WorldWideScience

Sample records for agg dipsacaceae puzzle

  1. AGG Maailmameistrivõistluste eel

    Index Scriptorium Estoniae

    2008-01-01

    12.-14. juunini toimuvad Torontos Aesthetic Group Gymnastics (AGG) maailmameistrivõistlused Toronto Ülikooli võimlemiskeskuses. Nende võistluste korraldamise raske ülesande on võtnud oma õlule Kanada eestlaste võimlemisklubid Kalev Estienne ja Ritmika vastavalt Evelyn Koobi ja Annely Riga juhtimisel

  2. Diversification of CYCLOIDEA-like genes in Dipsacaceae (Dipsacales: implications for the evolution of capitulum inflorescences

    Directory of Open Access Journals (Sweden)

    Carlson Sara E

    2011-11-01

    Full Text Available Abstract Background CYCLOIDEA (CYC-like genes have been implicated in the development of capitulum inflorescences (i.e. flowering heads in Asteraceae, where many small flowers (florets are packed tightly into an inflorescence that resembles a single flower. Several rounds of duplication of CYC-like genes have occurred in Asteraceae, and this is hypothesized to be correlated with the evolution of the capitulum, which in turn has been implicated in the evolutionary success of the group. We investigated the evolution of CYC-like genes in Dipsacaceae (Dipsacales, a plant clade in which capitulum inflorescences originated independently of Asteraceae. Two main inflorescence types are present in Dipsacaceae: (1 radiate species contain two kinds of floret within the flowering head (disk and ray, and (2 discoid species contain only disk florets. To test whether a dynamic pattern of gene duplication, similar to that documented in Asteraceae, is present in Dipsacaceae, and whether these patterns are correlated with different inflorescence types, we inferred a CYC-like gene phylogeny for Dipsacaceae based on representative species from the major lineages. Results We recovered within Dipsacaceae the three major forms of CYC-like genes that have been found in most core eudicots, and identified several additional duplications within each of these clades. We found that the number of CYC-like genes in Dipsacaceae is similar to that reported for members of Asteraceae and that the same gene lineages (CYC1-like and CYC2B-like genes have duplicated in a similar fashion independently in both groups. The number of CYC-like genes recovered for radiate versus discoid species differed, with discoid species having fewer copies of CYC1-like and CYC2B-like genes. Conclusions CYC-like genes have undergone extensive duplication in Dipsacaceae, with radiate species having more copies than discoid species, suggesting a potential role for these genes in the evolution of disk and

  3. Puzzling Mechanisms

    Science.gov (United States)

    van Deventer, M. Oskar

    2009-01-01

    The basis of a good mechanical puzzle is often a puzzling mechanism. This article will introduce some new puzzling mechanisms, like two knots that engage like gears, a chain whose links can be interchanged, and flat gears that do not come apart. It illustrates how puzzling mechanisms can be transformed into real mechanical puzzles, e.g., by…

  4. Fiendishly puzzling

    Science.gov (United States)

    2016-12-01

    The UK's Government Communications Headquarters (GCHQ) has, over the last few years, published puzzles that keen members of the public could solve to get noticed by the organization's recruitment team. The GCHQ Puzzle Book is a chunky compendium whose readers are introduced to the whole back catalogue.

  5. 2008 CONEXPO-CON/AGG%镜头中的CONEXPO-CON/AGG2008

    Institute of Scientific and Technical Information of China (English)

    周贤彪

    2008-01-01

    @@ 于2008年3月11-15日在美国拉斯维加斯会展中心举行的CONEXPO-CON/AGG(建设机械展)和IFPE(动力传动展)圆满闭幕.CONEXPO-CON/AGG有2182家企业参展,展出净面积达21.2万平方米,较上届增长21%;IFPE有469家企业参展,展出净面积达1.2万平方米,较上届增长16%.14.46万人参观展会,其中国际观众2.8万人,占19%,中国、印度、土耳其的观众数量翻倍.

  6. Fragile X gene instability: Anchoring AGGs and linked microsatellites

    Energy Technology Data Exchange (ETDEWEB)

    Zhong, Nan; Yang, Weihong; Dobkin, C. [Institute for Basic Research in Developmental Disabilities, Staten Island, NY (United States)] [and others

    1995-08-01

    Interspersed AGGs within the FMR1 gene CGG repeat region may anchor the sequence and prevent slippage during replication. In order to detect the AGG position variations, we developed a method employing partial MnlI restriction analysis and analyzed X chromosomes from 187 males, including 133 normal controls (17 with 20-34 and 16 with 35-52 repeats), plus 54 fragile X premutations with 56-180 repeats. Among controls, the interspersed AGG positions were highly polymorphic, with heterozygosity of 91%. Among the control samples, 1.5% had no AGG positions, 25% had one, 71% had two, and 3% had three. Among the fragile X premutation samples, 63% had no AGG, while 37% had only one AGG. Analysis of premutation samples within fragile X families showed that variation occurred only within the 3{prime} end of the region. Thus, the instability was polar. Controls with {ge}15 pure CGG repeats were associated with the longest alleles of two nearby microsatellites, FRAXAC1 with 20-21 repeats and DXS548 with 202-206 bp and with increased microsatellite heterzygosity. The association of long pure CGG regions, as with fragile X chromosomes, with the longer and more heterozygous microsatellite alleles suggests they may be related mechanistically. Further, our results do not support a recent suggestion that the frequency of fragile X alleles may be increasing. Finally, analysis of a set of nonhuman primate samples showed that long pure CGG tracks are variable in size and are located within the 3{prime} region, which suggests that polar instability within FMR1 is evolutionarily quite old. 55 refs., 3 figs., 4 tabs.

  7. L’Allgemeine Gleichbehandlungsgesetz (AGG: Lex sum, nihil humani a me alienum puto

    Directory of Open Access Journals (Sweden)

    Stefano Testa Bappenheim

    2011-03-01

    Full Text Available SOMMARIO: 1. Introduzione – 2. Il contesto europeo maieuta delle «4 direttive» - 3. Le «4 direttive» - 4. L’ubi consistam costituzionale tedesco - 5. Le discriminazioni vietate – 6. Fenotipi laburistici dell’AGG - 7. Fenotipi civilistici dell’AGG – 8. Le discriminazioni ammesse - 9. Il § 9, extra Ecclesiis nulla exceptio.

  8. The role of AGG interruptions in fragile X repeat expansions: A twenty year perspective

    Directory of Open Access Journals (Sweden)

    Gary J. Latham

    2014-07-01

    Full Text Available In 1994 it was suggested that AGG interruptions affect the stability of the fragile X triplet repeat. Until recently, however, this hypothesis was not explored on a large scale due primarily to the technical difficulty of determining AGG interruption patterns of the two alleles in females. The recent development of a PCR technology that overcomes this difficulty and accurately identifies the number and position of AGGs has led to several studies that examine their influence on repeat stability. Here we present a historical perspective of relevant studies published during the last twenty years on AGG interruptions and examine those recent publications that have refined risk estimates for repeat instability and full mutation expansions.

  9. The Proton Radius Puzzle

    Directory of Open Access Journals (Sweden)

    Downie E. J.

    2016-01-01

    Full Text Available The proton radius puzzle is the difference between the proton radius as measured with electron scattering and in the excitation spectrum of atomic hydrogen, and that measured with muonic hydrogen spectroscopy. Since the inception of the proton radius puzzle in 2010 by the measurement of Pohl et al.[1], many possible resolutions to the puzzle have been postulated, but, to date, none has been generally accepted. New data are therefore necessary to resolve the issue. We briefly review the puzzle, the proposed solutions, and the new electron scattering and spectroscopy experiments planned and underway. We then introduce the MUSE experiment, which seeks to resolve the puzzle by simultaneously measuring elastic electron and muon scattering on the proton, in both charge states, thereby providing new information to the puzzle. MUSE addresses issues of two-photon effects, lepton universality and, possibly, new physics, while providing simultaneous form factor, and therefore radius, measurements with both muons and electrons.

  10. Tangrams: Puzzles of Art

    Science.gov (United States)

    Fee, Brenda

    2009-01-01

    Challenging one's brain is the beginning of making great art. Tangrams are a great way to keep students thinking about their latest art project long after leaving the classroom. A tangram is a Chinese puzzle. The earliest known reference to tangrams appears in a Chinese book dated 1813, but the puzzles existed long before that date. The puzzle…

  11. A puzzle for philosophers

    Directory of Open Access Journals (Sweden)

    Nicolás Lo Guercio

    2013-12-01

    Full Text Available In the paper I tackle a puzzle by Goldberg (2009 that challenges all of us as philosophers. There are three plausible thesis, separately defensible, that together seem to lead to a contradiction: 1 Reliability is a necessary condition for epistemic justification. 2 On contested matters in philosophy, philosophers are not reliable. 3 At least some philosophical theses regarding contested matters in philosophy are epistemically justified. In this paper I will assess the status of the puzzle and attempt to solve it. In the first section, I'll present the puzzle with a little more detail. Secondly, I'll provide some general arguments to show that the alleged puzzle is not a legitimate one. Finally, in section 3, I will argue that even assuming that the puzzle can be coherently formulated, Goldberg's arguments in favor of premise (2 are either unsound or too limited in their scope in order to represent a significant or interesting problem for philosophers.

  12. The AGG codon is translated slowly in E. coli even at very low expression levels

    DEFF Research Database (Denmark)

    Bonekamp, Fons; Jensen, Kaj Frank

    1988-01-01

    Data are presented which indicate that AGG codons for arginine are translated significantly more slowly than the CGU codons for the same amino acid even when their expression level from the probe is very low. The two types of codons were inser ted (three in tandem) on a multicopy plasmid in an ar...

  13. Games, puzzles, and computation

    CERN Document Server

    Hearn, Robert A

    2009-01-01

    The authors show that there are underlying mathematical reasons for why games and puzzles are challenging (and perhaps why they are so much fun). They also show that games and puzzles can serve as powerful models of computation-quite different from the usual models of automata and circuits-offering a new way of thinking about computation. The appendices provide a substantial survey of all known results in the field of game complexity, serving as a reference guide for readers interested in the computational complexity of particular games, or interested in open problems about such complexities.

  14. The Radicalization Puzzle [video

    OpenAIRE

    Mohammed Hafez; Center for Homeland Defense and Security Naval Postgraduate School

    2015-01-01

    This 20 minute lecture, by Dr. Mohammad Hafez of the Naval Postgraduate School examines the driving factors behind the process of radicalization, turning seemingly ordinary men and women into potential terrorists. The lecture is based on the article "The Radicalization Puzzle: A Theoretical Synthesis of Empirical Approaches to Homegrown Extremism" in Studies in Conflict and Terrorism, by Mohammad Hafez and Creighton Mullins.

  15. 透过CONEXPO-CON/AGG 2008看行业发展八大现象

    Institute of Scientific and Technical Information of China (English)

    李坤龙

    2008-01-01

    @@ 正值北美经济出现下滑之时,CONEXPO-CON/AGG 2008是否依然会光芒四射一度为众多业内人士所担心.但是亲临现场才知道CONEXPO-CON/AGG2008就如同一杯香浓的咖啡,需要细心品尝,领悟其中的滋味.

  16. A DOUBLE NEUTRON STAR MERGER ORIGIN FOR THE COSMOLOGICAL RELATIVISTIC FADING SOURCE PTF11agg?

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Xue-Feng; Gao, He; Ding, Xuan [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China); Zhang, Bing [Department of Physics and Astronomy, University of Nevada Las Vegas, Las Vegas, NV 89154 (United States); Dai, Zi-Gao [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China); Wei, Jian-Yan, E-mail: xfwu@pmo.ac.cn [National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China)

    2014-01-20

    The Palomar Transient Factory (PTF) team recently reported the discovery of a rapidly fading optical transient source, PTF11agg. A long-lived scintillating radio counterpart was identified, but the search for a high-energy counterpart showed negative results. The PTF team speculated that PTF11agg may represent a new class of relativistic outbursts. Here we suggest that a neutron star (NS)-NS merger system with a supra-massive magnetar central engine could be a possible source to power such a transient, if our line of sight is not on the jet axis direction of the system. These systems are also top candidates for gravitational wave sources to be detected in the advanced LIGO/Virgo era. We find that the PTF11agg data could be explained well with such a model, suggesting that at least some gravitational wave bursts due to NS-NS mergers may be associated with such a bright electromagnetic counterpart without a γ-ray trigger.

  17. Puzzles in physics

    Indian Academy of Sciences (India)

    Hsiang-Nan Li

    2006-11-01

    I discuss some puzzles observed in exclusive -meson decays, concentrating on the large difference between the direct CP asymmetries in the 0 → ∓± and ± → 0± modes, the large 0 → 00 branching ratio, and the large deviation of the mixing-induced CP asymmetries in the $b → sq\\bar{q}$ penguins from those in the $b → c\\bar{c}s$ trees.

  18. El puzzle de la pajarita

    OpenAIRE

    Flores, Pablo

    2002-01-01

    La enseñanza de las matemáticas en la escolaridad obligatoria está volviendo a valorar las cualidades educativas de la geometría sintética de formas, reconociendo el valor educativo de los recursos manipulativos como los puzzles. Son especialmente valorados los puzzles simples y versátiles. En este artículo queremos mostrar un puzzle que hemos ideado a partir de la descomposición de una figura familiar: el perfil de la pajarita de papel. El puzzle se compone sólo de tres piezas, por lo que es...

  19. Wooden Geometric Puzzles: Design and Hardness Proofs

    NARCIS (Netherlands)

    Alt, H.; Bodlaender, H.L.; Kreveld, M.J. van; Rote, G.; Tel, G.

    2007-01-01

    We discuss some new geometric puzzles and the complexity of their extension to arbitrary sizes. For gate puzzles and two-layer puzzles we prove NP-completeness of solving them. Not only the solution of puzzles leads to interesting questions, but also puzzle design gives rise to interesting theoretic

  20. Wooden Geometric Puzzles: Design and Hardness Proofs

    NARCIS (Netherlands)

    Alt, H.; Bodlaender, H.L.; Kreveld, M.J. van; Rote, G.; Tel, G.

    2008-01-01

    We discuss some new geometric puzzles and the complexity of their extension to arbitrary sizes. For gate puzzles and two-layer puzzles we prove NP-completeness of solving them. Not only the solution of puzzles leads to interesting questions, but also puzzle design gives rise to interesting theoretic

  1. The infinity puzzle

    CERN Document Server

    Close, Frank

    2011-01-01

    We are living in a Golden Age of Physics. Forty or so years ago, three brilliant, yet little-known scientists - an American, a Dutchman, and an Englishman - made breakthroughs which later inspired the construction of the Large Hadron Collider at CERN in Geneva: a 27 kilometer-long machine which has already costs ten billion dollars, taken twenty years to build, and now promises to reveal how the universe itself came to be. The Infinity Puzzle is the inside story of those forty years of research, breakthrough, and endeavour. Peter Higgs, Gerard 't Hooft and James Bjorken, were the three scienti

  2. The Entrepreneurial Earnings Puzzle

    DEFF Research Database (Denmark)

    Chen, Jing; Åstebro, Thomas

    2014-01-01

    underreporting by entrepreneurs. Using a nationwide panel survey representing U.S. households over 15 years, we estimate that entrepreneurs on average earn 4% less per year than employees. However, after correcting for income underreporting, the mean financial gain to entrepreneurship is positive and large......A review of recent evidence on relative earnings from entrepreneurship versus wage work presents a puzzle: why do individuals become entrepreneurs when entrepreneurs on average apparently earn less than employees? After considering several potential explanations, we empirically analyze one: income...

  3. Idiosyncratic Volatility Puzzle

    DEFF Research Database (Denmark)

    Aslanidis, Nektarios; Christiansen, Charlotte; Lambertides, Neophytos;

    from a large pool of macroeconomic and Önancial variables. Cleaning for macro-Önance e§ects reverses the puzzling negative relation between returns and idiosyncratic volatility documented previously. Portfolio analysis shows that the e§ects from macro-Önance factors are economically strong......In this paper, we scrutinize the cross-sectional relation between idiosyncratic volatility and stock returns. As a novelty, the idiosyncratic volatility is obtained by conditioning upon macro-Önance factors as well as upon traditional asset pricing factors. The macro-Önance factors are constructed...

  4. Determination of Solid State Solubility of the Components in the Ag-Ge Film System

    Directory of Open Access Journals (Sweden)

    A.A. Minenkov

    2014-11-01

    Full Text Available The efficiency of determination of solid state solubility of the components in the system with an eutectic type of interaction (Ag-Ge by means of measuring the sample electrical resistance during thermal cycling has been shown. Film systems were formed in a vacuum by sequential condensation of components. The solubility curve of germanium in silver, obtained from the study of the samples with silver film thickness of 100 nm, is in good agreement with available literature data. The activation energy of grain-boundary diffusion has been estimated as 0,8 eV.

  5. Techniques for Solving Sudoku Puzzles

    CERN Document Server

    Chi, Eric C

    2012-01-01

    Solving Sudoku puzzles is one of the most popular pastimes in the world. Puzzles range in difficulty from easy to very challenging; the hardest puzzles tend to have the most empty cells. The current paper compares the performance of three computer algorithms in solving puzzles. Backtracking, simulated annealing, and alternating projections are generic methods for attacking combinatorial optimization problems. Our results favor backtracking. It infallibly solves Sudoku puzzles or deduces that a unique solution does not exist. However, backtracking does not scale well in high-dimensional combinatorial optimization. Hence, it is useful to expose statistics students to the other two solution techniques in a concrete setting. Simulated annealing shares a common structure with MCMC (Markov chain Monte Carlo) and enjoys wide applicability. The method of alternating projections solves the feasibility problem in convex programming. Converting a discrete optimization problem into a continuous optimization problem opens...

  6. The Puzzling Ophiuchus Stream

    Science.gov (United States)

    Kohler, Susanna

    2016-01-01

    Dwarf galaxies or globular clusters orbiting the Milky Way can be pulled apart by tidal forces, leaving behind a trail of stars known as a stellar stream. One such trail, the Ophiuchus stream, has posed a serious dynamical puzzle since its discovery. But a recent study has identified four stars that might help resolve this streams mystery.Conflicting TimescalesThe stellar stream Ophiuchus was discovered around our galaxy in 2014. Based on its length, which appears to be 1.6 kpc, we can calculate the time that has passed since its progenitor was disrupted and the stream was created: ~250 Myr. But the stars within it are ~12 Gyr old, and the stream orbits the galaxy with a period of ~350 Myr.Given these numbers, we can assume that Ophiuchuss progenitor completed many orbits of the Milky Way in its lifetime. So why would it only have been disrupted 250 million years ago?Fanning StreamLed by Branimir Sesar (Max Planck Institute for Astronomy), a team of scientists has proposed an idea that might help solve this puzzle. If the Ophiuchus stellar stream is on a chaotic orbit common in triaxial potentials, which the Milky Ways may be then the stream ends can fan out, with stars spreading in position and velocity.The fanned part of the stream, however, would be difficult to detect because of its low surface brightness. As a result, the Ophiuchus stellar stream could actually be longer than originally measured, implying that it was disrupted longer ago than was believed.Search for Fan StarsTo test this idea, Sesar and collaborators performed a search around the ends of the stream, looking for stars thatare of the right type to match the stream,are at the predicted distance of the stream,are located near the stream ends, andhave velocities that match the stream and dont match the background halo stars.Histogram of the heliocentric velocities of the 43 target stars. Six stars have velocities matching the stream velocity. Two of these are located in the main stream; the other

  7. Basic Functional Analysis Puzzles of Spectral Flow

    DEFF Research Database (Denmark)

    Booss-Bavnbek, Bernhelm

    2011-01-01

    We explain an array of basic functional analysis puzzles on the way to general spectral flow formulae and indicate a direction of future topological research for dealing with these puzzles.......We explain an array of basic functional analysis puzzles on the way to general spectral flow formulae and indicate a direction of future topological research for dealing with these puzzles....

  8. Carex flava agg. (section Ceratocystis, Cyperaceae in Poland: taxonomy, morphological variation, and soil conditions

    Directory of Open Access Journals (Sweden)

    Więcław Helena

    2014-03-01

    Full Text Available Sedges of Carex flava agg., typical of moist or wet habitats, are difficult to classify because of a lack of clear-cut morphological differences between them and the existence of numerous hybrids. This monograph presents results of research conducted in 2007-2012 in various parts of Poland. The plant material consisted of 1852 living specimens of Carex flava agg., collected from 80 localities, and dried specimens from 26 herbaria and from 7 private collections. The analysis involved 45 morphological characters (34 quantitative and 11 qualitative and 9 soil parameters. Univariate, bivariate, and multivariate statistical methods were used to process the data. The results confirm the taxonomic classification dividing the C. flava group into 4 species: C. flava s.s., C. lepidocarpa, C. demissa, and C. viridula. This classification is based on (i a high observed level of morphological separation of these taxa, resulting mostly from differences in generative characters, i.e. length of the utricle and its beak, and percentage ratio of beak length to total utricle length; (ii integrity of the taxa at the sites where they coexist, although some intermediate forms resulting from hybridization are also present; (iii habitat preferences of the taxa, especially the preference of C. lepidocarpa for calcareous sites and of C. demissa for slightly acidic soils. Thus in Poland the analysed taxa are morphologically well-defined and show clear ecological preferences. Continuous variation of morphological characters was observed among specimens of C. viridula, so it is not justifiable to distinguish its subspecies (sometimes classified even as separate species, described previously in literature. Consequently, the 2 subgroups of C. viridula were treated as local variants (i.e. varieties: var. viridula and var. pulchella, considering their different habitat requirements. Additionally, 5 hybrids were distinguished within C. flava agg.: C. ×alsatica [= C. demissa

  9. Puzzled by GRB 060218

    CERN Document Server

    Ghisellini, G; Tavecchio, F

    2006-01-01

    We study the optical-UV/X-ray spectral energy distribution of GRB 060218 during the prompt phase and during what seems to be the afterglow phase. The results are puzzling, since if the opt-UV and the X-ray emission belong to a single black body, then its luminosity is too large, and it cannot be interpreted as the signature of the supernova shock breakout. Problems are also encountered in associating the expected supernova shock breakout emission with either the opt-UV or the X-ray emission. In the former case we derive too small ejecta velocities; in the latter case, on the contrary, the required velocity is too large. We then present what we think is the most conservative alternative explanation, namely a synchrotron spectrum, self-absorbed in the opt-UV and extending up to the X-ray band, where we observe the emission of the most energetic electrons, which are responsible for the exponential roll-over of the spectrum. The fit to the data is quite satisfactory, and can explain the entire spectrum except the...

  10. Expression of terrain and surface geology in high-resolution helicopter-borne gravity gradient (AGG) data: examples from Great Sand Dunes National Park, Rio Grande Rift, Colorado

    Science.gov (United States)

    Drenth, Benjamin J.

    2013-01-01

    Airborne gravity gradient (AGG) data are rapidly becoming standard components of geophysical mapping programs, due to their advantages in cost, access, and resolution advantages over measurements of the gravity field on the ground. Unlike conventional techniques that measure the gravity field, AGG methods measure derivatives of the gravity field. This means that effects of terrain and near-surface geology are amplified in AGG data, and that proper terrain corrections are critically important for AGG data processing. However, terrain corrections require reasonable estimates of density for the rocks and sediments that make up the terrain. A recommended philosophical approach is to use the terrain and surface geology, with their strong expression in AGG data, to the interpreter’s advantage. An example of such an approach is presented here for an area with very difficult ground access and little ground gravity data. Nettleton-style profiling is used with AGG data to estimate the densities of the sand dunefield and adjacent Precambrian rocks from the area of Great Sand Dunes National Park in southern Colorado. Processing of the AGG data using the density estimate for the dunefield allows buried structures, including a hypothesized buried basement bench, to be mapped beneath the sand dunes.

  11. Famous puzzles of great mathematicians

    CERN Document Server

    Petković, Miodrag S

    2009-01-01

    This entertaining book presents a collection of 180 famous mathematical puzzles and intriguing elementary problems that great mathematicians have posed, discussed, and/or solved. The selected problems do not require advanced mathematics, making this book accessible to a variety of readers. Mathematical recreations offer a rich playground for both amateur and professional mathematicians. Believing that creative stimuli and aesthetic considerations are closely related, great mathematicians from ancient times to the present have always taken an interest in puzzles and diversions. The goal of this

  12. À chacun son puzzle

    Directory of Open Access Journals (Sweden)

    Jean-Noël Ferrié

    2012-05-01

    Full Text Available Le texte soutient que le « tournant naturaliste » que l’on nous invite à négocier ne donne aucun moyen supplémentaire pour parvenir à une description perspicace de ce que les gens font dans des circonstances précises, l’existence humaine pouvant être considérée comme une collection de circonstances précises. Sans doute le naturalisme nous permet-il de comprendre comment certaines actions humaines sont possibles, mais cela ne nous dit pas pourquoi et comment elles font sens pour tout un chacun. La méthodologie nécessaire pour éclaircir le premier point obscurcit généralement le second. Le mieux est donc de considérer que les deux approches ne vont pas de pair. Ce point de vue est soutenu à partir d’exemple tirés de l’anthropologie de la religion.To each one his puzzle. For a serene methodological pluralismThe text argues that the « naturalistic turn » that we are invited to negotiate does not give any additional means to achieve an insightful description of what people do in specific circumstances, and human existence can be considered as a collection of specific circumstances. Probably naturalism allows us to understand how some human actions are possible, but that does not tell us why and how they make sense for everyone. The methodology needed to clarify the first point usually obscures the second one. The best way is to consider that the two approaches do not go together. The text supports this view from an example drawn from the anthropology of religion.A cada uno su rompecabezas. En favor de un pluralismo metodológico serenoEl texto argumenta que la inflexión naturalista a la que se nos invita a participar no proporciona ningún medio suplementario que desemboque en una descripción perspicaz de lo que la gente hace en circunstancias concretas ya que la existencia humana puede ser considerada como una concatenación de circunstancias concretas. Sin duda el naturalismo nos permite comprender como son

  13. PTF11agg AS THE FIRST EVIDENCE FOR REVERSE SHOCK EMISSION FROM A POST-MERGER MILLISECOND MAGNETAR

    Energy Technology Data Exchange (ETDEWEB)

    Wang Lingjun; Dai Zigao, E-mail: dzg@nju.edu.cn [School of Astronomy and Space Science, Nanjing University, Nanjing (China)

    2013-09-10

    Based on the stiff equations of state of neutron stars (NS) and the discovery of high-mass NSs, it is highly probable that a NS-NS merger will result in a rapidly rotating massive magnetar. The central magnetar will dissipate its rotational energy to the outflow by injecting Poynting flux, which will become lepton-dominated so that a long-lasting reverse shock (RS) develops. We calculate the emission of the RS as well as the emission of forward shock (FS) and find that, in most cases, the RS emission is stronger than FS emission. It is found that the recently discovered transient, PTF11agg, can be neatly accounted for by the RS emission powered by a millisecond magnetar. Other alternative models have been considered and cannot explain the observed light curves well. We therefore suggest that PTF11agg is the first evidence for RS emission from a post-merger millisecond magnetar.

  14. Practical Client Puzzle from Repeated Squaring

    NARCIS (Netherlands)

    Jeckmans, A.

    2009-01-01

    Cryptographic puzzles have been proposed by Merkle [15] to relay secret information between parties over an insecure channel. Client puzzles, a type of cryptographic puzzle, have been proposed by Juels and Brainard [8] to defend a server against denial of service attacks. However there is no general

  15. AggNet: Deep Learning From Crowds for Mitosis Detection in Breast Cancer Histology Images.

    Science.gov (United States)

    Albarqouni, Shadi; Baur, Christoph; Achilles, Felix; Belagiannis, Vasileios; Demirci, Stefanie; Navab, Nassir

    2016-05-01

    The lack of publicly available ground-truth data has been identified as the major challenge for transferring recent developments in deep learning to the biomedical imaging domain. Though crowdsourcing has enabled annotation of large scale databases for real world images, its application for biomedical purposes requires a deeper understanding and hence, more precise definition of the actual annotation task. The fact that expert tasks are being outsourced to non-expert users may lead to noisy annotations introducing disagreement between users. Despite being a valuable resource for learning annotation models from crowdsourcing, conventional machine-learning methods may have difficulties dealing with noisy annotations during training. In this manuscript, we present a new concept for learning from crowds that handle data aggregation directly as part of the learning process of the convolutional neural network (CNN) via additional crowdsourcing layer (AggNet). Besides, we present an experimental study on learning from crowds designed to answer the following questions. 1) Can deep CNN be trained with data collected from crowdsourcing? 2) How to adapt the CNN to train on multiple types of annotation datasets (ground truth and crowd-based)? 3) How does the choice of annotation and aggregation affect the accuracy? Our experimental setup involved Annot8, a self-implemented web-platform based on Crowdflower API realizing image annotation tasks for a publicly available biomedical image database. Our results give valuable insights into the functionality of deep CNN learning from crowd annotations and prove the necessity of data aggregation integration.

  16. Construction-Paper Puzzle Masterpieces

    Science.gov (United States)

    Vance, Shelly

    2010-01-01

    Creating an appreciation of art history in her junior-high students has always been one of the author's greatest challenges as an art teacher. In this article, the author describes how her eighth-grade students re-created a famous work of art--piece by piece, like a puzzle or a stained-glass window--out of construction paper. (Contains 1 resource.)

  17. Neutron Star News and Puzzles

    CERN Document Server

    Prakash, Madappa

    2014-01-01

    Gerry Brown has had the most influence on my career in Physics, and my life after graduate studies. In this article, I give a brief account of some of the many ways in which Gerry shaped my research. Recent and on-going research on neutron stars in which the group built from scratch by Gerry at Stony Brook has made significant strides are reviewed. Selected puzzles about neutron stars that remain to be solved are noted.

  18. Neutron star news and puzzles

    Science.gov (United States)

    Prakash, Madappa

    2014-08-01

    Gerry Brown has had the most influence on my career in Physics, and my life after graduate studies. This article gives a brief account of some of the many ways in which Gerry shaped my research. Focus is placed on the significant strides on neutron star research made by the group at Stony Brook, which Gerry built from scratch. Selected puzzles about neutron stars that remain to be solved are noted.

  19. How to Solve the Torus Puzzle

    Directory of Open Access Journals (Sweden)

    Masahiro Nakamura

    2012-01-01

    Full Text Available In this paper, we consider the following sliding puzzle called torus puzzle. In an m by n board, there are mn pieces numbered from 1 to mn. Initially, the pieces are placed in ascending order. Then they are scrambled by rotating the rows and columns without the player’s knowledge. The objective of the torus puzzle is to rearrange the pieces in ascending order by rotating the rows and columns. We provide a solution to this puzzle. In addition, we provide lower and upper bounds on the number of steps for solving the puzzle. Moreover, we consider a variant of the torus puzzle in which each piece is colored either black or white, and we present a hardness result for solving it.

  20. Shortening of the Lactobacillus paracasei subsp. paracasei BGNJ1-64 AggLb protein switches its activity from auto-aggregation to biofilm formation

    Directory of Open Access Journals (Sweden)

    Marija Miljković

    2016-09-01

    Full Text Available AggLb is the largest (318.6 kDa aggregation-promoting protein of Lactobacillus paracasei subsp. paracasei BGNJ1-64 responsible for forming large cell aggregates, which causes auto-aggregation, collagen binding and pathogen exclusion in vitro. It contains an N-terminus leader peptide, followed by six successive collagen binding domains, 20 successive repeats (CnaB-like domains and an LPXTG sorting signal at the C-terminus for cell wall anchoring. Experimental information about the roles of the domains of AggLb is currently unknown. To define the domain that confers cell aggregation and the key domains for interactions of specific affinity between AggLb and components of the extracellular matrix (ECM, we constructed a series of variants of the aggLb gene and expressed them in Lactococcus lactis subsp. lactis BGKP1-20 using a lactococcal promoter. All of the variants contained a leader peptide, an inter collagen binding-CnaB domain region (used to raise an anti-AggLb antibody, an anchor domain and a different number of collagen binding and CnaB-like domains. The role of the collagen binding repeats of the N-terminus in auto-aggregation and binding to collagen and fibronectin was confirmed. Deletion of the collagen binding repeats II, III and IV resulted in a loss of the strong auto-aggregation, collagen and fibronectin binding abilities whereas the biofilm formation capability was increased. The strong auto-aggregation, collagen and fibronectin binding abilities of AggLb were negatively correlated to biofilm formation.

  1. Distribution of Pathogenic Genes aatA, aap, aggR, among Uropathogenic Escherichia coli (UPEC) and Their Linkage with StbA Gene.

    Science.gov (United States)

    Nazemi, A; Mirinargasi, M; Merikhi, N; Sharifi, S H

    2011-07-01

    Urinary tract infection (UTI) with E. coli (UPEC) is one of the most common bacterial infections among human beings. In addition to the host predisposing factors, genes are also proposed to have an important role in the occurrence of UTIs. This study investigated the distribution of three pathogenic genes including aggR, aap and aatA among UPEC infected samples and their linkage with stbA, the essential gene for maintaining of pAA plasmid. A total of 244 samples were collected from patients with UTIs through clinical laboratories located in western side of Tehran (Iran) during years 2008-2009. E. coli isolation was performed according to standard laboratory methods. DNAs were extracted from samples using Boiling method, and the presence of aap, aggR, aatA and stbA genes were investigated by PCR. No pathogenic genes (aap, aggR, aatA) were found in 104 out of 244 UPEC samples, while 14 of them were carrying stbA gene. Out of 140 UPEC samples with pathogenic genes, 94 (46.6%) were carrying aap gene, 52 (23%) aggR gene, and 80 (35.4%) aatA gene. A total of 18 samples were also carrying all pathogenic genes together. Moreover, 44 out of 144 samples were carrying stbA gene. The results obtained by this study showed that the aggR, aap and aatA pathogenic genes have different existence patterns in different E. coli strains that infect different organs. Our study also showed that these three plasmid genes in EAEC strains are able to transpose in the genome and change their level of linkage with pAA plasmid essential gene stbA. Meanwhile, this study confirmed that aggR, aap and aatA genes are not specific to only EAEC strains.

  2. Project-A-Puzzle. Second Edition.

    Science.gov (United States)

    Porter, Richard D.

    This set of transparency masters of mathematical puzzles has as its intent the development of logical and perceptual skills. The puzzles include patterns, magic squares, and counting problems. Solutions and follow-up suggestions are provided on the back of each page. (MP)

  3. The Magnets Puzzle is NP-Complete

    DEFF Research Database (Denmark)

    Kölker, Jonas

    2012-01-01

    In a Magnets puzzle, one must pack magnets in a box subjet to polarity and numeric constraints. We show that solvability of Magnets instances is NP-complete.......In a Magnets puzzle, one must pack magnets in a box subjet to polarity and numeric constraints. We show that solvability of Magnets instances is NP-complete....

  4. Automated Word Puzzle Generation via Topic Dictionaries

    CERN Document Server

    Pinter, Balazs; Szabo, Zoltan; Lorincz, Andras

    2012-01-01

    We propose a general method for automated word puzzle generation. Contrary to previous approaches in this novel field, the presented method does not rely on highly structured datasets obtained with serious human annotation effort: it only needs an unstructured and unannotated corpus (i.e., document collection) as input. The method builds upon two additional pillars: (i) a topic model, which induces a topic dictionary from the input corpus (examples include e.g., latent semantic analysis, group-structured dictionaries or latent Dirichlet allocation), and (ii) a semantic similarity measure of word pairs. Our method can (i) generate automatically a large number of proper word puzzles of different types, including the odd one out, choose the related word and separate the topics puzzle. (ii) It can easily create domain-specific puzzles by replacing the corpus component. (iii) It is also capable of automatically generating puzzles with parameterizable levels of difficulty suitable for, e.g., beginners or intermedia...

  5. Solving jigsaw puzzles using image features

    DEFF Research Database (Denmark)

    Nielsen, Ture R.; Drewsen, Peter; Hansen, Klaus

    2008-01-01

    algorithm which exploits the divide and conquer paradigm to reduce the combinatorially complex problem by classifying the puzzle pieces and comparing pieces drawn from the same group. The paper includes a brief preliminary investigation of some image features used in the classification.......In this article, we describe a method for automatic solving of the jigsaw puzzle problem based on using image features instead of the shape of the pieces. The image features are used for obtaining an accurate measure for edge similarity to be used in a new edge matching algorithm. The algorithm...... is used in a general puzzle solving method which is based on a greedy algorithm previously proved successful. We have been able to solve computer generated puzzles of 320 pieces as well as a real puzzle of 54 pieces by exclusively using image information. Additionally, we investigate a new scalable...

  6. Impossible folding puzzles and other mathematical paradoxes

    CERN Document Server

    Sarcone, Gianni A

    2014-01-01

    Do all problems have solutions? Is complexity synonymous with difficulty? This original collection of mathematical puzzles and paradoxes proves that things aren't always what they seem! Readers will discover that nothing is as easy or as difficult as it looks and that puzzles can have one, several, or no solutions.The fun-filled puzzles begin with The Tricky Hole, a challenge that involves pushing a large coin through a small hole in a sheet of paper without ripping or making any cuts in the paper. Advance to the Elastic Playing Card, in which it's possible to cut a hole into a playing card bi

  7. PSQP: Puzzle Solving by Quadratic Programming.

    Science.gov (United States)

    Andalo, Fernanda A; Taubin, Gabriel; Goldenstein, Siome

    2017-02-01

    In this article we present the first effective method based on global optimization for the reconstruction of image puzzles comprising rectangle pieces-Puzzle Solving by Quadratic Programming (PSQP). The proposed novel mathematical formulation reduces the problem to the maximization of a constrained quadratic function, which is solved via a gradient ascent approach. The proposed method is deterministic and can deal with arbitrary identical rectangular pieces. We provide experimental results showing its effectiveness when compared to state-of-the-art approaches. Although the method was developed to solve image puzzles, we also show how to apply it to the reconstruction of simulated strip-shredded documents, broadening its applicability.

  8. The Complexity of the Puzzles of Final Fantasy XIII-2

    CERN Document Server

    Johnston, Nathaniel

    2012-01-01

    We analyze the computational complexity of solving the three "temporal rift" puzzles in the recent popular video game Final Fantasy XIII-2. We show that the Tile Trial puzzle is NP-hard and we provide an efficient algorithm for solving the Crystal Bonds puzzle. We also show that slight generalizations of the Crystal Bonds and Hands of Time puzzles are NP-hard.

  9. The Puzzle of Rice Domestication

    Institute of Scientific and Technical Information of China (English)

    Tao Sang; Song Ge

    2007-01-01

    The origin of cultivated rice has puzzled plant biologists for decades. This is due, at least in part, to the complex evolutionary dynamics in rice cultivars and wild progenitors, particularly rapid adaptive differentiation and continuous gene flow within and between cultivated and wild rice. The long-standing controversy over single versus multiple and annual versus perennial origins of cultivated rice has been brought into shaper focus with the rapid accumulation of genetic and phylogenetic data. Molecular phylogenetic analyses revealed ancient genomic differentiation between rice cultivars, suggesting that they were domesticated from divergent wild populations. However, the recently cloned domestication gene sh4, responsible for the reduction of grain shattering from wild to cultivated rice, seems to have originated only once. Herein, we propose two models to reconcile apparently conflicting evidence regarding rice domestication. The snow-balling model considers a single origin of cultivated rice. In this model, a core of critical domestication alleles was fixed in the founding cultivar and then acted to increase the genetic diversity of cultivars through hybridization with wild populations. The combination model considers multiple origins of cultivated rice. In this model, initial cultivars were domesticated from divergent wild populations and fixed different sets of domestication alleles. Subsequent crosses among these semi-domesticated cultivars resulted in the fixation of a similar set of critical domestication alleles in the contemporary cultivars. In both models, introgression has played an important role in rice domestication. Recent and future introgression of beneficial genes from the wild gene pool through conventional and molecular breeding programs can be viewed as the continuation of domestication.

  10. Identification, quantification, spatiotemporal distribution and genetic variation of major latex secondary metabolites in the common dandelion (Taraxacum officinale agg.).

    Science.gov (United States)

    Huber, Meret; Triebwasser-Freese, Daniella; Reichelt, Michael; Heiling, Sven; Paetz, Christian; Chandran, Jima N; Bartram, Stefan; Schneider, Bernd; Gershenzon, Jonathan; Erb, Matthias

    2015-07-01

    The secondary metabolites in the roots, leaves and flowers of the common dandelion (Taraxacum officinale agg.) have been studied in detail. However, little is known about the specific constituents of the plant's highly specialized laticifer cells. Using a combination of liquid and gas chromatography, mass spectrometry and nuclear magnetic resonance spectrometry, we identified and quantified the major secondary metabolites in the latex of different organs across different growth stages in three genotypes, and tested the activity of the metabolites against the generalist root herbivore Diabrotica balteata. We found that common dandelion latex is dominated by three classes of secondary metabolites: phenolic inositol esters (PIEs), triterpene acetates (TritAc) and the sesquiterpene lactone taraxinic acid β-D-glucopyranosyl ester (TA-G). Purification and absolute quantification revealed concentrations in the upper mgg(-1) range for all compound classes with up to 6% PIEs, 5% TritAc and 7% TA-G per gram latex fresh weight. Contrary to typical secondary metabolite patterns, concentrations of all three classes increased with plant age. The highest concentrations were measured in the main root. PIE profiles differed both quantitatively and qualitatively between plant genotypes, whereas TritAc and TA-G differed only quantitatively. Metabolite concentrations were positively correlated within and between the different compound classes, indicating tight biosynthetic co-regulation. Latex metabolite extracts strongly repelled D. balteata larvae, suggesting that the latex constituents are biologically active.

  11. Exploring Organic Mechanistic Puzzles with Molecular Modeling

    Science.gov (United States)

    Horowitz, Gail; Schwartz, Gary

    2004-01-01

    The molecular modeling was used to reinforce more general skills such as deducing and drawing reaction mechanisms, analyzing reaction kinetics and thermodynamics and drawing reaction coordinate energy diagrams. This modeling was done through the design of mechanistic puzzles, involving reactions not familiar to the students.

  12. New data and an old puzzle

    DEFF Research Database (Denmark)

    Lee, S Hong; Byrne, Enda M; Hultman, Christina M;

    2015-01-01

    BACKGROUND: A long-standing epidemiological puzzle is the reduced rate of rheumatoid arthritis (RA) in those with schizophrenia (SZ) and vice versa. Traditional epidemiological approaches to determine if this negative association is underpinned by genetic factors would test for reduced rates of o...

  13. Reinforcing Geometric Properties with Shapedoku Puzzles

    Science.gov (United States)

    Wanko, Jeffrey J.; Nickell, Jennifer V.

    2013-01-01

    Shapedoku is a new type of puzzle that combines logic and spatial reasoning with understanding of basic geometric concepts such as slope, parallelism, perpendicularity, and properties of shapes. Shapedoku can be solved by individuals and, as demonstrated here, can form the basis of a review for geometry students as they create their own. In this…

  14. The Forward Premium Puzzle only emerges gradually

    NARCIS (Netherlands)

    K. Bernoth (Kerstin); J. von Hagen; C.G. de Vries (Casper)

    2007-01-01

    textabstractThe forward premium puzzle (FPP) is the negative correlation between the forward premium and the realized exchange rate return at maturities of a month and beyond. Some recent evidence shows that at maturities of multiple years and at the highest intra day frequency the correlation is po

  15. Puzzle Pedagogy: A Use of Riddles in Mathematics Education

    Science.gov (United States)

    Farnell, Elin

    2017-01-01

    In this article, I present a collection of puzzles appropriate for use in a variety of undergraduate courses, along with suggestions for relevant discussion. Logic puzzles and riddles have long been sources of amusement for mathematicians and the general public alike. I describe the use of puzzles in a classroom setting, and argue for their use as…

  16. A Resolution of the Purchasing Power Parity Puzzle

    DEFF Research Database (Denmark)

    Frydman, Roman; Goldberg, Michael D.; Johansen, Søren;

    the "Purchasing Power Parity puzzle". In this paper, we trace the puzzle to exchange rate modelers' use of the "Rational Expectations Hypothesis". We show that once imperfect knowledge is recognized, a monetary model is able to account for the puzzle, as well as other salient features of the data, including...

  17. Isolation, characterization, sequencing and crystal structure of charybdin, a type 1 ribosome-inactivating protein from Charybdis maritima agg.

    Science.gov (United States)

    Touloupakis, Eleftherios; Gessmann, Renate; Kavelaki, Kalliopi; Christofakis, Emmanuil; Petratos, Kyriacos; Ghanotakis, Demetrios F

    2006-06-01

    A novel, type 1 ribosome-inactivating protein designated charybdin was isolated from bulbs of Charybdis maritima agg. The protein, consisting of a single polypeptide chain with a molecular mass of 29 kDa, inhibited translation in rabbit reticulocytes with an IC50 of 27.2 nm. Plant genomic DNA extracted from the bulb was amplified by PCR between primers based on the N-terminal and C-terminal sequence of the protein from dissolved crystals. The complete mature protein sequence was derived by partial DNA sequencing and terminal protein sequencing, and was confirmed by high-resolution crystal structure analysis. The protein contains Val at position 79 instead of the conserved Tyr residue of the ribosome-inactivating proteins known to date. To our knowledge, this is the first observation of a natural substitution of a catalytic residue at the active site of a natural ribosome-inactivating protein. This substitution in the active site may be responsible for the relatively low in vitro translation inhibitory effect compared with other ribosome-inactivating proteins. Single crystals were grown in the cold room from PEG6000 solutions. Diffraction data collected to 1.6 A resolution were used to determine the protein structure by the molecular replacement method. The fold of the protein comprises two structural domains: an alpha + beta N-terminal domain (residues 4-190) and a mainly alpha-helical C-terminal domain (residues 191-257). The active site is located in the interface between the two domains and comprises residues Val79, Tyr117, Glu167 and Arg170.

  18. On the B -> pi pi puzzle

    CERN Document Server

    Li, H; Li, Hsiang-nan; Mishima, Satoshi

    2006-01-01

    We investigate the resolutions in the literature to the B -> pi pi puzzle arising from the large observed B^0 -> pi^0 pi^0 branching ratio, and conclude that the puzzle still stands. The next-to-leading-order (NLO) contributions from the vertex corrections, the quark loops, and the magnetic penguin evaluated in the perturbative QCD approach, having saturated the experimental upper bound of the B^0 -> rho^0 rho^0 branching ratio, do not help. The inclusion of the NLO jet function from the soft-collinear effective theory into the QCD-improved factorization approach, though enhancing the B^0 -> pi^0 pi^0 branching ratio sufficiently, deteriorates the predictions for the B^\\pm -> pi^0 K^\\pm and B^0 -> pi^\\mp K^\\pm direct CP asymmetries, and overshoots the bound of the B^0 -> rho^0 rho^0 branching ratio. The effect of final-state interaction through either elastic or inelastic channels has been constrained by the B -> pi K data, and is not enough to resolve the B -> pi pi puzzle.

  19. Early puzzle play: a predictor of preschoolers' spatial transformation skill.

    Science.gov (United States)

    Levine, Susan C; Ratliff, Kristin R; Huttenlocher, Janellen; Cannon, Joanna

    2012-03-01

    Individual differences in spatial skill emerge prior to kindergarten entry. However, little is known about the early experiences that may contribute to these differences. The current study examined the relation between children's early puzzle play and their spatial skill. Children and parents (n = 53) were observed at home for 90 min every 4 months (6 times) between 2 and 4 years of age (26 to 46 months). When children were 4 years 6 months old, they completed a spatial task involving mental transformations of 2-dimensional shapes. Children who were observed playing with puzzles performed better on this task than those who did not, controlling for parent education, income, and overall parent word types. Moreover, among those children who played with puzzles, frequency of puzzle play predicted performance on the spatial transformation task. Although the frequency of puzzle play did not differ for boys and girls, the quality of puzzle play (a composite of puzzle difficulty, parent engagement, and parent spatial language) was higher for boys than for girls. In addition, variation in puzzle play quality predicted performance on the spatial transformation task for girls but not for boys. Implications of these findings as well as future directions for research on the role of puzzle play in the development of spatial skill are discussed.

  20. Nature's Greatest Puzzles

    Energy Technology Data Exchange (ETDEWEB)

    Quigg, Chris; /Fermilab

    2005-02-01

    It is a pleasure to be part of the SLAC Summer Institute again, not simply because it is one of the great traditions in our field, but because this is a moment of great promise for particle physics. I look forward to exploring many opportunities with you over the course of our two weeks together. My first task in talking about Nature's Greatest Puzzles, the title of this year's Summer Institute, is to deconstruct the premise a little bit.

  1. Last piece of the puzzle for ATLAS

    CERN Multimedia

    Clare Ryan

    At around 15.40 on Friday 29th February the ATLAS collaboration cracked open the champagne as the second of the small wheels was lowered into the cavern. Each of ATLAS' small wheels are 9.3 metres in diameter and weigh 100 tonnes including the massive shielding elements. They are the final parts of ATLAS' muon spectrometer. The first piece of ATLAS was installed in 2003 and since then many detector elements have journeyed down the 100 metre shaft into the ATLAS underground cavern. This last piece completes this gigantic puzzle.

  2. Manchester's Magiscope: An Interesting Optics Puzzle

    Science.gov (United States)

    Lancor, Rachael; Lancor, Brian

    2017-02-01

    The Magiscope was an attraction at Manchester's department store in Madison, WI, in 1939 that allowed children to peek into Santa's workshop (as shown in Fig. 1). The "magiscope" was a telescope-like device that gave children the illusion they were looking at a distant Santa, when in fact they were looking at a fabricated workshop on an upper level of the department store. In this article, we describe how we used the puzzle of the magiscope as a final assessment for our optics unit in an introductory physics course.

  3. The China puzzle: Opportunities for accounting research

    Institute of Scientific and Technical Information of China (English)

    Suresh; Radhakrishnan

    2014-01-01

    How can China achieve phenomenal economic growth despite what is considered as "weak" institutions in market-based economies? Xu(2011) provides a framework to understand this puzzle. Specifically, he suggests that China’s institutional framework of Regionally Decentralized Authoritarian regime was likely responsible for the phenomenal economic growth despite what is considered "weak" institutions for market-based economies. While recent accounting research provides insights into the relationship between agency issues, and accounting and control systems in the China context, accounting researchers can use the institutional feature of RDAs to provide insights into the role of accounting and control systems in non-market-based settings.

  4. WAIS-IV visual puzzles in a mixed clinical sample.

    Science.gov (United States)

    Fallows, Robert R; Hilsabeck, Robin C

    2012-01-01

    Little is known about which cognitive functions underlie the new Visual Puzzles subtest of the Wechsler Adult Intelligence Scale - Fourth Edition (WAIS-IV). The purpose of this study was to investigate relationships between Visual Puzzles and common neuropsychological measures in a mixed clinical sample. A total of 44 veterans (75% men) were administered the WAIS-IV as part of a neuropsychological evaluation. Average age was 47.4 years (SD = 11.8), and average education was 13.8 years (SD = 2.3). Correlations were conducted to examine relationships between Visual Puzzles, demographic variables, and neuropsychological measures. Hierarchical regression analysis was used to determine which measures contributed the most variance to Visual Puzzles. Visual Puzzles correlated significantly with measures of visuospatial reasoning, verbal learning and recall, mental flexibility, processing speed, and naming, which accounted for 50% of the variance in Visual Puzzles performance. The results indicate that Visual Puzzles is not a pure measure of visuoperceptual reasoning, at least in a mixed clinical sample, because memory, mental flexibility, processing speed, and language abilities also contribute to successful performance of the task. Thus it may be important to consider other aspects of cognitive functioning when interpreting Visual Puzzles performance.

  5. Crossword Puzzles as Learning Tools in Introductory Soil Science

    Science.gov (United States)

    Barbarick, K. A.

    2010-01-01

    Students in introductory courses generally respond favorably to novel approaches to learning. To this end, I developed and used three crossword puzzles in spring and fall 2009 semesters in Introductory Soil Science Laboratory at Colorado State University. The first hypothesis was that crossword puzzles would improve introductory soil science…

  6. The Crossword Puzzle as a Teaching Examination Tool.

    Science.gov (United States)

    Borcher, Glenda; And Others

    1994-01-01

    Animal science students (n=107) answered questions in both crossword puzzle and fill-in-the-blank format; 41 students in another study received either format as weekly review/quizzes. Students answered more questions correctly with crossword puzzles and enjoyed the challenge, although they appeared more willing to attempt answers with the fill-in…

  7. Sudoku Puzzles for First-Year Organic Chemistry Students

    Science.gov (United States)

    Perez, Alice L.; Lamoureux, G.

    2007-01-01

    Sudoku puzzle was designed to teach about amino acids and functional groups to the students of undergraduate organic chemistry students. The puzzles focus on helping the student learn the name, 3-letter code and 1-letter code of common amino acids and functional groups.

  8. The Puzzle of the Scandinavian Welfare State and Social Trust

    DEFF Research Database (Denmark)

    Svendsen, Gunnar Lind Haase; Svendsen, Gert Tinggaard

    2015-01-01

    The Scandinavian welfare model is a puzzle to economists: It works economically, even though free-riding should prevail with its explosive cocktail of high taxation and high social benefits. One overlooked solution to the puzzle could be the unique stock of social trust present in Scandinavia. Here...

  9. A Common Solution of Two Cosmic Puzzles

    CERN Document Server

    Dado, Shlomo

    2014-01-01

    The origin of the diffuse extragalactic gamma-ray background, which was measured with the large area telescope (LAT) aboard the Fermi satellite at energy below 820 GeV, and of the diffuse cosmic background of neutrinos, which was observed at much higher energies with the IceCube detector deep under the south pole ice, are among the current unsolved major cosmic puzzles. Here we show that their properties indicate a common origin: the decay of mesons produced in collisions of cosmic rays accelerated in relativistic jets with matter in/near source. Moreover, their properties are those expected if their common source is the highly relativistic jets that produce the long duration gamma ray bursts in core collapse supernovae of type Ic, which take place mostly in the densest regions of giant molecular clouds in star forming galaxies.

  10. Resolution to the B -> pi K puzzle

    CERN Document Server

    Li, H; Sanda, A I; Li, Hsiang-nan; Mishima, Satoshi

    2005-01-01

    We calculate the important next-to-leading-order contributions to the B -> pi K, pi pi decays from the vertex corrections, the quark loops, and the magnetic penguins in the perturbative QCD approach. It is found that the latter two reduce the leading-order penguin amplitudes by about 10%, and modify only the B -> pi K branching ratios. The main effect of the vertex corrections is to increase the small color-suppressed tree amplitude by a factor of 3, which then resolves the large difference between the direct CP asymmetries of the B^0 -> pi^\\mp K^\\pm and B^\\pm -> pi^0 K^\\pm modes. The puzzle from the large B^0 -> pi^0 pi^0 branching ratio still remains.

  11. Puzzle of the $\\Lambda_c$ spectrum

    CERN Document Server

    Lü, Qi-Fang; Liu, Xiang; Matsuki, Takayuki

    2016-01-01

    There is a puzzle in the $\\Lambda_c^+$ family, i.e., one member with $J^P=3/2^+$ is missing in a $L=2$ multiplet which the heavy quark effective theory predicts, and $J^P$'s of $\\Lambda_c(2765)^+$ and $\\Lambda_c(2940)^+$ are unknown. Using a light diquark picture to calculate baryon masses, we study possible assignments of two $\\Lambda_c$'s with unknown $J^P$ and the missing $\\Lambda_c^+$ with $3/2^+$ for $L=2$, and we find the most probable possibility that the peak corresponding to $\\Lambda_c(2880)^+$ actually includes a missing member with spin $3/2^+$ for $L=2$ and that quantum numbers of $\\Lambda_c(2765)^+$ and $\\Lambda_c(2940)^+$ are $2S(1/2^+)$ and $2P(1/2^-)$, respectively.

  12. Matter-antimatter puzzle: LHCb improves resolution

    CERN Multimedia

    Antonella Del Rosso

    2012-01-01

    In 2010, Fermilab’s DØ experiment reported a one percent difference in the properties of matter and antimatter in decays of B mesons (that is, particles containing beauty quarks) to muons. Saturday, at the ICHEP Conference in Melbourne, the LHCb experiment at CERN presents new results, which do not confirm this anomaly and are consistent with the Standard Model predictions. The same experiment has also presented the first evidence of asymmetry arising in other decays of the same family of mesons. The image becomes clearer but the puzzle has not yet been solved.   Inside the LHCb detector. The matter-antimatter imbalance in the Universe is a very hot topic in physics. The conundrum arises from the fact that, although objects made of antimatter are not observed in the Universe, theory predicts that matter and antimatter be created equally in particle interactions and in the Big Bang. Only small deviations from this very symmetric behaviour are incorporated in the theory. E...

  13. Heavy quarkonium: progress, puzzles, and opportunities

    CERN Document Server

    Brambilla, N; Heltsley, B K; Vogt, R; Bodwin, G T; Eichten, E; Frawley, A D; Meyer, A B; Mitchell, R E; Papadimitriou, V; Petreczky, P; Petrov, A A; Robbe, P; Vairo, A; Andronic, A; Arnaldi, R; Artoisenet, P; Bali, G; Bertolin, A; Bettoni, D; Brodzicka, J; Bruno, G E; Caldwell, A; Catmore, J; Chang, C H; Chao, K T; Chudakov, E; Cortese, P; Crochet, P; Drutskoy, A; Ellwanger, U; Faccioli, P; Gabareen Mokhtar, A; Garcia i Tormo, X; Hanhart, C; Harris, F A; Kaplan, D M; Klein, S R; Kowalski, H; Lansberg, J P; Levichev, E; Lombardo, V; Lourenco, C; Maltoni, F; Mocsy, A; Mussa, R; Navarra, F S; Negrini, M; Nielsen, M; Olsen, S L; Pakhlov, P; Pakhlova, G; Peters, K; Polosa, A D; Qian, W; Qiu, J W; Rong, G; Sanchis-Lozano, M A; Scomparin, E; Senger, P; Simon, F; Stracka, S; Sumino, Y; Voloshin, M; Weiss, C; Wohri, H K; Yuan, C Z

    2011-01-01

    A golden age for heavy quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the $B$-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA, JLab, and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing ...

  14. The electron screening puzzle and nuclear clustering

    Science.gov (United States)

    Spitaleri, C.; Bertulani, C. A.; Fortunato, L.; Vitturi, A.

    2016-04-01

    Accurate measurements of nuclear reactions of astrophysical interest within, or close to, the Gamow peak show evidence of an unexpected effect attributed to the presence of atomic electrons in the target. The experiments need to include an effective "screening" potential to explain the enhancement of the cross sections at the lowest measurable energies. Despite various theoretical studies conducted over the past 20 years and numerous experimental measurements, a theory has not yet been found that can explain the cause of the exceedingly high values of the screening potential needed to explain the data. In this letter we show that instead of an atomic physics solution of the "electron screening puzzle", the reason for the large screening potential values is in fact due to clusterization effects in nuclear reactions, in particular for reaction involving light nuclei.

  15. Puzzling through General Chemistry: A Light-Hearted Approach to Engaging Students with Chemistry Content

    Science.gov (United States)

    Boyd, Susan L.

    2007-01-01

    Several puzzles are designed to be used by chemistry students as learning tools and teach them basic chemical concepts. The topics of the puzzles are based on the chapters from Chemistry, The Central Science used in general chemistry course and the puzzles are in various forms like crosswords, word searches, number searches, puzzles based on…

  16. Latest Zika Puzzle: How U.S. Patient Infected Caregiver

    Science.gov (United States)

    ... https://medlineplus.gov/news/fullstory_159925.html Latest Zika Puzzle: How U.S. Patient Infected Caregiver Officials say ... MONDAY, July 18, 2016 (HealthDay News) -- The mysterious Zika virus continues to surprise health scientists. On Monday, ...

  17. Formative Assessment Probes: Mountaintop Fossil: A Puzzling Phenomenon

    Science.gov (United States)

    Keeley, Page

    2015-01-01

    This column focuses on promoting learning through assessment. This month's issue describes using formative assessment probes to uncover several ways of thinking about the puzzling discovery of a marine fossil on top of a mountain.

  18. Local associations and the barium puzzle

    CERN Document Server

    Reddy, Arumalla B S

    2015-01-01

    We have observed high-dispersion echelle spectra of main-sequence stars in five nearby young associations -- Argus, Carina-Near, Hercules-Lyra, Orion and Subgroup B4 -- and derived abundances for elements ranging from Na to Eu. These are the first chemical abundance measurements for two of the five associations, while the remaining three associations are analysed more extensively in our study. Our results support the presence of chemical homogeneity among association members with a typical star-to-star abundance scatter of about 0.06 dex or less over many elements. The five associations show log$\\epsilon$(Li) consistent with their age and share a solar chemical composition for all elements with the exception of Ba. We find that all the heavy elements (Y, Zr, La, Ce, Nd, Sm and Eu) exhibit solar ratios, i.e., [X/Fe] $\\simeq$ 0, while Ba is overabundant by about 0.2-0.3 dex. The origin of the overabundance of Ba is a puzzle. Within the formulation of the s-process, it is difficult to create a higher Ba abundanc...

  19. Heavy quarkonium: progress, puzzles, and opportunities

    Energy Technology Data Exchange (ETDEWEB)

    Brambilla, N; Heltsley, B K; Vogt, R; Bodwin, G T; Eichten, E; Frawley, A D; Meyer, A B; Mitchell, R E; Papdimitriou, V; Petreczky, P; Petrov, A A; Robbe, P; Vairo, A; Andronic, A; Arnaldi, R; Artoisenet, P; Bali, G; Bertolin, A; Bettoni, D; Brodzicka, J; Bruno, G E; Caldwell, A; Catmore, J; Chang, C -H; Chao, K -T; Chudakov, E; Cortese, P; Crochet, P; Drutskoy, A; Ellwanger, U; Faccioli, P; Gabareen Mokhtar, A; Garcia i Tormo, X; Hanhart, C; Harris, F A; Kaplan, D M; Klein, S R; Kowalski, H; Lansberg, J -P; Levichev, E; Lombardo, V; Loureno, C; Maltoni, F; Mocsy, A; Mussa, R; Navarra, F S; Negrini, M; Nielsen, M; Olsen, S L; Pakhlov, P; Pakhlova, G; Peters, K; Polosa, A D; Qian, W; Qiu, J -W; Rong, G; Sanchis-Lozano, M A; Scomparin, E; Senger, P; Simon, F; Stracka, S; Sumino, Y; Voloshin, M; Weiss, C; Wohri, H K; Yuan, C -Z

    2011-02-01

    A golden age for heavy quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the $B$-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA, JLab, and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations. The plethora of newly-found quarkonium-like states unleashed a flood of theoretical investigations into new forms of matter such as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of c\\bar{c}, b\\bar{b}, and b\\bar{c} bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hot- and cold-nuclear-matter effects in quark-gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.

  20. Local associations and the barium puzzle

    Science.gov (United States)

    Reddy, Arumalla B. S.; Lambert, David L.

    2015-12-01

    We have observed high-dispersion echelle spectra of main-sequence stars in five nearby young associations - Argus, Carina-Near, Hercules-Lyra, Orion and Subgroup B4 - and derived abundances for elements ranging from Na to Eu. These are the first chemical abundance measurements for two of the five associations, while the remaining three associations are analysed more extensively in our study. Our results support the presence of chemical homogeneity among association members with a typical star-to-star abundance scatter of about 0.06 dex or less over many elements. The five associations show log ɛ(Li) consistent with their age and share a solar chemical composition for all elements with the exception of Ba. We find that all the heavy elements (Y, Zr, La, Ce, Nd, Sm and Eu) exhibit solar ratios, i.e. [X/Fe] ≃ 0, while Ba is overabundant by about 0.2-0.3 dex. The origin of the overabundance of Ba is a puzzle. Within the formulation of the s-process, it is difficult to create a higher Ba abundance without a similar increase in the s-process contributions to other heavy elements (La-Sm). Given that Ba is represented by strong lines of Ba II and La-Sm are represented by rather weak ionized lines, the suggestion, as previously made by other studies, is that the Ba abundance may be systematically overestimated by standard methods of abundance analysis perhaps because the upper reaches of the stellar atmospheres are poorly represented by standard model atmospheres. A novel attempt to analyse the Ba I line at 5535 Å gives a solar Ba abundance for stars with effective temperatures hotter than about 5800 K but increasingly subsolar Ba abundances for cooler stars with apparent Ba deficiencies of 0.5 dex at 5100 K. This trend with temperature may signal a serious non-local thermodynamical equilibrium effect on the Ba I line.

  1. Reconstructed structures of nanosized co islands on Ag/Ge(111) mean square root of 3 x mean square root of 3 surfaces.

    Science.gov (United States)

    Fu, Tsu-Yi; Tsay, Sung-Lin; Lin, Chun-Liang

    2008-02-01

    Structural evolution of Co/Ag/Ge(111) at high temperatures was studied by using scanning tunneling microscopy and low energy electron diffraction. The mean square root of 3 x mean square root of 3-Ag layer between the substrate Ge( 11) and Co adatoms can avoid the formation of Co-Ge compounds below 800 K. The Co atoms nucleate to form islands where mean square root of 13 x mean square root of 13 or 2 x 2 reconstructions were observed after annealing between 373 K and 737 K. The mean square root of 13 x mean square root of 13 structure with mirror symmetry relative to [-211], [11-2], and [1-21] axes was observed for 1-2 layer Co islands. Co islands with over 2 layers appear 2 x 2 structure. All reconstruction structures of the nano-sized Co islands and substrate Ag/Ge(111) mean square root of 3 x mean square root of 3 surface were analyzed using the atomic hard sphere model. The bright protrusions of these reconstructions all sit in the centers of Ag or Ge trimers, which were predicted to have maximum binding energy.

  2. International trade network: fractal properties and globalization puzzle.

    Science.gov (United States)

    Karpiarz, Mariusz; Fronczak, Piotr; Fronczak, Agata

    2014-12-12

    Globalization is one of the central concepts of our age. The common perception of the process is that, due to declining communication and transport costs, distance becomes less and less important. However, the distance coefficient in the gravity model of trade, which grows in time, indicates that the role of distance increases rather than decreases. This, in essence, captures the notion of the globalization puzzle. Here, we show that the fractality of the international trade system (ITS) provides a simple solution for the puzzle. We argue that the distance coefficient corresponds to the fractal dimension of ITS. We provide two independent methods, the box counting method and spatial choice model, which confirm this statement. Our results allow us to conclude that the previous approaches to solving the puzzle misinterpreted the meaning of the distance coefficient in the gravity model of trade.

  3. Lorentz violation in the gravity sector: the t puzzle

    CERN Document Server

    Bonder, Yuri

    2015-01-01

    Lorentz violation is a candidate quantum-gravity signal, and the Standard-Model Extension (SME) is a widely used parametrization of such violation. In the gravitational SME sector, there is an elusive coefficient for which no effects have been found. This is is known as the $t$ puzzle and, to date, it has no compelling explanation. In this paper, several approaches to understand the $t$ puzzle are proposed. First, redefinitions of the dynamical fields are studied, which reveal that other SME coefficients can be moved to nongravitational sectors. It is also shown that the gravity SME sector can be treated \\textit{\\`a la} Palatini, and that, in the presence of spacetime boundaries, it is possible to correct its action to get the desired equations of motion. Also, through a reformulation as a Lanczos-type tensor, some problematic features of the $t$ term, that should arise at the phenomenological level, are revealed. Additional potential explanations to the $t$ puzzle are outlined.

  4. International trade network: fractal properties and globalization puzzle

    CERN Document Server

    Karpiarz, Mariusz; Fronczak, Agata

    2014-01-01

    Globalization is one of the central concepts of our age. The common perception of the process is that, due to declining communication and transport costs, distance becomes less and less important. However, the distance coefficient in the gravity model of trade, which grows in time, indicates that the role of distance increases rather than decreases. This, in essence, captures the notion of the globalization puzzle. Here, we show that the fractality of the international trade system (ITS) provides a simple solution for the puzzle. We argue, that the distance coefficient corresponds to the fractal dimension of ITS. We provide two independent methods, box counting method and spatial choice model, which confirm this statement. Our results allow us to conclude that the previous approaches to solving the puzzle misinterpreted the meaning of the distance coefficient in the gravity model of trade.

  5. Games and puzzles for English as a second language

    CERN Document Server

    Fremont, Victoria

    2011-01-01

    Students can hone their verbal and grammatical skills with this entertaining workbook. Search-a-words, crossword puzzles, anagrams, and other challenges build vocabulary and spelling skills. They also help students understand and identify idioms, irregular past tenses and participles, and other linguistic stumbling blocks. Perfect for individual study or as a course supplement.

  6. A Jigsaw Puzzle Approach To Learning History in Introductory Psychology.

    Science.gov (United States)

    Krauss, Judith

    1999-01-01

    Believes that it may be daunting for some students to learn about the history of psychology. Describes a teaching strategy that uses jigsaw puzzles to teach about the historical terms of structuralism, functionalism, and gestalt psychology. Finds that students performed better on test questions related to these three concepts after using this…

  7. Ambiguity Aversion and Household Portfolio Choice Puzzles: Empirical Evidence

    NARCIS (Netherlands)

    S.G. Dimmock (Stephen); R.R.P. Kouwenberg (Roy); O.S. Mitchell (Olivia); K. Peijnenburg (Kim)

    2016-01-01

    markdownabstractWe test the relation between ambiguity aversion and five household portfolio choice puzzles: nonparticipation in equities, low allocations to equity, home-bias, own-company stock ownership, and portfolio under-diversification. In a representative US household survey, we measure ambig

  8. Unraveling "Braid": Puzzle Games and Storytelling in the Imperative Mood

    Science.gov (United States)

    Arnott, Luke

    2012-01-01

    "Unraveling Braid" analyzes how unconventional, non-linear narrative fiction can help explain the ways in which video games signify. Specifically, this essay looks at the links between the semiotic features of Jonathan Blow's 2008 puzzle-platform video game Braid and similar elements in Georges Perec's 1978 novel "Life A User's Manual," as well as…

  9. A Geometric Puzzle That Leads To Fibonacci Sequences.

    Science.gov (United States)

    Rulf, Benjamin

    1998-01-01

    Illustrates how mathematicians work and do mathematical research through the use of a puzzle. Demonstrates how general rules, then theorems develop from special cases. This approach may be used as a research project in high school classrooms or math club settings with the teacher helping to formulate questions, set goals, and avoid becoming…

  10. Teaching Proofs and Algorithms in Discrete Mathematics with Online Visual Logic Puzzles

    Science.gov (United States)

    Cigas, John; Hsin, Wen-Jung

    2005-01-01

    Visual logic puzzles provide a fertile environment for teaching multiple topics in discrete mathematics. Many puzzles can be solved by the repeated application of a small, finite set of strategies. Explicitly reasoning from a strategy to a new puzzle state illustrates theorems, proofs, and logic principles. These provide valuable, concrete…

  11. Puzzles in modern biology. I. Male sterility, failure reveals design [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Steven A. Frank

    2016-09-01

    Full Text Available Many human males produce dysfunctional sperm. Various plants frequently abort pollen. Hybrid matings often produce sterile males. Widespread male sterility is puzzling. Natural selection prunes reproductive failure. Puzzling failure implies something that we do not understand about how organisms are designed. Solving the puzzle reveals the hidden processes of design.

  12. The Effect of Monetary Policy on Exchange Rates : How to Solve the Puzzles

    NARCIS (Netherlands)

    Kumah, F.Y.

    1996-01-01

    Recent empirical research on the effects of monetary policy shocks on exchange rate fluctuations have encountered the exchange rate puzzle and th e forward discount bias puzzle.The exchange rate puzzle is the tendency of the domestic currency (of non-US G-7 countries) to depreciate against the US do

  13. Update On the Puzzling Boyajian's Star

    Science.gov (United States)

    Kohler, Susanna

    2016-09-01

    Photometric time series for a neighboring star thats 25 NNW of Boyajians Star. No significant long-term dimming is seen which constrains the size of potential material obscuring Boyajians Star. [Wright et al. 2016/Benjamin Montet]Whats causing the mysterious light-curve dips of the so-called alien megastructure star, Boyajians Star? A recent study analyzes a variety of possible explanations to determine which ones are the most plausible.An Unusual Light CurveEarlier this year, astronomer Tabetha Boyajian reported on the unusual light curve of the star KIC 8462852. This star, now nicknamed Tabbys Star or Boyajians Star, showsunusual dips on day-long timescales that are too large to be explained by planet transits or similar phenomena.In addition to these short dips in luminosity, recent observations have also indicated that the star has faded by roughly 20% over the past hundred years. What could be causing both the short-term dips in the stars light and the long-term dimming over a century?Could the dimming be caused by an alien megastructure built by an extraterrestrial civilization? The authors find that a spherical structure is very unlikely. [Danielle Futselaar/SETI International]Alien Megastructures? Or Another Explanation?Boyajians Star was vaulted into the media spotlight when astronomer Jason Wright (Pennsylvania State University and University of California, Berkeley) proposed that its unusual light curve could potentially be explained by a surrounding megastructure built by an extraterrestrial civilization.Now Wright is back with co-author Steinn Sigurdsson (Pennsylvania State University). In a new study, Wright and Sigurdsson analyze an extensive list of explanations for the puzzling apparent behavior of Boyajians Star, based on our latest knowledge about this strange object.The Realm of PossibilitiesHere are just a few possible causes of Boyajians Stars dimming, as well as the authors assessment of their plausibility. For the full list, see the authors

  14. The Monotonicity Puzzle: An Experimental Investigation of Incentive Structures

    Directory of Open Access Journals (Sweden)

    Jeannette Brosig

    2010-05-01

    Full Text Available Non-monotone incentive structures, which - according to theory - are able to induce optimal behavior, are often regarded as empirically less relevant for labor relationships. We compare the performance of a theoretically optimal non-monotone contract with a monotone one under controlled laboratory conditions. Implementing some features relevant to real-world employment relationships, our paper demonstrates that, in fact, the frequency of income-maximizing decisions made by agents is higher under the monotone contract. Although this observed behavior does not change the superiority of the non-monotone contract for principals, they do not choose this contract type in a significant way. This is what we call the monotonicity puzzle. Detailed investigations of decisions provide a clue for solving the puzzle and a possible explanation for the popularity of monotone contracts.

  15. Laser Spectroscopy of Muonic Hydrogen and the Puzzling Proton

    Science.gov (United States)

    Pohl, Randolf

    2016-09-01

    Laser spectroscopy of muonic hydrogen atoms, μp, has revealed a proton root-mean-square (rms) charge radius rE that is an order of magnitude more accurate than the CODATA world average from elastic electron-proton scattering and precision spectroscopy of regular (electronic) hydrogen. Interestingly, though, the value of rE from μp is 4%, or 7 combined standard deviations smaller than the CODATA value of rE. This discrepancy has been coined "proton radius puzzle". We summarize the experiment and give a brief overview of the theory in muonic hydrogen. Finally we discuss some possible scenarios for the resolution of the "proton radius puzzle".

  16. Four small puzzles that Rosetta doesn't solve.

    Directory of Open Access Journals (Sweden)

    Rhiju Das

    Full Text Available A complete macromolecule modeling package must be able to solve the simplest structure prediction problems. Despite recent successes in high resolution structure modeling and design, the Rosetta software suite fares poorly on small protein and RNA puzzles, some as small as four residues. To illustrate these problems, this manuscript presents Rosetta results for four well-defined test cases: the 20-residue mini-protein Trp cage, an even smaller disulfide-stabilized conotoxin, the reactive loop of a serine protease inhibitor, and a UUCG RNA tetraloop. In contrast to previous Rosetta studies, several lines of evidence indicate that conformational sampling is not the major bottleneck in modeling these small systems. Instead, approximations and omissions in the Rosetta all-atom energy function currently preclude discriminating experimentally observed conformations from de novo models at atomic resolution. These molecular "puzzles" should serve as useful model systems for developers wishing to make foundational improvements to this powerful modeling suite.

  17. Puzzles, paradoxes, and problem solving an introduction to mathematical thinking

    CERN Document Server

    Reba, Marilyn A

    2014-01-01

    Graphs: Puzzles and Optimization Graphical Representation and Search Greedy Algorithms and Dynamic Programming Shortest Paths, DNA Sequences, and GPS Systems Routing Problems and Optimal Circuits Traveling Salesmen and Optimal Orderings Vertex Colorings and Edge Matchings Logic: Rational Inference and Computer Circuits Inductive and Deductive Arguments Deductive Arguments and Truth-Tables Deductive Arguments and Derivations Deductive Logic and Equivalence Modeling Using Deductive Logic Probability: Predictions and Expectations Probability and Counting Counting and Unordered Outcomes Independen

  18. Pension Demand and Utility: The Life Annuity Puzzle

    OpenAIRE

    Tomáš Cipra

    2014-01-01

    This paper shows by means of the concept of utility that annuitization through life annui-ties or a pension can be an efficient instrument for the economic assurance of seniors. Various quantitative arguments are presented supporting this statement (e.g. annuity equivalent wealth [AEW] is calculated using Czech data). In conclusion, some practical arguments are mentioned regarding why the real demand on life annuities contradicts this result so that a so-called annuity puzzle arises in pensio...

  19. Asset pricing puzzles explained by incomplete Brownian equilibria

    DEFF Research Database (Denmark)

    Christensen, Peter Ove; Larsen, Kasper

    time interval in a money market account as well as a risky security. Besides establishing the existence of an equilibrium, our main result shows that the resulting equilibrium can display a lower risk-free rate and a higher risk premium relative to the usual Pareto efficient equilibrium in complete...... markets. Consequently, our model can simultaneously help explaining the risk-free rate and equity premium puzzles....

  20. PUZZLES – A CREATIVE WAY OF DEVELOPMENT OF LOGICAL THINKING

    Directory of Open Access Journals (Sweden)

    Milková, Eva

    2011-12-01

    Full Text Available Logical thinking of students should be enhanced at all levels of their studies. There are many possibilities how to achieve it. In the paper one possible way within the subjects “Discrete Mathematics” and “Discrete Methods and Optimization” dealing with graph theory and combinatorial optimization will be presented. These mathematical disciplines are powerful tools for teachers allowing them to develop logical thinking of students, increase their imagination and make them familiar with solutions to various problems. Thanks the knowledge gained within the subjects students should be able to describe various practical situations with the aid of graphs, solve the given problem expressed by the graph, and translate the solution back into the initial situation. Student engagement is crucial for successful education. Practical tasks and puzzles attract students to know more about the explained subject matter and to apply gained knowledge. There are an endless number of enjoyable tasks, puzzles and logic problems in books like “Mathematics is Fun”, in riddles magazines and on the Internet. In the paper, as an inspiration, four puzzles developing logical thinking appropriate to be solved using graph theory and combinatorial optimization will be introduced. On these puzzles of different level of difficulty the students’ ability to find out the appropriate graph-representation of the given task and solve it will be discussed as well. The author of the paper has been prepared with her students various multimedia applications dealing with objects appropriate to subject matter for more than 15 years. In the paper we also discuss a benefit of multimedia applications used as a support of subjects “Discrete Mathematics” and “Discrete Methods and Optimization”.

  1. Particle Filter with State Permutations for Solving Image Jigsaw Puzzles

    Science.gov (United States)

    Yang, Xingwei; Adluru, Nagesh; Latecki, Longin Jan

    2016-01-01

    We deal with an image jigsaw puzzle problem, which is defined as reconstructing an image from a set of square and non-overlapping image patches. It is known that a general instance of this problem is NP-complete, and it is also challenging for humans, since in the considered setting the original image is not given. Recently a graphical model has been proposed to solve this and related problems. The target label probability function is then maximized using loopy belief propagation. We also formulate the problem as maximizing a label probability function and use exactly the same pairwise potentials. Our main contribution is a novel inference approach in the sampling framework of Particle Filter (PF). Usually in the PF framework it is assumed that the observations arrive sequentially, e.g., the observations are naturally ordered by their time stamps in the tracking scenario. Based on this assumption, the posterior density over the corresponding hidden states is estimated. In the jigsaw puzzle problem all observations (puzzle pieces) are given at once without any particular order. Therefore, we relax the assumption of having ordered observations and extend the PF framework to estimate the posterior density by exploring different orders of observations and selecting the most informative permutations of observations. This significantly broadens the scope of applications of the PF inference. Our experimental results demonstrate that the proposed inference framework significantly outperforms the loopy belief propagation in solving the image jigsaw puzzle problem. In particular, the extended PF inference triples the accuracy of the label assignment compared to that using loopy belief propagation.

  2. Learning structural bioinformatics and evolution with a snake puzzle

    Directory of Open Access Journals (Sweden)

    Gonzalo S. Nido

    2016-12-01

    Full Text Available We propose here a working unit for teaching basic concepts of structural bioinformatics and evolution through the example of a wooden snake puzzle, strikingly similar to toy models widely used in the literature of protein folding. In our experience, developed at a Master’s course at the Universidad Autónoma de Madrid (Spain, the concreteness of this example helps to overcome difficulties caused by the interdisciplinary nature of this field and its high level of abstraction, in particular for students coming from traditional disciplines. The puzzle will allow us discussing a simple algorithm for finding folded solutions, through which we will introduce the concept of the configuration space and the contact matrix representation. This is a central tool for comparing protein structures, for studying simple models of protein energetics, and even for a qualitative discussion of folding kinetics, through the concept of the Contact Order. It also allows a simple representation of misfolded conformations and their free energy. These concepts will motivate evolutionary questions, which we will address by simulating a structurally constrained model of protein evolution, again modelled on the snake puzzle. In this way, we can discuss the analogy between evolutionary concepts and statistical mechanics that facilitates the understanding of both concepts. The proposed examples and literature are accessible, and we provide supplementary material (see ‘Data Availability’ to reproduce the numerical experiments. We also suggest possible directions to expand the unit. We hope that this work will further stimulate the adoption of games in teaching practice.

  3. Supersymmetry, the flavour puzzle and rare B decays

    Energy Technology Data Exchange (ETDEWEB)

    Straub, David Michael

    2010-07-14

    The gauge hierarchy problem and the flavour puzzle belong to the most pressing open questions in the Standard Model of particle physics. Supersymmetry is arguably the most popular framework of physics beyond the Standard Model and provides an elegant solution to the gauge hierarchy problem; however, it aggravates the flavour puzzle. In the first part of this thesis, I discuss several approaches to address the flavour puzzle in the minimal supersymmetric extension of the Standard Model and experimental tests thereof: supersymmetric grand unified theories with a unification of Yukawa couplings at high energies, theories with minimal flavour violation and additional sources of CP violation and theories with gauge mediation of supersymmetry breaking and a large ratio of Higgs vacuum expectation values. In the second part of the thesis, I discuss the phenomenology of two rare B meson decay modes which are promising probes of physics beyond the Standard Model: The exclusive B {yields} K{sup *}l{sup +}l{sup -} decay, whose angular decay distribution will be studied at LHC and gives access to a large number of observables and the b{yields}s{nu}anti {nu} decays, which are in the focus of planned high-luminosity Super B factories. I discuss the predictions for these observables in the Standard Model and their sensitivity to New Physics. (orig.)

  4. Precautionary Borrowing and the Credit Card Debt Puzzle

    DEFF Research Database (Denmark)

    Druedahl, Jeppe; Jørgensen, Casper Nordal

    2015-01-01

    This paper addresses the credit card debt puzzle using a generalization of the buffer-stock consumption model with long-term revolving debt contracts. Closely resembling actual US credit card law, we assume that card issuers can always deny their cardholders access to new debt, but that they cannot...... to simultaneously hold positive gross debt and positive gross assets even though the interest rate on the debt is much higher than the return rate on the assets. Including a risk of being excluded from new borrowing which is positively correlated with unemployment, we are able to simultaneously explain...

  5. Anisotropic hydrodynamics and the early-thermalization puzzle

    CERN Document Server

    Florkowski, Wojciech

    2012-01-01

    The framework of anisotropic hydrodynamics is used in 3+1 dimensions to analyze behavior of matter produced in ultra-relativistic heavy-ion collisions. The model predictions for the hadronic transverse-momentum spectra, directed and elliptic flows, and the HBT radii are presented. We show that the effects of the initial anisotropy of pressure may be compensated by appropriate adjustment of the initial energy density. In this way, the final hadronic observables become insensitive to the early stage dynamics and the early thermalization puzzle may be circumvented.

  6. The Long Slow Death of the HBT Puzzle

    CERN Document Server

    Pratt, Scott

    2008-01-01

    Femtoscopic measurements at RHIC have been hailed as a source of insight into the bulk properties of QCD matter. However, hydrodynamic models, which have been successful in reproducing other observables have failed to satisfactorily explain femtoscopic two-particle correlation measurements. This failure has been labeled the "HBT puzzle". In this talk, I present correlations using a hybrid model composed of a viscous hydrodynamic module and a hadronic cascade. After incorporating early acceleration, viscosity and a stiffer equation of state, the extracted source sizes come much closer to experiment.

  7. Solving Solar Neutrino Puzzle via LMA MSW Conversion

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    We analyze the existing solar neutrino experiment data and show the allowed regions. The result from SNO's salt phase itself restricts quite a lot the allowed region's area. Reactor neutrinos play an important role in determining oscillation parameters. KamLAND gives decisive conclusion on the solution to the solar neutrino puzzle, in particular, the spectral distortion in the 766.3 Ty KamLAND data gives another new improvement in the constraint of solar MSW-LMA solutions. We confirm that at 99. 73% C.L. the high-LMA solution is excluded.

  8. A Dynamical Resolution of the Sigma Term Puzzle

    CERN Document Server

    Ball, R D; Tigg, J; Ball, Richard D.; Forte, Stefano; Tigg, Jason

    1994-01-01

    We propose a resolution of the puzzle posed by the discrepancy between the pion-nucleon sigma term inferred from pion-nucleon scattering, and that deduced from baryon mass splittings using the Zweig rule. We show that there is a significant hypercharge-dependent dynamical contribution to baryon masses, not hitherto included in the analysis, which may be estimated using the scale Ward identity, and computed by solution of the Schwinger-Dyson equation for the quark self-energy. We find that the discrepancy is completely resolved without the need for any Zweig rule violation.

  9. The puzzle of non-proliferation and disarmament; El puzzle de la No-Proliferacion y el Desarme (primera parte)

    Energy Technology Data Exchange (ETDEWEB)

    Ponga, J. de

    2011-07-01

    Since, in 1945, the World was aware of the devastating power of nuclear weapons, there have been many initiatives at international level to avoid nuclear weapon proliferation: the foundation of the IAEA, the NPT, the Safeguards Agreements, the Nuclear Weapon Free Zones, the treaties banning nuclear tests or the export control regime of the NSG, among others. This article aims to offer a general picture of all of them as pieces of a puzzle the purpose of which is not to allow gaps to non pacific uses of nuclear energy. (Author)

  10. An ecological examination of rapport using a dyadic puzzle task.

    Science.gov (United States)

    Grahe, Jon E; Sherman, Ryne A

    2007-10-01

    Previous studies have indicated that situational context impacts the rapport experience (e.g., F. J. Bernieri, J. S. Gillis, J. M. Davis, & J. E. Grahe, 1996; N. M. Puccinelli, L. Tickle-Degnen, & R. Rosenthal, 2003). The authors designed the present study to further document the behavioral and experiential predictors of dyadic rapport and to evaluate dyadic rapport experiences when contributions were required from both interactants. Participants (N = 60) were paired into dyads and instructed to complete children's puzzles. However, the dyadic members were restricted in how they could accomplish this task: Only one interactant was allowed to work on the puzzle and had to do so blindfolded, while the second interactant gave instructions. Results suggested that less attribution of responsibility to the worker and the instructor's experience of enjoyment and frustration were indicative of higher rapport. Other characteristics of dyads reporting higher dyadic rapport included difficulty completing the task and more communicative behavior. The results provide important information for the understanding of the dyadic experience of rapport.

  11. The puzzling unsolved mysteries of liquid water: Some recent progress

    Science.gov (United States)

    Stanley, H. E.; Kumar, P.; Xu, L.; Yan, Z.; Mazza, M. G.; Buldyrev, S. V.; Chen, S.-H.; Mallamace, F.

    2007-12-01

    Water is perhaps the most ubiquitous, and the most essential, of any molecule on earth. Indeed, it defies the imagination of even the most creative science fiction writer to picture what life would be like without water. Despite decades of research, however, water's puzzling properties are not understood and 63 anomalies that distinguish water from other liquids remain unsolved. We introduce some of these unsolved mysteries, and demonstrate recent progress in solving them. We present evidence from experiments and computer simulations supporting the hypothesis that water displays a special transition point (which is not unlike the “tipping point” immortalized by Malcolm Gladwell). The general idea is that when the liquid is near this “tipping point,” it suddenly separates into two distinct liquid phases. This concept of a new critical point is finding application to other liquids as well as water, such as silicon and silica. We also discuss related puzzles, such as the mysterious behavior of water near a protein.

  12. The King and Prisoner Puzzle: A Way of Introducing the Components of Logical Structures

    Science.gov (United States)

    Roh, Kyeong Hah; Lee, Yong Hah; Tanner, Austin

    2016-01-01

    The purpose of this paper is to provide issues related to student understanding of logical components that arise when solving word problems. We designed a logic problem called the King and Prisoner Puzzle--a linguistically simple, yet logically challenging problem. In this paper, we describe various student solutions to the puzzle and discuss the…

  13. Using the Tower of Hanoi Puzzle to Infuse Your Mathematics Classroom with Computer Science Concepts

    Science.gov (United States)

    Marzocchi, Alison S.

    2016-01-01

    This article suggests that logic puzzles, such as the well-known Tower of Hanoi puzzle, can be used to introduce computer science concepts to mathematics students of all ages. Mathematics teachers introduce their students to computer science concepts that are enacted spontaneously and subconsciously throughout the solution to the Tower of Hanoi…

  14. Crossword Puzzle Makes It Fun: Introduce Green Manufacturing in Wood Technology Courses

    Science.gov (United States)

    Iley, John L.; Hague, Doug

    2012-01-01

    Sustainable, or "green," manufacturing and its practices are becoming more and more a part of today's industry, including wood product manufacturing. This article provides introductory information on green manufacturing in wood technology and a crossword puzzle based on green manufacturing terms. The authors use the puzzle at the college level to…

  15. Natural Light Harvesting Systems: Unraveling the quantum puzzles

    CERN Document Server

    Thilagam, A

    2013-01-01

    In natural light harvesting systems, the sequential quantum events of photon absorption by specialized biological antenna complexes, charge separation, exciton formation and energy transfer to localized reaction centers culminates in the conversion of solar to chemical energy. A notable feature in these processes is the exceptionally high efficiencies (> 95 %) at which excitation is transferred from the illuminated protein complex site to the reaction centers. Such high exciton propagation rates within a system of interwoven biomolecular network structures, is yet to be replicated in artificial light harvesting complexes. A clue to unraveling the quantum puzzles of nature may lie in the observation of long lived coherences lasting several picoseconds in the electronic spectra of photosynthetic complexes, even in noisy environmental baths. A number of experimental and theoretical studies have been devoted to unlocking the links between quantum processes and information protocols, in the hope of finding answers...

  16. A Possible Resolution of the Strange Quark Polarization Puzzle ?

    CERN Document Server

    Leader, Elliot; Stamenov, Dimiter B

    2011-01-01

    We propose a possible resolution of the strange quark polarization puzzle i.e. of the contradiction between the negative polarized strange quark density obtained from analyses of inclusive DIS data and the positive values obtained from combined analyses of inclusive and semi-inclusive SIDIS data using de Florian et. al. (DSS) fragmentation functions. To this end the results of a new combined NLO QCD analysis of the polarized inclusive and semi-inclusive DIS data, using the Hirai et. al. (HKNS) fragmentation functions, are presented. It is demonstrated that the polarized strange quark density is very sensitive to the kaon fragmentation functions, and if the set of HKNS fragmentation functions is used, the polarized strange quark density from the combined analysis turns out to be negative and well consistent with values obtained from the pure DIS analyses.

  17. New analysis concerning the strange quark polarization puzzle

    CERN Document Server

    Leader, Elliot; Stamenov, Dimiter B

    2014-01-01

    The fact that analyses of semi-inclusive deep inelastic scattering suggest that the strange quark polarization $\\Delta s(x) + \\Delta \\bar{s}(x)$ is positive in the measured region of Bjorken x, whereas all analyses of inclusive deep inelastic scattering yield significantly negative values of this quantity, is known as the "strange quark polarization puzzle". We have re-analysed the world data on inclusive deep inelastic scattering, including the COMPASS 2010 proton data on the spin asymmetries, and for the first time, the new extremely precise JLab CLAS data on the proton and deuteron spin structure functions. Despite allowing, in our parametrization, for a possible sign change, our results confirm that the inclusive data yield significantly negative values for the strange quark polarization.

  18. The puzzling resilience of transnational organized criminal networks

    DEFF Research Database (Denmark)

    Leuprecht, Christian; Aulthouse, Andrew; Walther, Olivier

    2016-01-01

    Why is transnational organized crime so difficult to dismantle? While organized crime networks within states have received some attention, actual transnational operations have not. In this article, we study the transnational drug and gun trafficking operations of the Shower Posse, a violent...... international organized crime syndicate based in Jamaica, whose resilience proves particularly puzzling. We were curious to know whether there is any evidence that international borders have an effect on the structure of illicit networks that cross them. It turns out that transnational drug distribution...... networks such as the Shower Posse rely on a small number of brokers whose role is to connect otherwise distinct domestic markets. Due to the high transaction costs associated with developing and maintaining transnational movement, the role of such brokers appears particularly important in facilitating...

  19. The B-CP Puzzles in QCD Factorization

    CERN Document Server

    Cheng, Hai-Yang

    2010-01-01

    Within the framework of QCD factorization (QCDF), power corrections due to penguin annihilation can account for theobserved rates of penguin-dominated two-body decays of $B$ mesons and direct CP asymmetries $A_{CP}(K^-\\pi^+)$, $A_{CP}((K^{*-}\\pi^+)$, $A_{CP}((K^-\\rho^0)$ and $A_{CP}((\\pi^+\\pi^-)$. However, the predicted direct CP-violating effects in QCDF for $B^-\\to K^-\\pi^0,K^-\\eta,\\pi^-\\eta$ and $\\bar B^0\\to\\pi^0\\pi^0$ are wrong in signs when confronted with experiment. We consider two different types of power correction effects in order to resolve the CP puzzles and rate deficit problems with penguin-dominated two-body decays of $B$ mesons and color-suppressed tree-dominated $\\pi^0\\pi^0$ and $\\rho^0\\pi^0$ modes: penguin annihilation and soft corrections to the color-suppressed tree amplitude.

  20. The Jigsaw Puzzle of Digital Preservation — an Overview

    Directory of Open Access Journals (Sweden)

    Barbara Sierman

    2009-03-01

    Full Text Available Before the 22nd Annual Meeting of the Board of Directors of the Foundation CENL, Zagreb, September 24–27, 2008, the author presented a clear overview of the latest developments in digital preservation in a European context. She dealt with organisational aspects, the digital objects themselves, and the effects of international European collaboration. She calls on European organisations such as the Alliance for Permanent Access to sustain the results of temporary projects like PLANETS and thereby bring the pieces of the digital preservation puzzle together. This paper is being published in preparation of the workshop on Curating Research: e-Merging New Roles and Responsibilities in the European Landscape, which is being co-organised by LIBER on 17 April 2009 at the Koninklijke Bibliotheek in The Hague.

  1. 200 more puzzling physics problems with hints and solutions

    CERN Document Server

    Gnädig, Péter; Vigh, Máté

    2016-01-01

    Like its predecessor, 200 Puzzling Physics Problems, this book is aimed at strengthening students' grasp of the laws of physics by applying them to situations that are practical, and to problems that yield more easily to intuitive insight than to brute-force methods and complex mathematics. The problems are chosen almost exclusively from classical, non-quantum physics, but are no easier for that. They are intriguingly posed in accessible non-technical language, and require readers to select an appropriate analysis framework and decide which branches of physics are involved. The general level of sophistication needed is that of the exceptional school student, the good undergraduate, or the competent graduate student; some physics professors may find some of the more difficult questions challenging. By contrast, the mathematical demands are relatively minimal, and seldom go beyond elementary calculus. This further book of physics problems is not only instructive and challenging, but also enjoyable.

  2. SybilControl: Practical Sybil Defense with Computational Puzzles

    CERN Document Server

    Li, Frank; Caesar, Matthew; Borisov, Nikita

    2012-01-01

    Many distributed systems are subject to the Sybil attack, where an adversary subverts system operation by emulating behavior of multiple distinct nodes. Most recent work to address this problem leverages social networks to establish trust relationships between users. However, the use of social networks is not appropriate in all systems, as they can be subverted by social engineering techniques, require nodes in a P2P network to maintain and be aware of social network information, and may require overly optimistic assumptions about the fast-mixing nature of social links. This paper explores an alternate approach. We present SybilControl, a novel, decentralized scheme for controlling the extent of Sybil attacks. SybilControl is an admission control mechanism for nodes in a distributed system that requires them to periodically solve computational puzzles. SybilControl consists of a distributed protocol to allow nodes to collectively verify the computational work of other nodes, and mechanisms to prevent the mali...

  3. Interfacial depinning transitions in disordered media: revisiting an old puzzle

    Science.gov (United States)

    Moglia, Belén; Albano, Ezequiel V.; Villegas, Pablo; Muñoz, Miguel A.

    2014-10-01

    Interfaces advancing through random media represent a number of different problems in physics, biology and other disciplines. Here, we study the pinning/depinning transition of the prototypical non-equilibrium interfacial model, i.e. the Kardar-Parisi-Zhang equation, advancing in a disordered medium. We analyze separately the cases of positive and negative non-linearity coefficients, which are believed to exhibit qualitatively different behavior: the positive case shows a continuous transition that can be related to directed-percolation-depinning while in the negative case there is a discontinuous transition and faceted interfaces appear. Some studies have argued from different perspectives that both cases share the same universal behavior. Here, by using a number of computational and scaling techniques we shed light on this puzzling situation and conclude that the two cases are intrinsically different.

  4. A Jigsaw Puzzle Layer Cake of Spatial Data

    Science.gov (United States)

    Ma, Xiaogang; Fox, Peter

    2014-05-01

    The Infrastructure for Spatial Information in Europe (INSPIRE; http://inspire.jrc.ec.europa.eu) is a European Union (EU) directive that aims to provide a legal framework to share environmental spatial data among public sector organizations across Europe and to facilitate public access to data. To meet these goals, INSPIRE's organization is analogous to a layer cake in which each layer is composed of interlocking pieces of a jigsaw puzzle. The metaphor, although mixed, is apt (see additional supporting information in the online version of this article), and as researchers outside the program, we offer our perspective on how INSPIRE may address challenges raised by the variety of data themes and the wide coverage of collaborators.

  5. Diagnosing the Cause of Scientific Standstill, Unravelling the Needham Puzzle

    Institute of Scientific and Technical Information of China (English)

    刘迎秋; 刘春江

    2007-01-01

    There are diverse opinions about how to solve the Needham Puzzle. Such opinions or schools of thought can be roughly classified into three theories of a) geographical conditions, b) empirical trial and error, and c) private property rights. Although each school of thought makes sense, they all fail to fully uncover the main reason why, in modern history, China lagged behind western countries in the development of science and technology. In our opinion, the correct solution is to draw on historical experiences, integrate all schools of thought, proceed with an emphasis on the definition and protection of property rights, boost government investment in basic scientific research, strengthen government service functionality, actively develop NGOs, and open more widely to the outside world, with a view of pushing forward China’s scientific and technological innovation and accelerating the pace of China’s modernization.

  6. Induced Hyperon-Nucleon-Nucleon Interactions and the Hyperon Puzzle

    CERN Document Server

    Wirth, Roland

    2016-01-01

    We present the first ab initio calculations for $p$-shell hypernuclei including hyperon-nucleon-nucleon (YNN) contributions induced by a Similarity Renormalization Group transformation of the initial hyperon-nucleon interaction. The transformation including the YNN terms conserves the spectrum of the Hamiltonian while drastically improving model-space convergence of the Importance-Truncated No-Core Shell Model, allowing a precise extraction of binding and excitation energies. Results using a hyperon-nucleon interaction at leading order in chiral effective field theory for lower- to mid-$p$-shell hypernuclei show a good reproduction of experimental excitation energies while hyperon binding energies are typically overestimated. The induced YNN contributions are strongly repulsive and we show that they are related to a decoupling of the $\\Sigma$ hyperons from the hypernuclear system, i.e., a suppression of the $\\Lambda$-$\\Sigma$ conversion terms in the Hamiltonian. This is linked to the so-called hyperon puzzle ...

  7. A Resolution of the Purchasing Power Parity Puzzle: Imperfect Knowledge and Long Swings

    DEFF Research Database (Denmark)

    Frydman, Roman; Goldberg, Michael D.; Johansen, Søren;

    2009-01-01

    Asset prices undergo long swings that revolve around benchmark levels. In currency markets, fluctuations involve real exchange rates that are highly persistent and that move in near-parallel fashion with nominal rates. The inability to explain these two regularities with one model has been called...... the "purchasing power parity puzzle." In this paper, we trace the puzzle to exchange rate modelers' use of the "Rational Expectations Hypothesis." We show that once imperfect knowledge is recognized, a monetary model is able to account for the puzzle, as well as other salient features of the data, including...

  8. Equity-premium puzzle: evidence from Brazilian data

    Directory of Open Access Journals (Sweden)

    Rubens Penha Cysne

    2006-06-01

    Full Text Available This paper uses 1992:1-2004:2 quarterly data and two different methods (approximation under lognormality and calibration to evaluate the existence of an equity-premium puzzle in Brazil. In contrast with some previous works in the Brazilian literature, I conclude that the model used by Mehra and Prescott (1985, either with additive or recursive preferences, is not able to satisfactorily rationalize the equity premium observed in the Brazilian data. The second contribution of the paper is calling the attention to the fact that the utility function calculated under the discrete-state approximation may not exist if the data (as it is the case with Brazilian time series implies the existence of states in which high negative rates of consumption growth are attained with relatively high probability. This fact is particularly important when the researcher tries to work with high risk-aversion parameters in order to generate high risk premia.Este trabalho usa dados brasileiros do período 1992:1-2004:2 e dois diferentes métodos (aproximação sob a hipótese de lognormalidade e calibração para avaliar a existência de um "equity-premium puzzle" no Brasil. Em contraste com alguns trabalhos prévios da literatura nacional, conclui-se que o modelo usado por Mehra and Prescott (1985, seja com preferências aditivas ou recursivas, não é capaz de gerar o prêmio de risco observado na economia brasileira. A segunda contribuição do trabalho é chamar a atenção para o fato de que a função utilidade calculada sob a hipótese de aproximação discreta do espaço de estados pode não existir se os dados (como é o caso no Brasil implicarem a existência de estados nos quais taxas altamente negativas de crescimento do consumo são alcançadas com probabilidade demasiado elevadas. Este fato é particularmente importante quando se tenta utilizar parâmetros de aversão ao risco altos o suficiente para gerar o prêmio de risco inerente ao caso brasileiro.

  9. Satisfiability Parsimoniously Reduces to the Tantrix(TM) Rotation Puzzle Problem

    CERN Document Server

    Baumeister, Dorothea

    2007-01-01

    Holzer and Holzer (Discrete Applied Mathematics 144(3):345--358, 2004) proved that the Tantrix(TM) rotation puzzle problem is NP-complete. They also showed that for infinite rotation puzzles, this problem becomes undecidable. We study the counting version and the unique version of this problem. We prove that the satisfiability problem parsimoniously reduces to the Tantrix(TM) rotation puzzle problem. In particular, this reduction preserves the uniqueness of the solution, which implies that the unique Tantrix(TM) rotation puzzle problem is as hard as the unique satisfiability problem, and so is DP-complete under polynomial-time randomized reductions, where DP is the second level of the boolean hierarchy over NP.

  10. A Play on Words: Using Cognitive Computing as a Basis for AI Solvers in Word Puzzles

    Science.gov (United States)

    Manzini, Thomas; Ellis, Simon; Hendler, James

    2015-12-01

    In this paper we offer a model, drawing inspiration from human cognition and based upon the pipeline developed for IBM's Watson, which solves clues in a type of word puzzle called syllacrostics. We briefly discuss its situation with respect to the greater field of artificial general intelligence (AGI) and how this process and model might be applied to other types of word puzzles. We present an overview of a system that has been developed to solve syllacrostics.

  11. Monetary Policy Shocks in a Small Open Economy: Assessing the 'Puzzles' of Monetary Policy by SVAR

    OpenAIRE

    Ajluni, Jarir

    2005-01-01

    The paper examines the effects of monetary policy shocks and its puzzles on a small open economy using quarterly Korean data by applying a theoretically motivated Structural VAR, with the objective of introducing empirical evidence that investigates the magnitude and persistence of monetary policy using impulse response function analysis. There is some evidence on the occurrences of monetary policy puzzles confirming previous outcomes in the literature, results suggest that domestic monetary ...

  12. Graphene spintronics: puzzling controversies and challenges for spin manipulation

    Science.gov (United States)

    Roche, Stephan; Valenzuela, Sergio O.

    2014-03-01

    This article presents the current puzzling controversy between theory and experimental results concerning the mechanisms leading to spin relaxation in graphene-based materials. On the experimental side, it is surprising that regardless of the quality of the graphene monolayer, which is characterized by the carrier mobility, the typical Hanle precession measurements yield spin diffusion times (τs) in the order of τs ˜ 0.1-1 ns (at low temperatures), which is several orders of magnitude below the theoretical estimates based on the expected low intrinsic spin-orbit coupling in graphene. The results are weakly dependent on whether graphene is deposited onto SiO2 or boron-nitride substrates or is suspended, with the mobility spanning 3 orders of magnitude. On the other hand, extraction form two-terminal magnetoresistance measurements, accounting for contact effects results in τs ˜ 0.1 µs, and corresponding diffusion lengths of about 100 µm up to room temperature. Such discrepancy jeopardizes further progress towards spin manipulation on a lateral graphene two-dimensional platform. After a presentation of basic concepts, we here discuss state-of-the-art literature and the limits of all known approaches to describe spin transport in massless-Dirac fermions, in which the effects of strong local spin-orbit coupling ceases to be accessible with perturbative approaches. We focus on the limits of conventional views of spin transport in graphene and offer novel perspectives for further progress.

  13. Mammary gland stem cells: More puzzles than explanations

    Indian Academy of Sciences (India)

    Suneesh Kaimala; Suneesh Kaimala; Satish Kumar

    2012-06-01

    Mammary gland stem cells (MaSC) have not been identified in spite of extensive research spanning over several decades. This has been primarily due to the complexity of mammary gland structure and its development, cell heterogeneity in the mammary gland and the insufficient knowledge about MaSC markers. At present, Lin–CD29hiCD49fhiCD24+/modSca-1– cells of the mammary gland have been reported to be enriched with MaSCs. We suggest that the inclusion of stem cell markers like Oct4, Sox2, Nanog and the mammary gland differentiation marker BRCA-1 may further narrow down the search for MaSCs. In addition, we have discussed some of the other unresolved puzzles on the mammary gland stem cells, such as their similarities and/or differences with mammary cancer stem cells, use of milk as source of mammary stem cells and the possibility of in vitro differentiation of embryonic stem (ES) cells into functional mammary gland structures in this review. Nevertheless, it is the lack of identity for a MaSC that is curtailing the advances in some of the above and other related areas.

  14. Is the proton radius puzzle evidence of extra dimensions?

    Energy Technology Data Exchange (ETDEWEB)

    Dahia, F.; Lemos, A.S. [Universidade Federal da Paraiba, Department of Physics, Joao Pessoa, PB (Brazil)

    2016-08-15

    The proton charge radius inferred from muonic hydrogen spectroscopy is not compatible with the previous value given by CODATA-2010, which, on its turn, essentially relies on measurements of the electron-proton interaction. The proton's new size was extracted from the 2S-2P Lamb shift in the muonic hydrogen, which showed an energy excess of 0.3 meV in comparison to the theoretical prediction, evaluated with the CODATA radius. Higher-dimensional gravity is a candidate to explain this discrepancy, since the muon-proton gravitational interaction is stronger than the electron-proton interaction and, in the context of braneworld models, the gravitational potential can be hugely amplified in short distances when compared to the Newtonian potential. Motivated by these ideas, we study a muonic hydrogen confined in a thick brane. We show that the muon-proton gravitational interaction modified by extra dimensions can provide the additional separation of 0.3 meV between the 2S and 2P states. In this scenario, the gravitational energy depends on the higher-dimensional Planck mass and indirectly on the brane thickness. Studying the behavior of the gravitational energy with respect to the brane thickness in a realistic range, we find constraints for the fundamental Planck mass that solve the proton radius puzzle and are consistent with previous experimental bounds. (orig.)

  15. Resolution of the B -> pi pi, pi K puzzles

    CERN Document Server

    Li, Hsiang-nan

    2009-01-01

    We show that there exist uncanceled soft divergences in the k_T factorization for nonfactorizable amplitudes of two-body nonleptonic B meson decays, similar to those identified in hadron-hadron collisions. Viewing the special role of the pion as a q qbar bound state and as a pseudo Nambu-Goldstone boson, we associate a soft factor with it in the perturbative QCD formalism. This soft factor enhances the nonfactorizable color-suppressed tree amplitudes, such that the branching ratios B(pi^0 pi^0) and B(pi^0 rho^0) are increased under the constraint of the B(rho^0 rho^0) data, the difference between the direct CP asymmetries A_{CP}(pi^\\mp K^\\pm) and A_{CP}(pi^0 K^\\pm) is enlarged, and the mixing-induced CP asymmetry S_{pi^0 K_S} is reduced. That is, the known pi pi and pi K puzzles can be resolved simultaneously.

  16. Herschel unveils a puzzling uniformity of distant dusty galaxies

    CERN Document Server

    Elbaz, D; Magnelli, B; Daddi, E; Aussel, H; Altieri, B; Amblard, A; Andreani, P; Arumugam, V; Auld, R; Babbedge, T; Berta, S; Blain, A; Bock, J; Bongiovanni, A; Boselli, A; Buat, V; Burgarella, D; Castro-Rodriguez, N; Cava, A; Cepa, J; Chanial, P; Chary, R -R; Cimatti, A; Clements, D L; Conley, A; Conversi, L; Cooray, A; Dickinson, M; Dominguez, H; Dowell, C D; Dunlop, J S; Dwek, E; Eales, S; Farrah, D; Schreiber, N Forster; Fox, M; Franceschini, A; Gear, W; Genzel, R; Glenn, J; Griffin, M; Gruppioni, C; Halpern, M; Hatziminaoglou, E; Ibar, E; Isaak, K; Ivison, R J; Lagache, G; Le Borgne, D; Le Floc'h, E; Levenson, L; Lu, N; Lutz, D; Madden, S; Maffei, B; Magdis, G; Mainetti, G; Maiolino, R; Marchetti, L; Mortier, A M J; Nguyen, H T; Nordon, R; O'Halloran, B; Okumura, K; Oliver, S J; Omont, A; Page, M J; Panuzzo, P; Papageorgiou, A; Pearson, C P; Fournon, I Perez; Garcıa, A M Perez; Poglitsch, A; Pohlen, M; Popesso, P; Pozzi, F; Rawlings, J I; Rigopoulou, D; Riguccini, L; Rizzo, D; Rodighiero, G; Roseboom, I G; Rowan-Robinson, M; Saintonge, A; Sanchez-Portal, M; Santini, P; Sauvage, M; Schulz, B; Scott, Douglas; Seymour, N; Shao, L; Shupe, D L; Smith, A J; Stevens, J A; Sturm, E; Symeonidis, M; Tacconi, L; Trichas, M; Tugwell, K E; Vaccari, M; Valtchanov, I; Vieira, J; Vigroux, L; Wang, L; Ward, R; Wright, G; Xu, C K; Zemcov, M

    2010-01-01

    The Herschel Space Observatory enables us to accurately measure the bolometric output of starburst galaxies and active galactic nuclei (AGN) by directly sampling the peak of their far-infrared (IR) emission. Here we examine whether the spectral energy distribution (SED) and dust temperature of galaxies have strongly evolved since z~2.5. We use Herschel deep extragalactic surveys from 100 to 500um to compute total IR luminosities in galaxies down to the faintest levels, using PACS and SPIRE in the GOODS-North field (PEP and HerMES key programs). We show that measurements in the SPIRE bands can be used below the statistical confusion limit if information at higher spatial resolution is used to identify isolated galaxies whose flux is not boosted by bright neighbors. Below z~1.5, mid-IR extrapolations are correct for star-forming galaxies with a dispersion of only 40% (0.15dex), therefore similar to z~0 galaxies. This narrow distribution is puzzling when considering the range of physical processes that could hav...

  17. Effect of a puzzle on the process of students' learning about cardiac physiology.

    Science.gov (United States)

    Cardozo, Lais Tono; Miranda, Aline Soares; Moura, Maria José Costa Sampaio; Marcondes, Fernanda Klein

    2016-09-01

    The aim of the present study was to evaluate the effects of using a puzzle to learn about cardiac physiology. Students were divided into control and game groups. In class 1, the control group had a 2-h theoretical class about cardiac physiology, including a detailed description of the phases of the cardiac cycle, whereas the game group had a 50-min theoretical class without the description of the cardiac cycle. In class 2, the control group did an assessment exercise before an activity with the cardiac puzzle and the game group answered questions after the above-mentioned activity. While solving the puzzle, the students had to describe the cardiac cycle by relating the concepts of heart morphology and physiology. To evaluate short-term learning, the number of wrong answers and grades in the assessment exercise were compared between the control and game groups. To evaluate medium-term learning, we compared the grades obtained by students of the control and game groups in questions about cardiac physiology that formed part of the academic exam. In the assessment exercise, the game group presented a lower number of errors and higher score compared with the control group. In the academic exam, applied after both groups had used the puzzle, there was no difference in the scores obtained by the control and game groups in questions about cardiac physiology. These results showed a positive effect of the puzzle on students' learning about cardiac physiology compared with those not using the puzzle.

  18. Hyperon puzzle, hadron-quark crossover and massive neutron stars

    Energy Technology Data Exchange (ETDEWEB)

    Masuda, Kota [The University of Tokyo, Department of Physics, Tokyo (Japan); Nishina Center, RIKEN, Theoretical Research Division, Wako (Japan); Hatsuda, Tetsuo [Nishina Center, RIKEN, Theoretical Research Division, Wako (Japan); The University of Tokyo, Kavli IPMU (WPI), Chiba (Japan); Takatsuka, Tatsuyuki [Nishina Center, RIKEN, Theoretical Research Division, Wako (Japan)

    2016-03-15

    Bulk properties of cold and hot neutron stars are studied on the basis of the hadron-quark crossover picture where a smooth transition from the hadronic phase to the quark phase takes place at finite baryon density. By using a phenomenological equation of state (EOS) ''CRover'', which interpolates the two phases at around 3 times the nuclear matter density (ρ{sub 0}), it is found that the cold NSs with the gravitational mass larger than 2M {sub CircleDot} can be sustained. This is in sharp contrast to the case of the first-order hadron-quark transition. The radii of the cold NSs with the CRover EOS are in the narrow range (12.5 ± 0.5) km which is insensitive to the NS masses. Due to the stiffening of the EOS induced by the hadron-quark crossover, the central density of the NSs is at most 4 ρ{sub 0} and the hyperon-mixing barely occurs inside the NS core. This constitutes a solution of the long-standing hyperon puzzle. The effect of color superconductivity (CSC) on the NS structures is also examined with the hadron-quark crossover. For the typical strength of the diquark attraction, a slight softening of the EOS due to two-flavor CSC (2SC) takes place and the maximum mass is reduced by about 0.2M {sub CircleDot}. The CRover EOS is generalized to the supernova matter at finite temperature to describe the hot NSs at birth. The hadron-quark crossover is found to decrease the central temperature of the hot NSs under isentropic condition. The gravitational energy release and the spin-up rate during the contraction from the hot NS to the cold NS are also estimated. (orig.)

  19. Emergence of Life on Earth: A Physicochemical Jigsaw Puzzle.

    Science.gov (United States)

    Spitzer, Jan

    2017-01-01

    We review physicochemical factors and processes that describe how cellular life can emerge from prebiotic chemical matter; they are: (1) prebiotic Earth is a multicomponent and multiphase reservoir of chemical compounds, to which (2) Earth-Moon rotations deliver two kinds of regular cycling energies: diurnal electromagnetic radiation and seawater tides. (3) Emerging colloidal phases cyclically nucleate and agglomerate in seawater and consolidate as geochemical sediments in tidal zones, creating a matrix of microspaces. (4) Some microspaces persist and retain memory from past cycles, and others re-dissolve and re-disperse back into the Earth's chemical reservoir. (5) Proto-metabolites and proto-biopolymers coevolve with and within persisting microspaces, where (6) Macromolecular crowding and other non-covalent molecular forces govern the evolution of hydrophilic, hydrophobic, and charged molecular surfaces. (7) The matrices of microspaces evolve into proto-biofilms of progenotes with rudimentary but evolving replication, transcription, and translation, enclosed in unstable cell envelopes. (8) Stabilization of cell envelopes 'crystallizes' bacteria-like genetics and metabolism with low horizontal gene transfer-life 'as we know it.' These factors and processes constitute the 'working pieces' of the jigsaw puzzle of life's emergence. They extend the concept of progenotes as the first proto-cellular life, connected backward in time to the cycling chemistries of the Earth-Moon planetary system, and forward to the ancient cell cycle of first bacteria-like organisms. Supra-macromolecular models of 'compartments first' are preferred: they facilitate macromolecular crowding-a key abiotic/biotic transition toward living states. Evolutionary models of metabolism or genetics 'first' could not have evolved in unconfined and uncrowded environments because of the diffusional drift to disorder mandated by the second law of thermodynamics.

  20. Composite Operator Method Analysis of the Underdoped Cuprates Puzzle

    Directory of Open Access Journals (Sweden)

    Adolfo Avella

    2014-01-01

    Full Text Available The microscopical analysis of the unconventional and puzzling physics of the underdoped cuprates, as carried out lately by means of the composite operator method (COM applied to the 2D Hubbard model, is reviewed and systematized. The 2D Hubbard model has been adopted as it has been considered the minimal model capable of describing the most peculiar features of cuprates held responsible for their anomalous behavior. COM is designed to endorse, since its foundation, the systematic emergence in any SCS of new elementary excitations described by composite operators obeying noncanonical algebras. In this case (underdoped cuprates—2D Hubbard model, the residual interactions—beyond a 2-pole approximation—between the new elementary electronic excitations, dictated by the strong local Coulomb repulsion and well described by the two Hubbard composite operators, have been treated within the noncrossing approximation. Given this recipe and exploiting the few unknowns to enforce the Pauli principle content in the solution, it is possible to qualitatively describe some of the anomalous features of high-Tc cuprate superconductors such as large versus small Fermi surface dichotomy, Fermi surface deconstruction (appearance of Fermi arcs, nodal versus antinodal physics, pseudogap(s, and kinks in the electronic dispersion. The resulting scenario envisages a smooth crossover between an ordinary weakly interacting metal sustaining weak, short-range antiferromagnetic correlations in the overdoped regime to an unconventional poor metal characterized by very strong, long-but-finite-range antiferromagnetic correlations leading to momentum-selective non-Fermi liquid features as well as to the opening of a pseudogap and to the striking differences between the nodal and the antinodal dynamics in the underdoped regime.

  1. Usefulness of Crossword Puzzles in Helping First-Year BVSc Students Learn Veterinary Terminology.

    Science.gov (United States)

    Abuelo, Angel; Castillo, Cristina; May, Stephen A

    2016-01-01

    Appropriate terminology is essential for successful communication among health professionals. However, students have traditionally been encouraged to learn terminology by rote memorization and recall, strategies that students try to avoid. The use of crossword puzzles as a learning tool has been evaluated in other education disciplines, but not for terminology related to veterinary science. Hence, the objective of this study was to test whether crossword puzzles might be an effective aid to learning veterinary terminology. Forty-two first-year students enrolled in a Bachelor of Veterinary Science program were randomly divided into two groups and their previous knowledge of veterinary terms tested. One group received a list of 30 terms with their definitions. The other group received the same list plus six specially designed puzzles incorporating these 30 terms. After 50 minutes, both groups completed a post-intervention test and the results were compared statistically. The results showed that the students using the crossword puzzles performed better in the post-intervention test, correctly retaining more terms than the students using only rote learning. In addition, qualitative data, gathered through an electronic survey and focus group discussions, revealed a positive attitude among students toward the use of crossword puzzles.

  2. A MULTISET APPROACH FOR RECOGNITION OF HANDWRITTEN CHARACTERS USING PUZZLE PIECES

    Directory of Open Access Journals (Sweden)

    Ashlin Deepa R.N

    2012-07-01

    Full Text Available Image pattern matching is one of the most widely used techniques in character recognition. A pattern is the description of an object. Although a large number of papers have been reported on handwritten character recognition, it is still a very challenging problem. Recognition of characters is based on pattern classification. In this paper a hybrid approach is proposed using fuzzy technique and multiset comparison to recognize handwritten characters. Fuzzy technique is used to measure the variations in the features of handwritten numerals to form strings of character. Features are selected from the preprocessed image and the feature is labeled using fuzzy logic. Strings of a character are formed from these labeled primitives. Each string is divided into a multiset of puzzle pieces by repeatedly applying a mask which is comprised of all ones. The string is padded with anchors at the beginning and end. The mask is placed over the string, beginning at a certain character, and reading off all characters corresponding to 1 bit in the mask, thus producing one puzzle piece. To divide a string into multiset of puzzle pieces, the mask is applied at all shifts in the string starting at each character. Thus for each prototype character, we associate a multiset of puzzle pieces, which form the database. The multiset of puzzle pieces of an unknown character is constructed and compared with the same in the database, leading to the identification of the unknown character.

  3. Puzzle Imaging: Using Large-Scale Dimensionality Reduction Algorithms for Localization.

    Directory of Open Access Journals (Sweden)

    Joshua I Glaser

    Full Text Available Current high-resolution imaging techniques require an intact sample that preserves spatial relationships. We here present a novel approach, "puzzle imaging," that allows imaging a spatially scrambled sample. This technique takes many spatially disordered samples, and then pieces them back together using local properties embedded within the sample. We show that puzzle imaging can efficiently produce high-resolution images using dimensionality reduction algorithms. We demonstrate the theoretical capabilities of puzzle imaging in three biological scenarios, showing that (1 relatively precise 3-dimensional brain imaging is possible; (2 the physical structure of a neural network can often be recovered based only on the neural connectivity matrix; and (3 a chemical map could be reproduced using bacteria with chemosensitive DNA and conjugative transfer. The ability to reconstruct scrambled images promises to enable imaging based on DNA sequencing of homogenized tissue samples.

  4. RNA-Puzzles Round III: 3D RNA structure prediction of five riboswitches and one ribozyme.

    Science.gov (United States)

    Miao, Zhichao; Adamiak, Ryszard W; Antczak, Maciej; Batey, Robert T; Becka, Alexander J; Biesiada, Marcin; Boniecki, Michał J; Bujnicki, Janusz; Chen, Shi-Jie; Cheng, Clarence Yu; Chou, Fang-Chieh; Ferré-D'Amaré, Adrian R; Das, Rhiju; Dawson, Wayne K; Feng, Ding; Dokholyan, Nikolay V; Dunin-Horkawicz, Stanisław; Geniesse, Caleb; Kappel, Kalli; Kladwang, Wipapat; Krokhotin, Andrey; Łach, Grzegorz E; Major, François; Mann, Thomas H; Magnus, Marcin; Pachulska-Wieczorek, Katarzyna; Patel, Dinshaw J; Piccirilli, Joseph A; Popenda, Mariusz; Purzycka, Katarzyna J; Ren, Aiming; Rice, Greggory M; Santalucia, John; Sarzynska, Joanna; Szachniuk, Marta; Tandon, Arpit; Trausch, Jeremiah J; Tian, Siqi; Wang, Jian; Weeks, Kevin M; Williams, Benfeard; Xiao, Yi; Xu, Xiaojun; Zhang, Dong; Zok, Tomasz; Westhof, Eric

    2017-01-30

    RNA-Puzzles is a collective experiment in blind 3D RNA structure prediction. We report here a third round of RNA-Puzzles. Five puzzles, 4, 8, 12, 13, 14, all structures of riboswitch aptamers and puzzle 7, a ribozyme structure, are included in this round of the experiment. The riboswitch structures include biological binding sites for small molecules (S-adenosyl methionine, cyclic diadenosine monophosphate, 5-amino 4-imidazole carboxamide riboside 5'-triphosphate, glutamine) and proteins (YbxF) and one set describes large conformational changes between ligand-free and ligand-bound states; the Varkud satellite ribozyme is the most recently solved structure of a known large ribozyme. All the puzzles have established biological functions and require structural understanding to appreciate their molecular mechanisms. Through the use of fast-track experimental data, including multidimensional chemical mapping, and accurate prediction of RNA secondary structure, a large portion of the contacts in 3D have been predicted correctly leading to similar topologies for the top ranking predictions. Template-based and homology-derived predictions could predict structures to particularly high accuracies. However, achieving biological insights from de novo prediction of RNA 3D structures still depends on the size and complexity of the RNA. Blind computational predictions of RNA structures already appear to provide useful structural information in many cases. Similar to the previous RNA-Puzzles Round II experiment, the prediction of non-Watson-Crick interactions and the observed high atomic clash scores reveal notable need for algorithm of improvement. All prediction models and assessment results are available at http://ahsoka.u-strasbg.fr/rnapuzzles/.

  5. Using the Tower of Hanoi puzzle to infuse your mathematics classroom with computer science concepts

    Science.gov (United States)

    Marzocchi, Alison S.

    2016-07-01

    This article suggests that logic puzzles, such as the well-known Tower of Hanoi puzzle, can be used to introduce computer science concepts to mathematics students of all ages. Mathematics teachers introduce their students to computer science concepts that are enacted spontaneously and subconsciously throughout the solution to the Tower of Hanoi puzzle. These concepts include, but are not limited to, conditionals, iteration, and recursion. Lessons, such as the one proposed in this article, are easily implementable in mathematics classrooms and extracurricular programmes as they are good candidates for 'drop in' lessons that do not need to fit into any particular place in the typical curriculum sequence. As an example for readers, the author describes how she used the puzzle in her own Number Sense and Logic course during the federally funded Upward Bound Math/Science summer programme for college-intending low-income high school students. The article explains each computer science term with real-life and mathematical examples, applies each term to the Tower of Hanoi puzzle solution, and describes how students connected the terms to their own solutions of the puzzle. It is timely and important to expose mathematics students to computer science concepts. Given the rate at which technology is currently advancing, and our increased dependence on technology in our daily lives, it has become more important than ever for children to be exposed to computer science. Yet, despite the importance of exposing today's children to computer science, many children are not given adequate opportunity to learn computer science in schools. In the United States, for example, most students finish high school without ever taking a computing course. Mathematics lessons, such as the one described in this article, can help to make computer science more accessible to students who may have otherwise had little opportunity to be introduced to these increasingly important concepts.

  6. Does The Price Puzzle Exist in Colombia? Empirical Evidence and Policy Implications

    Directory of Open Access Journals (Sweden)

    Blen Solomon

    2006-04-01

    Full Text Available The price puzzle has been the focus of many studies, however, most of these studies have focused on developed economies and especially on the U.S. Owing to this tendency; we do not know if there is existence of a price puzzle in developing economies. This is an important topic of research as it facilitates the understanding on the different channels of monetary policy. It also helps our understanding regarding monetary policy effectiveness and in the context of the Colombian economy, this is a main issue as the basic long-term target of Colombia’s monetary policy is price stability. This study investigates the existence of the price puzzle for the period 1980:5-2003:12 in Colombia by using Vector Error Correction Model (VECM. Since the sample period of study is not characterized with a uniform monetary policy regime, following Balke and Emery (1994 we divide our sample period according to existent structural breaks. We test for the price puzzle by dividing our sample into pre-1991 period (before inflation targeting started and during inflation targeting period. We employ impulse response functions as our main tolos to investigate the price puzzle. The impulse response functions show that during both the pre-1991 and post 1991 periods, prices don’t rise in response to positive shocks in short term interest rates. Therefore we conclude that Colombia does not exhibit the price puzzle. In fact, during both periods as well as the whole sample period, prices are not responsive to short-term interest rate shocks. The unresponsiveness of prices to positive interest rate shocks is not expected since we would anticipate prices to decrease due to a positive interest rate shock

  7. Heavy quark dynamics in the QGP: Towards a solution of the RAA and ν2 puzzle

    Directory of Open Access Journals (Sweden)

    Scardina F.

    2016-01-01

    Full Text Available The two key observables related to heavy quarks that have been measured in experiments are the nuclear suppression factor RAA and the elliptic flow ν2. The simultaneous reproduction of these two observables is a puzzle which have challenged all the existing models. We discuss two ingredients responsible for addressing a large part of such a puzzle: the temperature dependence of the energy loss and the full solution of the Boltzmann collision integral for the scattering between the heavy quarks and the particle of the bulk.

  8. Utility of Self-Made Crossword Puzzles as an Active Learning Method to Study Biochemistry in Undergraduate Education

    Science.gov (United States)

    Coticone, Sulekha Rao

    2013-01-01

    To incorporate an active learning component in a one-semester biochemistry course, students were asked to create crossword puzzles using key concepts. Student observations on the use of self-made crossword puzzles as an active-learning instructional tool were collected using a 5-point Likert survey at the end of the semester. A majority of the…

  9. Random Tree-Puzzle leads to the Yule-Harding distribution.

    Science.gov (United States)

    Vinh, Le Sy; Fuehrer, Andrea; von Haeseler, Arndt

    2011-02-01

    Approaches to reconstruct phylogenies abound and are widely used in the study of molecular evolution. Partially through extensive simulations, we are beginning to understand the potential pitfalls as well as the advantages of different methods. However, little work has been done on possible biases introduced by the methods if the input data are random and do not carry any phylogenetic signal. Although Tree-Puzzle (Strimmer K, von Haeseler A. 1996. Quartet puzzling: a quartet maximum-likelihood method for reconstructing tree topologies. Mol Biol Evol. 13:964-969; Schmidt HA, Strimmer K, Vingron M, von Haeseler A. 2002. Tree-Puzzle: maximum likelihood phylogenetic analysis using quartets and parallel computing. Bioinformatics 18:502-504) has become common in phylogenetics, the resulting distribution of labeled unrooted bifurcating trees when data do not carry any phylogenetic signal has not been investigated. Our note shows that the distribution converges to the well-known Yule-Harding distribution. However, the bias of the Yule-Harding distribution will be diminished by a tiny amount of phylogenetic information. maximum likelihood, phylogenetic reconstruction, Tree-Puzzle, tree distribution, Yule-Harding distribution.

  10. On the Puzzle of Long and Short Gamma-Ray Bursts

    CERN Document Server

    Shao, Lang; Dai, Zi-Gao; Jin, Zhi-Ping; Yan, Jing-Zhi; Wei, Da-Ming

    2014-01-01

    In this paper we give a brief review of our recent studies on the long and short gamma-ray bursts (GRBs) detected Swift, in an effort to understand the puzzle of classifying GRBs. We consider that it is still an appealing conjecture that both long and short GRBs are drawn from the same parent sample by observational biases.

  11. Puzzle task ERP response: time-frequency and source localization analysis

    Science.gov (United States)

    Almurshedi, Ahmed; Ismail, Abd Khamim

    2015-01-01

    Perceptual decision making depends on the choices available for the presented task. Most event-related potential (ERP) experiments are designed with two options, such as YES or NO. In some cases, however, subjects may become confused about the presented task in such a way that they cannot provide a behavioral response. This study aims to put subjects into such a puzzled state in order to address the following questions: How does the brain respond during puzzling moments? And what is the brain’s response to a non-answerable task? To address these questions, ERP were acquired from the brain during a scintillation grid illusion task. The subjects were required to count the number of illusory dots, a task that was impossible to perform. The results showed the presence of N130 over the parietal area during the puzzling task. Coherency among the brain hemispheres was enhanced with the complexity of the task. The neural generators’ source localizations were projected to a multimodal complex covering the left postcentral gyrus, supramarginal gyrus, and angular gyrus. This study concludes that the brain component N130 is strongly related to perception in a puzzling task network but not the visual processing network. PMID:28123804

  12. Understanding the proton radius puzzle: Nuclear structure effects in light muonic atoms

    CERN Document Server

    Ji, Chen; Dinur, Nir Nevo; Bacca, Sonia; Barnea, Nir

    2015-01-01

    We present calculations of nuclear structure effects to the Lamb shift in light muonic atoms. We adopt a modern ab-initio approach by combining state-of-the-art nuclear potentials with the hyperspherical harmonics method. Our calculations are instrumental to the determination of nuclear charge radii in the Lamb shift measurements, which will shed light on the proton radius puzzle.

  13. (Mis)perception of Sleep in Insomnia: A Puzzle and a Resolution

    Science.gov (United States)

    Harvey, Allison G.; Tang, Nicole K. Y.

    2012-01-01

    Insomnia is prevalent, causing severe distress and impairment. This review focuses on illuminating the puzzling finding that many insomnia patients misperceive their sleep. They overestimate their sleep onset latency (SOL) and underestimate their total sleep time (TST), relative to objective measures. This tendency is ubiquitous (although not…

  14. New data and an old puzzle : the negative association between schizophrenia and rheumatoid arthritis

    NARCIS (Netherlands)

    Lee, S Hong; Byrne, Enda M; Hultman, Christina M; Kähler, Anna; Vinkhuyzen, Anna Ae; Ripke, Stephan; Andreassen, Ole A; Frisell, Thomas; Gusev, Alexander; Hu, Xinli; Karlsson, Robert; Mantzioris, Vasilis X; McGrath, John J; Mehta, Divya; Stahl, Eli A; Zhao, Qiongyi; Kendler, Kenneth S; Sullivan, Patrick F; Price, Alkes L; O'Donovan, Michael; Okada, Yukinori; Mowry, Bryan J; Raychaudhuri, Soumya; Wray, Naomi R; Byerley, William; Cahn, Wiepke; Cantor, Rita M; Cichon, Sven; Cormican, Paul; Curtis, David; Djurovic, Srdjan; Escott-Price, Valentina; Gejman, Pablo V; Georgieva, Lyudmila; Giegling, Ina; Hansen, Thomas F; Ingason, Andrés; Kim, Yunjung; Konte, Bettina; Lee, Phil H; McIntosh, Andrew; McQuillin, Andrew; Morris, Derek W; Nöthen, Markus M; O'Dushlaine, Colm; Olincy, Ann; Olsen, Line; Pato, Carlos N; Pato, Michele T; Pickard, Benjamin S; Posthuma, Danielle; Rasmussen, Henrik B; Rietschel, Marcella; Rujescu, Dan; Schulze, Thomas G; Silverman, Jeremy M; Thirumalai, Srinivasa; Werge, Thomas; Agartz, Ingrid; Amin, Farooq; Azevedo, Maria H; Bass, Nicholas; Black, Donald W; Blackwood, Douglas H R; Bruggeman, Richard; Buccola, Nancy G; Choudhury, Khalid; Cloninger, Robert C; Corvin, Aiden; Craddock, Nicholas; Daly, Mark J; Datta, Susmita; Donohoe, Gary J; Duan, Jubao; Dudbridge, Frank; Fanous, Ayman; Freedman, Robert; Freimer, Nelson B; Friedl, Marion; Gill, Michael; Gurling, Hugh; De Haan, Lieuwe; Hamshere, Marian L; Hartmann, Annette M; Holmans, Peter A; Kahn, René S; Keller, Matthew C; Kenny, Elaine; Kirov, George K; Krabbendam, Lydia; Krasucki, Robert; Lawrence, Jacob; Lencz, Todd; Levinson, Douglas F; Lieberman, Jeffrey A; Lin, Dan-Yu; Linszen, Don H; Magnusson, Patrik Ke; Maier, Wolfgang; Malhotra, Anil K; Mattheisen, Manuel; Mattingsdal, Morten; McCarroll, Steven A; Medeiros, Helena; Melle, Ingrid; Milanova, Vihra; Myin-Germeys, Inez; Neale, Benjamin M; Ophoff, Roel A; Owen, Michael J; Pimm, Jonathan; Purcell, Shaun M; Puri, Vinay; Quested, Digby J; Rossin, Lizzy; Ruderfer, Douglas; Sanders, Alan R; Shi, Jianxin; Sklar, Pamela; St Clair, David; Scott Stroup, T; Van Os, Jim; Visscher, Peter M; Wiersma, Durk; Zammit, Stanley; Louis Bridges, S; Choi, Hyon K; Coenen, Marieke Jh; de Vries, Niek; Dieud, Philippe; Greenberg, Jeffrey D; Huizinga, Tom Wj; Padyukov, Leonid; Siminovitch, Katherine A; Tak, Paul P; Worthington, Jane; De Jager, Philip L; Denny, Joshua C; Gregersen, Peter K; Klareskog, Lars; Mariette, Xavier; Plenge, Robert M; van Laar, Mart; van Riel, Piet

    2015-01-01

    BACKGROUND: A long-standing epidemiological puzzle is the reduced rate of rheumatoid arthritis (RA) in those with schizophrenia (SZ) and vice versa. Traditional epidemiological approaches to determine if this negative association is underpinned by genetic factors would test for reduced rates of one

  15. Booklists for the Teaching of Mathematics in Schools: Puzzles, Problems, Games and Mathematical Recreations (Ref: PGR).

    Science.gov (United States)

    Mathematical Association, Leicester (England).

    Presented is a listing of books recommended by the Mathematical Association of the United Kingdom dealing with Puzzles, Problems, Games, and Mathematical Recreations. The following information on each book is provided: author; title; publisher; cost to the nearest pound; categories of use; and a code that indicates if the book in question is out…

  16. A solution to B --> pi pi puzzle and B --> K K

    CERN Document Server

    Baek, Seungwon

    2008-01-01

    The large ratio of color-suppressed tree amplitude to color-allowed one in $B \\to \\pi \\pi$ decays is difficult to understand within the Standard Model, which is known as the "$B \\to \\pi\\pi$ puzzle". The two tree diagrams contain the up- and charm-quark component of penguin amplitude, $P_{uc}$, which cannot be separated by measuring $B \\to \\pi \\pi$ decays alone. We show that the measurements of the branching ratio and direct CP asymmetry of $B^+ \\to K^+ \\bar{K^0}$ decay enable one to disentangle the $P_{uc}$ with two-fold ambiguity. One of the two degenerate solutions of the $P_{uc}$ can solve the $B \\to \\pi \\pi$ puzzle by giving $|C/T|\\sim 0.3$ which is consistent with the expectation in the Standard Model. We also show that the two solutions can be discriminated by the measurement of the indirect CP-asymmetry of $B^0 \\to K^0 \\ol{K^0}$. We point out that if the $B \\to \\pi \\pi$ puzzle is solved in this way, the corresponding puzzle in $B \\to \\pi K$ decays should have a different origin.

  17. Cryptographic Puzzles and Game Theory against DoS and DDoS attacks in Networks

    DEFF Research Database (Denmark)

    Mikalas, Antonis; Komninos, Nikos; Prasad, Neeli R.

    2008-01-01

    . In the second part we are introducing some basic principles of game theory and we discuss how game theoretical frameworks can protect computer networks. Finally, we show techniques that combine client puzzles with game theory in order to provide DoS and DDoS resilience....

  18. Precedents, Patterns and Puzzles: Feminist Reflections on the First Women Lawyers

    Directory of Open Access Journals (Sweden)

    Mary Jane Mossman

    2016-10-01

    Full Text Available This paper initially examines the historical precedents established by some of the first women who entered the “gentleman’s profession” of law in different jurisdictions, as well as the biographical patterns that shaped some women’s ambitions to enter the legal professions. The paper then uses feminist methods and theories to interpret “puzzles that remain unsolved” about early women lawyers, focusing especially on two issues. One puzzle is the repeated claims on the part of many of these early women lawyers that they were “lawyers”, and not “women lawyers”, even as they experienced exclusionary practices and discrimination on the part of male lawyers and judges—a puzzle that suggests how professional culture required women lawyers to conform to existing patterns in order to succeed. A second puzzle relates to the public voices of early women lawyers, which tended to suppress disappointments, difficulties and discriminatory practices. In this context, feminist theories suggest a need to be attentive to the “silences” in women’s stories, including the stories of the lives of early women lawyers. Moreover, these insights may have continuing relevance for contemporary women lawyers because it is at least arguable that, while there have been changes in women’s experiences, there has been very little transformation in their work status in relation to men.

  19. Enhancing the Understanding of Government and Nonprofit Accounting with THE PUZZLE GAME: A Pilot Study

    Science.gov (United States)

    Elson, Raymond J.; Ostapski, S. Andrew; O'Callaghan, Susanne; Walker, John P.

    2012-01-01

    Nontraditional teaching aids such as crossword puzzles have been successfully used in the classroom to enhance student learning. Government and nonprofit accounting is a confusing course for students since it has strange terminologies and contradicts the accounting concepts learned in other courses. As such, it is an ideal course for a…

  20. High-mass twins & resolution of the reconfinement, masquerade and hyperon puzzles of compact star interiors

    Energy Technology Data Exchange (ETDEWEB)

    Blaschke, David [Bogoliubov Laboratory for Theoretical Physics, JINR Dubna, 141980 Dubna (Russian Federation); Instytut Fizyki Teoretycznej, Uniwersytet Wroclawski, 50-204 Wroclaw (Poland); Alvarez-Castillo, David E. [Bogoliubov Laboratory for Theoretical Physics, JINR Dubna, 141980 Dubna (Russian Federation); Instituto de Física, Universidad Autónoma de San Luis Potosí, San Luis Potosí, México (Mexico)

    2016-01-22

    We aim at contributing to the resolution of three of the fundamental puzzles related to the still unsolved problem of the structure of the dense core of compact stars (CS): (i) the hyperon puzzle: how to reconcile pulsar masses of 2 M{sub ⊙} with the hyperon softening of the equation of state (EoS); (ii) the masquerade problem: modern EoS for cold, high density hadronic and quark matter are almost identical; and (iii) the reconfinement puzzle: what to do when after a deconfinement transition the hadronic EoS becomes favorable again? We show that taking into account the compositeness of baryons (by excluded volume and/or quark Pauli blocking) on the hadronic side and confining and stiffening effects on the quark matter side results in an early phase transition to quark matter with sufficient stiffening at high densities which removes all three present-day puzzles of CS interiors. Moreover, in this new class of EoS for hybrid CS falls the interesting case of a strong first order phase transition which results in the observable high mass twin star phenomenon, an astrophysical observation of a critical endpoint in the QCD phase diagram.

  1. High-mass twins & resolution of the reconfinement, masquerade and hyperon puzzles of compact star interiors

    CERN Document Server

    Blaschke, David

    2016-01-01

    We aim at contributing to the resolution of three of the fundamental puzzles related to the still unsolved problem of the structure of the dense core of compact stars (CS): (i) the hyperon puzzle: how to reconcile pulsar masses of $2\\,$M$_\\odot$ with the hyperon softening of the equation of state (EoS); (ii) the masquerade problem: modern EoS for cold, high density hadronic and quark matter are almost identical; and (iii) the reconfinement puzzle: what to do when after a deconfinement transition the hadronic EoS becomes favorable again? We show that taking into account the compositeness of baryons (by excluded volume and/or quark Pauli blocking) on the hadronic side and confining and stiffening effects on the quark matter side results in an early phase transition to quark matter with sufficient stiffening at high densities which removes all three present-day puzzles of CS interiors. Moreover, in this new class of EoS for hybrid CS falls the interesting case of a strong first order phase transition which resul...

  2. Instructional Media Production for Early Childhood Education: A. B. C. Jig-Saw Puzzle, a Model

    Science.gov (United States)

    Yusuf, Mudashiru Olalere; Olanrewaju, Olatayo Solomon; Soetan, Aderonke K.

    2015-01-01

    In this paper, a. b. c. jig-saw puzzle was produced for early childhood education using local materials. This study was a production based type of research, to serve as a supplemental or total learning resource. Its production followed four phases of development referred to as information, design, production and evaluation. The storyboard cards,…

  3. The Quark Puzzle: A Novel Approach to Visualizing the Color Symmetries of Quarks

    Science.gov (United States)

    Gettrust, Eric

    2010-01-01

    This paper describes a simple hands-on and visual-method designed to introduce physics students of many age groups to the topic of quarks and their role in forming composite particles (baryons and mesons). A set of puzzle pieces representing individual quarks that fit together in ways consistent with known restrictions of flavor, color, and charge…

  4. Neutrino oscillations in magnetized media and implications for the pulsar velocity puzzle

    CERN Document Server

    Grasso, D

    1998-01-01

    After a brief presentation of the general techniques used to determine neutrino potentials in a magnetized medium I will discuss MSW resonant oscillations of active and sterile neutrinos in such environment. Using my results I will reconsider the viability of a solution of the pulsar velocity puzzle based on such a kind of neutrino oscillations.

  5. Gardner's Two Children Problems and Variations: Puzzles with Conditional Probability and Sample Spaces

    Science.gov (United States)

    Taylor, Wendy; Stacey, Kaye

    2014-01-01

    This article presents "The Two Children Problem," published by Martin Gardner, who wrote a famous and widely-read math puzzle column in the magazine "Scientific American," and a problem presented by puzzler Gary Foshee. This paper explains the paradox of Problems 2 and 3 and many other variations of the theme. Then the authors…

  6. The Puzzle of Non-proliferation and Disarmament (Part II); El puzzle de la No-Proliferacion y el Desarme (segunda parte)

    Energy Technology Data Exchange (ETDEWEB)

    Ponga, J. de

    2011-07-01

    Since, in 1945, the World was aware of the devastating power of nuclear weapons there have been many initiatives at international level to avoid nuclear weapon proliferation: the foundation of the IAEA, the NPT, the Safeguards Agreements, the Nuclear Weapon Free Zones, the treaties banning nuclear tests or the export control regime of the NSG, among others. This article aims to offer a general picture of all of them as pieces of a puzzle the purpose of which is not to allow gaps to non pacific uses of nuclear energy. (Author)

  7. The Muon Scattering Experiment (MUSE at PSI and the proton radius puzzle

    Directory of Open Access Journals (Sweden)

    Kohl Michael

    2014-01-01

    Full Text Available The unexplained large discrepancy of the proton charge radius measurements with muonic hydrogen Lamb shift and determinations from elastic electron scattering and Lamb shift in regular hydrogen of seven standard deviations is known as the proton radius puzzle. Suggested solutions of the puzzle range from possible errors in the experiments through unexpectedly large hadronic physics effects to new physics beyond the Standard Model. A new approach to verify the radius discrepancy in a systematic manner will be pursued with the Muon Scattering Experiment (MUSE at PSI. The experiment aims to compare elastic cross sections, the proton elastic form factors, and the extracted proton charge radius with scattering of electrons and muons of either charge and under identical conditions. The difference in the observed radius will be probed with a high precision to verify the discrepancy. An overview of the experiment and the current status will be presented.

  8. Backus–Smith puzzle and the European Union: It’s not just the nominal exchange rate

    Directory of Open Access Journals (Sweden)

    Predrag Petrović

    2016-12-01

    Full Text Available he goal of our research is testing of presence and background examination of Backus–Smith puzzle in the EU. The research is based on the technique of econometric analysis of panel data, i.e. on the estimation of one-way/two-way error component models and models without effects. The results of the research have shown that: (a there is serious evidence on presence of the Backus–Smith puzzle in the EU, (b its background comprises both nominal exchange rate and inflation differential, and (c empirical data rejects complete risk sharing assumption strongly and decisively, but this does not explain the Backus–Smith puzzle. The basic conclusion of our research is that nominal exchange rate movements are not the only source of Backus–Smith puzzle in the EU, as is the case in OECD members states.

  9. The Puzzles of Politics: Inquiries into the genesis and transformation of international relations

    OpenAIRE

    KRATOCHWIL, Friedrich

    2011-01-01

    The Puzzles of Politics brings together for the first time a collection of his key essays to explain his approach to international relations and how his thinking has developed over the last 30 years. It addresses topical themes and issues central to his work including sovereignty, law, epistemology, boundaries, global governance and world society. The book includes a framing introduction written for this volume in which Kratochwil provides an intellectual biography providing context as well ...

  10. A Characterization of Achievable Patterns of the MN—Puzzle Problem

    Institute of Scientific and Technical Information of China (English)

    杨红青

    1990-01-01

    One important MN-puzzle problem is to find a sequcence of up-down and ight-left movements of the empty-cell so that a goal-pattern can be achieved from a given initial-pattern.The second problem is to characterize the totality of the goal-pattrn from a given initial-pattern.The third problem is finding the fewest movements to achieve it.In this paper,these problems will be completely solved.

  11. An Analysis of Closed-end Fund Puzzle for Emerging Capital Markets

    Directory of Open Access Journals (Sweden)

    Victor Dragota

    2008-10-01

    Full Text Available This paper analyzes the closed-end fund puzzle for an emerging capital market, respectively the Romanian one. Comparatively to more developed markets, as long as small markets are often very illiquid, it has to be used some specific valuation techniques in order to estimate the market values for closed-end funds. Also, one problem is this estimation can be made only in some (punctual moments.

  12. Understanding the proton radius puzzle: Nuclear structure effects in light muonic atoms

    Directory of Open Access Journals (Sweden)

    Ji Chen

    2016-01-01

    Full Text Available We present calculations of nuclear structure effects to the Lamb shift in light muonic atoms. We adopt a modern ab-initio approach by combining state-of-the-art nuclear potentials with the hyperspherical harmonics method. Our calculations are instrumental to the determination of nuclear charge radii in the Lamb shift measurements, which will shed light on the proton radius puzzle.

  13. Padrão dos fluxos de capitais: teoria, evidência e puzzle

    Directory of Open Access Journals (Sweden)

    Aderbal Oliveira Damasceno

    2014-04-01

    Full Text Available Este trabalho desenvolve uma análise teórica e empírica sobre o padrão de longo prazo dos fluxos de capitais. Com uma amostra de 105 países e dados para o período 1980-2004, a metodologia econométrica abrange modelos para cross-section e para dados em painel. Os resultados apresentados sugerem: i incoerência entre as previsões do modelo neoclássico e o padrão observado dos fluxos de capitais, o que caracteriza o puzzle ; ii no âmbito da abordagem convencional, as explicações para o puzzle são diferenças de fundamentos entre países e imperfeições no mercado financeiro; iii não há evidências de que diferenças entre os países relativas ao ambiente institucional, estoque de capital humano, integração financeira, política macroeconòmica e desenvolvimento financeiro expliquem o puzzle. Considerando os resultados apresentados, esboça-se uma explicação alternativa de inspiração heterodoxa para o padrão dos fluxos de capitais.

  14. Toward a virtual reconstruction of an antique three-dimensional marble puzzle

    Science.gov (United States)

    Benamar, Fatima Zahra; Fauvet, Eric; Hostein, Antony; Laligant, Olivier; Truchetet, Frederic

    2017-01-01

    The reconstruction of broken objects is an important field of research for many applications, such as art restoration, surgery, forensics, and solving puzzles. In archaeology, the reconstruction of broken artifacts is a very time-consuming task due to the handling of fractured objects, which are generally fragile. However, it can now be supported by three-dimensional (3-D) data acquisition devices and computer processing. Those techniques are very useful in this domain because they allow the remote handling of very accurate models of fragile parts, they permit the extensive testing of reconstruction solutions, and they provide access to the parts for the entire research community. An interesting problem has recently been proposed by archaeologists in the form of a huge puzzle composed of a thousand fragments of Pentelic marble of different sizes found in Autun (France), and all attempts to reconstruct the puzzle during the last two centuries have failed. Archaeologists are sure that some fragments are missing and that some of the ones we have come from different slabs. We propose an inexpensive transportable system for 3-D acquisition setup and a 3-D reconstruction method that is applied to this Roman inscription but is also relevant to other applications.

  15. Evolutionary, neurobiological, gene-based solution of the ideological "puzzle" of human altruism and cooperation.

    Science.gov (United States)

    Baschetti, Riccardo

    2007-01-01

    Despite hundreds of published articles about humankind's eusocial behaviours, most scholars still regard the origin of human altruism and cooperation as an enduring puzzle, because it seems incompatible with two central tenets of evolution, namely, the competition between individuals and the consequent selective advantages of selfish traits. This "puzzle", however, rather than being due to insurmountable scientific difficulties, is to be attributed to two powerful ideologies, which are politically opposite, but nevertheless concurred to prevent scholars from solving it. One ideology rejects the concept of genetic determinism, whereas the other dislikes the concept of group selection. As a consequence, these widespread ideologies, which are common in the scientific community, too, kept scholars from realising that the puzzle of human altruism and cooperation can only be solved by proposing a theoretical model that is based precisely on both genetic determinism and group selection. This model, which was never advanced in published papers, is presented here. This article also proposes to regard ancestral environments as determinants of human eusociality. By contrast, virtually all previous articles about it leave primitive habitats unmentioned. To support the hypothesis that human unselfish behaviours represent genetically conserved traits that evolved ancestrally, not products of cultural transmission, this paper also discusses six groups of arguments in the section "Genes versus culture". Finally, this article advances a purely genetic evolutionary explanation for the uniqueness of human eusociality, thereby challenging prevailing cultural explanations for the incomparably developed levels of cooperation in humankind, which are observed in no other social species.

  16. Does random tree puzzle produce Yule-Harding trees in the many-taxon limit?

    Science.gov (United States)

    Zhu, Sha; Steel, Mike

    2013-05-01

    It has been suggested that a random tree puzzle (RTP) process leads to a Yule-Harding (YH) distribution, when the number of taxa becomes large. In this study, we formalize this conjecture, and we prove that the two tree distributions converge for two particular properties, which suggests that the conjecture may be true. However, we present statistical evidence that, while the two distributions are close, the RTP appears to converge on a different distribution than does the YH. By way of contrast, in the concluding section we show that the maximum parsimony method applied to random two-state data leads a very different (PDA, or uniform) distribution on trees.

  17. Exchange rate regimes, saving glut and the Feldstein Horioka puzzle: The East Asian experience

    Science.gov (United States)

    Kaya-Bahçe, Seçil; Özmen, Erdal

    2008-04-01

    This paper investigates whether the recent experience of the emerging East Asian countries with current account surpluses is consistent with the “saving glut” hypothesis and the Feldstein and Horioka puzzle. The evidence suggests that the saving retention coefficients declined substantially in most of the countries after an endogenous break date coinciding with a major exchange rate regime change with the 1997-1998 crisis. Exchange rate flexibility appears to be enhancing financial integration. The results are consistent with an “investment slump” explanation rather than the “saving glut” postulation.

  18. High-energy cosmic rays: Puzzles, models, and giga-ton neutrino telescopes

    Indian Academy of Sciences (India)

    E Waxman

    2004-02-01

    The existence of cosmic rays of energies exceeding 1020 eV is one of the mysteries of high-energy astrophysics. The spectrum and the high energy to which it extends rule out almost all suggested source models. The challenges posed by observations to models for the origin of high-energy cosmic rays are reviewed, and the implications of recent new experimental results are discussed. Large area high-energy cosmic ray detectors and large volume high-energy neutrino detectors currently under construction may resolve the high-energy cosmic ray puzzle, and shed light on the identity and physics of the most powerful accelerators in the Universe.

  19. The Resolution of an Entropy Puzzle for 4D non-BPS Black Holes

    CERN Document Server

    Banerjee, Nabamita; Lodato, Ivano

    2016-01-01

    We show the equality between macroscopic and microscopic black hole entropy for a class of four dimensional non-supersymmetric black holes in ${\\cal N}=2$ supergravity theory, up to the first subleading order in their charges. This solves a long standing entropy puzzle for this class of black holes. The macroscopic entropy has been computed in the presence of a newly derived higher-derivative supersymmetric invariant of \\cite{{Butter:2013lta}}, connected to the five dimensional supersymmetric Weyl squared Lagrangian. Microscopically, the crucial role in obtaining the equivalence is played by the anomalous gauge gravitational Chern-Simons term.

  20. A Game Architecture for Emergent Story-Puzzles in a Persistent World

    OpenAIRE

    Peinado, Federico

    2005-01-01

    This paper presents the design of a semi-emergent architecture for graphic adventures. The proposed architecture is able to create new significant story-puzzles on the fly, combining preauthored material in a coherent and emergent way. As a test-bed of this architecture we use a simple detective game inspired on the famous boardgame Cluedo. INTRODUCTION There are a lot of adventure games in the market and some of them try to tell a re-playable story that change and become slightly different f...

  1. A 17 keV neutrino and large magnetic moment solution of the solar neutrino puzzle

    Science.gov (United States)

    Akhmedov, E. Kh.; Senjanovic, G.; Tao, Zhijian; Berezhiani, Z. G.

    1992-08-01

    Zee-type models with Majorons naturally incorporate the 17 keV neutrino but in their minimal version fail to simultaneously solve the solar neutrino puzzle. If there is a sterile neutrino state, a particularly simple solution is found to the solar neutrino problem, which besides nu(sub 17) predicts a light Zeldovich-Konopinski-Mahmoud neutrino nu(sub light) = nu(sub e) + nu(sub mu)(sup c) with a magnetic moment being easily as large as 10(exp -11)(mu)(sub B) through the Barr-Freire-Zee mechanism.

  2. 17 keV neutrino and large magnetic moment solution of the solar neutrino puzzle

    Science.gov (United States)

    Akhmedov, Eugeni Kh.; Berezhiani, Zurab G.; Senjanović, Goran; Tao, Zhijian

    1993-01-01

    Zee-type models with majorons naturally incorporate the 17 keV neutrino but in their minimal version fail to simultaneously solve the solar neutrino puzzle. If there is a sterile neutrino state, we find a particularly simple solution to the solar neutrino problem, which besides ν17 predicts a light Zeldovich-Konopinski-Mahmoud neutrino νlight = νe + νcμ with a magnetic moment being easily as large as 10 -11μB through the Barr-Freire-Zee mechanism.

  3. Puzzling asymmetries

    CERN Multimedia

    Antonella Del Rosso

    2012-01-01

    In a recently published paper, the LHCb Collaboration has reported on a possible deviation from the Standard Model. Theorists are now working to calculate precisely this effect and to evaluate the implications that such unexpected result could have on the established theory.   The Standard Model is able to predict the decay rates of particles with high precision. In most cases, experimentalists confirm the value predicted by theory and the figure is added to the official publications. However, this time, things seem to have taken a different route. Studying data collected in 2011, the LHCb Collaboration found that in a specific decay – a B particle transforming into a K particle plus two charged muons (B -> Kμ-μ+) – the branching ratio of the neutral B in the corresponding decay (i.e. B0 -> K0μ-μ+) is different from that of the positively charged B (i.e. B+ -> K+μ-μ+). Such an “isospin asymmetry&rdquo...

  4. Puzzling asymmetries

    CERN Multimedia

    Antonella Del Rosso

    2012-01-01

    In a recently published paper, the LHCb collaboration reported on a possible deviation from the Standard Model. Theorists are now working to calculate precisely this effect and to evaluate the implications that such an unexpected result could have on the established theory.   The Standard Model is able to predict the decay rates of particles with high precision. In most cases, experimentalists confirm the value predicted by theory and the figure is added to the official publications. However, this time, things seem to have taken a different route. Studying data collected in 2011, the LHCb collaboration found that in a specific decay – a B particle transforming into a K particle plus two charged muons (B -> Kμ-μ+) – the branching ratio of the neutral B in the corresponding decay (i.e. B0 -> K0μ-μ+) was different it that of the positively charged B (i.e. B+ -> K+μ-μ+). Such an “isospin asymmetry”...

  5. Puzzling antimatter

    CERN Multimedia

    Francesco Poppi

    2010-01-01

    For many years, the absence of antimatter in the Universe has tantalised particle physicists and cosmologists: while the Big Bang should have created equal amounts of matter and antimatter, we do not observe any primordial antimatter today. Where has it gone? The LHC experiments have the potential to unveil natural processes that could hold the key to solving this paradox.   Every time that matter is created from pure energy, equal amounts of particles and antiparticles are generated. Conversely, when matter and antimatter meet, they annihilate and produce light. Antimatter is produced routinely when cosmic rays hit the Earth's atmosphere, and the annihilations of matter and antimatter are observed during physics experiments in particle accelerators. If the Universe contained antimatter regions, we would be able to observe intense fluxes of photons at the boundaries of the matter/antimatter regions. “Experiments measuring the diffuse gamma-ray background in the Universe would be able...

  6. Heavy flavor puzzle at LHC: a serendipitous interplay of jet suppression and fragmentation.

    Science.gov (United States)

    Djordjevic, Magdalena

    2014-01-31

    Both charged hadrons and D mesons are considered to be excellent probes of QCD matter created in ultrarelativistic heavy ion collisions. Surprisingly, recent experimental observations at LHC show the same jet suppression for these two probes, which--contrary to pQCD expectations--may suggest similar energy losses for light quarks and gluons in the QCD medium. We here use our recently developed energy loss formalism in a finite-size dynamical QCD medium to analyze this phenomenon that we denote as the "heavy flavor puzzle at LHC." We show that this puzzle is a consequence of an unusual combination of the suppression and fragmentation patterns and, in fact, does not require invoking the same energy loss for light partons. Furthermore, we show that this combination leads to a simple relationship between the suppressions of charged hadrons and D mesons and the corresponding bare quark suppressions. Consequently, a coincidental matching of jet suppression and fragmentation allows considerably simplifying the interpretation of the corresponding experimental data.

  7. Toward a solution to the RAA and v2 puzzle for heavy quarks

    Directory of Open Access Journals (Sweden)

    Santosh K. Das

    2015-07-01

    Full Text Available The heavy quarks constitute a unique probe of the quark–gluon plasma properties. A puzzling relation between the nuclear modification factor RAA(pT and the elliptic flow v2(pT has been observed both at RHIC and LHC energies. Predicting correctly both observables has been a challenge to all existing models, especially for D mesons. We discuss how the temperature dependence of the heavy quark drag coefficient is responsible for a large part of such a puzzle. In particular, we have considered four different models to evaluate the temperature dependence of drag and diffusion coefficients propagating through a quark gluon plasma (QGP. All the four different models are set to reproduce the same RAA(pT observed in experiments at RHIC and LHC energy. We point out that for the same RAA(pT one can generate 2–3 times more v2 depending on the temperature dependence of the heavy quark drag coefficient. A non-decreasing drag coefficient as T→Tc is a major ingredient for a simultaneous description of RAA(pT and v2(pT.

  8. Simultaneous explanation of the RK and R(D(⁎ puzzles

    Directory of Open Access Journals (Sweden)

    Bhubanjyoti Bhattacharya

    2015-03-01

    Full Text Available At present, there are several hints of lepton flavor non-universality. The LHCb Collaboration has measured RK≡B(B+→K+μ+μ−/B(B+→K+e+e−, and the BaBar Collaboration has measured R(D(⁎≡B(B¯→D(⁎+τ−ν¯τ/B(B¯→D(⁎+ℓ−ν¯ℓ (ℓ=e,μ. In all cases, the experimental results differ from the standard model predictions by 2–3σ. Recently, an explanation of the RK puzzle was proposed in which new physics (NP generates a neutral-current operator involving only third-generation particles. Now, assuming the scale of NP is much larger than the weak scale, this NP operator must be made invariant under the full SU(3C×SU(2L×U(1Y gauge group. In this Letter, we note that, when this is done, a new charged-current operator can appear, and this can explain the R(D(⁎ puzzle. A more precise measurement of the double ratio R(D/R(D⁎ can rule out this model.

  9. Toward a solution to the $R_{AA}$ and $v_2$ puzzle for heavy quarks

    CERN Document Server

    Das, Santosh K; Plumari, Salvatore; Greco, Vincenzo

    2015-01-01

    The heavy quarks constitutes a unique probe of the quark-gluon plasma properties. Both at RHIC and LHC energies a puzzling relation between the nuclear modification factor $R_{AA}(p_T)$ and the elliptic flow $v_2(p_T)$ has been observed which challenged all the existing models, especially for D mesons. We discuss how the temperature dependence of the heavy quark drag coefficient is responsible to address for a large part of such a puzzle. In particular, we have considered four different models to evaluate the temperature dependence of drag and diffusion coefficients propagating through a quark gluon plasma (QGP). All the four different models are set to reproduce the same $R_{AA}(p_T)$ observed in experiments at RHIC and LHC energy. We point out that for the same $R_{AA}(p_T)$ one can generate 2-3 times more $v_2$ depending on the temperature dependence of the heavy quark drag coefficient. An increasing drag coefficient as $ T \\rightarrow\\ T_c \\,$ is a major ingredient for a simultaneous description of $R_{AA...

  10. Solving the Solar Neutrino Puzzle with KamLAND and Solar Data

    CERN Document Server

    De Gouvêa, A; Gouv\\^ea, Andr\\'e de

    2001-01-01

    We study what will be learnt about the solar neutrino puzzle and solar neutrino oscillations once the data from the KamLAND reactor neutrino experiment (soon to become available) are combined with those from the current solar neutrino experiments. We find that, in agreement with previous estimates, if the solution to the solar neutrino puzzle falls on the LMA region, KamLAND should be able to ``pin-point'' the right solution with unprecedented accuracy after a few years of data taking. Furthermore, the light side ($\\theta\\pi/4$) at the 95% confidence level (CL) for most of the LMA region allowed by the current data at the 99% CL, while the addition of the KamLAND data need not improve our ability to limit a sterile component in ``solar'' oscillations. If KamLAND does not see an oscillation signal, the solar data would point to the LOW/VAC regions, while the SMA region would still lurk at the two sigma CL, meaning we would probably have to wait for Borexino data in order to finally piece the solar neutrino puz...

  11. Understanding the ``Proton Radius Puzzle'': Nuclear Polarizability Correction in μD

    Science.gov (United States)

    Hernandez, Oscar J.; Dinur, Nir Nevo; Ji, Chen; Bacca, Sonia; Barnea, Nir

    2016-09-01

    The accuracy of the proton radius was improved ten-fold by new spectroscopic measurements in muonic hydrogen but it differs by 7 σ from hydrogen determinations. This discrepancy, has been coined the ``proton radius puzzle''. The results of new high-precision experiments on muonic deuterium indicate a new deuterium radius puzzle. The accuracy of the nuclear charge radius determination from these measurements is limited by the uncertainty in the nuclear structure effects. We have calculated this correction in Ref. including the first estimate of the nuclear-model dependence. Due to the importance of constraining the uncertainty, we will determine the statistical and systematic uncertainties of the χEFT potentials by determining the co-variance matrices of our predictions. I will also discuss an alternate method that may reduce the theoretical uncertainty. TRIUMF receives federal funding via a contribution agreement with the National Research Council of Canada. This work was supported in parts by the Natural Sciences and Engineering Research Council (Grant Number SAPIN-2015-00031).

  12. A puzzle form of a non-verbal intelligence test gives significantly higher performance measures in children with severe intellectual disability

    Directory of Open Access Journals (Sweden)

    Crewther Sheila G

    2008-08-01

    Full Text Available Abstract Background Assessment of 'potential intellectual ability' of children with severe intellectual disability (ID is limited, as current tests designed for normal children do not maintain their interest. Thus a manual puzzle version of the Raven's Coloured Progressive Matrices (RCPM was devised to appeal to the attentional and sensory preferences and language limitations of children with ID. It was hypothesized that performance on the book and manual puzzle forms would not differ for typically developing children but that children with ID would perform better on the puzzle form. Methods The first study assessed the validity of this puzzle form of the RCPM for 76 typically developing children in a test-retest crossover design, with a 3 week interval between tests. A second study tested performance and completion rate for the puzzle form compared to the book form in a sample of 164 children with ID. Results In the first study, no significant difference was found between performance on the puzzle and book forms in typically developing children, irrespective of the order of completion. The second study demonstrated a significantly higher performance and completion rate for the puzzle form compared to the book form in the ID population. Conclusion Similar performance on book and puzzle forms of the RCPM by typically developing children suggests that both forms measure the same construct. These findings suggest that the puzzle form does not require greater cognitive ability but demands sensory-motor attention and limits distraction in children with severe ID. Thus, we suggest the puzzle form of the RCPM is a more reliable measure of the non-verbal mentation of children with severe ID than the book form.

  13. An Effective Method of Introducing the Periodic Table as a Crossword Puzzle at the High School Level

    Science.gov (United States)

    Joag, Sushama D.

    2014-01-01

    A simple method to introduce the modern periodic table of elements at the high school level as a game of solving a crossword puzzle is presented here. A survey to test the effectiveness of this new method relative to the conventional method, involving use of a wall-mounted chart of the periodic table, was conducted on a convenience sample. This…

  14. Puzzles in modern biology. III.Two kinds of causality in age-related disease

    Science.gov (United States)

    Frank, Steven A.

    2017-01-01

    The two primary causal dimensions of age-related disease are rate and function. Change in rate of disease development shifts the age of onset. Change in physiological function provides necessary steps in disease progression. A causal factor may alter the rate of physiological change, but that causal factor itself may have no direct physiological role. Alternatively, a causal factor may provide a necessary physiological function, but that causal factor itself may not alter the rate of disease onset. The rate-function duality provides the basis for solving puzzles of age-related disease. Causal factors of cancer illustrate the duality between rate processes of discovery, such as somatic mutation, and necessary physiological functions, such as invasive penetration across tissue barriers. Examples from cancer suggest general principles of age-related disease.

  15. A Theoretical Model of Jigsaw-Puzzle Pattern Formation by Plant Leaf Epidermal Cells.

    Science.gov (United States)

    Higaki, Takumi; Kutsuna, Natsumaro; Akita, Kae; Takigawa-Imamura, Hisako; Yoshimura, Kenji; Miura, Takashi

    2016-04-01

    Plant leaf epidermal cells exhibit a jigsaw puzzle-like pattern that is generated by interdigitation of the cell wall during leaf development. The contribution of two ROP GTPases, ROP2 and ROP6, to the cytoskeletal dynamics that regulate epidermal cell wall interdigitation has already been examined; however, how interactions between these molecules result in pattern formation remains to be elucidated. Here, we propose a simple interface equation model that incorporates both the cell wall remodeling activity of ROP GTPases and the diffusible signaling molecules by which they are regulated. This model successfully reproduces pattern formation observed in vivo, and explains the counterintuitive experimental results of decreased cellulose production and increased thickness. Our model also reproduces the dynamics of three-way cell wall junctions. Therefore, this model provides a possible mechanism for cell wall interdigitation formation in vivo.

  16. The puzzling assembly of the Milky Way halo – contributions from dwarf Spheroidals and globular clusters

    Directory of Open Access Journals (Sweden)

    Lépine S.

    2012-02-01

    Full Text Available While recent sky surveys have uncovered large numbers of ever fainter Milky Way satellites, their classification as star clusters, low-luminosity galaxies, or tidal overdensities remains often unclear. Likewise, their contributions to the build-up of the halo is yet debated. In this contribution we will discuss the current knowledge of the stellar populations and chemo-dynamics in these puzzling satellites, with a particular focus on dwarf spheroidal galaxies and the globular clusters in the outer Galactic halo. Also the question of whether some of the outermost halo objects are dynamically associated with the (Milky Way halo at all is addressed in terms of proper measurements in the remote Leo I and II dwarf galaxies.

  17. From inflation to dark energy through a dynamical Lambda: an attempt at alleviating fundamental cosmic puzzles

    CERN Document Server

    Basilakos, S; Solà, J

    2013-01-01

    After decades of successful hot big-bang paradigm, Cosmology still lacks a framework in which the early inflationary phase of the universe smoothly matches the radiation epoch and evolves to the present `quasi' de Sitter spacetime. No less intriguing is that the current value of the effective vacuum energy density is vastly smaller than the value that triggered inflation. In this Essay we propose a new class of cosmologies capable of overcoming, or highly alleviating, some of these acute cosmic puzzles. Powered by a decaying vacuum energy density, the spacetime emerges from a pure nonsingular de Sitter vacuum stage, "gracefully" exits from inflation to a radiation phase followed by dark matter and vacuum regimes, and, finally, evolves to a late time de Sitter phase.

  18. Anomalies in psi(2S) decay and the rho-pi puzzle

    CERN Document Server

    Suzuki, M

    2000-01-01

    We examine the so-called rho-pi puzzle of the psi(2S) decay by incorporating two inputs: One is the relative phase between the one-photon and the gluon decay amplitude, and the other is a possible anomaly in the inclusive nonelectromagnetic decay rate of psi(2S). We propose the possibility that in the psi(2S) decay a hadronic decay process of long distance origin is important in addition to the short-distance decay process. The amplitude of this additional process should nearly cancel the three-gluon amplitude in the exclusive psi(2S)---> 1-0- and turn the sum dominantly real in contrast to the J/psi decay. We present general consequences of this mechanism and then briefly look into two models which possibly explain the course of this additional amplitude.

  19. Hyperon puzzle and the RMF model with scaled hadron masses and coupling constants

    Science.gov (United States)

    Kolomeitsev, E. E.; Maslov, K. A.; Voskresensky, D. N.

    2016-01-01

    The equation of state of cold baryonic matter is studied within a relativistic mean-field model with hadron masses and coupling constants depending on a scalar field. We demonstrate that if the effective nucleon mass stops to decrease with a density increase at densities n > n*> n0, where n0 is the nuclear saturation density, the equation of state stiffens for these densities and the limiting neutron star mass increases. The stabilization of the nucleon mass can be realised if in the equation of motion for the scalar mean-field there appear a term sharply varying in a narrow vicinity of the field value corresponding to the density n*. We show several possible realizations of this mechanism getting sufficiently stiff equations of state. The appearance of hyperons in dense neutron star interiors is accounted for. The obtained equations of state remain sufficiently stiff if the reduction of the ϕ meson mass is incorporated. Thereby, the hyperon puzzle can be resolved.

  20. Old puzzle, new insights: a lithium rich giant quietly burning helium in its core

    CERN Document Server

    Aguirre, V Silva; Hekker, S; Cassisi, S; Christensen-Dalsgaard, J; Datta, A; Jendreieck, A; Jessen-Hansen, J; Mazumdar, A; Mosser, B; Stello, D; Beck, P G; de Ridder, J

    2014-01-01

    About 1% of giant stars have been shown to have large surface Li abundances, which is unexpected according to standard stellar evolution models. Several scenarios for lithium production have been proposed, but it is still unclear why these Li-rich giants exist. A missing piece in this puzzle is the knowledge of the exact stage of evolution of these stars. Using low-and-high-resolution spectroscopic observations, we have undertaken a survey of lithium-rich giants in the Kepler field. In this letter, we report the finding of the first confirmed Li-rich core-helium-burning giant, as revealed by asteroseismic analysis. The evolutionary timescales constrained by its mass suggest that Li-production most likely took place through non-canonical mixing at the RGB-tip, possibly during the helium flash.

  1. Simon`s Puzzle: Heuristics in the Process of Making Political Choices

    Directory of Open Access Journals (Sweden)

    Mateusz Wajzer

    2014-07-01

    Full Text Available In this article we analyse one of the most fascinating paradoxes of mass politics. Based on the data from the studies of neurobiologists, neurologists, social psychology, cognitive and evolution studies we answer the question specified in literature as the Simon’s puzzle: How is it possible that citizens have their opinions about politics, if they know so little about it? We began our analysis from the criticism of the economic rationality approach. To do this, we referred to the Allais paradox, cognitive dissonance theory, Ellsberg paradox, the concept of bounded rationality, conjunction fallacy and prospect theory. Next, we described the evolutionary processes shaping the minds of Homo sapiens and characterised cognitive mechanisms, thanks to which people can make political choices, especially in view of the shortage of time and information. The following heuristics are referred to herein: affect, recognition, judgment and imitation.

  2. OLD PUZZLE, NEW INSIGHTS: A LITHIUM-RICH GIANT QUIETLY BURNING HELIUM IN ITS CORE

    Energy Technology Data Exchange (ETDEWEB)

    Aguirre, V. Silva; Christensen-Dalsgaard, J.; Jessen-Hansen, J. [Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C (Denmark); Ruchti, G. R. [Lund Observatory, Department of Astronomy and Theoretical Physics, Box 43, SE-221 00 Lund (Sweden); Hekker, S. [Max-Planck-Institut für Sonnensystemforschung, Justus-von-Liebig-Weg 3, D-37077 Göttingen (Germany); Cassisi, S. [INAF-Astronomical Observatory of Teramo, Via M. Maggini sn, I-64100 Teramo (Italy); Datta, A. [Department of Physics and Meteorology, Indian Institute of Technology, Kharagpur 721302 (India); Jendreieck, A. [Max-Planck-Institut für Astrophysics, Karl Schwarzschild Strasse 1, D-85748 Garching (Germany); Mazumdar, A. [Homi Bhabha Centre for Science Education, TIFR, V. N. Purav Marg, Mankhurd, Mumbai 400088 (India); Mosser, B. [LESIA Observatoire de Paris, CNRS, Université Pierre et Marie Curie, Université Denis Diderot, F-92195 Meudon Cedex (France); Stello, D. [Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 2006 (Australia); Beck, P. G.; De Ridder, J. [Instituut voor Sterrenkunde, KU Leuven, Celestijnenlaan 200D, B-3001 Leuven (Belgium)

    2014-03-20

    About 1% of giant stars have been shown to have large surface Li abundances, which is unexpected according to standard stellar evolution models. Several scenarios for lithium production have been proposed, but it is still unclear why these Li-rich giants exist. A missing piece in this puzzle is the knowledge of the exact stage of evolution of these stars. Using low- and-high-resolution spectroscopic observations, we have undertaken a survey of lithium-rich giants in the Kepler field. In this Letter, we report the finding of the first confirmed Li-rich core-helium-burning giant, as revealed by asteroseismic analysis. The evolutionary timescales constrained by its mass suggest that Li production most likely took place through non-canonical mixing at the RGB tip, possibly during the helium flash.

  3. Completing the nuclear reaction puzzle of the nucleosynthesis of 92Mo

    CERN Document Server

    Tveten, G M; Schwengner, R; Naqvi, F; Larsen, A C; Eriksen, T K; Garrote, F L Bello; Bernstein, L A; Bleuel, D L; Campo, L Crespo; Guttormsen, M; Giacoppo, F; Görgen, A; Hagen, T W; Hadynska-Klek, K; Klintefjord, M; Meyer, B S; Nyhus, H T; Renstrøm, T; Rose, S J; Sahin, E; Siem, S; Tornyi, T G

    2016-01-01

    One of the greatest questions for modern physics to address is how elements heavier than iron are created in extreme, astrophysical environments. A particularly challenging part of that question is the creation of the so-called p-nuclei, which are believed to be mainly produced in some types of supernovae. The lack of needed nuclear data presents an obstacle in nailing down the precise site and astrophysical conditions. In this work, we present for the first time measurements on the nuclear level density and average strength function of $^{92}$Mo. State-of-the-art p-process calculations systematically underestimate the observed solar abundance of this isotope. Our data provide stringent constraints on the $^{91}$Nb$(p,{\\gamma})^{92}$Mo reaction rate, which is the last unmeasured reaction in the nucleosynthesis puzzle of $^{92}$Mo. Based on our results, we conclude that the $^{92}$Mo abundance anomaly is not due to the nuclear physics input to astrophysical model calculations.

  4. Well-Defined Cyclic Triblock Terpolymers: A Missing Piece of the Morphology Puzzle

    KAUST Repository

    Polymeropoulos, George

    2016-10-27

    Two well-defined cyclic triblock terpolymers, missing pieces of the terpolymer morphology puzzle, consisting of poly(isoprene), polystyrene, and poly(2-vinylpyridine), were synthesized by combining the Glaser coupling reaction with anionic polymerization. An α,ω-dihydroxy linear triblock terpolymer (OH-PI1,4-b-PS-b-P2VP-OH) was first synthesized followed by transformation of the OH to alkyne groups by esterification with pentynoic acid and cyclization by Glaser coupling. The size exclusion chromatography (SEC) trace of the linear terpolymer precursor was shifted to lower elution time after cyclization, indicating the successful synthesis of the cyclic terpolymer. Additionally, the SEC trace of the cyclic terpolymer produced, after cleavage of the ester groups, shifted again practically to the position corresponding to the linear precursor. The first exploratory results on morphology showed the tremendous influence of the cyclic structure on the morphology of terpolymers. © 2016 American Chemical Society.

  5. Towards the resolution of the e+e- --> Nbar N puzzle

    CERN Document Server

    Karliner, M M

    2002-01-01

    We discuss the puzzling experimental results on baryon-antibaryon production in e+e- annihilation close to the threshold, in particular the fact that sigma(e+e- --> nbar n) is somewhat greater than sigma(e+e- --> pbar p). We discuss an interpretation in terms of a two-step process, via an intermediate coherent isovector state serving as an intermediary between e+e- and the baryon-antibaryon system. We provide evidence that the isovector channel dominates both e+e- --> pions and from Nbar N annihilation at rest, and show that the observed ratio of sigma(e+e- --> nbar n)/sigma(e+e- --> pbar p) can be understood quantitatively in this picture.

  6. Defense of the Least Squares Solution to Peelle’s Pertinent Puzzle

    Directory of Open Access Journals (Sweden)

    Nicolas Hengartner

    2011-02-01

    Full Text Available Generalized least squares (GLS for model parameter estimation has a long and successful history dating to its development by Gauss in 1795. Alternatives can outperform GLS in some settings, and alternatives to GLS are sometimes sought when GLS exhibits curious behavior, such as in Peelle’s Pertinent Puzzle (PPP. PPP was described in 1987 in the context of estimating fundamental parameters that arise in nuclear interaction experiments. In PPP, GLS estimates fell outside the range of the data, eliciting concerns that GLS was somehow flawed. These concerns have led to suggested alternatives to GLS estimators. This paper defends GLS in the PPP context, investigates when PPP can occur, illustrates when PPP can be beneficial for parameter estimation, reviews optimality properties of GLS estimators, and gives an example in which PPP does occur.

  7. On the puzzling feature of the silence of precursory electromagnetic emissions

    CERN Document Server

    Eftaxias, K; Chelidze, T

    2012-01-01

    It has been suggested that fracture induced MHz-kHz electromagnetic (EM) emissions, which emerge from a few days up to a few hours before the main seismic shock occurrence, in accordance with the laboratory experiments, permit a real time monitoring of damage process of last stages of earthquake preparation process, as it is happens at the laboratory scale. Despite fairly abundant evidence, EM precursors have not been adequately accepted as credible physical quantities. These negative views are enhanced by the fact that certain "puzzling features" are consistently observed in candidate pre-seismic EM emissions. More precisely, EM silence in all frequency bands appears before the main seismic shock occurrence, as well as during the aftershock period. Actually, the view that "acceptance of 'precursive' EM signals without convincing co-seismic signals should not be expected" seems to be reasonable. In this work we focus on this point. We examine whether the aforementioned features of EM silence are really puzzli...

  8. Gold-nanoparticle-mediated jigsaw-puzzle-like assembly of supersized plasmonic DNA origami.

    Science.gov (United States)

    Yao, Guangbao; Li, Jiang; Chao, Jie; Pei, Hao; Liu, Huajie; Zhao, Yun; Shi, Jiye; Huang, Qing; Wang, Lianhui; Huang, Wei; Fan, Chunhai

    2015-03-02

    DNA origami has rapidly emerged as a powerful and programmable method to construct functional nanostructures. However, the size limitation of approximately 100 nm in classic DNA origami hampers its plasmonic applications. Herein, we report a jigsaw-puzzle-like assembly strategy mediated by gold nanoparticles (AuNPs) to break the size limitation of DNA origami. We demonstrated that oligonucleotide-functionalized AuNPs function as universal joint units for the one-pot assembly of parent DNA origami of triangular shape to form sub-microscale super-origami nanostructures. AuNPs anchored at predefined positions of the super-origami exhibited strong interparticle plasmonic coupling. This AuNP-mediated strategy offers new opportunities to drive macroscopic self-assembly and to fabricate well-defined nanophotonic materials and devices.

  9. Completing the nuclear reaction puzzle of the nucleosynthesis of 92Mo

    Science.gov (United States)

    Tveten, G. M.; Spyrou, A.; Schwengner, R.; Naqvi, F.; Larsen, A. C.; Eriksen, T. K.; Bello Garrote, F. L.; Bernstein, L. A.; Bleuel, D. L.; Crespo Campo, L.; Guttormsen, M.; Giacoppo, F.; Görgen, A.; Hagen, T. W.; Hadynska-Klek, K.; Klintefjord, M.; Meyer, B. S.; Nyhus, H. T.; Renstrøm, T.; Rose, S. J.; Sahin, E.; Siem, S.; Tornyi, T. G.

    2016-08-01

    One of the greatest questions for modern physics to address is how elements heavier than iron are created in extreme astrophysical environments. A particularly challenging part of that question is the creation of the so-called p -nuclei, which are believed to be mainly produced in some types of supernovae. The lack of needed nuclear data presents an obstacle in nailing down the precise site and astrophysical conditions. In this work, we present for the first time measurements on the nuclear level density and average γ strength function of 92Mo. State-of-the-art p -process calculations systematically underestimate the observed solar abundance of this isotope. Our data provide stringent constraints on the 91Nb(p ,γ )92Mo reaction rate, which is the last unmeasured reaction in the nucleosynthesis puzzle of 92Mo. Based on our results, we conclude that the 92Mo abundance anomaly is not due to the nuclear physics input to astrophysical model calculations.

  10. Desain Pembelajaran Bangun Datar Menggunakan Fable “Dog Catches Cat” And Puzzle Tangram Di Kelas II SD

    Directory of Open Access Journals (Sweden)

    Lisnani Lisnani

    2013-06-01

    Full Text Available Tujuan penelitian ini adalah mengembangkan kemampuan berpikir kreatif matematis siswa dalam pengenalan dan pengelompokkan bangun datar melalui fable “dog catches cat”, puzzle tangram, dan kreasi origami. Metode yang digunakan adalah design research terdiri dari tiga tahap, yaitu: preliminary, design experiment (pilot experiment dan teaching experiment, dan analysis retrospective.  Penelitian ini mengembangkan hasil pembelajaran tentang bangun datar melalui serangkaian aktivitas, prosedur, dan strategi bagi siswa dalam menemukan kemampuan berpikir kreatif melalui Pendekatan Pendidikan Matematika Realistik Indonesia (PMRI melalui konteks tangram melalui fable “dog catches cat”. Puzzle tangram, dan kreasi origami menjadi starting point materi pengenalan dan pengelompokkan bangun datar. Hasil dari penelitian ini berupa learning trajectory pada masing-masing aktivitas yaitu: 1 Aktivitas 1, siswa mengenal berbagai bentuk bangun datar melalui penggunaan fable. 2 Aktivitas 2, siswa mampu menyebutkan dan mengelompokkan berbagai bangun datar melalui puzzle tangram. 3 Aktivitas 3, membentuk dan mengelompokkan bangun datar dan terbentuk suatu kreasi baru berupa kucing, anjing, dan lainnya.The purpose of this research is to develop mathematical creative thinking abilities and grouping students in the introduction of a flat wake through the fable “dog catches paint " , tangram puzzles, and origami creations. The method used is the research design consists of three stages: preliminary, design of experiments (pilot experiments and teaching experiments, and a retrospective analysis. This study develops learning outcomes on a flat wake through a series of activities, procedures, and strategies for students in finding creative thinking abilities through Realistic Mathematics Education Approach Indonesia (PMRI through tangram context through fable “dog catches the paint “. Tangram puzzles, and origami creations become the starting point and the

  11. Two approaches towards the flavour puzzle. Dynamical minimal flavour violation and warped extra dimensions

    Energy Technology Data Exchange (ETDEWEB)

    Albrecht, Michaela E.

    2010-08-16

    The minimal-flavour-violating (MFV) hypothesis considers the Standard Model (SM) Yukawa matrices as the only source of flavour violation. In this work, we promote their entries to dynamical scalar spurion fields, using an effective field theory approach, such that the maximal flavour symmetry (FS) of the SM gauge sector is formally restored at high energy scales. The non-vanishing vacuum expectation values of the spurions induce a sequence of FS breaking and generate the observed hierarchy in the SM quark masses and mixings. The fact that there exists no explanation for it in the SM is known as the flavour puzzle. Gauging the non-abelian subgroup of the spontaneously broken FS, we interpret the associated Goldstone bosons as the longitudinal degrees of freedom of the corresponding massive gauge bosons. Integrating out the heavy Higgs modes in the Yukawa spurions leads directly to flavour-changing neutral currents (FCNCs) at tree level. The coefficients of the effective four-quark operators, resulting from the exchange of heavy flavoured gauge bosons, strictly follow the MFV principle. On the other hand, the Goldstone bosons associated with the global abelian symmetry group behave as weakly coupled axions which can be used to solve the strong CP problem within a modified Peccei-Quinn formalism. Models with a warped fifth dimension contain five-dimensional (5D) fermion bulk mass matrices in addition to their 5D Yukawa matrices, which thus represent an additional source of flavour violation beyond MFV. They can address the flavour puzzle since their eigenvalues allow for a different localisation of the fermion zero mode profiles along the extra dimension which leads to a hierarchy in the effective four-dimensional (4D) Yukawa matrices. At the same time, the fermion splitting introduces non-universal fermion couplings to Kaluza-Klein (KK) gauge boson modes, inducing tree-level FCNCs. Within a Randall-Sundrum model with custodial protection (RSc model) we carefully work

  12. Biophysical Puzzles Concerning Magnetite-Based Magnetoreception in the Common Nematode, Caenorhabditis elegans.

    Science.gov (United States)

    Kirschvink, J. L.; Kobayashi, A. K.

    2015-12-01

    A recent report demonstrating magnetotactic behavior in the nematode worm, C. elegans, presents two intriguing biophysical puzzles. Vidal-Gadea et al. (2015, DOI: 10.7554/eLife.07493) show that wild-type, well-fed populations from both Hemispheres migrate upwards when their soil environment is moist and wet, and downward when starved. Their data show that inverting the vertical component of the magnetic field reverses the migration direction, indicating that it is a magnetically polar (not axial) response. Also, the angle of magnetic migration varies with the inclination angle of the local geomagnetic field at the native site, minimizing travel time. This ancestral magnetic migration direction persists even when strains are taken to different areas. We note that only a single-domain ferromagnetic magnetoreceptor (e.g, magnetite) is capable of producing a polar magnetotactic response, and in support there is one report of magnetosomes in C. elegans (Cranfield et al., 2004;DOI 10.1098/rsbl.2004.0209). However, the polarity of a magnetosome is determined at the time it grows across the SPM/SD threshold, and the magnetic orientation will lock-in randomly unless biased by the strong field of adjacent magnetosomes. Hence, the persistence of a North or South seeking direction preference within these populations demands that stable magnetosome chains of fixed polarity must be transmitted from parents, to the eggs, to the larvae, and then to the new adults. This is similar to the non-genetic inheritance process by which populations of magnetotactic bacteria can maintain North- or South-seeking swimming preference. Furthermore, for a magnetotactic organism to maintain a consistent angle from the magnetic axis is not enough to make it go vertical; it would go in a cone. For them to go vertical as reported (or to deviate at their natal magnetic inclination) demands that they must have a separate gravity sensor with which to measure the inclination angle relative to the

  13. Cles: Etes-vous bon detective?; Enigmes grammaticales; Problemes policiers; Kidnapping (Keys: Are You a Good Detective?; Grammatical Puzzles; Detective Mysteries; Kidnapping).

    Science.gov (United States)

    Debyser, Francis; And Others

    1984-01-01

    Four sets of French classroom activities are presented: a mystery whose clues include two postcard messages; three puzzles with grammar-related clues; a mystery contained in three comic strip frames; and the solving of a kidnapping mystery. (MSE)

  14. Marriage \\`a-la-MOND: Baryonic dark matter in galaxy clusters and the cooling flow puzzle

    CERN Document Server

    Milgrom, Mordehai

    2007-01-01

    I start with a brief introduction to MOND phenomenology and its possible roots in cosmology--a notion that may turn out to be the most far reaching aspect of MOND. Next I discuss the implications of MOND for the dark matter (DM) doctrine: MOND's successes imply that baryons determine everything. For DM this would mean that the puny tail of leftover baryons in galaxies wags the hefty DM dog. This has to occur in many intricate ways, and despite the haphazard construction history of galaxies--a very tall order. I then concentrate on galaxy clusters in light of MOND, which still requires some yet undetected cluster dark matter, presumably in some baryonic form (CBDM). This CBDM might contribute to the heating of the x-ray emitting gas and thus alleviate the cooling-flow puzzle. MOND, qua theory of dynamics, does not directly enter the microphysics of the gas; however, it does force a new outlook on the role of DM in shaping the cluster gasdynamics: MOND tells us that the cluster DM is not cold dark matter, is no...

  15. Solving the 56Ni puzzle of magnetar-powered broad-lined type Ic supernovae

    CERN Document Server

    Wang, Ling-Jun; Xu, Dong; Wang, Shan-Qin; Dai, Zi-Gao; Wu, Xue-Feng; Wei, Jian-Yan

    2016-01-01

    Broad-lined type Ic supernovae (SNe Ic-BL) are of great importance because their association with long-duration gamma-ray bursts (LGRBs) holds the key to deciphering the central engine of LGRBs, which refrains from being unveiled despite decades of investigation. Among the two popularly hypothesized types of central engine, i.e., black holes and strongly magnetized neutron stars (magnetars), there is mounting evidence that the central engine of GRB-associated SNe (GRB-SNe) is rapidly rotating magnetars. Theoretical analysis also suggests that magnetars could be the central engine of SNe Ic-BL. What puzzled the researchers is the fact that light curve modeling indicates that as much as 0.2-0.5 solar mass of 56Ni was synthesized during the explosion of the SNe Ic-BL, which is unfortunately in direct conflict with current state-of-the-art understanding of magnetar-powered 56Ni synthesis. Here we propose a dynamic model of magnetar-powered SNe to take into account the acceleration of the ejecta by the magnetar, a...

  16. Genetic variation in the vulnerable and endemic Monkey Puzzle tree, detected using RAPDs.

    Science.gov (United States)

    Bekessy, Sarah A; Allnutt, T R; Premoli, A C; Lara, A; Ennos, R A; Burgman, M A; Cortes, M; Newton, A C

    2002-04-01

    Araucaria araucana (Monkey Puzzle), a southern South American tree species of exceptional cultural and economic importance, is of conservation concern owing to extensive historical clearance and current human pressures. Random amplified polymorphic DNA (RAPD) markers were used to characterise genetic heterogeneity within and among 13 populations of this species from throughout its natural range. Extensive genetic variability was detected and partitioned by analysis of molecular variance, with the majority of variation existing within populations (87.2%), but significant differentiation was recorded among populations (12.8%). Estimates of Shannon's genetic diversity and percent polymorphism were relatively high for all populations and provide no evidence for a major reduction in genetic diversity from historical events, such as glaciation. All pairwise genetic distance values derived from analysis of molecular variance (Phi(ST)) were significant when individual pairs of populations were compared. Although populations are geographically divided into Chilean Coastal, Chilean Andes and Argentinean regions, this grouping explained only 1.77% of the total variation. Within Andean groups there was evidence of a trend of genetic distance with increasing latitude, and clustering of populations across the Andes, suggesting postglacial migration routes from multiple refugia. Implications of these results for the conservation and use of the genetic resource of this species are discussed.

  17. The Puzzling Li-rich Red Giant Associated with NGC 6819

    CERN Document Server

    Carlberg, Joleen K; Cunha, Katia; Majewski, Steven R; Meszaros, Szabolcs; Shetrone, Matthew; Prieto, Carlos Allende; Bizyaev, Dmitry; Stassun, Keivan G; Fleming, Scott W; Zasowski, Gail; Hearty, Fred; Nidever, David L; Schneider, Donald P; Holtzman, Jon A; Frinchaboy, Peter M

    2015-01-01

    A Li-rich red giant star (2M19411367+4003382) recently discovered in the direction of NGC 6819 belongs to the rare subset of Li-rich stars that have not yet evolved to the luminosity bump, an evolutionary stage where models predict Li can be replenished. The currently favored model to explain Li enhancement in first-ascent red giants like 2M19411367+4003382 requires deep mixing into the stellar interior. Testing this model requires a measurement of 12C/13C, which is possible to obtain from APOGEE spectra. However, the Li-rich star also has abnormal asteroseismic properties that call into question its membership in the cluster, even though its radial velocity and location on color-magnitude diagrams are consistent with membership. To address these puzzles, we have measured a wide array of abundances in the Li-rich star and three comparison stars using spectra taken as part of the APOGEE survey to determine the degree of stellar mixing, address the question of membership, and measure the surface gravity. We con...

  18. The placebo puzzle: examining the discordant space between biomedical science and illness/healing.

    Science.gov (United States)

    Pohlman, Shawn; Cibulka, Nancy J; Palmer, Janice L; Lorenz, Rebecca A; SmithBattle, Lee

    2013-03-01

    The placebo response presents an enigma to biomedical science: how can 'inert' or 'sham' procedures reduce symptoms and produce physiological changes that are comparable to prescribed treatments? In this study, we examine this puzzle by explicating the discordant space between the prevailing biomedical paradigm, which focuses on a technical understanding of diagnosis and treatment, and a broader understanding of illness and healing as relational and embodied. Although biomedical achievements are impressive, the knowledge resulting from this paradigm is limited by its ontological and epistemological assumptions. When the body and world are objectified, illness meanings, therapeutic relationships, and healing practices are dismissed or distorted. In spite of a robust critique of the tenets of biomedicine for guiding practice, the biomedical paradigm retains a tenacious hold on evidence-based medicine and nursing, downplaying our clinical understanding of the sentient body, patients' life-worlds, and illness and healing. In reality, skilled nurses rely on multiple forms of knowledge in providing high-quality care to particular patients. Clinically wise nurses integrate their experience and knowledge of patients' priorities, fears, and illness trajectories along with biomedical findings to make astute judgments and promote health and healing.

  19. Physics and financial economics (1776-2014): puzzles, Ising and agent-based models

    Science.gov (United States)

    Sornette, Didier

    2014-06-01

    This short review presents a selected history of the mutual fertilization between physics and economics—from Isaac Newton and Adam Smith to the present. The fundamentally different perspectives embraced in theories developed in financial economics compared with physics are dissected with the examples of the volatility smile and of the excess volatility puzzle. The role of the Ising model of phase transitions to model social and financial systems is reviewed, with the concepts of random utilities and the logit model as the analog of the Boltzmann factor in statistical physics. Recent extensions in terms of quantum decision theory are also covered. A wealth of models are discussed briefly that build on the Ising model and generalize it to account for the many stylized facts of financial markets. A summary of the relevance of the Ising model and its extensions is provided to account for financial bubbles and crashes. The review would be incomplete if it did not cover the dynamical field of agent-based models (ABMs), also known as computational economic models, of which the Ising-type models are just special ABM implementations. We formulate the ‘Emerging Intelligence Market Hypothesis’ to reconcile the pervasive presence of ‘noise traders’ with the near efficiency of financial markets. Finally, we note that evolutionary biology, more than physics, is now playing a growing role to inspire models of financial markets.

  20. Low-voltage puzzle-like fractal microelectromechanial system variable capacitor suppressing pull-in

    KAUST Repository

    Elshurafa, Amro M.

    2012-10-01

    This Letter introduces an electrostatically actuated fractal MEMS variable capacitor that, by utilising the substrate, extends the tuning range (TR) beyond the theoretical limit of 1.5 as dictated by the pull-in phenomenon. The backbone concept behind the fractal varactor is to create a suspended movable plate possessing a specific fractal geometry, and to simultaneously create a bottom fixed plate complementary in shape to the top plate. Thus, when the top plate is actuated, it moves towards the bottom plate and fills the void present within the bottom plate without touching it akin to how puzzle pieces are assembled. Further, a reasonable horizontal separation is maintained between both the plates to avoid shorting. The electrostatic forces come from the capacitance formed between the top plate and bottom plate, and from the capacitance formed between the top plate and the doped substrate. The variable capacitor was fabricated in the PolyMUMPS process and provided a TR of 4.1 at 6 V, and its resonant frequency was in excess of 40 GHz.

  1. A Low-Resolution Spectroscopic Exploration of Puzzling OGLE Variable Stars

    CERN Document Server

    Pietrukowicz, P; Angeloni, R; di Mille, F; Soszynski, I; Udalski, A; Germana, C

    2015-01-01

    We present the results of a spectroscopic follow-up of various puzzling variable objects detected in the OGLE-III Galactic disk and bulge fields. The sample includes mainly short-period multi-mode pulsating stars that could not have been unambiguously classified as either delta Sct or beta Cep type stars based on photometric data only, also stars with irregular fluctuations mimicking cataclysmic variables and stars with dusty shells, and periodic variables displaying brightenings in their light curves that last for more than half of the period. The obtained low-resolution spectra show that all observed short-period pulsators are of delta Sct type, the stars with irregular fluctuations are young stellar objects, and the objects with regular brightenings are A type stars or very likely Ap stars with strong magnetic field responsible for the presence of bright caps around magnetic poles on their surface. We also took spectra of objects designated OGLE-GD-DSCT-0058 and OGLE-GD-CEP-0013. An estimated effective tem...

  2. Simultaneous Explanation of the $R_K$ and $R_{D^{(*)}}$ Puzzles: a Model Analysis

    CERN Document Server

    Bhattacharya, Bhubanjyoti; Guévin, Jean-Pascal; London, David; Watanabe, Ryoutaro

    2016-01-01

    $R_K$ and $R_{D^{(*)}}$ are two $B$-decay measurements that presently exhibit discrepancies with the SM. Recently, using an effective field theory approach, it was demonstrated that a new-physics model can simultaneously explain both the $R_K$ and $R_{D^{(*)}}$ puzzles. There are two UV completions that can give rise to the effective Lagrangian: (i) $VB$: a vector boson that transforms as an $SU(2)_L$ triplet, as in the SM, (ii) $U_1$: an $SU(2)_L$-singlet vector leptoquark. In this paper, we show that, in fact, $VB$ and $U_1$ can be distinguished experimentally. $VB$ also contributes to $\\tau \\to 3\\mu$, while $U_1$ does not. $VB$ predicts $1.9 \\times 10^{-10} \\le {\\cal B}(\\tau^-\\to\\mu^-\\mu^+\\mu^-) \\le 2.1 \\times 10^{-8}$, which should be measurable at Belle II (and perhaps LHCb). $\\tau \\to 3\\mu$ is therefore a smoking-gun signal of $VB$. For $U_1$, there are several observables that may point to this model. Perhaps the most interesting is the lepton-flavor-violating decay $\\Upsilon(3S) \\to \\mu \\tau$, which h...

  3. [What type of welfare policy promotes health?: the puzzling interrelation of economic and health inequality].

    Science.gov (United States)

    Hurrelmann, K; Richter, M; Rathmann, K

    2011-06-01

    In all highly developed countries, the overall health status of the population has significantly improved within the past 30 years. The most important reason for this is the increase in economic prosperity. Economic wealth, however, today is much more unequally distributed than it was 3 decades ago. Countries with relatively small disparities in the availability of material resources between socioeconomic groups, such as the Scandinavian countries, have better health outcomes on the population level. Health inequalities, however, have also reached a higher level than 30 years ago. As of today, we do not have convincing explanations for the interrelation of economic and health inequality. This paper gives an overview of existing research on a comparative basis. The research results are ambivalent. They show the puzzling result that the Scandinavian countries with their highly distributive welfare policy manage to achieve the comparatively highest level of economic, but not health, equity. Based on these results, we develop proposals for future research approaches. A central assumption is that in rich societies no longer only material, but more and more immaterial determinants are crucial for the formation of health inequality. The promotion of "salutogenic" self-management capabilities in socially disadvantaged groups is considered to be the central element in effective intervention strategies.

  4. Physics and financial economics (1776-2014): puzzles, Ising and agent-based models.

    Science.gov (United States)

    Sornette, Didier

    2014-06-01

    This short review presents a selected history of the mutual fertilization between physics and economics--from Isaac Newton and Adam Smith to the present. The fundamentally different perspectives embraced in theories developed in financial economics compared with physics are dissected with the examples of the volatility smile and of the excess volatility puzzle. The role of the Ising model of phase transitions to model social and financial systems is reviewed, with the concepts of random utilities and the logit model as the analog of the Boltzmann factor in statistical physics. Recent extensions in terms of quantum decision theory are also covered. A wealth of models are discussed briefly that build on the Ising model and generalize it to account for the many stylized facts of financial markets. A summary of the relevance of the Ising model and its extensions is provided to account for financial bubbles and crashes. The review would be incomplete if it did not cover the dynamical field of agent-based models (ABMs), also known as computational economic models, of which the Ising-type models are just special ABM implementations. We formulate the 'Emerging Intelligence Market Hypothesis' to reconcile the pervasive presence of 'noise traders' with the near efficiency of financial markets. Finally, we note that evolutionary biology, more than physics, is now playing a growing role to inspire models of financial markets.

  5. Geneva University - Measurement of the Lamb shift in muonic hydrogen: the proton radius puzzle

    CERN Multimedia

    2010-01-01

    GENEVA UNIVERSITY École de physique Département de physique nucléaire et corspusculaire 24, quai Ernest-Ansermet 1211 GENEVA 4 Tel: (022) 379 62 73 Fax: (022) 379 69 92 Wednesday 12 May 2010 PARTICLE PHYSICS SEMINAR at 17.00 hrs – Stückelberg Auditorium Measurement of the Lamb shift in muonic hydrogen: the proton radius puzzle Dr Aldo Antogninia , CREMA Collaboration, Max Planck Institute, Germany At the Paul Scherrer Institut, Switzerland, we have measured several 2S-2P transition frequencies in muonic hydrogen (µp) and deuterium (µd) by means of laser spectroscopy. This results in an order of magnitude improvement on the rms charge radius values of the proton and the deuteron. Additionally the Zemach radii and the deuteron polarizability are also inferred. The new proton radius value is deduced with a relative accuracy of 0.1% but strongly disagrees from CODATA. The origin of this discrepancy is not yet known. It may come from theo...

  6. The puzzling dynamical status of the core of the globular cluster NGC 6752

    CERN Document Server

    Ferraro, F R; Sabbi, E; Lagani, P; Rood, R T; D'Amico, N; Origlia, L

    2003-01-01

    We have used high resolution WFPC2-HST and ground based Wide Field images to determine the center of gravity and construct an extended radial density and brightness profile of the cluster NGC 6752 including, for the first time, detailed star counts in the very inner region. The barycenter of the 9 innermost X-ray sources detected by Chandra is located only 1.9" off the new center of gravity. Both the density and the brightness profile of the central region are best fitted by a double King model, suggesting that NGC 6752 is experiencing a post-core collapse "bounce". Taking advantage from our new optical data, we discuss the puzzling nature of the accelerations displayed by the innermost millisecond pulsars detected in this cluster. We discuss two possible origins to the accelerations: 1) the overall cluster gravitational potential which would require a central projected mass to light ratio of order 6-7 and the existence of a few thousand solar masses of low-luminosity matter within the inner 0.08 pc of NGC675...

  7. Learning and Memory Processes Following Cochlear Implantation:The Missing Piece of the Puzzle

    Directory of Open Access Journals (Sweden)

    David B. Pisoni

    2016-04-01

    Full Text Available At the present time, there is no question that cochlear implants work and often work very well in quiet listening conditions for many profoundly deaf children and adults. The speech and language outcomes data published over the last two decades document quite extensively the clinically significant benefits of cochlear implants. Although there now is a large body of evidence supporting the efficacy of cochlear implants as a medical intervention for profound hearing loss in both children and adults, there still remain a number of challenging unresolved clinical and theoretical issues that deal with the effectiveness of cochlear implants in individual patients that have not yet been successfully resolved. In this paper, we review recent findings on learning and memory, two central topics in the field of cognition that have been seriously neglected in research on cochlear implants. Our research findings on sequence learning, memory and organization processes, and retrieval strategies used in verbal learning and memory of categorized word lists suggests that basic domain-general learning abilities may be the missing piece of the puzzle in terms of understanding the cognitive factors that underlie the enormous individual differences and variability routinely observed in speech and language outcomes following cochlear implantation.

  8. Gravity does not exist a puzzle for the 21st century

    CERN Document Server

    Icke, Vincent

    2014-01-01

    Every scientific fact begins as an opinion about the unknown—a theory—that becomes fact as evidence piles up to support it. But what if two theories exist that correspond perfectly to observed phenomena and they cannot be reconciled with each other? Can theory become fact? Such is the dilemma in contemporary physics. In seeking to understand the mechanisms of the universe, physicists have arrived at two conflicting theories: one explains the mystery of gravity through a precise model of space and time, and the other explains the mystery of matter via the behavior of quantum particles. Each theory reigns in its own domain. But 13.8 billion years ago, when the universe first came into being, gravity and matter belonged to a single realm. Can these theories be united, and if so, what facts will be revealed? This, contends Vincent Icke, is the central puzzle facing physics in our century. Combining Icke’s expertise with a robust argument and intellectual playfulness, Gravity Does Not Exist makes a notorious...

  9. Hyperon puzzle and the RMF model with scaled hadron masses and coupling constants

    CERN Document Server

    Kolomeitsev, E E; Voskresensky, D N

    2015-01-01

    The equation of state of cold baryonic matter is studied within a relativistic mean-field model with hadron masses and coupling constants depending on a scalar field. We demonstrate that if the effective nucleon mass stops to decrease with a density increase at densities $n>n_*>n_0$, where $n_0$ is the nuclear saturation density, the equation of state stiffens for these densities and the limiting neutron star mass increases. The stabilization of the nucleon mass can be realised if in the equation of motion for the scalar mean-field there appear a term sharply varying in a narrow vicinity of the field value corresponding to the density $n_*$. We show several possible realizations of this mechanism getting sufficiently stiff equations of state. The appearance of hyperons in dense neutron star interiors is accounted for. The obtained equations of state remain sufficiently stiff if the reduction of the $\\phi$ meson mass is incorporated. Thereby, the hyperon puzzle can be resolved.

  10. Puzzles in modern biology. IV. Neurodegeneration, localized origin and widespread decay [version 1; referees: 2 approved

    Directory of Open Access Journals (Sweden)

    Steven A. Frank

    2016-10-01

    Full Text Available The motor neuron disease amyotrophic lateral sclerosis (ALS typically begins with localized muscle weakness. Progressive, widespread paralysis often follows over a few years. Does the disease begin with local changes in a small piece of neural tissue and then spread? Or does neural decay happen independently across diverse spatial locations? The distinction matters, because local initiation may arise by local changes in a tissue microenvironment, by somatic mutation, or by various epigenetic or regulatory fluctuations in a few cells. A local trigger must be coupled with a mechanism for spread. By contrast, independent decay across spatial locations cannot begin by a local change, but must depend on some global predisposition or spatially distributed change that leads to approximately synchronous decay. This article outlines the conceptual frame by which one contrasts local triggers and spread versus parallel spatially distributed decay. Various neurodegenerative diseases differ in their mechanistic details, but all can usefully be understood as falling along a continuum of interacting local and global processes. Cancer provides an example of disease progression by local triggers and spatial spread, setting a conceptual basis for clarifying puzzles in neurodegeneration. Heart disease also has crucial interactions between global processes, such as circulating lipid levels, and local processes in the development of atherosclerotic plaques. The distinction between local and global processes helps to understand these various age-related diseases.

  11. Theory of mind: a new perspective on the puzzle of belief ascription.

    Science.gov (United States)

    Airenti, Gabriella

    2015-01-01

    The concept of theory of mind (ToM) has considerably changed since its first proposal. The aim of first human studies was to understand how young children acquire the representation of others' mental states, in particular beliefs, and how they distinguish them from their own and from reality. The False Belief Task was designed to prove the acquisition of this capacity. According to children's performance in this test the acquisition of ToM has been attested at around 4 years of age. In last years it has been shown that using spontaneous response tasks also 15-month-old-children could attribute to an agent a false belief about the location of an object. These results have generated the puzzle of belief-ascription: Why do 3-year-old children fail the classical false belief tasks whereas much younger children show the correct expectation in the spontaneous response tasks? In this paper I shall argue that (i) infants and young children, when confronted with the two forms of false belief tasks do not face the same problem and (ii) behind the two testing situations there are different ways to understand theory of mind. I shall propose that what appears in infants is the natural human disposition to intersubjectivity.

  12. Leaf anatomical variation in Cephalaria laevigata (dipsacaceae under different ecological conditions

    Directory of Open Access Journals (Sweden)

    Jakovljević Ksenija

    2014-01-01

    Full Text Available The results of a multivariate morphometric study of leaf anatomical characters in different, geographically distant populations of the taxon Cephalaria laevigata from Serbia and Romania are presented with the aim to reveal the trends of population differentiation. Analyses were performed on a cross-section of 105 leaves collected from 10 populations. In order to establish the overall morphological variation and relationships between individuals from all populations, principal component analyses and canonical discriminant analysis were performed. Clustering analyses were carried out to explore whether the observed anatomical differences are a result of adaptive responses. Regression analysis was performed to identify the level of correlation between leaf anatomical characters and basic orographic, geological and bioclimatic habitat characteristics. Unexpectedly, in most of the characters there was discrepancy between leaf anatomy and climatic conditions, and the characters did not show significant regularities in the variability of their dimension neither in the vertical profile nor in relation to geological substrate. [Projekat Ministarstva nauke Republike Srbije, br. 173030

  13. New, puzzling insights from comparative myological studies on the old and unsolved forelimb/hindlimb enigma.

    Science.gov (United States)

    Diogo, Rui; Linde-Medina, Marta; Abdala, Virginia; Ashley-Ross, Miriam A

    2013-02-01

    Most textbooks and research reports state that the structures of the tetrapod forelimbs and hindlimbs are serial homologues. From this view, the main challenge of evolutionary biologists is not to explain the similarity between tetrapod limbs, but instead to explain why and how they have diverged. However, these statements seem to be related to a confusion between the serial homology of the vertebrate pelvic and pectoral appendages as a whole, and the serial homology of the specific soft- and hard-tissue structures of the tetrapod forelimbs and hindlimbs, leading to an even more crucial and puzzling question being overlooked: why are the skeletal and particularly the muscle structures of the forelimb and hindlimb actually so strikingly similar to each other? Herein we provide an updated discussion of these questions and test two main hypotheses: (i) that the similarity of the limb muscles is due to serial homology; and (ii) that tetrapods that use hindlimbs for a largely exclusive function (e.g. bipedalism in humans) exhibit fewer cases of similarity between forelimbs and hindlimbs than do quadrupedal species. Our review shows that of the 23 arm, forearm and hand muscles/muscle groups of salamanders, 18 (78%) have clear 'topological equivalents' in the hindlimb; in lizards, 14/24 (58%); in rats, 14/35 (40%); and in modern humans, 19/37 (51%). These numbers seem to support the idea that there is a plesiomorphic similarity and subsequent evolutionary divergence, but this tendency actually only applies to the three former quadrupedal taxa. Moreover, if one takes into account the total number of 'correspondences', one comes to a surprising and puzzling conclusion: in modern humans the number of forelimb muscles/muscle groups with clear 'equivalents' in the hindlimb (19) is substantially higher than in quadrupedal mammals such as rats (14), lizards (14) and even salamanders (18). These data contradict the hypothesis that divergent functions lead to divergent

  14. Marriage à-la-MOND: Baryonic dark matter in galaxy clusters and the cooling flow puzzle

    Science.gov (United States)

    Milgrom, Mordehai

    2008-05-01

    I start with a brief introduction to MOND phenomenology and its possible roots in cosmology—a notion that may turn out to be the most far reaching aspect of MOND. Next I discuss the implications of MOND for the dark matter (DM) doctrine: MOND's successes imply that baryons determine everything. For DM this would mean that the puny tail of leftover baryons in galaxies wags the hefty DM dog. This has to occur in many intricate ways, and despite the haphazard construction history of galaxies—a very tall order. I then concentrate on galaxy clusters in light of MOND, which still requires some yet undetected cluster dark matter, presumably in some baryonic form (CBDM). This CBDM might contribute to the heating of the X-ray emitting gas and thus alleviate the cooling flow puzzle. MOND, qua theory of dynamics, does not directly enter the microphysics of the gas; however, it does force a new outlook on the role of DM in shaping the cluster gas dynamics: MOND tells us that the cluster DM is not cold dark matter, is not so abundant, and is not expected in galaxies; it is thus not subject to constraints on baryonic DM in galaxies. The mass in CBDM required in a whole cluster is, typically, similar to that in hot gas, but is rather more centrally concentrated, totally dominating the core. The CBDM contribution to the baryon budget in the universe is thus small. Its properties, deduced for isolated clusters, are consistent with the observations of the "bullet cluster". Its kinetic energy reservoir is much larger than that of the hot gas in the core, and would suffice to keep the gas hot for many cooling times. Heating can be effected in various ways depending on the exact nature of the CBDM, from very massive black holes to cool, compact gas clouds.

  15. Solving the 56Ni Puzzle of Magnetar-powered Broad-lined Type IC Supernovae

    Science.gov (United States)

    Wang, Ling-Jun; Han, Yan-Hui; Xu, Dong; Wang, Shan-Qin; Dai, Zi-Gao; Wu, Xue-Feng; Wei, Jian-Yan

    2016-11-01

    Broad-lined Type Ic supernovae (SNe Ic-BL) are of great importance because their association with long-duration gamma-ray bursts (LGRBs) holds the key to deciphering the central engine of LGRBs, which refrains from being unveiled despite decades of investigation. Among the two popularly hypothesized types of central engine, i.e., black holes and strongly magnetized neutron stars (magnetars), there is mounting evidence that the central engine of GRB-associated SNe (GRB-SNe) is rapidly rotating magnetars. Theoretical analysis also suggests that magnetars could be the central engine of SNe Ic-BL. What puzzled the researchers is the fact that light-curve modeling indicates that as much as 0.2{--}0.5 {M}⊙ of 56Ni was synthesized during the explosion of the SNe Ic-BL, which is unfortunately in direct conflict with current state-of-the-art understanding of magnetar-powered 56Ni synthesis. Here we propose a dynamic model of magnetar-powered SNe to take into account the acceleration of the ejecta by the magnetar, as well as the thermalization of the injected energy. Assuming that the SN kinetic energy comes exclusively from the magnetar acceleration, we find that although a major fraction of the rotational energy of the magnetar is to accelerate the SN ejecta, a tiny fraction of this energy deposited as thermal energy of the ejecta is enough to reduce the needed 56Ni to 0.06 M ⊙ for both SN 1997ef and SN 2007ru. We therefore suggest that magnetars could power SNe Ic-BL in aspects both of energetics and of 56Ni synthesis.

  16. The Formation of Galaxies and Supermassive Black Holes: Insights and Puzzles

    Science.gov (United States)

    Somerville, Rachel S.

    2014-01-01

    Galaxies exist at a nexus of physical scales, molded by physics ranging from the “small” scales of star formation and accretion onto nuclear black holes, up to the very large scales of the cosmic web. It is this special property that makes galaxies so fascinating and so challenging to study, both observationally and theoretically. The past two decades have seen enormous progress in our understanding of how galaxies form and evolve. We have surveyed slices of the sky at many wavelengths, and built sophisticated models and simulations that attempt to capture the complex array of physics that influences galaxy evolution. We are only now coming into possession of large samples of galaxies for which we can study the internal structure as well as the large scale environment in detail, from the epoch of ‘cosmic high noon’ ( 2) to the present. At the same time, numerical simulations set within a cosmological framework have only recently succeeded in building galaxies with realistic internal structures. It has been known for several years that galaxies are growing in mass and radius, experiencing morphological transformation, and ‘downsizing’ their star formation activity over cosmic time. Now, new observations are painting a picture in which the internal structure of galaxies (size and morphology) is intimately linked with their star formation activity and formation history. There are hints that the co-evolution of supermassive black holes with their host galaxies may be the driving force behind these correlations - but this remains controversial. While cosmological simulations set within the hierarchical formation scenario of Cold Dark Matter currently offer a plausible story for interpreting these observations, many puzzles remain. I will review recent insights gleaned from deep multi-wavelength surveys and state-of-the-art theoretical models and simulations, as well as highlight the open questions and challenges for the future.

  17. New data and an old puzzle: the negative association between schizophrenia and rheumatoid arthritis

    Science.gov (United States)

    Lee, S Hong; Byrne, Enda M; Hultman, Christina M; Kähler, Anna; Vinkhuyzen, Anna AE; Ripke, Stephan; Andreassen, Ole A; Frisell, Thomas; Gusev, Alexander; Hu, Xinli; Karlsson, Robert; Mantzioris, Vasilis X; McGrath, John J; Mehta, Divya; Stahl, Eli A; Zhao, Qiongyi; Kendler, Kenneth S; Sullivan, Patrick F; Price, Alkes L; O’Donovan, Michael; Okada, Yukinori; Mowry, Bryan J; Raychaudhuri, Soumya; Wray, Naomi R; Byerley, William; Cahn, Wiepke; Cantor, Rita M; Cichon, Sven; Cormican, Paul; Curtis, David; Djurovic, Srdjan; Escott-Price, Valentina; Gejman, Pablo V; Georgieva, Lyudmila; Giegling, Ina; Hansen, Thomas F; Ingason, Andrés; Kim, Yunjung; Konte, Bettina; Lee, Phil H; McIntosh, Andrew; McQuillin, Andrew; Morris, Derek W; Nöthen, Markus M; O’Dushlaine, Colm; Olincy, Ann; Olsen, Line; Pato, Carlos N; Pato, Michele T; Pickard, Benjamin S; Posthuma, Danielle; Rasmussen, Henrik B; Rietschel, Marcella; Rujescu, Dan; Schulze, Thomas G; Silverman, Jeremy M; Thirumalai, Srinivasa; Werge, Thomas; Agartz, Ingrid; Amin, Farooq; Azevedo, Maria H; Bass, Nicholas; Black, Donald W; Blackwood, Douglas H R; Bruggeman, Richard; Buccola, Nancy G; Choudhury, Khalid; Cloninger, Robert C; Corvin, Aiden; Craddock, Nicholas; Daly, Mark J; Datta, Susmita; Donohoe, Gary J; Duan, Jubao; Dudbridge, Frank; Fanous, Ayman; Freedman, Robert; Freimer, Nelson B; Friedl, Marion; Gill, Michael; Gurling, Hugh; De Haan, Lieuwe; Hamshere, Marian L; Hartmann, Annette M; Holmans, Peter A; Kahn, René S; Keller, Matthew C; Kenny, Elaine; Kirov, George K; Krabbendam, Lydia; Krasucki, Robert; Lawrence, Jacob; Lencz, Todd; Levinson, Douglas F; Lieberman, Jeffrey A; Lin, Dan-Yu; Linszen, Don H; Magnusson, Patrik KE; Maier, Wolfgang; Malhotra, Anil K; Mattheisen, Manuel; Mattingsdal, Morten; McCarroll, Steven A; Medeiros, Helena; Melle, Ingrid; Milanova, Vihra; Myin-Germeys, Inez; Neale, Benjamin M; Ophoff, Roel A; Owen, Michael J; Pimm, Jonathan; Purcell, Shaun M; Puri, Vinay; Quested, Digby J; Rossin, Lizzy; Ruderfer, Douglas; Sanders, Alan R; Shi, Jianxin; Sklar, Pamela; St. Clair, David; Stroup, T Scott; Van Os, Jim; Visscher, Peter M; Wiersma, Durk; Zammit, Stanley; Bridges, S Louis; Choi, Hyon K; Coenen, Marieke JH; de Vries, Niek; Dieud, Philippe; Greenberg, Jeffrey D; Huizinga, Tom WJ; Padyukov, Leonid; Siminovitch, Katherine A; Tak, Paul P; Worthington, Jane; De Jager, Philip L; Denny, Joshua C; Gregersen, Peter K; Klareskog, Lars; Mariette, Xavier; Plenge, Robert M; van Laar, Mart; van Riel, Piet

    2015-01-01

    Background: A long-standing epidemiological puzzle is the reduced rate of rheumatoid arthritis (RA) in those with schizophrenia (SZ) and vice versa. Traditional epidemiological approaches to determine if this negative association is underpinned by genetic factors would test for reduced rates of one disorder in relatives of the other, but sufficiently powered data sets are difficult to achieve. The genomics era presents an alternative paradigm for investigating the genetic relationship between two uncommon disorders. Methods: We use genome-wide common single nucleotide polymorphism (SNP) data from independently collected SZ and RA case-control cohorts to estimate the SNP correlation between the disorders. We test a genotype X environment (GxE) hypothesis for SZ with environment defined as winter- vs summer-born. Results: We estimate a small but significant negative SNP-genetic correlation between SZ and RA (−0.046, s.e. 0.026, P = 0.036). The negative correlation was stronger for the SNP set attributed to coding or regulatory regions (−0.174, s.e. 0.071, P = 0.0075). Our analyses led us to hypothesize a gene-environment interaction for SZ in the form of immune challenge. We used month of birth as a proxy for environmental immune challenge and estimated the genetic correlation between winter-born and non-winter born SZ to be significantly less than 1 for coding/regulatory region SNPs (0.56, s.e. 0.14, P  = 0.00090). Conclusions: Our results are consistent with epidemiological observations of a negative relationship between SZ and RA reflecting, at least in part, genetic factors. Results of the month of birth analysis are consistent with pleiotropic effects of genetic variants dependent on environmental context. PMID:26286434

  18. Identifying sediment discontinuities and solving dating puzzles using monitoring and palaeolimnological records

    Science.gov (United States)

    Dong, Xuhui; Sayer, Carl D.; Bennion, Helen; Maberly, Stephen C.; Yang, Handong; Battarbee, Richard W.

    2016-12-01

    Palaeolimnological studies should ideally be based upon continuous, undisturbed sediment sequences with reliable chronologies. However for some lake cores, these conditions are not met and palaeolimnologists are often faced with dating puzzles caused by sediment disturbances in the past. This study chooses Esthwaite Water from England to illustrate how to identify sedimentation discontinuities in lake cores and how chronologies can be established for imperfect cores by correlation of key sediment signatures in parallel core records and with long-term monitoring data (1945-2003). Replicated short cores (ESTH1, ESTH7, and ESTH8) were collected and subjected to loss-on-ignition, radiometric dating (210Pb, 137Cs, and 14C), particle size, trace metal, and fossil diatom analysis. Both a slumping and a hiatus event were detected in ESTH7 based on comparisons made between the cores and the long-term diatom data. Ordination analysis suggested that the slumped material in ESTH7 originated from sediment deposited around 1805-1880 AD. Further, it was inferred that the hiatus resulted in a loss of sediment deposited from 1870 to 1970 AD. Given the existence of three superior 14C dates in ESTH7, ESTH1 and ESTH7 were temporally correlated by multiple palaeolimnological proxies for age-depth model development. High variability in sedimentation rates was evident, but good agreement across the various palaeolimnological proxies indicated coherence in sediment processes within the coring area. Differences in sedimentation rates most likely resulted from the natural morphology of the lake basin. Our study suggests that caution is required in selecting suitable coring sites for palaeolimnological studies of small, relatively deep lakes and that proximity to steep slopes should be avoided wherever possible. Nevertheless, in some cases, comparisons between a range of contemporary and palaeolimnological records can be employed to diagnose sediment disturbances and establish a chronology.

  19. Does the diffusion dark matter-dark energy interaction model solve cosmological puzzles?

    Science.gov (United States)

    Szydłowski, Marek; Stachowski, Aleksander

    2016-08-01

    We study dynamics of cosmological models with diffusion effects modeling dark matter and dark energy interactions. We show the simple model with diffusion between the cosmological constant sector and dark matter, where the canonical scaling law of dark matter (ρd m ,0a-3(t )) is modified by an additive ɛ (t )=γ t a-3(t ) to the form ρd m=ρd m ,0a-3(t )+ɛ (t ). We reduced this model to the autonomous dynamical system and investigate it using dynamical system methods. This system possesses a two-dimensional invariant submanifold on which the dark matter-dark energy (DM-DE) interaction can be analyzed on the phase plane. The state variables are density parameter for matter (dark and visible) and parameter δ characterizing the rate of growth of energy transfer between the dark sectors. A corresponding dynamical system belongs to a general class of jungle type of cosmologies represented by coupled cosmological models in a Lotka-Volterra framework. We demonstrate that the de Sitter solution is a global attractor for all trajectories in the phase space and there are two repellers: the Einstein-de Sitter universe and the de Sitter universe state dominating by the diffusion effects. We distinguish in the phase space trajectories, which become in good agreement with the data. They should intersect a rectangle with sides of Ωm ,0∈[0.2724 ,0.3624 ] , δ ∈[0.0000 ,0.0364 ] at the 95% CL. Our model could solve some of the puzzles of the Λ CDM model, such as the coincidence and fine-tuning problems. In the context of the coincidence problem, our model can explain the present ratio of ρm to ρd e, which is equal 0.457 6-0.0831+0.1109 at a 2 σ confidence level.

  20. The puzzling Hg family revisited: a comprehensive study based on density functional theory

    Directory of Open Access Journals (Sweden)

    C. Ambrosch-Draxl

    2006-09-01

    Full Text Available   We review theoretical investigations of high-temperature superconductors which have been performed by density functional theory. The main subject of our study is the Hg-based family of the superconducting cuprates, which demonstrates unusual and still puzzling properties. We show that the first-principles approach is able to describe the effects of chemical doping and pressure on the structural properties, the band structure, the ion charges, and the chemical bonds. We report on the origin of the optimal doping and present results on the inhomegeneity of the charge distribution and the concomitant splitting of the electronic bands and their contributions to the density of states. Due to their individual energy dependence, the role of the intrinsic inhomogeneities for superconductivity strongly depends on the energy and character of the quasiparticle mediating the Cooper pairing. The evolution of the electric field gradients with doping is analyzed and compared to nuclear resonance experiments. The calculated results can explain the origin of doping-induced effects observed either by local or macroscopic experimental probes. From a systematic study of the density of states by varying the doping concentration as well as applying pressure up to 15 GPa, and comparison with the measured critical temperatures, the coupling constant of the quasiparticle has been estimated to be of the order of one. Moreover, we show how density functional theory allows for the calculation of vibrational properties and phonon Raman scattering in the high-Tc cuprates. All results are quantitatively compared to experiment, and have revealed very good agreement.

  1. Social class and health: the puzzling counter-example of British South Asians.

    Science.gov (United States)

    Williams, R; Wright, W; Hunt, K

    1998-11-01

    British South Asians (with ancestry from the Indian subcontinent) provided a puzzling exception to the British class gradient in mortality during the 1970s. On the assumption that class gradients in health are produced mainly by gradients in standard of living, this might be due to a break in the relation of class to standard of living (change in class structure), or by a break in the relation of standard of living to patterns of health behaviour and health risk (change in class lifestyles). Data on these characteristics are available from the West of Scotland Twenty-07 Study, where 159 South Asians aged 30-40 (mean age 35) were sampled alongside 319 of the general population in Glasgow. As regards changes in class structure, results indicate that the underclass thesis, which suggests that ethnic minorities are forced into less eligible jobs or into a separate labour market or into unemployment, resulting in a standard of living below that of the general population, still holds good for British South Asians in categories from social class III non-manual downwards. It does not hold good for owners of small businesses, where Sikhs and Hindus in particular have a standard of living equivalent to general population counterparts. However, prosperity is not predictable from levels of education in the subcontinent and from this and other signs it appears that a wholesale redistribution of class chances is occurring among British South Asians, disrupting inter-and intra-generational continuities in the relation between class and standard of living. There is little sign of change in class lifestyles, i.e. in the relation between standard of living and health behaviour or health risk. As yet, though, the new distribution of standard of living is affecting patterns of health behaviour and health risk more strongly than symptom experience or chronic illness, suggesting that a class gradient in health will re-emerge.

  2. RNA-Puzzles Round II: assessment of RNA structure prediction programs applied to three large RNA structures.

    Science.gov (United States)

    Miao, Zhichao; Adamiak, Ryszard W; Blanchet, Marc-Frédérick; Boniecki, Michal; Bujnicki, Janusz M; Chen, Shi-Jie; Cheng, Clarence; Chojnowski, Grzegorz; Chou, Fang-Chieh; Cordero, Pablo; Cruz, José Almeida; Ferré-D'Amaré, Adrian R; Das, Rhiju; Ding, Feng; Dokholyan, Nikolay V; Dunin-Horkawicz, Stanislaw; Kladwang, Wipapat; Krokhotin, Andrey; Lach, Grzegorz; Magnus, Marcin; Major, François; Mann, Thomas H; Masquida, Benoît; Matelska, Dorota; Meyer, Mélanie; Peselis, Alla; Popenda, Mariusz; Purzycka, Katarzyna J; Serganov, Alexander; Stasiewicz, Juliusz; Szachniuk, Marta; Tandon, Arpit; Tian, Siqi; Wang, Jian; Xiao, Yi; Xu, Xiaojun; Zhang, Jinwei; Zhao, Peinan; Zok, Tomasz; Westhof, Eric

    2015-06-01

    This paper is a report of a second round of RNA-Puzzles, a collective and blind experiment in three-dimensional (3D) RNA structure prediction. Three puzzles, Puzzles 5, 6, and 10, represented sequences of three large RNA structures with limited or no homology with previously solved RNA molecules. A lariat-capping ribozyme, as well as riboswitches complexed to adenosylcobalamin and tRNA, were predicted by seven groups using RNAComposer, ModeRNA/SimRNA, Vfold, Rosetta, DMD, MC-Fold, 3dRNA, and AMBER refinement. Some groups derived models using data from state-of-the-art chemical-mapping methods (SHAPE, DMS, CMCT, and mutate-and-map). The comparisons between the predictions and the three subsequently released crystallographic structures, solved at diffraction resolutions of 2.5-3.2 Å, were carried out automatically using various sets of quality indicators. The comparisons clearly demonstrate the state of present-day de novo prediction abilities as well as the limitations of these state-of-the-art methods. All of the best prediction models have similar topologies to the native structures, which suggests that computational methods for RNA structure prediction can already provide useful structural information for biological problems. However, the prediction accuracy for non-Watson-Crick interactions, key to proper folding of RNAs, is low and some predicted models had high Clash Scores. These two difficulties point to some of the continuing bottlenecks in RNA structure prediction. All submitted models are available for download at http://ahsoka.u-strasbg.fr/rnapuzzles/.

  3. RNA-Puzzles Round II: assessment of RNA structure prediction programs applied to three large RNA structures

    Science.gov (United States)

    Miao, Zhichao; Adamiak, Ryszard W.; Blanchet, Marc-Frédérick; Boniecki, Michal; Bujnicki, Janusz M.; Chen, Shi-Jie; Cheng, Clarence; Chojnowski, Grzegorz; Chou, Fang-Chieh; Cordero, Pablo; Cruz, José Almeida; Ferré-D'Amaré, Adrian R.; Das, Rhiju; Ding, Feng; Dokholyan, Nikolay V.; Dunin-Horkawicz, Stanislaw; Kladwang, Wipapat; Krokhotin, Andrey; Lach, Grzegorz; Magnus, Marcin; Major, François; Mann, Thomas H.; Masquida, Benoît; Matelska, Dorota; Meyer, Mélanie; Peselis, Alla; Popenda, Mariusz; Purzycka, Katarzyna J.; Serganov, Alexander; Stasiewicz, Juliusz; Szachniuk, Marta; Tandon, Arpit; Tian, Siqi; Wang, Jian; Xiao, Yi; Xu, Xiaojun; Zhang, Jinwei; Zhao, Peinan; Zok, Tomasz; Westhof, Eric

    2015-01-01

    This paper is a report of a second round of RNA-Puzzles, a collective and blind experiment in three-dimensional (3D) RNA structure prediction. Three puzzles, Puzzles 5, 6, and 10, represented sequences of three large RNA structures with limited or no homology with previously solved RNA molecules. A lariat-capping ribozyme, as well as riboswitches complexed to adenosylcobalamin and tRNA, were predicted by seven groups using RNAComposer, ModeRNA/SimRNA, Vfold, Rosetta, DMD, MC-Fold, 3dRNA, and AMBER refinement. Some groups derived models using data from state-of-the-art chemical-mapping methods (SHAPE, DMS, CMCT, and mutate-and-map). The comparisons between the predictions and the three subsequently released crystallographic structures, solved at diffraction resolutions of 2.5–3.2 Å, were carried out automatically using various sets of quality indicators. The comparisons clearly demonstrate the state of present-day de novo prediction abilities as well as the limitations of these state-of-the-art methods. All of the best prediction models have similar topologies to the native structures, which suggests that computational methods for RNA structure prediction can already provide useful structural information for biological problems. However, the prediction accuracy for non-Watson–Crick interactions, key to proper folding of RNAs, is low and some predicted models had high Clash Scores. These two difficulties point to some of the continuing bottlenecks in RNA structure prediction. All submitted models are available for download at http://ahsoka.u-strasbg.fr/rnapuzzles/. PMID:25883046

  4. Definition of a visuospatial dimension as a step forward in the diagnostic puzzle of nonverbal learning disability.

    Science.gov (United States)

    Poletti, Michele

    2016-03-17

    Although clinically recognized for almost 50 years, the categorical distinction of specific learning disabilities due to an impairment of the nonverbal domain (nonverbal learning disability [NLD]) is still debated and controversial. Unsolved issues involve theoretical models, diagnostic criteria, rehabilitative interventions, and moderator factors. These issues are briefly overviewed to sustain the need for a shift toward dimensional approaches, as suggested by research domain criteria, as a step forward in the diagnostic puzzle of NLD. With this aim, a visuospatial dimension, or spectrum, is proposed, and then clinical conditions that may fit with its impaired side are systemized, while specifying in which conditions a visuospatial impairment may be considered an NLD.

  5. Comparative cytogenetic analysis of diploid and hexaploid Chenopodium album Agg

    Directory of Open Access Journals (Sweden)

    Bożena Kolano

    2011-01-01

    Full Text Available Two cytotypes of Chenopodium album, diploid (2n=2x=18 and hexaploid (2n=6x=54, were analysed using flow cytometry and a FISH experiment. The genome size was indicated as 1.795 pg for the diploid and 3.845 pg for the hexaploid plants which suggested genome downsizing in the evolution of hexaploid cytotype. Double FISH with 25S rDNA and 5S rDNA allowed three to five homologue chromosome pairs to be distinguished depending on the cytotype. The Variation in size and number of rDNA sites between the polyploid C. album and its putative diploid ancestor indicated that rDNA loci underwent rearrangements after polyploidization. Flow cytometry measurements of the relative nuclear DNA content in the somatic tissue of C. album revealed extensive endopolyploidization resulting in tissues comprising a mixture of cells with a different DNA content (from 2C to 32C in varying proportions. The pattern of endopolyploidy was characteristic for the developmental stage of the plant and for the individual organ. Polysomaty was not observed in the embryo tissues however endopolyploidization had taken place in most tested organs of seedlings. The endopolyploidy in diploid and hexaploid C. album was compared to find any relationship between the pattern of polysomaty and polyploidy level in this species. This revealed that polyploid plants showed a decline in the number of endocycles as well as in the frequency of endopolyploidy cells compared to diploid plants.

  6. Rechtsmissbrauch durch „AGG-Hopping“ / Steffen Krieger

    Index Scriptorium Estoniae

    Krieger, Steffen

    2016-01-01

    Euroopa Kohtu otsusest, mis puudutab töökohale kandideerija staatust eesmärgiga esitada kahju hüvitamise nõudeid kui teda ei valita tööle ja sellise teguviisi käsitlemist õiguse kuritarvitamisena. Vt. ka lk. 699-700

  7. The Three-Color and Two-Color Tantrix(TM) Rotation Puzzle Problems are NP-Complete via Parsimonious Reductions

    CERN Document Server

    Baumeister, Dorothea

    2007-01-01

    Holzer and Holzer (Discrete Applied Mathematics 144(3):345--358, 2004) proved the Tantrix(TM) rotation puzzle problem with four colors NP-complete. Baumeister and Rothe (MCU 2007) modified their construction to achieve a parsimonious reduction from satisfiability to this problem. Since parsimonious reductions preserve the number of solutions, it follows that the unique version of the four-color Tantrix(TM) rotation puzzle problem is DP-complete under randomized reductions. In this paper, we study the three-color and the two-color Tantrix(TM) rotation puzzle problem. Restricting the number of allowed colors to three (respectively, to two) reduces the set of available Tantrix(TM) tiles from 56 to 14 (respectively, to 8). We prove that both the three-color and the two-color Tantrix(TM) rotation puzzle problem is NP-complete, which answers a question raised by Holzer and Holzer in the affirmative. Since both these reductions are parsimonious, it follows that both the unique three-color and the unique two-color Ta...

  8. Double-pionic fusion of nuclear systems and the "ABC" effect: approaching a puzzle by exclusive and kinematically complete measurements.

    Science.gov (United States)

    Bashkanov, M; Bargholtz, C; Berłowski, M; Bogoslawsky, D; Calén, H; Clement, H; Demiroers, L; Doroshkevich, E; Duniec, D; Ekström, C; Fransson, K; Geren, L; Gustafsson, L; Höistad, B; Ivanov, G; Jacewicz, M; Jiganov, E; Johansson, T; Khakimova, O; Keleta, S; Koch, I; Kren, F; Kullander, S; Kupść, A; Lindberg, K; Marciniewski, P; Meier, R; Morosov, B; Pauly, C; Pettersson, H; Petukhov, Y; Povtorejko, A; Pricking, A; Ruber, R J M Y; Schönning, K; Scobel, W; Shwartz, B; Skorodko, T; Sopov, V; Stepaniak, J; Tegner, P-E; Thörngren-Engblom, P; Tikhomirov, V; Turowiecki, A; Wagner, G J; Wolke, M; Zabierowski, J; Zartova, I; Złomanczuk, J

    2009-02-06

    The ABC effect-a puzzling low-mass enhancement in the pipi invariant mass spectrum, first observed by Abashian, Booth, and Crowe-is well known from inclusive measurements of two-pion production in nuclear fusion reactions. Here we report on the first exclusive and kinematically complete measurements of the most basic double-pionic fusion reaction pn-->dpi;{0}pi;{0} at beam energies of 1.03 and 1.35 GeV. The measurements, which have been carried out at CELSIUS-WASA, reveal the ABC effect to be a (pipi)_{I=L=0} channel phenomenon associated with both a resonancelike energy dependence in the integral cross section and the formation of a DeltaDelta system in the intermediate state. A corresponding simple s-channel resonance ansatz provides a surprisingly good description of the data.

  9. Double-Pionic Fusion of Nuclear Systems and the ``ABC'' Effect: Approaching a Puzzle by Exclusive and Kinematically Complete Measurements

    Science.gov (United States)

    Bashkanov, M.; Bargholtz, C.; Berłowski, M.; Bogoslawsky, D.; Calén, H.; Clement, H.; Demiroers, L.; Doroshkevich, E.; Duniec, D.; Ekström, C.; Fransson, K.; Geren, L.; Gustafsson, L.; Höistad, B.; Ivanov, G.; Jacewicz, M.; Jiganov, E.; Johansson, T.; Khakimova, O.; Keleta, S.; Koch, I.; Kren, F.; Kullander, S.; Kupść, A.; Lindberg, K.; Marciniewski, P.; Meier, R.; Morosov, B.; Pauly, C.; Pettersson, H.; Petukhov, Y.; Povtorejko, A.; Pricking, A.; Ruber, R. J. M. Y.; Schönning, K.; Scobel, W.; Shwartz, B.; Skorodko, T.; Sopov, V.; Stepaniak, J.; Tegner, P.-E.; Thörngren-Engblom, P.; Tikhomirov, V.; Turowiecki, A.; Wagner, G. J.; Wolke, M.; Zabierowski, J.; Zartova, I.; Złomanczuk, J.

    2009-02-01

    The ABC effect—a puzzling low-mass enhancement in the ππ invariant mass spectrum, first observed by Abashian, Booth, and Crowe—is well known from inclusive measurements of two-pion production in nuclear fusion reactions. Here we report on the first exclusive and kinematically complete measurements of the most basic double-pionic fusion reaction pn→dπ0π0 at beam energies of 1.03 and 1.35 GeV. The measurements, which have been carried out at CELSIUS-WASA, reveal the ABC effect to be a (ππ)I=L=0 channel phenomenon associated with both a resonancelike energy dependence in the integral cross section and the formation of a ΔΔ system in the intermediate state. A corresponding simple s-channel resonance ansatz provides a surprisingly good description of the data.

  10. Double-Pionic Fusion of Nuclear Systems and the ABCEffect -- Aproaching a Puzzle by Exclusive and Kinematically Complete Measurements

    CERN Document Server

    Bashkanov, M; Berlowski, M; Bogoslawsky, D; Calén, H; Clement, H; Demiroers, L; Doroshkevich, E; Duniec, D; Ekström, C; Fransson, K; Geren, L; Gustafsson, L; Höistad, B; Ivanov, G; Jacewicz, M; Jiganov, E; Johansson, T; Khakimova, O; Keleta, S; Koch, I; Kren, F; Kullander, Sven; Kupsc, A; Lindberg, K; Marciniewski, P; Meier, R; Morosov, B; Pauly, C; Pettersson, H; Petukhov, Yu P; Povtorejko, A; Pricking, A; Ruber, R J M Y; Schonning, K; Scobel, W; Shwartz, B; Skorodko, T; Sopov, V; Stepaniak, J; Tegner, P -E; Thorngren-Engblom, P; Tikhomirov, V; Turowiecki, A; Wagner, G J; Wolke, M; Zabierowski, J; Zartova, I; Zlomanczuk, Yu

    2008-01-01

    The ABC effect - a puzzling low-mass enhancement in the $\\pi\\pi$ invariant mass spectrum - is well-known from inclusive measurements of two-pion production in nuclear fusion reactions. Here we report on first exclusive and kinematically complete measurements of solid statistics, which have been carried out at CELSIUS-WASA for the fusion reactions leading to d and $^3$He in the final states. These measurements reveal the ABC effect to be a $\\sigma$ channel phenomenon associated with the formation of an isoscalar dibaryonic resonance in connection with a $\\Delta\\Delta$ system in the intermediate state. A corresponding theoretical ansatz provides an adequate description both for the differential distributions and for the resonance-like energy dependence of the integral cross section.

  11. 相对财富与股票溢价之谜%Relative Wealth and the Equity Premium Puzzle

    Institute of Scientific and Technical Information of China (English)

    毕先萍; 肖争艳; 李正友

    2004-01-01

    Mehra和Prescott(1985)提出著名的股票溢价之谜(Equity Premium Puzzle):合理的相对风险规避系数,不能解释美国S&P500指数的收益率为什么比无风险债券的收益率高出6个百分点.本文提出了一个基于相对财富的资产定价模型,其中代表性投资者的效用函数不但依赖于消费,还依赖于投资者的绝对财富,及社会平均财富.本文使用该模型,解释了股票溢价之谜.

  12. Triángulos cuadrados y cruces cuadradas: algunos puzzles geométricos de H. E. Dudeney

    Directory of Open Access Journals (Sweden)

    Francisco Pérez Arribas

    2012-04-01

    Full Text Available Henry Ernest Dudeney (1857-1930 fue un autor inglés, conocido por los retos y acertijos matemáticos que publicó a lo largo de su vida en distintas revistas y que han sido recopilados posteriormente en distintos libros. Algunos de sus más de 200 retos tienen interesantes propiedades geométricas que pueden ser exploradas y mostradas con claridad, usando herramientas informáticas actuales. Este artículo presenta y analiza dos puzzles (disecciones de gran atractivo geométrico: la transformación de un triángulo equilátero en un cuadrado, y la transformación de una curiosa cruz en un cuadrado.

  13. RED DWARF DYNAMO RAISES PUZZLE OVER INTERIORS OF LOWEST-MASS STARS

    Science.gov (United States)

    2002-01-01

    -years away in the constellation Aquila. Gliese 752A is a red dwarf that is one-third the mass of the Sun and slightly more than half its diameter. By contrast, VB10 is physically smaller than the planet Jupiter and only about nine percent the mass of our Sun. This very faint star is near the threshold of the lowest possible mass for a true star (.08 solar masses), below which nuclear fusion processes cannot take place according to current models. A team led by Linsky used Hubble's Goddard High Resolution Spectrograph (GHRS) to make a one-hour long exposure of VB10 on October 12, 1994. No detectable ultraviolet emission was seen until the last five minutes, when bright emission was detected in a flare. Though the star's normal surface temperature is 4,500 degrees Fahrenheit, Hubble's GHRS detected a sudden burst of 270,000 degrees Fahrenheit in the star's outer atmosphere. Linsky attributes this rapid heating to the presence of an intense, but unstable, magnetic field. THE INTERIOR WORKINGS OF A STELLAR DYNAMO Before the Hubble observation, astronomers thought magnetic fields in stars required the same dynamo process which creates magnetic fields on the Sun. In the classic solar model, heat generated by nuclear fusion reactions at the star's center escapes through a radiative zone just outside the core. The heat travels from the radiative core to the star's surface through a convection zone. In this region, heat bubbles to the surface by motions similar to boiling in a pot of water. Dynamos, which accelerate electrons to create magnetic forces, operate when the interior of a star rotates faster than the surface. Recent studies of the Sun indicate its convective zone rotates at nearly the same rate at all depths. This means the solar dynamo must operate in the more rapidly rotating radiative core just below the convective zone. The puzzle is that stars below 20 percent the mass of our Sun do not have radiative cores, but instead transport heat from their core through

  14. ESA's Rosetta mission and the puzzles that Hale-Bopp left behind

    Science.gov (United States)

    1997-04-01

    kilometres with a set of remote-sensing instruments. As the spacecraft moves around the nucleus at a very leisurely walking pace, other onboard instruments will analyse the dust and vapours, which will emanate from Comet Wirtanen with ever-increasing vigour as the Sun's rays warm it. Rosetta will drop a lander on to the comet's surface, for close inspection of its physical condition and chemical composition. The lander is a venture led by Germany, France and Italy, with participation from Austria, Finland, Hungary, Poland and the UK. As a box packed with scientific instruments and standing on three legs, the lander will be capable of anchoring itself to one spot and drilling into the surface. It may also be able to hop like a flea to visit another part of the nucleus. A combination of solar energy and electric batteries will enable operations to last for several months. "The combination of Rosetta in orbit around the comet and the lander on its surface is very powerful from a scientific point of view," says Gerhard Schwehm, ESA's project scientist for Rosetta. "We shall watch Comet Wirtanen brewing up like a volcano as it feels the heat of the Sun. In place of hazy impressions of the nucleus of a comet half hidden by its dust clouds, we shall see all the details with unprecedented clarity." Unanswered questions During and after the 1986 appearance of Halley's Comet, comet science made great progress. More recent comets have revealed important secrets to ESA's Infrared Space Observatory and to other space telescopes examining them at wavelengths unobservable from the Earth. Yet basic questions about comets remain unanswered. Just as the Rosetta Stone was the key that unlocked the meaning of Egyptian hieroglyphs, so the Rosetta spacecraft is intended to decipher the meaning of comets and their role in the origin and history of the Solar System. Here are a few of the main puzzles. * What does a comet weigh? Guesses about the density of cometary material vary widely, and only an

  15. Puzzling out the proton radius puzzle

    Energy Technology Data Exchange (ETDEWEB)

    Mihovilovič, M.; Merkel, H.; Weber, A. [Institut für Kernphysik, Johannes Gutenberg-Universität Mainz, Johann-Joachim-Becher-Weg 45, 55128 Mainz (Germany)

    2016-01-22

    The discrepancy between the proton charge radius extracted from the muonic hydrogen Lamb shift measurement and the best present value obtained from the elastic scattering experiments, remains unexplained and represents a burning problem of today’s nuclear physics: after more than 50 years of research the radius of a basic constituent of matter is still not understood. This paper presents a summary of the best existing proton radius measurements, followed by an overview of the possible explanations for the observed inconsistency between the hydrogen and the muonic-hydrogen data. In the last part the upcoming experiments, dedicated to remeasuring the proton radius, are described.

  16. Puzzling out the proton radius puzzle

    Directory of Open Access Journals (Sweden)

    Mihovilovič Miha

    2014-01-01

    Full Text Available The discrepancy between the proton charge radius extracted from the muonic hydrogen Lamb shift measurement and the best present value obtained from the elastic scattering experiments, remains unexplained and represents a burning problem of today’s nuclear physics: after more than 50 years of research the radius of a basic constituent of matter is still not understood. This paper presents a summary of the best existing proton radius measurements, followed by an overview of the possible explanations for the observed inconsistency between the hydrogen and the muonic-hydrogen data. In the last part the upcoming experiments, dedicated to remeasuring the proton radius, are described.

  17. The puzzle of the 1996 Bárdarbunga, Iceland, earthquake: no volumetric component in the source mechanism

    Science.gov (United States)

    Tkalcic, Hrvoje; Dreger, Douglas S.; Foulger, Gillian R.; Julian, Bruce R.

    2009-01-01

    A volcanic earthquake with Mw 5.6 occurred beneath the Bárdarbunga caldera in Iceland on 29 September 1996. This earthquake is one of a decade-long sequence of  events at Bárdarbunga with non-double-couple mechanisms in the Global Centroid Moment Tensor catalog. Fortunately, it was recorded well by the regional-scale Iceland Hotspot Project seismic experiment. We investigated the event with a complete moment tensor inversion method using regional long-period seismic waveforms and a composite structural model. The moment tensor inversion using data from stations of the Iceland Hotspot Project yields a non-double-couple solution with a 67% vertically oriented compensated linear vector dipole component, a 32% double-couple component, and a statistically insignificant (2%) volumetric (isotropic) contraction. This indicates the absence of a net volumetric component, which is puzzling in the case of a large volcanic earthquake that apparently is not explained by shear slip on a planar fault. A possible volcanic mechanism that can produce an earthquake without a volumetric component involves two offset sources with similar but opposite volume changes. We show that although such a model cannot be ruled out, the circumstances under which it could happen are rare.

  18. The puzzle of Italian rice origin and evolution: determining genetic divergence and affinity of rice germplasm from Italy and Asia.

    Science.gov (United States)

    Cai, Xingxing; Fan, Jing; Jiang, Zhuxi; Basso, Barbara; Sala, Francesco; Spada, Alberto; Grassi, Fabrizio; Lu, Bao-Rong

    2013-01-01

    The characterization of genetic divergence and relationships of a set of germplasm is essential for its efficient applications in crop breeding and understanding of the origin/evolution of crop varieties from a given geographical region. As the largest rice producing country in Europe, Italy holds rice germplasm with abundant genetic diversity. Although Italian rice varieties and the traditional ones in particular have played important roles in rice production and breeding, knowledge concerning the origin and evolution of Italian traditional varieties is still limited. To solve the puzzle of Italian rice origin, we characterized genetic divergence and relationships of 348 rice varieties from Italy and Asia based on the polymorphisms of microsatellite fingerprints. We also included common wild rice O. rufipogon as a reference in the characterization. Results indicated relatively rich genetic diversity (H(e) = 0.63-0.65) in Italian rice varieties. Further analyses revealed a close genetic relationship of the Italian traditional varieties with those from northern China, which provides strong genetic evidence for tracing the possible origin of early established rice varieties in Italy. These findings have significant implications for the rice breeding programs, in which appropriate germplasm can be selected from a given region and utilized for transferring unique genetic traits based on its genetic diversity and evolutionary relationships.

  19. Oil puzzle in Chinese stock market%中国股票市场的石油效应之谜

    Institute of Scientific and Technical Information of China (English)

    董坤; 谢海滨; 汪寿阳

    2012-01-01

    本文对股票市场是否具有可预测性进行探讨,通过石油价格的变动,进而预测上海证券交易所综合指数(SSEC)的收益率.检验结果显示,自2003年后,上证综指收益率存在显著的石油效应,这种中国所特有的石油效应之谜,既不能用有效市场假说来解释,也无法被信息反应不足假说所解释.%This paper reinvestigates the predictability of equity market index return of Chinese Shanghai Stock Exchange Composite index (SSEC) using the changes in oil prices. We find a significant oil effect on the predictability of SSEC returns after the year 2003. The effect can neither be explained by the efficient market hypothesis nor be explained by the information under-reaction hypothesis, which presents a Chinese oil puzzle.

  20. A Puzzle-Based Genetic Algorithm with Block Mining and Recombination Heuristic for the Traveling Salesman Problem

    Institute of Scientific and Technical Information of China (English)

    Pei-Chann Chang; Wei-Hsiu Huang; Zhen-Zhen Zhang

    2012-01-01

    In this research,we introduce a new heuristic approach using the concept of ant colony optimization (ACO)to extract patterns from the chromosomes generated by previous generations for solving the generalized traveling salesman problem.The proposed heuristic is composed of two phases.In the first phase the ACO technique is adopted to establish an archive consisting of a set of non-overlapping blocks and of a set of remaining cities (nodes) to be visited.The second phase is a block recombination phase where the set of blocks and the rest of cities are combined to form an artificial chromosome.The generated artificial chromosomes (ACs) will then be injected into a standard genetic algorithm (SGA) to speed up the convergence.The proposed method is called "Puzzle-Based Genetic Algorithm" or "p-ACGA".We demonstrate that p-ACGA performs very well on all TSPLIB problems,which have been solved to optimality by other researchers.The proposed approach can prevent the early convergence of the genetic algorithm (GA) and lead the algorithm to explore and exploit the search space by taking advantage of the artificial chromosomes.

  1. Black hole quasi-normal modes: the "electrons" of quantum gravity? Implications for the black hole information puzzle

    CERN Document Server

    Corda, Christian

    2015-01-01

    Some recent important results on black hole (BH) quantum physics concerning the BH effective state and the natural correspondence between Hawking radiation and BH quasi-normal modes (QNMs) are reviewed, clarified and refined. Such a correspondence permits to naturally interpret QNMs as quantum levels in a semi-classical model. This is a model of BH somewhat similar to the historical semi-classical model of the structure of a hydrogen atom introduced by Bohr in 1913. In a certain sense, QNMs represent the "electron" which jumps from a level to another one and the absolute values of the QNMs frequencies "triggered" by emissions (Hawking radiation) and absorption of particles represent the energy "shells" of the "gravitational hydrogen atom". Important consequences on the BH information puzzle are discussed. In fact, it is shown that the time evolution of this "Bohr-like BH model" obeys to a time dependent Schr\\"odinger equation which permits the final BH state to be a pure quantum state instead of a mixed one. ...

  2. Recovering the Genetic Identity of an Extinct-in-the-Wild Species: The Puzzling Case of the Alagoas Curassow

    Science.gov (United States)

    Costa, Mariellen C.; Oliveira, Paulo R. R.; Davanço, Paulo V.; de Camargo, Crisley; Laganaro, Natasha M.; Azeredo, Roberto A.; Simpson, James; Silveira, Luis F.

    2017-01-01

    The conservation of many endangered taxa relies on hybrid identification, and when hybrids become morphologically indistinguishable from the parental species, the use of molecular markers can assign individual admixture levels. Here, we present the puzzling case of the extinct in the wild Alagoas Curassow (Pauxi mitu), whose captive population descends from only three individuals. Hybridization with the Razor-billed Curassow (P. tuberosa) began more than eight generations ago, and admixture uncertainty affects the whole population. We applied an analysis framework that combined morphological diagnostic traits, Bayesian clustering analyses using 14 microsatellite loci, and mtDNA haplotypes to assess the ancestry of all individuals that were alive from 2008 to 2012. Simulated data revealed that our microsatellites could accurately assign an individual a hybrid origin until the second backcross generation, which permitted us to identify a pure group among the older, but still reproductive animals. No wild species has ever survived such a severe bottleneck, followed by hybridization, and studying the recovery capability of the selected pure Alagoas Curassow group might provide valuable insights into biological conservation theory. PMID:28056082

  3. Event-by-Event Hydrodynamics +Jet Energy Loss: A Solution to the RA A⊗v2 Puzzle

    Science.gov (United States)

    Noronha-Hostler, Jacquelyn; Betz, Barbara; Noronha, Jorge; Gyulassy, Miklos

    2016-06-01

    High pT>10 GeV elliptic flow, which is experimentally measured via the correlation between soft and hard hadrons, receives competing contributions from event-by-event fluctuations of the low-pT elliptic flow and event-plane angle fluctuations in the soft sector. In this Letter, a proper account of these event-by-event fluctuations in the soft sector, modeled via viscous hydrodynamics, is combined with a jet-energy-loss model to reveal that the positive contribution from low-pT v2 fluctuations overwhelms the negative contributions from event-plane fluctuations. This leads to an enhancement of high-pT>10 GeV elliptic flow in comparison to previous calculations and provides a natural solution to the decade-long high-pT RA A⊗v2 puzzle. We also present the first theoretical calculation of high-pT v3, which is shown to be compatible with current LHC data. Furthermore, we discuss how short-wavelength jet-medium physics can be deconvoluted from the physics of soft, bulk event-by-event flow observables using event-shape engineering techniques.

  4. The puzzle of Italian rice origin and evolution: determining genetic divergence and affinity of rice germplasm from Italy and Asia.

    Directory of Open Access Journals (Sweden)

    Xingxing Cai

    Full Text Available The characterization of genetic divergence and relationships of a set of germplasm is essential for its efficient applications in crop breeding and understanding of the origin/evolution of crop varieties from a given geographical region. As the largest rice producing country in Europe, Italy holds rice germplasm with abundant genetic diversity. Although Italian rice varieties and the traditional ones in particular have played important roles in rice production and breeding, knowledge concerning the origin and evolution of Italian traditional varieties is still limited. To solve the puzzle of Italian rice origin, we characterized genetic divergence and relationships of 348 rice varieties from Italy and Asia based on the polymorphisms of microsatellite fingerprints. We also included common wild rice O. rufipogon as a reference in the characterization. Results indicated relatively rich genetic diversity (H(e = 0.63-0.65 in Italian rice varieties. Further analyses revealed a close genetic relationship of the Italian traditional varieties with those from northern China, which provides strong genetic evidence for tracing the possible origin of early established rice varieties in Italy. These findings have significant implications for the rice breeding programs, in which appropriate germplasm can be selected from a given region and utilized for transferring unique genetic traits based on its genetic diversity and evolutionary relationships.

  5. Visual Puzzles, Figure Weights, and Cancellation: Some Preliminary Hypotheses on the Functional and Neural Substrates of These Three New WAIS-IV Subtests.

    Science.gov (United States)

    McCrea, Simon M; Robinson, Thomas P

    2011-01-01

    In this study, five consecutive patients with focal strokes and/or cortical excisions were examined with the Wechsler Adult Intelligence Scale and Wechsler Memory Scale-Fourth Editions along with a comprehensive battery of other neuropsychological tasks. All five of the lesions were large and typically involved frontal, temporal, and/or parietal lobes and were lateralized to one hemisphere. The clinical case method was used to determine the cognitive neuropsychological correlates of mental rotation (Visual Puzzles), Piagetian balance beam (Figure Weights), and visual search (Cancellation) tasks. The pattern of results on Visual Puzzles and Figure Weights suggested that both subtests involve predominately right frontoparietal networks involved in visual working memory. It appeared that Visual Puzzles could also critically rely on the integrity of the left temporoparietal junction. The left temporoparietal junction could be involved in temporal ordering and integration of local elements into a nonverbal gestalt. In contrast, the Figure Weights task appears to critically involve the right temporoparietal junction involved in numerical magnitude estimation. Cancellation was sensitive to left frontotemporal lesions and not right posterior parietal lesions typical of other visual search tasks. In addition, the Cancellation subtest was sensitive to verbal search strategies and perhaps object-based attention demands, thereby constituting a unique task in comparison with previous visual search tasks.

  6. What cognitive strategies do orangutans (Pongo pygmaeus) use to solve a trial-unique puzzle-tube task incorporating multiple obstacles?

    Science.gov (United States)

    Tecwyn, Emma C; Thorpe, Susannah K S; Chappell, Jackie

    2012-01-01

    Apparently sophisticated behaviour during problem-solving is often the product of simple underlying mechanisms, such as associative learning or the use of procedural rules. These and other more parsimonious explanations need to be eliminated before higher-level cognitive processes such as causal reasoning or planning can be inferred. We presented three Bornean orangutans with 64 trial-unique configurations of a puzzle-tube to investigate whether they were able to consider multiple obstacles in two alternative paths, and subsequently choose the correct direction in which to move a reward in order to retrieve it. We were particularly interested in how subjects attempted to solve the task, namely which behavioural strategies they could have been using, as this is how we may begin to elucidate the cognitive mechanisms underpinning their choices. To explore this, we simulated performance outcomes across the 64 trials for various procedural rules and rule combinations that subjects may have been using based on the configuration of different obstacles. Two of the three subjects solved the task, suggesting that they were able to consider at least some of the obstacles in the puzzle-tube before executing action to retrieve the reward. This is impressive compared with the past performances of great apes on similar, arguably less complex tasks. Successful subjects may have been using a heuristic rule combination based on what they deemed to be the most relevant cue (the configuration of the puzzle-tube ends), which may be a cognitively economical strategy.

  7. Large-scale impacts of multiple co-occurring invaders on monkey puzzle forest regeneration, native seed predators and their ecological interactions

    Directory of Open Access Journals (Sweden)

    José L. Tella

    2016-04-01

    Full Text Available Most ecosystems of the world are being increasingly invaded by a variety of alien species. However, little is known about the combined ecological impacts of multiple co-occurring invaders. We assessed the impact of a community of exotic mammals (five domestic and four wild on forests of monkey puzzle (Araucaria araucana, a globally endangered tree restricted to ca 400 km2 on the slopes of the Andes in Chile and Argentina. Seeds of monkey puzzles provide food during winter to a small community of native mice and Austral parakeets (Enicognathus ferrugineus. We recorded the number of uneaten seeds and the number of young seedlings at the end of winter under 516 female monkey puzzle trees located across the species’ distribution, and identified the signals of native and exotic species that visited the under-canopy of each tree. Moreover, we studied the diet and foraging behavior of Austral parakeets to explore the potential indirect effects of exotic mammals through the disruption of a key ecosystem service (seed dispersal supposedly provided by parakeets. All but one tree were visited by at least one seed predator species. Austral parakeets and mice predated seeds from 85% and at least 45% of the trees, respectively, and both the number of remaining seeds and seedlings were significantly larger when only parakeets or mice predated seeds than when exotic mammals also visited the trees. At least 90% of trees were visited by one or more exotic species, and the number of seeds and seedlings dropped drastically when at least two and four exotic species visited the tree, respectively. Austral parakeets mostly foraged on monkey puzzle trees during the winter period and dispersed their seeds in most feeding instances once seeds fell to the ground. The proliferation of exotic mammals may reduce the populations of native seed-predators in the long-term as well as the regeneration of monkey puzzle forests, directly through a reduction of seed availability

  8. 基于"挖洞"思想的数独游戏生成算法%Sudoku Puzzles Generating:From Easy to Evil

    Institute of Scientific and Technical Information of China (English)

    薛源海; 蒋彪彬; 李永卓

    2009-01-01

    Sudoku puzzle becomes worldwide popular among many players in different intellectual levels. The task is to devise an algorithm that creates Sudoku puzzles in varying level of difficulty. With the analysis of the game rules, we first define the difficulty level from four aspects as: total given cells, distribution of given cells and complexity of enumerating search. By the guidance from the definition of difficulty level, the algorithm for generating puzzles is developed with the "dig-hole" strategy on a valid grid. Thus, the algorithm developed in two steps: to create a valid grid by Las Vegas algorithm, and then to generating puzzles by erasing some digits using five operators : · Determine a sequence of digging holes according to the desirable difficulty level, · Set two restrictions to guide the distribution of given cells, · Judge whether a puzzle being dug out has a unique solution by a solver built using Depth-First Search, · Add pruning technique to avoid digging an invalid cell, and · Perform propagating at a dug-out puzzle to raise the diversity of the output puzzle. Using our developed algorithm, we generate Sudoku puzzles in any five difficulty levels.The difficulty level of output puzzles can be adjusted by a desirable difficulty value input by players. The complexity of the algorithms in space and time is analyzed to demonstrate the effectiveness of the algorithms. Our main contributions in exploring the "dig-hole" strategy are summarized as following three works: to do a massive research on the sequence of digging holes and how it affects the algorithm to create a evil-level puzzle with minimal given cells, to invent a skill for judging the solution's uniqueness of a puzzle being dug out by the reduction to absurdity, and to reduce the computational time by avoiding backtracking to an explored cell and refilling an empty cell.%设计一个算法用以生成各种难度等级的数独题,通过对游戏规则的分析,首先从以下三个方面

  9. APRENDER JUGANDO CON "TEJIDOS PRECOLOMBINOS" MEDIANTE ROMPECABEZAS VIRTUALES LEARN BY PLAYING WITH "PRE-COLUMBIAN TEXTILES" THROUGH VIRTUAL PUZZLES

    Directory of Open Access Journals (Sweden)

    Diego Aracena Pizarro

    2008-09-01

    Full Text Available Este trabajo presenta un ambiente multimedia de rompecabezas sobre tejidos precolombinos de gran complejidad ornamental, expuestos en el Museo Arqueológico San Miguel de Azapa, Arica-Chile. El rompecabezas permite interaccionar de manera más entretenida y didáctica, con el objetivo de que la facilidad del uso del software permita aprender jugando, observando los intrincados símbolos y signos precolombinos que de otra manera pasan desapercibidos por no formar parte del ideario de los estudiantes actuales. El software se evaluó con alumnos de enseñanza básica y media de establecimientos educacionales de la ciudad, con el objetivo de complementar sus estudios a las asignaturas de historia que contienen temática prehispánica. Esta representación educacional fue implementada con herramienta Flash multimedia, con el propósito de estimular la parte creativa de los estudiantes y de abrir un mundo de juegos complementarios referentes al mismo tema, con la filosofía de aprender jugando.This paper presents a multimedia environment puzzle about Pre-Columbian textiles exhibiting ornamental complexities, found in the Archeological Museum San Miguel de Azapa, Arica-Chile. The software allow for an enjoyable and didactic interactive way of learning by playing, giving the users the opportunity of identifying intricate pre-Columbian symbols and signals, that otherwise would be unnoticed. The software was tested with schoolboys of ages 12 to 16 years old, from schools in Arica, with the purpose of complementing their studies in History courses containing Pre-hispanic topics. This educational software was implemented with Multimedia Flash Tool, so as to stimulate the creativity of the students, opening a world of complementary games with the philosophy of "learning by playing".

  10. The Infinity Puzzle - The story of the Higgs Boson:From QED to the LHC via Higgs and the Gang of Six

    CERN Document Server

    CERN. Geneva

    2013-01-01

    Rutherford and Bohr discovered the nuclear atom 100 years ago. Roughly 50 years ago a theory of this basic structure of matter was inspired by the work of Peter Higgs and others. In July 2012 the discovery "beyond reasonable doubt" of Higgs's boson, and the experimental proof of the theory, was announced and speculations about Nobel prizes mushroomed. The Economist said of Frank Close's book, The Infinity Puzzle (OUP,2012): "The Nobel Committee would be well advised to read Mr Close’s book before making their decision." This pedagogic talk reviews the ideas and the history, and assesses how the credits should be shared. The conclusions may not be what you anticipate

  11. Amino Acid Crossword Puzzle

    Science.gov (United States)

    Sims, Paul A.

    2011-01-01

    Learning the 20 standard amino acids is an essential component of an introductory course in biochemistry. Later in the course, the students study metabolism and learn about various catabolic and anabolic pathways involving amino acids. Learning new material or concepts often is easier if one can connect the new material to what one already knows;…

  12. Puzzles on grammatical gender

    NARCIS (Netherlands)

    Roodenburg, J.; Hulk, A.

    2008-01-01

    This article explores the link between the notion of "neuter" gender and default in Dutch, a language that does not make the familiar distinction between masculine and feminine nouns, but opposes non-neuter nouns to neuter nouns. In trying to extend to Dutch the analysis of "neuter" as a default pro

  13. Striking Oil: Another Puzzle

    NARCIS (Netherlands)

    G. Driesprong (Gerben); B. Jacobsen (Ben); B. Maat (Benjamin)

    2003-01-01

    textabstractWe find that changes in oil prices strongly predict future stock market returns in many countries in the world. In our thirty year sample of monthly data for developed stock markets, we find statistically significant predictability in 12 out of the 18 countries and in a world market inde

  14. Solving the Power Puzzle

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    China’s power supply and consumption system needs market-oriented reform Under constant pressure from power companies, the National Development and Reform Commission (NDRC) has agreed to raise electricity prices. The move comes despite the fact that price hikes could have a negative trickle down effect hindering the Central Government’s efforts to rein in inflation.

  15. The Format Puzzle

    DEFF Research Database (Denmark)

    Knudsen, Bo Nissen

    been supplemented by an official cadastral name database as well as a database of medieval settlement names. And in order to obtain some consistency, new information categories such as name generics have been added, geo-coding from the cadastral database has been applied to the names from the printed...... series when possible – and a web-tool for manual geo-coding of the remaining names has been developed....

  16. The Puzzle of Coherence

    DEFF Research Database (Denmark)

    Andersen, Anne Bendix; Frederiksen, Kirsten; Beedholm, Kirsten

    2016-01-01

    Background During the past decade, politicians and healthcare providers have strived to create a coherent healthcare system across primary and secondary healthcare sectors in Denmark. Nevertheless, elderly patients with chronic diseases (EPCD) continue to report experiences of poor-quality care...... to an acute care ward to discharge and later in meetings with healthcare providers in general practice, outpatient clinics, home care and physiotherapy. Furthermore, field observations were conducted in general practice, home care and rehabilitation settings. Research design An explorative design based...... on an interactionistic approach was used. As a consequence, the focus of data collection is the production of meaning happening between human beings in social interaction in the field of cross-sectorial collaboration. Research questions The research questions reflect the interactionistic approach as they concentrate...

  17. The Puzzle of Coherence

    DEFF Research Database (Denmark)

    Andersen, Anne Bendix; Frederiksen, Kirsten; Beedholm, Kirsten;

    2016-01-01

    of coherence in treatment and patient pathways. The aim of our study is to explore the role of health care providers in furthering coherence. Our ambition is to identify areas for improvement or change of collaborative practice between health care providers in municipalities, hospitals and general practice...... initiatives in health care. The present study will generate new, valuable insight into the areas of cross-sectorial health care collaboration. Our findings may facilitate change in current practice and improve the quality and coherence in patient pathways of EPCD. The findings of this study will be useful...

  18. The Birth Order Puzzle.

    Science.gov (United States)

    Zajonc, R. B.; And Others

    1979-01-01

    Discusses the controversy of the relationship between birth order and intellectual performance through a detailed evaluation of the confluence model which assumes that the rate of intellectual growth is a function of the intellectual environment within the family and associated with the special circumstances of last children. (CM)

  19. The Tradable Shares Puzzle

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    A huge number of restricted shares were made tradable in March in the mainland stock market,testing the capability of the fragile capital market Ping An of China has been made the main scapegoat of this year s stock market plunge.A month after its refinancing plan announcement- equivalent to recreating a new Ping An- its 3.12 billion restricted shares were made tradable on March 3,accounting for almost

  20. China: moral puzzles.

    Science.gov (United States)

    Xu, T M

    1990-01-01

    This is the first of a set of three articles concerned with "bioethics on the Pacific Rim." The author, vice president of Beijing Medical University and vice chairman of the Beijing Academic Association for Morality, identifies population control, euthanasia, and the allocation of health care resources as bioethical issues of current interest in his country. Population policy in China is grounded in public welfare arguments. The idea of a right to choose one's death is found in Chinese philosophy, although Chinese legal experts believe that euthanasia is not compatible with present criminal, civil, or family law. Allocation of health resources remains a problem in China, even throughout the free medical service that serves a small portion, largely composed of government employees, of the country's population of 1.08 billion.

  1. Forex Reserve Puzzle

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    China faces pressure of preserving the value of its $3 trillion foreign exchange reserves While already under pressure to revalue its currency,the yuan,against the U.S.dollar,China also faces the challenge of stifling vast losses to its foreign exchange reserve,mostly denominated in U.S.dollars.These losses to foreign exchange

  2. The Puzzle of Coherence

    DEFF Research Database (Denmark)

    Andersen, Anne Bendix; Frederiksen, Kirsten; Beedholm, Kirsten;

    2016-01-01

    in general practice, outpatient clinics, home care and physiotherapy. Furthermore, field observations are conducted in general practice, home care and rehabilitation settings. Perspectives Knowledge about the practice of cross-sectorial collaboration is crucial to the future planning of collaborating...... initiatives in health care. The present study will generate new, valuable insight into the areas of cross-sectorial health care collaboration. Our findings may facilitate change in current practice and improve the quality and coherence in patient pathways of EPCD. The findings of this study will be useful...

  3. Quantum top secret. The solution of the quantum puzzle. Metamorphosis of a picture of world; Quantum top secret. Die Loesung des Quantenraetsels. Metamorphose eines Weltbildes

    Energy Technology Data Exchange (ETDEWEB)

    Wingert, M.

    2008-07-01

    Many physicists believe that because of unexplained causes, which must anyway be concerned with the quantum puzzle and the mysterious consciousness, it would be no more possible to understand the real structure of the reality - this subtle smiling of the nature, which irritates the physicists since 100 years and the disturbed the theoretical physics so much that they threw the towel. Since nature is considered as absurd, strange, and crazy - and quantum theory as very complicated. But in reality the basic experiments are of a touching simplicity, which seems only completely unintelligible in the picture of world of mechanics. For these experiments show that the concept of body of mechanics and the body conceptions of the thinking cannot at all match the structure of nature. If this is objectively taken notice of without doubting on the existence of a reality, the experiments show the real, unveiled face of the nature. Light and matter must then consist of fields, which can themselves divide by non-mechanical way, so with wholeness, comparable only with cell division and branching processes in biology. Either it is completely crazy - or the only logic interpretation, which hitherto only no physicist risked to think. For these experiments disprove the atom and elementary-particle hypothesis, the picture of world of mechanics, and also the quantum-mechanical interpretation - and indeed uniquely. This knowledge could break the Gordian knot, solve the quantum puzzle, and also give away the secret of the thinking spirit.

  4. X-ray illumination of globular cluster puzzles. [globular cluster X ray sources as clues to Milky Way Galaxy age and evolution

    Science.gov (United States)

    Lightman, A. P.; Grindlay, J. E.

    1982-01-01

    Globular clusters are thought to be among the oldest objects in the Galaxy, and provide, in this connection, important clues for determining the age and process of formation of the Galaxy. The present investigation is concerned with puzzles relating to the X-ray emission of globular clusters, taking into account questions regarding the location of X-ray emitting clusters (XEGC) unusually near the galactic plane and/or galactic center. An adopted model is discussed for the nature, formation, and lifetime of X-ray sources in globular clusters. An analysis of the available data is conducted in connection with a search for correlations between binary formation time scales, central relaxation times, galactic locations, and X-ray emission. The positive correlation found between distance from galactic center and two-body binary formation time for globular clusters, explanations for this correlation, and the hypothesis that X-ray sources in globular clusters require binary star systems provide a possible explanation of the considered puzzles.

  5. Putting the whole grain puzzle together: health benefits associated with whole grains--summary of American Society for Nutrition 2010 Satellite Symposium.

    Science.gov (United States)

    Jonnalagadda, Satya S; Harnack, Lisa; Liu, Rui Hai; McKeown, Nicola; Seal, Chris; Liu, Simin; Fahey, George C

    2011-05-01

    The symposium "Putting the Whole Grain Puzzle Together: Health Benefits Associated with Whole Grains" sponsored by the ASN brought together researchers to review the evidence regarding the health benefits associated with whole grains. Current scientific evidence indicates that whole grains play an important role in lowering the risk of chronic diseases, such as coronary heart disease, diabetes, and cancer, and also contribute to body weight management and gastrointestinal health. The essential macro- and micronutrients, along with the phytonutrients present in whole grains, synergistically contribute to their beneficial effects. Current evidence lends credence to the recommendations to incorporate whole grain foods into a healthy diet and lifestyle program. The symposium also highlighted the need for further research to examine the role of whole grain foods in disease prevention and management to gain a better understanding of their mechanisms of action.

  6. Investigation for the puzzling abundance pattern of the neutron-capture elements in the ultra metal-poor star: CS 30322-023

    CERN Document Server

    Cui, W Y; Ma, K; Zhang, L

    2007-01-01

    The s-enhanced and very metal-poor star CS 30322-023 shows a puzzling abundance pattern of the neutron-capture elements, i.e. several neutron-capture elements such as Ba, Pb etc. show enhancement, but other neutron-capture elements such as Sr, Eu etc. exhibit deficient with respect to iron. The study to this sample star could make people gain a better understanding of s- and r-process nucleosynthesis at low metallicity. Using a parametric model, we find that the abundance pattern of the neutron-capture elements could be best explained by a star that was polluted by an AGB star and the CS 30322-023 binary system formed in a molecular cloud which had never been polluted by r-process material. The lack of r-process material also indicates that the AGB companion cannot have undergone a type-1.5 supernova, and thus must have had an initial mass below 4.0M$_\\odot$, while the strong N overabundance and the absence of a strong C overabundance indicate that the companion's initial mass was larger than 2.0M$_\\odot$. Th...

  7. Coping Strategies for the Puzzles in Poverty Identification of College Students%大学生贫困认定中的困惑及应对策略

    Institute of Scientific and Technical Information of China (English)

    张青林

    2011-01-01

    做好高校学生的贫困补助工作十分重要,它体现了国家对经济困难家庭的关爱,体现一种社会公平。但是高校学生的贫困认定是一项十分模糊的工作,有许多令人困惑的东西。文章从大学生贫困认定的标准、贫困认定中的隐私保护、贫困认定中的诚信问题三个方面进行探讨,希望能为大学生贫困认定工作提供借鉴。%The poverty identification of college students is animportant job.It reflects the social justice and the care and helpof our state to the poverty families.However,the poverty identification of college students is a very obscure work.And thereare many confusing things.This paper discusses three puzzling problems in the poverty identification of collegestudents,that is,the standards of poverty recognized,the privacy protec-tion and the credibility of the poverty students.It could prov-ide a means to the poverty identification of college students.

  8. bar{B}_{d,s} → D^{*}_{d,s} V and bar{B}_{d,s}^* → D_{d,s} V decays in QCD factorization and possible puzzles

    Science.gov (United States)

    Chang, Qin; Chen, Ling-Xin; Zhang, Yun-Yun; Sun, Jun-Feng; Yang, Yue-Ling

    2016-10-01

    Motivated by the rapid development of heavy-flavor experiments, phenomenological studies of nonleptonic bar{B}_{d,s} → D^{*}_{d,s} V and bar{B}_{d,s}^* → D_{d,s} V (V=ρ ,K^*) decays are performed within the framework of QCD factorization. Relative to the previous work, the QCD corrections to the transverse amplitudes are evaluated at next-to-leading order. The theoretical predictions of the observables are updated. For the measured bar{B}_{d,s} → D^{*}_{d,s} V decays, the tensions between theoretical results and experimental measurements, i.e. the "R_{ds}V puzzle" and "D^{*} V (or R_{V/ℓ bar{ν }_ℓ }) puzzle", are presented after detailed analyses. For the bar{B}_{d,s}^* → D_{d,s} V decays, they have relatively large branching fractions of the order ≳ O(10^{-9}) and are in the scope of Belle-II and LHCb experiments. Moreover, they also provide a way to crosscheck the possible puzzles mentioned above through the similar ratios R_{ds}^' V} and R_{V/ℓ bar{ν }_ℓ }^' }. More refined experimental measurements and theoretical efforts are required to confirm or refute such two anomalies.

  9. Unraveling a 146 years old taxonomic puzzle: validation of Malabar snakehead, species-status and its relevance for channid systematics and evolution.

    Directory of Open Access Journals (Sweden)

    Allen Benziger

    Full Text Available BACKGROUND: The Malabar snakehead Channa diplogramma is one of the most enigmatic and least understood species within the family Channidae, which comprise one of the most important groups of freshwater food fish in tropical Asia. Since its description from peninsular India in 1865, it has remained a taxonomic puzzle with many researchers questioning its validity, based on its striking similarity with the South East Asian C. micropeltes. In this study, we assessed the identity of the Malabar snakehead, C. diplogramma, using morphological and molecular genetic analyses, and also evaluated its phylogenetic relationships and evolutionary biogeography. METHODOLOGY/PRINCIPAL FINDINGS: The morphometric and meristic analysis provided conclusive evidence to separate C. diplogramma and C. micropeltes as two distinct species. Number of caudal fin rays, lateral line scales, scales below lateral line; total vertebrae, pre-anal length and body depth were the most prominent characters that can be used to differentiate both the species. Channa diplogramma also shows several ontogenic color phases during its life history, which is shared with C. micropeltes. Finally, the genetic distance between both species for the partial mitochondrial 16S rRNA and COI sequences is also well above the intra-specific genetic distances of any other channid species compared in this study. CONCLUSIONS/SIGNIFICANCE: The current distribution of C. diplogramma and C. micropeltes is best explained by vicariance. The significant variation in the key taxonomic characters and the results of the molecular marker analysis points towards an allopatric speciation event or vicariant divergence from a common ancestor, which molecular data suggests to have occurred as early as 21.76 million years ago. The resurrection of C. diplogramma from the synonymy of C. micropeltes has hence been confirmed 146 years after its initial description and 134 years after it was synonymised, establishing it is

  10. Disentangling Puzzles of Spatial Scales and Participation in Environmental Governance-The Case of Governance Re-scaling Through the European Water Framework Directive.

    Science.gov (United States)

    Newig, Jens; Schulz, Daniel; Jager, Nicolas W

    2016-12-01

    This article attempts to shed new light on prevailing puzzles of spatial scales in multi-level, participatory governance as regards the democratic legitimacy and environmental effectiveness of governance systems. We focus on the governance re-scaling by the European Water Framework Directive, which introduced new governance scales (mandated river basin management) and demands consultation of citizens and encourages 'active involvement' of stakeholders. This allows to examine whether and how re-scaling through deliberate governance interventions impacts on democratic legitimacy and effective environmental policy delivery. To guide the enquiry, this article organizes existing-partly contradictory-claims on the relation of scale, democratic legitimacy, and environmental effectiveness into three clusters of mechanisms, integrating insights from multi-level governance, social-ecological systems, and public participation. We empirically examine Water Framework Directive implementation in a comparative case study of multi-level systems in the light of the suggested mechanisms. We compare two planning areas in Germany: North Rhine Westphalia and Lower Saxony. Findings suggest that the Water Framework Directive did have some impact on institutionalizing hydrological scales and participation. Local participation appears generally both more effective and legitimate than on higher levels, pointing to the need for yet more tailored multi-level governance approaches, depending on whether environmental knowledge or advocacy is sought. We find mixed results regarding the potential of participation to bridge spatial 'misfits' between ecological and administrative scales of governance, depending on the historical institutionalization of governance on ecological scales. Polycentricity, finally, appeared somewhat favorable in effectiveness terms with some distinct differences regarding polycentricity in planning vs. polycentricity in implementation.

  11. Disentangling Puzzles of Spatial Scales and Participation in Environmental Governance—The Case of Governance Re-scaling Through the European Water Framework Directive

    Science.gov (United States)

    Newig, Jens; Schulz, Daniel; Jager, Nicolas W.

    2016-12-01

    This article attempts to shed new light on prevailing puzzles of spatial scales in multi-level, participatory governance as regards the democratic legitimacy and environmental effectiveness of governance systems. We focus on the governance re-scaling by the European Water Framework Directive, which introduced new governance scales (mandated river basin management) and demands consultation of citizens and encourages `active involvement' of stakeholders. This allows to examine whether and how re-scaling through deliberate governance interventions impacts on democratic legitimacy and effective environmental policy delivery. To guide the enquiry, this article organizes existing—partly contradictory—claims on the relation of scale, democratic legitimacy, and environmental effectiveness into three clusters of mechanisms, integrating insights from multi-level governance, social-ecological systems, and public participation. We empirically examine Water Framework Directive implementation in a comparative case study of multi-level systems in the light of the suggested mechanisms. We compare two planning areas in Germany: North Rhine Westphalia and Lower Saxony. Findings suggest that the Water Framework Directive did have some impact on institutionalizing hydrological scales and participation. Local participation appears generally both more effective and legitimate than on higher levels, pointing to the need for yet more tailored multi-level governance approaches, depending on whether environmental knowledge or advocacy is sought. We find mixed results regarding the potential of participation to bridge spatial `misfits' between ecological and administrative scales of governance, depending on the historical institutionalization of governance on ecological scales. Polycentricity, finally, appeared somewhat favorable in effectiveness terms with some distinct differences regarding polycentricity in planning vs. polycentricity in implementation.

  12. Reversible migration of silver on memorized pathways in Ag-Ge40S60 films

    Directory of Open Access Journals (Sweden)

    J. Orava

    2015-07-01

    Full Text Available Reversible and reproducible formation and dissolution of silver conductive filaments are studied in Ag-photodoped thin-film Ge40S60 subjected to electric fields. A tip-planar geometry is employed, where a conductive-atomic-force microscopy tip is the tip electrode and a silver patch is the planar electrode. We highlight an inherent “memory” effect in the amorphous chalcogenide solid-state electrolyte, in which particular silver-ion migration pathways are preserved “memorized” during writing and erasing cycles. The “memorized” pathways reflect structural changes in the photodoped chalcogenide film. Structural changes due to silver photodoping, and electrically-induced structural changes arising from silver migration, are elucidated using Raman spectroscopy. Conductive filament formation, dissolution, and electron (reduction efficiency in a lateral device geometry are related to operation of the nano-ionic Programmable Metallization Cell memory and to newly emerging chalcogenide-based lateral geometry MEMS technologies. The methods in this work can also be used for qualitative multi-parameter sampling of metal/amorphous-chalcogenide combinations, characterizing the growth/dissolution rates, retention and endurance of fractal conductive filaments, with the aim of optimizing devices.

  13. Reversible migration of silver on memorized pathways in Ag-Ge40S60 films

    Science.gov (United States)

    Orava, J.; Kozicki, M. N.; Yannopoulos, S. N.; Greer, A. L.

    2015-07-01

    Reversible and reproducible formation and dissolution of silver conductive filaments are studied in Ag-photodoped thin-film Ge40S60 subjected to electric fields. A tip-planar geometry is employed, where a conductive-atomic-force microscopy tip is the tip electrode and a silver patch is the planar electrode. We highlight an inherent "memory" effect in the amorphous chalcogenide solid-state electrolyte, in which particular silver-ion migration pathways are preserved "memorized" during writing and erasing cycles. The "memorized" pathways reflect structural changes in the photodoped chalcogenide film. Structural changes due to silver photodoping, and electrically-induced structural changes arising from silver migration, are elucidated using Raman spectroscopy. Conductive filament formation, dissolution, and electron (reduction) efficiency in a lateral device geometry are related to operation of the nano-ionic Programmable Metallization Cell memory and to newly emerging chalcogenide-based lateral geometry MEMS technologies. The methods in this work can also be used for qualitative multi-parameter sampling of metal/amorphous-chalcogenide combinations, characterizing the growth/dissolution rates, retention and endurance of fractal conductive filaments, with the aim of optimizing devices.

  14. Evidence for an unusual transmembrane configuration of AGG3, a Class C Gγ Subunit, of Arabidopsis

    OpenAIRE

    Wolfenstetter, Susanne; Chakravorty, David; Kula, Ryan; Urano, Daisuke; Trusov, Yuri; Sheahan, Michael B.; McCurdy, David W.; Assmann, Sarah M.; Alan M Jones; Jose R. Botella

    2014-01-01

    Heterotrimeric G proteins are crucial for the perception of external signals and subsequent signal transduction in animal and plant cells. In both model systems, the complex is comprised of one Gα, one Gβ and one Gγ subunit. However, in addition to the canonical Gγ subunits (Class A), plants also possess two unusual, plant-specific classes of Gγ subunits (Classes B and C) not yet found in animals. These include Gγ subunits lacking the C-terminal CaaX motif (Class B) which is important for mem...

  15. Translation of the FMR1 mRNA is not influenced by AGG interruptions

    OpenAIRE

    Ludwig, Anna L.; Raske, Christopher; Tassone, Flora; Garcia-Arocena, Dolores; Hershey, John W.; Hagerman, Paul J.

    2009-01-01

    The fragile X mental retardation 1 (FMR1) gene contains a CGG-repeat element within its 5′ untranslated region (5′UTR) which, for alleles with more than ∼40 repeats, increasingly affects both transcription (up-regulation) and translation (inhibition) of the repeat-containing RNA with increasing CGG-repeat length. Translational inhibition is thought to be due to impaired ribosomal scanning through the CGG-repeat region, which is postulated to form highly stable secondary/tertiary structure. On...

  16. Pharmacoresistant epilepsy: unmet needs in solving the puzzle(s).

    Science.gov (United States)

    Weaver, Donald F; Pohlmann-Eden, Bernd

    2013-05-01

    Pharmacoresistant epilepsy is a significant medical problem. The 2nd Halifax International Epilepsy Conference & Retreat identified crucial needs, which if successfully addressed, will aid in paving the way to improved lives for people with pharmacoresistant epilepsy. These are needs: (1) for an evidence-based and dynamic definition of pharmacoresistant epilepsy; (2) for a comprehensive description of the natural history of pharmacoresistant epilepsy; (3) for a comprehensive description of the complications and comorbidities of pharmacoresistant epilepsy; (4) for a rigorous delineation of the epidemiology and socioeconomic impact of pharmacoresistant epilepsy; (5) for clinically meaningful diagnostic and prognostic physiologically based electroencephalography (EEG) biomarkers; (6) for clinically meaningful diagnostic and prognostic anatomically based (MRI Imaging) biomarkers; (7) for biomolecular/biochemical mechanistic understanding of etiopathogenesis for pharmacoresistant epilepsy; (8) for representative animal models of pharmacoresistant epilepsy; (9) for new and effective drugs or other novel treatments for pharmacoresistant epilepsy; and (10) to promote continuing research and research funding targeting pharmacoresistant epilepsy.

  17. anti B{sub d,s} → D{sup *}{sub d,s}V and anti B{sup *}{sub d,s} → D{sub d,s}V decays in QCD factorization and possible puzzles

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Qin [Henan Normal University, Institute of Particle and Nuclear Physics, Henan (China); Central China Normal University, Institute of Particle Physics, Wuhan (China); Chen, Ling-Xin; Zhang, Yun-Yun; Sun, Jun-Feng; Yang, Yue-Ling [Henan Normal University, Institute of Particle and Nuclear Physics, Henan (China)

    2016-10-15

    Motivated by the rapid development of heavy-flavor experiments, phenomenological studies of nonleptonic anti B{sub d,s} → D{sup *}{sub d,s}V and anti B{sup *}{sub d,s} → D{sub d,s}V (V = ρ, K*) decays are performed within the framework of QCD factorization. Relative to the previous work, the QCD corrections to the transverse amplitudes are evaluated at next-to-leading order. The theoretical predictions of the observables are updated. For the measured anti B{sub d,s} → D{sup *}{sub d,s}V decays, the tensions between theoretical results and experimental measurements, i.e. the ''R{sub ds}{sup V} puzzle'' and ''D*V (or R{sub V/l} {sub anti} {sub ν{sub l)}} puzzle'', are presented after detailed analyses. For the anti B{sup *}{sub d,s} → D{sub d,s}V decays, they have relatively large branching fractions of the order >or similar O(10{sup -9}) and are in the scope of Belle-II and LHCb experiments. Moreover, they also provide a way to crosscheck the possible puzzles mentioned above through the similar ratios R{sub ds}{sup 'V} and R{sup '}{sub V/l} {sub anti} {sub ν{sub l.}} More refined experimental measurements and theoretical efforts are required to confirm or refute such two anomalies. (orig.)

  18. 中国股票市场非参与之谜分析%Analysis of the Non-Participation Puzzle of China's Stock Market

    Institute of Scientific and Technical Information of China (English)

    黄毓慧

    2014-01-01

    用微观调研数据分析中国股票市场非参与之谜,验证国外文献对该问题的解释:资金参与成本、认知水平,并进一步探索受教育程度、信息对认知水平的影响。实证分析从参与决策、参与深度两个层次递进展开,首先采用2SPLS克服认知水平和股市参与之间的内生性,证实了股市参与和认知之间存在双向因果关系,其次采用Tobit模型研究股票市场的参与深度。研究表明:中国股票市场参与受财富、教育、认知、信息等因素的影响,现阶段认知和信息的影响程度大于财富的影响程度,是影响中国股票市场参与的主要因素。结论凸显了投资者教育的重要性和紧迫性。%The paper analyzes the non-participation puzzle of China's stock market with mi-croscopic investigation data to prove the explanation in foreign literatures about the problem,such as capital participation cost and cognition level. Further studies are made on the education back-ground,and the influence of information on cognition level. Empirical study is made from two lev-els. Firstly,2SPLS is used to overcome the endogenous relationship between cognition level and stock market participation,which proves that there is a mutual cause-effect relationship between the two factors. Secondly,Tobit model is used to study the participation width of the stock market. Research shows that China's stock market is influenced by factors such as wealth,education,cog-nition and information. At present,the impacts of cognition and information are larger than that of the wealth,which are the main factors influencing China's stock market participation. Therefore, the education of investors becomes more important and urgent.

  19. Slow proton transfer coupled to unfolding explains the puzzling results of single-molecule experiments on BBL, a paradigmatic downhill folding protein.

    Directory of Open Access Journals (Sweden)

    Michele Cerminara

    Full Text Available A battery of thermodynamic, kinetic, and structural approaches has indicated that the small α-helical protein BBL folds-unfolds via the one-state downhill scenario. Yet, single-molecule fluorescence spectroscopy offers a more conflicting view. Single-molecule experiments at pH 6 show a unique half-unfolded conformational ensemble at mid denaturation, whereas other experiments performed at higher pH show a bimodal distribution, as expected for two-state folding. Here we use thermodynamic and laser T-jump kinetic experiments combined with theoretical modeling to investigate the pH dependence of BBL stability, folding kinetics and mechanism within the pH 6-11 range. We find that BBL unfolding is tightly coupled to the protonation of one of its residues with an apparent pKa of ~ 7. Therefore, in chemical denaturation experiments around neutral pH BBL unfolds gradually, and also converts in binary fashion to the protonated species. Moreover, under the single-molecule experimental conditions (denaturant midpoint and 279 K, we observe that proton transfer is much slower than the ~ 15 microseconds folding-unfolding kinetics of BBL. The relaxation kinetics is distinctly biphasic, and the overall relaxation time (i.e. 0.2-0.5 ms becomes controlled by the proton transfer step. We then show that a simple theoretical model of protein folding coupled to proton transfer explains quantitatively all these results as well as the two sets of single-molecule experiments, including their more puzzling features. Interestingly, this analysis suggests that BBL unfolds following a one-state downhill folding mechanism at all conditions. Accordingly, the source of the bimodal distributions observed during denaturation at pH 7-8 is the splitting of the unique conformational ensemble of BBL onto two slowly inter-converting protonation species. Both, the unprotonated and protonated species unfold gradually (one-state downhill, but they exhibit different degree of unfolding

  20. Chlorophyll d: the puzzle resolved

    DEFF Research Database (Denmark)

    Larkum, Anthony W D; Kühl, Michael

    2005-01-01

    Chlorophyll a (Chl a) has always been regarded as the sole chlorophyll with a role in photochemical conversion in oxygen-evolving phototrophs, whereas chlorophyll d (Chl d), discovered in small quantities in red algae in 1943, was often regarded as an artefact of isolation. Now, as a result...... of discoveries over the past year, it has become clear that Chl d is the major chlorophyll of a free-living and widely distributed cyanobacterium that lives in light environments depleted in visible light and enhanced in infrared radiation. Moreover, Chl d not only has a light-harvesting role but might also...... replace Chl a in the special pair of chlorophylls in both reactions centers of photosynthesis. Udgivelsesdato: 2005-Aug...

  1. The puzzle of monogamous marriage.

    Science.gov (United States)

    Henrich, Joseph; Boyd, Robert; Richerson, Peter J

    2012-03-01

    The anthropological record indicates that approximately 85 per cent of human societies have permitted men to have more than one wife (polygynous marriage), and both empirical and evolutionary considerations suggest that large absolute differences in wealth should favour more polygynous marriages. Yet, monogamous marriage has spread across Europe, and more recently across the globe, even as absolute wealth differences have expanded. Here, we develop and explore the hypothesis that the norms and institutions that compose the modern package of monogamous marriage have been favoured by cultural evolution because of their group-beneficial effects-promoting success in inter-group competition. In suppressing intrasexual competition and reducing the size of the pool of unmarried men, normative monogamy reduces crime rates, including rape, murder, assault, robbery and fraud, as well as decreasing personal abuses. By assuaging the competition for younger brides, normative monogamy decreases (i) the spousal age gap, (ii) fertility, and (iii) gender inequality. By shifting male efforts from seeking wives to paternal investment, normative monogamy increases savings, child investment and economic productivity. By increasing the relatedness within households, normative monogamy reduces intra-household conflict, leading to lower rates of child neglect, abuse, accidental death and homicide. These predictions are tested using converging lines of evidence from across the human sciences.

  2. The Cosmic Ray Lepton Puzzle

    CERN Document Server

    Brun, Pierre; Cirelli, Marco; Moulin, Emmanuel; Glicenstein, Jean-Francois; Iocco, Fabio; Pieri, Lidia

    2010-01-01

    Recent measurements of cosmic ray electrons and positrons by PAMELA, ATIC, Fermi and HESS have revealed interesting excesses and features in the GeV-TeV range. Many possible explanations have been suggested, invoking one or more nearby primary sources such as pulsars and supernova remnants, or dark matter. Based on the output of the TANGO in PARIS --Testing Astroparticle with the New GeV/TeV Observations in Positrons And electRons : Identifying the Sources-- workshop held in Paris in May 2009, we review here the latest experimental results and we discuss some virtues and drawbacks of the many theoretical interpretations proposed so far.

  3. Pieces to the Motivation Puzzle.

    Science.gov (United States)

    Powell, Lacey

    1984-01-01

    Students enter music classes for various reasons. Teachers must study the group in order to understand the attitudes and motivations of students. Advises the teacher to emphasize the intrinsic rewards of learning and to set individual strategies of positive reinforcement and negative punishment. (CS)

  4. America's Infant-Mortality Puzzle.

    Science.gov (United States)

    Eberstadt, Nicholas

    1991-01-01

    Conventional explanations attributing the high infant mortality rate in United States to the prevalence of poverty and lack of adequate health care do not tell the whole story. Contributions of parental behavior, lifestyles, and public health care availability versus utilization must be examined in determining public policies to address the…

  5. Geminga's puzzling pulsar wind nebula

    CERN Document Server

    Posselt, B; Slane, P O; Romani, R; Bucciantini, N; Bykov, A M; Kargaltsev, O; Weisskopf, M C; Ng, C -Y

    2016-01-01

    We report on six new Chandra observations of the Geminga pulsar wind nebula (PWN). The PWN consists of three distinct elongated structures - two $\\approx 0.2 d_{250}$ pc long lateral tails and a segmented axial tail of $\\approx 0.05 d_{250}$ pc length, where $d_{250}=d/(250 {\\rm pc})$. The photon indices of the power law spectra of the lateral tails, $\\Gamma \\approx 1$, are significantly harder than those of the pulsar ($\\Gamma \\approx 1.5$) and the axial tail ($\\Gamma \\approx 1.6$). There is no significant diffuse X-ray emission between the lateral tails -- the ratio of the X-ray surface brightness between the south tail and this sky area is at least 12. The lateral tails apparently connect directly to the pulsar and show indication of moving footpoints. The axial tail comprises time-variable emission blobs. However, there is no evidence for constant or decelerated outward motion of these blobs. Different physical models are consistent with the observed morphology and spectra of the Geminga PWN. In one scena...

  6. Phakellistatins: An Underwater Unsolved Puzzle

    Science.gov (United States)

    Meli, Alessandra; Tedesco, Consiglia; Della Sala, Giorgio; Schettini, Rosaria; Albericio, Fernando; De Riccardis, Francesco; Izzo, Irene

    2017-01-01

    A critical summary on the discovery of the nineteen members of the phakellistatin family (phakellistatin 1–19), cytotoxic proline-rich cyclopeptides of marine origin, is reported. Isolation, structural elucidation, and biological properties of the various-sized natural macrocycles are described, along with the total syntheses and the enigmatic issues of the cytotoxic activity reproducibility. PMID:28335479

  7. Horse trichinellosis, an unresolved puzzle

    Directory of Open Access Journals (Sweden)

    Pozio E.

    2001-06-01

    Full Text Available In spite of routine controls to detect Trichinella larvae in horse-meat, human infections due to horse-meat consumption continue to occur in France and Italy, The epidemiology of horse trichinellosis since its discovery in 1975 is outlined, addressing the possible modes of natural transmission to horses, the need to develop more sensitive methods for detecting Trichinella larvae in horses, and the economic impact of horse trichinellosis. Investigations of human outbreaks due to horse-meat consumption have implicated single cases of inadequate veterinary controls on horses imported from non-European Union countries. In particular, most cases of human infection have been attributed to horses imported from Eastern Europe, where pig trichinellosis is re-emerging and the main source of infection in horses.

  8. The puzzling MILAGRO hot spots

    CERN Document Server

    Drury, Luke

    2008-01-01

    We discuss the reported detection by the MILAGRO experiment of localised hot spots in the cosmic ray arrival distribution and the difficulty of interpreting these observations. A model based on secondary neutron production in the heliotail is shown to fail. An alternative model based on loss-cone leakage through a magnetic trap from a local source region is proposed.

  9. The Middle East population puzzle.

    Science.gov (United States)

    Omran, A R; Roudi, F

    1993-07-01

    An overview is provided of Middle Eastern countries on the following topics; population change, epidemiological transition theory and 4 patterns of transition in the middle East, transition in causes of death, infant mortality declines, war mortality, fertility, family planning, age and sex composition, ethnicity, educational status, urbanization, labor force, international labor migration, refugees, Jewish immigration, families, marriage patterns, and future growth. The Middle East is geographically defined as Bahrain, Egypt, Iraq, Jordan, Kuwait, Lebanon, Oman, Qatar, Saudi Arabia, Syria, United Arab Emirates, Yemen, Gaza and the West Bank, Iran, Turkey, and Israel. The Middle East's population grew very little until 1990 when the population was 43 million. Population was about doubled in the mid-1950s at 80 million. Rapid growth occurred after 1950 with declines in mortality due to widespread disease control and sanitation efforts. Countries are grouped in the following ways: persistent high fertility and declining mortality with low to medium socioeconomic conditions (Jordan, Oman, Syria, Yemen, and the West Bank and Gaza), declining fertility and mortality in intermediate socioeconomic development (Egypt, Lebanon, Turkey, and Iran), high fertility and declining mortality in high socioeconomic conditions (Bahrain, Iraq, Kuwait, Qatar, Saudi Arabia, and the United Arab Emirates), and low fertility and mortality in average socioeconomic conditions (Israel). As birth and death rates decline, there is an accompanying shift from communicable diseases to degenerative diseases and increases in life expectancy; this pattern is reflected in the available data from Egypt, Kuwait, and Israel. High infant and child mortality tends to remain a problem throughout the Middle East, with the exception of Israel and the Gulf States. War casualties are undetermined, yet have not impeded the fastest growing population growth rate in the world. The average fertility is 5 births/woman by the age of 45. Muslim countries tend to have larger families. Contraceptive use is low in the region, with the exception of Turkey and Egypt and among urban and educated populations. More than 40% of the population is under 15 years of age. The region is about 50% Arabic (140 million). Educational status has increased, particularly for men; the lowest literacy rates for women are in Yemen and Egypt. The largest countries are Iran, Turkey, and Egypt.

  10. Heisenberg Honeycombs Solve Veneziano Puzzle

    CERN Document Server

    Kholodenko, A L

    2006-01-01

    In this paper we reformulate some results obtained by Heisenberg into modern mathematical language of honeycombs. This language was developed in connection with complete solution of the Horn conjecture problem. Such a reformulation is done with the purpose of posing and solving the following problem. Is by analysing the (spectroscopic) experimental data it possible to restore the underlying microscopic physical model generating these data? Development of Heisenberg's ideas happens to be the most useful for this purpose. Solution is facilitated by our earlier developed string-theoretic formalism. In this paper only qualitative arguments are presented (with few exceptions). These arguments provide enough evidence that the underelying microscopic model compatible with Veneziano-type amplitudes is the standard (i.e. non supersymmetric!) QCD. In addition, usefulness of the formalism is illustrated on numerous examples such as physically motivated solution of the saturation conjecture, derivation of the Yang-Baxter...

  11. The Exchange Rate Forecasting Puzzle

    OpenAIRE

    Francis Vitek

    2005-01-01

    We survey and update the empirical literature concerning the predictability of nominal exchange rates using structural macroeconomic models over the recent floating exchange rate period. In particular, we consider both flexible and sticky price versions of the monetary model of nominal exchange rate determination. In agreement with the existing empirical literature, we find that nominal exchange rate movements are difficult to forecast, with a random walk generally dominating the monetary mod...

  12. Reviewing the Puzzle of CLIL

    Science.gov (United States)

    Ioannou Georgiou, Sophie

    2012-01-01

    Content and language integrated learning (CLIL) has become a well-known term for foreign language teachers and language researchers. A little more than a decade ago, it was a term unheard of in most staff rooms or professional conferences. This paper seeks to define CLIL and to look into the reasons that have propelled it to widespread adoption.…

  13. Reviews Equipment: BioLite Camp Stove Game: Burnout Paradise Equipment: 850 Universal interface and Capstone software Equipment: xllogger Book: Science Magic Tricks and Puzzles Equipment: Spinthariscope Equipment: DC Power Supply HY5002 Web Watch

    Science.gov (United States)

    2013-05-01

    WE RECOMMEND BioLite CampStove Robust and multifaceted stove illuminates physics concepts 850 Universal interface and Capstone software Powerful data-acquisition system offers many options for student experiments and demonstrations xllogger Obtaining results is far from an uphill struggle with this easy-to-use datalogger Science Magic Tricks and Puzzles Small but perfectly formed and inexpensive book packed with 'magic-of-science' demonstrations Spinthariscope Kit for older students to have the memorable experience of 'seeing' radioactivity WORTH A LOOK DC Power Supply HY5002 Solid and effective, but noisy and lacks portability HANDLE WITH CARE Burnout Paradise Car computer game may be quick off the mark, but goes nowhere fast when it comes to lab use WEB WATCH 'Live' tube map and free apps would be a useful addition to school physics, but maths-questions website of no more use than a textbook

  14. FIAs (Foliation Intersection/Inflection Axes) Preserved in Porphyroblasts,the DNA of Deformation: A Solution to the Puzzle of Deformation and Metamorphism in the Colorado, Rocky Mountains, USA

    Institute of Scientific and Technical Information of China (English)

    SHAH Afroz Ahmad

    2009-01-01

    FIAs have been used extensively for more than a decade to unravel deformation and metamorphic puzzles. Orogenic processes developing early during the history or orogenesis challenge scientists because compositional layering in rocks always reactivates where multiple deformations have occurred, leaving little evidence of the history of foliation development preserved in the matrix. The foothills of the Rocky Mountains in Colorado, USA contain a succession of four FIA sets (trends) that would not have been distinguishable if porphyroblasts had not grown during the multiple deformation events that affected these rocks or if they had rotated as these events took place. They reveal that both the partitioning of deformation and the location of isograds changed significantly as the deformation proceeded.

  15. $\\bar{B}_{d,s} \\to D^{*}_{d,s} V$ and $\\bar{B}_{d,s}^* \\to D_{d,s} V$ decays with QCD Factorization and Possible Puzzles

    CERN Document Server

    Chang, Qin; Zhang, Yun-Yun; Sun, Jun-Feng; Yang, Yue-Ling

    2016-01-01

    Motivated by the rapid development of heavy-flavor experiments, phenomenological studies of nonleptonic $\\bar{B}_{d,s} \\to D^{*}_{d,s} V$ and $\\bar{B}_{d,s}^* \\to D_{d,s} V$~($V=\\rho\\,,K^*$) decays are performed within the framework of QCD Factorization. Relative to previous works, the QCD corrections to the transverse amplitudes are evaluated at next-to-leading order. The theoretical predictions of the observables are updated. For the measured $\\bar{B}_{d,s} \\to D^{*}_{d,s} V$ decays, two tensions between theoretical results and experimental measurements, {\\it i.e.} "$R_{ds}^{V}$ puzzle" and "$D^{*} V$~(or $R_{V/\\ell\\bar{\

  16. Insulin/receptor binding: the last piece of the puzzle? What recent progress on the structure of the insulin/receptor complex tells us (or not) about negative cooperativity and activation.

    Science.gov (United States)

    De Meyts, Pierre

    2015-04-01

    Progress in solving the structure of insulin bound to its receptor has been slow and stepwise, but a milestone has now been reached with a refined structure of a complex of insulin with a "microreceptor" that contains the primary binding site. The insulin receptor is a dimeric allosteric enzyme that belongs to the family of receptor tyrosine kinases. The insulin binding process is complex and exhibits negative cooperativity. Biochemical evidence suggested that insulin, through two distinct binding sites, crosslinks two receptor sites located on each α subunit. The structure of the unliganded receptor ectodomain showed a symmetrical folded-over conformation with an antiparallel disposition. Further work resolved the detailed structure of receptor site 1, both without and with insulin. Recently, a missing piece in the puzzle was added: the C-terminal portion of insulin's B-chain known to be critical for binding and negative cooperativity. Here I discuss these findings and their implications.

  17. 3-loop Massive $O(T_F^2)$ Contributions to the DIS Operator Matrix Element $A_{gg}$

    CERN Document Server

    Ablinger, J; De Freitas, A; Hasselhuhn, A; von Manteuffel, A; Round, M; Schneider, C

    2014-01-01

    Contributions to heavy flavour transition matrix elements in the variable flavour number scheme are considered at 3-loop order. In particular a calculation of the diagrams with two equal masses that contribute to the massive operator matrix element $A_{gg,Q}^{(3)}$ is performed. In the Mellin space result one finds finite nested binomial sums. In $x$-space these sums correspond to iterated integrals over an alphabet containing also square-root valued letters.

  18. Stock Market Volatility Puzzle ,and Market Sentiment in Chinese A-share Stock Markets%我国A股市场中的波动性之谜与市场情绪

    Institute of Scientific and Technical Information of China (English)

    周洪荣; 吴卫星; 周业安

    2012-01-01

    本文使用Campbell和Shiller(1988)基于对数线性RVF的VAR非线性Wald检验方法对我国A股1994—2009期间的数据进行实证研究,结果表明样本期间我国A股股价相对其基础价值表现出“过度波动”的迹象,无论是常数超额收益率模型还是V-CAPM模型都无法对此进行解释。通过进一步定义市场情绪指数来分析这种“波动性之谜”现象的原因,结果发现市场情绪和股市“过度波动”之间存在相互作用机制,市场情绪能够对股价波动提供额外的解释。%In this paper, we analyze whether the Chinese A share stock markets exhibit excess volatility by employing the VAR methodology based on log-linear RVF of Campbell&Shiller (1988). According to our result, relative to the intrinsic value implied by dividends, Chinese A share stock markets always exhibit excessive volatility for the period of 1994 to 2009. It is difficult to explain the stock market volatility puzzle of China's stock market, no matter we run constant excess return model or V-CAPM model. We try to explain the reasons by studying the stock market sentiment index, and find evidence of an interaction mechanism between investor sentiment and excess volatility. And one more meaningful result is that adding the stock market sentiment index to our model can provide extra explanatory power for the excess volatility of the stock market.

  19. Investor sentiment, disagreement and IPO puzzle in China’ s stock market%投资者情绪、意见分歧与中国股市IPO之谜

    Institute of Scientific and Technical Information of China (English)

    俞红海; 李心丹; 耿子扬

    2015-01-01

    中国股票市场IPO首日回报高、长期回报低的现象十分突出,传统理性金融理论难以对这两者同时加以解释。文章基于行为金融理论,从二级市场个体投资者情绪与意见分歧相结合的角度,利用账户交易数据中的投资者IPO首日净买入构建情绪指标对上述现象进行研究,结果表明IPO首日投资者情绪和意见分歧均对IPO首日回报有显著为正的解释力,尤其是当意见分歧严重时,投资者情绪的影响更大,同时首日投资者情绪对IPO长期超额回报有显著为负的影响,但意见分歧却对长期回报没有影响。文章的研究从二级市场个体投资者非理性偏好角度揭示了中国股市“IPO之谜”产生的根源。%The phenomena of high initial IPO returns and poor long-term returns are popular in China ’ s stock market , and the traditional rational financial theory is unable to explain such phenomena at the same time .In this paper , based on the behavioral financial theory , from the perspective of investor sentiment and disagree-ment, we construct a buy-sell imbalance(BSI) index, using initial IPO from the investors’ trading data, to represent investor sentiment to study these IPO phenomena in China .We find that investors ’ sentiment and disagreement both have significant positive impacts on the initial returns , and when the disagreement is big , the impact of sentiment is more serious .Meanwhile , sentiment has significant positive impact on the long-term abnormal return, but disagreement has no such impact .This paper provides explanations to the IPO puzzle in China ’ s stock market from the perspective of individual investors ’ irrational biases .

  20. Solving the RNA polymerase I structural puzzle

    Energy Technology Data Exchange (ETDEWEB)

    Moreno-Morcillo, María [European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg (Germany); Taylor, Nicholas M. I. [Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040 Madrid (Spain); Gruene, Tim [Georg-August-University, Tammannstrasse 4, 37077 Göttingen (Germany); Legrand, Pierre [SOLEIL Synchrotron, L’Orme de Merisiers, Saint Aubin, Gif-sur-Yvette (France); Rashid, Umar J. [European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg (Germany); Ruiz, Federico M. [Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040 Madrid (Spain); Steuerwald, Ulrich; Müller, Christoph W. [European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg (Germany); Fernández-Tornero, Carlos, E-mail: cftornero@cib.csic.es [Consejo Superior de Investigaciones Científicas, Ramiro de Maeztu 9, 28040 Madrid (Spain); European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg (Germany)

    2014-10-01

    Details of the RNA polymerase I crystal structure determination provide a framework for solution of the structures of other multi-subunit complexes. Simple crystallographic experiments are described to extract relevant biological information such as the location of the enzyme active site. Knowing the structure of multi-subunit complexes is critical to understand basic cellular functions. However, when crystals of these complexes can be obtained they rarely diffract beyond 3 Å resolution, which complicates X-ray structure determination and refinement. The crystal structure of RNA polymerase I, an essential cellular machine that synthesizes the precursor of ribosomal RNA in the nucleolus of eukaryotic cells, has recently been solved. Here, the crucial steps that were undertaken to build the atomic model of this multi-subunit enzyme are reported, emphasizing how simple crystallographic experiments can be used to extract relevant biological information. In particular, this report discusses the combination of poor molecular replacement and experimental phases, the application of multi-crystal averaging and the use of anomalous scatterers as sequence markers to guide tracing and to locate the active site. The methods outlined here will likely serve as a reference for future structural determination of large complexes at low resolution.

  1. Intraosseous disc prolapse: A diagnostic puzzle

    Directory of Open Access Journals (Sweden)

    Parasnis Rajesh

    2006-01-01

    Full Text Available Background : Schmorl′s node or intraosseous disc prolapse is herniation of the nucleus pulposus material through the vertebral end plates. Presence of Schmorl′s nodes as end plate lesions following trauma, tumours and osteoporosis further complicates diagnosis. The present study was done to understand diagnosis and approach to management of symptomatic Schmorl′s nodes. Methods : During a period of three years we came across 14 patients who presented with severe back pain. Conventional radiographs, CT Scans and MRI showed the presence of end plate lesions with varied radiological appearance. The first group, comprising of seven patients had lytic lesions without any sclerosis on only one side of the intervertebral disc as seen on the CT scan. The second group comprising of five patients had sclerotic lesions with new bone formation associated with disc space reduction. The two patients in the third group showed a combined lytic and sclerotic lesion without any soft tissue changes. MRI of eleven patients revealed hypointense lesion on T 1 and T 2 weighted images with surrounding zone of hyper intensity on T 2 weighted images. The remaining three patients, did not have this hyper intense zone on T 2 weighted images . In five patients multiple Schmorl′s nodes were observed. Diagnosis of symptomatic Schmorl′s nodes was mainly done by exclusion. All patients were given rest and anti-inflammatory drugs followed by exercises. Results : The first two groups of patients responded to the treatment and had complete relief of symptoms but both the patients in third group had persistent symptoms. MRI repeated after eight weeks showed an enhancing lesion with prevertebral soft tissue. A transpedicular core biopsy proved the lesion to be tuberculosis in one patient. Anti Koch′s therapy was promptly started and follow up study showed resolution of the lesions. At the end of the study period all the patients were asymptomatic and returned to their active profession. Conclusion : The difficulty in diagnosis is attributed to the fact that every person with Schmorl′s node is not symptomatic. For accurate diagnosis it is necessary to have high index of suspicion, close follow up and exclusion of other associated conditions. In case of poor response to conservative treatment an alternative diagnosis has to be considered and if required it should be proved or disproved by a biopsy of the lesion (percutaneous or open.

  2. THE PUZZLE OF SIMULTANEOUS SAVINGS AND DEBTS

    Directory of Open Access Journals (Sweden)

    RODICA IANOLE

    2012-05-01

    Full Text Available „Neither a borrower nor a lender be” recommends Shakespeare in Hamlet. The advice seems particularly interesting in nowadays society where a person can be easily found in both approximate situations, in the same time. It goes without saying that saving and borrowing do not describe mutually exclusive strategies of financial management and thus many people retain savings or carry on saving at the same time as having debts. We add to this fact a more pragmatically wisdom, the one of the economist Robert Solow -“We (economists think of wealth as fungible; we think a dollar is a dollar. Why don't they (the others do so?” (Solow, 1987 – and we naturally ask ourselves if the mechanism of having simultaneous savings and debts is a rational one, according to traditional economics.Making appeal to the emerging body of behavioral economics literature we reach to the mental accounting theory to see if it can explain savings inclination versus debt inclination. The main research question we want to explore is the following: if mental accounting prevents people from spending money from one „mental account” on goods belonging to another one, will people – after using all their money from a given account – be willing to go into debt to buy goods belonging to this account in a situation when they still have money in other accounts?

  3. Confronting the Puzzle of Nonverbal Learning Disabilities.

    Science.gov (United States)

    Vacca, Dorothy M.

    2001-01-01

    Describes characteristics of students with nonverbal learning disorders and offers teachers suggestions for helping them work with students with these disabilities. Includes story of one nonverbal learning-disabled student's school experience. (PKP)

  4. The puzzles of dark matter searches

    Science.gov (United States)

    Khlopov, Maxim Yu.

    2010-06-01

    Positive results of dark matter searches in DAMA/NaI and DAMA/LIBRA experiments, being put together with negative results of other groups, imply nontrivial particle physics solutions for cosmological dark matter. Stable particles with charge -2 bind with primordial helium in O-helium ``atoms'' (OHe), representing a specific Warmer than Cold nuclear-interacting form of dark matter. Slowed down in the terrestrial matter, OHe is elusive for direct methods of underground Dark matter detection like those used in CDMS experiment, but its reactions with nuclei can lead to annual variations of energy release in the interval of energy 2-6 keV in DAMA/NaI and DAMA/LIBRA experiments. Schrodinger equation for system of nucleus and OHe is considered and reduced to an equation of relative motion in a spherically symmetrical potential well, formed by the Yukawa tail of nuclear scalar isoscalar attraction potential, acting on He beyond the nucleus, and dipole Coulomb repulsion between the nucleus and OHe at distances from the nuclear surface, smaller than the size of OHe. The values of coupling strength and mass of meson, mediating scalar isoscalar nuclear potential, are rather uncertain. Within these uncertainties we find a narrow window of these parameters, at which the sodium and/or iodine nuclei have a few keV binding energy with OHe. The concentration of OHe in the matter of underground detectors is adjusted to the incoming flux of cosmic O-helium at the timescale less than few minutes. Therefore the rate of radiative capture of Na and/or I by OHe should experience annual modulations. Transitions to more energetic levels of Na+OHe (I+OHe) system imply tunneling through dipole Coulomb barrier that leads to suppression of annual modulation of events with MeV-tens MeV energy release in the correspondence with the results of DAMA experiments. The proposed explanation inevitably leads to prediction of abundance of anomalous Na (and/or I) corresponding to the signal, observed by DAMA. At nuclear parameters, reproducing DAMA results, the energy release predicted for detectors with chemical content other than NaI differ in the most cases from the one in DAMA detector. In particular, it is shown that in the case of CDMS the energy of OHe-germanium bound state is beyond the range of 2-6 keV and its formation should not lead to ionization in the energy interval of DAMA signal.

  5. The Chinese Puzzle of Low Profit Tea

    Institute of Scientific and Technical Information of China (English)

    LUOYUANJUN

    2004-01-01

    There are too many tea varieties, factories, and styles of packaging and too few registered trademarks and known domestic and international brands. No brand name means no market, let alone reputation or consumer loyalty. Beneath the superficially prosperous Chinese tea industry there lurks a nagging insecurity over its dearth of brand names.

  6. Solving the Plagiary Puzzle with Role Plays.

    Science.gov (United States)

    Moder, Carol Lynn; Halleck, Gene B.

    1995-01-01

    Presents exercises and role plays designed to help English-as-a-Second-Language (ESL) students enrolled in or bound for American universities understand plagiarism and the need to properly document essays and term papers. (five references) (MDM)

  7. The electron screening puzzle and nuclear clustering

    Directory of Open Access Journals (Sweden)

    C. Spitaleri

    2016-04-01

    Full Text Available Accurate measurements of nuclear reactions of astrophysical interest within, or close to, the Gamow peak show evidence of an unexpected effect attributed to the presence of atomic electrons in the target. The experiments need to include an effective “screening” potential to explain the enhancement of the cross sections at the lowest measurable energies. Despite various theoretical studies conducted over the past 20 years and numerous experimental measurements, a theory has not yet been found that can explain the cause of the exceedingly high values of the screening potential needed to explain the data. In this letter we show that instead of an atomic physics solution of the “electron screening puzzle”, the reason for the large screening potential values is in fact due to clusterization effects in nuclear reactions, in particular for reaction involving light nuclei.

  8. Social Disadvantage and Crime: A Criminological Puzzle.

    Science.gov (United States)

    Wikström, Per-Olof H; Treiber, Kyle

    2016-09-01

    In this article, we analyze the relationship between social disadvantage and crime, starting from the paradox that most persistent offenders come from disadvantaged backgrounds, but most people from disadvantaged backgrounds do not become persistent offenders. We argue that despite the fact that social disadvantage has been a key criminological topic for some time, the mechanisms which link it to offending remain poorly specified. Drawing on situational action theory, we suggest social disadvantage is linked to crime because more people from disadvantaged versus affluent backgrounds develop a high crime propensity and are exposed to criminogenic contexts, and the reason for this is that processes of social and self-selection place the former more frequently in (developmental and action) contexts conducive to the development and expression of high crime propensities. This article will explore this hypothesis through a series of analyses using data from the Peterborough Adolescent and Young Adult Development Study (PADS+), a longitudinal study which uses a range of data collection methods to study the interaction between personal characteristics and social environments. It pays particular attention to the macro-to-micro processes behind the intersection of people with certain characteristics and environments with certain features - i.e., their exposure - which leads to their interaction.

  9. Rare Disasters and Credit Market Puzzles

    DEFF Research Database (Denmark)

    Christoffersen, Peter; Du, Du; Elkamhi, Redouane

    to the real economy and not to bond prices can simultaneously explain several key empirical regularities in credit markets. Our model captures the empirical level and volatility of credit spreads, generates a flexible credit risk term structure, and provides a good fit to a century of observed spreads...

  10. The Eco-Efficiency Premium Puzzle

    NARCIS (Netherlands)

    J. Derwall (Jeroen); N.K. Günster (Nadja); R. Bauer (Rob); C.G. Koedijk (Kees)

    2004-01-01

    textabstractThere exists a widespread consensus among mainstream academics and investors that socially responsible investing (SRI) leads to inferior, rather than superior, portfolio performance. Using Innovest’s well-established corporate ecoefficiency scores, we provide evidence to the contrary. We

  11. Assembling puzzles / Emil Urbel ; intervjueerinud Ingrid Ruudi

    Index Scriptorium Estoniae

    Urbel, Emil, 1959-

    2010-01-01

    Arhitekt Emil Urbeli projekteeritud minimalistlikest eramutest Nõmmel ja Miidurannas, Aaviku elamurajoonist, Esku tänava ridaelamutest Tallinnas, SEB pangahoonest Tartus. Elukeskkonnale esitatavate nõudmiste muutumisest viimastel aastakümnetel. Arhitekti tööprotsessist, koostööst arendajate ja ehitajatega

  12. The Dutch local government bailout puzzle

    NARCIS (Netherlands)

    Allers, Maarten

    2015-01-01

    The fiscal federalism and public choice literatures stress that government bailouts should be ruled out as they increase the probability that jurisdictions will incur unsustainable debt levels or take excessive risk (moral hazard problem). The recent problems in the euro area seem to confirm this vi

  13. Drinking in snakes: resolving a biomechanical puzzle.

    Science.gov (United States)

    Cundall, David; Brainerd, Elizabeth L; Constantino, Joseph; Deufel, Alexandra; Grapski, Douglas; Kley, Nathan J

    2012-03-01

    Snakes have long been thought to drink with a two-phase buccal-pump mechanism, but observations that some snakes can drink without sealing the margins of their mouths suggest that buccal pumping may not be the only drinking mechanism used by snakes. Here, we report that some snakes appear to drink using sponge-like qualities of specific regions of the oropharyngeal and esophageal mucosa and sponge-compressing functions of certain muscles and bones of the head. The resulting mechanism allows them to transport water upward against the effects of gravity using movements much slower than those of many other vertebrates. To arrive at this model, drinking was examined in three snake species using synchronized ciné and electromyographic recordings of muscle activity and in a fourth species using synchronized video and pressure recordings. Functional data were correlated with a variety of anatomical features to test specific predictions of the buccal-pump model. The anatomical data suggest explanations for the lack of conformity between a buccal-pump model of drinking and the performance of the drinking apparatus in many species. Electromyographic data show that many muscles with major functions in feeding play minor roles in drinking and, conversely, some muscles with minor roles in feeding play major roles in drinking. Mouth sealing by either the tongue or mental scale, previously considered critical to drinking in snakes, is incidental to drinking performance in some species. The sponge mechanism of drinking may represent a macrostomatan exaptation of mucosal folds, the evolution of which was driven primarily by the demands of feeding.

  14. Quarks and leptons: the generation puzzle

    Energy Technology Data Exchange (ETDEWEB)

    Harari, H.

    1979-07-01

    Some crucial questions with regards to the physics of the world beyond the standard view of quarks and leptons are investigated. The standard view is set forth, its problems noted, and its possibilities considered, particularly that of the grand unification scheme. Some open questions are listed. 29 references. (JFP)

  15. ICT Productivity in Japan: Another Puzzle?

    OpenAIRE

    Shinozaki, Akihiko

    2004-01-01

    This study is intended to examine whether information and communications technology (ICT) has contributed to aggregate productivity growth in Japan over the last two decades. Growth accounting analysis yields two observations. First, investment in ICT accelerated in Japan in the 1980s and slowed down in the 1990s. Second, the periodical changes of multifactor productivity growth and the contribution of ICT capital assets have always run in a parallel direction since the 1980s. Therefore, the ...

  16. The Puzzling Spectrum of HD 94509

    CERN Document Server

    Cowley, C R; Hubrig, S

    2015-01-01

    The spectral features of HD 94509 are highly unusual, adding an extreme to the zoo of Be and shell stars. The shell dominates the spectrum, showing lines typical for spectral types mid-A to early-F, while the presence of a late/mid B-type central star is indicated by photospheric hydrogen line wings and helium lines. Numerous metallic absorption lines have broad wings but taper to narrow cores. They cannot be fit by Voigt profiles. We aim to describe and illustrate unusual spectral features of this star, and make rough calculations to estimate physical conditions and abundances in the shell. Furthermore, the central star is characterized. We assume mean conditions for the shell. An electron density estimate is made from the Inglis-Teller formula. Excitation temperatures and column densities for Fe I and Fe II are derived from curves of growth. The neutral H column density is estimated from high Paschen members. The column densities are compared with calculations made with the photoionization code Cloudy. Atmo...

  17. Management of Strongyloides stercoralis: a puzzling parasite.

    Science.gov (United States)

    Luvira, Viravarn; Watthanakulpanich, Dorn; Pittisuttithum, Punnee

    2014-12-01

    Strongyloides stercoralis is one of the common parasites in tropical areas. It can result in severe clinical syndromes, hyperinfection syndrome or disseminated strongyloidiasis in immunocompromised patients. The treatment of strongyloidiasis is a challenge for clinicians in clinical practice. Failure of treatment is due to autoinfection caused by the parasite life cycle and impairment of host immunity. Ivermectin currently is the treatment of choice. When compared with thiabendazole, it has shown a similar efficacy with better tolerability. However, there is neither consensus in duration of treatment nor in repetition of doses. The keys for management of this tough parasite include proper evaluation and prevention. Stool examination with high sensitivity techniques such as Baermann technique, filter-paper culture and agar-plate culture and specific IgG serology should be used in evaluation for 1 to 2 years. Screening, both stool examination and serology, before patients have immunosuppressive treatment is needed to prevent the severe form of strongyloidiasis.

  18. Geminga’s Puzzling Pulsar Wind Nebula

    Science.gov (United States)

    Posselt, B.; Pavlov, G. G.; Slane, P. O.; Romani, R.; Bucciantini, N.; Bykov, A. M.; Kargaltsev, O.; Weisskopf, M. C.; Ng, C.-Y.

    2017-01-01

    We report on six new Chandra observations of the Geminga pulsar wind nebula (PWN). The PWN consists of three distinct elongated structures—two ≈ 0.2{d}250 pc long lateral tails and a segmented axial tail of ≈ 0.05{d}250 pc length, where {d}250=d/(250 {pc}). The photon indices of the power-law spectra of the lateral tails, {{Γ }}≈ 1, are significantly harder than those of the pulsar ({{Γ }}≈ 1.5) and the axial tail ({{Γ }}≈ 1.6). There is no significant diffuse X-ray emission between the lateral tails—the ratio of the X-ray surface brightness between the south tail and this sky area is at least 12. The lateral tails apparently connect directly to the pulsar and show indications of moving footpoints. The axial tail comprises time-variable emission blobs. However, there is no evidence for constant or decelerated outward motion of these blobs. Different physical models are consistent with the observed morphology and spectra of the Geminga PWN. In one scenario, the lateral tails could represent an azimuthally asymmetric shell whose hard emission is caused by the Fermi acceleration mechanism of colliding winds. In another scenario, the lateral tails could be luminous, bent polar outflows, while the blobs in the axial tail could represent a crushed torus. In a resemblance to planetary magnetotails, the blobs of the axial tail might also represent short-lived plasmoids, which are formed by magnetic field reconnection in the relativistic plasma of the pulsar wind tail.

  19. Proton radius puzzle in Hamiltonian dynamics

    CERN Document Server

    Glazek, Stanislaw D

    2014-01-01

    Relativistic lepton-proton bound-state eigenvalue equations for Hamiltonians derived from quantum field theory using second-order renormalization group procedure for effective particles, are reducible to two-body Schroedinger eigenvalue equations with the effective Coulomb potential that exhibits a tiny sensitivity to the characteristic momentum-scale of the bound system. The scale dependence is shown to be relevant to the theoretical interpretation of precisely measured lepton-proton bound-state energy levels in terms of a 4 percent difference between the proton radii in muon-proton and electron-proton bound states.

  20. Puzzling Phenomenon of Diffuse Interstellar Bands

    CERN Document Server

    Wszolek, B

    2007-01-01

    The discovery of the first diffuse interstellar bands (DIBs) dates back to the pioneering years of stellar spectroscopy. Today, we know about 300 absorption structures of this kind. There exists a great variety of the profiles and intensities of DIBs, so they can not be readily described, classified or characterized. To the present day no reliable identification of the DIBs' carriers has been found. Many carriers of DIBs have been proposed over the years. They ranged from dust grains to free molecules of different kinds, and to more exotic specimens, like hydrogen negative ion. Unfortunately, none of them is responsible for observed DIBs. Furthermore, it was shown that a single carrier cannot be responsible for all known DIBs. It is hard to estimate how many carriers can participate in producing these bands. The problem is further complicated by the fact that to this day it is still impossible to find any laboratory spectrum of any substance which would match the astrophysical spectra. Here, a historical outl...

  1. The Puzzle of V407 Cygni

    Directory of Open Access Journals (Sweden)

    R. Hudec

    2011-01-01

    Full Text Available We discuss the nature and recent observations (optical and gamma-rays of symbiotics binary/Mira variable V407 Cygni. In addition we discuss another object of similar category, namely the variable star FY Aql with possible association with an eruptive gamma-ray source.

  2. Moving pieces in a venomic puzzle

    DEFF Research Database (Denmark)

    Verano-Braga, Thiago; Dutra, Alexandre A A; León, Ileana R

    2013-01-01

    Besides being a public health problem, scorpion venoms have a potential biotechnological application since they contain peptides that may be used as drug leads and/or to reveal novel pharmacological targets. A comprehensive Tityus serrulatus venom proteome study with emphasis on the phosphoproteome...

  3. Macroeconomic Perspectives on the Equity Premium Puzzle

    NARCIS (Netherlands)

    J. Zenhorst (Jorn)

    2012-01-01

    textabstractSuppose you were born on January 1, 1983. A few months later, your parents, wanting to set aside some money for your 18th birthday, were at a crossroads. They could either invest money in risk-free Dutch government bonds or in the newly created AEX index, investing in companies’ shares.

  4. The CO/Pt(111) Puzzle

    Energy Technology Data Exchange (ETDEWEB)

    FEIBELMAN,PETER J.; HAMMER,B.; NORSHOV,J.K.; WAGNER,F.; SCHEFFLER,M.; STUMPF,R.; DUMESIC,J.; WATWE,R.

    2000-07-12

    Notwithstanding half a dozen theoretical publications, well-converged density-functional calculations, whether based on a local or generalized-gradient exchange-correlation potential, whether all-electron or employing pseudopotentials underestimate CO's preference for low-coordination binding sites on Pt(111) and vicinals to it. For example, they imply that CO should prefer hollow- to atop-site adsorption on Pt(111), in apparent contradiction to a host of low temperature experimental studies.

  5. THE SCHULHOF FAMILY: SOLVING THE AGE PUZZLE

    Energy Technology Data Exchange (ETDEWEB)

    Vokrouhlický, David; Ďurech, Josef [Institute of Astronomy, Charles University, V Holešovičkách 2, CZ-18000 Prague 8 (Czech Republic); Pravec, Petr; Kušnirák, Peter; Hornoch, Kamil; Vraštil, Jan [Astronomical Institute, Czech Academy of Sciences, Fričova 298, CZ-251 65 Ondrejov (Czech Republic); Krugly, Yurij N. [Institute of Astronomy of Kharkiv National University, Sumska Str. 35, 61022 Kharkiv (Ukraine); Inasaridze, Raguli Ya.; Ayvasian, Vova; Zhuzhunadze, Vasili [Kharadze Abastumani Astrophysical Observatory, Ilia State University, K. Cholokoshvili Av. 3/5, Tbilisi 0162, Georgia (United States); Molotov, Igor E. [Keldysh Institute of Applied Mathematics, RAS, Miusskaya 4, Moscow 125047 (Russian Federation); Pray, Donald [Sugarloaf Mountain Observatory, South Deerfield, MA 01373 (United States); Husárik, Marek [Astronomical Institute of the Slovak Academy of Sciences, SK-059 60 Tatranska Lomnica (Slovakia); Pollock, Joseph T. [Physics and Astronomy Department, Appalachian State University, 525 Rivers St, Boone, NC 28608 (United States); Nesvorný, David, E-mail: vokrouhl@cesnet.cz [Department of Space Studies, Southwest Research Institute, 1050 Walnut Street, Suite 300, Boulder, CO 80302 (United States)

    2016-03-15

    The Schulhof family, a tight cluster of small asteroids around the central main belt body (2384) Schulhof, belongs to a so far rare class of very young families (estimated ages less than 1 Myr). Characterization of these asteroid clusters may provide important insights into the physics of the catastrophic disruption of their parent body. The case of the Schulhof family has been up to now complicated by the existence of two proposed epochs of its origin. In this paper, we first use our own photometric observations, as well as archival data, to determine the rotation rate and spin axis orientation of the largest fragment (2384) Schulhof. Our data also allow us to better constrain the absolute magnitude of this asteroid, and thus also improve the determination of its geometric albedo. Next, using the up-to-date catalog of asteroid orbits, we perform a new search of smaller members in the Schulhof family, increasing their number by 50%. Finally, the available data are used to access Schulhof's family age anew. We now find that the younger of the previously proposed two ages of this family is not correct, resulting from a large orbital uncertainty of single-opposition members. Our new runs reveal a single age solution of about 800 kyr with a realistic uncertainty of 200 kyr.

  6. The puzzling origin of the genetic code.

    Science.gov (United States)

    Cedergren, R; Miramontes, P

    1996-06-01

    Recent results add to the mystery of the origin of the genetic code. In spite of early doubts, RNA can discriminate between hydrophobic amino acids under certain contexts. Moreover, codon reassignment, which has taken place in several organisms and mitochondria, is not a random process. Finally, phylogenies of some aminoacyl-tRNA synthetases suggest that the entire code was not completely assigned at the time of the divergence of bacteria from nucleated cells.

  7. Rare Disasters, Credit, and Option Market Puzzles

    DEFF Research Database (Denmark)

    Christoffersen, Peter; Du, Du; Elkamhi, Redouane

    2016-01-01

    calibrated to the real economy can simultaneously explain several key empirical regularities in equity, credit, and options markets. Our model captures the empirical level and volatility of credit spreads, generates a flexible credit risk term structure, and provides a good fit to a century of observed...

  8. The electron screening puzzle and nuclear clustering

    Energy Technology Data Exchange (ETDEWEB)

    Spitaleri, C., E-mail: spitaleri@lns.infn.it [Department of Physics and Astronomy, University of Catania, Catania (Italy); INFN-Laboratori Nazionali del Sud, Catania (Italy); Bertulani, C.A. [Department of Physics and Astronomy, Texas A& M University-Commerce, Commerce, TX 75429 (United States); Department of Physics and Astronomy, Texas A& M University, College Station, TX 77843 (United States); Fortunato, L.; Vitturi, A. [Dipartimento di Fisica e Astronomia “Galileo Galilei”, Università di Padova, via Marzolo, 8, I-35131 Padova (Italy); INFN, Sezione di Padova, via Marzolo, 8, I-35131 Padova (Italy)

    2016-04-10

    Accurate measurements of nuclear reactions of astrophysical interest within, or close to, the Gamow peak show evidence of an unexpected effect attributed to the presence of atomic electrons in the target. The experiments need to include an effective “screening” potential to explain the enhancement of the cross sections at the lowest measurable energies. Despite various theoretical studies conducted over the past 20 years and numerous experimental measurements, a theory has not yet been found that can explain the cause of the exceedingly high values of the screening potential needed to explain the data. In this letter we show that instead of an atomic physics solution of the “electron screening puzzle”, the reason for the large screening potential values is in fact due to clusterization effects in nuclear reactions, in particular for reaction involving light nuclei.

  9. Solving a 3D structural puzzle

    DEFF Research Database (Denmark)

    Hoeck, Casper

    to spatial structural information using NMR spectroscopy. Experimental distances from nuclear Overhauser effect (NOE) correlations, and dihedral angles from 3JHH-coupling constants, were used to obtain 3D structural information for several natural and synthetic compounds. The stereochemistry of novel natural...... samples, which allows for RDCs to be extracted. The number of internuclear vectors for the correlation of RDCs to 3D structures is often limited for small molecules. Homonuclear RDCs were extracted by use of the homonuclear S3 HMBC that correlated well to alignment tensors from 1DCH-coupling constants......-calculation of RDCs from 3D structures was developed and tested, which copes better with multiple conformers than the commonly used SVD methodology. The approach thus resulted in good conformer populations for several small molecules, including multiple cinchona alkaloids....

  10. ESA's Cluster solved an auroral puzzle

    Science.gov (United States)

    2003-05-01

    These aurorae - seen as bright spots in Earth’s atmosphere and called ‘dayside proton auroral spots’ - occur when fractures appear in the Earth’s magnetic field, allowing particles given out from the Sun to squirt through and collide with the molecules in our atmosphere. This is the first time that a precise and direct connection between the two events has been made. The Earth’s magnetic field acts like a shield, protecting Earth from the constant stream of tiny particles ejected by the Sun and known as the ‘solar wind’. The solar wind itself is made of hydrogen atoms, broken into their constituent pieces: protons and electrons. When electrons find routes into our atmosphere, they collide with and excite the atoms in the air. When these excited atoms release their energy, it is given out as light, creating the glowing ‘curtains’ we see as the aurora borealis (or the aurora australis in the southern hemisphere). Dayside proton auroral spots are caused by protons ‘stealing’ electrons from the atoms in our atmosphere. On 18 March last year, a jet of energetic solar protons collided with the Earth’s atmosphere and created a bright ‘spot’ seen by NASA’s IMAGE spacecraft, just as Cluster passed overhead and straight through the region where the proton jet was emanating. An extensive analysis of the Cluster results has now shown that the region was experiencing a turbulent event known as ‘magnetic reconnection’. Such a phenomenon takes place when the Earth’s usually impenetrable magnetic field fractures and has to find a new stable configuration. Until the field mends itself, solar protons leak through the gap and jet into Earth’s atmosphere creating the dayside proton aurora. Philippe Escoubet, ESA’s Cluster Project Scientist, comments, “Thanks to Cluster’s observations scientists can directly and firmly link for the first time a dayside proton auroral spot and a magnetic reconnection event.” Tai Phan, leading the investigation at the University of California, Berkeley, United States, now looks forward to a new way of studying the Earth’s protective shield. He says, “This result has opened up a new area of research. We can now watch dayside proton aurorae and use those observations to know where and how the cracks in the magnetic field are formed and how long the cracks remain open. That makes it a powerful tool to study the entry of the solar wind into the Earth’s magnetosphere.” The Earth’s interaction with the Sun is a current focus of scientific attention because of its importance in knowing how the Sun affects the Earth, most notably our climate. Also, while not immediately dangerous to us on Earth, it is also important for quantifying the danger to satellites, which can be damaged or destroyed by powerful solar flares. Note to Editors: Proton aurorae were globally imaged for the first time by NASA’s IMAGE spacecraft. The images revealed the presence of the ‘dayside proton auroral spots’. By a fortunate coincidence, IMAGE and Cluster both spotted the event on 18 March 2002. Combining with IMAGE’s observations, Cluster made it possible to establish the ground truth of the phenomenon. The paper on these results, Simultaneous Cluster and IMAGE Observations of Cusp Reconnection and Auroral Spot for Northward IMF by Tai Phan and 24 other authors will be published in Geophysical Research Letters, 21 May 2003, Vol. 30, No. 10. The principal investigators responsible for the instruments that made these results possible are: Henri Rème of CESR/Toulouse, France (Cluster Proton Detectors), Andre Balogh of Imperial College, London, United Kingdom (Cluster Magnetic Field Instrument) and Stephen Mende of University of California, Berkeley, United States (IMAGE/FUV). More about Cluster ESA’s Cluster is a collection of four spacecraft, launched on two Russian rockets during the summer of 2000. They are now flying in formation around the Earth, relaying the most detailed ever information about how the solar wind affects our planet in 3D. The solar wind is the perpetual stream of subatomic particles given out by the Sun and it can damage communications satellites and power stations on the Earth. The Cluster mission is expected to continue until at least 2005. Cluster is part of the International Living with a Star programme (ILWS), in which space agencies worldwide get together to investigate how variations in the Sun affect the environment of Earth and the other planets. In particular, ILWS concentrate on those aspects of the Sun-Earth system that may affect mankind and society. ILWS is a collaborative initiative between Europe, the United States, Russia, Japan and Canada.

  11. Piecing together the biggest puzzle of all.

    Science.gov (United States)

    Rees, M J

    2000-12-08

    In this month's essay, the last in the Pathways of Discovery series, Martin J. Rees celebrates the way astronomers and cosmologists have systematically uncovered the biography of the universe. Rife with neutron stars, black holes, and multiple universes that emerge from quantum fluctuation, it's a story as grand as it is strange.

  12. New pieces of the Trichinella puzzle.

    Science.gov (United States)

    Pozio, Edoardo; Zarlenga, Dante S

    2013-11-01

    Contrary to our understanding of just a few decades ago, the genus Trichinella now consists of a complex assemblage of no less than nine different species and three additional genotypes whose taxonomic status remains in flux. New data and methodologies have allowed advancements in detection and differentiation at the population level which in turn have demonstrably advanced epidemiological, immunological and genetic investigations. In like manner, molecular and genetic studies have permitted us to hypothesise biohistorical events leading to the worldwide dissemination of this genus, and to begin crystalising the evolution of Trichinella on a macro scale. The identification of species in countries and continents otherwise considered Trichinella-free has raised questions regarding host adaptation and associations, and advanced important findings on the biogeographical histories of its members. Using past reviews as a backdrop, we have ventured to present an up-to-date assessment of the taxonomy, phylogenetic relationships and epidemiology of the genus Trichinella with additional insights on host species, survival strategies in nature and the shortcomings of our current understanding of the epidemiology of the genus. In addition, we have begun compiling information available to date on genomics, proteomics, transcriptomics and population studies of consequence in the hope we can build on this in years to come.

  13. A Puzzled DME Industry In China

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Over the recent years,the DME industry in China has gained higher speed,something like a blowout.However,it needs time to foster the market and there are some problems with the industry itself. These were among the topics at the Third International Conference on DME & Fifth Asian DME Conference held recently in Shanghai.

  14. The B --> K$*\\psi$ polarization puzzle

    CERN Document Server

    Aleksan, Roy; Oliver, L; Pène, O; Raynal, J C; Le Yaouanc, A; Oliver, L; Pene, O; Raynal, J C

    1994-01-01

    We point out that current estimates of form factors fail to explain the non-leptonic decays B \\to \\psi K(K^{\\ast}) and that the combination of data on the semi-leptonic decays D \\to K(K^{\\ast})\\ell \

  15. Puzzles in practice: splenic vein thrombosis.

    Science.gov (United States)

    McIntyre, Brittany; Marsh, Melanie; Walden, Jeffrey

    2016-06-01

    This report details a 58-year-old gentleman who presented to his outpatient primary care physician's clinic several times over four weeks for ongoing epigastric pain radiating into his left flank, dry heaving, and constipation. He was presumed to have gastritis at each visit and prescribed escalating doses of proton pump inhibitors. Due to the unrelenting pain, he eventually was admitted to the hospital and diagnosed with splenic vein thrombosis after computed tomography imaging of the abdomen. Our literature search revealed that pancreatic pathology is overwhelmingly the contributing factor to splenic vein thrombosis. Our patient had prominent collateral vasculature, suggesting that his splenic vein thrombosis was chronic in nature and likely the cause of his ongoing abdominal pain. Splenic vein thrombosis is an uncommon cause of abdominal pain, but one that should be included in the treating physician's differential diagnoses when abdominal pain is ongoing despite medical therapy. Although he had no evidence of initial findings on radiography, our patient was eventually diagnosed with biopsy-proven pancreatic cancer. Our case report demonstrates how patients presenting with persistent or worsening abdominal pain despite the use of proton pump inhibitors or other acid reducing agents and potential 'red flag' findings such as decreased appetite and weight loss should be worked up for other potential sources of abdominal pathology.

  16. The governance of problems: puzzling, powering, participation

    NARCIS (Netherlands)

    Hoppe, Robert

    2010-01-01

    Policy analysis usually gives more attention to problem solving than problem finding and there is a real threat of mismatch between problem perceptions by citizens and problem definition by their elected and appointed policy makers. Contemporary democracies need to develop a better governance of pro

  17. A possible explanation of the CP puzzle

    Energy Technology Data Exchange (ETDEWEB)

    Takhtamyshev, Georgij [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil)]|[Joint Inst. for Nuclear Research, Dubna (Russian Federation)

    1996-03-01

    The problem of mirror-reflection symmetry (MRS) and time-reversal symmetry (TRS) in our world is discussed. The opinion is expressed, that well-known experiments on parity violation and CP-violation can be treated as signals of some new, yet unknown, level of matter. An hypothesis, which can be used as a base for some future model or theory is formulated. In the framework of this hypothesis, experiments will demonstrate parity violation or CP-violation do not contradict MRS or TRS conservation. (author). 14 refs.

  18. Nursing education: current themes, puzzles and paradoxes.

    Science.gov (United States)

    Tanner, Christine A

    2007-01-01

    It would be tempting to declare that transformation of nursing education in the current context of faculty shortages and other scarce resources as Mission Impossible. But I believe that the opposite is true. It is my sense that the rapid changes in healthcare, the shifting population needs and the acute nursing shortage have catalyzed fundamental change, perhaps the most profound in the 50 year history of WIN. The first steps of that transformation are becoming increasingly apparent as nursing faculty begin to challenge their long-standing, taken-for-granted assumptions; as they set aside differences and their internecine warfare of the entry-into-practice debates; as they begin stronger and deeper collaborations with their clinical partners. We won't see the evidence of these changes in the literature for a while, because they are just getting started. There's not a lot to report yet. Here are some examples of the changes afoot: The Oregon Consortium for Nursing Education has resulted from unprecedented collaboration between community college and university faculty, with an eye to develop a standard, competency-based curriculum to prepare the "new" nurse, and to improve access to a seamless baccalaureate curriculum. The first students were enrolled in nursing courses in fall, 2006 on 8 campuses--the four campuses of OHSU and 4 community colleges, with additional community college campuses admitting students in '07 and '08. In this curriculum, fundamentals of nursing have been redefined as evidence-based practice, culturally sensitive and relationship-centered care, leadership and clinical judgment, with these concepts and others introduced early and spiraled throughout the curriculum. Through a 2-year faculty development program, faculty leaders in the OCNE partner programs have taken to heart the many lessons about learning, intentionally attending to content selection that will help reduce the volume while focusing on the most prevalent. Instructional approaches have been tremendously changed, with an emphasis on case-based instruction, integrating distance delivery technologies, and using simulation, drawing on best practices in the development of these approaches (Billings, et al., 2001; Issenberg, et al .2005; Jeffries, 2005). OCNE leaders obtained funding from Kaiser Permanente Northwest to begin the long, collaborative, consensus building process to transform clinical education. Evaluation has and will continue to be an integral part of this work, with an eye to adding to our collective knowledge of best practices in nursing education. We see evidence of similar efforts, mostly state or regional, in order to build on prior alliances, acknowledge geographic particularities, and respond to local needs in many other parts of the country, from Hawaii to New Jersey, Texas to Montana. The nursing shortage has been a primary catalyst. It has captured the interest of potential funders, individual donors, foundations to the Federal government. The keys are collaboration and a collective voice for nursing, a willingness to work through long-standing and divisive issues, and most importantly, a moral commitment to the populations we serve.

  19. Abortion in Vietnam: measurements, puzzles, and concerns.

    Science.gov (United States)

    Goodkind, D

    1994-01-01

    This report summarizes current knowledge about abortion in Vietnam, drawing upon government statistics, survey data, and fieldwork undertaken by the author in Vietnam throughout 1993 and part of 1994. The official total abortion rate in Vietnam in 1992 was about 2.5 per woman, the highest in Asia and worrisome for a country with a still-high total fertility rate of 3.7 children per woman. Vietnamese provinces exhibited substantial variation in both the rate of abortion and the type of procedures performed. Among the hypotheses explored to explain Vietnam's high rate of abortion are the borrowing of family planning strategies from other poor socialist states where abortion is common; current antinatal population policies that interact with a lack of contraceptive alternatives; and a rise in pregnancies among young and unmarried women in the wake of recent free-market reforms. Because family-size preferences are still declining, abortion rates may continue to increase unless the incidence of unwanted pregnancy can be reduced, a goal that Vietnamese population specialists are seeking to achieve.

  20. Serotonin, amygdala and fear: assembling the puzzle

    Directory of Open Access Journals (Sweden)

    Marco eBocchio

    2016-04-01

    Full Text Available The fear circuitry orchestrates defense mechanisms in response to environmental threats. This circuitry is evolutionarily crucial for survival, but its dysregulation is thought to play a major role in the pathophysiology of psychiatric conditions in humans. The amygdala is a key player in the processing of fear. This brain area is prominently modulated by the neurotransmitter serotonin (5-hydroxytryptamine, 5-HT. The 5-HT input to the amygdala has drawn particular interest because genetic and pharmacological alterations of the 5-HT transporter (5-HTT affect amygdala activation in response to emotional stimuli. Nonetheless, the impact of 5-HT on fear processing remains poorly understood.The aim of this review is to elucidate the physiological role of 5-HT in fear learning via its action on the neuronal circuits of the amygdala. Since 5-HT release increases in the BLA during both fear memory acquisition and expression, we examine whether and how 5-HT neurons encode aversive stimuli and aversive cues. Next, we describe pharmacological and genetic alterations of 5-HT neurotransmission that, in both rodents and humans, lead to altered fear learning.To explore the mechanisms through which 5-HT could modulate conditioned fear, we focus on the rodent basolateral amygdala (BLA. We propose that a circuit-based approach taking into account the localization of specific 5-HT receptors on neurochemically-defined neurons in the BLA may be essential to decipher the role of 5-HT in emotional behavior. In keeping with a 5-HT control of fear learning, we review electrophysiological data suggesting that 5-HT regulates synaptic plasticity, spike synchrony and theta oscillations in the BLA via actions on different subcellular compartments of principal neurons and distinct GABAergic interneuron populations. Finally, we discuss how recently developed optogenetic tools combined with electrophysiological recordings and behavior could progress the knowledge of the mechanisms underlying 5-HT modulation of fear learning via action on amygdala circuits. Such advancement could pave the way for a deeper understanding of 5-HT in emotional behavior in both health and disease.

  1. Serotonin, Amygdala and Fear: Assembling the Puzzle

    OpenAIRE

    Bocchio, Marco; McHugh, Stephen B.; Bannerman, David M; Sharp, Trevor; Capogna, Marco

    2016-01-01

    The fear circuitry orchestrates defense mechanisms in response to environmental threats. This circuitry is evolutionarily crucial for survival, but its dysregulation is thought to play a major role in the pathophysiology of psychiatric conditions in humans. The amygdala is a key player in the processing of fear. This brain area is prominently modulated by the neurotransmitter serotonin (5-hydroxytryptamine, 5-HT). The 5-HT input to the amygdala has drawn particular interest because genetic an...

  2. 物理学中的世纪难题:高能宇宙线的起源之"谜"%UNSOLVED PHYSICS PUZZLE IN THE LAST CENTURY: WHAT ARE SOURCES OF HIGH ENERGY COSMIC RAYS

    Institute of Scientific and Technical Information of China (English)

    曹臻; 刘加丽; 白云翔

    2009-01-01

    Since they were found in the 1920s, cosmic rays have been being investigated thoroughly for lo-cating their sources. It is still one of 11 unsolved puzzles that drive people to work hard in their own fields.Neutral components of the cosmic rays, photons and neutrinos are naturally selected as messengers between the source objects in the universe and us. It is also found that even if the ordinary charged cosmic ray parti-cles can be used as such a messenger as long as their energies are sufficiently high, e.g. above 50EeV.Large scale experiments in those fields form a frontier of a campaign for searching for the sources. Gamma ray astronomy seems to be the most successful and most likely to break through. For keeping the strong momentum, a significant boost in sensitivity of survey observational power with wide field of view instru-ment is essential. The international observatory at Tibet, China has developed well with two major experi-ments, ARGO-YBJ and AS_γ, collaborating with Italy and Japan with the right techniques, namely air shower observation. We propose building a large complex array with five components at Yang Ba Jing, Ti-bet to boost the source survey sensitivity. Details about physics perspectives and tentative design are dis-cussed in this paper.%自从上世纪20年代宇宙线被发现以来,其起源问题一直为人们所困惑.这一未解之谜也因此被列入21世纪11大科学难题之中.在宇宙线起源的探寻中,不受磁场偏转影响的中性成分(如光子和中微子)很自然的成为宇宙线源头的信使.此外,通过测量受磁场影响微小的高能(>50 EeV)带电粒子,也可以获取源的信息.通过大量的实验研究,γ天文学取得了巨大成就,并有望破解世纪之谜.为了提高地面探测器的观测能力,发展宽视场和高灵敏度的巡天扫描探测手段有着至关重要的意义.位于我国西藏羊八井国际观测站的两个实验所采用的正是这种大气簇射的测量方

  3. 新闻媒体关于中国奥运“金牌迷局”舆论引导的应有认识与作为%The Study on Media Guidance of Public Opinion on China's Olympic Gold Medal Puzzle

    Institute of Scientific and Technical Information of China (English)

    刘璐

    2012-01-01

    The Olympic Games will be held in London several months later,and the Youth Olympic Games is being undertaken its preparatory work in Nanjing smoothly.At the special moment,our Chinese news media should take the issue of Gold Medal Puzzle of Chinese Olympic Games into sincere consideration,and analyzes its reason from several perspectives,such as the system for sports games,the function of media and the establishment of medals.Only in this way can the media take its responsibility to create a sound atmosphere for the development of human beings' Olympic cause.%在伦敦奥运会即将召开、南京"青奥会"积极筹备之际,新闻媒体应当注意审视中国奥运"金牌迷局"的事实,从体育体制、媒体功用、奖牌设置等方面进行分析引导,以促使人类奥林匹克事业的健康发展。

  4. Determination of the torsion angles of alanine and glycine residues of model compounds of spider silk (AGG){sub 10} using solid-state NMR methods

    Energy Technology Data Exchange (ETDEWEB)

    Ashida, Jun; Ohgo, Kosuke; Komatsu, Kohei; Kubota, Ayumi; Asakura, Tetsuo [Tokyo University of Agriculture and Technology, Department of Biotechnology (Japan)], E-mail: asakura@cc.tuat.ac.jp

    2003-02-15

    Spiders synthesize several kinds of silk fibers. In the primary structure of spider silk, one of the major ampullate (dragline, frame) silks, spidroin 1, and flagelliform silk (core fibers of adhesive spiral), there are common repeated X-Gly-Gly (X = Ala, Leu, Pro, Tyr, Glu, and Arg) sequences, which are considered to be related to the elastic character of these fibers. In this paper, two dimensional spin diffusion solid-state NMR under off magic angle spinning (OMAS), {sup 13}C chemical shift contour plots, and Rotational Echo DOuble Resonance (REDOR) were applied to determine the torsion angles of one Ala and two kinds of Gly residues in the Ala-Gly-Gly sequence of {sup 13}C=O isotope-labeled (Ala-Gly-Gly){sub 10}. The torsion angles were determined to be ({phi}, {psi}) = (-90 deg., 150 deg.) within an experimental error of {+-}10 deg. for each residue. This conformation is characterized as 3{sub 1} helix which is in agreement with the structure proposed from the X-ray powder diffraction pattern of poly(Ala-Gly-Gly). The 3{sub 1} helix of (Ala-Gly-Gly){sub 10} does not change by formic acid treatment although (Ala-Gly){sub 15} easily changes from the silk I conformation (the structure of Bombyx mori silk fibroin before spinning in the solid state) to silk II conformation (the structure of the silk fiber after spinning) by such treatment. Thus, the 3{sub 1} helix conformation of (Ala-Gly-Gly){sub 10} is considered very stable. Furthermore, the torsion angles of the 16th Leu residue of (Leu-Gly-Gly){sub 10} were also determined as ({phi}, {psi}) = (-90 deg., 150 deg.) and this peptide is also considered to take 3{sub 1} helix conformation.

  5. 我国创新人才培养与思维方式转型进路--从李约瑟难题到钱学森之问%Education of Innovative Talents and Strategy of Thinking Mode Transition:From Joseph Needham Puzzle to Qian Xuesen’ s Question

    Institute of Scientific and Technical Information of China (English)

    何孟杰

    2016-01-01

    李约瑟难题与钱学森之问的核心都是创新人才培养问题。而思维方式是创新人才的核心要素,中国传统思维方式重类比、模糊与整体,西方思维方式重演绎、精确与分析;二者的差异是中国近现代科技发展和创新人才培养落后的一个重要原因。因此解决创新人才培养问题的一个关键是变革思维方式,变革的当务之急为融会中西思维方式,长期展望则需占领认知科学高地。%Joseph Needham Puzzle and Qian Xuesen ’ s Question are mainly concerned about the education of innovative talents, and the mode of thinking has played a key role in both questions. The mode of thinking in the West attaches importance to logical deduction, accuracy, mechanical and analysis, while the traditional mode of thinking in China pays more attention to analogy, fuzziness and the organic integrity. The history of science and technology shows that these differences can be described as one of the main reasons for the backwardness in education of creative talents in modern China. The key to solving the problem in innovative talents education is to transform the mode of thinking, for which we must take two steps. The first step is to popularize the thinking tools that are absorbed from the best of China and West, and the other one is to strategically stay in the forefront research field of thinking.

  6. The Energy Puzzle Between the United States and China

    Science.gov (United States)

    2013-03-01

    around mainland China. Figure 3. Source: U.S. Energy Information Administration The expansion of China in its crude oil production and exports...ranks fourth behind Iran in crude oil production , which accounts for more than 5.4% of the world’s crude oil consumption. However, China’s output of

  7. Corporate culture: the missing piece of the healthcare puzzle.

    Science.gov (United States)

    Waldman, J Deane; Smith, Howard L; Hood, Jacqueline N

    2003-01-01

    The U.S. healthcare system requires radical, not incremental, change. Management issues in healthcare delivery are fundamentally different from those in the business world. Systems thinking forces a focus on corporate culture, about which there is little hard data. The use of cost/benefit analysis suffers from the lack of any accepted measure of long-term "benefit." The authors make four observations: (1) corporate culture is both part of the cause and part of the cure for healthcare; (2) long-term financial and functional measures are necessary to make evidence-based decisions; (3) valid, nationwide data must be developed regarding the corporate culture of medicine; and (4) direct (unmodified) application of management theory or practices will not achieve sustainable improvements.

  8. The equatorial F-layer: progress and puzzles

    Directory of Open Access Journals (Sweden)

    H. Rishbeth

    Full Text Available This work reviews some aspects of the ionospheric F-layer in the vicinity of the geomagnetic equator. Starting with a historical introduction, brief summaries are given of the physics that makes the equatorial ionosphere so interesting, concentrating on the large-scale structure rather than the smaller-scale instability phenomena. Several individual topics are then discussed, including eclipse effects, the asymmetries of the `equatorial trough', variations with longitude, the semiannual variation, the effects of the global thermospheric circulation, and finally the equatorial neutral thermosphere, including `superrotation' and possible topographic influences.

    Keyword: Ionosphere (equatorial ionosphere

  9. 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...

  10. Puzzles of the dark energy in the universe - phantom

    CERN Document Server

    Dabrowski, Mariusz P

    2014-01-01

    This paper is devoted to some simple approach based on general physics tools to describe the physical properties of a hypothetical particle which can be the source of dark energy in the Universe known as phantom. Phantom is characterized by the fact that it possesses negative momentum and kinetic energy and that it gives large negative pressure which acts as antigravity. We consider phantom harmonic oscillator in comparison to a standard harmonic oscillator. By using the first law of thermodynamics we explain why the energy density of the Universe grows when it is filled with phantom. We also show how the collision of phantom with a standard particle leads to exploration of energy from the former by the latter (i.e. from phantom to the standard) if their masses are different. The most striking of our conclusions is that the collision of phantom and standard particles of the same masses is impossible unless both of them are at rest and suddenly start moving with the opposite velocities and kinetic energies. Th...

  11. Characterizing intestinal stem cells. An important part of the puzzle

    NARCIS (Netherlands)

    Schepers, A.G.A.P.

    2012-01-01

    The aim of this thesis is to gain better understanding of intestinal stem cells in normal and malignant conditions. In chapter 2 we take our first steps in the characterization of intestinal stem cells. We determine that they have telomerase activity but still suffer from telomere loss. In addition

  12. Anomaly Puzzle, Curved-Spacetime Spinor Hamiltonian, and String Phenomenology

    CERN Document Server

    Huang, Xing

    2011-01-01

    In the first part of this dissertation, we study two different aspects of string phenomenology. First we discuss the complementary signals of low mass superstrings at the proposed electron-positron facilities (ILC and CLIC), in e+e- and {\\gamma} {\\gamma} collisions. We examine all relevant four-particle amplitudes evaluated at the center of mass energies near the mass of lightest Regge excitations and extract the corresponding pole terms. Secondly, we consider string realizations of the Randall-Sundrum effective theory and explore the search for the lowest massive Regge excitation of the gluon and of the extra (color singlet) gauge boson inherent of D-brane constructions. We also study the ratio of dijet mass spectra at small and large scattering angles. We show that with the first fb-1 such a ratio can probe lowest-lying Regge states for masses ~3.0 TeV. Finally, we propose that the 3.2$\\sigma$ excess at about $140 {\\rm GeV}$ in the dijet mass spectrum of $W$ + jets reproted by the CDF Collaboration originat...

  13. Some issues concerning the proton charge radius puzzle

    CERN Document Server

    Walcher, Thomas

    2012-01-01

    An explanation of the difference of the charge radius of the proton as determined from the Lamb shift in electronic hydrogen and from elastic electron scattering off the proton on the one side and the recent high precision determination with muonic hydrogen on the other side is presented. It is shown that the modification of the $2S_{1/2}$ and $2P_{3/2}$ wave functions by the "Uehling potential" yields a correction to the theoretical Lamb shift of $\\delta (\\Delta E_{\\textrm{Lamb}}) = 0.302$ meV which has to be compared to $\\delta (\\Delta E_{\\textrm{Lamb}}) = 0.322(46)$ meV equivalent to the stated radius difference. The explanation is based on the realization that the bound state wave functions modified by the external "Uehling potential" have to be propagated by the vacuum polarization propagator in order to give the correct leading order Lamb shift. It is argued that a conflicting relativistic calculation neglects this propagation aspect. The explanation demonstrates that the Lamb shift is dynamically induc...

  14. Solving the puzzle of interstitial loop formation in bcc Iron.

    Science.gov (United States)

    Xu, Haixuan; Stoller, Roger E; Osetsky, Yury N; Terentyev, Dmitry

    2013-06-28

    The interstitial loop is a unique signature of radiation damage in structural materials for nuclear and other advanced energy systems. Unlike other bcc metals, two types of interstitial loops, 1/2 and , are formed in bcc iron and its alloys. However, the mechanism by which interstitial dislocation loops are formed has remained undetermined since they were first observed more than fifty years ago. We describe our atomistic simulations that have provided the first direct observation of loop formation. The process was initially observed using our self-evolving atomistic kinetic Monte Carlo method, and subsequently confirmed using molecular dynamics simulations. Formation of loops involves a distinctly atomistic interaction between two 1/2 loops, and does not follow the conventional assumption of dislocation theory, which is Burgers vector conservation between the reactants and the product. The process observed is different from all previously proposed mechanisms. Thus, our observations might provide a direct link between experiments and simulations and new insights into defect formation that may provide a basis to increase the radiation resistance of these strategic materials.

  15. Myocardial Dysfunction in Sepsis: A Large, Unsolved Puzzle

    Directory of Open Access Journals (Sweden)

    Constantino Jose Fernandes Jr.

    2012-01-01

    Full Text Available Sepsis has high incidence and mortality rates around the world. The role of cardiac depression in myocardial dysfunction during sepsis remains to be elucidated. This review attempts to summarize our understanding of the anatomical, histopathological, and pathophysiological mechanisms behind cardiac dysfunction. Biomarkers to detect cardiac depression have been used to recognize developing problems, but the actual impact of these tools remains unclear.

  16. THE REAL OPTIONS PUZZLE FOR MICHIGAN TART CHERRY PRODUCERS

    OpenAIRE

    Nyambane, Gerald G.; Black, J. Roy

    2004-01-01

    Capital budgeting decisions faced by tart cherry producers often challenge our traditional valuation techniques. Real Options Valuation (ROV) methods may be useful but assumptions of existing ROV approaches are restrictive and, in some cases, unrealistic. In this paper we assert that use of existing option pricing methods can not be justified. Instead, dynamic programming approach is more appropriate. We develop a multi-period model and use it to obtain an optimal orchard replacement policy. ...

  17. Is New Zealand vegetation really 'problematic'? Dansereau's puzzles revisited.

    Science.gov (United States)

    Wilson, J Bastow; Lee, William G

    2012-05-01

    Over four decades ago, Pierre Dansereau, the noted North American ecologist, proposed six features of New Zealand vegetation as being problematic or unusual in a global context. We examine his propositions in the light of current ecological knowledge to determine whether or not these can still be considered unusual characteristics of New Zealand vegetation. (1) 'Climatic change is still progressing' resulting in disequilibrium between species' distributions and the present climate. New data and methods of analysis now available have removed the impression that Dansereau gained of imprecise zonation, unclear vegetation/climate relations and missing vegetation types. Communities cited as having regeneration failure can now be seen as even-aged stands that developed after major disturbance, although there are other, also non-climatic, explanations. However, the cause of the Westland 'Nothofagus gap' has become more, rather than less, controversial. (2) 'Continuity of community composition defies classification' and 'Very few New Zealand associations have faithful species' are correct observations, but perhaps equally true of vegetation elsewhere. Dansereau's assertion of low species richness in New Zealand is not supported by the comparative data available. (3) 'Lack of intolerant [i.e. mid-seral] trees …' is not evident with newer information. The order of species in succession, seen as unclear by Dansereau, has been determined by a range of approaches, largely confirming each other. (4) 'Discrepancies of form and function …' in divaricate shrubs and widespread heteroblasty are still controversial, with many more explanations. Several abiotic explanations have failed to stand up to investigation. Explanations in terms of herbivory have been well supported, although the extinction of the large avian herbivores makes certainty impossible. (5) 'Incidence of hybridization …' remains problematic. We do not know whether the incidence is unusually high, as Dansereau alleged, but the limited comparative data available suggest not. (6) The 'overwhelming … competing power of exotics' is strongly context dependent. They are prominent in many non-forest habitats. It seems that they are drivers of the vegetation change in some habitats, yet passengers after disturbance in others. Invasions can be slow, and may still be very incomplete in some ecosystem types. Whether exotics will eventually take over in most communities, or whether the native species will 'laugh them to scorn' as Cockayne suggested, only time will tell. In conclusion, some aspects of New Zealand's vegetation seem less unusual with increased knowledge, but others remain 'problems'.

  18. Orangutan call communication and the puzzle of speech evolution

    NARCIS (Netherlands)

    Reis E Lameira, A.

    2013-01-01

    Speech is a human hallmark. However, its evolution is little understood. It remains largely unknown which features of the call communication of our closest relatives – great apes – may have constituted speech evolutionary feedstock. In this study, I investigate the extent to which speech building bl

  19. Safety of gene therapy: new insights to a puzzling case.

    Science.gov (United States)

    Rothe, Michael; Schambach, Axel; Biasco, Luca

    2014-01-01

    Over the last few years, the transfer of therapeutic genes via gammaretro- or lentiviral vector systems has proven its virtue as an alternative treatment for a series of genetic disorders. The number of approved phase I/II clinical trials, especially for rare diseases, is steadily increasing, but the overall hurdles to become a broadly acceptable therapy remain numerous. The efforts by clinicians and basic scientists have tremendously improved the knowledge available about feasibility and biosafety of gene therapy. Nonetheless, despite the generation of a plethora of clinical and preclinical safety data, we still lack sufficiently powerful assays to predictively assess the exact levels of toxicity that might be observed in any given clinical gene therapy. Insertional mutagenesis is one of the major concerns when using integrating vectors for permanent cell modification, and the occurrence of adverse events related to genotoxicity, in early gene therapy trials, has refrained the field of gene therapy from emerging further. In this review, we provided a comprehensive overview on the basic principles and potential co-factors concurring in the generation of adverse events reported in gene therapy clinical trials using integrating vectors. Additionally, we summarized the available systems to assess genotoxicity at the preclinical level and we shed light on the issues affecting the predictive value of these assays when translating their results into the clinical arena. In the last section of the review we briefly touched on the future trends and how they could increase the safety of gene therapy employing integrating vector technology to take it to the next level.

  20. Structural biology sheds light on the puzzle of genomic ORFans.

    Science.gov (United States)

    Siew, Naomi; Fischer, Daniel

    2004-09-10

    Genomic ORFans are orphan open reading frames (ORFs) with no significant sequence similarity to other ORFs. ORFans comprise 20-30% of the ORFs of most completely sequenced genomes. Because nothing can be learnt about ORFans via sequence homology, the functions and evolutionary origins of ORFans remain a mystery. Furthermore, because relatively few ORFans have been experimentally characterized, it has been suggested that most ORFans are not likely to correspond to functional, expressed proteins, but rather to spurious ORFs, pseudo-genes or to rapidly evolving proteins with non-essential roles. As a snapshot view of current ORFan structural studies, we searched for ORFans among proteins whose three-dimensional structures have been recently determined. We find that functional and structural studies of ORFans are not as underemphasized as previously suggested. These recently determined structures correspond to ORFans from all Kingdoms of life, and include proteins that have previously been functionally characterized, as well as structural genomics targets of unknown function labeled as "hypothetical proteins". This suggests that many of the ORFans in the databases are likely to correspond to expressed, functional (and even essential) proteins. Furthermore, the recently determined structures include examples of the various types of ORFans, suggesting that the functions and evolutionary origins of ORFans are diverse. Although this survey sheds some light on the ORFan mystery, further experimental studies are required to gain a better understanding of the role and origins of the tens of thousands of ORFans awaiting characterization.

  1. The Puzzle of a Marble in a Spinning Pipe

    Science.gov (United States)

    2015-05-01

    IOP Publishing Ltd C E Mungan 280 Physics Education May 2015 angle is r r/ .0 As a result, the green vector has a magnitude of ω ω=r r r r( )( / )0...ORGANIZATION NAME(S) AND ADDRESS(ES) US Naval Academy, Physics Department,Annapolis,MD,21402-1363 8. PERFORMING ORGANIZATION REPORT NUMBER 9. SPONSORING...298 (Rev. 8-98) Prescribed by ANSI Std Z39-18 Physics Education 50 (3) 279 1. Problem statement A marble is placed one-third of the length along a

  2. Ernst Moerk and the Puzzle of Zero-Trial Learning

    Science.gov (United States)

    Palmer, David C.

    2005-01-01

    In this article, the author shares an anecdote demonstrating one-trial learning which is commonplace in human behavior. The demonstration suggests that under some conditions, when people hear someone speak, their behavior changes, even in the absence of an apparent contingency of reinforcement, but only if they have in their repertoire verbal…

  3. Strangeness in nuclei and neutron stars: a challenging puzzle

    Directory of Open Access Journals (Sweden)

    Lonardoni Diego

    2016-01-01

    Full Text Available The prediction of neutron stars properties is strictly connected to the employed nuclear interactions. The appearance of hyperons in the inner core of the star is strongly dependent on the details of the underlying hypernuclear force. We summarize our recent quantum Monte Carlo results on the development of realistic two- and threebody hyperon-nucleon interactions based on the available experimental data for light- and medium-heavy hypernuclei.

  4. FTire and puzzling tyre physics: teacher, not student

    Science.gov (United States)

    Gipser, Michael

    2016-04-01

    By means of some instructive examples, the contribution shows how even complex phenomena and relations in tyre physics are better understood by using a physics-based tyre simulation model like FTire. In contrast to approximation-based phenomenological models, such an approach will give insight into, rather than requiring description of, the tyre's behaviour. Examples studied here comprise * predicted influence of wheel load, inflation pressure, camber angle, and slow rolling speed on parking torque, * predicted influence of inflation pressure on cornering stiffness and pneumatic trail, * relaxation length: ramping up and down slip angle and wheel load, * handling characteristic on very rough roads, * a strange phenomenon: cleats that 'attract' a tyre. Related to these studies, user-friendly simulation tools on the basis of FTire are introduced, which help in understanding the above-mentioned complex tyre properties. One of these tools, being valuable both in teaching and for vehicle/tyre dynamics experts in industry and research, allows the user to interactively modify, during a running simulation, tyre geometry, material data, and operating conditions. The impact of these variations both on tyre forces and moments as well as on internal tyre states can be directly seen in a running animation, and later analysed with a large variety of post-processing tools. Animations for all case studies are available for download on http://www.cosin.eu/animations. All registered trademarks used here are properties of their respective owners.

  5. Investigating the Puzzling Synchrotron Behaviour of Mrk 421

    Directory of Open Access Journals (Sweden)

    Maria I. Carnerero

    2016-11-01

    Full Text Available We investigate the multiwavelength behaviour of the high-energy peaked BL Lac object (HBL Mrk 421 at redshift z = 0 . 031 in the period 2007–2015. We use optical photometric, spectroscopic, and polarimetric data and near-infrared data obtained by 35 observatories participating in the GLAST-AGILE Support Program (GASP of the Whole Earth Blazar Telescope (WEBT, as well as by the Steward Observatory Support of the Fermi Mission. We also employ high-energy data from the Swift (UV and X-rays satellite to study correlations among emission in different bands.

  6. Massive Stars: Key to Solving the Cosmic Puzzle

    CERN Document Server

    Wofford, Aida; Walborn, Nolan R; Smith, Myron; Peña-Guerrero, María; Bianchi, Luciana; Thilker, David; Hillier, John D; Apellániz, Jesús Maíz; García, Miriam; Herrero, Artemio

    2012-01-01

    We describe observations in the nearby universe (<100 Mpc) with a 10-m or larger space-based telescope having imaging and spectral capabilities in the range 912-9000 \\AA that would enable advances in the fields of massive stars, young populations, and star-forming galaxies, that are essential for achieving the Cosmic Origins Program objectives i) how are the chemical elements distributed in galaxies and dispersed in the circumgalactic and intergalactic medium; and ii) when did the first stars in the universe form, and how did they influence their environments. We stress the importance of observing hundreds of massive stars and their descendants individually, which will make it possible to separate the many competing factors that influence the observed properties of these systems (mass, composition, convection, mass-loss, rotation rate, binarity, magnetic fields, and cluster mass).

  7. CMS completes major part of 3-D puzzle

    CERN Multimedia

    2002-01-01

    The assembly of CMS in the giant SX5 surface building at Cessy has reached an important turning point. The magnet return yoke - whose red 'wheels' and 'disks' dominate the scene within the building - is completely assembled, including the central part that supports the huge outer shell of the solenoid vacuum tank. Now the focus is shifting towards installing the coil and sub-detectors within this structure..

  8. Solving the $R_{AA}\\otimes v_2$ puzzle

    CERN Document Server

    Noronha-Hostler, Jacquelyn

    2016-01-01

    For the past ten years $R_{AA}(p_T)$, the nuclear modification factor that encodes the suppression of high $p_T$ particles due to energy loss within the medium was fairly well described by many theoretical models. However, the same models systematically under-predicted the high $p_T$ elliptic flow, $v_2$, which is experimentally measured as the correlation between soft and hard hadrons. All previous calculations neglected the effect of event-by-event fluctuations of an expanding viscous hydrodynamical background as well as the soft-hard flow harmonic correlations in the experimentally measured $v_2$. In this talk I show how event-by-event viscous hydrodynamics (computed using the v-USPhydro code) coupled to an energy loss model (BBMG) is able to simultaneously describe soft physics observables as well as the high-$p_T$ $R_{AA}$ and $v_2$. Suggestions for future more differential calculations at the LHC run2 are made to explore soft-hard flow correlations.

  9. Pull or Push? Octopuses Solve a Puzzle Problem.

    Directory of Open Access Journals (Sweden)

    Jonas N Richter

    Full Text Available Octopuses have large brains and exhibit complex behaviors, but relatively little is known about their cognitive abilities. Here we present data from a five-level learning and problem-solving experiment. Seven octopuses (Octopus vulgaris were first trained to open an L shaped container to retrieve food (level 0. After learning the initial task all animals followed the same experimental protocol, first they had to retrieve this L shaped container, presented at the same orientation, through a tight fitting hole in a clear Perspex partition (level 1. This required the octopuses to perform both pull and release or push actions. After reaching criterion the animals advanced to the next stage of the test, which would be a different consistent orientation of the object (level 2 at the start of the trial, an opaque barrier (level 3 or a random orientation of the object (level 4. All octopuses were successful in reaching criterion in all levels of the task. At the onset of each new level the performance of the animals dropped, shown as an increase in working times. However, they adapted quickly so that overall working times were not significantly different between levels. Our findings indicate that octopuses show behavioral flexibility by quickly adapting to a change in a task. This can be compared to tests in other species where subjects had to conduct actions comprised of a set of motor actions that cannot be understood by a simple learning rule alone.

  10. Telescopes versus Microscopes: the puzzle of Iron-60

    CERN Document Server

    Williams, Jonathan P

    2008-01-01

    The discovery that the short-lived radionucleide iron-60 was present in the oldest meteorites suggests that the formation of the Earth closely followed the death of a massive star. I discuss three astrophysical origins: winds from an AGB star, injection of supernova ejecta into circumstellar disks, and induced star formation on the boundaries of HII regions. I show that the first two fail to match the solar system iron-60 abundance in the vast majority of star forming systems. The cores and pillars on the edges of HII regions are spectacular but rare sites of star formation and larger clumps with masses 1e3-1e4 solar masses at tens of parsec from a supernova are a more likely birth environment for our Sun. I also examine gamma-ray observations of iron-60 decay and show that the Galactic background could account for the low end of the range of meteoritic measurements if the massive star formation rate was at least a factor of 2 higher 4.6 Gyr ago.

  11. Is the proton radius puzzle an evidence of extra dimensions?

    CERN Document Server

    Dahia, F

    2015-01-01

    The proton charge radius inferred from muonic hydrogen spectroscopy is not compatible with the previous value given by CODATA-2010, which, on its turn, essentially relies on measurements of the electron-proton interaction. The proton's new size was extracted from the 2S-2P Lamb shift in the muonic hydrogen, which showed an energy excess of 0.3 meV in comparison to the theoretical prediction, evaluated with the CODATA radius. Higher-dimensional gravity is a candidate to explain this discrepancy, since the muon-proton gravitational interaction is stronger than the electron-proton interaction and, in the context of braneworld models, the gravitational potential can be hugely amplified in short distances when compared to the Newtonian potential. Motivated by these ideas, we study a muonic hydrogen confined in a thick brane. We show that the muon-proton gravitational interaction modified by extra dimensions can provide the additional separation of 0.3 meV between 2S and 2P states. In this scenario, the gravitation...

  12. Applying Occam's Razor To The Proton Radius Puzzle

    Science.gov (United States)

    Higinbotham, Douglas

    2016-09-01

    Over the past five decades, ever more complex mathematical functions have been used to extract the radius of the proton from electron scattering data. For example, in 1963 the proton radius was extracted with linear and quadratic fits of low Q2 data (Lamb shift measurements.

  13. Pathophysiology of septic encephalopathy--an unsolved puzzle.

    Science.gov (United States)

    Flierl, Michael A; Rittirsch, Daniel; Huber-Lang, Markus S; Stahel, Philip F

    2010-01-01

    The exact cellular and molecular mechanisms of sepsis-induced encephalopathy remain elusive. The breakdown of the blood-brain barrier (BBB) is considered a focal point in the development of sepsis-induced brain damage. Contributing factors for the compromise of the BBB include cytokines and chemokines, activation of the complement cascade, phagocyte-derived toxic mediators, and bacterial products. To date, we are far from fully understanding the neuropathology that develops as a secondary remote organ injury as a consequence of sepsis. However, recent studies suggest that bacterial proteins may readily cross the functional BBB and trigger an inflammatory response in the subarachnoid space, in absence of a bacterial invasion. A better understanding of the pathophysiological events leading to septic encephalopathy appears crucial to advance the clinical care for this vulnerable patient population.

  14. The puzzle of decreased homeostatic slow wave sleep in aging

    OpenAIRE

    Rytkönen, Kirsi-Marja

    2012-01-01

    Slow wave sleep is the most important part of sleep, yet it decreases with aging. Staying awake puts pressure on the neurons of the brain s arousal systems, e.g. on the cortically projecting neurons of the basal forebrain. During wakefulness, these neurons are active and excite the cortex, thereby enhancing behavioral arousal. Sleep quality and duration are compromised with increasing age. Elderly people often experience these symptoms as sleep problems and contact medical professionals. Trea...

  15. Models in Insurance: Paradigms, Puzzles, Communications and Revolutions.

    Science.gov (United States)

    1980-06-01

    Models in Light of Futurism," 229-242. [80.22] A. Martinez, "Interpretaci6n del Fen6mino Actuarial mediante un Proceso Estocastico Evolutivo de Variables... Teoria della Credibilit&," Giornale dell’ Istituto degli Attuari, 27, 219-231 (1964). (D51 N. De Pril, "The Efficiency of a Bonus-Malus System," AB, 10

  16. The PRad experiment and the proton radius puzzle

    Directory of Open Access Journals (Sweden)

    Gasparian Ashot

    2014-06-01

    Full Text Available New results from the recent muonic hydrogen experiments seriously questioned our knowledge of the proton charge radius, rp. The new value, with its unprecedented less than sub-percent precision, is currently up to eight standard deviation smaller than the average value from all previous experiments, triggering the well-known “proton charge radius puzzle” in nuclear and atomic physics. The PRad collaboration is currently preparing a novel, magnetic-spectrometer-free ep scattering experiment in Hall B at JLab for a new independent rp measurement to address this growing “puzzle” in physics.

  17. Quality assurance and technology assessment: pieces of a larger puzzle.

    Science.gov (United States)

    McDonald, I G

    2000-01-01

    Increasing integration of health care and health services research has resulted in an overlap between disciplines involved in the evaluation of clinical practice. We have examined the relationships of quality assurance (QA), medical technology assessment (TA), clinical epidemiology (CE) and evidence-based medicine (EBM) from an historical perspective. Clinicians, patients and administrators need local information on effectiveness of routine care. Information from trials alone, efficacy data, will not suffice nor can it be culled from administrative databases designed for other purposes. The current activities of QA should be therefore be expanded to include the study of the effectiveness of interventions in terms of appropriateness of use, patient outcomes and study of the determinants of outcomes, as seen from the perspective of doctors, patients, administrators and policy makers, using data collected during the course of routine patient care. With the assistance of information technology, with methodological support and multidisciplinary cooperation, clinicians can do this as part of a more broadly defined clinical research. Quality assurance and TA both evolved with the objective of studying clinical care but have quite different historical roots, complementary perspectives and objectives, use different methods and involve a different set of practitioners. Quality assurance is a type of 'formative' evaluation conducted in the clinical setting using indicators as flags of process or outcome events of interest, simple surveys and audit studies. Its primary aim is to achieve incremental improvement rather than to simply pass judgement. An important underlying assumption is that health care behaves as a complex dynamic system. Technology assessment, a form of summative evaluation with an orientation towards policy, synthesises information from formal scientific studies of efficacy in the form of clinical trials and studies of cost-effectiveness. For the evaluation of the impact of any technology more complex than a drug, the complementary contributions of both of these disciplines is needed, and QA and TA should work cooperatively in tandem with the support of CE and EBM.

  18. Veterans’ Policy in Russia: a Puzzle of Creation

    Directory of Open Access Journals (Sweden)

    Natalia Danilova

    2007-12-01

    Full Text Available Every war creates a new “lost generation”, veterans of wars and military operations. After the end of wars, states develop different ways of rewarding ex-soldiers for their service to the state. This paper analyzes veterans’ policy in the Soviet Union, its transformation after the collapse of the Soviet Union and the new veterans’ policy in modern Russia. The paper reviews different historical stages in developing a veterans’ policy, and examines the main differences among the population of veterans. It outlines how the position of the most preferred group, the veterans of the Great Patriotic War, is supported by politics and expressed in civil-military relations. Further, the paper shows the gradual development in the welfare of veterans for other subgroups of veterans. In conclusion, it discusses the consequences of the modern veterans’ system in Russia.

  19. Osteoprotegerin in bone metastases: mathematical solution to the puzzle.

    Directory of Open Access Journals (Sweden)

    Marc D Ryser

    Full Text Available Bone is a common site for cancer metastasis. To create space for their growth, cancer cells stimulate bone resorbing osteoclasts. Cytokine RANKL is a key osteoclast activator, while osteoprotegerin (OPG is a RANKL decoy receptor and an inhibitor of osteoclastogenesis. Consistently, systemic application of OPG decreases metastatic tumor burden in bone. However, OPG produced locally by cancer cells was shown to enhance osteolysis and tumor growth. We propose that OPG produced by cancer cells causes a local reduction in RANKL levels, inducing a steeper RANKL gradient away from the tumor and towards the bone tissue, resulting in faster resorption and tumor expansion. We tested this hypothesis using a mathematical model of nonlinear partial differential equations describing the spatial dynamics of OPG, RANKL, PTHrP, osteoclasts, tumor and bone mass. We demonstrate that at lower expression rates, tumor-derived OPG enhances the chemotactic RANKL gradient and osteolysis, whereas at higher expression rates OPG broadly inhibits RANKL and decreases osteolysis and tumor burden. Moreover, tumor expression of a soluble mediator inducing RANKL in the host tissue, such as PTHrP, is important for correct orientation of the RANKL gradient. A meta-analysis of OPG, RANKL and PTHrP expression in normal prostate, carcinoma and metastatic tissues demonstrated an increase in expression of OPG, but not RANKL, in metastatic prostate cancer, and positive correlation between OPG and PTHrP in metastatic prostate cancer. The proposed mechanism highlights the importance of the spatial distribution of receptors, decoys and ligands, and can be applied to other systems involving regulation of spatially anisotropic processes.

  20. The puzzle of coeliac disease: pieces of the molecular pathogenesis

    NARCIS (Netherlands)

    Diosdado Calvo, María Begoña

    2006-01-01

    Coeliac disease (CD) is a chronic intolerance to a dietary protein called gluten. This protein is present in common cereals such as wheat, barley and rye, and it is needed to prepare the derivate products such as bread or pasta. CD only occurs in individuals that carry certain altered genes. The ide

  1. The puzzle of chloroplast vesicle transport – involvement of GTPases

    Directory of Open Access Journals (Sweden)

    Sazzad eKarim

    2014-09-01

    Full Text Available In the cytosol of plant cells vesicle transport occurs via secretory pathways among the endoplasmic reticulum (ER network, Golgi bodies, secretory granules, endosome and plasma membrane. Three systems transfer lipids, proteins and other important molecules through aqueous spaces to membrane-enclosed compartments, via vesicles that bud from donor membranes, being coated and uncoated before tethered and fused with acceptor membranes. In addition, molecular, biochemical and ultrastructural evidence indicates presence of a vesicle transport system in chloroplasts. Little is known about the protein components of this system. However, as chloroplasts harbour the photosynthetic apparatus that ultimately supports most organisms on the planet, close attention to their pathways is warranted. This may also reveal novel diversification and/or distinct solutions to the problems posed by the targeted intra-cellular trafficking of important molecules. To date two homologues to well-known yeast cytosolic vesicle transport proteins, CPSAR1 and CPRabA5e, have been shown to have roles in chloroplast vesicle transport, both being GTPases. Bioinformatic data indicate that several homologues of cytosolic vesicle transport system components are putatively chloroplast-localized and in addition other proteins have been implicated to participate in chloroplast vesicle transport, including vesicle-inducing protein in plastids 1 (VIPP1, thylakoid formation 1 (THF1, snowy cotyledon 2/cotyledon chloroplast biogenesis factor (SCO2/CYO1, curvature thylakoid 1 (CURT1 proteins, and a dynamin like GTPase FZO-like (FZL protein. Several putative potential cargo proteins have also been identified, including building blocks of the photosynthetic apparatus. Here we discuss details of the largely unknown putative chloroplast vesicle transport system, focusing on GTPase-related components.

  2. On asset pricing and the equity premium puzzle

    OpenAIRE

    2000-01-01

    This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University. Presented here are consumption and production related asset pricing models which seek to explain stock market behaviour through the stock premium over risk-free bonds and to do so using parameter values consistent with theory. Our results show that there are models capable of explaining stock market behaviour. For the consumption-based model, we avoid many of the suggestions to artificiall...

  3. A Nitration Reaction Puzzle for the Organic Chemistry Laboratory

    Science.gov (United States)

    Wieder, Milton J.; Barrows, Russell

    2008-01-01

    Treatment of phenylacetic acid with 90% HNO[subscript 3] yields a product, I, whose observed melting point is 175-179 degrees C and whose equivalent weight is approximately 226 grams. Treatment of phenylacetic acid with 70% HNO[subscript 3] yields a product, II, whose observed melting point is 106-111 degrees C and whose equivalent weight is…

  4. Effective field theory investigations of the XYZ puzzle

    Science.gov (United States)

    Segovia, Jorge

    2016-08-01

    Quantum Chromodynamics, the theory of strong interactions, predicts several types of bound states. Among them are conventional mesons (qq̅) and baryons (qqq), which have been the only states observed in experiments for years. However, in the last decade, many states that do not fit this picture have been observed at B-factories (BaBar, Belle and CLEO), at τ-charm facilities (CLEO-c, BESIII) and also at proton-proton colliders (CDF, D0, LHCb, ATLAS, CMS). There is growing evidence that at least some of the new charmonium- and bottomonium-like states, the so-called XYZ mesons, are new forms of matter such as quark-gluon hybrids, mesonic molecules or different arrangements of tetraquarks, pentaquarks... Effective Field Theories (EFTs) have been constructed for heavy-quark-antiquark bound states, but a general study of the XYZ mesons within the same framework has not yet been done. The scope of this conference proceedings is to discuss the possibilities we have in developing novel EFTs that, characterizing the conventional quarkonium states, facilitate also the systematic and model-independent description of the new exotic matter, in particular, the hybrid mesons.

  5. ADDing a piece to the puzzle of cognition in schizophrenia.

    Science.gov (United States)

    Bosia, Marta; Pigoni, Alessandro; Zagato, Laura; Merlino, Lino; Casamassima, Nunzia; Lorenzi, Cristina; Pirovano, Adele; Smeraldi, Enrico; Manunta, Paolo; Cavallaro, Roberto

    2016-01-01

    The biological bases of cognitive impairment in schizophrenia are poorly understood and may lie in insults in neurodevelopment, leading to alterations in critical structures. Synapses proteins are claimed to have etiopathogenic roles and more direct effects on core cognitive functions. Adducins family proteins seem of great interest, as they are fundamental constituents of synapses, involved in actin cytoskeleton assembly-disassembly, responsible of synaptic plasticity. ADD2 is more prominently expressed in brain tissues and influences memory and learning, commonly impaired in schizophrenia. In the present study we tested 342 patients with schizophrenia for three common adducins genetic variants, ADD1 rs4961, ADD2 rs4984 and ADD3 rs3731566, reported to have significant effects on circulatory system in humans. Neuropsychological measures were evaluated with the Brief Assessment of Cognition in Schizophrenia (BACS), a broad battery evaluating core cognitive domains. The analysis showed significant effects of ADD2 genotype on almost every cognitive domain. Moreover, significant interactions between ADD1 and ADD3 were also observed on some BACS subtests, namely Symbol Coding and Verbal Memory. Our findings suggest that adducins are involved in cognitive impairment in schizophrenia. This effect may result both from a direct mechanism affecting synaptic building and plasticity and indirectly as a consequence of vascular insults.

  6. Puzzle of "lost" reactor neutrinos solved by scientists

    CERN Multimedia

    2002-01-01

    A collaboration of Chinese, Japanese and American scientists have announced that electron antineutrinos from nuclear reactors escape detection by oscillating into another type of neutrino. The experiment confirms solar neutrino oscillation and determines the key parameters of neutrino oscillation (1/2 page).

  7. Serum cholesterol and depression: A puzzle never finished

    Directory of Open Access Journals (Sweden)

    Satish Kumar Budania

    2015-01-01

    Full Text Available Depression is a state of sadness, hopelessness, and discouragement. Various studies have been conducted to uncover the etiological factors involved in depression. Serum folic acid is one such factor. Many researchers have reported an inverse association between serum folic acid and depression. We did an extensive computerized database searches on PubMed, Medline, and EBSCO and found that low serum folic acid are associated with depression, not only in adults, but also in elderly and diabetic patients. Further augmentation of folic acid with antidepressant treatment also improves the treatment outcome in depressed patients. Hence, considering the high benefits to the adverse effects ratio of serum folic acid, its supplementation should be done in "at risk" population whenever possible.

  8. The puzzle of kidney dysfunction in heart failure: an introduction.

    Science.gov (United States)

    Metra, Marco; Voors, Adriaan A

    2012-03-01

    Heart failure and kidney disease often coexist, and each of the two conditions may lead to progression of the other. Kidney dysfunction is an independent prognostic factor in patients with either acute or chronic heart failure. Worsening renal function may be related with poorer outcomes as well. Multiple mechanisms are involved in the cardio-renal interaction, including hemodynamic abnormalities, neurohormonal and inflammatory activation, oxidative stress, anemia, and abnormalities in mineral and vitamin D metabolism. Serum creatinine has limitations for the assessment of kidney function in patients with heart failure as its short-term changes are dependent on hemodynamic changes and fluid status. New biomarkers of glomerular and tubular function might allow an earlier and more accurate detection of worsening renal function.

  9. Pull or Push? Octopuses Solve a Puzzle Problem

    Science.gov (United States)

    Richter, Jonas N.; Hochner, Binyamin; Kuba, Michael J.

    2016-01-01

    Octopuses have large brains and exhibit complex behaviors, but relatively little is known about their cognitive abilities. Here we present data from a five-level learning and problem-solving experiment. Seven octopuses (Octopus vulgaris) were first trained to open an L shaped container to retrieve food (level 0). After learning the initial task all animals followed the same experimental protocol, first they had to retrieve this L shaped container, presented at the same orientation, through a tight fitting hole in a clear Perspex partition (level 1). This required the octopuses to perform both pull and release or push actions. After reaching criterion the animals advanced to the next stage of the test, which would be a different consistent orientation of the object (level 2) at the start of the trial, an opaque barrier (level 3) or a random orientation of the object (level 4). All octopuses were successful in reaching criterion in all levels of the task. At the onset of each new level the performance of the animals dropped, shown as an increase in working times. However, they adapted quickly so that overall working times were not significantly different between levels. Our findings indicate that octopuses show behavioral flexibility by quickly adapting to a change in a task. This can be compared to tests in other species where subjects had to conduct actions comprised of a set of motor actions that cannot be understood by a simple learning rule alone. PMID:27003439

  10. Puzzles in quarkonium hadronic transitions with two pion emission

    CERN Document Server

    Fernández, F.; Ortega, P.G.; Entem, D.R.

    2016-01-01

    The anomalously large rates of some hadronic transitions from quarkonium are studied using QCD multipole expansion (QCDME) in the framework of a constituent quark model which has been successful in describing hadronic phenomenology. The hybrid intermediate states needed in the QCDME method are calculated in a natural extension of our constituent quark model based on the Quark Confining String (QCS) scheme. Some of the anomalies are explained due to the presence of an hybrid state with a mass near the mass of the decaying resonance whereas other are justified by the presence of molecular components in the wave function. Some unexpected results are pointed out.

  11. Extreme ultraviolet lithography: A few more pieces of the puzzle

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Christopher N. [Univ. of California, Berkeley, CA (United States)

    2009-05-20

    The work described in this dissertation has improved three essential components of extreme ultraviolet (EUV) lithography: exposure tools, photoresist, and metrology. Exposure tools. A field-averaging illumination stage is presented that enables nonuniform, high-coherence sources to be used in applications where highly uniform illumination is required. In an EUV implementation, it is shown that the illuminator achieves a 6.5% peak-to-valley intensity variation across the entire design field of view. In addition, a design for a stand-alone EUV printing tool capable of delivering 15 nm half-pitch sinusoidal fringes with available sources, gratings and nano-positioning stages is presented. It is shown that the proposed design delivers a near zero line-edge-rougness (LER) aerial image, something extremely attractive for the application of resist testing. Photoresist. Two new methods of quantifying the deprotection blur of EUV photoresists are described and experimentally demonstrated. The deprotection blur, LER, and sensitivity parameters of several EUV photoresists are quantified simultaneously as base weight percent, photoacid generator (PAG) weight percent, and post-exposure bake (PEB) temperature are varied. Two surprising results are found: (1) changing base weight percent does not significantly affect the deprotection blur of EUV photoresist, and (2) increasing PAG weight percent can simultaneously reduce LER and E-size in EUV photoresist. The latter result motivates the development of an EUV exposure statistics model that includes the effects of photon shot noise, the PAG spatial distribution, and the changing of the PAG distribution during the exposure. In addition, a shot noise + deprotection blur model is used to show that as deprotection blur becomes large relative to the size of the printed feature, LER reduction from improved counting statistics becomes dominated by an increase in LER due to reduced deprotection contrast. Metrology. Finally, this dissertation describes MOSAIC, a new wavefront metrology that enables complete wavefront recovery from print or aerial image based measurements. This new technique, based on measuring the local focal length of the optic at sampled positions in the pupil, recovers the curvature of the aberration and uses the curvature to recover the aberration itself. In a modeled EUV implementation, MOSAIC is shown to recover the SEMATECH Berkeley MET wavefront with a 4.2% RMS error: a 4% improvement over the reported errors of the original lateral shearing interferometry wavefront measurement.

  12. Building complex brains--missing pieces in an evolutionary puzzle.

    Science.gov (United States)

    Jaaro, Hanna; Fainzilber, Mike

    2006-01-01

    The mechanisms underlying evolution of complex nervous systems are not well understood. In recent years there have been a number of attempts to correlate specific gene families or evolutionary processes with increased brain complexity in the vertebrate lineage. Candidates for evocation of complexity include genes involved in regulating brain size, such as neurotrophic factors or microcephaly-related genes; or wider evolutionary processes, such as accelerated evolution of brain-expressed genes or enhanced RNA splicing or editing events in primates. An inherent weakness of these studies is that they are correlative by nature, and almost exclusively focused on the mammalian and specifically the primate lineage. Another problem with genomic analyses is that it is difficult to identify functionally similar yet non-homologous molecules such as different families of cysteine-rich neurotrophic factors in different phyla. As long as comprehensive experimental studies of these questions are not feasible, additional perspectives for evolutionary and genomic studies will be very helpful. Cephalopod mollusks represent the most complex nervous systems outside the vertebrate lineage, thus we suggest that genome sequencing of different mollusk models will provide useful insights into the evolution of complex brains.

  13. Language Impairments in Sign Language: Breakthroughs and Puzzles

    Science.gov (United States)

    Morgan, Gary; Herman, Rosalind; Woll, Bencie

    2007-01-01

    Background: Specific language impairment has previously solely been documented for children acquiring spoken languages, despite informal reports of deaf children with possible sign language disorder. The paper reports the case of a deaf child exposed to British Sign Language (BSL) from birth, who has significant developmental deficits in the…

  14. Cosmic update dark puzzles : arrow of time : future history

    CERN Document Server

    Adams, Fred; Mersini-Houghton, Laura; Nekoogar, Farzad

    2012-01-01

    "...The Multiversal book series is equally unique, providing book-length extensions of the lectures with enough additional depth for those who truly want to explore these fields, while also providing the kind of clarity that is appropriate for interested lay people to grasp the general principles involved." - Lawrence M. Krauss Cosmic Update covers: A novel approach to uncover the dark faces of the Standard Model of cosmology. The possibility that Dark Energy and Dark Matter are manifestations of the inhomogeneous geometry of our Universe. The history of cosmological model building and the general architecture of cosmological models. Illustrations of the Large Scale Structure of the Universe. A new perspective on the classical static Einstein Cosmos. Global properties of World Models including their Topology. The Arrow of Time in a Universe with a Positive Cosmological Constant. The exploration of the consequences of a fundamental Cosmological Constant for our Universe. The exploration of why the current ob...

  15. Health cost risk : A potential solution to the annuity puzzle

    NARCIS (Netherlands)

    Peijnenburg, J.M.J.; Nijman, Theo; Werker, Bas

    2016-01-01

    We find that health cost risk lowers optimal annuity demand at retirement. If medical expenses can be sizeable early in retirement, full annuitisation at retirement is no longer optimal because agents do not have enough time to build a liquid wealth buffer. Furthermore, large deviations from optimal

  16. The Iranian Puzzle Piece: Understanding Iran in the Global Context

    Science.gov (United States)

    2009-01-01

    institution focused on the art and science of war and is fully engaged in and dedicated to its students’ professional military education. Through...elite. If the ahmadinejad government maintains power, the country will be ruled by a small cartel of hard-line clerics and nouveau riche Islamic

  17. Internalized Racism: One More Piece of the Puzzle

    Science.gov (United States)

    Speight, Suzette L.

    2007-01-01

    In this issue, Robert T. Carter has made an important contribution to the literature in clinical psychologists understanding of the psychological injury caused by experiences of racism. However, Carter's focus on specific encounters with racism might be narrow and limited. The author of this reaction contends that racial incidents (i.e.,…

  18. RPA puzzle in ${^{12}C}$ weak decay processes

    CERN Document Server

    Krmpotic, F; Samana, A

    2002-01-01

    We explain the origin of the difficulties that appear in a straightforward application of the QRPA in ${^{12}C}$, and we demonstrate that it is imperative to use the projected QRPA (PQRPA). Satisfactory results, not only for the weak processes among the ground states of the triad $\\{{{^{12}B},{^{12}C},{^{12}N}}\\}$, but also for the inclusive ones are obtained. We sketch as well a new formalism for the neutrino-nucleus interaction that furnishes very simple final formulae for the muon capture rate and neutrino induced cross sections.

  19. Puzzles in bonding and spectroscopy: the case of dicarbon.

    Science.gov (United States)

    Macrae, Roderick M

    2016-01-01

    The unstable molecule C₂ has been of interest since its identification as the source of the "Swan band" features observable in the spectra offlames, carbon arcs, white dwarf stars, and comets, and it continues to serve as a focal point for experimental and theoretical discovery. Recent spectroscopic work has identified a quintet state of the molecule for the first time, while new insights into the bond order of C₂ in its ground state have been provided by sophisticated computational methods based on valence bond theory. This article gives a review of spectroscopic and computational work on C₂ including both historical background and the most recent discoveries.

  20. A puzzling millisecond pulsar companion in NGC 6266

    CERN Document Server

    Cocozza, G; Possenti, A; Beccari, G; Lanzoni, B; Ranson, S; Rood, R T; D'Amico, N

    2008-01-01

    We report on the optical identification of the companion to the eclipsing millisecond pulsar PSR J1701$-$3006B in the globular cluster NGC 6266. A relatively bright star with an anomalous red colour and an optical variability ($\\sim$ 0.2 mag) that nicely correlates with the orbital period of the pulsar ($\\sim$ 0.144 days) has been found nearly coincident with the pulsar nominal position. This star is also found to lie within the error box position of an X-ray source detected by Chandra observations, thus supporting the hypothesis that some interaction is occurring between the pulsar wind and the gas streaming off the companion. Although the shape of the optical light curve is suggestive of a tidally deformed star which has nearly completely filled its Roche lobe, the luminosity ($\\sim 1.9 L_\\odot$) and the surface temperature ($\\sim 6000$ K) of the star, deduced from the observed magnitude and colours, would imply a stellar radius significantly larger than the Roche lobe radius. Possible explanations for this...

  1. Fluorine abundances and the puzzle of globular cluster chemical history

    CERN Document Server

    de Laverny, P

    2013-01-01

    The abundance of fluorine in a few Galactic globular clusters is known to strongly vary from star-to-star. These unexpected chemical properties are an additional confirmation of the chemical inhomogeneities already found in several GC, and probably caused by the first generations of stars formed in these systems. The aim of this article is to complement our understanding of the F-behaviour in GC stars and to look for new constraints on the formation histories of their multiple stellar populations. We have collected near-IR spectra of 15 RGB stars belonging to GC spanning a wide range of metallicity: 47 Tuc, M4, NGC6397 and M30. F, Na and Fe abundances have been estimated by spectral synthesis. No anticorrelation between F and Na abundances are found for the most metal-rich cluster of the sample (47 Tuc). In this GC, RGB stars indeed exhibit rather small differences in [F/Fe] unlike the larger ones found for the [Na/Fe] ratios. This reveals a rather inhomogeneous stellar system and a complex chemical evolution...

  2. The puzzle of the lyman continuum polarization of qsos

    Directory of Open Access Journals (Sweden)

    Gregory A. Shields

    2001-01-01

    Full Text Available Mediante espectropolarimetr a reciente de cuasares se ha encontrado un sor- prendente incremento en la polarizaci on del cont nuo de Lyman en varios objetos. Discutimos algunos intentos recientes para explicar este hecho, que incluyen el papel de la absorci on de Lyman en PG 1222+228. Presentamos nuevos resultados te oricos que involucran dispersi on por electrones en una corona caliente o en un viento por encima de un disco de acreci on, y la polarizaci on que resulta del efecto relativista de la radiaci on que regresa. Potencialemente estos mecanismos pueden alcanzar niveles de polarizaci on observables en longitudes de onda cortas, pero ninguno logra ex- plicar cuantitativamente los incrementos en la polarizaci on del cont nuo de Lyman. Se requiere urgentemente mayor capacidad para llevar a cabo espectropolarimetr a en el ultravioleta desde sat elites para esclarecer este fen omeno.

  3. Bats and Emerging Infections: An Ecological and Virological Puzzle.

    Science.gov (United States)

    Serra-Cobo, Jordi; López-Roig, Marc

    2016-10-09

    More than 200 viruses have been detected in bats. Some unique bat characteristics can explain the roles played in the maintenance and transmission of viruses: long phylogenetic history can have originated coevolution processes, great number of species are adapted to live in different environments, big mobility, long lifespan and gregarious behaviour of many species.To analyse zoonoses long longitudinal studies are needed with a multidisciplinary approximation to obtain the following eco-epidemiological data: colony size, number of bats per species, population structure, behaviour of each species, degree of contact between bats, social structure, remaining time of bats in the colony, colony type, foraging area, turnover rate of individuals, shelter temperature, relationship with other colonies and co-infection processes. These data allows assessing the epidemiological risk and which preventive measures are necessary to take.The structure and functionality of ecosystems are changing worldwide at an unprecedented rate and can modify the interactions between humans and infected bats. There are more or less local factors that can affect the emergence and spread of diseases (environmental alterations, changes in land use, human population growth, changes in human socioeconomic behavior or social structure, people mobility increase, trade increase, forest fires, extreme weather events, wars, breakdown in public health infrastructure, etc.).Twenty-three percent of all bat species in the world are decreasing. How does the regression of bat species affect the dynamic of viruses? The dichotomy between health risk and bat preservation is compatible with a preventive task based on more information and training.

  4. Motivated information processing in organizational teams: Progress, puzzles, and prospects

    NARCIS (Netherlands)

    Nijstad, B.A.; de Dreu, C.K.W.

    2012-01-01

    Much of the research into group and team functioning looks at groups that perform cognitive tasks, such as decision making, problem solving, and innovation. The Motivated Information Processing in Groups Model (MIP-G; De Dreu, Nijstad, & Van Knippenberg, 2008) conjectures that information processing

  5. Monarch butterfly orientation: missing pieces of a magnificent puzzle

    Science.gov (United States)

    Brower

    1996-01-01

    From late August to early September, millions of adult monarch butterflies of the eastern North American population cease reproducing, become highly gregarious and begin migrating southwards. By mid-October, they migrate through central Texas into Mexico where they follow the Sierra Madre Oriental across the Tropic of Cancer. They then shift direction westwards towards the Transverse Neovolcanic Belt of mountains where they overwinter without breeding. A rapid exodus northwards occurs at the spring equinox, and by early April both sexes reach the Gulf Coast states where the females lay eggs on the resurgent spring milkweed (Asclepias) flora and die. Adults of the new generation continue the migration to the northernmost breeding range, arriving by early June. Two or more short-lived breeding generations are produced over the summer, spread eastwards across the Appalachian Mountains and, by September, the autumn migration is again under way. This paper presents a new hypothesis that the orientation of adult monarchs undergoes a continual clockwise shifting throughout the 3-5 generations, rotating by 360 in the course of the year. This hypothesis is consistent with the timing of arrivals and the relative abundances of the successive generations of monarchs throughout eastern North America, with the directions of movement of their spring, summer and autumn generations, and with the timing of their arrival at the overwintering area in central Mexico.

  6. On the puzzle of space weathering alteration of basaltic asteroids

    CERN Document Server

    Marchi, S; Lazzarin, M; Magrin, S

    2010-01-01

    The majority of basaltic asteroids are found in the inner main belt, although a few have also been observed in the outer main belt and near-Earth space. These asteroids -referred to as V-types- have surface compositions that resemble that of the 530km sized asteroid Vesta. Besides the compositional similarity, dynamical evidence also links many V-type asteroids to Vesta. Moreover, Vesta is one of the few asteroids to have been identified as source of specific classes of meteorites, the howardite, eucrite, diogenite achondrites (HEDs). Despite the general consensus on the outlined scenario, several questions remain unresolved. In particular, it is not clear if the observed spectral diversity among Vesta, V-types and HEDs is due to space weathering, as is thought to be the case for S-type asteroids. In this paper, SDSS photometry is used to address the question of whether the spectral diversity among candidate V-types and HEDs can be explained by space weathering. We show that visible spectral slopes of V-types...

  7. Solving puzzles of GW150914 by primordial black holes

    CERN Document Server

    Blinnikov, S; Porayko, N K; Postnov, K

    2016-01-01

    The black hole binary properties inferred from the LIGO gravitational wave signal GW150914 posed several serious problems. The high masses and low effective spin of black hole binary can be explained if they are primordial (PBH) rather than the products of the stellar binary evolution. Such PBH properties are postulated ad hoc but not derived from fundamental theory. We show that the necessary features of PBHs naturally follow from the slightly modified Affleck-Dine (AD) mechanism of baryogenesis. The log-normal distribution of PBHs, predicted within the AD paradigm, is adjusted to provide an abundant population of low-spin stellar mass black holes. The same distribution gives a sufficient number of quickly growing seeds of supermassive black holes observed at high redshifts and may comprise an appreciable fraction of Dark Matter which does not contradict any existing observational limits. Testable predictions of this scenario are discussed.

  8. How deep is the annuity market participation puzzle?

    OpenAIRE

    Inkmann, Joachim; Lopes, Paula; Michaelides, Alexander

    2007-01-01

    Using UK microeconomic data, we analyze the empirical determinants of voluntary annuity market demand. We find that annuity market participation increases with financial wealth, life expectancy and education and decreases with other pension income and a possible bequest motive for surviving spouses. We then show that these empirically-motivated determinants of annuity market participation have the same, quantitatively important, effects in a life-cycle model of annuity and life insurance dema...

  9. A reexamination of some puzzling results in linearized elasticity

    Indian Academy of Sciences (India)

    C S Jog; Harish P Cherukuri

    2014-02-01

    In this paper, we analyse three commonly discussed ‘flaws’ of linearized elasticity theory and attempt to resolve them. The first ‘flaw’ concerns cylindrically orthotropic material models. Since the work of Lekhnitskii (1968), there has been a growing body of work that continues to this day, that shows that infinite stresses arise with the use of a cylindrically orthotropicmaterial model even in the case of linearized elasticity. Besides infinite stresses, interpenetration of matter is also shown to occur. These infinite stresses and interpenetration occur when the ratio of the circumferential Young modulus to the radial Young modulus is less than one. If the ratio is greater than one, then the stresses at the center of a spinning disk are found to be zero (recall that for an isotropic material model, the stresses are maximum at the center). Thus, the stresses go abruptly from a maximum value to a value of zero as the ratio is increased to a value even slightly above one! One of the explanations provided for this extremely anomalous behaviour is the failure of linearized elasticity to satisfy material frameindifference. However, if this is the true cause, then the anomalous behaviour should also occur with the use of an isotropic material model, where, no such anomalies are observed.We show that the real cause of the problem is elsewhere and also show how these anomalies can be resolved. We also discuss how the formulation of linearized elastodynamics in the case of small deformations superposed on a rigid motion can be given in a succinct manner. Finally, we show how the long-standing problem of devising three compatibility relations instead of six can be resolved.

  10. Dengue disease diagnosis: A puzzle to be solved

    Directory of Open Access Journals (Sweden)

    Jaime Eduardo Castellanos

    2014-10-01

    Full Text Available Dengue is an infection caused by dengue virus and is the most important arthropod transmitted viral disease in the world, causing near 100 million cases and 50 000 fatalities each year. Health authorities believe that these numbers will grow in coming years. In Colombia, almost 600 municipalities are in regions with Aedes aegypti circulation, and the presence of four dengue serotypes has been demonstrated. Despite the increasing knowledge about disease pathogenesis and the dengue virus, some technical or scientific difficulties with diagnosing dengue remain, negatively affecting both public health surveillance and the appropriate attention to patients in health settings and hospitals. This paper reviews the principles and developments of the current diagnostic techniques for dengue, pointing out the difficulties with making accurate dengue diagnoses and case confirmations in public health and specialized laboratories. The principles and limitations of MAC-ELISA, IgG serology, viral NS1 detection and viral isolation by cell culture are presented. In addition, the review of immunochromatography techniques (rapid diagnostic tests that have been put forward to help the point-of-care diagnosis is proposed. This paper is intended to bring forward some points of view about the issues related to dengue diagnosis and contribute to improve the discussion surrounding the strategies and techniques needed for reducing the impact of the disease and favoring its control.

  11. The Puzzle of Muslim Advantage in Child Survival in India

    NARCIS (Netherlands)

    Bhalotra, S.; Valente, C.; van Soest, A.H.O.

    2009-01-01

    The socio-economic status of Indian Muslims is, on average, considerably lower than that of upper caste Hindus. Muslims have higher fertility and shorter birth spacing and are a minority group that, it has been argued, have poorer access to public goods. They nevertheless exhibit substantially highe

  12. The puzzling unidimensionality of DSM-5 substance use disorder diagnoses

    Directory of Open Access Journals (Sweden)

    Robert J MacCoun

    2013-11-01

    Full Text Available There is a perennial expert debate about the criteria to be included or excluded for the DSM diagnoses of substance use dependence. Yet analysts routinely report evidence for the unidimensionality of the resulting checklist. If in fact the checklist is unidimensional, the experts are wrong that the criteria are distinct, so either the experts are mistaken or the reported unidimensionality is spurious. I argue for the latter position, and suggest that the traditional reflexive measurement model is inappropriate for the DSM; a formative measurement model would be a more accurate characterization of the institutional process by which the checklist is created, and a network or causal model would be a more appropriate foundation for a scientifically grounded diagnostic system.

  13. Possible explanation of the solar-neutrino puzzle

    Science.gov (United States)

    Bethe, H. A.

    1986-01-01

    A new derivation of the Mikheyev and Smirnov (1985) mechanism for the conversion of electron neutrinos into mu neutrinos when traversing the sun is presented, and various hypotheses set forth. It is assumed that this process is responsible for the detection of fewer solar neutrinos than expected, with neutrinos below a minimum energy, E(m), being undetectable. E(m) is found to be about 6 MeV, and the difference of the squares of the respective neutrino masses is calculated to be 6 X 10 to the - 5th sq eV. A restriction on the neutrino mixing angle is assumed such that the change of density near the crossing point is adiabatic. It is predicted that no resonance conversion of neutrinos will occur in the dense core of supernovae, but conversion of electron neutrinos to mu neutrinos will occur as they escape outward through a density region around 100.

  14. One more piece of KGB puzzle put in place

    Index Scriptorium Estoniae

    2005-01-01

    Leedu parlamendi erikomisjon leidis, et KGB reservi arvatud isikute staatus erineb teistest organisatsiooni töötajate ja salaagentide omast. Komisjon jõudis järeldusele, et Antanas Valionise ja Arvydas Pociuse kunagine kuulumine KGB reservi ei kujuta endast ohtu Leedu rahvuslikule julgeolekule.

  15. Solving Enterprise Applications Performance Puzzles Queuing Models to the Rescue

    CERN Document Server

    Grinshpan, Leonid

    2012-01-01

    A groundbreaking scientific approach to solving enterprise applications performance problems Enterprise applications are the information backbone of today's corporations, supporting vital business functions such as operational management, supply chain maintenance, customer relationship administration, business intelligence, accounting, procurement logistics, and more. Acceptable performance of enterprise applications is critical for a company's day-to-day operations as well as for its profitability. Unfortunately, troubleshooting poorly performing enterprise applications has traditionally

  16. Thirty Years with HIV Infection-Nonprogression Is Still Puzzling

    DEFF Research Database (Denmark)

    Gaardbo, Julie C; Hartling, Hans J; Gerstoft, Jan;

    2012-01-01

    mechanisms. Understanding the lack of disease progression and the different interactions between HIV and the immune system could ideally teach us how to develop a functional cure for HIV infection. Here we review immunological features of controllers and LTNP, highlighting differences and clinical......In the early days of the HIV epidemic, it was observed that a minority of the infected patients did not progress to AIDS or death and maintained stable CD4+ cell counts. As the technique for measuring viral load became available it was evident that some of these nonprogressors in addition......, host differences in the immunological response have been proposed. Moreover, the immunological response can be divided into an immune homeostasis resistant to HIV and an immune response leading to viral control. Thus, non-progression in LTNP and controllers may be due to different immunological...

  17. Strangeness in nuclei and neutron stars: a challenging puzzle

    CERN Document Server

    Lonardoni, Diego; Gandolfi, Stefano; Pederiva, Francesco

    2015-01-01

    The prediction of neutron stars properties is strictly connected to the employed nuclear interactions. The appearance of hyperons in the inner core of the star is strongly dependent on the details of the underlying hypernuclear force. We summarize our recent quantum Monte Carlo results on the development of realistic two- and three-body hyperon-nucleon interactions based on the available experimental data for light- and medium-heavy hypernuclei.

  18. Strangeness in nuclei and neutron stars: a challenging puzzle

    Science.gov (United States)

    Lonardoni, Diego; Lovato, Alessandro; Gandolfi, Stefano; Pederiva, Francesco

    2016-03-01

    The prediction of neutron stars properties is strictly connected to the employed nuclear interactions. The appearance of hyperons in the inner core of the star is strongly dependent on the details of the underlying hypernuclear force. We summarize our recent quantum Monte Carlo results on the development of realistic two- and threebody hyperon-nucleon interactions based on the available experimental data for light- and medium-heavy hypernuclei.

  19. The APOSTLE simulations: solutions to the Local Group's cosmic puzzles

    CERN Document Server

    Sawala, Till; Fattahi, Azadeh; Navarro, Julio F; Bower, Richard G; Crain, Robert A; Vecchia, Claudio Dalla; Furlong, Michelle; Helly, John C; Jenkins, Adrian; Oman, Kyle A; Schaller, Matthieu; Schaye, Joop; Theuns, Tom; Trayford, James; White, Simon D M

    2015-01-01

    The Local Group of galaxies offer some of the most discriminating tests of models of cosmic structure formation. For example, observations of the Milky Way (MW) and Andromeda satellite populations appear to be in disagreement with N-body simulations of the "Lambda Cold Dark Matter" ({\\Lambda}CDM) model: there are far fewer satellite galaxies than substructures in cold dark matter halos (the "missing satellites" problem); dwarf galaxies seem to avoid the most massive substructures (the "too-big-to-fail" problem); and the brightest satellites appear to orbit their host galaxies on a thin plane (the "planes of satellites" problem). Here we present results from APOSTLE (A Project Of Simulating The Local Environment), a suite of cosmological hydrodynamic simulations of twelve volumes selected to match the kinematics of the Local Group (LG) members. Applying the Eagle code to the LG environment, we find that our simulations match the observed abundance of LG galaxies, including the satellite galaxies of the MW and ...

  20. The rise of C4 grassland ecosystems, a climate puzzle

    Science.gov (United States)

    Henderson, A.; Fox, D.; Freeman, K. H.

    2011-12-01

    The expansion of grasslands was one of the most profound ecological changes in the Cenozoic. Understanding the history of forest to grassland transitions, and the development of C4 grasslands in particular, is critical for understanding the relationship between land surface climate feedbacks, seasonality, and temperature. Modern distributions and ecological experiments demonstrate a strong correlation between C4 biogeography and high growing season temperatures and precipitation, as well as low pCO2 concentrations. The rise of C4 grasses in North America, as documented by carbonate nodule and mammal teeth δ13C values, began during a warm period with relatively stable pCO2 in the late Miocene. Surprisingly, C4 grasses continued to expand and then rose to dominance in the Great Plains as climates progressively cooled, moisture availability increased, and ice sheets formed further north on the continent. To understand this seemingly paradoxical scenario, we need constraints on the rate and character of increasing abundances of C4 vegetation. To this end, we use molecular and isotopic tools from terrestrial plant leaf wax n-alkanes extracted from carbonate nodules in the Meade Basin, Kansas and sites in Texas for the past 12 Ma. These records offer site-specific reconstructions tied directly to vegetation source. We compare our results to published continental-scale reconstructions of n-alkanes from the Mississippi River drainage basin and to climate records. From the distribution of C27 to C33 n-alkane abundances and patterns in δ13C values, we infer that C4 grasses coexisted with patches of C3 vegetation, including both grasses and trees. C4 grasses increasingly dominated the landscape, reaching modern abundances as ice sheets were reaching their southern limit in North America. Our results confirm that C4 grasslands emerged under cool and wet conditions, something we would not predict based on modern analogues, raising questions about our understanding of the climatic drivers on C4 vegetation distribution in the past.

  1. Intersectional puzzles: understanding inclusion and exclusion in political recruitment

    NARCIS (Netherlands)

    Celis, K.; Erzeel, S.; Mügge, L.

    2015-01-01

    Feminist scholars have developed a solid research agenda on gender equality in politics. This scholarship is built on the conviction that equitable representation of men and women is fundamental to the functioning of representative democracies (Mansbridge 1999; Norris and Lovenduski 1995). In order

  2. Near-IR imaging towards a puzzling YSO precessing jet

    CERN Document Server

    Paron, S; Ortega, M E

    2016-01-01

    At present there are many studies concerning jets towards low-mass young stellar objects, while equivalent studies towards massive or intermediate-mass young stellar objects are scarce. In a previous study, we found highly misaligned molecular outflows towards the infrared point source IRS. Using near-IR data acquired with Gemini-NIRI at the JHKs-broad-bands and narrow-bands centered at the emission lines of [FeII], H2 1-0 S(1), H2 2-1 S(1), Br-gamma, and CO 2-0 (bh), we studied the circumstellar environment of IRS with an angular resolution between 0.35" and 0.45". The emission in the JHKs-broad-bands shows, with great detail, the presence of a cone-like shape nebula extending to the north/northeast of the point source, which appears to be attached to it by a jet-like structure. In the three bands the nebula is resolved in a twisted-shaped feature composed by two arc-like features and a bow shock-like structure seen mainly in the Ks-band, which strongly suggests the presence of a precessing jet. An analysis ...

  3. Patsy Healey: "Puzzling towards people-oriented planning"

    NARCIS (Netherlands)

    Koolmees, T.; Koudstaal, M.; Majoor, S.

    2014-01-01

    Patsy Healey is one of the most prominent, productive and highly praised planning academics of our time. During her career, the connection between practice theory and normative perspectives on planning has been a central concern. As professor emeritus at Newcastle University, she recently became inv

  4. Spam:One Puzzled Problem for E-Commerce

    Institute of Scientific and Technical Information of China (English)

    FU Qiansheng; YANG Jingmin

    2004-01-01

    E-commerce has advantages of low bargaining cost, full field service, and convenient. Its development forms and promotes the key factor of the global economic growth, and the security problem of e-commerce becomes more and more important thereupon. It is the subject of a great meaning to structure the safe, convenient e-commerce running environment. The task of anti-spam is a concrete content among them. This paper discusses the source and danger of spam, and the precautionary and radical cure measures of spam are put forwarded, and the technologies of the anti-spam are discussed especially.

  5. Solving the puzzles of cutin and suberin polymer biosynthesis.

    Science.gov (United States)

    Beisson, Fred; Li-Beisson, Yonghua; Pollard, Mike

    2012-06-01

    Cutin and suberin are insoluble lipid polymers that provide critical barrier functions to the cell wall of certain plant tissues, including the epidermis, endodermis and periderm. Genes that are specific to the biosynthesis of cutins and/or aliphatic suberins have been identified, mainly in Arabidopsis thaliana. They notably encode acyltransferases, oxidases and transporters, which may have either well-defined or more debatable biochemical functions. However, despite these advances, important aspects of cutin and suberin synthesis remain obscure. Central questions include whether fatty acyl monomers or oligomers are exported, and the extent of extracellular assembly and attachment to the cell wall. These issues are reviewed. Greater emphasis on chemistry and biochemistry will be required to solve these unknowns and link structure with function.

  6. Solving GRBs and SGRs puzzles by precessing Jets

    CERN Document Server

    Fargion, D; Oliva, P

    2006-01-01

    A persistent, thin, micro-nano sr. beamed gamma jet, may be ejected from BH and Pulsars, powered by ultra-relativistic electron pairs. These jet while precessing and spinning are originated by Inverse Compton and-or Synchrotron Radiation at pulsars or micro-quasars sources. They are most powerful at Supernova birth, blazing, once on axis, to us and flashing GRB detector. The trembling of thin jets explains naturally the observed erratic multi-explosive structure of different GRBs. The jets are precessing and decaying on time scales of a few hours surviving as long as thousands of years, linking huge GRB-SN jet apparent Luminosity to more modest SGR relic Jets. Therefore long-life SGR may be repeating and if they are around our galaxy they might be observed again as the few known ones and a few rarer extragalactic XRFs. The orientation of the beam respect to the line of sight plays a key role in differentiating the wide GRB morphology. The relativistic cone is as small as the inverse of the electron progenitor...

  7. What makes you clever the puzzle of intelligence

    CERN Document Server

    Partridge, Derek

    2014-01-01

    From Black Holes and Big Bangs to the Higgs boson and the infinitesimal building blocks of all matter, modern science has been spectacularly successful, with one glaring exception - intelligence. Intelligence still remains as one of the greatest mysteries in science. How do you chat so effortlessly? How do you remember, and why do you forget? From a basis of ten maxims What Makes You Clever explains the difficulties as well as the persuasive and persistent over-estimations of progress in Artificial Intelligence. Computers have transformed our lives, and will continue to do so for many years to come. But ever since the Turing Test proposed in 1950 up to IBM's Deep Blue computer that won the second six-game match against world champion Garry Kasparov, the science of artificial intelligence has struggled to make progress. The reader's expertise is engaged to probe human language, machine learning, neural computing, holistic systems and emergent phenomenon. What Makes You Clever reveals the difficulties that s...

  8. The puzzle of kidney dysfunction in heart failure : an introduction

    NARCIS (Netherlands)

    Metra, Marco; Voors, Adriaan A.

    2012-01-01

    Heart failure and kidney disease often coexist, and each of the two conditions may lead to progression of the other. Kidney dysfunction is an independent prognostic factor in patients with either acute or chronic heart failure. Worsening renal function may be related with poorer outcomes as well. Mu

  9. The Azobenzene Optical Storage Puzzle - Demands on the Polymer Scaffold?

    DEFF Research Database (Denmark)

    Hvilsted, Søren; Ramanujam, PS

    2001-01-01

    The basic mechanism of optical information storage utilizing the azobenzene photoaddressable moiety will briefly be introduced. A synthetically flexible polyester matrix covalently integrating cyanoazobenzene in regularly spaced side chains is particularly well suited for holographic storage...... of the nature of the main chain on polyester morphology and on the permanency of the induced anisotropy are discussed. Arguments for the design and methods of preparation of other very different polymer scaffolds supporting the cyanoazobenzene are elucidated. Whereas oligopeptides invariably form amorphous...

  10. The azobenzene optical storage puzzle - Demands on the polymer scaffold?

    DEFF Research Database (Denmark)

    Hvilsted, Søren; Ramanujam, P.S.

    2001-01-01

    The basic mechanism of optical information storage utilizing the azobenzene photoaddressable moiety will briefly be introduced. A synthetically flexible polyester matrix covalently integrating cyanoazobenzene in regularly spaced side chains is particularly well suited for holographic storage...... of the nature of the main chain on polyester morphology and on the permanency of the induced anisotropy are discussed. Arguments for the design and methods of preparation of other very different polymer scaffolds supporting the cyanoazobenzene are elucidated. Whereas oligopeptides invariably form amorphous...

  11. An instrumental puzzle: the modular integration of AOLI

    CERN Document Server

    López, Roberto L; Colodro-Conde, Carlos; Valdivia, Juan J F; Puga, Marta; Oscoz, Alejandro; Rebolo, Rafael; Mackay, Craig; Pérez-Garrido, Antonio; Rodríguez-Ramos, Luis Fernando; Rodríguez-Ramos, José M; King, David; Labadie, Lucas; Muthusubramanian, Balaji; Rodríguez-Coira, Gustavo

    2016-01-01

    The Adaptive Optics Lucky Imager, AOLI, is an instrument developed to deliver the highest spatial resolution ever obtained in the visible, 20 mas, from ground-based telescopes. In AOLI a new philosophy of instrumental prototyping has been applied, based on the modularization of the subsystems. This modular concept offers maximum flexibility regarding the instrument, telescope or the addition of future developments.

  12. Hybrid Ameloblastoma of the Maxilla: A Puzzling Pathology

    Directory of Open Access Journals (Sweden)

    Chintamaneni Raja Lakshmi

    2016-07-01

    Full Text Available Ameloblastomas are slow growing, locally invasive, benign odontogenic tumors of an epithelial origin, accounting for approximately 1% of all oral tumors. A 40-year-old man presented with a chief complaint of a swelling over the left side of his face of 4 years’ duration. On examination, gross facial asymmetry was detected, and a well-defined swelling was noted intraorally involving the left maxilla medially from the mid palatal raphe and obliterating the buccal vestibule laterally. The swelling was non-tender and exhibited dual consistencies: firm in the palate and cystic in the vestibular region. Computed tomography revealed a multilocular radiolucency, which involved the left maxilla, encroached into the left maxillary sinus and the nasal complex, and caused bony erosion. Early diagnosis and treatment are the key tools in managing ameloblastomas, failure of which may lead to a significant deterioration of the prognosis and an increased recurrence rate. Uncommon variants of ameloblastomas have been gaining interest recently. To date, 25 cases of hybrid ameloblastomas have been documented in the scientific literature. We present an extremely rare hybrid type of the ameloblastoma with combined follicular, cystic, acanthomatous, and desmoplastic variants, which render it the first of its kind to have ever been reported.

  13. Gastrotricha: A Marine Sister for a Freshwater Puzzle

    OpenAIRE

    M Antonio Todaro; Matteo Dal Zotto; Ulf Jondelius; Rick Hochberg; Hummon, William D.; Tobias Kånneby; Carlos E. F. Rocha

    2012-01-01

    BACKGROUND: Within an evolutionary framework of Gastrotricha Marinellina flagellata and Redudasys fornerise bear special interest, as they are the only Macrodasyida that inhabit freshwater ecosystems. Notwithstanding, these rare animals are poorly known; found only once (Austria and Brazil), they are currently systematised as incertae sedis. Here we report on the rediscovery of Redudasys fornerise, provide an account on morphological novelties and present a hypothesis on its phylogenetic rela...

  14. The olfactory system as a puzzle: playing with its pieces.

    Science.gov (United States)

    Díaz, D; Gómez, C; Muñoz-Castañeda, R; Baltanás, F; Alonso, J R; Weruaga, E

    2013-09-01

    The mammalian olfactory bulb (OB) has all the features of a whole mammalian brain but in a more reduced space: neuronal lamination, sensory inputs, afferences, or efferences to other centers of the central nervous system, or a contribution of new neural elements. Therefore, it is widely considered as "a brain inside the brain." Although this rostral region has the same origin and general layering as the other cerebral cortices, some distinctive features make it very profitable in experimentation in neurobiology: the sensory inputs are driven directly on its surface, the main output can be accessed anatomically, and new elements appear in it throughout adult life. These three morphological characteristics have been manipulated to analyze further the response of the whole OB. The present review offers a general outlook into the consequences of such experimentation in the anatomy, connectivity and neurochemistry of the OB after (a) sensory deprivation, mainly by naris occlusion; (b) olfactory deinnervation by means of olfactory epithelium damage, olfactory nerve interruption, or even olfactory tract disruption; (c) the removal of the principal neurons of the OB; and (d) management of the arrival of newborn interneurons from the rostral migratory stream. These experiments were performed using surgical or chemical methods, but also by means of the analysis of genetic models, some of whose olfactory components are missing, colorless or mismatching within the wild-type scenario of odor processing.

  15. On the New Puzzling Results from MiniBooNE

    CERN Document Server

    Abbas, Syed Afsar

    2011-01-01

    We look into the recent puzzlng results from MiniBooNE and contrast their results with that from NOMAD. A pictuire which provides consistent decscriptiobn of both is discussed here. This also points to future directions in neutrino studies.

  16. Molecular structures in the charmonium spectrum: the XYZ puzzle

    Science.gov (United States)

    Ortega, P. G.; Entem, D. R.; Fernández, F.

    2013-06-01

    We study in the framework of a constituent quark model the possible contributions of molecular structures to the XYZ charmonium-like states. We analyze simultaneously the c\\bar{c} structures and the possible molecular components in the coupled channel formalism. In the 1++ sector two states appear which could be identified with X(3872) and X(3940). The recently confirmed X(3915) state appears as a mixture of c\\bar{c} and D\\bar{D} components as a JPC = 0++ state in agreement with the new measurements. A second broad resonance which may correspond with the so-called Y(3940) state is found with these quantum numbers. In the JPC = 1-- sector we also found significant contributions of the molecular structures which may affect the phenomenology. In particular the study allows us to understand the G(3900) state recently observed in Belle and BaBar. All these resonances together with the prediction of the model of a c\\bar{c} structure for Z(3930) provide a reasonable scenario for the so-called XYZ states with masses near 3.9 GeV.

  17. Puzzles of J/{Psi} production off nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Kopeliovich, B.Z., E-mail: boris.kopeliovich@mpi-hd.mpg.d [Departamento de Fisica, Universidad Tecnica Federico Santa Maria, and Instituto de Estudios Avanzados en Ciencias e Ingenieria, and Centro Cientifico-Tecnologico de Valparaiso, Casilla 110-V, Valparaiso (Chile)

    2011-03-15

    Nuclear effects for J/{Psi} production in pA collisions are controlled by the coherence and color transparency effects. Color transparency onsets when the time of formation of the charmonium wave function becomes longer than the inter-nucleon spacing. In this energy regime the effective break-up cross section for a c-barc dipole depends on energy and nuclear path length, and agrees well with data from fixed target experiments, both in magnitude and energy dependence. At higher energies of RHIC and LHC coherence in c-barc pair production leads to charm quark shadowing which is a complement to the high twist break up cross section. These two effects explain well with no adjusted parameters the magnitude and rapidity dependence of nuclear suppression of J/{Psi} observed at RHIC in dAu collisions, while the contribution of leading twist gluon shadowing is found to be vanishingly small. A novel mechanism of double color filtering for c-barc dipoles makes nuclei significantly more transparent in AA compared to pA collisions. This is one of the mechanisms which make impossible a model independent 'data driven' extrapolation from pA to AA. This effect also explains the enhancement of nuclear suppression observed at forward rapidities in AA collisions at RHIC, what hardly can be related to the produced dense medium. J/{Psi} is found to be a clean and sensitive tool measuring the transport coefficient characterizing the dense matter created in AA collisions. RHIC data for p{sub T} dependence of J/{Psi} production in nuclear collisions are well explained with the low value of the transport coefficient q-hat{sub 0}<0.5 GeV{sup 2}/fm.

  18. Birds, traditional coffee plantations and spatial complexity: the diversity puzzle

    NARCIS (Netherlands)

    Leyequien Abarca, E.

    2006-01-01

    As the current accelerated and increasing loss of biological diversity have become apparent land managers and ecologists have sought to identify significant habitats to the preservation of biodiversity. A critical component of biodiversity protection is the understanding of the ecological forces sha

  19. Puzzling initial conditions in the R_h=ct model

    CERN Document Server

    Bengochea, Gabriel R

    2016-01-01

    In recent years, some studies have drawn attention to the lack of large-angle correlations in the observed cosmic microwave background (CMB) temperature anisotropies with respect to that predicted within the standard LCDM model. Lately, some authors have shown that such a lack of correlations could be explained in the framework of the so-called R_h=ct model without inflation. The aim of this work is to find a mechanism to generate, through a quantum field theory, the primordial power spectrum presented by these authors. Specifically, we consider two different scenarios: first, we assume a scalar field dominating the early universe in the R_h=ct cosmological model, and second, we deal with the possibility of adding an early inflationary phase to the mentioned model. We analyze the consistency between the predicted and observed amplitudes of the CMB temperature anisotropies in both scenarios. During this search, we run into deep issues which could indicate that it is not clear how to characterize the primordial...

  20. Patchwork plagiarism--a jigsaw of stolen puzzle pieces.

    Science.gov (United States)

    Supak Smolcić, Vesna; Bilić-Zulle, Lidija

    2013-01-01

    Plagiarism remains at the top in terms of interest to the scientific community. In its many vicious forms, patchwork plagiarism is characterized by numerous unresolved issues and often passes "below the radar" of editors and reviewers. The problem of detecting the complexity of misconduct has been partially resolved by plagiarism detection software. However, interpretation of relevant reports is not always obvious or easy. This article deals with plagiarism in general and patchwork plagiarism in particular, as well as related problems that editors must deal with to maintain the integrity of scientific journals.

  1. 从对索伯-威尔逊模型的批判入手浅析利他行为进化难题%Analysis the Puzzle of Evolution of Altruistic Behavior Beginning from the Critique of the Sober-Wilson Model

    Institute of Scientific and Technical Information of China (English)

    张涛

    2012-01-01

    According to the inclusive fitness theory, altruistic behavior can't be evolved because that altruistic behavior would reduce the fitness of the altruist. As there are many altruistic behaviors in the nature and human society, how can explain the evolution of altruistic behavior is a puzzle perplexed many biology philosophers include Darwin. Elliott Sober and David Sloan Wilson created a mathematical model to explain the evolution of altruistic behavior using group selection theory at 1998. But this model is failed because of its manipulation about the weight of two sets of data on the basis of Anti-Simpson's paradox. On the critique of Sober & Wilson model, we come up with a new model to explain the e- volution of altruistic behaviors. The altruistic behavior is evolved at both individual selection and group selection. A group which has altruists has superiority when the cost of the altruistic behavior can produce more benefits. This superiority would be maintained by defense mechanism altruists possessed. Thus, the altruistic behavior can be evolved.%根据内合适应理论,利他者的利他行为会降低利他者自身的适合度,利他行为因此不能得到进化,但在自然界和人类社会中利他行为却广泛存在着,故而如何解释利他行为的进化成为了自达尔文以来长期困扰着生物学哲学界的一个难题。1998年索伯和威尔逊建立了一套数学模型,以试图根据群体选择理论来解释利他行为的进化,但二人所展示的利他行为进化是根据反辛普森悖论对两组数据在权重上进行操作所得到的虚假真实。在对索伯一威尔逊模型批判的基础上,我们提出了一种利他行为进化模型,认为利他行为的进化是在个体选择和群体选择的共同作用下进行的,当利他者的付出会给群体带来更高的回报时,拥有利他者的群体会表现出进化优势,这种进化优势与利他者在群体中的比率成正相关

  2. 巴西技术设备和维修协会(Sobratema)在CONXEPO CON/AGG 2011期间举办新闻发布会

    Institute of Scientific and Technical Information of China (English)

    谷雨檀

    2011-01-01

    @@ 2011年3月22日,巴西技术设备和维修协会(Sobratema)举办新闻发布会,Sobratema副主席Mario Humberto Marques先生就Sobratema、巴西工程设备市场和M&T展会等情况做了报告.

  3. 基于 Cocos2d 引擎的 PuzzleGame 开发%Development of Puzzle Game Based on Cocos2d Engine

    Institute of Scientific and Technical Information of China (English)

    徐伟; 李颖; 李誉

    2015-01-01

    With the rapid updating of intelligent mobile phone replacement and wide spread ,the game has already turn to the mobile phone terminal from the PC Game ,Webpage Game .In view of Mobile Game ,this paper introduced an Android mobile phone game development process based on Cocos2d engine ,and simply introduces the main elements of the game ,the director , scene ,layer and sprite ,it also described the design and implement of game body ,and tested the game on the phone .So that it can help developers get a overall cognition on the Cocos2d game engine application frame ,finally the game is in operation on‐line .%随着智能手机的快速更新换代和广泛普及,游戏也从端游、页游开始转向手机端。针对手游端,文章给出了一个基于Cocos2d引擎的Android手机游戏的开发流程,简单介绍了导演、场景、布景、精灵等主要游戏元素,并阐述了游戏主体的设计与实现以及最后的真机测试,以便帮助开发人员对Cocos2d引擎游戏应用程序框架有一个整体的认知,使得游戏最终上线运行。

  4. On the Issue of Consume Puzzle and Puzzled Consume%消费的困惑与困惑的消费

    Institute of Scientific and Technical Information of China (English)

    李兰芬

    2001-01-01

    本文重点论述了消费的困惑与困惑的消费,论述了这双重困惑的种种表现,提出了合理设定、规范和选择人们的消费理念和消费模式是当前亟待解决的重要课题。

  5. Acute and Chronic Plasma Metabalomic and Liver Transcriptomic Stress Effects in a Mouse Model with Features of Post-Traumatic Stress Disorder

    Science.gov (United States)

    2015-01-28

    Cancer Research, Frederick, MD, United States of America, 4 NIH West Coast Metabolomics Center, University of California Davis, Davis, CA, United...in AggE mice at 24 hrs after the 5-day and 10-day stress regimens. In contrast, granulocyte chemotactic protein-2 (GCP-2) and macrophage -derived chemo...Ctrl mice, the gene set enrichment analysis indicated that the AggE livers were more inflamed than the Ctrl livers. Additionally, well known stress

  6. New floristic records in the Balkans: 7

    DEFF Research Database (Denmark)

    Tan, Kit; Sfikas, George; Vold, Gert

    2008-01-01

    ), Dipsacaceae (7), Elaeagnaceae (74), Euphorbiaceae (8), Fabaceae (9, 35-36, 67-71, 80-83, 89), Gentianaceae (37), Geraniaceae (38), Iridaceae (52, 53), Juncaceae (54), Lamiaceae (10, 39, 102, 103), Liliaceae s.l. (55, 56, 92), Linaceae (40), Malvaceae (90), Onagraceae (11), Orchidaceae (66, 79), Plumbaginaceae...

  7. New floristic records in the Balkans: 1

    DEFF Research Database (Denmark)

    2006-01-01

    ), Amaryllidaceae (38), Apiaceae (17, 18, 47, 80, 83, 84), Asclepiadaceae (85), Asteraceae (29, 31, 86-91), Brassicaceae (3, 48, 70), Campanulaceae (49, 71, 76), Cannabaceae (72), Caprifoliaceae (4), Caryophyllaceae (19, 20, 32, 33, 50-52), Chenopodiaceae (5), Cyperaceae (28, 78), Dipsacaceae (34, 53, 54), Fabaceae...

  8. The Oslo Museum Puzzle. Reflections on the relation between culture and economy

    Directory of Open Access Journals (Sweden)

    Joar Skrede

    2011-03-01

    Full Text Available The decision has been made to relocate several cultural institutions in Oslo, without any existing plans for the old premises. In this article, the supportive arguments are analysed against the backdrop of the critical voices. The critics want to preserve the old buildings because they are embedded in the nation’s collective memory and have value as history. The supporters of the plans argue that the new buildings are bricks in a bigger city renewal project and shall generate synergetic effects beyond just functioning as cultural institutions. Critical discourse analysis is used eclectically as a methodological framework with a specific focus on what structural patterns of social change the arguments imply. The conclusion is that economy’s entry into the cultural sphere may be a threat to the cultural heritage.

  9. Trypanosoma cruzi extracellular amastigotes and host cell signaling: more pieces to the puzzle

    Directory of Open Access Journals (Sweden)

    Éden Ramalho Ferreira

    2012-11-01

    Full Text Available Among the different infective stages that Trypanosoma cruzi employs to invade cells, extracellular amastigotes have recently gained attention by our group. This is true primarily because these amastigotes are able to infect cultured cells and animals, establishing a sustainable infective cycle. Extracellular amastigotes are thus an excellent means of adaptation and survival for T. cruzi, whose different infective stages each utilize unique mechanisms for attachment and penetration. Here we discuss some features of host cell invasion by extracellular amastigotes and the associated host cell signaling events that occur as part of the process.

  10. Fibromyalgia, infection and vaccination: two more parts in the etiological puzzle.

    Science.gov (United States)

    Ablin, Jacob N; Shoenfeld, Yehuda; Buskila, Dan

    2006-11-01

    As the pathogenesis of fibromyalgia continues to raise debate, multiple putative triggers have been implicated. The current review summarizes the available data linking fibromyalgia to either infection or vaccination. Multiple infectious agents have been associated with the development of either full-blown fibromyalgia (e.g. hepatits C), or with symptom complexes extensively overlapping with that syndrome (e.g. chronic Lyme disease). The cases of Lyme disease, mycoplasma, hepatits C and HIV are detailed. Despite the described associations, no evidence is available demonstrating the utility of antibiotic or anti-viral treatment in the management of fibromyalgia. Possible mechanistic links between fibromyalgia and HIV are reviewed. Associations have been described between various vaccinations and symptom complexes including fibromyalgia and chronic fatigue syndrome. The case of Gulf War syndrome, a functional multisystem entity sharing many clinical characteristics with fibromyalgia is discussed, with emphasis on the possibility of association with administration of multiple vaccinations during deployment in the Persian Gulf and the interaction with stress and trauma. Based on this example a model is proposed, wherein vaccinations function as co-triggers for the development of functional disorders including fibromyalgia, in conjunction with additional contributing factors.

  11. THE PUZZLING MUTUAL ORBIT OF THE BINARY TROJAN ASTEROID (624) HEKTOR

    Energy Technology Data Exchange (ETDEWEB)

    Marchis, F.; Cuk, M. [Carl Sagan Center at the SETI Institute, Mountain View, CA 94043 (United States); Durech, J. [Astronomical Institute, Faculty of Mathematics and Physics, Charles University, Prague (Czech Republic); Castillo-Rogez, J. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Vachier, F.; Berthier, J. [IMCCE-Obs de Paris, F-75014 Paris (France); Wong, M. H.; Kalas, P.; Duchene, G. [Department of Astronomy, University of California at Berkeley, Berkeley, CA 94720 (United States); Van Dam, M. A. [Flat Wavefronts, Christchurch 8140 (New Zealand); Hamanowa, H. [Hamanowa Observatory, Motomiya, Fukushima 969-1204 (Japan); Viikinkoski, M., E-mail: fmarchis@seti.org [Tampere University of Technology, FI-33101 Tampere (Finland)

    2014-03-10

    Asteroids with satellites are natural laboratories to constrain the formation and evolution of our solar system. The binary Trojan asteroid (624) Hektor is the only known Trojan asteroid to possess a small satellite. Based on W. M. Keck adaptive optics observations, we found a unique and stable orbital solution, which is uncommon in comparison to the orbits of other large multiple asteroid systems studied so far. From lightcurve observations recorded since 1957, we showed that because the large Req = 125 km primary may be made of two joint lobes, the moon could be ejecta of the low-velocity encounter, which formed the system. The inferred density of Hektor's system is comparable to the L5 Trojan doublet (617) Patroclus but due to their difference in physical properties and in reflectance spectra, both captured Trojan asteroids could have a different composition and origin.

  12. Student Engagement and Academic Performance in Mexico: Evidence and Puzzles from PISA

    Science.gov (United States)

    Weiss, Christopher C.; García, Emma

    2015-01-01

    This paper investigates the relationship between student engagement--with teachers and schools--and academic performance in Mexico. It uses hierarchical linear models and data from the OECD 2003 PISA study to examine the relative importance of engagement in comparison to other educational inputs--school and family characteristics--as predictors of…

  13. Metabolomics investigation to shed light on cheese as a possible piece in the French paradox puzzle

    DEFF Research Database (Denmark)

    Zheng, Hong; Yde, Christian C; Clausen, Morten R;

    2015-01-01

    and TMAO levels and increased fecal excretion of acetate, propionate and lipid. Compared with milk intake, cheese consumption significantly reduced urinary citrate, creatine and creatinine levels and significantly increased the microbial-related metabolites butyrate, hippurate and malonate. Correlation...

  14. Pieces to the puzzle of high-redshift galaxies falling into place

    DEFF Research Database (Denmark)

    Geier, Stefan Johannes

    mass models. Our findings indicate older ages for these galaxies than expected. Also, their remarkable compactness was corroborated. Further conclusions such as about the validity of the downsizing paradigm are not possible given the very small sample of just two such galaxies. Furthermore, we present...

  15. The Key to Sufficient Food Production; Big data analysis solves complicated puzzle

    NARCIS (Netherlands)

    Hall, R.D.; Finkers, H.J.; Wehrens, H.R.M.J.

    2015-01-01

    According to the FAO, crops will need to yield twice as much wih half the input for us to still be able to feed the rapidly growing world population in 2050. This goal is attainable if we make good use of available big data from the various omics approaches, say biologists, mathematicians and breede

  16. Puzzle and Innovation: Thoughts over New Countryside Planning in New Era

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    Based on the changes of background of current new countryside planning, this paper points out that the new countryside planning is faced with two problems: the obscure planning guiding ideology and the slow implementation process. Combined with the new countryside planning practices of the author, it states that the new countryside planning should be innovated from the aspects of planning guiding ideology, implementation institution, ways of expression, and so on.

  17. A resolution of the inclusive flavor-breaking sum rule $\\tau$ $V_{us}$ puzzle

    CERN Document Server

    Maltman, K; Lewis, R; Wolfe, C E; Zanotti, J

    2015-01-01

    A combination of continuum and lattice methods is used to investigate systematic issues in the finite-energy-sum-rule determination of $V_{us}$ based on flavor-breaking combinations of hadronic $\\tau$ decay data. Results for $V_{us}$ obtained using assumptions for $D>4$ OPE contributions employed in previous conventional implementations of this approach are shown to display significant unphysical dependences on the choice of sum rule weight, $w$, and upper limit, $s_0$, of the relevant experimental spectral integrals. Continuum and lattice results suggest the necessity of a new implementation of the flavor-breaking sum rule approach, in which not only $\\vert V_{us}\\vert$, but also $D>4$ effective condensates are fit to data. Lattice results also provide a means of quantifying the truncation error for the slowly converging $D=2$ OPE series. The new implementation is shown to produce $\\vert V_{us}\\vert$ results free of unphysical $s_0$- and $w$-dependences and typically $\\sim 0.0020$ higher than the (unstable) ...

  18. Outsourcing, Supplier Relations and Internationalisation: Global Sourcing Strategy as a Chinese puzzle

    NARCIS (Netherlands)

    M.J. Mol

    2001-01-01

    textabstractOndernemingen hebben vele doelen. Een belangrijk doel van ondernemingen is om voortdurend het bedrijfsresultaat te verbeteren. Het vakgebied strategisch management houdt zich bezig met de vraag welke methoden geschikt zijn om betere bedrijfsresultaten dan de concurrentie te behalen. Dit

  19. The 'gender puzzle' of alternative medicine and holistic spirituality: a literature review.

    Science.gov (United States)

    Keshet, Yael; Simchai, Dalit

    2014-07-01

    Both as producers and consumers women are more likely than men to engage with complementary and alternative medicine (CAM) and 'New Age' holistic spiritualities. We conducted a literature review of sociological and anthropological articles, with the aim of studying why women in particular use and practice these alternatives, and whether using them presents an opportunity to challenge the conventional gender order and unequal power relations. A systematic search of nine databases, complemented by an informal search resulted in the identification of 114 articles, of which 27 were included in the review. The search period was limited to 2000-2013. Thematic analysis of the literature indicated three major trends: women draw on traditional female resources and perceived 'feminine' characteristics; the realm of CAM and holistic spirituality challenges power relations and gender inequalities in healthcare, wellbeing, and employment, and may serve as an emancipating, empowering alternative; however, factors such as lack of political support, legitimacy, and a solid institutional base for the field of CAM and holistic spirituality, and its use by predominantly white middle- and upper-class women, work against significant change in the realm of healthcare and limit gendered social change. We suggest that the empowerment women experience is a form of feminine strength and personal empowerment that stems from power-from-within, which is not directed toward resistance. The literature review reveals some lacunae in the literature that call for future gendered research: the lack of quantitative studies, of data concerning the financial success of CAM practitioners, of studies linking CAM with a feminist-oriented analysis of the medical world, of understanding gender perceptions in the holistic milieu and CAM, and of studies conducted from an intersectionality perspective.

  20. Hyalinizing trabecular tumor of the thyroid gland: A puzzling entity on fine needle aspiration cytology

    Directory of Open Access Journals (Sweden)

    Jitendra Nasit

    2014-01-01

    Full Text Available Hyalinizing trabecular tumor (HTT is a rare unique but controversial thyroid neoplasm, characterized by prominent trabecular growth pattern and stromal hyalinization. Whether HTT is a benign tumor or a variant of papillary thyroid carcinoma (PTC is still unclear. Cytology findings of HTT have been described in few reports. Cytological features of HTT frequently overlap with those of PTC and medullary thyroid carcinoma, which can lead to frequent misdiagnosis. In order to avoid overtreatment like total thyroidectomy, pathologist should be aware of cytological features of HTT. We present a case of 35-year-old female with a right-side thyroid swelling for three years. Fine needle aspiration cytology was performed. According to The Bethesda System for Reporting Thyroid Cytopathology, cytological diagnosis of benign thyroid neoplasm was made. Histopathology of the right thyroidectomy specimen showed HTT. Accurate preoperative diagnosis of HTT requires a very meticulous and cautious approach in the evaluation of cytological features. Trabecular pattern of cells, vague curved nuclear palisading, radiating arrangement of cells around hyaline material, spindled to elongated cells, filamentous cytoplasmic processes with ill-defined cell border and yellow bodies are important diagnostic features of HTT. Nuclear features alone are insufficient for the diagnosis of HTT. Any suspicious cytology of thyroid lesion should follow hemithyroidectomy and histopathological evaluation.

  1. Solving the small-scale structure puzzles with dissipative dark matter

    CERN Document Server

    Foot, Robert

    2016-01-01

    Small-scale structure is studied in the context of dissipative dark matter, arising for instance in models with a hidden unbroken Abelian sector, so that dark matter couples to a massless dark photon. The dark sector interacts with ordinary matter via gravity and photon-dark photon kinetic mixing. Mirror dark matter is a theoretically constrained special case where all parameters are fixed except for the kinetic mixing strength, $\\epsilon$. In these models, the dark matter halo around spiral and irregular galaxies takes the form of a dissipative plasma which evolves in response to various heating and cooling processes. It has been argued previously that such dynamics can account for the inferred cored density profiles of galaxies and other related structural features. Here we focus on the apparent deficit of nearby small galaxies ("missing satellite problem"), which these dissipative models have the potential to address through small-scale power suppression by acoustic and diffusion damping. Using a variant o...

  2. The Puzzling Detection of X-rays From Pluto by Chandra

    CERN Document Server

    Lisse, C M; Wolk, S J; Bagenal, F; Stern, S A; Gladstone, G R; Cravens, T E; Hill, M E; Kollmann, P; Weaver, H A; Strobel, D F; Elliott, H A; McComas, D J; Binzel, R P; Snios, B T; Bhardwaj, A; Chutjian, A; Young, L A; Olkin, C B; Ennico, K A

    2016-01-01

    Using Chandra ACIS-S, we have obtained imaging Xray spectrophotometry of the Pluto system in support of the New Horizons flyby on 14 July 2015. 174 ksec of observations were obtained on 4 visits in Feb 2014 to Aug 2015. We measured a net signal of 6.8 counts and a noise level of 1.2 counts in a comoving 11 x 11 pixel box (100 x 100 R_Pluto) in the 0.31 to 0.60 keV passband for a detection at > 99.95 C.L. The Pluto photons do not match the background spectrum, are coincident with a 90% flux aperture comoving with Pluto, and are not sky source confused. The mean 0.31 to 0.60 keV Xray power from Pluto is 200 MW, in the midrange of Xray power levels seen for known solar system emission sources: auroral precipitation, solar Xray scattering, and charge exchange (CXE) between solar wind (SW) ions & atmospheric neutrals. We eliminate auroral effects as a source, as Pluto has no known magnetic field & the New Horizons Alice UV spectrometer detected no airglow from Pluto during the flyby. Nano-scale atmospheric...

  3. Flux Compactifications of Projective Spaces and The S-Duality Puzzle

    CERN Document Server

    Bouwknegt, P; Jurco, B; Mathai, V; Sati, H

    2005-01-01

    We derive a formula for D3-brane charge on a compact spacetime, which includes torsion corrections to the tadpole cancellation condition. We use this to classify D-branes and RR fluxes in type II string theory on RP^3xRP^{2k+1}xS^{6-2k} with torsion H-flux and to demonstrate the conjectured T-duality to S^3xS^{2k+1}xS^{6-2k} with no flux. When k=1, H\

  4. Jigsawing Education Evaluation. Pieces from the Italian New Public Management Puzzle

    Science.gov (United States)

    Grimaldi, Emiliano; Serpieri, Roberto

    2013-01-01

    This article deals with the "troubled history" of head teachers' evaluation in Italy, as a specific strand of the controversial and fuzzy embedding of New Public Management (NPM) discourse in the Italian education system. Since the 1990s, NPM has shaped both policy agendas and professionals' subjectivities, leading the way to a process…

  5. Malaysian primary care doctors' views on men's health: an unresolved jigsaw puzzle

    Directory of Open Access Journals (Sweden)

    Ismail Shaiful

    2011-05-01

    Full Text Available Abstract Background Men have been noted to utilise health care services less readily then women. Primary care settings provide an opportunity to engage men in health care activities because of close proximity to the target group (men in the community. Understanding attitudes towards men's health among Malaysian primary care doctors is important for the effective delivery of health services to men. We aimed to explore the opinions and attitudes of primary care doctors (PCDs relating to men's health and help-seeking behaviour. Methods A qualitative approach to explore the opinions of 52 PCDs was employed, using fourteen in-depth interviews and eight focus group discussions in public and private settings. Purposive sampling of PCDs was done to ensure maximum variation in the PCD sample. Interviews were recorded and transcribed verbatim for analysis. Open coding with thematic analysis was used to identify key issues raised in the interview. Results The understanding of the concept of men's health among PCDs was fragmented. Although many PCDs were already managing health conditions relevant and common to men, they were not viewed by PCDs as "men's health". Less attention was paid to men's help-seeking behaviour and their gender roles as a potential determinant of the poor health status of men. There were opposing views about whether men's health should focus on men's overall health or a more focused approach to sexual health. There was also disagreement about whether special attention was warranted for men's health services. Some doctors would prioritise more common conditions such as hypertension, diabetes and hypercholesterolaemia. Conclusions The concept of men's health was new to PCDs in Malaysia. There was wide variation in understanding and opposing attitudes towards men's health among primary care doctors. Creating awareness and having a systematic approach would facilitate PCDs in delivering health service to men.

  6. Sound-Symbolism: A Piece in the Puzzle of Word Learning

    Science.gov (United States)

    Parault, Susan J.; Schwanenflugel, Paula J.

    2006-01-01

    Sound-symbolism is the idea that the relationship between word sounds and word meaning is not arbitrary for all words, but rather that there are subsets of words in the world's languages for which sounds and their symbols have some degree of correspondence. The present research investigates sound-symbolism as a possible route to the learning of an…

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

    Science.gov (United States)

    Wright, Jason T.; Sigurdsson, 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.

  8. Self-similarity, conservation of entropy/bits and the black hole information puzzle

    Energy Technology Data Exchange (ETDEWEB)

    Singleton, Douglas [Department of Physics, California State University Fresno,2345 East San Ramon Avenue M/S MH37, Fresno, CA 93740-8031 (United States); Department of Physics, Institut Teknologi Bandung,Jalan Ganesha 10, Bandung 40132 (Indonesia); Vagenas, Elias C. [Theoretical Physics Group, Department of Physics, Kuwait University,P.O. Box 5969, Safat 13060 (Kuwait); Zhu, Tao [GCAP-CASPER, Physics Department, Baylor University,One Bear Place, # 97316, Waco, TX 76798-7316 (United States); Institute for Advanced Physics & Mathematics, Zhejiang University of Technology,18 Chao-Wang Rd, Hangzhou, 310032 (China)

    2014-05-19

    John Wheeler coined the phrase “it from bit” or “bit from it” in the 1980s. However, much of the interest in the connection between information, i.e. “bits”, and physical objects, i.e. “its”, stems from the discovery that black holes have characteristics of thermodynamic systems having entropies and temperatures. This insight led to the information loss problem — what happens to the “bits” when the black hole has evaporated away due to the energy loss from Hawking radiation? In this essay we speculate on a radical answer to this question using the assumption of self-similarity of quantum correction to the gravitational action and the requirement that the quantum corrected entropy be well behaved in the limit when the black hole mass goes to zero.

  9. Discovering the Puzzling Behaviour of Electrons with the Grimaldi-Young Experiment

    Science.gov (United States)

    Matteucci, Giorgio; Castaneda, Roman; Serna, Samuel; Medina, Francisco; Garcia-Sucerquia, Jorge

    2010-01-01

    An experiment analogous to that devised by Grimaldi and subsequently repeated by Young to study the nature of light has been realized with electrons. Following the Grimaldi and Young line of thought, an original approach is presented to introduce undergraduate physics students to the wave behaviour of electrons. An electron microscope equipped…

  10. Discovering the puzzling behaviour of electrons with the Grimaldi-Young experiment

    Energy Technology Data Exchange (ETDEWEB)

    Matteucci, Giorgio [Department of Physics, University of Bologna, and CNISM, V/le B. Pichat, 6/2, I 40127 Bologna (Italy); Castaneda, Roman; Serna, Samuel; Garcia-Sucerquia, Jorge [School of Physics, Universidad Nacional de Colombia Sede MedellIn, A.A. 3840, Medellin (Colombia); Medina, Francisco [Institute of Physics, Universidad de Antioquia, A.A. 1226, Medellin (Colombia)], E-mail: giorgio.matteucci@unibo.it

    2010-03-15

    An experiment analogous to that devised by Grimaldi and subsequently repeated by Young to study the nature of light has been realized with electrons. Following the Grimaldi and Young line of thought, an original approach is presented to introduce undergraduate physics students to the wave behaviour of electrons. An electron microscope equipped with a low coherent source of electrons and a thin platinum wire, acting as an opaque obstacle, is used to reproduce the experimental conditions adopted by Grimaldi and Young with light. Electron interference fringes produced in the geometrical shadow of the obstacle are interpreted by assuming that electrons behave like a sound or a light wave. This hypothesis is confirmed by the modelling of the experimental electron interference patterns.

  11. Analysing Policy in the Context(s) of Practice: A Theoretical Puzzle

    Science.gov (United States)

    Grimaldi, Emiliano

    2012-01-01

    This essay contributes to the construction of a critically informed toolbox of diverse concepts for education policy analysis. Focusing on the context(s) of practice of the policy cycle, the article outlines an interpretative framework to grasp policy enactment across different localities, the influences bearing upon those enactments as well as…

  12. Environmental history: a piece in the puzzle for establishing plans for environmental management.

    Science.gov (United States)

    Renberg, Ingemar; Bigler, Christian; Richard Bindler; Matilda Norberg; Johan Rydberg; Ulf Segerström

    2009-06-01

    Establishment of plans for environmental planning and management requires that a number of natural and societal factors must be taken into consideration. Insights into the inherent dynamics of nature as well as the role that past human activities have played for establishing the current condition of the landscape and the natural environment in general are essential. Many natural and man-made changes occur over time scales of decades or centuries, and these are difficult to comprehend without a historical perspective. Such a perspective can be obtained using palaeoecological studies, i.e. by geochemical and biological analyses of lake sediment and peat deposits. To illustrate the long-term dynamics of nature and particularly the role of man, we present here five case studies from Sweden concerning pollution, lake acidification, lake eutrophication, biodiversity, and landscape dynamics and conservation--topics of broad interests--and discuss benefits of including a longer time perspective in environmental management.

  13. The puzzle about the radial cut-off in galactic disks

    CERN Document Server

    Narayan, C A; Narayan, Chaitra A.; Jog, Chanda J.

    2003-01-01

    The stellar disk in a spiral galaxy is believed to be truncated physically because the disk surface brightness is observed to fall faster than that for an exponential in the outer, faint regions. We review the literature associated with this phenomenon and find that a number of recent observations contradict the truncation picture. Hence we question the very existence of a physical outer cut-off in stellar disks. We show, in this paper, that the observed drop in the surface brightness profiles in fact corresponds to a negligible decrease in intensity, and that this minor change at the faint end appears to be exaggerated on a log-normal plot. Since minor deviations from a perfect exponential are common throughout the disk, we suggest that such a deviation at the faint end could easily give rise to the observed sharp drop.

  14. Nanoparticle induced oxidative stress in cancer cells: adding new pieces to an incomplete jigsaw puzzle.

    Science.gov (United States)

    Nogueira, Daniele Rubert; Rolim, Clarice M Bueno; Farooqi, Ammad Ahmad

    2014-01-01

    Nanotechnology is an emerging field with many promising applications in drug delivery systems. Because of outstanding developments in this field, rapidly increasing research is directed to the development of nanocarriers that may enhance the availability of drugs to the target sites. Substantial fraction of information has been added into the existing scientific literature focusing on the fact that nanoparticles usually generate reactive oxygen species to a greater extent than micro-sized particles. It is worth mentioning that oxidative stress regulates an array of cell signaling cascades that resulted in cancer cell damage. Accumulating experimental evidence over the years has shown that wide-ranging biological mechanisms are triggered by these NPs in cultured cells due to the unique properties of engineered nanoparticles. In this review, we have attempted to provide an overview of the signaling cascades that are activated by oxidative stress in cancer cells in response to different kinds of nanomaterials, including quantum dots, metallic and polymeric nanoparticles.

  15. Alternative Indices of Performance: An Exploration of Eye Gaze Metrics in a Visual Puzzle Task

    Science.gov (United States)

    2014-07-01

    complimentary information about operator state. 15. SUBJECT TERMS Workload, Eye Tracking, Eye Movements , Nonlinear Dynamics 16. SECURITY CLASSIFICATION OF: 17...15 10. Image pair 1 (Mountain Lake, Left; Sunflowers , Right...human performance. For example, qualitative shifts in movement (e.g., from walking to running), can be measured by the variability patterns in the

  16. Nanoparticle puzzles and research opportunities that go beyond state of the art.

    Science.gov (United States)

    Jee, Ah-Young; Lou, Kai; Jang, Hyun-Sook; Nagamanasa, K Hima; Granick, Steve

    2016-01-01

    We present an overview of current progress and research challenges in the field of nanoparticle assembly, touching on the following topics: (1) historical perspective; (2) consideration of what is a nanoparticle; (3) contrast between nanoparticle self-assembly and top-down construction; (4) opportunities for nanoparticles with more intelligent sub-structures; (5) opportunities for nanoparticle systems cued to interact subtly in space and time. In this personal and subjective account, certain holy grails for nanoparticle science and technology are identified.

  17. Toward defining the anatomo-proteomic puzzle of the human brain: An integrative analysis.

    Science.gov (United States)

    Fernandez-Irigoyen, Joaquín; Labarga, Alberto; Zabaleta, Aintzane; de Morentin, Xabier Martínez; Perez-Valderrama, Estela; Zelaya, María Victoria; Santamaria, Enrique

    2015-10-01

    The human brain is exceedingly complex, constituted by billions of neurons and trillions of synaptic connections that, in turn, define ∼900 neuroanatomical subdivisions in the adult brain (Hawrylycz et al. An anatomically comprehensive atlas of the human brain transcriptome. Nature 2012, 489, 391-399). The human brain transcriptome has revealed specific regional transcriptional signatures that are regulated in a spatiotemporal manner, increasing the complexity of the structural and molecular organization of this organ (Kang et al. Spatio-temporal transcriptome of the human brain. Nature 2011, 478, 483-489). During the last decade, neuroproteomics has emerged as a powerful approach to profile neural proteomes using shotgun-based MS, providing complementary information about protein content and function at a global level. Here, we revise recent proteome profiling studies performed in human brain, with special emphasis on proteome mapping of anatomical macrostructures, specific subcellular compartments, and cerebrospinal fluid. Moreover, we have performed an integrative functional analysis of the protein compilation derived from these large-scale human brain proteomic studies in order to obtain a comprehensive view of human brain biology. Finally, we also discuss the potential contribution of our meta-analysis to the Chromosome-centric Human Proteome Project initiative.

  18. Puzzling γ-ray strength functions in 44,45Sc and 50,51V

    Science.gov (United States)

    Larsen, A. C.; Guttormsen, M.; Chankova, R.; Ingebretsen, F.; Lönnroth, T.; Messelt, S.; Rekstad, J.; Schiller, A.; Siem, S.; Syed, N. U. H.; Voinov, A.

    2008-05-01

    The nuclear physics group at the Oslo Cyclotron Laboratory (OCL) has developed a method to extract nuclear level density and γ-ray strength function simultaneously from primary γ-ray spectra. The resulting γ-ray strength functions of 44,45Sc and 50,51V show an unexpected, large enhancement at low γ-ray energies, indicating an increased probability of emitting low-energy γ rays in the quasi-continuum.

  19. The puzzle of the synthesis of the rare nuclide 138La

    Science.gov (United States)

    Goriely, S.; Arnould, M.; Borzov, I.; Rayet, M.

    2001-08-01

    The calculations of the p-process in the O/Ne layers of Type II supernovae are quite successful in reproducing the solar system content of p-nuclides. They predict, however, a significant underproduction of the rare odd-odd nuclide \\chem{138}{La}. A model for the explosion of a 25 Msun star with solar metallicity is used to suggest that nu_e -captures on \\chem{138}{Ba} may well be its most efficient production mechanism. The responsibility of an inadequate prediction of the \\chem{138}{La} and \\chem{139}{La} photodisintegration rates in the too low production of \\chem{138}{La} is also examined quantitatively. A detailed discussion of the theoretical uncertainties in these rates suggest that the required rate changes are probably too high to be fully plausible. Their measurement would be most welcome. They would help disentangling the relative contributions of thermonuclear and neutrino processes to the \\chem{138}{La} production.

  20. The puzzle of the synthesis of the rare nuclide 138La

    CERN Document Server

    Goriely, S; Borzov, I N; Rayet, M

    2001-01-01

    The calculations of the p-process in the O/Ne layers of Type II supernovae are quite successful in reproducung the solar system content of p-nuclides. They predict, however, a significant underproduction of the rare odd-odd nuclide 138La. A model for the explosion of a 25 Mo star with solar metallicity is used to suggest that electron neutrino captures on 138Ba may well be its most efficient production mechanism. The responsibility of an inadequate prediction of the 138La and 139La photodisintegration rates in the too low production of 138La is also examined quantitatively. A detailed discussion of the theoretical uncertainties in these rates suggest that the required rate changes are probably too high to be fully plausible. Their measurement would be most welcome. They would help disentangling the relative contributions of thermonuclear and neutrino processes to the 138La production.