Sample records for strogatz rewiring problem

  1. The Watts-Strogatz network model developed by including degree distribution: theory and computer simulation

    International Nuclear Information System (INIS)

    Chen, Y W; Zhang, L F; Huang, J P


    By using theoretical analysis and computer simulations, we develop the Watts-Strogatz network model by including degree distribution, in an attempt to improve the comparison between characteristic path lengths and clustering coefficients predicted by the original Watts-Strogatz network model and those of the real networks with the small-world property. Good agreement between the predictions of the theoretical analysis and those of the computer simulations has been shown. It is found that the developed Watts-Strogatz network model can fit the real small-world networks more satisfactorily. Some other interesting results are also reported by adjusting the parameters in a model degree-distribution function. The developed Watts-Strogatz network model is expected to help in the future analysis of various social problems as well as financial markets with the small-world property

  2. Dreams Rewired

    DEFF Research Database (Denmark)

    Thomsen, Bodil Marie Stavning; Luksch, Manu


    Bidraget kommenterer filmen Dreams Rewired og skaber refleksive spor i det vidt forgrenede film-arkiviske materiale om mere end et århundredes tele- og real-time kommunikation, hvor kropslig bevægelse bl.a gøres til data.......Bidraget kommenterer filmen Dreams Rewired og skaber refleksive spor i det vidt forgrenede film-arkiviske materiale om mere end et århundredes tele- og real-time kommunikation, hvor kropslig bevægelse bl.a gøres til data....

  3. Network rewiring dynamics with convergence towards a star network. (United States)

    Whigham, P A; Dick, G; Parry, M


    Network rewiring as a method for producing a range of structures was first introduced in 1998 by Watts & Strogatz ( Nature 393 , 440-442. (doi:10.1038/30918)). This approach allowed a transition from regular through small-world to a random network. The subsequent interest in scale-free networks motivated a number of methods for developing rewiring approaches that converged to scale-free networks. This paper presents a rewiring algorithm (RtoS) for undirected, non-degenerate, fixed size networks that transitions from regular, through small-world and scale-free to star-like networks. Applications of the approach to models for the spread of infectious disease and fixation time for a simple genetics model are used to demonstrate the efficacy and application of the approach.

  4. Can rewiring strategy control the epidemic spreading? (United States)

    Dong, Chao; Yin, Qiuju; Liu, Wenyang; Yan, Zhijun; Shi, Tianyu


    Relation existed in the social contact network can affect individuals' behaviors greatly. Considering the diversity of relation intimacy among network nodes, an epidemic propagation model is proposed by incorporating the link-breaking threshold, which is normally neglected in the rewiring strategy. The impact of rewiring strategy on the epidemic spreading in the weighted adaptive network is explored. The results show that the rewiring strategy cannot always control the epidemic prevalence, especially when the link-breaking threshold is low. Meanwhile, as well as strong links, weak links also play a significant role on epidemic spreading.

  5. Measuring the evolutionary rewiring of biological networks.

    Directory of Open Access Journals (Sweden)

    Chong Shou

    Full Text Available We have accumulated a large amount of biological network data and expect even more to come. Soon, we anticipate being able to compare many different biological networks as we commonly do for molecular sequences. It has long been believed that many of these networks change, or "rewire", at different rates. It is therefore important to develop a framework to quantify the differences between networks in a unified fashion. We developed such a formalism based on analogy to simple models of sequence evolution, and used it to conduct a systematic study of network rewiring on all the currently available biological networks. We found that, similar to sequences, biological networks show a decreased rate of change at large time divergences, because of saturation in potential substitutions. However, different types of biological networks consistently rewire at different rates. Using comparative genomics and proteomics data, we found a consistent ordering of the rewiring rates: transcription regulatory, phosphorylation regulatory, genetic interaction, miRNA regulatory, protein interaction, and metabolic pathway network, from fast to slow. This ordering was found in all comparisons we did of matched networks between organisms. To gain further intuition on network rewiring, we compared our observed rewirings with those obtained from simulation. We also investigated how readily our formalism could be mapped to other network contexts; in particular, we showed how it could be applied to analyze changes in a range of "commonplace" networks such as family trees, co-authorships and linux-kernel function dependencies.

  6. Review of The Joy of x: A Guided Tour of Math, from One to Infinity by Steven Strogatz

    Directory of Open Access Journals (Sweden)

    Michael T. Catalano


    Full Text Available Strogatz, Steven. The Joy of x: A Guided Tour of Math, from One to Infinity, (New York, NY, Houghton Mifflin Harcourt, 2012. 316 pp. ISBN 978-0-547-51765-0 The Joy of x: A Guided Tour of Math, from One to Infinity, by Steven Strogatz, is an engaging and example-filled argument for mathematics as a valuable and enjoyable activity. The thirty chapters are divided into six parts, entitled Numbers, Relationships, Shapes, Change, Data, and Frontiers. The discussion ranges from intuitive explanations of basic concepts such as place value, the four arithmetic operations, percentage increase and decrease, and solving equations, to “higher” levels of mathematics such as calculus, probability and statistics, group theory, and the nature of infinity. As in John Allen Paulos’ work, Beyond Numeracy, the chapters are short and punchy, and they can be read independently. While the book is not specifically devoted to numeracy, several chapters, especially those in Part Five on Data, address ideas and examples relevant to quantitative literacy.

  7. Rewiring the network. What helps an innovation to diffuse?

    International Nuclear Information System (INIS)

    Sznajd-Weron, Katarzyna; Szwabiński, Janusz; Weron, Rafał; Weron, Tomasz


    A fundamental question related to innovation diffusion is how the structure of the social network influences the process. Empirical evidence regarding real-world networks of influence is very limited. On the other hand, agent-based modeling literature reports different, and at times seemingly contradictory, results. In this paper we study innovation diffusion processes for a range of Watts–Strogatz networks in an attempt to shed more light on this problem. Using the so-called Sznajd model as the backbone of opinion dynamics, we find that the published results are in fact consistent and allow us to predict the role of network topology in various situations. In particular, the diffusion of innovation is easier on more regular graphs, i.e. with a higher clustering coefficient. Moreover, in the case of uncertainty—which is particularly high for innovations connected to public health programs or ecological campaigns—a more clustered network will help the diffusion. On the other hand, when social influence is less important (i.e. in the case of perfect information), a shorter path will help the innovation to spread in the society and—as a result—the diffusion will be easiest on a random graph. (paper)

  8. Effects of partial time delays on phase synchronization in Watts-Strogatz small-world neuronal networks. (United States)

    Sun, Xiaojuan; Perc, Matjaž; Kurths, Jürgen


    In this paper, we study effects of partial time delays on phase synchronization in Watts-Strogatz small-world neuronal networks. Our focus is on the impact of two parameters, namely the time delay τ and the probability of partial time delay p delay , whereby the latter determines the probability with which a connection between two neurons is delayed. Our research reveals that partial time delays significantly affect phase synchronization in this system. In particular, partial time delays can either enhance or decrease phase synchronization and induce synchronization transitions with changes in the mean firing rate of neurons, as well as induce switching between synchronized neurons with period-1 firing to synchronized neurons with period-2 firing. Moreover, in comparison to a neuronal network where all connections are delayed, we show that small partial time delay probabilities have especially different influences on phase synchronization of neuronal networks.

  9. Rewiring of neuronal networks during synaptic silencing. (United States)

    Wrosch, Jana Katharina; Einem, Vicky von; Breininger, Katharina; Dahlmanns, Marc; Maier, Andreas; Kornhuber, Johannes; Groemer, Teja Wolfgang


    Analyzing the connectivity of neuronal networks, based on functional brain imaging data, has yielded new insight into brain circuitry, bringing functional and effective networks into the focus of interest for understanding complex neurological and psychiatric disorders. However, the analysis of network changes, based on the activity of individual neurons, is hindered by the lack of suitable meaningful and reproducible methodologies. Here, we used calcium imaging, statistical spike time analysis and a powerful classification model to reconstruct effective networks of primary rat hippocampal neurons in vitro. This method enables the calculation of network parameters, such as propagation probability, path length, and clustering behavior through the measurement of synaptic activity at the single-cell level, thus providing a fuller understanding of how changes at single synapses translate to an entire population of neurons. We demonstrate that our methodology can detect the known effects of drug-induced neuronal inactivity and can be used to investigate the extensive rewiring processes affecting population-wide connectivity patterns after periods of induced neuronal inactivity.

  10. Krebs cycle rewired for macrophage and dendritic cell effector functions. (United States)

    Ryan, Dylan Gerard; O'Neill, Luke A J


    The Krebs cycle is an amphibolic pathway operating in the mitochondrial matrix of all eukaryotic organisms. In response to proinflammatory stimuli, macrophages and dendritic cells undergo profound metabolic remodelling to support the biosynthetic and bioenergetic requirements of the cell. Recently, it has been discovered that this metabolic shift also involves the rewiring of the Krebs cycle to regulate cellular metabolic flux and the accumulation of Krebs cycle intermediates, notably, citrate, succinate and fumarate. Interestingly, a new role for Krebs cycle intermediates as signalling molecules and immunomodulators that dictate the inflammatory response has begun to emerge. This review will discuss the latest developments in Krebs cycle rewiring and immune cell effector functions, with a particular focus on the regulation of cytokine production. © 2017 Federation of European Biochemical Societies.

  11. 'Syncing' Up with the Quinn-Rand-Strogatz Constant: Hurwitz-ZetaFunctions in Non-Linear physics

    Energy Technology Data Exchange (ETDEWEB)

    Durgin, Natalie J.; Garcia, Sofia M.; Flournoy, Tamara; Bailey,David H.


    This work extends the analytical and computationalinvestigation of the Quinn-Rand-Strogatz (QRS) constants from non-linearphysics. The QRS constants (c1, c2, ..., cN) are found in a Winfreeoscillator mean-field system used to examine the transition of coupledoscillators as they lose synchronization. The constants are part of anasymptotic expansion of a function related to the oscillatorsynchronization. Previous work used high-precision software packages toevaluate c1 to 42 decimal-digits, which made it possible to recognize andprove that c1 was the root of a certain Hurwitz-zeta function. Thisallowed a value of c2 to beconjectured in terms of c1. Therefore thereis interest in determining the exact values of these constants to highprecision in the hope that general relationships can be establishedbetween the constants and the zeta functions. Here, we compute the valuesof the higher order constants (c3, c4) to more than 42-digit precision byextending an algorithm developed by D.H. Bailey, J.M. Borwein and R.E.Crandall. Several methods for speeding up the computation are exploredand an alternate proof that c1 is the root of a Hurwitz-zeta function isattempted.

  12. Rewiring protein synthesis: From natural to synthetic amino acids. (United States)

    Fan, Yongqiang; Evans, Christopher R; Ling, Jiqiang


    The protein synthesis machinery uses 22 natural amino acids as building blocks that faithfully decode the genetic information. Such fidelity is controlled at multiple steps and can be compromised in nature and in the laboratory to rewire protein synthesis with natural and synthetic amino acids. This review summarizes the major quality control mechanisms during protein synthesis, including aminoacyl-tRNA synthetases, elongation factors, and the ribosome. We will discuss evolution and engineering of such components that allow incorporation of natural and synthetic amino acids at positions that deviate from the standard genetic code. The protein synthesis machinery is highly selective, yet not fixed, for the correct amino acids that match the mRNA codons. Ambiguous translation of a codon with multiple amino acids or complete reassignment of a codon with a synthetic amino acid diversifies the proteome. Expanding the genetic code with synthetic amino acids through rewiring protein synthesis has broad applications in synthetic biology and chemical biology. Biochemical, structural, and genetic studies of the translational quality control mechanisms are not only crucial to understand the physiological role of translational fidelity and evolution of the genetic code, but also enable us to better design biological parts to expand the proteomes of synthetic organisms. This article is part of a Special Issue entitled "Biochemistry of Synthetic Biology - Recent Developments" Guest Editor: Dr. Ilka Heinemann and Dr. Patrick O'Donoghue. Copyright © 2017 Elsevier B.V. All rights reserved.

  13. Rewiring food systems to enhance human health and biosphere stewardship (United States)

    Gordon, Line J.; Bignet, Victoria; Crona, Beatrice; Henriksson, Patrik J. G.; Van Holt, Tracy; Jonell, Malin; Lindahl, Therese; Troell, Max; Barthel, Stephan; Deutsch, Lisa; Folke, Carl; Jamila Haider, L.; Rockström, Johan; Queiroz, Cibele


    Food lies at the heart of both health and sustainability challenges. We use a social-ecological framework to illustrate how major changes to the volume, nutrition and safety of food systems between 1961 and today impact health and sustainability. These changes have almost halved undernutrition while doubling the proportion who are overweight. They have also resulted in reduced resilience of the biosphere, pushing four out of six analysed planetary boundaries across the safe operating space of the biosphere. Our analysis further illustrates that consumers and producers have become more distant from one another, with substantial power consolidated within a small group of key actors. Solutions include a shift from a volume-focused production system to focus on quality, nutrition, resource use efficiency, and reduced antimicrobial use. To achieve this, we need to rewire food systems in ways that enhance transparency between producers and consumers, mobilize key actors to become biosphere stewards, and re-connect people to the biosphere.

  14. Domestication rewired gene expression and nucleotide diversity patterns in tomato. (United States)

    Sauvage, Christopher; Rau, Andrea; Aichholz, Charlotte; Chadoeuf, Joël; Sarah, Gautier; Ruiz, Manuel; Santoni, Sylvain; Causse, Mathilde; David, Jacques; Glémin, Sylvain


    Plant domestication has led to considerable phenotypic modifications from wild species to modern varieties. However, although changes in key traits have been well documented, less is known about the underlying molecular mechanisms, such as the reduction of molecular diversity or global gene co-expression patterns. In this study, we used a combination of gene expression and population genetics in wild and crop tomato to decipher the footprints of domestication. We found a set of 1729 differentially expressed genes (DEG) between the two genetic groups, belonging to 17 clusters of co-expressed DEG, suggesting that domestication affected not only individual genes but also regulatory networks. Five co-expression clusters were enriched in functional terms involving carbohydrate metabolism or epigenetic regulation of gene expression. We detected differences in nucleotide diversity between the crop and wild groups specific to DEG. Our study provides an extensive profiling of the rewiring of gene co-expression induced by the domestication syndrome in one of the main crop species. © 2017 The Authors The Plant Journal © 2017 John Wiley & Sons Ltd.

  15. Network evolution: rewiring and signatures of conservation in signaling.

    Directory of Open Access Journals (Sweden)

    Mark G F Sun

    Full Text Available The analysis of network evolution has been hampered by limited availability of protein interaction data for different organisms. In this study, we investigate evolutionary mechanisms in Src Homology 3 (SH3 domain and kinase interaction networks using high-resolution specificity profiles. We constructed and examined networks for 23 fungal species ranging from Saccharomyces cerevisiae to Schizosaccharomyces pombe. We quantify rates of different rewiring mechanisms and show that interaction change through binding site evolution is faster than through gene gain or loss. We found that SH3 interactions evolve swiftly, at rates similar to those found in phosphoregulation evolution. Importantly, we show that interaction changes are sufficiently rapid to exhibit saturation phenomena at the observed timescales. Finally, focusing on the SH3 interaction network, we observe extensive clustering of binding sites on target proteins by SH3 domains and a strong correlation between the number of domains that bind a target protein (target in-degree and interaction conservation. The relationship between in-degree and interaction conservation is driven by two different effects, namely the number of clusters that correspond to interaction interfaces and the number of domains that bind to each cluster leads to sequence specific conservation, which in turn results in interaction conservation. In summary, we uncover several network evolution mechanisms likely to generalize across peptide recognition modules.

  16. Modelling microbial metabolic rewiring during growth in a complex medium. (United States)

    Fondi, Marco; Bosi, Emanuele; Presta, Luana; Natoli, Diletta; Fani, Renato


    choosing among alternative objective functions on the resulting predictions of fluxes distribution. Here we provide a time-resolved, systems-level scheme of PhTAC125 metabolic re-wiring as a consequence of carbon source switching in a nutritionally complex medium. Our analyses suggest the presence of a potential efficient metabolic reprogramming machinery to continuously and promptly adapt to this nutritionally changing environment, consistent with adaptation to fast growth in a fairly, but probably inconstant and highly competitive, environment. Also, we show i) how functional partnership and co-regulation features can be predicted by integrating multi-step constraint-based metabolic modelling with fed-batch growth data and ii) that performing simulations under a sub-optimal objective function may lead to different flux distributions in respect to canonical FBA.

  17. Inverse relationship between adult hippocampal cell proliferation and synaptic rewiring in the dentate gyrus

    NARCIS (Netherlands)

    Butz, M.; Teuchert-Noodt, G; Grafen, K; van Ooyen, A.


    Adult neurogenesis is a key feature of the hippocampal dentate gyrus (DG). Neurogenesis is accompanied by synaptogenesis as new cells become integrated into the circuitry of the hippocampus. However, little is known to what extent the embedding of new neurons rewires the pre-existing network. Here

  18. TCA cycle rewiring fosters metabolic adaptation to oxygen restriction in skeletal muscle from rodents and humans. (United States)

    Capitanio, Daniele; Fania, Chiara; Torretta, Enrica; Viganò, Agnese; Moriggi, Manuela; Bravatà, Valentina; Caretti, Anna; Levett, Denny Z H; Grocott, Michael P W; Samaja, Michele; Cerretelli, Paolo; Gelfi, Cecilia


    In mammals, hypoxic stress management is under the control of the Hypoxia Inducible Factors, whose activity depends on the stabilization of their labile α subunit. In particular, the skeletal muscle appears to be able to react to changes in substrates and O 2 delivery by tuning its metabolism. The present study provides a comprehensive overview of skeletal muscle metabolic adaptation to hypoxia in mice and in human subjects exposed for 7/9 and 19 days to high altitude levels. The investigation was carried out combining proteomics, qRT-PCR mRNA transcripts analysis, and enzyme activities assessment in rodents, and protein detection by antigen antibody reactions in humans and rodents. Results indicate that the skeletal muscle react to a decreased O 2 delivery by rewiring the TCA cycle. The first TCA rewiring occurs in mice in 2-day hypoxia and is mediated by cytosolic malate whereas in 10-day hypoxia the rewiring is mediated by Idh1 and Fasn, supported by glutamine and HIF-2α increments. The combination of these specific anaplerotic steps can support energy demand despite HIFs degradation. These results were confirmed in human subjects, demonstrating that the TCA double rewiring represents an essential factor for the maintenance of muscle homeostasis during adaptation to hypoxia.

  19. Search for the non-canonical Ising spin glass on rewired square lattices (United States)

    Surungan, Tasrief


    A spin glass (SG) of non-canonical type is a purely antiferromagnetic (AF) system, exemplified by the AF Ising model on a scale free network (SFN), studied by Bartolozzi et al. [ Phys. Rev. B73, 224419 (2006)]. Frustration in this new type of SG is rendered by topological factor and its randomness is caused by random connectivity. As an SFN corresponds to a large dimensional lattice, finding non-canonical SG in lattice with physical dimension is desireable. However, a regular lattice can not have random connectivity. In order to obtain lattices with random connection and preserving the notion of finite dimension, we costructed rewired lattices. We added some extra bonds randomly connecting each site of a regular lattice to its next-nearest neighbors. Very recently, Surungan et al., studied AF Heisenberg system on rewired square lattice and found no SG behavior [AIP Conf. Proc. 1719, 030006 (2016)]. Due to the importance of discrete symmetry for phase transition, here we study similar structure for the Ising model (Z 2 symmetry). We used Monte Carlo simulation with Replica Exchange algorithm. Two types of structures were studied, firstly, the rewired square lattices with one extra bonds added to each site, and secondly, two bonds added to each site. We calculated the Edwards-Anderson paremeter, the commonly used parameter in searching for SG phase. The non-canonical SG is clearly observed in the rewired square lattice with two extra bonds added.

  20. Effects of rewiring strategies on information spreading in complex dynamic networks (United States)

    Ally, Abdulla F.; Zhang, Ning


    Recent advances in networks and communication services have attracted much interest to understand information spreading in social networks. Consequently, numerous studies have been devoted to provide effective and accurate models for mimicking information spreading. However, knowledge on how to spread information faster and more widely remains a contentious issue. Yet, most existing works are based on static networks which limit the reality of dynamism of entities that participate in information spreading. Using the SIR epidemic model, this study explores and compares effects of two rewiring models (Fermi-Dirac and Linear functions) on information spreading in scale free and small world networks. Our results show that for all the rewiring strategies, the spreading influence replenishes with time but stabilizes in a steady state at later time-steps. This means that information spreading takes-off during the initial spreading steps, after which the spreading prevalence settles toward its equilibrium, with majority of the population having recovered and thus, no longer affecting the spreading. Meanwhile, rewiring strategy based on Fermi-Dirac distribution function in one way or another impedes the spreading process, however, the structure of the networks mimic the spreading, even with a low spreading rate. The worst case can be when the spreading rate is extremely small. The results emphasize that despite a big role of such networks in mimicking the spreading, the role of the parameters cannot be simply ignored. Apparently, the probability of giant degree neighbors being informed grows much faster with the rewiring strategy of linear function compared to that of Fermi-Dirac distribution function. Clearly, rewiring model based on linear function generates the fastest spreading across the networks. Therefore, if we are interested in speeding up the spreading process in stochastic modeling, linear function may play a pivotal role.

  1. The impact of proximal cell rewiring compared with distal cell rewiring with single-stent deployment and subsequent kissing balloon inflation in the inadequate jailing of a Kaname stent on the side branch ostium. (United States)

    Nakao, Fumiaki


    To identify differences between proximal and distal cell rewiring with subsequent kissing balloon inflation (KBI) in the presence of a link connected to a carina on the jailed side branch ostium (SBO). Kaname stents were deployed in bifurcation models (n = 12) with subsequent KBI and were confirmed by optical coherence tomography. The jailing configuration and cell rewiring were completely controlled and classified as follows: FC-Dist, free carina (no links connected to a carina) and distal cell rewiring; CC-Prox, connected to a carina (the presence of a link connected to a central carina) and proximal cell rewiring; CC-Dist, connected to a carina and distal cell rewiring; and FarDist, far-distal cell rewiring. The number of frames with malapposed struts (MS) in the SBO was significantly smaller in the CC-Prox group than in the CC-Dist group (26.7 ± 1.5 and 39.7 ± 0.6, respectively, p < 0.05). The number of frames with MS continuously present from the distal end to the proximal side of the SBO was significantly smaller in the CC-Prox group than in the CC-Dist group (17.0 ± 2.0 and 36.7 ± 5.8, respectively, p < 0.05). The ratio of the maximal opened stent cell area to the SBO area was significantly larger in the CC-Prox group than in the CC-Dist group (64.2 ± 1.2% and 38.8 ± 5.6%, respectively, p < 0.05). This study showed that in cases with a link connected to a carina, fewer malapposed struts may be present in proximal cell rewiring with subsequent KBI than in distal cell rewiring.

  2. A rewired green fluorescent protein: folding and function in a nonsequential, noncircular GFP permutant. (United States)

    Reeder, Philippa J; Huang, Yao-Ming; Dordick, Jonathan S; Bystroff, Christopher


    The sequential order of secondary structural elements in proteins affects the folding and activity to an unknown extent. To test the dependence on sequential connectivity, we reconnected secondary structural elements by their solvent-exposed ends, permuting their sequential order, called "rewiring". This new protein design strategy changes the topology of the backbone without changing the core side chain packing arrangement. While circular and noncircular permutations have been observed in protein structures that are not related by sequence homology, to date no one has attempted to rationally design and construct a protein with a sequence that is noncircularly permuted while conserving three-dimensional structure. Herein, we show that green fluorescent protein can be rewired, still functionally fold, and exhibit wild-type fluorescence excitation and emission spectra.

  3. Cellular Plasticity Enables Adaptation to Unforeseen Cell-Cycle Rewiring Challenges (United States)

    Katzir, Yair; Stolovicki, Elad; Stern, Shay; Braun, Erez


    The fundamental dynamics of the cell cycle, underlying cell growth and reproduction, were previously found to be robust under a wide range of environmental and internal perturbations. This property was commonly attributed to its network structure, which enables the coordinated interactions among hundreds of proteins. Despite significant advances in deciphering the components and autonomous interactions of this network, understanding the interfaces of the cell cycle with other major cellular processes is still lacking. To gain insight into these interfaces, we used the process of genome-rewiring in yeast by placing an essential metabolic gene HIS3 from the histidine biosynthesis pathway, under the exclusive regulation of different cell-cycle promoters. In a medium lacking histidine and under partial inhibition of the HIS3p, the rewired cells encountered an unforeseen multitasking challenge; the cell-cycle regulatory genes were required to regulate the essential histidine-pathway gene in concert with the other metabolic demands, while simultaneously driving the cell cycle through its proper temporal phases. We show here that chemostat cell populations with rewired cell-cycle promoters adapted within a short time to accommodate the inhibition of HIS3p and stabilized a new phenotypic state. Furthermore, a significant fraction of the population was able to adapt and grow into mature colonies on plates under such inhibiting conditions. The adapted state was shown to be stably inherited across generations. These adaptation dynamics were accompanied by a non-specific and irreproducible genome-wide transcriptional response. Adaptation of the cell-cycle attests to its multitasking capabilities and flexible interface with cellular metabolic processes and requirements. Similar adaptation features were found in our previous work when rewiring HIS3 to the GAL system and switching cells from galactose to glucose. Thus, at the basis of cellular plasticity is the emergence of a yet

  4. Metabolic pathway rewiring in engineered cyanobacteria for solar-to-chemical and solar-to-fuel production from CO2. (United States)

    Woo, Han Min


    Photoautotrophic cyanobacteria have been developed to convert CO 2 to valuable chemicals and fuels as solar-to-chemical (S2C) and solar-to-fuel (S2F) platforms. Here, I describe the rewiring of the metabolic pathways in cyanobacteria to better understand the endogenous carbon flux and to enhance the yield of heterologous products. The plasticity of the cyanobacterial metabolism has been proposed to be advantageous for the development of S2C and S2F processes. The rewiring of the sugar catabolism and of the phosphoketolase pathway in the central cyanobacterial metabolism allowed for an enhancement in the level of target products by redirecting the carbon fluxes. Thus, metabolic pathway rewiring can promote the development of more efficient cyanobacterial cell factories for the generation of feasible S2C and S2F platforms.

  5. Topological, functional, and dynamic properties of the protein interaction networks rewired by benzo(a)pyrene

    Energy Technology Data Exchange (ETDEWEB)

    Ba, Qian [Key Laboratory of Food Safety Research, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai (China); Key Laboratory of Food Safety Risk Assessment, Ministry of Health, Beijing (China); Li, Junyang; Huang, Chao [Key Laboratory of Food Safety Research, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai (China); Li, Jingquan; Chu, Ruiai [Key Laboratory of Food Safety Research, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai (China); Key Laboratory of Food Safety Risk Assessment, Ministry of Health, Beijing (China); Wu, Yongning, E-mail: [Key Laboratory of Food Safety Risk Assessment, Ministry of Health, Beijing (China); Wang, Hui, E-mail: [Key Laboratory of Food Safety Research, Institute for Nutritional Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai (China); Key Laboratory of Food Safety Risk Assessment, Ministry of Health, Beijing (China); School of Life Science and Technology, ShanghaiTech University, Shanghai (China)


    Benzo(a)pyrene is a common environmental and foodborne pollutant that has been identified as a human carcinogen. Although the carcinogenicity of benzo(a)pyrene has been extensively reported, its precise molecular mechanisms and the influence on system-level protein networks are not well understood. To investigate the system-level influence of benzo(a)pyrene on protein interactions and regulatory networks, a benzo(a)pyrene-rewired protein interaction network was constructed based on 769 key proteins derived from more than 500 literature reports. The protein interaction network rewired by benzo(a)pyrene was a scale-free, highly-connected biological system. Ten modules were identified, and 25 signaling pathways were enriched, most of which belong to the human diseases category, especially cancer and infectious disease. In addition, two lung-specific and two liver-specific pathways were identified. Three pathways were specific in short and medium-term networks (< 48 h), and five pathways were enriched only in the medium-term network (6 h–48 h). Finally, the expression of linker genes in the network was validated by Western blotting. These findings establish the overall, tissue- and time-specific benzo(a)pyrene-rewired protein interaction networks and provide insights into the biological effects and molecular mechanisms of action of benzo(a)pyrene. - Highlights: • Benzo(a)pyrene induced scale-free, highly-connected protein interaction networks. • 25 signaling pathways were enriched through modular analysis. • Tissue- and time-specific pathways were identified.

  6. Modular pathway rewiring of Saccharomyces cerevisiae enables high-level production of L-ornithine

    DEFF Research Database (Denmark)

    Qin, Jiufu; Zhou, Yongjin J.; Krivoruchko, Anastasia


    Baker's yeast Saccharomyces cerevisiae is an attractive cell factory for production of chemicals and biofuels. Many different products have been produced in this cell factory by reconstruction of heterologous biosynthetic pathways; however, endogenous metabolism by itself involves many metabolites...... metabolite for a range of different natural products. The MPR strategy involves rewiring of the urea cycle, subcellular trafficking engineering and pathway re-localization, and improving precursor supply either through attenuation of the Crabtree effect or through the use of controlled fed...... the potential to use yeast more extensively for low-cost production of many high-value amino-acid-derived chemicals....

  7. Metabolic re-wiring of isogenic breast epithelial cell lines following epithelial to mesenchymal transition. (United States)

    Halldorsson, Skarphedinn; Rohatgi, Neha; Magnusdottir, Manuela; Choudhary, Kumari Sonal; Gudjonsson, Thorarinn; Knutsen, Erik; Barkovskaya, Anna; Hilmarsdottir, Bylgja; Perander, Maria; Mælandsmo, Gunhild M; Gudmundsson, Steinn; Rolfsson, Óttar


    Epithelial to mesenchymal transition (EMT) has implications in tumor progression and metastasis. Metabolic alterations have been described in cancer development but studies focused on the metabolic re-wiring that takes place during EMT are still limited. We performed metabolomics profiling of a breast epithelial cell line and its EMT derived mesenchymal phenotype to create genome-scale metabolic models descriptive of both cell lines. Glycolysis and OXPHOS were higher in the epithelial phenotype while amino acid anaplerosis and fatty acid oxidation fueled the mesenchymal phenotype. Through comparative bioinformatics analysis, PPAR-γ1, PPAR- γ2 and AP-1 were found to be the most influential transcription factors associated with metabolic re-wiring. In silico gene essentiality analysis predicts that the LAT1 neutral amino acid transporter is essential for mesenchymal cell survival. Our results define metabolic traits that distinguish an EMT derived mesenchymal cell line from its epithelial progenitor and may have implications in cancer progression and metastasis. Furthermore, the tools presented here can aid in identifying critical metabolic nodes that may serve as therapeutic targets aiming to prevent EMT and inhibit metastatic dissemination. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  8. Rewiring of embryonic glucose metabolism via suppression of PFK-1 and aldolase during mouse chorioallantoic branching. (United States)

    Miyazawa, Hidenobu; Yamaguchi, Yoshifumi; Sugiura, Yuki; Honda, Kurara; Kondo, Koki; Matsuda, Fumio; Yamamoto, Takehiro; Suematsu, Makoto; Miura, Masayuki


    Adapting the energy metabolism state to changing bioenergetic demands is essential for mammalian development accompanying massive cell proliferation and cell differentiation. However, it remains unclear how developing embryos meet the changing bioenergetic demands during the chorioallantoic branching (CB) stage, when the maternal-fetal exchange of gases and nutrients is promoted. In this study, using metabolome analysis with mass-labeled glucose, we found that developing embryos redirected glucose carbon flow into the pentose phosphate pathway via suppression of the key glycolytic enzymes PFK-1 and aldolase during CB. Concomitantly, embryos exhibited an increase in lactate pool size and in the fractional contribution of glycolysis to lactate biosynthesis. Imaging mass spectrometry visualized lactate-rich tissues, such as the dorsal or posterior neural tube, somites and head mesenchyme. Furthermore, we found that the heterochronic gene Lin28a could act as a regulator of the metabolic changes observed during CB. Perturbation of glucose metabolism rewiring by suppressing Lin28a downregulation resulted in perinatal lethality. Thus, our work demonstrates that developing embryos rewire glucose metabolism following CB for normal development. © 2017. Published by The Company of Biologists Ltd.

  9. Metabolic network rewiring of propionate flux compensates vitamin B12 deficiency in C. elegans (United States)

    Watson, Emma; Olin-Sandoval, Viridiana; Hoy, Michael J; Li, Chi-Hua; Louisse, Timo; Yao, Victoria; Mori, Akihiro; Holdorf, Amy D; Troyanskaya, Olga G; Ralser, Markus; Walhout, Albertha JM


    Metabolic network rewiring is the rerouting of metabolism through the use of alternate enzymes to adjust pathway flux and accomplish specific anabolic or catabolic objectives. Here, we report the first characterization of two parallel pathways for the breakdown of the short chain fatty acid propionate in Caenorhabditis elegans. Using genetic interaction mapping, gene co-expression analysis, pathway intermediate quantification and carbon tracing, we uncover a vitamin B12-independent propionate breakdown shunt that is transcriptionally activated on vitamin B12 deficient diets, or under genetic conditions mimicking the human diseases propionic- and methylmalonic acidemia, in which the canonical B12-dependent propionate breakdown pathway is blocked. Our study presents the first example of transcriptional vitamin-directed metabolic network rewiring to promote survival under vitamin deficiency. The ability to reroute propionate breakdown according to B12 availability may provide C. elegans with metabolic plasticity and thus a selective advantage on different diets in the wild. DOI: PMID:27383050

  10. Rewiring monocyte glucose metabolism via C-type lectin signaling protects against disseminated candidiasis. (United States)

    Domínguez-Andrés, Jorge; Arts, Rob J W; Ter Horst, Rob; Gresnigt, Mark S; Smeekens, Sanne P; Ratter, Jacqueline M; Lachmandas, Ekta; Boutens, Lily; van de Veerdonk, Frank L; Joosten, Leo A B; Notebaart, Richard A; Ardavín, Carlos; Netea, Mihai G


    Monocytes are innate immune cells that play a pivotal role in antifungal immunity, but little is known regarding the cellular metabolic events that regulate their function during infection. Using complementary transcriptomic and immunological studies in human primary monocytes, we show that activation of monocytes by Candida albicans yeast and hyphae was accompanied by metabolic rewiring induced through C-type lectin-signaling pathways. We describe that the innate immune responses against Candida yeast are energy-demanding processes that lead to the mobilization of intracellular metabolite pools and require induction of glucose metabolism, oxidative phosphorylation and glutaminolysis, while responses to hyphae primarily rely on glycolysis. Experimental models of systemic candidiasis models validated a central role for glucose metabolism in anti-Candida immunity, as the impairment of glycolysis led to increased susceptibility in mice. Collectively, these data highlight the importance of understanding the complex network of metabolic responses triggered during infections, and unveil new potential targets for therapeutic approaches against fungal diseases.

  11. Transcription activator-like effector hybrids for conditional control and rewiring of chromosomal transgene expression. (United States)

    Li, Yi; Moore, Richard; Guinn, Michael; Bleris, Leonidas


    The ability to conditionally rewire pathways in human cells holds great therapeutic potential. Transcription activator-like effectors (TALEs) are a class of naturally occurring specific DNA binding proteins that can be used to introduce targeted genome modifications or control gene expression. Here we present TALE hybrids engineered to respond to endogenous signals and capable of controlling transgenes by applying a predetermined and tunable action at the single-cell level. Specifically, we first demonstrate that combinations of TALEs can be used to modulate the expression of stably integrated genes in kidney cells. We then introduce a general purpose two-hybrid approach that can be customized to regulate the function of any TALE either using effector molecules or a heterodimerization reaction. Finally, we demonstrate the successful interface of TALEs to specific endogenous signals, namely hypoxia signaling and microRNAs, essentially closing the loop between cellular information and chromosomal transgene expression.

  12. Kinome-wide Decoding of Network-Attacking Mutations Rewiring Cancer Signaling

    DEFF Research Database (Denmark)

    Creixell, Pau; Schoof, Erwin M; Simpson, Craig D.


    Cancer cells acquire pathological phenotypes through accumulation of mutations that perturb signaling networks. However, global analysis of these events is currently limited. Here, we identify six types of network-attacking mutations (NAMs), including changes in kinase and SH2 modulation, network...... rewiring, and the genesis and extinction of phosphorylation sites. We developed a computational platform (ReKINect) to identify NAMs and systematically interpreted the exomes and quantitative (phospho-)proteomes of five ovarian cancer cell lines and the global cancer genome repository. We identified......-inactivating hotspots in cancer. Our method pinpoints functional NAMs, scales with the complexity of cancer genomes and cell signaling, and may enhance our capability to therapeutically target tumor-specific networks....

  13. Light-induced rewiring and winding of Saturn ring defects in photosensitive chiral nematic colloids. (United States)

    Gvozdovskyy, I; Jampani, V S R; Skarabot, M; Muševič, I


    We study the winding and unwinding of Saturn ring defects around silica microspheres with homeotropic surface anchoring in a cholesteric liquid crystal with a variable pitch. We use mixtures of a nematic liquid crystal 5CB and various photoresponsive chiral dopants to vary the helical pitch and sense of the helical winding by illuminating the mixtures with UV or visible light. Upon illumination, we observe motion of the Grandjean-Cano disclination lines in wedge-like cells. When the line touches the colloidal particle, we observe topological reconstruction of the Grandjean-Cano line and the Saturn ring. The result of this topological reconstruction is either an increase or decrease of the degree of winding of the Saturn ring around the colloidal particle. This phenomenon is similar to topological rewiring of -1/2 disclination lines, observed recently in chiral nematic colloids.

  14. Transcriptional rewiring of the sex determining dmrt1 gene duplicate by transposable elements.

    Directory of Open Access Journals (Sweden)

    Amaury Herpin


    Full Text Available Control and coordination of eukaryotic gene expression rely on transcriptional and posttranscriptional regulatory networks. Evolutionary innovations and adaptations often require rapid changes of such networks. It has long been hypothesized that transposable elements (TE might contribute to the rewiring of regulatory interactions. More recently it emerged that TEs might bring in ready-to-use transcription factor binding sites to create alterations to the promoters by which they were captured. A process where the gene regulatory architecture is of remarkable plasticity is sex determination. While the more downstream components of the sex determination cascades are evolutionary conserved, the master regulators can switch between groups of organisms even on the interspecies level or between populations. In the medaka fish (Oryzias latipes a duplicated copy of dmrt1, designated dmrt1bY or DMY, on the Y chromosome was shown to be the master regulator of male development, similar to Sry in mammals. We found that the dmrt1bY gene has acquired a new feedback downregulation of its expression. Additionally, the autosomal dmrt1a gene is also able to regulate transcription of its duplicated paralog by binding to a unique target Dmrt1 site nested within the dmrt1bY proximal promoter region. We could trace back this novel regulatory element to a highly conserved sequence within a new type of TE that inserted into the upstream region of dmrt1bY shortly after the duplication event. Our data provide functional evidence for a role of TEs in transcriptional network rewiring for sub- and/or neo-functionalization of duplicated genes. In the particular case of dmrt1bY, this contributed to create new hierarchies of sex-determining genes.

  15. Development of structural correlations and synchronization from adaptive rewiring in networks of Kuramoto oscillators (United States)

    Papadopoulos, Lia; Kim, Jason Z.; Kurths, Jürgen; Bassett, Danielle S.


    Synchronization of non-identical oscillators coupled through complex networks is an important example of collective behavior, and it is interesting to ask how the structural organization of network interactions influences this process. Several studies have explored and uncovered optimal topologies for synchronization by making purposeful alterations to a network. On the other hand, the connectivity patterns of many natural systems are often not static, but are rather modulated over time according to their dynamics. However, this co-evolution and the extent to which the dynamics of the individual units can shape the organization of the network itself are less well understood. Here, we study initially randomly connected but locally adaptive networks of Kuramoto oscillators. In particular, the system employs a co-evolutionary rewiring strategy that depends only on the instantaneous, pairwise phase differences of neighboring oscillators, and that conserves the total number of edges, allowing the effects of local reorganization to be isolated. We find that a simple rule—which preserves connections between more out-of-phase oscillators while rewiring connections between more in-phase oscillators—can cause initially disordered networks to organize into more structured topologies that support enhanced synchronization dynamics. We examine how this process unfolds over time, finding a dependence on the intrinsic frequencies of the oscillators, the global coupling, and the network density, in terms of how the adaptive mechanism reorganizes the network and influences the dynamics. Importantly, for large enough coupling and after sufficient adaptation, the resulting networks exhibit interesting characteristics, including degree-frequency and frequency-neighbor frequency correlations. These properties have previously been associated with optimal synchronization or explosive transitions in which the networks were constructed using global information. On the contrary, by

  16. Effects of time delay and random rewiring on the stochastic resonance in excitable small-world neuronal networks. (United States)

    Yu, Haitao; Wang, Jiang; Du, Jiwei; Deng, Bin; Wei, Xile; Liu, Chen


    The effects of time delay and rewiring probability on stochastic resonance and spatiotemporal order in small-world neuronal networks are studied in this paper. Numerical results show that, irrespective of the pacemaker introduced to one single neuron or all neurons of the network, the phenomenon of stochastic resonance occurs. The time delay in the coupling process can either enhance or destroy stochastic resonance on small-world neuronal networks. In particular, appropriately tuned delays can induce multiple stochastic resonances, which appear intermittently at integer multiples of the oscillation period of the pacemaker. More importantly, it is found that the small-world topology can significantly affect the stochastic resonance on excitable neuronal networks. For small time delays, increasing the rewiring probability can largely enhance the efficiency of pacemaker-driven stochastic resonance. We argue that the time delay and the rewiring probability both play a key role in determining the ability of the small-world neuronal network to improve the noise-induced outreach of the localized subthreshold pacemaker.

  17. Measuring partner choice in plant-pollinator networks: using null models to separate rewiring and fidelity from chance. (United States)

    MacLeod, Molly; Genung, Mark A; Ascher, John S; Winfree, Rachael


    Recent studies of mutualistic networks show that interactions between partners change across years. Both biological mechanisms and chance could drive these patterns, but the relative importance of these factors has not been separated. We established a field experiment consisting of 102 monospecific plots of 17 native plant species, from which we collected 6713 specimens of 52 bee species over four years. We used these data and a null model to determine whether bee species' foraging choices varied more or less over time beyond the variation expected by chance. Thus we provide the first quantitative definition of rewiring and fidelity as these terms are used in the literature on interaction networks. All 52 bee species varied in plant partner choice across years, but for 27 species this variation was indistinguishable from random partner choice. Another 11 species showed rewiring, varying more across years than expected by chance, while 14 species showed fidelity, indicating that they both prefer certain plant species and are consistent in those preferences across years. Our study shows that rewiring and fidelity both exist in mutualist networks, but that once sampling effects have been accounted for, they are less common than has been reported in the ecological literature. © 2016 by the Ecological Society of America.

  18. Molecular Principles of Gene Fusion Mediated Rewiring of Protein Interaction Networks in Cancer. (United States)

    Latysheva, Natasha S; Oates, Matt E; Maddox, Louis; Flock, Tilman; Gough, Julian; Buljan, Marija; Weatheritt, Robert J; Babu, M Madan


    Gene fusions are common cancer-causing mutations, but the molecular principles by which fusion protein products affect interaction networks and cause disease are not well understood. Here, we perform an integrative analysis of the structural, interactomic, and regulatory properties of thousands of putative fusion proteins. We demonstrate that genes that form fusions (i.e., parent genes) tend to be highly connected hub genes, whose protein products are enriched in structured and disordered interaction-mediating features. Fusion often results in the loss of these parental features and the depletion of regulatory sites such as post-translational modifications. Fusion products disproportionately connect proteins that did not previously interact in the protein interaction network. In this manner, fusion products can escape cellular regulation and constitutively rewire protein interaction networks. We suggest that the deregulation of central, interaction-prone proteins may represent a widespread mechanism by which fusion proteins alter the topology of cellular signaling pathways and promote cancer. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

  19. Re-wiring of energy metabolism promotes viability during hyperreplication stress in E. coli.

    Directory of Open Access Journals (Sweden)

    Godefroid Charbon


    Full Text Available Chromosome replication in Escherichia coli is initiated by DnaA. DnaA binds ATP which is essential for formation of a DnaA-oriC nucleoprotein complex that promotes strand opening, helicase loading and replisome assembly. Following initiation, DnaAATP is converted to DnaAADP primarily by the Regulatory Inactivation of DnaA process (RIDA. In RIDA deficient cells, DnaAATP accumulates leading to uncontrolled initiation of replication and cell death by accumulation of DNA strand breaks. Mutations that suppress RIDA deficiency either dampen overinitiation or permit growth despite overinitiation. We characterize mutations of the last group that have in common that distinct metabolic routes are rewired resulting in the redirection of electron flow towards the cytochrome bd-1. We propose a model where cytochrome bd-1 lowers the formation of reactive oxygen species and hence oxidative damage to the DNA in general. This increases the processivity of replication forks generated by overinitiation to a level that sustains viability.

  20. RANK rewires energy homeostasis in lung cancer cells and drives primary lung cancer. (United States)

    Rao, Shuan; Sigl, Verena; Wimmer, Reiner Alois; Novatchkova, Maria; Jais, Alexander; Wagner, Gabriel; Handschuh, Stephan; Uribesalgo, Iris; Hagelkruys, Astrid; Kozieradzki, Ivona; Tortola, Luigi; Nitsch, Roberto; Cronin, Shane J; Orthofer, Michael; Branstetter, Daniel; Canon, Jude; Rossi, John; D'Arcangelo, Manolo; Botling, Johan; Micke, Patrick; Fleur, Linnea La; Edlund, Karolina; Bergqvist, Michael; Ekman, Simon; Lendl, Thomas; Popper, Helmut; Takayanagi, Hiroshi; Kenner, Lukas; Hirsch, Fred R; Dougall, William; Penninger, Josef M


    Lung cancer is the leading cause of cancer deaths. Besides smoking, epidemiological studies have linked female sex hormones to lung cancer in women; however, the underlying mechanisms remain unclear. Here we report that the receptor activator of nuclear factor-kB (RANK), the key regulator of osteoclastogenesis, is frequently expressed in primary lung tumors, an active RANK pathway correlates with decreased survival, and pharmacologic RANK inhibition reduces tumor growth in patient-derived lung cancer xenografts. Clonal genetic inactivation of KRas G12D in mouse lung epithelial cells markedly impairs the progression of KRas G12D -driven lung cancer, resulting in a significant survival advantage. Mechanistically, RANK rewires energy homeostasis in human and murine lung cancer cells and promotes expansion of lung cancer stem-like cells, which is blocked by inhibiting mitochondrial respiration. Our data also indicate survival differences in KRas G12D -driven lung cancer between male and female mice, and we show that female sex hormones can promote lung cancer progression via the RANK pathway. These data uncover a direct role for RANK in lung cancer and may explain why female sex hormones accelerate lung cancer development. Inhibition of RANK using the approved drug denosumab may be a therapeutic drug candidate for primary lung cancer. © 2017 Rao et al.; Published by Cold Spring Harbor Laboratory Press.

  1. Resilience and rewiring of the passenger airline networks in the United States (United States)

    Wuellner, Daniel R.; Roy, Soumen; D'Souza, Raissa M.


    The air transportation network, a fundamental component of critical infrastructure, is formed from a collection of individual air carriers, each one with a methodically designed and engineered network structure. We analyze the individual structures of the seven largest passenger carriers in the USA and find that networks with dense interconnectivity, as quantified by large k cores for high values of k , are extremely resilient to both targeted removal of airports (nodes) and random removal of flight paths (edges). Such networks stay connected and incur minimal increase in an heuristic travel time despite removal of a majority of nodes or edges. Similar results are obtained for targeted removal based on either node degree or centrality. We introduce network rewiring schemes that boost resilience to different levels of perturbation while preserving total number of flight and gate requirements. Recent studies have focused on the asymptotic optimality of hub-and-spoke spatial networks under normal operating conditions, yet our results indicate that point-to-point architectures can be much more resilient to perturbations.

  2. Search for the Heisenberg spin glass on rewired square lattices with antiferromagnetic interaction

    International Nuclear Information System (INIS)

    Surungan, Tasrief; Bansawang, B.J.; Tahir, Dahlang


    Spin glass (SG) is a typical magnetic system with frozen random spin orientation at low temperatures. The system exhibits rich physical properties, such as infinite number of ground states, memory effect, and aging phenomena. There are two main ingredients considered to be pivotal for the existence of SG behavior, namely, frustration and randomness. For the canonical SG system, frustration is led by the presence of competing interaction between ferromagnetic (FM) and antiferromagnetic (AF) couplings. Previously, Bartolozzi et al. [Phys. Rev. B73, 224419 (2006)], reported the SG properties of the AF Ising spins on scale free network (SFN). It is a new type of SG, different from the canonical one which requires the presence of both FM and AF couplings. In this new system, frustration is purely caused by the topological factor and its randomness is related to the irregular connectvity. Recently, Surungan et. al. [Journal of Physics: Conference Series, 640, 012001 (2015)] reported SG bahavior of AF Heisenberg model on SFN. We further investigate this type of system by studying an AF Heisenberg model on rewired square lattices. We used Replica Exchange algorithm of Monte Carlo Method and calculated the SG order parameter to search for the existence of SG phase.

  3. Search for the Heisenberg spin glass on rewired cubic lattices with antiferromagnetic interaction

    International Nuclear Information System (INIS)

    Surungan, Tasrief


    Spin glass (SG) is a typical magnetic system which is mainly characterized by a frozen random spin orientation at low temperatures. Frustration and randomness are considered to be the key ingredients for the existence of SGs. Previously, Bartolozzi et al . [Phys. Rev. B73, 224419 (2006)] found that the antiferromagnetic (AF) Ising spins on scale free network (SFN) exhibited SG behavior. This is purely AF system, a new type of SG different from the canonical one which requires the presence of both FM and AF couplings. In this new system, frustration is purely due to a topological factor and its randomness is brought by irregular connectivity. Recently, it was reported that the AF Heisenberg model on SFN exhibited SG behavior [Surungan et al ., JPCS, 640, 012005 (2015)/doi:10.1088/1742-6596/640/1/012005]. In order to accommodate the notion of spatial dimension, we further investigated this type of system by studying an AF Heisenberg model on rewired cubic lattices, constructed by adding one extra bond randomly connecting each spin to one of its next-nearest neighbors. We used Replica Exchange algorithm of Monte Carlo Method and calculated the SG order parameter to search for the existence of SG phase. (paper)

  4. Extensive and systematic rewiring of histone post-translational modifications in cancer model systems. (United States)

    Noberini, Roberta; Osti, Daniela; Miccolo, Claudia; Richichi, Cristina; Lupia, Michela; Corleone, Giacomo; Hong, Sung-Pil; Colombo, Piergiuseppe; Pollo, Bianca; Fornasari, Lorenzo; Pruneri, Giancarlo; Magnani, Luca; Cavallaro, Ugo; Chiocca, Susanna; Minucci, Saverio; Pelicci, Giuliana; Bonaldi, Tiziana


    Histone post-translational modifications (PTMs) generate a complex combinatorial code that regulates gene expression and nuclear functions, and whose deregulation has been documented in different types of cancers. Therefore, the availability of relevant culture models that can be manipulated and that retain the epigenetic features of the tissue of origin is absolutely crucial for studying the epigenetic mechanisms underlying cancer and testing epigenetic drugs. In this study, we took advantage of quantitative mass spectrometry to comprehensively profile histone PTMs in patient tumor tissues, primary cultures and cell lines from three representative tumor models, breast cancer, glioblastoma and ovarian cancer, revealing an extensive and systematic rewiring of histone marks in cell culture conditions, which includes a decrease of H3K27me2/me3, H3K79me1/me2 and H3K9ac/K14ac, and an increase of H3K36me1/me2. While some changes occur in short-term primary cultures, most of them are instead time-dependent and appear only in long-term cultures. Remarkably, such changes mostly revert in cell line- and primary cell-derived in vivo xenograft models. Taken together, these results support the use of xenografts as the most representative models of in vivo epigenetic processes, suggesting caution when using cultured cells, in particular cell lines and long-term primary cultures, for epigenetic investigations.

  5. The Rewiring of Ubiquitination Targets in a Pathogenic Yeast Promotes Metabolic Flexibility, Host Colonization and Virulence.

    Directory of Open Access Journals (Sweden)

    Delma S Childers


    Full Text Available Efficient carbon assimilation is critical for microbial growth and pathogenesis. The environmental yeast Saccharomyces cerevisiae is "Crabtree positive", displaying a rapid metabolic switch from the assimilation of alternative carbon sources to sugars. Following exposure to sugars, this switch is mediated by the transcriptional repression of genes (carbon catabolite repression and the turnover (catabolite inactivation of enzymes involved in the assimilation of alternative carbon sources. The pathogenic yeast Candida albicans is Crabtree negative. It has retained carbon catabolite repression mechanisms, but has undergone posttranscriptional rewiring such that gluconeogenic and glyoxylate cycle enzymes are not subject to ubiquitin-mediated catabolite inactivation. Consequently, when glucose becomes available, C. albicans can continue to assimilate alternative carbon sources alongside the glucose. We show that this metabolic flexibility promotes host colonization and virulence. The glyoxylate cycle enzyme isocitrate lyase (CaIcl1 was rendered sensitive to ubiquitin-mediated catabolite inactivation in C. albicans by addition of a ubiquitination site. This mutation, which inhibits lactate assimilation in the presence of glucose, reduces the ability of C. albicans cells to withstand macrophage killing, colonize the gastrointestinal tract and cause systemic infections in mice. Interestingly, most S. cerevisiae clinical isolates we examined (67% have acquired the ability to assimilate lactate in the presence of glucose (i.e. they have become Crabtree negative. These S. cerevisiae strains are more resistant to macrophage killing than Crabtree positive clinical isolates. Moreover, Crabtree negative S. cerevisiae mutants that lack Gid8, a key component of the Glucose-Induced Degradation complex, are more resistant to macrophage killing and display increased virulence in immunocompromised mice. Thus, while Crabtree positivity might impart a fitness

  6. Differential regulation of polarized synaptic vesicle trafficking and synapse stability in neural circuit rewiring in Caenorhabditis elegans.

    Directory of Open Access Journals (Sweden)

    Naina Kurup


    Full Text Available Neural circuits are dynamic, with activity-dependent changes in synapse density and connectivity peaking during different phases of animal development. In C. elegans, young larvae form mature motor circuits through a dramatic switch in GABAergic neuron connectivity, by concomitant elimination of existing synapses and formation of new synapses that are maintained throughout adulthood. We have previously shown that an increase in microtubule dynamics during motor circuit rewiring facilitates new synapse formation. Here, we further investigate cellular control of circuit rewiring through the analysis of mutants obtained in a forward genetic screen. Using live imaging, we characterize novel mutations that alter cargo binding in the dynein motor complex and enhance anterograde synaptic vesicle movement during remodeling, providing in vivo evidence for the tug-of-war between kinesin and dynein in fast axonal transport. We also find that a casein kinase homolog, TTBK-3, inhibits stabilization of nascent synapses in their new locations, a previously unexplored facet of structural plasticity of synapses. Our study delineates temporally distinct signaling pathways that are required for effective neural circuit refinement.

  7. Enriched and Deprived Sensory Experience Induces Structural Changes and Rewires Connectivity during the Postnatal Development of the Brain

    Directory of Open Access Journals (Sweden)

    Harkaitz Bengoetxea


    Full Text Available During postnatal development, sensory experience modulates cortical development, inducing numerous changes in all of the components of the cortex. Most of the cortical changes thus induced occur during the critical period, when the functional and structural properties of cortical neurons are particularly susceptible to alterations. Although the time course for experience-mediated sensory development is specific for each system, postnatal development acts as a whole, and if one cortical area is deprived of its normal sensory inputs during early stages, it will be reorganized by the nondeprived senses in a process of cross-modal plasticity that not only increases performance in the remaining senses when one is deprived, but also rewires the brain allowing the deprived cortex to process inputs from other senses and cortices, maintaining the modular configuration. This paper summarizes our current understanding of sensory systems development, focused specially in the visual system. It delineates sensory enhancement and sensory deprivation effects at both physiological and anatomical levels and describes the use of enriched environment as a tool to rewire loss of brain areas to enhance other active senses. Finally, strategies to apply restorative features in human-deprived senses are studied, discussing the beneficial and detrimental effects of cross-modal plasticity in prostheses and sensory substitution devices implantation.

  8. Metabolic Rewiring by Oncogenic BRAF V600E Links Ketogenesis Pathway to BRAF-MEK1 Signaling. (United States)

    Kang, Hee-Bum; Fan, Jun; Lin, Ruiting; Elf, Shannon; Ji, Quanjiang; Zhao, Liang; Jin, Lingtao; Seo, Jae Ho; Shan, Changliang; Arbiser, Jack L; Cohen, Cynthia; Brat, Daniel; Miziorko, Henry M; Kim, Eunhee; Abdel-Wahab, Omar; Merghoub, Taha; Fröhling, Stefan; Scholl, Claudia; Tamayo, Pablo; Barbie, David A; Zhou, Lu; Pollack, Brian P; Fisher, Kevin; Kudchadkar, Ragini R; Lawson, David H; Sica, Gabriel; Rossi, Michael; Lonial, Sagar; Khoury, Hanna J; Khuri, Fadlo R; Lee, Benjamin H; Boggon, Titus J; He, Chuan; Kang, Sumin; Chen, Jing


    Many human cancers share similar metabolic alterations, including the Warburg effect. However, it remains unclear whether oncogene-specific metabolic alterations are required for tumor development. Here we demonstrate a "synthetic lethal" interaction between oncogenic BRAF V600E and a ketogenic enzyme 3-hydroxy-3-methylglutaryl-CoA lyase (HMGCL). HMGCL expression is upregulated in BRAF V600E-expressing human primary melanoma and hairy cell leukemia cells. Suppression of HMGCL specifically attenuates proliferation and tumor growth potential of human melanoma cells expressing BRAF V600E. Mechanistically, active BRAF upregulates HMGCL through an octamer transcription factor Oct-1, leading to increased intracellular levels of HMGCL product, acetoacetate, which selectively enhances binding of BRAF V600E but not BRAF wild-type to MEK1 in V600E-positive cancer cells to promote activation of MEK-ERK signaling. These findings reveal a mutation-specific mechanism by which oncogenic BRAF V600E "rewires" metabolic and cell signaling networks and signals through the Oct-1-HMGCL-acetoacetate axis to selectively promote BRAF V600E-dependent tumor development. Copyright © 2015 Elsevier Inc. All rights reserved.

  9. Linalool is a PPARα ligand that reduces plasma TG levels and rewires the hepatic transcriptome and plasma metabolome. (United States)

    Jun, Hee-Jin; Lee, Ji Hae; Kim, Jiyoung; Jia, Yaoyao; Kim, Kyoung Heon; Hwang, Kwang Yeon; Yun, Eun Ju; Do, Kyoung-Rok; Lee, Sung-Joon


    We investigated the hypotriglyceridemic mechanism of action of linalool, an aromatic monoterpene present in teas and fragrant herbs. Reporter gene and time-resolved fluorescence resonance energy transfer assays demonstrated that linalool is a direct ligand of PPARα. Linalool stimulation reduced cellular lipid accumulation regulating PPARα-responsive genes and significantly induced FA oxidation, and its effects were markedly attenuated by silencing PPARα expression. In mice, the oral administration of linalool for 3 weeks reduced plasma TG concentrations in Western-diet-fed C57BL/6J mice (31%, P linalool stimulation rewired global gene expression in lipid-loaded hepatocytes and that the effects of 1 mM linalool were comparable to those of 0.1 mM fenofibrate. Metabolomic analysis of the mouse plasma revealed that the global metabolite profiles were significantly distinguishable between linalool-fed mice and controls. Notably, the concentrations of saturated FAs were significantly reduced in linalool-fed mice. These findings suggest that the appropriate intake of a natural aromatic compound could exert beneficial metabolic effects by regulating a cellular nutrient sensor. Copyright © 2014 by the American Society for Biochemistry and Molecular Biology, Inc.

  10. Linalool is a PPARα ligand that reduces plasma TG levels and rewires the hepatic transcriptome and plasma metabolome[S (United States)

    Jun, Hee-jin; Lee, Ji Hae; Kim, Jiyoung; Jia, Yaoyao; Kim, Kyoung Heon; Hwang, Kwang Yeon; Yun, Eun Ju; Do, Kyoung-Rok; Lee, Sung-Joon


    We investigated the hypotriglyceridemic mechanism of action of linalool, an aromatic monoterpene present in teas and fragrant herbs. Reporter gene and time-resolved fluorescence resonance energy transfer assays demonstrated that linalool is a direct ligand of PPARα. Linalool stimulation reduced cellular lipid accumulation regulating PPARα-responsive genes and significantly induced FA oxidation, and its effects were markedly attenuated by silencing PPARα expression. In mice, the oral administration of linalool for 3 weeks reduced plasma TG concentrations in Western-diet-fed C57BL/6J mice (31%, P linalool stimulation rewired global gene expression in lipid-loaded hepatocytes and that the effects of 1 mM linalool were comparable to those of 0.1 mM fenofibrate. Metabolomic analysis of the mouse plasma revealed that the global metabolite profiles were significantly distinguishable between linalool-fed mice and controls. Notably, the concentrations of saturated FAs were significantly reduced in linalool-fed mice. These findings suggest that the appropriate intake of a natural aromatic compound could exert beneficial metabolic effects by regulating a cellular nutrient sensor. PMID:24752549

  11. A UV-Induced Genetic Network Links the RSC Complex to Nucleotide Excision Repair and Shows Dose-Dependent Rewiring

    Directory of Open Access Journals (Sweden)

    Rohith Srivas


    Full Text Available Efficient repair of UV-induced DNA damage requires the precise coordination of nucleotide excision repair (NER with numerous other biological processes. To map this crosstalk, we generated a differential genetic interaction map centered on quantitative growth measurements of >45,000 double mutants before and after different doses of UV radiation. Integration of genetic data with physical interaction networks identified a global map of 89 UV-induced functional interactions among 62 protein complexes, including a number of links between the RSC complex and several NER factors. We show that RSC is recruited to both silenced and transcribed loci following UV damage where it facilitates efficient repair by promoting nucleosome remodeling. Finally, a comparison of the response to high versus low levels of UV shows that the degree of genetic rewiring correlates with dose of UV and reveals a network of dose-specific interactions. This study makes available a large resource of UV-induced interactions, and it illustrates a methodology for identifying dose-dependent interactions based on quantitative shifts in genetic networks.

  12. Robust Regression Analysis of GCMS Data Reveals Differential Rewiring of Metabolic Networks in Hepatitis B and C Patients

    Directory of Open Access Journals (Sweden)

    Cedric Simillion


    Full Text Available About one in 15 of the world’s population is chronically infected with either hepatitis virus B (HBV or C (HCV, with enormous public health consequences. The metabolic alterations caused by these infections have never been directly compared and contrasted. We investigated groups of HBV-positive, HCV-positive, and uninfected healthy controls using gas chromatography-mass spectrometry analyses of their plasma and urine. A robust regression analysis of the metabolite data was conducted to reveal correlations between metabolite pairs. Ten metabolite correlations appeared for HBV plasma and urine, with 18 for HCV plasma and urine, none of which were present in the controls. Metabolic perturbation networks were constructed, which permitted a differential view of the HBV- and HCV-infected liver. HBV hepatitis was consistent with enhanced glucose uptake, glycolysis, and pentose phosphate pathway metabolism, the latter using xylitol and producing threonic acid, which may also be imported by glucose transporters. HCV hepatitis was consistent with impaired glucose uptake, glycolysis, and pentose phosphate pathway metabolism, with the tricarboxylic acid pathway fueled by branched-chain amino acids feeding gluconeogenesis and the hepatocellular loss of glucose, which most probably contributed to hyperglycemia. It is concluded that robust regression analyses can uncover metabolic rewiring in disease states.

  13. Cytotoxic Vibrio T3SS1 Rewires Host Gene Expression to Subvert Cell Death Signaling and Activate Cell Survival Networks (United States)

    De Nisco, Nicole J.; Kanchwala, Mohammed; Li, Peng; Fernandez, Jessie; Xing, Chao; Orth, Kim


    Bacterial effectors are potent manipulators of host signaling pathways. The marine bacterium Vibrio parahaemolyticus (V. para), delivers effectors into host cells through two type three secretion systems (T3SS). The ubiquitous T3SS1 is vital for V. para survival in the environment, whereas T3SS2 causes acute gastroenteritis in human hosts. Although the natural host is undefined, T3SS1 effectors attack highly conserved cellular processes and pathways to orchestrate non-apoptotic cell death. Much is known about how T3SS1 effectors function in isolation, but we wanted to understand how their concerted action globally affects host cell signaling. To assess the host response to T3SS1, we compared gene expression changes over time in primary fibroblasts infected with V. para that have a functional T3SS1 (T3SS1+) to those in cells infected with V. para lacking T3SS1 (T3SS1−). Overall, the host transcriptional response to both T3SS1+ and T3SS1− V. para was rapid, robust, and temporally dynamic. T3SS1 re-wired host gene expression by specifically altering the expression of 398 genes. Although T3SS1 effectors target host cells at the posttranslational level to cause cytotoxicity, network analysis indicated that V. para T3SS1 also precipitates a host transcriptional response that initially activates cell survival and represses cell death networks. The increased expression of several key pro-survival transcripts mediated by T3SS1 was dependent on a host signaling pathway that is silenced later in infection by the posttranslational action of T3SS1. Taken together, our analysis reveals a complex interplay between roles of T3SS1 as both a transcriptional and posttranslational manipulator of host cell signaling. PMID:28512145

  14. Rewiring the Glucose Transportation and Central Metabolic Pathways for Overproduction of N-Acetylglucosamine in Bacillus subtilis. (United States)

    Gu, Yang; Deng, Jieying; Liu, Yanfeng; Li, Jianghua; Shin, Hyun-Dong; Du, Guocheng; Chen, Jian; Liu, Long


    N-acetylglucosamine (GlcNAc) is an important amino sugar extensively used in the healthcare field. In a previous study, the recombinant Bacillus subtilis strain BSGN6-P xylA -glmS-pP43NMK-GNA1 (BN0-GNA1) had been constructed for microbial production of GlcNAc by pathway design and modular optimization. Here, the production of GlcNAc is further improved by rewiring both the glucose transportation and central metabolic pathways. First, the phosphotransferase system (PTS) is blocked by deletion of three genes, yyzE (encoding the PTS system transporter subunit IIA YyzE), ypqE (encoding the PTS system transporter subunit IIA YpqE), and ptsG (encoding the PTS system glucose-specific EIICBA component), resulting in 47.6% increase in the GlcNAc titer (from 6.5 ± 0.25 to 9.6 ± 0.16 g L -1 ) in shake flasks. Then, reinforcement of the expression of the glcP and glcK genes and optimization of glucose facilitator proteins are performed to promote glucose import and phosphorylation. Next, the competitive pathways for GlcNAc synthesis, namely glycolysis, peptidoglycan synthesis pathway, pentose phosphate pathway, and tricarboxylic acid cycle, are repressed by initiation codon-optimization strategies, and the GlcNAc titer in shake flasks is improved from 10.8 ± 0.25 to 13.2 ± 0.31 g L -1 . Finally, the GlcNAc titer is further increased to 42.1 ± 1.1 g L -1 in a 3-L fed-batch bioreactor, which is 1.72-fold that of the original strain, BN0-GNA1. This study shows considerably enhanced GlcNAc production, and the metabolic engineering strategy described here will be useful for engineering other prokaryotic microorganisms for the production of GlcNAc and related molecules. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Bayesian model of signal rewiring reveals mechanisms of gene dysregulation in acquired drug resistance in breast cancer.

    Directory of Open Access Journals (Sweden)

    A K M Azad

    Full Text Available Small molecule inhibitors, such as lapatinib, are effective against breast cancer in clinical trials, but tumor cells ultimately acquire resistance to the drug. Maintaining sensitization to drug action is essential for durable growth inhibition. Recently, adaptive reprogramming of signaling circuitry has been identified as a major cause of acquired resistance. We developed a computational framework using a Bayesian statistical approach to model signal rewiring in acquired resistance. We used the p1-model to infer potential aberrant gene-pairs with differential posterior probabilities of appearing in resistant-vs-parental networks. Results were obtained using matched gene expression profiles under resistant and parental conditions. Using two lapatinib-treated ErbB2-positive breast cancer cell-lines: SKBR3 and BT474, our method identified similar dysregulated signaling pathways including EGFR-related pathways as well as other receptor-related pathways, many of which were reported previously as compensatory pathways of EGFR-inhibition via signaling cross-talk. A manual literature survey provided strong evidence that aberrant signaling activities in dysregulated pathways are closely related to acquired resistance in EGFR tyrosine kinase inhibitors. Our approach predicted literature-supported dysregulated pathways complementary to both node-centric (SPIA, DAVID, and GATHER and edge-centric (ESEA and PAGI methods. Moreover, by proposing a novel pattern of aberrant signaling called V-structures, we observed that genes were dysregulated in resistant-vs-sensitive conditions when they were involved in the switch of dependencies from targeted to bypass signaling events. A literature survey of some important V-structures suggested they play a role in breast cancer metastasis and/or acquired resistance to EGFR-TKIs, where the mRNA changes of TGFBR2, LEF1 and TP53 in resistant-vs-sensitive conditions were related to the dependency switch from targeted to

  16. Bayesian model of signal rewiring reveals mechanisms of gene dysregulation in acquired drug resistance in breast cancer (United States)

    Azad, A. K. M.; Keith, Jonathan M.


    Small molecule inhibitors, such as lapatinib, are effective against breast cancer in clinical trials, but tumor cells ultimately acquire resistance to the drug. Maintaining sensitization to drug action is essential for durable growth inhibition. Recently, adaptive reprogramming of signaling circuitry has been identified as a major cause of acquired resistance. We developed a computational framework using a Bayesian statistical approach to model signal rewiring in acquired resistance. We used the p1-model to infer potential aberrant gene-pairs with differential posterior probabilities of appearing in resistant-vs-parental networks. Results were obtained using matched gene expression profiles under resistant and parental conditions. Using two lapatinib-treated ErbB2-positive breast cancer cell-lines: SKBR3 and BT474, our method identified similar dysregulated signaling pathways including EGFR-related pathways as well as other receptor-related pathways, many of which were reported previously as compensatory pathways of EGFR-inhibition via signaling cross-talk. A manual literature survey provided strong evidence that aberrant signaling activities in dysregulated pathways are closely related to acquired resistance in EGFR tyrosine kinase inhibitors. Our approach predicted literature-supported dysregulated pathways complementary to both node-centric (SPIA, DAVID, and GATHER) and edge-centric (ESEA and PAGI) methods. Moreover, by proposing a novel pattern of aberrant signaling called V-structures, we observed that genes were dysregulated in resistant-vs-sensitive conditions when they were involved in the switch of dependencies from targeted to bypass signaling events. A literature survey of some important V-structures suggested they play a role in breast cancer metastasis and/or acquired resistance to EGFR-TKIs, where the mRNA changes of TGFBR2, LEF1 and TP53 in resistant-vs-sensitive conditions were related to the dependency switch from targeted to bypass signaling links

  17. Combinatorial control of adhesion of Brucella abortus 2308 to host cells by transcriptional rewiring of the trimeric autotransporter btaE gene. (United States)

    Sieira, Rodrigo; Bialer, Magalí G; Roset, Mara S; Ruiz-Ranwez, Verónica; Langer, Tomás; Arocena, Gastón M; Mancini, Estefanía; Zorreguieta, Angeles


    Regulatory network plasticity is a key attribute underlying changes in bacterial gene expression and a source of phenotypic diversity to interact with the surrounding environment. Here, we sought to study the transcriptional circuit of HutC, a regulator of both metabolic and virulence genes of the facultative intracellular pathogen Brucella. Using in silico and biochemical approaches, we identified a novel functional HutC-binding site upstream of btaE, a trimeric-autotransporter adhesin involved in the attachment of Brucella to host extracellular matrix components. Moreover, we identified two additional regulators, one of which, MdrA, acts in concert with HutC to exert a combinatorial control of both btaE promoter activity and attachment of Brucella to HeLa cells. Analysis of btaE promoter sequences of different species indicated that this HutC-binding site was generated de novo by a single point mutation in a virulent Brucella strain, indicative of a transcriptional rewiring event. In addition to major domain organization differences existing between BtaE proteins within the genus Brucella, our analyses revealed that sequences upstream of btaE display high variability probably associated to intrinsic promoter structural features, which may serve as a substrate for reciprocal selection during co-evolution between this pathogen and its mammalian host. © 2016 John Wiley & Sons Ltd.

  18. Evolutionary re-wiring of p63 and the epigenomic regulatory landscape in keratinocytes and its potential implications on species-specific gene expression and phenotypes (United States)

    Sethi, Isha; Gluck, Christian; Zhou, Huiqing


    Abstract Although epidermal keratinocyte development and differentiation proceeds in similar fashion between humans and mice, evolutionary pressures have also wrought significant species-specific physiological differences. These differences between species could arise in part, by the rewiring of regulatory network due to changes in the global targets of lineage-specific transcriptional master regulators such as p63. Here we have performed a systematic and comparative analysis of the p63 target gene network within the integrated framework of the transcriptomic and epigenomic landscape of mouse and human keratinocytes. We determined that there exists a core set of ∼1600 genomic regions distributed among enhancers and super-enhancers, which are conserved and occupied by p63 in keratinocytes from both species. Notably, these DNA segments are typified by consensus p63 binding motifs under purifying selection and are associated with genes involved in key keratinocyte and skin-centric biological processes. However, the majority of the p63-bound mouse target regions consist of either murine-specific DNA elements that are not alignable to the human genome or exhibit no p63 binding in the orthologous syntenic regions, typifying an occupancy lost subset. Our results suggest that these evolutionarily divergent regions have undergone significant turnover of p63 binding sites and are associated with an underlying inactive and inaccessible chromatin state, indicative of their selective functional activity in the transcriptional regulatory network in mouse but not human. Furthermore, we demonstrate that this selective targeting of genes by p63 correlates with subtle, but measurable transcriptional differences in mouse and human keratinocytes that converges on major metabolic processes, which often exhibit species-specific trends. Collectively our study offers possible molecular explanation for the observable phenotypic differences between the mouse and human skin and broadly

  19. The cytotoxic type 3 secretion system 1 of Vibrio rewires host gene expression to subvert cell death and activate cell survival pathways. (United States)

    De Nisco, Nicole J; Kanchwala, Mohammed; Li, Peng; Fernandez, Jessie; Xing, Chao; Orth, Kim


    Bacterial effectors potently manipulate host signaling pathways. The marine bacterium Vibrio parahaemolyticus ( V. para ) delivers effectors into host cells through two type 3 secretion systems (T3SSs). T3SS1 is vital for V. para survival in the environment, whereas T3SS2 causes acute gastroenteritis in human hosts. Although the natural host is undefined, T3SS1 effectors attack highly conserved cellular processes and pathways to orchestrate nonapoptotic cell death. To understand how the concerted action of T3SS1 effectors globally affects host cell signaling, we compared gene expression changes over time in primary fibroblasts infected with V. para that have a functional T3SS1 (T3SS1 + ) to those in cells infected with V. para lacking T3SS1 (T3SS1 - ). Overall, the host transcriptional response to both T3SS1 + and T3SS1 - V. para was rapid, robust, and temporally dynamic. T3SS1 rewired host gene expression by specifically altering the expression of 398 genes. Although T3SS1 effectors targeted host cells at the posttranslational level to cause cytotoxicity, V. para T3SS1 also precipitated a host transcriptional response that initially activated cell survival and repressed cell death networks. The increased expression of several key prosurvival transcripts mediated by T3SS1 depended on a host signaling pathway that is silenced posttranslationally later in infection. Together, our analysis reveals a complex interplay between the roles of T3SS1 as both a transcriptional and posttranslational manipulator of host cell signaling. Copyright © 2017, American Association for the Advancement of Science.

  20. A high throughput amenable Arabidopsis-P. aeruginosa system reveals a rewired regulatory module and the utility to identify potent anti-infectives.

    Directory of Open Access Journals (Sweden)

    Suresh Gopalan


    Full Text Available We previously demonstrated that in a metasystem consisting of Arabidopsis seedlings growing in liquid medium (in 96 well plates even microbes considered to be innocuous such as laboratory strains of E. coli and B. subtilis can cause potent damage to the host. We further posited that such environment-induced adaptations are brought about by 'system status changes' (rewiring of pre-existing cellular signaling networks and components of the host and the microbe, and that prolongation of such a situation could lead to the emergence of pathogenic states in real-life. Here, using this infection model, we show that the master regulator GacA of the human opportunistic pathogen P. aeruginosa (strain PA14 is dispensable for pathogenesis, as evidenced by three independent read-outs. The gene expression profile of the host after infection with wild type PA14 or the gacA mutant are also identical. GacA normally acts upstream of the quorum sensing regulatory circuit (that includes the regulator LasR that controls a subset of virulence factors. Double mutants in gacA and lasR behave similar to the lasR mutant, as seen by abrogation of a characteristic cell type specific host cell damage caused by PA14 or the gacA mutant. This indicates that a previously unrecognized regulatory mechanism is operative under these conditions upstream of LasR. In addition, the detrimental effect of PA14 on Arabidopsis seedlings is resistant to high concentrations of the aminoglycoside antibiotic gentamicin. These data suggest that the Arabidopsis seedling infection system could be used to identify anti-infectives with potentially novel modes of action.

  1. A high throughput amenable Arabidopsis-P. aeruginosa system reveals a rewired regulatory module and the utility to identify potent anti-infectives. (United States)

    Gopalan, Suresh; Ausubel, Frederick M


    We previously demonstrated that in a metasystem consisting of Arabidopsis seedlings growing in liquid medium (in 96 well plates) even microbes considered to be innocuous such as laboratory strains of E. coli and B. subtilis can cause potent damage to the host. We further posited that such environment-induced adaptations are brought about by 'system status changes' (rewiring of pre-existing cellular signaling networks and components) of the host and the microbe, and that prolongation of such a situation could lead to the emergence of pathogenic states in real-life. Here, using this infection model, we show that the master regulator GacA of the human opportunistic pathogen P. aeruginosa (strain PA14) is dispensable for pathogenesis, as evidenced by three independent read-outs. The gene expression profile of the host after infection with wild type PA14 or the gacA mutant are also identical. GacA normally acts upstream of the quorum sensing regulatory circuit (that includes the regulator LasR) that controls a subset of virulence factors. Double mutants in gacA and lasR behave similar to the lasR mutant, as seen by abrogation of a characteristic cell type specific host cell damage caused by PA14 or the gacA mutant. This indicates that a previously unrecognized regulatory mechanism is operative under these conditions upstream of LasR. In addition, the detrimental effect of PA14 on Arabidopsis seedlings is resistant to high concentrations of the aminoglycoside antibiotic gentamicin. These data suggest that the Arabidopsis seedling infection system could be used to identify anti-infectives with potentially novel modes of action.

  2. Human Cytomegalovirus Immediate-Early 1 Protein Rewires Upstream STAT3 to Downstream STAT1 Signaling Switching an IL6-Type to an IFNγ-Like Response.

    Directory of Open Access Journals (Sweden)

    Thomas Harwardt


    Full Text Available The human cytomegalovirus (hCMV major immediate-early 1 protein (IE1 is best known for activating transcription to facilitate viral replication. Here we present transcriptome data indicating that IE1 is as significant a repressor as it is an activator of host gene expression. Human cells induced to express IE1 exhibit global repression of IL6- and oncostatin M-responsive STAT3 target genes. This repression is followed by STAT1 phosphorylation and activation of STAT1 target genes normally induced by IFNγ. The observed repression and subsequent activation are both mediated through the same region (amino acids 410 to 445 in the C-terminal domain of IE1, and this region serves as a binding site for STAT3. Depletion of STAT3 phenocopies the STAT1-dependent IFNγ-like response to IE1. In contrast, depletion of the IL6 receptor (IL6ST or the STAT kinase JAK1 prevents this response. Accordingly, treatment with IL6 leads to prolonged STAT1 instead of STAT3 activation in wild-type IE1 expressing cells, but not in cells expressing a mutant protein (IE1dl410-420 deficient for STAT3 binding. A very similar STAT1-directed response to IL6 is also present in cells infected with a wild-type or revertant hCMV, but not an IE1dl410-420 mutant virus, and this response results in restricted viral replication. We conclude that IE1 is sufficient and necessary to rewire upstream IL6-type to downstream IFNγ-like signaling, two pathways linked to opposing actions, resulting in repressed STAT3- and activated STAT1-responsive genes. These findings relate transcriptional repressor and activator functions of IE1 and suggest unexpected outcomes relevant to viral pathogenesis in response to cytokines or growth factors that signal through the IL6ST-JAK1-STAT3 axis in hCMV-infected cells. Our results also reveal that IE1, a protein considered to be a key activator of the hCMV productive cycle, has an unanticipated role in tempering viral replication.

  3. Ear Problems (United States)

    ... Infants and Children Chest Pain, Acute Chest Pain, Chronic Cold and Flu Cough Diarrhea Ear Problems Elimination Problems Elimination Problems in Infants and Children Eye Problems Facial Swelling Feeding Problems in Infants ...

  4. Urination Problems (United States)

    ... Infants and Children Chest Pain, Acute Chest Pain, Chronic Cold and Flu Cough Diarrhea Ear Problems Elimination Problems Elimination Problems in Infants and Children Eye Problems Facial Swelling Feeding Problems in Infants ...

  5. Problems in problem analysis

    DEFF Research Database (Denmark)

    Almegaard, Henrik


    The majority of literature on engineering design methods is focused on the processes of fulfilling the design goals as efficiently as possible. This paper will focus on - and discuss - the processes of determining the design goals: the specifications. The purpose is to draw attention to the inher...... to the inherent problems, dilemmas and possibilities in these processes bearing in mind that that the most important decisions in a design project are taken in the beginning of the project....

  6. Balance Problems (United States)

    ... often, it could be a sign of a balance problem. Balance problems can make you feel unsteady. You may ... related injuries, such as a hip fracture. Some balance problems are due to problems in the inner ...

  7. [Population problem, comprehension problem]. (United States)

    Tallon, F


    Overpopulation of developing countries in general, and Rwanda in particular, is not just their problem but a problem for developed countries as well. Rapid population growth is a key factor in the increase of poverty in sub-Saharan Africa. Population growth outstrips food production. Africa receives more and more foreign food, economic, and family planning aid each year. The Government of Rwanda encourages reduced population growth. Some people criticize it, but this criticism results in mortality and suffering. One must combat this ignorance, but attitudes change slowly. Some of these same people find the government's acceptance of family planning an invasion of their privacy. Others complain that rich countries do not have campaigns to reduce births, so why should Rwanda do so? The rate of schooling does not increase in Africa, even though the number of children in school increases, because of rapid population growth. Education is key to improvements in Africa's socioeconomic growth. Thus, Africa, is underpopulated in terms of potentiality but overpopulated in terms of reality, current conditions, and possibilities of overexploitation. Africa needs to invest in human resources. Families need to save, and to so, they must refrain from having many children. Africa should resist the temptation to waste, as rich countries do, and denounce it. Africa needs to become more independent of these countries, but structural adjustment plans, growing debt, and rapid population growth limit national independence. Food aid is a means for developed countries to dominate developing countries. Modernization through foreign aid has had some positive effects on developing countries (e.g., improved hygiene, mortality reduction), but these also sparked rapid population growth. Rwandan society is no longer traditional, but it is also not yet modern. A change in mentality to fewer births, better quality of life for living infants, better education, and less burden for women must occur

  8. Speech Problems (United States)

    ... Staying Safe Videos for Educators Search English Español Speech Problems KidsHealth / For Teens / Speech Problems What's in ... a person's ability to speak clearly. Some Common Speech and Language Disorders Stuttering is a problem that ...

  9. Hemiequilibrium problems

    Directory of Open Access Journals (Sweden)

    Muhammad Aslam Noor


    Full Text Available We consider a new class of equilibrium problems, known as hemiequilibrium problems. Using the auxiliary principle technique, we suggest and analyze a class of iterative algorithms for solving hemiequilibrium problems, the convergence of which requires either pseudomonotonicity or partially relaxed strong monotonicity. As a special case, we obtain a new method for hemivariational inequalities. Since hemiequilibrium problems include hemivariational inequalities and equilibrium problems as special cases, the results proved in this paper still hold for these problems.

  10. Problem gambling. (United States)

    Thomas, Shane


    Problem gambling is an increasingly common problem in Australia. General practitioners (GPs) have an important role in ensuring that problem gambling is detected and treated. We review the clinical issues associated with the detection and treatment of problem gambling. At any one time 1% of the adult Australian population satisfy the clinical criteria for problem gambling; a further 4% are at a significant risk. Problem gambling frequently presents with other serious mental health conditions. There are several guidelines from the National Health and Medical Research Council and Australian Medical Association that recommend GP involvement in screening for problem gambling. Simple one-item tools are available for that purpose. GP screening and referral for problem gambling addresses the currently very low rates of treatment. Effective and durable psychological treatments are available for the treatment of problem gambling including cognitive behaviour therapy and motivational interviewing.

  11. Childbirth Problems (United States)

    ... the mother, baby, or both. Possible complications include Preterm (premature) labor, when labor starts before 37 completed weeks of pregnancy Problems with the umbilical cord Problems with the position of the baby, such as breech, in which ...

  12. Ankle Problems (United States)

    ... Read MoreDepression in Children and TeensRead MoreBMI Calculator Ankle ProblemsFollow this chart for more information about problems that can cause ankle pain. Our trusted Symptom Checker is written and ...

  13. Walking Problems (United States)

    ... your legs or feet Movement disorders such as Parkinson's disease Diseases such as arthritis or multiple sclerosis Vision or balance problems Treatment of walking problems depends on the cause. Physical therapy, surgery, or mobility aids may help.

  14. Sociale problemer

    DEFF Research Database (Denmark)

    Christensen, Anders Bøggild; Rasmussen, Tove; Bundesen, Peter Verner

    række fagfolk på tværs af det danske socialfaglige felt fokus på sociale problemer. Det diskuteres, hvad vi overhovedet forstår ved sociale problemer, hvordan de opstår, hvilke konsekvenser de har, og ikke mindst hvordan man som fagprofessionel håndterer sociale problemer i det daglige arbejde. Bogen er...... skrevet som lærebog til professionsuddannelser, hvor sociale problemer udgør en dimension, bl.a. socialrådgiver-, pædagog- og sygeplejerskeuddannelserne....

  15. Foot Problems (United States)

    ... can also cause foot problems. The Most Common Types of Foot Problems In older adults, the foot complaints encountered ... people include: Arch pain . From fallen arches (flat feet), or abnormally high arches. Tarsal tunnel syndrome . A type of pinched nerve disorder. Achilles tendonitis . Inflammation of ...

  16. Problem Periods (United States)

    ... during your menstrual cycle Premenstrual syndrome (PMS) Problem periods Getting enough sleep Looking and feeling your best Fighting germs Your sexuality What are STDs and STIs? Seeing the doctor Quizzes Links to more information on girls' bodies girlshealth glossary home Home ... Problem periods It’s common to have ...

  17. Breathing Problems (United States)

    ... getting enough air. Sometimes you can have mild breathing problems because of a stuffy nose or intense ... panic attacks Allergies If you often have trouble breathing, it is important to find out the cause.

  18. Sleep Problems (United States)

    ... For Consumers Consumer Information by Audience For Women Sleep Problems Share Tweet Linkedin Pin it More sharing ... 101 KB) En Español Medicines to Help You Sleep Tips for Better Sleep Basic Facts about Sleep ...

  19. Tongue problems (United States)

    ... Tongue pain may also occur with: Diabetic neuropathy Leukoplakia Mouth ulcers Oral cancer After menopause, some women have ... problem. Medicine may be prescribed for mouth ulcers, leukoplakia, oral cancer, and other mouth sores. Anti-inflammatory medicines ...

  20. Kidney Problems (United States)

    ... High Blood Pressure Nutrition Join our e-newsletter! Aging & Health A to Z Kidney Problems Basic Facts & ... specialize in the care of people with kidney (renal) diseases are called nephrologists . What are Kidney Diseases? ...

  1. Foot Problems (United States)

    ... Start OverDiagnosisThese thickened areas are likely to be CORNS. If they appear to have small granules in ... these problems. Self CareUse an over-the-counter corn or wart remover. Remove the dead skin after ...

  2. Popular Problems

    DEFF Research Database (Denmark)

    Skovhus, Randi Boelskifte; Thomsen, Rie


    to be’ (WPR) approach. Forty-nine empirical studies on Danish youth career guidance were included in the study. An analysis of the issues in focus resulted in nine problem categories. One of these, ‘targeting’, is analysed using the WPR approach. Finally, the article concludes that the WPR approach...... provides a constructive basis for a critical analysis and discussion of the collective empirical knowledge production on career guidance, stimulating awareness of problems and potential solutions among the career guidance community....

  3. Knapsack problems

    CERN Document Server

    Kellerer, Hans; Pisinger, David


    Thirteen years have passed since the seminal book on knapsack problems by Martello and Toth appeared. On this occasion a former colleague exclaimed back in 1990: "How can you write 250 pages on the knapsack problem?" Indeed, the definition of the knapsack problem is easily understood even by a non-expert who will not suspect the presence of challenging research topics in this area at the first glance. However, in the last decade a large number of research publications contributed new results for the knapsack problem in all areas of interest such as exact algorithms, heuristics and approximation schemes. Moreover, the extension of the knapsack problem to higher dimensions both in the number of constraints and in the num­ ber of knapsacks, as well as the modification of the problem structure concerning the available item set and the objective function, leads to a number of interesting variations of practical relevance which were the subject of intensive research during the last few years. Hence, two years ago ...

  4. Calculus problems

    CERN Document Server

    Baronti, Marco; van der Putten, Robertus; Venturi, Irene


    This book, intended as a practical working guide for students in Engineering, Mathematics, Physics, or any other field where rigorous calculus is needed, includes 450 exercises. Each chapter starts with a summary of the main definitions and results, which is followed by a selection of solved exercises accompanied by brief, illustrative comments. A selection of problems with indicated solutions rounds out each chapter. A final chapter explores problems that are not designed with a single issue in mind but instead call for the combination of a variety of techniques, rounding out the book’s coverage. Though the book’s primary focus is on functions of one real variable, basic ordinary differential equations (separation of variables, linear first order and constant coefficients ODEs) are also discussed. The material is taken from actual written tests that have been delivered at the Engineering School of the University of Genoa. Literally thousands of students have worked on these problems, ensuring their real-...

  5. Prostate Problems (United States)

    ... If you have BPH, you may need to wake up often to urinate when you sleep. If you can’t urinate at all, you should get medical help right away. Your doctor will know if you have a prostate problem based on ...

  6. [Transversal problems]. (United States)

    Mendoza Mendoza, A; Solano Reina, E


    In this worn we introduce the alterations of the occlusion in the horizontal level or transversal problems, in which lateral crossed bites appear, either with or without a deviation of the medium line, underlying its differential diagnostic and guide lines treatment through several different clinic cases.

  7. Dewey's Problem. (United States)

    Cohen, David K.


    Maintains that Dewey tried to solve social problems related to the growth of industrialism, increasing economic inequality, and political inequality. Argues that Dewey aspired to create a counterculture to correct the human and social devastation of industrial capitalism through a curriculum and instruction that rooted academic learning in…

  8. Agricultural problems

    International Nuclear Information System (INIS)

    Bickerton, George E.


    Although there were not reasons to deplore against major activity release from any of the 110 industrial reactors authorized to operate in US, the nuclear incident that occurred at the Three Mile Island Plant in 1979 urged the public conscience toward the necessity of readiness to cope with events of this type. The personnel of the Emergency Planning Office functioning in the frame of US Department of Agriculture has already participated in around 600 intervention drillings on a federal, local or state scale to plan, test or asses radiological emergency plans or to intervene locally. These exercises allowed acquiring a significant experience in elaborating emergency plans, planning the drillings, working out scenarios and evaluation of the potential impact of accidents from the agricultural point of view. We have also taken part in different international drillings among which the most recent are INEX 1 and RADEX 94. We have found on these occasions that the agricultural problems are essential preoccupations in most of the cases no matter if the context is international, national, local or of state level. The paper poses problems specifically related to milk, fruits and vegetables, soils, meat and meat products. Finally the paper discusses issues like drilling planning, alarm and notification, sampling strategy, access authorizations for farmers, removing of contamination wastes. A number of social, political and economical relating problems are also mentioned

  9. Problem: Heart Valve Stenosis (United States)

    ... Understanding Problems and Causes Heart Murmurs and Valve Disease "Innocent" Heart Murmur Problem: Valve Stenosis - Problem: Aortic Valve Stenosis - Problem: Mitral Valve Stenosis - Problem: Tricuspid Valve Stenosis - Problem: Pulmonary Valve Stenosis Problem: Mitral ...

  10. Rewiring neural interactions by micro-stimulation

    Directory of Open Access Journals (Sweden)

    James M Rebesco


    Full Text Available Plasticity is a crucial component of normal brain function and a critical mechanism for recovery from injury. In vitro, associative pairing of presynaptic spiking and stimulus-induced postsynaptic depolarization causes changes in the synaptic efficacy of the presynaptic neuron, when activated by extrinsic stimulation. In vivo, such paradigms can alter the responses of whole groups of neurons to stimulation. Here, we used in vivo spike-triggered stimulation to drive plastic changes in rat forelimb sensorimotor cortex, which we monitored using a statistical measure of functional connectivity inferred from the spiking statistics of the neurons during normal, spontaneous behavior. These induced plastic changes in inferred functional connectivity depended on the latency between trigger spike and stimulation, and appear to reflect a robust reorganization of the network. Such targeted connectivity changes might provide a tool for rerouting the flow of information through a network, with implications for both rehabilitation and brain-machine interface applications.

  11. Rewiring Lactococcus lactis for Ethanol Production

    DEFF Research Database (Denmark)

    Solem, Christian; Dehli, Tore Ibsen; Jensen, Peter Ruhdal


    to redirect the metabolism of LAB model organism Lactococcus lactis toward ethanol production. Codon-optimized Zymomonas mobilis pyruvate decarboxylase (PDC) was introduced and expressed from synthetic promoters in different strain backgrounds. In the wild-type L. lactis strain MG1363 growing on glucose, only...

  12. Genital Problems in Women (United States)

    ... Infants and Children Chest Pain, Acute Chest Pain, Chronic Cold and Flu Cough Diarrhea Ear Problems Elimination Problems Elimination Problems in Infants and Children Eye Problems Facial Swelling Feeding Problems in Infants ...

  13. Preventing Diabetes Problems (United States)

    ... Problems Diabetes & Sexual & Urologic Problems Clinical Trials Preventing Diabetes Problems View or Print All Sections Heart Disease & ... prevent or delay sexual and urologic problems. Depression & Diabetes Depression is common among people with a chronic, ...

  14. Adaptive Problem Solving (United States)


    1) problem solving architecture; (2) problem representation ; (3) heuristics and control knowledge ; and (4) algorithms. In the area of problem... language which humans use to describe problems/domains and SAS+ is a standard problem representation input language used by many planners. Given a...implemented a system, MSP, that given a specific problem, automatically generates, evaluates, and assembles different combinations of representations and

  15. Class and Home Problems: Optimization Problems (United States)

    Anderson, Brian J.; Hissam, Robin S.; Shaeiwitz, Joseph A.; Turton, Richard


    Optimization problems suitable for all levels of chemical engineering students are available. These problems do not require advanced mathematical techniques, since they can be solved using typical software used by students and practitioners. The method used to solve these problems forces students to understand the trends for the different terms…

  16. Menstrual Problems (For Parents) (United States)

    ... Staying Safe Videos for Educators Search English Español Menstrual Problems KidsHealth / For Parents / Menstrual Problems What's in ... like irregular periods or premenstrual syndrome (PMS). Common Menstrual Problems Premenstrual Syndrome (PMS) It's common for women ...

  17. Health Problems in Pregnancy (United States)

    ... problems. You may have problems because of a health condition you had before you got pregnant. You ... being pregnant with more than one baby, a health problem in a previous pregnancy, substance abuse during ...

  18. Problems in differential equations

    CERN Document Server

    Brenner, J L


    More than 900 problems and answers explore applications of differential equations to vibrations, electrical engineering, mechanics, and physics. Problem types include both routine and nonroutine, and stars indicate advanced problems. 1963 edition.

  19. Performance Contracting: Problem Definition and Problem Resolution. (United States)

    Zaharis, James K.; And Others

    This skill laboratory provides a technique for problem definition and alternative methods to gather pertinent data that surrounds a given situation. Seven skills are discussed including Kaufman's tri-level needs assessment model, intergroup building, organizational slice, force field analysis, brainstorming, problem definition, and conflict…

  20. Diagnosing plant problems (United States)

    Cheryl A. Smith


    Diagnosing Christmas tree problems can be a challenge, requiring a basic knowledge of plant culture and physiology, the effect of environmental influences on plant health, and the ability to identify the possible causes of plant problems. Developing a solution or remedy to the problem depends on a proper diagnosis, a process that requires recognition of a problem and...

  1. Differential equations problem solver

    CERN Document Server

    Arterburn, David R


    REA's Problem Solvers is a series of useful, practical, and informative study guides. Each title in the series is complete step-by-step solution guide. The Differential Equations Problem Solver enables students to solve difficult problems by showing them step-by-step solutions to Differential Equations problems. The Problem Solvers cover material ranging from the elementary to the advanced and make excellent review books and textbook companions. They're perfect for undergraduate and graduate studies.The Differential Equations Problem Solver is the perfect resource for any class, any exam, and

  2. Side Effects: Sleep Problems (United States)

    Sleep problems are a common side effect during cancer treatment. Learn how a polysomnogram can assess sleep problems. Learn about the benefits of managing sleep disorders in men and women with cancer.

  3. Traveling with breathing problems (United States)

    ... Traveling with breathing problems To use the sharing features on this page, please enable JavaScript. If you have breathing problems and you: Are short of breath most ...

  4. Challenging problems in algebra

    CERN Document Server

    Posamentier, Alfred S


    Over 300 unusual problems, ranging from easy to difficult, involving equations and inequalities, Diophantine equations, number theory, quadratic equations, logarithms, more. Detailed solutions, as well as brief answers, for all problems are provided.

  5. Social Problems in Macau


    Hao, Zhidong


    This article examines the current social problems in Macau—inequalities, problems in urban housing, traffic and transportation, air pollution, crime and deviant behaviour, and education. It does not focus on one social problem in detail; rather, it attempts to offer a broad picture of the issues from a sociological perspective. To help solve these problems, it seems that Macau has to build a stronger civil society and continue to democratise its political system. How Macau deals with these pr...

  6. The triangle scheduling problem

    NARCIS (Netherlands)

    Dürr, Christoph; Hanzálek, Zdeněk; Konrad, Christian; Seddik, Yasmina; Sitters, R.A.; Vásquez, Óscar C.; Woeginger, Gerhard


    This paper introduces a novel scheduling problem, where jobs occupy a triangular shape on the time line. This problem is motivated by scheduling jobs with different criticality levels. A measure is introduced, namely the binary tree ratio. It is shown that the Greedy algorithm solves the problem to

  7. Inverse problems of geophysics

    International Nuclear Information System (INIS)

    Yanovskaya, T.B.


    This report gives an overview and the mathematical formulation of geophysical inverse problems. General principles of statistical estimation are explained. The maximum likelihood and least square fit methods, the Backus-Gilbert method and general approaches for solving inverse problems are discussed. General formulations of linearized inverse problems, singular value decomposition and properties of pseudo-inverse solutions are given

  8. The problem of simultaneity (United States)

    Marx, G.

    Drake's formula for the possible number of independent civilizations in the Galaxy is discussed in the light of several new hypotheses (e.g., Lovelock's Gaia hypothesis). Emphasis is placed on ways to overcome the time problem, i.e., the problem of how to communicate with civilizations that may arise in the future. Electronic, nucleonic, and bionic approaches to this problem are discussed.

  9. Classifying IS Project Problems

    DEFF Research Database (Denmark)

    Munk-Madsen, Andreas


    The literature contains many lists of IS project problems, often in the form of risk factors. The problems sometimes appear unordered and overlapping, which reduces their usefulness to practitioners as well as theoreticians. This paper proposes a list of criteria for formulating project problems...

  10. Problems for Computer Mathematics. (United States)

    Allison, Ronald; And Others

    This booklet contains some 80 problems in mathematics suitable for computer solution. The problems range from very simple to complex. Problems have been included from most mathematic disciplines, including number theory, analytical geometry, probability and statistics, trigonometry, equations, and sequence and limits. For the most part these…

  11. Assessment Problems in Reading. (United States)

    MacGinitie, Walter H., Ed.

    The papers in this volume deal with a range of assessment problems in reading. The first paper, by Karlin, introduces the general problem of using assessment procedures to guide teaching. The next six papers deal with various aspects of this general problem. Otto discusses the distinction between norm-referenced, standardized achievement tests and…

  12. Semidefinite linear complementarity problems

    International Nuclear Information System (INIS)

    Eckhardt, U.


    Semidefinite linear complementarity problems arise by discretization of variational inequalities describing e.g. elastic contact problems, free boundary value problems etc. In the present paper linear complementarity problems are introduced and the theory as well as the numerical treatment of them are described. In the special case of semidefinite linear complementarity problems a numerical method is presented which combines the advantages of elimination and iteration methods without suffering from their drawbacks. This new method has very attractive properties since it has a high degree of invariance with respect to the representation of the set of all feasible solutions of a linear complementarity problem by linear inequalities. By means of some practical applications the properties of the new method are demonstrated. (orig.) [de

  13. Matrix interdiction problem

    Energy Technology Data Exchange (ETDEWEB)

    Pan, Feng [Los Alamos National Laboratory; Kasiviswanathan, Shiva [Los Alamos National Laboratory


    In the matrix interdiction problem, a real-valued matrix and an integer k is given. The objective is to remove k columns such that the sum over all rows of the maximum entry in each row is minimized. This combinatorial problem is closely related to bipartite network interdiction problem which can be applied to prioritize the border checkpoints in order to minimize the probability that an adversary can successfully cross the border. After introducing the matrix interdiction problem, we will prove the problem is NP-hard, and even NP-hard to approximate with an additive n{gamma} factor for a fixed constant {gamma}. We also present an algorithm for this problem that achieves a factor of (n-k) mUltiplicative approximation ratio.

  14. Genital Problems in Infants (Female) (United States)

    ... Infants and Children Chest Pain, Acute Chest Pain, Chronic Cold and Flu Cough Diarrhea Ear Problems Elimination Problems Elimination Problems in Infants and Children Eye Problems Facial Swelling Feeding Problems in Infants ...

  15. Distributed Problem-Solving

    DEFF Research Database (Denmark)

    Chemi, Tatiana


    a perspective that is relevant to higher education. The focus here is on how artists solve problems in distributed paths, and on the elements of creative collaboration. Creative problem-solving will be looked at as an ongoing dialogue that artists engage with themselves, with others, with recipients......, what can educators at higher education learn from the ways creative groups solve problems? How can artists contribute to inspiring higher education?...

  16. Creativity for Problem Solvers

    DEFF Research Database (Denmark)

    Vidal, Rene Victor Valqui


    This paper presents some modern and interdisciplinary concepts about creativity and creative processes specially related to problem solving. Central publications related to the theme are briefly reviewed. Creative tools and approaches suitable to support problem solving are also presented. Finally......, the paper outlines the author’s experiences using creative tools and approaches to: Facilitation of problem solving processes, strategy development in organisations, design of optimisation systems for large scale and complex logistic systems, and creative design of software optimisation for complex non...

  17. Simon on problem solving

    DEFF Research Database (Denmark)

    Foss, Kirsten; Foss, Nicolai Juul


    as a general approach to problem solving. We apply these Simonian ideas to organisational issues, specifically new organisational forms. Specifically, Simonian ideas allow us to develop a morphology of new organisational forms and to point to some design problems that characterise these forms.......Two of Herbert Simon's best-known papers are 'The Architecture of Complexity' and 'The Structure of Ill-Structured Problems.' We discuss the neglected links between these two papers, highlighting the role of decomposition in the context of problems on which constraints have been imposed...

  18. Numerical problems in physics

    CERN Document Server

    Singh, Devraj


    Numerical Problems in Physics, Volume 1 is intended to serve the need of the students pursuing graduate and post graduate courses in universities with Physics and Materials Science as subject including those appearing in engineering, medical, and civil services entrance examinations. KEY FEATURES: * 29 chapters on Optics, Wave & Oscillations, Electromagnetic Field Theory, Solid State Physics & Modern Physics * 540 solved numerical problems of various universities and ompetitive examinations * 523 multiple choice questions for quick and clear understanding of subject matter * 567 unsolved numerical problems for grasping concepts of the various topic in Physics * 49 Figures for understanding problems and concept

  19. Art as metontological problem

    Directory of Open Access Journals (Sweden)

    Radovanović Saša Ž.


    Full Text Available The author explains the link between fundamental ontology and metontology in Heidegger's thought. In this context, he raises the question about art as a metontological problem. Then he goes to show that the problem of metontology stems from imanent transformation of fundamental ontology. In this sense, two aspects of the problem of existence assume relevance, namely, universality and radicalism. He draws the conclusion that metontology and art as its problem, as opposed to fundamental ontology, were not integrated into Heidegger's later thought.

  20. Known TCP Implementation Problems (United States)

    Paxson, Vern (Editor); Allman, Mark; Dawson, Scott; Fenner, William; Griner, Jim; Heavens, Ian; Lahey, K.; Semke, J.; Volz, B.


    This memo catalogs a number of known TCP implementation problems. The goal in doing so is to improve conditions in the existing Internet by enhancing the quality of current TCP/IP implementations. It is hoped that both performance and correctness issues can be resolved by making implementors aware of the problems and their solutions. In the long term, it is hoped that this will provide a reduction in unnecessary traffic on the network, the rate of connection failures due to protocol errors, and load on network servers due to time spent processing both unsuccessful connections and retransmitted data. This will help to ensure the stability of the global Internet. Each problem is defined as follows: Name of Problem The name associated with the problem. In this memo, the name is given as a subsection heading. Classification one or more problem categories for which the problem is classified: "congestion control", "performance", "reliability", "resource management". Description A definition of the problem, succinct but including necessary background material. Significance A brief summary of the sorts of environments for which the problem is significant.

  1. Shielding benchmark problems, (2)

    International Nuclear Information System (INIS)

    Tanaka, Shun-ichi; Sasamoto, Nobuo; Oka, Yoshiaki; Shin, Kazuo; Tada, Keiko.


    Shielding benchmark problems prepared by Working Group of Assessment of Shielding Experiments in the Research Committee on Shielding Design in the Atomic Energy Society of Japan were compiled by Shielding Laboratory in Japan Atomic Energy Research Institute. Fourteen shielding benchmark problems are presented newly in addition to twenty-one problems proposed already, for evaluating the calculational algorithm and accuracy of computer codes based on discrete ordinates method and Monte Carlo method and for evaluating the nuclear data used in codes. The present benchmark problems are principally for investigating the backscattering and the streaming of neutrons and gamma rays in two- and three-dimensional configurations. (author)

  2. Problems in baryon spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Capstick, S. [Florida State Univ., Tallahassee, FL (United States)


    Current issues and problems in the physics of ground- and excited-state baryons are considered, and are classified into those which should be resolved by CEBAF in its present form, and those which may require CEBAF to undergo an energy upgrade to 8 GeV or more. Recent theoretical developments designed to address these problems are outlined.

  3. Convex Congestion Network Problems

    NARCIS (Netherlands)

    Quant, M.; Reijnierse, J.H.


    This paper analyzes convex congestion network problems.It is shown that for network problems with convex congestion costs, an algorithm based on a shortest path algorithm, can be used to find an optimal network for any coalition. Furthermore an easy way of determining if a given network is optimal

  4. Reconfigurable layout problem

    NARCIS (Netherlands)

    Meng, G.; Heragu, S.S.; Heragu, S.S.; Zijm, Willem H.M.


    This paper addresses the reconfigurable layout problem, which differs from traditional, robust and dynamic layout problems mainly in two aspects: first, it assumes that production data are available only for the current and upcoming production period. Second, it considers queuing performance

  5. The Birthday Problem Revisited. (United States)

    Jones, Kevin S.


    Examines variations on the classic problem that asks for the fewest number of people so that the probability of two people having the same birthday is at least one-half. Extends the problem to consider the probability of a bridge player having the same hand in a lifetime. (MDH)

  6. Problems in quantum mechanics

    CERN Document Server

    Goldman, Iosif Ilich; Geilikman, B T


    This challenging book contains a comprehensive collection of problems in nonrelativistic quantum mechanics of varying degrees of difficulty. It features answers and completely worked-out solutions to each problem. Geared toward advanced undergraduates and graduate students, it provides an ideal adjunct to any textbook in quantum mechanics.

  7. The Problems of Dissection. (United States)

    Davis, Pat


    Describes some problems of classroom dissection including the cruelty that animals destined for the laboratory suffer. Discusses the multilevel approach that the National Anti-Vivisection Society (NAVS) has developed to address the problems of animal dissection such as offering a dissection hotline, exhibiting at science teacher conferences, and…

  8. Problem Solving and Reasoning. (United States)


    formed. The Understand program ( Rayes & Sisnon, 1974) is i computer simulation of the problem understanding process for puzzle-like problems like the...current in a wire connected to a battery and a metal rod, depending on the temperature differential of the bar , the internal resistance of the battery, and




  10. Fractional location problems

    NARCIS (Netherlands)

    A.I. Barros (Ana); J.B.G. Frenk (Hans); J.A.S. Gromicho (Joaquim)


    textabstractIn this paper we analyze some variants of the classical uncapacitated facility location problem with a ratio as an objective function. Using basic concepts and results of fractional programming, we identify a class of one-level fractional location problems which can be solved in

  11. The solar neutrino problem

    International Nuclear Information System (INIS)

    Roxburgh, I.W.


    The problems posed by the low flux of neutrinos from the sun detected by Davis and coworkers are reviewed. Several proposals have been advanced to resolve these problems and the more reasonable (in the author's opinion) are presented. Recent claims that the neutrino may have finite mass are also considered. (orig.)

  12. A Stochastic Employment Problem (United States)

    Wu, Teng


    The Stochastic Employment Problem(SEP) is a variation of the Stochastic Assignment Problem which analyzes the scenario that one assigns balls into boxes. Balls arrive sequentially with each one having a binary vector X = (X[subscript 1], X[subscript 2],...,X[subscript n]) attached, with the interpretation being that if X[subscript i] = 1 the ball…

  13. Managing Classroom Problems. (United States)

    Long, James D.

    Schools need to meet unique problems through the development of special classroom management techniques. Factors which contribute to classroom problems include lack of supervision at home, broken homes, economic deprivation, and a desire for peer attention. The educational atmosphere should encourage creativity for both the student and the…

  14. The solar neutrino problem

    Indian Academy of Sciences (India)

    The solar neutrino problem, the longstanding disagreement between the measured and predicted neutrino flux from the Sun, has moved from being a curiosity of solar physics to a research problem that now commands the attention of a large number of physicists who have at their disposal impressive experimental ...

  15. Inverse logarithmic potential problem

    CERN Document Server

    Cherednichenko, V G


    The Inverse and Ill-Posed Problems Series is a series of monographs publishing postgraduate level information on inverse and ill-posed problems for an international readership of professional scientists and researchers. The series aims to publish works which involve both theory and applications in, e.g., physics, medicine, geophysics, acoustics, electrodynamics, tomography, and ecology.

  16. Problem Solving and Learning (United States)

    Singh, Chandralekha


    One finding of cognitive research is that people do not automatically acquire usable knowledge by spending lots of time on task. Because students' knowledge hierarchy is more fragmented, "knowledge chunks" are smaller than those of experts. The limited capacity of short term memory makes the cognitive load high during problem solving tasks, leaving few cognitive resources available for meta-cognition. The abstract nature of the laws of physics and the chain of reasoning required to draw meaningful inferences makes these issues critical. In order to help students, it is crucial to consider the difficulty of a problem from the perspective of students. We are developing and evaluating interactive problem-solving tutorials to help students in the introductory physics courses learn effective problem-solving strategies while solidifying physics concepts. The self-paced tutorials can provide guidance and support for a variety of problem solving techniques, and opportunity for knowledge and skill acquisition.

  17. Structural Identification Problem

    Directory of Open Access Journals (Sweden)

    Suvorov Aleksei


    Full Text Available The identification problem of the existing structures though the Quasi-Newton and its modification, Trust region algorithms is discussed. For the structural problems, which could be represented by means of the mathematical modelling of the finite element code discussed method is extremely useful. The nonlinear minimization problem of the L2 norm for the structures with linear elastic behaviour is solved by using of the Optimization Toolbox of Matlab. The direct and inverse procedures for the composition of the desired function to minimize are illustrated for the spatial 3D truss structure as well as for the problem of plane finite elements. The truss identification problem is solved with 2 and 3 unknown parameters in order to compare the computational efforts and for the graphical purposes. The particular commands of the Matlab codes are present in this paper.

  18. Problems in equilibrium theory

    CERN Document Server

    Aliprantis, Charalambos D


    In studying General Equilibrium Theory the student must master first the theory and then apply it to solve problems. At the graduate level there is no book devoted exclusively to teaching problem solving. This book teaches for the first time the basic methods of proof and problem solving in General Equilibrium Theory. The problems cover the entire spectrum of difficulty; some are routine, some require a good grasp of the material involved, and some are exceptionally challenging. The book presents complete solutions to two hundred problems. In searching for the basic required techniques, the student will find a wealth of new material incorporated into the solutions. The student is challenged to produce solutions which are different from the ones presented in the book.

  19. The moment problem

    CERN Document Server

    Schmüdgen, Konrad


    This advanced textbook provides a comprehensive and unified account of the moment problem. It covers the classical one-dimensional theory and its multidimensional generalization, including modern methods and recent developments. In both the one-dimensional and multidimensional cases, the full and truncated moment problems are carefully treated separately. Fundamental concepts, results and methods are developed in detail and accompanied by numerous examples and exercises. Particular attention is given to powerful modern techniques such as real algebraic geometry and Hilbert space operators. A wide range of important aspects are covered, including the Nevanlinna parametrization for indeterminate moment problems, canonical and principal measures for truncated moment problems, the interplay between Positivstellensätze and moment problems on semi-algebraic sets, the fibre theorem, multidimensional determinacy theory, operator-theoretic approaches, and the existence theory and important special topics of multidime...

  20. The Guderley problem revisited

    Energy Technology Data Exchange (ETDEWEB)

    Ramsey, Scott D [Los Alamos National Laboratory; Kamm, James R [Los Alamos National Laboratory; Bolstad, John H [NON LANL


    The self-similar converging-diverging shock wave problem introduced by Guderley in 1942 has been the source of numerous investigations since its publication. In this paper, we review the simplifications and group invariance properties that lead to a self-similar formulation of this problem from the compressible flow equations for a polytropic gas. The complete solution to the self-similar problem reduces to two coupled nonlinear eigenvalue problems: the eigenvalue of the first is the so-called similarity exponent for the converging flow, and that of the second is a trajectory multiplier for the diverging regime. We provide a clear exposition concerning the reflected shock configuration. Additionally, we introduce a new approximation for the similarity exponent, which we compare with other estimates and numerically computed values. Lastly, we use the Guderley problem as the basis of a quantitative verification analysis of a cell-centered, finite volume, Eulerian compressible flow algorithm.

  1. Solved problems in electrochemistry

    International Nuclear Information System (INIS)

    Piron, D.L.


    This book presents calculated solutions to problems in fundamental and applied electrochemistry. It uses industrial data to illustrate scientific concepts and scientific knowledge to solve practical problems. It is subdivided into three parts. The first uses modern basic concepts, the second studies the scientific basis for electrode and electrolyte thermodynamics (including E-pH diagrams and the minimum energy involved in transformations) and the kinetics of rate processes (including the energy lost in heat and in parasite reactions). The third part treats larger problems in electrolysis and power generation, as well as in corrosion and its prevention. Each chapter includes three sections: the presentation of useful principles; some twenty problems with their solutions; and, a set of unsolved problems

  2. An imperfect bifurcation problem (United States)

    Descloux, J.

    The problem considered in the present investigation involves the motion of a beam rotating around an axis at constant angular velocity. It is assumed that the beam, in its rest position, does not coincide exactly with the axis. This case leads to an imperfect bifurcation problem. The current investigation has the objective to provide a numerical approximation regarding the conditions in the considered situation. A finite difference scheme is discussed, taking into account the classical two-points boundary value problem. Attention is given to the relations concerning perfect and imperfect bifurcations, a theorem with respect to the existence of solutions for the considered problem, and the proof of this theorem. The physical problem considered involves a satellite with an antenna.

  3. Problems in abstract algebra

    CERN Document Server

    Wadsworth, A R


    This is a book of problems in abstract algebra for strong undergraduates or beginning graduate students. It can be used as a supplement to a course or for self-study. The book provides more variety and more challenging problems than are found in most algebra textbooks. It is intended for students wanting to enrich their learning of mathematics by tackling problems that take some thought and effort to solve. The book contains problems on groups (including the Sylow Theorems, solvable groups, presentation of groups by generators and relations, and structure and duality for finite abelian groups); rings (including basic ideal theory and factorization in integral domains and Gauss's Theorem); linear algebra (emphasizing linear transformations, including canonical forms); and fields (including Galois theory). Hints to many problems are also included.

  4. Sleep problems in childhood. (United States)

    Adair, R H; Bauchner, H


    Sleep, like eating and toileting, is an individual physical requirement that changes with time as the child matures. Although much about a child's sleep is biologically determined, extrinsic factors, usually through the parents, also mold the child's sleep behavior. Normal sleep for a child is restful to the child and not excessively disruptive to others. Sleep problems interfere with the quality of the child's sleep and frustrate or frighten caretakers. Several sleep problems have their origins in normal sleep behavior from an earlier age. Some, the parasomnias, are caused by self-limited biologic diatheses. Many sleep problems have psychosocial triggers. Sleep disorders only rarely are a primary medical problem that is adequately treated with medication (e.g., narcolepsy). Good history-taking, often accompanied by diary-keeping, will usually identify the problem--the first step in effective treatment. Treatment of a sleep disorder in the pediatrician's office can start with educating caretakers about normative sleep for the age of the child and providing information regarding the cause and natural course of the problem. Treatment also may involve behavioral or psychological intervention or both, but medication is generally not indicated. When needed for short-term treatment, mild sedatives such as antihistamines are used most often. More serious sleep or behavioral problems should be acknowledged by the primary care pediatrician, followed by referral to an appropriate specialist. Inquiry into a child's sleep habits at each well-child visit, coupled with appropriate anticipatory guidance, could make an important contribution to the child and family by preventing problems with sleep and identifying sleep problems early in their evolution. Pediatricians and parents can work together to help children develop good sleep habits that fulfill the child's evolving sleep requirements within the context of the family's needs and expectations.

  5. Brauer type embedding problems

    CERN Document Server

    Ledet, Arne


    This monograph is concerned with Galois theoretical embedding problems of so-called Brauer type with a focus on 2-groups and on finding explicit criteria for solvability and explicit constructions of the solutions. The advantage of considering Brauer type embedding problems is their comparatively simple condition for solvability in the form of an obstruction in the Brauer group of the ground field. This book presupposes knowledge of classical Galois theory and the attendant algebra. Before considering questions of reducing the embedding problems and reformulating the solvability criteria, the

  6. The Linear Ordering Problem

    CERN Document Server

    Marti, Rafael


    Faced with the challenge of solving the hard optimization problems that abound in the real world, existing methods often encounter great difficulties. Important applications in business, engineering or economics cannot be tackled by the techniques that have formed the predominant focus of academic research throughout the past three decades. Exact and heuristic approaches are dramatically changing our ability to solve problems of practical significance and are extending the frontier of problems that can be handled effectively. This monograph details state-of-the-art optimization methods, both e

  7. Astronauts' menu problem. (United States)

    Lesso, W. G.; Kenyon, E.


    Consideration of the problems involved in choosing appropriate menus for astronauts carrying out SKYLAB missions lasting up to eight weeks. The problem of planning balanced menus on the basis of prepackaged food items within limitations on the intake of calories, protein, and certain elements is noted, as well as a number of other restrictions of both physical and arbitrary nature. The tailoring of a set of menus for each astronaut on the basis of subjective rankings of each food by the astronaut in terms of a 'measure of pleasure' is described, and a computer solution to this problem by means of a mixed integer programming code is presented.

  8. Infection dynamics on spatial small-world network models (United States)

    Iotti, Bryan; Antonioni, Alberto; Bullock, Seth; Darabos, Christian; Tomassini, Marco; Giacobini, Mario


    The study of complex networks, and in particular of social networks, has mostly concentrated on relational networks, abstracting the distance between nodes. Spatial networks are, however, extremely relevant in our daily lives, and a large body of research exists to show that the distances between nodes greatly influence the cost and probability of establishing and maintaining a link. A random geometric graph (RGG) is the main type of synthetic network model used to mimic the statistical properties and behavior of many social networks. We propose a model, called REDS, that extends energy-constrained RGGs to account for the synergic effect of sharing the cost of a link with our neighbors, as is observed in real relational networks. We apply both the standard Watts-Strogatz rewiring procedure and another method that conserves the degree distribution of the network. The second technique was developed to eliminate unwanted forms of spatial correlation between the degree of nodes that are affected by rewiring, limiting the effect on other properties such as clustering and assortativity. We analyze both the statistical properties of these two network types and their epidemiological behavior when used as a substrate for a standard susceptible-infected-susceptible compartmental model. We consider and discuss the differences in properties and behavior between RGGs and REDS as rewiring increases and as infection parameters are changed. We report considerable differences both between the network types and, in the case of REDS, between the two rewiring schemes. We conclude that REDS represent, with the application of these rewiring mechanisms, extremely useful and interesting tools in the study of social and epidemiological phenomena in synthetic complex networks.

  9. Problems in optics

    CERN Document Server

    Rousseau, Madeleine; Ter Haar, D


    This collection of problems and accompanying solutions provide the reader with a full introduction to physical optics. The subject coverage is fairly traditional, with chapters on interference and diffraction, and there is a general emphasis on spectroscopy.

  10. The Problem of Heroin (United States)

    Wilson, James Q.; And Others


    Argues that most of the underlying assumptions of presently recommended solutions to the problem of heroin addiction are unreasonable, unwarranted, or at least open to more than one interpretation. (DM)

  11. Problems of research politics

    International Nuclear Information System (INIS)

    Luest, R.


    The development in the FRG is portrayed. Illustrated by a particular example, the problems of basic research and of the scientists are presented looking back, looking at the present, and into the future. (WB) [de

  12. Gait or Walking Problems (United States)

    Gait or Walking Problems the basic facts multiple sclerosis Many people with MS will experience difficulty with walking, which is also called ambulation. The term “gait” refers more specifically to the manner or pattern ...

  13. Mouth Problems and HIV (United States)

    ... teeth (periodontitis), canker sores, oral warts, fever blisters, oral candidiasis (thrush), hairy leukoplakia (which causes a rough, white patch on the tongue), and dental caries. Read More Publications Cover image Mouth Problems + HIV Publication files Download Language English PDF — ...

  14. The cosmological constant problem

    International Nuclear Information System (INIS)

    Dolgov, A.D.


    A review of the cosmological term problem is presented. Baby universe model and the compensating field model are discussed. The importance of more accurate data on the Hubble constant and the Universe age is stressed. 18 refs

  15. Creativity and Problem Solving

    DEFF Research Database (Denmark)

    Vidal, Rene Victor Valqui


    This paper presents some modern and interdisciplinary concepts about creativity and creative processes of special relevance for Operational Research workers. Central publications in the area Creativity-Operational Research are shortly reviewed. Some creative tools and the Creative Problem Solving...

  16. Sleep Problems and ADHD

    Directory of Open Access Journals (Sweden)

    J Gordon Millichap


    Full Text Available The prevalence of sleep problems and their associations with quality of life (QOL, school attendance, and family impacts in children with ADHD were determined in a study at Royal Children's Hospital, University of Melbourne, Australia.

  17. Women and sexual problems (United States)

    ... Illnesses can cause problems with sex. Illnesses like cancer, bladder or bowel diseases, arthritis, and headaches may cause ... used during any medical emergency or for the diagnosis or treatment of any medical condition. A licensed ...

  18. Pelvic Support Problems (United States)

    ... problems may find that increasing the amount of fiber in their diets prevents constipation and straining during bowel movements. Sometimes a medication that softens stools is prescribed. If a woman is overweight or obese, weight loss can help improve her ...

  19. Challenging problems in geometry

    CERN Document Server

    Posamentier, Alfred S


    Collection of nearly 200 unusual problems dealing with congruence and parallelism, the Pythagorean theorem, circles, area relationships, Ptolemy and the cyclic quadrilateral, collinearity and concurrency and more. Arranged in order of difficulty. Detailed solutions.

  20. Open problems in mathematics

    CERN Document Server

    Nash, Jr, John Forbes


    The goal in putting together this unique compilation was to present the current status of the solutions to some of the most essential open problems in pure and applied mathematics. Emphasis is also given to problems in interdisciplinary research for which mathematics plays a key role. This volume comprises highly selected contributions by some of the most eminent mathematicians in the international mathematical community on longstanding problems in very active domains of mathematical research. A joint preface by the two volume editors is followed by a personal farewell to John F. Nash, Jr. written by Michael Th. Rassias. An introduction by Mikhail Gromov highlights some of Nash’s legendary mathematical achievements. The treatment in this book includes open problems in the following fields: algebraic geometry, number theory, analysis, discrete mathematics, PDEs, differential geometry, topology, K-theory, game theory, fluid mechanics, dynamical systems and ergodic theory, cryptography, theoretical computer sc...

  1. Teaching Creative Problem Solving. (United States)

    Christensen, Kip W.; Martin, Loren


    Interpersonal and cognitive skills, adaptability, and critical thinking can be developed through problem solving and cooperative learning in technology education. These skills have been identified as significant needs of the workplace as well as for functioning in society. (SK)

  2. The Elder Problem

    Directory of Open Access Journals (Sweden)

    John W. Elder


    Full Text Available This paper presents an autobiographical and biographical historical account of the genesis, evolution and resolution of the Elder Problem. It begins with John W. Elder and his autobiographical story leading to his groundbreaking work on natural convection at Cambridge in the 1960’s. His seminal work published in the Journal of Fluid Mechanics in 1967 became the basis for the modern benchmark of variable density flow simulators that we know today as “The Elder Problem”. There have been well known and major challenges with the Elder Problem model benchmark—notably the multiple solutions that were ultimately uncovered using different numerical models. Most recently, it has been shown that the multiple solutions are indeed physically realistic bifurcation solutions to the Elder Problem and not numerically spurious artefacts. The quandary of the Elder Problem has now been solved—a major scientific breakthrough for fluid mechanics and for numerical modelling. This paper—records, reflections, reminiscences, stories and anecdotes—is an historical autobiographical and biographical memoir. It is the personal story of the Elder Problem told by some of the key scientists who established and solved the Elder Problem. 2017 marks the 50 year anniversary of the classical work by John W. Elder published in Journal of Fluid Mechanics in 1967. This set the stage for this scientific story over some five decades. This paper is a celebration and commemoration of the life and times of John W. Elder, the problem named in his honour, and some of the key scientists who worked on, and ultimately solved, it.

  3. The Steiner tree problem

    CERN Document Server

    Hwang, FK; Winter, P


    The Steiner problem asks for a shortest network which spans a given set of points. Minimum spanning networks have been well-studied when all connections are required to be between the given points. The novelty of the Steiner tree problem is that new auxiliary points can be introduced between the original points so that a spanning network of all the points will be shorter than otherwise possible. These new points are called Steiner points - locating them has proved problematic and research has diverged along many different avenues. This volume is devoted to the assimilation of the rich field of intriguing analyses and the consolidation of the fragments. A section has been given to each of the three major areas of interest which have emerged. The first concerns the Euclidean Steiner Problem, historically the original Steiner tree problem proposed by Jarník and Kössler in 1934. The second deals with the Steiner Problem in Networks, which was propounded independently by Hakimi and Levin and has enjoyed the most...

  4. Solving Environmental Problems

    DEFF Research Database (Denmark)

    Ørding Olsen, Anders; Sofka, Wolfgang; Grimpe, Christoph


    dispersed. Hence, firms need to collaborate. We shed new light on collaborative search strategies led by firms in general and for solving environmental problems in particular. Both topics are largely absent in the extant open innovation literature. Using data from the European Seventh Framework Program...... for Research and Technological Development (FP7), our results indicate that the problem-solving potential of a search strategy increases with the diversity of existing knowledge of the partners in a consortium and with the experience of the partners involved. Moreover, we identify a substantial negative effect......Recent innovation and strategy research emphasizes the importance of firm’s search for external knowledge to improve innovation performance. We focus on such search strategies within the domain of sustainable innovation in which problems are inherently complex and the relevant knowledge is widely...

  5. Computational problems in engineering

    CERN Document Server

    Mladenov, Valeri


    This book provides readers with modern computational techniques for solving variety of problems from electrical, mechanical, civil and chemical engineering. Mathematical methods are presented in a unified manner, so they can be applied consistently to problems in applied electromagnetics, strength of materials, fluid mechanics, heat and mass transfer, environmental engineering, biomedical engineering, signal processing, automatic control and more.   • Features contributions from distinguished researchers on significant aspects of current numerical methods and computational mathematics; • Presents actual results and innovative methods that provide numerical solutions, while minimizing computing times; • Includes new and advanced methods and modern variations of known techniques that can solve difficult scientific problems efficiently.  

  6. Appreciative Problem Solving

    DEFF Research Database (Denmark)

    Hansen, David


    Many industrial production work systems have increased in complexity, and their new business model scompete on innovation, rather than low cost.At a medical device production facility committed to Lean Production, a research project was carried out to use Appreciative Inquiry to better engage...... employee strengths in continuou simprovements of the work system. The research question was: “How can Lean problem solving and Appreciative Inquiry be combined for optimized work system innovation?” The research project was carried out as a co-creation process with close cooperation between researcher...... to work system innovation and discusses how Appreciative Inquiry, Problem Solving, and the combination ‘Appreciative Problem Solving’ can be used to optimize continuous work system innovation.These findings add to the theoretical foundation of the emerging field of Strength-based Lean....

  7. Problem Based Learning

    DEFF Research Database (Denmark)

    de Graaff, Erik; Guerra, Aida

    Problem-Based Learning (PBL) is an innovative method to organize the learning process in such a way that the students actively engage in finding answers by themselves. During the past 40 years PBL has evolved and diversified resulting in a multitude in variations in models and practices. However......, the key principles remain the same everywhere. Graaff & Kolmos (2003) identify the main PBL principles as follows: 1. Problem orientation 2. Project organization through teams or group work 3. Participant-directed 4. Experiental learning 5. Activity-based learning 6. Interdisciplinary learning and 7...... in Engineering Education. In answer to the requests for visits the Aalborg Centre for Problem Based Learning in Engineering Science and Sustainability under the auspices of UNESCO (UCPBL) a two days programme for visitors is offered two times a year. The workshop is an introduction workshop to the Aalborg PBL...

  8. Solved problems in electromagnetics

    CERN Document Server

    Salazar Bloise, Félix; Bayón Rojo, Ana; Gascón Latasa, Francisco


    This book presents the fundamental concepts of electromagnetism through problems with a brief theoretical introduction at the beginning of each chapter. The present book has a strong  didactic character. It explains all the mathematical steps and the theoretical concepts connected with the development of the problem. It guides the reader to understand the employed procedures to learn to solve the exercises independently. The exercises are structured in a similar way: The chapters begin with easy problems increasing progressively in the level of difficulty. This book is written for students of physics and engineering in the framework of the new European Plans of Study for Bachelor and Master and also for tutors and lecturers. .

  9. Atomic policies: history, problems

    International Nuclear Information System (INIS)

    Galvan, Cesare Giuseppe.


    Two kinds of problems follow from the development of nuclear technology: its use in (diversion to) armaments, and its dangers for the population. Both arise as social phenomena: technology can be diverted to military aims; and installations require specific measures in order not to expose human life to danger. The diffusion of this technology required a series of tentative solutions for such problems. Its history constitutes our first part. The second part aims at understanding the dynamics, which led to the diffusion of such a technology in the capitalist world. The concept of subsumption (especially of its realization) is suited to interpret the meanings of the social interests, which led content ro this diffusion. Subsumption is found between labor and capital, but also between society and state. At both levels, it shows that there was some social meaning in the diffusion of nuclear technology notwithstanding its problems. 590 refs

  10. Translating a wicked problem

    DEFF Research Database (Denmark)

    Tietjen, Anne; Jørgensen, Gertrud


    In a time of increasing globalisation and urbanisation, shrinking peripheral rural areas have become a truly wicked planning problem in many European countries. Although a problem can be easily perceived and measured by various indicators, the precise definition of the problem is problematic. Based......, place-based and project-oriented process directed at concrete physical outcomes. We frame strategic planning as a translation process where the interaction between human and non-human actors translates a unique, complex and contested situation into an innovated situation. We find that local physical......-understandings, increased social capital, and follow-up projects initiated beyond the actual planning process. We conclude that local physical projects, when conceived in a collaborative and strategic manner, can contribute to sustainable adaptation to rural shrinkage....

  11. Sleep problems in children. (United States)

    Hannan, Katrina; Hiscock, Harriet


    Childhood sleep problems are common, and frequently reduce the wellbeing and functioning of both child and family. The majority of childhood sleep problems are behavioural in origin. This article outlines the aetiology and features of sleep difficulties in children, from infants to teenagers, and provides a corresponding 'toolkit' of evidence-based behavioural management strategies. Childhood behavioural sleep problems manifest across age groups as various forms of difficulty initiating and/or maintaining sleep. These difficulties are often amenable to home-based behavioural interventions, which can be taught to parents and, de-pending on their developmental stage, the child or adolescent. Sustaining the intervention for sufficient sleep duration can be challenging for families. Community health practitioners play a central role in tailoring the explanation of management strategies to families and children or adolescents. Sleep diaries and education materials from evidence-based websites can assist the practitioner and family in achieving successful diagnosis and treatment.

  12. Spent fuel transportation problems

    International Nuclear Information System (INIS)

    Kondrat'ev, A.N.; Kosarev, Yu.A.; Yulikov, E.A.


    In this paper, problems of transportation of nuclear spent fuel to reprocessing plants are discussed. The solutions proposed are directed toward the achievement of the transportation as economic and safe as possible. The increase of the nuclear power plants number in the USSR and the great distances between these plants and the reprocessing plants involve an intensification of the spent fuel transportation. Higher burnup and holdup time reduction cause the necessity of more bulky casks. In this connection, the economic problems become still more important. One of the ways of the problem solution is the development of rational and cheap cask designs. Also, the enforcement in the world of the environmental and personnel health protection requires to increase the transportation reliability and safety. The paper summarizes safe transportation rules with clarifying the following questions: the increase of the transport unit quantity of the spent fuel; rational shipment organization that minimizes vehicle turnover cycle duration; development of the reliable calculation methods to determine strength, thermal conditions and nuclear safety of transport packaging as applied to the vehicles of high capacity; maximum unification of vehicles, calculation methods and documents; and cask testing on models and in pilot scale on specific test rigs to assure that they meet the international safe fuel shipment rules. Besides, some considerations on the choice and use of structural materials for casks are given, and problems of manufacturing such casks from uranium and lead are considered, as well as problems of the development of fireproof shells, control instrumentation, vehicles decontamination, etc. All the problems are considered from the point of view of normal and accidental shipment conditions. Conclusions are presented [ru

  13. Integrating Multimedia and Physics Problems (United States)

    Titus, Aaron P.


    Although expert problem solvers typically use pictorial representations when solving problems, novices tend to proceed from the given problem statement to a mathematical solution without first developing a visual representation of the problem. For this reason, multimedia may be an effective tool to enhance students' success at solving problems. However, merely presenting a video of motion described in a problem is not necessarily the most effective method as was found in a recent study of students' responses on Web-based homework questions. Rather, multimedia-focused problems, where data relevant to solving the problem is embedded in a video or animation, may be the best use of multimedia in problem solving. Examples of multimedia-enhanced problems and multimedia-focused problems will be demonstrated, and their differences from "traditional" problems will be highlighted. Recommendations on the use of multimedia with problem solving and preliminary data on students' success at solving these problems will be discussed.

  14. Electric circuits problem solver

    CERN Document Server

    REA, Editors of


    Each Problem Solver is an insightful and essential study and solution guide chock-full of clear, concise problem-solving gems. All your questions can be found in one convenient source from one of the most trusted names in reference solution guides. More useful, more practical, and more informative, these study aids are the best review books and textbook companions available. Nothing remotely as comprehensive or as helpful exists in their subject anywhere. Perfect for undergraduate and graduate studies.Here in this highly useful reference is the finest overview of electric circuits currently av

  15. Problems in quantum mechanics

    CERN Document Server

    Kogan, V.I; Gersch, Harold


    Written by a pair of distinguished Soviet mathematicians, this compilation presents 160 lucidly expressed problems in nonrelativistic quantum mechanics plus completely worked-out solutions. Some were drawn from the authors' courses at the Moscow Institute of Engineering, but most were prepared especially for this book. A high-level supplement rather than a primary text, it constitutes a masterful complement to advanced undergraduate and graduate texts and courses in quantum mechanics.The mathematics employed in the proofs of the problems-asymptotic expansions of functions, Green's functions, u

  16. The Problem Revisited

    DEFF Research Database (Denmark)

    Ovesen, Nis


    Problem-based learning (PBL) is becoming increasingly popular in design educations, but how is it taught and practiced? This paper presents a case study of a three-day workshop that has the purpose of introducing PBL to design students. A theoretical background on PBL and problems in design is es...... is established and is backing up the case study. The study shows that design engineering and architectural students without experience in PBL in general finds the approach to be beneficial when working on a design challenge in a student team....

  17. Problem Based Game Design

    DEFF Research Database (Denmark)

    Reng, Lars; Schoenau-Fog, Henrik


    At Aalborg University’s department of Medialogy, we are utilizing the Problem Based Learning method to encourage students to solve game design problems by pushing the boundaries and designing innovative games. This paper is concerned with describing this method, how students employ it in various...... projects and how they learn to analyse, design, and develop for innovation by using it. We will present various cases to exemplify the approach and focus on how the method engages students and aspires for innovation in digital entertainment and games....

  18. Classic Problems of Probability

    CERN Document Server

    Gorroochurn, Prakash


    "A great book, one that I will certainly add to my personal library."—Paul J. Nahin, Professor Emeritus of Electrical Engineering, University of New Hampshire Classic Problems of Probability presents a lively account of the most intriguing aspects of statistics. The book features a large collection of more than thirty classic probability problems which have been carefully selected for their interesting history, the way they have shaped the field, and their counterintuitive nature. From Cardano's 1564 Games of Chance to Jacob Bernoulli's 1713 Golden Theorem to Parrondo's 1996 Perplexin

  19. Calculus problems and solutions

    CERN Document Server

    Ginzburg, Abraham


    Ideal for self-instruction as well as for classroom use, this text helps students improve their understanding and problem-solving skills in analysis, analytic geometry, and higher algebra. More than 1,200 problems appear in the text, with concise explanations of the basic notions and theorems to be used in their solution. Many are followed by complete answers; solutions for the others appear at the end of the book. Topics include sequences, functions of a single variable, limit of a function, differential calculus for functions of a single variable, fundamental theorems and applications of dif

  20. Quantization for brachistochrone problem (United States)

    Yucel, M. B.; Unal, N.


    The brachistochrone curve corresponds to the minimization of the time functional. In this paper we discuss the dynamics of a massive particle, which moves classically on the brachistochrone curve under the potential V=- mgy. We derive the Lagrangian and the Hamiltonian of the particle and show that this problem corresponds to the particle in an infinite wall with a harmonic oscillator potential and the solutions of Schrödinger’s equation are confluent hypergeometric functions. We also discuss the periodic potential problem for the brachistochrones and obtain the band structure of Kronig-Penney model for the particle with positive energy in a certain limit.

  1. The inverse brachistochrone problem (United States)

    Gomez, Raul; Gomez, Sandra; Marquina, Vivianne


    Ever since Johan Bernoulli^1 challenge the mathematicians of his time with the problem of finding the least time trajectory (brachistochrone) of a body moving in the uniform gravitational field between two points not in the same vertical line, many papers have been published relating different facets of this problem. In this work we use simplified forms of Euler equations to find the expression that defines the brachistochrone associated with an arbitrary potential energy function and also the expression that determines the potential energy function for which an arbitrary curve would be a brachistochrone, ^1J. Bernoulli. Problema novum ad cujus solutionem mathematice invitantur. Acta Eruditorum Lipsiae, June 1696.

  2. Advanced calculus problem solver

    CERN Document Server

    REA, Editors of


    Each Problem Solver is an insightful and essential study and solution guide chock-full of clear, concise problem-solving gems. All your questions can be found in one convenient source from one of the most trusted names in reference solution guides. More useful, more practical, and more informative, these study aids are the best review books and textbook companions available. Nothing remotely as comprehensive or as helpful exists in their subject anywhere. Perfect for undergraduate and graduate studies.Here in this highly useful reference is the finest overview of advanced calculus currently av

  3. Problems over Information Systems

    KAUST Repository

    Chikalov, Igor


    The problems of estimation of the minimum average time complexity of decision trees and design of efficient algorithms are complex in general case. The upper bounds described in Chap. 2.4.3 can not be applied directly due to large computational complexity of the parameter M(z). Under reasonable assumptions about the relation of P and NP, there are no polynomial time algorithms with good approximation ratio [12, 32]. One of the possible solutions is to consider particular classes of problems and improve the existing results using characteristics of the considered classes. © Springer-Verlag Berlin Heidelberg 2011.

  4. Matrices in Engineering Problems

    CERN Document Server

    Tobias, Marvin


    This book is intended as an undergraduate text introducing matrix methods as they relate to engineering problems. It begins with the fundamentals of mathematics of matrices and determinants. Matrix inversion is discussed, with an introduction of the well known reduction methods. Equation sets are viewed as vector transformations, and the conditions of their solvability are explored. Orthogonal matrices are introduced with examples showing application to many problems requiring three dimensional thinking. The angular velocity matrix is shown to emerge from the differentiation of the 3-D orthogo

  5. Catastrophes control problem

    International Nuclear Information System (INIS)

    Velichenko, V.V.


    The problem of catastrophe control is discussed. Catastrophe control aims to withdraw responsible engineering constructions out of the catastrophe. The mathematical framework of catastrophes control systems is constructed. It determines the principles of systems filling by the concrete physical contents and, simultaneously, permits to employ modern control methods for the synthesis of optimal withdrawal strategy for protected objects

  6. The Secretary Problem

    Indian Academy of Sciences (India)

    Consider now the probability that a particular selection strategy gets the right candidate. If we can get these probabilities for all the possible strategies (a large set, no doubt!) then possibly we may get hold of the strategy with the highest probability and declare that as the 'best' strategy. 1 For obvious reasons this problem is ...




  8. The Bycatch Problem

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 12; Issue 5. The Bycatch Problem - Effects of Commercial Fisheries on Non-Target Species in India. Aaron Savio Lobo. General Article Volume 12 Issue 5 May 2007 pp 60-70 ...

  9. Hip Problems in Infants (United States)

    ... A hip problem in infants is known as developmental dysplasia of the hip (DDH). It is when the ball of the ... later in life? Resources International Hip Dysplasia Institute, Developmental Dysplasia of the Hip (DDH) International Hip Dysplasia Institute, Hip-Healthy Swaddling ...

  10. The Class Number Problem

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 7. The Class Number Problem - An Introduction to Algebraic Number Theory. Rajat Tandon. General ... Author Affiliations. Rajat Tandon1. Department of Mathematics, University of Hyderabad, Central University P.O., Hyderabad 500 046, India ...

  11. The Class Number Problem

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 6. The Class Number Problem - Binary Quadratic Forms. Rajat Tandon. General Article Volume 3 Issue ... Author Affiliations. Rajat Tandon1. Department of Mathematics, University of Hyderabad, Central University P.O. Hyderabad 500 046. India ...

  12. The Problem of Consciousness. (United States)

    Crick, Francis; Koch, Christof


    Discusses approaches to the problem presented in understanding consciousness as a yet undiscovered process of interacting neuron activity. Presents the historical context of research in the area of human awareness and identifies research necessary to scientifically explain how the brain relates to the mind. (MCO)

  13. Metacognitions in problem gambling. (United States)

    Lindberg, Annika; Fernie, Bruce A; Spada, Marcantonio M


    Problem gambling is heterogeneous in nature, ranging in severity from occasional but problematic gambling episodes, to extreme, impulsive and pervasive gambling behaviour. Problem gambling may be accompanied by a sense of impaired control and can give rise to financial, interpersonal, legal and vocational costs for the sufferer, their families and society. This study investigated the relationship among metacognitions, anxiety, depression and gambling in a sample of problem gamblers. A total of 91 individuals attending gambling treatment services completed a battery of self-report instruments that consisted of the Metacognitions Questionnaire 30 (MCQ-30), the Hospital Anxiety and Depression Scale (HADS) and the South Oaks Gambling Scale (SOGS). Correlation analyses showed that anxiety, depression and metacognitions were positively and significantly correlated with both gambling consequences and behaviour. Hierarchical regression analyses indicated that two metacognitive constructs (negative beliefs about thoughts concerning uncontrollability and danger and beliefs about the need to control thoughts) predicted gambling behaviour independently of anxiety and depression. These findings are consistent with the hypothesis that metacognitions play a role in problem gambling.

  14. Human Population Problems (United States)

    Emmel, Thomas C.; Sligh, Michael M.


    Asserts that overpopulation is the most pressing world problem. Topics discussed include population control in primitive societies, population growth and control in modern societies, methods of motivational population control, consequences of no population control, and mass famines during the 1970's in underdeveloped countries. Cities 33…

  15. The Birthday Problem Explained. (United States)

    Johnson, John M.


    Describes a classroom problem of probability as follows: How many people do you need in a group to ensure that the probability of at least two of them having the same birthday is greater than one-half? Answer: 23. The probability principles needed are simple enough to be accessible to advanced high school students. (PVD)

  16. Problem-based learning

    NARCIS (Netherlands)

    Loyens, Sofie; Kirschner, Paul A.; Paas, Fred


    Loyens, S. M. M., Kirschner, P. A., & Paas, F. (2011). Problem-based learning. In S. Graham (Editor-in-Chief), A. Bus, S. Major, & L. Swanson (Associate Editors), APA educational psychology handbook: Vol. 3. Application to learning and teaching (pp. 403-425). Washington, DC: American Psychological

  17. The Class Number Problem

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 7. The Class Number Problem - An Introduction to Algebraic Number Theory. Rajat Tandon. General Article Volume 3 Issue 7 July 1998 pp 28-37. Fulltext. Click here to view fulltext PDF. Permanent link:

  18. Solving Problems through Circles (United States)

    Grahamslaw, Laura; Henson, Lisa H.


    Several problem-solving interventions that utilise a "circle" approach have been applied within the field of educational psychology, for example, Circle Time, Circle of Friends, Sharing Circles, Circle of Adults and Solution Circles. This research explored two interventions, Solution Circles and Circle of Adults, and used thematic…

  19. Unfolding a Problem (United States)

    Currier, Sarah Cox


    In this article, Sarah Currier, a math specialist at Elizabeth Hall International School in Minnesota, describes how she used origami in a deliberate manner to teach content. She shares how she uses paper folding to teach mathematical concepts, reinforce vocabulary, and as a problem-solving model. She also offers ideas for using origami in other…

  20. The Three Colour Problem

    Indian Academy of Sciences (India)

    problem. This merely states a fact that any six-year old armed with crayons has long suspected - it is possible to colour any map in the family atlas with only four colours so that no two neighbouring regions have the same colour. Mathematicians have this habit of being precise, and they define a map to be a partition of some ...

  1. Problems in photoradiation effects

    International Nuclear Information System (INIS)

    Milinchuk, V.K.


    This paper discusses the most interesting photoradiation effects observed in recent years and directs attention to problems whose solution has a bearing on progress in photoradiation chemistry, and which also are significant for divisions of modern physical chemistry such as the kinetics and mechanisms of elementary processes in solid organic materials, the radiation resistance of organic materials, and aging in polymers

  2. Free discontinuity problems

    CERN Document Server

    Pratelli, Aldo


    This book presents a series of lectures on three of the best known examples of free discontinuity problems: the Mumford-Shah model for image segmentation, a variational model for the epitaxial growth of thin films, and the sharp interface limit of the Ohta-Kawasaki model for pattern formation in dyblock copolymers.

  3. The Class Number Problem

    Indian Academy of Sciences (India)

    The Class Number Problem. 2. An Introduction to Algebraic Number Theory. Rajat Tandon received his PhD from Yale. University, USA. After an initial period as a visiting post-doctoral fellow at. TIFR, he joined the faculty of the North. Eastern Hill University, where he taught for a few years. For about two decades now, he ...

  4. Filter and Passband Problems (United States)

    Young, A. T.


    Problems associated with achieving precision in photometric measurements of stars are examined. The thermal stabilization of glass and interference filters and the determination of correct analytic representations of bandwidth effects in data reduction are particularly discussed. Spectral sampling requirements are also addressed.

  5. Children Solve Problems. (United States)

    De Bono, Edward

    A group of children were presented with several tasks, including the invention of a sleep machine and a machine to weigh elephants. The tasks were chosen to involve the children in coping with problems of a distinct character. A study of the children's drawings and interpretations shows that children's thinking ability is not very different from…

  6. Random eigenvalue problems revisited

    Indian Academy of Sciences (India)

    eigenvalue problems arising in engineering systems is dominated by perturbation methods. These methods work ... eigenvalues are presented and their limitations in the context of engineering dynamic systems have been ...... ment of Civil Engineering, Indian Institute of Science, Bangalore (eds) K S Jagadish, R N Iyengar.

  7. A Geometric Dissection Problem

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 7; Issue 7. A Geometric Dissection Problem. M N Deshpande. Think It Over Volume 7 Issue 7 July 2002 pp 91-91. Fulltext. Click here to view fulltext PDF. Permanent link: Author Affiliations.

  8. Environmental Health Problems. (United States)

    Environmental Health Service (DHEW/PHS), Rockville, MD.

    Aimed at a society which is forced to make decisions relative to their total environment, this pamphlet discusses a few of the problems associated with restoring and maintaining an environmental relationship conducive to the health and well-being of man. The topics covered include: air pollution, noise, solid waste, the urban environment, drinking…

  9. Random eigenvalue problems revisited

    Indian Academy of Sciences (India)

    The description of real-life engineering structural systems is associated with some amount of uncertainty in specifying material properties, geometric parameters, boundary conditions and applied loads. In the context of structural dynamics it is necessary to consider random eigenvalue problems in order to account for these ...

  10. Can Learning Collaboratives Support Implementation by Rewiring Professional Networks? (United States)

    Bunger, Alicia C; Hanson, Rochelle F; Doogan, Nathan J; Powell, Byron J; Cao, Yiwen; Dunn, Jerry


    This study examined how a learning collaborative focusing on trauma-focused CBT (TF-CBT) impacted advice-seeking patterns between clinicians and three key learning sources: (1) training experts who share technical knowledge about TF-CBT, (2) peers from other participating organizations who share their implementation experiences, and (3) colleagues from their own agency who provide social and professional support. Based on surveys administered to 132 clinicians from 32 agencies, participants' professional networks changed slightly over time by forming new advice-seeking relationships with training experts. While small, these changes at the clinician-level yielded substantial changes in the structure of the regional advice network.

  11. Can Learning Collaboratives Support Implementation By Rewiring Professional Networks? (United States)

    Hanson, Rochelle F.; Doogan, Nathan J.; Powell, Byron J.; Cao, Yiwen; Dunn, Jerry


    This study examined how a learning collaborative focusing on Trauma-Focused CBT (TF-CBT) impacted advice-seeking patterns between clinicians and three key learning sources: (1) training experts who share technical knowledge about TF-CBT, (2) peers from other participating organizations who share their implementation experiences, and (3) colleagues from their own agency who provide social and professional support. Based on surveys administered to 132 clinicians from 32 agencies, participants’ professional networks changed slightly over time by forming new advice-seeking relationships with training experts. While small, these changes at the clinician-level yielded substantial changes in the structure of the regional advice network. PMID:25542237

  12. Rewired RNAi-mediated genome surveillance in house dust mites (United States)

    Klimov, Pavel; Flynt, Alex Sutton


    House dust mites are common pests with an unusual evolutionary history, being descendants of a parasitic ancestor. Transition to parasitism is frequently accompanied by genome rearrangements, possibly to accommodate the genetic change needed to access new ecology. Transposable element (TE) activity is a source of genomic instability that can trigger large-scale genomic alterations. Eukaryotes have multiple transposon control mechanisms, one of which is RNA interference (RNAi). Investigation of the dust mite genome failed to identify a major RNAi pathway: the Piwi-associated RNA (piRNA) pathway, which has been replaced by a novel small-interfering RNA (siRNA)-like pathway. Co-opting of piRNA function by dust mite siRNAs is extensive, including establishment of TE control master loci that produce siRNAs. Interestingly, other members of the Acari have piRNAs indicating loss of this mechanism in dust mites is a recent event. Flux of RNAi-mediated control of TEs highlights the unusual arc of dust mite evolution. PMID:29377900

  13. Rewiring Riboswitches to Create New Genetic Circuits in Bacteria. (United States)

    Robinson, C J; Medina-Stacey, D; Wu, M-C; Vincent, H A; Micklefield, J


    Riboswitches are RNA elements that control the expression of genes through a variety of mechanisms in response to the specific binding of small-molecule ligands. Since their discovery, riboswitches have shown promise for the artificial control of transcription or translation of target genes, be it for industrial biotechnology, protein expression, metabolic engineering, antimicrobial target validation, or gene function discovery. However, natural riboswitches are often unsuitable for these purposes due to their regulation by small molecules which are already present within the cell. For this reason, research has focused on creating riboswitches that respond to alternative biologically inert ligands or to molecules which are of interest for biosensing. Here we present methods for the development of artificial riboswitches in Gram-negative and Gram-positive bacteria. These methods are based on reengineering natural aptamers to change their ligand specificity toward molecules which do not bind the original aptamer (ie, that are orthogonal to the original). The first approach involves targeted mutagenesis of native riboswitches to change their specificity toward rationally designed synthetic ligand analogs. The second approach involves the fusion of previously validated orthogonal aptamers with native expression platforms to create novel chimeric riboswitches for the microbial target. We establish the applicability of these methods both for the control of exogenous genes as well as for the control of native genes. © 2016 Elsevier Inc. All rights reserved.

  14. Rewired RNAi-mediated genome surveillance in house dust mites. (United States)

    Mondal, Mosharrof; Klimov, Pavel; Flynt, Alex Sutton


    House dust mites are common pests with an unusual evolutionary history, being descendants of a parasitic ancestor. Transition to parasitism is frequently accompanied by genome rearrangements, possibly to accommodate the genetic change needed to access new ecology. Transposable element (TE) activity is a source of genomic instability that can trigger large-scale genomic alterations. Eukaryotes have multiple transposon control mechanisms, one of which is RNA interference (RNAi). Investigation of the dust mite genome failed to identify a major RNAi pathway: the Piwi-associated RNA (piRNA) pathway, which has been replaced by a novel small-interfering RNA (siRNA)-like pathway. Co-opting of piRNA function by dust mite siRNAs is extensive, including establishment of TE control master loci that produce siRNAs. Interestingly, other members of the Acari have piRNAs indicating loss of this mechanism in dust mites is a recent event. Flux of RNAi-mediated control of TEs highlights the unusual arc of dust mite evolution.

  15. Rewired RNAi-mediated genome surveillance in house dust mites.

    Directory of Open Access Journals (Sweden)

    Mosharrof Mondal


    Full Text Available House dust mites are common pests with an unusual evolutionary history, being descendants of a parasitic ancestor. Transition to parasitism is frequently accompanied by genome rearrangements, possibly to accommodate the genetic change needed to access new ecology. Transposable element (TE activity is a source of genomic instability that can trigger large-scale genomic alterations. Eukaryotes have multiple transposon control mechanisms, one of which is RNA interference (RNAi. Investigation of the dust mite genome failed to identify a major RNAi pathway: the Piwi-associated RNA (piRNA pathway, which has been replaced by a novel small-interfering RNA (siRNA-like pathway. Co-opting of piRNA function by dust mite siRNAs is extensive, including establishment of TE control master loci that produce siRNAs. Interestingly, other members of the Acari have piRNAs indicating loss of this mechanism in dust mites is a recent event. Flux of RNAi-mediated control of TEs highlights the unusual arc of dust mite evolution.

  16. Rewiring hydrogenase-dependent redox circuits in cyanobacteria (United States)

    Ducat, Daniel C.; Sachdeva, Gairik; Silver, Pamela A.


    Hydrogenases catalyze the reversible reaction 2H+ + 2e-↔H2 with an equilibrium constant that is dependent on the reducing potential of electrons carried by their redox partner. To examine the possibility of increasing the photobiological production of hydrogen within cyanobacterial cultures, we expressed the [FeFe] hydrogenase, HydA, from Clostridium acetobutylicum in the non-nitrogen-fixing cyanobacterium Synechococcus elongatus sp. 7942. We demonstrate that the heterologously expressed hydrogenase is functional in vitro and in vivo, and that the in vivo hydrogenase activity is connected to the light-dependent reactions of the electron transport chain. Under anoxic conditions, HydA activity is capable of supporting light-dependent hydrogen evolution at a rate > 500-fold greater than that supported by the endogenous [NiFe] hydrogenase. Furthermore, HydA can support limited growth solely using H2 and light as the source of reducing equivalents under conditions where Photosystem II is inactivated. Finally, we demonstrate that the addition of exogenous ferredoxins can modulate redox flux in the hydrogenase-expressing strain, allowing for greater hydrogen yields and for dark fermentation of internal energy stores into hydrogen gas. PMID:21368150

  17. Have Technology and Multitasking Rewired How Students Learn? (United States)

    Willingham, Daniel T.


    Cognitive science is an interdisciplinary field of researchers from psychology, neuroscience, linguistics, philosophy, computer science, and anthropology who seek to understand the mind. In this article, the author considers findings from this field that are strong and clear enough to merit classroom application. He examines how technology has…

  18. Neuropsychological Definition of Learning: Strategies for Rewiring Neural Networks (United States)

    Barwegen, Laura


    For many years, most scientists believed that the physical structure of our brains, and by definition the people we had become, was set after the initial developmental period of early childhood and adolescence. New research in the area of neurology and neuropsychology is revealing that our brain is a much more open system than ever thought…

  19. A model for routing problem in quay management problem (United States)

    Zirour, Mourad; Oughalime, Ahmed; Liong, Choong-Yeun; Ismail, Wan Rosmanira; Omar, Khairuddin


    Quadratic Assignment Problem (QAP), like Vehicle Routing Problem, is one of those optimization problems that interests many researchers in the last decades. The Quay Management Problem is a specific problem which could be presented as a QAP which involves a double assignment of customers and products toward loading positions using lifting trucks. This study focuses on the routing problem while delivering the customers' demands. In this problem, lifting trucks will route around the storage sections to collect the products then deliver to the customers who are assigned to specific loading positions. The objective of minimizing the residence time for each customer is sought. This paper presents the problem and the proposed model.

  20. Eldercare at Home: Breathing Problems (United States)

    ... Join our e-newsletter! Resources Eldercare at Home: Breathing Problems Caregiving How Tos Understanding the Problem As ... However, aging sometimes brings on other more serious breathing problems including incapacitating shortness of breath, chest discomfort, ...

  1. How to solve mathematical problems

    CERN Document Server

    Wickelgren, Wayne A


    Seven problem-solving techniques include inference, classification of action sequences, subgoals, contradiction, working backward, relations between problems, and mathematical representation. Also, problems from mathematics, science, and engineering with complete solutions.

  2. Common Sleep Problems (For Teens) (United States)

    ... Safe Videos for Educators Search English Español Common Sleep Problems KidsHealth / For Teens / Common Sleep Problems What's ... have emotional problems, like depression. What Happens During Sleep? You don't notice it, of course, but ...

  3. Buffon's Coin Problem and beyond (United States)

    Schneiter, Kady


    This article describes an investigation of Buffon's coin problem and related problems with the aid of an applet. The problems are accessible at a variety of grade levels and facilitate making connections between geometry and probability.

  4. Eldercare at Home: Mobility Problems (United States)

    ... Join our e-newsletter! Resources Eldercare at Home: Mobility Problems Caregiving How Tos Understanding the Problem The ... with a person’s ability to move around, or mobility. Mobility problems may be unsteadiness while walking, difficulty ...

  5. Thermodynamic problems on HCPWR

    International Nuclear Information System (INIS)

    Akiyama, Mie


    A HCPWR design uses the high compact lattice core of 1 to 2 mm fuel rod pitch in order to decrease the water volume fraction to fuel. But such high compactness is considered to cause the decrease of coolant flow rate due to the increase of core pressure loss. And the high compactness also affects the DNB phenomena itself which is directly related to the output performance. Moreover, the coolability of the reactor core is considered to be affected at an accident. It is one of the most important problems for realizing a HCPWR plant whether or not we can design a reactor that preserves the output performance under the consideration of such thermodynamic affections. The thermodynamic affections caused by high compactness are arranged in this report, and the further research problems on HCPWR are also considered on presently available knowledge. (author)

  6. 2-Sensor Problem

    Directory of Open Access Journals (Sweden)

    Michael Segal


    Full Text Available Abstract: Ad-hoc networks of sensor nodes are in general semi-permanently deployed. However, the topology of such networks continuously changes over time, due to the power of some sensors wearing out to new sensors being inserted into the network, or even due to designers moving sensors around during a network re-design phase (for example, in response to a change in the requirements of the network. In this paper, we address the problem of covering a given path by a limited number of sensors — in our case to two, and show its relation to the well-studied matrix multiplication problem.

  7. Problems of judiciary trust

    Directory of Open Access Journals (Sweden)

    Vuković Slobodan


    Full Text Available Topic of the article is problem of trust in judiciary as a most important part of legal system. For all empirical researches so far have shown very law degree of this trust many authors were searching for the causes of this phenomenon. Among multifold causes some are special worth while to be mentioned here: historical inheritance, political pressures, delaying of judiciary decisions, respect of the laws, transferring of responsibility from political power to the judiciary, public comments of judiciary decisions, media pressures, efficiency of judiciary and police. Among inner factors author pays attention to competency of judges, modes of penal policy, modes of judges’ entitlement, problems of communication, involvement into criminal and corruptional affairs, etc.

  8. FBST for Cointegration Problems (United States)

    Diniz, M.; Pereira, C. A. B.; Stern, J. M.


    In order to estimate causal relations, the time series econometrics has to be aware of spurious correlation, a problem first mentioned by Yule [21]. To solve the problem, one can work with differenced series or use multivariate models like VAR or VEC models. In this case, the analysed series are going to present a long run relation i.e. a cointegration relation. Even though the Bayesian literature about inference on VAR/VEC models is quite advanced, Bauwens et al. [2] highlight that "the topic of selecting the cointegrating rank has not yet given very useful and convincing results." This paper presents the Full Bayesian Significance Test applied to cointegration rank selection tests in multivariate (VAR/VEC) time series models and shows how to implement it using available in the literature and simulated data sets. A standard non-informative prior is assumed.

  9. – environmental problems

    Directory of Open Access Journals (Sweden)

    Maria Łebkowska


    Full Text Available Adhesives are substances that increase the surface adhesion of bonded items. Unfortunately, they also emit volatile organic compounds (VOCs which negatively impact upon human and animal health. VOCs have carcinogenic and mutagenic properties and can cause migraines, irritation to the eyes, nasal passages, mouth, and lungs, and respiratory problems. Wastewater from adhesive production is characterized by high levels of pollutants and contains high concentrations of compounds including formaldehyde that are toxic to water biocenoses. Moreover, its purification causes many problems and requires the application of specific methods. This review presents data concerning the toxicity and ecotoxicity of selected adhesives components. VOC emission rates from adhesives and wooden construction elements with adhesives are also discussed and assessed. Current knowledge on the treatment methods for wastewater containing adhesive components is reviewed. Finally, the treatment and disposal methods for solid wooden waste containing adhesives are also analyzed and discussed.

  10. The grasshopper problem (United States)

    Goulko, Olga; Kent, Adrian


    We introduce and physically motivate the following problem in geometric combinatorics, originally inspired by analysing Bell inequalities. A grasshopper lands at a random point on a planar lawn of area 1. It then jumps once, a fixed distance d, in a random direction. What shape should the lawn be to maximize the chance that the grasshopper remains on the lawn after jumping? We show that, perhaps surprisingly, a disc-shaped lawn is not optimal for any d>0. We investigate further by introducing a spin model whose ground state corresponds to the solution of a discrete version of the grasshopper problem. Simulated annealing and parallel tempering searches are consistent with the hypothesis that, for d<π-1/2, the optimal lawn resembles a cogwheel with n cogs, where the integer n is close to π (arcsin⁡(√{π }d / 2 )) -1. We find transitions to other shapes for d ≳π-1 / 2.

  11. Problems of licensing


    Heřman, Karel


    This work concerns with possibilities of licensing. There are mentioned advantages and disadvantages of particular models. Further on, the prediction of future situation in the IT market, new techniques, trends and reasons of these changes are introduced. Work addresses to both types of software -- proprietary software and Open Source software. Next part of work deals with software piracy and problems, which are connected with it. In second part of the work are theoretical knowledge converted...

  12. Problems in quantum mechanics

    CERN Document Server

    Constantinescu, Florin; Spiers, JA


    International Series in Natural Philosophy, Volume 30: Problems in Quantum Mechanics focuses on the processes, principles, reactions, and methodologies involved in quantum mechanics. The publication first elaborates on the mathematical formalism of quantum mechanics, simple quantum systems, and mean values and uncertainty relations. Discussions focus on mean values of dynamical variables, uncertainty relations, eigenfunctions and the energy spectrum, motion in a central field, matrix representation of vectors and operators, Hubert spaces, and operators in Hilbert space. The text then takes a l

  13. Problems of Chernobyl

    International Nuclear Information System (INIS)

    Shcherbyin, V.M.


    The collection comprises the materials of working meeting 'The Development of Technologies of the 'Ukrytie' Radioactive Waste Management', held on May 20-21, 1997 in Chernobyl. The results of research work of the experts of Ukraine and other countries directed on solving problems, concerning removal of fuel containing materials and other radioactive waste from destroyed Unit 4 of Chernobyl NPP are given. The data on waste quantities, their location and classification, strategy of waste management and some technologies are described

  14. The inhomogeneous Suslov problem

    Energy Technology Data Exchange (ETDEWEB)

    García-Naranjo, Luis C., E-mail: [Departamento de Matemáticas y Mecánica, IIMAS-UNAM, Apdo Postal 20-726, Mexico City 01000 (Mexico); Maciejewski, Andrzej J., E-mail: [J. Kepler Institute of Astronomy, University of Zielona Góra, Licealna 9, 65-417 Zielona Góra (Poland); Marrero, Juan C., E-mail: [ULL-CSIC, Geometría Diferencial y Mecánica Geométrica, Departamento de Matemática Fundamental, Facultad de Matemáticas, Universidad de la Laguna, La Laguna, Tenerife, Canary Islands (Spain); Przybylska, Maria, E-mail: [Institute of Physics, University of Zielona Góra, Licealna 9, 65-417 Zielona Góra (Poland)


    We consider the Suslov problem of nonholonomic rigid body motion with inhomogeneous constraints. We show that if the direction along which the Suslov constraint is enforced is perpendicular to a principal axis of inertia of the body, then the reduced equations are integrable and, in the generic case, possess a smooth invariant measure. Interestingly, in this generic case, the first integral that permits integration is transcendental and the density of the invariant measure depends on the angular velocities. We also study the Painlevé property of the solutions. - Highlights: • We consider the Suslov problem of nonholonomic rigid body motion with inhomogeneous constraints. • We study the problem in detail for a particular choice of the parameters that has a clear physical interpretation. • We show that the equations of motion possess an invariant measure whose density depends on the velocity variables. • We show that the reduced system is integrable due to the existence of a transcendental first integral. • We study the Painlevé property of the solutions.

  15. Problems in particle theory (United States)

    Adler, Stephen L.; Wilczek, Frank


    This report is a progress report on the work of two principal investigators in the broad area of particle physics theory, covering their personal work, that of their coworkers, and their proposed work for the future. One author has worked in the past on various topics in field theory and particle physics, among them current algebras, the physics of neutrino induced reactions, quantum electrodynamics (including strong magnetic field processes), the theory of the axial-vector current anomaly, topics in quantum gravity, and nonlinear models for quark confinement. While much of his work has been analytical, all of the projects listed above (except for the work on gravity) had phases which required considerable computer work as well. Over the next several years, he proposes to continue or initiate research on the following problems: (1) acceleration algorithms for the Monte Carlo analysis of lattice field and gauge theories, and more generally, new research in computational neuroscience and pattern recognition; (2) construction of quaternionic generalizations of complex quantum mechanics and field theory, and their application to composite models of quarks and leptons, and to the problem of unifying quantum theories of matter with general relativity. One author has worked on problems in exotic quantum statistics and its applications to condensed matter systems. His work has also continued on the quantum theory of black holes. This has evolved toward understanding properties of quantum field theory and string theory in incomplete regions of flat space.

  16. Ear Problems in Swimmers

    Directory of Open Access Journals (Sweden)

    Mao-Che Wang


    Full Text Available Acute diffuse otitis externa (swimmer's ear, otomycosis, exostoses, traumatic eardrum perforation, middle ear infection, and barotraumas of the inner ear are common problems in swimmers and people engaged in aqua activities. The most common ear problem in swimmers is acute diffuse otitis externa, with Pseudomonas aeruginosa being the most common pathogen. The symptoms are itching, otalgia, otorrhea, and conductive hearing loss. The treatment includes frequent cleansing of the ear canal, pain control, oral or topical medications, acidification of the ear canal, and control of predisposing factors. Swimming in polluted waters and ear-canal cleaning with cotton-tip applicators should be avoided. Exostoses are usually seen in people who swim in cold water and present with symptoms of accumulated debris, otorrhea and conductive hearing loss. The treatment for exostoses is transmeatal surgical removal of the tumors. Traumatic eardrum perforations may occur during water skiing or scuba diving and present with symptoms of hearing loss, otalgia, otorrhea, tinnitus and vertigo. Tympanoplasty might be needed if the perforations do not heal spontaneously. Patients with chronic otitis media with active drainage should avoid swimming, while patients who have undergone mastoidectomy and who have no cavity problems may swim. For children with ventilation tubes, surface swimming is safe in a clean, chlorinated swimming pool. Sudden sensorineural hearing loss and some degree of vertigo may occur after diving because of rupture of the round or oval window membrane.

  17. A further problem of the hard problem of consciousness | Gbenga ...

    African Journals Online (AJOL)

    Justifying this assertion is identified as the further problem of the hard problem of consciousness. This shows that assertions about phenomenal properties of mental experiences are wholly epistemological. Hence, the problem of explaining phenomenal properties of a mental state is not a metaphysical problem, and what is ...

  18. Characteristics of Problems in Problem-based Learning

    NARCIS (Netherlands)

    N. Sockalingam (Nachamma)


    textabstractThis thesis focuses on characteristics of problems in Problem-based Learning (PBL). Problems initiate the students’ learning process in PBL. Several studies have shown that the quality of problems has a positive influence on students’ academic achievement and interest. In addition, the

  19. Thinking Process of Naive Problem Solvers to Solve Mathematical Problems (United States)

    Mairing, Jackson Pasini


    Solving problems is not only a goal of mathematical learning. Students acquire ways of thinking, habits of persistence and curiosity, and confidence in unfamiliar situations by learning to solve problems. In fact, there were students who had difficulty in solving problems. The students were naive problem solvers. This research aimed to describe…

  20. Hodge decomposition of information flow on small-world networks

    Directory of Open Access Journals (Sweden)

    Taichi Haruna


    Full Text Available We investigate the influence of the small-world topology on the composition of information flow on networks. By appealing to the combinatorial Hodge theory, we decompose information flow generated by random threshold networks on the Watts-Strogatz model into three components: gradient, harmonic and curl flows. The harmonic and curl flows represent globally circular and locally circular components, respectively. The Watts-Strogatz model bridges the two extreme network topologies, a lattice network and a random network, by a single parameter that is the probability of random rewiring. The small-world topology is realized within a certain range between them. By numerical simulation we found that as networks become more random the ratio of harmonic flow to the total magnitude of information flow increases whereas the ratio of curl flow decreases. Furthermore, both quantities are significantly enhanced from the level when only network structure is considered for the network close to a random network and a lattice network, respectively. Finally, the sum of these two ratios takes its maximum value within the small-world region. These findings suggest that the dynamical information counterpart of global integration and that of local segregation are the harmonic flow and the curl flow, respectively, and that a part of the small-world region is dominated by internal circulation of information flow.

  1. Obstacle problems in mathematical physics

    CERN Document Server

    Rodrigues, J-F


    The aim of this research monograph is to present a general account of the applicability of elliptic variational inequalities to the important class of free boundary problems of obstacle type from a unifying point of view of classical Mathematical Physics.The first part of the volume introduces some obstacle type problems which can be reduced to variational inequalities. Part II presents some of the main aspects of the theory of elliptic variational inequalities, from the abstract hilbertian framework to the smoothness of the variational solution, discussing in general the properties of the free boundary and including some results on the obstacle Plateau problem. The last part examines the application to free boundary problems, namely the lubrication-cavitation problem, the elastoplastic problem, the Signorini (or the boundary obstacle) problem, the dam problem, the continuous casting problem, the electrochemical machining problem and the problem of the flow with wake in a channel past a profile.

  2. Space Power Engineering Problems (United States)

    Senkevich, V. P.


    Development of space power engineering in the first half of XXI century shall be aimed at preventing the forthcoming energy crisis and ecological catastrophes. The problem can be solved through using solar energy being perpetual, endless, and ecologically safe. As of now, issues on the development and employment of solar power stations and its beaming to the ground stations in the SHF band are put on the agenda. The most pressing problem is to develop orbital solar reflectors to illuminate towns in the polar regions, agricultural regions, and areas of processing sea products. Space-based technologies can be used to deal with typhoons, green house effects, and "ozone holes". Recently, large, frameless film structures formed by centrifugal forces offer the promise of structures for orbital power plants, reflectors, and solar sails. A big success is achieved in the development of power generating solar array elements of amorphous silicon. These innovations would make the development of orbital solar power plants dozens of times cheaper. Such solar arrays shall be used in the nearest future on heavy communication satellites and the Earth remote sensing platforms for generation of 140-160 kW at a specific power beyond 300 W/kg. The cargo traffic needed to develop and maintain the orbital power plants and reflector systems could be equipped with solar sails as the future low thrust propulsion. In 2000, the mankind witnessed an unexpected beginning of energy crisis along with strong hydro- meteorological events (typhoons, floods) that shocked the USA, the Western Europe, England, Japan, and other countries. The total damage is estimated as 90 billions of dollars. The mankind is approaching a boundary beyond which its further existence would depend on how people would learn to control weather and use ecologically safe power sources. Space technology base on the research potential accumulated in the previous century could serve for the solution of this problem.

  3. The world food problem

    International Nuclear Information System (INIS)

    Olson, R.A.


    Argument continues in the world press as to the urgency of the food problem. Some economists in equating world food production statistics with population figures have convinced themselves there is more than enough food per capita and, accordingly, no problem. Looking in greater depth than these gross averages, however, we find that there is indeed a prospective problem, and of such a nature and magnitude as to tax all of mankind's talents and resources in its resolution. It is true that certain of the developed countries of the world in the last generation acquired agricultural production capabilities that notably exceeded the resident population's capacity to consume. 'Surplus' in these areas became an ugly word during this period of a generally favorable weather cycle, and restrictions on the amount of and that could be devoted to graincrops were imposed to curb this tremendous capacity. A fickle Mother Nature, however, has turned things around during the early 1970's by one or another of her many vacillations in the form of local drought, excess moisture, shortened growing season, or other means, in some of the major producing areas. Inconsequence, the food grain surpluses are now gone and the world is looking at a three to four week reserve at any given moment. The cost of food products available from exporting countries has doubled and trebled in price during the past two years. The potential for famine exceeds in magnitude anything the world has ever known. It is against this background that the World Food Conference will be held in Rome during November of this year. (author)

  4. Problems of political corruption

    Directory of Open Access Journals (Sweden)

    Ćirić Jovan


    Full Text Available The author in this work speaks about general problems of political corruption in the world and in Serbia. The author tries to define the phenomenon of political corruption and pays special attention to financing political parties. Ćirić gives the overview of international documents about financing political parties and gives us the overview of MP's salaries in some western countries. At the end it is analyzed the question of trading MP's mandate, as a matter of fact who is the owner of the mandate of one representative - that representative, or his/her political party. That also could be the origin of different manipulations and corruption.

  5. The nanostructure problem

    International Nuclear Information System (INIS)

    Billinge, S.


    Diffraction techniques are making progress in tackling the difficult problem of solving the structures of nanoparticles and nanoscale materials. The great gift of x-ray crystallography has made us almost complacent in our ability to locate the three-dimensional coordinates of atoms in a crystal with a precision of around 10 -4 nm. However, the powerful methods of crystallography break down for structures in which order only extends over a few nanometers. In fact, as we near the one hundred year mark since the birth of crystallography, we face a resilient frontier in condensed matter physics: our inability to routinely and robustly determine the structure of complex nanostructured and amorphous materials. Knowing the structure and arrangement of atoms in a solid is so fundamental to understanding its properties that the topic routinely occupies the early chapters of every solid-state physics textbook. Yet what has become clear with the emergence of nanotechnology is that diffraction data alone may not be enough to uniquely solve the structure of nanomaterials. As part of a growing effort to incorporate the results of other techniques to constrain x-ray refinements - a method called 'complex modeling' which is a simple but elegant approach for combining information from spectroscopy with diffraction data to solve the structure of several amorphous and nanostructured materials. Crystallography just works, so we rarely question how and why this is so, yet understanding the physics of diffraction can be very helpful as we consider the nanostructure problem. The relationship between the electron density distribution in three dimensions (i.e., the crystal structure) and an x-ray diffraction pattern is well established: the measured intensity distribution in reciprocal space is the square of the Fourier transform of the autocorrelation function of the electron density distribution ρ(r). The fact that we get the autocorrelation function (rather than just the density

  6. Radiological waste problems

    International Nuclear Information System (INIS)

    Milanov, M.


    The chapter offers a description of the system of radioactive waste treatment as presented in the Belene NPP technical project and goes beyond the scope of the project evaluation in the account of the radioactive waste treatment, storage and disposal of other sources including the industry, science and the medicine of Bulgaria. The necessity for a developed legislative basis and an accepted policy regarding the radioactive waste management in the country is stressed upon. There is an elaboration on the problem of the construction of a new radioactive waste depository, the capacities of the existing disposal site being used up. 17 refs., 7 tabs. (R.Ts.)

  7. Elementary topology problem textbook

    CERN Document Server

    Viro, O Ya; Netsvetaev, N Yu; Kharlamov, V M


    This textbook on elementary topology contains a detailed introduction to general topology and an introduction to algebraic topology via its most classical and elementary segment centered at the notions of fundamental group and covering space. The book is tailored for the reader who is determined to work actively. The proofs of theorems are separated from their formulations and are gathered at the end of each chapter. This makes the book look like a pure problem book and encourages the reader to think through each formulation. A reader who prefers a more traditional style can either find the pr

  8. Pizza Race Problem


    Gao, Keyue


    This paper deals with a problem in which two players share a previously sliced pizza and try to eat as much amount of pizza as they can. It takes time to eat each piece of pizza and both players eat pizza at the same rate. One is allowed to take a next piece only after the person has finished eating the piece on hand. Also, after the first piece is taken, one can only take a piece which is adjacent to already-taken piece. This paper shows that, in this real time setting, the starting player c...

  9. The confinement problem

    International Nuclear Information System (INIS)

    Seiler, E.


    Confinement of quarks is sometimes taken as some kind of dogma in the contemporary theory of strong interactions - quantum chromo-dynamics (QCD). Scientists should not be content with that. What is meant by ''permanent confinement'' should be formulated more precisely to see whether the theory has this property or not. The author looks at some possible interpretations of ''confinement'' and their shortcomings and then turns to the most widely used rather pragmatic definition based on the somewhat unphysical notion of infinitely heavy external sources. He describes what is known about the problem and tries to bring into focus some aspects that are insufficiently understood in his opinion

  10. The Container Stowage Problem

    DEFF Research Database (Denmark)

    Janstrup, Kira; Rose, Trine Høyer; Andersen, Kent Høj

    The main purpose of this project is to use integer programming to create a model that minimizes the costs for container transportation by ship. To make the model as realistic as possible it will be based on information from a large shipping company about the vessel layout and container types....... In addition to our project two other projects are made where an optimal solution to the container stowage problem also is tried to be found, but by using constraint programming and local search instead respectively. We will therefore in the end compare these three methods and the achieved results on fastness...

  11. The Container Stowage Problem

    DEFF Research Database (Denmark)

    Janstrup, Kira


    The main purpose of this project is to use integer programming to create a model that minimizes the costs for container transportation by ship. To make the model as realistic as possible it will be based on information from a large shipping company about the vessel layout and container types....... In addition to our project two other projects are made where an optimal solution to the container stowage problem also is tried to be found, but by using constraint programming and local search instead respectively. We will therefore in the end compare these three methods and the achieved results on fastness...

  12. Problems in Cybersemiotic Modelling

    DEFF Research Database (Denmark)

    Brier, Søren


    on the basis of the evolutionary semiotics paradigm of C.S. Peirce . Semiotics underlines realism more, but is also relational in its whole project. In Cybersemiotics the autopoietic model in integrated in the Peircean framework which is of a far greater scope than autopoiesis. Thus in Cybersemiotic we have...... Uexküll’s cybernetic-behavioral model, which has the problem of being placed in a Platonic, static worldview. The Umwelt of an animal is a construction limited of its functional realism of survival. It is connected to the species. 2. Ture von Uexküll and Søren Brier both realized that Maturana and Varela...

  13. Problem Based Learning Online

    DEFF Research Database (Denmark)

    Kolbæk, Ditte


    “How do two online learning designs affect student engagement in the PBL online modules?” The empirical data were collected and analyzed using a netnographic approach. The study finds that concepts such as self-directed learning and active involvement may be perceived very differently from the students......Problem- and project- based learning (PBL) was originally developed for collaboration between physically present students and teachers, but political decisions at many universities also require that collaboration, dialogues, and other PBL activities take place online. Teachers design learning...

  14. The Birthday-Lunch Problem. (United States)

    Mathematics Teaching in the Middle School, 1996


    Three responses from teachers to a problem originally presented in the January-February 1996 issue are shared. The problem concerns sharing a fraction of a meal's price between six diners. Each response reflects a different approach to the problem and to using the problem with a class of students. (AIM)

  15. Problem Solving in the Professions. (United States)

    Jackling, Noel; And Others


    It is proposed that algorithms and heuristics are useful in improving professional problem-solving abilities when contextualized within the academic discipline. A basic algorithm applied to problem solving in undergraduate engineering education and a similar algorithm applicable to legal problems are used as examples. Problem complexity and…

  16. Dimensions of problem based learning

    DEFF Research Database (Denmark)

    Nielsen, Jørgen Lerche; Andreasen, Lars Birch


    The article contributes to the literature on problem based learning and problem-oriented project work, building on and reflecting the experiences of the authors through decades of work with problem-oriented project pedagogy. The article explores different dimensions of problem based learning such...

  17. Design Problems for Secondary Students (United States)

    Jonassen, David H.


    Are there different kinds of design problems? Jonassen (2011) argued that problems vary in terms of structuredness, complexity, and context. On the structuredness and complexity continua, design problems tend to be the most ill-structured and complex. Brown and Chandrasekaran suggest that design problems may vary along a continuum from…

  18. Problem situations in management activity




    This article reviews contemporary methodological and theoretical approaches to the problem situations in management activity. Revealed and analyzed the types of problem situations managers dealing with in their activity. Rank correlation of problem situations shows distinctions depending on management work experience. Revealed gender distinctions in the managers' ideas of management problems.

  19. Sedimentation problems and solutions

    International Nuclear Information System (INIS)

    Williams, D.T.


    Roseires Dam and reservoir are located in Sudan, Africa on the Blue Nile River. The hydropower from the reservoir provides approximately 80% of the power used in Sudan, thus having a tremendous economic impact on the country. The reservoir was first impounded in 1966 and has been filled annually since then. The Blue Nile has historically been known to carry heavy sediment loads which is associated with erosion from overgrazing in Ethiopia, the Blue Nile's headwaters. During the flood season, the dam's turbine intakes become blocked with debris and sediment. After a severe blockage in 1981, which prevented hydropower generation for several days, consultants from USAID were asked to make recommendations on reducing the sediment and debris impacts on reservoir operations. This led to debris clearing and dredging equipment acquisitions in 1982. In 1988, blockage occurred again during the flood season. This writer was asked by the World Bank to travel to Sudan, investigate the sediment and debris problems, examine the USAID recommendations, comment on potential sediment and debris problems associated with a proposed plan to raise the dam, make additional recommendations, and return to Sudan several times to determine the effectiveness of there recommendations. This paper discussed the results of the aforementioned activities and describes the new recommendations made by this writer

  20. Urban Environmental Problems

    International Nuclear Information System (INIS)

    Situma, F.D.P.


    The rapid urbanization and resultant heavy concentration of population in urban centres have led to many urban areas failing to provide the necessary infrastructure and amenities as the demands placed on them have overwhelmed their financial and institutional capacities. In many urban areas, the capacity for resource mobilization and delivery of social services has either broken down completely or tethers on breaking point. Although in 1986 the GoK launched a new strategy for the balanced development of rural and urban areas aimed at avoiding excessive concentration of population in urban areas, the fruits of this strategy are yet to be realized. As a result, developments in urban areas have been unsustainable and environmentally unsound. The general quality of the environment has deteriorated so much so that urgent policy intervention is required. Appropriate environmental management measures and practices are needed to address the current trend of spiralling environmental problems in the context of the existing legal and institutional frameworks and makes some proposals for reform to address these problems in order to make urban areas environmentally

  1. The Schroedinger problem

    International Nuclear Information System (INIS)

    Da Costa, N.C.A.; Krause, D.; French, S.


    Schroedinger introduced discussions about the inconsistency between the classical conception of particles as individual entities and the way in which modern physics treats such particles. In particular, it is noted that quantal particles apparently appear to lack individuality, and that certain suppositions of quantum theory imply that permutations of 'identical' particles are not regarded as observable, hence implying that they must be taken as 'non-individuals' of some kind. An overview is presented in this paper of some results obtained by the authors in the field of non-reflexive logics, which have some bearings on these problems and which can perhaps provide an adequate mathematical tool for dealing with some of the fundamental features of elementary particles, such as for instance the fact that identity apparently lacks sense with respect to them, that particle permutations are not regarded as observable and that a collection of these entities cannot be considered as a set in the sense of the usual theories of sets. The main objective of the paper is to show that the nature of elementary particles can be described in terms of certain non-classical logics, despite the problems regarding their individuality. (authors). 28 refs

  2. The Password Problem

    Energy Technology Data Exchange (ETDEWEB)

    Walkup, Elizabeth [Stanford Univ., CA (United States)


    Passwords are an ubiquitous, established part of the Internet today, but they are also a huge security headache. Single sign-on, OAuth, and password managers are some of the solutions to this problem. OAuth is a new, popular method that allows people to use large, common authentication providers for many web applications. However, it comes at the expense of some privacy: OAuth makes users easy to track across websites, applications, and devices. Password managers put the power in the hands of the users, but this vulnerability survey reveals that you have to be extremely careful which program you choose. All in all, password managers are the solution of choice for home users and small organizations, but large companies will probably want to invest in their own SSO solutions.

  3. Environmental mercury problem

    Energy Technology Data Exchange (ETDEWEB)

    D' Itri, F.M.


    The urgent need to eliminate or greatly reduce the discharge of mercury into the environment is paramount to the health and well being of man. That all forms of mercury are hazardous is widely recognized, but what is more devastating to our society is that all forms of mercury appear to have the potential to be converted in to highly toxic monomethylmercury, or dimethylmercury. This paper examined the historical uses of mercury, the background concentrations of mercury, the analytical methods for the determination of mercury, the contamination of the food chain by mercury, the biological methylation of mercury, the decontamination and restoration of mercury polluted areas, the epidemiology and toxicology of mercury, and the chronology of the world's mercury poisoning problem.

  4. Problems in particle theory

    International Nuclear Information System (INIS)

    Adler, S.L.; Wilczek, F.


    Members of the Institute have worked on a number of problems including the following: acceleration algorithms for the Monte Carlo analysis of lattice field, and gauge and spin theories, based on changes of variables specific to lattices of dimension 2 ell ; construction of quaternionic generalizations of complex quantum mechanics and field theory; wave functions for paired Hall states; black hole quantum mechanics; generalized target-space duality in curved string backgrounds; gauge symnmetry algebra of the N = 2 string; two-dimensional quantum gravity and associated string theories; organizing principles from which the signal processing of neural networks in the retina and cortex can be deduced; integrable systems of KdV type; and a theory for Kondo insulators

  5. The global warming problem

    International Nuclear Information System (INIS)



    In this chapter, a discussion is presented of the global warming problem and activities contributing to the formation of acid rain, urban smog and to the depletion of the ozone layer. Globally, about two-thirds of anthropogenic carbon dioxide emissions arise from fossil-fuel burning; the rest arise primarily from deforestation. Chlorofluorocarbons are the second largest contributor to global warming, accounting for about 20% of the total. The third largest contributor is methane, followed by ozone and nitrous oxide. A study of current activities in the US that contribute to global warming shows the following: electric power plants account for about 33% of carbon dioxide emissions; motor vehicles, planes and ships (31%); industrial plants (24%); commercial and residential buildings (11%)

  6. Problems in Protein Biosynthesis (United States)

    Lengyel, Peter


    Outline of the steps in protein synthesis. Nature of the genetic code. The use of synthetic oligo- and polynucleotides in deciphering the code. Structure of the code: relatedness of synonym codons. The wobble hypothesis. Chain initiation and N-formyl-methionine. Chain termination and nonsense codons. Mistakes in translation: ambiguity in vitro. Suppressor mutations resulting in ambiguity. Limitations in the universality of the code. Attempts to determine the particular codons used by a species. Mechanisms of suppression, caused by (a) abnormal aminoacyl-tRNA, (b) ribosomal malfunction. Effect of streptomycin. The problem of "reading" a nucleic acid template. Different ribosomal mutants and DNA polymerase mutants might cause different mistakes. The possibility of involvement of allosteric proteins in template reading. PMID:5338560


    Directory of Open Access Journals (Sweden)

    David Esema


    Full Text Available Problem-Based Learning (PBL, adalah model pembelajaran yang awalnya dikembangkan di dunia pendidikan medis, namun kini telah digunakan secara luas di berbagai jenjang dan bidang pendidikan. Basis teortits dari PBL adalah kolaborativisme dan konstruktivisme. Kemitraan, keterbukaan dan kejujuran, rasa hormat, dan kepercayaan menjadi nilai-nilai yang mendasari dan sekaligus menjadi prasyarat bagi keberhasilan PBL Sintaks PBL meliputi: pengenalan dan pemahaman konsep dasar, eksplorasi fakta dan informasi relevan secara mandiri, bertukar pemahaman dalam kelompok/kelas, kesimpulan dan evaluasi. Beberapa riset mengenai PBL baik di luar maupun di dalam negeri yang dipaparkan dan dibandingkan dalam tulisan ini menunjukkan data tentang efektifitas PBL dalam kegiatan pembelajaran.

  8. The solar neutrino problem

    International Nuclear Information System (INIS)

    Zatsepin, G.


    The problem of missing solar neutrinos is reviewed and discussed. The experiments of the 70s show a solar neutrino flux to be 4 times lower than the flux predicted by the standard model of the Sun. The three possible origins of this contradiction are analysed: the cross sections of nuclear reactions going on in the internal region of the Sun must be remeasured; the unknown properties of neutrino, like neutrino oscillation or decay, must be investigated theoretically and experimentally; or the standard model of the Sun must be changed, e.g. by a periodically pulsating star model or by a model describing periodic admixtures of He-3 to the central region of the Sun. Some new models and newly proposed experiments are described. The importance of new electronic detection methods of neutrinos is underlined. (D.Gy.)

  9. Problems of Chernobyl

    International Nuclear Information System (INIS)

    Shcherbyin, V.M.


    This collection comprises the materials of the VI International Conference 'Shelter' Object', 15 years: today and future'. The topics of this issue's works cover the results of 15-year operation of the Shelter Object and investigations of conditions of its nuclear-, radiation- and general technical safety, procedures of monitoring of fuel-containing material conditions, building structures, problems of object's conversion into an ecologically safe system, preparation of technologies for radwaste (RW) management, working out of procedures using the remotely controlled facilities for diagnostics, prospecting of complicated in access Shelter Object premises, RW retrieval and management, etc. A very important role play the works aimed at the upgrade of radiation safety, protection of public and environment

  10. A stochastic control problem

    Directory of Open Access Journals (Sweden)

    William Margulies


    Full Text Available In this paper, we study a specific stochastic differential equation depending on a parameter and obtain a representation of its probability density function in terms of Jacobi Functions. The equation arose in a control problem with a quadratic performance criteria. The quadratic performance is used to eliminate the control in the standard Hamilton-Jacobi variational technique. The resulting stochastic differential equation has a noise amplitude which complicates the solution. We then solve Kolmogorov's partial differential equation for the probability density function by using Jacobi Functions. A particular value of the parameter makes the solution a Martingale and in this case we prove that the solution goes to zero almost surely as time tends to infinity.

  11. The problem of Millenarism

    Directory of Open Access Journals (Sweden)

    Erik af Edholm


    Full Text Available The myth of the recurrence of the golden age after a period of accelerating miseries ("messianic woes" in the near future is of course not peculiar to the chiliasm of the European later middle ages. On the contrary, it belongs to the basic eschatological themes of millenarism in general. These themes are found also in Hindu tradition. To determine those general characteristics of traditional Hindu society which can contribute to an explanation of the relative unimportance of peasant rebellions and the lack of chiliastic mass movements, is not a problem to be solved within the field of the history of religions. For example, the egalitarian message of the bhakti saints, disputing the hierarchy, did not preclude that the salvationist sects did adapt to the caste system. The religious movements contributed to and gave ideological form to adjustments within the existing social structure. Obviously there was little need for millenarism in this process.

  12. [Sleep problems in dementia]. (United States)

    Oka, Yasunori


    Sleep disturbance is common in patients with dementia. Circadian rhythm sleep disorders are caused by the disturbance of sleep-wake regulation in the central nervous system, disturbed input into the sensory organs, and decreased social activities. Diurnal change of serum melatonin level in Alzheimer's disease showed decreased amplitude and shifted peak secretion. Age related sleep disturbances and sleep disorders due to the neurodegeneration including REM sleep behavior disorder also increase in dementia. Identifying and treating underlying sleep disorders along with therapeutic approach to circadian mechanism is effective. Treatment of circadian abnormality in dementia require light therapy and increased daytime activity. Use of oral melatonin is also effective for the improvement of nocturnal sleep. Treatment of sleep problems in dementia also contribute to the better management of dementia.

  13. Wicked Problem Solvers. (United States)

    Edmondson, Amy C


    Companies today increasingly rely on teams that span many industries for radical innovation, especially to solve "wicked problems." So leaders have to understand how to promote collaboration when roles are uncertain, goals are shifting, expertise and organizational cultures are varied, and participants have clashing or even antagonistic perspectives. HBS professor Amy Edmondson has studied more than a dozen cross-industry innovation projects, among them the creation of a new city, a mango supply-chain transformation, and the design and construction of leading-edge buildings. She has identified the leadership practices that make successful cross-industry teams work: fostering an adaptable vision, promoting psychological safety, enabling knowledge sharing, and encouraging collaborative innovation. Though these practices are broadly familiar, their application within cross-industry teams calls for unique leadership approaches that combine flexibility, open-mindedness, humility, and fierce resolve.


    Reider, Norman


    Moral, religious and legal attitudes in attempts to control sexual behavior have interfered with a clear view of the medical and psychological aspects of homosexuality. This phenomenon is probably much less destructive of social aspects of our society and culture than is generally believed, since it is actually more widespread than is generally acknowledged. Homosexuality probably has hormonal and undoubtedly social and psychological factors, the latter of which are the only ones which can be worked with successfully in our present state of knowledge. A general practitioner's task is to aid those who wish and need help with this problem in finding psychiatric treatment in the same way that persons with any other emotional disturbance are referred. This should be carried out without bias just as with any other emotional disturbance. PMID:13426813

  15. Problem Teologis Ideologi Komunisme

    Directory of Open Access Journals (Sweden)

    Muhamad Yakub Mubaro


    Full Text Available It is known that the communism had affected the history of this world. This ideology had succeeded influencing a third of the world in less than one century after Karl Marx’s death and it had caused some revolutionary movements at some countries of the world. It is interesting to say that even what Marx had predicted about the history of human being in the future was not surely proven, but his ideas have been affecting people. But, the communism has serious problems related to the theological matter for sure. It could make people becoming atheist. Moreover, it could create the people hate their religion, but they could become religion’s antagonists. Marx’s hatred toward religions was expressed by the words: “Religion is the opium of the masses”. Then Lenin, another figure of the communism, did a discrimination to religious people, as well as, Joseph Stalin and Mao Zedong who prohibited all kinds of religious activities during their lifetime. Long time ago, thousands of Indonesian Moslems were becoming victims of a communist party in Indonesia (PKI. Nowadays, the communism doctrine begins to appear and affect some youths of Indonesia. Perhaps, it does because they have been frustrated and being disappointed by the socio-political condition which is controlled by modern capitalists. But, they have to be aware that the communism is not a solution. In fact, it is surely dangerous. It could ruin religions’ concepts. Hence, this article would try to explain some theological problems of the communism ideology.

  16. The worldwide "wildfire" problem. (United States)

    Gill, A Malcolm; Stephens, Scott L; Cary, Geoffrey J


    The worldwide "wildfire" problem is headlined by the loss of human lives and homes, but it applies generally to any adverse effects of unplanned fires, as events or regimes, on a wide range of environmental, social, and economic assets. The problem is complex and contingent, requiring continual attention to the changing circumstances of stakeholders, landscapes, and ecosystems; it occurs at a variety of temporal and spatial scales. Minimizing adverse outcomes involves controlling fires and fire regimes, increasing the resistance of assets to fires, locating or relocating assets away from the path of fires, and, as a probability of adverse impacts often remains, assisting recovery in the short-term while promoting the adaptation of societies in the long-term. There are short- and long-term aspects to each aspect of minimization. Controlling fires and fire regimes may involve fire suppression and fuel treatments such as prescribed burning or non-fire treatments but also addresses issues associated with unwanted fire starts like arson. Increasing the resistance of assets can mean addressing the design and construction materials of a house or the use of personal protective equipment. Locating or relocating assets can mean leaving an area about to be impacted by fire or choosing a suitable place to live; it can also mean the planning of land use. Assisting recovery and promoting adaptation can involve insuring assets and sharing responsibility for preparedness for an event. There is no single, simple, solution. Perverse outcomes can occur. The number of minimizing techniques used, and the breadth and depth of their application, depends on the geographic mix of asset types. Premises for policy consideration are presented.

  17. International safeguards problem

    International Nuclear Information System (INIS)

    Scheinman, L.; Curtis, H.B.


    To recognize the limitations of safeguards as a barrier to nuclear proliferation is not to deny their essential role in the effort to contain that problem. Without a safeguards system, international nuclear commerce and development would not, indeed could not, be what they are today. The problems evoked in the discussion of the spread of sensitive nuclear technology underscore the importance of ensuring that activities do not outpace our ability to control them. To sustain a global nuclear economy requires a readiness to live within the constraints that such an economy requires. Enhanced safeguards and strengthened national commitments to facilitate their application are key elements of those constraints. So also may be a prepardness by many nations to forego explicitly national control over all facets of the nuclear fuel cycle while still sharing fully and equally in the benefits of the peaceful atom. The challenge of the coming years will be to craft mechanisms and institutions enabling the continued growth of peaceful nuclear activity without further impairing international security. The constraints that such an outcome entails are not limited to nations lacking sophisticated nuclear technology; they apply to the most advanced nuclear nations as well--partly through adherence to the safeguards system that these countries call upon others to adopt, and partly through greater willingness to entertain solutions that may involve greater international involvement in, and control over, their own peaceful nuclear productive activities. With time, the relative incompatibility of nuclear energy with full national sovereignty, and the far-sighted wisdom of the Baruch Plan, are becoming increasingly clear. 1 table, 10 references

  18. Heuristics for Multidimensional Packing Problems

    DEFF Research Database (Denmark)

    Egeblad, Jens

    costs significantly. For packing problems in general are given a set of items and one of more containers. The items must be placed within the container such that some objective is optimized and the items do not overlap. Items and container may be rectangular or irregular (e.g. polygons and polyhedra...... methods. Two important problem variants are the knapsack packing problem and the strip-packing problem. In the knapsack packing problem, each item is given a profit value, and the problem asks for the subset with maximal profit that can be placed within one container. The strip-packing problem asks...... for a minimum height container required for the items. The main contributions of the thesis are three new heuristics for strip-packing and knapsack packing problems where items are both rectangular and irregular. In the two first papers we describe a heuristic for the multidimensional strip-packing problem...

  19. Computer Problem-Solving Coaches (United States)

    Hsu, Leon; Heller, Kenneth


    Computers might be able to play an important role in physics instruction by coaching students to develop good problem-solving skills. Building on previous research on student problem solving and on designing computer programs to teach cognitive skills, we are developing a prototype computer coach to provide students with guided practice in solving problems. In addition to helping students become better problem solvers, such programs can be useful in studying how students learn to solve problems and how and if problem-solving skills can be transferred from a computer to a pencil-and-paper environment.

  20. Mechanics problems in undergraduate physics

    CERN Document Server

    Strelkov, S P


    Problems in Undergraduate Physics, Volume I: Mechanics focuses on solutions to problems in physics. The book first discusses the fundamental problems in physics. Topics include laws of conservation of momentum and energy; dynamics of a point particle in circular motion; dynamics of a rotating rigid body; hydrostatics and aerostatics; and acoustics. The text also offers information on solutions to problems in physics. Answers to problems in kinematics, statics, gravity, elastic deformations, vibrations, and hydrostatics and aerostatics are discussed. Solutions to problems related to the laws of

  1. Problem Solving through an Optimization Problem in Geometry (United States)

    Poon, Kin Keung; Wong, Hang-Chi


    This article adapts the problem-solving model developed by Polya to investigate and give an innovative approach to discuss and solve an optimization problem in geometry: the Regiomontanus Problem and its application to football. Various mathematical tools, such as calculus, inequality and the properties of circles, are used to explore and reflect…

  2. Inverse feasibility problems of the inverse maximum flow problems

    Indian Academy of Sciences (India)

    A linear time method to decide if any inverse maximum flow (denoted General Inverse Maximum Flow problems (IMFG)) problem has solution is deduced. If IMFG does not have solution, methods to transform IMFG into a feasible problem are presented. The methods consist of modifying as little as possible the restrictions to ...

  3. The Magnet Fiducialization Problem

    International Nuclear Information System (INIS)

    Harvey, A.; SLAC


    Magnets in accelerator beamlines have, for the most part, been made with ferromagnetic poles and traditionally these pole surfaces have been used as the references for external alignment aids, tooling balls, CERN sockets and so on. This practice assumes that the magnetic field is well-defined by the poles (which fails in the presence of saturation). It also fails in the case of superconducting magnets, which have no tangible poles. Other difficulties are well-known to those working in the field: the poles of an iron dipole magnet are never perfectly flat, or perfectly parallel. Where, then, is the magnetic mid-plane? The corresponding problem for iron quadrupoles, sextupoles etc, is that there is no unique inscribed circle that is tangent to more than three of these poles. The magnetic axis is then difficult to define. The greater the precision that is sought in the alignment, the more apparent these problems become. The answer, I believe, is to use magnetic field measurements to establish the references. Most magnets undergo some magnetic measurement before use--they certainly should--and so the opportunity is there to combine fiducialization with magnetic field definition. A substantial part of the Final Focus Test Beam program at SLAC will address this problem. Meanwhile I would like to use the work of some other SLAC colleagues to illustrate one approach. As part of the installation of the new SLD detector at the Linear Collider, a pair of superconducting triplet quadrupoles will be added as the final focusing elements before the detector. Fiducials (tooling balls) on the outside of the cryostats are referenced to the magnetic axis of the quads in a set-up as shown in Fig. 1. The probe P is a small rotating coil in a warm-bore insert in the quadrupole. Its center of rotation, X p , Y p , can be found by a transit focused on an illuminated target attached to the coil, (see Fig. 2). Analysis of the dipole component of the coil output in a local PC gives the

  4. Fibromyalgia and sexual problems

    Directory of Open Access Journals (Sweden)

    P. Scarpellini


    Full Text Available The aim of this review was to describe the recent literature concerning sexual dysfunction in fibromyalgic patients. To this end, we used the common online databases PubMed, MEDLINE and EMBASE (up to June 2012 and searched for the key words fibromyalgia (FM and sexual dysfunction. All the studies examined underlined that FM is strictly associated with sexual dysfunction in women. The major findings observed were related to a decreased sexual desire and arousal, decreased experience of orgasm, and in some studies an increase in genital pain. The psychological aspects, together with the stress related to the constant presence of chronic widespread pain, fatigue and sleep disturbances, are certainly a major factor that adversely affects the sexuality of the patient with FM. Moreover, the drugs most commonly used in these cases may interfere negatively on the sexuality and sexual function of these patients. Therefore, the therapeutic intervention should be targeted and the side effects should be weighed up against the positive effects. It is of the utmost importance to recognise the problem of sexuality and sexual dysfunction in a more complex form of its expression and undertake a multidisciplinary therapeutic intervention to improve the quality of FM patients’ life.

  5. Problems in Cybersemiotic Modelling

    DEFF Research Database (Denmark)

    Brier, Søren


    ’s constructivist biology came closer to a modern version of Jacob von Uexküll’s. Maturana’s model is a relational model. Cognition and communication aims to conserve a viable relation between living system and environment. It is as such not an objective modeling. 3. This model is reinterpreted in biosemiotics......Going from an empirical to an informational paradigm of cognition and communication, does not really help us to analyze, how the living systems manage to make a meaningful interpretation of environment that is useful for their survival and procreation. Other models are needed. 1. There is von...... Uexküll’s cybernetic-behavioral model, which has the problem of being placed in a Platonic, static worldview. The Umwelt of an animal is a construction limited of its functional realism of survival. It is connected to the species. 2. Ture von Uexküll and Søren Brier both realized that Maturana and Varela...

  6. [Problems of contraception]. (United States)

    Rozenbaum, H


    Light bleeding is frequent in women who just started to wear an intrauterine device. If the bleeding does not disappear after a couple of months following the insertion, it may reveal several problems: the IUD may be stuck in the cervix; much more rarely, the bleeding indicates the beginning of an infection. If the bleeding persists outside the menstrual period for a few months after the insertion, this may indicate a real intolerance. If this intermenstrual bleeding appears at a certain time after the insertion of the intrauterine device, either there is a calcareous deposit, or the device has shifted, or there is an infection. In this last case, a thorough gynecological examination may reveal a light case of endometritis when the uterus is tender under pressure. The disorder should disappear after a few days of antibiotherapy. The IUD may not have to be removed, provided the physician performs an ulterior gynecological check-up. Bleeding between periods may also reveal an organic pathology such as a small fibroma, a polyp or endometriosis. Therefore, if there is no logical explanation for intermenstrual bleeding, one must perform a hysterography, which may be done without removing the intrauterine device.

  7. [Induced abortion, epidemiological problem]. (United States)

    Rasević, M


    A large number of induced abortions exist in central Serbia, in spite of the fact that modern science made new methods and devices for the birth control available, which are more acceptable both from the medical and personal point of view. This fact shows contradictory situation and opens several questions. The crucial being: why do wome rely on abortion and do not use modern contraception? In research done in 1991--it refers to Belgrade and it includes four hundred women--confirmed was the accepted hypothesis that the extension of induced abortion developed from the discordance between comprehension of the need of birth control and the way it should be accomplished. The main causes of the discordance are insufficient knowledge about modern contraception, phychological barriers, insufficient cultural level (general, health, sex) of the population and lack of institutionalized contemporary concept fof family planning. Duration of prevalence of induced abortions indicates that underlying causes of frequency are numerous and stable over time. Considering this, and the slowness of any spontaneous change, it may be expected that the problem of abortions will be present in the years to come. However, duration of abortion prevalence will depend, to a large extent, on the ability and willingness of the State to cope with this issue.

  8. Big projects, big problems. (United States)

    Zeide, B


    Our environmental concerns prompt launching large monitoring programs. Examining the history and accomplishments of similar endeavors is the best way to avoid errors. One lesson taught by the oldest and largest survey of national renewable resources in the United States, the Forest Inventory and Analysis Program, is that the program itself is not capable of learning from its errors. Among other problems that beset big programs are unrealistic promises. It is not possible to inventory "every animal and plant species in the United States and their habitats" as the newly created National Biological Survey vows to do. Even if it were possible, this would hardly help to attain the ultimate goal of the Survey, survival of all species. In his request to fund the Survey, Secretary of the Interior, Bruce Babbitt, compared the conflict between economic development and environmental integrity with train wrecks. This metaphor is as brilliant as it is deceitful. Its brilliance, attested by the success with the press and legislature, is in a vivid and blithe image suggesting that, given sufficient information, the conflict could be averted. After all, railroad accidents are rare and avoidable exceptions. This hopeful situation cannot be honestly compared with the plight of our environment. The crucial piece of information - that there is no spare track for economic development - is readily available. Our population and economic growth take place in the same space that has already been fully occupied by other species. To be trustworthy, monitoring programs should face the reality that development necessitates environmental degradation.

  9. Problems of high energy physics

    International Nuclear Information System (INIS)

    Kadyshevskij, V.G.


    Some problems of high energy physics are discussed. The main attention is paid to describibg the standard model. The model comprises quantum chromodynamics and electroweak interaction theory. The problem of CP breaking is considered as well. 8 refs.; 1 tab

  10. Analyzing and Solving Productivity Problems. (United States)

    Walsh, David S.; Johnson, Thomas J.


    The authors discuss ways to define a company's position on productivity, and explain productivity concepts. They describe a problem cause/solution set matrix with which to identify accurately the most probable cause of productivity problems. (SK)

  11. Eldercare at Home: Memory Problems (United States)

    ... Join our e-newsletter! Resources Eldercare at Home: Memory Problems Caregiving How Tos Understanding the Problem In ... do by themselves." These activities, especially those involving music, can be especially therapeutic. Encourage regular routines. Important ...

  12. Duality in constrained location problems

    DEFF Research Database (Denmark)

    Juel, Henrik; Love, Robert F.


    The dual of a facility location problem with general norms, distance constraints, and linear constraints is formulated.......The dual of a facility location problem with general norms, distance constraints, and linear constraints is formulated....

  13. Dementia - behavior and sleep problems (United States)

    ... this page: // Dementia - behavior and sleep problems To use the sharing ... on this page, please enable JavaScript. People with dementia , often have certain problems when it gets dark ...

  14. On the graph turnpike problem

    KAUST Repository

    Feder, Tomás


    Results on graph turnpike problem without distinctness, including its NP-completeness, and an O(m+n log n) algorithm, is presented. The usual turnpike problem has all pairwise distances given, but does not specify which pair of vertices w e corresponds to. There are two other problems that can be viewed as special cases of the graph turnpike problem, including the bandwidth problem and the low-distortion graph embedding problem. The aim for the turnpike problem in the NP-complete is to orient the edges with weights w i in either direction so that when the whole cycle is transversed in the real line, it returns to a chosen starting point for the cycle. An instance of the turnpike problem with or without distinctness is uniquely mappable if there exists at most one solution up to translation and choice of orientation.

  15. Hull properties in location problems

    DEFF Research Database (Denmark)

    Juel, Henrik; Love, Robert F.


    Some properties of the solution set for single and multifacility continuous location problems with lp distances are given. A set reduction algorithm is developed for problems in k-dimensional space having rectangular distances.......Some properties of the solution set for single and multifacility continuous location problems with lp distances are given. A set reduction algorithm is developed for problems in k-dimensional space having rectangular distances....

  16. Problem Solving Ability Of Students Mathematics In Problem Based Learning

    Directory of Open Access Journals (Sweden)

    Nurdiana Siregar


    Full Text Available The objective of this study were to determine the increasing of students’ problem solving ability and self confidence after the implementation of problem based learning and to see the interaction between gender and learning to increas problem solving ability and students’ self confidence. The method kuantitaif with the design of this research was quasi-experimental with factorial design is 22. There were 73 students as the sample of this study containing 36 students in grade VIII-5 and 37 students in grade VIII-6. The instruments of this students were test of problem solving and self confidence scale. The data were analyzed by applying two way analysis of variance (ANOVA. The result showed that (1 The increasing of students’ problem solving ability taught by using problem based learning was higher than that taught by using conventional learning (2 There was no interaction between gender and learning with increasing of students’ problem solving ability.

  17. Reducing the generalised Sudoku problem to the Hamiltonian cycle problem

    Directory of Open Access Journals (Sweden)

    Michael Haythorpe


    Full Text Available The generalised Sudoku problem with N symbols is known to be NP-complete, and hence is equivalent to any other NP-complete problem, even for the standard restricted version where N is a perfect square. In particular, generalised Sudoku is equivalent to the, classical, Hamiltonian cycle problem. A constructive algorithm is given that reduces generalised Sudoku to the Hamiltonian cycle problem, where the resultant instance of Hamiltonian cycle problem is sparse, and has O(N3 vertices. The Hamiltonian cycle problem instance so constructed is a directed graph, and so a (known conversion to undirected Hamiltonian cycle problem is also provided so that it can be submitted to the best heuristics. A simple algorithm for obtaining the valid Sudoku solution from the Hamiltonian cycle is provided. Techniques to reduce the size of the resultant graph are also discussed.

  18. Framework of synchromodal transportation problems

    NARCIS (Netherlands)

    Juncker, M.A.M. de; Huizing, D.; Vecchyo, M.R.O. del; Phillipson, F.; Sangers, A.


    Problem statements and solution methods in mathematical synchromodal transportation problems depend greatly on a set of model choices for which no rule of thumb exists. In this paper, a framework is introduced with which the model choices in synchromodal transportation problems can be classified,

  19. Problem gambling and social work


    Rogers, Jim


    This presentation summarises research on problem gambling and gambling related harm which is of relevance to social work practice. Issues in relation to adults with care and support needs are highlighted, methods of identifying and screening for gambling problems summarised, and information on ways of helping and signposting problem gamblers to helping agencies presented.

  20. Collaborative problem structuring using MARVEL

    NARCIS (Netherlands)

    Veldhuis, G.A.; Scheepstal, P.G.M. van; Rouwette, E.A.J.A.; Logtens, T.W.A.


    When faced with wicked and messy problems, practitioners can rely on a variety of problem structuring methods (PSMs). Although previous efforts have been made to combine such methods with simulation, currently, few exist that integrate a simulation capability within problem structuring. Our

  1. Hierarchy problem and BSM physics

    Indian Academy of Sciences (India)


    Oct 5, 2017 ... The 'hierarchy problem' plagues the Standard Model of particle physics. The source of this problem is our inability to answer the following question: Why is the Higgs mass so much below the GUT or Planck scale? A brief description about how 'supersymmetry' and 'composite Higgs' address this problem is ...

  2. Problems of group dynamics in problem based learning sessions. (United States)

    Ahmed, Zafar


    Beneficial effects of Problem Based Learning (PBL) in medical education are often emphasized. However, there is another side of the coin. This study was conducted to find out frequency of PBL group problems in our setup and the influence of these problems on students' learning. We also compared the perception of students and tutors as regard to frequency and level of hindrance caused by these problems in PBL sessions. This cross sectional study was conducted at Foundation University Medical College, Islamabad. 100 students of 3rd year MBBS of 2011 and their 17 PBL tutors were asked to fill a questionnaire. They were asked to rank the factors according to frequency (perceived frequency) and according to the level of hindrance to learning these factors are causing. All data was entered and analysed using SPSS-12. Students ranked "Dominant student" as the most important problem and. "Psychosocial factors" as the least important problem. Tutors ranked "Quiet student" as the-most important problem and "Personality clash" as the least important factor. Student's ranked "Dominant student" as the problem causes most hindrance and "Quiet student" as the problem causing least hindrance. Tutors ranked "Lack of commitment" as the problem causing most hindrance and "Personality clash" as the problem causing least hindrance. There was good agreement between the students and the tutors on all the factors regarding important problem except "Lateness, absenteeism" (p = 0.04) and "Personality clash" (p = 0.001). Similarly there was good agreement between the students and the tutors on all the factors regarding hindrance except "Lack of commitment" (p = 0.015) and "Personality clash" (p = 0.023). The present study showed that from both students' and tutors' perspectives, the ranking of most important problems that can disturb PBL session function and the level of hindrance they cause were statistically similar for majority of the problems.

  3. Medical-biological problems

    International Nuclear Information System (INIS)


    The report contains data on operational and emergency staff of the Chernobyl nuclear power plant who were exposed to radiation as a consequence of the reactor accident, the size of the doses received and consequences for health. 203 persons were found to have acute radiation sickness. Of the 22 patients suffering from an extremely severe degree of acute radiation sickness, 19 died. Of the 23 patients with severe bone marrow syndrome, 7 died. For the majority of patients, clinical recovery occurred toward the end of the second month following the accident. The main harmful factor for all victims was the relatively uniform gamma- and beta-radiation effect in a dosage exceeding 1 Gy and, in the case of 35 people exceeding 4 Gy. Radiation damage to wide areas of the skin was one of the main factors contributing to the overall severe condition of the patients, and was a determining factor in the main fatal complications. A preliminary evaluation of the use of some biochemical and immunological tests in the event of accidental exposure to radiation and the methods of treatment and preliminary assessment of their effectiveness are presented. Another part of the report contains data on the doses from radiation exposure to the population of the town of Pripyat' until the time of evacuation and to the population in the 30 km zone around Chernobyl' nuclear power plant and radiation consequences of the accident for the population of different regions in the European part of the USSR, especially the problems related to the contamination of food products. The last part of the report gives some data on the organization of medical examinations of the population from the region around the Chernobyl' plant and on the long-term programmes for the medical and biological monitoring of the population and personnel

  4. A rainbow inverse problem

    Directory of Open Access Journals (Sweden)

    Calvez V.


    Full Text Available We consider the radiative transfer equation (RTE with reflection in a three-dimensional domain, infinite in two dimensions, and prove an existence result. Then, we study the inverse problem of retrieving the optical parameters from boundary measurements, with help of existing results by Choulli and Stefanov. This theoretical analysis is the framework of an attempt to model the color of the skin. For this purpose, a code has been developed to solve the RTE and to study the sensitivity of the measurements made by biophysicists with respect to the physiological parameters responsible for the optical properties of this complex, multi-layered material. On étudie l’équation du transfert radiatif (ETR dans un domaine tridimensionnel infini dans deux directions, et on prouve un résultat d’existence. On s’intéresse ensuite à la reconstruction des paramètres optiques à partir de mesures faites au bord, en s’appuyant sur des résultats de Choulli et Stefanov. Cette analyse sert de cadre théorique à un travail de modélisation de la couleur de la peau. Dans cette perspective, un code à été développé pour résoudre l’ETR et étudier la sensibilité des mesures effectuées par les biophysiciens par rapport aux paramètres physiologiques tenus pour responsables des propriétés optiques de ce complexe matériau multicouche.

  5. Simon on Problem-Solving

    DEFF Research Database (Denmark)

    Foss, Kirsten; Foss, Nicolai Juul

    as a general approach to problem solving. We apply these Simonian ideas to organizational issues, specifically new organizational forms. Specifically, Simonian ideas allow us to develop a morphology of new organizational forms and to point to some design problems that characterize these forms.Keywords: Herbert...... Simon, problem-solving, new organizational forms. JEL Code: D23, D83......Two of Herbert Simon's best-known papers are "The Architecture of Complexity" and "The Structure of Ill-Structured Problems." We discuss the neglected links between these two papers, highlighting the role of decomposition in the context of problems on which constraints have been imposed...

  6. Problem Prioritization in Usability Evaluation:

    DEFF Research Database (Denmark)

    Hertzum, Morten


    problems, emphasizing that to be effective severity assessments must be reliable, valid, and sufficiently persuasive to justify the cost of fixing problems. For the usability inspections, evaluators' ratings of problem impact and persistence were weakly correlated with the number of evaluators reporting...... a problem, indicating that different evaluators represent different subgroups of users or alternatively that evaluator-made severity assessments are of questionable reliability. To call designers' attention to the severe problems, the halving of the severity sum is proposed as a means of visualizing...

  7. About an Optimal Visiting Problem

    Energy Technology Data Exchange (ETDEWEB)

    Bagagiolo, Fabio, E-mail:; Benetton, Michela [Unversita di Trento, Dipartimento di Matematica (Italy)


    In this paper we are concerned with the optimal control problem consisting in minimizing the time for reaching (visiting) a fixed number of target sets, in particular more than one target. Such a problem is of course reminiscent of the famous 'Traveling Salesman Problem' and brings all its computational difficulties. Our aim is to apply the dynamic programming technique in order to characterize the value function of the problem as the unique viscosity solution of a suitable Hamilton-Jacobi equation. We introduce some 'external' variables, one per target, which keep in memory whether the corresponding target is already visited or not, and we transform the visiting problem in a suitable Mayer problem. This fact allows us to overcome the lacking of the Dynamic Programming Principle for the originary problem. The external variables evolve with a hysteresis law and the Hamilton-Jacobi equation turns out to be discontinuous.

  8. KM: Problems and Opportunities

    International Nuclear Information System (INIS)

    Gulliford, J.


    : 1) providing the unique and exciting opportunity to work as part of a large, multinational, multidisciplinary effort; 2) assuring that research is practical and targeted to solve real-world problems will to help enable emerging scientists and engineers capture state-of-the-art know how; 3) providing diversity of experiences that can be tailored to the personal trajectory of individuals; 4) creating a network of future technical leaders which will be an asset for the international community. (author).

  9. Problem Reporting System (United States)

    Potter, Don; Serian, Charles; Sweet, Robert; Sapir, Babak; Gamez, Enrique; Mays, David


    The Problem Reporting System (PRS) is a Web application, running on two Web servers (load-balanced) and two database servers (RAID-5), which establishes a system for submission, editing, and sharing of reports to manage risk assessment of anomalies identified in NASA's flight projects. PRS consolidates diverse anomaly-reporting systems, maintains a rich database set, and incorporates a robust engine, which allows tracking of any hardware, software, or paper process by configuring an appropriate life cycle. Global and specific project administration and setup tools allow lifecycle tailoring, along with customizable controls for user, e-mail, notifications, and more. PRS is accessible via the World Wide Web for authorized user at most any location. Upon successful log-in, the user receives a customizable window, which displays time-critical 'To Do' items (anomalies requiring the user s input before the system moves the anomaly to the next phase of the lifecycle), anomalies originated by the user, anomalies the user has addressed, and custom queries that can be saved for future use. Access controls exist depending on a user's role as system administrator, project administrator, user, or developer, and then, further by association with user, project, subsystem, company, or item with provisions for business-to-business exclusions, limitations on access according to the covert or overt nature of a given project, all with multiple layers of filtration, as needed. Reporting of metrics is built in. There is a provision for proxy access (in which the user may choose to grant one or more other users to view screens and perform actions as though they were the user, during any part of a tracking life cycle - especially useful during tight build schedules and vacations to keep things moving). The system also provides users the ability to have an anomaly link to or notify other systems, including QA Inspection Reports, Safety, GIDEP (Government-Industry Data Exchange Program

  10. The Association between Attention Problems and Internalizing and Externalizing Problems: The Mediating Role of Peer Problems (United States)

    Yip, Vania T.; Ang, Rebecca P.; Ooi, Yoon Phaik; Fung, Daniel S. S.; Mehrotra, Kala; Sung, Min; Lim, Choon Guan


    Background: The high prevalence of attention problems in children warrants concern, as it is a risk factor for internalizing and externalizing problems. There lies a need to understand possible factors that may mediate this link so that interventions may be targeted to alleviate these mediators and interrupt the link between attention problems and…

  11. What is a problem?: On problem-oriented interdisciplinarity. (United States)

    Schmidt, Jan C


    Among others, the term "problem" plays a major role in the various attempts to characterize interdisciplinarity or transdisciplinarity, as used synonymously in this paper. Interdisciplinarity (ID) is regarded as "problem solving among science, technology and society" and as "problem orientation beyond disciplinary constraints" (cf. Frodeman et al.: The Oxford Handbook of Interdisciplinarity. Oxford University Press, Oxford, 2010). The point of departure of this paper is that the discourse and practice of ID have problems with the "problem". The objective here is to shed some light on the vague notion of "problem" in order to advocate a specific type of interdisciplinarity: problem-oriented interdisciplinarity. The outline is as follows: Taking an ex negativo approach, I will show what problem-oriented ID does not mean. Using references to well-established distinctions in philosophy of science, I will show three other types of ID that should not be placed under the umbrella term "problem-oriented ID": object-oriented ID ("ontology"), theory-oriented ID (epistemology), and method-oriented ID (methodology). Different philosophical thought traditions can be related to these distinguishable meanings. I will then clarify the notion of "problem" by looking at three systematic elements: an undesired (initial) state, a desired (goal) state, and the barriers in getting from the one to the other. These three elements include three related kinds of knowledge: systems, target, and transformation knowledge. This paper elaborates further methodological and epistemological elements of problem-oriented ID. It concludes by stressing that problem-oriented ID is the most needed as well as the most challenging type of ID.

  12. Problems of Small Debris

    Directory of Open Access Journals (Sweden)

    V. V. Zelentsov


    shell case design SC is very high. But if the particle can penetrate the shell, then the opposite side is possible breakaway material of construction and the resulting fragments can cause serious damage to equipment and communications satellites.Height SD placed unevenly. The maximum amount of it is concentrated in the most exploited heights: geostationary orbits, sun-synchronous orbit and low orbit. Fragments of SD "live" in OKP different times. At low altitudes (200 ... 400 km - from a few weeks to a year, on the sun-synchronous orbit for decades and geostationary hundreds of years.At present, the space-facing two problems: first how to protect spacecraft from damage to the small debris and clean as the second TFC from the existing SD there and take measures to eliminate clogging OKP new launches of spacecraft.

  13. Bayesian Approach to Inverse Problems

    CERN Document Server


    Many scientific, medical or engineering problems raise the issue of recovering some physical quantities from indirect measurements; for instance, detecting or quantifying flaws or cracks within a material from acoustic or electromagnetic measurements at its surface is an essential problem of non-destructive evaluation. The concept of inverse problems precisely originates from the idea of inverting the laws of physics to recover a quantity of interest from measurable data.Unfortunately, most inverse problems are ill-posed, which means that precise and stable solutions are not easy to devise. Regularization is the key concept to solve inverse problems.The goal of this book is to deal with inverse problems and regularized solutions using the Bayesian statistical tools, with a particular view to signal and image estimation

  14. Abstract Cauchy problems three approaches

    CERN Document Server

    Melnikova, Irina V


    Although the theory of well-posed Cauchy problems is reasonably understood, ill-posed problems-involved in a numerous mathematical models in physics, engineering, and finance- can be approached in a variety of ways. Historically, there have been three major strategies for dealing with such problems: semigroup, abstract distribution, and regularization methods. Semigroup and distribution methods restore well-posedness, in a modern weak sense. Regularization methods provide approximate solutions to ill-posed problems. Although these approaches were extensively developed over the last decades by many researchers, nowhere could one find a comprehensive treatment of all three approaches.Abstract Cauchy Problems: Three Approaches provides an innovative, self-contained account of these methods and, furthermore, demonstrates and studies some of the profound connections between them. The authors discuss the application of different methods not only to the Cauchy problem that is not well-posed in the classical sense, b...

  15. About an Optimal Visiting Problem

    International Nuclear Information System (INIS)

    Bagagiolo, Fabio; Benetton, Michela


    In this paper we are concerned with the optimal control problem consisting in minimizing the time for reaching (visiting) a fixed number of target sets, in particular more than one target. Such a problem is of course reminiscent of the famous “Traveling Salesman Problem” and brings all its computational difficulties. Our aim is to apply the dynamic programming technique in order to characterize the value function of the problem as the unique viscosity solution of a suitable Hamilton–Jacobi equation. We introduce some “external” variables, one per target, which keep in memory whether the corresponding target is already visited or not, and we transform the visiting problem in a suitable Mayer problem. This fact allows us to overcome the lacking of the Dynamic Programming Principle for the originary problem. The external variables evolve with a hysteresis law and the Hamilton–Jacobi equation turns out to be discontinuous

  16. Diabetes and Sexual and Urologic Problems (United States)

    ... Disease, & Other Dental Problems Diabetes & Sexual & Urologic Problems Diabetes & Sexual & Urologic Problems Troublesome bladder symptoms and changes ... early onset of these sexual and urologic problems. Diabetes and Sexual Problems Both men and women with ...

  17. Elimination Problems in Infants and Children (United States)

    ... Infants and Children Chest Pain, Acute Chest Pain, Chronic Cold and Flu Cough Diarrhea Ear Problems Elimination Problems Elimination Problems in Infants and Children Eye Problems Facial Swelling Feeding Problems in Infants ...

  18. Inverse problem in hydrogeology (United States)

    Carrera, Jesús; Alcolea, Andrés; Medina, Agustín; Hidalgo, Juan; Slooten, Luit J.


    The state of the groundwater inverse problem is synthesized. Emphasis is placed on aquifer characterization, where modelers have to deal with conceptual model uncertainty (notably spatial and temporal variability), scale dependence, many types of unknown parameters (transmissivity, recharge, boundary conditions, etc.), nonlinearity, and often low sensitivity of state variables (typically heads and concentrations) to aquifer properties. Because of these difficulties, calibration cannot be separated from the modeling process, as it is sometimes done in other fields. Instead, it should be viewed as one step in the process of understanding aquifer behavior. In fact, it is shown that actual parameter estimation methods do not differ from each other in the essence, though they may differ in the computational details. It is argued that there is ample room for improvement in groundwater inversion: development of user-friendly codes, accommodation of variability through geostatistics, incorporation of geological information and different types of data (temperature, occurrence and concentration of isotopes, age, etc.), proper accounting of uncertainty, etc. Despite this, even with existing codes, automatic calibration facilitates enormously the task of modeling. Therefore, it is contended that its use should become standard practice. L'état du problème inverse des eaux souterraines est synthétisé. L'accent est placé sur la caractérisation de l'aquifère, où les modélisateurs doivent jouer avec l'incertitude des modèles conceptuels (notamment la variabilité spatiale et temporelle), les facteurs d'échelle, plusieurs inconnues sur différents paramètres (transmissivité, recharge, conditions aux limites, etc.), la non linéarité, et souvent la sensibilité de plusieurs variables d'état (charges hydrauliques, concentrations) des propriétés de l'aquifère. A cause de ces difficultés, le calibrage ne peut êtreséparé du processus de modélisation, comme c'est le

  19. Modelling of a collage problem

    Directory of Open Access Journals (Sweden)

    Abdelaziz Ait Moussa


    Full Text Available In this paper we study the behavior of elastic adherents connected with an adhesive. We use the $Gamma$-convergence method to approximate the problem modelling the assemblage with density energies assumed to be quasiconvex. In particular for the adhesive problem, we assume periodic density energy and some growth conditions with respect to the spherical and deviational components of the gradient. We obtain a problem depending on small parameters linked to the thickness and the stiffness of the adhesive.

  20. Aerodynamic Problems of Launch Vehicles

    Directory of Open Access Journals (Sweden)

    Kyong Chol Chou


    Full Text Available The airflow along the surface of a launch vehicle together with vase flow of clustered nozzles cause problems which may affect the stability or efficiency of the entire vehicle. The problem may occur when the vehicle is on the launching pad or even during flight. As for such problems, local steady-state loads, overall steady-state loads, buffet, ground wind loads, base heating and rocket-nozzle hinge moments are examined here specifically.

  1. Pet Problems at Home: Pet Problems in the Community. (United States)

    Soltow, Willow


    Discusses problems of pets in the community, examining the community's role related to disruptive pets and pet overpopulation. Also discusses pet problems at home, offering advice on selecting a pet, meeting a pet's needs, and disciplining pets. Includes a list of books, films/filmstrips, teaching materials, and various instructional strategies.…

  2. Problem solving and problem strategies in the teaching and learning ...

    African Journals Online (AJOL)

    Perennial poor performance recorded annually in both internal and external examinations in Mathematics has been a great concern for the Mathematics Educators in Nigeria. This paper discusses problem-solving and influence of problem-solving strategies on students' performance in mathematics. The concept of ...

  3. Inverse feasibility problems of the inverse maximum flow problems

    Indian Academy of Sciences (India)

    199–209. c Indian Academy of Sciences. Inverse feasibility problems of the inverse maximum flow problems. ADRIAN DEACONU. ∗ and ELEONOR CIUREA. Department of Mathematics and Computer Science, Faculty of Mathematics and Informatics, Transilvania University of Brasov, Brasov, Iuliu Maniu st. 50,. Romania.

  4. Eldercare at Home: Communication Problems (United States)

    ... page Related Topics Advance Directives Caregiver Health Cataracts Dementia Glaucoma Guardianship Hearing Loss Managing Multiple Health Problems Nutrition Prevention Stroke Join our e-newsletter! Resources Eldercare at ...

  5. Solving complex fisheries management problems

    DEFF Research Database (Denmark)

    Petter Johnsen, Jahn; Eliasen, Søren Qvist


    A crucial issue for the new EU common fisheries policy is how to solve the discard problem. Through a study of the institutional set up and the arrangements for solving the discard problem in Denmark, the Faroe Islands, Iceland and Norway, the article identifies the discard problem as related to ...... to both natural, other material and to cultural conditions. Hence, solving the discard problem requires not only technical and regulatory instruments, but also arenas and structures that allow and facilitate processes of cultural change....

  6. The ocean circulation inverse problem

    National Research Council Canada - National Science Library

    Wunsch, C


    .... This book addresses the problem of inferring the state of the ocean circulation, understanding it dynamically, and even forecasting it through a quantitative combination of theory and observation...

  7. Sociological interpretation of social problems

    Directory of Open Access Journals (Sweden)

    O. V. Katsora


    The article considers such sociological approaches to social problems as social pathology, social disorganization, functional and critical approaches, the approach of value conflict, constructionsite approach and the approach of «labelling». Each approach has its own peculiarities of consideration of social problems, that is related with the historical period in which it arose and settled down, and the views of members of a particular sociological approach to social problems. Also, the article discusses the main advantages and disadvantages of sociological approaches to dealing the social problems.

  8. Numerical methods problems and solutions

    CERN Document Server

    Jain, MK


    About the Book: Is an outline series containing brief text of numerical solution of transcendental and polynomial equations, system of linear algebraic equations and eigenvalue problems, interpolation and approximation, differentiation and integration, ordinary differential equations and complete solutions to about 300 problems. Most of these problems are given as unsolved problems in the authors earlier book. User friendly Turbo Pascal programs for commonly used numerical methods are given in the Appendix. This book can be used as a text/help book both by teachers and students. Contents:

  9. Problem solving through recreational mathematics

    CERN Document Server

    Averbach, Bonnie


    Historically, many of the most important mathematical concepts arose from problems that were recreational in origin. This book takes advantage of that fact, using recreational mathematics - problems, puzzles and games - to teach students how to think critically. Encouraging active participation rather than just observation, the book focuses less on mathematical results than on how these results can be applied to thinking about problems and solving them. Each chapter contains a diverse array of problems in such areas as logic, number and graph theory, two-player games of strategy, solitaire ga

  10. Problem posing reflections and applications

    CERN Document Server

    Brown, Stephen I


    As a result of the editors' collaborative teaching at Harvard in the late 1960s, they produced a ground-breaking work -- The Art Of Problem Posing -- which related problem posing strategies to the already popular activity of problem solving. It took the concept of problem posing and created strategies for engaging in that activity as a central theme in mathematics education. Based in part upon that work and also upon a number of articles by its authors, other members of the mathematics education community began to apply and expand upon their ideas. This collection of thirty readings is a tes

  11. A university course timetabling problem

    Directory of Open Access Journals (Sweden)

    J.M. Phala


    Full Text Available This paper addresses a university course timetabling problem. The problem as experienced at Unibo is formulated in such a way that simple heuristics can be used to achieve the objective of finding either an 'optimal' or a feasible practical solution. the problem is divided into three phases, namely grouping of courses into course groups, allocation of lecture rooms to courses within groups, and finally, scheduling of periods to course groups. Heuristic algorithms are proposed to solve this problem. The computerised algorithms which have been integrated into Unibo's Student Management System are fully implemented.

  12. Solved problems in classical electromagnetism

    CERN Document Server

    Franklin, Jerrold


    This original Dover publication is the companion to a new edition of the author's Classical Electromagnetism: Second Edition. The latter volume will feature only basic answers; this book will contain some problems from the reissue as well as many other new ones. All feature complete, worked-out solutions and form a valuable source of problem-solving material for students.

  13. Using Logical Problems in ESP. (United States)

    Dorrity, Terry


    A course in scientific English for science researchers and advanced civil engineering students in Belgium has a central problem--the heterogeneous nature of the group and lack of common research experience around which to build a curriculum. An attempt to overcome this difficulty by using two logical problems for discussion is presented. (MSE)

  14. Quantitative Reasoning in Problem Solving (United States)

    Ramful, Ajay; Ho, Siew Yin


    In this article, Ajay Ramful and Siew Yin Ho explain the meaning of quantitative reasoning, describing how it is used in the to solve mathematical problems. They also describe a diagrammatic approach to represent relationships among quantities and provide examples of problems and their solutions.

  15. Geothermal Energy: Prospects and Problems (United States)

    Ritter, William W.


    An examination of geothermal energy as a means of increasing the United States power resources with minimal pollution problems. Developed and planned geothermal-electric power installations around the world, capacities, installation dates, etc., are reviewed. Environmental impact, problems, etc. are discussed. (LK)

  16. A Problem on Optimal Transportation (United States)

    Cechlarova, Katarina


    Mathematical optimization problems are not typical in the classical curriculum of mathematics. In this paper we show how several generalizations of an easy problem on optimal transportation were solved by gifted secondary school pupils in a correspondence mathematical seminar, how they can be used in university courses of linear programming and…

  17. The PPP: Problem Panel Project. (United States)

    Crawford, Russell K.

    The Problem Panel Project is an instructor-developed, one-semester course in contemporary problems. Based on the inquiry approach, the course is structured for independent research and group work and requires no traditionally-structured daily lesson plans. The course is divided into six procedural points. First, students decide which contemporary…

  18. Difficulties in Genetics Problem Solving. (United States)

    Tolman, Richard R.


    Examined problem-solving strategies of 30 high school students as they solved genetics problems. Proposes a new sequence of teaching genetics based on results: meiosis, sex chromosomes, sex determination, sex-linked traits, monohybrid and dihybrid crosses (humans), codominance (humans), and Mendel's pea experiments. (JN)

  19. Problem-Oriented Project Work

    DEFF Research Database (Denmark)

    Olsen, Poul Bitsch; Pedersen, Nils Kaare

    This book is meant to support problem-oriented learning activities. Problem-orientation concerns the reasoning about lack of knowledge, while project work includes the ethnomethods that are practiced when collectives produce scientific knowledge. This book reflects particular methods related...

  20. Problems of the Digestive System (United States)

    ... ASKED QUESTIONS FAQ120 WOMEN’S HEALTH Problems of the Digestive System • What are some common digestive problems? • What is ... of hormones during pregnancy can slow down the digestive system. How can constipation be treated? If constipation continues, ...

  1. School Discipline: Problems Effecting Solutions. (United States)

    Heitzman, Andrew J.; Wiley, David B.


    Failure to solve school discipline problems is attributed to four factors: school district priorities, unclear problem dimensions, inadequate teacher training, and flaws in teacher/ administrator applied psychology. Psychological approaches that provide systems to control student behavior are described, including biophysical, interactionist, and…

  2. Inverse problems for Maxwell's equations

    CERN Document Server

    Romanov, V G


    The Inverse and Ill-Posed Problems Series is a series of monographs publishing postgraduate level information on inverse and ill-posed problems for an international readership of professional scientists and researchers. The series aims to publish works which involve both theory and applications in, e.g., physics, medicine, geophysics, acoustics, electrodynamics, tomography, and ecology.

  3. Coping with persistent environmental problems

    DEFF Research Database (Denmark)

    Varjopuro, Riku; Andrulewicz, Eugeniusz; Brandt, Urs Steiner


    ABSTRACT In this paper we focus on systemic delays in the Baltic Sea that cause the problem of eutrophication to persist. These problems are demonstrated in our study by addressing three types of delays: (1) decision delay: the time it takes for an idea or perceived need to be launched as a polic...

  4. Vaccination and the prevention problem. (United States)

    Dawson, Angus


    This paper seeks to critically review a traditional objection to preventive medicine (which I call here the 'prevention problem'). The prevention problem is a concern about the supposedly inequitable distribution of benefits and risks of harm resulting from preventive medicine's focus on population-based interventions. This objection is potentially applicable to preventive vaccination programmes and could be used to argue that such programmes are unethical. I explore the structure of the prevention problem by focusing upon two different types of vaccination (therapeutic vaccination and preventive vaccination). I argue that the 'prevention problem' cannot be fairly applied to the case of preventive vaccination because such programmes do not just focus upon benefits at the level of populations (as is claimed by the prevention problem). Most such preventive vaccination programmes explicitly seek to create and maintain herd protection. I argue that herd protection is an important public good which is a benefit shared by all individuals in the relevant population. This fact can then be used to block the 'prevention problem' argument in relation to preventive vaccination programmes. I conclude by suggesting that whilst the future development and use of therapeutic vaccines does raise some interesting ethical issues, any ethical objections to prophylactic vaccination on the basis of the 'prevention problem' will not be overcome through the substitution of therapeutic vaccines for preventive vaccines; indeed, the 'prevention problem' fails on its own terms in relation to preventive vaccination programmes.

  5. On the Chern Yamabe Problem

    DEFF Research Database (Denmark)

    Angella, Daniele; Calamai, Simone; Spotti, Cristiano


    We undertake the study of an analogue of the Yamabe problem for complex manifolds. More precisely, for any conformal Hermitian structure on a compact complex manifold, we are concerned in the existence of metrics with constant Chern scalar curvature. In this note, we set the problem and we provid...

  6. Traveling Salesman Problem with Transportation

    Directory of Open Access Journals (Sweden)

    Valeriu Ungureanu


    Full Text Available Traveling Salesman Problem (TSP is a generic name that includes diverse practical models. Motivated by applications, a new model of TSP is examined – a synthesis of classical TSP and classical Transportation Problem. Algorithms based on Integer Programming cutting-plane methods and Branch and Bound Techniques are obvious.

  7. Combinatorial reasoning to solve problems

    NARCIS (Netherlands)

    Coenen, Tom Johannes Maria; Hof, Frits; Verhoef, Neeltje Cornelia


    This study reports combinatorial reasoning to solve problems. We observed the mathematical thinking of students aged 14-16. We study the variation of the students’ solution strategies in the context of emergent modelling. The results show that the students are tempted to begin the problem solving

  8. Scalable algorithms for contact problems

    CERN Document Server

    Dostál, Zdeněk; Sadowská, Marie; Vondrák, Vít


    This book presents a comprehensive and self-contained treatment of the authors’ newly developed scalable algorithms for the solutions of multibody contact problems of linear elasticity. The brand new feature of these algorithms is theoretically supported numerical scalability and parallel scalability demonstrated on problems discretized by billions of degrees of freedom. The theory supports solving multibody frictionless contact problems, contact problems with possibly orthotropic Tresca’s friction, and transient contact problems. It covers BEM discretization, jumping coefficients, floating bodies, mortar non-penetration conditions, etc. The exposition is divided into four parts, the first of which reviews appropriate facets of linear algebra, optimization, and analysis. The most important algorithms and optimality results are presented in the third part of the volume. The presentation is complete, including continuous formulation, discretization, decomposition, optimality results, and numerical experimen...

  9. Math word problems for dummies

    CERN Document Server

    Sterling, Mary Jane


    Covers percentages, probability, proportions, and moreGet a grip on all types of word problems by applying them to real lifeAre you mystified by math word problems? This easy-to-understand guide shows you how to conquer these tricky questions with a step-by-step plan for finding the right solution each and every time, no matter the kind or level of problem. From learning math lingo and performing operations to calculating formulas and writing equations, you''ll get all the skills you need to succeed!Discover how to: * Translate word problems into plain English* Brush up on basic math skills* Plug in the right operation or formula* Tackle algebraic and geometric problems* Check your answers to see if they work

  10. Methods of solving nonstandard problems

    CERN Document Server

    Grigorieva, Ellina


    This book, written by an accomplished female mathematician, is the second to explore nonstandard mathematical problems – those that are not directly solved by standard mathematical methods but instead rely on insight and the synthesis of a variety of mathematical ideas.   It promotes mental activity as well as greater mathematical skills, and is an ideal resource for successful preparation for the mathematics Olympiad. Numerous strategies and techniques are presented that can be used to solve intriguing and challenging problems of the type often found in competitions.  The author uses a friendly, non-intimidating approach to emphasize connections between different fields of mathematics and often proposes several different ways to attack the same problem.  Topics covered include functions and their properties, polynomials, trigonometric and transcendental equations and inequalities, optimization, differential equations, nonlinear systems, and word problems.   Over 360 problems are included with hints, ...

  11. The three-body problem. (United States)

    Musielak, Z E; Quarles, B


    The three-body problem, which describes three masses interacting through Newtonian gravity without any restrictions imposed on the initial positions and velocities of these masses, has attracted the attention of many scientists for more than 300 years. In this paper, we present a review of the three-body problem in the context of both historical and modern developments. We describe the general and restricted (circular and elliptic) three-body problems, different analytical and numerical methods of finding solutions, methods for performing stability analysis and searching for periodic orbits and resonances. We apply the results to some interesting problems of celestial mechanics. We also provide a brief presentation of the general and restricted relativistic three-body problems, and discuss their astronomical applications.

  12. Statistical perspectives on inverse problems

    DEFF Research Database (Denmark)

    Andersen, Kim Emil

    of the interior of an object from electrical boundary measurements. One part of this thesis concerns statistical approaches for solving, possibly non-linear, inverse problems. Thus inverse problems are recasted in a form suitable for statistical inference. In particular, a Bayesian approach for regularisation...... problem is given in terms of probability distributions. Posterior inference is obtained by Markov chain Monte Carlo methods and new, powerful simulation techniques based on e.g. coupled Markov chains and simulated tempering is developed to improve the computational efficiency of the overall simulation......Inverse problems arise in many scientific disciplines and pertain to situations where inference is to be made about a particular phenomenon from indirect measurements. A typical example, arising in diffusion tomography, is the inverse boundary value problem for non-invasive reconstruction...

  13. Solving applied mathematical problems with Matlab

    CERN Document Server

    Xue, Dingyu


    Computer Mathematics Language-An Overview. Fundamentals of MATLAB Programming. Calculus Problems. MATLAB Computations of Linear Algebra Problems. Integral Transforms and Complex Variable Functions. Solutions to Nonlinear Equations and Optimization Problems. MATLAB Solutions to Differential Equation Problems. Solving Interpolations and Approximations Problems. Solving Probability and Mathematical Statistics Problems. Nontraditional Solution Methods for Mathematical Problems.

  14. Generating clustered scale-free networks using Poisson based localization of edges (United States)

    Türker, İlker


    We introduce a variety of network models using a Poisson-based edge localization strategy, which result in clustered scale-free topologies. We first verify the success of our localization strategy by realizing a variant of the well-known Watts-Strogatz model with an inverse approach, implying a small-world regime of rewiring from a random network through a regular one. We then apply the rewiring strategy to a pure Barabasi-Albert model and successfully achieve a small-world regime, with a limited capacity of scale-free property. To imitate the high clustering property of scale-free networks with higher accuracy, we adapted the Poisson-based wiring strategy to a growing network with the ingredients of both preferential attachment and local connectivity. To achieve the collocation of these properties, we used a routine of flattening the edges array, sorting it, and applying a mixing procedure to assemble both global connections with preferential attachment and local clusters. As a result, we achieved clustered scale-free networks with a computational fashion, diverging from the recent studies by following a simple but efficient approach.

  15. Problem Solving Reasoning and Problem Based Instruction in Geometry Learning (United States)

    Sulistyowati, F.; Budiyono, B.; Slamet, I.


    This research aims to analyze the comparison Problem Solving Reasoning (PSR) and Problem Based Instruction (PBI) on problem solving and mathematical communication abilities viewed from Self-Regulated Learning (SRL). Learning was given to grade 8th junior high school students. This research uses quasi experimental method, and then with descriptive analysis. Data were analyzed using two-ways multivariate analysis of variance (MANOVA) and one-way analysis of variance (ANOVA) with different cells. The result of data analysis were learning model gives different effect, level of SRL gives the same effect, and there is no interaction between the learning model with the SRL on the problem solving and mathematical communication abilities. The t-test statistic was used to find out more effective learning model. Based on the test, regardless of the level of SRL, PSR is more effective than PBI for problemsolving ability. The result of descriptive analysis was PSR had the advantage in creating learning that optimizing the ability of learners in reasoning to solve a mathematical problem. Consequently, the PSR is the right learning model to be applied in the classroom to improve problem solving ability of learners.

  16. Youth employment problems in Latvia


    Mičule, Madara


    Unemployment to which young people are also subjected, is one of the main economical problems nowadays. The issue is actual also for Latvian youth. Therefore the theme of the Bachelor’s work is „Youth unemployment problems in Latvia”. The aim of the Bachelor’s work is to find out the current situation in the unemployment sphere, young people’s employment in Latvia as well as to work out solutions which could be used to solve the problem. The unemployment term, its types, causes and ef...

  17. The Soccer-Ball Problem (United States)

    Hossenfelder, Sabine


    The idea that Lorentz-symmetry in momentum space could be modified but still remain observer-independent has received quite some attention in the recent years. This modified Lorentz-symmetry, which has been argued to arise in Loop Quantum Gravity, is being used as a phenomenological model to test possibly observable effects of quantum gravity. The most pressing problem in these models is the treatment of multi-particle states, known as the 'soccer-ball problem'. This article briefly reviews the problem and the status of existing solution attempts.

  18. Customer-centered problem solving. (United States)

    Samelson, Q B


    If there is no single best way to attract new customers and retain current customers, there is surely an easy way to lose them: fail to solve the problems that arise in nearly every buyer-supplier relationship, or solve them in an unsatisfactory manner. Yet, all too frequently, companies do just that. Either we deny that a problem exists, we exert all our efforts to pin the blame elsewhere, or we "Band-Aid" the problem instead of fixing it, almost guaranteeing that we will face it again and again.

  19. Problems of multiphase fluid filtration

    CERN Document Server

    Konovalov, AN


    This book deals with a spectrum of problems related to the mathematical modeling of multiphase filtration. Emphasis is placed on an inseparable triad: model - algorithm - computer code. An analysis of new and traditional filtration problems from the point of view of both their numerical implementation and the reproduction of one or another technological characteristics of the processes under consideration is given. The basic principles which underlie the construction of efficient numerical methods taking into account the filtration problems are discussed: non-evolutionary nature, degeneration,

  20. Problem Based Learning and sustainability

    DEFF Research Database (Denmark)

    Pizzol, Massimo; Løkke, Søren; Schmidt, Jannick Højrup

    Problem-Based Learning (PBL) is a style of active learning based on problem solving. PBL aims at providing university students with flexible knowledge, capacity to self-learning, and skills in problem solving and collaboration. In this context, the present study explores the advantages...... University (AAU), Denmark, and focuses on the teaching of Life Cycle Assessment as a method for sustainability assessment. The objective is providing recommendations for future LCA teaching and learning. PBL activites performed at AAU were evaluated critically to detemine to what extent they addressed...

  1. Developmental Problems and Dental Morphology (United States)

    Goodwin, William C., Jr.; Erickson, Marilyn T.


    Ninety-five subjects (mean age 55 months) with mental retardation, learning disabilities, and/or minimal brain dysfunction and 47 control subjects (mean age 46 months) were compared to determine the relationship between developmental problems and dental morphology. (Author)

  2. Parameter estimation and inverse problems

    CERN Document Server

    Aster, Richard C; Thurber, Clifford H


    Parameter Estimation and Inverse Problems primarily serves as a textbook for advanced undergraduate and introductory graduate courses. Class notes have been developed and reside on the World Wide Web for faciliting use and feedback by teaching colleagues. The authors'' treatment promotes an understanding of fundamental and practical issus associated with parameter fitting and inverse problems including basic theory of inverse problems, statistical issues, computational issues, and an understanding of how to analyze the success and limitations of solutions to these probles. The text is also a practical resource for general students and professional researchers, where techniques and concepts can be readily picked up on a chapter-by-chapter basis.Parameter Estimation and Inverse Problems is structured around a course at New Mexico Tech and is designed to be accessible to typical graduate students in the physical sciences who may not have an extensive mathematical background. It is accompanied by a Web site that...

  3. Fuel cells: Problems and prospects


    Shukla, AK; Ramesh, KV; Kannan, AM


    n recent years, fuel cell technology has advanced significantly. Field trials on certain types of fuel cells have shown promise for electrical use. This article reviews the electrochemistry, problems and prospects of fuel cell systems.

  4. Problems in Recording the Electrocardiogram. (United States)

    Webster, John G.

    The unwanted signals that arise in electrocardiography are discussed. A technical background of electrocardiography is given, along with teaching techniques that educate students of medical instrumentation to solve the problems caused by these signals. (MJH)

  5. Ingenious mathematical problems and methods

    CERN Document Server

    Graham, Louis A


    Collection of 100 of the best submissions to a math puzzle column features problems in engineering situations, logic, number theory, and geometry. Most solutions include details of several different methods.

  6. Direct channel problems and phenomena

    International Nuclear Information System (INIS)

    Cutkosky, R.E.


    Direct channel problems and phenomena are considered covering the need for precision hadron spectroscopy, the data base for precision hadron spectroscopy, some relations between direct-channel and cross-channel effects, and spin rotation phenomena

  7. Bladder Control Problems in Women (United States)

    ... be affected than Hispanic/Latina, African American, or Asian American women UI is not a disease. UI ... a UTI, a kidney problem, or diabetes. Urine culture. A health care professional performs a urine culture ...

  8. Fathers and preschool behavior problems. (United States)

    DeKlyen, M; Biernbaum, M A; Speltz, M L; Greenberg, M T


    Fathers have seldom been the focus of research investigating the causes and correlates of early behavior problems. Two studies examined fathers of preschool boys with and without clinic-referred behavior problems. Six domains of risk were examined: life stress, social support, psychological symptoms, parenting attitudes, positive involvement, and harsh discipline. Clinic fathers differed from fathers of matched comparison boys with respect to all of these except social support, but only harsh discipline contributed uniquely to clinic status. These domains correctly classified 81% of the boys. Within the clinic group, teacher-rated problem severity 1 year later was predicted by fathers' life stress, psychological symptoms, and positive involvement, indicating that different factors may account for initial clinic status versus stability of problems. Mothers' self-report data better predicted clinic group membership, whereas fathers' data better predicted Year 2 outcomes for clinic boys.

  9. Learning problems in neurofibromatosis patients. (United States)

    Stine, S B; Adams, W V


    Learning problems in patients with neurofibromatosis (NF) are probably the most frequent characteristics after those that define the disorder. They are not secondary to the physical problems. A recent survey that compared children who have NF with their siblings revealed a 37% greater incidence of learning disabilities in the children with NF. Intelligence quotient (IQ) data from several studies indicate that almost all patients with NF have a normal IQ, but there is a progression from low normal to normal as these patients reach adulthood. The most common psychoeducational problems include visual-perceptual-motor delay, spelling and arithmetic disabilities, and a cluster of weaknesses related to cortical organization, similar to those seen in children with attention-deficit disorders. A type of learning disability unique to patients with NF has not been identified, and the diagnosis and treatment of the learning problems are generally the same as for children without NF.

  10. Enteral nutrition - child - managing problems (United States)

    ... page: // Enteral nutrition - child - managing problems To use the sharing features ... trouble breathing, call 911. References Mcclave SA. Enteral nutrition. In: Goldman L, Schafer AI, eds. Goldman-Cecil ...

  11. Mathematical problems of electromagnetoelastic interactions

    Directory of Open Access Journals (Sweden)

    Mikhail Vishnevskii


    Full Text Available There are studied nonlinear mathematical problems of the interactionof electromagnetic fields with deformable media. The models are based on combination of the Lam and Maxwell systems coupled through so-called seismomagnetic effect. Several direct and associated with them inverse problems are studied. Then speaking about the inverse problems, electromagnetic and elastic characteristics of a medium are the subject of reconstruction. The values of physical fields are connected through electromagnetoelastic interactions. We consider the processes which are observed when elastic waves propagate in an elastic electroconducting medium. Variations of the seismic and electromagnetic fields in this case are called electro-magnetoelastic waves. There are described di®erent statements of mathematical model of the electromagnetoelastic interactions. Then the theoretical results of the analytical solution are discussed for various nonlinear direct and inverse problems for the equations of electromagnetoelasticity.

  12. Who matters in coordination problems?

    Czech Academy of Sciences Publication Activity Database

    Sákovics, J.; Steiner, Jakub


    Roč. 102, č. 7 (2012), s. 3439-3461 ISSN 0002-8282 Institutional support: RVO:67985998 Keywords : coordination problem s * heterogeneous agents Subject RIV: AH - Economics Impact factor: 2.792, year: 2012

  13. COPD and other health problems (United States)

    ... this page: // COPD and other health problems To use the sharing ... diabetes, and high blood pressure. Staying Healthy With COPD Work closely with your doctor to keep COPD ...

  14. Progressive problems higher grade physics

    CERN Document Server

    Kennedy, William


    This book fully covers all three Units studied in Scotland's Higher Grade Physics course, providing a systematic array of problems (from the simplest to the most difficult) to lead variously abled pupils to examination success.

  15. Uncapacitated facility location problems: contributions

    Directory of Open Access Journals (Sweden)

    Galvão Roberto Diéguez


    Full Text Available The objective of the present paper is to review my personal contributions in the field of uncapacitated facility location problems. These contributions took place throughout my academic career, from the time I was a Ph.D. student at Imperial College to the present day. They cover approximately 30 years, from 1973 to 2003; they address: algorithms developed for the p-median problem and for a general formulation of uncapacitated location problems; the study of dynamic location models; covering and hierarchical location problems; queuing-based probabilistic location models. The contributions encompass theoretical developments, computational algorithms and practical applications. All work took place in an academic environment, with the invaluable collaboration of colleagues (both in Brazil and abroad and research students at COPPE. Each section in the paper is dedicated to a topic that involves a personal contribution. Every one of them is placed within the context of the existing literature.

  16. Attentional biases in problem and non-problem gamblers. (United States)

    Ciccarelli, Maria; Nigro, Giovanna; Griffiths, Mark D; Cosenza, Marina; D'Olimpio, Francesca


    From a cognitive perspective, attentional biases are deemed as factors responsible in the onset and development of gambling disorder. However, knowledge relating to attentional processes in gambling is scarce and studies to date have reported contrasting results. Moreover, no study has ever examined which component and what type of bias are involved in attentional bias in gambling. In the present study, 108 Italian participants, equally divided into problem and non-problem gamblers, were administered a modified Posner Task, an attentional paradigm in which - through the manipulation of stimuli presentation time - it is possible to measure both initial orienting and maintenance of attention. In addition to the experimental task, participants completed self-report measures involving (i) craving (Gambling Craving Scale), (ii) depression, anxiety and stress (Depression Anxiety Stress Scale) and (iii) emotional dysregulation (Difficulties in Emotion Regulation Scale). Analyses revealed facilitation in detecting gambling-related stimuli at the encoding level in problem gamblers but not in non-problem gamblers. Compared to non-problem gamblers, problem gamblers also reported higher levels of craving, emotional dysregulation, and negative mood states. Furthermore, all measures correlated with the gambling severity. The use of indirect measure of attentional bias could be less accurate compared to direct measures. The facilitation in detecting gambling-related stimuli in problem gamblers and the correlation between subjective craving and facilitation bias suggests that attentional bias could not be due to a conditioning process but that motivational factors such as craving could induce addicted-related seeking-behaviors. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. The problem of Newton dynamics

    International Nuclear Information System (INIS)

    Roman Roldan, R.


    The problem of the teaching of Newton's principles of dynamics at High School level is addressed. Some usages, reasoning and wording, are pointed as the responsible for the deficient results which are revealed in the background of the first year University students in Physics. A methodology based on simplifying the common vocabulary is proposed in order to provide to the students with a clearer view of the dynamic problems. Some typical examples are shown which illustrate the proposal. (Author)

  18. Example Problems in LES Combustion (United States)


    memorandum is the evaporation and subsequent combustion of liquid fuel droplets. Kerosene, a complex hydrogen mixture, is explored from the standpoint of...AFRL-RW-EG-TP-2016-002 Example Problems in LES Combustion Douglas V. Nance Air Force Research Laboratory Munitions...4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Example Problem in LES Combustion 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER

  19. Wicksell's Problem in Local Stereology

    DEFF Research Database (Denmark)

    Thórisdóttir, Ólöf; Kiderlen, Markus

    Wicksell's classical corpuscle problem deals with the retrieval of the size distribution of spherical particles from planar sections. We discuss the problem in a local stereology framework. Each particle is assumed to contain a reference point and the individual particle is sampled...... and particle parameters, unfolding of the arising integral equations, uniqueness issues and domain of attraction relations are discussed. We illustrate the approach by reconstructing from simulated data using numerical unfolding algorithms....

  20. Leadership as a Design Problem (United States)


    Organizational Behavior and Human Performance, 1975, U, 264-280. Bennis, W. G. Leadership theory and administrative behavior: The problem of authority...Administrative Science Quarterly, 1959, 4, 259-301^ Calder, B. J. An attribution theory of leadership . In B. Staw & G, Salancik (Eds.), New directions...REPORT NUMBER TR #1 2. GOVT ACCESSION NO 3. RECIPIENT’S CATALOG NUMBER 4. TITLE (and Sublllle) LEADERSHIP AS A DESIGN PROBLEM 5

  1. Spent nuclear fuel transport problems

    International Nuclear Information System (INIS)

    Kondrat'ev, A.N.; Kosarev, Yu.A.; Yulikov, E.I.


    The paper considers the problems of shipping spent fuel from nuclear power stations to reprocessing plants and also the principal ways of solving these problems with a view to achieving maximum economy and safety in transport. The increase in the number of nuclear power plants in the USSR will entail an intensification of spent-fuel shipments. Higher burnup and the need to reduce cooling time call for heavier and more complex shipping containers. The problem of shipping spent fuel should be tackled comprehensively, bearing in mind the requirements of safety and economy. One solution to these problems is to develop rational and cheap designs of such containers. In addition, the world-wide trend towards more thorough protection of the environment against pollution and of the health of the population requires the devotion of constant attention to improving the reliability and safety of shipments. The paper considers the prospects for nuclear power development in the USSR and in other member countries of the CMEA (1976-1980), the composition and design of some Soviet packaging assemblies, the appropriate cooling time for spent fuel from thermal reactor power stations, procedures for reducing fuel-shipping costs, some methodological problems of container calculation and design, and finally problems of testing and checking containers on test rigs. (author)


    Directory of Open Access Journals (Sweden)

    V. Kushnir


    Full Text Available The tasks of integrative content requires the use of knowledge and skills on various themes both one discipline and different disciplines. Mostly in the classroom (or in homework the tasks on the properties absorption of different concepts using different theories are considered. Thus knowledge within only one discipline is formed, knowledge of the narrow sense (one subject. Such knowledge is "prescriptional", we call it idealized. After all, it is far from models of the real professional problems and problems of life in general, in order to solve them it is necessary to apply knowledge and skills acquired in different themes of the same objects,life experience. Practical formation of integrative knowledge requires statement of the educational problems before the subjects of studying, the problems within the "narrow objectivity" can not be resolved at all, or such kind of solving is too difficult to solve, for example, the nature and the context of solving problems (scientific approaches to solving problems, creating mathematical models, methods for solving such models, means of solving, application of methods, analysis of the models solution and the right choice, the inspection of solutions, etc. will sink in the conglomeration of technical operations. The problems with integrative content are usually more complicated than the problems of "narrow objectivity." In our problems the index of such difficulty is the essence of educational content, which is disclosed in the previous paragraph. The problems solution proposed in this article requires knowledge of the structural geometry (circle construction, touching two or three laps: with analytic geometry (method of coordinates on the plane; the distance between two points on the coordinate plane; algebra (system drawing irrational equations, method for solving such system, the solution of the system, analysis of the results and the right choose of the desired solution for found criterion, testing

  3. Aging and skilled problem solving. (United States)

    Charness, N


    Information-processing models of problem solving too often are based on restrictive age ranges. On the other hand, gerontologists have investigated few problem-solving tasks and have rarely generated explicit models. As this article demonstrates, both fields can benefit by closer collaboration. One major issue in gerontology is whether aging is associated with irreversible decrement or developmental plasticity. If both processes occur, then an appropriate strategy for investigating aging is to equate age groups for molar problem-solving performance and search for differences in the underlying components. This strategy was adopted to examine the relation of age and skill to problem solving in chess. Chess players were selected to vary widely in age and skill such that these variables were uncorrelated. Problem-solving and memory tasks were administered. Skill level was the only significant predictor for accuracy in both a choose-a-move task and a speeded end-game evaluation task. Age (negatively) and skill (positively) jointly determined performance in an unexpected recall task. Efficient chunking in recall was positively related to skill, though negatively related to age. Recognition confidence, though not accuracy, was negatively related to age. Thus despite age-related declines in encoding and retrieval of information, older players match the problem-solving performance of equivalently skilled younger players. Apparently, they can search the problem space more efficiently, as evidenced by taking less time to select an equally good move. Models of chess skill that stress that role of encoding efficiency, as indexed by chunking in recall, need to be modified to account for performance over the life span.

  4. Existence results for trifunction equilibrium problems and fixed point problems (United States)

    Mahato, Nihar Kumar; Noor, Muhammad Aslam; Sahu, Nabin Kumar


    In this paper, we establish the existence and uniqueness solutions of trifunction equilibrium problems using the generalized relaxed α -monotonicity in Banach spaces. By using the generalized f-projection operator, a hybrid iteration scheme is presented to find a common element of the solutions of a system of trifunction equilibrium problems and the set of fixed points of an infinite family of quasi-φ -nonexpansive mappings. Moreover, the strong convergence of our new proposed iterative method under generalized relaxed α -monotonicity is considered.

  5. Interpersonal problems in eating disorders. (United States)

    Hartmann, Armin; Zeeck, Almut; Barrett, Marna S


    Eating disorders are often chronic in nature and lead to a number of problems among which interpersonal issues are suggested to be central. Although research has shown that individuals with disturbed patterns of eating consistently report problems in social interactions, this study is unique in assessing a range of interpersonal problems among patients with all types of eating disorders before and after intensive hospital-based treatment. A total of 208 patients receiving a primary diagnosis of restrictive anorexia nervosa, bulimia nervosa, or anorexia nervosa of the binge/purging-subtype were included in the study. Eating pathology, symptom severity, and interpersonal patterns were examined before and after treatment. Patients with eating disorders exhibited a generally nonassertive, submissive interpersonal style, with anorexic patients of the binge/purging-subtype reporting more difficulties with social inhibition and nonaffiliation. These patterns were found to change over the course of treatment with interpersonal problems at intake predictive of greater binge severity at discharge. Furthermore, issues of dominance and social avoidance predicted outcome for specific subgroups of patients. Results underscore the importance of interpersonal problems in eating disorders and suggest that interpersonal patterns remain a focus of treatment and future research. © 2009 by Wiley Periodicals, Inc.

  6. Computational problems in Arctic Research

    International Nuclear Information System (INIS)

    Petrov, I


    This article is to inform about main problems in the area of Arctic shelf seismic prospecting and exploitation of the Northern Sea Route: simulation of the interaction of different ice formations (icebergs, hummocks, and drifting ice floes) with fixed ice-resistant platforms; simulation of the interaction of icebreakers and ice- class vessels with ice formations; modeling of the impact of the ice formations on the underground pipelines; neutralization of damage for fixed and mobile offshore industrial structures from ice formations; calculation of the strength of the ground pipelines; transportation of hydrocarbons by pipeline; the problem of migration of large ice formations; modeling of the formation of ice hummocks on ice-resistant stationary platform; calculation the stability of fixed platforms; calculation dynamic processes in the water and air of the Arctic with the processing of data and its use to predict the dynamics of ice conditions; simulation of the formation of large icebergs, hummocks, large ice platforms; calculation of ridging in the dynamics of sea ice; direct and inverse problems of seismic prospecting in the Arctic; direct and inverse problems of electromagnetic prospecting of the Arctic. All these problems could be solved by up-to-date numerical methods, for example, using grid-characteristic method. (paper)

  7. High intensity heat pulse problem

    International Nuclear Information System (INIS)

    Yalamanchili, R.


    The use of finite-difference methods for the solution of partial differential equations is common in both design and research and development because of the advance of computers. The numerical methods for the unsteady heat diffusion equation received most attention not only because of heat transfer problems but also happened to be the basis for any study of parabolic partial differential equations. It is common to test the heat equation first even the methods developed for complex nonlinear parabolic partial differential equations arising in fluid mechanics or convective heat transfer. It is concluded that the finite-element method is conservative in both stability and monoscillation characteristics than the finite-difference method but not as conservative as the method of weighted-residuals. Since the finite-element is unique because of Gurtin's variational principle and numerous finite-differences can be constructed, it is found that some finite-difference schemes are better than the finite-element scheme in accuracy also. Therefore, further attention is focused here on finite-difference schemes only. Various physical problems are considered in the field of heat transfer. These include: numerous problems in steady and unsteady heat conduction; heat pulse problems, such as, plasma torch; problems arising from machining operations, such as, abrasive cut-off and surface grinding. (Auth.)

  8. Urban-Rural Problems. Contemporary Social Problems Series. (United States)

    Taylor, Lee

    Various social problems are created by migration of low-income rural people into urban areas. These people are classified "low income" because their material level-of-living is often less than that found in urban areas. The dominant national values for material well-being are based upon urban middle class standards, thus creating a social problem…

  9. Solving Optimization Problems with Dynamic Geometry Software: The Airport Problem (United States)

    Contreras, José


    This paper describes how the author's students (in-service and pre-service secondary mathematics teachers) enrolled in college geometry courses use the Geometers' Sketchpad (GSP) to gain insight to formulate, confirm, test, and refine conjectures to solve the classical airport problem for triangles. The students are then provided with strategic…

  10. The Problem with Theory Is the Problem with Practice. (United States)

    Otte, George

    When composition educators talk about either "theory" or "practice," they are not referring to a monolithic and unified field, but instead to any number of competing, ideologically charged metacommentaries. The "problem with practice" refers to its own socially complex and temporally diffuse nature. Applications of…

  11. OPEN PROBLEM: Some problems in differential geometry and topology (United States)

    Donaldson, S. K.


    This does not attempt to be a systematic overview or to present a comprehensive list of problems. We outline some questions in three different areas which seem interesting to the author. Experts will learn little that is new; our goal is to give some picture of the fields for non-specialists.

  12. Food irradiation - Problems and promises

    International Nuclear Information System (INIS)

    Hickman, J.R.


    It has been stated that food irradiation represents the most significant discovery in food processing since Nicholas Appert invented canning in 1810. Certainly it is a process with great future potential; it is attractive because it works without heating the product, it is effective within sealed containers as well as for bulk usage, and it does not leave chemical residues on the treated food. Of course, no one process can be expected to solve all problems relating to preservation of food. Ionizing radiation can be used effectively to solve many of these problems, but the process is no panacea to cure the world's food problems. Unfortunately, early ill-founded claims about irradiation led to expectations which have proved beyond the reasonable capabilities of the process. Nevertheless, the number of foods that have been successfully treated, and the broad range of effects that can be achieved by radiation processing is impressive. (author)

  13. Bernoulli Variational Problem and Beyond

    KAUST Repository

    Lorz, Alexander


    The question of \\'cutting the tail\\' of the solution of an elliptic equation arises naturally in several contexts and leads to a singular perturbation problem under the form of a strong cut-off. We consider both the PDE with a drift and the symmetric case where a variational problem can be stated. It is known that, in both cases, the same critical scale arises for the size of the singular perturbation. More interesting is that in both cases another critical parameter (of order one) arises that decides when the limiting behaviour is non-degenerate. We study both theoretically and numerically the values of this critical parameter and, in the symmetric case, ask if the variational solution leads to the same value as for the maximal solution of the PDE. Finally we propose a weak formulation of the limiting Bernoulli problem which incorporates both Dirichlet and Neumann boundary condition. © 2013 Springer-Verlag Berlin Heidelberg.

  14. Dealing with the problem countries

    International Nuclear Information System (INIS)

    Jones, R.W.


    The test of America's policies to prevent nuclear proliferation is the so-called problem countries, those states that pose the greatest risk of ''going nuclear.'' Most visible - and the source of greatest concern - are those countries which have developed or appear to be in the process of developing nuclear weapons capabilities. In addition to Pakistan, near-nuclear countries of note include India, Israel, South Africa, Argentina, South Korea, and Taiwan. Several other countries, including Iraq, Iran, Libya, and Brazil, seem to pose proliferation risks in the longer term. More problematic are countries, such as Mexico, that, although they seem to represent little or no proliferation risk themselves, pose difficult problems by challenging restrictions in nuclear export policy. The author examines US policy toward some of the problem countries, paying particular attention to Pakistan. The constants in US policy and the few changes wrought by the Reagan administration are noted throughout

  15. Axisymmetric finite deformation membrane problems

    Energy Technology Data Exchange (ETDEWEB)

    Feng, W.W.


    Many biomechanic problems involve the analysis of finite deformation axisymmetric membranes. This paper presents the general formulation for solving a class of axisymmetric membrane problems. The material nonlinearity, as well as the geometric nonlinearity, is considered. Two methods are presented to solve these problems. The first method is solving a set of differential equilibrium equations. The governing equations are reduced to three first-order ordinary-differential equations with explicit derivatives. The second method is the Ritz method where a general potential energy functional valid for all axisymmetric deformed positions is presented. The geometric admissible functions that govern the deformed configuration are written in terms of a series with unknown coefficients. These unknown coefficients are determined by the minimum potential energy principle that of all geometric admissible deformed configurations, the equilibrium configuration minimizes the potential energy. Some examples are presented. A comparison between these two methods is mentioned.

  16. Problems in structural inorganic chemistry

    CERN Document Server

    Li, Wai-Kee; Mak, Thomas Chung Wai; Mak, Kendrew Kin Wah


    This book consists of over 300 problems (and their solutions) in structural inorganic chemistry at the senior undergraduate and beginning graduate level. The topics covered comprise Atomic and Molecular Electronic States, Atomic Orbitals, Hybrid Orbitals, Molecular Symmetry, Molecular Geometry and Bonding, Crystal Field Theory, Molecular Orbital Theory, Vibrational Spectroscopy, and Crystal Structure. The central theme running through these topics is symmetry, molecular or crystalline. The problems collected in this volume originate in examination papers and take-home assignments that have been part of the teaching of the book's two senior authors' at The Chinese University of Hong Kong over the past four decades. The authors' courses include Chemical Bonding, Elementary Quantum Chemistry, Advanced Inorganic Chemistry, X-Ray Crystallography, etc. The problems have been tested by generations of students taking these courses.

  17. Java problem-based learning

    Directory of Open Access Journals (Sweden)

    Goran P, Šimić


    Full Text Available The paper describes the self-directed problem-based learning system (PBL named Java PBL. The expert module is the kernel of Java PBL. It involves a specific domain model, a problem generator and a solution generator. The overall system architecture is represented in the paper. Java PBL can act as the stand-alone system, but it is also designed to provide support to learning management systems (LMSs. This is provided by a modular design of the system. An LMS can offer the declarative knowledge only. Java PBL offers the procedural knowledge and the progress of the learner programming skills. The free navigation, unlimited numbers of problems and recommendations represent the main pedagogical strategies and tactics implemented into the system.

  18. Image Processing: Some Challenging Problems (United States)

    Huang, T. S.; Aizawa, K.


    Image processing can be broadly defined as the manipulation of signals which are inherently multidimensional. The most common such signals are photographs and video sequences. The goals of processing or manipulation can be (i) compression for storage or transmission; (ii) enhancement or restoration; (iii) analysis, recognition, and understanding; or (iv) visualization for human observers. The use of image processing techniques has become almost ubiquitous; they find applications in such diverse areas as astronomy, archaeology, medicine, video communication, and electronic games. Nonetheless, many important problems in image processing remain unsolved. It is the goal of this paper to discuss some of these challenging problems. In Section I, we mention a number of outstanding problems. Then, in the remainder of this paper, we concentrate on one of them: very-low-bit-rate video compression. This is chosen because it involves almost all aspects of image processing.

  19. Modern problems in applied analysis

    CERN Document Server

    Rogosin, Sergei


    This book features a collection of recent findings in Applied Real and Complex Analysis that were presented at the 3rd International Conference “Boundary Value Problems, Functional Equations and Applications” (BAF-3), held in Rzeszow, Poland on 20-23 April 2016. The contributions presented here develop a technique related to the scope of the workshop and touching on the fields of differential and functional equations, complex and real analysis, with a special emphasis on topics related to boundary value problems. Further, the papers discuss various applications of the technique, mainly in solid mechanics (crack propagation, conductivity of composite materials), biomechanics (viscoelastic behavior of the periodontal ligament, modeling of swarms) and fluid dynamics (Stokes and Brinkman type flows, Hele-Shaw type flows). The book is addressed to all readers who are interested in the development and application of innovative research results that can help solve theoretical and real-world problems.

  20. Linear and complex analysis problem

    CERN Document Server

    Nikolski, Nikolai


    The 2-volume book is an updated, reorganized and considerably enlarged version of the previous edition of the Research Problem Book in Analysis (LNM 1043), a collection familiar to many analysts, that has sparked off much research. This new edition, created in a joint effort by a large team of analysts, is, like its predecessor, a collection of unsolved problems of modern analysis designed as informally written mini-articles, each containing not only a statement of a problem but also historical and methodological comments, motivation, conjectures and discussion of possible connections, of plausible approaches as well as a list of references. There are now 342 of these mini- articles, almost twice as many as in the previous edition, despite the fact that a good deal of them have been solved!

  1. Linear and complex analysis problem

    CERN Document Server

    Nikolski, Nikolai


    The 2-volume-book is an updated, reorganized and considerably enlarged version of the previous edition of the Research Problem Book in Analysis (LNM 1043), a collection familiar to many analysts, that has sparked off much research. This new edition, created in a joint effort by a large team of analysts, is, like its predecessor, a collection of unsolved problems of modern analysis designed as informally written mini-articles, each containing not only a statement of a problem but also historical and metho- dological comments, motivation, conjectures and discussion of possible connections, of plausible approaches as well as a list of references. There are now 342 of these mini- articles, almost twice as many as in the previous edition, despite the fact that a good deal of them have been solved!

  2. Mathematical problems in meteorological modelling

    CERN Document Server

    Csomós, Petra; Faragó, István; Horányi, András; Szépszó, Gabriella


    This book deals with mathematical problems arising in the context of meteorological modelling. It gathers and presents some of the most interesting and important issues from the interaction of mathematics and meteorology. It is unique in that it features contributions on topics like data assimilation, ensemble prediction, numerical methods, and transport modelling, from both mathematical and meteorological perspectives. The derivation and solution of all kinds of numerical prediction models require the application of results from various mathematical fields. The present volume is divided into three parts, moving from mathematical and numerical problems through air quality modelling, to advanced applications in data assimilation and probabilistic forecasting. The book arose from the workshop “Mathematical Problems in Meteorological Modelling” held in Budapest in May 2014 and organized by the ECMI Special Interest Group on Numerical Weather Prediction. Its main objective is to highlight the beauty of the de...

  3. What’s Your Problem?

    DEFF Research Database (Denmark)

    Knudsen, Sanne

    problem-based genres, nor in how these generic competencies develop during their time at university. In this paper, I intend to present and discuss a genre analysis of problem-oriented student reports focusing in particular on how problem-oriented elements are represented in this writing and on how......In order to teach writing and to facilitate reflective learning, we need to know and to understand the actual writing and writing processes of our students - and in order to do so, we need research on what students think, want and write. Fostering critical thinking is one of the central aims...... of university, and during the last decades we have experienced a boom in student-oriented learning approaches specifically aiming at generating and supporting critical thinking and writing. As a result, new genres are born, in which students are expected to use and transform knowledge in a manner which...

  4. The Random Quadratic Assignment Problem (United States)

    Paul, Gerald; Shao, Jia; Stanley, H. Eugene


    The quadratic assignment problem, QAP, is one of the most difficult of all combinatorial optimization problems. Here, we use an abbreviated application of the statistical mechanics replica method to study the asymptotic behavior of instances in which the entries of at least one of the two matrices that specify the problem are chosen from a random distribution P. Surprisingly, the QAP has not been studied before using the replica method despite the fact that the QAP was first proposed over 50 years ago and the replica method was developed over 30 years ago. We find simple forms for C min and C max , the costs of the minimal and maximum solutions respectively. Notable features of our results are the symmetry of the results for C min and C max and their dependence on P only through its mean and standard deviation, independent of the details of P.

  5. Challenge problems for artificial intelligence

    Energy Technology Data Exchange (ETDEWEB)

    Selman, B.; Brooks, R.A.; Dean, T. [and others


    AI textbooks and papers of ten discuss the big questions, such as {open_quotes}how to reason with uncertainty{close_quotes}, {open_quotes}how to reason efficiently{close_quotes}, or {open_quotes}how to improve performance through learning.{close_quotes} It is more difficult, however, to find descriptions of concrete problems or challenges that are still ambitious and interesting, yet not so open-ended. The goal of this panel is to formulate a set of such challenge problems for the field. Each panelist was asked to formulate one or more challenges. The emphasis is on problems for which there is a good chance that they will be resolved within the next five to ten years.

  6. Food production -- problems and prospects. (United States)

    Anifowoshe, T O


    Improvements are needed in balancing the problems associated with population growth and food production. A review of the problems of rapid population growth and declining food production and suggestions for resolution are given. World population has increased over the past 10 years by 760 million, which is equal to adding the combined population of Africa and South America. Future increases are expected to bring total population to 6.1 billion by the year 2000 and 8.2 billion in 2025 (exponential increases). Food production/capita has declined since 1971 in the world and in Nigeria, particularly in the recent past. The food production problem is technical, environmental, social, political, and economic. Various scientific and technological methods for increasing food production are identified: mechanization, irrigation, use of fertilizers, control of weeds and insects, new varieties of farm animals or high-yielding strains of grain, land reclamation, soil conservation, river basin development, adequate storage facilities, infrastructure development, and birth control. Economic and social approaches involve short-term and long-term strategies in social readjustment and institutional change. For instance, large scale farmers should become contract growers for certain firms. Bureaucratic red tape should be eliminated in institutions which provide agricultural services. Environmental problems need urgent attention. Some of these problems are soil erosion from mechanization, water salinization from irrigation, accumulation of DDT in food and water and animal life from pesticide use, and water pollution from chemical fertilizers. Food production can be increased with more ecologically sound practices. Information about weather and weather forecasting allows for more suitable land management. The influence of rainfall (the amount and distribution) in Nigeria is greater than any other climatic factor. Solar radiation is a significant feature in production of dry matter and

  7. [Biophysical problems of oligopeptide regulation]. (United States)

    Zamiatinin, A A


    A number of physical problems arising in studies of the relationship between the structure and function of natural peptide molecules consisting of 2-50 amino acid residues were considered. Among these are the determination of functionally significant sizes of molecules and their configurations, a search for general principles of classification, and a study of the mechanisms of delivery of oligopeptide molecules and their binding to receptor structures. The natural concentrations and coefficients of diffusion of oligopeptides were compared with the time of their real functioning. The solubility of these and other problems was assessed.

  8. Interactive problem solving using LOGO

    CERN Document Server

    Boecker, Heinz-Dieter; Fischer, Gerhard


    This book is unique in that its stress is not on the mastery of a programming language, but on the importance and value of interactive problem solving. The authors focus on several specific interest worlds: mathematics, computer science, artificial intelligence, linguistics, and games; however, their approach can serve as a model that may be applied easily to other fields as well. Those who are interested in symbolic computing will find that Interactive Problem Solving Using LOGO provides a gentle introduction from which one may move on to other, more advanced computational frameworks or more

  9. The three-body problem

    CERN Document Server

    Marchal, Christian


    Recent research on the theory of perturbations, the analytical approach and the quantitative analysis of the three-body problem have reached a high degree of perfection. The use of electronics has aided developments in quantitative analysis and has helped to disclose the extreme complexity of the set of solutions. This accelerated progress has given new orientation and impetus to the qualitative analysis that is so complementary to the quantitative analysis. The book begins with the various formulations of the three-body problem, the main classical results and the important questions and conje

  10. Fluid mechanics problems and solutions

    CERN Document Server

    Spurk, Joseph H


    his collection of over 200 detailed worked exercises adds to and complements the textbook Fluid Mechanics by the same author, and illustrates the teaching material through examples. In the exercises the fundamental concepts of Fluid Mechanics are applied to obtaining the solution of diverse concrete problems, and in doing this the student's skill in the mathematical modeling of practical problems is developed. In addition, 30 challenging questions without detailed solutions have been included, and while lecturers will find these questions suitable for examinations and tests, the student himself can use them to check his understanding of the subject.

  11. Iron deficiency - a global problem

    International Nuclear Information System (INIS)

    Ali, S.M.


    Iron deficiency is an important nutritional global problem. This paper contains summery of information gathered from a dietary survey as iron deficiency anaemia is major public health problem in many developing countries including Pakistan. Comparison of anaemia in different age group and sex versus various regions in the world are given. In Pakistan also anaemia is widespread. According to the report of Micro-Nutrient survey of Pakistan 40% of the population are found to have low level of haemoglobin, more than half of pregnant women suffered from marginal or deficient haemoglobin. (A.B.)

  12. Inverse Problems in Economic Measurements (United States)

    Shananin, A. A.


    The problem of economic measurements is discussed. The system of economic indices must reflect the economic relations and mechanisms existing in society. An achievement of the XX century is the development of a system of national accounts and the gross domestic product index. However, the gross domestic product index, which is related to the Hamilton-Pontryagin function in extensive economic growth models, turns out to be inadequate under the conditions of structural changes. New problems of integral geometry related to production models that take into account the substitution of production factors are considered.

  13. Generalizations of the Brachistochrone Problem


    Gemmer, J.; Umble, R.; Nolan, M.


    Consider a frictionless surface S in a gravitational field that need not be uniform. Given two points A and B on S, what curve is traced out by a particle that starts at A and reaches B in the shortest time? This paper considers this problem on simple surfaces such as surfaces of revolution and solves the problem two ways: First, we use conservation of mechanical energy and the Euler-Lagange equation; second, we use geometrical optics and the eikonal equation. We conclude with a discussion of...

  14. Size Estimates in Inverse Problems

    KAUST Repository

    Di Cristo, Michele


    Detection of inclusions or obstacles inside a body by boundary measurements is an inverse problems very useful in practical applications. When only finite numbers of measurements are available, we try to detect some information on the embedded object such as its size. In this talk we review some recent results on several inverse problems. The idea is to provide constructive upper and lower estimates of the area/volume of the unknown defect in terms of a quantity related to the work that can be expressed with the available boundary data.

  15. Psychosocial Problems during Infertility Treatment

    Directory of Open Access Journals (Sweden)

    Nurcan Kirca


    Full Text Available Infertility is a complex situation crisis which is often psychologically-threatening and emotionally stressful for both partners as well as economically expensive and causes physical pain due to the operations performed for diagnosis and treatment purposes. Infertility has physical, psychological, social, emotional and financial impacts. Infertile couples are under a great social pressure, and need to conceal the problem as it is exceptionally private for them. Infertile individuals are destitute of support when they do not share their pregnancy problems with their families and relatives. Couples define their infertility experience as the most stressful experience of their lives.

  16. Satellite communications: possibilities and problems

    International Nuclear Information System (INIS)

    Hine, M.


    Communication links via satellites are becoming available in Europe, both as part of the development of the telephone system and as special services aimed at data traffic. They offer the possibility of speeds between 50 kb/s and 2 Mb/s, without the problems and long term commitments of long distance land lines. Such links are provided by the PTT's as circuits which can be booked for variable periods, and have error rates which can be very low and well controlled. Problems in networking can arise from the satellite delay, particularly if errors occur in the local connections, and from the leased circuit and tariff philosophies of the PTT's. (Auth.)

  17. On Labeled Traveling Salesman Problems

    DEFF Research Database (Denmark)

    Couetoux, Basile; Gourves, Laurent; Monnot, Jerome


    We consider labeled Traveling Salesman Problems, defined upon a complete graph of n vertices with colored edges. The objective is to find a tour of maximum (or minimum) number of colors. We derive results regarding hardness of approximation, and analyze approximation algorithms for both versions...

  18. Adaptive discretisation of shell problems

    Energy Technology Data Exchange (ETDEWEB)

    Hecht, A.; Carstensen, C.; Zarrabi, D. [Kiel Univ. (Germany)


    A seven parameter Reissner-Mindlin shell kinematic is employed for a elastoplastic material with hardening. The resulting nonlinear minimization problem is discretised within a finite element method on the mid surface of the shell. A posteriori error estimates are discussed and related adaptive algorithms are presented. Numerical examples illustrate the theoretical results. (orig.)

  19. Youth Problems on Indian Reservations. (United States)

    Underhill, Ruth M., Ed.

    Juvenile delinquency was identified as the major problem affecting youth on Indian reservations. Causes for delinquency which were discussed included culture conflict, expectation of failure, unemployment, failure of homes and parents, discrimination, inadequate education, off-reservation schools, and alcoholism. Needs identified by tribal leaders…

  20. Childhood Obesity: A Heavy Problem (United States)

    Costley, Kevin C.; Leggett, Timothy


    The youth of today are faced with a big problem; they are becoming more obese every day. The time of children playing outside all day and being extremely active has been overtaken by the television and video games. The days of sitting down as a family and eating a good healthy meal has been replaced by the rush to the nearest fast food…

  1. Cavitation problems in sodium valves

    International Nuclear Information System (INIS)

    Elie, X.


    Cavitation poses few problems for sodium valves, in spite of the fact that the loops are not pressurized. This is no doubt due to the low flow velocities in the pipes. For auxiliary loop valves we are attempting to standardize performances with respect to cavitation. For economic reasons cavitation thresholds are approached with large diameter valves. (author)

  2. Urban Planning Problems of Agglomerations (United States)

    Olenkov, V. D.; Tazeev, N. T.


    The article explores the state of the air basin of the Chelyabinsk agglomeration and gives the examples of solutions for the pollution problems from the point of view of city planning. The main features and structure of the modern urban agglomerations are considered, the methods for determining their boundaries are studied and the main problems are identified. The study of the boundaries and territorial structure of the Chelyabinsk urban agglomeration is conducted, and a general description of the territory is given. The data on the change in the volume of pollutant emissions into the atmosphere and the index of atmospheric pollution for the period 2003-2015 are given basing on the annual comprehensive reports regarding the state of the environment. The review of the world experience of city-planning actions on the decision of ecological problems is carried out. The most suitable ways for the ecological problems solving in the Chelyabinsk agglomeration are considered. The authors give recommendations for the ecological situation improving in the territory of the Chelyabinsk agglomeration.

  3. Sexual Harrassment: A Hidden Problem. (United States)

    Sandler, Bernice R.; And Others


    The hidden but serious problem of sexual harassment of students and employees by college faculty is discussed, some statistics are given, and legal and court opinions outlined. Harassment as a violation of Title IX is analyzed, and implications for institutional action to curb it are outlined. (MSE)

  4. Education for complex problem solving

    DEFF Research Database (Denmark)

    Kjær-Rasmussen, Lone Krogh

    The Problem-Based Learning model as it is practiced at Aalborg University grew out of expectations for future graduates in the 1970s. Many changes and developments have taken place since then in the ways the principles and methodologies are practiced, due to changes in society and governmental...

  5. Non-Euclidean visibility problems

    Indian Academy of Sciences (India)

    We prove a visibility criterion and study orchard problem and the cardinality of visible points in large circles. Author Affiliations. Fernando Chamizo1. Departamento de Matemáticas, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain. Dates. Manuscript received: 14 November 2005. Proceedings ...

  6. A Problem in Graph Theory

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 12; Issue 1. A Problem in Graph Theory. K P Savithri. Think It Over Volume 12 Issue 1 January 2007 pp 81-81. Fulltext. Click here to view fulltext PDF. Permanent link: Author Affiliations.

  7. Family Problems and Youth Unemployment. (United States)

    de Goede, Martijn; Spruijt, Ed; Maas, Cora; Duindam, Vincent


    Examines how family and personal characteristics relate to the employment situation of adolescents (N=995) in Denmark. Results show that parental divorce, parental unemployment (only for males), low parental affective involvement, and adolescent relationship problems were related to youth unemployment, but educational career and work commitment…

  8. [Surgical problems of homeless people]. (United States)

    Witkiewicz, Wojciech; Gnus, Jan Janusz; Stankiewicz, Zuzanna; Kocot, Marta; Rasiewicz, Marcin


    Estimated quantity of homeless people in Poland is about 30.000. Health conditions of homeless depends on poor living conditions, alcohol abuse and lack of medical care. The aim of the study was to present surgical problems of homeless people at St. Brother Albert's Aid Society Shelter in Szczodre. In years 2009-2011 in St. Brother Albert's Aid Society Shelter in Szczodre 1053 homeless were provided outpatient surgical care. The frequency of occurrence of diseases rated on the basis of the medical examination, medical history and medical records. The patients were aged 20-82 years (median: 46 years). The most common surgical problem of homeless people was skin infectious such as scabies, lice, tinea and lower limb ulceration due to underlying chronic vanous insufficiency or due to sustained injury. Other problems requiering surgical care were: frostbite, abscesses, phlegmon, unhealed wounds, back pain and pain due to sustained injuries. Most frequent causes of homelessness were family problems, alcohol abuse, conflict with the law, loss of ocupation or loss of home. Surgical diseases of homeless people have multifactorial etiology. The most frequent diseases in our patients were skin infectious and lower limb ulcerations. Medical care oriented on specific needs of homeless people is particulary important because poor health condition is not only consequence but could also be the cause of homelessness.

  9. On the optimal sizing problem

    DEFF Research Database (Denmark)

    Vidal, Rene Victor Valqui


    The paper studies the problem of determining the number and dimensions of sizes of apparel so as to maximize profits. It develops a simple one-variable bisection search algorithm that gives the optimal solution. An example is solved interactively using a Macintosh LC and Math CAD, a mathematical...

  10. Dynamical problem of micropolar viscoelasticity

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging Solutions)

    The dynamic problem in micropolar viscoelastic medium has been investigated by employing eigen value approach after applying Laplace and Fourier transformations. An example of infinite space with concentrated force at the origin has been presented to illustrate the application of the approach. The integral transforms ...

  11. Clustering problems for geochemical data

    International Nuclear Information System (INIS)

    Kane, V.E.; Larson, N.M.


    The Union Carbide Corporation, Nuclear Division, Uranium Resource Evaluation Project uses a two-stage sampling program to identify potential uranium districts. Cluster analysis techniques are used in locating high density sampling areas as well as in identifying potential uranium districts. Problems are considered involving the analysis of multivariate censored data, laboratory measurement error, and data standardization

  12. The Problem of Private Language

    Directory of Open Access Journals (Sweden)

    M.A Abdollahi


    This language is, according to Wittgenstein, impossible because it leads to epistemological and semantic skepticism. The definition of private language contains two elements: the “privacy” and “referring to”. Wittgenstein shows how we may be trapped in solipsism and the only way to avoid this problem is to consider language as a social phenomenon.

  13. Reversibility in dynamic coordination problems

    Czech Academy of Sciences Publication Activity Database

    Kováč, Eugen; Steiner, Jakub

    -, č. 374 (2008), s. 1-50 ISSN 1211-3298 R&D Projects: GA MŠk LC542 Institutional research plan: CEZ:AV0Z70850503 Keywords : dynamic coordination problems * global games * Laplacian belief Subject RIV: AH - Economics

  14. The Problem of World Hunger. (United States)

    Czarra, Fred R.; Long, Cathryn J., Eds.


    The major hunger problem today is chronic undernutrition, the primary cause of which is poverty. Hunger can be alleviated through food supplements, nutrition programs, and disaster relief. It can be eliminated by redistributing existing wealth and producing enough food and through equitable economic growth and a world food security system. (CS)

  15. DSM-5: problems and suggestions


    Birgegård, Andreas; Groß, Gaby; de Man Lapidoth, Joakim; Norring, Claes


    The upcoming DSM5 will impact clinical work and research substantially, and we here point to a few problems that may have been overlooked. These concern inconsistencies and lack of clarity, and the future “not elsewhere classified” atypical anorexia nervosa category. We propose solutions in the form of working definitions and operationalizations to facilitate clinical implementation as well as streamline research.

  16. Ontological problems of contemporary linguistics

    Directory of Open Access Journals (Sweden)

    А В Бондаренко


    Full Text Available The article studies linguistic ontology problems such as evolution of essential-existential views of language, interrelation within Being-Language-Man triad, linguistics gnosiological principles, language essence localization, and «expression» as language metalinguistic unit as well as architectonics of language personality et alia.

  17. The Vessel Schedule Recovery Problem

    DEFF Research Database (Denmark)

    Brouer, Berit Dangaard; Plum, Christian Edinger Munk; Vaaben, Bo

    Maritime transportation is the backbone of world trade and is accountable for around 3% of the worlds CO2 emissions. We present the Vessel Schedule Recovery Problem (VSRP) to evaluate a given disruption scenario and to select a recovery action balancing the trade off between increased bunker...

  18. Problems with the PTH assays. (United States)

    Cavalier, Etienne; Delanaye, Pierre; Nyssen, Laurent; Souberbielle, Jean-Claude


    Even if the first assay for parathyroid hormone (PTH) was published in the early 1960s, its determination remains a challenge even today. Indeed, in the circulation, PTH is present in its active form (PTH 1-84), but many PTH fragments can also be present. These fragments accumulate when renal function declines and are recognized, at different extents, by the 2nd generation ("intact") PTH assays that are widely used in the clinical laboratories. Some assays, called "3rd generation PTH" do not recognize these fragments, but are not available everywhere. Hence, different problems are also linked with PTH determination. Among them, one can cite the lack of a reference method, the lack of standardization of the assays and, sometimes, the lack of consistent reference range. We can also point out stability problems and a large intra-individual variation. A workgroup is working on these problems under the auspices of the IFCC and we hope that some of these problems will be resolved in the next years. In this article, we will discuss all the possible issues of PTH determination. Copyright © 2015. Published by Elsevier Masson SAS.

  19. Solution of the Transmission Problem

    Czech Academy of Sciences Publication Activity Database

    Medková, Dagmar


    Roč. 110, č. 3 (2010), s. 1489-1500 ISSN 0167-8019 Institutional research plan: CEZ:AV0Z10190503 Keywords : Laplace equation * transmission problem * single layer potential * double layer potential Subject RIV: BA - General Mathematics Impact factor: 0.979, year: 2010

  20. Sour landfill gas problem solved

    Energy Technology Data Exchange (ETDEWEB)

    Nagl, G.; Cantrall, R. [Wheelabrator Clean Air Systems, Inc., Schaumburg, IL (United States)


    In Broward County, Fla., near Pompano Beach, Waste Management of North America (WMNA, a subsidiary of WMX Technologies, Oak Brook, IL) operates the Central Sanitary Landfill and Recycling Center, which includes the country`s largest landfill gas-to-energy plant. The landfill consists of three collection sites: one site is closed, one is currently receiving garbage, and one will open in the future. Approximately 9 million standard cubic feet (scf) per day of landfill gas is collected from approximately 300 wells spread over the 250-acre landfill. With a dramatic increase of sulfur-containing waste coming to a South Florida landfill following Hurricane Andrew, odors related to hydrogen sulfide became a serious problem. However, in a matter of weeks, an innovative desulfurization unit helped calm the landfill operator`s fears. These very high H{sub 2}S concentrations caused severe odor problems in the surrounding residential area, corrosion problems in the compressors, and sulfur dioxide (SO{sub 2}) emission problems in the exhaust gas from the turbine generators.

  1. Statistical and Computational Inverse Problems

    CERN Document Server

    Kaipio, Jari


    Develops the statistical approach to inverse problems with an emphasis on modeling and computations. The book discusses the measurement noise modeling and Bayesian estimation, and uses Markov Chain Monte Carlo methods to explore the probability distributions. It is for researchers and advanced students in applied mathematics.

  2. Building Collections. The Problem Novel (United States)

    Krapp, JoAnn Vergona


    Realistic fiction has changed dramatically over the years. Formerly a sentimental, family-oriented story, today's realism focuses on today's problems and the protagonist's struggle to overcome them. Parents, once portrayed as protectors of the children, now often are cast as failures, needing help themselves. Yesterday's taboo subjects--drugs,…

  3. Interactive Problem-Solving Interventions

    African Journals Online (AJOL)

    Frew Demeke Alemu

    various interactive problem solving methods. Track III Diplomacy refers to “people to people” search for common ground undertaken by individuals or private groups. This type of activity may involve organizing meetings and conferences, generating media exposure, and political and legal advocacy. 15 Wehrenfennig, Id., p.

  4. Problem Keilmuan Pendidikan Agama Islam

    Directory of Open Access Journals (Sweden)

    M Saekan Muchith


    Full Text Available THE SCIENTIFIC PROBLEM OF ISLAMIC EDUCATION. This paper aims to study the scientific problems of Islamic education. This is because the Islamic religious education (including the Islamic educational institutions such as STAIN, IAIN and UIN is unique when compared to other sciences and institutions. The word “Islam” has its own characteristic which involves the science and the institution. Therefore, the science of Islamic education and Islamic education institutions must be able to carry out the vision of Islam as a religion of peace. Science of Islamic education and Islamic education institutions must be able to carry out the vision and mission of the Islamic religion in the context of ritual, muamalah or nationality. Consequently Islamic science must be able to formulate the structure and format of science that addresses the problems faced by Muslims. The slow quality of Islamic science and the quality of Islamic education institutions were triggered by problems called dichotomies science that exists only in debate. This leads to the less optimal performance of Islamic science, it is not directly able to formulate how this science is able to contribute to society. For the further implication, Islamic science became stagnant in the corridors of “science for science” and “discourse to discourse” that can only be read and debated.

  5. Non-Euclidean visibility problems

    Indian Academy of Sciences (India)

    FERNANDO CHAMIZO. Departamento de Matemáticas, Facultad de Ciencias, Universidad Autónoma de Madrid, 28049 Madrid, Spain. MS received 14 November 2005. Abstract. We consider the analog of visibility problems in hyperbolic plane (repre- sented by Poincaré half-plane model H), replacing the standard lattice Z ...

  6. Security Problems of Mobile Technologies

    Directory of Open Access Journals (Sweden)

    A. G. Beltov


    Full Text Available The article provides an overview of security problems which exist in the mobile devices. The main technologies aimed to protect the phones from various types of attacks are considered. The authors justify the necessity of developing new improved tools and methods to ensure the safety of such devices.

  7. The Scientist as Problem Solver. (United States)


    history. or imagined history. no magic and no mystery Each step appears to proceed. if not inexorably at least plausibly from the preceding one If the...discovery process appears quite unremarkable. The problem was found in the literatue (Goodwin S paper). and it can be represented in a quite standard way by

  8. Quantum Statistics and Entanglement Problems


    Trainor, L. E. H.; Lumsden, Charles J.


    Interpretations of quantum measurement theory have been plagued by two questions, one concerning the role of observer consciousness and the other the entanglement phenomenon arising from the superposition of quantum states. We emphasize here the remarkable role of quantum statistics in describing the entanglement problem correctly and discuss the relationship to issues arising from current discussions of intelligent observers in entangled, decohering quantum worlds.

  9. Dental Health and Orthodontic Problems (United States)

    ... Plaster models of the teeth are made How Orthodontic Problems are Treated If you were a “metal mouth” as a teenager, you’ll immediately notice that modern dental appliances are less conspicuous than the braces you wore. “ ...

  10. What is the Burnside Problem?

    Indian Academy of Sciences (India)

    The construction shows the existence of an infinite group which is finitely generated and all of whose elements have finite p-power order for some prime p. The orders of the elements are unbounded, and thus, this is not a counterexample to the Burnside problem where the torsion is bounded. Burnside's contributions to ...

  11. The Child-Fat Problem. (United States)

    Eberstadt, Mary


    Experts believe that child obesity is a serious medical problem that affects people in all socioeconomic groups. Suggests that there is a relationship between absentee parents, particularly mothers, and obese children, focusing on working/absentee mothers, television watching habits, the prophylactic effect of breastfeeding, and poor exercise…

  12. Problem Solvers' Conceptions about Osmosis. (United States)

    Zuckerman, June T.


    Discusses the scheme and findings of a study designed to identify the conceptual knowledge used by high school students to solve a significant problem related to osmosis. Useful tips are provided to teachers to aid students in developing constructs that maximize understanding. (ZWH)

  13. Engineering design problems of TFTR

    International Nuclear Information System (INIS)

    Lee, D.


    Design of the TFTR poses special engineering problems as a result of constraints posed by the physics requirements of the fusion experiments. The ratio of plasma major and minor radii and the associated magnetic field strength required to achieve desired plasma conditions, the required confinement time, the two-component plasma concept, the complications of providing shielding from the 14 MeV neutrons and the necessity to control the inventory of tritium fuel, all constitute problems which, often, in actuality, must be approached as materials problems. The complex, precision structures must satisfy various criteria, for example, low magnetic permeability, high electrical resistivity, resistance to neutron activation and high damage tolerance. Another constraint in the engineering design of TFTR is the requirement to optimize access to machine components for maintenance and repair. Many of the problems associated with accessibility have been resolved: the vacuum vessel has been designed as a ten-segment vessel; the igloo shielding of the machine is composed of interlocking blocks of boron-loaded concrete; the center column is designed in three segments. Current engineering emphasis is on finalizing design of the toroidal field coils, lower poloidal field coils, vacuum vessel liners and limiters and peripheral systems such as the vacuum pumping system and arrangement of diagnostics

  14. Eldercare at Home: Hearing Problems (United States)

    ... members and friends to comment on how much communication has improved when your mother is wearing the hearing aid. If your mother is concerned about the appearance of a hearing aid, tell her that most women can style their hair to cover the hearing aids. Problem " ...



    Isac Florin Lucian; Rusu Sergiu; Cureteanu Radu Silviu


    Companies that embrace client orientation are preoccupied by measuring the level of satisfaction of those who consume their products or utilizes their products. That is why, customer satisfaction has to be transposed in measurable parameters that can be understood and influenced. Nevertheless, measuring customer satisfaction involves a lot of problems.

  16. Frames and extension problems I

    DEFF Research Database (Denmark)

    Christensen, Ole


    In this article we present a short survey of frame theory in Hilbert spaces. We discuss Gabor frames and wavelet frames and set the stage for a discussion of various extension principles; this will be presented in the article Frames and extension problems II (joint with H.O. Kim and R.Y. Kim)....

  17. Problems in unification and supergravity

    International Nuclear Information System (INIS)

    Farrar, G.; Henyey, F.


    Problems in unification of the various gauge groups, quantum gravity, supersymmetry and supergravity, compact dimensions of space-time, and conditions at the beginning of the universe are discussed. Separate entries were prepared for the data base for the 15 papers presented

  18. Problems in unification and supergravity

    Energy Technology Data Exchange (ETDEWEB)

    Farrar, G.; Henyey, F. (eds.)


    Problems in unification of the various gauge groups, quantum gravity, supersymmetry and supergravity, compact dimensions of space-time, and conditions at the beginning of the universe are discussed. Separate entries were prepared for the data base for the 15 papers presented. (WHK)

  19. What is the Burnside Problem?

    Indian Academy of Sciences (India)

    "The time has come now," as the chivalrous professor said, "to talk of such things" If G is a torsion gro'llp - that is, a group in which all elements are of finite order, ... internet search demonstrates this), is an elementary count- ing lemma erroneously known as Burnside's lemma which is not due to him! 1. Burnside Problem for ...

  20. Inverse problem in radionuclide transport

    International Nuclear Information System (INIS)

    Yu, C.


    The disposal of radioactive waste must comply with the performance objectives set forth in 10 CFR 61 for low-level waste (LLW) and 10 CFR 60 for high-level waste (HLW). To determine probable compliance, the proposed disposal system can be modeled to predict its performance. One of the difficulties encountered in such a study is modeling the migration of radionuclides through a complex geologic medium for the long term. Although many radionuclide transport models exist in the literature, the accuracy of the model prediction is highly dependent on the model parameters used. The problem of using known parameters in a radionuclide transport model to predict radionuclide concentrations is a direct problem (DP); whereas the reverse of DP, i.e., the parameter identification problem of determining model parameters from known radionuclide concentrations, is called the inverse problem (IP). In this study, a procedure to solve IP is tested, using the regression technique. Several nonlinear regression programs are examined, and the best one is recommended. 13 refs., 1 tab

  1. Problem Gambling on College Campuses (United States)

    McComb, Jennifer L.; Hanson, William E.


    The vast majority of college students gamble, with some doing so problematically. This article discusses gambling and problem gambling among college students, framing it as an emerging health issue on college campuses nationwide. Given that 4 out of 5 college students admit to gambling, and that approximately 8% gamble problematically, it is…

  2. Counting problems for number rings

    NARCIS (Netherlands)

    Brakenhoff, Johannes Franciscus


    In this thesis we look at three counting problems connected to orders in number fields. First we study the probability that for a random polynomial f in Z[X] the ring Z[X]/f is the maximal order in Q[X]/f. Connected to this is the probability that a random polynomial has a squarefree

  3. The Football Team Composition Problem

    DEFF Research Database (Denmark)

    Pantuso, Giovanni


    Most professional European football clubs are well-structured businesses. Therefore, the financial performance of investments in players becomes crucial. In this paper, after the problem is discussed and formalized, an optimization model with the objective of maximizing the expected value...

  4. From 'troublemakers' to problem solvers

    DEFF Research Database (Denmark)

    Frandsen, Martin Severin; Pfeiffer Petersen, Lene


    in a disadvantaged neighbourhood in the suburbs of Copenhagen, designed and constructed colourful and imaginative dustbins to handle problems with local littering. The project was successful in creating an increased local awareness of waste management and reducing the amount of litter. However, the more important...

  5. Malaysian Serials: Issues and Problems. (United States)

    Bahri, Che Norma

    This paper analyzes the issues and problems while looking at the trends and developments of serials publishing in Malaysia. The first section provides background; topics addressed include the country and people of Malaysia, the history of serials publishing in Malaysia, categories and formats of serials publishing, academic publications,…

  6. STEM education and Fermi problems (United States)

    Holubova, Renata


    One of the research areas of Physics education is the study of the educational process. Investigations in this area are aimed for example on the teaching and learning process and its results. The conception of STEM education (Science, Technology, Engineering, and Mathematics) is discussed - it is one possible approach to the preparation of the curriculum and the focus on the educational process at basic and secondary schools. At schools in the Czech Republic STEM is much more realized by the application of interdisciplinary relations between subjects Physics-Nature-Technique. In both conceptions the aim is to support pupils' creativity, critical thinking, cross-curricular links. In this context the possibility of using Fermi problems in teaching Physics was discussed (as an interdisciplinary and constructivist activity). The aim of our research was the analysis of Fermi problems solving strategies, the ability of pupils to solve Fermi problems. The outcome of our analysis was to find out methods and teaching strategies which are important to use in teaching - how to solve qualitative and interdisciplinary tasks in physics. In this paper the theoretical basis of STEM education and Fermi problems will be presented. The outcome of our findings based on the research activities will be discussed so as our experiences from 10 years of Fermi problems competition that takes place at the Science Faculty, Palacky University in Olomouc. Changes in competencies of solving tasks by our students (from the point of view in terms of modern, activating teaching methods recommended by theory of Physics education and other science subjects) will be identified.

  7. Infertility as a psychological problem. (United States)

    Podolska, Magdalena Z; Bidzan, Mariola


    Recently there has been enormous progress in couple infertility treatment and diagnostics. Some couples cannot conceive despite the fact that there seems to be no objective somatic or immunologic reasons. In such situations gynaecologists are helpless and couples may be overwhelmed by a sense of defeat and hopelessness. Thus, consulting a psychologist or therapist on how to cope better with the problem may be a good solution. The objective of the following paper is to discuss the dilemmas of couples undergoing infertility treatment, related psychological problems, and to determine the need for psychological and therapeutic support. The study demonstrates numerous infertility causes and concludes that there is no universal method of dealing with them. Very frequently psychological and somatic problems overlap. Psychological causes are often the primary factors, but sometimes they are secondary derivatives of the therapeutic process. A wide scope of factors must be considered to attempt psychological analysis of patients treated for infertility including the influence of the family and relations within, reaction to the diagnosis and suggested treatment, the influence of religion on the treatment, the evaluation of the relations in the family of procreation, sexual life assessment, the sense of a woman's self-esteem and self-acceptance. Basing on empirical analysis it was concluded that all women treated for infertility want to create a full family. They have problems in coping with emotional liability during treatment and a sense of fear and failure. Understanding the psychological mechanisms observed in patients treated for infertility might help to diagnose the causes of their problems with facing the new, extremely difficult situation.

  8. Formal language constrained path problems

    Energy Technology Data Exchange (ETDEWEB)

    Barrett, C.; Jacob, R.; Marathe, M.


    In many path finding problems arising in practice, certain patterns of edge/vertex labels in the labeled graph being traversed are allowed/preferred, while others are disallowed. Motivated by such applications as intermodal transportation planning, the authors investigate the complexity of finding feasible paths in a labeled network, where the mode choice for each traveler is specified by a formal language. The main contributions of this paper include the following: (1) the authors show that the problem of finding a shortest path between a source and destination for a traveler whose mode choice is specified as a context free language is solvable efficiently in polynomial time, when the mode choice is specified as a regular language they provide algorithms with improved space and time bounds; (2) in contrast, they show that the problem of finding simple paths between a source and a given destination is NP-hard, even when restricted to very simple regular expressions and/or very simple graphs; (3) for the class of treewidth bounded graphs, they show that (i) the problem of finding a regular language constrained simple path between source and a destination is solvable in polynomial time and (ii) the extension to finding context free language constrained simple paths is NP-complete. Several extensions of these results are presented in the context of finding shortest paths with additional constraints. These results significantly extend the results in [MW95]. As a corollary of the results, they obtain a polynomial time algorithm for the BEST k-SIMILAR PATH problem studied in [SJB97]. The previous best algorithm was given by [SJB97] and takes exponential time in the worst case.

  9. Governance of wicked climate adaptation problems

    NARCIS (Netherlands)

    Termeer, C.J.A.M.; Dewulf, A.; Breeman, G.E.


    Climate change adaptation has been called a “wicked problem par excellence.” Wicked problems are hard to define because ‘the formulation of the problem is the problem; they are considered a symptom of another problem; they are highly resistant to solutions and extremely interconnected with other

  10. The Survey of Jimma University Students Problems

    African Journals Online (AJOL)


    Key Words: Economic problems, Social problems, Psychological problems, Academic problems, students. INTRODUCTION .... Reasons given by students for poor academic performance, Jimma University,. June 2002. Reasons. No of Students (%) ... sleep and other similar conditions - in 58. (41.0%), memory problem in 56 ...

  11. Predicting the Problem Behavior in Adolescents (United States)

    Karaman, Neslihan G.


    Problem statement: Problem behavior theory describes both protective factors and risk factors to explain adolescent problem behaviors, such as delinquency, alcohol use, and reckless driving. The theory holds that problem behaviors involving risky behavior are used by adolescents as a means to gain peer acceptance and respect. Problem behaviors…

  12. Problems on Divisibility of Binomial Coefficients (United States)

    Osler, Thomas J.; Smoak, James


    Twelve unusual problems involving divisibility of the binomial coefficients are represented in this article. The problems are listed in "The Problems" section. All twelve problems have short solutions which are listed in "The Solutions" section. These problems could be assigned to students in any course in which the binomial theorem and Pascal's…

  13. Constructing functional programs for grammar analysis problems

    NARCIS (Netherlands)

    Jeuring, J.T.; Swierstra, S.D.


    This paper discusses the derivation of functional programs for grammar analysis problems, such as the Empty problem and the Reachable problem. Grammar analysis problems can be divided into two classes: top-down problems such as Follow and Reachable, which are described in terms of the contexts of

  14. Radon: A health problem and a communication problem

    International Nuclear Information System (INIS)

    Johnson, R.H.


    The US Environmental Protection Agency (USEPA) is making great efforts to alert the American public to the potential health risks of radon in homes. The news media have widely publicized radon as a problem; state and local governments are responding to public alarms; and hundreds of radon open-quotes expertsclose quotes are now offering radon detection and mitigation services. Apparently, USEPA's communication program is working, and the public is becoming increasingly concerned with radon. But are they concerned with radon as a open-quotes healthclose quotes problem in the way USEPA intended? The answer is yes, partly. More and more, however, the concerns are about home resale values. Many homebuyers are now deciding whether to buy on the basis of a single radon screening measurement, comparing it with USEPA's action guide of 4 pCi L -1 . They often conclude that 3.9 is OK, but 4.1 is not. Here is where the communication problems begin. The public largely misunderstands the significance of USEPA's guidelines and the meaning of screening measurements. Seldom does anyone inquire about the quality of the measurements, or the results of USEPA performance testing? Who asks about the uncertainty of lifetime exposure assessments based on a 1-hour, 1-day, 3-day, or even 30-day measurement? Who asks about the uncertainty of USEPA's risk estimates? Fortunately, an increasing number of radiation protection professions are asking such questions. They find that USEPA's risk projections are based on many assumptions which warrant further evaluation, particularly with regard to the combined risks of radon and cigarette-smoking. This is the next communication problem. What are these radiation professions doing to understand the bases for radon health-risk projections? Who is willing to communicate a balanced perspective to the public? Who is willing to communicate the uncertainty and conservatism in radon measurements and risk estimates?

  15. On theoretical aspects of mixture problems

    Directory of Open Access Journals (Sweden)

    François Dubeau


    Full Text Available Mixture problems are basic but important problems in Operations Research. In this paper we consider variants of the basic linear mixture problem and indicate mathematical links between them.

  16. Improving mathematical problem solving : A computerized approach

    NARCIS (Netherlands)

    Harskamp, EG; Suhre, CJM

    Mathematics teachers often experience difficulties in teaching students to become skilled problem solvers. This paper evaluates the effectiveness of two interactive computer programs for high school mathematics problem solving. Both programs present students with problems accompanied by instruction

  17. Children's Health Problems and Maternal Work Status. (United States)

    Salkever, David S.


    This paper estimates the influence on working mothers' employment status of children's health problems. Effects are estimated for several different types of families, various groups of health problems, and differing degrees of problem severity. (CT)

  18. Inverse problems for difference equations with quadratic ...

    African Journals Online (AJOL)

    Inverse problems for difference equations with quadratic Eigenparameter dependent boundary conditions. Sonja Currie, Anne D. Love. Abstract. This paper inductively investigates an inverse problem for difference boundary value problems with boundary conditions that depend quadratically on the eigenparameter.

  19. PTSD and Problems with Alcohol Use (United States)

    ... Enter ZIP code here PTSD and Problems with Alcohol Use Public This section is for Veterans, General Public, Family, & Friends PTSD and Problems with Alcohol Use PTSD and alcohol use problems are often ...

  20. Modern solvers for Helmholtz problems

    CERN Document Server

    Tang, Jok; Vuik, Kees


    This edited volume offers a state of the art overview of fast and robust solvers for the Helmholtz equation. The book consists of three parts: new developments and analysis in Helmholtz solvers, practical methods and implementations of Helmholtz solvers, and industrial applications. The Helmholtz equation appears in a wide range of science and engineering disciplines in which wave propagation is modeled. Examples are: seismic inversion, ultrasone medical imaging, sonar detection of submarines, waves in harbours and many more. The partial differential equation looks simple but is hard to solve. In order to approximate the solution of the problem numerical methods are needed. First a discretization is done. Various methods can be used: (high order) Finite Difference Method, Finite Element Method, Discontinuous Galerkin Method and Boundary Element Method. The resulting linear system is large, where the size of the problem increases with increasing frequency. Due to higher frequencies the seismic images need to b...

  1. Stochastic problems in population genetics

    CERN Document Server

    Maruyama, Takeo


    These are" notes based on courses in Theoretical Population Genetics given at the University of Texas at Houston during the winter quarter, 1974, and at the University of Wisconsin during the fall semester, 1976. These notes explore problems of population genetics and evolution involving stochastic processes. Biological models and various mathematical techniques are discussed. Special emphasis is given to the diffusion method and an attempt is made to emphasize the underlying unity of various problems based on the Kolmogorov backward equation. A particular effort was made to make the subject accessible to biology students who are not familiar with stochastic processes. The references are not exhaustive but were chosen to provide a starting point for the reader interested in pursuing the subject further. Acknowledgement I would like to use this opportunity to express my thanks to Drs. J. F. Crow, M. Nei and W. J. Schull for their hospitality during my stays at their universities. I am indebted to Dr. M. Kimura...

  2. [Several problems concerning population investment]. (United States)

    Liu, Z


    Population investment is a major topic in the studies of population and economic relations. In this particular area, numerous theoretical and practical problems are still in need of solution. Concerning the problem of population concept, there are three different approaches: (1) to determine the definition of population investment from the relationship between the population growth and the capital from national income used for investment, including investment in the newly increased population and investment in the entire population; (2) to explain population investment from the economic viewpoint that people are producers; and (3) to explain population investment from the expense needed to change a simple labor force to a skillful labor force. The expenses include educational costs, maintanance spending, wages needed to compensate workers in labor, costs for workers to master and learn modern scientific techniques to be used for production, and the costs of keeping a young labor force in the next generation.

  3. The optimal graph partitioning problem

    DEFF Research Database (Denmark)

    Sørensen, Michael Malmros; Holm, Søren


    In this paper we consider the problem of partitioning the set of nodes in a graph in at most p classes, such that the sum of node weights in any class is not greater than the class capacity b, and such that the sum of edge weights, for edges connecting nodes in the same class, is maximal. This pr......In this paper we consider the problem of partitioning the set of nodes in a graph in at most p classes, such that the sum of node weights in any class is not greater than the class capacity b, and such that the sum of edge weights, for edges connecting nodes in the same class, is maximal...

  4. Modern problems in insurance mathematics

    CERN Document Server

    Martin-Löf, Anders


    This book is a compilation of 21 papers presented at the International Cramér Symposium on Insurance Mathematics (ICSIM) held at Stockholm University in June, 2013. The book comprises selected contributions from several large research communities in modern insurance mathematics and its applications. The main topics represented in the book are modern risk theory and its applications, stochastic modelling of insurance business, new mathematical problems in life and non-life insurance, and related topics in applied and financial mathematics. The book is an original and useful source of inspiration and essential reference for a broad spectrum of theoretical and applied researchers, research students and experts from the insurance business. In this way, Modern Problems in Insurance Mathematics will contribute to the development of research and academy–industry co-operation in the area of insurance mathematics and its applications.

  5. The Problem of Cinematic Imagination

    Directory of Open Access Journals (Sweden)

    Rafe McGregor


    Full Text Available The purpose of this paper is two-fold: to identify the problem of cinematic imagination, and then to propose a satisfactory solution. In part one I analyze the respective claims of Dominic McIver Lopes and Roger Scruton, both of whom question the scope of imagination in film, when compared to other art forms, on the basis of its perceptual character. In order to address these concerns I develop a hybrid of Gregory Currie’s model of cinematic imagination and Kendall Walton’s theory of make-believe in section two. Section three offers a reply to Lopes and Scruton, examining the problem in terms of the tension between the normativity of films as props and the employment of the creative imagination by audiences. I conclude with a solution that admits of two incompatible conceptions of cinematic imagination.

  6. Complex analogues of real problems

    DEFF Research Database (Denmark)

    Esdahl-Schou, Rune

    This thesis will be a mix of different problems in number theory. As such it is split into two natural parts. The rst part focuses on normal numbers and construction of numbers that are normal to a given complex base. It is written in the style of a thorough and introductory paper on that subject...... and Velani, and inspired by this An gave a different proof which provides a stronger result. The conjecture is concerned with intersections of certain sets in the plane and are as such a real problem. We will consider a slightly different setup where the real plane is replaced by the complex plane. Using...... geometrical interpretations we construct sets with properties similar to the sets considered in the real case. We then formulate a conjecture which can be interpreted as a complex version of Schmidt's original conjecture. Finally we construct a variant of Schmidt's game, to show a partial result leading us...

  7. Numerical models for differential problems

    CERN Document Server

    Quarteroni, Alfio


    In this text, we introduce the basic concepts for the numerical modelling of partial differential equations. We consider the classical elliptic, parabolic and hyperbolic linear equations, but also the diffusion, transport, and Navier-Stokes equations, as well as equations representing conservation laws, saddle-point problems and optimal control problems. Furthermore, we provide numerous physical examples which underline such equations. We then analyze numerical solution methods based on finite elements, finite differences, finite volumes, spectral methods and domain decomposition methods, and reduced basis methods. In particular, we discuss the algorithmic and computer implementation aspects and provide a number of easy-to-use programs. The text does not require any previous advanced mathematical knowledge of partial differential equations: the absolutely essential concepts are reported in a preliminary chapter. It is therefore suitable for students of bachelor and master courses in scientific disciplines, an...

  8. Networks in social policy problems

    CERN Document Server

    Scotti, marco


    Network science is the key to managing social communities, designing the structure of efficient organizations and planning for sustainable development. This book applies network science to contemporary social policy problems. In the first part, tools of diffusion and team design are deployed to challenges in adoption of ideas and the management of creativity. Ideas, unlike information, are generated and adopted in networks of personal ties. Chapters in the second part tackle problems of power and malfeasance in political and business organizations, where mechanisms in accessing and controlling informal networks often outweigh formal processes. The third part uses ideas from biology and physics to understand global economic and financial crises, ecological depletion and challenges to energy security. Ideal for researchers and policy makers involved in social network analysis, business strategy and economic policy, it deals with issues ranging from what makes public advisories effective to how networks influenc...

  9. World-wide environmental problems

    International Nuclear Information System (INIS)

    Wohlers, H.C.


    Man and the physical and natural resources necessary to support him in a civilized society are on a collision course. It is simple to say that man cannot continue to grow in number at an ever-increasing rate without a destructive effect upon the environment. Positive scientific proof for this impending calamity is not now available, yet many indications--sometimes physical and sometimes natural--point toward major world-wide environmental troubles in the near future. A number of environmental problems are described, particularly as they relate to the total world system. A computer model simulating future world-wide environmental trends from 1900 to 2100 A.D. is evaluated and suggested as a major tool for data-gathering purposes to determine the extent of world-wide environmental problems. It is suggested that scientists take an active role in the study of the environment, particularly in relation to man's future on earth

  10. An archetype hydrogen atmosphere problem

    International Nuclear Information System (INIS)

    Athay, R.G.; Mihalas, D.; Shine, R.A.


    Populations for the first three bound states and the continuum of hydrogen are determined for an isothermal, hydrostatic atmosphere at 20000K. The atmosphere is treated as being optically thin in the Balmer and Paschen continua and illuminated by continuum radiation at these wavelengths with prescribed radiation temperatures. The atmosphere is optically thick in the 2-1,3-1,3-2 and c-1 transitions. Three stages of approximation are treated: (1) radiative detailed balance in the 2-1, 3-1 and 3-2 transitions, (2) radiative detailed balance in the 3-1 and 3-2 transitions, and (3) all transitions out of detailed balance. The solution of this problem is non-trivial, and presents sufficient difficulty to have caused failure of at least one rather standard technique. The problem is thus a good archetype against which new methods, or new implementations of old methods may be tested. (Auth.)

  11. An archetype hydrogen atmosphere problem (United States)

    Athay, R. G.; Mihalas, D.; Shine, R. A.


    Populations for the first three bound states and the continuum of hydrogen are determined for an isothermal hydrostatic atmosphere at 20,000 K. The atmosphere is treated as optically thin in the Balmer and Paschen continua and illuminated by continuum radiation at these wavelengths with prescribed radiation temperatures. The atmosphere is optically thick in the 2-1, 3-1, 3-2 and c-1 transitions. Three stages of approximation are treated: (1) radiative detailed balance in the 2-1, 3-1 and 3-2 transitions, (2) radiative detailed balance in the 3-1 and 3-2 transitions, and (3) all transitions out of detailed balance. The solution of this problem is nontrivial and presents sufficient difficulty to have caused the failure of at least one rather standard technique. The problem is thus a good archetype against which new methods or new implementations of old methods may be tested.

  12. Adaptive Problem Solving by Analogy (United States)


    gestalt   psychologist  developed  a  number of  rules which prescribe when  and how  visual   features  are be bound  together.  There is however a...tracking,  visualization   of the working memory, and a script language for setting‐up and controlling simulations.  Summary and dissemination are presented in...set of  visual   features belong  to  the  same object).  The binding problem  is  also  relevant  to  problem solving as long as prior to finding a

  13. Retrofitting and the mu Problem

    Energy Technology Data Exchange (ETDEWEB)

    Green, Daniel; Weigand, Timo; /SLAC /Stanford U., Phys. Dept.


    One of the challenges of supersymmetry (SUSY) breaking and mediation is generating a {mu} term consistent with the requirements of electro-weak symmetry breaking. The most common approach to the problem is to generate the {mu} term through a SUSY breaking F-term. Often these models produce unacceptably large B{mu} terms as a result. We will present an alternate approach, where the {mu} term is generated directly by non-perturtative effects. The same non-perturbative effect will also retrofit the model of SUSY breaking in such a way that {mu} is at the same scale as masses of the Standard Model superpartners. Because the {mu} term is not directly generated by SUSY breaking effects, there is no associated B{mu} problem. These results are demonstrated in a toy model where a stringy instanton generates {mu}.

  14. Problem of professional personality formation

    Directory of Open Access Journals (Sweden)

    Pryazhnikova E.Yu.


    Full Text Available The article presents the current approaches to the problem of professional personality formation. It ana-lyzes the impact of professional identity of students on the choice of the specialist field they make. The article highlights certain aspects of the educational environment which promote to formation of compe-tences in students, relating to their choice of professional occupations. The article presents the analysis of students’ internal and external strivings after graduation from the university and their fulfillment.

  15. Corrosion problems of power engineering

    International Nuclear Information System (INIS)


    The proceedings contain 26 contributions, out of which 11 have been inputted in INIS. These are concerned with methods for the evaluation of corrosion resistance of materials for the nuclear industry, with examination of the corrosion behavior of composite overlays and of steels after the action of decontamination solutions, and with theoretical models of crack propagation. Corrosion problems of steam turbines, steam generator tubes and thermocouple bushings are discussed. (M.D.). 28 figs., 8 tabs., 63 refs

  16. Inverse problem in transformation optics


    Novitsky, Andrey V.


    The straightforward method of transformation optics implies that one starts from the coordinate transformation and determines the Jacobian matrix, the fields and material parameters of the cloak. However, the coordinate transformation appears as an optional function: it is not necessary to know it. We offer the solution of some sort of inverse problem: starting from the fields in the invisibility cloak we directly derive the permittivity and permeability tensors of the cloaking shell. This ap...

  17. Transition to thermohydrodynamic lubrication problem

    Czech Academy of Sciences Publication Activity Database

    Ciuperca, I. S.; Feireisl, Eduard; Jai, M.; Petrov, A.


    Roč. 75, č. 3 (2017), s. 391-414 ISSN 0033-569X EU Projects: European Commission(XE) 320078 - MATHEF Institutional support: RVO:67985840 Keywords : free boundary problems * lubrication * asymptotic approach * Stokes equation Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics Impact factor: 0.788, year: 2016

  18. Problems in decentralized data acquisition

    International Nuclear Information System (INIS)

    Eder, R.


    This paper describes INIS (International Nuclear Information System) which is operated by the International Atomic Energy Agency (IAEA) in collaboration with 73 Member States and 14 international organizations. INIS is a computerized system for collecting, processing and disseminating nuclear information. The collection and scanning of literature, input preparation and the dissemination of output are completely decentralized, the checking and merging of the information data are centralized. This paper shows the structure, management, processing and problem areas of this system. (Author)

  19. Providing solutions to engineering problems

    International Nuclear Information System (INIS)

    Connop, R.P.P.


    BNFL has acquired unique experience over a period of 40 years in specifying, designing and constructing spent fuel reprocessing and associated waste management plant. This experience is currently used to support a pound 5.5 billion capital investment programme. This paper reviews a number of engineering problems and their solutions to highlight BNFL experience in providing comprehensive specification, design and engineering and project management services. (author)

  20. Regularity results for asymptotic problems


    Isernia, Teresa


    Elliptic and parabolic equations arise in the mathematical description of a wide variety of phenomena, not only in the natural science but also in engineering and economics. To mention few examples, consider problems arising in different contexts: gas dynamics, biological models, the pricing of assets in economics, composite media. The importance of these equations from the applications' point of view is equally interesting from that of analysis, since it requires the design of novel techniqu...