WorldWideScience

Sample records for plausible primitive earth

  1. Synthesis of putrescine under possible primitive earth conditions

    Science.gov (United States)

    Wong, Carlos; Santiago, J. Carlos; Rodriguez-Paez, Lorena; Ibánez, Miguel; Baeza, Isabel; Oró, J.

    1991-05-01

    The synthesis of putrescine was accomplished by decarboxylation of L-orithine when this amino acid was heated in aqueous solution and in the absence of oxygen. Chromatographic, radioisotopic, and enzymatic techniques were used to demonstrate that one mole of non-radioactive putrescine and one mole of14CO2 was formed during the heating of L-(1-14C)-ornithine. This work indicates that the synthesis of putrescine can occur starting with ornithine and in conditions that are presumed could have existed on the primitive Earth. The possible significance of these results in the prebiotic molecular evolution is briefly discussed.

  2. Synthesis of oligoguanylates on oligocytidylate templates. [on primitive earth

    Science.gov (United States)

    Fakhrai, H.; Van Roode, J. H. G.; Orgel, L. E.

    1981-01-01

    The influence of template length in the self-condensation of guanosine 5'-phosphorimidazole in the presence of oligocytidylate templates is investigated. Reactions were carried out with cyclic cytidine 2',3'-phosphate, oligo- or polyC, and radioactively labeled guanosine 5'-phosphorimidazolide in the presence of Zn(+2) or Pb(+2) catalyst; product yields were determined by paper chromatography, thin-layer chromatography, and high-performance liquid chromatography. In the absence of a catalytic metal or in the presence of Pb(+2), a significant template effect is observed starting with the cytidine dimer and increasing in yield up to the hexamer template. Oligomers longer than the template are observed, and are predominantly 2'-5' linked in the presence of Pb(+2) and of mixed linkages in the uncatalyzed reaction. With the zinc ion as the catalyst, the template effect is first observed with the pentamer and is maximal with the heptamer. Products are predominantly 3'-5', and only a small proportion of them are longer than the template. The importance of the demonstrated formation of molecules with up to 10 guanosine units from oligocytidines as short as the dimer on the primitive earth is noted.

  3. Delivery of extraterrestrial amino acids to the primitive Earth. Exposure experiments in Earth orbit.

    Science.gov (United States)

    Barbier, B; Bertrand, M; Boillot, F; Chabin, A; Chaput, D; Henin, O; Brack, A

    1998-06-01

    A large collection of micrometeorites has been recently extracted from Antarctic old blue ice. In the 50 to 100 micrometers size range, the carbonaceous micrometeorites represent 80% of the samples and contain 2% of carbon. They might have brought more carbon to the surface of the primitive Earth than that involved in the present surficial biomass. Amino acids such as "-amino isobutyric acid have been identified in these Antarctic micrometeorites. Enantiomeric excesses of L-amino acids have been detected in the Murchison meteorite. A large fraction of homochiral amino acids might have been delivered to the primitive Earth via meteorites and micrometeorites. Space technology in Earth orbit offers a unique opportunity to study the behaviour of amino acids required for the development of primitive life when they are exposed to space conditions, either free or associated with tiny mineral grains mimicking the micrometeorites. Our objectives are to demonstrate that porous mineral material protects amino acids in space from photolysis and racemization (the conversion of L-amino acids into a mixture of L- and D-molecules) and to test whether photosensitive amino acids derivatives can polymerize in mineral grains under space conditions. The results obtained in BIOPAN-1 and BIOPAN-2 exposure experiments on board unmanned satellite FOTON are presented.

  4. A plausible simultaneous synthesis of amino acids and simple peptides on the primordial Earth.

    Science.gov (United States)

    Parker, Eric T; Zhou, Manshui; Burton, Aaron S; Glavin, Daniel P; Dworkin, Jason P; Krishnamurthy, Ramanarayanan; Fernández, Facundo M; Bada, Jeffrey L

    2014-07-28

    Following his seminal work in 1953, Stanley Miller conducted an experiment in 1958 to study the polymerization of amino acids under simulated early Earth conditions. In the experiment, Miller sparked a gas mixture of CH4, NH3, and H2O, while intermittently adding the plausible prebiotic condensing reagent cyanamide. For unknown reasons, an analysis of the samples was not reported. We analyzed the archived samples for amino acids, dipeptides, and diketopiperazines by liquid chromatography, ion mobility spectrometry, and mass spectrometry. A dozen amino acids, 10 glycine-containing dipeptides, and 3 glycine-containing diketopiperazines were detected. Miller's experiment was repeated and similar polymerization products were observed. Aqueous heating experiments indicate that Strecker synthesis intermediates play a key role in facilitating polymerization. These results highlight the potential importance of condensing reagents in generating diversity within the prebiotic chemical inventory.

  5. Comets and the formation of biochemical compounds on the primitive Earth--a review.

    Science.gov (United States)

    Oró, J; Mills, T; Lazcano, A

    1992-01-01

    Thirty years ago it was suggested that comets impacting on the primitive Earth may have represented a significant source of terrestrial volatiles, including some important precursors for prebiotic synthesis (Oró, 1961, Nature 190: 389). This possibility is strongly supported not only by models of the collisional history of the early Earth, but also by astronomical evidence that suggests that frequent collisions of comet-like bodies from the circumstellar disk around the star beta Pictoris are taking place. Although a significant fraction of the complex organic compounds that appear to be present in cometary nuclei were probably destroyed during impact, it is argued that cometary collisions with the primitive Earth represented an important source of both free-energy and volatiles, and may have created transient, gaseous environments in which prebiotic synthesis may have taken place.

  6. Comets and the formation of biochemical compounds on the primitive earth - A review

    Science.gov (United States)

    Oro, J.; Mills, T.; Lazcano, A.

    1992-01-01

    Thirty years ago it was suggested that comets impacting on the primitive earth may have represented a significant source of terrestrial volatiles, including some important precursors for prebiotic synthesis (Oro, 1961). This possibility is strongly supported not only by models of the collisional history of the early earth, but also by astronomical evidence that suggests that frequent collisions of cometlike bodies from the circumstellar disk around the star Beta Pictoris are taking place. Although a significant fraction of the complex organic compounds that appear to be present in cometary nuclei were probably destroyed during impact, it is argued that cometary collisions with the primitive earth represented an important source of both free-energy and volatiles, and may have created transient, gaseous environments in which prebiotic synthesis may have taken place.

  7. XUV complex refractive indices of aerosols in the atmospheres of Titan and the primitive Earth

    Science.gov (United States)

    Gavilan, Lisseth; Neumann, Maciej; Bulkin, Pavel; Popescu, Horia; Steffan, Martin; Esser, Norbert; Carrasco, Nathalie

    2016-10-01

    The complex refractive indices of tholins, simulating aerosols in the atmosphere of Titan and the primitive earth, have been measured over a wide spectral range, including the soft X-ray, vacuum-ultraviolet (VUV), and UV-Visible. The soft X-ray and VUV spectral ranges are in particular relevant to radiative transfer models of solar irradiation of primitive atmospheres (Lammer et al. 2008) and may elucidate the (anti-)greenhouse potential of photochemical aerosols.Thin films were grown using the PAMPRE capacitively coupled plasma setup (Szopa et al. 2006; Carrasco et al. 2009). Gas mixtures consisting of CH4/N2 with 5:95 ratios were used to simulate Titan's atmospheric composition. For the primitive Earth, gas mixtures of N2/CO2/H2 and N2/CO2/CH4 were used as described in Fleury et al. (2014).State-of-the-art laboratory techniques were used to determine the refractive indices of such tholin films. These include VUV ellipsometry (performed in collaboration with the Metrology Light Source in Berlin) and synchrotron X-ray spectroscopy (performed at the SEXTANTS beamline of the SOLEIL synchrotron). While VUV spectroscopy reveals new electronic transitions due to plasmon resonances in tholins, X-ray spectra reveal the C and O absorption edges of these solids. The refractive indices are compared to results from Khare et al. (1984). Implications on the optical properties of these aerosol analogs on the radiative modeling of primitive atmospheres will be discussed.

  8. Looking for the most ``primitive'' organism(s) on Earth today: the state of the art

    Science.gov (United States)

    Forterre, Patrick

    1995-02-01

    Molecular phylogenetic studies have revealed a tripartite division of the living world into two procaryotic groups, Bacteria and Archaea, and one eucaryotic group, Eucarya. Which group is the most "primitive"? Which groups are sister? The answer to these questions would help to delineate the characters of the last common ancestor to all living beings, as a first step to reconstruct the earliest periods of biological evolution on Earth. The current "Procaryotic dogma" claims that procaryotes are primitive. Since the ancestor of Archaea was most probably a hyperthermophile, and since bacteria too might have originated from hyperthermophiles, the procaryotic dogma has been recently connected to the hot origin of life hypothesis. However, the notion that present-day hyperthermophiles are primitive has been challenged by recent findings, in these unique microorganisms, of very elaborate adaptative devices for life at high temperature. Accordingly, I discuss here alternative hypotheses that challenge the procaryotic dogma, such as the idea of a universal ancestor with molecular features in between those of eucaryotes and procaryotes, or the origin of procaryotes via thermophilic adaptation. Clearly, major evolutionary questions about early cellular evolution on Earth remain to be settled before we can speculate with confidence about which kinds of life might have appeared on other planets.

  9. Looking for the most "primitive" organism(s) on Earth today: the state of the art.

    Science.gov (United States)

    Forterre, P

    1995-01-01

    Molecular phylogenetic studies have revealed a tripartite division of the living world into two procaryotic groups, Bacteria and Archaea, and one eucaryotic group, Eucarya. Which group is the most "primitive"? Which groups are sister? The answer to these questions would help to delineate the characters of the last common ancestor to all living beings, as a first step to reconstruct the earliest periods of biological evolution on Earth. The current "Procaryotic dogma" claims that procaryotes are primitive. Since the ancestor of Archaea was most probably a hyperthermophile, and since bacteria too might have originated from hyperthermophiles, the procaryotic dogma has been recently connected to the hot origin of life hypothesis. However, the notion that present-day hyperthermophiles are primitive has been challenged by recent findings, in these unique microorganisms, of very elaborate adaptative devices for life at high temperature. Accordingly, I discuss here alternative hypotheses that challenge the procaryotic dogma, such as the idea of a universal ancestor with molecular features in between those of eucaryotes and procaryotes, or the origin of procaryotes via thermophilic adaptation. Clearly, major evolutionary questions about early cellular evolution on Earth remain to be settled before we can speculate with confidence about which kinds of life might have appeared on other planets.

  10. The atmosphere of the primitive earth and the prebiotic synthesis of organic compounds

    Science.gov (United States)

    Miller, S. L.; Schlesinger, G.

    1983-01-01

    The prebiotic synthesis of organic compounds is investigated using a spark discharge on various simulated prebiotic atmospheres at 25 C. It is found that glycine is almost the only amino acid produced from the model atmospheres containing CO and CO2. These results show that the maximum yield is about the same for the three carbon sources (CO, CO2, and CH4) at high H2/carbon ratios, but that CH4 is superior at low H2/carbon ratios. CH4 is found to yield a much greater variety of amino acids than either CO or CO2. If it is assumed that amino acids more complex than glycine were required for the origin of life, then these findings indicate the need for CH4 in the primitive atmosphere. The yields of cyanide and formaldehyde are shown to parallel the amino acid results, with yields of HCN and H2CO as high as 13 percent based on carbon. Ammonia is also found to be produced from N2 in experiments with no added NH3 in yields as high as 4.9 percent. These results indicate that large amounts of NH3 would have been synthesized on the primitive earth by electric discharges.

  11. Origin of organic compounds on the primitive earth and in meteorites

    Science.gov (United States)

    Miller, S. L.; Urey, H. C.; Oro, J.

    1976-01-01

    The paper examines the role and relative contributions of different forms of energy to the synthesis of amino acids and other organic compounds on the primitive earth and in the solar nebula. Attention is directed mainly to the activation steps and formation of reactive intermediate compounds. Electric discharges appear to be not only the most efficient energy for amino acid synthesis but also yield a mixture of amino acids that is qualitatively and quantitatively the same as that found in the Murchison carbonaceous chondrite. Ultraviolet light is likely to have played a major role in prebiotic synthesis. The reaction of CO plus H2 plus NH3 on the surface of a Fischer-Tropsch catalyst produces reactive intermediates which lead to amino acids and other organic compounds in a much less efficient way than electric discharges.

  12. Evolutionary Competition Between Primitive Photosynthetic Systems: Existence of an early purple Earth?

    Science.gov (United States)

    Sparks, William B.; DasSarma, S.; Reid, I. N.

    2006-12-01

    The onset of photosynthesis in primitive cyanobacteria is thought to have profoundly altered the Earth’s atmosphere by producing an oxygen-rich atmosphere some 2 billion years ago. However, the pigments used by chlorophyll-based photosynthesis absorb at a variety of wavelengths, curiously except those centered around the peak of the Solar spectrum, 550nm. By contrast, simpler retinal-based light harvesting systems such as the haloarchaeal purple membrane bacteriorhodopsin and halorhodopsin show a strong well-defined peak of absorbance centered at 550nm. The spectroscopic complementarity for retinal pigments with chlorophyll-based pigments suggests an intriguing possibility of their co-evolution. This hypothesis argues that simpler retinal-based phototrophic capability may have evolved earlier, in microorganisms that dominated during the anaerobic and purple phase of the planet. Later, the more complex chlorophyll-based photosystem pigments could have evolved to harvest light in regions of the spectrum not absorbed by preexisting species. This would have led to the greening and oxidation of our planet and displacement of most of the retinal-based microorganisms. Not surprisingly, evidence for retinal chromoproteins have recently turned up in a variety of planktonic microorganisms. Although speculative, such a scenario would indicate that retinal-based phototrophy may be one of the oldest metabolic capabilities on Earth. Moreover, if the chlorophyll absorption spectrum is simply a product of adaptation, then its utility as a potential biomarker is likely to be limited.

  13. Verification of chemical evolution of RNA under hydrothermal environments on the primitive Earth

    Directory of Open Access Journals (Sweden)

    Kawamura Kunio

    2015-01-01

    Full Text Available The RNA World hypothesis proposes that primitive forms of life used polymers resembling RNA both as catalysts and as carriers of genetic information. It has also been suggested that the origin of life occurred in hydrothermal conditions, but this implies that the ester bonds of nucleic acids are sufficiently stable to survive in aqueous conditions at elevated temperatures. Here, we summarize the results of experimental tests of RNA in simulated hydrothermal conditions in which stability is monitored at elevated temperatures and pressures. This perspective provides insight into the evolutionary pathway from small nucleotides to functional RNA molecules and the feasibility of RNA-based life.

  14. Primitive Solar System materials and Earth share a common initial 142Nd abundance

    Science.gov (United States)

    Bouvier, A.; Boyet, M.

    2016-09-01

    The early evolution of planetesimals and planets can be constrained using variations in the abundance of neodymium-142 (142Nd), which arise from the initial distribution of 142Nd within the protoplanetary disk and the radioactive decay of the short-lived samarium-146 isotope (146Sm). The apparent offset in 142Nd abundance found previously between chondritic meteorites and Earth has been interpreted either as a possible consequence of nucleosynthetic variations within the protoplanetary disk or as a function of the differentiation of Earth very early in its history. Here we report high-precision Sm and Nd stable and radiogenic isotopic compositions of four calcium-aluminium-rich refractory inclusions (CAIs) from three CV-type carbonaceous chondrites, and of three whole-rock samples of unequilibrated enstatite chondrites. The CAIs, which are the first solids formed by condensation from the nebular gas, provide the best constraints for the isotopic evolution of the early Solar System. Using the mineral isochron method for individual CAIs, we find that CAIs without isotopic anomalies in Nd compared to the terrestrial composition share a 146Sm/144Sm-142Nd/144Nd isotopic evolution with Earth. The average 142Nd/144Nd composition for pristine enstatite chondrites that we calculate coincides with that of the accessible silicate layers of Earth. This relationship between CAIs, enstatite chondrites and Earth can only be a result of Earth having inherited the same initial abundance of 142Nd and chondritic proportions of Sm and Nd. Consequently, 142Nd isotopic heterogeneities found in other CAIs and among chondrite groups may arise from extrasolar grains that were present in the disk and incorporated in different proportions into these planetary objects. Our finding supports a chondritic Sm/Nd ratio for the bulk silicate Earth and, as a consequence, chondritic abundances for other refractory elements. It also removes the need for a hidden reservoir or for collisional erosion

  15. Primitive Solar System materials and Earth share a common initial (142)Nd abundance.

    Science.gov (United States)

    Bouvier, A; Boyet, M

    2016-09-15

    The early evolution of planetesimals and planets can be constrained using variations in the abundance of neodymium-142 ((142)Nd), which arise from the initial distribution of (142)Nd within the protoplanetary disk and the radioactive decay of the short-lived samarium-146 isotope ((146)Sm). The apparent offset in (142)Nd abundance found previously between chondritic meteorites and Earth has been interpreted either as a possible consequence of nucleosynthetic variations within the protoplanetary disk or as a function of the differentiation of Earth very early in its history. Here we report high-precision Sm and Nd stable and radiogenic isotopic compositions of four calcium-aluminium-rich refractory inclusions (CAIs) from three CV-type carbonaceous chondrites, and of three whole-rock samples of unequilibrated enstatite chondrites. The CAIs, which are the first solids formed by condensation from the nebular gas, provide the best constraints for the isotopic evolution of the early Solar System. Using the mineral isochron method for individual CAIs, we find that CAIs without isotopic anomalies in Nd compared to the terrestrial composition share a (146)Sm/(144)Sm-(142)Nd/(144)Nd isotopic evolution with Earth. The average (142)Nd/(144)Nd composition for pristine enstatite chondrites that we calculate coincides with that of the accessible silicate layers of Earth. This relationship between CAIs, enstatite chondrites and Earth can only be a result of Earth having inherited the same initial abundance of (142)Nd and chondritic proportions of Sm and Nd. Consequently, (142)Nd isotopic heterogeneities found in other CAIs and among chondrite groups may arise from extrasolar grains that were present in the disk and incorporated in different proportions into these planetary objects. Our finding supports a chondritic Sm/Nd ratio for the bulk silicate Earth and, as a consequence, chondritic abundances for other refractory elements. It also removes the need for a hidden reservoir or

  16. Rubidium isotopes in primitive chondrites: Constraints on Earth's volatile element depletion and lead isotope evolution

    Science.gov (United States)

    Nebel, O.; Mezger, K.; van Westrenen, W.

    2011-05-01

    The bulk silicate Earth (BSE) shows substantial deficits in volatile elements compared to CI-chondrites and solar abundances. These deficits could be caused by pre-accretionary depletion in the solar nebula during condensation of solids, or by later heat-driven evaporation during collision of small bodies that later accreted to form the Earth. The latter is considered to result in isotope fractionation for elements with low condensation temperatures that correlates with the degree of depletion. Here, we report first high-precision isotope ratio measurements of the moderately volatile and lithophile trace element Rb. Data from seventeen chondrite meteorites show that their Rb isotope abundances are nearly indistinguishable from Earth, not deviating more than 1 per mil in their 87Rb/85Rb. The almost uniform solar system Rb isotope pool suggests incomplete condensation or evaporation in a single stage is unlikely to be the cause of the volatile element deficit of the Earth. As Rb and Pb have similar condensation temperatures, we use their different degrees of depletion in the BSE to address the mechanisms and timing of terrestrial volatile depletion. The Rb isotope data are consistent with a scenario in which the volatile budget of the Earth was generated by a mixture of a highly volatile-element depleted early Proto-Earth with undepleted material in the course of terrestrial accretion. Observed Pb and Rb abundances and U-Pb and Rb-Sr isotope systematics suggest that volatile addition occurred at approximately the same time at which last core-mantle equilibration was achieved. In line with previous suggestions, this last equilibration involved a second stage of Pb (but not Rb) depletion from the BSE. The timing of this second Pb loss event can be constrained to ~ 110 Ma after the start of the solar system. This model supports a scenario with core storage of Pb in the aftermath of a putative Moon forming giant impact that also delivered the bulk of the volatile

  17. Evaluation of Big Data Containers for Popular Storage, Retrieval, and Computation Primitives in Earth Science Analysis

    Science.gov (United States)

    Das, K.; Clune, T.; Kuo, K. S.; Mattmann, C. A.; Huang, T.; Duffy, D.; Yang, C. P.; Habermann, T.

    2015-12-01

    Data containers are infrastructures that facilitate storage, retrieval, and analysis of data sets. Big data applications in Earth Science require a mix of processing techniques, data sources and storage formats that are supported by different data containers. Some of the most popular data containers used in Earth Science studies are Hadoop, Spark, SciDB, AsterixDB, and RasDaMan. These containers optimize different aspects of the data processing pipeline and are, therefore, suitable for different types of applications. These containers are expected to undergo rapid evolution and the ability to re-test, as they evolve, is very important to ensure the containers are up to date and ready to be deployed to handle large volumes of observational data and model output. Our goal is to develop an evaluation plan for these containers to assess their suitability for Earth Science data processing needs. We have identified a selection of test cases that are relevant to most data processing exercises in Earth Science applications and we aim to evaluate these systems for optimal performance against each of these test cases. The use cases identified as part of this study are (i) data fetching, (ii) data preparation for multivariate analysis, (iii) data normalization, (iv) distance (kernel) computation, and (v) optimization. In this study we develop a set of metrics for performance evaluation, define the specifics of governance, and test the plan on current versions of the data containers. The test plan and the design mechanism are expandable to allow repeated testing with both new containers and upgraded versions of the ones mentioned above, so that we can gauge their utility as they evolve.

  18. Organic matter in the Titan lakes, and comparison with primitive Earth

    Science.gov (United States)

    Khare, Bishun N.; McKay, C.; Wilhite, P.; Beeler, D.; Carter, M.; Schurmeier, L.; Jagota, S.; Kawai, J.; Nna-Mvondo, D.; Cruikshank, D.; Embaye, T.

    2013-06-01

    Titan is the only world in the solar system besides the Earth that has liquid on its surface. The liquid in the lakes is thought to be composed primarily of ethane with methane and nitrogen in solution. The clouds are thought to be composed of liquid methane drops. Surface liquid is present in polar lakes and in surface materials at equatorial sites. Studying the chemical processing that potentially results from organic material interacting with this liquid is one of the main goals of proposed missions to Titan. We have been engaged in producing tholin under Titan-like conditions for more than three decades, first at the Laboratory for Planetary Studies at Cornell University in collaboration with Late Dr. Carl Sagan and for over a decade at Laboratory for Planetary Studies at NASA Ames Research Center and Carl Sagan Center for the Study of Life in the Universe, SETI Institute. Our focus is to understand the capabilities for analysis of tholin solubility in liquid methane and ethane for flight instruments. Our results are expected to contribute to an understanding of the organic chemistry on Titan and to the development of an explicit and targeted scientific strategy for near term analysis of the products of organic-liquid interactions on Titan. Organics are produced as a haze in Titan's high atmosphere due to photolysis of methane with the Sun's extreme ultraviolet light and subsequent reaction with N. Also tholins are formed at a much higher level on Titan by charged particles of Saturn magnetosphere. However, the presence of organics is not the sole feature, which makes Titan significant to astrobiology; organics are widely present in the outer solar system. The reason Titan is a prime target for future outer solar system missions is the combination of organic material and liquid on the surface; liquid that could over a medium for further organic synthesis. NASA recently selected for further study a Discovery proposal TiME to investigate the chemistry of the

  19. Looking for plausibility

    CERN Document Server

    Abdullah, Wan Ahmad Tajuddin Wan

    2010-01-01

    In the interpretation of experimental data, one is actually looking for plausible explanations. We look for a measure of plausibility, with which we can compare different possible explanations, and which can be combined when there are different sets of data. This is contrasted to the conventional measure for probabilities as well as to the proposed measure of possibilities. We define what characteristics this measure of plausibility should have. In getting to the conception of this measure, we explore the relation of plausibility to abductive reasoning, and to Bayesian probabilities. We also compare with the Dempster-Schaefer theory of evidence, which also has its own definition for plausibility. Abduction can be associated with biconditionality in inference rules, and this provides a platform to relate to the Collins-Michalski theory of plausibility. Finally, using a formalism for wiring logic onto Hopfield neural networks, we ask if this is relevant in obtaining this measure.

  20. Primitive Associations

    DEFF Research Database (Denmark)

    Ernst, Erik

    2007-01-01

    This position paper presents a very simple mechanism, primitive associations, and argues that this mechanism is worth careful consideration in connection with the kind of support for program correctness that grows out of mechanisms for ownership, controlled aliasing, sharing, escape analysis...

  1. Prebiotic Synthesis of Methionine and Other Sulfur-Containing Organic Compounds on the Primitive Earth: A Contemporary Reassessment Based on an Unpublished 1958 Stanley Miller Experiment

    Science.gov (United States)

    Parker, Eric T.; Cleaves, H. James; Callahan, Michael P.; Dworkin, Jason P.; Glavin, Daniel P.; Lazcano, Antonio

    2010-01-01

    Original extracts from an unpublished 1958 experiment conducted by the late Stanley L. Miller were recently found and analyzed using modern state-of-the-art analytical methods. The extracts were produced by the action of an electric discharge on a mixture of methane (CH4), hydrogen sulfide (H2S), ammonia (NH3), and carbon dioxide (CO2). Racemic methionine was farmed in significant yields, together with other sulfur-bearing organic compounds. The formation of methionine and other compounds from a model prebiotic atmosphere that contained H2S suggests that this type of synthesis is robust under reducing conditions, which may have existed either in the global primitive atmosphere or in localized volcanic environments on the early Earth. The presence of a wide array of sulfur-containing organic compounds produced by the decomposition of methionine and cysteine indicates that in addition to abiotic synthetic processes, degradation of organic compounds on the primordial Earth could have been important in diversifying the inventory of molecules of biochemical significance not readily formed from other abiotic reactions, or derived from extraterrestrial delivery.

  2. Is it plausible to expect a close encounter of the Earth with a yet undiscovered astronomical object in the next few years?

    CERN Document Server

    Iorio, Lorenzo

    2010-01-01

    We analytically and numerically investigate the possibility that a still undiscovered body X, moving along an unbound hyperbolic path from outside the solar system, may penetrate its inner regions in the next few years posing a threat to the Earth. By conservatively using as initial position the lower bounds on the present-day distance dX of X dynamically inferred from the gravitational perturbations induced by it on the orbital motions of the planets of the solar system, both the analyses show that, in order to reach the Earth's orbit in the next 2 yr, X should move at a highly unrealistic speed v, whatever its mass MX is. For example, by assuming for it a solar (MX =M_Sun) or brown dwarf mass (MX = 80mJup), now at not less than dX = 11-6 kau (1 kau=1000 astronomical units), v would be of the order of 6-10% and 3-5% of the speed of light c, respectively. By assuming larger present-day distances for X, on the basis of the lacking of direct observational evidences of electromagnetic origin for it, its speed wo...

  3. Primitive Virtual Negative Charge

    CERN Document Server

    Kim, Kiyoung

    2008-01-01

    Physical fields, such as gravity and electromagnetic field, are interpreted as results from rearrangement of vacuum particles to get the equilibrium of net charge density and net mass density in 4-dimensional complex space. Then, both fields should interact to each other in that physical interaction is considered as a field-to-field interaction. Hence, Mass-Charge interaction is introduced with primitive-virtual negative charge defined for the mass. With the concept of Mass-Charge interaction electric equilibrium of the earth is discussed, especially about the electric field and magnetic field of the earth. For unsettled phenomena related with the earth's gravity, such as antigravity phenomenon, gravity anomalies during the solar eclipses, the connection between geomagnetic storms and earthquakes, etc., possible explanations are discussed.

  4. Primitive helium in diamonds

    Science.gov (United States)

    Ozima, M.; Zashu, S.

    1983-03-01

    He-3/He-4 isotopic ratio analyses of 13 diamond stones from unspecified mines in South Africa yield values ranging from less than 10 to the -7th to 0.00032 + or - 0.000025. The latter value is higher than the primordial He-3/He-4 ratio in meteorites, and close to the ratio for solar type He. It is suggested that these elevated values may represent primitive He which has evolved little, in view of its minute increase in radiogenic He-4, since the earth's formation.

  5. Major element composition of an Early Enriched Reservoir: constraints from 142Nd/144Nd isotope systematics in the early Earth and high-pressure melting experiments of a primitive peridotite

    Science.gov (United States)

    Kondo, Nozomi; Yoshino, Takashi; Matsukage, Kyoko N.; Kogiso, Tetsu

    2016-12-01

    The Accessible Silicate Earth (ASE) has a higher 142Nd/144Nd ratio than most chondrites. Thus, if the Earth is assumed to have formed from these chondrites, a complement low-142Nd/144Nd reservoir is needed. Such a low-142Nd/144Nd reservoir is believed to have been derived from a melt in the early Earth and is called the Early Enriched Reservoir (EER). Although the major element composition of the EER is crucial for estimating its chemical and physical properties (e.g., density) and is also essential for understanding the origin and fate of the EER, which are both major factors that determine the present composition of the Earth, it has not yet been robustly established. In order to determine the major element composition of the EER, we estimated the age and pressure-temperature conditions to form the EER that would best explain its Nd isotopic characteristics, based on Sm-Nd partitioning and its dependence on pressure, temperature, and melting phase relations. Our estimate indicates that the EER formed within 33.5 Myr of Solar System formation and at near-solidus temperatures and shallow upper-mantle pressures. We then performed high-pressure melting experiments on primitive peridotite to determine the major element composition of the EER at estimated temperature at 7 GPa and calculated the density of the EER. The result of our experiments indicates that the near-solidus melt is iron-rich komatiite. The estimated density of the near-solidus melt is lower than that of the primitive peridotite, suggesting that the EER melt would have ascended in the mantle to form an early crust. Given that high mantle potential temperatures are assumed to have existed in the Hadean, it follows that the EER melt was generated at high pressure and, therefore, its composition would have been picritic to komatiitic. As the formation age of the EER estimated in our study precedes the last giant, lunar-forming impact, the picritic to komatiitic crust (EER) would most likely have been

  6. Renal primitive neuroectodermal tumors.

    Science.gov (United States)

    Bartholow, Tanner; Parwani, Anil

    2012-06-01

    Primitive neuroectodermal tumors exist as a part of the Ewing sarcoma/primitive neuroectodermal tumor family. These tumors most commonly arise in the chest wall and paraspinal regions; cases with a renal origin are rare entities, but have become increasingly reported in recent years. Although such cases occur across a wide age distribution, the average age for a patient with a renal primitive neuroectodermal tumor is the mid- to late 20s, with both males and females susceptible. Histologically, these tumors are characterized by pseudorosettes. Immunohistochemically, CD99 is an important diagnostic marker. Clinically, these are aggressive tumors, with an average 5-year disease-free survival rate of only 45% to 55%. Given that renal primitive neuroectodermal tumor bears many similarities to other renal tumors, it is important to review the histologic features, immunostaining profile, and genetic abnormalities that can be used for its correct diagnosis.

  7. Uterine primitive neuroectodermal tumor.

    Science.gov (United States)

    Aminimoghaddam, Soheila; Seifirad, Soroush; Abbasi Dezfouli, Golbahar; Abbasi, Neda; Zare Mehrjardi, Ali; Razavi, Seyed Mohsen; Mahmoudzadeh, Fatemeh

    2015-04-01

    Primitive neuroectodermal tumors are fairly rare in uterus. A case of uterine body primitive neuroectodermal tumor in a 32-year-old Iranian woman is presented. The patient was admitted with abdominal pain and fever and underwent emergency exploratory surgery with total abdominal hysterectomy, bilateral salpingo-oophorectomy, and pelvic lymph node dissection. Posterior wall of the uterus was necrotic and ruptured and a huge tumor disrupted the uterine body. The tumor was strongly positive for CD99, NSE, and chromogranin; No reaction was seen for CD10, CD45 and myogenin. To the best of our knowledge, this is the first report of an uterine body primitive neuroectodermal tumor and the second report of uterine primitive neuroectodermal tumor from Iran.

  8. Workshop: Teaching Primitive Arts.

    Science.gov (United States)

    Jordison, Jerry

    1999-01-01

    Discusses the concrete and spiritual aspects of teaching workshops on survival skills or primitive arts. Gives details on lostproofing, or ways to teach a child not to get lost in the outdoors; building a survival shelter; and wilderness cooking. (CDS)

  9. Chemical evolution of primitive solar system bodies

    Science.gov (United States)

    Oro, J.; Mills, T.

    1989-01-01

    Observations on organic molecules and compounds containing biogenic elements in the interstellar medium and in the primitive bodies of the solar system are reviewed. The discovery of phosphorus molecular species in dense interstellar clouds, the existence of organic ions in the dust and gas phase of the comas of Comet Halley, and the presence of presolar, deuterium-hydrogen ratios in the amino acids of carbonaceous chondrites are discussed. The relationships between comets, dark asteroids, and carbonaceous chondrites are examined. Also, consideration is given to the chemical evolution of Titan, the primitive earth, and early Mars.

  10. De novo synthesis and functional study of primitive polypeptides in the prebiotic protein world

    Science.gov (United States)

    Fujishima, Kosuke; Wang, Kendrick; Ferreira, Raphael; Rothschild, Lynn

    DNA, RNA and proteins within a lipid-bound membrane are the core components of life, but the order of their appearance during the origin and evolution of life is still under debate. The widely accepted “RNA World” hypothesis states that RNA likely emerged prior to proteins and DNA since RNA can serve both replicative and catalytic roles. While biochemists have reproduced the synthesis, polymerization, and replication of nucleotides/RNA under controlled prebiotic conditions, such complex organic molecules were not present in significant amounts on the prebiotic Earth. In contrast, amino acids are naturally abundant in various prebiotic contexts such as carbonaceous chondrites and Urey-Miller type experiments, and many studies have demonstrated plausible prebiotic conditions that could condense/polymerize amino acids to give rise to short peptides. These findings support the basis of a “Protein World” hypothesis for life, however little has been done to study the functions of such primitive peptides. Here, we present a novel synthetic biology-based approach to the de novo synthesis of over billions of primitive peptides/proteins derived from a limited set of naturally abundant proteinogenic amino acids. Of these peptides, ones with divalent metal-binding capability are of particular interest and will be screened and identified. Certain divalent metals are likely present in prebiotic environments and both coordinate well with amino acids and catalyze reactions, which are difficult to achieve in organic chemistry. Furthermore, since D-chiral and non-proteinogenic amino acids are also abundant in the universe and may provide insight into the pathway by which life developed, the methods to analyze primitive peptides consisting of these amino acids will be discussed. By understanding this natural pathway, we will be able to better understand how life developed here on Earth and the probability of life arising elsewhere.

  11. PRIMitive Asteroids Spectroscopic Survey - PRIMASS: First Results

    Science.gov (United States)

    de Leon, Julia; Pinilla-Alonso, Noemi; Campins, Humberto; Lorenzi, Vania; Licandro, Javier; Morate, David; Tanga, Paolo; Cellino, Alberto; Delbo, Marco

    2015-11-01

    NASA OSIRIS-REx and JAXA Hayabusa 2 sample-return missions have targeted two near-Earth asteroids: (101955) Bennu and (162173) 1999 JU3, respectively. These are primitive asteroids that are believed to originate in the inner belt, where five distinct sources have been identified: four primitive collisional families (Polana, Erigone, Sulamitis, and Clarissa), and a population of low-albedo and low-inclination background asteroids. Identifying and characterizing the populations from which these two NEAs might originate will enchance the science return of the two missions.With this main objective in mind, we initiated in 2010 a spectroscopic survey in the visible and the near-infrared to characterize the primitive collisional families in the inner belt and the low-albedo background population. This is the PRIMitive Asteroids Spectroscopic Survey - PRIMASS. So far we have obtained more than 200 spectra using telescopes located at different observatories. PRIMASS uses a variety of ground based facilities. Most of the spectra have been obtained using the 10.4m Gran Telescopio Canarias (GTC), and the 3.6m Telescopio Nazionale Galileo (TNG), both located at the El Roque de los Muchachos Observatory (La Palma, Spain), and the 3.0m NASA Infrared Telescope Facility on Mauna Kea (Hawai, USA).We present the first results from our on-going survey (de Leon et al. 2015; Pinilla-Alonso et al. 2015; Morate et al. 2015), focused on the Polana and the Erigone primitive families, with visible and near-infrared spectra of more than 200 objects, most of them with no previous spectroscopic data. Our survey is already the largest database of primitive asteroids spectra, and we keep obtaining data on the Sulamitis and the Clarissa families, as well as on the background low-albedo population.

  12. [Jaws of primitive mammals].

    Science.gov (United States)

    Tsubamoto, Takehisa

    2005-06-01

    Some of main osteological differences between mammals and reptiles are seen in the number of bones that constitute lower jaw and in jaw articulation. A lower jaw of mammals consists of only one bone, while in reptiles it consists of several bones (e.g., four to six in lizards and five in crocodiles). The jaw articulation in mammals is performed by squamosal of the skull and the mandible ( = dentary), while in reptiles it is done by quadrate of the skull and articular of the lower jaw. When mammals first appeared about 200 million years ago in the Mesozoic Era, the jaws of primitive mammals were morphologically intermediate between those of reptiles and typical mammals. Here, I briefly introduce the evolution of lower jaw morphology from the reptilian one to the mammalian one, showing lower jaw features of some mammal-like reptiles and primitive mammals.

  13. Action Recognition using Motion Primitives

    DEFF Research Database (Denmark)

    Moeslund, Thomas B.; Fihl, Preben; Holte, Michael Boelstoft

    The number of potential applications has made automatic recognition of human actions a very active research area. Different approaches have been followed based on trajectories through some state space. In this paper we also model an action as a trajectory through a state space, but we represent...... the actions as a sequence of temporal isolated instances, denoted primitives. These primitives are each defined by four features extracted from motion images. The primitives are recognized in each frame based on a trained classifier resulting in a sequence of primitives. From this sequence we recognize...

  14. Earth

    CERN Document Server

    Carter, Jason

    2017-01-01

    This curriculum-based, easy-to-follow book teaches young readers about Earth as one of the eight planets in our solar system in astronomical terms. With accessible text, it provides the fundamental information any student needs to begin their studies in astronomy, such as how Earth spins and revolves around the Sun, why it's uniquely suitable for life, its physical features, atmosphere, biosphere, moon, its past, future, and more. To enhance the learning experience, many of the images come directly from NASA. This straightforward title offers the fundamental information any student needs to sp

  15. What can we learn from Plausible Values?

    Science.gov (United States)

    Marsman, Maarten; Maris, Gunter; Bechger, Timo; Glas, Cees

    2016-06-01

    In this paper, we show that the marginal distribution of plausible values is a consistent estimator of the true latent variable distribution, and, furthermore, that convergence is monotone in an embedding in which the number of items tends to infinity. We use this result to clarify some of the misconceptions that exist about plausible values, and also show how they can be used in the analyses of educational surveys.

  16. Primitive neuroectodermal tumor: CT findings

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Chang Soo; Eun, Tchoong Kie; Cha, Seong Sook; Han, Sang Suk; Chung, Duck Hwan [Inje College, Paik Hospital, Busan (Korea, Republic of)

    1987-04-15

    Primitive neuroectodermal tumor is a neoplasm of young individuals that occurs predominantly in the supratentorial compartment. Authors experienced three cases of primitive neuroectodermal tumor. On the brain CT scans, all three cases reveal the large, irregular, hyperdense mass lesions with calcifications and cystic or necrotic areas, and show dense heterogeneous contrast enhancement.

  17. Unsupervised Learning of Action Primitives

    DEFF Research Database (Denmark)

    Baby, Sanmohan; Krüger, Volker; Kragic, Danica

    2010-01-01

    Action representation is a key issue in imitation learning for humanoids. With the recent finding of mirror neurons there has been a growing interest in expressing actions as a combination meaningful subparts called primitives. Primitives could be thought of as an alphabet for the human actions. ...

  18. Plausibility functions and exact frequentist inference

    CERN Document Server

    Martin, Ryan

    2012-01-01

    In the frequentist program, inferential methods with exact control on error rates are a primary focus. Methods based on asymptotic distribution theory may not be suitable in a particular problem, in which case, a numerical method is needed. This paper presents a general, Monte Carlo-driven framework for the construction of frequentist procedures based on plausibility functions. It is proved that the suitably defined plausibility function-based tests and confidence regions have desired frequentist properties. Moreover, in an important special case involving likelihood ratios, conditions are given such that the plausibility function behaves asymptotically like a consistent Bayesian posterior distribution. An extension of the proposed method is also given for the case where nuisance parameters are present. A number of examples are given which illustrate the method and demonstrate its strong performance compared to other popular existing methods.

  19. Bisimulation for Single-Agent Plausibility Models

    DEFF Research Database (Denmark)

    Andersen, Mikkel Birkegaard; Bolander, Thomas; van Ditmarsch, H.;

    2013-01-01

    Epistemic plausibility models are Kripke models agents use to reason about the knowledge and beliefs of themselves and each other. Restricting ourselves to the single-agent case, we determine when such models are indistinguishable in the logical language containing conditional belief, i.e., we...... define a proper notion of bisimulation, and prove that bisimulation corresponds to logical equivalence on image-finite models. We relate our results to other epistemic notions, such as safe belief and degrees of belief. Our results imply that there are only finitely many non-bisimilar single......-agent epistemic plausibility models on a finite set of propositions. This gives decidability for single-agent epistemic plausibility planning....

  20. The organic inventory of primitive meteorites

    Science.gov (United States)

    Martins, Zita

    Carbonaceous meteorites are primitive samples that provide crucial information about the solar system genesis and evolution. This class of meteorites has also a rich organic inventory, which may have contributed the first prebiotic building blocks of life to the early Earth. We have studied the soluble organic inventory of several CR and CM meteorites, using high performance liquid chromatography with UV fluorescence detection (HPLC-FD), gas chromatography-mass spectrometry (GC-MS) and gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). Our target organic molecules include amino acids, nucleobases and polycyclic aromatic hydrocarbons (PAHs), among others. CR chondrites contain the highest amino acids concentration ever detected in a meteorite. The degree of aqueous alteration amongst this class of meteorites seems to be responsible for the amino acid distribution. Pioneering compound-specific carbon isotope measurements of nucleobases present in carbonaceous chondrites show that these compounds have a non-terrestrial origin. This suggests that components of the ge-netic code may have had a crucial role in life's origin. Investigating the abundances, distribution and isotopic composition of organic molecules in primitive meteorites significantly improves our knowledge of the chemistry of the early solar system, and the resources available for the first living organisms on Earth.

  1. Motion Primitives for Action Recognition

    DEFF Research Database (Denmark)

    Fihl, Preben; Holte, Michael Boelstoft; Moeslund, Thomas B.

    2007-01-01

    The number of potential applications has made automatic recognition of human actions a very active research area. Different approaches have been followed based on trajectories through some state space. In this paper we also model an action as a trajectory through a state space, but we represent...... the actions as a sequence of temporal isolated instances, denoted primitives. These primitives are each defined by four features extracted from motion images. The primitives are recognized in each frame based on a trained classifier resulting in a sequence of primitives. From this sequence we recognize...... different temporal actions using a probabilistic Edit Distance method. The method is tested on different actions with and without noise and the results show recognition rates of 88.7% and 85.5%, respectively....

  2. Unsupervised Learning of Action Primitives

    DEFF Research Database (Denmark)

    Baby, Sanmohan; Krüger, Volker; Kragic, Danica

    2010-01-01

    and scale, the use of the object can provide a strong invariant for the detection of motion primitives. In this paper we propose an unsupervised learning approach for action primitives that makes use of the human movements as well as the object state changes. We group actions according to the changes......Action representation is a key issue in imitation learning for humanoids. With the recent finding of mirror neurons there has been a growing interest in expressing actions as a combination meaningful subparts called primitives. Primitives could be thought of as an alphabet for the human actions....... In this paper we observe that human actions and objects can be seen as being intertwined: we can interpret actions from the way the body parts are moving, but as well from how their effect on the involved object. While human movements can look vastly different even under minor changes in location, orientation...

  3. Biologically Plausible, Human-scale Knowledge Representation

    Science.gov (United States)

    Crawford, Eric; Gingerich, Matthew; Eliasmith, Chris

    2016-01-01

    Several approaches to implementing symbol-like representations in neurally plausible models have been proposed. These approaches include binding through synchrony (Shastri & Ajjanagadde, 1993), "mesh" binding (van der Velde & de Kamps, 2006), and conjunctive binding (Smolensky, 1990). Recent theoretical work has suggested that…

  4. AGUA TIBIA PRIMITIVE AREA, CALIFORNIA.

    Science.gov (United States)

    Irwin, William P.; Thurber, Horace K.

    1984-01-01

    The Agua Tibia Primitive Area in southwestern California is underlain by igneous and metamorphic rocks that are siilar to those widely exposed throughout much of the Peninsular Ranges. To detect the presence of any concealed mineral deposits, samples of stream sediments were collected along the various creeks that head in the mountain. As an additional aid in evaluating the mineral potential, an aeromagnetic survey was made and interpreted. A search for records of past or existing mining claims within the primitive area was made but none was found. Evidence of deposits of metallic or nonmetallic minerals was not seen during the study.

  5. Standards for Graph Algorithm Primitives

    OpenAIRE

    Mattson, Tim; Bader, David; Berry, Jon; Buluc, Aydin; Dongarra, Jack; Faloutsos, Christos; Feo, John; Gilbert, John; Gonzalez, Joseph; Hendrickson, Bruce; Kepner, Jeremy; Leiserson, Charles; Lumsdaine, Andrew; Padua, David; Poole, Stephen

    2014-01-01

    It is our view that the state of the art in constructing a large collection of graph algorithms in terms of linear algebraic operations is mature enough to support the emergence of a standard set of primitive building blocks. This paper is a position paper defining the problem and announcing our intention to launch an open effort to define this standard.

  6. Neuroradiology of primitive neuroectodermal tumors

    Energy Technology Data Exchange (ETDEWEB)

    Hinshaw, D.B. Jr.; Thompson, J.R.; Hasso, A.N.; Ashwal, S.

    1983-05-01

    The neuroradiological findings in four cases of primitive neuroectodermal tumor of the cerebrum are described. These highly malignant neoplasms of childhood present as large, enhancing cerebral masses with extensive neovascularity. Cerebrospinal fluid seeding is common and distant extraneural metastases may occur.

  7. Primitive Based Action Representation and Recognition

    DEFF Research Database (Denmark)

    Baby, Sanmohan; Krüger, Volker

    2009-01-01

    There has been a recent interest in segmenting action sequences into   meaningful parts (action primitives) and to model actions on a   higher level based on these action primitives. Unlike previous works where action primitives are defined    a-priori and search is made for them later, we presen...

  8. Primitive Based Action Representation and Recognition

    DEFF Research Database (Denmark)

    Baby, Sanmohan; Krüger, Volker

    2009-01-01

    There has been a recent interest in segmenting action sequences into   meaningful parts (action primitives) and to model actions on a   higher level based on these action primitives. Unlike previous works where action primitives are defined    a-priori and search is made for them later, we presen...

  9. A Proof-Theoretic Account of Primitive Recursion and Primitive Iteration

    DEFF Research Database (Denmark)

    Cherabini, Luca; Danvy, Olivier

    2011-01-01

    We revisit both the usual ``going-up'' induction principle and Manna and Waldinger's ``going-down'' induction principle for primitive recursion,`a la Goedel, and primitive iteration, `a la Church. We use 'Kleene's trick' to show that primitive recursion and primitive iiteration are as expressive ...

  10. A Proof-Theoretic Account of Primitive Recursion and Primitive Iteration

    DEFF Research Database (Denmark)

    Cherabini, Luca; Danvy, Olivier

    2011-01-01

    We revisit both the usual ``going-up'' induction principle and Manna and Waldinger's ``going-down'' induction principle for primitive recursion,`a la Goedel, and primitive iteration, `a la Church. We use 'Kleene's trick' to show that primitive recursion and primitive iiteration are as expressive...

  11. Anatomically Plausible Surface Alignment and Reconstruction

    DEFF Research Database (Denmark)

    Paulsen, Rasmus R.; Larsen, Rasmus

    2010-01-01

    With the increasing clinical use of 3D surface scanners, there is a need for accurate and reliable algorithms that can produce anatomically plausible surfaces. In this paper, a combined method for surface alignment and reconstruction is proposed. It is based on an implicit surface representation...... combined with a Markov Random Field regularisation method. Conceptually, the method maintains an implicit ideal description of the sought surface. This implicit surface is iteratively updated by realigning the input point sets and Markov Random Field regularisation. The regularisation is based on a prior...... energy that has earlier proved to be particularly well suited for human surface scans. The method has been tested on full cranial scans of ten test subjects and on several scans of the outer human ear....

  12. Primary renal primitive neuroectodermal tumor.

    Science.gov (United States)

    Goel, V; Talwar, V; Dodagoudar, C; Singh, S; Sharma, A; Patnaik, N

    2015-01-01

    Primitive Neuroectodermal Tumor of the kidney is a rare entity. Very few cases of primary renal PNET have been reported to date. Most literature about rPNET is isolated case reports. We report a case of rPNET in a 39-year-old male with a pre-operative diagnosis of renal cell carcinoma with renal vein thrombosis. The patient underwent radical nephrectomy with thrombolectomy, and histopathological examination revealed a highly aggressive tumor composed of monotonous sheets of round cells. Tumor cells were positive for CD 99 and FLI-1, hence confirming the diagnosis of Primitive Neuroectodermal Tumor. Post-surgery, patient was given VAC/IE-based adjuvant chemotherapy. In view of highly aggressive nature of this tumor, prompt diagnosis and imparting effective chemotherapy regimen to the patient is required, and it is important to differentiate PNET from other small round-cell tumors because of different therapeutic approach.

  13. Finite, primitive and euclidean spaces

    Directory of Open Access Journals (Sweden)

    Efim Khalimsky

    1988-01-01

    Full Text Available Integer and digital spaces are playing a significant role in digital image processing, computer graphics, computer tomography, robot vision, and many other fields dealing with finitely or countable many objects. It is proven here that every finite T0-space is a quotient space of a subspace of some simplex, i.e. of some subspace of a Euclidean space. Thus finite and digital spaces can be considered as abstract simplicial structures of subspaces of Euclidean spaces. Primitive subspaces of finite, digital, and integer spaces are introduced. They prove to be useful in the investigation of connectedness structure, which can be represented as a poset, and also in consideration of the dimension of finite spaces. Essentially T0-spaces and finitely connected and primitively path connected spaces are discussed.

  14. The Role of Plausible Values in Large-Scale Surveys

    Science.gov (United States)

    Wu, Margaret

    2005-01-01

    In large-scale assessment programs such as NAEP, TIMSS and PISA, students' achievement data sets provided for secondary analysts contain so-called "plausible values." Plausible values are multiple imputations of the unobservable latent achievement for each student. In this article it has been shown how plausible values are used to: (1) address…

  15. Comprehending Conflicting Science-Related Texts: Graphs as Plausibility Cues

    Science.gov (United States)

    Isberner, Maj-Britt; Richter, Tobias; Maier, Johanna; Knuth-Herzig, Katja; Horz, Holger; Schnotz, Wolfgang

    2013-01-01

    When reading conflicting science-related texts, readers may attend to cues which allow them to assess plausibility. One such plausibility cue is the use of graphs in the texts, which are regarded as typical of "hard science." The goal of our study was to investigate the effects of the presence of graphs on the perceived plausibility and…

  16. Invariant visual object recognition: biologically plausible approaches.

    Science.gov (United States)

    Robinson, Leigh; Rolls, Edmund T

    2015-10-01

    Key properties of inferior temporal cortex neurons are described, and then, the biological plausibility of two leading approaches to invariant visual object recognition in the ventral visual system is assessed to investigate whether they account for these properties. Experiment 1 shows that VisNet performs object classification with random exemplars comparably to HMAX, except that the final layer C neurons of HMAX have a very non-sparse representation (unlike that in the brain) that provides little information in the single-neuron responses about the object class. Experiment 2 shows that VisNet forms invariant representations when trained with different views of each object, whereas HMAX performs poorly when assessed with a biologically plausible pattern association network, as HMAX has no mechanism to learn view invariance. Experiment 3 shows that VisNet neurons do not respond to scrambled images of faces, and thus encode shape information. HMAX neurons responded with similarly high rates to the unscrambled and scrambled faces, indicating that low-level features including texture may be relevant to HMAX performance. Experiment 4 shows that VisNet can learn to recognize objects even when the view provided by the object changes catastrophically as it transforms, whereas HMAX has no learning mechanism in its S-C hierarchy that provides for view-invariant learning. This highlights some requirements for the neurobiological mechanisms of high-level vision, and how some different approaches perform, in order to help understand the fundamental underlying principles of invariant visual object recognition in the ventral visual stream.

  17. SYCAMORE CANYON PRIMITIVE AREA, ARIZONA.

    Science.gov (United States)

    Huff, Lyman C.; Raabe, R.C.

    1984-01-01

    The Sycamore Canyon Primitive Area, which occupies about 74 sq mi, lies about 24 mi southwest of Flagstaff, Arizona. To help evaluate the area for mineral resources, sediment samples were collected along Sycamore Creek and its tributaries. These were analyzed for traces of the ore metals without finding any local concentrations. In addition, a scintillometer was used to test rocks in the area without finding any abnormal radioactivity.

  18. Plausibility and evidence: the case of homeopathy.

    Science.gov (United States)

    Rutten, Lex; Mathie, Robert T; Fisher, Peter; Goossens, Maria; van Wassenhoven, Michel

    2013-08-01

    Homeopathy is controversial and hotly debated. The conclusions of systematic reviews of randomised controlled trials of homeopathy vary from 'comparable to conventional medicine' to 'no evidence of effects beyond placebo'. It is claimed that homeopathy conflicts with scientific laws and that homoeopaths reject the naturalistic outlook, but no evidence has been cited. We are homeopathic physicians and researchers who do not reject the scientific outlook; we believe that examination of the prior beliefs underlying this enduring stand-off can advance the debate. We show that interpretations of the same set of evidence--for homeopathy and for conventional medicine--can diverge. Prior disbelief in homeopathy is rooted in the perceived implausibility of any conceivable mechanism of action. Using the 'crossword analogy', we demonstrate that plausibility bias impedes assessment of the clinical evidence. Sweeping statements about the scientific impossibility of homeopathy are themselves unscientific: scientific statements must be precise and testable. There is growing evidence that homeopathic preparations can exert biological effects; due consideration of such research would reduce the influence of prior beliefs on the assessment of systematic review evidence.

  19. Analytic Models of Plausible Gravitational Lens Potentials

    Energy Technology Data Exchange (ETDEWEB)

    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.

  20. Stardust silicates from primitive meteorites.

    Science.gov (United States)

    Nagashima, Kazuhide; Krot, Alexander N; Yurimoto, Hisayoshi

    2004-04-29

    Primitive chondritic meteorites contain material (presolar grains), at the level of a few parts per million, that predates the formation of our Solar System. Astronomical observations and the chemical composition of the Sun both suggest that silicates must have been the dominant solids in the protoplanetary disk from which the planets of the Solar System formed, but no presolar silicates have been identified in chondrites. Here we report the in situ discovery of presolar silicate grains 0.1-1 microm in size in the matrices of two primitive carbonaceous chondrites. These grains are highly enriched in 17O (delta17O(SMOW) > 100-400 per thousand ), but have solar silicon isotopic compositions within analytical uncertainties, suggesting an origin in an oxygen-rich red giant or an asymptotic giant branch star. The estimated abundance of these presolar silicates (3-30 parts per million) is higher than reported for other types of presolar grains in meteorites, consistent with their ubiquity in the early Solar System, but is about two orders of magnitude lower than their abundance in anhydrous interplanetary dust particles. This result is best explained by the destruction of silicates during high-temperature processing in the solar nebula.

  1. Primitives for Contract-based Synchronization

    CERN Document Server

    Bartoletti, Massimo; 10.4204/EPTCS.38.8

    2010-01-01

    We investigate how contracts can be used to regulate the interaction between processes. To do that, we study a variant of the concurrent constraints calculus presented in [1], featuring primitives for multi-party synchronization via contracts. We proceed in two directions. First, we exploit our primitives to model some contract-based interactions. Then, we discuss how several models for concurrency can be expressed through our primitives. In particular, we encode the pi-calculus and graph rewriting.

  2. Primitives for Contract-based Synchronization

    Directory of Open Access Journals (Sweden)

    Massimo Bartoletti

    2010-10-01

    Full Text Available We investigate how contracts can be used to regulate the interaction between processes. To do that, we study a variant of the concurrent constraints calculus presented in [1], featuring primitives for multi-party synchronization via contracts. We proceed in two directions. First, we exploit our primitives to model some contract-based interactions. Then, we discuss how several models for concurrency can be expressed through our primitives. In particular, we encode the pi-calculus and graph rewriting.

  3. Encoding the target or the plausible preview word? The nature of the plausibility preview benefit in reading Chinese.

    Science.gov (United States)

    Yang, Jinmian; Li, Nan; Wang, Suiping; Slattery, Timothy J; Rayner, Keith

    2014-01-01

    Previous studies have shown that a plausible preview word can facilitate the processing of a target word as compared to an implausible preview word (a plausibility preview benefit effect) when reading Chinese (Yang, Wang, Tong, & Rayner, 2012; Yang, 2013). Regarding the nature of this effect, it is possible that readers processed the meaning of the plausible preview word and did not actually encode the target word (given that the parafoveal preview word lies close to the fovea). The current experiment examined this possibility with three conditions wherein readers received a preview of a target word that was either (1) identical to the target word (identical preview), (2) a plausible continuation of the pre-target text, but the post-target text in the sentence was incompatible with it (initially plausible preview), or (3) not a plausible continuation of the pre-target text, nor compatible with the post-target text (implausible preview). Gaze durations on target words were longer in the initially plausible condition than the identical condition. Overall, the results showed a typical preview benefit, but also implied that readers did not encode the initially plausible preview. Also, a plausibility preview benefit was replicated: gaze durations were longer with implausible previews than the initially plausible ones. Furthermore, late eye movement measures did not reveal differences between the initially plausible and the implausible preview conditions, which argues against the possibility of misreading the plausible preview word as the target word. In sum, these results suggest that a plausible preview word provides benefit in processing the target word as compared to an implausible preview word, and this benefit is only present in early but not late eye movement measures.

  4. Plausibility Judgments in Conceptual Change and Epistemic Cognition

    Science.gov (United States)

    Lombardi, Doug; Nussbaum, E. Michael; Sinatra, Gale M.

    2016-01-01

    Plausibility judgments rarely have been addressed empirically in conceptual change research. Recent research, however, suggests that these judgments may be pivotal to conceptual change about certain topics where a gap exists between what scientists and laypersons find plausible. Based on a philosophical and empirical foundation, this article…

  5. Source Effects and Plausibility Judgments When Reading about Climate Change

    Science.gov (United States)

    Lombardi, Doug; Seyranian, Viviane; Sinatra, Gale M.

    2014-01-01

    Gaps between what scientists and laypeople find plausible may act as a barrier to learning complex and/or controversial socioscientific concepts. For example, individuals may consider scientific explanations that human activities are causing current climate change as implausible. This plausibility judgment may be due-in part-to individuals'…

  6. Unprecedented concentrations of indigenous amino acids in primitive CR meteorites

    Science.gov (United States)

    Ehrenfreund, Pascale; Martins, Zita; Alexander, Conel; Orzechowska, Grazyna; Fogel, Marylin

    CR meteorites are among the most primitive meteorites. We have performed pioneering work determining the compositional characteristics of amino acids in this type of carbonaceous chondrites. We report the first measurements of amino acids in Antarctic CR meteorites, two of which show the highest amino acid concentrations ever found in a chondrite. We have analyzed the amino acid content of the Antarctic CRs EET92042, GRA95229 and GRO95577 using high performance liquid chromatography with UV fluorescence detection (HPLC-FD) and gas chromatography-mass spectrometry (GC-MS). Additionally, compound-specific carbon isotopic measurements for most of the individual amino acids from the EET92042 and GRA95229 meteorites were achieved by gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). Our data show that EET92042 and GRA95229 are the most amino acid-rich chondrites ever analyzed, with total amino acid concentrations of 180 and 249 parts-per-million (ppm), respectively. GRO95577, however, is depleted in amino acids (determined for most amino acids indicate that primitive organic matter was preserved in these meteorites. In addition, the relative abundances of α-AIB and β-alanine amongst Antarctic CR meteorites appear to correspond to the degree of aqueous alteration on their respective parent body. Investigating the abundances and isotopic composition of amino acids in primitive chondrites helps to understand the role of meteorites as a source of extraterrestrial prebiotic organic compounds to the early Earth.

  7. Is formamide a geochemically plausible prebiotic solvent?

    Science.gov (United States)

    Bada, Jeffrey L; Chalmers, John H; Cleaves, H James

    2016-07-27

    From a geochemical perspective, significant amounts of pure formamide (HCONH2) would have likely been rare on the early Earth. There may have been mixed formamide-water solutions, but even in the presence of catalyst, solutions with >20 weight% water in formamide would not have produced significant amounts of prebiotic compounds. It might be feasible to produce relatively pure formamide by a rare occurrence of freezing formamide/water mixtures at temperatures lower than formamide's freezing point (2.55 °C) but greater than the freezing point of water. Because of the high density of formamide ice it would have sunk and accumulated at the bottom of the solution. If the remaining water froze on the surface of this ice, and was then removed by a sublimation-ablation process, a small amount of pure formamide ice might have been produced. In addition a recent report suggested that ∼85 weight% formamide could be prepared by a geochemical type of fractional distillation process, offering another possible route for prebiotic formamide production.

  8. Dynamic Primitives in the Control of Locomotion

    Directory of Open Access Journals (Sweden)

    Neville eHogan

    2013-06-01

    Full Text Available Humans achieve locomotor dexterity that far exceeds the capability of modern robots, yet this is achieved despite slower actuators, imprecise sensors and vastly slower communication. We propose that this spectacular performance arises from encoding motor commands in terms of dynamic primitives. We propose three primitives as a foundation for a comprehensive theoretical framework that can embrace a wide range of upper- and lower-limb behaviors. Building on previous work that suggested discrete and rhythmic movements as elementary dynamic behaviors, we define submovements and oscillations: As discrete movements cannot be combined with sufficient flexibility, we argue that suitably-defined submovements are primitives. As the term rhythmic may be ambiguous, we define oscillations as the corresponding class of primitives. We further propose mechanical impedances as a third class of dynamic primitives, necessary for interaction with the physical environment. Combination of these three classes of primitive requires care. One approach is through a generalized equivalent network: a virtual trajectory composed of simultaneous and/or sequential submovements and/or oscillations that interacts with mechanical impedances to produce observable forces and motions. Reliable experimental identification of these dynamic primitives presents challenges: Identification of mechanical impedances is exquisitely sensitive to assumptions about their dynamic structure; identification of submovements and oscillations is sensitive to their assumed form and to details of the algorithm used to extract them. Some methods to address these challenges are presented. Some implications of this theoretical framework for locomotor rehabilitation are considered.

  9. The efficient global primitive equation climate model SPEEDO V2.0

    NARCIS (Netherlands)

    Severijns, C.A.; Hazeleger, W.

    2010-01-01

    The efficient primitive-equation coupled atmosphere-ocean model SPEEDO V2.0 is presented. The model includes an interactive sea-ice and land component. SPEEDO is a global earth system model of intermediate complexity. It has a horizontal resolution of T30 (triangular truncation at wave number 30) an

  10. The efficient global primitive equation climate model SPEEDO V2.0

    NARCIS (Netherlands)

    Severijns, C.A.; Hazeleger, W.

    2010-01-01

    The efficient primitive-equation coupled atmosphere-ocean model SPEEDO V2.0 is presented. The model includes an interactive sea-ice and land component. SPEEDO is a global earth system model of intermediate complexity. It has a horizontal resolution of T30 (triangular truncation at wave number 30) an

  11. Global Existence and Regularity for the 3D Stochastic Primitive Equations of the Ocean and Atmosphere with Multiplicative White Noise

    OpenAIRE

    Debussche, Arnaud; Glatt-Holtz, Nathan; Temam, Roger; ZIANE, Mohammed

    2011-01-01

    The Primitive Equations are a basic model in the study of large scale Oceanic and Atmospheric dynamics. These systems form the analytical core of the most advanced General Circulation Models. For this reason and due to their challenging nonlinear and anisotropic structure the Primitive Equations have recently received considerable attention from the mathematical community. In view of the complex multi-scale nature of the earth's climate system, many uncertainties appear that should be account...

  12. Plausible values: how to deal with their limitations.

    Science.gov (United States)

    Monseur, Christian; Adams, Raymond

    2009-01-01

    Rasch modeling and plausible values methodology were used to scale and report the results of the Organization for Economic Cooperation and Development's Programme for International Student Achievement (PISA). This article will describe the scaling approach adopted in PISA. In particular it will focus on the use of plausible values, a multiple imputation approach that is now commonly used in large-scale assessment. As with all imputation models the plausible values must be generated using models that are consistent with those used in subsequent data analysis. In the case of PISA the plausible value generation assumes a flat linear regression with all students' background variables collected through the international student questionnaire included as regressors. Further, like most linear models, homoscedasticity and normality of the conditional variance are assumed. This article will explore some of the implications of this approach. First, we will discuss the conditions under which the secondary analyses on variables not included in the model for generating the plausible values might be biased. Secondly, as plausible values were not drawn from a multi-level model, the article will explore the adequacy of the PISA procedures for estimating variance components when the data have a hierarchical structure.

  13. A Biomass-based Model to Estimate the Plausibility of Exoplanet Biosignature Gases

    CERN Document Server

    Seager, S; Hu, R

    2013-01-01

    Biosignature gas detection is one of the ultimate future goals for exoplanet atmosphere studies. We have created a framework for linking biosignature gas detectability to biomass estimates, including atmospheric photochemistry and biological thermodynamics. The new framework is intended to liberate predictive atmosphere models from requiring fixed, Earth-like biosignature gas source fluxes. New biosignature gases can be considered with a check that the biomass estimate is physically plausible. We have validated the models on terrestrial production of NO, H2S, CH4, CH3Cl, and DMS. We have applied the models to propose NH3 as a biosignature gas on a "cold Haber World," a planet with a N2-H2 atmosphere, and to demonstrate why gases such as CH3Cl must have too large of a biomass to be a plausible biosignature gas on planets with Earth or early-Earth-like atmospheres orbiting a Sun-like star. To construct the biomass models, we developed a functional classification of biosignature gases, and found that gases (such...

  14. Discovery of Intrinsic Primitives on Triangle Meshes

    KAUST Repository

    Solomon, Justin

    2011-04-01

    The discovery of meaningful parts of a shape is required for many geometry processing applications, such as parameterization, shape correspondence, and animation. It is natural to consider primitives such as spheres, cylinders and cones as the building blocks of shapes, and thus to discover parts by fitting such primitives to a given surface. This approach, however, will break down if primitive parts have undergone almost-isometric deformations, as is the case, for example, for articulated human models. We suggest that parts can be discovered instead by finding intrinsic primitives, which we define as parts that posses an approximate intrinsic symmetry. We employ the recently-developed method of computing discrete approximate Killing vector fields (AKVFs) to discover intrinsic primitives by investigating the relationship between the AKVFs of a composite object and the AKVFs of its parts. We show how to leverage this relationship with a standard clustering method to extract k intrinsic primitives and remaining asymmetric parts of a shape for a given k. We demonstrate the value of this approach for identifying the prominent symmetry generators of the parts of a given shape. Additionally, we show how our method can be modified slightly to segment an entire surface without marking asymmetric connecting regions and compare this approach to state-of-the-art methods using the Princeton Segmentation Benchmark. © 2011 The Author(s).

  15. Motion Primitives and Probabilistic Edit Distance for Action Recognition

    DEFF Research Database (Denmark)

    Fihl, Preben; Holte, Michael Boelstoft; Moeslund, Thomas B.

    2009-01-01

    the actions as a sequence of temporal isolated instances, denoted primitives. These primitives are each defined by four features extracted from motion images. The primitives are recognized in each frame based on a trained classifier resulting in a sequence of primitives. From this sequence we recognize...

  16. Some Remarks on the Model Theory of Epistemic Plausibility Models

    CERN Document Server

    Demey, Lorenz

    2010-01-01

    Classical logics of knowledge and belief are usually interpreted on Kripke models, for which a mathematically well-developed model theory is available. However, such models are inadequate to capture dynamic phenomena. Therefore, epistemic plausibility models have been introduced. Because these are much richer structures than Kripke models, they do not straightforwardly inherit the model-theoretical results of modal logic. Therefore, while epistemic plausibility structures are well-suited for modeling purposes, an extensive investigation of their model theory has been lacking so far. The aim of the present paper is to fill exactly this gap, by initiating a systematic exploration of the model theory of epistemic plausibility models. Like in 'ordinary' modal logic, the focus will be on the notion of bisimulation. We define various notions of bisimulations (parametrized by a language L) and show that L-bisimilarity implies L-equivalence. We prove a Hennesy-Milner type result, and also two undefinability results. ...

  17. The Plausibility of a String Quartet Performance in Virtual Reality.

    Science.gov (United States)

    Bergstrom, Ilias; Azevedo, Sergio; Papiotis, Panos; Saldanha, Nuno; Slater, Mel

    2017-04-01

    We describe an experiment that explores the contribution of auditory and other features to the illusion of plausibility in a virtual environment that depicts the performance of a string quartet. 'Plausibility' refers to the component of presence that is the illusion that the perceived events in the virtual environment are really happening. The features studied were: Gaze (the musicians ignored the participant, the musicians sometimes looked towards and followed the participant's movements), Sound Spatialization (Mono, Stereo, Spatial), Auralization (no sound reflections, reflections corresponding to a room larger than the one perceived, reflections that exactly matched the virtual room), and Environment (no sound from outside of the room, birdsong and wind corresponding to the outside scene). We adopted the methodology based on color matching theory, where 20 participants were first able to assess their feeling of plausibility in the environment with each of the four features at their highest setting. Then five times participants started from a low setting on all features and were able to make transitions from one system configuration to another until they matched their original feeling of plausibility. From these transitions a Markov transition matrix was constructed, and also probabilities of a match conditional on feature configuration. The results show that Environment and Gaze were individually the most important factors influencing the level of plausibility. The highest probability transitions were to improve Environment and Gaze, and then Auralization and Spatialization. We present this work as both a contribution to the methodology of assessing presence without questionnaires, and showing how various aspects of a musical performance can influence plausibility.

  18. Primitive Near-rings-Some Structure Theorems

    Institute of Scientific and Technical Information of China (English)

    Gerhard Wendt

    2007-01-01

    We show that any zero symmetric 1-primitive near-ring with descending chain condition on left ideals can be described as a centralizer near-ring in which the multipli-cation is not the function composition but sandwich multiplication.This result follows from a more general structure theorem on 1-primitive near-rings with multiplicative right identity,not necessarily having a chain condition on left ideals.We then use our results to investigate more closely the multiplicative semigroup of a 1-primitive near-ring.In par-ticular,we show that the set of regular elements forms a right ideal of the multiplicative semigroup of the near-ring.

  19. The physics and metaphysics of primitive stuff

    CERN Document Server

    Esfeld, Michael; Lam, Vincent; Hubert, Mario

    2014-01-01

    The paper sets out a primitive ontology of the natural world in terms of primitive stuff, that is, stuff that has as such no physical properties at all, but that is not a bare substratum either, being individuated by metrical relations. We focus on quantum physics and employ identity-based Bohmian mechanics to illustrate this view, but point out that it applies all over physics. Properties then enter into the picture exclusively through the role that they play for the dynamics of the primitive stuff. We show that such properties can be local (classical mechanics), as well as holistic (quantum mechanics), and discuss two metaphysical options to conceive them, namely Humeanism and modal realism in the guise of dispositionalism.

  20. Relation of Origins of Primitive Chaos

    CERN Document Server

    Ogasawara, Yoshihito

    2014-01-01

    A new concept, primitive chaos, was proposed, as a concept closely related to the fundamental problems of sciences themselves such as determinism, causality, free will, predictability, and time asymmetry [{\\em J. Phys. Soc. Jpn.} {\\bf 2014}, {\\em 83}, 1401]. This concept is literally a primitive chaos in such a sense that it leads to the characteristic properties of the conventional chaos under natural conditions. Then, two contrast concepts, nondegenerate Peano continuum and Cantor set, are known as the origins of the primitive chaos. In this study, the relation of these origins is investigated with the aid of a mathematical method, topology. Then, we can see the emergence of interesting concepts such as the relation of whole and part, and coarse graining, which imply the essence of our intrinsic recognition for phenomena.

  1. Primitive neuroectodermal tumor of the heart.

    Science.gov (United States)

    Nwaejike, Nnamdi; Rassl, Doris; Ford, Hugo; Large, Stephen R

    2012-02-01

    We present a case of primitive neuroectodermal tumor of the left atrium with involvement of the coronary sinus. The initial presentation was of cardiac tamponade resulting from the size of the tumor. There was no evidence of tumor elsewhere, and after complete resection and without adjuvant chemotherapy the patient is well at 2-year follow-up. There has been no evidence of tumor recurrence. This is a rare reported case of resection of a cardiac primitive neuroectodermal tumor without adjuvant chemotherapy. Other cases in the literature have been treated by orthoptic transplantation and resection with chemotherapy.

  2. Primary primitive neuroectodermal tumor of spinal cord

    Directory of Open Access Journals (Sweden)

    Ashutosh Das Sharma

    2016-01-01

    Full Text Available Primarily spinal primitive neuroectodermal tumors are rare neoplasm. A 28-year-old female presented with complaints of pain in lower back, radiating to both lower limbs. Magnetic resonance imaging scan of the lumbosacral spine showed an intradural extramedullary space-occupying lesion. The patient underwent L2–L5 laminectomy with excision of the lesion. Histopathology and immunohistochemistry reports confirmed the diagnosis of primitive neuroectodermal tumor while a thorough metastatic workup ruled out secondary to the spinal cord. The patient developed recurrence at local site within a month after surgery, even before the adjuvant treatment could be started. She is being treated with chemotherapy (human resources protocol.

  3. [Primitive neuroectodermal tumor of the vagus nerve].

    Science.gov (United States)

    Pegbessou, E; Diom, E S; Ndiaye, M; Dieng, P A; Nao, E E M; Thiam, A; Diouf, M S; Boube, D; Ndiaye, C; Kossinda, F; Tall, A; Diallo, B K; Ndiaye, I C; Diouf, R; Diop, E M

    2013-12-01

    Primitive neuroectodermal tumors are a rare type of malignant neuroectodermal tumor that is very aggressive. Cervicofacial location is rare, even exceptional. We report a case of a 4-month-old male infant, referred from the pediatric clinic for severe supralaryngeal dyspnea, a firm mass under the left mandibular angle, mobile and extended to the parotid area, painful, with a curve of the left side wall of the oropharynx. Cervical computed tomodensitometry showed a well-limited mass in the carotid area, enhanced by the contrast product. A vascularized mass, which had developed at the expense of the vagus nerve, was removed surgically. Histology found a primitive neuroectodermal tumor.

  4. Primitive Form of Bony Fish Unveiled

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    @@ With over 50,000 species,Osteichthyans, or bony fish, accounts for 98% of the present-day vertebrates. Bony fish falls into two groups: actinopterygians, meaning ray-finned bony fish, and sarcopterygians,meaning lobe-finned bony fish. The huge morphotype difference of the two catagories cast doubts on research into the origin and evolution of bony fish. The recent discovery of a primitive fish species by CAS researchers and their overseas colleagues provides a missing link between the two lineages, unveiling unique features for understanding primitive bony vertebrates.

  5. Classification using sparse representations: a biologically plausible approach.

    Science.gov (United States)

    Spratling, M W

    2014-02-01

    Representing signals as linear combinations of basis vectors sparsely selected from an overcomplete dictionary has proven to be advantageous for many applications in pattern recognition, machine learning, signal processing, and computer vision. While this approach was originally inspired by insights into cortical information processing, biologically plausible approaches have been limited to exploring the functionality of early sensory processing in the brain, while more practical applications have employed non-biologically plausible sparse coding algorithms. Here, a biologically plausible algorithm is proposed that can be applied to practical problems. This algorithm is evaluated using standard benchmark tasks in the domain of pattern classification, and its performance is compared to a wide range of alternative algorithms that are widely used in signal and image processing. The results show that for the classification tasks performed here, the proposed method is competitive with the best of the alternative algorithms that have been evaluated. This demonstrates that classification using sparse representations can be performed in a neurally plausible manner, and hence, that this mechanism of classification might be exploited by the brain.

  6. Transgression, Nostalgia, Order: Representation of the Primitive in Émile Zola's La Terre and Knut Hamsun's Markens grøde

    Directory of Open Access Journals (Sweden)

    Riikka Rossi

    2012-03-01

    Full Text Available This article examines the representation of the primitive in two peasant novels, Émile Zola's La Terre (1887, trans. as The Earth and Knut Hamsun's Markens grøde (1917, trans. as Growth of the Soil. The concept of the primitive crosses a wide range of issues that were central to naturalist and decadent literature at the turn of the twentieth century, from unconscious instincts to the fascination with exotic cultures. It thus offers a fruitful medium for the comparative reading of French and Nordic fiction of the era. I especially focus on analysing the diverse, representative practices of Zola's and Hamsun's works, which betray stylistic differences in their portrayal of the primitive. I suggest that by describing the primitive as a vital, transgressive force that even turns against itself - against nature - Zola's La Terre creates a decadent version of the primitive, which, instead of a "serious", naturalistic portrayal of everyday life, is drawn to the brutal, instinctive primitive and uses the primitive to create vital forces of transgression. Hamsun's neo-naturalist novel, in turn, reconfigures the naturalist themes in a new form and envisions a fusion of the Darwinian, naturalistic primitive and the Romantic cult of innocent primordiality, suggesting the primitive lifestyle as a nostalgic return to a pre-modern lifestyle and a turn away from the degeneration of modernity.

  7. The Growth of a Primitive Penumbra

    Science.gov (United States)

    Sreejith, P.; Tritschler, A.; Sankarasubramanian, K.

    We report on the penumbral formation in active region NOAA 10837. The penumbra observed on continuum intensity images grew from a quiet-Sun area to a primitive penumbra and then to a fully developed penumbra over about 5 h. The growth indicates nonlinear development with time.

  8. Cutaneous metastasis of primitive neuroectodermal lung tumor.

    Science.gov (United States)

    Garcia Romero, Diana; Hilara Sanchez, Yolanda; Perez Alvarez, Javier; Ramirez Garcia, Jose Ramon; De Pable Martin, Maria Pilar

    2013-06-15

    Primary sarcomas of the chest are rare. Although primitive neuroectodermal tumor (PNET) usually develops in the chest wall, it has been described as a primary pulmonary tumor. We present an unusual case of PNET arising in the lung of an 89-year-old man.

  9. Primitive neuroectodermal tumor of the kidney

    Directory of Open Access Journals (Sweden)

    Aatif Rashid

    2012-01-01

    Full Text Available Primitive neuroectodermal tumor of the kidney is a rare entity. Only a few cases have been reported in the literature and they revealed a variable presentation and an aggressive behavior. Most commonly it is seen in the relatively young population. The diagnosis is usually made at histopathology.

  10. Melville and the Tradition of Primitive Utopia.

    Science.gov (United States)

    Beauchamp, Gorman

    1981-01-01

    Discusses the relationships among the myth of the Golden Age, the concept of the Noble Savage, and the dream of Utopia. Uses Lewis Mumford's division of utopias into two basic types, i.e., reconstruction and escape utopias, to examine Herman Melville's "Typee" as an example of the primitive escapist utopia. (Editor/DMM)

  11. Evolution of Computational Toxicology-from Primitive ...

    Science.gov (United States)

    Presentation at the Health Canada seminar in Ottawa, ON, Canada on Nov. 15. 2016 Presentation at the Health Canada seminar in Ottawa, ON, Canada on Nov. 15. 2016 on the Evolution of Computational Toxicology-from Primitive Beginnings to Sophisticated Application

  12. Convolutions with the Continuous Primitive Integral

    Directory of Open Access Journals (Sweden)

    Erik Talvila

    2009-01-01

    I⊂ℝ. When g∈L1, the estimate is ‖f∗g‖≤‖f‖‖g‖1. There are results on differentiation and integration of convolutions. A type of Fubini theorem is proved for the continuous primitive integral.

  13. Distribution of Primitive λ-Roots of Composite Moduli Ⅱ

    Institute of Scientific and Technical Information of China (English)

    Zhiyong ZHENG; Todd COCHRANE

    2006-01-01

    We improve estimates for the distribution of primitive λ-roots of a composite modulus q yielding an asymptotic formula for the number of primitive λ-roots in any interval Ⅰ of length |I| (>>) q1/2+∈. Similar results are obtained for the distribution of ordered pairs (x, x-1) with x a primitive λ-root, and for the number of primitive λ-roots satisfying inequalities such as |x -x-1| ≤ B.

  14. Families of Plausible Solutions to the Puzzle of Boyajian's Star

    CERN Document Server

    Wright, Jason T

    2016-01-01

    Good explanations for the unusual light curve of Boyajian's Star have been hard to find. Recent results by Montet & Simon lend strength and plausibility to the conclusion of Schaefer that in addition to short-term dimmings, the star also experiences large, secular decreases in brightness on decadal timescales. This, combined with a lack of long-wavelength excess in the star's spectral energy distribution, strongly constrains scenarios involving circumstellar material, including hypotheses invoking a spherical cloud of artifacts. We show that the timings of the deepest dimmings appear consistent with being randomly distributed, and that the star's reddening and narrow sodium absorption is consistent with the total, long-term dimming observed. Following Montet & Simon's encouragement to generate alternative hypotheses, we attempt to circumscribe the space of possible explanations with a range of plausibilities, including: a cloud in the outer solar system, structure in the ISM, natural and artificial ma...

  15. Representations of physical plausibility revealed by event-related potentials.

    Science.gov (United States)

    Roser, Matthew E; Fugelsang, Jonathan A; Handy, Todd C; Dunbar, Kevin N; Gazzaniga, Michael S

    2009-08-05

    Maintaining an accurate mental representation of the current environment is crucial to detecting change in that environment and ensuring behavioral coherence. Past experience with interactions between objects, such as collisions, has been shown to influence the perception of object interactions. To assess whether mental representations of object interactions derived from experience influence the maintenance of a mental model of the current stimulus environment, we presented physically plausible and implausible collision events while recording brain electrical activity. The parietal P300 response to 'oddball' events was found to be modulated by the physical plausibility of the stimuli, suggesting that past experience of object interactions can influence working memory processes involved in monitoring ongoing changes to the environment.

  16. Isotopic evidence for internal oxidation of the Earth's mantle during accretion

    Science.gov (United States)

    Williams, Helen M.; Wood, Bernard J.; Wade, Jon; Frost, Daniel J.; Tuff, James

    2012-03-01

    The Earth's mantle is currently oxidised and out of chemical equilibrium with the core. The reasons for this and for the relatively oxidised state of Earth's mantle relative to the mantles of other terrestrial planets are unclear. It has been proposed that the oxidised nature and high ferric iron (Fe3 +) content of Earth's mantle was produced internally by disproportionation of ferrous iron (Fe2 +) into Fe3 + and metallic iron by perovskite crystallisation during accretion. Here we show that there is substantial Fe isotope fractionation between experimentally equilibrated metal and Fe3 +-bearing perovskite (≥ 0.45‰/amu), which can account for the heavy Fe isotope compositions of terrestrial basalts relative to equivalent samples derived from Mars and Vesta as the latter bodies are too small to stabilise significant perovskite. Mass balance calculations indicate that all of the mantle's Fe3 + could readily have been generated from a single disproportionation event, consistent with dissolution of perovskite in the lower mantle during a process such as the Moon-forming giant impact. The similar Fe isotope compositions of primitive terrestrial and low-titanium lunar basalts is consistent with models of equilibration between the mantles of the Earth and Moon in the aftermath of the giant impact and suggests that the heavy Fe isotope composition of the Earth's mantle was established prior to, or during the giant impact. The oxidation state and ferric iron content of the Earth's mantle was therefore plausibly set by the end of accretion, and may be decoupled from later volatile additions and the rise of oxygen in the Earth's atmosphere at 2.45 Ga.

  17. Probabilistic reasoning in intelligent systems networks of plausible inference

    CERN Document Server

    Pearl, Judea

    1988-01-01

    Probabilistic Reasoning in Intelligent Systems is a complete and accessible account of the theoretical foundations and computational methods that underlie plausible reasoning under uncertainty. The author provides a coherent explication of probability as a language for reasoning with partial belief and offers a unifying perspective on other AI approaches to uncertainty, such as the Dempster-Shafer formalism, truth maintenance systems, and nonmonotonic logic. The author distinguishes syntactic and semantic approaches to uncertainty--and offers techniques, based on belief networks, that provid

  18. Complex Learning in Bio-plausible Memristive Networks

    OpenAIRE

    Deng, Lei; Li, Guoqi; Deng, Ning; Dong WANG; Zhang, Ziyang; He, Wei; Li, Huanglong; Pei, Jing; Shi, Luping

    2015-01-01

    The emerging memristor-based neuromorphic engineering promises an efficient computing paradigm. However, the lack of both internal dynamics in the previous feedforward memristive networks and efficient learning algorithms in recurrent networks, fundamentally limits the learning ability of existing systems. In this work, we propose a framework to support complex learning functions by introducing dedicated learning algorithms to a bio-plausible recurrent memristive network with internal dynamic...

  19. The Exponent Set of Central Symmetric Primitive Matrices

    Institute of Scientific and Technical Information of China (English)

    陈佘喜; 胡亚辉

    2004-01-01

    This paper first establishes a distance inequality of the associated diagraph of a central symmetric primitive matrix, then characters the exponent set of central symmetric primitive matrices, and proves that the exponent set of central symmetric primitive matrices of order n is {1, 2,… ,n-1}. There is no gap in it.

  20. Character sums for primitive root densities

    CERN Document Server

    Lenstra, H W; Stevenhagen, P

    2011-01-01

    It follows from the work of Artin and Hooley that, under assumption of the generalized Riemann hypothesis, the density of the set of primes $q$ for which a given non-zero rational number $r$ is a primitive root modulo $q$ can be written as an infinite product $\\prod_p \\delta_p$ of local factors $\\delta_p$ reflecting the degree of the splitting field of $X^p-r$ at the primes $p$, multiplied by a somewhat complicated factor that corrects for the `entanglement' of these splitting fields. We show how the correction factors arising in Artin's original primitive root problem and some of its generalizations can be interpreted as character sums describing the nature of the entanglement. The resulting description in terms of local contributions is so transparent that it greatly facilitates explicit computations, and naturally leads to non-vanishing criteria for the correction factors.

  1. Self-assembly of phosphate amphiphiles in mixtures of prebiotically plausible surfactants.

    Science.gov (United States)

    Albertsen, A N; Duffy, C D; Sutherland, J D; Monnard, P-A

    2014-06-01

    The spontaneous formation of closed bilayer structures from prebiotically plausible amphiphiles is an essential requirement for the emergence of early cells on prebiotic Earth. The sources of amphiphiles could have been both endo- and exogenous (accretion of meteorite carbonaceous material or interstellar dust particles). Among all prebiotic possible amphiphile candidates, those containing phosphate are the least investigated species because their self-assembly occurs in a seemingly too narrow range of conditions. The self-assembly of simple phosphate amphiphiles should, however, be of great interest, as contemporary membranes predominantly contain phospholipids. In contrast to common expectations, we show that these amphiphiles can be easily synthesized under prebiotically plausible environmental conditions and can efficiently form bilayer structures in the presence of various co-surfactants across a large range of pH values. Vesiculation was even observed in crude reaction mixtures that contained 1-decanol as the amphiphile precursor. The two best co-surfactants promoted vesicle formation over the entire pH range in aqueous solutions. Expanding the pH range where bilayer membranes self-assemble and remain intact is a prerequisite for the emergence of early cell-like compartments and their preservation under fluctuating environmental conditions. These mixed bilayers also retained small charged solutes, such as dyes. These results demonstrate that alkyl phosphate amphiphiles might have played a significant role as early compartment building blocks.

  2. Deriving motor primitives through action segmentation.

    Science.gov (United States)

    Hemeren, Paul E; Thill, Serge

    2010-01-01

    The purpose of the present experiment is to further understand the effect of levels of processing (top-down vs. bottom-up) on the perception of movement kinematics and primitives for grasping actions in order to gain insight into possible primitives used by the mirror system. In the present study, we investigated the potential of identifying such primitives using an action segmentation task. Specifically, we investigated whether or not segmentation was driven primarily by the kinematics of the action, as opposed to high-level top-down information about the action and the object used in the action. Participants in the experiment were shown 12 point-light movies of object-centered hand/arm actions that were either presented in their canonical orientation together with the object in question (top-down condition) or upside down (inverted) without information about the object (bottom-up condition). The results show that (1) despite impaired high-level action recognition for the inverted actions participants were able to reliably segment the actions according to lower-level kinematic variables, (2) segmentation behavior in both groups was significantly related to the kinematic variables of change in direction, velocity, and acceleration of the wrist (thumb and finger tips) for most of the included actions. This indicates that top-down activation of an action representation leads to similar segmentation behavior for hand/arm actions compared to bottom-up, or local, visual processing when performing a fairly unconstrained segmentation task. Motor primitives as parts of more complex actions may therefore be reliably derived through visual segmentation based on movement kinematics.

  3. Primary primitive neuroectodermal tumor of the orbit

    Directory of Open Access Journals (Sweden)

    Das Dipankar

    2009-01-01

    Full Text Available Primitive neuroectodermal tumor (PNET is a small round cell malignant tumor of neuroectodermal origin. Most of the PNETs occur in the central nervous system (CNS. PNETs recognized outside of CNS are diagnosed as peripheral PNET (pPNET. This tumor which expresses MIC-2 gene (CD99 seems to be least aggressive after complete tumor resection. We describe a rare case of PNET in a young girl.

  4. Deriving Motor Primitives through Action Segmentation

    Directory of Open Access Journals (Sweden)

    Paul E. Hemeren

    2011-01-01

    Full Text Available The purpose of the present experiment is to further understand the effect of levels of processing (top-down vs. bottom-up on the perception of movement kinematics and primitives for grasping actions in order to gain insight into possible primitives used by the mirror system. In the present study, we investigated the potential of identifying such primitives using an action segmentation task. Specifically, we investigated whether or not segmentation was driven primarily by the kinematics of the action, as opposed to high-level top-down information about the action and the object used in the action. Participants in the experiment were shown twelve point-light movies of object-centered hand/arm actions that were either presented in their canonical orientation together with the object in question or upside-down (inverted without information about the object. The results show that (1 despite impaired high-level action recognition for the inverted actions participants were able to reliably segment the actions according to lower-level kinematic variables, (2 segmentation behavior in both groups was significantly related to the kinematic variables of change in direction, velocity and acceleration of the wrist (thumb and finger tips for most of the included actions. This indicates that top-down activation of an action representation leads to similar segmentation behavior for hand/arm actions compared to bottom-up, or local, visual processing when performing a fairly unconstrained segmentation task. Motor primitives as parts of more complex actions may therefore be reliably derived through visual segmentation based on movement kinematics.

  5. PRIMITIVE NEUROECTODERMAL TUMOR OF URINARY BLADDER

    Directory of Open Access Journals (Sweden)

    Jagadeeshwar

    2014-12-01

    Full Text Available PNET of the urinary bladder is extremely rare. Only 12 cases are reported till now in the world. Primitive Neuro Ectodermal Tumor (PNET is a malignant small round blue cell tumor exhibiting a variable degree of neural differentiation, which arises outside the brain, spinal cord and sympathetic nervous system. (1,2 PNET is a very aggressive tumor with rapid local infiltration combined with widespread metastasis.

  6. Accounting for primitive terms in mathematics

    Directory of Open Access Journals (Sweden)

    D.F.M. Strauss

    2005-07-01

    Full Text Available The philosophical problem of unity and diversity entails a challenge to the rationalist aim to define everything. Definitions of this kind surface in various academic disciplines in formulations like uniqueness, irreducibility, and what has acquired the designation “primitive terms”. Not even the most “exact” disciplines, such as mathematics, can avoid the implications entailed in giving an account of such primitive terms. A mere look at the historical development of mathematics highlights the fact that alternative perspectives prevailed – from the arithmeticism of Pythagoreanism, the eventual geometrisation of mathematics after the discovery of incommensurability up to the revival of arithmeticism in the mathematics of Cauchy, Weierstrass, Dedekind and Cantor (with the later orientation of Frege, who completed the circle by returning to the view that mathematics essentially is geometry. An assessment of logicism and axiomatic formalism is followed by looking at the primitive meaning of wholeness (and the whole-parts relation. With reference to the views of Hilbert, Weyl and Bernays the article concludes by suggesting that in opposition to arithmeticism and geometricism an alternative option ought to be pursued – one in which both the uniqueness and mutual coherence between the aspects of number and space are acknowledged.

  7. Spontaneous formation and base pairing of plausible prebiotic nucleotides in water.

    Science.gov (United States)

    Cafferty, Brian J; Fialho, David M; Khanam, Jaheda; Krishnamurthy, Ramanarayanan; Hud, Nicholas V

    2016-04-25

    The RNA World hypothesis presupposes that abiotic reactions originally produced nucleotides, the monomers of RNA and universal constituents of metabolism. However, compatible prebiotic reactions for the synthesis of complementary (that is, base pairing) nucleotides and mechanisms for their mutual selection within a complex chemical environment have not been reported. Here we show that two plausible prebiotic heterocycles, melamine and barbituric acid, form glycosidic linkages with ribose and ribose-5-phosphate in water to produce nucleosides and nucleotides in good yields. Even without purification, these nucleotides base pair in aqueous solution to create linear supramolecular assemblies containing thousands of ordered nucleotides. Nucleotide anomerization and supramolecular assemblies favour the biologically relevant β-anomer form of these ribonucleotides, revealing abiotic mechanisms by which nucleotide structure and configuration could have been originally favoured. These findings indicate that nucleotide formation and selection may have been robust processes on the prebiotic Earth, if other nucleobases preceded those of extant life.

  8. Plausible scenarios for the radiography profession in Sweden in 2025.

    Science.gov (United States)

    Björkman, B; Fridell, K; Tavakol Olofsson, P

    2017-11-01

    Radiography is a healthcare speciality with many technical challenges. Advances in engineering and information technology applications may continue to drive and be driven by radiographers. The world of diagnostic imaging is changing rapidly and radiographers must be proactive in order to survive. To ensure sustainable development, organisations have to identify future opportunities and threats in a timely manner and incorporate them into their strategic planning. Hence, the aim of this study was to analyse and describe plausible scenarios for the radiography profession in 2025. The study has a qualitative design with an inductive approach based on focus group interviews. The interviews were inspired by the Scenario-Planning method. Of the seven trends identified in a previous study, the radiographers considered two as the most uncertain scenarios that would have the greatest impact on the profession should they occur. These trends, labelled "Access to career advancement" and "A sufficient number of radiographers", were inserted into the scenario cross. The resulting four plausible future scenarios were: The happy radiographer, the specialist radiographer, the dying profession and the assembly line. It is suggested that "The dying profession" scenario could probably be turned in the opposite direction by facilitating career development opportunities for radiographers within the profession. Changing the direction would probably lead to a profession composed of "happy radiographers" who are specialists, proud of their profession and competent to carry out advanced tasks, in contrast to being solely occupied by "the assembly line". Copyright © 2017 The College of Radiographers. Published by Elsevier Ltd. All rights reserved.

  9. Prebiotically plausible mechanisms increase compositional diversity of nucleic acid sequences.

    Science.gov (United States)

    Derr, Julien; Manapat, Michael L; Rajamani, Sudha; Leu, Kevin; Xulvi-Brunet, Ramon; Joseph, Isaac; Nowak, Martin A; Chen, Irene A

    2012-05-01

    During the origin of life, the biological information of nucleic acid polymers must have increased to encode functional molecules (the RNA world). Ribozymes tend to be compositionally unbiased, as is the vast majority of possible sequence space. However, ribonucleotides vary greatly in synthetic yield, reactivity and degradation rate, and their non-enzymatic polymerization results in compositionally biased sequences. While natural selection could lead to complex sequences, molecules with some activity are required to begin this process. Was the emergence of compositionally diverse sequences a matter of chance, or could prebiotically plausible reactions counter chemical biases to increase the probability of finding a ribozyme? Our in silico simulations using a two-letter alphabet show that template-directed ligation and high concatenation rates counter compositional bias and shift the pool toward longer sequences, permitting greater exploration of sequence space and stable folding. We verified experimentally that unbiased DNA sequences are more efficient templates for ligation, thus increasing the compositional diversity of the pool. Our work suggests that prebiotically plausible chemical mechanisms of nucleic acid polymerization and ligation could predispose toward a diverse pool of longer, potentially structured molecules. Such mechanisms could have set the stage for the appearance of functional activity very early in the emergence of life.

  10. Dimensional analysis using toric ideals: primitive invariants.

    Science.gov (United States)

    Atherton, Mark A; Bates, Ronald A; Wynn, Henry P

    2014-01-01

    Classical dimensional analysis in its original form starts by expressing the units for derived quantities, such as force, in terms of power products of basic units [Formula: see text] etc. This suggests the use of toric ideal theory from algebraic geometry. Within this the Graver basis provides a unique primitive basis in a well-defined sense, which typically has more terms than the standard Buckingham approach. Some textbook examples are revisited and the full set of primitive invariants found. First, a worked example based on convection is introduced to recall the Buckingham method, but using computer algebra to obtain an integer [Formula: see text] matrix from the initial integer [Formula: see text] matrix holding the exponents for the derived quantities. The [Formula: see text] matrix defines the dimensionless variables. But, rather than this integer linear algebra approach it is shown how, by staying with the power product representation, the full set of invariants (dimensionless groups) is obtained directly from the toric ideal defined by [Formula: see text]. One candidate for the set of invariants is a simple basis of the toric ideal. This, although larger than the rank of [Formula: see text], is typically not unique. However, the alternative Graver basis is unique and defines a maximal set of invariants, which are primitive in a simple sense. In addition to the running example four examples are taken from: a windmill, convection, electrodynamics and the hydrogen atom. The method reveals some named invariants. A selection of computer algebra packages is used to show the considerable ease with which both a simple basis and a Graver basis can be found.

  11. Dimensional analysis using toric ideals: primitive invariants.

    Directory of Open Access Journals (Sweden)

    Mark A Atherton

    Full Text Available Classical dimensional analysis in its original form starts by expressing the units for derived quantities, such as force, in terms of power products of basic units [Formula: see text] etc. This suggests the use of toric ideal theory from algebraic geometry. Within this the Graver basis provides a unique primitive basis in a well-defined sense, which typically has more terms than the standard Buckingham approach. Some textbook examples are revisited and the full set of primitive invariants found. First, a worked example based on convection is introduced to recall the Buckingham method, but using computer algebra to obtain an integer [Formula: see text] matrix from the initial integer [Formula: see text] matrix holding the exponents for the derived quantities. The [Formula: see text] matrix defines the dimensionless variables. But, rather than this integer linear algebra approach it is shown how, by staying with the power product representation, the full set of invariants (dimensionless groups is obtained directly from the toric ideal defined by [Formula: see text]. One candidate for the set of invariants is a simple basis of the toric ideal. This, although larger than the rank of [Formula: see text], is typically not unique. However, the alternative Graver basis is unique and defines a maximal set of invariants, which are primitive in a simple sense. In addition to the running example four examples are taken from: a windmill, convection, electrodynamics and the hydrogen atom. The method reveals some named invariants. A selection of computer algebra packages is used to show the considerable ease with which both a simple basis and a Graver basis can be found.

  12. Primitive Ontology and the Classical World

    Science.gov (United States)

    Allori, Valia

    In this chapter, I present the common structure of quantum theories with a primitive ontology (PO), and discuss in what sense the classical world emerges from quantum theories as understood in this framework. In addition, I argue that the PO approach is better at analyzing the classical limit than the rival wave function ontology approach or any other approach in which the classical world is non-reductively "emergent:" even if the classical limit within this framework needs to be fully developed, the difficulties are technical rather than conceptual, while this is not true for the alternatives.

  13. CSC Trigger Primitive Rates in ORCA

    CERN Document Server

    Cousins, Robert; Valuev, S

    2002-01-01

    Recent work in ORCA has prompted us to make a new estimate of the background rates in the Level-1 CSC Trigger Primitives. We report our findings for SimHit, digi, and LCT rates, as well as the input LCT rates in the Muon Port Cards. We compare our estimates with two earlier results (Level-1 Trigger TDR, and ``Background LCT Rates by CSC Type Using the Forward Muon Trigger Simulation in CMS100'' by Breedon, Fisyak, Ko and Rowe), and observe some differences attributed to geometry changes, improved shielding, and improved CSC and Level-1 Trigger simulation. % and larger statistics in the present study.

  14. Cryptographic primitives based on cellular transformations

    Directory of Open Access Journals (Sweden)

    B.V. Izotov

    2003-11-01

    Full Text Available Design of cryptographic primitives based on the concept of cellular automata (CA is likely to be a promising trend in cryptography. In this paper, the improved method performing data transformations by using invertible cyclic CAs (CCA is considered. Besides, the cellular operations (CO as a novel CAs application in the block ciphers are introduced. Proposed CCAs and COs, integrated under the name of cellular transformations (CT, suit well to be used in cryptographic algorithms oriented to fast software and cheap hardware implementation.

  15. Computational Study of a Primitive Life Model

    Science.gov (United States)

    Andrecut, Mircea

    We present a computational study of a primitive life model. The calculation involves a discrete treatment of a partial differential equation and some details of that problems are explained. We show that the investigated model is equivalent to a diffusively coupled logistic lattice. The bifurcation diagrams were calculated for different values of the control parameters. The obtained diagrams have shown that the time dependence of the population of the investigated model exhibits transitions between ordered and chaotic behavior. We have investigated also the patterns formation in this system.

  16. Quantum information: primitive notions and quantum correlations

    CERN Document Server

    Scarani, Valerio

    2009-01-01

    This series of introductory lectures consists of two parts. In the first part, I rapidly review the basic notions of quantum physics and many primitives of quantum information (i.e. notions that one must be somehow familiar with in the field, like cloning, teleportation, state estimation...). The second part is devoted to a detailed introduction to the topic of quantum correlations, covering the evidence for failure of alternative theories, some aspects of the formalism of no-signaling probability distributions and some hints towards some current research topics in the field.

  17. Neural networks, nativism, and the plausibility of constructivism.

    Science.gov (United States)

    Quartz, S R

    1993-09-01

    Recent interest in PDP (parallel distributed processing) models is due in part to the widely held belief that they challenge many of the assumptions of classical cognitive science. In the domain of language acquisition, for example, there has been much interest in the claim that PDP models might undermine nativism. Related arguments based on PDP learning have also been given against Fodor's anti-constructivist position--a position that has contributed to the widespread dismissal of constructivism. A limitation of many of the claims regarding PDP learning, however, is that the principles underlying this learning have not been rigorously characterized. In this paper, I examine PDP models from within the framework of Valiant's PAC (probably approximately correct) model of learning, now the dominant model in machine learning, and which applies naturally to neural network learning. From this perspective, I evaluate the implications of PDP models for nativism and Fodor's influential anti-constructivist position. In particular, I demonstrate that, contrary to a number of claims, PDP models are nativist in a robust sense. I also demonstrate that PDP models actually serve as a good illustration of Fodor's anti-constructivist position. While these results may at first suggest that neural network models in general are incapable of the sort of concept acquisition that is required to refute Fodor's anti-constructivist position, I suggest that there is an alternative form of neural network learning that demonstrates the plausibility of constructivism. This alternative form of learning is a natural interpretation of the constructivist position in terms of neural network learning, as it employs learning algorithms that incorporate the addition of structure in addition to weight modification schemes. By demonstrating that there is a natural and plausible interpretation of constructivism in terms of neural network learning, the position that nativism is the only plausible model of

  18. THE SECOND EXPONENT SET OF PRIMITIVE DIGRAPHS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Let D = (V,E) be a primitive digraph. The exponent of D, denoted by γ(D), is the least integer k such that for any u, v ∈ V there is a directed walk of length k from u to v. The local exponent of D at a vertex u ∈ V, denoted by expD (u), is the least integer k such that there is a directed walk of length k from u to v for each v ∈ V. Let V = {1,2,... ,n}. Following [1], the vertices of V are ordered so that exPD (1) ≤expD (2)≤…≤expD (n) =γ(D). Let En(i) := {expD (i) | D ∈ PDn}, where PDn is the set of all primitive digraphs of order n. It is known that En(n) = {γ(D) | D ∈ PDn} has been completely settled by [7]. In 1998, En(1)was characterized by [5]. In this paper, the authors describe En(2) for all n≥2.

  19. Primary primitive neuroectodermal tumor of the cervix

    Directory of Open Access Journals (Sweden)

    Li B

    2013-06-01

    Full Text Available Bo Li,1 Ling Ouyang,1 Xue Han,1 Yang Zhou,1 Xin Tong,1 Shulang Zhang,1 Qingfu Zhang21Department of Obstetrics and Gynecology, Shengjing Hospital of China Medical University, 2Department of Pathology, the First Affiliated Hospital and College of Basic Medical Sciences, China Medical University, Shenyang, People’s Republic of ChinaAbstract: Primary primitive neuroectodermal tumors (PNETs are rare and high-grade malignant tumors that mostly occur in children and young adults. The most common sites are the trunk, limbs, and retroperitoneum. Herein, we present a case of a PNET involving the cervix uteri in a 27-year-old woman. The lesion showed characteristic histologic features of a PNET and was positive for the immunohistochemical markers cluster of differentiation (CD 99, vimentin, neuron-specific enolase, neural cell adhesion molecule 1 (CD56, and CD117 (c-kit, further defining the tumor while helping to confirm PNET. The clinical Stage IIIB tumor was treated with chemotherapy and radiotherapy.Keywords: primitive neuroectodermal tumor, PNET, cervical neoplasm, immunohistochemistry

  20. Peripheral primitive neuroectodermal tumor in masseter muscle.

    Science.gov (United States)

    Yazc, Haşmet; Yiğit, Barş; Doğan, Sedat; Sunter, Ahmet Volkan; Behzatoğlu, Kemal

    2013-05-01

    Primitive neuroectodermal tumor is a member of malignant small round cell tumors. These tumors especially originate from the central and autonomous nervous system. However, these tumors may be originated from peripheral tissues and are called peripheral primitive neuroectodermal tumor. A 14-year-old girl attended to the Ear Nose Throat Clinic with the complaint of progressive painless swelling mass for 2 months on the right side of the face. Neck magnetic resonance imaging showed 3.5 × 2.5 × 2-cm isointense mass on T1 and hyperintense on T2 sequences. There was no pathological lymphadenopathy on computed tomographic scan. As a result of mandibular cortical invasion seen on computed tomographic scan, radical surgical excision was decided as surgical treatment. Total parotidectomy with preserving facial nerve and partial mandibulectomy with a 2-cm margin of safety were done, and reconstruction plaque applied to the mandible. Two lymph nodes were seen at the submandibular region. For this reason, prophylactic supraomohyoid neck dissection had also been performed. Pathological assessment proved the diagnosis of PNET, and chemoradiotherapy was planned for the patient.To our knowledge, this is the second reported case in literature. In this present case, peripheral neuroectodermal tumor in the masseter muscle and its diagnosis and treatment process were reported with literature review.

  1. Possible controls on the bulk composition of the earth - Implications for the origin of the earth and moon

    Science.gov (United States)

    Smith, J. V.

    1977-01-01

    It is pointed out that speculation regarding the bulk chemical composition of the earth, especially its radial distribution, is important for testing ideas on the origin of the earth-moon system. Definitive solutions are, however, unattainable. The reported investigation is concerned with an attempt to select the more plausible possibilities. The evidence on the chemical distribution in the earth is examined and the resulting models of bulk composition are used to check the plausibility of the Ganapathy-Anders model. It is suggested that the chemistry of the earth and moon can be modeled more plausibly in the context of slow, cool accretion of the earth and either simultaneous accretion or disintegrative capture of the moon than by fission or volatilization models based on a hot earth. Many possible aspects need detailed quantitative study including the relation between U content, other heat sources, and heat flow on earth.

  2. A Note on Primitive Permutation Groups of Prime Power Degree

    OpenAIRE

    Qian Cai; Hua Zhang

    2015-01-01

    Primitive permutation groups of prime power degree are known to be affine type, almost simple type, and product action type. At the present stage finding an explicit classification of primitive groups of affine type seems untractable, while the product action type can usually be reduced to almost simple type. In this paper, we present a short survey of the development of primitive groups of prime power degree, together with a brief description on such groups.

  3. On the biological plausibility of Wind Turbine Syndrome.

    Science.gov (United States)

    Harrison, Robert V

    2015-01-01

    An emerging environmental health issue relates to potential ill-effects of wind turbine noise. There have been numerous suggestions that the low-frequency acoustic components in wind turbine signals can cause symptoms associated with vestibular system disorders, namely vertigo, nausea, and nystagmus. This constellation of symptoms has been labeled as Wind Turbine Syndrome, and has been identified in case studies of individuals living close to wind farms. This review discusses whether it is biologically plausible for the turbine noise to stimulate the vestibular parts of the inner ear and, by extension, cause Wind Turbine Syndrome. We consider the sound levels that can activate the semicircular canals or otolith end organs in normal subjects, as well as in those with preexisting conditions known to lower vestibular threshold to sound stimulation.

  4. Hamiltonian formulation of time-dependent plausible inference

    CERN Document Server

    Davis, Sergio

    2014-01-01

    Maximization of the path information entropy is a clear prescription for performing time-dependent plausible inference. Here it is shown that, following this prescription under the assumption of arbitrary instantaneous constraints on position and velocity, a Lagrangian emerges which determines the most probable trajectory. Deviations from the probability maximum can be consistently described as slices in time by a Hamiltonian, according to a nonlinear Langevin equation and its associated Fokker-Planck equation. The connections unveiled between the maximization of path entropy and the Langevin/Fokker-Planck equations imply that missing information about the phase space coordinate never decreases in time, a purely information-theoretical version of the Second Law of Thermodynamics. All of these results are independent of any physical assumptions, and thus valid for any generalized coordinate as a function of time, or any other parameter. This reinforces the view that the Second Law is a fundamental property of ...

  5. Alkaloids from Pandanus amaryllifolius: Isolation and Their Plausible Biosynthetic Formation.

    Science.gov (United States)

    Tsai, Yu-Chi; Yu, Meng-Lun; El-Shazly, Mohamed; Beerhues, Ludger; Cheng, Yuan-Bin; Chen, Lei-Chin; Hwang, Tsong-Long; Chen, Hui-Fen; Chung, Yu-Ming; Hou, Ming-Feng; Wu, Yang-Chang; Chang, Fang-Rong

    2015-10-23

    Pandanus amaryllifolius Roxb. (Pandanaceae) is used as a flavor and in folk medicine in Southeast Asia. The ethanolic crude extract of the aerial parts of P. amaryllifolius exhibited antioxidant, antibiofilm, and anti-inflammatory activities in previous studies. In the current investigation, the purification of the ethanolic extract yielded nine new compounds, including N-acetylnorpandamarilactonines A (1) and B (2); pandalizines A (3) and B (4); pandanmenyamine (5); pandamarilactones 2 (6) and 3 (7), and 5(E)-pandamarilactonine-32 (8); and pandalactonine (9). The isolated alkaloids, with either a γ-alkylidene-α,β-unsaturated-γ-lactone or γ-alkylidene-α,β-unsaturated-γ-lactam system, can be classified into five skeletons including norpandamarilactonine, indolizinone, pandanamine, pandamarilactone, and pandamarilactonine. A plausible biosynthetic route toward 1-5, 7, and 9 is proposed.

  6. Complex Learning in Bio-plausible Memristive Networks.

    Science.gov (United States)

    Deng, Lei; Li, Guoqi; Deng, Ning; Wang, Dong; Zhang, Ziyang; He, Wei; Li, Huanglong; Pei, Jing; Shi, Luping

    2015-06-19

    The emerging memristor-based neuromorphic engineering promises an efficient computing paradigm. However, the lack of both internal dynamics in the previous feedforward memristive networks and efficient learning algorithms in recurrent networks, fundamentally limits the learning ability of existing systems. In this work, we propose a framework to support complex learning functions by introducing dedicated learning algorithms to a bio-plausible recurrent memristive network with internal dynamics. We fabricate iron oxide memristor-based synapses, with well controllable plasticity and a wide dynamic range of excitatory/inhibitory connection weights, to build the network. To adaptively modify the synaptic weights, the comprehensive recursive least-squares (RLS) learning algorithm is introduced. Based on the proposed framework, the learning of various timing patterns and a complex spatiotemporal pattern of human motor is demonstrated. This work paves a new way to explore the brain-inspired complex learning in neuromorphic systems.

  7. Optimisation in Quadric Primitive Representation and Classification from Range Data

    Institute of Scientific and Technical Information of China (English)

    ZHANGLei; WANGGuoyu; HOUKESZweitze

    2004-01-01

    This paper focuses the modelling of uncertainties occurring in feature extraction from range images for surface-based primitive classification. The feature descriptor of a surface primitive consists of the algebraic invariants extracted from a quadric patch, which are concerned in applications of man-made object recognition. The uncertainties of the estimates are cbaracterised with their covariance matrices. We propose an explicit probabilistic model to describe the statistical performance of the feature descriptor. Consequently, the classification of surface primitive and sensor-based modelling process can be implemented within an optimal framework. Experimental results of primitive classification with synthetic and real range data are presented.

  8. Primitive defenses: cognitive aspects and therapeutic handling.

    Science.gov (United States)

    Groh, L S

    In this paper the primitive defenses first described by Melanie Klein under the label of "schizoid mechanisms" are examined. The defenses considered are splitting the pathological uses of identification and projective identification, and the psychotic forms of denial. This examination is twofold: (1) the cognitive aspects of these defenses as described in terms of concepts developed by Jean Piaget; (2) concrete examples of the operation of these defenses during the treatment of schizophrenic patients are given and the effects of interventions based on the cognitive analysis are described. It is stressed that at times interventions, such as interpretation and confrontation, based on cognitive analysis, can temporarily and in some instances even permanently stop the operation of these defenses, allowing emotionally meaningful material to emerge which expedites the therapeutic process.

  9. Peripheral Primitive Neuroectodermal Tumor of the Pelvis

    Directory of Open Access Journals (Sweden)

    Zohreh Yousefi

    2014-01-01

    Full Text Available The primitive neuroectodermal tumor (PNET belongs to a group of highly malignant tumors and is composed of small round cells of a neuroectodermal origin. Categorized in the same tumor family as Ewing sarcoma, the PNET is most likely to occur in bones and soft tissues. However, a small number of PNET cases arising in the pelvis have been reported as well. We present three cases of pelvic PNET: two cases in the ovary and one case in the broad ligament. The PNET often exhibits aggressive clinical behavior with worse outcomes than other small round cell tumors. The significant prognostic factors of the PNET include site of tumor, volume of neoplasm, and presence of metastasis. The treatment protocol is multimodal and includes local surgical treatment followed by chemotherapy. We herein describe three PNET cases as a rare entity in the pelvis. Pelvic PNETs should be included in the differential diagnosis of pelvic masses.

  10. On prime non-primitive von Neumann regular algebras

    CERN Document Server

    Abrams, Gene; Rangaswamy, Kulumani M

    2011-01-01

    Let $E$ be any directed graph, and $K$ any field. We classify those graphs $E$ for which the Leavitt path algebra $L_K(E)$ is primitive. As a consequence, we obtain classes of examples of von Neumann regular prime rings which are not primitive.

  11. Transferrring primitive elements of skill within and between tasks

    NARCIS (Netherlands)

    Gittelson, Logan; Taatgen, Niels

    2014-01-01

    The primitive elements of skill theory proposes a set of approximately 2000 primitive information processing elements (PRIMs) (Taatgen, 2013) that compose all cognitive acts by combining and recombining to produce learning and transfer. By this theory, learning is transfer and transfer results from

  12. Liderazgo preventivo para la universidad. Una experiencia plausible

    Directory of Open Access Journals (Sweden)

    Alejandro Rodríguez Rodríguez

    2015-06-01

    Full Text Available El desarrollo del liderazgo, en el ámbito educativo superior, busca soluciones de aplicación inmediata a contextos en que todo líder se desenvuelve, pero se diluye el sustento teórico-práctico en la formación del líder que posibilite entender los procesos intelectivos durante la toma de decisiones. El paradigma de convergencia entre el método antropológico lonerganiano, la comunidad de aprendizaje vygotskiana y una relectura del sistema preventivo salesiano se presentan como propuesta plausible de formación al liderazgo preventivo entre los diversos actores de una comunidad universitaria. Un estudio de caso de la Universidad Salesiana en México empleando un método mixto de investigación, facilita una relectura del liderazgo desde una óptica preventiva como posibilidad de convergencia en un diálogo interdisciplinar. Los resultados teórico-práctico propuestos y examinados se muestran como herramienta útil para evaluar, enriquecer y renovar la teoría sobre el líder y el desarrollo de liderazgo en las universidades frente a una sociedad globalizada.

  13. A perspective on SIDS pathogenesis. The hypotheses: plausibility and evidence

    Directory of Open Access Journals (Sweden)

    Goldwater Paul N

    2011-05-01

    Full Text Available Abstract Several theories of the underlying mechanisms of Sudden Infant Death Syndrome (SIDS have been proposed. These theories have born relatively narrow beach-head research programs attracting generous research funding sustained for many years at expense to the public purse. This perspective endeavors to critically examine the evidence and bases of these theories and determine their plausibility; and questions whether or not a safe and reasoned hypothesis lies at their foundation. The Opinion sets specific criteria by asking the following questions: 1. Does the hypothesis take into account the key pathological findings in SIDS? 2. Is the hypothesis congruent with the key epidemiological risk factors? 3. Does it link 1 and 2? Falling short of any one of these answers, by inference, would imply insufficient grounds for a sustainable hypothesis. Some of the hypotheses overlap, for instance, notional respiratory failure may encompass apnea, prone sleep position, and asphyxia which may be seen to be linked to co-sleeping. For the purposes of this paper, each element will be assessed on the above criteria.

  14. A plausible explanation for male dominance in typhoid ileal perforation

    Directory of Open Access Journals (Sweden)

    Khan M

    2012-11-01

    Full Text Available Mohammad KhanDepartment of Microbiology, College of Medicine, Chichiri, Blantyre, MalawiAbstract: The phenomenon of consistent male dominance in typhoid ileal perforation (TIP is not well understood. It cannot be explained on the basis of microbial virulence, Peyer's patch anatomy, ileal wall thickness, gastric acidity, host genetic factors, or sex-linked bias in hospital attendance. The cytokine response to an intestinal infection in males is predominantly proinflammatory as compared with that in females, presumably due to differences in the sex hormonal milieu. Sex hormone receptors have been detected on lymphocytes and macrophages, including on Peyer's patches, inflammation of which (probably similar to the Shwartzman reaction/Koch phenomenon is the forerunner of TIP, and is not excluded from the regulatory effects of sex hormones. Hormonal control of host-pathogen interaction may override genetic control. Environmental exposure to Salmonella typhi may be more frequent in males, presumably due to sex-linked differences in hygiene practices and dining-out behavior. A plausible explanation of male dominance in TIP could include sex-linked differences in the degree of natural exposure of Peyer's patches to S. typhi. An alternative explanation may include sexual dimorphism in host inflammatory response patterns in Peyer's patches that have been induced by S. typhi. Both hypotheses are testable.Keywords: explanation, dominance, male, perforation, ileum, typhoid

  15. A plausible explanation for male dominance in typhoid ileal perforation.

    Science.gov (United States)

    Khan, Mohammad

    2012-01-01

    The phenomenon of consistent male dominance in typhoid ileal perforation (TIP) is not well understood. It cannot be explained on the basis of microbial virulence, Peyer's patch anatomy, ileal wall thickness, gastric acidity, host genetic factors, or sex-linked bias in hospital attendance. The cytokine response to an intestinal infection in males is predominantly proinflammatory as compared with that in females, presumably due to differences in the sex hormonal milieu. Sex hormone receptors have been detected on lymphocytes and macrophages, including on Peyer's patches, inflammation of which (probably similar to the Shwartzman reaction/Koch phenomenon) is the forerunner of TIP, and is not excluded from the regulatory effects of sex hormones. Hormonal control of host-pathogen interaction may override genetic control. Environmental exposure to Salmonella typhi may be more frequent in males, presumably due to sex-linked differences in hygiene practices and dining-out behavior. A plausible explanation of male dominance in TIP could include sex-linked differences in the degree of natural exposure of Peyer's patches to S. typhi. An alternative explanation may include sexual dimorphism in host inflammatory response patterns in Peyer's patches that have been induced by S. typhi. Both hypotheses are testable.

  16. Plausible rice yield losses under future climate warming.

    Science.gov (United States)

    Zhao, Chuang; Piao, Shilong; Wang, Xuhui; Huang, Yao; Ciais, Philippe; Elliott, Joshua; Huang, Mengtian; Janssens, Ivan A; Li, Tao; Lian, Xu; Liu, Yongwen; Müller, Christoph; Peng, Shushi; Wang, Tao; Zeng, Zhenzhong; Peñuelas, Josep

    2016-12-19

    Rice is the staple food for more than 50% of the world's population(1-3). Reliable prediction of changes in rice yield is thus central for maintaining global food security. This is an extraordinary challenge. Here, we compare the sensitivity of rice yield to temperature increase derived from field warming experiments and three modelling approaches: statistical models, local crop models and global gridded crop models. Field warming experiments produce a substantial rice yield loss under warming, with an average temperature sensitivity of -5.2 ± 1.4% K(-1). Local crop models give a similar sensitivity (-6.3 ± 0.4% K(-1)), but statistical and global gridded crop models both suggest less negative impacts of warming on yields (-0.8 ± 0.3% and -2.4 ± 3.7% K(-1), respectively). Using data from field warming experiments, we further propose a conditional probability approach to constrain the large range of global gridded crop model results for the future yield changes in response to warming by the end of the century (from -1.3% to -9.3% K(-1)). The constraint implies a more negative response to warming (-8.3 ± 1.4% K(-1)) and reduces the spread of the model ensemble by 33%. This yield reduction exceeds that estimated by the International Food Policy Research Institute assessment (-4.2 to -6.4% K(-1)) (ref. 4). Our study suggests that without CO2 fertilization, effective adaptation and genetic improvement, severe rice yield losses are plausible under intensive climate warming scenarios.

  17. A biologically plausible embodied model of action discovery

    Directory of Open Access Journals (Sweden)

    Rufino eBolado-Gomez

    2013-03-01

    Full Text Available During development, animals can spontaneously discover action-outcomepairings enabling subsequent achievement of their goals. We present abiologically plausible embodied model addressing key aspects of thisprocess. The biomimetic model core comprises the basal ganglia and itsloops through cortex and thalamus. We incorporate reinforcementlearning with phasic dopamine supplying a sensory prediction error,signalling 'surprising' outcomes. Phasic dopamine is used in acorticostriatal learning rule which is consistent with recent data. Wealso hypothesised that objects associated with surprising outcomesacquire 'novelty salience' contingent on the predicability of theoutcome. To test this idea we used a simple model of predictiongoverning the dynamics of novelty salience and phasic dopamine. Thetask of the virtual robotic agent mimicked an in vivo counterpart(Gancarz et al., 2011 and involved interaction with a target objectwhich caused a light flash, or a control object which did not.Learning took place according to two schedules. In one, the phasicoutcome was delivered after interaction with the target in anunpredictable way which emulated the in vivo protocol. Without noveltysalience, the model was unable to account for the experimental data.In the other schedule, the phasic outcome was reliably delivered andthe agent showed a rapid increase in the number of interactions withthe target which then decreased over subsequent sessions. We arguethis is precisely the kind of change in behaviour required torepeatedly present representations of context, action and outcome, toneural networks responsible for learning action-outcome contingency.The model also showed corticostriatal plasticity consistent withlearning a new action in basal ganglia. We conclude that actionlearning is underpinned by a complex interplay of plasticity andstimulus salience, and that our model contains many of the elementsfor biological action discovery to take place.

  18. Changing beliefs about implausible autobiographical events: a little plausibility goes a long way.

    Science.gov (United States)

    Mazzoni, G A; Loftus, E F; Kirsch, I

    2001-03-01

    Three experiments investigated the malleability of perceived plausibility and the subjective likelihood of occurrence of plausible and implausible events among participants who had no recollection of experiencing them. In Experiment 1, a plausibility-enhancing manipulation (reading accounts of the occurrence of events) combined with a personalized suggestion increased the perceived plausibility of the implausible event, as well as participants' ratings of the likelihood that they had experienced it. Plausibility and likelihood ratings were uncorrelated. Subsequent studies showed that the plausibility manipulation alone was sufficient to increase likelihood ratings but only if the accounts that participants read were set in a contemporary context. These data suggest that false autobiographical beliefs can be induced in clinical and forensic contexts even for initially implausible events.

  19. Two Beyond-Primitive Extrasolar Planetesimals

    CERN Document Server

    Xu, S; Klein, B; Koester, D; Zuckerman, B

    2013-01-01

    Using the Cosmic Origins Spectrograph onboard the Hubble Space Telescope, we have obtained high-resolution ultraviolet observations of GD 362 and PG 1225-079, two helium-dominated, externally-polluted white dwarfs. We determined or placed useful upper limits on the abundances of two key volatile elements, carbon and sulfur, in both stars; we also constrained the zinc abundance in PG 1225-079. In combination with previous optical data, we find strong evidence that each of these two white dwarfs has accreted a parent body that has evolved beyond primitive nebular condensation. The planetesimal accreted onto GD 362 had a bulk composition roughly similar to that of a mesosiderite meteorite based on a reduced chi-squared comparison with solar system objects; however, additional material is required to fully reproduce the observed mid-infrared spectrum for GD 362. No single meteorite can reproduce the unique abundance pattern observed in PG 1225-079; the best fit model requires a blend of ureilite and mesosiderite ...

  20. Renal Primitive Neuroectodermal Tumor: A Case Report.

    Science.gov (United States)

    Yang, Cheng; Xu, Hanjiang; Zhou, Jun; Hao, Zongyao; Wang, Jianzhong; Lin, Changmin; Zhang, Li; Zhu, Xia; Liang, Chaozhao

    2015-12-01

    Primitive neuroectodermal tumor (PNET) is a malignant small round cell tumor and typically arises from bone or soft tissue in adolescents and young adults. Renal PNET is extraordinarily rare and exhibits highly aggressive biological behavior with poor prognosis.We present here a new case of renal PNET in a 31-year-old female. The patients were referred to our hospital because of left flank pain with nausea and vomiting for 1 week. A computed tomography scan revealed a 14.7 × 12.7 cm well-defined, unevenly mass lesion with both solid and cystic components and the tumor was not enhanced uniformly.A preoperative diagnosis of cystic renal cell carcinoma and urinary tract infection was made. The patient undergone anti-inflammatory therapy followed by a left radical nephrectomy. Taken with morphological pattern and immunohistochemical markers, a diagnosis of renal PNET was made. Two cycles of combined chemotherapy were executed. At the 14-month follow-up, no evidence of metastasis or recurrence was indicated.This case reminds clinicians that for adolescents and young adults with a suspicious renal mass, a diagnosis of renal PNET should be always considered. An initial surgery followed by radiotherapy and chemotherapy is suggested for the therapeutic management.

  1. Indigenous amino acids in primitive CR meteorites

    CERN Document Server

    Martins, Z; Orzechowska, G E; Fogel, M L; Ehrenfreund, P

    2008-01-01

    CR meteorites are among the most primitive meteorites. In this paper, we report the first measurements of amino acids in Antarctic CR meteorites, two of which show the highest amino acid concentrations ever found in a chondrite. EET92042, GRA95229 and GRO95577 were analyzed for their amino acid content using high performance liquid chromatography with UV fluorescence detection (HPLC-FD) and gas chromatographymass spectrometry (GC-MS). Our data show that EET92042 and GRA95229 are the most amino acid-rich chondrites ever analyzed, with total amino acid concentrations ranging from 180 parts-per-million (ppm) to 249 ppm. GRO95577, however, is depleted in amino acids. The most abundant amino acids present in the EET92042 and GRA95229 meteorites are the alpha-amino acids glycine, isovaline, alpha-aminoisobutyric acid (alpha-AIB), and alanine, with delta13C values ranging from +31.6per mil to +50.5per mil. The carbon isotope results together with racemic enantiomeric ratios determined for most amino acids strongly i...

  2. View Invariant Gesture Recognition using 3D Motion Primitives

    DEFF Research Database (Denmark)

    Holte, Michael Boelstoft; Moeslund, Thomas B.

    2008-01-01

    This paper presents a method for automatic recognition of human gestures. The method works with 3D image data from a range camera to achieve invariance to viewpoint. The recognition is based solely on motion from characteristic instances of the gestures. These instances are denoted 3D motion...... primitives. The method extracts 3D motion from range images and represent the motion from each input frame in a view invariant manner using harmonic shape context. The harmonic shape context is classified as a 3D motion primitive. A sequence of input frames results in a set of primitives that are classified...

  3. Primitive neuroectodermal tumor of the posterior mandible: A case report

    Directory of Open Access Journals (Sweden)

    Monal B. Yuwanati

    2013-03-01

    Full Text Available Primitive neuroectodermal tumor is a term used to describea category of neoplasms of neuroectodermal originwith variable cell differentiation. These tumors arise inmany places throughout the body. The chest wall, larynx,abdomen, and pelvis being the most common primarysites; in rare cases, they occur in the head and neck area.Only 3% of cases have been reported within the skull andjaws. In this report, a rare case of primitive neuroectodermaltumor in the left side posterior mandible in a youngadult is described. J Clin Exp Invest 2013; 4 (1: 101-104Key words: Neuroectodermal tumors, primitive, peripheral,oral cavity, mandible

  4. A primitive enzyme for a primitive cell: the protease required for excystation of Giardia.

    Science.gov (United States)

    Ward, W; Alvarado, L; Rawlings, N D; Engel, J C; Franklin, C; McKerrow, J H

    1997-05-02

    Protozoan parasites of the genus Giardia are one of the earliest lineages of eukaryotic cells. To initiate infection, trophozoites emerge from a cyst in the host. Excystation is blocked by specific cysteine protease inhibitors. Using a biotinylated inhibitor, the target protease was identified and its corresponding gene cloned. The protease was localized to vesicles that release their contents just prior to excystation. The Giardia protease is the earliest known branch of the cathepsin B family. Its phylogeny confirms that the cathepsin B lineage evolved in primitive eukaryotic cells, prior to the divergence of plant and animal kingdoms, and underscores the diversity of cellular functions that this enzyme family facilitates.

  5. Hf-W chronometry of primitive achondrites

    Science.gov (United States)

    Schulz, T.; Münker, C.; Mezger, K.; Palme, H.

    2010-03-01

    Metal segregation and silicate melting on asteroids are the most incisive differentiation events in the early evolution of planetary bodies. The timing of these events can be constrained using the short-lived 182Hf- 182W radionuclide system. Here we present new 182Hf- 182W data for major types of primitive achondrites including acapulcoites, winonaites and one lodranite. These meteorites are of particular interest because they show only limited evidence for partial melting of silicates and are therefore intermediate between chondrites and achondrites. For acapulcoites we derived a 182Hf- 182W age of Δ tCAI = 4.1 +1.2/ -1.1 Ma. A model age for winonaite separates calculated from the intercept of the isochron defines an age of Δ tCAI = 4.8 +3.1/ -2.6 Ma (assuming a bulk Hf/W ratio of ˜1.2). Both ages most likely define primary magmatic events on the respective parent bodies, such as melting of metal, although metal stayed in place and did not segregate to form a core. A later thermal event is responsible for resetting of the winonaite isochron, yielding an age of Δ tCAI = 14.3 +2.7/ -2.2 Ma, significantly younger than the model age. Assuming a co-genetic relationship between winonaites and silicates present in IAB iron meteorites (based on oxygen isotope composition) and including data by Schulz et al. (2009), a common parent body chronology can be established. Magmatic activity occurred between ˜1.5 and 5 Ma after CAIs. More than 5 Ma later, intensive thermal metamorphism has redistributed Hf-W. Average cooling rates calculated for the winonaite/IAB parent asteroid range between ˜35 and ˜4 K/Ma, most likely reflecting different burial depths. Cooling rates obtained for acapulcoites were ˜40 K/Ma to ˜720 K and then ˜3 K/Ma to ˜550 K. Accretion and subsequent magmatism on the acapulcoite parent body occurred slightly later if compared to most achondrite parent bodies (e.g., angrites, ureilites and eucrites), in this case supporting the concept of an inverse

  6. Radiotherapy of supratentorial primitive neuroectodermal tumor

    Energy Technology Data Exchange (ETDEWEB)

    Kim, D. Y. [Sung Kyun Kwan Univ., Seoul (Korea, Republic of). Coll. of Medicine; Kim, I. H.; Yoo, H. J. [Seoul National Univ., Seoul (Korea, Republic of). Coll. of Medicine; Cho, Y. K. [Inha Univ., Inchon (Korea, Republic of). Coll. of Medicine

    1997-03-01

    To evaluate the efficacy of combined treatment of surgery and chemoradiotherapy for supratentorial primitive neuroectodermal tumors (SPNET) and obtain the prognostic factors and complications. The age of 18 patients ranged from 1 to 27 years (median = 5 years). There were 12 males and 6 females. The extents of surgery were gross total (n=9), subtotal (n=8), biopsy only (n=1). Craniospinal radiotherapy was delivered to all the patients except 2 patients who were treated only with the whole brain and primary lesion. Radiation dose were 3120 - 5800 cGy (median=5460) to primary mass, 1500 - 4200 cGy (median = 3600 cGy) to the whole brain and 1320 - 3600 cGy (median = 2400 cGy) to the spinal axis. Chemotherapy was done in 13 patients. Median follow-up period was 45 months ranged from 1 to 89 months. Patterns of failure were as follows; local recurrence (1), multiple intracranial recurrence (2), spinal seeding (3), craniospinal seeding (2) and multiple bone metastasis (1). Two of two patients who did not received craniospinal radiotherapy failed at spinal are. All the relapsed cases died at 1 to 13 months after diagnosis of progression. The 2- and 5-year overall survival rates were 61% and 49%, respectively. The age, sex, tumor location did not influence the survival bu aggressive resection with combined chemotherapy showed better outcome. Among 9 survivors, complications were detected as radiation necrosis (n=1), hypopituitarism (n=2), cognitive defect (n=1), memory deficit (n=1), growth retardation (n=1). To improve the results of treatment of SPENT, maximal surgical resection followed by radiation therapy and chemotherapy is necessary. The extended radiation field including craniospinal axis may reduce the recurrence in spinal axis. (author).

  7. The primitive derivation and freeness of multi-Coxeter arrangements

    OpenAIRE

    Yoshinaga, Masahiko

    2002-01-01

    We will prove the freeness of multi-Coxeter arrangements by constructing a basis of the module of vector fields which contact to each reflecting hyperplanes with some multiplicities using K. Saito's theory of primitive derivation.

  8. Uterine primitive neuroectodermal tumor with adenosarcoma: a case report

    Directory of Open Access Journals (Sweden)

    Chawla Indu

    2010-06-01

    Full Text Available Abstract Introduction Primitive neuroectodermal tumor of the uterus is extremely rare. They occur as either pure primitive neuroectodermal tumors or admixed with neoplasms of mullerian origin. Case presentation A case of uterine primitive neuroectodermal tumor with adenosarcoma in a 50-year-old Asian Indian woman is presented. Histologically, the neoplasm displayed perivascular pseudorosettes and occasional Homer-Wright rosettes. A strong positivity for neuronspecific enolase and synaptophysin was noted, while chromogranin and CD99 were negative. Merging imperceptibly with the neuroectodermal components were the areas of adenosarcoma. Conclusion To the best of our knowledge, this report represents the second case of a uterine primitive neuroectodermal tumor with an admixed adenosarcoma.

  9. 古韵岜沙%Primitive Landscape in Basha

    Institute of Scientific and Technical Information of China (English)

    李也青

    2001-01-01

    Lying in the southeast of Guizhou Province, Basha, a small village of Miao Nationality, shows the painter a primitive landscape. He believes simplicity is a common element both in painting and in the nature.

  10. The Artist/Craftsman/Teacher: And Primitive Pottery.

    Science.gov (United States)

    Verbalaitis, Victor

    1978-01-01

    In two related articles, the author describes (1) a field trip during which his high school ceramics club collected clay from the outdoors and (2) the process he used to create primitive pottery pieces from such material. (SJL)

  11. Zero Viscosity Limit for Analytic Solutions of the Primitive Equations

    Science.gov (United States)

    Kukavica, Igor; Lombardo, Maria Carmela; Sammartino, Marco

    2016-10-01

    The aim of this paper is to prove that the solutions of the primitive equations converge, in the zero viscosity limit, to the solutions of the hydrostatic Euler equations. We construct the solution of the primitive equations through a matched asymptotic expansion involving the solution of the hydrostatic Euler equation and boundary layer correctors as the first order term, and an error that we show to be {O(√{ν})}. The main assumption is spatial analyticity of the initial datum.

  12. Peripheral Primitive Neuroectodermal Tumor of the Stomach: A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Park, Woon Ju; Cho, June Sik; Shin, Kyung Sook; Jeong, Hyung Yong; Noh; Seung Moo; Song, Kyu Sang [Chungnam University Hospital, Daejeon (Korea, Republic of)

    2010-06-15

    Peripheral primitive neuroectodermal tumors (peripheral PNETs) are very rare and highly aggressive soft tissue malignancies originating from the neural crest. To the best of our knowledge, only a few cases of peripheral PNETs of the stomach have been reported in the literature. We report a case of large peripheral primitive neuroectodermal tumor of the stomach with MDCT findings in a 22-year-old man presenting epigastric pain and vomiting

  13. Primary spinal primitive neuroectodermal tumor on MR imaging.

    Science.gov (United States)

    Thoriya, Prashant J; Watal, Pankaj; Bahri, Nandini U; Rathod, Ketan

    2015-01-01

    Neoplasms in the region of filum terminale are not uncommon. Myxopapillary ependymoma is the commonest tumor at this location. The differentials reported for this entity are nerve sheath tumor, meningioma, paraganglioma, intradural metastases, lymphoma, other varieties of ependymoma, subependymoma, astrocytoma, ganglioglioma, hemangioblastoma, and primitive neuroectodermal tumor (PNET). PNET may very rarely present as an intradural thoracolumbar mass. We present pre- and post-therapy magnetic resonance imaging (MRI) features of a patient with proven primary spinal primitive neuroectodermal tumor (PSPNET) of peripheral subtype.

  14. PRIMITIVE IDEALS OF TOEPLITZ ALGEBRA OF ORDERED GROUPS

    Directory of Open Access Journals (Sweden)

    Rizky Rosjanuardi

    2012-06-01

    Full Text Available The topology on primitive ideal space of Toeplitz algebras of totally ordered abelian groups can be identified through the upwards-looking topology if and only if the chain of order ideals is well-ordered. We describe the topology on primitive ideal space of Toeplitz algebra of totally ordered abelian groups when the chain of order ideals is not well ordered.

  15. Cometary dust: the diversity of primitive refractory grains

    Science.gov (United States)

    Wooden, D. H.; Ishii, H. A.; Zolensky, M. E.

    2017-05-01

    Comet dust is primitive and shows significant diversity. Our knowledge of the properties of primitive cometary particles has expanded significantly through microscale investigations of cosmic dust samples (anhydrous interplanetary dust particles (IDPs), chondritic porous (CP) IDPs and UltraCarbonaceous Antarctic micrometeorites, Stardust and Rosetta), as well as through remote sensing (Spitzer IR spectroscopy). Comet dust are aggregate particles of materials unequilibrated at submicrometre scales. We discuss the properties and processes experienced by primitive matter in comets. Primitive particles exhibit a diverse range of: structure and typology; distribution of constituents; concentration and form of carbonaceous and refractory organic matter; Mg- and Fe-contents of the silicate minerals; sulfides; existence/abundance of type II chondrule fragments; high-temperature calcium-aluminium inclusions and ameboid-olivine aggregates; and rarely occurring Mg-carbonates and magnetite, whose explanation requires aqueous alteration on parent bodies. The properties of refractory materials imply there were disc processes that resulted in different comets having particular selections of primitive materials. The diversity of primitive particles has implications for the diversity of materials in the protoplanetary disc present at the time and in the region where the comets formed. This article is part of the themed issue 'Cometary science after Rosetta'.

  16. The origin of volatiles in the Earth's mantle

    Science.gov (United States)

    Hier-Majumder, Saswata; Hirschmann, Marc M.

    2017-08-01

    The Earth's deep interior contains significant reservoirs of volatiles such as H, C, and N. Due to the incompatible nature of these volatile species, it has been difficult to reconcile their storage in the residual mantle immediately following crystallization of the terrestrial magma ocean (MO). As the magma ocean freezes, it is commonly assumed that very small amounts of melt are retained in the residual mantle, limiting the trapped volatile concentration in the primordial mantle. In this article, we show that inefficient melt drainage out of the freezing front can retain large amounts of volatiles hosted in the trapped melt in the residual mantle while creating a thick early atmosphere. Using a two-phase flow model, we demonstrate that compaction within the moving freezing front is inefficient over time scales characteristic of magma ocean solidification. We employ a scaling relation between the trapped melt fraction, the rate of compaction, and the rate of freezing in our magma ocean evolution model. For cosmochemically plausible fractions of volatiles delivered during the later stages of accretion, our calculations suggest that up to 77% of total H2O and 12% of CO2 could have been trapped in the mantle during magma ocean crystallization. The assumption of a constant trapped melt fraction underestimates the mass of volatiles in the residual mantle by more than an order of magnitude.Plain Language SummaryThe Earth's deep interior contains substantial amounts of volatile elements like C, H, and N. How these elements got sequestered in the Earth's interior has long been a topic of debate. It is generally assumed that most of these elements escaped the interior of the Earth during the first few hundred thousand years to create a primitive atmosphere, leaving the mantle reservoir nearly empty. In this work, we show that the key to this paradox involves the very early stages of crystallization of the mantle from a global magma ocean. Using numerical models, we show

  17. Comet Dust: The Diversity of "Primitive" Particles and Implications

    Science.gov (United States)

    Wooden, Diane H.; Ishii, Hope A.; Bradley, John P.; Zolensky, Michael E.

    2016-01-01

    Comet dust is primitive and shows significant diversity. Our knowledge of the properties of primitive particles has expanded significantly through microscale investigations of cosmic dust samples ( IDP's(Interplanetary Dust Particles) and AMM's (Antarctic Micrometeorites)) and of comet dust samples (Stardust and Rosetta's COSIMA), as well as through remote sensing (spectroscopy and imaging) via Spitzer and via spacecraft encounters with 103P/Hartley 2 and 67P/Churyumov-Gerasimenko. Microscale investigations show that comet dust and cosmic dust are particles of unequilibrated materials, including aggregates of materials unequilibrated at submicron scales. We call unequilibrated materials "primitive" and we deduce they were incorporated into ice-rich (H2O-, CO2-, and CO-ice) parent bodies that remained cold, i.e., into comets, because of the lack of aqueous or thermal alteration since particle aggregation; yet some Stardust olivines suggest mild thermal metamorphism. Primitive particles exhibit a diverse range of: structure and typology; size and size distribution of constituents; concentration and form of carbonaceous and organic matter; D-, N-, and O- isotopic enhancements over solar; Mg-, Fe-contents of the silicate minerals; the compositions and concentrations of sulfides, and of less abundant mineral species such as chondrules, CAIs and carbonates. The uniformity within a group of samples points to: aerodynamic sorting of particles and/or particle constituents; the inclusion of a limited range of oxygen fugacities; the inclusion or exclusion of chondrules; a selection of organics. The properties of primitive particles imply there were disk processes that resulted in different comets having particular selections of primitive materials. The diversity of primitive particles has implications for the diversity of materials in the protoplanetary disk present at the time and in the region where the comets formed.

  18. Polycyclic aromatic hydrocarbons as plausible prebiotic membrane components.

    Science.gov (United States)

    Groen, Joost; Deamer, David W; Kros, Alexander; Ehrenfreund, Pascale

    2012-08-01

    Aromatic molecules delivered to the young Earth during the heavy bombardment phase in the early history of our solar system were likely to be among the most abundant and stable organic compounds available. The Aromatic World hypothesis suggests that aromatic molecules might function as container elements, energy transduction elements and templating genetic components for early life forms. To investigate the possible role of aromatic molecules as container elements, we incorporated different polycyclic aromatic hydrocarbons (PAH) in the membranes of fatty acid vesicles. The goal was to determine whether PAH could function as a stabilizing agent, similar to the role that cholesterol plays in membranes today. We studied vesicle size distribution, critical vesicle concentration and permeability of the bilayers using C(6)-C(10) fatty acids mixed with amphiphilic PAH derivatives such as 1-hydroxypyrene, 9-anthracene carboxylic acid and 1,4 chrysene quinone. Dynamic Light Scattering (DLS) spectroscopy was used to measure the size distribution of vesicles and incorporation of PAH species was established by phase-contrast and epifluorescence microscopy. We employed conductimetric titration to determine the minimal concentration at which fatty acids could form stable vesicles in the presence of PAHs. We found that oxidized PAH derivatives can be incorporated into decanoic acid (DA) vesicle bilayers in mole ratios up to 1:10 (PAH:DA). Vesicle size distribution and critical vesicle concentration were largely unaffected by PAH incorporation, but 1-hydroxypyrene and 9-anthracene carboxylic acid lowered the permeability of fatty acid bilayers to small solutes up to 4-fold. These data represent the first indication of a cholesterol-like stabilizing effect of oxidized PAH derivatives in a simulated prebiotic membrane.

  19. Partitioning of potassium between silicates and sulphide melts - Experiments relevant to the earth's core.

    Science.gov (United States)

    Goettel, K. A.

    1972-01-01

    The partitioning of potassium between roedderite, K2Mg5Si12O30 and an Fe-FeS melt was investigated at temperatures about 40 C above the Fe-FeS eutectic. Roedderite was considered a prime candidate for one of the potassium-bearing phases in the primitive earth because roedderite and merrihueite are the only two silicates containing essential potassium which have been identified in stony meteorites. Application of the results to a primitive chondritic earth is discussed, and it is concluded that extraction of most of the earth's potassium into the Fe-FeS core would occur under the conditions in the early earth.-

  20. Globfit: Consistently fitting primitives by discovering global relations

    KAUST Repository

    Li, Yangyan

    2011-07-01

    Given a noisy and incomplete point set, we introduce a method that simultaneously recovers a set of locally fitted primitives along with their global mutual relations. We operate under the assumption that the data corresponds to a man-made engineering object consisting of basic primitives, possibly repeated and globally aligned under common relations. We introduce an algorithm to directly couple the local and global aspects of the problem. The local fit of the model is determined by how well the inferred model agrees to the observed data, while the global relations are iteratively learned and enforced through a constrained optimization. Starting with a set of initial RANSAC based locally fitted primitives, relations across the primitives such as orientation, placement, and equality are progressively learned and conformed to. In each stage, a set of feasible relations are extracted among the candidate relations, and then aligned to, while best fitting to the input data. The global coupling corrects the primitives obtained in the local RANSAC stage, and brings them to precise global alignment. We test the robustness of our algorithm on a range of synthesized and scanned data, with varying amounts of noise, outliers, and non-uniform sampling, and validate the results against ground truth, where available. © 2011 ACM.

  1. EARTH ROADS ARE EASY

    Directory of Open Access Journals (Sweden)

    David O. Whitten

    2000-01-01

    Full Text Available The earliest European immigrants in America traveled on waterways and on pathways worn into the earth by animals and Native Americans. Once their communities began to thrive, settlers widened paths and cleared new roads and streets then began experimenting with inexpensive surfacing to reduce dust in dry weather and mud in wet. “Earth Roads Are Easy” investigates materials and techniques used to maintain primitive thoroughfares with a minimum of effort and expense. The options range from the mundane—clay, sand, gravel, calcium chloride, oil, and tar—to the extraordinary—water glass, adobe clay, beet juice, and carpeting.There is no more dfficult problem confronting highway engineers than that of properly constructing and maintaining an earth road. The work may be less spectacular than the construction and maintenance of hard-surfaced roads, but there is greater latitude in location, methods of construction and choice of materials, consequently there is more scope for the exercise of sound judgment on the part of the engineer.1

  2. Giant vesicles "colonies": a model for primitive cell communities.

    Science.gov (United States)

    Carrara, Paolo; Stano, Pasquale; Luisi, Pier Luigi

    2012-07-09

    Current research on the origin of life typically focuses on the self-organisation of molecular components in individual cell-like compartments, thereby bringing about the emergence of self-sustaining minimal cells. This is justified by the fact that single cells are the minimal forms of life. No attempts have been made to investigate the cooperative mechanisms that could derive from the assembly of individual compartments. Here we present a novel experimental approach based on vesicles "colonies" as a model of primitive cell communities. Experiments show that several advantages could have favoured primitive cell colonies when compared with isolated primitive cells. In fact there are two novel unexpected features typical of vesicle colonies, namely solute capture and vesicle fusion, which can be seen as the basic physicochemical mechanisms at the origin of life.

  3. Intramedullary spinal cord primitive neuroectodermal tumor presenting with hydrocephalus.

    Science.gov (United States)

    Alexiou, George A; Siozos, George; Stefanaki, Kalliopi; Moschovi, Maria; Prodromou, Neofytos

    2013-02-01

    Spinal primitive neuroectodermal tumors are exceedingly rare. Herewith, we present the first case of an intramedullary spinal cord tumor associated with hydrocephalus in a 2-month-old boy that presented with left hemiparesis. The patient had been diagnosed on prenatal ultrasound with enlarged ventricular system. At his current admission, a brain magnetic resonance imaging (MRI) revealed hydrocephalus and an intramedullary lesion extending from the second cervical to the first thoracic vertebrae. Dissemination of the tumor was revealed intracranially and in the spinal canal. After a ventriculoperitoneal shunt placement a radical resection of the tumor was performed, however some small tumor remnants could not be safely removed. Postoperative there was no neurologic deterioration. The tumor was diagnosed as a central nervous system primitive neuroectodermal tumor (World Health Organization grade IV). Spinal intramedullary primitive neuroectodermal tumors are extremely rare. In such rare tumors, multiinstitutional studies are needed for treatment guidelines to be established.

  4. Clay minerals in primitive meteorites and interplanetary dust 1

    Science.gov (United States)

    Zolensky, M. E.; Keller, L. P.

    1991-01-01

    Many meteorites and interplanetary dust particles (IDPs) with primitive compositions contain significant amounts of phyllosilicate minerals, which are generally interpreted as evidence of protoplanetary aqueous alteration at an early period of the solar system. These meteorites are chondrites (near solar composition) of the carbonaceous and ordinary varieties. The former are subdivided (according to bulk composition and petrology) into CI, CM, CV, CO, CR, and ungrouped classes. IDPs are extraterrestrial particulates, collected in stratosphere, which have chemical compositions indicative of a primitive origin; they are typically distinct from the primitive meteorites. Characterization of phyllosilicates in these materials is a high priority because of the important physico-chemical information they hold. The most common phyllosilicates present in chondritic extraterrestrial materials are serpentine-group minerals, smectites, and micas. We discuss these phyllosilicates and describe the interpretation of their occurrence in meteorites and IDPs and what this indicates about history of their parent bodies, which are probably the hydrous asteroids.

  5. The humerus of Aegyptopithecus zeuxis: a primitive anthropoid.

    Science.gov (United States)

    Fleagle, J G; Simons, E L

    1982-10-01

    Two complete humeri of Aegyptopithecus zeuxis have been recovered from Oligocene deposits in the Fayum Province of Egypt. These new specimens support previous interpretations of the locomotor adaptations of this species and indicate that A. zeuxis was a robust, slowly moving arboreal quadruped. While the previously described distal articular region of the humerus is virtually identical with the same region in many extant ceboids and the Miocene hominoid Pliopithecus vindobonensis, the more proximal parts of the humerus show many primitive "prosimianlike" features not found the limbs of extant anthropoids. The primitive features include the absence of a distinct deltoid plane, a broad shallow bicipital groove, a large brachialis flange, and an entepicondylar foramen. In most features, the humerus of Aegyptopithecus zeuxis is more primitive than the hypothetical last common ancestor of extant cercopithecoids and hominoids based on neontological comparisons. This supports other lines of evidence indicating that the hominoids from the Egyptian Oligocene are morphologically ancestral to both Old World monkeys and apes.

  6. Deep Interior: Probing the Structure of Primitive Bodies

    Science.gov (United States)

    Asphaug, Erik; Scheeres, Daniel; Safaeinili, Ali

    probe the mechanical behavior of an asteroid we conclude each rendezvous by observing one or more explosion cratering experiments. Cratering (CRT). Cratering is the primary mode of geologic evolution of asteroids, and meteoroid impacts can trigger outbursts on cometary nuclei. The process is important to study for its own sake, and a cratering experiment offers three additional science benefits: (1) final crater diameter and morphology indicates the mechanical behavior of regolith and other exterior materials; (2) cratering exposes the subsurface for analysis of interior materials; and (3) cratering might trigger global reverberations that can be detected using before-and-after image comparisons of toppled boulders and landslides. Small cratering events may be of global consequence on small asteroids (Asphaug, MAPS, in press) and thus a grenade of only a few kg is likely to send a detectable resurfacing reverberation spanning the asteroid. This experiment thus serves as a low cost proxy for primitive body seismology. Global seismic response is quantified using techniques that have been developed on Earth based on estimates for the dynamical acceleration of preciariously balanced rocks (Brune et al., JGR 2003). Ideally the mission would have two cratering charges per rendezvous target, differing by ˜2 orders of magnitude in yield, to bracket local to global response. Cratering and landslide physics will also be studied in this novel microgravity setting, for the purpose of establishing scaling rules and addressing fundamental problems of dense granular flow. Moreover, many cubic meters of ejected regolith are exposed for analysis of size distribution, clast shape, spectral heterogeneity, and dynamics. In the case that the asteroid is metastable (e.g. a rapid rotator), the small cratering event might trigger a global avalanche, in which case Deep Interior will observe the formation of transitory debris disks or small moons (e.g. Scheeres et al., Science 2007). Hazards to

  7. The Utility of Cognitive Plausibility in Language Acquisition Modeling: Evidence From Word Segmentation

    National Research Council Canada - National Science Library

    Phillips, Lawrence; Pearl, Lisa

    2015-01-01

    The informativity of a computational model of language acquisition is directly related to how closely it approximates the actual acquisition task, sometimes referred to as the model's cognitive plausibility...

  8. Choosing diverse sets of plausible scenarios in multidimensional exploratory futures techniques

    NARCIS (Netherlands)

    Lord, Steven; Helfgott, Ariella; Vervoort, Joost M.

    2016-01-01

    Abstract Morphological analysis allows any number of dimensions to be retained when framing future conditions, and techniques within morphological analysis determine which combinations of those dimensions represent plausible futures. However, even a relatively low number of dimensions in future cond

  9. Context of culture: Critique of the primitive mind

    Directory of Open Access Journals (Sweden)

    Božilović Nikola

    2010-01-01

    Full Text Available The author of this paper has the intention to reach the new meaning and sense of the primitive mentality by analyzing it in early social communities. He also wants to point out the possible reflections of the spirit and consciousness of our ancestors on us, here and now. The first part of the paper is dedicated to a critical deliberation on anthropological conflicts which have arisen concerning the reasoning power of the so-called primitives. The crucial question lies in the following: Is the difference between the “primitive” and the “civilized” mentality fundamental or is it possible only to a certain degree. The author takes the notion of primitive mentality through time and points to the medieval understandings, which are occupied by teratological themes, then to the renaissance comprehension, which relies on the first experiential observations, and, finally, to the enlightenment ideas of exotic peoples out of which the myth of “the good savage” is born. The nineteenth and twentieth centuries introduce the notions of “people’s character” and “national spirit”. The opinions are polarized, on the one hand of ethnocentrism, carried by the prejudice of people and ethnic groups and, on the other hand, of cultural relativism, based on the understanding and appreciation of cultural differences. In the end, the author also recognizes the modern primitive man, one who is not ready to deal with the challenges of his age. The modern primitive recalls the spirits of the past, the surviving and anachronic models of behavior, unaware of the fact that these are the same models that he has ascribed to “savages”. However, while such thinking and acting was justified by the cultural level at which our ancestors had lived, the mental frame of the contemporary primitives is significantly in contrast with the high level of civilization development.

  10. Coordinating control of multiple rigid bodies based on motion primitives

    Institute of Scientific and Technical Information of China (English)

    Fan Wu; Zhi-Yong Geng

    2012-01-01

    This paper studies the problem of coordinated motion generation for a group of rigid bodies.Two classes of coordinated motion primitives,relative equilibria and maneuvers,are given as building blocks for generating coordinated motions.In a motion-primitive based planning framework,a control method is proposed for the robust execution of a coordinated motion plan in the presence of perturbations,The control method combines the relative equilibria stabilization with maneuver design,and results in a closeloop motion planning framework.The performance of the control method has been illustrated through a numerical simulation.

  11. Replicating vesicles as models of primitive cell growth and division.

    Science.gov (United States)

    Hanczyc, Martin M; Szostak, Jack W

    2004-12-01

    Primitive cells, lacking the complex bio-machinery present in modern cells, would have had to rely on the self-organizing properties of their components and on interactions with their environment to achieve basic cellular functions such as growth and division. Many bilayer-membrane vesicles, depending on their composition and environment, can exhibit complex morphological changes such as growth, fusion, fission, budding, internal vesicle assembly and vesicle-surface interactions. The rich dynamic properties of these vesicles provide interesting models of how primitive cellular replication might have occurred in response to purely physical and chemical forces.

  12. A primitive-based 3D object recognition system

    Science.gov (United States)

    Dhawan, Atam P.

    1988-01-01

    An intermediate-level knowledge-based system for decomposing segmented data into three-dimensional primitives was developed to create an approximate three-dimensional description of the real world scene from a single two-dimensional perspective view. A knowledge-based approach was also developed for high-level primitive-based matching of three-dimensional objects. Both the intermediate-level decomposition and the high-level interpretation are based on the structural and relational matching; moreover, they are implemented in a frame-based environment.

  13. Primary spinal primitive neuroectodermal tumor on MR imaging

    Directory of Open Access Journals (Sweden)

    Prashant J Thoriya

    2015-01-01

    Full Text Available Neoplasms in the region of filum terminale are not uncommon. Myxopapillary ependymoma is the commonest tumor at this location. The differentials reported for this entity are nerve sheath tumor, meningioma, paraganglioma, intradural metastases, lymphoma, other varieties of ependymoma, subependymoma, astrocytoma, ganglioglioma, hemangioblastoma, and primitive neuroectodermal tumor (PNET. PNET may very rarely present as an intradural thoracolumbar mass. We present pre- and post-therapy magnetic resonance imaging (MRI features of a patient with proven primary spinal primitive neuroectodermal tumor (PSPNET of peripheral subtype.

  14. Letters of Gold: Enabling Primitive Accumulation through Neoliberal Conservation

    OpenAIRE

    Büscher, Bram

    2009-01-01

    textabstractAbstract: In Capital I, Marx wrote that the history of the separation of the producers from the means of production “is written in the annals of mankind in letters of blood and fire” (Marx, 1976: 875). This ‘so-called primitive accumulation’, or ‘accumulation by dispossession’ in David Harvey’s words, continues unabated. Yet, its framing has changed considerably. Increasingly, capitalists have tried to avoid writing primitive accumulation in ‘letters of blood and fire’. Instead, t...

  15. Primitive chest wall neuroectodermal tumor in a pediatric patient.

    Science.gov (United States)

    Liu, Zhengcheng; Zou, Wei; Ma, Guodong; Pan, Yanqing

    2011-10-01

    A 13-year-old boy with a primitive neuroectodermal tumor of the chest wall is presented. After four cycles of chemotherapy, a computed tomography scan of his chest showed a larger mass invading the left upper lobe of the lung. He underwent resection of the left chest wall from the left fourth to sixth ribs, including the tumor, combined with left upper lobectomy and lymph node dissection. A diagnosis of primitive neuroectodermal tumor was confirmed histopathologically and immunohistochemically. After surgery, four cycles of chemotherapy with ifosfamide and etoposide were given. One year after treatment, the patient is currently doing well without evidence of recurrence.

  16. Endobronchial Primitive Neuroectodermal Tumor With Pneumothorax Ex Vacuo.

    Science.gov (United States)

    Han, Wongyeong; Huh, Dongmyung; Kim, Byoungho; Kwak, Eunkyoung; Lee, Sunah

    2015-10-01

    We experienced a rare case of an endobronchial primitive neuroectodermal tumor of the left main bronchus. Initially we suspected pneumothorax caused by a collapsed left upper lobe and an air-entrapped lower lobe. After tube thoracostomy, the pneumothorax persisted without air leakage. A tumor was detected at the left main bronchus on computed tomography and bronchoscopy, and diagnosed pathologically as small cell lung cancer. Under the presumed diagnosis of limited-stage small cell lung cancer, we performed a left pneumonectomy. The tumor was eventually identified pathologically as a primitive neuroectodermal tumor. Although adjuvant chemoradiotherapy was not performed, no recurrence was observed.

  17. Primitive neuroectodermal tumor of lumbar spine: case report

    Institute of Scientific and Technical Information of China (English)

    HE Shi-sheng; ZHAO Jie; HAN Kai-wei; HOU Tie-sheng; Nazakat Hussain; ZHANG Shun-ming

    2007-01-01

    @@ Primitive neuroectodermal tumors (PNETs), derived from the primitive neural crest, are highly malignant and mainly exist in the central nervous system (CNS),chest wall, lower extremities, trunk, kidney, and orbit but rarely in the spine. Though multidisciplinary treatments have been well established as the standard therapy for intracranial PNETs, little is known about the optimal treatment strategy and therapeutic results for intraspinal PNETs. The following report illustrates the operative and non-operative management of an extradural PNET at the level of L5 in a young girl.

  18. Childhood pheochromocytoma in a survivor of central primitive neuroectodermal tumor.

    Science.gov (United States)

    Nakano, Yoshiko; Fujimaru, Rika; Ishii, Keiichi; Sakamoto, Hiroaki; Inoue, Takeshi; Sako, Masahiro; Yamada, Hiroshi

    2013-08-01

    Pheochromocytoma and central nervous system primitive neuroectodermal tumor are both neural crest-derived tumors. The former is usually benign and develops mainly in adulthood and the latter brain tumor mainly occurs in childhood and has a poor prognosis. We report a case of a 15-year-old boy who developed pheochromocytoma after more than 10 years of complete remission of central primitive neuroectodermal tumor. Thus far, there have been no reports of childhood cancer survivors who developed pheochromocytoma. This quite rare occurrence of two tumors in a single patient may imply some unidentified linkage or common genetic background.

  19. Search for primitive matter in the Solar System

    Science.gov (United States)

    Libourel, Guy; Michel, Patrick; Delbo, Marco; Ganino, Clément; Recio-Blanco, Alejandra; de Laverny, Patrick; Zolensky, Michael E.; Krot, Alexander N.

    2017-01-01

    In this note, we show that neither the age of an object, nor its mineralogy is discriminant enough for revealing its primitiveness, and propose a new parameterization scheme based on the processes the matter underwent since its delivery to the Solar System. By ranking celestial objects and their constituents, two antagonistic sources of primitive materials in the protoplanetary disk emerge, one close to the Sun resulting from evaporation, condensation and melting of the protosolar molecular cloud dust followed by accretion into asteroidal bodies, and the other at large heliocentric distances resulting from agglomeration of the protosolar and solar dust into cometary bodies, the latter reservoir remaining poorly sampled so far.

  20. Interstellar chemistry recorded in organic matter from primitive meteorites.

    Science.gov (United States)

    Busemann, Henner; Young, Andrea F; Alexander, Conel M O'd; Hoppe, Peter; Mukhopadhyay, Sujoy; Nittler, Larry R

    2006-05-05

    Organic matter in extraterrestrial materials has isotopic anomalies in hydrogen and nitrogen that suggest an origin in the presolar molecular cloud or perhaps in the protoplanetary disk. Interplanetary dust particles are generally regarded as the most primitive solar system matter available, in part because until recently they exhibited the most extreme isotope anomalies. However, we show that hydrogen and nitrogen isotopic compositions in carbonaceous chondrite organic matter reach and even exceed those found in interplanetary dust particles. Hence, both meteorites (originating from the asteroid belt) and interplanetary dust particles (possibly from comets) preserve primitive organics that were a component of the original building blocks of the solar system.

  1. The Utility of Cognitive Plausibility in Language Acquisition Modeling: Evidence From Word Segmentation.

    Science.gov (United States)

    Phillips, Lawrence; Pearl, Lisa

    2015-11-01

    The informativity of a computational model of language acquisition is directly related to how closely it approximates the actual acquisition task, sometimes referred to as the model's cognitive plausibility. We suggest that though every computational model necessarily idealizes the modeled task, an informative language acquisition model can aim to be cognitively plausible in multiple ways. We discuss these cognitive plausibility checkpoints generally and then apply them to a case study in word segmentation, investigating a promising Bayesian segmentation strategy. We incorporate cognitive plausibility by using an age-appropriate unit of perceptual representation, evaluating the model output in terms of its utility, and incorporating cognitive constraints into the inference process. Our more cognitively plausible model shows a beneficial effect of cognitive constraints on segmentation performance. One interpretation of this effect is as a synergy between the naive theories of language structure that infants may have and the cognitive constraints that limit the fidelity of their inference processes, where less accurate inference approximations are better when the underlying assumptions about how words are generated are less accurate. More generally, these results highlight the utility of incorporating cognitive plausibility more fully into computational models of language acquisition.

  2. Using critical evaluation to reappraise plausibility judgments: A critical cognitive component of conceptual change

    Science.gov (United States)

    Lombardi, D.

    2011-12-01

    Plausibility judgments-although well represented in conceptual change theories (see, for example, Chi, 2005; diSessa, 1993; Dole & Sinatra, 1998; Posner et al., 1982)-have received little empirical attention until our recent work investigating teachers' and students' understanding of and perceptions about human-induced climate change (Lombardi & Sinatra, 2010, 2011). In our first study with undergraduate students, we found that greater plausibility perceptions of human-induced climate accounted for significantly greater understanding of weather and climate distinctions after instruction, even after accounting for students' prior knowledge (Lombardi & Sinatra, 2010). In a follow-up study with inservice science and preservice elementary teachers, we showed that anger about the topic of climate change and teaching about climate change was significantly related to implausible perceptions about human-induced climate change (Lombardi & Sinatra, 2011). Results from our recent studies helped to inform our development of a model of the role of plausibility judgments in conceptual change situations. The model applies to situations involving cognitive dissonance, where background knowledge conflicts with an incoming message. In such situations, we define plausibility as a judgment on the relative potential truthfulness of incoming information compared to one's existing mental representations (Rescher, 1976). Students may not consciously think when making plausibility judgments, expending only minimal mental effort in what is referred to as an automatic cognitive process (Stanovich, 2009). However, well-designed instruction could facilitate students' reappraisal of plausibility judgments in more effortful and conscious cognitive processing. Critical evaluation specifically may be one effective method to promote plausibility reappraisal in a classroom setting (Lombardi & Sinatra, in progress). In science education, critical evaluation involves the analysis of how evidentiary

  3. Redox-induced lower mantle density contrast and effect on mantle structure and primitive oxygen

    Science.gov (United States)

    Gu, Tingting; Li, Mingming; McCammon, Catherine; Lee, Kanani K. M.

    2016-09-01

    The mantle comprises nearly three-quarters of Earth's volume and through convection connects the deep interior with the lithosphere and atmosphere. The composition of the mantle determines volcanic emissions, which are intimately linked to evolution of the primitive atmosphere. Fundamental questions remain on how and when the proto-Earth mantle became oxidized, and whether redox state is homogeneous or developed large-scale structures. Here we present experiments in which we subjected two synthetic samples of nearly identical composition that are representative of the lower mantle (enstatite chondrite), but synthesized under different oxygen fugacities, to pressures and temperatures up to 90 GPa and 2,400 K. In addition to the mineral bridgmanite, compression of the more reduced material also produced Al2O3 as a separate phase, and the resulting assemblage is about 1 to 1.5% denser than in experiments with the more oxidized material. Our geodynamic simulations suggest that such a density difference can cause a rapid ascent and accumulation of oxidized material in the upper mantle, with descent of the denser reduced material to the core-mantle boundary. We suggest that the resulting heterogeneous redox conditions in Earth's interior can contribute to the large low-shear velocity provinces in the lower mantle and the evolution of atmospheric oxygen.

  4. Action Recognition in Semi-synthetic Images using Motion Primitives

    DEFF Research Database (Denmark)

    Fihl, Preben; Holte, Michael Boelstoft; Moeslund, Thomas B.

    This technical report describes an action recognition approach based on motion primitives. A few characteristic time instances are found in a sequence containing an action and the action is classified from these instances. The characteristic instances are defined solely on the human motion, hence...

  5. A Test of Durkheim's Theory of Suicide in Primitive Societies.

    Science.gov (United States)

    Lester, David

    1992-01-01

    Classified primitive societies as high, moderate, or low on independent measures of social integration and social regulation to test Durkheim's theory of suicide. Estimated frequency of suicide did not differ between those societies predicted to have high, moderate, and low suicide rates. Durkheim's theory was not confirmed. (Author/NB)

  6. On Primitive Elements in Finite Fields and on Elliptic Curves

    Science.gov (United States)

    Shparlinskiĭ, I. E.

    1992-02-01

    An asymptotic formula for the number of primitive polynomials of the form f (x) + a, a = 1, ..., h, where f (x)inFp[x], is obtained, "on the average" over all polynomials f of fixed degree, and an estimate for the number of "sparse" factorable polynomials is also obtained.

  7. Addressing Nature Deficit Disorder through Primitive Camping Experiences

    Science.gov (United States)

    Allen, Kevin; Varner, Keegan; Sallee, Jeff

    2011-01-01

    Today's youth suffer from Nature Deficit Disorder, a condition that has been connected to ADHD, shortage of creativity, and general lack of knowledge about the outdoors. A team of educators and specialists are addressing this issue with primitive camping. County educators were trained using experiential learning and train-the-trainer techniques.…

  8. Primary Primitive Neuroectodermal Tumor of the Breast: a Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Ko, Kyung Ran; Kim, Eun Ah; Kwon, Young Mee [Hospital and Research Institute, National Cancer Center, Goyang (Korea, Republic of); Lee, Eun Sook [Korea University, Seoul (Korea, Republic of)

    2009-08-15

    Primary primitive neuroectodermal tumors (PNET) are rare malignant tumors, affecting mostly children and adolescents. Only three cases of primary breast PNETs have been reported in the medical literature, with none in Korea. We present a case of a primary PNET of the breast in a 33-year-old woman, with imaging and immunohistopathology findings.

  9. Primary extraskeletal Ewing's sarcoma/primitive neuroectodermal tumor of breast

    Directory of Open Access Journals (Sweden)

    Smita Srivastava

    2016-01-01

    Full Text Available Extraskeletal Ewing's sarcoma (EES is a rare soft tissue tumor that is morphologically indistinguishable from skeletal ES. We report a case of a 25-year-old female with recurrent EES/primitive neuroectodermal tumor of right breast with imaging findings on mammogram, ultrasound, magnetic resonance imaging breast, and positron emission tomography–computed tomography.

  10. Action Recognition Using Motion Primitives and Probabilistic Edit Distance

    DEFF Research Database (Denmark)

    Fihl, Preben; Holte, Michael Boelstoft; Moeslund, Thomas B.;

    2006-01-01

    instances. The human whereabouts at these instances are extracted by double difference images and represented by four features. In each frame the primitive, if any, that best explains the observed data is identified. This leads to a discrete recognition problem since a video sequence will be converted...

  11. Letters of Gold: Enabling Primitive Accumulation through Neoliberal Conservation

    NARCIS (Netherlands)

    B.E. Büscher (Bram)

    2009-01-01

    textabstractAbstract: In Capital I, Marx wrote that the history of the separation of the producers from the means of production “is written in the annals of mankind in letters of blood and fire” (Marx, 1976: 875). This ‘so-called primitive accumulation’, or ‘accumulation by dispossession’ in David H

  12. Architecting as Decision Making with Patterns and Primitives

    NARCIS (Netherlands)

    Zdun, Uwe; Avgeriou, Paris; Hentrich, Carsten; Dustdar, Schahram

    2008-01-01

    The application of patterns is used as a foundation for many central design decisions in software architecture, but because of the informal nature of patterns, these design decisions are usually not precisely documented in the models. In our earlier work, we had proposed pattern primitives as a

  13. A Test of Durkheim's Theory of Suicide in Primitive Societies.

    Science.gov (United States)

    Lester, David

    1992-01-01

    Classified primitive societies as high, moderate, or low on independent measures of social integration and social regulation to test Durkheim's theory of suicide. Estimated frequency of suicide did not differ between those societies predicted to have high, moderate, and low suicide rates. Durkheim's theory was not confirmed. (Author/NB)

  14. Understanding and determining the variability of the primitive stress environment.

    CSIR Research Space (South Africa)

    Sellers, EJ

    2002-10-01

    Full Text Available The primitive stress state is an important input into the design of underground excavations. However, it is well known that the stress state varies considerably from place to place. The aim of this project was to determine the main causes...

  15. Interactions between visual and motor areas during the recognition of plausible actions as revealed by magnetoencephalography.

    Science.gov (United States)

    Pavlidou, Anastasia; Schnitzler, Alfons; Lange, Joachim

    2014-02-01

    Several studies have shown activation of the mirror neuron system (MNS), comprising the temporal, posterior parietal, and sensorimotor areas when observing plausible actions, but far less is known on how these cortical areas interact during the recognition of a plausible action. Here, we recorded neural activity with magnetoencephalography while subjects viewed point-light displays of biologically plausible and scrambled versions of actions. We were interested in modulations of oscillatory activity and, specifically, in coupling of oscillatory activity between visual and motor areas. Both plausible and scrambled actions elicited modulations of θ (5-7 Hz), α (7-13 Hz), β (13-35 Hz), and γ (55-100 Hz) power within visual and motor areas. When comparing between the two actions, we observed sequential and spatially distinct increases of γ (∼65 Hz), β (∼25 Hz), and α (∼11 Hz) power between 0.5 and 1.3 s in parieto-occipital, sensorimotor, and left temporal areas. In addition, significant clusters of γ (∼65 Hz) and α/β (∼15 Hz) power decrease were observed in right temporal and parieto-occipital areas between 1.3 and 2.0 s. We found β-power in sensorimotor areas to be positively correlated on a trial-by-trial basis with parieto-occipital γ and left temporal α-power for the plausible but not for the scrambled condition. These results provide new insights in the neuronal oscillatory activity of the areas involved in the recognition of plausible action movements and their interaction. The power correlations between specific areas underscore the importance of interactions between visual and motor areas of the MNS during the recognition of a plausible action.

  16. A primitive fish from the Cambrian of North America.

    Science.gov (United States)

    Morris, Simon Conway; Caron, Jean-Bernard

    2014-08-28

    Knowledge of the early evolution of fish largely depends on soft-bodied material from the Lower (Series 2) Cambrian period of South China. Owing to the rarity of some of these forms and a general lack of comparative material from other deposits, interpretations of various features remain controversial, as do their wider relationships amongst post-Cambrian early un-skeletonized jawless vertebrates. Here we redescribe Metaspriggina on the basis of new material from the Burgess Shale and exceptionally preserved material collected near Marble Canyon, British Columbia, and three other Cambrian Burgess Shale-type deposits from Laurentia. This primitive fish displays unambiguous vertebrate features: a notochord, a pair of prominent camera-type eyes, paired nasal sacs, possible cranium and arcualia, W-shaped myomeres, and a post-anal tail. A striking feature is the branchial area with an array of bipartite bars. Apart from the anterior-most bar, which appears to be slightly thicker, each is associated with externally located gills, possibly housed in pouches. Phylogenetic analysis places Metaspriggina as a basal vertebrate, apparently close to the Chengjiang taxa Haikouichthys and Myllokunmingia, demonstrating also that this primitive group of fish was cosmopolitan during Lower-Middle Cambrian times (Series 2-3). However, the arrangement of the branchial region in Metaspriggina has wider implications for reconstructing the morphology of the primitive vertebrate. Each bipartite bar is identified as being respectively equivalent to an epibranchial and ceratobranchial. This configuration suggests that a bipartite arrangement is primitive and reinforces the view that the branchial basket of lampreys is probably derived. Other features of Metaspriggina, including the external position of the gills and possible absence of a gill opposite the more robust anterior-most bar, are characteristic of gnathostomes and so may be primitive within vertebrates.

  17. Expanding earth

    Energy Technology Data Exchange (ETDEWEB)

    Carey, S.W.

    1976-01-01

    Arguments in favor of an expanding earth are presented. The author believes that the theory of plate tectonics is a classic error in the history of geology. The case for the expanding earth is organized in the following way: introductory review - face of the earth, development of expanding earth concept, necessity for expansion, the subduction myth, and definitions; some principles - scale of tectonic phenomena, non-uniformitarianism, tectonic profile, paleomagnetism, asymmetry of the earth, rotation of the earth, and modes of crustal extension; regional studies - western North America, Central America, South-East Asia, and the rift oceans; tests and cause of expansion. 824 references, 197 figures, 11 tables. (RWR)

  18. New Clues to Beginnings of Life on Earth

    Science.gov (United States)

    Chemical and Engineering News, 1974

    1974-01-01

    Describes current experiments that help to explain chemical processes which probably existed prior to the first living cells. Some experiments suggest that a significant portion of a major metabolic pathway, the Krebs cycle, may have developed in the earth's primitive atmosphere to be later incorporated into living organisms. (JR)

  19. Stereotyping to infer group membership creates plausible deniability for prejudice-based aggression.

    Science.gov (United States)

    Cox, William T L; Devine, Patricia G

    2014-02-01

    In the present study, participants administered painful electric shocks to an unseen male opponent who was either explicitly labeled as gay or stereotypically implied to be gay. Identifying the opponent with a gay-stereotypic attribute produced a situation in which the target's group status was privately inferred but plausibly deniable to others. To test the plausible deniability hypothesis, we examined aggression levels as a function of internal (personal) and external (social) motivation to respond without prejudice. Whether plausible deniability was present or absent, participants high in internal motivation aggressed at low levels, and participants low in both internal and external motivation aggressed at high levels. The behavior of participants low in internal and high in external motivation, however, depended on experimental condition. They aggressed at low levels when observers could plausibly attribute their behavior to prejudice and aggressed at high levels when the situation granted plausible deniability. This work has implications for both obstacles to and potential avenues for prejudice-reduction efforts.

  20. A new algorithm for computing primitive elements in GF q square

    Science.gov (United States)

    Reed, I. S.; Truong, T. K.; Miller, R. L.

    1978-01-01

    A new method is developed to find primitive elements in the Galois field of sq q elements GF(sqq), where q is a Mersenne prime. Such primitive elements are needed to implement transforms over GF(sq q).

  1. A new algorithm for computing primitive elements in GF q square

    Science.gov (United States)

    Reed, I. S.; Truong, T. K.; Miller, R. L.

    1978-01-01

    A new method is developed to find primitive elements in the Galois field of sq q elements GF(sqq), where q is a Mersenne prime. Such primitive elements are needed to implement transforms over GF(sq q).

  2. Primitive neuroectodermal tumor of the orbit in a 5-year-old girl with microphthalmia

    DEFF Research Database (Denmark)

    Alyahya, Ghassan Ayish Jabur; Heegaard, Steffen; Fledelius, Hans C.;

    2000-01-01

    ophthalmology, primitive neuroectodermal tumor (PNET), Ewing's sarcoma, small round-cell tumors, retinoblastoma, medulloepithelioma, microphthalmia, orbitotomy......ophthalmology, primitive neuroectodermal tumor (PNET), Ewing's sarcoma, small round-cell tumors, retinoblastoma, medulloepithelioma, microphthalmia, orbitotomy...

  3. Don't Plan for the Unexpected: Planning Based on Plausibility Models

    DEFF Research Database (Denmark)

    Andersen, Mikkel Birkegaard; Bolander, Thomas; Jensen, Martin Holm

    2015-01-01

    We present a framework for automated planning based on plausibility models, as well as algorithms for computing plans in this framework. Our plausibility models include postconditions, as ontic effects are essential for most planning purposes. The framework presented extends a previously developed...... framework based on dynamic epistemic logic (DEL), without plausibilities/beliefs. In the pure epistemic framework, one can distinguish between strong and weak epistemic plans for achieving some, possibly epistemic, goal. By taking all possible outcomes of actions into account, a strong plan guarantees...... that the agent achieves this goal. Conversely, a weak plan promises only the possibility of leading to the goal. In real-life planning scenarios where the planning agent is faced with a high degree of uncertainty and an almost endless number of possible exogenous events, strong epistemic planning...

  4. Inference and Plausible Reasoning in a Natural Language Understanding System Based on Object-Oriented Semantics

    CERN Document Server

    Ostapov, Yuriy

    2012-01-01

    Algorithms of inference in a computer system oriented to input and semantic processing of text information are presented. Such inference is necessary for logical questions when the direct comparison of objects from a question and database can not give a result. The following classes of problems are considered: a check of hypotheses for persons and non-typical actions, the determination of persons and circumstances for non-typical actions, planning actions, the determination of event cause and state of persons. To form an answer both deduction and plausible reasoning are used. As a knowledge domain under consideration is social behavior of persons, plausible reasoning is based on laws of social psychology. Proposed algorithms of inference and plausible reasoning can be realized in computer systems closely connected with text processing (criminology, operation of business, medicine, document systems).

  5. Biologically plausible and evidence-based risk intervals in immunization safety research.

    Science.gov (United States)

    Rowhani-Rahbar, Ali; Klein, Nicola P; Dekker, Cornelia L; Edwards, Kathryn M; Marchant, Colin D; Vellozzi, Claudia; Fireman, Bruce; Sejvar, James J; Halsey, Neal A; Baxter, Roger

    2012-12-17

    In immunization safety research, individuals are considered at risk for the development of certain adverse events following immunization (AEFI) within a specific period of time referred to as the risk interval. These intervals should ideally be determined based on biologic plausibility considering features of the AEFI, presumed or known pathologic mechanism, and the vaccine. Misspecification of the length and timing of these intervals may result in introducing bias in epidemiologic and clinical studies of immunization safety. To date, little work has been done to formally assess and determine biologically plausible and evidence-based risk intervals in immunization safety research. In this report, we present a systematic process to define biologically plausible and evidence-based risk interval estimates for two specific AEFIs, febrile seizures and acute disseminated encephalomyelitis. In addition, we review methodologic issues related to the determination of risk intervals for consideration in future studies of immunization safety.

  6. The semiosis of prayer and the creation of plausible fictional worlds

    Directory of Open Access Journals (Sweden)

    J. Peter Södergård

    1999-01-01

    Full Text Available Prayer and incantation can perhaps be said to be 'mechanisms' that promise that lack will be liquidated and that there is an unlimited signator, a father, or some other metaphysical creature, standing behind and legitimizing the discourse. A way of communicating with the Unlimited that is privileged by an interpretive community that read the prayers aloud and enacted the magical stage-scripts. These highly overlapping categories function as one of the most common subforms of religious discourse for the creation, actualization and maintenance of plausible fictional worlds. They are liminal and transitional mechanisms that manipulate an empirical reader to phase-shift from an actual world to a plausible, by being inscribed in a possible and fictional world, thus creating a model reader, that perceives and acts according to the plausible world outlined by a given interpretive community, and that hears god talking in voces magicae and in god-speaking silence.

  7. Don't Plan for the Unexpected: Planning Based on Plausibility Models

    DEFF Research Database (Denmark)

    Andersen, Mikkel Birkegaard; Bolander, Thomas; Jensen, Martin Holm

    2015-01-01

    that the agent achieves this goal. Conversely, a weak plan promises only the possibility of leading to the goal. In real-life planning scenarios where the planning agent is faced with a high degree of uncertainty and an almost endless number of possible exogenous events, strong epistemic planning......We present a framework for automated planning based on plausibility models, as well as algorithms for computing plans in this framework. Our plausibility models include postconditions, as ontic effects are essential for most planning purposes. The framework presented extends a previously developed...... framework based on dynamic epistemic logic (DEL), without plausibilities/beliefs. In the pure epistemic framework, one can distinguish between strong and weak epistemic plans for achieving some, possibly epistemic, goal. By taking all possible outcomes of actions into account, a strong plan guarantees...

  8. An estimation-based approach for range image segmentation: on the reliability of primitive extraction

    NARCIS (Netherlands)

    Wang, Guoyu; Houkes, Zweitze; Ji, Guangrong; Zheng, Bing; Li, Xin

    2003-01-01

    This paper presents a new algorithm for estimation-based range image segmentation. Aiming at surface-primitive extraction from range data, we focus on the reliability of the primitive representation in the process of region estimation. We introduce an optimal description of surface primitives, by wh

  9. On the least primitive root in number fields

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Let K be an algebraic number field and OK its ring of integers.For any prime ideal p,the group(OK/p) of the reduced residue classes of integers is cyclic.We call any element of a generator of the group(OK/p) a primitive root modulo p.Stimulated both by Shoup’s bound for the rational improvement and Wang and Bauer’s generalization of the conditional result of Wang Yuan in 1959,we give in this paper a new bound for the least primitive root modulo a prime ideal p under the Grand Riemann Hypothesis for algebraic number field.Our results can be viewed as either the improvement of the result of Wang and Bauer or the generalization of the result of Shoup.

  10. Collaboration between primitive cell membranes and soluble catalysts.

    Science.gov (United States)

    Adamala, Katarzyna P; Engelhart, Aaron E; Szostak, Jack W

    2016-03-21

    One widely held model of early life suggests primitive cells consisted of simple RNA-based catalysts within lipid compartments. One possible selective advantage conferred by an encapsulated catalyst is stabilization of the compartment, resulting from catalyst-promoted synthesis of key membrane components. Here we show model protocell vesicles containing an encapsulated enzyme that promotes the synthesis of simple fatty acid derivatives become stabilized to Mg(2+), which is required for ribozyme activity and RNA synthesis. Thus, protocells capable of such catalytic transformations would have enjoyed a selective advantage over other protocells in high Mg(2+) environments. The synthetic transformation requires both the catalyst and vesicles that solubilize the water-insoluble precursor lipid. We suggest that similar modified lipids could have played a key role in early life, and that primitive lipid membranes and encapsulated catalysts, such as ribozymes, may have acted in conjunction with each other, enabling otherwise-impossible chemical transformations within primordial cells.

  11. The Primitive Spectrum of a Basic Classical Lie Superalgebra

    Science.gov (United States)

    Coulembier, Kevin

    2016-12-01

    We prove Conjecture 5.7 in Coulembier and Musson (Math. J., arXiv:1409.2532), describing all inclusions between primitive ideals for the general linear superalgebra in terms of the {Ext1}-quiver of simple highest weight modules. For arbitrary basic classical Lie superalgebras, we formulate two types of Kazhdan-Lusztig quasi-orders on the dual of the Cartan subalgebra, where one corresponds to the above conjecture. Both orders can be seen as generalisations of the left Kazhdan-Lusztig order on Hecke algebras and are related to categorical braid group actions. We prove that the primitive spectrum is always described by one of the orders, obtaining for the first time a description of the inclusions. We also prove that the two orders are identical if category O admits `enough' abstract Kazhdan-Lusztig theories. In particular, they are identical for the general linear superalgebra, concluding the proof of the conjecture.

  12. Quantifying Mapping Orbit Performance in the Vicinity of Primitive Bodies

    Science.gov (United States)

    Pavlak, Thomas A.; Broschart, Stephen B.; Lantoine, Gregory

    2015-01-01

    Predicting and quantifying the capability of mapping orbits in the vicinity of primitive bodies is challenging given the complex orbit geometries that exist and the irregular shape of the bodies themselves. This paper employs various quantitative metrics to characterize the performance and relative effectiveness of various types of mapping orbits including terminator, quasi-terminator, hovering, pingpong, and conic-like trajectories. Metrics of interest include surface area coverage, lighting conditions, and the variety of viewing angles achieved. The metrics discussed in this investigation are intended to enable mission designers and project stakeholders to better characterize candidate mapping orbits during preliminary mission formulation activities.The goal of this investigation is to understand the trade space associated with carrying out remotesensing campaigns at small primitive bodies in the context of a robotic space mission. Specifically,this study seeks to understand the surface viewing geometries, ranges, etc. that are available fromseveral commonly proposed mapping orbits architectures.

  13. Primary renal primitive neuroectodermal tumor: A rare presentation

    Directory of Open Access Journals (Sweden)

    V Goel

    2015-01-01

    Full Text Available Primitive Neuroectodermal Tumor of the kidney is a rare entity. Very few cases of primary renal PNET have been reported to date. Most literature about rPNET is isolated case reports. We report a case of rPNET in a 39-year-old male with a pre-operative diagnosis of renal cell carcinoma with renal vein thrombosis. The patient underwent radical nephrectomy with thrombolectomy, and histopathological examination revealed a highly aggressive tumor composed of monotonous sheets of round cells. Tumor cells were positive for CD 99 and FLI-1, hence confirming the diagnosis of Primitive Neuroectodermal Tumor. Post-surgery, patient was given VAC/IE-based adjuvant chemotherapy. In view of highly aggressive nature of this tumor, prompt diagnosis and imparting effective chemotherapy regimen to the patient is required, and it is important to differentiate PNET from other small round-cell tumors because of different therapeutic approach.

  14. Primitive neuroectodermal tumor/Ewing sarcoma of the retina.

    Science.gov (United States)

    Grossniklaus, Hans E; Shehata, Bahig; Sorensen, Poul; Bergstrom, Chris; Hubbard, G Baker

    2012-07-01

    An 11-year-old boy underwent enucleation of his left eye for an intraocular tumor. Examination showed a small, round blue cell tumor arising in the peripheral retina near the ciliary body. Immunohistochemical stain results were positive for neuron-specific enolase, synaptophysin, cluster of differentiation 99 (CD99), Friend leukemia integration 1, and CD56. Ultrastructural findings included occasional intracytoplasmic dense core granules. Polymerase chain reaction of the tumor showed a Ewing sarcoma/Friend leukemia integration gene fusion product. The tumor was classified as a primitive neuroectodermal tumor/Ewing sarcoma of the retina and should be distinguished from retinoblastoma. To our knowledge, this is the first case of primary primitive neuroectodermal tumor of the retina.

  15. Formalizing the Relationship Between Commitment and Basic Cryptographic Primitives

    Directory of Open Access Journals (Sweden)

    S. Sree Vivek

    2016-11-01

    Full Text Available Signcryption is a cryptographic primitive which offers the functionality of both digital signature and encryption with lower combined computational cost. On the other hand, commitment scheme allows an entity to commit to a value, where the entity reveals the committed value later during a decommit phase. In this paper, we explore the connection between commitment schemes, public key encryption, digital signatures and signcryption. We establish formal relationship between commitment and the other primitives. Our main result is that we show signcryption can be used as a commitment scheme with appropriate security notions. We show that if the underlying signcryption scheme is IND-CCA2 secure, then the hiding property of the commitment scheme is satisfied. Similarly, we show that if the underlying signcryption scheme is unforgeable, then the relaxed biding property of the commitment scheme is satisfied. Moreover, we prove that if the underlying signcryption scheme is NM-CCA2, then the commitment scheme is non-malleable.

  16. Neoplastic meningitis as the presentation of occult primitive neuroectodermal tumors.

    Science.gov (United States)

    Jennings, M T; Slatkin, N; D'Angelo, M; Ketonen, L; Johnson, M D; Rosenblum, M; Creasy, J; Tulipan, N; Walker, R

    1993-10-01

    Seven children and young adults initially presented with subacute meningitis and/or increased intracranial pressure. The diagnosis of neoplastic meningitis secondary to a primitive neuroectodermal neoplasm was delayed by the absence of an obvious primary tumor. The neuroradiologic appearance was that of a basimeningeal infiltrative process, complicated by communicating hydrocephalus or "pseudotumor cerebri." Myelography was important in the diagnosis of disseminated meningeal malignancy in four cases. Cerebrospinal fluid cytologic diagnosis was insensitive but ultimately confirmed in five cases. All seven patients experienced progressive disease despite neuraxis radiotherapy and intensive chemotherapy; six have died. Systemic dissemination to bone and/or peritoneum occurred in three patients while on therapy. In two, a primary parenchymal brain or spinal cord tumor could not be identified at postmortem examination. The presentation of a primitive neuroectodermal tumor as subacute meningitis without an evident primary tumor heralds an aggressive and refractory neoplasm.

  17. Search for Primitive Matter in the Solar System

    Science.gov (United States)

    Libourel, G.; Michel, P.; Delbo, M.; Ganino, C.; Recio-Blanco, A.; de Laverny, P.; Zolensky, M. E.; Krot, A. N.

    2017-01-01

    Recent astronomical observations and theoretical modeling led to a consensus regarding the global scenario of the formation of young stellar objects (YSO) from a cold molecular cloud of interstellar dust (organics and minerals) and gas that, in some cases, leads to the formation of a planetary system. In the case of our Solar System, which has already evolved for approximately 4567 Ma, the quest is to access, through the investigation of planets, moons, cometary and asteroidal bodies, meteorites, micrometeorites, and interplanetary dust particles, the primitive material that contains the key information about the early Solar System processes and its evolution. However, laboratory analyses of extraterrestrial samples, astronomical observations and dynamical models of the Solar System evolution have not brought yet any conclusive evidence on the nature and location of primitive matter in the Solar System, preventing a clear understanding of its early stages.

  18. Aqueous alteration on main belt primitive asteroids: Results from visible spectroscopy

    Science.gov (United States)

    Fornasier, S.; Lantz, C.; Barucci, M. A.; Lazzarin, M.

    2014-05-01

    increases through the P → F → B → C → G asteroids, these last being widely aqueous altered, strengthening thus the results previously obtained by Vilas (Vilas, F. [1994]. Icarus 111, 456-467). Around 50% of the observed C-type asteroids show absorption feature in the visible range due to hydrated silicates, implying that more than ∼70% of them will have a 3 μm absorption band and thus hydrated minerals on their surfaces, based on correlations between those two absorptions (Howell, E.S. et al. [2011]. EPSC-DPS Joint Meeting 2011, vol. 6. Abstracts, 637). We find that the aqueous alteration process dominates in primitive asteroids located between 2.3 and 3.1 AU, that is at smaller heliocentric distances than previously suggested by Vilas et al. (Vilas, F., Hatch, E.C., Larson, S.M., Sawyer, S.R., Gaffey, M.J. [1993]. Icarus 102, 225-231). The percentage of hydrated asteroids is strongly correlated with their size. The aqueous alteration process is less effective for bodies smaller than 50 km, while it dominates in the 50-240 km sized primitive asteroids. No correlation is found between the aqueous alteration process and the asteroids albedo or orbital elements. Comparing the ∼0.7 μm band parameters of hydrated silicates and CM2 carbonaceous chondrites, the meteorites that have aqueous altered asteroids as parent bodies, we see that the band center of meteorites is at longer wavelengths than that of asteroids. This difference on center positions may be attributed to different minerals abundances, and to the fact that CM2 available on Earth might not be representative of the whole aqueous altered asteroids population.

  19. MOLECULAR (RE-)CLASSIFICATION OF CNS-PRIMITIVE NEUROECTODERMAL TUMORS

    OpenAIRE

    Kool, Marcel; Sturm, Dominik; Northcott, Paul A.; Jones, David T. W.; Korshunov, Andrey; Lichter, Peter; Pfister, Stefan

    2014-01-01

    BACKGROUND: According to the current WHO classification of CNS tumors, childhood CNS primitive neuro-ectodermal tumors (CNS-PNETs; WHO °IV) are poorly differentiated embryonal tumors with early onset and aggressive clinical behavior. Histological diagnosis can be complicated by morphological heterogeneity and divergent differentiation. Recent studies suggest the existence of molecular subgroups of CNS-PNETs sharing biological characteristics with other childhood CNS tumors. Here, we aimed at ...

  20. Transitions between Discrete and Rhythmic Primitives in a Unimanual Task

    Directory of Open Access Journals (Sweden)

    Dagmar eSternad

    2013-07-01

    Full Text Available Given the vast complexity of human actions and interactions with objects, we proposed that control of sensorimotor behavior may utilize dynamic primitives. However, greater computational simplicity may come at the cost of reduced versatility. Evidence for primitives may be garnered by revealing such limitations. This study tested subjects performing a sequence of progressively faster discrete movements, in order to stress the system. We hypothesized that the increasing pace would elicit a transition to rhythmic movements, assumed to be computationally and neurally more efficient. Abrupt transitions between the two types of movements would support the hypothesis that rhythmic and discrete movements are distinct primitives. Ten subjects performed planar point-to-point arm movements paced by a metronome: Starting at 2s the metronome intervals decreased by 36ms per cycle to 200ms, stayed at 200ms for several cycles, then increased by similar increments. Instructions emphasized to insert explicit stops between each movement with a duration that equaled the movement time. The experiment was performed with eyes open and closed, and with short and long metronome sounds, the latter explicitly specifying the dwell duration. Results showed that subjects matched instructed movement times but did not preserve the dwell times. Rather, they progressively reduced dwell time to zero, transitioning to continuous rhythmic movements before movement times reached their minimum. The acceleration profiles showed an abrupt change between discrete and rhythmic profiles. The loss of dwell time occurred earlier with long auditory specification, when subjects also showed evidence of predictive control. While evidence for hysteresis was weak, taken together, the results clearly indicated a transition between discrete and rhythmic movements, supporting the proposal that representation is based on primitives rather than on veridical internal models.

  1. Primary intraspinal extradural primitive neuroectodermal tumor: A rare case

    Science.gov (United States)

    Rege, Shrikant V.; Tadghare, Jitendra; Patil, Harshad; Narayan, Sharadendu

    2016-01-01

    Primitive neuroectodermal tumors (PNETs) are aggressive childhood malignancies and are difficult to treat. Primary intraspinal PNETs are rare. These patients have poor prognosis with short survival time even after surgery and chemoradiation. As there are no standard guidelines exist for the management of these tumors, a multidisciplinary approach has been employed with varying success. According to the review of literature, only few cases of primary intraspinal extradural PNETs have been reported. Herein, author has described a case of intraspinal, extradural PNET. PMID:28217164

  2. Intracranial Ewings Sarcoma/peripheral primitive neuroectodermal tumor

    Directory of Open Access Journals (Sweden)

    R Amita

    2014-01-01

    Full Text Available Central nervous system primitive neuroectodermal tumours (CNS PNET are aggressive embryonal tumours composed of undifferentiated or poorly differentiated neuroepithelial cells seen in the pediatric age group. This is rare and only a handful of cases of ES/pPNET in CNS are reported. We report such a case in a 3 year old child. Reporting of more such cases is needed to better define these rare tumours of the dura.

  3. Thoracic Primitive Neuroectodermal Tumor: An Unusual Case and Literature Review

    Directory of Open Access Journals (Sweden)

    Kubra Erol Kalkan

    2013-01-01

    Full Text Available We describe herein a rare case of a primary primitive neuroectodermal tumor (PNET in the mediastinum of a 75-year-old man. Grossly, the tumor was located in the left upper anterior mediastinum. Transcutaneous fine-needle biopsy (TCNB revealed small round-cell proliferation. The expression immunohistochemical analysis was confirmed the diagnosis of PNET. He was successfully treated with chemotherapy and is alive with no sign of recurrence for 17 months after the diagnosis.

  4. Polycomb enables primitive endoderm lineage priming in embryonic stem cells

    DEFF Research Database (Denmark)

    Illingworth, Robert S; Hölzenspies, Jurriaan J; Roske, Fabian V

    2016-01-01

    Mouse embryonic stem cells (ESCs), like the blastocyst from which they are derived, contain precursors of the epiblast (Epi) and primitive endoderm (PrEn) lineages. While transient in vivo, these precursor populations readily interconvert in vitro. We show that altered transcription is the driver...... polycomb with dynamic changes in transcription and stalled lineage commitment, allowing cells to explore alternative choices prior to a definitive decision....

  5. Primitive neuroectodermal tumor of the liver: a case report.

    Science.gov (United States)

    Mani, Siddhartha; Dutta, Deep; De, Binay K

    2010-03-01

    Ewing sarcoma/primitive neuroectodermal tumor is a rare tumor of soft tissues of thoraco-pulmonary regions, pelvis and lower extremities. Involvement of visceral organs by primitive neuroectodermal tumor is even rarer, with the kidney being the most commonly involved organ. Involvement of the liver has been reported in the form of metastasis from other primary sources presenting as liver abscess. We report a 20-year-old lady presenting with massive hepatomegaly, with computed tomography scan evidence of diffuse hepatomegaly and a normal porta and intrahepatic biliary radicles. She subsequently underwent ultrasonography-guided true-cut needle biopsy of the liver. Histopathology of the liver revealed nests of small round blue tumor cells in the background of hepatocytes infiltrating the liver, which expressed Mic-2 and Fli-1, and were negative for cytokeratin, desmin, hepatocyte-specific antigen (OCHIE5), synaptophysin, chromogranin A and CD-20. Immunohistochemistry revealed CD-99-positive. Extensive search regarding any possible different site of involvement by the tumor was negative. The patient responded to a combination therapy of vincristine, adriamycin and cyclophosphamide alternating with ifosfamide and etoposide 3 weekly over 43 weeks and has been doing well even after 1 year of diagnosis. The clinical presentation, the macroscopic aspect, together with the histological pattern, the cytological characteristic and the cellular immunophenotype lead to the diagnosis of primary primitive neuroectodermal tumor of the liver which responded well to combination chemotherapy.

  6. Intraspinal primitive neuroectodermal tumor: Imaging findings in six cases

    Energy Technology Data Exchange (ETDEWEB)

    Duan Xiaohui [Department of Radiology, The Second Affiliated Hospital, Sun Yat-Sen University, No. 107 Yanjiang Road West, Guangzhou 510120, Guangdong (China); Department of Radiology, Traditional Chinese Medical Hospital of Guangdong Province, No. 111 Dade Road, Guangzhou 510120, Guangdong (China); Ban Xiaohua [Department of Radiology, The Second Affiliated Hospital, Sun Yat-Sen University, No. 107 Yanjiang Road West, Guangzhou 510120, Guangdong (China); Liu Bo [Department of Radiology, Traditional Chinese Medical Hospital of Guangdong Province, No. 111 Dade Road, Guangzhou 510120, Guangdong (China); Zhong Xiaomei; Guo Ruomi; Zhang Fang; Liang Biling [Department of Radiology, The Second Affiliated Hospital, Sun Yat-Sen University, No. 107 Yanjiang Road West, Guangzhou 510120, Guangdong (China); Shen Jun, E-mail: junshenjun@hotmail.com [Department of Radiology, The Second Affiliated Hospital, Sun Yat-Sen University, No. 107 Yanjiang Road West, Guangzhou 510120, Guangdong (China)

    2011-11-15

    Purpose: To retrospectively review CT and MRI findings in a series of six intraspinal primitive neuroectoderal tumors and to find out their radiological features. Methods: CT and MRI of six patients with surgically and pathologically proved intraspinal primitive neuroectoderal tumor were retrospectively reviewed. The tumor location, morphological features, signal intensity, calcification, contrast enhancement characteristics, involvement of paraspinal soft tissues and adjacent bony structures were assessed. Results: Of six patients, four had extradural lesions and two had intradural, extramedullary lesions. Most lesions were well defined and manifested heterogeneous iso- or hypo-intense signal on T1-weighted imaging and hyper-intense signal on T2-weighted imaging and moderate attenuation on CT, and were heterogeneously enhanced after contrast enhancement. The lesion extending through the intervertebral foramen with a large paraspinal soft tissue mass formed was found in four patients and vertebral bone involvement was seen in four patients. Conclusions: Although imaging findings are not specific of intraspinal primitive neuroectoderal tumor, this diagnosis could be suggested when MR imaging depicts an intradural, extramedullary or extradural large well-circumscribed mass which extends out from intervertebral foramen and invades paraspinal soft tissues or vertebral bones in a young patient.

  7. Vesicle aggregates as a model for primitive cellular assemblies.

    Science.gov (United States)

    de Souza, Tereza Pereira; Bossa, Guilherme Volpe; Stano, Pasquale; Steiniger, Frank; May, Sylvio; Luisi, Pier Luigi; Fahr, Alfred

    2017-08-02

    Primitive cell models help to understand the role that compartmentalization plays in origin of life scenarios. Here we present a combined experimental and modeling approach towards the construction of simple model systems for primitive cellular assemblies. Charged lipid vesicles aggregate in the presence of oppositely charged biopolymers, such as nucleic acids or polypeptides. Based on zeta potential measurements, dynamic light scattering and cryo-transmission electron-microscopy, we have characterized the behavior of empty and ferritin-filled large unilamellar POPC vesicles, doped with different amounts of cationic (DDAB, CTAB) and anionic (sodium oleate) surfactants, and their aggregation upon the addition of anionic (tRNA, poly-l-glutamic acid) and cationic (poly-l-arginine) biopolymers, respectively. The experimental results are rationalized by a phenomenological modeling approach that predicts the average size of the vesicle aggregates as function of the amount of added biopolymers. In addition, we discuss the mechanism of vesicle aggregation induced by oppositely charged biopolymers. Our study complements previous reports about the formation of giant vesicle clusters and thus provides a general vista on primitive cell systems, based on the association of vesicles into compartmentalized aggregates.

  8. Synthesis of barbituric acid containing nucleotides and their implications for the origin of primitive informational polymers.

    Science.gov (United States)

    Mungi, Chaitanya V; Singh, Sachin Kumar; Chugh, Jeetender; Rajamani, Sudha

    2016-07-27

    Given that all processes in modern biology are encoded and orchestrated by polymers, the origin of informational molecules had to be a crucial and significant step in the origin of life on Earth. An important molecule in this context is RNA that is thought to have allowed the transition from chemistry to biology. However, the RNA molecule is comprised of intramolecular bonds which are prone to hydrolysis, especially so under the harsh conditions of the early Earth. Furthermore, the formation of nucleotides with extant bases and their subsequent polymerization have both been problematic, to say the least. Alternate heterocycles, in contrast, have resulted in nucleosides in higher yields, suggesting a viable and prebiotically relevant solution to the longstanding "nucleoside problem". In the present study, we have synthesized a nucleotide using ribose 5'-monophosphate (rMP) and barbituric acid (BA), as the base analog, using dry-heating conditions that are thought to be prevalent in several regimes of the early Earth. Polymerization of the resultant monomers, i.e. BA-nucleotides, was also observed when dehydration-rehydration cycles were carried out at low pH and high temperature. The resulting RNA-like oligomers have intact bases unlike in reactions that were carried out with canonical nucleotides, which resulted in abasic sites under acidic conditions due to cleavage of the N-glycosidic linkages. Furthermore, the incorporation of BA directly into preformed sugar-phosphate backbones was also observed when rMP oligomers were subjected to heating with BA. The results from our aforementioned experiments provide preliminary evidence that BA could have been a putative precursor of modern nucleobases, which could have been incorporated into primitive informational polymers that predated the molecules of an RNA world. Moreover, they also highlight that the prebiotic soup, which would have been replete with alternate heterocycles, could have allowed the sampling of other

  9. Drawbacks of the ancient RNA-based life-like system under primitive earth conditions.

    Science.gov (United States)

    Kawamura, Kunio

    2012-07-01

    Following the discovery of ribozymes, the "RNA world" hypothesis has become the most accepted hypothesis concerning the origin of life and genetic information. However, this hypothesis has several drawbacks. Verification of the hypothesis from different viewpoints led us to proposals from the viewpoint of the hydrothermal origin of life, solubility of RNA and related biopolymers, and the possibility of creating an evolutionary system comparable to the in vitro selection technique for functional RNA molecules based on molecular biology. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  10. The Utility of Cognitive Plausibility in Language Acquisition Modeling: Evidence from Word Segmentation

    Science.gov (United States)

    Phillips, Lawrence; Pearl, Lisa

    2015-01-01

    The informativity of a computational model of language acquisition is directly related to how closely it approximates the actual acquisition task, sometimes referred to as the model's "cognitive plausibility." We suggest that though every computational model necessarily idealizes the modeled task, an informative language acquisition…

  11. The Utility of Cognitive Plausibility in Language Acquisition Modeling: Evidence from Word Segmentation

    Science.gov (United States)

    Phillips, Lawrence; Pearl, Lisa

    2015-01-01

    The informativity of a computational model of language acquisition is directly related to how closely it approximates the actual acquisition task, sometimes referred to as the model's "cognitive plausibility." We suggest that though every computational model necessarily idealizes the modeled task, an informative language acquisition…

  12. Plausible Explanation of Quantization of Intrinsic Redshift from Hall Effect and Weyl Quantization

    Directory of Open Access Journals (Sweden)

    Smarandache F.

    2006-10-01

    Full Text Available Using phion condensate model as described by Moffat [1], we consider a plausible explanation of (Tifft intrinsic redshift quantization as described by Bell [6] as result of Hall effect in rotating frame. We also discuss another alternative to explain redshift quantization from the viewpoint of Weyl quantization, which could yield Bohr- Sommerfeld quantization.

  13. “合情推理”辨析%Analysis of Plausible Reasoning

    Institute of Scientific and Technical Information of China (English)

    连四清; 方运加

    2012-01-01

    波利亚的“合情推理”模式引进我国数学课程标准后,就成了我国数学教育研究的关键词。然而,“合情推理”的科学性尚需考证:(1)它的中文意义不明确;(2)它不满足推理模式的客观性要求,存在明显的缺陷;(3)过分强调“合情推理模式”则是过分强调归纳推理和演绎推理的区别,容易割裂它们之间的关系。%After the model of "plausible inference" being introduced into the mathematics curriculum standards, it became a key word of the research on mathematics education in China. However, there are doubts on whether it is scientific. (1) Chinese meaning of plausible inference is ambiguous. (2) The plausible inference can not meet the objective requirement of the reasoning, which has obvious defects. (3) Overemphasizing the model of plausible inference would overemphasize the difference between deductive inference and inductive inference, and would dispart them.

  14. From bone to plausible bipedal locomotion. Part II: Complete motion synthesis for bipedal primates.

    Science.gov (United States)

    Nicolas, Guillaume; Multon, Franck; Berillon, Gilles

    2009-05-29

    This paper addresses the problem of synthesizing plausible bipedal locomotion according to 3D anatomical reconstruction and general hypotheses on human motion control strategies. In a previous paper [Nicolas, G., Multon, F., Berillon, G., Marchal, F., 2007. From bone to plausible bipedal locomotion using inverse kinematics. Journal of Biomechanics 40 (5) 1048-1057], we have validated a method based on using inverse kinematics to obtain plausible lower-limb motions knowing the trajectory of the ankle. In this paper, we propose a more general approach that also involves computing a plausible trajectory of the ankles for a given skeleton. The inputs are the anatomical descriptions of the bipedal species, imposed footprints and a rest posture. This process is based on optimizing a reference ankle trajectory until a set of criteria is minimized. This optimization loop is based on the assumption that a plausible motion is supposed to have little internal mechanical work and should be as less jerky as possible. For each tested ankle trajectory, inverse kinematics is used to compute a lower-body motion that enables us to compute the resulting mechanical work and jerk. This method was tested on a set of modern humans (male and female, with various anthropometric properties). We show that the results obtained with this method are close to experimental data for most of the subjects. We also demonstrate that the method is not sensitive to the choice of the reference ankle trajectory; any ankle trajectory leads to very similar result. We finally apply the method to a skeleton of Pan paniscus (Bonobo), and compare the resulting motion to those described by zoologists.

  15. The origin and early evolution of life on earth

    Science.gov (United States)

    Oro, J.; Miller, Stanley L.; Lazcano, Antonio

    1990-01-01

    Results of the studies that have provided insights into the cosmic and primitive earth environments are reviewed with emphasis on those environments in which life is thought to have originated. The evidence bearing on the antiquity of life on the earth and the prebiotic significance of organic compounds found in interstellar clouds and in primitive solar-system bodies such as comets, dark asteroids, and carbonaceous chondrites are assessed. The environmental models of the Hadean and early Archean earth are discussed, as well as the prebiotic formation of organic monomers and polymers essential to life. The processes that may have led to the appearance in the Archean of the first cells are considered, and possible effects of these processes on the early steps of biological evolution are analyzed. The significance of these results to the study of the distribution of life in the universe is evaluated.

  16. Earth\\'s Mass Variability

    CERN Document Server

    Mawad, Ramy

    2014-01-01

    The perturbation of the Earth caused by variability of mass of Earth as additional reason with gravity of celestial bodies and shape of the Earth. The Earth eating and collecting matters from space and loss or eject matters to space through its flying in the space around the Sun. The source of the rising in the global sea level is not closed in global warming and icebergs, but the outer space is the additional important source for this rising. The Earth eats waters from space in unknown mechanism. The mass of the Earth become greater in November i.e. before transit apoapsis two months, and become latter in February i.e. after transit apoapsis to two months.

  17. Formation of Complex Amino Acid Precursors in Simulated Primitive Atmosphere and Their Alteration under Simulated Submarine Hydrothermal Conditions

    Science.gov (United States)

    Kobayashi, Kensei; Kurihara, Hironari; Hirako, Tomoaki; Obayashi, Yumiko; Kaneko, Takeo; Takano, Yoshinori; Yoshimura, Yoshitaka

    Since late 1970's a great number of submarine hydrothermal systems (SHSs) has been dis-covered, and they are considered possible sites of chemical evolution and generation of life on the Earth since their discovery in late 1970s. A number of experiments simulating the con-ditions of SHSs were conducted, and abiotic production and polymerization of amino acids were reported. Free amino acids were frequently used as starting materials to examine possible organic reactions in the simulation experiments. In our early studies, not free amino acids but complex amino acids precursors with large molecular weights were formed abiotically from simulated primitive Earth atmosphere (a mixture of CO, N2 and H2 O) (Takano et al., 2004). Such complex organics (hereafter referred as to CNWs) should have been delivered to SHSs in Primitive Ocean, where they were subjected to further alteration. We examined possible alteration of the complex organics in high-temperature high-pressure environments by the su-percritical water flow reactor (SCWFR) (Islam et al.. 2003) and an autoclave. CNWs were quite hydrophilic compounds whose molecular weights were ca. 3000. After heating 573 K for 2 min in the SCWFR, aggregates of organics were formed, which were separated from aque-ous solution with a Nucleopore filter (pore size: 200 nm). We propose the following scenario of chemical evolution: (1) Complex organics including amino acid precursors were formed in primitive atmosphere and/or extraterrestrial environments, (ii) they were delivered to primor-dial SHSs, (iii) hydrothermal alteration occurred in SHSs to give organic aggregates, (iv) quite primitive molecular systems with subtle biological functions were generated in the competition among such aggregates. References: Islam, Md. N., Kaneko, T., and Kobayashi, K (2003). Reactions of Amino Acids with a Newly ConstructedSupercritical Water Flow Reactor Simulating Submarine Hydrothermal Systems. Bull. Chem. Soc. Jpn., 76, 1171. Takano, Y

  18. Epithelial neoplasia in Drosophila entails switch to primitive cell states.

    Science.gov (United States)

    Khan, Sumbul J; Bajpai, Anjali; Alam, Mohammad Atif; Gupta, Ram P; Harsh, Sneh; Pandey, Ravi K; Goel-Bhattacharya, Surbhi; Nigam, Aditi; Mishra, Arati; Sinha, Pradip

    2013-06-11

    Only select cell types in an organ display neoplasia when targeted oncogenically. How developmental lineage hierarchies of these cells prefigure their neoplastic propensities is not yet well-understood. Here we show that neoplastic Drosophila epithelial cells reverse their developmental commitments and switch to primitive cell states. In a context of alleviated tissue surveillance, for example, loss of Lethal giant larvae (Lgl) tumor suppressor in the wing primordium induced epithelial neoplasia in its Homothorax (Hth)-expressing proximal domain. Transcriptional profile of proximally transformed mosaic wing epithelium and functional tests revealed tumor cooperation by multiple signaling pathways. In contrast, lgl(-) clones in the Vestigial (Vg)-expressing distal wing epithelium were eliminated by cell death. Distal lgl(-) clones, however, could transform when both tissue surveillance and cell death were compromised genetically and, alternatively, when the transcription cofactor of Hippo signaling pathway, Yorkie (Yki), was activated, or when Ras/EGFR signaling was up-regulated. Furthermore, transforming distal lgl(-) clones displayed loss of Vg, suggesting reversal of their terminal cell fate commitment. In contrast, reinforcing a distal (wing) cell fate commitment in lgl(-) clones by gaining Vg arrested their neoplasia and induced cell death. We also show that neoplasia in both distal and proximal lgl(-) clones could progress in the absence of Hth, revealing Hth-independent wing epithelial neoplasia. Likewise, neoplasia in the eye primordium resulted in loss of Elav, a retinal cell marker; these, however, switched to an Hth-dependent primitive cell state. These results suggest a general characteristic of "cells-of-origin" in epithelial cancers, namely their propensity for switch to primitive cell states.

  19. Vertical spectral representation in primitive equation models of the atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Mizzi, A.; Tribbia, J. [National Center for Atmospheric Research, Boulder, CO (United States); Curry, J. [Univ. of Colorado, Boulder, CO (United States)

    1995-08-01

    Attempts to represent the vertical structure in primitive equation models of the atmosphere with the spectral method have been unsuccessful to date. Linear stability analysis showed that small time steps were required for computational stability near the upper boundary with a vertical spectral representation and found it necessary to use an artificial constraint to force temperature to zero when pressure was zero to control the upper-level horizontal velocities. This ad hoc correction is undesirable, and an analysis that shows such a correction is unnecessary is presented. By formulating the model in terms of velocity and geopotential and then using the hydrostatic equation to calculate temperature from geopotential, temperature is necessarily zero when pressure is zero. The authors applied this technique to the dry-adiabatic primitive equations on the equatorial {beta} and tropical f planes. Vertical and horizontal normal modes were used as the spectral basis functions. The vertical modes are based on vertical normal modes, and the horizontal modes are normal modes for the primitive equations on a {beta} or f plane. The results show that the upper-level velocities do not necessarily increase, total energy is conserved, and kinetic energy is bounded. The authors found an upper-level temporal oscillation in the horizontal domain integral of the horizontal velocity components that is related to mass and velocity field imbalances in the initial conditions or introduced during the integration. Through nonlinear normal-mode initialization, the authors effectively removed the initial condition imbalance and reduced the amplitude of this oscillation. It is hypothesized that the vertical spectral representation makes the model more sensitive to initial condition imbalances, or it introduces imbalance during the integration through vertical spectral truncation. 20 refs., 12 figs.

  20. Fully Implicit Numerical Methods for the Baroclinic Primitive Equations

    Science.gov (United States)

    Cohn, S. E.; Isaacson, E.

    1984-01-01

    A fully implicit code was developed to solve the three-dimensional primitive equations of atmospheric flow. The scheme is second order accurate in time and fourth order accurate in the horizontal and vertical directions. Furthermore, as a result of being fully implicit, the time step is not restricted by the mesh spacing near the poles, nor by the speed of inertia-gravity waves. Rather, the time step, deltat is determined simply by the requirement that it be small enough to adequately resolve the atmospheric flow of interest. The accuracy and efficiency of current models for fine grids should be significantly improved.

  1. Characterizing Digital Light Processing (DLP) 3D Printed Primitives

    DEFF Research Database (Denmark)

    Tyge, Emil; Pallisgaard, Jens J.; Lillethorup, Morten

    2015-01-01

    The resolution and repeatability of 3D printing processes depends on a number of factors including the software, hardware, and material used. When printing parts with features that are near or below the nominal printing resolution, it is important to understand how the printer works. For example......, what is the smallest unit shape that can be produced? And what is the reproducibility of that process? This paper presents a method for automatically detecting and characterizing the height, width, and length of micro scale geometric primitives produced via a digital light processing (DLP) 3D printing...

  2. Hardware/Software Co-design using Primitive Interface

    Directory of Open Access Journals (Sweden)

    Navin Chourasia

    2011-08-01

    Full Text Available Most engineering designs can be viewed as systems, i.e., as collections of several components whose combined operation provides useful services. Components can be heterogeneous in nature and their interaction may be regulated by some simple or complex means. Interface between Hardware & Software plays a very important role in co-design of the embedded system. Hardware/software co-design means meeting system-level objectives by exploiting the synergism of hardware and software through their concurrent design. This paper shows how hardware & software interfaces can be implemented using primitive interface design

  3. Primitive endoderm differentiation: from specification to epithelium formation.

    Science.gov (United States)

    Hermitte, Stéphanie; Chazaud, Claire

    2014-12-05

    In amniotes, primitive endoderm (PrE) plays important roles not only for nutrient support but also as an inductive tissue required for embryo patterning. PrE is an epithelial monolayer that is visible shortly before embryo implantation and is one of the first three cell lineages produced by the embryo. We review here the molecular mechanisms that have been uncovered during the past 10 years on PrE and epiblast cell lineage specification within the inner cell mass of the blastocyst and on their subsequent steps of differentiation.

  4. Primitive neuroectodermal tumor of the kidney: a case report

    Energy Technology Data Exchange (ETDEWEB)

    Kim, See Hyung; Cho, Jae Ho; Chang, Jay Chun; Park, Bok Hawn [School of Medicine, Yeungnam Univ., Daegu (Korea, Republic of)

    2002-07-01

    Primitive neuroectodermal tumor (PNET) is relatively uncommon, arising outside the central nervous system. Very rarely, it occurs within the urinary system. A 55-year-old woman presented with gross hematuria and right flank pain which had begun two months earlier. A well-marginated, low-density mass containing high-density portions representing hemorrhage was seen in the right kidney at pre-enhanced CT; contrast enhancement was not prominent. As both T1- and T2- weighted MR imaging, a multilocular cystic mass with high signal intensity portions representing hemorrhage was observed. Contrast enhancement was absent. We report the radiologic findings in the case of renal PNET.

  5. Thoracoabdominal peripheral primitive neuroectodermal tumors in childhood: radiological features

    Energy Technology Data Exchange (ETDEWEB)

    Schulman, H.; Laufer, L. [University Medical Center, Beer-Sheva (Israel). Dept. of Radiology; Newman-Heinman, N.; Kurtzbart, E. [Soroka Univ. Medical Center, Beer-Sheva (Israel). Dept. of Pediatrics; Maor, E.; Zirkin, H. [Soroka Univ. Medical Center, Beer-Sheva (Israel). Dept. of Pathology

    2000-10-01

    Peripheral primitive neuroectodermal tumors (PNET) are extremely uncommon, malignant neoplasms affecting mostly children and young adults. We retrospectively reviewed the clinical data and radiological studies of four such cases. All cases were pathologically proven. Plain films, US, and CT scans were used. The youngest child had a huge pelvic tumor and two adolescents each had a chest wall (Askin) tumor. The fourth patient had a most unusual location of the PNET in the anterior mediastinum. The CT findings are emphasized. We emphasize that the markedly abnormal CT findings are not specific for PNET. (orig.)

  6. An Incidentaloma: Primitive Neuroectodermal Tumor of the Thymus

    Directory of Open Access Journals (Sweden)

    Suzanne M. Smith

    2011-01-01

    Full Text Available After presenting for a routine screening exam, and 57-year-old man was diagnosed with an incidentaloma—a primitive neuroectodermal tumor (PNET of the thymus. A member of the Ewing sarcoma family of tumors, a PNET is typically regarded as a malignancy of childhood and adolescence, usually occurring in the central nervous system. In the case at hand, our patient had an extremely unusual presentation, given his age and tumor location. Initial presentation is the only predictor for long-term survival. Current treatment recommendations advocate complete surgical resection whenever possible, radiation therapy, and adjuvant versus neoadjuvant chemotherapy.

  7. Primary intraspinal extradural primitive neuroectodermal tumor: A rare case

    Directory of Open Access Journals (Sweden)

    Shrikant V Rege

    2016-01-01

    Full Text Available Primitive neuroectodermal tumors (PNETs are aggressive childhood malignancies and are difficult to treat. Primary intraspinal PNETs are rare. These patients have poor prognosis with short survival time even after surgery and chemoradiation. As there are no standard guidelines exist for the management of these tumors, a multidisciplinary approach has been employed with varying success. According to the review of literature, only few cases of primary intraspinal extradural PNETs have been reported. Herein, author has described a case of intraspinal, extradural PNET.

  8. Renal primitive neuroectodermal tumor: does age at diagnosis impact outcomes?

    Directory of Open Access Journals (Sweden)

    Mahkameh Zare

    2012-01-01

    Full Text Available Primitive n euroectodermal tumor (PNET of the kidney is a rare and highly malignant neoplasm. The median age for renal PNET is 27 years but it can be seen also in a wide age range between 3 and 78 years. We performed a Medline search for the term renal PNET and identified 79 cases up till December of 2010. We report here a new case of renal PNET and a literature review for published data for evaluation of clinicopathological prognostic factors, with an emphasis on prognosis in two groups of adults and children-adolescents: 18 years of age or under and over 18 years.

  9. Supratentorial primitive neuroectodermal tumor presenting with intracranial hemorrhage in adult

    Directory of Open Access Journals (Sweden)

    Bashar Abuzayed

    2014-01-01

    Full Text Available A 24-year-old female patient presented with complaints of nausea, vomiting and of loss of consciousness lasted for 15 minutes with left sided weakness. Neuroradiological evaluation revealed a hemorrhagic mass lesion in the right frontal lobe. The patient was operated and intraoperative findings showed a cortical-subcortical hematoma including hemorrhagic and disrupted tissue with a pathologic purple tissue on the periphery of the hematoma. Postoperative course was uneventful and postoperative histopathological examination revealed primitive neuroectodermal tumor. The patient was then referred to medical and radiation oncology clinics for further evaluation and treatment.

  10. Quasi-hydrostatic Primitive Equations for Ocean Global Circulation Models

    Institute of Scientific and Technical Information of China (English)

    Carine LUCAS; Madalina PETCU; Antoine ROUSSEAU

    2010-01-01

    Global existence of weak and strong solutions to the quasi-hydrostatic primitive equations is studied in this paper.This model,that derives from the full non-hydrostatic model for geophysical fluid dynamics in the zero-limit of the aspect ratio,is more realistic than the classical hydrostatic model,since the traditional approximation that consists in neglecting a part of the Coriolis force is relaxed.After justifying the derivation of the model,the authors provide a rigorous proof of global existence of weak solutions,and well-posedness for strong solutions in dimension three.

  11. Dust formation in a galaxy with primitive abundances.

    Science.gov (United States)

    Sloan, G C; Matsuura, M; Zijlstra, A A; Lagadec, E; Groenewegen, M A T; Wood, P R; Szyszka, C; Bernard-Salas, J; van Loon, J Th

    2009-01-16

    Interstellar dust plays a crucial role in the evolution of galaxies. It governs the chemistry and physics of the interstellar medium. In the local universe, dust forms primarily in the ejecta from stars, but its composition and origin in galaxies at very early times remain controversial. We report observational evidence of dust forming around a carbon star in a nearby galaxy with a low abundance of heavy elements, 25 times lower than the solar abundance. The production of dust by a carbon star in a galaxy with such primitive abundances raises the possibility that carbon stars contributed carbonaceous dust in the early universe.

  12. Biologically plausible learning in recurrent neural networks reproduces neural dynamics observed during cognitive tasks.

    Science.gov (United States)

    Miconi, Thomas

    2017-02-23

    Neural activity during cognitive tasks exhibits complex dynamics that flexibly encode task-relevant variables. Chaotic recurrent networks, which spontaneously generate rich dynamics, have been proposed as a model of cortical computation during cognitive tasks. However, existing methods for training these networks are either biologically implausible, and/or require a continuous, real-time error signal to guide learning. Here we show that a biologically plausible learning rule can train such recurrent networks, guided solely by delayed, phasic rewards at the end of each trial. Networks endowed with this learning rule can successfully learn nontrivial tasks requiring flexible (context-dependent) associations, memory maintenance, nonlinear mixed selectivities, and coordination among multiple outputs. The resulting networks replicate complex dynamics previously observed in animal cortex, such as dynamic encoding of task features and selective integration of sensory inputs. We conclude that recurrent neural networks offer a plausible model of cortical dynamics during both learning and performance of flexible behavior.

  13. Identifying plausible genetic models based on association and linkage results: application to type 2 diabetes.

    Science.gov (United States)

    Guan, Weihua; Boehnke, Michael; Pluzhnikov, Anna; Cox, Nancy J; Scott, Laura J

    2012-12-01

    When planning resequencing studies for complex diseases, previous association and linkage studies can constrain the range of plausible genetic models for a given locus. Here, we explore the combinations of causal risk allele frequency (RAFC ) and genotype relative risk (GRRC ) consistent with no or limited evidence for affected sibling pair (ASP) linkage and strong evidence for case-control association. We find that significant evidence for case-control association combined with no or moderate evidence for ASP linkage can define a lower bound for the plausible RAFC . Using data from large type 2 diabetes (T2D) linkage and genome-wide association study meta-analyses, we find that under reasonable model assumptions, 23 of 36 autosomal T2D risk loci are unlikely to be due to causal variants with combined RAFC < 0.005, and four of the 23 are unlikely to be due to causal variants with combined RAFC < 0.05.

  14. Acquiring Plausible Predications from MEDLINE by Clustering MeSH Annotations.

    Science.gov (United States)

    Miñarro-Giménez, Jose Antonio; Kreuzthaler, Markus; Bernhardt-Melischnig, Johannes; Martínez-Costa, Catalina; Schulz, Stefan

    2015-01-01

    The massive accumulation of biomedical knowledge is reflected by the growth of the literature database MEDLINE with over 23 million bibliographic records. All records are manually indexed by MeSH descriptors, many of them refined by MeSH subheadings. We use subheading information to cluster types of MeSH descriptor co-occurrences in MEDLINE by processing co-occurrence information provided by the UMLS. The goal is to infer plausible predicates to each resulting cluster. In an initial experiment this was done by grouping disease-pharmacologic substance co-occurrences into six clusters. Then, a domain expert manually performed the assignment of meaningful predicates to the clusters. The mean accuracy of the best ten generated biomedical facts of each cluster was 85%. This result supports the evidence of the potential of MeSH subheadings for extracting plausible medical predications from MEDLINE.

  15. Spelling in oral deaf and hearing dyslexic children: A comparison of phonologically plausible errors.

    Science.gov (United States)

    Roy, P; Shergold, Z; Kyle, F E; Herman, R

    2014-11-01

    A written single word spelling to dictation test and a single word reading test were given to 68 severe-profoundly oral deaf 10-11-year-old children and 20 hearing children with a diagnosis of dyslexia. The literacy scores of the deaf children and the hearing children with dyslexia were lower than expected for children of their age and did not differ from each other. Three quarters of the spelling errors of hearing children with dyslexia compared with just over half the errors of the oral deaf group were phonologically plausible. Expressive vocabulary and speech intelligibility predicted the percentage of phonologically plausible errors in the deaf group only. Implications of findings for the phonological decoding self-teaching model and for supporting literacy development are discussed.

  16. Of paradox and plausibility: the dynamic of change in medical law.

    Science.gov (United States)

    Harrington, John

    2014-01-01

    This article develops a model of change in medical law. Drawing on systems theory, it argues that medical law participates in a dynamic of 'deparadoxification' and 'reparadoxification' whereby the underlying contingency of the law is variously concealed through plausible argumentation, or revealed by critical challenge. Medical law is, thus, thoroughly rhetorical. An examination of the development of the law on abortion and on the sterilization of incompetent adults shows that plausibility is achieved through the deployment of substantive common sense and formal stylistic devices. It is undermined where these elements are shown to be arbitrary and constructed. In conclusion, it is argued that the politics of medical law are constituted by this antagonistic process of establishing and challenging provisionally stable normative regimes.

  17. On the plausible association between environmental conditions and human eye damage.

    Science.gov (United States)

    Feretis, Elias; Theodorakopoulos, Panagiotis; Varotsos, Costas; Efstathiou, Maria; Tzanis, Christos; Xirou, Tzina; Alexandridou, Nancy; Aggelou, Michael

    2002-01-01

    The increase in solar ultraviolet radiation can have various direct and indirect effects on human health, like the incidence of ocular damage. Data of eye damage in residents of three suburban regions in Greece and in two groups of monks/nuns and fishermen are examined here. The statistics performed on these data provides new information about the plausible association between increased levels of solar ultraviolet radiation, air-pollution at ground level, and the development of ocular defects.

  18. Families of Plausible Solutions to the Puzzle of Boyajian’s Star

    Science.gov (United States)

    Wright, Jason T.; Sigurd̵sson, Steinn

    2016-09-01

    Good explanations for the unusual light curve of Boyajian's Star have been hard to find. Recent results by Montet & Simon lend strength and plausibility to the conclusion of Schaefer that in addition to short-term dimmings, the star also experiences large, secular decreases in brightness on decadal timescales. This, combined with a lack of long-wavelength excess in the star's spectral energy distribution, strongly constrains scenarios involving circumstellar material, including hypotheses invoking a spherical cloud of artifacts. We show that the timings of the deepest dimmings appear consistent with being randomly distributed, and that the star's reddening and narrow sodium absorption is consistent with the total, long-term dimming observed. Following Montet & Simon's encouragement to generate alternative hypotheses, we attempt to circumscribe the space of possible explanations with a range of plausibilities, including: a cloud in the outer solar system, structure in the interstellar medium (ISM), natural and artificial material orbiting Boyajian's Star, an intervening object with a large disk, and variations in Boyajian's Star itself. We find the ISM and intervening disk models more plausible than the other natural models.

  19. What happened (and what didn't): Discourse constraints on encoding of plausible alternatives.

    Science.gov (United States)

    Fraundorf, Scott H; Benjamin, Aaron S; Watson, Duane G

    2013-10-01

    Three experiments investigated how font emphasis influences reading and remembering discourse. Although past work suggests that contrastive pitch contours benefit memory by promoting encoding of salient alternatives, it is unclear both whether this effect generalizes to other forms of linguistic prominence and how the set of alternatives is constrained. Participants read discourses in which some true propositions had salient alternatives (e.g., British scientists found the endangered monkey when the discourse also mentioned French scientists) and completed a recognition memory test. In Experiments 1 and 2, font emphasis in the initial presentation increased participants' ability to later reject false statements about salient alternatives but not about unmentioned items (e.g., Portuguese scientists). In Experiment 3, font emphasis helped reject false statements about plausible alternatives, but not about less plausible alternatives that were nevertheless established in the discourse. These results suggest readers encode a narrow set of only those alternatives plausible in the particular discourse. They also indicate that multiple manipulations of linguistic prominence, not just prosody, can lead to consideration of alternatives.

  20. A biologically plausible model of time-scale invariant interval timing.

    Science.gov (United States)

    Almeida, Rita; Ledberg, Anders

    2010-02-01

    The temporal durations between events often exert a strong influence over behavior. The details of this influence have been extensively characterized in behavioral experiments in different animal species. A remarkable feature of the data collected in these experiments is that they are often time-scale invariant. This means that response measurements obtained under intervals of different durations coincide when plotted as functions of relative time. Here we describe a biologically plausible model of an interval timing device and show that it is consistent with time-scale invariant behavior over a substantial range of interval durations. The model consists of a set of bistable units that switch from one state to the other at random times. We first use an abstract formulation of the model to derive exact expressions for some key quantities and to demonstrate time-scale invariance for any range of interval durations. We then show how the model could be implemented in the nervous system through a generic and biologically plausible mechanism. In particular, we show that any system that can display noise-driven transitions from one stable state to another can be used to implement the timing device. Our work demonstrates that a biologically plausible model can qualitatively account for a large body of data and thus provides a link between the biology and behavior of interval timing.

  1. Inorganic chemistry of O2 in a dense primitive atmosphere

    Science.gov (United States)

    Rosenqvist, J; Chassefière, E

    1995-01-01

    A simple steady-state photochemical model is developed in order to determine typical molecular oxygen concentrations for a comprehensive range of primitive abiotic atmospheres. Carbon dioxide is assumed to be the dominant constituent in these atmospheres since CO2 photodissociation may potentially result in the enhancement of the O2 partial pressure. The respective effects of the H2O content, temperature, eddy diffusion coefficient and UV flux on the results are investigated. It is shown that for any pressure at the surface, the partial pressure of molecular oxygen does not exceed 10 mbar. The peculiar case of a runaway greenhouse which has possibly taken place on Venus is qualitatively envisaged. Although O2 is basically absent in the present Venus atmosphere, a transient presence in a primitive stage cannot be ruled out. Possible mechanisms for O2 removal in such an atmosphere are reviewed. At the present stage, we think that the detection of large O2 amounts would be at least a good clue for the presence of life on an extrasolar planet.

  2. Primitive soft-bodied cephalopods from the Cambrian.

    Science.gov (United States)

    Smith, Martin R; Caron, Jean-Bernard

    2010-05-27

    The exquisite preservation of soft-bodied animals in Burgess Shale-type deposits provides important clues into the early evolution of body plans that emerged during the Cambrian explosion. Until now, such deposits have remained silent regarding the early evolution of extant molluscan lineages-in particular the cephalopods. Nautiloids, traditionally considered basal within the cephalopods, are generally depicted as evolving from a creeping Cambrian ancestor whose dorsal shell afforded protection and buoyancy. Although nautiloid-like shells occur from the Late Cambrian onwards, the fossil record provides little constraint on this model, or indeed on the early evolution of cephalopods. Here, we reinterpret the problematic Middle Cambrian animal Nectocaris pteryx as a primitive (that is, stem-group), non-mineralized cephalopod, based on new material from the Burgess Shale. Together with Nectocaris, the problematic Lower Cambrian taxa Petalilium and (probably) Vetustovermis form a distinctive clade, Nectocarididae, characterized by an open axial cavity with paired gills, wide lateral fins, a single pair of long, prehensile tentacles, a pair of non-faceted eyes on short stalks, and a large, flexible anterior funnel. This clade extends the cephalopods' fossil record by over 30 million years, and indicates that primitive cephalopods lacked a mineralized shell, were hyperbenthic, and were presumably carnivorous. The presence of a funnel suggests that jet propulsion evolved in cephalopods before the acquisition of a shell. The explosive diversification of mineralized cephalopods in the Ordovician may have an understated Cambrian 'fuse'.

  3. CT and MR findings of primitive neuroectodermal tumor

    Energy Technology Data Exchange (ETDEWEB)

    Kook, Shin Ho; Kim, In One; Chang, Kee Hyun; Han, Moon Hee; Cho, Byung Kyu [Seoul National University Collge of Medicine, Seoul (Korea, Republic of)

    1991-07-15

    Cerebral primitive neuroectodermal tumor (PNET), consisting of undifferentiated primitive cells, is a neoplasm of children and young adults that occurs predominantly in the supratentorial compartment. In this report, we retrospectively reviewed and analyzed 18 CT and 6 MR findings in 18 patients with pathologically-proven PNET to discover the characteristic findings, if may. The most characteristic feature of the PNETs was a well-defined multilobular oval or round large mass with components of peripheral cystic change or calcification in the cerebral hemisphere, especially in the parietal lobe. Usually there was only minimal surrounding edema. The CT density of the tumor was iso - or slightly high density with homogeneous contrast enhancement in the solid portion and low density in the cystic area. MR findings demonstrated iso - signal intensity on both T1 - weighted (T1WI) and T2-weighted (T2WI) images and dense enhancement in the solid element. The cystic portion revealed low intensity on T1WI and high intensity on T2WI.

  4. Peripheral primitive neuroectodermal tumors:a rare case report

    Institute of Scientific and Technical Information of China (English)

    Kun Yan; Yanyan Ge; Youhong Ding; Shiguang Yan; Xiangyang Li

    2014-01-01

    We-aimed-to-explore-the-diagnosis-and-treatment-of-peripheral-primitive-neuroectodermal-tumors-(pPNETs).-We-retrospectively-analyzed-the-diagnosis-and-treatment-process-of-a-patient-who-was-diagnosed-with-pPNETs-by-pathology.-This-case-was-a-man-with-soft-masses-arising-from-the-left-chest-wal-near-the-armpit-and-left-supraclavicular-of-a-47-year-old-man.-The-patient-mainly-presented-with-the-masses-which-increasing-gradual-y-with-obvious-pain.-Needle-biopsy-showed-that-they-were-both-metastatic-adenocarcinoma.-Ultrasonography-B-revealed-blood-flow-of-these-two-low-density-placeholders-can-be-seen-in-the-signal,-not-oppression-axil-ary-and-vein.-Radical-resection-of-the-masses-were-performed.-Histopathologic-study-and-immunohistochemistry-(IHC)-confirmed-the-masses-to-be-peripheral-primitive-neuroectodermal-tumors.-pPNETs-is-a-rare-malignant-smal-round-cel-tumor.-CT-and-MRI-examination-can-estimate-the-resectability-of-the-tumor;Ultrasound-B-can-make-sure-its-inside-blood-supply-and-the-positional-relationship-between-the-mass-and-the-surrounding-vasculature.-The-diagnosis-of-pPNETs-is-based-primarily-on-histopathologic-study-and-IHC,-especial-y-those-with-the-characteristics-of-the-Homer-Wright-and-neuroendocrine-markers.-Radical-resection-of-the-tumor-is-the-most-ef-ective-therapeutic-method.-The-ef-ect-of-adjuvant-chemo-radiation-is-worth-af-irmation.-Autologous-stem-cel-rescue-besides-adjuvant-chemotherapy-has-been-associated-with-prolonged-survival.

  5. Model selection for the extraction of movement primitives.

    Science.gov (United States)

    Endres, Dominik M; Chiovetto, Enrico; Giese, Martin A

    2013-01-01

    A wide range of blind source separation methods have been used in motor control research for the extraction of movement primitives from EMG and kinematic data. Popular examples are principal component analysis (PCA), independent component analysis (ICA), anechoic demixing, and the time-varying synergy model (d'Avella and Tresch, 2002). However, choosing the parameters of these models, or indeed choosing the type of model, is often done in a heuristic fashion, driven by result expectations as much as by the data. We propose an objective criterion which allows to select the model type, number of primitives and the temporal smoothness prior. Our approach is based on a Laplace approximation to the posterior distribution of the parameters of a given blind source separation model, re-formulated as a Bayesian generative model. We first validate our criterion on ground truth data, showing that it performs at least as good as traditional model selection criteria [Bayesian information criterion, BIC (Schwarz, 1978) and the Akaike Information Criterion (AIC) (Akaike, 1974)]. Then, we analyze human gait data, finding that an anechoic mixture model with a temporal smoothness constraint on the sources can best account for the data.

  6. Model selection for the extraction of movement primitives

    Directory of Open Access Journals (Sweden)

    Dominik M Endres

    2013-12-01

    Full Text Available A wide range of blind source separation methods have been used in motor control research for the extraction of movement primitives from EMG and kinematic data. Popular examples are principal component analysis (PCA,independent component analysis (ICA, anechoic demixing, and the time-varying synergy model. However, choosing the parameters of these models, or indeed choosing the type of model, is often done in a heuristic fashion, driven by result expectations as much as by the data. We propose an objective criterion which allows to select the model type, number of primitives and the temporal smoothness prior. Our approach is based on a Laplace approximation to the posterior distribution of the parameters of a given blind source separation model, re-formulated as a Bayesian generative model.We first validate our criterion on ground truth data, showing that it performs at least as good as traditional model selection criteria (Bayesian information criterion, BIC and the Akaike Information Criterion (AIC. Then, we analyze human gait data, finding that an anechoic mixture model with a temporal smoothness constraint on the sources can best account for the data.

  7. Medulloblastomas and central nervous system primitive neuroectodermal tumors.

    Science.gov (United States)

    McLean, Thomas W

    2003-12-01

    Significant advances in the treatment of medulloblastoma and primitive neuroectodermal tumors have been made in the past three decades. Maximal surgical resection is a mainstay of therapy. However, unlike many other central nervous system neoplasms, medulloblastoma and primitive neuroectodermal tumors are radiation and chemotherapy responsive. Despite this response, the prognosis for patients with these tumors remains variable and is relatively poor in infants and patients with metastatic disease. These tumors most commonly arise in children, thus most clinical trials emphasize the reduction of long-term sequelae, in addition to improving survival. All newly diagnosed patients who are eligible should be offered participation in a clinical trial. If a patient is ineligible or declines consent/assent for a clinical trial, the best current treatment approach is surgical resection, followed by radiation therapy (except for children younger than 3 years) with weekly vincristine. For high-risk patients, 36 Gy of craniospinal irradiation should be delivered plus a boost of 19.8 Gy to the posterior fossa/primary tumor bed and sites of bulk metastatic disease. For average-risk patients, the craniospinal irradiation dose may be lowered to 23.4 Gy plus 32.4 Gy to the posterior fossa/tumor bed. After radiation therapy, intensive multimodal chemotherapy should be used for all patients.

  8. An online gait generator for quadruped walking using motor primitives

    Directory of Open Access Journals (Sweden)

    Chunlin Zhou

    2016-11-01

    Full Text Available This article presents implementation of an online gait generator on a quadruped robot. Firstly, the design of a quadruped robot is presented. The robot contains four leg modules each of which is constructed by a 2 degrees of freedom (2-DOF five-bar parallel linkage mechanism. Together with other two rotational DOF, the leg module is able to perform 4-DOF movement. The parallel mechanism of the robot allows all the servos attached on the body frame, so that the leg mass is decreased and motor load can be balanced. Secondly, an online gait generator based on dynamic movement primitives for the walking control is presented. Dynamic movement primitives provide an approach to generate periodic trajectories and they can be modulated in real time, which makes the online adjustment of walking gaits possible. This gait controller is tested by the quadruped robot in regulating walking speed, switching between forward\\backward movements and steering. The controller is easy to apply, expand and is quite effective on phase coordination and online trajectory modulation. Results of simulated experiments are presented.

  9. ON THE 3D VISCOUS PRIMITIVE EQUATIONS OF THE LARGE-SCALE ATMOSPHERE

    Institute of Scientific and Technical Information of China (English)

    Guo Boling; Huang Daiwen

    2009-01-01

    This paper is devoted to considering the three-dimensional viscous primitive equations of the large-scale atmosphere. First, we prove the global well-posedness for the primitive equations with weaker initial data than that in [11]. Second, we obtain the existence of smooth solutions to the equations. Moreover, we obtain the compact global attractor in V for the dynamical system generated by the primitive equations of large-scale atmosphere, which improves the result of [11].

  10. Earth materials and earth dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Bennett, K; Shankland, T. [and others

    2000-11-01

    In the project ''Earth Materials and Earth Dynamics'' we linked fundamental and exploratory, experimental, theoretical, and computational research programs to shed light on the current and past states of the dynamic Earth. Our objective was to combine different geological, geochemical, geophysical, and materials science analyses with numerical techniques to illuminate active processes in the Earth. These processes include fluid-rock interactions that form and modify the lithosphere, non-linear wave attenuations in rocks that drive plate tectonics and perturb the earth's surface, dynamic recrystallization of olivine that deforms the upper mantle, development of texture in high-pressure olivine polymorphs that create anisotropic velocity regions in the convecting upper mantle and transition zone, and the intense chemical reactions between the mantle and core. We measured physical properties such as texture and nonlinear elasticity, equation of states at simultaneous pressures and temperatures, magnetic spins and bonding, chemical permeability, and thermal-chemical feedback to better characterize earth materials. We artificially generated seismic waves, numerically modeled fluid flow and transport in rock systems and modified polycrystal plasticity theory to interpret measured physical properties and integrate them into our understanding of the Earth. This is the final report of a three-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL).

  11. The survival of early Earth mantle reservoirs: Evidence from flood basalts

    Science.gov (United States)

    Jackson, M. G.

    2011-12-01

    Over geologic time, large quantities of oceanic crust and sediment have been injected into the mantle at subduction zones, thereby generating heterogeneities in the mantle. The mantle has been further modified by melt extraction at mid-ocean ridges, a process that has generated large depleted reservoirs throughout the mantle. Owing to the fact that the Earth's mantle mixes and stirs chaotically on geologic timescales, it has long been thought that any evidence of an early terrestrial primitive mantle reservoir has either been erased by melt extraction, or has been overprinted by mixing with recycled materials. This hypothesis was supported by a lack of evidence for chondritic primitive mantle material in the mantle sources of oceanic hotspots, which are thought to yield material from the Earth's deep mantle. Instead, ocean island basalts (OIB) exhibit median 143Nd/144Nd isotopic ratios near 0.5130, suggesting that plume fed hotspots sample a largely-depleted mantle. However, the discovery of Boyet and Carlson (2005, Science) presented evidence that the Earth's primitive mantle may not be chondritic in composition. Boyet and Carlson (2005) found that modern terrestrial lavas have 142Nd/144Nd ratios ~18 ppm higher than chondrites. This result implies that all modern crustal and mantle reservoirs derive from a reservoir with Sm/Nd ratios ~5% higher than chondritic. Today, the 143Nd/144Nd of the primitive (albeit non-chondritic) reservoir would be ~0.5130. Critically, this value is similar to the median 143Nd/144Nd ratio identified in OIB lavas, suggesting that the OIB mantle may in fact be a largely primitive reservoir. However, most OIB lavas fail to exhibit the elevated 3He/4He ratios associated with primitive mantle reservoirs. Similarly, OIB lavas generally lack primitive Pb-isotopic compositions that plot on the geochron, a requirement for all early-Earth reservoirs. To date, no terrestrial OIB lavas have been found that exhibit the required He, Nd and Pb

  12. Why are so many primitive stars observed in the Galaxy halo?

    CERN Document Server

    Gibson, Carl H; Schild, Rudolph E

    2012-01-01

    Small values of lithium observed in a small, primitive, Galaxy-Halo star SDSS J102915 + 172927 cannot be explained using the standard cold dark matter CDM theory of star formation, but are easily understood using the Gibson/Schild 1996 hydrogravitationaldynamics (HGD) theory. From HGD, primordial H-4He gas fragments into Earth-mass planets in trillion-planet proto-globular-star-cluster (PGC) clumps at the 300 Kyr time of transition from the plasma epoch, soon after the big bang. The first HGD stars formed from pristine, frictionally-merging, gas-planets within the gently stressed clumps of the early universe, burning most available lithium in brown-dwarfs and hot-stars before creating metals that permit cooler burning. The Caffau halo star is a present day example. CDM first stars (Population III) were massive and promptly exploded, reionizing the gas of the universe and seeding it with metals, thus making the observed star unexplainable. From HGD, CDM and its massive first stars, and re-ionization by Pop III...

  13. Understanding Karma Police: The Perceived Plausibility of Noun Compounds as Predicted by Distributional Models of Semantic Representation

    Science.gov (United States)

    Günther, Fritz; Marelli, Marco

    2016-01-01

    Noun compounds, consisting of two nouns (the head and the modifier) that are combined into a single concept, differ in terms of their plausibility: school bus is a more plausible compound than saddle olive. The present study investigates which factors influence the plausibility of attested and novel noun compounds. Distributional Semantic Models (DSMs) are used to obtain formal (vector) representations of word meanings, and compositional methods in DSMs are employed to obtain such representations for noun compounds. From these representations, different plausibility measures are computed. Three of those measures contribute in predicting the plausibility of noun compounds: The relatedness between the meaning of the head noun and the compound (Head Proximity), the relatedness between the meaning of modifier noun and the compound (Modifier Proximity), and the similarity between the head noun and the modifier noun (Constituent Similarity). We find non-linear interactions between Head Proximity and Modifier Proximity, as well as between Modifier Proximity and Constituent Similarity. Furthermore, Constituent Similarity interacts non-linearly with the familiarity with the compound. These results suggest that a compound is perceived as more plausible if it can be categorized as an instance of the category denoted by the head noun, if the contribution of the modifier to the compound meaning is clear but not redundant, and if the constituents are sufficiently similar in cases where this contribution is not clear. Furthermore, compounds are perceived to be more plausible if they are more familiar, but mostly for cases where the relation between the constituents is less clear. PMID:27732599

  14. A primitive cell origin for B-cell precursor ALL?

    Science.gov (United States)

    Cox, C V; Blair, A

    2005-01-01

    A stem cell origin has been described for both acute and chronic myelogenous leukemias. In contrast, childhood B-cell precursor acute lymphoblastic leukemia (ALL) is thought to arise in committed B-lineage cells. Recently described in vitro and in vivo model systems that support the proliferation and expansion of ALL cells have provided new tools to investigate the cellular targets for the origin of this malignancy. Evidence suggests that some subtypes of childhood ALL have a primitive cell origin and share many immunophenotypic characteristics with normal progenitor cells. These leukemic stem cells may be resistant to current therapeutic strategies designed to kill the bulk ALL cell population and subsequent relapses may arise from this population. More precise definition of these ALL stem cells through combined analyses of antigen expression, genetic lesions, and functionality is essential for the development of more effective, targeted therapeutic strategies.

  15. Evolution vs the number of gene copies per primitive cell.

    Science.gov (United States)

    Koch, A L

    1984-01-01

    Computer simulations are presented of the rate at which an advantageous mutant would displace the prototype in a replicating system without an accurate segregation mechanism. If the number of gene copies in the system is indefinitely large, Darwinian evolution is essentially stopped because there is no coupling of phenotype with genotype, i.e., there is no growth advantage to the advantageous gene relative to the prototype and therefore no "survival of the fittest." The inhibition of evolution due to a number of gene copies less than 100 would have been not insurmountable. Although the presence of multiple copies would have allowed replacement by an advantageous mutant, it provided a way for the primitive cell to conserve less immediately useful genes that could evolve into different or more effective genes. This possibility was lost as accurate segregation mechanisms evolved and cells with few copies of each gene, such as modern procaryotes, arose.

  16. Small supratentorial, extraaxial primitive neuroectodermal tumor causing large intracerebral hematoma.

    Science.gov (United States)

    Burkhardt, Jan-Karl; Kockro, Ralf A; Dohmen-Scheufler, Hildegard; Woernle, Christoph M; Bellut, David; Kollias, Spyros; Bertalanffy, Helmut

    2011-01-01

    A 16-year-old boy presented with an unusual case of a supratentorial, extraaxial small round blue cell tumor of the central nervous system, which was most likely a primitive neuroectodermal tumor (PNET). Preoperative computed tomography and magnetic resonance imaging showed a large multistage hematoma in the left central region. Intraoperatively, a small, superficial tumorous lesion was found between the sagittal sinus and a large cortical vein hidden by the hematoma. The histological diagnosis was PNET. This tumor is one of the most aggressive intracerebral tumors, not only in children, so treatment strategies must be early, profound, and interdisciplinary. This case represents an important example of atypical extraaxial appearance of this lesion, which should be considered in the differential diagnosis of cortical or subcortical hemorrhage, since complete resection of this lesion is critical for the successful treatment and outcome.

  17. The CHY representation of tree-level primitive QCD amplitudes

    CERN Document Server

    de la Cruz, Leonardo; Weinzierl, Stefan

    2015-01-01

    In this paper we construct a CHY representation for all tree-level primitive QCD amplitudes. The quarks may be massless or massive. We define a generalised cyclic factor $\\hat{C}(w,z)$ and a generalised permutation invariant function $\\hat{E}(z,p,\\varepsilon)$. The amplitude is then given as a contour integral encircling the solutions of the scattering equations with the product $\\hat{C} \\hat{E}$ as integrand. Equivalently, it is given as a sum over the inequivalent solutions of the scattering equations, where the summand consists of a Jacobian times the product $\\hat{C} \\hat{E}$. This representation separates information: The generalised cyclic factor does not depend on the helicities of the external particles, the generalised permutation invariant function does not depend on the ordering of the external particles.

  18. [Primitive neuroectodermal tumor of kidney : a case report].

    Science.gov (United States)

    Tsutsumi, Naofumi; Sumiyoshi, Takayuki; Okamura, Motohiro; Nakashima, Yoshiharu; Iwamura, Hiroshi; Mitsumori, Kenji; Nishimura, Kazuo; Shintaku, Masayuki; Koyama, Takashi; Matsui, Yusuke; Watanabe, Mitsumasa

    2013-06-01

    A 16-year-old man was referred to our hospital for asymptomatic gross hematuria. The findings of abdominal ultrasonography were normal. A month later, gross hematuria disappeared, and he was not followed after that. A month later, the patient was taken to our hospital in an ambulance for severe back pain and recurring gross hematuria. Computed tomography (CT) revealed a large right renal tumor with tumor thrombus penetrating inside the inferior vena cava. The patient underwent radical nephrectomy and embolectomy. The pathological diagnosis of the tumor was diagnosed as primitive neuroectodermal tumor (PNET) of kidney by immunostaining and gene analysis. We started adjuvant chemotherapy soon after the operation. However, at 10 months after, multiple pulmonary metastases were detected. The patient was treated with salvage chemotherapy, surgery and irradiation therapy as combined modality therapy. Nevertheless, he died 18 months after the diagnosis.

  19. Primitive Neuroectodermal Tumor of the Stomach: A Case Report.

    Science.gov (United States)

    Song, Min Jeong; An, Soyeon; Lee, Seung Soo; Kim, Beom Su; Kim, Jihun

    2016-09-01

    Ewing sarcoma/primitive neuroectodermal tumor (ES/PNET) is a highly aggressive small round cell tumor that mainly occurs in the bone or soft tissue of children or young adults but is extremely rare in the stomach. A 55-year-old man presented with melena and anemia. On endoscopy, an ulcerofungating mass was observed in the high body and total gastrectomy was performed. Histologically, the mass consisted of small round cells with scanty cytoplasm and inconspicuous nucleoli. They often formed perivascular pseudorosettes and multinucleated giant cells were frequently observed. The tumor cells strongly expressed CD99, FLI1, and chromogranin and weakly expressed synaptophysin and CD56. EWS-FLI1 fusion transcript was confirmed by reverse transcription-polymerase chain reaction. ES/PNET is frequently misdiagnosed because of its similarity with small cell carcinoma. Although gastric ES/PNET is very rare, it should be included in differential diagnoses of small round cell tumor in the stomach.

  20. Paravaginal peripheral primitive neuroectodermal tumor: A rare tumor

    Directory of Open Access Journals (Sweden)

    Samrat Dutta

    2011-01-01

    Full Text Available Peripheral primitive neuroectodermal tumor (PNET of the female genital tract, particularly those in the vaginal and paravaginal region, are extremely rare. A 36-year-old woman presented with clinical features similar to that of a case of cervical fibroid. It was only after surgery that the histopathology suggested it to be a malignant round cell tumour and was CD99 positive. She underwent adjuvant chemotherapy with the Ifosfamide and Etoposide alternating with Vincristine, Doxorubicin, and Cyclophosphamide regime and radical radiotherapy. She is disease free at 12 months of follow-up. The importance of immunostaining and adequate histopathology report lies in the fact that the correct diagnosis thus achieved enabled us to manage a rare case of paravaginal PNET with a multimodality approach.

  1. Heterogeneity of extraparenchymal primitive neuroectodermal tumors within the craniospinal axis.

    Directory of Open Access Journals (Sweden)

    M Debiec-Rychter

    2005-02-01

    Full Text Available Four cases of primitive neuroectodermal tumors (PNETs with unusual localization (three intraspinal extramedullary and one pontocerebellar are reviewed. Histologically, they were small round blue cell tumors with diverse patterns. Immunohistochemically, all tumors were positive for at least two neuronal markers, two cases were Mic-2 positive and one showed glial differentiation. The paraffin-embedded tumor specimens were examined by interphase FISH using dual-color probes specific for EWS, HER-2 and BCR loci. Molecular cytogenetic study revealed the presence of EWS rearrangement in two cases and the presence of i(17q in one tumor. Three tumors exhibited 22 disomy and one was 22 polyploid. Extraparenchymal PNETs within craniospinal axis are heterogeneous from the clinical, histological, immunohistochemical and molecular point of view. These PNETs can be of a central or peripheral type. Multidisciplinary approach is of a basic importance in differential diagnosis of such cases.

  2. A simple physical mechanism enables homeostasis in primitive cells

    Science.gov (United States)

    Engelhart, Aaron E.; Adamala, Katarzyna P.; Szostak, Jack W.

    2016-05-01

    The emergence of homeostatic mechanisms that enable maintenance of an intracellular steady state during growth was critical to the advent of cellular life. Here, we show that concentration-dependent reversible binding of short oligonucleotides, of both specific and random sequence, can modulate ribozyme activity. In both cases, catalysis is inhibited at high concentrations, and dilution activates the ribozyme via inhibitor dissociation, thus maintaining near-constant ribozyme specific activity throughout protocell growth. To mimic the result of RNA synthesis within non-growing protocells, we co-encapsulated high concentrations of ribozyme and oligonucleotides within fatty acid vesicles, and ribozyme activity was inhibited. Following vesicle growth, the resulting internal dilution produced ribozyme activation. This simple physical system enables a primitive homeostatic behaviour: the maintenance of constant ribozyme activity per unit volume during protocell volume changes. We suggest that such systems, wherein short oligonucleotides reversibly inhibit functional RNAs, could have preceded sophisticated modern RNA regulatory mechanisms, such as those involving miRNAs.

  3. Plutonium-244 fission xenon in the most primitive meteorites

    Energy Technology Data Exchange (ETDEWEB)

    Kuroda, P.K.; Myers, W.A. (Dept. of Chemical Engineering, Univ. Arkansas, Fayetteville, AR (United States))

    1994-01-01

    The plutonium-244/xenon-136 ages of the Murchison, Murray and Orgueil meteorites have been calculated from the existing xenon isotope data and the uranium contents. The CI carbonaceous chondrite Orgueil, which is considered to be among the most primitive - in the sense of the least altered - sample of the solar system known to man, appears to have started to retain its xenon more than 5,000 million years ago, when the ratio of [sup 244]Pu to [sup 238]U in the solar system was as high as (0.5 [+-] 0.1) (atom/atom) and the CM carbonaceous chondrites Murchison and Murray started to retain their xenon about 4,940 million years ago, when the [sup 244]Pu to [sup 238]U ratio was about 0.17 (atom/atom). (orig.)

  4. A Novel Discovery of Growth Process for Ag Nanowires and Plausible Mechanism

    Directory of Open Access Journals (Sweden)

    Jiejun Zhu

    2016-01-01

    Full Text Available A novel growth process of silver nanowires was revealed by tracing the morphology evolution of Ag nanostructures fabricated by an improved polyol process. A mixture of Ag nanowires and nanoparticles was obtained with the usage of PVP-K25 (MW = 38,000. The products sampled at different reaction time were studied in detail using UV-visible absorption spectra and transmission electron microscopy (TEM. An interesting phenomenon unknown in the past was observed where Ag nanoparticles undergo an important dissolution-recrystallization process and Ag nanowires are formed at the expense of the preformed Ag nanoparticles. A plausible novel growth mechanism for the silver nanowires was proposed.

  5. ‘One of the Challenges that Can Plausibly Be Raised Against Them’?

    DEFF Research Database (Denmark)

    Holtermann, Jakob v. H.

    2017-01-01

    International criminal tribunals (ICTs) are epistemic engines in the sense that they find (or claim to find) factual truths about such past events that qualify as genocide, crimes against humanity and war crimes. The value of this kind of knowledge would seem to be beyond dispute. Yet, in general...... in law is intimately connected to ordinary truth. Truth-finding capacity therefore does belong in legitimacy debates as a challenge that can plausibly be raised against them. This, in turn makes it relevant, in future research, to map, analyse and interrelate the various critiques that have been launched...

  6. A biological plausible Generalized Leaky Integrate-and-Fire neuron model.

    Science.gov (United States)

    Wang, Zhenzhong; Guo, Lilin; Adjouadi, Malek

    2014-01-01

    This study introduces a new Generalized Leaky Integrate-and-Fire (GLIF) neuron model. Unlike Normal Leaky Integrate-and-Fire (NLIF) models, the leaking resistor in the GLIF model equation is assumed to be variable, and an additional term would have the bias current added to the model equation in order to improve the accuracy. Adjusting the parameters defined for the leaking resistor and bias current, a GLIF model could be accurately matched to any Hodgkin-Huxley (HH) model and be able to reproduce plausible biological neuron behaviors.

  7. Higher Data Quality by Online Data-Entry and Automated Plausibility Checks

    Science.gov (United States)

    Pietragalla, Barbara; Sigg, Christian; Güsewell, Sabine; Clot, Bernard

    2014-05-01

    Long-term phenological observations are now recognized as important indicators for climate change impact studies. With the increased need for phenological data, there is also an increased need for higher data quality. Since 1951 MeteoSwiss has been operating a national phenological observation network. Currently the network consists of about 150 active stations observing up to 69 different phenophases. An important aim of a running three years project at MeteoSwiss is a further increase of the quality of the collected data. The higher data quality will be achieved by an automated procedure performing plausibility checks on the data and by online data-entry. Further measures such as intensified observer instructions and collection of more detailed metadata also contribute to a high data quality standard. The plausibility checks include the natural order of the phenophases within a species and also between different species (with regard to possible natural deviation). Additionally it will be checked if the observed date differs by less than two standard deviations from the average for this phenophase at the altitude of the station. A value outside of these limits is not necessarily a false value, since occurrences of extreme values will be beyond these limits. Therefore, within this check of the limits, the timing of the season of the respective year will also be taken into account. In case of an implausible value a comparison with other stations of the same region and sea level is proposed. A further possibility of data quality control could be to model the different phenophases statistically and to use this model for estimating the likelihood of observed values. An overall exploratory data analysis is currently performed providing a solid basis to implement the best possible methods for the plausibility checks. Important advantages of online data-entry are the near real-time availability of the data as well as the avoidance of various kinds of typical mistakes

  8. Exploring discrepancies between quantitative validation results and the geomorphic plausibility of statistical landslide susceptibility maps

    Science.gov (United States)

    Steger, Stefan; Brenning, Alexander; Bell, Rainer; Petschko, Helene; Glade, Thomas

    2016-06-01

    Empirical models are frequently applied to produce landslide susceptibility maps for large areas. Subsequent quantitative validation results are routinely used as the primary criteria to infer the validity and applicability of the final maps or to select one of several models. This study hypothesizes that such direct deductions can be misleading. The main objective was to explore discrepancies between the predictive performance of a landslide susceptibility model and the geomorphic plausibility of subsequent landslide susceptibility maps while a particular emphasis was placed on the influence of incomplete landslide inventories on modelling and validation results. The study was conducted within the Flysch Zone of Lower Austria (1,354 km2) which is known to be highly susceptible to landslides of the slide-type movement. Sixteen susceptibility models were generated by applying two statistical classifiers (logistic regression and generalized additive model) and two machine learning techniques (random forest and support vector machine) separately for two landslide inventories of differing completeness and two predictor sets. The results were validated quantitatively by estimating the area under the receiver operating characteristic curve (AUROC) with single holdout and spatial cross-validation technique. The heuristic evaluation of the geomorphic plausibility of the final results was supported by findings of an exploratory data analysis, an estimation of odds ratios and an evaluation of the spatial structure of the final maps. The results showed that maps generated by different inventories, classifiers and predictors appeared differently while holdout validation revealed similar high predictive performances. Spatial cross-validation proved useful to expose spatially varying inconsistencies of the modelling results while additionally providing evidence for slightly overfitted machine learning-based models. However, the highest predictive performances were obtained for

  9. A biologically plausible transform for visual recognition that is invariant to translation, scale and rotation

    Directory of Open Access Journals (Sweden)

    Pavel eSountsov

    2011-11-01

    Full Text Available Visual object recognition occurs easily despite differences in position, size, and rotation of the object, but the neural mechanisms responsible for this invariance are not known. We have found a set of transforms that achieve invariance in a neurally plausible way. We find that a transform based on local spatial frequency analysis of oriented segments and on logarithmic mapping, when applied twice in an iterative fashion, produces an output image that is unique to the object and that remains constant as the input image is shifted, scaled or rotated.

  10. Primitive cardiac cells from human embryonic stem cells.

    Science.gov (United States)

    Hudson, James; Titmarsh, Drew; Hidalgo, Alejandro; Wolvetang, Ernst; Cooper-White, Justin

    2012-06-10

    Pluripotent stem cell-derived cardiomyocytes are currently being investigated for in vitro human heart models and as potential therapeutics for heart failure. In this study, we have developed a differentiation protocol that minimizes the need for specific human embryonic stem cell (hESC) line optimization. We first reduced the heterogeneity that exists within the starting population of bulk cultured hESCs by using cells adapted to single-cell passaging in a 2-dimensional (2D) culture format. Compared with bulk cultures, single-cell cultures comprised larger fractions of TG30(hi)/OCT4(hi) cells, corresponding to an increased expression of pluripotency markers OCT4 and NANOG, and reduced expression of early lineage-specific markers. A 2D temporal differentiation protocol was then developed, aimed at reducing the inherent heterogeneity and variability of embryoid body-based protocols, with induction of primitive streak cells using bone morphogenetic protein 4 and activin A, followed by cardiogenesis via inhibition of Wnt signaling using the small molecules IWP-4 or IWR-1. IWP-4 treatment resulted in a large percentage of cells expressing low amounts of cardiac myosin heavy chain and expression of early cardiac progenitor markers ISL1 and NKX2-5, thus indicating the production of large numbers of immature cardiomyocytes (~65,000/cm(2) or ~1.5 per input hESC). This protocol was shown to be effective in HES3, H9, and, to a lesser, extent, MEL1 hESC lines. In addition, we observed that IWR-1 induced predominantly atrial myosin light chain (MLC2a) expression, whereas IWP-4 induced expression of both atrial (MLC2a) and ventricular (MLC2v) forms. The intrinsic flexibility and scalability of this 2D protocol mean that the output population of primitive cardiomyocytes will be particularly accessible and useful for the investigation of molecular mechanisms driving terminal cardiomyocyte differentiation, and potentially for the future treatment of heart failure.

  11. Primitive layered gabbros from fast-spreading lower oceanic crust.

    Science.gov (United States)

    Gillis, Kathryn M; Snow, Jonathan E; Klaus, Adam; Abe, Natsue; Adrião, Alden B; Akizawa, Norikatsu; Ceuleneer, Georges; Cheadle, Michael J; Faak, Kathrin; Falloon, Trevor J; Friedman, Sarah A; Godard, Marguerite; Guerin, Gilles; Harigane, Yumiko; Horst, Andrew J; Hoshide, Takashi; Ildefonse, Benoit; Jean, Marlon M; John, Barbara E; Koepke, Juergen; Machi, Sumiaki; Maeda, Jinichiro; Marks, Naomi E; McCaig, Andrew M; Meyer, Romain; Morris, Antony; Nozaka, Toshio; Python, Marie; Saha, Abhishek; Wintsch, Robert P

    2014-01-09

    Three-quarters of the oceanic crust formed at fast-spreading ridges is composed of plutonic rocks whose mineral assemblages, textures and compositions record the history of melt transport and crystallization between the mantle and the sea floor. Despite the importance of these rocks, sampling them in situ is extremely challenging owing to the overlying dykes and lavas. This means that models for understanding the formation of the lower crust are based largely on geophysical studies and ancient analogues (ophiolites) that did not form at typical mid-ocean ridges. Here we describe cored intervals of primitive, modally layered gabbroic rocks from the lower plutonic crust formed at a fast-spreading ridge, sampled by the Integrated Ocean Drilling Program at the Hess Deep rift. Centimetre-scale, modally layered rocks, some of which have a strong layering-parallel foliation, confirm a long-held belief that such rocks are a key constituent of the lower oceanic crust formed at fast-spreading ridges. Geochemical analysis of these primitive lower plutonic rocks--in combination with previous geochemical data for shallow-level plutonic rocks, sheeted dykes and lavas--provides the most completely constrained estimate of the bulk composition of fast-spreading oceanic crust so far. Simple crystallization models using this bulk crustal composition as the parental melt accurately predict the bulk composition of both the lavas and the plutonic rocks. However, the recovered plutonic rocks show early crystallization of orthopyroxene, which is not predicted by current models of melt extraction from the mantle and mid-ocean-ridge basalt differentiation. The simplest explanation of this observation is that compositionally diverse melts are extracted from the mantle and partly crystallize before mixing to produce the more homogeneous magmas that erupt.

  12. The Primitive Material Explorer (PriME) Mission

    Science.gov (United States)

    Cochran, Anita L.; Weaver, H. A.; Science, PriME; Engineering Teams

    2010-10-01

    The Primitive Material Explorer (PriME) Mission is a proposed Discovery mission that will rendezvous with comet 46P/Wirtanen in 2021 in order to 1) clarify the roles played by comets in the formation and evolution of the Solar System and the origin of life; 2) ascertain the bulk physical properties, the surface geology, and the sources of activity in a fresh comet nucleus; and 3) investigate the compositional diversity of primitive material in the Solar System. PriME teams an experienced group of comet scientists (led by PI Anita Cochran and by DPI Harold Weaver) with university and industrial partners. The PriME payload accomplishes the mission objectives with only three instruments. MASPEX (MAss Spectrometer for Planetary EXploration) has higher mass resolution and is more sensitive than any mass spectrometer ever flown. MASPEX will measure D/H in H2O, noble gases, isotopes of many species, and complex molecular compounds to test solar nebula models and the role comets played in delivering water and other biologically important materials throughout the Solar System. The VIS (Visible Imaging System), consisting of a Narrow Angle Camera (NAC) and Wide-Angle Camera (WAC), will constrain the conditions under which the building blocks of the outer Solar System were assembled by measuring key physical properties of the nucleus of 46P/Wirtanen. Using the radio antenna and close flybys of the nucleus, PriME will determine the mass of the nucleus to an accuracy of 1% and the bulk density and average porosity of the nucleus to better than 5%. All spacecraft subsystems have significant planetary flight heritage. The spacecraft is a high-heritage derivative of the Kepler and Deep Impact spacecrafts, compatible with the three launch vehicle families specified in the Discovery Announcement of Opportunity.

  13. Snowball Earth

    OpenAIRE

    2016-01-01

    In the ongoing quest to better understand where life may exist elsewhere in the Universe, important lessons may be gained from our own planet. In particular, much can be learned from planetary glaciation events that Earth suffered ∼600 million years ago, so-called `Snowball Earth' episodes. I begin with an overview of how the climate works. This helps to explain how the ice-albedo feedback effect can destabilise a planet's climate. The process relies on lower temperatures causing more ice to ...

  14. Classification of Graph C*-Algebras with No More than Four Primitive Ideals

    DEFF Research Database (Denmark)

    Eilers, Søren; Restorff, Gunnar; Ruiz, Efren

    2013-01-01

    We describe the status quo of the classification problem of graph C∗-algebras with four primitive ideals or less.......We describe the status quo of the classification problem of graph C∗-algebras with four primitive ideals or less....

  15. Primitive Neuroectodermal Tumor of Mediastinum in an Adult: A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Sung, Young Jae; Kim, Jeung Sook [Dongguk University Ilsan Hospital, Goyang (Korea, Republic of)

    2009-11-15

    A peripheral primitive neuroectodermal tumor (PNET) is a rare and aggressive malignant tumor, which most frequently occurs in children and young adults. The most well described site of origin is the chest wall. We report the case of a primitive neuroectodermal tumor in the anterior mediastinum with unusual CT findings.

  16. The Influence of Primitive Subgroups on the Structure of Finite Groups

    Institute of Scientific and Technical Information of China (English)

    Liu Yu-feng; Du Xian-kun(Communicated)

    2013-01-01

    A subgroup H of a group G is said to be primitive if it is a proper subgroup of the intersection of all subgroups of G containing H as its proper subgroup. The purpose of this note is to go further into the influence of primitive subgroups on the structure of finite groups. Some new results are obtained.

  17. Digital Earth - A sustainable Earth

    Science.gov (United States)

    Mahavir

    2014-02-01

    All life, particularly human, cannot be sustainable, unless complimented with shelter, poverty reduction, provision of basic infrastructure and services, equal opportunities and social justice. Yet, in the context of cities, it is believed that they can accommodate more and more people, endlessly, regardless to their carrying capacity and increasing ecological footprint. The 'inclusion', for bringing more and more people in the purview of development is often limited to social and economic inclusion rather than spatial and ecological inclusion. Economic investment decisions are also not always supported with spatial planning decisions. Most planning for a sustainable Earth, be at a level of rural settlement, city, region, national or Global, fail on the capacity and capability fronts. In India, for example, out of some 8,000 towns and cities, Master Plans exist for only about 1,800. A chapter on sustainability or environment is neither statutorily compulsory nor a norm for these Master Plans. Geospatial technologies including Remote Sensing, GIS, Indian National Spatial Data Infrastructure (NSDI), Indian National Urban Information Systems (NUIS), Indian Environmental Information System (ENVIS), and Indian National GIS (NGIS), etc. have potential to map, analyse, visualize and take sustainable developmental decisions based on participatory social, economic and social inclusion. Sustainable Earth, at all scales, is a logical and natural outcome of a digitally mapped, conceived and planned Earth. Digital Earth, in fact, itself offers a platform to dovetail the ecological, social and economic considerations in transforming it into a sustainable Earth.

  18. Isotopic evidence of Cr partitioning into Earth's core.

    Science.gov (United States)

    Moynier, Frederic; Yin, Qing-Zhu; Schauble, Edwin

    2011-03-18

    The distribution of chemical elements in primitive meteorites (chondrites), as building blocks of terrestrial planets, provides insight into the formation and early differentiation of Earth. The processes that resulted in the depletion of some elements [such as chromium (Cr)] in the bulk silicate Earth relative to chondrites, however, remain debated between leading candidate causes: volatility versus core partitioning. We show through high-precision measurements of Cr stable isotopes in a range of meteorites, which deviate by up to ~0.4 per mil from those of the bulk silicate Earth, that Cr depletion resulted from its partitioning into Earth's core, with a preferential enrichment in light isotopes. Ab initio calculations suggest that the isotopic signature was established at mid-mantle magma ocean depth as Earth accreted planetary embryos and progressively became more oxidized.

  19. Primitive neuroectodermal tumor of the kidney in a young male: Case report and review of literature.

    Science.gov (United States)

    Patnaik, Nivedita; Mishra, Kiran; Saini, Pradeep; Agarwal, Nitin

    2015-01-01

    Primitive neuroectodermal tumor of the kidney is a rare tumor. A total of approximately 79 primary renal cases have been reported to date. Primitive neuroectodermal tumors occur preferentially in the soft-tissues of the paravertebral region and chest wall, less frequently in extremities, with a slight male predominance. We report a case of primitive neuroectodermal tumor of the kidney in a 17-year-old male with a pre-operative diagnosis of renal cell carcinoma-stage 4. The patient underwent radical nephrectomy and histopathological examination revealed a highly aggressive tumor of monotonous sheets of round cells with focal areas of rosette formations and high mitotic rate with Ki67 index of 25-30%. Tumor cells were positive for CD 99 confirming the diagnosis of primitive neuroectodermal tumor. Primitive neuroectodermal tumor of the kidney needs to be kept in mind as a differential diagnosis in young adults presenting with a large kidney mass.

  20. A swarm intelligence framework for reconstructing gene networks: searching for biologically plausible architectures.

    Science.gov (United States)

    Kentzoglanakis, Kyriakos; Poole, Matthew

    2012-01-01

    In this paper, we investigate the problem of reverse engineering the topology of gene regulatory networks from temporal gene expression data. We adopt a computational intelligence approach comprising swarm intelligence techniques, namely particle swarm optimization (PSO) and ant colony optimization (ACO). In addition, the recurrent neural network (RNN) formalism is employed for modeling the dynamical behavior of gene regulatory systems. More specifically, ACO is used for searching the discrete space of network architectures and PSO for searching the corresponding continuous space of RNN model parameters. We propose a novel solution construction process in the context of ACO for generating biologically plausible candidate architectures. The objective is to concentrate the search effort into areas of the structure space that contain architectures which are feasible in terms of their topological resemblance to real-world networks. The proposed framework is initially applied to the reconstruction of a small artificial network that has previously been studied in the context of gene network reverse engineering. Subsequently, we consider an artificial data set with added noise for reconstructing a subnetwork of the genetic interaction network of S. cerevisiae (yeast). Finally, the framework is applied to a real-world data set for reverse engineering the SOS response system of the bacterium Escherichia coli. Results demonstrate the relative advantage of utilizing problem-specific knowledge regarding biologically plausible structural properties of gene networks over conducting a problem-agnostic search in the vast space of network architectures.

  1. The Sarrazin effect: the presence of absurd statements in conspiracy theories makes canonical information less plausible.

    Science.gov (United States)

    Raab, Marius Hans; Auer, Nikolas; Ortlieb, Stefan A; Carbon, Claus-Christian

    2013-01-01

    Reptile prime ministers and flying Nazi saucers-extreme and sometimes off-wall conclusion are typical ingredients of conspiracy theories. While individual differences are a common research topic concerning conspiracy theories, the role of extreme statements in the process of acquiring and passing on conspiratorial stories has not been regarded in an experimental design so far. We identified six morphological components of conspiracy theories empirically. On the basis of these content categories a set of narrative elements for a 9/11 story was compiled. These elements varied systematically in terms of conspiratorial allegation, i.e., they contained official statements concerning the events of 9/11, statements alleging to a conspiracy limited in time and space as well as extreme statements indicating an all-encompassing cover-up. Using the method of narrative construction, 30 people were given a set of cards with these statements and asked to construct the course of events of 9/11 they deem most plausible. When extreme statements were present in the set, the resulting stories were more conspiratorial; the number of official statements included in the narrative dropped significantly, whereas the self-assessment of the story's plausibility did not differ between conditions. This indicates that blatant statements in a pool of information foster the synthesis of conspiracy theories on an individual level. By relating these findings to one of Germany's most successful (and controversial) non-fiction books, we refer to the real-world dangers of this effect.

  2. Physical Characterization and Origin of Binary Near-Earth Asteroid (175706) 1996 FG3

    NARCIS (Netherlands)

    Walsh, Kevin J.; Delbo', Marco; Mueller, Michael; Binzel, Richard P.; DeMeo, Francesca E.

    2012-01-01

    The near-Earth asteroid (NEA) (175706) 1996 FG3 is a particularly interesting spacecraft target: a binary asteroid with a low-Δv heliocentric orbit. The orbit of its satellite has provided valuable information about its mass density while its albedo and colors suggest it is primitive or part of the

  3. Physical Characterization and Origin of Binary Near-Earth Asteroid (175706) 1996 FG3

    NARCIS (Netherlands)

    Walsh, Kevin J.; Delbo', Marco; Mueller, Michael; Binzel, Richard P.; DeMeo, Francesca E.

    2012-01-01

    The near-Earth asteroid (NEA) (175706) 1996 FG3 is a particularly interesting spacecraft target: a binary asteroid with a low-Δv heliocentric orbit. The orbit of its satellite has provided valuable information about its mass density while its albedo and colors suggest it is primitive or part of the

  4. Mission to Very Early Earth

    Energy Technology Data Exchange (ETDEWEB)

    Hutcheon, I D; Weber, P K; Fallon, S J; Smith, J B; Aleon, J; Ryerson, F J; Harrison, T M; Cavosie, A J; Valley, J W

    2007-03-13

    The Hadean Earth is often viewed as an inhospitable and, perhaps, unlikely setting for the rise of primordial life. However, carbonaceous materials supplied by accreting meteorites and sources of chemical energy similar to those fueling life around modern deep-sea volcanic vents would have been present in abundance. More questionable are two other essential ingredients for life - liquid water and clement temperatures. Did the Hadean Earth possess a hydrosphere and temperate climate compatible with the initiation of biologic activity? If so, the popular model of an excessively hot planetary surface characterized by a basaltic crust, devoid of continental material is invalid. Similarly, establishment of an Hadean hydrosphere prior to the cessation of heavy asteroid bombardment may mean that primitive life could have evolved and then been extinguished, only to rise again. The most effective means of determining the environmental conditions on this young planet is through geochemical analysis of samples retrieved from the Early Earth. While rocks older than 4 billion years (4 Ga) have not been found, individual zircon grains, the detritus of rocks long since eroded away, have been identified with ages as old as 4.4 Ga - only {approx}160 million years younger than the Earth itself. If we can use the geochemical information contained in these unique samples to infer the nature of their source rocks and the processes that formed them, we can place constraints on the conditions prevailing at the Earth's surface shortly after formation. This project utilizes a combined analytical and experimental approach to gather the necessary geochemical data to determine the parameters required to relate the zircons to their parent materials. Mission to Early Earth involves dating, isotopic and chemical analyses of mineral and melt inclusions within zircons and of the zircons themselves. The major experimental activity at LLNL focused on the partitioning of trace elements between

  5. Identification of Genes Expressed in the Migrating Primitive Myeloid Lineage of Xenopus laevis

    Science.gov (United States)

    Agricola, Zachary N.; Jagpal, Amrita K.; Allbee, Andrew W.; Prewitt, Allison R.; Shifley, Emily T.; Rankin, Scott A.; Zorn, Aaron M.; Kenny, Alan P.

    2017-01-01

    Background During primitive hematopoiesis in Xenopus, cebpa and spib expressing myeloid cells emerge from the anterior ventral blood island. Primitive myeloid cells migrate throughout the embryo and are critical for immunity, healing, and development. Although definitive hematopoiesis has been studied extensively, molecular mechanisms leading to the migration of primitive myelocytes remain poorly understood. We hypothesized these cells have specific extracellular matrix modifying and cell motility gene expression. Results In situ hybridization screens of transcripts expressed in Xenopus foregut mesendoderm at stage 23 identified seven genes with restricted expression in primitive myeloid cells: destrin; coronin actin binding protein, 1a; formin-like 1; ADAM metallopeptidase domain 28; cathepsin S; tissue inhibitor of metalloproteinase-1; and protein tyrosine phosphatase nonreceptor 6. A detailed in situ hybridization analysis revealed these genes are initially expressed in the aVBI but become dispersed throughout the embryo as the primitive myeloid cells become migratory, similar to known myeloid markers. Morpholino-mediated loss-of-function and mRNA-mediated gain-of-function studies revealed the identified genes are downstream of Spib.a and Cebpa, key transcriptional regulators of the myeloid lineage. Conclusions We have identified genes specifically expressed in migratory primitive myeloid progenitors, providing tools to study how different gene networks operate in these primitive myelocytes during development and immunity. PMID:26264370

  6. A neurophysiologically plausible population code model for feature integration explains visual crowding.

    Directory of Open Access Journals (Sweden)

    Ronald van den Berg

    2010-01-01

    Full Text Available An object in the peripheral visual field is more difficult to recognize when surrounded by other objects. This phenomenon is called "crowding". Crowding places a fundamental constraint on human vision that limits performance on numerous tasks. It has been suggested that crowding results from spatial feature integration necessary for object recognition. However, in the absence of convincing models, this theory has remained controversial. Here, we present a quantitative and physiologically plausible model for spatial integration of orientation signals, based on the principles of population coding. Using simulations, we demonstrate that this model coherently accounts for fundamental properties of crowding, including critical spacing, "compulsory averaging", and a foveal-peripheral anisotropy. Moreover, we show that the model predicts increased responses to correlated visual stimuli. Altogether, these results suggest that crowding has little immediate bearing on object recognition but is a by-product of a general, elementary integration mechanism in early vision aimed at improving signal quality.

  7. A neurophysiologically plausible population code model for feature integration explains visual crowding.

    Science.gov (United States)

    van den Berg, Ronald; Roerdink, Jos B T M; Cornelissen, Frans W

    2010-01-22

    An object in the peripheral visual field is more difficult to recognize when surrounded by other objects. This phenomenon is called "crowding". Crowding places a fundamental constraint on human vision that limits performance on numerous tasks. It has been suggested that crowding results from spatial feature integration necessary for object recognition. However, in the absence of convincing models, this theory has remained controversial. Here, we present a quantitative and physiologically plausible model for spatial integration of orientation signals, based on the principles of population coding. Using simulations, we demonstrate that this model coherently accounts for fundamental properties of crowding, including critical spacing, "compulsory averaging", and a foveal-peripheral anisotropy. Moreover, we show that the model predicts increased responses to correlated visual stimuli. Altogether, these results suggest that crowding has little immediate bearing on object recognition but is a by-product of a general, elementary integration mechanism in early vision aimed at improving signal quality.

  8. Quantum theory as plausible reasoning applied to data obtained by robust experiments.

    Science.gov (United States)

    De Raedt, H; Katsnelson, M I; Michielsen, K

    2016-05-28

    We review recent work that employs the framework of logical inference to establish a bridge between data gathered through experiments and their objective description in terms of human-made concepts. It is shown that logical inference applied to experiments for which the observed events are independent and for which the frequency distribution of these events is robust with respect to small changes of the conditions under which the experiments are carried out yields, without introducing any concept of quantum theory, the quantum theoretical description in terms of the Schrödinger or the Pauli equation, the Stern-Gerlach or Einstein-Podolsky-Rosen-Bohm experiments. The extraordinary descriptive power of quantum theory then follows from the fact that it is plausible reasoning, that is common sense, applied to reproducible and robust experimental data.

  9. Plausible families of compact objects with a Non Local Equation of State

    CERN Document Server

    Hernández, H

    2012-01-01

    We investigate the plausibility of some models emerging from an algorithm devised to generate a one-parameter family of interior solutions for the Einstein equations. It is explored how their physical variables change as the family-parameter varies. The models studied correspond to anisotropic spherical matter configurations having a non local equation of state. This particular type of equation of state with no causality problems provides, at a given point, the radial pressure not only as a function of the density but as a functional of the enclosed matter distribution. We have found that there are several model-independent tendencies as the parameter increases: the equation of state tends to be stiffer and the total mass becomes half of its external radius. Profiting from the concept of cracking of materials in General Relativity, we obtain that those models become more stable as the family parameter increases.

  10. Signature of Plausible Accreting Supermassive Black Holes in Mrk 261/262 and Mrk 266

    Directory of Open Access Journals (Sweden)

    Gagik Ter-Kazarian

    2013-01-01

    Full Text Available We address the neutrino radiation of plausible accreting supermassive black holes closely linking to the 5 nuclear components of galaxy samples of Mrk 261/262 and Mrk 266. We predict a time delay before neutrino emission of the same scale as the age of the Universe. The ultrahigh energy neutrinos are produced in superdense protomatter medium via simple (quark or pionic reactions or modified URCA processes (G. Gamow was inspired to name the process URCA after the name of a casino in Rio de Janeiro. The resulting neutrino fluxes for quark reactions are ranging from to , where is the opening parameter. For pionic and modified URCA reactions, the fluxes are and , respectively. These fluxes are highly beamed along the plane of accretion disk, peaked at ultrahigh energies, and collimated in smaller opening angle .

  11. Plausible role of nanoparticle contamination in the synthesis and properties of organic electronic materials

    Science.gov (United States)

    Ananikov, Valentine P.

    2016-12-01

    Traceless transition metal catalysis (Pd, Ni, Cu, etc.) is very difficult to achieve. Metal contamination in the synthesized products is unavoidable and the most important questions are: How to control metal impurities? What amount of metal impurities can be tolerated? What is the influence of metal impurities? In this brief review, the plausible origins of nanoparticle contamination are discussed in the framework of catalytic synthesis of organic electronic materials. Key factors responsible for increasing the probability of contamination are considered from the point of view of catalytic reaction mechanisms. The purity of the catalyst may greatly affect the molecular weight of a polymer, reaction yield, selectivity and several other parameters. Metal contamination in the final polymeric products may induce some changes in the electric conductivity, charge transport properties, photovoltaic performance and other important parameters.

  12. Complex adaptive HIV/AIDS risk reduction: Plausible implications from findings in Limpopo Province, South Africa.

    Science.gov (United States)

    Burman, Chris J; Aphane, Marota A

    2016-05-16

    This article emphasises that when working with complex adaptive systems it is possible to stimulate new social practices and/or cognitive perspectives that contribute to risk reduction, associated with reducing aggregate community viral loads. The process of achieving this is highly participatory and is methodologically possible because evidence of 'attractors' that influence the social practices can be identified using qualitative research techniques. Using findings from Limpopo Province, South Africa, we argue that working with 'wellness attractors' and increasing their presence within the HIV/AIDS landscape could influence aggregate community viral loads. While the analysis that is presented is unconventional, it is plausible that this perspective may hold potential to develop a biosocial response - which the Joint United Nations Programme on HIV and AIDS (UNAIDS) has called for - that reinforces the biomedical opportunities that are now available to achieve the ambition of ending AIDS by 2030.

  13. Reciprocity-based reasons for benefiting research participants: most fail, the most plausible is problematic.

    Science.gov (United States)

    Sofaer, Neema

    2014-11-01

    A common reason for giving research participants post-trial access (PTA) to the trial intervention appeals to reciprocity, the principle, stated most generally, that if one person benefits a second, the second should reciprocate: benefit the first in return. Many authors consider it obvious that reciprocity supports PTA. Yet their reciprocity principles differ, with many authors apparently unaware of alternative versions. This article is the first to gather the range of reciprocity principles. It finds that: (1) most are false. (2) The most plausible principle, which is also problematic, applies only when participants experience significant net risks or burdens. (3) Seldom does reciprocity support PTA for participants or give researchers stronger reason to benefit participants than equally needy non-participants. (4) Reciprocity fails to explain the common view that it is bad when participants in a successful trial have benefited from the trial intervention but lack PTA to it.

  14. Oxidation of cefazolin by potassium permanganate: Transformation products and plausible pathways.

    Science.gov (United States)

    Li, Liping; Wei, Dongbin; Wei, Guohua; Du, Yuguo

    2016-04-01

    Cefazolin was demonstrated to exert high reactivity toward permanganate (Mn(VII)), a common oxidant in water pre-oxidation treatment. In this study, five transformation products were found to be classified into three categories according to the contained characteristic functional groups: three (di-)sulfoxide products, one sulfone product and one di-ketone product. Products analyses showed that two kinds of reactions including oxidation of thioether and the cleavage of unsaturated CC double bond occurred during transformation of cefazolin by Mn(VII). Subsequently, the plausible transformation pathways under different pH conditions were proposed based on the identified products and chemical reaction principles. More importantly, the simulation with real surface water matrix indicated that the proposed transformation pathways of cefazolin could be replayed in real water treatment practices.

  15. Plausible authentication of manuka honey and related products by measuring leptosperin with methyl syringate.

    Science.gov (United States)

    Kato, Yoji; Fujinaka, Rie; Ishisaka, Akari; Nitta, Yoko; Kitamoto, Noritoshi; Takimoto, Yosuke

    2014-07-01

    Manuka honey, obtained from Leptospermum scoparium flowers in New Zealand, has strong antibacterial properties. In this study, plausible authentication of the manuka honey was inspected by measuring leptosperin, methyl syringate 4-O-β-D-gentiobiose, along with methyl syringate. Despite a gradual decrease in methyl syringate content over 30 days at 50 °C, even at moderate 37 °C, leptosperin remained stable. A considerable correlation between nonperoxide antibacterial activity and leptosperin content was observed in 20 certified manuka honey samples. Leptosperin and methyl syringate in manuka honey and related products were analyzed using HPLC connected with mass spectrometry. One noncertified brand displayed significant variations in the leptosperin and methyl syringate contents between two samples obtained from different regions. Therefore, certification is clearly required to protect consumers from disguised and/or low-quality honey. Because leptosperin is stable during storage and specific to manuka honey, its measurement may be applicable for manuka honey authentication.

  16. Evaluation and integration of cancer gene classifiers: identification and ranking of plausible drivers.

    Science.gov (United States)

    Liu, Yang; Tian, Feng; Hu, Zhenjun; DeLisi, Charles

    2015-05-11

    The number of mutated genes in cancer cells is far larger than the number of mutations that drive cancer. The difficulty this creates for identifying relevant alterations has stimulated the development of various computational approaches to distinguishing drivers from bystanders. We develop and apply an ensemble classifier (EC) machine learning method, which integrates 10 classifiers that are publically available, and apply it to breast and ovarian cancer. In particular we find the following: (1) Using both standard and non-standard metrics, EC almost always outperforms single method classifiers, often by wide margins. (2) Of the 50 highest ranked genes for breast (ovarian) cancer, 34 (30) are associated with other cancers in either the OMIM, CGC or NCG database (P plausible. Biological implications are briefly discussed. Source codes and detailed results are available at http://www.visantnet.org/misi/driver_integration.zip.

  17. Probability, plausibility, and adequacy evaluations of the Oriente Study demonstrate that supplementation improved child growth.

    Science.gov (United States)

    Habicht, Jean-Pierre; Martorell, Reynaldo

    2010-02-01

    This article presents evidence that the high-nutrient supplement in the Oriente study (Atole) improved child growth. The evidence is presented at 4 levels. There was a causal effect of the intervention on child length, as assessed by probability analyses of the randomized, controlled trial (P < 0.05). The plausibility analyses, which included an examination of wasting, showed that the nutritional impact was due to the Atole, especially in those who were <3 y old and who suffered from diarrhea. The adequacy analyses revealed excellent biological efficacy of the Atole at the individual level. At the level of the whole population, the efficacy of impact was much less, because many children did not participate fully in the supplementation program. The external validity of the biological impact is likely to be good for populations with similar diets and medical care.

  18. The Sarrazin effect: the presence of absurd statements in conspiracy theories makes canonical information less plausible

    Directory of Open Access Journals (Sweden)

    Marius Hans Raab

    2013-07-01

    Full Text Available Reptile prime ministers and flying Nazi saucers—extreme and sometimes off-wall conclusion are common ingredients of conspiracy theories. While individual differences are a common research topic concerning conspiracy theories, the role of extreme statements in the process of acquiring and passing on conspiratorial stories has not been regarded in an experimental design so far. We identified six morphological components of conspiracy theories empirically. On the basis of these content categories a set of narrative elements for a 9/11 story was compiled. These elements varied systematically in terms of conspiratorial allegation, i.e., they contained official statements concerning the events of 9/11, statements alleging to a conspiracy limited in time and space as well as extreme statements indicating an all-encompassing cover-up. Using the method of narrative construction, 30 people were given a set of cards with these statements and asked to construct the course of events of 9/11 they deem most plausible. When extreme statements were present in the set, the resulting stories were more conspiratorial; the number of official statements included in the narrative dropped significantly, whereas the self-assessment of the story’s plausibility did not differ between conditions. This indicates that blatant statements in a pool of information foster the synthesis of conspiracy theories on an individual level. By relating these findings to one of Germany’s most successful (and controversial non-fiction books, we refer to the real-world dangers of this effect.

  19. Preventing Real-Time Packet Classification Using Cryptographic Primitives

    Directory of Open Access Journals (Sweden)

    N.Vasumathi

    2014-03-01

    Full Text Available Jamming attacks are especially harmful when ensuring the dependability of wireless communication. Typically, jamming has been addressed under an external threat model. Adversaries with internal knowledge of protocol specifications and network secrets can launch low-effort jamming attacks that are difficult to detect and counter. The problem of selective jamming attacks in wireless networks is addressed in this work. In these attacks, the adversary is active only for a short period of time, specifically targeting messages of high importance. The advantages of selective jamming in terms of network performance degradation and adversary effort is illustrated by presenting two case studies; one is selective attack on TCP and another is on routing. The selective jamming attacks can be launched by performing real-time packet classification at the physical layer. To avoid these attacks, four schemes are developed such as All Or Nothing Transformation-Hiding Scheme (AONT-HS - pseudo message is added with message before transformation and encryption, Strong Hiding Commitment Scheme(SHCS - off-the-shelf symmetric encryption is done, Puzzle Based Hiding Scheme(PBHS- time lock and hash puzzle and Nonce based Authenticated Encryption Scheme(N-AES-Nonce is used for encryption, that prevent real-time packet classification by combining cryptographic primitives with physical-layer attributes.

  20. Towards a quantum field theory of primitive string fields

    CERN Document Server

    Ruehl, Werner

    2010-01-01

    We denote generating functions of massless even higher spin fields "primitive string fields" (PSF's). In an introduction we present the necessary definitions and derive propagators and currents of these PDF's on flat space. Their off-shell cubic interaction can be derived after all off-shell cubic interactions of triplets of higher spin fields have become known [2],[3]. Then we discuss four-point functions of any quartet of PSF's. In subsequent sections we exploit the fact that higher spin field theories in $AdS_{d+1}$ are determined by AdS/CFT correspondence from universality classes of critical systems in $d$ dimensional flat spaces. The O(N) invariant sectors of the O(N) vector models for $1\\leq N \\leq \\infty$ play for us the role of "standard models", for varying $N$, they contain e.g. the Ising model for N=1 and the spherical model for $N=\\infty$. A formula for the masses squared that break gauge symmetry for these O(N) classes is presented for d = 3. For the PSF on $AdS$ space it is shown that it can be...

  1. [Case of primitive neuroectodermal tumor of the kidney].

    Science.gov (United States)

    Ueno, Yoko; Ishikawa, Masakuni; Tsuruta, Takashi; Wajiki, Masahisa

    2008-03-01

    A 28-year-old woman presented with right flank pain. A large, firm, fixed mass was palpable in the right side of the abdomen. Computed tomography revealed a solid mass of the right kidney with extension into the renal vein and inferior vena cava. The patient underwent right radical nephrectomy with en bloc resection of the inferior vena cava containing tumor thrombus and right adrenalectomy. Histologically the tumor consisted of small tumor cells with rosette formation. Immunohistochemical staining was positive for CD99 and NSE. Analysis with polymerase chain reaction (PCR) demonstrated the EWS/FLI1 fusion products resulting from a chromosomal translocation. These findings were consistent with primary renal primitive neuroectodermal tumor (PNET). Two months after surgery, multiple lung, liver and lymph node metastases were found. The patient received 2 cycles of chemotherapy with cisplatin, ifosfamide, etoposide, resulting in a partial remission. She subsequently received 1 cycle chemotherapy with paclitaxel and carboplatin, resulting in no response. The metastatic lung and liver diseases progressed and she died 5 months after diagnosis.

  2. Polycomb enables primitive endoderm lineage priming in embryonic stem cells

    Science.gov (United States)

    Illingworth, Robert S; Hölzenspies, Jurriaan J; Roske, Fabian V; Bickmore, Wendy A; Brickman, Joshua M

    2016-01-01

    Mouse embryonic stem cells (ESCs), like the blastocyst from which they are derived, contain precursors of the epiblast (Epi) and primitive endoderm (PrEn) lineages. While transient in vivo, these precursor populations readily interconvert in vitro. We show that altered transcription is the driver of these coordinated changes, known as lineage priming, in a process that exploits novel polycomb activities. We find that intragenic levels of the polycomb mark H3K27me3 anti-correlate with changes in transcription, irrespective of the gene’s developmental trajectory or identity as a polycomb target. In contrast, promoter proximal H3K27me3 is markedly higher for PrEn priming genes. Consequently, depletion of this modification stimulates the degree to which ESCs are primed towards PrEn when challenged to differentiate, but has little effect on gene expression in self-renewing ESC culture. These observations link polycomb with dynamic changes in transcription and stalled lineage commitment, allowing cells to explore alternative choices prior to a definitive decision. DOI: http://dx.doi.org/10.7554/eLife.14926.001 PMID:27723457

  3. Rapid world modeling: Fitting range data to geometric primitives

    Energy Technology Data Exchange (ETDEWEB)

    Feddema, J.; Little, C.

    1996-12-31

    For the past seven years, Sandia National Laboratories has been active in the development of robotic systems to help remediate DOE`s waste sites and decommissioned facilities. Some of these facilities have high levels of radioactivity which prevent manual clean-up. Tele-operated and autonomous robotic systems have been envisioned as the only suitable means of removing the radioactive elements. World modeling is defined as the process of creating a numerical geometric model of a real world environment or workspace. This model is often used in robotics to plan robot motions which perform a task while avoiding obstacles. In many applications where the world model does not exist ahead of time, structured lighting, laser range finders, and even acoustical sensors have been used to create three dimensional maps of the environment. These maps consist of thousands of range points which are difficult to handle and interpret. This paper presents a least squares technique for fitting range data to planar and quadric surfaces, including cylinders and ellipsoids. Once fit to these primitive surfaces, the amount of data associated with a surface is greatly reduced up to three orders of magnitude, thus allowing for more rapid handling and analysis of world data.

  4. Primitive off-rift basalts from Iceland and Jan Mayen

    DEFF Research Database (Denmark)

    Debaille, Vinciane; Trønnes, Reidar G.; Brandon, Alan D.

    2009-01-01

    and appear to be contaminated at a shallow level. The 187Os/188Os ratios in the remaining lavas with >30 ppt Os (n = 17) range between 0.12117 and 0.13324. These values are surprisingly low for oceanic island basalts and include some samples that are less than putative present-day primitive upper mantle (PUM...... with 187Os/188Os of 0.1296). These low 187Os/188Os preclude significant shallow-level contamination from oceanic crust. The 187Os/188Os ratios for Jan Mayen lavas are less than PUM, severely limiting the presence of any continental crust in their mantle source. A positive correlation between 143Nd/144Nd......-members. One end-member, characterized in particular by its unradiogenic 187Os/188Os and 143Nd/144Nd, low 3He/4He and high 87Sr/86Sr, is represented by subcontinental lithospheric mantle stranded and disseminated in the upper mantle during the opening of the Atlantic Ocean. The second end-member corresponds...

  5. Conflict and After: Primitive Accumulation, Hegemonic Formation and Democratic Deepening

    Directory of Open Access Journals (Sweden)

    David Moore

    2015-04-01

    Full Text Available Thinking about war and its aftermath through the lenses of some classical political economy and political ‘science’ may cast fresh light on the protracted relationship of war and development. Karl Marx’s idea of primitive accumulation warns us that ‘becoming capitalist’ is inherently violent. Max Weber’s notion of states’ monopoly over force is worth contemplation even as these organisations simultaneously emerge and fade away. Antonio Gramsci helps us grapple with the dialectic of coercion and consent whilst these processes unfold amidst universal desires for deepening democracy – while its dreams fade into nightmares in a new conjuncture of fear. This paper, prepared for Colombo’s Centre for Policy Analysis and the Secure Livelihoods Research Consortium’s conference ‘Challenges of Post-War Development in Asia and Africa’ of 1 to 3 September 2014, also takes brief forays into some southern African empirical referents to these formulations to further illustrate their complexities and the complications of implementing productive peace in the interstices of the drawn out crises of capitalism’s initial stages in the ‘third world.’

  6. Three boys and their stories: atypical eating and primitive relations.

    Science.gov (United States)

    Escosteguy Carneiro, Maria Inês Neuenschwander

    2008-12-01

    Eating disorders of whatever category, especially the most severe ones such as anorexia or bulimia, are often considered typical of the female sex. While this is correct concerning these two disorders, I suggest that there are other eating disorders that are more frequent among boys, especially the ones concerning atypical relations to food, notwithstanding the evidence that the already very well-known syndromes of bulimia and anorexia are also gaining ground among males. However, similar, unspecified eating disorders do not seem to occur so often among girls. Clinical data from my private practice should be taken for granted considering these matters, since I do not yet have statistical data to back up my thesis. In examples from three clinical cases involving boys and one female vignette, I shall attempt to establish a relation between eating disorders and primitive relations with men and women. This relation goes well beyond the oft-cited 'contemporary' causes of eating disorders. In addition, I shall situate these differences among symptoms of both sexes and relate them to impasses in different stages of emotional development, as well as to the extent to which girls' identification with their mother's sex can influence their acquisition of eating disorders.

  7. Primitive neuroectodermal tumor of adrenal: clinical presentation and outcomes.

    Science.gov (United States)

    Dutta, Deep; Shivaprasad, K S; Das, Ram Narayan; Ghosh, Sujoy; Chowdhury, Subhankar

    2013-01-01

    Primitive neuroectodermal tumor (PNET) of adrenal is an extremely rare tumor of neural crest origin. A nonfunctional left adrenal mass (14.6 × 10.5 × 10.0 cm) on computed tomography (CT) was detected in a 40-year-old lady with abdominal pain, swelling, and left pleural effusion. She underwent left adrenalectomy and left nephrectomy with retroperitoneal resection. Histopathology revealed sheets and nest of oval tumor cells with hyperchromatic nuclei, prominent nucleoli, scanty cytoplasm, brisk mitotic activity, necrosis, lymphovascular invasion, capsular invasion, and extension to the surrounding muscles; staining positive for Mic-2 (CD-99 antigen), vimentin, synaptophysin, and Melan-A. Thoracocentesis, pleural fluid study, and pleural biopsy did not show metastasis. She responded well to vincristine, adriamycin, and cyclophosphamide followed by ifosfamide and etoposide (IE). This is the first report of adrenal peripheral PNET (pPNET) from India. This report intends to highlight that pPNET should be suspected in a patient presenting with huge nonfunctional adrenal mass which may be confused with adrenocortical carcinoma.

  8. Primitive Neuroectodermal Tumor of the Liver: A Case Report

    Directory of Open Access Journals (Sweden)

    Eduardo Cambruzzi

    2011-01-01

    Full Text Available Primary liver sarcomas represent a rare group of neoplasias, with angiosarcoma being the most common histological type. Primitive neuroectodermal tumor (PNET represents a high malignant neoplasia that usually affects the central nervous system and soft tissues. An 18-year-old male patient was admitted with clinical complains of pain in the right upper abdominal quadrant. The clinical evaluation revealed a solid mass in the right hepatic lobe. On the gross examination of the resected liver specimen, the right lobe of the liver was replaced by a yellow-red solid mass measuring 21 cm in its largest dimension. On the histopathology, a tumor composed of small round blue cells with little cytoplasm and round nuclei was identified. The lesion revealed positive immunoexpression for vimentin and CD99 and negative immunostaining for desmin, CD45, cytokeratin, and neuroblastoma protein, suggesting, then, the diagnosis of PNET. Although it is an unusual tumor, it should be considered in the differential diagnosis of liver masses, especially in young patients.

  9. Primary Ewing Sarcoma/Primitive Neuroectodermal Tumor of the Stomach

    Directory of Open Access Journals (Sweden)

    Safi Khuri

    2016-11-01

    Full Text Available Ewing sarcoma/primitive neuroectodermal tumor (ES/PNET is a tumor of small round cells arising in skeletal tissues. These tumors rarely arise in the stomach. We present a 31-year-old healthy female patient who was admitted to our surgical ward due to upper gastrointestinal hemorrhage. Upper endoscopy revealed a large ulcerated bleeding mass originating from the lesser curvature. Biopsy revealed tumor cell immunoreactivity positive for CD99, vimentin, and Ki67 (an index of proliferation. These findings were compatible with gastric ES/PNET. The fluorescence in situ hybridization analysis result for the EWSR1 gene rearrangement (11: 22 translocation was positive. The patient refused neoadjuvant treatment and thus underwent an operation during which a mass at the lesser curvature of the stomach was found. The mass was adhering to the pancreatic tail and to the mesentery of the transverse and descending colon. Total gastrectomy, distal pancreatectomy, splenectomy, and left adrenalectomy were done. The patient refused adjuvant treatment. She is free of disease 3 years after surgery.

  10. Primitive neuroectodermal tumor of adrenal: Clinical presentation and outcomes

    Directory of Open Access Journals (Sweden)

    Deep Dutta

    2013-01-01

    Full Text Available Primitive neuroectodermal tumor (PNET of adrenal is an extremely rare tumor of neural crest origin. A nonfunctional left adrenal mass (14.6 × 10.5 × 10.0 cm on computed tomography (CT was detected in a 40-year-old lady with abdominal pain, swelling, and left pleural effusion. She underwent left adrenalectomy and left nephrectomy with retroperitoneal resection. Histopathology revealed sheets and nest of oval tumor cells with hyperchromatic nuclei, prominent nucleoli, scanty cytoplasm, brisk mitotic activity, necrosis, lymphovascular invasion, capsular invasion, and extension to the surrounding muscles; staining positive for Mic-2 (CD-99 antigen, vimentin, synaptophysin, and Melan-A. Thoracocentesis, pleural fluid study, and pleural biopsy did not show metastasis. She responded well to vincristine, adriamycin, and cyclophosphamide followed by ifosfamide and etoposide (IE. This is the first report of adrenal peripheral PNET (pPNET from India. This report intends to highlight that pPNET should be suspected in a patient presenting with huge nonfunctional adrenal mass which may be confused with adrenocortical carcinoma.

  11. Primary Ewing Sarcoma/Primitive Neuroectodermal Tumor of the Stomach

    Science.gov (United States)

    Khuri, Safi; Gilshtein, Hayim; Sayidaa, Sa'd; Bishara, Bishara; Kluger, Yoram

    2016-01-01

    Ewing sarcoma/primitive neuroectodermal tumor (ES/PNET) is a tumor of small round cells arising in skeletal tissues. These tumors rarely arise in the stomach. We present a 31-year-old healthy female patient who was admitted to our surgical ward due to upper gastrointestinal hemorrhage. Upper endoscopy revealed a large ulcerated bleeding mass originating from the lesser curvature. Biopsy revealed tumor cell immunoreactivity positive for CD99, vimentin, and Ki67 (an index of proliferation). These findings were compatible with gastric ES/PNET. The fluorescence in situ hybridization analysis result for the EWSR1 gene rearrangement (11: 22 translocation) was positive. The patient refused neoadjuvant treatment and thus underwent an operation during which a mass at the lesser curvature of the stomach was found. The mass was adhering to the pancreatic tail and to the mesentery of the transverse and descending colon. Total gastrectomy, distal pancreatectomy, splenectomy, and left adrenalectomy were done. The patient refused adjuvant treatment. She is free of disease 3 years after surgery. PMID:27920700

  12. Ion size effect on colloidal forces within the primitive model

    Directory of Open Access Journals (Sweden)

    J.Wu

    2005-01-01

    Full Text Available The effect of ion size on the mean force between a pair of isolated charged particles in an electrolyte solution is investigated using Monte Carlo simulations within the framework of the primitive model where both colloidal particles and small ions are represented by charged hard spheres and the solvent is treated as a dielectric continuum. It is found that the short-ranged attraction between like-charged macroions diminishes as the diameter of the intermediating divalent counterions and coions increases and the maximum attractive force is approximately a linear function of the counterion diameter. This size effect contradicts the prediction of the Asakura-Oosawa theory suggesting that an increase in the excluded volume of small ions would lead to a stronger depletion between colloidal particles. Interestingly, the simulation results indicate that both the hard-sphere collision and the electrostatic contributions to the mean force are insensitive to the size disparity of colloidal particles with the same average diameter.

  13. Common leukocyte antigen staining of a primitive sarcoma.

    Science.gov (United States)

    McDonnell, J M; Beschorner, W E; Kuhajda, F P; deMent, S H

    1987-04-15

    A 4-year-old boy presented with symptoms of tracheal obstruction and was found to have a polypoid tracheal mass, which was studied by biopsy. Light microscopy showed a tumor composed of small cells with round to oval dark nuclei, clumped chromatin, one to two nucleoli, and small, variable amounts of indistinct pink cytoplasm. In other areas the tumor had a loose, spindle appearance, with some cells showing more elongated nuclei, and fibrillar pink cytoplasm consistent with strap cells. Cross striations were not found. Electron microscopy showed desmosomes and 7 to 10 nm cytoplasmic filaments forming dense bodies. The findings are most consistent with a primitive sarcoma, probably rhabdomyosarcoma. Immunoperoxidase with three monoclonal antibodies for common leukocyte antigen showed diffuse membraneous staining with fresh-frozen tissue. All other lymphocyte and monocyte marker studies were negative. We believe that this case of anticommon leukocyte antigen staining, a rhabdomyosarcoma, represents the first report of a false positive reaction with monoclonal antibody to common leukocyte antigen.

  14. Imitation learning of motor primitives and language bootstrapping in robots

    CERN Document Server

    Cederborg, Thomas

    2010-01-01

    Imitation learning in robots, also called programing by demonstration, has made important advances in recent years, allowing humans to teach context dependant motor skills/tasks to robots. We propose to extend the usual contexts investigated to also include acoustic linguistic expressions that might denote a given motor skill, and thus we target joint learning of the motor skills and their potential acoustic linguistic name. In addition to this, a modification of a class of existing algorithms within the imitation learning framework is made so that they can handle the unlabeled demonstration of several tasks/motor primitives without having to inform the imitator of what task is being demonstrated or what the number of tasks are, which is a necessity for language learning, i.e; if one wants to teach naturally an open number of new motor skills together with their acoustic names. Finally, a mechanism for detecting whether or not linguistic input is relevant to the task is also proposed, and our architecture als...

  15. Fermat quotients: Exponential sums, value set and primitive roots

    CERN Document Server

    Shparlinski, Igor E

    2011-01-01

    For a prime $p$ and an integer $u$ with $\\gcd(u,p)=1$, we define Fermat quotients by the conditions $$ q_p(u) \\equiv \\frac{u^{p-1} -1}{p} \\pmod p, \\qquad 0 \\le q_p(u) \\le p-1. $$ D. R. Heath-Brown has given a bound of exponential sums with $N$ consecutive Fermat quotients that is nontrivial for $N\\ge p^{1/2+\\epsilon}$ for any fixed $\\epsilon>0$. We use a recent idea of M. Z. Garaev together with a form of the large sieve inequality due to S. Baier and L. Zhao, to show that on average over $p$ one can obtain a nontrivial estimate for much shorter sums starting with $N\\ge p^{\\epsilon}$. We also obtain lower bounds on the image size of the first $N$ consecutive Fermat quotients and use it to prove that there is a positive integer $n\\le p^{3/4 + o(1)}$ such that $q_p(n)$ is a primitive root modulo $p$.

  16. Primitive Neuroectodermal Tumor (PNET of the kidney: a case report

    Directory of Open Access Journals (Sweden)

    Selli Cesare

    2004-01-01

    Full Text Available Abstract Background A case of Primitive Neuroectodermal Tumor (PNET of the kidney in a 27-year-old woman is presented. Few cases are reported in the literature with a variable, nonspecific presentation and an aggressive behaviour. In our case, a radical nephrectomy with lymphadenectomy was performed and there was no residual or recurrent tumour at 24-month follow-up. Methods The surgical specimens were formalin-fixed and paraffin embedded. The sections were stained with routinary H&E. Immunohistochemistry was performed. Results The immunohistochemical evaluation revealed a diffuse CD99 positivity in the cytoplasm of the neoplastic cells. Pankeratin, cytokeratin AE1/AE3, vimentin, desmin, S100, cromogranin were negative. The clinical presentation and the macroscopic aspect, together with the histological pattern, the cytological characteristic and the cellular immunophenotype addressed the diagnosis towards primary PNET of kidney. Conclusions Since sometimes it is difficult to discriminate between PNET and Ewing's tumour, we reviewed the difficulties in differential diagnosis. These tumors have a common precursor but the stage of differentiation in which it is blocked is probably different. This could also explain their different biological behaviour and prognosis.

  17. LIF supports primitive endoderm expansion during pre-implantation development

    DEFF Research Database (Denmark)

    Morgani, Sophie M; Brickman, Joshua M

    2015-01-01

    report that LIF has two distinct roles: it blocks early epiblast (Epi) differentiation, and it supports the expansion of primitive endoderm (PrE)-primed ESCs and PrE in vivo. We find that activation of JAK/STAT signalling downstream of LIF occurs initially throughout the pre-implantation embryo......, but later marks the PrE. Moreover, the addition of LIF to cultured embryos increases the GATA6(+) PrE population, whereas inhibition of JAK/STAT signalling reduces both NANOG(+) epiblast and GATA6(+) PrE. The reduction of the NANOG(+) Epi might be explained by its precocious differentiation to later Epi...... derivatives, whereas the increase in PrE is mediated both by an increase in proliferation and inhibition of PrE apoptosis that is normally triggered in embryos with an excess of GATA6(+) cells. Thus, it appears that the relative size of the PrE is determined by the number of LIF-producing cells in the embryo...

  18. Dynamical movement primitives: learning attractor models for motor behaviors.

    Science.gov (United States)

    Ijspeert, Auke Jan; Nakanishi, Jun; Hoffmann, Heiko; Pastor, Peter; Schaal, Stefan

    2013-02-01

    Nonlinear dynamical systems have been used in many disciplines to model complex behaviors, including biological motor control, robotics, perception, economics, traffic prediction, and neuroscience. While often the unexpected emergent behavior of nonlinear systems is the focus of investigations, it is of equal importance to create goal-directed behavior (e.g., stable locomotion from a system of coupled oscillators under perceptual guidance). Modeling goal-directed behavior with nonlinear systems is, however, rather difficult due to the parameter sensitivity of these systems, their complex phase transitions in response to subtle parameter changes, and the difficulty of analyzing and predicting their long-term behavior; intuition and time-consuming parameter tuning play a major role. This letter presents and reviews dynamical movement primitives, a line of research for modeling attractor behaviors of autonomous nonlinear dynamical systems with the help of statistical learning techniques. The essence of our approach is to start with a simple dynamical system, such as a set of linear differential equations, and transform those into a weakly nonlinear system with prescribed attractor dynamics by means of a learnable autonomous forcing term. Both point attractors and limit cycle attractors of almost arbitrary complexity can be generated. We explain the design principle of our approach and evaluate its properties in several example applications in motor control and robotics.

  19. Biophysical characterization of hematopoietic cells from normal and leukemic sources with distinct primitiveness

    Science.gov (United States)

    Tan, Youhua; Fung, Tsz-Kan; Wan, Haixia; Wang, Kaiqun; Leung, Anskar Y. H.; Sun, Dong

    2011-08-01

    This letter reported the biophysical characterization of immunophenotypically distinct hematopoietic cells from normal and leukemic sources, through manipulation with optical tweezers at single cell level. The results show that the percentage of cells that are stretchable and their deformability are significantly higher in the more primitive cell populations. This study provides the evidence that normal and leukemic hematopoietic cell populations with distinct primitiveness exhibit differential biophysical properties. These findings raise a hypothesis that the high deformability may be related to the unique functions and activities of primitive hematopoietic cells.

  20. The efficient global primitive equation climate model SPEEDO V2.0

    Directory of Open Access Journals (Sweden)

    C. A. Severijns

    2010-02-01

    Full Text Available The efficient primitive-equation coupled atmosphere-ocean model SPEEDO V2.0 is presented. The model includes an interactive sea-ice and land component. SPEEDO is a global earth system model of intermediate complexity. It has a horizontal resolution of T30 (triangular truncation at wave number 30 and 8 vertical layers in the atmosphere, and a horizontal resolution of 2 degrees and 20 levels in the ocean. The parameterisations in SPEEDO are developed in such a way that it is a fast model suitable for large ensembles or long runs (of O(104 years on a typical current workstation. The model has no flux correction. We compare the mean state and inter-annual variability of the model with observational fields of the atmosphere and ocean. In particular the atmospheric circulation, the mid-latitude patterns of variability and teleconnections from the tropics are well simulated. To show the capabilities of the model, we performed a long control run and an ensemble experiment with enhanced greenhouse gases. The long control run shows that the model is stable. CO2 doubling and future climate change scenario experiments show a climate sensitivity of 1.84 K W-1 m2, which is within the range of state-of-the-art climate models. The spatial response patterns are comparable to state-of-the-art, higher resolution models. However, for very high greenhouse gas concentrations the parameterisations are not valid. We conclude that the model is suitable for past, current and future climate simulations and for exploring wide parameter ranges and mechanisms of variability. However, as with any model, users should be careful when using the model beyond the range of physical realism of the parameterisations and model setup.

  1. Self-assembly and function of primitive cell membranes.

    Science.gov (United States)

    Pohorille, Andrew; Deamer, David

    2009-09-01

    We describe possible pathways for separating amphiphilic molecules from organic material on the early earth to form membrane-bound structures required for the start of cellular life. We review properties of the first membranes and their function as permeability barriers. Finally, we discuss the emergence of protein-mediated ion transport across membranes, which facilitated many other cellular functions.

  2. Delivery of micrometeoritic greenhouse gases and "smoke" particles during the post-lunar "late heavy bombardment" of the Earth

    Science.gov (United States)

    Maurette, M.; Brack, A.; Duprat, J.; Engrand, C.

    (1) Processed micrometeorites in Astrobiology. In previous studies, we considered the contribution of unmelted micrometeorites in astrobiology. We now argue that even processed micrometeorites that are destroyed upon atmospheric entry could have participated in the birth of life on Earth. Unweathered micrometeorites from our new "Concordia-collection" show high sulfur contents of about 5%. With the simple assumption that all sulfur from volatilized micrometeorites is initially oxidized during atmospheric entry, like organic carbon, our model predicts an enormous initial input rate of SO2 in the thermosphere (˜ 1016 g/yr) that lasted for, at least, 100 Myr after the Moon forming impact (this impact blew off the primitive atmosphere). This post-lunar SO2 input was probably quickly transformed into stratospheric sulfate aerosols that were finally deposited in the early oceans. A plausible reaction pathway to eliminate such an excess of sulfates requires the likely existence of abundant early hydrothermal sources, converting sulfates dissolved in water into huge deposits of iron sulfides and exhalations of H2S, as in contemporary sources. In the "sulfide world" promoted by Wächtershäuser, sulfides, FeS and H2S, can reduce CO2 to organic sulfides in the form of thiols, as demonstrated in laboratory simulation experiments. Thiols can lead to thioesters, which probably behaved as activating agents in prebiotic chemistry, according to de Duve; (2) Post-lunar greenhouse effects. It is likely that the greenhouse gases CO2 and H2O released from the Earth's interior counterbalanced the "faint" early Sun luminosity. But these gases were blown off by the Moon forming impact. However, during the first ˜ 100 Myr of the post-lunar period, we predict enormous input rates of three powerful micrometeoritic greenhouse gases (SO2, H2O, CO2). They should have produced a marked heating of the Earth's surface, which had to be counterbalanced by a strong cooling. Hunten and

  3. Melting the hydrous, subarc mantle: the origin of primitive andesites

    Science.gov (United States)

    Mitchell, Alexandra L.; Grove, Timothy L.

    2015-08-01

    This experimental study is the first comprehensive investigation of the melting behavior of an olivine + orthopyroxene ± spinel—bearing fertile mantle (FM) composition as a function of variable pressure and water content. The fertile composition was enriched with a metasomatic slab component of ≤0.5 % alkalis and investigated from 1135 to 1470 °C at 1.0-2.0 GPa. A depleted lherzolite with 0.4 % alkali addition was also studied from 1225 to 1240 °C at 1.2 GPa. Melts of both compositions were water-undersaturated: fertile lherzolite melts contained 0-6.4 wt% H2O, and depleted lherzolite melts contained ~2.5 wt% H2O. H2O contents of experimental glasses are measured using electron microprobe, secondary ion mass spectrometry, and synchrotron-source reflection Fourier transform infrared spectroscopy, a novel technique for analyzing H2O in petrologic experiments. Using this new dataset in conjunction with results from previous hydrous experimental studies, a thermobarometer and a hygrometer-thermometer are presented to determine the conditions under which primitive lavas were last in equilibration with the mantle. These predictive models are functions of H2O content and pressure, respectively. A predictive melting model is also presented that calculates melt compositions in equilibrium with an olivine + orthopyroxene ± spinel residual assemblage (harzburgite). This model quantitatively predicts the following influences of H2O on mantle lherzolite melting: (1) As melting pressure increases, melt compositions become more olivine-normative, (2) as melting extent increases, melt compositions become depleted in the normative plagioclase component, and (3) as melt H2O content increases, melts become more quartz-normative. Natural high-Mg# [molar Mg/(Mg + Fe2+)], high-MgO basaltic andesite and andesite lavas—or primitive andesites (PAs)—contain high SiO2 contents at mantle-equilibrated Mg#s. Their compositional characteristics cannot be readily explained by melting

  4. A plausible link between the asteroid 21 Lutetia and CH carbonaceous chondrites

    Science.gov (United States)

    Moyano-Cambero, Carles E.; Trigo-Rodríguez, Josep M.; Llorca, Jordi; Fornasier, Sonia; Barucci, Maria A.; Rimola, Albert

    2016-10-01

    A crucial topic in planetology research is establishing links between primitive meteorites and their parent asteroids. In this study, we investigate the feasibility of a connection between asteroids similar to 21 Lutetia, encountered by the Rosetta mission in July 2010, and the CH3 carbonaceous chondrite Pecora Escarpment 91467 (PCA 91467). Several spectra of this meteorite were acquired in the ultraviolet to near-infrared (0.3-2.2 μm) and in the midinfrared to thermal infrared (2.5-30.0 μm or 4000 to 333 cm-1), and they are compared here to spectra from the asteroid 21 Lutetia. There are several similarities in absorption bands and overall spectral behavior between this CH3 meteorite and 21 Lutetia. Considering also that the bulk density of Lutetia is similar to that of CH chondrites, we suggest that this asteroid could be similar, or related to, the parent body of these meteorites, if not the parent body itself. However, the apparent surface diversity of Lutetia pointed out in previous studies indicates that it could simultaneously be related to other types of chondrites. Future discovery of additional unweathered CH chondrites could provide deeper insight in the possible connection between this family of metal-rich carbonaceous chondrites and 21 Lutetia or other featureless, possibly hydrated high-albedo asteroids.

  5. A plausible link between the asteroid 21 Lutetia and CH carbonaceous chondrites

    CERN Document Server

    Moyano-Cambero, Carles E; Llorca, Jordi; Fornasier, Sonia; Barucci, Maria A; Rimola, Albert

    2016-01-01

    A crucial topic in planetology research is establishing links between primitive meteorites and their parent asteroids. In this study we investigate the feasibility of a connection between asteroids similar to 21 Lutetia, encountered by the Rosetta mission in July 2010, and the CH3 carbonaceous chondrite Pecora Escarpment 91467 (PCA 91467). Several spectra of this meteorite were acquired in the ultraviolet to near-infrared (0.3 to 2.2 {\\mu}m) and in the mid-infrared to thermal infrared (2.5 to 30.0 {\\mu}m or 4000 to ~333 cm^-1), and they are compared here to spectra from the asteroid 21 Lutetia. There are several similarities in absorption bands and overall spectral behavior between this CH3 meteorite and 21 Lutetia. Considering also that the bulk density of Lutetia is similar to that of CH chondrites, we suggest that this asteroid could be similar, or related to, the parent body of these meteorites, if not the parent body itself. However, the apparent surface diversity of Lutetia pointed out in previous studi...

  6. On the ineffectiveness of constant rotation in the primitive equations and their symmetry analysis

    CERN Document Server

    Cardoso-Bihlo, Elsa Dos Santos

    2015-01-01

    Modern weather and climate prediction models are based on a system of nonlinear partial differential equations called the primitive equations. Lie symmetries of the primitive equations are computed and the structure of its maximal Lie invariance algebra, which is infinite dimensional, is studied. The maximal Lie invariance algebra for the case of a nonzero constant Coriolis parameter is mapped to the case of vanishing Coriolis force. The same mapping allows one to transform the constantly rotating primitive equations to the equations in a resting reference frame. This mapping is used to obtain exact solutions for the rotating case from exact solutions from the nonrotating equations. Another important result of the paper is the computation of the complete point symmetry group of the primitive equations using the algebraic method.

  7. Graph C*-Algebras with a T1 Primitive Ideal Space

    DEFF Research Database (Denmark)

    Gabe, James 'Jamie'

    2013-01-01

    We give necessary and sufficient conditions which a graph should satisfy in order for its associated C∗-algebra to have a T1 primitive ideal space. We give a description of which one-point sets in such a primitive ideal space are open, and use this to prove that anypurely infinite graph C......∗-algebrapurely infinite graph C∗-algebra purely infinite graph C∗-algebra with a T1 (in particular Hausdorff) primitive ideal space, is a c0-direct sum of Kirchberg algebras. Moreover, we show that graph C∗-algebras with a T1 primitive ideal space canonically may be given the structure of a C(N ~ ) -algebra......, and that isomorphisms of their N ~ -filtered K-theory (without coefficients) lift to E(N ~ ) -equivalences, as defined by Dadarlat and Meyer...

  8. Normal Coordinates and Primitive Elements in the Hopf Algebra of Renormalization

    CERN Document Server

    Chryssomalakos, C; Rosenbaum, M; Vergara, J D

    2002-01-01

    We introduce normal coordinates on the infinite dimensional group $G$ introduced by Connes and Kreimer in their analysis of the Hopf algebra of rooted trees. We study the primitive elements of the algebra and show that they are generated by a simple application of the inverse Poincar\\'e lemma, given a closed left invariant 1-form on $G$. For the special case of the ladder primitives, we find a second description that relates them to the Hopf algebra of functionals on power series with the usual product. Either approach shows that the ladder primitives are given by the Schur polynomials. The relevance of the lower central series of the dual Lie algebra in the process of renormalization is also discussed, leading to a natural concept of $k$-primitiveness, which is shown to be equivalent to the one already in the literature.

  9. Kzp Regulates the Transcription of gata2 and pu.1 during Primitive Hematopoiesis in Zebrafish Embryos

    Institute of Scientific and Technical Information of China (English)

    Fang Liu; Shaohua Yao; Ting Zhang; Chun Xiao; Yanna Shang; Jin Liu; Xianming Mo

    2012-01-01

    Kaiso zinc finger-containing protein (Kzp),a maternally-derived transcription factor,controls dorsoventral patterning during zebrafish gastrulation.Here,we uncovered a new function for Kzp in zebrafish embryonic primitive hematopoiesis.The depletion of kzp led to defects in primitive hematopoiesis including the development of the erythroid and myeloid lineages.On the other hand,overexpression of kzp caused the ectopic expression of gatal,gata2,and pu.1.Chromosome immunoprecipitation assays revealed that Kzp protein directly binds to gatal,gata2,and pu.1 promoters.Interestingly,the ectopic expression of gata2 was able to rescue the erythroid,but not the myeloid lineage in kzp-depleted zebrafish embryos.gatal expression controlled by Kzp was dependent on gata2 during primitive erythropoiesis.Our results indicate that Kzp is a critical transcriptional factor for the expression of gata2 and pu.1 to modulate primitive hematopoiesis.

  10. Primitive neuroectodermal tumor presenting as a delayed sequela to cranial irradiation and intrathecal methotrexate

    Energy Technology Data Exchange (ETDEWEB)

    Barasch, E.S.; Altieri, D.; Decker, R.E.; Ahmed, S.; Lin, J.

    1988-11-01

    A patient developed a primitive neuroectodermal tumor (PNET) many years after therapeutic cerebral radiation and methotrexate treatment for leukemia. The differential radiologic and histologic diagnoses, as well as the possible co-oncogenic effects of radiation and methotrexate, are evaluated.

  11. Primitive Neuroectodermal Tumor with Glioblastoma Multiforme Components in an Adult: A Collision Tumor.

    Science.gov (United States)

    Forbes, Victoria; Vredenburgh, James

    2016-01-11

    We report a rare case of a central nervous system collision tumor in a 40-year-old woman. Histopathological examination of her large temporal tumor revealed two different components making up the tumor tissue. The predominant component of the tumor was found to be a primitive neuroectodermal tumor. The other component was glioblastoma multiforme. Both of these tumors carry a poor prognosis, and primitive neuroectodermal tumors are extremely uncommon in adults. Central nervous system neoplasms with the combined features of both primitive neuroectodermal tumor and malignant glioma are very rare and represent a diagnostic and treatment predicament. The patient underwent surgical resection, radiation therapy, and chemotherapy targeting both the primitive neuroectodermal tumor and glioblastoma. Our patient has been fortunate in not showing any sign of recurrence and will celebrate the third anniversary since her diagnosis this January.

  12. Supratentorial primitive neuroectodermal tumor in an adult: a case report and review of the literature

    Directory of Open Access Journals (Sweden)

    Lawandy Shokry

    2012-10-01

    Full Text Available Abstract Introduction Supratentorial primitive neuroectodermal tumors predominantly occur in children, and are rare in the adult population. Less than 100 cases of supratentorial primitive neuroectodermal tumor have been reported in adults internationally. Our case study reports this rare incident. Case presentation A 22-year-old Hispanic man presented with headaches, blurry vision, diplopia, intermittent vomiting, and grossly decreased vision. A magnetic resonance image showed a left posterior parietal heterogeneously enhancing mass measuring 4.2cm × 7.2cm × 7.0cm. After craniotomy for resection and decompression, the mass was histologically revealed to be a supratentorial primitive neuroectodermal tumor. Standardized immunohistochemical studies for this mass were carried out. Conclusion We have concluded that immunohistochemical and genetic workup should be included in the standardized pathological workup for primitive neuroectodermal tumors in order to provide more prognostic information. Based on our current literature review, we propose an immunohistochemical panel.

  13. Efficient conservative ADER schemes based on WENO reconstruction and space-time predictor in primitive variables

    CERN Document Server

    Zanotti, Olindo

    2015-01-01

    We present a new version of conservative ADER-WENO finite volume schemes, in which both the high order spatial reconstruction as well as the time evolution of the reconstruction polynomials in the local space-time predictor stage are performed in primitive variables, rather than in conserved ones. Since the underlying finite volume scheme is still written in terms of cell averages of the conserved quantities, our new approach performs the spatial WENO reconstruction twice: the first WENO reconstruction is carried out on the known cell averages of the conservative variables. The WENO polynomials are then used at the cell centers to compute point values of the conserved variables, which are converted into point values of the primitive variables. A second WENO reconstruction is performed on the point values of the primitive variables to obtain piecewise high order reconstruction polynomials of the primitive variables. The reconstruction polynomials are subsequently evolved in time with a novel space-time finite ...

  14. The genomes of two key bumblebee species with primitive eusocial organization

    DEFF Research Database (Denmark)

    Sadd, Ben M.; Barribeau, Seth M.; Bloch, Guy

    2015-01-01

    BACKGROUND: The shift from solitary to social behavior is one of the major evolutionary transitions. Primitively eusocial bumblebees are uniquely placed to illuminate the evolution of highly eusocial insect societies. Bumblebees are also invaluable natural and agricultural pollinators, and there ...

  15. Origin of Nanodiamonds in Primitive Chondrites: (1) Theory

    Science.gov (United States)

    Ozima, M.; Mochizuki, K.

    1993-07-01

    Microdiamonds in primitive chondrites are characterized by Xe-HL, which supposedly formed in a type II supernova. Several models have been proposed for the origin of the microdiamonds. These include chemical vapor deposition (CVD) [e.g., 1], interstellar shock [2], and UV-annealing of small graphite particles [3]. However, it is difficult for any of these models to explain the unique association of Xe-HL with the microdiamonds. We have suggested that a diamond formation process, proposed by Kaminsky [4], for the origin of a particular terrestrial diamond, carbonado, may apply to the microdiamonds in primitive meteorites [5,6]: Kaminsky speculated that carbonado was formed from natural coal that was enriched in uranium and hence subjected to irradiation by high-energy particles produced from the uranium and thorium. The paper in this volume by Mochizuki et al. [7] reports nanometer-sized diamondlike clusters in a uranium-rich natural coal, in accordance with Kaminsky's hypothesis. Mochizuki et al. also report the possibility of the production of nanodiamonds in graphite that was irradiated with a 50-KeV argon beam. These experimental studies strongly suggest that microdiamonds can be produced by irradiation of carbonaceous matters with energetic particles. On the basis of these experimental results, we propose a scenario for the origin of the microdiamonds in primitive chondrites. The scenario gives a reasonable explanation for the unique association of Xe-HL with the microdiamonds as well as for their formation in a supernova envelope. We assume that carbonaceous materials (amorphous carbon, graphite, and hydrocarbon grains) in the outer envelope of a supernova was irradiated by energetic particles (including Xe-HL) emitted during supernova explosion. The energetic particles then interacted with the carbonaceous matter: Most of the energy was dissipated through electronic interaction, and at the end of the journey the particles produced cascade displacement of

  16. Particle-Gas Dynamics and Primitive Meteorite Parent Bodies

    Science.gov (United States)

    Cuzzi, J. N.; Dobrovolskis, A. R.; Champney, J. M.; Hogan, R. M.

    1993-07-01

    A major obstacle to understanding the accretion of primitive meteorite parent bodies has been the lack of a credible theoretical framework for the environment in which the earliest accretion occurs. Chondrules and inclusions in primitive meteorites are in the millimeter-centimeter size range and the earliest aggregates of these objects must have been in the centimeter-meter size range. For these sizes, particle-gas dynamics are difficult to model: the particles are neither micron-sized and firmly anchored to the gas, nor kilometer-sized planetesimals already fully decoupled from the gas. Significant feedback and strong coupling between the gas and particle phases must be dealt with in this intermediate size range [1]. We have previously reported preliminary results concerning the stage of planetary formation during which the particulate material has grown into centimeter-to-meter sized primordial aggregates [2]. During this stage, particles are able to settle toward the midplane into a layer of mass density comparable to or much greater than that of the gas. We now report more mature results [3]. Our numerical models rely on the Reynolds averaged NavierStokes equations for the gas and particles, and are fully viscous, turbulent, and compressible. Our turbulence modeling uses a Prandtl local shear parametrization, validated by laboratory experiments. We have developed a new model for particle diffusivity (in turbulence) involving the particle Schmidt number, which is a function of particle size and density. We have modeled a cool, quiescent nebula at 1 AU (280K) and 10 AU (90K), and a possible FU Orionis or early high temperature stage (1000K) at 1 AU. Our main results include: (a) rapid accretion of planetesimals by gravitationally unstable fragmentation on an orbital timescale (the "Goldreich-Ward instability") is unlikely to occur until objects have already accreted by some other process to the mass of the largest known meteorite samples, if at all [4]; (b) from

  17. How the inclination of Earth's orbit affects incoming solar irradiance

    OpenAIRE

    Vieira, L.E.A.; Norton, A; T. Dudok de Wit; Kretzschmar, M; Schmidt, G. A.; Cheung, M.C.M.

    2012-01-01

    International audience; [1] The variability in solar irradiance, the main external energy source of the Earth's system, must be critically studied in order to place the effects of human-driven climate change into perspective and allow plausible predictions of the evolution of climate. Accurate measurements of total solar irradiance (TSI) variability by instruments onboard space platforms during the last three solar cycles indicate changes of approximately 0.1% over the sunspot cycle. Physics-...

  18. Retinoic acid signaling plays a restrictive role in zebrafish primitive myelopoiesis.

    Directory of Open Access Journals (Sweden)

    Dong Liang

    Full Text Available Retinoic acid (RA is known to regulate definitive myelopoiesis but its role in vertebrate primitive myelopoiesis remains unclear. Here we report that zebrafish primitive myelopoiesis is restricted by RA in a dose dependent manner mainly before 11 hpf (hours post fertilization when anterior hemangioblasts are initiated to form. RA treatment significantly reduces expressions of anterior hemangioblast markers scl, lmo2, gata2 and etsrp in the rostral end of ALPM (anterior lateral plate mesoderm of the embryos. The result indicates that RA restricts primitive myelopoiesis by suppressing formation of anterior hemangioblasts. Analyses of ALPM formation suggest that the defective primitive myelopoiesis resulting from RA treatment before late gastrulation may be secondary to global loss of cells for ALPM fate whereas the developmental defect resulting from RA treatment during 10-11 hpf should be due to ALPM patterning shift. Overexpressions of scl and lmo2 partially rescue the block of primitive myelopoiesis in the embryos treated with 250 nM RA during 10-11 hpf, suggesting RA acts upstream of scl to control primitive myelopoiesis. However, the RA treatment blocks the increased primitive myelopoiesis caused by overexpressing gata4/6 whereas the abolished primitive myelopoiesis in gata4/5/6 depleted embryos is well rescued by 4-diethylamino-benzaldehyde, a retinal dehydrogenase inhibitor, or partially rescued by knocking down aldh1a2, the major retinal dehydrogenase gene that is responsible for RA synthesis during early development. Consistently, overexpressing gata4/6 inhibits aldh1a2 expression whereas depleting gata4/5/6 increases aldh1a2 expression. The results reveal that RA signaling acts downstream of gata4/5/6 to control primitive myelopoiesis. But, 4-diethylamino-benzaldehyde fails to rescue the defective primitive myelopoiesis in either cloche embryos or lycat morphants. Taken together, our results demonstrate that RA signaling restricts

  19. Bipolar-pulses observed by the LRS/WFC-L onboard KAGUYA - Plausible evidence of lunar dust impact -

    Science.gov (United States)

    Kasahara, Yoshiya; Horie, Hiroki; Hashimoto, Kozo; Omura, Yoshiharu; Goto, Yoshitaka; Kumamoto, Atsushi; Ono, Takayuki; Tsunakawa, Hideo; Lrs/Wfc Team; Map/Lmag Team

    2010-05-01

    same) and thus most of bipolar-pulses which can be detected in MONO mode are cancelled in DIFF mode. This fact suggests that these bipolar pulses are not a kind of natural wave but these are caused by instantaneous potential changes of the KAGUYA spacecraft. Discussion: Similar type of bipolar-pulses has been observed by the monopole antenna measurements using Radio and Plasma Wave Science (RPWS) instruments on-board Cassini around Saturn [4]. They demonstrated that these bipolar pulses are caused by impacts of dusts floating around the Saturn. It is well-known that lunar dusts are widely dis-tributed in higher altitude range around the moon and it is plausible that these bipolar pulses are caused by the lunar dust impacts. In the presentation, we show the detailed charac-teristics of bipolar pulses detected by the WFC-L onboard KAGUYA. References: [1] Y. Kasahara et al., Earth, Planets and Space, 60(4), 341-351, 2008. [2] T. Ono et al., Earth, Planets and Space, 60(4), 321-332, 2008. [3] K. Hashimoto et al., The 4th SELENE (KAGUYA) Science Working Team Meeting, (this issue), 2010. [4] W.S. Kurth et al, Planetary and Space Science, 54(9-10), 988-998, 2006.

  20. Non-primitive rectangular cells for tight-binding electronic structure calculations

    OpenAIRE

    Boykin, Timothy; Kharche, Neerav; Klimeck, Gerhard

    2009-01-01

    Rectangular non-primitive unit cells are computationally convenient for use in nanodevice electronic structure and transport calculations. When these cells are used for Calculations of structures with periodicity, the resulting bands are zone-folded and must be unfolded in order to identify important gaps and masses. Before the zone-unfolding method can be applied, one must first determine the allowed wavevectors for the specific non-primitive cell. Because most computationally convenient non...

  1. Non-Primitive Rectangular Cells for Tight-Binding Electronic Structure Calculations

    OpenAIRE

    Boykin, Timothy B.

    2008-01-01

    Rectangular non-primitive unit cells are computationally convenient for use in nanodevice electronic structure and transport calculations. When these cells are used for calculations of structures with periodicity, the resulting bands are zone-folded and must be unfolded in order to identify important gaps and masses. Before the zone-unfolding method can be applied, one must first determine the allowed wavevectors for the specific non-primitive cell. Because most computationally convenient ...

  2. The primitive matrices of sandwich semigroups of generalized circulant Boolean matrices

    Institute of Scientific and Technical Information of China (English)

    LIU Jian-ping; CHEN Jin-song

    2013-01-01

    Let Gn(C) be the sandwich semigroup of generalized circulant Boolean matrices with the sandwich matrix C and GC (Jn) the set of all primitive matrices in Gn(C). In this paper, some necessary and suffi cient conditions for A in the semigroup Gn(C) to be primitive are given. We also show that GC (Jn) is a subsemigroup of Gn(C).

  3. Asymptotic behavior of critical primitive multi-type branching processes with immigration

    CERN Document Server

    Ispány, Márton

    2012-01-01

    Under natural assumptions a Feller type diffusion approximation is derived for critical multi-type branching processes with immigration when the offspring mean matrix is primitive (in other words, positively regular). Namely, it is proved that a sequence of appropriately scaled random step functions formed from a sequence of critical primitive multi-type branching processes with immigration converges weakly towards a squared Bessel process supported by a ray determined by the Perron vector of the offspring mean matrix.

  4. Diagnosis of Persistent Primitive Olfactory Artery Using CT Angiography: A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Yeo, Soo Hyun; Rho, Byung Hak; Kim, Eal Maan; Chang, Hyuk Won [Keimyung University College of Medicine, Daegu (Korea, Republic of); Sohn, Chul Ho [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    2009-09-15

    A persistent primitive olfactory artery is a rare vascular anomaly and is incidentally found without any associated symptom for the most part. However, it has clinical significance in view of its high association with the development of cerebral aneurysms occurring at the hairpin turn. We present a case of a persistent primitive olfactory artery incidentally diagnosed by a CT angiography as well as a literature review of related previous articles

  5. The Themis-Beagle families: Investigation of space-weathering processes on primitive surfaces

    Science.gov (United States)

    Fornasier, S.; Perna, D.; Lantz, C.; Barucci, M.

    2014-07-01

    In the past 20 years, enormous progress has been reached in the study of space-weathering (SW) effects on silicates and silicate asteroids. The so-called ordinary chondrite paradox, that is, lack of asteroids similar to the ordinary chondrites, which represent 80 % of meteorite falls, has been solved. These meteorites are now clearly related to S-type asteroids, as proved also by the direct measurements of the NEAR and HAYABUSA missions on the near-Earth asteroids Eros and Itokawa. Spectral differences between S-type asteroids and ordinary chondrites are caused by space-weathering effects, which produce a darkening in the albedo, a reddening of the spectra, and diminish the silicate absorption bands on the asteroids surfaces, exposed to cosmic radiation and solar wind. On the other hand, our understanding of space-weathering effects on primitive asteroids is still poor. Only few laboratory experiments have been devoted to the investigation of SW effects on dark carbonaceous chondrites and on complex organic materials. Irradiation of transparent organic materials produces firstly redder and darker materials that upon further processing turn flatter-bluish and darker (Kanuchova et al. 2012; Moroz et al. 2004). The Themis family is a natural laboratory to study primitive asteroids and space-weathering effects. The Themis family is located between 3.05 and 3.24 au, beyond the snow line, and it is composed of primitive asteroids. Themis is one of the most statistically reliable families in the asteroid belt. First discovered by Hirayama (1918), it has been identified as a family in all subsequent works, and it has 550 members as determined by Zappalà et al. (1995) and more than 4000 as determined by Nesvorny et al. (2010). The family formed probably about 2.3 Gyr ago as a result of a large-scale catastrophic disruption event of a parent asteroid 400 km in diameter colliding with a 190-km projectile (Marzari et al. 1995). Several Themis family members show absorption

  6. Primitive life outside the solar system: generalized chlorophylls

    Science.gov (United States)

    Coliolo, Fiorella; Schneider, Jean; Labeyrie, Antoine; Gastellu, Jean Philippe

    2001-08-01

    Suppose an Earth-like planet is discovered in the habitable zone of its parent star: it will then be possible to detect spectroscopic signatures of what is perhaps due to complex organic chemistry. A broad class of living organisms take their energy from the light of the parent star of their home planet. Whatever the physiological details are (including production or not of oxygen), this photosynthesis of organic material must result in the "pumping" of photons in the stellar spectrum. It must therefore lead to absorption bands in the star's spectrum reflected by the planet. We call these features "generalized chlorophylls", as they generalize the green color of terrestrial plants. The basic idea of our work is to estimate the existence or absence of this chlorophyll outside the solar system, leaving from the global spectrum of the Earth with wavelength between 400-2000 nm (Vis-Near IR).

  7. Sulfur Earth

    Science.gov (United States)

    de Jong, B. H.

    2007-12-01

    Variations in surface tension affect the buoyancy of objects floating in a liquid. Thus an object floating in water will sink deeper in the presence of dishwater fluid. This is a very minor but measurable effect. It causes for instance ducks to drown in aqueous solutions with added surfactant. The surface tension of liquid iron is very strongly affected by the presence of sulfur which acts as a surfactant in this system varying between 1.9 and 0.4 N/m at 10 mass percent Sulfur (Lee & Morita (2002), This last value is inferred to be the maximum value for Sulfur inferred to be present in the liquid outer core. Venting of Sulfur from the liquid core manifests itself on the Earth surface by the 105 to 106 ton of sulfur vented into the atmosphere annually (Wedepohl, 1984). Inspection of surface Sulfur emission indicates that venting is non-homogeneously distributed over the Earth's surface. The implication of such large variation in surface tension in the liquid outer core are that at locally low Sulfur concentration, the liquid outer core does not wet the predominantly MgSiO3 matrix with which it is in contact. However at a local high in Sulfur, the liquid outer core wets this matrix which in the fluid state has a surface tension of 0.4 N/m (Bansal & Doremus, 1986), couples with it, and causes it to sink. This differential and diapiric movement is transmitted through the essentially brittle mantle (1024 Pa.s, Lambeck & Johnson, 1998; the maximum value for ice being about 1030 Pa.s at 0 K, in all likely hood representing an upper bound of viscosity for all materials) and manifests itself on the surface by the roughly 20 km differentiation, about 0.1 % of the total mantle thickness, between topographical heights and lows with concomitant lateral movement in the crust and upper mantle resulting in thin skin tectonics. The brittle nature of the medium though which this movement is transmitted suggests that the extremes in topography of the D" layer are similar in range to

  8. In search of a primitive ontology for relativistic quantum field theory

    Energy Technology Data Exchange (ETDEWEB)

    Lam, Vincent [University of Lausanne, CH-1015 Lausanne (Switzerland)

    2014-07-01

    There is a recently much discussed approach to the ontology of quantum mechanics according to which the theory is ultimately about entities in 3-dimensional space and their temporal evolution. Such an ontology postulating from the start matter localized in usual physical space or spacetime, by contrast to an abstract high-dimensional space such as the configuration space of wave function realism, is called primitive ontology in the recent literature on the topic and finds its roots in Bell's notion of local beables. The main motivation for a primitive ontology lies in its explanatory power: the primitive ontology allows for a direct account of the behaviour and properties of familiar macroscopic objects. In this context, it is natural to look for a primitive ontology for relativistic quantum field theory (RQFT). The aim of this talk is to critically discuss this interpretative move within RQFT, in particular with respect to the foundational issue of the existence of unitarily inequivalent representations. Indeed the proposed primitive ontologies for RQFT rely either on a Fock space representation or a wave functional representation, which are strictly speaking only unambiguously available for free systems in flat spacetime. As a consequence, it is argued that these primitive ontologies constitute only effective ontologies and are hardly satisfying as a fundamental ontology for RQFT.

  9. Evaluating structural pattern recognition for handwritten math via primitive label graphs

    Science.gov (United States)

    Zanibbi, Richard; Mouchère, Harold; Viard-Gaudin, Christian

    2013-01-01

    Currently, structural pattern recognizer evaluations compare graphs of detected structure to target structures (i.e. ground truth) using recognition rates, recall and precision for object segmentation, classification and relationships. In document recognition, these target objects (e.g. symbols) are frequently comprised of multiple primitives (e.g. connected components, or strokes for online handwritten data), but current metrics do not characterize errors at the primitive level, from which object-level structure is obtained. Primitive label graphs are directed graphs defined over primitives and primitive pairs. We define new metrics obtained by Hamming distances over label graphs, which allow classification, segmentation and parsing errors to be characterized separately, or using a single measure. Recall and precision for detected objects may also be computed directly from label graphs. We illustrate the new metrics by comparing a new primitive-level evaluation to the symbol-level evaluation performed for the CROHME 2012 handwritten math recognition competition. A Python-based set of utilities for evaluating, visualizing and translating label graphs is publicly available.

  10. Semantics-based plausible reasoning to extend the knowledge coverage of medical knowledge bases for improved clinical decision support.

    Science.gov (United States)

    Mohammadhassanzadeh, Hossein; Van Woensel, William; Abidi, Samina Raza; Abidi, Syed Sibte Raza

    2017-01-01

    Capturing complete medical knowledge is challenging-often due to incomplete patient Electronic Health Records (EHR), but also because of valuable, tacit medical knowledge hidden away in physicians' experiences. To extend the coverage of incomplete medical knowledge-based systems beyond their deductive closure, and thus enhance their decision-support capabilities, we argue that innovative, multi-strategy reasoning approaches should be applied. In particular, plausible reasoning mechanisms apply patterns from human thought processes, such as generalization, similarity and interpolation, based on attributional, hierarchical, and relational knowledge. Plausible reasoning mechanisms include inductive reasoning, which generalizes the commonalities among the data to induce new rules, and analogical reasoning, which is guided by data similarities to infer new facts. By further leveraging rich, biomedical Semantic Web ontologies to represent medical knowledge, both known and tentative, we increase the accuracy and expressivity of plausible reasoning, and cope with issues such as data heterogeneity, inconsistency and interoperability. In this paper, we present a Semantic Web-based, multi-strategy reasoning approach, which integrates deductive and plausible reasoning and exploits Semantic Web technology to solve complex clinical decision support queries. We evaluated our system using a real-world medical dataset of patients with hepatitis, from which we randomly removed different percentages of data (5%, 10%, 15%, and 20%) to reflect scenarios with increasing amounts of incomplete medical knowledge. To increase the reliability of the results, we generated 5 independent datasets for each percentage of missing values, which resulted in 20 experimental datasets (in addition to the original dataset). The results show that plausibly inferred knowledge extends the coverage of the knowledge base by, on average, 2%, 7%, 12%, and 16% for datasets with, respectively, 5%, 10%, 15%, and

  11. Biologic plausibility, cellular effects, and molecular mechanisms of eicosapentaenoic acid (EPA) in atherosclerosis.

    Science.gov (United States)

    Borow, Kenneth M; Nelson, John R; Mason, R Preston

    2015-09-01

    Residual cardiovascular (CV) risk remains in dyslipidemic patients despite intensive statin therapy, underscoring the need for additional intervention. Eicosapentaenoic acid (EPA), an omega-3 polyunsaturated fatty acid, is incorporated into membrane phospholipids and atherosclerotic plaques and exerts beneficial effects on the pathophysiologic cascade from onset of plaque formation through rupture. Specific salutary actions have been reported relating to endothelial function, oxidative stress, foam cell formation, inflammation, plaque formation/progression, platelet aggregation, thrombus formation, and plaque rupture. EPA also improves atherogenic dyslipidemia characterized by reduction of triglycerides without raising low-density lipoprotein cholesterol. Other beneficial effects of EPA include vasodilation, resulting in blood pressure reductions, as well as improved membrane fluidity. EPA's effects are at least additive to those of statins when given as adjunctive therapy. In this review, we present data supporting the biologic plausibility of EPA as an anti-atherosclerotic agent with potential clinical benefit for prevention of CV events, as well as its cellular effects and molecular mechanisms of action. REDUCE-IT is an ongoing, randomized, controlled study evaluating whether the high-purity ethyl ester of EPA (icosapent ethyl) at 4 g/day combined with statin therapy is superior to statin therapy alone for reducing CV events in high-risk patients with mixed dyslipidemia. The results from this study are expected to clarify the role of EPA as adjunctive therapy to a statin for reduction of residual CV risk.

  12. Mindfulness and Cardiovascular Disease Risk: State of the Evidence, Plausible Mechanisms, and Theoretical Framework.

    Science.gov (United States)

    Loucks, Eric B; Schuman-Olivier, Zev; Britton, Willoughby B; Fresco, David M; Desbordes, Gaelle; Brewer, Judson A; Fulwiler, Carl

    2015-12-01

    The purpose of this review is to provide (1) a synopsis on relations of mindfulness with cardiovascular disease (CVD) and major CVD risk factors, and (2) an initial consensus-based overview of mechanisms and theoretical framework by which mindfulness might influence CVD. Initial evidence, often of limited methodological quality, suggests possible impacts of mindfulness on CVD risk factors including physical activity, smoking, diet, obesity, blood pressure, and diabetes regulation. Plausible mechanisms include (1) improved attention control (e.g., ability to hold attention on experiences related to CVD risk, such as smoking, diet, physical activity, and medication adherence), (2) emotion regulation (e.g., improved stress response, self-efficacy, and skills to manage craving for cigarettes, palatable foods, and sedentary activities), and (3) self-awareness (e.g., self-referential processing and awareness of physical sensations due to CVD risk factors). Understanding mechanisms and theoretical framework should improve etiologic knowledge, providing customized mindfulness intervention targets that could enable greater mindfulness intervention efficacy.

  13. A plausible (overlooked) super-luminous supernova in the SDSS Stripe 82 data

    CERN Document Server

    Kostrzewa-Rutkowska, Zuzanna; Wyrzykowski, Lukasz; Djorgovski, S George; Glikman, Eilat; Mahabal, Ashish A

    2013-01-01

    We present the discovery of a plausible super-luminous supernova (SLSN), found in the archival data of Sloan Digital Sky Survey (SDSS) Stripe 82, called PSN 000123+000504. The supernova peaked at M_g<-21.3 mag in the second half of September 2005, but was missed by the real-time supernova hunt. The observed part of the light curve (17 epochs) showed that the rise to the maximum took over 30 days, while the decline time lasted at least 70 days (observed frame), closely resembling other SLSNe of SN2007bi type. Spectrum of the host galaxy reveals a redshift of z=0.281 and the distance modulus of \\mu=40.77 mag. Combining this information with the SDSS photometry, we found the host galaxy to be an LMC-like irregular dwarf galaxy with the absolute magnitude of M_B=-18.2+/-0.2 mag and the oxygen abundance of 12+log[O/H]=8.3+/-0.2. Our SLSN follows the relation for the most energetic/super-luminous SNe exploding in low-metallicity environments, but we found no clear evidence for SLSNe to explode in low-luminosity ...

  14. Event-based plausibility immediately influences on-line language comprehension.

    Science.gov (United States)

    Matsuki, Kazunaga; Chow, Tracy; Hare, Mary; Elman, Jeffrey L; Scheepers, Christoph; McRae, Ken

    2011-07-01

    In some theories of sentence comprehension, linguistically relevant lexical knowledge, such as selectional restrictions, is privileged in terms of the time-course of its access and influence. We examined whether event knowledge computed by combining multiple concepts can rapidly influence language understanding even in the absence of selectional restriction violations. Specifically, we investigated whether instruments can combine with actions to influence comprehension of ensuing patients of (as in Rayner, Warren, Juhuasz, & Liversedge, 2004; Warren & McConnell, 2007). Instrument-verb-patient triplets were created in a norming study designed to tap directly into event knowledge. In self-paced reading (Experiment 1), participants were faster to read patient nouns, such as hair, when they were typical of the instrument-action pair (Donna used the shampoo to wash vs. the hose to wash). Experiment 2 showed that these results were not due to direct instrument-patient relations. Experiment 3 replicated Experiment 1 using eyetracking, with effects of event typicality observed in first fixation and gaze durations on the patient noun. This research demonstrates that conceptual event-based expectations are computed and used rapidly and dynamically during on-line language comprehension. We discuss relationships among plausibility and predictability, as well as their implications. We conclude that selectional restrictions may be best considered as event-based conceptual knowledge rather than lexical-grammatical knowledge.

  15. From ether to acid: A plausible degradation pathway of glycerol dialkyl glycerol tetraethers

    Science.gov (United States)

    Liu, Xiao-Lei; Birgel, Daniel; Elling, Felix J.; Sutton, Paul A.; Lipp, Julius S.; Zhu, Rong; Zhang, Chuanlun; Könneke, Martin; Peckmann, Jörn; Rowland, Steven J.; Summons, Roger E.; Hinrichs, Kai-Uwe

    2016-06-01

    Glycerol dialkyl glycerol tetraethers (GDGTs) are ubiquitous microbial lipids with extensive demonstrated and potential roles as paleoenvironmental proxies. Despite the great attention they receive, comparatively little is known regarding their diagenetic fate. Putative degradation products of GDGTs, identified as hydroxyl and carboxyl derivatives, were detected in lipid extracts of marine sediment, seep carbonate, hot spring sediment and cells of the marine thaumarchaeon Nitrosopumilus maritimus. The distribution of GDGT degradation products in environmental samples suggests that both biotic and abiotic processes act as sinks for GDGTs. More than a hundred newly recognized degradation products afford a view of the stepwise degradation of GDGT via (1) ether bond hydrolysis yielding hydroxyl isoprenoids, namely, GDGTol (glycerol dialkyl glycerol triether alcohol), GMGD (glycerol monobiphytanyl glycerol diether), GDD (glycerol dibiphytanol diether), GMM (glycerol monobiphytanol monoether) and bpdiol (biphytanic diol); (2) oxidation of isoprenoidal alcohols into corresponding carboxyl derivatives and (3) chain shortening to yield C39 and smaller isoprenoids. This plausible GDGT degradation pathway from glycerol ethers to isoprenoidal fatty acids provides the link to commonly detected head-to-head linked long chain isoprenoidal hydrocarbons in petroleum and sediment samples. The problematic C80 to C82 tetraacids that cause naphthenate deposits in some oil production facilities can be generated from H-shaped glycerol monoalkyl glycerol tetraethers (GMGTs) following the same process, as indicated by the distribution of related derivatives in hydrothermally influenced sediments.

  16. Plausible molecular and crystal structures of chitosan/HI type II salt.

    Science.gov (United States)

    Lertworasirikul, Amornrat; Noguchi, Keiichi; Ogawa, Kozo; Okuyama, Kenji

    2004-03-15

    Chitosan/HI type II salt prepared from crab tendon was investigated by X-ray fiber diffraction. Two polymer chains and 16 iodide ions (I(-)) crystallized in a tetragonal unit cell with lattice parameters of a = b = 10.68(3), c (fiber axis) = 40.77(13) A, and a space group P4(1). Chitosan forms a fourfold helix with a 40.77 A fiber period having a disaccharide as the helical asymmetric unit. One of the O-3... O-5 intramolecular hydrogen bonds at the glycosidic linkage is weakened by interacting with iodide ions, which seems to cause the polymer to take the 4/1-helical symmetry rather than the extended 2/1-helix. The plausible orientations of two O-6 atoms in the helical asymmetric unit were found to be gt and gg. Two chains are running through at the corner and the center of the unit cell along the c-axis. They are linked by hydrogen bonds between N-21 and O-61 atoms. Two out of four independent iodide ions are packed between the corner chains while the other two are packed between the corner and center chains when viewing through the ab-plane. The crystal structure of the salt is stabilized by hydrogen bonds between these iodide ions and N-21, N-22, O-32, O-61, O-62 of the polymer chains.

  17. Solvent effects on the photochemistry of 4-aminoimidazole-5-carbonitrile, a prebiotically plausible precursor of purines.

    Science.gov (United States)

    Szabla, Rafał; Sponer, Judit E; Sponer, Jiří; Sobolewski, Andrzej L; Góra, Robert W

    2014-09-01

    4-Aminoimidazole-5-carbonitrile (AICN) was suggested as a prebiotically plausible precursor of purine nucleobases and nucleotides. Although it can be formed in a sequence of photoreactions, AICN is immune to further irradiation with UV-light. We present state-of-the-art multi-reference quantum-chemical calculations of potential energy surface cuts and conical intersection optimizations to explain the molecular mechanisms underlying the photostability of this compound. We have identified the N-H bond stretching and ring-puckering mechanisms that should be responsible for the photochemistry of AICN in the gas phase. We have further considered the photochemistry of AICN-water clusters, while including up to six explicit water molecules. The calculations reveal charge transfer to solvent followed by formation of an H3O(+) cation, both of which occur on the (1)πσ* hypersurface. Interestingly, a second proton transfer to an adjacent water molecule leads to a (1)πσ*/S0 conical intersection. We suggest that this electron-driven proton relay might be characteristic of low-lying (1)πσ* states in chromophore-water clusters. Owing to its nature, this mechanism might also be responsible for the photostability of analogous organic molecules in bulk water.

  18. A biologically plausible learning rule for the Infomax on recurrent neural networks.

    Science.gov (United States)

    Hayakawa, Takashi; Kaneko, Takeshi; Aoyagi, Toshio

    2014-01-01

    A fundamental issue in neuroscience is to understand how neuronal circuits in the cerebral cortex play their functional roles through their characteristic firing activity. Several characteristics of spontaneous and sensory-evoked cortical activity have been reproduced by Infomax learning of neural networks in computational studies. There are, however, still few models of the underlying learning mechanisms that allow cortical circuits to maximize information and produce the characteristics of spontaneous and sensory-evoked cortical activity. In the present article, we derive a biologically plausible learning rule for the maximization of information retained through time in dynamics of simple recurrent neural networks. Applying the derived learning rule in a numerical simulation, we reproduce the characteristics of spontaneous and sensory-evoked cortical activity: cell-assembly-like repeats of precise firing sequences, neuronal avalanches, spontaneous replays of learned firing sequences and orientation selectivity observed in the primary visual cortex. We further discuss the similarity between the derived learning rule and the spike timing-dependent plasticity of cortical neurons.

  19. Plausible ergogenic effects of vitamin D on athletic performance and recovery.

    Science.gov (United States)

    Dahlquist, Dylan T; Dieter, Brad P; Koehle, Michael S

    2015-01-01

    The purpose of this review is to examine vitamin D in the context of sport nutrition and its potential role in optimizing athletic performance. Vitamin D receptors (VDR) and vitamin D response elements (VDREs) are located in almost every tissue within the human body including skeletal muscle. The hormonally-active form of vitamin D, 1,25-dihydroxyvitamin D, has been shown to play critical roles in the human body and regulates over 900 gene variants. Based on the literature presented, it is plausible that vitamin D levels above the normal reference range (up to 100 nmol/L) might increase skeletal muscle function, decrease recovery time from training, increase both force and power production, and increase testosterone production, each of which could potentiate athletic performance. Therefore, maintaining higher levels of vitamin D could prove beneficial for athletic performance. Despite this situation, large portions of athletic populations are vitamin D deficient. Currently, the research is inconclusive with regards to the optimal intake of vitamin D, the specific forms of vitamin D one should ingest, and the distinct nutrient-nutrient interactions of vitamin D with vitamin K that affect arterial calcification and hypervitaminosis. Furthermore, it is possible that dosages exceeding the recommendations for vitamin D (i.e. dosages up to 4000-5000 IU/day), in combination with 50 to 1000 mcg/day of vitamin K1 and K2 could aid athletic performance. This review will investigate these topics, and specifically their relevance to athletic performance.

  20. A simple biophysically plausible model for long time constants in single neurons.

    Science.gov (United States)

    Tiganj, Zoran; Hasselmo, Michael E; Howard, Marc W

    2015-01-01

    Recent work in computational neuroscience and cognitive psychology suggests that a set of cells that decay exponentially could be used to support memory for the time at which events took place. Analytically and through simulations on a biophysical model of an individual neuron, we demonstrate that exponentially decaying firing with a range of time constants up to minutes could be implemented using a simple combination of well-known neural mechanisms. In particular, we consider firing supported by calcium-controlled cation current. When the amount of calcium leaving the cell during an interspike interval is larger than the calcium influx during a spike, the overall decay in calcium concentration can be exponential, resulting in exponential decay of the firing rate. The time constant of the decay can be several orders of magnitude larger than the time constant of calcium clearance, and it could be controlled externally via a variety of biologically plausible ways. The ability to flexibly and rapidly control time constants could enable working memory of temporal history to be generalized to other variables in computing spatial and ordinal representations.

  1. A plausible mechanism of biosorption in dual symbioses by vesicular-arbuscular mycorrhizal in plants.

    Science.gov (United States)

    Azmat, Rafia; Hamid, Neelofer

    2015-03-01

    Dual symbioses of vesicular-arbuscular mycorrhizal (VAM) fungi with growth of Momordica charantia were elucidated in terms of plausible mechanism of biosorption in this article. The experiment was conducted in green house and mixed inoculum of the VAM fungi was used in the three replicates. Results demonstrated that the starch contents were the main source of C for the VAM to builds their hyphae. The increased plant height and leaves surface area were explained in relation with an increase in the photosynthetic rates to produce rapid sugar contents for the survival of plants. A decreased in protein, and amino acid contents and increased proline and protease activity in VAM plants suggested that these contents were the main bio-indicators of the plants under biotic stress. The decline in protein may be due to the degradation of these contents, which later on converted into dextrose where it can easily be absorbed by for the period of symbioses. A mechanism of C chemisorption in relation with physiology and morphology of plant was discussed.

  2. Vitamin D in primary biliary cirrhosis, a plausible marker of advanced disease.

    Science.gov (United States)

    Agmon-Levin, Nancy; Kopilov, Ron; Selmi, Carlo; Nussinovitch, Udi; Sánchez-Castañón, María; López-Hoyos, Marcos; Amital, Howie; Kivity, Shaye; Gershwin, Eric M; Shoenfeld, Yehuda

    2015-02-01

    Vitamin D immune-modulating effects were extensively studied, and low levels have been linked with autoimmune diseases. The associations of vitamin D with autoimmune diseases of the liver, and particularly primary biliary cirrhosis (PBC), are yet to be defined. Hence, in this study, serum levels of vitamin D were determined in 79 patients with PBC and 70 age- and sex-matched controls by the LIAISON chemiluminescent immunoassays (DiaSorin-Italy). Clinical and serological parameters of patients were analyzed with respect to vitamin D status. Mean levels of vitamin D were significantly lower among patients with PBC compared with controls (16.8 ± 9 vs. 22.1 ± 9 ng/ml; p = 0.029), and vitamin D deficiency (≤10 ng/ml) was documented in 33% of patients with PBC versus 7% of controls (p plausible roles of vitamin D as a prognostic marker of PBC severity, and as a potential player in this disease pathogenesis. While further studies are awaited, monitoring vitamin D in patients with PBC and use of supplements may be advisable.

  3. Is the de Broglie-Bohm interpretation of quantum mechanics really plausible?

    Science.gov (United States)

    Jung, Kurt

    2013-06-01

    Bohmian mechanics also known as de Broglie-Bohm theory is the most popular alternative approach to quantum mechanics. Whereas the standard interpretation of quantum mechanics is based on the complementarity principle Bohmian mechanics assumes that both particle and wave are concrete physical objects. In 1993 Peter Holland has written an ardent account on the plausibility of the de Broglie-Bohm theory. He proved that it fully reproduces quantum mechanics if the initial particle distribution is consistent with a solution of the Schrödinger equation. Which may be the reasons that Bohmian mechanics has not yet found global acceptance? In this article it will be shown that predicted properties of atoms and molecules are in conflict with experimental findings. Moreover it will be demonstrated that repeatedly published ensembles of trajectories illustrating double slit diffraction processes do not agree with quantum mechanics. The credibility of a theory is undermined when recognizably wrong data presented frequently over years are finally not declared obsolete.

  4. Plausible futures of a social-ecological system: Yahara watershed, Wisconsin, USA

    Directory of Open Access Journals (Sweden)

    Stephen R. Carpenter

    2015-06-01

    Full Text Available Agricultural watersheds are affected by changes in climate, land use, agricultural practices, and human demand for energy, food, and water resources. In this context, we analyzed the agricultural, urbanizing Yahara watershed (size: 1345 km², population: 372,000 to assess its responses to multiple changing drivers. We measured recent trends in land use/cover and water quality of the watershed, spatial patterns of 10 ecosystem services, and spatial patterns and nestedness of governance. We developed scenarios for the future of the Yahara watershed by integrating trends and events from the global scenarios literature, perspectives of stakeholders, and models of biophysical drivers and ecosystem services. Four qualitative scenarios were created to explore plausible trajectories to the year 2070 in the watershed's social-ecological system under different regimes: no action on environmental trends, accelerated technological development, strong intervention by government, and shifting values toward sustainability. Quantitative time-series for 2010-2070 were developed for weather and land use/cover during each scenario as inputs to model changes in ecosystem services. Ultimately, our goal is to understand how changes in the social-ecological system of the Yahara watershed, including management of land and water resources, can build or impair resilience to shifting drivers, including climate.

  5. Plausible impact of global climate change on water resources in the Tarim River Basin

    Institute of Scientific and Technical Information of China (English)

    CHEN; Yaning; XU; Zongxue

    2005-01-01

    Combining the temperature and precipitation data from 77 climatological stations and the climatic and hydrological change data from three headstreams of the Tarim River: Hotan, Yarkant, and Aksu in the study area, the plausible association between climate change and the variability of water resources in the Tarim River Basin in recent years was investigated, the long-term trend of the hydrological time series including temperature, precipitation, and streamflow was detected, and the possible association between the El Ni(n)o/Southern Oscillation (ENSO) and these three kinds of time series was tested. The results obtained in this study show that during the past years, the temperature experienced a significant monotonic increase at the speed of 5%, nearly 1℃ rise; the precipitation showed a significant decrease in the 1970s, and a significant increase in the1980s and 1990s, the average annual precipitation was increased with the magnitude of 6.8 mm per decade. A step change occurred in both temperature and precipitation time series around 1986, which may be influenced by the global climate change. Climate change resulted in the increase of the streamflow at the headwater of the Tarim River, but the anthropogenic activities such as over-depletion of the surface water resulted in the decrease of the streamflow at the lower reaches of the Tarim River. The study result also showed that there is no significant association between the ENSO and the temperature, precipitation and streamflow.

  6. 论原始宗教与原始文化艺术的关系%Reading Primitive Culture from Original Religion

    Institute of Scientific and Technical Information of China (English)

    李洋

    2011-01-01

    原始宗教是维系原始文化的精神纽带,是原始文化的思想内容,原始文化是原始宗教的表现形式。原始文化艺术渗透在原始宗教中。%Primitive religion was spirit ligament to keep up primitive culture and the thought contents of primitive culture.Primitive culture art was the form of expression of primitive religion.Primitive culture art was permeated in the primitive religion.

  7. Cultural group selection is plausible, but the predictions of its hypotheses should be tested with real-world data.

    Science.gov (United States)

    Turchin, Peter; Currie, Thomas E

    2016-01-01

    The evidence compiled in the target article demonstrates that the assumptions of cultural group selection (CGS) theory are often met, and it is therefore a useful framework for generating plausible hypotheses. However, more can be said about how we can test the predictions of CGS hypotheses against competing explanations using historical, archaeological, and anthropological data.

  8. Ectopic Runx1 expression rescues Tal-1-deficiency in the generation of primitive and definitive hematopoiesis.

    Directory of Open Access Journals (Sweden)

    Julia Tornack

    Full Text Available The transcription factors SCL/Tal-1 and AML1/Runx1 control the generation of pluripotent hematopoietic stem cells (pHSC and, thereby, primitive and definitive hematopoiesis, during embryonic development of the mouse from mesoderm. Thus, Runx1-deficient mice generate primitive, but not definitive hematopoiesis, while Tal-1-deficient mice are completely defective. Primitive as well as definitive hematopoiesis can be developed "in vitro" from embryonic stem cells (ESC. We show that wild type, as well as Tal-1(-/- and Runx1(-/- ESCs, induced to differentiation, all expand within 5 days to comparable numbers of Flk1(+ mesodermal cells. While wild type ESCs further differentiate to primitive and definitive erythrocytes, to c-fms(+Gr1(+Mac1(+ myeloid cells, and to B220(+CD19(+ B- and CD4(+/CD8(+ T-lymphoid cells, Runx1(-/- ESCs, as expected, only develop primitive erythrocytes, and Tal-1(-/- ESCs do not generate any hematopoietic cells. Retroviral transduction with Runx1 of Runx1(-/- ESCs, differentiated for 4 days to mesoderm, rescues definitive erythropoiesis, myelopoiesis and lymphopoiesis, though only with 1-10% of the efficiencies of wild type ESC hematopoiesis. Surprisingly, Tal-1(-/- ESCs can also be rescued at comparably low efficiencies to primitive and definitive erythropoiesis, and to myelopoiesis and lymphopoiesis by retroviral transduction with Runx1. These results suggest that Tal-1 expression is needed to express Runx1 in mesoderm, and that ectopic expression of Runx1 in mesoderm is sufficient to induce primitive as well as definitive hematopoiesis in the absence of Tal-1. Retroviral transduction of "in vitro" differentiating Tal-1(-/- and Runx1(-/- ESCs should be a useful experimental tool to probe selected genes for activities in the generation of hematopoietic progenitors "in vitro", and to assess the potential transforming activities in hematopoiesis of mutant forms of Tal-1 and Runx1 from acute myeloid leukemia and related tumors.

  9. Flux-based transport enhancement as a plausible unifying mechanism for auxin transport in meristem development.

    Directory of Open Access Journals (Sweden)

    Szymon Stoma

    2008-10-01

    Full Text Available Plants continuously generate new organs through the activity of populations of stem cells called meristems. The shoot apical meristem initiates leaves, flowers, and lateral meristems in highly ordered, spiralled, or whorled patterns via a process called phyllotaxis. It is commonly accepted that the active transport of the plant hormone auxin plays a major role in this process. Current hypotheses propose that cellular hormone transporters of the PIN family would create local auxin maxima at precise positions, which in turn would lead to organ initiation. To explain how auxin transporters could create hormone fluxes to distinct regions within the plant, different concepts have been proposed. A major hypothesis, canalization, proposes that the auxin transporters act by amplifying and stabilizing existing fluxes, which could be initiated, for example, by local diffusion. This convincingly explains the organised auxin fluxes during vein formation, but for the shoot apical meristem a second hypothesis was proposed, where the hormone would be systematically transported towards the areas with the highest concentrations. This implies the coexistence of two radically different mechanisms for PIN allocation in the membrane, one based on flux sensing and the other on local concentration sensing. Because these patterning processes require the interaction of hundreds of cells, it is impossible to estimate on a purely intuitive basis if a particular scenario is plausible or not. Therefore, computational modelling provides a powerful means to test this type of complex hypothesis. Here, using a dedicated computer simulation tool, we show that a flux-based polarization hypothesis is able to explain auxin transport at the shoot meristem as well, thus providing a unifying concept for the control of auxin distribution in the plant. Further experiments are now required to distinguish between flux-based polarization and other hypotheses.

  10. Identifying and reducing potentially wrong immunoassay results even when plausible and "not-unreasonable".

    Science.gov (United States)

    Ismail, Adel A A

    2014-01-01

    The primary role of the clinical laboratory is to report accurate results for diagnosis of disease and management of illnesses. This goal has, to a large extent been achieved for routine biochemical tests, but not for immunoassays which remained susceptible to interference from endogenous immunoglobulin antibodies, causing false, and clinically misleading results. Clinicians regard all abnormal results including false ones as "pathological" necessitating further investigations, or concluding iniquitous diagnosis. Even more seriously, "false-negative" results may wrongly exclude pathology, thus denying patients' necessary treatment. Analytical error rate in immunoassays is relatively high, ranging from 0.4% to 4.0%. Because analytical interference from endogenous antibodies is confined to individuals' sera, it can be inconspicuous, pernicious, sporadic, and insidious because it cannot be detected by internal or external quality assessment procedures. An approach based on Bayesian reasoning can enhance the robustness of clinical validation in highlighting potentially erroneous immunoassay results. When this rational clinical/statistical approach is followed by analytical affirmative follow-up tests, it can help identifying inaccurate and clinically misleading immunoassay data even when they appear plausible and "not-unreasonable." This chapter is largely based on peer reviewed articles associated with and related to this approach. The first section underlines (without mathematical equations) the dominance and misuse of conventional statistics and the underuse of Bayesian paradigm and shows that laboratorians are intuitively (albeit unwittingly) practicing Bayesians. Secondly, because interference from endogenous antibodies is method's dependent (with numerous formats and different reagents), it is almost impossible to accurately assess its incidence in all differently formulated immunoassays and for each analytes/biomarkers. However, reiterating the basic concepts

  11. A plausible (overlooked) super-luminous supernova in the Sloan digital sky survey stripe 82 data

    Energy Technology Data Exchange (ETDEWEB)

    Kostrzewa-Rutkowska, Zuzanna; Kozłowski, Szymon; Wyrzykowski, Łukasz [Warsaw University Observatory, Al. Ujazdowskie 4, 00-478 Warszawa (Poland); Djorgovski, S. George; Mahabal, Ashish A. [California Institute of Technology, 1200 E California Blvd., Pasadena, CA 91125 (United States); Glikman, Eilat [Department of Physics and Yale Center for Astronomy and Astrophysics, Yale University, P.O. Box 208121, New Haven, CT 06520-8121 (United States); Koposov, Sergey, E-mail: zkostrzewa@astrouw.edu.pl, E-mail: simkoz@astrouw.edu.pl, E-mail: wyrzykow@astrouw.edu.pl [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA (United Kingdom)

    2013-12-01

    We present the discovery of a plausible super-luminous supernova (SLSN), found in the archival data of Sloan Digital Sky Survey (SDSS) Stripe 82, called PSN 000123+000504. The supernova (SN) peaked at m {sub g} < 19.4 mag in the second half of 2005 September, but was missed by the real-time SN hunt. The observed part of the light curve (17 epochs) showed that the rise to the maximum took over 30 days, while the decline time lasted at least 70 days (observed frame), closely resembling other SLSNe of SN 2007bi type. The spectrum of the host galaxy reveals a redshift of z = 0.281 and the distance modulus of μ = 40.77 mag. Combining this information with the SDSS photometry, we found the host galaxy to be an LMC-like irregular dwarf galaxy with an absolute magnitude of M{sub B} = –18.2 ± 0.2 mag and an oxygen abundance of 12+log [O/H]=8.3±0.2; hence, the SN peaked at M {sub g} < –21.3 mag. Our SLSN follows the relation for the most energetic/super-luminous SNe exploding in low-metallicity environments, but we found no clear evidence for SLSNe to explode in low-luminosity (dwarf) galaxies only. The available information on the PSN 000123+000504 light curve suggests the magnetar-powered model as a likely scenario of this event. This SLSN is a new addition to a quickly growing family of super-luminous SNe.

  12. Bio-physically plausible visualization of highly scattering fluorescent neocortical models for in silico experimentation

    KAUST Repository

    Abdellah, Marwan

    2017-02-15

    Background We present a visualization pipeline capable of accurate rendering of highly scattering fluorescent neocortical neuronal models. The pipeline is mainly developed to serve the computational neurobiology community. It allows the scientists to visualize the results of their virtual experiments that are performed in computer simulations, or in silico. The impact of the presented pipeline opens novel avenues for assisting the neuroscientists to build biologically accurate models of the brain. These models result from computer simulations of physical experiments that use fluorescence imaging to understand the structural and functional aspects of the brain. Due to the limited capabilities of the current visualization workflows to handle fluorescent volumetric datasets, we propose a physically-based optical model that can accurately simulate light interaction with fluorescent-tagged scattering media based on the basic principles of geometric optics and Monte Carlo path tracing. We also develop an automated and efficient framework for generating dense fluorescent tissue blocks from a neocortical column model that is composed of approximately 31000 neurons. Results Our pipeline is used to visualize a virtual fluorescent tissue block of 50 μm3 that is reconstructed from the somatosensory cortex of juvenile rat. The fluorescence optical model is qualitatively analyzed and validated against experimental emission spectra of different fluorescent dyes from the Alexa Fluor family. Conclusion We discussed a scientific visualization pipeline for creating images of synthetic neocortical neuronal models that are tagged virtually with fluorescent labels on a physically-plausible basis. The pipeline is applied to analyze and validate simulation data generated from neuroscientific in silico experiments.

  13. Untemplated nonenzymatic polymerization of 3',5'cGMP: a plausible route to 3',5'-linked oligonucleotides in primordia.

    Science.gov (United States)

    Šponer, Judit E; Šponer, Jiří; Giorgi, Alessandra; Di Mauro, Ernesto; Pino, Samanta; Costanzo, Giovanna

    2015-02-19

    The high-energy 3',5' phosphodiester linkages conserved in 3',5' cyclic GMPs offer a genuine solution for monomer activation required by the transphosphorylation reactions that could lead to the emergence of the first simple oligonucleotide sequences on the early Earth. In this work we provide an in-depth characterization of the effect of the reaction conditions on the yield of the polymerization reaction of 3',5' cyclic GMPs both in aqueous environment as well as under dehydrating conditions. We show that the threshold temperature of the polymerization is about 30 °C lower under dehydrating conditions than in solution. In addition, we present a plausible exergonic reaction pathway for the polymerization reaction, which involves transient formation of anionic centers at the O3' positions of the participating riboses. We suggest that excess Na(+) cations inhibit the polymerization reaction because they block the anionic mechanism via neutralizing the negatively charged O3'. Our experimental findings are compatible with a prebiotic scenario, where gradual desiccation of the environment could induce polymerization of 3',5' cyclic GMPs synthesized in liquid.

  14. Origin of Nanodiamonds in Primitive Chondrites: (2) Experiment

    Science.gov (United States)

    Mochizuki, K.; Ozima, M.; Tuchiyama, A.; Kitamura, M.; Shimobayashi, N.

    1993-07-01

    Ozima and Mochizuki [1] suggested that microdiamonds in primitive meteorites were formed by irradiation of carbonaceous matters such as graphite, amorphous carbon, or hydrocarbons with energetic particles emitted from supernova. To test this hypothesis, we carried out the following experiments. 1. We investigated a uranium-rich coal from Cluff Lake, Canada. Electron microprobe analysis of this sample showed that there are numerous uranium oxide grains of about 10-20 micrometers almost uniformly distributed in hydrocarbon matrix. A small amount of PbS was also identified by the EPMA analysis. If the U,Th-induced radiation were to produce diamonds, they must be found in radiation-damaged regions around the uranium oxide grains. Hence, we very carefully searched for microdiamonds in the radiation-damaged regions by TEM (transmission electron microscope). We observed many crystalline particles of about 20 nm, of which concentration in the radiation damaged region is about 500 ppm. Electron diffraction analysis with a TEM on the crystalline particles gave a powder ring pattern. Because of the limited resolution of the TEM, the electron diffraction was taken over an area (about 0.5 micrometers x 0.5 micrometers) that contained several grains. In Table 1, we show the spacing characteristics deduced from the diffraction analysis, where the observed d-spacings (denoted as D) are normalized to the table values corresponding to diamond, graphite, and PbS (denoted as d) respectively. If diamond is chosen for the normalization, the D/d ratios become almost constant for major diamond spacings, including the three most intense ones (shown by bold letters). One intense spacing at D = 1.887 angstroms, however, cannot be attributed to diamond, but may be due to PbS. We conclude that the observed electron diffraction pattern is primarily due to diamond, but other components such as PbS may also be present. Hence, the experiment seems to confirm Kaminsky's hypothesis [2] that high

  15. Primitive shoshonites from Fiji: Geochemistry and source components

    Science.gov (United States)

    Leslie, Roman A. J.; Danyushevsky, Leonid V.; Crawford, Anthony J.; Verbeeten, Alicia C.

    2009-07-01

    The eruption of shoshonitic magmas in Fiji during the Late Miocene-Pliocene (5.5-3 Ma) from 11 main volcanic centers along three broad ENE and NNW trending lineaments coincides with well-developed spreading in the North Fiji and Lau back-arc basins and maximum rotation of the Fiji Platform. The most mafic shoshonitic lavas (absarokites) range from 8.4 to 15.2 wt % MgO and are variably clinopyroxene + olivine-phyric. Fijian shoshonitic suites display a range of enrichment in large ion lithophile elements, Th, U, and P relative to rare earth elements and high field strength elements (HFSE), reflecting variable contributions by the subarc mantle source and subduction-related components. The subarc mantle source component controls HFSE, heavy rare earth elements, to a lesser degree light rare earth elements (LREE), and most importantly the sensitivity of the mantle source with respect to subduction-related enrichment processes, whereas Pb, K, Sr, Ba, Rb, Th, U, P2O5, and LREE are contributed by hydrous or supercritical fluid(s) and sediment melts that are added to the subarc mantle. Fijian shoshonitic suites situated ˜150 km apart display a wide range of Nb/Yb (0.3-4.3), implying that there is significant spatial heterogeneity in the sub-Fijian mantle with respect to the ambient fertility of mantle sources independent of subduction-related enrichment. The range in incompatible element ratios (e.g., Th/Nb, U/Nb, Ba/Th, Ba/La, P/Nd, and Ce/Pb) displayed by Fijian shoshonitic suites cannot reflect addition of the same subduction-derived component to variably enriched subarc mantle sources. Differences in the relative amount of fluid versus sediment melt and potentially the composition of the subducted sediment are required to explain the data. The greater overall subduction-related enrichment in Fijian shoshonites relative to calk-alkaline and tholeiitic arc magmas is attributed to a melt generation process involving low-degree partial melting of metsomatized subarc

  16. Adult thoracic primitive neuroectodermal tumor - clinical, radiological and pathological features; Tumor neuroectodermico primitivo toracico em adulto

    Energy Technology Data Exchange (ETDEWEB)

    Setubal, Roger; Santos, Leynalze Lins Ramos; Georges, Silvana Habib; Souza, Ricardo Pires de [Hospital Heliopolis, Sao Paulo, SP (Brazil). Servico de Diagnostico por Imagem; Menezes, Yara de [Hospital heliopolis, Sao Paulo, SP (Brazil). Servico de Patologia; Gomes, Marcio Rogerio Alcala; Mayo, Suzete Varela; Leiro, Luis Carlos Filgueira [Hospital Heliopolis, Sao Paulo, SP (Brazil). Servico de Pneumologia e Cirurgia Toracica

    1997-03-01

    Precise diagnosis of small round cell tumors, which include the thoracic primitive neuroectodermal tumor, is often a challenge to the clinical, oncologist, radiologist and pathologist. Different terms have been used to designate these tumors, depending on their location and extent of neural differentiation. With the progress of immuno-histochemical and cytogenetic diagnosis method, some of this tumors are now classified a unique clinical entity with several locations and mode of presentation. Therefore, tumors-like peripheral neuro epithelioma, Askin`s tumor, adult neuroblastoma, and primitive neuroectodermal tumor are now named peripheral primitive neuroectodermal tumor. The most common location of peripheral primitive neuroectodermal tumor is the thorax, and the mean age are close of the adolescence. This study reports the clinical, radiological and pathological features of 5 adults (3 men and 2 women) seen at the Hospital Heliopolis, Sao Paulo, SP Brazil, between 1991 and 1995 (5 years), with diagnosis of peripheral primitive neuroectodermal tumor made by immuno-histochemical and pathological studies. The mean age of the patients was 34 years, ranged between 17 and 57 years, and the most common location was the chest wall (n=3), followed by the posterior mediastinum (n=2). All the patients were symptomatic and undergone plain films and computed tomography. (author) 12 refs., 5 figs.

  17. Boolean operations with implicit and parametric representation of primitives using R-functions.

    Science.gov (United States)

    Fougerolle, Yohan D; Gribok, Andrei; Foufou, Sebti; Truchetet, Frédéric; Abidi, Mongi A

    2005-01-01

    We present a new and efficient algorithm to accurately polygonize an implicit surface generated by multiple Boolean operations with globally deformed primitives. Our algorithm is special in the sense that it can be applied to objects with both an implicit and a parametric representation, such as superquadrics, supershapes, and Dupin cyclides. The input is a Constructive Solid Geometry tree (CSG tree) that contains the Boolean operations, the parameters of the primitives, and the global deformations. At each node of the CSG tree, the implicit formulations of the subtrees are used to quickly determine the parts to be transmitted to the parent node, while the primitives' parametric definition are used to refine an intermediary mesh around the intersection curves. The output is both an implicit equation and a mesh representing its solution. For the resulting object, an implicit equation with guaranteed differential properties is obtained by simple combinations of the primitives' implicit equations using R-functions. Depending on the chosen R-function, this equation is continuous and can be differentiable everywhere. The primitives' parametric representations are used to directly polygonize the resulting surface by generating vertices that belong exactly to the zero-set of the resulting implicit equation. The proposed approach has many potential applications, ranging from mechanical engineering to shape recognition and data compression. Examples of complex objects are presented and commented on to show the potential of our approach for shape modeling.

  18. Learned graphical models for probabilistic planning provide a new class of movement primitives.

    Science.gov (United States)

    Rückert, Elmar A; Neumann, Gerhard; Toussaint, Marc; Maass, Wolfgang

    2012-01-01

    BIOLOGICAL MOVEMENT GENERATION COMBINES THREE INTERESTING ASPECTS: its modular organization in movement primitives (MPs), its characteristics of stochastic optimality under perturbations, and its efficiency in terms of learning. A common approach to motor skill learning is to endow the primitives with dynamical systems. Here, the parameters of the primitive indirectly define the shape of a reference trajectory. We propose an alternative MP representation based on probabilistic inference in learned graphical models with new and interesting properties that complies with salient features of biological movement control. Instead of endowing the primitives with dynamical systems, we propose to endow MPs with an intrinsic probabilistic planning system, integrating the power of stochastic optimal control (SOC) methods within a MP. The parameterization of the primitive is a graphical model that represents the dynamics and intrinsic cost function such that inference in this graphical model yields the control policy. We parameterize the intrinsic cost function using task-relevant features, such as the importance of passing through certain via-points. The system dynamics as well as intrinsic cost function parameters are learned in a reinforcement learning (RL) setting. We evaluate our approach on a complex 4-link balancing task. Our experiments show that our movement representation facilitates learning significantly and leads to better generalization to new task settings without re-learning.

  19. Sunset Song:An Elegy for the Primitive Golden Age%《落日之歌》:原始黄金时代的挽歌

    Institute of Scientific and Technical Information of China (English)

    胡怡君

    2012-01-01

    The representative novel of the twentieth century Scottish writer Lewis Grassic Gibbon,Sunset Song, unfolds a historical scene of the transition from the old to the new in a Scottish village. Based on diffu- sionism and some ideas from the Scottish Enlightenment movement, he shows in the novel a sentimental at- tachment to the primitive golden age and at the same time the hopelessness when witnessing the destruction modern civilization wrought to the old life style. In the novel, the primitive golden age represented by the earth is impinged upon and then replaced by modern civilization. Gibbon's novel thus could be treated as an elegy for the primitive golden age.%20世纪初苏格兰作家刘易斯.格拉斯科·吉本的代表作《落日之歌》展示了一幅苏格兰农村新旧时代交替的图景。他在作品中表达了对原始农耕社会的眷恋之情,同时也表现了在现代工业文明给旧生活方式带来冲击时人的无奈和悲剧。小说中土地代表着吉本眼中的原始黄金时代,土地与现代文明诸多因素的冲突一一反映在小说情节中。整本小说可视为对原始黄金时代的一曲挽歌。

  20. The earth as a planet - Paradigms and paradoxes

    Science.gov (United States)

    Anderson, D. L.

    1984-01-01

    The independent growth of the various branches of the earth sciences in the past two decades has led to a divergence of geophysical, geochemical, geological, and planetological models for the composition and evolution of a terrestrial planet. Evidence for differentiation and volcanism on small planets and a magma ocean on the moon contrasts with hypotheses for a mostly primitive, still undifferentiated, and homogeneous terrestrial mantle. In comparison with the moon, the earth has an extraordinarily thin crust. The geoid, which should reflect convection in the mantle, is apparently unrelated to the current distribution of continents and oceanic ridges. If the earth is deformable, the whole mantle should wander relative to the axis of rotation, but the implications of this are seldom discussed. The proposal of a mantle rich in olivine violates expectations based on evidence from extraterrestrial sources. These and other paradoxes force a reexamination of some long-held assumptions.

  1. Rare Earth Market Review

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ Oversupply of rare earths led to the significant price drop of rare earth mineral products and separated products in Chinese domestic market. To stabilize the price, prevent waste of resources, further improve regulation capability on domestic rare earth market and rare earth price and maintain sustaining and healthy development of rare earth industry, partial rare earth producers in Baotou and Jiangxi province projected to cease the production for one month.

  2. Plausible antioxidant biomechanics and anticonvulsant pharmacological activity of brain-targeted β-carotene nanoparticles.

    Science.gov (United States)

    Yusuf, Mohammad; Khan, Riaz A; Khan, Maria; Ahmed, Bahar

    2012-01-01

    increased in P-80-BCNP to 231.0 ± 16.30 seconds, as compared to PTZ (120.10 ± 4.50 seconds) and placebo control (120.30 ± 7.4 seconds). The results of this study demonstrate a plausible novel anticonvulsant activity of β-carotene at a low dose of 2 mg/kg, with brain-targeted nanodelivery, thus increasing its bioavailability and stability.

  3. Plausibility check of a redesigned rain-on-snow simulator (RASA)

    Science.gov (United States)

    Rössler, Ole; Probst, Sabine; Weingartner, Rolf

    2016-04-01

    Rain-on-snow events are fascinating but still not completely understood processes. Although, several studies and equations have been published since decades that describe past events and theoretical descriptions, empirical data of what is happening in the snow cover is far less available. A way to fill this gap of empirical data, rain-on-snow-simulators might be of help. In 2013, Juras et al. published their inspiring idea of a portable rain-on-snow simulator. The huge advantage of this devise - in contrast to other purely field-based experiments - are their fixed, and mostly standardized conditions and the possibility to measure all required data to monitor the water fluxes and melting processes at a time. Mounted in a convenient location, a large number of experiments are relatively easy conductible. We applied and further developed the original device and plausified the results of this redesigned version, called RASA. The principal design was borrowed from the original version being a frame with a sprinkler on top and a snow sample in a box at the bottom, from which the outflow is measured with a tipping gauge. We added a moving sprinkling plate to ensure a uniform distribution of raindrops on the snow, and - most importantly - we suspended the watered snow sampled on weighting cells. The latter enables to continuous measurement of the snow sample throughout the experiment and thus the indirect quantification of liquid water saturation, water holding capacity, and snowmelt amount via balance equations. As it is remains unclear if this device is capable to reproduce known processes, a hypothesis based plausibility check was accomplished. Thus, eight hypothesizes were derived from literature and tested in 28 experiments with the RASA mounted at 2000 m elevation. In general, we were able to reproduce most of the hypotheses. The RASA proved to be a very valuable device that can generate suitable results and has the potential to extend the empirical-experimental data

  4. Exploring apposite therapeutic target for apoptosis in filarial parasite: a plausible hypothesis.

    Science.gov (United States)

    Hande, Sneha; Goswami, Kalyan; Jena, Lingaraj; Reddy, Maryada Venkata Rami

    2014-03-01

    Human lymphatic filariasis is a parasitic disease with profound socioeconomic encumbrance owing to its associated disability, affecting predominantly but not limited to the developing nations of tropics and subtropics. There are several technical issues like poor therapeutic and preventive repertoire as well as administrative and infrastructural limitations which jeopardize the salvage measures and further complicate the plight. Therefore, considering the gravity of the problem, WHO has mandated (under tropical disease research scheme) for placing emphasis on validation of novel therapeutic targets against this disease with the unfortunate tag of 'neglected tropical disease'. However, dearth of knowledge of parasite biology viciously coupled with difficulty of access to parasitic material from suitable animal model along with growing cost burden of high end research poses formidable challenge. Based on the recent research evidences, here we propose a premise with targeted apoptotic impact as a novel rationale to be exploited towards anti-parasitic drug development. The new era of bioinformatics ushers in new optimism with a wide range of genomic and proteomic database in public domain. Such platform might offer wonders for drug research, but needs highly selective criterion specificity. In order to test our hypothesis presumptively, we deployed a scheme for identification of target proteins from filarial parasitic origin through wide database search with precise criteria of non-homology against the host along with functional essentiality for the parasite. Further screening for proteins with growth potential from such list of essential non-homologous proteins was undertaken to mine out suitable representative target for ensuing apoptotic impact though effective inhibitors. A unique protein enzyme, RNA dependent RNA polymerase, which besides its vital role in RNA virus is believed to have regulatory role in gene expression, emerged as a plausible target. This protein

  5. Lead-induced SCC of alloy 600 in plausible steam generator crevice environments

    Energy Technology Data Exchange (ETDEWEB)

    Wright, M.D. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada); Manolescu, A. [Ontario Hydro Technologies, Toronto, Ontario (Canada); Mirzai, M. [Ontario Hydro, Toronto, Ontario (Canada)

    1998-07-01

    Laboratory stress corrosion cracking (SCC) test environments developed to simulate representative BNGS-A steam generator (SG) crevice chemistries have been used to determine the susceptibility of Alloy 600 to lead-induced SCC under plausible SG conditions. Test environments were based on plant SG hideout return data and analysis of removed tubes and deposits. Deviations from the normal near neutral crevice pH environment were considered to simulate possible faulted excursion crevice chemistry and to bound the postulated crevice pH range of 3-9 (at temperature). The effect of lead contamination up to 1000 ppm, but with an emphasis on the 100 to 500 ppm range, was determined. SCC susceptibility was investigated using constant extension rate tensile (CERT) tests and encapsulated C-ring tests. CERT tests were performed at 305 degrees C on tubing representative of BNGS-A SG U-bends. The C-ring test method allowed a wider test matrix covering three temperatures (280, 304 and 315 degrees C), three strain levels (0.2%, 2% and 4%) and tubing representative of U-bends plus tubing given a simulated stress relief to represent material at the tubesheet. The results of this test program confirmed that in the absence of lead contamination, cracking does not occur in these concentrated, 3.3 to 8.9 pH range, crevice environments. Also, it appears that the concentrated crevice environments suppress lead-induced cracking relative to that seen in all-volatile-treatment (AVT) water. For the (static) C-ring tests, lead-induced SCC was only produced in the near-neutral crevice environment and was more severe at 500 ppm than 100 ppm PbO. This trend was also observed in CERT tests but some cracking/grain boundary attack occurred in acidic (pH 3.3) and alkaline (pH 8.9) environments. The C-ring tests indicated that a certain amount of resistance to cracking was imparted by simulated stress relief of the tubing. This heat treatment, confirmed to have resulted in sensitization, promoted

  6. Lead-induced stress-corrosion cracking of alloy 600 in plausible steam generator crevice environments

    Energy Technology Data Exchange (ETDEWEB)

    Wright, M.D. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada); Manolescu, A. [Ontario Hydro Technologies, Toronto, Ontario (Canada); Mirzai, M. [Ontario Hydro, Toronto, Ontario (Canada)

    1999-03-01

    Laboratory stress-corrosion cracking (SCC) test environments were developed to simulate crevice chemistries representative of Bruce Nuclear Generating Station A (BNPD A) steam generators (SGs); these test environments were used to determine the susceptibility of Alloy 600 to lead-induced SCC under plausible SG conditions. Test environments were based on plant SG hideout return data and analysis of removed tubes and deposits. Deviations from the normal near-neutral crevice pH environment were considered to simulate possible faulted excursion crevice chemistry and to bound the postulated crevice pH range of 3 to 9 (at temperature). The effect of lead contamination up to 1000 ppm, but with an emphasis on the 100- to 500-ppm range, was determined. SCC susceptibility was investigated using constant extension rate tensile (CERT) tests and encapsulated C-ring tests. CERT tests were performed at 305 degrees C on tubing representative of BNPD A SG U-bends. The C-ring test method allowed a wider test matrix, covering 3 temperatures (280 degrees C, 304 degrees C and 315 degrees C), 3 strain levels (0.2%, 2% and 4%), and tubing representative of U-bends plus tubing given a simulated stress relief to represent material at the tube sheet. The results of this test program confirmed that in the absence of lead contamination, cracking does not occur in these concentrated, 3.3 to 8.9 pH range, crevice environments. Also, it appears that the concentrated crevice environments suppress lead-induced cracking relative to that seen in all-volatile-treatment (AVT) water. For the (static) C-ring tests, lead-induced SCC was only produced in the near-neutral crevice environment and was more severe at 500 ppm than at 100 ppm PbO. This trend was also observed in CERT tests, but some cracking-grain boundary attack occurred in acidic (pH 3.3) and alkaline (pH 8.9) environments. The C-ring tests indicated that a certain amount of resistance to cracking was imparted by simulated stress relief of

  7. Method for concurrent execution of primitive operations by dynamically assigning operations based upon computational marked graph and availability of data

    Science.gov (United States)

    Stoughton, John W. (Inventor); Mielke, Roland V. (Inventor)

    1990-01-01

    Computationally complex primitive operations of an algorithm are executed concurrently in a plurality of functional units under the control of an assignment manager. The algorithm is preferably defined as a computationally marked graph contianing data status edges (paths) corresponding to each of the data flow edges. The assignment manager assigns primitive operations to the functional units and monitors completion of the primitive operations to determine data availability using the computational marked graph of the algorithm. All data accessing of the primitive operations is performed by the functional units independently of the assignment manager.

  8. The theoretical plausibility of central pit crater formation via melt drainage

    Science.gov (United States)

    Elder, Catherine M.; Bray, Veronica J.; Melosh, H. Jay

    2012-11-01

    Central pit craters are seen in large craters on some icy satellites and on Mars. We investigate the hypothesis that central pits form when impact melt drains into fractures beneath the impact crater. For this process to occur, the volume of melt generated during the impact, the volume of void space in fractures beneath the impact crater, and the volume of melt able to drain before the fractures freeze shut all must exceed the volume of the observed central pits. We estimate the volume of melt generated using results from previous numerical modeling studies. The fracture volume is estimated using gravity anomalies over terrestrial craters. To estimate the amount of melt able to drain before freezing, we consider flow through plane parallel fractures. These calculations all suggest that enough liquid water could drain into fractured ice beneath a crater on Ganymede to form a central pit. On Earth and the Moon, silicate impact melt will freeze before a large volume is able to drain, so we do not expect to see central pits in impact craters in targets with no ice. In summary, we find our calculations are consistent with observed central pits in craters on Ganymede and the lack of central pits in craters on Earth and the Moon.

  9. [Mouse teratocarcinoma: differentiation in cultures of a multipotential primitive cell line (author's transl)].

    Science.gov (United States)

    Nicolas, J F; Dubois, P; Jakob, H; Gaillard, J; Jacob, F

    1975-01-01

    A line of primitive cells of teratocarcinoma is able of differentiating during in vitro cultures. The differentiated cell types correspond to derivatives of the three germ layers. They appear according to a reproducible schedule. The differentiated cell types exhibit a normal karyotype. They have lost their tumorigenicity and have a limited life span. Agregates containing various numbers of primitive cells have been prepared and plated in culture dishes. Their study shows that the first differentiated cell types appear only when the agregates are greater than a certain critical mass. Primitive cells carry on their surface the F9 but not the H-2 antigen. During differentiation in culture, the H-2 antigen appears rapidly on certain cells. The fraction of H-2-carrying cells increases as a function of time while that of F9-carrying cells decreases.

  10. Synthesis of New Dynamic Movement Primitives Through Search in a Hierarchical Database of Example Movements

    Directory of Open Access Journals (Sweden)

    Miha Deniša

    2015-10-01

    Full Text Available This paper presents a novel approach to discovering motor primitives in a hierarchical database of example trajectories. An initial set of example trajectories is obtained by human demonstration. The trajectories are clustered and organized in a binary tree-like hierarchical structure, from which transition graphs at different levels of granularity are constructed. A novel procedure for searching in this hierarchical structure is presented. It can exploit the interdependencies between movements and can discover new series of partial paths. From these partial paths, complete new movements are generated by encoding them as dynamic movement primitives. In this way, the number of example trajectories that must be acquired with the assistance of a human teacher can be reduced. By combining the results of the hierarchical search with statistical generalization techniques, a complete representation of new, not directly demonstrated, movement primitives can be generated.

  11. A new family of primitive mammal from the Mesozoic of western Liaoning, China

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A fairly well-preserved specimen of a new primitive mammal, Repenomamus robustus gen. et sp. nov., has been described from the Yixian Formation (Lower Cretaceous), western Liaoning, China. This animal has several derived characteristics, such as well-developed dentary/squamosal articulation, reduced number of tooth, differentiation of premolars and molars in postcanine teeth, presence of a dorsal process of the premaxilla that is not in contact with the nasal, closed medial wall of the orbit, and presence of fingerlike promontorium on the petrosal. It also retains some primitive reptile-like features. It is the most primitive taxon among the three mammals known from the Jehol Biota, and also represents the largest mammal of Mesozoic age over the world.

  12. Light Scattering and Thermal Emission by Primitive Dust Particles in Planetary Systems

    CERN Document Server

    Kimura, Hiroshi; Li, Aigen; Lebreton, Jérémy

    2016-01-01

    This review focuses on numerical approaches to deducing the light-scattering and thermal-emission properties of primitive dust particles in planetary systems from astronomical observations. The particles are agglomerates of small grains with sizes comparable to visible wavelength and compositions being mainly magnesium-rich silicates, iron-bearing metals, and organic refractory materials in pristine phases. These unique characteristics of primitive dust particles reflect their formation and evolution around main-sequence stars of essentially solar composition. The development of light-scattering theories has been offering powerful tools to make a thorough investigation of light scattering and thermal emission by primitive dust agglomerates in such a circumstellar environment. In particular, the discrete dipole approximation, the T-matrix method, and effective medium approximations are the most popular techniques for practical use in astronomy. Numerical simulations of light scattering and thermal emission by ...

  13. Spontaneous cerebellar primitive neuroectodermal tumor in a juvenile cynomolgus monkey (Macaca fascicularis).

    Science.gov (United States)

    Mukaratirwa, Sydney; Rogerson, Petrina; Blanco, Ana L; Naylor, Stuart W; Bradley, Alys

    2012-08-01

    A neoplastic mass compressing the left cerebellar hemisphere and hindbrain was observed at trimming in a 3½-year-old male cynomolgus monkey from a control dose group. Microscopically, the neoplastic mass was nonencapsulated, invasive, and showed two morphological patterns. The predominant area consisted of densely packed undifferentiated, polygonal to spindle cells arranged in vague sheets supported by a scant fibrovascular stroma. The other area was less cellular and composed of round neoplastic cells separated by eosinophilic fibrillar material. Immunohistochemical staining for vimentin, synaptophysin, glial fibrillary acidic protein, neuron-specific enolase, neurofilament, and S-100 confirmed the presence of primitive undifferentiated neuroectodermal cells and some cells with neuronal or glial differentiation. On the basis of histopathology and immunohistochemical findings, a diagnosis of cerebellar primitive neuroectodermal tumor with neuronal and glial differentiation was made. Primitive neuroectodermal tumors are rare in animals including nonhuman primates; this is the first published report in this species.

  14. Primitive neuroectodermal tumor in a mixed germ cell tumor - A rare case report

    Directory of Open Access Journals (Sweden)

    Khushboo Dewan

    2015-01-01

    Full Text Available A rare case of testicular tumor in a 20-year-old male with Primitive Neuroectodermal Tumor (PNET was reported. Imaging studies showed a large heterogenous mass in the right scrotal sac and a large retroperitoneal mass with metastasis in the lung and liver. Serum alpha fetoprotein (AFP was markedly elevated with moderate increase in serum β-human chorionic gonadotropin (hCG levels. After orchidectomy, a histological diagnosis of mixed germ cell tumor-teratoma with primitive neuroectodermal, embryonal, and yolk sac components was made. Some scattered embryoid bodies representative of primitive germ cell tumor were also present. Morphological diversity including PNET prompted the authors to report this case as PNET points toward a poor prognosis.

  15. Primitive neuroectodermal tumors in the posterior fossa: excluding medulloblastoma based on pathology

    Energy Technology Data Exchange (ETDEWEB)

    Suh, Kyung Jin; Kim, Tae Hun; Kim, Yong Joo; Kang, Duk Sik; Shon, Youn Kyung [College of Medicine, Kyungpook National University, Daegu (Korea, Republic of); Kim, Sun Young [College of Medicine, Youngnam University, Daegu (Korea, Republic of)

    1992-01-15

    Four children, with histopathologically confirmed posterior fossa primitive neuroectodermal tumors, were examined by plain radiography, computed tomography (CT) and cerebral angiography. The homogeneously well enhanced solid mass in the midline of the posterior fossa and hydrocephalus of various degree were seen on all CT scans. One case had calcifications and another case had low density areas in the tumor mass. Three cerebral angiograms showed vascular displacement without tumor vascularities. Unfortunately, these CT and angiography findings are not specific for primitive neuroectodermal tumors, as similar findings are seen in medulloblastoma, ependymoma and other tumors. Therefore, we think that the primitive neuroectodermal tumors should be included in the differential diagnosis when a well enhanced solid mass in the midline posterior fossa is seen on CT scan in children.

  16. Global Strong Well-Posedness of the Three Dimensional Primitive Equations in {L^p}-Spaces

    Science.gov (United States)

    Hieber, Matthias; Kashiwabara, Takahito

    2016-09-01

    In this article, an {L^p}-approach to the primitive equations is developed. In particular, it is shown that the three dimensional primitive equations admit a unique, global strong solution for all initial data {a in [X_p,D(A_p)]_{1/p}} provided {p in [6/5,infty)}. To this end, the hydrostatic Stokes operator {A_p} defined on {X_p}, the subspace of {L^p} associated with the hydrostatic Helmholtz projection, is introduced and investigated. Choosing {p} large, one obtains global well-posedness of the primitive equations for strong solutions for initial data {a} having less differentiability properties than {H^1}, hereby generalizing in particular a result by Cao and Titi (Ann Math 166:245-267, 2007) to the case of non-smooth initial data.

  17. Primitive potentials and bounded solutions of the KdV equation

    Science.gov (United States)

    Dyachenko, S.; Zakharov, D.; Zakharov, V.

    2016-10-01

    We construct a broad class of bounded potentials of the one-dimensional Schrödinger operator that have the same spectral structure as periodic finite-gap potentials, but that are neither periodic nor quasi-periodic. Such potentials, which we call primitive, are non-uniquely parametrized by a pair of positive Hölder continuous functions defined on the allowed bands. Primitive potentials are constructed as solutions of a system of singular integral equations, which can be efficiently solved numerically. Simulations show that these potentials can have a disordered structure. Primitive potentials generate a broad class of bounded non-vanishing solutions of the KdV hierarchy, and we interpret them as an example of integrable turbulence in the framework of the KdV equation.

  18. From the Big Bang to the life in the primitive seas. (Spanish Title: Desde la Gran Explosión hasta la vida en los mares primitivos)

    Science.gov (United States)

    Esteban, S. B.

    Man has always wondered about the origins of humanity, life, and the world around him. The Earth crust is a vast and natural archive, and its rocks represent the pages of the most documented events in the geological past. These rocks hold large amounts of information about the Earth history, whose age is estimated to be 4,600 million years. Historical Geology seeks to bring together the knowledge of the origin of the Universe as well as the origin of Earth as a member of the Solar System. The Big Bang theory supposes that the Universe began with a huge explosion. In the Earth's history it is possible to differentiate the biological events from the physical ones. The physical events are geographical and environmental transformations. The biological events are related to life on Earth. There are evidences of biological processes back to 3,500 million years ago. At the beginning, the conditions on Earth were catastrophic and unstable. At this stage, the first signs of life were the molecules that started to take energy from the sunlight and the chemical products. It was not a simple accumulation of gradual biological forms, but was accompanied by episodic innovations that allowed increasing complexity and greater use of ecospace. Some of these innovations are shown by certain groups of primitive arthropods adapted to live in oxygen-poor, deep marine environments. These arthropods have been found in 500 million-year-old rocks in northwestern Argentina (provinces of Jujuy and La Rioja), indicating the presence of oxygen-poor seas in that region.

  19. Origins of gene, genetic code, protein and life: comprehensive view of life systems from a GNC-SNS primitive genetic code hypothesis

    Indian Academy of Sciences (India)

    K Ikehara

    2002-03-01

    We have investigated the origin of genes, the genetic code, proteins and life using six indices (hydropathy, -helix, -sheet and -turn formabilities, acidic amino acid content and basic amino acid content) necessary for appropriate three-dimensional structure formation of globular proteins. From the analysis of microbial genes, we have concluded that newly-born genes are products of nonstop frames (NSF) on antisense strands of microbial GC-rich genes [GC-NSF(a)] and from SNS repeating sequences [(SNS)n] similar to the GC-NSF(a) (S and N mean G or C and either of four bases, respectively). We have also proposed that the universal genetic code used by most organisms on the earth presently could be derived from a GNC-SNS primitive genetic code. We have further presented the [GADV]-protein world hypothesis of the origin of life as well as a hypothesis of protein production, suggesting that proteins were originally produced by random peptide formation of amino acids restricted in specific amino acid compositions termed as GNC-, SNS- and GC-NSF(a)-0th order structures of proteins. The [GADV]-protein world hypothesis is primarily derived from the GNC-primitive genetic code hypothesis. It is also expected that basic properties of extant genes and proteins could be revealed by considerations based on the scenario with four stages.

  20. The evolution of amniote gastrulation: the blastopore-primitive streak transition.

    Science.gov (United States)

    Stower, Matthew J; Bertocchini, Federica

    2017-03-01

    In the animal kingdom, gastrulation, the process by which the primary germ layers are formed involves a dramatic transformation in the topology of the cells that give rise to all of the tissues of the adult. Initially formed as a mono-layer, this tissue, the epiblast, becomes subdivided through the internalization of cells, thereby forming a two (bi-laminar) or three (tri-laminar) layered embryo. This morphogenetic process coordinates the development of the fundamental body plan and the three-body axes (antero-posterior, dorso-ventral, and left-right) and begins a fundamental segregation of cells toward divergent developmental fates. In humans and other mammals, as well as in avians, gastrulating cells internalize along a structure, called the primitive streak, which builds from the periphery toward the center of the embryo. How these morphogenetic movements are orchestrated and evolved has been a question for developmental biologists for many years. Is the primitive streak a feature shared by the whole amniote clade? Insights from reptiles suggest that the primitive streak arose independently in mammals and avians, while the reptilian internalization site is a structure half-way between an amphibian blastopore and a primitive streak. The molecular machinery driving primitive streak formation has been partially dissected using mainly the avian embryo, revealing a paramount role of the planar cell polarity (PCP) pathway in streak formation. How did the employment of this machinery evolve? The reptilian branch of the amniote clade might provide us with useful tools to investigate the evolution of the amniote internalization site up to the formation of the primitive streak. WIREs Dev Biol 2017, 6:e262. doi: 10.1002/wdev.262 For further resources related to this article, please visit the WIREs website.

  1. Strict constraints on 2D primitive pairs for engineering symbol recognition:Theory and application

    Institute of Scientific and Technical Information of China (English)

    LI Ting; QIU XianJie; HUANG He; WANG ZhaoQi

    2012-01-01

    Geometric constraints on the line-line pair,line-arc pair and arc-arc pair are proposed.The constraints are able to encode the geometric relations between lines,arcs and circles.A geometric proof is presented to demonstrate that the constraints are stable under translation,rotation,uniform scaling or reflection of the primitive pairs.Based on the constraints,an algorithm for recognizing symbols in drawings is developed.Experimental results show that,compared with three other methods,our method can distinguish more primitive pairs and has higher accuracy in engineering symbol recognition.

  2. Multimodality treatment approach in management of primary peripheral primitive neuroectodermal tumor of the orbit

    Directory of Open Access Journals (Sweden)

    Kim Usha

    2009-01-01

    Full Text Available Primitive neuroectodermal tumor is a small round cell malignancy which rarely involves the orbit. We report a case of a two-year old male child presenting as unilateral eccentric proptosis with extraconal and intraconal mass, diagnosed as primary peripheral primitive neuroectodermal tumor (pPPNET on histopathology and immunohistochemistry. There is no defined consensus in the management of these tumors due to its rare presentation. We describe its distinguishing features with emphasis on multimodal and aggressive treatment approach which ensures appropriate management of these cases.

  3. A PICKED SAMPLE TO THE FOOTPRINT OF PRIMITIVE INDIVIDUALISM OF RECENT DATE ART: BASQUIAT

    Directory of Open Access Journals (Sweden)

    Ozgur TOSUN

    2015-09-01

    Full Text Available Through the culturel history, meaning of art and art object have been queried and these researchs have emerged thesis and antithesis. Fundamentaly, this article aim to comparison interaction and/or conflict with mathematical rationalist art and primitive/heuristical/romantic art. In this context, effects of primitive and experssive art to the nowadays’ art perception are examined to envolve out of Basquiat and neo expressionism. Entailment of expressive art in contemporary art is researched for answers for questions in terms of cultural and genetic heritage of art and instinctive origins of making art object.

  4. Is air pollution a plausible candidate for prenatal exposure in autism spectrum disorder (ASD)? : a systematic review / y Dhanashree Vernekar

    OpenAIRE

    Vernekar, Dhanashree

    2013-01-01

    Objective: To present a systematic review of existing literature that investigates biological plausibility of prenatal hazardous air pollutants’ (HAPs) exposure, in the etiology of autism spectrum disorder (ASD) and related outcomes. Method: Electronic databases Pubmed, Biomed Central and National Database for Autism Research, and grey literature pertaining to air pollution association with ASD and related outcomes were searched using specific keywords. The search included 190 HAPs as defi...

  5. Effective Teacher Practice on the Plausibility of Human-Induced Climate Change

    Science.gov (United States)

    Niepold, F.; Sinatra, G. M.; Lombardi, D.

    2013-12-01

    Climate change education programs in the United States seek to promote a deeper understanding of the science of climate change, behavior change and stewardship, and support informed decision making by individuals, organizations, and institutions--all of which are summarized under the term 'climate literacy.' The ultimate goal of climate literacy is to enable actors to address climate change, both in terms of stabilizing and reducing emissions of greenhouse gases, but also an increased capacity to prepare for the consequences and opportunities of climate change. However, the long-term nature of climate change and the required societal response involve the changing students' ideas about controversial scientific issues which presents unique challenges for educators (Lombardi & Sinatra, 2010; Sinatra & Mason, 2008). This session will explore how the United States educational efforts focus on three distinct, but related, areas: the science of climate change, the human-climate interaction, and using climate education to promote informed decision making. Each of these approaches are represented in the Atlas of Science Literacy (American Association for the Advancement of Science, 2007) and in the conceptual framework for science education developed at the National Research Council (NRC) in 2012. Instruction to develop these fundamental thinking skills (e.g., critical evaluation and plausibility reappraisal) has been called for by the Next Generation Science Standards (NGSS) (Achieve, 2013), an innovative and research based way to address climate change education within the decentralized U.S. education system. However, the promise of the NGSS is that students will have more time to build mastery on the subjects, but the form of that instructional practice has been show to be critical. Research has show that effective instructional activities that promote evaluation of evidence improve students' understanding and acceptance toward the scientifically accepted model of human

  6. Plausible antioxidant biomechanics and anticonvulsant pharmacological activity of brain-targeted β-carotene nanoparticles

    Directory of Open Access Journals (Sweden)

    Yusuf M

    2012-08-01

    general tonic–clonic seizures reduced significantly to 2.90 ± 0.98 seconds by the use of BCNP and was further reduced on P-80-BCNP to 1.20 ± 0.20 seconds as compared to PTZ control and PTZ-placebo control (8.09 ± 0.26 seconds. General tonic–clonic seizures latency was increased significantly to 191.0 ± 9.80 seconds in BCNP and was further increased in P-80-BCNP to 231.0 ± 16.30 seconds, as compared to PTZ (120.10 ± 4.50 seconds and placebo control (120.30 ± 7.4 seconds. The results of this study demonstrate a plausible novel anticonvulsant activity of β-carotene at a low dose of 2 mg/kg, with brain-targeted nanodelivery, thus increasing its bioavailability and stability.Keywords: anticonvulsant, blood–brain barrier (BBB, targeted brain delivery, polysorbate-80-coated β-carotene nanoparticles (P-80-BCNP, maximal electroshock seizure (MES, pentylenetetrazole (PTZ

  7. Vulnerabilities to agricultural production shocks: An extreme, plausible scenario for assessment of risk for the insurance sector

    Directory of Open Access Journals (Sweden)

    Tobias Lunt

    2016-01-01

    Full Text Available Climate risks pose a threat to the function of the global food system and therefore also a hazard to the global financial sector, the stability of governments, and the food security and health of the world’s population. This paper presents a method to assess plausible impacts of an agricultural production shock and potential materiality for global insurers. A hypothetical, near-term, plausible, extreme scenario was developed based upon modules of historical agricultural production shocks, linked under a warm phase El Niño-Southern Oscillation (ENSO meteorological framework. The scenario included teleconnected floods and droughts in disparate agricultural production regions around the world, as well as plausible, extreme biotic shocks. In this scenario, global crop yield declines of 10% for maize, 11% for soy, 7% for wheat and 7% for rice result in quadrupled commodity prices and commodity stock fluctuations, civil unrest, significant negative humanitarian consequences and major financial losses worldwide. This work illustrates a need for the scientific community to partner across sectors and industries towards better-integrated global data, modeling and analytical capacities, to better respond to and prepare for concurrent agricultural failure. Governments, humanitarian organizations and the private sector collectively may recognize significant benefits from more systematic assessment of exposure to agricultural climate risk.

  8. Earth from Above

    Science.gov (United States)

    Stahley, Tom

    2006-01-01

    Google Earth is a free online software that provides a virtual view of Earth. Using Google Earth, students can view Earth by hovering over features and locations they preselect or by serendipitously exploring locations that catch their fascination. Going beyond hovering, they can swoop forward and even tilt images to make more detailed…

  9. Rare Earth Resolution

    Institute of Scientific and Technical Information of China (English)

    Mei Xinyu

    2012-01-01

    BEFORE the early 1970s, China had no rare earth exports, and the world rare earth market was dominated by the United States, Europe and Japan. In the 1970s, China began to enter the world rare earth market and its share has picked up sharply in the following decades. Today, having the monopoly over global rare earth production, China must improve the benefits from rare earth production, not only from producing individual rare earth products, but also from mastering the intensive processing of rare earth products.

  10. Preliminary Study on Plausible Reasoning in Chemistry Teaching of Senior Middle School%高中化学合情推理教学的初步研究

    Institute of Scientific and Technical Information of China (English)

    杨健; 吴俊明; 骆红山

    2009-01-01

    合情推理(Plausible reasoning)对科学教育具重要意义.通过科学哲学、逻辑学讨论以及历史实例说明科学发现离不开合情推理,科学教育必须重视合情推理能力的培养,并对高中化学合情推理教学的可能性、对象和内容等问题进行了讨论.%Plausible reasoning is significant to science education. Scientific philosophy, logic and historical examples prove that plausible reasoning is indispensable to scientific discoveries,so science education must pay attention to the development of plausible reasoning ability of students. Moreover, it discusses the possibility, object and content of plausible reasoning teaching in chemistry of senior middle school.

  11. The ontogenetic transformation of the mesosaurid tarsus: a contribution to the origin of the primitive amniotic astragalus

    Directory of Open Access Journals (Sweden)

    Graciela Piñeiro

    2016-05-01

    Full Text Available The hypotheses about the origin of the primitive amniotic tarsus are very speculative. Early studies argued that the origin of the astragalus, one of the largest proximal bones in the tarsus of basal amniotes, was produced by either the fusion of two, three, or even four of the original tarsal bones, the intermedium, the tibiale and the proximal centralia (c4 and c3, or that the intermedium alone transforms into the primitive astragalus. More recent studies have shown that the structure of the tarsus in Captorhinus supports the former hypothesis about a fusion of the intermedium, the tibiale, the proximal centrale (c4 and eventually c3, producing a purportedly multipartite structure of the amniotic astragalus, but the issue remained contentious. Very well preserved tarsi of the Early Permian aquatic amniote Mesosaurus tenuidens Gervais, 1864–1865, which represent the most complete ontogenetic succession known for a basal amniote (the other exceptional one is provided by the Late Permian diapsid Hovasaurus boulei Piveteau, 1926, suggest that there is more than one ossification center for the astragalus and that these fuse during late embryonic stages or maybe early after birth. A non-hatched Mesosaurus in an advanced stage of development shows that the tarsus is represented by a single bone, most probably the astragalus, which seems to be formed by the suturing of three bones, here interpreted as being the intermedium, the tibiale, probably already integrated to the c4 in an earlier stage of the development, and the c3. An amniote-like tarsal structure is observed in very basal Carboniferous and Permian tetrapods such as Proterogyrinus, Gephyrostegus, the diadectids Diadectes and Orobates, some microsaurs like Tuditanus and Pantylus and possibly Westlothiana, taxa that were all considered as true amniotes in their original descriptions. Therefore, the structure of the amniotic tarsus, including the configuration of the proximal series formed by

  12. The ontogenetic transformation of the mesosaurid tarsus: a contribution to the origin of the primitive amniotic astragalus.

    Science.gov (United States)

    Piñeiro, Graciela; Núñez Demarco, Pablo; Meneghel, Melitta D

    2016-01-01

    The hypotheses about the origin of the primitive amniotic tarsus are very speculative. Early studies argued that the origin of the astragalus, one of the largest proximal bones in the tarsus of basal amniotes, was produced by either the fusion of two, three, or even four of the original tarsal bones, the intermedium, the tibiale and the proximal centralia (c4 and c3), or that the intermedium alone transforms into the primitive astragalus. More recent studies have shown that the structure of the tarsus in Captorhinus supports the former hypothesis about a fusion of the intermedium, the tibiale, the proximal centrale (c4) and eventually c3, producing a purportedly multipartite structure of the amniotic astragalus, but the issue remained contentious. Very well preserved tarsi of the Early Permian aquatic amniote Mesosaurus tenuidens Gervais, 1864-1865, which represent the most complete ontogenetic succession known for a basal amniote (the other exceptional one is provided by the Late Permian diapsid Hovasaurus boulei Piveteau, 1926), suggest that there is more than one ossification center for the astragalus and that these fuse during late embryonic stages or maybe early after birth. A non-hatched Mesosaurus in an advanced stage of development shows that the tarsus is represented by a single bone, most probably the astragalus, which seems to be formed by the suturing of three bones, here interpreted as being the intermedium, the tibiale, probably already integrated to the c4 in an earlier stage of the development, and the c3. An amniote-like tarsal structure is observed in very basal Carboniferous and Permian tetrapods such as Proterogyrinus, Gephyrostegus, the diadectids Diadectes and Orobates, some microsaurs like Tuditanus and Pantylus and possibly Westlothiana, taxa that were all considered as true amniotes in their original descriptions. Therefore, the structure of the amniotic tarsus, including the configuration of the proximal series formed by the astragalus and

  13. Primitive Liquid Water of the Solar System in an Aqueous Altered Carbonaceous Chondrite

    Science.gov (United States)

    Tsuchiyama, A.; Miyake, A.; Kitayama, A.; Matsuno, J.; Takeuchi, A.; Uesugi, K.; Suzuki, Y.; Nakano, T.; Zolensky, M. E.

    2016-01-01

    Non-destructive 3D observations of the aqueous altered CM chondrite Sutter's Mill using scanning imaging x-ray microscopy (SIXM) showed that some of calcite and enstatite grains contain two-phase inclusion, which is most probably composed of liquid water and bubbles. This water should be primitive water responsible for aqueous alteration in an asteroid in the early solar system.

  14. Persistent primitive hypoglossal artery associated with Chiari II malformation: Diagnosis and clinical implications

    Directory of Open Access Journals (Sweden)

    Gupta Mudit

    2010-01-01

    Full Text Available We present a case of persistent primitive hypoglossal artery (PPHA associated with Chiari II malformation and discuss the clinical implications. There has been one reported case of PPHA associated with Chiari 1 malformation, but none in association with Chiari II. Our patient also had a widened hypoglossal canal, with cerebrospinal fluid (CSF sac herniation through it.

  15. Primitive Neuroectodermal Tumors of Hand and Foot: Report of Two Cases

    OpenAIRE

    DEMİR, Pelin; Arikan, Murat; ÇİLEDAĞ, Nazan; AKTAŞ, ELIF; Güngör, Şafak; Arda, Kemal

    2009-01-01

    Primitive neuroectodermal tumor (PNET) of hand and foot is extremely rare. To our knowiedge, limited number of cases of typicat PNET has been reported, involving the hand orfoot. İn this report, we presented magnetic resonance imaging findings of a PNET case localized in the proximal phalanx of left foot and a case localized in distal phalanx of the right hand.

  16. Primitive ontology and quantum state in the GRW matter density theory

    CERN Document Server

    Egg, Matthias

    2014-01-01

    The paper explains in what sense the GRW matter density theory (GRWm) is a primitive ontology theory of quantum mechanics and why, thus conceived, the standard objections against the GRW formalism do not apply to GRWm. We consider the different options for conceiving the quantum state in GRWm and argue that dispositionalism is the most attractive one.

  17. Primitive Reflexes and Attention-Deficit/Hyperactivity Disorder: Developmental Origins of Classroom Dysfunction

    Science.gov (United States)

    Taylor, Myra; Houghton, Stephen; Chapman, Elaine

    2004-01-01

    The present research studied the symptomatologic overlap of AD/HD behaviours and retention of four primitive reflexes (Moro, Tonic Labyrinthine Reflex [TLR], Asymmetrical Tonic Neck Reflex [ATNR], Symmetrical Tonic Neck Reflex [STNR]) in 109 boys aged 7-10 years. Of these, 54 were diagnosed with AD/HD, 34 manifested sub-syndromal coordination,…

  18. Generation of primitive neural stem cells from human fibroblasts using a defined set of factors

    Directory of Open Access Journals (Sweden)

    Takumi Miura

    2015-11-01

    Full Text Available In mice, leukemia inhibitory factor (LIF-dependent primitive neural stem cells (NSCs have a higher neurogenic potential than bFGF-dependent definitive NSCs. Therefore, expandable primitive NSCs are required for research and for the development of therapeutic strategies for neurological diseases. There is a dearth of suitable techniques for the generation of human long-term expandable primitive NSCs. Here, we have described a method for the conversion of human fibroblasts to LIF-dependent primitive NSCs using a strategy based on techniques for the generation of induced pluripotent stem cells (iPSCs. These LIF-dependent induced NSCs (LD-iNSCs can be expanded for >100 passages. Long-term cultured LD-iNSCs demonstrated multipotent neural differentiation potential and could generate motor neurons and dopaminergic neurons, as well as astrocytes and oligodendrocytes, indicating a high level of plasticity. Furthermore, LD-iNSCs easily reverted to human iPSCs, indicating that LD-iNSCs are in an intermediate iPSC state. This method may facilitate the generation of patient-specific human neurons for studies and treatment of neurodegenerative diseases.

  19. Primitive orthogonal idempotents of Brandt semigroup algebras and Brandt semigroup codes

    OpenAIRE

    Zhang, Yi; Li, Jian-rong; Peng, Xiao-Song; Luo, Yan-Feng

    2015-01-01

    In this paper, we construct a complete set of primitive orthogonal idempotents for any finite Brandt semigroup algebra. As applications, we define a new class of codes called Brandt semigroup codes and compute the Cartan matrices of some Brandt semigroup algebras. We also study the supports, Hamming distances, and minimum weights of Brandt semigroup codes.

  20. Existence and Regularity of Invariant Measures for the Three Dimensional Stochastic Primitive Equations

    Energy Technology Data Exchange (ETDEWEB)

    Glatt-Holtz, Nathan, E-mail: negh@vt.edu [Department of Mathematics, Virginia Tech, Blacksburg, Virginia 24061 (United States); Kukavica, Igor, E-mail: kukavica@usc.edu; Ziane, Mohammed, E-mail: ziane@usc.edu [Department of Mathematics, University of Southern California, Los Angeles, California 90089 (United States); Vicol, Vlad, E-mail: vvicol@math.princeton.edu [Department of Mathematics, Princeton University, Princeton, New Jersey 08544 (United States)

    2014-05-15

    We establish the continuity of the Markovian semigroup associated with strong solutions of the stochastic 3D Primitive Equations, and prove the existence of an invariant measure. The proof is based on new moment bounds for strong solutions. The invariant measure is supported on strong solutions and is furthermore shown to have higher regularity properties.

  1. [Conformation motion equation and primitive molecular machines for electron (ion) transport in biological systems].

    Science.gov (United States)

    Shaĭtan, K V; Rubin, A B

    1982-01-01

    A general theory of electron-conformation interactions and correlation between electron transfer rates and conformational mobility are discussed on the basis of a stochastic model of protein dynamics. A set of equations is developed and solved for primitive molecular "machines". Estimation of structural parameters for the reduction of the secondary acceptor in bacterial photosynthesis is given.

  2. The MRI findings of meningeal peripheral-type primitive neuroectodermal tumors

    Institute of Scientific and Technical Information of China (English)

    李文一

    2014-01-01

    Objective To analyze the MRI features of Ewing sarcoma/peripheral primitive neuroectodermal tumors(pPNETs)arising from the meninges.Methods The MRI imaging of 9 patients with Ewing sarcoma/pPNET were reviewed retrospectively,and imaging features and pathological characteristics were analyzed.Results The age of most patients ranged from 10 to 20

  3. Primary primitive neuroectodermal tumor: An unusual cause of right ventricular intracavitary obstruction in a child

    Directory of Open Access Journals (Sweden)

    Thachil Ajit

    2008-01-01

    Full Text Available A six-year-old boy presented with a brief history suggestive of right heart failure. Investigations revealed a mass filling almost the entire right ventricle. Palliative resection of the mass was done. The operative specimen revealed a primary primitive neuroectodermal tumor of the heart, the first of its kind reported in the pediatric age group .

  4. Pediatric Primitive Neuroectodermal Tumors of the Central Nervous System Differentially Express Granzyme Inhibitors

    NARCIS (Netherlands)

    Vermeulen, Jeroen F; van Hecke, Wim; Spliet, Wim G M; Villacorta Hidalgo, José; Fisch, Paul; Broekhuizen, Roel; Bovenschen, Niels

    2016-01-01

    BACKGROUND: Central nervous system (CNS) primitive neuroectodermal tumors (PNETs) are malignant primary brain tumors that occur in young infants. Using current standard therapy, up to 80% of the children still dies from recurrent disease. Cellular immunotherapy might be key to improve overall surviv

  5. Primitive neuro-ectodermal tumor of the lung in an adult

    Directory of Open Access Journals (Sweden)

    Gaude G

    2009-01-01

    Full Text Available A rare case of a thoracic primitive neuro-ectodermal tumor in an adult is presented here. In this case, wide excision surgical excision followed by chemotherapy and radiotherapy were delivered. But due to the rapid aggressive progression of the tumor, which is the characteristic of disease, the patient died within four months after the diagnosis.

  6. Identification of novel biomarkers in pediatric primitive neuroectodermal tumors and ependymomas by proteome-wide analysis

    NARCIS (Netherlands)

    de Bont, Judith M.; den Boer, Monique L.; Kros, Johan M.; Passier, Monique M. C. J.; Reddinglus, Roel E.; Smitt, Peter A. E. Sillevis; Luider, Theo M.; Pieters, Rob

    2007-01-01

    The aim of this study was to identify aberrantly expressed proteins in pediatric primitive neuroectodermal tumors (PNETs) and ependymornas. Tumor tissue of 29 PNET and 12 ependymoma patients was subjected to 2-dimensional difference gel electrophoresis. Gel analysis resulted in 79 protein spots bein

  7. Cosmic abundance of iron and nature of primitive material in meteorites.

    Science.gov (United States)

    Kerridge, J.

    1972-01-01

    Comparison of solar abundance data with bulk analyses of type-I carbonaceous meteorites and microprobe analyses of type-I phyllosilicates. The comparison seems to lend support to Kerridge's (1971) hypothesis that the apparently primitive chemistry of such meteorites may be the result of a major component dominating the analysis and that this component may be unaltered solar system condensate.

  8. European encounters with ‘primitive art’ during the late nineteenth century

    Directory of Open Access Journals (Sweden)

    Raymond Corbey

    2015-06-01

    Full Text Available This is an introduction to the present Journal of Art Historiography’s special issue on the European reception of so-called primitive art in around 1900. It outlines the collection of objects from small-scale non-European societies and their scholarly

  9. Non-interactive Distributed Encryption : A New Primitive for Revocable Privacy

    NARCIS (Netherlands)

    Galindo, D.; Hoepman, J.H.

    2011-01-01

    In this paper we introduce and instantiate a new cryptographic primitive, called non-interactive distributed encryption, that allows a receiver to decrypt a ciphertext only if a minimum number of different senders encrypt the same plaintext. The new functionality can be seen as the dual of the

  10. Application of the zero separation theorem to the restricted primitive model of electrolyte solutions

    DEFF Research Database (Denmark)

    Sloth, Peter

    1988-01-01

    Calculations of activity coefficients by application of the zero separation theorem is discussed for the restricted primitive model of electrolyte solutions. Numerical results within the framework of the hypernetted chain approximation are given. These indicate that the bridge functions—at zero s...

  11. Naturalistic arm movements during obstacle avoidance in 3D and the identification of movement primitives.

    Science.gov (United States)

    Grimme, Britta; Lipinski, John; Schöner, Gregor

    2012-10-01

    By studying human movement in the laboratory, a number of regularities and invariants such as planarity and the principle of isochrony have been discovered. The theoretical idea has gained traction that movement may be generated from a limited set of movement primitives that would encode these invariants. In this study, we ask if invariants and movement primitives capture naturalistic human movement. Participants moved objects to target locations while avoiding obstacles using unconstrained arm movements in three dimensions. Two experiments manipulated the spatial layout of targets, obstacles, and the locations in the transport movement where an obstacle was encountered. We found that all movement trajectories were planar, with the inclination of the movement plane reflecting the obstacle constraint. The timing of the movement was consistent with both global isochrony (same movement time for variable path lengths) and local isochrony (same movement time for two components of the obstacle avoidance movement). The identified movement primitives of transport (movement from start to target position) and lift (movement perpendicular to transport within the movement plane) varied independently with obstacle conditions. Their scaling accounted for the observed double peak structure of movement speed. Overall, the observed naturalistic movement was astoundingly regular. Its decomposition into primitives suggests simple mechanisms for movement generation.

  12. Anomalous oxygen and neon isotopes in the mineral inclusions of primitive meteorites

    Energy Technology Data Exchange (ETDEWEB)

    Kuroda, P.K.; Myers, W.A. [Arkansas Univ., Fayetteville (United States). Dept. of Chem. Eng.

    1995-12-31

    A supernova explosion, which preceeded the formation of the solar system, may have acted like a gigantic gaseous diffusion plant or a centrifuge to produce the large isotopic anomalies recently observed for oxygen and neon in the mineral inclusions of primitive meteorites. (orig.)

  13. Cytopatholologic features of gliosarcoma with areas of primitive neuroepithelial differentiation of the brain in squash smears.

    Science.gov (United States)

    Hayashi, Toshitetsu; Kushida, Yoshio; Kadota, Kyuichi; Katsuki, Naomi; Bando, Kenji; Miyai, Yumi; Funamoto, Yasunobu; Haba, Reiji

    2009-12-01

    Gliosarcoma with areas of primitive neuroepithelial differentiation (GSPNED) is an extremely rare neoplasm. A case is presented here in which squash smears of a left temporal lobe tumor in a 76-year-old male demonstrated two distinct and easily recognizable cellular populations, i.e., densely hyperchromatic cells of a primitive nature in a fibrillary background and pleomorphic spindle-shaped cells. Occasional pseudo-rosette formations and nuclear cannibalism suggestive of neuroendocrine differentiation were also found. A cytologic diagnosis of a malignant tumor was suggested, and histochemical and immunohistochemical studies were conducted on formalin-fixed, paraffin-embedded material. Reticulin stain highlighted increased intercellular collagen and reticulin deposition within the spindled regions, whereas nodules with primitive cells were reticulin-poor. There was a diffuse and strong reactivity to neuron specific enolase, synaptophysin and CD56 immunostains. A stain for glial fibrillary acidic protein and S-100 protein demonstrated a subset of tumor cells including elongated cytoplasmic processes. The spindled component was positive for vimentin and smooth muscle actin, whereas the primitive-appearing tumor cells were negative. The diagnosis of GSPNED was confirmed based on cytopathologic, histopathological and immunohistochemical results. The cytomorphologic features of this distinctive tumor are illustrated, and the adjunctival value of squash smears for frozen-section diagnosis is also discussed. This is the first presentation of a cytopathologic analysis that provides an important clue to an accurate diagnosis of GSPNED.

  14. Non-enzymatic glycolysis and pentose phosphate pathway-like reactions in a plausible Archean ocean.

    Science.gov (United States)

    Keller, Markus A; Turchyn, Alexandra V; Ralser, Markus

    2014-04-25

    The reaction sequences of central metabolism, glycolysis and the pentose phosphate pathway provide essential precursors for nucleic acids, amino acids and lipids. However, their evolutionary origins are not yet understood. Here, we provide evidence that their structure could have been fundamentally shaped by the general chemical environments in earth's earliest oceans. We reconstructed potential scenarios for oceans of the prebiotic Archean based on the composition of early sediments. We report that the resultant reaction milieu catalyses the interconversion of metabolites that in modern organisms constitute glycolysis and the pentose phosphate pathway. The 29 observed reactions include the formation and/or interconversion of glucose, pyruvate, the nucleic acid precursor ribose-5-phosphate and the amino acid precursor erythrose-4-phosphate, antedating reactions sequences similar to that used by the metabolic pathways. Moreover, the Archean ocean mimetic increased the stability of the phosphorylated intermediates and accelerated the rate of intermediate reactions and pyruvate production. The catalytic capacity of the reconstructed ocean milieu was attributable to its metal content. The reactions were particularly sensitive to ferrous iron Fe(II), which is understood to have had high concentrations in the Archean oceans. These observations reveal that reaction sequences that constitute central carbon metabolism could have been constrained by the iron-rich oceanic environment of the early Archean. The origin of metabolism could thus date back to the prebiotic world.

  15. Sex ratio meiotic drive as a plausible evolutionary mechanism for hybrid male sterility.

    Directory of Open Access Journals (Sweden)

    Linbin Zhang

    2015-03-01

    Full Text Available Biological diversity on Earth depends on the multiplication of species or speciation, which is the evolution of reproductive isolation such as hybrid sterility between two new species. An unsolved puzzle is the exact mechanism(s that causes two genomes to diverge from their common ancestor so that some divergent genes no longer function properly in the hybrids. Here we report genetic analyses of divergent genes controlling male fertility and sex ratio in two very young fruitfly species, Drosophila albomicans and D. nasuta. A majority of the genetic divergence for both traits is mapped to the same regions by quantitative trait loci mappings. With introgressions, six major loci are found to contribute to both traits. This genetic colocalization implicates that genes for hybrid male sterility have evolved primarily for controlling sex ratio. We propose that genetic conflicts over sex ratio may operate as a perpetual dynamo for genome divergence. This particular evolutionary mechanism may largely contribute to the rapid evolution of hybrid male sterility and the disproportionate enrichment of its underlying genes on the X chromosome--two patterns widely observed across animals.

  16. Aluminum and Alzheimer's disease: after a century of controversy, is there a plausible link?

    Science.gov (United States)

    Tomljenovic, Lucija

    2011-01-01

    The brain is a highly compartmentalized organ exceptionally susceptible to accumulation of metabolic errors. Alzheimer's disease (AD) is the most prevalent neurodegenerative disease of the elderly and is characterized by regional specificity of neural aberrations associated with higher cognitive functions. Aluminum (Al) is the most abundant neurotoxic metal on earth, widely bioavailable to humans and repeatedly shown to accumulate in AD-susceptible neuronal foci. In spite of this, the role of Al in AD has been heavily disputed based on the following claims: 1) bioavailable Al cannot enter the brain in sufficient amounts to cause damage, 2) excess Al is efficiently excreted from the body, and 3) Al accumulation in neurons is a consequence rather than a cause of neuronal loss. Research, however, reveals that: 1) very small amounts of Al are needed to produce neurotoxicity and this criterion is satisfied through dietary Al intake, 2) Al sequesters different transport mechanisms to actively traverse brain barriers, 3) incremental acquisition of small amounts of Al over a lifetime favors its selective accumulation in brain tissues, and 4) since 1911, experimental evidence has repeatedly demonstrated that chronic Al intoxication reproduces neuropathological hallmarks of AD. Misconceptions about Al bioavailability may have misled scientists regarding the significance of Al in the pathogenesis of AD. The hypothesis that Al significantly contributes to AD is built upon very solid experimental evidence and should not be dismissed. Immediate steps should be taken to lessen human exposure to Al, which may be the single most aggravating and avoidable factor related to AD.

  17. Exploring plausible formation scenarios for the planet candidate orbiting Proxima Centauri

    CERN Document Server

    Coleman, Gavin A L; Paardekooper, Sijme-Jan; Dreizler, Stefan; Giesers, Benjamin; Anglada-Escude, Guillem

    2016-01-01

    We present a study of 4 different formation scenarios that may explain the origin of the recently announced planet `Proxima b' orbiting the star Proxima Centauri. The aim is to examine how the formation scenarios differ in their predictions for the multiplicity of the Proxima planetary system, the water/volatile content of Proxima b and its eccentricity, so that these can be tested by future observations. A scenario of in situ formation via giant impacts from a locally enhanced disc of planetary embryos and planetesimals, predicts that Proxima b will be a member of a multiplanet system with a measurably finite value of orbital eccentricity. Assuming that the local solid enhancement needed to form a Proxima b analogue with a minimum mass of 1.3 Earth masses arises because of the inwards drift of solids in the form of small planetesimals/boulders, this scenario also likely results in Proxima b analogues that are moderately endowed with water/volatiles, arising from the dynamical diffusion of icy planetesimals f...

  18. Sex ratio meiotic drive as a plausible evolutionary mechanism for hybrid male sterility.

    Science.gov (United States)

    Zhang, Linbin; Sun, Tianai; Woldesellassie, Fitsum; Xiao, Hailian; Tao, Yun

    2015-03-01

    Biological diversity on Earth depends on the multiplication of species or speciation, which is the evolution of reproductive isolation such as hybrid sterility between two new species. An unsolved puzzle is the exact mechanism(s) that causes two genomes to diverge from their common ancestor so that some divergent genes no longer function properly in the hybrids. Here we report genetic analyses of divergent genes controlling male fertility and sex ratio in two very young fruitfly species, Drosophila albomicans and D. nasuta. A majority of the genetic divergence for both traits is mapped to the same regions by quantitative trait loci mappings. With introgressions, six major loci are found to contribute to both traits. This genetic colocalization implicates that genes for hybrid male sterility have evolved primarily for controlling sex ratio. We propose that genetic conflicts over sex ratio may operate as a perpetual dynamo for genome divergence. This particular evolutionary mechanism may largely contribute to the rapid evolution of hybrid male sterility and the disproportionate enrichment of its underlying genes on the X chromosome--two patterns widely observed across animals.

  19. The composition of mantle plumes and the deep Earth

    Science.gov (United States)

    Hastie, Alan R.; Fitton, J. Godfrey; Kerr, Andrew C.; McDonald, Iain; Schwindrofska, Antje; Hoernle, Kaj

    2016-06-01

    Determining the composition and geochemical diversity of Earth's deep mantle and subsequent ascending mantle plumes is vital so that we can better understand how the Earth's primitive mantle reservoirs initially formed and how they have evolved over the last 4.6 billion years. Further data on the composition of mantle plumes, which generate voluminous eruptions on the planet's surface, are also essential to fully understand the evolution of the Earth's hydrosphere and atmosphere with links to surface environmental changes that may have led to mass extinction events. Here we present new major and trace element and Sr-Nd-Pb-Hf isotope data on basalts from Curacao, part of the Caribbean large igneous province. From these and literature data, we calculate combined major and trace element compositions for the mantle plumes that generated the Caribbean and Ontong Java large igneous provinces and use mass balance to determine the composition of the Earth's lower mantle. Incompatible element and isotope results indicate that mantle plumes have broadly distinctive depleted and enriched compositions that, in addition to the numerous mantle reservoirs already proposed in the literature, represent large planetary-scale geochemical heterogeneity in the Earth's deep mantle that are similar to non-chondritic Bulk Silicate Earth compositions.

  20. Learned parametrized dynamic movement primitives with shared synergies for controlling robotic and musculoskeletal systems

    Directory of Open Access Journals (Sweden)

    Elmar eRückert

    2013-10-01

    Full Text Available A salient feature of human motor skill learning is the ability to exploitsimilarities across related tasks.In biological motor control, it has been hypothesized that muscle synergies,coherent activations of groups of muscles, allow for exploiting shared knowledge.Recent studies have shown that a rich set of complex motor skills can be generated bya combination of a small number of muscle synergies.In robotics, dynamic movement primitives are commonlyused for motor skill learning. This machine learning approach implements a stable attractor systemthat facilitates learning and it can be used in high-dimensional continuous spaces. However, it does not allow for reusing shared knowledge, i.e. for each task an individual set of parameters has to be learned.We propose a novel movement primitive representationthat employs parametrized basis functions, which combines the benefits of muscle synergiesand dynamic movement primitives. For each task asuperposition of synergies modulates a stable attractor system.This approach leads to a compact representation of multiple motor skills andat the same time enables efficient learning in high-dimensional continuous systems.The movement representation supports discrete and rhythmic movements andin particular includes the dynamic movement primitive approach as a special case.We demonstrate the feasibility of the movement representation in three multi-task learning simulated scenarios.First, the characteristics of the proposed representation are illustrated in a point-mass task.Second, in complex humanoid walking experiments,multiple walking patterns with different step heights are learned robustly and efficiently.Finally, in a multi-directional reaching task simulated with a musculoskeletal modelof the human arm, we show how the proposed movement primitives can be used tolearn appropriate muscle excitation patterns and to generalize effectively to new reaching skills.

  1. Effects of the reappearance of primitive reflexes on eating function and prognosis.

    Science.gov (United States)

    Hobo, Kimiko; Kawase, Junko; Tamura, Fumiyo; Groher, Michael; Kikutani, Takeshi; Sunakawa, Hajime

    2014-01-01

    Primitive reflexes can reappear with diseases of the brain, particularly those affecting the frontal lobes. Most studies on primitive reflexes have reported an association between such reflexes and brain damage, and the clinical symptoms of dementia. These reflexes can also be present during eating; however, their effects on eating function are difficult to evaluate. The purpose of the present study was to identify the frequency at which primitive reflexes reappear in elderly people, and to determine the effects that such reflexes have on eating function, nutritional status and prognosis. We followed 121 nursing home residents for 6 months. All patients required long-term care and were examined for the presence of a sucking reflex, snout reflex and phasic bite reflex for baseline measures. Demographic characteristics, physical and cognitive function, and nutritional status were obtained from chart reviews, interviews with nurses, and a brief physical examination at baseline and incidence of aspiration pneumonia during the study period. The sucking reflex was confirmed in 31 patients (25.6%), snout reflex in 15 patients (12.3%) and phasic bite reflex in 28 patients (23.1%). One or more of these reflexes was identified in 38 patients (31.4%). A relationship between the presence of a primitive reflex and nutritional status was shown. An association with the presence of these reflexes and the development of aspiration pneumonia during 6 months was also confirmed. The appearance of primitive reflexes appears to be associated with the risk of malnutrition and developing aspiration pneumonia. © 2013 Japan Geriatrics Society.

  2. Correct patterning of the primitive streak requires the anterior visceral endoderm.

    Directory of Open Access Journals (Sweden)

    Daniel W Stuckey

    Full Text Available Anterior-posterior axis specification in the mouse requires signalling from a specialised extra-embryonic tissue called the anterior visceral endoderm (AVE. AVE precursors are induced at the distal tip of the embryo and move to the prospective anterior. Embryological and genetic analysis has demonstrated that the AVE is required for anterior patterning and for correctly positioning the site of primitive streak formation by inhibiting Nodal activity. We have carried out a genetic ablation of the Hex-expressing cells of the AVE (Hex-AVE by knocking the Diphtheria toxin subunit A into the Hex locus in an inducible manner. Using this model we have identified that, in addition to its requirement in the anterior of the embryo, the Hex-AVE sub-population has a novel role between 5.5 and 6.5dpc in patterning the primitive streak. Embryos lacking the Hex-AVE display delayed initiation of primitive streak formation and miss-patterning of the anterior primitive streak. We demonstrate that in the absence of the Hex-AVE the restriction of Bmp2 expression to the proximal visceral endoderm is also defective and expression of Wnt3 and Nodal is not correctly restricted to the posterior epiblast. These results, coupled with the observation that reducing Nodal signalling in Hex-AVE ablated embryos increases the frequency of phenotypes observed, suggests that these primitive streak patterning defects are due to defective Nodal signalling. Together, our experiments demonstrate that the AVE is not only required for anterior patterning, but also that specific sub-populations of this tissue are required to pattern the posterior of the embryo.

  3. New hybrid voxelized/analytical primitive in Monte Carlo simulations for medical applications

    Science.gov (United States)

    Bert, Julien; Lemaréchal, Yannick; Visvikis, Dimitris

    2016-05-01

    Monte Carlo simulations (MCS) applied in particle physics play a key role in medical imaging and particle therapy. In such simulations, particles are transported through voxelized phantoms derived from predominantly patient CT images. However, such voxelized object representation limits the incorporation of fine elements, such as artificial implants from CAD modeling or anatomical and functional details extracted from other imaging modalities. In this work we propose a new hYbrid Voxelized/ANalytical primitive (YVAN) that combines both voxelized and analytical object descriptions within the same MCS, without the need to simultaneously run two parallel simulations, which is the current gold standard methodology. Given that YVAN is simply a new primitive object, it does not require any modifications on the underlying MC navigation code. The new proposed primitive was assessed through a first simple MCS. Results from the YVAN primitive were compared against an MCS using a pure analytical geometry and the layer mass geometry concept. A perfect agreement was found between these simulations, leading to the conclusion that the new hybrid primitive is able to accurately and efficiently handle phantoms defined by a mixture of voxelized and analytical objects. In addition, two application-based evaluation studies in coronary angiography and intra-operative radiotherapy showed that the use of YVAN was 6.5% and 12.2% faster than the layered mass geometry method, respectively, without any associated loss of accuracy. However, the simplification advantages and differences in computational time improvements obtained with YVAN depend on the relative proportion of the analytical and voxelized structures used in the simulation as well as the size and number of triangles used in the description of the analytical object meshes.

  4. New hybrid voxelized/analytical primitive in Monte Carlo simulations for medical applications.

    Science.gov (United States)

    Bert, Julien; Lemaréchal, Yannick; Visvikis, Dimitris

    2016-05-01

    Monte Carlo simulations (MCS) applied in particle physics play a key role in medical imaging and particle therapy. In such simulations, particles are transported through voxelized phantoms derived from predominantly patient CT images. However, such voxelized object representation limits the incorporation of fine elements, such as artificial implants from CAD modeling or anatomical and functional details extracted from other imaging modalities. In this work we propose a new hYbrid Voxelized/ANalytical primitive (YVAN) that combines both voxelized and analytical object descriptions within the same MCS, without the need to simultaneously run two parallel simulations, which is the current gold standard methodology. Given that YVAN is simply a new primitive object, it does not require any modifications on the underlying MC navigation code. The new proposed primitive was assessed through a first simple MCS. Results from the YVAN primitive were compared against an MCS using a pure analytical geometry and the layer mass geometry concept. A perfect agreement was found between these simulations, leading to the conclusion that the new hybrid primitive is able to accurately and efficiently handle phantoms defined by a mixture of voxelized and analytical objects. In addition, two application-based evaluation studies in coronary angiography and intra-operative radiotherapy showed that the use of YVAN was 6.5% and 12.2% faster than the layered mass geometry method, respectively, without any associated loss of accuracy. However, the simplification advantages and differences in computational time improvements obtained with YVAN depend on the relative proportion of the analytical and voxelized structures used in the simulation as well as the size and number of triangles used in the description of the analytical object meshes.

  5. Pangea B: a plausible impossibility is always preferable to an uncommitting possibility (Aristotle, Poetics 7)

    Science.gov (United States)

    Muttoni, G.; Kent, D. V.; Garzanti, E.; Brack, P.; Abrahamsen, N.; Gaetani, M.

    2003-04-01

    The Wegenerian configuration of Pangea at Jurassic times is not questioned among Earth scientists. Debate exists on its pre-Jurassic configuration since Ted Irving in 1977 introduced Pangea 'B' by placing Gondwana to the East by ≈3000km with respect to Laurasia on the basis of paleomagnetic data. Pangea 'B' and its tectonic implications have not been however broadly accepted by the scientific community. We review data from Gondwana and Laurasia strictly from igneous rocks, and conclude that Pangea 'B' is indeed paleomagnetically acceptable in the Early Permian. Importantly, the exclusive use of paleomagnetic data from igneous rocks virtually excludes possible effects of sedimentary inclination error as an explanation for Pangea 'B' as envisaged by Rochette and Vandamme (1998). The ultimate option to reject Pangea 'B' is to abandon the geocentral axial dipole (GAD) hypothesis by introducing a specific octupole component of a specific amount with a specific sign in the Late Paleozoic time-averaged geomagnetic field (Van der Voo and Torsvik, 2001). We demonstrate, however, by using a dataset made exclusively and entirely of paleomagnetic directions with low inclinations from the northern hemisphere, that the effects of an octupole field contamination can not account for Pangea 'B' in the Early Permian. We therefore review geological data from the literature in support of Pangea dextral mega-shear. The transformation from Pangea 'B' to Pangea 'A' occurred after the cooling of the Varisican lithosphere during the Permian at a minimum plate speed of ≈15cm/yr. No Triassic transformation is herein envisaged. The transformation is coeval with the opening of the Neotethys Ocean, which took place along the eastern margin of Gondwanan between India/Arabia and the Cimmerian continents, and widespread lithospheric wrenching and magmatism in the west, along the margin of the Adriatic promontory. We show that the "push-pull" driving forces associated with the Gondwana grand

  6. The Lifeworld Earth and a Modelled Earth

    Science.gov (United States)

    Juuti, Kalle

    2014-01-01

    The goal of this paper is to study the question of whether a phenomenological view of the Earth could be empirically endorsed. The phenomenological way of thinking considers the Earth as a material entity, but not as an object as viewed in science. In the learning science tradition, tracking the process of the conceptual change of the shape of the…

  7. The Lifeworld Earth and a Modelled Earth

    Science.gov (United States)

    Juuti, Kalle

    2014-01-01

    The goal of this paper is to study the question of whether a phenomenological view of the Earth could be empirically endorsed. The phenomenological way of thinking considers the Earth as a material entity, but not as an object as viewed in science. In the learning science tradition, tracking the process of the conceptual change of the shape of the…

  8. Primitive trigeminal artery-cavernous sinus fistula and ICA-primitive trigeminal artery aneurysm:report of two cases and review of literatures

    Institute of Scientific and Technical Information of China (English)

    GUO Yuan-xing; LI Tie-lin; DUAN Chuan-zhi; WANG Qiu-jing; HUANG Qing

    2004-01-01

    The authors described two cases with primitive trigeminal artery. Case 1 was a 32-year-old woman who suffered dizziness and a serious pulsatile intracranial bruit on the left ear, and sometimes associated with pulsatile intracranial bearing-pain on the left temporal side six months before she was admitted to the hospital. She also suffered from obvious diplopia on left lateral gaze for the last 5 months. She had suffered no recent trauma. Magnetic resonance imaging(MRI) demonstrated a suspected intracranial aneurysm located in left cavernous sinus. Digital subtraction angiography (DSA) was performed and a primitive trigeminal artery-cavernous sinus fistula in left side was found. Intraluminal occlusion of the fistula was successfully performed immediately after angiography using 6 Guglielmi detachable coils (GDC), and the patient was cured finally. Case 2 was a 28-year-old woman who suffered a serious intermittent cephalodynia associated with soreness on the left body two years before she was admitted to the hospital. She had suffered no recent trauma. Magnetic resonance angiography(MRA) demonstrated a suspected intracavernous aneurysm of the right internal carotid artery, Digital subtraction angiography (DSA) was performed. Right internal carotid angiography showed a primitive trigeminal artery (PTA) run between the cavernous segment of the internal carotid artery and the distal portion of the basilar artery. On initiation of PTA of R-ICA a small wide-necked saccular aneurysm was incidentally visualized. The aneurysm was successfully embolized after angiography using 2 Stent (Neuroform, 4.5mmm × 20mmm)-assisted detachable coils (Matrix), the ICA and PTA were preserved, and the patient was cured finally.

  9. A Note on Unified Statistics Including Fermi-Dirac, Bose-Einstein, and Tsallis Statistics, and Plausible Extension to Anisotropic Effect

    Directory of Open Access Journals (Sweden)

    Christianto V.

    2007-04-01

    Full Text Available In the light of some recent hypotheses suggesting plausible unification of thermostatistics where Fermi-Dirac, Bose-Einstein and Tsallis statistics become its special subsets, we consider further plausible extension to include non-integer Hausdorff dimension, which becomes realization of fractal entropy concept. In the subsequent section, we also discuss plausible extension of this unified statistics to include anisotropic effect by using quaternion oscillator, which may be observed in the context of Cosmic Microwave Background Radiation. Further observation is of course recommended in order to refute or verify this proposition.

  10. EarthKAM

    Data.gov (United States)

    National Aeronautics and Space Administration — Sponsored by NASA, EarthKAM (Earth Knowledge Acquired by Middle School Students) is an educational outreach program allowing middle school students to take pictures...

  11. Earth on the Move.

    Science.gov (United States)

    Naturescope, 1987

    1987-01-01

    Provides background information on the layers of the earth, the relationship between changes on the surface of the earth and its insides, and plate tectonics. Teaching activities are included, with some containing reproducible worksheets and handouts to accompany them. (TW)

  12. NASA Earth Exchange (NEX)

    Data.gov (United States)

    National Aeronautics and Space Administration — The NASA Earth Exchange (NEX) represents a new platform for the Earth science community that provides a mechanism for scientific collaboration and knowledge sharing....

  13. Ionic liquid pretreatment of biomass for sugars production: Driving factors with a plausible mechanism for higher enzymatic digestibility.

    Science.gov (United States)

    Raj, Tirath; Gaur, Ruchi; Dixit, Pooja; Gupta, Ravi P; Kagdiyal, V; Kumar, Ravindra; Tuli, Deepak K

    2016-09-20

    In this study, five ionic liquids (ILs) have been explored for biomass pretreatment for the production of fermentable sugar. We also investigated the driving factors responsible for improved enzymatic digestibility of various ILs treated biomass along with postulating the plausible mechanism thereof. Post pretreatment, mainly two factors impacted the enzymatic digestibility (i) structural deformation (cellulose I to II) along with xylan/lignin removal and (ii) properties of ILs; wherein, K-T parameters, viscosity and surface tension had a direct influence on pretreatment. A systematic investigation of these parameters and their impact on enzymatic digestibility is drawn. [C2mim][OAc] with β-value 1.32 resulted 97.7% of glucose yield using 10 FPU/g of biomass. A closer insight into the cellulose structural transformation has prompted a plausible mechanism explaining the better digestibility. The impact of these parameters on the digestibility can pave the way to customize the process to make biomass vulnerable to enzymatic attack.

  14. Antimicrobial drug use in Austrian pig farms: plausibility check of electronic on-farm records and estimation of consumption.

    Science.gov (United States)

    Trauffler, M; Griesbacher, A; Fuchs, K; Köfer, J

    2014-10-25

    Electronic drug application records from farmers from 75 conventional pig farms were revised and checked for their plausibility. The registered drug amounts were verified by comparing the farmers' records with veterinarians' dispensary records. The antimicrobial consumption was evaluated from 2008 to 2011 and expressed in weight of active substance(s), number of used daily doses (nUDD), number of animal daily doses (nADD) and number of product-related daily doses (nPrDD). All results were referred to one year and animal bodyweight (kg biomass). The data plausibility proof revealed about 14 per cent of unrealistic drug amount entries in the farmers' records. The annual antimicrobial consumption was 33.9 mg/kg/year, 4.9 UDDkg/kg/year, 1.9 ADDkg/kg/year and 2.5 PrDDkg/kg/year (average). Most of the antimicrobials were applied orally (86 per cent) and at group-level. Main therapy indications were metaphylactic/prophylactic measures (farrow-to-finish and fattening farms) or digestive tract diseases (breeding farms). The proportion of the 'highest priority critically important antimicrobials' was low (12 per cent). After determination of a threshold value, farms with a high antimicrobial use could be detected. Statistical tests showed that the veterinarian had an influence on the dosage, the therapy indication and the active substance. Orally administered antimicrobials were mostly underdosed, parenterally administered antimicrobials rather correctly or overdosed.

  15. Melting and Mixing States of the Earth's Mantle after the Moon-Forming Impact

    CERN Document Server

    Nakajima, Miki

    2015-01-01

    The Earth's Moon is thought to have formed by an impact between the Earth and an impactor around 4.5 billion years ago. This impact could have been so energetic that it could have mixed and homogenized the Earth's mantle. However, this view appears to be inconsistent with geochemical studies that suggest that the Earth's mantle was not mixed by the impact. Another plausible outcome is that this energetic impact melted the whole mantle, but the extent of mantle melting is not well understood even though it must have had a significant effect on the subsequent evolution of the Earth's interior and atmosphere. To understand the initial state of the Earth's mantle, we perform giant impact simulations using smoothed particle hydrodynamics (SPH) for three different models: (a) standard: a Mars-sized impactor hits the proto-Earth, (b) fast-spinning Earth: a small impactor hits a rapidly rotating proto-Earth, and (c) sub-Earths: two half Earth-sized planets collide. We use two types of equations of state (MgSiO3 liqui...

  16. The habitability of super-Earths in Gliese 581

    CERN Document Server

    Von Bloh, W; Cuntz, M; Franck, S

    2007-01-01

    Aims: The planetary system around the M star Gliese 581 consists of a hot Neptune (Gl 581b) and two super-Earths (Gl 581c and Gl 581d). The habitability of this system with respect to the super-Earths is investigated following a concept that studies the long-term possibility of photosynthetic biomass production on a dynamically active planet. Methods: A thermal evolution model for a super-Earth is used to calculate the sources and sinks of atmospheric carbon dioxide. The habitable zone is determined by the limits of biological productivity on the planetary surface. Models with different ratios of land / ocean coverage are investigated. Results: The super-Earth Gl 581c is clearly outside the habitable zone, since it is too close to the star. In contrast, Gl 581d is a tidally locked habitable super-Earth near the outer edge of the habitable zone. Despite the adverse conditions on this planet, at least some primitive forms of life may be able to exist on its surface.

  17. [The cultural history of palliative care in primitive societies: an integrative review].

    Science.gov (United States)

    Siles González, José; Solano Ruiz, Maria Del Carmen

    2012-08-01

    The objective of this study is to describe the evolution of palliative care in order to reflect on the possibility of its origin in primitive cultures and their relationship with the beginnings of the cult of the dead. It describes the change in the symbolic structures and social interactions involved in palliative care during prehistory: functional unit, functional framework and functional element. The theoretical framework is based on cultural history, the dialectical structural model and symbolic interactionism. Categorization techniques, cultural history and dialectic structuralism analyses were performed. Palliative care existed in primitive societies, mostly associated with the rites of passage with a high symbolic content. The social structures - functional unit, functional framework and functional element - are the pillars that supported palliative care in prehistory societies.

  18. Histological observation of some primitive euconodonts of Late Cambrian from Liaoning

    Institute of Scientific and Technical Information of China (English)

    GUO Wei; DONG Xiping; ZENG Xiaochun; ZHAO Le

    2005-01-01

    The histology of some euconodonts of Late Cambrian from Benxi and Fuxian County, Liaoning Province is studied by the oil-immersion technique. The histological characteristics of six primitive species of euconodonts - Proconodontus muelleri, Proconodontus tenuiserratus, Granatodontus ani, Rotundoconus tricarinatus, Teridontus nakamurai and Cordylodus proavus are describedin detail. Tubular dentine and atubular (parallel- and wavy-lamellar) dentine are found in the basal bodies of the primitive euconodonts Proconodontus tenuiserratus and Proconodontus muelleri, respectively. The tubular dentine and spherulitic dentine are also recognized from the basal bodies of Granatodontus ani and Rotundoconus tricarinatus. Since the histological characteristics of the studied six species of euconodonts belonging to Proconodontus lineage and Teridontus lineage Sensu Miller (Univ Kansas Paleontol Contr, 1980, 99: 1-39)seems to be almost the same, euconodonts are proposed as possibly monophyletic herein.

  19. Orthogonality of the idempotent elements with rank one in primitive rings

    Institute of Scientific and Technical Information of China (English)

    蒋滋梅

    1996-01-01

    Let R be a primitive ring with nonzero socle, M a faithful irreducible right R-module, A the central-izer of M, and L= a direct sum of countably many minimal right ideals L, of R. Then there existsa family of subsetsis infinite) of R such that L=R for any W, whereeach is a set of countably many orthogonal idempotent elements of rank one in R. Furthermore,there exists a primitive ring R and a direct sum L=of countably many minimal right ideals Li ofR, but R has no subset B =of countably many orthogonal idempotent elements of rank one such that and B can be extended to a corresponding basis of some basis of M over A.

  20. Computing the Intersection of a Plane and Geometric Primitives in VRML Model for Rapid Prototyping Software

    Institute of Scientific and Technical Information of China (English)

    LI Zhanli; SUN Xiuying

    2006-01-01

    VRML(Virtual Reality Modeling Language) format as an international standard for virtual reality, has already been widely adopted for graphical representation of 3D objects over the Web. Adopting VRML model in RP(Rapid Prototyping) can reduce the precision loss which is caused by triangulation in generating STL file. Hence exploring a slicing method and developing a slicing software for VRML model is important and significant to improve the accuracy of RP products. Finding intersections of a plane and VRML model is the key operation in slicing algorithm. This paper presents a method for calculating the intersections between a set of parallel planes and VRML geometric primitives. Based on the analysis of the relative position between a plane and a geometric primitive, intersection conditions in all cases were obtained, and the geometric parameters and corresponding equations of intersections were derived. The algorithm had been tested, and applications show that it is robust and effective.

  1. Peripheral primitive neuroectodermal tumor in a two-year-old paint horse.

    Science.gov (United States)

    Facemire, Paul R; Facemire, Lynn M; Honnold, Shelley P

    2012-07-01

    A 2-year-old gelding presented with a history of lethargy and anorexia. Physical examination revealed pleural and abdominal fluid, as well as several masses in the scrotum. The horse became acutely dyspneic despite 7 days of supportive care. Because of the poor prognosis, the owners elected euthanasia. Gross necropsy findings included multiple masses in the scrotum and inguinal canals and along the dorsal peritoneal cavity. The neoplasm infiltrated the kidneys, liver, spleen, mesenteric lymph nodes, mesentery, and abdominal surface of the diaphragm. Histologically, the neoplasm is composed of spindle to round cells arranged in densely cellular areas, vague streams, and rare rosettes. Neoplastic cells were immunoreactive for S-100 protein, glial fibrillary acidic protein, neuron-specific enolase, neurofilament protein, and synaptophysin. Based on gross, histological, and immunohistochemical findings, a diagnosis of peripheral primitive neuroectodermal tumor was made. Primitive neuroectodermal tumors are rarely described in horses that were associated with the eyes.

  2. Stochastic modelling of primitive equation and quasi-geostrophic subgrid turbulence

    Science.gov (United States)

    Frederiksen, Jorgen; Kitsios, Vassili; Dix, Martin; Osbrough, Stacey

    2016-04-01

    A general method for stochastic and deterministic modelling of subgrid scale turbulence is presented and applied to primitive equation and quasi-geostrophic models of atmospheric and oceanic flows. Dynamical and thermodynamical subgrid-scale parameterisations of eddy drain, net dissipation and stochastic backscatter are calculated for a multi-level primitive equation atmospheric general circulation model. The parameterisations have only moderate variability with height and a cusp behaviour with peaks near the largest retained wavenumber. They are compared with corresponding results for quasi-geostrophic models of the atmosphere and ocean for which the parameterisations are shown to satisfy scaling laws. Large-eddy simulations (LES) with the subgrid terms very closely reproduce the results of higher resolution direct numerical simulations. The method is shown to produce parameterisations and LES with similar skill for three-dimensional turbulence in boundary layer channel flow.

  3. Ovarian malignant mixed mullerian tumor with primitive neuroectodermal differentiation: case report with review of the literature.

    Science.gov (United States)

    Nasser, Haitham; Morris, Robert T; Fathallah, Lamia

    2011-03-15

    Ovarian malignant mixed mullarian tumor (OMMMT) is a rare and aggressive tumor of the female genital tract, occurring mainly in elderly women. Stage of disease is the most important predictor for survival with no prognostic effect, yet, of heterologous elements. Rare case reports described the peculiar presence of primitive neuroectodermal tissue among other heterologous elements in these tumors. Attractive designations, such as teratoid carcinosarcoma, were set by some authors to describe this subset of lesions, where it was considered a primary neuroectodermal tumor capable of multilineage differentiation. We here report a case of OMMMT in an elderly woman with focal primitive neuroectodermal differentiation as the sole heterologous element, and review the controversy on this topic in the literature.

  4. Successful penile reconstruction after multimodal therapy in patients with primitive neuroectodermal tumor originating from the penis.

    Science.gov (United States)

    Akino, Tomoshige; Shinohara, Nobuo; Hatanaka, Kanako; Kobayashi, Nozomi; Yamamoto, Yuhei; Nonomura, Katsuya

    2014-06-01

    We herein present an extremely rare case of primitive neuroectodermal tumor originating in the penis. A 16-year-old male adolescent presented with painful penile swelling. Pathological, immunohistochemical and cytogenetical examinations of the specimens obtained from total penectomy confirmed the diagnosis of primitive neuroectodermal tumor. After total penectomy, the patient received adjuvant chemotherapy with ifosfamide-based regimen for 48 weeks. As a series of therapies, the patient underwent penile reconstruction surgery after completing adjuvant chemotherapy. The patient has not shown any evidence of recurrence for the 7 years after penile reconstruction surgery, and voiding function is completely normal. A favorable outcome was observed by multimodal therapy including aggressive resection for local control, intensive adjuvant chemotherapy, and penile reconstruction with cosmetic and functional success. Similar therapeutic approaches might be selected for children with primary malignant tumors of the penis.

  5. Ewing Sarcoma/Primitive Neuroectodermal Tumor of the Kidney: A Rare and Lethal Entity.

    Science.gov (United States)

    Celli, Romulo; Cai, Guoping

    2016-03-01

    Ewing sarcoma/primitive neuroectodermal tumor represents a spectrum of undifferentiated tumors with similar biology that together represent the second most common sarcoma in the pediatric-young adult age range. Very rarely, this tumor presents as a primary neoplasm of the kidney. The clinical presentation of this tumor is not specific, and other renal tumors may present with a similar histologic appearance. Establishing the correct diagnosis is critical because renal Ewing sarcoma/primitive neuroectodermal tumor carries a strikingly dismal prognosis and thus dictates a specific treatment strategy. A low threshold for the use of ancillary molecular tests is recommended, particularly in diagnostically problematic cases. Important considerations with regards to morphology, immunohistochemistry, and molecular alterations will be reviewed here and should be taken into account before rendering this rare and lethal diagnosis.

  6. Primitive neuroectodermal tumor of the sternum in a child: resection and reconstruction.

    Science.gov (United States)

    Sunil, Indira; Bond, Sheldon J; Nagaraj, Hirikati S

    2006-11-01

    Pediatric primary malignancies of the sternum are rare. They represent less than 1% of all bone tumors. Primitive neuroectodermal tumor of the chest wall or Askin's tumor is more often seen in the ribs than in the sternum. Surgical treatment involves resection of the tumor followed by primary reconstruction. We report the case of a 16-year-old adolescent boy who was diagnosed to have primitive neuroectodermal tumor of the sternum and underwent resection with primary reconstruction of the anterior chest wall. We describe for the first time the use of a 2-mm Gore-Tex Dualmesh plus biomaterial (W.L. Gore and Associates, Flagstaff, Ariz) and locking mandibular multiperforated titanium plates with screws (Stryker-Leibinger, Freiburg, Germany) for primary sternal reconstruction in a child. Despite having a wide resection, he did not require postoperative ventilation and had an uncomplicated recovery. The reconstructed chest wall has a normal contour with normal pulmonary physiology.

  7. On the Primitive Elements of Appointed Trace%指定迹的本原元素

    Institute of Scientific and Technical Information of China (English)

    王培培

    2012-01-01

    In this paper, we discuss the existence of the primitive elements of appointed trace over finite field. Based on exponents and estimation, we conclude that, when q ≥2, n ≥29 ,ξ∈GF(qn) can prove that ξ + ξ- 1 is a primitive element, meanwhile, Tr ( ξ ) = a, Tr ( ξ- 1 ) = b exists for any pair of prescribed element a,b∈Fqn.%讨论有限域上指定迹的本原元的存在性,利用指数和估计的方法得出相应的结论:当q≥2,n≥29时,存在ξ∈GF(qn)满足ξ+ξ-1是本原元素,同时对任意指定的元素a,b∈Fqn,有Tr(ξ)=a,Tr(ξ-1)=b.

  8. Primitive and contaminated basalts from the Southern Rocky Mountains, U.S.A

    Science.gov (United States)

    Doe, B.R.; Lipman, P.W.; Hedge, C.E.; Kurasawa, H.

    1969-01-01

    Basalts in the Southern Rocky Mountains province have been analyzed to determine if any of them are primitive. Alkali plagioclase xenocrysts armored with calcic plagioclase seem to be the best petrographic indicator of contamination. The next best indicator of contamination is quartz xenocrysts armored with clinopyroxene. On the rocks and the region studied, K2O apparently is the only major element with promise of separating primitive basalt from contaminated basalt inasmuch as it constitutes more than 1 % in all the obviously contaminated basalts. K2O: lead (> 4 ppm) and thorium (> 2 ppm) contents and Rb/Sr (> 0.035) are the most indicative of the trace elements studied. Using these criteria, three basalt samples are primitive (although one contains 1.7% K2O) and are similar in traceelement contents to Hawaiian and Eastern Honshu, Japan, primitive basalts. Contamination causes lead isotope ratios, 206Pb/204Pb and 208Pb/204Pb, to become less radiogenic, but it has little or no effect on 87Sr/86Sr. We interpret the effect on lead isotopes to be due to assimilation either of lower crustal granitic rocks, which contain 5-10 times as much lead as basalt and which have been low in U/Pb and Th/Pb since Precambrian times, or of upper crustal Precambrian or Paleozoic rocks, which have lost much of their radiogenic lead because of heating prior to assimilation. The lack of definite effects on strontium isotopes may be due to the lesser strontium contents of granitic crustal rocks relative to basaltic rocks coupled with lack of a large radiogenic enrichment in the crustal rocks. Lead isotope ratios were found to be less radiogenic in plagioclase separates from an obviously contaminated basalt than in the primitive basalts. The feldspar separate that is rich in sodic plagioclase xenocrysts was found to be similar to the whole-rock composition for 206Pb/204Pb and 208Pb/204Pb whereas a more dense fraction probably enriched in more calcic plagioclase phenocrysts is more similar

  9. The Primitive Edge of Creativity: Destruction and Reparation in Louise Bourgeois's Art.

    Science.gov (United States)

    Schiller, Britt-Marie

    2017-04-01

    Viewed within the psychic geography of Thomas Ogden's modes of generating and organizing experience, in particular the autistic-contiguous mode, Louise Bourgeois's creative imagination can be seen as originating on what Ogden (1989) has called the primitive edge of experience. This mode, dominated by the sensory, is characterized by chaos, fragmentation, and a loss of boundaries. In dynamic movements between the depressive and the autistic-contiguous positions, between destructive and reparative impulses, Bourgeois transforms experiences of chaos, as well as destructive aggression, into aesthetic order and form, into works of art. She is able to delve into the most elemental and presymbolic modes of psychic experience and artistically harness raw feelings and sensations on what can be called the primitive edge of creativity.

  10. John Wesley’s medical guide Primitive Physick from 1747: science, charlatanism or social medicine?

    Directory of Open Access Journals (Sweden)

    Helmut Renders

    2011-05-01

    Full Text Available In 1747, John Wesley, spiritus rector of the Methodist movement, published the first edition of his medical guide Primitive Physic[k]. What was its purpose in a world where the Royal Academy, herbalists, healers / as, exorcists and quacks competed for the attention of the population? What is its legacy and limitation, considering the different interests of contemporary religious movements in Brazil? The article introduces the different groups who promoted or pretended to promote health in 18th century England and compares the contents of the guide Primitive Physic [k] with their proposals and therapeutic strategies. The conclusion is that a significant portion of the guide consists of guidelines of the Royal Academy of Medicine, but that it always favors homemade remedies with ingredients available to humbler classes. In relation to the socalled Spiritual Physick, prayer is mentioned as a complementary measure, but the practice of exorcism is totally ignored.

  11. Listening to Quackery: Reading John Wesley's Primitive Physic in an Age of Health Care Reform.

    Science.gov (United States)

    Skinner, Daniel; Schneider, Adam

    2016-11-25

    This article uses a reading of John Wesley's Primitive Physic, or An Easy and Natural Method of Curing Most Diseases (1747) to resist the common rejection-often as "quackery"-of Wesley's treatments for common maladies. We engage Wesley not because he was right but because his approach offers useful moments of pause in light of contemporary medical epistemology. Wesley's recommendations were primarily oriented towards the categories of personal responsibility and capability, but he also sought to empower individuals-especially the poor-with the knowledge to safely and affordably treat maladies of their own. We leverage Primitive Physic to rethink contemporary medical knowledge production, especially as sanctioned by randomized clinical trials and legitimate views of experience and contemporary institutions such as the AMA. Ultimately, we suggest that the medical humanities has a key role to play in mining the discarded and dismissed for what they can tell scholars about medical knowledge.

  12. Capturing Near Earth Objects

    OpenAIRE

    Baoyin, Hexi; CHEN Yang; Li, Junfeng

    2011-01-01

    Recently, Near Earth Objects (NEOs) have been attracting great attention, and thousands of NEOs have been found to date. This paper examines the NEOs' orbital dynamics using the framework of an accurate solar system model and a Sun-Earth-NEO three-body system when the NEOs are close to Earth to search for NEOs with low-energy orbits. It is possible for such an NEO to be temporarily captured by Earth; its orbit would thereby be changed and it would become an Earth-orbiting object after a small...

  13. Number of primitive elements of field extension GF(pnm)/GF(pn)

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Presents the counting of the counts number of primitive elementsof finite dimensional field extension GF(pnm)/GF(pn) using (1) the principle of inclusion-exclusion, (2) the Möbius inversion, (3) the Euler Ø function, and the new identity obtained where, m>1, p is a prime, Ø(.) is Euler function, and q1,…,qk are the all distinct prime divisors of m.

  14. Primitive myxoid mesenchymal tumor of infancy: a report of a further case with locally aggressive behavior.

    LENUS (Irish Health Repository)

    Mulligan, Linda

    2012-02-01

    We report a case of an 8-month-old child with a primitive myxoid mesenchymal tumor of infancy arising in the thenar eminence. The lesion recurred after conservative excision and was ultimately nonresponsive to chemotherapy, necessitating partial amputation. The patient remains free of disease 5 years after this radical surgery. This is the 1st report of such a tumor since it was initially described by Alaggio and colleagues in 2006. The pathologic differential diagnosis is discussed.

  15. Primitive myxoid mesenchymal tumor of infancy: a report of a further case with locally aggressive behavior.

    LENUS (Irish Health Repository)

    Mulligan, Linda

    2011-01-01

    We report a case of an 8-month-old child with a primitive myxoid mesenchymal tumor of infancy arising in the thenar eminence. The lesion recurred after conservative excision and was ultimately nonresponsive to chemotherapy, necessitating partial amputation. The patient remains free of disease 5 years after this radical surgery. This is the 1st report of such a tumor since it was initially described by Alaggio and colleagues in 2006. The pathologic differential diagnosis is discussed.

  16. Anomalously large capacitance of an ionic liquid described by the restricted primitive model

    CERN Document Server

    Loth, M S; Shklovskii, B I

    2010-01-01

    We use Monte Carlo simulations to examine the simplest model of an ionic liquid, called the restricted primitive model, at a metal surface. We find that at moderately low temperatures the capacitance of the metal/ionic liquid interface is so large that the effective thickness of the electrostatic double-layer is smaller than the ion radius. We suggest a semi-quantitative theory to describe these results.

  17. Complete structure and organization of immunoglobulin heavy chain constant region genes in a phylogenetically primitive vertebrate.

    OpenAIRE

    Kokubu, F; Hinds, K.; Litman, R.; Shamblott, M J; Litman, G. W.

    1988-01-01

    Immunoglobulin (Ig) gene organization in Heterodontus francisci (horned shark), a phylogenetically primitive vertebrate, is unique. Homologous Ig heavy chain variable (VH) and constant region (CH) specific probes were used to screen a spleen cDNA library constructed in lambda gt11. Both secretory (SEC) and transmembrane (TM) cDNA clones were recovered; the latter were identified by a negative selection strategy. The complete sequence of the CH portion of a Heterodontus genomic DNA-lambda clon...

  18. Cis-cotranscription of two beta globin genes during chicken primitive hematopoiesis.

    Directory of Open Access Journals (Sweden)

    Hiroki Nagai

    Full Text Available Chicken beta globin locus contains four genes, two of which, rho and epsilon, are expressed from the earliest stage of primitive hematopoiesis. Here we show that the transcription of these two genes in the nucleus engages in "on/off" phases. During each "on" phase, cotranscription of rho and epsilon in cis is favored. We propose that these two chicken beta globin genes are transcribed not by competing for a transcription initiation complex, but in a cooperative way.

  19. Dispossessing Urbanization: Urban Marxism in the Face of the Problem of Primitive Accumulation

    OpenAIRE

    Piotr Juskowiak

    2015-01-01

    The article is a complex attempt to present the achievements of the broadly understood urban Marxism in the field of reinterpretation of the classic concept from the cards of Capital – “primitive accumulation”. Drawing on theories of such scholars as David Harvey (“accumulation by dispossession”) or Saskia Sassen (“expulsions”), the author points to the possible ways to operationalize the concept of “dispossessing urbanization”. Inspired by the theorizations of autonomist Marxists (Antonio Ne...

  20. Primary Epidural Peripheral Primitive Neuroectodermal Tumor of the Lumbar Spine: A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Woo Jung; Lee, Seung Hun; Joo, Kyung Bin [Dept. of Radiology, Hanyang University Hospital, Seoul (Korea, Republic of); Paik, Seung Sam; Jun, Young Jin [Dept. of Pathology, Hanyang University Hospital, Seoul (Korea, Republic of); Lee, Young Ho [Dept. of Pediatrics, Hanyang University Hospital, Seoul (Korea, Republic of)

    2011-05-15

    A primitive neuroectodermal tumor (PNET) is a highly malignant tumor in children and young adults, and extremely rare in the spine. We report a case of a primary epidural peripheral PNET of the lumbar spine. The present extremely rare case of primary epidural peripheral PNET of the lumbar spine illustrates the unexpected occurrence and should be included in differential diagnoses for patients with spinal tumors.