackle intensity, heart rate (HR) and rating of perceived exertion were analysed during the first and second bouts that replicated two ~23 min on-field passages. Countermovement jump (CMJ) was measured before and immediately after each trial. More time was spent in heart rate zone between 91 and 100% HRpeak during the first (effect size ± 90% confidence interval: 0.44 ± 0.49) and second bouts (0.44 ± 0.43), and larger (0.6 ± 0.69) decrements in CMJ performance were observed during the sled trial (5.9, s = 4.9%) compared to the bag trial (2.6, s = 5.4%). Changing the type of contact during the match simulation subtly altered both the internal and external loads on participants. Using a standard tackle bag results in faster sprint speed to contact, but lower overall high-intensity running. Conversely, a heavier tackle object increases the internal load and results in greater lower limb neuromuscular fatigue as reflected by the decrease in CMJ performance. PMID:26860532

  3. Redox Potential of Peroxidases

    NASA Astrophysics Data System (ADS)

    Ayala, Marcela

    Redox potential of peroxidases greatly influences the range of oxidizable substrates: in principle, peroxidases may only catalyze the oxidation of substrates with lower redox potential. There is substantial information on the factors that modulate the redox potential of heme proteins. Both theoretical and experimental evidence highlight the most significant contributions arising from the interaction of heme iron with the axial ligands, as well as the electrostatic interactions surrounding the heme group. However, for different proteins, the factors contribute to different extents. Understanding the electrochemistry of heme peroxidases is fundamental in order to design enhanced biocatalysts. In this chapter, current knowledge of the forces influencing redox potential of heme peroxidases is reviewed.

  4. Pumping potential wells

    NASA Technical Reports Server (NTRS)

    Hershkowitz, N.; Forest, C.; Wang, E. Y.; Intrator, T.

    1987-01-01

    Nonmonotonic plasma potential structures are a common feature of many double layers and sheaths. Steady state plasma potential wells separating regions having different plasma potentials are often found in laboratory experiments. In order to exist, all such structures must find a solution to a common problem. Ions created by charge exchange or ionization in the region of the potential well are electrostatically confined and tend to accumulate and fill up the potential well. The increase in positive charge should eliminate the well. Nevertheless, steady state structures are found in which the wells do not fill up. This means that it is important to take into account processes which pump ions from the well. As examples of ion pumping of plasma wells, potential dips in front of a positively biased electron collecting anode in a relatively cold, low density, multidipole plasma are considered. Pumping is provided by ion leaks from the edges of the potential dip or by oscillating the applied potential. In the former case the two-dimensional character of the problem is shown to be important.

  5. Pumping potential wells

    NASA Technical Reports Server (NTRS)

    Hershkowitz, N.; Forest, C.; Wang, E. Y.; Intrator, T.

    1987-01-01

    Nonmonotonic plasma potential structures are a common feature of many double layers and sheaths. Steady state plasma potential wells separating regions having different plasma potentials are often found in laboratory experiments. In order to exist, such structures all must find a solution to a common problem. Ions created by charge exchange or ionization in the region of the potential well are electrostatically confined and tend to accumulate and fill up the potential well. The increase in positive charge should eliminate the well. Nevertheless, steady state structures are found in which the wells do not fill up. This means that it is important to take into account processes which 'pump' ions from the well. As examples of ion pumping of plasma wells, potential dips in front of a positively biased electro collecting anode in a relatively cold, low density multidipole plasma is considered. Pumping is provided by ion leaks from the edges of the potential dip or by oscillating the applied potential. In the former case the two dimensional character of the problem is shown to be important.

  6. Revisiting Curriculum Potential

    ERIC Educational Resources Information Center

    Deng, Zongyi

    2011-01-01

    This article analyzes the notion of curriculum potential by revisiting the ideas of Miriam Ben-Peretz and Joseph Schwab. Invoking the German "Didaktik" tradition and by way of a curriculum-making framework, the paper argues that interpreting curriculum materials for curriculum potential requires a careful analysis and unpacking of the meanings and…

  7. Potential conservation laws

    SciTech Connect

    Kunzinger, Michael; Popovych, Roman O.

    2008-10-15

    We prove that potential conservation laws have characteristics depending only on local variables if and only if they are induced by local conservation laws. Therefore, characteristics of pure potential conservation laws have to essentially depend on potential variables. This statement provides a significant generalization of results of the recent paper by Bluman et al. [J. Math. Phys. 47, 113505 (2006)]. Moreover, we present extensions to gauged potential systems, Abelian and general coverings, and general foliated systems of differential equations. An example illustrating possible applications of these results is given. A special version of the Hadamard lemma for fiber bundles and the notions of weighted jet spaces are proposed as new tools for the investigation of potential conservation laws.

  8. Potential theory of radiation

    NASA Technical Reports Server (NTRS)

    Chiu, Huei-Huang

    1989-01-01

    A theoretical method is being developed by which the structure of a radiation field can be predicted by a radiation potential theory, similar to a classical potential theory. The introduction of a scalar potential is justified on the grounds that the spectral intensity vector is irrotational. The vector is also solenoidal in the limits of a radiation field in complete radiative equilibrium or in a vacuum. This method provides an exact, elliptic type equation that will upgrade the accuracy and the efficiency of the current CFD programs required for the prediction of radiation and flow fields. A number of interesting results emerge from the present study. First, a steady state radiation field exhibits an optically modulated inverse square law distribution character. Secondly, the unsteady radiation field is structured with two conjugate scalar potentials. Each is governed by a Klein-Gordon equation with a frictional force and a restoring force. This steady potential field structure and the propagation of radiation potentials are consistent with the well known results of classical electromagnetic theory. The extension of the radiation potential theory for spray combustion and hypersonic flow is also recommended.

  9. Cardiac action potential imaging

    NASA Astrophysics Data System (ADS)

    Tian, Qinghai; Lipp, Peter; Kaestner, Lars

    2013-06-01

    Action potentials in cardiac myocytes have durations in the order of magnitude of 100 milliseconds. In biomedical investigations the documentation of the occurrence of action potentials is often not sufficient, but a recording of the shape of an action potential allows a functional estimation of several molecular players. Therefore a temporal resolution of around 500 images per second is compulsory. In the past such measurements have been performed with photometric approaches limiting the measurement to one cell at a time. In contrast, imaging allows reading out several cells at a time with additional spatial information. Recent developments in camera technologies allow the acquisition with the required speed and sensitivity. We performed action potential imaging on isolated adult cardiomyocytes of guinea pigs utilizing the fluorescent membrane potential sensor di-8-ANEPPS and latest electron-multiplication CCD as well as scientific CMOS cameras of several manufacturers. Furthermore, we characterized the signal to noise ratio of action potential signals of varying sets of cameras, dye concentrations and objective lenses. We ensured that di-8-ANEPPS itself did not alter action potentials by avoiding concentrations above 5 μM. Based on these results we can conclude that imaging is a reliable method to read out action potentials. Compared to conventional current-clamp experiments, this optical approach allows a much higher throughput and due to its contact free concept leaving the cell to a much higher degree undisturbed. Action potential imaging based on isolated adult cardiomyocytes can be utilized in pharmacological cardiac safety screens bearing numerous advantages over approaches based on heterologous expression of hERG channels in cell lines.

  10. Morally relevant potential.

    PubMed

    Hershenov, David B; Hershenov, Rose J

    2015-03-01

    Fetuses and infants are said to warrant protecting because of their potential. But valuing potential supposedly leads to absurdities like protecting cells that could be technologically altered to develop into persons. This can be avoided by recognising that morally relevant potential is determined by what is presently healthy development (proper functioning) for an organism. The only interests of mindless organisms are in the flourishing that necessarily depends upon their healthy functioning. They can be harmed when those interests are frustrated. We criticise McMahan for claiming that harm is instead a function of the degree of psychological ties to the future. PMID:24570396

  11. Recovering the inflationary potential

    SciTech Connect

    Turner, Michael S.

    1993-08-06

    A procedure is developed for the recovery of the inflationary potential owl the interval that affects astrophysical scales. The amplitudes of the scalar and tensor metric perturbations and their power-spectrum indices, which can in principle be inferred from large-angle CBR anisotropy experiments and other cosmological data, determine the value of the inflationary potential and its first two derivatives. From these, the inflationary potential can be reconstructed in a Taylor series and the consistency of the inflationary hypothesis tested. A number of examples are presented, and the effect of observational uncertainties is discussed.

  12. Ground potential rise monitor

    DOEpatents

    Allen, Zachery Warren; Zevenbergen, Gary Allen

    2012-07-17

    A device and method for detecting ground potential rise (GPR) comprising a first electrode, a second electrode, and a voltage attenuator. The first electrode and the second electrode are both electrically connected to the voltage attenuator. A means for determining the presence of a dangerous ground potential is connected to the voltage attenuator. The device and method further comprises a means for enabling one or more alarms upon the detection of the dangerous ground potential. Preferably, a first transmitter/receiver is connected to the means for enabling one or more alarms. Preferably, a second transmitter/receiver, comprising a button, is electromagnetically connected to the first transmitter/receiver. Preferably, the means for determining the presence of a dangerous ground potential comprises a means for determining the true RMS voltage at the output of the voltage attenuator, a transient detector connected to the output of the voltage attenuator, or a combination thereof.

  13. The preference for potential.

    PubMed

    Tormala, Zakary L; Jia, Jayson S; Norton, Michael I

    2012-10-01

    When people seek to impress others, they often do so by highlighting individual achievements. Despite the intuitive appeal of this strategy, we demonstrate that people often prefer potential rather than achievement when evaluating others. Indeed, compared with references to achievement (e.g., "this person has won an award for his work"), references to potential (e.g., "this person could win an award for his work") appear to stimulate greater interest and processing, which can translate into more favorable reactions. This tendency creates a phenomenon whereby the potential to be good at something can be preferred over actually being good at that very same thing. We document this preference for potential in laboratory and field experiments, using targets ranging from athletes to comedians to graduate school applicants and measures ranging from salary allocations to online ad clicks to admission decisions. PMID:22775472

  14. California's potential volcanic hazards

    SciTech Connect

    Jorgenson, P. )

    1989-01-01

    Although volcanic eruptions have occurred infrequently in California during the last few thousand years, the potential danger to life and property from volcanoes in the state is great enough to be of concern, according to a recent U.S. Geological Survey (USGS) publication. The 17-page bulletin, Potential Hazards from Future Volcanic Eruptions in California, gives a brief history of volcanic activity in California during the past 100,000 years, descriptions of the types of volcanoes in the state, the types of potentially hazardous volcanic events that could occur, and hazard-zonation maps and tables depicting six areas of the state where volcanic eruptions might occur. The six areas and brief descriptions of their past volcanic history and potential for future volcanic hazards are briefly summarized here.

  15. Elderberry: Botany, Horticulture, Potential

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Horticultural Review allows extensive reviews of the state of the knowledge on certain topics or crops. Elderberry: Botany, Horticulture, Potential, is outlined with an Introduction, Botany, Horticulture, Propagation, Uses and Conclusion sections. This review compiles literature from around the w...

  16. Constant potential pulse polarography

    USGS Publications Warehouse

    Christie, J.H.; Jackson, L.L.; Osteryoung, R.A.

    1976-01-01

    The new technique of constant potential pulse polarography, In which all pulses are to be the same potential, is presented theoretically and evaluated experimentally. The response obtained is in the form of a faradaic current wave superimposed on a constant capacitative component. Results obtained with a computer-controlled system exhibit a capillary response current similar to that observed In normal pulse polarography. Calibration curves for Pb obtained using a modified commercial pulse polarographic instrument are in good accord with theoretical predictions.

  17. Estimating earthquake potential

    USGS Publications Warehouse

    Page, R.A.

    1980-01-01

    The hazards to life and property from earthquakes can be minimized in three ways. First, structures can be designed and built to resist the effects of earthquakes. Second, the location of structures and human activities can be chosen to avoid or to limit the use of areas known to be subject to serious earthquake hazards. Third, preparations for an earthquake in response to a prediction or warning can reduce the loss of life and damage to property as well as promote a rapid recovery from the disaster. The success of the first two strategies, earthquake engineering and land use planning, depends on being able to reliably estimate the earthquake potential. The key considerations in defining the potential of a region are the location, size, and character of future earthquakes and frequency of their occurrence. Both historic seismicity of the region and the geologic record are considered in evaluating earthquake potential

  18. Ancestry, Temporality, and Potentiality

    PubMed Central

    Gibbon, Sahra

    2014-01-01

    In this paper I examine the variety of ways potential is articulated, entailed, and produced in how the field of cancer genetics is being constituted as a domain of transnational research and an emerging site of health-care intervention in southern Brazil. Drawing on analysis of fieldwork in Brazilian cancer-genetics clinics, I explore how different expressions of potential come to inform dynamically the pursuit of prevention, care, and research as diversely scaled investments for those working and living with cancer-genetics knowledge and technologies. It illustrates how specific temporalities help to constitute and “abductively” frame the meaning of these different potentials particularly as this relates to a focus on ancestry. Colonial histories of migration, the embodied effects of dietary habits, or the moral failings of near and distant ancestors as well as promissory futures and the contingency of lived lives become at different times templates for identifying, materializing, and transforming how the potential of cancer genetics in Brazil is articulated. Potential is also expressed through an idiom of “choice” in different efforts to situate participation in cancer-genetics research as prevention or to negotiate access to basic public health. I explore how these expressions of cancer genetics as potential powerfully yet unevenly work to sustain knowledge practices as well as propel patients and their families into fledgling domains of clinical practice and scientific research. At the same time there is always an “excess of meaning” in these endeavors that make visible lines of fracture and disjuncture in collective efforts to make future histories of and from the pursuit of cancer genetics in southern Brazil. PMID:25018561

  19. Costs and Potential Economies.

    ERIC Educational Resources Information Center

    Bottomley, J. A.; And Others

    The University of Bradford was designated as the target for research directed toward identifying potential economies in the teaching of students under alternative sets of assumptions, in order that action may be taken to secure a more economic use of resources in the higher education sector. Part one looks generally at the nature of university…

  20. Realizing Their Potential.

    ERIC Educational Resources Information Center

    Orloff, Jeffrey H., Ed.

    The report contains the proceedings of the Third Annual Northern Virginia Conference on Gifted/Talented Education. Titles and authors of papers presented include "Realizing Your Potential" (H. Lyon), "Developing the Gifts of All Children" (W. Barbe), "What is Leadership Training for the Gifted?" (D. Sisk), "Theoretic Foundations of Differential…

  1. The Human Potential Movement.

    ERIC Educational Resources Information Center

    Tamashiro, Roy T.

    The advent of the human potential movement has generated the expectation that educators unleash the intellectual, emotional, physical, and spiritual talents of students. This movement is characterized by its focus on (1) the person as a total being, (2) the needs and concerns of students, (3) phenomenology, (4) personal values and goals, and (5)…

  2. Measurement of Electric Potentials

    ERIC Educational Resources Information Center

    Tait, A.

    1973-01-01

    Describes the measurement of electric potentials by means of a flame probe. This method is used extensively in the new Nuffield Advanced Level Physics course, and provides a means of taking reliable quantitative results in an area of most school courses where the majority of the work is qualitative. (JR)

  3. SOMATOSENSORY EVOKED POTENTIALS

    EPA Science Inventory

    Somatosensory evoked potentials (SEPs) have been used by neuroscientists for many years. The versatility of the method is attested to be the differing purposes to which it has been applied. Initially, SEPs were used to uncover basic principles of sensory processing. A casual glan...

  4. Five Potential Crises.

    ERIC Educational Resources Information Center

    Futurist, 1984

    1984-01-01

    Five areas that have great potential for becoming crises in the future are described: a warming of the earth's climate, changing weather patterns and growing seasons; water shortage; the decay of the physical infrastructure, e.g., decay of roads, bridges; breakdown of the international monetary and trading system; and nuclear warfare. (Author/RM)

  5. Forecasting Potential Crises.

    ERIC Educational Resources Information Center

    Neufeld, William P.

    1984-01-01

    By foreseeing the possibility of crisis, we can plan how to respond. Five potential crisis areas are identified and possible consequences discussed. The areas are the warming of the earth; water shortage; collapse of the physical infrastructure, e.g., decay of roads; global financial crisis; and the threat of nuclear war. (Author/RM)

  6. Exploration potential of Albania

    SciTech Connect

    Silverman, M.R. )

    1991-08-01

    Albania is rich in natural resources, especially crude oil and natural gas. It has far greater petroleum reserves for its size than any other country in Eastern Europe. The nation consists of three principal geologic provinces. Strongly folded upper Paleozoic and Mesozoic strata comprise the Sub-Pelagonian and Pelagonian massifs in the northeast Albania. The search for oil and gas in the future is likely to be concentrated in the coastal basins and offshore in the relatively shallow waters of the Adriatic Sea. Hydrocarbons have been trapped onshore in anticlines and tilted fault blocks, primarily in lenticular upper Miocene sandstones and in Helvetian limestones. Exploration for stratigraphic and other nonstructural traps may represent the best potential for future discoveries onshore. Albania's greatest oil and gas potential is probably in the Albanian shelf of the Durres basin, offshore. No wells have ever been drilled offshore, and exploration is confined to a limited, nearshore seismic survey. Recent access to Albanian data suggests most published regional interpretations are many years out of date. Albania's offshore potential includes several zones of hydrocarbon generation in Mesozoic to Paleogene strata. Potential reservoirs include Neogene flysch sandstones and Mesozoic platform carbonates. Albania has recently invited foreign oil companies to apply for offshore exploration rights. As Albania is opened to foreign investment in the petroleum sector, there is little doubt that modern seismic techniques and the deliberate search for subtle traps may be expected to lead to substantial new discoveries.

  7. Graphing Electric Potential.

    ERIC Educational Resources Information Center

    De Jong, Marvin L.

    1993-01-01

    Describes the powerful graphing ability of computer algebra systems (CAS) to create three-dimensional graphs or surface graphics of electric potentials. Provides equations along with examples of the printouts. Lists the programs Mathematica, Maple, Derive, Theorist, MathCad, and MATLAB as promising CAS systems. (MVL)

  8. POTENTIAL NATURAL VEGETATION COVERAGE

    EPA Science Inventory

    "Potential natural vegetation is defined as the vegetation that would exist today if humans were removed from the scene and if the plant succession after their removal were telescoped into a single moment. The time compression eliminates the effects of future climatic fluc...

  9. Nonadiabatic Ponderomotive Potentials

    SciTech Connect

    Dodin IY, Fisch NJ

    2005-10-03

    An approximate integral of the Manley-Rowe type is found for a particle moving in a high-frequency field, which may interact resonantly with natural particle oscillations. An effective ponderomotive potential is introduced accordingly and can capture nonadiabatic particle dynamics. We show that nonadiabatic ponderomotive barriers can trap classical particles, produce cooling effect, and generate one-way walls for resonant species. Possible atomic applications are also envisioned.

  10. Restraining potentially violent patients.

    PubMed

    Splawn, G

    1991-10-01

    People who are emotionally distraught or mentally ill are rarely predictable. A calm, reassuring, but firm and decisive manner is most effective in dealing with out-of-control patients. Staff members should be careful to never position themselves with a potentially violent or distraught patient between them and the door. A room should be emptied of all extraneous, potentially dangerous objects before restraint of a patient. A clear plan of what is to be done and who is to do what is necessary. All staff members should remove glasses, pens, scissors, and other items that are potential weapons before restraining a patient. A humane attitude when restraining patients is extremely important. Sometimes the attitude of those applying restraints can be more traumatic than the actual application of the restraints. It is important that staff members remember that patients who need restraint are not "bad" people. For whatever reason, they have lost the ability to control themselves. These people do not like being out of control; given a choice, they would choose not to be. The staff attitude during this stressful event, which is becoming all too common in the emergency department, can have a tremendous effect on patients who require this procedure. When a patient is restrained in a competent, humane manner, staff members can pride themselves on their skills in dealing successfully with this emergency, just as they can when dealing with a cardiac arrest. Finally, it has been said that you cannot truly understand what another person is going through until you have had the same experience yourself.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1921070

  11. Potentialities of silicon photomultiplier

    NASA Astrophysics Data System (ADS)

    Pagano, R.; Libertino, S.; Corso, D.; Valvo, G.; Sanfilippo, D.; Fallica, P. G.; Lombardo, S.

    2014-03-01

    The Silicon Photomultiplier (SiPM) is a novel pixelated photon detector able to detect single photon arrival with good timing resolution and high gain. In this work we present a complete study of the performances of different SiPMs produced by STMicroelectronics. Their potentialities and limits were identified using experimental measurements and electrical simulations performed both on single pixel and SiPM having up to ˜4000 pixels. SiPM was tested in different experiments such as photoluminescence emission measurement, lifetime measurement of semiconductor materials and light diffusion in highly scattering material in the near infrared spectrum showing its aptitude to replace PMT in those applications.

  12. On quantum potential dynamics

    NASA Astrophysics Data System (ADS)

    Goldstein, Sheldon; Struyve, Ward

    2015-01-01

    Non-relativistic de Broglie-Bohm theory describes particles moving under the guidance of the wave function. In de Broglie's original formulation, the particle dynamics is given by a first-order differential equation. In Bohm's reformulation, it is given by Newton's law of motion with an extra potential that depends on the wave function—the quantum potential—together with a constraint on the possible velocities. It was recently argued, mainly by numerical simulations, that relaxing this velocity constraint leads to a physically untenable theory. We provide further evidence for this by showing that for various wave functions the particles tend to escape the wave packet. In particular, we show that for a central classical potential and bound energy eigenstates the particle motion is often unbounded. This work seems particularly relevant for ways of simulating wave function evolution based on Bohm's formulation of the de Broglie-Bohm theory. Namely, the simulations may become unstable due to deviations from the velocity constraint.

  13. Potential Future Shuttle Improvements

    NASA Technical Reports Server (NTRS)

    Henderson, Edward

    2001-01-01

    NASA has just recently completed the 104th flight of the Space Shuttle. Each of the four Orbiters in the Shuttle fleet have a design life of 100 flights each. Thus the fleet is capable of almost 300 more flights, and at current flight rates could potentially operate well past 2020 if necessary. This paper addresses some of the potential Shuttle system improvements that could be considered if the decision is made to continue operations of this vehicle for such an extended period. The national space transportation policy envisions a decision around 2005-2006 concerning readiness to start development of a Shuttle replacement system. Leading up to that decision point NASA is investing in the Space Launch Initiative (SLI) to reduce the development risks associated with key technologies needed for the next generation reusable launch vehicle (RLV). The Shuttle replacement could be a new design RLV or could be based on a Shuttle derived design: i.e., a vehicle based on the current Shuttle but with major design changes. The technology investment strategy of SLI is supportive of either approach. However, if NASA and industry are not ready to develop a replacement vehicle in the 2006-2012 timeframe, then another option would be to continue to make important, but evolutionary changes, to the existing Shuttle fleet. The overall strategy for next generation RLV planning, including possible Shuttle evolution, is captured in Figure 1.

  14. Evaluation of hydrocarbon potential

    SciTech Connect

    Cashman, P.H.; Trexler, J.H. Jr.

    1992-09-30

    Task 8 is responsible for assessing the hydrocarbon potential of the Yucca Mountain vincinity. Our main focus is source rock stratigraphy in the NTS area in southern Nevada. (In addition, Trexler continues to work on a parallel study of source rock stratigraphy in the oil-producing region of east central Nevada, but this work is not funded by Task 8.) As a supplement to the stratigraphic studies, we are studying the geometry and kinematics of deformation at NTS, particularly as these pertain to reconstructing Paleozoic stratigraphy and to predicting the nature of the Late Paleozoic rocks under Yucca Mountain. Our stratigraphic studies continue to support the interpretation that rocks mapped as the {open_quotes}Eleana Formation{close_quotes} are in fact parts of two different Mississippian units. We have made significant progress in determining the basin histories of both units. These place important constraints on regional paleogeographic and tectonic reconstructions. In addition to continued work on the Eleana, we plan to look at the overlying Tippipah Limestone. Preliminary TOC and maturation data indicate that this may be another potential source rock.

  15. Industrial potential of lipoxygenases.

    PubMed

    Heshof, Ruud; de Graaff, Leo H; Villaverde, Juan J; Silvestre, Armando J D; Haarmann, Thomas; Dalsgaard, Trine K; Buchert, Johanna

    2016-08-01

    Lipoxygenases (LOXs) are iron- or manganese-containing oxidative enzymes found in plants, animals, bacteria and fungi. LOXs catalyze the oxidation of polyunsaturated fatty acids to the corresponding highly reactive hydroperoxides. Production of hydroperoxides by LOX can be exploited in different applications such as in bleaching of colored components, modification of lipids originating from different raw materials, production of lipid derived chemicals and production of aroma compounds. Most application research has been carried out using soybean LOX, but currently the use of microbial LOXs has also been reported. Development of LOX composition with high activity by heterologous expression in suitable production hosts would enable full exploitation of the potential of LOX derived reactions in different applications. Here, we review the biological role of LOXs, their heterologous production, as well as potential use in different applications. LOXs may fulfill an important role in the design of processes that are far more environmental friendly than currently used chemical reactions. Difficulties in screening for the optimal enzymes and producing LOX enzymes in sufficient amounts prevent large-scale application so far. With this review, we summarize current knowledge of LOX enzymes and the way in which they can be produced and applied. PMID:25641326

  16. Characterization of bioelectric potentials

    NASA Technical Reports Server (NTRS)

    Jorgensen, Charles C. (Inventor); Wheeler, Kevin R. (Inventor)

    2004-01-01

    Method and system for recognizing and characterizing bioelectric potential or electromyographic (EMG) signals associated with at least one of a coarse gesture and a fine gesture that is performed by a person, and use of the bioelectric potentials to enter data and/or commands into an electrical and/or mechanical instrument. As a gesture is performed, bioelectric signals that accompany the gesture are subjected to statistical averaging, within selected time intervals. Hidden Markov model analysis is applied to identify hidden, gesture-related states that are present. A metric is used to compare signals produced by a volitional gesture (not yet identified) with corresponding signals associated with each of a set of reference gestures, and the reference gesture that is closest to the volitional gesture is identified. Signals representing the volitional gesture are analyzed and compared with a database of reference gestures to determine if the volitional gesture is likely to be one of the reference gestures. Electronic and/or mechanical commands needed to carry out the gesture may be implemented at an interface to control an instrument. Applications include control of an aircraft, entry of data from a keyboard or other data entry device, and entry of data and commands in extreme environments that interfere with accurate entry.

  17. Intrinsic anion oxidation potentials.

    PubMed

    Johansson, Patrik

    2006-11-01

    Anions of lithium battery salts have been investigated by electronic structure calculations with the objective to find a computational measure to correlate with the observed (in)stability of nonaqueous lithium battery electrolytes vs oxidation often encountered in practice. Accurate prediction of intrinsic anion oxidation potentials is here made possible by computing the vertical free energy difference between anion and neutral radical (Delta Gv) and further strengthened by an empirical correction using only the anion volume as a parameter. The 6-311+G(2df,p) basis set, the VSXC functional, and the C-PCM SCRF algorithm were used. The Delta Gv calculations can be performed using any standard computational chemistry software. PMID:17078600

  18. Ground potential rise monitor

    DOEpatents

    Allen, Zachery W.; Zevenbergen, Gary A.

    2012-04-03

    A device and method for detecting ground potential rise (GPR) comprising positioning a first electrode and a second electrode at a distance from each other into the earth. The voltage of the first electrode and second electrode is attenuated by an attenuation factor creating an attenuated voltage. The true RMS voltage of the attenuated voltage is determined creating an attenuated true RMS voltage. The attenuated true RMS voltage is then multiplied by the attenuation factor creating a calculated true RMS voltage. If the calculated true RMS voltage is greater than a first predetermined voltage threshold, a first alarm is enabled at a local location. If user input is received at a remote location acknowledging the first alarm, a first alarm acknowledgment signal is transmitted. The first alarm acknowledgment signal is then received at which time the first alarm is disabled.

  19. Potential vorticity in magnetohydrodynamics

    NASA Astrophysics Data System (ADS)

    Webb, G. M.; Mace, R. L.

    2015-01-01

    A version of Noether's second theorem using Lagrange multipliers is used to investigate fluid relabelling symmetries conservation laws in magnetohydrodynamics (MHD). We obtain a new generalized potential vorticity type conservation equation for MHD which takes into account entropy gradients and the J × B force on the plasma due to the current J and magnetic induction B. This new conservation law for MHD is derived by using Noether's second theorem in conjunction with a class of fluid relabelling symmetries in which the symmetry generator for the Lagrange label transformations is non-parallel to the magnetic field induction in Lagrange label space. This is associated with an Abelian Lie pseudo algebra and a foliated phase space in Lagrange label space. It contains as a special case Ertel's theorem in ideal fluid mechanics. An independent derivation shows that the new conservation law is also valid for more general physical situations.

  20. Schwanniomyces: a potential superyeast

    SciTech Connect

    Ingledew, W.M.

    1987-01-01

    In 1977, when our quest to determine the industrial potential of the genus Schwanniomyces began, little was known about this microbe. The genus was first described by Kloecker in 1909, after the isolation in the Antilles of Schwanniomyces occidentalis. A number of biological descriptions (see Ferreira and Phaff) and other species were also described. In addition, it was known that close to 100 yeasts were able to assimilate at least part of the starch molecule. Then, Augustin et al. and Costamagna et al. reported the ability of Schwanniomyces spp. to produce extracellular alpha-amylase and utilize starch. Later discoveries would indicate that both alpha-amylase and glucoamylase were present, and from then on, research with the yeast Schwanniomyces would become very competitive - especially in Canada and Europe. (Refs. 53).

  1. Power and Biological Potential

    NASA Astrophysics Data System (ADS)

    Hoehler, T. M.; Som, S. M.; Kempes, C.; Jørgensen, B. B.

    2014-12-01

    Habitability, biomass abundance, growth rates, and rates of evolution are constrained by the availability of biologically accessible energy through time -- power. It is well understood that life requires energy not only to grow, but also to support standing biomass without new growth. Quantifying this "maintenance energy" requirement is critical for understanding the biological potential of low energy systems, including many systems of astrobiological interest, but field- and culture-based estimates differ by as much as three orders of magnitude. Here, we evaluate and compare these estimates to environmental energy supply in two examples: methanogenic metabolism in serpentinizing systems and a hypothetical "thermotrophic" metabolism. In both cases, evaluation of the power budget introduces constraint and resolution beyond that provided by evaluation of Gibbs energy change for metabolic reactions.

  2. Supersonic nonlinear potential analysis

    NASA Technical Reports Server (NTRS)

    Siclari, M. J.

    1984-01-01

    The NCOREL computer code was established to compute supersonic flow fields of wings and bodies. The method encompasses an implicit finite difference transonic relaxation method to solve the full potential equation in a spherical coordinate system. Two basic topic to broaden the applicability and usefulness of the present method which is encompassed within the computer code NCOREL for the treatment of supersonic flow problems were studied. The first topic is that of computing efficiency. Accelerated schemes are in use for transonic flow problems. One such scheme is the approximate factorization (AF) method and an AF scheme to the supersonic flow problem is developed. The second topic is the computation of wake flows. The proper modeling of wake flows is important for multicomponent configurations such as wing-body and multiple lifting surfaces where the wake of one lifting surface has a pronounced effect on a downstream body or other lifting surfaces.

  3. Corrosion potential analysis system

    NASA Astrophysics Data System (ADS)

    Kiefer, Karl F.

    1998-03-01

    Many cities in the northeastern U.S. transport electrical power from place to place via underground cables, which utilize voltages from 68 kv to 348 kv. These cables are placed in seamless steel pipe to protect the conductors. These buried pipe-type-cables (PTCs) are carefully designed and constantly pressurized with transformer oil to prevent any possible contamination. A protective coating placed on the outside diameter of the pipe during manufacture protects the steel pipe from the soil environment. Notwithstanding the protection mechanisms available, the pipes remain vulnerable to electrochemical corrosion processes. If undetected, corrosion can cause the pipes to leak transformer oil into the environment. These leaks can assume serious proportions due to the constant pressure on the inside of the pipe. A need exists for a detection system that can dynamically monitor the corrosive potential on the length of the pipe and dynamically adjust cathodic protection to counter local and global changes in the cathodic environment surrounding the pipes. The northeastern United States contains approximately 1000 miles of this pipe. This milage is critical to the transportation and distribution of power. So critical, that each of the pipe runs has a redundant double running parallel to it. Invocon, Inc. proposed and tested a technically unique and cost effective solution to detect critical corrosion potential and to communicate that information to a central data collection and analysis location. Invocon's solution utilizes the steel of the casing pipe as a communication medium. Each data gathering station on the pipe can act as a relay for information gathered elsewhere on the pipe. These stations must have 'smart' network configuration algorithms that constantly test various communication paths and determine the best and most power efficient route through which information should flow. Each network station also performs data acquisition and analysis tasks that ultimately

  4. Creative potential in schizophrenia.

    PubMed

    Buck, L A; Kramer, A

    1977-05-01

    The purpose of this paper is to demonstrate the presence of creative potential in a group of hospitalized persons who have been categorized as schizophrenic. Previous work (Buck and Kramer, 1973, 1974) has made it obvious that considerable poetic skill exists in this group of people. While creative potential was apparent in large numbers of those we have worked with, it is unnecessary to claim that our present data represent all (or even a majority) of the hospital population. However, we are concerned with providing a more balanced perspective on the ego strength and creativity which are retained in people who are labeled schizophrenic-even those considered to be regressed. In the following selections, we will attempt to demonstrate, first, an openness to fantasy and an access to primary-process thought which is molded by sufficient technical skill to warrant being labeled poetry, and second, an active, reconstructive capacity which includes a clear intention of communicating with an audience. The technical skill and the reconstructive capacity are critical in substantiating the retention of ego strength necessary for the mobilization of secondary-process cognition. We are interested, therefore, in exploring poetry written with clarity, intelligibility, and cohesiveness, where the visual can be translated into the verbal, where the effort is directed toward communication rather than sorcery, and where sponteneity replacesstereotypy. In the case of originality of style-that is, artistic license-these distinctions may not always be clear; but where questions arise, the artist's ability to justify his own intentions becomes critical. PMID:870920

  5. On potential space.

    PubMed

    Ogden, T H

    1985-01-01

    In this paper, I have proposed that Winnicott's concept of potential space might be understood as a state of mind based upon a series of dialectical relationships between fantasy and reality, me and not-me, symbol and symbolized, etc., each pole of the dialectic creating, informing, and negating the other. The achievement of such a dialectical process occurs by means of a developmental advance from the 'invisible oneness' of the mother-infant unit to the subjective 'three-ness' of the mother-and-infant (as symbolic objects) and the infant (as interpreting subject). Failure to create or maintain the dialectical process leads to specific forms of psychopathology that include the experience of the fantasy object as a thing in itself, the defensive use of reality that forecloses imagination, the relationship to a fetish object, and the state of 'non-experience'. The 'processing' of a projective identification is understood as the re-establishment of the recipient's capacity to maintain a dialectical process (e.g. of me and not-me) that had been limited in the course of the recipient's unconscious participation in the projector's externalized unconscious fantasy. PMID:2410383

  6. Ethanol fermentation and potential.

    PubMed

    Miller, D L

    1975-01-01

    Ethyl alcohol is one of the United States and world's major chemicals. Beverage alcohol in the United States must be prepared from cereal grains or other natural products. The U.S. industrial alcohol market has remained relatively stable for several years at approximately 300 million gallons annually. Most of this has been produced synthetically from petroleum raw material (gas and oil). These raw materials are experiencing major price increases and are in short supply. The production of ethyl alcohol from cereal grains and cellulosic raw materials by fermentation is technically feasible and has been proven. Alcohol produced from all such materials is equal to synthetic alcohol in quality and performance. Competitive economics have controlled the basic raw materials used. The major potential new ethyl alcohol market is as a component of automobile fuels. A 10% alcohol-gasoline blend in the United States would annually require over 10 billion gallons of anhydrous alcohol. Use of alcohol for this purpose is technically feasible. However, alcohol has not been economically competitive to date. PMID:1191746

  7. Hydrocarbon potential of Morocco

    SciTech Connect

    Achnin, H.; Nairn, A.E.M.

    1988-08-01

    Morocco lies at the junction of the African and Eurasian plates and carries a record of their movements since the end of the Precambrian. Four structural regions with basins and troughs can be identified: Saharan (Tarfaya-Ayoun and Tindouf basins); Anti-Atlas (Souss and Ouarzazate troughs and Boudnib basin); the Essaouria, Doukkala, Tadla, Missour, High Plateau, and Guercif basins; and Meseta and Rif (Rharb and Pre-Rif basins). The targets in the Tindouf basin are Paleozoic, Cambrian, Ordovician (clastics), Devonian (limestones), and Carboniferous reservoirs sourced primarily by Silurian shales. In the remaining basins, excluding the Rharb, the reservoirs are Triassic detritals, limestones at the base of the Lias and Dogger, Malm detritals, and sandy horizons in the Cretaceous. In addition to the Silurian, potential source rocks include the Carboniferous and Permo-Carboniferous shales and clays; Jurassic shales, marls, and carbonates; and Cretaceous clays. In the Rharb basin, the objectives are sand lenses within the Miocene marls. The maturation level of the organic matter generally corresponds to oil and gas. The traps are stratigraphic (lenses and reefs) and structural (horsts and folds). The seals in the pre-Jurassic rocks are shales and evaporites; in the younger rocks, shales and marl. Hydrocarbon accumulations have been found in Paleozoic, Triassic, Liassic, Malm, and Miocene rocks.

  8. Colorado Potential Geothermal Pathways

    DOE Data Explorer

    Zehner, Richard E.

    2012-02-01

    Citation Information: Originator: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Publication Date: 2012 Title: Colorado PRS Cool Fairways Edition: First Publication Information: Publication Place: Earth Science & Observation Center, Cooperative Institute for Research in Environmental Science (CIRES), University of Colorado, Boulder Publisher: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Description: This layer contains the weakened basement rocks. Isostatic gravity was utilized to identify structural basin areas, characterized by gravity low values reflecting weakened basement rocks. Together interpreted regional fault zones and basin outlines define geothermal "exploration fairways", where the potential exists for deep, superheated fluid flow in the absence of Pliocene or younger volcanic units Spatial Domain: Extent: Top: 4544698.569273 m Left: 144918.141004 m Right: 763728.391299 m Bottom: 4094070.397932 m Contact Information: Contact Organization: Earth Science &Observation Center (ESOC), CIRES, University of Colorado at Boulder Contact Person: Khalid Hussein Address: CIRES, Ekeley Building Earth Science & Observation Center (ESOC) 216 UCB City: Boulder State: CO Postal Code: 80309-0216 Country: USA Contact Telephone: 303-492-6782 Spatial Reference Information: Coordinate System: Universal Transverse Mercator (UTM) WGS’1984 Zone 13N False Easting: 500000.00000000 False Northing: 0.00000000 Central Meridian: -105.00000000 Scale Factor: 0.99960000 Latitude of Origin: 0.00000000 Linear Unit: Meter Datum: World Geodetic System ’1984 (WGS ’1984) Prime Meridian: Greenwich Angular Unit: Degree Digital Form: Format Name: Shape file

  9. Potential dangers of cannabis.

    PubMed

    Kaymakçalan, S

    1975-01-01

    Cannabis is not a harmless drug. The potential dangers of cannabis are briefly reviewed in this report. The above-mentioned observations on cannabis users should be kept in mind and carefully examined by all physicians. One could expect that as more potent cannabis preparations become available, some of the toxic manifestations which now seem rare might become more frequent. Some of the remarks about the dangers of cannabis may not be proved in future studies, and they may represent only our anxiety. However, prior to the elimination of these fears, no steps should be taken toward the legalizing of marijuana. At present there is no scientific evidence that cannabis is less harmful than either tobacco or alcohol. The opposite may be true. The analogy can be drawn between opium and cannabis. The permissive attitude toward the use of opium can easily lead to the use of morphine and other opiates. If we legalize the use of marijuana, we cannot prevent the use of more dangerous derivatives of cannabis; namely, hashish, cannabis oil and THC, itself. In my opinion, in the light of our present knowledge, legalizing of marijuana could be hazardous both for the individual and for society. PMID:1181294

  10. RANGELAND SEQUESTRATION POTENTIAL ASSESSMENT

    SciTech Connect

    Lee Spangler; George F. Vance; Gerald E. Schuman; Justin D. Derner

    2012-03-31

    Rangelands occupy approximately half of the world's land area and store greater than 10% of the terrestrial biomass carbon and up to 30% of the global soil organic carbon. Although soil carbon sequestration rates are generally low on rangelands in comparison to croplands, increases in terrestrial carbon in rangelands resulting from management can account for significant carbon sequestration given the magnitude of this land resource. Despite the significance rangelands can play in carbon sequestration, our understanding remains limited. Researchers conducted a literature review to identify sustainably management practices that conserve existing rangeland carbon pools, as well as increase or restore carbon sequestration potentials for this type of ecosystem. The research team also reviewed the impact of grazing management on rangeland carbon dynamics, which are not well understood due to heterogeneity in grassland types. The literature review on the impact of grazing showed a wide variation of results, ranging from positive to negative to no response. On further review, the intensity of grazing appears to be a major factor in controlling rangeland soil organic carbon dynamics. In 2003, researchers conducted field sampling to assess the effect of several drought years during the period 1993-2002. Results suggested that drought can significantly impact rangeland soil organic carbon (SOC) levels, and therefore, carbon sequestration. Resampling was conducted in 2006; results again suggested that climatic conditions may have overridden management effects on SOC due to the ecological lag of the severe drought of 2002. Analysis of grazing practices during this research effort suggested that there are beneficial effects of light grazing compared to heavy grazing and non-grazing with respect to increased SOC and nitrogen contents. In general, carbon storage in rangelands also increases with increased precipitation, although researchers identified threshold levels of

  11. Identifying potential academic leaders

    PubMed Central

    White, David; Krueger, Paul; Meaney, Christopher; Antao, Viola; Kim, Florence; Kwong, Jeffrey C.

    2016-01-01

    Objective To identify variables associated with willingness to undertake leadership roles among academic family medicine faculty. Design Web-based survey. Bivariate and multivariable analyses (logistic regression) were used to identify variables associated with willingness to undertake leadership roles. Setting Department of Family and Community Medicine at the University of Toronto in Ontario. Participants A total of 687 faculty members. Main outcome measures Variables related to respondents’ willingness to take on various academic leadership roles. Results Of all 1029 faculty members invited to participate in the survey, 687 (66.8%) members responded. Of the respondents, 596 (86.8%) indicated their level of willingness to take on various academic leadership roles. Multivariable analysis revealed that the predictors associated with willingness to take on leadership roles were as follows: pursuit of professional development opportunities (odds ratio [OR] 3.79, 95% CI 2.29 to 6.27); currently holding at least 1 leadership role (OR 5.37, 95% CI 3.38 to 8.53); a history of leadership training (OR 1.86, 95% CI 1.25 to 2.78); the perception that mentorship is important for one’s current role (OR 2.25, 95% CI 1.40 to 3.60); and younger age (OR 0.97, 95% CI 0.95 to 0.99). Conclusion Willingness to undertake new or additional leadership roles was associated with 2 variables related to leadership experiences, 2 variables related to perceptions of mentorship and professional development, and 1 demographic variable (younger age). Interventions that support opportunities in these areas might expand the pool and strengthen the academic leadership potential of faculty members. PMID:27331226

  12. Neuroprotective potential of phytochemicals.

    PubMed

    Kumar, G Phani; Khanum, Farhath

    2012-07-01

    Cognitive dysfunction is a major health problem in the 21st century, and many neuropsychiatric disorders and neurodegenerative disorders, such as schizophrenia, depression, Alzheimer's Disease dementia, cerebrovascular impairment, seizure disorders, head injury and Parkinsonism, can be severly functionally debilitating in nature. In course of time, a number of neurotransmitters and signaling molecules have been identified which have been considered as therapeutic targets. Conventional as well newer molecules have been tried against these targets. Phytochemicals from medicinal plants play a vital role in maintaining the brain's chemical balance by influencing the function of receptors for the major inhibitory neurotransmitters. In traditional practice of medicine, several plants have been reported to treat cognitive disorders. In this review paper, we attempt to throw some light on the use of medicinal herbs to treat cognitive disorders. In this review, we briefly deal with some medicinal herbs focusing on their neuroprotective active phytochemical substances like fatty acids, phenols, alkaloids, flavonoids, saponins, terpenes etc. The resistance of neurons to various stressors by activating specific signal transduction pathways and transcription factors are also discussed. It was observed in the review that a number of herbal medicines used in Ayurvedic practices as well Chinese medicines contain multiple compounds and phytochemicals that may have a neuroprotective effect which may prove beneficial in different neuropsychiatric and neurodegenerative disorders. Though the presence of receptors or transporters for polyphenols or other phytochemicals of the herbal preparations, in brain tissues remains to be ascertained, compounds with multiple targets appear as a potential and promising class of therapeutics for the treatment of diseases with a multifactorial etiology. PMID:23055633

  13. Neuroprotective potential of phytochemicals

    PubMed Central

    Kumar, G. Phani; Khanum, Farhath

    2012-01-01

    Cognitive dysfunction is a major health problem in the 21st century, and many neuropsychiatric disorders and neurodegenerative disorders, such as schizophrenia, depression, Alzheimer's Disease dementia, cerebrovascular impairment, seizure disorders, head injury and Parkinsonism, can be severly functionally debilitating in nature. In course of time, a number of neurotransmitters and signaling molecules have been identified which have been considered as therapeutic targets. Conventional as well newer molecules have been tried against these targets. Phytochemicals from medicinal plants play a vital role in maintaining the brain's chemical balance by influencing the function of receptors for the major inhibitory neurotransmitters. In traditional practice of medicine, several plants have been reported to treat cognitive disorders. In this review paper, we attempt to throw some light on the use of medicinal herbs to treat cognitive disorders. In this review, we briefly deal with some medicinal herbs focusing on their neuroprotective active phytochemical substances like fatty acids, phenols, alkaloids, flavonoids, saponins, terpenes etc. The resistance of neurons to various stressors by activating specific signal transduction pathways and transcription factors are also discussed. It was observed in the review that a number of herbal medicines used in Ayurvedic practices as well Chinese medicines contain multiple compounds and phytochemicals that may have a neuroprotective effect which may prove beneficial in different neuropsychiatric and neurodegenerative disorders. Though the presence of receptors or transporters for polyphenols or other phytochemicals of the herbal preparations, in brain tissues remains to be ascertained, compounds with multiple targets appear as a potential and promising class of therapeutics for the treatment of diseases with a multifactorial etiology. PMID:23055633

  14. Potential-Based Achievement Goals

    ERIC Educational Resources Information Center

    Elliot, Andrew; Murayama, Kou; Kobeisy, Ahmed; Lichtenfeld, Stephanie

    2015-01-01

    Background: Self-based achievement goals use one's own intrapersonal trajectory as a standard of evaluation, and this intrapersonal trajectory may be grounded in one's past (past-based goals) or one's future potential (potential-based goals). Potential-based goals have been overlooked in the literature to date. Aims: The primary aim of the present…

  15. Scattering theory for arbitrary potentials

    SciTech Connect

    Kadyrov, A.S.; Bray, I.; Stelbovics, A.T.; Mukhamedzhanov, A.M.

    2005-09-15

    The fundamental quantities of potential scattering theory are generalized to accommodate long-range interactions. Definitions for the scattering amplitude and wave operators valid for arbitrary interactions including potentials with a Coulomb tail are presented. It is shown that for the Coulomb potential the generalized amplitude gives the physical on-shell amplitude without recourse to a renormalization procedure.

  16. Isospectral potentials from modified factorization

    NASA Astrophysics Data System (ADS)

    Berger, Micheal S.; Ussembayev, Nail S.

    2010-08-01

    Factorization of quantum-mechanical potentials has a long history extending back to the earliest days of the subject. In the present article, the nonuniqueness of the factorization is exploited to derive new isospectral nonsingular potentials. Many one-parameter families of potentials can be generated from known potentials using a factorization that involves superpotentials defined in terms of excited states of a potential. For these cases an operator representation is available. If ladder operators are known for the original potential, then a straightforward procedure exists for defining such operators for its isospectral partners. The generality of the method is illustrated with a number of examples which may have many possible applications in atomic and molecular physics.

  17. Chemical corrosion potential in boilers

    SciTech Connect

    Bairr, D.L.; McDonough, C.J.

    1998-12-31

    Misuse or abuse of chelants has long been recognized as a potential corrosion problem in boilers. In recent years all polymer chemical treatment programs have been introduced and although they are much more benign even all polymer programs must be properly designed and controlled. Under extreme conditions a similar corrosion potential exists. This paper discusses the potential for chelant or polymer corrosion in boilers and the proper safeguards. Case histories are presented.

  18. Orbits in a logarithmic potential

    SciTech Connect

    Hooverman, R. H.

    2014-04-15

    The characteristics of charged particle orbits in the logarithmic electrostatic potential field surrounding a straight conducting wire at a fixed potential are investigated. The equations of motion of an electron in a logarithmic potential are derived, the limiting cases are considered, and the results of numerical integration of the equations of motion are presented along with sketches of a few representative orbits. (C.E.S.)

  19. The Concept of Curriculum Potential

    ERIC Educational Resources Information Center

    Ben-Peretz, Miriam

    1975-01-01

    Explores the concept of curriculum potential and argues for its utility as a construct in curriculum theory. Discusses the limitations of viewing curriculum materials strictly in accordance with their developers' objectives, and examines the concept of curriculum potential as an alternative approach to curriculum implementation and evaluation.…

  20. Limiting Spectra from Confining Potentials.

    ERIC Educational Resources Information Center

    Nieto, Michael Martin; Simmons, L. M., Jr.

    1979-01-01

    The author explains that, for confining potentials and large quantum numbers, the bound-state energies rise more rapidly as a function of n the more rapidly the potential rises with distance. However, the spectrum can rise no faster than n squared in the nonrelativistic case, or n in the relativistic case. (Author/GA)

  1. Ambipolar potential formation in TMX

    SciTech Connect

    Correll, D.L.; Allen, S.L.; Casper, T.A.

    1981-05-05

    TMX experimental data on ambipolar potential control and on the accompanying electrostatic confinement are reported. New results on the radial dependence of the central-cell confining potential are given. Radial and axial particle losses as well as scaling of the central-cell axial confinement are discussed.

  2. Working with Potentially Assaultive Clients.

    ERIC Educational Resources Information Center

    Murdach, Allison D.

    1993-01-01

    Examines potentially assaultive or preassaultive client and suggests some ways to minimize the risk of assault by such clients. Data for the article are from author's 10-year experience in providing social work services on acute psychiatric ward in large public medical center. Reviews potentially assaultive client conditions of panic, rage,…

  3. State and Local Revenue Potential.

    ERIC Educational Resources Information Center

    Quindry, Kenneth E.

    This report contains the results of an extensive study into State and local tax revenue potentials for the 15 Southern Regional Education Board (SREB) States. It identifies both the degree of current use and the potential for increased use of (1) general and selective sales and gross receipts taxes, (2) death and gift taxes, (3) property taxes,…

  4. Potential flow through channel constriction.

    USGS Publications Warehouse

    Lee, J.K.

    1984-01-01

    Potential flow through an eccentric, normal constriction of zero thickness in an infinitely long, straight channel of constant width and unit depth is studied by use of a Schwarz-Christoffel transformation. The transformation is integrated by a direct approach. Parametric equations for streamlines are obtained and used to compute an average streamline length for a potential-flow field. -from ASCE Publications Information

  5. Plasmas: Diversity, pervasiveness and potential

    SciTech Connect

    Eastman, Timothy E.

    1998-01-01

    When considered inclusively, plasma science and technology encompass immense diversity, pervasiveness and potential: diversity through numerous topical areas (see list of nearly 200 in Table II); pervasiveness with examples covering the full range of energy, time and spatial scale; and potential through innumerable current and future applications.

  6. Brain potential changes in voluntary and passive movements in humans: readiness potential and reafferent potentials.

    PubMed

    Kornhuber, Hans H; Deecke, Lüder

    2016-07-01

    A method of chronological data storage and reverse computation is described by which bio-electrical phenomena preceding 'spontaneous' events within the nervous system can be analysed if these events appear repeatedly and are capable of triggering a computer.Slow brain potentials accompanying voluntary and passive movements of the limbs were analysed by this method. These potentials were recorded from different points of the scalp from 12 healthy subjects in 94 experiments with more than 100 movements in each record. At times artifacts were superimposed upon cerebral potentials. The former were identified, and, as far as possible, eliminated.Voluntary hand or foot movements are preceded by a slowly increasing surface-negative cortical potential of 10-15 μV, called readiness potential. This potential is maximal over the contralateral precentral region, but shows bilateral spread and is larger over the frontal than over the occipital areas. The readiness potential increases with intentional engagement and is reduced by mental indifference of the subject.Voluntary movements are followed by a complex potential with an early positive phase that begins 30-90 msec after the onset of movement. The late potentials following voluntary movements are similar to those after passive movements. Both resemble the late bilateral components of the evoked potentials after electrical stimulation of peripheral nerves. Some variable differences between the early components of the potentials after the onset of active and passive movements require further investigation.No relation between the onset of voluntary movements and the phase of the alpha rhythm could be detected.Further applications of reverse computation are addressed. Similarities between the readiness potential and G. WALTER'S expectancy wave in conditioned reflexes, and the sources of artifacts through eye movements etc. are discussed. PMID:27392465

  7. Electrical potentials in stomatal complexes

    SciTech Connect

    Saftner, R.A.; Raschke, K.

    1981-06-01

    Guard cells of several species, but predominantly Commelina communis, were impaled by micropipette electrodes and potential differences measured that occurred between cell compartments and the flowing bathing medium. The wall developed a Donnan potential that was between -60 and -70 millivolt in 30 millimolar KC1 at pH 7. The density of the fixed charges ranged from 0.3 to 0.5 molar; its dependence on pH was almost identical with the titration curve of authentic polygalacturonic acid. The vacuolar potential of guard cells of Commelina communis L., Zea mays L., Nicotiana glauca Graham, Allium cepa L., and Vicia faba L. was between -40 and -50 millivolt in 30 millimolar KCl when stomata were open and about -30 millivolt when stomata were closed. The vacuolar potential of guard cells of C. communis was almost linearly related to stomatal aperture and responded to changes in the ionic strength in the bathing medium in a Nernstian manner. No specificity for any alkali ion (except Li/sup +/), ammonium, or choline appeared. Lithium caused hyperpolarization. Calcium in concentrations between 1 and 100 millimolar in the medium led to stomatal closure, also caused hyperpolarization, and triggered transient oscillations in the intracellular potential. Gradients in the electrical potential existed across stomatal complexes with open pores. When stomata closed, these gradients almost disappeared or slightly reverted; all epidermal cells were then at potentials near -30 millivolt in 30 millimolar KCl.

  8. Designing potentials by sculpturing wires

    SciTech Connect

    Della Pietra, Leonardo; Aigner, Simon; Groth, Soenke; Hagen, Christoph von; Schmiedmayer, Joerg; Bar-Joseph, Israel; Lezec, Henri J.

    2007-06-15

    Magnetic trapping potentials for atoms on atom chips are determined by the current flow in the chip wires. By modifying the shape of the conductor we can realize specialized current flow patterns and therefore microdesign the trapping potentials. We have demonstrated this by nano-machining an atom chip using the focused ion beam technique. We built a trap, a barrier, and using a Bose-Einstein Condensate as a probe we showed that by polishing the conductor edge the potential roughness on the selected wire can be reduced. Furthermore, we give different other designs and discuss the creation of a one-dimensional magnetic lattice on an atom chip.

  9. Confining potential in momentum space

    NASA Technical Reports Server (NTRS)

    Norbury, John W.; Kahana, David E.; Maung, Khin Maung

    1992-01-01

    A method is presented for the solution in momentum space of the bound state problem with a linear potential in r space. The potential is unbounded at large r leading to a singularity at small q. The singularity is integrable, when regulated by exponentially screening the r-space potential, and is removed by a subtraction technique. The limit of zero screening is taken analytically, and the numerical solution of the subtracted integral equation gives eigenvalues and wave functions in good agreement with position space calculations.

  10. Completeness for sparse potential scattering

    SciTech Connect

    Shen, Zhongwei

    2014-01-15

    The present paper is devoted to the scattering theory of a class of continuum Schrödinger operators with deterministic sparse potentials. We first establish the limiting absorption principle for both modified free resolvents and modified perturbed resolvents. This actually is a weak form of the classical limiting absorption principle. We then prove the existence and completeness of local wave operators, which, in particular, imply the existence of wave operators. Under additional assumptions on the sparse potential, we prove the completeness of wave operators. In the context of continuum Schrödinger operators with sparse potentials, this paper gives the first proof of the completeness of wave operators.

  11. The reconstruction of inflationary potentials

    NASA Astrophysics Data System (ADS)

    Lin, Jianmang; Gao, Qing; Gong, Yungui

    2016-07-01

    The observational data on the anisotropy of the cosmic microwave background constraints the scalar spectral tilt ns and the tensor to scalar ratio r which depend on the first and second derivatives of the inflaton potential. The information can be used to reconstruct the inflaton potential in the polynomial form up to some orders. However, for some classes of potentials, ns and r behave as ns(N) and r(N) universally in terms of the number of e-folds N. The universal behaviour of ns(N) can be used to reconstruct a class of inflaton potentials. By parametrizing one of the parameters ns(N), ɛ(N) and φ(N), and fitting the parameters in the models to the observational data, we obtain the constraints on the parameters and reconstruct the classes of the inflationary models which include the chaotic inflation, T-model, hilltop inflation, s-dual inflation, natural inflation and R2 inflation.

  12. Cosinusoidal Potential Now vs Then

    NASA Astrophysics Data System (ADS)

    Bartlett, David F.

    2013-01-01

    From 1993 till 1996 Virginia Trimble patiently edited a manuscript of mine entitled "Evidence in the Literature for a Cosinusoidal Potential With a Universal Wavelength". Then the wavelength was 1800 light years. Now it is 400 parsec. Why the difference?

  13. Molecular potentials and relaxation dynamics

    NASA Astrophysics Data System (ADS)

    Karo, A. M.

    1981-03-01

    The use of empirical pseudopotentials, in evaluating interatomic potentials, provides and inexpensive and convenient method for obtaining highly accurate potential curves and permits the modeling of core-valence correlation, and the inclusion of relativistic effects when these are significant. As an example, recent calculations of the chi and the a 3 Sigma + states of LiH, NaH, KH, RbH, and CsH and the chi 2 Sigma + states of their anions are discussed. Pseudopotentials, including core polarization terms, have been used to replace the core electrons, and this has been coupled with the development of compact, highly-optimized basis sets for the corresponding one- and two-electron atoms. Comparisons of the neutral potential curves with experiment and other ab initio calculations show good agreement (within 1000/cm over most of the potential curves) with the difference curves being considerably more accurate.

  14. Noncommutative potential theory: A survey

    NASA Astrophysics Data System (ADS)

    Cipriani, Fabio

    2016-07-01

    The aim of these notes is to provide an introduction to Noncommutative Potential Theory as given at I.N.D.A.M.-C.N.R.S. "Noncommutative Geometry and Applications" Lectures, Villa Mondragone-Frascati June 2014.

  15. Potentials Unlimited: A Summer Happening.

    ERIC Educational Resources Information Center

    Croskery, Beverly; Marten, Mary Elizabeth

    1980-01-01

    The article describes Potentials Unlimited, a summer camp program for gifted intermediate grade students in Cincinnati, Ohio. Aspects covered include priorities in selecting curricular activities and some of the camp activities themselves. (DLS)

  16. Experiments With Magnetic Vector Potential

    ERIC Educational Resources Information Center

    Skinner, J. W.

    1975-01-01

    Describes the experimental apparatus and method for the study of magnetic vector potential (MVP). Includes a discussion of inherent errors in the calculations involved, precision of the results, and further applications of MVP. (GS)

  17. Propagator for finite range potentials

    SciTech Connect

    Cacciari, Ilaria; Moretti, Paolo

    2006-12-15

    The Schroedinger equation in integral form is applied to the one-dimensional scattering problem in the case of a general finite range, nonsingular potential. A simple expression for the Laplace transform of the transmission propagator is obtained in terms of the associated Fredholm determinant, by means of matrix methods; the particular form of the kernel and the peculiar aspects of the transmission problem play an important role. The application to an array of delta potentials is shown.

  18. Analytical multikinks in smooth potentials

    NASA Astrophysics Data System (ADS)

    de Brito, G. P.; Correa, R. A. C.; de Souza Dutra, A.

    2014-03-01

    In this work we present an approach that can be systematically used to construct nonlinear systems possessing analytical multikink profile configurations. In contrast with previous approaches to the problem, we are able to do it by using field potentials that are considerably smoother than the ones of the doubly quadratic family of potentials. This is done without losing the capacity of writing exact analytical solutions. The resulting field configurations can be applied to the study of problems from condensed matter to braneworld scenarios.

  19. Alpha Ni optical model potentials

    NASA Astrophysics Data System (ADS)

    Billah, M. M.; Abdullah, M. N. A.; Das, S. K.; Uddin, M. A.; Basak, A. K.; Reichstein, I.; Sen Gupta, H. M.; Malik, F. B.

    2005-11-01

    The present work reports the analyses of the experimental differential cross-sections of α elastic scattering on 58,60,62,64Ni, over a wide range of incident energies, in terms of four types of optical potentials, namely shallow (molecular), deep non-monotonic, squared Woods-Saxon and semi-microscopic folding. All the four potentials produce a reasonable description of the experimental data. The potential parameters, calculated from the energy density functional theory using a realistic two-nucleon interaction, resemble closely the molecular potential parameters, which produce the best description of the experimental data for the four isotopes. The volume integrals and the energy variation of the parameters indicate the effect of the shell-model structure on the potentials. The folding potentials, without any need for renormalization, are found to describe reasonably well the elastic scattering cross-section data for the four isotopes within the energy range considered. In conformity with the previous observation on Ca isotopes, the number of nucleons, 4A=49, existing in α-like clusters in the target nucleus, is the same for the four isotopes, considered herein.

  20. MODELING WORLD BIOENERGY CROP POTENTIAL

    NASA Astrophysics Data System (ADS)

    Hagiwara, Kensuke; Hanasaki, Naota; Kanae, Shinjiro

    Bioenergy is regarded as clean energy due to its characteristics and expected to be a new support of world energy de¬mand, but there are few integrated assessments of the potential of bioenergy considering sustainable land use. We esti¬mated the global bioenergy potential with an integrated global water resources model, the H08. It can simulate the crop yields on global-scale at a spatial resolution of 0.50.5. Seven major crops in the world were considered; namely, maize, sugar beet, sugar cane, soybean, rapeseed, rice, and wheat, of which the first 5 are commonly used to produce biofuel now. Three different land-cover types were chosen as potential area for cultivation of biofuel-producing crop: fallow land, grassland, and portion of forests (excluding areas sensitive for biodiversity such as frontier forest). We attempted to estimate the maximum global bioenergy potential and it was estimated to be 1120EJ. Bioenergy potential depends on land-use limitations for the protection of bio-diversity and security of food. In another condition which assumed more land-use limitations, bioenergy potential was estimated to be 70-233EJ.

  1. Economic potential of inertial fusion

    SciTech Connect

    Nuckolls, J.H.

    1984-04-01

    Beyond the achievement of scientific feasibility, the key question for fusion energy is: does it have the economic potential to be significantly cheaper than fission and coal energy. If fusion has this high economic potential then there are compelling commercial and geopolitical incentives to accelerate the pace of the fusion program in the near term, and to install a global fusion energy system in the long term. Without this high economic potential, fusion's success depends on the failure of all alternatives, and there is no real incentive to accelerate the program. If my conjectures on the economic potential of inertial fusion are approximately correct, then inertial fusion energy's ultimate costs may be only half to two-thirds those of advanced fission and coal energy systems. Relative cost escalation is not assumed and could increase this advantage. Both magnetic and inertial approaches to fusion potentially have a two-fold economic advantage which derives from two fundamental properties: negligible fuel costs and high quality energy which makes possible more efficient generation of electricity. The wining approach to fusion may excel in three areas: electrical generating efficiency, minimum material costs, and adaptability to manufacture in automated factories. The winning approach must also rate highly in environmental potential, safety, availability factor, lifetime, small 0 and M costs, and no possibility of utility-disabling accidents.

  2. Active Spacecraft Potential Control Investigation

    NASA Astrophysics Data System (ADS)

    Torkar, K.; Nakamura, R.; Tajmar, M.; Scharlemann, C.; Jeszenszky, H.; Laky, G.; Fremuth, G.; Escoubet, C. P.; Svenes, K.

    2016-03-01

    In tenuous plasma the floating potential of sunlit spacecraft reaches tens of volts, positive. The corresponding field disturbs measurements of the ambient plasma by electron and ion sensors and can reduce micro-channel plate lifetime in electron detectors owing to large fluxes of attracted photoelectrons. Also the accuracy of electric field measurements may suffer from a high spacecraft potential. The Active Spacecraft Potential Control (ASPOC) neutralizes the spacecraft potential by releasing positive charge produced by indium ion emitters. The method has been successfully applied on other spacecraft such as Cluster and Double Star. Two ASPOC units are present on each spacecraft. Each unit contains four ion emitters, whereby one emitter per instrument is operated at a time. ASPOC for the Magnetospheric Multiscale (MMS) mission includes new developments in the design of the emitters and the electronics. New features include the use of capillaries instead of needles, new materials for the emitters and their internal thermal insulators, an extended voltage and current range of the electronics, both for ion emission and heating purposes, and a more capable control software. This enables lower spacecraft potentials, higher reliability, and a more uniform potential structure in the spacecraft's sheath compared to previous missions. Results from on-ground testing demonstrate compliance with requirements. Model calculations confirm the findings from previous applications that the plasma measurements will not be affected by the beam's space charge. Finally, the various operating modes to adapt to changing boundary conditions are described along with the main data products.

  3. Streaming potential measurements of biosurfaces

    NASA Technical Reports Server (NTRS)

    Van Wagenen, R. A.; Andrade, J. D.; Hibbs, J. B., Jr.

    1976-01-01

    A technique based on the measurement of streaming potentials has been developed to evaluate the electrokinetic region of the cell periphery. This approach is feasible for cell lines propagated in in-vitro cell cultures in monolayer form. The advantage of this system is that cells may be evaluated in the living state atttached to a substrate; it is not necessary to subject the cells to enzymatic, chemical, or mechanical trauma required to obtain monodisperse suspensions which are then normally evaluated by microelectrophoresis. In this manner, it should be possible to study the influence of substrate and environmental factors on the charge density and potential at the cell periphery. The apparatus and procedure are described as well as some results concerning the electrokinetic potential of borosilicate capillaries as a function of ionic strength, pH, and temperature. The effect that turbulence and entrance flow conditions have on accurate streaming-potential measurements is discussed. The electrokinetic potential of BALB/c 3T12 fibroblasts has been quantified as a function of pH, ionic strength, glutaraldehyde fixation, and Giemsa staining.

  4. Visualizing motion in potential wells

    NASA Astrophysics Data System (ADS)

    Jolly, Pratibha; Zollman, Dean; Rebello, N. Sanjay; Dimitrova, Albena

    1998-01-01

    The concept of potential-energy diagrams is of fundamental importance in the study of quantum physics. Yet, students are rarely exposed to this powerful alternative description in introductory classes and thus have difficulty comprehending its significance when they encounter it in beginning-level quantum courses. We describe a learning unit that incorporates a sequence of computer-interfaced experiments using dynamics or air-track systems. This unit is designed to make the learning of potential-energy diagrams less abstract. Students begin by constructing the harmonic or square-well potential diagrams using either the velocity data and assuming conservation of energy or the force-displacement graph for the elastic interaction of an object constrained by springs or bouncing off springy blocks. Then, they investigate the motion of a rider magnet interacting with a configuration of field magnets and plot directly the potential-energy diagrams using a magnetic field sensor. The ease of measurement allows exploring the motion in a large variety of potential shapes in a short duration class.

  5. RF potentials analysis using TOPICA

    NASA Astrophysics Data System (ADS)

    Milanesio, Daniele; Sorba, Marco; Maggiora, Riccardo

    2008-11-01

    Radio-frequency (RF) heating is fully dependent on edge plasma conditions and particularly on the acceleration of charged particles which can damage the antennas and surroundings. Rectified RF field induces drifts on ions that can hit the first wall, causing hot spots, sputtering, impurities, fuel dilution and, eventually, disruption. These phenomena mainly depend on the antenna geometry and materials, on the plasma density profile at the edge and on the connection patterns. The heat flux attributed to accelerated ions is somehow proportional to the RF potential in front of the antenna. Because of this, the understanding of the RF potential generation in front of the antenna is crucial for every high RF power systems, in order to predict the deleterious particle flux and therefore mitigate its effect by means of a proper design. The TOPICA code, an innovative tool realized for the analysis and design of ICRH and LH antennas, has been upgraded to evaluate the RF potential in front of the antenna. The solution of the Maxwell's equations in plasma combined with the RF field map at the plasma edge (standard outputs of TOPICA calculation) allow for the computation of the RF fields also in the plasma region. A new TOPICA module has been developed to account for a rigorous procedure to obtain the RF potentials and RF potential mitigation techniques through antenna geometrical modifications have been studied and will be presented.

  6. Dirac equations with confining potentials

    NASA Astrophysics Data System (ADS)

    Noble, J. H.; Jentschura, U. D.

    2015-01-01

    This paper is devoted to a study of relativistic eigenstates of Dirac particles which are simultaneously bound by a static Coulomb potential and added linear confining potentials. Under certain conditions, despite the addition of radially symmetric, linear confining potentials, specific bound-state energies surprisingly preserve their exact Dirac-Coulomb values. The generality of the "preservation mechanism" is investigated. To this end, a Foldy-Wouthuysen transformation is used to calculate the corrections to the spin-orbit coupling induced by the linear confining potentials. We find that the matrix elements of the effective operators obtained from the scalar, and time-like confining potentials mutually cancel for specific ratios of the prefactors of the effective operators, which must be tailored to the preservation mechanism. The result of the Foldy-Wouthuysen transformation is used to verify that the preservation is restricted (for a given Hamiltonian) to only one reference state, rather than traceable to a more general relationship among the obtained effective low-energy operators. The results derived from the nonrelativistic effective operators are compared to the fully relativistic radial Dirac equations. Furthermore, we show that the preservation mechanism does not affect antiparticle (negative-energy) states.

  7. 30 Dorados & the Sinusoidal Potential

    NASA Astrophysics Data System (ADS)

    Bartlett, David F.; Cumalat, J. P.

    2011-05-01

    The sinusoidal potential is an alternative to the Newtonian potential. In this alternative, the potential of a point mass is φ= -(GM/r) Cos[kor], where ko = 2π/ λo and λo is determined empirically to be Ro/20, Ro=8 kpc. A parallel modification to electromagnetism has also been suggested φ=-(Q/r) Exp -[kor] (Bartlett 2004). Recently an equivalent absolute value for ko has been posited: ko2= πG (α 2 me) 4 c/ (h-bar)3. The sinusoidal potential has been developed in presentations at many recent meetings of the AAS & the DDA. Generally, short-range structure (galaxies and smaller) are dominated by gravitation; long-range (clusters of galaxies and larger) by electromagnetism. 30 Dorados is still a puzzle. Why should this region of intense star formation be between the Large Magellanic Cloud and the Milky Way, but much closer to the former than the latter. Why should its size be roughly 400 pc? What is its connection to the Magellanic Stream? The sinusoidal potential may help.

  8. Non-linear potential problems

    NASA Astrophysics Data System (ADS)

    Skerget, P.; Brebbia, C. A.

    In many practical applications of boundary elements, the potential problems may be nonlinear. The use of Kirchoff's transform provides an approach to convert a nonlinear material problem into a linear one. A description of several different shape functions to define the conductivity is presented. Attention is given to the type of integral equations which are obtained if the Kirchoff's transform is applied for nonlinear material in the presence of mixed boundary conditions. The integral formulation for nonlinear radiation boundary conditions with and without potential dependent conductivity is also considered. For steady heat conduction problems with constant conductivity a boundary integral equation relating boundary values for temperatures (or potentials) and its normal derivatives over the boundary can be obtained. Applications which concern the solution of steady state conduction problems are investigated. The problems are related to a hollow cylinder, a nuclear reactor pressure vessel, and an industrial furnace.

  9. Contact potential measurement: The preamplifier

    NASA Astrophysics Data System (ADS)

    Rossi, Frank

    1992-07-01

    The factors governing the choice of preamplifier type for the vibrating capacitive probe used in contact potential measurements are examined. Two types are compared: a high input impedance voltage amplifier and a current amplifier. The latter has been increasingly used in recent years due to its great advantages in dealing with parasitic input capacitance. We extend previous analyses, elucidating other advantages of the current amplifier. Particularly important are (i) the reduction of spurious microphonic signals, implying lower systematic error, and (ii) the white noise spectrum of its equivalent contact potential noise, which allows random error to be effectively reduced by increased averaging periods.

  10. Anisotropic inflation with general potentials

    NASA Astrophysics Data System (ADS)

    Shi, JiaMing; Huang, XiaoTian; Qiu, TaoTao

    2016-04-01

    Anomalies in recent observational data indicate that there might be some "anisotropic hair" generated in an inflation period. To obtain general information about the effects of this anisotropic hair to inflation models, we studied anisotropic inflation models that involve one vector and one scalar using several types of potentials. We determined the general relationship between the degree of anisotropy and the fraction of the vector and scalar fields, and concluded that the anisotropies behave independently of the potentials. We also generalized our study to the case of multi-directional anisotropies.

  11. Antioxidant potential of Lactuca sativa.

    PubMed

    Garg, Munish; Garg, Chanchal; Mukherjee, Pulok K; Suresh, B

    2004-07-01

    The present study is based on the evaluation of antioxidant potential of a well known plant Lactuca sativa. Methanolic leaf extract was investigated for in vitro inhibition of oxidative damage induced by UV-radiations to the salmonella typhi bacteria and in vivo effect on the production of body enzymes i.e. catalase and superoxide dismutase. The lipid peroxidation masurement was also done in terms of thiobarbituric acid reactive substances (TBARS) in blood and brain of male albino wistar rats. The plant extract has shown significant antioxidant potential both in vitro and in vivo. PMID:22557144

  12. Quinoxalines Potential to Target Pathologies.

    PubMed

    Tristán-Manzano, María; Guirado, Antonio; Martínez-Esparza, María; Gálvez, Jesús; García-Peñarrubia, Pilar; Ruiz-Alcaraz, Antonio J

    2015-01-01

    The study of quinoxalines has increased immeasurably during the last two decades, due firstly to their relatively simple chemical synthesis, which has generated a vast variety of compounds with diverse structural modifications, and secondly, to the wide therapeutic potential and biological activities exhibited by this family of compounds. Quinoxalines constitute a rising biomedical class of low-molecular weight heterocyclic compounds with potential functions as antitumour, anti-inflammatory, antibacterial, antiviral, antifungal, antiparasitic and antidiabetic agents, as well as being of interest for the potential treatment of glaucoma, insomnia, cardiovascular and neurological diseases, among others. However, a deeper knowledge of the molecular targets of quinoxalines that fulfil a key role in certain pathologies is required for the development of new and more specific drugs through a rational design strategy to avoid undesirable side effects. In the present review, we summarize the most important molecular targets of the quinoxaline derivatives discovered to date, thus providing a first reference index for researchers to identify the potential targets of their quinoxalines derived collections, which could facilitate the development of new quinoxaline- based therapies. PMID:26264925

  13. Quantum mechanics without potential function

    SciTech Connect

    Alhaidari, A. D.; Ismail, M. E. H.

    2015-07-15

    In the standard formulation of quantum mechanics, one starts by proposing a potential function that models the physical system. The potential is then inserted into the Schrödinger equation, which is solved for the wavefunction, bound states energy spectrum, and/or scattering phase shift. In this work, however, we propose an alternative formulation in which the potential function does not appear. The aim is to obtain a set of analytically realizable systems, which is larger than in the standard formulation and may or may not be associated with any given or previously known potential functions. We start with the wavefunction, which is written as a bounded infinite sum of elements of a complete basis with polynomial coefficients that are orthogonal on an appropriate domain in the energy space. Using the asymptotic properties of these polynomials, we obtain the scattering phase shift, bound states, and resonances. This formulation enables one to handle not only the well-known quantum systems but also previously untreated ones. Illustrative examples are given for two- and three-parameter systems.

  14. Instructional Television: Potentials or Problems.

    ERIC Educational Resources Information Center

    Pekich, John

    The potential of instructional television (ITV) for creating excitement for learning has been demonstrated by such productions as Mr. Rogers' Neighborhood, The Electric Company, and The Adams Chronicles. However, not all producers have been this successful in merging the capabilities of television with the needs of learners, and a review of the…

  15. The Potential Impact of Vouchers

    ERIC Educational Resources Information Center

    McEwan, Patrick J.

    2004-01-01

    This article provides an updated review of recent empirical research on the potential impact of private school vouchers. It addresses 3 questions: (a) do students that use vouchers to attend a private school obtain better outcomes than would be obtained in a public school? (b) Do vouchers encourage student sorting and how does sorting affect…

  16. Molecular potentials and relaxation dynamics

    SciTech Connect

    Karo, A.M.

    1981-03-27

    The use of empirical pseudopotentials, in evaluating interatomic potentials, provides an inexpensive and convenient method for obtaining highly accurate potential curves and permits the modeling of core-valence correlation, and the inclusion of relativistic effects when these are significant. As an example, recent calculations of the chi/sup 1/..sigma../sup +/ and a/sup 3/..sigma../sup +/ states of LiH, NaH, KH, RbH, and CsH and the chi/sup 2/..sigma../sup +/ states of their anions are discussed. Pseudopotentials, including core polarization terms, have been used to replace the core electrons, and this has been coupled with the development of compact, highly-optimized basis sets for the corresponding one- and two-electron atoms. Comparisons of the neutral potential curves with experiment and other ab initio calculations show good agreement (within 1000 cm/sup -1/ over most of the potential curves) with the difference curves being considerably more accurate.

  17. Tank farm potential ignition sources

    SciTech Connect

    Scaief, C.C. III

    1996-01-01

    This document identifies equipment, instrumentation, and sensors that are located in-tank as well as ex-tank in areas that may have communication paths with the tank vapor space. For each item, and attempt is made to identify the potential for ignition of flammable vapors using a graded approach. The scope includes all 177 underground storage tanks.

  18. Evolutionary potential games on lattices

    NASA Astrophysics Data System (ADS)

    Szabó, György; Borsos, István

    2016-04-01

    Game theory provides a general mathematical background to study the effect of pair interactions and evolutionary rules on the macroscopic behavior of multi-player games where players with a finite number of strategies may represent a wide scale of biological objects, human individuals, or even their associations. In these systems the interactions are characterized by matrices that can be decomposed into elementary matrices (games) and classified into four types. The concept of decomposition helps the identification of potential games and also the evaluation of the potential that plays a crucial role in the determination of the preferred Nash equilibrium, and defines the Boltzmann distribution towards which these systems evolve for suitable types of dynamical rules. This survey draws parallel between the potential games and the kinetic Ising type models which are investigated for a wide scale of connectivity structures. We discuss briefly the applicability of the tools and concepts of statistical physics and thermodynamics. Additionally the general features of ordering phenomena, phase transitions and slow relaxations are outlined and applied to evolutionary games. The discussion extends to games with three or more strategies. Finally we discuss what happens when the system is weakly driven out of the "equilibrium state" by adding non-potential components representing games of cyclic dominance.

  19. Ionization Potentials for Isoelectronic Series.

    ERIC Educational Resources Information Center

    Agmon, Noam

    1988-01-01

    Presents a quantitative treatment of ionization potentials of isoelectronic atoms. By looking at the single-electron view of calculating the total energy of an atom, trends in the screening and effective quantum number parameters are examined. Approaches the question of determining electron affinities. (CW)

  20. Wakefield potentials of corrugated structures

    NASA Astrophysics Data System (ADS)

    Novokhatski, A.

    2015-10-01

    A corrugated structure, which is used in "dechirper" devices, is usually a pipe or two plates with small corrugations (bumps) on the walls. There is a good single-mode description of the wake potentials excited by a relativistic bunch if the wave length of the mode is much longer than the distance between the bumps in the pipe. However, ultrashort bunches, which are now used in free electron lasers, excite much higher frequency fields and the corresponding wake potentials will be very different from the single-mode description. We have made analyses of these wake potentials based on a numerical solution of Maxwell's equations. It was confirmed that the behavior of the wakefields of ultrashort bunches in corrugated structures is not much different from the fields excited usually in accelerating structures where the wake potentials are described by the exponential function. For a practical application we present results for the SLAC "dechirper." We also carried out calculations for a similar device, that was installed and measured at the Pohang Accelerator Laboratory, Korea. We find very good agreement with the experimental results.

  1. High Potentials: A CEO Perspective

    ERIC Educational Resources Information Center

    Hermans, Jeanine

    2007-01-01

    Finding high potentials has been identified as one of the major challenges for society and for higher education. But how does one find the talented individuals who will design the future of society? Can and should universities cooperate or compete with business and industry for these talents? Three CEOs reflect on this worldwide competition for…

  2. Competency Testing: Potential for Discrimination.

    ERIC Educational Resources Information Center

    McClung, Merle Steven

    1977-01-01

    This article discusses the potential for discrimination inherent in competency-based testing and suggests some provisions which might be included in a fair competency-based program. Discussed are: (1) racial discrimination; (2) inadequate phase-in periods; (3) tests which are not reliable or have not been validated; (4) inadequate matching of the…

  3. Potential Entrepreneurs Learn Managerial Skills.

    ERIC Educational Resources Information Center

    Jones, Joey; Jolley, Freddie Sue

    1979-01-01

    Describes a business education program for potential entrepreneurs in Arkansas secondary schools called Junior Executive Training (JET). JET includes management principles, investments, parliamentary procedure, banking, consumer education, business law, note taking, dictation and transcription, memory training, public speaking, human relations,…

  4. Potential Theory for Directed Networks

    PubMed Central

    Zhang, Qian-Ming; Lü, Linyuan; Wang, Wen-Qiang; Zhou, Tao

    2013-01-01

    Uncovering factors underlying the network formation is a long-standing challenge for data mining and network analysis. In particular, the microscopic organizing principles of directed networks are less understood than those of undirected networks. This article proposes a hypothesis named potential theory, which assumes that every directed link corresponds to a decrease of a unit potential and subgraphs with definable potential values for all nodes are preferred. Combining the potential theory with the clustering and homophily mechanisms, it is deduced that the Bi-fan structure consisting of 4 nodes and 4 directed links is the most favored local structure in directed networks. Our hypothesis receives strongly positive supports from extensive experiments on 15 directed networks drawn from disparate fields, as indicated by the most accurate and robust performance of Bi-fan predictor within the link prediction framework. In summary, our main contribution is twofold: (i) We propose a new mechanism for the local organization of directed networks; (ii) We design the corresponding link prediction algorithm, which can not only testify our hypothesis, but also find out direct applications in missing link prediction and friendship recommendation. PMID:23408979

  5. Sports Potentials for Physical Fitness.

    ERIC Educational Resources Information Center

    Clarke, H. Harrison, Ed.

    1978-01-01

    This report, one of a series on research into specific physical activities and their efficacy in improving and maintaining physical fitness, examines sport participation and the potential it has for developing muscular strength, muscular endurance, and circulatory-respiratory endurance. The activities consist primarily of the following twelve…

  6. Transpolar potential saturation models compared

    NASA Astrophysics Data System (ADS)

    Siscoe, G.; Raeder, J.; Ridley, A. J.

    2004-09-01

    We compare four explanations of transpolar potential saturation: (1) the magnetic field at the stagnation point weakens, thereby limiting magnetic reconnection; (2) a dimple develops at the stagnation point, which limits the inflow rate to the reconnection line; (3) the magnetopause becomes blunt and the bow shock recedes, thus giving more room for the solar wind to flow around the magnetosphere, thereby reducing the need for magnetic reconnection; (4) the region 1 current system usurps the Chapman-Ferraro current system and saturates when the J × B force it generates balances solar wind ram pressure. The paper's point is that all four mechanisms involve a limit on the strength of the region 1 current system and that the criterion for the onset of transpolar potential saturation in each mechanism is that the region 1 current system generates a magnetic field that is about as strong as the dipole field at the dayside magnetopause. This circumstance prevents tests to discriminate between the four mechanisms based on predictions that relate to their dependencies on the region 1 current system. The group as a whole, however, can be tested to see whether their common criterion that relates the onset of transpolar potential saturation to the total current flowing in the region 1 system holds. The criterion can be formulated in terms of predictions that relate transpolar potential saturation to the strength of the interplanetary electric field, solar wind ram pressure, and ionospheric conductance. Published data analyses and MHD simulations reasonably confirm these predictions.

  7. Zika: Fighting a Potential Epidemic.

    PubMed

    Berlin, Joey

    2016-01-01

    As Zika became an emerging threat, Texas scrambled to coordinate a prevention-and-response strategy against potential local transmission. TMA urged lawmakers in Washington, D.C., to agree on a funding package to combat the spread of Zika. PMID:27532808

  8. Source rock potential in Pakistan

    SciTech Connect

    Raza, H.A. )

    1991-03-01

    Pakistan contains two sedimentary basins: Indus in the east and Balochistan in the west. The Indus basin has received sediments from precambrian until Recent, albeit with breaks. It has been producing hydrocarbons since 1914 from three main producing regions, namely, the Potwar, Sulaisman, and Kirthar. In the Potwar, oil has been discovered in Cambrian, Permian, Jurassic, and Tertiary rocks. Potential source rocks are identified in Infra-Cambrian, Permian, Paleocene, and Eocene successions, but Paleocene/Eocene Patala Formation seems to be the main source of most of the oil. In the Sulaiman, gas has been found in Cretaceous and Tertiary; condensate in Cretaceous rocks. Potential source rocks are indicated in Cretaceous, Paleocene, and Eocene successions. The Sembar Formation of Early Cretaceous age appears to be the source of gas. In the Kirthar, oil and gas have been discovered in Cretaceous and gas has been discovered in paleocene and Eocene rocks. Potential source rocks are identified in Kirthar and Ghazij formations of Eocene age in the western part. However, in the easter oil- and gas-producing Badin platform area, Union Texas has recognized the Sembar Formation of Early Cretaceous age as the only source of Cretaceous oil and gas. The Balochistan basin is part of an Early Tertiary arc-trench system. The basin is inadequately explored, and there is no oil or gas discovery so far. However, potential source rocks have been identified in Eocene, Oligocene, Miocene, and Pliocene successions based on geochemical analysis of surface samples. Mud volcanoes are present.

  9. Revisiting double Dirac delta potential

    NASA Astrophysics Data System (ADS)

    Ahmed, Zafar; Kumar, Sachin; Sharma, Mayank; Sharma, Vibhu

    2016-07-01

    We study a general double Dirac delta potential to show that this is the simplest yet still versatile solvable potential to introduce double wells, avoided crossings, resonances and perfect transmission (T = 1). Perfect transmission energies turn out to be the critical property of symmetric and anti-symmetric cases wherein these discrete energies are found to correspond to the eigenvalues of a Dirac delta potential placed symmetrically between two rigid walls. For well(s) or barrier(s), perfect transmission (or zero reflectivity, R(E)) at energy E=0 is non-intuitive. However, this has been found earlier and called the ‘threshold anomaly’. Here we show that it is a critical phenomenon and we can have 0≤slant R(0)\\lt 1 when the parameters of the double delta potential satisfy an interesting condition. We also invoke a zero-energy and zero curvature eigenstate (\\psi (x)={Ax}+B) of the delta well between two symmetric rigid walls for R(0)=0. We resolve that the resonant energies and the perfect transmission energies are different and they arise differently.

  10. Potential-pH Diagrams.

    ERIC Educational Resources Information Center

    Barnum, Dennis W.

    1982-01-01

    Potential-pH diagrams show the domains of redoxpotential and pH in which major species are most stable. Constructing such diagrams provides students with opportunities to decide what species must be considered, search literature for equilibrium constants and free energies of formation, and practice in using the Nernst equation. (Author/JN)

  11. Allergenic potential of novel foods.

    PubMed

    Meredith, Clive

    2005-11-01

    Concerns have been expressed that the introduction of novel foods into the diet might lead to the development of new food allergies in consumers. Novel foods can be conveniently divided into GM and non-GM categories. Decision-tree approaches (e.g. International Life Sciences Institute-International Food Biotechnology Council and WHO/FAO) to assess the allergenic potential of GM foods were developed following the discovery, during product development, of the allergenic potential of GM soyabean expressing a gene encoding a storage protein from Brazil nut (Bertolletia excelsa). Within these decision trees considerations include: the source of the transgene; amino acid homology with known allergens; cross-reactivity with IgE from food-allergic individuals; resistance to proteolysis; prediction using animal models of food allergy. Such decision trees are under constant review as new knowledge and improved models emerge, but they provide a useful framework for the assessment of the allergenic potential of GM foods. For novel non-GM foods the assessment of allergenic potential is more subjective; some foods or food ingredients will need no assessment other than a robust protein assay to demonstrate the absence of protein. Where protein is present in the novel non-GM food, hazard and risk assessments need to be made in terms of the quantity of protein that might be consumed, the identity of individual protein components and their relationships to known food allergens. Where necessary, this assessment would extend to serum screening for potential cross-reactivities, skin-prick tests in previously-sensitised individuals and double-blind placebo-controlled food challenges. PMID:16313692

  12. The Biodiversity Informatics Potential Index

    PubMed Central

    2011-01-01

    Background Biodiversity informatics is a relatively new discipline extending computer science in the context of biodiversity data, and its development to date has not been uniform throughout the world. Digitizing effort and capacity building are costly, and ways should be found to prioritize them rationally. The proposed 'Biodiversity Informatics Potential (BIP) Index' seeks to fulfill such a prioritization role. We propose that the potential for biodiversity informatics be assessed through three concepts: (a) the intrinsic biodiversity potential (the biological richness or ecological diversity) of a country; (b) the capacity of the country to generate biodiversity data records; and (c) the availability of technical infrastructure in a country for managing and publishing such records. Methods Broadly, the techniques used to construct the BIP Index were rank correlation, multiple regression analysis, principal components analysis and optimization by linear programming. We built the BIP Index by finding a parsimonious set of country-level human, economic and environmental variables that best predicted the availability of primary biodiversity data accessible through the Global Biodiversity Information Facility (GBIF) network, and constructing an optimized model with these variables. The model was then applied to all countries for which sufficient data existed, to obtain a score for each country. Countries were ranked according to that score. Results Many of the current GBIF participants ranked highly in the BIP Index, although some of them seemed not to have realized their biodiversity informatics potential. The BIP Index attributed low ranking to most non-participant countries; however, a few of them scored highly, suggesting that these would be high-return new participants if encouraged to contribute towards the GBIF mission of free and open access to biodiversity data. Conclusions The BIP Index could potentially help in (a) identifying countries most likely to

  13. Equilibrium Potentials of Membrane Electrodes

    PubMed Central

    Wang, Jui H.; Copeland, Eva

    1973-01-01

    A simple thermodynamic theory of the equilibrium potentials of membrane electrodes is formulated and applied to the glass electrode for measurement of pH. The new formulation assumes the selective adsorption or binding of specific ions on the surface of the membrane which may or may not be permeable to the ion, and includes the conventional derivation based on reversible ion transport across membranes as a special case. To test the theory, a platinum wire was coated with a mixture of stearic acid and methyl-tri-n-octyl-ammonium stearate. When this coated electrode was immersed in aqueous phosphate solution, its potential was found to be a linear function of pH from pH 2 to 12 with a slope equal to the theoretical value of 59.0 mV per pH unit at 24°. PMID:4516194

  14. Mismatch Negativity: Translating the Potential

    PubMed Central

    Todd, Juanita; Harms, Lauren; Schall, Ulrich; Michie, Patricia T.

    2013-01-01

    The mismatch negativity (MMN) component of the auditory event-related potential has become a valuable tool in cognitive neuroscience. Its reduced size in persons with schizophrenia is of unknown origin but theories proposed include links to problems in experience-dependent plasticity reliant on N-methyl-d-aspartate glutamate receptors. In this review we address the utility of this tool in revealing the nature and time course of problems in perceptual inference in this illness together with its potential for use in translational research testing animal models of schizophrenia-related phenotypes. Specifically, we review the reasons for interest in MMN in schizophrenia, issues pertaining to the measurement of MMN, its use as a vulnerability index for the development of schizophrenia, the pharmacological sensitivity of MMN and the progress in developing animal models of MMN. Within this process we highlight the challenges posed by knowledge gaps pertaining to the tool and the pharmacology of the underlying system. PMID:24391602

  15. Virulence Potential of Fusogenic Orthoreoviruses

    PubMed Central

    Cheng, Peter K.C.; Lai, Mary Y.Y.; Leung, Peter C.K.; Wong, Kitty K.Y.; Lee, W.Y.; Lim, Wilina W.L.

    2012-01-01

    Several severe respiratory virus infections that have emerged during the past decade originated in animals, including bats. In Indonesia, exposure to bats has been associated with increased risk of acquiring orthoreovirus infection. Although orthoreovirus infections are mild and self-limiting, we explored their potential for evolution into a more virulent form. We used conventional virus culture, electron microscopy, and molecular sequencing to isolate and identify orthoreoviruses from 3 patients in whom respiratory tract infection developed after travel to Indonesia. Virus characterization by plaque-reduction neutralization testing showed antigenic similarity, but sequencing of the small segment genes suggested virus reassortment, which could lead to increased virulence. Bats as a reservoir might contribute to virus evolution and genetic diversity, giving orthoreoviruses the potential to become more virulent. Evolution of this virus should be closely monitored so that prevention and control measures can be taken should it become more virulent. PMID:22608100

  16. Pharmacological potential of cerium oxidenanoparticles

    NASA Astrophysics Data System (ADS)

    Celardo, Ivana; Pedersen, Jens Z.; Traversa, Enrico; Ghibelli, Lina

    2011-04-01

    Nanotechnology promises a revolution in pharmacology to improve or create ex novo therapies. Cerium oxidenanoparticles (nanoceria), well-known as catalysts, possess an astonishing pharmacological potential due to their antioxidant properties, deriving from a fraction of Ce3+ ions present in CeO2. These defects, compensated by oxygen vacancies, are enriched at the surface and therefore in nanosized particles. Reactions involving redox cycles between the Ce3+ and Ce4+oxidation states allow nanoceria to react catalytically with superoxide and hydrogen peroxide, mimicking the behavior of two key antioxidant enzymes, superoxide dismutase and catalase, potentially abating all noxious intracellularreactive oxygen species (ROS) via a self-regenerating mechanism. Hence nanoceria, apparently well tolerated by the organism, might fight chronic inflammation and the pathologies associated with oxidative stress, which include cancer and neurodegeneration. Here we review the biological effects of nanoceria as they emerge from in vitro and in vivo studies, considering biocompatibility and the peculiar antioxidant mechanisms.

  17. Liquefaction potential index: Field assessment

    USGS Publications Warehouse

    Toprak, S.; Holzer, T.L.

    2003-01-01

    Cone penetration test (CPT) soundings at historic liquefaction sites in California were used to evaluate the predictive capability of the liquefaction potential index (LPI), which was defined by Iwasaki et al. in 1978. LPI combines depth, thickness, and factor of safety of liquefiable material inferred from a CPT sounding into a single parameter. LPI data from the Monterey Bay region indicate that the probability of surface manifestations of liquefaction is 58 and 93%, respectively, when LPI equals or exceeds 5 and 15. LPI values also generally correlate with surface effects of liquefaction: Decreasing from a median of 12 for soundings in lateral spreads to 0 for soundings where no surface effects were reported. The index is particularly promising for probabilistic liquefaction hazard mapping where it may be a useful parameter for characterizing the liquefaction potential of geologic units.

  18. Nanobiocatalysis and Its Potential Applications

    SciTech Connect

    Kim, Jungbae; Grate, Jay W.; Wang, Ping

    2008-11-01

    Nanobiocatalysis with enzymes incorporated into nanostructured materials have emerged as a rapidly growing area. Structures including nanoporous media, nanofibers, carbon nanotubes, and nanoparticles have been found to be efficient in manipulating the nanoscale environment of the enzyme and thus promising exciting advances in many areas of enzyme technology. This review will describe these recent developments in nanobiocatalysis and their potential applications in various fields such as trypsin digestion in proteomic analysis, antifouling, biofuel cells, and biosensors.

  19. Potential methane reservoirs beneath Antarctica.

    PubMed

    Wadham, J L; Arndt, S; Tulaczyk, S; Stibal, M; Tranter, M; Telling, J; Lis, G P; Lawson, E; Ridgwell, A; Dubnick, A; Sharp, M J; Anesio, A M; Butler, C E H

    2012-08-30

    Once thought to be devoid of life, the ice-covered parts of Antarctica are now known to be a reservoir of metabolically active microbial cells and organic carbon. The potential for methanogenic archaea to support the degradation of organic carbon to methane beneath the ice, however, has not yet been evaluated. Large sedimentary basins containing marine sequences up to 14 kilometres thick and an estimated 21,000 petagrams (1 Pg equals 10(15) g) of organic carbon are buried beneath the Antarctic Ice Sheet. No data exist for rates of methanogenesis in sub-Antarctic marine sediments. Here we present experimental data from other subglacial environments that demonstrate the potential for overridden organic matter beneath glacial systems to produce methane. We also numerically simulate the accumulation of methane in Antarctic sedimentary basins using an established one-dimensional hydrate model and show that pressure/temperature conditions favour methane hydrate formation down to sediment depths of about 300 metres in West Antarctica and 700 metres in East Antarctica. Our results demonstrate the potential for methane hydrate accumulation in Antarctic sedimentary basins, where the total inventory depends on rates of organic carbon degradation and conditions at the ice-sheet bed. We calculate that the sub-Antarctic hydrate inventory could be of the same order of magnitude as that of recent estimates made for Arctic permafrost. Our findings suggest that the Antarctic Ice Sheet may be a neglected but important component of the global methane budget, with the potential to act as a positive feedback on climate warming during ice-sheet wastage. PMID:22932387

  20. California Industrial Energy Efficiency Potential

    SciTech Connect

    Coito, Fred; Worrell, Ernst; Price, Lynn; Masanet, Eric; RafaelFriedmann; Rufo, Mike

    2005-06-01

    This paper presents an overview of the modeling approach andhighlights key findings of a California industrial energy efficiencypotential study. In addition to providing estimates of technical andeconomic potential, the study examines achievable program potential undervarious program-funding scenarios. The focus is on electricity andnatural gas savings for manufacturing in the service territories ofCalifornia's investor-owned utilities (IOUs). The assessment is conductedby industry type and by end use. Both crosscutting technologies andindustry-specific process measures are examined. Measure penetration intothe marketplace is modeled as a function of customer awareness, measurecost effectiveness, and perceived market barriers. Data for the studycomes from a variety of sources, including: utility billing records, theEnergy Information Association (EIA) Manufacturing Energy ConsumptionSurvey (MECS), state-sponsored avoided cost studies, energy efficiencyprogram filings, and technology savings and cost data developed throughLawrence Berkeley National Laboratory (LBNL). The study identifies 1,706GWh and 47 Mth (million therms) per year of achievable potential over thenext twelve years under recent levels of program expenditures, accountingfor 5.2 percent of industrial electricity consumption and 1.3 percent ofindustrial natural gas consumption. These estimates grow to 2,748 GWh and192 Mth per year if all cost-effective and achievable opportunities arepursued. Key industrial electricity end uses, in terms of energy savingspotential, include compressed air and pumping systems that combine toaccount for about half of the total achievable potential estimates. Fornatural gas, savings are concentrated in the boiler and process heatingend uses, accounting for over 99 percent to total achievablepotential.

  1. Optical Potential Field Mapping System

    NASA Technical Reports Server (NTRS)

    Reid, Max B. (Inventor)

    1996-01-01

    The present invention relates to an optical system for creating a potential field map of a bounded two dimensional region containing a goal location and an arbitrary number of obstacles. The potential field mapping system has an imaging device and a processor. Two image writing modes are used by the imaging device, electron deposition and electron depletion. Patterns written in electron deposition mode appear black and expand. Patterns written in electron depletion mode are sharp and appear white. The generated image represents a robot's workspace. The imaging device under processor control then writes a goal location in the work-space using the electron deposition mode. The black image of the goal expands in the workspace. The processor stores the generated images, and uses them to generate a feedback pattern. The feedback pattern is written in the workspace by the imaging device in the electron deposition mode to enhance the expansion of the original goal pattern. After the feedback pattern is written, an obstacle pattern is written by the imaging device in the electron depletion mode to represent the obstacles in the robot's workspace. The processor compares a stored image to a previously stored image to determine a change therebetween. When no change occurs, the processor averages the stored images to produce the potential field map.

  2. Potential formulation of sleep dynamics

    NASA Astrophysics Data System (ADS)

    Phillips, A. J. K.; Robinson, P. A.

    2009-02-01

    A physiologically based model of the mechanisms that control the human sleep-wake cycle is formulated in terms of an equivalent nonconservative mechanical potential. The potential is analytically simplified and reduced to a quartic two-well potential, matching the bifurcation structure of the original model. This yields a dynamics-based model that is analytically simpler and has fewer parameters than the original model, allowing easier fitting to experimental data. This model is first demonstrated to semiquantitatively match the dynamics of the physiologically based model from which it is derived, and is then fitted directly to a set of experimentally derived criteria. These criteria place rigorous constraints on the parameter values, and within these constraints the model is shown to reproduce normal sleep-wake dynamics and recovery from sleep deprivation. Furthermore, this approach enables insights into the dynamics by direct analogies to phenomena in well studied mechanical systems. These include the relation between friction in the mechanical system and the timecourse of neurotransmitter action, and the possible relation between stochastic resonance and napping behavior. The model derived here also serves as a platform for future investigations of sleep-wake phenomena from a dynamical perspective.

  3. Inflationary potentials in DBI models

    SciTech Connect

    Bessada, Dennis; Kinney, William H.; Tzirakis, Konstantinos E-mail: whkinney@buffalo.edu

    2009-09-01

    We study DBI inflation based upon a general model characterized by a power-law flow parameter ε(φ) ∝ φ{sup α} and speed of sound c{sub s}(φ) ∝ φ{sup β}, where α and β are constants. We show that in the slow-roll limit this general model gives rise to distinct inflationary classes according to the relation between α and β and to the time evolution of the inflaton field, each one corresponding to a specific potential; in particular, we find that the well-known canonical polynomial (large- and small-field), hybrid and exponential potentials also arise in this non-canonical model. We find that these non-canonical classes have the same physical features as their canonical analogs, except for the fact that the inflaton field evolves with varying speed of sound; also, we show that a broad class of canonical and D-brane inflation models are particular cases of this general non-canonical model. Next, we compare the predictions of large-field polynomial models with the current observational data, showing that models with low speed of sound have red-tilted scalar spectrum with low tensor-to-scalar ratio, in good agreement with the observed values. These models also show a correlation between large non-gaussianity with low tensor amplitudes, which is a distinct signature of DBI inflation with large-field polynomial potentials.

  4. Prodigiosin and its potential applications.

    PubMed

    Darshan, N; Manonmani, H K

    2015-09-01

    Since a decade, there has been a strong consumer demand for more natural products. This has augmented inclination towards substitution of synthetic colorants with natural pigments. Natural pigments not only have the capacity to increase the marketability of products, they also demonstrate valuable biological activities as antioxidants and anticancer agents. There is a long history of exploitation of natural products produced by bacteria as sources of pharmaceutically important, bioactive compounds. Among natural pigments, pigments from microbial sources are potentially suitable alternatives to synthetic pigments. The red pigment prodigiosin (PG) has unusual properties, which have long been documented. The red-pigmented prodiginines are bioactive secondary metabolites produced by both Gram-negative and Gram-positive bacteria. Prodigiosins are characterized by a common pyrrolyl pyrromethene skeleton, and the biological role of these pigments in the producer organisms remains unclear. Bacterial prodigiosins and their synthetic derivatives are effective proapoptotic agents against various cancer cell lines, with multiple cellular targets including multi-drug resistant cells with little or no toxicity towards normal cell lines. However, research into the biology of pigment production will stimulate interest in the bioengineering of strains to synthesize useful prodiginine derivatives. This review article highlights the characteristics and potential applications of prodigiosin pigment from Serratia as prodigiosins are real potential therapeutic drugs. PMID:26344956

  5. Peak load management: Potential options

    SciTech Connect

    Englin, J.E.; De Steese, J.G.; Schultz, R.W.; Kellogg, M.A.

    1989-10-01

    This report reviews options that may be alternatives to transmission construction (ATT) applicable both generally and at specific locations in the service area of the Bonneville Power Administration (BPA). Some of these options have potential as specific alternatives to the Shelton-Fairmount 230-kV Reinforcement Project, which is the focus of this study. A listing of 31 peak load management (PLM) options is included. Estimated costs and normalized hourly load shapes, corresponding to the respective base load and controlled load cases, are considered for 15 of the above options. A summary page is presented for each of these options, grouped with respect to its applicability in the residential, commercial, industrial, and agricultural sectors. The report contains comments on PLM measures for which load shape management characteristics are not yet available. These comments address the potential relevance of the options and the possible difficulty that may be encountered in characterizing their value should be of interest in this investigation. The report also identifies options that could improve the efficiency of the three customer utility distribution systems supplied by the Shelton-Fairmount Reinforcement Project. Potential cogeneration options in the Olympic Peninsula are also discussed. These discussions focus on the options that appear to be most promising on the Olympic Peninsula. Finally, a short list of options is recommended for investigation in the next phase of this study. 9 refs., 24 tabs.

  6. Neuronal avalanches and coherence potentials

    NASA Astrophysics Data System (ADS)

    Plenz, D.

    2012-05-01

    The mammalian cortex consists of a vast network of weakly interacting excitable cells called neurons. Neurons must synchronize their activities in order to trigger activity in neighboring neurons. Moreover, interactions must be carefully regulated to remain weak (but not too weak) such that cascades of active neuronal groups avoid explosive growth yet allow for activity propagation over long-distances. Such a balance is robustly realized for neuronal avalanches, which are defined as cortical activity cascades that follow precise power laws. In experiments, scale-invariant neuronal avalanche dynamics have been observed during spontaneous cortical activity in isolated preparations in vitro as well as in the ongoing cortical activity of awake animals and in humans. Theory, models, and experiments suggest that neuronal avalanches are the signature of brain function near criticality at which the cortex optimally responds to inputs and maximizes its information capacity. Importantly, avalanche dynamics allow for the emergence of a subset of avalanches, the coherence potentials. They emerge when the synchronization of a local neuronal group exceeds a local threshold, at which the system spawns replicas of the local group activity at distant network sites. The functional importance of coherence potentials will be discussed in the context of propagating structures, such as gliders in balanced cellular automata. Gliders constitute local population dynamics that replicate in space after a finite number of generations and are thought to provide cellular automata with universal computation. Avalanches and coherence potentials are proposed to constitute a modern framework of cortical synchronization dynamics that underlies brain function.

  7. Whole Protein Native Fitness Potentials

    NASA Astrophysics Data System (ADS)

    Faraggi, Eshel; Kloczkowski, Andrzej

    2013-03-01

    Protein structure prediction can be separated into two tasks: sample the configuration space of the protein chain, and assign a fitness between these hypothetical models and the native structure of the protein. One of the more promising developments in this area is that of knowledge based energy functions. However, standard approaches using pair-wise interactions have shown shortcomings demonstrated by the superiority of multi-body-potentials. These shortcomings are due to residue pair-wise interaction being dependent on other residues along the chain. We developed a method that uses whole protein information filtered through machine learners to score protein models based on their likeness to native structures. For all models we calculated parameters associated with the distance to the solvent and with distances between residues. These parameters, in addition to energy estimates obtained by using a four-body-potential, DFIRE, and RWPlus were used as training for machine learners to predict the fitness of the models. Testing on CASP 9 targets showed that our method is superior to DFIRE, RWPlus, and the four-body potential, which are considered standards in the field.

  8. Bio-potential amplifier for potential gradient measurements

    NASA Astrophysics Data System (ADS)

    Bermúdez, Andrea N.; Spinelli, Enrique M.; Muravchik, Carlos H.

    2007-11-01

    This work proposes a bio-potential amplifier suitable for measurements from an electric potential gradient sensor, in electro-encephalography (EEG). The sensor is an array made by three electrodes placed on the vertices of an equilateral triangle of reduced size. Measuring the gradient requires small separation between electrodes hence, very low amplitude signals, of a few μV, are obtained. Therefore, it is important to minimize amplifier noise and electromagnetic interference effects. In the proposed scheme, the first stage is a passive and balanced ac-coupling network adapted to the gradient configuration and the second stage is an 80 dB gain amplifier. The implementation requires a reduced number of components. Therefore, the circuit can be mounted just above the electrodes (active electrodes). The proposed amplifier was built and tested. It achieves a CMRR of 125dB at 50 Hz and an equivalent input noise voltage of 0,3μV RMS in the band 0.5 - 500 Hz. Finally, some preliminary results in the detection of occipital alpha rhythm are presented.

  9. New methods in potential theory

    NASA Astrophysics Data System (ADS)

    Kondratyev, B. P.

    2011-09-01

    A theory of equigravitating bodies by which external force fields of volumetric axially symmetric figures can be represented by unitary integrals is developed. This theory is being developed in three directions. The first is connected with the proof of the existence of equigravitating line segments. Such line segments can have both real and imaginary distributions of density; however, the mass and external potential remain real values. The ends of line segments coincide with special points (these are cusp points on the surfaces or special points of the analytical continuation of the external potential inside the body). At two special points, the body has only one line equigravitating segment, otherwise the line segments are compound or form equigravitating "skeletons." At the isolated special points, external gravitational fields can be presented by a set of line segments and mass points. The second direction is based on a representation of the external gravitational field of volumetric axially symmetric figures with an equator plane by means of potentials of flat round disks. Such disks are obtained on the line segments with symmetric density distributions. The return is always true: for homogeneous or any nonuniform round disk, it is possible to find an equigravitating line segment. It manages to construct chains of "spheroid-disk-line segment" equigravitating bodies. The third direction of this theory is connected with the development and expansion on the scope of the method of confocal transformations. This method is modified and applied not only to continuous homogeneous ellipsoids, but also to non-uniform stratified ellipsoids with a stratification of the general type, as well as to homogeneous and nonuniform shells. Any elementary or thick ellipsoidal shells (and continuous nonuniform stratified ellipsoids) connected by special confocal transformations equigravitate each other.

  10. Dirac solutions for quaternionic potentials

    SciTech Connect

    De Leo, Stefano Giardino, Sergio

    2014-02-15

    The Dirac equation is solved for quaternionic potentials, i V{sub 0} + j W{sub 0} (V{sub 0}∈R , W{sub 0}∈C). The study shows two different solutions. The first one contains particle and anti-particle solutions and leads to the diffusion, tunneling, and Klein energy zones. The standard solution is recovered taking the complex limit of this solution. The second solution, which does not have a complex counterpart, can be seen as a V{sub 0}-antiparticle or |W{sub 0}|-particle solution.

  11. New oilseeds boast feedstock potential

    SciTech Connect

    Not Available

    1982-03-24

    Researchers in the United States are investigating the chemical potential of the Chinese tallow tree and the buffalo gourd. It is estimated that the Houston area of Texas could yield up to 70lb of seeds per tree per year. The oily component of the seed is recovered by solvent extraction and the product may some day compete with petroleum-based waxes or fats. In contrast to the Chinese tallow tree, which grows near swamps and marshes, the buffalo gourd is a desert plant. Experiments are underway aimed at improving the yield of the plant by hybridization and other genetic manipulations, and also to come up with an efficient harvesting technique.

  12. Interference effects in potential wells

    NASA Astrophysics Data System (ADS)

    Mullin, W. J.; Laloë, F.

    2015-05-01

    We propose using an array of potential wells as an interferometer in which the beam splitters are provided by tunneling during an appropriate time through the barrier between wells. This arrangement allows demonstration of generalized Hong-Ou-Mandel effects with multiple particles traversing one or several beam splitters. Other interferometer effects can occur, including a violation of the Bell-Clauser-Horne-Shimony-Holt form of the Bell inequality. With interactions, one sees various effects, including so-called fermionization, collective tunneling, and self-trapping.

  13. The cool potential of gluons

    NASA Astrophysics Data System (ADS)

    Peshier*, André; Giovannoni, Dino

    2016-01-01

    We put forward the idea that the quark-gluon plasma might exist way below the usual confinement temperature Tc. Our argument rests on the possibility that the plasma produced in heavy-ion collisions could reach a transient quasi-equilibrium with ‘over-occupied’ gluon density, as advocated by Blaizot et al. Taking further into account that gluons acquire an effective mass by interaction effects, they can have a positive chemical potential and therefore behave similarly to non-relativistic bosons. Relevant properties of this dense state of interacting gluons, which we dub serried glue, can then be inferred on rather general grounds from Maxwell's relation.

  14. Thin film mixed potential sensors

    DOEpatents

    Garzon, Fernando H.; Brosha, Eric L.; Mukundan, Rangachary

    2007-09-04

    A mixed potential sensor for oxidizable or reducible gases and a method of making. A substrate is provided and two electrodes are formed on a first surface of the substrate, each electrode being formed of a different catalytic material selected to produce a differential voltage between the electrodes from electrochemical reactions of the gases catalyzed by the electrode materials. An electrolytic layer of an electrolyte is formed over the electrodes to cover a first portion of the electrodes from direct exposure to the gases with a second portion of the electrodes uncovered for direct exposure to the gases.

  15. Leptin: a potential novel antidepressant.

    PubMed

    Lu, Xin-Yun; Kim, Chung Sub; Frazer, Alan; Zhang, Wei

    2006-01-31

    Leptin, a hormone secreted from adipose tissue, was originally discovered to regulate body weight. The localization of the leptin receptor in limbic structures suggests a potential role for leptin in emotional processes. Here, we show that rats exposed to chronic unpredictable stress and chronic social defeat exhibit low leptin levels in plasma. Systemic leptin treatment reversed the hedonic-like deficit induced by chronic unpredictable stress and improved behavioral despair dose-dependently in the forced swim test (FST), a model widely used for screening potential antidepressant efficacy. The behavioral effects of leptin in the FST were accompanied by increased neuronal activation in limbic structures, particularly in the hippocampus. Intrahippocampal infusion of leptin produced a similar antidepressant-like effect in the FST as its systemic administration. By contrast, infusion of leptin into the hypothalamus decreased body weight but had no effect on FST behavior. These findings suggest that: (i) impaired leptin production and secretion may contribute to chronic stress-induced depression-like phenotypes, (ii) the hippocampus is a brain site mediating leptin's antidepressant-like activity, and (iii) elevating leptin signaling in brain may represent a novel approach for the treatment of depressive disorders. PMID:16423896

  16. Therapeutic potential of cannabinoid medicines.

    PubMed

    Robson, P J

    2014-01-01

    Cannabis was extensively used as a medicine throughout the developed world in the nineteenth century but went into decline early in the twentieth century ahead of its emergence as the most widely used illicit recreational drug later that century. Recent advances in cannabinoid pharmacology alongside the discovery of the endocannabinoid system (ECS) have re-ignited interest in cannabis-based medicines. The ECS has emerged as an important physiological system and plausible target for new medicines. Its receptors and endogenous ligands play a vital modulatory role in diverse functions including immune response, food intake, cognition, emotion, perception, behavioural reinforcement, motor co-ordination, body temperature, wake/sleep cycle, bone formation and resorption, and various aspects of hormonal control. In disease it may act as part of the physiological response or as a component of the underlying pathology. In the forefront of clinical research are the cannabinoids delta-9-tetrahydrocannabinol and cannabidiol, and their contrasting pharmacology will be briefly outlined. The therapeutic potential and possible risks of drugs that inhibit the ECS will also be considered. This paper will then go on to review clinical research exploring the potential of cannabinoid medicines in the following indications: symptomatic relief in multiple sclerosis, chronic neuropathic pain, intractable nausea and vomiting, loss of appetite and weight in the context of cancer or AIDS, psychosis, epilepsy, addiction, and metabolic disorders. PMID:24006213

  17. Zoonotic Potential of the Microsporidia

    PubMed Central

    Mathis, Alexander; Weber, Rainer; Deplazes, Peter

    2005-01-01

    Microsporidia are long-known parasitic organisms of almost every animal group, including invertebrates and vertebrates. Microsporidia emerged as important opportunistic pathogens in humans when AIDS became pandemic and, more recently, have also increasingly been detected in otherwise immunocompromised patients, including organ transplant recipients, and in immunocompetent persons with corneal infection or diarrhea. Two species causing rare infections in humans, Encephalitozoon cuniculi and Brachiola vesicularum, had previously been described from animal hosts (vertebrates and insects, respectively). However, several new microsporidial species, including Enterocytozoon bieneusi, the most prevalent human microsporidian causing human immunodeficiency virus-associated diarrhea, have been discovered in humans, raising the question of their natural origin. Vertebrate hosts are now identified for all four major microsporidial species infecting humans (E. bieneusi and the three Encephalitozoon spp.), implying a zoonotic nature of these parasites. Molecular studies have identified phenotypic and/or genetic variability within these species, indicating that they are not uniform, and have allowed the question of their zoonotic potential to be addressed. The focus of this review is the zoonotic potential of the various microsporidia and a brief update on other microsporidia which have no known host or an invertebrate host and which cause rare infections in humans. PMID:16020683

  18. Leptin: A potential novel antidepressant

    PubMed Central

    Lu, Xin-Yun; Kim, Chung Sub; Frazer, Alan; Zhang, Wei

    2006-01-01

    Leptin, a hormone secreted from adipose tissue, was originally discovered to regulate body weight. The localization of the leptin receptor in limbic structures suggests a potential role for leptin in emotional processes. Here, we show that rats exposed to chronic unpredictable stress and chronic social defeat exhibit low leptin levels in plasma. Systemic leptin treatment reversed the hedonic-like deficit induced by chronic unpredictable stress and improved behavioral despair dose-dependently in the forced swim test (FST), a model widely used for screening potential antidepressant efficacy. The behavioral effects of leptin in the FST were accompanied by increased neuronal activation in limbic structures, particularly in the hippocampus. Intrahippocampal infusion of leptin produced a similar antidepressant-like effect in the FST as its systemic administration. By contrast, infusion of leptin into the hypothalamus decreased body weight but had no effect on FST behavior. These findings suggest that: (i) impaired leptin production and secretion may contribute to chronic stress-induced depression-like phenotypes, (ii) the hippocampus is a brain site mediating leptin's antidepressant-like activity, and (iii) elevating leptin signaling in brain may represent a novel approach for the treatment of depressive disorders. PMID:16423896

  19. Thymoma: benign appearance, malignant potential.

    PubMed

    Riedel, Richard F; Burfeind, William R

    2006-09-01

    Thymoma is a rare tumor with a largely indolent growth pattern. It does, however, have malignant potential as a result of its ability to invade locally and metastasize regionally. Often associated with a number of immune- and nonimmune-mediated paraneoplastic syndromes, patient outcomes are directly related to stage of disease and the ability to achieve a complete surgical resection. Surgery is the mainstay of treatment, with adjuvant radiation recommended for invasive thymoma. Sensitive to both chemotherapy and radiation, durable responses are achievable in incompletely resected and inoperable patients. We present two cases of thymoma followed by a general discussion with an emphasis on treatment for both early and advanced-stage disease. PMID:16951392

  20. Friedmann equation with quantum potential

    SciTech Connect

    Siong, Ch'ng Han; Radiman, Shahidan; Nikouravan, Bijan

    2013-11-27

    Friedmann equations are used to describe the evolution of the universe. Solving Friedmann equations for the scale factor indicates that the universe starts from an initial singularity where all the physical laws break down. However, the Friedmann equations are well describing the late-time or large scale universe. Hence now, many physicists try to find an alternative theory to avoid this initial singularity. In this paper, we generate a version of first Friedmann equation which is added with an additional term. This additional term contains the quantum potential energy which is believed to play an important role at small scale. However, it will gradually become negligible when the universe evolves to large scale.

  1. Characteristics of potential repository wastes

    SciTech Connect

    Cowart, C.G.; Notz, K.J.

    1992-10-01

    This report presents the results of a fully documented peer review of DOE/RW-0184, Rev. 1, Characteristics of Potential Repository Wastes''. The peer review was chaired and administered by oak Ridge National Laboratory (ORNL) for the Department of Energy (DOE), Office of Civilian Radioactive Waste Management (OCRWM) and was conducted in accordance with OCRWM QA procedure QAAP 3.3 Peer Review'' for the purpose of quailing the document for use in OCRWM quality-affecting work. The peer reviewers selected represent a wide range of experience and knowledge particularly suitable for evaluating the subject matter. A total of 596 formal comments were documented by the seven peer review panels, and all were successfully resolved. The peers reached the conclusion that DOE/RW-0184, Rev. 1, is quality determined and suitable for use in quality-affecting work.

  2. Recovery Potential After Acute Stroke

    PubMed Central

    Seitz, Rüdiger J.; Donnan, Geoffrey A.

    2015-01-01

    In acute stroke, the major factor for recovery is the early use of thrombolysis aimed at arterial recanalization and reperfusion of ischemic brain tissue. Subsequently, neurorehabilitative training critically improves clinical recovery due to augmention of postlesional plasticity. Neuroimaging and electrophysiology studies have revealed that the location and volume of the stroke lesion, the affection of nerve fiber tracts, as well as functional and structural changes in the perilesional tissue and in large-scale bihemispheric networks are relevant biomarkers of post-stroke recovery. However, associated disorders, such as mood disorders, epilepsy, and neurodegenerative diseases, may induce secondary cerebral changes or aggravate the functional deficits and, thereby, compromise the potential for recovery. PMID:26617568

  3. Gas flow in barred potentials

    NASA Astrophysics Data System (ADS)

    Sormani, Mattia C.; Binney, James; Magorrian, John

    2015-05-01

    We use a Cartesian grid to simulate the flow of gas in a barred Galactic potential and investigate the effects of varying the sound speed in the gas and the resolution of the grid. For all sound speeds and resolutions, streamlines closely follow closed orbits at large and small radii. At intermediate radii shocks arise and the streamlines shift between two families of closed orbits. The point at which the shocks appear and the streamlines shift between orbit families depends strongly on sound speed and resolution. For sufficiently large values of these two parameters, the transfer happens at the cusped orbit as hypothesized by Binney et al. over two decades ago. For sufficiently high resolutions, the flow downstream of the shocks becomes unsteady. If this unsteadiness is physical, as appears to be the case, it provides a promising explanation for the asymmetry in the observed distribution of CO.

  4. Calculate and Plot Complex Potential

    Energy Science and Technology Software Center (ESTSC)

    1998-05-05

    SOLUPLOT is a program designed to calculate and plot complex potential, pH diagrams and log oxygen activity, pH diagrams for aqueous chemical syatems, considering speciation of ligands, from free energy and thermodynamic activity data. These diagrams, commonly referred to as Eh-pH and ao2-pH diagrams, respectively, define areas of predominance in Eh-pH diagrams or ao2-pH space for chemical species of a chemical system at equilibrium. Over an area of predominance, one predominant species is at greatermore » activity than the other species of the system considered. The diagram axes, pH (a measure of hydrogen ion activity) and either Eh or log ao2 (measures of a tendency toward either oxidation or reduction) , are paremeters commonly applied in describing the chemistry of aqueous systems.« less

  5. Bacteriocins as Potential Anticancer Agents

    PubMed Central

    Kaur, Sumanpreet; Kaur, Sukhraj

    2015-01-01

    Cancer remains one of the leading causes of deaths worldwide, despite advances in its treatment and detection. The conventional chemotherapeutic agents used for the treatment of cancer have non-specific toxicity toward normal body cells that cause various side effects. Secondly, cancer cells are known to develop chemotherapy resistance in due course of treatment. Thus, the demand for novel anti-cancer agents is increasing day by day. Some of the experimental studies have reported the therapeutic potential of bacteriocins against various types of cancer cell lines. Bacteriocins are ribosomally-synthesized cationic peptides secreted by almost all groups of bacteria. Some bacteriocins have shown selective cytotoxicity toward cancer cells as compared to normal cells. This makes them promising candidates for further investigation and clinical trials. In this review article, we present the overview of the various cancer cell-specific cytotoxic bacteriocins, their mode of action and efficacies. PMID:26617524

  6. Holographic interface-particle potential

    NASA Astrophysics Data System (ADS)

    Nagasaki, Koichi; Tanida, Hiroaki; Yamaguchi, Satoshi

    2012-01-01

    We consider two mathcal{N} = {4} supersymmetric gauge theories connected by an interface and the gravity dual of this system. This interface is expressed by a fuzzy funnel solution of Nahm's equation in the gauge theory side. The gravity dual is a probe D5-brane in AdS5 × S 5. The potential energy between this interface and a test particle is calculated in both the gauge theory side and the gravity side by the expectation value of a Wilson loop. In the gauge theory it is evaluated by just substituting the classical solution to the Wilson loop. On the other hand it is done by the on-shell action of the fundamental string stretched between the AdS boundary and the D5-brane in the gravity. We show the gauge theory result and the gravity one agree with each other.

  7. Potential threats to offshore platforms

    SciTech Connect

    Jenkins, B.M.

    1988-01-01

    Increasingly spectacular acts of terrorism have led to growing concern that terrorists will move beyond the symbols of society and directly attack its technological and industrial vulnerabilities. Offshore platforms have been frequently mentioned among the potential targets terrorists might attack. This concern, however, has not resulted in extensive research like that devoted to possible threats to nuclear facilities, which have also been frequently mentioned as possible future targets of terrorists. For one thing, offshore drilling does not invoke the fear inherent in the word nuclear, a fear that translates directly into heavy security for the nuclear industry. Neither does the construction of offshore platforms provoke anything like the kind of protest generated by the construction of nuclear facilities.

  8. Potential applications of bacteriorhodopsin mutants

    PubMed Central

    Saeedi, P.; Moosaabadi, J. Mohammadian; Sebtahmadi, S. Sina; Mehrabadi, J. Fallah; Behmanesh, M.; Mekhilef, S.

    2012-01-01

    Bacteriorhodopsin (BR), a model system in biotechnology, is a G-protein dependent trans membrane protein which serves as a light driven proton pump in the cell membrane of Halobacterium salinarum. Due to the linkage of retinal to the protein, it seems colored and has numbers of versatile properties. As in vitro culture of the Halobacteria is very difficult, and isolation is time consuming and usually inefficient, production of genetically modified constructs of the protein is essential. There are three important characteristics based on protein catalytic cycle and molecular functions of photo-electric, photochromic and proton transporting, which makes this protein as a strategic molecule with potential applications in biotechnology. Such applications include protein films, used in artificial retinal implants, light modulators, three-dimensional optical memories, color photochromic sensors, photochromic and electrochromic papers and ink, biological camouflage and photo detectors for biodefense and non-defense purposes. PMID:22895057

  9. Zeta potential in ceramic industry

    NASA Technical Reports Server (NTRS)

    Lecuit, M.

    1984-01-01

    Deflocculation, electrical conductivity and zeta potential (ZP) are studied for the addition of 0 to 10000 ppm Na2SiO3 deflocculator to slips obtained from three argillaceous materials (kaolin d'Arvor, ball clay Hyplas 64, and/or Granger Clay No. 10). The quantity of Na2SO3 required to deflocculate a slip is independent of the density but differes for each clay. The ZP is directly related to the density of the slip. The higher the ZP the more stable a slip is; the value of the ZP of a mixture does not follow a simple law but the electrical resistance of a mixture does follow a simple additive law. The ZP appears to have linear relation with the specific surface of the argillaceous material.

  10. Two-phase potential flow

    NASA Technical Reports Server (NTRS)

    Wallis, Graham B.

    1989-01-01

    Some features of two recent approaches of two-phase potential flow are presented. The first approach is based on a set of progressive examples that can be analyzed using common techniques, such as conservation laws, and taken together appear to lead in the direction of a general theory. The second approach is based on variational methods, a classical approach to conservative mechanical systems that has a respectable history of application to single phase flows. This latter approach, exemplified by several recent papers by Geurst, appears generally to be consistent with the former approach, at least in those cases for which it is possible to obtain comparable results. Each approach has a justifiable theoretical base and is self-consistent. Moreover, both approaches appear to give the right prediction for several well-defined situations.

  11. Scalar Potential Model of light

    NASA Astrophysics Data System (ADS)

    Hodge, John

    2008-04-01

    Some observations of light are inconsistent with a wave--like model. Other observations of light are inconsistent with a particle--like model. A model of light is proposed wherein Newton's and Democritus's speculations are combined with the cosmological scalar potential model (SPM). The SPM was tested by confrontation with observations of galaxy HI rotation curves (RCs), asymmetric RCs, redshift, discrete redshift, galaxy central mass, and central velocity dispersion; and with observations of the Pioneer Anomaly. The resulting model of light will be tested by numerical simulation of a photon behaving in a wave-like manner such as diffusion, interference, reflection, spectrography, and the Afshar experiment. Although the SPM light model requires more work, early results are beginning to emerge that suggest possible tests because a few predictions are inconsistent with both the current particle and wave models of light and that suggest a re-interpretation of the equations of quantum mechanics.

  12. BMPs and their clinical potentials

    PubMed Central

    Kim, Meejung; Choe, Senyon

    2012-01-01

    Bone morphogenetic protein (BMP) signaling in diseases is the subject of an overwhelming array of studies. BMPs are excellent targets for treatment of various clinical disorders. Several BMPs have already been shown to be clinically beneficial in the treatment of a variety of conditions, including BMP-2 and BMP-7 that have been approved for clinical application in nonunion bone fractures and spinal fusions. With the use of BMPs increasingly accepted in spinal fusion surgeries, other therapeutic approaches targeting BMP signaling are emerging beyond applications to skeletal disorders. These approaches can further utilize next-generation therapeutic tools such as engineered BMPs and ex vivo-conditioned cell therapies. In this review, we focused to provide insights into such clinical potentials of BMPs in metabolic and vascular diseases, and in cancer. PMID:22026995

  13. Vibration exercise: the potential benefits.

    PubMed

    Cochrane, D J

    2011-02-01

    The aim of this review was to examine the physiological effects of vibration exercise (VbX), including the cardiovascular indices and to elucidate its potential use for those with compromised health. VbX has long been acknowledged as a potential modality in sport, exercise, and health sectors. Muscle force and power have been shown to increase after VbX for athletes, the aged and those with diseases, where neural factors are thought to be the main contributor. Further, similarities to the tonic vibration reflex have been used to propose that the muscle spindle plays a role in activating the muscle which could benefit those with compromised health. There is strong evidence that acute VbX can enhance upper and lower-body muscle power, and there is some indication that longer-term VbX can augment muscle power of upper and lower body extremities, although this is less convincing. It is not conclusive whether VbX increases force attributes. This has been fraught by the type and parameters used for various muscle contractions, and the different sample populations that have varied in chronological age, experience and training status. VbX provides an insufficient stimulus to enhance cardiovascular indices, where VbX cannot increase heart rate to the same extent as conventional aerobic exercise. But when conventional aerobic exercise is not possible, for example, in aged, cardiovascular compromised persons, VbX could be implemented at an early stage because it could provide a safe induction of a slight elevation of cardiovascular function indices while providing neural and myogenic benefits. In conclusion, VbX is a safe modality to increase physiological responses of reflex and muscle activity, and muscle function, for athletes, the aged and compromised health. However, further research should focus on the optimum dose relationship of frequency, amplitude and duration for the various populations. PMID:21165804

  14. The potential of the internet.

    PubMed

    Coleman, Jamie J; McDowell, Sarah E

    2012-06-01

    The internet and the World Wide Web have changed the ways that we function. As technologies grow and adapt, there is a huge potential for the internet to affect drug research and development, as well as many other aspects of clinical pharmacology. We review some of the areas of interest to date and discuss some of the potential areas in which internet-based technology can be exploited. Information retrieval from the web by health-care professionals is common, and bringing evidence-based medicine to the bedside affects the care of patients. As a primary research tool the web can provide a vast array of information in generating new ideas or exploring previous research findings. This has facilitated systematic reviewing, for example. The content of the web has become a subject of research in its own right. The web is also widely used as a research facilitator, including enhancement of communication between collaborators, provision of online research tools (such as questionnaires, management of large scale multicentre trials, registration of clinical trials) and distribution of information. Problems include information overload, ignorance of early data that are not indexed in databases, difficulties in keeping web sites up to date and assessing the validity of information retrieved. Some web-based activities are viewed with suspicion, including analysis by pharmaceutical companies of drug information to facilitate direct-to-consumer advertising of novel pharmaceuticals. Use of these technologies will continue to expand in often unexpected ways. Clinical pharmacologists must embrace internet technology and include it as a key priority in their research agenda. PMID:22360652

  15. Zeta potential control for electrophoresis cells

    NASA Technical Reports Server (NTRS)

    Fogal, G. L.

    1973-01-01

    Zeta potential arises from fact that ions tend to be adsorbed on surface of cell walls. This potential interfaces with electric field sensed by migrating particles and degrades resolution of separation. By regulating sign and magnitude of applied potential induced charge can be used to increase or decrease effective wall zeta potential.

  16. Cusp relation for the Pauli potential

    NASA Astrophysics Data System (ADS)

    Levämäki, H.; Nagy, Á.; Kokko, K.; Vitos, L.

    2014-12-01

    In orbital-free density functional theory, only a Schrödinger-like equation has to be solved for the square root of the electron density. In this equation, however, there is an extra potential in addition to the Kohn-Sham potential, the so-called Pauli potential. Cusp relations are now presented for this Pauli potential for spherically symmetric systems.

  17. The current potential of plastination.

    PubMed

    von Hagens, G; Tiedemann, K; Kriz, W

    1987-01-01

    This review surveys the potential of plastination, a technique of tissue preservation introduced eight years ago. In this process, water and lipids in biological tissues are replaced by curable polymer which are subsequently hardened, resulting in dry, odorless and durable specimens. The procedure consists of the following steps - fixation, dehydration, forced impregnation in a vacuum, and hardening. The properties of the finished specimen are determined by the class of polymer used. Silicone yields flexible, resilient specimens, allows the broadest range of application, and provides satisfactory results with minimum equipment. Specimens plastinated with an epoxy-silicone copolymer are rigid enough to be polished, but are not unbreakable. This resin is used for thick, opaque body slices and showcase specimens. Epoxy resins are used for thin (2.5 mm), transparent body or organ slices. They are cast between polyester foils or glass plates and can be used for histological investigations. Polyester resin is used for the production of opaque brain slices, which gives excellent differentiation between grey and white matter. The application of plastination in research and the production of teaching specimens is discussed with special regard to the equipment required, cost, and feasibility of the processing. PMID:3555158

  18. Topological insulators in random potentials

    NASA Astrophysics Data System (ADS)

    Pieper, Andreas; Fehske, Holger

    2016-01-01

    We investigate the effects of magnetic and nonmagnetic impurities on the two-dimensional surface states of three-dimensional topological insulators (TIs). Modeling weak and strong TIs using a generic four-band Hamiltonian, which allows for a breaking of inversion and time-reversal symmetries and takes into account random local potentials as well as the Zeeman and orbital effects of external magnetic fields, we compute the local density of states, the single-particle spectral function, and the conductance for a (contacted) slab geometry by numerically exact techniques based on kernel polynomial expansion and Green's function approaches. We show that bulk disorder refills the surface-state Dirac gap induced by a homogeneous magnetic field with states, whereas orbital (Peierls-phase) disorder preserves the gap feature. The former effect is more pronounced in weak TIs than in strong TIs. At moderate randomness, disorder-induced conducting channels appear in the surface layer, promoting diffusive metallicity. Random Zeeman fields rapidly destroy any conducting surface states. Imprinting quantum dots on a TI's surface, we demonstrate that carrier transport can be easily tuned by varying the gate voltage, even to the point where quasibound dot states may appear.

  19. Thymoquinone and its therapeutic potentials.

    PubMed

    Darakhshan, Sara; Bidmeshki Pour, Ali; Hosseinzadeh Colagar, Abasalt; Sisakhtnezhad, Sajjad

    2015-01-01

    Herbal medicine has attracted great attention in the recent years and is increasingly used as alternatives to chemical drugs. Several lines of evidence support the positive impact of medicinal plants in the prevention and cure of a wide range of diseases. Thymoquinone (TQ) is the most abundant constituent of the volatile oil of Nigella sativa seeds and most properties of N sativa are mainly attributed to TQ. A number of pharmacological actions of TQ have been investigated including anti-oxidant, anti-inflammatory, immunomodulatory, anti-histaminic, anti-microbial and anti-tumor effects. It has also gastroprotective, hepatoprotective, nephroprotective and neuroprotective activities. In addition, positive effects of TQ in cardiovascular disorders, diabetes, reproductive disorders and respiratory ailments, as well as in the treatment of bone complications as well as fibrosis have been shown. In addition, a large body of data shows that TQ has very low adverse effects and no serious toxicity. More recently, a great deal of attention has been given to this dietary phytochemical with an increasing interest to investigate it in pre-clinical and clinical researches for assessing its health benefits. Here we report on and analyze numerous properties of the active ingredient of N. sativa seeds, TQ, in the context of its therapeutic potentials for a wide range of illnesses. We also summarize the drug's possible mechanisms of action. The evidence reported sugests that TQ should be developed as a novel drug in clinical trials. PMID:25829334

  20. The potential of renewable energy

    SciTech Connect

    Not Available

    1990-03-01

    On June 27 and 28, 1989, the US Department of Energy (DOE) national laboratories were convened to discuss plans for the development of a National Energy Strategy (NES) and, in particular, the analytic needs in support of NES that could be addressed by the laboratories. As a result of that meeting, interlaboratory teams were formed to produce analytic white papers on key topics, and a lead laboratory was designated for each core laboratory team. The broad-ranging renewables assignment is summarized by the following issue statement from the Office of Policy, Planning and Analysis: to what extent can renewable energy technologies contribute to diversifying sources of energy supply What are the major barriers to greater renewable energy use and what is the potential timing of widespread commercialization for various categories of applications This report presents the results of the intensive activity initiated by the June 1989 meeting to produce a white paper on renewable energy. Scores of scientists, analysts, and engineers in the five core laboratories gave generously of their time over the past eight months to produce this document. Their generous, constructive efforts are hereby gratefully acknowledged. 126 refs., 44 figs., 32 tabs.

  1. Population research potentials in Africa.

    PubMed

    Hyden, G

    1980-01-01

    There is a need in Africa to test prevailing theories and concepts in population studies to see how they apply to this culture. Most of the prevailing perspective on population issues can be influenced by development strategies and policies affecting demographic variables. So research designed to determine the longterm consequences of rural settlement policies on subsequent access to family planning or family planning policies are also needed, as are studies which zero in on the work and results of specific population projects. The following issues are considered worth special consideration in Africa, where the vast majority of women live in rural areas where family planning services will not reach for some time. The areas of investigation which seem most pertinent in sub-saharan Africa are: side effect of contraceptive devices and agents; infertility assessments, social and medical consequences of adolescent pregnancies, the means of offering effective population education in rural African areas, the possible effects of fertility control programs on demographic transition, and potential funding sources. PMID:12336771

  2. Can nanotechnology potentiate photodynamic therapy?

    PubMed Central

    Huang, Ying-Ying; Sharma, Sulbha K.; Dai, Tianhong; Chung, Hoon; Yaroslavsky, Anastasia; Garcia-Diaz, Maria; Chang, Julie; Chiang, Long Y.

    2015-01-01

    Photodynamic therapy (PDT) uses the combination of non-toxic dyes and harmless visible light to produce reactive oxygen species that can kill cancer cells and infectious microorganisms. Due to the tendency of most photosensitizers (PS) to be poorly soluble and to form nonphotoactive aggregates, drug-delivery vehicles have become of high importance. The nanotechnology revolution has provided many examples of nanoscale drug-delivery platforms that have been applied to PDT. These include liposomes, lipoplexes, nanoemulsions, micelles, polymer nanoparticles (degradable and nondegradable), and silica nanoparticles. In some cases (fullerenes and quantum dots), the actual nanoparticle itself is the PS. Targeting ligands such as antibodies and peptides can be used to increase specificity. Gold and silver nanoparticles can provide plasmonic enhancement of PDT. Two-photon excitation or optical upconversion can be used instead of one-photon excitation to increase tissue penetration at longer wavelengths. Finally, after sections on in vivo studies and nanotoxicology, we attempt to answer the title question, “can nano-technology potentiate PDT?” PMID:26361572

  3. Biological Potential of Extraterrestrial Materials

    NASA Astrophysics Data System (ADS)

    Mautner, Michael N.; Conner, Anthony J.; Killham, Kenneth; Deamer, David W.

    1997-09-01

    Meteoritic materials are investigated as potential early planetary nutrients. Aqueous extracts of the Murchison C2 carbonaceous meteorite are utilized as a sole carbon source by microorganisms, as demonstrated by the genetically modifiedPseudomonas fluorescenceequipped with theluxgene. Nutrient effects are observed also with the soil microorganismsNocardia asteroidesandArthrobacter pascensthat reach populations up to 5 × 107CFU/ml in meteorite extracts, similar to populations in terrestrial soil extracts. Plant tissue cultures ofAsparagus officinalisandSolanum tuberosum(potato) exhibit enhanced pigmentation and some enhanced growth when meteorite extracts are added to partial nutrient media, but inhibited growth when added to full nutrient solution. The meteorite extracts lead to large increases in S, Ca, Mg, and Fe plant tissue contents as shown by X-ray fluorescence, while P, K, and Cl contents show mixed effects. In both microbiological and plant tissue experiments, the nutrient and inhibitory effects appear to be best balanced for growth at about 1:20 (extracted solid:H2O) ratios. The results suggest that solutions in cavities in meteorites can provide efficient concentrated biogenic and early nutrient environments, including high phosphate levels, which may be the limiting nutrient. The results also suggest that carbonaceous asteroid resources can sustain soil microbial activity and provide essential macronutrients for future space-based eco- systems.

  4. Potential Refinement of the ICRF

    NASA Astrophysics Data System (ADS)

    Ma, Chopo

    The ICRF analysis and data represented the state of the art in global extragalactic X/S band microwave astrometry in 1995. Similar analysis has been used to extend the ICRF with subsequent data consistent with the original catalog. Since 1995 there have been considerable advances in the geodetic/astrometric VLBI data set and analysis that would significantly improve the systematic errors stability and density of the next realization of the ICRS when the decision is made to take this step. In particular data acquired since 1990 including extensive use of the VLBA are of higher quality and astrometric utility because of changes in instrumentation schedule design and networks as well as specifically astrometric intent. The IVS (International VLBI Service for Geodesy and Astrometry) continues a systematic extension of the astrometric data set. Sufficient data distribution exists to select a better set of defining sources. Improvements in troposphere modeling will minimize known systematic astrometric errors while accurate modeling and estimation of station effects from loading and nonlinear motions should permit the reintegration of the celestial and terrestrial reference frames with Earth orientation parameters though a single VLBI solution. The differences between the current ICRF and the potential second realization will be described

  5. Potential refinement of the ICRF

    NASA Astrophysics Data System (ADS)

    Ma, Chopo

    2005-01-01

    The ICRF analysis and data represented the state of the art in global extragalactic X/S band microwave astrometry in 1995. Similar analysis has been used to extend the ICRF with subsequent data consistent with the original catalog. Since 1995 there have been considerable advances in the geodetic/astrometric VLBI data set and analysis that would significantly improve the systematic errors stability and density of the next realization of the ICRS when the decision is made to take this step. In particular data acquired since 1990 including extensive use of the VLBA are of higher quality and astrometric utility because of changes in instrumentation schedule design and networks as well as specifically astrometric intent. The IVS (International VLBI Service for Geodesy and Astrometry) continues a systematic extension of the astrometric data set. Sufficient data distribution exists to select a better set of defining sources. Improvements in troposphere modeling will minimize known systematic astrometric errors while accurate modeling and estimation of station effects from loading and nonlinear motions should permit the reintegration of the celestial and terrestrial reference frames with Earth orientation parameters though a single VLBI solution. The differences between the current ICRF and the potential second realization will be described.

  6. Potential Refinement of the ICRF

    NASA Technical Reports Server (NTRS)

    Ma, Chopo

    2003-01-01

    The analysis and data used for the ICRF represented the state of the art in global, extragalactic, X/S band microwave astrometry in 1995. The same general analysis method was used to extend the ICRF with subsequent VLBI data in a manner consistent with the original catalog. Since 1995 there have been considerable advances in the geodetic/astrometric VLBI data set and in the analysis that would significantly improve the systematic errors, stability, and density of the next realization of the ICRS when the decision is made to take this step. In particular, data acquired since 1990, including extensive use of the VLBA, are of higher quality and astrometric utility because of changes in instrumentation, schedule design, and networks as well as specifically astrometric intent. The IVS (International VLBI Service for Geodesy and Astrometry) continues to devote a portion of its observing capability to systematic extension of the astrometric data set. Sufficient data distribution exists to select a better set of defining sources. Improvements in troposphere modeling will minimize known systematic astrometric errors while accurate modeling and estimation of station effects from loading and nonlinear motions will permit the reintegration of the celestial reference frame, terrestrial reference frame and Earth orientation parameters though a single VLBI solution. The differences between the current ICRF and the potential next realization will be described.

  7. Arctic contamination poses potential danger

    NASA Astrophysics Data System (ADS)

    Bush, Susan

    Following the dissolution of the former Soviet Union, some studies have been focused on the impact of radioactive and hazardous materials released into the Arctic environment, including air, water, and ground. Contamination from radionuclides, trace metals, and hydrocarbons has been examined. Speaking at the 73rd meeting of the National Research Council's Polar Research Board held June 28 in Washington, D.C., Lou Codispoti, Office of Naval Research, said that scientists have found that there is no immediate regional concern relating to this contamination, although the potential for future concern exists.Bruce Molnia, chief of polar programs at the U.S. Geological Survey, reported on a workshop on Arctic contamination that was held in Anchorage, Alaska, from May 2-7. The workshop was organized by the U.S. Interagency Arctic Research Policy Committee (IARPC), which is made up of fourteen federal agencies that conduct research in the Arctic, in response to Frank Murkowski (R-Alaska) asking what federal agencies would do about contamination in the Arctic. IARPC developed an “agenda for action,” which included the Anchorage workshop.

  8. Membrane potential and cancer progression

    PubMed Central

    Yang, Ming; Brackenbury, William J.

    2013-01-01

    Membrane potential (Vm), the voltage across the plasma membrane, arises because of the presence of different ion channels/transporters with specific ion selectivity and permeability. Vm is a key biophysical signal in non-excitable cells, modulating important cellular activities, such as proliferation and differentiation. Therefore, the multiplicities of various ion channels/transporters expressed on different cells are finely tuned in order to regulate the Vm. It is well-established that cancer cells possess distinct bioelectrical properties. Notably, electrophysiological analyses in many cancer cell types have revealed a depolarized Vm that favors cell proliferation. Ion channels/transporters control cell volume and migration, and emerging data also suggest that the level of Vm has functional roles in cancer cell migration. In addition, hyperpolarization is necessary for stem cell differentiation. For example, both osteogenesis and adipogenesis are hindered in human mesenchymal stem cells (hMSCs) under depolarizing conditions. Therefore, in the context of cancer, membrane depolarization might be important for the emergence and maintenance of cancer stem cells (CSCs), giving rise to sustained tumor growth. This review aims to provide a broad understanding of the Vm as a bioelectrical signal in cancer cells by examining several key types of ion channels that contribute to its regulation. The mechanisms by which Vm regulates cancer cell proliferation, migration, and differentiation will be discussed. In the long term, Vm might be a valuable clinical marker for tumor detection with prognostic value, and could even be artificially modified in order to inhibit tumor growth and metastasis. PMID:23882223

  9. Canonical transient receptor potential 5.

    PubMed

    Beech, D J

    2007-01-01

    Canonical transient receptor potential 5 TRPC5 (also TrpC5, trp-5 or trp5) is one of the seven mammalian TRPC proteins. Its known functional property is that of a mixed cationic plasma membrane channel with calcium permeability. It is active alone or as a heteromultimeric assembly with TRPC1; TRPC4 and TRPC3 may also be involved. Multiple activators of TRPC5 are emerging, including various G protein-coupled receptor agonists, lysophospholipids, lanthanide ions and, in some contexts, calcium store depletion. Intracellular calcium has complex impact on TRPC5, including a permissive role for other activators, as well as inhibition at high concentrations. Protein kinase C is inhibitory and mediates desensitisation following receptor activation. Tonic TRPC5 activity is detected and may reflect the presence of constitutive activation signals. The channel has voltage dependence but the biological significance of this is unknown; it is partially due to intracellular magnesium blockade at aspartic acid residue 633. Protein partners include calmodulin, CaBP1, enkurin, Na(+)-H+ exchange regulatory factor (NHERF) and stathmin. TRPC5 is included in local vesicular trafficking regulated by growth factors through phosphatidylinositol (PI)-3-kinase, Rac1 and PIP-5-kinase. Inhibition of myosin light chain kinase suppresses TRPC5, possibly via an effect on trafficking. Biological roles of TRPC5 are emerging but more reports on this aspect are needed. One proposed role is as a mediator of calcium entry and excitation in smooth muscle, another as an inhibitor of neuronal growth cone extension. The latter is intriguing in view of the original cloning of the human TRPC5 gene from a region of the X chromosome linked to mental retardation. TRPC5 is a broadly expressed calcium channel with capability to act as an integrator of extracellular and intracellular signals at the level of calcium entry. PMID:17217053

  10. The potential of micromagnetic tomography

    NASA Astrophysics Data System (ADS)

    de Groot, Lennart; Béguin, Annemarieke; Fabian, Karl; Reith, Pim; Rastogi, Ankur; Barnhoorn, Auke; Hilgenkamp, Hans

    2016-04-01

    Methods to derive paleodirections or paleointensities from rocks currently rely on measurements of bulk samples (typically ~10 cc). The process of recording and storing magnetizations as function of temperature, however, differs for grains of various sizes and chemical compositions. Most rocks, by their mere nature, consist of assemblages of grains varying in size, shape, and chemistry. When dealing with lavas, this differing magnetic behaviour often hampers paleointensity experiments; while occasionally a reliable paleodirection is obscured (e.g. Coe et al. (2014)). If we would be able to isolate the contribution of each magnetic grain in a sample to the bulk magnetic moment of that sample, a wealth of opportunities for highly detailed magnetic analysis would be opened, possibly leading to an entirely new approach in retrieving paleomagnetic signals from complex mineralogies. Firstly, the distribution and volume of the remanence carrying grains in the sample must be assessed; this is done using a MicroCT scanner capable of detecting grains >1 micron. Secondly, the magnetic stray field perpendicular to the surface of a thin sample is measured using a high-resolution DC SQUID microscope. A mathematical inversion of these measurements yields the isolated direction and magnitude of the magnetic moment of individual grains in the sample. Here we show the results of inversions on a synthetic sample that was magnetised under different angles with respect to the scanned surface. Computational limitations constrain us to inverting only up to tens of grains at the same time. Besides presenting new results of the first successful non-destructive micromagnetic tomography study, we will discuss the current potential and limitations of this technique.

  11. Renewable energy potential in Colombia

    NASA Astrophysics Data System (ADS)

    Correa Guzman, Jose Luis

    2008-12-01

    Renewable energy flows are very large in comparison with humankind's use of energy. In principle, all our energy needs, both now and into the future, can be met by energy from renewable sources. After many years trying to develop the alternative energy potential of Colombia, a major effort is principally being made since 2000 to explore and assess the renewable resources of the entire country. Until 2000, the availability of conventional energy sources in Colombia prevented renewable energy exploration from reaching a higher level. However, the extreme energy crisis of 1992 - 1993 alerted the authorities and the community to the necessity for exploring alternative energy sources. This energy study is a general approach to the current and future renewable energy scenario of Colombia. It was prepared in response to the increased interest around the world and in particular in Colombia to develop its non-fossil energy prospective. It, therefore, represents a working document giving an initial impression of the possible scale of the main renewables sources as a response to the concern about energy security and fossil fuel dependence problems. The assumptions made and calculations reported may therefore be subject to revision as more information becomes available. The aim of this dissertation is not only to improve the public understanding and discussion of renewable energy matters in Colombia but also to stimulate the development and application of renewable energy, wherever they have prospects of economic viability and environmental acceptability. To achieve such goal this paper reviews several renewable technologies, their availability, contribution and feasibility in Colombia.

  12. Potentials in a nonuniform quantum dusty magnetoplasma

    SciTech Connect

    Salimullah, M.; Zeba, I.; Uzma, Ch.; Jamil, M.

    2009-03-15

    Using the quantum hydrodynamic model for quantum magnetoplasmas, the Shukla-Nambu-Salimullah shielding potential and the far-field dynamical wake potential in a quantum dusty plasma with a nonuniform density and ambient static magnetic field have been investigated in detail. The short-range screening potential different from the symmetric Debye-Hueckel potential and the long-range oscillatory wake potential are found to be significantly affected by the nonuniformities in the density and the static magnetic field. The far-field oscillatory wake-field potential can explain attraction among the same polarity charges leading to the possible ordered structures or coagulation in the inhomogeneous quantum dusty magnetoplasma.

  13. Potential energy of a dinuclear system

    SciTech Connect

    Adamyan, G.G.; Antonenko, N.V.; Jolos, R.V.; Ivanova, S.P.; Mel`nikova, O.I.

    1994-11-01

    An effective method for calculating the potential energy of a dinuclear system is proposed. Analytic expressions for calculating the nuclear part of the nucleus-nucleus potential in the double-folding form are obtained. A relationship between this potential and the proximity potential is found. Effects of deformation and mutual orientation of nuclei on the interaction potential are studied. It follows from a comparison of calculated potential energies with nuclear binding energies that excited states of some nuclei can be treated as dinuclear or trinuclear systems. 27 refs., 7 figs.

  14. Photon Physics Potential at ALICE

    NASA Astrophysics Data System (ADS)

    Torii, Hisayuki

    2009-10-01

    The ALICE detector has been designed to study the strongly interacting matter created in nucleus-nucleus collisions at the Large Hadron Collider (LHC). In heavy-ion collisions, it is very critical to measure thermal photons, which are known to carry the temperature information of hot created matter. The thermal photon measurements at RHIC are suggesting the systematic study with better photon detectors at LHC. Furthermore, the suppression of high pT hadrons has provided the first strong signature of hot and dense partonic matter created in heavy-ion collisions at RHIC. Therefore, the suppression behavior of various particle species, including photons, up to LHC energy, is a key observable for the study of the hot matter dynamics. The ALICE PHOton Spectrometer (PHOS) consists of 17920 PWO crystals and Avalanche Photo Diode (APD) covering a rapidity range of ±0.3 and an azimuthal range of 100^o. The fine segment structure and small Moliere radius allow to separate two photons from 0̂ decay at pT=30GeV/c with about 100% efficiency and at even higher pT with smaller efficiency. The decay photons from lower pT 0̂ is the largest background in measuring the thermal photons and can be tagged in a very efficient way with a good energy resolution (3%/√E(GeV)). The ALICE EMCAL consists of shashlik lead-scintillator sampling units covering a rapidity range of ±0.7 and an azimuthal range of 110^ o and sits in the opposite coverage azimuthally to PHOS. The jet measurements by EMCAL and other tracking detectors, especially when tagged by a direct photon in the opposite PHOS detector, represent a key probe for investigating jet quenching effects. In this presentation, physics potential with photon detectors at ALICE during the first physics run of LHC will be discussed. The construction and installation status of the photon detectors as well as their expected physics will be presented.

  15. Therapeutic potential of atmospheric neutrons

    PubMed Central

    Voyant, Cyril; Roustit, Rudy; Tatje, Jennifer; Biffi, Katia; Leschi, Delphine; Briançon, Jérome; Marcovici, Céline Lantieri

    2010-01-01

    Background Glioblastoma multiform (GBM) is the most common and most aggressive type of primary brain tumour in humans. It has a very poor prognosis despite multi-modality treatments consisting of open craniotomy with surgical resection, followed by chemotherapy and/or radiotherapy. Recently, a new treatment has been proposed – Boron Neutron Capture Therapy (BNCT) – which exploits the interaction between Boron-10 atoms (introduced by vector molecules) and low energy neutrons produced by giant accelerators or nuclear reactors. Methods The objective of the present study is to compute the deposited dose using a natural source of neutrons (atmospheric neutrons). For this purpose, Monte Carlo computer simulations were carried out to estimate the dosimetric effects of a natural source of neutrons in the matter, to establish if atmospheric neutrons interact with vector molecules containing Boron-10. Results The doses produced (an average of 1 μGy in a 1 g tumour) are not sufficient for therapeutic treatment of in situ tumours. However, the non-localised yet specific dosimetric properties of 10B vector molecules could prove interesting for the treatment of micro-metastases or as (neo)adjuvant treatment. On a cellular scale, the deposited dose is approximately 0.5 Gy/neutron impact. Conclusion It has been shown that BNCT may be used with a natural source of neutrons, and may potentially be useful for the treatment of micro-metastases. The atmospheric neutron flux is much lower than that utilized during standard NBCT. However the purpose of the proposed study is not to replace the ordinary NBCT but to test if naturally occurring atmospheric neutrons, considered to be an ionizing pollution at the Earth's surface, can be used in the treatment of a disease such as cancer. To finalize this study, it is necessary to quantify the biological effects of the physically deposited dose, taking into account the characteristics of the incident particles (alpha particle and Lithium

  16. Potential risks of pharmacy compounding.

    PubMed

    Gudeman, Jennifer; Jozwiakowski, Michael; Chollet, John; Randell, Michael

    2013-03-01

    Pharmacy compounding involves the preparation of customized medications that are not commercially available for individual patients with specialized medical needs. Traditional pharmacy compounding is appropriate when done on a small scale by pharmacists who prepare the medication based on an individual prescription. However, the regulatory oversight of pharmacy compounding is significantly less rigorous than that required for Food and Drug Administration (FDA)-approved drugs; as such, compounded drugs may pose additional risks to patients. FDA-approved drugs are made and tested in accordance with good manufacturing practice regulations (GMPs), which are federal statutes that govern the production and testing of pharmaceutical products. In contrast, compounded drugs are exempt from GMPs, and testing to assess product quality is inconsistent. Unlike FDA-approved drugs, pharmacy-compounded products are not clinically evaluated for safety or efficacy. In addition, compounded preparations do not have standard product labeling or prescribing information with instructions for safe use. Compounding pharmacies are not required to report adverse events to the FDA, which is mandatory for manufacturers of FDA-regulated medications. Some pharmacies engage in activities that extend beyond the boundaries of traditional pharmacy compounding, such as large-scale production of compounded medications without individual patient prescriptions, compounding drugs that have not been approved for use in the US, and creating copies of FDA-approved drugs. Compounding drugs in the absence of GMPs increases the potential for preparation errors. When compounding is performed on a large scale, such errors may adversely affect many patients. Published reports of independent testing by the FDA, state agencies, and others consistently show that compounded drugs fail to meet specifications at a considerably higher rate than FDA-approved drugs. Compounded sterile preparations pose the additional risk

  17. The Neurotoxic Potential of Engineered Nanomaterials

    EPA Science Inventory

    The expanding development and production of engineered nanomaterials (ENMs) have diverse and far-reaching potential benefits in consumer products, food, drugs, medical devices and for enhancing environmental cleanup and remediation. The knowledge of potential implications of ENMs...

  18. Smokeless Tobacco May Contain Potentially Harmful Bacteria

    MedlinePlus

    ... 160769.html Smokeless Tobacco May Contain Potentially Harmful Bacteria Infections, diarrhea and vomiting are possible consequences, FDA ... products can harbor several species of potentially harmful bacteria, researchers warn. Two types in particular -- Bacillus licheniformis ...

  19. The Potentialities of Man and Anthropomaximology.

    ERIC Educational Resources Information Center

    Kuznetsov, V. V.

    1982-01-01

    Discusses trends in research on human athletic potential. Anthropomaximology, an approach developed in the USSR to study the reserve potential of healthy people and the methods for realizing it under conditions of maximum effort, is described. (AM)

  20. Localization for random and quasiperiodic potentials

    NASA Astrophysics Data System (ADS)

    Spencer, Thomas

    1988-06-01

    A survey is made of some recent mathematical results and techniques for Schrödinger operators with random and quasiperiodic potentials. A new proof of localization for random potentials, established in collaboration with H. von Dreifus, is sketched.

  1. Dexmedetomidine infusion and somatosensory evoked potentials.

    PubMed

    Bloom, M; Beric, A; Bekker, A

    2001-10-01

    Intraoperative neurophysiologic monitoring requires information on the effects of anesthetic drugs because these drugs can directly alter evoked potentials, thus interfering with monitoring. We report on our evaluation of the effect of the recently introduced alpha2-adrenergic agonist, dexmedetomidine, on the somatosensory evoked potentials in two patients undergoing cervico-occipital fusion. Our results suggest that, although dexmedetomidine can affect the later cortical peaks of somatosensory evoked potentials (SSEPs), consistent and reproducible potentials can be recorded. PMID:11733664

  2. Two applications of potential vorticity thinking

    NASA Technical Reports Server (NTRS)

    Robinson, Walter A.

    1987-01-01

    The phenomena of dissipative destabilization of external Rossby waves and the acceleration of the zonal mean jet during baroclinic life cycles are described in terms of potential vorticity. The main principle of the potential temperature variations at rigid boundaries have the same effect on the interior flow as do sheets of potential vorticity located just within the boundaries. It is noted that the potential vorticity theory is useful for understanding the dynamical behavior of meterological phenomena.

  3. Potential Evapotranspiration on Tutuila, American Samoa

    USGS Publications Warehouse

    Izuka, Scott K.; Giambelluca, Thomas W.; Nullet, Michael A.

    2005-01-01

    Data from nine widely distributed climate stations were used to assess the distribution of potential evapotranspiration on the tropical South Pacific island of Tutuila, American Samoa. Seasonal patterns of climate data in this study differed in detail from available long-term data because the monitoring period of each station in this study was only 1 to 5 years, but overall climate conditions during the monitoring period (1999-2004) are representative of normal conditions. Potential evapotranspiration shows a diurnal pattern. On average, potential evapotranspiration in the daytime, when net radiation is the dominant controlling factor, constitutes 90 percent or more of the total daily potential evapotranspiration at each station. Positive heat advection from the ocean contributes to potential evapotranspiration at at least one station, and possibly other stations, in this study. Seasonal variation of potential evapotranspiration is linked to seasonal daylight duration. Spatial variation of potential evapotranspiration, however, is linked primarily to orographic cloud cover. Potential evapotranspiration on Tutuila is lowest in the interior of the island, where rainfall is higher, cloud cover is more frequent, and net radiation is lower than along the coasts. Potential evapotranspiration is highest along the southern and eastern coasts of the island, where rainfall is lower and cloud cover less frequent. The gradient from areas of high to low potential evapotranspiration is steepest in November and December, when island-wide potential evapotranspiration is highest, and less steep in June and July, when island-wide potential evapotranspiration is lowest. Comparison of potential evapotranspiration to rainfall indicates that evapotranspiration processes on Tutuila have the potential to remove from 23 to 61 percent of the water brought by rainfall. In lower-rainfall coastal locations, potential evapotranspiration can be 50 percent or more of rainfall, whereas in higher

  4. Green roofs: potential at LANL

    SciTech Connect

    Pacheco, Elena M

    2009-01-01

    strokes, heat exhaustion, and pollution that can agitate the respiratory system. The most significant savings associated with green roofs is in the reduction of cooling demands due to the green roof's thermal mass and their insulating properties. Unlike a conventional roof system, a green roof does not absorb solar radiation and transfer that heat into the interior of a building. Instead the vegetation acts as a shade barrier and stabilizes the roof temperature so that interior temperatures remain comfortable for the occupants. Consequently there is less of a demand for air conditioning, and thus less money spent on energy. At LANL the potential of green roof systems has already been realized with the construction of the accessible green roof on the Otowi building. To further explore the possibilities and prospective benefits of green roofs though, the initial capital costs must be invested. Three buildings, TA-03-1698, TA-03-0502, and TA-53-0031 have all been identified as sound candidates for a green roof retrofit project. It is recommended that LANL proceed with further analysis of these projects and implementation of the green roofs. Furthermore, it is recommended that an urban forestry program be initiated to provide supplemental support to the environmental goals of green roofs. The obstacles barring green roof construction are most often budgetary and structural concerns. Given proper resources, however, the engineers and design professionals at LANL would surely succeed in the proper implementation of green roof systems so as to optimize their ecological and monetary benefits for the entire organization.

  5. An improved intermolecular potential for sulfur hexafluoride

    SciTech Connect

    Aziz, R.A.; Slaman, M.J. ); Taylor, W.L.; Hurly, J.J. Department of Chemistry, University of Cincinnati, Cincinnati, Ohio 45221 )

    1991-01-15

    Second virial coefficient data and viscosity were used to evaluate effective isotropic intermolecular potential functions proposed in the literature for sulfur hexafluoride. It was found that none of the potentials could predict the properties simultaneously. We have constructed a Morse--Morse--Spline--van der Waals (MMSV) potential which satisfactorily correlates second virial coefficient and viscosity data at the same time.

  6. Nucleon Optical Potential in Brueckner Theory

    SciTech Connect

    Haider, Wasi

    2008-10-13

    Recent results of g-matrix calculation of the nucleon optical potential are presented and their predictions are compared with experimental data for Sn-isotopes. Corrections to spin-orbit part of the potential are discussed. Extension of Bethe's method to calculate three nucleon interaction effects in the nucleon optical potential is presented.

  7. Generic scalar potentials in geometric scalar gravity

    NASA Astrophysics Data System (ADS)

    Kan, Nahomi; Shiraishi, Kiyoshi

    2016-06-01

    We discuss a generic form of the scalar potential appearing in the geometric scalar theory of gravity. We find the conditions on the potential by considering weak and strong gravity. The modified black hole solutions are obtained for generic potentials and the inverse problems on a black hole and on a spherical body (`pseudo-gravastar') are investigated.

  8. Classification of geothermal resources by potential

    NASA Astrophysics Data System (ADS)

    Rybach, L.

    2015-03-01

    When considering and reporting resources, the term "geothermal potential" is often used without clearly stating what kind of potential is meant. For renewable energy resources it is nowadays common to use different potentials: theoretical, technical, economic, sustainable, developable - decreasing successively in size. In such a sequence, the potentials are progressively realizable and more and more rewarding financially. The theoretical potential describes the physically present energy, the technical potential the fraction of this energy that can be used by currently available technology and the economic potential the time- and location-dependent fraction of the previous category; the sustainable potential constrains the fraction of the economic potential that can be utilized in the long term; the developable potential is the fraction of the economic resource which can be developed under realistic conditions. In converting theoretical to technical potential, the recovery factor (the ratio extractable heat/heat present at depth) is of key importance. An example (global geothermal resources) is given, with numerical values of the various potentials. The proposed classification could and should be used as a kind of general template for future geothermal energy resources reporting.

  9. Modeling International Space Station (ISS) Floating Potentials

    NASA Technical Reports Server (NTRS)

    Ferguson, Dale C.; Gardner, Barbara

    2002-01-01

    The floating potential of the International Space Station (ISS) as a function of the electron current collection of its high voltage solar array panels is derived analytically. Based on Floating Potential Probe (FPP) measurements of the ISS potential and ambient plasma characteristics, it is shown that the ISS floating potential is a strong function of the electron temperature of the surrounding plasma. While the ISS floating potential has so far not attained the pre-flight predicted highly negative values, it is shown that for future mission builds, ISS must continue to provide two-fault tolerant arc-hazard protection for astronauts on EVA.

  10. Relationship between supersymmetry and solvable potentials

    NASA Astrophysics Data System (ADS)

    Cooper, Fred; Ginocchio, Joseph N.; Khare, Avinash

    1987-10-01

    We investigate whether a general class of solvable potentials, the Natanzon potentials (those potentials whose solutions are hypergeometric functions), and their supersymmetric partner potentials are related by a discrete reparametrization invariance called ``shape invariance'' discovered by Genden- shtein. We present evidence that this is not the case in general. Instead we find that the Natanzon class of potentials is not the most general class of solvable potentials but instead belongs to a wider class of potentials generated by supersymmetry and factorization whose eigenfunctions are sums of hypergeometric functions. The series of Hamiltonians, together with the corresponding supersymmetric charges form the graded Lie algebra sl(1/1)⊗SU(2). We also present a strategy for solving, in a limited domain, the discrete reparametrization invariance equations connected with ``shape invariance.''

  11. Potential: the valuation of imagined future achievement.

    PubMed

    Andrew Poehlman, T; Newman, George E

    2014-01-01

    The concept of potential is central to a number of decisions, ranging from organizational hiring, to athletic recruiting, to the evaluation of artistic performances. While potential may often be valued for its future payoffs, the present studies investigate whether people value potential even when making decisions about goods and experiences that can only be consumed in the present. Experiment 1 demonstrates that potential makes people more likely to consume inferior performances in the present. Experiment 2 manipulated temporal focus and demonstrates that focusing on the present (vs. the future) attenuates the effect of potential on enjoyment. Experiment 3 demonstrates that merely moving the performance into the past negates the effect of potential. And, Experiment 4 demonstrates that potential increases valuation only when value is tied to abstract, hedonic dimensions, but not when it is tied to concrete, utilitarian dimensions. PMID:24225186

  12. Thermodynamics of anisotropic fluids using isotropic potentials

    SciTech Connect

    Bastea, S; Ree, F H

    1999-08-16

    We study the effectiveness and limitations of the median potential recipe for mixtures such as N{sub 2} + O{sub 2} and N{sub 2} + CO{sub 2}, that are important in detonation applications. Conversely, we treat effective spherical potentials extracted from Hugoniot experiments (e.g., N{sub 2} and O{sub 2}) as median potentials and invert them to extract atom-atom potentials. The resulting non-spherical potentials compare remarkably well with the atom - atom potentials used in studies of solid state properties. Finally, we propose a method to improve the median potential for stronger anisotropic fluids such as CO{sub 2} and its mixtures.

  13. Potential wells for classical acoustic waves

    NASA Astrophysics Data System (ADS)

    Chen, Shi; Lin, ShuYu; Mo, RunYang; Fu, ZhiQiang

    2014-01-01

    The acceleration theorem of Bloch waves is utilized to construct random potential wells for classical acoustic waves in systems composed of alternating `cavities' and `couplers'. One prominent advantage of this method is these `cavities' and `couplers' are all monolayer structures. It allows forming more compact classical potential wells, which leads to the miniaturization of acoustic devices. We systematically investigate properties of harmonic, tangent, hyperbolic function, and square classical potential wells in quasi-periodic superlattices. Results show these classical potential wells are analogues of quantum potential wells. Thus some technologies and concepts in quantum potential well fields may be generalized to classical acoustic wave fields. In addition, some abnormal cases regarding forming classical potential wells are also found.

  14. Indoor radon risk potential of Hawaii

    USGS Publications Warehouse

    Reimer, G.M.; Szarzi, S.L.

    2005-01-01

    A comprehensive evaluation of radon risk potential in the State of Hawaii indicates that the potential for Hawaii is low. Using a combination of factors including geology, soils, source-rock type, soil-gas radon concentrations, and indoor measurements throughout the state, a general model was developed that permits prediction for various regions in Hawaii. For the nearly 3,100 counties in the coterminous U.S., National Uranium Resource Evaluation (NURE) aerorad data was the primary input factor. However, NURE aerorad data was not collected in Hawaii, therefore, this study used geology and soil type as the primary and secondary components of potential prediction. Although the radon potential of some Hawaiian soils suggests moderate risk, most houses are built above ground level and the radon soil potential is effectively decoupled from the house. Only underground facilities or those with closed or recirculating ventilation systems might have elevated radon potential. ?? 2005 Akade??miai Kiado??.

  15. Pumped Storage and Potential Hydropower from Conduits

    SciTech Connect

    none,

    2015-02-25

    Th is Congressional Report, Pumped Storage Hydropower and Potential Hydropower from Conduits, addresses the technical flexibility that existing pumped storage facilities can provide to support intermittent renewable energy generation. This study considered potential upgrades or retrofit of these facilities, the technical potential of existing and new pumped storage facilities to provide grid reliability benefits, and the range of conduit hydropower opportunities available in the United States.

  16. Potential flow through centrifugal pumps and turbines

    NASA Technical Reports Server (NTRS)

    Sorensen, E

    1941-01-01

    The methods of conformal transformation up to the present have been applied to the potential flows in the rotation of solid bodies only to a limited extent. This report deals with aspects of centrifugal pumps and turbines such as: the complex potential for rotation, potential for the flow due to the blade rotation, velocities at the blade tip, comparison with "infinite number of blades," and a variable number of blades.

  17. Potential radiation doses from 1994 Hanford Operations

    SciTech Connect

    Soldat, J.K.; Antonio, E.J.

    1995-06-01

    This section of the 1994 Hanford Site Environmental Report summarizes the potential radiation doses to the public from releases originating at the Hanford Site. Members of the public are potentially exposed to low-levels of radiation from these effluents through a variety of pathways. The potential radiation doses to the public were calculated for the hypothetical MEI and for the general public residing within 80 km (50 mi) of the Hanford Site.

  18. Understanding Vertical Jump Potentiation: A Deterministic Model.

    PubMed

    Suchomel, Timothy J; Lamont, Hugh S; Moir, Gavin L

    2016-06-01

    This review article discusses previous postactivation potentiation (PAP) literature and provides a deterministic model for vertical jump (i.e., squat jump, countermovement jump, and drop/depth jump) potentiation. There are a number of factors that must be considered when designing an effective strength-power potentiation complex (SPPC) focused on vertical jump potentiation. Sport scientists and practitioners must consider the characteristics of the subject being tested and the design of the SPPC itself. Subject characteristics that must be considered when designing an SPPC focused on vertical jump potentiation include the individual's relative strength, sex, muscle characteristics, neuromuscular characteristics, current fatigue state, and training background. Aspects of the SPPC that must be considered for vertical jump potentiation include the potentiating exercise, level and rate of muscle activation, volume load completed, the ballistic or non-ballistic nature of the potentiating exercise, and the rest interval(s) used following the potentiating exercise. Sport scientists and practitioners should design and seek SPPCs that are practical in nature regarding the equipment needed and the rest interval required for a potentiated performance. If practitioners would like to incorporate PAP as a training tool, they must take the athlete training time restrictions into account as a number of previous SPPCs have been shown to require long rest periods before potentiation can be realized. Thus, practitioners should seek SPPCs that may be effectively implemented in training and that do not require excessive rest intervals that may take away from valuable training time. Practitioners may decrease the necessary time needed to realize potentiation by improving their subject's relative strength. PMID:26712510

  19. Membrane potential generated by ion adsorption.

    PubMed

    Tamagawa, Hirohisa; Morita, Sachi

    2014-01-01

    It has been widely acknowledged that the Goldman-Hodgkin-Katz (GHK) equation fully explains membrane potential behavior. The fundamental facet of the GHK equation lies in its consideration of permeability of membrane to ions, when the membrane serves as a separator for separating two electrolytic solutions. The GHK equation describes that: variation of membrane permeability to ion in accordance with ion species results in the variation of the membrane potential. However, nonzero potential was observed even across the impermeable membrane (or separator) separating two electrolytic solutions. It gave rise to a question concerning the validity of the GHK equation for explaining the membrane potential generation. In this work, an alternative theory was proposed. It is the adsorption theory. The adsorption theory attributes the membrane potential generation to the ion adsorption onto the membrane (or separator) surface not to the ion passage through the membrane (or separator). The computationally obtained potential behavior based on the adsorption theory was in good agreement with the experimentally observed potential whether the membrane (or separator) was permeable to ions or not. It was strongly speculated that the membrane potential origin could lie primarily in the ion adsorption on the membrane (or separator) rather than the membrane permeability to ions. It might be necessary to reconsider the origin of membrane potential which has been so far believed explicable by the GHK equation. PMID:24957176

  20. Shape invariant potentials in higher dimensions

    SciTech Connect

    Sandhya, R.; Sree Ranjani, S.; Kapoor, A.K.

    2015-08-15

    In this paper we investigate the shape invariance property of a potential in one dimension. We show that a simple ansatz allows us to reconstruct all the known shape invariant potentials in one dimension. This ansatz can be easily extended to arrive at a large class of new shape invariant potentials in arbitrary dimensions. A reformulation of the shape invariance property and possible generalizations are proposed. These may lead to an important extension of the shape invariance property to Hamiltonians that are related to standard potential problems via space time transformations, which are found useful in path integral formulation of quantum mechanics.

  1. Exact string potential and heavy quarkonia

    SciTech Connect

    Bambah, B.A. ); Dharamvir, K.; Kaur, R. ); Sharma, A.C. )

    1992-03-01

    Using the exact form of the static string potential we reinvestigate previous potential-model calculations of the energy levels of {ital q{bar q}} resonances. We show the effect of higher-order corrections to strings on the quarkonium spectroscopy and the leptonic decays of the {Upsilon} and {ital J}/{psi}, where we find that the roughened form of the string potential has a significant effect. We also propose a new form of the potential which incorporates both the quantum effects and asymptotic freedom.

  2. Geology, potential of Argentina's international bidding areas

    SciTech Connect

    Pucci, J.C. , Buenos Aires )

    1994-06-13

    Argentina, in terms of the exploration/production potential involved, has opened three types of areas to the international industry: (1) areas of secondary interest (marginal fields); (2) Yacimientos Petroliferos Fiscales SA's (YPF) central fields; and (3) exploitation and exploration association contract areas. The areas differ by the oil and gas potential included in each, the resultant contract terms, and the difference in risk involved in exploitation versus exploration targets. In this article, specific areas and fields are discussed, especially the oil and gas potential as expressed by past production, remaining reserves, and future potential.

  3. Membrane Potential Generated by Ion Adsorption

    PubMed Central

    Tamagawa, Hirohisa; Morita, Sachi

    2014-01-01

    It has been widely acknowledged that the Goldman-Hodgkin-Katz (GHK) equation fully explains membrane potential behavior. The fundamental facet of the GHK equation lies in its consideration of permeability of membrane to ions, when the membrane serves as a separator for separating two electrolytic solutions. The GHK equation describes that: variation of membrane permeability to ion in accordance with ion species results in the variation of the membrane potential. However, nonzero potential was observed even across the impermeable membrane (or separator) separating two electrolytic solutions. It gave rise to a question concerning the validity of the GHK equation for explaining the membrane potential generation. In this work, an alternative theory was proposed. It is the adsorption theory. The adsorption theory attributes the membrane potential generation to the ion adsorption onto the membrane (or separator) surface not to the ion passage through the membrane (or separator). The computationally obtained potential behavior based on the adsorption theory was in good agreement with the experimentally observed potential whether the membrane (or separator) was permeable to ions or not. It was strongly speculated that the membrane potential origin could lie primarily in the ion adsorption on the membrane (or separator) rather than the membrane permeability to ions. It might be necessary to reconsider the origin of membrane potential which has been so far believed explicable by the GHK equation. PMID:24957176

  4. On the ionization potential of molecular oxygen

    NASA Technical Reports Server (NTRS)

    Samson, J. A. R.; Gardner, J. L.

    1974-01-01

    The ionization potential of O2 was measured by the technique of high resolution photoelectron spectroscopy taking into account the influence of rotational structure on the shape of the vibrational bands. A value of 12.071 + or - .001 eV (1027.1 + or - 0.1 A) was found for the ionization potential. A lowering of the ionization potential caused by a branch-head when delta N = -2 gave an appearance potential for ionization of 12.068 + or - .001 eV (1027.4 + or - 0.1 A).

  5. Exam Question Exchange: Potential Energy Surfaces.

    ERIC Educational Resources Information Center

    Alexander, John J., Ed.

    1988-01-01

    Presents three examination questions, graded in difficulty, that explore the topic of potential energy surfaces using a diagrammatic approach. Provides and discusses acceptable solutions including diagrams. (CW)

  6. A Be-W interatomic potential.

    PubMed

    Björkas, C; Henriksson, K O E; Probst, M; Nordlund, K

    2010-09-01

    In this work, an interatomic potential for the beryllium-tungsten system is derived. It is the final piece of a potential puzzle, now containing all possible interactions between the fusion reactor materials beryllium, tungsten and carbon as well as the plasma hydrogen isotopes. The potential is suitable for plasma-wall interaction simulations and can describe the intermetallic Be(2)W and Be(12)W phases. The interaction energy between a Be surface and a W atom, and vice versa, agrees qualitatively with ab initio calculations. The potential can also reasonably describe Be(x)W(y) molecules with x, y = 1, 2, 3, 4. PMID:21403279

  7. Response of potential probes to nonequilibrium situations

    NASA Astrophysics Data System (ADS)

    Manifacier, J.-C.; Moreau, Y.; Henisch, H. K.; Rieder, G.

    1984-07-01

    When a metal contact is placed on a semiconducting material which is not in electronic equilibrium, a floating potential (difference) is developed between the metal and the bulk semiconductor. This is analogous to the open circuit voltage of a solar cell. Floating potentials can cause substantial errors when associated with probes used for the determination of potential contours. Their magnitude is here calculated by numerical and analytic techniques, as a function of the departure from equilibrium and the characteristics of the contact barrier structure. Criteria are established for a safe use of potential probes.

  8. Feasibility of streaming potential measurements during hydrofracturing

    SciTech Connect

    Wurmstich, B.; Buettgenbach, T.; Morgan, F.D.

    1995-12-31

    A simple model study shows that the onset of hydraulic fracturing and eventually fracture directions may be detected in streaming potential measurements. To model streaming potential responses of hydraulic fracturing, a theory of slowly time-varying electrokinetic phenomena and a self-consistent model to describe rock conductivities in terms of intrinsic rock properties are developed. Measureable streaming potential responses are generated during the hydraulic fracturing process. The fracturing process amplifies the observable streaming potential response by up to one order of magnitude when compared to a similar experiment without fracturing. The resolution of fractures is better in monitoring wells than on the surface.

  9. Chloroplast Response to Low Leaf Water Potentials

    PubMed Central

    Keck, R. W.; Boyer, J. S.

    1974-01-01

    Cyclic and noncyclic photophosphorylation and electron transport by photosystem 1, photosystem 2, and from water to methyl viologen (“whole chain”) were studied in chloroplasts isolated from sunflower (Helianthus annus L. var Russian Mammoth) leaves that had been desiccated to varying degrees. Electron transport showed considerable inhibition at leaf water potentials of −9 bars when the chloroplasts were exposed to an uncoupler in vitro, and it continued to decline in activity as leaf water potentials decreased. Electron transport by photosystem 2 and coupled electron transport by photosystem 1 and the whole chain were unaffected at leaf water potentials of −10 to −11 bars but became progressively inhibited between leaf water potentials of −11 and −17 bars. A low, stable activity remained at leaf water potentials below −17 bars. In contrast, both types of photophosphorylation were unaffected by leaf water potentials of −10 to −11 bars, but then ultimately became zero at leaf water potentials of −17 bars. Although the chloroplasts isolated from the desiccated leaves were coupled at leaf water potentials of −11 to −12 bars, they became progressively uncoupled as leaf water potentials decreased to −17 bars. Abscisic acid and ribonuclease had no effect on chloroplast photophosphorylation. The results are generally consistent with the idea that chloroplast activity begins to decrease at the same leaf water potentials that cause stomatal closure in sunflower leaves and that chloroplast electron transport begins to limit photosynthesis at leaf water potentials below about −11 bars. However, it suggests that, during severe desiccation, the limitation may shift from electron transport to photophosphorylation. PMID:16658727

  10. Chemical Potentials and Activities: An Electrochemical Introduction.

    ERIC Educational Resources Information Center

    Wetzel, T. L.; And Others

    1986-01-01

    Describes a laboratory experiment which explores the effects of adding inert salts to electrolytic cells and demonstrates the difference between concentration and chemical activity. Examines chemical potentials as the driving force of reactions. Provides five examples of cell potential and concentration change. (JM)

  11. Mining the Potential in Your State Standards

    ERIC Educational Resources Information Center

    Breault, Rick

    2014-01-01

    State and national standards, taken as is, can limit the potential of the curriculum and skilled teachers. The ideas presented here suggest ways in which we might better scrutinize standards for their potential richness and limitations in order to enrich our instruction.

  12. Some aspects of three-quark potentials

    NASA Astrophysics Data System (ADS)

    Andreev, Oleg

    2016-05-01

    We analytically evaluate the expectation value of a baryonic Wilson loop in a holographic model of an S U (3 ) pure gauge theory. We then discuss three aspects of a static three-quark potential: an aspect of universality which concerns properties independent of a geometric configuration of quarks, a heavy diquark structure, and a relation between the three- and two-quark potentials.

  13. On solvable Dirac equation with polynomial potentials

    SciTech Connect

    Stachowiak, Tomasz

    2011-01-15

    One-dimensional Dirac equation is analyzed with regard to the existence of exact (or closed-form) solutions for polynomial potentials. The notion of Liouvillian functions is used to define solvability, and it is shown that except for the linear potentials the equation in question is not solvable.

  14. The Potential of Statement-Posing Tasks

    ERIC Educational Resources Information Center

    Yang, Kai-Lin

    2010-01-01

    This communication aims at revealing the potential of statement-posing tasks to facilitate students' thinking and strategies of understanding proof. Besides outlining the background of statement-posing tasks, four points were advanced as potential benefits of the tasks: (1) focusing on the logic of arguments in addition to the meaning of…

  15. Human Potential Education and Public Schooling.

    ERIC Educational Resources Information Center

    Fletcher, Jerry L.

    The human potential movement the encourages growth beyond the conventional definitions of a normal or successful life. This movement is entering into a new phase characterized by carefully integrated sequences of the best human potential exercises, put together in a program that enables individuals to take a deep, personal look at their lives.…

  16. Fuel production potential of several agricultural crops

    SciTech Connect

    Mays, D.A.; Buchanan, W.; Bradford, B.N.

    1984-11-01

    Data collected on starch and sugar crops indicate that sweet potato and sweet sorghum have the best potential for alcohol production in the TVA area. Of the oil crops evaluated in this series of experiments only sunflower and okara appear to offer potential in the Tennessee Valley for oil production for fuel or other uses. 21 tabs.

  17. Potentials of Rubella Deaf-Blind Children.

    ERIC Educational Resources Information Center

    Smith, Benjamin F.

    Potentials of three classifications of rubella deaf blind children are discussed. Potentials for children at the middle trainable level and below are discussed for the areas of communication skills, daily living skills, mobility and orientation, vocational effort, and self-control and social interaction. For children in the upper trainable through…

  18. Petroleum source rock potential on Jamaica

    SciTech Connect

    Rodrigues, K.

    1983-01-10

    By means of standard geochemical techniques, geologists evaluated the hydrocarbon source rock potential of Jamaican shales and mudstones in terms of the amount, type, and maturity of the organic matter preserved in these sediments. Samples taken from outcrops and well cores revealed that shales from the Chapelton and Windsor formations may have the best potential for hydrocarbon generation.

  19. State and Local Revenue Potential 1969.

    ERIC Educational Resources Information Center

    Quindry, Kenneth E.

    This report contains the results of an extensive study into State and local tax revenue potentials for the 15 Southern Regional Education Board (SREB) States. It identifies, on a State-by-State basis, both the degree of current use and the potential for increased use of (1) general and selective sales and gross receipts taxes, (2) death and gift…

  20. EVOKED POTENTIALS, PHYSIOLOGICAL METHODS WITH HUMAN APPLICATIONS

    EPA Science Inventory

    A number of tests and test batteries have been developed and implemented for detecting potential neurotoxicity in humans. n some cases test results may suggest specific dysfunction. hile tests in laboratory animals are often used to project the potential for adverse health effect...

  1. YouTube: Educational Potentials and Pitfalls

    ERIC Educational Resources Information Center

    Jones, Troy; Cuthrell, Kristen

    2011-01-01

    The instructional potential of video technology in the classroom is promising, especially in light of the 21st Century Learning Framework (Siegle, 2009). Studies show positive gains in student outcomes as a result of the integration of video technology in instruction. This article explores potential uses of YouTube as an instructional aid in…

  2. On the Generalized Potential of Inertial Forces

    ERIC Educational Resources Information Center

    Siboni, S.

    2009-01-01

    The generalized potential of the inertial forces acting on a holonomic system in an accelerated reference frame is derived in a way which admits a simple physical interpretation. It is shown that the generalized potential refers to all the inertial forces and, apart from the very special case of a uniformly rotating frame, it is impossible to…

  3. Nonconical Relaxation for Supersonic Potential Flow

    NASA Technical Reports Server (NTRS)

    Siclari, M. J.

    1986-01-01

    Nonlinear, three-dimensional effects computed from full potentialflow equation. Nonconical Relaxation program, NCOREL, employs new computational technique for prediction of inviscid, nonlinear supersonic aerodynamics. Unlike conventional linear potential equations, NCOREL utilizes full potential flow equation to predict formation of supercritical crossflow regions, embedded shocks, and bow shocks. NCOREL written in FORTRAN IV for batch execution.

  4. Resonances for Symmetric Two-Barrier Potentials

    ERIC Educational Resources Information Center

    Fernandez, Francisco M.

    2011-01-01

    We describe a method for the accurate calculation of bound-state and resonance energies for one-dimensional potentials. We calculate the shape resonances for symmetric two-barrier potentials and compare them with those coming from the Siegert approximation, the complex scaling method and the box-stabilization method. A comparison of the…

  5. USE OF SENSORY EVOKED POTENTIALS IN TOXICOLOGY

    EPA Science Inventory

    The rationale for studying sensory systems as an integral part of neurotoxicological examinations is presented. The role of evoked potentials in assessing brain dysfunction in general and sensory systems in particular is also presented. Four types of sensory evoked potentials (br...

  6. Theoretical studies of potential energy surfaces

    SciTech Connect

    Harding, L.B.

    1995-07-01

    MRCI (configuration interaction) calculations were used to examine possible pathways for the O{sub 2} + CCH reaction. The H{sub 2} + CN potential surface was examined. An initial survey was made of the HCl + CN potential energy surface at a low level of theory.

  7. Getting the Best Estimate of Learning Potential.

    ERIC Educational Resources Information Center

    Berliner, David; Casanova, Ursula

    1988-01-01

    Two researchers present perspectives on the types of assessments teachers should conduct to obtain the best possible expectations for student potential and achievement. Suggestions are also presented regarding ways to help students reach their potential and to continue assessing and revising expectations. (CB)

  8. Integrability of Hamiltonian systems with algebraic potentials

    NASA Astrophysics Data System (ADS)

    Maciejewski, Andrzej J.; Przybylska, Maria

    2016-01-01

    Problem of integrability for Hamiltonian systems with potentials that are algebraic thus multivalued functions of coordinates is discussed. Introducing potential as a new variable the original Hamiltonian system on 2n dimensional phase space is extended to 2 n + 1 dimensional system with rational right-hand sides. For extended system its non-canonical degenerated Poisson structure of constant rank 2n and rational Hamiltonian is identified. For algebraic homogeneous potentials of non-zero rational homogeneity degree necessary integrability conditions are formulated. These conditions are deduced from an analysis of the differential Galois group of variational equations around particular solutions of a straight line type. Obtained integrability obstructions are applied to the class of monomial homogeneous potentials. Some integrable potentials satisfying these conditions are found.

  9. Potential evaluation in soil-side environments

    SciTech Connect

    Chmilar, J.F.; Holtsbaum, W.B. )

    1994-03-01

    The traditional method for determining the status of cathodic protection (CP) for underground pipelines is by measuring pipe-electrolyte (pipe-to-soil) potentials. In the past, this measurement often was assumed to be a pure DC voltage because the reading between the reference electrode and the structure was steady when measured by a galvanometer-type instrument. Many pipelines now are recognized to be under the influence of a variety of potential sources in addition to that from CP rectifiers. An understanding of these potentials is necessary. The average'' DC pipe-electrolyte potential, the actual waveform from an oscilloscope measurement in field applications, and their uses in the measurement of instant-off polarized potentials are addressed.

  10. Spacecraft potential control on ISEE-1

    NASA Technical Reports Server (NTRS)

    Gonfalone, A.; Pedersen, A.; Fahleson, U. V.; Faelthammar, C. G.; Mozer, F. S.; Torbert, R. B.

    1979-01-01

    Active control of the potential of the ISEE-1 satellite by the use of electron guns is reviewed. The electron guns contain a special cathode capable of emitting an electron current selectable between 10 to the -8th power and 10 to the -3rd power at energies from approximately .6 to 41 eV. Results obtained during flight show that the satellite potential can be stabilized at a value more positive than the normally positive floating potential. The electron guns also reduce the spin modulation of the spacecraft potential which is due to the aspect dependent photoemission of the long booms. Plasma parameters like electron temperature and density can be deduced from the variation of the spacecraft potential as a function of the gun current. The effects of electron beam emission on other experiments are briefly mentioned.

  11. QCD sign problem for small chemical potential

    SciTech Connect

    Splittorff, K.; Verbaarschot, J. J. M.

    2007-06-01

    The expectation value of the complex phase factor of the fermion determinant is computed in the microscopic domain of QCD at nonzero chemical potential. We find that the average phase factor is nonvanishing below a critical value of the chemical potential equal to half the pion mass and vanishes exponentially in the volume for larger values of the chemical potential. This holds for QCD with dynamical quarks as well as for quenched and phase quenched QCD. The average phase factor has an essential singularity for zero chemical potential and cannot be obtained by analytic continuation from imaginary chemical potential or by means of a Taylor expansion. The leading order correction in the p-expansion of the chiral Lagrangian is calculated as well.

  12. Simple Exercises to Flatten your Potential

    SciTech Connect

    Dong, Xi; Horn, Bart; Silverstein, Eva; Westphal, Alexander; /DESY /SLAC

    2011-08-12

    We show how backreaction of the inflaton potential energy on heavy scalar fields can flatten the inflationary potential, as the heavy fields adjust to their most energetically favorable configuration. This mechanism operates in previous UV-complete examples of axion monodromy inflation - flattening a would-be quadratic potential to one linear in the inflaton field - but occurs more generally, and we illustrate the effect with several examples. Special choices of compactification minimizing backreaction may realize chaotic inflation with a quadratic potential, but we argue that a flatter potential such as power-law inflation V({phi}) {proportional_to} {phi}{sup p} with p < 2 is a more generic option at sufficiently large values of {phi}.

  13. Transonic Flow Computations Using Nonlinear Potential Methods

    NASA Technical Reports Server (NTRS)

    Holst, Terry L.; Kwak, Dochan (Technical Monitor)

    2000-01-01

    This presentation describes the state of transonic flow simulation using nonlinear potential methods for external aerodynamic applications. The presentation begins with a review of the various potential equation forms (with emphasis on the full potential equation) and includes a discussion of pertinent mathematical characteristics and all derivation assumptions. Impact of the derivation assumptions on simulation accuracy, especially with respect to shock wave capture, is discussed. Key characteristics of all numerical algorithm types used for solving nonlinear potential equations, including steady, unsteady, space marching, and design methods, are described. Both spatial discretization and iteration scheme characteristics are examined. Numerical results for various aerodynamic applications are included throughout the presentation to highlight key discussion points. The presentation ends with concluding remarks and recommendations for future work. Overall. nonlinear potential solvers are efficient, highly developed and routinely used in the aerodynamic design environment for cruise conditions. Published by Elsevier Science Ltd. All rights reserved.

  14. [The disposing techniques of evoked potentials].

    PubMed

    Liu, H G; Zhou, L; Gu, J; Jing, D Z

    2000-11-01

    This paper is to bring forward the new disposing techniques of evoked potentials which include four aspect techniques of the averaging, the recording, digital sampling and filters about the averaging, evoked potential amplitude, evoked potential latency, evoked potential recording, and evoked potential generations. The technique of the averaging including signal filtering and a periodic averaging, can enhance EP dedection. The commercial EP machines also plot changes in latency between serial EP studies in order to detect trends in peak latency. The modern digital EP recording device consists of sensory stimator, recording amplifiers with analog filters, an analog-to-digital converter, a digital signal averager, and a display and storage system. A sample-and-hold function is one of the recent developments which used EP collectors that provide simultaneous recording with multiple channels employing different time and voltage scales and sampling rates. The EP data may be further processed following A-D conversion by digital filters. PMID:12583248

  15. Potential energy studies on silane dimers

    NASA Astrophysics Data System (ADS)

    Mahlanen, Riina; Pakkanen, Tapani A.

    2011-04-01

    Intermolecular interactions and parameters for use in MD studies of large molecule systems have earlier been determined for hydrocarbons, carbon tetrahalides and sulfur. The paper reports a model representing nonbonding interactions between silane molecules, which were examined in the same way as hydrocarbons in an earlier (neopentane, isopropane, propane, and ethane) study. Intermolecular potentials were determined for 11 combinations of silane compound pairs (silane SiH 4, disilane Si 2H 6, trisilane Si 3H 8, isotetrasilane Si 4H 10 and neopentasilane Si 5H 12) with MP2/aug(df)-6-311G ∗ab initio calculations. The most stable dimer configurations were identified. With use of the modified Morse potential model to represent the interactions, 276 new potential energy surfaces were generated for silane dimers. Separate and generic pair potentials were calculated for the silanes. The pair potentials can be used in MD studies of silanes.

  16. Sequential colour mapping system of brain potentials.

    PubMed

    Giard, M H; Peronnet, F; Pernier, J; Mauguiere, F; Bertrand, O

    1985-05-01

    We present a colour mapping system for the visualization of both the spatial scalp distribution and the temporal evolution of brain potentials. The system is applicable to recordings of auditory, visual and somatosensory potentials. It uses a Tektronix 4113 colour terminal connected to a Solar 16 (SEMS) mini-computer. The brain potentials are recorded on up to 16 scalp electrodes. The gain and the baseline are corrected separately on each channel. At each point of the scalp the potential is reconstructed by a linear interpolation of the measured potentials of the four nearest electrodes. Simultaneously n2 (1 less than n less than 8) colour maps can be presented on the screen. This allows the study of the temporal evolution of full scalp evoked potentials. The user chooses the two extreme latencies defining the time window to be explored and the latencies of the maps are regularly time-spaced within this window. In a typical case, in which four maps are desired, the latencies of the maps can be chosen independently. The 16-colour palette is predetermined but the user has three possibilities to establish the correspondence between the electrical potential and the colours. Examples are shown in the visual and somatosensory stimulation modalities. The advantages and limitations of such a representation are discussed. PMID:3849381

  17. Dirac Green function for angular projection potentials.

    PubMed

    Zeller, Rudolf

    2015-11-25

    The aim of this paper is twofold: first, it is shown that the angular dependence of the Dirac Green function can be described analytically for potentials with non-local dependence on the angular variables if they are chosen as projection potentials in angular momentum space. Because the local dependence on the radial variable can be treated to any precision with present computing capabilities, this means that the Green function can be calculated practically exactly. Second, it is shown that a result of this kind not only holds for a single angular projection potential but also more generally, for instance if space is divided into non-overlapping cells and a separate angular projection potential is used in each cell. This opens the way for relativistic density-functional calculations within a different perspective than the conventional one. Instead of trying to obtain the density for a given potential approximately as well as possible, the density is determined exactly for non-local potentials which can approximate arbitrary local potentials as well as desired. PMID:26523824

  18. Potential interactions between alternative therapies and warfarin.

    PubMed

    Heck, A M; DeWitt, B A; Lukes, A L

    2000-07-01

    Potential and documented interactions between alternative therapy agents and warfarin are discussed. An estimated one third of adults in the United States use alternative therapies, including herbs. A major safety concern is potential interactions of alternative medicine products with prescription medications. This issue is especially important with respect to drugs with narrow therapeutic indexes, such as warfarin. Herbal products that may potentially increase the risk of bleeding or potentiate the effects of warfarin therapy include angelica root, arnica flower, anise, asafoetida, bogbean, borage seed oil, bromelain, capsicum, celery, chamomile, clove, fenugreek, feverfew, garlic, ginger ginkgo, horse chestnut, licorice root, lovage root, meadowsweet, onion, parsley, passionflower herb, poplar, quassia, red clover, rue, sweet clover, turmeric, and willow bark. Products that have been associated with documented reports of potential interactions with warfarin include coenzyme Q10, danshen, devil's claw, dong quai, ginseng, green tea, papain, and vitamin E. Interpretation of the available information on herb-warfarin interactions is difficult because nearly all of it is based on in vitro data, animal studies, or individual case reports. More study is needed to confirm and assess the clinical significance of these potential interactions. There is evidence that a wide range of alternative therapy products have the potential to interact with warfarin. Pharmacists and other health care professionals should question all patients about use of alternative therapies and report documented interactions to FDA's MedWatch program. PMID:10902065

  19. On locally and nonlocally related potential systems

    NASA Astrophysics Data System (ADS)

    Cheviakov, Alexei F.; Bluman, George W.

    2010-07-01

    For any partial differential equation (PDE) system, a local conservation law yields potential equations in terms of some potential variable, which normally is a nonlocal variable. The current paper examines situations when such a potential variable is a local variable, i.e., is a function of the independent and dependent variables of a given PDE system, and their derivatives. In the case of two independent variables, a simple necessary and sufficient condition is presented for the locality of such a potential variable, and this is illustrated by several examples. As a particular example, two-dimensional reductions of equilibrium equations for fluid and plasma dynamics are considered. It is shown that such reductions with respect to helical, axial, and translational symmetries have conservation laws which yield local potential variables. This leads to showing that the well-known Johnson-Frieman-Kruskal-Oberman (JFKO) and Bragg-Hawthorne (Grad-Shafranov) equations are locally related to the corresponding helically and axially symmetric PDE systems of fluid/plasma dynamics. For the axially symmetric case, local symmetry classifications and arising invariant solutions are compared for the original PDE system and the Bragg-Hawthorne (potential) equation. The potential equation is shown to have additional symmetries, denoted as restricted symmetries. Restricted symmetries leave invariant a family of solutions of a given PDE system but not the whole solution manifold, and hence are not symmetries of the given PDE system. Corresponding reductions are shown to yield solutions, which are not obtained as invariant solutions from local symmetry reduction.

  20. Dirac Green function for angular projection potentials

    NASA Astrophysics Data System (ADS)

    Zeller, Rudolf

    2015-11-01

    The aim of this paper is twofold: first, it is shown that the angular dependence of the Dirac Green function can be described analytically for potentials with non-local dependence on the angular variables if they are chosen as projection potentials in angular momentum space. Because the local dependence on the radial variable can be treated to any precision with present computing capabilities, this means that the Green function can be calculated practically exactly. Second, it is shown that a result of this kind not only holds for a single angular projection potential but also more generally, for instance if space is divided into non-overlapping cells and a separate angular projection potential is used in each cell. This opens the way for relativistic density-functional calculations within a different perspective than the conventional one. Instead of trying to obtain the density for a given potential approximately as well as possible, the density is determined exactly for non-local potentials which can approximate arbitrary local potentials as well as desired.

  1. Electrostatic Potential Across Supercritical Collisionless Shock

    NASA Astrophysics Data System (ADS)

    Khotyaintsev, Y. V.; Vaivads, A.; Krasnoselskikh, V.

    2013-12-01

    Using multi-spacecraft Cluster observations of the Earth's bow shock we estimate the electrostatic potential across a supercritical quasi-perpendicular collisionless shock. We find the potential values of the order of several kV, which correspond roughly to the kinetic energy of the inflowing solar wind. It is expected that the plasma flow in the de Hoffmann-Teller frame is field-aligned, and thus the potential computed in this frame is the parallel potential experienced by both ions and electrons. Contrary to this expectation, we show that most of the potential computed in the de Hoffmann-Teller frame is contributed by sub-proton scale Hall electric field, E~JxB/ne, which exists due to decoupling of electron and ion motions at such small scales (ions are demagnetized, and electrons are still well magnetized), and therefore the electron motion in such field is perpendicular to B. In order to calculate the parallel potential drop experienced by electrons, one needs to go to the 'electron' Hoffmann-Teller frame at small scales, in which the JxB/ne field is zero. In this 'electron' frame we find much smaller values of the potential drop across the shock of the order of 100 eV, which is comparable to the change of electron temperature across the shock, and is in agreement with theoretical estimates.

  2. Cellular Functions of Transient Receptor Potential channels

    PubMed Central

    Dadon, Daniela; Minke, Baruch

    2010-01-01

    Transient Receptor Potential channels are polymodal cellular sensors involved in a wide variety of cellular processes, mainly by increasing cellular Ca2+. In this review we focus on the roles of these channels in: i) cell death ii) proliferation and differentiation and iii) synaptic vesicle release. Cell death Ca2+ influx participates in apoptotic and necrotic cell death. The Ca2+ permeability and high sensitivity of part of these channels to oxidative/metabolic stress make them important participants in cell death. Several examples are given. Transient Receptor Potential Melastatin 2 is activated by H2O2, inducing cell death through an increase in cellular Ca2+ and activation of Poly ADP-Ribose Polymerase. Exposure of cultured cortical neurons to oxygen-glucose deprivation, in vitro, causes cell death via cation influx, mediated by Transient Receptor Potential Melastatin 7. Metabolic stress constitutively activates the Ca2+ permeable Transient Receptor Potential channels of Drosophila photoreceptor in the dark, potentially leading to retinal degeneration. Similar sensitivity to metabolic stress characterizes several mammalian Transient Receptor Potential Canonical channels. Proliferation and differentiation The rise in cytosolic Ca2+ induces cell growth, differentiation and proliferation via activation of several transcription factors. Activation a variety of store operated and Transient Receptor Potential channels cause a rise in cytosolic Ca2+, making these channels components involved in proliferation and differentiation. Synaptic vesicle release Transient Receptor Potential Melastatin 7 channels reside in synaptic vesicles and regulate neurotransmitter release by a mechanism that is not entirely clear. All the above features of Transient Receptor Potential channels make them crucial components in important, sometimes conflicting, cellular processes that still need to be explored. PMID:20399884

  3. Ion potential diagrams for electrochromic devices

    SciTech Connect

    Varsano, F. |; Cahen, D.; Decker, F.; Guillemoles, J.F. |; Masetti, E.

    1998-12-01

    Ion potential diagrams can facilitate the description of systems in which ionic species are mobile. They depict qualitatively the spatial dependence of the potential energy for mobile ions, somewhat akin to band diagrams for electrons. The authors construct ion potential diagrams for the mixed conducting (oxide), optically active electrodes of five-layer electrochromic devices, based on reversible Li{sup +} intercalation. These serve to analyze stability problems that arise in these systems. The authors then use them as building blocks to arrive at ion diagrams for complete devices. This allows analyses of (dis)coloration kinetics.

  4. Radion effective potential in brane gas cosmology

    SciTech Connect

    Kim, Jin Young

    2008-09-15

    We consider a cosmological solution which can explain anisotropic evolution of spatial dimensions and the stabilization of extra dimensions in brane gas formalism. We evaluate the effective potentials, induced by brane gas, bulk flux and supergravity particles, which govern the sizes of the observed three and the extra dimensions. It is possible that the wrapped internal volume can oscillate between two turning points or sit at the minimum of the potential while the unwrapped three-dimensional volume can expand monotonically. Including the supergravity particles makes the effective potential steeper as the internal volume shrinks.

  5. Stretching the inflaton potential with kinetic energy

    SciTech Connect

    Lidsey, James E.

    2007-08-15

    Inflation near a maximum of the potential is studied when nonlocal derivative operators are included in the inflaton Lagrangian. Such terms can impose additional sources of friction on the field. For an arbitrary spacetime geometry, these effects can be quantified in terms of a local field theory with a potential whose curvature around the turning point is strongly suppressed. This implies that a prolonged phase of slow-roll inflation can be achieved with potentials that are otherwise too steep to drive quasiexponential expansion. We illustrate this mechanism within the context of p-adic string theory.

  6. Adiabatic Hyperspherical Analysis of Realistic Nuclear Potentials

    NASA Astrophysics Data System (ADS)

    Daily, K. M.; Kievsky, Alejandro; Greene, Chris H.

    2015-12-01

    Using the hyperspherical adiabatic method with the realistic nuclear potentials Argonne V14, Argonne V18, and Argonne V18 with the Urbana IX three-body potential, we calculate the adiabatic potentials and the triton bound state energies. We find that a discrete variable representation with the slow variable discretization method along the hyperradial degree of freedom results in energies consistent with the literature. However, using a Laguerre basis results in missing energy, even when extrapolated to an infinite number of basis functions and channels. We do not include the isospin T = 3/2 contribution in our analysis.

  7. Electrostatic patch potentials in Casimir force measurements

    NASA Astrophysics Data System (ADS)

    Garrett, Joseph; Somers, David; Munday, Jeremy

    2015-03-01

    Measurements of the Casimir force require the elimination of the electrostatic force between interacting surfaces. The force can be minimized by applying a potential to one of the two surfaces. However, electrostatic patch potentials remain and contribute an additional force which can obscure the Casimir force signal. We will discuss recent measurements of patch potentials made with Heterodyne Amplitude-Modulated Kelvin Probe Force Microscopy that suggest patches could be responsible for >1% of the signal in some Casimir force measurements, and thus make the distinction between different theoretical models of the Casimir force (e.g. a Drude-model or a plasma-model for the dielectric response) difficult to discern.

  8. Thermochromic behaviors and ionization potentials of organopolysilanes

    NASA Astrophysics Data System (ADS)

    Yokoyama, Kenji; Yokoyama, Masaaki

    1989-04-01

    Ionization potentials of organopolysilanes with different kinds of substituents were evaluated from the low energy photo-electron emission measurements in air. An aryl-substituted organopolysilane capable of σ - π mixing between Si backbone σ and side-group π electrons gave smaller ionization potential by about 0.1˜0.15 eV compared with alkyl-substituted organopolysilanes. The value of ionization potentials in some alkyl-substituted organopolysilanes which showed thermochromic behaviors was found to vary substantially with thermally induced reversible changes in polymer backbone conformation, indicating that the effective conjugation length of σ electrons decreases above the thermochromic transition temperature.

  9. A highly accurate interatomic potential for argon

    NASA Astrophysics Data System (ADS)

    Aziz, Ronald A.

    1993-09-01

    A modified potential based on the individually damped model of Douketis, Scoles, Marchetti, Zen, and Thakkar [J. Chem. Phys. 76, 3057 (1982)] is presented which fits, within experimental error, the accurate ultraviolet (UV) vibration-rotation spectrum of argon determined by UV laser absorption spectroscopy by Herman, LaRocque, and Stoicheff [J. Chem. Phys. 89, 4535 (1988)]. Other literature potentials fail to do so. The potential also is shown to predict a large number of other properties and is probably the most accurate characterization of the argon interaction constructed to date.

  10. Arabian plate hydrocarbon geology and potential

    SciTech Connect

    Beydoun, Z.R.

    1991-01-01

    This book provides a thought-provoking, succinct presentation of the geologic evolution and hydrocarbon potential of the world's most prolific petroleum province. The fascinating subjects discussed and documented include: What are the unique geologic factors that make the Middle East such a prolific province Where are the future Mesozoic and Tertiary plays What is the virtually untapped potential of the Paleozoic section What are the play potentials for underexplored areas such as Jordan, Syria, Yemen How are deeper drilling results shaping and modifying concepts of the Arabian plate history and pointing the way to future hydrocarbon targets

  11. Bond order potential module for LAMMPS

    SciTech Connect

    2012-09-11

    pair_bop is a module for performing energy calculations using the Bond Order Potential (BOP) for use in the parallel molecular dynamics code LAMMPS. The bop pair style computes BOP based upon quantum mechanical incorporating both sigma and pi bondings. By analytically deriving the BOP pair bop from quantum mechanical theory its transferability to different phases can approach that of quantum mechanical methods. This potential is extremely effective at modeling 111-V and II-VI compounds such as GaAs and CdTe. This potential is similar to the original BOP developed by Pettifor and later updated by Murdock et al. and Ward et al.

  12. Elaboration of a water ichtyologic potential index.

    PubMed

    Dehavay, P; Boelen, C

    1992-04-01

    A model has been developed, using physico-chemical data, in order to quantify the quality of surface waters and their ichtyologic potential: the WIPI model (Water Ichtyologic Potential Index). Many physico-chemical parameters, useless if considered individually, can be of practical interest for pisciculture (e.g., an explanation of systematic fish mortalities, elaboration of guidelines for new pisciculture). The water quality is expressed in terms of an eight-step scale that provides a guide evaluation of the ichtyologic potential. PMID:1594921

  13. I-ball formation with logarithmic potential

    SciTech Connect

    Kawasaki, Masahiro; Takeda, Naoyuki E-mail: takedan@icrr.u-tokyo.ac.jp

    2014-07-01

    A coherently oscillating real scalar field with potential shallower than quadratic one fragments into spherical objects called I-balls. We study the I-ball formation for logarithmic potential which appears in many cosmological models. We perform lattice simulations and find that the I-balls are formed when the potential becomes dominated by the quadratic term. Furthermore, we estimate the I-ball profile assuming that the adiabatic invariant is conserved during formation and obtain the result that agrees to the numerical simulations.

  14. Potentiation of morphine analgesia by caffeine.

    PubMed Central

    Misra, A. L.; Pontani, R. B.; Vadlamani, N. L.

    1985-01-01

    Significant potentiation of morphine (5 mg kg-1 s.c. or 1 mg kg-1 i.v.) analgesia (tail-withdrawal reflex at 55 degrees C) was observed in caffeine-treated (100 mg kg-1 i.p.) rats as compared to the control group and lower doses of caffeine (2mg kg-1 i.p.) did not show this effect. Potentiated analgesia was reversed by naloxone. Pharmacokinetic or dispositional factors appear to be involved in part in this potentiation. PMID:4005485

  15. Potentiation of morphine analgesia by caffeine.

    PubMed

    Misra, A L; Pontani, R B; Vadlamani, N L

    1985-04-01

    Significant potentiation of morphine (5 mg kg-1 s.c. or 1 mg kg-1 i.v.) analgesia (tail-withdrawal reflex at 55 degrees C) was observed in caffeine-treated (100 mg kg-1 i.p.) rats as compared to the control group and lower doses of caffeine (2mg kg-1 i.p.) did not show this effect. Potentiated analgesia was reversed by naloxone. Pharmacokinetic or dispositional factors appear to be involved in part in this potentiation. PMID:4005485

  16. Wave Energy Potential in the Latvian EEZ

    NASA Astrophysics Data System (ADS)

    Beriņš, J.; Beriņš, J.; Kalnačs, J.; Kalnačs, A.

    2016-06-01

    The present article deals with one of the alternative forms of energy - sea wave energy potential in the Latvian Exclusice Economic Zone (EEZ). Results have been achieved using a new method - VEVPP. Calculations have been performed using the data on wave parameters over the past five years (2010-2014). We have also considered wave energy potential in the Gulf of Riga. The conclusions have been drawn on the recommended methodology for the sea wave potential and power calculations for wave-power plant pre-design stage.

  17. Potential of renewable and alternative energy sources

    NASA Astrophysics Data System (ADS)

    Konovalov, V.; Pogharnitskaya, O.; Rostovshchikova, A.; Matveenko, I.

    2015-11-01

    The article deals with application potential of clean alternative renewable energy sources. By means of system analysis the forecast for consumption of electrical energy in Tomsk Oblast as well as main energy sources of existing energy system have been studied up to 2018. Engineering potential of renewable and alternative energy sources is evaluated. Besides, ranking in the order of their efficiency descending is performed. It is concluded that Tomsk Oblast has high potential of alternative and renewable energy sources, among which the most promising development perspective is implementation of gasification stations to save fuel consumed by diesel power stations as well as building wind-power plants.

  18. Static quark potential in three flavor QCD

    SciTech Connect

    Bernard, Claude; Burch, Tom; Orginos, Kostas; Toussaint, Doug; DeGrand, Thomas A.; DeTar, Carleton; Gottlieb, Steven; Heller, Urs M.; Hetrick, James E.; Sugar, Bob

    2000-08-01

    We study the effects of dynamical quarks on the static quark potential at distances shorter than those where string breaking is expected. Quenched calculations and calculations with three flavors of dynamical quarks are done on sets of lattices with the lattice spacings matched within about one percent. The effect of the sea quarks on the shape of the potential is clearly visible. We investigate the consequences of these effects in a very crude model, namely solving Schroedinger's equation in the resulting potential. (c) 2000 The American Physical Society.

  19. POTENTIAL USE OF ULTRASOUND IN CHEMICAL MONITORING

    EPA Science Inventory

    The U.S. Environmental Protection Agency has been examining the potential of combining sonication with existing measurement technologies for monitoring specific classes of organic pollutants in water. he research specifically addressed using ultrasound (ultrasonic) processors to ...

  20. Abraham Maslow: On the Potential of Women

    ERIC Educational Resources Information Center

    Podeschi, Ronald L.; Podeschi, Phyllis J.

    1973-01-01

    Authors presented some principal perspectives by the psychologist, Abraham Maslow, who died in 1970, and who was writing about the potential of women long before it became popular to do so. (Author/RK)

  1. Potentials for transverse trace-free tensors

    NASA Astrophysics Data System (ADS)

    Conboye, Rory; Murchadha, Niall Ó.

    2014-04-01

    In constructing and understanding initial conditions in the 3 + 1 formalism for numerical relativity, the transverse and trace-free (TT) part of the extrinsic curvature plays a key role. We know that TT tensors possess two degrees of freedom per space point. However, finding an expression for a TT tensor depending on only two scalar functions is a non-trivial task. Assuming either axial or translational symmetry, expressions depending on two scalar potentials alone are derived here for all TT tensors in flat 3-space. In a more general spatial slice, only one of these potentials is found, the same potential given in (Baker and Puzio 1999 Phys. Rev. D 59 044030) and (Dain 2001 Phys. Rev. D 64 124002), with the remaining equations reduced to a partial differential equation, depending on boundary conditions for a solution. As an exercise, we also derive the potentials which give the Bowen-York curvature tensor in flat space.

  2. Varying potential silicon carbide gas sensor

    NASA Technical Reports Server (NTRS)

    Shields, Virgil B. (Inventor); Ryan, Margaret A. (Inventor); Williams, Roger M. (Inventor)

    1997-01-01

    A hydrocarbon gas detection device operates by dissociating or electro-chemically oxidizing hydrocarbons adsorbed to a silicon carbide detection layer. Dissociation or oxidation are driven by a varying potential applied to the detection layer. Different hydrocarbon species undergo reaction at different applied potentials so that the device is able to discriminate among various hydrocarbon species. The device can operate at temperatures between 100.degree. C. and at least 650.degree. C., allowing hydrocarbon detection in hot exhaust gases. The dissociation reaction is detected either as a change in a capacitor or, preferably, as a change of current flow through an FET which incorporates the silicon carbide detection layers. The silicon carbide detection layer can be augmented with a pad of catalytic material which provides a signal without an applied potential. Comparisons between the catalytically produced signal and the varying potential produced signal may further help identify the hydrocarbon present.

  3. Probiotics as potential antioxidants: a systematic review.

    PubMed

    Mishra, Vijendra; Shah, Chandni; Mokashe, Narendra; Chavan, Rupesh; Yadav, Hariom; Prajapati, Jashbhai

    2015-04-15

    Probiotics are known for their health beneficial effects and are established as dietary adjuncts. Probiotics have been known for many beneficial health effects. In this view, there is interest to find the potential probiotic strains that can exhibit antioxidant properties along with health benefits. In vitro and in vivo studies indicate that probiotics exhibit antioxidant potential. In this view, consumption of probiotics alone or foods supplemented with probiotics may reduce oxidative damage, free radical scavenging rate, and modification in activity of crucial antioxidative enzymes in human cells. Incorporation of probiotics in foods can provide a good strategy to supply dietary antioxidants, but more studies are needed to standardize methods and evaluate antioxidant properties of probiotics before they can be recommended for antioxidant potential. In this paper, the literature related to known antioxidant potential of probiotics and proposing future perspectives to conduct such studies has been reviewed. PMID:25808285

  4. Potential Hazards of Plastics Used in Sculpture

    ERIC Educational Resources Information Center

    Siedlecke, Jerome T.

    1972-01-01

    This paper discusses the thermoplastic and thermosetting resins presently being used by the artist, and the potential for exposure to the toxic chemicals and other hazards during the development of his creative work. (Author)

  5. Potential Optimization Software for Materials (POSMat)

    NASA Astrophysics Data System (ADS)

    Martinez, Jackelyn A.; Chernatynskiy, Aleksandr; Yilmaz, Dundar E.; Liang, Tao; Sinnott, Susan B.; Phillpot, Simon R.

    2016-06-01

    The Potential Optimization Software for Materials package (POSMat) is presented. POSMat is a powerful tool for the optimization of classical empirical interatomic potentials for use in atomic scale simulations, of which molecular dynamics is the most ubiquitous. Descriptions of the empirical formalisms and targetable properties available are given. POSMat includes multiple tools, including schemes and strategies to aid in the optimization process. Samples of the inputs and outputs are given as well as an example for fitting an MgO Buckingham potential, which illustrates how the targeted properties can influence the results of a developed potential. Approaches and tools for the expansion of POSMat to other interatomic descriptions and optimization algorithms are described.

  6. Remarks on the Woods-Saxon potential

    NASA Astrophysics Data System (ADS)

    Çapak, M.; Gönül, B.

    2016-06-01

    More recently, comprehensive applications of approximate analytical solutions of the Woods-Saxon (WS) potential in closed form for the five-dimensional Bohr Hamiltonian have appeared [M. Çapak, D. Petrellis, B. Gönül and D. Bonatsos, J. Phys. G 42, 95102 (2015)] and its comparison to the data for many different nuclei has clearly revealed the domains for the success and failure in case of using such potential forms to analyze the data related to the nuclear structure within the frame of the collective model. Gaining confidence from this work, the exact solvability of the WS type potentials in lower dimensions for the bound states having zero angular momentum is carefully reviewed to finalize an ongoing discussion in the related literature which clearly shows that such kind of potentials have no analytical solutions even for ℓ = 0 case.

  7. Liquid membrane potential in nonisothermal systems.

    PubMed Central

    Scibona, G; Fabiani, C; Scuppa, B; Danesi, P R

    1976-01-01

    Electrical membrane potential equations for liquid ion exchange membranes, characterized by the presence of uncharged associated species and by exclusion of co-ions (no electrolyte uptake) have been derived. The irreversible thermodynamic theories already developed for solid membranes with fixed charged site density have been extended to include the different physicochemical aspects of the liquid membranes. To this purpose the dissipation function has been written with reference to the fluxes of all the species present in the membrane. It has been found that the mobile charged site, the counterions, and the uncharged associated species contribute to the electrical membrane potential through their phenomenological coefficients. The electrical membrane potential equations have been integrated in isothermal and nonisothermal conditions for monoionic and biionic systems. The theoretical predictions have been experimentally tested by studying the electrical potential of liquid membranes formed with solutions of tetraheptylammonium salts in omicron-dichlorobenzene. PMID:1276391

  8. The onset of plasma potential locking

    NASA Astrophysics Data System (ADS)

    Hopkins, Matthew M.; Yee, Benjamin T.; Baalrud, Scott D.; Barnat, Edward V.

    2016-06-01

    In this paper, we provide insight into the role and impact that a positively biased electrode (anode) has on bulk plasma potential. Using two-dimensional Particle-in-Cell simulations, we investigate the plasma potential as an anode transitions from very small ("probe" mode) to large ("locking" mode). Prior theory provides some guidance on when and how this transition takes place. Initial experimental results are also compared. The simulations demonstrate that as the surface area of the anode is increased transitions in plasma potential and sheath polarity occur, consistent with experimental observations and theoretical predictions. It is expected that understanding this basic plasma behavior will be of interest to basic plasma physics communities, diagnostic developers, and plasma processing devices where control of bulk plasma potential is important.

  9. Riemann zeros, prime numbers, and fractal potentials.

    PubMed

    van Zyl, Brandon P; Hutchinson, David A W

    2003-06-01

    Using two distinct inversion techniques, the local one-dimensional potentials for the Riemann zeros and prime number sequence are reconstructed. We establish that both inversion techniques, when applied to the same set of levels, lead to the same fractal potential. This provides numerical evidence that the potential obtained by inversion of a set of energy levels is unique in one dimension. We also investigate the fractal properties of the reconstructed potentials and estimate the fractal dimensions to be D=1.5 for the Riemann zeros and D=1.8 for the prime numbers. This result is somewhat surprising since the nearest-neighbor spacings of the Riemann zeros are known to be chaotically distributed, whereas the primes obey almost Poissonlike statistics. Our findings show that the fractal dimension is dependent on both level statistics and spectral rigidity, Delta(3), of the energy levels. PMID:16241330

  10. Potential Evaporation in North America Through 2100

    NASA Video Gallery

    This animation shows the projected increase in potential evaporation through the year 2100, relative to 1980, based on the combined results of multiple climate models. The maximum increase across N...

  11. Missing solution in a Cornell potential

    NASA Astrophysics Data System (ADS)

    Castro, L. B.; de Castro, A. S.

    2013-11-01

    Missing bound-state solutions for fermions in the background of a Cornell potential consisting of a mixed scalar-vector-pseudoscalar coupling is examined. Charge-conjugation operation, degeneracy and localization are discussed.

  12. Waveguide BEC Interferometry with Painted Potentials

    NASA Astrophysics Data System (ADS)

    Boshier, Malcolm; Lebedev, Vyacheslav; Samson, Carlo; Ryu, Changhyun

    2015-05-01

    Waveguide atom interferometers offer the possibility of long measurement times in a compact geometry, which can be an advantage over free space interferometers if the dephasing due to interatomic interactions can be controlled. We are investigating waveguide BEC interferometers created with the painted potential, a technique which allows for the creation and manipulation of BECs in arbitrary 2D potentials. The goal is to measure a linear acceleration of the device. The painted potential allows new approaches to the initial splitting of the BEC. For example, instead of smoothly deforming a single well potential into a double well, it is possible instead to gradually remove a weak link coupling two initially separated waveguides. This strategy should reduce excitations created in the splitting process. We are currently implementing such schemes and measuring the coherence time of the BEC after division. We will present the results of these measurements, and report progress towards measuring linear accelerations. Supported by LANL/LDRD.

  13. Ozone depletion and chlorine loading potentials

    NASA Technical Reports Server (NTRS)

    Pyle, John A.; Wuebbles, Donald J.; Solomon, Susan; Zvenigorodsky, Sergei; Connell, Peter; Ko, Malcolm K. W.; Fisher, Donald A.; Stordal, Frode; Weisenstein, Debra

    1991-01-01

    The recognition of the roles of chlorine and bromine compounds in ozone depletion has led to the regulation or their source gases. Some source gases are expected to be more damaging to the ozone layer than others, so that scientific guidance regarding their relative impacts is needed for regulatory purposes. Parameters used for this purpose include the steady-state and time-dependent chlorine loading potential (CLP) and the ozone depletion potential (ODP). Chlorine loading potentials depend upon the estimated value and accuracy of atmospheric lifetimes and are subject to significant (approximately 20-50 percent) uncertainties for many gases. Ozone depletion potentials depend on the same factors, as well as the evaluation of the release of reactive chlorine and bromine from each source gas and corresponding ozone destruction within the stratosphere.

  14. Potential Health Effects from Groundwater Pollution.

    ERIC Educational Resources Information Center

    Goyer, Robert A.

    1985-01-01

    Discusses the growing awareness of potential toxicological effects of synthetic organic chemicals contaminating groundwater. Problems concerning pesticides, chlorination, epidemiologic studies, cancer, nephrotoxicity, and considerations of risk are addressed. Additional research in this area is advocated. (DH)

  15. TRMM Animation of Flood Potential from Haiyan

    NASA Video Gallery

    TRMM animation of flood potential from Nov. 2 to Nov. 12 shows the movement of Tropical Storm 30W, Typhoon Krosa and Super-Typhoon Hainan. Yellow is low, orange is medium, and red is high. Credit: ...

  16. SAMPLING AND ANALYSIS OF POTENTIAL GEOTHERMAL SITES

    EPA Science Inventory

    This document contains general information on the physical, chemical and radiochemical data of geothermal manifestations (wells and springs) in areas with the most probable potential for development. Information contained in this document, together with other existing data, can b...

  17. Estimating potential evapotranspiration with improved radiation estimation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Potential evapotranspiration (PET) is of great importance to estimation of surface energy budget and water balance calculation. The accurate estimation of PET will facilitate efficient irrigation scheduling, drainage design, and other agricultural and meteorological applications. However, accuracy o...

  18. The Encyclopedia of Chemical Electrode Potentials

    SciTech Connect

    Antelman, M.S.

    1982-01-01

    Designed for industrial chemists concerned with chemical potential data in their day-to-day performance of experiments, The Encyclopedia of Chemical Electrode Potentials is the most comprehensive listing of chemical electrode potentials available today, including dat derived from many different reports, articles, and tabulations, and also previously unpublished complex formation EMF data. Thermodynamic calculations based on data reflecting varying conditions have made it possible to integrate results obtained at different pressures and electrolyte concentrations into a useful electromotive series. The electrochemical series which constitutes the core of the Encyclopedia embodies a novel arrangement which differentiates between anions, cations, complexes, and compounds. For the convenience of the practicing chemist, the data are made accessible in a number of different ways: all the information in the electrochemical series is reorganized into a listing of electrode potentials by element.

  19. Potential targets for lung squamous cell carcinoma

    Cancer.gov

    Researchers have identified potential therapeutic targets in lung squamous cell carcinoma, the second most common form of lung cancer. The Cancer Genome Atlas (TCGA) Research Network study comprehensively characterized the lung squamous cell carcinoma gen

  20. {sup 4}He microscopic optical model potential

    SciTech Connect

    Guo Hairui; Liang Haiying; Han Yinlu; Shen Qingbiao; Xu Yongli

    2011-06-15

    The {sup 4}He microscopic optical model potential is obtained by Green's function method through nuclear matter approximation and local density approximation based on the effective Skyrme interaction. The microscopic optical model potential is analyzed and utilized to calculate the reaction cross sections and elastic scattering angular distributions for the target nuclei in the mass range 12{<=}A{<=}209 with incident {sup 4}He energy up to 400 MeV. The theoretical results are compared with the experimental data.

  1. Collisional relaxation in a nonintegrable potential

    NASA Astrophysics Data System (ADS)

    Kandrup, H. E.; Willmes, D. E.

    1994-03-01

    In galactic dynamics, a test star is assumed typically to follow a smooth trajectory in some slowly varying mean field potential and, in addition, to be subjected to 'random' close encounters with neighboring field stars which are modeled essentially as a Brownian process. With the noteable exception of Pfenniger (1986), most analyses of the collisonal relaxation induced by these close encounters have assumed that the effects of the mean field may be ignored completely, and that it suffices to consider Brownian particles moving in the absence of any systematic potential. The idealization of zero potential is problematic, as is any integrable potential in which all the mean field orbits are stable. For this reason, the paradigm of Brownian motion is reexamined here, allowing for a time-dependent, non-integrable potential, in which some subset of the mean field trajectories correspond to exponentially unstable orbits with positive Liapounov exponent. A nontrivial deterministic equation of motion is convereted into a stochastic differential equation incorporating dynamical friction and delta-correlated white noise, related via a fluctuation-dissipation theorem, and the effects of the friction and noise are analyzed perturbatively. The principal conclusion is that a coupling to a nonintegrable background potential can decrease by orders of magnitude the time scale on which noise and friction modify positions and velocities along an unperturbed, deterministic trajectory. Specifically, one finds that, even in the weak noise limit, perturbations in position and velocity grow exponentially on a time scale tlambda determined by the Liapounov exponent, although, for a strictly time-dependent potential, perturbations in energy and other collisionless invariants will only grow on a much longer relaxation time tr. Some potential implications of this accelerated collisional relaxation are discussed.

  2. Surface potential profiles. [for electrocardiographic data processing

    NASA Technical Reports Server (NTRS)

    Sharp, J. K.; Jones, W. P., Jr.

    1974-01-01

    The gathering of surface potential profiles by computerized processing of electrocardiogram data is projected. These profiles are concerned with the detail of localized potentials on the human body and are obtained by voltages plotted against electrode positions with time as the variable held constant. Sample and hold circuits are considered for processing the multiplexed signal and to digitize and code it for the tape recorder.

  3. BB Potentials in Quenched Lattice QCD

    SciTech Connect

    William Detmold; Kostas Orginos; Martin J. Savage

    2007-12-01

    The potentials between two B-mesons are computed in the heavy-quark limit using quenched lattice QCD at $m_\\pi\\sim 400~{\\rm MeV}$. Non-zero central potentials are clearly evident in all four spin-isospin channels, (I,s_l) = (0,0) , (0,1) , (1,0) , (1,1), where s_l is the total spin of the light degrees of freedom. At short distance, we find repulsion in the $I\

  4. Molecular electrostatic potentials by systematic molecular fragmentation

    SciTech Connect

    Reid, David M.; Collins, Michael A.

    2013-11-14

    A simple method is presented for estimating the molecular electrostatic potential in and around molecules using systematic molecular fragmentation. This approach estimates the potential directly from the electron density. The accuracy of the method is established for a set of organic molecules and ions. The utility of the approach is demonstrated by estimating the binding energy of a water molecule in an internal cavity in the protein ubiquitin.

  5. Membrane potential changes during chemokinesis in Paramecium.

    PubMed

    Van Houten, J

    1979-06-01

    Intracellular recordings show that (i) paramecia hyperpolarize slightly in attractants and depolarize in repellents that depend on the avoiding reaction (an abrupt change of swimming direction), and (ii) paramecia more strongly hyperpolarize in repellents and more strongly depolarize in attractants that depend on changes of swimming velocity. These membrane potential changes are in agreement with a hypothesis of membrane potential control of chemokinesis in Paramecium. PMID:572085

  6. Potential vorticity formulation of compressible magnetohydrodynamics.

    PubMed

    Arter, Wayne

    2013-01-01

    Compressible ideal magnetohydrodynamics is formulated in terms of the time evolution of potential vorticity and magnetic flux per unit mass using a compact Lie bracket notation. It is demonstrated that this simplifies analytic solution in at least one very important situation relevant to magnetic fusion experiments. Potentially important implications for analytic and numerical modelling of both laboratory and astrophysical plasmas are also discussed. PMID:23383802

  7. The potential uses of operational earthquake forecasting

    USGS Publications Warehouse

    Field, Ned; Jordan, Thomas; Jones, Lucille; Michael, Andrew; Blanpied, Michael L.

    2016-01-01

    This article reports on a workshop held to explore the potential uses of operational earthquake forecasting (OEF). We discuss the current status of OEF in the United States and elsewhere, the types of products that could be generated, the various potential users and uses of OEF, and the need for carefully crafted communication protocols. Although operationalization challenges remain, there was clear consensus among the stakeholders at the workshop that OEF could be useful.

  8. The skin sensitization potential of four alkylalkanolamines.

    PubMed

    Leung, H W; Blaszcak, D L

    1998-04-01

    The skin sensitization potential of 4 alkylalkanolamines (N-methylethanolamine, N,N-dimethylethanolamine, N-methyldiethanolamine and N,N-diethylethanolamine), was evaluated in a guinea pig maximation procedure by the method of Magnusson and Kligman. While all 4 alkylalkanolamines tested were irritating to the guinea pig skin, only N-methylethanolamine showed potential to induce allergic contact dermatitis. None of the remaining 3 alkylalkanolamines exhibited clear skin responses suggestive of sensitization. PMID:9554055

  9. Dirac particle in a pseudoscalar potential

    SciTech Connect

    Moreno, Matias; Zentella-Dehesa, Arturo

    1996-02-20

    We study the problem of a Dirac particle with a pseudoscalar interaction in the potential approximation. It is shown how nonperturbative relativistic solutions arise. The case of the central pseudoscalar potential is explicitly worked out also in a closed form. The angular functions are worked out in general for this central case. Finally for the special case of the spherical well the radial solutions are shown to behave like Bessel-type functions.

  10. Dirac particle in a pseudoscalar potential

    SciTech Connect

    Moreno, M.; Zentella-Dehesa, A.

    1996-02-01

    We study the problem of a Dirac particle with a pseudoscalar interaction in the potential approximation. It is shown how nonperturbative relativistic solutions arise. The case of the central pseudoscalar potential is explicitly worked out also in a closed form. The angular functions are worked out in general for this central case. Finally for the special case of the spherical well the radial solutions are shown to behave like Bessel-type functions. {copyright} {ital 1996 American Institute of Physics.}

  11. Perturbation Theory for Superfluid in Nonuniform Potential

    NASA Astrophysics Data System (ADS)

    Koshida, Shinji; Kato, Yusuke

    2016-05-01

    Perturbation theory of superfluid fraction in terms of nonuniform potential is constructed. We find that the coefficient of the leading term is determined by the dynamical structure factor or density fluctuation of the system. The results for the ideal Bose gas and the interacting Bose system with linear dispersion are consistent to implications from Landau's criterion. We also find that the superfluidity of Tomonaga-Luttinger liquid with K>2 is shown to be stable against nonuniform potential.

  12. Electrostatic potential fluctuations in a Maxwellian plasma

    SciTech Connect

    Hazeltine, R.D.; Lowrey, J.D.

    2006-01-15

    The spatial correlation function of a Maxwellian plasma with perturbations arising in the electrostatic potential due to random ion density fluctuations is examined. The entropy is found from the one-particle distribution function using the Shannon formula and then, using the Einstein method, the probability distribution for the electrostatic potential fluctuation is determined. This straightforward procedure is demonstrated to be a powerful tool in studying plasma correlation functions when the system entropy can be computed.

  13. Analytical second derivatives for effective core potentials

    NASA Astrophysics Data System (ADS)

    Breidung, Jürgen; Thiel, Walter; Komornicki, Andrew

    1988-12-01

    Analytical first and second derivatives for effective core potentials are reported. The computational implementation of the derivative formulas makes use of new integral routines which take advantage of the shell concept. Test calculations for H 3SnBr and F 3AsS demonstrate the efficiency of the analytical determination of harmonic force fields using effective core potentials. The spectroscopic constants of the unknown molecule F 3AsS are predicted.

  14. Potentially improved glasses from space environment

    NASA Technical Reports Server (NTRS)

    Nichols, R.

    1977-01-01

    The benefits of processing glasses in a low-gravity space environment are examined. Containerless processing, the absence of gravity driven convection, and lack of sedimentation are seen as potential advantages. Potential applications include the formation of glass-ceramics with a high content of active elements for ferromagnetic devices, the production of ultrapure chalcogenide glasses for laser windows and IR fiber optics, and improved glass products for use in optical systems and laser fusion targets.

  15. Genomic Potential for Polysaccharide Deconstruction in Bacteria

    PubMed Central

    Martiny, Adam C.

    2014-01-01

    Glycoside hydrolases are important enzymes that support bacterial growth by enabling the degradation of polysaccharides (e.g., starch, cellulose, xylan, and chitin) in the environment. Presently, little is known about the overall phylogenetic distribution of the genomic potential to degrade these polysaccharides in bacteria. However, knowing the phylogenetic breadth of these traits may help us predict the overall polysaccharide processing in environmental microbial communities. In order to address this, we identified and analyzed the distribution of 392,166 enzyme genes derived from 53 glycoside hydrolase families in 8,133 sequenced bacterial genomes. Enzymes for oligosaccharides and starch/glycogen were observed in most taxonomic groups, whereas glycoside hydrolases for structural polymers (i.e., cellulose, xylan, and chitin) were observed in clusters of relatives at taxonomic levels ranging from species to genus as determined by consenTRAIT. The potential for starch and glycogen processing, as well as oligosaccharide processing, was observed in 85% of the strains, whereas 65% possessed enzymes to degrade some structural polysaccharides (i.e., cellulose, xylan, or chitin). Potential degraders targeting one, two, and three structural polysaccharides accounted for 22.6, 32.9, and 9.3% of genomes analyzed, respectively. Finally, potential degraders targeting multiple structural polysaccharides displayed increased potential for oligosaccharide deconstruction. This study provides a framework for linking the potential for polymer deconstruction with phylogeny in complex microbial assemblages. PMID:25527556

  16. Statistical systems with nonintegrable interaction potentials

    NASA Astrophysics Data System (ADS)

    Yukalov, V. I.

    2016-07-01

    Statistical systems composed of atoms interacting with each other trough nonintegrable interaction potentials are considered. Examples of these potentials are hard-core potentials and long-range potentials, for instance, the Lennard-Jones and dipolar potentials. The treatment of such potentials is known to confront several problems, e.g., the impossibility of using the standard mean-field approximations, such as Hartree and Hartree-Fock approximations, the impossibility of directly introducing coherent states, the difficulty in breaking the global gauge symmetry, which is required for describing Bose-Einstein condensed and superfluid systems, the absence of a correctly defined Fourier transform, which hampers the description of uniform matter as well as the use of local-density approximation for nonuniform systems. A novel iterative procedure for describing such systems is developed, starting from a correlated mean-field approximation, allowing for a systematic derivation of higher orders, and meeting no problems listed above. The procedure is applicable to arbitrary systems, whether equilibrium or nonequilibrium. The specification for equilibrium systems is presented. The method of extrapolating the expressions for observable quantities from weak coupling to strong coupling is described.

  17. Revisiting the argument from fetal potential

    PubMed Central

    Manninen, Bertha Alvarez

    2007-01-01

    One of the most famous, and most derided, arguments against the morality of abortion is the argument from potential, which maintains that the fetus' potential to become a person and enjoy the valuable life common to persons, entails that its destruction is prima facie morally impermissible. In this paper, I will revisit and offer a defense of the argument from potential. First, I will criticize the classical arguments proffered against the importance of fetal potential, specifically the arguments put forth by philosophers Peter Singer and David Boonin, by carefully unpacking the claims made in these arguments and illustrating why they are flawed. Secondly, I will maintain that fetal potential is morally relevant when it comes to the morality of abortion, but that it must be accorded a proper place in the argument. This proper place, however, cannot be found until we first answer a very important and complex question: we must first address the issue of personal identity, and when the fetus becomes the type of being who is relevantly identical to a future person. I will illustrate why the question of fetal potential can only be meaningfully addressed after we have first answered the question of personal identity and how it relates to the human fetus. PMID:17509146

  18. Gridded state maps of wind electric potential

    SciTech Connect

    Schwartz, M.N.; Elliott, D.L.; Gower, G.L.

    1992-10-01

    Estimates of wind electric potential and available windy land area in the contiguous United States, calculated in 1991, have been revised by incorporating actual data on the distribution of environmental exclusion areas where wind energy development would be prohibited or severely restricted. The new gridded data base with actual environmental exclusion areas, in combination with a 'moderate' land-use scenario, is the basis for developing the first gridded maps of available windy land and wind electric potential. Gridded maps for the 48 contiguous states show the estimated windy land area and electric potential for each grid cell (1/40 latitude by 1/30 longitude). These new maps show the distribution of the estimated wind electric potential and available windy land within an individual state, unlike previous national maps that only show estimates of the total wind electric potential for the state as a whole. While changes for some individual states are fairly large (in percentage), on a national basis, the estimated windy land area and wind electric potential are only about 1% to 2% higher than estimated in 1991.

  19. Fixman compensating potential for general branched molecules

    PubMed Central

    Jain, Abhinandan; Kandel, Saugat; Wagner, Jeffrey; Larsen, Adrien; Vaidehi, Nagarajan

    2013-01-01

    The technique of constraining high frequency modes of molecular motion is an effective way to increase simulation time scale and improve conformational sampling in molecular dynamics simulations. However, it has been shown that constraints on higher frequency modes such as bond lengths and bond angles stiffen the molecular model, thereby introducing systematic biases in the statistical behavior of the simulations. Fixman proposed a compensating potential to remove such biases in the thermodynamic and kinetic properties calculated from dynamics simulations. Previous implementations of the Fixman potential have been limited to only short serial chain systems. In this paper, we present a spatial operator algebra based algorithm to calculate the Fixman potential and its gradient within constrained dynamics simulations for branched topology molecules of any size. Our numerical studies on molecules of increasing complexity validate our algorithm by demonstrating recovery of the dihedral angle probability distribution function for systems that range in complexity from serial chains to protein molecules. We observe that the Fixman compensating potential recovers the free energy surface of a serial chain polymer, thus annulling the biases caused by constraining the bond lengths and bond angles. The inclusion of Fixman potential entails only a modest increase in the computational cost in these simulations. We believe that this work represents the first instance where the Fixman potential has been used for general branched systems, and establishes the viability for its use in constrained dynamics simulations of proteins and other macromolecules. PMID:24387353

  20. Statistical systems with nonintegrable interaction potentials.

    PubMed

    Yukalov, V I

    2016-07-01

    Statistical systems composed of atoms interacting with each other trough nonintegrable interaction potentials are considered. Examples of these potentials are hard-core potentials and long-range potentials, for instance, the Lennard-Jones and dipolar potentials. The treatment of such potentials is known to confront several problems, e.g., the impossibility of using the standard mean-field approximations, such as Hartree and Hartree-Fock approximations, the impossibility of directly introducing coherent states, the difficulty in breaking the global gauge symmetry, which is required for describing Bose-Einstein condensed and superfluid systems, the absence of a correctly defined Fourier transform, which hampers the description of uniform matter as well as the use of local-density approximation for nonuniform systems. A novel iterative procedure for describing such systems is developed, starting from a correlated mean-field approximation, allowing for a systematic derivation of higher orders, and meeting no problems listed above. The procedure is applicable to arbitrary systems, whether equilibrium or nonequilibrium. The specification for equilibrium systems is presented. The method of extrapolating the expressions for observable quantities from weak coupling to strong coupling is described. PMID:27575076

  1. Fixman compensating potential for general branched molecules

    SciTech Connect

    Jain, Abhinandan; Kandel, Saugat; Wagner, Jeffrey; Larsen, Adrien; Vaidehi, Nagarajan

    2013-12-28

    The technique of constraining high frequency modes of molecular motion is an effective way to increase simulation time scale and improve conformational sampling in molecular dynamics simulations. However, it has been shown that constraints on higher frequency modes such as bond lengths and bond angles stiffen the molecular model, thereby introducing systematic biases in the statistical behavior of the simulations. Fixman proposed a compensating potential to remove such biases in the thermodynamic and kinetic properties calculated from dynamics simulations. Previous implementations of the Fixman potential have been limited to only short serial chain systems. In this paper, we present a spatial operator algebra based algorithm to calculate the Fixman potential and its gradient within constrained dynamics simulations for branched topology molecules of any size. Our numerical studies on molecules of increasing complexity validate our algorithm by demonstrating recovery of the dihedral angle probability distribution function for systems that range in complexity from serial chains to protein molecules. We observe that the Fixman compensating potential recovers the free energy surface of a serial chain polymer, thus annulling the biases caused by constraining the bond lengths and bond angles. The inclusion of Fixman potential entails only a modest increase in the computational cost in these simulations. We believe that this work represents the first instance where the Fixman potential has been used for general branched systems, and establishes the viability for its use in constrained dynamics simulations of proteins and other macromolecules.

  2. Hydrogen Utilization Potential in Subsurface Sediments

    PubMed Central

    Adhikari, Rishi R.; Glombitza, Clemens; Nickel, Julia C.; Anderson, Chloe H.; Dunlea, Ann G.; Spivack, Arthur J.; Murray, Richard W.; D'Hondt, Steven; Kallmeyer, Jens

    2016-01-01

    Subsurface microbial communities undertake many terminal electron-accepting processes, often simultaneously. Using a tritium-based assay, we measured the potential hydrogen oxidation catalyzed by hydrogenase enzymes in several subsurface sedimentary environments (Lake Van, Barents Sea, Equatorial Pacific, and Gulf of Mexico) with different predominant electron-acceptors. Hydrogenases constitute a diverse family of enzymes expressed by microorganisms that utilize molecular hydrogen as a metabolic substrate, product, or intermediate. The assay reveals the potential for utilizing molecular hydrogen and allows qualitative detection of microbial activity irrespective of the predominant electron-accepting process. Because the method only requires samples frozen immediately after recovery, the assay can be used for identifying microbial activity in subsurface ecosystems without the need to preserve live material. We measured potential hydrogen oxidation rates in all samples from multiple depths at several sites that collectively span a wide range of environmental conditions and biogeochemical zones. Potential activity normalized to total cell abundance ranges over five orders of magnitude and varies, dependent upon the predominant terminal electron acceptor. Lowest per-cell potential rates characterize the zone of nitrate reduction and highest per-cell potential rates occur in the methanogenic zone. Possible reasons for this relationship to predominant electron acceptor include (i) increasing importance of fermentation in successively deeper biogeochemical zones and (ii) adaptation of H2ases to successively higher concentrations of H2 in successively deeper zones. PMID:26858697

  3. Hydrogen Utilization Potential in Subsurface Sediments.

    PubMed

    Adhikari, Rishi R; Glombitza, Clemens; Nickel, Julia C; Anderson, Chloe H; Dunlea, Ann G; Spivack, Arthur J; Murray, Richard W; D'Hondt, Steven; Kallmeyer, Jens

    2016-01-01

    Subsurface microbial communities undertake many terminal electron-accepting processes, often simultaneously. Using a tritium-based assay, we measured the potential hydrogen oxidation catalyzed by hydrogenase enzymes in several subsurface sedimentary environments (Lake Van, Barents Sea, Equatorial Pacific, and Gulf of Mexico) with different predominant electron-acceptors. Hydrogenases constitute a diverse family of enzymes expressed by microorganisms that utilize molecular hydrogen as a metabolic substrate, product, or intermediate. The assay reveals the potential for utilizing molecular hydrogen and allows qualitative detection of microbial activity irrespective of the predominant electron-accepting process. Because the method only requires samples frozen immediately after recovery, the assay can be used for identifying microbial activity in subsurface ecosystems without the need to preserve live material. We measured potential hydrogen oxidation rates in all samples from multiple depths at several sites that collectively span a wide range of environmental conditions and biogeochemical zones. Potential activity normalized to total cell abundance ranges over five orders of magnitude and varies, dependent upon the predominant terminal electron acceptor. Lowest per-cell potential rates characterize the zone of nitrate reduction and highest per-cell potential rates occur in the methanogenic zone. Possible reasons for this relationship to predominant electron acceptor include (i) increasing importance of fermentation in successively deeper biogeochemical zones and (ii) adaptation of H2ases to successively higher concentrations of H2 in successively deeper zones. PMID:26858697

  4. Renormalon Cancellation and Perturbative QCD Potential as a COULOMB+LINEAR Potential

    NASA Astrophysics Data System (ADS)

    Sumino, Y.

    2004-04-01

    Recently evidence has been found that the perturbative QCD potential agrees well with phenomenological potentials and lattice computations of the QCD potential. We discuss the present status of the perturbative QCD potential and theoretical backgrounds. We also report our recent analysis which shows analytically, on the basis of renormalon dominance picture, that the perturbative QCD potential quickly "converges" to a Coulomb-plus-linear form. The Coulomb-plus-linear potential can be computed systematically as we include more terms of the perturbative series; up to three-loop running (our current best knowledge), it shows a convergence towards lattice results. e.g. At one-loop running, the linear potential is σr with σ = ( {{{2π CF } {/ {{2π CF } {β 0 }}} ; . } {β 0 }}} ; )Λ {2 / {{MS}}} .

  5. Far-field potentials recorded from action potentials and from a tripole in a hemicylindrical volume.

    PubMed

    Jewett, D L; Deupree, D L

    1989-05-01

    There is growing evidence in support of the hypothesis that far-field potentials are recorded when action potentials encounter discontinuities in the surrounding volume. The present study found further support for this hypothesis using two methods of experimentation. The first method recorded potentials when the action potential from an isolated bullfrog sciatic nerve in a hemicylindrical volume (i) encountered a change in the shape of the surrounding volume, (ii) crossed a boundary between 2 volumes of differing resistivities, (iii) reached a bend in the nerve, or (iv) reached the functional end of the nerve. In the second method, potentials were recorded when an electrical tripole, constructed in a way to produce the electrical equivalent of an action potential, encountered the same discontinuities as well as when it was configured to simulate a curved nerve. These results are consistent with the hypothesis that dipole components of an action potential predominant in far-field recordings. PMID:2469568

  6. Determination of interionic potentials in molecules

    SciTech Connect

    Conradson, S.D.; Leon, J.M.; Bridges, F.

    1996-04-01

    The rationale underlying materials by design is that properties are determined by structure so that if the relationships between structure and properties are understood, an appropriate material can be designed and fabricated to meet any set of criteria. Since ion-ion potentials determine state transformations and reactivity, they are essential to the entire concept of materials and molecules by design. Virtually all of the important state-to-state processes undergone by molecules (excitation, relaxation, ionization, dissociation, and combination) and the selection among these different pathways are determined by the ion-ion potentials and the resulting degree of overlap between molecular vibrational states for different electronic and atomic configurations. Although the depths of these potentials can be obtained from thermodynamic data and the separations between the vibronic states from spectroscopic measurements, the use of these potentials in the ab initio calculation of state-transformation outcomes is limited by the absence of any direct method for determining their extent and shape. The authors have recently developed a generalization of x-ray absorption fine structure (XAFS) and a related set of experimental and analysis procedures that, in principle, will allow them to obtain such potentials from XAFS data. They have undertaken the analysis of temperature-dependent XAFS data of Cu, Ag, and Au to test the accuracy of existing analytical forms (the Morse potential for metals) in predicting the details of pair distributions and to determine the range of validity of a temperature-independent effective pair-potential approximation. This is the final report of a three-year Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL).

  7. Direct reconstruction of the quintessence potential

    NASA Astrophysics Data System (ADS)

    Sahlén, Martin; Liddle, Andrew R.; Parkinson, David

    2005-10-01

    We describe an algorithm which directly determines the quintessence potential from observational data, without using an equation of state parametrization. The strategy is to numerically determine observational quantities as a function of the expansion coefficients of the quintessence potential, which are then constrained using a likelihood approach. We further impose a model selection criterion, the Bayesian Information Criterion, to determine the appropriate level of the potential expansion. In addition to the potential parameters, the present day quintessence field velocity is kept as a free parameter. Our investigation contains unusual model types, including a scalar field moving on a flat potential, or in an uphill direction, and is general enough to permit oscillating quintessence field models. We apply our method to the “gold“ Type Ia supernovae sample of Riess et al. [A. G. Riess (Supernova Search Team Collaboration), Astrophys. J.ASJOAB0004-637X 607, 665 (2004)]10.1086/383612 confirming the pure cosmological constant model as the best description of current supernovae luminosity-redshift data. Our method is optimal for extracting quintessence parameters from future data.

  8. Screening Action Potentials: The Power of Light

    PubMed Central

    Kaestner, Lars; Lipp, Peter

    2011-01-01

    Action potentials reflect the concerted activity of all electrogenic constituents in the plasma membrane during the excitation of a cell. Therefore, the action potential is an integrated read out and a promising parameter to detect electrophysiological failures or modifications thereof in diagnosis as well as in drug screens. Cellular action potentials can be recorded by optical approaches. To fulfill the pre-requirements to scale up for, e.g., pharmacological screens the following preparatory work has to be provided: (i) model cells under investigation need to represent target cells in the best possible manner; (ii) optical sensors that can be either small molecule dyes or genetically encoded potential probes need to provide a reliable read out with minimal interaction with the naive behavior of the cells and (iii) devices need to be capable to stimulate the cells, read out the signals with the appropriate speed as well as provide the capacity for a sufficient throughput. Here we discuss several scenarios for all three categories in the field of cardiac physiology and pharmacology and provide a perspective to use the power of light in screening cardiac action potentials. PMID:21847381

  9. Search for tracker potentials in quintessence theory

    NASA Astrophysics Data System (ADS)

    Johri, Vinod B.

    2002-12-01

    We report a significant finding in quintessence theory that scalar fields with tracker potentials have a model-independent scaling behaviour in the expanding universe. So far, widely discussed exponential, power law or hyperbolic potentials can simply mimic the tracking behaviour over a limited range of redshift. A new version of the tracker field theory is proposed and it is shown that in the small redshift range where the variation of the tracking parameter ɛ may be taken to be negligible, the differential equation of generic potentials leads to hyperbolic sine and hyperbolic cosine potentials which may approximate a tracker field in the present-day universe. We have plotted the variation of the tracker potential and the equation of state of the tracker field as a function of the redshift z for the model-independent relation derived from tracker field theory; we have also plotted the variation of V(Φ) in terms of the scalar field Φ for the chosen hyperbolic cosine function and have compared it with the curves obtained by the reconstruction of V(Φ) from real observational data from the supernovae.

  10. Direct reconstruction of the quintessence potential

    SciTech Connect

    Sahlen, Martin; Liddle, Andrew R.; Parkinson, David

    2005-10-15

    We describe an algorithm which directly determines the quintessence potential from observational data, without using an equation of state parametrization. The strategy is to numerically determine observational quantities as a function of the expansion coefficients of the quintessence potential, which are then constrained using a likelihood approach. We further impose a model selection criterion, the Bayesian Information Criterion, to determine the appropriate level of the potential expansion. In addition to the potential parameters, the present day quintessence field velocity is kept as a free parameter. Our investigation contains unusual model types, including a scalar field moving on a flat potential, or in an uphill direction, and is general enough to permit oscillating quintessence field models. We apply our method to the 'gold' Type Ia supernovae sample of Riess et al. [A. G. Riess et al. (Supernova Search Team Collaboration), Astrophys. J. 607, 665 (2004)] confirming the pure cosmological constant model as the best description of current supernovae luminosity-redshift data. Our method is optimal for extracting quintessence parameters from future data.

  11. Relationships between Depression and High Intellectual Potential

    PubMed Central

    Weismann-Arcache, Catherine; Tordjman, Sylvie

    2012-01-01

    This paper proposes to analyse the relationships between depression and high intellectual potential through a multidisciplinary and original approach. Based on their respective experience in psychology and child psychiatry, the authors will focus their analysis on creative potential. First, relationships between creativity (literary, artistic, or scientific creativity) and melancholy (“melancholy” comes from the Greek words for “black” (“melas”) and “bile” (“khole”)) will be examined from antiquity to modern times. Aristotle introduced a quantitative factor, asserting that levels of melancholy and black bile are positively correlated; however, under a given threshold of black bile, it can give rise to an exceptional being. Second, the case study of Blaise Pascal (scientific and philosophical creativity associated with major depressive episodes from childhood) will be presented and discussed. This case study sheds light on the paradoxical role of depression in the overinvestment in intellectual and creative spheres as well as on the impact of traumatic events on high intellectual potential. Third, observations will be reported based on a study conducted on 100 children with high intellectual potential (6–12 years old). Finally, based on these different levels of analysis, it appears that heterogeneity of mental functioning in children with high intellectual potential is at the center of the creative process and it has related psychological vulnerability. PMID:22645671

  12. Temperature dependence of soil water potential

    SciTech Connect

    Mohamed, A.M.O.; Yong, R.N. ); Cheung, S.C.H. )

    1992-12-01

    To understand the process of coupled heat and water transport, the relationship between temperature and soil water potential must be known. Two clays, Avonlea bentonite and Lake Agassiz clay, are being considered as the clay-based sealing materials for the Canadian nuclear fuel waste disposal vault. Avonlea bentonite is distinguished from Lake Agassiz clay by its high sealing potential in water. A series of experiments was performed in which the two clays were mixed with equal amounts of sand and were compacted to a dry density of 1.67 Mg/m[sup 3] under various moisture contents and temperatures. A psychrometer was placed within the compacted clay-sand to measure the soil water potential based on the electromotive force measured by the psychrometer. The results indicate that the soil water potential at a particular temperature is higher for both clay-sand mixtures than predicted by the change in the surface tension of water; this effect is much more prominent in the Avonlea bentonite and at low moisture contents. The paper presents empirical equations relating the soil water potential with the moisture content and temperature of the two clay-sand mixtures. 24 refs., 8 figs., 2 tabs.

  13. Characterization of the Variation Potential in Sunflower.

    PubMed Central

    Stankovic, B.; Zawadzki, T.; Davies, E.

    1997-01-01

    A major candidate for intercellular signaling in higher plants is the stimulus-induced systemic change in membrane potential known as variation potential (VP). We investigated the mechanism of occurrence and long-distance propagation of VP in sunflower (Helianthus annuus L.) plants. Here we present evidence of the relationship among injury-induced changes in xylem tension, turgor pressure, and electrical potential. Although locally applied wounding did trigger a change in membrane potential, it evoked even faster changes in tissue deformation, apparently resulting from pressure surges rapidly transmitted through the xylem and experienced throughout the plant. Externally applied pressure mimicked flame wounding by triggering an electrical response resembling VP. Our findings suggest that VP in sunflower is not a propagating change in electrical potential and not the consequence of chemicals transmitted via the xylem, affecting ligand-modulated ion channels. Instead, VP appears to result from the surge in pressure in the xylem causing a change in activity of mechanosensitive, stretch-responsive ion channels or pumps in adjacent, living cells. The ensuing ion flux evokes local plasma membrane depolarization, which is monitored extracellularly as VP. PMID:12223859

  14. Interpolation effects in tabulated interatomic potentials

    NASA Astrophysics Data System (ADS)

    Wen, M.; Whalen, S. M.; Elliott, R. S.; Tadmor, E. B.

    2015-10-01

    Empirical interatomic potentials are widely used in atomistic simulations due to their ability to compute the total energy and interatomic forces quickly relative to more accurate quantum calculations. The functional forms in these potentials are sometimes stored in a tabulated format, as a collection of data points (argument-value pairs), and a suitable interpolation (often spline-based) is used to obtain the function value at an arbitrary point. We explore the effect of these interpolations on the potential predictions by calculating the quasi-harmonic thermal expansion and finite-temperature elastic constant of a one-dimensional chain compared with molecular dynamics simulations. Our results show that some predictions are affected by the choice of interpolation regardless of the number of tabulated data points. Our results clearly indicate that the interpolation must be considered part of the potential definition, especially for lattice dynamics properties that depend on higher-order derivatives of the potential. This is facilitated by the Knowledgebase of Interatomic Models (KIM) project, in which both the tabulated data (‘parameterized model’) and the code that interpolates them to compute energy and forces (‘model driver’) are stored and given unique citeable identifiers. We have developed cubic and quintic spline model drivers for pair functional type models (EAM, FS, EMT) and uploaded them to the OpenKIM repository (https://openkim.org).

  15. The Lambert-W step-potential - an exactly solvable confluent hypergeometric potential

    NASA Astrophysics Data System (ADS)

    Ishkhanyan, A. M.

    2016-02-01

    We present an asymmetric step-barrier potential for which the one-dimensional stationary Schrödinger equation is exactly solved in terms of the confluent hypergeometric functions. The potential is given in terms of the Lambert W-function, which is an implicitly elementary function also known as the product logarithm. We present the general solution of the problem and consider the quantum reflection at transmission of a particle above this potential barrier. Compared with the abrupt-step and hyperbolic tangent potentials, which are reproduced by the Lambert potential in certain parameter and/or variable variation regions, the reflection coefficient is smaller because of the lesser steepness of the potential on the particle incidence side. Presenting the derivation of the Lambert potential we show that this is a four-parametric sub-potential of a more general five-parametric one also solvable in terms of the confluent hypergeometric functions. The latter potential, however, is a conditionally integrable one. Finally, we show that there exists one more potential the solution for which is written in terms of the derivative of a bi-confluent Heun function.

  16. Active control of electric potential of spacecraft

    NASA Technical Reports Server (NTRS)

    Goldstein, R.

    1977-01-01

    Techniques are discussed for controlling the potential of a spacecraft by means of devices which release appropriate charged particles from the spacecraft to the environment. Attention is given to electron emitters, ion emitters, a basic electron emitter arrangement, techniques for sensing electric field or potential, and flight experiments on active potential control. It is recommended to avoid differential charging on spacecraft surfaces because it can severely affect the efficacy of emitters. Discharging the frame of a spacecraft with dielectric surfaces involves the risk of stressing the dielectric material excessively. The spacecraft should, therefore, be provided with grounded conductive surfaces. It is pointed out that particles released by control systems can return to the spacecraft.

  17. Local density dependent potential for compressible mesoparticles

    NASA Astrophysics Data System (ADS)

    Faure, Gérôme; Maillet, Jean-Bernard; Stoltz, Gabriel

    2014-03-01

    This work proposes a coarse grained description of molecular systems based on mesoparticles representing several molecules, where interactions between mesoparticles are modelled by an interparticle potential of molecular type. Since strong non-equilibrium situations over a wide range of pressure and density are targeted, the internal compressibility of the mesoparticles has to be considered. This is done by introducing a dependence of the potential on the local environment of the mesoparticles. To define local densities, we resort to a three-dimensional Voronoi tessellation instead of standard local, spherical averages. As an example, a local density dependent potential is fitted to reproduce the Hugoniot curve of a model of nitromethane over a large range of pressures and densities.

  18. Extracting molecular potentials from incomplete spectroscopic information

    NASA Astrophysics Data System (ADS)

    Li, Xuan; Dutta, Sourav

    2015-12-01

    We extend our recently developed inversion method to extract excited-state potentials from fluorescence line positions and line strengths. We consider a previous limitation of the method arising due to insufficient input data in cases where the relatively weaker emission data are not experimentally available. We develop a solution to this problem by 'regenerating' these weak transition lines via applying a model potential, e.g. a Morse potential. The result of this procedure, illustrated for the Q-branch emission from the lowest three vibrational levels of the B(1Π) state of LiRb, is shown to have an error of 0.29 cm-1 in the classically allowed region and a global error of 5.67 cm-1 for V ≤ E(ν‧ = 10). The robustness of this procedure is also demonstrated by considering the statistical error in the measured line intensities.

  19. Potential runoff-contributing areas in Kansas

    USGS Publications Warehouse

    Juracek, Kyle E.

    2000-01-01

    This digital spatial data set provides information on the spatial distribution of potential runoff-contributing areas in the State of Kansas. Potential runoff-contributing areas were estimated collectively for the processes of infiltration-excess overland flow and saturation-excess overland flow. For infiltration-excess overland flow, various rainfall-intensity and soil-permeability values were used. For saturation-excess overland flow, antecedent soil-moisture conditions and a topographic wetness index were used. The digital data sets used in the analysis included 1:24,000-scale soils data and a 100-meter-resolution digital elevation model. The data set of potential runoff-contributing areas is in grid (raster) format with a grid-cell size of 10,000 square meters.

  20. Dietary chalcones with chemopreventive and chemotherapeutic potential.

    PubMed

    Orlikova, Barbora; Tasdemir, Deniz; Golais, Frantisek; Dicato, Mario; Diederich, Marc

    2011-05-01

    Chalcones are absorbed in the daily diet and appear to be promising cancer chemopreventive agents. Chalcones represent an important group of the polyphenolic family, which includes a large number of naturally occurring molecules. This family possesses an interesting spectrum of biological activities, including antioxidative, antibacterial, anti-inflammatory, anticancer, cytotoxic, and immunosuppressive potential. Compounds of this family have been shown to interfere with each step of carcinogenesis, including initiation, promotion and progression. Moreover, numerous compounds from the family of dietary chalcones appear to show activity against cancer cells, suggesting that these molecules or their derivatives may be considered as potential anticancer drugs. This review will focus primarily on prominent members of the chalcone family with an 1,3-diphenyl-2-propenon core structure. Specifically, the inhibitory effects of these compounds on the different steps of carcinogenesis that reveal interesting chemopreventive and chemotherapeutic potential will be discussed. PMID:21484163

  1. Current wound healing procedures and potential care

    PubMed Central

    Dreifke, Michael B.; Jayasuriya, Amil A.; Jayasuriya, Ambalangodage C.

    2015-01-01

    In this review, we describe current and future potential wound healing treatments for acute and chronic wounds. The current wound healing approaches are based on autografts, allografts, and cultured epithelial autografts, and wound dressings based on biocompatible and biodegradable polymers. The Food and Drug Administration approved wound healing dressings based on several polymers including collagen, silicon, chitosan, and hyaluronic acid. The new potential therapeutic intervention for wound healing includes sustained delivery of growth factors, and siRNA delivery, targeting micro RNA, and stem cell therapy. In addition, environment sensors can also potentially utilize to monitor and manage micro environment at wound site. Sensors use optical, odor, pH, and hydration sensors to detect such characteristics as uric acid level, pH, protease level, and infection – all in the hopes of early detection of complications. PMID:25579968

  2. Nanoparticles and cars - analysis of potential sources

    PubMed Central

    2012-01-01

    Urban health is potentially affected by particle emissions. The potential toxicity of nanoparticles is heavily debated and there is an enormous global increase in research activity in this field. In this respect, it is commonly accepted that nanoparticles may also be generated in processes occurring while driving vehicles. So far, a variety of studies addressed traffic-related particulate matter emissions, but only few studies focused on potential nanoparticles. Therefore, the present study analyzed the literature with regard to nanoparticles and cars. It can be stated that, to date, only a limited amount of research has been conducted in this area and more studies are needed to 1) address kind and sources of nanoparticles within automobiles and to 2) analyse whether there are health effects caused by these nanoparticles. PMID:22726351

  3. Potential Condensed Fuel for the Milky Way

    NASA Astrophysics Data System (ADS)

    Putman, M. E.

    2006-07-01

    Potential condensed clouds of gas in the Galactic halo are examined in the context of the recent models of cooling, fragmenting clouds building up the baryonic mass of the Galaxy. Five hundred and eighty-two high-velocity clouds are defined as the potential condensed clouds, and the sample's spatial and velocity distributions are presented. With the majority of the hydrogen in the clouds ionized (~85%), the clouds at a distribution of distances within 150 kpc, and their individual total masses below 107 Msolar, the total mass in potentially condensed clouds is (1.1-1.4)×109 Msolar. If the tighter distance constraint of <60 kpc is adopted, this mass range drops to (4.5-6.1)×108 Msolar. The implications for the condensing cloud models, as well as feedback and additional accretion methods, are discussed.

  4. Cystic fibrosis transmembrane regulator correctors and potentiators.

    PubMed

    Rowe, Steven M; Verkman, Alan S

    2013-07-01

    Cystic fibrosis (CF) is caused by loss-of-function mutations in the CF transmembrane conductance regulator (CFTR) protein, a cAMP-regulated anion channel expressed primarily at the apical plasma membrane of secretory epithelia. Nearly 2000 mutations in the CFTR gene have been identified that cause disease by impairing its translation, cellular processing, and/or chloride channel gating. The fundamental premise of CFTR corrector and potentiator therapy for CF is that addressing the underlying defects in the cellular processing and chloride channel function of CF-causing mutant CFTR alleles will result in clinical benefit by addressing the basic defect underlying CF. Correctors are principally targeted at F508del cellular misprocessing, whereas potentiators are intended to restore cAMP-dependent chloride channel activity to mutant CFTRs at the cell surface. This article reviews the discovery of CFTR potentiators and correctors, what is known regarding their mechanistic basis, and encouraging results achieved in clinical testing. PMID:23818513

  5. Cystic Fibrosis Transmembrane Regulator Correctors and Potentiators

    PubMed Central

    Rowe, Steven M.; Verkman, Alan S.

    2013-01-01

    Cystic fibrosis (CF) is caused by loss-of-function mutations in the CF transmembrane conductance regulator (CFTR) protein, a cAMP-regulated anion channel expressed primarily at the apical plasma membrane of secretory epithelia. Nearly 2000 mutations in the CFTR gene have been identified that cause disease by impairing its translation, cellular processing, and/or chloride channel gating. The fundamental premise of CFTR corrector and potentiator therapy for CF is that addressing the underlying defects in the cellular processing and chloride channel function of CF-causing mutant CFTR alleles will result in clinical benefit by addressing the basic defect underlying CF. Correctors are principally targeted at F508del cellular misprocessing, whereas potentiators are intended to restore cAMP-dependent chloride channel activity to mutant CFTRs at the cell surface. This article reviews the discovery of CFTR potentiators and correctors, what is known regarding their mechanistic basis, and encouraging results achieved in clinical testing. PMID:23818513

  6. Electrical potential difference during laser welding

    NASA Astrophysics Data System (ADS)

    Zohm, H.; Ambrosy, G.; Lackner, K.

    2015-01-01

    We present a new model for the generation of thermoelectric currents during laser welding, taking into account sheath effects at both contact points as well as the potential drop within the quasi-neutral plasma generated by the laser. We show that the model is in good agreement with experimentally measured electric potential difference between the hot and the cold parts of the welded workpiece. In particular, all three elements of the model are needed to correctly reproduce the sign of the measured voltage difference. The mechanism proposed relies on the temperature dependence of the electron flux from the plasma to the workpiece and hence does not need thermoemission from the workpiece surface to explain the experimentally observed sign and magnitude of the potential drop.

  7. On Effective Potential in Tortoise Coordinate

    NASA Astrophysics Data System (ADS)

    Ganjali, M. A.

    2012-08-01

    In this paper, we study the field dynamics in Tortoise coordinate where the equation of motion of a scalar can be written as Schrodinger-like form. We obtain a general form for effective potential by finding the Schrodinger equation for scalar and spinor fields and study its global behavior in some black hole backgrounds in three dimension such as BTZ black holes, new type black holes and black holes with no horizon. Especially, we study the asymptotic behavior of potential at infinity, horizons and origin and find that its asymptotic in BTZ and new type solution is completely different from that of vanishing horizon solution. In fact, potential for vanishing horizon goes to a fixed quantity at infinity, while in BTZ and new type black hole we have an infinite barrier.

  8. Exploring the potential of public proteomics data

    PubMed Central

    Vaudel, Marc; Verheggen, Kenneth; Csordas, Attila; Ræder, Helge; Berven, Frode S.; Martens, Lennart; Vizcaíno, Juan A.

    2015-01-01

    In a global effort for scientific transparency, it has become feasible and good practice to share experimental data supporting novel findings. Consequently, the amount of publicly available MS‐based proteomics data has grown substantially in recent years. With some notable exceptions, this extensive material has however largely been left untouched. The time has now come for the proteomics community to utilize this potential gold mine for new discoveries, and uncover its untapped potential. In this review, we provide a brief history of the sharing of proteomics data, showing ways in which publicly available proteomics data are already being (re‐)used, and outline potential future opportunities based on four different usage types: use, reuse, reprocess, and repurpose. We thus aim to assist the proteomics community in stepping up to the challenge, and to make the most of the rapidly increasing amount of public proteomics data. PMID:26449181

  9. Remote sensing of potential aircraft icing areas

    NASA Astrophysics Data System (ADS)

    Zuev, Vladimir V.; Nakhtigalova, Daria P.; Shelekhov, Alexander P.; Shelekhova, Evgeniya A.; Baranov, Nikolay A.; Kizhner, Lubov I.

    2015-11-01

    Remote sensing technique of detection of potential aircraft icing areas based on temperature profile measurements, using meteorological temperature profiler, and the data of the Airfield Measuring and Information System (AMIS-RF), was proposed, theoretically described and experimentally validated during the field project in 2012 - 2013 in the Tomsk Bogashevo Airport. Spatial areas of potential aircraft icing were determined using the RAP algorithm and Godske formula. The equations for the reconstruction of profiles of relative humidity and dew point using data from AMIS-RF are given. Actual data on the aircraft icing for the Tomsk Bogashevo Airport on 11 October 2012 and 17 March 2013 are presented in this paper. The RAP algorithm and Godske formula show similar results for the location of spatial areas of potential icing. Though, the results obtained using the RAP algorithm are closer to the actual data on the icing known from aircraft crew reports.

  10. A new interaction potential for swarming models

    NASA Astrophysics Data System (ADS)

    Carrillo, J. A.; Martin, S.; Panferov, V.

    2013-10-01

    We consider a self-propelled particle system which has been used to describe certain types of collective motion of animals, such as fish schools and bird flocks. Interactions between particles are specified by means of a pairwise potential, repulsive at short ranges and attractive at longer ranges. The exponentially decaying Morse potential is a typical choice, and is known to reproduce certain types of collective motion observed in nature, particularly aligned flocks and rotating mills. We introduce a class of interaction potentials, that we call Quasi-Morse, for which flock and rotating mills states are also observed numerically, however in that case the corresponding macroscopic equations allow for explicit solutions in terms of special functions, with coefficients that can be obtained numerically without solving the particle evolution. We compare the obtained solutions with long-time dynamics of the particle systems and find a close agreement for several types of flock and mill solutions.

  11. Gastroesophageal reflux: a potential asthma trigger.

    PubMed

    Harding, Susan M

    2005-02-01

    Gastroesophageal reflux (GER) is a potential trigger of asthma. Approximately 77% of asthmatics report heartburn. GER is a risk factor for asthma-related hospitalization and oral steroid burst use. Asthmatics may be predisposed to GER development because of a high prevalence of hiatal hernia and autonomic dysregulation and an increased pressure gradient between the abdominal cavity and the thorax, over-riding the lower esophageal sphincter pressure barrier. Asthma medications may potentiate GER. Potential mechanisms of esophageal acid-induced bronchoconstriction include a vagally mediated reflex, local axonal reflexes, heightened bronchial reactivity, and microaspiration, all resulting in neurogenic inflammation. Anti-reflux therapy improves asthma symptoms in approximately 70% of asthmatics with GER. A 3-month empiric trial of twice-daily proton pump inhibitor given 30 to 60 minutes before breakfast and dinner can identify asthmatics who have GER as a trigger of their asthma. PMID:15579368

  12. Numerical matrix method for quantum periodic potentials

    NASA Astrophysics Data System (ADS)

    Le Vot, Felipe; Meléndez, Juan J.; Yuste, Santos B.

    2016-06-01

    A numerical matrix methodology is applied to quantum problems with periodic potentials. The procedure consists essentially in replacing the true potential by an alternative one, restricted by an infinite square well, and in expressing the wave functions as finite superpositions of eigenfunctions of the infinite well. A matrix eigenvalue equation then yields the energy levels of the periodic potential within an acceptable accuracy. The methodology has been successfully used to deal with problems based on the well-known Kronig-Penney (KP) model. Besides the original model, these problems are a dimerized KP solid, a KP solid containing a surface, and a KP solid under an external field. A short list of additional problems that can be solved with this procedure is presented.

  13. Effects of potential functions on stochastic resonance

    NASA Astrophysics Data System (ADS)

    Li, Jian-Long; Zeng, Ling-Zao

    2011-01-01

    In this paper, the effects of a bistable potential function U(x) = —ax2/2 + b|x|2γ/(2γ) on stochastic resonance (SR) is discussed. We investigate the effects of index γ on the performance of the SR system with fixed parameters a and b, and with fixed potential barriers, respectively. To measure the performance of the SR system in the presence of an aperiodic input, the bit error rate is employed, as is commonly used in binary communications. The numerical simulations strongly support the theoretical results. The goal of this investigation is to explore the effects of the shape of potential functions on SR and give a guidance of nonlinear systems in the application of information processing.

  14. Movement-related potentials in Parkinson's disease.

    PubMed

    Georgiev, Dejan; Lange, Florian; Seer, Caroline; Kopp, Bruno; Jahanshahi, Marjan

    2016-06-01

    To date, many different approaches have been used to study the impairment of motor function in Parkinson's disease (PD). Event-related potentials (ERPs) are averaged amplitude fluctuations of the ongoing EEG activity that are time locked to specific sensory, motor or cognitive events, and as such can be used to study different brain processes with an excellent temporal resolution. Movement-related potentials (MRPs) are ERPs associated with processes of voluntary movement preparation and execution in different paradigms. In this review we concentrate on MRPs in PD. We review studies recording the Bereitschaftspotential, the Contingent Negative Variation, and the lateralized readiness potential in PD to highlight the contributions they have made to further understanding motor deficits in PD. Possible directions for future research are also discussed. PMID:27178872

  15. Electric sail missions to potentially hazardous asteroids

    NASA Astrophysics Data System (ADS)

    Quarta, Alessandro A.; Mengali, Giovanni

    2010-05-01

    Missions towards potentially hazardous asteroids require considerable propellant-mass consumption and complex flybys maneuvers with conventional propulsion systems. A very promising option is offered by an electric sail, an innovative propulsion concept, that uses the solar-wind dynamic pressure for generating a continuous and nearly radial thrust without the need for reaction mass. The aim of this paper is to investigate the performance of such a propulsion system for performing rendezvous missions towards all the currently known potentially hazardous asteroids, a total of 1025 missions. The problem is studied in an optimal framework by minimizing the total flight time. Assuming a canonical value of sail characteristic acceleration, we show that about 67% of the potentially hazardous asteroids may be reached within one year of mission time, with 137 rendezvous in the first six months. A detailed study towards asteroid 99942 Apophis is reported, and a comparison with the corresponding performance achievable with a flat solar sail is discussed.

  16. Potential flow inside an evaporating cylindrical line.

    PubMed

    Petsi, A J; Burganos, V N

    2005-10-01

    An analytical solution to the problem of potential flow inside an evaporating line is obtained. The line is shaped as a half-cylinder lying on a substrate, and evaporates with either pinned or depinned contact lines. The solution is provided through the technique of separation of variables in the velocity potential and stream function formulations. Based on the flow field calculations, it is estimated that the coffee-stain phenomenon should be expected even for uniform evaporation flux throughout the cylindrical surface, provided that the contact lines remain anchored. A simple expression for the velocity potential is also suggested, which reproduces the local velocity vector with excellent accuracy. The vertically averaged velocity is calculated also for other contact line values, revealing for any value an outward liquid flow for pinned lines as opposed to inward flow for depinned lines. PMID:16383581

  17. Antimatter Production at a Potential Boundary

    NASA Technical Reports Server (NTRS)

    LaPointe, Michael R.; Reddy, Dhanireddy (Technical Monitor)

    2001-01-01

    Current antiproton production techniques rely on high-energy collisions between beam particles and target nuclei to produce particle and antiparticle pairs, but inherently low production and capture efficiencies render these techniques impractical for the cost-effective production of antimatter for space propulsion and other commercial applications. Based on Dirac's theory of the vacuum field, a new antimatter production concept is proposed in which particle-antiparticle pairs are created at the boundary of a steep potential step formed by the suppression of the local vacuum fields. Current antimatter production techniques are reviewed, followed by a description of Dirac's relativistic quantum theory of the vacuum state and corresponding solutions for particle tunneling and reflection from a potential barrier. The use of the Casimir effect to suppress local vacuum fields is presented as a possible technique for generating the sharp potential gradients required for particle-antiparticle pair creation.

  18. Potential effects of gallium on cladding materials

    SciTech Connect

    Wilson, D.F.; Beahm, E.C.; Besmann, T.M.; DeVan, J.H.; DiStefano, J.R.; Gat, U.; Greene, S.R.; Rittenhouse, P.L.; Worley, B.A.

    1997-10-01

    This paper identifies and examines issues concerning the incorporation of gallium in weapons derived plutonium in light water reactor (LWR) MOX fuels. Particular attention is given to the more likely effects of the gallium on the behavior of the cladding material. The chemistry of weapons grade (WG) MOX, including possible consequences of gallium within plutonium agglomerates, was assessed. Based on the calculated oxidation potentials of MOX fuel, the effect that gallium may have on reactions involving fission products and possible impact on cladding performance were postulated. Gallium transport mechanisms are discussed. With an understanding of oxidation potentials and assumptions of mechanisms for gallium transport, possible effects of gallium on corrosion of cladding were evaluated. Potential and unresolved issues and suggested research and development (R and D) required to provide missing information are presented.

  19. Constant-force approach to discontinuous potentials.

    PubMed

    Orea, Pedro; Odriozola, Gerardo

    2013-06-01

    Aiming to approach the thermodynamical properties of hard-core systems by standard molecular dynamics simulation, we propose setting a repulsive constant-force for overlapping particles. That is, the discontinuity of the pair potential is replaced by a linear function with a large negative slope. Hence, the core-core repulsion, usually modeled with a power function of distance, yields a large force as soon as the cores slightly overlap. This leads to a quasi-hardcore behavior. The idea is tested for a triangle potential of short range. The results obtained by replica exchange molecular dynamics for several repulsive forces are contrasted with the ones obtained for the discontinuous potential and by means of replica exchange Monte Carlo. We found remarkable agreements for the vapor-liquid coexistence densities as well as for the surface tension. PMID:23758356

  20. Microscopic optical buffering in a harmonic potential

    NASA Astrophysics Data System (ADS)

    Sumetsky, M.

    2015-12-01

    In the early days of quantum mechanics, Schrödinger noticed that oscillations of a wave packet in a one-dimensional harmonic potential well are periodic and, in contrast to those in anharmonic potential wells, do not experience distortion over time. This original idea did not find applications up to now since an exact one-dimensional harmonic resonator does not exist in nature and has not been created artificially. However, an optical pulse propagating in a bottle microresonator (a dielectric cylinder with a nanoscale-high bump of the effective radius) can exactly imitate a quantum wave packet in the harmonic potential. Here, we propose a tuneable microresonator that can trap an optical pulse completely, hold it as long as the material losses permit, and release it without distortion. This result suggests the solution of the long standing problem of creating a microscopic optical buffer, the key element of the future optical signal processing devices.

  1. Bond order potential module for LAMMPS

    Energy Science and Technology Software Center (ESTSC)

    2012-09-11

    pair_bop is a module for performing energy calculations using the Bond Order Potential (BOP) for use in the parallel molecular dynamics code LAMMPS. The bop pair style computes BOP based upon quantum mechanical incorporating both sigma and pi bondings. By analytically deriving the BOP pair bop from quantum mechanical theory its transferability to different phases can approach that of quantum mechanical methods. This potential is extremely effective at modeling 111-V and II-VI compounds such asmore » GaAs and CdTe. This potential is similar to the original BOP developed by Pettifor and later updated by Murdock et al. and Ward et al.« less

  2. Earning potential in multilevel marketing enterprises

    NASA Astrophysics Data System (ADS)

    Legara, Erika Fille; Monterola, Christopher; Juanico, Dranreb Earl; Litong-Palima, Marisciel; Saloma, Caesar

    2008-08-01

    Government regulators and other concerned citizens warily view multilevel marketing enterprises (MLM) because of their close operational resemblance to exploitative pyramid schemes. We analyze two types of MLM network architectures - the unilevel and binary, in terms of growth behavior and earning potential among members. We show that network growth decelerates after reaching a size threshold, contrary to claims of unrestricted growth by MLM recruiters. We have also found that the earning potential in binary MLM’s obey the Pareto “80-20” rule, implying an earning opportunity that is strongly biased against the most recent members. On the other hand, unilevel MLM’s do not exhibit the Pareto earning distribution and earning potential is independent of member position in the network. Our analytical results agree well with field data taken from real-world MLM’s in the Philippines. Our analysis is generally valid and can be applied to other MLM architectures.

  3. Measuring defibrillator surface potentials for simulation verification.

    PubMed

    Tate, Jess; Stinstra, Jeroen; Pilcher, Thomas; Poursaid, Ahrash; Saarel, Elizabeth; MacLeod, Rob

    2011-01-01

    Though implantable cardioverter defibrillators (ICDs) are increasing in use in both adults and children, little progress has been devoted to optimizing device and electrode placement. To facilitate effective ICD placement, especially in pediatric cases, we have developed a predictive model that evaluates the efficacy of a delivered shock. We have also developed an experimental validation approach based on measurements from clinical cases. The approach involves obtaining body surface potential maps of ICD discharges during implantation surgery using a limited lead selection and body surface estimation algorithm. Comparison of the simulated and measured potentials yielded very similar patterns and a typical correlation greater than 0.93, suggesting that the predictive simulation generates realistic potential values. This validation approach provides confidence in application of the simulation pipeline and offers areas to focus future improvements. PMID:22254294

  4. Effective potential in density matrix functional theory.

    PubMed

    Nagy, A; Amovilli, C

    2004-10-01

    In the previous paper it was shown that in the ground state the diagonal of the spin independent second-order density matrix n can be determined by solving a single auxiliary equation of a two-particle problem. Thus the problem of an arbitrary system with even electrons can be reduced to a two-particle problem. The effective potential of the two-particle equation contains a term v(p) of completely kinetic origin. Virial theorem and hierarchy of equations are derived for v(p) and simple approximations are proposed. A relationship between the effective potential u(p) of the shape function equation and the potential v(p) is established. PMID:15473719

  5. The potential dependence of porous silicon electroluminescence

    SciTech Connect

    Riley, D.J.; Peter, L.M.; Wielgosz, R.I.

    1996-10-01

    The observation of visible luminescence from porous silicon has resulted in strong interest in this material. It has been demonstrated that the electrochemical reduction of persulfate ions at a porous silicon electrode/electrolyte interface may lead to intense luminescence (electroluminescence). Further, it has been found that the intensity and wavelength of the electroluminescence is potential dependent, this phenomenon is termed {open_quotes}potential tuning{close_quotes}. This paper is concerned with the elucidation of the mechanism of electroluminescence potential tuning. It will be shown that the process is related to the particle size distribution and the dynamics of electron transfer between the bulk silicon substrate, the surface silicon nanocrystals and the electrolyte. Further, the results of combined in-situ FTIR and electroluminescence studies will be reported. The influence of surface chemistry on the electroluminescence will be discussed with reference to the proposed {open_quotes}tuning{close_quotes} mechanism.

  6. Microscopic optical buffering in a harmonic potential

    PubMed Central

    Sumetsky, M.

    2015-01-01

    In the early days of quantum mechanics, Schrödinger noticed that oscillations of a wave packet in a one-dimensional harmonic potential well are periodic and, in contrast to those in anharmonic potential wells, do not experience distortion over time. This original idea did not find applications up to now since an exact one-dimensional harmonic resonator does not exist in nature and has not been created artificially. However, an optical pulse propagating in a bottle microresonator (a dielectric cylinder with a nanoscale-high bump of the effective radius) can exactly imitate a quantum wave packet in the harmonic potential. Here, we propose a tuneable microresonator that can trap an optical pulse completely, hold it as long as the material losses permit, and release it without distortion. This result suggests the solution of the long standing problem of creating a microscopic optical buffer, the key element of the future optical signal processing devices. PMID:26689546

  7. Origin of growth-induced water potential

    SciTech Connect

    Nonami, H.; Boyer, J.S.

    1987-03-01

    The authors developed a new method to measure the solute concentration in the apoplast of stem tissue involving pressurizing the roots of intact seedlings (Glycine max (L.) Merr. or Pisum sativum L.), collecting a small amount of exudate from the surface of the stem under saturating humidities, and determining the osmotic potential of the solution with a micro-osmometer capable of measuring small volumes (0.5 microliter). In the elongating region, the apoplast concentrations were very low (equivalent to osmotic potentials of -0.03 to -0.04 megapascal) and negligible compared to the water potential of the apoplast (-0.15 to -0.30 megapascal) measured directly by isopiestic psychrometry in intact plants. Most of the apoplast water potential consisted of a negative pressure that could be measured with a pressure chamber (-0.15 to -0.28 megapascal). Tests showed that earlier methods involving infiltration of intercellular spaces or pressurizing cut segments caused solute to be released to the apoplast and resulted in spuriously high concentrations. These results indicate that, although a small amount of solute is present in the apoplast, the major component is a tension that is part of a growth-induced gradient in water potential in the enlarging tissue. The gradient originates from the extension of the cell walls, which prevents turgor from reaching its maximum and creates a growth-induced water potential that causes water to move from the xylem at a rate that satisfies the rate of enlargement. The magnitude of the gradient implies that growing tissue contains a large resistance to water movement.

  8. Next generation interatomic potentials for condensed systems

    NASA Astrophysics Data System (ADS)

    Handley, Christopher Michael; Behler, Jörg

    2014-07-01

    The computer simulation of condensed systems is a challenging task. While electronic structure methods like density-functional theory (DFT) usually provide a good compromise between accuracy and efficiency, they are computationally very demanding and thus applicable only to systems containing up to a few hundred atoms. Unfortunately, many interesting problems require simulations to be performed on much larger systems involving thousands of atoms or more. Consequently, more efficient methods are urgently needed, and a lot of effort has been spent on the development of a large variety of potentials enabling simulations with significantly extended time and length scales. Most commonly, these potentials are based on physically motivated functional forms and thus perform very well for the applications they have been designed for. On the other hand, they are often highly system-specific and thus cannot easily be transferred from one system to another. Moreover, their numerical accuracy is restricted by the intrinsic limitations of the imposed functional forms. In recent years, several novel types of potentials have emerged, which are not based on physical considerations. Instead, they aim to reproduce a set of reference electronic structure data as accurately as possible by using very general and flexible functional forms. In this review we will survey a number of these methods. While they differ in the choice of the employed mathematical functions, they all have in common that they provide high-quality potential-energy surfaces, while the efficiency is comparable to conventional empirical potentials. It has been demonstrated that in many cases these potentials now offer a very interesting new approach to study complex systems with hitherto unreached accuracy.

  9. Analytic models of plausible gravitational lens potentials

    SciTech Connect

    Baltz, Edward A.; Marshall, Phil; Oguri, Masamune E-mail: pjm@physics.ucsb.edu

    2009-01-15

    Gravitational lenses on galaxy scales are plausibly modelled as having ellipsoidal symmetry and a universal dark matter density profile, with a Sersic profile to describe the distribution of baryonic matter. Predicting all lensing effects requires knowledge of the total lens potential: in this work we give analytic forms for that of the above hybrid model. Emphasising that complex lens potentials can be constructed from simpler components in linear combination, we provide a recipe for attaining elliptical symmetry in either projected mass or lens potential. We also provide analytic formulae for the lens potentials of Sersic profiles for integer and half-integer index. We then present formulae describing the gravitational lensing effects due to smoothly-truncated universal density profiles in cold dark matter model. For our isolated haloes the density profile falls off as radius to the minus fifth or seventh power beyond the tidal radius, functional forms that allow all orders of lens potential derivatives to be calculated analytically, while ensuring a non-divergent total mass. We show how the observables predicted by this profile differ from that of the original infinite-mass NFW profile. Expressions for the gravitational flexion are highlighted. We show how decreasing the tidal radius allows stripped haloes to be modelled, providing a framework for a fuller investigation of dark matter substructure in galaxies and clusters. Finally we remark on the need for finite mass halo profiles when doing cosmological ray-tracing simulations, and the need for readily-calculable higher order derivatives of the lens potential when studying catastrophes in strong lenses.

  10. Analytic Models of Plausible Gravitational Lens Potentials

    SciTech Connect

    Baltz, Edward A.; Marshall, Phil; Oguri, Masamune

    2007-05-04

    Gravitational lenses on galaxy scales are plausibly modeled as having ellipsoidal symmetry and a universal dark matter density profile, with a Sersic profile to describe the distribution of baryonic matter. Predicting all lensing effects requires knowledge of the total lens potential: in this work we give analytic forms for that of the above hybrid model. Emphasizing that complex lens potentials can be constructed from simpler components in linear combination, we provide a recipe for attaining elliptical symmetry in either projected mass or lens potential.We also provide analytic formulae for the lens potentials of Sersic profiles for integer and half-integer index. We then present formulae describing the gravitational lensing effects due to smoothly-truncated universal density profiles in cold dark matter model. For our isolated haloes the density profile falls off as radius to the minus fifth or seventh power beyond the tidal radius, functional forms that allow all orders of lens potential derivatives to be calculated analytically, while ensuring a non-divergent total mass. We show how the observables predicted by this profile differ from that of the original infinite-mass NFW profile. Expressions for the gravitational flexion are highlighted. We show how decreasing the tidal radius allows stripped haloes to be modeled, providing a framework for a fuller investigation of dark matter substructure in galaxies and clusters. Finally we remark on the need for finite mass halo profiles when doing cosmological ray-tracing simulations, and the need for readily-calculable higher order derivatives of the lens potential when studying catastrophes in strong lenses.

  11. Analysis of potential helicopter vibration reduction concepts

    NASA Technical Reports Server (NTRS)

    Landgrebe, A. J.; Davis, M. W.

    1985-01-01

    Results of analytical investigations to develop, understand, and evaluate potential helicopter vibration reduction concepts are presented in the following areas: identification of the fundamental sources of vibratory loads, blade design for low vibration, application of design optimization techniques, active higher harmonic control, blade appended aeromechanical devices, and the prediction of vibratory airloads. Primary sources of vibration are identified for a selected four-bladed articulated rotor operating in high speed level flight. The application of analytical design procedures and optimization techniques are shown to have the potential for establishing reduced vibration blade designs through variations in blade mass and stiffness distributions, and chordwise center-of-gravity location.

  12. Effects of electron emission on sheath potential

    NASA Astrophysics Data System (ADS)

    Dow, Ansel; Khrabrov, Alexander; Kaganovich, Igor; Schamis, Hanna

    2015-11-01

    We investigate the potential profile of a sheath under the influence of surface electron emission. The plasma and sheath profiles are simulated using the Large Scale Plasma (LSP) particle-in-cell code. Using one dimensional models we corroborate the analytical relationship between sheath potential and plasma electron and emitted electron temperatures derived earlier. This work was made possible by funding from the Department of Energy for the Summer Undergraduate Laboratory Internship (SULI) program. This work is supported by the US DOE Contract No. DE-AC02-09CH11466.

  13. Pattern visual evoked potentials in hyperthyroidism.

    PubMed Central

    Mitchell, K W; Wood, C M; Howe, J W

    1988-01-01

    Pattern reversal visual evoked potentials (VEPs) have been elicited in 16 female hyperthyroid patients before and after treatment and compared with those from a similar group of age and sex matched control subjects. No effect on latency was seen, and although larger amplitude values were noted in the thyrotoxic group these too were not significant. We would conclude that hyperthyroidism per se has little effect on the pattern reversal VEP, and any observed effect on these potentials is probably due to other factors. PMID:3415945

  14. Comparative evolution: latent potentials for anagenetic advance.

    PubMed Central

    Stebbins, G L; Hartl, D L

    1988-01-01

    One of the principles that has emerged from experimental evolutionary studies of microorganisms is that polymorphic alleles or new mutations can sometimes possess a latent potential to respond to selection in different environments, although the alleles may be functionally equivalent or disfavored under typical conditions. We suggest that such responses to selection in microorganisms serve as experimental models of evolutionary advances that occur over much longer periods of time in higher organisms. We propose as a general evolutionary principle that anagenic advances often come from capitalizing on preexisting latent selection potentials in the presence of novel ecological opportunity. PMID:3293050

  15. Model potential calculations of lithium transitions.

    NASA Technical Reports Server (NTRS)

    Caves, T. C.; Dalgarno, A.

    1972-01-01

    Semi-empirical potentials are constructed that have eigenvalues close in magnitude to the binding energies of the valence electron in lithium. The potentials include the long range polarization force between the electron and the core. The corresponding eigenfunctions are used to calculate dynamic polarizabilities, discrete oscillator strengths, photoionization cross sections and radiative recombination coefficients. A consistent application of the theory imposes a modification on the transition operator, but its effects are small for lithium. The method presented can be regarded as a numerical generalization of the widely used Coulomb approximation.

  16. Simple analytic potentials for linear ion traps

    NASA Technical Reports Server (NTRS)

    Janik, G. R.; Prestage, J. D.; Maleki, L.

    1990-01-01

    A simple analytical model was developed for the electric and ponderomotive (trapping) potentials in linear ion traps. This model was used to calculate the required voltage drive to a mercury trap, and the result compares well with experiments. The model gives a detailed picture of the geometric shape of the trapping potential and allows an accurate calculation of the well depth. The simplicity of the model allowed an investigation of related, more exotic trap designs which may have advantages in light-collection efficiency.

  17. Sigma-nucleus potential in A=28.

    PubMed

    Noumi, H; Saha, P K; Abe, D; Ajimura, S; Aoki, K; Bhang, H C; Endo, T; Fujii, Y; Fukuda, T; Guo, H C; Imai, K; Hashimoto, O; Hotchi, H; Kim, E H; Kim, J H; Kishimoto, T; Krutenkova, A; Maeda, K; Nagae, T; Nakamura, M; Outa, H; Sekimoto, M; Saito, T; Sakaguchi, A; Sato, Y; Sawafta, R; Shimizu, Y; Takahashi, T; Tang, L; Tamura, H; Tanida, K; Watanabe, T; Xia, H H; Zhou, S H; Zhu, L H; Zhu, X F

    2002-08-12

    We have studied the (pi(-),K+) reaction on a silicon target to investigate the sigma-nucleus potential. The inclusive spectrum was measured at a beam momentum of 1.2 GeV/c with an energy resolution of 3.3 MeV (FWHM) by employing the superconducting kaon spectrometer system. The spectrum was compared with theoretical calculations within the framework of the distorted-wave impulse approximation, which demonstrates that a strongly repulsive sigma-nucleus potential with a nonzero size of the imaginary part reproduces the observed spectrum. PMID:12190516

  18. Nanoparticle interaction potentials constructed by multiscale computation

    NASA Astrophysics Data System (ADS)

    Lee, Cheng K.; Hua, Chi C.

    2010-06-01

    The van der Waals (vdW) potentials governing macroscopic objects have long been formulated in the context of classical theories, such as Hamaker's microscopic theory and Lifshitz's continuum theory. This work addresses the possibility of constructing the vdW interaction potentials of nanoparticle species using multiscale simulation schemes. Amorphous silica nanoparticles were considered as a benchmark example for which a series of (SiO2)n (n being an integer) has been systematically surveyed as the potential candidates of the packing units that reproduce known bulk material properties in atomistic molecular dynamics simulations. This strategy led to the identification of spherical Si6O12 molecules, later utilized as the elementary coarse-grained (CG) particles to compute the pair interaction potentials of silica nanoparticles ranging from 0.62 to 100 nm in diameter. The model nanoparticles so built may, in turn, serve as the children CG particles to construct nanoparticles assuming arbitrary sizes and shapes. Major observations are as follows. The pair interaction potentials for all the investigated spherical silica nanoparticles can be cast into a semiempirical, generalized Lennard-Jones 2α-α potential (α being a size-dependent, large integral number). In its reduced form, we discuss the implied universalities for the vdW potentials governing a certain range of amorphous nanoparticle species as well as how thermodynamic transferability can be fulfilled automatically. In view of future applications with colloidal suspensions, we briefly evaluated the vdW potential in the presence of a "screening" medium mimicking the effects of electrical double layers or grafting materials atop the nanoparticle core. The general observations shed new light on strategies to attain a microscopic control over interparticle attractions. In future perspectives, the proposed multiscale computation scheme shall help bridge the current gap between the modeling of polymer chains and

  19. Therapeutic potential of cannabis-related drugs.

    PubMed

    Alexander, Stephen P H

    2016-01-01

    In this review, I will consider the dual nature of Cannabis and cannabinoids. The duality arises from the potential and actuality of cannabinoids in the laboratory and clinic and the 'abuse' of Cannabis outside the clinic. The therapeutic areas currently best associated with exploitation of Cannabis-related medicines include pain, epilepsy, feeding disorders, multiple sclerosis and glaucoma. As with every other medicinal drug of course, the 'trick' will be to maximise the benefit and minimise the cost. After millennia of proximity and exploitation of the Cannabis plant, we are still playing catch up with an understanding of its potential influence for medicinal benefit. PMID:26216862

  20. [Age changes in early somatosensory evoked potentials].

    PubMed

    Strenge, H

    1986-06-01

    There are characteristic age-related changes in the cervical and early cortical somatosensory potentials evoked by electrical stimulation of the median nerve. At an age of 40 to 50 years the latencies of the potential components and the transit times start increasing progressively. Moreover, there is an attenuation of the cervical and an enhancement of the cortical components with age. Considering the presumed neuronal basis of the bioelectric phenomena the changes are discussed in connection with aging processes of the spinal ganglion cells, cortical pyramidal cells and the locus coeruleus. PMID:3017682

  1. Origin of auroral electric potential structures

    NASA Astrophysics Data System (ADS)

    Chiu, Y. T.

    Available observational data and theoretical models of the formation of auroral electric potential structures are reviewed. It is shown that the principle of arc formation in the aurora can also be applied to other geomagnetic configurations, in order to construct a comprehensive theory of discrete auroral arcs. According to the theory, the completion of the field-aligned current circuit in the aurora can lead to downward parallel electric fields in the return current from the central region of discrete arc potential. It is pointed out that evidence for downward parallel electric field signatures has been collected within the last year.

  2. Potential energy function for the hydroperoxyl radical

    SciTech Connect

    Lemon, W.J.; Hase, W.L.

    1987-03-12

    A switching function formalism is used to derive an analytic potential energy surface for the O + OH in equilibrium HO/sub 2/ in equilibrium H + O/sub 2/ reactive system. Both experimental and ab initio data are used to derive parameters for the potential energy surface. Trajectory calculations for highly excited HO/sub 2/ are performed on this surface. From these trajectories quasi-periodic eigentrajectories are found for vibrational levels near the HO/sub 2/ dissociation threshold with small amounts of quanta in the OH stretch mode and large amounts of quanta in the OO stretch mode.

  3. Kähler potentials for Planck inflation

    SciTech Connect

    Roest, Diederik; Scalisi, Marco; Zavala, Ivonne E-mail: m.scalisi@rug.nl

    2013-11-01

    We assess which Kähler potentials in supergravity lead to viable single-field inflationary models that are consistent with Planck. We highlight the role of symmetries, such as shift, Heisenberg and supersymmetry, in these constructions. Also the connections to string theory are pointed out. Finally, we discuss a supergravity model for arbitrary inflationary potentials that is suitable for open string inflation and generalise it to the case of closed string inflation. Our model includes the recently discussed supergravity reformulation of the Starobinsky model of inflation as well as an interesting alternative with comparable predictions.

  4. Economic Energy Savings Potential in Federal Buildings

    SciTech Connect

    Brown, Daryl R.; Dirks, James A.; Hunt, Diane M.

    2000-09-04

    The primary objective of this study was to estimate the current life-cycle cost-effective (i.e., economic) energy savings potential in Federal buildings and the corresponding capital investment required to achieve these savings, with Federal financing. Estimates were developed for major categories of energy efficiency measures such as building envelope, heating system, cooling system, and lighting. The analysis was based on conditions (building stock and characteristics, retrofit technologies, interest rates, energy prices, etc.) existing in the late 1990s. The potential impact of changes to any of these factors in the future was not considered.

  5. Environmental Perchlorate Exposure: Potential Adverse Thyroid Effects

    PubMed Central

    Leung, Angela M.; Pearce, Elizabeth N.; Braverman, Lewis E.

    2014-01-01

    Purpose of review This review will present a general overview of the sources, human studies, and proposed regulatory action regarding environmental perchlorate exposure. Recent findings Some recent studies have reported significant associations between urinary perchlorate concentrations, thyroid dysfunction, and decreased infant IQ in groups who would be particularly susceptible to perchlorate effects. An update regarding the recent proposed regulatory actions and potential costs surrounding amelioration of perchlorate contamination is provided. Summary The potential adverse thyroidal effects of environmental perchlorate exposure remain controversial, and further research is needed to further define its relationship to human health among pregnant and lactating women and their infants. PMID:25106002

  6. Q-balls in flat potentials

    SciTech Connect

    Copeland, Edmund J.; Tsumagari, Mitsuo I.

    2009-07-15

    We study the classical and absolute stability of Q-balls in scalar field theories with flat potentials arising in both gravity-mediated and gauge-mediated models. We show that the associated Q-matter formed in gravity-mediated potentials can be stable against decay into their own free particles as long as the coupling constant of the nonrenormalizable term is small, and that all of the possible three-dimensional Q-ball configurations are classically stable against linear fluctuations. Three-dimensional gauge-mediated Q-balls can be absolutely stable in the thin-wall limit, but are completely unstable in the thick-wall limit.

  7. A laboratory investigation of potential double layers

    NASA Technical Reports Server (NTRS)

    Leung, Philip

    1987-01-01

    In a triple plasma device, the injection of electron current from the source chamber to the target chamber causes the formation of a potential double layer. At a low current density, the space charge of the injected current produces a virtual cathode-type potential double layer. This double layer is stable, and various wave instabilities are observed to associate with this double layer. As the current density is increased, the double layer becomes unstable, and a moving double layer results. As the current density is increased further, the enhanced ionization causes the neutralization of the space charge of the electron beam, and the beam plasma discharge is ignited.

  8. A laboratory investigation of potential double layers

    NASA Technical Reports Server (NTRS)

    Leung, Philip

    1987-01-01

    In a triple plasma device, the injection of electron current from the source chamber to the target chamber causes the formation of a potential double layer. At a low current density, the space charge of the injected current produces a virtual cathode-type potential double layer. This double layer is stable and various wave instabilities are observed to associate with this double layer. As the current density is increased, the double layer becomes unstable and a moving double layer results. As the current density is increased further, the enhanced ionization causes the neutralization of the space charge of the electron beam and the 'beam plasma discharge' is ignited.

  9. Potential roles of telocytes in lung diseases.

    PubMed

    Shi, Lin; Dong, Nian; Chen, Chengshui; Wang, Xiangdong

    2016-07-01

    Telocytes (TCs) are a unique type of interstitial cells with specific, extremely long prolongations named telopodes (Tps), as shown by immune-positive staining against CD34, c-kit and vimentin. They were found in many organs of mammals, with potential biological functions, including the trachea and lung, even though the exact function remains unclear. Here, we give a historical overview of the TCs research field and summarize the latest findings associated with TCs, with a special focus on the recent progress about TCs specific gene and protein profiles that has been made in understanding that TCs may play a potential, but important, role in the pathogenesis of lung diseases. PMID:26855021

  10. Correlation of action potentials in adjacent neurons

    NASA Astrophysics Data System (ADS)

    Shneider, M. N.; Pekker, M.

    2015-12-01

    A possible mechanism for the synchronization of action potential propagation along a bundle of neurons (ephaptic coupling) is considered. It is shown that this mechanism is similar to the salutatory conduction of the action potential between the nodes of Ranvier in myelinated axons. The proposed model allows us to estimate the scale of the correlation, i.e., the distance between neurons in the nervous tissue, wherein their synchronization becomes possible. The possibility for experimental verification of the proposed model of synchronization is discussed.

  11. Potentially Ineffective Care: Time for Earnest Reexamination

    PubMed Central

    Jackson, William L.; Sales, Joseph F.

    2014-01-01

    The rising costs and suboptimal quality throughout the American health care system continue to invite critical inquiry, and practice in the intensive care unit setting is no exception. Due to their relatively large impact, outcomes and costs in critical care are of significant interest to policymakers and health care administrators. Measurement of potentially ineffective care has been proposed as an outcome measure to evaluate critical care delivery, and the Patient Protection and Affordable Care Act affords the opportunity to reshape the care of the critically ill. Given the impetus of the PPACA, systematic formal measurement of potentially ineffective care and its clinical, economic, and societal impact merits timely reconsideration. PMID:24804088

  12. Fly Ash Characteristics and Carbon Sequestration Potential

    SciTech Connect

    Palumbo, Anthony V.; Amonette, James E.; Tarver, Jana R.; Fagan, Lisa A.; McNeilly, Meghan S.; Daniels, William L.

    2007-07-20

    Concerns for the effects of global warming have lead to an interest in the potential for inexpensive methods to sequester carbon dioxide (CO2). One of the proposed methods is the sequestration of carbon in soil though the growth of crops or forests.4,6 If there is an economic value placed on sequestration of carbon dioxide in soil there may be an an opportunity and funding to utilize fly ash in the reclamation of mine soils and other degraded lands. However, concerns associated with the use of fly ash must be addressed before this practice can be widely adopted. There is a vast extent of degraded lands across the world that has some degree of potential for use in carbon sequestration. Degraded lands comprise nearly 2 X 109 ha of land throughout the world.7 Although the potential is obviously smaller in the United States, there are still approximately 4 X 106 ha of degraded lands that previously resulted from mining operations14 and an additional 1.4 X 108 ha of poorly managed lands. Thus, according to Lal and others the potential is to sequester approximately 11 Pg of carbon over the next 50 years.1,10 The realization of this potential will likely be dependent on economic incentives and the use of soil amendments such as fly ash. There are many potential benefits documented for the use of fly ash as a soil amendment. For example, fly ash has been shown to increase porosity, water-holding capacity, pH, conductivity, and dissolved SO42-, CO32-, HCO3-, Cl- and basic cations, although some effects are notably decreased in high-clay soils.8,13,9 The potential is that these effects will promote increased growth of plants (either trees or grasses) and result in greater carbon accumulation in the soil than in untreated degraded soils. This paper addresses the potential for carbon sequestration in soils amended with fly ash and examines some of the issues that should be considered in planning this option. We describe retrospective studies of soil carbon accumulation on

  13. Generalized Potential of Adult Neural Stem Cells

    NASA Astrophysics Data System (ADS)

    Clarke, Diana L.; Johansson, Clas B.; Wilbertz, Johannes; Veress, Biborka; Nilsson, Erik; Karlström, Helena; Lendahl, Urban; Frisén, Jonas

    2000-06-01

    The differentiation potential of stem cells in tissues of the adult has been thought to be limited to cell lineages present in the organ from which they were derived, but there is evidence that some stem cells may have a broader differentiation repertoire. We show here that neural stem cells from the adult mouse brain can contribute to the formation of chimeric chick and mouse embryos and give rise to cells of all germ layers. This demonstrates that an adult neural stem cell has a very broad developmental capacity and may potentially be used to generate a variety of cell types for transplantation in different diseases.

  14. On the origins of dorsal root potentials.

    PubMed

    LLOYD, D P C; McINTYRE, A K

    1949-03-20

    The "dorsal root potential" consists of five successive deflections designated for convenience, D.R.I, II, III, IV, and V. Of these, D.R.V alone constitutes the dorsal root potential of prior description. A study has been made of the general properties of those deflections not previously described. Dorsal root potentials are electrotonic extensions into the extramedullary root segment, the result of electrical interactions within the cord comparable to those that have been studied in peripheral nerve. Although the anatomical and electrical conditions of interaction are infinitely more complex in the cord than in nerve, it is seen that the fact of parallel distribution of primary afferent fibers pertaining to neighboring dorsal roots provides a sufficient anatomical basis for qualitative analysis in the first approximation of dorsal root potentials. An extension of the theory of interaction between neighboring nerve fibers has been made to include an especial case of interaction between fibers orientated at right angles to one another. The predictions have been tested in a nerve model and found correct. Given this elaboration, and the stated anatomical propositions, existing knowledge of interaction provides an adequate theoretical basis for an elementary understanding of dorsal root potentials. The study of general properties and the analysis of dorsal root potentials have led to the formulation of certain conclusions that follow. D.R.I, II, and III record the electrotonic spread of polarization resulting from the external field of impulses conducted in the intramedullary segment and longitudinal trajects of primary afferent fibers. D.R.IV arises in part as the result of activity in primary afferent fibers, and in part as the result of activity in secondary neurons. In either case the mode of production is the same, and the responsible agent is residual negativity in the active collaterals, or, more precisely, the external field of current flow about the

  15. Structural origins of redox potentials in Fe-S proteins: electrostatic potentials of crystal structures.

    PubMed Central

    Swartz, P D; Beck, B W; Ichiye, T

    1996-01-01

    Redox potentials often differ dramatically for homologous proteins that have identical redox centers. For two types of iron-sulfur proteins, the rubredoxins and the high-potential iron-sulfur proteins (HiPIPs), no structural explanations for these differences have been found. We calculated the classical electrostatic potential at the redox site using static crystal structures of four rubredoxins and four HiPIPs to identify important structural determinants of their redox potentials. The contributions from just the backbone and polar side chains are shown to explain major features of the experimental redox potentials. For instance, in the rubredoxins, the presence of Val 44 versus Ala 44 causes a backbone shift that explains a approximately 50 mV lower redox potential in one of the four rubredoxins. This result is consistent with experimental redox potentials of five additional rubredoxins with known sequence. Also, we attribute the unusually lower redox potentials of two of the HiPIPs studied to a less positive electrostatic environment around their redox sites. Finally, molecular dynamics simulations of solvent around static rubredoxin crystal structures indicate that water alone is a major factor in dampening the contribution of charged side chains, in accord with experiments showing that mutations of surface charges produce relatively little effect on redox potentials. Images FIGURE 1 FIGURE 3 FIGURE 4 FIGURE 5 FIGURE 6 PMID:8968568

  16. Kindergarten Readiness Skills: Predictors of Academic Potential

    ERIC Educational Resources Information Center

    Rawlings, Jennifer

    2011-01-01

    The purpose of this study was to determine the relationship between school readiness skills as measured by the Missouri KIDS and academic potential in reading and math as measured by the scores on the CTP4 in grades 2-4 in a private, independent school. This study identified which school readiness skills most accurately predict the need for…

  17. Effective Potential in Noncommutative BTZ Black Hole

    NASA Astrophysics Data System (ADS)

    Sadeghi, Jafar; Shajiee, Vahid Reza

    2016-02-01

    In this paper, we investigated the noncommutative rotating BTZ black hole and showed that such a space-time is not maximally symmetric. We calculated effective potential for the massive and the massless test particle by geodesic equations, also we showed effect of non-commutativity on the minimum mass of BTZ black hole.

  18. Implicit Assumptions in High Potentials Recruitment

    ERIC Educational Resources Information Center

    Posthumus, Jan; Bozer, Gil; Santora, Joseph C.

    2016-01-01

    Purpose: Professionals of human resources (HR) use different criteria in practice than they verbalize. Thus, the aim of this research was to identify the implicit criteria used for the selection of high-potential employees in recruitment and development settings in the pharmaceutical industry. Design/methodology/approach: A semi-structured…

  19. Potentially hazardous waste produced at home

    PubMed Central

    2013-01-01

    Background The purpose of this study was to identify the sources of waste generation household consisting of biological material and to investigate the knowledge presented by those responsible for the generation of waste in the home environment on the potential health risk human and environmental. Method It is a quantitative survey performed in Parque Capuava, Santo André (SP). The questionnaire was administered by the community employers and nursing students during the consultation with nursing supervision through interview question/answer. The exclusion criteria were patients who were not in the area served by the Basic Health Unit which covers the area of Pq Capuava. The sample was consisted of 99 persons and the data collection a questionnaire was used. Results We observed that 63.3% of people said to use disposables, with the majority (58.7%) of these use the public collection as the final destination of these materials. It was reported that 73.7% of those surveyed reported having knowledge about the risk of disease transmission. Public awareness of the importance of proper packaging and disposal of potentially hazardous household waste may contribute significantly to the preservation of human and environmental health and this procedure can be performed and supervised by professional nurses. Conclusion We suggest implementation of workshops for community health workers and the general population in order to enhance their knowledge about the storage and disposal of potentially infectious waste generated at home, thereby reducing the potential risk of disease transmission by improper management. PMID:23806043

  20. The Kid Underneath: Discovering Hidden Potential

    ERIC Educational Resources Information Center

    Olive, Edna C.

    2005-01-01

    In this article, a youth who is transformed from a troublemaker to a model student offers his advice on what it takes to reclaim kids like himself. Sections include: (1) The Outside Will; (2) Will Unfolding; (3) The Transition; (4) Potential Realized; (5) A Conversation with the Inside Kid; and (6) Suggestions from the Inside Kid.

  1. Gravitational potential: real-life results

    NASA Astrophysics Data System (ADS)

    Mungan, Carl E.

    2016-01-01

    The equilibrium surface of a large body of water is a gravitational equipotential. However, that does not imply that in a local region of increased gravitational field g the height h of the water surface will be lower to keep the potential gh constant, in contrast to a recent claim to that effect.

  2. Marketing potential of advanced breeding clones

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The accumulation of reducing sugars during cold storage of potato tubers is a serious and costly problem for producers and processors. The degree to which cultivars accumulate reducing sugars during storage determines their processing and market potential. Cultivars or advanced breeding lines with...

  3. Maximizing the nutritional potential of potato

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As the most eaten vegetable in the United States, potatoes have tremendous potential to be a valuable source of vitamins and phytonutrients in the diet. Potato is the only tuber amongst all the world’s major food crops, most of which are grains or roots. Potatoes are already known to be a good sour...

  4. Auditory and visual evoked potentials during hyperoxia

    NASA Technical Reports Server (NTRS)

    Smith, D. B. D.; Strawbridge, P. J.

    1974-01-01

    Experimental study of the auditory and visual averaged evoked potentials (AEPs) recorded during hyperoxia, and investigation of the effect of hyperoxia on the so-called contingent negative variation (CNV). No effect of hyperoxia was found on the auditory AEP, the visual AEP, or the CNV. Comparisons with previous studies are discussed.

  5. Exploiting the Potential Differences in Pasture Grasses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Temperate grasses grown for pasture in Wisconsin exhibit a range of chemical and physical characteristics that influence their utilization by grazing cattle. Potential intake of all grasses declines with maturity due to decreasing cell wall digestiblity, but the leaves and stems of orchardgrass and...

  6. Introducing the Action Potential to Psychology Students

    ERIC Educational Resources Information Center

    Simon-Dack, Stephanie L.

    2014-01-01

    For this simple active learning technique for teaching, students are assigned "roles" and act out the process of the action potential (AP), including the firing threshold, ion-specific channels for ions to enter and leave the cell, diffusion, and the refractory period. Pre-post test results indicated that students demonstrated increased…

  7. Quantifying the transmission potential of pandemic influenza

    NASA Astrophysics Data System (ADS)

    Chowell, Gerardo; Nishiura, Hiroshi

    2008-03-01

    This article reviews quantitative methods to estimate the basic reproduction number of pandemic influenza, a key threshold quantity to help determine the intensity of interventions required to control the disease. Although it is difficult to assess the transmission potential of a probable future pandemic, historical epidemiologic data is readily available from previous pandemics, and as a reference quantity for future pandemic planning, mathematical and statistical analyses of historical data are crucial. In particular, because many historical records tend to document only the temporal distribution of cases or deaths (i.e. epidemic curve), our review focuses on methods to maximize the utility of time-evolution data and to clarify the detailed mechanisms of the spread of influenza. First, we highlight structured epidemic models and their parameter estimation method which can quantify the detailed disease dynamics including those we cannot observe directly. Duration-structured epidemic systems are subsequently presented, offering firm understanding of the definition of the basic and effective reproduction numbers. When the initial growth phase of an epidemic is investigated, the distribution of the generation time is key statistical information to appropriately estimate the transmission potential using the intrinsic growth rate. Applications of stochastic processes are also highlighted to estimate the transmission potential using similar data. Critically important characteristics of influenza data are subsequently summarized, followed by our conclusions to suggest potential future methodological improvements.

  8. MARKETING POTENTIAL OF ADVANCED BREEDING CLONES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The accumulation of reducing sugars during cold storage of potato tubers is a serious and costly problem for producers and processors. The degree to which cultivars accumulate reducing sugars during storage determines their processing and market potential. Cultivars or advanced breeding lines with...

  9. Functionalized carbon nanotubes for potential medicinal applications

    PubMed Central

    Zhang, Yi; Bai, Yuhong; Yan, Bing

    2016-01-01

    Functionalized carbon nanotubes display unique properties that enable a variety of medicinal applications, including the diagnosis and treatment of cancer, infectious diseases and central nervous system disorders, and applications in tissue engineering. These potential applications are particularly encouraged by their ability to penetrate biological membranes and relatively low toxicity. PMID:20451656

  10. General Potential Theory of Arbitrary Wing Section

    NASA Technical Reports Server (NTRS)

    Theodorsen, T; Garrick, I E

    1934-01-01

    This report gives the exact treatment of the problem of determining the 2-dimensional potential flow around wing sections of any type. The treatment is based directly on the solution of this problem as advanced by Theodorsen in NACA-TR-411. The problem condenses into the compact form of an integral equation capable of yielding numerical solutions by a direct process.

  11. Evaluating Potential Health Risks in Relocatable Classrooms.

    ERIC Educational Resources Information Center

    Katchen, Mark; LaPierre, Adrienne; Charlin, Cary; Brucker, Barry; Ferguson, Paul

    2001-01-01

    Only limited data exist describing potential exposures to chemical and biological agents when using portable classrooms or outlining how to assess and reduce associated health risks. Evaluating indoor air quality involves examining ventilating rates, volatile organic compounds, and microbiologicals. Open communication among key stakeholders is…

  12. State and Local Revenue Potential 1972.

    ERIC Educational Resources Information Center

    Quindry, Kenneth E.; Engels, Richard A.

    In the sixth annual Southern Regional Education Board analysis of state and local revenue potential, the authors suggest that 1972 tax collections, here reported, represent a kind of watershed in revenue availability. The economic boom over the last two years has substantially removed the need for many states to consider new revenue measures. In…

  13. Aerospace Power Technology for Potential Terrestrial Applications

    NASA Technical Reports Server (NTRS)

    Lyons, Valerie J.

    2012-01-01

    Aerospace technology that is being developed for space and aeronautical applications has great potential for providing technical advances for terrestrial power systems. Some recent accomplishments arising from activities being pursued at the National Aeronautics and Space Administration (NASA) Centers is described in this paper. Possible terrestrial applications of the new aerospace technology are also discussed.

  14. FELS FOUNDATION PROJECT FOR DEVELOPING YOUTH POTENTIAL.

    ERIC Educational Resources Information Center

    BAIR, ROBERT A.; AND OTHERS

    THE OPERATION OF THE FELS FOUNDATION PROJECT FOR DEVELOPING YOUTH POTENTIAL IN HANFORD, CALIFORNIA, IS DESCRIBED. OF GENERAL CONCERN WAS THE PREPARATION OF CULTURALLY DEPRIVED CHILDREN FOR SCHOOL EXPERIENCES AND FOR FUTURE EMPLOYMENT. A MAJOR GOAL WAS TO IMPROVE THE SELF-IMAGE OF THE CHILDREN AND TO ASSIST THE PARENTS AND CHILDREN IN PROVIDING…

  15. Potential Energy Sources Pose Mining Problem

    ERIC Educational Resources Information Center

    Chemical and Engineering News, 1974

    1974-01-01

    Summarizes the discussions of a Division of Industrial and Engineering Chemistry symposium on solids handling for synthetic fuels production. Included is a description of technical difficulties with the use of coal seams and deposits of oil shale and oil sand as potential sources of fuel. (CC)

  16. Broiler cake potential to emit ammonia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Spatial differences for ammonia (NH3) flux from litter are evident within broiler houses especially when considering friable litter and caked surfaces. The objectives of this study were to quantify NH3 generation potential between different sources of cake (two separate farms having variable length...

  17. Real and potential nickel hydrogen superiority

    NASA Technical Reports Server (NTRS)

    Betz, F. E.

    1983-01-01

    Events from the development and orbital flight experience with a nickel hydrogen battery are described. The events highlight characteristics of nickel hydrogen which afford superior capability in overcharge, overdischarge and state of charge evaluation, when compared to the nickel cadmium electrochemical system. Some developments in nickel hydrogen technology that provide the potential of furthering nickel hydrogen superiority for satellite applications are also discussed.

  18. Staging the Future--Potentializing the Self

    ERIC Educational Resources Information Center

    Bjerg, Helle

    2013-01-01

    This article frames a qualitative analysis of how a particular actualization of independent project work may be understood as a "pedagogy of potentialization" that relies on schooling the desire to learn as creation and (self-)transgression. The framework for analyzing school as an affective space draws on conceptualizations of affect,…

  19. Vector Potential, Electromagnetic Induction and "Physical Meaning"

    ERIC Educational Resources Information Center

    Giuliani, G.

    2010-01-01

    A forgotten experiment by Andre Blondel (1914) proves, as held on the basis of theoretical arguments in a previous paper, that the time variation of the magnetic flux is not the cause of the induced emf; the physical agent is instead the vector potential through the term [equation omitted] (when the induced circuit is at rest). The "good…

  20. Tendencies and Prospects in Building Educational Potential

    ERIC Educational Resources Information Center

    Avraamova, E. M.

    2010-01-01

    Global competition, which has become more acute with the onset of the world financial and economic crisis, is forcing countries to look for resources by means of which the crisis can be overcome and national economies will receive a new impetus of development. It is the growth of the educational potential that constitutes the component of the…

  1. Field investigation of rooting potential in sorghum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The differential influence of root systems on plant development under field conditions is very difficult. A field experiment was devised using three different row spacings (101,152 and 203 cm ) to screen sorghum germplasm for rooting potential based on the relative ability to explore additional soil...

  2. Screening Spouse Abusers for Child Abuse Potential.

    ERIC Educational Resources Information Center

    Milner, Joel S.; Gold, Ruth G.

    1986-01-01

    Investigated the ability of the Child Abuse Potential Inventory to screen for child abuse in a group of spouse abusers. The completed, valid protocols revealed that 36.5 percent of the spouse abusers had elevated child abuse scores, while only 9.1 percent of the nonabusers had elevated abuse scores. (Author/BL)

  3. The Potential of Perspectivism for Science Education

    ERIC Educational Resources Information Center

    Pearce, Jacob V.

    2013-01-01

    Many science teachers are presented with the challenge of characterizing science as a dynamic, human endeavour. Perspectivism, as a hermeneutic philosophy of science, has the potential to be a learning tool for teachers as they elucidate the complex nature of science. Developed earlier by Nietzsche and others, perspectivism has recently re-emerged…

  4. Health Promoting Schools: Consensus, Strategies, and Potential

    ERIC Educational Resources Information Center

    Macnab, Andrew J.; Gagnon, Faith A.; Stewart, Donald

    2014-01-01

    Purpose: The purpose of this paper is to summarize a consensus statement generated on the current challenges, strategies, and potential of health promoting schools (HPS) at a 2011 colloquium at the Stellenbosch Institute for Advanced Study where 40 people from five continents came together to share their global and regional experience surrounding…

  5. SENSORY EVOKED POTENTIALS: MEASURES OF NEUROTOXICITY

    EPA Science Inventory

    There is a need for tests of sensory function to be incorporated in laboratory and toxicity testing. t is clear that sensory dysfunction may frequently occur, but go undetected, in standard animal toxicological testing protocols. ensory evoked potential technology can be employed...

  6. Molecular Electrostatic Potentials from Invariom Point Charges.

    PubMed

    Wandtke, Claudia M; Lübben, Jens; Dittrich, Birger

    2016-07-18

    A set of look-up point charges for generating molecular electrostatic potentials is provided. The set relies on atom classification of the invariom database, which has already been applied to assign aspherical scattering factors in single-crystal X-ray diffraction. The focus of the investigation is on improving the accuracy of electrostatic potentials calculated by using tabulated point charges. In this respect, the performance of invariom point charges is compared with 1) those from a restrained fit to the electrostatic potential directly following quantum-chemical DFT computations, 2) semi-empirical AM1-bcc charges, and 3) conceptually similar TPACM4 look-up charges. Invariom classification gives charges that perform better than those from TPACM4, although tabulated charges remain inferior to those from molecule-specific computations. Point-charge electrostatic potentials also agree favorably with those from charge-density studies on the basis of X-ray experiments, without requiring the considerable effort of the latter. PMID:26999276

  7. Chemical potential beyond the quasiparticle mean field

    SciTech Connect

    Dinh Dang, N.; Hung, N. Quang

    2010-03-15

    The effects of quantal and thermal fluctuations beyond the BCS quasiparticle mean field on the chemical potential are studied within a model, which consists of N particles distributed amongst {Omega} doubly folded equidistant levels interacting via a pairing force with parameter G. The results obtained at zero and finite temperatures T within several approaches, which include the fluctuations beyond the BCS theory, are compared with the exact results. The chemical potential, defined as the Lagrangian multiplier to preserve the average number of particles, is compared with the corresponding quantity, which includes the effect from fluctuations of particle and quasiparticle numbers beyond the BCS quasiparticle mean field. The analysis of the results shows that the latter differs significantly from the former as functions of G and T. The chemical potential loses its physical meaning in the system with a fixed number of particles or after eliminating quantal fluctuations of particle (quasiparticle) numbers by means of particle number projection. The validity of the criterion for the signature of the transition to Bose-Einstein condensation, which occurs in infinite systems when the chemical potential hits the bottom of the energy spectrum, is reexamined for the finite multilevel model.

  8. State and Local Revenue Potential, 1970.

    ERIC Educational Resources Information Center

    Quindry, Kenneth E.

    This report contains results of an extensive study into State and local tax revenue potentials for the 15 Southern Regional Education Board (SREB) States and presents quantitative data on the 50 State-local tax systems. Data set forth in the 35 statistical tables enable the researcher to compare his State's total tax revenues with those of each of…

  9. The space potential in the tokamak text

    SciTech Connect

    Yang, X.Z.; Zhang, B.Z.; Wootton, A.J.; Schoch, P.M.; Richards, B.; Baldwin, D.; Brower, D.L.; Castle, G.G.; Hazeltine, R.D.; Heard, J.W.; Hickok, R.L.; Li, W.L.; Lin, H.; McCool, S.C.; Simcic, V.J.; Ritz, C.P.; Yu, C.X. )

    1991-12-01

    A heavy ion beam probe has been used to measure the plasma space potential profiles in the tokamak TEXT (Nucl. Fusion Technol. {bold 1}, 479 (1981)). The Ohmic discharges studied were perturbed by externally produced resonant magnetic fields (an ergodic magnetic limiter or EML). Without these perturbations the plasma central potential is generally consistent with the value calculated from radial ion momentum balance, using experimental values of density and ion temperature and assuming a neoclassical poloidal rotation velocity. Exceptions to the agreement are found when operating with reduced plasma parameters. Possible reasons for this discrepancy are explored, in particular, the effects of intrinsic magnetic field fluctuations, and modifications to the self-consistent radial electric sheath. With the application of the EML fields the edge electric field and potential increase during periods of magnetic island overlap. A test particle calculation of electron transport shows increases in diffusivity also occur during periods of magnetic island overlap. These calculated changes in diffusivity are interpreted in terms of a stochastic layer width, which is itself used to predict a potential change for comparison with the experimental results.

  10. Mapping Potential Croplands in the United States

    NASA Astrophysics Data System (ADS)

    Lark, T. J.; Gibbs, H. K.

    2012-12-01

    There is a growing debate about land availability in the U.S., with some proponents of biofuels suggesting a nearly endless supply of land for production, while others claim we have already reached "peak land". Until now, however, there has been no comprehensive evaluation of the extent and location of uncultivated land suitable for crop production in the U.S. We created the first spatially-explicit database of Potentially Available Cropland (PAC) in the United States by fusing NASS's Cropland Data Layer with data from the U.S. Census and Census of Agriculture, Soil Survey Geographic (SSURGO) data, and databases of public, private, and protected areas, while implementing rule-based decisions derived from stakeholder interviews. We considered all potential cropland, including idle land, pastureland, and areas of turf lawn that could be used for production. We then used the output maps to estimate maximum production potential and associated carbon debt for the U.S. under a range of scenarios. Preliminary results suggest that fully cultivating all PAC could increase U.S. annual corn grain production by 16 - 48 % and more than double current U.S. vegetable production. However, several economic, social, and physical constraints as well as ecological tradeoffs limit the practical expansion onto these lands. Our results will provide needed inputs to project national and global agricultural production potential, constrain estimates of direct and indirect land use change, and inform agricultural and energy policy.

  11. Reader, Text, Translation, and Interpretive Potentials.

    ERIC Educational Resources Information Center

    Dollerup, Cay; And Others

    No matter what pains translators take to produce a target-language text "identical" to the source-language text, criticism and/or translation of an original literary work cannot be the same in different language communities. That translation may change potentialities in the textual experience is particularly obvious in literature with a strong…

  12. Wind energy in China: Estimating the potential

    NASA Astrophysics Data System (ADS)

    Yuan, Jiahai

    2016-07-01

    Persistent and significant curtailment has cast concern over the prospects of wind power in China. A comprehensive assessment of the production of energy from wind has identified grid-integrated wind generation potential at 11.9–14% of China's projected energy demand by 2030.

  13. Transferrin: structure, function and potential therapeutic actions.

    PubMed

    Gomme, Peter T; McCann, Karl B; Bertolini, Joseph

    2005-02-15

    There are many proteins that can multi-task. Transferrin, widely known as an iron-binding protein, is one such example of a multi-tasking protein. In this review, the multiple biological actions of transferrin, including its growth and cytoprotective activities, are discussed with the view of highlighting the potential therapeutic applications of this protein. PMID:15708745

  14. Random Matrices in Non-confining Potentials

    NASA Astrophysics Data System (ADS)

    Allez, Romain; Dumaz, Laure

    2015-08-01

    We consider invariant matrix processes diffusing in non-confining cubic potentials of the form . We construct the trajectories of such processes for all time by restarting them whenever an explosion occurs, from a new (well chosen) initial condition, insuring continuity of the eigenvectors and of the non exploding eigenvalues. We characterize the dynamics of the spectrum in the limit of large dimension and analyze the stationary state of this evolution explicitly. We exhibit a sharp phase transition for the limiting spectral density at a critical value . If , then the potential presents a well near deep enough to confine all the particles inside, and the spectral density is supported on a compact interval. If however, the steady state is in fact dynamical with a macroscopic stationary flux of particles flowing across the system. We prove that this flux displays a second order phase transition at the critical value such that when where is an explicit constant. In the subcritical regime, the eigenvalues allocate according to a stationary density profile with full support in , flanked with heavy tails such that as . Our method applies to other non-confining potentials and we further investigate a family of quartic potentials, which were already studied in (Brezin et al. in Commun Math Phys 59:35-51, 1978) to count planar diagrams.

  15. A preliminary look at electric efficiency potential

    SciTech Connect

    Chandler, Jess

    2010-01-15

    A systematic review of more than 20 studies of electric efficiency potential suggests that, contrary to what might be desired of such objective analysis, the study author, sponsor, and intended audience may matter in the conclusions that are reached. This pattern warrants further study. (author)

  16. Spontaneous Biliteracy: Examining Latino Students' Untapped Potential

    ERIC Educational Resources Information Center

    de la Luz Reyes, Maria

    2012-01-01

    Cultural deficit theories have long been debunked, yet Spanish continues to be treated as an impediment to Latinos' school success. With over 5 million emerging bilinguals, of which approximately 75% are Spanish speakers, Latinos' biliteracy potential should be examined as a means to support their learning. This article focuses on the spontaneous…

  17. Emotion Potentiated Startle in Fragile X Syndrome

    ERIC Educational Resources Information Center

    Ballinger, Elizabeth C.; Cordeiro, Lisa; Chavez, Alyssa D.; Hagerman, Randi J.; Hessl, David

    2014-01-01

    Social avoidance and anxiety are prevalent in fragile X syndrome (FXS) and are potentially mediated by the amygdala, a brain region critical for social behavior. Unfortunately, functional brain resonance imaging investigation of the amygdala in FXS is limited by the difficulties experienced by intellectually impaired and anxious participants. We…

  18. Disappearing inflaton potential via heavy field dynamics

    NASA Astrophysics Data System (ADS)

    Kitajima, Naoya; Takahashi, Fuminobu

    2016-02-01

    We propose a possibility that the inflaton potential is significantly modified after inflation due to heavy field dynamics. During inflation such a heavy scalar field may be stabilized at a value deviated from the low-energy minimum. In extreme cases, the inflaton potential vanishes and the inflaton becomes almost massless at some time after inflation. Such transition of the inflaton potential has interesting implications for primordial density perturbations, reheating, creation of unwanted relics, dark radiation, and experimental search for light degrees of freedom. To be concrete, we consider a chaotic inflation in supergravity where the inflaton mass parameter is promoted to a modulus field, finding that the inflaton becomes stable after the transition and contributes to dark matter. Another example is a hilltop inflation (also called new inflation) by the MSSM Higgs field which acquires a large expectation value just after inflation, but it returns to the origin after the transition and finally rolls down to the electroweak vacuum. Interestingly, the smallness of the electroweak scale compared to the Planck scale is directly related to the flatness of the inflaton potential.

  19. Information entropy of conditionally exactly solvable potentials

    SciTech Connect

    Dutta, D.; Roy, P.

    2011-03-15

    We evaluate Shannon entropy for the position and momentum eigenstates of some conditionally exactly solvable potentials which are isospectral to harmonic oscillator and whose solutions are given in terms of exceptional orthogonal polynomials. The Bialynicki-Birula-Mycielski inequality has also been tested for a number of states.

  20. Improved Panel-Method/Potential-Flow Code

    NASA Technical Reports Server (NTRS)

    Ashby, Dale L.

    1991-01-01

    Panel code PMARC (Panel Method Ames Research Center) numerically simulates flow field around complex three-dimensional bodies, such as complete aircraft models. Based on potential-flow theory. Written in FORTRAN 77, with exception of namelist extension used for input. Structure facilitates addition of new features to code and tailoring of code to specific problems and computer hardware constraints.

  1. Some iterative schemes for transonic potential flows

    NASA Technical Reports Server (NTRS)

    Wong, Y. S.; Hafez, M. M.

    1985-01-01

    The minimal residual (MR) method for the numerical solution of transonic potential flows is closely related to the conjugate gradient method, which has found widespread use in the solution of large sparse, symmetric, and positive-definite linear equations. The primary advantage of the MR method is its applicability to both symmetric and nonsymmetric matrices.

  2. Computation of Transonic Flows Using Potential Methods

    NASA Technical Reports Server (NTRS)

    Hoist, Terry L.; Kwak, Dochan (Technical Monitor)

    1997-01-01

    The proposed paper will describe the state of the art associated with numerical solution of the full or exact velocity potential equation for solving transonic, external-aerodynamic flows. The presentation will begin with a review of the literature emphasizing research activities of the past decade. Next, the various forms of the full or exact velocity potential equation, the equation's corresponding mathematical characteristics, and the derivation assumptions will be presented and described in detail. Impact of the derivation assumptions on simulation accuracy, especially with respect to shock wave capture, will be presented and discussed relative to the more complete Euler or Navier-Stokes formulations. The technical presentation will continue with a description of recently developed full potential numerical approach characteristics. This description will include governing equation nondimensionalization, physical-to-computational-domain mapping procedures, a limited description of grid generation requirements, the spatial discretization scheme, numerical implementation of boundary conditions, and the iteration scheme. The next portion of the presentation will present and discuss numerical results for several two- and three-dimensional aerodynamic applications. Included in the results section will be a discussion and demonstration of a typical grid refinement analysis for determining spatial convergence of the numerical solution and level of solution accuracy. Computer timings for a variety of full potential applications will be compared and contrasted with similar results for the Euler equation formulation. Finally. the presentation will end with concluding remarks and recommendations for future work.

  3. Random Walk Method for Potential Problems

    NASA Technical Reports Server (NTRS)

    Krishnamurthy, T.; Raju, I. S.

    2002-01-01

    A local Random Walk Method (RWM) for potential problems governed by Lapalace's and Paragon's equations is developed for two- and three-dimensional problems. The RWM is implemented and demonstrated in a multiprocessor parallel environment on a Beowulf cluster of computers. A speed gain of 16 is achieved as the number of processors is increased from 1 to 23.

  4. Geothermal Energy Potential in Western United States

    ERIC Educational Resources Information Center

    Pryde, Philip R.

    1977-01-01

    Reviews types of geothermal energy sources in the western states, including hot brine systems and dry steam systems. Conversion to electrical energy is a major potential use of geothermal energy, although it creates environmental disruptions such as noise, corrosion, and scaling of equipment. (AV)

  5. The Power and Potential of Primary Sources

    ERIC Educational Resources Information Center

    Morgan, Denise N.; Rasinski, Timothy V.

    2012-01-01

    Using primary sources with students has untapped potential for expanding and deepening the reading experiences of elementary and middle grade students. Primary sources expands teachers' palette of reading materials, allows students to connect more closely to topics for learning, and deepens their understanding of the past. This article argues for…

  6. EVALUATION OF THE POTENTIAL CARCINOGENICITY OF CYCLOPHOSPHAMIDE

    EPA Science Inventory

    Cyclophosphamide is a probable human carcinogen, classified as weight-of-evidence Group B1 under the EPA Guidelines for Carcinogen Risk Assessment (U.S. EPA, 1986a).Evidence on potential carcinogenicity from animal studies is "Sufficient," and the evidence from human studies is "...

  7. The Aging Mind: Potential and Limits.

    ERIC Educational Resources Information Center

    Baltes, Paul B.

    1993-01-01

    Notes that research on aging mind has moved from simple growth versus decline view to conception of joint consideration of potential and limits. Sees this development illustrated by research on two categories of cognitive functioning: the cognitive mechanics (comparable to fluid intelligence) and cognitive pragmatics (comparable to crystallized…

  8. Potential of energy production from conserved forages

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Forages have a potential role in meeting the demand for energy. Perennial forages are attractive for various reasons. One, both the monetary and energy cost of planting is spread over many years. Two, we already have the equipment for harvesting, storing and transporting this source of biomass. Thre...

  9. Tumour vasculature--a potential therapeutic target.

    PubMed Central

    Baillie, C. T.; Winslet, M. C.; Bradley, N. J.

    1995-01-01

    The tumour vasculature is vital for the establishment, growth and metastasis of solid tumours. Its physiological properties limit the effectiveness of conventional anti-cancer strategies. Therapeutic approaches directed at the tumour vasculature are reviewed, suggesting the potential of anti-angiogenesis and the targeting of vascular proliferation antigens as cancer treatments. PMID:7543770

  10. Distance Learning: New Technology and New Potential.

    ERIC Educational Resources Information Center

    Bell, Julie Davis

    1991-01-01

    Some common questions that state legislators have about how distance learning can work in their states are explored. Distance learning, once considered strictly a rural education strategy, is now recognized to have the potential to provide solutions to some of the problems states face in delivering quality education to all students. A distance…

  11. The potential for chemical evolution on Titan

    NASA Technical Reports Server (NTRS)

    Beauchamp, P. M.; Lunine, J. I.; Welch, C.

    2002-01-01

    Sampling of organics to determine oxygen content, extent of acetylene polymerization, existence of chiral molecules and enantiomeric excesses, and searches for specific polymer products, would be of interest in assessing how organic chemistry evolves toward biochemistry. Such efforts would require fairly sophisticated chemical analyses from landed missions. This paper examines this chemistry and the potential instruments that could distinguish chemical evolution.

  12. Portable Micros: Potentials for Information Management.

    ERIC Educational Resources Information Center

    Davis, Charles H.

    1984-01-01

    Description of portable microcomputers discusses design features of Tandy TRS-80, Nippon Electric Company PC-8200, Epson HX-20, Texas Instruments TI CC 40, and Convergent Technologies' Workslate and provides several caveats and recommendations to those making purchasing decisions. Potential uses for portable microcomputers in education are also…

  13. [Potential radiation hazard in nuclear medicine].

    PubMed

    Guilabert, Nadine; Ricard, Marcel; Chamoulaud, Karen; Mazelier, Carole; Schlumberger, Martin

    2015-01-01

    Nuclear medicine uses unsealed radioisotopes. The potential radiation hazards depend on the amount of radioactivity administered and the type of radionucleide. Thus, radiation safety instructions will minimize radiation exposure and contamination as low as reasonably achievable. National nuclear safety authority requires rules, regulations and exposure limits for both patients and workers. Good practices and training staff contribute to optimize the radioprotection. PMID:25842441

  14. Developing Human Resources through Actualizing Human Potential

    ERIC Educational Resources Information Center

    Clarken, Rodney H.

    2012-01-01

    The key to human resource development is in actualizing individual and collective thinking, feeling and choosing potentials related to our minds, hearts and wills respectively. These capacities and faculties must be balanced and regulated according to the standards of truth, love and justice for individual, community and institutional development,…

  15. Yield potential of pigeon pea cultivars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Yield potential of twelve vegetable pigeon pea (Cajanus cajun) cultivars was evaluated at two locations in eastern Kenya during 2012 and 2013 cropping years. Pigeon pea pod numbers, seeds per pod, seed mass, grain yield and shelling percentage were quantified in three replicated plots, arranged in a...

  16. EVALUATION OF THE POTENTIAL CARCINOGENICITY OF DAUNOMYCIN

    EPA Science Inventory

    Daunomycin is a probable human carcinogen, classified as weight-of-evidence Group B2 under the EPA Guidelines for Carcinogen Risk Assessment (U.S. EPA, 1986a). vidence on potential carcinogenicity from animal studies is "Sufficient," and the evidence from human studies is "No Dat...

  17. FPP [Floating Potential Probe] Results, Final Report

    NASA Technical Reports Server (NTRS)

    Ferguson, Dale C.

    2007-01-01

    The Floating Potential Probe (FPP) operated on the International Space Station (ISS) from December 2000 to April 2001. During that time, it took many measurements of the ISS floating potential and the electron density and temperature. Those measurements were used as inputs to the Environments WorkBench (EWB) model of ISS potentials (originally developed by SAIC, but now sometimes called the Boeing model) that is used even today to predict charging levels for ISS. FPP is now completely defunct, having been removed and ejected from ISS. With the advent of the new Floating Potential Monitoring Unit (FPMU) on ISS, and the beginning of ISS operations with two large solar array panels instead of just one, a review of FPP measurements can offer comparisons with the new FPMU data and perhaps improve the accuracy of future ISS charging predictions. In particular, FPP measurements during times of low electron temperature and high electron density (the times of worst ISS charging) will be brought forward for comparison with the newly obtained FPMU data.

  18. Potential Nuclear Conflict: Attention Adult Educators.

    ERIC Educational Resources Information Center

    Gleazer, Edmund J.

    1983-01-01

    Teaching about potential nuclear conflict is increasing in schools, colleges, and universities. A group of faculty from many universities across the United States has formed United Campuses to Prevent Nuclear War (UCAM) to produce teaching materials and publish summaries of courses on nuclear war. One such course at Lafayette College…

  19. Spinal evoked potentials following transcranial magnetic stimulation.

    PubMed

    Nemoto, J; Sasaki, T; Kikuchi, Y; Konno, Y; Sakuma, J; Kodama, N

    2001-06-01

    Motor evoked potentials by magnetic stimulation is less invasive and causes no pain as opposed to high current electric stimulation. However, the distribution of the magnetic field generated by the round coil has not been fully studied. In this report, we mapped the extent of the magnetic induction flux density, and then the evoked potentials from the spinal cord were investigated by transcranial magnetic stimulation. We also examined the origin of the evoked potentials obtained by the magnetic stimulation. The following results were obtained. The magnetic induction flux density was at its maximum at the edge of the coil. The potentials consisted of a first negative wave and subsequent multiphasic waves. The first negative wave was similar to a response of the subcorticospinal tract in the lower brain stem, while the subsequent multiphasic waves were similar to those of the pyramidal tract. Although magnetic stimulation has certain advantages over electric stimulation, several problems remain to be solved for the monitoring of motor functions in the clinical settings. PMID:11764415

  20. Potential commercial applications of microbial surfactants.

    PubMed

    Banat, I M; Makkar, R S; Cameotra, S S

    2000-05-01

    Surfactants are surface-active compounds capable of reducing surface and interfacial tension at the interfaces between liquids, solids and gases, thereby allowing them to mix or disperse readily as emulsions in water or other liquids. The enormous market demand for surfactants is currently met by numerous synthetic, mainly petroleum-based, chemical surfactants. These compounds are usually toxic to the environment and non-biodegradable. They may bio-accumulate and their production, processes and by-products can be environmentally hazardous. Tightening environmental regulations and increasing awareness for the need to protect the ecosystem have effectively resulted in an increasing interest in biosurfactants as possible alternatives to chemical surfactants. Biosurfactants are amphiphilic compounds of microbial origin with considerable potential in commercial applications within various industries. They have advantages over their chemical counterparts in biodegradability and effectiveness at extreme temperature or pH and in having lower toxicity. Biosurfactants are beginning to acquire a status as potential performance-effective molecules in various fields. At present biosurfactants are mainly used in studies on enhanced oil recovery and hydrocarbon bioremediation. The solubilization and emulsification of toxic chemicals by biosurfactants have also been reported. Biosurfactants also have potential applications in agriculture, cosmetics, pharmaceuticals, detergents, personal care products, food processing, textile manufacturing, laundry supplies, metal treatment and processing, pulp and paper processing and paint industries. Their uses and potential commercial applications in these fields are reviewed. PMID:10855707

  1. Student Human Potential: Going beyond the Basics.

    ERIC Educational Resources Information Center

    White, Sylvia Ann

    The expansion of human potential and the accompanying increase in self-esteem and self-actualization is the key to emotional and physical health, social relations, learning problems, self-discipline, and future survival. Self-knowledge, obtained through such measures as keeping records of moods and through biomechanical devices, can enable…

  2. Air Pollution Potential from Electroplating Operations.

    ERIC Educational Resources Information Center

    Diamond, Philip

    Measurements were made of emission rates from electroplating operations considered to have maximum air pollution potential. Sampling was performed at McClellan and additional data from a previous survey at Hill Air Force Base was used. Values obtained were extremely low. Based on existing Federal standards, no collectors are specifically required…

  3. The National Potential of Home Equity Conversion.

    ERIC Educational Resources Information Center

    Jacobs, Bruce

    1986-01-01

    Examined the potential effects of converting home equity into spendable income using "reverse mortgages." Analysis revealed that reverse mortgage loans could have a substantial impact on the budgets of many elderly homeowners, with impressive percentage increases in income and decreases in poverty rates. (Author/ABB)

  4. Ammonium pelargonate as a potential organic herbicide

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Weed control is a serious concern for commercial vegetable producers because of the limited number of herbicides available for this group of minor crops and the potential for crop injury. Organic producers of vegetables have an even greater challenge since their weed control tools are limited to cu...

  5. EVALUATION OF THE POTENTIAL CARCINOGENICITY OF HYDRAZINE

    EPA Science Inventory

    Hydrazine is a probable human carcinogen, classified as weight-of-evidence Group B2 under the EPA Guidelines for Carcinogen Risk Assessment (U.S. EPA, 1986a). vidence on potential carcinogenicity from animal studies is "sufficient," and the evidence from human studies is "Inadequ...

  6. Measurement of redox potential in nanoecotoxicological investigations.

    PubMed

    Tantra, Ratna; Cackett, Alex; Peck, Roger; Gohil, Dipak; Snowden, Jacqueline

    2012-01-01

    Redox potential has been identified by the Organisation for Economic Co-operation and Development (OECD) as one of the parameters that should be investigated for the testing of manufactured nanomaterials. There is still some ambiguity concerning this parameter, i.e., as to what and how to measure, particularly when in a nanoecotoxicological context. In this study the redox potentials of six nanomaterials (either zinc oxide (ZnO) or cerium oxide (CeO(2))) dispersions were measured using an oxidation-reduction potential (ORP) electrode probe. The particles under testing differed in terms of their particle size and dispersion stability in deionised water and in various ecotox media. The ORP values of the various dispersions and how they fluctuate relative to each other are discussed. Results show that the ORP values are mainly governed by the type of liquid media employed, with little contributions from the nanoparticles. Seawater was shown to have reduced the ORP value, which was attributed to an increase in the concentration of reducing agents such as sulphites or the reduction of dissolved oxygen concentration. The lack of redox potential value contribution from the particles themselves is thought to be due to insufficient interaction of the particles at the Pt electrode of the ORP probe. PMID:22131988

  7. Marketing Potential of Advanced Breeding Clones

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The accumulation of reducing sugars during cold storage of potato tubers is a serious and costly problem for producers and processors. The degree to which cultivars accumulate reducing sugars during storage determines their processing and market potential. Cultivars or advanced breeding lines with...

  8. Positive lithiation potential on functionalized Graphene sheets

    NASA Astrophysics Data System (ADS)

    Chouhan, Rajiv Kumar; Raghani, Pushpa

    2015-03-01

    Designing lithium batteries with high capacities is major challenge in the field of energy storage. As an alternative to the conventional graphitic anode with a capacity of ~372 mAhg-1 , we look at the adsorption of lithium on 2D graphene oxide (GO) sheets. We have included van-der-waal's interaction in our calculation and compared with literature showing its importance in Li binding on Graphene sheets. In comparison to the negative lithiation potential in prestine graphene sheets, we were able to get positive lithiation potential by introducing functional groups such as epoxy(-O-) and hydroxyl(-OH) on graphene. Also the non-stoichiometic nature of GO provides better potential to increase the lithiation potential in compare to the defects induced graphene 2D sheet. Dramatic charge redistribution within the sheet due to presence of highly electronegative oxygen plays an important role in increasing the capacity. Financial support from Research Corporation's Cottrell College Science award and National Science Foundation's CAREER award (DMR-1255584). Computational facilities provided by HPC center of Idaho National Laboratory.

  9. Eag1 channels as potential cancer biomarkers.

    PubMed

    Rodríguez-Rasgado, Jesús Adrián; Acuña-Macías, Isabel; Camacho, Javier

    2012-01-01

    Cancer is a leading cause of death worldwide. New early tumor markers are needed to treat the disease at curable stages. In addition, new therapeutic targets are required to treat patients not responding to available treatments. Ion channels play major roles in health and disease, including cancer. Actually, several ion channels have been suggested as potential tumor markers and therapeutic targets for different types of malignancies. One of most studied ion channels in cancer is the voltage-gated potassium channel Eag1 (ether à go-go 1), which has a high potential to be used as a cancer biomarker. Eag1 is expressed in most human tumors, in contrast to its restricted distribution in healthy tissues. Several findings suggest Eag1 as a potential early marker for cervical, colon, and breast cancer. In addition, because Eag1 amplification/expression is associated with poor survival in leukemia, colon and ovarian cancer patients, it has also been proposed as a prognosis marker. Moreover, inhibition of either expression or activity of Eag1 leads to reduced proliferation of cancer cells, making Eag1 a potential anticancer target. Using Eag1 in cancer detection programs could help to reduce mortality from this disease. PMID:22778627

  10. Drought, Climate Change and Potential Agricultural Productivity

    NASA Astrophysics Data System (ADS)

    Sheffield, J.; Herrera-Estrada, J. E.; Caylor, K. K.; Wood, E. F.

    2011-12-01

    Drought is a major factor in agricultural productivity, especially in developing regions where the capacity for water resources management is limited and climate variability ensures that drought is recurrent and problematic. Recent events in East Africa are testament to this, where drought conditions that have slowly developed over multiple years have contributed to reduced productivity and ultimately food crises and famine. Prospects for the future are not promising given ongoing problems of dwindling water supplies from non-renewable sources and the potential for increased water scarcity and increased drought with climate change. This is set against the expected increase in population by over 2 billion people by 2050 and rise in food demand, coupled with changes in demographics that affect food choices and increases in non-food agriculture. In this talk we discuss the global variability of drought over the 20th century and recent years, and the projected changes over the 21st century, and how this translates into changes in potential agricultural productivity. Drought is quantified using land surface hydrological models driven by a hybrid reanalysis-observational meteorological forcing dataset. Drought is defined in terms of anomalies of hydroclimatic variables, in particular precipitation, evaporation and soil moisture, and we calculate changes in various drought characteristics. Potential agricultural productivity is derived from the balance of precipitation to crop water demand, where demand is based on potential evaporation and crop coefficients for a range of staple crops. Some regional examples are shown of historic variations in drought and potential productivity, and the estimated water deficit for various crops. The multitude of events over the past decade, including heat waves in Europe, fires in Russia, long-term drought in northern China, southeast Australia, the Western US and a series of droughts in the Amazon and Argentina, hint at the influence of

  11. Evaluation of groundwater potential using geospatial techniques

    NASA Astrophysics Data System (ADS)

    Hussein, Abdul-Aziz; Govindu, Vanum; Nigusse, Amare Gebre Medhin

    2016-06-01

    The issue of unsustainable groundwater utilization is becoming increasingly an evident problem and the key concern for many developing countries. One of the problems is the absence of updated spatial information on the quantity and distribution of groundwater resource. Like the other developing countries, groundwater evaluation in Ethiopia has been usually conducted using field survey which is not feasible in terms of time and resource. This study was conducted in Northern Ethiopia, Wollo Zone, in Gerardo River Catchment district to spatially delineate the groundwater potential areas using geospatial and MCDA tools. To do so, eight major biophysical and environmental factors like geomorphology, lithology, slope, rainfall, land use land cover (LULC), soil, lineament density and drainage density were considered. The sources of these data were satellite image, digital elevation model (DEM), existing thematic maps and metrological station data. Landsat image was used in ERDAS Imagine to drive the LULC of the area, while the geomorphology, soil, and lithology of the area were identified and classified through field survey and digitized from existing maps using the ArcGIS software. The slope, lineament and drainage density of the area were derived from DEM using spatial analysis tools. The rainfall surface map was generated using the thissen polygon interpolation. Finally, after all these thematic maps were organized, weighted value determination for each factor and its field value was computed using IDRSI software. At last, all the factors were integrated together and computed the model using the weighted overlay so that potential groundwater areas were mapped. The findings depicted that the most potential groundwater areas are found in the central and eastern parts of the study area, while the northern and western parts of the Gerado River Catchment have poor potential of groundwater availability. This is mainly due to the cumulative effect of steep topographic and

  12. Mapping ecosystem services potential in Lithuania

    NASA Astrophysics Data System (ADS)

    Depellegrin, Daniel; Misiune, Ieva; Pereira, Paulo

    2016-04-01

    Ecosystem services (ES) are understood as the benefits that humans get from ecosystems functions. They are divided in providing, regulating, supporting and cultural. The correct management of ES is fundamental to achieve sustainable development goals. A good assessment of ES potential can be obtained using GIS techniques, in order to have a spatial dimension of ES distribution. This will help to have a better territorial planning, improve ES capacity, and have more benefits. ES potential analysis can be carried out based on the ES matrix developed by Burkhard et al. (2009). This method is based on the attribution a rank from 0 to 5 (0= no capacity to 5=very high relevant capacity) to the land use classes of the corine land cover (CLC). This represents an important advantage since a determined land use can be related with a certain number of services. The objective of this work is to Map the ES potential in Lithuania. The results showed that Lithuania has a high potential for regulating services, followed by cultural and provisioning services. Urban areas provide a very small amount of services, contrary to forest, where the highest potential is observed. The most comon land covers in Lithuania are non-irrigated arable land, complex cultivation patterns, mixed and coniferous forest. Total and regulating and cultural ES had dispersed pattern showing that they are scattered in the territory. They are located mainly in forested and coastal areas. In relation to provisioning services they had a clustered distribution, and they were mainly observed in the central part of Lithuania. References Burkhard B, Kroll F, Müller F, Windhorst W. 2009. Landscapes' capacities to provide ecosystem services - a concept for land-cover based assessments. Landsc. Online. 15:1-22

  13. The Potential Geographic Range of Pyrenophora semeniperda.

    PubMed

    Yonow, Tania; Kriticos, Darren J; Medd, Richard W

    2004-08-01

    ABSTRACT There is no evidence that Pyrenophora semeniperda, the causal agent of leaf spotting in many annual and perennial grasses, currently occurs in Europe or Asia. However, there is potential phytosanitary concern that the importation of infected commodities could result in the introduction of this fungus into Eurasia, putting crops at risk and possibly resulting in economic losses. To assist in assessing the risk of geographic range extension of P. semeniperda, an analysis was undertaken to estimate the potential global distribution of this species, based on climatic suitability. Geographic distribution data for P. semeniperda in part of its current range were used to fit parameter values in a CLIMEX pest risk assessment model, and the remaining distribution data were used to validate the model. The CLIMEX model correctly predicts that virtually all locations where P. semeniperda has been found are climatically suitable. Only five locations worldwide where the fungus was recorded present are predicted as being unsuitable. These "outliers" may have been transient populations occurring during a favorable season and then dying out. Exploratory adjustments of the model to accommodate these records created unsatisfactory distortions in the projected climatic suitability surfaces, extending the suitable climatic zone beyond well-established traditional range boundaries. We are therefore confident that the model is credibly predicting the potential distribution of P. semeniperda worldwide. The CLIMEX model suggests that P. semeniperda could potentially extend its range throughout Europe and temperate regions of Asia, Africa, and South America. Our heavy reliance upon geographic data to build this CLIMEX model departs from most previous published examples in plant pathology, which have depended primarily upon experimentally derived physiological data to estimate model parameters. The use of geographic data to infer climate parameters is popular in CLIMEX models of

  14. An eddy closure for potential vorticity

    SciTech Connect

    Ringler, Todd D

    2009-01-01

    The Gent-McWilliams (GM) parameterization is extended to include a direct influence in the momentum equation. The extension is carried out in two stages; an analysis of the inviscid system is followed by an analysis of the viscous system. In the inviscid analysis the momentum equation is modified such that potential vorticity is conserved along particle trajectories following a transport velocity that includes the Bolus velocity in a manner exactly analogous to the continuity and tracer equations. In addition (and in contrast to traditional GM closures), the new formulation of the inviscid momentum equation results in a conservative exchange between potential and kinetic forms of energy. The inviscid form of the eddy closure conserves total energy to within an error proportional to the time derivative of the Bolus velocity. The hypothesis that the viscous term in the momentum equation should give rise to potential vorticity being diffused along isopycnals in a manner analogous to other tracers is examined in detail. While the form of the momentum closure that follows from a strict adherence to this hypothesis is not immediately interpretable within the constructs of traditional momentum closures, three approximations to this hypothesis results in a form of dissipation that is consistent with traditional Laplacian diffusion. The first two approximations are that relative vorticity, not potential vorticity, is diffused along isopyncals and that the flow is in approximate geostrophic balance. An additional approximation to the Jacobian term is required when the dissipation coefficient varies in space. More importantly, the critique of this hypothesis results in the conclusion that the viscosity parameter in the momentum equation should be identical to the tradition GM closure parameter {Kappa}. Overall, we deem the viscous form of the eddy closure for potential vorticity as a viable closure for use in ocean circulation models.

  15. Event related potentials in children of alcoholics.

    PubMed

    Naziel, B; Yavaş, G; Arikan, Z; Ozon, O; Aksoy Ozmenek, O; Irkeç, C

    2007-09-01

    Assessment of ERPs (Event Related Potentials) is a special area of interest in research on vulnerability to alcoholism in human subjects. ERP not only provide information about potential neurofunctional anomalies in healthy individuals, but also relate those neurofunctional characteristics to the cognitive process involved. The aim of the present study is to evaluate the effects of chronic alcoholism and alcoholism risk on children of alcoholic fathers by using ERP parameters. 24 children of alcoholic fathers (9 boys, 15 girls) with a mean age of 18 +/- 3 (range: 15-25) and 17 control subjects (children of non-alcoholic fathers with out a family history of alcoholism) were included to the study. The age range was from 15 to 25 (mean: 21 +/- 3). N200 potential latency recorded from the parietal electrode position was significantly prolonged (p = 0.032) and amplitudes of P200 potential also recorded from the parietal region was significantly low (p = 0.043) relative to controls. However, the rest of the event-related potential parameters including P300 latency and amplitudes recorded from FZ, CZ, PZ electrode positions did not differ significantly from the children of non-alcoholic fathers. The difference in our results from the previous studies may be due to various factors. Genetic, gender, environmental, educational and social factors may have an overall effect on ERP and we believe these factors may be the cause of the differences seen in our study when compared to the previous ones. We believe the gender differences in our group may have had effected the overall results. Consecutive studies with more subject participation are needed to confirm and settle this issue. PMID:17918508

  16. Statically screened ion potential and Bohm potential in a quantum plasma

    SciTech Connect

    Moldabekov, Zhandos; Schoof, Tim; Ludwig, Patrick; Bonitz, Michael; Ramazanov, Tlekkabul

    2015-10-15

    The effective potential Φ of a classical ion in a weakly correlated quantum plasma in thermodynamic equilibrium at finite temperature is well described by the random phase approximation screened Coulomb potential. Additionally, collision effects can be included via a relaxation time ansatz (Mermin dielectric function). These potentials are used to study the quality of various statically screened potentials that were recently proposed by Shukla and Eliasson (SE) [Phys. Rev. Lett. 108, 165007 (2012)], Akbari-Moghanjoughi (AM) [Phys. Plasmas 22, 022103 (2015)], and Stanton and Murillo (SM) [Phys. Rev. E 91, 033104 (2015)] starting from quantum hydrodynamic (QHD) theory. Our analysis reveals that the SE potential is qualitatively different from the full potential, whereas the SM potential (at any temperature) and the AM potential (at zero temperature) are significantly more accurate. This confirms the correctness of the recently derived [Michta et al., Contrib. Plasma Phys. 55, 437 (2015)] pre-factor 1/9 in front of the Bohm term of QHD for fermions.

  17. MAGNETOMETRY, SELF-POTENTIAL, AND SEISMIC - ADDITIONAL GEOPHYSICAL METHODS HAVING POTENTIALLY SIGNIFICANT FUTURE UTILIZATION IN AGRICULTURE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Geophysical methods can provide important information in agricultural settings, and the use of these techniques are becoming more and more widespread. Magnetrometry, self-potential, and seismic are three geophysical methods, all of which have the potential for substantial future use in agriculture, ...

  18. Relationship between potential platelet activation and LCS

    NASA Astrophysics Data System (ADS)

    Shadden, Shawn

    2010-11-01

    In the study of blood flow, emphasis is often directed at understanding shear stress at the vessel wall due to its potentially disruptive influence on the endothelium. However, it is also known that shear stress has a potent effect on platelet activation. Platelet activation is a precursor for blood clotting, which in turn is the cause of most forms of death. Since most platelets are contained in the flow domain, it is important to consider stresses acting on the platelet as they are convected. Locations of high stress can correspond to boundaries between different dynamic regions and locations of hyperbolic points in the Eulerian sense. In the computation of LCS, strain in typically considered in the Lagrangian sense. In this talk we discuss the relationship between locations of potential platelet activation due to increased stress and locations of LCS marking increase Lagrangian deformation.

  19. Mechanical surface waves accompany action potential propagation.

    PubMed

    El Hady, Ahmed; Machta, Benjamin B

    2015-01-01

    Many diverse studies have shown that a mechanical displacement of the axonal membrane accompanies the electrical pulse defining the action potential (AP). We present a model for these mechanical displacements as arising from the driving of surface wave modes in which potential energy is stored in elastic properties of the neuronal membrane and cytoskeleton while kinetic energy is carried by the axoplasmic fluid. In our model, these surface waves are driven by the travelling wave of electrical depolarization characterizing the AP, altering compressive electrostatic forces across the membrane. This driving leads to co-propagating mechanical displacements, which we term Action Waves (AWs). Our model allows us to estimate the shape of the AW that accompanies any travelling wave of voltage, making predictions that are in agreement with results from several experimental systems. Our model can serve as a framework for understanding the physical origins and possible functional roles of these AWs. PMID:25819404

  20. Venom-based biotoxins as potential analgesics.

    PubMed

    Gazerani, Parisa; Cairns, Brian Edwin

    2014-11-01

    Chronic pain is a common debilitating condition with negative social and economic consequences. Management of chronic pain is challenging and the currently available medications do not yet yield satisfactory outcomes for many patients. Venom-derived biotoxins from various venomous species consist of several substances with different structures and compositions that include peptides. A unique characteristic of some venom-based biotoxins is the ability to block essential components of the pain signaling system, notably ion channels. This property is leading to the evaluation of the potential of biotoxins as analgesics to manage chronic pain. In addition to their therapeutic potential, biotoxins have also been essential tools to probe mechanisms underlying pain signaling, channelopathies and receptor expression. This review discusses venom-derived peptidergic biotoxins that are in preclinical stages or already in clinical trials. Some promising results from preliminary in vitro studies, ongoing challenges and unmet needs will also be discussed. PMID:25234848

  1. Neopterin as a potential cytoprotective brain molecule.

    PubMed

    Ghisoni, Karina; Martins, Roberta de Paula; Barbeito, Luis; Latini, Alexandra

    2015-12-01

    Neopterin, a byproduct of the tetrahydrobiopterin de novo pathway, is found in increased levels in cerebrospinal fluid and plasma and significantly increases upon damage, infection or during immune system activation. The production of this compound seems almost restricted to the monocyte/macrophage linage cells, in response to interferon-γ stimulation. However, it is unclear whether and which nervous cells are able to synthesize neopterin, respond to any stressor applied extracellularly, or even the role of the compound in the central nervous system. Here we propose a potential cytoprotective role of neopterin in the brain, and show evidence that cultured rat astrocytes are responsive to the molecule; the pterin elicited increased hemeoxygenase-1 cellular content and decreased oxidative stress induced by mitochondrial dysfunction. Further studies are needed to clarify neopterin's cytoprotective effects in the central nervous system, and its potential role in different neuroinflammatory diseases. PMID:26476490

  2. Systemic targeted radionuclide therapy: Potential new areas

    SciTech Connect

    Wong, Jeffrey Y.C. . E-mail: jwong@coh.org

    2006-10-01

    Radiation oncology is entering an exciting new era with therapies being delivered in a targeted fashion through an increasing number of novel approaches. External beam radiotherapy now integrates functional and anatomic tumor imaging to guide delivery of conformal radiation to the tumor target. Systemic targeted radionuclide therapy (STaRT) adds an important new dimension by making available to Radiation oncologist biologically targeted radiation therapy. Impressive clinical results with antibody-targeted radiotherapy, leading to the Food and Drug Administration's approval of two anti-CD20 radiolabeled antibodies, highlight the potential of STaRT. Optimization strategies will further improve the efficacy of STaRT by improving delivery systems, modifying the tumor microenvironment to increase targeted dose, and maximizing dose effect. Ultimately, the greatest potential for STaRT will not be as monotherapy, but as therapy integrated into established multimodality regimens and used as adjuvant or consolidative therapy in patients with minimal or micrometastatic disease.

  3. Potential seen on Australia's Bonaparte exploration acreage

    SciTech Connect

    West, B.; Miyazaki, S. )

    1994-09-12

    Two of the offshore areas recently released for exploration bids by the Australian government are NT94-1 and NT94-2 covering 23,000 sq km in the oil producing Bonaparte basin off northwestern Australia 300 km northwest of Darwin. Three wells have been drilled in the two areas, including Evans Shoal-1 which made a gas discovery currently considered to be non-commercial. The results of a study by the Australian Bureau of Resource Sciences (BRS) have been synthesized into the Evans Shoal Area Bulletin and Data Base. BRS interprets the available geochemical and maturation data to indicate that potential source rocks are present in the Jurassic Plover formation and Flamingo group and the Cretaceous Bathurst Island group. The paper describes the area geology, play types, and gas and oil potential.

  4. Cellular membrane potentials induced by alternating fields

    PubMed Central

    Grosse, Constantino; Schwan, Herman P.

    1992-01-01

    Membrane potentials induced by external alternating fields are usually derived assuming that the membrane is insulating, that the cell has no surface conductance, and that the potentials are everywhere solutions of the Laplace equation. This traditional approach is reexamined taking into account membrane conductance, surface admittance, and space charge effects. We find that whenever the conductivity of the medium outside the cell is low, large corrections are needed. Thus, in most of the cases where cells are manipulated by external fields (pore formation, cell fusion, cell rotation, dielectrophoresis) the field applied to the cell membrane is significantly reduced, sometimes practically abolished. This could have a strong bearing on present theories of pore formation, and of the influence of weak electric fields on membranes. PMID:19431866

  5. Theoretical determinations of ionization potentials of dopamine

    NASA Astrophysics Data System (ADS)

    Lu, J. F.; Yu, Z. Y.

    2013-04-01

    Adiabatic and vertical ionization potentials (IPs) of nine conformers of dopamine in the gas phase are determined using density functional theory (DFT) B3LYP, B3P86, B3PW91 methods and high level ab initio HF method with 6-311++G** basis set, respectively. And the nine stable cationic states have been found in the ionization process of dopamine. Vertical ionization potentials of nine conformers of dopamine are calculated using the older outer-valence Green's function (OVGF) calculations at 6-311++G** basis set. Vibrational frequencies and infrared spectrum intensities of G1b and G1b+ at B3LYP/6-311++G** level are discussed.

  6. Strained Hydrocarbons as Potential Hypergolic Fuels

    NASA Technical Reports Server (NTRS)

    2005-01-01

    A storable combination of high-energy hypergolic fuel and oxidizer is advantageous to the future of reusable launch vehicles (RLVs). The combination will allow an increase in energy per unit volume of fuel and eliminate the need for an external ignition system. Strained systems have been studied as potential high-density fuels. Adding hypergolic functional groups, such as amino groups, to these hydrocarbons will potentially allow auto ignition of strained systems with hydrogen peroxide. Several straight chain amines and their strained counterparts containing an equivalent number of carbon atoms have been purchased and synthesized. These amines provide initial studies to determine the effects of fuel vapor pressure, strain energy, fuel miscibility, and amine substitution upon fuel ignition time and hypergolicity with hydrogen peroxide as an oxidizer.

  7. Ultrasoft fermionic excitation at finite chemical potential

    NASA Astrophysics Data System (ADS)

    Blaizot, Jean-Paul; Satow, Daisuke

    2014-05-01

    It has been suggested previously that an ultrasoft fermionic excitation develops, albeit with a small spectral weight, in a system of massless fermions and scalar bosons with Yukawa interaction at high temperature T. In this paper we study how this excitation is modified at finite chemical potential μ. We relate the existence of the ultrasoft mode to symmetries, in particular charge conjugation, and a supersymmetry of the free system which is spontaneously broken by finite temperature and finite density effects, as argued earlier by Lebedev and Smilga. A nonvanishing chemical potential breaks both symmetries explicitly and maximally at zero temperature where the mode ceases to exist. A detailed calculation indicates that the ultrasoft excitation persists as long as T≥0.71μ.

  8. Computed potential energy surfaces for chemical reactions

    NASA Technical Reports Server (NTRS)

    Walch, Stephen P.; Levin, Eugene

    1993-01-01

    A new global potential energy surface (PES) is being generated for O(P-3) + H2 yields OH + H. This surface is being fit using the rotated Morse oscillator method, which was used to fit the previous POL-CI surface. The new surface is expected to be more accurate and also includes a much more complete sampling of bent geometries. A new study has been undertaken of the reaction N + O2 yields NO + O. The new studies have focused on the region of the surface near a possible minimum corresponding to the peroxy form of NOO. A large portion of the PES for this second reaction has been mapped out. Since state to state cross sections for the reaction are important in the chemistry of high temperature air, these studies will probably be extended to permit generation of a new global potential for reaction.

  9. Computed potential energy surfaces for chemical reactions

    NASA Technical Reports Server (NTRS)

    Walch, Stephen P.

    1994-01-01

    Quantum mechanical methods have been used to compute potential energy surfaces for chemical reactions. The reactions studied were among those believed to be important to the NASP and HSR programs and included the recombination of two H atoms with several different third bodies; the reactions in the thermal Zeldovich mechanism; the reactions of H atom with O2, N2, and NO; reactions involved in the thermal De-NO(x) process; and the reaction of CH(squared Pi) with N2 (leading to 'prompt NO'). These potential energy surfaces have been used to compute reaction rate constants and rates of unimolecular decomposition. An additional application was the calculation of transport properties of gases using a semiclassical approximation (and in the case of interactions involving hydrogen inclusion of quantum mechanical effects).

  10. Computed potential energy surfaces for chemical reactions

    NASA Technical Reports Server (NTRS)

    Walch, Stephen P.

    1990-01-01

    The objective was to obtain accurate potential energy surfaces (PES's) for a number of reactions which are important in the H/N/O combustion process. The interest in this is centered around the design of the SCRAM jet engine for the National Aerospace Plane (NASP), which was envisioned as an air-breathing hydrogen-burning vehicle capable of reaching velocities as large as Mach 25. Preliminary studies indicated that the supersonic flow in the combustor region of the scram jet engine required accurate reaction rate data for reactions in the H/N/O system, some of which was not readily available from experiment. The most important class of combustion reactions from the standpoint of the NASP project are radical recombinaton reactions, since these reactions result in most of the heat release in the combustion process. Theoretical characterizations of the potential energy surfaces for these reactions are presented and discussed.

  11. Potential Modulation on Total Internal Reflection Ellipsometry.

    PubMed

    Liu, Wei; Niu, Yu; Viana, A S; Correia, Jorge P; Jin, Gang

    2016-03-15

    Electrochemical-total internal reflection ellipsometry (EC-TIRE) has been proposed as a technique to observe the redox reactions on the electrode surface due to its high phase sensitivity to the electrolyte/electrode interface. In this paper, we mainly focus on the influence of the potential modulation on the TIRE response. The analysis suggests that both dielectric constant variation of gold and the electric double layer transformation would modulate the reflection polarization of the surface. For a nonfaradaic process, the signal of TIRE would be proportional to the potential modulation. To testify the analysis, linear sweep voltammetry and open circuit measurement have been performed. The results strongly support the system analysis. PMID:26889871

  12. Morse Potential in the Momentum Representation

    NASA Astrophysics Data System (ADS)

    Sun, Guo-Hua; Dong, Shi-Hai

    2012-12-01

    The momentum representation of the Morse potential is presented analytically by hypergeometric function. The properties with respect to the momentum p and potential parameter β are studied. Note that |Ψ(p)| is a nodeless function and the mutual orthogonality of functions is ensured by the phase functions arg[Ψ(p)]. It is interesting to see that the |Ψ(p)| is symmetric with respect to the axis p = 0 and the number of wave crest of |Ψ(p)| is equal to n + 1. We also study the variation of |Ψ(p)| with respect to β. The amplitude of |Ψ(p)| first increases with the quantum number n and then deceases. Finally, we notice that the discontinuity in phase occurs at some points of the momentum p and the position and momentum probability densities are symmetric with respect to their arguments.

  13. Homogenization of Periodic Systems with Large Potentials

    NASA Astrophysics Data System (ADS)

    Allaire, Grégoire; Capdeboscq, Yves; Piatnitski, Andrey; Siess, Vincent; Vanninathan, M.

    2004-11-01

    We consider the homogenization of a system of second-order equations with a large potential in a periodic medium. Denoting by ɛ the period, the potential is scaled as ɛ-2. Under a generic assumption on the spectral properties of the associated cell problem, we prove that the solution can be approximately factorized as the product of a fast oscillating cell eigenfunction and of a slowly varying solution of a scalar second-order equation. This result applies to various types of equations such as parabolic, hyperbolic or eigenvalue problems, as well as fourth-order plate equation. We also prove that, for well-prepared initial data concentrating at the bottom of a Bloch band, the resulting homogenized tensor depends on the chosen Bloch band. Our method is based on a combination of classical homogenization techniques (two-scale convergence and suitable oscillating test functions) and of Bloch waves decomposition.

  14. Theoretical studies of potential energy surfaces.

    SciTech Connect

    Harding, L. B.

    2006-01-01

    The goal of this program is to calculate accurate potential energy surfaces for both reactive and nonreactive systems. To do this the electronic Schroedinger equation must be solved. Our approach starts with multiconfiguration self-consistent field (MCSCF) reference wave functions. These reference wavefunctions are designed to be sufficiently flexible to accurately describe changes in electronic structure over a broad range of geometries. Dynamical electron correlation effects are included via multireference, singles and doubles configuration interaction (MRCI) calculations. With this approach, we are able to provide chemically useful predictions of the energetics for many systems. A second aspect of this program is the development of techniques to fit multi-dimensional potential surfaces to convenient, global, analytic functions that can then be used in dynamics calculations.

  15. [Online-gambling - new hazard potential?].

    PubMed

    Yazdi, Kurosch; Yazdi, Karin

    2014-12-01

    Since the new American psychiatric classification, DSM V, was released, bringing together substance-related disorders and gambling disorder into one chapter, the addictive potential of gambling and sports wagering is beyond all question. Even the neurobiological processes of the brain show similarities in all addictive disorders. Gambling is more and more shifted into the cyberspace owing to the global expansion of the internet. The addictive potential of online-gambling seems to be higher than offline, though, which is also reflected by the patient population of the outpatient clinic for gambling addiction in Linz. This fact poses a challenge for the persons affected, therapists, gambling providers, legislator the society as a whole. PMID:25377378

  16. Potential flow about elongated bodies of revolution

    NASA Technical Reports Server (NTRS)

    Kaplan, Carl

    1936-01-01

    This report presents a method of solving the problem of axial and transverse potential flows around arbitrary elongated bodies of revolution. The solutions of Laplace's equation for the velocity potentials of the axial and transverse flows, the system of coordinates being an elliptic one in a meridian plane, are given. The theory is applied to a body of revolution obtained from a symmetrical Joukowsky profile, a shape resembling an airship hull. The pressure distribution and the transverse-force distribution are calculated and serve as examples of the procedure to be followed in the case of an actual airship. A section on the determination of inertia coefficients is also included in which the validity of some earlier work is questioned.

  17. Therapeutic potential of curcumin in gastrointestinal diseases.

    PubMed

    Rajasekaran, Sigrid A

    2011-02-15

    Curcumin, also known as diferuloylmethane, is derived from the plant Curcuma longa and is the active ingredient of the spice turmeric. The therapeutic activities of curcumin for a wide variety of diseases such as diabetes, allergies, arthritis and other chronic and inflammatory diseases have been known for a long time. More recently, curcumin's therapeutic potential for preventing and treating various cancers is being recognized. As curcumin's therapeutic promise is being explored more systematically in various diseases, it has become clear that, due to its increased bioavailability in the gastrointestinal tract, curcumin may be particularly suited to be developed to treat gastrointestinal diseases. This review summarizes some of the current literature of curcumin's anti-inflammatory, anti-oxidant and anti-cancer potential in inflammatory bowel diseases, hepatic fibrosis and gastrointestinal cancers. PMID:21607160

  18. Potential Vorticity Analysis of Tropical Cyclone Intensification.

    NASA Astrophysics Data System (ADS)

    Molinari, John; Skubis, Steven; Vollaro, David; Alsheimer, Frank; Willoughby, Hugh E.

    1998-08-01

    The interaction of marginal Tropical Storm Danny (1985) with an upper-tropospheric positive potential vorticity anomaly was examined. The intensification mechanism proposed earlier for mature Hurricane Elena appears to be valid for Danny as well, despite significant differences in the synoptic-scale environment and in the stage of the tropical cyclone prior to the interaction. Both storms experienced rapid pressure falls as a relatively small-scale positive upper potential vorticity anomaly began to superpose with the low-level tropical cyclone center.The interaction is described in terms of a complex interplay between vertical wind shear, diabatic heating, and mutual advection among vortices at and below the level of the outflow anticyclone. Despite this complexity, the superposition principle appears to be conceptually useful to describe the intensification of tropical cyclones during such interactions.

  19. Blocking of potentiation of latent inhibition.

    PubMed

    Hall, Geoffrey; Rodriguez, Gabriel

    2011-01-01

    We present a theory of latent inhibition based on the Pearce-Hall (Pearce & Hall, 1980) model for classical conditioning. Its central features are (1) that the associability of a stimulus declines as it comes to predict its consequences and (2) that nonreinforced exposure to a stimulus engages an associative learning process that makes the stimulus an accurate predictor of its consequences (in this case, the occurrence of no event). A formalization of this theory is shown to accommodate the finding that preexposure in compound with another cue can potentiate latent inhibition to the target cue. It further predicts that preexposure to the added cue will eliminate the potentiation effect. An experiment using rats and the flavor-aversion procedure confirmed this prediction. PMID:20822295

  20. Potential Targets for Colorectal Cancer Prevention

    PubMed Central

    Temraz, Sally; Mukherji, Deborah; Shamseddine, Ali

    2013-01-01

    The step-wise development of colorectal neoplasia from adenoma to carcinoma suggests that specific interventions could delay or prevent the development of invasive cancer. Several key factors involved in colorectal cancer pathogenesis have already been identified including cyclooxygenase 2 (COX-2), nuclear factor kappa B (NF-κB), survivin and insulin-like growth factor-I (IGF-I). Clinical trials of COX-2 inhibitors have provided the “proof of principle” that inhibition of this enzyme can prevent the formation of colonic adenomas and potentially carcinomas, however concerns regarding the potential toxicity of these drugs have limited their use as a chemopreventative strategy. Curcumin, resveratrol and quercetin are chemopreventive agents that are able to suppress multiple signaling pathways involved in carcinogenesis and hence are attractive candidates for further research. PMID:23975167